Interparticle interactions and structure in nonideal solutions of human serum albumin studied by small-angle neutron scattering and Monte Carlo simulation

DEFF Research Database (Denmark)

Sjöberg, B.; Mortensen, K.

1994-01-01

of human serum albumin (HSA) up to a concentration of 0.26 g/cm(3) in 1.08 M NaCl. In order to obtain a model for the interactions we have combined the SANS data with results obtained by Monte Carlo simulations where we calculate the structure factor S(Q) and the pair correlation function g......Moderately or highly concentrated nonideal solutions of macromolecules are very important systems e.g. in biology and in many technical processes. In this work we have used the small-angle neutron scattering technique (SANS) to study the interactions and interparticle structure in solutions......(r). The advantage of using the Monte Carlo method is that completely general models for the particle shape and the interactions can be considered. It is found that the SANS data can be explained by a model where the shape of the HSA molecule is approximated by an ellipsoid of revolution with semiaxes a = 6.8 nm...

Micromechanical study of macroscopic friction and dissipation in idealised granular materials: the effect of interparticle friction

NARCIS (Netherlands)

Kruyt, Nicolaas P.; Gutkowski, Witold; Rothenburg, L.; Kowalewski, Tomasz A.

2004-01-01

Using Discrete Element Method (DEM) simulations with varying interparticle friction coefficient, the relation between interparticle friction coefficient and macroscopic continuum friction and dissipation is investigated. As expected, macroscopic friction and dilatancy increase with interparticle

Nanoparticle heterodimers: The role of size and interparticle gap distance on the optical response

Science.gov (United States)

Mokkath, Junais Habeeb

2018-05-01

Composite plasmonic nanostructures with controlled size, shape and relative arrangement is a subject of significant current research interest. Much of this is stimulated by the prospects by generating enormous near-field enhancements of the surface and interparticle gap regions for potential applications in surface-enhanced spectroscopies. In this manuscript, using time-dependent density functional theory (TDDFT) calculations, we investigate how the optical response in size matched homodimers and size mismatched heterodimers composed of Aluminum modify while varying the size and interparticle gap distances in the sub-nanometer range. Both systems show interesting optical response evolution. In particular, the size mismatched heterodimers show even more complex optical response evolution due to a symmetry-breaking in the system.

Improving the strength of ceramics by controlling the interparticle forces and rheology of the ceramic suspensions

International Nuclear Information System (INIS)

Chou, Yi-Ping

2001-01-01

This thesis describes a study of the modification of the interparticle forces of colloidal ceramic particles in aqueous suspensions in order to improve the microstructural homogeneity, and hence the reliability and mechanical performances, of subsequently formed ceramic compacts. A concentrated stable fine ceramic powder suspension has been shown to be able to generate a higher density of a ceramic product with better mechanical, and also electrical, electrochemical and optical, properties of the ceramic body. This is because in a colloidally stable suspension there are no aggregates and so defect formation, which is responsible for the ceramic body performance below its theoretical maximum, is reduced. In order to achieve this, it is necessary to form a well dispersed ceramic suspension by ensuring the interparticle forces between the particles are repulsive, with as a high a loading with particles as possible. By examining the rheological behaviour and the results of Atomic Force Microscope, the dispersion state of the suspensions and hence the interparticle forces can be analysed. In this study, concentrated ceramic suspensions were made from two kinds of zirconia powders, monoclinic (DK1) and yttria partially stabilised (HSY3) zirconia, in the presence of a dispersant, 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt (Tiron), in aqueous system. The optimum dispersant concentrations, where the viscosity and rheological moduli are the entire minimum, for DK1 and HSY3 suspensions, respectively, are 0.625% and 0.1%. The modifications of the interparticle forces were also achieved by pH adjustment and it was found that both of the suspensions at the optimum dispersant concentration were stable over the pH range 7 ∼ 10, which coincide with the results of the electrophoretic mobility measurements. Ceramic compacts have then been made by slip casting the suspensions of different dispersant concentration, followed by firing procedure. Mechanical properties of

Experimental investigation on dependency of interparticle distance in Coulomb crystal on various parameters

OpenAIRE

Adachi, Satoshi; Takayanagi, Masahiro; 足立　聡; 高柳　昌弘

2007-01-01

Dependency of interparticle distance in Coulomb crystal on various parameters such as plasma density, electron temperature, plasma potential and the Debye length are experimentally investigated. From the investigation, it is found that the interparticle distance is proportional to the Debye length.

A photo-tunable membrane based on inter-particle crosslinking for decreasing diffusion rates

KAUST Repository

Li, Song

2015-01-01

Functional polymeric membranes are widely used to adjust and control the diffusion of molecules. Herein, photosensitive poly(hydroxycinnamic acid) (PHCA) microspheres, which were fabricated by an emulsification solvent-evaporation method, were embedded into an ethyl cellulose matrix to fabricate composite membranes with a photo-tunable property. The photoreaction of PHCA is based on the [2 + 2] cycloaddition of cinnamic moieties upon irradiation with 365 nm light. Intra-particle crosslinking in PHCA microspheres was confirmed in the solution phase, while inter-particle crosslinking between adjacent PHCA microspheres dominated the solid membrane phase. The inter-particle crosslinking turned down the permeability of the composite membranes by 74%. To prove the applicability of the designed system, the composite membrane was coated on a model drug reservoir tablet. Upon irradiating the tablet with UV light, the original permeability decreased by 57%, and consequently the diffusion rate of the cargo (Rhodamine B) from the tablet slowed down. Most importantly, the tablet showed sustained release for over 10 days. This controllability can be further tuned by adjusting the membrane thickness. Composite membranes showed excellent processing reproducibility together with consistent mechanical properties. These results demonstrate that the incorporation of photosensitive PHCA microspheres in polymeric membranes provides a promising photo-tunable material for different applications including coating and separation. This journal is © The Royal Society of Chemistry 2015.

Plasmon interactions between gold nanoparticles in aqueous solution with controlled spatial separation

DEFF Research Database (Denmark)

Sendroiu, I.E.; Mertens, Stijn; Schiffrin, D.J.

2006-01-01

The effects of interparticle distance on the UV-visible absorption spectrum of gold nanocrystals aggregates in aqueous solution have been investigated. The aggregates were produced by ion-templated chelation of omega-mercaptocarboxylic acid ligands covalently attached to the nanoparticles surface....... Variation of the ligand chain length provides control over the interparticle separation in the aggregates. The UV-visible spectra consist typically of a single particle band and a secondary band at higher wavelengths associated with the formation of aggregates in solution. The position of the latter depends...

Effects of nonmagnetic interparticle forces on magnetorheological fluids

International Nuclear Information System (INIS)

Klingenberg, D J; Olk, C H; Golden, M A; Ulicny, J C

2010-01-01

Effects of nonmagnetic interparticle forces on the on- and off-state behavior of magnetorheological fluids are investigated experimentally and with particle-level simulations. Suspensions of iron particles in an aliphatic oil are modified by surface-active species. The modifications significantly alter the off-state properties, but have little impact on the field-induced stresses. Simulations show similar behavior. Off-state rheological properties are strongly influenced by van der Waals forces and modifications of the short-range repulsive forces. Field-induced stresses are less sensitive to the nonmagnetic forces.

Effects of nonmagnetic interparticle forces on magnetorheological fluids

International Nuclear Information System (INIS)

Klingenberg, D J; Olk, C K; Golden, M A; Ulicny, J C

2009-01-01

Effects of nonmagnetic interparticle forces on the on- and off-state behavior of MR fluids are investigated experimentally and with particle-level simulations. Suspensions of iron particles in an aliphatic oil are modified by surface-active species. The modifications significantly alter the off-state properties, but have little impact on the field-induced stresses. Simulations show similar behavior. Off-state rheological properties are strongly influenced by van der Waals forces and modifications of the short-range repulsive forces. Field-induced stresses are less sensitive to the nonmagnetic forces.

Modelling Inter-Particle Forces and Resulting Agglomerate Sizes in Cement-Based Materials

DEFF Research Database (Denmark)

Kjeldsen, Ane Mette; Geiker, Mette Rica

2005-01-01

The theory of inter-particle forces versus external shear in cement-based materials is reviewed. On this basis, calculations on maximum agglomerate size present after the combined action of superplasticizers and shear are carried out. Qualitative experimental results indicate that external shear ...

An examination of the interparticle contact area during sintering of W-0.3 wt pct Co

International Nuclear Information System (INIS)

Mitlin, D.; German, R.M.

1998-01-01

As a powder compact sinters, its microstructure evolves. One way to quantify the scale of the microstructure is to consider the interparticle contact area. This study examines two known models for calculating the interparticle contact area: the classic two-sphere model and the Voronoi cell model. Both models have particular assumptions about the microstructure that make them not applicable for treating densification to near full density with concurrent grain growth. The classic two-sphere model assumes a regular packing of particles and a perfectly spherical particle geometry and neglects an increasing particle coordination number with sintering. The Voronoi cell model assumes that the scale of the microstructure remains constant; i.e., as long as the compact is densifying, grain growth does not occur. The authors propose a modified Voronoi cell that accounts for an increasing grain size, making it applicable to a general case where grain growth occurs during sintering. The three models are compared to the interparticle contact area data, obtained by stereology techniques, for W-0.3 wt pct Co sintered from green state to near full density. The original Voronoi cell model fits the data only at low temperatures, before the onset of grain growth. Below approximately 90 pct relative density, the two-sphere model with an assumed coordination number of six (coordination number in a green compact) and the modified Voronoi cell model provide a good fit to the data. At higher densities, both models overestimate the interparticle contact area

Soil aggregate formation: the role of wetting-drying cycles in the genesis of interparticle bonding

Science.gov (United States)

Albalasmeh, Ammar; Ghezzehei, Teamrat

2013-04-01

Soil structure influences many soil properties including aeration, water retention, drainage, bulk density, and resistance to erosion and indirectly influences most biological and chemical processes that occur in and around soil. In nature, soil is continually exposed to wetting (e.g., rainfall and diffusive flow) and drying (e.g., evaporation, diffusive flow and plant uptake). These natural wetting and drying cycles of soils are physical events that profoundly affect the development of soil structure, aggregate stability, carbon (C) flux and mineralization. We hypothesize that drying of capillary water transports suspended and/or dissolved cementing agents toward inter-particle contacts and eventually deposits part of the colloidal mass forming inter-particle bonds. Here, we will show the role of wetting and drying cycles on soil aggregation and stabilization and how these cycles transport and deposit organic cementing agents at the inter-particle contact. We found that aggregates of sand and silt particles can be formed by subjecting loose particles to wetting-drying cycles in the presence of dilute solutions of organic matter that mimic root or microbial exudates. Moreover, majority of the organic matter was deposited in the contact region between the sand particles, where the water accumulates during drying. The model predictions and aggregate stability measurements are supported by scanning electron micrographs that clearly show the process of aggregate formation.

A theoretical study on the influence of gas adsorption on interparticle forces in powders

NARCIS (Netherlands)

Cottaar, E.J.E.; Rietema, K.

1986-01-01

Using data from the literature and some additional experiments it is investigated whether the interparticle forces in general and more specifically the cohesion between particles are influenced by the physisorption of gases. In this otherwise theoretical study the force to be applied to a particle

Controlling coulomb interactions in infrared stereometamaterials for unity light absorption

Science.gov (United States)

Mudachathi, Renilkumar; Moritake, Yuto; Tanaka, Takuo

2018-05-01

We investigate the influence of near field interactions between the constituent 3D split ring resonators on the absorbance and resonance frequency of a stereo metamaterial based perfect light absorber. The experimental and theoretical analyses reveal that the magnetic resonance red shifts and broadens for both the decreasing vertical and lateral separations of the constituents within the metamaterial lattice, analogous to plasmon hybridization. The strong interparticle interactions for higher density reduce the effective cross-section per resonator, which results in weak light absorption observed in both experimental and theoretical analyses. The red shift of the magnetic resonance with increasing lattice density is an indication of the dominating electric dipole interactions and we analyzed the metamaterial system in an electrostatic point of view to explain the observed resonance shift and decreasing absorption peak. From these analyses, we found that the fill factor introduces two competing factors determining the absorption efficiency such as coulomb interactions between the constituent resonators and their number density in a given array structure. We predicted unity light absorption for a fill factor of 0.17 balancing these two opposing factors and demonstrate an experimental absorbance of 99.5% at resonance with our 3D device realized using residual stress induced bending of 2D patterns.

Controlling Short-Range Interactions by Tuning Surface Chemistry in HDPE/Graphene Nanoribbon Nanocomposites.

Science.gov (United States)

Sadeghi, Soheil; Zehtab Yazdi, Alireza; Sundararaj, Uttandaraman

2015-09-03

Unique dispersion states of nanoparticles in polymeric matrices have the potential to create composites with enhanced mechanical, thermal, and electrical properties. The present work aims to determine the state of dispersion from the melt-state rheological behavior of nanocomposites based on carbon nanotube and graphene nanoribbon (GNR) nanomaterials. GNRs were synthesized from nitrogen-doped carbon nanotubes via a chemical route using potassium permanganate and some second acids. High-density polyethylene (HDPE)/GNR nanocomposite samples were then prepared through a solution mixing procedure. Different nanocomposite dispersion states were achieved using different GNR synthesis methods providing different surface chemistry, interparticle interactions, and internal compartments. Prolonged relaxation of flow induced molecular orientation was observed due to the presence of both carbon nanotubes and GNRs. Based on the results of this work, due to relatively weak interactions between the polymer and the nanofillers, it is expected that short-range interactions between nanofillers play the key role in the final dispersion state.

Algebra of strong and electroweak interactions

International Nuclear Information System (INIS)

Bolokhov, S.V.; Vladimirov, Yu.S.

2004-01-01

The algebraic approach to describing the electroweak and strong interactions is considered within the frames of the binary geometrophysics, based on the principles of the Fokker-Feynman direct interparticle interaction theories of the Kaluza-Klein multidimensional geometrical models and the physical structures theory. It is shown that in this approach the electroweak and strong elementary particles interaction through the intermediate vector bosons, are characterized by the subtypes of the algebraic classification of the complex 3 x 3-matrices [ru

Characterization and Correlation of Particle-Level Interactions to the Macroscopic Rheology of Powders, Granular Slurries, and Colloidal Suspensions

Energy Technology Data Exchange (ETDEWEB)

Poloski, Adam P.; Daniel, Richard C.; Rector, David R.; Bredt, Paul R.; Buck, Edgar C.; Berg, John C.; Saez, Avelino E.

2006-09-29

Hanford TRU tank sludges are complex mixtures of undissolved minerals and salt solids in an aqueous phase of high ionic strength. They show complex rheological behavior resulting from interactions at the macroscopic level, such as interparticle friction between grains in the coarse fraction, as well as from interactions at the nano-scale level, such as the agglomeration of colloidal particles. An understanding of how phenomena such as interparticle friction and aggregate stability under shear will allow better control of Hanford TRU tank sludges being processed for disposal. The project described in this report had two objectives. The first was to understand the physical properties and behavior of the Hanford transuranic (TRU) tank sludges under conditions that might exist during retrieval, treatment, packaging, and transportation for disposal at the Waste Isolation Pilot Plant (WIPP). The second objective was to develop a fundamental understanding of sludge physical properties by correlating the macroscopic behavior with interactions occurring at the particle/colloidal scale. These objectives were accomplished by: 1) developing continuum models for coarse granular slurries and 2) studying the behavior of colloidal agglomerates under shear and under irradiation.

Influence of the flip-flop interaction on a single plasmon transport in 1D waveguide

Science.gov (United States)

Ko, Myong-Chol; Kim, Nam-Chol; Ho, Nam-Chol; Ryom, Ju-Song; Hao, Zhong-Hua; Li, Jian-Bo; Wang, Qu-Quan

2017-12-01

Transport of a single plasmon in the 1D waveguide coupled to two emitters with the flip-flop interaction is discussed theoretically via the real-space approach. We showed that the transmission and reflection of a single plasmon could be changeable by adjusting the flip-flop coupling strength of the QDs, the interaction of QDs with the metallic nanowaveguide, interparticle distance of the QDs and detuning. Setting the interparticle distances properly results in the switching between the complete transmission and the complete reflection. Especially, our results show that the QDs with the flip-flop interaction play important role in the transport of the propagating single plasmon, which is relevant to the Förster resonance energy transfer from donor QD to acceptor QD.

Surface enhanced infrared spectroscopy using interacting gold nanowires

Energy Technology Data Exchange (ETDEWEB)

Neubrech, Frank; Weber, Daniel; Pucci, Annemarie [Kirchhoff-Institut fuer Physik, Heidelberg (Germany); Shen, Hong [Universite Troyes, Troyes (France); Lamy de la Chapelle, Marc [Universite Paris 13, Bobigny (France)

2009-07-01

We performed surface enhanced infrared spectroscopy (SEIRS) of molecules adsorbed on gold nanowires using synchrotron light of the ANKA IR-beamline at the Forschungszentrum Karlsruhe (Germany). Arrays of gold nanowires with interparticle spacings down to 30nm were prepared by electron beam lithography. The interparticle distance was reduced further by wet-chemically increasing the size of the gold nanowires. The growth of the wires was proofed using IR spectroscopy as well as scanning electron microscopy. After this preparation step, appropriate arrays of nanowires with an interparticle distance down to a few nanometers were selected to demonstrate the surface enhanced infrared spectroscopy of one monolayer octadecanthiol (ODT). As know from SEIRS studies using single gold nanowires, the spectral position of the antenna-like resonance in relation to the absorption bands of ODT (2850cm-1 and 2919cm-1) is crucial for both, the lineshape of the molecular vibration and the signal enhancement. In contrast to single nanowires studies, a further increase of the enhanced signals is expected due to the interaction of the electromagnetic fields of the close-by nanowires.

LSPR Coupling and Distribution of Interparticle Distances between Nanoparticles in Hydrogel on Optical Fiber End Face

Directory of Open Access Journals (Sweden)

Harald Ian Muri

2017-11-01

Full Text Available We report on a new localized surface plasmon resonance (LSPR-based optical fiber (OF architecture with a potential in sensor applications. The LSPR-OF system is fabricated by immobilizing gold nanoparticles (GNPs in a hydrogel droplet polymerized on the fiber end face. This design has several advantages over earlier designs. It dramatically increase the number nanoparticles (NP available for sensing, it offers precise control over the NP density, and the NPs are positioned in a true 3D aqueous environment. The OF-hydrogel design is also compatible with low-cost manufacturing. The LSPR-OF platform can measure volumetric changes in a stimuli-responsive hydrogel or measure binding to receptors on the NP surface. It can also be used as a two-parameter sensor by utilizing both effects. We present results from proof-of-concept experiments exploring the properties of LSPR and interparticle distances of the GNP-hydrogel OF design by characterizing the distribution of distances between NPs in the hydrogel, the refractive index of the hydrogel and the LSPR attributes of peak position, amplitude and linewidth for hydrogel deswelling controlled with pH solutions.

Magnetic interactions between nanoparticles

DEFF Research Database (Denmark)

Mørup, Steen; Hansen, Mikkel Fougt; Frandsen, Cathrine

2010-01-01

We present a short overview of the influence of inter-particle interactions on the properties of magnetic nanoparticles. Strong magnetic dipole interactions between ferromagnetic or ferrimagnetic particles, that would be superparamagnetic if isolated, can result in a collective state...... of nanoparticles. This collective state has many similarities to spin-glasses. In samples of aggregated magnetic nanoparticles, exchange interactions are often important and this can also lead to a strong suppression of superparamagnetic relaxation. The temperature dependence of the order parameter in samples...... of strongly interacting hematite nanoparticles or goethite grains is well described by a simple mean field model. Exchange interactions between nanoparticles with different orientations of the easy axes can also result in a rotation of the sub-lattice magnetization directions....

A discrete element study of wet particle-particle interaction during granulation in a spout fluidized bed

NARCIS (Netherlands)

van Buijtenen, M.S.; Deen, N.G.; Heinrich, Stefan; Antonyuk, Sergiy; Kuipers, J.A.M.

2009-01-01

In this article we study the effect of the inter-particle interaction on the bed dynamics, by considering a variable restitution coefficient. The restitution coefficient is varied in time and space depending on the moisture content due to the particle-droplet interaction and evaporation. This study

Equilibrium magnetization and microstructure of the system of superparamagnetic interacting particles: numerical simulation

CERN Document Server

Pshenichnikov, A F

2000-01-01

The Monte Carlo method is used to study the equilibrium magnetization of a 3D system of superparamagnetic particles taking into account the steric and dipole-dipole interparticle interactions. Two types of systems are considered: magnetic fluids and solidified ferrocolloids containing randomly spatially distributed particles with negligible energy of magnetic anisotropy. The results of numerical simulations confirm the universality of Langevin susceptibility as a main dimensionless parameter determining the influence of interparticle interactions on the magnetization of the system for moderate values of the aggregation parameter. The obtained results are in good agreement with theoretical and experimental data. At large values of the aggregation parameter, the clustering of particles in magnetic fluids is observed resulting in a reduction of their magnetization as compared to solidified systems. It is shown that the magnetization of solidified systems can be well described by the modified effective field appr...

Interacting fermions and bosons with definite total momentum

International Nuclear Information System (INIS)

Alon, Ofir E.; Streltsov, Alexej I.; Cederbaum, Lorenz S.

2005-01-01

Any exact eigenstate with a definite momentum of a many-body Hamiltonian can be written as an integral over a symmetry-broken function Φ. For two particles, we exactly express Φ in terms of (single-particle) orbitals for all energy levels and any interparticle interaction. Especially for the ground state, Φ is given by the simple Hartree-Fock and Hartree Ansaetze for fermions and bosons, respectively. Implications for several and many particles as well as a numerical example for interacting bosons are provided

Static and quasi-elastic small angle neutron scattering on biocompatible ionic ferrofluids: magnetic and hydrodynamic interactions

CERN Document Server

Gazeau, F; Dubois, E; Perzynski, R

2003-01-01

We investigate the structure and dynamics of ionic magnetic fluids (MFs), based on ferrite nanoparticles, dispersed at pH approx 7 either in H sub 2 O or in D sub 2 O. Polarized and non-polarized static small angle neutron scattering (SANS) experiments in zero magnetic field allow us to study both the magnetic and the nuclear contributions to the neutron scattering. The magnetic interparticle attraction is probed separately from the global thermodynamic repulsion and compares well to direct magnetic susceptibility measurements. The magnetic interparticle correlation is in these fluid samples independent of the probed spatial scale. In contrast, a spatial dependence of the interparticle correlation is evidenced at large PHI by the nuclear structure factor. A model of magnetic interaction quantitatively explains the under-field anisotropy of the SANS nuclear contribution. In a quasi-elastic neutron spin-echo experiment, we probe the Brownian dynamics of translation of the nanoparticles in the range 1.3 sup<=...

Anisotropy of the magnetoviscous effect in a cobalt ferrofluid with strong interparticle interaction

Energy Technology Data Exchange (ETDEWEB)

Linke, J.M., E-mail: julia.linke@tu-dresden.de; Odenbach, S.

2015-12-15

The anisotropy of the magnetoviscous effect (MVE) of a cobalt ferrofluid has been studied in a slit die viscometer for three orientations of the applied magnetic field: in the direction of the fluid flow (Δη{sub 1}), the velocity gradient (Δη{sub 2}), and the vorticity (Δη{sub 3}). The majority of the cobalt particles in the ferrofluid exhibit a strong dipole–dipole interaction, which corresponds to a weighted interaction parameter of λ{sub w}≈10.6. Thus the particles form extended microstructures inside the fluid which lead to enhanced MVE ratios Δη{sub 2}/Δη{sub 1}>3 and Δη{sub 3}/Δη{sub 1}>0.3 even for strong shearing and weak magnetic fields compared to fluids which contain non-interacting spherical particles with Δη{sub 2}/Δη{sub 1}≈1 and Δη{sub 3}/Δη{sub 1}=0. Furthermore, a non-monotonic increase has been observed in the shear thinning behavior of Δη{sub 2} for weak magnetic fields <10 kA/m, which cannot be explained solely by the magnetization of individual particles and the formation and disintegration of linear particle chains but indicates the presence of heterophase structures. - Highlights: • The magnetoviscous effect in a ferrofluid with strong interaction is anisotropic. • The strongest effects are found in a magnetic field parallel to the shear gradient. • In strong magnetic fields the microstructure of the fluid is stable against shearing. • In weak fields the fluid behavior indicates the presence of heterophase structures.

Equilibrium magnetization and microstructure of the system of superparamagnetic interacting particles: numerical simulation

International Nuclear Information System (INIS)

Pshenichnikov, A.F.; Mekhonoshin, V.V.

2000-01-01

The Monte Carlo method is used to study the equilibrium magnetization of a 3D system of superparamagnetic particles taking into account the steric and dipole-dipole interparticle interactions. Two types of systems are considered: magnetic fluids and solidified ferrocolloids containing randomly spatially distributed particles with negligible energy of magnetic anisotropy. The results of numerical simulations confirm the universality of Langevin susceptibility as a main dimensionless parameter determining the influence of interparticle interactions on the magnetization of the system for moderate values of the aggregation parameter. The obtained results are in good agreement with theoretical and experimental data. At large values of the aggregation parameter, the clustering of particles in magnetic fluids is observed resulting in a reduction of their magnetization as compared to solidified systems. It is shown that the magnetization of solidified systems can be well described by the modified effective field approximation within the whole investigated range of parameters

Interaction between production control and quality control

NARCIS (Netherlands)

Bij, van der J.D.; Ekert, van J.H.W.

1999-01-01

Describes a qualitative study on interaction between systems for production control and quality control within industrial organisations. Production control and quality control interact in a sense. Good performance for one aspect often influences or frustrates the performance of the other. As far as

Role of ligand-ligand vs. core-core interactions in gold nanoclusters.

Science.gov (United States)

Milowska, Karolina Z; Stolarczyk, Jacek K

2016-05-14

The controlled assembly of ligand-coated gold nanoclusters (NCs) into larger structures paves the way for new applications ranging from electronics to nanomedicine. Here, we demonstrate through rigorous density functional theory (DFT) calculations employing novel functionals accounting for van der Waals forces that the ligand-ligand interactions determine whether stable assemblies can be formed. The study of NCs with different core sizes, symmetry forms, ligand lengths, mutual crystal orientations, and in the presence of a solvent suggests that core-to-core van der Waals interactions play a lesser role in the assembly. The dominant interactions originate from combination of steric effects, augmented by ligand bundling on NC facets, and related to them changes in electronic properties induced by neighbouring NCs. We also show that, in contrast to standard colloidal theory approach, DFT correctly reproduces the surprising experimental trends in the strength of the inter-particle interaction observed when varying the length of the ligands. The results underpin the importance of understanding NC interactions in designing gold NCs for a specific function.

Brownian dynamics with hydrodynamic interactions

International Nuclear Information System (INIS)

Ermak, D.L.; McCammon, J.A.

1978-01-01

A method for simulating the Brownian dynamics of N particles with the inclusion of hydrodynamic interactions is described. The particles may also be subject to the usual interparticle or external forces (e.g., electrostatic) which have been included in previous methods for simulating Brownian dynamics of particles in the absence of hydrodynamic interactions. The present method is derived from the Langevin equations for the N particle assembly, and the results are shown to be consistent with the corresponding Fokker--Planck results. Sample calculations on small systems illustrate the importance of including hydrodynamic interactions in Brownian dynamics simulations. The method should be useful for simulation studies of diffusion limited reactions, polymer dynamics, protein folding, particle coagulation, and other phenomena in solution

Interparticle interactions of FePt core and Fe{sub 3}O{sub 4} shell in FePt/Fe{sub 3}O{sub 4} magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Akbari, Hossein, E-mail: Akbari.ph@iauardabil.ac.ir [Department of Physics, Ardabil Branch, Islamic Azad University, Ardabil (Iran, Islamic Republic of); Zeynali, Hossein [Department of Physics, Kashan Branch, Islamic Azad University, Kashan (Iran, Islamic Republic of); Bakhshayeshi, Ali [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

2016-02-22

Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. In FePt/Fe{sub 3}O{sub 4} core/shell system, core thickness is 2 nm and shell thickness varies from zero to 2.5 nm. A theoretical model presented to calculate the shell thickness dependence of Coercivity. Presented model is compared with the results from Stoner–Wohlfarth model to interpret the shell thickness dependence of Coercivity in FePt/Fe{sub 3}O{sub 4} core/shell nanoparticles. There is a difference between the results from Stoner–Wohlfarth model and experimental data when the shell thickness increases. In the presented model, the effects of interparticle exchange and random magneto crystalline anisotropy are added to the previous models of magnetization reversal for core/shell nanostructures in order to achieve a better agreement with experimental data. For magnetic shells in FePt/Fe{sub 3}O{sub 4} core/shell, effective coupling between particles increases with increasing shell thickness which leads to Coercivity destruction for stronger couplings. According to the boundary conditions, in the harder regions with higher exchange stiffness, there is small variation in magnetization and so the magnetization modes become more localized. We discussed both localized and non-localized magnetization modes. For non-zero shell thickness, non-localized modes propagate in the soft phase which effects the quality of particle exchange interactions. - Highlights: • Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. • Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. • A theoretical model presented to calculate the shell thickness dependence of Coercivity. • Magnetic shells increase effective coupling between particles with increasing shell thickness. • Magnetization modes are more localized in the regions with

Understanding Radionuclide Interactions with Layered Materials

Science.gov (United States)

Wang, Y.

2015-12-01

Layered materials play an important role in nuclear waste management and environmental cleanup. Better understanding of radionuclide interactions with those materials is critical for engineering high-performance materials for various applications. This presentation will provide an overview on radionuclide interactions with two general categories of layered materials - cationic clays and anionic clays - from a perspective of nanopore confinement. Nanopores are widely present in layered materials, either as the interlayers or as inter-particle space. Nanopore confinement can significantly modify chemical reactions in those materials. This effect may cause the preferential enrichment of radionuclides in nanopores and therefore directly impact the mobility of the radionuclides. This effect also implies that conventional sorption measurements using disaggregated samples may not represent chemical conditions in actual systems. The control of material structures on ion exchange, surface complexation, and diffusion in layered materials will be systematically examined, and the related modeling approaches will be discussed. This work was performed at Sandia National Laboratories, which is a multiprogram laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the DOE under contract DE-AC04-94AL8500.

Classical many-body theory with retarded interactions: Dynamical irreversibility and determinism without probabilities

Energy Technology Data Exchange (ETDEWEB)

Zakharov, A.Yu., E-mail: Anatoly.Zakharov@novsu.ru; Zakharov, M.A., E-mail: ma_zakharov@list.ru

2016-01-28

The exact equations of motion for microscopic density of classical many-body system with account of inter-particle retarded interactions is derived. It is shown that interactions retardation leads to irreversible behavior of many-body systems. - Highlights: • A new form of equation of motion of classical many-body system is proposed. • Interactions retardation as one of the mechanisms of many-body system irreversibility. • Irreversibility and determinism without probabilities. • The possible way to microscopic foundation of thermodynamics.

The influence of conductive additives and inter-particle voids in carbon EDLC electrodes

Energy Technology Data Exchange (ETDEWEB)

Pandolfo, A.G.; Wilson, G.J.; Huynh, T.D.; Hollenkamp, A.F. [CSIRO - Energy Technology, Bayview Avenue, Clayton, Vic 3168 (Australia)

2010-10-15

Through the interpretation of porosity and intrusion data, and correlation to the electrochemical response, this study has confirmed that are not only carbon blacks (CBs) very effective in improving the electrical connectivity of a carbon electrode coating, but they also significantly modify the porosity of the electrode coating and thereby also influence ionic diffusion. CBs are more effective conductive fillers than graphites in EDLC electrodes. The highly branched structure of CBs allows multiple electrical contact points and results in a lower electrode electronic resistance. CBs can decrease inter-particle porosity (both volume and size) and introduce additional porosity that is characteristic of the type of carbon employed. It is observed that electrode coatings prepared from a carbon slurry have a highly macroporous structure and that electrolyte accessibility to individual activated carbon particles is unlikely to be the limiting factor to accessing capacitance. Electrochemical testing has confirmed the strong relationship between bulk electrode resistance and the accessibility of capacitance at different rates. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Ray-theory approach to electrical-double-layer interactions.

Science.gov (United States)

Schnitzer, Ory

2015-02-01

A novel approach is presented for analyzing the double-layer interaction force between charged particles in electrolyte solution, in the limit where the Debye length is small compared with both interparticle separation and particle size. The method, developed here for two planar convex particles of otherwise arbitrary geometry, yields a simple asymptotic approximation limited to neither small zeta potentials nor the "close-proximity" assumption underlying Derjaguin's approximation. Starting from the nonlinear Poisson-Boltzmann formulation, boundary-layer solutions describing the thin diffuse-charge layers are asymptotically matched to a WKBJ expansion valid in the bulk, where the potential is exponentially small. The latter expansion describes the bulk potential as superposed contributions conveyed by "rays" emanating normally from the boundary layers. On a special curve generated by the centers of all circles maximally inscribed between the two particles, the bulk stress-associated with the ray contributions interacting nonlinearly-decays exponentially with distance from the center of the smallest of these circles. The force is then obtained by integrating the traction along this curve using Laplace's method. We illustrate the usefulness of our theory by comparing it, alongside Derjaguin's approximation, with numerical simulations in the case of two parallel cylinders at low potentials. By combining our result and Derjaguin's approximation, the interaction force is provided at arbitrary interparticle separations. Our theory can be generalized to arbitrary three-dimensional geometries, nonideal electrolyte models, and other physical scenarios where exponentially decaying fields give rise to forces.

Micro-rheology and interparticle interactions in aerosols probed with optical tweezers

Science.gov (United States)

Reid, Jonathan P.; Power, Rory M.; Cai, Chen; Simpson, Stephen H.

2014-09-01

Using optical tweezers for micro-rheological investigations of a surrounding fluid has been routinely demonstrated. In this work, we will demonstrate that rheological measurements of the bulk and surface properties of aerosol particles can be made directly using optical tweezers, providing important insights into the phase behavior of materials in confined environments and the rate of molecular diffusion in viscous phases. The use of holographic optical tweezers to manipulate aerosol particles has become standard practice in recent years, providing an invaluable tool to investigate particle dynamics, including evaporation/ condensation kinetics, chemical aging and phase transformation. When combined with non-linear Raman spectroscopy, the size and refractive index of a particle can be determined with unprecedented accuracy viscosity and surface tension of particles can be measured directly in the under-damped regime at low viscosity. In the over-damped regime, we will show that viscosity measurements can extend close to the glass transition, allowing measurements over an impressive dynamic range of 12 orders of magnitude in relaxation timescale and viscosity. Indeed, prior to the coalescence event, we will show how the Brownian trajectories of trapped particles can yield important and unique insights into the interactions of aerosol particles.

Controlling the interparticle distance in a 2D molecule-nanoparticle network

Energy Technology Data Exchange (ETDEWEB)

Guedon, C M; Zonneveld, J; Van der Molen, S J [Kamerlingh Onnes Laboratorium, Leiden University, PO Box 9504, 2300 RA Leiden (Netherlands); Valkenier, H; Hummelen, J C [Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)

2011-03-25

Mechanically controllable break junctions allow for an impressive level of control over the distance between two electrodes, but lack stability at room temperature. On the other hand, two-dimensional (2D) networks of nanoparticles bridged by molecules form a stable device structure for investigating molecular conductance properties. Here, we combine both techniques to create a robust platform for molecular charge transport with control over the inter-electrode distance on the picometer scale. The resistance change due to bending of our structures is dependent on the molecular species present between the nanoparticles.

Controlling the interparticle distance in a 2D molecule-nanoparticle network

International Nuclear Information System (INIS)

Guedon, C M; Zonneveld, J; Van der Molen, S J; Valkenier, H; Hummelen, J C

2011-01-01

Mechanically controllable break junctions allow for an impressive level of control over the distance between two electrodes, but lack stability at room temperature. On the other hand, two-dimensional (2D) networks of nanoparticles bridged by molecules form a stable device structure for investigating molecular conductance properties. Here, we combine both techniques to create a robust platform for molecular charge transport with control over the inter-electrode distance on the picometer scale. The resistance change due to bending of our structures is dependent on the molecular species present between the nanoparticles.

Experimental comparison of particle interaction measurement techniques using optical traps

International Nuclear Information System (INIS)

Koehler, Timothy P.; Grillet, Anne Mary; Brotherton, Christopher M.; Molecke, Ryan A.

2008-01-01

Optical tweezers has become a powerful and common tool for sensitive determination of electrostatic interactions between colloidal particles. Recently, two techniques, 'blinking' tweezers and direct force measurements, have become increasingly prevalent in investigations of inter-particle potentials. The 'blinking' tweezers method acquires physical statistics of particle trajectories to determine drift velocities, diffusion coefficients, and ultimately colloidal forces as a function of the center-center separation of two particles. Direct force measurements monitor the position of a particle relative to the center of an optical trap as the separation distance between two continuously trapped particles is gradually decreased. As the particles near each other, the displacement from the trap center for each particle increases proportional to the inter-particle force. Although commonly employed in the investigation of interactions of colloidal particles, there exists no direct comparison of these experimental methods in the literature. In this study, an experimental apparatus was developed capable of performing both methods and is used to quantify electrostatic potentials between particles in several particle/solvent systems. Comparisons are drawn between the experiments conducted using the two measurement techniques, theory, and existing literature. Forces are quantified on the femto-Newton scale and results agree well with literature values

A study of inter-particle bonds in dry bauxite waste resulting in atmospheric aerosols

Science.gov (United States)

Wagh, Arun S.; Thompson, Bentley

1988-02-01

Bauxite and Alumina production are one of the main activities of several third world countries such as Jamaica, Brazil, India, Guinea, eastern European countries such as Hungary and Rumania and advanced countries such as Australia, West Germany, Japan and the United States. The mining operations lead to dust pollution, but the refining of bauxite to alumina yield large amounts of highly caustic sludge waste, called "Red Mud". Millions of tons of the waste produced in every country are stored in containment dams or natural valleys. This leads to ground water pollution, destruction of plant and bird life and is hazardous to human settlement in earthquake prone regions like Jamaica. As a result several companies have been looking into dry mud stacking which involves thickening the mud in the refining plants and sprying it on the slopes to sun dry it. Typically it involves a drying field of about two hundred acres, which could act as a potential source of caustic dust. In Jamaica one company has started disposing of the mud in this way. The aerosol formation from such areas depends mainly on the integrity of the top dry layers. Presently this is done by studying the approximate parameters such as the friability of the mud. However, following the recent advances in powder technology it has been possible for us to develop an instrument to study the average interparticle forces between the red mud particles. The instrument is based on the principle of a tensometer and a split cell is used to load specimens. A load cell is used to measure the force and a chart recorder is used for plotting separation and the force. The present study reports elemental composition of the dust and its health hazards. It also reports the physical measurement of the average interparticle force as a function of their separation in the Jamaican mud. The effect of ultraviolet radiation on the strength of the material is studied to see the effect of sun-drying of the waste. The five-fold increase

Self-Supporting Nanodiamond Gels: Elucidating Colloidal Interactions Through Rheology_

Science.gov (United States)

Adhikari, Prajesh; Tripathi, Anurodh; Vogel, Nancy A.; Rojas, Orlando J.; Raghavan, Sriunivasa R.; Khan, Saad A.

This work investigates the colloidal interactions and rheological behavior of nanodiamond (ND) dispersions. While ND represents a promising class of nanofiller due to its high surface area, superior mechanical strength, tailorable surface functionality and biocompatibility, much remains unknown about the behavior of ND dispersions. We hypothesize that controlling interactions in ND dispersions will lead to highly functional systems with tunable modulus and shear response. Steady and dynamic rheology techniques are thus employed to systematically investigate nanodiamonds dispersed in model polar and non-polar media. We find that low concentrations of ND form gels almost instantaneously in a non-polar media. In contrast, ND's in polar media show a time-dependent behavior with the modulus increasing with time. We attribute the difference in behavior to variations in inter-particle interactions as well as the interaction of the ND with the media. Large steady and oscillatory strains are applied to ND colloidal gels to investigate the role of shear in gel microstructure breakdown and recovery. For colloidal gels in non-polar medium, the incomplete recovery of elastic modulus at high strain amplitudes indicates dominance of particle-particle interactions; however, in polar media the complete recovery of elastic modulus even at high strain amplitudes indicates dominance of particle-solvent interactions. These results taken together provide a platform to develop self-supporting gels with tunable properties in terms of ND concentration, and solvent type.

The capillary interaction between two vertical cylinders

KAUST Repository

Cooray, Himantha

2012-06-27

Particles floating at the surface of a liquid generally deform the liquid surface. Minimizing the energetic cost of these deformations results in an inter-particle force which is usually attractive and causes floating particles to aggregate and form surface clusters. Here we present a numerical method for determining the three-dimensional meniscus around a pair of vertical circular cylinders. This involves the numerical solution of the fully nonlinear Laplace-Young equation using a mesh-free finite difference method. Inter-particle force-separation curves for pairs of vertical cylinders are then calculated for different radii and contact angles. These results are compared with previously published asymptotic and experimental results. For large inter-particle separations and conditions such that the meniscus slope remains small everywhere, good agreement is found between all three approaches (numerical, asymptotic and experimental). This is as expected since the asymptotic results were derived using the linearized Laplace-Young equation. For steeper menisci and smaller inter-particle separations, however, the numerical simulation resolves discrepancies between existing asymptotic and experimental results, demonstrating that this discrepancy was due to the nonlinearity of the Laplace-Young equation. © 2012 IOP Publishing Ltd.

Relativistic approach to the near-threshold phenomena in the nucleon-antinucleon interactions

International Nuclear Information System (INIS)

Shapiro, I.S.; Smirnov, A.V.

1997-01-01

It is shown that the strongest (∝r -3 ) singularities at small interparticle distances, arising from the spin-tensor forces in the standard nonrelativistic one-boson-exchange (OBE) potentials, disappear in the relativistic treatment of the NN- and NN-interactions. The partial wave analysis is performed in the framework of a relativistic OBE quasipotential model, and the results are compared with those obtained in the nonrelativistic approximation. (orig.)

The effect of grinding on magnetic properties of agglomereted MnFe2O4 nanoparticles

International Nuclear Information System (INIS)

Aslibeiki, B.; Kameli, P.; Salamati, H.

2012-01-01

The effects of grinding on interparticle magnetic interactions for an ensemble of agglomerated MnFe 2 O 4 nanoparticles have been studied. Structural analyses showed that by grinding the samples, a small variation in size of crystallites and lattice strain will occur. ac Magnetic susceptibility measurements under different conditions and spin dynamics analysis suggest that freezing temperature is frequency dependent and it is in good agreement with critical slowing down model. This is an indication that these nanoparticles have superspin glass behavior. The estimated zυ and τ 0 parameters using critical slowing down model show that by increasing the grinding time the interaction between nanoparticles decreases. ac Susceptibility measurements in cooling and heating process show a thermal hysteresis. The thermal hysteresis decreased by increasing the grinding time. Also, the thermal hysteresis is frequency dependent and it increased as frequency decreased. These results showed that interparticle interactions such as dipole-dipole and exchange interactions between nanoparticles become weaker by grinding. - Highlights: → We studied the effects of grinding on interparticle interactions of MnFe 2 O 4 nanoparticles. → Critical slowing model used to estimate the interparticle interaction strength. → The results showed interparticle interactions become weaker by grinding. → Ac Susceptibility shows the irreversibility of spins decreased by grinding.

Self-Assembly of DNA-Coated Particles: Experiment, Simulation and Theory

Science.gov (United States)

Song, Minseok

The bottom-up assembly of material architectures with tunable complexity, function, composition, and structure is a long sought goal in rational materials design. One promising approach aims to harnesses the programmability and specificity of DNA hybridization in order to direct the assembly of oligonucleotide-functionalized nano- and micro-particles by tailoring, in part, interparticle interactions. DNA-programmable assembly into three-dimensionally ordered structures has attracted extensive research interest owing to emergent applications in photonics, plasmonics and catalysis and potentially many other areas. Progress on the rational design of DNA-mediated interactions to create useful two-dimensional structures (e.g., structured films), on the other hand, has been rather slow. In this thesis, we establish strategies to engineer a diversity of 2D crystalline arrangements by designing and exploiting DNA-programmable interparticle interactions. We employ a combination of simulation, theory and experiments to predict and confirm accessibility of 2D structural diversity in an effort to establish a rational approach to 2D DNA-mediated particle assembly. We start with the experimental realization of 2D DNA-mediated assembly by decorating micron-sized silica particles with covalently attached single-stranded DNA through a two-step reaction. Subsequently, we elucidate sensitivity and ultimate controllability of DNA-mediated assembly---specifically the melting transition from dispersed singlet particles to aggregated or assembled structures---through control of the concentration of commonly employed nonionic surfactants. We relate the observed tunability to an apparent coupling with the critical micelle temperature in these systems. Also, both square and hexagonal 2D ordered particle arrangements are shown to evolve from disordered aggregates under appropriate annealing conditions defined based upon pre-established melting profiles. Subsequently, the controlled mixing of

Impacts of Coulomb Interactions on the Magnetic Responses of Excitonic Complexes in Single Semiconductor Nanostructures

Directory of Open Access Journals (Sweden)

Fu Ying-Jhe

2010-01-01

Full Text Available Abstract We report on the diamagnetic responses of different exciton complexes in single InAs/GaAs self-assembled quantum dots (QDs and quantum rings (QRs. For QDs, the imbalanced magnetic responses of inter-particle Coulomb interactions play a crucial role in the diamagnetic shifts of excitons (X, biexcitons (XX, and positive trions (X−. For negative trions (X− in QDs, anomalous magnetic responses are observed, which cannot be described by the conventional quadratic energy shift with the magnetic field. The anomalous behavior is attributed to the apparent change in the electron wave function extent after photon emission due to the strong Coulomb attraction by the hole in its initial state. In QRs, the diamagnetic responses of X and XX also show different behaviors. Unlike QDs, the diamagnetic shift of XX in QRs is considerably larger than that of X. The inherent structural asymmetry combined with the inter-particle Coulomb interactions makes the wave function distribution of XX very different from that of X in QRs. Our results suggest that the phase coherence of XX in QRs may survive from the wave function localization due to the structural asymmetry or imperfections.

Interacting composite fermions

DEFF Research Database (Denmark)

nrc762, nrc762

2016-01-01

Numerical studies by Wójs, Yi, and Quinn have suggested that an unconventional fractional quantum Hall effect is plausible at filling factors ν=1/3 and 1/5, provided the interparticle interaction has an unusual form for which the energy of two fermions in the relative angular momentum three channel...... as fractional quantum Hall effect of electrons at ν=4/11, 4/13, 5/13, and 5/17. I investigate in this article the nature of the fractional quantum Hall states at ν=4/5, 5/7, 6/17, and 6/7, which correspond to composite fermions at ν∗=4/3, 5/3, and 6/5, and find that all these fractional quantum Hall states...... are conventional. The underlying reason is that the interaction between composite fermions depends substantially on both the number and the direction of the vortices attached to the electrons. I also study in detail the states with different spin polarizations at 6/17 and 6/7 and predict the critical Zeeman...

Hydrodynamic interactions of two nearly touching Brownian spheres in a stiff potential: Effect of fluid inertia

International Nuclear Information System (INIS)

Radiom, Milad; Ducker, William; Robbins, Brian; Paul, Mark

2015-01-01

The hydrodynamic interaction of two closely spaced micron-scale spheres undergoing Brownian motion was measured as a function of their separation. Each sphere was attached to the distal end of a different atomic force microscopy cantilever, placing each sphere in a stiff one-dimensional potential (0.08 Nm −1 ) with a high frequency of thermal oscillations (resonance at 4 kHz). As a result, the sphere’s inertial and restoring forces were significant when compared to the force due to viscous drag. We explored interparticle gap regions where there was overlap between the two Stokes layers surrounding each sphere. Our experimental measurements are the first of their kind in this parameter regime. The high frequency of oscillation of the spheres means that an analysis of the fluid dynamics would include the effects of fluid inertia, as described by the unsteady Stokes equation. However, we find that, for interparticle separations less than twice the thickness of the wake of the unsteady viscous boundary layer (the Stokes layer), the hydrodynamic interaction between the Brownian particles is well-approximated by analytical expressions that neglect the inertia of the fluid. This is because elevated frictional forces at narrow gaps dominate fluid inertial effects. The significance is that interparticle collisions and concentrated suspensions at this condition can be modeled without the need to incorporate fluid inertia. We suggest a way to predict when fluid inertial effects can be ignored by including the gap-width dependence into the frequency number. We also show that low frequency number analysis can be used to determine the microrheology of mixtures at interfaces

Metastability and coherence of repulsive polarons in a strongly interacting Fermi mixture

DEFF Research Database (Denmark)

Kohstall, Cristoph; Zaccanti, Mattheo; Jag, Matthias

2012-01-01

show that a well-defined quasiparticle exists for strongly repulsive interactions. We measure the energy and the lifetime of this ‘repulsive polaron’9, 12, 13, and probe its coherence properties by measuring the quasiparticle residue. The results are well described by a theoretical approach that takes...... into account the finite effective range of the interaction in our system. We find that when the effective range is of the order of the interparticle spacing, there is a substantial increase in the lifetime of the quasiparticles. The existence of such a long-lived, metastable many-body state offers intriguing...

Control of crack pattern using memory effect of paste

International Nuclear Information System (INIS)

Nakahara, Akio; Shinohara, Yuu; Matsuo, Yousuke

2011-01-01

A densely packed colloidal suspension, called as a paste, remembers the direction of external mechanical fields, such as flow and vibration. When the pastes are dried, memories in pastes are visualized as macroscopically anisotropic crack patterns, such as lamellar, radial, ring and spiral. Here, we experimentally investigate how pastes remember such experiences by using paste with different size distribution of colloidal particles. We find that a paste with smaller particles have a better memory, in the sense it remembers external mechanical fields at smaller solid volume fraction, which implies that interparticle forces between colloidal particles play an important role in memory effects, causing a quantitative change in the phase diagram for the same material. This result supports the hypothesis that memories in pastes are maintained as microscopically anisotropic network structure of colloidal particles, connected via interparticle forces between colloidal particles, such as van der Waals interaction.

Magnetic dynamics of weakly and strongly interacting hematite nanoparticles

DEFF Research Database (Denmark)

Hansen, Mikkel Fougt; Bender Koch, Christian; Mørup, Steen

2000-01-01

The magnetic dynamics of two differently treated samples of hematite nanoparticles from the same batch with a particle size of about 20 nm have been studied by Mossbauer spectroscopy. The dynamics of the first sample, in which the particles are coated and dispersed in water, is in accordance with...... down by interparticle interactions and a magnetically split spectrum is retained at room temperature. The temperature variation or the magnetic hyperfine field, corresponding to different quantiles in the hyperfine field distribution, can be consistently described by a mean field model...... for "superferromagnetism" in which the magnetic anisotropy is included. The coupling between the particles is due to exchange interactions and the interaction strength can be accounted for by just a few exchange bridges between surface atoms in neighboring crystallites....

Radio-Frequency-Controlled Cold Collisions and Universal Properties of Unitary Bose Gases

Science.gov (United States)

Ding, Yijue

This thesis investigates two topics: ultracold atomic collisions in a radio-frequency field and universal properties of a degenerate unitary Bose gas. One interesting point of the unitary Bose gas is that the system has only one length scale, that is, the average interparticle distance. This single parameter determines all properties of the gas, which is called the universality of the system. We first introduce a renormalized contact interaction to extend the validity of the zero-range interaction to large scattering lengths. Then this renormalized interaction is applied to many-body theories to determined those universal relations of the system. From the few-body perspective, we discuss the scattering between atoms in a single-color radio-frequency field. Our motivation is proposing the radio-frequency field as an effective tool to control interactions between cold atoms. Such a technique may be useful in future experiments such as creating phase transitions in spinor condensates. We also discuss the formation of ultracold molecules using radio-freqency fields from a time-dependent approach.

Analysis of pattern formation in systems with competing range interactions

International Nuclear Information System (INIS)

Zhao, H J; Misko, V R; Peeters, F M

2012-01-01

We analyzed pattern formation and identified various morphologies in a system of particles interacting through a non-monotonic potential with a competing range interaction characterized by a repulsive core (r c ) and an attractive tail (r > r c ), using molecular-dynamics simulations. Depending on parameters, the interaction potential models the inter-particle interaction in various physical systems ranging from atoms, molecules and colloids to vortices in low κ type-II superconductors and in recently discovered ‘type-1.5’ superconductors. We constructed a ‘morphology diagram’ in the plane ‘critical radius r c -density n’ and proposed a new approach to characterizing the different types of patterns. Namely, we elaborated a set of quantitative criteria in order to identify the different pattern types, using the radial distribution function (RDF), the local density function and the occupation factor. (paper)

Interactions controlled evolution of complex magnetoresistance in as-deposited Ag100−xCox nanogranular films with perpendicular magnetic anisotropy

International Nuclear Information System (INIS)

Kumar, Dinesh; Chaudhary, Sujeet; Pandya, Dinesh K.

2015-01-01

Evolution of a complex magnetoresistance and dc-magnetization behavior of as-deposited co-sputtered Ag 100−x Co x films with the variation of cobalt concentration ‘x’ from 25.2 to 45.1 at% is presented. At 20 K, a transition from normal to complex magnetoresistance behavior, in conjunction with magnetic force microscopy evidence of the existence of a magnetic microstructure resulting in perpendicular magnetic anisotropy (PMA) is observed for x=32.6 cobalt concentration film. The dc-magnetization studies provide additional support to the presence of PMA in film that gets reduced with the increase of cobalt concentration. The complex magnetoresistance (MR) behavior also decreases with the increase of ‘x’. The room temperature MR, coercivity behavior and remanence to saturation magnetization ratio indicate the presence of direct ferromagnetic interactions due to the presence of ferromagnetic particles for x≥32.6 films. The observed complex MR behavior and presence of PMA are interpreted in terms of manifestation of the transition of interparticle magnetic interaction nature from dipolar to direct ferromagnetic. - Highlights: • Complex MR with perpendicular magnetic anisotropy (PMA) is observed. • MFM evidenced the presence of PMA. • Complex MR and PMA decreases with the increase of cobalt concentration. • Observed results are correlated with the nature of magnetic interactions

Automatic Control of Contextual Interaction Integrated with Affection and Architectural Attentional Control

Directory of Open Access Journals (Sweden)

Yanrong Jiang

2013-03-01

Full Text Available It is still a challenge for robots to interact with complex environments in a smooth and natural manner. The robot should be aware of its surroundings and inner status to make decisions accordingly and appropriately. Contexts benefit the interaction a lot, such as avoiding frequent interruptions (e.g., the explicit inputting requests and thus are essential for interaction. Other challenges, such as shifting attentional focus to a more important stimulus, etc., are also crucial in interaction control. This paper presents a hybrid automatic control approach for interaction, as well as its integration, with these multiple important factors, aiming at performing natural, human-like interactions in robots. In particular, a novel approach of architectural attentional control, based on affection is presented, which attempts to shift the attentional focus in a natural manner. Context-aware computing is combined with interaction to endow the robot with proactive abilities. The long-term interaction control approaches are described. Emotion and personality are introduced into the interaction and their influence mechanism on interaction is explored. We implemented the proposal in an interactive head robot (IHR and the experimental results indicate the effectiveness.

Tunable interactions between paramagnetic colloidal particles driven in a modulated ratchet potential.

Science.gov (United States)

Straube, Arthur V; Tierno, Pietro

2014-06-14

We study experimentally and theoretically the interactions between paramagnetic particles dispersed in water and driven above the surface of a stripe patterned magnetic garnet film. An external rotating magnetic field modulates the stray field of the garnet film and generates a translating potential landscape which induces directed particle motion. By varying the ellipticity of the rotating field, we tune the inter-particle interactions from net repulsive to net attractive. For attractive interactions, we show that pairs of particles can approach each other and form stable doublets which afterwards travel along the modulated landscape at a constant mean speed. We measure the strength of the attractive force between the moving particles and propose an analytically tractable model that explains the observations and is in quantitative agreement with experiment.

Measuring interactivity on tobacco control websites.

Science.gov (United States)

Freeman, Becky; Chapman, Simon

2012-08-01

With the increased reach of Web 2.0, Internet users expect webpages to be interactive. No studies have been conducted to assess whether tobacco control-relevant sites have implemented these features. The authors conducted an analysis of an international sample of tobacco control-relevant websites to determine their level of interactivity. The sample included 68 unique websites selected from Google searches in 5 countries, on each country's Google site, using the term smoking. The 68 sites were analyzed for 10 categories of interactive tools. The most common type of interactive content found on 46 (68%) of sites was for multimedia featuring content that was not primarily text based, such as photo galleries, videos, or podcasts. Only 11 (16%) websites-outside of media sites-allowed people to interact and engage with the site owners and other users by allowing posting comments on content and/or hosting forums/discussions. Linkages to social networking sites were low: 17 pages (25%) linked to Twitter, 15 (22%) to Facebook, and 11 (16%) to YouTube. Interactivity and connectedness to online social media appears to still be in its infancy among tobacco control-relevant sites.

Interactivity in automatic control: foundations and experiences

OpenAIRE

Dormido Bencomo, Sebastián; Guzmán Sánchez, José Luis; Costa Castelló, Ramon; Berenguel, M

2012-01-01

The first part of this paper presents the concepts of interactivity and visualization and its essential role in learning the fundamentals and techniques of automatic control. More than 10 years experience of the authors in the development and design of interactive tools dedicated to the study of automatic control concepts are also exposed. The second part of the paper summarizes the main features of the “Automatic Control with Interactive Tools” text that has been recently published by Pea...

Correlated wave functions for three-particle systems with Coulomb interaction - The muonic helium atom

Science.gov (United States)

Huang, K.-N.

1977-01-01

A computational procedure for calculating correlated wave functions is proposed for three-particle systems interacting through Coulomb forces. Calculations are carried out for the muonic helium atom. Variational wave functions which explicitly contain interparticle coordinates are presented for the ground and excited states. General Hylleraas-type trial functions are used as the basis for the correlated wave functions. Excited-state energies of the muonic helium atom computed from 1- and 35-term wave functions are listed for four states.

Effect of long-range repulsive Coulomb interactions on packing structure of adhesive particles.

Science.gov (United States)

Chen, Sheng; Li, Shuiqing; Liu, Wenwei; Makse, Hernán A

2016-02-14

The packing of charged micron-sized particles is investigated using discrete element simulations based on adhesive contact dynamic model. The formation process and the final obtained structures of ballistic packings are studied to show the effect of interparticle Coulomb force. It is found that increasing the charge on particles causes a remarkable decrease of the packing volume fraction ϕ and the average coordination number 〈Z〉, indicating a looser and chainlike structure. Force-scaling analysis shows that the long-range Coulomb interaction changes packing structures through its influence on particle inertia before they are bonded into the force networks. Once contact networks are formed, the expansion effect caused by repulsive Coulomb forces are dominated by short-range adhesion. Based on abundant results from simulations, a dimensionless adhesion parameter Ad*, which combines the effects of the particle inertia, the short-range adhesion and the long-range Coulomb interaction, is proposed and successfully scales the packing results for micron-sized particles within the latest derived adhesive loose packing (ALP) regime. The structural properties of our packings follow well the recent theoretical prediction which is described by an ensemble approach based on a coarse-grained volume function, indicating some kind of universality in the low packing density regime of the phase diagram regardless of adhesion or particle charge. Based on the comprehensive consideration of the complicated inter-particle interactions, our findings provide insight into the roles of short-range adhesion and repulsive Coulomb force during packing formation and should be useful for further design of packings.

Programming the Assembly of Unnatural Materials with Nucleic Acids

Science.gov (United States)

Mirkin, Chad

Nature directs the assembly of enormously complex and highly functional materials through an encoded class of biomolecules, nucleic acids. The establishment of a similarly programmable code for the construction of synthetic, unnatural materials would allow researchers to impart functionality by precisely positioning all material components. Although it is exceedingly difficult to control the complex interactions between atomic and molecular species in such a manner, interactions between nanoscale components can be directed through the ligands attached to their surface. Our group has shown that nucleic acids can be used as highly programmable surface ligands to control the spacing and symmetry of nanoparticle building blocks in structurally sophisticated and functional materials. These nucleic acids function as programmable ``bonds'' between nanoparticle ``atoms,'' analogous to a nanoscale genetic code for assembling materials. The sequence and length tunability of nucleic acid bonds has allowed us to define a powerful set of design rules for the construction of nanoparticle superlattices with more than 30 unique lattice symmetries, tunable defect structures and interparticle spacings, and several well-defined crystal habits. Further, the nature of the nucleic acid bond enables an additional level of structural control: temporal regulation of dynamic material response to external biomolecular and chemical stimuli. This control allows for the reversible transformation between thermodynamic states with different crystal symmetries, particle stoichiometries, thermal stabilities, and interparticle spacings on demand. Notably, our unique genetic approach affords functional nanoparticle architectures that, among many other applications, can be used to systematically explore and manipulate optoelectronic material properties, such as tunable interparticle plasmonic interactions, microstructure-directed energy emission, and coupled plasmonic and photonic modes.

Periodic and quasiperiodic revivals in periodically driven interacting quantum systems

Science.gov (United States)

Luitz, David J.; Lazarides, Achilleas; Bar Lev, Yevgeny

2018-01-01

Recently it has been shown that interparticle interactions generically destroy dynamical localization in periodically driven systems, resulting in diffusive transport and heating. In this Rapid Communication we rigorously construct a family of interacting driven systems which are dynamically localized and effectively decoupled from the external driving potential. We show that these systems exhibit tunable periodic or quasiperiodic revivals of the many-body wave function and thus of all physical observables. By numerically examining spinless fermions on a one-dimensional lattice we show that the analytically obtained revivals of such systems remain stable for finite systems with open boundary conditions while having a finite lifetime in the presence of static spatial disorder. We find this lifetime to be inversely proportional to the disorder strength.

Applying interactive control to waste processing operations

International Nuclear Information System (INIS)

Grasz, E.L.; Merrill, R.D.; Couture, S.A.

1992-08-01

At present waste and residue processing includes steps that require human interaction. The risk of exposure to unknown hazardous materials and the potential for radiation contamination motivates the desire to remove operators from these processes. Technologies that facilitate this include glove box robotics, modular systems for remote and automated servicing, and interactive controls that minimize human intervention. LLNL is developing an automated system which is designed to supplant the operator for glove box tasks, thus protecting the operator from the risk of radiation exposure and minimizing operator-associated waste. Although most of the processing can be automated with minimal human interaction, there are some tasks where intelligent intervention is both desirable and necessary to adapt to Enexpected circumstances and events. These activities require that the operator interact with the process using a remote manipulator which provides or reflects a natural feel to the operator. The remote manipulation system which was developed incorporates sensor fusion and interactive control, and provides the operator with an effective means of controlling the robot in a potentially unknown environment. This paper describes recent accomplishments in technology development and integration, and outlines the future goals of Lawrence Livermore National Laboratory for achieving this integrated interactive control capability

Interaction forces between nanoparticles in Lennard-Jones (L-J) solvents

International Nuclear Information System (INIS)

Sinha, Indrajit; Mukherjee, Ashim K

2014-01-01

Molecular simulations, such as Monte Carlo (MC) and molecular dynamics (MD) have been recently used for understanding the forces between colloidal nanoparticles that determine the dispersion and stability of nanoparticle suspensions. Herein we review the current status of research in the area of nanoparticles immersed in L-J solvents. The first study by Shinto et al. used large smooth spheres to depict nanoparticles in L-J and soft sphere solvents. The nanoparticles were held fixed at a particular interparticle distance and only the solvents were allowed to equilibrate. Both Van-der-waals and solvation forces were computed at different but fixed interparticle separation. Later Qin and Fitchthorn improved on this model by considering the nanoparticles as collection of molecules, thus taking into the account the effect of surface roughness of nanoparticles. Although the inter particle distance was fixed, the rotation of such nanoparticles with respect to each other was also investigated. Recently, in keeping with the experimental situation, we modified this model by allowing the nanoparticles to move and rotate freely. Solvophilic, neutral and solvophobic interactions between the solvent atoms and those that make up the nanoparticles were modelled. While neutral and solvophobic nanoparticles coalesce even at intermediate distances, solvophilic nanoparticles are more stable in solution due to the formation of a solvent shield

Dilution effects on combined magnetic and electric dipole interactions: A study of ferromagnetic cobalt nanoparticles with tuneable interactions

Science.gov (United States)

Hod, M.; Dobroserdova, A.; Samin, S.; Dobbrow, C.; Schmidt, A. M.; Gottlieb, M.; Kantorovich, S.

2017-08-01

Improved understanding of complex interactions between nanoparticles will facilitate the control over the ensuing self-assembled structures. In this work, we consider the dynamic changes occurring upon dilution in the self-assembly of a system of ferromagnetic cobalt nanoparticles that combine magnetic, electric, and steric interactions. The systems examined here vary in the strength of the magnetic dipole interactions and the amount of point charges per particle. Scattering techniques are employed for the characterization of the self-assembly aggregates, and zeta-potential measurements are employed for the estimation of surface charges. Our experiments show that for particles with relatively small initial number of surface electric dipoles, an increase in particle concentration results in an increase in diffusion coefficients; whereas for particles with relatively high number of surface dipoles, no effect is observed upon concentration changes. We attribute these changes to a shift in the adsorption/desorption equilibrium of the tri-n-octylphosphine oxide (TOPO) molecules on the particle surface. We put forward an explanation, based on the combination of two theoretical models. One predicts that the growing concentration of electric dipoles, stemming from the addition of tri-n-octylphosphine oxide (TOPO) as co-surfactant during particle synthesis, on the surface of the particles results in the overall repulsive interaction. Secondly, using density functional theory, we explain that the observed behaviour of the diffusion coefficient can be treated as a result of the concentration dependent nanoparticle self-assembly: additional repulsion leads to the reduction in self-assembled aggregate size despite the shorter average interparticle distances, and as such provides the growth of the diffusion coefficient.

Interparticle interaction and transport processes in dense semiclassical plasmas

International Nuclear Information System (INIS)

Baimbetov, F.B.; Giniyatova, Sh.G.

2005-01-01

On the basis of the density response formalism an expression for the pseudopotential of dense semiclassical plasma, which takes account of quantum-mechanical effects, local field corrections, and electronic screening effects is obtained. The static structure factors taking into account both local fields and quantum-mechanical effects are calculated. An electrical conductivity, thermal conductivity, and viscosity of dense semiclassical plasma are studied

Key role of asymmetric interactions in low-dimensional heat transport

International Nuclear Information System (INIS)

Chen, Shunda; Zhang, Yong; Wang, Jiao; Zhao, Hong

2016-01-01

We study the heat current autocorrelation function (HCAF) in one-dimensional, momentum-conserving lattices. In particular, we explore if there is any link between the decaying characteristics of the HCAF and asymmetric interparticle interactions. The Lennard-Jones model is investigated intensively in view of its significance to applications. It is found that, in the time range accessible to numerical simulations, the HCAF decays faster than power-law manners, and in some cases it decays even exponentially. Following the Green–Kubo formula, fast decay of the HCAF implies convergence of the heat conductivity, which is also corroborated by simulations. In addition, with a comparison to the Fermi–Pasta–Ulam-β model of symmetric interactions, the HCAF of the Fermi–Pasta–Ulam-α–β model of asymmetric interactions is also investigated. The results of all these studies lead to that, in certain ranges of parameters, fast decaying of the HCAF can be observed and correlated to the asymmetry degree of interactions. (paper: classical statistical mechanics, equilibrium and non-equilibrium)

Non interacting control by measurement feedback

NARCIS (Netherlands)

Woude, van der J.W.

1987-01-01

In this paper we shall solve the problem of non interacting control by measurement feedback for systems that in addition to a control input and a measurement output have two exogenous inputs and two exogenous outputs. That is, we shall derive necessary and sufficient conditions that can actually be

Interactive Control System, Intended Strategy, Implemented Strategy dan Emergent Strategy

Directory of Open Access Journals (Sweden)

Tubagus Ismail

2012-09-01

Full Text Available The purpose of this study was to examine the relationship between management control system (MCS and strategy formation processes, namely: intended strategy, emergent strategy and impelemented strategy. The focus of MCS in this study was interactive control system. The study was based on Structural Equation Modeling (SEM as its multivariate analyses instrument. The samples were upper middle managers of manufacturing company in Banten Province, DKI Jakarta Province and West Java Province. AMOS Software 16 program is used as an additional instrument to resolve the problem in SEM modeling. The study found that interactive control system brought a positive and significant influence on Intended strategy; interactive control system brought a positive and significant influence on implemented strategy; interactive control system brought a positive and significant influence on emergent strategy. The limitation of this study is that our empirical model only used one way relationship between the process of strategy formation and interactive control system.

Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

Science.gov (United States)

Corradini, Patricia Gon; Pires, Felipe I.; Paganin, Valdecir A.; Perez, Joelma; Antolini, Ermete

2012-09-01

The effect of the relationship between particle size ( d), inter-particle distance ( x i ), and metal loading ( y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5-3 nm) and x i / d (>5) values, was evaluated. It was found that for y fuel cell electrode than that using catalysts with y ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x i / d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.

Rheology and scaling behavior of swelling clay dispersions | Chaoui ...

African Journals Online (AJOL)

The microstructure and scaling of rheological properties of colloidal gels of bentonite investigated as a function of volume fraction and strength of interparticle interaction over a range of volume fractions, elastic modulus is well described with a scaling law functions of volume fractions, while the role of interparticle attractions ...

Controlling Non-Equilibrium Structure Formation on the Nanoscale.

Science.gov (United States)

Buchmann, Benedikt; Hecht, Fabian Manfred; Pernpeintner, Carla; Lohmueller, Theobald; Bausch, Andreas R

2017-12-06

Controlling the structure formation of gold nanoparticle aggregates is a promising approach towards novel applications in many fields, ranging from (bio)sensing to (bio)imaging to medical diagnostics and therapeutics. To steer structure formation, the DNA-DNA interactions of DNA strands that are coated on the surface of the particles have become a valuable tool to achieve precise control over the interparticle potentials. In equilibrium approaches, this technique is commonly used to study particle crystallization and ligand binding. However, regulating the structural growth processes from the nano- to the micro- and mesoscale remains elusive. Here, we show that the non-equilibrium structure formation of gold nanoparticles can be stirred in a binary heterocoagulation process to generate nanoparticle clusters of different sizes. The gold nanoparticles are coated with sticky single stranded DNA and mixed at different stoichiometries and sizes. This not only allows for structural control but also yields access to the optical properties of the nanoparticle suspensions. As a result, we were able to reliably control the kinetic structure formation process to produce cluster sizes between tens of nanometers up to micrometers. Consequently, the intricate optical properties of the gold nanoparticles could be utilized to control the maximum of the nanoparticle suspension extinction spectra between 525 nm and 600 nm. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of the size of charged spherical macroparticles on their electrostatic interaction in an equilibrium plasma

Energy Technology Data Exchange (ETDEWEB)

Filippov, A. V., E-mail: fav@triniti.ru; Derbenev, I. N. [State Research Center of the Russian Federation, Troitsk Institute for Innovation and Fusion Research (Russian Federation)

2016-12-15

The effect of the size of two charged spherical macroparticles on their electrostatic interaction in an equilibrium plasma is analyzed within the linearized Poisson–Botzmann model. It is established that, under the interaction of two charged dielectric macroparticles in an equilibrium plasma, the forces acting on each particle turn out to be generally unequal. The forces become equal only in the case of conducting macroparticles or in the case of dielectric macroparticles of the same size and charge. They also turn out to be equal when the surface potentials of the macroparticles remain constant under the variation of interparticle distances. Formulas are proposed that allow one to calculate the interaction force with a high degree of accuracy under the condition that the radii of macroparticles are much less than the screening length, which is usually satisfied in experiments with dusty plasmas.

Java interface for asserting interactive telerobotic control

Science.gov (United States)

DePasquale, Peter; Lewis, John; Stein, Matthew R.

1997-12-01

Many current web-based telerobotic interfaces use HyperText Markup Language (HTML) forms to assert user control on a robot. While acceptable for some tasks, a Java interface can provide better client-server interaction. The Puma Paint project is a joint effort between the Department of Computing Sciences at Villanova University and the Department of Mechanical and Materials Engineering at Wilkes University. THe project utilizes a Java applet to control a Unimation Puma 1760 robot during the task of painting on a canvas. The interface allows the user to control the paint strokes as well as the pressure of a brush on the canvas and how deep the brush is dipped into a paint jar. To provide immediate feedback, a virtual canvas models the effects of the controls as the artist paints. Live color video feedback is provided, allowing the user to view the actual results of the robot's motions. Unlike the step-at-a-time model of many web forms, the application permits the user to assert interactive control. The greater the complexity of the interaction between the robot and its environment, the greater the need for high quality information presentation to the user. The use of Java allows the sophistication of the user interface to be raised to the level required for satisfactory control. This paper describes the Puma Paint project, including the interface and communications model. It also examines the challenges of using the Internet as the medium of communications and the challenges of encoding free ranging motions for transmission from the client to the robot.

Theoretical Studies of Strongly Interacting Fine Particle Systems

Science.gov (United States)

Fearon, Michael

Available from UMI in association with The British Library. A theoretical analysis of the time dependent behaviour of a system of fine magnetic particles as a function of applied field and temperature was carried out. The model used was based on a theory assuming Neel relaxation with a distribution of particle sizes. This theory predicted a linear variation of S_{max} with temperature and a finite intercept, which is not reflected by experimental observations. The remanence curves of strongly interacting fine-particle systems were also investigated theoretically. It was shown that the Henkel plot of the dc demagnetisation remanence vs the isothermal remanence is a useful representation of interactions. The form of the plot was found to be a reflection of the magnetic and physical microstructure of the material, which is consistent with experimental data. The relationship between the Henkel plot and the noise of a particulate recording medium, another property dependent on the microstructure, is also considered. The Interaction Field Factor (IFF), a single parameter characterising the non-linearity of the Henkel plot, is investigated. These results are consistent with a previous experimental study. Finally the results of the noise power spectral density for erased and saturated recording media are presented, so that characterisation of interparticle interactions may be carried out with greater accuracy.

Visual analytics of geo-social interaction patterns for epidemic control.

Science.gov (United States)

Luo, Wei

2016-08-10

Human interaction and population mobility determine the spatio-temporal course of the spread of an airborne disease. This research views such spreads as geo-social interaction problems, because population mobility connects different groups of people over geographical locations via which the viruses transmit. Previous research argued that geo-social interaction patterns identified from population movement data can provide great potential in designing effective pandemic mitigation. However, little work has been done to examine the effectiveness of designing control strategies taking into account geo-social interaction patterns. To address this gap, this research proposes a new framework for effective disease control; specifically this framework proposes that disease control strategies should start from identifying geo-social interaction patterns, designing effective control measures accordingly, and evaluating the efficacy of different control measures. This framework is used to structure design of a new visual analytic tool that consists of three components: a reorderable matrix for geo-social mixing patterns, agent-based epidemic models, and combined visualization methods. With real world human interaction data in a French primary school as a proof of concept, this research compares the efficacy of vaccination strategies between the spatial-social interaction patterns and the whole areas. The simulation results show that locally targeted vaccination has the potential to keep infection to a small number and prevent spread to other regions. At some small probability, the local control strategies will fail; in these cases other control strategies will be needed. This research further explores the impact of varying spatial-social scales on the success of local vaccination strategies. The results show that a proper spatial-social scale can help achieve the best control efficacy with a limited number of vaccines. The case study shows how GS-EpiViz does support the design

To the Problem of Electromechanical Interaction in Elevators with Controlled Electric Drive and Fuzzy Speed Controller

Directory of Open Access Journals (Sweden)

A. S. Koval

2010-01-01

Full Text Available The paper considers problems concerning electromechanical interaction in elevators with an adjustable asynchronous electric drive equipped with the vector control systems under direct torque control and direct torque control with pulse-width modulator. A mathematical description of electromechanical elevator system with due account of nonlinearity of the worm gear is given in the paper. The paper presents a simplified circuit design of a control system with a fuzzy speed controller. It has been established that the factor of electromechanical interaction in electromechanical system with the adjustable asynchronous electric drive and an fuzzy speed controller is within the range which corresponds to existence of the essential electromechanical interaction.

A plasmonic fluid with dynamically tunable optical properties

KAUST Repository

Bhattacharjee, Rama Ranjan; Li, Ruipeng; Esté vez, Luis Antonio; Smilgies, Detlef Matthias; Amassian, Aram; Giannelis, Emmanuel P.

2009-01-01

We report the first synthesis of a gold nanorod (GNR)-based nanocomposite that exhibits solid-like plasmonic properties while behaving in a liquid-like manner. Tuning the degree of GNR clustering controls the material's responsiveness to external stimuli, such as mechanical shearing, due to the sensitivity of the localized surface plasmon resonance to interparticle interactions. © 2009 The Royal Society of Chemistry.

A plasmonic fluid with dynamically tunable optical properties

KAUST Repository

Bhattacharjee, Rama Ranjan

2009-01-01

We report the first synthesis of a gold nanorod (GNR)-based nanocomposite that exhibits solid-like plasmonic properties while behaving in a liquid-like manner. Tuning the degree of GNR clustering controls the material\\'s responsiveness to external stimuli, such as mechanical shearing, due to the sensitivity of the localized surface plasmon resonance to interparticle interactions. © 2009 The Royal Society of Chemistry.

Controlling Second Harmonic Efficiency of Laser Beam Interactions

Science.gov (United States)

Barnes, Norman P. (Inventor); Walsh, Brian M. (Inventor); Reichle, Donald J. (Inventor)

2011-01-01

A method is provided for controlling second harmonic efficiency of laser beam interactions. A laser system generates two laser beams (e.g., a laser beam with two polarizations) for incidence on a nonlinear crystal having a preferred direction of propagation. Prior to incidence on the crystal, the beams are optically processed based on the crystal's beam separation characteristics to thereby control a position in the crystal along the preferred direction of propagation at which the beams interact.

Perturbation theory of the periodic Anderson lattice and superconductivity

International Nuclear Information System (INIS)

Geertsuma, W.

1988-01-01

In this paper the author develops a perturbation calculation of the second and fourth order interparticle interaction in band states, based on the Periodic Anderson Lattice. The author shows that 4th order interparticle interactions giving rise to the well known Kondo effect vanish in the superconducting ground state. This term survives in the presence of a magnetic field. Pair excitations can only give rise to an appreciable attractive contribution when the d states are less than half filled and the pair energy is near the Fermi level. The only important attractive interaction comes from the normal fourth order terms

Kinetic Assembly of Near-IR Active Gold Nanoclusters using Weakly Adsorbing Polymers to Control Size

Science.gov (United States)

Tam, Jasmine M.; Murthy, Avinash K.; Ingram, Davis R.; Nguyen, Robin; Sokolov, Konstantin V.; Johnston, Keith P.

2013-01-01

Clusters of metal nanoparticles with an overall size less than 100 nm and high metal loadings for strong optical functionality, are of interest in various fields including microelectronics, sensors, optoelectronics and biomedical imaging and therapeutics. Herein we assemble ~5 nm gold particles into clusters with controlled size, as small as 30 nm and up to 100 nm, which contain only small amounts of polymeric stabilizers. The assembly is kinetically controlled with weakly adsorbing polymers, PLA(2K)-b-PEG(10K)-b-PLA(2K) or PEG (MW = 3350), by manipulating electrostatic, van der Waals (VDW), steric, and depletion forces. The cluster size and optical properties are tuned as a function of particle volume fractions and polymer/gold ratios to modulate the interparticle interactions. The close spacing between the constituent gold nanoparticles and high gold loadings (80–85% w/w gold) produce a strong absorbance cross section of ~9×10−15 m2 in the NIR at 700 nm. This morphology results from VDW and depletion attractive interactions that exclude the weakly adsorbed polymeric stabilizer from the cluster interior. The generality of this kinetic assembly platform is demonstrated for gold nanoparticles with a range of surface charges from highly negative to neutral, with the two different polymers. PMID:20361735

Natural enemy interactions constrain pest control in complex agricultural landscapes.

Science.gov (United States)

Martin, Emily A; Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

2013-04-02

Biological control of pests by natural enemies is a major ecosystem service delivered to agriculture worldwide. Quantifying and predicting its effectiveness at large spatial scales is critical for increased sustainability of agricultural production. Landscape complexity is known to benefit natural enemies, but its effects on interactions between natural enemies and the consequences for crop damage and yield are unclear. Here, we show that pest control at the landscape scale is driven by differences in natural enemy interactions across landscapes, rather than by the effectiveness of individual natural enemy guilds. In a field exclusion experiment, pest control by flying insect enemies increased with landscape complexity. However, so did antagonistic interactions between flying insects and birds, which were neutral in simple landscapes and increasingly negative in complex landscapes. Negative natural enemy interactions thus constrained pest control in complex landscapes. These results show that, by altering natural enemy interactions, landscape complexity can provide ecosystem services as well as disservices. Careful handling of the tradeoffs among multiple ecosystem services, biodiversity, and societal concerns is thus crucial and depends on our ability to predict the functional consequences of landscape-scale changes in trophic interactions.

Investigation of interactions in a biological membrane using structure factor/pair correlation function approach: a first communication on nerve myelin

International Nuclear Information System (INIS)

Gbordzoe, M.K.

1984-09-01

Interactions in biological and artificial membranes have been studied by applying mostly the methods of biochemical analysis and determination of thermodynamic parameters related to phase transition phenomena. Structure factor, obtained by measuring scattered intensity from small-angle X-ray or neutron scattering experiments, has been used mainly for determining electron density distribution. Drawing upon the experience of the theory of liquids, where Johnson and March (1963) and Johnson, Hutchinson and March (1964) first established the possibility of deriving interparticle potential from experimental measurement of structure factor, it is suggested that structure factor/distance correlation function approach, can be a useful method for studying interactions between various membrane components. Preliminary experimental data presented for nerve myelin are to demonstrate the possibility of studying interactions from the distance correlation function of a membrane pair. (author)

Phase transitions in ideal and weakly interacting Bose gases with a finite number of particles confined in a box

International Nuclear Information System (INIS)

Wang Jianhui; Ma Yongli

2009-01-01

We generalize the scheme to characterize phase transitions of finite systems in a complex temperature plane and approach the classifications of phase transitions in ideal and weakly interacting Bose gases of a finite number of particles, confined in a cubic box of volume L 3 with different boundary conditions. For this finite ideal Bose system, by extending the classification parameters to all regions, we predict that the phase transition for periodic boundary conditions is of second order, while the transition in Dirichlet boundary conditions is of first order. For a weakly interacting Bose gas with periodic boundary conditions, we discuss the effects of finite particle numbers and inter-particle interactions on the nature of the phase transitions. We show that this homogenous weakly interacting Bose gas undergoes a second-order phase transition, which is in accordance with universality arguments for infinite systems. We also discuss the dependence of transition temperature on interaction strengths and particle numbers.

Prosthetic Leg Control in the Nullspace of Human Interaction.

Science.gov (United States)

Gregg, Robert D; Martin, Anne E

2016-07-01

Recent work has extended the control method of virtual constraints, originally developed for autonomous walking robots, to powered prosthetic legs for lower-limb amputees. Virtual constraints define desired joint patterns as functions of a mechanical phasing variable, which are typically enforced by torque control laws that linearize the output dynamics associated with the virtual constraints. However, the output dynamics of a powered prosthetic leg generally depend on the human interaction forces, which must be measured and canceled by the feedback linearizing control law. This feedback requires expensive multi-axis load cells, and actively canceling the interaction forces may minimize the human's influence over the prosthesis. To address these limitations, this paper proposes a method for projecting virtual constraints into the nullspace of the human interaction terms in the output dynamics. The projected virtual constraints naturally render the output dynamics invariant with respect to the human interaction forces, which instead enter into the internal dynamics of the partially linearized prosthetic system. This method is illustrated with simulations of a transfemoral amputee model walking with a powered knee-ankle prosthesis that is controlled via virtual constraints with and without the proposed projection.

Central control of cardiorespiratory interactions in fish.

Science.gov (United States)

Taylor, Edwin W; Leite, Cleo A C; Levings, Jennifer J

2009-01-01

Fish control the relative flow rates of water and blood over the gills in order to optimise respiratory gas exchange. As both flows are markedly pulsatile, close beat-to-beat relationships can be predicted. Cardiorespiratory interactions in fish are controlled primarily by activity in the parasympathetic nervous system that has its origin in cardiac vagal preganglionic neurons. Recordings of efferent activity in the cardiac vagus include units firing in respiration-related bursts. Bursts of electrical stimuli delivered peripherally to the cardiac vagus or centrally to respiratory branches of cranial nerves can recruit the heart over a range of frequencies. So, phasic, efferent activity in cardiac vagi, that in the intact fish are respiration-related, can cause heart rate to be modulated by the respiratory rhythm. In elasmobranch fishes this phasic activity seems to arise primarily from central feed-forward interactions with respiratory motor neurones that have overlapping distributions with cardiac neurons in the brainstem. In teleost fish, they arise from increased levels of efferent vagal activity arising from reflex stimulation of chemoreceptors and mechanoreceptors in the orobranchial cavity. However, these differences are largely a matter of emphasis as both groups show elements of feed-forward and feed-back control of cardiorespiratory interactions.

Screening length in dusty plasma crystals

International Nuclear Information System (INIS)

Nikolaev, V S; Timofeev, A V

2016-01-01

Particles interaction and value of the screening length in dusty plasma systems are of great interest in dusty plasma area. Three inter-particle potentials (Debye potential, Gurevich potential and interaction potential in the weakly collisional regime) are used to solve equilibrium equations for two dusty particles suspended in a parabolic trap. The inter-particle distance dependence on screening length, trap parameter and particle charge is obtained. The functional form of inter-particle distance dependence on ion temperature is investigated and compared with experimental data at 200-300 K in order to test used potentials applicability to dusty plasma systems at room temperatures. The preference is given to the Yukawa-type potential including effective values of particle charge and screening length. The estimated effective value of the screening length is 5-15 times larger than the Debye length. (paper)

Web-based interactive drone control using hand gesture

Science.gov (United States)

Zhao, Zhenfei; Luo, Hao; Song, Guang-Hua; Chen, Zhou; Lu, Zhe-Ming; Wu, Xiaofeng

2018-01-01

This paper develops a drone control prototype based on web technology with the aid of hand gesture. The uplink control command and downlink data (e.g., video) are transmitted by WiFi communication, and all the information exchange is realized on web. The control command is translated from various predetermined hand gestures. Specifically, the hardware of this friendly interactive control system is composed by a quadrotor drone, a computer vision-based hand gesture sensor, and a cost-effective computer. The software is simplified as a web-based user interface program. Aided by natural hand gestures, this system significantly reduces the complexity of traditional human-computer interaction, making remote drone operation more intuitive. Meanwhile, a web-based automatic control mode is provided in addition to the hand gesture control mode. For both operation modes, no extra application program is needed to be installed on the computer. Experimental results demonstrate the effectiveness and efficiency of the proposed system, including control accuracy, operation latency, etc. This system can be used in many applications such as controlling a drone in global positioning system denied environment or by handlers without professional drone control knowledge since it is easy to get started.

Web-based interactive drone control using hand gesture.

Science.gov (United States)

Zhao, Zhenfei; Luo, Hao; Song, Guang-Hua; Chen, Zhou; Lu, Zhe-Ming; Wu, Xiaofeng

2018-01-01

This paper develops a drone control prototype based on web technology with the aid of hand gesture. The uplink control command and downlink data (e.g., video) are transmitted by WiFi communication, and all the information exchange is realized on web. The control command is translated from various predetermined hand gestures. Specifically, the hardware of this friendly interactive control system is composed by a quadrotor drone, a computer vision-based hand gesture sensor, and a cost-effective computer. The software is simplified as a web-based user interface program. Aided by natural hand gestures, this system significantly reduces the complexity of traditional human-computer interaction, making remote drone operation more intuitive. Meanwhile, a web-based automatic control mode is provided in addition to the hand gesture control mode. For both operation modes, no extra application program is needed to be installed on the computer. Experimental results demonstrate the effectiveness and efficiency of the proposed system, including control accuracy, operation latency, etc. This system can be used in many applications such as controlling a drone in global positioning system denied environment or by handlers without professional drone control knowledge since it is easy to get started.

The double meaning of control: three-way interactions between internal resources, job control, and stressors at work.

Science.gov (United States)

Meier, Laurenz L; Semmer, Norbert K; Elfering, Achim; Jacobshagen, Nicola

2008-07-01

The Job Demand-Control model postulates that job control attenuates the effects of job demands on health and well-being. Support for this interactive effect is rather weak. Conceivably, it holds only when there is a match between job control and individual characteristics that relate to exercising control options, such as locus of control, or self-efficacy. This three-way interaction was tested in a sample of 96 service employees, with affective strain and musculoskeletal pain as dependent variables. As hypothesized, job control attenuated the effects of stressors only for people with an internal locus of control. For people with an external locus of control, job control actually predicted poorer well-being and health as stressors increased. For self-efficacy, the corresponding three-way interaction was significant with regard to affective strain. Copyright (c) 2008 APA, all rights reserved.

Interaction and control in wearable computing

International Nuclear Information System (INIS)

Strand, Ole Morten; Johansen, Paal; Droeivoldsmo, Asgeir; Reigstad, Magnus; Olsen, Asle; Helgar, Stein

2004-03-01

This report presents the status of Halden Virtual Reality Centre (HVRC) work with technological solutions for wearable computing to support operations where interaction and control of wearable information and communication systems for plant floor personnel are of importance. The report describes a framework and system prototype developed for testing technology, usability and applicability of eye movements and speech for controlling wearable equipment while having both hands free. Potentially interesting areas for further development are discussed with regard to the effect they have on the work situation for plant floor personnel using computerised wearable systems. (Author)

Vesicle fusion with bilayer lipid membrane controlled by electrostatic interaction

Directory of Open Access Journals (Sweden)

Azusa Oshima

2017-09-01

Full Text Available The fusion of proteoliposomes is a promising approach for incorporating membrane proteins in artificial lipid membranes. In this study, we employed an electrostatic interaction between vesicles and supported bilayer lipid membranes (s-BLMs to control the fusion process. We combined large unilamellar vesicles (LUVs containing anionic lipids, which we used instead of proteoliposomes, and s-BLMs containing cationic lipids to control electrostatic interaction. Anionic LUVs were never adsorbed or ruptured on the SiO2 substrate with a slight negative charge, and selectively fused with cationic s-BLMs. The LUVs can be fused effectively to the target position. Furthermore, as the vesicle fusion proceeds and some of the positive charges are neutralized, the attractive interaction weakens and finally the vesicle fusion saturates. In other words, we can control the number of LUVs fused with s-BLMs by controlling the concentration of the cationic lipids in the s-BLMs. The fluidity of the s-BLMs after vesicle fusion was confirmed to be sufficiently high. This indicates that the LUVs attached to the s-BLMs were almost completely fused, and there were few intermediate state vesicles in the fusion process. We could control the position and amount of vesicle fusion with the s-BLMs by employing an electrostatic interaction.

Energy dissipation of rigid dipoles in a viscous fluid under the action of a time-periodic field: The influence of thermal bath and dipole interaction

Science.gov (United States)

Lyutyy, T. V.; Reva, V. V.

2018-05-01

Ferrofluid heating by an external alternating field is studied based on the rigid dipole model, where the magnetization of each particle in a fluid is supposed to be firmly fixed in the crystal lattice. Equations of motion, employing Newton's second law for rotational motion, the condition of rigid body rotation, and the assumption that the friction torque is proportional to angular velocity are used. This oversimplification permits us to expand the model easily: to take into account the thermal noise and interparticle interaction that allows us to estimate from unified positions the role of thermal activation and dipole interaction in the heating process. Our studies are conducted in three stages. The exact expressions for the average power loss of a single particle are obtained within the dynamical approximation. Then, in the stochastic case, the power loss of a single particle is estimated analytically using the Fokker-Planck equation and numerically using the effective Langevin equation. Finally, the power loss for the particle ensemble is obtained using the molecular dynamics method. Here, the local dipole fields are calculated approximately based on the Barnes-Hut algorithm. The revealed trends in the behavior of both a single particle and the particle ensemble suggest the way of choosing the conditions for obtaining the maximum heating efficiency. The competitiveness character of the interparticle interaction and thermal noise is investigated in detail. Two situations, when the thermal noise rectifies the power loss reduction caused by the interaction, are described. The first of them is related to the complete destruction of dense clusters at high noise intensity. The second one originates from the rare switching of the particles in clusters due to thermal activation, when the noise intensity is relatively weak. In this way, the constructive role of noise appears in the system.

Tracking control of time-varying knee exoskeleton disturbed by interaction torque.

Science.gov (United States)

Li, Zhan; Ma, Wenhao; Yin, Ziguang; Guo, Hongliang

2017-11-01

Knee exoskeletons have been increasingly applied as assistive devices to help lower-extremity impaired people to make their knee joints move through providing external movement compensation. Tracking control of knee exoskeletons guided by human intentions often encounters time-varying (time-dependent) issues and the disturbance interaction torque, which may dramatically put an influence up on their dynamic behaviors. Inertial and viscous parameters of knee exoskeletons can be estimated to be time-varying due to unexpected mechanical vibrations and contact interactions. Moreover, the interaction torque produced from knee joint of wearers has an evident disturbance effect on regular motions of knee exoskeleton. All of these points can increase difficultly of accurate control of knee exoskeletons to follow desired joint angle trajectories. This paper proposes a novel control strategy for controlling knee exoskeleton with time-varying inertial and viscous coefficients disturbed by interaction torque. Such designed controller is able to make the tracking error of joint angle of knee exoskeletons exponentially converge to zero. Meanwhile, the proposed approach is robust to guarantee the tracking error bounded when the interaction torque exists. Illustrative simulation and experiment results are presented to show efficiency of the proposed controller. Additionally, comparisons with gradient dynamic (GD) approach and other methods are also presented to demonstrate efficiency and superiority of the proposed control strategy for tracking joint angle of knee exoskeleton. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Parental Interaction Patterns in Children with Adhd and Controls; a Comparative Study

Directory of Open Access Journals (Sweden)

M Afkhami -Aghda

2007-04-01

Full Text Available Introduction: Communicational patterns of the parents can either positively or negatively influence children's personality. Parenting manner has long-term effects on behavior, function, expectations and eventually people's future personality. This study investigates parental interaction patterns in children with attention deficit- hyperactive disorder. Methods :In this study, 50 male children aged 7-12 years were selected in two groups including 1 25 students with ADHD referring to psychiatry clinics in Isfahan according to the diagnostic scale of DSM- IV and 2 25 healthy boys selected by random cluster multistage sampling from primary schools in five districts of Isfahan from Septamber 2005 until March 2005. Schaffer and Edgerton parental interaction questionnaire was filled for them. Results: In "Communication" interaction pattern, the mean score of healthy children was 15.08, while the mean score of ADHD children was 13.42. In "admission" interactional pattern; the mean of the first group was 14.76, while the second group was 11.76. In "control" interactional pattern, mean of group one was 13.28 and the second group was 11.76. In "aggression control" interactional pattern, the mean of group one was 13 and the second group was 14.68. In "lack of aggressive attachment" interactional pattern, mean of the first group was 13.36 and the second group was 16.67. The mean scores of parental interactional pattern in healthy children were all higher than ADHD children except for "aggression control" and "lack of aggressive attachment" interactional patterns. Conclusion: The more the parental "admission" interactional pattern score, the lower the signs of ADHD in children. The signs of severity are lower in cases with more positive parental "control" interactional patterns. If the scores of "lack of aggressive/ attachment" and "aggressive/ control" interactional patterns are higher, ADHD signs are more severe.

Nanoscale tissue engineering: spatial control over cell-materials interactions

International Nuclear Information System (INIS)

Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Khademhosseini, Ali; Jabbari, Esmaiel

2011-01-01

Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

Nonequilibrium statistical mechanics of systems with long-range interactions

Energy Technology Data Exchange (ETDEWEB)

Levin, Yan, E-mail: levin@if.ufrgs.br; Pakter, Renato, E-mail: pakter@if.ufrgs.br; Rizzato, Felipe B., E-mail: rizzato@if.ufrgs.br; Teles, Tarcísio N., E-mail: tarcisio.teles@fi.infn.it; Benetti, Fernanda P.C., E-mail: fbenetti@if.ufrgs.br

2014-02-01

Systems with long-range (LR) forces, for which the interaction potential decays with the interparticle distance with an exponent smaller than the dimensionality of the embedding space, remain an outstanding challenge to statistical physics. The internal energy of such systems lacks extensivity and additivity. Although the extensivity can be restored by scaling the interaction potential with the number of particles, the non-additivity still remains. Lack of additivity leads to inequivalence of statistical ensembles. Before relaxing to thermodynamic equilibrium, isolated systems with LR forces become trapped in out-of-equilibrium quasi-stationary states (qSSs), the lifetime of which diverges with the number of particles. Therefore, in the thermodynamic limit LR systems will not relax to equilibrium. The qSSs are attained through the process of collisionless relaxation. Density oscillations lead to particle–wave interactions and excitation of parametric resonances. The resonant particles escape from the main cluster to form a tenuous halo. Simultaneously, this cools down the core of the distribution and dampens out the oscillations. When all the oscillations die out the ergodicity is broken and a qSS is born. In this report, we will review a theory which allows us to quantitatively predict the particle distribution in the qSS. The theory is applied to various LR interacting systems, ranging from plasmas to self-gravitating clusters and kinetic spin models.

Analysis of airframe/engine interactions in integrated flight and propulsion control

Science.gov (United States)

Schierman, John D.; Schmidt, David K.

1991-01-01

An analysis framework for the assessment of dynamic cross-coupling between airframe and engine systems from the perspective of integrated flight/propulsion control is presented. This analysis involves to determining the significance of the interactions with respect to deterioration in stability robustness and performance, as well as critical frequency ranges where problems may occur due to these interactions. The analysis illustrated here investigates both the airframe's effects on the engine control loops and the engine's effects on the airframe control loops in two case studies. The second case study involves a multi-input/multi-output analysis of the airframe. Sensitivity studies are performed on critical interactions to examine the degradations in the system's stability robustness and performance. Magnitudes of the interactions required to cause instabilities, as well as the frequencies at which the instabilities occur are recorded. Finally, the analysis framework is expanded to include control laws which contain cross-feeds between the airframe and engine systems.

Interactional Organization and Topic Control in Conciliation Hearings

Directory of Open Access Journals (Sweden)

Wânia Terezinha Ladeira

2011-07-01

Full Text Available We analyse discursive topic in talk-in-interaction within the institutional setting of three conciliation hearings held in a kind of small claims court for consumption conflict resolution. This research is based on Interactional Sociolinguistics and Conversation Analysis theories. The analysis shows that the participants of those meetings have asymmetric rights regarding the choice of discussion topics. Thus, the mediator is the one who has the right to suggest and control the discursive topics of the conversation. This topic control is the most important institutional procedure that can cause a reduction in accusations and adjacent replies. Consequently, the chance of mediators achieving their institutional task of reaching an agreement between parts in conflict is increased.

Inter-particle interactions and magnetocaloric effect in a sample of ultrafine Fe1-x Hgx particles in Hg

DEFF Research Database (Denmark)

Pedersen, Michael Stanley; Mørup, Steen; Linderoth, S.

1997-01-01

to a state in which the magnetic moments of the particles are ordered. The magnetic entropy change induced by application of a magnetic field was determined in the temperature range from 70 to 200 K. When the sample was magnetized in 1 T the magnetic entropy change was almost constant in the temperature...... range from 130 to 200 K. In an applied field of 0.1 T, the entropy change was lower, and decreased with increasing temperature in the same temperature range. A model which takes into account the magnetic interactions between the particles was found to give a better description of the magnetic entropy...

Control of the interparticle spacing in gold nanoparticle superlattices

Energy Technology Data Exchange (ETDEWEB)

MARTIN,JAMES E.; WILCOXON,JESS P.; ODINEK,JUDY G.; PROVENCIO,PAULA P.

2000-04-06

The authors have investigated the formation of 2-D and 3-D superlattices of Au nanoclusters synthesized in nonionic inverse micelles, and capped with alkyl thiol ligands, with alkane chains ranging from C{sub 6} to C1{sub 18}. The thiols are found to play a significant role in the ripening of these nanoclusters, and in the formation of superlattices. Image processing techniques were developed to reliably extract from transmission electron micrographs (TEMs) the particle size distribution, and information about the superlattice domains and their boundaries. The latter permits one to compute the intradomain vector pair correlation function, from which one can accurately determine the lattice spacing and the coherent domain size. From these data the gap between the particles in the coherent domains can be determined as a function of the thiol chain length. It is found that as the thiol chain length increases, the nanoclusters become more polydisperse and larger, and the gaps between particles within superlattice domains increases. Annealing studies at elevated temperatures confirm nanocluster ripening. Finally, the effect of the particle gaps on physical properties is illustrated by computing the effective dielectric constant, and it is shown that the gap size now accessible in superlattices is rather large for dielectric applications.

Physics of plasma-wall interactions in controlled fusion

International Nuclear Information System (INIS)

Post, D.E.; Behrisch, R.

1984-01-01

In the areas of plasma physics, atomic physics, surface physics, bulk material properties and fusion experiments and theory, the following topics are presented: the plasma sheath; plasma flow in the sheath and presheath of a scrape-off layer; probes for plasma edge diagnostics in magnetic confinement fusion devices; atomic and molecular collisions in the plasma boundary; physical sputtering of solids at ion bombardment; chemical sputtering and radiation enhanced sublimation of carbon; ion backscattering from solid surfaces; implantation, retention and release of hydrogen isotopes; surface erosion by electrical arcs; electron emission from solid surfaces;l properties of materials; plasma transport near material boundaries; plasma models for impurity control experiments; neutral particle transport; particle confinement and control in existing tokamaks; limiters and divertor plates; advanced limiters; divertor tokamak experiments; plasma wall interactions in heated plasmas; plasma-wall interactions in tandem mirror machines; and impurity control systems for reactor experiments

dSPACE based adaptive neuro-fuzzy controller of grid interactive inverter

International Nuclear Information System (INIS)

Altin, Necmi; Sefa, İbrahim

2012-01-01

Highlights: ► We propose a dSPACE based neuro-fuzzy controlled grid interactive inverter. ► The membership functions and rule base of fuzzy logic controller by using ANFIS. ► A LCL output filter is designed. ► A high performance controller is designed. - Abstract: In this study, design, simulation and implementation of a dSPACE based grid interactive voltage source inverter are proposed. This inverter has adaptive neuro-fuzzy controller and capable of importing electrical energy, generated from renewable energy sources such as the wind, the solar and the fuel cells to the grid. A line frequency transformer and a LCL filter are used at the output of the grid interactive inverter which is designed as current controlled to decrease the susceptibility to phase errors. Membership functions and rule base of the fuzzy logic controller, which control the inverter output current, are determined by using artificial neural networks. Both simulation and experimental results show that, the grid interactive inverter operates synchronously with the grid. The inverter output current which is imported to the grid is in sinusoidal waveform and the harmonic level of it meets the international standards (4.3 < 5.0%). In addition, simulation and experimental results of the neuro-fuzzy and the PI controlled inverter are given together and compared in detail. Simulation and experimental results show that the proposed inverter has faster response to the reference variations and lower steady state error than PI controller.

Dust crystal in the electrode sheath of a gaseous discharge

International Nuclear Information System (INIS)

Schweigert, I.V.; Schweigert, V.A.

2002-01-01

The phenomena observed in strongly coupled dusty plasmas in the electrode sheath of gas discharge clearly indicate that the screened Coulomb potential is not valid for inter-particle interaction. The reason why the conventional model breaks down is clear now. The strong electric field, accelerating ions toward the cathode, leads to an asymmetrical particle shielding and the appearance of an attractive component in the inter-particle force. The sheath plasma with micro-particles is non Hamiltonian system because of input of energy from ion flux from the bulk plasma. The models of interaction potential of microparticles in sheath are proposed. The first is the linear effective positive charge (EPC). On the basis of this model the stability of the dust crystal in the sheath is analyzed both analytically and in MD simulations. The scenario of crystal melting is described. The role of different types of defects in the local heating of the crystal is considered. The next non-linear model of sheath plasma with micro-particles allows to find all parameter of plasma crystal: particle charge, inter-particle distance and study the structural transition. We constructed the analytical expression for inter-particle potential and have found the mechanism acceleration of extra particle beneath the monolayer. Recently new more simple analytical kinetic approach, accounting for ion collisions, have been developed. The structural transition in the dust molecular was obtained in simulation with multipole expansion model interaction potential

Interactive animated displayed of man-controlled and autonomous robots

International Nuclear Information System (INIS)

Crane, C.D. III; Duffy, J.

1986-01-01

An interactive computer graphics program has been developed which allows an operator to more readily control robot motions in two distinct modes; viz., man-controlled and autonomous. In man-controlled mode, the robot is guided by a joystick or similar device. As the robot moves, actual joint angle information is measured and supplied to a graphics system which accurately duplicates the robot motion. Obstacles are placed in the actual and animated workspace and the operator is warned of imminent collisions by sight and sound via the graphics system. Operation of the system in man-controlled mode is shown. In autonomous mode, a collision-free path between specified points is obtained by previewing robot motions on the graphics system. Once a satisfactory path is selected, the path characteristics are transmitted to the actual robot and the motion is executed. The telepresence system developed at the University of Florida has been successful in demonstrating that the concept of controlling a robot manipulator with the aid of an interactive computer graphics system is feasible and practical. The clarity of images coupled with real-time interaction and real-time determination of imminent collision with obstacles has resulted in improved operator performance. Furthermore, the ability for an operator to preview and supervise autonomous operations is a significant attribute when operating in a hazardous environment

Plasma surface interactions in controlled fusion devices

Energy Technology Data Exchange (ETDEWEB)

Ghendrih, Ph.; Becoulet, M.; Costanzo, L. [and others

2000-07-01

This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak.

Plasma surface interactions in controlled fusion devices

International Nuclear Information System (INIS)

Ghendrih, Ph.; Becoulet, M.; Costanzo, L.

2000-07-01

This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak

Fiscal Interactions and the Costs of Controlling Pollution from Electricity

OpenAIRE

Parry, Ian

2004-01-01

This paper quantifies the costs of controlling SO2, carbon, and NOx emissions from power generation, accounting for interactions between environmental policies and the broader fiscal system. We distinguish a dirty technology (coal) that satisfies baseload demand and a clean technology (gas) that is used during peak periods, and we distinguish sectors with and without regulated prices. Estimated emissions control costs are substantially lower than in previous models of fiscal interactions that...

Effect of interaction strength on robustness of controlling edge dynamics in complex networks

Science.gov (United States)

Pang, Shao-Peng; Hao, Fei

2018-05-01

Robustness plays a critical role in the controllability of complex networks to withstand failures and perturbations. Recent advances in the edge controllability show that the interaction strength among edges plays a more important role than network structure. Therefore, we focus on the effect of interaction strength on the robustness of edge controllability. Using three categories of all edges to quantify the robustness, we develop a universal framework to evaluate and analyze the robustness in complex networks with arbitrary structures and interaction strengths. Applying our framework to a large number of model and real-world networks, we find that the interaction strength is a dominant factor for the robustness in undirected networks. Meanwhile, the strongest robustness and the optimal edge controllability in undirected networks can be achieved simultaneously. Different from the case of undirected networks, the robustness in directed networks is determined jointly by the interaction strength and the network's degree distribution. Moreover, a stronger robustness is usually associated with a larger number of driver nodes required to maintain full control in directed networks. This prompts us to provide an optimization method by adjusting the interaction strength to optimize the robustness of edge controllability.

Agrégats de nanoparticules magnétiques auto-assemblées

OpenAIRE

Frka-Petesic , Bruno

2010-01-01

Magnetic nanoparticles (MNPs) made of iron oxides are used as main components to obtain magnetic nanosized aggregates dispersed in aqueous media, either by tuning the interparticle interaction potential or by using semi-adsorbing copolymers.– Clusters of MNP’s are obtained by solely adjusting the interparticle potential. The ionic strength and the pH of the aqueous carrier tune the screening Debye length and the surface charge of the nanoparticles. These dispersions present ageing properties ...

An Interaction Measure for Control Configuration Selection for Multivariable Bilinear Systems

DEFF Research Database (Denmark)

Shaker, Hamid Reza; Stoustrup, Jakob

2013-01-01

are needed to be controlled, are nonlinear and linear models are insufficient to describe the behavior of the processes. The focus of this paper is on the problem of control configuration selection for a class of nonlinear systems which is known as bilinear systems. A gramian-based interaction measure...... for control configuration selection of MIMO bilinear processes is described. In general, most of the results on the control configuration selection, which have been proposed so far, can only support linear systems. The proposed gramian-based interaction measure not only supports bilinear processes but also...

Quantum chaos and thermalization in isolated systems of interacting particles

Energy Technology Data Exchange (ETDEWEB)

Borgonovi, F., E-mail: fausto.borgonovi@unicatt.it [Dipartimento di Matematica e Fisica and Interdisciplinary Laboratories for Advanced Materials Physics, Universitá Cattolica, via Musei 41, 25121 Brescia, and INFN, Sezione di Pavia (Italy); Izrailev, F.M., E-mail: felix.izrailev@gmail.com [Instituto de Física, Universidad Autónoma de Puebla, Apt. Postal J-48, Puebla, Pue., 72570 (Mexico); NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-1321 (United States); Santos, L.F., E-mail: lsantos2@yu.edu [Department of Physics, Yeshiva University, 245 Lexington Ave, New York, NY 10016 (United States); Zelevinsky, V.G., E-mail: Zelevins@nscl.msu.edu [NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-1321 (United States)

2016-04-15

This review is devoted to the problem of thermalization in a small isolated conglomerate of interacting constituents. A variety of physically important systems of intensive current interest belong to this category: complex atoms, molecules (including biological molecules), nuclei, small devices of condensed matter and quantum optics on nano- and micro-scale, cold atoms in optical lattices, ion traps. Physical implementations of quantum computers, where there are many interacting qubits, also fall into this group. Statistical regularities come into play through inter-particle interactions, which have two fundamental components: mean field, that along with external conditions, forms the regular component of the dynamics, and residual interactions responsible for the complex structure of the actual stationary states. At sufficiently high level density, the stationary states become exceedingly complicated superpositions of simple quasiparticle excitations. At this stage, regularities typical of quantum chaos emerge and bring in signatures of thermalization. We describe all the stages and the results of the processes leading to thermalization, using analytical and massive numerical examples for realistic atomic, nuclear, and spin systems, as well as for models with random parameters. The structure of stationary states, strength functions of simple configurations, and concepts of entropy and temperature in application to isolated mesoscopic systems are discussed in detail. We conclude with a schematic discussion of the time evolution of such systems to equilibrium.

Principles, techniques and recent advances in fine particle aggregation for solid-liquid separation

International Nuclear Information System (INIS)

Somasundaran, P.; Vasudevan, T.V.

1993-01-01

Waste water discharged from various chemical and nuclear processing operations contains dissolved metal species that are highly toxic and, in some cases, radioactive. When the waste is acidic in nature, neutralization using reagents such as lime is commonly practiced to reduce both the acidity and the amount of waste (Kuyucak et al.). The sludge that results from the neutralization process contains metal oxide or hydroxide precipitates that are colloidal in nature and is highly stable. Destabilization of colloidal suspensions can be achieved by aggregation of fines into larger sized agglomerates. Aggregation of fines is a complex phenomenon involving a multitude of forces that control the interparticle interaction. In order to understand the colloidal behavior of suspensions a fundamental knowledge of physicochemical properties that determine the various forces is essential. In this review, a discussion of basic principles governing the aggregation of colloidal fines, various ways in which interparticle forces can be manipulated to achieve the desired aggregation response and recent advances in experimental techniques to probe the interfacial characteristics that control the flocculation behavior are discussed

A spherical model with directional interactions: II. Dynamics and landscape properties

International Nuclear Information System (INIS)

Mayer, Christian; Sciortino, Francesco; Tartaglia, Piero; Zaccarelli, Emanuela

2010-01-01

We study a binary non-additive hard-sphere mixture with square well interactions only between dissimilar particles. An appropriate choice of the inter-particle potential parameters favors the formation of equilibrium structures with tetrahedral ordering (Zaccarelli et al 2007 J. Chem. Phys. 127 174501). By performing extensive event-driven molecular dynamics simulations, we monitor the dynamics of the system, locating the iso-diffusivity lines in the phase diagram, and discuss their location with respect to the gas-liquid phase separation. We observe the formation of an ideal gel which continuously crosses towards an attractive glass upon increasing the density. Moreover, we evaluate the statistical properties of the potential energy landscape for this model. We find that the configurational entropy, for densities within the optimal network-forming region, is finite even in the ground state and obeys a logarithmic dependence on the energy.

Nanoscale tissue engineering: spatial control over cell-materials interactions

Science.gov (United States)

Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G.; Jabbari, Esmaiel; Khademhosseini, Ali

2011-01-01

Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness the interactions through nanoscale biomaterials engineering in order to study and direct cellular behaviors. Here, we review the nanoscale tissue engineering technologies for both two- and three-dimensional studies (2- and 3D), and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffolds technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D, however, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and the temporal changes in cellular microenvironment. PMID:21451238

The Interaction between Negative Emotionality and Effortful Control in Early

Science.gov (United States)

Moran, Lyndsey R.; Lengua, Liliana J.; Zalewski, Maureen

2013-01-01

Interactions between reactive and regulatory dimensions of temperament may be particularly relevant to children's adjustment but are examined infrequently. This study investigated these interactions by examining effortful control as a moderator of the relations of fear and frustration reactivity to children's social competence, internalizing, and…

Interaction control of a redundant mobile manipulator

International Nuclear Information System (INIS)

Chung, J.H.; Velinsky, S.A.; Hess, R.A.

1998-01-01

This paper discusses the modeling and control of a spatial mobile manipulator that consists of a robotic manipulator mounted on a wheeled mobile platform. The Lagrange-d'Alembert formulation is used to obtain a concise description of the dynamics of the system, which is subject to nonholonomic constraints. The complexity of the model is increased by introducing kinematic redundancy, which is created when a multilinked manipulator is used. The kinematic redundancy is resolved by decomposing the mobile manipulator into two subsystems: the mobile platform and the manipulator. The redundancy resolution scheme employs a nonlinear interaction-control algorithm, which is developed and applied to coordinate the two subsystems' controllers. The subsystem controllers are independently designed, based on each subsystem's dynamic characteristics. Simulation results show the promise of the developed algorithm

Tailored long range forces on polarizable particles by collective scattering of broadband radiation

International Nuclear Information System (INIS)

Holzmann, D; Ritsch, H

2016-01-01

Collective coherent light scattering by polarizable particles creates surprisingly strong, long range inter-particle forces originating from interference of the light scattered by different particles. While for monochromatic laser beams this interaction decays with the inverse distance, we show here that in general the effective interaction range and geometry can be controlled by the illumination bandwidth and geometry. As generic example we study the modifications inter-particle forces within a 1D chain of atoms trapped in the field of a confined optical nanofiber mode. For two particles we find short range attraction as well as optical binding at multiple distances. The range of stable distances shrinks with increasing light bandwidth and for a very large bandwidth field as e.g. blackbody radiation. We find a strongly attractive potential up to a critical distance beyond which the force gets repulsive. Including multiple scattering can even lead to the appearance of a stable configuration at a large distance. Such broadband scattering forces should be observable contributions in ultra-cold atom interferometers or atomic clocks setups. They could be studied in detail in 1D geometries with ultra-cold atoms trapped along or within an optical nanofiber. Broadband radiation force interactions might also contribute in astrophysical scenarios as illuminated cold dust clouds. (paper)

Interactive TV: Interaction and Control in Second-screen TV Consumption

DEFF Research Database (Denmark)

Fleury, Alexandre; Pedersen, Jakob Schou; Baunstrup, Mai

2012-01-01

The integration of television and mobile technologies are becoming a reality in today’s home media environments. In order to facilitate the development of future cross-platform broadcast TV services, this study investigated prompting and control strategies for a secondary device in front of the TV...... they preferred with which content. Overall, we found a clear preference for keeping interactive contents and prompting on the secondary device and broadcast TV content on the primary screen. The workshops generated numerous ideas concerning possible personalization of such service....

Control-structure interaction in precision pointing servo loops

Science.gov (United States)

Spanos, John T.

1989-01-01

The control-structure interaction problem is addressed via stability analysis of a generic linear servo loop model. With the plant described by the rigid body mode and a single elastic mode, structural flexibility is categorized into one of three types: (1) appendage, (2) in-the-loop minimum phase, and (3) in-the-loop nonminimum phase. Closing the loop with proportional-derivative (PD) control action and introducing sensor roll-off dynamics in the feedback path, stability conditions are obtained. Trade studies are conducted with modal frequency, modal participation, modal damping, loop bandwidth, and sensor bandwidth treated as free parameters. Results indicate that appendage modes are most likely to produce instability if they are near the sensor rolloff, whereas in-the-loop modes are most dangerous near the loop bandwidth. The main goal of this paper is to provide a fundamental understanding of the control-structure interaction problem so that it may benefit the design of complex spacecraft and pointing system servo loops. In this framework, the JPL Pathfinder gimbal pointer is considered as an example.

Tools for controlling protein interactions with light

Science.gov (United States)

Tucker, Chandra L.; Vrana, Justin D.; Kennedy, Matthew J.

2014-01-01

Genetically-encoded actuators that allow control of protein-protein interactions with light, termed ‘optical dimerizers’, are emerging as new tools for experimental biology. In recent years, numerous new and versatile dimerizer systems have been developed. Here we discuss the design of optical dimerizer experiments, including choice of a dimerizer system, photoexcitation sources, and coordinate use of imaging reporters. We provide detailed protocols for experiments using two dimerization systems we previously developed, CRY2/CIB and UVR8/UVR8, for use controlling transcription, protein localization, and protein secretion with light. Additionally, we provide instructions and software for constructing a pulse-controlled LED light device for use in experiments requiring extended light treatments. PMID:25181301

Control system design and analysis using the INteractive Controls Analysis (INCA) program

Science.gov (United States)

Bauer, Frank H.; Downing, John P.

1987-01-01

The INteractive Controls Analysis (INCA) program was developed at the Goddard Space Flight Center to provide a user friendly efficient environment for the design and analysis of linear control systems. Since its inception, INCA has found extensive use in the design, development, and analysis of control systems for spacecraft, instruments, robotics, and pointing systems. Moreover, the results of the analytic tools imbedded in INCA have been flight proven with at least three currently orbiting spacecraft. This paper describes the INCA program and illustrates, using a flight proven example, how the package can perform complex design analyses with relative ease.

Controlling Correlated Tunneling and Superexchange Interactions with ac-Driven Optical Lattices

International Nuclear Information System (INIS)

Chen, Yu-Ao; Nascimbene, Sylvain; Aidelsburger, Monika; Atala, Marcos; Trotzky, Stefan; Bloch, Immanuel

2011-01-01

The dynamical control of tunneling processes of single particles plays a major role in science ranging from Shapiro steps in Josephson junctions to the control of chemical reactions via light in molecules. Here we show how such control can be extended to the regime of correlated tunneling of strongly interacting particles. Through a periodic modulation of a biased tunnel contact, we have been able to coherently control single-particle and correlated two-particle hopping processes. We have furthermore been able to extend this control to superexchange spin interactions in the presence of a magnetic-field gradient. Such photon-assisted superexchange processes constitute a novel approach to realize arbitrary XXZ spin models in ultracold quantum gases, where transverse and Ising-type spin couplings can be fully controlled in magnitude and sign.

Messaging Performance of FIPA Interaction Protocols in Networked Embedded Controllers

Directory of Open Access Journals (Sweden)

García JoséAPérez

2008-01-01

Full Text Available Abstract Agent-based technologies in production control systems could facilitate seamless reconfiguration and integration of mechatronic devices/modules into systems. Advances in embedded controllers which are continuously improving computational capabilities allow for software modularization and distribution of decisions. Agent platforms running on embedded controllers could hide the complexity of bootstrap and communication. Therefore, it is important to investigate the messaging performance of the agents whose main motivation is the resource allocation in manufacturing systems (i.e., conveyor system. The tests were implemented using the FIPA-compliant JADE-LEAP agent platform. Agent containers were distributed through networked embedded controllers, and agents were communicating using request and contract-net FIPA interaction protocols. The test scenarios are organized in intercontainer and intracontainer communications. The work shows the messaging performance for the different test scenarios using both interaction protocols.

Messaging Performance of FIPA Interaction Protocols in Networked Embedded Controllers

Directory of Open Access Journals (Sweden)

Omar Jehovani López Orozco

2007-12-01

Full Text Available Agent-based technologies in production control systems could facilitate seamless reconfiguration and integration of mechatronic devices/modules into systems. Advances in embedded controllers which are continuously improving computational capabilities allow for software modularization and distribution of decisions. Agent platforms running on embedded controllers could hide the complexity of bootstrap and communication. Therefore, it is important to investigate the messaging performance of the agents whose main motivation is the resource allocation in manufacturing systems (i.e., conveyor system. The tests were implemented using the FIPA-compliant JADE-LEAP agent platform. Agent containers were distributed through networked embedded controllers, and agents were communicating using request and contract-net FIPA interaction protocols. The test scenarios are organized in intercontainer and intracontainer communications. The work shows the messaging performance for the different test scenarios using both interaction protocols.

Control over position, orientation, and spacing of arrays of gold nanorods using chemically nanopatterned surfaces and tailored particle-particle-surface interactions.

Science.gov (United States)

Nepal, Dhriti; Onses, M Serdar; Park, Kyoungweon; Jespersen, Michael; Thode, Christopher J; Nealey, Paul F; Vaia, Richard A

2012-06-26

The synergy of self- and directed-assembly processes and lithography provides intriguing avenues to fabricate translationally ordered nanoparticle arrangements, but currently lacks the robustness necessary to deliver complex spatial organization. Here, we demonstrate that interparticle spacing and local orientation of gold nanorods (AuNR) can be tuned by controlling the Debye length of AuNR in solution and the dimensions of a chemical contrast pattern. Electrostatic and hydrophobic selectivity for AuNR to absorb to patterned regions of poly(2-vinylpyridine) (P2VP) and polystyrene brushes and mats was demonstrated for AuNR functionalized with mercaptopropane sulfonate (MS) and poly(ethylene glycol), respectively. For P2VP patterns of stripes with widths comparable to the length of the AuNR, single- and double-column arrangements of AuNR oriented parallel and perpendicular to the P2VP line were obtained for MS-AuNR. Furthermore, the spacing of the assembled AuNR was uniform along the stripe and related to the ionic strength of the AuNR dispersion. The different AuNR arrangements are consistent with predictions based on maximization of packing of AuNR within the confined strip.

Control configuration selection for bilinear systems via generalised Hankel interaction index array

DEFF Research Database (Denmark)

Shaker, Hamid Reza; Tahavori, Maryamsadat

2015-01-01

configuration selection. It is well known that a suitable control configuration selection is an important prerequisite for a successful industrial control. In this paper the problem of control configuration selection for multiple-input and multiple-output (MIMO) bilinear processes is addressed. First...... way, an iterative method for solving the generalised Sylvester equation is proposed. The generalised cross-gramian is used to form the generalised Hankel interaction index array. The generalised Hankel interaction index array is used for control configuration selection of MIMO bilinear processes. Most......Decentralised and partially decentralised control strategies are very popular in practice. To come up with a suitable decentralised or partially decentralised control structure, it is important to select the appropriate input and output pairs for control design. This procedure is called control...

Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

International Nuclear Information System (INIS)

Gon Corradini, Patricia; Pires, Felipe I.; Paganin, Valdecir A.; Perez, Joelma; Antolini, Ermete

2012-01-01

The effect of the relationship between particle size (d), inter-particle distance (x i ), and metal loading (y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5–3 nm) and x i /d (>5) values, was evaluated. It was found that for y i /d can be always obtained. For y ≥ 30 wt%, instead, the positive effect of a thinner catalyst layer of the fuel cell electrode than that using catalysts with y i /d compared to their optimum values, with in turns gives rise to a decrease in the catalytic activity. The effect of the x i /d ratio has been successfully verified by experimental results on ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x i /d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.

rpanel: Simple Interactive Controls for R Functions Using the tcltk Package

Directory of Open Access Journals (Sweden)

Gavin Alexander

2006-01-01

Full Text Available In a variety of settings it is extremely helpful to be able to apply R functions through buttons, sliders and other types of graphical control. This is particularly true in plotting activities where immediate communication between such controls and a graphical display allows the user to interact with a plot in a very effective manner. The tcltk package provides extensive tools for this and the aim of the rpanel package is to provide simple and well documented functions which make these facilities as accessible as possible. In addition, the operations which form the basis of communication within tcltk are managed in a way which allows users to write functions with a more standard form of parameter passing. This paper describes the basic design of the software and illustrates it on a variety of examples of interactive control of graphics. The tkrplot system is used to allow plots to be integrated with controls into a single panel. An example of the use of a graphical image, and the ability to interact with this, is also discussed.

Tools for Trustworthy Autonomy: Robust Predictions, Intuitive Control, and Optimized Interaction

OpenAIRE

Driggs Campbell, Katherine Rose

2017-01-01

In the near future, robotics will impact nearly every aspect of life. Yet for technology to smoothly integrate into society, we need interactive systems to be well modeled and predictable; have robust decision making and control; and be trustworthy to improve cooperation and interaction. To achieve these goals, we propose taking a human-centered approach to ease the transition into human-dominated fields. In this work, our modeling methods and control schemes are validated through user stu...

INCA- INTERACTIVE CONTROLS ANALYSIS

Science.gov (United States)

Bauer, F. H.

1994-01-01

The Interactive Controls Analysis (INCA) program was developed to provide a user friendly environment for the design and analysis of linear control systems, primarily feedback control systems. INCA is designed for use with both small and large order systems. Using the interactive graphics capability, the INCA user can quickly plot a root locus, frequency response, or time response of either a continuous time system or a sampled data system. The system configuration and parameters can be easily changed, allowing the INCA user to design compensation networks and perform sensitivity analysis in a very convenient manner. A journal file capability is included. This stores an entire sequence of commands, generated during an INCA session into a file which can be accessed later. Also included in INCA are a context-sensitive help library, a screen editor, and plot windows. INCA is robust to VAX-specific overflow problems. The transfer function is the basic unit of INCA. Transfer functions are automatically saved and are available to the INCA user at any time. A powerful, user friendly transfer function manipulation and editing capability is built into the INCA program. The user can do all transfer function manipulations and plotting without leaving INCA, although provisions are made to input transfer functions from data files. By using a small set of commands, the user may compute and edit transfer functions, and then examine these functions by using the ROOT_LOCUS, FREQUENCY_RESPONSE, and TIME_RESPONSE capabilities. Basic input data, including gains, are handled as single-input single-output transfer functions. These functions can be developed using the function editor or by using FORTRAN- like arithmetic expressions. In addition to the arithmetic functions, special functions are available to 1) compute step, ramp, and sinusoid functions, 2) compute closed loop transfer functions, 3) convert from S plane to Z plane with optional advanced Z transform, and 4) convert from Z

Bio-Inspired Interaction Control of Robotic Machines for Motor Therapy

OpenAIRE

Zollo, Loredana; Formica, Domenico; Guglielmelli, Eugenio

2007-01-01

In this chapter basic criteria for the design and implementation of interaction control of robotic machines for motor therapy have been briefly introduced and two bio-inspired compliance control laws developed by the authors to address requirements coming from this specific application field have been presented. The two control laws are named the coactivation-based compliance control in the joint space and the torque-dependent compliance control in the joint space, respectively. They try to o...

RHEOLOGY AND SCALING BEHAVIOR OF SWELLING CLAY DISPERSIONS

Directory of Open Access Journals (Sweden)

S. Chaoui

2015-07-01

Full Text Available The microstructure and scaling of rheological properties of colloidal gels of bentonite investigated as a function of volume fraction and strength of interparticle interaction over a range of volume fractions, elastic modulus is well described with a scaling law functions of volume fractions, while the role of interparticle attractions can be accounted for by expressing these rheological properties as (f/fg-1n, where fg captures the strength of particle interaction and n the microstructure. The scaling variable (fp/fpc-1, suggested in percolation theory to describe rheological behavior near percolation transition, acts to collapse G’ data suggesting that along lines of constant (f/fg-1 these gels are rheologically identical.

RHEOLOGY AND SCALING BEHAVIOR OF SWELLING CLAY DISPERSIONS

Directory of Open Access Journals (Sweden)

S. CHAOUI

2012-12-01

Full Text Available The microstructure and scaling of rheological properties of colloidal gels of bentonite investigated as a function of volume fraction and strength of interparticle interaction over a range of volume fractions, elastic modulus is well described with a scaling law functions of volume fractions, while the role of interparticle attractions can be accounted for by expressing these rheological properties as (/g-1n, where g captures the strength of particle interaction and n the microstructure.The scaling variable (p/pc-1, suggested in percolation theory to describe rheological behavior near percolation transition, acts to collapse G’ data suggesting that along lines of constant (/g-1 these gels are rheologically identical.

The self-consistent field model for Fermi systems with account of three-body interactions

Directory of Open Access Journals (Sweden)

Yu.M. Poluektov

2015-12-01

Full Text Available On the basis of a microscopic model of self-consistent field, the thermodynamics of the many-particle Fermi system at finite temperatures with account of three-body interactions is built and the quasiparticle equations of motion are obtained. It is shown that the delta-like three-body interaction gives no contribution into the self-consistent field, and the description of three-body forces requires their nonlocality to be taken into account. The spatially uniform system is considered in detail, and on the basis of the developed microscopic approach general formulas are derived for the fermion's effective mass and the system's equation of state with account of contribution from three-body forces. The effective mass and pressure are numerically calculated for the potential of "semi-transparent sphere" type at zero temperature. Expansions of the effective mass and pressure in powers of density are obtained. It is shown that, with account of only pair forces, the interaction of repulsive character reduces the quasiparticle effective mass relative to the mass of a free particle, and the attractive interaction raises the effective mass. The question of thermodynamic stability of the Fermi system is considered and the three-body repulsive interaction is shown to extend the region of stability of the system with the interparticle pair attraction. The quasiparticle energy spectrum is calculated with account of three-body forces.

Controlled growth of Ni/NiO core–shell nanoparticles: Structure, morphology and tuning of magnetic properties

Energy Technology Data Exchange (ETDEWEB)

D’Addato, S., E-mail: sergio.daddato@unimore.it [CNR-NANO, S3, via G. Campi 213/a, Modena (Italy); Dipartimento FIM, Università di Modena e Reggio Emilia, via G. Campi 213/a, Modena (Italy); Spadaro, M.C. [CNR-NANO, S3, via G. Campi 213/a, Modena (Italy); Dipartimento FIM, Università di Modena e Reggio Emilia, via G. Campi 213/a, Modena (Italy); Luches, P. [CNR-NANO, S3, via G. Campi 213/a, Modena (Italy); Grillo, V. [CNR-NANO, S3, via G. Campi 213/a, Modena (Italy); CNR-IMEM, Parco Area delle Scienze 37/A, 43100 Parma (Italy); Frabboni, S.; Valeri, S. [CNR-NANO, S3, via G. Campi 213/a, Modena (Italy); Dipartimento FIM, Università di Modena e Reggio Emilia, via G. Campi 213/a, Modena (Italy); Ferretti, A.M.; Capetti, E.; Ponti, A. [CNR-ISTM, Laboratorio di Nanotecnologie, via G. Fantoli 16/15, 20138 Milano (Italy)

2014-07-01

We performed a detailed study of Ni/NiO core–shell nanoparticles (NP) obtained with a gas aggregation source. The NP oxide shells were produced by oxidizing the NP with different procedures: deposition in oxygen atmosphere, post-annealing in air, sequential deposition of (a) first NiO layer, (b) Ni NP and (c) third NiO Layer. X-ray photoelectron spectroscopy from Ni 2p core-level gave information about the chemical state of Ni in the core and in the oxide shell, while scanning electron microscopy was used for investigation of the NP morphology. High quality scanning transmission electron microscopy in high angle annular dark field mode data demonstrated core–shell structure also for NiO/Ni NP/NiO samples. Field-cooled/zero-field-cooled magnetization curves and field-cooled isothermal hysteresis cycles at T = 5 K were recorded by a SQUID magnetometer. In this way, the relation between magnetic properties and oxide shell structure was assessed, showing the role played by the control of the formation of oxide on the exchange bias and interparticle magnetic interaction.

Controlled growth of Ni/NiO core–shell nanoparticles: Structure, morphology and tuning of magnetic properties

International Nuclear Information System (INIS)

D’Addato, S.; Spadaro, M.C.; Luches, P.; Grillo, V.; Frabboni, S.; Valeri, S.; Ferretti, A.M.; Capetti, E.; Ponti, A.

2014-01-01

We performed a detailed study of Ni/NiO core–shell nanoparticles (NP) obtained with a gas aggregation source. The NP oxide shells were produced by oxidizing the NP with different procedures: deposition in oxygen atmosphere, post-annealing in air, sequential deposition of (a) first NiO layer, (b) Ni NP and (c) third NiO Layer. X-ray photoelectron spectroscopy from Ni 2p core-level gave information about the chemical state of Ni in the core and in the oxide shell, while scanning electron microscopy was used for investigation of the NP morphology. High quality scanning transmission electron microscopy in high angle annular dark field mode data demonstrated core–shell structure also for NiO/Ni NP/NiO samples. Field-cooled/zero-field-cooled magnetization curves and field-cooled isothermal hysteresis cycles at T = 5 K were recorded by a SQUID magnetometer. In this way, the relation between magnetic properties and oxide shell structure was assessed, showing the role played by the control of the formation of oxide on the exchange bias and interparticle magnetic interaction.

Discrete element analysis of the mechanical properties of deep-sea methane hydrate-bearing soils considering interparticle bond thickness

Science.gov (United States)

Jiang, Mingjing; He, Jie; Wang, Jianfeng; Zhou, Yaping; Zhu, Fangyuan

2017-12-01

Due to increasing global energy demands, research is being conducted on the mechanical properties of methane hydrate-bearing soils (MHBSs), from which methane hydrate (MH) will be explored. This paper presents a numerical approach to study the mechanical properties of MHBSs. The relationship between the level of MH saturation and the interparticle bond thickness is first obtained by analyzing the scanning electron microscope images of MHBS samples, in which is the bridge connecting the micromechanical behavior captured by the DEM with the macroscopic properties of MHBSs. A simplified thermal-hydromechanical (THM) bond model that considers the different bond thicknesses is then proposed to describe the contact behavior between the soil particles and those incorporated into the discrete element method (DEM). Finally, a series of biaxial compression tests are carried out with different MH saturations under different effective confining pressures to analyze the mechanical properties of deep-sea MHBSs. The results of the DEM numerical simulation are also compared with the findings from triaxial compression tests. The results show that the macromechanical properties of deep-sea MHBSs can be qualitatively captured by the proposed DEM. The shear strength, cohesion, and volumetric contraction of deep-sea MHBSs increase with increasing MH saturation, although its influence on the internal friction angle is obscure. The shear strength and volumetric contraction increase with increasing effective confining pressure. The peak shear strength and the dilation of MHBSs increase as the critical bond thickness increases, while the residual deviator stress largely remains the same at a larger axial strain. With increasing the axial strain, the percentage of broken bonds increases, along with the expansion of the shear band.

Automated boundary interaction force control of micromanipulators with in situ applications to microsurgery

International Nuclear Information System (INIS)

Eslami, Sohrab; Jalili, Nader

2012-01-01

Most recent works on miniature tasks are concentrated on developing tools to take advantage of the visual servoing feedback to control the ultra-small interaction forces. This paper spans an extensive platform for automatic controlling of boundary interaction forces with high precision in the level of micro/nano-Newton with extensive micro/nanoengineering applications such as the microsurgery. To this end, a comprehensive piezoresistive microcantilever (PMC) model considering the shear deformation and rotary inertia effects treating as the distributed-parameters model along with the Hertzian contact force is presented. The purpose of considering the Hertzian contact force model is to investigate the dynamic response of the interaction force between the microcantilever's tip and the specimen. Afterward, a control platform is introduced to automatically manipulate the PMC to follow an ideal micro/nano-interaction force. By using the integrated PMC with the micromanipulator and a digital signal processor, an intuitive programming code is written to incorporate the micromanipulator and the controller in a real-time framework. To calibrate and verify the induced voltage in the PMC, a self-sensing experiment on the piezoelectric microcantilever is carried out to warrant the calibration procedure. Some experiments are established to affirm the validity of the proposed control for the autonomous real-time tasks on the boundary interaction force control. Unlike the conventional research studies, the measured force here contributes as the feedback source in contrast to the vision feedback while force sensors possess more precision, productivity and small size. This technique has several potential applications listed but not limited to the micro/nanomanipulation, developing artificial biological systems (e.g., fabricating hydrogel for the scaffold), and medicine such as microsurgery. As a result, using the proposed platform, we are able to manipulate and control the

Simulation of Fuzzy Adaptive PI Controlled Grid Interactive Inverter

Directory of Open Access Journals (Sweden)

Necmi ALTIN

2009-03-01

Full Text Available In this study, a voltage source grid interactive inverter is modeled and simulated in MATLAB/Simulink. Inverter is designed as current controlled and a fuzzy-PI current controller used for the generation of switching pattern to shape the inverter output current. The grid interactive inverter consists of a line frequency transformer and a LC type filter. Galvanic isolation between the grid and renewable energy source is obtained by the line frequency transformer and LC filter is employed to filter the high frequency harmonic components in current waveform due to PWM switching and to reduce the output current THD. Results of the MATLAB/Simulink simulation show that inverter output current is in sinusoidal waveform and in phase with line voltage, and current harmonics are in the limits of international standards (

The interaction of amylin with other hormones in the control of eating.

Science.gov (United States)

Lutz, T A

2013-02-01

Twenty years of research established amylin as an important control of energy homeostasis. Amylin controls nutrient and energy fluxes by reducing energy intake, by modulating nutrient utilization via an inhibition of postprandial glucagon secretion and by increasing energy disposal via a prevention of compensatory decreases of energy expenditure in weight reduced individuals. Like many other gastrointestinal hormones, amylin is secreted in response to meals and it reduces eating by promoting meal-ending satiation. Not surprisingly, amylin interacts with many of these hormones to control eating. These interactions seem to occur at different levels because amylin seems to mediate the eating inhibitory effect of some of these gastrointestinal hormones, and the combination of some of these hormones seems to lead to a stronger reduction in eating than single hormones alone. Amylin's effect on eating is thought to be mediated by a stimulation of specific amylin receptors in the area postrema. Secondary brain sites that were defined to mediate amylin action - and hence potential additional sites of interaction with other hormones - include the nucleus of the solitary tract, the lateral parabrachial nucleus, the lateral hypothalamic area and other hypothalamic nuclei. The focus of this review is to summarize the current knowledge of amylin interactions in the control of eating. In most cases, these interactions have only been studied at a descriptive rather than a mechanistic level and despite the clear knowledge on primary sites of amylin action, the interaction sites between amylin and other hormones are often unknown. © 2012 Blackwell Publishing Ltd.

Interactive computer graphics and its role in control system design of large space structures

Science.gov (United States)

Reddy, A. S. S. R.

1985-01-01

This paper attempts to show the relevance of interactive computer graphics in the design of control systems to maintain attitude and shape of large space structures to accomplish the required mission objectives. The typical phases of control system design, starting from the physical model such as modeling the dynamics, modal analysis, and control system design methodology are reviewed and the need of the interactive computer graphics is demonstrated. Typical constituent parts of large space structures such as free-free beams and free-free plates are used to demonstrate the complexity of the control system design and the effectiveness of the interactive computer graphics.

Is the Pauli exclusion principle the origin of electron localisation?

Science.gov (United States)

Rincón, Luis; Torres, F. Javier; Almeida, Rafael

2018-03-01

In this work, we inquire into the origins of the electron localisation as obtained from the information content of the same-spin pair density, γσ, σ(r2∣r1). To this end, we consider systems of non-interacting and interacting identical Fermions contained in two simple 1D potential models: (1) an infinite potential well and (2) the Kronig-Penney periodic potential. The interparticle interaction is considered through the Hartree-Fock approximation as well as the configuration interaction expansion. Morover, the electron localisation is described through the Kullback-Leibler divergence between γσ, σ(r2∣r1) and its associated marginal probability. The results show that, as long as the adopted method properly includes the Pauli principle, the electronic localisation depends only modestly on the interparticle interaction. In view of the latter, one may conclude that the Pauli principle is the main responsible for the electron localisation.

Action and reaction in the theories of direct interparticle action

International Nuclear Information System (INIS)

Narlikar, J.V.

1975-01-01

Newton's third law of motion is examined in the context of the theories of direct interpaticle action. In such theories, interactions between particles travel backward and forward in time at speeds not exceeding the speed of light. It is shown that while in the flat spacetime the equality of action and reaction can be clearly demonstrated, the situation is considerably more complicated in the curved spacetime. The phenomenon of gravitational scattering intervenes to destroy the equality of action and reaction. Nevertheless, when gravitation is taken into account, there is no violation of the conservation law of energy and momentum. These results are discussed in the framework of general relativity for the case of the electromagnetic interaction

The role of interactive control systems in obtaining internal consistency in the management control system package

DEFF Research Database (Denmark)

Toldbod, Thomas; Israelsen, Poul

2014-01-01

Companies rely on multiple Management Control Systems to obtain their short and long term objectives. When applying a multifaceted perspective on Management Control System the concept of internal consistency has been found to be important in obtaining goal congruency in the company. However, to d...... management is aware of this shortcoming they use the cybernetic controls more interactively to overcome this shortcoming, whereby the cybernetic controls are also used as a learning platform and not just for performance control....

Local thermodynamics and the generalized Gibbs-Duhem equation in systems with long-range interactions.

Science.gov (United States)

Latella, Ivan; Pérez-Madrid, Agustín

2013-10-01

The local thermodynamics of a system with long-range interactions in d dimensions is studied using the mean-field approximation. Long-range interactions are introduced through pair interaction potentials that decay as a power law in the interparticle distance. We compute the local entropy, Helmholtz free energy, and grand potential per particle in the microcanonical, canonical, and grand canonical ensembles, respectively. From the local entropy per particle we obtain the local equation of state of the system by using the condition of local thermodynamic equilibrium. This local equation of state has the form of the ideal gas equation of state, but with the density depending on the potential characterizing long-range interactions. By volume integration of the relation between the different thermodynamic potentials at the local level, we find the corresponding equation satisfied by the potentials at the global level. It is shown that the potential energy enters as a thermodynamic variable that modifies the global thermodynamic potentials. As a result, we find a generalized Gibbs-Duhem equation that relates the potential energy to the temperature, pressure, and chemical potential. For the marginal case where the power of the decaying interaction potential is equal to the dimension of the space, the usual Gibbs-Duhem equation is recovered. As examples of the application of this equation, we consider spatially uniform interaction potentials and the self-gravitating gas. We also point out a close relationship with the thermodynamics of small systems.

Large Display Interaction via Multiple Acceleration Curves and Multifinger Pointer Control

Directory of Open Access Journals (Sweden)

Andrey Esakia

2014-01-01

Full Text Available Large high-resolution displays combine high pixel density with ample physical dimensions. The combination of these factors creates a multiscale workspace where interactive targeting of on-screen objects requires both high speed for distant targets and high accuracy for small targets. Modern operating systems support implicit dynamic control-display gain adjustment (i.e., a pointer acceleration curve that helps to maintain both speed and accuracy. However, large high-resolution displays require a broader range of control-display gains than a single acceleration curve can usably enable. Some interaction techniques attempt to solve the problem by utilizing multiple explicit modes of interaction, where different modes provide different levels of pointer precision. Here, we investigate the alternative hypothesis of using a single mode of interaction for continuous pointing that enables both (1 standard implicit granularity control via an acceleration curve and (2 explicit switching between multiple acceleration curves in an efficient and dynamic way. We evaluate a sample solution that augments standard touchpad accelerated pointer manipulation with multitouch capability, where the choice of acceleration curve dynamically changes depending on the number of fingers in contact with the touchpad. Specifically, users can dynamically switch among three different acceleration curves by using one, two, or three fingers on the touchpad.

Air pollution control technologies and their interactions

Energy Technology Data Exchange (ETDEWEB)

Nalbandian, H. [IEA Clean Coal Centre, London (United Kingdom)

2004-11-01

A large number of coal-fired power stations have been fitted/retrofitted with dedicated air pollutant control technologies. Experience shows that these technologies can have complex interactions and can impact each other as well as balance of plant, positively and/or negatively. Particulate matter (PM) is usually captured with electrostatic precipitators (ESPs) and fabric filters (FF). These technologies are efficient and reliable but their performance may be affected by modifying operating conditions and introducing primary measures for NOx reduction. Flue gas desulphurisation (FGD) systems for SO{sub 2} control have been installed in many facilities with the most popular technology being the wet limestone/gypsum scrubber. FGD use can decrease particulate matter and mercury emissions which is a major issue in the USA, cause an increase in carbon dioxide emissions, and in solids by-product. Primary measures such as low NOx burners (LNBs) and overfire air (OFA) minimise NOx formation but can increase carbon in ash (CIA) which can cause problems with fly ash sales but may also improve mercury capture. Reducing NOx emissions with selective catalytic reduction (SCR) can result in a decrease in particulate matter, an increase in SO{sub 3} emissions and trace increase in NH{sub 3}. This can cause fouling and loss of performance of the air preheater, due to the formation of ammonium sulphates. One way of alleviating this is improved soot-blowing and other cleaning capabilities. This report studies these and other interactions between existing air pollution control technologies in pulverised coal fired power plants. 249 refs., 13 figs., 18 tabs.

Well-Controlled Cell-Trapping Systems for Investigating Heterogeneous Cell-Cell Interactions.

Science.gov (United States)

Kamiya, Koki; Abe, Yuta; Inoue, Kosuke; Osaki, Toshihisa; Kawano, Ryuji; Miki, Norihisa; Takeuchi, Shoji

2018-03-01

Microfluidic systems have been developed for patterning single cells to study cell-cell interactions. However, patterning multiple types of cells to understand heterogeneous cell-cell interactions remains difficult. Here, it is aimed to develop a cell-trapping device to assemble multiple types of cells in the well-controlled order and morphology. This device mainly comprises a parylene sheet for assembling cells and a microcomb for controlling the cell-trapping area. The cell-trapping area is controlled by moving the parylene sheet on an SU-8 microcomb using tweezers. Gentle downward flow is used as a driving force for the cell-trapping. The assembly of cells on a parylene sheet with round and line-shaped apertures is demonstrated. The cell-cell contacts of the trapped cells are then investigated by direct cell-cell transfer of calcein via connexin nanopores. Finally, using the device with a system for controlling the cell-trapping area, three different types of cells in the well-controlled order are assembled. The correct cell order rate obtained using the device is 27.9%, which is higher than that obtained without the sliding parylene system (0.74%). Furthermore, the occurrence of cell-cell contact between the three cell types assembled is verified. This cell-patterning device will be a useful tool for investigating heterogeneous cell-cell interactions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pair correlation function decay in models of simple fluids that contain dispersion interactions.

Science.gov (United States)

Evans, R; Henderson, J R

2009-11-25

We investigate the intermediate-and longest-range decay of the total pair correlation function h(r) in model fluids where the inter-particle potential decays as -r(-6), as is appropriate to real fluids in which dispersion forces govern the attraction between particles. It is well-known that such interactions give rise to a term in q(3) in the expansion of [Formula: see text], the Fourier transform of the direct correlation function. Here we show that the presence of the r(-6) tail changes significantly the analytic structure of [Formula: see text] from that found in models where the inter-particle potential is short ranged. In particular the pure imaginary pole at q = iα(0), which generates monotonic-exponential decay of rh(r) in the short-ranged case, is replaced by a complex (pseudo-exponential) pole at q = iα(0)+α(1) whose real part α(1) is negative and generally very small in magnitude. Near the critical point α(1)∼-α(0)(2) and we show how classical Ornstein-Zernike behaviour of the pair correlation function is recovered on approaching the mean-field critical point. Explicit calculations, based on the random phase approximation, enable us to demonstrate the accuracy of asymptotic formulae for h(r) in all regions of the phase diagram and to determine a pseudo-Fisher-Widom (pFW) line. On the high density side of this line, intermediate-range decay of rh(r) is exponentially damped-oscillatory and the ultimate long-range decay is power-law, proportional to r(-6), whereas on the low density side this damped-oscillatory decay is sub-dominant to both monotonic-exponential and power-law decay. Earlier analyses did not identify the pseudo-exponential pole and therefore the existence of the pFW line. Our results enable us to write down the generic wetting potential for a 'real' fluid exhibiting both short-ranged and dispersion interactions. The monotonic-exponential decay of correlations associated with the pseudo-exponential pole introduces additional terms into

Control of a Robot Dancer for Enhancing Haptic Human-Robot Interaction in Waltz.

Science.gov (United States)

Hongbo Wang; Kosuge, K

2012-01-01

Haptic interaction between a human leader and a robot follower in waltz is studied in this paper. An inverted pendulum model is used to approximate the human's body dynamics. With the feedbacks from the force sensor and laser range finders, the robot is able to estimate the human leader's state by using an extended Kalman filter (EKF). To reduce interaction force, two robot controllers, namely, admittance with virtual force controller, and inverted pendulum controller, are proposed and evaluated in experiments. The former controller failed the experiment; reasons for the failure are explained. At the same time, the use of the latter controller is validated by experiment results.

Large-eddy simulation of passive shock-wave/boundary-layer interaction control

International Nuclear Information System (INIS)

Pasquariello, Vito; Grilli, Muzio; Hickel, Stefan; Adams, Nikolaus A.

2014-01-01

Highlights: • The present study investigates a passive flow-control technique for shock-wave/boundary-layer interaction. • The control configuration consists of local suction and injection through a pressure feedback duct. • Implicit LES have been conducted for three different suction locations. • Suction reduces the size of the separation zone. • Turbulence amplification and reflected shock dynamics can be significantly reduced. - Abstract: We investigate a passive flow-control technique for the interaction of an oblique shock generated by an 8.8° wedge with a turbulent boundary-layer at a free-stream Mach number of Ma ∞ =2.3 and a Reynolds number based on the incoming boundary-layer thickness of Re δ 0 =60.5×10 3 by means of large-eddy simulation (LES). The compressible Navier–Stokes equations in conservative form are solved using the adaptive local deconvolution method (ALDM) for physically consistent subgrid scale modeling. Emphasis is placed on the correct description of turbulent inflow boundary conditions, which do not artificially force low-frequency periodic motion of the reflected shock. The control configuration combines suction inside the separation zone and blowing upstream of the interaction region by a pressure feedback through a duct embedded in the wall. We vary the suction location within the recirculation zone while the injection position is kept constant. Suction reduces the size of the separation zone with strongest effect when applied in the rear part of the separation bubble. The analysis of wall-pressure spectra reveals that all control configurations shift the high-energy low-frequency range to higher frequencies, while the energy level is significantly reduced only if suction acts in the rear part of the separated zone. In that case also turbulence production within the interaction region is significantly reduced as a consequence of mitigated reflected shock dynamics and near-wall flow acceleration

Coordination Chemistry Inside Polymeric Nanoreactors: Interparticle Metal Exchange and Ionic Compound Vectorization in Phosphine-Functionalized Amphiphilic Polymer Latexes.

Science.gov (United States)

Chen, Si; Gayet, Florence; Manoury, Eric; Joumaa, Ahmad; Lansalot, Muriel; D'Agosto, Franck; Poli, Rinaldo

2016-04-25

Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Neutron Time-of-Flight Quantification of Water Desorption Isotherms of Montmorillonite

DEFF Research Database (Denmark)

Gates, Will P.; Bordallo, Heloisa N.; Aldridge, Laurence P.

2012-01-01

enabled us to differentiate at least two water motions during dehydration of Ca- and Na-SAz-1 (initially equilibrated at RH = 55%) by using a "controlled water loss" time-of-flight procedure. This work confirms that (a) interlayer and cationic water in dioctahedral smectites are characterized by slower...... motions than interparticle water, (b) interlayer cations influenced the dynamics of water loss, probably through its affect on clay fabric, and (c) interparticle water behaves more like bulk water. At 55% RH the Ca montmorillonite held more interparticle water, but on dehydration under controlled......The multiple energy states of water held by surfaces of a clay mineral can be effectively probed with time-of-flight and fixed elastic window neutron scattering. We used these techniques to quantitatively differentiate water types, including rotational and translational diffusions, in Ca- and Na...

A unified grid current control for grid-interactive DG inverters in microgrids

DEFF Research Database (Denmark)

Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

2015-01-01

This paper proposes a unified grid current control for grid-interactive distributed generation inverters. In the approach, the grid-side current, instead of inverter-side current, is controlled as an inner loop, while the filter capacitor voltage is indirectly regulated through a virtual admittan...... locus analyses in the discrete z-domain are performed for elaborating the controller design. Simulations and experimental results demonstrate the performances of the proposed approach.......This paper proposes a unified grid current control for grid-interactive distributed generation inverters. In the approach, the grid-side current, instead of inverter-side current, is controlled as an inner loop, while the filter capacitor voltage is indirectly regulated through a virtual admittance...... in the outer loop. It, therefore, provides several superior features over traditional control schemes: 1) high-quality grid current in the grid-connected mode, 2) inherent derivative-less virtual output impedance control, and 3) the unified active damping for both grid-connected and islanded operations. Root...

3rd Symposium on Fluid-Structure-Sound Interactions and Control

CERN Document Server

Lucey, AD; Liu, Yang; Huang, Lixi

2016-01-01

These proceedings primarily focus on advances in the theory, experiments, and numerical simulations of turbulence in the contexts of flow-induced vibration and noise, as well as their control. Fluid-related structural vibration and noise problems are often encountered in many engineering fields, increasingly making them a cause for concern. The FSSIC conference, held on 5-9 July 2015 in Perth, featured prominent keynote speakers such as John Kim, Nigel Peake, Song Fu and Colin Hansen, as well as talks on a broad range of topics: turbulence, fluid-structure interaction, fluid-related noise and the control/management aspects of these research areas, many of which are clearly interdisciplinary in nature. It provided a forum for academics, scientists and engineers working in all branches of Fluid-Structure-Sound Interactions and Control (FSSIC) to exchange and share the latest developments, ideas and advances, bringing them together researchers from East and West to push forward the frontiers of FSSIC, ensuring t...

Structural orderings of anisotropically confined colloids interacting via a quasi-square-well potential.

Science.gov (United States)

Campos, L Q Costa; Apolinario, S W S

2015-01-01

We implement Brownian dynamics to investigate the static properties of colloidal particles confined anisotropically and interacting via a potential which can be tailored in a repulsive-attractive-respulsive fashion as the interparticle distance increases. A diverse number of structural phases are self-assembled, which were classified according to two aspects, that is, their macroscopic and microscopic patterns. Concerning the microscopic phases we found the quasicrystalline, triangular, square, and mixed orderings, where this latter is a combination of square and triangular cells in a 3×2 proportion, i.e., the so-called (3(3),4(2)) Archimedian lattice. On the macroscopic level the system could self-organize in a compact or perforated single cluster surrounded or not by fringes. All the structural phases are summarized in detailed phases diagrams, which clearly show that the different phases are extended as the confinement potential becomes more anisotropic.

Controlled Interactions between Two Dimensional Layered Inorganic Nanosheets and Polymers

Science.gov (United States)

2016-06-15

AFRL-AFOSR-JP-TR-2016-0071 Controlled Interactions between Two Dimensional Layered Inorganic Nanosheets and Polymers Cheolmin Park YONSEI UNIVERSITY...Interactions between Two Dimensional Layered Inorganic Nanosheets and Polymers 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-14-1-4054 5c.  PROGRAM ELEMENT...prospects for a variety of emerging applications in a broad range of fields, such as electronics, energy conversion and storage, catalysis and polymer

Particle attraction effects on the centrifugal casting and extrusion of alumina

International Nuclear Information System (INIS)

Schilling, C.H.; Bergstroem, L.; Ker, H.L.; Aksay, I.A.

1993-01-01

Interparticle attraction forces were empirically related to the centrifugal casting and extrusion behavior of flocculated alumina suspensions. Attractive forces were altered by two approaches: Salt flocculation, which entails regulating the electrical double-layer thickness through electrolyte additions; and screening of van der Waals attraction by steric interactions of surface-adsorbed fatty acids. Specimens produced by both compressibility at a critical maximum density that increased with decreasing interparticle attraction. Gradients in packing density during centrifugal casting were alleviated using both methods as long as spatial variations of the effective stress were within the low-compressibility range. We hypothesized that the reduced interparticle attraction in both methods may also raise the threshold packing density at which ductile-to-brittle transitions occur during plastic shear. Specimens prepared with oleic acid adlayers were highly plastic and easily extrudable at solids contents of up to 59 vol%, although salt-flocculated samples at 55 vol% density extruded at creeping flow rates that were insensitive to the applied pressure. Results suggested that particle rearrangement during shear, is a rate-limiting process, with an average relaxation time that is lowered by reducing interparticle attraction

Interaction Control Protocols for Distributed Multi-user Multi-camera Environments

Directory of Open Access Journals (Sweden)

Gareth W Daniel

2003-10-01

Full Text Available Video-centred communication (e.g., video conferencing, multimedia online learning, traffic monitoring, and surveillance is becoming a customary activity in our lives. The management of interactions in such an environment is a complicated HCI issue. In this paper, we present our study on a collection of interaction control protocols for distributed multiuser multi-camera environments. These protocols facilitate different approaches to managing a user's entitlement for controlling a particular camera. We describe a web-based system that allows multiple users to manipulate multiple cameras in varying remote locations. The system was developed using the Java framework, and all protocols discussed have been incorporated into the system. Experiments were designed and conducted to evaluate the effectiveness of these protocols, and to enable the identification of various human factors in a distributed multi-user and multi-camera environment. This work provides an insight into the complexity associated with the interaction management in video-centred communication. It can also serve as a conceptual and experimental framework for further research in this area.

Face-to-face interaction of multisolitons in spin-1/2 quantum plasma

Indian Academy of Sciences (India)

2016-12-13

Dec 13, 2016 ... tems [14]. When de Broglie wavelength of charge car- riers becomes comparable to the system scales (such as interparticle distances), the quantum effects should be taken into account. In quantum plasma, Fermi–. Dirac distribution is used to describe the system rather than Maxwell–Boltzmann distribution.

Reduction of Flight Control System/Structural Mode Interaction, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — A novel approach is proposed for reducing the degree of interaction of a high gain flight control system with the airframe structural vibration modes, representing a...

Analysis of man-machine interaction for control and display system in main control room of light water reactor

International Nuclear Information System (INIS)

Santosa, Kussigit; Supriatna, Piping; Karlina, Itjeu; Widagdo, Suharyo; Darlis; Sudiono, Bambang

1998-01-01

One of potential hazard in Nuclear Power Plant is the failure of its operation. The accident or operation failure in the reactor must be concerned event its probability is low. The important thing should be concerned is 'Analysis of Man-Machine Interaction (MMI) for Control and Display System in Main Control Room (MCR) of Nuclear Power Reactor', especially LWR type. Control and Display System in MCR of Reactor is the main part of MMI link process in Reactor MCR work system. Signal from display system showed performance process in reactor, while this signal will be received by operator. This signal will be described through central nerve for making decision what kind must be done. Then the operator manage the next process of reactor operation through control system. So by knowing Analysis of Man-Machine Interaction for Control and Display System in Main Control Room of Power Reactor, we can understand human error probability of the operator in reactor operation

Correlational approach to study interactions between dust Brownian particles in a plasma

Science.gov (United States)

Lisin, E. A.; Vaulina, O. S.; Petrov, O. F.

2018-01-01

A general approach to the correlational analysis of Brownian motion of strongly coupled particles in open dissipative systems is described. This approach can be applied to the theoretical description of various non-ideal statistically equilibrium systems (including non-Hamiltonian systems), as well as for the analysis of experimental data. In this paper, we consider an application of the correlational approach to the problem of experimental exploring the wake-mediated nonreciprocal interactions in complex plasmas. We derive simple analytic equations, which allows one to calculate the gradients of forces acting on a microparticle due to each of other particles as well as the gradients of external field, knowing only the information on time-averaged correlations of particles displacements and velocities. We show the importance of taking dissipative and random processes into account, without which consideration of a system with a nonreciprocal interparticle interaction as linearly coupled oscillators leads to significant errors in determining the characteristic frequencies in a system. In the examples of numerical simulations, we demonstrate that the proposed original approach could be an effective instrument in exploring the longitudinal wake structure of a microparticle in a plasma. Unlike the previous attempts to study the wake-mediated interactions in complex plasmas, our method does not require any external perturbations and is based on Brownian motion analysis only.

An Interactive Astronaut-Robot System with Gesture Control

Directory of Open Access Journals (Sweden)

Jinguo Liu

2016-01-01

Full Text Available Human-robot interaction (HRI plays an important role in future planetary exploration mission, where astronauts with extravehicular activities (EVA have to communicate with robot assistants by speech-type or gesture-type user interfaces embedded in their space suits. This paper presents an interactive astronaut-robot system integrating a data-glove with a space suit for the astronaut to use hand gestures to control a snake-like robot. Support vector machine (SVM is employed to recognize hand gestures and particle swarm optimization (PSO algorithm is used to optimize the parameters of SVM to further improve its recognition accuracy. Various hand gestures from American Sign Language (ASL have been selected and used to test and validate the performance of the proposed system.

Quality control methodology for high-throughput protein-protein interaction screening.

Science.gov (United States)

Vazquez, Alexei; Rual, Jean-François; Venkatesan, Kavitha

2011-01-01

Protein-protein interactions are key to many aspects of the cell, including its cytoskeletal structure, the signaling processes in which it is involved, or its metabolism. Failure to form protein complexes or signaling cascades may sometimes translate into pathologic conditions such as cancer or neurodegenerative diseases. The set of all protein interactions between the proteins encoded by an organism constitutes its protein interaction network, representing a scaffold for biological function. Knowing the protein interaction network of an organism, combined with other sources of biological information, can unravel fundamental biological circuits and may help better understand the molecular basics of human diseases. The protein interaction network of an organism can be mapped by combining data obtained from both low-throughput screens, i.e., "one gene at a time" experiments and high-throughput screens, i.e., screens designed to interrogate large sets of proteins at once. In either case, quality controls are required to deal with the inherent imperfect nature of experimental assays. In this chapter, we discuss experimental and statistical methodologies to quantify error rates in high-throughput protein-protein interactions screens.

Structural control of nonlinear optical absorption and refraction in dense metal nanoparticle arrays.

Science.gov (United States)

Kohlgraf-Owens, Dana C; Kik, Pieter G

2009-08-17

The linear and nonlinear optical properties of a composite containing interacting spherical silver nanoparticles embedded in a dielectric host are studied as a function of interparticle separation using three dimensional frequency domain simulations. It is shown that for a fixed amount of metal, the effective third-order nonlinear susceptibility of the composite chi((3))(omega) can be significantly enhanced with respect to the linear optical properties, due to a combination of resonant surface plasmon excitation and local field redistribution. It is shown that this geometry-dependent susceptibility enhancement can lead to an improved figure of merit for nonlinear absorption. Enhancement factors for the nonlinear susceptibility of the composite are calculated, and the complex nature of the enhancement factors is discussed.

Plasma Surface interaction in Controlled fusion devices

International Nuclear Information System (INIS)

1990-05-01

The subjects presented in the 9th conference on plasma surface interaction in controlled fusion devices were: the modifications of power scrape-off-length and power deposition during various configurations in Tore Supra plasmas; the effects observed in ergodic divertor experiments in Tore-Supra; the diffuse connexion induced by the ergodic divertor and the topology of the heat load patterns on the plasma facing components in Tore-Supra; the study of the influence of air exposure on graphite implanted by low energy high density deuterium plasma

Storing quantum information in XXZ spin rings with periodically time-controlled interactions

International Nuclear Information System (INIS)

Giampaolo, S M; Illuminati, F; Mazzarella, G

2005-01-01

We introduce a general scheme to realize massive quantum memories in simple systems of interacting qubits. Such systems are described by spin rings with XXZ intersite couplings of suitably time-periodically controlled amplitudes. We show that initially localized excitations undergo perfect periodic revivals, allowing for the simultaneous storage of arbitrary sets of different local states. This novel approach to the problem of storing quantum information hints at a new way to control and suppress the effect of decoherence on a quantum computer realized in a system with nonvanishing interactions between the constituent qubits

Storing quantum information in XXZ spin rings with periodically time-controlled interactions

Energy Technology Data Exchange (ETDEWEB)

Giampaolo, S M; Illuminati, F; Mazzarella, G [Dipartimento di Fisica ' E. R. Caianiello' , Universita di Salerno, INFM UdR di Salerno, INFN Sezione di Napoli, Gruppo Collegato di Salerno, Via S. Allende, 84081 Baronissi, SA (Italy)

2005-10-01

We introduce a general scheme to realize massive quantum memories in simple systems of interacting qubits. Such systems are described by spin rings with XXZ intersite couplings of suitably time-periodically controlled amplitudes. We show that initially localized excitations undergo perfect periodic revivals, allowing for the simultaneous storage of arbitrary sets of different local states. This novel approach to the problem of storing quantum information hints at a new way to control and suppress the effect of decoherence on a quantum computer realized in a system with nonvanishing interactions between the constituent qubits.

The Effects of Interactions between Management Control Systems and Strategy on Firm Performance: An Empirical Study

OpenAIRE

Melek Eker; Semih Eker

2016-01-01

In recent years, there has been growing interest in examining the relationships among management control systems, business strategy and firm performance. In this study, the interactions of management control systems and strategy with their impact on firm performance are examined with an empirical analysis, based on the data from 94 manufacturing firms from the top 500 in Turkey in 2014. The results support the postulate that high interaction between interactive control system (ICS) and differ...

Interaction between functional health literacy, patient activation, and glycemic control

Directory of Open Access Journals (Sweden)

Woodard LD

2014-07-01

Full Text Available LeChauncy D Woodard, Cassie R Landrum, Amber B Amspoker, David Ramsey, Aanand D Naik Veterans Affairs Health Services Research and Development Center for Innovations in Quality, Effectiveness and Safety, Michael E DeBakey Veterans Affairs Medical Center, and Section of Health Services Research, Department of Medicine, Baylor College of Medicine, Houston, TX, USA Background: Functional health literacy (FHL and patient activation can impact diabetes control through enhanced diabetes self-management. Less is known about the combined effect of these characteristics on diabetes outcomes. Using brief, validated measures, we examined the interaction between FHL and patient activation in predicting glycosylated hemoglobin (HbA1c control among a cohort of multimorbid diabetic patients.Methods: We administered a survey via mail to 387 diabetic patients with coexisting ­hypertension and ischemic heart disease who received outpatient care at one regional VA medical center between November 2010 and December 2010. We identified patients with the study conditions using the International Classification of Diseases-Ninth Revision-Clinical ­Modification (ICD-9-CM diagnoses codes and Current Procedure Terminology (CPT ­procedures codes. Surveys were returned by 195 (50.4% patients. We determined patient activation levels based on participant responses to the 13-item Patient Activation Measure and FHL levels using the single-item screening question, “How confident are you filling out medical forms by yourself?” We reviewed patient medical records to assess glycemic control. We used multiple logistic regression to examine whether activation and FHL were individually or jointly related to HbA1c control.Results: Neither patient activation nor FHL was independently related to glycemic control in the unadjusted main effects model; however, the interaction between the two was significantly associated with glycemic control (odds ratio 1.05 [95% confidence

Information Flow Analysis for Human-System Interaction in the SG Level Control

International Nuclear Information System (INIS)

Kim, Jong Hyun; Shin, Yeong Cheol

2008-01-01

Interaction between automatic control and operators is one of main issues in the application of automation technology. Inappropriate information from automatic control systems causes unexpected problems in human-automation collaboration. Poor information becomes critical, especially when the operator takes over the control from an automation system. Operators cannot properly handle the situation transferred from the automatic mode because of inadequate situation awareness, if the operator is out-of-the loop and the automatic control system fails. Some cases of unplanned reactor trips during the transition between the manual mode and the automatic mode are reported in nuclear power plants (NPPs). Among unplanned reactor trips since 2002, two cases were partially caused by automation-related failures of steam generator (SG) level control. This paper conducts information flow analysis to identify information and control requirement for human-system interaction of SG level control. At first, this paper identifies the level of automation in SG level control systems and then function allocation between system control and human operators. Then information flow analysis for monitoring and transition of automation is performed by adapting job process chart. Information and control requirements will be useful as an input for the human-system interface (HSI) design of SG level control

Spin reorientation in α-Fe2O3 nanoparticles induced by interparticle exchange interactions in alpha-Fe2O3/NiO nanocomposites

DEFF Research Database (Denmark)

Frandsen, Cathrine; Lefmann, Kim; Lebech, Bente

2011-01-01

We report that the spin structure of alpha-Fe2O3 nanoparticles rotates coherently out of the basal (001) plane at low temperatures when interacting with thin plate-shaped NiO nanoparticles. The observed spin reorientation (up to similar to 70 degrees) in alpha-Fe2O3 nanoparticles has, in appearan......, similarities to the Morin transition in bulk alpha-Fe2O3, but its origin is different-it is caused by exchange coupling between aggregated nanoparticles of alpha-Fe2O3 and NiO with different directions of easy axes of magnetization.......We report that the spin structure of alpha-Fe2O3 nanoparticles rotates coherently out of the basal (001) plane at low temperatures when interacting with thin plate-shaped NiO nanoparticles. The observed spin reorientation (up to similar to 70 degrees) in alpha-Fe2O3 nanoparticles has, in appearance...

Invariance of the Kohn center-of-mass mode in a conserving theory

NARCIS (Netherlands)

Bonitz, M.; Balzer, K.; van Leeuwen, R.

The center-of-mass (c.m.) oscillation of a many-body system in a harmonic trap is known to be independent of the interparticle interaction. However, this is not necessarily the case if the interactions are treated approximately. Here, we prove a simple general criterion for preservation of the c.m.

Dynamic Characterization and Interaction Control of the CBM-Motus Robot for Upper-Limb Rehabilitation

Directory of Open Access Journals (Sweden)

Loredana Zollo

2013-10-01

Full Text Available This paper presents dynamic characterization and control of an upper-limb rehabilitation machine aimed at improving robot performance in the interaction with the patient. An integrated approach between mechanics and control is the key issue of the paper for the development of a robotic machine with desirable dynamic properties. Robot inertial and acceleration properties are studied in the workspace via a graphical representation based on ellipses. Robot friction is experimentally retrieved by means of a parametric identification procedure. A current-based impedance control is developed in order to compensate for friction and enhance control performance in the interaction with the patient by means of force feedback, without increasing system inertia. To this end, servo-amplifier motor currents are monitored to provide force feedback in the interaction, thus avoiding the need for force sensors mounted at the robot end-effector. Current-based impedance control is implemented on the robot; experimental results in free space as well as in constrained space are provided.

Alternating magnetic field energy absorption in the dispersion of iron oxide nanoparticles in a viscous medium

Energy Technology Data Exchange (ETDEWEB)

Smolkova, Ilona S. [Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, nad Ovcirnou 3685, 760 01 Zlin (Czech Republic); Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, T.G. Masaryk Sq. 275, 762 72 Zlin (Czech Republic); Kazantseva, Natalia E., E-mail: nekazan@yahoo.com [Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, nad Ovcirnou 3685, 760 01 Zlin (Czech Republic); Babayan, Vladimir; Smolka, Petr; Parmar, Harshida; Vilcakova, Jarmila [Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, nad Ovcirnou 3685, 760 01 Zlin (Czech Republic); Schneeweiss, Oldrich; Pizurova, Nadezda [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic)

2015-01-15

Magnetic iron oxide nanoparticles were obtained by a coprecipitation method in a controlled growth process leading to the formation of uniform highly crystalline nanoparticles with average size of 13 nm, which corresponds to the superparamagnetic state. Nanoparticles obtained are a mixture of single-phase nanoparticles of magnetite and maghemite as well as nanoparticles of non-stoichiometric magnetite. The subsequent annealing of nanoparticles at 300 °C in air during 6 h leads to the full transformation to maghemite. It results in reduced value of the saturation magnetization (from 56 emu g{sup −1} to 48 emu g{sup −1}) but does not affect the heating ability of nanoparticles. A 2–7 wt% dispersion of as-prepared and annealed nanoparticles in glycerol provides high heating rate in alternating magnetic fields allowed for application in magnetic hyperthermia; however the value of specific loss power does not exceed 30 W g{sup −1}. This feature of heat output is explained by the combined effect of magnetic interparticle interactions and the properties of the carrier medium. Nanoparticles coalesce during the synthesis and form aggregates showing ferromagnetic-like behavior with magnetization hysteresis, distinct sextets on Mössbauer spectrum, blocking temperature well about room temperature, which accounts for the higher energy barrier for magnetization reversal. At the same time, low specific heat capacity of glycerol intensifies heat transfer in the magnetic dispersion. However, high viscosity of glycerol limits the specific loss power value, since predominantly the Neel relaxation accounts for the absorption of AC magnetic field energy. - Highlights: • Mixed phase iron oxide magnetic nanoparticles were obtained by coprecipitation. • A part of nanoparticles was annealed at 300 °C to achieve the single-phase γ-Fe{sub 2}O{sub 3}. • Nanoparticles revealed ferromagnetic-like behavior due to interparticle interactions. • Nanoparticles glycerol

Water-Based Assembly and Purification of Plasmon-Coupled Gold Nanoparticle Dimers and Trimers

Directory of Open Access Journals (Sweden)

Sébastien Bidault

2012-01-01

Full Text Available We describe a simple one-pot water-based scheme to produce gold nanoparticle groupings with short interparticle spacings. This approach combines a cross-linking molecule and a hydrophilic passivation layer to control the level of induced aggregation. Suspensions of dimers and trimers are readily obtained using a single electrophoretic purification step. The final interparticle spacings allow efficient coupling of the particle plasmon modes as verified in extinction spectroscopy.

Design considerations for CdTe Nanotetrapods as electronic devices. krogstrup@fys.ku.dk.

Science.gov (United States)

Teich-McGoldrick, S L; Bellanger, M; Caussanel, M; Tsetseris, L; Pantelides, S T; Glotzer, S C; Schrimpf, R D

2009-11-01

We investigate the feasibility of using CdTe nanotetrapods as circuit elements using models and simulation at multiple scales. Technology computer-aided design tools are used to simulate the electrical behavior for both metal-semiconductor field-effect transistors and junction field-effect transistors. Our results show that by varying the doping concentrations and material composition, CdTe nanotetrapods have the potential to be useful circuit elements. Monte Carlo simulations provide insight into how control over interparticle and particle-substrate interactions can lead to the directed assembly of ordered arrays of electrically gated nanotetrapods.

Modelling control of epidemics spreading by long-range interactions.

Science.gov (United States)

Dybiec, Bartłomiej; Kleczkowski, Adam; Gilligan, Christopher A

2009-10-06

We have studied the spread of epidemics characterized by a mixture of local and non-local interactions. The infection spreads on a two-dimensional lattice with the fixed nearest neighbour connections. In addition, long-range dynamical links are formed by moving agents (vectors). Vectors perform random walks, with step length distributed according to a thick-tail distribution. Two distributions are considered in this paper, an alpha-stable distribution describing self-similar vector movement, yet characterized by an infinite variance and an exponential power characterized by a large but finite variance. Such long-range interactions are hard to track and make control of epidemics very difficult. We also allowed for cryptic infection, whereby an infected individual on the lattice can be infectious prior to showing any symptoms of infection or disease. To account for such cryptic spread, we considered a control strategy in which not only detected, i.e. symptomatic, individuals but also all individuals within a certain control neighbourhood are treated upon the detection of disease. We show that it is possible to eradicate the disease by using such purely local control measures, even in the presence of long-range jumps. In particular, we show that the success of local control and the choice of the optimal strategy depend in a non-trivial way on the dispersal patterns of the vectors. By characterizing these patterns using the stability index of the alpha-stable distribution to change the power-law behaviour or the exponent characterizing the decay of an exponential power distribution, we show that infection can be successfully contained using relatively small control neighbourhoods for two limiting cases for long-distance dispersal and for vectors that are much more limited in their dispersal range.

Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

Energy Technology Data Exchange (ETDEWEB)

Gon Corradini, Patricia; Pires, Felipe I.; Paganin, Valdecir A.; Perez, Joelma, E-mail: jperez@iqsc.usp.br [Instituto de Quimica de Sao Carlos, USP (Brazil); Antolini, Ermete [Scuola di Scienza dei Materiali (Italy)

2012-09-15

The effect of the relationship between particle size (d), inter-particle distance (x{sub i}), and metal loading (y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5-3 nm) and x{sub i}/d (>5) values, was evaluated. It was found that for y < 30 wt%, the optimum values of both d and x{sub i}/d can be always obtained. For y {>=} 30 wt%, instead, the positive effect of a thinner catalyst layer of the fuel cell electrode than that using catalysts with y < 30 wt% is concomitant to a decrease of the effective catalyst surface area due to an increase of d and/or a decrease of x{sub i}/d compared to their optimum values, with in turns gives rise to a decrease in the catalytic activity. The effect of the x{sub i}/d ratio has been successfully verified by experimental results on ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x{sub i}/d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.

Control rod interaction models for use in 2D and 3D reactor geometries

International Nuclear Information System (INIS)

Bannerman, R.C.

1985-11-01

Control rod interaction models are developed for use in two-dimensional and three-dimensional reactor geometries. These models allow the total worth of any combination of control rods inserted to be determined from the individual worths in conjunction with an algorithm representing interaction effects between them. The validity of the assumptions is demonstrated for fast and thermal systems showing modelling errors of 1#percent# or less in inserted control rod worths. The models are ideally suited for most reactor systems. (UK)

Interactive Control System, Intended Strategy, Implemented Strategy dan Emergent Strategy

OpenAIRE

Tubagus Ismail; Darjat Sudrajat

2012-01-01

The purpose of this study was to examine the relationship between management control system (MCS) and strategy formation processes, namely: intended strategy, emergent strategy and impelemented strategy. The focus of MCS in this study was interactive control system. The study was based on Structural Equation Modeling (SEM) as its multivariate analyses instrument. The samples were upper middle managers of manufacturing company in Banten Province, DKI Jakarta Province and West Java Province. AM...

Examining relations between locus of control, loneliness, subjective well-being, and preference for online social interaction.

Science.gov (United States)

Ye, Yinghua; Lin, Lin

2015-02-01

The unprecedented popularity of online communication has raised interests and concerns among the public as well as in scholarly circles. Online communications have pushed people farther away from one another. This study is a further examination of the effects of online communications on well-being, in particular: Locus of control, Loneliness, Subjective well-being, and Preference for online social interaction. Chinese undergraduate students (N = 260; 84 men, 176 women; M age = 20.1 yr., SD = 1.2) were questioned about demographic information and use of social media as well as four previously validated questionnaires related to well-being. Most participants used QQ, a popular social networking program, as the major channel for online social interactions. Locus of control was positively related to Loneliness and Preference for online social interaction, but negatively related to Subjective well-being; Loneliness (positively) and Subjective well-being (negatively) were related to Preference for online social interaction; and Loneliness and Subjective well-being had a full mediating effect between the relationships of Locus of control and Preference for online social interaction. The findings of the study showed that more lonely, unhappy, and externally controlled students were more likely to be engaged in online social interaction. Improving students' locus of control, loneliness, and happiness may help reduce problematic Internet use.

BTG interacts with retinoblastoma to control cell fate in Dictyostelium.

Directory of Open Access Journals (Sweden)

Daniele Conte

Full Text Available BACKGROUND: In the genesis of many tissues, a phase of cell proliferation is followed by cell cycle exit and terminal differentiation. The latter two processes overlap: genes involved in the cessation of growth may also be important in triggering differentiation. Though conceptually distinct, they are often causally related and functional interactions between the cell cycle machinery and cell fate control networks are fundamental to coordinate growth and differentiation. A switch from proliferation to differentiation may also be important in the life cycle of single-celled organisms, and genes which arose as regulators of microbial differentiation may be conserved in higher organisms. Studies in microorganisms may thus contribute to understanding the molecular links between cell cycle machinery and the determination of cell fate choice networks. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that in the amoebozoan D. discoideum, an ortholog of the metazoan antiproliferative gene btg controls cell fate, and that this function is dependent on the presence of a second tumor suppressor ortholog, the retinoblastoma-like gene product. Specifically, we find that btg-overexpressing cells preferentially adopt a stalk cell (and, more particularly, an Anterior-Like Cell fate. No btg-dependent preference for ALC fate is observed in cells in which the retinoblastoma-like gene has been genetically inactivated. Dictyostelium btg is the only example of non-metazoan member of the BTG family characterized so far, suggesting that a genetic interaction between btg and Rb predated the divergence between dictyostelids and metazoa. CONCLUSIONS/SIGNIFICANCE: While the requirement for retinoblastoma function for BTG antiproliferative activity in metazoans is known, an interaction of these genes in the control of cell fate has not been previously documented. Involvement of a single pathway in the control of mutually exclusive processes may have relevant implication in the

Graphene as a flexible template for controlling magnetic interactions between metal atoms.

Science.gov (United States)

Lee, Sungwoo; Kim, Dongwook; Robertson, Alex W; Yoon, Euijoon; Hong, Suklyun; Ihm, Jisoon; Yu, Jaejun; Warner, Jamie H; Lee, Gun-Do

2017-03-01

Metal-doped graphene produces magnetic moments that have potential application in spintronics. Here we use density function theory computational methods to show how the magnetic interaction between metal atoms doped in graphene can be controlled by the degree of flexure in a graphene membrane. Bending graphene by flexing causes the distance between two substitutional Fe atoms covalently bonded in graphene to gradually increase and these results in the magnetic moment disappearing at a critical strain value. At the critical strain, a carbon atom can enter between the two Fe atoms and blocks the interaction between relevant orbitals of Fe atoms to quench the magnetic moment. The control of interactions between doped atoms by exploiting the mechanical flexibility of graphene is a unique approach to manipulating the magnetic properties and opens up new opportunities for mechanical-magnetic 2D device systems.

Dynamic magnetoconductance fluctuations and oscillations in mesoscopic wires and rings

DEFF Research Database (Denmark)

Liu, D. Z.; Hu, Ben Yu-Kuang; Stafford, C. A.

1994-01-01

Using a finite-frequency recursive Green's-function technique, we calculate the dynamic magnetoconductance fluctuations and oscillations in disordered mesoscopic normal-metal systems, incorporating interparticle Coulomb interactions within a self-consistent potential method. In a disorderd metal ...

Computer tomography guided lung biopsy using interactive breath-hold control

DEFF Research Database (Denmark)

Ashraf, Haseem; Krag-Andersen, Shella; Naqibullah, Matiullah

2017-01-01

Background: Interactive breath-hold control (IBC) may improve the accuracy and decrease the complication rate of computed tomography (CT)-guided lung biopsy, but this presumption has not been proven in a randomized study. Methods: Patients admitted for CT-guided lung biopsy were randomized...

Effects of Pilates exercises on sensory interaction, postural control and fatigue in patients with multiple sclerosis.

Science.gov (United States)

Soysal Tomruk, Melda; Uz, Muhammed Zahid; Kara, Bilge; İdiman, Egemen

2016-05-01

Decreased postural control, sensory integration deficits and fatigue are important problems that cause functional impairments in patients with multiple sclerosis (pwMS). To examine the effect of modified clinical Pilates exercises on sensory interaction and balance, postural control and fatigue in pwMS. Eleven patients with multiple sclerosis and 12 healthy matched controls were recruited in this study. Limits of stability and postural stability tests were used to evaluate postural control by Biodex Balance System and sensory interaction assessed. Fatigue was assessed by Modified Fatigue Impact Scale. Pilates exercises were applied two times a week for 10 weeks and measurements were repeated to pwMS after exercise training. Postural control and fatigue (except psychosocial parameter) of pwMS were significantly worser than healthy controls (pPilates training (ppilates exercises (p>0.05). Ten-week Pilates training is effective to improve sensory interaction and to decrease fatigue. Pilates exercises can be applied safely in ambulatory pwMS for enhance sensory interaction and balance and combat fatigue. More investigations are needed. Copyright © 2016 Elsevier B.V. All rights reserved.

Identifying Ant-Mirid Spatial Interactions to Improve Biological Control in Cacao-Based Agroforestry System.

Science.gov (United States)

Bagny Beilhe, Leïla; Piou, Cyril; Tadu, Zéphirin; Babin, Régis

2018-06-06

The use of ants for biological control of insect pests was the first reported case of conservation biological control. Direct and indirect community interactions between ants and pests lead to differential spatial pattern. We investigated spatial interactions between mirids, the major cocoa pest in West Africa and numerically dominant ant species, using bivariate point pattern analysis to identify potential biological control agents. We assume that potential biological control agents should display negative spatial interactions with mirids considering their niche overlap. The mirid/ant data were collected in complex cacao-based agroforestry systems sampled in three agroecological areas over a forest-savannah gradient in Cameroon. Three species, Crematogaster striatula Emery (Hymenoptera: Formicidae), Crematogaster clariventris Mayr (Hymenoptera: Formicidae), and Oecophylla longinoda Latreille (Hymenoptera: Formicidae) with high predator and aggressive behaviors were identified as dominant and showed negative spatial relationships with mirids. The weaver ant, O. longinoda was identified as the only potential biological control agent, considering its ubiquity in the plots, the similarity in niche requirements, and the spatial segregation with mirids resulting probably from exclusion mechanisms. Combining bivariate point pattern analysis to good knowledge of insect ecology was an effective method to identify a potentially good biological control agent.

Preparation and characterization of physically modified glass beads used as model carriers in dry powder inhalers.

Science.gov (United States)

Zellnitz, Sarah; Redlinger-Pohn, Jakob Dominik; Kappl, Michael; Schroettner, Hartmuth; Urbanetz, Nora Anne

2013-04-15

The aim of this work is the physical modification and characterization of the surface topography of glass beads used as model carriers in dry powder inhalers (DPIs). By surface modification the contact area between drug and carrier and thereby interparticle forces may be modified. Thus the performance of DPIs that relies on interparticle interactions may be improved. Glass beads were chosen as model carriers because various prospects of physical surface modification may be applied without affecting other factors also impacting interparticle interactions like particle size and shape. To generate rough surfaces glass beads were processed mechanically by friction and impaction in a ball mill with different grinding materials that were smaller and harder with respect to the glass beads. By varying the grinding time (4 h, 8 h) and by using different grinding media (tungsten carbide, quartz) surfaces with different shades of roughness were generated. Depending on the hardness of the grinding material and the grinding time the surface roughness was more or less pronounced. Surface roughness parameters and specific surface area were determined via several complementary techniques in order to get an enhanced understanding of the impact of the modifying procedure on the surface properties of the glass beads. Copyright © 2013 Elsevier B.V. All rights reserved.

On the ground state for fractional quantum hall effect

International Nuclear Information System (INIS)

Jellal, A.

1998-09-01

In the present letter, we investigate the ground state wave function for an explicit model of electrons in an external magnetic field with specific inter-particle interactions. The excitation states of this model are also given. (author)

Pair interactions in polyelectrolyte-nanoparticle systems: Influence of dielectric inhomogeneities and the partial dissociation of polymers and nanoparticles

International Nuclear Information System (INIS)

Pryamitsyn, Victor; Ganesan, Venkat

2015-01-01

We study the effective pair interactions between two charged spherical particles in polyelectrolyte solutions using polymer self-consistent field theory. In a recent study [V. Pryamitsyn and V. Ganesan, Macromolecules 47, 6095 (2015)], we considered a model in which the particles possess fixed charge density, the polymers contain a prespecified amount of dissociated charges and, the dielectric constant of the solution was assumed to be homogeneous in space and independent of the polymer concentration. In this article, we present results extending our earlier model to study situations in which either or both the particle and the polymers possess partially dissociable groups. Additionally, we also consider the case when the dielectric constant of the solution depends on the local concentration of the polymers and when the particle’s dielectric constant is lower than that of the solvent. For each case, we quantify the polymer-mediated interactions between the particles as a function of the polymer concentrations and the degree of dissociation of the polymer and particles. Consistent with the results of our previous study, we observe that the polymer-mediated interparticle interactions consist of a short-range attraction and a long-range repulsion. The partial dissociablity of the polymer and particles was seen to have a strong influence on the strength of the repulsive portion of the interactions. Rendering the dielectric permittivity to be inhomogeneous has an even stronger effect on the repulsive interactions and results in changes to the qualitative nature of interactions in some parametric ranges

Parametric analysis of the thermodynamic properties for a medium with strong interaction between particles

International Nuclear Information System (INIS)

Dubovitskii, V.A.; Pavlov, G.A.; Krasnikov, Yu.G.

1996-01-01

Thermodynamic analysis of media with strong interparticle (Coulomb) interaction is presented. A method for constructing isotherms is proposed for a medium described by a closed multicomponent thermodynamic model. The method is based on choosing an appropriate nondegenerate frame of reference in the extended space of thermodynamic variables and provides efficient thermodynamic calculations in a wide range of parameters, for an investigation of phase transitions of the first kind, and for determining both the number of phases and coexistence curves. A number of approximate thermodynamic models of hydrogen plasma are discussed. The approximation corresponding to the n5/2 law, in which the effects of particle attraction and repulsion are taken into account qualitatively, is studied. This approximation allows studies of thermodynamic properties of a substance for a wide range of parameters. In this approximation, for hydrogen at a constant temperature, various properties of the degree of ionization are revealed. In addition, the parameters of the second critical point are found under conditions corresponding to the Jovian interior

Eye Tracking Based Control System for Natural Human-Computer Interaction

Directory of Open Access Journals (Sweden)

Xuebai Zhang

2017-01-01

Full Text Available Eye movement can be regarded as a pivotal real-time input medium for human-computer communication, which is especially important for people with physical disability. In order to improve the reliability, mobility, and usability of eye tracking technique in user-computer dialogue, a novel eye control system with integrating both mouse and keyboard functions is proposed in this paper. The proposed system focuses on providing a simple and convenient interactive mode by only using user’s eye. The usage flow of the proposed system is designed to perfectly follow human natural habits. Additionally, a magnifier module is proposed to allow the accurate operation. In the experiment, two interactive tasks with different difficulty (searching article and browsing multimedia web were done to compare the proposed eye control tool with an existing system. The Technology Acceptance Model (TAM measures are used to evaluate the perceived effectiveness of our system. It is demonstrated that the proposed system is very effective with regard to usability and interface design.

Eye Tracking Based Control System for Natural Human-Computer Interaction.

Science.gov (United States)

Zhang, Xuebai; Liu, Xiaolong; Yuan, Shyan-Ming; Lin, Shu-Fan

2017-01-01

Eye movement can be regarded as a pivotal real-time input medium for human-computer communication, which is especially important for people with physical disability. In order to improve the reliability, mobility, and usability of eye tracking technique in user-computer dialogue, a novel eye control system with integrating both mouse and keyboard functions is proposed in this paper. The proposed system focuses on providing a simple and convenient interactive mode by only using user's eye. The usage flow of the proposed system is designed to perfectly follow human natural habits. Additionally, a magnifier module is proposed to allow the accurate operation. In the experiment, two interactive tasks with different difficulty (searching article and browsing multimedia web) were done to compare the proposed eye control tool with an existing system. The Technology Acceptance Model (TAM) measures are used to evaluate the perceived effectiveness of our system. It is demonstrated that the proposed system is very effective with regard to usability and interface design.

Many-particle interference beyond many-boson and many-fermion statistics

DEFF Research Database (Denmark)

Tichy, Malte C.; Tiersch, Markus; Mintert, Florian

2012-01-01

Identical particles exhibit correlations even in the absence of inter-particle interaction, due to the exchange (anti)symmetry of the many-particle wavefunction. Two fermions obey the Pauli principle and anti-bunch, whereas two bosons favor bunched, doubly occupied states. Here, we show that the ......Identical particles exhibit correlations even in the absence of inter-particle interaction, due to the exchange (anti)symmetry of the many-particle wavefunction. Two fermions obey the Pauli principle and anti-bunch, whereas two bosons favor bunched, doubly occupied states. Here, we show...... that the collective interference of three or more particles leads to much more diverse behavior than expected from the boson–fermion dichotomy known from quantum statistical mechanics. The emerging complexity of many-particle interference is tamed by a simple law for the strict suppression of events in the Bell...

Quantitatively Probing the Means of Controlling Nanoparticle Assembly on Surfaces

Energy Technology Data Exchange (ETDEWEB)

Patete, J.m.; Wong, S.; Peng, X.; Serafin, J.M.

2011-05-17

As a means of developing a simple, cost-effective, and reliable method for probing nanoparticle behavior, we have used atomic force microscopy to gain a quantitative 3D visual representation of the deposition patterns of citrate-capped Au nanoparticles on a substrate as a function of (a) sample preparation, (b) the choice of substrate, (c) the dispersion solvent, and (d) the number of loading steps. Specifically, we have found that all four parameters can be independently controlled and manipulated in order to alter the resulting pattern and quantity of as-deposited nanoparticles. From these data, the sample preparation technique appears to influence deposition patterns most broadly, and the dispersion solvent is the most convenient parameter to use in tuning the quantity of nanoparticles deposited onto the surface under spin-coating conditions. Indeed, we have quantitatively measured the effect of surface coverage for both mica and silicon substrates under preparation techniques associated with (i) evaporation under ambient air, (ii) heat treatment, and (iii) spin-coating preparation conditions. In addition, we have observed a decrease in nanoparticle adhesion to a substrate when the ethylene glycol content of the colloidal dispersion solvent is increased, which had the effect of decreasing interparticle-substrate interactions. Finally, we have shown that substrates prepared by these diverse techniques have potential applicability in surface-enhanced Raman spectroscopy.

Quantitatively Probing the Means of Controlling Nanoparticle Assembly on Surfaces

International Nuclear Information System (INIS)

Patete, J.M.; Wong, S.; Peng, X.; Serafin, J.M.

2011-01-01

As a means of developing a simple, cost-effective, and reliable method for probing nanoparticle behavior, we have used atomic force microscopy to gain a quantitative 3D visual representation of the deposition patterns of citrate-capped Au nanoparticles on a substrate as a function of (a) sample preparation, (b) the choice of substrate, (c) the dispersion solvent, and (d) the number of loading steps. Specifically, we have found that all four parameters can be independently controlled and manipulated in order to alter the resulting pattern and quantity of as-deposited nanoparticles. From these data, the sample preparation technique appears to influence deposition patterns most broadly, and the dispersion solvent is the most convenient parameter to use in tuning the quantity of nanoparticles deposited onto the surface under spin-coating conditions. Indeed, we have quantitatively measured the effect of surface coverage for both mica and silicon substrates under preparation techniques associated with (i) evaporation under ambient air, (ii) heat treatment, and (iii) spin-coating preparation conditions. In addition, we have observed a decrease in nanoparticle adhesion to a substrate when the ethylene glycol content of the colloidal dispersion solvent is increased, which had the effect of decreasing interparticle-substrate interactions. Finally, we have shown that substrates prepared by these diverse techniques have potential applicability in surface-enhanced Raman spectroscopy.

Effectiveness of Interactive Self-Management Interventions in Individuals With Poorly Controlled Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials.

Science.gov (United States)

Cheng, Li; Sit, Janet W H; Choi, Kai-Chow; Chair, Sek-Ying; Li, Xiaomei; He, Xiao-le

2017-02-01

To identify, assess, and summarize available scientific evidence on the effectiveness of interactive self-management interventions on glycemic control and patient-centered outcomes in individuals with poorly controlled type 2 diabetes. Major English and Chinese electronic databases including Medline, EMBASE, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, and WanFang Data were searched to identify randomized controlled trials that reported the effectiveness of interactive self-management interventions in individuals with poorly controlled type 2 diabetes (glycated hemoglobin [HbA1c] ≥ 7.5% or 58 mmol/mol), from inception to June 2015. Data extraction and risk-of-bias assessment were performed by two reviewers independently. Meta-analysis was performed using Review Manager 5.3. A total of 16 trials with 3,545 participants were included in the meta-analysis. Interactive self-management interventions could have a beneficial effect in individuals with poorly controlled type 2 diabetes in reducing HbA1c (mean difference: -0.43%, 95% CI: -0.67% to -0.18%), improving diabetes knowledge (standardized mean difference [SMD]: 0.30, 95% CI: 0.03 to 0.58), enhancing self-efficacy (SMD: 0.29, 95% CI: 0.14 to 0.44), and reducing diabetes-related distress (SMD: -0.21, 95% CI: -0.39 to -0.04). Self-management interventions supported with theory and structured curriculum showed desirable results in glycemic control. The behavioral change techniques, including providing feedback on performance, problem-solving, and action planning, were associated with a significant reduction in HbA1c. Individuals with poorly controlled type 2 diabetes could benefit from interactive self-management interventions. Interventions targeting patients with poorly controlled diabetes, those who are at the greatest risk of developing complications, should be prioritized. Our findings indicate that providing feedback on performance, problem-solving, and action

Functional, interactive and critical health literacy: Varying relationships with control over care and number of GP visits.

Science.gov (United States)

van der Heide, Iris; Heijmans, Monique; Schuit, A Jantine; Uiters, Ellen; Rademakers, Jany

2015-08-01

The aim of this study is to examine the extent to which functional, interactive and critical health literacy are associated with patients' perceived control over care and frequency of GP visits. Data from the Dutch 'National Panel of People with Chronic Illness or Disability' was used (N=2508). Health literacy was assessed by the Functional, Communicative and Critical Health Literacy measure. Perceived control over care was indicated by perceived ability to organize care, interact with providers and to perform self-care. By multivariate linear and logistic regression analyses, associations between health literacy and perceived control over care and subsequently frequency of GP visits were studied. Mainly interactive health literacy was associated with patients' perceived ability to organize care, interact with healthcare providers and perform self-care, whereas only functional health literacy was associated with number of GP visits. The results imply that some patients' may be less able to exert control over their care because of lower health literacy. Functional, interactive and critical health literacy vary in their relevance for patients' ability to exert control. Initiatives for strengthening patients' role in healthcare may be improved by paying attention to patients' health literacy, specifically functional and interactive health literacy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Plasmonic hybrid nanostructure with controlled interaction strength

Science.gov (United States)

Grzelak, Justyna K.; Krajnik, Bartosz; Thoreson, Mark D.; Nyga, Piotr; Shalaev, Vladimir M.; Mackowski, Sebastian

2014-03-01

In this report we discuss the influence of plasmon excitations in a silver island film on the fluorescence of photosynthetic complex, peridinin-chlorophyll-protein (PCP). Control of the separation between these two components is obtained by fabricating a wedge layer of silica across the substrate, with a thickness from 0 to 46 nm. Continuous variation of the silica thickness allows for gradual change of interaction strength between plasmon excitations in the metallic film and the excited states of pigments comprising photosynthetic complexes. While the largest separation between the silver film and photosynthetic complexes results in fluorescence featuring a mono-exponential decay and relatively narrow distribution of intensities, the PCP complexes placed on thinner silica spacers show biexponential fluorescence decay and significantly broader distribution of total fluorescence intensities. This broad distribution is a signature of stronger sensitivity of fluorescence enhancement upon actual parameters of a hybrid nanostructure. By gradual change of the silica spacer thickness we are able to reproduce classical distance dependence of fluorescence intensity in plasmonic hybrid nanostructures on ensemble level. Experiments carried out for different excitation wavelengths indicate that the interaction is stronger for excitations resonant with plasmon absorption in the metallic layer.

When ecosystem services interact: crop pollination benefits depend on the level of pest control

Science.gov (United States)

Lundin, Ola; Smith, Henrik G.; Rundlöf, Maj; Bommarco, Riccardo

2013-01-01

Pollination is a key ecosystem service which most often has been studied in isolation although effects of pollination on seed set might depend on, and interact with, other services important for crop production. We tested three competing hypotheses on how insect pollination and pest control might jointly affect seed set: independent, compensatory or synergistic effects. For this, we performed a cage experiment with two levels of insect pollination and simulated pest control in red clover (Trifolium pratense L.) grown for seed. There was a synergistic interaction between the two services: the gain in seed set obtained when simultaneously increasing pollination and pest control outweighed the sum of seed set gains obtained when increasing each service separately. This study shows that interactions can alter the benefits obtained from service-providing organisms, and this needs to be considered to properly manage multiple ecosystem services. PMID:23269852

The magnetic moment of NiO nanoparticles determined by Mössbauer spectroscopy

DEFF Research Database (Denmark)

Bahl, Christian Robert Haffenden; Hansen, Mikkel Fougt; Pedersen, Thomas

2006-01-01

We have studied the magnetic properties of 57Fe-doped NiO nanoparticles using Mössbauer spectroscopy and magnetization measurements. Two samples with different degrees of interparticle interaction were studied. In both samples the particles were characterized by high-resolution transmission...

Interactions Between Indirect DC-Voltage Estimation and Circulating Current Controllers of MMC-Based HVDC Transmission Systems

DEFF Research Database (Denmark)

Wickramasinghe, Harith R.; Konstantinou, Georgios; Pou, Josep

2018-01-01

Estimation-based indirect dc-voltage control in MMCs interacts with circulating current control methods. This paper proposes an estimation-based indirect dc-voltage control method for MMC-HVDC systems and analyzes its performance compared to alternative estimations. The interactions between......-state and transient performance is demonstrated using a benchmark MMC-HVDC transmission system, implemented in a real-time digital simulator. The results verify the theoretical evaluations and illustrate the operation and performance of the proposed indirect dc-voltage control method....

Parallel Vortex Body Interaction Enabled by Active Flow Control

Science.gov (United States)

Weingaertner, Andre; Tewes, Philipp; Little, Jesse

2017-11-01

An experimental study was conducted to explore the flow physics of parallel vortex body interaction between two NACA 0012 airfoils. Experiments were carried out at chord Reynolds numbers of 740,000. Initially, the leading airfoil was characterized without the target one being installed. Results are in good agreement with thin airfoil theory and data provided in the literature. Afterward, the leading airfoil was fixed at 18° incidence and the target airfoil was installed 6 chord lengths downstream. Plasma actuation (ns-DBD), originating close to the leading edge, was used to control vortex shedding from the leading airfoil at various frequencies (0.04 governing parameters of this vortex body interaction are explored. This work was supported by the Army Research Office under ARO Grant No. W911NF-14-1-0662.

Engineering systems for the generation of patterned co-cultures for controlling cell-cell interactions.

Science.gov (United States)

Kaji, Hirokazu; Camci-Unal, Gulden; Langer, Robert; Khademhosseini, Ali

2011-03-01

Inside the body, cells lie in direct contact or in close proximity to other cell types in a tightly controlled architecture that often regulates the resulting tissue function. Therefore, tissue engineering constructs that aim to reproduce the architecture and the geometry of tissues will benefit from methods of controlling cell-cell interactions with microscale resolution. We discuss the use of microfabrication technologies for generating patterned co-cultures. In addition, we categorize patterned co-culture systems by cell type and discuss the implications of regulating cell-cell interactions in the resulting biological function of the tissues. Patterned co-cultures are a useful tool for fabricating tissue engineered constructs and for studying cell-cell interactions in vitro, because they can be used to control the degree of homotypic and heterotypic cell-cell contact. In addition, this approach can be manipulated to elucidate important factors involved in cell-matrix interactions. Patterned co-culture strategies hold significant potential to develop biomimetic structures for tissue engineering. It is expected that they would create opportunities to develop artificial tissues in the future. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine. 2010 Elsevier B.V. All rights reserved.

Internal/external locus of control, self-esteem, and parental verbal interaction of at-risk black male adolescents.

Science.gov (United States)

Enger, J M; Howerton, D L; Cobbs, C R

1994-06-01

We investigated the relationship between three factors--internal/external locus of control, self-esteem, and parental verbal interaction--for at-risk Black male adolescents in the United States. Forty-two male students in Grades 6, 7, and 8 who had been identified by their teachers as being at risk completed the Locus of Control Scale for Children (Nowicki & Strickland, 1973), the Self-Esteem Inventory (Coopersmith, 1967), and the Verbal Interaction Questionnaire (Blake, 1991). A moderate positive relationship found between self-esteem and parental verbal interaction was consistent with a previous finding for White high school students. A moderate negative relationship found between locus of control and self-esteem differed from a previous finding of no significant relationship for Black elementary children. A weak, yet significant, negative relationship was found between locus of control and parental verbal interaction.

Robust Tests for Additive Gene-Environment Interaction in Case-Control Studies Using Gene-Environment Independence

DEFF Research Database (Denmark)

Liu, Gang; Lee, Seunggeun; Lee, Alice W

2018-01-01

test with case-control data. Our simulation studies suggest that the EB approach uses the gene-environment independence assumption in a data-adaptive way and provides power gain compared to the standard logistic regression analysis and better control of Type I error when compared to the analysis......There have been recent proposals advocating the use of additive gene-environment interaction instead of the widely used multiplicative scale, as a more relevant public health measure. Using gene-environment independence enhances the power for testing multiplicative interaction in case......-control studies. However, under departure from this assumption, substantial bias in the estimates and inflated Type I error in the corresponding tests can occur. This paper extends the empirical Bayes (EB) approach previously developed for multiplicative interaction that trades off between bias and efficiency...

Pigeon interaction mode switch-based UAV distributed flocking control under obstacle environments.

Science.gov (United States)

Qiu, Huaxin; Duan, Haibin

2017-11-01

Unmanned aerial vehicle (UAV) flocking control is a serious and challenging problem due to local interactions and changing environments. In this paper, a pigeon flocking model and a pigeon coordinated obstacle-avoiding model are proposed based on a behavior that pigeon flocks will switch between hierarchical and egalitarian interaction mode at different flight phases. Owning to the similarity between bird flocks and UAV swarms in essence, a distributed flocking control algorithm based on the proposed pigeon flocking and coordinated obstacle-avoiding models is designed to coordinate a heterogeneous UAV swarm to fly though obstacle environments with few informed individuals. The comparative simulation results are elaborated to show the feasibility, validity and superiority of our proposed algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Filtration of engineered nanoparticles using porous membranes

NARCIS (Netherlands)

Trzaskus, Krzystof

2016-01-01

The research presented in this thesis aims at providing a better understanding of the fundamental aspects responsible for nanoparticle removal and fouling development during filtration of engineered nanoparticles. The emphasis is put on the role of interparticle interactions in the feed solution,

A Radiation Chemistry Code Based on the Greens Functions of the Diffusion Equation

Science.gov (United States)

Plante, Ianik; Wu, Honglu

2014-01-01

Ionizing radiation produces several radiolytic species such as.OH, e-aq, and H. when interacting with biological matter. Following their creation, radiolytic species diffuse and chemically react with biological molecules such as DNA. Despite years of research, many questions on the DNA damage by ionizing radiation remains, notably on the indirect effect, i.e. the damage resulting from the reactions of the radiolytic species with DNA. To simulate DNA damage by ionizing radiation, we are developing a step-by-step radiation chemistry code that is based on the Green's functions of the diffusion equation (GFDE), which is able to follow the trajectories of all particles and their reactions with time. In the recent years, simulations based on the GFDE have been used extensively in biochemistry, notably to simulate biochemical networks in time and space and are often used as the "gold standard" to validate diffusion-reaction theories. The exact GFDE for partially diffusion-controlled reactions is difficult to use because of its complex form. Therefore, the radial Green's function, which is much simpler, is often used. Hence, much effort has been devoted to the sampling of the radial Green's functions, for which we have developed a sampling algorithm This algorithm only yields the inter-particle distance vector length after a time step; the sampling of the deviation angle of the inter-particle vector is not taken into consideration. In this work, we show that the radial distribution is predicted by the exact radial Green's function. We also use a technique developed by Clifford et al. to generate the inter-particle vector deviation angles, knowing the inter-particle vector length before and after a time step. The results are compared with those predicted by the exact GFDE and by the analytical angular functions for free diffusion. This first step in the creation of the radiation chemistry code should help the understanding of the contribution of the indirect effect in the

Wind Turbine Converter Control Interaction with Complex Wind Farm Systems

DEFF Research Database (Denmark)

Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

2013-01-01

. The same wind turbine converter control strategy is evaluated in two different wind farms. It is emphasised that the grid-side converter controller should be characterised by sufficient harmonic/noise rejection and adjusted depending on wind farms to which it is connected. Various stability indices......This study presents wind turbine converter stability analysis of wind farms in frequency domain. The interaction between the wind turbine control system and the wind farm structure in wind farms is deeply investigated. Two wind farms (i.e. Horns Rev II and Karnice) are taken into consideration...... in this study. It is shown that wind farm components, such as long high-voltage alternating current cables and park transformers, can introduce significant low-frequency series resonances seen from the wind turbine terminals that can affect wind turbine control system operation and overall wind farm stability...

Impacts of Interactive and Diagnostic Control System Use on the Innovation Process

Directory of Open Access Journals (Sweden)

Fábio Frezatti

2017-10-01

Full Text Available This research explores the innovation process in organizations based on the Management Control System (MCS. We examined the link between the diagnostic and interactive uses of management control systems and their association with the intensity of the innovation process. Motivations for the research are: (a enhance the potentiality of the model by including variables that are external to the organization, and (b offer an empirical emergent country perspective on innovation. The study is quantitative and the data were collected by means of a survey questionnaire involving a sample of 121 Brazilian companies. The analysis was supported by structural equation modeling. The contributions are: (a enhancement of the model by including the influences exerted by external stimuli on the intensity of innovation, (b confirmation of the utility of the model in an emergent country, and (c despite the controversial literature, highlighting the importance of the interactive use of the Management Control Systems process, by offering an empirical perspective on innovation control. A positive implication of the findings relates to the use of a broader and not exclusively internal model to increase its potentiality, reflecting the organizational reality by including the dynamism of external stimuli and the innovation control perspective.

Feasibility of interactive gesture control of a robotic microscope

Directory of Open Access Journals (Sweden)

Antoni Sven-Thomas

2015-09-01

Full Text Available Robotic devices become increasingly available in the clinics. One example are motorized surgical microscopes. While there are different scenarios on how to use the devices for autonomous tasks, simple and reliable interaction with the device is a key for acceptance by surgeons. We study, how gesture tracking can be integrated within the setup of a robotic microscope. In our setup, a Leap Motion Controller is used to track hand motion and adjust the field of view accordingly. We demonstrate with a survey that moving the field of view over a specified course is possible even for untrained subjects. Our results indicate that touch-less interaction with robots carrying small, near field gesture sensors is feasible and can be of use in clinical scenarios, where robotic devices are used in direct proximity of patient and physicians.

Pest control of aphids depends on landscape complexity and natural enemy interactions.

Science.gov (United States)

Martin, Emily A; Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

2015-01-01

Aphids are a major concern in agricultural crops worldwide, and control by natural enemies is an essential component of the ecological intensification of agriculture. Although the complexity of agricultural landscapes is known to influence natural enemies of pests, few studies have measured the degree of pest control by different enemy guilds across gradients in landscape complexity. Here, we use multiple natural-enemy exclosures replicated in 18 fields across a gradient in landscape complexity to investigate (1) the strength of natural pest control across landscapes, measured as the difference between pest pressure in the presence and in the absence of natural enemies; (2) the differential contributions of natural enemy guilds to pest control, and the nature of their interactions across landscapes. We show that natural pest control of aphids increased up to six-fold from simple to complex landscapes. In the absence of pest control, aphid population growth was higher in complex than simple landscapes, but was reduced by natural enemies to similar growth rates across all landscapes. The effects of enemy guilds were landscape-dependent. Particularly in complex landscapes, total pest control was supplied by the combined contribution of flying insects and ground-dwellers. Birds had little overall impact on aphid control. Despite evidence for intraguild predation of flying insects by ground-dwellers and birds, the overall effect of enemy guilds on aphid control was complementary. Understanding pest control services at large spatial scales is critical to increase the success of ecological intensification schemes. Our results suggest that, where aphids are the main pest of concern, interactions between natural enemies are largely complementary and lead to a strongly positive effect of landscape complexity on pest control. Increasing the availability of seminatural habitats in agricultural landscapes may thus benefit not only natural enemies, but also the effectiveness of

DNA Origami Directed Au Nanostar Dimers for Single-Molecule Surface-Enhanced Raman Scattering.

Science.gov (United States)

Tanwar, Swati; Haldar, Krishna Kanta; Sen, Tapasi

2017-12-06

We demonstrate the synthesis of Au nanostar dimers with tunable interparticle gap and controlled stoichiometry assembled on DNA origami. Au nanostars with uniform and sharp tips were immobilized on rectangular DNA origami dimerized structures to create nanoantennas containing monomeric and dimeric Au nanostars. Single Texas red (TR) dye was specifically attached in the junction of the dimerized origami to act as a Raman reporter molecule. The SERS enhancement factors of single TR dye molecules located in the conjunction region in dimer structures having interparticle gaps of 7 and 13 nm are 2 × 10 10 and 8 × 10 9 , respectively, which are strong enough for single analyte detection. The highly enhanced electromagnetic field generated by the plasmon coupling between sharp tips and cores of two Au nanostars in the wide conjunction region allows the accommodation and specific detection of large biomolecules. Such DNA-directed assembled nanoantennas with controlled interparticle separation distance and stoichiometry, and well-defined geometry, can be used as excellent substrates in single-molecule SERS spectroscopy and will have potential applications as a reproducible platform in single-molecule sensing.

Conceptual Modeling of the Influence of Wetting and Drying Cycles on Soil Aggregation and Stabilization

Science.gov (United States)

Albalasmeh, A. A.; Ghezzehei, T.

2011-12-01

Soil structure directly determines important soil physical properties including porosity, hydraulic conductivity, water retention, and mechanical strength and indirectly influences most biological and chemical processes that occur in and around soil. The interaction of environmental and biotic agents influences the physical condition of the soil, particularly through soil structural evolution. Wetting and drying cycles are important environmental processes known to enhance aggregation, while clay minerals, sesquioxides and soil organic matter (SOM) are the soil solids most involved in soil structural development. We hypothesize that drying of capillary water transports suspended and/or dissolved cementing agents toward inter-particle contacts and eventually deposits part of the colloidal mass forming inter-particle bonds. Here, we will show the role of wetting and drying cycles on soil aggregation and stabilization and how these cycles transport and deposit organic cementing agents at the inter-particle contact. We will present results of the effect of particle size, number of wetting and drying cycles, viscosity, molecule length and concentration of suspended and/or dissolved cementing agents on soil aggregation and stabilization.

Collisional shifts in optical-lattice atom clocks

International Nuclear Information System (INIS)

Band, Y. B.; Vardi, A.

2006-01-01

We theoretically study the effects of elastic collisions on the determination of frequency standards via Ramsey-fringe spectroscopy in optical-lattice atom clocks. Interparticle interactions of bosonic atoms in multiply occupied lattice sites can cause a linear frequency shift, as well as generate asymmetric Ramsey-fringe patterns and reduce fringe visibility due to interparticle entanglement. We propose a method of reducing these collisional effects in an optical lattice by introducing a phase difference of π between the Ramsey driving fields in adjacent sites. This configuration suppresses site-to-site hopping due to interference of two tunneling pathways, without degrading fringe visibility. Consequently, the probability of double occupancy is reduced, leading to cancellation of collisional shifts

Relativistic n-body wave equations in scalar quantum field theory

International Nuclear Information System (INIS)

Emami-Razavi, Mohsen

2006-01-01

The variational method in a reformulated Hamiltonian formalism of Quantum Field Theory (QFT) is used to derive relativistic n-body wave equations for scalar particles (bosons) interacting via a massive or massless mediating scalar field (the scalar Yukawa model). Simple Fock-space variational trial states are used to derive relativistic n-body wave equations. The equations are shown to have the Schroedinger non-relativistic limits, with Coulombic interparticle potentials in the case of a massless mediating field and Yukawa interparticle potentials in the case of a massive mediating field. Some examples of approximate ground state solutions of the n-body relativistic equations are obtained for various strengths of coupling, for both massive and massless mediating fields

Spectrophotometric Determination of 4-Hydroxy-2-mercapto-6-methylpyrimidine Based on Aggregation of Colloidal Gold Nanoparticles

Directory of Open Access Journals (Sweden)

M.Reza Hormozi-Nezhad

2014-12-01

Full Text Available We report herein the development of a highly sensitive colorimetric method for the detection of 4-hydroxy-2-mercapto-6-methylpyrimidine (MTU which acts as an anti-thyroid drug utilizing citrate capped gold nanoparticles (Au-NPs. This thiol-containing molecule exhibits intriguing affinity with Au-NPs. The reactivity involves the displacement of the citrate shell by the thiolate shell followed by intermolecular electrostatic interactions or hydrogen-bonding between the thiolate shells. The interparticle interactions depend on ionic strength, pH and Au-NPs concentration of the solution. The interparticle interactions lead to a small change in the plasmon band around 521 nm and the formation of a new red shifted band. The calibration curve is derived from the ratio of the absorption intensity changes at 650 nm to the changes at 520 nm. It was linear in the concentration range of 5.0 × 10-7-2.75 × 10-6 M. The detection limit (3σ for MTU was found to be 1.9 × 10-7 M.

Controlled gas-liquid interfacial plasmas for synthesis of nano-bio-carbon conjugate materials

Science.gov (United States)

Kaneko, Toshiro; Hatakeyama, Rikizo

2018-01-01

Plasmas generated in contact with a liquid have been recognized to be a novel reactive field in nano-bio-carbon conjugate creation because several new chemical reactions have been yielded at the gas-liquid interface, which were induced by the physical dynamics of non-equilibrium plasmas. One is the ion irradiation to a liquid, which caused the spatially selective dissociation of the liquid and the generation of additive reducing and oxidizing agents, resulting in the spatially controlled synthesis of nanostructures. The other is the electron irradiation to a liquid, which directly enhanced the reduction action at the plasma-liquid interface, resulting in temporally controlled nanomaterial synthesis. Using this novel reaction field, gold nanoparticles with controlled interparticle distance were synthesized using carbon nanotubes as a template. Furthermore, nanoparticle-biomolecule conjugates and nanocarbon-biomolecule conjugates were successfully synthesized by an aqueous-solution contact plasma and an electrolyte plasma, respectively, which were rapid and low-damage processes suitable for nano-bio-carbon conjugate materials.

Data on the interaction between thermal comfort and building control research.

Science.gov (United States)

Park, June Young; Nagy, Zoltan

2018-04-01

This dataset contains bibliography information regarding thermal comfort and building control research. In addition, the instruction of a data-driven literature survey method guides readers to reproduce their own literature survey on related bibliography datasets. Based on specific search terms, all relevant bibliographic datasets are downloaded. We explain the keyword co-occurrences of historical developments and recent trends, and the citation network which represents the interaction between thermal comfort and building control research. Results and discussions are described in the research article entitled "Comprehensive analysis of the relationship between thermal comfort and building control research - A data-driven literature review" (Park and Nagy, 2018).

Targeting protein-protein interactions for parasite control.

Directory of Open Access Journals (Sweden)

Christina M Taylor

2011-04-01

Full Text Available Finding new drug targets for pathogenic infections would be of great utility for humanity, as there is a large need to develop new drugs to fight infections due to the developing resistance and side effects of current treatments. Current drug targets for pathogen infections involve only a single protein. However, proteins rarely act in isolation, and the majority of biological processes occur via interactions with other proteins, so protein-protein interactions (PPIs offer a realm of unexplored potential drug targets and are thought to be the next-generation of drug targets. Parasitic worms were chosen for this study because they have deleterious effects on human health, livestock, and plants, costing society billions of dollars annually and many sequenced genomes are available. In this study, we present a computational approach that utilizes whole genomes of 6 parasitic and 1 free-living worm species and 2 hosts. The species were placed in orthologous groups, then binned in species-specific orthologous groups. Proteins that are essential and conserved among species that span a phyla are of greatest value, as they provide foundations for developing broad-control strategies. Two PPI databases were used to find PPIs within the species specific bins. PPIs with unique helminth proteins and helminth proteins with unique features relative to the host, such as indels, were prioritized as drug targets. The PPIs were scored based on RNAi phenotype and homology to the PDB (Protein DataBank. EST data for the various life stages, GO annotation, and druggability were also taken into consideration. Several PPIs emerged from this study as potential drug targets. A few interactions were supported by co-localization of expression in M. incognita (plant parasite and B. malayi (H. sapiens parasite, which have extremely different modes of parasitism. As more genomes of pathogens are sequenced and PPI databases expanded, this methodology will become increasingly

Achieving atomistic control in materials processing by plasma–surface interactions

International Nuclear Information System (INIS)

Chang, Jeffrey; Chang, Jane P

2017-01-01

The continuous down-scaling of electronic devices and the introduction of functionally improved novel materials require a greater atomic level controllability in the synthesis and patterning of thin film materials, especially with regards to deposition uniformity and conformality as well as etching selectivity and anisotropy. The richness of plasma chemistry and the corresponding plasma–surface interactions provide the much needed processing flexibility and efficacy. To achieve the integration of the novel materials into devices, plasma-enhanced atomic layer processing techniques are emerging as the enabling factors to obtain atomic scale control of complex materials and nanostructures. This review focuses on an overview of the role of respective plasma species involved in plasma–surface interactions, addressing their respective and synergistic effects, which is followed by two distinct applications: plasma-enhanced atomic layer deposition (ALD) and atomic layer etching (ALE). For plasma-enhanced ALD, this review emphasizes the use of plasma chemistry to enable alternative pathways to synthesize complex materials at low temperatures and the challenges associated with deposition conformality. For plasma enabled ALE processes, the review focuses on the surface-specific chemical reactions needed to achieve desirable selectivity and anisotropy. (topical review)

New Advancements in the Study of the Uniform Electron Gas with Full Configuration Interaction Quantum Monte Carlo

Science.gov (United States)

Ruggeri, Michele; Luo, Hongjun; Alavi, Ali

Full Configuration Interaction Quantum Monte Carlo (FCIQMC) is able to give remarkably accurate results in the study of atoms and molecules. The study of the uniform electron gas (UEG) on the other hand has proven to be much harder, particularly in the low density regime. The source of this difficulty comes from the strong interparticle correlations that arise at low density, and essentially forbid the study of the electron gas in proximity of Wigner crystallization. We extend a previous study on the three dimensional electron gas computing the energy of a fully polarized gas for N=27 electrons at high and medium density (rS = 0 . 5 to 5 . 0). We show that even when dealing with a polarized UEG the computational cost of the study of systems with rS > 5 . 0 is prohibitive; in order to deal with correlations and to extend the density range that to be studied we introduce a basis of localized states and an effective transcorrelated Hamiltonian.

Dynamic depletion attraction between colloids suspended in a phase-separating binary liquid mixture

International Nuclear Information System (INIS)

Araki, Takeaki; Tanaka, Hajime

2008-01-01

Understanding interactions between colloids (or nanoparticles) immersed in a phase-separating binary mixture is of both fundamental and technological importance. Here we report a novel type of interparticle attractive interaction of a purely dynamic origin, which is found by a coarse-grained numerical simulation. Due to surface wetting effects, there are strong diffusion fluxes towards particles just after the initiation of phase separation of the matrix binary liquid mixture. The flux in the region between particles soon becomes weaker than that in the other regions since the depletion zones formed around particles overlap selectively between the particles. The resulting imbalance of the diffusion flux induces interparticle attractive interactions, i.e., the osmotic force pushes particles closer. We confirm that this wetting-induced 'dynamic' depletion force can be stronger than a van der Waals force and a capillary force that is induced by the interfacial tension, and thus plays a dominant role in the early stage of particle aggregation. We note that this novel interaction originating from the momentum conservation law may be generic to particles acting as diffusional sinks or sources. (fast track communication)

The Efficacy of Parent-Child Interaction Therapy with Chinese Families: Randomized Controlled Trial

Science.gov (United States)

Leung, Cynthia; Tsang, Sandra; Sin, Tammy C. S.; Choi, Siu-yan

2015-01-01

Objective: This study aimed to examine the efficacy of the Parent-Child Interaction Therapy (PCIT) in Hong Kong Chinese families, using randomized controlled trial design. Methods: The participants included 111 Hong Kong Chinese parents with children aged 2--7 years old, who were randomized into the intervention group (n = 54) and control group (n…

Capillary interactions in nano-particle suspensions

International Nuclear Information System (INIS)

Bossev, D.P.; Warren, G.

2009-01-01

We have investigated the structures formed by colloidal particles suspended in solvents at volume fractions below 10% and interacting through capillary bridges. Such systems resemble colloidal gas of sticky nano-spheres that form pearl-necklace like chains that, in turn, induce strong viscoelasticity due to the formation of 3-D fractal network. The capillary force dominates the electrostatic and Van der Waals forces in solutions and can bridge multiple particles depending of the volume of the capillary bridge. We have investigated the morphology of the structures formed at different fractions of the bridging fluid. Small-angle neutron scattering (SANS) is used to study nanoparticles with an average diameter of 10 nm in polar and non-polar organic solvents at ambient temperatures. SANS intensity as a function of the scattering vector is analyzed as a product of a form factor, that depends on the particle shape, and a structure factor, that characterizes the interparticle inter reactions. The interaction of particles in polar solvents is considered to be through electrostatic repulsion and the data is successfully fitted by Hayter-Penfold mean spherical approximation (HPMSA). Computer simulations of a pearl necklace-like chain of spheres is conducted to explain the structure factor when capillary bridges are present. Alternatively, we have analyzed the slope of the intensity at low scattering vector in a double logarithmic plot to determine the dimension of the fractal structures formed by the particles at different volume fraction of the bridging fluid. We have also studied the properties of the capillary bridge between a pair of particles. The significance of this study is to explore the possibility of using capillary force as a tool to engineer new colloidal structures and materials in solutions and to optimize their viscoelastic properties. (author)

Team interaction skills evaluation criteria for nuclear power plant control room operators

International Nuclear Information System (INIS)

Montgomery, J.; Gaddy, C.; Toquam, J.

1991-01-01

This paper reports on previous research which has shown the value of good team interaction skills to group performance, yet little progress has been made in measuring such skills. Dimensions of team interaction skills developed in an earlier study were extensively revised and cast into a Behaviorally anchored Rating scales (BARS) and a Behavioral Frequency scale format. Rating data were collected using training instructors at a nuclear plant, who rated videotape scenarios of control room performance and later rated control room crews during requalification training. High levels of interrater agreement on both rating scales was, although the hypothesized factor structure did not emerge. Analysis of ratings of the videotapes using Cronbach's components of accuracy indicted that BARS ratings generally exhibited less error than did the Behavioral Frequency ratings. This paper discusses results in terms of both field and research implications

Utilization and control of ecological interactions in polymicrobial infections and community-based microbial cell factories

DEFF Research Database (Denmark)

Wigneswaran, Vinoth; Amador Hierro, Cristina Isabel; Jelsbak, Lotte

2016-01-01

Microbial activities are most often shaped by interactions between co-existing microbes within mixed-species communities. Dissection of the molecular mechanisms of species interactions within communities is a central issue in microbial ecology, and our ability to engineer and control microbial co...

Using interactive problem-solving techniques to enhance control systems education for non English-speakers

Science.gov (United States)

Lamont, L. A.; Chaar, L.; Toms, C.

2010-03-01

Interactive learning is beneficial to students in that it allows the continual development and testing of many skills. An interactive approach enables students to improve their technical capabilities, as well as developing both verbal and written communicative ability. Problem solving and communication skills are vital for engineering students; in the workplace they will be required to communicate with people of varying technical abilities and from different linguistic and engineering backgrounds. In this paper, a case study is presented that discusses how the traditional method of teaching control systems can be improved. 'Control systems' is a complex engineering topic requiring students to process an extended amount of mathematical formulae. MATLAB software, which enables students to interactively compare a range of possible combinations and analyse the optimal solution, is used to this end. It was found that students became more enthusiastic and interested when given ownership of their learning objectives. As well as improving the students' technical knowledge, other important engineering skills are also improved by introducing an interactive method of teaching.

Specific interactions between DNA and regulatory protein controlled by ligand-binding: Ab initio molecular simulation

Energy Technology Data Exchange (ETDEWEB)

Matsushita, Y., E-mail: kurita@cs.tut.ac.jp; Murakawa, T., E-mail: kurita@cs.tut.ac.jp; Shimamura, K., E-mail: kurita@cs.tut.ac.jp; Oishi, M., E-mail: kurita@cs.tut.ac.jp; Ohyama, T., E-mail: kurita@cs.tut.ac.jp; Kurita, N., E-mail: kurita@cs.tut.ac.jp [Department of Computer Science and Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi, 441-8580 (Japan)

2015-02-27

The catabolite activator protein (CAP) is one of the regulatory proteins controlling the transcription mechanism of gene. Biochemical experiments elucidated that the complex of CAP with cyclic AMP (cAMP) is indispensable for controlling the mechanism, while previous molecular simulations for the monomer of CAP+cAMP complex revealed the specific interactions between CAP and cAMP. However, the effect of cAMP-binding to CAP on the specific interactions between CAP and DNA is not elucidated at atomic and electronic levels. We here considered the ternary complex of CAP, cAMP and DNA in solvating water molecules and investigated the specific interactions between them at atomic and electronic levels using ab initio molecular simulations based on classical molecular dynamics and ab initio fragment molecular orbital methods. The results highlight the important amino acid residues of CAP for the interactions between CAP and cAMP and between CAP and DNA.

Specific interactions between DNA and regulatory protein controlled by ligand-binding: Ab initio molecular simulation

International Nuclear Information System (INIS)

Matsushita, Y.; Murakawa, T.; Shimamura, K.; Oishi, M.; Ohyama, T.; Kurita, N.

2015-01-01

The catabolite activator protein (CAP) is one of the regulatory proteins controlling the transcription mechanism of gene. Biochemical experiments elucidated that the complex of CAP with cyclic AMP (cAMP) is indispensable for controlling the mechanism, while previous molecular simulations for the monomer of CAP+cAMP complex revealed the specific interactions between CAP and cAMP. However, the effect of cAMP-binding to CAP on the specific interactions between CAP and DNA is not elucidated at atomic and electronic levels. We here considered the ternary complex of CAP, cAMP and DNA in solvating water molecules and investigated the specific interactions between them at atomic and electronic levels using ab initio molecular simulations based on classical molecular dynamics and ab initio fragment molecular orbital methods. The results highlight the important amino acid residues of CAP for the interactions between CAP and cAMP and between CAP and DNA

Single-step controlled-NOT logic from any exchange interaction

Science.gov (United States)

Galiautdinov, Andrei

2007-11-01

A self-contained approach to studying the unitary evolution of coupled qubits is introduced, capable of addressing a variety of physical systems described by exchange Hamiltonians containing Rabi terms. The method automatically determines both the Weyl chamber steering trajectory and the accompanying local rotations. Particular attention is paid to the case of anisotropic exchange with tracking controls, which is solved analytically. It is shown that, if computational subspace is well isolated, any exchange interaction can always generate high fidelity, single-step controlled-NOT (CNOT) logic, provided that both qubits can be individually manipulated. The results are then applied to superconducting qubit architectures, for which several CNOT gate implementations are identified. The paper concludes with consideration of two CNOT gate designs having high efficiency and operating with no significant leakage to higher-lying noncomputational states.

Interaction between bacterial outer membrane proteins and periplasmic quality control factors: a kinetic partitioning mechanism.

Science.gov (United States)

Wu, Si; Ge, Xi; Lv, Zhixin; Zhi, Zeyong; Chang, Zengyi; Zhao, Xin Sheng

2011-09-15

The OMPs (outer membrane proteins) of Gram-negative bacteria have to be translocated through the periplasmic space before reaching their final destination. The aqueous environment of the periplasmic space and high permeability of the outer membrane engender such a translocation process inevitably challenging. In Escherichia coli, although SurA, Skp and DegP have been identified to function in translocating OMPs across the periplasm, their precise roles and their relationship remain to be elucidated. In the present paper, by using fluorescence resonance energy transfer and single-molecule detection, we have studied the interaction between the OMP OmpC and these periplasmic quality control factors. The results of the present study reveal that the binding rate of OmpC to SurA or Skp is much faster than that to DegP, which may lead to sequential interaction between OMPs and different quality control factors. Such a kinetic partitioning mechanism for the chaperone-substrate interaction may be essential for the quality control of the biogenesis of OMPs.

A discrete model of Ostwald ripening based on multiple pairwise interactions

Science.gov (United States)

Di Nunzio, Paolo Emilio

2018-06-01

A discrete multi-particle model of Ostwald ripening based on direct pairwise interactions is developed for particles with incoherent interfaces as an alternative to the classical LSW mean field theory. The rate of matter exchange depends on the average surface-to-surface interparticle distance, a characteristic feature of the system which naturally incorporates the effect of volume fraction of second phase. The multi-particle diffusion is described through the definition of an interaction volume containing all the particles involved in the exchange of solute. At small volume fractions this is proportional to the size of the central particle, at higher volume fractions it gradually reduces as a consequence of diffusion screening described on a geometrical basis. The topological noise present in real systems is also included. For volume fractions below about 0.1 the model predicts broad and right-skewed stationary size distributions resembling a lognormal function. Above this value, a transition to sharper, more symmetrical but still right-skewed shapes occurs. An excellent agreement with experiments is obtained for 3D particle size distributions of solid-solid and solid-liquid systems with volume fraction 0.07, 0.30, 0.52 and 0.74. The kinetic constant of the model depends on the cube root of volume fraction up to about 0.1, then increases rapidly with an upward concavity. It is in good agreement with the available literature data on solid-liquid mixtures in the volume fraction range from 0.20 to about 0.75.

Online Assessment of Human-Robot Interaction for Hybrid Control of Walking

Directory of Open Access Journals (Sweden)

Ana de-los-Reyes

2011-12-01

Full Text Available Restoration of walking ability of Spinal Cord Injury subjects can be achieved by different approaches, as the use of robotic exoskeletons or electrical stimulation of the user’s muscles. The combined (hybrid approach has the potential to provide a solution to the drawback of each approach. Specific challenges must be addressed with specific sensory systems and control strategies. In this paper we present a system and a procedure to estimate muscle fatigue from online physical interaction assessment to provide hybrid control of walking, regarding the performances of the muscles under stimulation.

Observation and Control of Hamiltonian Chaos in Wave-particle Interaction

International Nuclear Information System (INIS)

Doveil, F.; Ruzzon, A.; Elskens, Y.

2010-01-01

Wave-particle interactions are central in plasma physics. The paradigm beam-plasma system can be advantageously replaced by a traveling wave tube (TWT) to allow their study in a much less noisy environment. This led to detailed analysis of the self-consistent interaction between unstable waves and an either cold or warm electron beam. More recently a test cold beam has been used to observe its interaction with externally excited wave(s). This allowed observing the main features of Hamiltonian chaos and testing a new method to efficiently channel chaotic transport in phase space. To simulate accurately and efficiently the particle dynamics in the TWT and other 1D particle-wave systems, a new symplectic, symmetric, second order numerical algorithm is developed, using particle position as the independent variable, with a fixed spatial step.This contribution reviews: presentation of the TWT and its connection to plasma physics, resonant interaction of a charged particle in electrostatic waves, observation of particle trapping and transition to chaos, test of control of chaos, and description of the simulation algorithm.The velocity distribution function of the electron beam is recorded with a trochoidal energy analyzer at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the 4m long helix of the TWT. The nonlinear synchronization of particles by a single wave, responsible for Landau damping, is observed. We explore the resonant velocity domain associated with a single wave as well as the transition to large scale chaos when the resonant domains of two waves and their secondary resonances overlap. This transition exhibits a devil's staircase behavior when increasing the excitation level in agreement with numerical simulation.A new strategy for control of chaos by building barriers of transport in phase space as well as its robustness is successfully tested. The underlying concepts extend far beyond the field of

Formation and relaxation of quasistationary states in particle systems with power-law interactions.

Science.gov (United States)

Marcos, B; Gabrielli, A; Joyce, M

2017-09-01

We explore the formation and relaxation of the so-called quasistationary states (QSS) for particle distributions in three dimensions interacting via an attractive radial pair potential V(r→∞)∼1/r^{γ} with γ>0, and either a soft core or hard core regularization at small r. In the first part of the paper, we generalize, for any spatial dimension d≥2, Chandrasekhar's approach for the case of gravity to obtain analytic estimates of the rate of collisional relaxation due to two-body collisions. The resultant relaxation rates indicate an essential qualitative difference depending on the integrability of the pair force at large distances: for γ>d-1, the rate diverges in the large particle number N (mean-field) limit, unless a sufficiently large soft core is present; for γsoft cores leading to the formation of QSS. We find, just as for the previously well studied case of gravity (which we also revisit), excellent agreement between the parametric dependence of the observed relaxation times and our analytic predictions. Further, as in the case of gravity, we find that the results indicate that, when large impact factors dominate, the appropriate cutoff is the size of the system (rather than, for example, the mean interparticle distance). Our results provide strong evidence that the existence of QSS is robust only for long-range interactions with a large distance behavior γinteraction.

Surface effects on the magnetic behavior of nanocrystalline nickel ferrites and nickel ferrite-polymer nanocomposites

International Nuclear Information System (INIS)

Nathani, H.; Misra, R.D.K.

2004-01-01

The magnetization studies on nanocrystalline nickel ferrite as powder particles, and as diluted dispersion (10 wt.%) in polymer matrix (polymer nanocomposites) are presented. The two polymer-based nanocomposites were prepared via ball-milling and in situ polymerization, respectively. The magnetization measurements provide strong evidence of surface effects to magnetization, which explains the non-saturation of magnetization at high fields. The differences in the magnetization behavior of nickel ferrite as powder particles and in the ball-milled nanocomposite and the nanocomposite prepared via in situ polymerization are attributed to the different extent of interparticle interactions between the particles and the preparation route. The magnetization versus applied field behavior of the three ferrite systems show a similar jump in the initial part of the magnetization curve in all the cases which implies the existence of a core-shell like morphology of the particles over a large temperature range and its dominance over the interparticle interaction effects between the particles

Trichoderma-plant-pathogen interactions: advances in genetics of biological control.

Science.gov (United States)

Mukherjee, Mala; Mukherjee, Prasun K; Horwitz, Benjamin A; Zachow, Christin; Berg, Gabriele; Zeilinger, Susanne

2012-12-01

Trichoderma spp. are widely used in agriculture as biofungicides. Induction of plant defense and mycoparasitism (killing of one fungus by another) are considered to be the most important mechanisms of Trichoderma-mediated biological control. Understanding these mechanisms at the molecular level would help in developing strains with superior biocontrol properties. In this article, we review our current understanding of the genetics of interactions of Trichoderma with plants and plant pathogens.

An optimal control method for fluid structure interaction systems via adjoint boundary pressure

Science.gov (United States)

Chirco, L.; Da Vià, R.; Manservisi, S.

2017-11-01

In recent year, in spite of the computational complexity, Fluid-structure interaction (FSI) problems have been widely studied due to their applicability in science and engineering. Fluid-structure interaction systems consist of one or more solid structures that deform by interacting with a surrounding fluid flow. FSI simulations evaluate the tensional state of the mechanical component and take into account the effects of the solid deformations on the motion of the interior fluids. The inverse FSI problem can be described as the achievement of a certain objective by changing some design parameters such as forces, boundary conditions and geometrical domain shapes. In this paper we would like to study the inverse FSI problem by using an optimal control approach. In particular we propose a pressure boundary optimal control method based on Lagrangian multipliers and adjoint variables. The objective is the minimization of a solid domain displacement matching functional obtained by finding the optimal pressure on the inlet boundary. The optimality system is derived from the first order necessary conditions by taking the Fréchet derivatives of the Lagrangian with respect to all the variables involved. The optimal solution is then obtained through a standard steepest descent algorithm applied to the optimality system. The approach presented in this work is general and could be used to assess other objective functionals and controls. In order to support the proposed approach we perform a few numerical tests where the fluid pressure on the domain inlet controls the displacement that occurs in a well defined region of the solid domain.

Interaction force and motion estimators facilitating impedance control of the upper limb rehabilitation robot.

Science.gov (United States)

Mancisidor, Aitziber; Zubizarreta, Asier; Cabanes, Itziar; Bengoa, Pablo; Jung, Je Hyung

2017-07-01

In order to enhance the performance of rehabilitation robots, it is imperative to know both force and motion caused by the interaction between user and robot. However, common direct measurement of both signals through force and motion sensors not only increases the complexity of the system but also impedes affordability of the system. As an alternative of the direct measurement, in this work, we present new force and motion estimators for the proper control of the upper-limb rehabilitation Universal Haptic Pantograph (UHP) robot. The estimators are based on the kinematic and dynamic model of the UHP and the use of signals measured by means of common low-cost sensors. In order to demonstrate the effectiveness of the estimators, several experimental tests were carried out. The force and impedance control of the UHP was implemented first by directly measuring the interaction force using accurate extra sensors and the robot performance was compared to the case where the proposed estimators replace the direct measured values. The experimental results reveal that the controller based on the estimators has similar performance to that using direct measurement (less than 1 N difference in root mean square error between two cases), indicating that the proposed force and motion estimators can facilitate implementation of interactive controller for the UHP in robotmediated rehabilitation trainings.

Nonlinear PI Control with Adaptive Interaction Algorithm for Multivariable Wastewater Treatment Process

Directory of Open Access Journals (Sweden)

S. I. Samsudin

2014-01-01

Full Text Available The wastewater treatment plant (WWTP is highly known with the nonlinearity of the control parameters, thus it is difficult to be controlled. In this paper, the enhancement of nonlinear PI controller (ENon-PI to compensate the nonlinearity of the activated sludge WWTP is proposed. The ENon-PI controller is designed by cascading a sector-bounded nonlinear gain to linear PI controller. The rate variation of the nonlinear gain kn is automatically updated based on adaptive interaction algorithm. Initiative to simplify the ENon-PI control structure by adapting kn has been proved by significant improvement under various dynamic influents. More than 30% of integral square error and 14% of integral absolute error are reduced compared to benchmark PI for DO control and nitrate in nitrogen removal control. Better average effluent qualities, less number of effluent violations, and lower aeration energy consumption resulted.

Energy cascading by triple-bubble interactions via time-delayed control

International Nuclear Information System (INIS)

Lin, Yen-Liang; Chang, Chia-Ming; Tseng, Fan-Gang; Yang, I-Da; Chieng, Ching-Chang

2012-01-01

The triple-bubble interaction controlled by a precise time-delayed technique was investigated in detail with respect to different ignition times, heater spaces and sequential firing modes to promote efficient energy cascading and concentration. The target bubble, which was generated under a specific delay time with two auxiliary bubbles, can have a volume that is two or almost three times larger than that of a single bubble. This result overcomes the limitation of energy usage on an explosive microbubble under a constant heat flux. As the heater space decreases, stronger bubble–bubble interactions were obtained due to the hydrodynamic effect and the intensive pressure wave emission, resulting in highly enhancing and depressing bubble dynamics. Other interesting phenomena, such as bubble shifting, mushroom-shape bubble, rod-shape bubble and bubble extension among heaters, were also recorded by a high-speed phase-averaged stroboscopic technique, displaying special non-spherical bubble dynamics. Artificial manipulation of bubble behavior was further conducted in a two-level sequential firing process. Using various volumetric combinations, the adjustable multi-level fluid transportation can be realized by a digital time-delayed control. The above-mentioned information can be applied to not only the design and operation of inkjet printheads but also cavitation research and fluid pumping in microdevices. (paper)

Affiliation and control in marital interaction: interpersonal complementarity is present but is not associated with affect or relationship quality.

Science.gov (United States)

Cundiff, Jenny M; Smith, Timothy W; Butner, Jonathan; Critchfield, Kenneth L; Nealey-Moore, Jill

2015-01-01

The principle of complementarity in interpersonal theory states that an actor's behavior tends to "pull, elicit, invite, or evoke" responses from interaction partners who are similar in affiliation (i.e., warmth vs. hostility) and opposite in control (i.e., dominance vs. submissiveness). Furthermore, complementary interactions are proposed to evoke less negative affect and promote greater relationship satisfaction. These predictions were examined in two studies of married couples. Results suggest that complementarity in affiliation describes a robust general pattern of marital interaction, but complementarity in control varies across contexts. Consistent with behavioral models of marital interaction, greater levels of affiliation and lower control by partners-not complementarity in affiliation or control-were associated with less anger and anxiety and greater relationship quality. Partners' levels of affiliation and control combined in ways other than complementarity-mostly additively, but sometimes synergistically-to predict negative affect and relationship satisfaction. © 2014 by the Society for Personality and Social Psychology, Inc.

Solvable Model of a Generic Trapped Mixture of Interacting Bosons: Many-Body and Mean-Field Properties

Science.gov (United States)

Klaiman, S.; Streltsov, A. I.; Alon, O. E.

2018-04-01

A solvable model of a generic trapped bosonic mixture, N 1 bosons of mass m 1 and N 2 bosons of mass m 2 trapped in an harmonic potential of frequency ω and interacting by harmonic inter-particle interactions of strengths λ 1, λ 2, and λ 12, is discussed. It has recently been shown for the ground state [J. Phys. A 50, 295002 (2017)] that in the infinite-particle limit, when the interaction parameters λ 1(N 1 ‑ 1), λ 2(N 2 ‑ 1), λ 12 N 1, λ 12 N 2 are held fixed, each of the species is 100% condensed and its density per particle as well as the total energy per particle are given by the solution of the coupled Gross-Pitaevskii equations of the mixture. In the present work we investigate properties of the trapped generic mixture at the infinite-particle limit, and find differences between the many-body and mean-field descriptions of the mixture, despite each species being 100%. We compute analytically and analyze, both for the mixture and for each species, the center-of-mass position and momentum variances, their uncertainty product, the angular-momentum variance, as well as the overlap of the exact and Gross-Pitaevskii wavefunctions of the mixture. The results obtained in this work can be considered as a step forward in characterizing how important are many-body effects in a fully condensed trapped bosonic mixture at the infinite-particle limit.

Electric excitations in liquid He4 and their role in neutron scattering spectrum

International Nuclear Information System (INIS)

Poluehktov, Yu.M.; Karnatsevich, L.V.

2001-01-01

Data of experiments on excitation spectrum in liquid He 4 by inelastic neutron scattering method are discussed. Exact solution of particle scattering in ideal Bose-gas is given. Influence of inter-particle interactions on the structure of many-particle Bose system is analysed qualitatively. 55 refs., 1 figs

Control of proton beam divergence in intense-laser foil-plasma interaction

International Nuclear Information System (INIS)

Kawata, S.; Sonobe, R.; Miyazaki, S.; Sakai, K.; Kikuchi, T.

2006-01-01

Quality of an ion beam is one of the critical factors in intense-laser ion beam generation. A purpose of this study is the suppression of transverse proton divergence by a controlled electron cloud in laser-foil interactions. In this study, the foil target has a hole at the opposite side of the laser illumination. The electrons accelerated by an intense laser are limited in transverse by a neutral plasma at a protuberant part. Therefore the protons are accelerated and also controlled transversely by the electron cloud structure. In our 2.5-dimensional Particle-in-Cell simulations we demonstrate that the transverse shape of the electron cloud is well controlled and the collimated proton beam is generated successfully in the target with the hole. (authors)

Optical response of a quantum dot-metal nanoparticle hybrid interacting with a weak probe field.

Science.gov (United States)

Kosionis, Spyridon G; Terzis, Andreas F; Sadeghi, Seyed M; Paspalakis, Emmanuel

2013-01-30

We study optical effects in a hybrid system composed of a semiconductor quantum dot and a spherical metal nanoparticle that interacts with a weak probe electromagnetic field. We use modified nonlinear density matrix equations for the description of the optical properties of the system and obtain a closed-form expression for the linear susceptibilities of the quantum dot, the metal nanoparticle, and the total system. We then investigate the dependence of the susceptibility on the interparticle distance as well as on the material parameters of the hybrid system. We find that the susceptibility of the quantum dot exhibits optical transparency for specific frequencies. In addition, we show that there is a range of frequencies of the applied field for which the susceptibility of the semiconductor quantum dot leads to gain. This suggests that in such a hybrid system quantum coherence can reverse the course of energy transfer, allowing flow of energy from the metallic nanoparticle to the quantum dot. We also explore the susceptibility of the metal nanoparticle and show that it is strongly influenced by the presence of the quantum dot.

Compliance control based on PSO algorithm to improve the feeling during physical human-robot interaction.

Science.gov (United States)

Jiang, Zhongliang; Sun, Yu; Gao, Peng; Hu, Ying; Zhang, Jianwei

2016-01-01

Robots play more important roles in daily life and bring us a lot of convenience. But when people work with robots, there remain some significant differences in human-human interactions and human-robot interaction. It is our goal to make robots look even more human-like. We design a controller which can sense the force acting on any point of a robot and ensure the robot can move according to the force. First, a spring-mass-dashpot system was used to describe the physical model, and the second-order system is the kernel of the controller. Then, we can establish the state space equations of the system. In addition, the particle swarm optimization algorithm had been used to obtain the system parameters. In order to test the stability of system, the root-locus diagram had been shown in the paper. Ultimately, some experiments had been carried out on the robotic spinal surgery system, which is developed by our team, and the result shows that the new controller performs better during human-robot interaction.

Thermal expansion and its impacts on thermal transport in the FPU-α-β model

Directory of Open Access Journals (Sweden)

Xiaodong Cao

2015-05-01

Full Text Available We study the impacts of thermal expansion, arising from the asymmetric interparticle potential, on thermal conductance in the FPU-α-β model. A nonmonotonic dependence of the temperature gradient and thermal conductance on the cubic interaction parameter α are shown, which corresponds to the variation of the coefficient of thermal expansion. Three domains with respect to α can be identified. The results are explained based on the detailed analysis of the asymmetry of the interparticle potential. The self-consistent phonon theory, which can capture the effect of thermal expansion, is developed to support our explanation in a quantitative way. Our result would be helpful to understand the issue that whether there exist normal thermal conduction in the FPU-α-β model.

Water pollution control in river basin by interactive fuzzy interval multiobjective programming

Energy Technology Data Exchange (ETDEWEB)

Chang, N.B.; Chen, H.W. [National Cheng-Kung Univ., Tainan (Taiwan, Province of China). Dept. of Environmental Engineering; Shaw, D.G.; Yang, C.H. [Academia Sinica, Taipei (Taiwan, Province of China). Inst. of Economics

1997-12-01

The potential conflict between protection of water quality and economic development by different uses of land within river basins is a common problem in regional planning. Many studies have applied multiobjective decision analysis under uncertainty to problems of this kind. This paper presents the interactive fuzzy interval multiobjective mixed integer programming (IFIMOMIP) model to evaluate optimal strategies of wastewater treatment levels within a river system by considering the uncertainties in decision analysis. The interactive fuzzy interval multiobjective mixed integer programming approach is illustrated in a case study for the evaluation of optimal wastewater treatment strategies for water pollution control in a river basin. In particular, it demonstrates how different types of uncertainty in a water pollution control system can be quantified and combined through the use of interval numbers and membership functions. The results indicate that such an approach is useful for handling system complexity and generating more flexible policies for water quality management in river basins.

Competitive interactions and controlled release of a natural antioxidant from halloysite nanotubes.

Science.gov (United States)

Hári, József; Gyürki, Ádám; Sárközi, Márk; Földes, Enikő; Pukánszky, Béla

2016-01-15

Halloysite nanotubes used as potential carrier material for a controlled release stabilizer in polyethylene were thoroughly characterized with several techniques including the measurement of specific surface area, pore volume and surface energy. The high surface energy of the halloysite results in the strong bonding of the additive to the surface. Dissolution experiments carried out with eight different solvents for the determination of the effect of solvent characteristics on the amount of irreversibly bonded quercetin proved that adsorption and dissolution depend on competitive interactions prevailing in the system. Solvents with low polarity dissolve only surplus quercetin adsorbed in multilayers. Polyethylene is a very apolar polymer forming weak interactions with every substance; quercetin dissolves into it from the halloysite surface only above a critical surface coverage. Stabilization experiments confirmed that strong adhesion prevents dissolution and results in limited stabilization efficiency. At larger adsorbed amounts better stability and extended effect were measured indicating dissolution and controlled release. Copyright © 2015 Elsevier Inc. All rights reserved.

Three dimensional model for particle saltation close to stream beds, including a detailed description of the particle interaction with turbulence and inter-particle collisions

KAUST Repository

Moreno, Pablo M.

2011-05-19

We present in this paper a new three-dimensional (3-D) model for bed-load sediment transport, based on a Lagrangian description. We analyze generalized sub-models for the velocities after collision and the representation of the bed-roughness. The free-flight sub-model includes the effect of several forces, such as buoyancy, drag, virtual mass, lift, Basset and Magnus, and also addresses the particle rotation. A recent methodology for saving computational time in the Basset force is also employed. The sub-models for the post-collision velocity and rotation are based on the conservation of linear and angular momentum during the collision with the bed. We develop a new 3-D representation for the bed roughness by using geometric considerations. In order to address the interaction of particles with the turbulent flow, we tracked the particles through a computed turbulent velocity field for a smooth flat plate. This velocity field was used as a surrogate of the 3-D turbulent conditions close to the bed in streams. We first checked that the basic turbulence statistics for this velocity field could be used to approximate those in an open-channel flow. We then analyzed the interaction of the sediment and the turbulence for a single and multiple particles. We compared numerical results with experimental data obtained by Niño and García (1998b). We show that model predictions are in good agreement with existing data, in the sand size range. © 2011 ASCE.

Three dimensional model for particle saltation close to stream beds, including a detailed description of the particle interaction with turbulence and inter-particle collisions

KAUST Repository

Moreno, Pablo M.; Bombardelli, Fabiá n A.; Gonzá lez, Andrea E.; Calo, Victor M.

2011-01-01

We present in this paper a new three-dimensional (3-D) model for bed-load sediment transport, based on a Lagrangian description. We analyze generalized sub-models for the velocities after collision and the representation of the bed-roughness. The free-flight sub-model includes the effect of several forces, such as buoyancy, drag, virtual mass, lift, Basset and Magnus, and also addresses the particle rotation. A recent methodology for saving computational time in the Basset force is also employed. The sub-models for the post-collision velocity and rotation are based on the conservation of linear and angular momentum during the collision with the bed. We develop a new 3-D representation for the bed roughness by using geometric considerations. In order to address the interaction of particles with the turbulent flow, we tracked the particles through a computed turbulent velocity field for a smooth flat plate. This velocity field was used as a surrogate of the 3-D turbulent conditions close to the bed in streams. We first checked that the basic turbulence statistics for this velocity field could be used to approximate those in an open-channel flow. We then analyzed the interaction of the sediment and the turbulence for a single and multiple particles. We compared numerical results with experimental data obtained by Niño and García (1998b). We show that model predictions are in good agreement with existing data, in the sand size range. © 2011 ASCE.

Utilization and control of ecological interactions in polymicrobial infections and community-based microbial cell factories.

Science.gov (United States)

Wigneswaran, Vinoth; Amador, Cristina Isabel; Jelsbak, Lotte; Sternberg, Claus; Jelsbak, Lars

2016-01-01

Microbial activities are most often shaped by interactions between co-existing microbes within mixed-species communities. Dissection of the molecular mechanisms of species interactions within communities is a central issue in microbial ecology, and our ability to engineer and control microbial communities depends, to a large extent, on our knowledge of these interactions. This review highlights the recent advances regarding molecular characterization of microbe-microbe interactions that modulate community structure, activity, and stability, and aims to illustrate how these findings have helped us reach an engineering-level understanding of microbial communities in relation to both human health and industrial biotechnology.

Interaction of the IAEA and the United States in controlling nuclear weapons proliferation

International Nuclear Information System (INIS)

Tape, G.F.

1977-01-01

The emphasis of this paper is on those aspects of the U. S.-IAEA interactions that pertain to the control and assurance of non-diversion of special nuclear materials. Some background information on the IAEA is given

Toehold-mediated internal control to probe the near-field interaction between the metallic nanoparticle and the fluorophore

Science.gov (United States)

Ang, Y. S.; Yung, L. Y. L.

2014-10-01

Metallic nanoparticles (MNPs) are known to alter the emission of vicinal fluorophores through the near-field interaction, leading to either fluorescence quenching or enhancement. Much ambiguity remains in the experimental outcome of such a near-field interaction, particularly for bulk colloidal solution. It is hypothesized that the strong far-field interference from the inner filter effect of the MNPs could mask the true near-field MNP-fluorophore interaction significantly. Thus, in this work, a reliable internal control capable of decoupling the near-field interaction from far-field interference is established by the use of the DNA toehold concept to mediate the in situ assembly and disassembly of the MNP-fluorophore conjugate. A model gold nanoparticle (AuNP)-Cy3 system is used to investigate our proposed toehold-mediated internal control system. The maximum fluorescence enhancement is obtained for large-sized AuNP (58 nm) separated from Cy3 at an intermediate distance of 6.8 nm, while fluorescence quenching is observed for smaller-sized AuNP (11 nm and 23 nm), which is in agreement with the theoretical values reported in the literature. This work shows that the toehold-mediated internal control design can serve as a central system for evaluating the near-field interaction of other MNP-fluorophore combinations and facilitate the rational design of specific MNP-fluorophore systems for various applications.Metallic nanoparticles (MNPs) are known to alter the emission of vicinal fluorophores through the near-field interaction, leading to either fluorescence quenching or enhancement. Much ambiguity remains in the experimental outcome of such a near-field interaction, particularly for bulk colloidal solution. It is hypothesized that the strong far-field interference from the inner filter effect of the MNPs could mask the true near-field MNP-fluorophore interaction significantly. Thus, in this work, a reliable internal control capable of decoupling the near

Tuning dipolar magnetic interactions by controlling individual silica coating of iron oxide nanoparticles

Science.gov (United States)

Rivas Rojas, P. C.; Tancredi, P.; Moscoso Londoño, O.; Knobel, M.; Socolovsky, L. M.

2018-04-01

Single and fixed size core, core-shell nanoparticles of iron oxides coated with a silica layer of tunable thickness were prepared by chemical routes, aiming to generate a frame of study of magnetic nanoparticles with controlled dipolar interactions. The batch of iron oxides nanoparticles of 4.5 nm radii, were employed as cores for all the coated samples. The latter was obtained via thermal decomposition of organic precursors, resulting on nanoparticles covered with an organic layer that was subsequently used to promote the ligand exchange in the inverse microemulsion process, employed to coat each nanoparticle with silica. The amount of precursor and times of reaction was varied to obtain different silica shell thicknesses, ranging from 0.5 nm to 19 nm. The formation of the desired structures was corroborated by TEM and SAXS measurements, the core single-phase spinel structure was confirmed by XRD, and superparamagnetic features with gradual change related to dipolar interaction effects were obtained by the study of the applied field and temperature dependence of the magnetization. To illustrate that dipolar interactions are consistently controlled, the main magnetic properties are presented and analyzed as a function of center to center minimum distance between the magnetic cores.

Controlled, Constrained, or Flexible? How Self-Management Goals Are Shaped By Patient-Provider Interactions.

Science.gov (United States)

Franklin, Marika; Lewis, Sophie; Willis, Karen; Rogers, Anne; Venville, Annie; Smith, Lorraine

2018-06-01

A person-centered approach to goal-setting, involving collaboration between patients and health professionals, is advocated in policy to support self-management. However, this is difficult to achieve in practice, reducing the potential effectiveness of self-management support. Drawing on observations of consultations between patients and health professionals, we examined how goal-setting is shaped in patient-provider interactions. Analysis revealed three distinct interactional styles. In controlled interactions, health professionals determine patients' goals based on biomedical reference points and present these goals as something patients should do. In constrained interactions, patients are invited to present goals, yet health professionals' language and questions orientate goals toward biomedical issues. In flexible interactions, patients and professionals both contribute to goal-setting, as health professionals use less directive language, create openings, and allow patients to decide on their goals. Findings suggest that interactional style of health professionals could be the focus of interventions when aiming to increase the effectiveness of goal-setting.

Virial theorem and Gibbs thermodynamic potential for Coulomb systems

International Nuclear Information System (INIS)

Bobrov, V. B.; Trigger, S. A.

2014-01-01

Using the grand canonical ensemble and the virial theorem, we show that the Gibbs thermodynamic potential of the non-relativistic system of charged particles is uniquely defined by single-particle Green functions of electrons and nuclei. This result is valid beyond the perturbation theory with respect to the interparticle interaction

Virial theorem and Gibbs thermodynamic potential for Coulomb systems

OpenAIRE

Bobrov, V. B.; Trigger, S. A.

2013-01-01

Using the grand canonical ensemble and the virial theorem, we show that the Gibbs thermodynamic potential of the non-relativistic system of charged particles is uniquely defined by single-particle Green functions of electrons and nuclei. This result is valid beyond the perturbation theory with respect to the interparticle interaction.

Motivational state controls the prediction error in Pavlovian appetitive-aversive interactions.

Science.gov (United States)

Laurent, Vincent; Balleine, Bernard W; Westbrook, R Frederick

2018-01-01

Contemporary theories of learning emphasize the role of a prediction error signal in driving learning, but the nature of this signal remains hotly debated. Here, we used Pavlovian conditioning in rats to investigate whether primary motivational and emotional states interact to control prediction error. We initially generated cues that positively or negatively predicted an appetitive food outcome. We then assessed how these cues modulated aversive conditioning when a novel cue was paired with a foot shock. We found that a positive predictor of food enhances, whereas a negative predictor of that same food impairs, aversive conditioning. Critically, we also showed that the enhancement produced by the positive predictor is removed by reducing the value of its associated food. In contrast, the impairment triggered by the negative predictor remains insensitive to devaluation of its associated food. These findings provide compelling evidence that the motivational value attributed to a predicted food outcome can directly control appetitive-aversive interactions and, therefore, that motivational processes can modulate emotional processes to generate the final error term on which subsequent learning is based. Copyright © 2017 Elsevier Inc. All rights reserved.

A free-piston Stirling engine/linear alternator controls and load interaction test facility

Science.gov (United States)

Rauch, Jeffrey S.; Kankam, M. David; Santiago, Walter; Madi, Frank J.

1992-01-01

A test facility at LeRC was assembled for evaluating free-piston Stirling engine/linear alternator control options, and interaction with various electrical loads. This facility is based on a 'SPIKE' engine/alternator. The engine/alternator, a multi-purpose load system, a digital computer based load and facility control, and a data acquisition system with both steady-periodic and transient capability are described. Preliminary steady-periodic results are included for several operating modes of a digital AC parasitic load control. Preliminary results on the transient response to switching a resistive AC user load are discussed.

Tiny changes in local order identify the cluster formation threshold in model fluids with competing interactions.

Science.gov (United States)

Bomont, Jean-Marc; Costa, Dino; Bretonnet, Jean-Louis

2017-06-14

We use Monte Carlo simulations to carry out a thorough analysis of structural correlations arising in a relatively dense fluid of rigid spherical particles with prototype competing interactions (short-range attractive and long-range repulsive two-Yukawa model). As the attraction strength increases, we show that the local density of the fluid displays a tiny reversal of trend within specific ranges of interparticle distances, whereupon it decreases first and increases afterwards, passing through a local minimum. Particles involved in this trend display, accordingly, distinct behaviours: for a sufficiently weak attraction, they seem to contribute to the long-wave oscillations typically heralding the formation of patterns in such fluids; for a stronger attraction, after the reversal of the local density has occurred, they form an outer shell of neighbours stabilizing the existing aggregation seeds. Following the increment of attraction, precisely in correspondence of the local density reversal, the local peak developed in the structure factor at small wavevectors markedly rises, signalling-in agreement with recent structural criteria-the onset of a clustered state. A detailed cluster analysis of microscopic configurations fully validates this picture.

The Interaction Between Control Rods as Estimated by Second-Order One-Group Perturbation Theory

Energy Technology Data Exchange (ETDEWEB)

Persson, Rolf

1966-10-15

The interaction effect between control rods is an important problem for the reactivity control of a reactor. The approach of second order one-group perturbation theory is shown to be attractive due to its simplicity. Formulas are derived for the fully inserted control rods in a bare reactor. For a single rod we introduce a correction parameter b, which with good approximation is proportional to the strength of the absorber. For two and more rods we introduce an interaction function g(r{sub ij}), which is assumed to depend only on the distance r{sub ij} between the rods. The theoretical expressions are correlated with the results of several experiments in R0, ZEBRA and the Aagesta reactor, as well as with more sophisticated calculations. The approximate formulas are found to give quite good agreement with exact values, but in the case of about 8 or more rods higher-order effects are likely to be important.

The Interaction Between Control Rods as Estimated by Second-Order One-Group Perturbation Theory

International Nuclear Information System (INIS)

Persson, Rolf

1966-10-01

The interaction effect between control rods is an important problem for the reactivity control of a reactor. The approach of second order one-group perturbation theory is shown to be attractive due to its simplicity. Formulas are derived for the fully inserted control rods in a bare reactor. For a single rod we introduce a correction parameter b, which with good approximation is proportional to the strength of the absorber. For two and more rods we introduce an interaction function g(r ij ), which is assumed to depend only on the distance r ij between the rods. The theoretical expressions are correlated with the results of several experiments in R0, ZEBRA and the Aagesta reactor, as well as with more sophisticated calculations. The approximate formulas are found to give quite good agreement with exact values, but in the case of about 8 or more rods higher-order effects are likely to be important

An exactly soluble Hartree problem in an external potential

International Nuclear Information System (INIS)

Gunn, J.C.; Gunn, J.M.F.

1987-09-01

The problem of N bosons interacting with each other via repulsive delta function interactions and with an external, attractive, delta function potential is solved within the Hartree approximation, exactly. It is found that if the interparticle interactions are above a certain value, there is no bound state. Thus the bound state does not just expand to compensate for the increase in the repulsive Hartree potential. Moreover as the interaction strength is increased to that value, the ground state wave function develops a pole at the position of the attractive potential. (author)

Experimental study on the control interaction force coefficient; Soju ryutairyoku kansho keisu ni kansuru jikkenteki kenkyu

Energy Technology Data Exchange (ETDEWEB)

Nakatake, K; Oda, K; Yoshitake, A; Fujita, K; Nakajima, A [Kyushu University, Fukuoka (Japan). Faculty of Engineering

1996-04-10

The interaction force induced to hull by steering is important for prediction of control performance of ships. The control interaction force coefficient dependent on the steering has been investigated through the rudder angle tests using three small model ships with a length of 2.5 m, i.e., mathematical type of ship, cargo type of ship, and tanker type of ship. The interaction forces acting on the hull, propeller, and rudder were determined by measuring the lateral force as well as the forward force of the hydrodynamic forces acting on the rudder. These forces were compared with the theoretically calculated values. Prior to the rudder angle tests, the self propulsion factor and the number of revolution of propeller were determined from the results of the open water tests, resistance tests, and self propulsion tests by the changing load method. The rudder angle tests were conducted under this number of revolution of propeller as a standard condition, and under those increasing and decreasing by 15%. Consequently, the interaction forces determined from the rudder angle tests agreed well with those determined from the other tests. When comparing the control hydrodynamic forces determined from the tests with those theoretically calculated, a similar trend was observed. Effectiveness of the theoretical model was confirmed. 4 refs., 14 figs., 3 tabs.

QUINT : A tool to detect qualitative treatment-subgroup interactions in randomized controlled trials

NARCIS (Netherlands)

Doove, L.L.; Van Deun, K.; Dusseldorp, E.; van Mechelen, I.

2016-01-01

Objective: The detection of subgroups involved in qualitative treatment–subgroup interactions (i.e., for one subgroup of clients treatment A outperforms treatment B, whereas for another the reverse holds true) is crucial for personalized health. In typical Randomized Controlled Trials (RCTs), the

Autonomy and control in dyads: effects on interaction quality and joint creative performance.

Science.gov (United States)

Weinstein, Netta; Hodgins, Holley S; Ryan, Richard M

2010-12-01

Two studies examined interaction quality and joint performance on two creative tasks in unacquainted dyads primed for autonomy or control orientations. It was hypothesized that autonomy-primed dyads would interact more constructively, experience more positive mood, and engage the task more readily, and as a result these dyads would perform better. To test this, Study 1 primed orientation and explored verbal creative performance on the Remote Associates Task (RAT). In Study 2, dyads were primed with autonomy and control orientation and videotaped during two joint creative tasks, one verbal (RAT) and one nonverbal (charades). Videotapes were coded for behavioral indicators of closeness and task engagement. Results showed that autonomy-primed dyads felt closer, were more emotionally and cognitively attuned, provided empathy and encouragement to partners, and performed more effectively. The effects of primed autonomy on creative performance were mediated by interpersonal quality, mood, and joint engagement.

Effect of cutoff radius, long range interaction and temperature controller on thermodynamic properties of fluids: Methanol as an example

Science.gov (United States)

Obeidat, Abdalla; Jaradat, Adnan; Hamdan, Bushra; Abu-Ghazleh, Hind

2018-04-01

The best spherical cutoff radius, long range interaction and temperature controller were determined using surface tension, density, and diffusion coefficients of van Leeuwen and Smit methanol. A quite good range of cutoff radii from 0.75 to 1.45 nm has been studied on Coulomb cut-off and particle mesh Ewald (PME) long range interaction to determine the best cutoff radius and best long range interaction as well for four sets of temperature: 200, 230, 270 and 300 K. To determine the best temperature controller, the cutoff radius of 1.25 nm was fixed using PME long range interaction on calculating the above properties at low temperature range: 200-300 K.

MINDS: A microcomputer interactive data system for 8086-based controllers

Science.gov (United States)

Soeder, J. F.

1985-01-01

A microcomputer interactive data system (MINDS) software package for the 8086 family of microcomputers is described. To enhance program understandability and ease of code maintenance, the software is written in PL/M-86, Intel Corporation's high-level system implementation language. The MINDS software is intended to run in residence with real-time digital control software to provide displays of steady-state and transient data. In addition, the MINDS package provides classic monitor capabilities along with extended provisions for debugging an executing control system. The software uses the CP/M-86 operating system developed by Digital Research, Inc., to provide program load capabilities along with a uniform file structure for data and table storage. Finally, a library of input and output subroutines to be used with consoles equipped with PL/M-86 and assembly language is described.

Structural mode significance using INCA. [Interactive Controls Analysis computer program

Science.gov (United States)

Bauer, Frank H.; Downing, John P.; Thorpe, Christopher J.

1990-01-01

Structural finite element models are often too large to be used in the design and analysis of control systems. Model reduction techniques must be applied to reduce the structural model to manageable size. In the past, engineers either performed the model order reduction by hand or used distinct computer programs to retrieve the data, to perform the significance analysis and to reduce the order of the model. To expedite this process, the latest version of INCA has been expanded to include an interactive graphical structural mode significance and model order reduction capability.

Reversible control of magnetic interactions by electric field in a single-phase material.

Science.gov (United States)

Ryan, P J; Kim, J-W; Birol, T; Thompson, P; Lee, J-H; Ke, X; Normile, P S; Karapetrova, E; Schiffer, P; Brown, S D; Fennie, C J; Schlom, D G

2013-01-01

Intrinsic magnetoelectric coupling describes the interaction between magnetic and electric polarization through an inherent microscopic mechanism in a single-phase material. This phenomenon has the potential to control the magnetic state of a material with an electric field, an enticing prospect for device engineering. Here, we demonstrate 'giant' magnetoelectric cross-field control in a tetravalent titanate film. In bulk form, EuTiO(3), is antiferromagnetic. However, both anti and ferromagnetic interactions coexist between different nearest europium neighbours. In thin epitaxial films, strain was used to alter the relative strength of the magnetic exchange constants. We not only show that moderate biaxial compression precipitates local magnetic competition, but also demonstrate that the application of an electric field at this strain condition switches the magnetic ground state. Using first-principles density functional theory, we resolve the underlying microscopic mechanism resulting in G-type magnetic order and illustrate how it is responsible for the 'giant' magnetoelectric effect.

Metal oxide/polyaniline nanocomposites

Indian Academy of Sciences (India)

Nanocomposites of iron oxide with conducting polymer in the form of powders of varying compositions have been studied to understand the effects of particle size, cluster size and magnetic inter-particle interactions. The sizes of the nanoparticles were estimated to be ∼ 10–20 nm from the X-ray diffraction (XRD) and the ...

Genetic susceptibility loci, environmental exposures, and Parkinson's disease: a case-control study of gene-environment interactions.

Science.gov (United States)

Chung, Sun Ju; Armasu, Sebastian M; Anderson, Kari J; Biernacka, Joanna M; Lesnick, Timothy G; Rider, David N; Cunningham, Julie M; Ahlskog, J Eric; Frigerio, Roberta; Maraganore, Demetrius M

2013-06-01

Prior studies causally linked mutations in SNCA, MAPT, and LRRK2 genes with familial Parkinsonism. Genome-wide association studies have demonstrated association of single nucleotide polymorphisms (SNPs) in those three genes with sporadic Parkinson's disease (PD) susceptibility worldwide. Here we investigated the interactions between SNPs in those three susceptibility genes and environmental exposures (pesticides application, tobacco smoking, coffee drinking, and alcohol drinking) also associated with PD susceptibility. Pairwise interactions between environmental exposures and 18 variants (16 SNPs and two variable number tandem repeats, or "VNTRs") in SNCA, MAPT and LRRK2, were investigated using data from 1098 PD cases from the upper Midwest, USA and 1098 matched controls. Environmental exposures were assessed using a validated telephone interview script. Five pairwise interactions had uncorrected P-values coffee drinking × MAPT H1/H2 haplotype or MAPT rs16940806, and alcohol drinking × MAPT rs2435211. None of these interactions remained significant after Bonferroni correction. Secondary analyses in strata defined by type of control (sibling or unrelated), sex, or age at onset of the case also did not identify significant interactions after Bonferroni correction. This study documented limited pairwise interactions between established genetic and environmental risk factors for PD; however, the associations were not significant after correction for multiple testing. Copyright © 2013 Elsevier Ltd. All rights reserved.

How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen.

Science.gov (United States)

Niinemets, Ülo; Sun, Zhihong

2015-02-01

Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 μmol mol(-1) or elevated [CO2] of 780 μmol mol(-1). The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Control dynamics of interaction quenched ultracold bosons in periodically driven lattices

Science.gov (United States)

Mistakidis, Simeon; Schmelcher, Peter; Group of Fundamental Processes in Quantum Physics Team

2016-05-01

The out-of-equilibrium dynamics of ultracold bosons following an interaction quench upon a periodically driven optical lattice is investigated. It is shown that an interaction quench triggers the inter-well tunneling dynamics, while for the intra-well dynamics breathing and cradle-like processes can be generated. In particular, the occurrence of a resonance between the cradle and tunneling modes is revealed. On the other hand, the employed periodic driving enforces the bosons in the mirror wells to oscillate out-of-phase and to exhibit a dipole mode, while in the central well the cloud experiences a breathing mode. The dynamical behaviour of the system is investigated with respect to the driving frequency revealing a resonant behaviour of the intra-well dynamics. To drive the system in a highly non-equilibrium state an interaction quench upon the driving is performed giving rise to admixtures of excitations in the outer wells, an enhanced breathing in the center and an amplification of the tunneling dynamics. As a result of the quench the system experiences multiple resonances between the inter- and intra-well dynamics at different quench amplitudes. Deutsche Forschungsgemeinschaft, SFB 925 ``Light induced dynamics and control of correlated quantum systems''.

Numerical and experimental analysis of the sedimentation of spherical colloidal suspensions under centrifugal force

Science.gov (United States)

Antonopoulou, Evangelia; Rohmann-Shaw, Connor F.; Sykes, Thomas C.; Cayre, Olivier J.; Hunter, Timothy N.; Jimack, Peter K.

2018-03-01

Understanding the sedimentation behaviour of colloidal suspensions is crucial in determining their stability. Since sedimentation rates are often very slow, centrifugation is used to expedite sedimentation experiments. The effect of centrifugal acceleration on sedimentation behaviour is not fully understood. Furthermore, in sedimentation models, interparticle interactions are usually omitted by using the hard-sphere assumption. This work proposes a one-dimensional model for sedimentation using an effective maximum volume fraction, with an extension for sedimentation under centrifugal force. A numerical implementation of the model using an adaptive finite difference solver is described. Experiments with silica suspensions are carried out using an analytical centrifuge. The model is shown to be a good fit with experimental data for 480 nm spherical silica, with the effects of centrifugation at 705 rpm studied. A conversion of data to Earth gravity conditions is proposed, which is shown to recover Earth gravity sedimentation rates well. This work suggests that the effective maximum volume fraction accurately captures interparticle interactions and provides insights into the effect of centrifugation on sedimentation.

Structure and dynamics of soft repulsive colloidal suspensions in the vicinity of the glass transition.

Science.gov (United States)

Crassous, Jérôme J; Casal-Dujat, Lucia; Medebach, Martin; Obiols-Rabasa, Marc; Vincent, Romaric; Reinhold, Frank; Boyko, Volodymyr; Willerich, Immanuel; Menzel, Andreas; Moitzi, Christian; Reck, Bernd; Schurtenberger, Peter

2013-08-20

We use a combination of different scattering techniques and rheology to highlight the link between structure and dynamics of dense aqueous suspensions of soft repulsive colloids in the vicinity of a glass transition. Three different latex formulations with an increasing amount of the hydrophilic component resulting in either purely electrostatically or electrosterically stabilized suspensions are investigated. From the analysis of the static structure factor measured by small-angle X-ray scattering, we derive an effective volume fraction that includes contributions from interparticle interactions. We further investigate the dynamics of the suspensions using 3D cross-correlation dynamic light scattering (3DDLS) and rheology. We analyze the data using an effective hard sphere model and in particular compare the linear viscoelasticity and flow behavior to the predictions of mode coupling theory, which accounts for a purely kinetic glass transition determined by the equilibrium structure factor. We demonstrate that seemingly very different colloidal systems exhibit the same generic behavior when the effects from interparticle interactions are incorporated using an effective volume fraction description.

Atomistic Structure of Mineral Nano-aggregates from Simulated Compaction and Dewatering.

Science.gov (United States)

Ho, Tuan Anh; Greathouse, Jeffery A; Wang, Yifeng; Criscenti, Louise J

2017-11-10

The porosity of clay aggregates is an important property governing chemical reactions and fluid flow in low-permeability geologic formations and clay-based engineered barrier systems. Pore spaces in clays include interlayer and interparticle pores. Under compaction and dewatering, the size and geometry of such pore spaces may vary significantly (sub-nanometer to microns) depending on ambient physical and chemical conditions. Here we report a molecular dynamics simulation method to construct a complex and realistic clay-like nanoparticle aggregate with interparticle pores and grain boundaries. The model structure is then used to investigate the effect of dewatering and water content on micro-porosity of the aggregates. The results suggest that slow dewatering would create more compact aggregates compared to fast dewatering. Furthermore, the amount of water present in the aggregates strongly affects the particle-particle interactions and hence the aggregate structure. Detailed analyses of particle-particle and water-particle interactions provide a molecular-scale view of porosity and texture development of the aggregates. The simulation method developed here may also aid in modeling the synthesis of nanostructured materials through self-assembly of nanoparticles.

Influence of PVP in magnetic properties of NiSn nanoparticles prepared by polyol method

Energy Technology Data Exchange (ETDEWEB)

Bobadilla, L.F., E-mail: lbobadilla@iciq.es [Departamento de Quimica Inorganica e Instituto de Ciencia de Materiales, Centro mixto Universidad de Sevilla-CSIC, Av. Americo Vespucio, 41092 Sevilla (Spain); Garcia, C. [Physics Department, Bogazici University, North Campus KB 331-O, Bebek/Istambul (Turkey); Delgado, J.J. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, E-11510 Puerto Real, Cadiz (Spain); Sanz, O. [Grupo de Ingenieria Quimica, Departamento de Quimica Aplicada, Facultad de Ciencias Quimicas, UPV/EHU, Paseo Manuel de Lardizabal, 3, 20018 San Sebastian (Spain); Romero-Sarria, F.; Centeno, M.A.; Odriozola, J.A. [Departamento de Quimica Inorganica e Instituto de Ciencia de Materiales, Centro mixto Universidad de Sevilla-CSIC, Av. Americo Vespucio, 41092 Sevilla (Spain)

2012-11-15

The influence of PVP on the magnetic properties of NiSn nanoparticles prepared by polyol method has been studied. NiSn nanoparticles exhibit superparamagnetic behavior although there is a ferromagnetic contribution due to particles agglomerated below the blocking temperature. The particle size is controlled by the addiction of PVP in varying amounts. The addition of PVP also favours the particles isolation, narrow the particle size distribution and decrease the interparticle interaction strength increasing the superparamagnetic contribution. - Highlights: Black-Right-Pointing-Pointer Ni{sub x}Sn{sub y} alloys nanoparticles have been prepared by polyol method. Black-Right-Pointing-Pointer NiSn nanoparticles exhibit superparamagnetic behavior. Black-Right-Pointing-Pointer The PVP addition favours the particles isolation.

Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

Science.gov (United States)

Luo, Wei; Pulsipher, Abigail; Dutta, Debjit; Lamb, Brian M.; Yousaf, Muhammad N.

2014-09-01

We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture spheroid tissue assembly in solution and co-culture tissue multilayer assembly on materials was demonstrated by an intercellular photo-oxime ligation that could be remotely cleaved and disassembled on demand. Spatial and temporal control of microtissue structures containing multiple cell types was demonstrated by the generation of patterned multilayers for controlling stem cell differentiation. Remote control of cell interactions via cell surface engineering that allows for real-time manipulation of tissue dynamics may provide tools with the scope to answer fundamental questions of cell communication and initiate new biotechnologies ranging from imaging probes to drug delivery vehicles to regenerative medicine, inexpensive bioreactor technology and tissue engineering therapies.

Efficacy of Parent-Child Interaction Therapy with Chinese ADHD Children: Randomized Controlled Trial

Science.gov (United States)

Leung, Cynthia; Tsang, Sandra; Ng, Gene S. H.; Choi, S. Y.

2017-01-01

Purpose: This study aimed to evaluate the efficacy of Parent-Child Interaction Therapy (PCIT) in Chinese children with attention-deficit/hyperactivity disorder (ADHD) or ADHD features. Methods: This study adopted a randomized controlled trial design without blinding. Participants were randomized into either the intervention group (n = 32) and…

Implications and control of fuel-cladding chemical interaction for LMFBR fuel pin design

International Nuclear Information System (INIS)

Roake, W.E.

1977-01-01

Fuel-cladding-chemical-interaction (FCCI) is typically incorporated into the design of an LMFBR fuel pin as a wastage allowance. Several interrelated factors are considered during the evolution of an LMFBR fuel pin design. Those which are indirectly affected by FCCI include: allowable pin power, fuel restructuring, fission gas migration and release from the fuel, fuel cracking, fuel swelling, in-reactor cladding creep, cladding swelling, and the cladding mechanical strain. Chemical activity of oxygen is the most readily controlled factor in FCCI. Two methods are being investigated: control of total oxygen inventory by limiting fuel O/M, and control of oxygen activity with buffer metals

Implications and control of fuel-cladding chemical interaction for LMFBR fuel pin design

Energy Technology Data Exchange (ETDEWEB)

Roake, W E [Westinghouse-Hanford Co., Richland, WA (United States)

1977-04-01

Fuel-cladding-chemical-interaction (FCCI) is typically incorporated into the design of an LMFBR fuel pin as a wastage allowance. Several interrelated factors are considered during the evolution of an LMFBR fuel pin design. Those which are indirectly affected by FCCI include: allowable pin power, fuel restructuring, fission gas migration and release from the fuel, fuel cracking, fuel swelling, in-reactor cladding creep, cladding swelling, and the cladding mechanical strain. Chemical activity of oxygen is the most readily controlled factor in FCCI. Two methods are being investigated: control of total oxygen inventory by limiting fuel O/M, and control of oxygen activity with buffer metals.

Instrumented Compliant Wrist with Proximity and Contact Sensing for Close Robot Interaction Control

Directory of Open Access Journals (Sweden)

Pascal Laferrière

2017-06-01

Full Text Available Compliance has been exploited in various forms in robotic systems to allow rigid mechanisms to come into contact with fragile objects, or with complex shapes that cannot be accurately modeled. Force feedback control has been the classical approach for providing compliance in robotic systems. However, by integrating other forms of instrumentation with compliance into a single device, it is possible to extend close monitoring of nearby objects before and after contact occurs. As a result, safer and smoother robot control can be achieved both while approaching and while touching surfaces. This paper presents the design and extensive experimental evaluation of a versatile, lightweight, and low-cost instrumented compliant wrist mechanism which can be mounted on any rigid robotic manipulator in order to introduce a layer of compliance while providing the controller with extra sensing signals during close interaction with an object’s surface. Arrays of embedded range sensors provide real-time measurements on the position and orientation of surfaces, either located in proximity or in contact with the robot’s end-effector, which permits close guidance of its operation. Calibration procedures are formulated to overcome inter-sensor variability and achieve the highest available resolution. A versatile solution is created by embedding all signal processing, while wireless transmission connects the device to any industrial robot’s controller to support path control. Experimental work demonstrates the device’s physical compliance as well as the stability and accuracy of the device outputs. Primary applications of the proposed instrumented compliant wrist include smooth surface following in manufacturing, inspection, and safe human-robot interaction.

Motor Control and Neural Plasticity through Interhemispheric Interactions

Directory of Open Access Journals (Sweden)

Naoyuki Takeuchi

2012-01-01

Full Text Available The corpus callosum, which is the largest white matter structure in the human brain, connects the 2 cerebral hemispheres. It plays a crucial role in maintaining the independent processing of the hemispheres and in integrating information between both hemispheres. The functional integrity of interhemispheric interactions can be tested electrophysiologically in humans by using transcranial magnetic stimulation, electroencephalography, and functional magnetic resonance imaging. As a brain structural imaging, diffusion tensor imaging has revealed the microstructural connectivity underlying interhemispheric interactions. Sex, age, and motor training in addition to the size of the corpus callosum influence interhemispheric interactions. Several neurological disorders change hemispheric asymmetry directly by impairing the corpus callosum. Moreover, stroke lesions and unilateral peripheral impairments such as amputation alter interhemispheric interactions indirectly. Noninvasive brain stimulation changes the interhemispheric interactions between both motor cortices. Recently, these brain stimulation techniques were applied in the clinical rehabilitation of patients with stroke by ameliorating the deteriorated modulation of interhemispheric interactions. Here, we review the interhemispheric interactions and mechanisms underlying the pathogenesis of these interactions and propose rehabilitative approaches for appropriate cortical reorganization.

Computer utility for interactive instrument control

International Nuclear Information System (INIS)

Day, P.

1975-08-01

A careful study of the ANL laboratory automation needs in 1967 led to the conclusion that a central computer could support all of the real-time needs of a diverse collection of research instruments. A suitable hardware configuration would require an operating system to provide effective protection, fast real-time response and efficient data transfer. An SDS Sigma 5 satisfied all hardware criteria, however it was necessary to write an original operating system; services include program generation, experiment control real-time analysis, interactive graphics and final analysis. The system is providing real-time support for 21 concurrently running experiments, including an automated neutron diffractometer, a pulsed NMR spectrometer and multi-particle detection systems. It guarantees the protection of each user's interests and dynamically assigns core memory, disk space and 9-track magnetic tape usage. Multiplexor hardware capability allows the transfer of data between a user's device and assigned core area at rates of 100,000 bytes/sec. Real-time histogram generation for a user can proceed at rates of 50,000 points/sec. The facility has been self-running (no computer operator) for five years with a mean time between failures of 10 []ays and an uptime of 157 hours/week. (auth)

Parental interaction patterns in children with attention deficit hyperactive disorder and control group

Directory of Open Access Journals (Sweden)

Mojgan Karahmadi

2007-07-01

Full Text Available

BACKGROUND: Parental communication patterns influence children's personality. This study investigated effects of parental interaction patterns on children with attention deficit hyperactive disorder (ADHD.
METHODS: There were 50 male children, 7-12 years old, selected in two groups. The first group included students with ADHD referred to psychiatry clinics in Isfahan-based on diagnostic scale of DSM-IV (25 subjects. The second group involved healthy boys selected by random cluster multistage sampling from primary schools in five districts of Isfahan (25 subjects from September 2005 to March 2005. Schaffer and Edgerton parental interaction questionnaire was filled for them.
RESULTS: Mean scores of parental interaction patterns in healthy children were all higher than those in ADHD children except for “aggression control” and “lack of aggressive attachment”.
CONCLUSIONS: The severity of ADHD signs has negative relationship with parental "admission" and parental "control" patterns. It also has positive relationship with “lack of aggressive/attachment” and “aggressive/control” patterns.
KEY WORDS: Parental interaction patterns, ADHD.

Clinical implications of antiretroviral drug interactions with warfarin: a case-control study.

Science.gov (United States)

Esterly, John S; Darin, Kristin M; Gerzenshtein, Lana; Othman, Fidah; Postelnick, Michael J; Scarsi, Kimberly K

2013-06-01

Warfarin, a frequently prescribed anticoagulant with a narrow therapeutic index, is susceptible to drug-drug interactions with antiretroviral therapy (ART). This study compared the warfarin maintenance dose (WMD) between patients receiving and not receiving ART and evaluated predictors of warfarin dosage among those on ART. This was a case-control (1:2) study. Cases were HIV-infected patients receiving warfarin and protease inhibitor (PI)- and/or non-nucleoside reverse transcriptase inhibitor (NNRTI)-based ART. Controls were randomly selected HIV-uninfected patients receiving warfarin. The WMD was compared between cases and controls and between cases on varying ART regimens. Bivariate comparisons were performed and a linear regression model was developed to identify predictors of WMD. We identified 18 case and 36 control patients eligible for inclusion. Cases were younger than controls (mean age: 45.8 versus 63.1 years, P African American (50.0% versus 22.2%, P=0.04). ART was classified as PI-based (n=9), NNRTI-based (n=7) and PI + NNRTI-based (n=2). The WMD (mean ± SD) differed between cases and controls (8.6  ±  3.4 mg versus 5.1 ± 1.5 mg, P ART regimens (PI: 8.8  ±  4.5 mg; NNRTI: 8.6   ± 1.8 mg; PI + NNRTI: 7.3  ±  3.3 mg; P = 0.86). Race and ritonavir dose were independent predictors of WMD, predicting an increase of 3.9 mg (95% CI: 0.88-6.98, P = 0.02) if a patient was African American or 3.7 mg (95% CI: 0.53-6.89, P = 0.03) if the total daily ritonavir dose was 200 mg. The required WMD was significantly higher in patients receiving ART. Prompt dose titration to achieve a higher WMD with vigilant monitoring may be required due to these drug-drug interactions.

Controlling single-molecule junction conductance by molecular interactions

Science.gov (United States)

Kitaguchi, Y.; Habuka, S.; Okuyama, H.; Hatta, S.; Aruga, T.; Frederiksen, T.; Paulsson, M.; Ueba, H.

2015-01-01

For the rational design of single-molecular electronic devices, it is essential to understand environmental effects on the electronic properties of a working molecule. Here we investigate the impact of molecular interactions on the single-molecule conductance by accurately positioning individual molecules on the electrode. To achieve reproducible and precise conductivity measurements, we utilize relatively weak π-bonding between a phenoxy molecule and a STM-tip to form and cleave one contact to the molecule. The anchoring to the other electrode is kept stable using a chalcogen atom with strong bonding to a Cu(110) substrate. These non-destructive measurements permit us to investigate the variation in single-molecule conductance under different but controlled environmental conditions. Combined with density functional theory calculations, we clarify the role of the electrostatic field in the environmental effect that influences the molecular level alignment. PMID:26135251

Análise da relação entre distância de separação entre partículas (IPS e viscosidade de suspensões Analisys of the relation between inter-particle spacing (IPS and suspension’s viscosity

Directory of Open Access Journals (Sweden)

F. S. Ortega

1999-05-01

Full Text Available O crescente interesse em ampliar a previsibilidade dos fenômenos que ocorrem durante a fabricação de materiais cerâmicos por processos coloidais, como a variação da viscosidade de suspensões, tem estimulado a implantação de vários modelos teóricos com tal finalidade. Considerando a concentração de sólidos na suspensão e a distribuição de tamanho de partícula do pó, a hipótese de que uma maior distância de separação entre partículas (IPS favorece uma menor viscosidade tem sido empregada com relativo sucesso, principalmente em cerâmicas tradicionais. No entanto, uma análise criteriosa de tal conceito revela pontos controversos. Neste trabalho, tais pontos são discutidos, bem como as condições em que os conceitos físicos desta abordagem são válidos para prever a viscosidade de suspensões cerâmicas. Complementam-se as análises com a caracterização reológica de suspensões de alumina. Os resultados comprovam que o conceito de distância de separação entre partículas pode ser empregado somente em condições específicas para que possua uma relação satisfatória com a viscosidade.The great importance of widening the prediction of phenomena occurring during ceramics fabrication processes has motivated the adoption of many theoretical models for that. Regarding suspension’s density and particle size distribution, the concept that a higher inter-particle spacing (IPS favours a lower viscosity has obtained some success, specially in traditional ceramic’s industries. However, a strict analysis of such idea indicates some conflicting points. In this paper, such points are discussed, as well as the conditions which validate the concepts of this approach. Rheological characterisation of alumina suspensions complements the analysis. The results show that the inter-particle spacing may be related to suspension’s viscosity only under some very specific conditions.

Different modes of APC/C activation control growth and neuron-glia interaction in the developing Drosophila eye.

Science.gov (United States)

Neuert, Helen; Yuva-Aydemir, Yeliz; Silies, Marion; Klämbt, Christian

2017-12-15

The development of the nervous system requires tight control of cell division, fate specification and migration. The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase that affects different steps of cell cycle progression, as well as having postmitotic functions in nervous system development. It can therefore link different developmental stages in one tissue. The two adaptor proteins, Fizzy/Cdc20 and Fizzy-related/Cdh1, confer APC/C substrate specificity. Here, we show that two distinct modes of APC/C function act during Drosophila eye development. Fizzy/Cdc20 controls the early growth of the eye disc anlage and the concomitant entry of glial cells onto the disc. In contrast, fzr/cdh1 acts during neuronal patterning and photoreceptor axon growth, and subsequently affects neuron-glia interaction. To further address the postmitotic role of Fzr/Cdh1 in controlling neuron-glia interaction, we identified a series of novel APC/C candidate substrates. Four of our candidate genes are required for fzr/cdh1 -dependent neuron-glia interaction, including the dynein light chain Dlc90F Taken together, our data show how different modes of APC/C activation can couple early growth and neuron-glia interaction during eye disc development. © 2017. Published by The Company of Biologists Ltd.

The calculation of electron density of the non-ideal argon plasma

International Nuclear Information System (INIS)

Jiang Ming; Cheng Xinlu; Yang Xiangdong

2004-01-01

By the screened hydrogenic model, the paper calculates the electron densities of shock-generated argon plasma with temperature T∼2.0 eV and density of plasma ρ∼0.01 g/cm 3 -0.49 g/cm 3 , and studies the influence on electron density caused by interparticle interaction at the different temperature and density of plasma. (author)

Interaction of attentional and motor control processes in handwriting.

Science.gov (United States)

Brown, T L; Donnenwirth, E E

1990-01-01

The interaction between attentional capacity, motor control processes, and strategic adaptations to changing task demands was investigated in handwriting, a continuous (rather than discrete) skilled performance. Twenty-four subjects completed 12 two-minute handwriting samples under instructions stressing speeded handwriting, normal handwriting, or highly legible handwriting. For half of the writing samples, a concurrent auditory monitoring task was imposed. Subjects copied either familiar (English) or unfamiliar (Latin) passages. Writing speed, legibility ratings, errors in writing and in the secondary auditory task, and a derived measure of the average number of characters held in short-term memory during each sample ("planning unit size") were the dependent variables. The results indicated that the ability to adapt to instructions stressing speed or legibility was substantially constrained by the concurrent listening task and by text familiarity. Interactions between instructions, task concurrence, and text familiarity in the legibility ratings, combined with further analyses of planning unit size, indicated that information throughput from temporary storage mechanisms to motor processes mediated the loss of flexibility effect. Overall, the results suggest that strategic adaptations of a skilled performance to changing task circumstances are sensitive to concurrent attentional demands and that departures from "normal" or "modal" performance require attention.

Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells

Science.gov (United States)

Alkandry, Hicham

Future missions to Mars, including sample-return and human-exploration missions, may require alternative entry, descent, and landing technologies in order to perform pinpoint landing of heavy vehicles. Two such alternatives are propulsive deceleration (PD) and reaction control systems (RCS). PD can slow the vehicle during Mars atmospheric descent by directing thrusters into the incoming freestream. RCS can provide vehicle control and steering by inducing moments using thrusters on the hack of the entry capsule. The use of these PD and RCS jets, however, involves complex flow interactions that are still not well understood. The fluid interactions induced by PD and RCS jets for Mars-entry vehicles in hypersonic freestream conditions are investigated using computational fluid dynamics (CFD). The effects of central and peripheral PD configurations using both sonic and supersonic jets at various thrust conditions are examined in this dissertation. The RCS jet is directed either parallel or transverse to the freestream flow at different thrust conditions in order to examine the effects of the thruster orientation with respect to the center of gravity of the aeroshell. The physical accuracy of the computational method is also assessed by comparing the numerical results with available experimental data. The central PD configuration decreases the drag force acting on the entry capsule due to a shielding effect that prevents mass and momentum in the hypersonic freestream from reaching the aeroshell. The peripheral PD configuration also decreases the drag force by obstructing the flow around the aeroshell and creating low surface pressure regions downstream of the PD nozzles. The Mach number of the PD jets, however, does not have a significant effect on the induced fluid interactions. The reaction control system also alters the flowfield, surface, and aerodynamic properties of the aeroshell, while the jet orientation can have a significant effect on the control effectiveness

Control of a shock wave-boundary layer interaction using localized arc filament plasma actuators

Science.gov (United States)

Webb, Nathan Joseph

Supersonic flight is currently possible, but expensive. Inexpensive supersonic travel will require increased efficiency of high-speed air entrainment, an integral part of air-breathing propulsion systems. Although mixed compression inlet geometry can significantly improve entrainment efficiency, numerous Shock Wave-Boundary Layer Interactions (SWBLIs) are generated in this configuration. The boundary layer must therefore develop through multiple regions of adverse pressure gradient, causing it to thicken, and, in severe cases, separate. The associated increase in unsteadiness can have adverse effects on downstream engine hardware. The most severe consequence of these interactions is the increased aerodynamic blockage generated by the thickened boundary layer. If the increase is sufficient, it can choke the flow, causing inlet unstart, and resulting in a loss of thrust and high transient forces on the engine, airframe, and aircraft occupants. The potentially severe consequences associated with SWBLIs require flow control to ensure proper operation. Traditionally, boundary layer bleed has been used to control the interaction. Although this method is effective, it has inherent efficiency penalties. Localized Arc Filament Plasma Actuators (LAFPAs) are designed to generate perturbations for flow control. Natural flow instabilities act to amplify certain perturbations, allowing the LAFPAs to control the flow with minimal power input. LAFPAs also have the flexibility to maintain control over a variety of operating conditions. This work seeks to examine the effectiveness of LAFPAs as a separation control method for an oblique, impinging SWBLI. The low frequency unsteadiness in the reflected shock was thought to be the natural manifestation of a Kelvin-Helmholtz instability in the shear layer above the separation region. The LAFPAs were therefore placed upstream of the interaction to allow their perturbations to convect to the receptivity region (near the shear layer origin

Ecosystem development in roadside grasslands: biotic control, plant–soil interactions and dispersal limitations

Science.gov (United States)

García-Palacios, Pablo; Bowker, Matthew A.; Maestre, Fernando T.; Soliveres, Santiago; Valladares, Fernando; Papadopoulos, Jorge; Escudero, Adrián

2015-01-01

Roadside grasslands undergoing secondary succession are abundant, and represent ecologically meaningful examples of novel, human-created ecosystems. Interactions between plant and soil communities (hereafter plant–soil interactions) are of major importance in understanding the role of biotic control in ecosystem functioning, but little is known about these links in the context of ecosystem restoration and succession. The assessment of the key biotic communities and interactions driving ecosystem development will help practitioners to better allocate the limited resources devoted to roadside grassland restoration. We surveyed roadside grasslands from three successional stages (0–2, 7–9 and > 20 years) in two Mediterranean regions of Spain. Structural equation modeling was used to evaluate how interactions between plants, biological soil crusts [BSCs], and soil microbial functional diversity [soil microorganisms] affect indicators of ecosystem development and restoration: plant similarity to the reference ecosystem, erosion control and soil C storage and N accumulation. Changes in plant community composition along the successional gradient exerted the strongest influence on these indicators. High BSC cover was associated with high soil stability, and high soil microbial functional diversity from late-successional stages was associated with high soil fertility. Contrary to our expectations, the indirect effects of plants, mediated by either BSCs or soil microorganisms, were very weak in both regions, suggesting a minor role for plant–soil interactions upon ecosystem development indicators over long periods. Our results suggest that natural vegetation dynamics effectively improved ecosystem development within a time frame of 20 years in the grasslands evaluated. They also indicate that this time could be shortened if management actions focus on: 1) maintain well-conserved natural areas close to roadsides to enhance plant compositional changes towards late

Ecosystem development in roadside grasslands: Biotic control, plant-soil interactions, and dispersal limitations

Science.gov (United States)

Garcia-Palacios, P.; Bowker, M.A.; Maestre, F.T.; Soliveres, S.; Valladares, F.; Papadopoulos, J.; Escudero, A.

2011-01-01

Roadside grasslands undergoing secondary succession are abundant, and represent ecologically meaningful examples of novel, human-created ecosystems. Interactions between plant and soil communities (hereafter plant-soil interactions) are of major importance in understanding the role of biotic control in ecosystem functioning, but little is known about these links in the context of ecosystem restoration and succession. The assessment of the key biotic communities and interactions driving ecosystem development will help practitioners to better allocate the limited resources devoted to roadside grassland restoration. We surveyed roadside grasslands from three successional stages (0-2, 7-9, and > 20 years) in two Mediterranean regions of Spain. Structural equation modeling was used to evaluate how interactions between plants, biological soil crusts (BSCs), and soil microbial functional diversity (soil microorganisms) affect indicators of ecosystem development and restoration: plant similarity to the reference ecosystem, erosion control, and soil C storage and N accumulation. Changes in plant community composition along the successional gradient exerted the strongest influence on these indicators. High BSC cover was associated with high soil stability, and high soil microbial functional diversity from late-successional stages was associated with high soil fertility. Contrary to our expectations, the indirect effects of plants, mediated by either BSCs or soil microorganisms, were very weak in both regions, suggesting a minor role for plant-soil interactions upon ecosystem development indicators over long periods. Our results suggest that natural vegetation dynamics effectively improved ecosystem development within a time frame of 20 years in the grasslands evaluated. They also indicate that this time could be shortened if management actions focus on: (1) maintaining wellconserved natural areas close to roadsides to enhance plant compositional changes towards late

Petri Nets Based Modelling of Control Flow for Memory-Aid Interactive Programs in Telemedicine

CERN Document Server

Khoromskaia, V K

2004-01-01

Petri Nets (PN) based modelling of the control flow for the interactive memory assistance programs designed for personal pocket computers and having special requirements for robustness is considered. The proposed concept allows one to elaborate the programs which can give users a variety of possibilities for a day-time planning in the presence of environmental and time restrictions. First, a PN model for a known simple algorithm is constructed and analyzed using the corresponding state equations and incidence matrix. Then a PN graph for a complicated algorithm with overlapping actions and choice possibilities is designed, supplemented by an example of its analysis. Dynamic behaviour of this graph is tested by tracing of all possible paths of the flow of control using the PN simulator. It is shown that PN based modelling provides reliably predictable performance of interactive algorithms with branched structures and concurrency requirements.

In-reactor performance of methods to control fuel-cladding chemical interaction

International Nuclear Information System (INIS)

Weber, E.T.; Gibby, R.L.; Wilson, C.N.; Lawrence, L.A.; Adamson, M.G.

1979-01-01

Inner surface corrosion of austenitic stainless steel cladding by oxygen and reactive fission product elements requires a 50 μm wastage allowance in current FBR reference oxide fuel pin design. Elimination or reduction of this wastage allowance could result in better reactor efficiency and economics through improvements in fuel pin performance and reliability. Reduction in cladding thickness and replacement of equivalent volume with fuel result in improved breeding capability. Of the factors affecting fuel-cladding chemical interaction (FCCI), oxygen activity within the fuel pin can be most readily controlled and/or manipulated without degrading fuel pin performance or significantly increasing fuel fabrication costs. There are two major approaches to control oxygen activity within an oxide fuel pin: (1) control of total oxygen inventory and chemical activity (Δ anti GO 2 ) by use of low oxygen-to-metal ratio (O/M) fuel; and (2) incorporation of a material within the fuel pin to provide in-situ control of oxygen activity (Δ anti GO 2 ) and fixation of excess oxygen prior to, or in preference to reaction with the cladding. The paper describes irradiation tests which were conducted in EBR-II and GETR incorporating oxygen buffer/getter materials and very low O/M fuel to control oxygen activity in sealed fuel pins

Molecular dynamics study of the structure and interparticle interactions of polyethylene glycol-conjugated PAMAM dendrimers.

Science.gov (United States)

Lee, Hwankyu; Larson, Ronald G

2009-10-08

We performed molecular dynamics (MD) simulations of one or two copies of polyethylene glycol of molecular weight 550 (PEG550) and 5000 (PEG5000) daltons, conjugated to generation 3 (G3) to 5 (G5) polyamidoamine (PAMAM) dendrimers with explicit water using a coarse-grained model. We found the radii of gyration of these dendrimer-PEG molecules to be close to those measured in experiments by Hedden and Bauer (Hedden , R. C. ; Bauer , B. J. Macromolecules 2003 , 36 , 1829.). Densely grafted PEG ligands (>50% of the dendrimer surface) extend like brushes, with layer thickness in agreement with theory for starlike polymers. Two dendrimer-PEG complexes in the box drift away from each other, indicating that no aggregation is induced by either short or long PEG chains, conflicting with a recent view that the cytotoxicity of some PEGylated particles might be due to particle aggregation for long PEG lengths.

Understanding particle size and distance driven competition of interparticle interactions and effective single-particle anisotropy

Czech Academy of Sciences Publication Activity Database

Pacáková, Barbara; Mantlíková, Alice; Nižňanský, D.; Kubíčková, Simona; Vejpravová, Jana

2016-01-01

Roč. 28, č. 20 (2016), 1-11, č. článku 206004. ISSN 0953-8984 R&D Projects: GA ČR(CZ) GA15-01953S Institutional support: RVO:68378271 Keywords : magnetic nanoparticles * single-particle anisotropy * dipolar energy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.649, year: 2016

Rice Starch Particle Interactions at Air/Aqueous Interfaces—Effect of Particle Hydrophobicity and Solution Ionic Strength

Science.gov (United States)

McNamee, Cathy E.; Sato, Yu; Wiege, Berthold; Furikado, Ippei; Marefati, Ali; Nylander, Tommy; Kappl, Michael; Rayner, Marilyn

2018-01-01

Starch particles modified by esterification with dicarboxylic acids to give octenyl succinic anhydride (OSA) starch is an approved food additive that can be used to stabilize oil in water emulsions used in foods and drinks. However, the effects of the OSA modification of the starch particle on the interfacial interactions are not fully understood. Here, we directly measured the packing of films of rice starch granules, i.e., the natural particle found inside the plant, at air/aqueous interfaces, and the interaction forces in that system as a function of the particle hydrophobicity and ionic strength, in order to gain insight on how starch particles can stabilize emulsions. This was achieved by using a combined Langmuir trough and optical microscope system, and the Monolayer Interaction Particle Apparatus. Native rice starch particles were seen to form large aggregates at air/water interfaces, causing films with large voids to be formed at the interface. The OSA modification of the rice starches particles decreased this aggregation. Increasing the degree of modification improved the particle packing within the film of particles at the air/water interface, due to the introduction of inter-particle electrostatic interactions within the film. The introduction of salt to the water phase caused the particles to aggregate and form holes within the film, due to the screening of the charged groups on the starch particles by the salt. The presence of these holes in the film decreased the stiffness of the films. The effect of the OSA modification was concluded to decrease the aggregation of the particles at an air/water interface. The presence of salts, however, caused the particles to aggregate, thereby reducing the strength of the interfacial film. PMID:29868551

Mealtime family interactions in home environments of children with loss of control eating.

Science.gov (United States)

Czaja, Julia; Hartmann, Andrea Sabrina; Rief, Winfried; Hilbert, Anja

2011-06-01

Experimental and self-report studies have shown that parents have a strong influence on their normal or overweight children's eating behavior, i.e. through parental feeding behavior or communication. Studies in children with loss of control (LOC) eating that have investigated this relationship are scarce, and ecologically valid observational studies are missing. This study examined family functioning at mealtimes in home environments in 43 families of a child with LOC eating and 31 families of a child without LOC eating; the children were 8-13 years old. Familial interactions, child eating behavior, and parental mealtime behavior were assessed using the Mealtime Family Interaction Coding System, observation of bite speed of the child, and self-report questionnaires. Less healthy patterns of communication (U=201.53, pchild with LOC eating compared to those without LOC eating. Children with LOC eating (M=4.73, SD=1.88) ate faster than controls (M=3.71, SD=1.19; pchild's eating behavior. Parent-child communication training should be tested as an intervention for children with LOC episodes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Contributions to the 7th International Conference on plasma surface interactions in controlled fusion devices

International Nuclear Information System (INIS)

1986-01-01

The report contains three papers presented in the 7th International Conference on plasma surface interactions in controlled fusion devices held in Princeton (USA) 5-9 May 1986, all referred to the FT Tokamak

Musical friends and foes: The social cognition of affiliation and control in improvised interactions.

Science.gov (United States)

Aucouturier, Jean-Julien; Canonne, Clément

2017-04-01

A recently emerging view in music cognition holds that music is not only social and participatory in its production, but also in its perception, i.e. that music is in fact perceived as the sonic trace of social relations between a group of real or virtual agents. While this view appears compatible with a number of intriguing music cognitive phenomena, such as the links between beat entrainment and prosocial behaviour or between strong musical emotions and empathy, direct evidence is lacking that listeners are at all able to use the acoustic features of a musical interaction to infer the affiliatory or controlling nature of an underlying social intention. We created a novel experimental situation in which we asked expert music improvisers to communicate 5 types of non-musical social intentions, such as being domineering, disdainful or conciliatory, to one another solely using musical interaction. Using a combination of decoding studies, computational and psychoacoustical analyses, we show that both musically-trained and non musically-trained listeners can recognize relational intentions encoded in music, and that this social cognitive ability relies, to a sizeable extent, on the information processing of acoustic cues of temporal and harmonic coordination that are not present in any one of the musicians' channels, but emerge from the dynamics of their interaction. By manipulating these cues in two-channel audio recordings and testing their impact on the social judgements of non-musician observers, we finally establish a causal relationship between the affiliation dimension of social behaviour and musical harmonic coordination on the one hand, and between the control dimension and musical temporal coordination on the other hand. These results provide novel mechanistic insights not only into the social cognition of musical interactions, but also into that of non-verbal interactions as a whole. Copyright © 2017. Published by Elsevier B.V.

Controlled initiation and quantitative visualization of cell interaction dynamics - a novel hybrid microscopy method -

NARCIS (Netherlands)

Snijder-van As, M.I.

2010-01-01

This thesis describes the development, validation, and application of a hybrid microscopy technique to study cell-substrate and cell-cell interactions in a controlled and quantitative manner. We studied the spatial and temporal dynamics of the selected membrane molecules CD6 and the activated

Ground-state and dynamical properties of two-dimensional dipolar Fermi liquids

International Nuclear Information System (INIS)

Abedinpour, Saeed H.; Asgari, Reza; Tanatar, B.; Polini, Marco

2014-01-01

We study the ground-state properties of a two-dimensional spin-polarized fluid of dipolar fermions within the Euler–Lagrange Fermi-hypernetted-chain approximation. Our method is based on the solution of a scattering Schrödinger equation for the “pair amplitude” √(g(r)), where g(r) is the pair distribution function. A key ingredient in our theory is the effective pair potential, which includes a bosonic term from Jastrow–Feenberg correlations and a fermionic contribution from kinetic energy and exchange, which is tailored to reproduce the Hartree–Fock limit at weak coupling. Very good agreement with recent results based on quantum Monte Carlo simulations is achieved over a wide range of coupling constants up to the liquid-to-crystal quantum phase transition. Using the fluctuation–dissipation theorem and a static approximation for the effective inter-particle interactions, we calculate the dynamical density–density response function, and furthermore demonstrate that an undamped zero-sound mode exists for any value of the interaction strength, down to infinitesimally weak couplings. -- Highlights: •We have studied the ground state properties of a strongly correlated two-dimensional fluid of dipolar fermions. •We have calculated the effective inter-particle interaction and the dynamical density–density response function. •We have shown that an undamped zero sound mode exists at any value of the interaction strength

Improvement of confinement characteristics of tokamak plasma by controlling plasma-wall interactions

International Nuclear Information System (INIS)

Sengoku, Seio

1985-08-01

Relation between plasma-wall interactions and confinement characteristics of a tokamak plasma with respect to both impurity and fuel particle controls is discussed. Following results are obtained from impurity control studies: (1) Ion sputtering is the dominant mechanism of impurity release in a steady state tokamak discharge. (2) By applying carbon coating on entire first wall of DIVA tokamak, dominant radiative region is concentrated more in boundary plasma resulting a hot peripheral plasma with cold boundary plasma. (3) A physical model of divertor functions about impurity control is empilically obtained. By a computer simulation based on above model with respect to divertor functions for JT-60 tokamak, it is found that the allowable electron temperature of the divertor plasma is not restricted by a condition that the impurity release due to ion sputtering does not increase continuously. (4) Dense and cold divertor plasma accompanied with strong remote radiative cooling was diagnosed along the magnetic field line in the simple poloidal divertor of DOUBLET III tokamak. Strong particle recycling region is found to be localized near the divertor plate. by and from particle control studies: (1) The INTOR scaling on energy confinement time is applicable to high density region when a core plasma is fueled directly by solid deuterium pellet injection in DOUBLET III tokamak. (2) As remarkably demonstrated by direct fueling with pellet injection, energy confinement characteristics can be improved at high density range by decreasing particle deposition at peripheral plasma in order to reduce plasma-wall interaction. (3) If the particle deposition at boundary layer is necessarily reduced, the electron temperature at the boundary or divertor region increases due to decrease of the particle recycling and the electron density there. (J.P.N.)

Self-organized magnetic particles to tune the mechanical behavior of a granular system

Science.gov (United States)

Cox, Meredith; Wang, Dong; Barés, Jonathan; Behringer, Robert P.

2016-09-01

Above a certain density a granular material jams. This property can be controlled by either tuning a global property, such as the packing fraction or by applying shear strain, or at the micro-scale by tuning grain shape, inter-particle friction or externally controlled organization. Here, we introduce a novel way to change a local granular property by adding a weak anisotropic magnetic interaction between particles. We measure the evolution of the pressure, P, and coordination number, Z, for a packing of 2D photo-elastic disks, subject to uniaxial compression. A fraction R m of the particles have embedded cuboidal magnets. The strength of the magnetic interactions between particles is too weak to have a strong direct effect on P or Z when the system is jammed. However, the magnetic interactions play an important role in the evolution of latent force networks when systems containing a large enough fraction of the particles with magnets are driven through unjammed to jammed states. In this case, a statistically stable network of magnetic chains self-organizes before jamming and overlaps with force chains once jamming occurs, strengthening the granular medium. This property opens a novel way to control mechanical properties of granular materials.

Interaction between demand-control and social support in the occurrence of common mental disorders

Directory of Open Access Journals (Sweden)

Amália Ivine Santana Mattos

Full Text Available ABSTRACT OBJECTIVE To analyze the interaction between the psychosocial aspects of work and the occurrence of common mental disorders among health workers. METHODS This is a cross-sectional study conducted with a representative sample of workers of the primary health care of five municipalities of the State of Bahia, Brazil, in 2012. The variable of outcome were the common mental disorders evaluated by the SRQ-20, and the variables of exposure were high demand (high psychological demand and low control over the work and low social support in the workplace. Interaction was checked by the deviation of the additivity of the effects for the factors studied from the calculation of excess risk from interaction, proportion of cases attributed to interaction, and the synergy index. RESULTS The global prevalence of common mental disorders was 21%. The group of combined exposure has shown higher magnitude (high demand and low social support, reaching 28% when compared to the 17% in the situation of no exposure (low demand and high social support. CONCLUSIONS The results strengthen the hypothesis of interaction between the factors investigated, directing to the synergy of the effects.

Team interaction skills evaluation criteria for nuclear power plant control room operators

International Nuclear Information System (INIS)

Montgomery, J.C.; Hauth, J.T.

1991-01-01

Team interaction skills are an essential aspect of safe nuclear power plant control room operations. Previous research has shown that, when a group works together, rather than as individuals, more effective operations are possible. However, little research has addressed how such team interaction skills can be measured. In this study rating scales were developed specifically for such a measurement purpose. Dimensions of team skill performance were identified from previous research and experience in the area, incorporating the input of Pacific Northwest Laboratory (PNL) contract operator licensing examiners. Rating scales were developed on the basis of these dimensions, incorporating a modified Behaviorally Anchored Rating Scale (BARS) as well as Behavioral Frequency formats. After a pilot-testing/revision process, rating data were collected using 11 control room crews responding to simulator scenarios at a boiling water and a pressurized water reactor. Statistical analyses of the resulting data revealed moderate inter-rater reliability using the Behavioral Frequency scales, relatively low inter-rater reliability using the BARS, and moderate support for convergent and discriminant validity of the scales. It was concluded that the scales show promise psychometrically and in terms of user acceptability, but that additional scale revision is needed before field implementation. Recommendations for scale revision and directions for future research were presented

A nested case-control approach to interactions between radiation dose and other factors as causes of cancer

Energy Technology Data Exchange (ETDEWEB)

Land, Charles E [Department of Epidemiology, Radiation Epidemiology Branch, US National Cancer Institute, Bethesda, MD (United States)

1992-04-01

Often a nested case-control study is the most practicable approach to estimating the interaction of two cancer risk factors in a large cohort. If one of the factors has already been evaluated for the entire cohort, however, more information is already available about its relationship to risk than could be obtained from a nested study. A modified case-control approach is proposed, in which information about the second, unknown factor is sought for cases and controls matched on the first factor. The approach requires, for interaction models other than the multiplicative, a nonstandard analytical approach incorporating cohort-based information about the first factor. The problem is discussed in the context of breast cancer risk in a defined cohort of female Japanese atomic bomb survivors, in relation to radiation dose and reproductive history. (author)

The role of plant-microbiome interactions in weed establishment and control.

Science.gov (United States)

Trognitz, Friederike; Hackl, Evelyn; Widhalm, Siegrid; Sessitsch, Angela

2016-10-01

The soil microbiome plays an important role in the establishment of weeds and invasive plants. They associate with microorganisms supporting their growth and health. Weed management strategies, like tillage and herbicide treatments, to control weeds generally alter soil structure going alongside with changes in the microbial community. Once a weed population establishes in the field, the plants build up a close relationship with the available microorganisms. Seeds or vegetative organs overwinter in soil and select early in the season their own microbiome before crop plants start to vegetate. Weed and crop plants compete for light, nutrition and water, but may differently interact with soil microorganisms. The development of new sequencing technologies for analyzing soil microbiomes has opened up the possibility for in depth analysis of the interaction between 'undesired' plants and crop plants under different management systems. These findings will help us to understand the functions of microorganisms involved in crop productivity and plant health, weed establishment and weed prevention. Exploitation of the knowledge offers the possibility to search for new biocontrol methods against weeds based on soil and plant-associated microorganisms. This review discusses the recent advances in understanding the functions of microbial communities for weed/invasive plant establishment and shows new ways to use plant-associated microorganisms to control weeds and invasive plants in different land management systems. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The relationship between parenting, family interaction and childhood dental caries: a case-control study

NARCIS (Netherlands)

de Jong-Lenters, M.; Duijster, D.; Bruist, M.A.; Thijssen, J.; de Ruiter, C.

2014-01-01

The aim of this case-control study was to explore the relationship between parenting practices, parent-child interaction and childhood dental caries, using a sample of 5-8-year old children from the Netherlands. Cases were defined as children with four or more decayed, missing or filled teeth and

The relationship between parenting, family interaction and childhood dental caries: A case-control study

NARCIS (Netherlands)

Jong-Lenters, M. de; Duijster, D.; Bruist, M.A.; Thijssen, J.; Ruiter, C. de

2014-01-01

The aim of this case-control study was to explore the relationship between parenting practices, parent-child interaction and childhood dental caries, using a sample of 5-8-year old children from the Netherlands. Cases were defined as children with four or more decayed, missing or filled teeth and

The Effects of Variations in Lesson Control and Practice on Learning from Interactive Video.

Science.gov (United States)

Hannafin, Michael J.; Colamaio, MaryAnne E.

1987-01-01

Discussion of the effects of variations in lesson control and practice on the learning of facts, procedures, and problem-solving skills during interactive video instruction focuses on a study of graduates and advanced level undergraduates learning cardiopulmonary resuscitation (CPR). Embedded questioning methods and posttests used are described.…

Three-way interaction between biological control insects, a congener and their shared parasitoid: Evidence of biotic resistance

Science.gov (United States)

Invasive plants are one of the strongest drivers of species extinctions. Weed biological control offers a sustainable and safe means of long-term population reduction of their target. Herbivores introduced for the control of invasive plants interact with the native community in addition to the top-d...

Control of ion beam generation in intense short pulse laser target interaction

International Nuclear Information System (INIS)

Nagashima, T.; Izumiyama, T.; Barada, D.; Kawata, S.; Gu, Y.J.; Wang, W.M.; Ma, Y.Y.; Kong, Q.

2013-01-01

In intense laser plasma interaction, several issues still remain to be solved for future laser particle acceleration. In this paper we focus on a control of generation of high-energy ions. In this study, near-critical density plasmas are employed and are illuminated by high intensity short laser pulses; we have successfully generated high-energy ions, and also controlled ion energy and the ion energy spectrum by multiple-stages acceleration. We performed particle-in-cell simulations in this paper. The first near-critical plasma target is illuminated by a laser pulse, and the ions accelerated are transferred to the next target. The next identical target is also illuminated by another identical large pulse, and the ion beam introduced is further accelerated and controlled. In this study four stages are employed, and finally a few hundreds of MeV of protons are realized. A quasi-monoenergetic energy spectrum is also obtained. (author)

Comparison of cell homogenization methods considering interaction effect between fuel cells and control rod cells

International Nuclear Information System (INIS)

Takeda, T.; Uto, N.

1988-01-01

Several methods to determine cell-averaged group cross sections and anisotropic diffusion coefficients which consider the interaction effect between core fuel cells and control rods or control rod followers have been compared to discuss the physical meaning included in cell homogenization. As the cell homogenization methods considered are the commonly used flux-weighting method, the reaction rate preservation method and the reactivity preservation method. These homogenization methods have been applied to control rod worth calculations in 1-D slab cores to investigate their applicability. (author). 6 refs, 2 figs, 9 tabs

Particle ''swarm'' dynamics in triboelectric systems

International Nuclear Information System (INIS)

Vinay, Stephen J.; Jhon, Myung S.

2001-01-01

Using state-of-the-art flow/particle visualization and animation techniques, the time-dependent statistical distributions of charged-particle ''swarms'' exposed to external fields (both electrostatic and flow) are examined. We found that interparticle interaction and drag forces mainly influenced swarm dispersion in a Lagrangian reference frame, whereas the average particle trajectory was affected primarily by the external electric and flow fields

Optical binding of two microparticles levitated in vacuum

Science.gov (United States)

Arita, Yoshihiko; Wright, Ewan M.; Dholakia, Kishan

2017-04-01

Optical binding refers to an optically mediated inter-particle interaction that creates new equilibrium positions for closely spaced particles [1-5]. Optical binding of mesoscopic particles levitated in vacuum can pave the way towards the realisation of a large scale quantum bound array in cavity-optomechanics [6-9]. Recently we have demonstrated trapping and rotation of two mesoscopic particles in vacuum using a spatial-light-modulator-based approach to trap more than one particle, induce controlled rotation of individual particles, and mediate interparticle separation [10]. By trapping and rotating two vaterite particles, we observe intensity modulation of the scattered light at the sum and difference frequencies with respect to the individual rotation rates. This first demonstration of optical interference between two microparticles in vacuum has lead to a platform to explore optical binding. Here we demonstrate for the first time optically bound two microparticles mediated by light scattering in vacuum. We investigate autocorrelations between the two normal modes of oscillation, which are determined by the centre-of-mass and the relative positions of the two-particle system. In situ determination of the optical restoring force acting on the bound particles are based on measurement of the oscillation frequencies of the autocorrelation functions of the two normal modes, thereby providing a powerful and original platform to explore multiparticle entanglement in cavity-optomechanics.

Determinants of aggressive behavior: Interactive effects of emotional regulation and inhibitory control.

Directory of Open Access Journals (Sweden)

I-Ju Hsieh

Full Text Available Aggressive behavior can be defined as any behavior intended to hurt another person, and it is associated with many individual and social factors. This study examined the relationship between emotional regulation and inhibitory control in predicting aggressive behavior. Seventy-eight participants (40 males completed self-report measures (Negative Mood Regulation Scale and Buss-Perry Aggression Questionnaire, a stop signal task, and engaged in a modified version of Taylor Aggression Paradigm (TAP exercise, in which the outcome was used as a measure of direct physical aggression. We used a hierarchical, mixed-model multiple regression analysis test to examine the effects of emotion regulation and inhibitory control on physical reactive aggression. Results indicated an interaction between emotion regulation and inhibitory control on aggression. For participants with low inhibitory control only, there was a significant difference between high and low emotion regulation on aggression, such that low emotion regulation participants registered higher aggression than high emotion regulation participants. This difference was not found among participants with high inhibitory control. These results have implications for refining and targeting training and rehabilitation programs aimed at reducing aggressive behavior.

Interaction design challenges and solutions for ALMA operations monitoring and control

Science.gov (United States)

Pietriga, Emmanuel; Cubaud, Pierre; Schwarz, Joseph; Primet, Romain; Schilling, Marcus; Barkats, Denis; Barrios, Emilio; Vila Vilaro, Baltasar

2012-09-01

The ALMA radio-telescope, currently under construction in northern Chile, is a very advanced instrument that presents numerous challenges. From a software perspective, one critical issue is the design of graphical user interfaces for operations monitoring and control that scale to the complexity of the system and to the massive amounts of data users are faced with. Early experience operating the telescope with only a few antennas has shown that conventional user interface technologies are not adequate in this context. They consume too much screen real-estate, require many unnecessary interactions to access relevant information, and fail to provide operators and astronomers with a clear mental map of the instrument. They increase extraneous cognitive load, impeding tasks that call for quick diagnosis and action. To address this challenge, the ALMA software division adopted a user-centered design approach. For the last two years, astronomers, operators, software engineers and human-computer interaction researchers have been involved in participatory design workshops, with the aim of designing better user interfaces based on state-of-the-art visualization techniques. This paper describes the process that led to the development of those interface components and to a proposal for the science and operations console setup: brainstorming sessions, rapid prototyping, joint implementation work involving software engineers and human-computer interaction researchers, feedback collection from a broader range of users, further iterations and testing.

Observation of Hamiltonian chaos and its control in wave-particle interaction

International Nuclear Information System (INIS)

Doveil, F; Macor, A; Aissi, A

2007-01-01

Wave-particle interactions are central in plasma physics. They can be studied in a traveling wave tube (TWT) to avoid intrinsic plasma noise. This led to detailed experimental analysis of the self-consistent interaction between unstable waves and an either cold or warm beam. More recently a test cold electron beam has been used to observe its non-self-consistent interaction with externally excited wave(s). The velocity distribution function of the electron beam is recorded with a trochoidal energy analyzer at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the slow wave structure (a 4 m long helix) of the TWT. The nonlinear synchronization of particles by a single wave responsible for Landau damping is observed. The resonant velocity domain associated with a single wave is also observed, as well as the transition to large scale chaos when the resonant domains of two waves and their secondary resonances overlap. This transition exhibits a 'devil's staircase' behavior when increasing the excitation amplitude in agreement with numerical simulation. A new strategy for control of chaos by building barriers of transport which prevent electrons from escaping from a given velocity region as well as its robustness are successfully tested. The underlying concepts extend far beyond the field of electron devices and plasma physics

Parent-child interactions during traditional and interactive media settings: A pilot randomized control study.

Science.gov (United States)

Skaug, Silje; Englund, Kjellrun T; Saksvik-Lehouillier, Ingvild; Lydersen, Stian; Wichstrøm, Lars

2018-04-01

Parent-child interactions are pivotal for children's socioemotional development, yet might suffer with increased attention to screen media, as research has suggested. In response, we hypothesized that parent-child play on a tablet computer, as representative of interactive media, would generate higher-quality parent-child interactions than toy play or watching TV. We examined the emotional availability of mothers and their 2-year-old child during the previous three contexts using a randomized crossover design (n = 22) in a laboratory room. Among other results, mothers were more sensitive and structuring during joint gaming on a tablet than when engaged in toy play or watching TV. In addition, mothers were more hostile toward their children during play with traditional toys than during joint tablet gaming and television co-viewing. Such findings provide new insights into the impact of new media on parent-child interactions, chiefly by demonstrating that interactive media devices such as tablets can afford growth-enhancing parent-child interactions. © 2017 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Characterization of Aerodynamic Interactions with the Mars Science Laboratory Reaction Control System Using Computation and Experiment

Science.gov (United States)

Schoenenberger, Mark; VanNorman, John; Rhode, Matthew; Paulson, John

2013-01-01

On August 5 , 2012, the Mars Science Laboratory (MSL) entry capsule successfully entered Mars' atmosphere and landed the Curiosity rover in Gale Crater. The capsule used a reaction control system (RCS) consisting of four pairs of hydrazine thrusters to fly a guided entry. The RCS provided bank control to fly along a flight path commanded by an onboard computer and also damped unwanted rates due to atmospheric disturbances and any dynamic instabilities of the capsule. A preliminary assessment of the MSL's flight data from entry showed that the capsule flew much as predicted. This paper will describe how the MSL aerodynamics team used engineering analyses, computational codes and wind tunnel testing in concert to develop the RCS system and certify it for flight. Over the course of MSL's development, the RCS configuration underwent a number of design iterations to accommodate mechanical constraints, aeroheating concerns and excessive aero/RCS interactions. A brief overview of the MSL RCS configuration design evolution is provided. Then, a brief description is presented of how the computational predictions of RCS jet interactions were validated. The primary work to certify that the RCS interactions were acceptable for flight was centered on validating computational predictions at hypersonic speeds. A comparison of computational fluid dynamics (CFD) predictions to wind tunnel force and moment data gathered in the NASA Langley 31-Inch Mach 10 Tunnel was the lynch pin to validating the CFD codes used to predict aero/RCS interactions. Using the CFD predictions and experimental data, an interaction model was developed for Monte Carlo analyses using 6-degree-of-freedom trajectory simulation. The interaction model used in the flight simulation is presented.

Angle-adjustable density field formulation for the modeling of crystalline microstructure

Science.gov (United States)

Wang, Zi-Le; Liu, Zhirong; Huang, Zhi-Feng

2018-05-01

A continuum density field formulation with particle-scale resolution is constructed to simultaneously incorporate the orientation dependence of interparticle interactions and the rotational invariance of the system, a fundamental but challenging issue in modeling the structure and dynamics of a broad range of material systems across variable scales. This generalized phase field crystal-type approach is based upon the complete expansion of particle direct correlation functions and the concept of isotropic tensors. Through applications to the modeling of various two- and three-dimensional crystalline structures, our study demonstrates the capability of bond-angle control in this continuum field theory and its effects on the emergence of ordered phases, and provides a systematic way of performing tunable angle analyses for crystalline microstructures.

Molecular mechanisms of nematode-nematophagous microbe interactions: basis for biological control of plant-parasitic nematodes.

Science.gov (United States)

Li, Juan; Zou, Chenggang; Xu, Jianping; Ji, Xinglai; Niu, Xuemei; Yang, Jinkui; Huang, Xiaowei; Zhang, Ke-Qin

2015-01-01

Plant-parasitic nematodes cause significant damage to a broad range of vegetables and agricultural crops throughout the world. As the natural enemies of nematodes, nematophagous microorganisms offer a promising approach to control the nematode pests. Some of these microorganisms produce traps to capture and kill the worms from the outside. Others act as internal parasites to produce toxins and virulence factors to kill the nematodes from within. Understanding the molecular basis of microbe-nematode interactions provides crucial insights for developing effective biological control agents against plant-parasitic nematodes. Here, we review recent advances in our understanding of the interactions between nematodes and nematophagous microorganisms, with a focus on the molecular mechanisms by which nematophagous microorganisms infect nematodes and on the nematode defense against pathogenic attacks. We conclude by discussing several key areas for future research and development, including potential approaches to apply our recent understandings to develop effective biocontrol strategies.

Robust Control of a Cable-Driven Soft Exoskeleton Joint for Intrinsic Human-Robot Interaction.

Science.gov (United States)

Jarrett, C; McDaid, A J

2017-07-01

A novel, cable-driven soft joint is presented for use in robotic rehabilitation exoskeletons to provide intrinsic, comfortable human-robot interaction. The torque-displacement characteristics of the soft elastomeric core contained within the joint are modeled. This knowledge is used in conjunction with a dynamic system model to derive a sliding mode controller (SMC) to implement low-level torque control of the joint. The SMC controller is experimentally compared with a baseline feedback-linearised proportional-derivative controller across a range of conditions and shown to be robust to un-modeled disturbances. The torque controller is then tested with six healthy subjects while they perform a selection of activities of daily living, which has validated its range of performance. Finally, a case study with a participant with spastic cerebral palsy is presented to illustrate the potential of both the joint and controller to be used in a physiotherapy setting to assist clinical populations.

Micro-Ramp Flow Control for Oblique Shock Interactions: Comparisons of Computational and Experimental Data

Science.gov (United States)

Hirt, Stephanie M.; Reich, David B.; O'Connor, Michael B.

2012-01-01

Computational fluid dynamics was used to study the effectiveness of micro-ramp vortex generators to control oblique shock boundary layer interactions. Simulations were based on experiments previously conducted in the 15- by 15-cm supersonic wind tunnel at the NASA Glenn Research Center. Four micro-ramp geometries were tested at Mach 2.0 varying the height, chord length, and spanwise spacing between micro-ramps. The overall flow field was examined. Additionally, key parameters such as boundary-layer displacement thickness, momentum thickness and incompressible shape factor were also examined. The computational results predicted the effects of the microramps well, including the trends for the impact that the devices had on the shock boundary layer interaction. However, computing the shock boundary layer interaction itself proved to be problematic since the calculations predicted more pronounced adverse effects on the boundary layer due to the shock than were seen in the experiment.

Interactions Controlling the Slow Dynamic Conformational Motions of Ubiquitin

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Soichiro Kitazawa

2017-08-01

Full Text Available Rational mutation of proteins based on their structural and dynamic characteristics is a useful strategy for amplifying specific fluctuations in proteins. Here, we show the effects of mutation on the conformational fluctuations and thermodynamic stability of ubiquitin. In particular, we focus on the salt bridge between K11 and E34 and the hydrogen bond between I36 and Q41, which are predicted to control the fluctuation between the basic folded state, N1, and the alternatively folded state, N2, of the protein, using high-pressure NMR spectroscopy. The E34A mutation, which disrupts the salt bridge, did not alter picosecond–to–nanosecond, microsecond–to–millisecond dynamic motions, and stability of the protein, while the Q41N mutation, which destabilizes the hydrogen bond, specifically amplified the N1–N2 conformational fluctuation and decreased stability. Based on the observed thermodynamic stabilities of the various conformational states, we showed that in the Q41N mutant, the N1 state is more significantly destabilized than the N2 state, resulting in an increase in the relative population of N2. Identifying the interactions controlling specific motions of a protein will facilitate molecular design to achieve functional dynamics beyond native state dynamics.

Initial Drug Dissolution from Amorphous Solid Dispersions Controlled by Polymer Dissolution and Drug-Polymer Interaction.

Science.gov (United States)

Chen, Yuejie; Wang, Shujing; Wang, Shan; Liu, Chengyu; Su, Ching; Hageman, Michael; Hussain, Munir; Haskell, Roy; Stefanski, Kevin; Qian, Feng

2016-10-01

To identify the key formulation factors controlling the initial drug and polymer dissolution rates from an amorphous solid dispersion (ASD). Ketoconazole (KTZ) ASDs using PVP, PVP-VA, HMPC, or HPMC-AS as polymeric matrix were prepared. For each drug-polymer system, two types of formulations with the same composition were prepared: 1. Spray dried dispersion (SDD) that is homogenous at molecular level, 2. Physical blend of SDD (80% drug loading) and pure polymer (SDD-PB) that is homogenous only at powder level. Flory-Huggins interaction parameters (χ) between KTZ and the four polymers were obtained by Flory-Huggins model fitting. Solution (13)C NMR and FT-IR were conducted to investigate the specific drug-polymer interaction in the solution and solid state, respectively. Intrinsic dissolution of both the drug and the polymer from ASDs were studied using a Higuchi style intrinsic dissolution apparatus. PXRD and confocal Raman microscopy were used to confirm the absence of drug crystallinity on the tablet surface before and after dissolution study. In solid state, KTZ is completely miscible with PVP, PVP-VA, or HPMC-AS, demonstrated by the negative χ values of -0.36, -0.46, -1.68, respectively; while is poorly miscible with HPMC shown by a positive χ value of 0.23. According to solution (13)C NMR and FT-IR studies, KTZ interacts with HPMC-AS strongly through H-bonding and dipole induced interaction; with PVPs and PVP-VA moderately through dipole-induced interactions; and with HPMC weakly without detectable attractive interaction. Furthermore, the "apparent" strength of drug-polymer interaction, measured by the extent of peak shift on NMR or FT-IR spectra, increases with the increasing number of interacting drug-polymer pairs. For ASDs with the presence of considerable drug-polymer interactions, such as KTZ/PVPs, KTZ/PVP-VA, or KTZ /HPMC-AS systems, drug released at the same rate as the polymer when intimate drug-polymer mixing was ensured (i.e., the SDD systems

Synchrotron radiation and atom pair correlation functions in electrolyte solutions

International Nuclear Information System (INIS)

Triolo, R.; D'Aprano, A.

1978-01-01

Despite the enormous effort invested in experimental determinations of the properties of water and aqueous solutions, understanding is still rudimentary. Many of the problems are consequences of a nonrigorous definition of interparticle interactions. It is now clear that after properly ion--water interactions in terms of probability functions of position and orientation it is possible to probe these interactions at molecular levels using diffraction experiments. The role of synchrotron x-ray radiation in this context is being examined. Emphasis is given to the possibility of performing different experiments analogous to those done using the isotopic substitution method in neutron diffraction

Depth camera-based 3D hand gesture controls with immersive tactile feedback for natural mid-air gesture interactions.

Science.gov (United States)

Kim, Kwangtaek; Kim, Joongrock; Choi, Jaesung; Kim, Junghyun; Lee, Sangyoun

2015-01-08

Vision-based hand gesture interactions are natural and intuitive when interacting with computers, since we naturally exploit gestures to communicate with other people. However, it is agreed that users suffer from discomfort and fatigue when using gesture-controlled interfaces, due to the lack of physical feedback. To solve the problem, we propose a novel complete solution of a hand gesture control system employing immersive tactile feedback to the user's hand. For this goal, we first developed a fast and accurate hand-tracking algorithm with a Kinect sensor using the proposed MLBP (modified local binary pattern) that can efficiently analyze 3D shapes in depth images. The superiority of our tracking method was verified in terms of tracking accuracy and speed by comparing with existing methods, Natural Interaction Technology for End-user (NITE), 3D Hand Tracker and CamShift. As the second step, a new tactile feedback technology with a piezoelectric actuator has been developed and integrated into the developed hand tracking algorithm, including the DTW (dynamic time warping) gesture recognition algorithm for a complete solution of an immersive gesture control system. The quantitative and qualitative evaluations of the integrated system were conducted with human subjects, and the results demonstrate that our gesture control with tactile feedback is a promising technology compared to a vision-based gesture control system that has typically no feedback for the user's gesture inputs. Our study provides researchers and designers with informative guidelines to develop more natural gesture control systems or immersive user interfaces with haptic feedback.

Depth Camera-Based 3D Hand Gesture Controls with Immersive Tactile Feedback for Natural Mid-Air Gesture Interactions

Directory of Open Access Journals (Sweden)

Kwangtaek Kim

2015-01-01

Full Text Available Vision-based hand gesture interactions are natural and intuitive when interacting with computers, since we naturally exploit gestures to communicate with other people. However, it is agreed that users suffer from discomfort and fatigue when using gesture-controlled interfaces, due to the lack of physical feedback. To solve the problem, we propose a novel complete solution of a hand gesture control system employing immersive tactile feedback to the user’s hand. For this goal, we first developed a fast and accurate hand-tracking algorithm with a Kinect sensor using the proposed MLBP (modified local binary pattern that can efficiently analyze 3D shapes in depth images. The superiority of our tracking method was verified in terms of tracking accuracy and speed by comparing with existing methods, Natural Interaction Technology for End-user (NITE, 3D Hand Tracker and CamShift. As the second step, a new tactile feedback technology with a piezoelectric actuator has been developed and integrated into the developed hand tracking algorithm, including the DTW (dynamic time warping gesture recognition algorithm for a complete solution of an immersive gesture control system. The quantitative and qualitative evaluations of the integrated system were conducted with human subjects, and the results demonstrate that our gesture control with tactile feedback is a promising technology compared to a vision-based gesture control system that has typically no feedback for the user’s gesture inputs. Our study provides researchers and designers with informative guidelines to develop more natural gesture control systems or immersive user interfaces with haptic feedback.

Interaction effect of psychological distress and asthma control on productivity loss?

Science.gov (United States)

Moullec, Grégory; FitzGerald, J Mark; Rousseau, Roxanne; Chen, Wenjia; Sadatsafavi, Mohsen

2015-06-01

Little is known about the potential synergistic effect of comorbid psychological distress (PD) and uncontrolled asthma (UA) on productivity loss. We estimated the productivity loss associated with the combination of these two potentially preventable conditions in employed adults with asthma. A population-based random sample of 300 adults with asthma in British Columbia, Canada, was prospectively recruited between Dec 2010 and Aug 2012. PD and productivity loss due to absenteeism and presenteeism was measured using validated instruments, and asthma control was ascertained using 2010 Global Initiative for Asthma management strategy. We used two-part regression models to study the contribution of UA and PD to productivity loss. Compared with reference group (controlled asthma (CA)+noPD), those with UA+noPD had CAD$286 (95%CI $276-297) weekly productivity loss, and those with CA+PD had CAD$465 ($445-485). Those with UA+PD had CAD$449 (437-462) in productivity loss. There was no significant interaction effect of PD with asthma control levels on productivity loss (p=0.22). In patients without PD, uncontrolled asthma was associated with a higher productivity loss than controlled asthma, but this was not the case in patients with PD. This finding can be explained by the fact that the contribution of PD to productivity loss is so large that there is no room for synergy with asthma control. Future studies should assess the impact of interventions that modify PD in patients with asthma. Copyright ©ERS 2015.

Gaze-and-brain-controlled interfaces for human-computer and human-robot interaction

Directory of Open Access Journals (Sweden)

Shishkin S. L.

2017-09-01

Full Text Available Background. Human-machine interaction technology has greatly evolved during the last decades, but manual and speech modalities remain single output channels with their typical constraints imposed by the motor system’s information transfer limits. Will brain-computer interfaces (BCIs and gaze-based control be able to convey human commands or even intentions to machines in the near future? We provide an overview of basic approaches in this new area of applied cognitive research. Objective. We test the hypothesis that the use of communication paradigms and a combination of eye tracking with unobtrusive forms of registering brain activity can improve human-machine interaction. Methods and Results. Three groups of ongoing experiments at the Kurchatov Institute are reported. First, we discuss the communicative nature of human-robot interaction, and approaches to building a more e cient technology. Specifically, “communicative” patterns of interaction can be based on joint attention paradigms from developmental psychology, including a mutual “eye-to-eye” exchange of looks between human and robot. Further, we provide an example of “eye mouse” superiority over the computer mouse, here in emulating the task of selecting a moving robot from a swarm. Finally, we demonstrate a passive, noninvasive BCI that uses EEG correlates of expectation. This may become an important lter to separate intentional gaze dwells from non-intentional ones. Conclusion. The current noninvasive BCIs are not well suited for human-robot interaction, and their performance, when they are employed by healthy users, is critically dependent on the impact of the gaze on selection of spatial locations. The new approaches discussed show a high potential for creating alternative output pathways for the human brain. When support from passive BCIs becomes mature, the hybrid technology of the eye-brain-computer (EBCI interface will have a chance to enable natural, fluent, and the

Study on the fine control of atoms by coherent interaction

International Nuclear Information System (INIS)

Han, Jae Min; Rho, S. P.; Park, H. M.; Lee, K. S.; Rhee, Y. J.; Yi, J. H.; Jeong, D. Y.; Ko, K. H.; Lee, J. M.; Kim, M.K.

2000-01-01

Study on one dimensional atom cooling and trapping process which is basic to the development of atom manipulation technology has been performed. A Zeeman slower has been designed and manufactured for efficient cooling of atoms. The speed of atoms finally achieved is as slow as 15 m/s with proper cooling conditions. By six circularly-polarized laser beams and quadrupole magnetic field, the atoms which have been slowed down by zeeman slower have been trapped in a small spatial region inside MOT. The higher the intensity of the slowing laser is the more is the number of atoms slowed and the maximum number of atoms trapped has been 10 8 . The atoms of several tens of μK degree have been trapped by controlling the intensity of trapping laser and intensity gradient of magnetic field. EIT phenomena caused by atomic coherent interaction has been studied for the development of atom optical elements. For the investigation of the focusing phenomena induced by the coherent interaction, experimental measurements and theoretical analysis have been performed. Spatial dependency of spectrum and double distribution signal of coupling laser have been obtained. The deflection of laser beams utilizing the EIT effects has also been considered. (author)

Autonomic control of cardiorespiratory interactions in fish, amphibians and reptiles

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E.W. Taylor

2010-07-01

Full Text Available Control of the heart rate and cardiorespiratory interactions (CRI is predominantly parasympathetic in all jawed vertebrates, with the sympathetic nervous system having some influence in tetrapods. Respiratory sinus arrhythmia (RSA has been described as a solely mammalian phenomenon but respiration-related beat-to-beat control of the heart has been described in fish and reptiles. Though they are both important, the relative roles of feed-forward central control and peripheral reflexes in generating CRI vary between groups of fishes and probably between other vertebrates. CRI may relate to two locations for the vagal preganglionic neurons (VPN and in particular cardiac VPN in the brainstem. This has been described in representatives from all vertebrate groups, though the proportion in each location is variable. Air-breathing fishes, amphibians and reptiles breathe discontinuously and the onset of a bout of breathing is characteristically accompanied by an immediate increase in heart rate plus, in the latter two groups, a left-right shunting of blood through the pulmonary circuit. Both the increase in heart rate and opening of a sphincter on the pulmonary artery are due to withdrawal of vagal tone. An increase in heart rate following a meal in snakes is related to withdrawal of vagal tone plus a non-adrenergic-non-cholinergic effect that may be due to humoral factors released by the gut. Histamine is one candidate for this role.

Autonomic control of cardiorespiratory interactions in fish, amphibians and reptiles.

Science.gov (United States)

Taylor, E W; Leite, C A C; Skovgaard, N

2010-07-01

Control of the heart rate and cardiorespiratory interactions (CRI) is predominantly parasympathetic in all jawed vertebrates, with the sympathetic nervous system having some influence in tetrapods. Respiratory sinus arrhythmia (RSA) has been described as a solely mammalian phenomenon but respiration-related beat-to-beat control of the heart has been described in fish and reptiles. Though they are both important, the relative roles of feed-forward central control and peripheral reflexes in generating CRI vary between groups of fishes and probably between other vertebrates. CRI may relate to two locations for the vagal preganglionic neurons (VPN) and in particular cardiac VPN in the brainstem. This has been described in representatives from all vertebrate groups, though the proportion in each location is variable. Air-breathing fishes, amphibians and reptiles breathe discontinuously and the onset of a bout of breathing is characteristically accompanied by an immediate increase in heart rate plus, in the latter two groups, a left-right shunting of blood through the pulmonary circuit. Both the increase in heart rate and opening of a sphincter on the pulmonary artery are due to withdrawal of vagal tone. An increase in heart rate following a meal in snakes is related to withdrawal of vagal tone plus a non-adrenergic-non-cholinergic effect that may be due to humoral factors released by the gut. Histamine is one candidate for this role.

Bright and dark solitons in the normal dispersion regime of inhomogeneous optical fibers: Soliton interaction and soliton control

International Nuclear Information System (INIS)

Liu Wenjun; Tian Bo; Xu Tao; Sun Kun; Jiang Yan

2010-01-01

Symbolically investigated in this paper is a nonlinear Schroedinger equation with the varying dispersion and nonlinearity for the propagation of optical pulses in the normal dispersion regime of inhomogeneous optical fibers. With the aid of the Hirota method, analytic one- and two-soliton solutions are obtained. Relevant properties of physical and optical interest are illustrated. Different from the previous results, both the bright and dark solitons are hereby derived in the normal dispersion regime of the inhomogeneous optical fibers. Moreover, different dispersion profiles of the dispersion-decreasing fibers can be used to realize the soliton control. Finally, soliton interaction is discussed with the soliton control confirmed to have no influence on the interaction. The results might be of certain value for the study of the signal generator and soliton control.

Speech networks at rest and in action: interactions between functional brain networks controlling speech production

Science.gov (United States)

Fuertinger, Stefan

2015-01-01

Speech production is one of the most complex human behaviors. Although brain activation during speaking has been well investigated, our understanding of interactions between the brain regions and neural networks remains scarce. We combined seed-based interregional correlation analysis with graph theoretical analysis of functional MRI data during the resting state and sentence production in healthy subjects to investigate the interface and topology of functional networks originating from the key brain regions controlling speech, i.e., the laryngeal/orofacial motor cortex, inferior frontal and superior temporal gyri, supplementary motor area, cingulate cortex, putamen, and thalamus. During both resting and speaking, the interactions between these networks were bilaterally distributed and centered on the sensorimotor brain regions. However, speech production preferentially recruited the inferior parietal lobule (IPL) and cerebellum into the large-scale network, suggesting the importance of these regions in facilitation of the transition from the resting state to speaking. Furthermore, the cerebellum (lobule VI) was the most prominent region showing functional influences on speech-network integration and segregation. Although networks were bilaterally distributed, interregional connectivity during speaking was stronger in the left vs. right hemisphere, which may have underlined a more homogeneous overlap between the examined networks in the left hemisphere. Among these, the laryngeal motor cortex (LMC) established a core network that fully overlapped with all other speech-related networks, determining the extent of network interactions. Our data demonstrate complex interactions of large-scale brain networks controlling speech production and point to the critical role of the LMC, IPL, and cerebellum in the formation of speech production network. PMID:25673742

Interaction debugging : an integral approach to analyze human-robot interaction

NARCIS (Netherlands)

Kooijmans, T.; Kanda, T.; Bartneck, C.; Ishiguro, H.; Hagita, N.

2006-01-01

Along with the development of interactive robots, controlled experiments and field trials are regularly conducted to stage human-robot interaction. Experience in this field has shown that analyzing human-robot interaction for evaluation purposes fosters the development of improved systems and the

Ordering of Polystyrene Nanoparticles on Substrates Pre-Coated with Different Polyelectrolyte Architectures

Directory of Open Access Journals (Sweden)

Matthias Karg

2013-06-01

Full Text Available Adjusting the inter-particle distances in ordered nanoparticle arrays can create new nano-devices and is of increasing importance to a number of applications such as nanoelectronics and optical devices. The assembly of negatively charged polystyrene (PS nanoparticles (NPs on Poly(2-(dimethylaminoethyl methacrylate (PDMAEMA brushes, quaternized PDMAEMA brushes and Si/PEI/(PSS/PAH2, was studied using dip- and spin-coating techniques. By dip-coating, two dimensional (2-D, randomly distributed non-close packed particle arrays were assembled on Si/PEI/(PSS/PAH2 and PDMAEMA brushes. The inter-particle repulsion leads to lateral mobility of the particles on these surfaces. The 200 nm diameter PS NPs tended to an inter-particle distance of 350 to 400 nm (center to center. On quaternized PDMAEMA brushes, the strong attractive interaction between the NPs and the brush dominated, leading to clustering of the particles on the brush surface. Particle deposition using spin-coating at low spin rates resulted in hexagonal close-packed multilayer structures on Si/PEI/(PSS/PAH2. Close-packed assemblies with more pronounced defects are also observed on PDMAEMA brushes and QPDMAEMA brushes. In contrast, randomly distributed monolayer NP arrays were achieved at higher spin rates on all polyelectrolyte architectures. The area fraction of the particles decreased with increasing spin rate.

A new adaptive control scheme based on the interacting multiple model (IMM) estimation

International Nuclear Information System (INIS)

Afshari, Hamed H.; Al-Ani, Dhafar; Habibi, Saeid

2016-01-01

In this paper, an Interacting multiple model (IMM) adaptive estimation approach is incorporated to design an optimal adaptive control law for stabilizing an Unmanned vehicle. Due to variations of the forward velocity of the Unmanned vehicle, its aerodynamic derivatives are constantly changing. In order to stabilize the unmanned vehicle and achieve the control objectives for in-flight conditions, one seeks for an adaptive control strategy that can adjust itself to varying flight conditions. In this context, a bank of linear models is used to describe the vehicle dynamics in different operating modes. Each operating mode represents a particular dynamic with a different forward velocity. These models are then used within an IMM filter containing a bank of Kalman filters (KF) in a parallel operating mechanism. To regulate and stabilize the vehicle, a Linear quadratic regulator (LQR) law is designed and implemented for each mode. The IMM structure determines the particular mode based on the stored models and in-flight input-output measurements. The LQR controller also provides a set of controllers; each corresponds to a particular flight mode and minimizes the tracking error. Finally, the ultimate control law is obtained as a weighted summation of all individual controllers whereas weights are obtained using mode probabilities of each operating mode.

Development of Flexible Extremities Protection utilizing Shear Thickening Fluid/Fabric Composites

Science.gov (United States)

2012-01-19

The influence of Interparticle Interactions and Hydrodynamic Forces on Shear Thickening in Concentrated Colloidal Dispersions and Slurries 10...Armor Using Fumed SiO2 Nanoparticles Dispersed into Polyethylene Glycol (PEG) through Sonic Cavitation , NSTI-Nanotech 2006. 2006/05/07 00:00:00...for a wide variety of suspensions such as clay–water [17], calcium carbonate–water [18], polystyrene spheres in silicon oil [19], iron particles in

From dressed particle to dressed mode in plasmas

Energy Technology Data Exchange (ETDEWEB)

Itoh, Sanae-I. [Kyushu Univ., Research Inst. for Applied Mechanics, Kasuga, Fukuoka (Japan); Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan)

2002-05-01

A theoretical method to analyze the strong turbulence in far-nonequilibrium plasma is discussed. In this approach, a test mode is treated being dressed with interactions with other modes. Nonlinear dispersion relation of the dressed mode and statistical treatment of turbulence is briefly explained. Analogue to the method of dressed particle, which has given Balescu-Lenard collision operator for inter-particle collisions, is mentioned. (author)

Phase diagram of a modified Lennard-Jones system

International Nuclear Information System (INIS)

Sakagami, Takahiro; Fuchizaki, Kazuhiro

2010-01-01

The well-known Lennard-Jones potential is modified in such a way that it smoothly vanishes at a certain distance. A system whose interparticle interaction is given by such a potential is referred to as a modified Lennard-Jones system, and is served as a standard system describing simple solids and fluids. A phase diagram is determined based on the free energies obtained through thermodynamic integration.

Interaction of Physical and Chemical Processes Controlling the Environmental Fate and Transport of Lampricides Through Stream-Hyporheic Systems

Science.gov (United States)

Hixson, J.; Ward, A. S.; Schmadel, N.; McConville, M.; Remucal, C.

2016-12-01

The transport and fate of contaminants of emerging concern through the environment is complicated by the heterogeneity of natural systems and the unique reaction pathways of individual compounds. Our current evaluation of risk is often simplified to controls assumed to be homogeneous in space and time. However, we know spatial heterogeneity and time-variable reaction rates complicate predictions of environmental transport and fate, and therefore risk. These complications are the result of the interactions between the physical and chemical systems and the time-variable equilibrium that exists between the two. Compounds that interact with both systems, such as photolytic compounds, require that both components are fully understood in order to predict transport and fate. Release of photolytic compounds occurs through both unintentional releases and intentional loadings. Evaluating risks associated with unintentional releases and implementing best management practices for intentional releases requires an in-depth understanding of the sensitivity of photolytic compounds to external controls. Lampricides, such as 3-trifluoromethyl-4-nitrophenol (TFM), are broadly applied in the Great Lakes system to control the population of invasive sea lamprey. Over-dosing can yield fish kills and other detrimental impacts. Still, planning accounts for time of passage and dilution, but not the interaction of the physical and chemical systems (i.e., storage in the hyporheic zone and time-variable decay rates). In this study, we model a series of TFM applications to test the efficacy of dosing as a function of system characteristics. Overall, our results demonstrate the complexity associated with photo-sensitive compounds through stream-hyporheic systems, and highlight the need to better understand how physical and chemical systems interact to control transport and fate in the environment.

A kernel regression approach to gene-gene interaction detection for case-control studies.

Science.gov (United States)

Larson, Nicholas B; Schaid, Daniel J

2013-11-01

Gene-gene interactions are increasingly being addressed as a potentially important contributor to the variability of complex traits. Consequently, attentions have moved beyond single locus analysis of association to more complex genetic models. Although several single-marker approaches toward interaction analysis have been developed, such methods suffer from very high testing dimensionality and do not take advantage of existing information, notably the definition of genes as functional units. Here, we propose a comprehensive family of gene-level score tests for identifying genetic elements of disease risk, in particular pairwise gene-gene interactions. Using kernel machine methods, we devise score-based variance component tests under a generalized linear mixed model framework. We conducted simulations based upon coalescent genetic models to evaluate the performance of our approach under a variety of disease models. These simulations indicate that our methods are generally higher powered than alternative gene-level approaches and at worst competitive with exhaustive SNP-level (where SNP is single-nucleotide polymorphism) analyses. Furthermore, we observe that simulated epistatic effects resulted in significant marginal testing results for the involved genes regardless of whether or not true main effects were present. We detail the benefits of our methods and discuss potential genome-wide analysis strategies for gene-gene interaction analysis in a case-control study design. © 2013 WILEY PERIODICALS, INC.

Interactive computer-based instruction: Basic material control and accounting demonstration

International Nuclear Information System (INIS)

Keisch, B.

1993-01-01

The use of interactive, computer-based training (CBT) courses can be a time- and resource-saving alternative to formal instruction in a classroom milieu. With CBT, students can proceed at their own pace, fit the study course into their schedule, and avoid the extra time and effort involved in travel and other special arrangements. The demonstration given here is an abbreviated, annotated version of a recently developed course in basic material control and accounting designed for the MC and A novice. The system used is ''Quest'' which includes multi-media capabilities, individual scoring, and built-in result-reporting capabilities for the course administrator. Efficient instruction and training are more important than ever because of the growing numbers of relatively inexperienced persons becoming active in safeguards

Low-Dimensional Nanoparticle Clustering in Polymer Micelles and Their Transverse Relaxivity Rates

Science.gov (United States)

Hickey, Robert J.; Meng, Xin; Zhang, Peijun; Park, So-Jung

2015-01-01

One- or two-dimensional arrays of iron oxide nanoparticles were formed in colloidal assemblies of amphiphilic polymers. Electron tomography imaging revealed that nanoparticles are arranged into one-dimensional strings in magneto-micelles or two-dimensional sheets in magneto-core/shell assemblies. The distinct directional assembly behavior was attributed to the interparticle interaction relative to the nanoparticle–polymer interaction, which was modulated by varying the cosolvent used for the solution phase self-assembly. Magneto-core/shell assemblies with varying structural parameters were formed with a range of different sized as-synthesized nanoparticles. The transverse magnetic relaxivity rates (r2) of a series of different assemblies were determined to examine the effect of nanoparticle arrangement on the magnetic relaxivity for their potential applications in MRI. The results indicated that the assembly structure of nanoparticles in polymer micelles significantly affects the r2 of surrounding water, providing a way to control magnetic relaxivity. PMID:23731021

Ultrasonic and mechanical behavior of green and partially sintered alumina: Effects of slurry consolidation chemistry

Energy Technology Data Exchange (ETDEWEB)

Schilling, C.H.; Garcia, V.J.; Smith, R.M. [Ames Lab., IA (United States)]|[Iowa State Univ., Ames, IA (United States). Dept. of Materials Science and Engineering; Roberts, R.A. [Iowa State Univ., Ames, IA (United States)

1998-10-01

Green and partially sintered compacts of {alpha}-Al{sub 2}O{sub 3} powder were made by filtration of aqueous suspensions under three conditions: (i) electrostatic stabilization without any organic additive, (ii) strong flocculation near the isoelectric point without any organic additive, and (iii) weak flocculation by the use of maltodextrin or oxalic acid additives. The authors evaluated relationships between the macroscopic and interparticle mechanical behavior of these compacts using model correlations with measurements of diametral compression, ultrasonic velocity, and ultrasonic attenuation. Although type iii green specimens were less dense than type i, type iii exhibited significant increases in velocity, macroscopic Young`s modulus, interparticle-contact stiffness, and diametral compressive strength, suggesting that the mechanism of stiffening/strengthening entailed interparticle bridging of maltodextrin or oxalic acid. These properties were significantly reduced upon heating type iii specimens to 500 C, suggesting that pyrolysis of surface-adsorbed maltodextrin and oxalic acid may have reduced the interparticle stiffness and strength. In contrast, negligible changes in these properties occurred upon heating type i specimens to the same temperature. Despite small increases in packing density, significant decreases in attenuation and significant increases in velocity, interparticle-contact stiffness, and Young`s modulus occurred upon heating all specimens to {ge}700 C, suggesting the formation of interparticle necks by solid-state sintering.

Emotional variability during mother-adolescent conflict interactions: Longitudinal links to adolescent disclosure and maternal control

NARCIS (Netherlands)

Van der Giessen, D.; Branje, S.; Keijsers, L.; Van Lier, P.A.C.; Koot, H.M.; Meeus, W.

2014-01-01

The aim of this study was to examine relations of emotional variability during mother-adolescent conflict interactions in early adolescence with adolescent disclosure and maternal control in early and late adolescence. Data were used from 92 mother-adolescent dyads (M age T1 = 13.05; 65.20% boys)

Imaging contrast and tip-sample interaction of non-contact amplitude modulation atomic force microscopy with Q -control

International Nuclear Information System (INIS)

Shi, Shuai; Guo, Dan; Luo, Jianbin

2017-01-01

Active quality factor ( Q ) exhibits many promising properties in dynamic atomic force microscopy. Energy dissipation and image contrasts are investigated in the non-contact amplitude modulation atomic force microscopy (AM-AFM) with an active Q -control circuit in the ambient air environment. Dissipated power and virial were calculated to compare the highly nonlinear interaction of tip-sample and image contrasts with different Q gain values. Greater free amplitudes and lower effective Q values show better contrasts for the same setpoint ratio. Active quality factor also can be employed to change tip-sample interaction force in non-contact regime. It is meaningful that non-destructive and better contrast images can be realized in non-contact AM-AFM by applying an active Q -control to the dynamic system. (paper)

Motion Intention Analysis-Based Coordinated Control for Amputee-Prosthesis Interaction

Directory of Open Access Journals (Sweden)

Fei Wang

2010-01-01

Full Text Available To study amputee-prosthesis (AP interaction, a novel reconfigurable biped robot was designed and fabricated. In homogeneous configuration, two identical artificial legs (ALs were used to simulate the symmetrical lower limbs of a healthy person. Linear inverted pendulum model combining with ZMP stability criterion was used to generate the gait trajectories of ALs. To acquire interjoint coordination for healthy gait, rate gyroscopes were mounted on CoGs of thigh and shank of both legs. By employing principal component analysis, the measured angular velocities were processed and the motion synergy was obtained in the final. Then, one of two ALs was replaced by a bionic leg (BL, and the biped robot was changed into heterogeneous configuration to simulate the AP coupling system. To realize symmetrical stable walking, master/slave coordinated control strategy is proposed. According to information acquired by gyroscopes, BL recognized the motion intention of AL and reconstructed its kinematic variables based on interjoint coordination. By employing iterative learning control, gait tracking of BL to AL was archived. Real environment robot walking experiments validated the correctness and effectiveness of the proposed scheme.

User interaction concept for plasma discharge control on WENDELSTEIN 7-X

International Nuclear Information System (INIS)

Spring, Anett; Laqua, Heike; Niedermeyer, Helmut

2006-01-01

The requirements to the user interfaces arising from the concept of segmented discharges allowing short pulses and steady state operation and from the distributed hierarchical structure of the experiment are discussed. The modular design of the user interfaces is presented including specialised tools for preparation, manipulating, and monitoring the discharge operation. The user guidance and the mapping of complex control procedures onto a physically relevant view on the plasma discharge process will be vitally important. The feasibility of the user interaction concept could already be validated on a prototype installation and during commissioning of the first technical WENDELSTEIN 7-X (W7-X) components

Ferrofluid aggregation in chains under the influence of a magnetic field

International Nuclear Information System (INIS)

Ivanov, Alexey O.; Kantorovich, Sofia S.; Mendelev, Valentin S.; Pyanzina, Elena S.

2006-01-01

The paper is devoted to the basic problem of chain aggregate formation in magnetic fluids under the influence of an external magnetic field. Chain distribution in dynamic equilibrium is obtained on the basis of free energy minimization method under the condition when the interparticle dipole-dipole interaction between the nearest neighboring ferroparticles in each chain is taken into account. The modified mean field approach is used for considering the dipole-dipole interaction between all particles in a ferrofluid. The model describes well the molecular dynamics simulations of magnetostatic properties for monodisperse ferrofluids containing chain aggregates

Interactive urban design using integrated planning requirements control

NARCIS (Netherlands)

Vries, de B.; Tabak, V.; Achten, H.H.

2005-01-01

Urban planning and urban design are separated disciplines. As a consequence, there is hardly any feedback from the urban design process to the urban planning process. To improve interaction between these two, an interactive urban design (IUD) tool has been developed. The tool is implemented in a

Speech networks at rest and in action: interactions between functional brain networks controlling speech production.

Science.gov (United States)

Simonyan, Kristina; Fuertinger, Stefan

2015-04-01

Speech production is one of the most complex human behaviors. Although brain activation during speaking has been well investigated, our understanding of interactions between the brain regions and neural networks remains scarce. We combined seed-based interregional correlation analysis with graph theoretical analysis of functional MRI data during the resting state and sentence production in healthy subjects to investigate the interface and topology of functional networks originating from the key brain regions controlling speech, i.e., the laryngeal/orofacial motor cortex, inferior frontal and superior temporal gyri, supplementary motor area, cingulate cortex, putamen, and thalamus. During both resting and speaking, the interactions between these networks were bilaterally distributed and centered on the sensorimotor brain regions. However, speech production preferentially recruited the inferior parietal lobule (IPL) and cerebellum into the large-scale network, suggesting the importance of these regions in facilitation of the transition from the resting state to speaking. Furthermore, the cerebellum (lobule VI) was the most prominent region showing functional influences on speech-network integration and segregation. Although networks were bilaterally distributed, interregional connectivity during speaking was stronger in the left vs. right hemisphere, which may have underlined a more homogeneous overlap between the examined networks in the left hemisphere. Among these, the laryngeal motor cortex (LMC) established a core network that fully overlapped with all other speech-related networks, determining the extent of network interactions. Our data demonstrate complex interactions of large-scale brain networks controlling speech production and point to the critical role of the LMC, IPL, and cerebellum in the formation of speech production network. Copyright © 2015 the American Physiological Society.

Interactions of Circadian Rhythmicity, Stress and Orexigenic Neuropeptide Systems: Implications for Food Intake Control.

Science.gov (United States)

Blasiak, Anna; Gundlach, Andrew L; Hess, Grzegorz; Lewandowski, Marian H

2017-01-01

Many physiological processes fluctuate throughout the day/night and daily fluctuations are observed in brain and peripheral levels of several hormones, neuropeptides and transmitters. In turn, mediators under the "control" of the "master biological clock" reciprocally influence its function. Dysregulation in the rhythmicity of hormone release as well as hormone receptor sensitivity and availability in different tissues, is a common risk-factor for multiple clinical conditions, including psychiatric and metabolic disorders. At the same time circadian rhythms remain in a strong, reciprocal interaction with the hypothalamic-pituitary-adrenal (HPA) axis. Recent findings point to a role of circadian disturbances and excessive stress in the development of obesity and related food consumption and metabolism abnormalities, which constitute a major health problem worldwide. Appetite, food intake and energy balance are under the influence of several brain neuropeptides, including the orexigenic agouti-related peptide, neuropeptide Y, orexin, melanin-concentrating hormone and relaxin-3. Importantly, orexigenic neuropeptide neurons remain under the control of the circadian timing system and are highly sensitive to various stressors, therefore the potential neuronal mechanisms through which disturbances in the daily rhythmicity and stress-related mediator levels contribute to food intake abnormalities rely on reciprocal interactions between these elements.

Are Children with Autism More Responsive to Animated Characters? A Study of Interactions with Humans and Human-Controlled Avatars

Science.gov (United States)

Carter, Elizabeth J.; Williams, Diane L.; Hodgins, Jessica K.; Lehman, Jill F.

2014-01-01

Few direct comparisons have been made between the responsiveness of children with autism to computer-generated or animated characters and their responsiveness to humans. Twelve 4-to 8-year-old children with autism interacted with a human therapist; a human-controlled, interactive avatar in a theme park; a human actor speaking like the avatar; and…

78 FR 37570 - Certain Products Containing Interactive Program Guide and Parental Control Technology; Notice of...

Science.gov (United States)

2013-06-21

... Interactive Program Guide and Parental Control Technology; Notice of Request for Statements on the Public... questions regarding filing should contact the Secretary (202-205-2000). Any person desiring to submit a... taken under the authority of section 337 of the Tariff Act of 1930, as amended (19 U.S.C. 1337), and of...

Interacting With Robots to Investigate the Bases of Social Interaction.

Science.gov (United States)

Sciutti, Alessandra; Sandini, Giulio

2017-12-01

Humans show a great natural ability at interacting with each other. Such efficiency in joint actions depends on a synergy between planned collaboration and emergent coordination, a subconscious mechanism based on a tight link between action execution and perception. This link supports phenomena as mutual adaptation, synchronization, and anticipation, which cut drastically the delays in the interaction and the need of complex verbal instructions and result in the establishment of joint intentions, the backbone of social interaction. From a neurophysiological perspective, this is possible, because the same neural system supporting action execution is responsible of the understanding and the anticipation of the observed action of others. Defining which human motion features allow for such emergent coordination with another agent would be crucial to establish more natural and efficient interaction paradigms with artificial devices, ranging from assistive and rehabilitative technology to companion robots. However, investigating the behavioral and neural mechanisms supporting natural interaction poses substantial problems. In particular, the unconscious processes at the basis of emergent coordination (e.g., unintentional movements or gazing) are very difficult-if not impossible-to restrain or control in a quantitative way for a human agent. Moreover, during an interaction, participants influence each other continuously in a complex way, resulting in behaviors that go beyond experimental control. In this paper, we propose robotics technology as a potential solution to this methodological problem. Robots indeed can establish an interaction with a human partner, contingently reacting to his actions without losing the controllability of the experiment or the naturalness of the interactive scenario. A robot could represent an "interactive probe" to assess the sensory and motor mechanisms underlying human-human interaction. We discuss this proposal with examples from our

Cardiorespiratory interactions in neural circulatory control in humans.

Science.gov (United States)

Shamsuzzaman, A S; Somers, V K

2001-06-01

The reflex mechanisms and interactions described in this overview provide some explanation for the range of neural circulatory responses evident during changes in breathing. The effects described represent the integrated responses to activation of several reflex mechanisms, including peripheral and central chemoreflexes, arterial baroreflexes, pulmonary stretch receptors, and ventricular mechanoreceptors. These interactions occur on a dynamic basis and the transfer characteristics of any single interaction are, in all likelihood, also highly dynamic. Nevertheless, it is only by attempting to understand individual reflexes and their modulating influences that a more thorough understanding of the responses to complex phenomena such as hyperventilation, apnea, and obstructive sleep apnea can be better understood.

Challenges of implementing economic model predictive control strategy for buildings interacting with smart energy systems

DEFF Research Database (Denmark)

Zong, Yi; Böning, Georg Martin; Santos, Rui Mirra

2016-01-01

) strategy for energy management in smart buildings, which can act as active users interacting with smart energy systems. The challenges encountered during the implementation of EMPC for active demand side management are investigated in detail in this paper. A pilot testing study shows energy savings......When there is a high penetration of renewables in the energy system, it requires proactive control of large numbers of distributed demand response resources to maintain the system’s reliability and improve its operational economics. This paper presents the Economic Model Predictive Control (EMPC...

Exploring direct 3D interaction for full horizontal parallax light field displays using leap motion controller.

Science.gov (United States)

Adhikarla, Vamsi Kiran; Sodnik, Jaka; Szolgay, Peter; Jakus, Grega

2015-04-14

This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV) of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

Comparative Study Between the Two Experimental Design Approaches Taguchi and Traditional in Presence of Control by Control Interactions

Directory of Open Access Journals (Sweden)

Arias-Nava Elías Heriberto

2015-03-01

Full Text Available Design of experiments plays an important role in the field of creating and innovating process and products directly in manufacturing and improving areas. There are several areas into designs of experiments; robust design is one of them. Robust parameter design is a principle that emphasize in products creation through a correct selection of values called “control” which make a product robust to the variability by the noise introducing by another factors known as “noise” factors. This article aims for a comparative study between two well-known robust design methodologies, making a special emphasis in the control by control interaction effects over optimal operating conditions. The results showed that Taguchi´s crossed arrays are unable to estimate all significant terms in a model. The optimizations result concludes that the Taguchi´s approach is less efficient than the traditional approach in both; maximization and minimization.

Interfacial magnetic coupling between Fe nanoparticles in Fe–Ag granular alloys

International Nuclear Information System (INIS)

Alonso, J; Fdez-Gubieda, M L; Sarmiento, G; Chaboy, J; Boada, R; García Prieto, A; Haskel, D; Laguna-Marco, M A; Lang, J C; Meneghini, C; Fernández Barquín, L; Neisius, T; Orue, I

2012-01-01

The role of the interface in mediating interparticle magnetic interactions has been analysed in Fe 50 Ag 50 and Fe 55 Ag 45 granular thin films deposited by the pulsed laser deposition technique (PLD). These samples are composed of crystalline bcc Fe (2–4 nm) nanoparticles and fcc Ag (10–12 nm) nanoparticles, separated by an amorphous Fe 50 Ag 50 interface, occupying around 20% of the sample volume, as determined by x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), and high resolution transmission electron microscopy (HRTEM). Interfacial magnetic coupling between Fe nanoparticles is studied by dc magnetization and x-ray magnetic circular dichroism (XMCD) measurements at the Fe K and Ag L 2,3 edges. This paper reveals that these thin films present two magnetic transitions, at low and high temperatures, which are strongly related to the magnetic state of the amorphous interface, which acts as a barrier for interparticle magnetic coupling.

Modified Mason number for charged paramagnetic colloidal suspensions

Science.gov (United States)

Du, Di; Hilou, Elaa; Biswal, Sibani Lisa

2016-06-01

The dynamics of magnetorheological fluids have typically been described by the Mason number, a governing parameter defined as the ratio between viscous and magnetic forces in the fluid. For most experimental suspensions of magnetic particles, surface forces, such as steric and electrostatic interactions, can significantly influence the dynamics. Here we propose a theory of a modified Mason number that accounts for surface forces and show that this modified Mason number is a function of interparticle distance. We demonstrate that this modified Mason number is accurate in describing the dynamics of a rotating pair of paramagnetic colloids of identical or mismatched sizes in either high or low salt solutions. The modified Mason number is confirmed to be pseudoconstant for particle pairs and particle chains undergoing a stable-metastable transition during rotation. The interparticle distance term can be calculated using theory or can be measured experimentally. This modified Mason number is more applicable to magnetorheological systems where surface forces are not negligible.

Influenza A Virus-Host Protein Interactions Control Viral Pathogenesis.

Science.gov (United States)

Zhao, Mengmeng; Wang, Lingyan; Li, Shitao

2017-08-01

The influenza A virus (IAV), a member of the Orthomyxoviridae family, is a highly transmissible respiratory pathogen and represents a continued threat to global health with considerable economic and social impact. IAV is a zoonotic virus that comprises a plethora of strains with different pathogenic profiles. The different outcomes of viral pathogenesis are dependent on the engagement between the virus and the host cellular protein interaction network. The interactions may facilitate virus hijacking of host molecular machinery to fulfill the viral life cycle or trigger host immune defense to eliminate the virus. In recent years, much effort has been made to discover the virus-host protein interactions and understand the underlying mechanisms. In this paper, we review the recent advances in our understanding of IAV-host interactions and how these interactions contribute to host defense and viral pathogenesis.

Modulation of electrostatic interactions to improve controlled drug delivery from nanogels

Energy Technology Data Exchange (ETDEWEB)

Mauri, Emanuele; Chincarini, Giulia M.F.; Rigamonti, Riccardo; Magagnin, Luca; Sacchetti, Alessandro, E-mail: alessandro.sacchetti@polimi.it; Rossi, Filippo, E-mail: filippo.rossi@polimi.it

2017-03-01

The synthesis of nanogels as devices capable to maintain the drug level within a desired range for a long and sustained period of time is a leading strategy in controlled drug delivery. However, with respect to the good results obtained with antibodies and peptides there are a lot of problems related to the quick and uncontrolled diffusion of small hydrophilic molecules through polymeric network pores. For these reasons research community is pointing toward the use of click strategies to reduce release rates of the linked drugs to the polymer chains. Here we propose an alternative method that considers the electrostatic interactions between polymeric chains and drugs to tune the release kinetics from nanogel network. The main advantage of these systems lies in the fact that the carried drugs are not modified and no chemical reactions take place during their loading and release. In this work we synthesized PEG-PEI based nanogels with different protonation degrees and the release kinetics with charged and uncharged drug mimetics (sodium fluorescein, SF, and rhodamine B, RhB) were studied. Moreover, also the effect of counterion used to induce protonation was taken into account in order to build a tunable drug delivery system able to provide multiple release rates with the same device. - Highlights: • The design of nanogels as drug delivery systems based on electrostatic interaction among drug and polymers is proposed. • Nanogels can be synthetized tuning their positive charge density, according to the protonation of PEI at different pH. • No biorthogonal chemistry strategies are applied to the polymers or drugs. • Drug release is efficiently modulated by charge density of PEI chains. • The effect of counterion on nanogel synthesis is investigated and allows controlling the drug release.

Superparamagnetism and coercivity in HCP-Co nanoparticles dispersed in silica matrix

Energy Technology Data Exchange (ETDEWEB)

Julian Fernandez, C. de E-mail: dejulian@padova.infm.it; Mattei, G.; Sangregorio, C.; Battaglin, C.; Gatteschi, D.; Mazzoldi, P

2004-05-01

The magnetic properties of Co HCP nanoparticles dispersed in a silica matrix with sizes between 2{+-}0.7 and 5{+-}2.2 nm were investigated. The temperature dependence of zero-field cooled and field cooled magnetizations and of the coercive field were analyzed considering the thermal activated demagnetization process. Enhanced anisotropy was observed for the 2 nm nanoparticles, while the demagnetization process of the larger ones is dominated by interparticle interactions.

Light-assisted, templated self-assembly of gold nanoparticle chains.

Science.gov (United States)

Jaquay, Eric; Martínez, Luis Javier; Huang, Ningfeng; Mejia, Camilo A; Sarkar, Debarghya; Povinelli, Michelle L

2014-09-10

We experimentally demonstrate the technique of light-assisted, templated self-assembly (LATS) to trap and assemble 200 nm diameter gold nanoparticles. We excite a guided-resonance mode of a photonic-crystal slab with 1.55 μm laser light to create an array of optical traps. Unlike our previous demonstration of LATS with polystyrene particles, we find that the interparticle interactions play a significant role in the resulting particle patterns. Despite a two-dimensionally periodic intensity profile in the slab, the particles form one-dimensional chains whose orientations can be controlled by the incident polarization of the light. The formation of chains can be understood in terms of a competition between the gradient force due to the excitation of the mode in the slab and optical binding between particles.

Bent dark soliton dynamics in two spatial dimensions beyond the mean field approximation

Science.gov (United States)

Mistakidis, Simeon; Katsimiga, Garyfallia; Koutentakis, Georgios; Kevrekidis, Panagiotis; Schmelcher, Peter; Theory Group of Fundamental Processes in Quantum Physics Team

2017-04-01

The dynamics of a bented dark soliton embedded in two spatial dimensions beyond the mean-field approximation is explored. We examine the case of a single bented dark soliton comparing the mean-field approximation to a correlated approach that involves multiple orbitals. Fragmentation is generally present and significantly affects the dynamics, especially in the case of stronger interparticle interactions and in that of lower atom numbers. It is shown that the presence of fragmentation allows for the appearance of solitonic and vortex structures in the higher-orbital dynamics. In particular, a variety of excitations including dark solitons in multiple orbitals and vortex-antidark complexes is observed to arise spontaneously within the beyond mean-field dynamics. Deutsche Forschungsgemeinschaft (DFG) in the framework of the SFB 925 ``Light induced dynamics and control of correlated quantum systems''.

Environmental Controls and Eco-geomorphic Interactions of the Barchan-to-parabolic Dune Stabilisation and the Parabolic-to-barchan Dune Reactivation

Science.gov (United States)

Yan, Na; Baas, Andreas

2015-04-01

Parabolic dunes are one of a few common aeolian landforms which are highly controlled by eco-geomorphic interactions. Parabolic dunes, on the one hand, can be developed from highly mobile dune landforms, barchans for instance, in an ameliorated vegetation condition; or on the other hand, they can be reactivated and transformed back into mobile dunes due to vegetation deterioration. The fundamental mechanisms and eco-geomorphic interactions controlling both dune transformations remain poorly understood. To bridge the gap between complex processes involved in dune transformations on a relatively long temporal scale and real world monitoring records on a very limited temporal scale, this research has extended the DECAL model to incorporate 'dynamic' growth functions and the different 'growth' of perennial shrubs between growing and non-growing seasons, informed by field measurements and remote sensing analysis, to explore environmental controls and eco-geomorphic interactions of both types of dune transformation. A non-dimensional 'dune stabilising index' is proposed to capture the interactions between environmental controls (i.e. the capabilities of vegetation to withstand wind erosion and sand burial, the sandy substratum thickness, the height of the initial dune, and the sand transport potential), and establish the linkage between these controls and the geometry of a stabilising dune. An example demonstrates how to use the power-law relationship between the dune stabilising index and the normalised migration distance to assist in extrapolating the historical trajectories of transforming dunes. The modelling results also show that a slight increase in vegetation cover of an initial parabolic dune can significantly increase the reactivation threshold of climatic impact (both drought stress and wind strength) required to reactivate a stabilising parabolic dune into a barchan. Four eco-geomorphic interaction zones that govern a barchan-to-parabolic dune transformation

Interactive scan control for kinematic study in open MRI

International Nuclear Information System (INIS)

Goto, Tomohiro; Hamada, Kiyomi; Ito, Taeko; Nagao, Hisako; Takahashi, Tetsuhiko; Hayashida, Yoshiko; Hiai, Yasuhiro; Yamashita, Yasuyuki

2007-01-01

A tool to support the subject is generally used for kinematic joint imaging with an open MRI apparatus because of difficulty setting the image plane correctly. However, use of a support tool requires a complicated procedure to position the subject, and setting the image plane when the joint angle changes is time consuming. Allowing the subject to move freely enables better diagnoses when kinematic joint imaging is performed. We therefore developed an interactive scan control (ISC) to facilitate the easy, quick, and accurate setting of the image plane even when a support tool is not used. We used a 0.4T magnetic resonance (MR) imaging system open in the horizontal direction. The ISC determines the image plane interactively on the basis of fluoroscopy images displayed on a user interface. The imaging pulse is a balanced steady-state acquisition with rewound gradient echo (SARGE) sequence with update time less than 2 s. Without using a tool to support the knee, we positioned the knee of a healthy volunteer at 4 different joint angles and set the image plane through the patella and femur at each of the angles. Lumbar imaging is also demonstrated with ISC. Setting the image plane was easy and quick at all knee angles, and images obtained clearly showed the patella and femur. Total imaging time was less than 10 min, a fourth of the time needed when a support tool is used. We also used our ISC in kinematic imaging of the lumbar. The ISC shortens total time for kinematic joint imaging, and because a support tool is not needed, imaging can be done more freely in an open MR imaging apparatus. (author)

The Effects of an Interactive Nursing Skills Mobile Application on Nursing Students' Knowledge, Self-efficacy, and Skills Performance: A Randomized Controlled Trial

OpenAIRE

Hyunsun Kim, MSN, RN; Eunyoung E. Suh, PhD, FNP, RN

2018-01-01

Purpose: Clinical nursing practice is important because it helps nursing students experience realities of clinical nursing that cannot be learned through theoretical education. This study aimed to evaluate the effect of an interactive nursing skills mobile application for nursing students. Methods: Sixty-six senior nursing students were randomly assigned to experimental or control groups. The experimental group used an interactive nursing skills mobile application for 1 week. The control grou...

Assessing the interaction effect of cost control systems and information technology integration on manufacturing plant financial performance

OpenAIRE

Maiga, Adam S; Nilsson, Anders; Jacobs, Fred

2014-01-01

The interface between management control and information technology is an under-developed research area with a knowledge gap concerning its implications for financial performance. This study contributes to bridging this gap by investigates the interaction effect of cost control systems and information technology integration on manufacturing plant financial performance. We surveyed a sample of 518 managers of U.S. manufacturing plants, approximately evenly distributed between those using activ...

Effect of bidispersity in grafted chain length on grafted chain conformations and potential of mean force between polymer grafted nanoparticles in a homopolymer matrix.

Science.gov (United States)

Nair, Nitish; Wentzel, Nathaniel; Jayaraman, Arthi

2011-05-21

In efforts to produce polymeric materials with tailored physical properties, significant interest has grown around the ability to control the spatial organization of nanoparticles in polymer nanocomposites. One way to achieve controlled particle arrangement is by grafting the nanoparticle surface with polymers that are compatible with the matrix, thus manipulating the interfacial interactions between the nanoparticles and the polymer matrix. Previous work has shown that the molecular weight of the grafted polymer, both at high grafting density and low grafting density, plays a key role in dictating the effective inter-particle interactions in a polymer matrix. At high grafting density nanoparticles disperse (aggregate) if the graft molecular weight is higher (lower) than the matrix molecular weight. At low grafting density the longer grafts can better shield the nanoparticle surface from direct particle-particle contacts than the shorter grafts and lead to the dispersion of the grafted particles in the matrix. Despite the importance of graft molecular weight, and evidence of non-trivial effects of polydispersity of chains grafted on flat surfaces, most theoretical work on polymer grafted nanoparticles has only focused on monodisperse grafted chains. In this paper, we focus on how bidispersity in grafted chain lengths affects the grafted chain conformations and inter-particle interactions in an implicit solvent and in a dense homopolymer polymer matrix. We first present the effects of bidispersity on grafted chain conformations in a single polymer grafted particle using purely Monte Carlo (MC) simulations. This is followed by calculations of the potential of mean force (PMF) between two grafted particles in a polymer matrix using a self-consistent Polymer Reference Interaction Site Model theory-Monte Carlo simulation approach. Monte Carlo simulations of a single polymer grafted particle in an implicit solvent show that in the bidisperse polymer grafted particles

Controlling the Host-Guest Interaction Mode through a Redox Stimulus.

Science.gov (United States)

Szalóki, György; Croué, Vincent; Carré, Vincent; Aubriet, Frédéric; Alévêque, Olivier; Levillain, Eric; Allain, Magali; Aragó, Juan; Ortí, Enrique; Goeb, Sébastien; Sallé, Marc

2017-12-18

A proof-of-concept related to the redox-control of the binding/releasing process in a host-guest system is achieved by designing a neutral and robust Pt-based redox-active metallacage involving two extended-tetrathiafulvalene (exTTF) ligands. When neutral, the cage is able to bind a planar polyaromatic guest (coronene). Remarkably, the chemical or electrochemical oxidation of the host-guest complex leads to the reversible expulsion of the guest outside the cavity, which is assigned to a drastic change of the host-guest interaction mode, illustrating the key role of counteranions along the exchange process. The reversible process is supported by various experimental data ( 1 H NMR spectroscopy, ESI-FTICR, and spectroelectrochemistry) as well as by in-depth theoretical calculations performed at the density functional theory (DFT) level. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

How thermodynamic environments control stratocumulus microphysics and interactions with aerosols

International Nuclear Information System (INIS)

Andersen, Hendrik; Cermak, Jan

2015-01-01

Aerosol–cloud interactions are central to climate system changes and depend on meteorological conditions. This study identifies distinct thermodynamic regimes and proposes a conceptual framework for interpreting aerosol effects. In the analysis, ten years (2003–2012) of daily satellite-derived aerosol and cloud products are combined with reanalysis data to identify factors controlling Southeast Atlantic stratocumulus microphysics. Considering the seasonal influence of aerosol input from biomass burning, thermodynamic environments that feature contrasting microphysical cloud properties and aerosol–cloud relations are classified. While aerosol impact is stronger in unstable environments, it is mostly confined to situations with low aerosol loading (aerosol index AI ≲ 0.15), implying a saturation of aerosol effects. Situations with high aerosol loading are associated with weaker, seasonally contrasting aerosol-droplet size relationships, likely caused by thermodynamically induced processes and aerosol swelling. (letter)

Plant neighbour identity matters to belowground interactions under controlled conditions.

Science.gov (United States)

Armas, Cristina; Pugnaire, Francisco Ignacio

2011-01-01

Root competition is an almost ubiquitous feature of plant communities with profound effects on their structure and composition. Far beyond the traditional view that plants interact mainly through resource depletion (exploitation competition), roots are known to be able to interact with their environment using a large variety of mechanisms that may inhibit or enhance access of other roots to the resource or affect plant growth (contest interactions). However, an extensive analysis on how these contest root interactions may affect species interaction abilities is almost lacking. In a common garden experiment with ten perennial plant species we forced pairs of plants of the same or different species to overlap their roots and analyzed how belowground contest interactions affected plant performance, biomass allocation patterns, and competitive abilities under abundant resource supply. Our results showed that net interaction outcome ranged from negative to positive, affecting total plant mass and allocation patterns. A species could be a strong competitor against one species, weaker against another one, and even facilitator to a third species. This leads to sets of species where competitive hierarchies may be clear but also to groups where such rankings are not, suggesting that intransitive root interactions may be crucial for species coexistence. The outcome of belowground contest interactions is strongly dependent on neighbours' identity. In natural plant communities this conditional outcome may hypothetically help species to interact in non-hierarchical and intransitive networks, which in turn might promote coexistence.

Context, emotion, and the strategic pursuit of goals: Interactions among multiple brain systems controlling motivated behaviour

Directory of Open Access Journals (Sweden)

Aaron J Gruber

2012-08-01

Full Text Available Motivated behaviour exhibits properties that change with experience and partially dissociate among a number of brain structures. Here, we review evidence from rodent experiments demonstrating that multiple brain systems acquire information in parallel and either cooperate or compete for behavioural control. We propose a conceptual model of systems interaction wherein a ventral emotional memory network involving ventral striatum, amygdala, ventral hippocampus, and ventromedial prefrontal cortex triages behavioural responding to stimuli according to their associated affective outcomes. This system engages autonomic and postural responding (avoiding, ignoring, approaching in accordance with associated stimulus valence (negative, neutral, positive, but does not engage particular operant responses. Rather, this emotional system suppresses or invigorates actions that are selected through competition between goal-directed control involving dorsomedial striatum and habitual control involving dorsolateral striatum. The hippocampus provides contextual specificity to the emotional system, and provides an information rich input to the goal-directed system for navigation and discriminations involving ambiguous contexts, complex sensory configurations, or temporal ordering. The rapid acquisition and high capacity for episodic associations in the emotional system may unburden the more complex goal-directed system and reduce interference in the habit system from processing contingencies of neutral stimuli. Interactions among these systems likely involve inhibitory mechanisms and neuromodulation in the basal ganglia to form a dominant response strategy. Innate traits, training methods, and task demands contribute to the nature of these interactions, which can include incidental learning in non-dominant systems. Addition of these features to reinforcement learning models of decision making may better align theoretical predictions with behavioural and neural

Analysis and control of macro - and microorganisms interactions for missions of different duration

Science.gov (United States)

Somova, L.; Pechurkin, N.

In developing different t pes of life support systems for use in space or extremey environments Earth, researchers should pay attention to the functional state and stability of such systems. Special attention has been given to the interactions between macro- and microorganisms. Microorganisms are considered the most suitable indicators of a system's health and its component links. We can divide all space missions into types by which the behavior of man microbe interactions may be categorized: short missions and long ones. For short missions sanitary and hygiene procedures can be used to control the microflora of open and / or physico -chemical systems of life support. F r more prolonged missions hygieneo provisions may become inadequate and opportunistic infection occur rapidly. In general we should understand that the task of maintaining the heals of human being under conditions of stress is not only a question of sanitation and hygiene, but also a problem of the ecological balance within the habitat.

Utilization and control of ecological interactions in polymicrobial infections and community-based microbial cell factories [version 1; referees: 3 approved

Directory of Open Access Journals (Sweden)

Vinoth Wigneswaran

2016-03-01

Full Text Available Microbial activities are most often shaped by interactions between co-existing microbes within mixed-species communities. Dissection of the molecular mechanisms of species interactions within communities is a central issue in microbial ecology, and our ability to engineer and control microbial communities depends, to a large extent, on our knowledge of these interactions. This review highlights the recent advances regarding molecular characterization of microbe-microbe interactions that modulate community structure, activity, and stability, and aims to illustrate how these findings have helped us reach an engineering-level understanding of microbial communities in relation to both human health and industrial biotechnology.

Exploring Direct 3D Interaction for Full Horizontal Parallax Light Field Displays Using Leap Motion Controller

Directory of Open Access Journals (Sweden)

Vamsi Kiran Adhikarla

2015-04-01

Full Text Available This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

Plasmonic Heterodimers with Binding Site-Dependent Hot Spot for Surface-Enhanced Raman Scattering.

Science.gov (United States)

Tian, Yuanyuan; Shuai, Zhenhua; Shen, Jingjing; Zhang, Lei; Chen, Shufen; Song, Chunyuan; Zhao, Baomin; Fan, Quli; Wang, Lianhui

2018-05-07

A novel plasmonic heterodimer nanostructure with a controllable self-assembled hot spot is fabricated by the conjugation of individual Au@Ag core-shell nanocubes (Au@Ag NCs) and varisized gold nanospheres (GNSs) via the biotin-streptavidin interaction from the ensemble to the single-assembly level. Due to their featured configurations, three types of heterogeneous nanostructures referred to as Vertice, Vicinity, and Middle are proposed and a single hot spot forms between the nanocube and nanosphere, which exhibits distinct diversity in surface plasmon resonance effect. Herein, the calculated surface-enhanced Raman scattering enhancement factors of the three types of heterodimers show a narrow distribution and can be tuned in orders of magnitude by controlling the size of GNSs onto individual Au@Ag NCs. Particularly, the Vertice heterodimer with unique configuration can provide extraordinary enhancement of the electric field for the single hot spot region due to the collaborative interaction of lightning rod effect and interparticle plasmon coupling effect. This established relationship between the architecture and the corresponding optical properties of the heterodimers provides the basis for creating controllable platforms which can be exploited in the applications of plasmonic devices, electronics, and biodetection. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control of the beam-internal target interaction at the nuclotron by means of light radiation

Energy Technology Data Exchange (ETDEWEB)

Artiomov, A.S. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)]. E-mail: artiomov@moonhe.jinr.ru; Anisimov, Yu.S. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Afanasiev, S.V. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Bazilev, S.N. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Zolin, L.S. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Issinsky, I.B. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Kliman, J. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia); Malakhov, A.I. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Matousek, V. [Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia); Morhac, M. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia); Nikitin, V.A. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Nikiforov, A.S. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Nomokonov, P.V. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Pilyar, A.V. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Turzo, I. [Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia)

2005-02-11

The light radiation from various internal targets at the nuclotron can be utilized for the operative control and time optimization of the interaction intensity of the beam. The examples presented in the paper illustrate information about the space characteristics of the circulating beam during one cycle of the accelerator run at the stages of injection, acceleration and during the physical experiments, respectively.

Superparamagnetism and spin-glass like state for the MnFe2O4 nano-particles synthesized by the thermal decomposition method

International Nuclear Information System (INIS)

Gao Ruorui; Zhang Yue; Yu Wei; Xiong Rui; Shi Jing

2012-01-01

MnFe 2 O 4 nano-particles with an average size of about 7 nm were synthesized by the thermal decomposition method. Based on the magnetic hysteresis loops measured at different temperatures the temperature-dependent saturation magnetization (M S ) and coercivity (H C ) are determined. It is shown that above 20 K the temperature-dependence of the M S and H C indicates the magnetic behaviors in the single-domain nano-particles, while below 20 K, the change of the M S and H C indicates the freezing of the spin-glass like state on the surfaces. By measuring the magnetization–temperature (M–T) curves under the zero-field-cooling (ZFC) and field-cooling procedures at different applied fields, superparamagnetism behavior is also studied. Even though in the ZFC M–T curves peaks can be observed below 160 K, superparamagnetism does not appear until the temperature goes above 300 K, which is related with the strong inter-particle interaction. - Highlights: ► MnFe 2 O 4 nano-particles with size of 7 nm were prepared. ► The surface spin-glass like state is frozen below 20 K. ► The peaks in ZFC magnetization–temperature curves are observed below 160 K. ► The inter-particle interaction inhibits the superparamagnetism at room temperature.

Rheological Properties of Automorphic and Semihydromorphic Cryometamorphic Northern Taiga Soils in Northeastern European Russia (Komi Republic)

Science.gov (United States)

Kholopov, Yu. V.; Khaidapova, D. D.; Lapteva, E. M.

2018-04-01

Soil pastes at the water content corresponding to the maximum swelling of samples from different genetic horizons of cryometamorphic soils―surface-gleyic iron-illuvial svetlozem (Folic Albic Stagnosol) and peaty and peat humus-impregnated gleyic svetlozems (Histic Gleyic Stagnosols)―have been studied with an MCR-302 modular rheometer (Anton Paar, Austria). It has been found that the strongest interparticle bonds are formed in the horizons of cryometamorphic soils characterized by high contents of humic substances and organomineral Al-Fe-humus compounds. These are horizons of podzol microprofile (Eg and BHF) in iron-illuvial svetlozem and a humus-impregnated horizon (ELhi,g) in peaty and peat svetlozems. Organomineral Al-Fe-humus compounds, as well as the seasonal freezing of soils, determine the elastic-brittle character of interparticle interactions. The contents of clay fractions, exchangeable bases, and organic and organomineral substances impart viscoelastic properties to these contacts. An enhancement of elastic-brittle properties of soil is observed under the impact of gleying and freezing. The threefold decrease of the structural interaction parameter (∫ Z) when going from automorphic to semihydromorphic conditions indicates a decrease in the resistance of peaty and peat svetlozems to mechanical loads under increasing hydromorphism compared to iron-illuvial svetlozems.

Investigation of the Bose–Einstein condensation based on fractality using fractional mathematics

International Nuclear Information System (INIS)

Şirin, Hüseyin; Ertik, Hüseyin; Büyükkiliç, Fevzi; Demirhan, Doğan

2010-01-01

Although atomic Bose gases are investigated in the dilute gas regime, the physical properties of the Bose–Einstein condensates are affected by interparticle interactions and the fractal nature of the space where the Bose systems are evolving. Theoretical predictions of the traditional Bose–Einstein thermostatistics do not account for the deviations from the experimental results, which are related to internal energy, specific heat, transition temperature, etc. On the other hand, in this study, fractional calculus is introduced where effects of the fractality of space are taken into account. Meanwhile, the order of the fractional derivative α is handled as a measure of the fractality of space. In this content, some improvements which take into account the effects of the fractal nature of the system are made in the standard physical results of the Bose–Einstein condensation phenomena. As an example, for the dilute atomic gas 7 Li, the measured transition temperature of Bose–Einstein condensation could be obtained for the value of α ≈ 0.976, and one could predict that the interparticle interactions have a weak attractive nature consistent with experiment (Bradley et al 1995 Phys. Rev. Lett. 75 1687). Thus, a fractional mathematical theory is established in coherence with experimental results of Bose–Einstein condensation

Key aromatic/hydrophobic amino acids controlling a cross-amyloid peptide interaction versus amyloid self-assembly.

Science.gov (United States)

Bakou, Maria; Hille, Kathleen; Kracklauer, Michael; Spanopoulou, Anna; Frost, Christina V; Malideli, Eleni; Yan, Li-Mei; Caporale, Andrea; Zacharias, Martin; Kapurniotu, Aphrodite

2017-09-01

The interaction of the intrinsically disordered polypeptide islet amyloid polypeptide (IAPP), which is associated with type 2 diabetes (T2D), with the Alzheimer's disease amyloid-β (Aβ) peptide modulates their self-assembly into amyloid fibrils and may link the pathogeneses of these two cell-degenerative diseases. However, the molecular determinants of this interaction remain elusive. Using a systematic alanine scan approach, fluorescence spectroscopy, and other biophysical methods, including heterocomplex pulldown assays, far-UV CD spectroscopy, the thioflavin T binding assay, transmission EM, and molecular dynamics simulations, here we identified single aromatic/hydrophobic residues within the amyloid core IAPP region as hot spots or key residues of its cross-interaction with Aβ40(42) peptide. Importantly, we also find that none of these residues in isolation plays a key role in IAPP self-assembly, whereas simultaneous substitution of four aromatic/hydrophobic residues with Ala dramatically impairs both IAPP self-assembly and hetero-assembly with Aβ40(42). Furthermore, our experiments yielded several novel IAPP analogs, whose sequences are highly similar to that of IAPP but have distinct amyloid self- or cross-interaction potentials. The identified similarities and major differences controlling IAPP cross-peptide interaction with Aβ40(42) versus its amyloid self-assembly offer a molecular basis for understanding the underlying mechanisms. We propose that these insights will aid in designing intervention strategies and novel IAPP analogs for the management of type 2 diabetes, Alzheimer's disease, or other diseases related to IAPP dysfunction or cross-amyloid interactions. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Switches of stimulus tagging frequencies interact with the conflict-driven control of selective attention, but not with inhibitory control.

Science.gov (United States)

Scherbaum, Stefan; Frisch, Simon; Dshemuchadse, Maja

2016-01-01

Selective attention and its adaptation by cognitive control processes are considered a core aspect of goal-directed action. Often, selective attention is studied behaviorally with conflict tasks, but an emerging neuroscientific method for the study of selective attention is EEG frequency tagging. It applies different flicker frequencies to the stimuli of interest eliciting steady state visual evoked potentials (SSVEPs) in the EEG. These oscillating SSVEPs in the EEG allow tracing the allocation of selective attention to each tagged stimulus continuously over time. The present behavioral investigation points to an important caveat of using tagging frequencies: The flicker of stimuli not only produces a useful neuroscientific marker of selective attention, but interacts with the adaptation of selective attention itself. Our results indicate that RT patterns of adaptation after response conflict (so-called conflict adaptation) are reversed when flicker frequencies switch at once. However, this effect of frequency switches is specific to the adaptation by conflict-driven control processes, since we find no effects of frequency switches on inhibitory control processes after no-go trials. We discuss the theoretical implications of this finding and propose precautions that should be taken into account when studying conflict adaptation using frequency tagging in order to control for the described confounds. Copyright © 2015 Elsevier B.V. All rights reserved.

Non-interacting surface solvation and dynamics in protein-protein interactions

NARCIS (Netherlands)

Visscher, Koen M.; Kastritis, Panagiotis L.|info:eu-repo/dai/nl/315886668; Bonvin, Alexandre M J J|info:eu-repo/dai/nl/113691238

2015-01-01

Protein-protein interactions control a plethora of cellular processes, including cell proliferation, differentiation, apoptosis, and signal transduction. Understanding how and why proteins interact will inevitably lead to novel structure-based drug design methods, as well as design of de novo

An efficient method for the creation of tunable optical line traps via control of gradient and scattering forces.

Science.gov (United States)

Tietjen, Gregory T; Kong, Yupeng; Parthasarathy, Raghuveer

2008-07-07

Interparticle interaction energies and other useful physical characteristics can be extracted from the statistical properties of the motion of particles confined by an optical line trap. In practice, however, the potential energy landscape, U(x), imposed by the line provides an extra, and in general unknown, influence on particle dynamics. We describe a new class of line traps in which both the optical gradient and scattering forces acting on a trapped particle are designed to be linear functions of the line coordinate and in which their magnitude can be counterbalanced to yield a flat U(x). These traps are formed using approximate solutions to general relations concerning non-conservative optical forces that have been the subject of recent investigations [Y. Roichman, B. Sun, Y. Roichman, J. Amato-Grill, and D. G. Grier, Phys. Rev. Lett. 100, 013602-4 (2008).]. We implement the lines using holographic optical trapping and measure the forces acting on silica microspheres, demonstrating the tunability of the confining potential energy landscape. Furthermore, we show that our approach efficiently directs available laser power to the trap, in contrast to other methods.

Entropy-driven crystal formation on highly strained substrates

KAUST Repository

Savage, John R.

2013-05-20

In heteroepitaxy, lattice mismatch between the deposited material and the underlying surface strongly affects nucleation and growth processes. The effect of mismatch is well studied in atoms with growth kinetics typically dominated by bond formation with interaction lengths on the order of one lattice spacing. In contrast, less is understood about how mismatch affects crystallization of larger particles, such as globular proteins and nanoparticles, where interparticle interaction energies are often comparable to thermal fluctuations and are short ranged, extending only a fraction of the particle size. Here, using colloidal experiments and simulations, we find particles with short-range attractive interactions form crystals on isotropically strained lattices with spacings significantly larger than the interaction length scale. By measuring the free-energy cost of dimer formation on monolayers of increasing uniaxial strain, we show the underlying mismatched substrate mediates an entropy-driven attractive interaction extending well beyond the interaction length scale. Remarkably, because this interaction arises from thermal fluctuations, lowering temperature causes such substrate-mediated attractive crystals to dissolve. Such counterintuitive results underscore the crucial role of entropy in heteroepitaxy in this technologically important regime. Ultimately, this entropic component of lattice mismatched crystal growth could be used to develop unique methods for heterogeneous nucleation and growth of single crystals for applications ranging from protein crystallization to controlling the assembly of nanoparticles into ordered, functional superstructures. In particular, the construction of substrates with spatially modulated strain profiles would exploit this effect to direct self-assembly, whereby nucleation sites and resulting crystal morphology can be controlled directly through modifications of the substrate.

On-orbit evaluation of the control system/structural mode interactions on OSO-8

Science.gov (United States)

Slafer, L. I.

1980-01-01

The Orbiting Solar Observatory-8 experienced severe structural mode/control loop interaction problems during the spacecraft development. Extensive analytical studies, using the hybrid coordinate modeling approach, and comprehensive ground testing were carried out in order to achieve the system's precision pointing performance requirements. A recent series of flight tests were conducted with the spacecraft in which a wide bandwidth, high resolution telemetry system was utilized to evaluate the on-orbit flexible dynamics characteristics of the vehicle along with the control system performance. This paper describes the results of these tests, reviewing the basic design problem, analytical approach taken, ground test philosophy, and on-orbit testing. Data from the tests was used to determine the primary mode frequency, damping, and servo coupling dynamics for the on-orbit condition. Additionally, the test results have verified analytically predicted differences between the on-orbit and ground test environments. The test results have led to a validation of both the analytical modeling and servo design techniques used during the development of the control system, and also verified the approach taken to vehicle and servo ground testing.

NATO Advanced Study Institute entitled Physics of Plasma-Wall Interactions in Controlled Fusion

CERN Document Server

Behrisch, R; Physics of plasma-wall interactions in controlled fusion

1986-01-01

Controlled thermonuclear fusion is one of the possible candidates for long term energy sources which will be indispensable for our highly technological society. However, the physics and technology of controlled fusion are extremely complex and still require a great deal of research and development before fusion can be a practical energy source. For producing energy via controlled fusion a deuterium-tritium gas has to be heated to temperatures of a few 100 Million °c corres­ ponding to about 10 keV. For net energy gain, this hot plasma has to be confined at a certain density for a certain time One pro­ mising scheme to confine such a plasma is the use of i~tense mag­ netic fields. However, the plasma diffuses out of the confining magnetic surfaces and impinges on the surrounding vessel walls which isolate the plasma from the surrounding air. Because of this plasma wall interaction, particles from the plasma are lost to the walls by implantation and are partially reemitted into the plasma. In addition, wall...

Launch Vehicle Manual Steering with Adaptive Augmenting Control In-flight Evaluations of Adverse Interactions Using a Piloted Aircraft

Science.gov (United States)

Hanson, Curt; Miller, Chris; Wall, John H.; Vanzwieten, Tannen S.; Gilligan, Eric; Orr, Jeb S.

2015-01-01

An adaptive augmenting control algorithm for the Space Launch System has been developed at the Marshall Space Flight Center as part of the launch vehicles baseline flight control system. A prototype version of the SLS flight control software was hosted on a piloted aircraft at the Armstrong Flight Research Center to demonstrate the adaptive controller on a full-scale realistic application in a relevant flight environment. Concerns regarding adverse interactions between the adaptive controller and a proposed manual steering mode were investigated by giving the pilot trajectory deviation cues and pitch rate command authority. Two NASA research pilots flew a total of twenty five constant pitch-rate trajectories using a prototype manual steering mode with and without adaptive control.

Interactive Virtual Cinematography

DEFF Research Database (Denmark)

Burelli, Paolo

is the process of visualising the content of a virtual environment by positioning and animating the virtual camera in the context of interactive applications such as a computer game. Camera placement and animation in games are usually directly controlled by the player or statically predened by designers. Direct...... control of the camera by the player increases the complexity of the interaction and reduces the designer's control on game storytelling. A completely designer-driven camera releases the player from the burden of controlling the point of view, but might generate undesired camera behaviours. Furthermore......, if the content of the game is procedurally generated, the designer might not have the necessary information to dene a priori the camera positions and movements. Automatic camera control aims to dene an abstraction layer that permits to control the camera using high-level and environment-independent rules...

An overview of adaptive model theory: solving the problems of redundancy, resources, and nonlinear interactions in human movement control.

Science.gov (United States)

Neilson, Peter D; Neilson, Megan D

2005-09-01

Adaptive model theory (AMT) is a computational theory that addresses the difficult control problem posed by the musculoskeletal system in interaction with the environment. It proposes that the nervous system creates motor maps and task-dependent synergies to solve the problems of redundancy and limited central resources. These lead to the adaptive formation of task-dependent feedback/feedforward controllers able to generate stable, noninteractive control and render nonlinear interactions unobservable in sensory-motor relationships. AMT offers a unified account of how the nervous system might achieve these solutions by forming internal models. This is presented as the design of a simulator consisting of neural adaptive filters based on cerebellar circuitry. It incorporates a new network module that adaptively models (in real time) nonlinear relationships between inputs with changing and uncertain spectral and amplitude probability density functions as is the case for sensory and motor signals.

Physical adsorption at the nanoscale: Towards controllable scaling of the substrate-adsorbate van der Waals interaction

Science.gov (United States)

Ambrosetti, Alberto; Silvestrelli, Pier Luigi; Tkatchenko, Alexandre

2017-06-01

The Lifshitz-Zaremba-Kohn (LZK) theory is commonly considered as the correct large-distance limit for the van der Waals (vdW) interaction of adsorbates (atoms, molecules, or nanoparticles) with solid substrates. In the standard approximate form, implicitly based on local dielectric functions, the LZK approach predicts universal power laws for vdW interactions depending only on the dimensionality of the interacting objects. However, recent experimental findings are challenging the universality of this theoretical approach at finite distances of relevance for nanoscale assembly. Here, we present a combined analytical and numerical many-body study demonstrating that physical adsorption can be significantly enhanced at the nanoscale. Regardless of the band gap or the nature of the adsorbate specie, we find deviations from conventional LZK power laws that extend to separation distances of up to 10-20 nm. Comparison with recent experimental observations of ultra-long-ranged vdW interactions in the delamination of graphene from a silicon substrate reveals qualitative agreement with the present theory. The sensitivity of vdW interactions to the substrate response and to the adsorbate characteristic excitation frequency also suggests that adsorption strength can be effectively tuned in experiments, paving the way to an improved control of physical adsorption at the nanoscale.

Detection and Control of Spin-Orbit Interactions in a GaAs Hole Quantum Point Contact

Science.gov (United States)

Srinivasan, A.; Miserev, D. S.; Hudson, K. L.; Klochan, O.; Muraki, K.; Hirayama, Y.; Reuter, D.; Wieck, A. D.; Sushkov, O. P.; Hamilton, A. R.

2017-04-01

We investigate the relationship between the Zeeman interaction and the inversion-asymmetry-induced spin-orbit interactions (Rashba and Dresselhaus SOIs) in GaAs hole quantum point contacts. The presence of a strong SOI results in the crossing and anticrossing of adjacent spin-split hole subbands in a magnetic field. We demonstrate theoretically and experimentally that the anticrossing energy gap depends on the interplay between the SOI terms and the highly anisotropic hole g tensor and that this interplay can be tuned by selecting the crystal axis along which the current and magnetic field are aligned. Our results constitute the independent detection and control of the Dresselhaus and Rashba SOIs in hole systems, which could be of importance for spintronics and quantum information applications.

Opportunities, Rational Choice, and Self-Control: On the Interaction of Person and Situation in a General Theory of Crime

Science.gov (United States)

Seipel, Christian; Eifler, Stefanie

2010-01-01

In this article, deviant action is analyzed on the basis of ideas derived from Gottfredson and Hirschi's self-control theory. Presumedly, self-control in interaction with opportunities can explain deviant action. This assumption is elaborated using the concept of high- and low-cost situations from rational choice theory. From this point of view,…

Interaction with control agencies

International Nuclear Information System (INIS)

Robertson, J.S.

1983-01-01

In addition to the licensing and inspections that apply to all departments in a hospital, certain special requirements apply to the uses of radioactive materials in diagnosis, therapy, and research involving human subjects. In part this chapter discusses these special requirements and how they can be met. Some official sources of information pertinent to the measurement and safe handling of radioactive materials also are mentioned. Aspects of the legal control of the manufacture and transportation of radioactive substances that usually involve hospitals only indirectly will not be covered comprehensively. However, if physicians, clinics, or hospitals develop programs under which they supply radioactive substances to other individuals or institutions, they become subject to further controls, rules, and regulations concerning the manufacture and transportation of radioactive substances. Regulation of drug production and testing is the responsibility of the U.S. Food and Drug Administration (FDA). Shipment of radioactive materials is regulated by the U.S. Department of Transportation

Semi-quantum treatment of interactions inside a plasma; Traitement semi-quantique des interactions dans un plasma

Energy Technology Data Exchange (ETDEWEB)

Feix, M [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Laboratoire Central de l' Armement, 94 - Arcueil (France)

1960-07-01

An interesting length in quantum plasma theory is the mean de Broglie wavelength of particles {lambda}-bar = {Dirac_h} < mv > {alpha}{Dirac_h} (mKT){sup 1/2}. A plasma shows both individual and collective behaviour, and we see that the individual behaviour is correctly described by a simple cutoff of the Coulomb interaction for distance shorter than {lambda}-bar. For studying the collective aspect we introduce an artificial potential (e{sup 2}/r)(1 - exp(-{gamma}r)) with {gamma} {alpha} {lambda}-bar{sup -1} instead of the Coulomb potential, and apply Yvon's method for the calculation of correlations between particle positions. We connect this point of view with that of Bohm and Pines (build-up with Fourier components of the particle density) and again find important quantum effects at temperatures KT below the 'plasmon energy' {Dirac_h}{omega}{sub p}. Comparison between Debye length, interparticle distance, and {lambda}-bar, shows a classification of plasma zones in a density vs. temperature diagram. (author) [French] Une longueur importante dans la theorie quantique des plasmas est la longueur d'onde de de Broglie moyenne des particules {lambda}-bar = {Dirac_h} < mv > {alpha}{Dirac_h} (mKT){sup 1/2}. Les plasmas peuvent presenter a la fois et un aspect collectif et un aspect individuel, et on voit que le comportement des plasmas principalement individuels est donne exactement par une simple annulation de l'interaction coulombienne pour les distances inferieures {lambda}-bar. Pour l'etude de l'aspect collectif, on introduit un potentiel artificiel (e{sup 2}/r)(1 - exp(-{gamma}r)) avec {gamma} {alpha} {lambda}-bar{sup -1} au lieu du potentiel coulombien, et l'on applique le methode de Yvon pour le calcul des correlations entre les positions des particules. On fait un rapprochement de ce point de vue avec celui de Bohn et Pines (un accroissement de la densite particulaire avec les composantes de Fourier) et on trouve de nouveau des effets quantiques importants a des

Interacting cannabinoid and opioid receptors in the nucleus accumbens core control adolescent social play

Directory of Open Access Journals (Sweden)

Antonia Manduca

2016-11-01

Full Text Available Social play behavior is a highly rewarding, developmentally important form of social interaction in young mammals. However, its neurobiological underpinnings remain incompletely understood. Previous work has suggested that opioid and endocannabinoid neurotransmission interact in the modulation of social play. Therefore, we combined behavioral, pharmacological, electrophysiological and genetic approaches to elucidate the role of the endocannabinoid 2-arachidonoylglycerol (2-AG in social play, and how cannabinoid and opioid neurotransmission interact to control social behavior in adolescent rodents. Systemic administration of the 2-AG hydrolysis inhibitor JZL184 or the opioid receptor agonist morphine increased social play behavior in adolescent rats. These effects were blocked by systemic pretreatment with either CB1 cannabinoid receptor (CB1R or mu-opioid receptor (MOR antagonists. The social play-enhancing effects of systemic morphine or JZL184 treatment were also prevented by direct infusion of the CB1R antagonist SR141716 and the MOR antagonist naloxone into the nucleus accumbens core (NAcC. Searching for synaptic correlates of these effects in adolescent NAcC excitatory synapses, we observed that CB1R antagonism blocked the effect of the MOR agonist DAMGO and, conversely, that naloxone reduced the effect of a cannabinoid agonist. These results were recapitulated in mice, and completely abolished in CB1R and MOR knockout mice, suggesting that the functional interaction between CB1R and MOR in the NAcC in the modulation of mediates social behavior is widespread in rodents. The data shed new light on the mechanism by which endocannabinoid lipids and opioid peptides interact to orchestrate rodent socioemotional behaviors.

Use of 1–4 interaction scaling factors to control the conformational equilibrium between α-helix and β-strand

International Nuclear Information System (INIS)

Pang, Yuan-Ping

2015-01-01

Highlights: • 1–4 interaction scaling factors are used to adjust conformational energy. • This article reports the effects of these factors on protein conformations. • Reducing these factors changes a helix to a strand in molecular dynamics simulation. • Increasing these factors causes the reverse conformational change. • These factors control the conformational equilibrium between helix and strand. - Abstract: 1–4 interaction scaling factors are used in AMBER forcefields to reduce the exaggeration of short-range repulsion caused by the 6–12 Lennard-Jones potential and a nonpolarizable charge model and to obtain better agreements of small-molecule conformational energies with experimental data. However, the effects of these scaling factors on protein secondary structure conformations have not been investigated until now. This article reports the finding that the 1–4 interactions among the protein backbone atoms separated by three consecutive covalent bonds are more repulsive in the α-helix conformation than in two β-strand conformations. Therefore, the 1–4 interaction scaling factors of protein backbone torsions ϕ and ψ control the conformational equilibrium between α-helix and β-strand. Molecular dynamics simulations confirm that reducing the ϕ and ψ scaling factors readily converts the α-helix conformation of AcO-(AAQAA) 3 -NH 2 to a β-strand conformation, and the reverse occurs when these scaling factors are increased. These results suggest that the ϕ and ψ scaling factors can be used to generate the α-helix or β-strand conformation in situ and to control the propensities of a forcefield for adopting secondary structure elements

Superparamagnetism and coercivity in HCP-Co nanoparticles dispersed in silica matrix

International Nuclear Information System (INIS)

Julian Fernandez, C. de; Mattei, G.; Sangregorio, C.; Battaglin, C.; Gatteschi, D.; Mazzoldi, P.

2004-01-01

The magnetic properties of Co HCP nanoparticles dispersed in a silica matrix with sizes between 2±0.7 and 5±2.2 nm were investigated. The temperature dependence of zero-field cooled and field cooled magnetizations and of the coercive field were analyzed considering the thermal activated demagnetization process. Enhanced anisotropy was observed for the 2 nm nanoparticles, while the demagnetization process of the larger ones is dominated by interparticle interactions

Density and surface tension of high-temperature stratifying mixtures of alkali metal bromides and lithium fluoride

International Nuclear Information System (INIS)

Rukavishnikova, I.V.; Lokett, V.N.; Burukhin, A.S.; Stepanov, V.P.

2006-01-01

The density and interphase tension of molten mixtures of lithium fluoride with potassium, rubidium, and cesium bromides were measured over the temperature range 1120-1320 K in the region of limited mutual solubility by the hydrostatic weighing and meniscus weight methods. The dependences of properties on the size ratio between the mixed ions were determined. The critical order parameters for systems with the predominantly ionic character of interparticle interactions were estimated [ru

RLE (Research Laboratory of Electronics) Progress Report Number 125.

Science.gov (United States)

1983-01-01

gate and inverter. POLARIZER 4L® Ic ’ / LOUTPUT TRUTH TABLE Figure 7-1 We have demonstrated operation of the device fabricated in LiNbO3 as a...Scattering," J. Phys. Chem. 87, 1653 (1983). Bendedouch, D. and S.-H. Chen, "Structure and Interparticle Interactions of Bovine Serum Albumin in Solution...were drawn. Conventional Bayesian estimation methods, when applied to these problems, would typically require a numerically unpleasant multi

Magnetic properties of iron catalyst particles in HiPco single wall carbon nanotubes

Czech Academy of Sciences Publication Activity Database

Bittová, Barbara; Poltierová Vejpravová, Jana; Kalbáč, Martin; Burianová, Simona; Mantlíková, A.; Daniš, S.; Doyle, S.

2011-01-01

Roč. 115, č. 35 (2011), s. 17303-17309 ISSN 1932-7447 R&D Projects: GA ČR GAP204/10/1677 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z40400503 Keywords : metal catalyst particles * carbon nanotubes * superparamagnet * core - shell model * inter-particle interactions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.805, year: 2011 http://pubs.acs.org/doi/abs/10.1021/jp203365g

Magnetic Properties of Nanometer-sized Crystalline and Amorphous Particles

DEFF Research Database (Denmark)

Mørup, Steen; Bødker, Franz; Hansen, Mikkel Fougt

1997-01-01

Amorphous transition metal-metalloid alloy particles can be prepared by chemical preparation techniques. We discuss the preparation of transition metal-boron and iron-carbon particles and their magnetic properties. Nanometer-sized particles of both crystalline and amorphous magnetic materials...... are superparamagnetic at finite temperatures. The temperature dependence of the superparamagnetic relaxation time and the influence of inter-particle interactions is discussed. Finally, some examples of studies of surface magnetization of alpha-Fe particles are presented....

A discussion of techniques used in defining the Interactive Measurement Evaluation and Control System at Rocky Flats

International Nuclear Information System (INIS)

Greer, B.K.; Hunt, V.; Schweitzer, M.F.

1983-01-01

This paper describes both the general methodology used to study the current needs for a measurement control and evaluation system at Rocky Flats Plant and the recommendations for implementation into the Interactive Measurement Evaluation and Control System (IMECS). The study resulted in a clear assessment of the current system and recommendations for the system which will be its replacement. To arrive at the recommendations, the authors used a formal analysis approach that is based on an in-depth study of the measurement evaluation and control problems and user needs. The problems and needs were defined by interviews with present and potential users of this kind of system throughout the nuclear industry. Some of the recommendations are to provide: timely sample measurement feedback; representative measurement error estimates; a history data base of sample measurements To meet the user needs, the new system will: be interactive with user selection menus; use standards which cover the range of application; facilitate historical analysis of sample data and bookkeeping. The implementation of this program is projected to be more cost effective than the current program. Also included are the authors' recommendations to those involved in the design of a system of similar large magnitude

Empowerment of disability benefit claimants through an interactive website: design of a randomized controlled trial.

Science.gov (United States)

Samoocha, David; Bruinvels, David J; Anema, Johannes R; Steenbeek, Romy; van der Beek, Allard J

2009-05-10

Individuals claiming a disability benefit after long-term sickness absence, have to undergo medical disability assessments. These assessments, often carried out by specialized physicians, can be complicated by wrong expectations or defensive attitudes of disability benefit claimants. It is hypothesized that empowerment of these claimants will enhance the physician-patient relationship by shifting claimants from a passive role to a more active and constructive role during disability assessments. Furthermore, empowerment of claimants may lead to a more realistic expectation and acceptance of the assessment outcome among claimants and may lead to a more accurate assessment by the physician. In a two-armed randomized controlled trial (RCT), 230 claimants will be randomized to either the intervention or control group. For the intervention group, an interactive website was designed http://www.wiagesprek.nl using an Intervention Mapping procedure. This website was tested during a pilot study among 51 claimants. The final version of the website consists of five interactive modules, in which claimants will be prepared and empowered step-by-step, prior to their upcoming disability assessment. Other website components are a forum, a personal health record, a personal diary, and information on disability assessment procedures, return to work, and coping with disease and work disability. Subjects from the control group will be directed to a website with commonly available information only. Approximately two weeks prior to their disability assessment, disability claimants will be recruited through the Dutch Workers Insurance Authority (UWV). Outcomes will be assessed at five occasions: directly after recruitment (baseline), prior to disability assessment, directly after disability assessment as well as 6 and 16 weeks after the assessment. The study's primary outcome is empowerment, measured with the Vrijbaan questionnaire. Secondary outcomes include claimants' satisfaction

Viscosity calculations at molecular dynamics simulations

International Nuclear Information System (INIS)

Kirova, E M; Norman, G E

2015-01-01

Viscosity and diffusion are chosen as an example to demonstrate the universality of diagnostics methods in the molecular dynamics method. To emphasize the universality, three diverse systems are investigated, which differ from each other drastically: liquids with embedded atom method and pairwise interatomic interaction potentials and dusty plasma with a unique multiparametric interparticle interaction potential. Both the Einstein-Helfand and Green-Kubo relations are used. Such a particular process as glass transition is analysed at the simulation of the aluminium melt. The effect of the dust particle charge fluctuation is considered. The results are compared with the experimental data. (paper)

Evaluation of Early Ground Control Station Configurations for Interacting with a UAS Traffic Management (UTM) System

Science.gov (United States)

Dao, Arik-Quang V.; Martin, Lynne; Mohlenbrink, Christoph; Bienert, Nancy; Wolte, Cynthia; Gomez, Ashley; Claudatos, Lauren; Mercer, Joey

2017-01-01

The purpose of this paper is to report on a human factors evaluation of ground control station design concepts for interacting with an unmanned traffic management system. The data collected for this paper comes from recent field tests for NASA's Unmanned Traffic Management (UTM) project, and covers the following topics; workload, situation awareness, as well as flight crew communication, coordination, and procedures. The goal of this evaluation was to determine if the various software implementations for interacting with the UTM system can be described and classified into design concepts to provide guidance for the development of future UTM interfaces. We begin with a brief description of NASA's UTM project, followed by a description of the test range configuration related to a second development phase. We identified (post hoc) two classes in which the ground control stations could be grouped. This grouping was based on level of display integration. The analysis was exploratory and informal. It was conducted to compare ground stations across those two classes and against the aforementioned topics. Herein, we discuss the results.

Dark-dark-soliton dynamics in two density-coupled Bose-Einstein condensates

Science.gov (United States)

Morera, I.; Mateo, A. Muñoz; Polls, A.; Juliá-Díaz, B.

2018-04-01

We study the one-dimensional dynamics of dark-dark solitons in the miscible regime of two density-coupled Bose-Einstein condensates having repulsive interparticle interactions within each condensate (g >0 ). By using an adiabatic perturbation theory in the parameter g12/g , we show that, contrary to the case of two solitons in scalar condensates, the interactions between solitons are attractive when the interparticle interactions between condensates are repulsive g12>0 . As a result, the relative motion of dark solitons with equal chemical potential μ is well approximated by harmonic oscillations of angular frequency wr=(μ /ℏ ) √{(8 /15 ) g12/g } . We also show that, in finite systems, the resonance of this anomalous excitation mode with the spin-density mode of lowest energy gives rise to alternating dynamical instability and stability fringes as a function of the perturbative parameter. In the presence of harmonic trapping (with angular frequency Ω ) the solitons are driven by the superposition of two harmonic motions at a frequency given by w2=(Ω/√{2 }) 2+wr2 . When g12<0 , these two oscillators compete to give rise to an overall effective potential that can be either single well or double well through a pitchfork bifurcation. All our theoretical results are compared with numerical solutions of the Gross-Pitaevskii equation for the dynamics and the Bogoliubov equations for the linear stability. A good agreement is found between them.

Interactive effects of trait and state affect on top-down control of attention.

Science.gov (United States)

Hur, Juyoen; Miller, Gregory A; McDavitt, Jenika R B; Spielberg, Jeffrey M; Crocker, Laura D; Infantolino, Zachary P; Towers, David N; Warren, Stacie L; Heller, Wendy

2015-08-01

Few studies have investigated how attentional control is affected by transient affective states while taking individual differences in affective traits into consideration. In this study, participants completed a color-word Stroop task immediately after undergoing a positive, neutral or negative affective context manipulation (ACM). Behavioral performance was unaffected by any ACM considered in isolation. For individuals high in trait negative affect (NA), performance was impaired by the negative but not the positive or neutral ACM. Neuroimaging results indicate that activity in primarily top-down control regions of the brain (inferior frontal gyrus and dorsal anterior cingulate cortex) was suppressed in the presence of emotional arousal (both negative and positive ACMs). This effect appears to have been exacerbated or offset by co-occurring activity in other top-down control regions (parietal) and emotion processing regions (orbitofrontal cortex, amygdala and nucleus accumbens) as a function of the valence of state affect (positive or negative) and trait affect (trait NA or trait PA). Neuroimaging results are consistent with behavioral findings. In combination, they indicate both additive and interactive influences of trait and state affect on top-down control of attention. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

A virtual control room with an embedded, interactive nuclear reactor simulator

International Nuclear Information System (INIS)

Markidis, S.; Rizwan, U.

2006-01-01

The use of virtual nuclear control room can be an effective and powerful tool for training personnel working in the nuclear power plants. Operators could experience and simulate the functioning of the plant, even in critical situations, without being in a real power plant or running any risk. 3D models can be exported to Virtual Reality formats and then displayed in the Virtual Reality environment providing an immersive 3D experience. However, two major limitations of this approach are that 3D models exhibit static textures, and they are not fully interactive and therefore cannot be used effectively in training personnel. In this paper we first describe a possible solution for embedding the output of a computer application in a 3D virtual scene, coupling real-world applications and VR systems. The VR system reported here grabs the output of an application running on an X server; creates a texture with the output and then displays it on a screen or a wall in the virtual reality environment. We then propose a simple model for providing interaction between the user in the VR system and the running simulator. This approach is based on the use of internet-based application that can be commanded by a laptop or tablet-pc added to the virtual environment. (authors)

Interactive Controls Analysis (INCA)

Science.gov (United States)

Bauer, Frank H.

1989-01-01

Version 3.12 of INCA provides user-friendly environment for design and analysis of linear control systems. System configuration and parameters easily adjusted, enabling INCA user to create compensation networks and perform sensitivity analysis in convenient manner. Full complement of graphical routines makes output easy to understand. Written in Pascal and FORTRAN.

The Long-Term Effectiveness of the Family Check-up on Peer Preference: Parent-Child Interaction and Child Effortful Control as Sequential Mediators.

Science.gov (United States)

Chang, Hyein; Shaw, Daniel S; Shelleby, Elizabeth C; Dishion, Thomas J; Wilson, Melvin N

2017-05-01

We examined the longitudinal effects of the Family Check-Up (FCU) intervention beginning in toddlerhood on children's peer preference at school-age. Specifically, a sequential mediational model was proposed in which the FCU was hypothesized to promote peer preference (i.e., higher acceptance and lower rejection by peers) in middle childhood through its positive effects on parent-child interaction and child effortful control in early childhood. Participants were 731 low-income families (49 % female). Qualities of parent-child interaction were observed during structured activities at 2 to 5 years, child effortful control was assessed using behavioral tasks at 5 years, and peer acceptance and rejection were rated by teachers at 7.5 to 10.5 years. Results indicated that the FCU indirectly predicted peer preference by sequentially improving parent-child interaction and child effortful control. The findings are discussed with respect to implications for understanding mechanisms by which early parenting-focused programs may enhance child functioning across time and context.

An Abstract Interaction Concept for Designing Interaction Behaviour of Service Compositions

NARCIS (Netherlands)

Dirgahayu, T.; Quartel, Dick; van Sinderen, Marten J.; Mertins, Kai; Ruggaber, Rainer; Popplewell, Keith; Xu, Xiaofei

2008-01-01

In a service composition, interaction behaviour specifies an information exchange protocol that must be complied with in order to guarantee interoperability between services. Interaction behaviour can be designed using a top-down design approach utilising high abstraction levels to control its

2nd Symposium on Fluid-Structure-Sound Interactions and Control

CERN Document Server

Liu, Yang; Huang, Lixi; Hodges, Dewey

2014-01-01

With rapid economic and industrial development in China, India and elsewhere, fluid-related structural vibration and noise problems are widely encountered in many fields, just as they are in the more developed parts of the world, causing increasingly grievous concerns. Turbulence clearly has a significant impact on many such problems. On the other hand, new opportunities are emerging with the advent of various new technologies, such as signal processing, flow visualization and diagnostics, new functional materials, sensors and actuators, etc. These have revitalized interdisciplinary research activities, and it is in this context that the 2nd symposium on fluid-structure-sound interactions and control (FSSIC) was organized. Held in Hong Kong (May 20-21, 2013) and Macau (May 22-23, 2013), the meeting brought together scientists and engineers working in all related branches from both East and West and provided them with a forum to exchange and share the latest progress, ideas and advances and to chart the fronti...

Factors controlling the mode of rift interaction in brittle-ductile coupled systems: A 3D numerical study

NARCIS (Netherlands)

Allken, V.; Huismans, R.S.; Thieulot, C.

2012-01-01

The way individual faults and rift segments link up is a fundamental aspect of lithosphere extension and continental break-up. Little is known however about the factors that control the selection of the different modes of rift interaction observed in nature. Here we use state-of-the-art large

Interaction between demand-control and social support in the occurrence of common mental disorders.

Science.gov (United States)

Mattos, Amália Ivine Santana; Araújo, Tânia Maria de; Almeida, Maura Maria Guimarães de

2017-05-15

To analyze the interaction between the psychosocial aspects of work and the occurrence of common mental disorders among health workers. This is a cross-sectional study conducted with a representative sample of workers of the primary health care of five municipalities of the State of Bahia, Brazil, in 2012. The variable of outcome were the common mental disorders evaluated by the SRQ-20, and the variables of exposure were high demand (high psychological demand and low control over the work) and low social support in the workplace. Interaction was checked by the deviation of the additivity of the effects for the factors studied from the calculation of excess risk from interaction, proportion of cases attributed to interaction, and the synergy index. The global prevalence of common mental disorders was 21%. The group of combined exposure has shown higher magnitude (high demand and low social support), reaching 28% when compared to the 17% in the situation of no exposure (low demand and high social support). The results strengthen the hypothesis of interaction between the factors investigated, directing to the synergy of the effects. Analisar a interação entre aspectos psicossociais do trabalho e a ocorrência de transtornos mentais comuns entre trabalhadores da saúde. Estudo transversal conduzido em amostra representativa de trabalhadores da atenção básica de cinco municípios da Bahia em 2012. As variáveis desfecho foram os transtornos mentais comuns avaliados pelo SRQ-20, as de exposição foram a alta exigência (alta demanda psicológica e baixo controle sobre o próprio trabalho) e o baixo apoio social no trabalho. A interação foi verificada pelo afastamento da aditividade dos efeitos para fatores estudados a partir do cálculo do excesso de risco devido à interação, proporção de casos atribuída à interação e índice de sinergia. A prevalência global de transtornos mentais comuns foi de 21%. Apresentou maior magnitude no grupo de exposi

Oxygen-enabled control of Dzyaloshinskii-Moriya Interaction in ultra-thin magnetic films

KAUST Repository

Belabbes, Abderrezak

2016-04-22

The search for chiral magnetic textures in systems lacking spatial inversion symmetry has attracted a massive amount of interest in the recent years with the real space observation of novel exotic magnetic phases such as skyrmions lattices, but also domain walls and spin spirals with a defined chirality. The electrical control of these textures offers thrilling perspectives in terms of fast and robust ultrahigh density data manipulation. A powerful ingredient commonly used to stabilize chiral magnetic states is the so-called Dzyaloshinskii-Moriya interaction (DMI) arising from spin-orbit coupling in inversion asymmetric magnets. Such a large antisymmetric exchange has been obtained at interfaces between heavy metals and transition metal ferromagnets, resulting in spin spirals and nanoskyrmion lattices. Here, using relativistic first-principles calculations, we demonstrate that the magnitude and sign of DMI can be entirely controlled by tuning the oxygen coverage of the magnetic film, therefore enabling the smart design of chiral magnetism in ultra-thin films. We anticipate that these results extend to other electronegative ions and suggest the possibility of electrical tuning of exotic magnetic phases.

Interactive motion-controlled games in the neurorehabilitation of adult post-stroke patients

Directory of Open Access Journals (Sweden)

Emilia Mikołajewska

2015-08-01

Emilia Mikołajewska Rehabilitation Clinic Military Clinical Hospital No. 10 and Polyclinic Bydgoszcz, Poland e-mail: e.mikolajewska@wp.pl, emiliam@cm.umk.pl www: http://emikolajewska.netstrefa.eu   Keywords: neurorehabilitation; physiotherapy; stroke; neurological deficit; therapeutic game.   Abstract   Despite efforts of scientists and clinicians stroke still constitutes one of the major causes of disability worldwide. Motion-controlled video games become increasingly common adjunct to the traditional physical therapy. Such games are usually available, low-cost, fun, and functional ways to increase everyday treatment possibilities, both in hospital, ambulatory and home settings. Research and scientific publications concerning this issue are still rare. Assessment how interactive motion-controlled games can be incorporated into current guidelines of the eclectic approach within neurorehabilitation of adult post-stroke survivors is key issue within contemporary neurorehabilitation of adults. Complementary use of such games may constitute another breakthrough both in in-patient and out-patient rehabilitation and care. This review aims at potential of aforementioned solutions and modalities for the rehabilitation of function in cases of stroke.

Exposure to sennoside-digoxin interaction and risk of digoxin toxicity: a population-based nested case-control study.

Science.gov (United States)

Wang, Meng-Ting; Li, I-Hsun; Lee, Wan-Ju; Huang, Tien-Yu; Leu, Hsin-Bang; Chan, Agnes L F

2011-11-01

Digoxin is an important medication for heart failure (HF) patients and sennosides are widely used to treat constipation. Recently, safety concerns have been raised about a possible interaction between sennosides and digoxin, an issue that has not been studied empirically. This study therefore aimed to evaluate whether exposure to sennoside-digoxin interaction is associated with an increased risk of digoxin toxicity. This was a population-based nested case-control study that analysed data obtained from the Taiwan National Health Insurance Research Database between 1 January 2001 and 31 December 2004. All HF patients treated with digoxin for the first time were included as the study cohort. Of these, cases were identified as subjects hospitalized for digoxin toxicity (International Classification of Diseases, Ninth Revision, Clinical Modification, ICD-9-CM 972.1), and matched to randomly selected controls. Use of sennosides was compared between the two groups. Odds ratios (ORs) were employed to quantify the risk associated with exposure to sennoside-digoxin interaction by conditional logistic regression. The study cohort comprised 222,527 HF patients, of whom 524 were identified as cases and 2,502 as matched controls. Use of sennosides during the 14 days preceding the index date was found to be associated with a 1.61-fold increased risk of digoxin toxicity [95% confidence interval (CI) = 1.15, 2.25]. Additionally, a greater risk was observed for sennosides prescribed at an average daily dose ≥ 24 mg (adjusted OR = 1.93; 95% CI = 1.27, 2.94). The combined use of sennosides and digoxin was found to be associated with a modest increased risk of digoxin toxicity in HF patients.

A discrete element model for the influence of surfactants on sedimentation characteristics of magnetorheological fluids

Science.gov (United States)

Son, Kwon Joong

2018-02-01

Hindering particle agglomeration and re-dispersion processes, gravitational sedimentation of suspended particles in magnetorheological (MR) fluids causes inferior performance and controllability of MR fluids in response to a user-specified magnetic field. Thus, suspension stability is one of the principal factors to be considered in synthesizing MR fluids. However, only a few computational studies have been reported so far on the sedimentation characteristics of suspended particles under gravity. In this paper, the settling dynamics of paramagnetic particles suspended in MR fluids was investigated via discrete element method (DEM) simulations. This work focuses particularly on developing accurate fluid-particle and particle-particle interaction models which can account for the influence of stabilizing surfactants on the MR fluid sedimentation. Effect of the stabilizing surfactants on interparticle interactions was incorporated into the derivation of a reliable contact-impact model for DEM computation. Also, the influence of the stabilizing additives on fluid-particle interactions was considered by incorporating Stokes drag with shape and wall correction factors into DEM formulation. The results of simulations performed for model validation purposes showed a good agreement with the published sedimentation measurement data in terms of an initial sedimentation velocity and a final sedimentation ratio.

Use of 1–4 interaction scaling factors to control the conformational equilibrium between α-helix and β-strand

Energy Technology Data Exchange (ETDEWEB)

Pang, Yuan-Ping, E-mail: pang@mayo.edu

2015-02-06

Highlights: • 1–4 interaction scaling factors are used to adjust conformational energy. • This article reports the effects of these factors on protein conformations. • Reducing these factors changes a helix to a strand in molecular dynamics simulation. • Increasing these factors causes the reverse conformational change. • These factors control the conformational equilibrium between helix and strand. - Abstract: 1–4 interaction scaling factors are used in AMBER forcefields to reduce the exaggeration of short-range repulsion caused by the 6–12 Lennard-Jones potential and a nonpolarizable charge model and to obtain better agreements of small-molecule conformational energies with experimental data. However, the effects of these scaling factors on protein secondary structure conformations have not been investigated until now. This article reports the finding that the 1–4 interactions among the protein backbone atoms separated by three consecutive covalent bonds are more repulsive in the α-helix conformation than in two β-strand conformations. Therefore, the 1–4 interaction scaling factors of protein backbone torsions ϕ and ψ control the conformational equilibrium between α-helix and β-strand. Molecular dynamics simulations confirm that reducing the ϕ and ψ scaling factors readily converts the α-helix conformation of AcO-(AAQAA){sub 3}-NH{sub 2} to a β-strand conformation, and the reverse occurs when these scaling factors are increased. These results suggest that the ϕ and ψ scaling factors can be used to generate the α-helix or β-strand conformation in situ and to control the propensities of a forcefield for adopting secondary structure elements.

A unique set of SH3-SH3 interactions controls IB1 homodimerization

DEFF Research Database (Denmark)

Kristensen, Ole; Guenat, Sylvie; Dar, Imran

2006-01-01

Islet-brain 1 (IB1 or JIP-1) is a scaffold protein that interacts with components of the c-Jun N-terminal kinase (JNK) signal-transduction pathway. IB1 is expressed at high levels in neurons and in pancreatic beta-cells, where it controls expression of several insulin-secretory components...... reduces IB1-dependent basal JNK activity in 293T cells. Impaired dimerization also results in a reduction in glucose transporter type 2 expression and in glucose-dependent insulin secretion in pancreatic beta-cells. Taken together, these results indicate that IB1 homodimerization through its SH3 domain...

A molecular dynamics study of the structure and inter-particle interactions of polyethylene glycol-conjugated PAMAM dendrimers

OpenAIRE

Lee, Hwankyu; Larson, Ronald G.

2009-01-01

We performed molecular dynamics (MD) simulations of one or two copies of polyethylene glycol of molecular weight 550 (PEG550) and 5000 (PEG5000) Daltons, conjugated to generation 3 (G3) to 5 (G5) polyamidoamine (PAMAM) dendrimers with explicit water using a coarse-grained model. We found the radii of gyration of these dendrimer-PEG molecules to be close to those measured in experiments by Hedden and Bauer (Macromolecules 2003, 36, 1829). Densely grafted PEG ligands (>50% of the dendrimer surf...

Surface modified superparamagnetic nanoparticles: Interaction with fibroblasts in primary cell culture

Energy Technology Data Exchange (ETDEWEB)

Chapa Gonzalez, Christian; Roacho Pérez, Jorge A.; Martínez Pérez, Carlos A.; Olivas Armendáriz, Imelda [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua, México (Mexico); Jimenez Vega, Florinda [Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Anillo envolvente del PRONAF y Estocolmo, C.P. 32320 Cd. Juárez, Chihuahua, México (Mexico); Castrejon Parga, Karen Y. [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua, México (Mexico); Garcia Casillas, Perla E., E-mail: pegarcia@uacj.mx [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua, México (Mexico)

2014-12-05

Highlights: • An inorganic layer before an organic material shell onto MNPs improves cell viability. • The coating type and the concentration of nanoparticles directly affect cell viability. • Modified magnetite nanoparticles with organic and inorganic materials was developed. - Abstract: The development of a variety of medical applications such as drug delivery, cell labeling, and medical imaging have been possible owing to the unique features exhibited by magnetic nanoparticles. Nanoparticle–cell interaction is related to the surface aspects of nanoparticle, which may be described based on their chemistry or inorganic/organic characteristics. The coating on particle surface reduces the inter-particle interactions and provides properties such as biocompatibility. Among the coating materials used for nanoparticles employed in biomedical applications, oleic acid is one of the most utilized due to its biocompatibility. However, a major drawback with this naturally occurring fatty acid is that it is easily oxidized by cells and this reduces their performance in biomedical applications. In order to avoid the direct contact of the cell with the magnetite particle, coating with an inorganic material prior to the oleic acid shell would be effective. This would retard the magnetite dissociation thereby improve the cell viability. Here we report our investigation on the effect of surface modified magnetite nanoparticles (MNPs) on the cell viability using primary cultures incubated with those particles. We prepared magnetite nanoparticles by chemical co-precipitation method; nanoparticle surface was first modified by silanol condensation followed by chemisorption of oleic acid. All nanostructures have a particle size less than 100 nm, depending on the material coating and superparamagnetic behavior. The saturated magnetizations (M{sub s}) of the magnetite samples coated with oleic acid (MAO; 49.15 emu/g) and double shell silica-oleic acid (MSAO; 46.16 emu/g) are

FQC Dashboard: integrates FastQC results into a web-based, interactive, and extensible FASTQ quality control tool

Energy Technology Data Exchange (ETDEWEB)

Brown, Joseph; Pirrung, Meg; McCue, Lee Ann

2017-06-09

FQC is software that facilitates large-scale quality control of FASTQ files by carrying out a QC protocol, parsing results, and aggregating quality metrics within and across experiments into an interactive dashboard. The dashboard utilizes human-readable configuration files to manipulate the pages and tabs, and is extensible with CSV data.

Developing a Tool Point Control Scheme for a Hydraulic Crane Using Interactive Real-time Dynamic Simulation

DEFF Research Database (Denmark)

Pedersen, Mikkel Melters; Hansen, Michael Rygaard; Ballebye, Morten

2010-01-01

This paper describes the implementation of an interactive real-time dynamic simulation model of a hydraulic crane. The user input to the model is given continuously via joystick and output is presented continuously in a 3D animation. Using this simulation model, a tool point control scheme...... is developed for the specific crane, considering the saturation phenomena of the system and practical implementation....

Possible applications of the LEAP motion controller for more interactive simulated experiments in augmented or virtual reality

Science.gov (United States)

Wozniak, Peter; Vauderwange, Oliver; Mandal, Avikarsha; Javahiraly, Nicolas; Curticapean, Dan

2016-09-01

Practical exercises are a crucial part of many curricula. Even simple exercises can improve the understanding of the underlying subject. Most experimental setups require special hardware. To carry out e. g. a lens experiments the students need access to an optical bench, various lenses, light sources, apertures and a screen. In our previous publication we demonstrated the use of augmented reality visualization techniques in order to let the students prepare with a simulated experimental setup. Within the context of our intended blended learning concept we want to utilize augmented or virtual reality techniques for stationary laboratory exercises. Unlike applications running on mobile devices, stationary setups can be extended more easily with additional interfaces and thus allow for more complex interactions and simulations in virtual reality (VR) and augmented reality (AR). The most significant difference is the possibility to allow interactions beyond touching a screen. The LEAP Motion controller is a small inexpensive device that allows for the tracking of the user's hands and fingers in three dimensions. It is conceivable to allow the user to interact with the simulation's virtual elements by the user's very hand position, movement and gesture. In this paper we evaluate possible applications of the LEAP Motion controller for simulated experiments in augmented and virtual reality. We pay particular attention to the devices strengths and weaknesses and want to point out useful and less useful application scenarios.