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Sample records for multi-component quantum gases

  1. Fast Rotating Scalar and Multi-component Bose Gases

    NASA Technical Reports Server (NTRS)

    Ho, TIn-Lun Jason

    2003-01-01

    We show that in the limit of large angular momentum, many equilibrium and dynamical phenomena of scalar and multi-component Bose gases can be accounted for by approximating the system to reside in an effective lowest Landau level. This method explains the origin of the mysterious stripe formation in fast rotating Bose gas recently observed at JILA, and accounts for all the dynamical details observed in this experiment. To further demonstrate the usefulness of this method, we present its predictions of the interference patterns of two vortex lattices, and rich vortex lattice structures in multi-component Bose gases.

  2. Topics in multi-component ultracold gases and gauge fields

    NASA Astrophysics Data System (ADS)

    Ozawa, Tomoki

    In this thesis, we present theoretical studies on three topics related to multi-component ultracold gases and gauge fields. The first topic that we discuss is artificial gauge fields in ultracold gases. Recently, methods to create artificial gauge fields coupled to neutral ultracold systems using a light-induced Berry's connection have been rapidly developing. These methods are not only capable of creating Abelian gauge fields, such as a conventional magnetic field, but also non-Abelian gauge fields, which opens a way to explore and simulate a wide variety of physical models. In this thesis, we discuss various properties of bosons with Rashba-Dresselhaus spin-orbit coupling, which is a special type of non-Abelian gauge field. We investigate the stability of Bose-Einstein condensates with Rashba-Dresselhaus spin-orbit coupling, and show that the condensates are stable against quantum and thermal fluctuations. We also consider the renormalization of the bare interaction by calculating the t-matrix and its consequence on the ground state phase diagrams. The second topic discussed here is three-component ultracold fermionic systems. It is known that ferromagnetism and superfluidity can coexist at low enough temperature in three-component ultracold fermions. In this thesis, we elucidate how fermionic pairing and population imbalance enhance each other. We also describe a crossover from Bardeen-Cooper-Schrieffer state of fermionic pairing state to the limit of Bose-Einstein condensate of three weakly interacting species of molecules, as the interaction increases. Furthermore, we find an interesting similarity in the free energies between three-component ultracold fermions and quantum chromodynamics. The last topic discussed here is Niels Bohr's double-slit interference gedankenexperiment with charged particles, which argues that the consistency of elementary quantum mechanics requires that the electromagnetic field must be quantized. In the experiment a particle's path

  3. Universal low-energy physics in 1D strongly repulsive multi-component Fermi gases

    NASA Astrophysics Data System (ADS)

    Jiang, Yuzhu; He, Peng; Guan, Xi-Wen

    2016-04-01

    It has been shown (Yang and You 2011 Chin. Phys. Lett. 28 020503) that at zero temperature the ground state of the one-dimensional (1D) w-component Fermi gas coincides with that of the spinless Bose gas in the limit ω \\to ∞ . This behavior was experimentally evidenced through quasi-1D tightly trapping ultracold 173Yb atoms in a recent paper (Pagano et al 2014 Nat. Phys. 10 198). However, understanding of low-temperature behavior of Fermi gases with a repulsive interaction requires spin-charge separated conformal field theories of an effective Tomonaga-Luttinger liquid and an antiferromagnetic SU(w) Heisenberg spin chain. Here we analytically derive universal thermodynamics of 1D strongly repulsive fermionic gases with SU(w) symmetry via the Yang-Yang thermodynamic Bethe ansatz method. The analytical free energy and magnetic properties of the systems at low temperature in a weak magnetic field are obtained through the Wiener-Hopf method. In particular, the free energy essentially manifests the spin-charge separated conformal field theories for high-symmetry systems with arbitrary repulsive interaction strength. We also find that the sound velocity of the Fermi gases in the large w limit coincides with that for the spinless Bose gas, whereas the spin velocity vanishes quickly as w becomes large. This indicates strong suppression of the Fermi exclusion statistics by the commutativity feature among the w-component fermions with different spin states in the Tomonaga-Luttinger liquid phase. Moreover, the equations of state and critical behavior of physical quantities at finite temperature are analytically derived in terms of the polylogarithm functions in the quantum critical region.

  4. Equilibration of quantum gases

    NASA Astrophysics Data System (ADS)

    Farrelly, Terry

    2016-07-01

    Finding equilibration times is a major unsolved problem in physics with few analytical results. Here we look at equilibration times for quantum gases of bosons and fermions in the regime of negligibly weak interactions, a setting which not only includes paradigmatic systems such as gases confined to boxes, but also Luttinger liquids and the free superfluid Hubbard model. To do this, we focus on two classes of measurements: (i) coarse-grained observables, such as the number of particles in a region of space, and (ii) few-mode measurements, such as phase correlators. We show that, in this setting, equilibration occurs quite generally despite the fact that the particles are not interacting. Furthermore, for coarse-grained measurements the timescale is generally at most polynomial in the number of particles N, which is much faster than previous general upper bounds, which were exponential in N. For local measurements on lattice systems, the timescale is typically linear in the number of lattice sites. In fact, for one-dimensional lattices, the scaling is generally linear in the length of the lattice, which is optimal. Additionally, we look at a few specific examples, one of which consists of N fermions initially confined on one side of a partition in a box. The partition is removed and the fermions equilibrate extremely quickly in time O(1/N).

  5. Quantum Gases in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Barmettler, Peter; Kollath, Corinna

    2015-09-01

    The experimental realization of correlated quantum phases with ultracold gases in optical lattices and their theoretical understanding has witnessed remarkable progress during the last decade. In this review we introduce basic concepts and tools to describe the many-body physics of quantum gases in optical lattices. This includes the derivation of effective lattice Hamiltonians from first principles and an overview of the emerging quantum phases. Additionally, state-of-the-art numerical tools to quantitatively treat bosons or fermions on different lattices are introduced.

  6. EDITORIAL: Cold Quantum GasesEditorial: Cold Quantum Gases

    NASA Astrophysics Data System (ADS)

    Vassen, W.; Hemmerich, A.; Arimondo, E.

    2003-04-01

    This Special Issue of Journal of Optics B: Quantum and Semiclassical Optics brings together the contributions of various researchers working on theoretical and experimental aspects of cold quantum gases. Different aspects of atom optics, matter wave interferometry, laser manipulation of atoms and molecules, and production of very cold and degenerate gases are presented. The variety of subjects demonstrates the steadily expanding role associated with this research area. The topics discussed in this issue, extending from basic physics to applications of atom optics and of cold atomic samples, include: bulletBose--Einstein condensation bulletFermi degenerate gases bulletCharacterization and manipulation of quantum gases bulletCoherent and nonlinear cold matter wave optics bulletNew schemes for laser cooling bulletCoherent cold molecular gases bulletUltra-precise atomic clocks bulletApplications of cold quantum gases to metrology and spectroscopy bulletApplications of cold quantum gases to quantum computing bulletNanoprobes and nanolithography. This special issue is published in connection with the 7th International Workshop on Atom Optics and Interferometry, held in Lunteren, The Netherlands, from 28 September to 2 October 2002. This was the last in a series of Workshops organized with the support of the European Community that have greatly contributed to progress in this area. The scientific part of the Workshop was managed by A Hemmerich, W Hogervorst, W Vassen and J T M Walraven, with input from members of the International Programme Committee who are listed below. The practical aspects of the organization were ably handled by Petra de Gijsel from the Vrije Universiteit in Amsterdam. The Workshop was funded by the European Science Foundation (programme BEC2000+), the European Networks 'Cold Quantum Gases (CQG)', coordinated by E Arimondo, and 'Cold Atoms and Ultraprecise Atomic Clocks (CAUAC)', coordinated by J Henningsen, by the German Physical Society (DFG), by

  7. Phase Diagram of Fractional Quantum Hall Effect of Composite Fermions in Multi-Component Systems

    NASA Astrophysics Data System (ADS)

    Coimbatore Balram, Ajit; Töke, Csaba; Wójs, Arkadiusz; Jain, Jainendra

    2015-03-01

    The fractional quantum Hall effect (FQHE) of composite fermions (CFs) produces delicate states arising from a weak residual interaction between CFs. We study the spin phase diagram of these states, motivated by the recent experimental observation by Liu et al. of several spin-polarization transitions at 4/5, 5/7, 6/5, 9/7, 7/9, 8/11 and 10/13 in GaAs systems. We show that the FQHE of CFs is much more prevalent in multicomponent systems, and consider the feasibility of such states for systems with N components for an SU(N) symmetric interaction. Our results apply to GaAs quantum wells, wherein electrons have two components, to AlAs quantum wells and graphene, wherein electrons have four components (two spins and two valleys), and to an H-terminated Si(111) surface, which can have six components. We provide a fairly comprehensive list of possible incompressible FQH states of CFs, their SU(N) spin content, their energies, and their phase diagram as a function of the generalized ``Zeeman'' energy. The results are in good agreement with available experiments. DOE Grant No. DE-SC0005042, Hungarian Scientific Research Funds No. K105149 (CT), the Polish NCN grant 2011/01/B/ST3/04504 and the EU Marie Curie Grant PCIG09-GA-2011-294186.

  8. Exact density profiles and symmetry classification for strongly interacting multi-component Fermi gases in tight waveguides

    NASA Astrophysics Data System (ADS)

    Decamp, Jean; Armagnat, Pacome; Fang, Bess; Albert, Mathias; Minguzzi, Anna; Vignolo, Patrizia

    2016-05-01

    We consider a mixture of one-dimensional strongly interacting Fermi gases with up to six components, subjected to a longitudinal harmonic confinement. In the limit of infinitely strong repulsions we provide an exact solution which generalizes the one for the two-component mixture. We show that an imbalanced mixture under harmonic confinement displays partial spatial separation among the components, with a structure which depends on the relative population of the various components. Furthermore, we provide a symmetry characterization of the ground and excited states of the mixture introducing and evaluating a suitable operator, namely the conjugacy class sum. We show that, even under external confinement, the gas has a definite symmetry which corresponds to the most symmetric one compatible with the imbalance among the components. This generalizes the predictions of the Lieb–Mattis theorem for a Fermionic mixture with more than two components.

  9. Magnetism in ultracold quantum gases

    NASA Astrophysics Data System (ADS)

    Schmaljohann, H.; Erhard, M.; Kronjäger, J.; Kottke, M.; van Staa, S.; Arlt, J. J.; Bongs, K.; Sengstock, K.

    2004-12-01

    We study the static and dynamic magnetic properties of ultracold quantum gases, in particular the spinor physics of F = 1 and F = 2 Bose-Einstein condensates of 87Rb atoms. Our data lead to the conclusion, that the F = 2 ground state of 87Rb is polar, while we find the F = 1 ground state to be ferromagnetic. The dynamics of spinor systems is linked to an interplay between coherent mean-field interactions, losses and interactions with atoms in the thermal cloud. Within this rich parameter space we observe indications for coherent spinor dynamics and novel thermalization regimes.

  10. Exact mapping between different dynamics of isotropically trapped quantum gases

    NASA Astrophysics Data System (ADS)

    Wamba, Etienne; Pelster, Axel; Anglin, James R.

    2016-05-01

    Experiments on trapped quantum gases can probe challenging regimes of quantum many-body dynamics, where strong interactions or non-equilibrium states prevent exact theoretical treatment. In this talk, we present a class of exact mappings between all the observables of different experiments, under the experimentally attainable conditions that the gas particles interact via a homogeneously scaling two-body potential which is in general time-dependent, and are confined in an isotropic harmonic trap. We express our result through an identity relating second-quantized field operators in the Heisenberg picture of quantum mechanics which makes it general. It applies to arbitrary measurements on possibly multi-component Bose or Fermi gases in arbitrary initial quantum states, no matter how highly excited or far from equilibrium. We use an example to show how the results of two different and currently feasible experiments can be mapped onto each other by our spacetime transformation. DAMOP sorting category: 6.11 Nonlinear dynamics and out-of-equilibrium trapped gases EW acknowledge the financial support from the Alexander von Humboldt foundation.

  11. Multi-component quantum gases in spin-dependent hexagonal lattices

    NASA Astrophysics Data System (ADS)

    Soltan-Panahi, P.; Struck, J.; Hauke, P.; Bick, A.; Plenkers, W.; Meineke, G.; Becker, C.; Windpassinger, P.; Lewenstein, M.; Sengstock, K.

    2011-05-01

    In solid-state materials, the static and dynamic properties as well as the magnetic and electronic characteristics are crucially influenced by the crystal symmetry. Hexagonal structures play a particularly important role and lead to novel physics, such as that of carbon nanotubes or graphene. Here we report on the realization of ultracold atoms in a spin-dependent optical lattice with hexagonal symmetry. We show how the combined effects of the lattice and interactions between atoms lead to a forced antiferromagnetic Néel order when two spin-components localize at different lattice sites. We also demonstrate that the coexistence of two components--one Mott-insulating and the other one superfluid--leads to an interaction-induced modulation of the superfluid density, which is observed spectroscopically. Our studies reveal the vast impact of the interaction-induced modulation on the superfluid-to-Mott-insulator transition. The observations are consistent with theoretical predictions using Gutzwiller mean-field theory.

  12. Quantum gases: The high-symmetry switch

    NASA Astrophysics Data System (ADS)

    Gorshkov, Alexey V.

    2014-10-01

    Accessing orbital exchange between highly symmetric many-component spins may hold the key to a number of exotic, strongly correlated quantum phenomena, but probing such exchange is far from easy. An experiment with ultracold gases takes on the task.

  13. Ultracold quantum gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Bloch, Immanuel

    2005-10-01

    Artificial crystals of light, consisting of hundreds of thousands of optical microtraps, are routinely created by interfering optical laser beams. These so-called optical lattices act as versatile potential landscapes to trap ultracold quantum gases of bosons and fermions. They form powerful model systems of quantum many-body systems in periodic potentials for probing nonlinear wave dynamics and strongly correlated quantum phases, building fundamental quantum gates or observing Fermi surfaces in periodic potentials. Optical lattices represent a fast-paced modern and interdisciplinary field of research.

  14. Dynamics and thermodynamics in spinor quantum gases

    NASA Astrophysics Data System (ADS)

    Schmaljohann, H.; Erhard, M.; Kronjäger, J.; Sengstock, K.; Bongs, K.

    2004-12-01

    We discuss magnetism in spinor quantum gases theoretically and experimentally with emphasis on temporal dynamics of the spinor order parameter in the presence of an external magnetic field. In a simple coupled Gross Pitaevskii picture we observe a dramatic suppression of spin dynamics due to quadratic Zeeman “dephasing”. In view of an inhomogeneous density profile of the trapped condensate we present evidence of spatial variations of spin dynamics. In addition we study spinor quantum gases as a model system for thermodynamics of Bose Einstein condensation. As a particular example we present measurements on condensate magnetisation due to the interaction with a thermal bath.

  15. Scattering in Quantum Lattice Gases

    NASA Astrophysics Data System (ADS)

    O'Hara, Andrew; Love, Peter

    2009-03-01

    Quantum Lattice Gas Automata (QLGA) are of interest for their use in simulating quantum mechanics on both classical and quantum computers. QLGAs are an extension of classical Lattice Gas Automata where the constraint of unitary evolution is added. In the late 1990s, David A. Meyer as well as Bruce Boghosian and Washington Taylor produced similar models of QLGAs. We start by presenting a unified version of these models and study them from the point of view of the physics of wave-packet scattering. We show that the Meyer and Boghosian-Taylor models are actually the same basic model with slightly different parameterizations and limits. We then implement these models computationally using the Python programming language and show that QLGAs are able to replicate the analytic results of quantum mechanics (for example reflected and transmitted amplitudes for step potentials and the Klein paradox).

  16. A New Approach to Energy Integral for Investigation of Dust—Ion Acoustic (DIA) Waves in Multi-Component Plasmas with Quantum Effects in Inertia Less Electrons

    NASA Astrophysics Data System (ADS)

    Kalita, B. C.; Kalita, R.

    2015-06-01

    Dust-ion acoustic waves are investigated in this model of plasma consisting of negatively charged dusts, cold ions and inertia less quantum effected electrons with the help of a typical energy integral. In this case, a new technique is applied formulating a differential equation to establish the energy integral in case of multi-component plasmas which is not possible in general. Dust-ion acoustic (DIA) compressive and rarefactive, supersonic and subsonic solitons of various amplitudes are established. The consideration of smaller order nonlinearity in support of the newly established quantum plasma model is observed to generate small amplitude solitons at the decrease of Mach number. The growths of soliton amplitudes and potential depths are found more sensitive to the density of quantum electrons. The small density ratio r(= 1 - f) with a little quantized electrons supplemented by the dust charges Zd and the in-deterministic new quantum parameter C2 are found responsible to finally support the generation of small amplitude solitons admissible for the model.

  17. Thermodynamics of Quantum Gases for the Entire Range of Temperature

    ERIC Educational Resources Information Center

    Biswas, Shyamal; Jana, Debnarayan

    2012-01-01

    We have analytically explored the thermodynamics of free Bose and Fermi gases for the entire range of temperature, and have extended the same for harmonically trapped cases. We have obtained approximate chemical potentials for the quantum gases in closed forms of temperature so that the thermodynamic properties of the quantum gases become…

  18. Nonlinear electrostatic coherent structures: solitary and shock waves in a dissipative, nonplanar multi-component quantum plasma

    NASA Astrophysics Data System (ADS)

    Han, Jiu-Ning; Luo, Jun-Hua; Li, Jun-Xiu

    2014-01-01

    The nonlinear propagation of ion-acoustic solitary and shock waves in a dissipative, nonplanar quantum plasma comprised of electrons, positrons, and ions are studied. A modified Korteweg-de Vries Burgers equation is derived in the limit of low frequency and long wavelength by taking into account the kinematic viscosity among the plasma constituents. It is shown that this plasma system supports the propagation of both compressive and rarefactive nonlinear waves. The effects of variation of various plasma parameters on the time evolution of nonplanar solitary waves, the profile of shock waves, and the nonlinear structure induced by the collision of solitary waves are discussed. It is found that these parameters have significant effects on the properties of nonlinear waves in cylindrical and spherical geometries, and these effects for compressive and rarefactive nonlinear waves are obviously different.

  19. In Situ Imaging of Atomic Quantum Gases

    NASA Astrophysics Data System (ADS)

    Hung, Chen-Lung; Chin, Cheng

    2015-09-01

    One exciting progress in recent cold atom experiments is the development of high resolution, in situ imaging techniques for atomic quantum gases.1-3 These new powerful tools provide detailed information on the distribution of atoms in a trap with resolution approaching the level of single atom and even single lattice site, and complement the welldeveloped time-of-flight method that probes the system in momentum space. In a condensed matter analogy, this technique is equivalent to locating electrons of a material in a snap shot. In situ imaging has offered a new powerful tool to study atomic gases and inspired many new research directions and ideas. In this chapter, we will describe the experimental setup of in situ absorption imaging, observables that can be extracted from the images, and new physics that can be explored with this technique.

  20. Deviation from the Knudsen law on quantum gases

    SciTech Connect

    Babac, Gulru

    2014-12-09

    Gas flow in micro/nano scale systems has been generally studied for the Maxwell gases. In the limits of very low temperature and very confined domains, the Maxwellian approximation can break down and the quantum character of the gases becomes important. In these cases, Knudsen law, which is one of the important equations to analyze rarefied gas flows is invalid and should be reanalyzed for quantum gases. In this work, the availability of quantum gas conditions in the high Knudsen number cases is discussed and Knudsen law is analyzed for quantum gases.

  1. Quantum gases and white dwarfs with quantum gravity

    NASA Astrophysics Data System (ADS)

    Moussa, Mohamed

    2014-11-01

    This paper addresses the effect of a generalized uncertainty principle produced by different approaches of quantum gravity within the Planck scale on statistical and thermodynamical properties of ideal fermion and boson gases. The partition function and some thermodynamical properties are investigated. The Bose-Einstein condensation and the ground state properties of fermion gases are also considered. The target approach is extended to a white dwarf as an application. The modified mass-radius relation is calculated. A decrease in the pressure of degenerate fermions due to the presence of quantum gravity leads to a contraction in the star radius. It is also found that the gravity background does not result in any change in white dwarf stability.

  2. [Using 2-DCOS to identify the molecular spectrum peaks for the isomer in the multi-component mixture gases Fourier transform infrared analysis].

    PubMed

    Zhao, An-Xin; Tang, Xiao-Jun; Zhang, Zhong-Hua; Liu, Jun-Hua

    2014-10-01

    The generalized two-dimensional correlation spectroscopy and Fourier transform infrared were used to identify hydrocarbon isomers in the mixed gases for absorption spectra resolution enhancement. The Fourier transform infrared spectrum of n-butane and iso-butane and the two-dimensional correlation infrared spectrum of concentration perturbation were used for analysis as an example. The all band and the main absorption peak wavelengths of Fourier transform infrared spectrum for single component gas showed that the spectra are similar, and if they were mixed together, absorption peaks overlap and peak is difficult to identify. The synchronous and asynchronous spectrum of two-dimensional correlation spectrum can clearly identify the iso-butane and normal butane and their respective characteristic absorption peak intensity. Iso-butane has strong absorption characteristics spectrum lines at 2,893, 2,954 and 2,893 cm(-1), and n-butane at 2,895 and 2,965 cm(-1). The analysis result in this paper preliminary verified that the two-dimensional infrared correlation spectroscopy can be used for resolution enhancement in Fourier transform infrared spectrum quantitative analysis. PMID:25739197

  3. Peltier cooling of fermionic quantum gases.

    PubMed

    Grenier, Ch; Georges, A; Kollath, C

    2014-11-14

    We propose a cooling scheme for fermionic quantum gases, based on the principles of the Peltier thermoelectric effect and energy filtering. The system to be cooled is connected to another harmonically trapped gas acting as a reservoir. The cooling is achieved by two simultaneous processes: (i) the system is evaporatively cooled, and (ii) cold fermions from deep below the Fermi surface of the reservoir are injected below the Fermi level of the system, in order to fill the "holes" in the energy distribution. This is achieved by a suitable energy dependence of the transmission coefficient connecting the system to the reservoir. The two processes can be viewed as simultaneous evaporative cooling of particles and holes. We show that both a significantly lower entropy per particle and faster cooling rate can be achieved in this way than by using only evaporative cooling. PMID:25432033

  4. Quantum gases in trimerized kagome lattices

    SciTech Connect

    Damski, B.; Fehrmann, H.; Everts, H.-U.; Baranov, M.; Santos, L.; Lewenstein, M.

    2005-11-15

    We study low-temperature properties of atomic gases in trimerized optical kagome lattices. The laser arrangements that can be used to create these lattices are briefly described. We also present explicit results for the coupling constants of the generalized Hubbard models that can be realized in such lattices. In the case of a single-component Bose gas the existence of a Mott insulator phase with fractional numbers of particles per trimer is verified in a mean-field approach. The main emphasis of the paper is on an atomic spinless interacting Fermi gas in the trimerized kagome lattice with two fermions per site. This system is shown to be described by a quantum spin-1/2 model on the triangular lattice with couplings that depend on the bond directions. We investigate this model by means of exact diagonalization. Our key finding is that the system exhibits nonstandard properties of a quantum spin-liquid crystal: it combines planar antiferromagnetic order in the ground state with an exceptionally large number of low-energy excitations. The possibilities of experimental verification of our theoretical results are critically discussed.

  5. Ultracold Quantum Gases in Hexagonal Optical Lattices

    NASA Astrophysics Data System (ADS)

    Sengstock, Klaus

    2010-03-01

    Hexagonal structures occur in a vast variety of systems, ranging from honeycombs of bees in life sciences to carbon nanotubes in material sciences. The latter, in particular its unfolded two-dimensional layer -- Graphene -- has rapidly grown to one of the most discussed topics in condensed-matter physics. Not only does it show proximity to various carbon-based materials but also exceptional properties owing to its unusual energy spectrum. In quantum optics, ultracold quantum gases confined in periodic light fields have shown to be very general and versatile instruments to mimic solid state systems. However, so far nearly all experiments were performed in cubic lattice geometries only. Here we report on the first experimental realization of ultracold quantum gases in a state-dependent, two-dimensional, Graphene-like optical lattice with hexagonal symmetry. The lattice is realized via a spin-dependent optical lattice structure with alternating σ^+ and σ^- -sites and thus constitutes a so called `magnetic'-lattice with `antiferromagnetic'-structure. Atoms with different spin orientation can be loaded to specific lattice sites or -- depending on the parameters -- to the whole lattice. As a consequence e.g. superpositions of a superfluid spin component with a different spin component in the Mott-insulating phase can be realized as well as spin-dependent transport properties, disorder etc. After preparing an antiferromagnetically ordered state we e.g. measure sustainable changes of the transport properties of the atoms. This manifests in a significant reduction of the tunneling as compared to a single-component system. We attribute this observation to a partial tunneling blockade for one spin component induced by population in another spin component localized at alternating lattice sites. Within a Gutzwiller-Ansatz we calculate the phase diagrams for the mixed spin-states and find very good agreement with our experimental results. Moreover, by state-resolved recording

  6. Statistically interacting quantum gases in D dimensions

    NASA Astrophysics Data System (ADS)

    Potter, Geoffrey G.

    Chapter 1. Exact and explicit results are derived for the thermodynamic properties (isochores, isotherms, isobars, response functions, speed of sound) of a quantum gas in dimensions D ≥ 1 and with fractional exclusion statistics 0 ≤ g ≤ 1 connecting bosons (g = 0) and fermions (g = 1). In D = 1 the results are equivalent to those of the Calogero-Sutherland model, a gas with long-range two-body interaction. Emphasis is given to the crossover between boson-like and fermion-like features, caused by aspects of the statistical interaction that mimic long-range attraction and short-range repulsion. A phase transition along the isobar occurs at a nonzero temperature in all dimensions. The T-dependence of the speed of sound is in simple relation to isochores and isobars. The effects of soft container walls are accounted for rigorously for the case of a pure power-law potential. Chapter 2. The exact thermodynamics (isochores, isotherms, isobars, response functions, speed of sound) is worked out for a statistically interacting quantum gas in D dimensions. The results in D = 1 are those of the thermodynamic Bethe ansatz for the Nonlinear Schrodinger model, a gas with repulsive two-body contact potential. In all dimensions the ideal boson and fermion gases are recovered in the weak-coupling and strong-coupling limits, respectively. For all nonzero couplings ideal fermion gas behavior emerges for D >> 1 and, in the limit D → infinity, a phase transition occurs at T > 0. Significant deviations from ideal quantum gas behavior are found for intermediate coupling and finite D . Chapter 3. Methodology previously developed in the framework of the coordinate Bethe ansatz applied to integrable quantum gas models is employed to calculate some ground-state properties and elementary excitations for quantum gas models in D = 1 dimensions with statistical interactions that are not equivalent to dynamical interactions. The focus in this comparative study is on modifications of the

  7. Single particle density of trapped interacting quantum gases

    SciTech Connect

    Bala, Renu; Bosse, J.; Pathak, K. N.

    2015-05-15

    An expression for single particle density for trapped interacting gases has been obtained in first order of interaction using Green’s function method. Results are easily simplified for homogeneous quantum gases and are found to agree with famous results obtained by Huang-Yang-Luttinger and Lee-Yang.

  8. Probing 1D super-strongly correlated dipolar quantum gases

    NASA Astrophysics Data System (ADS)

    Citro, R.; de Palo, S.; Orignac, E.; Pedri, P.; Chiofalo, M.-L.

    2009-04-01

    One-dimensional (1D) dipolar quantum gases are characterized by a very special condition where super-strong correlations occur to significantly affect the static and dynamical low-energy behavior. This behavior is accurately described by the Luttinger Liquid theory with parameter K < 1. Dipolar Bose gases are routinely studied in laboratory with Chromium atoms. On the other hand, 1D realizations with molecular quantum gases can be at reach of current experimental expertises, allowing to explore such extreme quantum degenerate conditions which are the bottom line for designing technological devices. Aim of the present contribution is to focus on the possible probes expected to signal the reach of Luttinger-Liquid behavior in 1D dipolar gases.

  9. Spin-orbit-coupled quantum gases

    NASA Astrophysics Data System (ADS)

    Radic, Juraj

    The dissertation explores the effects of synthetic spin-orbit coupling on the behaviour of quantum gases in several different contexts. We first study realistic methods to create vortices in spin-orbit-coupled (SOC) Bose-Einstein condensates (BEC). We propose two different methods to induce thermodynamically stable static vortex configurations: (1) to rotate both the Raman lasers and the anisotropic trap; and (2) to impose a synthetic Abelian field on top of synthetic spin-orbit interactions. We solve the Gross-Pitaevskii equation for several experimentally relevant regimes and find new interesting effects such as spatial separation of left- and right-moving spin-orbit-coupled condensates, and the appearance of unusual vortex arrangements. Next we consider cold atoms in an optical lattice with synthetic SOC in the Mott-insulator regime. We calculate the parameters of the corresponding tight-binding model and derive the low-energy spin Hamiltonian which is a combination of Heisenberg model, quantum compass model and Dzyaloshinskii-Moriya interaction. We find that the Hamiltonian supports a rich classical phase diagram with collinear, spiral and vortex phases. Next we study the time evolution of the magnetization in a Rashba spin-orbit-coupled Fermi gas, starting from a fully-polarized initial state. We model the dynamics using a Boltzmann equation, which we solve in the Hartree-Fock approximation. The resulting non-linear system of equations gives rise to three distinct dynamical regimes controlled by the ratio of interaction and spin-orbit-coupling strength lambda: for small lambda, the magnetization decays to zero. For intermediate lambda, it displays undamped oscillations about zero and for large lambda, a partially magnetized state is dynamically stabilized. Motivated by an interesting stripe phase which appears in BEC with SOC [Li et al., Phys. Rev. Lett. 108, 225301 (2011)], we study the finite-temperature phase diagram of a pseudospin-1/2 Bose gas with

  10. New directions for quantum lattice gases

    NASA Astrophysics Data System (ADS)

    Love, Peter

    2010-03-01

    Quantum Lattice Gas Automata are an extension of classical Lattice Gas Automata with the added constraints of linearity and unitary evolution. They were defined in the late 1990s by Meyer, and Boghosian and Taylor. We present a unified version of these models and study them from the point of view of the quantum simulation of problems of quantum dynamics of practical interest including chemical reactive scattering.

  11. Quantum simulation of magnetic kinks with dipolar lattice gases

    NASA Astrophysics Data System (ADS)

    Cao, Lushuai; Yin, Xiangguo; Schmelcher, Peter

    2015-05-01

    We propose an effective Ising spin chain constructed with dipolar quantum gases confined in a one-dimensional optical superlattice. Mapping the motional degrees of freedom of a single particle in the lattice onto a pseudo-spin results in effective transverse and longitudinal magnetic fields. This effective Ising spin chain exhibits a quantum phase transition from a paramagnetic to a single-kink phase as the dipolar interaction increases. Particularly in the single-kink phase, a magnetic kink arises in the effective spin chain and behaves as a quasi-particle in a pinning potential exerted by the longitudinal magnetic field. Being realizable with current experimental techniques, this effective Ising chain presents a unique platform for emulating the quantum phase transition as well as the magnetic kink effects in the Ising-spin chain and enriches the toolbox for quantum emulation of spin models by ultracold quantum gases.

  12. Orbital excitation blockade and algorithmic cooling in quantum gases.

    PubMed

    Bakr, Waseem S; Preiss, Philipp M; Tai, M Eric; Ma, Ruichao; Simon, Jonathan; Greiner, Markus

    2011-12-22

    Interaction blockade occurs when strong interactions in a confined, few-body system prevent a particle from occupying an otherwise accessible quantum state. Blockade phenomena reveal the underlying granular nature of quantum systems and allow for the detection and manipulation of the constituent particles, be they electrons, spins, atoms or photons. Applications include single-electron transistors based on electronic Coulomb blockade and quantum logic gates in Rydberg atoms. Here we report a form of interaction blockade that occurs when transferring ultracold atoms between orbitals in an optical lattice. We call this orbital excitation blockade (OEB). In this system, atoms at the same lattice site undergo coherent collisions described by a contact interaction whose strength depends strongly on the orbital wavefunctions of the atoms. We induce coherent orbital excitations by modulating the lattice depth, and observe staircase-like excitation behaviour as we cross the interaction-split resonances by tuning the modulation frequency. As an application of OEB, we demonstrate algorithmic cooling of quantum gases: a sequence of reversible OEB-based quantum operations isolates the entropy in one part of the system and then an irreversible step removes the entropy from the gas. This technique may make it possible to cool quantum gases to have the ultralow entropies required for quantum simulation of strongly correlated electron systems. In addition, the close analogy between OEB and dipole blockade in Rydberg atoms provides a plan for the implementation of two-quantum-bit gates in a quantum computing architecture with natural scalability. PMID:22193104

  13. Multi-Component Dark Matter

    SciTech Connect

    Zurek, Kathryn M.

    2008-11-01

    We explore multi-component dark matter models where the dark sector consists of multiple stable states with different mass scales, and dark forces coupling these states further enrich the dynamics. The multi-component nature of the dark matter naturally arises in supersymmetric models, where both R parity and an additional symmetry, such as a Z{sub 2}, is preserved. We focus on a particular model where the heavier component of dark matter carries lepton number and annihilates mostly to leptons. The heavier component, which is essentially a sterile neutrino, naturally explains the PAMELA, ATIC and synchrotron signals, without an excess in antiprotons which typically mars other models of weak scale dark matter. The lighter component, which may have a mass from a GeV to a TeV, may explain the DAMA signal, and may be visible in low threshold runs of CDMS and XENON, which search for light dark matter.

  14. Ultracold quantum gases in triangular optical lattices

    NASA Astrophysics Data System (ADS)

    Becker, C.; Soltan-Panahi, P.; Kronjäger, J.; Dörscher, S.; Bongs, K.; Sengstock, K.

    2010-06-01

    Over recent years, exciting developments in the field of ultracold atoms confined in optical lattices have led to numerous theoretical proposals devoted to the quantum simulation of problems e.g. known from condensed matter physics. Many of those ideas demand experimental environments with non-cubic lattice geometries. In this paper, we report on the implementation of a versatile three-beam lattice allowing for the generation of triangular as well as hexagonal optical lattices. As an important step, the superfluid-Mott insulator (SF-MI) quantum phase transition has been observed and investigated in detail in this lattice geometry for the first time. In addition to this, we study the physics of spinor Bose-Einstein condensates (BEC) in the presence of the triangular optical lattice potential, especially spin changing dynamics across the SF-MI transition. Our results suggest that, below the SF-MI phase transition, a well-established mean-field model describes the observed data when renormalizing the spin-dependent interaction. Interestingly, this opens up new perspectives for a lattice-driven tuning of a spin dynamics resonance occurring through the interplay of the quadratic Zeeman effect and spin-dependent interaction. Finally, we discuss further lattice configurations that can be realized with our setup.

  15. A new apparatus for studying quantum gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Schneider, Ulrich; Duca, Lucia; Li, Tracy; Boll, Martin; Ronzheimer, Philipp; Braun, Simon; Will, Sebastian; Rom, Tim; Schreiber, Michael; Bloch, Immanuel

    2011-05-01

    We present the design of a new apparatus targeted at the study of equilibrium and out-of-equilibrium phenomena of quantum gases in 2D and 3D optical lattices. Specifically this apparatus will allow for a study of the crossover between 2D and 3D using bosonic and fermionic gases as well as Bose-Fermi mixtures. In addition we present a new analysis of previous results concerning the Fermi-Hubbard model and will analyze possible routes for creating many-body states with long range order, including antiferromagnetically ordered states and BCS-superfluids. This work is supported by DARPA/OLE MURI DFG MPQ.

  16. Atomic Quantum Gases in Kagomé Lattices

    NASA Astrophysics Data System (ADS)

    Santos, L.; Baranov, M. A.; Cirac, J. I.; Everts, H.-U.; Fehrmann, H.; Lewenstein, M.

    2004-07-01

    We demonstrate the possibility of creating and controlling an ideal and trimerized optical Kagomé lattice, and study the low temperature physics of various atomic gases in such lattices. In the trimerized Kagomé lattice, a Bose gas exhibits a Mott transition with fractional filling factors, whereas a spinless interacting Fermi gas at 2/3 filling behaves as a quantum magnet on a triangular lattice. Finally, a Fermi-Fermi mixture at half-filling for both components represents a frustrated quantum antiferromagnet with a resonating-valence-bond ground state and quantum spin liquid behavior dominated by a continuous spectrum of singlet and triplet excitations. We discuss the method of preparing and observing such a quantum spin liquid employing molecular Bose condensates.

  17. Excitations of quantum gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Yesilada, Emek

    This thesis describes experiments that studied the excitations of an ultra-cold atomic Rb gas in an optical lattice using Bragg spectroscopy. A Bose-Einstein condensate (BEC) of 87Rb was formed in a cloverleaf trap. An optical lattice of cubic symmetry, formed by the interference of six laser beams, was superimposed on the Rb BEC and turned on adiabatically. Such a system is well described by the Bose-Hubbard model, which predicts a quantum phase transition from a superfluid to a Mott insulator state at a critical lattice depth. In the first experiment, we studied the superfluid regime. The superfluid admits sound waves as phonon excitations. In two photon Bragg spectroscopy two laser beams intersecting at angle on the condensate create such excitations. The excitation spectrum of BEC was measured in a three dimensional optical lattice as a function of lattice strength. In the second experiment we studied the excitation spectrum of the Mott insulator. The lowest energy excitations in such a system are particle-hole excitations. These correspond to the hopping of atoms from one lattice site to another. The insulating phase is characterized by a gap in the excitation spectrum and we measured this particle-hole gap by Bragg spectroscopy. The precise nature of our measurement allowed us to study the opening of the excitation gap that has previously eluded experimental verification.

  18. Quantum fluctuations of vortex lattices in ultracold gases

    NASA Astrophysics Data System (ADS)

    Kwasigroch, M. P.; Cooper, N. R.

    2012-12-01

    We discuss the effects of quantum fluctuations on the properties of vortex lattices in rapidly rotating ultracold atomic gases. We develop a variational method that goes beyond the Bogoliubov theory by including the effects of interactions between the quasiparticle excitations. These interactions are found to have significant quantitative effects on physical properties even at relatively large filling factors. We use our theory to predict the expected experimental signatures of quantum fluctuations of vortices and to assess the competition of the triangular vortex lattice phase with other phases in finite-sized systems.

  19. Multiphoton interband excitations of quantum gases in driven optical lattices

    NASA Astrophysics Data System (ADS)

    Weinberg, M.; Ölschläger, C.; Sträter, C.; Prelle, S.; Eckardt, A.; Sengstock, K.; Simonet, J.

    2015-10-01

    We report on the observation of multiphoton interband absorption processes for quantum gases in shaken light crystals. Periodic inertial forcing, induced by a spatial motion of the lattice potential, drives multiphoton interband excitations of up to the ninth order. The occurrence of such excitation features is systematically investigated with respect to the potential depth and the driving amplitude. Ab initio calculations of resonance positions as well as numerical evaluation of their strengths exhibit good agreement with experimental data. In addition our findings could make it possible to reach novel phases of quantum matter by tailoring appropriate driving schemes.

  20. All-optical production of 6Li quantum gases

    NASA Astrophysics Data System (ADS)

    Burchianti, A.; Seman, J. A.; Valtolina, G.; Morales, A.; Inguscio, M.; Zaccanti, M.; Roati, G.

    2015-03-01

    We report efficient production of quantum gases of 6Li using a sub-Doppler cooling scheme based on the D1 transition. After loading in a standard magneto-optical trap, an atomic sample of 109 atoms is cooled at a temperature of 40 μK by a bichromatic D1 gray-molasses. More than 2×107 atoms are then transferred into a high-intensity optical dipole trap, where a two-spin state mixture is evaporatively cooled down to quantum degeneracy. We observe that D1 cooling remains effective in the deep trapping potential, allowing an effective increase of the atomic phase-space density before starting the evaporation. In a total experimental cycle of 11 s, we produce weakly-interacting degenerate Fermi gases of 7×105 atoms at T/TF < 0.1 and molecular Bose-Einstein condensates of up 5×105 molecules. We further describe a simple and compact optical system both for high-resolution imaging and for imprinting a thin optical barrier on the atomic cloud; this represents a first step towards the study of quantum tunneling in strongly interacting superfluid Fermi gases.

  1. From quantum cellular automata to quantum lattice gases

    SciTech Connect

    Meyer, D.A.

    1996-12-01

    A natural architecture for nanoscale quantum computation is that of a quantum cellular automaton. Motivated by this observation, we begin an investigation of exactly unitary cellular automata. After proving that there can be no nontrivial, homogeneous, local, unitary, scalar cellular automaton in one dimension, we weaken the homogeneity condition and show that there are nontrivial, exactly unitary, partitioning cellular automata. We find a one-parameter family of evolution rules which are best interpreted as those for a one-particle quantum automaton. This model is naturally reformulated as a two component cellular automaton which we demonstrate to limit to the Dirac equation. We describe two generalizations of this automaton, the second of which, to multiple interacting particles, is the correct definition of a quantum lattice gas.

  2. Towards Quantum Magnetism with Ultracold Quantum Gases in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Bloch, Immanuel

    2008-05-01

    Quantum mechanical superexchange interactions form the basis of quantum magnetism in strongly correlated electronic media and are believed to play a major role in high-Tc superconducting materials. We report on the first direct measurement of such superexchange interactions with ultracold atoms in optical lattices. After preparing a spin-mixture of ultracold atoms with the help of optical superlattices in an antiferromagnetically ordered state, we are able to observe a coherent superexchange mediated spin dynamics down to coupling energies as low as 5 Hz. Furthermore, it is shown how these superexchange interactions can be fully controlled in magnitude and sign. The prospects of using such superexchange interactions for the investigation of dynamical behaviour in quantum spin systems and for quantum information processing will be outlined in the talk. In addition we present results on the dynamical resolved co-tunneling of repulsively bound atom pairs in optical superlattices and show how by using ``Coulomb-blockade'' type tunneling resonance one can count atoms one by one to determine their number statistics in the lattice potential. Finally, latest results on ultracold Fermions and Bose-Fermi mixtures in optical lattices will be presented.

  3. Towards Quantum Magnetism with Ultracold Quantum Gases in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Bloch, Immanuel

    2008-03-01

    Quantum mechanical superexchange interactions form the basis of quantum magnetism in strongly correlated electronic media and are believed to play a major role in high-Tc superconducting materials. We report on the first direct measurement of such superexchange interactions with ultracold atoms in optical lattices. After preparing a spin-mixture of ultracold atoms with the help of optical superlattices in an antiferromagnetically ordered state, we are able to observe a coherent superexchange mediated spin dynamics down to coupling energies as low as 5 Hz. Furthermore, it is shown how these superexchange interactions can be fully controlled in magnitude and sign. The prospects of using such superexchange interactions for the investigation of dynamical behaviour in quantum spin systems and for quantum information processing will be outlined in the talk. In addition we present results on the dynamical resolved co-tunnelling of repulsively bound atom pairs in optical superlattices and show how by using ``Coulomb-blockade'' type tunnelling resonance one can count atoms one by one to determine their number statistics in the lattice potential. Finally, latest results on ultracold Fermions and Bose-Fermi mixtures in optical lattices will be presented.

  4. Multi-component assembly casting

    SciTech Connect

    James, Allister W.

    2015-10-13

    Multi-component vane segment and method for forming the same. Assembly includes: positioning a pre-formed airfoil component (12) and a preformed shroud heat resistant material (18) in a mold, wherein the airfoil component (12) and the shroud heat resistant material (18) each comprises an interlocking feature (24); preheating the mold; introducing molten structural material (46) into the mold; and solidifying the molten structural material such that it interlocks the pre-formed airfoil component (12) with respect to the preformed shroud heat resistant material (18) and is effective to provide structural support for the shroud heat resistant material (18). Surfaces between the airfoil component (12) and the structural material (46), between the airfoil component (12) and the shroud heat resistant material (18), and between the shroud heat resistant material (18) and the structural material (46) are free of metallurgical bonds.

  5. Quantum gases. Observation of isolated monopoles in a quantum field.

    PubMed

    Ray, M W; Ruokokoski, E; Tiurev, K; Möttönen, M; Hall, D S

    2015-05-01

    Topological defects play important roles throughout nature, appearing in contexts as diverse as cosmology, particle physics, superfluidity, liquid crystals, and metallurgy. Point defects can arise naturally as magnetic monopoles resulting from symmetry breaking in grand unified theories. We devised an experiment to create and detect quantum mechanical analogs of such monopoles in a spin-1 Bose-Einstein condensate. The defects, which were stable on the time scale of our experiments, were identified from spin-resolved images of the condensate density profile that exhibit a characteristic dependence on the choice of quantization axis. Our observations lay the foundation for experimental studies of the dynamics and stability of topological point defects in quantum systems. PMID:25931553

  6. Nonequilibrium steady states of ideal bosonic and fermionic quantum gases

    NASA Astrophysics Data System (ADS)

    Vorberg, Daniel; Wustmann, Waltraut; Schomerus, Henning; Ketzmerick, Roland; Eckardt, André

    2015-12-01

    We investigate nonequilibrium steady states of driven-dissipative ideal quantum gases of both bosons and fermions. We focus on systems of sharp particle number that are driven out of equilibrium either by the coupling to several heat baths of different temperature or by time-periodic driving in combination with the coupling to a heat bath. Within the framework of (Floquet-)Born-Markov theory, several analytical and numerical methods are described in detail. This includes a mean-field theory in terms of occupation numbers, an augmented mean-field theory taking into account also nontrivial two-particle correlations, and quantum-jump-type Monte Carlo simulations. For the case of the ideal Fermi gas, these methods are applied to simple lattice models and the possibility of achieving exotic states via bath engineering is pointed out. The largest part of this work is devoted to bosonic quantum gases and the phenomenon of Bose selection, a nonequilibrium generalization of Bose condensation, where multiple single-particle states are selected to acquire a large occupation [Phys. Rev. Lett. 111, 240405 (2013), 10.1103/PhysRevLett.111.240405]. In this context, among others, we provide a theory for transitions where the set of selected states changes, describe an efficient algorithm for finding the set of selected states, investigate beyond-mean-field effects, and identify the dominant mechanisms for heat transport in the Bose-selected state.

  7. Nonequilibrium steady states of ideal bosonic and fermionic quantum gases.

    PubMed

    Vorberg, Daniel; Wustmann, Waltraut; Schomerus, Henning; Ketzmerick, Roland; Eckardt, André

    2015-12-01

    We investigate nonequilibrium steady states of driven-dissipative ideal quantum gases of both bosons and fermions. We focus on systems of sharp particle number that are driven out of equilibrium either by the coupling to several heat baths of different temperature or by time-periodic driving in combination with the coupling to a heat bath. Within the framework of (Floquet-)Born-Markov theory, several analytical and numerical methods are described in detail. This includes a mean-field theory in terms of occupation numbers, an augmented mean-field theory taking into account also nontrivial two-particle correlations, and quantum-jump-type Monte Carlo simulations. For the case of the ideal Fermi gas, these methods are applied to simple lattice models and the possibility of achieving exotic states via bath engineering is pointed out. The largest part of this work is devoted to bosonic quantum gases and the phenomenon of Bose selection, a nonequilibrium generalization of Bose condensation, where multiple single-particle states are selected to acquire a large occupation [Phys. Rev. Lett. 111, 240405 (2013)]. In this context, among others, we provide a theory for transitions where the set of selected states changes, describe an efficient algorithm for finding the set of selected states, investigate beyond-mean-field effects, and identify the dominant mechanisms for heat transport in the Bose-selected state. PMID:26764644

  8. Quantum interference of high-order harmonics from mixed gases

    NASA Astrophysics Data System (ADS)

    González-Fernández, A.; Velarde, P.

    2016-08-01

    We present a theoretical study about the interference of the harmonics generated by a mixture of two gases, He-Ne. Our model is based on the electron quantum paths, a discrete number of electron trajectories, and continuum-bound transitions. A laser with intensity around 1014W/cm2 that interacts with a mixture of gases, He-Ne, produces an interference that is destructive at the low-order harmonics and oscillates between constructive and destructive near to cutoff. This destructive interference at high-order harmonics may be used to explore other transitions, which are currently hidden. At low-order harmonic frequencies, our numerical results are in very good agreement with experimental data. At higher-order harmonics, where there are no experimental data, comparison is with a Schrödinger solver.

  9. Stopping power of two-dimensional spin quantum electron gases

    NASA Astrophysics Data System (ADS)

    Zhang, Ya; Jiang, Wei; Yi, Lin

    2015-04-01

    Quantum effects can contribute significantly to the electronic stopping powers in the interactions between the fast moving beams and the degenerate electron gases. From the Pauli equation, the spin quantum hydrodynamic (SQHD) model is derived and used to calculate the stopping power and the induced electron density for protons moving above a two-dimensional (2D) electron gas with considering spin effect under an external in-plane magnetic field. In our calculation, the stopping power is not only modulated by the spin direction, but also varied with the strength of the spin effect. It is demonstrated that the spin effect can obviously enhance or reduce the stopping power of a 2D electron gas within a laboratory magnetic field condition (several tens of Tesla), thus a negative stopping power appears at some specific proton velocity, which implies the protons drain energy from the Pauli gas, showing another significant example of the low-dimensional physics.

  10. Glimmers of a Quantum KAM Theorem: Insights from Quantum Quenches in One-Dimensional Bose Gases

    NASA Astrophysics Data System (ADS)

    Brandino, G. P.; Caux, J.-S.; Konik, R. M.

    2015-10-01

    Real-time dynamics in a quantum many-body system are inherently complicated and hence difficult to predict. There are, however, a special set of systems where these dynamics are theoretically tractable: integrable models. Such models possess nontrivial conserved quantities beyond energy and momentum. These quantities are believed to control dynamics and thermalization in low-dimensional atomic gases as well as in quantum spin chains. But what happens when the special symmetries leading to the existence of the extra conserved quantities are broken? Is there any memory of the quantities if the breaking is weak? Here, in the presence of weak integrability breaking, we show that it is possible to construct residual quasiconserved quantities, thus providing a quantum analog to the KAM theorem and its attendant Nekhoreshev estimates. We demonstrate this construction explicitly in the context of quantum quenches in one-dimensional Bose gases and argue that these quasiconserved quantities can be probed experimentally.

  11. Dynamics of uniform quantum gases, I: Density and current correlations

    NASA Astrophysics Data System (ADS)

    Bosse, J.; Pathak, K. N.; Singh, G. S.

    2010-02-01

    A unified approach valid for any wavenumber q, frequency ω, and temperature T is presented for uniform ideal quantum gases allowing for a comprehensive study of number density and particle-current density response functions. Exact analytical expressions are obtained for spectral functions in terms of polylogarithms. Also, particle-number and particle-current static susceptibilities are presented which, for fugacity less than unity, additionally involve Kummer functions. The q- and T-dependent transverse-current static susceptibility is used to show explicitly that current correlations are of long range in a Bose-condensed uniform ideal gas but for bosons at T>Tc and for Fermi and Boltzmann gases at all temperatures these correlations are of short range. Contact repulsive interactions for systems of neutral quantum particles are considered within the random phase approximation. The expressions for particle-number and transverse-current susceptibilities are utilized to discuss the existence or nonexistence of superfluidity in the systems under consideration.

  12. Focus on strongly correlated quantum fluids: from ultracold quantum gases to QCD plasmas Focus on strongly correlated quantum fluids: from ultracold quantum gases to QCD plasmas

    NASA Astrophysics Data System (ADS)

    Adams, Allan; Carr, Lincoln D.; Schaefer, Thomas; Steinberg, Peter; Thomas, John E.

    2013-04-01

    The last few years have witnessed a dramatic convergence of three distinct lines of research concerned with different kinds of extreme quantum matter. Two of these involve new quantum fluids that can be studied in the laboratory, ultracold quantum gases and quantum chromodynamics (QCD) plasmas. Even though these systems involve vastly different energy scales, the physical properties of the two quantum fluids are remarkably similar. The third line of research is based on the discovery of a new theoretical tool for investigating the properties of extreme quantum matter, holographic dualties. The main goal of this focus issue is to foster communication and understanding between these three fields. We proceed to describe each in more detail. Ultracold quantum gases offer a new paradigm for the study of nonperturbative quantum many-body physics. With widely tunable interaction strength, spin composition, and temperature, using different hyperfine states one can model spin-1/2 fermions, spin-3/2 fermions, and many other spin structures of bosons, fermions, and mixtures thereof. Such systems have produced a revolution in the study of strongly interacting Fermi systems, for example in the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) crossover region, where a close collaboration between experimentalists and theorists—typical in this field—enabled ground-breaking studies in an area spanning several decades. Half-way through this crossover, when the scattering length characterizing low-energy collisions diverges, one obtains a unitary quantum gas, which is universal and scale invariant. The unitary gas has close parallels in the hydrodynamics of QCD plasmas, where the ratio of viscosity to entropy density is extremely low and comparable to the minimum viscosity conjecture, an important prediction of AdS/CFT (see below). Exciting developments in the thermodynamic and transport properties of strongly interacting Fermi gases are of broad

  13. From cavity QED with quantum gases to optomechanics

    SciTech Connect

    Ritsch, Helmut

    2011-10-03

    We study the nonlinear coupled dynamics of ultra-cold quantum gases trapped in the light field of high Q optical resonators. In the very low temperature limit the quantum nature of both, light and ultra-cold matter play equally important roles. Using the dynamically generated entanglement and properly designed measurements procedures of the light field allows controlled preparation of many-body atomic states as e.g. atom number squeezed states or Schroedinger cat states. If one traps the particles inside the optical cavity, one can create a optical potential, which is a quantized and a dynamical variable itself. In addition it mediates controllable long range interactions. The self-consistent solution for light and particles the includes new classes of quantum many-body states as super-solid states and polaron like excitations. In the deep trap limit the collective coupling of the particles and the field can be tailored to reproduce a wide range of optomechanic Hamiltonians with linear, quadratic or even higher order couplings in an environment very close to zero temperature.

  14. Dynamics of uniform quantum gases, II: Magnetic susceptibility

    NASA Astrophysics Data System (ADS)

    Bosse, J.; Pathak, K. N.; Singh, G. S.

    2010-03-01

    A general expression for temperature-dependent magnetic susceptibility of quantum gases composed of particles possessing both charge and spin degrees of freedom has been obtained within the framework of the generalized random phase approximation. The conditions for the existence of dia-, para-, and ferro-magnetism have been analyzed in terms of a parameter involving single-particle charge and spin. The limit T→0 retrieves the expressions for the Landau and the Pauli susceptibilities for an electron gas. It is found for a Bose gas that on decreasing the temperature, it passes either through a diamagnetic incomplete Meissner-effect regime or through a paramagnetic-ferromagnetic large magnetization fluctuation regime before going to the Meissner phase at T=T.

  15. Properties of dipolar bosonic quantum gases at finite temperatures

    NASA Astrophysics Data System (ADS)

    Boudjemâa, Abdelâali

    2016-07-01

    The properties of ultracold quantum gases of bosons with dipole–dipole interaction are investigated at finite temperature in the frame of representative ensembles theory. Self-consistent coupled equations of motion are derived for the condensate and the non-condensate components. Corrections due to the dipolar interaction to condensate depletion, the anomalous density and thermodynamic quantities such as the ground state energy, the equation of state, the compressibility and the presure are calculated in the homogeneous case at both zero and finite temperatures. Effects of interaction and temperature on the structure factor are also discussed. Within the realm of the local density approximation, we generalize our results to the case of a trapped dipolar gas.

  16. Quantum degenerate atomic gases in controlled optical lattice potentials

    NASA Astrophysics Data System (ADS)

    Gemelke, Nathan D.

    2007-12-01

    Since the achievement of Bose Einstein condensation in cold atomic gases, mean-field treatments of the condensed phase have provided an excellent description for the static and dynamic properties observed in experiments. Recent experimental efforts have focused on studying deviations from mean-field behavior. I will describe work on two experiments which introduce controlled single particle degeneracies with time-dependent optical potentials, aiming to induce correlated motion and nontrivial statistics in the gas. In the first experiment, an optical lattice with locally rotating site potentials is produced to investigate fractional quantum Hall effects (FQHE) in rotating Bose gases. Here, the necessary gauge potential is provided by the rotating reference frame of the gas, which, in direct analogy to the electronic system, organizes single particle states into degenerate Landau levels. At low temperatures the repulsive interaction provided by elastic scattering is expected to produce ground states with structure nearly identical to those in the FQHE. I will discuss how these effects are made experimentally feasible by working at small particle numbers in the tight trapping potentials of an optical lattice, and present first results on the use of photoassociation to probe correlation in this system. In the second experiment, a vibrated optical lattice potential alters the single-particle dispersion underlying a condensed Bose gas and offers tailored phase-matching for nonlinear atom optical processes. I will demonstrate how this leads to parametric instability in the condensed gas, and draw analogy to an optical parametric oscillator operating above threshold.

  17. Quantum gases in trimerized kagomé lattices

    NASA Astrophysics Data System (ADS)

    Damski, B.; Fehrmann, H.; Everts, H.-U.; Baranov, M.; Santos, L.; Lewenstein, M.

    2005-11-01

    We study low-temperature properties of atomic gases in trimerized optical kagomé lattices. The laser arrangements that can be used to create these lattices are briefly described. We also present explicit results for the coupling constants of the generalized Hubbard models that can be realized in such lattices. In the case of a single-component Bose gas the existence of a Mott insulator phase with fractional numbers of particles per trimer is verified in a mean-field approach. The main emphasis of the paper is on an atomic spinless interacting Fermi gas in the trimerized kagomé lattice with two fermions per site. This system is shown to be described by a quantum spin- 1/2 model on the triangular lattice with couplings that depend on the bond directions. We investigate this model by means of exact diagonalization. Our key finding is that the system exhibits nonstandard properties of a quantum spin-liquid crystal: it combines planar antiferromagnetic order in the ground state with an exceptionally large number of low-energy excitations. The possibilities of experimental verification of our theoretical results are critically discussed.

  18. Ultracold quantum gases and lattice systems: quantum simulation of lattice gauge theories

    NASA Astrophysics Data System (ADS)

    Wiese, U.-J.

    2013-11-01

    Abelian and non-Abelian gauge theories are of central importance in many areas of physics. In condensed matter physics, Abelian U(1) lattice gauge theories arise in the description of certain quantum spin liquids. In quantum information theory, Kitaev's toric code is a Z(2) lattice gauge theory. In particle physics, Quantum Chromodynamics (QCD), the non-Abelian SU(3) gauge theory of the strong interactions between quarks and gluons, is non-perturbatively regularized on a lattice. Quantum link models extend the concept of lattice gauge theories beyond the Wilson formulation, and are well suited for both digital and analog quantum simulation using ultracold atomic gases in optical lattices. Since quantum simulators do not suffer from the notorious sign problem, they open the door to studies of the real-time evolution of strongly coupled quantum systems, which are impossible with classical simulation methods. A plethora of interesting lattice gauge theories suggests itself for quantum simulation, which should allow us to address very challenging problems, ranging from confinement and deconfinement, or chiral symmetry breaking and its restoration at finite baryon density, to color superconductivity and the real-time evolution of heavy-ion collisions, first in simpler model gauge theories and ultimately in QCD.

  19. Laser ultrasonic multi-component imaging

    DOEpatents

    Williams, Thomas K.; Telschow, Kenneth

    2011-01-25

    Techniques for ultrasonic determination of the interfacial relationship of multi-component systems are discussed. In implementations, a laser energy source may be used to excite a multi-component system including a first component and a second component at least in partial contact with the first component. Vibrations resulting from the excitation may be detected for correlation with a resonance pattern indicating if discontinuity exists at the interface of the first and second components.

  20. Negative specific heat with trapped ultracold quantum gases

    NASA Astrophysics Data System (ADS)

    Strzys, M. P.; Anglin, J. R.

    2014-01-01

    The second law of thermodynamics normally prescribes that heat tends to disperse, but in certain cases it instead implies that heat will spontaneously concentrate. The spontaneous formation of stars out of cold cosmic nebulae, without which the universe would be dark and dead, is an example of this phenomenon. Here we show that the counter-intuitive thermodynamics of spontaneous heat concentration can be studied experimentally with trapped quantum gases, by using optical lattice potentials to realize weakly coupled arrays of simple dynamical subsystems, so that under the standard assumptions of statistical mechanics, the behavior of the whole system can be predicted from ensemble properties of the isolated components. A naive application of the standard statistical mechanical formalism then identifies the subsystem excitations as heat in this case, but predicts them to share the peculiar property of self-gravitating protostars, of having negative micro-canonical specific heat. Numerical solution of real-time evolution equations confirms the spontaneous concentration of heat in such arrays, with initially dispersed energy condensing quickly into dense ‘droplets’. Analysis of the nonlinear dynamics in adiabatic terms allows it to be related to familiar modulational instabilities. The model thus provides an example of a dictionary mesoscopic system, in which the same non-trivial phenomenon can be understood in both thermodynamical and mechanical terms.

  1. Permanent magnetic lattices for ultracold atoms and quantum degenerate gases

    NASA Astrophysics Data System (ADS)

    Ghanbari, Saeed; Kieu, Tien D.; Sidorov, Andrei; Hannaford, Peter

    2006-02-01

    We propose the use of periodic arrays of permanent magnetic films for producing magnetic lattices of microtraps for confining, manipulating and controlling small clouds of ultracold atoms and quantum degenerate gases. Using analytical expressions and numerical calculations we show that periodic arrays of magnetic films can produce one-dimensional (1D) and two-dimensional (2D) magnetic lattices with non-zero potential minima, allowing ultracold atoms to be trapped without losses due to spin flips. In particular, we show that two crossed layers of periodic arrays of parallel rectangular magnets plus bias fields, or a single layer of periodic arrays of square-shaped magnets with three different thicknesses plus bias fields, can produce 2D magnetic lattices of microtraps having non-zero potential minima and controllable trap depth. For arrays with micron-scale periodicity, the magnetic microtraps can have very large trap depths (~0.5 mK for the realistic parameters chosen for the 2D lattice) and very tight confinement.

  2. Single atom detection in ultracold quantum gases: a review of current progress

    NASA Astrophysics Data System (ADS)

    Ott, Herwig

    2016-05-01

    The recent advances in single atom detection and manipulation in experiments with ultracold quantum gases are reviewed. The discussion starts with the basic principles of trapping, cooling and detecting single ions and atoms. The realization of single atom detection in ultracold quantum gases is presented in detail and the employed methods, which are based on light scattering, electron scattering, field ionization and direct neutral particle detection are discussed. The microscopic coherent manipulation of single atoms in a quantum gas is also covered. Various examples are given in order to highlight the power of these approaches to study many-body quantum systems.

  3. Single atom detection in ultracold quantum gases: a review of current progress.

    PubMed

    Ott, Herwig

    2016-05-01

    The recent advances in single atom detection and manipulation in experiments with ultracold quantum gases are reviewed. The discussion starts with the basic principles of trapping, cooling and detecting single ions and atoms. The realization of single atom detection in ultracold quantum gases is presented in detail and the employed methods, which are based on light scattering, electron scattering, field ionization and direct neutral particle detection are discussed. The microscopic coherent manipulation of single atoms in a quantum gas is also covered. Various examples are given in order to highlight the power of these approaches to study many-body quantum systems. PMID:27093632

  4. Noise limits in matter-wave interferometry using degenerate quantum gases

    SciTech Connect

    Search, Chris P.; Meystre, Pierre

    2003-06-01

    We analyze the phase resolution limit of a Mach-Zehnder atom interferometer whose input consists of degenerate quantum gases of either bosons or fermions. For degenerate gases, the number of atoms within one de Broglie wavelength is larger than unity, so that atom-atom interactions and quantum statistics are no longer negligible. We show that for equal atom numbers, the phase resolution achievable with fermions is noticeably better than for interacting bosons.

  5. Multi-Component Reactions in Heterocyclic Chemistry

    NASA Astrophysics Data System (ADS)

    Müller, Thomas J. J.; Orru, Romano V. A.; Chebanov, Valentin A.; Sakhno, Yana I.; Saraev, Vyacheslav E.; Muravyova, Elena A.; Andrushchenko, Anastasia Yu.; Desenko, Sergey M.; Akhmetova, V. R.; Khabibullina, G. R.; Rakhimova, E. B.; Vagapov, R. A.; Khairullina, R. R.; Niatshina, Z. T.; Murzakova, N. N.; Maslivets, Andrey N.; Voskressensky, Leonid G.; Danagulyan, Gevorg G.; Murtchyan, Armen D.; Tumanyan, Araksya K.; Banfi, Luca; Basso, Andrea; de Moliner, Fabio; Guanti, Giuseppe; Petricci, Elena; Riva, Renata; Taddei, Maurizio; Naimi-Jamal, M. Reza; Mashkouri, Sara; Sharifi, Ali; Przhevalski, Nikolai M.; Rozhkova, Elena N.; Tokmakov, Gennadii P.; Magedov, Igor V.; Armisheva, M. N.; Rassudihina, N. A.; Vahrin, M. I.; Gein, V. L.; Shaabani, Ahmad; Rezayan, Ali Hossein; Sarvary, Afshin; Heidary, Marjan; Ng, Seik Weng; Beliaev, Nikolai A.; Mokrushin, Vladimir S.; Paramonov, Igor V.; Ilyin, Alexey; Garkushenko, Anna K.; Dushek, Maria A.; Sagitullina, Galina P.; Sagitullin, Reva S.; Kysil, Volodymyr; Khvat, Alexander; Tsirulnikov, Sergey; Tkachenko, Sergey; Ivachtchenko, Alexandre; Gein, Vladimir L.; Panova, Olga S.; Ilyn, Alexey P.; Kravchenko, Dmitri V.; Potapov, Victor V.; Ivachtchenko, Alexandre V.; Vichegjanina, V. N.; Levandovskaya, E. B.; Gein, V. L.; Vahrin, M. I.; Vladimirov, I. N.; Zorina, A. A.; Nosova, N. V.; Gein, V. L.; Fedorova, O. V.; Vahrin, M. I.

    Multi-component and domino reactions are efficient and effective methods in the sustainable and diversity-oriented synthesis of heterocycles. In particular, transition metal-catalyzed multi-component sequences have recently gained considerable interest. Based upon the Sonogashira entry to alkynones, alkenones, and intermediate allenes, we have opened new avenues to the one-pot synthesis of numerous classes of heterocyclic frameworks in an MCR fashion. This methodological approach has now found various applications in one-pot syntheses of functional chromophores, pharmaceutically active compounds, and marine alkaloids and derivatives.

  6. Mesoscopic effects in quantum phases of ultracold quantum gases in optical lattices

    SciTech Connect

    Carr, L. D.; Schirmer, D. G.; Wall, M. L.; Brown, R. C.; Williams, J. E.; Clark, Charles W.

    2010-01-15

    We present a wide array of quantum measures on numerical solutions of one-dimensional Bose- and Fermi-Hubbard Hamiltonians for finite-size systems with open boundary conditions. Finite-size effects are highly relevant to ultracold quantum gases in optical lattices, where an external trap creates smaller effective regions in the form of the celebrated 'wedding cake' structure and the local density approximation is often not applicable. Specifically, for the Bose-Hubbard Hamiltonian we calculate number, quantum depletion, local von Neumann entropy, generalized entanglement or Q measure, fidelity, and fidelity susceptibility; for the Fermi-Hubbard Hamiltonian we also calculate the pairing correlations, magnetization, charge-density correlations, and antiferromagnetic structure factor. Our numerical method is imaginary time propagation via time-evolving block decimation. As part of our study we provide a careful comparison of canonical versus grand canonical ensembles and Gutzwiller versus entangled simulations. The most striking effect of finite size occurs for bosons: we observe a strong blurring of the tips of the Mott lobes accompanied by higher depletion, and show how the location of the first Mott lobe tip approaches the thermodynamic value as a function of system size.

  7. Mesoscopic effects in quantum phases of ultracold quantum gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Carr, L. D.; Wall, M. L.; Schirmer, D. G.; Brown, R. C.; Williams, J. E.; Clark, Charles W.

    2010-01-01

    We present a wide array of quantum measures on numerical solutions of one-dimensional Bose- and Fermi-Hubbard Hamiltonians for finite-size systems with open boundary conditions. Finite-size effects are highly relevant to ultracold quantum gases in optical lattices, where an external trap creates smaller effective regions in the form of the celebrated “wedding cake” structure and the local density approximation is often not applicable. Specifically, for the Bose-Hubbard Hamiltonian we calculate number, quantum depletion, local von Neumann entropy, generalized entanglement or Q measure, fidelity, and fidelity susceptibility; for the Fermi-Hubbard Hamiltonian we also calculate the pairing correlations, magnetization, charge-density correlations, and antiferromagnetic structure factor. Our numerical method is imaginary time propagation via time-evolving block decimation. As part of our study we provide a careful comparison of canonical versus grand canonical ensembles and Gutzwiller versus entangled simulations. The most striking effect of finite size occurs for bosons: we observe a strong blurring of the tips of the Mott lobes accompanied by higher depletion, and show how the location of the first Mott lobe tip approaches the thermodynamic value as a function of system size.

  8. Novel Reagents for Multi-Component Reactions

    NASA Astrophysics Data System (ADS)

    Wang, Yanguang; Basso, Andrea; Nenajdenko, Valentine G.; Gulevich, Anton V.; Krasavin, Mikhail; Bushkova, Ekaterina; Parchinsky, Vladislav; Banfi, Luca; Basso, Andrea; Cerulli, Valentina; Guanti, Giuseppe; Riva, Renata; Rozentsveig, Igor B.; Rozentsveig, Gulnur N.; Popov, Aleksandr V.; Serykh, Valeriy J.; Levkovskaya, Galina G.; Cao, Song; Shen, Li; Liu, Nianjin; Wu, Jingjing; Li, Lina; Qian, Xuhong; Chen, Xiaopeng; Wang, Hongbo; Feng, Jinwu; Wang, Yanguang; Lu, Ping; Heravi, Majid M.; Sadjadi, Samaheh; Kazemizadeh, Ali Reza; Ramazani, Ali; Kudyakova, Yulia S.; Goryaeva, Marina V.; Burgart, Yanina V.; Saloutin, Victor I.; Mossetti, Riccardo; Pirali, Tracey; Tron, Gian Cesare; Rozhkova, Yulia S.; Mayorova, Olga A.; Shklyaev, Yuriy V.; Zhdanko, Alexander G.; Nenajdenko, Valentine G.; Stryapunina, Olga G.; Plekhanova, Irina V.; Glushkov, Vladimir A.; Shklyaev, Yurii V.

    Ketenimines are a class of versatile and highly reactive intermediates that can participate in a variety of organic reactions, such as nucleophilic additions, radical additions, [2 + 2] and [2 + 4] cycloadditions, and sigmatropic rearrangements. In this presentation, we report on a series of multi-component reactions that involve a ketenimine intermediate. These reactions could furnish diverse heterocyclic compounds, including functionalized iminocoumarin, iminodihydroqunolines, iminothiochromens, pyrrolines, isoquinolines, pyridines, β-lactams, imino-1,2-dihydrocoumarins, and benzimidazoles.

  9. Quantum control of spin correlations in ultracold lattice gases

    NASA Astrophysics Data System (ADS)

    Hauke, P.; Sewell, R. J.; Mitchell, M. W.; Lewenstein, M.

    2013-02-01

    We describe a technique for the preparation of quantum spin correlations in a lattice gas of ultracold atoms using an atom-light interaction of the kind routinely employed in quantum spin polarization spectroscopy. Our method is based on entropic cooling via quantum nondemolition measurement and feedback, and allows the creation and detection of quantum spin correlations, as well as a certain degree of multipartite entanglement which we verify using a generalization of the entanglement witness described previously M. Cramer , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.106.020401 106, 020401 (2011). We illustrate the procedure with examples drawn from the bilinear-biquadratic Hamiltonian, which can be modeled by a one-dimensional chain of spin-1 atoms.

  10. Novel Quantum Phases of Dipolar Bose Gases in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Yi, S.; Li, T.; Sun, C. P.

    2007-06-01

    We investigate the quantum phases of polarized dipolar bosons loaded into a two-dimensional square and three-dimensional cubic optical lattices. We show that the long-range and anisotropic nature of the dipole-dipole interaction induces a rich variety of quantum phases, including the supersolid and striped supersolid phases in two-dimensional lattices, and the layered supersolid phase in three-dimensional lattices.

  11. Thermodynamics of quantum degenerate gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Blakie, P. B.; Rey, A.-M.; Bezett, A.

    2007-02-01

    The entropy-temperature curves are calculated for non-interacting Bose and Fermi gases in a 3D optical lattice. These curves facilitate understanding of how adiabatic changes in the lattice depth affect the temperature, and we demonstrate regimes where the atomic sample can be significantly heated or cooled by the loading process. We assess the effects of interactions on a Bose gas in a deep optical lattice, and show that interactions ultimately limit the extent of cooling that can occur during lattice loading.

  12. Isothermal-sweep theorems for ultracold quantum gases in a canonical ensemble

    NASA Astrophysics Data System (ADS)

    Iskin, M.

    2011-03-01

    After deriving the isothermal Hellmann-Feynman theorem (IHFT) that is suitable for mixed states in a canonical ensemble, we use this theorem to obtain the isothermal magnetic-field sweep theorems for the free, average, and trapping energies and for the entropy, specific heat, pressure, and atomic compressibility of strongly correlated ultracold quantum gases. In particular, we apply the sweep theorems to two-component Fermi gases in the weakly interacting Bardeen-Cooper-Schrieffer and Bose-Einstein condensate limits, showing that the temperature dependence of the contact parameter can be determined by varying either the entropy or specific heat with respect to the scattering length. We also use the IHFT to obtain the virial theorem in a canonical ensemble and discuss its implications for quantum gases.

  13. Quantum magnetism without lattices in strongly interacting one-dimensional spinor gases

    NASA Astrophysics Data System (ADS)

    Deuretzbacher, F.; Becker, D.; Bjerlin, J.; Reimann, S. M.; Santos, L.

    2014-07-01

    We show that strongly interacting multicomponent gases in one dimension realize an effective spin chain, offering an alternative simple scenario for the study of one-dimensional (1D) quantum magnetism in cold gases in the absence of an optical lattice. The spin-chain model allows for an intuitive understanding of recent experiments and for a simple calculation of relevant observables. We analyze the adiabatic preparation of antiferromagnetic and ferromagnetic ground states, and show that many-body spin states may be efficiently probed in tunneling experiments. The spin-chain model is valid for more than two components, opening the possibility of realizing SU(N) quantum magnetism in strongly interacting 1D alkaline-earth-metal or ytterbium Fermi gases.

  14. N-soliton statistics and condensate formation in dense quantum gases

    NASA Astrophysics Data System (ADS)

    Mirza, Babur M.

    2014-09-01

    Statistics of N quantum density soliton waves [B. M. Mirza, Mod. Phys. Lett. B28 (2014) 1450148] is extended here to the case of systems with symmetric wave function. Since many such systems exhibit condensation phenomena, application is made of the soliton wave statistics to investigate condensation and phase transition in quantum gases such as 4He and also dense systems such as the alkali atoms. Specific heat discontinuities are used to determine the condensation temperature for dense quantum gases and liquids. For the model case of helium the statistical theory is shown to predict not only the observed superfluid condensation temperature (2.17 ± 0.01 K) correctly but also the normal condensation temperature (4.21 ± 0.02 K), as well as the exact specific heat λ-profile.

  15. Design of Multi-Component Reactions

    NASA Astrophysics Data System (ADS)

    Zhu, Jieping; Kaïm, Laurent El; Tron, Gian Cesare; Lavilla, Rodolfo; Banfi, Luca; Basso, Andrea; Cerulli, Valentina; Guanti, Giuseppe; Lecinska, Paulina; Riva, Renata; Arévalo, M. J.; Kielland, N.; Masdeu, C.; Miguel, M.; Isambert, N.; Lavilla, R.; Medvedeva, Alevtina S.; Novokshonov, Vladimir V.; Novokshonova, Irina A.; Demina, Maria M.; Kon'kova, Tatyana V.; Shklyaev, Yurii V.; Rozhkova, Yulia S.; Vshivkova, Tatiana S.; Stryapunina, Olga G.; Glushkov, Vladimir A.; Kharitonova, Anastasia V.; Fisyuk, Alexander S.; Mukanov, Aleksey Y.; Poendaev, Nicolay V.; Gulevich, Anton V.; Nenajdenko, Valentine G.; Ivantsova, Maria N.; Tokareva, Maria I.; Mironov, Maxim A.; Mokrushin, Vladimir S.; Pirali, Tracey; Tron, Gian Cesare; Zhu, Jieping; Rozentsveig, Igor B.; Popov, Aleksandr V.; Levkovskaya, Galina G.; Chernyshev, Kirill A.; Krivdin, Leonid B.; Tomilov, Yury V.; Platonov, Dmitry N.; Rulev, Alexander Y.; Ushakov, Igor A.; Vorobyeva, Alexandra; Ilyin, Alexey; Kysil, Volodimir; Ivachtchenko, Alexandre

    Multi-component reactions (MCRs) have now been well established as a powerful synthetic tool for creating molecular complexity and diversity and are undoubtedly well suited for the drug discovery program. Another potential that has probably received less attention among synthetic chemists is the opportunity offered by MCRs for the development of new fundamentally important transformations (reactions). Indeed, although an MCR is composed of a series of known bimolecular reactions, the overall transformation could be novel. Consequently, it provides chemists the opportunities to uncover transformations that were otherwise difficult to realize. In this talk, we will present our recent work in this field, including: (1) the oxidative homologation of aldehydes to amides, (2) the oxidative coupling of aldehydes and isocyanides to α-ketoamides, (3) oxidative isocyanide-based MCRs, and (4) the enantioselective Passerini reaction.

  16. Quantum phases of quadrupolar Fermi gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Bhongale, Satyan; Mathey, Ludwig; Zhao, Erhai; Yellin, Susanne; Lemeshko, Mikhail

    2013-05-01

    We introduce a new platform for quantum simulation of many-body systems based on nonspherical atoms or molecules with zero dipole moment but possessing a significant value of electric quadrupole moment. We consider a quadrupolar Fermi gas trapped in a 2D square optical lattice, and show that the peculiar symmetry and broad tunability of the quadrupole-quadrupole interaction results in a rich phase diagram encompassing unconventional BCS and charge density wave phases, and opens up a perspective to create topological superfluid. Quadrupolar species, such as metastable alkaline-earth atoms and homonuclear molecules, are stable against chemical reactions and collapse and are readily available in experiment at high densities.

  17. Quantum Phases of Quadrupolar Fermi Gases in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Bhongale, S. G.; Mathey, L.; Zhao, Erhai; Yelin, S. F.; Lemeshko, Mikhail

    2013-04-01

    We introduce a new platform for quantum simulation of many-body systems based on nonspherical atoms or molecules with zero dipole moments but possessing a significant value of electric quadrupole moments. We consider a quadrupolar Fermi gas trapped in a 2D square optical lattice, and show that the peculiar symmetry and broad tunability of the quadrupole-quadrupole interaction results in a rich phase diagram encompassing unconventional BCS and charge density wave phases, and opens up a perspective to create a topological superfluid. Quadrupolar species, such as metastable alkaline-earth atoms and homonuclear molecules, are stable against chemical reactions and collapse and are readily available in experiment at high densities.

  18. Permutation-symmetry related selection rules in spinor quantum gases

    NASA Astrophysics Data System (ADS)

    Yurovsky, Vladimir

    2014-05-01

    Selection rules constraining possible transitions between states of quantum systems can be derived from the system symmetry. Invariance over permutations of indistinguishable particles, contained in each physical system, is one of the basic symmetries. Consider a many-body system with separable spin and spatial degrees of freedom of particles with arbitrary spins s. Eigenfunctions of such systems can be expressed as a sum of products of spin and spatial functions, which form irreducible representations (irreps) of the symmetric group. The quantum numbers are the Young diagrams λ = [λ1 , ... ,λ2 s + 1 ] . The selection rules for a general k-body interactions allow transitions between the states λ and λ' only if ∑m=12s+1 |λm -λm'| <= 2 k . For s = 1 / 2 , the Young diagrams are unambiguously related to the total spin, and if k = 1 , we get the conventional selection rule for dipole transitions. However, if s > 1 / 2 , the rules cannot be expressed in terms of spins. The selection rules provide a way of control over the formation of many-body entangled states, belonging to multidimensional, non-Abelian irreps of the symmetric group. The effects can be observed with spinor atoms in an optical lattice in the Mott-insulator regime.

  19. Photoassociation experiments on ultracold and quantum gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Ryu, Changhyun

    This thesis describes the results of several experiments that studied the photoassociation of an ultracold atomic Rb gas. In the first experiment, we produced ultracold diatomic molecules from an atomic gas via single-color photoassociation. The molecules were detected with resonance-enhanced multiphoton ionization. Trapping of these molecules in a quadrupole magnetic trap, with lifetimes up to 20 seconds, was also demonstrated. In addition, the rate constant for inelastic collisions between the trapped molecules and atoms was determined from measurements of the atomic density dependence of the decay rate of the trapped molecules. In another experiment, stimulated Raman photoassociation of Rb atoms in a Mott insulator state was studied. A Bose-Einstein condensate (BEC) of 87Rb atoms was loaded into a three-dimensional optical lattice formed by the interference pattern of three orthogonal standing wave laser fields. This system constitutes a very good realization of the Bose-Hubbard model; which predicts a quantum phase transition between a superfluid state and a Mott insulator state at a particular lattice height. A time-of-flight imaging method was used to study the state of the atomic gas, and the quantum phase transition was observed at the predicted lattice height. The signature of the phase transition was the disappearance and reappearance of peaks in the image that arose from the interference of atoms originating from different lattice sites. Two coherent laser fields were applied to the gas in its Mott insulating state, and tuned close to a Raman photoassociation resonance, and this resulted in an observable loss of atoms due to the formation of molecules. This transition exhibited a double-peaked spectrum, with one of the peaks arising from photoassociation of atoms in sites containing only two atoms, and the other from sites containing three atoms. Also, the loss of atoms vs. the duration of the Raman photoassociation period was studied, with the lasers

  20. The SQCRAMscope: Probing exotic materials with quantum gases

    NASA Astrophysics Data System (ADS)

    Qiao, Shenglan; Turner, Richard; Disciacca, Jack; Lev, Benjamin

    2015-03-01

    Microscopy techniques co-opted from nonlinear optics and high energy physics have complemented solid-state probes in elucidating exotic order manifest in condensed matter materials. Up until now, however, no attempts have been made to use modern techniques of ultracold atomic physics to directly explore properties of strongly correlated or topologically protected materials. Our talk will present the SQCRAMscope, a novel Scanning Quantum CRyogenic Atom Microscope technique for imaging magnetic and electric fields near cryogenically cooled materials. With our SQCRAMscope, we aim to image inhomogeneous transport and domain percolation in technologically relevant materials whose order has evaded elucidation. We are grateful to the Moore Foundation and the Department of Energy for their generous support.

  1. Quantum phases of quadrupolar Fermi gases in optical lattices.

    PubMed

    Bhongale, S G; Mathey, L; Zhao, Erhai; Yelin, S F; Lemeshko, Mikhail

    2013-04-12

    We introduce a new platform for quantum simulation of many-body systems based on nonspherical atoms or molecules with zero dipole moments but possessing a significant value of electric quadrupole moments. We consider a quadrupolar Fermi gas trapped in a 2D square optical lattice, and show that the peculiar symmetry and broad tunability of the quadrupole-quadrupole interaction results in a rich phase diagram encompassing unconventional BCS and charge density wave phases, and opens up a perspective to create a topological superfluid. Quadrupolar species, such as metastable alkaline-earth atoms and homonuclear molecules, are stable against chemical reactions and collapse and are readily available in experiment at high densities. PMID:25167282

  2. Atomic and molecular quantum gases in an optical lattice

    NASA Astrophysics Data System (ADS)

    Hecker Denschlag, Johannes

    2007-06-01

    We report on recent progress in preparing and manipulating ultracold atomic and molecular ensembles in a 3D optical lattice. Starting from an atomic ^87Rb condensate which is adiabatically loaded into a 3D optical lattice we can control the state and dynamics of the gas on the quantum level with the help of static magnetic fields, radio-frequency and laser radiation and a Feshbach resonance. For example, we can produce a pure molecular ensemble of Rb2 Feshbach molecules in the lattice [1] and can coherently transfer it to a more deeply molecular bound state via STIRAP [2] or radio-frequency transitions. Besides possible applications for investigating molecular collisions and producing ultracold molecules in the vibrational ground state, this can also be used for spectroscopic precision measurements of molecular levels. Besides studying chemically bound molecules, optical lattices also allow for forming a novel kind of stable bound state of two atoms which is based on repulsion rather than attraction between the particles [3]. We will explain how these lattice-induced repulsively bound atom pairs come about and discuss their interesting properties. [1] G. Thalhammer et al., Phys. Rev. Lett. 96, 050402 (2006). [2] K. Winkler, cond-mat/0611222 [3] K. Winkler et al., Nature 441, 853, (2006).

  3. Scale-Invariant Hydrodynamics and Quantum Viscosity in Fermi Gases

    NASA Astrophysics Data System (ADS)

    Thomas, John

    2015-05-01

    An optically-trapped gas of spin 1/2-up and spin 1/2-down 6Li atoms, tuned near a collisional (Feshbach) resonance, provides a unique paradigm for testing predictions that cross interdisciplinary boundaries, from high temperature superconductors to nuclear matter. At resonance, the dilute atomic cloud becomes the most strongly interacting, non-relativistic fluid known: Shock waves are produced when two clouds collide. We observe scale-invariant hydrodynamic expansion of a resonantly interacting gas and determine the quantum shear viscosity η = α ℏn , with n the density, as a function of interaction strength and temperature, from nearly the ground state through the superfluid phase transition. We extract the local shear viscosity coefficient α from cloud-averaged data, using iterative methods borrowed from image processing, and observe previously hidden features, which are compared to recent predictions. In collaboration with Ethan Elliott and James Joseph, Physics Department, North Carolina State University. Supported by NSF, DOE, ARO, AFOSR.

  4. Topological phases and polaron physics in ultracold quantum gases

    NASA Astrophysics Data System (ADS)

    Grusdt, Fabian

    2016-05-01

    The description of quantum many-body systems poses a formidable theoretical challenge. A seemingly simple problem is the coupling of a single impurity atom to non-interacting Bogoliubov phonons in a surrounding Bose-Einstein condensate. The system can be described by a polaron model at intermediate couplings - an 80 year problem. The situation has been realized experimentally, but when the impurity mass is small compared to the Boson mass, neither mean-field nor strong-coupling expansions are valid anymore. Now the impurity acts as an exchange particle, mediating phonon-phonon interactions. In this talk I present a semi-analytical solution to the polaron problem. I will show that the approach can be generalized to solve far-from equilibrium polaron problems, too, and elaborate on connections with recent experiments involving ultracold atoms and photons. A completely different class of many-body problems are systems with topological order. In recent years we have seen an uprise of cold-atomic or photonic implementations of artificial gauge fields, providing a corner stone for the realization of topological phases of matter. In the second part of my talk, I will address the challenging problem how non-local topological orders can be detected. It will be demonstrated that many-body topological invariants can be measured, making use of mobile impurities as coherent probes of the highly entangled groundstates. I will discuss Laughlin states and comment on possible realizations using ultracold atoms.

  5. Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment

    NASA Astrophysics Data System (ADS)

    Williams, Jason; D'Incao, Jose; Chiow, Sheng-Wey; Yu, Nan

    2015-05-01

    Precision atom interferometers (AI) in space promise exciting technical capabilities for fundamental physics research, with proposals including unprecedented tests of the weak equivalence principle, precision measurements of the fine structure and gravitational constants, and detection of gravity waves and dark energy. Consequently, multiple AI-based missions have been proposed to NASA, including a dual-atomic-species interferometer that is to be integrated into the Cold Atom Laboratory (CAL) onboard the International Space Station. In this talk, I will discuss our plans and preparation at JPL for the proposed flight experiments to use the CAL facility to study the leading-order systematics expected to corrupt future high-precision measurements of fundamental physics with AIs in microgravity. The project centers on the physics of pairwise interactions and molecular dynamics in these quantum systems as a means to overcome uncontrolled shifts associated with the gravity gradient and few-particle collisions. We will further utilize the CAL AI for proof-of-principle tests of systematic mitigation and phase-readout techniques for use in the next-generation of precision metrology experiments based on AIs in microgravity. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  6. Single Pass Multi-component Harvester

    SciTech Connect

    Reed Hoskinson; J. Richard Hess

    2004-08-01

    Abstract. In order to meet the U. S. government’s goal of supplementing the energy available from petroleum by increasing the production of energy from renewable resources, increased production of bioenergy has become one of the new goals of the United States government and our society. U.S. Executive Orders and new Federal Legislation have mandated changes in government procedures and caused reorganizations within the government to support these goals. The Biomass Research and Development Initiative is a multi-agency effort to coordinate and accelerate all U.S. Federal biobased products and bioenergy research and development. The Initiative is managed by the National Biomass Coordination Office, which is staffed by both the DOE and the USDA. One of the most readily available sources of biomass from which to produce bioenergy is an agricultural crop residue, of which straw from small grains is the most feasible residue with which to start. For the straw residue to be used its collection must be energy efficient and its removal must not impact the sustainability of the growing environment. In addition, its collection must be economically advantageous to the producer. To do all that, a single pass multi-component harvester system is most desirable. Results from our first prototype suggest that current combines probably do adequate threshing and that a separate chassis can be developed that does additional separation and that is economically feasible.

  7. Effective p -wave interaction and topological superfluids in s -wave quantum gases

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Zheng, Zhen; Pu, Han; Zou, Xubo; Guo, Guangcan

    2016-03-01

    p -wave interaction in cold atoms may give rise to exotic topological superfluids. However, the realization of p -wave interaction in a cold atom system is experimentally challenging. Here we propose a simple scheme to synthesize effective p -wave interaction in conventional s -wave interacting quantum gases. The key idea is to load atoms into a spin-dependent optical lattice potential. Using two concrete examples involving spin-1/2 fermions, we show how the original system can be mapped into a model describing spinless fermions with nearest-neighbor p -wave interaction, whose ground state can be a topological superfluid that supports Majorana fermions under proper conditions. Our proposal has the advantage that it does not require spin-orbit coupling or loading atoms onto higher orbitals, which is the key in earlier proposals to synthesize effective p -wave interaction in s -wave quantum gases, and may provide a completely new route for realizing p -wave topological superfluids.

  8. Lattice Uehling-Uhlenbeck Boltzmann-Bhatnagar-Gross-Krook hydrodynamics of quantum gases

    NASA Astrophysics Data System (ADS)

    Yang, Jaw-Yen; Hung, Li-Hsin

    2009-05-01

    We present a semiclassical lattice Boltzmann method based on quantum kinetic theory. The method is directly derived by projecting the Uehling-Uhlenbeck Boltzmann-Bhatnagar-Gross-Krook equations onto the tensor Hermite polynomials following Grad’s moment expansion method. The intrinsic discrete nodes of the Gauss-Hermite quadrature provide the natural lattice velocities for the semiclassical lattice Boltzmann method. Gases of particles of arbitrary statistics can be considered. Simulation of one-dimensional compressible gas flow and two-dimensional hydrodynamic flows are shown. The results indicate distinct characteristics of the effects of quantum statistics.

  9. Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases

    NASA Astrophysics Data System (ADS)

    He, Lianyi; Lü, Haifeng; Cao, Gaoqing; Hu, Hui; Liu, Xia-Ji

    2015-08-01

    We present a theoretical study of the ground state of the BCS-BEC crossover in dilute two-dimensional Fermi gases. While the mean-field theory provides a simple and analytical equation of state, the pressure is equal to that of a noninteracting Fermi gas in the entire BCS-BEC crossover, which is not consistent with the features of a weakly interacting Bose condensate in the BEC limit and a weakly interacting Fermi liquid in the BCS limit. The inadequacy of the two-dimensional mean-field theory indicates that the quantum fluctuations are much more pronounced than those in three dimensions. In this work, we show that the inclusion of the Gaussian quantum fluctuations naturally recovers the above features in both the BEC and the BCS limits. In the BEC limit, the missing logarithmic dependence on the boson chemical potential is recovered by the quantum fluctuations. Near the quantum phase transition from the vacuum to the BEC phase, we compare our equation of state with the known grand canonical equation of state of two-dimensional Bose gases and determine the ratio of the composite boson scattering length aB to the fermion scattering length a2 D. We find aB≃0.56 a2 D , in good agreement with the exact four-body calculation. We compare our equation of state in the BCS-BEC crossover with recent results from the quantum Monte Carlo simulations and the experimental measurements and find good agreements.

  10. Nonlinear spectroscopic effects in quantum gases induced by atom-atom interactions

    SciTech Connect

    Safonov, A. I. Safonova, I. I.; Yasnikov, I. S.

    2013-05-15

    We consider nonlinear spectroscopic effects-interaction-enhanced double resonance and spectrum instability-that appear in ultracold quantum gases owing to collisional frequency shift of atomic transitions and, consequently, due to the dependence of the frequencies on the population of various internal states of the particles. Special emphasis is put to two simplest cases, (a) the gas of two-level atoms and (b) double resonance in a gas of three-level bosons, in which the probe transition frequency remains constant.

  11. Quantum gases in optical lattices : the atomic Mott insulator

    NASA Astrophysics Data System (ADS)

    van Oosten, D.

    2004-09-01

    An optical lattice is a periodic potential for atoms, created using a standing wave pattern of light. Due to the interaction between the light and the atoms, the atoms are attracted to either the nodes or the anti-nodes of the standing wave, depending on the exact wave lenght of the light. This means that if such a lattice is loaded with a sufficiently high number of ultracold atoms, a periodic array of atoms is obtained, we an interatomic distance of a few tenths of a micrometer. In order to obtain such a high number of cold atoms, one first has to create a so-called Bose-Einstein condensate. When an optical lattice is loaded from a Bose-Einstein condensate, it is possible to create a system in which every atom is in the lowest band of the lattice and there is on average one atom in each lattice site. Because the lattice potential is created with laser light, the depth of the lattice can easily be tuned by changing the intensity of the laser. When the intensity of the laser light is low, the atoms can tunnel from one site to the next. Due to this tunneling, the gas of atoms in the lattice will remain superfluid. However, if the intensity of the laser light is increased to above a certain critical value, a quantum phase transition occurs to a so-called Mott insulator. In this state, the atoms can no longer tunnel due to the fact that the on-site interaction between atoms becomes more important then the tunneling probability. In this PhD thesis, a description is given of the experimental setup that is being constructed in our group to create these systems in our lab. Also, a theoretical description is given of these systems and several important quantities our derived, such as the gap of the Mott-insulating state. Furthermore, an experiment is proposed that can be used to accurately measure this gap.

  12. Prediction of the expansion velocity of ultracold 1D quantum gases for integrable models

    NASA Astrophysics Data System (ADS)

    Mei, Zhongtao; Vidmar, Lev; Heidrich-Meisner, Fabian; Bolech, Carlos

    In the theory of Bethe-ansatz integrable quantum systems, rapidities play an important role as they are used to specify many-body states. The physical interpretation of rapidities going back to Sutherland is that they are the asymptotic momenta after letting a quantum gas expand into a larger volume rendering it dilute and noninteracting. We exploit this picture to calculate the expansion velocity of a one-dimensional Fermi-Hubbard model by using the distribution of rapidities defined by the initial state. Our results are consistent with the ones from time-dependent density-matrix renormalization. We show in addition that an approximate Bethe-ansatz solution works well also for the Bose-Hubbard model. Our results are of interests for future sudden-expansion experiments with ultracold quantum gases.

  13. The macroscopic quantum phase of ultracold degenerate gases in the asymmetrical two-dimensional magnetic lattice

    NASA Astrophysics Data System (ADS)

    Abdelrahman, A.; Vasiliev, M.; Alameh, K.

    2011-06-01

    We investigate the existence of the macroscopic quantum phase in trapped ultracold quantum degenerate gases in an asymmetrical two-dimensional magnetic lattice. We show the key to adiabatically control the tunneling in the new two-dimensional magnetic lattice by means of external magnetic bias fields. In solving the system of coupled time-dependent differential equations, described here by the Boson Josephson Junctions (BJJs), we used an order parameter that includes both time-dependent variational parameters to describe the fractional population at each lattice site and the phase difference to quantify the macroscopic quantum phase signature. A dynamical oscillation of the fractional population and the phase difference at each individual lattice site is observed when solving the BJJs system.

  14. The Single Pass Multi-component Harvester

    SciTech Connect

    Reed Hoskinson; John R. Hess

    2004-08-01

    collection must be economically advantageous to the producer. To do all that, a single pass multi-component harvester system is most desirable. Results from our first prototype suggest that current combines probably do adequate threshing and that a separate chassis can be developed that does additional separation and that is economically feasible.

  15. An Experimental Apparatus for Studying Rydberg-Rydberg Interactions in Quantum Degenerate Gases of Strontium

    NASA Astrophysics Data System (ADS)

    Camargo, Francisco; Ding, Roger; Aman, James; Zhang, Xinyue; Whalen, Joseph; Fields, Robert; Dunning, F. Barry; Killian, Thomas

    2014-05-01

    We discuss the design and construction of a new apparatus for creating and studying long-range interactions in ultracold gases of strontium by exploiting Rydberg states, either through their direct excitation or through laser-induced Rydberg dressing. Strontium features one fermionic (87Sr) and three bosonic (84Sr, 86Sr, 88Sr) isotopes, all of which have been brought to quantum degeneracy. It also possesses singlet and triplet Rydberg states that furnish a wide variety of attractive and repulsive interactions. Furthermore, strontium Rydberg atoms feature an optically active core electron which can be used to manipulate and detect Rydberg atoms. These features make strontium a promising system for studying interactions in ultracold Rydberg gases. Research supported by Rice University, the NSF, the AFOSR, Shell, and the Robert A. Welch Foundation.

  16. Quantum phases of Bose gases on a lattice with pair-tunneling

    NASA Astrophysics Data System (ADS)

    Wang, Yue-Ming; Liang, Jiu-Qing

    2012-06-01

    We investigate the strongly interacting lattice Bose gases on a lattice with two-body interaction of nearest neighbors characterized by pair tunneling. The excitation spectrum and the depletion of the condensate of lattice Bose gases are investigated using the Bogoliubov transformation method and the results show that there is a pair condensate as well as a single particle condensate. The various possible quantum phases, such as the Mott-insulator phase (MI), the superfluid phase (SF) of an individual atom, the charge density wave phase (CDW), the supersolid phase (SS), the pair-superfluid (PSF) phase, and the pair-supersolid phase (PSS) are discussed in different parametric regions within our extended Bose-Hubbard model using perturbation theory.

  17. Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases

    DOE PAGESBeta

    He, Lianyi; Lu, Haifeng; Cao, Gaoqing; Hu, Hui; Liu, Xia -Ji

    2015-08-14

    We present a theoretical study of the ground state of the BCS-BEC crossover in dilute two-dimensional Fermi gases. While the mean-field theory provides a simple and analytical equation of state, the pressure is equal to that of a noninteracting Fermi gas in the entire BCS-BEC crossover, which is not consistent with the features of a weakly interacting Bose condensate in the BEC limit and a weakly interacting Fermi liquid in the BCS limit. The inadequacy of the two-dimensional mean-field theory indicates that the quantum fluctuations are much more pronounced than those in three dimensions. In this work, we show thatmore » the inclusion of the Gaussian quantum fluctuations naturally recovers the above features in both the BEC and the BCS limits. In the BEC limit, the missing logarithmic dependence on the boson chemical potential is recovered by the quantum fluctuations. Near the quantum phase transition from the vacuum to the BEC phase, we compare our equation of state with the known grand canonical equation of state of two-dimensional Bose gases and determine the ratio of the composite boson scattering length aB to the fermion scattering length a2D. We find aB ≃ 0.56a2D, in good agreement with the exact four-body calculation. As a result, we compare our equation of state in the BCS-BEC crossover with recent results from the quantum Monte Carlo simulations and the experimental measurements and find good agreements.« less

  18. Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases

    SciTech Connect

    He, Lianyi; Lu, Haifeng; Cao, Gaoqing; Hu, Hui; Liu, Xia -Ji

    2015-08-14

    We present a theoretical study of the ground state of the BCS-BEC crossover in dilute two-dimensional Fermi gases. While the mean-field theory provides a simple and analytical equation of state, the pressure is equal to that of a noninteracting Fermi gas in the entire BCS-BEC crossover, which is not consistent with the features of a weakly interacting Bose condensate in the BEC limit and a weakly interacting Fermi liquid in the BCS limit. The inadequacy of the two-dimensional mean-field theory indicates that the quantum fluctuations are much more pronounced than those in three dimensions. In this work, we show that the inclusion of the Gaussian quantum fluctuations naturally recovers the above features in both the BEC and the BCS limits. In the BEC limit, the missing logarithmic dependence on the boson chemical potential is recovered by the quantum fluctuations. Near the quantum phase transition from the vacuum to the BEC phase, we compare our equation of state with the known grand canonical equation of state of two-dimensional Bose gases and determine the ratio of the composite boson scattering length aB to the fermion scattering length a2D. We find aB ≃ 0.56a2D, in good agreement with the exact four-body calculation. As a result, we compare our equation of state in the BCS-BEC crossover with recent results from the quantum Monte Carlo simulations and the experimental measurements and find good agreements.

  19. Exploring the nonequilibrium dynamics of ultracold quantum gases by using numerical tools

    NASA Astrophysics Data System (ADS)

    Heidrich-Meisner, Fabian

    Numerical tools such as exact diagonalization or the density matrix renormalization group method have been vital for the study of the nonequilibrium dynamics of strongly correlated many-body systems. Moreover, they provided unique insight for the interpretation of quantum gas experiments, whenever a direct comparison with theory is possible. By considering the example of the experiment by Ronzheimer et al., in which both an interaction quench and the release of bosons from a trap into an empty optical lattice (sudden expansion) was realized, I discuss several nonequilibrium effects of strongly interacting quantum gases. These include the thermalization of a closed quantum system and its connection to the eigenstate thermalization hypothesis, nonequilibrium mass transport, dynamical fermionization, and transient phenomena such as quantum distillation or dynamical quasicondensation. I highlight the role of integrability in giving rise to ballistic transport in strongly interacting 1D systems and in determining the asymptotic state after a quantum quench. The talk concludes with a perspective on open questions concerning 2D systems and the numerical simulation of their nonequilibrium dynamics. Supported by Deutsche Forschungsgemeinschaft (DFG) via FOR 801.

  20. Gaussian potentials facilitate access to quantum Hall states in rotating Bose gases.

    PubMed

    Morris, Alexis G; Feder, David L

    2007-12-14

    Through exact numerical diagonalization for small numbers of atoms, we show that it is possible to access quantum Hall states in harmonically confined Bose gases at rotation frequencies well below the centrifugal limit by applying a repulsive Gaussian potential at the trap center. The main idea is to reduce or eliminate the effective trapping frequency in regions where the particle density is appreciable. The critical rotation frequency required to obtain the bosonic Laughlin state can be fixed at an experimentally accessible value by choosing an applied Gaussian whose amplitude increases linearly with the number of atoms while its width increases as the square root. PMID:18233424

  1. Path-integral calculation of the third virial coefficient of quantum gases at low temperatures

    SciTech Connect

    Garberoglio, Giovanni; Harvey, Allan H.

    2011-04-07

    We derive path-integral expressions for the second and third virial coefficients of monatomic quantum gases. Unlike previous work that considered only Boltzmann statistics, we include exchange effects (Bose-Einstein or Fermi-Dirac statistics). We use state-of-the-art pair and three-body potentials to calculate the third virial coefficient of {sup 3}He and {sup 4}He in the temperature range 2.6-24.5561 K. We obtain uncertainties smaller than those of the limited experimental data. Inclusion of exchange effects is necessary to obtain accurate results below about 7 K.

  2. Alkali-metal gases in optical lattices: Possible new type of quantum crystals

    NASA Astrophysics Data System (ADS)

    Meyerovich, A. E.

    2003-11-01

    Similarities between alkali-metal gases in optical lattices with noninteger occupation of the lattice sites and quantum crystals are explored. The analogy with the vacancy liquid (VL) provides an alternative explanation to the Mott transition for the recent experiment on the phase transition in the lattice. The VL can undergo Bose-Einstein condensation (BEC) with Tc within experimental reach. Direct and vacancy-assisted mechanisms of the band motion for hyperfine impurities are discussed. A large concentration of vacancies can result in the spatial decomposition of the system into pure hyperfine components. Below the vacancy condensation the impurity component resembles 3He in 3He He II mixtures.

  3. The Luttinger liquid in superlattice structures: atomic gases, quantum dots and the classical Ising chain

    NASA Astrophysics Data System (ADS)

    Bhattacherjee, Aranya B.; Jha, Pradip; Kumar, Tarun; Mohan, Man

    2011-01-01

    We study the physical properties of a Luttinger liquid in a superlattice that is characterized by alternating two tunneling parameters. Using the bosonization approach, we describe the corresponding Hubbard model by the equivalent Tomonaga-Luttinger model. We analyze the spin-charge separation and transport properties of the superlattice system. We suggest that cold Fermi gases trapped in a bichromatic optical lattice and coupled quantum dots offer the opportunity to measure these effects in a convenient manner. We also study the classical Ising chain with two tunneling parameters. We find that the classical two-point correlator decreases as the difference between the two tunneling parameters increases.

  4. Frictionless quantum quenches in ultracold gases: A quantum-dynamical microscope

    SciTech Connect

    Campo, A. de

    2011-09-15

    In this Rapid Communication, a method is proposed to spatially scale up a trapped ultracold gas while conserving the quantum correlations of the initial many-body state. For systems supporting self-similar dynamics, this is achieved by implementing an engineered finite-time quench of the harmonic trap, which induces a frictionless expansion of the gas and acts as a quantum dynamical microscope.

  5. Tunable defect interactions and supersolidity in dipolar quantum gases on a lattice potential

    NASA Astrophysics Data System (ADS)

    Lechner, Wolfgang; Cinti, Fabio; Pupillo, Guido

    2015-11-01

    Point defects in self-assembled crystals, such as vacancies and interstitials, attract each other and form stable clusters. This leads to a phase separation between perfect crystalline structures and defect conglomerates at low temperatures. We propose a method that allows one to tune the effective interactions between point defects from attractive to repulsive by means of external periodic fields. In the quantum regime, this allows one to engineer strongly correlated many-body phases. We exemplify the microscopic mechanism by considering dipolar quantum gases of ground-state polar molecules and weakly bound molecules of strongly magnetic atoms trapped in a weak optical lattice in a two-dimensional configuration. By tuning the lattice depth, defect interactions turn repulsive, which allows us to deterministically design a novel supersolid phase in the continuum limit.

  6. MPH: A library for distributed multi-component environment

    SciTech Connect

    Ding, Chris H.Q.; He, Yun

    2001-06-01

    Many current large and complex HPC applications are based on semi-independent program components developed by different groups or for different purposes. On distributed memory parallel supercomputers, how to perform component-name registration and initialize communications between independent components are among the first critical steps in establishing a distributed multi-component environment. Here we describe MPH, a multi-component handshaking library that resolves these tasks in a convenient and consistent way. MPH uses MPI for high performance and supports many PVM functionality. It supports two major parallel integration mechanism: multi-component multi-executable (MCME) and multi-component single-executable (MCME). It is a simple, easy-to-use module for developing practical codes, or as basis for larger software tools/frameworks.

  7. Quantum Hall states of atomic Bose gases: Density profiles in single-layer and multilayer geometries

    SciTech Connect

    Cooper, N. R.; Lankvelt, F. J. M. van; Reijnders, J. W.; Schoutens, K.

    2005-12-15

    We describe the density profiles of confined atomic Bose gases in the high-rotation limit, in single-layer and multilayer geometries. We show that, in a local-density approximation, the density in a single layer shows a landscape of quantized steps due to the formation of incompressible liquids, which are analogous to fractional quantum Hall liquids for a two-dimensional electron gas in a strong magnetic field. In a multilayered setup we find different phases, depending on the strength of the interlayer tunneling t. We discuss the situation where a vortex lattice in the three-dimensional condensate (at large tunneling) undergoes quantum melting at a critical tunneling t{sub c{sub 1}}. For tunneling well below t{sub c{sub 1}} one expects weakly coupled or isolated layers, each exhibiting a landscape of quantum Hall liquids. After expansion, this gives a radial density distribution with characteristic features (cusps) that provide experimental signatures of the quantum Hall liquids.

  8. Modulated decay in the multi-component Universe

    SciTech Connect

    Enomoto, Seishi; Kohri, Kazunori; Matsuda, Tomohiro E-mail: kohri@post.kek.jp

    2013-08-01

    The early Universe after inflation may have oscillations, kinations (nonoscillatory evolution of a field), topological defects, relativistic and non-relativistic particles at the same time. The Universe whose energy density is a sum of those components can be called the multi-component Universe. The components, which may have distinguishable density scalings, may decay modulated. In this paper we study generation of the curvature perturbations caused by the modulated decay in the multi-component Universe.

  9. Synthetic p-wave interaction and topological superfluids in s-wave quantum gases

    NASA Astrophysics Data System (ADS)

    Pu, Han; Wang, Bin; Zheng, Zhen; Zou, Xubo; Guo, Guangcan

    2016-05-01

    P-wave interaction in cold atoms may give rise to exotic topological superfluids. However, realization of p-wave interaction in cold atom system is experimentally challenging. Here we propose a simple scheme to synthesize effective p-wave interaction in conventional s-wave interacting quantum gases. The key idea is to load atoms into spin-dependent optical lattice potential. Using two concrete examples involving spin-1/2 fermions, we show how the original system can be mapped into a model describing spinless fermions with nearest neighbor p-wave interaction, whose ground state can be a topological superfluid that supports Majorana fermions under proper conditions. Our proposal has the advantage that it does not require spin-orbit coupling or loading atoms onto higher orbitals, which is the key in earlier proposals to synthesize effective p-wave interaction in s-wave quantum gases, and may provide a completely new route for realizing p-wave topological superfluids.

  10. Quantum cascade laser open-path system for remote sensing of trace gases in Beijing, China

    NASA Astrophysics Data System (ADS)

    Michel, Anna P. M.; Liu, Peter Q.; Yeung, June K.; Corrigan, Paul; Baeck, Mary Lynn; Wang, Zifa; Day, Timothy; Smith, James A.

    2010-11-01

    Exploiting several key characteristics of quantum cascade (QC) lasers, including wide tunability and room-temperature operation, the Quantum Cascade Laser Open-Path System (QCLOPS) was designed for the detection of a range of trace gases and for field deployment in urban environments. Tunability over a wavelength range from 9.3 to 9.8 μm potentially provides the capability for monitoring ozone, ammonia, and carbon dioxide, a suite of trace gases important for air quality and regional climate applications in urban environments. The 2008 Olympic Games in Beijing, China drew attention to air quality problems in urban environments. Prior to and during the Olympic games, regional air quality modifications through factory shutdowns, car restrictions, and construction halts in Beijing and its surrounding areas created a unique test bed for new sensor technologies such as the QCLOPS sensor. We report the design of this novel, open-path air quality sensor and the results of both laboratory tests and field trials during the 2008 Olympic Games in Beijing, China.

  11. Quantum point contacts on two-dimensional electron gases with a strong spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Lee, Joon Sue; Pendaharkar, Mihir; Shojaei, Borzoyeh; McFadden, Anthony P.; Palmstrøm, Chris

    Studies of electrical transport in one-dimensional semiconductors in a presence of a strong spin-orbit interaction are crucial not only for exploring the emergent phenomena, such as topological superconductivity, but also for potential spintronic applications by controlling of the electron spins. We investigate the electrical transport properties of one-dimensional confinement defined by electrostatic potentials on large area two-dimensional electron gases of InAs and InSb, which have a strong spin-orbit coupling. The high-quality InAs and InSb quantum wells are grown on antimonide buffers by molecular beam epitaxy, and the gate-tunable regions are created using Al2O3 or HfO2 gate dielectrics by atomic layer deposition. We will discuss the modulation of spin-orbit coupling in the two-dimensional electron gases and the spin-orbit-induced spin splitting by the split-gate quantum point contacts. This work was supported by Microsoft Research.

  12. Mesoscopic effects in quantum phases of ultracold quantum gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Carr, Lincoln D.; Wall, M. L.; Schirmer, D. G.; Brown, R. C.; Williams, J. E.; Clark, Charles W.

    2010-03-01

    We present a wide array of quantum measures on numerical solutions of one-dimensional Bose- and Fermi-Hubbard Hamiltonians for finite-size systems with open boundary conditions. Specifically, for the Bose-Hubbard Hamiltonian we calculate number, quantum depletion, local von Neumann entropy, generalized entanglement or Q measure, fidelity, and fidelity susceptibility; for the Fermi-Hubbard Hamiltonian we also calculate the pairing correlations, magnetization, charge-density correlations, and antiferromagnetic structure factor. Our numerical method is imaginary time propagation via time-evolving block decimation. As part of our study we provide a careful comparison of canonical versus grand canonical ensembles and Gutzwiller versus entangled simulations. The most striking effect of finite size occurs for bosons: we observe a strong blurring of the tips of the Mott lobes accompanied by higher depletion, and show how the location of the first Mott lobe tip approaches the thermodynamic value as a function of system size.

  13. Quantum optics with quantum gases: Controlled state reduction by designed light scattering

    SciTech Connect

    Mekhov, Igor B.; Ritsch, Helmut

    2009-07-15

    Cavity-enhanced light scattering from an ultracold gas in an optical lattice constitutes a quantum measurement with a controllable form of the measurement backaction. Time-resolved counting of scattered photons alters the state of the atoms without particle loss implementing a quantum nondemolition measurement. The conditional dynamics is given by the interplay between photodetection events (quantum jumps) and no-count processes. The class of emerging atomic many-body states can be chosen via the optical geometry and light frequencies. Light detection along the angle of a diffraction maximum (Bragg angle) creates an atom-number-squeezed state, while light detection at diffraction minima leads to the macroscopic superposition states (Schroedinger cat states) of different atom numbers in the cavity mode. A measurement of the cavity transmission intensity can lead to atom-number-squeezed or macroscopic superposition states depending on its outcome. We analyze the robustness of the superposition with respect to missed counts and find that a transmission measurement yields more robust and controllable superposition states than the ones obtained by scattering at a diffraction minimum.

  14. Mid-infrared spectroscopy for gases and liquids based on quantum cascade technologies.

    PubMed

    Jouy, Pierre; Mangold, Markus; Tuzson, Béla; Emmenegger, Lukas; Chang, Yu-Chi; Hvozdara, Lubos; Herzig, Hans Peter; Wägli, Philip; Homsy, Alexandra; de Rooij, Nico F; Wirthmueller, Alexander; Hofstetter, Daniel; Looser, Herbert; Faist, Jérôme

    2014-05-01

    In this paper we present two compact, quantum cascade laser absorption spectroscopy based, sensors developed for trace substance detection in gases and liquids. The gas sensor, in its most integrated version, represents the first system combining a quantum cascade laser and a quantum cascade detector. Furthermore, it uses a toroidal mirror cell with a volume of only 40 cm(3) for a path length of up to 4 m. The analytical performance is assessed by the measurements of isotope ratios of CO2 at ambient abundance. For the (13)CO2/(12)CO2 isotope ratio, a measurement precision of 0.2‰ is demonstrated after an integration time of 600 s. For the liquid sensor, a microfluidic system is used to extract cocaine from saliva into a solvent (PCE) transparent in the mid-infrared. This system is bonded on top of a Si/Ge waveguide and the concentration of cocaine in PCE is measured through the interaction of the evanescent part of the waveguide optical mode and the solvent flowing on top. A detection limit of <100 μg mL(-1) was achieved with this system and down to 10 μg mL(-1) with a simplified, but improved system. PMID:24151636

  15. MPH: A Library for Distributed Multi-Component Environment

    Energy Science and Technology Software Center (ESTSC)

    2001-05-01

    A growing trend in developing large and complex applications on today's Teraflops compyters is to integrate stand-alone and/or semi-independent program components into a comprehensive simulation package. We develop MPH, a multi-component handshaking library that allows component models recognize and talk to each other in a convenient and consisten way, thus to run multi-component ulti-executable applications effectively on distributed memory architectures. MPH provides the following capabilities: component name registration, resource allocation, inter-component communication, inquiry on themore » multi-component environment, standard in/out redirect. It supports the following four integration mechanisms: Multi-Component Single-Executable (MCSE); Single-Component Multi-Executable (SCME); Multi-Component Multi-Executable (MCME); Multi-instance Multi-Executable (MIME). MPH currently works on IBM SP, SGI Origin, Compaq AlphaSC, Cray T3E, and PC clusters. It is being adopted in NCAR's CCSM and Colorado State University's icosahedra grid coupled model. A joint communicator between any two components could be created. MPI communication between local processors and remote processors are invoked through component names and the local id. More functions are available to inquire the global-id, local-id, number of executales, etc.« less

  16. Amine-phenyl multi-component gradient stationary phases.

    PubMed

    Dewoolkar, Veeren C; Kannan, Balamurali; Ashraf, Kayesh M; Higgins, Daniel A; Collinson, Maryanne M

    2015-09-01

    Continuous multi-component gradients in amine and phenyl groups were fabricated using controlled rate infusion (CRI). Solutions prepared from either 3-aminopropyltriethoxysilane (APTEOS) or phenyltrimethoxysilane (PTMOS) were infused, in a sequential fashion, at a controlled rate into an empty graduated cylinder housing a vertically aligned thin layer chromatography (TLC) plate. The hydrolyzed precursors reacted with an abundance of silanol (SiOH) groups on the TLC plates, covalently attaching the functionalized silane to its surface. The extent of modification by phenyl and amine was determined by the kinetics of each reaction and the exposure time at each point along the TLC plate. The local concentrations of phenyl and amine were measured using diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy, respectively. The profile of the multi-component gradients strongly depended on the order of infusion, the direction of the gradient and the presence of available surface silanol groups. A slightly higher amount of phenyl can be deposited on the TLC plate by first modifying its surface with amine groups as they serve as a catalyst, enhancing condensation. Separation of water- and fat-soluble vitamins and the control of retention factors were demonstrated on the multi-component gradient TLC plates. Uniformly modified and single-component TLC plates gave different separations compared to the multi-component gradient plates. The retention factors of the individual vitamins depended on the order of surface modification, the spotting end, and whether the multi-component gradients align or oppose each other. PMID:26255112

  17. Statistical mechanics of Coulomb gases as quantum theory on Riemann surfaces

    NASA Astrophysics Data System (ADS)

    Gulden, Tobias; Janas, Michael; Kamenev, Alex

    2014-03-01

    Statistical mechanics of 1D Coulomb gases may be mapped onto (in general) non-Hermitian quantum mechanics. We use this example to develop non-Hermitian instanton calculus. Treating momentum and coordinate as independent complex variables, constant energy manifolds are given by Riemann surfaces of genus g >= 1 . The actions along principal cycles on these surfaces obey an ODE in the moduli space of the Riemann surface known as the Picard-Fuchs equation. Solving the Picard-Fuchs equation yields semiclassical spectra as well as instanton effects such as width of Bloch bands (the latter determines energy barrier for charge transport). Both are shown to be in perfect agreement with numerical simulations. Applications include transport through biological ion channels as well as nanofluidics, e.g water filled nanotubes. The work was supported by NSF grant DMR1306734.

  18. Statistical mechanics of Coulomb gases as quantum theory on Riemann surfaces

    SciTech Connect

    Gulden, T.; Janas, M.; Koroteev, P.; Kamenev, A.

    2013-09-15

    Statistical mechanics of a 1D multivalent Coulomb gas can be mapped onto non-Hermitian quantum mechanics. We use this example to develop the instanton calculus on Riemann surfaces. Borrowing from the formalism developed in the context of the Seiberg-Witten duality, we treat momentum and coordinate as complex variables. Constant-energy manifolds are given by Riemann surfaces of genus g {>=} 1. The actions along principal cycles on these surfaces obey the ordinary differential equation in the moduli space of the Riemann surface known as the Picard-Fuchs equation. We derive and solve the Picard-Fuchs equations for Coulomb gases of various charge content. Analysis of monodromies of these solutions around their singular points yields semiclassical spectra as well as instanton effects such as the Bloch bandwidth. Both are shown to be in perfect agreement with numerical simulations.

  19. Engineering quantum magnetism in one-dimensional trapped Fermi gases with p -wave interactions

    NASA Astrophysics Data System (ADS)

    Yang, Lijun; Guan, Xiwen; Cui, Xiaoling

    2016-05-01

    The highly controllable ultracold atoms in a one-dimensional (1D) trap provide a new platform for the ultimate simulation of quantum magnetism. In this regard, the Néel antiferromagnetism and the itinerant ferromagnetism are of central importance and great interest. Here we show that these magnetic orders can be achieved in the strongly interacting spin-1/2 trapped Fermi gases with additional p -wave interactions. In this strong-coupling limit, the 1D trapped Fermi gas exhibits an effective Heisenberg spin X X Z chain in the anisotropic p -wave scattering channels. For a particular p -wave attraction or repulsion within the same species of fermionic atoms, the system displays ferromagnetic domains with full spin segregation or the antiferromagnetic spin configuration in the ground state. Such engineered magnetisms are likely to be probed in a quasi-1D trapped Fermi gas of 40K atoms with very close s -wave and p -wave Feshbach resonances.

  20. Fractional Quantum Hall Effects with Bose-gases in Rotating Optical Lattice Potentials

    NASA Astrophysics Data System (ADS)

    Gemelke, Nathan; Sarajlic, Edina; Chu, Steven

    2008-05-01

    It has previously been noted that an analog to the fractional quantum-Hall (FQH) effect for two-dimensional electron gases can be produced with harmonically trapped and rotating neutral atoms. We report progress investigating FQH-like effects in the centrifugal limit of small, rotating, two-dimensional Bose gases. An ensemble of such systems is prepared in an optical lattice with locally rotating on-site potentials, produced by manipulation only of lattice beam optical phases. The non- rotating few-atom ground states are adiabatically transformed to higher angular momentum by applying a time-dependent sweep of rotation rate and deformation of the local lattice potential. Near the centrifugal limit, where the trap rotates at its vibration frequency, correlation is expected as a result of collisions. The onset of this behavior is probed by a combination of photoassociative transitions to bound molecules, and careful analysis of time-of-flight momentum distributions of atoms suddenly released from the lattice.

  1. Elliptical polarization favors long quantum orbits in high-order above-threshold ionization of noble gases.

    PubMed

    Lai, XuanYang; Wang, ChuanLiang; Chen, YongJu; Hu, ZiLong; Quan, Wei; Liu, XiaoJun; Chen, Jing; Cheng, Ya; Xu, ZhiZhan; Becker, Wilhelm

    2013-01-25

    We demonstrate the significant role of long quantum orbits in strong-field atomic processes by investigating experimentally and theoretically the above-threshold ionization spectra of noble gases in intense elliptically polarized laser pulses. With increasing laser ellipticity, the yields of different energy regions of the measured electron spectrum in high-order above-threshold ionization drop at different rates. The experimental features can be reproduced by a theoretical simulation based on quantum-orbit theory, revealing that increasing ellipticity favors the contributions of the long quantum orbits in the high-order above-threshold ionization process. PMID:25166161

  2. Quantum phases of quadrupolar Fermi gases in coupled one-dimensional systems

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Min; Lahrz, M.; Mathey, L.

    2014-01-01

    Following the recent proposal to create quadrupolar gases [Bhongale et al., Phys. Rev. Lett. 110, 155301 (2013), 10.1103/PhysRevLett.110.155301], we investigate what quantum phases can be created in these systems in one dimension. We consider a geometry of two coupled one-dimensional (1D) systems, and derive the quantum phase diagram of ultracold fermionic atoms interacting via quadrupole-quadrupole interactions within a Tomonaga-Luttinger-liquid framework. We map out the phase diagram as a function of the distance between the two tubes and the angle between the direction of the tubes and the quadrupolar moments. The latter can be controlled by an external field. We show that there are two magic angles θB,1c and θB,2c between 0 and π /2, where the intratube quadrupolar interactions vanish and change signs. Adopting a pseudospin language with regard to the two 1D systems, the system undergoes a spin-gap transition and displays a zigzag density pattern, above θB,2c and below θB,1c. Between the two magic angles, we show that polarized triplet superfluidity and a planar spin-density-wave order compete with each other. The latter corresponds to a bond-order solid in higher dimensions. We demonstrate that this order can be further stabilized by applying a commensurate periodic potential along the tubes.

  3. Numerical methods for atomic quantum gases with applications to Bose-Einstein condensates and to ultracold fermions

    NASA Astrophysics Data System (ADS)

    Minguzzi, A.; Succi, S.; Toschi, F.; Tosi, M. P.; Vignolo, P.

    2004-06-01

    The achievement of Bose-Einstein condensation in ultra-cold vapours of alkali atoms has given enormous impulse to the study of dilute atomic gases in condensed quantum states inside magnetic traps and optical lattices. High-purity and easy optical access make them ideal candidates to investigate fundamental issues on interacting quantum systems. This review presents some theoretical issues which have been addressed in this area and the numerical techniques which have been developed and used to describe them, from mean-field models to classical and quantum simulations for equilibrium and dynamical properties. After an introductory overview on dilute quantum gases, both in the homogeneus state and under harmonic or periodic confinement, the article is organized in three main sections. The first concerns Bose-condensed gases at zero temperature, with main regard to the properties of the ground state in different confinements and to collective excitations and transport in the condensate. Bose-Einstein-condensed gases at finite temperature are addressed in the next section, the main emphasis being on equilibrium properties and phase transitions and on dynamical and transport properties associated with the presence of the thermal cloud. Finally, the last section is focused on theoretical and computational issues that have emerged from the efforts to drive gases of fermionic atoms and boson-fermion mixtures deep into the quantum degeneracy regime, with the aim of realizing novel superfluids from fermion pairing. The attention given in this article to methods beyond standard mean-field approaches should make it a useful reference point for future advances in these areas.

  4. Higher orbital physics and artificial gauge fields with ultracold quantum gases

    NASA Astrophysics Data System (ADS)

    Sengstock, Klaus

    2013-03-01

    Recently the physics of quantum gases in higher orbitals attracted a lot of attention, theoretically and experimentally. We report on studies of a new type of superfluid described by a complex order parameter, resulting from an interaction-induced hybridization of the two lowest orbitals for a binary spin-mixture. As a main result we observe a quantum phase transition between the normal superfluid and this unconventional superfluid phase, where the local phase angle of the complex order parameter is continuously twisted between neighboring lattice sites. In addition we discuss new experimental work on the creation of artificial gauge potentials for neutral atoms in 1D and 2D lattices, which do not rely on the internal structure of the atoms. Via a time-dependent driving of the optical lattice we have full control over amplitude and phase of the complex valued hopping parameters. In a 2D triangular lattice, we demonstrate the realization of gauge invariant staggered fluxes. Our system consists of an array of tubes filled with bosonic atoms having a well-defined local phase. The phase distribution obtained in presence of large amplitude staggered fluxes - where frustration plays a key role - obeys two fundamental symmetries, the discrete Ising symmetry (Z2) and a continuous global phase symmetry (U(1)). Via the full control of the staggered gauge fields, we are able to break the Ising symmetry on purpose which means lifting the degeneracy of the two possible Ising states, in analogy to a longitudinal homogenous magnetic field in the standard Ising-Spin model. The measurements reveal ``textbook like'' magnetization curves with the well known dependence on both, the external magnetic field and the temperature. We observe a thermally driven phase transition from an ordered Ising (ferromagnetic) to an unordered (paramagnetic) state. Future directions to combine orbital physics and gauge fields will be discussed.

  5. Fractional quantum Hall physics with ultracold Rydberg gases in artificial gauge fields

    NASA Astrophysics Data System (ADS)

    Grusdt, F.; Fleischhauer, M.

    2013-04-01

    We study ultracold Rydberg-dressed Bose gases subject to artificial gauge fields in the fractional quantum Hall (FQH) regime. The characteristics of the Rydberg interaction give rise to interesting many-body ground states different from standard FQH physics in the lowest Landau level. The nonlocal but rapidly decreasing interaction potential favors crystalline ground states for very dilute systems. While a simple Wigner crystal becomes energetically favorable compared to the Laughlin liquid for filling fractions ν<1/12, a correlated crystal of composite particles emerges already for ν≤1/6 with a large energy gap to the simple Wigner crystal. The presence of a new length scale, the Rydberg blockade radius aB, gives rise to a bubble crystal phase for ν≲1/4 when the average particle distance becomes less than aB, which describes the region of saturated, almost constant interaction potential. For larger fillings indications for strongly correlated cluster liquids are found.

  6. Electrostatic twisted modes in multi-component dusty plasmas

    NASA Astrophysics Data System (ADS)

    Ayub, M. K.; Ali, S.; Ikram, M.

    2016-01-01

    Various electrostatic twisted modes are re-investigated with finite orbital angular momentum in an unmagnetized collisionless multi-component dusty plasma, consisting of positive/negative charged dust particles, ions, and electrons. For this purpose, hydrodynamical equations are employed to obtain paraxial equations in terms of density perturbations, while assuming the Gaussian and Laguerre-Gaussian (LG) beam solutions. Specifically, approximated solutions for potential problem are studied by using the paraxial approximation and expressed the electric field components in terms of LG functions. The energy fluxes associated with these modes are computed and corresponding expressions for orbital angular momenta are derived. Numerical analyses reveal that radial/angular mode numbers as well as dust number density and dust charging states strongly modify the LG potential profiles attributed to different electrostatic modes. Our results are important for understanding particle transport and energy transfer due to wave excitations in multi-component dusty plasmas.

  7. Multi-component transparent conducting oxides: progress in materials modelling

    NASA Astrophysics Data System (ADS)

    Walsh, Aron; Da Silva, Juarez L. F.; Wei, Su-Huai

    2011-08-01

    Transparent conducting oxides (TCOs) play an essential role in modern optoelectronic devices through their combination of electrical conductivity and optical transparency. We review recent progress in our understanding of multi-component TCOs formed from solid solutions of ZnO, In2O3, Ga2O3 and Al2O3, with a particular emphasis on the contributions of materials modelling, primarily based on density functional theory. In particular, we highlight three major results from our work: (i) the fundamental principles governing the crystal structures of multi-component oxide structures including (In2O3)(ZnO)n and (In2O3)m(Ga2O3)l(ZnO)n; (ii) the relationship between elemental composition and optical and electrical behaviour, including valence band alignments; (iii) the high performance of amorphous oxide semiconductors. On the basis of these advances, the challenge of the rational design of novel electroceramic materials is discussed.

  8. Structure and compositional studies of multi-component nanoparticles

    NASA Astrophysics Data System (ADS)

    Malyavanatham, Gokul

    The laser ablation of microparticle (LAM) process was used to study nanoparticles of multi-component materials. The production process utilized laser ablation of a continuously flowing aerosol of micron-sized particles under a gas ambient. An aerosol generator entrained microparticles into a gas flow and directed them through a nozzle into a laser interaction cell. After plasma breakdown, the shock wave propagated through the microparticles and the nanoparticles condensed behind this shockwave. Two methods were developed to collect nanoparticles; the first method used supersonic impaction on substrates at room temperature to enable direct writing of thick films and the second method used electric fields to deflect and collect charged, individual nanoparticles. Two methods for generating multi-component nanostructured materials were studied. The first method involved feeding single-phase microparticles containing the desired composition. Lead Zirconate Titanate (PZT) microparticles were used to generate nanoparticles that were then impacted onto substrates to produce thick films. Quality, morphology, crystallization and composition variations of these thick films were analyzed using material characterization techniques. Segregation of elements and an overall deficiency in Zr and Ti were observed in the deposited thick films as a result of the agglomerated state of the PZT microparticles. However, the analysis for this material system was complicated by the presence of multiple compounds. To develop a further understanding of how segregation occurs in multi-component systems during the LAM process, a second method for generating multi-component nanoparticles by feeding mixtures of single component microparticles was studied. Nanoparticles generated by ablation of Cu and Au microparticle mixtures were collected electrostatically and analyzed. Interactions between exploding microparticles resulted in condensation of nanoparticles that were non-equilibrium solid

  9. Multi-component generalization of the Camassa-Holm equation

    NASA Astrophysics Data System (ADS)

    Xia, Baoqiang; Qiao, Zhijun

    2016-09-01

    In this paper, we propose a multi-component system of the Camassa-Holm equation, denoted by CH(N , H), with 2 N components and an arbitrary smooth function H. This system is shown to admit Lax pair and infinitely many conservation laws. We particularly study the case N = 2 and derive the bi-Hamiltonian structures and peaked soliton (peakon) solutions for some examples.

  10. Multi-component stress history measurements and analysis

    SciTech Connect

    Stout, R.B.; Larson, D.B.

    1987-08-01

    Piezoresistance foil gages were tested dynamically in multi-component stress-strain experiments in order that the actual shock wave conditions of underground nuclear testing could be more closely simulated. The multi-component stress-strain histories were created in polymethylmethacrylate (PMMA) by using chemical explosions to generate spherical shock waves. In addition to the resistivity measurements from the foil gages, particle velocity was also measured at several radial positions from the explosion to provide a complete set of data for analysis. The gage interpretation (inverse) problem for multi-component stress-strain fields requires obtaining a sufficient number of independent measurements so that the different stress-strain components influencing the gage response can be uniquely inferred. The piezoresistance measurements provided data from a triple material foil gage and from ytterbium foil gages (bare gages). An analysis shows that the triple material gage containing foils of ytterbium, manganin, and constantan provided three independent resistivity measurements for the gage oriented in a perpendicular direction relative to the radial propagating shock front. An analysis of the ytterbium foil gages, which were tested in both perpendicular (normal) and parallel (tangential) directions relative to the radial shock front, show the resistivity responses from these two orientations are independent measurements. The results from the analyses of the gages compared well with experimental data. This analysis shows clearly that the material properties of the foil, the dimensions of the foil, and the material surrounding the foil greatly influence the total resistivity response of foil gages in a multi-component stress-strain field. 25 refs., 16 figs.

  11. Fluid description of multi-component solar partially ionized plasma

    SciTech Connect

    Khomenko, E. Collados, M.; Vitas, N.; Díaz, A.

    2014-09-15

    We derive self-consistent formalism for the description of multi-component partially ionized solar plasma, by means of the coupled equations for the charged and neutral components for an arbitrary number of chemical species, and the radiation field. All approximations and assumptions are carefully considered. Generalized Ohm's law is derived for the single-fluid and two-fluid formalism. Our approach is analytical with some order-of-magnitude support calculations. After general equations are developed, we particularize to some frequently considered cases as for the interaction of matter and radiation.

  12. Multi-component symmetry-projected approach for molecular ground state correlations

    SciTech Connect

    Jiménez-Hoyos, Carlos A.; Rodríguez-Guzmán, R.; Scuseria, Gustavo E.

    2013-11-28

    The symmetry-projected Hartree–Fock ansatz for the electronic structure problem can efficiently account for static correlation in molecules, yet it is often unable to describe dynamic correlation in a balanced manner. Here, we consider a multi-component, systematically improvable approach, that accounts for all ground state correlations. Our approach is based on linear combinations of symmetry-projected configurations built out of a set of non-orthogonal, variationally optimized determinants. The resulting wavefunction preserves the symmetries of the original Hamiltonian even though it is written as a superposition of deformed (broken-symmetry) determinants. We show how short expansions of this kind can provide a very accurate description of the electronic structure of simple chemical systems such as the nitrogen and the water molecules, along the entire dissociation profile. In addition, we apply this multi-component symmetry-projected approach to provide an accurate interconversion profile among the peroxo and bis(μ-oxo) forms of [Cu{sub 2}O{sub 2}]{sup 2+}, comparable to other state-of-the-art quantum chemical methods.

  13. Twisted Landau damping rates in multi-component dusty plasmas

    NASA Astrophysics Data System (ADS)

    Ali, S.; Bukhari, S.; Mendonca, J. T.

    2016-03-01

    Keeping in view the kinetic treatment for plasma particles, the electrostatic twisted dust-acoustic (DA) and dust-ion-acoustic (DIA) waves are investigated in a collisionless unmagnetized multi-component dusty plasma, whose constituents are the electrons, singly ionized positive ions, and negatively charged massive dust particulates. With this background, the Vlasov-Poisson equations are coupled together to derive a generalized dielectric constant by utilizing the Laguerre-Gaussian perturbed distribution function and electrostatic potential in the paraxial limit. The dispersion and damping rates of twisted DA and DIA waves are analyzed with finite orbital angular momentum states in a multi-component dusty plasma. Significant modifications concerning the real wave frequencies and damping rates appeared with varying twisted dimensionless parameter and dust concentration. In particular, it is shown that dust concentration enhances the phase speed of the DIA waves in contrary to DA waves, whereas the impact of twisted parameter reduces the frequencies of both DA and DIA waves. The results should be useful for the understanding of particle transport and trapping phenomena caused by wave excitation in laboratory dusty plasmas.

  14. Effective binary theory of multi-component nucleation

    SciTech Connect

    Kalikmanov, V. I.

    2015-03-28

    Classical theory of multi-component nucleation [O. Hirschfelder, J. Chem. Phys. 61, 2690 (1974)] belongs to the class of the so-called intractable problems: it requires computational time which is an exponential function of the number of components N. For a number of systems of practical interest with N > 10, the brute-force use of the classical theory becomes virtually impossible and one has to resort to an effective medium approach. We present an effective binary model which captures important physics of multi-component nucleation. The distinction between two effective species is based on the observation that while all N components contribute to the cluster thermodynamic properties, there is only a part of them which trigger the nucleation process. The proposed 2D-theory takes into account adsorption by means of the Gibbs dividing surface formalism and uses statistical mechanical considerations for the treatment of small clusters. Theoretical predictions for binary-, ternary-, and 14-component mixtures are compared with available experimental data and other models.

  15. Efficient all-optical production of large Li6 quantum gases using D1 gray-molasses cooling

    NASA Astrophysics Data System (ADS)

    Burchianti, A.; Valtolina, G.; Seman, J. A.; Pace, E.; De Pas, M.; Inguscio, M.; Zaccanti, M.; Roati, G.

    2014-10-01

    We use a gray molasses operating on the D1 atomic transition to produce degenerate quantum gases of Li6 with a large number of atoms. This sub-Doppler cooling phase allows us to lower the initial temperature of 109 atoms from 500 to 40 μK in 2 ms. We observe that D1 cooling remains effective into a high-intensity infrared dipole trap where two-state mixtures are evaporated to reach the degenerate regime. We produce molecular Bose-Einstein condensates of up to 5 × 105 molecules and weakly interacting degenerate Fermi gases of 7×105 atoms at T /TF<0.1 with a typical experimental duty cycle of 11 s.

  16. Transport phenomena in correlated quantum liquids: Ultracold Fermi gases and F/N junctions

    NASA Astrophysics Data System (ADS)

    Li, Hua

    Landau Fermi-liquid theory was first introduced by L. D. Landau in the effort of understanding the normal state of Fermi systems, where the application of the concept of elementary excitations to the Fermi systems has proved very fruitful in clarifying the physics of strongly correlated quantum systems at low temperatures. In this thesis, I use Landau Fermi-liquid theory to study the transport phenomena of two different correlated quantum liquids: the strongly interacting ultracold Fermi gases and the ferromagnet/normal-metal (F/N) junctions. The detailed work is presented in chapter II and chapter III of this thesis, respectively. Chapter I holds the introductory part and the background knowledge of this thesis. In chapter II, I study the transport properties of a Fermi gas with strong attractive interactions close to the unitary limit. In particular, I compute the transport lifetimes of the Fermi gas due to superfluid fluctuations above the BCS transition temperature Tc. To calculate the transport lifetimes I need the scattering amplitudes. The scattering amplitudes are dominated by the superfluid fluctuations at temperatures just above Tc. The normal scattering amplitudes are calculated from the Landau parameters. These Landau parameters are obtained from the local version of the induced interaction model for computing Landau parameters. I also calculate the leading order finite temperature corrections to the various transport lifetimes. A calculation of the spin diffusion coefficient is presented in comparison to the experimental findings. Upon choosing a proper value of F0a, I am able to present a good match between the theoretical result and the experimental measurement, which indicates the presence of the superfluid fluctuations near Tc. Calculations of the viscosity, the viscosity/entropy ratio and the thermal conductivity are also shown in support of the appearance of the superfluid fluctuations. In chapter III, I study the spin transport in the low

  17. Ground state of rotating ultracold quantum gases with anisotropic spin—orbit coupling and concentrically coupled annular potential

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Tan, Ren-Bing; Du, Zhi-Jing; Zhao, Wen-Yu; Zhang, Xiao-Fei; Zhang, Shou-Gang

    2014-07-01

    Motivated by recent experimental realization of synthetic spin—orbit coupling in neutral quantum gases, we consider the quasi-two-dimensional rotating two-component Bose—Einstein condensates with anisotropic Rashba spin—orbit coupling subject to concentrically coupled annular potential. For experimentally feasible parameters, the rotating condensate exhibits a variety of rich ground state structures by varying the strengths of the spin—orbit coupling and rotational frequency. Moreover, the phase transitions between different ground state phases induced by the anisotropic spin—orbit coupling are obviously different from the isotropic one.

  18. Potential energy curves for Mo2: multi-component symmetry-projected Hartree-Fock and beyond

    NASA Astrophysics Data System (ADS)

    Bytautas, Laimutis; Jiménez-Hoyos, Carlos A.; Rodríguez-Guzmán, R.; Scuseria, Gustavo E.

    2014-07-01

    The molybdenum dimer is an example of a transition metal system with a formal sextuple bond that constitutes a challenging case for ab initio quantum chemistry methods. In particular, the complex binding pattern in the Mo2 molecule requires a high-quality description of non-dynamic and dynamic electron correlation in order to yield the correct shape of the potential energy curve. The present study examines the performance of a recently implemented multi-component symmetry projected Hartree-Fock (HF) approach. In this work, the spin and spatial symmetries of a trial wavefunction written in terms of non-orthogonal Slater determinants are deliberately broken and then restored in a variation-after-projection framework. The resulting symmetry-projected HF wavefunctions, which possess well-defined quantum numbers, can account for static and some dynamic correlations. A single symmetry-projected configuration in a D∞hS-UHF or a D∞hKS-UHF framework offers a reasonable description of the potential energy curve of Mo2, though the binding energy is too small for the former. Our multi-component strategy offers a way to improve on the single configuration result in a systematic way towards the exact wavefunction: in the def2-TZVP basis set considered in this study, a 7-determinant multi-component D∞hS-UHF approach yields a bond length of 2.01 Å, in good agreement with experimental results, while the predicted binding energy is 39.2 mhartree. The results of this exploratory study suggest that a multi-component symmetry-projected HF stategy is a promising alternative in a high-accuracy description of the electronic structure of challenging systems. We also present and discuss some benchmark calculations based on the CEEIS-FCI (correlation energy extrapolation by intrinsic scaling - full configuration interaction) method for selected geometries.

  19. Multi-component intermetallic electrodes for lithium batteries

    DOEpatents

    Thackeray, Michael M; Trahey, Lynn; Vaughey, John T

    2015-03-10

    Multi-component intermetallic negative electrodes prepared by electrochemical deposition for non-aqueous lithium cells and batteries are disclosed. More specifically, the invention relates to composite intermetallic electrodes comprising two or more compounds containing metallic or metaloid elements, at least one element of which can react with lithium to form binary, ternary, quaternary or higher order compounds, these compounds being in combination with one or more other metals that are essentially inactive toward lithium and act predominantly, but not necessarily exclusively, to the electronic conductivity of, and as current collection agent for, the electrode. The invention relates more specifically to negative electrode materials that provide an operating potential between 0.05 and 2.0 V vs. metallic lithium.

  20. Closure conditions for non-equilibrium multi-component models

    NASA Astrophysics Data System (ADS)

    Müller, S.; Hantke, M.; Richter, P.

    2016-07-01

    A class of non-equilibrium models for compressible multi-component fluids in multi-dimensions is investigated taking into account viscosity and heat conduction. These models are subject to the choice of interfacial pressures and interfacial velocity as well as relaxation terms for velocity, pressure, temperature and chemical potentials. Sufficient conditions are derived for these quantities that ensure meaningful physical properties such as a non-negative entropy production, thermodynamical stability, Galilean invariance and mathematical properties such as hyperbolicity, subcharacteristic property and existence of an entropy-entropy flux pair. For the relaxation of chemical potentials, a two-component and a three-component models for vapor-water and gas-water-vapor, respectively, are considered.

  1. A high resolution upwind scheme for multi-component flows

    NASA Astrophysics Data System (ADS)

    Igra, D.; Takayama, K.

    2002-04-01

    Conservative schemes usually produce non-physical oscillations in multi-component flow solutions. Many methods were proposed to avoid these oscillations. Some of these correction schemes could fix these oscillations in the pressure profile at discontinuities, but the density profile still remained diffused between the two components. In the case of gas-liquid interfaces, density diffusion is not acceptable. In this paper, the interfacial correction scheme proposed by Cocchi et al. was modified to be used in conjunction with the level-set approach. After each time step two grid points that bound the interface are recalculated by using an exact Riemann solver so that pressure oscillations and the density diffusion at discontinuities were eliminated. The scheme presented here can be applied to any type of conservation law solver. Some examples solved by this scheme and their results are compared with the exact solution when available. Good agreement is obtained between the present results and the exact solutions. Copyright

  2. Multi-component joint analysis of surface waves

    NASA Astrophysics Data System (ADS)

    Dal Moro, Giancarlo; Moura, Rui Miguel Marques; Moustafa, Sayed S. R.

    2015-08-01

    Propagation of surface waves can occur with complex energy distribution amongst the various modes. It is shown that even simple VS (shear-wave velocity) profiles can generate velocity spectra that, because of a complex mode excitation, can be quite difficult to interpret in terms of modal dispersion curves. In some cases, Rayleigh waves show relevant differences depending on the considered component (radial or vertical) and the kind of source (vertical impact or explosive). Contrary to several simplistic assumptions often proposed, it is shown, both via synthetic and field datasets, that the fundamental mode of Rayleigh waves can be almost completely absent. This sort of evidence demonstrates the importance of a multi-component analysis capable of providing the necessary elements to properly interpret the data and adequately constrain the subsurface model. It is purposely shown, also through the sole use of horizontal geophones, how it can be possible to efficiently and quickly acquire both Love and Rayleigh (radial-component) waves. The presented field dataset reports a case where Rayleigh waves (both their vertical and radial components) appear largely dominated by higher modes with little or no evidence of the fundamental mode. The joint inversion of the radial and vertical components of Rayleigh waves jointly with Love waves is performed by adopting a multi-objective inversion scheme based on the computation of synthetic seismograms for the three considered components and the minimization of the whole velocity spectra misfits (Full Velocity Spectra - FVS - inversion). Such a FVS multi-component joint inversion can better handle complex velocity spectra thus providing a more robust subsurface model not affected by erroneous velocity spectra interpretations and non-uniqueness of the solution.

  3. Quantum measurement-induced antiferromagnetic order and density modulations in ultracold Fermi gases in optical lattices.

    PubMed

    Mazzucchi, Gabriel; Caballero-Benitez, Santiago F; Mekhov, Igor B

    2016-01-01

    Ultracold atomic systems offer a unique tool for understanding behavior of matter in the quantum degenerate regime, promising studies of a vast range of phenomena covering many disciplines from condensed matter to quantum information and particle physics. Coupling these systems to quantized light fields opens further possibilities of observing delicate effects typical of quantum optics in the context of strongly correlated systems. Measurement backaction is one of the most funda- mental manifestations of quantum mechanics and it is at the core of many famous quantum optics experiments. Here we show that quantum backaction of weak measurement can be used for tailoring long-range correlations of ultracold fermions, realizing quantum states with spatial modulations of the density and magnetization, thus overcoming usual requirement for a strong interatomic interactions. We propose detection schemes for implementing antiferromagnetic states and density waves. We demonstrate that such long-range correlations cannot be realized with local addressing, and they are a consequence of the competition between global but spatially structured backaction of weak quantum measurement and unitary dynamics of fermions. PMID:27510369

  4. Quantum measurement-induced antiferromagnetic order and density modulations in ultracold Fermi gases in optical lattices

    PubMed Central

    Mazzucchi, Gabriel; Caballero-Benitez, Santiago F.; Mekhov, Igor B.

    2016-01-01

    Ultracold atomic systems offer a unique tool for understanding behavior of matter in the quantum degenerate regime, promising studies of a vast range of phenomena covering many disciplines from condensed matter to quantum information and particle physics. Coupling these systems to quantized light fields opens further possibilities of observing delicate effects typical of quantum optics in the context of strongly correlated systems. Measurement backaction is one of the most funda- mental manifestations of quantum mechanics and it is at the core of many famous quantum optics experiments. Here we show that quantum backaction of weak measurement can be used for tailoring long-range correlations of ultracold fermions, realizing quantum states with spatial modulations of the density and magnetization, thus overcoming usual requirement for a strong interatomic interactions. We propose detection schemes for implementing antiferromagnetic states and density waves. We demonstrate that such long-range correlations cannot be realized with local addressing, and they are a consequence of the competition between global but spatially structured backaction of weak quantum measurement and unitary dynamics of fermions. PMID:27510369

  5. Much Polyphony but Little Harmony: Otto Sackur's Groping for a Quantum Theory of Gases

    NASA Astrophysics Data System (ADS)

    Badino, Massimiliano; Friedrich, Bretislav

    2013-09-01

    The endeavor of Otto Sackur (1880-1914) was driven, on the one hand, by his interest in Nernst's heat theorem, statistical mechanics, and the problem of chemical equilibrium and, on the other hand, by his goal to shed light on classical mechanics from the quantum vantage point. Inspired by the interplay between classical physics and quantum theory, Sackur chanced to expound his personal take on the role of the quantum in the changing landscape of physics in the turbulent 1910s. We tell the story of this enthusiastic practitioner of the old quantum theory and early contributor to quantum statistical mechanics, whose scientific ontogenesis provides a telling clue about the phylogeny of his contemporaries.

  6. Probing Spatial Spin Correlations of Ultracold Gases by Quantum Noise Spectroscopy

    SciTech Connect

    Bruun, G. M.; Andersen, Brian M.; Demler, Eugene; Soerensen, Anders S.

    2009-01-23

    Spin noise spectroscopy with a single laser beam is demonstrated theoretically to provide a direct probe of the spatial correlations of cold fermionic gases. We show how the generic many-body phenomena of antibunching, pairing, antiferromagnetic, and algebraic spin liquid correlations can be revealed by measuring the spin noise as a function of laser width, temperature, and frequency.

  7. Multi-phase multi-component reactive flow in Geodynamics

    NASA Astrophysics Data System (ADS)

    Oliveira, Beñat; Afonso, Juan Carlos; Zlotnik, Sergio

    2016-04-01

    Multi-phase multi-component reactive flow (MPMCRF) controls a number of important complex geodynamic/geochemical problems, such as melt generation and percolation, metasomatism, rheological weakening, magmatic differentiation, ore emplacement, and fractionation of chemical elements, to name a few. These interacting processes occur over very different spatial and temporal scales and under very different physico-chemical conditions. Therefore, there is a strong motivation in geodynamics for investigating the equations governing MPMCRF, their mathematical structure and properties, and the numerical techniques necessary to obtain reliable and accurate results. In this contribution we present results from a novel numerical framework to solve multiscale MPMCRF problems in geodynamic contexts. Our approach is based on the effective tracking of the most basic building blocks: internal energy and chemical composition. This is achieved through the combination of rigorous solutions to the conservation equations (mass, energy and momentum) for each dynamic phase (instead of the more common "mixture-type" approach) and the transport equation for the chemical species, within the context of classical irreversible thermodynamics. Interfacial processes such as phase changes, chemical diffusion+reaction, and surface tension effects are explicitly incorporated in the context of ensemble averaging. Phase assemblages, mineral and melt compositions, and all other physical parameters of multi-phase systems are obtained through dynamic free-energy minimization procedures.

  8. Multi-Component Diffusion with Application To Computational Aerothermodynamics

    NASA Technical Reports Server (NTRS)

    Sutton, Kenneth; Gnoffo, Peter A.

    1998-01-01

    The accuracy and complexity of solving multicomponent gaseous diffusion using the detailed multicomponent equations, the Stefan-Maxwell equations, and two commonly used approximate equations have been examined in a two part study. Part I examined the equations in a basic study with specified inputs in which the results are applicable for many applications. Part II addressed the application of the equations in the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) computational code for high-speed entries in Earth's atmosphere. The results showed that the presented iterative scheme for solving the Stefan-Maxwell equations is an accurate and effective method as compared with solutions of the detailed equations. In general, good accuracy with the approximate equations cannot be guaranteed for a species or all species in a multi-component mixture. 'Corrected' forms of the approximate equations that ensured the diffusion mass fluxes sum to zero, as required, were more accurate than the uncorrected forms. Good accuracy, as compared with the Stefan- Maxwell results, were obtained with the 'corrected' approximate equations in defining the heating rates for the three Earth entries considered in Part II.

  9. Multi-component solid solution alloys having high mixing entropy

    SciTech Connect

    Bei, Hongbin

    2015-10-06

    A multi-component high-entropy alloy includes a composition selected from the following group: VNbTaTiMoWRe, VNbTaTiMoW, VNbTaTiMoRe, VNbTaTiWRe, VNbTaMoWRe, VNbTiMoWRe, VTaTiMoWRe, NbTaTiMoWRe, VNbTaTiMo, VNbTaTiW, VNbTaMoW, VNbTiMoW, VTaTiMoW, NbTaTiMoW, VNbTaTiRe, VNbTaMoRe, VNbTiMoRe, VTaTiMoRe, NbTaTiMoRe, VNbTaWRe, VNbTiWRe, VTaTiWRe, NbTaTiWRe, VNbMoWRe, VTaMoWRe, NbTaMoWRe, VTiMoWRe, NbTiMoWRe, TaTiMoWRe, wherein relative amounts of each element vary by no more than .+-.15 atomic %.

  10. Percolation model for selective dissolution of multi-component glasses

    SciTech Connect

    Kale, R.P.; Brinker, C.J.

    1995-03-01

    A percolation model is developed which accounts for most known features of the process of porous glass membrane preparation by selective dissolution of multi-component glasses. The model is founded within tile framework of the classical percolation theory, wherein the components of a glass are represented by random sites on a suitable lattice. Computer simulation is used to mirror the generation of a porous structure during the dissolution process, reproducing many of the features associated with the phenomenon. Simulation results evaluate the effect of the initial composition of the glass on the kinetics of the leaching process as well as the morphology of the generated porous structure. The percolation model establishes the porous structure as a percolating cluster of unreachable constituents in the glass. The simulation algorithm incorporates removal of both, the accessible leachable components in the glass as well as the independent clusters of unreachable components not attached to the percolating cluster. The dissolution process thus becomes limited by the conventional site percolation thresholds of the unreachable components (which restricts the formation of the porous network), as well as the leachable components (which restricts the accessibility of the solvating medium into the glass). The simulation results delineate the range of compositional variations for successful porous glass preparation and predict the variation of porosity, surface area, dissolution rates and effluent composition with initial composition and time. Results compared well with experimental studies and improved upon similar models attempted in die past.

  11. Hybrid apparatus for Bose-Einstein condensation and cavity quantum electrodynamics: Single atom detection in quantum degenerate gases

    SciTech Connect

    Oettl, Anton; Ritter, Stephan; Koehl, Michael; Esslinger, Tilman

    2006-06-15

    We present and characterize an experimental system in which we achieve the integration of an ultrahigh finesse optical cavity with a Bose-Einstein condensate (BEC). The conceptually novel design of the apparatus for the production of BECs features nested vacuum chambers and an in vacuo magnetic transport configuration. It grants large scale spatial access to the BEC for samples and probes via a modular and exchangeable ''science platform.'' We are able to produce {sup 87}Rb condensates of 5x10{sup 6} atoms and to output couple continuous atom lasers. The cavity is mounted on the science platform on top of a vibration isolation system. The optical cavity works in the strong coupling regime of cavity quantum electrodynamics and serves as a quantum optical detector for single atoms. This system enables us to study atom optics on a single particle level and to further develop the field of quantum atom optics. We describe the technological modules and the operation of the combined BEC cavity apparatus. Its performance is characterized by single atom detection measurements for thermal and quantum degenerate atomic beams. The atom laser provides a fast and controllable supply of atoms coupling with the cavity mode and allows for an efficient study of atom field interactions in the strong coupling regime. Moreover, the high detection efficiency for quantum degenerate atoms distinguishes the cavity as a sensitive and weakly invasive probe for cold atomic clouds.

  12. Creation of quantum-degenerate gases of ytterbium in a compact 2D-/3D-magneto-optical trap setup

    SciTech Connect

    Doerscher, Soeren; Thobe, Alexander; Hundt, Bastian; Kochanke, Andre; Le Targat, Rodolphe; Windpassinger, Patrick; Becker, Christoph; Sengstock, Klaus

    2013-04-15

    We report on the first experimental setup based on a 2D-/3D-magneto-optical trap (MOT) scheme to create both Bose-Einstein condensates and degenerate Fermi gases of several ytterbium isotopes. Our setup does not require a Zeeman slower and offers the flexibility to simultaneously produce ultracold samples of other atomic species. Furthermore, the extraordinary optical access favors future experiments in optical lattices. A 2D-MOT on the strong {sup 1}S{sub 0}{yields}{sup 1}P{sub 1} transition captures ytterbium directly from a dispenser of atoms and loads a 3D-MOT on the narrow {sup 1}S{sub 0}{yields}{sup 3}P{sub 1} intercombination transition. Subsequently, atoms are transferred to a crossed optical dipole trap and cooled evaporatively to quantum degeneracy.

  13. Creation of quantum-degenerate gases of ytterbium in a compact 2D-/3D-magneto-optical trap setup.

    PubMed

    Dörscher, Sören; Thobe, Alexander; Hundt, Bastian; Kochanke, André; Le Targat, Rodolphe; Windpassinger, Patrick; Becker, Christoph; Sengstock, Klaus

    2013-04-01

    We report on the first experimental setup based on a 2D-/3D-magneto-optical trap (MOT) scheme to create both Bose-Einstein condensates and degenerate Fermi gases of several ytterbium isotopes. Our setup does not require a Zeeman slower and offers the flexibility to simultaneously produce ultracold samples of other atomic species. Furthermore, the extraordinary optical access favors future experiments in optical lattices. A 2D-MOT on the strong (1)S0 → (1)P1 transition captures ytterbium directly from a dispenser of atoms and loads a 3D-MOT on the narrow (1)S0 → (3)P1 intercombination transition. Subsequently, atoms are transferred to a crossed optical dipole trap and cooled evaporatively to quantum degeneracy. PMID:23635183

  14. Design for robustness of unique, multi-component engineering systems

    NASA Astrophysics Data System (ADS)

    Shelton, Kenneth A.

    2007-12-01

    The purpose of this research is to advance the science of conceptual designing for robustness in unique, multi-component engineering systems. Robustness is herein defined as the ability of an engineering system to operate within a desired performance range even if the actual configuration has differences from specifications within specified tolerances. These differences are caused by three sources, namely manufacturing errors, system degradation (operational wear and tear), and parts availability. Unique, multi-component engineering systems are defined as systems produced in unique or very small production numbers. They typically have design and manufacturing costs on the order of billions of dollars, and have multiple, competing performance objectives. Design time for these systems must be minimized due to competition, high manpower costs, long manufacturing times, technology obsolescence, and limited available manpower expertise. Most importantly, design mistakes cannot be easily corrected after the systems are operational. For all these reasons, robustness of these systems is absolutely critical. This research examines the space satellite industry in particular. Although inherent robustness assurance is absolutely critical, it is difficult to achieve in practice. The current state of the art for robustness in the industry is to overdesign components and subsystems with redundancy and margin. The shortfall is that it is not known if the added margins were either necessary or sufficient given the risk management preferences of the designer or engineering system customer. To address this shortcoming, new assessment criteria to evaluate robustness in design concepts have been developed. The criteria are comprised of the "Value Distance", addressing manufacturing errors and system degradation, and "Component Distance", addressing parts availability. They are based on an evolutionary computation format that uses a string of alleles to describe the components in the

  15. Transport properties of multi-component fluids and of suspensions

    SciTech Connect

    Oppenheim, I.; McBride, J.

    1990-10-31

    This report summarizes work performed under Grant Number DE-FG03-88ER13911 for the period June 15, 1988 through October 31, 1990. The first year's work dealt with derivations of the fundamental equations describing suspensions of inelastic particles. This work was documented in last year's annual progress report, and has since been published in Physica A. We include the published version as an Appendix to this report. During the past year our work has focused on derivations of the nonlinear hydrodynamic equations for multi-component systems. The remainder of this report summarizes the results of these latter studies. The report is organized as follows. In Section 2, we derive a general set of nonlinear hydrodynamic equations for a two-component, classical fluid system. We then show under what circumstances the exact equations can be approximated by the phenomenological, nonlinear Navier-Stokes equations. In Section 3, we use the general results of Section 2 to obtain explicit, nonlinear equations for the evolution of the hydrodynamic variables of two-component fluid mixtures (total mass density, mass density of one of the two species, momentum density and energy density). In Section 4, we give the linearized, fundamental equations that follow from the results of Section 3. In Section 5, we discuss a particular thermodynamic quantity of interest in the hydrodynamic equations, which follows from the composition dependences of the chemical potentials. The dispersion relations which arise from the linearized hydrodynamic equations are derived in Section 6. Finally, in Section 7, we discuss certain effects of long time tail behavior, and section 8 contains a summary.

  16. Propene concentration sensing for combustion gases using quantum-cascade laser absorption near 11 μm

    NASA Astrophysics Data System (ADS)

    Chrystie, Robin S. M.; Nasir, Ehson F.; Farooq, Aamir

    2015-08-01

    We report on a strategy to measure, in situ, the concentration of propene (C3H6) in combustion gases using laser absorption spectroscopy. Pyrolysis of n-butane was conducted in a shock tube, in which the resultant gases were probed using an extended cavity quantum-cascade laser. A differential absorption approach using online and offline wavelengths near λ = 10.9 μm enabled discrimination of propene, cancelling the effects of spectral interference from the simultaneous presence of intermediate hydrocarbon species during combustion. Such interference-free measurements were facilitated by exploiting the =C-H bending mode characteristic to alkenes (olefins). It was confirmed, for intermediate species present during pyrolysis of n-butane, that their absorption cross sections were the same magnitude for both online and offline wavelengths. Hence, this allowed time profiles of propene concentration to be measured during pyrolysis of n-butane in a shock tube. Time profiles of propene subsequent to a passing shock wave exhibit trends similar to that predicted by the well-established JetSurF 1.0 chemical kinetic mechanism, albeit lower by a factor of two. Such a laser diagnostic is a first step to experimentally determining propene in real time with sufficient time resolution, thus aiding the refinement and development of chemical kinetic models for combustion.

  17. Multi-component testing using HZ-PAN and AgZ-PAN Sorbents for OSPREY Model validation

    SciTech Connect

    Garn, Troy G.; Greenhalgh, Mitchell; Lyon, Kevin L.; Law, Jack D.

    2015-04-01

    In efforts to further develop the capability of the Off-gas SeParation and RecoverY (OSPREY) model, multi-component tests were completed using both HZ-PAN and AgZ-PAN sorbents. The primary purpose of this effort was to obtain multi-component xenon and krypton capacities for comparison to future OSPREY predicted multi-component capacities using previously acquired Langmuir equilibrium parameters determined from single component isotherms. Experimental capacities were determined for each sorbent using two feed gas compositions of 1000 ppmv xenon and 150 ppmv krypton in either a helium or air balance. Test temperatures were consistently held at 220 K and the gas flowrate was 50 sccm. Capacities were calculated from breakthrough curves using TableCurve® 2D software by Jandel Scientific. The HZ-PAN sorbent was tested in the custom designed cryostat while the AgZ-PAN was tested in a newly installed cooling apparatus. Previous modeling validation efforts indicated the OSPREY model can be used to effectively predict single component xenon and krypton capacities for both engineered form sorbents. Results indicated good agreement with the experimental and predicted capacity values for both krypton and xenon on the sorbents. Overall, the model predicted slightly elevated capacities for both gases which can be partially attributed to the estimation of the parameters and the uncertainty associated with the experimental measurements. Currently, OSPREY is configured such that one species adsorbs and one does not (i.e. krypton in helium). Modification of OSPREY code is currently being performed to incorporate multiple adsorbing species and non-ideal interactions of gas phase species with the sorbent and adsorbed phases. Once these modifications are complete, the sorbent capacities determined in the present work will be used to validate OSPREY multicomponent adsorption predictions.

  18. (2+1)-dimensional non-isospectral multi-component AKNS equations and its integrable couplings

    SciTech Connect

    Sun Yepeng

    2010-03-08

    (2+1)-dimensional non-isospectral multi-component AKNS equations are derived from an arbitrary order matrix spectral problem. As a reduction, (2+1)-dimensional non-isospectral multi-component Schroedinger equations are obtained. Moreover, new (2+1)-dimensional non-isospectral integrable couplings of the resulting AKNS equations are constructed by enlarging the associated matrix spectral problem.

  19. Alcohol-Related Information in Multi-Component Interventions and College Students' Drinking Behavior

    ERIC Educational Resources Information Center

    Thadani, Vandana; Huchting, Karen; LaBrie, Joseph

    2009-01-01

    Education-only interventions produce little change in drinking behaviors; but, multi-component prevention programs, which include alcohol information as one feature, can decrease drinking. This study examined the role of alcohol knowledge in a multi-component intervention previously found to reduce first-year female college students' alcohol…

  20. Emergent Devil's Staircase without Particle-Hole Symmetry in Rydberg Quantum Gases with Competing Attractive and Repulsive Interactions.

    PubMed

    Lan, Zhihao; Minář, Jiří; Levi, Emanuele; Li, Weibin; Lesanovsky, Igor

    2015-11-13

    The devil's staircase is a fractal structure that characterizes the ground state of one-dimensional classical lattice gases with long-range repulsive convex interactions. Its plateaus mark regions of stability for specific filling fractions which are controlled by a chemical potential. Typically, such a staircase has an explicit particle-hole symmetry; i.e., the staircase at more than half filling can be trivially extracted from the one at less than half filling by exchanging the roles of holes and particles. Here, we introduce a quantum spin chain with competing short-range attractive and long-range repulsive interactions, i.e., a nonconvex potential. In the classical limit the ground state features generalized Wigner crystals that--depending on the filling fraction--are composed of either dimer particles or dimer holes, which results in an emergent complete devil's staircase without explicit particle-hole symmetry of the underlying microscopic model. In our system the particle-hole symmetry is lifted due to the fact that the staircase is controlled through a two-body interaction rather than a one-body chemical potential. The introduction of quantum fluctuations through a transverse field melts the staircase and ultimately makes the system enter a paramagnetic phase. For intermediate transverse field strengths, however, we identify a region where the density-density correlations suggest the emergence of quasi-long-range order. We discuss how this physics can be explored with Rydberg-dressed atoms held in a lattice. PMID:26613435

  1. Emergent Devil's Staircase without Particle-Hole Symmetry in Rydberg Quantum Gases with Competing Attractive and Repulsive Interactions

    NASA Astrophysics Data System (ADS)

    Lan, Zhihao; Minář, Jiří; Levi, Emanuele; Li, Weibin; Lesanovsky, Igor

    2015-11-01

    The devil's staircase is a fractal structure that characterizes the ground state of one-dimensional classical lattice gases with long-range repulsive convex interactions. Its plateaus mark regions of stability for specific filling fractions which are controlled by a chemical potential. Typically, such a staircase has an explicit particle-hole symmetry; i.e., the staircase at more than half filling can be trivially extracted from the one at less than half filling by exchanging the roles of holes and particles. Here, we introduce a quantum spin chain with competing short-range attractive and long-range repulsive interactions, i.e., a nonconvex potential. In the classical limit the ground state features generalized Wigner crystals that—depending on the filling fraction—are composed of either dimer particles or dimer holes, which results in an emergent complete devil's staircase without explicit particle-hole symmetry of the underlying microscopic model. In our system the particle-hole symmetry is lifted due to the fact that the staircase is controlled through a two-body interaction rather than a one-body chemical potential. The introduction of quantum fluctuations through a transverse field melts the staircase and ultimately makes the system enter a paramagnetic phase. For intermediate transverse field strengths, however, we identify a region where the density-density correlations suggest the emergence of quasi-long-range order. We discuss how this physics can be explored with Rydberg-dressed atoms held in a lattice.

  2. Quantum phase transitions in disordered superconductors and detection of modulated superfluidity in imbalanced Fermi gases

    NASA Astrophysics Data System (ADS)

    Swanson, Mason

    Ultracold atomic gas experiments have emerged as a new testing ground for finding elusive, exotic states of matter. One such state that has eluded detection is the Larkin-Ovchinnikov (LO) phase predicted to exist in a system with unequal populations of up and down fermions. This phase is characterized by periodic domain walls across which the order parameter changes sign and the excess polarization is localized Despite fifty years of theoretical and experimental work, there has so far been no unambiguous observation of an LO phase. In this thesis, we propose an experiment in which two fermion clouds, prepared with unequal population imbalances, are allowed to expand and interfere. We show that a pattern of staggered fringes in the interference is unequivocal evidence of LO physics. Finally, we study the superconductor-insulator quantum phase transition. Both superconductivity and localization stand on the shoulders of giants -- the BCS theory of superconductivity and the Anderson theory of localization. Yet, when their combined effects are considered, both paradigms break down, even for s-wave superconductors. In this work, we calculate the dynamical quantities that help guide present and future experiments. Specifically, we calculate the conductivity sigma(o) and the bosonic (pair) spectral function P(o) from quantum Monte Carlo simulations across clean and disorder-driven superconductor-insulator transitions (SIT). Using these quantities, we identify characteristic energy scales in both the superconducting and insulating phases that vanish at the transition due to enhanced quantum fluctuations, despite the persistence of a robust fermionic gap across the SIT. The clean and disordered transition are compared throughout, and we find that disorder leads to enhanced absorption in sigma(o) at low frequencies and a change in the universality class, although the underlying T = 0quantum critical point remains in both transitions.

  3. Quantum phases of atomic Fermi gases with anisotropic spin-orbit coupling

    SciTech Connect

    Iskin, M.; Subasi, A. L.

    2011-10-15

    We consider a general anisotropic spin-orbit coupling and analyze the phase diagrams of both balanced and imbalanced Fermi gases for the entire BCS-BEC evolution. In the first part, we use the self-consistent mean-field theory at zero temperature, and show that the topological structure of the ground-state phase diagrams is quite robust against the effects of anisotropy. In the second part, we go beyond the mean-field description, and investigate the effects of Gaussian fluctuations near the critical temperature. This allows us to derive the time-dependent Ginzburg-Landau theory, from which we extract the effective mass of the Cooper pairs and their critical condensation temperature in the molecular BEC limit.

  4. Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment

    NASA Astrophysics Data System (ADS)

    D'Incao, Jose P.; Willians, Jason R.

    2015-05-01

    Precision atom interferometers (AI) in space are a key element for several applications of interest to NASA. Our proposal for participating in the Cold Atom Laboratory (CAL) onboard the International Space Station is dedicated to mitigating the leading-order systematics expected to corrupt future high-precision AI-based measurements of fundamental physics in microgravity. One important focus of our proposal is to enhance initial state preparation for dual-species AIs. Our proposed filtering scheme uses Feshbach molecular states to create highly correlated mixtures of heteronuclear atomic gases in both their position and momentum distributions. We will detail our filtering scheme along with the main factors that determine its efficiency. We also show that the atomic and molecular heating and loss rates can be mitigated at the unique temperature and density regimes accessible on CAL. This research is supported by the National Aeronautics and Space Administration.

  5. Design for robustness of unique, multi-component engineering systems

    NASA Astrophysics Data System (ADS)

    Shelton, Kenneth A.

    2007-12-01

    The purpose of this research is to advance the science of conceptual designing for robustness in unique, multi-component engineering systems. Robustness is herein defined as the ability of an engineering system to operate within a desired performance range even if the actual configuration has differences from specifications within specified tolerances. These differences are caused by three sources, namely manufacturing errors, system degradation (operational wear and tear), and parts availability. Unique, multi-component engineering systems are defined as systems produced in unique or very small production numbers. They typically have design and manufacturing costs on the order of billions of dollars, and have multiple, competing performance objectives. Design time for these systems must be minimized due to competition, high manpower costs, long manufacturing times, technology obsolescence, and limited available manpower expertise. Most importantly, design mistakes cannot be easily corrected after the systems are operational. For all these reasons, robustness of these systems is absolutely critical. This research examines the space satellite industry in particular. Although inherent robustness assurance is absolutely critical, it is difficult to achieve in practice. The current state of the art for robustness in the industry is to overdesign components and subsystems with redundancy and margin. The shortfall is that it is not known if the added margins were either necessary or sufficient given the risk management preferences of the designer or engineering system customer. To address this shortcoming, new assessment criteria to evaluate robustness in design concepts have been developed. The criteria are comprised of the "Value Distance", addressing manufacturing errors and system degradation, and "Component Distance", addressing parts availability. They are based on an evolutionary computation format that uses a string of alleles to describe the components in the

  6. Memory effects in noninteracting isolated systems from dynamical geometry transformations in ultracold quantum gases

    NASA Astrophysics Data System (ADS)

    Lai, Chen-Yen; Chien, Chin-Chun

    Memory effects have been of broad interest and particularly relevant in condensate matter systems where dynamical properties depend on history. Here we explore possibilities of observing memory effects in simple isolated quantum systems undergoing geometry transformations. By transforming into lattices supporting flat-bands consisting of localized states, memory effects could be observed in ultracold atoms in optical lattices due to different time scales of localized and mobile atoms. As an optical lattice is continuously transformed from a triangular lattice into a kagome or square lattice, the system reach a non-thermal quasi-steady state. In the absence of interactions and dissipations, the emergence of steady states are highly nontrivial and crucial in identifying memory effects unambiguously. Moreover, when the lattices transform from a triangular lattice into a kagome lattice with a flat band, history-dependent density distributions even in noninteracting systems can be observed in fermionic as well as bosonic systems. Rapid growth of cold atom technology and possibilities of various mechanisms for inducing memory effect promise interesting applications of novel quantum devices utilizing memory effect, especially in the thriving field of atomtronics. (arXiv:1510.08978)

  7. Topological semimetal: a probable new state of quantum optical lattice gases protected by D4 symmetry

    NASA Astrophysics Data System (ADS)

    Sun, Kai; Liu, W. Vincent; Das Sarma, S.

    2011-03-01

    We demonstrate that a novel topological semimetal emerges as a parity-protected critical theory for fermionic atoms loaded in the p and d orbital bands of a two-dimensional optical lattice. The new quantum state is characterized by a parabolic band-degeneracy point with Berry flux 2 π , in sharp contrast to the π flux of Dirac points as in graphene. We prove that this topological liquid is a universal property for all lattices of D4 point group symmetry and the band degeneracy is protected by odd parity. Turning on interparticle repulsive interaction, the system undergoes a phase transition to a topological insulator, whose experimental signature includes chiral gapless domain-wall modes, reminiscent of quantum Hall edge states. KS and SDS acknowledge the support of JQI-NSF-PFC, AFOSR-MURI, ARO-DARPA-OLE and ARO-MURI. W.V.L. is supported by ARO and ARO-DARPA-OLE. We thank the KITP at UCSB for its hospitality where this research is supported in part by NSF Grant No. PHY05-51164.

  8. Quantum Monte Carlo study of quasi-one-dimensional Bose gases

    NASA Astrophysics Data System (ADS)

    Astrakharchik, G. E.; Blume, D.; Giorgini, S.; Granger, B. E.

    2004-04-01

    We study the behaviour of quasi-one-dimensional (quasi-1D) Bose gases by Monte Carlo techniques, i.e. by the variational Monte Carlo, the diffusion Monte Carlo and the fixed-node diffusion Monte Carlo techniques. Our calculations confirm and extend our results of an earlier study (Astrakharchik et al 2003 Preprint cond-mat/0308585). We find that a quasi-1D Bose gas (i) is well described by a 1D model Hamiltonian with contact interactions and renormalized coupling constant; (ii) reaches the Tonks-Girardeau regime for a critical value of the 3D scattering length a3D; (iii) enters a unitary regime for |a3D| rarr infin, where the properties of the gas are independent of a3D and are similar to those of a 1D gas of hard-rods and (iv) becomes unstable against cluster formation for a critical value of the 1D gas parameter. The accuracy and implications of our results are discussed in detail.

  9. Multi-component Erlang distribution of plant seed masses and sizes

    NASA Astrophysics Data System (ADS)

    Fan, San-Hong; Wei, Hua-Rong

    2012-12-01

    The mass and the size distributions of plant seeds are very similar to the multi-component Erlang distribution of final-state particle multiplicities in high-energy collisions. We study the mass, length, width, and thickness distributions of pumpkin and marrow squash seeds in this paper. The corresponding distribution curves are obtained and fitted by using the multi-component Erlang distribution. In the comparison, the method of χ2-testing is used. The mass and the size distributions of the mentioned seeds are shown to obey approximately the multi-component Erlang distribution with the component number being 1.

  10. Quantum cascade laser absorption sensor for carbon monoxide in high-pressure gases using wavelength modulation spectroscopy.

    PubMed

    Spearrin, R M; Goldenstein, C S; Jeffries, J B; Hanson, R K

    2014-03-20

    A tunable quantum cascade laser sensor, based on wavelength modulation absorption spectroscopy near 4.8 μm, was developed to measure CO concentration in harsh, high-pressure combustion gases. The sensor employs a normalized second harmonic detection technique (WMS-2f/1f) at a modulation frequency of 50 kHz. Wavelength selection at 2059.91  cm⁻¹ targets the P(20) transition within the fundamental vibrational band of CO, chosen for absorption strength and relative isolation from infrared water and carbon dioxide absorption. The CO spectral model is defined by the Voigt line-shape function, and key line-strength and line-broadening spectroscopic parameters were taken from the literature or measured. Sensitivity analysis identified the CO-N₂ collisional broadening coefficient as most critical for uncertainty mitigation in hydrocarbon/air combustion exhaust measurements, and this parameter was experimentally derived over a range of combustion temperatures (1100-2600 K) produced in a shock tube. Accuracy of the wavelength-modulation-spectroscopy-based sensor, using the refined spectral model, was validated at pressures greater than 40 atm in nonreactive shock-heated gas mixtures. The laser was then free-space coupled to an indium-fluoride single-mode fiber for remote light delivery. The fiber-coupled sensor was demonstrated on an ethylene/air pulse detonation combustor, providing time-resolved (~20  kHz), in situ measurements of CO concentration in a harsh flow field. PMID:24663473

  11. Permutation Symmetry in Spinor Quantum Gases: Selection Rules, Conservation Laws, and Correlations

    NASA Astrophysics Data System (ADS)

    Yurovsky, Vladimir A.

    2014-11-01

    Many-body systems of identical arbitrary-spin particles, with separable spin and spatial degrees of freedom, are considered. Their eigenstates can be classified by Young diagrams, corresponding to nontrivial permutation symmetries (beyond the conventional paradigm of symmetric-antisymmetric states). The present work obtains the following. (a) Selection rules for additional nonseparable (dependent on spins and coordinates) k -body interactions: the Young diagrams, associated with the initial and final states of a transition, can differ by relocation of no more than k boxes between their rows. (b) Correlation rules in which eigenstate-averaged local correlations of k particles vanish if k exceeds the number of columns (for bosons) or rows (for fermions) in the associated Young diagram. It also elucidates the physical meaning of the quantities conserved due to permutation symmetry—in 1929, Dirac identified those with characters of the symmetric group—relating them to experimentally observable correlations of several particles. The results provide a way to control the formation of entangled states belonging to multidimensional non-Abelian representations of the symmetric group. These states can find applications in quantum computation and metrology.

  12. New Design Methods and Algorithms for Multi-component Distillation Processes

    SciTech Connect

    2009-02-01

    This factsheet describes a research project whose main goal is to develop methods and software tools for the identification and analysis of optimal multi-component distillation configurations for reduced energy consumption in industrial processes.

  13. EDITORIAL: Theory of Quantum Gases and Quantum Coherence: The Cortona BEC Workshop, 29 October-2 November 2005

    NASA Astrophysics Data System (ADS)

    Capuzzi, Pablo; Chitra, R.; Menotti, Chiara; Minguzz, Anna; Vignolo, Patrizia

    2006-05-01

    Nonlinear, or multiphoton, interaction of intense laser radiation with matter has been a key research subject for about four decades. Every three years, the International Conference on Multiphoton Processes (ICOMP) covers the latest advances in the field. Intense-field physics has seen phenomenal progress over the last decade. What looked like dreams in the mid-nineties have become routine today. Major theoretical, experimental and technological advances in fundamental science and applications of multiphoton processes cover such diverse areas as precision measurements, femtosecond and now attosecond metrology, quantum control of atomic and molecular dynamics, laser machining of solid state materials, laser acceleration of electrons and protons, and medical applications. This special issue of Journal of Physics B: Atomic, Molecular and Optical Physics (J. Phys. B) contains a collection of articles originating from the Tenth International Conference on Multiphoton Processes (ICOMP 2005) held on 9-14 October 2005 in Orford, Quebec, Canada (general chair Lou DiMauro, Ohio State University, program co-chairs Paul Corkum and Misha Ivanov, National Research Council of Canada). The conference focused on atoms and molecules in strong fields, femtosecond and attosecond processes, propagation of intense pulses, and of course multiphoton processes which lie at the foundation of all these subjects. Articles presented in this issue cover several key areas of intense-field physics. These include strong field ionization of atoms, molecules and inside transparent dielectric materials, methods of generation and characterization of attosecond XUV pulses and pulse trains, and new approaches to using intense laser fields and/or attosecond pulses for studying entangled systems and imaging electronic and nuclear dynamics with sub-Ångstrom spatial and sub-femtosecond temporal resolution. We have tried to group the papers according to these general areas. We would like to use this

  14. Quantum cascade laser based sensor for in situ and real time atmospheric trace gases (CO and N2O) measurements

    NASA Astrophysics Data System (ADS)

    Li, Jingsong; Parchatka, Uwe; Fischer, Horst

    2013-04-01

    In addition to the primary greenhouse gases carbon dioxide (CO2) and methane (CH4), several other atmospheric trace gases are radiatively active, and thereby can also contribute to a greenhouse warming of the lower atmosphere directly or indirectly. Nitrous oxide (N2O) is a greenhouse gas with a global warming potential about 200-300 times that of CO2. Carbon monoxide (CO) is not considered a direct greenhouse gas, mostly because it does not absorb terrestrial thermal IR energy strongly enough. However, CO plays an important role in the oxidative chemistry of Earth's atmosphere, since it is a key trace gas for controlling the budget and distribution of the hydroxyl (OH) radical, which exerts a controlling influence on the gas phase chemistry of many atmospheric species [1]. Therefore, there is a critical need to identify sources and sinks of N2O and CO in order to better understand their impact on global climate change [2]. We present a fast, compact, and precise sensor based-on a novel thermoelectrically (TE) cooled quantum cascade laser (QCL) operating at near-room temperature in CW (continuous-wave) mode for simultaneous detection of atmospheric N2O and CO. The technique is based on atmospheric absorption of these trace species in the mid-infrared region near 4.56 µm, using a single QC laser source and two TE-cooled infrared detectors. Wavelength modulation spectroscopy with second harmonic detection technique in conjunction with a compact multi-pass absorption cell has been employed to demonstrate highly sensitive and precise measurements. CO and N2O at ambient concentration levels are detected simultaneously with a high temporal response (< 1s). Preliminary results (Laboratory investigation and field application) of the sensor's performance will be presented. This completely TE-cooled system shows the capability of long-term, unattended and continuous operation at room temperature without complicated cryogenic cooling [3]. [1] J. A. Logan, M. J. Prather, S. C

  15. Multi-component superstructures self-assembled from nanocrystal building blocks

    NASA Astrophysics Data System (ADS)

    Tan, Rui; Zhu, Hua; Cao, Can; Chen, Ou

    2016-05-01

    More than three decades of intensive study to make high-quality nanocrystals have created a unique toolbox for building multi-component superstructures, which have been recognized as a new generation of metamaterials important to both fundamental sciences and applied technologies. This minireview summarizes recent advances in this exciting field. We will focus our discussion on the synthetic strategies and superstructures of this multi-component metamaterial, and highlight their novel properties and potential applications. Additionally, some perspectives on possible developments in this field are offered at the end of this review. We hope that this minireview will both inform and stimulate research interests for the design and fabrication of these nanocrystal-based multi-component metamaterials for diverse applications in the future.

  16. An Experimental Investigation and Numerical Analysis of Multi-Component Fuel Spray

    NASA Astrophysics Data System (ADS)

    Myong, Kwang-Jae; Arai, Motoyuki; Tanaka, Tomoyuki; Senda, Jiro; Fujimoto, Hajime

    In this study, droplet atomization and vaporization characteristics with multi-component fuel were investigated by experimental and numerical simulation methods. Spray characteristics of multi-component fuel including spray cone angle, spray angle and spray tip penetration were analyzed from shadowgraph imaging. Numerical simulation to investigate spatial distribution of fuel-vapor concentration of each component within multi-component fuel was implemented in KIVA code. Vaporization process was calculated by a simple two-phase region which was approximated by modified saturated liquid-vapor line. Experimental results show that spray cone angle and spray angle become larger increasing in mass fraction of low boiling point component. And spray tip penetration becomes shorter with increasing in mass fraction of low boiling point component in vaporizing spray during that is same on every mixed fuel in non-vaporizing spray. From numerical simulation results, temporal and spatial distribution of each fuel vapor concentration was found to be stratification.

  17. Multi-component superstructures self-assembled from nanocrystal building blocks.

    PubMed

    Tan, Rui; Zhu, Hua; Cao, Can; Chen, Ou

    2016-05-21

    More than three decades of intensive study to make high-quality nanocrystals have created a unique toolbox for building multi-component superstructures, which have been recognized as a new generation of metamaterials important to both fundamental sciences and applied technologies. This minireview summarizes recent advances in this exciting field. We will focus our discussion on the synthetic strategies and superstructures of this multi-component metamaterial, and highlight their novel properties and potential applications. Additionally, some perspectives on possible developments in this field are offered at the end of this review. We hope that this minireview will both inform and stimulate research interests for the design and fabrication of these nanocrystal-based multi-component metamaterials for diverse applications in the future. PMID:27136751

  18. Dual Hierarchies of a Multi-Component Camassa-Holm System

    NASA Astrophysics Data System (ADS)

    Li, Hong-Min; Li, Yu-Qi; Chen, Yong

    2015-10-01

    In this paper, we derive the bi-Hamiltonian structure of a multi-component Camassa-Holm system, which associates with the multi-component AKNS hierarchy and multi-component KN hierarchy via the tri-Hamiltonian duality method. Furthermore, the spectral problems of the dual hierarchies may be obtained. Supported by the National Natural Science Foundation of China under Grant Nos. 11275072 and 11375090, Research Fund for the Doctoral Program of Higher Education of China under No. 20120076110024, the Innovative Research Team Program of the National Natural Science Foundation of China under Grant No. 61321064, Shanghai Knowledge Service Platform for Trustworthy Internet of Things under Grant No. ZF1213, Talent Fund and K.C. Wong Magna Fund in Ningbo University

  19. Lie algebras and Hamiltonian structures of multi-component Ablowitz-Kaup-Newell-Segur hierarchy

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-ying; Zhang, Da-jun

    2013-05-01

    Isospectral and non-isospectral hierarchies of multi-component Ablowitz-Kaup-Newell-Segur (AKNS) are obtained from a matrix spectral problem, then by means of the zero curvature representations of the isospectral flows {Km} and non-isospectral flows {σn}, we construct the symmetries and their algebraic structures for isospectral multi-component AKNS hierarchies, demonstrate the recursive operator L is a strong and hereditary symmetry for the isospectral hierarchy. We also derive that there are implectic operator θ and symplectic operator J such that L = θJ, and discuss the multi-Hamiltonian structures and the Liouville integrability of the isospectral hierarchies.

  20. Porous multi-component material for the capture and separation of species of interest

    DOEpatents

    Addleman, Raymond S.; Chouyyok, Wilaiwan; Li, Xiaohong S.; Cinson, Anthony D.; Gerasimenko, Aleksandr A

    2016-06-21

    A method and porous multi-component material for the capture, separation or chemical reaction of a species of interest is disclosed. The porous multi-component material includes a substrate and a composite thin film. The composite thin film is formed by combining a porous polymer with a nanostructured material. The nanostructured material may include a surface chemistry for the capture of chemicals or particles. The composite thin film is coupled to the support or device surface. The method and material provides a simple, fast, and chemically and physically benign way to integrate nanostructured materials into devices while preserving their chemical activity.

  1. Multi-components determination by single reference standard and HPLC fingerprint analysis for Lamiophlomis rotata Pill.

    PubMed

    Chen, Jing; Wang, Yang; Sun, Guoxiang; Ma, Yongfu; Guo, Xingjie

    2016-07-01

    A validated HPLC method was developed to evaluate the quality of Lamiophlomis rotata Pill combining the multi-components analysis by single reference standard with HPLC fingerprint analysis. Five bioactive components (shanzhiside methyl ester, loganin, 8-O-acetylshanzhiside methyl ester, forsythoside B and luteolin-7-O-β-D-glucopyranoside) were selected as markers to control the quality of L. rotata Pill. The results revealed that the chromatographic fingerprint method coupled with multi-components analysis provides an effective and feasible way to determine the components in L. rotata Pill. PMID:26595778

  2. Development of high quality, density-tunable two-dimensional electron gases for the study of the quantum Hall effect in the 2nd Landau level

    NASA Astrophysics Data System (ADS)

    Watson, John; Mondal, Sumit; Manfra, Michael

    2014-03-01

    We report on progress in state-of-the-art high mobility two-dimensional electron gases (2DEGs) in 30 nm GaAs/AlGaAs quantum wells in which the density is modulated by an in-situ grown back-gate. Such in-situ gates can be grown close to the 2DEG (~ 1 μm) and without doping layers between the 2DEG and gate, resulting in non-hysteretic gating with a very uniform electric field and large gate capacitance. We discuss heterostructure design parameters and device processing conditions leading to low gate leakage currents, low ohmic contact resistances, high electron mobilities (17 x 106 cm2/Vs), and large fractional quantum Hall energy gaps in the second Landau level. Work supported by US DOE Office of Basic Energy Sciences, Division of Materials Sciences and Engineering Award DE-SC0006671.

  3. The Effects of a Multi-Component Intervention on Preschool Children's Literacy Skills

    ERIC Educational Resources Information Center

    Dennis, Lindsay R.

    2016-01-01

    This study examined the effects of a multi-component intervention program (i.e., extended instruction and iPad app technology) on preschool children's vocabulary. Instruction utilizing the intervention program was provided across 6 storybooks, 4 verbs per book, for a total of 24 verbs. Dependent variables included expressive vocabulary,…

  4. [Study on high accuracy detection of multi-component gas in oil-immerse power transformer].

    PubMed

    Fan, Jie; Chen, Xiao; Huang, Qi-Feng; Zhou, Yu; Chen, Gang

    2013-12-01

    In order to solve the problem of low accuracy and mutual interference in multi-component gas detection, a kind of multi-component gas detection network with high accuracy was designed. A semiconductor laser with narrow bandwidth was utilized as light source and a novel long-path gas cell was also used in this system. By taking the single sine signal to modulate the spectrum of laser and using space division multiplexing (SDM) and time division multiplexing (TDM) technique, the detection of multi-component gas was achieved. The experiments indicate that the linearity relevance coefficient is 0. 99 and the measurement relative error is less than 4%. The system dynamic response time is less than 15 s, by filling a volume of multi-component gas into the gas cell gradually. The system has advantages of high accuracy and quick response, which can be used in the fault gas on-line monitoring for power transformers in real time. PMID:24611396

  5. A Multi-Component Model for Assessing Learning Objects: The Learning Object Evaluation Metric (LOEM)

    ERIC Educational Resources Information Center

    Kay, Robin H.; Knaack, Liesel

    2008-01-01

    While discussion of the criteria needed to assess learning objects has been extensive, a formal, systematic model for evaluation has yet to be thoroughly tested. The purpose of the following study was to develop and assess a multi-component model for evaluating learning objects. The Learning Object Evaluation Metric (LOEM) was developed from a…

  6. A Multi-Component Intervention Designed To Reduce Disruptive Classroom Behavior.

    ERIC Educational Resources Information Center

    Kehle, Thomas J.; Bray, Melissa A.; Theodore, Lea A.; Jenson, William R.; Clark, Elaine

    2000-01-01

    Describes research that focused on the design of an effective, economical, and easily implemented treatment for disruptive classroom behavior in both general and special education students. Multi-component treatment options included mystery motivators, token economy with response cost, and antecedent strategies delivered within a group contingency…

  7. 40 CFR 59.506 - How do I demonstrate compliance if I manufacture multi-component kits?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false How do I demonstrate compliance if I manufacture multi-component kits? 59.506 Section 59.506 Protection of Environment ENVIRONMENTAL PROTECTION... § 59.506 How do I demonstrate compliance if I manufacture multi-component kits? (a) If you...

  8. 40 CFR 59.506 - How do I demonstrate compliance if I manufacture multi-component kits?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false How do I demonstrate compliance if I manufacture multi-component kits? 59.506 Section 59.506 Protection of Environment ENVIRONMENTAL PROTECTION... § 59.506 How do I demonstrate compliance if I manufacture multi-component kits? (a) If you...

  9. 40 CFR 59.506 - How do I demonstrate compliance if I manufacture multi-component kits?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false How do I demonstrate compliance if I manufacture multi-component kits? 59.506 Section 59.506 Protection of Environment ENVIRONMENTAL PROTECTION... § 59.506 How do I demonstrate compliance if I manufacture multi-component kits? (a) If you...

  10. 40 CFR 59.506 - How do I demonstrate compliance if I manufacture multi-component kits?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false How do I demonstrate compliance if I manufacture multi-component kits? 59.506 Section 59.506 Protection of Environment ENVIRONMENTAL PROTECTION... § 59.506 How do I demonstrate compliance if I manufacture multi-component kits? (a) If you...

  11. 40 CFR 59.506 - How do I demonstrate compliance if I manufacture multi-component kits?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false How do I demonstrate compliance if I manufacture multi-component kits? 59.506 Section 59.506 Protection of Environment ENVIRONMENTAL PROTECTION... § 59.506 How do I demonstrate compliance if I manufacture multi-component kits? (a) If you...

  12. Multi-component self-assembled anti-tumor nano-vaccines based on MUC1 glycopeptides.

    PubMed

    Sun, Z Y; Chen, P G; Liu, Y F; Zhang, B D; Wu, J J; Chen, Y X; Zhao, Y F; Li, Y M

    2016-06-18

    Novel multi-component self-assembled nano-vaccines containing both Pam3CSK4 and CpG were developed for the first time. These multi-component vaccines could effectively activate the macrophages in vitro and elicit strong antibody immune responses and anti-tumor immune responses in vivo. PMID:27216415

  13. Integrated ultracompact and broadband wavelength demultiplexer based on multi-component nano-cavities

    NASA Astrophysics Data System (ADS)

    Lu, Cuicui; Liu, Yong-Chun; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2016-06-01

    Integrated nanoscale photonic devices have wide applications ranging from optical interconnects and optical computing to optical communications. Wavelength demultiplexer is an essential on-chip optical component which can separate the incident wavelength into different channels; however, the experimental progress is very limited. Here, using a multi-component nano-cavity design, we realize an ultracompact, broadband and high-contrast wavelength demultiplexer, with 2.3 μm feature size, 200 nm operation bandwidth (from 780 nm to 980 nm) and a contrast ratio up to 13.7 dB. The physical mechanism is based on the strong modulation of the surface plasmon polaritons induced by the multi-component nano-cavities, and it can be generalized to other nanoscale photonic devices. This provides a strategy for constructing on-chip photon routers, and also has applications for chip-integrated optical filter and optical logic gates.

  14. Integrated ultracompact and broadband wavelength demultiplexer based on multi-component nano-cavities

    PubMed Central

    Lu, Cuicui; Liu, Yong-Chun; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2016-01-01

    Integrated nanoscale photonic devices have wide applications ranging from optical interconnects and optical computing to optical communications. Wavelength demultiplexer is an essential on-chip optical component which can separate the incident wavelength into different channels; however, the experimental progress is very limited. Here, using a multi-component nano-cavity design, we realize an ultracompact, broadband and high-contrast wavelength demultiplexer, with 2.3 μm feature size, 200 nm operation bandwidth (from 780 nm to 980 nm) and a contrast ratio up to 13.7 dB. The physical mechanism is based on the strong modulation of the surface plasmon polaritons induced by the multi-component nano-cavities, and it can be generalized to other nanoscale photonic devices. This provides a strategy for constructing on-chip photon routers, and also has applications for chip-integrated optical filter and optical logic gates. PMID:27263859

  15. Effect of composition on the density of multi-component molten nitrate salts.

    SciTech Connect

    Bradshaw, Robert W.

    2009-12-01

    The density of molten nitrate salts was measured to determine the effects of the constituents on the density of multi-component mixtures. The molten salts consisted of various proportions of the nitrates of potassium, sodium, lithium and calcium. Density measurements ere performed using an Archimedean method and the results were compared to data reported in the literature for the individual constituent salts or simple combinations, such as the binary Solar Salt mixture of NaNO3 and KNO3. The addition of calcium nitrate generally ncreased density, relative to potassium nitrate or sodium nitrate, while lithium nitrate decreased density. The temperature dependence of density is described by a linear equation regardless of composition. The molar volume, and thereby, density of multi-component mixtures an be calculated as a function of temperature using a linear additivity rule based on the properties of the individual constituents.

  16. Integrated ultracompact and broadband wavelength demultiplexer based on multi-component nano-cavities.

    PubMed

    Lu, Cuicui; Liu, Yong-Chun; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2016-01-01

    Integrated nanoscale photonic devices have wide applications ranging from optical interconnects and optical computing to optical communications. Wavelength demultiplexer is an essential on-chip optical component which can separate the incident wavelength into different channels; however, the experimental progress is very limited. Here, using a multi-component nano-cavity design, we realize an ultracompact, broadband and high-contrast wavelength demultiplexer, with 2.3 μm feature size, 200 nm operation bandwidth (from 780 nm to 980 nm) and a contrast ratio up to 13.7 dB. The physical mechanism is based on the strong modulation of the surface plasmon polaritons induced by the multi-component nano-cavities, and it can be generalized to other nanoscale photonic devices. This provides a strategy for constructing on-chip photon routers, and also has applications for chip-integrated optical filter and optical logic gates. PMID:27263859

  17. Permeation of multi-component liquids through new and pre-exposed glove materials

    SciTech Connect

    Forsberg, K.; Faniadis, S.

    1986-03-01

    Relative to the preponderance of multi-component solutions in industry, the availability of data on the barrier effectiveness of protective clothing to such solutions is minimal. The purpose of this study, therefore, was to measure the breakthrough times and permeation rates of 13 different multi-component liquids through 13 glove compositions. The solutions were selected to be representative of those in segments of the chemical and aircraft industries. The glove materials were tested as received and after one exposure to the liquids. The latter tests were designed to investigate factors associated with the reuse of gloves. Of the 8 basic glove materials, the butyl rubber and polyvinyl alcohol specimens exhibited the longest breakthrough times over the widest range of chemicals and chemical combinations.

  18. Whistler Emission and Absorption Coefficients from AN Anisotropic, Multi-Component Plasma Including Dielectric Response

    NASA Astrophysics Data System (ADS)

    Leid, Terrence Vincent

    The emission of electron cyclotron radiation parallel to the magnetic field direction near the fundamental frequency from a fully ionized, multi-component plasma, is investigated for finite (omega)(,p)/(omega)(,c) within the Klimontovich formalism. Each species may have T(,(PARLL)) different from T(,(PERP)) and may possess a loss cone. We use a bi- maxwellian with an analytic loss cone for each component. In addition, the source function for a multi-component plasma is calculated. We find that for a Maxwellian distribution function the emission coefficient is that of a system of shielded charges. It is shown that only in the case of a tenuous Maxwellian plasma is the source function the Rayleigh-Jeans blackbody intensity. For the case of the Maxwellian we present experimental evidence for finite density emission, (omega)('2)(,p)/(omega)('2) >> (beta). We have constructed a computer code that solves the radiative transfer equation. The resulting power spectra are used as an aid in extracting from experimental data the temperature and density of the various components of the TMX-Upgrade end cell plasma. The code compares both the Ellis-Tsakiris scheme for computing the emission coefficient for a multi-component plasma and the finite density multi -component emission coefficient. The Ellis- Tsakiris scheme estimates the emission coefficient by assuming. that each species radiates independently of each other.('1) Results are presented for the case of the TMX -Upgrade tandem mirror device. ('1)R. F. Ellis and G. D. Tsakiris, Nucl. Fusion 23, 1115 (1984).

  19. Constraint on the Multi-Component CKP Hierarchy and Recursion Operators

    NASA Astrophysics Data System (ADS)

    Song, Tao; Li, Chuanzhong; He, Jingsong

    2016-06-01

    In this article, we give the definition of the multi-component constrained CKP (McCKP) and two-component constrained CKP (cCKP) hierarchies (under the condition N=2). Then we give recursion operators for the two-component cCKP hierarchy. At last, we give the constrained condition from the two-component cCKP hierarchies to cCKP hierarchy.

  20. Impact of multi-component diffusion in turbulent combustion using direct numerical simulations

    SciTech Connect

    Bruno, Claudio; Sankaran, Vaidyanathan; Kolla, Hemanth; Chen, Jacqueline H.

    2015-08-28

    This study presents the results of DNS of a partially premixed turbulent syngas/air flame at atmospheric pressure. The objective was to assess the importance and possible effects of molecular transport on flame behavior and structure. To this purpose DNS were performed at with two proprietary DNS codes and with three different molecular diffusion transport models: fully multi-component, mixture averaged, and imposing the Lewis number of all species to be unity.

  1. Multi-component ground motion response spectra for coupled horizontal, vertical, angular accelerations, and tilt

    USGS Publications Warehouse

    Kalkan, E.; Graizer, V.

    2007-01-01

    Rotational and vertical components of ground motion are almost always ignored in design or in the assessment of structures despite the fact that vertical motion can be twice as much as the horizontal motion and may exceed 2g level, and rotational excitation may reach few degrees in the proximity of fault rupture. Coupling of different components of ground excitation may significantly amplify the seismic demand by introducing additional lateral forces and enhanced P-?? effects. In this paper, a governing equation of motion is postulated to compute the response of a SDOF oscillator under a multi-component excitation. The expanded equation includes secondary P-?? components associated with the combined impacts of tilt and vertical excitations in addition to the inertial forcing terms due to the angular and translational accelerations. The elastic and inelastic spectral ordinates traditionally generated considering the uniaxial input motion are compared at the end with the multi-component response spectra of coupled horizontal, vertical and tilting motions. The proposed multi-component response spectrum reflects kinematic characteristics of the ground motion that are not identifiable by the conventional spectrum itself, at least for the near-fault region where high intensity vertical shaking and rotational excitation are likely to occur.

  2. An immersed boundary-lattice Boltzmann method for single- and multi-component fluid flows

    NASA Astrophysics Data System (ADS)

    Li, Zhe; Favier, Julien; D'Ortona, Umberto; Poncet, Sébastien

    2016-01-01

    The paper presents a numerical method to simulate single- and multi-component fluid flows around moving/deformable solid boundaries, based on the coupling of Immersed Boundary (IB) and Lattice Boltzmann (LB) methods. The fluid domain is simulated with LB method using the single relaxation time BGK model, in which an interparticle potential model is applied for multi-component fluid flows. The IB-related force is directly calculated with the interpolated definition of the fluid macroscopic velocity on the Lagrangian points that define the immersed solid boundary. The present IB-LB method can better ensure the no-slip solid boundary condition, thanks to an improved spreading operator. The proposed method is validated through several 2D/3D single- and multi-component fluid test cases with a particular emphasis on wetting conditions on solid wall. Finally, a 3D two-fluid application case is given to show the feasibility of modeling the fluid transport via a cluster of beating cilia.

  3. Forward modelling of multi-component induction logging tools in layered anisotropic dipping formations

    NASA Astrophysics Data System (ADS)

    Gao, Jie; Xu, Chenhao; Xiao, Jiaqi

    2013-10-01

    Multi-component induction logging provides great assistance in the exploration of thinly laminated reservoirs. The 1D parametric inversion following an adaptive borehole correction is the key step in the data processing of multi-component induction logging responses. To make the inversion process reasonably fast, an efficient forward modelling method is necessary. In this paper, a modelling method has been developed to simulate the multi-component induction tools in deviated wells drilled in layered anisotropic formations. With the introduction of generalized reflection coefficients, the analytic expressions of magnetic field in the form of a Sommerfeld integral were derived. The fast numerical computation of the integral has been completed by using the fast Fourier-Hankel transform and fast Hankel transform methods. The latter is so time efficient that it is competent enough for real-time multi-parameter inversion. In this paper, some simulated results have been presented and they are in excellent agreement with the finite difference method code's solution.

  4. Structural and Thermodynamic Factors of Suppressed Interdiffusion Kinetics in Multi-component High-entropy Materials

    PubMed Central

    Chang, Shou-Yi; Li, Chen-En; Huang, Yi-Chung; Hsu, Hsun-Feng; Yeh, Jien-Wei; Lin, Su-Jien

    2014-01-01

    We report multi-component high-entropy materials as extraordinarily robust diffusion barriers and clarify the highly suppressed interdiffusion kinetics in the multi-component materials from structural and thermodynamic perspectives. The failures of six alloy barriers with different numbers of elements, from unitary Ti to senary TiTaCrZrAlRu, against the interdiffusion of Cu and Si were characterized, and experimental results indicated that, with more elements incorporated, the failure temperature of the barriers increased from 550 to 900°C. The activation energy of Cu diffusion through the alloy barriers was determined to increase from 110 to 163 kJ/mole. Mechanistic analyses suggest that, structurally, severe lattice distortion strains and a high packing density caused by different atom sizes, and, thermodynamically, a strengthened cohesion provide a total increase of 55 kJ/mole in the activation energy of substitutional Cu diffusion, and are believed to be the dominant factors of suppressed interdiffusion kinetics through the multi-component barrier materials. PMID:24561911

  5. A combustion model for IC engine combustion simulations with multi-component fuels

    SciTech Connect

    Ra, Youngchul; Reitz, Rolf D.

    2011-01-15

    Reduced chemical kinetic mechanisms for the oxidation of representative surrogate components of a typical multi-component automotive fuel have been developed and applied to model internal combustion engines. Starting from an existing reduced mechanism for primary reference fuel (PRF) oxidation, further improvement was made by including additional reactions and by optimizing reaction rate constants of selected reactions. Using a similar approach to that used to develop the reduced PRF mechanism, reduced mechanisms for the oxidation of n-tetradecane, toluene, cyclohexane, dimethyl ether (DME), ethanol, and methyl butanoate (MB) were built and combined with the PRF mechanism to form a multi-surrogate fuel chemistry (MultiChem) mechanism. The final version of the MultiChem mechanism consists of 113 species and 487 reactions. Validation of the present MultiChem mechanism was performed with ignition delay time measurements from shock tube tests and predictions by comprehensive mechanisms available in the literature. A combustion model was developed to simulate engine combustion with multi-component fuels using the present MultiChem mechanism, and the model was applied to simulate HCCI and DI engine combustion. The results show that the present multi-component combustion model gives reliable performance for combustion predictions, as well as computational efficiency improvements through the use of reduced mechanism for multi-dimensional CFD simulations. (author)

  6. A mesoscopic reaction rate model for shock initiation of multi-component PBX explosives.

    PubMed

    Liu, Y R; Duan, Z P; Zhang, Z Y; Ou, Z C; Huang, F L

    2016-11-01

    The primary goal of this research is to develop a three-term mesoscopic reaction rate model that consists of a hot-spot ignition, a low-pressure slow burning and a high-pressure fast reaction terms for shock initiation of multi-component Plastic Bonded Explosives (PBX). Thereinto, based on the DZK hot-spot model for a single-component PBX explosive, the hot-spot ignition term as well as its reaction rate is obtained through a "mixing rule" of the explosive components; new expressions for both the low-pressure slow burning term and the high-pressure fast reaction term are also obtained by establishing the relationships between the reaction rate of the multi-component PBX explosive and that of its explosive components, based on the low-pressure slow burning term and the high-pressure fast reaction term of a mesoscopic reaction rate model. Furthermore, for verification, the new reaction rate model is incorporated into the DYNA2D code to simulate numerically the shock initiation process of the PBXC03 and the PBXC10 multi-component PBX explosives, and the numerical results of the pressure histories at different Lagrange locations in explosive are found to be in good agreements with previous experimental data. PMID:27258213

  7. NOBLE GASES

    EPA Science Inventory

    The Noble Gases symposium, on which this report is based, provided comprehensive coverage of the noble gases. The coverage included, but was not limited to, the properties, biokinetics, bioeffects, production and release to the environment, detection techniques, standards, and ap...

  8. DESIGN, SYNTHESIS AND STUDY OF MULTI-COMPONENT AND INTEGRATED SYSTEMS FOR LIGHT-DRIVEN HYDROGEN GENERATION

    SciTech Connect

    Professor Richard Eisenberg

    2012-07-18

    successful in the development of synthetic methodologies to make multi-component systems designed so as to maintain electronic communication between components held in a defined spatial arrangement. Systems effective for light driven H2 generation were examined by photophysical methods including transient absorption spectroscopy to observe charge-separated states and chart their dynamics. Quantum yields for hydrogen production were also measured. Additional studies examined the effectiveness of these systems for H2 generation and involved the development of new catalysts and systems based thereon. From these studies, a better understanding of initial steps in the light driven generation of hydrogen were obtained.

  9. Multi-component boron coatings on low carbon steel AISI 1018

    NASA Astrophysics Data System (ADS)

    Suwattananont, Naruemon

    Boronizing and metalizing are thermo-chemical surface hardening treatments in which boron and metal atoms diffuse into the metal substrate forming metallic boride layers, providing complex properties of B-Me-Fe system. To study multi-component boron coatings on low carbon steel AISI 1018, the simultaneous powder pack method of boronizing and metalizing was selected to perform the coatings. One B-Fe system and eight boron-metal (B-Me-Fe) systems from transition metals group IVB (Ti, Zr, HO, group VB (Nb, Ta), and group VIB (Cr, Mo, W) were studied. The system specimens were thereto-chemically treated at 950°C for 4 hours in a crucible containing powder mixture of boron source, transition metal powder, and activator. After the heat treatment process, the multi-component boron coatings were characterized by using optical microscope, microhardness tester, TGA, XRD, and Synchrotron microdiffraction. The coating morphology was observed and the coating thickness was measured as well as the microhardness across the depth of coating. The corrosion resistance of the coatings was evaluated by the continuous weighting method. The high temperature oxidation was also detected by isothermal method at a temperature range of 400-800°C for 24 hours. The Rietveld refinement method was used to examine the quantitative phase analysis, crystalline size, microstrain and lattice parameters of the multi-component boron coatings. The results have shown that adding transition metals into the B-Fe system caused the formation of solid solution of transition-metal borides. The distortion of crystal lattice parameters generated microstrain in the boride phase. The Synchrotron microdiffraction confirmed the presence of about 5-10 microns of transition-metal boride phase at the surface. Moreover, the additional transition metal can provide better corrosion and high temperature oxidation resistance to the B-Fe system, preventing the deboronizing and stabilizing the boride phases.

  10. An analysis method for multi-component airfoils in separated flow

    NASA Technical Reports Server (NTRS)

    Rao, B. M.; Duorak, F. A.; Maskew, B.

    1980-01-01

    The multi-component airfoil program (Langley-MCARF) for attached flow is modified to accept the free vortex sheet separation-flow model program (Analytical Methods, Inc.-CLMAX). The viscous effects are incorporated into the calculation by representing the boundary layer displacement thickness with an appropriate source distribution. The separation flow model incorporated into MCARF was applied to single component airfoils. Calculated pressure distributions for angles of attack up to the stall are in close agreement with experimental measurements. Even at higher angles of attack beyond the stall, correct trends of separation, decrease in lift coefficients, and increase in pitching moment coefficients are predicted.

  11. Influence of Natural Convection and Thermal Radiation Multi-Component Transport in MOCVD Reactors

    NASA Technical Reports Server (NTRS)

    Lowry, S.; Krishnan, A.; Clark, I.

    1999-01-01

    The influence of Grashof and Reynolds number in Metal Organic Chemical Vapor (MOCVD) reactors is being investigated under a combined empirical/numerical study. As part of that research, the deposition of Indium Phosphide in an MOCVD reactor is modeled using the computational code CFD-ACE. The model includes the effects of convection, conduction, and radiation as well as multi-component diffusion and multi-step surface/gas phase chemistry. The results of the prediction are compared with experimental data for a commercial reactor and analyzed with respect to the model accuracy.

  12. A semi-discrete integrable multi-component coherently coupled nonlinear Schrödinger system

    NASA Astrophysics Data System (ADS)

    Zhao, Hai-qiong; Yuan, Jinyun

    2016-07-01

    A new integrable semi-discrete version is proposed for the multi-component coherently coupled nonlinear Schrödinger equation. The integrability of the semi-discrete system is confirmed by existence of Lax pair and infinite number of conservation laws. With the aid of gauge transformations, explicit formulas for N-fold Darboux transformations are derived whereby some physically important solutions of the system are presented. Furthermore, the theory of the semi-discrete system including Lax pair, Darboux transformations, exact solutions and infinite number of conservation laws are shown for their continuous counterparts in the continuous limit.

  13. Novel multi-component hybrids through double luminescent lanthanide unit functionalized zeolite L and titania.

    PubMed

    Chen, Lei; Yan, Bing

    2015-12-01

    Zeolite L (ZL) is functionalized with inside-outside double modification paths (gas disperse ("ship in bottle") and covalently grafting) with two kinds of luminescent lanthanide species (Tb(3+) complex of acetylacetone (AA), lanthanide polyoxometalate (NaLnW10O36·32H2O, abbreviated as LnW10, Ln=Eu, Tb)) to prepare the hybrid materials. The prepared hybrids show the red and green luminescence, which provides a useful path to obtain multi-component lanthanide hybrids. PMID:26125989

  14. AEROFROSH: a shock condition calculator for multi-component fuel aerosol-laden flows

    NASA Astrophysics Data System (ADS)

    Campbell, M. F.; Haylett, D. R.; Davidson, D. F.; Hanson, R. K.

    2015-08-01

    This article introduces an algorithm that determines the thermodynamic conditions behind incident and reflected shocks in aerosol-laden flows. Importantly, the algorithm accounts for the effects of droplet evaporation on post-shock properties. Additionally, this article describes an algorithm for resolving the effects of multiple-component-fuel droplets. This article presents the solution methodology and compares the results to those of another similar shock calculator. It also provides examples to show the impact of droplets on post-shock properties and the impact that multi-component fuel droplets have on shock experimental parameters. Finally, this paper presents a detailed uncertainty analysis of this algorithm's calculations given typical experimental uncertainties.

  15. Line of critical points in 2+1 dimensions: quantum critical loop gases and non-Abelian gauge theory.

    PubMed

    Freedman, Michael; Nayak, Chetan; Shtengel, Kirill

    2005-04-15

    In this Letter, we (1) construct a one-parameter family of lattice models of interacting spins; (2) obtain their exact ground states; (3) derive a statistical-mechanical analogy which relates their ground states to O(n) loop gases; (4) show that the models are critical for d

  16. Removal of bacterial indicators and pathogens from dairy wastewater by a multi-component treatment system.

    PubMed

    Karpiscak, M M; Sanchez, L R; Freitas, R J; Gerba, C P

    2001-01-01

    Microbial removal by a multi-component treatment system for dairy and municipal wastewater is being studied in Arizona, USA. The system consists of paired solids separators, anaerobic lagoons, aerobic ponds and constructed wetlands cells. The organisms under study include: total coliform, fecal coliform, enterovirus, Listeria monocytogenes, Clostridium perfringens, coliphage, Giardia lamblia and Cryptosporidium parvum. Organism removal rates from dairy wastewater varied from 13.2 per cent for fecal coliform to 94.9 per cent for coliphage. It appears that the much higher turbidity of the dairy wastewater, nearly 1,300 NTU, decreased the treatment systems' ability to remove some microbial indicators and pathogens. Information from this study can be used to determine the adequacy of multi-component treatment systems for the control of wastewater-borne pathogens, both in municipal treatment systems as well as in confined animal feeding operations (CAFO). This information also can assist municipalities and the CAFO industry in the implementation of rational and efficient treatment strategies for appropriate reuse of wastewaters. PMID:11804092

  17. A Robust MEMS Based Multi-Component Sensor for 3D Borehole Seismic Arrays

    SciTech Connect

    Paulsson Geophysical Services

    2008-03-31

    The objective of this project was to develop, prototype and test a robust multi-component sensor that combines both Fiber Optic and MEMS technology for use in a borehole seismic array. The use such FOMEMS based sensors allows a dramatic increase in the number of sensors that can be deployed simultaneously in a borehole seismic array. Therefore, denser sampling of the seismic wave field can be afforded, which in turn allows us to efficiently and adequately sample P-wave as well as S-wave for high-resolution imaging purposes. Design, packaging and integration of the multi-component sensors and deployment system will target maximum operating temperature of 350-400 F and a maximum pressure of 15000-25000 psi, thus allowing operation under conditions encountered in deep gas reservoirs. This project aimed at using existing pieces of deployment technology as well as MEMS and fiber-optic technology. A sensor design and analysis study has been carried out and a laboratory prototype of an interrogator for a robust borehole seismic array system has been assembled and validated.

  18. A new pulsed laser deposition technique: scanning multi-component pulsed laser deposition method.

    PubMed

    Fischer, D; de la Fuente, G F; Jansen, M

    2012-04-01

    The scanning multi-component pulsed laser deposition (PLD) method realizes uniform depositions of desired coatings by a modified pulsed laser deposition process, preferably with a femto-second laser-system. Multi-component coatings (single or multilayered) are thus deposited onto substrates via laser induced ablation of segmented targets. This is achieved via horizontal line-scanning of a focused laser beam over a uniformly moving target's surface. This process allows to deposit the desired composition of the coating simultaneously, starting from the different segments of the target and adjusting the scan line as a function of target geometry. The sequence and thickness of multilayers can easily be adjusted by target architecture and motion, enabling inter/intra layer concentration gradients and thus functional gradient coatings. This new, simple PLD method enables the achievement of uniform, large-area coatings. Case studies were performed with segmented targets containing aluminum, titanium, and niobium. Under the laser irradiation conditions applied, all three metals were uniformly ablated. The elemental composition within the rough coatings obtained was fixed by the scanned area to Ti-Al-Nb = 1:1:1. Crystalline aluminum, titanium, and niobium were found to coexist side by side at room temperature within the substrate, without alloy formation up to 600 °C. PMID:22559543

  19. Numerical investigation of spray ignition of a multi-component fuel surrogate

    NASA Astrophysics Data System (ADS)

    Backer, Lara; Narayanaswamy, Krithika; Pepiot, Perrine

    2014-11-01

    Simulating turbulent spray ignition, an important process in engine combustion, is challenging, since it combines the complexity of multi-scale, multiphase turbulent flow modeling with the need for an accurate description of chemical kinetics. In this work, we use direct numerical simulation to investigate the role of the evaporation model on the ignition characteristics of a multi-component fuel surrogate, injected as droplets in a turbulent environment. The fuel is represented as a mixture of several components, each one being representative of a different chemical class. A reduced kinetic scheme for the mixture is extracted from a well-validated detailed chemical mechanism, and integrated into the multiphase turbulent reactive flow solver NGA. Comparisons are made between a single-component evaporation model, in which the evaporating gas has the same composition as the liquid droplet, and a multi-component model, where component segregation does occur. In particular, the corresponding production of radical species, which are characteristic of the ignition of individual fuel components, is thoroughly analyzed.

  20. Directing folding pathways for multi-component DNA origami nanostructures with complex topology

    NASA Astrophysics Data System (ADS)

    Marras, A. E.; Zhou, L.; Kolliopoulos, V.; Su, H.-J.; Castro, C. E.

    2016-05-01

    Molecular self-assembly has become a well-established technique to design complex nanostructures and hierarchical mesoscale assemblies. The typical approach is to design binding complementarity into nucleotide or amino acid sequences to achieve the desired final geometry. However, with an increasing interest in dynamic nanodevices, the need to design structures with motion has necessitated the development of multi-component structures. While this has been achieved through hierarchical assembly of similar structural units, here we focus on the assembly of topologically complex structures, specifically with concentric components, where post-folding assembly is not feasible. We exploit the ability to direct folding pathways to program the sequence of assembly and present a novel approach of designing the strand topology of intermediate folding states to program the topology of the final structure, in this case a DNA origami slider structure that functions much like a piston-cylinder assembly in an engine. The ability to program the sequence and control orientation and topology of multi-component DNA origami nanostructures provides a foundation for a new class of structures with internal and external moving parts and complex scaffold topology. Furthermore, this work provides critical insight to guide the design of intermediate states along a DNA origami folding pathway and to further understand the details of DNA origami self-assembly to more broadly control folding states and landscapes.

  1. Upscaling multi-component reactive transport in presence of connected subsurface structures

    NASA Astrophysics Data System (ADS)

    Willmann, M.; Mañé, R.; Tyukhova, A.

    2015-12-01

    Heterogeneity in hydraulic conductivity leads to incomplete mixing. Upscaling using the dispersion tensor in the advection-dispersion equation overestimates local mixing. Modelling multi-component reactive transport leads to an overestimation of reaction rates and overall reactions. Multi-rate mass transfer was shown previously to better represent mixing. But it is still unclear under what conditions this linear model is able to represent the underlying non-linear process. We study explicit multi-component transport in heterogeneous aquifers for the example of calcite-dissolution. We compare different types of heterogeneity from intermediately well connected (multigaussian) fields to very well connected fields. The fundamental difference stems from their connectivity structure. We observe for the well connected field different dominating channels with an almost uniform advective velocity while the multigaussian fields show dominating channels with a varying advective velocity. Then, we compare our results with an effective reactive mass transfer model where the distribution of exchanges rates or the memory function are derived from information of the hydraulic conductivity field only. We see that reactive multi-rate models show a good agreement for the well connected fields where the connected channels are more or less homogeneous and the immobile inclusions are of more or less equal size. We find connectivity important for upscaling reactive transport in highly heterogeneous conductivity fields.

  2. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1990-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra-efficient and low-emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttria based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  3. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2003-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra efficient and low emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttna based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  4. Multi-component Wronskian solution to the Kadomtsev-Petviashvili equation

    NASA Astrophysics Data System (ADS)

    Xu, Tao; Sun, Fu-Wei; Zhang, Yi; Li, Juan

    2014-01-01

    It is known that the Kadomtsev-Petviashvili (KP) equation can be decomposed into the first two members of the coupled Ablowitz-Kaup-Newell-Segur (AKNS) hierarchy by the binary non-linearization of Lax pairs. In this paper, we construct the N-th iterated Darboux transformation (DT) for the second- and third-order m-coupled AKNS systems. By using together the N-th iterated DT and Cramer's rule, we find that the KPII equation has the unreduced multi-component Wronskian solution and the KPI equation admits a reduced multi-component Wronskian solution. In particular, based on the unreduced and reduced two-component Wronskians, we obtain two families of fully-resonant line-soliton solutions which contain arbitrary numbers of asymptotic solitons as y → ∓∞ to the KPII equation, and the ordinary N-soliton solution to the KPI equation. In addition, we find that the KPI line solitons propagating in parallel can exhibit the bound state at the moment of collision.

  5. Multi-component molecular-level body composition reference methods: evolving concepts and future directions.

    PubMed

    Heymsfield, S B; Ebbeling, C B; Zheng, J; Pietrobelli, A; Strauss, B J; Silva, A M; Ludwig, D S

    2015-04-01

    Excess adiposity is the main phenotypic feature that defines human obesity and that plays a pathophysiological role in most chronic diseases. Measuring the amount of fat mass present is thus a central aspect of studying obesity at the individual and population levels. Nevertheless, a consensus is lacking among investigators on a single accepted 'reference' approach for quantifying fat mass in vivo. While the research community generally relies on the multi-component body volume class of 'reference' models for quantifying fat mass, no definable guide discerns among different applied equations for partitioning the four (fat, water, protein and mineral mass) or more quantified components, standardizes 'adjustment' or measurement system approaches for model-required labelled water dilution volumes and bone mineral mass estimates, or firmly establishes the body temperature at which model physical properties are assumed. The resulting differing reference strategies for quantifying body composition in vivo leads to small, but under some circumstances, important differences in the amount of measured body fat. Recent technological advances highlight opportunities to expand model applications to new subject groups and measured components such as total body protein. The current report reviews the historical evolution of multi-component body volume-based methods in the context of prevailing uncertainties and future potential. PMID:25645009

  6. A level set simulation of dendritic solidification of multi-component alloys

    NASA Astrophysics Data System (ADS)

    Tan, Lijian; Zabaras, Nicholas

    2007-01-01

    A level set method combining features of front tracking methods and fixed domain methods is presented to model microstructure evolution in the solidification of multi-component alloys. Phase boundaries are tracked by solving the multi-phase level set equations. Diffused interfaces are constructed from these tracked phase boundaries using the level set functions. Based on the assumed diffused interfaces, volume-averaging techniques are applied for energy, species and momentum transport. Microstructure evolution in multi-component alloy systems is predicted using realistic material parameters. The methodology avoids the difficulty of parameter identification needed in other diffused interface models, and allows easy application to various practical alloy systems. Techniques including fast marching, narrow band computing and adaptive meshing are utilized to speed up computations. Several numerical examples are considered to validate the method and examine its potential for modeling solidification of practical alloy systems. These examples include two- and three-dimensional solidification of a binary alloy in an undercooled melt, a study of planar/cellular/dendritic transition in the solidification of a Ni-Cu alloy, and eutectic and peritectic solidification of an Fe-C system. Adaptive mesh refinement in the rapidly varying interface region makes the method practical for coupling the microstructure evolution at the meso-scale with buoyancy driven flow in the macro-scale, which is shown in the solidification of a Ni-Al-Ta ternary alloy.

  7. A new pulsed laser deposition technique: Scanning multi-component pulsed laser deposition method

    SciTech Connect

    Fischer, D.; Jansen, M.; Fuente, G. F. de la

    2012-04-15

    The scanning multi-component pulsed laser deposition (PLD) method realizes uniform depositions of desired coatings by a modified pulsed laser deposition process, preferably with a femto-second laser-system. Multi-component coatings (single or multilayered) are thus deposited onto substrates via laser induced ablation of segmented targets. This is achieved via horizontal line-scanning of a focused laser beam over a uniformly moving target's surface. This process allows to deposit the desired composition of the coating simultaneously, starting from the different segments of the target and adjusting the scan line as a function of target geometry. The sequence and thickness of multilayers can easily be adjusted by target architecture and motion, enabling inter/intra layer concentration gradients and thus functional gradient coatings. This new, simple PLD method enables the achievement of uniform, large-area coatings. Case studies were performed with segmented targets containing aluminum, titanium, and niobium. Under the laser irradiation conditions applied, all three metals were uniformly ablated. The elemental composition within the rough coatings obtained was fixed by the scanned area to Ti-Al-Nb = 1:1:1. Crystalline aluminum, titanium, and niobium were found to coexist side by side at room temperature within the substrate, without alloy formation up to 600 deg. C.

  8. Bloch oscillation, dynamical localization, and optical probing of electron gases in quantum-dot superlattices in high electric fields

    NASA Astrophysics Data System (ADS)

    Huang, Danhong; Lyo, S. K.; Gumbs, Godfrey

    2009-04-01

    In this paper, we present numerical results for steady-state and time-dependent currents as well as for a long-time average current in strong nonlinear dc and ac electric fields for an electron gas in a one-dimensional (1D) quantum-dot superlattice. A microscopic model is employed for the scattering of electrons by phonons and static impurities by means of the Boltzmann equation method. The dc results are favorably compared with recent exact analytic results based on a relaxation-time model for electron-phonon scattering. Our results demonstrate the different roles played by elastic and inelastic scattering on the damped Bloch oscillations as well as the nonlinear steady-state current and their opposite roles on the damped dynamical localization. We also find a suppression of dynamical localization by strong Bloch oscillations and features in the Esaki-Tsu peaks in the presence of an ac electric field when electron scattering is included. On the basis of a nonequilibrium electron distribution obtained from the Boltzmann equation, a self-consistent-field approach is employed to establish a general formalism for the optical response of current-driven electrons in both the linear and nonlinear regimes to a 1D quantum-dot superlattice. The dc-field dependences of both the peak energy and peak strength in the absorption spectrum for a 1D quantum-dot superlattice are calculated, from which we find: (1) both the peak energy and its strength are significantly reduced with increasing dc electric field; and (2) the peak energy and peak strength are anomalously enhanced by raising the temperature for the nonlinear transport of electrons when a strong dc electric field is applied.

  9. Optically trapped quasi-two-dimensional Bose gases in a random environment: Quantum fluctuations and superfluid density

    SciTech Connect

    Zhou Kezhao; Liang Zhaoxin; Zhang Zhidong; Hu Ying

    2010-10-15

    We investigate a dilute Bose gas confined in a tight one-dimensional (1D) optical lattice plus a superimposed random potential at zero temperature. Accordingly, the ground-state energy, quantum depletion, and superfluid density are calculated. The presence of the lattice introduces a crossover to the quasi-two-dimensional (2D) regime, where we analyze asymptotically the 2D behavior of the system, particularly the effects of disorder. We thereby offer an analytical expression for the ground-state energy of a purely 2D Bose gas in a random potential. The obtained disorder-induced normal fluid density n{sub n} and quantum depletion n{sub d} both exhibit a characteristic 1/ln(1/n{sub 2D}a{sub 2D}{sup 2}) dependence. Their ratio n{sub n}/n{sub d} increases to 2 compared to the familiar 4/3 in lattice-free three-dimensional (3D) geometry, signifying a more pronounced contrast between superfluidity and Bose-Einstein condensation in low dimensions. The conditions for possible experimental realization of our scenario are also proposed.

  10. Sensitive detection of CO2 concentration and temperature for hot gases using quantum-cascade laser absorption spectroscopy near 4.2 μm

    NASA Astrophysics Data System (ADS)

    Wu, Kuijun; Li, Faquan; Cheng, Xuewu; Yang, Yong; Lin, Xin; Xia, Yuan

    2014-06-01

    Mid-infrared quantum-cascade laser (QCL) absorption spectroscopy of CO2 near 4.2 μm has been developed for measurement of temperature and concentration in hot gases. With stronger absorption line-strengths than transitions near 1.5, 2.0, and 2.7 μm used previously, the fundamental band (0001-0000) of CO2 near 4.2 μm provides greatly enhanced sensitivity and accuracy to sense CO2 in high-temperature gases. Line R(74) and line R(96) are chosen as optimum pair for sensitive temperature measurements due to their high-temperature sensitivity, equal signal-to-noise ratio (SNR), weak interference of H2O transitions, as well as relatively strong line-strengths in high temperature and weak absorption in room temperature. The high-resolution absorption spectrum of the far wings of the R-branch (R56-R100) in the fundamental vibrational band of CO2 is measured in a heated cell over the range 2,384-2,396 cm-1 at different temperatures from 700 to 1,200 K. Taking three factors into consideration, including SNR, concentration detectability, and uncertainty sensitivity, the absorption line R(74) is selected to calculate CO2 concentration. The tunable QCL absorption sensor is validated in mixtures of CO2 and N2 in a static cell for temperature range of 700-1,200 K, achieving an accuracy of ±6 K for temperature and ±5 % for concentration measurements.

  11. Spin-orbit coupling in GaxIn1-xAs/InP two-dimensional electron gases and quantum wire structures

    NASA Astrophysics Data System (ADS)

    Schäpers, Th; Guzenko, V. A.; Bringer, A.; Akabori, M.; Hagedorn, M.; Hardtdegen, H.

    2009-06-01

    In this work, the effect of spin-orbit coupling in two-dimensional electron gases and quantum wire structures is discussed. First, the theoretical framework is introduced including spin-orbit coupling due to structural inversion asymmetry, the so-called Rashba effect, as well as the Dresselhaus term. The latter originates from bulk inversion asymmetry. With regard to wire structures, special attention is devoted to the influence of the particular shape of the confinement potential on the energy spectrum. As a model system GaxIn1-xAs/InP heterostructures are chosen, where different thicknesses of the strained Ga0.23In0.77As channel layer were introduced, in order to adjust the strength of the spin-orbit coupling. Hall bar structures as well as sets of identical wires with different widths were prepared. In two-dimensional electron gases, the strength of the spin-orbit coupling was extracted by analyzing the characteristic beating pattern in the Shubnikov-de Haas oscillations. In addition, the weak antilocalization was utilized to obtain information on the spin-orbit coupling. It is shown that for decreasing width of the strained layer the Rashba effect, which dominates in our layer systems, is increased. This behavior is attributed to the larger interface contribution if the electron wavefunction is strongly confined. The measurements on the wire structures revealed a transition from weak antilocalization to weak localization if the wire width is decreased. This effect is attributed to an enhanced spin diffusion length for strongly confined systems.

  12. Quantum Monte Carlo method for pairing phenomena: Supercounterfluid of two-species Bose gases in optical lattices

    SciTech Connect

    Ohgoe, Takahiro; Kawashima, Naoki

    2011-02-15

    We study the supercounterfluid (SCF) states in the two-component hard-core Bose-Hubbard model on a square lattice, using the quantum Monte Carlo method based on the worm (directed-loop) algorithm. Since the SCF state is a state of a pair condensation characterized by {ne}0,=0, and =0, where a and b are the order parameters of the two components, it is important to study behaviors of the pair-correlation function . For this purpose, we propose a choice of the worm head for calculating the pair-correlation function. From this pair correlation, we confirm the Kosterlitz-Thouless character of the SCF phase. The simulation efficiency is also improved in the SCF phase.

  13. Quantum Monte Carlo method for pairing phenomena: Supercounterfluid of two-species Bose gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Ohgoe, Takahiro; Kawashima, Naoki

    2011-02-01

    We study the supercounterfluid (SCF) states in the two-component hard-core Bose-Hubbard model on a square lattice, using the quantum Monte Carlo method based on the worm (directed-loop) algorithm. Since the SCF state is a state of a pair condensation characterized by ≠0,=0, and =0, where a and b are the order parameters of the two components, it is important to study behaviors of the pair-correlation function . For this purpose, we propose a choice of the worm head for calculating the pair-correlation function. From this pair correlation, we confirm the Kosterlitz-Thouless character of the SCF phase. The simulation efficiency is also improved in the SCF phase.

  14. A finite element method based microwave heat transfer modeling of frozen multi-component foods

    NASA Astrophysics Data System (ADS)

    Pitchai, Krishnamoorthy

    Microwave heating is fast and convenient, but is highly non-uniform. Non-uniform heating in microwave cooking affects not only food quality but also food safety. Most food industries develop microwavable food products based on "cook-and-look" approach. This approach is time-consuming, labor intensive and expensive and may not result in optimal food product design that assures food safety and quality. Design of microwavable food can be realized through a simulation model which describes the physical mechanisms of microwave heating in mathematical expressions. The objective of this study was to develop a microwave heat transfer model to predict spatial and temporal profiles of various heterogeneous foods such as multi-component meal (chicken nuggets and mashed potato), multi-component and multi-layered meal (lasagna), and multi-layered food with active packages (pizza) during microwave heating. A microwave heat transfer model was developed by solving electromagnetic and heat transfer equations using finite element method in commercially available COMSOL Multiphysics v4.4 software. The microwave heat transfer model included detailed geometry of the cavity, phase change, and rotation of the food on the turntable. The predicted spatial surface temperature patterns and temporal profiles were validated against the experimental temperature profiles obtained using a thermal imaging camera and fiber-optic sensors. The predicted spatial surface temperature profile of different multi-component foods was in good agreement with the corresponding experimental profiles in terms of hot and cold spot patterns. The root mean square error values of temporal profiles ranged from 5.8 °C to 26.2 °C in chicken nuggets as compared 4.3 °C to 4.7 °C in mashed potatoes. In frozen lasagna, root mean square error values at six locations ranged from 6.6 °C to 20.0 °C for 6 min of heating. A microwave heat transfer model was developed to include susceptor assisted microwave heating of a

  15. Effectiveness of multi-component non-pharmacologic delirium interventions: A Meta-analysis

    PubMed Central

    Hshieh, Tammy T.; Yue, Jirong; Oh, Esther; Puelle, Margaret; Dowal, Sarah; Travison, Thomas; Inouye, Sharon K.

    2015-01-01

    Importance Delirium, an acute disorder with high morbidity and mortality, is often preventable through multi-component non-pharmacologic strategies. The efficacy of these strategies for preventing subsequent adverse outcomes has been limited to small studies. Objective Evaluate available evidence on multi-component non-pharmacologic delirium interventions in reducing incident delirium and preventing poor outcomes associated with delirium. Data Sources PubMed, Google Scholar, ScienceDirect and Cochrane Database of Systematic Reviews from January 1, 1999–December 31, 2013. Study Selection Studies examining the following outcomes were included: delirium incidence, falls, length of stay, rate of discharge to a long-term care institution, change in functional or cognitive status. Data Extraction and Synthesis Two experienced physician reviewers independently and blindly abstracted data on outcome measures using a standardized approach. The reviewers conducted quality ratings based on the Cochrane Risk of Bias criteria for each study. Main Outcomes and Measures We identified 14 interventional studies. Results for outcomes of delirium, falls, length of stay and institutionalization data were pooled for meta-analysis but heterogeneity limited meta-analysis of results for outcomes of functional and cognitive decline. Overall, eleven studies demonstrated significant reductions in delirium incidence (Odds Ratio 0.47, 95% Confidence Interval 0.38–0.58). The four randomized or matched (RMT) studies reduced delirium incidence by 44% (95% CI 0.42–0.76). Rate of falls decreased significantly among intervention patients in four studies (OR 0.38, 95% CI 0.25–0.60); in the two RMTs, the fall rate was reduced by 64% (95% CI 0.22–0.61). Lengths of stay and institutionalization rates also trended towards decreases in the intervention groups, mean difference −0.16 days shorter (95% CI −0.97–0.64) and odds of institutionalization 5% lower (OR 0.95, 95% CI 0.71–1

  16. Multi-component nanofibrous scaffolds with tunable properties for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Jose, Moncy V.

    Bone is a highly complex tissue which is an integral part of vertebrates and hence any damage has a major negative effect on the quality of life. Tissue engineering is regarded as an ideal route to resolve the issues related to the scarcity of tissue and organ for transplantation. Apart from cell line and growth factors, the choice of materials and fabrication technique for scaffold are equally important. The goal of this work was to develop a multi-component nanofibrous scaffold based on a synthetic polymer (poly(lactic-co-glycolide) (PLGA)), a biopolymer (collagen) and a biomineral (nano-hydroxyapatite (nano-HA)) by electrospinning technique, which mimics the nanoscopic, chemical, and anisotropic features of bone. Preliminary studies involved fabrication of nanocomposite scaffolds based on PLGA and nano-HA. Morphological and mechanical characterizations revealed that at low concentrations, nano-HA acted as reinforcements, whereas at higher concentrations the presence of aggregation was detrimental to the scaffold. Hydrolytic degradation studies revealed the scaffold had a little mass loss and the mechanical property was maintained for a period of 6 weeks. This study was followed by evaluation of a blend system based on PLGA and collagen. Collagen addition provides hydrophilicity and the necessary cell binding sites in PLGA. The structural characterization revealed that the blend had limited interactions between the two components. The mechanical characterization revealed that with increasing collagen concentration, there was a decline in mechanical properties. However, crosslinking of the blend system, with carbodiimide (EDC) resulted in improving the mechanical properties of the scaffolds. A multi-component system was developed by adding different concentrations of nano-HA to a fixed PLGA/collagen blend composition (80/20). Morphological and mechanical characterizations revealed properties similar to the PLGA/HA system. Cyto-compatibility studies revealed

  17. Exact solution of Smoluchowski's continuous multi-component equation with an additive kernel

    NASA Astrophysics Data System (ADS)

    Fernández-Díaz, J. M.; Gómez-García, G. J.

    2007-06-01

    Smoluchowski's equation is used to analyse the dynamics of particulate systems under aggregation processes in aerosol physics, atmospheric physics, astrophysics, polymer chemistry, colloidal chemistry, etc. Here we provide an exact analytical solution for Smoluchowski's general, continuous, multi-component equation with additive kernel, for any initial particle size distribution (PSD). Once obtained the general solution, we apply it to a case with initial gamma PSD, which can be used to test numerical methods developed for solving more general cases. We have analysed the behaviour for large sizes and time, and a scaling approximation has been obtained as Vigil and Ziff conjectured. For bi-component mixtures we prove that as time increases, for the additive kernel, we cannot use the scaling solution to describe the behaviour of the number PSD on the whole. This fact contradicts a recent affirmation on the subject done by Matsoukas et al.

  18. Dispersion relation of electrostatic ion cyclotron waves in multi-component magneto-plasma

    SciTech Connect

    Khaira, Vibhooti Ahirwar, G.

    2015-07-31

    Electrostatic ion cyclotron waves in multi component plasma composed of electrons (denoted by e{sup −}), hydrogen ions (denoted by H{sup +}), helium ions (denoted by He{sup +}) and positively charged oxygen ions (denoted by O{sup +})in magnetized cold plasma. The wave is assumed to propagate perpendicular to the static magnetic field. It is found that the addition of heavy ions in the plasma dispersion modified the lower hybrid mode and also allowed an ion-ion mode. The frequencies of the lower hybrid and ion- ion hybrid modes are derived using cold plasma theory. It is observed that the effect of multi-ionfor different plasma densities on electrostatic ion cyclotron waves is to enhance the wave frequencies. The results are interpreted for the magnetosphere has been applied parameters by auroral acceleration region.

  19. Single-pulse Multi-point Multi-component Interferometric Rayleigh Scattering Velocimeter

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Lee, Joseph W.; Gaffney, Richard L., Jr.; Cutler, Andrew W.

    2006-01-01

    A simultaneous multi-point, multi-component velocimeter using interferometric detection of the Doppler shift of Rayleigh, Mie, and Rayleigh-Brillouin scattered light in supersonic flow is described. The system uses up to three sets of collection optics and one beam combiner for the reference laser light to form a single collimated beam. The planar Fabry-Perot interferometer used in the imaging mode for frequency detection preserves the spatial distribution of the signal reasonably well. Single-pulse multi-points measurements of up to two orthogonal and one non-orthogonal components of velocity in a Mach 2 free jet were performed to demonstrate the technique. The average velocity measurements show a close agreement with the CFD calculations using the VULCAN code.

  20. Multi-component dark matter in the light of new AMS-02 data

    NASA Astrophysics Data System (ADS)

    Lai, Chang; Huang, Da; Geng, Chao-Qiang

    2015-10-01

    We study the possible positron/electron excesses within the multi-component leptonically decaying dark matter (DM) scenario by fitting the most recent AMS-02 data on the positron fraction and total e+ + e- flux. We show that both the single- and two-component DM models are able to fit the two AMS-02 datasets. However, the single-component DM model favors the e+/e- energy cutoff from the DM decay less than 1 TeV through the τ-channel, which is already well constrained by the diffuse γ-ray spectrum measured by Fermi-LAT. For the two-component case with closing the τ-mode for the heavy DM particle, we find that the new AMS-02 data allows the heavy DM cutoff larger than 1 TeV, providing a good description of the high-energy behavior of the total e+ + e- flux and satisfying the diffuse γ-ray constraint.

  1. Unsupervised color image segmentation using graph cuts with multi-components

    NASA Astrophysics Data System (ADS)

    Li, Lei; Jin, Lianghai; Song, Enmin; Dong, Zhuoli

    2013-10-01

    A novel unsupervised color image segmentation method based on graph cuts with multi-components is proposed, which finds an optimal segmentation of an image by regarding it as an energy minimization problem. First, L*a*b* color space is chosen as color feature, and the multi-scale quaternion Gabor filter is employed to extract texture feature of the given image. Then, the segmentation is formulated in terms of energy minimization with an iterative process based on graph cuts, and the connected regions in each segment are considered as the components of the segment in each iteration. In addition, canny edge detector combined with color gradient is used to remove weak edges in segmentation results with the proposed algorithm. In contrast to previous algorithms, our method could greatly reduce computational complexity during inference procedure by graph cuts. Experimental results demonstrate the promising performance of the proposed method.

  2. Dynamic Multi-Component Covalent Assembly for the Reversible Binding of Secondary Alcohols and Chirality Sensing

    PubMed Central

    You, Lei; Berman, Jeffrey S.; Anslyn, Eric V.

    2011-01-01

    Reversible covalent bonding is often employed for the creation of novel supramolecular structures, multi-component assemblies, and sensing ensembles. In spite of remarkable success of dynamic covalent systems, the reversible binding of a mono-alcohol with high strength is challenging. Here we show that a strategy of carbonyl activation and hemiaminal ether stabilization can be embodied in a four-component reversible assembly that creates a tetradentate ligand and incorporates secondary alcohols with exceptionally high affinity. Evidence is presented that the intermediate leading to binding and exchange of alcohols is an iminium ion. Further, to demonstrate the use of this assembly process we explored chirality sensing and enantiomeric excess determinations. An induced twist in the ligand by a chiral mono-ol results in large Cotton effects in the circular dichroism spectra indicative of the alcohol’s handedness. The strategy revealed in this study should prove broadly applicable for the incorporation of alcohols into supramolecular architecture construction. PMID:22109274

  3. Recent advances on multi-component hybrid nanostructures for electrochemical capacitors

    NASA Astrophysics Data System (ADS)

    Xiong, Pan; Zhu, Junwu; Wang, Xin

    2015-10-01

    With the continuously growing energy demand and ever-escalating environmental problems, the great energy transition from conventional fossil fuels to renewable sources of energy is under way, and requires more efficient and reliable electrochemical energy storage devices, such as electrochemical capacitors (also called as supercapacitors). In order to achieve high energy and power densities of supercapacitors, numerous efforts are devoted to the development of advanced multi-component hybrid electrode materials for realizing high-performance. This review summarizes the most recent progress in the development of nanostructured electrode materials for energy storage, with a particular focus on these nanostructures that integrate carbon materials, metal oxides/hydroxides and conducting polymers for enhancing energy storage performances via taking advantage of each component's unique functionality and their synergetic effects. Finally, we give some perspectives on the challenges and opportunities in this intriguing field.

  4. Coupling Multi-Component Models with MPH on Distributed MemoryComputer Architectures

    SciTech Connect

    He, Yun; Ding, Chris

    2005-03-24

    A growing trend in developing large and complex applications on today's Teraflop scale computers is to integrate stand-alone and/or semi-independent program components into a comprehensive simulation package. One example is the Community Climate System Model which consists of atmosphere, ocean, land-surface and sea-ice components. Each component is semi-independent and has been developed at a different institution. We study how this multi-component, multi-executable application can run effectively on distributed memory architectures. For the first time, we clearly identify five effective execution modes and develop the MPH library to support application development utilizing these modes. MPH performs component-name registration, resource allocation and initial component handshaking in a flexible way.

  5. Assessing the state of environmental quality in cities - A multi-component urban performance (EMCUP) index.

    PubMed

    Stossel, Zeev; Kissinger, Meidad; Meir, Avinoam

    2015-11-01

    Urban environmental quality indices can provide policy makers and the public with valuable information. However, common assessment tools have several shortcomings: most indices do leave out some important components of the state of urban environmental quality; they use a relative assessment in which urban environmental performance is evaluated relative to other cities, not against established environmental benchmarks; and only a few assessment tools compare urban performance to environmental quality standards. This paper presents a new multi component urban performance (EMCUP) index aiming to tackle those shortcomings. It analyses the overall state of urban environmental quality by using a list of indicators to evaluate key urban environmental quality topics such as air, water, open space, sanitation and solid waste. It presents an absolute score calculated in relation to both the standard and desired optimum levels. The use of the index is demonstrated by three Israeli cities. PMID:26334706

  6. Accurate design of co-assembling multi-component protein nanomaterials

    NASA Astrophysics Data System (ADS)

    King, Neil P.; Bale, Jacob B.; Sheffler, William; McNamara, Dan E.; Gonen, Shane; Gonen, Tamir; Yeates, Todd O.; Baker, David

    2014-06-01

    The self-assembly of proteins into highly ordered nanoscale architectures is a hallmark of biological systems. The sophisticated functions of these molecular machines have inspired the development of methods to engineer self-assembling protein nanostructures; however, the design of multi-component protein nanomaterials with high accuracy remains an outstanding challenge. Here we report a computational method for designing protein nanomaterials in which multiple copies of two distinct subunits co-assemble into a specific architecture. We use the method to design five 24-subunit cage-like protein nanomaterials in two distinct symmetric architectures and experimentally demonstrate that their structures are in close agreement with the computational design models. The accuracy of the method and the number and variety of two-component materials that it makes accessible suggest a route to the construction of functional protein nanomaterials tailored to specific applications.

  7. [Fluorescence emission spectra of petroleumsulfonate and OP-10 in multi-components aqueous solutions].

    PubMed

    Bi, Z; Ye, J; Yu, J

    1998-06-01

    The determination of surfactant(s) in the alkaline/surfactant/polymer flooding solutions was an uneasy job. For this purpose, the method of fluorescence emission by phenoxy-containing surfactants in dilute solutions is suggested. The fluorescence emission intensity changes linearly with in the extent of low surfactant concentrations below the critical micelle concentration (CMC) and is not influenced by the presence of alkali, polymer PHPAM and salts. Under certain conditions the fluorescence emission by petroleum sulfonate and OP-10 in a multi-components aqueous solution can be detected independently. This method is high-selective, sensitive (the lowest detectable concentration 10(-7) mol/L) and microanalytical (the amount of test solution 2-3 microL). PMID:15810288

  8. SCOUSE: Semi-automated multi-COmponent Universal Spectral-line fitting Engine

    NASA Astrophysics Data System (ADS)

    Henshaw, J. D.; Longmore, S. N.; Kruijssen, J. M. D.; Davies, B.; Bally, J.; Barnes, A.; Battersby, C.; Burton, M.; Cunningham, M. R.; Dale, J. E.; Ginsburg, A.; Immer, K.; Jones, P. A.; Kendrew, S.; Mills, E. A. C.; Molinari, S.; Moore, T. J. T.; Ott, J.; Pillai, T.; Rathborne, J.; Schilke, P.; Schmiedeke, A.; Testi, L.; Walker, D.; Walsh, A.; Zhang, Q.

    2016-01-01

    The Semi-automated multi-COmponent Universal Spectral-line fitting Engine (SCOUSE) is a spectral line fitting algorithm that fits Gaussian files to spectral line emission. It identifies the spatial area over which to fit the data and generates a grid of spectral averaging areas (SAAs). The spatially averaged spectra are fitted according to user-provided tolerance levels, and the best fit is selected using the Akaike Information Criterion, which weights the chisq of a best-fitting solution according to the number of free-parameters. A more detailed inspection of the spectra can be performed to improve the fit through an iterative process, after which SCOUSE integrates the new solutions into the solution file.

  9. A solid-state NMR method to determine domain sizes in multi-component polymer formulations

    NASA Astrophysics Data System (ADS)

    Schlagnitweit, Judith; Tang, Mingxue; Baias, Maria; Richardson, Sara; Schantz, Staffan; Emsley, Lyndon

    2015-12-01

    Polymer domain sizes are related to many of the physical properties of polymers. Here we present a solid-state NMR experiment that is capable of measuring domain sizes in multi-component mixtures. The method combines selective excitation of carbon magnetization to isolate a specific component with proton spin diffusion to report on domain size. We demonstrate the method in the context of controlled release formulations, which represents one of today's challenges in pharmaceutical science. We show that we can measure domain sizes of interest in the different components of industrial pharmaceutical formulations at natural isotopic abundance containing various (modified) cellulose derivatives, such as microcrystalline cellulose matrixes that are film-coated with a mixture of ethyl cellulose (EC) and hydroxypropyl cellulose (HPC).

  10. Diffusion in multi-component polymeric systems: Diffusion of non-volatile species in thin films

    NASA Astrophysics Data System (ADS)

    Müller, M.; Kind, M.; Cairncross, R.; Schabel, W.

    2009-01-01

    Polymeric films for high-tech products like LCD-panels, transdermal patches or medical test strips typically consist of a polymer and one or more non-volatile additives. If during the production process a multi-component solution is coated and subsequently dried, the diffusion of solvents and non-volatile species in the polymeric systems plays an important role. Recent experiments revealed that the drying conditions can have a significant influence on the formation of inhomogeneous distribution of the non-volatile components in the final foil and therefore affects desired product properties. The distribution of the non-volatile components in the final film has an important impact on the physical and chemical properties, including mechanical and optical properties, wetting behavior or drug release rates i.e. the product quality of the polymeric system. To be able to describe the diffusion of non-volatile species in a multi-component polymeric system during drying correctly, reliable information about the influence of the solvent concentration on the mobility of the additive are essential. To obtain information about the mobility of the additive in the polymeric solution new experiments were performed and observed by means of Inverse-Micro-Raman-Spectroscopy (IMRS). By fitting simulated concentration profiles to the experimental data, the temperature and concentration dependent diffusion coefficient of the non-volatile additive in the polymer solution was determined. The investigations are part of a bilateral funding of NFG in the US and DFG in Germany. Diffusion of volatile species in multicomponent polymeric systems are investigated by the group of Richard Cairncross.

  11. Examining multi-component DNA-templated nanostructures as imaging agents

    NASA Astrophysics Data System (ADS)

    Jaganathan, Hamsa

    2011-12-01

    Magnetic resonance imaging (MRI) is the leading non-invasive tool for disease imaging and diagnosis. Although MRI exhibits high spatial resolution for anatomical features, the contrast resolution is low. Imaging agents serve as an aid to distinguish different types of tissues within images. Gadolinium chelates, which are considered first generation designs, can be toxic to health, while ultra-small, superparamagnetic nanoparticles (NPs) have low tissue-targeting efficiency and rapid bio-distribution, resulting to an inadequate detection of the MRI signal and enhancement of image contrast. In order to improve the utility of MRI agents, the challenge in composition and structure needs to be addressed. One-dimensional (1D), superparamagnetic nanostructures have been reported to enhance magnetic and in vivo properties and therefore has a potential to improve contrast enhancement in MRI images. In this dissertation, the structure of 1D, multi-component NP chains, scaffolded on DNA, were pre-clinically examined as potential MRI agents. First, research was focused on characterizing and understanding the mechanism of proton relaxation for DNA-templated NP chains using nuclear magnetic resonance (NMR) spectrometry. Proton relaxation and transverse relaxivity were higher in multi-component NP chains compared to disperse NPs, indicating the arrangement of NPs on a 1D structure improved proton relaxation sensitivity. Second, in vitro evaluation for potential issues in toxicity and contrast efficiency in tissue environments using a 3 Tesla clinical MRI scanner was performed. Cell uptake of DNA-templated NP chains was enhanced after encapsulating the nanostructure with layers of polyelectrolytes and targeting ligands. Compared to dispersed NPs, DNA-templated NP chains improved MRI contrast in both the epithelial basement membrane and colon cancer tumors scaffolds. The last part of the project was focused on developing a novel MRI agent that detects changes in DNA methylation

  12. Measuring Chern numbers in Atomic Gases: 2D and 4D Quantum Hall Physics in the Lab

    NASA Astrophysics Data System (ADS)

    Goldman, Nathan

    Optical-lattice experiments have recently succeeded in probing the geometry of 2D Bloch bands with cold neutral atoms. Beyond these local geometrical effects, which are captured by the Berry curvature, 2D Bloch bands may also display non-trivial topology, a global property captured by a topological invariant (e.g. the first Chern number). Such topological properties have dramatic consequences on the transport of non-interacting atoms, such as quantized responses whenever the bands are uniformly populated. In this talk, I will start with the first experimental demonstration of topological transport in a gas of neutral particles, which revealed the Chern number through a cold-atom analogue of quantum-Hall measurements. I will then describe how this Chern-number measurement could be extended in order to probe the topology of higher-dimensional systems. In particular, I will show how the second Chern number - an emblematic topological invariant associated with 4D Bloch bands - could be extracted from an atomic gas, using a 3D optical lattice extended by a synthetic dimension. Finally, I will describe a general scheme by which optical lattices of subwavelength spacing could be realized. This method leads to topological band structures with significantly enhanced energy scales, offering an interesting route towards the experimental realization of strongly-correlated topological states with cold atoms.

  13. Greenhouse Gases

    MedlinePlus

    ... Greenhouse Gases Come From Outlook for Future Emissions Recycling and Energy Nonrenewable Sources Oil and Petroleum Products ... Power Wave Power Ocean Thermal Energy Conversion Biomass Wood and Wood Waste Waste-to-Energy (MSW) Landfill ...

  14. An Integrated Multi-component Processing and Interpretation Framework for 3D Borehole Seismic Data

    SciTech Connect

    M. Karrenbach

    2004-04-01

    This report covers the October 2003 until March 2004 time period. Work has continued successfully on several tasks 1 through 7. Most of these tasks have been executed independently. Due to availability of manpower during that time period we progressed steadily and completed some of the tasks, while others are still on going. We achieved the goals that we had set up in the task schedule. Reviewing the results of this work period indicates that our plan is on schedule and we did not encounter any unforeseen problems. The work plan will continue as projected. Several independent tasks pursuant the statement of project objectives have been executed simultaneously and are still on-going. This report summarizes the selection, test processing and test flow generation of a relevant 3D borehole seismic high-resolution test dataset. This multi-component data set is suitable for future use in this project due to data quality and unique acquisition characteristics. This report shows initial processing results that supported the data selection scheduled for Task 1. Use of real data is augmented by the creating a 3D layered synthetic geologic model in which multi-component 3D borehole seismic data were generated using 3D ray tracing. A gridded surface representation of the reflection interfaces as well as fully populated velocity grids were generated and archived. The model consists of a moderately dipping geologic setting with horizon undulations. A realistic velocity variation is used in between the three layers. Acquisition was simulated from a set of equidistant source locations at the surface of the model, while a close to vertical VSP well was used to capture the wave field data. The source pattern was close to a staggered grid pattern. Multi-component particle displacements were recorded every 50 ft down with an array length of 4,000 ft. P-P as well as P-S reflections were specified in the resulting wave field. We ensured a large enough aperture with enough fine sampling

  15. Development of Ocean Bottom Multi-component Seismic System for Methane Hydrate Dissociation Monitoring

    NASA Astrophysics Data System (ADS)

    Takahashi, H.; Asakawa, E.; Hayashi, T.; Inamori, T.; Saeki, T.

    2011-12-01

    A 2D multi-component seismic survey was carried out in the Nankai Trough using the RSCS (Real-time Seismic Cable System) system in 2006. The RSCS is the newly developed ocean bottom cable system which is usable in more than 2000m water depth. The results of the PP and data PS components gave us much information of the methane hydrates bearing zone. Based on RSCS technology, we are developing a new monitoring system using multi-component seismic sensors to delineate the methane hydrate dissociation zone for the offshore methane hydrate production test scheduled in FY2012. Conventional RSCS is composed of three component gimbaled geophones which require a large volume inside the receiver. We will adopt accelerometers to achieve a small receiver that is 2/3 the size of conventional RSCS. The accelerometer data can be corrected into horizontal or vertical directions based on the gravity acceleration. The receiver case has a protective metallic exterior and the cable is protected with steel-screened armoring, allowing for burial usage using ROV for sub-seabed deployment. It will realize a unique survey style that leaves the system on the seabed between pre-test baseline survey and post-test repeated survey, which might be up to 6 months. The fixed location of the receiver is very important for time-lapse monitoring survey. We name the new system as DSS (Deep-sea Seismic System). A feasibility study to detect the methane hydrate dissociation with the DSS was carried out and we found that the methane hydrate dissociation could be detected with the DSS depending on the area of the dissociation. The first experiment of the DSS performance test in a marine area is planned in November 2011. The main features of DSS are described as follows: (1) Deep-sea /Ultra Deep-sea Operation Methane hydrate exists in equilibrium temperature and pressure holds at water depths greater than 500m. The system water depth resistance target up to 2000m. The receiver case has a protective

  16. Feshbach resonances in ultracold gases

    SciTech Connect

    Chin Cheng; Grimm, Rudolf; Julienne, Paul; Tiesinga, Eite

    2010-04-15

    Feshbach resonances are the essential tool to control the interaction between atoms in ultracold quantum gases. They have found numerous experimental applications, opening up the way to important breakthroughs. This review broadly covers the phenomenon of Feshbach resonances in ultracold gases and their main applications. This includes the theoretical background and models for the description of Feshbach resonances, the experimental methods to find and characterize the resonances, a discussion of the main properties of resonances in various atomic species and mixed atomic species systems, and an overview of key experiments with atomic Bose-Einstein condensates, degenerate Fermi gases, and ultracold molecules.

  17. Wavelength-modulation-spectroscopy for real-time, in situ NO detection in combustion gases with a 5.2 μm quantum-cascade laser

    NASA Astrophysics Data System (ADS)

    Chao, X.; Jeffries, J. B.; Hanson, R. K.

    2012-03-01

    A mid-infrared absorption strategy with calibration-free wavelength-modulation-spectroscopy (WMS) has been developed and demonstrated for real-time, in situ detection of nitric oxide in particulate-laden combustion-exhaust gases up to temperatures of 700 K. An external-cavity quantum-cascade laser (ECQCL) near 5.2 μm accessed the fundamental absorption band of NO, and a wavelength-scanned, 1 f-normalized WMS with second-harmonic detection (WMS-2 f/1 f) strategy was developed. Due to the external-cavity laser architecture, large nonlinear intensity modulation (IM) was observed when the wavelength was modulated by injection-current modulation, and the IM indices were also found to be strongly wavelength-dependent as the center wavelength was scanned with piezoelectric tuning of the cavity. A quantitative model of the 1 f-normalized WMS-2 f signal was developed and validated under laboratory conditions. A sensor was subsequently designed, built and demonstrated for real-time, in situ measurements of NO across a 3 m path in the particulate-laden exhaust of a pulverized-coal-fired power plant boiler. The 1 f-normalized WMS-2 f method proved to have better noise immunity for non-absorption transmission, than wavelength-scanned direct absorption. A 0.3 ppm-m detection limit was estimated using the R15.5 transition near 1927 cm-1 with 1 s averaging. Mid-infrared QCL-based NO absorption with 1 f-normalized WMS-2 f detection shows excellent promise for practical sensing in the combustion exhaust.

  18. Intracellular trafficking and exocytosis of a multi-component siRNA nanocomplex.

    PubMed

    Shukla, Ravi S; Jain, Akshay; Zhao, Zhen; Cheng, Kun

    2016-07-01

    Despite the importance of siRNA delivery systems, understanding of their intracellular fate remains elusive. We recently developed a multi-component siRNA nanocomplex to deliver siRNA to hepatic stellate cells (HSCs). The objective of this study is to study post-internalization trafficking of this siRNA nanocomplex and its multiple components like siRNA, protamine, and streptavidin, in HSCs. After internalization, the nanocomplex entrapped in early endosomes undergoes three possible routes including endosomal escape, exocytosis, and entrapment in lysosomes. Significant amount of siRNA dissociates from the nanocomplex to exert silencing activity. After escaping from endosomes, protamine dissociates from the nanocomplex and stays inside the cytoplasm. Golgi complex plays an important role in exocytosis of the nanocomplex. We also demonstrate that exocytosis is one of the major reasons accounting for the transient silencing activity of nonviral siRNA delivery. Incorporation of exocytosis inhibitors in nonviral siRNA delivery systems may extend the silencing activity of siRNA. PMID:26970028

  19. Self-Assembling Multi-Component Nanofibers for Strong Bioinspired Underwater Adhesives

    PubMed Central

    Zhong, Chao; Gurry, Thomas; Cheng, Allen A; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M.; Lu, Timothy K

    2014-01-01

    Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly, and structure-function relationship of those natural amyloid fibers remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibers. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibers have an underwater adhesion energy approaching 20.9 mJ/m2, which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibers taken on their own at all pHs and exhibit better tolerance to auto-oxidation than Mfps at pH ≥7.0. This work establishes a platform for engineering multi-component self-assembling materials inspired by nature. PMID:25240674

  20. A multi-component two-phase flow algorithm for use in landfill processes modelling.

    PubMed

    White, J K; Nayagum, D; Beaven, R P

    2014-09-01

    This paper describes the finite difference algorithm that has been developed for the flow sub-model of the University of Southampton landfill degradation and transport model LDAT. The liquid and gas phase flow components are first decoupled from the solid phase of the full multi-phase, multi-component landfill process constitutive equations and are then rearranged into a format that can be applied as a calculation procedure within the framework of a three dimensional array of finite difference rectangular elements. The algorithm contains a source term which accommodates the non-flow landfill processes of degradation, gas solubility, and leachate chemical equilibrium, sub-models that have been described in White and Beaven (2013). The paper includes an illustration of the application of the flow sub-model in the context of the leachate recirculation tests carried out at the Beddington landfill project. This illustration demonstrates the ability of the sub-model to track movement in the gas phase as well as the liquid phase, and to simulate multi-directional flow patterns that are different in each of the phases. PMID:24925875

  1. Energy loss behavior of photo-generated multi-component carriers in GaN

    NASA Astrophysics Data System (ADS)

    Yi, Kyung-Soo; Kim, Hye Jung; Kim, Do-Kyun

    2014-03-01

    Temporal behavior and many-body effect on the energy losses of photo-generated electron-hole plasma in GaN are examined in terms of various carrier-phonon couplings. We report a comprehensive cooling behavior as a function of effective carrier temperature over the temperature range of 10 -1500 K for carrier-phonon couplings via polar and nonpolar optical phonons and piezoelectric and acoustic deformation-potentials. The many-body effect on the multi-component carrier polarizations and phonon spectral function and effect of energy reabsorption via hot phonons are included by employing temperature-dependent dynamic responses in the rpa. We show that, as the carrier temperature decreases, the energy losses via carrier-optical phonon couplings diminish rapidly and the carrier energy relaxation is dominated through the acoustic phonon scattering at low carrier energy. From the energy loss rates, energy cooling curves are obtained as a function of time, and our result shows an initial gentle energy relaxation followed by fast relaxation. Spectral analysis of the dielectric response functions and energy loss rates are also performed and their dynamic and nonlocal behavior will be discussed. This research was supported in part by Basic Science Research Program through the NRF funded by the Ministry of Education (grant number 201306330001).

  2. Modeling solute redistribution and microstructural development in fusion welds of multi-component alloys

    SciTech Connect

    Dupont, J.N.; Robino, C.V.; Newbury, B.D.

    1999-12-15

    Solute redistribution and microstructural evolution have been modeled for gas tungsten arc fusion welds in experimental Ni base superalloys. The multi-component alloys were modeled as a pseudo-ternary {gamma}-Nb-C system. The variation in fraction liquid and liquid composition during the primary L {r{underscore}arrow} {gamma} and eutectic type L {r{underscore}arrow} ({gamma} + NbC) stages of solidification were calculated for conditions of negligible Nb diffusion and infinitely rapid C diffusion in the solid phase. Input parameters were estimated by using the Thermo-Calc NiFe Alloy data base and compared to experimentally determined solidification parameters. The solidification model results provide useful information for qualitatively interpreting the influence of alloy composition on weld microstructure. The quantitative comparisons indicate that, for the alloy system evaluated, the thermodynamic database provides sufficiently accurate values for the distribution coefficients of Nb and C. The calculated position of the {gamma}-NbC two-fold saturation line produces inaccurate results when used as inputs for the model, indicating further refinement to the database is needed for quantitative estimates.

  3. Real-Space Approach to Electronic Structure and Stability in Multi-Component Alloys.

    NASA Astrophysics Data System (ADS)

    Turchi, P. E. A.; Mayou, D.; Julien, J. P.

    1996-03-01

    A recently developed real-space approach based on the extended recursion technique and the coherent potential approximation is applied to solve a tight-binding Hamiltonian which describes chemical disorder in multi-component alloys. Effective interactions as defined in the embedded cluster method, and which describe ordering tendencies in alloys, are also obtained with this real-space approach combined with an "orbital peeling" technique. After a formal introduction, the results of this new approach in terms of densities of states, band-energies and effective interactions are presented for pseudo-binary and ternary transition metal alloys characterized by spd-electrons. The results compare extremely well with those obtained by a standard k-space method. Formal and practical advantages of this new approach, and in particular its application to the study of amorphous alloys will be discussed. Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48. Partial support from NATO under contract No. CRG-941028 is gratefully acknowledged.

  4. [CoCuMnOx Photocatalyzed Oxidation of Multi-component VOCs and Kinetic Analysis].

    PubMed

    Meng, Hai-long; Bo, Long-li; Liu, Jia-dong; Gao, Bo; Feng, Qi-qi; Tan, Na; Xie, Shuai

    2016-05-15

    Solar energy absorption coating CoCuMnOx was prepared by co-precipitation method and applied to photodegrade multi- component VOCs including toluene, ethyl acetate and acetone under visible light irradiation. The photocatalytic oxidation performance of toluene, ethyl acetate and acetone was analyzed and reaction kinetics of VOCs were investigated synchronously. The research indicated that removal rates of single-component toluene, ethyl acetate and acetone were 57%, 62% and 58% respectively under conditions of 400 mg · m⁻³ initial concentration, 120 mm illumination distance, 1 g/350 cm² dosage of CoCuMnOx and 6 h of irradiation time by 100 W tungsten halogen lamp. Due to the competition among different VOCs, removal efficiencies in three-component mixture were reduced by 5%-26% as compared with single VOC. Degradation processes of single-component VOC and three-component VOCs both fitted pseudo first order reaction kinetics, and kinetic constants of toluene, ethyl acetate and acetone were 0.002, 0.002 8 and 0.002 33 min⁻¹ respectively under single-component condition. Reaction rates of VOCs in three-component mixture were 0.49-0.88 times of single components. PMID:27506018

  5. Low Frequency Turbulence as the Source of High Frequency Waves in Multi-Component Space Plasmas

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.; Krivorutsky, Emmanuel N.; Uritsky, Vadim M.

    2011-01-01

    Space plasmas support a wide variety of waves, and wave-particle interactions as well as wavewave interactions are of crucial importance to magnetospheric and ionospheric plasma behavior. High frequency wave turbulence generation by the low frequency (LF) turbulence is restricted by two interconnected requirements: the turbulence should be strong enough and/or the coherent wave trains should have the appropriate length. These requirements are strongly relaxed in the multi-component plasmas, due to the heavy ions large drift velocity in the field of LF wave. The excitation of lower hybrid waves (LHWs), in particular, is a widely discussed mechanism of interaction between plasma species in space and is one of the unresolved questions of magnetospheric multi-ion plasmas. It is demonstrated that large-amplitude Alfven waves, in particular those associated with LF turbulence, may generate LHW s in the auroral zone and ring current region and in some cases (particularly in the inner magnetosphere) this serves as the Alfven wave saturation mechanism. We also argue that the described scenario can playa vital role in various parts of the outer magnetosphere featuring strong LF turbulence accompanied by LHW activity. Using the data from THEMIS spacecraft, we validate the conditions for such cross-scale coupling in the near-Earth "flow-braking" magnetotail region during the passage of sharp injection/dipolarization fronts, as well as in the turbulent outflow region of the midtail reconnection site.

  6. Electrostatic envelope modes in multi-component non-thermal plasmas

    NASA Astrophysics Data System (ADS)

    Saiful Islam, Md; Sultana, Sharmin; Mamun, A. A.

    2016-07-01

    A theoretical study of envelope type solitary structures and their modulational instability has been made in a multi-component unmagnetized non-thermal plasma (consisting of negatively charged immobile heavy ions, inertial light ions and non-thermal electrons of two distinct temperatures). The cubic nonlinear Schrödinger equation (which describes the evolution of a slowly varying wave envelope with space and time) is derived by adopting the multiple scale (in space and time) perturbation technique. It is found that the plasma system under consideration supports two types (bright and dark) envelope solitons. It is also seen that the dark (bright) envelope solitons are modulationally stable (unstable). The variation of the growth rate of the unstable bright envelope solitons with various plasma parameters (e.g. wave number, temperature of plasma non-thermality, etc.) are found to be significant. The modulational instability criterions of the envelope modes are also seen to be influenced due to the variation of the intrinsic plasma parameters. This theoretical study may be useful in understanding the basic features of localized electrostatic structures in some space plasma systems (viz. Saturn's magnetosphere) where high energetic particles are available.

  7. Photogrammetric Deflection Measurements for the Tiltrotor Test Rig (TTR) Multi-Component Rotor Balance Calibration

    NASA Technical Reports Server (NTRS)

    Solis, Eduardo; Meyn, Larry

    2016-01-01

    Calibrating the internal, multi-component balance mounted in the Tiltrotor Test Rig (TTR) required photogrammetric measurements to determine the location and orientation of forces applied to the balance. The TTR, with the balance and calibration hardware attached, was mounted in a custom calibration stand. Calibration loads were applied using eleven hydraulic actuators, operating in tension only, that were attached to the forward frame of the calibration stand and the TTR calibration hardware via linkages with in-line load cells. Before the linkages were installed, photogrammetry was used to determine the location of the linkage attachment points on the forward frame and on the TTR calibration hardware. Photogrammetric measurements were used to determine the displacement of the linkage attachment points on the TTR due to deflection of the hardware under applied loads. These measurements represent the first photogrammetric deflection measurements to be made to support 6-component rotor balance calibration. This paper describes the design of the TTR and the calibration hardware, and presents the development, set-up and use of the photogrammetry system, along with some selected measurement results.

  8. Development of multi-component explosive lenses for arbitrary phase velocity generation

    NASA Astrophysics Data System (ADS)

    Loiseau, Jason; Huneault, Justin; Petel, Oren; Goroshin, Sam; Frost, David; Higgins, Andrew; Zhang, Fan

    2013-06-01

    The combination of explosives with different detonation velocities and lens-like geometric shaping is a well-established technique for producing structured detonation waves. This technique can be extended to produce nearly arbitrary detonation phase velocities for the purposes of sequentially imploding pressurized tubes or driving Mach disks through high-density metalized explosives. The current study presents the experimental development of accelerating, multi-component lenses designed using simple geometric optics and idealized front curvature. The fast explosive component is either Composition C4 (VOD = 8 km/s) or Primasheet 1000 (VOD = 7 km/s), while the slow component varies from heavily amine-diluted nitromethane (amine mass fraction exceeding 20%) to packed metal and glass particle beds wetted with amine-sensitized nitromethane. The applicability of the geometric optic analog to such highly heterogeneous explosives is also investigated. The multi-layered lens technique is further developed as a means of generating a directed mass and momentum flux of metal particles via Mach-disk formation and jetting in circular and oval planar lenses.

  9. Evaporation of multi-component mixtures and shell formation in spray dried droplets

    NASA Astrophysics Data System (ADS)

    Valente, Pedro; Duarte, Íris; Porfirio, Tiago; Temtem, Márcio

    2015-11-01

    Drug particles where the active pharmaceutical ingredient (APIs) is dispersed in a polymer matrix forming an amorphous solid dispersion (ASD) is a commonly used strategy to increase the solubility and dissolution rate of poorly water soluble APIs. However, the formation and stability of an amorphous solid dispersion depends on the polymer/API combination and process conditions to generate it. The focus of the present work is to further develop a numerical tool to predict the formation of ASDs by spray drying solutions of different polymer/API combinations. Specifically, the evaporation of a multi-component droplet is coupled with a diffusion law within the droplet that minimizes the Gibbs free energy of the polymer/API/solvents system, following the Flory-Huggins model. Prior to the shell formation, the evaporation of the solvents is modelled following the simplified approach proposed by Abramzon & Sirignano (1989) which accounts for the varying relative velocity between the droplet and the drying gas. After shell formation, the diffusion of the solvents across the porous shell starkly modifies the evaporative dynamics.

  10. A multi-component meningococcal serogroup B vaccine (4CMenB): the clinical development program.

    PubMed

    O'Ryan, Miguel; Stoddard, Jeffrey; Toneatto, Daniela; Wassil, James; Dull, Peter M

    2014-01-01

    Recently approved in Europe and Australia, the multi-component meningococcal B vaccine, 4CMenB (Bexsero®, Novartis Vaccines and Diagnostics), contains three surface-exposed recombinant proteins (fHbp, NadA, and NHBA) and New Zealand strain outer membrane vesicles (NZ OMV) with PorA 1.4 antigenicity. This comprehensive review of the 4CMenB clinical development program covers pivotal phase I/IIb/III studies in over 7,000 adults, adolescents, and infants. The immunological correlate for clinical protection used was human complement-mediated serum bactericidal activity titers ≥4 or 5 against indicator strains for individual antigens. Based on achievement of protective titers, a four-dose schedule (three primary doses and one booster dose) for infants and a two-dose schedule for adolescents provided the best results. Observed increases in injection site pain/tenderness and fever in infants, and injection site pain, malaise, and headache in adolescents compared with routine vaccines, were mostly mild to moderate; frequencies of rare events (Kawasaki disease, juvenile arthritis) were not significantly different from non-vaccinated individuals. 4CMenB is conservatively estimated to provide 66-91 % coverage against meningococcal serogroup B strains worldwide. PMID:24338083

  11. Hygroscopicity of internally mixed multi-component aerosol particles of atmospheric relevance

    NASA Astrophysics Data System (ADS)

    Liu, Qifan; Jing, Bo; Peng, Chao; Tong, Shengrui; Wang, Weigang; Ge, Maofa

    2016-01-01

    The hygroscopic properties of two water-soluble organic compounds (WSOCs) relevant to urban haze pollution (phthalic acid and levoglucosan) and their internally mixtures with inorganic salts (ammonium sulfate and ammonium nitrate) are investigated using a hygroscopicity tandem differential mobility analyzer (H-TDMA) system. The multi-component particles uptake water gradually in the range 5-90% relative humidity (RH). The experimental results are compared with the thermodynamic model predictions. For most mixtures, Extended Aerosol Inorganic Model (E-AIM) predictions agree well with the measured growth factors. The hygroscopic growth of mixed particles can be well described by the Zdanovskii-Stokes-Robinson (ZSR) relation as long as the mixed particles are completely liquid. ZSR calculations underestimate the water uptake of mixed particles at moderate RH due to the partial dissolution of ammonium sulfate in the organic and ammonium nitrate solution in this RH region. The phase of ammonium nitrate in the initial dry particles changes dramatically with the composition of mixtures. The presence of organics in the mixed particles can inhibit the crystallization of ammonium nitrate during the drying process and results in water uptake at low RH (RH < 60%). These results demonstrate that certain representative WSOCs can substantially influence the hygroscopicity of inorganic salts and overall water uptake of particles.

  12. Intermolecular interactions in multi-component crystals of acridinone/thioacridinone derivatives: Structural and energetics investigations

    NASA Astrophysics Data System (ADS)

    Wera, Michał; Storoniak, Piotr; Trzybiński, Damian; Zadykowicz, Beata

    2016-12-01

    A single crystal X-ray analysis of two multi-component crystals consisting of an acridinone/thioacridinone moiety and a solvent moiety - water and ammonia (1 and 2), respectively, was carried out to determine the crystal structures of obtained crystals. A theoretical approach was undertaken - using the DFT method, lattice energies calculations and Hirshfeld surfaces (HS) - to qualitatively and quantitatively assess the intermolecular interactions within the crystal. HS analysis was showed that the H⋯H, C⋯H/H⋯C and C⋯C contacts for both structures (altogether 81.6% of total Hirshfeld surface area for 1 and 79.3% for 2) and the O⋯H/H⋯O (14.3%) for 1 and the S⋯H/H⋯S (15.2%) contacts for 2 were the characteristic intermolecular contacts in the related crystal structures. Using a computational methods were confirmed that the main contribution to the stabilization of the crystal lattice of compound 1 comes from the Coulombic interactions, whereas in compound 2 electrostatic and van der Waals appear to have similar contribution to the crystal lattice energy. Theoretical calculations of the investigated compounds have also allowed to determine the energy of a single specific intermolecular interaction.

  13. MuSPAC: Near surface characterization with multi-component surface wave correlations (Invited)

    NASA Astrophysics Data System (ADS)

    Lamb, A.; van Wijk, K.; Liberty, L. M.

    2013-12-01

    We present a modification of the Spatial Autocorrelation (SPAC) method that improves surface wave dispersion estimates. Existing methods to retrieve vital near-surface properties generally use only the vertical components. We demonstrate the advantages of the Multi-Component SPAC, here termed MuSPAC, by using both the vertical and radial components of the measured wavefield to calculate phase velocity dispersion curves. Through simplifying the method for the 1D case we use cosine and sine functions, as opposed to Bessel functions, to enable us to calculate four SPAC coefficients. We apply our method to numerical elastic wave simulations for a known source and earth model of increasing complexity. We then apply our method to a field case and examine how successfully we can retrieve the velocity structure of the earth model. We show that we can successfully retrieve phase velocities for both numerical and field based data using the MuSPAC method. Through it's use of interferometry with two wavefield components, the methods advantages over existing surface wave techniques include: 1) the addition of three dispersion curves to reduce error, 2) the enhancement of the signal to noise ratio through summation of sources and, 3) the ability to use any source term.

  14. A Multi-Component Model that Describes Weak Detonation in Blast Explosives

    NASA Astrophysics Data System (ADS)

    Stewart, D. Scott; Asay, Blaine; Bdzil, John; Foster, Joseph; Hernández, Alberto; Lambert, David

    2015-06-01

    Recently our group proposed a conceptual, multi-component model of an explosive material that admits weak (sonic) detonation. The weak detonation has the property that its propagation speed and wave structure is a function of the reaction rate of decomposition of reactants to products. The simplest version of the model assumes that a blast explosive has three components, reactants, intermediates and products. For many cases of interest this model is applicable if the first step is an endothermic reaction to intermediates followed by an exothermic reaction to products. Analysis shows that the properties of the weak detonation depend on the ratio of the first and second reaction rates. The decomposition steps, each can be endothermic or exothermic, but the overall reaction must be exothermic. We present both a theoretical and an engineering analysis of a typical explosive in this class and demonstrate by means of accompanying numerical simulations, that a three component reactive flow model that has a fast exothermic step to intermediates, followed by a slower endothermic step to final products produces weak detonation. Supported by FA8651-10-1-0004 (AFRL/RW) and N000014-12-1-0555 (ONR).

  15. REVIEW ARTICLE: Multi-component force balances for conventional and cryogenic wind tunnels

    NASA Astrophysics Data System (ADS)

    Ewald, Bernd F. R.

    2000-06-01

    The measurement of the total forces acting on the surface of a wind tunnel model is still the most important wind tunnel measurement technology. Either the model is mounted by struts to a balance, which is located outside the test section (an `external balance'), or the balance is located inside the model and connects the model structure to the mounting sting, which in the case of aeroplane configurations protrudes from the rear fuselage (an `internal balance'). This review concerns internal balances only. The functional principle is described and some comments on the demand for high accuracy are given. The optimization of designs for strain gauge balances, the fabrication methods and the selection of materials are commented on. The calibration theory of multi-component balances is outlined and the calibration equipment is described. Examples for conventional manual calibration equipment and for an automatic calibration machine are given. Finally the specific design features of cryogenic balances and half model balances are given. This review presents the author's experiences and developments. Since there is hardly any general literature on the subject of strain gauge balances and since the balance engineers in the world have not that much contact with each other, there may be different points of view at other institutions.

  16. Ensemble Averaged Conservation Equations for Multiphase, Multi-component, and Multi-material Flows

    SciTech Connect

    Ray A. Berry

    2003-08-01

    Many important “fluid” flows involve a combination of two or more materials having different properties. The multiple phases or components often exhibit relative motion among the phases or material classes. The microscopic motions of the individual constituents are complex and the solution to the micro-level evolutionary equations is difficult. Characteristic of such flows of multi-component materials is an uncertainty in the exact locations of the particular constituents at any particular time. For most practical purposes, it is not possible to exactly predict or measure the evolution of the details of such systems, nor is it even necessary or desirable. Instead, we are usually interested in more gross features of the motion, or the “average” behavior of the system. Here we present descriptive equations that will predict the evolution of this averaged behavior. Due to the complexities of interfaces and resultant discontinuities in fluid properties, as well as from physical scaling issues, it is essential to work with averaged quantities and parameters. We begin by tightening up, or more rigorously defining, our concept of an average. There are several types of averaging. The published literature predominantly contains two types of averaging: volume averaging [Whitaker 1999, Dobran 1991] and time averaging [Ishii 1975]. Occasionally combinations of the two are used. However, we utilize a more general approach by adopting what is known as ensemble averaging.

  17. Implementation evaluation of the Blueprint multi-component drug prevention programme: fidelity of school component delivery.

    PubMed

    Stead, Martine; Stradling, Robert; MacNeil, Morag; MacKintosh, Anne Marie; Minty, Sarah

    2007-11-01

    In order to achieve their desired aims, evidence-based, theory-driven drug education programmes need to be implemented as intended. Measurement of 'fidelity of implementation' is now included increasingly as part of programme evaluation, although measures and methods are sometimes limited. A more sophisticated approach to assessing implementation fidelity, based on Dane & Schneider's (1998) five dimensions, was used to examine the classroom curriculum element of the Blueprint programme. Blueprint was the largest and most rigorous evaluation of a multi-component drug prevention programme to date in the United Kingdom. Lessons were, overall, delivered with reasonable fidelity, although teachers did not always understand the thinking behind particular activities, suggesting that training needs to focus not only on content and methods but why particular approaches are important. Different dimensions of fidelity could conflict with one another: under pressure of time, generic elements and processes designed to reflect on learning were sometimes sacrificed in order that core drug education activities could be completed. Future drug education curricula need to build in more flexibility for discussion without compromising core evidence-based elements. Even with substantial training and support, individual variations in delivery were found, although few differences were found between teachers with prior expertise and teachers new to drug education. The methods and measures applied in the Blueprint study all represent attempts to improve on previous measures in terms of both reliability and sensitivity. In this respect the Blueprint study represents a valuable contribution to the science of implementation fidelity. PMID:17943526

  18. EXAFS Phase Retrieval Solution Tracking for Complex Multi-Component System: Synthesized Topological Inverse Computation

    NASA Astrophysics Data System (ADS)

    Lee, Jay Min; Yang, Dong-Seok; Bunker, Grant B.

    2013-04-01

    Using the FEFF kernel A(k,r), we describe the inverse computation from χ(k)-data to g(r)-solution in terms of a singularity regularization method based on complete Bayesian statistics process. In this work, we topologically decompose the system-matched invariant projection operators into two distinct types, (A+AA+A) and (AA+AA+), and achieved Synthesized Topological Inversion Computation (STIC), by employing a 12-operator-closed-loop emulator of the symplectic transformation. This leads to a numerically self-consistent solution as the optimal near-singular regularization parameters are sought, dramatically suppressing instability problems connected with finite precision arithmetic in ill-posed systems. By statistically correlating a pair of measured data, it was feasible to compute an optimal EXAFS phase retrieval solution expressed in terms of the complex-valued χ(k), and this approach was successfully used to determine the optimal g(r) for a complex multi-component system.

  19. Furnace Cyclic Oxidation Behavior of Multi-Component Low Conductivity Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Nesbitt, James A.; Barrett, Charles A.; McCue, Terry R.; Miller, Robert A.

    2004-01-01

    Ceramic thermal barrier coatings will play an increasingly important role in advanced gas turbine engines because of their ability to further increase engine operating temperatures and reduce cooling, thus helping achieve future engine low emission, high efficiency and improved reliability goals. Advanced multi-component zirconia-based thermal barrier coatings are being developed using an oxide defect clustering design approach to achieve the required coating low thermal conductivity and high temperature stability. Although the new composition coatings were not yet optimized for cyclic durability, an initial durability screening of the candidate coating materials was conducted using conventional furnace cyclic oxidation tests. In this paper, furnace cyclic oxidation behavior of plasma-sprayed zirconia-based defect cluster thermal barrier coatings was investigated at 1163 C using 45 min hot cycles. The ceramic coating failure mechanisms were studied using scanning electron microscopy (SEM) combined with X-ray diffraction (XRD) phase analysis after the furnace tests. The coating cyclic lifetime is also discussed in relation to coating processing, phase structures, dopant concentration, and other thermo-physical properties.

  20. A Multi-Component Social Skills Intervention for Children with Asperger Syndrome: The Junior Detective Training Program

    ERIC Educational Resources Information Center

    Beaumont, Renae; Sofronoff, Kate

    2008-01-01

    Background: The study aimed to investigate the effectiveness of a new multi-component social skills intervention for children with Asperger syndrome (AS): The Junior Detective Training Program. This 7-week program included a computer game, small group sessions, parent training sessions and teacher handouts. Method: Forty-nine children with AS were…

  1. Effect of SUS316L stainless steel surface conditions on the wetting of molten multi-component oxides ceramic

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Matsuda, Nozomu; Shinozaki, Nobuya; Miyoshi, Noriko; Shiraishi, Takanobu

    2015-02-01

    A study on the effect of SUS316L stainless steel surface conditions on the wetting behavior of molten multi-component oxides ceramic was performed and aimed to contribute to the further understanding of the application of oxides ceramic in penetration treatment of stainless steel coatings and the deposition of stainless steel cermet coatings. The results show that at 1273 K, different surface pre-treatments (polishing and heating) had an important effect on the wetting behavior. The molten multi-component oxides showed good wettability on both stainless steel substrates, however, the wetting process on the polished substrate was significantly slower than that on the heated substrates. The mechanism of the interfacial reactions was discussed based on the microscopic and thermodynamic analysis, the substrates reacted with oxygen generated from the decomposition of the molten multi-component oxides and oxygen contained in the argon atmosphere, and the oxide film caused the molten multi-component oxides ceramic to spread on the substrates surfaces. For the polished substrate, more time was required for the surface oxidation to reach the surface composition of Heated-S, which resulted in relatively slow spreading and wetting rates. Moreover, the variance of the surface roughness drove the final contact angles to slightly different values following the sequence Polished-S > Heated-S.

  2. Continuous Video Modeling to Prompt Completion of Multi-Component Tasks by Adults with Moderate Intellectual Disability

    ERIC Educational Resources Information Center

    Mechling, Linda C.; Ayres, Kevin M.; Purrazzella, Kaitlin; Purrazzella, Kimberly

    2014-01-01

    This investigation examined the ability of four adults with moderate intellectual disability to complete multi-component tasks using continuous video modeling. Continuous video modeling, which is a newly researched application of video modeling, presents video in a "looping" format which automatically repeats playing of the video while…

  3. Selective preparation of elusive and alternative single component polymorphic solid forms through multi-component crystallisation routes.

    PubMed

    Thomas, Lynne H; Wales, Craig; Wilson, Chick C

    2016-05-31

    A transferable, simple, method for producing previously elusive and novel polymorphic forms of important active pharmaceutical ingredients (APIs; paracetamol (acetaminophen), piroxicam and piracetam) is demonstrated. Nitrogen heterocyclic co-molecules are employed to influence the self-assembly crystallisation process in a multi-component environment. Previously unknown solvates have also been synthesised by this method. PMID:27079688

  4. An Integrated Multi-component Processing and Interpretation Framework for 3D Borehole Seismic Data

    SciTech Connect

    M. Karrenbach

    2004-10-15

    This report covers the April 2004-September 2004 time period. Work has been performed successfully on several tasks 1 through 16. Part of this work has been reported in 15418R03. Most of portions of these tasks have been executed independently. We progressed steadily and completed some of the sub-tasks, while others are still on going. We achieved the goals that we had set up in the task schedule. Reviewing the results of this work period indicates that our plan is solid and we did not encounter any unforeseen problems. The work plan will continue as scheduled. A midyear review will be presented in November or December 2004. Several independent tasks pursuant the statement of project objectives have been executed simultaneously and are still on-going. Use of real seismic test data is augmented by the creation a 3D ray tracing synthetic test data. We used the previously constructed 3D layered model and simulated data acquisition from a set of circular source locations at the surface of the model, while a close to vertical VSP well was used to capture the wave field data. The source pattern was optimized with respect to Fresnel zone width at the target depth. Multi-component particle displacements were recorded every 50 ft down with an array length of 4,000 ft. P-P as well as P-S reflections were specified in the resulting wave field. We ensured a large enough aperture with enough fine sampling to perform advanced processing, imaging and analysis tests in the future during this project. We constantly improved the interfacing of our software libraries with newly designed 3C display classes and mechanisms. We used the previously implemented 3C Work Bench tool as the primary prototyping tool. This work bench allows to load as well as manipulate and display data items in a flexible manner. We continued to demonstrate its basic functionality by loading source maps, horizons, seismic and velocity volumes, well logs into the tool, performing basic QC steps as is necessary

  5. Design and synthesis of single-source molecular precursors to homogeneous multi-component oxide materials

    NASA Astrophysics Data System (ADS)

    Fujdala, Kyle Lee

    This dissertation describes the syntheses of single-source molecular precursors to multi-component oxide materials. These molecules possess a core metal or element with various combinations of -OSi(O tBu)3, -O2P(OtBu) 2, and -OB[OSi(OtBu)3] 2 ligands. Such molecules decompose under mild thermolytic conditions (<200°C) to provide homogeneous carbon-free materials via the elimination of isobutylene and water. A gel is formed when thermolyses are performed in non-polar solvents, and subsequent drying of the gel in a conventional manner yields high surface area xerogels. This thermolytic molecular precursor (TMP) approach has been utilized to provide a variety of oxide materials with tailored properties. In addition, the oxygen rich environment of the molecular precursors coupled with the presence of M-O-E heterolinkages permits use of them as models for oxide-supported metal species and multi-component oxides. Significantly, the first complexes to contain three or more heteroelements suitable for use in the TMP method have been synthesized. Compounds for use as single-source molecular precursors have been synthesized containing Al, B, Cr, Hf, Mo, V, W, and Zr, and their thermal transformations have been examined. Heterogeneous catalytic reactions have been examined for selected materials. Also, cothermolyses of molecular precursors and additional molecules (i.e., metal alkoxides) have been utilized to provide materials with several components for potential use as catalysts or catalyst supports. Reactions of one and two equivs of HOSi(OtBu) 3 with Cr(OtBu)4 afforded the first Cr(IV) alkoxysiloxy complexes (tBuO) 3CrOSi(OtBu)3 and ( tBuO)2Cr[OSi(OtBu) 3]2, respectively. The high-yielding, convenient synthesis of (tBuO)3CrOSi(O tBu)3 make this complex a useful single-source molecular precursor, via the TMP method, to Cr/Si/O materials. The thermal transformations of (tBuO)3CrOSi(O tBu)3 and (tBuO) 2Cr[OSi(OtBu)3]2 to chromia-silica materials occurr at low temperatures

  6. Three-dimensional model for multi-component reactive transport with variable density groundwater flow

    USGS Publications Warehouse

    Mao, X.; Prommer, H.; Barry, D.A.; Langevin, C.D.; Panteleit, B.; Li, L.

    2006-01-01

    PHWAT is a new model that couples a geochemical reaction model (PHREEQC-2) with a density-dependent groundwater flow and solute transport model (SEAWAT) using the split-operator approach. PHWAT was developed to simulate multi-component reactive transport in variable density groundwater flow. Fluid density in PHWAT depends not on only the concentration of a single species as in SEAWAT, but also the concentrations of other dissolved chemicals that can be subject to reactive processes. Simulation results of PHWAT and PHREEQC-2 were compared in their predictions of effluent concentration from a column experiment. Both models produced identical results, showing that PHWAT has correctly coupled the sub-packages. PHWAT was then applied to the simulation of a tank experiment in which seawater intrusion was accompanied by cation exchange. The density dependence of the intrusion and the snow-plough effect in the breakthrough curves were reflected in the model simulations, which were in good agreement with the measured breakthrough data. Comparison simulations that, in turn, excluded density effects and reactions allowed us to quantify the marked effect of ignoring these processes. Next, we explored numerical issues involved in the practical application of PHWAT using the example of a dense plume flowing into a tank containing fresh water. It was shown that PHWAT could model physically unstable flow and that numerical instabilities were suppressed. Physical instability developed in the model in accordance with the increase of the modified Rayleigh number for density-dependent flow, in agreement with previous research. ?? 2004 Elsevier Ltd. All rights reserved.

  7. Unmixing Multi-Component Magnetic Mixtures in Geologic Materials Using First Order Reversal Curve Diagrams

    NASA Astrophysics Data System (ADS)

    Lascu, I.; Harrison, R. J.; Li, Y.; Muraszko, J.; Channell, J. E. T.; Piotrowski, A. M.; Hodell, D. A.; Necula, C.; Panaiotu, C. G.

    2015-12-01

    We have developed a magnetic unmixing method based on principal component analysis (PCA) of first-order reversal curve (FORC) diagrams. PCA provides an objective and robust statistical framework for unmixing, because it represents data variability as a linear combination of a limited number of principal components that are derived purely on the basis of natural variations contained within the dataset. For PCA we have resampled FORC distributions on grids that capture diagnostic signatures of magnetic domain states. Individual FORC diagrams were then recast as linear combinations of end-member (EM) FORC diagrams, located at user-defined positions in PCA space. The EM selection is guided by constraints derived from physical modeling, and is imposed by data scatter. To test our model, we have investigated temporal variations of two EMs in bulk North Atlantic sediment cores collected from the Rockall Trough and the Iberian Continental Margin. Sediments from these sites contain a mixture of magnetosomes and granulometrically distinct detrital magnetite. We have also quantified the spatial variation of three EM components in surficial sediments along the flow path of the North Atlantic Deep Water (NADW). These samples were separated into granulometric fractions, which also assisted in constraining EM definition. The unmixing model reveals systematic variations in EM relative abundance as a function of distance along NADW flow. Finally, we have applied PCA to the combined dataset of Rockall Trough and NADW sediments, which can be recast as a four-EM mixture, providing enhanced discrimination between components. Our method forms the foundation of a general solution to the problem of unmixing multi-component magnetic mixtures, a fundamental task of rock magnetic studies.

  8. Imaging the Yellowstone Magmatic System Using Multi-Component Ambient Noise Cross-Correlation and Tomography

    NASA Astrophysics Data System (ADS)

    Farrell, J.; Lin, F. C.

    2015-12-01

    We present a new S-wave velocity model for the Yellowstone magmatic system derived from the inversion of Rayleigh- and Love-wave phase velocity measurements from periods from 6 to 35 s. All available data from 2007-2014 within and near the Yellowstone region was downloaded for the USArray TA network (TA), the Yellowstone Seismic Network (WY), the NOISY array (Z2), the USGS Intermountain West network (IW), the Plate Boundary Observatory Borehole Seismic Network (PB), and the USGS National Seismic Network (US). For each station, we perform daily noise pre-processing (temporal normalization and spectrum whitening) simultaneously for all three components before multi-component noise cross-correlations are calculated. Results for both Rayleigh- and Love-wave phase velocity inversions clearly show the low velocity anomaly associated with the upper-crustal magma reservoir seen previously using body wave tomography. In addition, low-velocity anomalies associated with sediment-filled basins are visible in Wyoming. Short period low Love-wave velocities are seen along the Snake River Plain, the track of the Yellowstone hotspot likely related to the shallow sediment layer. Based on the surface wave phase velocity maps, we invert for a 3D S-wave crustal model. The resulting model will be compared to previous, but spatially limited, body wave S-wave models as well as recent body wave P-wave velocity models to better constrain Vp/Vs ratios as well as the melt fraction of the magma chamber. Preliminary results using amplitude information of noise cross-correlations to calculate Rayleigh-wave ellipticity, or Rayleigh-wave H/V (horizontal to vertical) amplitude ratios to better constrain the shallow velocity structure will also be discussed.

  9. CHANDRA REVEALS VARIABLE MULTI-COMPONENT X-RAY EMISSION FROM FU ORIONIS

    SciTech Connect

    Skinner, Stephen L.; Guedel, Manuel; Briggs, Kevin R.; Lamzin, Sergei A.

    2010-10-20

    FU Orionis is the prototype of a class of eruptive young stars ('FUors') characterized by strong optical outbursts. We recently completed an exploratory survey of FUors using XMM-Newton to determine their X-ray properties, about which little was previously known. The prototype FU Ori and V1735 Cyg were detected. The X-ray spectrum of FU Ori was found to be unusual, consisting of a cool moderately absorbed component plus a hotter component viewed through an absorption column density that is an order of magnitude higher. We present here a sensitive (99 ks) follow-up X-ray observation of FU Ori obtained at higher angular resolution with Chandra ACIS-S. The unusual multi-component spectrum is confirmed. The hot component is centered on FU Ori and dominates the emission above 2 keV. It is variable (a signature of magnetic activity) and is probably coronal emission originating close to FU Ori's surface viewed through cool gas in FU Ori's strong wind or accretion stream. In contrast, the X-ray centroid of the soft emission below 2 keV is offset 0.''20 to the southeast of FU Ori, toward the near-IR companion (FU Ori S). This offset amounts to slightly less than half the separation between the two stars. The most likely explanation for the offset is that the companion contributes significantly to the softer X-ray emission below 2 keV (and weakly above 2 keV). The superimposed X-ray contributions from FU Ori and the companion resolve the paradox posed by XMM-Newton of an apparently single X-ray source viewed through two different absorption columns.

  10. Vaporization modeling of petroleum-biofuel drops using a hybrid multi-component approach

    SciTech Connect

    Zhang, Lei; Kong, Song-Charng

    2010-11-15

    Numerical modeling of the vaporization characteristics of multi-component fuel mixtures is performed in this study. The fuel mixtures studied include those of binary components, biodiesel, diesel-biodiesel, and gasoline-ethanol. The use of biofuels has become increasingly important for reasons of environmental sustainability. Biofuels are often blended with petroleum fuels, and the detailed understanding of the vaporization process is essential to designing a clean and efficient combustion system. In this study, a hybrid vaporization model is developed that uses continuous thermodynamics to describe petroleum fuels and discrete components to represent biofuels. The model is validated using the experimental data of n-heptane, n-heptane-n-decane mixture, and biodiesel. Since biodiesel properties are not universal due to the variation in feedstock, methods for predicting biodiesel properties based on the five dominant fatty acid components are introduced. Good levels of agreement in the predicted and measured drop size histories are obtained. Furthermore, in modeling the diesel-biodiesel drop, results show that the drop lifetime increases with the biodiesel concentration in the blend. During vaporization, only the lighter components of diesel fuel vaporize at the beginning. Biodiesel components do not vaporize until some time during the vaporization process. On the other hand, results of gasoline-ethanol drops indicate that both fuels start to vaporize once the process begins. At the beginning, the lighter components of gasoline have a slightly higher vaporization rate than ethanol. After a certain time, ethanol vaporizes faster than the remaining gasoline components. At the end, the drop reduces to a regular gasoline drop with heavier components. Overall, the drop lifetime increases as the concentration of ethanol increases in the drop due to the higher latent heat. (author)

  11. GWELL,GWNACL,HOLA. Multi-Component, Multi-Feedzone Geothermal Wellbore Simulators

    SciTech Connect

    Aunzo, Z.P.; Bjornsson, G.; Bodvarsson, G.S.

    1991-10-10

    The simulators are designed to reproduce the measured flowing temperature and pressure profiles in flowing geothermal wells, and determine the relative contribution, fluid properties (e.g. enthalpy, temperature) and fluid chemical composition (e.g. CO2, NaCl) of each feedzone. Each simulator is designed to handle a specific problem: HOLA, GWNACL, and GWELL simulate `pure` water, presence of dissolved solids and presence of non condensable gases respectively. The codes can model multiple feedzones and heat loss to the formation.

  12. Toxic gases.

    PubMed Central

    Matthews, G.

    1989-01-01

    An overview of the widespread use of gases and some volatile solvents in modern society is given. The usual circumstances in which undue exposure may occur are described. The most prominent symptoms and general principles of diagnosis and treatment are given and are followed by more specific information on the commoner, more toxic materials. While acute poisonings constitute the greater part of the paper, some indication of chronic disorders arising from repeated or prolonged exposure is also given. PMID:2687827

  13. Noble Gases

    NASA Astrophysics Data System (ADS)

    Podosek, F. A.

    2003-12-01

    The noble gases are the group of elements - helium, neon, argon, krypton, xenon - in the rightmost column of the periodic table of the elements, those which have "filled" outermost shells of electrons (two for helium, eight for the others). This configuration of electrons results in a neutral atom that has relatively low electron affinity and relatively high ionization energy. In consequence, in most natural circumstances these elements do not form chemical compounds, whence they are called "noble." Similarly, much more so than other elements in most circumstances, they partition strongly into a gas phase (as monatomic gas), so that they are called the "noble gases" (also, "inert gases"). (It should be noted, of course, that there is a sixth noble gas, radon, but all isotopes of radon are radioactive, with maximum half-life a few days, so that radon occurs in nature only because of recent production in the U-Th decay chains. The factors that govern the distribution of radon isotopes are thus quite different from those for the five gases cited. There are interesting stories about radon, but they are very different from those about the first five noble gases, and are thus outside the scope of this chapter.)In the nuclear fires in which the elements are forged, the creation and destruction of a given nuclear species depends on its nuclear properties, not on whether it will have a filled outermost shell when things cool off and nuclei begin to gather electrons. The numerology of nuclear physics is different from that of chemistry, so that in the cosmos at large there is nothing systematically special about the abundances of the noble gases as compared to other elements. We live in a very nonrepresentative part of the cosmos, however. As is discussed elsewhere in this volume, the outstanding generalization about the geo-/cosmochemistry of the terrestrial planets is that at some point thermodynamic conditions dictated phase separation of solids from gases, and that the

  14. NuSTAR Spectroscopy of Multi-component X-Ray Reflection from NGC 1068

    NASA Astrophysics Data System (ADS)

    Bauer, Franz E.; Arévalo, Patricia; Walton, Dominic J.; Koss, Michael J.; Puccetti, Simonetta; Gandhi, Poshak; Stern, Daniel; Alexander, David M.; Baloković, Mislav; Boggs, Steve E.; Brandt, William N.; Brightman, Murray; Christensen, Finn E.; Comastri, Andrea; Craig, William W.; Del Moro, Agnese; Hailey, Charles J.; Harrison, Fiona A.; Hickox, Ryan; Luo, Bin; Markwardt, Craig B.; Marinucci, Andrea; Matt, Giorgio; Rigby, Jane R.; Rivers, Elizabeth; Saez, Cristian; Treister, Ezequiel; Urry, C. Megan; Zhang, William W.

    2015-10-01

    We report on high-energy X-ray observations of the Compton-thick Seyfert 2 galaxy NGC 1068 with NuSTAR, which provide the best constraints to date on its >10 keV spectral shape. The NuSTAR data are consistent with those from past and current instruments to within cross-calibration uncertainties, and we find no strong continuum or line variability over the past two decades, which is in line with its X-ray classification as a reflection-dominated Compton-thick active galactic nucleus. The combined NuSTAR, Chandra, XMM-Newton, and Swift BAT spectral data set offers new insights into the complex secondary emission seen instead of the completely obscured transmitted nuclear continuum. The critical combination of the high signal-to-noise NuSTAR data and the decomposition of the nuclear and extranuclear emission with Chandra allow us to break several model degeneracies and greatly aid physical interpretation. When modeled as a monolithic (i.e., a single NH) reflector, none of the common Compton reflection models are able to match the neutral fluorescence lines and broad spectral shape of the Compton reflection hump without requiring unrealistic physical parameters (e.g., large Fe overabundances, inconsistent viewing angles, or poor fits to the spatially resolved spectra). A multi-component reflector with three distinct column densities (e.g., with best-fit values of NH of 1.4 × 1023, 5.0 × 1024, and 1025 cm-2) provides a more reasonable fit to the spectral lines and Compton hump, with near-solar Fe abundances. In this model, the higher NH component provides the bulk of the flux to the Compton hump, while the lower NH component produces much of the line emission, effectively decoupling two key features of Compton reflection. We find that ≈30% of the neutral Fe Kα line flux arises from >2″ (≈140 pc) and is clearly extended, implying that a significant fraction (and perhaps most) of the <10 keV reflected component arises from regions well outside a parsec

  15. Affinity ligands for glycoprotein purification based on the multi-component Ugi reaction.

    PubMed

    Chen, Chen; Khoury, Graziella El; Lowe, Christopher R

    2014-10-15

    One challenge facing the purification of therapeutic glycoproteins by affinity chromatography is creating ligands specific for the glycan moiety. Affinity chromatography of glycoproteins is currently conducted with immobilized lectins or boronates, although biomimetic ligands could present a more desirable option. This work describes the rational design and combinatorial synthesis of carbohydrate-binding ligands based on the solid phase multi-component Ugi reaction. An aldehyde-functionalized Sepharose™ solid support constitutes one component (aldehyde) in the four-component reaction, while the other three components (a primary/secondary amine, a carboxylic acid and an isocyanide) are varied in a combinatorial fashion to generate a tri-substituted Ugi scaffold which provides a degree of rigidity and is functionally suitable for interacting with the glycan moiety of glycoproteins. An Ugi library containing 48 ligands was initially screened against glucose oxidase (GOx) as the model glycoprotein to identify a candidate ligand, A13C24I8, which showed affinity to GOx through its carbohydrate moiety. Immobilized ligand A13C24I8 demonstrated a static binding capacity of 16.7mg GOx/ml resin and an apparent dissociation constant (Kd) of 1.45×10(-6)M at pH 7.4. The adsorbent can also bind 8.1mg AGP/ml resin and displays an apparent affinity constant Kd=1.44×10(-5)M. The ligand has a sugar specificity in the following sequence: sorbitol>fructose>mannitol>ribose>arabinose>xylose>galactose>mannose>glucose>fructose; however, it did not display any specificity for sialic acid or methyl α-D-glycosides. A control ligand, generated by substitution of C24 (3-carboxyphenylboronic acid) with C7 (4-hydroxyphenyl acetic acid), failed to show affinity to the carbohydrate moiety, supporting the importance of the role that boronic acid group plays in sugar binding. GOx spiked E. coli samples were loaded onto immobilized ligand A13C24I8, 3-aminophenylboronic acid (APBA) and

  16. Iterative development of Stand Up Australia: a multi-component intervention to reduce workplace sitting

    PubMed Central

    2014-01-01

    Background Sitting, particularly in prolonged, unbroken bouts, is widespread within the office workplace, yet few interventions have addressed this newly-identified health risk behaviour. This paper describes the iterative development process and resulting intervention procedures for the Stand Up Australia research program focusing on a multi-component workplace intervention to reduce sitting time. Methods The development of Stand Up Australia followed three phases. 1) Conceptualisation: Stand Up Australia was based on social cognitive theory and social ecological model components. These were operationalised via a taxonomy of intervention strategies and designed to target multiple levels of influence including: organisational structures (e.g. via management consultation), the physical work environment (via provision of height-adjustable workstations), and individual employees (e.g. via face-to-face coaching). 2) Formative research: Intervention components were separately tested for their feasibility and acceptability. 3) Pilot studies: Stand Up Comcare tested the integrated intervention elements in a controlled pilot study examining efficacy, feasibility and acceptability. Stand Up UQ examined the additional value of the organisational- and individual-level components over height-adjustable workstations only in a three-arm controlled trial. In both pilot studies, office workers’ sitting time was measured objectively using activPAL3 devices and the intervention was refined based on qualitative feedback from managers and employees. Results Results and feedback from participants and managers involved in the intervention development phases suggest high efficacy, acceptance, and feasibility of all intervention components. The final version of the Stand Up Australia intervention includes strategies at the organisational (senior management consultation, representatives consultation workshop, team champions, staff information and brainstorming session with information

  17. Numerical Investigation of Thermal Distribution and Pressurization Behavior in Helium Pressurized Cryogenic Tank by Introducing a Multi-component Model

    NASA Astrophysics Data System (ADS)

    Lei, Wang; Yanzhong, Li; Zhan, Liu; Kang, Zhu

    An improved CFD model involving a multi-component gas mixturein the ullage is constructed to predict the pressurization behavior of a cryogenic tank considering the existence of pressurizing helium.A temperature difference between the local fluid and its saturation temperature corresponding to the vapor partial pressure is taken as the phase change driving force. As practical application of the model, hydrogen and oxygen tanks with helium pressurization arenumerically simulated by using themulti-component gas model. The results presentthat the improved model produce higher ullage temperature and pressure and lower wall temperaturethan those without multi-component consideration. The phase change has a slight influence on thepressurization performance due to the small quantities involved.

  18. A multi-component domino reaction for the direct access to polyfunctionalized indoles via intermolecular allylic esterification and indolation†

    PubMed Central

    Jiang, Bo; Yi, Mian-Shuai; Shi, Feng; Pindi, Suresh; McDowell, Patrick

    2013-01-01

    A novel multi-component reaction for the synthesis of polyfunctionalized indoles and bis-indoles has been established. The reaction pathways were controlled by varying enamines with different substitution patterns to give polyfunctionalized indoles and bis-indoles selectively. The reaction proceeds at a fast speed within 15–30 min with water as the major byproduct, which makes work-up convenient. PMID:22038299

  19. First principles study on the electronic structures and stability of Cr 7C 3 type multi-component carbides

    NASA Astrophysics Data System (ADS)

    Xiao, B.; Feng, J.; Zhou, C. T.; Xing, J. D.; Xie, X. J.; Chen, Y. H.

    2008-06-01

    First principles calculations were conducted to investigate the stabilities of six multi-component carbides of Cr 7C 3 by calculating the cohesive energy and formation enthalpy of them. The theoretical predictions were compared with the experimental results and they were in agreement with each other. The electronic structures of the six carbides were also calculated in order to provide more information about the relationship between the stability and crystal compositions at atomic scale.

  20. Questioning the role of the frontopolar cortex in multi-component behavior – a TMS/EEG study

    PubMed Central

    Gohil, Krutika; Dippel, Gabriel; Beste, Christian

    2016-01-01

    Cognitive control is central to many every day situations. There, we usually have to combine different actions to achieve a task goal. Several lines of research indicated that areas in the prefrontal cortex determine cognitive control in situations requiring multi-component behavior. One of this is the frontopolar cortex (FPC). However, direct non-correlative evidence for this notion is widely lacking. In the current study we test the importance of the FPC for the implementation of action cascading processes in a TMS/EEG study. The data, however, clearly show that the FPC does not modulate behavioral or neurophysiological parameters reflecting action cascading, which is in contrast to the findings of dorsolateral prefrontal cortex. The results are supported by a Bayesian analysis of the data. The results suggest that a possible role of the FPC in multi-component behavior needs to be refined. At least in situations, where multi-component behavior is achieved by stopping and switching processes and does not impose high demands on working memory processes the FPC seems to play no role in the implementation of this major cognitive control function. PMID:26924655

  1. Envelope calculation of the multi-component signal and its application to the deterministic component cancellation in bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Ming, A. B.; Zhang, W.; Qin, Z. Y.; Chu, F. L.

    2015-01-01

    Commonly presented as cyclic impulse responses with some degrees of randomness, the vibrations induced by bearing faults are multi-component signals and usually overwhelmed by other deterministic components, which may degrade the efficiency of the traditional envelope analysis used for bearing fault feature extraction. In this paper, the envelope of the multi-component signal, including both discrete frequency components and cyclic impulse responses, is theoretically calculated by the Hilbert transform in both time and frequency domains at first. Then, a novel deterministic component cancellation method is proposed based on the iterative calculation of the signal envelope. Finally, simulations and experiments are used to validate the theoretical calculation and the proposed deterministic component cancellation method. It is indicated that the oscillation part of the envelope is dominated by the cross-terms of the multi-component signal, and that the cross-terms between a discrete frequency component and cyclic impulse responses present as new cyclic impulse responses, which retain the cyclic feature of the original ones. Furthermore, the deterministic component can be canceled by iteratively subtracting the direct current (DC) offset of the envelope. Compared with the cepstrum pre-whiten (CPW) method, used to separate the deterministic (discrete frequency) component from the random component (vibration induced by the bearing fault), the proposed method is more efficient to the shifting of the cyclic impulse responses from the powerful deterministic component with little disruption, and is more suitable for the real time signal processing owing to the high efficient calculation of the Hilbert transform.

  2. Zwanzig model of multi-component mixtures of biaxial particles: y3 theory re-visited

    NASA Astrophysics Data System (ADS)

    Sokolova, E. P.; Tumanyan, N. P.; Vlasov, A. Yu.; Masters, A. J.

    The paper considers the thermodynamic and phase ordering properties of a multi-component Zwanzig mixture of hard rectangular biaxial parallelepipeds. An equation of state (EOS) is derived based on an estimate of the number of arrangements of the particles on a three- dimensional cubic lattice. The methodology is a generalization of the Flory-DiMarzio counting scheme, but, unlike previous work, this treatment is thermodynamically consistent. The results are independent of the order in which particles are placed on the lattice. By taking the limit of zero lattice spacing, a translationally continuous variant of the model (the off-lattice variant) is obtained. The EOS is identical to that obtained previously by a wide variety of different approaches. In the off-lattice limit, it corresponds to a third-level y-expansion and, in the case of a binary mixture of square platelets, it also corresponds to the EOS obtained from fundamental measure theory. On the lattice it is identical to the EOS obtained by retaining only complete stars in the virial expansion. The off-lattice theory is used to study binary mixtures of rods (R1 - R2) and binary mixtures of platelets (P1 - P2). The particles were uniaxial, of length (thickness) L and width D. The aspect ratios Γi = Li/Di of the components were kept constant (Γ1R = 15, Γ1P = 1/15 and Γ2R = 150, Γ2P = 1/150), so the second virial coefficient of R1 was identical to P1 and similarly for R2 and P2. The volume ratio of particles 1 and 2, v1/v2, was then varied, with the constraints that viR = viP and ILM0001. Results on nematic-isotropic (N - I) phase coexistence at an infinite dilution of component 2, are qualitatively similar for rods and platelets. At small values of the ratio v1/v2, the addition of component 2 (i.e. a thin rod (e.g. a polymer) or a thin plate) results in the stabilization of the nematic phase. For larger values of v1/v2, however, this effect is reversed and the addition of component 2 destabilizes the

  3. System and method to determine thermophysical properties of a multi-component gas

    DOEpatents

    Morrow, Thomas B.; Behring, II, Kendricks A.

    2003-08-05

    A system and method to characterize natural gas hydrocarbons using a single inferential property, such as standard sound speed, when the concentrations of the diluent gases (e.g., carbon dioxide and nitrogen) are known. The system to determine a thermophysical property of a gas having a first plurality of components comprises a sound velocity measurement device, a concentration measurement device, and a processor to determine a thermophysical property as a function of a correlation between the thermophysical property, the speed of sound, and the concentration measurements, wherein the number of concentration measurements is less than the number of components in the gas. The method includes the steps of determining the speed of sound in the gas, determining a plurality of gas component concentrations in the gas, and determining the thermophysical property as a function of a correlation between the thermophysical property, the speed of sound, and the plurality of concentrations.

  4. Device For Determining Therophysical Properties Of A Multi-Component Gas At Arbitrary Temperature And Pressure

    DOEpatents

    Morrow, Thomas B.; Behring, II, Kendricks A.

    2005-02-01

    A computer product for determining thermodynamic properties of a natural gas hydrocarbon, when the speed of sound in the gas is known at an arbitrary temperature and pressure. Thus, the known parameters are the sound speed, temperature, pressure, and concentrations of any dilute components of the gas. The method uses a set of reference gases and their calculated density and speed of sound values to estimate the density of the subject gas. Additional calculations can be made to estimate the molecular weight of the subject gas, which can then be used as the basis for mass flow calculations, to determine the speed of sound at standard pressure and temperature, and to determine various thermophysical characteristics of the gas.

  5. From unitary to uniform Bose gases

    NASA Astrophysics Data System (ADS)

    Hadzibabic, Zoran

    2014-05-01

    In this talk I will give an overview of our recent experiments on Bose gases in extreme interaction regimes. In one limit, we studied the stability of a unitary Bose gas, with strongest possible interactions allowed by quantum mechanics. In the other limit, we studied purely quantum-statistical ideal-gas phenomena, such as the quantum Joule-Thomson effect, by achieving Bose-Einstein condensation in a quasi-uniform potential of an optical-box trap.

  6. Percolation segregation in multi-size and multi-component particulate mixtures: Measurement, sampling, and modeling

    NASA Astrophysics Data System (ADS)

    Jha, Anjani K.

    Particulate materials are routinely handled in large quantities by industries such as, agriculture, electronic, ceramic, chemical, cosmetic, fertilizer, food, nutraceutical, pharmaceutical, power, and powder metallurgy. These industries encounter segregation due to the difference in physical and mechanical properties of particulates. The general goal of this research was to study percolation segregation in multi-size and multi-component particulate mixtures, especially measurement, sampling, and modeling. A second generation primary segregation shear cell (PSSC-II), an industrial vibrator, a true cubical triaxial tester, and two samplers (triers) were used as primary test apparatuses for quantifying segregation and flowability; furthermore, to understand and propose strategies to mitigate segregation in particulates. Toward this end, percolation segregation in binary, ternary, and quaternary size mixtures for two particulate types: urea (spherical) and potash (angular) were studied. Three coarse size ranges 3,350-4,000 mum (mean size = 3,675 mum), 2,800-3,350 mum (3,075 mum), and 2,360-2,800 mum (2,580 mum) and three fines size ranges 2,000-2,360 mum (2,180 mum), 1,700-2,000 mum (1,850 mum), and 1,400-1,700 mum (1,550 mum) for angular-shaped and spherical-shaped were selected for tests. Since the fines size 1,550 mum of urea was not available in sufficient quantity; therefore, it was not included in tests. Percolation segregation in fertilizer bags was tested also at two vibration frequencies of 5 Hz and 7Hz. The segregation and flowability of binary mixtures of urea under three equilibrium relative humidities (40%, 50%, and 60%) were also tested. Furthermore, solid fertilizer sampling was performed to compare samples obtained from triers of opening widths 12.7 mm and 19.1 mm and to determine size segregation in blend fertilizers. Based on experimental results, the normalized segregation rate (NSR) of binary mixtures was dependent on size ratio, mixing ratio

  7. The Spitzer Survey of Stellar Structure in Galaxies (S4G): Multi-component Decomposition Strategies and Data Release

    NASA Astrophysics Data System (ADS)

    Salo, Heikki; Laurikainen, Eija; Laine, Jarkko; Comerón, Sebastien; Gadotti, Dimitri A.; Buta, Ron; Sheth, Kartik; Zaritsky, Dennis; Ho, Luis; Knapen, Johan; Athanassoula, E.; Bosma, Albert; Laine, Seppo; Cisternas, Mauricio; Kim, Taehyun; Muñoz-Mateos, Juan Carlos; Regan, Michael; Hinz, Joannah L.; Gil de Paz, Armando; Menendez-Delmestre, Karin; Mizusawa, Trisha; Erroz-Ferrer, Santiago; Meidt, Sharon E.; Querejeta, Miguel

    2015-07-01

    The Spitzer Survey of Stellar Structure in Galaxies (S4G) is a deep 3.6 and 4.5 μm imaging survey of 2352 nearby (<40 Mpc) galaxies. We describe the S4G data analysis pipeline 4, which is dedicated to two-dimensional structural surface brightness decompositions of 3.6 μm images, using GALFIT3.0. Besides automatic 1-component Sérsic fits, and 2-component Sérsic bulge + exponential disk fits, we present human-supervised multi-component decompositions, which include, when judged appropriate, a central point source, bulge, disk, and bar components. Comparison of the fitted parameters indicates that multi-component models are needed to obtain reliable estimates for the bulge Sérsic index and bulge-to-total light ratio (B/T), confirming earlier results. Here, we describe the preparations of input data done for decompositions, give examples of our decomposition strategy, and describe the data products released via IRSA and via our web page (www.oulu.fi/astronomy/S4G_PIPELINE4/MAIN). These products include all the input data and decomposition files in electronic form, making it easy to extend the decompositions to suit specific science purposes. We also provide our IDL-based visualization tools (GALFIDL) developed for displaying/running GALFIT-decompositions, as well as our mask editing procedure (MASK_EDIT) used in data preparation. A detailed analysis of the bulge, disk, and bar parameters derived from multi-component decompositions will be published separately.

  8. Synthesis of Lithium Boracarbonate Ion Pairs by Copper-Catalyzed Multi-Component Coupling of Carbon Dioxide, Diboron, and Aldehydes.

    PubMed

    Carry, Béatrice; Zhang, Liang; Nishiura, Masayoshi; Hou, Zhaomin

    2016-05-17

    The catalytic selective multi-component coupling of CO2 , bis(pinacolato)diboron, LiOtBu, and a wide range of aldehydes has been achieved for the first time by using an NHC-copper catalyst. This transformation has efficiently afforded a series of novel lithium cyclic boracarbonate ion pair compounds in high yields from readily available starting materials. This protocol has not only provided a new catalytic process for the utilization of CO2 , but it has also constituted a novel route for the efficient synthesis of a new class of lithium borate compounds that might be of interest as potential electrolyte candidates for lithium ion batteries. PMID:27061244

  9. A multi-component fiber-reinforced PHEMA-based hydrogel/HAPEX™ device for customized intervertebral disc prosthesis.

    PubMed

    Gloria, Antonio; De Santis, Roberto; Ambrosio, Luigi; Causa, Filippo; Tanner, K Elizabeth

    2011-05-01

    Spinal disease due to intervertebral disc degeneration represents a serious medical problem which affects many people worldwide. Disc arthroplasty may be considered the future ''gold standard'' of back pain treatment, even if problems related to available disc prostheses are considered. Hence, the aim of the present study was to improve the artificial disc technology by proposing the engineering of a pilot-scale device production process for a total multi-component intervertebral disc prosthesis. The device is made up of a poly(2-hydroxyethyl methacrylate)/poly(methyl methacrylate) (PHEMA/PMMA) (80/20 w/w) semi-interpenetrating polymer network (s-IPN) composite hydrogel reinforced with poly(ethylene terephthalate) (PET) fibers as annulus/nucleus substitute, and two hydroxyapatite-reinforced polyethylene composite (HAPEX™) endplates in order to anchor the multi-component device to the vertebral bodies. Static and dynamic-mechanical characterization show appropriate mechanical behavior. An example of engineering of a suitable pilot-scale device production process is also proposed in order to manufacture custom made implants. PMID:20511384

  10. Plume expansion and stoichiometry in the growth of multi-component thin films using dual-laser ablation

    NASA Astrophysics Data System (ADS)

    Mukherjee, Pritish; Cuff, John B.; Witanachchi, Sarath

    1998-05-01

    The application of dual-laser ablation for the growth of ZnO and multi-component films of CuIn 0.75.Ga 0.25Se 2 is presented. Comparison of the optical emission from the ZnO plume under dual-laser and single excimer laser ablation reveals that the coupling of the CO 2 laser into the excimer laser-ablated plume causes both significant ionic excitation as well as lateral plume expansion. The cos 21( θ) thickness profile of the single laser film transforms to a more uniform cos 6( θ) for dual-laser ablation. A comparison of the enhancement of film uniformity at different CO 2 laser fluences shows that increasing the CO 2 laser energy leads to greater film uniformity in dual-laser ablation. The advantages of the growth of multi-component materials using dual-laser ablation are demonstrated by optical plume analysis and the deposition of CuIn 0.75Ga 0.25Se 2 films.

  11. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging–ion mass spectrometry

    PubMed Central

    Fanood, Mohammad M Rafiee; Ram, N. Bhargava; Lehmann, C. Stefan; Powis, Ivan; Janssen, Maurice H. M.

    2015-01-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron–ion coincidence imaging spectrometer. As proof of concept, vapours containing ∼1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2–4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument. PMID:26104140

  12. Online Nanoflow RP-RP-MS Reveals Dynamics of Multi-component Ku Complex in Response to DNA Damage

    PubMed Central

    Zhou, Feng; Cardoza, Job D.; Ficarro, Scott B.; Adelmant, Guillaume O.; Lazaro, Jean-Bernard; Marto, Jarrod A.

    2010-01-01

    Tandem affinity purification (TAP) coupled with mass spectrometry has become the technique of choice for characterization of multi-component protein complexes. While current TAP protocols routinely provide high yield and specificity for proteins expressed under physiologically relevant conditions, analytical figures of merit required for efficient and in-depth LC-MS analysis remain unresolved. Here we implement a multidimensional chromatography platform, based on two stages of reversed-phase separation operated at high and low pH, respectively. We compare performance metrics for RP-RP and SCX-RP for the analysis of complex peptide mixtures derived from cell lysate, as well as protein complexes purified via TAP. Our data reveal that RP-RP fractionation outperforms SCX-RP primarily due to increased peak capacity in the first dimension separation. We integrate this system with miniaturized LC assemblies to achieve true online fractionation at low (≤5nL/min) effluent flow rates. Stable isotope labeling is used to monitor the dynamics of the multi-component Ku protein complex in response to DNA damage induced by gamma radiation. PMID:20873769

  13. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging-ion mass spectrometry.

    PubMed

    Fanood, Mohammad M Rafiee; Ram, N Bhargava; Lehmann, C Stefan; Powis, Ivan; Janssen, Maurice H M

    2015-01-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron-ion coincidence imaging spectrometer. As proof of concept, vapours containing ∼1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2-4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument. PMID:26104140

  14. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging-ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Fanood, Mohammad M. Rafiee; Ram, N. Bhargava; Lehmann, C. Stefan; Powis, Ivan; Janssen, Maurice H. M.

    2015-06-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron-ion coincidence imaging spectrometer. As proof of concept, vapours containing ~1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2-4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument.

  15. Atom chips with two-dimensional electron gases: Theory of near-surface trapping and ultracold-atom microscopy of quantum electronic systems

    SciTech Connect

    Sinuco-Leon, G.; Kaczmarek, B.; Krueger, P.; Fromhold, T. M.

    2011-02-15

    We show that current in a two-dimensional electron gas (2DEG) can trap ultracold atoms <1 {mu}m away with orders of magnitude less spatial noise than a metal trapping wire. This enables the creation of hybrid systems, which integrate ultracold atoms with quantum electronic devices to give extreme sensitivity and control: For example, activating a single quantized conductance channel in the 2DEG can split a Bose-Einstein condensate (BEC) for atom interferometry. In turn, the BEC offers unique structural and functional imaging of quantum devices and transport in heterostructures and graphene.

  16. Rapid theory-guided prototyping of ductile Mg alloys: from binary to multi-component materials

    NASA Astrophysics Data System (ADS)

    Pei, Zongrui; Friák, Martin; Sandlöbes, Stefanie; Nazarov, Roman; Svendsen, Bob; Raabe, Dierk; Neugebauer, Jörg

    2015-09-01

    In order to identify a method allowing for a fast solute assessment without lengthy ab initio calculations, we analyze correlations and anti-correlation between the {{{I}}}1 stacking fault energies ({{{I}}}1SFEs), which were shown to be related to the macroscopic ductility in Mg alloys, and five material parameters of 18 different elemental solutes. Our analysis reveals that the atomic volume V of pure solutes, their electronegativity ν and bulk modulus B are either linearly or logarithmically related to the {{{I}}}1 SFE. Comparing the impact of solutes with that of yttrium (that increases the ductility in Mg) we propose a single numerical quantity (called yttrium similarity index, YSI) that is based on these inter-relations. Subsequently, we evaluate this new figure of merit for 76 elements from the periodic table of elements in search for solutes reducing the {{{I}}}1 SFE. Limiting ourselves first to binary Mg alloys, we hardly find any alternative solutes providing similar {{{I}}}1{SFE} reduction as that due to rare-earth (RE) additions. Therefore, we extended our search to ternary Mg alloys. Assuming that the physical properties of solute combinations can be represented by their average values, 2850 solute combinations were checked and 133 solute pairs (not including any RE elements) have been found to have a YSI larger than 0.85. Quantum-mechanical calculations have been subsequently performed for 11 solute pairs with YSIs higher than 0.95 and they were all found to reduce the {{{I}}}1{SFE} in excellent agreement with the predictions based on the YSI.

  17. Co-Fabrication: A Strategy for Building Multi-Component Microsystems

    PubMed Central

    Siegel, Adam C.; Tang, Sindy K. Y.; Nijhuis, Christian A.; Hashimoto, Michinao; Phillips, Scott T.; Dickey, Michael D.; Whitesides, George M.

    2010-01-01

    that provide function in channels in liquid phase—makes it possible to design and build microsystems with component materials that cannot be easily manipulated conventionally (such as solid materials with low melting points, liquid metals, liquid crystals, fused salts, foams, emulsions, gases, polymers, biomaterials, and fragile organics). Moreover, materials can be altered, removed, or replaced after the manufacturing stage. For example, co-fabrication allows one to build devices in which a liquid flows through the device during use (or is replaced before use). Metal wires can be melted and re-set by heating (in principle, repairing a break). This method leads to certain kinds of structures—such as integrated metallic wires with large cross-sectional areas, or optical waveguides aligned in the same plane as microfluidic channels—that would be difficult or impossible to make with techniques such as sputter deposition or evaporation. This Account outlines the strategy of co-fabrication, describing several co-fabricated microsystems that combine microfluidics with (i) electrical wires for microheaters, electromagnets, and organic electrodes; (ii) fluidic optical components, such as optical waveguides, lenses, and light sources; (iii) gels for biological cell cultures; and (iv) droplets for compartmentalized chemical reactions, such as protein crystallization. PMID:20088528

  18. FAST TRACK COMMUNICATION Multi-component generalizations of the CH equation: geometrical aspects, peakons and numerical examples

    NASA Astrophysics Data System (ADS)

    Holm, D. D.; Ivanov, R. I.

    2010-12-01

    The Lax pair formulation of the two-component Camassa-Holm equation (CH2) is generalized to produce an integrable multi-component family, CH(n, k), of equations with n components and 1 <= |k| <= n velocities. All of the members of the CH(n, k) family show fluid-dynamics properties with coherent solitons following particle characteristics. We determine their Lie-Poisson Hamiltonian structures and give numerical examples of their soliton solution behaviour. We concentrate on the CH(2, k) family with one or two velocities, including the CH(2, -1) equation in the Dym position of the CH2 hierarchy. A brief discussion of the CH(3, 1) system reveals the underlying graded Lie-algebraic structure of the Hamiltonian formulation for CH(n, k) when n >= 3. Fondly recalling our late friend Jerry Marsden.

  19. The effect of carbon nanotubes and graphene on the mechanical properties of multi-component polymeric composites

    NASA Astrophysics Data System (ADS)

    Dervishi, Enkeleda; Hategekimana, Festus; Boyer, Laurent; Watanabe, Fumiya; Mustafa, Thikra; Biswas, Abhijit; Biris, Alexandru R.; Biris, Alexandru S.

    2013-12-01

    Two types of nano-materials (nanotubes and graphene) were incorporated at different concentrations into a bio-compatible polymer matrix, and the mechanical properties of the composite films were studied. Although both nanomaterials improved the mechanical attributes of the polymer, it was found that the composites containing the nanotube-graphene mixture exhibited significantly superior elasto-plastic properties. This work presents a facile technique of fabricating nano-composites that could be scaled up and applied to various types of polymers. These multi-component films have the potential to be used in a wide range of applications including bio-medicine and photovoltaics, as well as the military and automotive industry.

  20. Evolution of multi-component anion relay chemistry (ARC): construction of architecturally complex natural and unnatural products.

    PubMed

    Smith, Amos B; Wuest, William M

    2008-12-01

    Efficient construction of architecturally complex natural and unnatural products is the hallmark of organic chemistry. Anion relay chemistry (ARC)-a multi-component coupling protocol-has the potential to provide the chemist with a powerful synthetic tactic, enabling efficient, rapid elaboration of structurally complex scaffolds in a single operation with precise stereochemical control. The ARC tactic can be subdivided into two main classes, comprising the relay of negative charge either through bonds or through space, the latter with aid of a transfer agent. This review will present the current state of through-space anion relay, in conjunction with examples of natural and unnatural product syntheses that illustrate the utility of this synthetic method. PMID:19030533

  1. Modeling complex and multi-component food systems in molecular dynamics simulations on the example of chocolate conching.

    PubMed

    Greiner, Maximilian; Sonnleitner, Bettina; Mailänder, Markus; Briesen, Heiko

    2014-02-01

    Additional benefits of foods are an increasing factor in the consumer's purchase. To produce foods with the properties the consumer demands, understanding the micro- and nanostructure is becoming more important in food research today. We present molecular dynamics (MD) simulations as a tool to study complex and multi-component food systems on the example of chocolate conching. The process of conching is chosen because of the interesting challenges it provides: the components (fats, emulsifiers and carbohydrates) contain diverse functional groups, are naturally fluctuating in their chemical composition, and have a high number of internal degrees of freedom. Further, slow diffusion in the non-aqueous medium is expected. All of these challenges are typical to food systems in general. Simulation results show the suitability of present force fields to correctly model the liquid and crystal density of cocoa butter and sucrose, respectively. Amphiphilic properties of emulsifiers are observed by micelle formation in water. For non-aqueous media, pulling simulations reveal high energy barriers for motion in the viscous cocoa butter. The work for detachment of an emulsifier from the sucrose crystal is calculated and matched with detachment of the head and tail groups separately. Hydrogen bonding is shown to be the dominant interaction between the emulsifier and the crystal surface. Thus, MD simulations are suited to model the interaction between the emulsifier and sugar crystal interface in non-aqueous media, revealing detailed information about the structuring and interactions on a molecular level. With interaction parameters being available for a wide variety of chemical groups, MD simulations are a valuable tool to understand complex and multi-component food systems in general. MD simulations provide a substantial benefit to researchers to verify their hypothesis in dynamic simulations with an atomistic resolution. Rapid rise of computational resources successively

  2. Multi-scale diffuse interface modeling of multi-component two-phase flow with partial miscibility

    NASA Astrophysics Data System (ADS)

    Kou, Jisheng; Sun, Shuyu

    2016-08-01

    In this paper, we introduce a diffuse interface model to simulate multi-component two-phase flow with partial miscibility based on a realistic equation of state (e.g. Peng-Robinson equation of state). Because of partial miscibility, thermodynamic relations are used to model not only interfacial properties but also bulk properties, including density, composition, pressure, and realistic viscosity. As far as we know, this effort is the first time to use diffuse interface modeling based on equation of state for modeling of multi-component two-phase flow with partial miscibility. In numerical simulation, the key issue is to resolve the high contrast of scales from the microscopic interface composition to macroscale bulk fluid motion since the interface has a nanoscale thickness only. To efficiently solve this challenging problem, we develop a multi-scale simulation method. At the microscopic scale, we deduce a reduced interfacial equation under reasonable assumptions, and then we propose a formulation of capillary pressure, which is consistent with macroscale flow equations. Moreover, we show that Young-Laplace equation is an approximation of this capillarity formulation, and this formulation is also consistent with the concept of Tolman length, which is a correction of Young-Laplace equation. At the macroscopical scale, the interfaces are treated as discontinuous surfaces separating two phases of fluids. Our approach differs from conventional sharp-interface two-phase flow model in that we use the capillary pressure directly instead of a combination of surface tension and Young-Laplace equation because capillarity can be calculated from our proposed capillarity formulation. A compatible condition is also derived for the pressure in flow equations. Furthermore, based on the proposed capillarity formulation, we design an efficient numerical method for directly computing the capillary pressure between two fluids composed of multiple components. Finally, numerical tests

  3. Universal quantum computation with Majorana fermion edge modes through microwave spectroscopy of quasi-one-dimensional cold gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Sundar, Bhuvanesh; Mueller, Erich J.

    2013-12-01

    We describe how microwave spectroscopy of cold fermions in quasi-1D traps can be used to detect, manipulate, and entangle exotic nonlocal qubits associated with "Majorana" edge modes. We present different approaches to generate the p-wave superfluidity which is responsible for these topological zero-energy edge modes. We find that the edge modes have clear signatures in the microwave spectrum and that the line shape distinguishes between the degenerate states of a qubit encoded in these edge modes. Moreover, the microwaves rotate the system in its degenerate ground-state manifold. We use these rotations to implement a set of universal quantum gates, allowing the system to be used as a universal quantum computer.

  4. Two-dimensional electron gases in strained quantum wells for AlN/GaN/AlN double heterostructure field-effect transistors on AlN

    NASA Astrophysics Data System (ADS)

    Li, Guowang; Song, Bo; Ganguly, Satyaki; Zhu, Mingda; Wang, Ronghua; Yan, Xiaodong; Verma, Jai; Protasenko, Vladimir; Grace Xing, Huili; Jena, Debdeep

    2014-05-01

    Double heterostructures of strained GaN quantum wells (QWs) sandwiched between relaxed AlN layers provide a platform to investigate the quantum-confined electronic and optical properties of the wells. The growth of AlN/GaN/AlN heterostructures with varying GaN quantum well thicknesses on AlN by plasma molecular beam epitaxy (MBE) is reported. Photoluminescence spectra provide the optical signature of the thin GaN QWs. Reciprocal space mapping in X-ray diffraction shows that a GaN layer as thick as ˜28 nm is compressively strained to the AlN layer underneath. The density of the polarization-induced two-dimensional electron gas (2DEG) in the undoped heterostructures increases with the GaN QW thickness, reaching ˜2.5 × 1013/cm2. This provides a way to tune the 2DEG channel density without changing the thickness of the top barrier layer. Electron mobilities less than ˜400 cm2/Vs are observed, leaving ample room for improvement. Nevertheless, owing to the high 2DEG density, strained GaN QW field-effect transistors with MBE regrown ohmic contacts exhibit an on-current density ˜1.4 A/mm, a transconductance ˜280 mS/mm, and a cut off frequency fT˜104 GHz for a 100-nm-gate-length device. These observations indicate high potential for high-speed radio frequency and high voltage applications that stand to benefit from the extreme-bandgap and high thermal conductivity of AlN.

  5. Two-dimensional electron gases in strained quantum wells for AlN/GaN/AlN double heterostructure field-effect transistors on AlN

    SciTech Connect

    Li, Guowang; Song, Bo; Ganguly, Satyaki; Zhu, Mingda; Wang, Ronghua; Yan, Xiaodong; Verma, Jai; Protasenko, Vladimir; Grace Xing, Huili; Jena, Debdeep

    2014-05-12

    Double heterostructures of strained GaN quantum wells (QWs) sandwiched between relaxed AlN layers provide a platform to investigate the quantum-confined electronic and optical properties of the wells. The growth of AlN/GaN/AlN heterostructures with varying GaN quantum well thicknesses on AlN by plasma molecular beam epitaxy (MBE) is reported. Photoluminescence spectra provide the optical signature of the thin GaN QWs. Reciprocal space mapping in X-ray diffraction shows that a GaN layer as thick as ∼28 nm is compressively strained to the AlN layer underneath. The density of the polarization-induced two-dimensional electron gas (2DEG) in the undoped heterostructures increases with the GaN QW thickness, reaching ∼2.5 × 10{sup 13}/cm{sup 2}. This provides a way to tune the 2DEG channel density without changing the thickness of the top barrier layer. Electron mobilities less than ∼400 cm{sup 2}/Vs are observed, leaving ample room for improvement. Nevertheless, owing to the high 2DEG density, strained GaN QW field-effect transistors with MBE regrown ohmic contacts exhibit an on-current density ∼1.4 A/mm, a transconductance ∼280 mS/mm, and a cut off frequency f{sub T}∼104 GHz for a 100-nm-gate-length device. These observations indicate high potential for high-speed radio frequency and high voltage applications that stand to benefit from the extreme-bandgap and high thermal conductivity of AlN.

  6. Energy-pressure relation for low-dimensional gases

    NASA Astrophysics Data System (ADS)

    Mancarella, Francesco; Mussardo, Giuseppe; Trombettoni, Andrea

    2014-10-01

    means of ultracold atom set-ups [11-14,17], where bosons are confined within 1d atom waveguides which freeze almost all transverse degrees of freedom [18-20]. The coupling strength of the LL system can be tuned through the Feshbach resonance mechanism [21].Our second paradigmatic example will be the 2d ideal anyonic gases in which we will study the energy-pressure relation in the interpolation between 2d Bose and Fermi gases induced by the pure statistical Aharonov-Bohm interactions. We will consider Abelian and non-Abelian Chern-Simons particle systems, and both models admit a soft-core generalization that can be understood as the result of an additional contact interaction besides the pure statistical one. As it is well known, quantum two-dimensional systems of indistinguishable particles have the peculiarity of admitting generalized braiding statistics, because of the non-trivial topological structure of braiding transformations defined over the space-time ambient manifold. Ordinary bosonic and fermionic quantum statistics in 2d admit the generalization represented by Abelian anyons, where an elementary braiding operation is encoded in terms of a multiplicative phase factor acting on the multi-anyonic scalar wavefunction [22-26]. A different generalization of the standard quantum statistics is represented by non-Abelian anyons, described by a multi-component many-body wavefunction and corresponding to higher-dimensional representations of the braid group: non-Abelian anyons generalize the parastatistics, exactly in the same manner in which Abelian anyons generalize Bose and Fermi statistics.Thermodynamic properties of ideal Abelian anyonic gas (assuming hard-core boundary conditions for the wavefunction at coincident points) were studied in the low-density regime [27]: the exact expression therein obtained for the second virial coefficient is periodic and non-analytic as a function of the statistical parameter. Different approaches have been subsequently used in

  7. On the origin of multi-component bulk metallic glasses: Atomic size mismatches and de-mixing

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Dice, Bradley; Liu, Yanhui; Schroers, Jan; Shattuck, Mark D.; O'Hern, Corey S.

    2015-08-01

    The likelihood that an undercooled liquid vitrifies or crystallizes depends on the cooling rate R . The critical cooling rate R c , below which the liquid crystallizes upon cooling, characterizes the glass-forming ability (GFA) of the system. While pure metals are typically poor glass formers with R c > 1 0 12 K/s , specific multi-component alloys can form bulk metallic glasses (BMGs) even at cooling rates below R ˜ 1 K / s . Conventional wisdom asserts that metal alloys with three or more components are better glass formers (with smaller R c ) than binary alloys. However, there is currently no theoretical framework that provides quantitative predictions for R c for multi-component alloys. In this manuscript, we perform simulations of ternary hard-sphere systems, which have been shown to be accurate models for the glass-forming ability of BMGs, to understand the roles of geometric frustration and demixing in determining R c . Specifically, we compress ternary hard sphere mixtures into jammed packings and measure the critical compression rate, below which the system crystallizes, as a function of the diameter ratios σB/σA and σC/σA and number fractions xA, xB, and xC. We find two distinct regimes for the GFA in parameter space for ternary hard spheres. When the diameter ratios are close to 1, such that the largest (A) and smallest (C) species are well-mixed, the GFA of ternary systems is no better than that of the optimal binary glass former. However, when σC/σA ≲ 0.8 is below the demixing threshold for binary systems, adding a third component B with σC < σB < σA increases the GFA of the system by preventing demixing of A and C. Analysis of the available data from experimental studies indicates that most ternary BMGs are below the binary demixing threshold with σC/σA < 0.8.

  8. Unmanned Aerial Systems as Part of a Multi-Component Assessment Strategy to Address Climate Change and Atmospheric Processes

    NASA Astrophysics Data System (ADS)

    Lange, Manfred; Vrekoussis, Mihalis; Sciare, Jean; Argyrides, Marios; Ioannou, Stelios; Keleshis, Christos

    2015-04-01

    Unmanned Aerial Systems (UAS) have been established as versatile tools for different applications, providing data and observations for atmospheric and Earth-Systems research. They offer an urgently needed link between in-situ ground based measurements and satellite remote sensing observations and are distinguished by significant versatility, flexibility and moderate operational costs. UAS have the proven potential to contribute to a multi-component assessment strategy that combines remote-sensing, numerical modelling and surface measurements in order to elucidate important atmospheric processes. This includes physical and chemical transformations related to ongoing climate change as well as issues linked to aerosol-cloud interactions and air quality. The distinct advantages offered by UAS comprise, to name but a few: (i) their ability to operate from altitudes of a few meters to up to a few kilometers; (ii) their capability to perform autonomously controlled missions, which provides for repeat-measurements to be carried out at precisely defined locations; (iii) their relative ease of operation, which enables flexible employment at short-term notice and (iv) the employment of more than one platform in stacked formation, which allows for unique, quasi-3D-observations of atmospheric properties and processes. These advantages are brought to bear in combining in-situ ground based observations and numerical modeling with UAS-based remote sensing in elucidating specific research questions that require both horizontally and vertically resolved measurements at high spatial and temporal resolutions. Employing numerical atmospheric modelling, UAS can provide survey information over spatially and temporally localized, focused areas of evolving atmospheric phenomena, as they become identified by the numerical models. Conversely, UAS observations offer urgently needed data for model verification and provide boundary conditions for numerical models. In this presentation, we will

  9. On the origin of multi-component bulk metallic glasses: Atomic size mismatches and de-mixing.

    PubMed

    Zhang, Kai; Dice, Bradley; Liu, Yanhui; Schroers, Jan; Shattuck, Mark D; O'Hern, Corey S

    2015-08-01

    The likelihood that an undercooled liquid vitrifies or crystallizes depends on the cooling rate R. The critical cooling rate R(c), below which the liquid crystallizes upon cooling, characterizes the glass-forming ability (GFA) of the system. While pure metals are typically poor glass formers with R(c)>10(12)K/s, specific multi-component alloys can form bulk metallic glasses (BMGs) even at cooling rates below R∼1 K/s. Conventional wisdom asserts that metal alloys with three or more components are better glass formers (with smaller R(c)) than binary alloys. However, there is currently no theoretical framework that provides quantitative predictions for R(c) for multi-component alloys. In this manuscript, we perform simulations of ternary hard-sphere systems, which have been shown to be accurate models for the glass-forming ability of BMGs, to understand the roles of geometric frustration and demixing in determining R(c). Specifically, we compress ternary hard sphere mixtures into jammed packings and measure the critical compression rate, below which the system crystallizes, as a function of the diameter ratios σ(B)/σ(A) and σ(C)/σ(A) and number fractions x(A), x(B), and x(C). We find two distinct regimes for the GFA in parameter space for ternary hard spheres. When the diameter ratios are close to 1, such that the largest (A) and smallest (C) species are well-mixed, the GFA of ternary systems is no better than that of the optimal binary glass former. However, when σ(C)/σ(A) ≲ 0.8 is below the demixing threshold for binary systems, adding a third component B with σ(C) < σ(B) < σ(A) increases the GFA of the system by preventing demixing of A and C. Analysis of the available data from experimental studies indicates that most ternary BMGs are below the binary demixing threshold with σ(C)/σ(A) < 0.8. PMID:26254655

  10. Collective modes in cold paramagnetic gases

    SciTech Connect

    Andreeva, T L; Rubin, P L

    2014-02-28

    We have obtained a condition for the emergence of spin waves in paramagnetic gases Re >> ImÂ, which is fulfilled only at temperatures of the order of 1 μK. (laser applications and other topics in quantum electronics)

  11. Separation of polar gases from nonpolar gases

    DOEpatents

    Kulprathipanja, S.; Kulkarni, S.S.

    1986-08-26

    Polar gases such as hydrogen sulfide, sulfur dioxide and ammonia may be separated from nonpolar gases such as methane, nitrogen, hydrogen or carbon dioxide by passing a mixture of polar and nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The use of such membranes as exemplified by polyethylene glycol and silicon rubber composited on polysulfone will permit greater selectivity accompanied by a high flux rate in the separation process.

  12. Separation of polar gases from nonpolar gases

    DOEpatents

    Kulprathipanja, Santi; Kulkarni, Sudhir S.

    1986-01-01

    Polar gases such as hydrogen sulfide, sulfur dioxide and ammonia may be separated from nonpolar gases such as methane, nitrogen, hydrogen or carbon dioxide by passing a mixture of polar and nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The use of such membranes as exemplified by polyethylene glycol and silicon rubber composited on polysulfone will permit greater selectivity accompanied by a high flux rate in the separation process.

  13. Separation of polar gases from nonpolar gases

    DOEpatents

    Kulprathipanja, S.

    1986-08-19

    The separation of polar gases from nonpolar gases may be effected by passing a mixture of nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The porous support is pretreated prior to casting of the mixture thereon by contact with a polyhydric alcohol whereby the pores of the support are altered, thus adding to the increased permeability of the polar gas.

  14. Separation of polar gases from nonpolar gases

    DOEpatents

    Kulprathipanja, Santi

    1986-01-01

    The separation of polar gases from nonpolar gases may be effected by passing a mixture of nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The porous support is pretreated prior to casting of the mixture thereon by contact with a polyhydric alcohol whereby the pores of the support are altered, thus adding to the increased permeability of the polar gas.

  15. Determination of contents of four alkaloids in Pericarpium arecae by quantitative analysis of multi-components by single-marker.

    PubMed

    Yu, Hongli; Tang, Lijuan; Wu, Hao; Wang, Kuilong; Cai, Baochang; Zhang, Xingde; Zhang, Chengchao; Yin, Yunzhi

    2016-07-01

    By using a typical component in traditional Chinese medicine Pericarpium Arecae (PA), quantitative analysis of multi-components by single-marker (QAMS) was performed to determine the contents of four alkaloids. With a column packed with strong cation exchange bonded silica particles, the alkaloids were well separated, showing linear relationships within certain ranges. The limit of detection, limit of quantitation, precision, stability, repeatability and recovery all met requirements. By employing arecoline as internal standard, relative correction factors for arecaidine, guvacine and guvacoline at five concentrations were detected with three HPLC systems and three HPLC columns. The peaks of arecaidine, guvacine and guvacoline were positioned, during which the columns with the same packing materials from different manufacturers significantly affected relative retention values and retention time differences of the alkaloids. However, the columns, from different batches, managed to give relative retention values satisfying the requirements of HPLC peak positioning. The Thermo Fisher Scientific column packed with strong cation exchange bonded silica particles was finally selected by considering resolution and peak time. Compared with the external standard method, QAMS detected the alkaloid contents in 12 PA samples more accurately and reliably. The results provide valuable evidence for content determination and quality control of alkaloids in PA. PMID:27393441

  16. Synchrotron-Based Microspectroscopic Analysis of Molecular and Biopolymer Structures Using Multivariate Techniques and Advanced Multi-Components Modeling

    SciTech Connect

    Yu, P.

    2008-01-01

    More recently, advanced synchrotron radiation-based bioanalytical technique (SRFTIRM) has been applied as a novel non-invasive analysis tool to study molecular, functional group and biopolymer chemistry, nutrient make-up and structural conformation in biomaterials. This novel synchrotron technique, taking advantage of bright synchrotron light (which is million times brighter than sunlight), is capable of exploring the biomaterials at molecular and cellular levels. However, with the synchrotron RFTIRM technique, a large number of molecular spectral data are usually collected. The objective of this article was to illustrate how to use two multivariate statistical techniques: (1) agglomerative hierarchical cluster analysis (AHCA) and (2) principal component analysis (PCA) and two advanced multicomponent modeling methods: (1) Gaussian and (2) Lorentzian multi-component peak modeling for molecular spectrum analysis of bio-tissues. The studies indicated that the two multivariate analyses (AHCA, PCA) are able to create molecular spectral corrections by including not just one intensity or frequency point of a molecular spectrum, but by utilizing the entire spectral information. Gaussian and Lorentzian modeling techniques are able to quantify spectral omponent peaks of molecular structure, functional group and biopolymer. By application of these four statistical methods of the multivariate techniques and Gaussian and Lorentzian modeling, inherent molecular structures, functional group and biopolymer onformation between and among biological samples can be quantified, discriminated and classified with great efficiency.

  17. Effectiveness of a Multi-Component Intervention for Overweight and Obese Children (Nereu Program): A Randomized Controlled Trial

    PubMed Central

    Serra-Paya, Noemi; Ensenyat, Assumpta; Castro-Viñuales, Iván; Real, Jordi; Sinfreu-Bergués, Xènia; Zapata, Amalia; Mur, Jose María; Galindo-Ortego, Gisela; Solé-Mir, Eduard; Teixido, Concepció

    2015-01-01

    Introduction Treatment of childhood obesity is a complex challenge for primary health care professionals. Objectives To evaluate the effectiveness of the Nereu Program in improving anthropometric parameters, physical activity and sedentary behaviours, and dietary intake. Methods Randomized, controlled, multicentre clinical trial comparing Nereu Program and usual counselling group interventions in primary care settings. The 8-month study recruited 113 children aged 6 to 12 years with overweight/obesity. Before recruitment, eligible participants were randomly allocated to an intensive, family-based multi-component behavioural intervention (Nereu Program group) or usual advice from their paediatrician on healthy eating and physical activity. Anthropometric parameters, objectively measured sedentary and physical activity behaviours, and dietary intake were evaluated pre- and post-intervention. Results At the end of the study period, both groups achieved a similar decrease in body mass index (BMIsd) compared to baseline. Nereu Program participants (n = 54) showed greater increases in moderate-intense physical activity (+6.27% vs. -0.61%, p<0.001) and daily fruit servings (+0.62 vs. +0.13, p<0.026), and decreased daily soft drinks consumption (-0.26 vs. -0.02, p<0.047), respectively, compared to the counselling group (n = 59). Conclusions At the end of the 8-month intervention, participants in the Nereu Program group showed improvement in physical activity and dietary behaviours, compared to the counselling group. Trial Registration ClinicalTrials.gov NCT01878994 PMID:26658988

  18. Multi-component immunochromatographic assay for simultaneous detection of aflatoxin B1, ochratoxin A and zearalenone in agro-food.

    PubMed

    Li, Xin; Li, Peiwu; Zhang, Qi; Li, Ran; Zhang, Wen; Zhang, Zhaowei; Ding, Xiaoxia; Tang, Xiaoqian

    2013-11-15

    Mycotoxins are highly toxic contaminants and have induced health threat to human and animals. Aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEA) commonly occur in food and feed. A multi-component immunochromatographic assay (ICA) was developed for rapid and simultaneous determination of these three mycotoxins in agro-food. The strategy was performed based on the competitive immunoreactions between antibody-colloidal gold nanoparticle conjugate probes and mycotoxins or mycotixin antigens. Each monoclonal antibody specially recognize its corresponding mycotoxin and antigen, and there was no cross reactivity in the assay. Three mycotixin antigens were immobilized as three test lines in the nitrocellulose membrane reaction zone, which enable the simultaneous detection in one single test. The visible ICA results were obtained in 20 min. The visual detection limits of this strip test for the AFB1, OTA and ZEA were 0.25 ng/mL, 0.5 ng/mL and 1 ng/mL, respectively. The assay was evaluated using spiked and naturally contaminated peanuts, maize and rice samples. The results were in accordance with those obtained using enzyme-linked immunosorbent assay. In summary, this developed ICA could provide an effective and rapid approach for onsite detection of multi-mycotoxin in agro-food samples without any expensive instrument. PMID:23807236

  19. Frequency-wavenumber implementation for P- and S-wave separation from multi-component seismic data

    NASA Astrophysics Data System (ADS)

    Li, Zhiyuan; Ma, Xiaona; Fu, Chao; Gu, Bingluo; Liang, Guanghe

    2016-03-01

    In this paper, we present a frequency-wavenumber domain scheme to separate P- and S-waves from multi-component seismic data at the free surface. Based on the relationship between the P- and S-wave separated elastic equation, and the divergence and curl operators, we modify the equation to make it applicable to surface seismic data. In the modified equation, the P-wavenumber is chosen to reject the P-waves, and the S-wavenumber is chosen to eliminate the S-waves. The changes in the P-S amplitude ratio caused by the wavenumber choice are corrected. For the free surface condition, an up-going wavefield separation filter is introduced into the modified equation, which can remove the free surface effects from the surface seismic data. In the case of a free surface exhibiting lateral heterogeneity, the seismic data are first transformed into the frequency domain using the fast Fourier transform (FFT), and then are transformed into the wavenumber domain using the discrete Fourier transform (DFT). In the second transform using the DFT, the modified equation is used to separate the P- and S-waves. Numerical tests on synthetic data for three models demonstrate the good performance and accuracy of the scheme.

  20. Improving the Psychosocial Work Environment at Multi-Ethnic Workplaces: A Multi-Component Intervention Strategy in the Cleaning Industry

    PubMed Central

    Smith, Louise Hardman; Hviid, Kirsten; Frydendall, Karen Bo; Flyvholm, Mari-Ann

    2013-01-01

    Global labour migration has increased in recent years and immigrant workers are often recruited into low status and low paid jobs such as cleaning. Research in a Danish context shows that immigrants working in the cleaning industry often form social networks based on shared languages and backgrounds, and that conflict between different ethnic groups may occur. This paper evaluates the impact of a multi-component intervention on the psychosocial work environment at a multi-ethnic Danish workplace in the cleaning sector. The intervention included Danish lessons, vocational training courses, and activities to improve collaboration across different groups of cleaners. Interviews about the outcome of the intervention were conducted with the cleaners and their supervisor. The Copenhagen Psychosocial Questionnaire was used as a supplement to the interviews. The results suggest that the psychosocial work environment had improved after the intervention. According to the interviews with the cleaners, the intervention had led to improved communication, trust, and collaboration. These findings are supported by the questionnaire where social support from supervisor and colleagues, social community, trust, and teamwork seem to have improved together with meaning of work, rewards, and emotional demands. The design of the intervention may provide inspiration for future psychosocial work environment interventions at multi-ethnic work places. PMID:24129115

  1. Beyond sodefrin: evidence for a multi-component pheromone system in the model newt Cynops pyrrhogaster (Salamandridae).

    PubMed

    Van Bocxlaer, Ines; Maex, Margo; Treer, Dag; Janssenswillen, Sunita; Janssens, Rik; Vandebergh, Wim; Proost, Paul; Bossuyt, Franky

    2016-01-01

    Sodefrin, a decapeptide isolated from the male dorsal gland of the Japanese fire belly newt Cynops pyrrhogaster, was the first peptide pheromone identified from a vertebrate. The fire belly salamander and sodefrin have become a model for sex pheromone investigation in aquatically courting salamanders ever since. Subsequent studies in other salamanders identified SPF protein courtship pheromones of around 20 kDa belonging to the same gene-family. Although transcripts of these proteins could be PCR-amplified in Cynops, it is currently unknown whether they effectively use full-length SPF pheromones next to sodefrin. Here we combined transcriptomics, proteomics and phylogenetics to investigate SPF pheromone use in Cynops pyrrhogaster. Our data show that not sodefrin transcripts, but multiple SPF transcripts make up the majority of the expression profile in the dorsal gland of this newt. Proteome analyses of water in which a male has been courting confirm that this protein blend is effectively secreted and tail-fanned to the female. By combining phylogenetics and expression data, we show that independent evolutionary lineages of these SPF's were already expressed in ancestral Cynops species before the origin of sodefrin. Extant Cynops species continue to use this multi-component pheromone system, consisting of various proteins in addition to a lineage-specific peptide. PMID:26935790

  2. A sensitive and quantitative fluorescent multi-component immuno-chromatographic sensor for β-agonist residues.

    PubMed

    Wang, Peilong; Wang, Zhi; Su, Xiaoou

    2015-02-15

    A sensitive and quantitative fluorescent multi-component immuno-chromatographic sensor was developed for detection of three β-agonizts: clenbuterol, ractopamine and salbuterol. A competitive immune strategy between antibody conjugated fluorescent beads and β-agonist or their antigens was employed. Each monoclonal antibody specifically recognizes it is corresponding β-agonist in the conjugating zone. The unreacted antibodies were captured by β-agonist antigens immobilized at three test lines in nitrocellulose membrane reaction zone. This enables simultaneous detection of 3 β-agonizts in one single test without any further sample preparation. The test results can be obtained within 10 min. Limit of detections for clenbuterol, ractopamine and salbuterol were 0.10 ng/mL, 0.10 ng/mL and 0.09 ng/mL, respectively. Recoveries ranged from 70.0% to 100.5% and relative standard deviations were below 15%. The assay was evaluated using spiked and real samples and the results were compared with LC-MS/MS. The developed novel assay method provides a low cost, sensitive and rapid approach for on site detection of β-agonizts. PMID:25310481

  3. Mean-field approach in the multi-component gas of interacting particles applied to relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Anchishkin, D.; Vovchenko, V.

    2015-10-01

    A generalized mean-field approach for the thermodynamic description of relativistic single- and multi-component gas in the grand canonical ensemble is formulated. In the framework of the proposed approach, different phenomenological excluded-volume procedures are presented and compared to the existing ones. The mean-field approach is then used to effectively include hard-core repulsion in hadron-resonance gas model for description of chemical freeze-out in heavy-ion collisions. We calculate the collision energy dependence of several quantities for different values of hard-core hadron radius and for different excluded-volume procedures such as the van der Waals and Carnahan-Starling models. It is shown that a choice of the excluded-volume model becomes important for large particle densities. For large enough values of hadron radii (r≳ 0.9 fm) there can be a sizable difference between different excluded-volume procedures used to describe the chemical freeze-out in heavy-ion collisions. At the same time, for the smaller and more commonly used values of hard-core hadron radii (r≲ 0.5 fm), the precision of the van der Waals excluded-volume procedure is shown to be sufficient.

  4. Improving the psychosocial work environment at multi-ethnic workplaces: a multi-component intervention strategy in the cleaning industry.

    PubMed

    Smith, Louise Hardman; Hviid, Kirsten; Frydendall, Karen Bo; Flyvholm, Mari-Ann

    2013-10-01

    Global labour migration has increased in recent years and immigrant workers are often recruited into low status and low paid jobs such as cleaning. Research in a Danish context shows that immigrants working in the cleaning industry often form social networks based on shared languages and backgrounds, and that conflict between different ethnic groups may occur. This paper evaluates the impact of a multi-component intervention on the psychosocial work environment at a multi-ethnic Danish workplace in the cleaning sector. The intervention included Danish lessons, vocational training courses, and activities to improve collaboration across different groups of cleaners. Interviews about the outcome of the intervention were conducted with the cleaners and their supervisor. The Copenhagen Psychosocial Questionnaire was used as a supplement to the interviews. The results suggest that the psychosocial work environment had improved after the intervention. According to the interviews with the cleaners, the intervention had led to improved communication, trust, and collaboration. These findings are supported by the questionnaire where social support from supervisor and colleagues, social community, trust, and teamwork seem to have improved together with meaning of work, rewards, and emotional demands. The design of the intervention may provide inspiration for future psychosocial work environment interventions at multi-ethnic work places. PMID:24129115

  5. Beyond sodefrin: evidence for a multi-component pheromone system in the model newt Cynops pyrrhogaster (Salamandridae)

    PubMed Central

    Van Bocxlaer, Ines; Maex, Margo; Treer, Dag; Janssenswillen, Sunita; Janssens, Rik; Vandebergh, Wim; Proost, Paul; Bossuyt, Franky

    2016-01-01

    Sodefrin, a decapeptide isolated from the male dorsal gland of the Japanese fire belly newt Cynops pyrrhogaster, was the first peptide pheromone identified from a vertebrate. The fire belly salamander and sodefrin have become a model for sex pheromone investigation in aquatically courting salamanders ever since. Subsequent studies in other salamanders identified SPF protein courtship pheromones of around 20 kDa belonging to the same gene-family. Although transcripts of these proteins could be PCR-amplified in Cynops, it is currently unknown whether they effectively use full-length SPF pheromones next to sodefrin. Here we combined transcriptomics, proteomics and phylogenetics to investigate SPF pheromone use in Cynops pyrrhogaster. Our data show that not sodefrin transcripts, but multiple SPF transcripts make up the majority of the expression profile in the dorsal gland of this newt. Proteome analyses of water in which a male has been courting confirm that this protein blend is effectively secreted and tail-fanned to the female. By combining phylogenetics and expression data, we show that independent evolutionary lineages of these SPF’s were already expressed in ancestral Cynops species before the origin of sodefrin. Extant Cynops species continue to use this multi-component pheromone system, consisting of various proteins in addition to a lineage-specific peptide. PMID:26935790

  6. A multi-component LC-MS/MS method for detection of ten plant-derived psychoactive substances in urine.

    PubMed

    Björnstad, Kristian; Beck, Olof; Helander, Anders

    2009-04-15

    A sensitive and specific LC-MS/MS method for simultaneous detection of 10 plant-derived psychoactive substances (atropine, N,N-dimethyltryptamine, ephedrine, harmaline, harmine, ibogaine, lysergic acid amide, psilocin, scopolamine and yohimbine) in urine was developed. Direct injection of urine diluted with 3 deuterated internal standards allowed for a readily accessible method suitable for application in clinical intoxication cases. Separation was achieved using reversed phase chromatography and gradient elution with a total analysis time of 14 min. Electrospray ionization was used and ions were monitored in the positive selected reaction monitoring mode. The calibration curves were linear (r(2)>0.999) and the total imprecision at high (1000 microg/L) and low (50 microg/L) substance concentrations were 4.9-13.8% and 8.3-26%, respectively. Infusing the analytes post column and injecting matrix samples showed limited influence by ion suppression. The multi-component method proved to be useful for investigation of authentic cases of intoxication with plant-derived psychoactive drugs and was indicated to cover the clinically relevant concentration ranges. PMID:19332394

  7. Utility of the multi-component training distress scale to monitor swimmers during periods of training overload.

    PubMed

    Main, Luana C; Warmington, Stuart A; Korn, Emily; Gastin, Paul B

    2016-01-01

    The purpose of the present study was to determine the efficacy of the multi-component training distress scale (MTDS), in monitoring swimmers prior to national competition. Twenty-one national-level adolescent swimmers completed eight weeks of testing. Once a week participants completed an 8 × 50 m sprint test, vertical jump test, sit-and-reach test, the MTDS and the Recovery-Stress Questionnaire for Athletes (REST-Q). All testing was incorporated into the swimmers' normal training programme. The REST-Q accounted for the following variances in performance: flexibility (14.6%, p = 0.009), power output (17.7%, p = 0.003), swimming speed (15.5%, p = 0.006) and swimming endurance (17.5%, p = 0.002). In comparison, the MTDS accounted for the following variances in performance: flexibility (12.1%, p = 0.095), power output (16.4%, p = 0.023), swimming speed (20.5%, p = 0.003) and swimming speed endurance (23.8%, p = 0.001). The findings of the current study suggest that both the REST-Q Sport and the MTDS have the capacity to predict performance on a range of fitness components associated with swimming. PMID:27368060

  8. Cooling Atomic Gases With Disorder

    NASA Astrophysics Data System (ADS)

    Paiva, Thereza; Khatami, Ehsan; Yang, Shuxiang; Rousseau, Valéry; Jarrell, Mark; Moreno, Juana; Hulet, Randall G.; Scalettar, Richard T.

    2015-12-01

    Cold atomic gases have proven capable of emulating a number of fundamental condensed matter phenomena including Bose-Einstein condensation, the Mott transition, Fulde-Ferrell-Larkin-Ovchinnikov pairing, and the quantum Hall effect. Cooling to a low enough temperature to explore magnetism and exotic superconductivity in lattices of fermionic atoms remains a challenge. We propose a method to produce a low temperature gas by preparing it in a disordered potential and following a constant entropy trajectory to deliver the gas into a nondisordered state which exhibits these incompletely understood phases. We show, using quantum Monte Carlo simulations, that we can approach the Néel temperature of the three-dimensional Hubbard model for experimentally achievable parameters. Recent experimental estimates suggest the randomness required lies in a regime where atom transport and equilibration are still robust.

  9. Cooling Atomic Gases With Disorder.

    PubMed

    Paiva, Thereza; Khatami, Ehsan; Yang, Shuxiang; Rousseau, Valéry; Jarrell, Mark; Moreno, Juana; Hulet, Randall G; Scalettar, Richard T

    2015-12-11

    Cold atomic gases have proven capable of emulating a number of fundamental condensed matter phenomena including Bose-Einstein condensation, the Mott transition, Fulde-Ferrell-Larkin-Ovchinnikov pairing, and the quantum Hall effect. Cooling to a low enough temperature to explore magnetism and exotic superconductivity in lattices of fermionic atoms remains a challenge. We propose a method to produce a low temperature gas by preparing it in a disordered potential and following a constant entropy trajectory to deliver the gas into a nondisordered state which exhibits these incompletely understood phases. We show, using quantum Monte Carlo simulations, that we can approach the Néel temperature of the three-dimensional Hubbard model for experimentally achievable parameters. Recent experimental estimates suggest the randomness required lies in a regime where atom transport and equilibration are still robust. PMID:26705614

  10. Defect Clustering and Nano-Phase Structure Characterization of Multi-Component Rare Earth Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

    2003-01-01

    Advanced oxide thermal barrier coatings have been developed by incorporating multi-component rare earth oxide dopants into zirconia-yttria to effectively promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nano-scale phases within the coating systems. The presence of these nano-sized defect clusters has found to significantly reduce the coating intrinsic thermal conductivity, improve sintering resistance, and maintain long-term high temperature stability. In this paper, the defect clusters and nano-structured phases, which were created by the addition of multi-component rare earth dopants to the plasma-sprayed and electron-beam physical vapor deposited thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The defect cluster size, distribution, crystallographic and compositional information were investigated using high-resolution TEM lattice imaging, selected area diffraction (SAD), electron energy-loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) analysis techniques. The results showed that substantial defect clusters were formed in the advanced multi-component rare earth oxide doped zirconia- yttria systems. The size of the oxide defect clusters and the cluster dopant segregation was typically ranging from 5 to 50 nm. These multi-component dopant induced defect clusters are an important factor for the coating long-term high temperature stability and excellent performance.

  11. Synthesis of unnatural amino acids via microwave-assisted regio-selective one-pot multi-component reactions of sulfamidates

    EPA Science Inventory

    Synthesis of triazole-based unnatural amino acids, triazole bisaminoacids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW irradiation conditions. The developed method is app...

  12. The Middle School Intervention Project: Use of a Regression Discontinuity Design to Evaluate a Multi-Component Intervention for Struggling Readers in Middle School in Six School Districts

    ERIC Educational Resources Information Center

    Crone, Deanne A.; Stoolmiller, Michael; Baker, Scott K.; Fien, Hank

    2012-01-01

    The primary aim of the Middle School Intervention Project (MSIP) is to evaluate the impact of a multi-component intervention for struggling adolescent readers on reading outcomes. The intervention consists of: (1) targeted, Tier 2 reading and (2) school engagement interventions, and (3) data-based-decision-making (DBDM) teams to review and act on…

  13. The Impact of Modified Multi-Component Cognitive Strategy Instruction in the Acquisition of Metacognitive Strategy Knowledge in the Text Comprehension Process of Students with Mental Retardation

    ERIC Educational Resources Information Center

    Doganay Bilgi, Arzu; Ozmen, E. Ruya

    2014-01-01

    The purpose of this study was to determine the impact of Modified Multi-component Cognitive Strategy Instruction on the metacognitive strategy knowledge used for the comprehension process of descriptive texts for students with mild mental retardation (MMR). Three students with MMR from inclusive classes participated in the study. The study was…

  14. Defect Clustering and Nano-Phase Structure Characterization of Multi-Component Rare Earth Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

    1990-01-01

    Advanced oxide thermal barrier coatings have been developed by incorporating multi- component rare earth oxide dopants into zirconia-yttria to effectively promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nano-scale phases within the coating systems. The presence of these nano-sized defect clusters has found to significantly reduce the coating intrinsic thermal conductivity, improve sintering resistance, and maintain long-term high temperature stability. In this paper, the defect clusters and nano-structured phases, which were created by the addition of multi-component rare earth dopants to the plasma- sprayed and electron-beam physical vapor deposited thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The defect cluster size, distribution, crystallographic and compositional information were investigated using high-resolution TEM lattice imaging, selected area diffraction (SAD), and energy dispersive spectroscopy (EDS) analysis techniques. The results showed that substantial defect clusters were formed in the advanced multi-component rare earth oxide doped zirconia-yttria systems. The size of the oxide defect clusters and the cluster dopant segregation was typically ranging fiom 5 to 50 nm. These multi-component dopant induced defect clusters are an important factor for the coating long-term high temperature stability and excellent performance.

  15. Single, binary and multi-component adsorption of some anions and heavy metals on environmentally friendly Carpobrotus edulis plant.

    PubMed

    Chiban, Mohamed; Soudani, Amina; Sinan, Fouad; Persin, Michel

    2011-02-01

    A low-cost adsorbent and environmentally friendly adsorbent from Carpobrotus edulis plant was used for the removal of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions from single, binary and multi-component systems. The efficiency of the adsorbent was studied using batch adsorption technique under different experimental conditions by varying parameters such as pH, initial concentration and contact time. In single component systems, the dried C. edulis has the highest affinity for Pb(2+), followed by NO(3)(-), Cd(2+) and H(2)PO(4)(-), with adsorption capacities of 175mg/g, 125mg/g, 28mg/g and 26mg/g, respectively. These results showed that the adsorption of NO(3)(-) and H(2)PO(4)(-) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. Freundlich adsorption model, showed the best fit to the single and binary experimental adsorption data. These results also indicated that the adsorption yield of Pb(2+) ion was reduced by the presence of Cd(2+) ion in binary metal mixture. The competitive adsorption of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions on dried C. edulis plant shows that NO(3)(-) and H(2)PO(4)(-) anions are able to adsorb on different free binding sites and Pb(2+) and Cd(2+) cations are able to adsorb on the same active sites of C. edulis particles. The dried C. edulis was found to be efficient in removing nitrate, phosphate, cadmium and lead from aqueous solution as compared to other adsorbents already used for the removal of these ions. PMID:20951008

  16. Testing the Efficacy of a Multi-Component DNA-Prime/DNA-Boost Vaccine against Trypanosoma cruzi Infection in Dogs

    PubMed Central

    Aparicio-Burgos, José E.; Ochoa-García, Laucel; Zepeda-Escobar, José Antonio; Gupta, Shivali; Dhiman, Monisha; Martínez, José Simón; de Oca-Jiménez, Roberto Montes; Arreola, Margarita Val; Barbabosa-Pliego, Alberto; Vázquez-Chagoyán, Juan C.; Garg, Nisha Jain

    2011-01-01

    Background Trypanosoma cruzi, the etiologic agent of Chagas Disease, is a major vector borne health problem in Latin America and an emerging infectious disease in the United States. Methods We tested the efficacy of a multi-component DNA-prime/DNA-boost vaccine (TcVac1) against experimental T. cruzi infection in a canine model. Dogs were immunized with antigen-encoding plasmids and cytokine adjuvants, and two weeks after the last immunization, challenged with T. cruzi trypomastigotes. We measured antibody responses by ELISA and haemagglutination assay, parasitemia and infectivity to triatomines by xenodiagnosis, and performed electrocardiography and histology to assess myocardial damage and tissue pathology. Results Vaccination with TcVac1 elicited parasite-and antigen-specific IgM and IgG (IgG2>IgG1) responses. Upon challenge infection, TcVac1-vaccinated dogs, as compared to non-vaccinated controls dogs, responded to T. cruzi with a rapid expansion of antibody response, moderately enhanced CD8+ T cell proliferation and IFN-γ production, and suppression of phagocytes’ activity evidenced by decreased myeloperoxidase and nitrite levels. Subsequently, vaccinated dogs controlled the acute parasitemia by day 37 pi (44 dpi in non-vaccinated dogs), and exhibited a moderate decline in infectivity to triatomines. TcVac1-immunized dogs did not control the myocardial parasite burden and electrocardiographic and histopatholgic cardiac alterations that are the hallmarks of acute Chagas disease. During the chronic stage, TcVac1-vaccinated dogs exhibited a moderate decline in cardiac alterations determined by EKG and anatomo-/histo-pathological analysis while chronically-infected/non-vaccinated dogs continued to exhibit severe EKG alterations. Conclusions Overall, these results demonstrated that TcVac1 provided a partial resistance to T. cruzi infection and Chagas disease, and provide an impetus to improve the vaccination strategy against Chagas disease. PMID:21625470

  17. A Multi-Component Cognitive-Behavioral Intervention for Sleep Disturbance in Veterans with PTSD: A Pilot Study

    PubMed Central

    Ulmer, Christi S.; Edinger, Jack D.; Calhoun, Patrick S.

    2011-01-01

    Study Objectives: A significant portion of US military personnel are returning from deployment with trauma-related sleep disturbance, and disrupted sleep has been proposed as a mechanism for the development of medical conditions in those with posttraumatic stress disorder (PTSD). Although individuals with PTSD may realize improved sleep with either PTSD treatment or CBT for insomnia, many continue to experience residual sleep difficulties. Newly developed interventions designed to address nightmares are effective to this end, but often do not fully remove all aspects of PTSD-related sleep difficulties when used in isolation. A combined intervention involving both a nightmare-specific intervention and CBT for insomnia may lead to more marked reductions in PTSD-related sleep disturbances. Methods: Twenty-two veterans meeting criteria for PTSD were enrolled in the study. A combined intervention comprised of CBT for insomnia and imagery rehearsal therapy was evaluated against a usual care comparison group. Results: Intent-to-treat analyses revealed medium to large treatment effect sizes for all sleep diary outcomes, and very large treatment effects for insomnia severity, sleep quality, and PTSD symptoms. Conclusions: Findings demonstrate that an intervention targeting trauma-specific sleep disturbance produces large short-term effects, including substantial reductions in PTSD symptoms and insomnia severity. Future research should focus on the optimal approach to the treatment of comorbid PTSD and sleep disturbance in terms of sequencing, and should assure that sleep-focused interventions are available and acceptable to our younger veterans, who were more likely to drop out of treatment. Citation: Ulmer CS; Edinger JD; Calhoun PS. A multi-component cognitive-behavioral intervention for sleep disturbance in veterans with PTSD: a pilot study. J Clin Sleep Med 2011;7(1):57-68. PMID:21344046

  18. A Multi-Component Pheromone in the Urine of Dominant Male Tilapia (Oreochromis mossambicus) Reduces Aggression in Rivals.

    PubMed

    Keller-Costa, Tina; Saraiva, João L; Hubbard, Peter C; Barata, Eduardo N; Canário, Adelino V M

    2016-02-01

    Males often use scent to communicate their dominance, and to mediate aggressive and breeding behaviors. In teleost fish, however, the chemical composition of male pheromones is poorly understood. Male Mozambique tilapia, Oreochromis mossambicus, use urine that signals social status and primes females to spawn. The urinary sex pheromone directed at females consists of 5β-pregnane-3α,17α,20β-triol 3-glucuronate and its 20α-epimer. The concentration of these is positively correlated with male social rank. This study tested whether dominant male urine reduces aggression in receiver males, and whether the pregnanetriol 3-glucuronates also reduce male-male aggression. Males were allowed to fight their mirror image when exposed to either: i) water control or a chemical stimulus; ii) dominant male urine (DMU); iii) C18-solid phase (C18-SPE) DMU eluate; iv) C18-SPE DMU eluate plus filtrate; v) the two pregnanetriol 3-glucuronates (P3Gs); or vi) P3Gs plus DMU filtrate. Control males mounted an increasingly aggressive fight against their image over time. However, DMU significantly reduced this aggressive response. The two urinary P3Gs did not replicate the effect of whole DMU. Neither did the C18-SPE DMU eluate, containing the P3Gs, alone, nor the C18-SPE DMU filtrate to which the two P3Gs were added. Only exposure to reconstituted DMU (C18-SPE eluate plus filtrate) restored the aggression-reducing effect of whole DMU. Olfactory activity was present in the eluate and the polar filtrate in electro-olfactogram studies. We conclude that P3Gs alone have no reducing effect on aggression and that the urinary signal driving off male competition is likely to be a multi-component pheromone, with components present in both the polar and non-polar urine fractions. PMID:26846373

  19. Multi-Component Smoking Cessation Treatment including Mobile Contingency Management for Smoking Cessation in Homeless Veteran Smokers

    PubMed Central

    Carpenter, Vickie L.; Hertzberg, Jeffrey S.; Kirby, Angela C.; Calhoun, Patrick S.; Moore, Scott D.; Dennis, Michelle F.; Dennis, Paul A.; Dedert, Eric A.; Hair, Lauren P.; Beckham, Jean C.

    2015-01-01

    Introduction Smoking rates are 80% among persons who are homeless, and these smokers have decreased odds of quitting smoking. Little is known about relapse rates among homeless smokers, but the dearth of research indicates that more information regarding quit rates in this population is needed. Furthermore, innovative methods are needed to treat smoking cessation among homeless smokers. Web-based contingency management (CM) approaches have been found helpful in reducing smoking among other difficult-to-treat smoker populations but have been generally limited by the need for computers or frequent clinic based carbon monoxide (CO) monitoring. This pilot study builds on a web-based CM approach by evaluating a smart phone based application for CM named mobile CM (mCM). Methods Following a one-week training period, 20 homeless veteran smokers participated in a multi-component smoking cessation intervention including 4 weeks of mCM. All smokers received 4 smoking cessation counseling sessions, nicotine replacement and bupropion (if medically eligible). Participants could earn up to $815 ($480 for mCM, $100 for CO readings showing abstinence at posttreatment and follow up, and $35 for equipment return). Mean compensation for the mCM component was $286 of a possible $480. Results Video transmission compliance was high during the one-week training (97%) and the four-week treatment period (87%). Bioverified 7-day point prevalence abstinence was 50% at four weeks. Follow up bioverified single assessment point prevalence abstinence was 65% at three months and 60% at six months. Conclusions mCM may be a useful adjunctive smoking cessation treatment component for reducing smoking among homeless smokers. PMID:25699616

  20. Multi-component analysis of polar water pollutants using sequential solid-phase extraction followed by LC-ESI-MS.

    PubMed

    Loos, Robert; Hanke, Georg; Eisenreich, Steven J

    2003-06-01

    A multi-component screening analysis method for polar to medium-polar water pollutants was developed. Sample clean-up and group separation are performed by sequential solid-phase extraction (SSPE) using automated SPE with C18 and polymeric sorbent materials. Analyses are performed by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) using a single-quadrupole instrument. More than 90 priority compounds of environmental interest--comprising the most important chemical and substance classes: phenols, carboxylic acids, aromatic sulfonates, aromatic amines, pharmaceuticals, surfactants, dyes, and pesticides--have been chosen for the experiments. The compounds are divided by the SSPE procedure into 3 different polarity classes. The extraction recoveries were determined in the 3 fractions for every single substance, and were for most of the analytes in the range of 50-100%. A mixture of hexane-dichloromethane was used for the elution of nonpolar compounds like alkylphenols from C18. Methanol and acetone are well suited for the elution of more polar substances. The limits of detection (LODs) were determined for all compounds. Effluents from municipal and industrial wastewater treatment plants (WWTPs) treating waste water from textile industries; and the corresponding receiving waters (rivers and lakes) have been analysed with the developed method. Urban and industrial pollution was observed in rivers and streams in the area north of Milan, Italy. In the water samples different phenols (nitrophenols, bisphenol A, nonylphenol), alkylphenol ethoxylate surfactants, their metabolites with endocrine disrupting potential, aromatic sulfonates, linear alkylbenzenesulfonate surfactants, dyes, pesticides, pharmaceuticals, and a dichlorobenzidine compound were identified. PMID:12833980

  1. Influence of Urbanization on Body Size, Condition, and Physiology in an Urban Exploiter: A Multi-Component Approach.

    PubMed

    Meillère, Alizée; Brischoux, François; Parenteau, Charline; Angelier, Frédéric

    2015-01-01

    Consistent expanding urbanization dramatically transforms natural habitats and exposes organisms to novel environmental challenges, often leading to reduced species richness and diversity in cities. However, it remains unclear how individuals are affected by the urban environment and how they can or cannot adjust to the specific characteristics of urban life (e.g. food availability). In this study, we used an integrative multi-component approach to investigate the effects of urbanization on the nutritional status of house sparrows (Passer domesticus). We assessed several morphological and physiological indices of body condition in both juveniles (early post-fledging) and breeding adults from four sites with different levels of urbanization in France, Western Europe. We found that sparrows in more urbanized habitats have reduced body size and body mass compared to their rural conspecifics. However, we did not find any consistent differences in a number of complementary indices of condition (scaled mass index, muscle score, hematocrit, baseline and stress-induced corticosterone levels) between urban and rural birds, indicating that urban sparrows may not be suffering nutritional stress. Our results suggest that the urban environment is unlikely to energetically constrain adult sparrows, although other urban-related variables may constrain them. On the other hand, we found significant difference in juvenile fat scores, suggesting that food types provided to young sparrows differed highly between habitats. In addition to the observed smaller size of urban sparrows, these results suggest that the urban environment is inadequate to satisfy early-life sparrows' nutritional requirements, growth, and development. The urban environment may therefore have life-long consequences for developing birds. PMID:26270531

  2. Influence of Urbanization on Body Size, Condition, and Physiology in an Urban Exploiter: A Multi-Component Approach

    PubMed Central

    Meillère, Alizée; Brischoux, François; Parenteau, Charline; Angelier, Frédéric

    2015-01-01

    Consistent expanding urbanization dramatically transforms natural habitats and exposes organisms to novel environmental challenges, often leading to reduced species richness and diversity in cities. However, it remains unclear how individuals are affected by the urban environment and how they can or cannot adjust to the specific characteristics of urban life (e.g. food availability). In this study, we used an integrative multi-component approach to investigate the effects of urbanization on the nutritional status of house sparrows (Passer domesticus). We assessed several morphological and physiological indices of body condition in both juveniles (early post-fledging) and breeding adults from four sites with different levels of urbanization in France, Western Europe. We found that sparrows in more urbanized habitats have reduced body size and body mass compared to their rural conspecifics. However, we did not find any consistent differences in a number of complementary indices of condition (scaled mass index, muscle score, hematocrit, baseline and stress-induced corticosterone levels) between urban and rural birds, indicating that urban sparrows may not be suffering nutritional stress. Our results suggest that the urban environment is unlikely to energetically constrain adult sparrows, although other urban-related variables may constrain them. On the other hand, we found significant difference in juvenile fat scores, suggesting that food types provided to young sparrows differed highly between habitats. In addition to the observed smaller size of urban sparrows, these results suggest that the urban environment is inadequate to satisfy early-life sparrows’ nutritional requirements, growth, and development. The urban environment may therefore have life-long consequences for developing birds. PMID:26270531

  3. Multi-component analysis of tetracyclines, sulfonamides and tylosin in swine manure by liquid chromatography-tandem mass spectrometry.

    PubMed

    Jacobsen, Anne Marie; Halling-Sørensen, Bent

    2006-03-01

    A multi-component method focussing on thorough sample preparation has been developed for simultaneous analysis of swine manure for three classes of antibiotic-tetracyclines, sulfonamides, and tylosin. Liquid manure was initially freeze-dried and homogenised by pulverization before extraction by pressurised liquid extraction. The extraction was performed at 75 degrees C and 2,500 psig in three steps using two cycles with 0.2 mol L(-1) citric acid buffer (pH 4.7) and one cycle with a mixture of 80% methanol with 0.2 mol L(-1) citric acid (pH 3). After liquid-liquid extraction with heptane to remove lipids, the pH of the manure was adjusted to 3 with formic acid and the sample was vacuum-filtered through 0.6 mum glass-fibre filters. Finally the samples were pre-concentrated by tandem SPE (SAX-HLB). Recoveries were determined for manure samples spiked at three concentrations (50-5,000 microg kg(-1) dry matter); quantification was achieved by matrix-matched calibration. Recoveries were >70% except for oxytetracycline (42-54%), sulfadiazine (59-73%), and tylosin (9-35%) and did not vary with concentration or from day-to-day. Limits of quantification (LOQ) for all compounds, determined as a signal-to-noise ratio of 10, were in the range 10-100 microg kg(-1) dry matter. The suitability of the method was assessed by analysis of swine manure samples from six different pig-production sites, e.g. finishing pigs, sows, or mixed production. Residues of antibiotics were detected in all samples. The largest amounts were found for tetracyclines (up to 30 mg kg(-1) dry matter for the sum of CTC and ECTC). Sulfonamides were detected at concentrations up to 2 mg kg(-1) dry matter (SDZ); tylosin was not detected in any samples. PMID:16485090

  4. The Use of Multi-Component Statistical Techniques in Understanding Subduction Zone Arc Granitic Geochemical Data Sets

    NASA Astrophysics Data System (ADS)

    Pompe, L.; Clausen, B. L.; Morton, D. M.

    2015-12-01

    Multi-component statistical techniques and GIS visualization are emerging trends in understanding large data sets. Our research applies these techniques to a large igneous geochemical data set from southern California to better understand magmatic and plate tectonic processes. A set of 480 granitic samples collected by Baird from this area were analyzed for 39 geochemical elements. Of these samples, 287 are from the Peninsular Ranges Batholith (PRB) and 164 from part of the Transverse Ranges (TR). Principal component analysis (PCA) summarized the 39 variables into 3 principal components (PC) by matrix multiplication and for the PRB are interpreted as follows: PC1 with about 30% of the variation included mainly compatible elements and SiO2 and indicates extent of differentation; PC2 with about 20% of the variation included HFS elements and may indicate crustal contamination as usually identified by Sri; PC3 with about 20% of the variation included mainly HRE elements and may indicate magma source depth as often diplayed using REE spider diagrams and possibly Sr/Y. Several elements did not fit well in any of the three components: Cr, Ni, U, and Na2O.For the PRB, the PC1 correlation with SiO2 was r=-0.85, the PC2 correlation with Sri was r=0.80, and the PC3 correlation with Gd/Yb was r=-0.76 and with Sr/Y was r=-0.66 . Extending this method to the TR, correlations were r=-0.85, -0.21, -0.06, and -0.64, respectively. A similar extent of correlation for both areas was visually evident using GIS interpolation.PC1 seems to do well at indicating differentiation index for both the PRB and TR and correlates very well with SiO2, Al2O3, MgO, FeO*, CaO, K2O, Sc, V, and Co, but poorly with Na2O and Cr. If the crustal component is represented by Sri, PC2 correlates well and less expesively with this indicator in the PRB, but not in the TR. Source depth has been related to the slope on REE spidergrams, and PC3 based on only the HREE and using the Sr/Y ratios gives a reasonable

  5. Roadmap on quantum optical systems

    NASA Astrophysics Data System (ADS)

    Dumke, Rainer; Lu, Zehuang; Close, John; Robins, Nick; Weis, Antoine; Mukherjee, Manas; Birkl, Gerhard; Hufnagel, Christoph; Amico, Luigi; Boshier, Malcolm G.; Dieckmann, Kai; Li, Wenhui; Killian, Thomas C.

    2016-09-01

    This roadmap bundles fast developing topics in experimental optical quantum sciences, addressing current challenges as well as potential advances in future research. We have focused on three main areas: quantum assisted high precision measurements, quantum information/simulation, and quantum gases. Quantum assisted high precision measurements are discussed in the first three sections, which review optical clocks, atom interferometry, and optical magnetometry. These fields are already successfully utilized in various applied areas. We will discuss approaches to extend this impact even further. In the quantum information/simulation section, we start with the traditionally successful employed systems based on neutral atoms and ions. In addition the marvelous demonstrations of systems suitable for quantum information is not progressing, unsolved challenges remain and will be discussed. We will also review, as an alternative approach, the utilization of hybrid quantum systems based on superconducting quantum devices and ultracold atoms. Novel developments in atomtronics promise unique access in exploring solid-state systems with ultracold gases and are investigated in depth. The sections discussing the continuously fast-developing quantum gases include a review on dipolar heteronuclear diatomic gases, Rydberg gases, and ultracold plasma. Overall, we have accomplished a roadmap of selected areas undergoing rapid progress in quantum optics, highlighting current advances and future challenges. These exciting developments and vast advances will shape the field of quantum optics in the future.

  6. Positron-attachment to small molecules: Vibrational enhancement of positron affinities with configuration interaction level of multi-component molecular orbital approach

    SciTech Connect

    Tachikawa, Masanori

    2015-12-31

    To theoretically demonstrate the binding of a positron to small polarized molecules, we have calculated the vibrational averaged positron affinity (PA) values along the local vibrational contribution with the configuration interaction level of multi-component molecular orbital method. This method can take the electron-positron correlation contribution into account through single electronic - single positronic excitation configurations. The PA values are enhanced by including the local vibrational contribution from vertical PA values due to the anharmonicity of the potential.

  7. Transport of Trace Gases

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.

    2005-01-01

    Trace gases measurements are used to diagnose both the chemistry and transport of the atmosphere. These lectures emphasize the interpretation of trace gases measurements and techniques used to untangle chemistry and transport effects. I will discuss PV transform, trajectory techniques, and age-of-air as far as the circulation of the stratosphere.

  8. The use of net analyte signal orthogonalization in the separation of multi-component diffraction patterns obtained from X-ray powder diffraction of intact compacts.

    PubMed

    Moore, Michael D; Cogdill, Robert P; Short, Steven M; Hair, Colleen R; Wildfong, Peter L D

    2008-06-01

    X-ray powder diffraction (XRPD) analysis of intact multi-component consolidated mixtures has significant potential owing to the ability to non-destructively quantify and discriminate between solid phases in composite bodies with minimal sample preparation. There are, however, limitations to the quantitative power using traditional univariate methods on diffraction data containing features from all components in the system. The ability to separate multi-component diffraction data into patterns representing single constituents allows both composition as well as physical phenomena associated with the individual components of complex systems to be probed. Intact, four-component compacts, consisting of two crystalline and two amorphous constituents were analyzed using XRPD configured in both traditional Bragg-Brentano reflectance geometry and parallel-beam transmission geometry. Two empirical, model-based methods consisting of a multiple step net analyte signal (NAS) orthogonalization are presented as ways to separate multi-component XRPD patterns into single constituent patterns. Multivariate figures of merit (FOM) were calculated for each of the isolated constituents to compare method-specific parameters such as sensitivity, selectivity, and signal-to-noise, enabling quantitative comparisons between the two modes of XRPD analysis. PMID:18294800

  9. The cost-effectiveness of multi-component interventions to prevent delirium in older people undergoing surgical repair of hip fracture.

    PubMed

    Akunne, Anayo; Davis, Sarah; Westby, Maggie; Young, John

    2014-02-01

    This article summarizes the detailed cost-effectiveness analysis of delirium prevention interventions in people undergoing surgical repair of hip fracture. We compared a multi-component delirium prevention intervention with usual care using a model based on a decision tree analysis. The model was used to estimate the incremental net monetary benefit (INMB). The robustness of the cost-effectiveness result was explored using deterministic and probabilistic sensitivity analyses. The multi-component prevention intervention was cost-effective when compared to usual care. It was associated with an INMB of £8,180 using a cost-effectiveness threshold of £20,000 per QALY. It remained cost-effective in the majority of the deterministic sensitivity analyses and was cost-effective in 96.4 % of the simulations carried out in the probabilistic sensitivity analysis. We have demonstrated the cost-effectiveness of a multi-component delirium prevention intervention that targets modifiable risk factors for delirium in older people undergoing surgical repair of hip fracture. It is an attractive intervention for practitioners and health care policy makers as they address the double burden of hip fracture and delirium. PMID:23412312

  10. Quantum memory Quantum memory

    NASA Astrophysics Data System (ADS)

    Le Gouët, Jean-Louis; Moiseev, Sergey

    2012-06-01

    Interaction of quantum radiation with multi-particle ensembles has sparked off intense research efforts during the past decade. Emblematic of this field is the quantum memory scheme, where a quantum state of light is mapped onto an ensemble of atoms and then recovered in its original shape. While opening new access to the basics of light-atom interaction, quantum memory also appears as a key element for information processing applications, such as linear optics quantum computation and long-distance quantum communication via quantum repeaters. Not surprisingly, it is far from trivial to practically recover a stored quantum state of light and, although impressive progress has already been accomplished, researchers are still struggling to reach this ambitious objective. This special issue provides an account of the state-of-the-art in a fast-moving research area that makes physicists, engineers and chemists work together at the forefront of their discipline, involving quantum fields and atoms in different media, magnetic resonance techniques and material science. Various strategies have been considered to store and retrieve quantum light. The explored designs belong to three main—while still overlapping—classes. In architectures derived from photon echo, information is mapped over the spectral components of inhomogeneously broadened absorption bands, such as those encountered in rare earth ion doped crystals and atomic gases in external gradient magnetic field. Protocols based on electromagnetic induced transparency also rely on resonant excitation and are ideally suited to the homogeneous absorption lines offered by laser cooled atomic clouds or ion Coulomb crystals. Finally off-resonance approaches are illustrated by Faraday and Raman processes. Coupling with an optical cavity may enhance the storage process, even for negligibly small atom number. Multiple scattering is also proposed as a way to enlarge the quantum interaction distance of light with matter. The

  11. Nonaqueous Phase Liquid Dissolution in Porous Media: Multi-Scale Effects of Multi-Component Dissolution Kinetics on Cleanup Time

    SciTech Connect

    McNab, W; Ezzedine, S; Detwiler, R

    2007-02-26

    Industrial organic solvents such as trichloroethylene (TCE) and tetrachloroethylene (PCE) constitute a principal class of groundwater contaminants. Cleanup of groundwater plume source areas associated with these compounds is problematic, in part, because the compounds often exist in the subsurface as dense nonaqueous phase liquids (DNAPLs). Ganglia (or 'blobs') of DNAPL serve as persistent sources of contaminants that are difficult to locate and remediate (e.g. Fenwick and Blunt, 1998). Current understanding of the physical and chemical processes associated with dissolution of DNAPLs in the subsurface is incomplete and yet is critical for evaluating long-term behavior of contaminant migration, groundwater cleanup, and the efficacy of source area cleanup technologies. As such, a goal of this project has been to contribute to this critical understanding by investigating the multi-phase, multi-component physics of DNAPL dissolution using state-of-the-art experimental and computational techniques. Through this research, we have explored efficient and accurate conceptual and numerical models for source area contaminant transport that can be used to better inform the modeling of source area contaminants, including those at the LLNL Superfund sites, to re-evaluate existing remediation technologies, and to inspire or develop new remediation strategies. The problem of DNAPL dissolution in natural porous media must be viewed in the context of several scales (Khachikian and Harmon, 2000), including the microscopic level at which capillary forces, viscous forces, and gravity/buoyancy forces are manifested at the scale of individual pores (Wilson and Conrad, 1984; Chatzis et al., 1988), the mesoscale where dissolution rates are strongly influenced by the local hydrodynamics, and the field-scale. Historically, the physico-chemical processes associated with DNAPL dissolution have been addressed through the use of lumped mass transfer coefficients which attempt to quantify the

  12. Notes on Well-Posed, Ensemble Averaged Conservation Equations for Multiphase, Multi-Component, and Multi-Material Flows

    SciTech Connect

    Ray A. Berry

    2005-07-01

    At the INL researchers and engineers routinely encounter multiphase, multi-component, and/or multi-material flows. Some examples include: Reactor coolant flows Molten corium flows Dynamic compaction of metal powders Spray forming and thermal plasma spraying Plasma quench reactor Subsurface flows, particularly in the vadose zone Internal flows within fuel cells Black liquor atomization and combustion Wheat-chaff classification in combine harvesters Generation IV pebble bed, high temperature gas reactor The complexity of these flows dictates that they be examined in an averaged sense. Typically one would begin with known (or at least postulated) microscopic flow relations that hold on the “small” scale. These include continuum level conservation of mass, balance of species mass and momentum, conservation of energy, and a statement of the second law of thermodynamics often in the form of an entropy inequality (such as the Clausius-Duhem inequality). The averaged or macroscopic conservation equations and entropy inequalities are then obtained from the microscopic equations through suitable averaging procedures. At this stage a stronger form of the second law may also be postulated for the mixture of phases or materials. To render the evolutionary material flow balance system unique, constitutive equations and phase or material interaction relations are introduced from experimental observation, or by postulation, through strict enforcement of the constraints or restrictions resulting from the averaged entropy inequalities. These averaged equations form the governing equation system for the dynamic evolution of these mixture flows. Most commonly, the averaging technique utilized is either volume or time averaging or a combination of the two. The flow restrictions required for volume and time averaging to be valid can be severe, and violations of these restrictions are often found. A more general, less restrictive (and far less commonly used) type of averaging known

  13. Characterization of the multi-component driving land subsidence using Persistent Scatterer Interferometry technique: the Ravenna case of study (Italy)

    NASA Astrophysics Data System (ADS)

    Bonì, Roberta; Fiaschi, Simone; Calcaterra, Domenico; Di Martire, Diego; Ibrahim, Ahmed; Meisina, Claudia; Perini, Luisa; Ramondini, Massimo; Tessitore, Serena; Floris, Mario

    2015-04-01

    images acquired by ERS-1/2 (1992-2000), ENVISAT (2003-2010) and TERRASAR-X (2012-2014) sensors. The test site is located in the south-eastern sector of the Po River plain, along the Adriatic Sea, where there are present around 1500-3000 m of Quaternary deposits, mainly constituted by sandy and silty-clay layers of alluvial and marine origin. These sediments lay on a pre-Quaternary substratum characterized by buried active thrusts, which are parallel to the Apennine alignment. The particular geological context deserves special attention, because it hosts several municipalities and relevant infrastructures, where a long-trend of subsidence rate has been recorded over the last decades, representing the result of superimposed phenomena: tectonic, depositional, climatic and man-induced processes. The definition of the multi-component contribution is intended as a crucial step towards a more reliable subsidence prediction model, which, in turn, will help to better calibrate the suitable remedial measures as to prevent further ground deformations of this important coastal lowland.

  14. The HELLAS2XMM survey. XIII. Multi-component analysis of the spectral energy distribution of obscured AGN

    NASA Astrophysics Data System (ADS)

    Pozzi, F.; Vignali, C.; Comastri, A.; Bellocchi, E.; Fritz, J.; Gruppioni, C.; Mignoli, M.; Maiolino, R.; Pozzetti, L.; Brusa, M.; Fiore, F.; Zamorani, G.

    2010-07-01

    Aims: We combine near-to-mid-IR Spitzer data with shorter wavelength observations (optical to X-rays) to get insight into the properties of a sample of luminous, obscured active galactic nuclei (AGN). We aim at modelling their broad-band spectral energy distributions (SEDs) in order to estimate the main parameters related to the dusty torus that is assumed to be responsible for the reprocessed IR emission. Our final goal is to estimate the intrinsic nuclear luminosities and the Eddington ratios for our luminous, obscured AGN. Methods: The sample comprises 16 obscured high-redshift (0.9 ⪉ z ⪉ 2.1), X-ray luminous quasars (L2-10 keV ~ 1044 erg s-1) selected from the HELLAS2XMM survey in the 2-10 keV band. The optical-IR SEDs are described by a multi-component model that includes a stellar component to account for the optical and near-IR emission, an AGN component that dominates in the mid-IR (mainly emission from a dusty torus heated by nuclear radiation), and a starburst to reproduce the far-IR bump. A radiative transfer code to compute the spectrum and intensity of dust reprocessed emission was extensively tested against our multiwavelength data. While the torus parameters and the BH accretion luminosities are a direct output of the SED-fitting procedure, the BH masses were estimated indirectly by means of the local Mbulge-MBH relation. Results: The majority (~80%) of the sources show moderate optical depth (τ9.7 µm ≤ 3), and the derived column densities NH are consistent with the X-ray inferred values (1022 ⪉ NH ⪉ 3 × 1023 cm-2) for most of the objects, confirming that the sources are moderately obscured Compton-thin AGN. Accretion luminosities in the range 5 × 1044 ⪉ Lbol ⪉ 4 × 1046 erg s-1 are inferred from the multiwavelength fitting procedure. We compare model luminosities with those obtained by integrating the observed SED, finding that the latter are lower by a factor of ~2 in the median. The discrepancy can be as high as an order of

  15. Tunneling in degenerate atomic gases

    NASA Astrophysics Data System (ADS)

    Paraoanu, Gheorghe-Sorin

    The experimental achievement of Bose-Einstein condensation in cold alkali atomic gases in 1995 has started a period of fertile research at the intersection of atomic physics, quantum optics, and condensed matter. In this thesis, various tunneling effects in both bosonic and fermionic gases are investigated. The first part of this work deals with bosons in different Josephson-type experimental setups. After a brief general introduction we establish, in Chapter 2, a mapping between the phase and the Bogoliubov representation for the Josephson oscillations; in Chapter 3 we calculate the Josephson coupling constant for the condensate in the external Josephson effect. Chapter 4 deals with Josephson effects at the level of depletion: we describe in detail the oscillatory dynamics of the virtual quasiparticles. The next Chapter is a stability analysis for the formation of vortices in the Kibble Zurek scenario. Finally, Chapter 6 contains a discussion on the time-evolution of the many-body states in the absence of tunneling. The second part of the thesis (Chapter 7--Chapter 9) deals with fermionic systems below the BCS critical temperature. The first two of these Chapters explore the possibility of driving transitions between hyperfine states with lasers. In Chapter 7 we show that these transitions could be used to investigate the coherence of the Cooper pairs. In Chapter 8 we imagine an internal Josephson experiment which uses a pair of lasers to drive transitions between two superfluids. Finally, in Chapter 9 we examine the properties of vortices formed in trapped Cooper-paired fermionic gases.

  16. A System And Method To Determine Thermophysical Properties Of A Multi-Component Gas At Arbitrary Temperature And Pressure

    DOEpatents

    Morrow, Thomas E.; Behring, II, Kendricks A.

    2004-03-09

    A method to determine thermodynamic properties of a natural gas hydrocarbon, when the speed of sound in the gas is known at an arbitrary temperature and pressure. Thus, the known parameters are the sound speed, temperature, pressure, and concentrations of any dilute components of the gas. The method uses a set of reference gases and their calculated density and speed of sound values to estimate the density of the subject gas. Additional calculations can be made to estimate the molecular weight of the subject gas, which can then be used as the basis for mass flow calculations, to determine the speed of sound at standard pressure and temperature, and to determine various thermophysical characteristics of the gas.

  17. Photochemistry of biogenic gases

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.

    1989-01-01

    The relationship between the biosphere and the atmosphere is examined, emphasizing the composition and photochemistry and chemistry of the troposphere and stratosphere. The reactions of oxygen, ozone, and hydroxyl are reviewed and the fate of the biogenic gases ammonia, methane, reduced sulfur species, reduced halogen species, carbon monoxide, nitric oxide, nitrous oxide, nitrogen, and carbon dioxide are described. A list is given of the concentration and sources of the various gases.

  18. Quantum repeater with continuous variable encoding

    NASA Astrophysics Data System (ADS)

    Li, Linshu; Albert, Victor V.; Michael, Marios; Muralidharan, Sreraman; Zou, Changling; Jiang, Liang

    2016-05-01

    Quantum communication enables faithful quantum state transfer between different parties and protocols for cryptographic purposes. However, quantum communication over long distances (>1000km) remains challenging due to optical channel attenuation. This calls for investigation on developing novel encoding schemes that correct photon loss errors efficiently. In this talk, we introduce the generalization of multi-component Schrödinger cat states and propose to encode quantum information in these cat states for ultrafast quantum repeaters. We detail the quantum error correction procedures at each repeater station and characterize the performance of this novel encoding scheme given practical imperfections, such as coupling loss. A comparison with other quantum error correcting codes for bosonic modes will be discussed.

  19. Cooling Atomic Gases With Disorder

    NASA Astrophysics Data System (ADS)

    Scalettar, Richard

    Cold atomic gases have proven capable of emulating a number of fundamental condensed matter phenomena including Bose-Einstein condensation, the Mott transition, Fulde-Ferrell-Larkin-Ovchinnikov pairing and the quantum Hall effect. Cooling to a low enough temperature to explore magnetism and exotic superconductivity in lattices of fermionic atoms remains a challenge. We propose a method to produce a low temperature gas by preparing it in a disordered potential and following a constant entropy trajectory to deliver the gas into a non-disordered state which exhibits these incompletely understood phases. We show, using quantum Monte Carlo simulations, that we can approach the Neél temperature of the three-dimensional Hubbard model for experimentally achievable parameters. Recent experimental estimates suggest the randomness required lies in a regime where atom transport and equilibration are still robust. Thereza Paiva, Ehsan Khatami, Shuxiang Yang, Valery Rousseau, Mark Jarrell, Juana Moreno, Randall G. Hulet, and Richard T. Scalettar, arXiv:1508.02613 This work was supported by the NNSA SSAA program.

  20. High-Temperature Deformation Processing Map Approach for Obtaining the Desired Microstructure in a Multi-component (Ni-Ti-Cu-Fe) Alloy

    NASA Astrophysics Data System (ADS)

    Nayan, Niraj; Singh, Gaurav; Narayana Murty, S. V. S.; Jha, Abhay K.; Pant, Bhanu; George, Koshy M.

    2015-05-01

    An equiatomic NiTiCuFe multi-component alloy with simple body-centered cubic (bcc) and face-centered cubic solid-solution phases in the microstructure was processed by vacuum induction melting furnace under dynamic Ar atmosphere. High-temperature uniaxial compression experiments were conducted on it in the temperature range of 1073 K to 1303 K (800 °C to 1030 °C) and strain rate range of 10-3 to 10-1 s-1. The data generated were analyzed with the aid of the dynamic materials model through which power dissipation efficiency and instability maps were generated so as to identify the governing deformation mechanisms that are operative in different temperature-strain rate regimes with the aid of complementary microstructural analysis of the deformed specimens. Results indicate that the stable domain for the high temperature deformation of the multi-component alloy occurs in the temperature range of 1173 K to 1303 K (900 °C to 1030 °C) and range of 10-3 to 10-1.2 s-1, and the deformation is unstable at T = 1073 K to 1153 K (800 °C to 880 °C) and = 10-3 to 10-1.4 s-1 as well as T = 1223 K to 1293 K (950 °C to 1020 °C) and = 10-1.4 to 10-1 s-1, with adiabatic shear banding, localized plastic flow, or cracking being the unstable mechanisms. A constitutive equation that describes the flow stress of NiTiCuFe multi-component alloy as a function of strain rate and deformation temperature was also determined.

  1. Apparatus and method for maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling

    DOEpatents

    Felix, Larry Gordon; Farthing, William Earl; Irvin, James Hodges; Snyder, Todd Robert

    2010-05-11

    A dilution apparatus for diluting a gas sample. The apparatus includes a sample gas conduit having a sample gas inlet end and a diluted sample gas outlet end, and a sample gas flow restricting orifice disposed proximate the sample gas inlet end connected with the sample gas conduit and providing fluid communication between the exterior and the interior of the sample gas conduit. A diluted sample gas conduit is provided within the sample gas conduit having a mixing end with a mixing space inlet opening disposed proximate the sample gas inlet end, thereby forming an annular space between the sample gas conduit and the diluted sample gas conduit. The mixing end of the diluted sample gas conduit is disposed at a distance from the sample gas flow restricting orifice. A dilution gas source connected with the sample gas inlet end of the sample gas conduit is provided for introducing a dilution gas into the annular space, and a filter is provided for filtering the sample gas. The apparatus is particularly suited for diluting heated sample gases containing one or more condensable components.

  2. Study of Health and Activity in Preschool Environments (SHAPES): Study protocol for a randomized trial evaluating a multi-component physical activity intervention in preschool children

    PubMed Central

    2013-01-01

    Background Physical inactivity is a recognized public health concern. Inadequate proportions of children in the U.S, including those of preschool age, are meeting physical activity recommendations. In response to low numbers of preschool children attaining appropriate physical activity levels, combined with the large number of young children who attend preschool, researchers have identified the need to devise interventions to increase physical activity at preschools. However, few multi-component interventions to increase physical activity in preschool children exist. The aims of this study were to observe the effects of a multi-component intervention on physical activity, sedentary behavior, and physical activity energy expenditure in 3-5 year-old children; identify factors that associate with change in those variables; and evaluate the process of implementing the multi-component intervention. The purpose of this manuscript is to describe the study design and intervention protocol. Methods/design The overall design of the Study of Health and Activity in Preschool Environments (SHAPES) was a two-year randomized trial (nested cohort design), with two conditions, two measurement occasions, and preschool serving as the unit of analysis. Sixteen schools (eight intervention and eight control) were enrolled. The intervention protocol was based on the social ecological model and included four main components: (a) indoor physical activity (“move inside”), (b) recess (“move outside”), (c) daily lessons (“move to learn”), and (d) social environment. Components were implemented using teacher and administrator trainings and workshops, site support visits, newsletters, and self-monitoring methods. Outcomes included accelerometer assessment of physical activity, sedentary behavior, and physical activity energy expenditure; weight status; and demographic factors; family/home social and physical environment; and parental characteristics. An extensive process evaluation

  3. A multi-component nanocomposite screen-printed ink with non-linear touch sensitive electrical conductivity.

    PubMed

    Webb, Alexander J; Szablewski, Marek; Bloor, David; Atkinson, Del; Graham, Adam; Laughlin, Paul; Lussey, David

    2013-04-26

    Printable electronics is an innovative area of technology with great commercial potential. Here, a screen-printed functional ink, comprising a combination of semiconducting acicular particles, electrically insulating nanoparticles and a base polymer ink, is described that exhibits pronounced pressure sensitive electrical properties for applications in sensing and touch sensitive surfaces. The combination of these components in the as-printed ink yield a complex structure and a large and reproducible touch pressure sensitive resistance range. In contrast to the case for some composite systems, the resistance changes occur down to applied pressures of 13 Pa. Current-voltage measurements at fixed pressures show monotonic non-linear behaviour, which becomes more Ohmic at higher pressures and in all cases shows some hysteresis. The physical basis for conduction, particularly in the low pressure regime, can be described in terms of field assisted quantum mechanical tunnelling. PMID:23535342

  4. Physics of ultracold Fermi gases revealed by spectroscopies

    NASA Astrophysics Data System (ADS)

    Törmä, Päivi

    2016-04-01

    This article provides a brief review of how various spectroscopies have been used to investitage many-body quantum phenomena in the context of ultracold Fermi gases. In particular, work done with RF spectroscopy, Bragg spectroscopy and lattice modulation spectroscopy is considered. The theoretical basis of these spectroscopies, namely linear response theory in the many-body quantum physics context is briefly presented. Experiments related to the BCS-BEC crossover, imbalanced Fermi gases, polarons, possible pseudogap and Fermi liquid behaviour and measuring the contact are discussed. Remaining open problems and goals in the field are sketched from the perspective how spectroscopies could contribute.

  5. Planetary noble gases

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin

    1993-01-01

    An overview of the history and current status of research on planetary noble gases is presented. The discovery that neon and argon are vastly more abundant on Venus than on earth points to the solar wind rather than condensation as the fundamental process for placing noble gases in the atmospheres of the terrestrial planets; however, solar wind implantation may not be able to fully reproduce the observed gradient, nor does it obviously account for similar planetary Ne/Ar ratios and dissimilar planetary Ar/Kr ratios. More recent studies have emphasized escape rather than accretion. Hydrodynamic escape, which is fractionating, readily accounts for the difference between atmospheric neon and isotopically light mantle neon. Atmospheric cratering, which is nearly nonfractionating, can account for the extreme scarcity of nonradiogenic noble gases (and other volatiles) on Mars.

  6. Dependencies of multi-component T 2 and T 1 ρ relaxation on the anisotropy of collagen fibrils in bovine nasal cartilage

    NASA Astrophysics Data System (ADS)

    Wang, Nian; Xia, Yang

    2011-09-01

    Both NMR spectroscopy and MRI were used to investigate the dependencies of multi-component T2 and T1ρ relaxation on the anisotropy of bovine nasal cartilage (BNC). The non-negative least square (NNLS) method and the multi-exponential fitting method were used to analyze all experimental data. When the collagen fibrils in nasal cartilage were oriented at the magic angle (55°) to the magnetic field B 0, both T2 and T1ρ were single component, regardless of the spin-lock field strength or the echo spacing time in the pulse sequences. When the collagen fibrils in nasal cartilage were oriented at 0° to B 0, both T2 and T1ρ at a spin-lock field of 500 Hz had two components. When the spin-lock field was increased to 1000 Hz or higher, T1ρ relaxation in nasal cartilage became a single component, even when the specimen orientation was 0°. These results demonstrate that the specimen orientation must be considered for any multi-component analysis, even for nasal cartilage that is commonly considered homogenously structured. Since the rapidly and slowly relaxing components can be attributed to different portions of the water population in tissue, the ability to resolve different relaxation components could be used to quantitatively examine individual molecular components in connective tissues.

  7. The effectiveness of multi-component goal setting interventions for changing physical activity behaviour: a systematic review and meta-analysis.

    PubMed

    McEwan, Desmond; Harden, Samantha M; Zumbo, Bruno D; Sylvester, Benjamin D; Kaulius, Megan; Ruissen, Geralyn R; Dowd, A Justine; Beauchamp, Mark R

    2016-03-01

    Drawing from goal setting theory (Latham & Locke, 1991; Locke & Latham, 2002; Locke et al., 1981), the purpose of this study was to conduct a systematic review and meta-analysis of multi-component goal setting interventions for changing physical activity (PA) behaviour. A literature search returned 41,038 potential articles. Included studies consisted of controlled experimental trials wherein participants in the intervention conditions set PA goals and their PA behaviour was compared to participants in a control group who did not set goals. A meta-analysis was ultimately carried out across 45 articles (comprising 52 interventions, 126 effect sizes, n = 5912) that met eligibility criteria using a random-effects model. Overall, a medium, positive effect (Cohen's d(SE) = .552(.06), 95% CI = .43-.67, Z = 9.03, p < .001) of goal setting interventions in relation to PA behaviour was found. Moderator analyses across 20 variables revealed several noteworthy results with regard to features of the study, sample characteristics, PA goal content, and additional goal-related behaviour change techniques. In conclusion, multi-component goal setting interventions represent an effective method of fostering PA across a diverse range of populations and settings. Implications for effective goal setting interventions are discussed. PMID:26445201

  8. Effectiveness of a Worksite Mindfulness-Related Multi-Component Health Promotion Intervention on Work Engagement and Mental Health: Results of a Randomized Controlled Trial

    PubMed Central

    van Berkel, Jantien; Boot, Cécile R. L.; Proper, Karin I.; Bongers, Paulien M.; van der Beek, Allard J.

    2014-01-01

    Objectives The aim of the present study was to evaluate the effectiveness of a worksite mindfulness-related multi-component health promotion intervention on work engagement, mental health, need for recovery and mindfulness. Methods In a randomized controlled trial design, 257 workers of two research institutes participated. The intervention group (n = 129) received a targeted mindfulness-related training, followed by e-coaching. The total duration of the intervention was 6 months. Data on work engagement, mental health, need for recovery and mindfulness were collected using questionnaires at baseline and after 6 and 12 months follow-up. Effects were analyzed using linear mixed effect models. Results There were no significant differences in work engagement, mental health, need for recovery and mindfulness between the intervention and control group after either 6- or 12-months follow-up. Additional analyses in mindfulness-related training compliance subgroups (high and low compliance versus the control group as a reference) and subgroups based on baseline work engagement scores showed no significant differences either. Conclusions This study did not show an effect of this worksite mindfulness-related multi-component health promotion intervention on work engagement, mental health, need for recovery and mindfulness after 6 and 12 months. Trial registration Netherlands Trial Register NTR2199 PMID:24489648

  9. [Study on quality control of Houttuynia Cordata, a traditional Chinese medicine by fingerprint combined with quantitative analysis of multi-components by single marker].

    PubMed

    He, Bing; Liu, Yan; Tian, Ji; Li, Chun-Hong; Yang, Shi-Yan

    2013-08-01

    To establish a new method of quality evaluation of Traditional Chinese medicine by fingerprint and quantitative analysis of multi-components by single marker method (QAMS). The quality evaluation method was established and validated with Houttuyniae Herba. Chlorogcnic acid was selected as markers of ingredients to establish HPLC fingerprint and internal reference standard to determine the contents of other 6 components (new chlorogcnic acid, cryptochlorogenic acid, rutin, hyperin, isoquercitrin, quercitrin) according to the relative correction factor. At the same time, the seven components were determined by external standard method. The accuracy and feasibility of QAMS was evaluated by comparison of the results between external standard method and QAMS. All tested samples contained the 12 common peaks , 7 of which was verified ,and there was no significant differences between the quantitative results of 7 ingredients of multi-components by single marker method and external standard method in 20 batches. The method of fingerprint combined with QAMS has been verified in Houttuyniae Herba and it is to be a new quality evaluation pattern for Traditional Chinese medicine. PMID:24228587

  10. Applications of quantum cascade lasers in plasma diagnostics: a review

    NASA Astrophysics Data System (ADS)

    Röpcke, J.; Davies, P. B.; Lang, N.; Rousseau, A.; Welzel, S.

    2012-10-01

    Over the past few years mid-infrared absorption spectroscopy based on quantum cascade lasers operating over the region from 3 to 12 µm and called quantum cascade laser absorption spectroscopy or QCLAS has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry of molecular plasmas. The increasing interest in processing plasmas containing hydrocarbons, fluorocarbons, nitrogen oxides and organo-silicon compounds has led to further applications of QCLAS because most of these compounds and their decomposition products are infrared active. QCLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species at time resolutions below a microsecond, which is of particular importance for the investigation of reaction kinetics and dynamics. Information about gas temperature and population densities can also be derived from QCLAS measurements. Since plasmas with molecular feed gases are used in many applications such as thin film deposition, semiconductor processing, surface activation and cleaning, and materials and waste treatment, this has stimulated the adaptation of QCLAS techniques to industrial requirements including the development of new diagnostic equipment. The recent availability of external cavity (EC) QCLs offers a further new option for multi-component detection. The aim of this paper is fourfold: (i) to briefly review spectroscopic issues arising from applying pulsed QCLs, (ii) to report on recent achievements in our understanding of molecular phenomena in plasmas and at surfaces, (iii) to describe the current status of industrial process monitoring in the mid-infrared and (iv) to discuss the potential of advanced instrumentation based on EC-QCLs for plasma diagnostics.

  11. Gases in Tektite Bubbles.

    PubMed

    O'keefe, J A; Lowman, P D; Dunning, K L

    1962-07-20

    Spectroscopic analysis of light produced by electrodeless discharge in a tektite bubble showed the main gases in the bubble to be neon, helium, and oxygen. The neon and helium have probably diffused in from the atmosphere, while the oxygen may be atmospheric gas incorporated in the tektite during its formation. PMID:17801113

  12. Progress towards ultracold gases in arbitrary 2D potentials

    NASA Astrophysics Data System (ADS)

    Corcovilos, Theodore

    2016-05-01

    We describe our progress in building an apparatus for investigating degenerate quantum gases of potassium in arbitrary two-dimensional optical potentials. The optical potentials are created by holographic projection of an image created using a MEMS mirror array. Systems we would like to study with this experiment are quantum simulations of bosons and fermions at crystal heterojunctions and systems with well defined boundaries, including topological edge states. Funding provided by the Charles E Kaufman Foundation, a part of the Pittsburgh Foundation.

  13. Theoretical Assessment on the Phase Transformation Kinetic Pathways of Multi-component Ti Alloys: Application to Ti-6Al-4V

    DOE PAGESBeta

    Ji, Yanzhou; Heo, Tae Wook; Zhang, Fan; Chen, Long-Qing

    2015-12-21

    Here we present our theoretical assessment of the kinetic pathways during phase transformations of multi-component Ti alloys. Employing the graphical thermodynamic approach and an integrated free energy function based on the realistic thermodynamic database and assuming that a displacive structural transformation occurs much faster than long-range diffusional processes, we analyze the phase stabilities of Ti-6Al-4V (Ti-6wt.%Al-4wt.%V). Our systematic analyses predict a variety of possible kinetic pathways for β to (α + β) transformations leading to different types of microstructures under various heat treatment conditions. In addition, the possibility of unconventional kinetic pathways is discussed. Lastly, we also briefly discuss themore » application of our approach to general multicomponent/multiphase alloy systems.« less

  14. Unconditionally energy stable time stepping scheme for Cahn-Morral equation: Application to multi-component spinodal decomposition and optimal space tiling

    NASA Astrophysics Data System (ADS)

    Tavakoli, Rouhollah

    2016-01-01

    An unconditionally energy stable time stepping scheme is introduced to solve Cahn-Morral-like equations in the present study. It is constructed based on the combination of David Eyre's time stepping scheme and Schur complement approach. Although the presented method is general and independent of the choice of homogeneous free energy density function term, logarithmic and polynomial energy functions are specifically considered in this paper. The method is applied to study the spinodal decomposition in multi-component systems and optimal space tiling problems. A penalization strategy is developed, in the case of later problem, to avoid trivial solutions. Extensive numerical experiments demonstrate the success and performance of the presented method. According to the numerical results, the method is convergent and energy stable, independent of the choice of time stepsize. Its MATLAB implementation is included in the appendix for the numerical evaluation of algorithm and reproduction of the presented results.

  15. Theoretical Assessment on the Phase Transformation Kinetic Pathways of Multi-component Ti Alloys: Application to Ti-6Al-4V

    SciTech Connect

    Ji, Yanzhou; Heo, Tae Wook; Zhang, Fan; Chen, Long-Qing

    2015-12-21

    Here we present our theoretical assessment of the kinetic pathways during phase transformations of multi-component Ti alloys. Employing the graphical thermodynamic approach and an integrated free energy function based on the realistic thermodynamic database and assuming that a displacive structural transformation occurs much faster than long-range diffusional processes, we analyze the phase stabilities of Ti-6Al-4V (Ti-6wt.%Al-4wt.%V). Our systematic analyses predict a variety of possible kinetic pathways for β to (α + β) transformations leading to different types of microstructures under various heat treatment conditions. In addition, the possibility of unconventional kinetic pathways is discussed. Lastly, we also briefly discuss the application of our approach to general multicomponent/multiphase alloy systems.

  16. Determination and quality evaluation of green tea extracts through qualitative and quantitative analysis of multi-components by single marker (QAMS).

    PubMed

    Li, Da-Wei; Zhu, Ming; Shao, Yun-Dong; Shen, Zhe; Weng, Chen-Chen; Yan, Wei-Dong

    2016-04-15

    The quality of tea is mainly attributed to tea polyphenols and caffeine. In this paper, a new strategy for quality evaluation of green tea extracts was explored and verified through qualitative and quantitative analysis of multi-components by single marker (QAMS). Taguchi Design was introduced to evaluate the fluctuations of the relative conversion factors (fx) of tea catechins, gallic acid and caffeine to epigallocatechin gallate. The regression model (Sig.=0.000) and the deviations (R(2)>0.999) between QAMS and normal external standard method proved the consistency of the two methods. Hierarchical cluster analysis and canonical discriminant analysis were employed to classify 26 batches of commercial Longjing green tea extracts (LJGTEs) collected from different producers. The results showed a significant difference in component profile between the samples from different origins. The QAMS method was verified to be an alternative and promising method to comprehensively and effectively control the quality of LJGTEs from different origins. PMID:26675847

  17. Radar Imaging of Non-Uniformly Rotating Targets via a Novel Approach for Multi-Component AM-FM Signal Parameter Estimation

    PubMed Central

    Wang, Yong

    2015-01-01

    A novel radar imaging approach for non-uniformly rotating targets is proposed in this study. It is assumed that the maneuverability of the non-cooperative target is severe, and the received signal in a range cell can be modeled as multi-component amplitude-modulated and frequency-modulated (AM-FM) signals after motion compensation. Then, the modified version of Chirplet decomposition (MCD) based on the integrated high order ambiguity function (IHAF) is presented for the parameter estimation of AM-FM signals, and the corresponding high quality instantaneous ISAR images can be obtained from the estimated parameters. Compared with the MCD algorithm based on the generalized cubic phase function (GCPF) in the authors’ previous paper, the novel algorithm presented in this paper is more accurate and efficient, and the results with simulated and real data demonstrate the superiority of the proposed method. PMID:25806870

  18. Analysis of localization phenomena in weakly interacting disordered lattice gases

    NASA Astrophysics Data System (ADS)

    Schulte, T.; Drenkelforth, S.; Kruse, J.; Tiemeyer, R.; Sacha, K.; Zakrzewski, J.; Lewenstein, M.; Ertmer, W.; Arlt, J. J.

    2006-10-01

    Disorder plays a crucial role in many systems particularly in solid state physics. However, the disorder in a particular system cannot usually be chosen or controlled. We show that the unique control available for ultracold atomic gases may be used for the production and observation of disordered quantum degenerate gases. A detailed analysis of localization effects for two possible realizations of a disordered potential is presented. In a theoretical analysis, clear localization effects are observed when a superlattice is used to provide a quasiperiodic disorder. The effects of localization are analysed by investigating the superfluid fraction and the localization length within the system. The theoretical analysis in this paper paves a clear path for the future observation of Anderson-like localization in disordered quantum gases.

  19. Benefits of using multi-component transmitter-receiver systems for determining geometrical parameters of a dipole conductor from single-line anomalies

    NASA Astrophysics Data System (ADS)

    Desmarais, Jacques K.; Smith, Richard S.

    2016-03-01

    We show the advantages of using multi-component transmitter-receiver systems for determining the geometry of a compact planar target whose electromagnetic response can be approximated by a dipole. Our approach is based on a modified version of an algorithm that we previously published using a single-component (vertical) transmitter. Tests on synthetic models reveal that single transmitter systems are unable to resolve the orientation of a dipole conductor that approaches axial symmetry with respect to the traverse line. This occurs as a result of lack of a noticeable y-component anomaly, where the y-component is oriented transverse to the flight-line direction. For a plate-like conductor, axial symmetry equates to being at a small offset and having a strike parallel or perpendicular to the traverse line. Here, the term `offset' is used to denote the lateral distance from the centre of the conductor to the flight line. The ambiguities can be resolved through measuring specific components of a multi-component transmitter-receiver system; namely, Rxz and Rzz with one of Rxy, Ryy, Rzy, Ryx and Ryz, where the first letter denotes the orientation of the transmitter and the second letter denotes the orientation of the receiver. However, for the case of a MEGATEM system geometry, measuring Rzx, Rzz and Ryx is most suitable for determining the geometry of conductors striking nearly perpendicular or parallel, and at small offset to the traverse line. The minimum system capable of determining the correct geometrical parameters of a dipole conductor for the small-offset symmetric case would therefore consist of a two-component (y- and z-directed) transmitter, as well as a two component (x- and z-directed) receiver. Tests on line 15701 of the MEGATEM survey in Chibougamau, Quebec, confirm the inability of single-transmitter systems to determine geometrical parameters of a dipole conductor for the case where y-component data is unavailable.

  20. Cation non-stoichiometry in multi-component oxide nanoparticles by solution chemistry: a case study on CaWO4 for tailored structural properties.

    PubMed

    Hu, Wanbiao; Tong, Wenming; Li, Liping; Zheng, Jing; Li, Guangshe

    2011-06-28

    Chemical composition directly determines the structure and properties of almost all bulk inorganic solids, which are however popularly dismissed in the literature as a cause of property changes when studying multi-component oxide nanostructures by solution chemistries. The current work focuses on this subject through a systematic case study on CaWO(4) nanocrystals. CaWO(4) nanocrystals were prepared using room-temperature solution chemistry, in which a capping agent of citric acid was employed for kinetic grain size control. Sample characterizations by a set of techniques indicated that 5-7 nm CaWO(4) was obtained at room temperature, showing a pure-phase of tetrahedral scheelite structure. The molar ratio of Ca(2+) to W(6+) was found to be 1.2:1, apparently deviating from the unity expected for the stoichiometric CaWO(4). Such nonstoichiometry was further modulated via iso-valent incorporation of smaller Zn(2+) to the Ca(2+)-sites in CaWO(4). It is found that with increasing the Zn(2+) content, there appeared transformation from high to low nonstoichiometry, though a pure scheelite-typed structure was retained. Such a nonstoichiometry was primarily represented by excessive cations like Zn(2+) and/or Ca(2+) within the surface disorder layers, which in turn showed a great impact on the structure and properties as demonstrated by a lattice contraction, band-gap narrowing, luminescence quenching, as well as improved conductivity. The property changes were rationalized in terms of surface structural disorder, electro-negativity discrepancy, and effective activation on the mobile protons. Consequently, systematic control over the non-stoichiometry for single-phase multi-component oxide nanostructures by solution chemistry is proven fundamentally important, which may help to achieve quantitatively the structure-property relationship for materials design and performance optimization. PMID:21556429

  1. Proposal of AAA-battery-size one-shot ATR Fourier spectroscopic imager for on-site analysis: Simultaneous measurement of multi-components with high accuracy

    NASA Astrophysics Data System (ADS)

    Hosono, Satsuki; Qi, Wei; Sato, Shun; Suzuki, Yo; Fujiwara, Masaru; Hiramatsu, Hiroyuki; Suzuki, Satoru; Abeygunawardhana, P. K. W.; Wada, Kenji; Nishiyama, Akira; Ishimaru, Ichiro

    2015-03-01

    For simultaneous measurement of multi-components on-site like factories, the ultra-compact (diameter: 9[mm], length: 45[mm], weight: 200[g]) one-shot ATR (Attenuated Total Reflection) Fourier spectroscopic imager was proposed. Because the proposed one-shot Fourier spectroscopic imaging is based on spatial-phase-shift interferometer, interferograms could be obtained with simple optical configurations. We introduced the transmission-type relativeinclined phase-shifter, that was constructed with a cuboid prism and a wedge prism, onto the optical Fourier transform plane of infinity corrected optical systems. And also, small light-sources and cameras in the mid-infrared light region, whose size are several millimeter on a side, are essential components for the ultra-compact spectroscopic configuration. We selected the Graphite light source (light source area: 1.7×1.7[mm], maker: Hawkeye technologies) whose radiation factor was high. Fortunately, in these days we could apply the cost-effective 2-dimensional light receiving device for smartphone (e.g. product name: LEPTON, maker: FLIR, price: around 400USD). In the case of alcoholic drinks factory, conventionally workers measure glucose and ethanol concentrations by bringing liquid solution back to laboratories every day. The high portable spectroscopy will make it possible to measure multi-components simultaneously on manufacturing scene. But we found experimentally that absorption spectrum of glucose and water and ethanol were overlapped each other in near infrared light region. But for mid-infrared light region, we could distinguish specific absorption peaks of glucose (@10.5[μm]) and ethanol (@11.5[μm]) independently from water absorption. We obtained standard curve between absorption (@9.6[μm]) and ethanol concentration with high correlation coefficient 0.98 successfully by ATR imaging-type 2-dimensional Fourier spectroscopy (wavelength resolution: 0.057[μm]) with the graphite light source (maker: Hawkeye

  2. Atomtronics with Ultracold Bose Gases

    NASA Astrophysics Data System (ADS)

    Ott, Herwig

    Neutral atom systems can exhibit similar transport properties like solid state devices. For instance, a neutral atom current is induced by a difference in chemical potential very much in the same way as a voltage drives an electric current. Employing Bose-Einstein condensed atomic gases allows observing superfluid transport phenomena, thus drawing connections to superconductivity. With help of light fields, the atomic current can additionally be guided in engineered potential landscapes in which one can also incorporate tunneling junctions. Eventually, the different components and elements can be integrated in atomtronic circuits which shed light on fundamental transport properties of many-body quantum systems. In this talk, I will present two fundamental atomtronic devices. The first is the observation of negative differential conductivity, which occurs at a multimode tunneling junction for ultracold atoms. The second is the appearance of a DC Josephson current in a biased tunneling junction, which features bistable transport characteristics. I will discuss the prospects of these basic elements for more complex atomtronic circuits.

  3. Numerical computation for teaching quantum statistics

    NASA Astrophysics Data System (ADS)

    Price, Tyson; Swendsen, Robert H.

    2013-11-01

    The study of ideal quantum gases reveals surprising quantum effects that can be observed in macroscopic systems. The properties of bosons are particularly unusual because a macroscopic number of particles can occupy a single quantum state. We describe a computational approach that supplements the usual analytic derivations applicable in the thermodynamic limit. The approach involves directly summing over the quantum states for finite systems and avoids the need for doing difficult integrals. The results display the unusual behavior of quantum gases even for relatively small systems.

  4. Initial Melting and wall-rock flux-melting of a wet multi-component mantle and its implications for the formation of MORB

    NASA Astrophysics Data System (ADS)

    Morgan, J. P.; Hasenclever, J.

    2013-12-01

    We explore several simple scenarios for wet melting of a heterogeneous multi- component mantle. In our melting formulation the mantle is viewed as a mixture consisting of a heterogeneously depleted peridotite matrix with embedded veins of fertile peridotite and/or geochemically enriched pyroxenite. These lithological units differ in their mineral composition but are assumed to have diffusively equilibrated both their water/hydrogen content and temperature over the hundreds of millions to billions of years prior to entering a melting region. During the melting process, however, only thermal but not chemical (water) equilibrium is assumed between the lithologies, which is a reasonable assumption for veins with thicknesses on the order of few tens to few hundreds of meters, a thermal diffusivity of 10^-6 m^2/s and a diffusivity of hydrogen of less than 3*10^-9 m^2/s. The thermodynamic formulation of the multi-component melting process, during which all components have to share thermal energy, is based on Phipps Morgan (2001). The wet melting parameterization by Katz et al. (2003) has been included in the thermodynamic formulation by modifying its solidus-depletion-dependence and treating water partitioning during melting as partitioning of a trace element with a D-value like that of Ce. Usually, fractional melting with a small trapped melt fraction is assumed. We will mostly discuss results from 1-D model calculations, which represent the idealized decompression of a multi-component mantle rising underneath a mid-ocean ridge. Melt-migration is assumed to occur as vertical ascent within each column. We have also extended the formulation to examine the effects of rising melts on 'flux-melting' the wall-rock through which they migrate. We are still testing to see if this mechanism can be the reason why ridge melts almost always have major element chemistries in equilibrium with a peridotitic mantle, while the incompatible trace elements in EMORB reflect the influence of

  5. Long distance quantum communication using continuous variable encoding

    NASA Astrophysics Data System (ADS)

    Li, Linshu; Albert, Victor; Michael, Marios; Muralidharan, Sreraman; Zou, Changling; Jiang, Liang

    Quantum communication enables faithful quantum state transfer between different parties and protocols for cryptographic purposes. However, quantum communication over long distances (>1000km) remains challenging due to optical channel attenuation. This calls for investigation on developing novel encoding schemes that correct photon loss errors efficiently. In this talk, we introduce the generalization of multi-component Schrödinger cat states and propose to encode quantum information in these cat states for ultrafast quantum repeaters. We detail the quantum error correction procedures at each repeater station and characterize the performance of this novel encoding scheme given practical imperfections, such as coupling loss. A comparison with other quantum error correcting codes for bosonic modes will be discussed.

  6. A systematic study on the influencing parameters and improvement of quantitative analysis of multi-component with single marker method using notoginseng as research subject.

    PubMed

    Wang, Chao-Qun; Jia, Xiu-Hong; Zhu, Shu; Komatsu, Katsuko; Wang, Xuan; Cai, Shao-Qing

    2015-03-01

    A new quantitative analysis of multi-component with single marker (QAMS) method for 11 saponins (ginsenosides Rg1, Rb1, Rg2, Rh1, Rf, Re and Rd; notoginsenosides R1, R4, Fa and K) in notoginseng was established, when 6 of these saponins were individually used as internal referring substances to investigate the influences of chemical structure, concentrations of quantitative components, and purities of the standard substances on the accuracy of the QAMS method. The results showed that the concentration of the analyte in sample solution was the major influencing parameter, whereas the other parameters had minimal influence on the accuracy of the QAMS method. A new method for calculating the relative correction factors by linear regression was established (linear regression method), which demonstrated to decrease standard method differences of the QAMS method from 1.20%±0.02% - 23.29%±3.23% to 0.10%±0.09% - 8.84%±2.85% in comparison with the previous method. And the differences between external standard method and the QAMS method using relative correction factors calculated by linear regression method were below 5% in the quantitative determination of Rg1, Re, R1, Rd and Fa in 24 notoginseng samples and Rb1 in 21 notoginseng samples. And the differences were mostly below 10% in the quantitative determination of Rf, Rg2, R4 and N-K (the differences of these 4 constituents bigger because their contents lower) in all the 24 notoginseng samples. The results indicated that the contents assayed by the new QAMS method could be considered as accurate as those assayed by external standard method. In addition, a method for determining applicable concentration ranges of the quantitative components assayed by QAMS method was established for the first time, which could ensure its high accuracy and could be applied to QAMS methods of other TCMs. The present study demonstrated the practicability of the application of the QAMS method for the quantitative analysis of multi-component

  7. Multiple Geophysical Observations by a newly developed multi-component borehole instrument at the Continental Deep Drilling Site of the CCSD, Donghai, China

    NASA Astrophysics Data System (ADS)

    Xu, J.; Zhao, Z.; Ishii, H.; Yamauchi, T.

    2004-12-01

    Multiple Geophysical Observations by a newly developed multi-component borehole instrument at the Continental Deep Drilling Site of the CCSD, Donghai, China Jiren Xu1 (+86-10-68992879; xujiren@ccsd.org.cn) Zhixin Zhao1 (+86-10-68999734; zhaozhixin@ccsd.org.cn) Hiroshi Ishii2 (+81-0572-67-3105; ishii@tries.gr.jp Tsuneo Yamauchi3 (+81-052-789-3045; yamauchi@seis.nagoya-u.ac.jp) 1 Institute of Geology, Chinese Academy of Geological Sciences, China 2 Tono Research Institute of Earthquake Science (TRIES), Japan 3 Graduate School of Environmental Studies, Nagoya University, Japan The Chinese Continental Scientific Drilling (CCSD) site is located in the Donghai area of the Dabie-Sulu belt, which is the largest UHPM belt in the world. The drilling of the main borehole with 5000m will finish in next year. Three satellite boreholes, PP1, PP2 and PP3 were drilled and various surveys have been performed in the Donghai area about 6 years ago. We are going to install a newly developed Multi-component Instrument for borehole observations in main hole near the large Tanlu fault, and establish a long-term underground observation laboratory, which is the first noiseless one in China. The seismic activity and various geophysical fields, viz. strain, geomagnetism, geothermy, tilt, pore pressure etc. will be investigated. Data from the underground laboratory will be open to scientific, engineering and public services. We will measure the initial stress in various depths of the borehole by overcoring method using a new developed wireless intelligent type strainmeter of in-situ stress. Establishing a long-term noiseless underground observation laboratory at deep borehole and investigating crustal movement in East China are important for observing the physical conditions of the earth¡_s interior and solving many social problems, such as resources, disasters and environment. Multiple geophysical observations and the study in deep borehole will speed up and develop the study on tectonics

  8. Quantitative planar laser-induced fluorescence imaging of multi-component fuel/air mixing in a firing gasoline-direct-injection engine: Effects of residual exhaust gas on quantitative PLIF

    SciTech Connect

    Williams, Ben; Ewart, Paul; Wang, Xiaowei; Stone, Richard; Ma, Hongrui; Walmsley, Harold; Cracknell, Roger; Stevens, Robert; Richardson, David; Fu, Huiyu; Wallace, Stan

    2010-10-15

    A study of in-cylinder fuel-air mixing distributions in a firing gasoline-direct-injection engine is reported using planar laser-induced fluorescence (PLIF) imaging. A multi-component fuel synthesised from three pairs of components chosen to simulate light, medium and heavy fractions was seeded with one of three tracers, each chosen to co-evaporate with and thus follow one of the fractions, in order to account for differential volatility of such components in typical gasoline fuels. In order to make quantitative measurements of fuel-air ratio from PLIF images, initial calibration was by recording PLIF images of homogeneous fuel-air mixtures under similar conditions of in-cylinder temperature and pressure using a re-circulation loop and a motored engine. This calibration method was found to be affected by two significant factors. Firstly, calibration was affected by variation of signal collection efficiency arising from build-up of absorbing deposits on the windows during firing cycles, which are not present under motored conditions. Secondly, the effects of residual exhaust gas present in the firing engine were not accounted for using a calibration loop with a motored engine. In order to account for these factors a novel method of PLIF calibration is presented whereby 'bookend' calibration measurements for each tracer separately are performed under firing conditions, utilising injection into a large upstream heated plenum to promote the formation of homogeneous in-cylinder mixtures. These calibration datasets contain sufficient information to not only characterise the quantum efficiency of each tracer during a typical engine cycle, but also monitor imaging efficiency, and, importantly, account for the impact of exhaust gas residuals (EGR). By use of this method EGR is identified as a significant factor in quantitative PLIF for fuel mixing diagnostics in firing engines. The effects of cyclic variation in fuel concentration on burn rate are analysed for different

  9. Investigation of warm-cloud microphysics using a multi-component cloud model: Interactive effects of the aerosol spectrum. Master's thesis

    SciTech Connect

    Zahn, S.G.

    1993-12-01

    Clouds, especially low, warm, boundary-layer clouds, play an important role in regulating the earth's climate due to their significant contribution to the global albedo. The radiative effects of individual clouds are controlled largely by cloud microstructure, which is itself sensitive to the concentration and spectral distribution of the atmospheric aerosol. Increases in aerosol particle concentrations from anthropogenic activity could result in increased cloud albedo and global cloudiness, increasing the amount of reflected solar radiation. However, the effects of increased aerosol particle concentrations could be offset by the presence of giant or ultragiant aerosol particles. A one-dimensional, multi-component microphysical cloud model has been used to demonstrate the effects of aerosol particle spectral variations on the microstructure of warm clouds. Simulations performed with this model demonstrate that the introduction of increased concentrations of giant aerosol particles has a destabilizing effect on the cloud microstructure. Also, it is shown that warm-cloud microphysical processes modify the aerosol particle spectrum, favoring the generation of the largest sized particles via the collision-coalescence process. These simulations provide further evidence that the effect of aerosol particles on cloud microstructure must be addressed when considering global climate forecasts.

  10. The Mechanical and Corrosion Behaviors of As-cast and Re-melted AlCrCuFeMnNi Multi-Component High-Entropy Alloy

    NASA Astrophysics Data System (ADS)

    Soare, Vasile; Mitrica, Dumitru; Constantin, Ionut; Popescu, Gabriela; Csaki, Ioana; Tarcolea, Mihai; Carcea, Ioan

    2015-04-01

    A multi-component AlCrCuFeMnNi high-entropy alloy, prepared by vacuum induction melting, was investigated for structural, mechanical, and corrosion characteristics, before and after the re-melting process. Optical microscopy analysis revealed a dendritic solidification behavior. The interdendritic area contains two main phases and occasionally small hard phases. The re-melting process produced a finer dendritic structure, with rounded dendrites and reduced interdendritic hard phases. The SEM-EDAX analysis showed that the dendrite region contains a Widmanstatten type of structure and are composed of Cr-Fe rich phases, whereas the interdendrite region contains Cu and Mn rich phases. XRD analysis revealed two disordered BCC type A2 structures with high Cr and Fe content and an FCC A12 type of structure for the Cu and Mn rich interdendritic phase. The lattice constants, determined by X-ray diffraction, are 2.87 and 2.91 Å for the A2 phases and 3.67 Å for A1 phase. The Vickers micro hardness increased with the homogeneity of the alloy, having a maximum value of 4370 MPa for the re-melted sample. Corrosion tests carried out in 3.5 wt pct sodium chloride aerated solution indicated that the corrosion resistance improved with the re-melting process, being 1.5 to 2 times better than that of 304 stainless steel.

  11. Influence of ionic strength changes on the structure of pre-adsorbed salivary films. A response of a natural multi-component layer.

    PubMed

    Macakova, Lubica; Yakubov, Gleb E; Plunkett, Mark A; Stokes, Jason R

    2010-05-01

    Salivary films coating oral surfaces are critically important for oral health. This study focuses on determining the underlying nature of this adsorbed film and how it responds to departures from physiological conditions due to changes in ionic strength. Under physiological conditions, it is found that pre-adsorbed in vitro salivary film on hydrophobic surfaces is present as a highly hydrated viscoelastic layer. We follow the evolution of this film in terms of its effective thickness, hydration and viscoelastic properties, as well as adsorbed mass of proteins, using complementary surface characterisation methods: a Surface Plasmon Resonance (SPR) and a Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D). Our results support a heterogeneous model for the structure of the salivary film with an inner dense anchoring layer and an outer highly extended hydrated layer. Further swelling of the film was observed upon decreasing the salt concentration down to 1mM NaCl. However, upon exposure to deionised water, a collapse of the film occurs that was associated with the loss of water contained within the adsorbed layer. We suggest that the collapse in deionised water is driven by an onset of electrostatic attraction between different parts of the multi-component salivary film. It is anticipated that such changes could also occur when the oral cavity is exposed to food, beverage, oral care and pharmaceutical formulations where drastic changes to the structural integrity of the film is likely to have implications on oral health, sensory perception and product performance. PMID:20133111

  12. Nonthermal and positron effects on the dust acoustic surface wave in a semi-bounded multi-component Lorentzian dusty plasma

    NASA Astrophysics Data System (ADS)

    Lee, Myoung-Jae; Jung, Young-Dae

    2015-09-01

    Nonthermal and positron effects on the dust acoustic surface waves propagating at the interface between a multi-component Lorentzian dusty plasma and a vacuum are investigated. The dispersion relation is kinetically derived by employing the specular reflection boundary condition and the dielectric permittivity for dusty plasma containing positrons. We found that there exist two modes of the dust acoustic surface wave; high- and low-frequency modes. We observe that both H- and L-modes are enhanced by the increase of the pair annihilation rate. However, the effects of positron density are duplex depending on the ratio of annihilated positrons. The effects of nonthermal plasmas are also investigated on the H- and L-modes of dust acoustic surface waves. We found that the nonthermal plasmas suppress the frequencies both H- and L-modes. This research was supported by Nuclear Fusion Research Program through NRF funded by the Ministry of Science, ICT & Future Planning (Grant No. 2015M1A7A1A01002786).

  13. Furnace Cyclic Behavior of Plasma-Sprayed Zirconia-Yttria and Multi-Component Rare Earth Oxide Doped Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Nesbitt, James A.; McCue, Terry R.; Barrett, Charles A.; Miller, Robert A.

    2002-01-01

    Ceramic thermal barrier coatings will play an increasingly important role in advanced gas turbine engines because of their ability to enable further increases in engine temperatures. However, the coating performance and durability become a major concern under the increasingly harsh thermal cycling conditions. Advanced zirconia- and hafnia-based cluster oxide thermal barrier coatings with lower thermal conductivity and improved thermal stability are being developed using a high-heat-flux laser-rig based test approach. Although the new composition coatings were not yet optimized for cyclic durability, an initial durability screening of numerous candidate coating materials was carried out using conventional furnace cyclic tests. In this paper, furnace thermal cyclic behavior of the advanced plasma-sprayed zirconia-yttria-based thermal barrier coatings that were co-doped with multi-component rare earth oxides was investigated at 1163 C using 45 min hot cycles. The ceramic coating failure mechanisms were studied by using scanning electron microscopy combined with X-ray diffraction phase analysis after the furnace tests. The coating cyclic lifetime will be discussed in relation to coating phase structures, total dopant concentrations, and other properties.

  14. Multi-component molecular orbital study on positron attachment to alkali-metal hydride molecules: nature of chemical bonding and dissociation limits of [LiH; e+

    NASA Astrophysics Data System (ADS)

    Oyamada, Takayuki; Tachikawa, Masanori

    2014-08-01

    We have performed multi-component full-configuration interaction calculations to investigate the nature of chemical bonding of [LiH;e+] at the small and large internuclear distance. We discuss the importance of geometrical changes in positronic compounds induced by a positron attachment in terms of the virial theorem, with a comparison of the adiabatic- and vertical-positron affinity (PA). The systematic improvement of the PA values achieved by optimisation of (i) the molecular geometry and (ii) the positronic basis centre is also discussed. The stable dissociation channel of [LiH;e+] is compared with the ionic- and neutral-dissociation channels of its parent molecule LiH through the analysis of the potential energy curve and the electronic and positronic densities. The vertical PA as a function of is also presented, which is the difference between the potential energy curve of the parent molecule (LiH → Li + H) and its positronic compound ([LiH; e+] → Li + [H; e+]). Unlike the preceding study of [M. Mella et al., J. Chem. Phys. 113, 6154 (2000)], it took more than bohr to converge the vertical PA due to the long-range ionic bonding interaction.

  15. Design of ultraviolet wavelength and standard solution concentrations in relative response factors for simultaneous determination of multi-components with single reference standard in herbal medicines.

    PubMed

    Yang, Ting-Wen; Zhao, Chao; Fan, Yong; Qi, Lian-Wen; Li, Ping

    2015-10-10

    Single standard to determine multi-components (SSDMC) is a practical pattern for quality evaluation of herbal medicines (HMs). However, it remains challenging because of potential inconsistency of relative response factors (RRF) on different instruments. In this work, the effects of two key roles, i.e., ultraviolet (UV) wavelength and standard solution concentrations, on reproducibility of RRF were investigated. The effect of UV wavelength on reproducibility of RRF was studied by plotting the relationship of the peak area ratios (internal standard vs analyte) to wavelengths. The preferable wavelength should be set at the flat parts of the curve. Optimized 300 nm produced a 0.38% RSD for emodin/emodin-8-O-β-D-glucopyranoside on five instruments, much lower than 2.80% obtained from the maximum wavelength at 290 nm. Next, the effects of standard solution concentrations of emodin on its response factor (RF) were investigated. For one single point method, low concentration less than 49 b/k resulted in significant variations in RF. For emodin, when the concentration is higher than 7.00 μg mL(-1), a low standard deviation (SD) value at 0.13 was obtained, while lower than 7.00 μg mL(-1), a high SD at 3.71 was obtained. The developed SSDMC method was then applied to determination of target components in 10 Polygonum cuspidatum samples and showed comparable accuracy to conventional calibration methods with deviation less than 1%. PMID:26093242

  16. The electro-optical characteristics of liquid crystal device in multi-component liquid crystal mixture system with non-contact photo-induced vertical alignment mode

    NASA Astrophysics Data System (ADS)

    Lin, Fa-Hsin; Ho, Czung-Yu; Lee, Jiunn-Yih

    2012-05-01

    In previous studies, we mixed photo-curable acrylic pre-polymer into negative dielectric anisotropy nematic type liquid crystal (N-type LC, NLC) to obtain a NLC/photo-curable acrylic pre-polymer mixture solution (NLC mixture system). After irradiation with UV light of fixed intensity, we successfully fabricated copolymer films with vertical alignment effect among the LC molecules. In this study, we propose a new type of multi-component LC mixture system by mixing chiral smectic type (SmA*) LC with homeotropic texture into NLC/photo-curable acrylic pre-polymer mixture system (NSLC mixture system). Our experimental results revealed that this SmA* LC exhibited the vertical alignment effect associated with LC molecules in the auxiliary LC mixture system. Moreover, we also discovered that altering the main chain type biphenol acrylic pre-polymer had drastic impact on the contrast ratio (CR) of the LC mixture system, with an increase of as much as 73%. More importantly, adding the SmA* LC can evidently increase the anchoring energy of the alignment film surface. We also further performed measurements, analyses, and discussions of electro-optical properties of devices fabricated from the new LC mixture systems.

  17. Effect of hydrothermal condition on the formation of multi-component oxides of Ni-based metallic glass under high temperature water near the critical point

    DOE PAGESBeta

    Kim, J. S.; Kim, S. Y.; Kim, D. H.; Ott, R. T.; Kim, H. G.; Lee, M. H.

    2015-07-01

    The specific feature of multi-component oxides synthesized by hydrothermal process under high temperature (633 K) and highly pressurized water (18.9 MPa) near critical point. Effects of hydrothermal processing duration times 24 hours and 72 hours, respectively, on the oxide formation of the Ni59Zr20Ti16Si2Sn3 metallic glass synthesized by powder metallurgy process were characterized by X-ray diffractometer, differential scanning calorimeter along with the particle size, morphology and crystalline phase of the oxides. The crystallization of the needle-shape NiTiO3, ZrTiO4 and ZrSnO4 ternary oxide phases observed on the surface of metallic glass at below glass transition temperature and the morphology of oxide phasesmore » changed to plate-shape around 2 μm in diameter by the increase processing time. This hydrothermal processing in subcritical water provides accelerated dense metal oxide crystals due to the reaction medium being at higher pressure than conventional oxidation processing.« less

  18. Dual-modality in vivo imaging for MRI detection of tumors and NIRF-guided surgery using multi-component nanoparticles

    NASA Astrophysics Data System (ADS)

    Key, Jaehong; Kim, Kwangmeyung; Dhawan, Deepika; Knapp, Deborah W.; Kwon, Ick Chan; Choi, Kuiwon; Leary, James F.

    2011-03-01

    Magnetic resonance imaging (MRI) is one of the best imaging modalities for noninvasive cancer detection but MRI does not have enough sensitivity to delineate tumor margins during surgery. Moreover, since most surgical tools contain metal substances, image-guided surgery is hard to perform with a MR machine using magnets. Also, MR imaging is too slow for real-time guided-surgery. On the other hand, near infrared fluorescence (NIRF) imaging has recently received great interest for in vivo imaging due to its high signal-to-noise ratios and short image-acquisition times. NIRF imaging can be used to delineate tumor margins during surgery, but current NIRF imaging cannot provide the penetration depth to detect early-stage cancer inside body. Thus, we have developed dual-modality in vivo imaging for MRI detection of tumors and NIRF-guided surgery using multi-component nanoparticles. NIRF dye (cyanine 5.5, Cy5.5), conjugated glycol chitosan nanoparticles (HGC) exhibited excellent tumor targeting ability with NIRF imaging. Superparamagnetic iron oxide (SPIO) nanoparticles as a MR contrast agent were loaded into the nanoparticles, resulting in SPIO-HGC-Cy5.5 nanoparticles. SPIO-HGC-Cy5.5 nanoparticles were characterized and evaluated in mice by both NIRF and MR imaging. Our results indicate SPIO-HGC-Cy5.5 nanoparticles have the potential for dual-modality in vivo imaging with MRI detection of tumors and NIRF-guided surgery.

  19. Food sustainability education as a route to healthier eating: evaluation of a multi-component school programme in English primary schools.

    PubMed

    Jones, M; Dailami, N; Weitkamp, E; Salmon, D; Kimberlee, R; Morley, A; Orme, J

    2012-06-01

    Promising approaches to the promotion of healthier eating among children in primary school settings include the opportunity to practise practical cooking and growing, promoting the take up of healthier school meals and nutritional education. However, less is known about the potential for strategies that integrate approaches through a focus on food sustainability issues--such as the promotion of awareness about local, seasonal, organic, fair trade and higher animal welfare foods. This paper presents an evaluation of the Food for Life Partnership, a multi-component programme that sought to address both the health and sustainability aspects of food. The study consisted of a two-stage cross-sectional survey of Years 5 and 6 students (ages 9-11) in 30 primary schools at enrolment and after 18-24 months, combined with an analysis of programme delivery. Higher self-reported fruit and vegetable consumption in the second stage survey was associated with a range of indicators of school participation in the programme. These included the reform of school meal procurement and preparation; experiential food growing, cooking and farm-based education and improved opportunities for stakeholder engagement. The study therefore develops a case for multilevel programmes that incorporate sustainability issues alongside experiential food education in primary school settings. PMID:22355199

  20. New multi-component solid forms of anti-cancer drug Erlotinib: role of auxiliary interactions in determining a preferred conformation.

    PubMed

    Sanphui, Palash; Rajput, Lalit; Gopi, Shanmukha Prasad; Desiraju, Gautam R

    2016-06-01

    Erlotinib is a BCS (biopharmaceutical classification system) class II drug used for the treatment of non-small cell lung cancer. There is an urgent need to obtain new solid forms of higher solubility to improve the bioavailability of the API (active pharmaceutical ingredient). In this context, cocrystals with urea, succinic acid, and glutaric acid and salts with maleic acid, adipic acid, and saccharin were prepared via wet granulation and solution crystallizations. Crystal structures of the free base (Z' = 2), cocrystals of erlotinib-urea (1:1), erlotinib-succinic acid monohydrate (1:1:1), erlotinib-glutaric acid monohydrate (1:1:1) and salts of erlotinib-adipic acid adipate (1:0.5:0.5) are determined and their hydrogen-bonding patterns are analyzed. Self recognition via the (amine) N-H...N (pyridine) hydrogen bond between the API molecules is replaced by several heterosynthons such as acid-pyridine, amide-pyridine and carboxylate-pyridinium in the new binary systems. Auxiliary interactions play an important role in determining the conformation of the API in the crystal. FT-IR spectroscopy is used to distinguish between the salts and cocrystals in the new multi-component systems. The new solid forms are characterized by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) to confirm their unique phase identity. PMID:27240760

  1. Ion Partitioning at the liquid/vapor interface of a multi-component alkali halidesolution: A model for aqueous sea salt aerosols

    SciTech Connect

    Ghosal, Sutapa; Brown, Matthew A.; Bluhm, Hendrik; Krisch, Maria J.; Salmeron, Miquel; Jungwirth, Pavel; Hemminger, John C.

    2008-12-22

    The chemistry of Br species associated with sea salt ice and aerosols has been implicated in the episodes of ozone depletion reported at Arctic sunrise. However, Br{sup -} is only a minor component in sea salt, which has a Br{sup -}/Cl{sup -} molar ratio of {approx}0.0015. Sea salt is a complex mixture of many different species, with NaCl as the primary component. In recent years experimental and theoretical studies have reported enhancement of the large, more polarizable halide ion at the liquid/vapor interface of corresponding aqueous alkali halide solutions. The proposed enhancement is likely to influence the availability of sea salt Br{sup -} for heterogeneous reactions such as those involved in the ozone depletion episodes. We report here ambient pressure x-ray photoelectron spectroscopy studies and molecular dynamics simulations showing direct evidence of Br{sup -} enhancement at the interface of an aqueous NaCl solution doped with bromide. The experiments were carried out on samples with Br{sup -}/Cl{sup -} ratios in the range 0.1% to 10%, the latter being also the ratio for which simulations were carried out. This is the first direct measurement of interfacial enhancement of Br{sup -} in a multi-component solution with particular relevance to sea salt chemistry.

  2. Effect of hydrothermal condition on the formation of multi-component oxides of Ni-based metallic glass under high temperature water near the critical point

    SciTech Connect

    Kim, J. S.; Lee, M. H.; Kim, S. Y.; Kim, D. H.; Ott, R. T.; Kim, H. G.

    2015-07-15

    The specific feature of multi-component oxides synthesized by hydrothermal process under high temperature (633 K) and highly pressurized water (18.9 MPa) near critical point. Effects of hydrothermal processing duration times 24 hours and 72 hours, respectively, on the oxide formation of the Ni{sub 59}Zr{sub 20}Ti{sub 16}Si{sub 2}Sn{sub 3} metallic glass synthesized by powder metallurgy process were characterized by X-ray diffractometer, differential scanning calorimeter along with the particle size, morphology and crystalline phase of the oxides. The crystallization of the needle-shape NiTiO{sub 3}, ZrTiO{sub 4} and ZrSnO{sub 4} ternary oxide phases observed on the surface of metallic glass at below glass transition temperature and the morphology of oxide phases changed to plate-shape around 2 μm in diameter by the increase processing time. This hydrothermal processing in subcritical water provides accelerated dense metal oxide crystals due to the reaction medium being at higher pressure than conventional oxidation processing.

  3. Effect of hydrothermal condition on the formation of multi-component oxides of Ni-based metallic glass under high temperature water near the critical point

    SciTech Connect

    Kim, J. S.; Kim, S. Y.; Kim, D. H.; Ott, R. T.; Kim, H. G.; Lee, M. H.

    2015-07-01

    The specific feature of multi-component oxides synthesized by hydrothermal process under high temperature (633 K) and highly pressurized water (18.9 MPa) near critical point. Effects of hydrothermal processing duration times 24 hours and 72 hours, respectively, on the oxide formation of the Ni59Zr20Ti16Si2Sn3 metallic glass synthesized by powder metallurgy process were characterized by X-ray diffractometer, differential scanning calorimeter along with the particle size, morphology and crystalline phase of the oxides. The crystallization of the needle-shape NiTiO3, ZrTiO4 and ZrSnO4 ternary oxide phases observed on the surface of metallic glass at below glass transition temperature and the morphology of oxide phases changed to plate-shape around 2 μm in diameter by the increase processing time. This hydrothermal processing in subcritical water provides accelerated dense metal oxide crystals due to the reaction medium being at higher pressure than conventional oxidation processing.

  4. Introduction: The Pan-Eurasian Experiment (PEEX) - multi-disciplinary, multi-scale and multi-component research and capacity building initiative

    NASA Astrophysics Data System (ADS)

    Kulmala, M.; Lappalainen, H. K.; Petäjä, T.; Kurten, T.; Kerminen, V.-M.; Viisanen, Y.; Hari, P.; Bondur, V.; Kasimov, N.; Kotlyakov, V.; Matvienko, G.; Baklanov, A.; Guo, H. D.; Ding, A.; Hansson, H.-C.; Zilitinkevich, S.

    2015-08-01

    The Pan-Eurasian Experiment (PEEX) is a multi-disciplinary, multi-scale and multi-component research, research infrastructure and capacity building program. PEEX has originated from a bottom-up approach by the science communities, and is aiming at resolving the major uncertainties in Earth System Science and global sustainability issues concerning the Arctic and boreal Pan-Eurasian regions, as well as China. The vision of PEEX is to solve interlinked global grand challenges influencing human well-being and societies in northern Eurasia and China. Such challenges include climate change, air quality, biodiversity loss, urbanization, chemicalization, food and fresh water availability, energy production and use of natural resources by mining, industry, energy production and transport sectors. Our approach is integrative and supra-disciplinary, recognizing the important role of the Arctic and boreal ecosystems in the Earth system. The PEEX vision includes establishing and maintaining long-term, coherent and coordinated research activities as well as continuous, comprehensive research and educational infrastructures and related capacity building across the PEEX domain. In this paper we present the PEEX structure, summarize its motivation, objectives and future outlook.

  5. Kinetic and geometrical isotope effects in hydrogen-atom transfer reaction, as calculated by the multi-component molecular orbital method

    NASA Astrophysics Data System (ADS)

    Ishimoto, Takayoshi; Tachikawa, Masanori; Tokiwa, Hiroaki; Nagashima, Umpei

    2005-07-01

    To estimate the kinetic isotope effect (KIE) for hydrogen (or deuterium) abstraction from H(D)OR (R = H, CH 3, and CN) by an OH radical, we have considered the geometrical isotope effect (GIE) induced by the difference of the protonic and deuteronic wavefunctions using the multi-component MO method. The difference by the GIE of hydrogen bond was about 0.005 Å. The ratio (kaH/kaD) of the rate constant of the reaction for R = H, HO + HOR → HOH + OR and HO + DOR → HOD + OR, is estimated as 4.4 by our calculation, which is reasonable agreement with experimental result of 6.0 ± 2.0. We have found that the difference of the nuclear wavefunction of the proton and deuteron affects the changes of geometry and electronic charge density, which plays an important role to theoretically determine the effective potential energy surfaces and the corresponding KIE between H and D compounds.

  6. Effect of Three-year Multi-Component Exercise Training on Bone Mineral Density and Content in a Postmenopausal Woman with Osteoporosis: A Case Report

    PubMed Central

    MOVASEGHI, Farzaneh; SADEGHI, Heydar

    2015-01-01

    The purpose of the present study was to examine the effect of 3-years of moderate multi-component exercise training on bone mineral density and bone mineral content in a female subject with osteoporosis. A 57-year-old postmenopausal woman, a known case of osteoporosis following an accident, participated in this study. Bone mineral density and bone mineral content was measured in the femoral neck area and the lumbar spine by dual energy X-ray absorptiometry. The measurements lasted four years, first year without any exercise training and three succeeding years with exercise intervention. After three years of exercise training, bone mineral density and bone mineral content were improved in both regions, despite the increase in age and decrease in weight. This case highlights the importance of exercise training in maintaining and increasing bone mineral density and bone mineral content of the spine and hip in post-menopausal women. Considering its positive effects, regular and lifelong exercise training must be incorporated into peoples’ life due to the chronic nature of bone loss in aging process. PMID:26284213

  7. Effect of hydrothermal condition on the formation of multi-component oxides of Ni-based metallic glass under high temperature water near the critical point

    NASA Astrophysics Data System (ADS)

    Kim, J. S.; Kim, S. Y.; Kim, D. H.; Ott, R. T.; Kim, H. G.; Lee, M. H.

    2015-07-01

    The specific feature of multi-component oxides synthesized by hydrothermal process under high temperature (633 K) and highly pressurized water (18.9 MPa) near critical point. Effects of hydrothermal processing duration times 24 hours and 72 hours, respectively, on the oxide formation of the Ni59Zr20Ti16Si2Sn3 metallic glass synthesized by powder metallurgy process were characterized by X-ray diffractometer, differential scanning calorimeter along with the particle size, morphology and crystalline phase of the oxides. The crystallization of the needle-shape NiTiO3, ZrTiO4 and ZrSnO4 ternary oxide phases observed on the surface of metallic glass at below glass transition temperature and the morphology of oxide phases changed to plate-shape around 2 μm in diameter by the increase processing time. This hydrothermal processing in subcritical water provides accelerated dense metal oxide crystals due to the reaction medium being at higher pressure than conventional oxidation processing.

  8. [Quantitative analysis of seven phenolic acids in eight Yinqiao Jiedu serial preparations by quantitative analysis of multi-components with single-marker].

    PubMed

    Wang, Jun-jun; Zhang, Li; Guo, Qing; Kou, Jun-ping; Yu, Bo-yang; Gu, Dan-hua

    2015-04-01

    The study aims to develop a unified method to determine seven phenolic acids (neochlorogenic acid, chlorogenic acid, 4-caffeoylquinic acid, caffeic acid, isochlorogenic acid B, isochlorogenic acid A and isochlorogenic acid C) contained in honeysuckle flower that is the monarch drug of all the eight Yinqiao Jiedu serial preparations using quantitative analysis of multi-components by single-marker (QAMS). Firstly, chlorogenic acid was used as a reference to get the average relative correction factors (RCFs) of the other phenolic acids in ratios to the reference; columns and instruments from different companies were used to validate the durability of the achieved RCFs in different levels of standard solutions; and honeysuckle flower extract was used as the reference substance to fix the positions of chromatographic peaks. Secondly, the contents of seven phenolic acids in eight different Yinqiao Jiedu serial preparations samples were calculated based on the RCFs durability. Finally, the quantitative results were compared between QAMS and the external standard (ES) method. The results have showed that the durability of the achieved RCFs is good (RSD during 0.80% - 2.56%), and there are no differences between the quantitative results of QAMS and ES (the relative average deviation < 0.93%). So it can be successfully used to the quantitative control of honeysuckle flower principally prescribed in Yinqiao Jiedu serial preparations. PMID:26223132

  9. Comparison of five Lonicera flowers by simultaneous determination of multi-components with single reference standard method and principal component analysis.

    PubMed

    Gao, Wen; Wang, Rui; Li, Dan; Liu, Ke; Chen, Jun; Li, Hui-Jun; Xu, Xiaojun; Li, Ping; Yang, Hua

    2016-01-01

    The flowers of Lonicera japonica Thunb. were extensively used to treat many diseases. As the demands for L. japonica increased, some related Lonicera plants were often confused or misused. Caffeoylquinic acids were always regarded as chemical markers in the quality control of L. japonica, but they could be found in all Lonicera species. Thus, a simple and reliable method for the evaluation of different Lonicera flowers is necessary to be established. In this work a method based on single standard to determine multi-components (SSDMC) combined with principal component analysis (PCA) for control and distinguish of Lonicera species flowers have been developed. Six components including three caffeoylquinic acids and three iridoid glycosides were assayed simultaneously using chlorogenic acid as the reference standard. The credibility and feasibility of the SSDMC method were carefully validated and the results demonstrated that there were no remarkable differences compared with external standard method. Finally, a total of fifty-one batches covering five Lonicera species were analyzed and PCA was successfully applied to distinguish the Lonicera species. This strategy simplifies the processes in the quality control of multiple-componential herbal medicine which effectively adapted for improving the quality control of those herbs belonging to closely related species. PMID:26432385

  10. Development of a custom-designed echo particle image velocimetry system for multi-component hemodynamic measurements: system characterization and initial experimental results

    NASA Astrophysics Data System (ADS)

    Liu, Lingli; Zheng, Hairong; Williams, Logan; Zhang, Fuxing; Wang, Rui; Hertzberg, Jean; Shandas, Robin

    2008-03-01

    We have recently developed an ultrasound-based velocimetry technique, termed echo particle image velocimetry (Echo PIV), to measure multi-component velocity vectors and local shear rates in arteries and opaque fluid flows by identifying and tracking flow tracers (ultrasound contrast microbubbles) within these flow fields. The original system was implemented on images obtained from a commercial echocardiography scanner. Although promising, this system was limited in spatial resolution and measurable velocity range. In this work, we propose standard rules for characterizing Echo PIV performance and report on a custom-designed Echo PIV system with increased spatial resolution and measurable velocity range. Then we employed this system for initial measurements on tube flows, rotating flows and in vitro carotid artery and abdominal aortic aneurysm (AAA) models to acquire the local velocity and shear rate distributions in these flow fields. The experimental results verified the accuracy of this technique and indicated the promise of the custom Echo PIV system in capturing complex flow fields non-invasively.

  11. Gases in Seawater

    NASA Astrophysics Data System (ADS)

    Nightingale, P. D.; Liss, P. S.

    2003-12-01

    The annual gross and net primary productivity of the surface oceans is similar in size to that on land (IPCC, 2001). Marine productivity drives the cycling of gases such as oxygen (O2), dimethyl sulfide (DMS), carbon monoxide (CO), carbon dioxide (CO2), and methyl iodide (CH3I) which are of fundamental importance in studies of marine productivity, biogeochemical cycles, atmospheric chemistry, climate, and human health, respectively. For example, ˜30% of the world's population (1,570 million) is thought to be at risk of iodine-deficiency disorders that impair mental development (WHO, 1996). The main source of iodine to land is the supply of volatile iodine compounds produced in the ocean and then transferred to the atmosphere via the air-surface interface. The flux of these marine iodine species to the atmosphere is also thought to be important in the oxidation capacity of the troposphere by the production of the iodine oxide radical ( Alicke et al., 1999). A further example is that the net flux of CO2 from the atmosphere to the ocean, ˜1.7±0.5 Gt C yr-1, represents ˜30% of the annual release of anthropogenic CO2 to the atmosphere (IPCC, 2001). This net flux is superimposed on a huge annual flux (90 Gt C yr-1) of CO2 that is cycled "naturally" between the ocean and the atmosphere. The long-term sink for anthropogenic CO2 is recognized as transfer to the ocean from the atmosphere. A final example is the emission of volatile sulfur, in the form of DMS, from the oceans. Not only is an oceanic flux from the oceans needed to balance the loss of sulfur (a bioessential element) from the land via weathering, it has also been proposed as having a major control on climate due to the formation of cloud condensation nuclei (Charlson et al., 1987). Indeed, the existence of DMS and CH3I has been used as evidence in support of the Gaia hypothesis (Lovelock, 1979).There are at least four main processes that affect the concentration of gases in the water column: biological

  12. “Hard probes” of strongly-interacting atomic gases

    SciTech Connect

    Nishida, Yusuke

    2012-06-18

    We investigate properties of an energetic atom propagating through strongly interacting atomic gases. The operator product expansion is used to systematically compute a quasiparticle energy and its scattering rate both in a spin-1/2 Fermi gas and in a spinless Bose gas. Reasonable agreement with recent quantum Monte Carlo simulations even at a relatively small momentum k/kF > 1.5 indicates that our large-momentum expansions are valid in a wide range of momentum. We also study a differential scattering rate when a probe atom is shot into atomic gases. Because the number density and current density of the target atomic gas contribute to the forward scattering only, its contact density (measure of short-range pair correlation) gives the leading contribution to the backward scattering. Therefore, such an experiment can be used to measure the contact density and thus provides a new local probe of strongly interacting atomic gases.

  13. Protein-Pacing and Multi-Component Exercise Training Improves Physical Performance Outcomes in Exercise-Trained Women: The PRISE 3 Study.

    PubMed

    Arciero, Paul J; Ives, Stephen J; Norton, Chelsea; Escudero, Daniela; Minicucci, Olivia; O'Brien, Gabe; Paul, Maia; Ormsbee, Michael J; Miller, Vincent; Sheridan, Caitlin; He, Feng

    2016-01-01

    The beneficial cardiometabolic and body composition effects of combined protein-pacing (P; 5-6 meals/day at 2.0 g/kg BW/day) and multi-mode exercise (resistance, interval, stretching, endurance; RISE) training (PRISE) in obese adults has previously been established. The current study examines PRISE on physical performance (endurance, strength and power) outcomes in healthy, physically active women. Thirty exercise-trained women (>4 days exercise/week) were randomized to either PRISE (n = 15) or a control (CON, 5-6 meals/day at 1.0 g/kg BW/day; n = 15) for 12 weeks. Muscular strength (1-RM bench press, 1-RM BP) endurance (sit-ups, SUs; push-ups, PUs), power (bench throws, BTs), blood pressure (BP), augmentation index, (AIx), and abdominal fat mass were assessed at Weeks 0 (pre) and 13 (post). At baseline, no differences existed between groups. Following the 12-week intervention, PRISE had greater gains (p < 0.05) in SUs, PUs (6 ± 7 vs. 10 ± 7, 40%; 8 ± 13 vs. 14 ± 12, 43% ∆reps, respectively), BTs (11 ± 35 vs. 44 ± 34, 75% ∆watts), AIx (1 ± 9 vs. -5 ± 11, 120%), and DBP (-5 ± 9 vs. -11 ± 11, 55% ∆mmHg). These findings suggest that combined protein-pacing (P; 5-6 meals/day at 2.0 g/kg BW/day) diet and multi-component exercise (RISE) training (PRISE) enhances muscular endurance, strength, power, and cardiovascular health in exercise-trained, active women. PMID:27258301

  14. Multi-component nanoporous platinum-ruthenium-copper-osmium-iridium alloy with enhanced electrocatalytic activity towards methanol oxidation and oxygen reduction

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoting; Si, Conghui; Gao, Yulai; Frenzel, Jan; Sun, Junzhe; Eggeler, Gunther; Zhang, Zhonghua

    2015-01-01

    Multi-component nanoporous platinum-ruthenium-copper-osmium-iridium (np-PtRuCuOsIr) electrocatalyst has been facilely fabricated by chemical dealloying of mechanically alloyed AlCuPtRuOsIr precursor. The np-PtRuCuOsIr catalyst exhibits a typical three-dimensional bi-continuous interpenetrating ligament/channel structure with a length scale of ∼2.5 nm. The np-PtRuCuOsIr catalyst reaches a higher level in the mass activity (857.5 mA mgPt-1) and specific activity (3.0 mA cm-2) towards methanol oxidation compared to the commercial PtC catalyst (229.5 mA mgPt-1 and 0.5 mA cm-2 respectively). Moreover, the CO stripping peak of np-PtRuCuOsIr is 0.54 V (vs. SCE), 130 mV negative shift in comparison with the commercial PtC (0.67 V vs. SCE). The half-wave potential of np-PtRuCuOsIr is 0.900 V vs. RHE, 36 mV positive compared with that of the commercial PtC (0.864 V vs. RHE). The np-PtRuCuOsIr catalyst also shows 1.8 and 3.8 times enhancement in the mass and specific activity towards oxygen reduction than the commercial PtC. Moreover, the np-PtRuCuOsIr alloy exhibits superior oxygen reduction activities even after 15 K cycles, indicating its excellent long-term stability. The present np-PtRuCuOsIr can act as a promising candidate for the electrocatalyst in direct methanol fuel cells (DMFCs).

  15. Multi-component Reynolds-averaged Navier-Stokes simulations of Richtmyer-Meshkov instability and mixing induced by reshock at different times

    NASA Astrophysics Data System (ADS)

    Morán-López, J. T.; Schilling, O.

    2014-05-01

    Turbulent mixing generated by shock-driven acceleration of a perturbed interface is simulated using a new multi-component Reynolds-averaged Navier-Stokes (RANS) model closed with a two-equation - model. The model is implemented in a hydrodynamics code using a third-order weighted essentially non-oscillatory finite-difference method for the advection terms and a second-order central difference method for the gradients in the source and diffusion terms. In the present reshocked Richtmyer-Meshkov instability and mixing study, an incident shock with Mach number is generated in air and progresses into a sulfur hexafluoride test section. The time evolution of the predicted mixing layer widths corresponding to six shock tube test section lengths are compared with experimental measurements and three-dimensional multi-mode numerical simulations. The mixing layer widths are also compared with the analytical self-similar power-law solution of the simplified model equations prior to reshock. A set of model coefficients and initial conditions specific to these six experiments is established, for which the widths before and after reshock agree very well with experimental and numerical simulation data. A second set of general coefficients that accommodates a broader range of incident shock Mach numbers, Atwood numbers, and test section lengths is also established by incorporating additional experimental data for , , and with and with and previous RANS modeling. Terms in the budgets of the turbulent kinetic energy and dissipation rate equations are examined to evaluate the relative importance of turbulence production, dissipation and diffusion mechanisms during mixing. Convergence results for the mixing layer widths, mean fields, and turbulent fields under grid refinement are presented for each of the cases.

  16. Long residence times of rapidly decomposable soil organic matter: application of a multi-phase, multi-component, and vertically resolved model (BAMS1) to soil carbon dynamics

    NASA Astrophysics Data System (ADS)

    Riley, W. J.; Maggi, F.; Kleber, M.; Torn, M. S.; Tang, J. Y.; Dwivedi, D.; Guerry, N.

    2014-07-01

    Accurate representation of soil organic matter (SOM) dynamics in Earth system models is critical for future climate prediction, yet large uncertainties exist regarding how, and to what extent, the suite of proposed relevant mechanisms should be included. To investigate how various mechanisms interact to influence SOM storage and dynamics, we developed an SOM reaction network integrated in a one-dimensional, multi-phase, and multi-component reactive transport solver. The model includes representations of bacterial and fungal activity, multiple archetypal polymeric and monomeric carbon substrate groups, aqueous chemistry, aqueous advection and diffusion, gaseous diffusion, and adsorption (and protection) and desorption from the soil mineral phase. The model predictions reasonably matched observed depth-resolved SOM and dissolved organic matter (DOM) stocks and fluxes, lignin content, and fungi to aerobic bacteria ratios. We performed a suite of sensitivity analyses under equilibrium and dynamic conditions to examine the role of dynamic sorption, microbial assimilation rates, and carbon inputs. To our knowledge, observations do not exist to fully test such a complicated model structure or to test the hypotheses used to explain observations of substantial storage of very old SOM below the rooting depth. Nevertheless, we demonstrated that a reasonable combination of sorption parameters, microbial biomass and necromass dynamics, and advective transport can match observations without resorting to an arbitrary depth-dependent decline in SOM turnover rates, as is often done. We conclude that, contrary to assertions derived from existing turnover time based model formulations, observed carbon content and Δ14C vertical profiles are consistent with a representation of SOM consisting of carbon compounds with relatively fast reaction rates, vertical aqueous transport, and dynamic protection on mineral surfaces.

  17. Effectiveness of an additional individualized multi-component complementary medicine treatment on health-related quality of life in breast cancer patients: a pragmatic randomized trial.

    PubMed

    Witt, Claudia M; Außerer, Oskar; Baier, Susanne; Heidegger, Herbert; Icke, Katja; Mayr, Oswald; Mitterer, Manfred; Roll, Stephanie; Spizzo, Gilbert; Scherer, Arthur; Thuile, Christian; Wieser, Anton; Schützler, Lena

    2015-01-01

    The aim of this study was to evaluate the effectiveness of an additional, individualized, multi-component complementary medicine treatment offered to breast cancer patients at the Merano Hospital (South Tyrol) on health-related quality of life compared to patients receiving usual care only. A randomized pragmatic trial with two parallel arms was performed. Women with confirmed diagnoses of breast cancer were randomized (stratified by usual care treatment) to receive individualized complementary medicine (CM group) or usual care alone (usual care group). Both groups were allowed to use conventional treatment for breast cancer. Primary endpoint was the breast cancer-related quality of life FACT-B score at 6 months. For statistical analysis, we used analysis of covariance (with factors treatment, stratum, and baseline FACT-B score) and imputed missing FACT-B scores at 6 months with regression-based multiple imputation. A total of 275 patients were randomized between April 2011 and March 2012 to the CM group (n = 136, 56.3 ± 10.9 years of age) or the usual care group (n = 139, 56.0 ± 11.0). After 6 months from randomization, adjusted means for health-related quality of life were higher in the CM group (FACT-B score 107.9; 95 % CI 104.1-111.7) compared to the usual care group (102.2; 98.5-105.9) with an adjusted FACT-B score difference between groups of 5.7 (2.6-8.7, p < 0.001). Thus, an additional individualized and complex complementary medicine intervention improved quality of life of breast cancer patients compared to usual care alone. Further studies evaluating specific effects of treatment components should follow to optimize the treatment of breast cancer patients. PMID:25555830

  18. Reexamining protein-protein and protein-solvent interactions from Kirkwood-Buff analysis of light scattering in multi-component solutions

    NASA Astrophysics Data System (ADS)

    Blanco, Marco A.; Sahin, Erinc; Li, Yi; Roberts, Christopher J.

    2011-06-01

    The classic analysis of Rayleigh light scattering (LS) is re-examined for multi-component protein solutions, within the context of Kirkwood-Buff (KB) theory as well as a more generalized canonical treatment. Significant differences arise when traditional treatments that approximate constant pressure and neglect concentration fluctuations in one or more (co)solvent/co-solute species are compared with more rigorous treatments at constant volume and with all species free to fluctuate. For dilute solutions, it is shown that LS can be used to rigorously and unambiguously obtain values for the osmotic second virial coefficient (B22), in contrast with recent arguments regarding protein interactions deduced from LS experiments. For more concentrated solutions, it is shown that conventional analysis over(under)-estimates the magnitude of B22 for significantly repulsive(attractive) conditions, and that protein-protein KB integrals (G22) are the more relevant quantity obtainable from LS. Published data for α-chymotrypsinogen A and a series of monoclonal antibodies at different pH and salt concentrations are re-analyzed using traditional and new treatments. The results illustrate that while traditional analysis may be sufficient if one is interested in only the sign of B22 or G22, the quantitative values can be significantly in error. A simple approach is illustrated for determining whether protein concentration (c2) is sufficiently dilute for B22 to apply, and for correcting B22 values from traditional LS regression at higher c2 values. The apparent molecular weight M2, app obtained from LS is shown to generally not be equal to the true molecular weight, with the differences arising from a combination of protein-solute and protein-cosolute interactions that may, in principle, also be determined from LS.

  19. Raman correlation spectroscopy: A feasibility study of a new optical correlation technique and development of multi-component nanoparticles using the reprecipitation method

    NASA Astrophysics Data System (ADS)

    Nishida, Maki

    The feasibility of Raman correlation spectroscopy (RCS) is investigated as a new temporal optical fluctuation spectroscopy in this dissertation. RCS analyzes the correlations of the intensity fluctuations of Raman scattering from particles in a suspension that undergo Brownian motion. Because each Raman emission line arises from a specific molecular bond, the RCS method could yield diffusion behavior of specific chemical species within a dispersion. Due to the nature of Raman scattering as a coherent process, RCS could provide similar information as acquired in dynamic light scattering (DLS) and be practical for various applications that requires the chemical specificity in dynamical information. The theoretical development is discussed, and four experimental implementations of this technique are explained. The autocorrelation of the intensity fluctuations from a beta-carotene solution is obtained using the some configurations; however, the difficulty in precise alignment and weak nature of Raman scattering prevented the achievement of high sensitivity and resolution. Possible fluctuations of the phase of Raman scattering could also be affecting the results. A possible explanation of the observed autocorrelation in terms of number fluctuations of particles is also examined to test the feasibility of RCS as a new optical characterization method. In order to investigate the complex systems for which RCS would be useful, strategies for the creation of a multicomponent nanoparticle system are also explored. Using regular solution theory along with the concept of Hansen solubility parameters, an analytical model is developed to predict whether two or more components will form single nanoparticles, and what effect various processing conditions would have. The reprecipitation method was used to demonstrate the formation of the multi-component system of the charge transfer complex perylene:TCNQ (tetracyanoquinodimethane) and the active pharmaceutical ingredient cocrystal

  20. Protein-Pacing and Multi-Component Exercise Training Improves Physical Performance Outcomes in Exercise-Trained Women: The PRISE 3 Study †

    PubMed Central

    Arciero, Paul J.; Ives, Stephen J.; Norton, Chelsea; Escudero, Daniela; Minicucci, Olivia; O’Brien, Gabe; Paul, Maia; Ormsbee, Michael J.; Miller, Vincent; Sheridan, Caitlin; He, Feng

    2016-01-01

    The beneficial cardiometabolic and body composition effects of combined protein-pacing (P; 5–6 meals/day at 2.0 g/kg BW/day) and multi-mode exercise (resistance, interval, stretching, endurance; RISE) training (PRISE) in obese adults has previously been established. The current study examines PRISE on physical performance (endurance, strength and power) outcomes in healthy, physically active women. Thirty exercise-trained women (>4 days exercise/week) were randomized to either PRISE (n = 15) or a control (CON, 5–6 meals/day at 1.0 g/kg BW/day; n = 15) for 12 weeks. Muscular strength (1-RM bench press, 1-RM BP) endurance (sit-ups, SUs; push-ups, PUs), power (bench throws, BTs), blood pressure (BP), augmentation index, (AIx), and abdominal fat mass were assessed at Weeks 0 (pre) and 13 (post). At baseline, no differences existed between groups. Following the 12-week intervention, PRISE had greater gains (p < 0.05) in SUs, PUs (6 ± 7 vs. 10 ± 7, 40%; 8 ± 13 vs. 14 ± 12, 43% ∆reps, respectively), BTs (11 ± 35 vs. 44 ± 34, 75% ∆watts), AIx (1 ± 9 vs. −5 ± 11, 120%), and DBP (−5 ± 9 vs. −11 ± 11, 55% ∆mmHg). These findings suggest that combined protein-pacing (P; 5–6 meals/day at 2.0 g/kg BW/day) diet and multi-component exercise (RISE) training (PRISE) enhances muscular endurance, strength, power, and cardiovascular health in exercise-trained, active women. PMID:27258301

  1. Using multi-component hydrochemical pattern for water balance calculations of intricate water resources in semi-arid regions - a case study in Wadi Al Arab, Jordan.

    NASA Astrophysics Data System (ADS)

    Siebert, Christian; Rödiger, Tino; Geyer, Stefan; Subah, Ali; Guttman, Yossi

    2013-04-01

    Groundwater harvesting in the semi-arid Wadi al Arab, located in the NW most corner of the Kingdom of Jordan, is supposed to be sustainable. However, since implementation of intense well fields, which take water from the Cretaceous A7/B2 aquifer, springs along the wadi course dried out and groundwater table dropped locally tremendous. To overcome the uncertainties in qualitatively and quantitatively characterising that water resource, a multi-component hydrochemical study was carried out within the SMART-project, which was also used to provide reliable boundary conditions to build up a transient numerical flow model. Wadi Al Arab represents a multi-aquifer system, with unknown interactions between the Cenozoic and Cretaceous aquifers. The exact identification and qualitatively characterization of the different groundwater bodies, the definition of their flow regimes and the recharge rate is a necessary step to calculate a reliable water balance and a rational policy of water management. Inter-aquifer flow prevents the benchmark treatment of the groundwater bodies and its detection by classical methods is an almost impossible task. In order to overcome these difficulties, the main known components of the multi-aquifer system were analysed for REY (REE+ Yttrium) abundance, major elements and for stable isotopes of water (δ18O and δD). The different waters in the area were than classified considering these parameters. This enabled identifying their respective replenishment areas and to elucidate the mixing processes controlled by structural features. This study shows that REY patterns are a powerful tool to decipher the lithology of the catchment area and the intricate patterns of flow paths of the aquifer systems. These information allow the correct definition of boundary conditions for a successful hydraulic modelling.

  2. Development of an in-situ multi-component reinforced Al-based metal matrix composite by direct metal laser sintering technique — Optimization of process parameters

    SciTech Connect

    Ghosh, Subrata Kumar; Bandyopadhyay, Kaushik; Saha, Partha

    2014-07-01

    In the present investigation, an in-situ multi-component reinforced aluminum based metal matrix composite was fabricated by the combination of self-propagating high-temperature synthesis and direct metal laser sintering process. The different mixtures of Al, TiO{sub 2} and B{sub 4}C powders were used to initiate and maintain the self-propagating high-temperature synthesis by laser during the sintering process. It was found from the X-ray diffraction analysis and scanning electron microscopy that the reinforcements like Al{sub 2}O{sub 3}, TiC, and TiB{sub 2} were formed in the composite. The scanning electron microscopy revealed the distribution of the reinforcement phases in the composite and phase identities. The variable parameters such as powder layer thickness, laser power, scanning speed, hatching distance and composition of the powder mixture were optimized for higher density, lower porosity and higher microhardness using Taguchi method. Experimental investigation shows that the density of the specimen mainly depends upon the hatching distance, composition and layer thickness. On the other hand, hatching distance, layer thickness and laser power are the significant parameters which influence the porosity. The composition, laser power and layer thickness are the key influencing parameters for microhardness. - Highlights: • The reinforcements such as Al{sub 2}O{sub 3}, TiC, and TiB{sub 2} were produced in Al-MMC through SHS. • The density is mainly influenced by the material composition and hatching distance. • Hatching distance is the major influencing parameter on porosity. • The material composition is the significant parameter to enhance the microhardness. • The SEM micrographs reveal the distribution of TiC, TiB{sub 2} and Al{sub 2}O{sub 3} in the composite.

  3. A Multi-Component Day-Camp Weight-Loss Program Is Effective in Reducing BMI in Children after One Year: A Randomized Controlled Trial

    PubMed Central

    Huang, Tao; Ried-Larsen, Mathias; Andersen, Lars Bo; Heidemann, Malene; Møller, Niels Christian

    2016-01-01

    The objective of the present study was to evaluate the effectiveness of a one-year multi-component immersive day-camp weight-loss intervention for children with overweight and obesity. The study design was a parallel-group randomized controlled trial. One hundred fifteen 11-13-year-old children with overweight and obesity were randomized into either: A six-week day-camp intervention arm focusing on increased physical activity, and healthy diet followed by a subsequent one-year family-based intervention, or a standard intervention arm consisting of one weekly exercise session for six weeks. Body mass index (BMI) was the primary outcome. BMI z-score, clustered cardiovascular risk z-score, and body composition were secondary outcomes. All outcomes were measured at baseline, six week-, and 52 week follow-up. After six weeks, children from the day-camp intervention arm had improved their BMI (-2.2 kg/m2 (95% CI -2.6 to -1.7, P<0.001)) and all secondary outcomes when compared to the children from the standard intervention arm. After 52 weeks, the day-camp intervention arm had a lower BMI (-1.2 kg/m2 (95% CI -1.8 to -0.5, P = 0.001)), and BMI z-score (-0.20 (95% CI -0.35 to -0.05, P = 0.008)), and clustered cardiovascular risk z-score (-0.23 (95% CI -0.37 to -0.08, P = 0.002)) compared to the standard intervention arm. No group differences were detected in body composition after 52 weeks. This study shows that the day-camp intervention arm is effective in reducing BMI and improving the metabolic health of children with overweight and obesity. However, the effects seem to be diminishing over time. PMID:27362497

  4. Adsorption of Gases on Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Mbaye, Mamadou Thiao

    This research focus in studying the interaction between various classical and quantum gases with novel carbon nanostructures, mainly carbon nanotubes (CNTs). Since their discovery by the Japanese physicist Sumio Iijima [1] carbon nanotubes have, experimentally and theoretically, been subjected to many scientific investigation. Studies of adsorption on CNTs are particularly directed toward their better usage in gas storage, gas separation, catalyst, drug delivery, and water purification. We explore the adsorption of different gases entrapped in a single, double, or multi-bundles of CNTs using computer simulations. The first system we investigate consists of Ar and Kr films adsorbed on zigzag or armchair nanotubes. Our simulations revealed that Kr atoms on intermediate size zigzag NTs undergo two phase transitions: A liquid-vapor (L→V), and liquid-commensurate (L→CS) with a fractional coverage of one Kr atoms adsorbed for every four carbon atoms. For Ar on zigzag and armchair NTs, the only transition observed is a L→V. In the second problem, we explore the adsorption of CO2 molecules in a nanotube bundle and calculate the isosteric heat of adsorption of the entrapped molecules within the groove. We observed that the lower the temperature, the higher the isosteric of adsorption. Last, we investigate the adsorption of hydrogen, Helium, and Neon gases on the groove site of two parallel nanotubes. At low temperature, the transverse motion on the plane perpendicular to the tubes' axis is frozen out and as a consequence, the heat capacity is reduced to 1/2. At high temperature, the atoms gain more degree of freedom and as a consequence the heat capacity is 5/2.

  5. Physics of Hyperpolarized Noble Gases

    NASA Astrophysics Data System (ADS)

    Happer, William

    1999-11-01

    The production of highly spin-polarized (hyperpolarized) gases by optical pumping with lasers involves spin-dependent interactions of atoms in gases, liquids, solids and on surfaces. Although enough is understood about these interactions to allow large quantities of hyperpolarized gas to be prepared, some of the basic physics is still mysterious. A better understanding of the physics would lead to worthwhile improvements in the performance of polarization systems. The most important physics involved in the production of hyperpolarized gases will be reviewed, with particular emphasis on areas where the physics is still not understood.

  6. Environmental implications of anesthetic gases.

    PubMed

    Yasny, Jeffrey S; White, Jennifer

    2012-01-01

    For several decades, anesthetic gases have greatly enhanced the comfort and outcome for patients during surgery. The benefits of these agents have heavily outweighed the risks. In recent years, the attention towards their overall contribution to global climate change and the environment has increased. Anesthesia providers have a responsibility to minimize unnecessary atmospheric pollution by utilizing techniques that can lessen any adverse effects of these gases on the environment. Moreover, health care facilities that use anesthetic gases are accountable for ensuring that all anesthesia equipment, including the scavenging system, is effective and routinely maintained. Implementing preventive practices and simple strategies can promote the safest and most healthy environment. PMID:23241038

  7. Noble gases in the moon

    NASA Technical Reports Server (NTRS)

    Manuel, O. K.; Srinivasan, B.; Hennecke, E. W.; Sinclair, D. E.

    1972-01-01

    The abundance and isotopic composition of helium, neon, argon, krypton, and xenon which were released by stepwise heating of lunar fines (15601.64) and (15271.65) were measured spectrometrically. The results of a composition of noble gases released from the lunar fines with noble gases in meteorites and in the earth are presented along with the isotopic composition of noble gases in lunar fines, in meteorites, and in the atmosphere. A study of two isotopically distinct components of trapped xenon in carbonaceous chondrites is also included.

  8. Rydberg Impurity Probes in Ultracold Gases

    NASA Astrophysics Data System (ADS)

    Mitchison, Mark; Johnson, Tomi; Plenio, Martin; Jaksch, Dieter

    2015-03-01

    Impurities immersed in ultracold gases can act as highly sensitive, tunable and potentially non-destructive probes of their environment. In this setting, we propose the use of an atomic impurity in a Rydberg state to measure density fluctuations via Ramsey interferometry. The rapid collisional dynamics of the light Rydberg electron interacting with the heavy gas particles, combined with the capability to quickly change the state of the impurity with optical pulses, make such a probe ideal for measuring local properties of ultracold gases. Our proposed device promises angle-resolved density measurements with sub-micron spatial resolution, and with no need to integrate over the line of sight. We outline how Rydberg impurity probes could be applied to study various interesting quantum states of current experimental relevance. We also discuss the possibility of using multiple Rydberg atoms to extract the spatial pair distribution function g (2) (r). Our work is placed in the context of other recently proposed impurity-based probes.

  9. Effectiveness of a one-year multi-component day-camp intervention for overweight children: study protocol of the Odense overweight intervention study (OOIS)

    PubMed Central

    2014-01-01

    Background Childhood overweight has noticeable psychological and social consequences for the child and leads to an increased risk of mortality and morbidity later in life. With the high prevalence of overweight in children and adolescents, it is important to identify effective approaches for the prevention and treatment of overweight in children and young individuals. The primary aim of the study is to assess the effect of an intensive day-camp intervention on body mass index (BMI) in overweight children. Methods The Odense Overweight Intervention Study is a semi-blinded randomized controlled trial. Overweight children from the Municipality of Odense, Denmark, were invited to participate in the trial. Based on power calculations 98 participants were found to be sufficient to randomize in order to find an effect of minimum 1.5 BMI points. Gender-stratified concealed block randomization with a ratio of 1:1 and random block sizes of two, four, and six ensured balance between study arms. The intervention consisted of a six-week multi-component day camp including increased physical activity, healthy diet and health education followed by 46 weeks of family-based habitual intervention. The standard care arm was offered two weekly hours of physical activity training for six weeks. The outcomes were measured at baseline and at six-week and 52-week follow-ups. Furthermore, BMI will be assessed again at 48-month follow-up. Test personnel were kept blinded. The intervention effect will be evaluated using mixed model analyses. During 2012 and 2013, 115 children were enrolled in the study. Fifty-nine children were randomized to the day-camp intervention arm and 56 to the standard intervention arm. Discussion This study will provide novel information about the long-term health effects of an intense day-camp intervention program on overweight children, due to the design and the follow-up period. Moreover, it will add to the knowledge on designing and implementing feasible camp

  10. Relevance of the Pharmacokinetic and Pharmacodynamic Profiles of Puerariae lobatae Radix to Aggregation of Multi-Component Molecules in Aqueous Decoctions.

    PubMed

    Su, Bili; Kan, Yongjun; Xie, Jianwei; Hu, Juan; Pang, Wensheng

    2016-01-01

    The complexity of traditional Chinese medicines (TCMs) is related to their multi-component system. TCM aqueous decoction is a common clinical oral formulation. Between molecules in solution, there exist intermolecular strong interactions to form chemical bonds or weak non-bonding interactions such as hydrogen bonds and Van der Waals forces, which hold molecules together to form "molecular aggregates". Taking the TCM Puerariae lobatae Radix (Gegen) as an example, we explored four Gegen decoctions of different concentration of 0.019, 0.038, 0.075, and 0.30 g/mL, named G-1, G-2, G-3, and G-4. In order of molecular aggregate size (diameter) the four kinds of solution were ranked G-1 < G-2 < G-3 < G-4 by Flow Cell 200S IPAC image analysis. A rabbit vertebrobasilar artery insufficiency (VBI) model was set up and they were given Gegen decoction (GGD) at a clinical dosage of 0.82 g/kg (achieved by adjusting the gastric perfusion volume depending on the concentration). The HPLC fingerprint of rabbit plasma showed that the chemical component absorption into blood in order of peak area values was G-1 < G-2 > G-3 > G-4. Puerarin and daidzin are the major constituents of Gegen, and the pharmacokinetics of G-1 and G-2 puerarin conformed with the two compartment open model, while for G-3 and G-4, they conformed to a one compartment open model. For all four GGDs the pharmacokinetics of daidzin complied with a one compartment open model. FQ-PCR assays of rabbits' vertebrobasilar arterial tissue were performed to determine the pharmacodynamic profiles of the four GGDs. GGD markedly lowered the level of AT₁R mRNA, while the AT₂R mRNA level was increased significantly vs. the VBI model, and G-2 was the most effective. In theory the dosage was equal to the blood drug concentration and should be consistent; however, the formation of molecular aggregates affects drug absorption and metabolism, and therefore influences drugs' effects. Our data provided references for the rational use

  11. The Influence of the Ion-Plasma Synthesis Regimes on the Features of Structural-Phase State of Multi-Component Nanocomposite Al-Cr-Si-Ti-Cu-N Coatings

    NASA Astrophysics Data System (ADS)

    Korotaev, A. D.; Ditenberg, I. A.; Berezovskaya, V. R.; Denisov, K. I.; Pinzhin, Yu. P.; Borisov, D. P.

    2015-02-01

    Within the concept of formation of multi-component, nanocomposite coatings, which assumes a simultaneous nucleation of islands of mutually insoluble or slightly-soluble phases under conditions of self-assembling microstructure during their synthesis, Al-Cr-Si-Ti-Cu-N coatings are designed and formed. Using the methods of X-ray diffraction analysis, scanning and transmission electron microscopy, a comprehensive investigation is performed of the influence of the operating modes of an ion-plasma synthesis of the resulting coatings on the features of their microstructure, microhardness, and elemental and phase composition. The procedures for optimization of the regimes of formation of multi-component, nanocomposite coatings of the above system are discussed.

  12. Final report submitted to the US Department of Energy (8/15/96 to 8/14/00). [Experimental and theoretical investigation of dual laser ablation for stoichiometric large-area multi-component film growth

    SciTech Connect

    Witanachchi, Sarath; Mukherjee, Pritish

    2000-08-01

    This research involves a systematic study of the dual-laser ablation process to understand the underlying mechanisms of the process, and to investigate the applicability of this technique to the growth of multi-component thin films. In this study, time-of-flight ion probe, emission spectroscopy, and species resolved CCD imaging methods have been used as in-situ diagnostic techniques to investigate experimentally the effect of the process parameters on the plasma ionization, ion spatial distribution, species velocity distribution profiles and expansion profiles for single component systems as well as individual elements of the multi-component material system Cu(InGa)Se{sub 2}. A theoretical model that is consistent with the experimental observations has been developed. Following tasks outlined in the proposal were successfully completed in the time period 8/15/96 to 8/14/00.

  13. Specification of photonic circuits using quantum hardware description language.

    PubMed

    Tezak, Nikolas; Niederberger, Armand; Pavlichin, Dmitri S; Sarma, Gopal; Mabuchi, Hideo

    2012-11-28

    Following the simple observation that the interconnection of a set of quantum optical input-output devices can be specified using structural mode VHSIC hardware description language, we demonstrate a computer-aided schematic capture workflow for modelling and simulating multi-component photonic circuits. We describe an algorithm for parsing circuit descriptions to derive quantum equations of motion, illustrate our approach using simple examples based on linear and cavity-nonlinear optical components, and demonstrate a computational approach to hierarchical model reduction. PMID:23091208

  14. Specification of photonic circuits using quantum hardware description language

    PubMed Central

    Tezak, Nikolas; Niederberger, Armand; Pavlichin, Dmitri S.; Sarma, Gopal; Mabuchi, Hideo

    2012-01-01

    Following the simple observation that the interconnection of a set of quantum optical input–output devices can be specified using structural mode VHSIC hardware description language, we demonstrate a computer-aided schematic capture workflow for modelling and simulating multi-component photonic circuits. We describe an algorithm for parsing circuit descriptions to derive quantum equations of motion, illustrate our approach using simple examples based on linear and cavity-nonlinear optical components, and demonstrate a computational approach to hierarchical model reduction. PMID:23091208

  15. Quantum Computation and Quantum Information

    NASA Astrophysics Data System (ADS)

    Nielsen, Michael A.; Chuang, Isaac L.

    2010-12-01

    Part I. Fundamental Concepts: 1. Introduction and overview; 2. Introduction to quantum mechanics; 3. Introduction to computer science; Part II. Quantum Computation: 4. Quantum circuits; 5. The quantum Fourier transform and its application; 6. Quantum search algorithms; 7. Quantum computers: physical realization; Part III. Quantum Information: 8. Quantum noise and quantum operations; 9. Distance measures for quantum information; 10. Quantum error-correction; 11. Entropy and information; 12. Quantum information theory; Appendices; References; Index.

  16. Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.

    PubMed

    Cabrera-Lafaurie, Wilman A; Román, Félix R; Hernández-Maldonado, Arturo J

    2015-01-23

    Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts. PMID:24680542

  17. ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS: Integrability Aspects and Soliton Solutions for a System Describing Ultrashort Pulse Propagation in an Inhomogeneous Multi-Component Medium

    NASA Astrophysics Data System (ADS)

    Guo, Rui; Tian, Bo; Lü, Xing; Zhang, Hai-Qiang; Xu, Tao

    2010-09-01

    For the propagation of the ultrashort pulses in an inhomogeneous multi-component nonlinear medium, a system of coupled equations is analytically studied in this paper. Painlevé analysis shows that this system admits the Painlevé property under some constraints. By means of the Ablowitz-Kaup-Newell-Segur procedure, the Lax pair of this system is derived, and the Darboux transformation (DT) is constructed with the help of the obtained Lax pair. With symbolic computation, the soliton solutions are obtained by virtue of the DT algorithm. Figures are plotted to illustrate the dynamical features of the soliton solutions. Characteristics of the solitons propagating in an inhomogeneous multi-component nonlinear medium are discussed: (i) Propagation of one soliton and two-peak soliton; (ii) Elastic interactions of the parabolic two solitons; (iii) Overlap phenomenon between two solitons; (iv) Collision of two head-on solitons and two head-on two-peak solitons; (v) Two different types of interactions of the three solitons; (vi) Decomposition phenomenon of one soliton into two solitons. The results might be useful in the study on the ultrashort-pulse propagation in the inhomogeneous multi-component nonlinear media.

  18. Thickness dependence on the optoelectronic properties of multilayered GaSe based photodetector

    NASA Astrophysics Data System (ADS)

    Ko, Pil Ju; Abderrahmane, Abdelkader; Takamura, Tsukasa; Kim, Nam-Hoon; Sandhu, Adarsh

    2016-08-01

    Two-dimensional (2D) layered materials exhibit unique optoelectronic properties at atomic thicknesses. In this paper, we fabricated metal–semiconductor–metal based photodetectors using layered gallium selenide (GaSe) with different thicknesses. The electrical and optoelectronic properties of the photodetectors were studied, and these devices showed good electrical characteristics down to GaSe flake thicknesses of 30 nm. A photograting effect was observed in the absence of a gate voltage, thereby implying a relatively high photoresponsivity. Higher values of the photoresponsivity occurred for thicker layers of GaSe with a maximum value 0.57 AW‑1 and external quantum efficiency of of 132.8%, and decreased with decreasing GaSe flake thickness. The detectivity was 4.05 × 1010 cm Hz1/2 W‑1 at 532 nm laser wavelength, underscoring that GaSe is a promising p-type 2D material for photodetection applications in the visible spectrum.

  19. Multi-component mapping of karst features with remote sensing, digital elevation data and GIS: a case study from Central Crete

    NASA Astrophysics Data System (ADS)

    Siart, C.; Bubenzer, O.; Eitel, B.

    2009-04-01

    GIS layer intersections. The results indicate a significant altitudinal change of typical karst forms due to changing climatic thresholds. Larger depressions mostly appear at medium altitudes, while dolines are ubiquitously distributed. Besides elevation, heterogeneous petrographic attributes as well as tectonic stress lead to a spatially different intensity of karstification. Size and shape of karst features may also vary considerably with regard to the geological setting. As demonstrated by our investigations, standard RS-techniques based on satellite imagery are of great value for morphological studies but - just as the exclusive use of DEMs for karst landform detection - they can not record area wide karstification comprehensively, if solely implemented. Since applicability problems caused by unsuitable spatial and spectral resolution may hamper these methods, a multi-component approach with supplementary data as additional detection criteria helps to improve the analysis. Hence, the combination of high resolution imagery and digital elevation models offers promising prospects to further karstmorphologic mapping.

  20. Abating environmentally harmful waste gases

    NASA Astrophysics Data System (ADS)

    Sridhar, S.; Sichen, Du; Pal, U. B.; Seetharaman, S.

    2002-05-01

    A gas-purification method, based on the condensation of nitrogen, sulfur, and carbon-containing environmentally hazardous gases produced from industrial processes, is proposed in this article. The method, which utilizes the cooling capacity of waste nitrogen in the oxygen plant to condense the hazardous gases, is capable of removing hazardous impurities up to 99.98%. Theoretical calculations underlying the condensation process are presented employing gases produced in a blast furnace and coke oven in an integrated steel plant. The cooling power required for the condensation process is calculated using the waste nitrogen generated from an oxygen plant that generates captive oxygen for the steel plant. Design modifications that need to be made to the oxygen plant in order to utilize the cooling power of the waste nitrogen gas are also presented. As a case study, the advantages of the method are illustrated with purification of coke-oven gas. The economic impact and the investment aspects are also discussed.

  1. Isothermal compressors for process gases

    SciTech Connect

    Wiederuh, E.; Meinhart, D. )

    1992-09-01

    This paper reports on isothermal compressors which are more efficient for all gases. The study of several representative gases considered stage efficiencies, pressure ratios and pressure losses of the intercoolers. Generally there are two ways to reduce power consumption of a gas compression process: minimize losses of the compressor or improve the thermodynamics of the process. But there are some new ways to reduce losses of turbocompressors. Losses of the impeller labyrinth seals and the balance piston labyrinth seal can be reduced by optimizing the labyrinth geometry and minimizing labyrinth clearances. Therefore, conventional labyrinth seals are still being studied and will be improved.

  2. Conduction of Electricity through Gases

    NASA Astrophysics Data System (ADS)

    Thomson, J. J.; Thomson, G. P.

    2013-06-01

    1. Electrical conductivity of gases in a normal state; 2. Properties of a gas when in a conducting state; 3. Mobility of ions; 4. Mathematical theory of the conduction of electricity through a gas containing ions; 5. Effect produced by a magnetic field on the motion of the ions; 6. Determination of the ratio of the charge to the mass of an ion; 7. Determination of the charge carried by the negative ion; 8. On some physical properties of gaseous ions; 9. Ionisation by incandescent solids; 10. Ionisation in gases from flames; 11. Ionisation by light. Photo-electric effects; Name index; Subject index.

  3. Interaction quenches of Fermi gases

    SciTech Connect

    Uhrig, Goetz S.

    2009-12-15

    It is shown that the jump in the momentum distribution of Fermi gases evolves smoothly for small and intermediate times once an interaction between the fermions is suddenly switched on. The jump does not vanish abruptly. The loci in momentum space where the jumps occur are those of the noninteracting Fermi sea. No relaxation of the Fermi surface geometry takes place.

  4. Topology-driven quantum phase transitions in time-reversal-invariant anyonic quantum liquids

    NASA Astrophysics Data System (ADS)

    Gils, Charlotte; Trebst, Simon; Kitaev, Alexei; Ludwig, Andreas W. W.; Troyer, Matthias; Wang, Zhenghan

    2009-11-01

    Indistinguishable particles in two dimensions can be characterized by anyonic quantum statistics, which is more general than that of bosons or fermions. Anyons emerge as quasiparticles in fractional quantum Hall states and in certain frustrated quantum magnets. Quantum liquids of anyons show degenerate ground states, where the degeneracy depends on the topology of the underlying surface. Here, we present a new type of continuous quantum phase transition in such anyonic quantum liquids, which is driven by quantum fluctuations of the topology. The critical state connecting two anyonic liquids on surfaces with different topologies is reminiscent of the notion of a `quantum foam' with fluctuations on all length scales. This exotic quantum phase transition arises in a microscopic model of interacting anyons for which we present an exact solution in a linear geometry. We introduce an intuitive physical picture of this model that unifies string nets and loop gases, and provide a simple description of topological quantum phases and their phase transitions.

  5. Dynamics of nematic order in ultracold dipolar gases

    NASA Astrophysics Data System (ADS)

    Ebling, Ulrich; Ueda, Masahito

    2016-05-01

    We study dynamcial properties of ultracold atoms with strong dipole-dipole interactions, such as rare-earth atoms like Erbium or Dysprosium. Dipole-dipole interactions are anisotropic and can lead to the appearance of two types of nematic order in such quantum gases. Orbital nematic order is related to spatial anisotropies such as the deformation of a Fermi surface of an ultracold dipolar Fermi gas. Spin nematic order is present only in systems with spin larger than 1/2 as a higher moment of the spin operators. We study the case of a not fully polarized dipolar gas, such that the intrinsic coupling of spin and orbital degrees of freedom can lead to an interplay between orbital and spin nematic order. We investigate how this interplay can lead to a transfer between orbital and spin nematicity, similar to the transfer of spin into orbital angular momentum predicted for dipolar gases.

  6. Calculations of accommodation coefficients for diatomic molecular gases.

    PubMed

    Ambaye, Hailemariam; Manson, J R

    2006-03-01

    A theoretical study of energy and momentum accommodation coefficients and reduced force coefficients for molecular gases exchanging energy with surfaces has been carried out. The theoretical model uses classical mechanics for describing translational and rotational motions while internal molecular vibrational modes are treated quantum mechanically. Calculations for diatomic molecular gases are compared with recent measurements using hypersonic beams of N2 incident on SiO2 layers deposited on Kapton substrates. The theory gives good qualitative predictions of the behavior of the various accommodation coefficients as functions of the available experimentally controllable parameters such as incident translational energy, incident beam angle, molecular and surface masses, and surface temperature. Quantitative comparisons with measurements for energy and normal momentum accommodation indicate that these experiments can be used to obtain basic physical information about the molecule-surface interaction such as the physisorption potential well depth and the extent of surface roughness. PMID:16605510

  7. Fermion gases in magnetic fields: a semiclassical treatment

    NASA Astrophysics Data System (ADS)

    Molinari, V. G.; Sumini, M.; Rocchi, F.

    The study of quantum degenerate gases has received much interest in these last years essentially thanks to the extremely important experimental results of the achievement of Bose-Einstein condensation of atoms and, very recently, of almost complete degeneracy of atomic fermion gases. Here we want to present the results of a semi-analytical method for the study of an interacting degenerate fermion gas based on semiclassical kinetic theory; special care has been devoted to the study of a rotating electron gas, in a cylindrically symmetrical configuration, radially confined by a uniform magnetic field. The model will lead to a particular Thomas-Fermi equation which is generalized to take into account finite temperature and average velocity of the gas, and which is further developed to consider the effects of external fields.

  8. Effects of segregation and impact of specific feeding behaviour and additional fruit on voluntary nutrient and energy intake in yellow-shouldered amazons (Amazona barbadensis) when fed a multi-component seed diet ad libitum.

    PubMed

    Kalmar, I D; Veys, A C; Geeroms, B; Reinschmidt, M; Waugh, D; Werquin, G; Janssens, G P J

    2010-12-01

    Parrots are commonly fed multi-component seed diets; however, both segregation and feeding behaviour might alter ingredient and nutrient composition of the offered diet. First, the nutritional impact of segregation was assessed as it occurs when multi-component diets are temporarily stored in food containers that are replenished before completely emptied and birds being fed from the upper layer. The most detrimental effect hereof was a vast decrease in mineral supplements, leading to a decrease in Ca:P ratio in the offered food in relation to the formulated diet. Next, caloric distribution shifted towards more EE energy at the expense of NFE energy, as proportion of oilseeds increased and NFE-rich seeds decreased. Next, a feeding trial was performed on six yellow-shouldered amazons (Amazona Barbadensis) in which nutritional impact of parrot-specific feeding behaviour was assessed as well as the influence of additional provision of fruit next to the seed mixture. Profound selective feeding behaviour and dehusking of seeds resulted in a vast increase in energetic density by up to 64% in the ingested fraction in relation to the offered mixture in toto. Furthermore, the already suboptimal Ca:P ratio further deteriorated and caloric distribution shifted by over twofold towards EE energy accompanied with a vast decline in NFE energy, CP energy remaining similar. Finally, provision of fruit next to the seed diet significantly lowered voluntary energy intake from 936 ± 71 to 809 ± 109 kJ ME/kg(0.75)/day, without compromising adequate protein intake. In conclusion, notwithstanding efforts of nutritionists to formulate diets to approximate estimated, species-specific requirements, nutritional composition of the actually consumed fraction of multi-component seed diets can be vastly deteriorated by both animal and management factors. Furthermore, offering of fruit next to a seed-based diet effectively reduces voluntary energy intake and can hence be applied to abate obesity

  9. Multi-component synthesis of 2-amino-6-(alkyllthio)pyridine-3,5-dicarbonitriles using Zn(II) and Cd(II) metal-organic frameworks (MOFs) under solvent-free conditions

    PubMed Central

    Thimmaiah, Muralidhara; Li, Peng; Regati, Sridhar; Chen, Banglin; Zhao, John Cong-Gui

    2012-01-01

    Multi-component synthesis 2-amino-3,5-dicarbonitrile-6-thio-pyridines has been developed by using the reaction of aldehydes, malononitrile, and thiophenols in the presence of a Zn (II) or a Cd(II) metal-organic framework (MOF) as the heterogeneous catalyst. This protocol tolerates different functional groups on the substrates and does not require the use of any organic solvent. Moreover, the Zn(II) and Cd (II) MOF catalysts can be recovered and reused for a number of runs without loss of activity. PMID:23002309

  10. Spin waves in ultracold gases with exchange and spin-orbit interactions

    SciTech Connect

    Andreeva, T. L.; Rubin, P. L.

    2012-08-15

    The dynamics of spin waves in ultracold gases is investigated with allowance for exchange and spin-orbit interaction. The exact basis of atomic states is used taking into account all rotational quantum numbers of the atom. The dispersion relation for spin waves is obtained for fermions and bosons in the hydro-dynamic approximation.

  11. Mass-imbalanced Fermi gases with spin-orbit coupling

    SciTech Connect

    Iskin, M.; Subasi, A. L.

    2011-10-15

    We use the mean-field theory to analyze the ground-state phase diagrams of spin-orbit-coupled mass-imbalanced Fermi gases throughout the BCS-BEC evolution, including both the population-balanced and -imbalanced systems. Our calculations show that the competition between the mass and population imbalance and the Rashba-type spin-orbit coupling gives rise to very rich phase diagrams, involving normal, superfluid, and phase-separated regions. In addition, we find quantum phase transitions between the topologically trivial gapped superfluid and the nontrivial gapless superfluid phases, opening the way for the experimental observation of exotic phenomena with cold atom systems.

  12. Analysis of localization phenomena in weakly interacting disordered lattice gases

    NASA Astrophysics Data System (ADS)

    Schulte, T.; Drenkelforth, S.; Kruse, J.; Sacha, K.; Zakrzewski, J.; Lewenstein, M.; Arlt, J. J.; Ertmer, W.

    2007-02-01

    Although disorder plays a crucial role in many systems, it can usually not be chosen or controlled. We show that the unique methods available for ultracold atomic gases may be used for the controllable production and observation of disordered quantum systems. A detailed analysis of localization effects for two possible realizations of a disordered potential is presented. In a theoretical analysis clear localization effects are observed when a superlattice is used to provide a quasiperiodic disorder. The effects of localization are analyzed by investigating the superfluid fraction and the localization length within the system.

  13. Cold Atomic Gases in Optical Lattices with Disorder

    NASA Astrophysics Data System (ADS)

    Schulte, T.; Drenkelforth, S.; Kruse, J.; Ertmer, W.; Arlt, J. J.; Kantian, A.; Santos, L. Sanchez-Palencia L.; Sanpera, A.; Sacha, K.; Zoller, P.; Lewenstein, M.; Zakrzewski, J.

    2007-01-01

    Cold atomic gases placed in optical lattices enable studies of simple condensed matter theory models with parameters that may be tuned relatively easily. When the optical potential is randomized (e.g. using laser speckle to create a random intensity distribution) one may be able to observe Anderson localization of matter waves for non-interacting bosons, the so-called Bose glass in the presence of interactions, as well as the Fermi glass or quantum spin glass for mixtures of fermions and bosons.

  14. Isotopic Analysis and Evolved Gases

    NASA Technical Reports Server (NTRS)

    Swindle, Timothy D.; Boynton, William V.; Chutjian, Ara; Hoffman, John H.; Jordan, Jim L.; Kargel, Jeffrey S.; McEntire, Richard W.; Nyquist, Larry

    1996-01-01

    Precise measurements of the chemical, elemental, and isotopic composition of planetary surface material and gases, and observed variations in these compositions, can contribute significantly to our knowledge of the source(s), ages, and evolution of solar system materials. The analyses discussed in this paper are mostly made by mass spectrometers or some other type of mass analyzer, and address three broad areas of interest: (1) atmospheric composition - isotopic, elemental, and molecular, (2) gases evolved from solids, and (3) solids. Current isotopic data on nine elements, mostly from in situ analysis, but also from meteorites and telescopic observations are summarized. Potential instruments for isotopic analysis of lunar, Martian, Venusian, Mercury, and Pluto surfaces, along with asteroid, cometary and icy satellites, surfaces are discussed.

  15. Strongly Interacting Homogeneous Fermi Gases

    NASA Astrophysics Data System (ADS)

    Mukherjee, Biswaroop; Patel, Parth; Yan, Zhenjie; Struck, Julian; Zwierlein, Martin

    2016-05-01

    We present a homogeneous box potential for strongly interacting Fermi gases. The local density approximation (LDA) allows measurements on traditional inhomogeneous traps to observe a continuous distribution of Fermi gases in a single shot, but also suffer from a broadened response due to line-of-sight averaging over varying densities. We trap ultracold Fermionic (6 Li) in an optical homogeneous potential and characterize its flatness through in-situ tomography. A hybrid approach combining a cylindrical optical potential with a harmonic magnetic trap allows us to exploit the LDA and measure local RF spectra without requiring significant image reconstruction. We extract various quantities from the RF spectra such as the Tan's contact, and discuss further measurements of homogeneous Fermi systems under spin imbalance and finite temperature.

  16. Thermodynamics, Hydrodynamics and Damping in Ultracold Gases

    NASA Astrophysics Data System (ADS)

    Chafin, Clifford

    Ultracold gases have provided experimental systems that span microscopic to macroscopic regimes of behavior and over a range of internal energy scales and interaction strengths that drive behavior from ballistic to hydrodynamic and degenerate to correlated. Here we will examine these systems from several points of view. First, we present a discussion from the standpoint of the evolution of a single many body wavefunction. In support of this picture we examine the longstanding vagueness surrounding measurement and thermalization and show the situation here is significantly better from this point of view than generally presented. The implications for how well defined a temperature can be achieved by various trap manipulation is discussed along with proposed experiments to distinguish these cases. Since hydrodynamic methods have worked well in some cases we then discuss the unitary limit for fermions with contact limited interactions. The scale invariance of the system implies limits on hydrodynamic behavior from which we extract bounds on viscous damping from free expansion and trap oscillation experiments. Linear response theory is used to probe the effect of quantum fluctuations on the viscosity and some nonuniversal contributions are derived. These show that the classical gradient expansion of hydrodynamics breaks down at lower than Burnett order, where problems with the classical expansions typically occur.

  17. Annihilation in Gases and Galaxies

    NASA Technical Reports Server (NTRS)

    Drachman, Richard J. (Editor)

    1990-01-01

    This publication contains most of the papers, both invited and contributed, that were presented at the Workshop of Annihilation in Gases and Galaxies. This was the fifth in a biennial series associated with the International Conference on the Physics of Electronic and Atomic Collisions. Subjects covered included the scattering and annihilation of positrons and positronium atoms in various media, including those of astrophysical interest. In addition, the topics of antimatter and dark matter were covered.

  18. Atmospheric Chemistry and Greenhouse Gases

    SciTech Connect

    Ehhalt, D.; Prather, M.; Dentener, F.; Derwent, R.; Dlugokencky, Edward J.; Holland, E.; Isaksen, I.; Katima, J.; Kirchhoff, V.; Matson, P.; Midgley, P.; Wang, M.; Berntsen, T.; Bey, I.; Brasseur, G.; Buja, L.; Collins, W. J.; Daniel, J. S.; DeMore, W. B.; Derek, N.; Dickerson, R.; Etheridge, D.; Feichter, J.; Fraser, P.; Friedl, R.; Fuglestvedt, J.; Gauss, M.; Grenfell, L.; Grubler, Arnulf; Harris, N.; Hauglustaine, D.; Horowitz, L.; Jackman, C.; Jacob, D.; Jaegle, L.; Jain, Atul K.; Kanakidou, M.; Karlsdottir, S.; Ko, M.; Kurylo, M.; Lawrence, M.; Logan, J. A.; Manning, M.; Mauzerall, D.; McConnell, J.; Mickley, L. J.; Montzka, S.; Muller, J. F.; Olivier, J.; Pickering, K.; Pitari, G.; Roelofs, G.-J.; Rogers, H.; Rognerud, B.; Smith, Steven J.; Solomon, S.; Staehelin, J.; Steele, P.; Stevenson, D. S.; Sundet, J.; Thompson, A.; van Weele, M.; von Kuhlmann, R.; Wang, Y.; Weisenstein, D. K.; Wigley, T. M.; Wild, O.; Wuebbles, D.J.; Yantosca, R.; Joos, Fortunat; McFarland, M.

    2001-10-01

    Chapter 4 of the IPCC Third Assessment Report Climate Change 2001: The Scientific Basis. Sections include: Executive Summary 2414.1 Introduction 2434.2 Trace Gases: Current Observations, Trends and Budgets 2484.3 Projections of Future Emissions 2664.4 Projections of Atmospheric Composition for the 21st Century 2674.5 Open Questions 2774.6 Overall Impact of Global Atmospheric Chemistry Change 279

  19. 40 CFR 92.112 - Analytical gases.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Analytical gases. 92.112 Section 92...) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.112 Analytical gases. (a) Gases for the CO and CO2 analyzers shall be single blends of CO and CO2, respectively, using...

  20. A multi-component statistic analysis for the influence of sediment/soil composition on the sorption of a nonionic surfactant (Triton X-100) onto natural sediments/soils.

    PubMed

    Zhu, Lizhong; Yang, Kun; Lou, Baofeng; Yuan, Bihao

    2003-11-01

    The contents of soil/sediment organic carbon and clay minerals (i.e. montmorillonite, kaolinite, illite, gibbsite and 1.4 nm minerals) for 21 natural soil/sediment samples and the sorption of Triton X-100 on these samples were determined. A multi-component statistic analysis was employed to investigate the importance of soil/sediment organic matters and clay minerals on their sorption of Triton X-100. The sorption power of soil/sediment composition for Triton X-100 conforms to an order of montmorillonite>organic carbon>illite>1.4 nm minerals (vermiculite+chlorite+1.4 nm intergrade mineral)>kaolinite. The sorption of Triton X-100 on a montmorillonite, a kaolinite and a humic acid were also investigated and consistent with the result of multi-component statistic analysis. It is clear that the sorption of Triton X-100 on soils or sediments is the combined contribution of soil/sediment organic matters and clay minerals, which depended on both the contents of soil/sediment organic matters and the types and contents of clay minerals. The important influence of illite on the sorption of nonionic surfactants onto soils/sediments is suggested and demonstrated in this paper. Surfactants for aquifer remediation application may be more efficient for the contaminated soils/sediments that contain little clay minerals with 2:1 structure because of the less sorption of nonionic surfactants on these soils/sediments. PMID:14568066

  1. Thermodynamics and statistical mechanics. [thermodynamic properties of gases

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The basic thermodynamic properties of gases are reviewed and the relations between them are derived from the first and second laws. The elements of statistical mechanics are then formulated and the partition function is derived. The classical form of the partition function is used to obtain the Maxwell-Boltzmann distribution of kinetic energies in the gas phase and the equipartition of energy theorem is given in its most general form. The thermodynamic properties are all derived as functions of the partition function. Quantum statistics are reviewed briefly and the differences between the Boltzmann distribution function for classical particles and the Fermi-Dirac and Bose-Einstein distributions for quantum particles are discussed.

  2. Cavity-induced chiral states of fermionic quantum gases

    NASA Astrophysics Data System (ADS)

    Sheikhan, Ameneh; Brennecke, Ferdinand; Kollath, Corinna

    2016-04-01

    We investigate ultracold fermions placed into an optical cavity and subjected to optical lattices which confine the atoms to ladder structures. A transverse running-wave laser beam induces together with the dynamical cavity field a two-photon Raman-assisted tunneling process with spatially dependent phase imprint along the rungs of the ladders. We identify the steady states which can occur by the feedback mechanism between the cavity field and the atoms. We find the spontaneous emergence of a finite cavity field amplitude which leads to an artificial magnetic field felt by the fermionic atoms. These form a chiral insulating or chiral liquid state carrying a chiral current. We explore the rich state diagram as a function of the power of the transverse laser beam, the atomic filling, and the phase imprint during the cavity-induced tunneling. Both a sudden onset or a slow exponential activation with the transverse laser power of the self-organized chiral states can occur.

  3. Conditions for one-dimensional supersonic flow of quantum gases

    NASA Astrophysics Data System (ADS)

    Giovanazzi, S.; Farrell, C.; Kiss, T.; Leonhardt, U.

    2004-12-01

    One can use transsonic Bose-Einstein condensates of alkali atoms to establish the laboratory analog of the event horizon and to measure the acoustic version of Hawking radiation. We determine the conditions for supersonic flow and the Hawking temperature for realistic condensates on waveguides where an external potential plays the role of a supersonic nozzle. The transition to supersonic speed occurs at the potential maximum and the Hawking temperature is entirely determined by the curvature of the potential.

  4. Topological quantum matter with ultracold gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Goldman, N.; Budich, J. C.; Zoller, P.

    2016-07-01

    Since the discovery of topological insulators, many topological phases have been predicted and realized in a range of different systems, providing both fascinating physics and exciting opportunities for devices. And although new materials are being developed and explored all the time, the prospects for probing exotic topological phases would be greatly enhanced if they could be realized in systems that were easily tuned. The flexibility offered by ultracold atoms could provide such a platform. Here, we review the tools available for creating topological states using ultracold atoms in optical lattices, give an overview of the theoretical and experimental advances and provide an outlook towards realizing strongly correlated topological phases.

  5. Strongly interacting ultracold quantum gases of fermionic ytterbium-173

    NASA Astrophysics Data System (ADS)

    Höfer, Moritz; Riegger, Luis; Hofrichter, Chrisitian; Rio Fernandes, Diogo; Fölling, Simon; Bloch, Immanuel

    2016-05-01

    In contrast to the more common alkali atoms, alkaline-earth-like ytterbium features a strong decoupling between the nuclear and the electronic spin degree of freedom and possesses a metastable excited state. The decoupling gives rise to an extended SU(N)-symmetry with N <= 6 for ytterbium-173. This enables us to study the SU(N)-symmetric Fermi-Hubbard model in a three-dimensional optical lattice. We prepare a low-temperature SU(N)-symmetric Mott insulator and characterize the Mott crossover. High local resolution allows us to extract the equation of state for a large range of interactions. In a second experiment, we investigate the scattering properties between the 1 S0 ground state and 3 P0 metastable state, where the interactions cannot be tuned with standard magnetic Feshbach resonances as in alkalis. We report on the discovery of a new orbital interaction-induced Feshbach resonance in ytterbium-173, permitting tunable interactions between these two states.

  6. Fermionic quantum gases with tunable interactions in optical lattices

    NASA Astrophysics Data System (ADS)

    Schneider, Ulrich; Hackermüller, Lucia; Best, Thorsten; Will, Sebastian; Braun, Simon; Moreno Cardoner, Maria; Paredes, Belen; Bloch, Immanuel

    2009-03-01

    Fermionic atoms in optical lattices can serve as a model system for condensed matter physics, as they present an implementation of the Hubbard hamiltonian with high experimental control of the relevant parameters. In our system we sympathetically cool ^87Rb and ^40K in an optically plugged quadrupole trap and an optical dipole trap. After evaporation, a balanced spin mixture of 40K atoms is loaded into a blue detuned optical lattice where the interactions can be changed via a Feshbach resonance. We present experimental and theoretical studies of the behaviour of fermionic atoms for both attractive and repulsive interactions. For repulsive interactions we show a transition from compressible, metallic states to Mott-insulating and finally band insulating states. On the attractive side we investigate an anomalous expansion when the interaction is strongly attractive and study the dynamics of atoms and repulsively and attractively bound pairs.

  7. Thermodynamics of Trapping Gases for Underwater Superhydrophobicity.

    PubMed

    Patankar, Neelesh A

    2016-07-12

    Rough surfaces submerged in a liquid can remain almost dry if the liquid does not fully wet the roughness, and gases are sustained in roughness grooves. Such partially dry surfaces can help reduce drag, enhance boiling, and reduce biofouling. Gases sustained in roughness grooves would be composed of air and the vapor phase of the liquid itself. In this work, the thermodynamics of sustaining gases (e.g., air) is considered. Governing equations are presented along with a solution methodology to determine a critical condition to sustain gases. The critical roughness scale to sustain gases is estimated for different degrees of saturation of gases dissolved in the liquid. It is shown that roughness spacings of less than a micron are essential to sustain gases on surfaces submerged in water at atmospheric pressure. This is consistent with prior empirical data. PMID:27276525

  8. Magnetic crystals and helical liquids in alkaline-earth fermionic gases.

    PubMed

    Barbarino, Simone; Taddia, Luca; Rossini, Davide; Mazza, Leonardo; Fazio, Rosario

    2015-01-01

    The joint action of a magnetic field and of interactions is crucial for the appearance of exotic quantum phenomena, such as the quantum Hall effect. Owing to their rich nuclear structure, equivalent to an additional synthetic dimension, one-dimensional alkaline-earth(-like) fermionic gases with synthetic gauge potential and atomic contact repulsion may display similar related properties. Here we show the existence and the features of a hierarchy of fractional insulating and conducting states by means of analytical and numerical methods. We demonstrate that the gapped states are characterized by density and magnetic order emerging solely for gases with effective nuclear spin larger than 1/2, whereas the gapless phases can support helical modes. We finally argue that these states are related to an unconventional fractional quantum Hall effect in the thin-torus limit and that their properties can be studied in state-of-the-art laboratories. PMID:26350624

  9. Magnetic crystals and helical liquids in alkaline-earth fermionic gases

    PubMed Central

    Barbarino, Simone; Taddia, Luca; Rossini, Davide; Mazza, Leonardo; Fazio, Rosario

    2015-01-01

    The joint action of a magnetic field and of interactions is crucial for the appearance of exotic quantum phenomena, such as the quantum Hall effect. Owing to their rich nuclear structure, equivalent to an additional synthetic dimension, one-dimensional alkaline-earth(-like) fermionic gases with synthetic gauge potential and atomic contact repulsion may display similar related properties. Here we show the existence and the features of a hierarchy of fractional insulating and conducting states by means of analytical and numerical methods. We demonstrate that the gapped states are characterized by density and magnetic order emerging solely for gases with effective nuclear spin larger than 1/2, whereas the gapless phases can support helical modes. We finally argue that these states are related to an unconventional fractional quantum Hall effect in the thin-torus limit and that their properties can be studied in state-of-the-art laboratories. PMID:26350624

  10. Eu3+, Tb3+/β-diketonate functionalized mesoporous SBA-15/GaN composites: multi-component chemical bonding assembly, characterization, and luminescence.

    PubMed

    Zhao, Yan; Yan, Bing

    2013-04-01

    GaN-functionalized rare earth (Eu3+ and Tb3+) organic/inorganic mesoporous nanocomposites have been successfully synthesized (designated as RE(L-SBA-15)3(L-GaN); RE=Eu, Tb; L=TAA-Si, BTA-Si). The organosilane precursor materials (L-SBA-15) are synthesized by co-condensation of tetraethylorthosilicate (TEOS) and the functionalized β-diketones (TAA-Si and BTA-Si) in the presence of Pluronic P123 surfactant as a template. The modified β-diketones ligands are also used to covalently bond with surface-modified GaN and formed another precursor L-GaN. Both of the precursors can coordinate with rare earth ions to synthesize the final mesoporous materials via a sol-gel process. FTIR, TEM, XRD, and nitrogen (N2) adsorption/desorption measurements are employed to characterize the mesostructure of RE(L-SBA-15)3(L-GaN). The luminescence properties and thermogravimetric analysis of all the prepared materials are characterized in detail, and the results reveal that a series of uniformed mesopore structure hybrid materials has been achieved. The mesoporous material Eu(BTA-Si-SBA-15)3(BTA-Si-GaN) has better luminescence intensity, higher quantum efficiency, and longer lifetime than Eu(TAA-Si-SBA-15)3(TAA-Si-GaN). While the nanocomposite Tb(TAA-Si-SBA-15)3(TAA-Si-GaN) revealed the strongest characteristic emission of Tb ions than Tb(BTASiSBA-15)(BTASiGaN), the excellent luminescent properties and thermal stability enable the hybrid mesoporous material to have potential applications in optical field. PMID:23374434

  11. Climate Change and Greenhouse Gases

    NASA Technical Reports Server (NTRS)

    Ledley, Tamara S.; Sundquist, Eric; Schwartz, Stephen; Hall, Dorothy K.; Fellows, Jack; Killeen, Timothy

    1999-01-01

    The American Geophysical Union (AGU), as a scientific organization devoted to research on the Earth and space sciences, provides current scientific information to the public on issues pertinent to geophysics. The Council of the AGU approved a position statement on Climate Change and Greenhouse Gases in December 1998. The statement, together with a short summary of the procedures that were followed in its preparation, review, and adoption were published in the February 2, 1999 issue of Eos ([AGU, 1999]. The present article reviews scientific understanding of this issue as presented in peer-reviewed publications that serves as the underlying basis of the position statement.

  12. Spark ignition of flowing gases

    NASA Technical Reports Server (NTRS)

    Swett, Clyde C , Jr

    1956-01-01

    Research conducted at the NACA Lewis Laboratory on ignition of flowing gases by means of long-duration discharges is summarized and analyzed. Data showing the effect of a flowing combustible mixture on the physical and electrical characteristics of spark discharges and data showing the effects of variables on the spark energy required for ignition that has been developed to predict the effect of many of the gas-stream and spark variables is described and applied to a limited amount of experimental data.

  13. Structure of Inert Gases Adsorbed in MCM-41

    NASA Astrophysics Data System (ADS)

    Evans, Dylan; Sokol, Paul

    One-dimensional quantum liquids of 3He or 4He have generated recent interest for investigation in the Luttinger liquid model. Unfortunately, current studies lack a clear demonstration of definitively one-dimensional behavior. We propose using the templated, porous material, MCM-41, as a host for an atomic Luttinger liquid. In general, the pores of MCM-41 are too wide to provide a strictly one-dimensional environment, so we investigate preplating these pores with inert gases to effectively reduce their diameter. We present the results of studies of the structure of inert gases in MCM-41. Nitrogen sorption isotherms were used to characterize the sample. Then, using inert gases as adsorbates, we determined the minimum effective pore diameter that can be achieved in our sample before capillary condensation takes over. X-ray powder diffraction (XRD) was performed on the ideally preplated sample to investigate the structure of the adsorbates in the nanopores. The XRD measurements are compared to simulations of core-shell cylinder model scattering, and the validity of the model is assessed. The prospects for creating a definitively one-dimensional channel for the application of studying the structure and dynamics of helium confined in one dimension are discussed. This work was supported by the National Science Foundation under Grant DGE-1069091.

  14. Ultracold Fermi gases with emergent SU(N) symmetry.

    PubMed

    Cazalilla, Miguel A; Rey, Ana Maria

    2014-12-01

    We review recent experimental and theoretical progress on ultracold alkaline-earth Fermi gases with emergent SU(N) symmetry. Emphasis is placed on describing the ground-breaking experimental achievements of recent years. The latter include (1) the cooling to below quantum degeneracy of various isotopes of ytterbium and strontium, (2) the demonstration of optical Feshbach resonances and the optical Stern-Gerlach effect, (3) the realization of a Mott insulator of (173)Yb atoms, (4) the creation of various kinds of Fermi-Bose mixtures and (5) the observation of many-body physics in optical lattice clocks. On the theory side, we survey the zoo of phases that have been predicted for both gases in a trap and loaded into an optical lattice, focusing on two and three dimensional systems. We also discuss some of the challenges that lie ahead for the realization of such phases such as reaching the temperature scale required to observe magnetic and more exotic quantum orders. The challenge of dealing with collisional relaxation of excited electronic levels is also discussed. PMID:25429615

  15. Ultracold Fermi gases with emergent SU(N) symmetry

    NASA Astrophysics Data System (ADS)

    Cazalilla, Miguel A.; Rey, Ana Maria

    2014-12-01

    We review recent experimental and theoretical progress on ultracold alkaline-earth Fermi gases with emergent SU(N) symmetry. Emphasis is placed on describing the ground-breaking experimental achievements of recent years. The latter include (1) the cooling to below quantum degeneracy of various isotopes of ytterbium and strontium, (2) the demonstration of optical Feshbach resonances and the optical Stern-Gerlach effect, (3) the realization of a Mott insulator of 173Yb atoms, (4) the creation of various kinds of Fermi-Bose mixtures and (5) the observation of many-body physics in optical lattice clocks. On the theory side, we survey the zoo of phases that have been predicted for both gases in a trap and loaded into an optical lattice, focusing on two and three dimensional systems. We also discuss some of the challenges that lie ahead for the realization of such phases such as reaching the temperature scale required to observe magnetic and more exotic quantum orders. The challenge of dealing with collisional relaxation of excited electronic levels is also discussed.

  16. Quantum transport in ultracold atoms

    NASA Astrophysics Data System (ADS)

    Chien, Chih-Chun; Peotta, Sebastiano; di Ventra, Massimiliano

    2015-12-01

    Ultracold atoms confined by engineered magnetic or optical potentials are ideal to study phenomena otherwise difficult to realize or probe in the solid state, thanks to the ability to control the atomic interaction strength, number of species, density and geometry. Here, we review quantum transport phenomena in atomic gases that mirror and can either better elucidate or show fundamental differences with respect to those observed in mesoscopic and nanoscopic systems. We discuss the significant progress in transport experiments in atomic gases, the similarities and differences between transport in cold atoms and in condensed matter systems, and survey theoretical predictions that are difficult to verify in conventional set-ups.

  17. Measurement-induced control with a nondestructive quantum gas microscope

    NASA Astrophysics Data System (ADS)

    Jung, Minwoo; Madjarov, Ivaylo S.; Rabinowitz, Jacob; Wellner, Zoe; Chen, Huiyao Y.; Cheung, Hil F. H.; Patil, Yogesh Sharad; Vengalattore, Mukund

    2016-05-01

    The physics of ultracold lattice gases has expanded from understanding Hubbard models to a much broader set of questions of nonequilibrium quantum dynamics, quantum thermodynamics, manybody entanglement, etc. These studies are increasingly being enabled by the advent of quantum gas microscopy, i.e. acquiring in-situ real space information, that is gaining prominence as a very powerful technique to study lattice gases. Nonetheless, the realization of fascinating correlated manybody states requires prohibitively low temperatures and entropies, far below what can be accessed through conventional evaporative cooling. The combination of quantum gas microscopy and measurement based quantum control offers an alternate route to state preparation of lattice gases in regimes of strong correlations. In this poster, we present our ongoing work on using site resolved imaging for the preparation of correlated manybody phases. This work is supported by the ARO MURI on non-equilibrium dynamics.

  18. Mechanical equivalent of quantum heat engines.

    PubMed

    Arnaud, Jacques; Chusseau, Laurent; Philippe, Fabrice

    2008-06-01

    Quantum heat engines employ as working agents multilevel systems instead of classical gases. We show that under some conditions quantum heat engines are equivalent to a series of reservoirs at different altitudes containing balls of various weights. A cycle consists of picking up at random a ball from one reservoir and carrying it to the next, thereby performing or absorbing some work. In particular, quantum heat engines, employing two-level atoms as working agents, are modeled by reservoirs containing balls of weight 0 or 1. The mechanical model helps us prove that the maximum efficiency of quantum heat engines is the Carnot efficiency. Heat pumps and negative temperatures are considered. PMID:18643212

  19. Filter for cleaning hot gases

    SciTech Connect

    Gresch, H.; Holter, H.; Hubner, K.; Igelbuscher, H.; Weber, E.

    1981-10-20

    In an apparatus for cleaning hot gases a filter housing has an inlet for unfiltered gas and an outlet for filtered gas. A plurality of filtered inserts are placed within the housing in a manner capable of filtering undesirable components from the gas feed stream. Each filter insert is made of a fibrous filter material. Silicic-acid glass fibers have a silicic acid content of at least 90%. Coated upon the fibers and absorbed into their pores is a metal oxide of aluminum, titanium, zirconium, cromium, nickle or cobalt. A honeycombed cage filled with high temperature resistant perlite is located within the housing between the gas inlet and the fiber inserts. The cage has an inlet and outlet external to the housing for replacing the perlite. A combustion chamber mounted in the housing has a discharge nozzle located so that the nozzle is directed at the filter inserts. Combusting materials in the chamber causes an explosive backflow of gases through the filter inserts.

  20. Predicting Flows of Rarefied Gases

    NASA Technical Reports Server (NTRS)

    LeBeau, Gerald J.; Wilmoth, Richard G.

    2005-01-01

    DSMC Analysis Code (DAC) is a flexible, highly automated, easy-to-use computer program for predicting flows of rarefied gases -- especially flows of upper-atmospheric, propulsion, and vented gases impinging on spacecraft surfaces. DAC implements the direct simulation Monte Carlo (DSMC) method, which is widely recognized as standard for simulating flows at densities so low that the continuum-based equations of computational fluid dynamics are invalid. DAC enables users to model complex surface shapes and boundary conditions quickly and easily. The discretization of a flow field into computational grids is automated, thereby relieving the user of a traditionally time-consuming task while ensuring (1) appropriate refinement of grids throughout the computational domain, (2) determination of optimal settings for temporal discretization and other simulation parameters, and (3) satisfaction of the fundamental constraints of the method. In so doing, DAC ensures an accurate and efficient simulation. In addition, DAC can utilize parallel processing to reduce computation time. The domain decomposition needed for parallel processing is completely automated, and the software employs a dynamic load-balancing mechanism to ensure optimal parallel efficiency throughout the simulation.