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Prior work has established the existence of a color-performance relationship in achievement contexts and has demonstrated its presence in some undergraduate course examinations. This study examines the manifestation of such a relationship in an introductory, 430-student, calculus-based electricity and magnetism course during which the paper color used in examinations was varied. In this report, we analyze three separate exams and differentiate between students’ multiple choice, written response, conceptual, and computational performances. Also considered are factors such as the time students require to complete exams and their confidence levels prior to and immediately following assessment. Performance in all categories appears to be independent of paper color.

Deviations of the electron function velocity distribution from Maxwellian behavior in the high energy range have been extensively studied during the past two decades. A brief review of the experimental techniques and findings on the subject is given in this paper. There are indications that the electron distribution function in thermonuclear plasmas could be significantly different from the Maxwellian one even near the thermal velocity range when particular circumstances occur. These reasons motivate a renewed effort in the measurements that could detect low energies distortions, among which is the new Oblique Electron Cyclotron Emission diagnostics that has entered operations during 2006 experimental campaign at JET and aims to resolve relatively small differences in the ECE spectra taken at three toroidal angles. Such measurements allow insight into the characteristics of the electron distribution function. First results of such experimental system are discussed in this paper, along with emission simulations.

In the 1933 Bohr and Rosenfeld’s famous article on electromagnetic field measurements they did not consider the measurement of a magnetic component in a given space‐time region, nor the measurement of two parallel magnetic components, nor the measurement of two non‐parallel magnetic components, nor the parallel measurement of one magnetic and one electric component, nor the non‐parallel measurement of one electric and one magnetic component, nor the non‐parallel measurement of one magnetic and one electric component in two different space‐time regions. This article covers the first one of these pending matters.

When the atomic physicist measures or computes, applications of their results may not be immediately obvious. However, atomic data form the basis of many mature and developing applications. Two of these applications and their dependence on data are reviewed here. In particular, the national standard for radiation exposure and the processing of the United States mail with radiation are discussed.

Solar flares provide a unique site for the study of energy release and particle acceleration in astrophysics. This paper summarizes the charged particle and gamma ray aspects of the Workshop on High Energy Solar Physics held at the Goddard Space Flight Center in August 1995. The X‐ray aspects of the Workshop are summarized in another paper. Here are our highlights: (i) both the charged particle, and now also gamma ray observations have shown that stochastic acceleration due to gyroresonant interactions with plasma waves is very important in solar flares; (ii) CME driven shocks accelerate the particles observed in space from gradual flares; (iii) accelerated MeV/nucl ions can contain a large fraction of the energy released in flares; (iv) GeV ions are either trapped at the Sun or accelerated for hours; (v) nuclear gamma ray spectroscopy has become a tool for abundance determinations in the solar atmosphere; (vi) behind‐the‐limb flares can provide imaging information for solar gamma ray emission.

In this short paper we show the existence of solitonic solutions of four dimensional ungauged N = 1 supergravity coupled to arbitrary vector and chiral multiplets whose Ricci scalar curvature is constant. The Ricci scalar of spacetimes indeed depends on the σ‐model, namely the complex scalars and their first derivative. Then, we give two explicit models, namely static domain walls and static spherical symmetric black holes which are related to our previous works.

D meson 3‐body hadronic decay data in the past were analyzed with Breit‐Wigner amplitude fits. However, the complicated dynamics of the final states is known from previous studies to be poorly described by Breit‐Wigner models. This short paper discusses work within CLEO to use coupled channel techniques to describe these decays.

We summarize some current research on the formation and evolution of the universe and overview some of the key questions surrounding the the big bang. There are really only two observational cosmological probes of the physics of the early universe. Of those two, the only probe during the relevant radiation dominated epoch is the yield of light elements during the epoch of big bang nucleosynthesis. The synthesis of light elements occurs in the temperature regime from 108 to 1010 K and times of about 1 to 104 sec into the big bang. The other probe is the spectrum of temperature fluctuations in the CMB which (among other things) contains information of the first quantum fluctuations in the universe, along with details of the distribution and evolution of dark matter, baryonic matter and photons up to the surface of photon last scattering. Here, we emphasize the role of these probes in answering some key questions of the big bang and early universe cosmology.

This paper deals with the mathematical framework of near-field acoustic holography based on finite elements in application to the acoustic response of a fluid within a closed cavity to the enclosure boundary conditions. The finite element method is an effective implementation of the modal approach for arbitrary geometries and provides advantages for certain wavenumber intervals in rooms. An inverse implementation of the direct problem can benefit from using generalized coordinates with modally reduced system matrices. A solution can be obtained via singular value decomposition together with Tikhonov regularization. This paper investigates acoustic mode spectrums of acoustic transfer functions, which has a major effect on the reconstruction of particle velocities from given sound pressures in a simple cavity model. It is found that the largest considered modal wavenumber in the acoustic transfer matrix should be twice the maximum excitation wavenumber. Furthermore, the relation between reconstruction errors and the detectability of evanescent waves depending on the wavenumber of excitation is considered. The proposed method is validated experimentally by reconstructing particle velocities on the inner boundaries of an Airbus A400M fuselage based on measurements of the inner pressure field. Results are compared with structural velocities measured with a laser Doppler vibrometer.

The Impulse Response (IR) method is a well-established form of non-destructive testing (NDT) where the dynamic response of an element resulting from an impact event (hammer blow) is measured with a geophone to make conclusions about the element’s integrity, stiffness, and/or support conditions. The existing ASTM Standard C1740-10 prescribes a set of parameters that can be used to evaluate the conditions above. These parameters are computed from the so-called ‘mobility’ spectrum which is obtained by dividing the measured bridge deck response by the measured impact force in the frequency domain. While applying the test method in the laboratory as well as on an actual in-service concrete bridge deck, the authors of this paper observed several limitations that are presented and discussed in this paper. In order to better understand the underlying physics of the IR method, a Finite Element (FE) model was created. Parameters prescribed in the Standard were then computed from the FE data and are discussed. One main limitation appears to be the use of a fixed upper frequency of 800 Hz. Test data from the real bridge deck as well as the FE model both show that most energy is found above that limit. This paper presents and discusses limitations of the ASTM Standard found by the authors and suggests ways for improving it.

Non-equilibrium Green function formulism and equation of motion approach has been used to study the electron transport through coupled quantum dot (CQD) system in the presence of intra-dot coulomb interaction. With focus on quantum interference, an obvious Fano interference is readily observed in the conduction spectrum of CQD system. In this paper the possibility of manipulating the Fano line shape in the tunneling spectra of CQD system is being explored by tuning the magnetic flux threading the CQD system and leads. The role of asymmetric coupling during transition from series configuration to parallel one is observed to be magnetic flux dependent. Absence of Fano effect in series CQD system and presence of Fano effect in the symmetric parallel CQD in the presence of magnetic flux is the main hallmark of this paper.

The present paper theoretically constructs the proton temperature anisotropy versus beta distribution by means of quasi-linear theory. It is shown that the simulated solar wind data distribution is constrained by the apparent mirror and oblique fire-hose marginal instability curves, which is consistent with observation. To achieve this closure, it is note that the actual magnetic field intensity near 1 AU is characterized intermediate-scale temporal variations. Making use of this fact, the present paper carries out the quasi-linear analysis of the temperature anisotropy-driven instabilities with adiabatically time-varying B field. This prescription successfully leads to the superficial mirror and oblique marginal instability constraints for the proton anisotropy, thus providing a possible explanation for the observation.

The nucleosynthesis of 31P in stars of 30 M⊙ model with solar metallicity is investigated using the MESA (Modules for Experiments in Stellar Astrophysics) stellar evolution code. Mass loss mechanisms are included in the evolution of the star with no rotation. The mass loss mechanism used is one constructed by MESA. The paper is divided into two parts. The first part deals with the investigations of the main reactions involved in the production and destruction of 31P. The site for the nucleosynthesis of 31P is also suggested. In the second part of the paper we compare the results of our production of 31P to other papers whenever possible and discuss the need to add new reactions to the network. We also explore the possible mechanisms for the distribution of 31P to the galaxy.

This paper presents a numerical study of a low Reynolds number flow around a thick airfoil (Eppler's E863 airfoil) with and without an upper-surface vortex-trapping cavity. The numerical model of flow is constructed using an O-grid computational domain around the airfoil and analyzed using four different turbulence models: namely standard k-e, RNG k-e, SST k-ω and the one-equation Spallart-Almaras (SA). Enhance wall treatment is employed for the two-equation turbulence models with the non-dimensional first cell height y+ at the wall region kept close to 1. The Reynolds number is kept constant at 354000. Results of lift & drag coefficient as well as velocity profiles are presented for four different angles of attack from 0 to 15 deg. The RNG k-e model is found to better predict the flow field and airfoil lift and drag characteristics as compared to the other turbulence models taken into consideration in this paper. The presence of the vortex-trapping cavity midway on the upper-surface of the airfoil is fou...

This paper summarizes the activities and the discussion of Working Group 5 at the Advanced Accelerator Conceopts Workshop held in Austin, Texas, in June 2012. The themes of this working group are very broad and we have regrouped the sessions and discussions, as well as the organization of this paper, in four general topics: electron sources, phase space manipulation, diagnostics and radiation generation. Within the latter, ampler space was given to beam-based radiation sources in the spectral range where conventional light sources perform poorly, that includes the THz window and the high energy end of the electromagnetic spectrum (x-rays and γ-rays).

This paper comprises two separate parts. First, we present the high-spin states in 139Pm nucleus. Two negative-parity dipole bands have been observed and assigned as πh11/2⊗ν(h11/2)−2 and πh11/2⊗ν(h11/2)−4 configurations. From the systematic comparison with neighboring nuclei and SPAC (Shears mechanism with Principal Axis Cranking) model calculations, the two bands can be suggested as magnetic rotational bands. In the other part of this paper, the construction of one new array of eight Clover and sixteen HPGe detectors has been introduced. The characteristics of the Clover detector have been presented and compared with Geant4 simulations.

A 1d Boltzmann equation is introduced to describe the speed distribution function in granular gas system with local collision dissipation. It leads to introduce a new term, equivalent to an acceleration This term was always assumed to be 0, but it is not zero in general, even when the system is steady (i.e. when local mean flow equals 0). This shows that the flow (+ boundary) exerts a force on any extra steady particle (or plane) that drives it to the center. This result is analyzed, compared and interpreted using the Lagrangian & Eulerian view points of the mechanics; it demonstrates that classic view point of hydrodynamics does not hold anymore. The paper investigates different cases and gives experimental evidences of the features: it explains while local speed distribution f(v,r) of granular gas in a box subjected to vibration is non symmetric in the direction of vibration, while the system is stationary (mean local speed equals 0). Papers giving local experimental or simulated distributions are quote...

As a result of recent advances in both atomic theory and experiment, The isotope shift method now stands as the method of choice for the determination of nuclear charge radii in light few-electron atoms, and it provides a unique measurement tool for the study of exotic “halo” nuclei. This paper reviews the high precision variational techniques used to solve the nonrelativistic Schrodinger equation for two- and three-electron atoms, and the calculation of relativistic and quantum electrodynamic (QED) contributions to the isotope shift. Sample results are given for the isotopes 3He and 6He relative to 4He, and 11Li relative to 7Li. A remarkably simple systematic behavior of the QED shift (Bethe logarithm) is discussed. A companion paper by W. Nortershauser discusses further the experimental techniques and results for the charge radius of halo nuclei.

The standard model implies the energy and momentum conservation law and the Higgs boson existence. Thus, the violation of the conservation law implies the violation of the standard model and its implications. Object of this paper is to describe the experimental verification of a self-propulsive force created by means of a superconducting device. This device is a converging nozzle made of a superconductor like YBCO and two permanent magnets, acting as a self-propulsion mechanism with direction towards the converging area. This device is activated when it is immersed within a coolant as the liquid Nitrogen. The force is measured through the slope of a pendulum created by the device mentioned hanged by means of a string from a constant point. This self propulsion violates the conservation law and requires beyond the standard model. Through logic analysis and by means of a theorem, stating the contradictory nature of communication, we can reach the minimum contradictions physics; according to this physics space-time is quantumstochastic and matter itself; there are (g)-mass and (em)-charge space-time which interact-communicate through photons [(g) or (em) particles with zero rest mass]. A quick explanation, of the experiment mentioned, is given by means of the minimum contradictions physics; this physics can imply the neutron synthesis which has been experimentally verified and explained via Hadronic Mechanics by R. M. Santilli. Since, according to this, quantum space time is matter itself there is not need for Higgs-implied by standard model-to exist; mass is a property of quantum space time itself. According to the CERN discovery there is a Higgs-like boson; according to this paper there is not the standard model Higgs boson.

Thermodynamic fluctuations are significant at microscopic scales even when hydrodynamic transport models (i.e., Navier-Stokes equations) are still accurate; a well-known example is Rayleigh scattering, which makes the sky blue. Interesting phenomena also appear in non-equilibrium systems, such as the enhancement of diffusion during mixing due to the correlation of velocity and concentration fluctuations. Direct Simulation Monte Carlo (DSMC) simulations are useful in the study of hydrodynamic fluctuations due to their computational efficiency and ability to model molecular detail, such as internal energy and chemical reactions. More recently, finite volume schemes based on the fluctuating hydrodynamic equations of Landau and Lifshitz have been formulated and validated by comparisons with DSMC simulations. This paper discusses some of the relevant numerical issues and physical effects investigated using DSMC and stochastic Navier-Stokes simulations. This paper also presents the multi-component fluctuating h...

The goal of this work is the investigation of the necessary conditions for the possible existence of tumbling in rotational motion of rigid bodies. In a stable spinning satellite, tumbling may occur by sufficient strong action of external impulses, when the conical movement characteristic of the stable attitude is de-characterized. For this purpose a methodology is chosen to simplify the study of rotational motions with great amplitude, for example free bodies in space, allowing an extension of the analysis to non-conservative systems. In the case of a satellite in space, the projection of the angular velocity along the principal axes of inertia must be known, defining completely the initial conditions of motion for stability investigations. In this paper, the coordinate systems are established according to the initial condition in order to allow a simple analytical work on the equations of motion. Also it will be proposed the definition of a parameter, calling it tumbling coefficient, to measure the intensity of the tumbling and the amplitude of the motion when crossing limits of stability in the concept of Lyapunov. Tumbling in the motion of bodies in space is not possible when this coefficient is positive. Magnus Triangle representation will be used to represent the geometry of the body, establishing regions of stability/instability for possible initial conditions of motion. In the study of nonconservative systems for an oblate body, one sufficient condition will be enough to assure damped motion, and this condition is checked for a motion damped by viscous torques. This paper seeks to highlight the physical understanding of the phenomena and the influence of various parameters that are important in the process.

In this paper we present an alternative perspective to physics expertise research. Using Lave and Wenger's theoretical perspective of Legitimate Peripheral Participation [4] as a guide to understanding expertise development, we redefine expertise from the perspective of physicists. We analyze data from an ethnographic, qualitative study of a physics research group and draw data from multiple sources to triangulate a definition of expert. Results show that a very critical part of becoming a physics expert in this physics research group is communicating one's scientific ideas through writing. Students perceive scientific writing as an important aspect of participating in the research group and it is a significant discussion point in the research meetings. Thus, it appears that learning to write a scientific paper is a process congruent to developing physics expertise.

In traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems of physical acoustics. Ultrasonic waves in liquids are mostly seen as scalar waves of acoustic pressure accompanied by fluid particle velocity. No waves are considered in which velocity is accompanied by pressure. The paper proves the existence and fundamental role of both waves, presenting two distinct spherical wavefields induced by two kinds of point mechanical disturbances. A detailed phenomenological synthesis of linear acoustic field equations followed by an analysis of their solutions performed directly in the time domain, gives two classes of results, showing that the fields of scalar and vector sources, although formally twin, are much different, especially in the immediate vicinity of sources. This difference should not be neglected in precise ultrasonics.

In a recent paper [1] the 1S0 pairing gap in isospin-symmetric nuclear matter and finite nuclei has been investigated starting from the chiral nucleon-nucleon potential at the N3LO order in the two-body sector and the N2LO order in the three-body sector. To include realistic nuclear forces in RHB (Relativistic Hartree Bolgoliubov) calculations we relied on a separable representation of the pairing interaction. In this paper we would like to show recent results concerning isotonic chains with N = 28,50,82.

The key difference between equilibrium (thermal) and non-equilibrium (low temperature – a.k.a. cold) plasmas is in the degree in which the shape of the cross sections influences the electron energy distribution function (EEDF). In this paper we will discuss the issue of kinetic phenomena from two different angles. The first will be how to take advantage of the strong influence and use low current data to obtain the cross sections. This is also known as the swarm technique and the product of a “swarm analysis” is a set of cross sections giving good number, momentum and energy balances of electrons or other charged particles. At the same time understanding the EEDF is based on the cross section data. Nevertheless sometimes the knowledge of the cross sections and even the behaviour of individual particles are insufficient to explain collective behaviour of the ensemble. The resulting “kinetic” effects may be used to favour certain properties of non-equilibrium plasmas and even may be used as the basis of some new plasma applications.The key difference between equilibrium (thermal) and non-equilibrium (low temperature – a.k.a. cold) plasmas is in the degree in which the shape of the cross sections influences the electron energy distribution function (EEDF). In this paper we will discuss the issue of kinetic phenomena from two different angles. The first will be how to take advantage of the strong influence and use low current data to obtain the cross sections. This is also known as the swarm technique and the product of a “swarm analysis” is a set of cross sections giving good number, momentum and energy balances of electrons or other charged particles. At the same time understanding the EEDF is based on the cross section data. Nevertheless sometimes the knowledge of the cross sections and even the behaviour of individual particles are insufficient to explain collective behaviour of the ensemble. The resulting “kinetic” effects may be used to favour certain properties of non-equilibrium plasmas and even may be used as the basis of som...

This paper is a short introduction on the analysis of the concepts of field in physics, showing their different natures. It comprises a study on the development of observers based on observational realism, a physical epistemology in development, on the basis of analytical psychology. This epistemology incorporates and justify the proposition of R. Carnap, of separating observational and theoretical domains of a theory, and gives a criterion for this separation. The basis of three theories are discussed, where concepts of field emerge. We discuss the different origins and meanings of these fields, from an epistemological point of view, in their respective theories. The aim of this paper is to form a basis of discussion to be applied in the analysis of other theories where concepts of field are present, to reach a better understanding of the contemporary programs of unification. We would like to clarify if these programs are intended for unification of fields as elements of the physical reality, fields as explanations for the observations, unification of their theories, or other possible cases.

The Tropospheric Emission Spectrometer (TES) instrument pulse tube cryocoolers began operation 36 days after launch of the NASA Earth Observing System (EOS) Aura spacecraft on July 15, 2004. TES is designed with four infrared Mercury Cadmium Telluride focal plane arrays in two separate housings cooled by a pair of Northrup Grumman Aerospace Systems (NGAS) single-stage pulse tube cryocoolers. The instrument also makes use of a two-stage passive cooler to cool the optical bench. The instrument is a high-resolution infrared imaging Fourier transform spectrometer with 3.3-15.4 micron spectral coverage. After four weeks of outgassing, the instrument optical bench and focal planes were cooled to their operating temperatures to begin science operations. During the early months of the mission, ice contamination of the cryogenic surfaces including the focal planes led to increased cryocooler loads and the need for periodic decontamination cycles. After a highly successful 5 years of continuous in-space operations, TES was granted a 2 year extension. This paper reports on the TES cryogenic system performance including the two-stage passive cooler. After a brief overview of the cryogenic design, the paper presents detailed data on the highly successful space operation of the pulse tube cryocoolers and instrument thermal design over the past six years since the original turn-on in 2004. The data shows the cryogenic contamination decreased substantially to where decontamination cycles are now performed every six months. The cooler stroke required for constant-temperature operation has not increased indicating nearconstant cooler efficiency and the instrument's thermal design has also provided a nearly constant heat rejection sink. At this time TES continues to operate in space providing important Earth science data. KEYWORDS: TES, EOS, Aura, cryocooler

Since the early'70s AWE has focussed on indirect drive as a means of accessing high energy density regimes. We give a brief historical perspective of this work and the rationale for the construction of the ORION laser. This laser is currently in commissioning and is scheduled to commence experiments in 2012. The ORION laser is configured to provide long pulses (~ 1ns) with a high degree of pulse shape flexibility, together with synchronised short pulse (~1ps) irradiation. The paper describes how this combination should enable pressures in excess of 1 Gb and temperatures of greater than 500 eV to be achieved. The ability to access and diagnose such conditions has applications in many fields; examples are given in planetary science, astrophysics and inertial fusion energy. For these applications we first describe the approach to measuring equation of state and opacity properties in the high energy density regime. Such properties are then incorporated into integrated computer simulation codes and validated against laser experiments, some of which have been conducted recently at the OMEGA laser at the University of Rochester. The paper concludes with a discussion of inertial fusion energy and the new high energy density regimes that this would access, if successful.

This paper is offered as a response to the remarks regarding [1], as given in [2].This paper is offered as a response to the remarks regarding [1], as given in [2].

Ions with energies above the plasma ion temperature (also called super thermal, hot or energetic particles - EP) are utilized in laboratory experiments as a plasma heat source to compensate for energy loss. Sources for super thermal ions are direct injection via neutral beams, RF heating and fusion reactions. Being super thermal, ions have the potential to induce instabilities of a certain class of magnetohydrodynamics (MHD) cavity modes, in particular, various Alfven and Alfvenacoustic Eigenmodes. It is an area where ideal MHD and kinetic theories can be tested with great accuracy. This paper touches upon key motivations to study the energetic ion interactions with MHD modes. One is the possibility of controlling the heating channel of present and future tokamak reactors via EP transport. In some extreme circumstances, uncontrolled instabilities led to vessel wall damages. This paper reviews some experimental and theoretical advances and the developments of the predictive tools in the area of EP wave int...

This paper describes industrial charged particle beamline technologies and design approaches. Beamlines accommodate myriad constraints in the radioisotope production, electron beam processing, and ion implantation market segments, and some very strange yet interesting solutions result. In this paper, a detailed look at a particular injection beamline solution gives some sense of the complexity of research and development required, and the sophistication of the beamline solutions that are utilized. A brief review of beamline applications in each industrial segment follows.

Since last two decades free‐space optical communication (FSO) has become more and more interesting as an alternative to radio frequency communication. This paper gives an overview of the power budget of an FSO system, designer has to consider while designing an FSO link. In this paper we have calculated the power needed for the transmission of a signal in free space. The received power and distance graph shows that more power needed when the link distances increases; also power and Bit Rate graph obtained at a distance 500 meter. In order to evaluate the power vs. Bit Rate graph we consider a link of distance 500 meter, optical window 1550 nm and three different atmospheric condition 10 dB/Km, 40 dB/Km and 60 dB/Km. The VCSEL laser is used for direct line of sight communication and at the receiver side the APD is used for power reception. The NRZ–OOK modulation format is used for laser beam modulation.

This paper is devoted to the numerical approximation of the ionospheric Dynamo model in a non‐uniform magnetic field. The numerical difficulty to solve this model comes from the anisotropy of the elliptic equation describing the electric field. This anisotropy causes the associated linear system of elliptic equation to be ill‐conditioned, when solved with standard methods. We present an asymptotic preserving method in this paper to solve this anisotropic equation, such that its linear system is independent of the anisotropy.

In this paper we compare and contrast the effects of longitudinal coupling and temporal delay on a fluid‐structure transmission‐line model of the mammalian cochlea. This work is based on recent reports that, in order to qualitatively explain experimental data, models of the basilar membrane impedance must include an exponential term that represents a time‐delayed feedback. There are also models that include, e.g., a spatial feed‐forward mechanism, whose solution is often approximated by replacing the feed‐forward coupling by an exponential term. We show that there is no direct equivalence between the time‐delay and the longitudinal coupling mechanisms, although qualitatively similar results can be achieved, albeit in very different regions of parameter space. An investigation of the steady‐state outputs shows that both models can display sharp tuning, but that the time‐delay model requires negative damping for such an effect to occur. Conversely, the longitudinal coupling model provides the most promising results with small positive damping. These results are extended by a careful stability analysis. We find that, whereas a small time delay can stabilize an unstable transmission‐line model (with negative damping), that the longitudinal coupling model is stable when the damping is positive. The techniques developed in the paper are directed towards a more comprehensive analysis of nonlinear models.In this paper we compare and contrast the effects of longitudinal coupling and temporal delay on a fluid‐structure transmission‐line model of the mammalian cochlea. This work is based on recent reports that, in order to qualitatively explain experimental data, models of the basilar membrane impedance must include an exponential term that represents a time‐delayed feedback. There are also models that include, e.g., a spatial feed‐forward mechanism, whose solution is often approximated by replacing the feed‐forward coupling by an exponential term. We show that there is no direct equivalence between the time‐delay and the longitudinal coupling mechanisms, although qualitatively similar results can be achieved, albeit in very different regions of parameter space. An investigation of the steady‐state outputs shows that both models can display sharp tuning, but that the time‐delay model requires negative damping for such an effect to occur. Conversely, the longitudinal coupling model provides the most promising...

Numerical simulations and control of tail‐swaying swim of three‐dimensional biomimetic fish in a viscous flow and the vorticity dynamics of fish swimming have been investigated in this paper, with a computational fluid dynamics package, which combines the adaptive multi‐grid finite volume method and the methods of immersed boundary and volume of fluid, and the control strategy of fish motion. Using boundary vorticity‐flux (BVF) theory, we have studied the mechanism of fish swimming and trace the physical root to the moving body surface. With the change of swimming speed, the effects of fish body and caudalfin on thrust, is analysed quantitatively. Finally the relationship between the forces exerted on fish body and vortex structures of fish swimming has been presented in this paper.

A single dielectric barrier discharge is a specific configuration for plasma actuators consisting of two electrodes, one coated by a dielectric material and the other is exposed to the air. The purpose of this paper is to study the characteristics of single dielectric barrier discharge (DBD) plasma actuator through numerical modeling. A mathematical model that represents the physical system is presented and the numerical simulations for specific geometry are discussed in this paper. With this model, we can study the physics of the plasma flow. The formulation of the governing equations are divided into two since the physical system can be distinctly separated; one is the electrostatic part and the other is on the fluid flow. The electrostatic part is formulated using the Maxwell’s equation which needs to be modified to incorporate the current frequency equation so that the system of equations becomes unsteady which is more realistic compared to a steady system of equations. The fluid flow part is formulated using the Navier-Stokes equations. The equations are re-represented using a vorticity term and stream function so that the flow characteristics can be clearly visualized. All equations are discretized using finite difference method. The discretized equations are then solved using the Gauss-Seidel iteration method. The numerical results show that the vorticity of the plasma is similar in pattern at each time interval. The highest magnitude of the vorticity occurs at the inner part near end of the upper electrode but this magnitude is different at each time. On varying the applied voltage, it is found that the peak vorticity also increases. Therefore, this shows that both the applied voltage and the geometry of the system influence the characteristics of the plasma flow.

To the student of thermodynamics the most difficult subject is entropy. In this paper we examine the actual, practical application of entropy to two simple systems, the homogeneous slab with fixed boundary values of the temperature, and an isolated atmosphere in the presence of the static gravitational field. The first gives valuable insight into the nature of entropy that is subsequently applied to the second system. It is a basic tenet of thermodynamics that the equilibrium of an extended, homogeneous and isolated system is characterized by a uniform temperature distribution and it is a strongly held belief that this remains true in the presence of gravity. We find that this is consistent with the equations of extended thermodynamics but that entropy enters in an essential way. The principle of equivalence takes on a new aspect., Paper presented the AIP Conference on the second law of thermodynamics, June 2011. Plaintex 20 pages

We show that the pseudospin symmetry that Akito Arima discovered many years ago (with collaborators) is a symmetry of the the Dirac Hamiltonian for which the sum of the scalar and vector potentials are a constant. In this paper we discuss some of the implications of this relativistic symmetry and the experimental data that support these predictions. In his original paper Akito also discussed pseudo-U(3) symmetry. We show that pseudo-U(3) symmetry is a symmetry of the Dirac Hamiltonian for which the sum of harmonic oscillator vector and scalar potentials are equal to a constant, and we give the generators of pseudo-U(3) symmetry. Going beyond the mean field we summarize new results on non relativistic shell model Hamiltonians that have pseudospin symmetry and pseudo-orbital angular momentum symmetry as a dynamical symmetries.

The crucial point of the paper is the relation between equilibrium distributions of plasma species and the type of propagation or diffusive transition of plasma response to a disturbance. The paper contains a unified treatment of disturbance propagation (transport) in the linearized Vlasov electron‐positron and fullerene pair plasmas containing charged dust impurities, based on the space‐time convolution integral equations. Electron‐positron‐dust/ion (e‐p‐d/i) plasmas are rather widespread in nature. Space‐time responses of multi‐component linearized Vlasov plasmas on the basis of multiple integral equations are invoked. An initial‐value problem for Vlasov‐Poisson/Ampere equations is reduced to the one multiple integral equation and the solution is expressed in terms of forcing function and its space‐time convolution with the resolvent kernel. The forcing function is responsible for the initial disturbance and the resolvent is responsible for the equilibrium velocity distributions of plasma species. By us...

Activation analysis can be performed using three different techniques, namely: activation with neutrons, with high‐energy photons, and with charged particles. The different features as well as the advantages and drawbacks of these separate techniques will be discussed in this paper. During exposure radionuclides are produced in the activated sample and, the turn, the radiation emitted during radioactive decay (photons in the most cases) is measured with appropriate spectrometers. By evaluating the produced spectra, the elemental components of the activated material can be quantitatively ascertained. Through means of activation analysis, basically any kind of material can be studied. And frequently the sample can be analysed as is (instrumentally without complicated radiochemical separation steps), and in favourable cases, the analysis may be conducted non‐destructively, i.e. without removing pieces of the interrogated sample. Several common applications will be discussed in this paper.

In the present paper an overview of the recent studies of a hypersonic laminar boundary layer and shock layer receptivity and stability are presented. Main attention is paid to investigations of nonlinear wave interaction. It is shown that nonlinear interactions of the second mode play significant role in laminar‐turbulent transition and intermode interaction is different for solid and porous walls. The paper deals with two different techniques of transition control. The first one, namely, ultrasonically absorptive coating (UAC) is a passive technique which uses porous materials on the wall to suppress growing acoustic disturbances in the boundary layer. The second one is based on wave interference and intermode interaction and uses blowing‐suction method to suppress acoustic in the boundary layer.

High intensity Accelerator is being studied all over world for numerous applications, which includes the waste transmutation, spallation neutron source and material irradiation facilities. The R/D activities of the technology of High intensity accelerator are also developed in China for some year, and have some good facilities around China. This paper will reports the status of some high intensity accelerators and neutron source in China, which including ADS/RFQ; CARR; CSNS; PKUNIFTY & CPHS. This paper will emphatically report the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China.

The ‘Herschel Space Observatory’ is the fourth cornerstone mission in the ‘Horizons 2000’ program of the European Space Agency (ESA), with the objectives to study the formation of galaxies in the early universe and the creation of stars. It will observe the chemical composition of surfaces and atmospheres of comets, planets and natural satellites, and examine the molecular chemistry of the universe. Herschel was launched into an operational Lissajous orbit around the Earth‐Sun L2 point by an Ariane 5 on May 14th 2009 to perform photometer and spectrometer measurements, covering the full far infrared to sub‐millimeter wavelength range from 60 to 670 micrometers during its operational lifetime of more than four years.This paper gives a short overview of the cryogenic system and summarises the cryogenic aspects of the different phases of the acceptance test campaign, including the launch preparation phase as well as the post‐launch transient cool‐down of the system, the verification of the Passive Phase Separator performance and the evaluation of pressure drop measurements performed on the helium venting system. The impact of thermo‐acoustic oscillations within the helium subsystem is described, which were present during the initial cool‐down test phase. A comparison of measurements to numerical analysis results is shown.The ‘Herschel Space Observatory’ is the fourth cornerstone mission in the ‘Horizons 2000’ program of the European Space Agency (ESA), with the objectives to study the formation of galaxies in the early universe and the creation of stars. It will observe the chemical composition of surfaces and atmospheres of comets, planets and natural satellites, and examine the molecular chemistry of the universe. Herschel was launched into an operational Lissajous orbit around the Earth‐Sun L2 point by an Ariane 5 on May 14th 2009 to perform photometer and spectrometer measurements, covering the full far infrared to sub‐millimeter wavelength range from 60 to 670 micrometers during its operational lifetime of more than four years.This paper gives a short overview of the cryogenic system and summarises the cryogenic aspects of the different phases of the acceptance test campaign, including the launch preparation phase as well as the post‐launch transient cool‐down of the system, the verification of the Passive Phase Sepa...

In this paper we will prove that the Lorentz factor doesn’t exist on the relative motion. In fact this factor is the result of a wrong calculation of Michelson. His mistake was approved by Lorentz and other physicists, including Einstein. Michelson in order to implement his idea with his interferometer in 1881, made the following mistake: he made the calculation according to the only principle of relativity which was known by physics—the Galileo principle, but he didn’t faithfully apply this principle. In this paper, the principle of Galileo will be implemented exactly to Michelson’s experiment and the result will show us that physics doesn’t need the postulates of the year 1905.

In this paper it is studied a relation between the kappa‐symmetric and pure spinor formulations of the supermembrane in eleven dimensions using Berkovits’ recently developed method for the superstring (in D = 10). In the present paper I present an extension of this method to the supermembrane, showing that it is possible to reinstate the reparameterization constraints in the pure spinor formulation of the supermembrane by introducing a topological sector and performing a similarity transformation. The resulting BRST charge is then of conventional type and is argued to be (related to) the BRST charge of the kappa‐symmetric supermembrane in a formulation where all second class constraints are “gauge unfixed” to first class constraints. In the present analysis a natural candidate for a (non‐covariant) supermembrane analogue of the superstring B‐ghost is encountered.

This paper revisits some content in the First International Symposium on Beamed Energy Propulsion in 2002 related to the concept of propellantless in‐space propulsion utilizing an external high energy laser to provide momentum to an ultralightweight (gossamer) spacecraft. The design and construction of the NanoSail‐D solar sail demonstration spacecraft has demonstrated in space flight hardware the concept of small, very light—yet capable—spacecraft. The results of the Joint High Power Solid State Laser (JHPSSL) have also increased the effectiveness and reduced the cost of an entry level laser source. This paper identifies the impact from improved system parameters on current mission applications.

This paper outlines the present status of the kinetic theory of turbulence in magnetized plasmas as being developed by the present author. The systematic program to formulate the theory of turbulence starting from the Vlasov‐Klimontovich formalism began with the works by pioneers of modern plasma physics in the 1960s and 1970s. However, early efforts adopted the heuristic semi‐classical method instead of the statistical mechanical formulation, which is necessary for a quantitative analysis. Recently, the present author picked up where the early pioneers left, and began to reformulate the kinetic turbulence theory of turbulence in magnetized plasmas from statistical mechanical formalism. This paper is a brief outline of the progress to date.

This paper sets out to develop a spider‐type multiple‐rotor system which can be used for attitude control of spacecraft. The multirotor system contains a large number of rotor‐equipped rays, so it was called a “Spider‐type System,” also it can be called “Rotary Hedgehog.” These systems allow using spinups and captures of conjugate rotors to perform compound attitude motion of spacecraft. The paper describes a new method of spacecraft attitude reorientation and new mathematical model of motion in Hamilton form. Hamiltonian dynamics of the system is investigated with the help of Andoyer‐Deprit canonical variables. These variables allow obtaining exact solution for hetero‐ and homoclinic orbits in phase space of the system motion, which are very important for qualitative analysis.

This paper is an abstract of a greater volume of work more than 30 years in formation. It is a thought experiment. In order to present certain concepts, statements are made without supporting scientific observations which would require a substantial manuscript to present. This paper defines a new fabric for space and hypothesizes that matter is formed from this fabric through the agency of Black Holes. Dark sound is theorized. As a consequence of this hypothesis a new model for the origin of the universe is given including new definitions for Black Holes, Dark Matter, and Dark Energy. Neutral electricity, cosmic planes and sub planes are defined. New processes for the coalescing of atoms, the rotation of planets and the observed phenomena of Cosmic Fire are given. Gravity is defined as the result of magnetism and chemical bonds between structures.