Brownian dynamics simulations of an order-disorder transition in sheared sterically stabilized colloidal suspensions

International Nuclear Information System (INIS)

Rigos, A.A.; Wilemski, G.

1992-01-01

The shear thinning behavior of a sterically stabilized nonaqueous colloidal suspension was investigated using nonequilibrium Brownian dynamics simulations of systems with 108 and 256 particles. At a volume fraction of 0.4, the suspension is thixotropic: it has a reversible shear thinning transition from a disordered state to an ordered, lamellar state with triangularly packed strings of particles. The time scale for the transition is set by the free particle diffusion constant. For the smaller system, the transition occurs gradually with increasing shear rate. For the larger system, the transition is sharp and discontinuous shear thinning is found. 34 refs., 9 figs., 1 tab

Higher-order (non-)modularity

DEFF Research Database (Denmark)

Appel, Claus; van Oostrom, Vincent; Simonsen, Jakob Grue

2010-01-01

We show that, contrary to the situation in first-order term rewriting, almost none of the usual properties of rewriting are modular for higher-order rewriting, irrespective of the higher-order rewriting format. We show that for the particular format of simply typed applicative term rewriting...... systems modularity of confluence, normalization, and termination can be recovered by imposing suitable linearity constraints....

Certified higher-order recursive path ordering

NARCIS (Netherlands)

Koprowski, A.; Pfenning, F.

2006-01-01

The paper reports on a formalization of a proof of wellfoundedness of the higher-order recursive path ordering (HORPO) in the proof checker Coq. The development is axiom-free and fully constructive. Three substantive parts that could be used also in other developments are the formalizations of the

Shear induced hexagonal ordering observed in an ionic viscoelastic fluid in flow past a surface

International Nuclear Information System (INIS)

Hamilton, W.A.; Butler, P.D.; Baker, S.M.; Smith, G.S.; Hayter, J.B.; Magid, L.J.; Pynn, R.

1994-01-01

We present the first clear evidence of a shear induced hexagonal phase in a polyionic fluid in flow past a plane quartz surface. The dilute surfactant solution studied is viscoelastic due to the formation and entanglement of highly extended charged threadlike micelles many thousands of A long, which are known to align along the flow direction under shear. Small-angle neutron diffraction data show that in the high shear region within a few tens of microns of the surface these micelles not only align, but form a remarkably well ordered hexagonal array separated by 370 A, 8 times their 46 A diameter

Higher Order Expectations in Asset Pricing

OpenAIRE

Philippe BACCHETTA; Eric VAN WINCOOP

2004-01-01

We examine formally Keynes' idea that higher order beliefs can drive a wedge between an asset price and its fundamental value based on expected future payoffs. Higher order expectations add an additional term to a standard asset pricing equation. We call this the higher order wedge, which depends on the difference between higher and first order expectations of future payoffs. We analyze the determinants of this wedge and its impact on the equilibrium price. In the context of a dynamic noisy r...

Geometrically nonlinear resonance of higher-order shear deformable functionally graded carbon-nanotube-reinforced composite annular sector plates excited by harmonic transverse loading

Science.gov (United States)

Gholami, Raheb; Ansari, Reza

2018-02-01

This article presents an attempt to study the nonlinear resonance of functionally graded carbon-nanotube-reinforced composite (FG-CNTRC) annular sector plates excited by a uniformly distributed harmonic transverse load. To this purpose, first, the extended rule of mixture including the efficiency parameters is employed to approximately obtain the effective material properties of FG-CNTRC annular sector plates. Then, the focus is on presenting the weak form of discretized mathematical formulation of governing equations based on the variational differential quadrature (VDQ) method and Hamilton's principle. The geometric nonlinearity and shear deformation effects are considered based on the von Kármán assumptions and Reddy's third-order shear deformation plate theory, respectively. The discretization process is performed via the generalized differential quadrature (GDQ) method together with numerical differential and integral operators. Then, an efficient multi-step numerical scheme is used to obtain the nonlinear dynamic behavior of the FG-CNTRC annular sector plates near their primary resonance as the frequency-response curve. The accuracy of the present results is first verified and then a parametric study is presented to show the impacts of CNT volume fraction, CNT distribution pattern, geometry of annular sector plate and sector angle on the nonlinear frequency-response curve of FG-CNTRC annular sector plates with different edge supports.

Order-sorted Algebraic Specifications with Higher-order Functions

DEFF Research Database (Denmark)

Haxthausen, Anne Elisabeth

1995-01-01

This paper gives a proposal for how order-sorted algebraic specification languages can be extended with higher-order functions. The approach taken is a generalisation to the order-sorted case of an approach given by Mller, Tarlecki and Wirsing for the many-sorted case. The main idea in the proposal...

Calibration Method to Eliminate Zeroth Order Effect in Lateral Shearing Interferometry

Science.gov (United States)

Fang, Chao; Xiang, Yang; Qi, Keqi; Chen, Dawei

2018-04-01

In this paper, a calibration method is proposed which eliminates the zeroth order effect in lateral shearing interferometry. An analytical expression of the calibration error function is deduced, and the relationship between the phase-restoration error and calibration error is established. The analytical results show that the phase-restoration error introduced by the calibration error is proportional to the phase shifting error and zeroth order effect. The calibration method is verified using simulations and experiments. The simulation results show that the phase-restoration error is approximately proportional to the phase shift error and zeroth order effect, when the phase shifting error is less than 2° and the zeroth order effect is less than 0.2. The experimental result shows that compared with the conventional method with 9-frame interferograms, the calibration method with 5-frame interferograms achieves nearly the same restoration accuracy.

Higher-Order Hierarchies

DEFF Research Database (Denmark)

Ernst, Erik

2003-01-01

This paper introduces the notion of higher-order inheritance hierarchies. They are useful because they provide well-known benefits of object-orientation at the level of entire hierarchies-benefits which are not available with current approaches. Three facets must be adressed: First, it must be po...

Origins of the anomalous stress behavior in charged colloidal suspensions under shear.

Science.gov (United States)

Kumar, Amit; Higdon, Jonathan J L

2010-11-01

Numerical simulations are conducted to determine microstructure and rheology of sheared suspensions of charged colloidal particles at a volume fraction of ϕ=0.33. Over broad ranges of repulsive force strength F0 and Péclet number Pe, dynamic simulations show coexistence of ordered and disordered stable states with the state dependent on the initial condition. In contrast to the common view, at low shear rates, the disordered phase exhibits a lower viscosity (μ(r)) than the ordered phase, while this behavior is reversed at higher shear rates. Analysis shows the stress reversal is associated with different shear induced microstructural distortions in the ordered and disordered systems. Viscosity vs shear rate data over a wide range of F0 and Pe collapses well upon rescaling with the long-time self-diffusivity. Shear thinning viscosity in the ordered phase scaled as μ(r)∼Pe(-0.81) at low shear rates. The microstructural dynamics revealed in these studies explains the anomalous behavior and hysteresis loops in stress data reported in the literature.

Lattice Boltzmann simulation of shear-induced particle migration in plane Couette-Poiseuille flow: Local ordering of suspension

Science.gov (United States)

Chun, Byoungjin; Kwon, Ilyoung; Jung, Hyun Wook; Hyun, Jae Chun

2017-12-01

The shear-induced migration of concentrated non-Brownian monodisperse suspensions in combined plane Couette-Poiseuille (C-P) flows is studied using a lattice Boltzmann simulation. The simulations are mainly performed for a particle volume fraction of ϕbulk = 0.4 and H/a = 44.3, 23.3, where H and a denote the channel height and radius of suspended particles, respectively. The simulation method is validated in two simple flows, plane Poiseuille and plane Couette flows. In the Poiseuille flow, particles migrate to the mid-plane of the channel where the local concentration is close to the limit of random-close-packing, and a random structure is also observed at the plane. In the Couette flow, the particle distribution remains in the initial uniform distribution. In the combined C-P flows, the behaviors of migration are categorized into three groups, namely, Poiseuille-dominant, Couette-dominant, and intermediate regimes, based on the value of a characteristic force, G, where G denotes the relative magnitude of the body force (P) against the wall-driving force (C). With respect to the Poiseuille-dominant regime, the location of the maximum concentration is shifted from the mid-plane to the lower wall moving in the same direction as the external body force, when G decreases. With respect to the Couette-dominant regime, the behavior is similar to that of a simple shear flow with the exception that a slightly higher concentration of particles is observed near the lower wall. However, with respect to the intermediate value of G, several layers of highly ordered particles are unexpectedly observed near the lower wall where the plane of maximum concentration is located. The locally ordered structure is mainly due to the lateral migration of particles and wall confinement. The suspended particles migrate toward a vanishingly small shear rate at the wall, and they are consequently layered into highly ordered two-dimensional structures at the high local volume fraction.

Challenges in higher order mode Raman amplifiers

DEFF Research Database (Denmark)

Rottwitt, Karsten; Nielsen, Kristian; Friis, Søren Michael Mørk

2015-01-01

A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed......A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed...

HIGHER ORDER THINKING IN TEACHING GRAMMAR

Directory of Open Access Journals (Sweden)

Citra Dewi

2017-04-01

Full Text Available The aim of this paper discussed about how to enhance students’ higher order thinking that should be done by teacher in teaching grammar. Usually teaching grammar was boring and has the same way to learn like change the pattern of sentence into positive, negative and introgative while the students’ need more various way to develop their thinking. The outcome of students’ competence in grammar sometimes not sufficient enough when the students’ occured some test international standart like Test of English Foreign Language, International English Language Testing. Whereas in TOEFL test it needed higher order thinking answer, so teacher should develop students’ higher order thingking in daily teaching grammar in order to make the students’ enhance their thinking are higher. The method was used in this paper by using field study based on the experience of teaching grammar. It can be shown by students’ toefl score was less in stucture and written expression. The result of this paper was after teacher gave some treatments to enhance students’ higher order thinking in teaching grammar, the students’ toefl scores are sufficient enough as a part of stucture and written expression. It can concluded that it needed some strategies to enhancce students higher order thinking by teaching grammar it can make students’ higher toefl score. Teachers should be creative and inovative to teach the students’ started from giving the students’ question or test in teaching grammar.

Thermo-mechanical vibration analysis of a single-walled carbon nanotube embedded in an elastic medium based on higher-order shear deformation beam theory

International Nuclear Information System (INIS)

Ebrahimi, Farzad; Salari, Erfan

2015-01-01

In this study, the thermal effect on the free vibration characteristics of embedded Single-walled carbon nanotubes (SWCNTs) based on the size-dependent Reddy higher order shear deformation beam theory subjected to in-plane thermal loading is investigated by presenting a Navier-type solution and employing a semi-analytical Differential transform method (DTM) for the first time. In addition, the exact nonlocal Reddy beam theory solution presented here should be useful to engineers designing nanoelectromechanical devices. The small scale effect is considered based on nonlocal elasticity theory of Eringen. The nonlocal equations of motion are derived through Hamilton's principle, and they are solved by applying DTM. Numerical results reveal that the proposed modeling and semi-analytical approach can provide more accurate frequency results of the SWCNTs compared to analytical results and some cases in the literature. The detailed mathematical derivations are presented, and numerical investigations are performed, whereas emphasis is placed on investigating the effect of several parameters such as small-scale effects, boundary conditions, mode number, thickness ratio, temperature change, and Winkler spring modulus on the natural frequencies of the SWCNTs in detail. The vibration behavior of SWCNTs is significantly influenced by these effects. Results indicate that the inclusion of size effect results in a decrease in nanobeam stiffness and leads to a decrease in natural frequency. Numerical results are presented to serve as benchmarks for future analyses of SWCNTs.

Higher-Order Program Generation

DEFF Research Database (Denmark)

Rhiger, Morten

for OCaml, a dialect of ML, that provides run-time code generation for OCaml programs. We apply these byte-code combinators in semantics-directed compilation for an imperative language and in run-time specialization using type-directed partial evaluation. Finally, we present an approach to compiling goal......This dissertation addresses the challenges of embedding programming languages, specializing generic programs to specific parameters, and generating specialized instances of programs directly as executable code. Our main tools are higher-order programming techniques and automatic program generation....... It is our thesis that they synergize well in the development of customizable software. Recent research on domain-specific languages propose to embed them into existing general-purpose languages. Typed higher-order languages have proven especially useful as meta languages because they provide a rich...

Frontiers of higher order fuzzy sets

CERN Document Server

Tahayori, Hooman

2015-01-01

Frontiers of Higher Order Fuzzy Sets, strives to improve the theoretical aspects of general and Interval Type-2 fuzzy sets and provides a unified representation theorem for higher order fuzzy sets. Moreover, the book elaborates on the concept of gradual elements and their integration with the higher order fuzzy sets. This book also introduces new frameworks for information granulation based on general T2FSs, IT2FSs, Gradual elements, Shadowed sets and rough sets. In particular, the properties and characteristics of the new proposed frameworks are studied. Such new frameworks are shown to be more capable to be exploited in real applications. Higher order fuzzy sets that are the result of the integration of general T2FSs, IT2FSs, gradual elements, shadowed sets and rough sets will be shown to be suitable to be applied in the fields of bioinformatics, business, management, ambient intelligence, medicine, cloud computing and smart grids. Presents new variations of fuzzy set frameworks and new areas of applicabili...

Higher order harmonics of reactor neutron equation

International Nuclear Information System (INIS)

Li Fu; Hu Yongming; Luo Zhengpei

1996-01-01

The flux mapping method using the higher order harmonics of the neutron equation is proposed. Based on the bi-orthogonality of the higher order harmonics, the process and formulas for higher order harmonics calculation are derived via the source iteration method with source correction. For the first time, not only any order harmonics for up-to-3-dimensional geometry are achieved, but also the preliminary verification to the capability for flux mapping have been carried out

XY model with higher-order exchange.

Science.gov (United States)

Žukovič, Milan; Kalagov, Georgii

2017-08-01

An XY model, generalized by inclusion of up to an infinite number of higher-order pairwise interactions with an exponentially decreasing strength, is studied by spin-wave theory and Monte Carlo simulations. At low temperatures the model displays a quasi-long-range-order phase characterized by an algebraically decaying correlation function with the exponent η=T/[2πJ(p,α)], nonlinearly dependent on the parameters p and α that control the number of the higher-order terms and the decay rate of their intensity, respectively. At higher temperatures the system shows a crossover from the continuous Berezinskii-Kosterlitz-Thouless to the first-order transition for the parameter values corresponding to a highly nonlinear shape of the potential well. The role of topological excitations (vortices) in changing the nature of the transition is discussed.

Higher-Order Minimal Functional Graphs

DEFF Research Database (Denmark)

Jones, Neil D; Rosendahl, Mads

1994-01-01

We present a minimal function graph semantics for a higher-order functional language with applicative evaluation order. The semantics captures the intermediate calls performed during the evaluation of a program. This information may be used in abstract interpretation as a basis for proving...

Higher-Order Generalized Invexity in Control Problems

Directory of Open Access Journals (Sweden)

S. K. Padhan

2011-01-01

Full Text Available We introduce a higher-order duality (Mangasarian type and Mond-Weir type for the control problem. Under the higher-order generalized invexity assumptions on the functions that compose the primal problems, higher-order duality results (weak duality, strong duality, and converse duality are derived for these pair of problems. Also, we establish few examples in support of our investigation.

Neural classifiers for learning higher-order correlations

International Nuclear Information System (INIS)

Gueler, M.

1999-01-01

Studies by various authors suggest that higher-order networks can be more powerful and biologically more plausible with respect to the more traditional multilayer networks. These architecture make explicit use of nonlinear interactions between input variables in the form of higher-order units or product units. If it is known a priori that the problem to be implemented possesses a given set of invariances like in the translation, rotation, and scale invariant recognition problems, those invariances can be encoded, thus eliminating all higher-order terms which are incompatible with the invariances. In general, however, it is a serious set-back that the complexity of learning increases exponentially with the size of inputs. This paper reviews higher-order networks and introduces an implicit representation in which learning complexity is mainly decided by the number of higher-order terms to be learned and increases only linearly with the input size

Neural Classifiers for Learning Higher-Order Correlations

Science.gov (United States)

Güler, Marifi

1999-01-01

Studies by various authors suggest that higher-order networks can be more powerful and are biologically more plausible with respect to the more traditional multilayer networks. These architectures make explicit use of nonlinear interactions between input variables in the form of higher-order units or product units. If it is known a priori that the problem to be implemented possesses a given set of invariances like in the translation, rotation, and scale invariant pattern recognition problems, those invariances can be encoded, thus eliminating all higher-order terms which are incompatible with the invariances. In general, however, it is a serious set-back that the complexity of learning increases exponentially with the size of inputs. This paper reviews higher-order networks and introduces an implicit representation in which learning complexity is mainly decided by the number of higher-order terms to be learned and increases only linearly with the input size.

Effects of cyclic shear loads on strength, stiffness and dilation of rock fractures

Directory of Open Access Journals (Sweden)

Thanakorn Kamonphet

2015-12-01

Full Text Available Direct shear tests have been performed to determine the peak and residual shear strengths of fractures in sandstone, granite and limestone under cyclic shear loading. The fractures are artificially made in the laboratory by tension inducing and saw-cut methods. Results indicate that the cyclic shear load can significantly reduce the fracture shear strengths and stiffness. The peak shear strengths rapidly decrease after the first cycle and tend to remain unchanged close to the residual strengths through the tenth cycle. Degradation of the first order asperities largely occurs after the first cycle. The fracture dilation rates gradually decrease from the first through the tenth cycles suggesting that the second order asperities continuously degrade after the first load cycle. The residual shear strengths are lower than the peak shear strengths and higher than those of the smooth fractures. The strength of smooth fracture tends to be independent of cyclic shear loading.

An analytical study of the effects of transverse shear deformation and anisotropy on buckling loads of laminated cylinders. M.S. Thesis - George Washington Univ.

Science.gov (United States)

Jegley, Dawn C.

1987-01-01

Buckling loads of thick-walled orthotropic and anisotropic simply supported circular cylinders are predicted using a higher-order transverse-shear deformation theory. A comparison of buckling loads predicted by the conventional first-order transverse-shear deformation theory and the higher-order theory show that the additional allowance for transverse shear deformation has a negligible effect on the predicted buckling loads of medium-thick metallic isotropic cylinders. However, the higher-order theory predicts buckling loads which are significantly lower than those predicted by the first-order transverse-shear deformation theory for certain short, thick-walled cylinders which have low through-the-thickness shear moduli. A parametric study of the effects of ply orientation on the buckling load of axially compressed cylinders indicates that laminates containing 45 degree plies are most sensitive to transverse-shear deformation effects. Interaction curves for buckling loads of cylinders subjected to axial compressive and external pressure loadings indicate that buckling loads due to external pressure loadings are as sensitive to transverse-shear deformation effects as buckling loads due to axial compressive loadings. The effects of anisotropy are important over a much wider range of cylinder geometries than the effects of transverse shear deformation.

Higher order antibunching in intermediate states

International Nuclear Information System (INIS)

Verma, Amit; Sharma, Navneet K.; Pathak, Anirban

2008-01-01

Since the introduction of binomial state as an intermediate state, different intermediate states have been proposed. Different nonclassical effects have also been reported in these intermediate states. But till now higher order antibunching is predicted in only one type of intermediate state, which is known as shadowed negative binomial state. Recently we have shown that the higher order antibunching is not a rare phenomenon [P. Gupta, P. Pandey, A. Pathak, J. Phys. B 39 (2006) 1137]. To establish our earlier claim further, here we have shown that the higher order antibunching can be seen in different intermediate states, such as binomial state, reciprocal binomial state, hypergeometric state, generalized binomial state, negative binomial state and photon added coherent state. We have studied the possibility of observing the higher order subpoissonian photon statistics in different limits of intermediate states. The effects of different control parameters on the depth of non classicality have also been studied in this connection and it has been shown that the depth of nonclassicality can be tuned by controlling various physical parameters

Thermal flexural analysis of cross-ply laminated plates using trigonometric shear deformation theory

Directory of Open Access Journals (Sweden)

Yuwaraj Marotrao Ghugal

Full Text Available Thermal stresses and displacements for orthotropic, two-layer antisymmetric, and three-layer symmetric square cross-ply laminated plates subjected to nonlinear thermal load through the thickness of laminated plates are presented by using trigonometric shear deformation theory. The in-plane displacement field uses sinusoidal function in terms of thickness co-ordinate to include the shear deformation effect. The theory satisfies the shear stress free boundary conditions on the top and bottom surfaces of the plate. The present theory obviates the need of shear correction factor. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. The validity of present theory is verified by comparing the results with those of classical plate theory and first order shear deformation theory and higher order shear deformation theory.

''Over the horizon'' SANS: Measurements on near-surface Poiseuille shear-induced ordering of dilute solutions of threadlike micelles

International Nuclear Information System (INIS)

Hamilton, W.A.; Butler, P.D.; Hayter, J.B.; Magid, L.J.; Kreke, P.J.

1995-01-01

Although the behavior of a fluid under shear near a surface can be expected to be critically important to its drag and lubrication properties, most shear measurements to date have been of the bulk. This paper outlines the use of a specially developed Poiseuille shear cell at grazing incidence to measure the small-angle neutron scattering (SANS) signal from the first few tens of microns in the interfacial region. The authors illustrate the technique with measurements made on the near-surface ordering in flow past a quartz surface of dilute surfactant solutions comprising highly extended self-assembling ''threadlike'' micelles

A Higher-Order Colon Translation

DEFF Research Database (Denmark)

Danvy, Olivier; Nielsen, Lasse Reichstein

2001-01-01

A lambda-encoding such as the CPS transformation gives rise to administrative redexes. In his seminal article ``Call-by-name, call-by-value and the lambda-calculus'', 25 years ago, Plotkin tackled administrative reductions using a so-called ``colon translation.'' 10 years ago, Danvy and Filinski...... integrated administrative reductions in the CPS transformation, making it operate in one pass. The technique applies to other lambda-encodings (e.g., variants of CPS), but we do not see it used in practice--instead, Plotkin's colon translation appears to be favored. Therefore, in an attempt to link both...... techniques, we recast Plotkin's proof of Indifference and Simulation to the higher-order specification of the one-pass CPS transformation. To this end, we extend his colon translation from first order to higher order...

A Paraconsistent Higher Order Logic

DEFF Research Database (Denmark)

Villadsen, Jørgen

2004-01-01

of paraconsistent logics in knowledge-based systems, logical semantics of natural language, etc. Higher order logics have the advantages of being expressive and with several automated theorem provers available. Also the type system can be helpful. We present a concise description of a paraconsistent higher order...... of the logic is examined by a case study in the domain of medicine. Thus we try to build a bridge between the HOL and MVL communities. A sequent calculus is proposed based on recent work by Muskens. Many non-classical logics are, at the propositional level, funny toys which work quite good, but when one wants...

Higher-order force gradient symplectic algorithms

Science.gov (United States)

Chin, Siu A.; Kidwell, Donald W.

2000-12-01

We show that a recently discovered fourth order symplectic algorithm, which requires one evaluation of force gradient in addition to three evaluations of the force, when iterated to higher order, yielded algorithms that are far superior to similarly iterated higher order algorithms based on the standard Forest-Ruth algorithm. We gauge the accuracy of each algorithm by comparing the step-size independent error functions associated with energy conservation and the rotation of the Laplace-Runge-Lenz vector when solving a highly eccentric Kepler problem. For orders 6, 8, 10, and 12, the new algorithms are approximately a factor of 103, 104, 104, and 105 better.

An analytical study of the effects of transverse shear deformation and anisotropy on natural vibration frequencies of laminated cylinders

Science.gov (United States)

Jegley, Dawn C.

1988-01-01

Natural vibration frequencies of orthotropic and anisotropic simply supported right circular cylinders are predicted using a higher-order transverse-shear deformation theory. A comparison of natural vibration frequencies predicted by first-order transverse-shear deformation theory and the higher-order theory shows that an additional allowance for transverse shear deformation has a negligible effect on the lowest predicted natural vibration frequencies of laminated cylinders but significantly reduces the higher natural vibration frequencies. A parametric study of the effects of ply orientation on the natural vibration frequencies of laminated cylinders indicates that while stacking sequence affects natural vibration frequencies, cylinder geometry is more important in predicting transverse-shear deformation effects. Interaction curves for cylinders subjected to axial compressive loadings and low natural vibration frequencies indicate that transverse shearing effects are less important in predicting low natural vibration frequencies than in predicting axial compressive buckling loads. The effects of anisotropy are more important than the effects of transverse shear deformation for most strongly anisotropic laminated cylinders in predicting natural vibration frequencies. However, transverse-shear deformation effects are important in predicting high natural vibration frequencies of thick-walled laminated cylinders. Neglecting either anisotropic effects or transverse-shear deformation effects leads to non-conservative errors in predicted natural vibration frequencies.

An analytical study of the effects of transverse shear deformation and anisotropy on natural vibation frequencies of laminated cylinders

Science.gov (United States)

Jegley, Dawn C.

1989-01-01

Natural vibration frequencies of orthotropic and anisotropic simply supported right circular cylinders are predicted using a higher-order transverse-shear deformation theory. A comparison of natural vibration frequencies predicted by first-order transverse-shear deformation theory and the higher-order theory shows that an additional allowance for transverse shear deformation has a negligible effect on the lowest predicted natural vibration frequencies of laminated cylinders but significantly reduces the higher natural vibration frequencies. A parametric study of the effects of ply orientation on the natural vibration frequencies of laminated cylinders indicates that while stacking sequence affects natural vibration frequencies, cylinder geometry is more important in predicting transverse-shear deformation effects. Interaction curves for cylinders subjected to axial compressive loadings and low natural vibration frequencies indicate that transverse shearing effects are less important in predicting low natural vibration frequencies than in predicting axial compressive buckling loads. The effects of anisotropy are more important than the effects of transverse shear deformation for most strongly anisotropic laminated cylinders in predicting natural vibration frequencies. However, transverse-shear deformation effects are important in predicting high natural vibration frequencies of thick-walled laminated cylinders. Neglecting either anisotropic effects or transverse-shear deformation effects leads to non-conservative errors in predicted natural vibration frequencies.

Skinner-Rusk unified formalism for higher-order systems

Science.gov (United States)

Prieto-Martínez, Pedro Daniel; Román-Roy, Narciso

2012-07-01

The Lagrangian-Hamiltonian unified formalism of R. Skinner and R. Rusk was originally stated for autonomous dynamical systems in classical mechanics. It has been generalized for non-autonomous first-order mechanical systems, first-order and higher-order field theories, and higher-order autonomous systems. In this work we present a generalization of this formalism for higher-order non-autonomous mechanical systems.

Shear strength of non-shear reinforced concrete elements

DEFF Research Database (Denmark)

Hoang, Cao linh

1997-01-01

The paper deals with the shear strength of prestressed hollow-core slabs determined by the theory of plasticity. Two failure mechanisms are considered in order to derive the solutions.In the case of sliding failure in a diagonal crack, the shear strength is determined by means of the crack sliding...

Higher-order curvature terms and extended inflation

International Nuclear Information System (INIS)

Wang Yun

1990-01-01

We consider higher-order curvature terms in context of the Brans-Dicke theory of gravity, and investigate the effects of these terms on extended inflationary theories. We find that the higher-order curvature terms tend to speed up inflation, although the original extended-inflation solutions are stable when these terms are small. Analytical solutions are found for two extreme cases: when the higher-order curvature terms are small, and when they dominate. A conformal transformation is employed in solving the latter case, and some of the subtleties in this technique are discussed. We note that percolation is less likely to occur when the higher-order curvature terms are present. An upper bound on α is expected if we are to avoid excessive and inadequate percolation of true-vacuum bubbles

CFHTLenS: a Gaussian likelihood is a sufficient approximation for a cosmological analysis of third-order cosmic shear statistics

Science.gov (United States)

Simon, P.; Semboloni, E.; van Waerbeke, L.; Hoekstra, H.; Erben, T.; Fu, L.; Harnois-Déraps, J.; Heymans, C.; Hildebrandt, H.; Kilbinger, M.; Kitching, T. D.; Miller, L.; Schrabback, T.

2015-05-01

We study the correlations of the shear signal between triplets of sources in the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) to probe cosmological parameters via the matter bispectrum. In contrast to previous studies, we adopt a non-Gaussian model of the data likelihood which is supported by our simulations of the survey. We find that for state-of-the-art surveys, similar to CFHTLenS, a Gaussian likelihood analysis is a reasonable approximation, albeit small differences in the parameter constraints are already visible. For future surveys we expect that a Gaussian model becomes inaccurate. Our algorithm for a refined non-Gaussian analysis and data compression is then of great utility especially because it is not much more elaborate if simulated data are available. Applying this algorithm to the third-order correlations of shear alone in a blind analysis, we find a good agreement with the standard cosmological model: Σ _8=σ _8(Ω _m/0.27)^{0.64}=0.79^{+0.08}_{-0.11} for a flat Λ cold dark matter cosmology with h = 0.7 ± 0.04 (68 per cent credible interval). Nevertheless our models provide only moderately good fits as indicated by χ2/dof = 2.9, including a 20 per cent rms uncertainty in the predicted signal amplitude. The models cannot explain a signal drop on scales around 15 arcmin, which may be caused by systematics. It is unclear whether the discrepancy can be fully explained by residual point spread function systematics of which we find evidence at least on scales of a few arcmin. Therefore we need a better understanding of higher order correlations of cosmic shear and their systematics to confidently apply them as cosmological probes.

Higher order mode optical fiber Raman amplifiers

DEFF Research Database (Denmark)

Rottwitt, Karsten; Friis, Søren Michael Mørk; Usuga Castaneda, Mario A.

2016-01-01

We review higher order mode Raman amplifiers and discuss recent theoretical as well as experimental results including system demonstrations.......We review higher order mode Raman amplifiers and discuss recent theoretical as well as experimental results including system demonstrations....

Nonlocal higher order evolution equations

KAUST Repository

Rossi, Julio D.

2010-06-01

In this article, we study the asymptotic behaviour of solutions to the nonlocal operator ut(x, t)1/4(-1)n-1 (J*Id -1)n (u(x, t)), x ∈ ℝN, which is the nonlocal analogous to the higher order local evolution equation vt(-1)n-1(Δ)nv. We prove that the solutions of the nonlocal problem converge to the solution of the higher order problem with the right-hand side given by powers of the Laplacian when the kernel J is rescaled in an appropriate way. Moreover, we prove that solutions to both equations have the same asymptotic decay rate as t goes to infinity. © 2010 Taylor & Francis.

Conceptualizing and Assessing Higher-Order Thinking in Reading

Science.gov (United States)

Afflerbach, Peter; Cho, Byeong-Young; Kim, Jong-Yun

2015-01-01

Students engage in higher-order thinking as they read complex texts and perform complex reading-related tasks. However, the most consequential assessments, high-stakes tests, are currently limited in providing information about students' higher-order thinking. In this article, we describe higher-order thinking in relation to reading. We provide a…

Application of Mass Lumped Higher Order Finite Elements

International Nuclear Information System (INIS)

J. Chen, H.R. Strauss, S.C. Jardin, W. Park, L.E. Sugiyama, G. Fu, J. Breslau

2005-01-01

There are many interesting phenomena in extended-MHD such as anisotropic transport, mhd, 2-fluid effects stellarator and hot particles. Any one of them challenges numerical analysts, and researchers are seeking for higher order methods, such as higher order finite difference, higher order finite elements and hp/spectral elements. It is true that these methods give more accurate solution than their linear counterparts. However, numerically they are prohibitively expensive. Here we give a successful solution of this conflict by applying mass lumped higher order finite elements. This type of elements not only keep second/third order accuracy but also scale closely to linear elements by doing mass lumping. This is especially true for second order lump elements. Full M3D and anisotropic transport models are studied

Shear instability of a gyroid diblock copolymer

DEFF Research Database (Denmark)

Eskimergen, Rüya; Mortensen, Kell; Vigild, Martin Etchells

2005-01-01

-induced destabilization is discussed in relation to analogous observations on shear-induced order-to-order and disorder-to-order transitions observed in related block copolymer systems and in microemulsions. It is discussed whether these phenomena originate in shear-reduced fluctuations or shear-induced dislocations....

Higher-order techniques in computational electromagnetics

CERN Document Server

Graglia, Roberto D

2016-01-01

Higher-Order Techniques in Computational Electromagnetics explains 'high-order' techniques that can significantly improve the accuracy, computational cost, and reliability of computational techniques for high-frequency electromagnetics, such as antennas, microwave devices and radar scattering applications.

Prediction of stably stratified homogeneous shear flows with second-order turbulence models

International Nuclear Information System (INIS)

Pereira, J C F; Rocha, J M P

2010-01-01

The present study investigated the role of pressure-correlation second-order turbulence modelling schemes on the predicted behaviour of stably stratified homogeneous vertical-sheared turbulence. The pressure-correlation terms were modelled with a nonlinear formulation (Craft 1991), which was compared with a linear pressure-strain model and the 'isotropization of production' model for the pressure-scalar correlation. Two additional modelling issues were investigated: the influence of the buoyancy term in the kinetic energy dissipation rate equation and the time scale in the thermal production term in the scalar variance dissipation equation. The predicted effects of increasing the Richardson number on turbulence characteristics were compared against a comprehensive set of direct numerical simulation databases. The linear models provide a broadly satisfactory description of the major effects of the Richardson number on stratified shear flow. The buoyancy term in the dissipation equation of the turbulent kinetic energy generates excessively low levels of dissipation. For moderate and large Richardson numbers, the term yields unrealistic linear oscillations in the shear and buoyancy production terms, and therefore should be dropped in this flow (or at least their coefficient c ε3 should be substantially reduced from its standard value). The mechanical dissipation time scale provides marginal improvements in comparison to the scalar time scale in the production. The observed inaccuracy of the linear model in predicting the magnitude of the effects on the velocity anisotropy was demonstrated to be attributed mainly to the defective behaviour of the pressure-correlation model, especially for stronger stratification. The turbulence closure embodying a nonlinear formulation for the pressure-correlations and specific versions of the dissipation equations failed to predict the tendency of the flow to anisotropy with increasing stratification. By isolating the effects of the

Higher order Lie-Baecklund symmetries of evolution equations

International Nuclear Information System (INIS)

Roy Chowdhury, A.; Roy Chowdhury, K.; Paul, S.

1983-10-01

We have considered in detail the analysis of higher order Lie-Baecklund symmetries for some representative nonlinear evolution equations. Until now all such symmetry analyses have been restricted only to the first order of the infinitesimal parameter. But the existence of Baecklund transformation (which can be shown to be an overall sum of higher order Lie-Baecklund symmetries) makes it necessary to search for such higher order Lie-Baecklund symmetries directly without taking recourse to the Baecklund transformation or inverse scattering technique. (author)

Analogy, higher order thinking, and education.

Science.gov (United States)

Richland, Lindsey Engle; Simms, Nina

2015-01-01

Analogical reasoning, the ability to understand phenomena as systems of structured relationships that can be aligned, compared, and mapped together, plays a fundamental role in the technology rich, increasingly globalized educational climate of the 21st century. Flexible, conceptual thinking is prioritized in this view of education, and schools are emphasizing 'higher order thinking', rather than memorization of a cannon of key topics. The lack of a cognitively grounded definition for higher order thinking, however, has led to a field of research and practice with little coherence across domains or connection to the large body of cognitive science research on thinking. We review literature on analogy and disciplinary higher order thinking to propose that relational reasoning can be productively considered the cognitive underpinning of higher order thinking. We highlight the utility of this framework for developing insights into practice through a review of mathematics, science, and history educational contexts. In these disciplines, analogy is essential to developing expert-like disciplinary knowledge in which concepts are understood to be systems of relationships that can be connected and flexibly manipulated. At the same time, analogies in education require explicit support to ensure that learners notice the relevance of relational thinking, have adequate processing resources available to mentally hold and manipulate relations, and are able to recognize both the similarities and differences when drawing analogies between systems of relationships. © 2015 John Wiley & Sons, Ltd.

Thermal analysis of smart composite laminated angle-ply using higher order shear deformation theory with zig zag function

Science.gov (United States)

YagnaSri, P.; Siddiqui, Maimuna; Vijaya Nirmala, M.

2018-03-01

The objective of the work is to develop the higher order theory for piezoelectric composite laminated plates with zigzag function and to determine the thermal characteristics of piezoelectric laminated plate with zig zag function for different aspect ratios (a/h), thickness ratios (z/h) and voltage and also to evaluate electric potential function by solving second order differential equation satisfying electric boundary conditions along the thickness direction of piezoelectric layer. The related functions and derivations for equation of motion are obtained using the dynamic version of the principle of virtual work or Hamilton’s principle. The solutions are obtained by using Navier’s stokes method for anti-symmetric angle-ply with specific type of simply supported boundary conditions. Computer programs have been developed for realistic prediction of stresses and deflections for various sides to thickness ratios (a/h) and voltages.

Electromagnetic cloaking in higher order spherical cloaks

Science.gov (United States)

Sidhwa, H. H.; Aiyar, R. P. R. C.; Kulkarni, S. V.

2017-06-01

The inception of transformation optics has led to the realisation of the invisibility devices for various applications, one of which is spherical cloaking. In this paper, a formulation for a higher-order spherical cloak has been proposed to reduce its physical thickness significantly by introducing a nonlinear relation between the original and transformed coordinate systems and it has been verified using the ray tracing approach. Analysis has been carried out to observe the anomalies in the variation of refractive index for higher order cloaks indicating the presence of poles in the relevant equations. Furthermore, a higher-order spherical cloak with predefined values of the material characteristics on its inner and outer surfaces has been designed for practical application.

Higher-order Jordan Osserman pseudo-Riemannian manifolds

International Nuclear Information System (INIS)

Gilkey, Peter B; Ivanova, Raina; Zhang Tan

2002-01-01

We study the higher-order Jacobi operator in pseudo-Riemannian geometry. We exhibit a family of manifolds so that this operator has constant Jordan normal form on the Grassmannian of subspaces of signature (r, s) for certain values of (r, s). These pseudo-Riemannian manifolds are new and non-trivial examples of higher-order Osserman manifolds

Higher-order Jordan Osserman pseudo-Riemannian manifolds

Energy Technology Data Exchange (ETDEWEB)

Gilkey, Peter B [Mathematics Department, University of Oregon, Eugene, OR 97403 (United States); Ivanova, Raina [Mathematics Department, University of Hawaii - Hilo, 200 W Kawili St, Hilo, HI 96720 (United States); Zhang Tan [Department of Mathematics and Statistics, Murray State University, Murray, KY 42071 (United States)

2002-09-07

We study the higher-order Jacobi operator in pseudo-Riemannian geometry. We exhibit a family of manifolds so that this operator has constant Jordan normal form on the Grassmannian of subspaces of signature (r, s) for certain values of (r, s). These pseudo-Riemannian manifolds are new and non-trivial examples of higher-order Osserman manifolds.

Research Concerning the Shearing Strength of Black Locust Wood

Directory of Open Access Journals (Sweden)

Mihaela POROJAN

2011-06-01

Full Text Available The paper presents the experimental resultsobtained for the shearing strength of black locustwood (Robinia pseudacacia L. harvested from twogeographical areas (North and South of Romania.Wood is subjected to shearing stress when usedwithin different fields, and especially inconstructions. Tangential stresses are produced inthe shearing sections and they are influenced by thestructure of wood through the position of theshearing plane and of the force direction towards thegrain. Accordingly, several shearing types arepossible. The shearing strengths for the three mainshearing types, both on radial and tangentialdirection were determined within the present study.The evaluation of data was achieved by using theANOVA analysis, in order to test the level ofsignificance depending on the shearing planeorientation and the harvesting area. The obtainedresults were compared to the values mentionedwithin reference literature for this wood species andtwo other hardwood species with similar density. It isworth to be mentioned that the shearing strengths ofblack locust wood from Romania (both from Northand South are generally higher than those indicatedby reference literature for oak and beech. Thisrecommends black locust wood as constructionwood and for other applications where wood issubjected to shearing stress.

Difference equations in massive higher order calculations

International Nuclear Information System (INIS)

Bierenbaum, I.; Bluemlein, J.; Klein, S.; Schneider, C.

2007-07-01

The calculation of massive 2-loop operator matrix elements, required for the higher order Wilson coefficients for heavy flavor production in deeply inelastic scattering, leads to new types of multiple infinite sums over harmonic sums and related functions, which depend on the Mellin parameter N. We report on the solution of these sums through higher order difference equations using the summation package Sigma. (orig.)

Higher-order harmonics of general limited diffraction Bessel beams

International Nuclear Information System (INIS)

Ding De-Sheng; Huang Jin-Huang

2016-01-01

In this paper, we extensively study the higher-order harmonic generation of the general limited diffraction m -th-order Bessel beam. The analysis is based on successive approximations of the Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation. Asymptotic expansions are presented for higher-order harmonic Bessel beams in near and far fields. The validity of asymptotic approximation is also analyzed. The higher-order harmonic of the Bessel beam with the lowest zero-order is taken as a special example. (special topic)

Higher-order harmonics of general limited diffraction Bessel beams

Science.gov (United States)

Ding, De-Sheng; Huang, Jin-Huang

2016-12-01

In this paper, we extensively study the higher-order harmonic generation of the general limited diffraction m-th-order Bessel beam. The analysis is based on successive approximations of the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. Asymptotic expansions are presented for higher-order harmonic Bessel beams in near and far fields. The validity of asymptotic approximation is also analyzed. The higher-order harmonic of the Bessel beam with the lowest zero-order is taken as a special example. Project supported by the National Natural Science Foundation of China (Grant Nos. 11074038 and 11374051).

Higher order QCD corrections in small x physics

International Nuclear Information System (INIS)

Chachamis, G.

2006-11-01

We study higher order QCD corrections in small x Physics. The numerical implementation of the full NLO photon impact factor is the remaining necessary piece for the testing of the NLO BFKL resummation against data from physical processes, such as γ * γ * collisions. We perform the numerical integration over phase space for the virtual corrections to the NLO photon impact factor. This, along with the previously calculated real corrections, makes feasible in the near future first estimates for the γ*γ* total cross section, since the convolution of the full impact factor with the NLO BFKL gluon Green's function is now straightforward. The NLO corrections for the photon impact factor are sizeable and negative. In the second part of this thesis, we estimate higher order correction to the BK equation. We are mainly interested in whether partonic saturation delays or not in rapidity when going beyond the leading order. In our investigation, we use the so called 'rapidity veto' which forbid two emissions to be very close in rapidity, to 'switch on' higher order corrections to the BK equation. From analytic and numerical analysis, we conclude that indeed saturation does delay in rapidity when higher order corrections are taken into account. In the last part, we investigate higher order QCD corrections as additional corrections to the Electroweak (EW) sector. The question of whether BFKL corrections are of any importance in the Regge limit for the EW sector seems natural; although they arise in higher loop level, the accumulation of logarithms in energy s at high energies, cannot be dismissed without an investigation. We focus on the process γγ→ZZ. We calculate the pQCD corrections in the forward region at leading logarithmic (LL) BFKL accuracy, which are of the order of few percent at the TeV energy scale. (orig.)

Higher order QCD corrections in small x physics

Energy Technology Data Exchange (ETDEWEB)

Chachamis, G.

2006-11-15

We study higher order QCD corrections in small x Physics. The numerical implementation of the full NLO photon impact factor is the remaining necessary piece for the testing of the NLO BFKL resummation against data from physical processes, such as {gamma}{sup *}{gamma}{sup *} collisions. We perform the numerical integration over phase space for the virtual corrections to the NLO photon impact factor. This, along with the previously calculated real corrections, makes feasible in the near future first estimates for the {gamma}*{gamma}* total cross section, since the convolution of the full impact factor with the NLO BFKL gluon Green's function is now straightforward. The NLO corrections for the photon impact factor are sizeable and negative. In the second part of this thesis, we estimate higher order correction to the BK equation. We are mainly interested in whether partonic saturation delays or not in rapidity when going beyond the leading order. In our investigation, we use the so called 'rapidity veto' which forbid two emissions to be very close in rapidity, to 'switch on' higher order corrections to the BK equation. From analytic and numerical analysis, we conclude that indeed saturation does delay in rapidity when higher order corrections are taken into account. In the last part, we investigate higher order QCD corrections as additional corrections to the Electroweak (EW) sector. The question of whether BFKL corrections are of any importance in the Regge limit for the EW sector seems natural; although they arise in higher loop level, the accumulation of logarithms in energy s at high energies, cannot be dismissed without an investigation. We focus on the process {gamma}{gamma}{yields}ZZ. We calculate the pQCD corrections in the forward region at leading logarithmic (LL) BFKL accuracy, which are of the order of few percent at the TeV energy scale. (orig.)

Nonlocal higher order evolution equations

KAUST Repository

Rossi, Julio D.; Schö nlieb, Carola-Bibiane

2010-01-01

In this article, we study the asymptotic behaviour of solutions to the nonlocal operator ut(x, t)1/4(-1)n-1 (J*Id -1)n (u(x, t)), x ∈ ℝN, which is the nonlocal analogous to the higher order local evolution equation vt(-1)n-1(Δ)nv. We prove

Unambiguous formalism for higher order Lagrangian field theories

International Nuclear Information System (INIS)

Campos, Cedric M; De Leon, Manuel; De Diego, David MartIn; Vankerschaver, Joris

2009-01-01

The aim of this paper is to propose an unambiguous intrinsic formalism for higher order field theories which avoids the arbitrariness in the generalization of the conventional description of field theories, and implies the existence of different Cartan forms and Legendre transformations. We propose a differential-geometric setting for the dynamics of a higher order field theory, based on the Skinner and Rusk formalism for mechanics. This approach incorporates aspects of both the Lagrangian and the Hamiltonian description, since the field equations are formulated using the Lagrangian on a higher order jet bundle and the canonical multisymplectic form on its affine dual. As both of these objects are uniquely defined, the Skinner-Rusk approach has the advantage that it does not suffer from the arbitrariness in conventional descriptions. The result is that we obtain a unique and global intrinsic version of the Euler-Lagrange equations for higher order field theories. Several examples illustrate our construction.

Time-Discrete Higher-Order ALE Formulations: Stability

KAUST Repository

Bonito, Andrea; Kyza, Irene; Nochetto, Ricardo H.

2013-01-01

on the stability of the PDE but may influence that of a discrete scheme. We examine this critical issue for higher-order time stepping without space discretization. We propose time-discrete discontinuous Galerkin (dG) numerical schemes of any order for a time

The Meaning of Higher-Order Factors in Reflective-Measurement Models

Science.gov (United States)

Eid, Michael; Koch, Tobias

2014-01-01

Higher-order factor analysis is a widely used approach for analyzing the structure of a multidimensional test. Whenever first-order factors are correlated researchers are tempted to apply a higher-order factor model. But is this reasonable? What do the higher-order factors measure? What is their meaning? Willoughby, Holochwost, Blanton, and Blair…

Nil Bohr-sets and almost automorphy of higher order

CERN Document Server

Huang, Wen; Ye, Xiangdong

2016-01-01

Two closely related topics, higher order Bohr sets and higher order almost automorphy, are investigated in this paper. Both of them are related to nilsystems. In the first part, the problem which can be viewed as the higher order version of an old question concerning Bohr sets is studied: for any d\\in \\mathbb{N} does the collection of \\{n\\in \\mathbb{Z}: S\\cap (S-n)\\cap\\ldots\\cap (S-dn)\

Higher order cumulants in colorless partonic plasma

Energy Technology Data Exchange (ETDEWEB)

Cherif, S. [Sciences and Technologies Department, University of Ghardaia, Ghardaia, Algiers (Algeria); Laboratoire de Physique et de Mathématiques Appliquées (LPMA), ENS-Kouba (Bachir El-Ibrahimi), Algiers (Algeria); Ahmed, M. A. A. [Department of Physics, College of Science, Taibah University Al-Madinah Al-Mounawwarah KSA (Saudi Arabia); Department of Physics, Taiz University in Turba, Taiz (Yemen); Laboratoire de Physique et de Mathématiques Appliquées (LPMA), ENS-Kouba (Bachir El-Ibrahimi), Algiers (Algeria); Ladrem, M., E-mail: mladrem@yahoo.fr [Department of Physics, College of Science, Taibah University Al-Madinah Al-Mounawwarah KSA (Saudi Arabia); Laboratoire de Physique et de Mathématiques Appliquées (LPMA), ENS-Kouba (Bachir El-Ibrahimi), Algiers (Algeria)

2016-06-10

Any physical system considered to study the QCD deconfinement phase transition certainly has a finite volume, so the finite size effects are inevitably present. This renders the location of the phase transition and the determination of its order as an extremely difficult task, even in the simplest known cases. In order to identify and locate the colorless QCD deconfinement transition point in finite volume T{sub 0}(V), a new approach based on the finite-size cumulant expansion of the order parameter and the ℒ{sub m,n}-Method is used. We have shown that both cumulants of higher order and their ratios, associated to the thermodynamical fluctuations of the order parameter, in QCD deconfinement phase transition behave in a particular enough way revealing pronounced oscillations in the transition region. The sign structure and the oscillatory behavior of these in the vicinity of the deconfinement phase transition point might be a sensitive probe and may allow one to elucidate their relation to the QCD phase transition point. In the context of our model, we have shown that the finite volume transition point is always associated to the appearance of a particular point in whole higher order cumulants under consideration.

On the expressiveness and decidability of higher-order process calculi

NARCIS (Netherlands)

Lanese, Ivan; Perez, Jorge A.; Sangiorgi, Davide; Schmitt, Alan

In higher-order process calculi, the values exchanged in communications may contain processes. A core calculus of higher-order concurrency is studied; it has only the operators necessary to express higher-order communications: input prefix, process output, and parallel composition. By exhibiting a

Multilevel Fast Multipole Method for Higher Order Discretizations

DEFF Research Database (Denmark)

Borries, Oscar Peter; Meincke, Peter; Jorgensen, Erik

2014-01-01

The multi-level fast multipole method (MLFMM) for a higher order (HO) discretization is demonstrated on high-frequency (HF) problems, illustrating for the first time how an efficient MLFMM for HO can be achieved even for very large groups. Applying several novel ideas, beneficial to both lower...... order and higher order discretizations, results from a low-memory, high-speed MLFMM implementation of a HO hierarchical discretization are shown. These results challenge the general view that the benefits of HO and HF-MLFMM cannot be combined....

Fluid Effects on Shear Waves in Finely Layered Porous Media

International Nuclear Information System (INIS)

Berryman, J G

2004-01-01

Although there are five effective shear moduli for any layered VTI medium, one and only one effective shear modulus for the layered system contains all the dependence of pore fluids on the elastic or poroelastic constants that can be observed in vertically polarized shear waves. Pore fluids can increase the magnitude the shear energy stored by this modulus by a term that ranges from the smallest to the largest shear moduli of the VTI system. But, since there are five shear moduli in play, the increase in shear energy overall is reduced by a factor of about 5 in general. We can therefore give definite bounds on the maximum increase of shear modulus, being about 20% of the permitted range, when gas is fully replaced by liquid. An attendant increase of density (depending on porosity and fluid density) by approximately 5 to 10% partially offsets the effect of this shear modulus increase. Thus, an increase of shear wave speed on the order of 5 to 10% is shown to be possible when circumstances are favorable - i.e., when the shear modulus fluctuations are large (resulting in strong anisotropy), and the medium behaves in an undrained fashion due to fluid trapping. At frequencies higher than seismic (such as sonic and ultrasonic waves for well-logging or laboratory experiments), short response times also produce the requisite undrained behavior and, therefore, fluids also affect shear waves at high frequencies by increasing rigidity

Higher-order modulation instability in nonlinear fiber optics.

Science.gov (United States)

Erkintalo, Miro; Hammani, Kamal; Kibler, Bertrand; Finot, Christophe; Akhmediev, Nail; Dudley, John M; Genty, Goëry

2011-12-16

We report theoretical, numerical, and experimental studies of higher-order modulation instability in the focusing nonlinear Schrödinger equation. This higher-order instability arises from the nonlinear superposition of elementary instabilities, associated with initial single breather evolution followed by a regime of complex, yet deterministic, pulse splitting. We analytically describe the process using the Darboux transformation and compare with experiments in optical fiber. We show how a suitably low frequency modulation on a continuous wave field induces higher-order modulation instability splitting with the pulse characteristics at different phases of evolution related by a simple scaling relationship. We anticipate that similar processes are likely to be observed in many other systems including plasmas, Bose-Einstein condensates, and deep water waves. © 2011 American Physical Society

Higher-order rewriting and partial evaluation

DEFF Research Database (Denmark)

Danvy, Olivier; Rose, Kristoffer H.

1998-01-01

We demonstrate the usefulness of higher-order rewriting techniques for specializing programs, i.e., for partial evaluation. More precisely, we demonstrate how casting program specializers as combinatory reduction systems (CRSs) makes it possible to formalize the corresponding program...

Higher-Order Separation Logic in Isabelle/HOLCF

DEFF Research Database (Denmark)

Varming, Carsten; Birkedal, Lars

2008-01-01

We formalize higher-order separation logic for a first-order imperative language with procedures and local variables in Isabelle/HOLCF. The assertion language is modeled in such a way that one may use any theory defined in Isabelle/HOLCF to construct assertions, e.g., primitive recursion, least o...

Meta-Logical Reasoning in Higher-Order Logic

DEFF Research Database (Denmark)

Villadsen, Jørgen; Schlichtkrull, Anders; Hess, Andreas Viktor

The semantics of first-order logic (FOL) can be described in the meta-language of higher-order logic (HOL). Using HOL one can prove key properties of FOL such as soundness and completeness. Furthermore, one can prove sentences in FOL valid using the formalized FOL semantics. To aid...

Freezing of a colloidal liquid subject to shear flow

International Nuclear Information System (INIS)

Bagchi, B.; Thirumalai, D.

1988-01-01

A nonequilibrium generalization of the density-functional theory of freezing is proposed to investigate the shear-induced first-order phase transition in colloidal suspensions. It is assumed that the main effect of a steady shear is to break the symmetry of the structure factor of the liquid and that for small shear rate, the phenomenon of a shear-induced order-disorder transition may be viewed as an equilibrium phase transition. The theory predicts that the effective density at which freezing takes place increases with shear rate. The solid (which is assumed to be a bcc lattice) formed upon freezing is distorted and specifically there is less order in one plane compared with the order in the other two perpendicular planes. It is shown that there exists a critical shear rate above which the colloidal liquid does not undergo a transition to an ordered (or partially ordered) state no matter how large the density is. Conversely, above the critical shear rate an initially formed bcc solid always melts into an amorphous or liquidlike state. Several of these predictions are in qualitative agreement with the light-scattering experiments of Ackerson and Clark. The limitations as well as possible extensions of the theory are also discussed

Experimental and numerical investigations of higher mode effects on seismic inelastic response of reinforced concrete shear walls

Science.gov (United States)

Ghorbanirenani, Iman

This thesis presents two experimental programs together with companion numerical studies that were carried out on reinforced concrete shear walls: static tests and dynamic (shake table) tests. The first series of experiments were monotonic and cyclic quasi-static testing on ductile reinforced concrete shear wall specimens designed and detailed according to the seismic provisions of NBCC 2005 and CSA-A23.3-04 standard. The tests were carried out on full-scale and 1:2.37 reduced scale wall specimens to evaluate the seismic design provisions and similitude law and determine the appropriate scaling factor that could be applied for further studies such as dynamic tests. The second series of experiments were shake table tests conducted on two identical 1:2.33 scaled, 8-storey moderately ductile reinforced concrete shear wall specimens to investigate the effects of higher modes on the inelastic response of slender walls under high frequency ground motions expected in Eastern North America. The walls were designed and detailed according to the seismic provisions of NBCC 2005 and CSA-A23.3-04 standard. The objectives were to validate and understand the inelastic response and interaction of shear, flexure and axial loads in plastic hinge zones of the walls considering the higher mode effects and to investigate the formation of second hinge in upper part of the wall due to higher mode responses. Second mode response significantly affected the response of the walls. This caused inelastic flexural response to develop at the 6th level with approximately the same rotation ductility compared to that observed at the base. Dynamic amplification of the base shear forces was also observed in both walls. Numerical modeling of these two shake table tests was performed to evaluate the test results and validate current modeling approaches. Nonlinear time history analyses were carried out by the reinforced concrete fibre element (OpenSees program) and finite element (VecTor2 program

Shear Elasticity and Shear Viscosity Imaging in Soft Tissue

Science.gov (United States)

Yang, Yiqun

In this thesis, a new approach is introduced that provides estimates of shear elasticity and shear viscosity using time-domain measurements of shear waves in viscoelastic media. Simulations of shear wave particle displacements induced by an acoustic radiation force are accelerated significantly by a GPU. The acoustic radiation force is first calculated using the fast near field method (FNM) and the angular spectrum approach (ASA). The shear waves induced by the acoustic radiation force are then simulated in elastic and viscoelastic media using Green's functions. A parallel algorithm is developed to perform these calculations on a GPU, where the shear wave particle displacements at different observation points are calculated in parallel. The resulting speed increase enables rapid evaluation of shear waves at discrete points, in 2D planes, and for push beams with different spatial samplings and for different values of the f-number (f/#). The results of these simulations show that push beams with smaller f/# require a higher spatial sampling rate. The significant amount of acceleration achieved by this approach suggests that shear wave simulations with the Green's function approach are ideally suited for high-performance GPUs. Shear wave elasticity imaging determines the mechanical parameters of soft tissue by analyzing measured shear waves induced by an acoustic radiation force. To estimate the shear elasticity value, the widely used time-of-flight method calculates the correlation between shear wave particle velocities at adjacent lateral observation points. Although this method provides accurate estimates of the shear elasticity in purely elastic media, our experience suggests that the time-of-flight (TOF) method consistently overestimates the shear elasticity values in viscoelastic media because the combined effects of diffraction, attenuation, and dispersion are not considered. To address this problem, we have developed an approach that directly accounts for all

Experimental study of shear rate dependence in perpetually sheared granular matter

Science.gov (United States)

Liu, Sophie Yang; Guillard, François; Marks, Benjy; Rognon, Pierre; Einav, Itai

2017-06-01

We study the shear behaviour of various granular materials by conducting novel perpetual simple shear experiments over four orders of magnitude of relatively low shear rates. The newly developed experimental apparatus employed is called "3D Stadium Shear Device" which is an extended version of the 2D Stadium Shear Device [1]. This device is able to provide a non-radial dependent perpetual shear flow and a nearly linear velocity profile between two oppositely moving shear walls. Using this device, we are able to test a large variety of granular materials. Here, we demonstrate the applicability of the device on glass beads (diameter 1 mm, 3 mm, and 14 mm) and rice. We particularly focus on studying these materials at very low inertial number I ranging from 10-6 to 10-2. We find that, within this range of I, the friction coefficient μ of glass beads has no shear rate dependence. A particularly appealing observation comes from testing rice, where the attainment of critical state develops under much longer duration than in other materials. Initially during shear we find a value of μ similar to that found for glass beads, but with time this value decreases gradually towards the asymptotic critical state value. The reason, we believe, lies in the fact that rice grains are strongly elongated; hence the time to achieve the stable μ is primarily controlled by the time for particles to align themselves with respect to the shear walls. Furthermore, the initial packing conditions of samples also plays a role in the evolution of μ when the shear strain is small, but that impact will eventually be erased after sufficient shear strain.

Higher-Order and Symbolic Computation

DEFF Research Database (Denmark)

Danvy, Olivier; Mason, Ian

2008-01-01

a series of implementaions that properly account for multiple invocations of the derivative-taking opeatro. In "Adapting Functional Programs to Higher-Order Logic," Scott Owens and Konrad Slind present a variety of examples of terminiation proofs of functional programs written in HOL proof systems. Since......-calculus programs, historically. The anaylsis determines the possible locations of ambients and mirrors the temporla sequencing of actions in the structure of types....

All-fiber Raman Probe using Higher Order Modes

DEFF Research Database (Denmark)

Larsen, Stine Højer Møller; Rishøj, Lars Søgaard; Rottwitt, Karsten

2013-01-01

We demonstrate the first all-fiber Raman probe utilizing higher order modes for the excitation. The spectrum of cyclohexane is measured using both the fundamental mode as well as in-fiber-generated Bessel-like modes.......We demonstrate the first all-fiber Raman probe utilizing higher order modes for the excitation. The spectrum of cyclohexane is measured using both the fundamental mode as well as in-fiber-generated Bessel-like modes....

Asymptotic Expansions for Higher-Order Scalar Difference Equations

Directory of Open Access Journals (Sweden)

Pituk Mihály

2007-01-01

Full Text Available We give an asymptotic expansion of the solutions of higher-order Poincaré difference equation in terms of the characteristic solutions of the limiting equation. As a consequence, we obtain an asymptotic description of the solutions approaching a hyperbolic equilibrium of a higher-order nonlinear difference equation with sufficiently smooth nonlinearity. The proof is based on the inversion formula for the z -transform and the residue theorem.

On the origin of higher braces and higher-order derivations

Czech Academy of Sciences Publication Activity Database

Markl, Martin

2015-01-01

Roč. 10, č. 3 (2015), s. 637-667 ISSN 2193-8407 Institutional support: RVO:67985840 Keywords : Koszul braces * Börjeseon braces * higher-order derivation Subject RIV: BA - General Mathematics Impact factor: 0.600, year: 2015 http://link.springer.com/article/10.1007/s40062-014-0079-2

Higher order correlations in computed particle distributions

International Nuclear Information System (INIS)

Hanerfeld, H.; Herrmannsfeldt, W.; Miller, R.H.

1989-03-01

The rms emittances calculated for beam distributions using computer simulations are frequently dominated by higher order aberrations. Thus there are substantial open areas in the phase space plots. It has long been observed that the rms emittance is not an invariant to beam manipulations. The usual emittance calculation removes the correlation between transverse displacement and transverse momentum. In this paper, we explore the possibility of defining higher order correlations that can be removed from the distribution to result in a lower limit to the realizable emittance. The intent is that by inserting the correct combinations of linear lenses at the proper position, the beam may recombine in a way that cancels the effects of some higher order forces. An example might be the non-linear transverse space charge forces which cause a beam to spread. If the beam is then refocused so that the same non-linear forces reverse the inward velocities, the resulting phase space distribution may reasonably approximate the original distribution. The approach to finding the location and strength of the proper lens to optimize the transported beam is based on work by Bruce Carlsten of Los Alamos National Laboratory. 11 refs., 4 figs

Perturbative theory of higher-order collision-enhanced wave mixing

International Nuclear Information System (INIS)

Trebino, R.; Rahn, L.A.

1989-01-01

This paper reports on collision-enhanced resonances which represent an interesting class of nonlinear- optical processes. They occur because collisional dephasing can rephase quantum-mechanical amplitudes that ordinarily cancel out exactly, thereby allowing otherwise unobservable wave-mixing resonances to be seen. This is an especially interesting phenomenon because these resonances are coherent effects that are induced by an incoherent process (collisional dephasing). First predicted in the late 1970s and eventually observed in 1981, these novel effects have now been seen in a wide variety of four-wave-mixing experiments, ranging from self-focusing to coherent anti-Stokes Raman spectroscopy. Recently, the authors have extended these observations to higher order, where the authors have shown both experimentally and theoretically the higher-order, collision-enhanced effects exist in nonlinear optics, appearing as subharmonics of two-photon resonances. Indeed, the authors have found that collision-enhanced processes are ideal systems for studying higher-order, nonlinear-optical effects because very high orders can be made to contribute with little or no saturation braodening. Experiments on sodium in a flame using six- and eight-wave-mixing geometries have revealed still higher-order effects (at least as high- order as χ (13) )

Classical higher-order processes

DEFF Research Database (Denmark)

Montesi, Fabrizio

2017-01-01

Classical Processes (CP) is a calculus where the proof theory of classical linear logic types processes à la Π-calculus, building on a Curry-Howard correspondence between session types and linear propositions. We contribute to this research line by extending CP with process mobility, inspired...... by the Higher-Order Π-calculus. The key to our calculus is that sequents are asymmetric: one side types sessions as in CP and the other types process variables, which can be instantiated with process values. The controlled interaction between the two sides ensures that process variables can be used at will......, but always respecting the linear usage of sessions expected by the environment....

Asymptotic Expansions for Higher-Order Scalar Difference Equations

Directory of Open Access Journals (Sweden)

Ravi P. Agarwal

2007-04-01

Full Text Available We give an asymptotic expansion of the solutions of higher-order Poincaré difference equation in terms of the characteristic solutions of the limiting equation. As a consequence, we obtain an asymptotic description of the solutions approaching a hyperbolic equilibrium of a higher-order nonlinear difference equation with sufficiently smooth nonlinearity. The proof is based on the inversion formula for the z -transform and the residue theorem.

Higher-Order Cyclostationarity Detection for Spectrum Sensing

Directory of Open Access Journals (Sweden)

Julien Renard

2010-01-01

Full Text Available Recent years have shown a growing interest in the concept of Cognitive Radios (CRs, able to access portions of the electromagnetic spectrum in an opportunistic operating way. Such systems require efficient detectors able to work in low Signal-to-Noise Ratio (SNR environments, with little or no information about the signals they are trying to detect. Energy detectors are widely used to perform such blind detection tasks, but quickly reach the so-called SNR wall below which detection becomes impossible Tandra (2005. Cyclostationarity detectors are an interesting alternative to energy detectors, as they exploit hidden periodicities present in man-made signals, but absent in noise. Such detectors use quadratic transformations of the signals to extract the hidden sine-waves. While most of the literature focuses on the second-order transformations of the signals, we investigate the potential of higher-order transformations of the signals. Using the theory of Higher-Order Cyclostationarity (HOCS, we derive a fourth-order detector that performs similarly to the second-order ones to detect linearly modulated signals, at SNR around 0 dB, which may be used if the signals of interest do not exhibit second-order cyclostationarity. More generally this paper reviews the relevant aspects of the cyclostationary and HOCS theory, and shows their potential for spectrum sensing.

Higher-order tensors in diffusion imaging

NARCIS (Netherlands)

Schultz, T.; Fuster, A.; Ghosh, A.; Deriche, R.; Florack, L.M.J.; Lim, L.H.; Westin, C.-F.; Vilanova, A.; Burgeth, B.

2014-01-01

Diffusion imaging is a noninvasive tool for probing the microstructure of fibrous nerve and muscle tissue. Higher-order tensors provide a powerful mathematical language to model and analyze the large and complex data that is generated by its modern variants such as High Angular Resolution Diffusion

Theorem Proving In Higher Order Logics

Science.gov (United States)

Carreno, Victor A. (Editor); Munoz, Cesar A.; Tahar, Sofiene

2002-01-01

The TPHOLs International Conference serves as a venue for the presentation of work in theorem proving in higher-order logics and related areas in deduction, formal specification, software and hardware verification, and other applications. Fourteen papers were submitted to Track B (Work in Progress), which are included in this volume. Authors of Track B papers gave short introductory talks that were followed by an open poster session. The FCM 2002 Workshop aimed to bring together researchers working on the formalisation of continuous mathematics in theorem proving systems with those needing such libraries for their applications. Many of the major higher order theorem proving systems now have a formalisation of the real numbers and various levels of real analysis support. This work is of interest in a number of application areas, such as formal methods development for hardware and software application and computer supported mathematics. The FCM 2002 consisted of three papers, presented by their authors at the workshop venue, and one invited talk.

Experimental study of shear rate dependence in perpetually sheared granular matter

Directory of Open Access Journals (Sweden)

Liu Sophie Yang

2017-01-01

Full Text Available We study the shear behaviour of various granular materials by conducting novel perpetual simple shear experiments over four orders of magnitude of relatively low shear rates. The newly developed experimental apparatus employed is called “3D Stadium Shear Device” which is an extended version of the 2D Stadium Shear Device [1]. This device is able to provide a non-radial dependent perpetual shear flow and a nearly linear velocity profile between two oppositely moving shear walls. Using this device, we are able to test a large variety of granular materials. Here, we demonstrate the applicability of the device on glass beads (diameter 1 mm, 3 mm, and 14 mm and rice. We particularly focus on studying these materials at very low inertial number I ranging from 10−6 to 10−2. We find that, within this range of I, the friction coefficient μ of glass beads has no shear rate dependence. A particularly appealing observation comes from testing rice, where the attainment of critical state develops under much longer duration than in other materials. Initially during shear we find a value of μ similar to that found for glass beads, but with time this value decreases gradually towards the asymptotic critical state value. The reason, we believe, lies in the fact that rice grains are strongly elongated; hence the time to achieve the stable μ is primarily controlled by the time for particles to align themselves with respect to the shear walls. Furthermore, the initial packing conditions of samples also plays a role in the evolution of μ when the shear strain is small, but that impact will eventually be erased after sufficient shear strain.

Exact solutions to two higher order nonlinear Schroedinger equations

International Nuclear Information System (INIS)

Xu Liping; Zhang Jinliang

2007-01-01

Using the homogeneous balance principle and F-expansion method, the exact solutions to two higher order nonlinear Schroedinger equations which describe the propagation of femtosecond pulses in nonlinear fibres are obtained with the aid of a set of subsidiary higher order ordinary differential equations (sub-equations for short)

Role of Wall Shear Stress in Cryptosporidium parvum Oocyst Attachment to Environmental Biofilms.

Science.gov (United States)

Luo, Xia; Jedlicka, Sabrina S; Jellison, Kristen L

2017-12-15

This study investigated Cryptosporidium parvum oocyst deposition onto biofilms as a function of shear stress under laminar or turbulent flow. Annular rotating bioreactors were used to grow stabilized stream biofilms at shear stresses ranging from 0.038 to 0.46 Pa. These steady-state biofilms were then used to assess the impact of hydrodynamic conditions on C. parvum oocyst attachment. C. parvum deposition onto biofilms followed a pseudo-second-order model under both laminar (after a lag phase) and turbulent flows. The total number of oocysts attached to the biofilm at steady state decreased as the hydrodynamic wall shear stress increased. The oocyst deposition rate constant increased with shear stress but decreased at high shear, suggesting that increasing wall shear stress results in faster attachment of Cryptosporidium due to higher mass transport until the shear forces exceed a critical limit that prevents oocyst attachment. These data show that oocyst attachment in the short and long term are impacted differently by shear: higher shear (to a certain limit) may be associated with faster initial oocyst attachment, but lower shear is associated with greater numbers of oocysts attached at equilibrium. IMPORTANCE This research provides experimental evidence to demonstrate that shear stress plays a critical role in protozoan-pathogen transport and deposition in environmental waters. The data presented in this work expand scientific understanding of Cryptosporidium attachment and fate, which will further influence the development of timely and accurate sampling strategies, as well as advanced water treatment technologies, to target protozoan pathogens in surface waters that serve as municipal drinking water sources. Copyright © 2017 American Society for Microbiology.

Self-similarity of higher-order moving averages

Science.gov (United States)

Arianos, Sergio; Carbone, Anna; Türk, Christian

2011-10-01

In this work, higher-order moving average polynomials are defined by straightforward generalization of the standard moving average. The self-similarity of the polynomials is analyzed for fractional Brownian series and quantified in terms of the Hurst exponent H by using the detrending moving average method. We prove that the exponent H of the fractional Brownian series and of the detrending moving average variance asymptotically agree for the first-order polynomial. Such asymptotic values are compared with the results obtained by the simulations. The higher-order polynomials correspond to trend estimates at shorter time scales as the degree of the polynomial increases. Importantly, the increase of polynomial degree does not require to change the moving average window. Thus trends at different time scales can be obtained on data sets with the same size. These polynomials could be interesting for those applications relying on trend estimates over different time horizons (financial markets) or on filtering at different frequencies (image analysis).

Compiler-Directed Transformation for Higher-Order Stencils

Energy Technology Data Exchange (ETDEWEB)

Basu, Protonu [Univ. of Utah, Salt Lake City, UT (United States); Hall, Mary [Univ. of Utah, Salt Lake City, UT (United States); Williams, Samuel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Straalen, Brian Van [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Oliker, Leonid [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Colella, Phillip [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-07-20

As the cost of data movement increasingly dominates performance, developers of finite-volume and finite-difference solutions for partial differential equations (PDEs) are exploring novel higher-order stencils that increase numerical accuracy and computational intensity. This paper describes a new compiler reordering transformation applied to stencil operators that performs partial sums in buffers, and reuses the partial sums in computing multiple results. This optimization has multiple effect son improving stencil performance that are particularly important to higher-order stencils: exploits data reuse, reduces floating-point operations, and exposes efficient SIMD parallelism to backend compilers. We study the benefit of this optimization in the context of Geometric Multigrid (GMG), a widely used method to solvePDEs, using four different Jacobi smoothers built from 7-, 13-, 27-and 125-point stencils. We quantify performance, speedup, andnumerical accuracy, and use the Roofline model to qualify our results. Ultimately, we obtain over 4× speedup on the smoothers themselves and up to a 3× speedup on the multigrid solver. Finally, we demonstrate that high-order multigrid solvers have the potential of reducing total data movement and energy by several orders of magnitude.

Higher-Order Components for Grid Programming

CERN Document Server

Dünnweber, Jan

2009-01-01

Higher-Order Components were developed within the CoreGRID European Network of Excellence and have become an optional extension of the popular Globus middleware. This book provides the reader with hands-on experience, describing a collection of example applications from various fields of science and engineering, including biology and physics.

Higher order aberrations of the eye: Part one

Directory of Open Access Journals (Sweden)

Marsha Oberholzer

2016-06-01

Full Text Available This article is the first in a series of two articles that provide a comprehensive literature review of higher order aberrations (HOAs of the eye. The present article mainly explains the general principles of such HOAs as well as HOAs of importance, and the measuring apparatus used to measure HOAs of the eye. The second article in the series discusses factors contributing to variable results in measurements of HOAs of the eye. Keywords: Higher order aberrations; wavefront aberrations; aberrometer

Lagrangian-Hamiltonian unified formalism for autonomous higher order dynamical systems

International Nuclear Information System (INIS)

Prieto-Martinez, Pedro Daniel; Roman-Roy, Narciso

2011-01-01

The Lagrangian-Hamiltonian unified formalism of Skinner and Rusk was originally stated for autonomous dynamical systems in classical mechanics. It has been generalized for non-autonomous first-order mechanical systems, as well as for first-order and higher order field theories. However, a complete generalization to higher order mechanical systems is yet to be described. In this work, after reviewing the natural geometrical setting and the Lagrangian and Hamiltonian formalisms for higher order autonomous mechanical systems, we develop a complete generalization of the Lagrangian-Hamiltonian unified formalism for these kinds of systems, and we use it to analyze some physical models from this new point of view. (paper)

Higher Order Lagrange Finite Elements In M3D

International Nuclear Information System (INIS)

Chen, J.; Strauss, H.R.; Jardin, S.C.; Park, W.; Sugiyama, L.E.; Fu, G.; Breslau, J.

2004-01-01

The M3D code has been using linear finite elements to represent multilevel MHD on 2-D poloidal planes. Triangular higher order elements, up to third order, are constructed here in order to provide M3D the capability to solve highly anisotropic transport problems. It is found that higher order elements are essential to resolve the thin transition layer characteristic of the anisotropic transport equation, particularly when the strong anisotropic direction is not aligned with one of the Cartesian coordinates. The transition layer is measured by the profile width, which is zero for infinite anisotropy. It is shown that only higher order schemes have the ability to make this layer converge towards zero when the anisotropy gets stronger and stronger. Two cases are considered. One has the strong transport direction partially aligned with one of the element edges, the other doesn't have any alignment. Both cases have the strong transport direction misaligned with the grid line by some angles

An Algorithm for Higher Order Hopf Normal Forms

Directory of Open Access Journals (Sweden)

A.Y.T. Leung

1995-01-01

Full Text Available Normal form theory is important for studying the qualitative behavior of nonlinear oscillators. In some cases, higher order normal forms are required to understand the dynamic behavior near an equilibrium or a periodic orbit. However, the computation of high-order normal forms is usually quite complicated. This article provides an explicit formula for the normalization of nonlinear differential equations. The higher order normal form is given explicitly. Illustrative examples include a cubic system, a quadratic system and a Duffing–Van der Pol system. We use exact arithmetic and find that the undamped Duffing equation can be represented by an exact polynomial differential amplitude equation in a finite number of terms.

Higher-Order Hybrid Gaussian Kernel in Meshsize Boosting Algorithm

African Journals Online (AJOL)

In this paper, we shall use higher-order hybrid Gaussian kernel in a meshsize boosting algorithm in kernel density estimation. Bias reduction is guaranteed in this scheme like other existing schemes but uses the higher-order hybrid Gaussian kernel instead of the regular fixed kernels. A numerical verification of this scheme ...

Higher Order and Fractional Diffusive Equations

Directory of Open Access Journals (Sweden)

D. Assante

2015-07-01

Full Text Available We discuss the solution of various generalized forms of the Heat Equation, by means of different tools ranging from the use of Hermite-Kampé de Fériet polynomials of higher and fractional order to operational techniques. We show that these methods are useful to obtain either numerical or analytical solutions.

Generating higher-order Lie algebras by expanding Maurer-Cartan forms

International Nuclear Information System (INIS)

Caroca, R.; Merino, N.; Salgado, P.; Perez, A.

2009-01-01

By means of a generalization of the Maurer-Cartan expansion method, we construct a procedure to obtain expanded higher-order Lie algebras. The expanded higher-order Maurer-Cartan equations for the case G=V 0 +V 1 are found. A dual formulation for the S-expansion multialgebra procedure is also considered. The expanded higher-order Maurer-Cartan equations are recovered from S-expansion formalism by choosing a special semigroup. This dual method could be useful in finding a generalization to the case of a generalized free differential algebra, which may be relevant for physical applications in, e.g., higher-spin gauge theories.

Modular specification and verification for higher-order languages with state

DEFF Research Database (Denmark)

Svendsen, Kasper

The overall topic of this thesis is modular reasoning for higher-order languages with state. The thesis consists of four mostly independent chapters that each deal with a different aspect of reasoning about higher-order languages with state. The unifying theme throughout all four chapters is higher....... The third chapter of the thesis is a case study of the C# joins library. What makes this library interesting as a case study is that it combines a lot of advanced features (higher-order code with effects, concurrency, recursion through the store, shared mutable state, and fine-grained synchronization...

Finding Higher Order Differentials of MISTY1

Science.gov (United States)

Tsunoo, Yukiyasu; Saito, Teruo; Kawabata, Takeshi; Nakagawa, Hirokatsu

MISTY1 is a 64-bit block cipher that has provable security against differential and linear cryptanalysis. MISTY1 is one of the algorithms selected in the European NESSIE project, and it is recommended for Japanese e-Government ciphers by the CRYPTREC project. In this paper, we report on 12th order differentials in 3-round MISTY1 with FL functions and 44th order differentials in 4-round MISTY1 with FL functions both previously unknown. We also report that both data complexity and computational complexity of higher order differential attacks on 6-round MISTY1 with FL functions and 7-round MISTY1 with FL functions using the 46th order differential can be reduced to as much as 1/22 of the previous values by using multiple 44th order differentials simultaneously.

Practical implementation of a higher order transverse leakage approximation

International Nuclear Information System (INIS)

Prinsloo, Rian H.; Tomašević

2011-01-01

Transverse integrated nodal diffusion methods currently represent the standard in full core neutronic simulation. The primary shortcoming in this approach, be it via the Analytic Nodal Method or Nodal Expansion Method, is the utilization of the quadratic transverse leakage approximation. This approach, although proven to work well for typical LWR problems, is not consistent with the formulation of nodal methods and can cause accuracy and convergence problems. In this work an improved, consistent quadratic leakage approximation is formulated, which derives from the class of higher order nodal methods developed some years ago. In this new approach, only information relevant to describing the transverse leak- age terms in the zero-order nodal equations are obtained from the higher order formalism. The method yields accuracy comparable to full higher order methods, but does not suffer from the same computational burden which these methods typically incur. (author)

Higher class groups of Eichler orders

International Nuclear Information System (INIS)

Guo Xuejun; Kuku, Aderemi

2003-11-01

In this paper, we prove that if A is a quaternion algebra and Λ an Eichler order in A, then the only p-torsion possible in even dimensional higher class groups Cl 2n (Λ) (n ≥ 1) are for those rational primes p which lie under prime ideals of O F at which Λ are not maximal. (author)

Higher-Order Integral Equation Methods in Computational Electromagnetics

DEFF Research Database (Denmark)

Jørgensen, Erik; Meincke, Peter

Higher-order integral equation methods have been investigated. The study has focused on improving the accuracy and efficiency of the Method of Moments (MoM) applied to electromagnetic problems. A new set of hierarchical Legendre basis functions of arbitrary order is developed. The new basis...

Time-Discrete Higher-Order ALE Formulations: Stability

KAUST Repository

Bonito, Andrea

2013-01-01

Arbitrary Lagrangian Eulerian (ALE) formulations deal with PDEs on deformable domains upon extending the domain velocity from the boundary into the bulk with the purpose of keeping mesh regularity. This arbitrary extension has no effect on the stability of the PDE but may influence that of a discrete scheme. We examine this critical issue for higher-order time stepping without space discretization. We propose time-discrete discontinuous Galerkin (dG) numerical schemes of any order for a time-dependent advection-diffusion-model problem in moving domains, and study their stability properties. The analysis hinges on the validity of the Reynold\\'s identity for dG. Exploiting the variational structure and assuming exact integration, we prove that our conservative and nonconservative dG schemes are equivalent and unconditionally stable. The same results remain true for piecewise polynomial ALE maps of any degree and suitable quadrature that guarantees the validity of the Reynold\\'s identity. This approach generalizes the so-called geometric conservation law to higher-order methods. We also prove that simpler Runge-Kutta-Radau methods of any order are conditionally stable, that is, subject to a mild ALE constraint on the time steps. Numerical experiments corroborate and complement our theoretical results. © 2013 Society for Industrial and Applied Mathematics.

The Higher Order Structure of Environmental Attitudes: A Cross-Cultural Examination

Directory of Open Access Journals (Sweden)

Taciano L. Milfont

2010-01-01

Full Text Available Past research has suggested that Preservation and Utilization are the two higher order dimensions forming the hierarchical structure of environmental attitudes. This means that these two higher order dimensions could group all kinds of perceptions or beliefs regarding the natural environment people have. A crosscultural study was conducted in Brazil, New Zealand, and South Africa to test this hierarchical structure of environmental attitudes. Results from single- and multi-group confirmatory factor analyses demonstrated that environmental attitudes are a multidimensional construct, and that their first-order factors associate to each other to form a vertical structure. However, the question whether the vertical structure comprise a single higher order factor or two higher order factors still remains unanswered. These results are discussed and directions for future research trying to demonstrate that Preservation and Utilization, taken as distinct second-order environmental attitudes factors, are more empirically meaningful than a single and generalised environmental attitudes higher order factor are presented.

Higher-order stochastic differential equations and the positive Wigner function

Science.gov (United States)

Drummond, P. D.

2017-12-01

General higher-order stochastic processes that correspond to any diffusion-type tensor of higher than second order are obtained. The relationship of multivariate higher-order stochastic differential equations with tensor decomposition theory and tensor rank is explained. Techniques for generating the requisite complex higher-order noise are proved to exist either using polar coordinates and γ distributions, or from products of Gaussian variates. This method is shown to allow the calculation of the dynamics of the Wigner function, after it is extended to a complex phase space. The results are illustrated physically through dynamical calculations of the positive Wigner distribution for three-mode parametric downconversion, widely used in quantum optics. The approach eliminates paradoxes arising from truncation of the higher derivative terms in Wigner function time evolution. Anomalous results of negative populations and vacuum scattering found in truncated Wigner quantum simulations in quantum optics and Bose-Einstein condensate dynamics are shown not to occur with this type of stochastic theory.

Higher-order gravity in higher dimensions: geometrical origins of four-dimensional cosmology?

Energy Technology Data Exchange (ETDEWEB)

Troisi, Antonio [Universita degli Studi di Salerno, Dipartimento di Fisica ' ' E.R. Caianiello' ' , Salerno (Italy)

2017-03-15

Determining the cosmological field equations is still very much debated and led to a wide discussion around different theoretical proposals. A suitable conceptual scheme could be represented by gravity models that naturally generalize Einstein theory like higher-order gravity theories and higher-dimensional ones. Both of these two different approaches allow one to define, at the effective level, Einstein field equations equipped with source-like energy-momentum tensors of geometrical origin. In this paper, the possibility is discussed to develop a five-dimensional fourth-order gravity model whose lower-dimensional reduction could provide an interpretation of cosmological four-dimensional matter-energy components. We describe the basic concepts of the model, the complete field equations formalism and the 5-D to 4-D reduction procedure. Five-dimensional f(R) field equations turn out to be equivalent, on the four-dimensional hypersurfaces orthogonal to the extra coordinate, to an Einstein-like cosmological model with three matter-energy tensors related with higher derivative and higher-dimensional counter-terms. By considering the gravity model with f(R) = f{sub 0}R{sup n} the possibility is investigated to obtain five-dimensional power law solutions. The effective four-dimensional picture and the behaviour of the geometrically induced sources are finally outlined in correspondence to simple cases of such higher-dimensional solutions. (orig.)

Higher-order chaotic oscillator using active bessel filter

DEFF Research Database (Denmark)

Lindberg, Erik; Mykolaitis, Gytis; Bumelien, Skaidra

2010-01-01

A higher-order oscillator, including a nonlinear unit and an 8th-order low-pass active Bessel filter is described. The Bessel unit plays the role of "three-in-one": a delay line, an amplifier and a filter. Results of hardware experiments and numerical simulation are presented. Depending...

Higher order multipoles and splines in plasma simulations

International Nuclear Information System (INIS)

Okuda, H.; Cheng, C.Z.

1978-01-01

The reduction of spatial grid effects in plasma simulations has been studied numerically using higher order multipole expansions and the spline method in one dimension. It is found that, while keeping the higher order moments such as quadrupole and octopole moments substantially reduces the grid effects, quadratic and cubic splines in general have better stability properties for numerical plasma simulations when the Debye length is much smaller than the grid size. In particular the spline method may be useful in three-dimensional simulations for plasma confinement where the grid size in the axial direction is much greater than the Debye length. (Auth.)

Higher-order multipoles and splines in plasma simulations

International Nuclear Information System (INIS)

Okuda, H.; Cheng, C.Z.

1977-12-01

Reduction of spatial grid effects in plasma simulations has been studied numerically using higher order multipole expansions and spline method in one dimension. It is found that, while keeping the higher order moments such as quadrupole and octopole moments substantially reduces the grid effects, quadratic and cubic splines in general have better stability properties for numerical plasma simulations when the Debye length is much smaller than the grid size. In particular, spline method may be useful in three dimensional simulations for plasma confinement where the grid size in the axial direction is much greater than the Debye length

Higher-order dynamical effects in Coulomb dissociation

International Nuclear Information System (INIS)

Esbensen, H.

1994-06-01

We study the effect of higher-order processes in Coulomb dissociation of 11 Li by numerically solving the three-dimensional time-dependent Schroedinger equation for the relative motion of a di-neutron and the 9 Li core. Comparisons are made to first-order perturbation theory and to measurements. The calculated Coulomb reacceleration effects improve the agreement with experiment, but some discrepancy remains. The effects are much smaller in the dissociation of 11 Be, and they decrease with increasing beam energy. (orig.)

Higher Order Mode Fibers

DEFF Research Database (Denmark)

Israelsen, Stine Møller

This PhD thesis considers higher order modes (HOMs) in optical fibers. That includes their excitation and characteristics. Within the last decades, HOMs have been applied both for space multiplexing in optical communications, group velocity dispersion management and sensing among others......-radial polarization as opposed to the linear polarization of the LP0X modes. The effect is investigated numerically in a double cladding fiber with an outer aircladding using a full vectorial modesolver. Experimentally, the bowtie modes are excited using a long period grating and their free space characteristics...... and polarization state are investigated. For this fiber, the onset of the bowtie effect is shown numerically to be LP011. The characteristics usually associated with Bessel-likes modes such as long diffraction free length and selfhealing are shown to be conserved despite the lack of azimuthal symmetry...

Extension of relativistic dissipative hydrodynamics to third order

International Nuclear Information System (INIS)

El, Andrej; Xu Zhe; Greiner, Carsten

2010-01-01

Following the procedure introduced by Israel and Stewart, we expand the entropy current up to the third order in the shear stress tensor π αβ and derive a novel third-order evolution equation for π αβ . This equation is solved for the one-dimensional Bjorken boost-invariant expansion. The scaling solutions for various values of the shear viscosity to the entropy density ratio η/s are shown to be in very good agreement with those obtained from kinetic transport calculations. For the pressure isotropy starting with 1 at τ 0 =0.4 fm/c, the third-order corrections to Israel-Stewart theory are approximately 10% for η/s=0.2 and more than a factor of 2 for η/s=3. We also estimate all higher-order corrections to Israel-Stewart theory and demonstrate their importance in describing highly viscous matters.

Interactions, strings and isotopies in higher order anisotropic superspaces

CERN Document Server

Vacaru, Sergiu Ion

2001-01-01

The monograph summarizes the author's results on the geometry of anholonomic and locally anisotropic interactions, published in J. Math. Phys., Nucl. Phys. B, Ann. Phys. (NY), JHEP, Rep. Math. Phys., Int. J. Theor. Phys. and in some former Soviet Union and Romanian scientific journals. The main subjects are in the theory of field interactions, strings and diffusion processes on spaces, superspaces and isospaces with higher order anisotropy and inhomogeneity. The approach proceeds by developing the concept of higher order anisotropic (super)space which unifies the logical and manthematical aspects of modern Kaluza--Klein theories and generalized Lagrange and Finsler geometry and leads to modeling of physical processes on higher order fiber (super)bundles provided with nonlinear and distinguished connections and metric structures. This book can be also considered as a pedagogical survey on the mentioned subjects.

The differential geometry of higher order jets and tangent bundles

International Nuclear Information System (INIS)

De Leon, M.; Rodrigues, P.R.

1985-01-01

This chapter is devoted to the study of basic geometrical notions required for the development of the main object of the text. Some facts about Jet theory are reviewed. A particular case of Jet manifolds is considered: the tangent bundle of higher order. It is shown that this jet bundle possesses in a canonical way a certain kind of geometric structure, the so called almost tangent structure of higher order, and which is a generalization of the almost tangent geometry of the tangent bundle. Another important fact examined is the extension of the notion of 'spray' to higher order tangent bundles. (Auth.)

Shear-induced Long Range Order in Diblock Copolymer Thin Films

Science.gov (United States)

Ding, Xuan; Russell, Thomas

2007-03-01

Shear is a well-established means of aligning block copolymer micro-domains in bulk; cylinder-forming block copolymers respond by orienting cylinder axes parallel to the flow direction, and macroscopic specimens with near-single-crystal texture can be obtained. A stepper motor is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps. With the combination of a stepper motor and several gear boxes in our experiment, we can control the rotating resolution to be as small as 1 x10-4 degree/step. Also, with the help of a customized computer program we can control the motor speed in a very systematical way. By changing parameters such as the weight (or the uniform pressure) and the lateral force we can carry on experiment to examine the effect of lateral shear on different polymer systems such as PS-b-PEO (large χ) and PS-b-P2VP (small χ).

Linear matrix differential equations of higher-order and applications

Directory of Open Access Journals (Sweden)

Mustapha Rachidi

2008-07-01

Full Text Available In this article, we study linear differential equations of higher-order whose coefficients are square matrices. The combinatorial method for computing the matrix powers and exponential is adopted. New formulas representing auxiliary results are obtained. This allows us to prove properties of a large class of linear matrix differential equations of higher-order, in particular results of Apostol and Kolodner are recovered. Also illustrative examples and applications are presented.

Higher order corrections in quantum electrodynamics

International Nuclear Information System (INIS)

Rafael, E.

1977-01-01

Theoretical contributions to high-order corrections in purely leptonic systems, such as electrons and muons, muonium (μ + e - ) and positronium (e + e - ), are reviewed to establish the validity of quantum electrodynamics (QED). Two types of QED contributions to the anomalous magnetic moments are considered, from diagrams with one fermion type lines and those witn two fermion type lines. The contributions up to eighth order are compared to the data available with a different accuracy. Good agreement is stated within the experimental errors. The experimental accuracy of the muonium hyperfine structure and of the radiative corrections to the decay of positronium are compared to the one attainable in theoretical calculations. The need for a higher precision in both experimental data and theoretical calculations is stated

Errors of first-order probe correction for higher-order probes in spherical near-field antenna measurements

DEFF Research Database (Denmark)

Laitinen, Tommi; Nielsen, Jeppe Majlund; Pivnenko, Sergiy

2004-01-01

An investigation is performed to study the error of the far-field pattern determined from a spherical near-field antenna measurement in the case where a first-order (mu=+-1) probe correction scheme is applied to the near-field signal measured by a higher-order probe.......An investigation is performed to study the error of the far-field pattern determined from a spherical near-field antenna measurement in the case where a first-order (mu=+-1) probe correction scheme is applied to the near-field signal measured by a higher-order probe....

Shear banding, discontinuous shear thickening, and rheological phase transitions in athermally sheared frictionless disks

Science.gov (United States)

Vâgberg, Daniel; Olsson, Peter; Teitel, S.

2017-05-01

We report on numerical simulations of simple models of athermal, bidisperse, soft-core, massive disks in two dimensions, as a function of packing fraction ϕ , inelasticity of collisions as measured by a parameter Q , and applied uniform shear strain rate γ ˙. Our particles have contact interactions consisting of normally directed elastic repulsion and viscous dissipation, as well as tangentially directed viscous dissipation, but no interparticle Coulombic friction. Mapping the phase diagram in the (ϕ ,Q ) plane for small γ ˙, we find a sharp first-order rheological phase transition from a region with Bagnoldian rheology to a region with Newtonian rheology, and show that the system is always Newtonian at jamming. We consider the rotational motion of particles and demonstrate the crucial importance that the coupling between rotational and translational degrees of freedom has on the phase structure at small Q (strongly inelastic collisions). At small Q , we show that, upon increasing γ ˙, the sharp Bagnoldian-to-Newtonian transition becomes a coexistence region of finite width in the (ϕ ,γ ˙) plane, with coexisting Bagnoldian and Newtonian shear bands. Crossing this coexistence region by increasing γ ˙ at fixed ϕ , we find that discontinuous shear thickening can result if γ ˙ is varied too rapidly for the system to relax to the shear-banded steady state corresponding to the instantaneous value of γ ˙.

Analysis of the Shear Behavior of Stubby Y-Type Perfobond Rib Shear Connectors for a Composite Frame Structure.

Science.gov (United States)

Kim, Sang-Hyo; Kim, Kun-Soo; Lee, Do-Hoon; Park, Jun-Seung; Han, Oneil

2017-11-22

Shear connectors are used in steel beam-concrete slabs of composite frame and bridge structures to transfer shear force according to design loads. The existing Y-type perfobond rib shear connectors are designed for girder slabs of composite bridges. Therefore, the rib and transverse rebars of the conventional Y-type perfobond rib shear connectors are extremely large for the composite frames of building structures. Thus, this paper proposes stubby Y-type perfobond rib shear connectors, redefining the existing connectors, for composite frames of building structures; these were used to perform push-out tests. These shear connectors have relatively small ribs compared to the conventional Y-type perfobond rib shear connectors. To confirm the shear resistance of these stubby shear connectors, we performed an experiment by using transverse rebars D13 and D16. The results indicate that these shear connectors have suitable shear strength and ductility for application in composite frame structures. The shear strengths obtained using D13 and D16 were not significantly different. However, the ductility of the shear connectors with D16 was 45.1% higher than that of the shear connectors with D13.

MIMO processing based on higher-order Poincaré spheres

Science.gov (United States)

Fernandes, Gil M.; Muga, Nelson J.; Pinto, Armando N.

2017-08-01

A multi-input multi-output (MIMO) algorithm based on higher-order Poincaré spheres is demonstrated for space-division multiplexing (SDM) systems. The MIMO algorithm is modulation format agnostic, robust to frequency offset and does not require training sequences. In this approach, the space-multiplexed signal is decomposed in sets of two tributary signals, with each set represented in a higher-order Poincaré sphere. For any arbitrary complex modulation format, the samples of two tributaries can be represented in a given higher-order Poincaré sphere with a symmetry plane. The crosstalk along propagation changes the spatial orientation of this plane and, therefore, it can be compensated by computing and realigning the best fit plane. We show how the transmitted signal can be successfully recovered using this procedure for all possible combinations of tributaries. Moreover, we analyze the convergence speed for the MIMO technique considering several optical-to-noise ratios.

Ballooning mode stabilization by moderate sheared rotation

International Nuclear Information System (INIS)

Hameiri, E.

1996-01-01

Sheared toroidal plasma rotation has been known for some time to have a stabilizing effect on the ballooning modes. A recent calculation showed that a large flow shear, with dΩ/dq of the order of the Alfven toroidal frequency, can stabilize the ballooning modes. This latest result is, in fact, not so optimistic. For observed flows with Mach number of order unity one gets dΩ/dq smaller by a factor O(√β) from the required level (if the flow shear length is of the same order as the magnetic shear length). Moreover, the calculation does not take into account a possibly large transient growth of the mode amplitude due to its Floquet structures We show here that, in fact, there is a general tendency of the ballooning mode to stabilize as soon as the flow shear dΩ/dq exceeds the (O√β smaller) open-quotes slowclose quotes magnetosonic wave frequency. Our analysis is perturbative, where the small parameter is related to the small coupling between the slow and Alfven waves-as is the case in a high aspect-ratio tokamak. (In the perturbation it is important to take the Hamiltonian nature of the governing equations into account.) Moreover, our results apply to the relevant transient growth of the mode amplitude

Ward identities of higher order Virasoro algebra

International Nuclear Information System (INIS)

Zha Chaozeng; Dolate, S.

1994-11-01

The general formulations of primary fields versus quasi-primary ones in the context of high order Virasoro algebra (HOVA) and the corresponding Ward identity are explored. The primary fields of conformal spins up to 8 are given in terms of quasi-primary fields, and the general features of the higher order expressions are also discussed. It is observed that the local fields, either primary of quasi-primary, carry the same numbers of central charges, and not all the primary fields contribute to the anomalies in the Ward identities. (author). 6 refs

Higher order perturbation theory - An example for discussion

International Nuclear Information System (INIS)

Lewins, J.D.; Parks, G.; Babb, A.L.

1986-01-01

Higher order perturbation theory is developed in the form of a Taylor series expansion to third order to calculate the thermal utilization of a nonuniform cell. The development takes advantage of the self-adjoint property of the diffusion operator to provide a simple development of this illustration of generalized perturbation theory employing scalar perturbation parameters. The results show how a designer might employ a second-order theory to quantify proposed design improvements, together with the limitations of second- and third-order theory. The chosen example has an exact optimization solution and thus provides a clear understanding of the role of perturbation theory at its various orders. Convergence and the computational advantages and disadvantages of the method are discussed

Application of Higher-Order Cumulant in Fault Diagnosis of Rolling Bearing

International Nuclear Information System (INIS)

Shen, Yongjun; Yang, Shaopu; Wang, Junfeng

2013-01-01

In this paper a new method of pattern recognition based on higher-order cumulant and envelope analysis is presented. The core of this new method is to construct analytical signals from the given signals and obtain the envelope signals firstly, then compute and compare the higher-order cumulants of the envelope signals. The higher-order cumulants could be used as a characteristic quantity to distinguish these given signals. As an example, this method is applied in fault diagnosis for 197726 rolling bearing of freight locomotive. The comparisons of the second-order, third-order and fourth-order cumulants of the envelope signals from different vibration signals of rolling bearing show this new method could discriminate the normal and two fault signals distinctly

Higher-order risk preferences in social settings.

Science.gov (United States)

Heinrich, Timo; Mayrhofer, Thomas

2018-01-01

We study prudence and temperance (next to risk aversion) in social settings. Previous experimental studies have shown that these higher-order risk preferences affect the choices of individuals deciding privately on lotteries that only affect their own payoff. Yet, many risky and financially relevant decisions are made in the social settings of households or organizations. We elicit higher-order risk preferences of individuals and systematically vary how an individual's decision is made (alone or while communicating with a partner) and who is affected by the decision (only the individual or the partner as well). In doing so, we can isolate the effects of other-regarding concerns and communication on choices. Our results reveal that the majority of choices are risk averse, prudent, and temperate across social settings. We also observe that individuals are influenced significantly by the preferences of a partner when they are able to communicate and choices are payoff-relevant for both of them.

Mathematics Teachers’ Interpretation of Higher-Order Thinking in Bloom’s Taxonomy

OpenAIRE

Tony Thompson

2008-01-01

This study investigated mathematics teachers’ interpretation of higher-order thinking in Bloom’s Taxonomy. Thirty-two high school mathematics teachers from the southeast U.S. were asked to (a) define lower- and higher-order thinking, (b) identify which thinking skills in Bloom’s Taxonomy represented lower- and higher-order thinking, and (c) create an Algebra I final exam item representative of each thinking skill. Results indicate that mathematics teachers have difficulty interpreting the thi...

Surface acoustic load sensing using a face-shear PIN-PMN-PT single-crystal resonator.

Science.gov (United States)

Kim, Kyungrim; Zhang, Shujun; Jiang, Xiaoning

2012-11-01

Pb(In(0.5)Nb(0.5))O(3)-Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) (PIN-PMN-PT) resonators for surface acoustic load sensing are presented in this paper. Different acoustic loads are applied to thickness mode, thickness-shear mode, and face-shear mode resonators, and the electrical impedances at resonance and anti-resonance frequencies are recorded. More than one order of magnitude higher sensitivity (ratio of electrical impedance change to surface acoustic impedance change) at the resonance is achieved for the face-shear-mode resonator compared with other resonators with the same dimensions. The Krimholtz, Leedom, and Matthaei (KLM) model is used to verify the surface acoustic loading effect on the electrical impedance spectrum of face-shear PIN-PMN-PT single-crystal resonators. The demonstrated high sensitivity of face-shear mode resonators to surface loads is promising for a broad range of applications, including artificial skin, biological and chemical sensors, touch screens, and other touch-based sensors.

Higher-Order Finite Element Solutions of Option Prices

DEFF Research Database (Denmark)

Raahauge, Peter

2004-01-01

Kinks and jumps in the payoff function of option contracts prevent an effectiveimplementation of higher-order numerical approximation methods. Moreover, thederivatives (the greeks) are not easily determined around such singularities, even withstandard lower-order methods. This paper suggests...... for prices as well as for first and second order derivatives(delta and gamma). Unlike similar studies, numerical approximation errors aremeasured both as weighted averages and in the supnorm over a state space includingtime-to-maturities down to a split second.KEYWORDS: Numerical option pricing, Transformed...

The Cauchy problem for higher order abstract differential equations

CERN Document Server

Xiao, Ti-Jun

1998-01-01

This monograph is the first systematic exposition of the theory of the Cauchy problem for higher order abstract linear differential equations, which covers all the main aspects of the developed theory. The main results are complete with detailed proofs and established recently, containing the corresponding theorems for first and incomplete second order cases and therefore for operator semigroups and cosine functions. They will find applications in many fields. The special power of treating the higher order problems directly is demonstrated, as well as that of the vector-valued Laplace transforms in dealing with operator differential equations and operator families. The reader is expected to have a knowledge of complex and functional analysis.

Comparing higher order models for the EORTC QLQ-C30

DEFF Research Database (Denmark)

Gundy, Chad M; Fayers, Peter M; Grønvold, Mogens

2012-01-01

To investigate the statistical fit of alternative higher order models for summarizing the health-related quality of life profile generated by the EORTC QLQ-C30 questionnaire.......To investigate the statistical fit of alternative higher order models for summarizing the health-related quality of life profile generated by the EORTC QLQ-C30 questionnaire....

Scalar brane backgrounds in higher order curvature gravity

International Nuclear Information System (INIS)

Charmousis, Christos; Davis, Stephen C.; Dufaux, Jean-Francois

2003-01-01

We investigate maximally symmetric brane world solutions with a scalar field. Five-dimensional bulk gravity is described by a general lagrangian which yields field equations containing no higher than second order derivatives. This includes the Gauss-Bonnet combination for the graviton. Stability and gravitational properties of such solutions are considered, and we particularly emphasise the modifications induced by the higher order terms. In particular it is shown that higher curvature corrections to Einstein theory can give rise to instabilities in brane world solutions. A method for analytically obtaining the general solution for such actions is outlined. Generically, the requirement of a finite volume element together with the absence of a naked singularity in the bulk imposes fine-tuning of the brane tension. A model with a moduli scalar field is analysed in detail and we address questions of instability and non-singular self-tuning solutions. In particular, we discuss a case with a normalisable zero mode but infinite volume element. (author)

Higher-order RANS turbulence models for separated flows

Data.gov (United States)

National Aeronautics and Space Administration — Higher-order Reynolds-averaged Navier-Stokes (RANS) models are developed to overcome the shortcomings of second-moment RANS models in predicting separated flows....

Higher order mode damping of a higher harmonic superconducting cavity for SSRF

International Nuclear Information System (INIS)

Yu Haibo; Liu Jianfei; Hou Hongtao; Ma Zhenyu; Feng Xiqiang; Mao Dongqing

2012-01-01

Adopting a higher harmonic cavity on a synchrotron radiation facility can increase the beam lifetime and suppress the beam instability. In this paper, we report the simulation and preliminary design on higher order modes (HOMs) damping of the designed and fabricated higher harmonic superconducting cavity for Shanghai Synchrotron Radiation Facility (SSRF). The requirements for the HOM damping are analyzed, and the length and location of the HOM damper are optimized by using the SEAFISH code. The results show that the design can provide heavy damping for harmful HOMs with decreased impedance, and the beam instability requirement of SSRF can be satisfied. By using the ABCI code, the loss factor is obtained and the HOM power is estimated. (authors)

The power of non-determinism in higher-order implicit complexity

DEFF Research Database (Denmark)

Kop, Cynthia Louisa Martina; Simonsen, Jakob Grue

2017-01-01

We investigate the power of non-determinism in purely functional programming languages with higher-order types. Specifically, we consider cons-free programs of varying data orders, equipped with explicit non-deterministic choice. Cons-freeness roughly means that data constructors cannot occur...... in function bodies and all manipulation of storage space thus has to happen indirectly using the call stack. While cons-free programs have previously been used by several authors to characterise complexity classes, the work on non-deterministic programs has almost exclusively considered programs of data order...... 0. Previous work has shown that adding explicit non-determinism to consfree programs taking data of order 0 does not increase expressivity; we prove that this—dramatically—is not the case for higher data orders: adding non-determinism to programs with data order at least 1 allows...

PRE-SERVICE MATHEMATICS TEACHERS’ CONCEPTION OF HIGHER-ORDER THINKING LEVEL IN BLOOM'S TAXONOMY

OpenAIRE

Damianus D Samo

2017-01-01

The purpose of this study is to explore pre-service mathematics teachers' conception of higher-order thinking in Bloom's Taxonomy, to explore pre-service mathematics teachers' ability in categorizing six cognitive levels of Bloom's Taxonomy as lower-order thinking and higher-order thinking, and pre-service mathematics teachers' ability in identifying some questionable items as lower-order and higher-order thinking. The higher-order thinking is the type of non-algorithm thinking which include ...

Wigner higher-order spectra: definition, properties, computation and application to transient signal analysis

OpenAIRE

Rodríguez Fonollosa, Javier; Nikias, Chrysostomos L.

1993-01-01

The Wigner higher order moment spectra (WHOS) are defined as extensions of the Wigner-Ville distribution (WD) to higher order moment spectra domains. A general class of time-frequency higher order moment spectra is also defined in terms of arbitrary higher order moments of the signal as generalizations of the Cohen’s general class of time-frequency representations. The properties of the general class of time-frequency higher order moment spectra can be related to the properties...

Higher-order Skyrme hair of black holes

Science.gov (United States)

Gudnason, Sven Bjarke; Nitta, Muneto

2018-05-01

Higher-order derivative terms are considered as replacement for the Skyrme term in an Einstein-Skyrme-like model in order to pinpoint which properties are necessary for a black hole to possess stable static scalar hair. We find two new models able to support stable black hole hair in the limit of the Skyrme term being turned off. They contain 8 and 12 derivatives, respectively, and are roughly the Skyrme-term squared and the so-called BPS-Skyrme-term squared. In the twelfth-order model we find that the lower branches, which are normally unstable, become stable in the limit where the Skyrme term is turned off. We check this claim with a linear stability analysis. Finally, we find for a certain range of the gravitational coupling and horizon radius, that the twelfth-order model contains 4 solutions as opposed to 2. More surprisingly, the lowest part of the would-be unstable branch turns out to be the stable one of the 4 solutions.

Hierarchical order in wall-bounded shear turbulence

International Nuclear Information System (INIS)

Carbone, F.; Aubry, N.

1996-01-01

Since turbulence at realistic Reynolds numbers, such as those occurring in the atmosphere or in the ocean, involve a high number of modes that cannot be resolved computationally in the foreseeable future, there is a strong motivation for finding techniques which drastically decrease the number of such required modes, particularly under inhomogeneous conditions. The significance of this work is to show that wall-bounded shear turbulence, in its strongly inhomogeneous direction (normal to the wall), can be decomposed into one (or a few) space endash time mother mode(s), with each mother generating a whole family of modes by stretching symmetry. In other words, the generated modes are similar, dilated copies of their mother. In addition, we show that the nature of all previous modes strongly depends on the symmetry itself. These findings constitute the first scaling theory of inhomogeneous turbulence. copyright 1996 American Institute of Physics

An experimental study of high heat flux removal by shear-driven liquid films

Directory of Open Access Journals (Sweden)

Zaitsev Dmitry

2017-01-01

Full Text Available Intensively evaporating liquid films, moving under the friction of a co-current gas flow in a mini-channel (shear-driven liquid films, are promising for the use in cooling systems of modern semiconductor devices with high local heat release. In this work, the effect of various parameters, such as the liquid and gas flow rates and channel height, on the critical heat flux in the locally heated shear-driven water film has been studied. A record value of the critical heat flux of 1200 W/cm2 has been achieved in experiments. Heat leaks to the substrate and heat losses to the atmosphere in total do not exceed 25% for the heat flux above 400 W/cm2. Comparison of the critical heat fluxes for the shear-driven liquid film and for flow boiling in a minichannel shows that the critical heat flux is an order of magnitude higher for the shear-driven liquid film. This confirms the prospect of using shear-driven liquid films in the modern high-efficient cooling systems.

Higher order mode damping in Kaon factory RF cavities

International Nuclear Information System (INIS)

Enegren, T.; Poirier, R.; Griffin, J.; Walling, L.; Thiessen, H.A.; Smythe, W.R.

1989-05-01

Proposed designs for Kaon factory accelerators require that the rf cavities support beam currents on the order of several amperes. The beam current has Fourier components at all multiples of the rf frequency. Empty rf buckets produce additional components at all multiples of the revolution frequency. If a Fourier component of the beam coincides with the resonant frequency of a higher order mode of the cavity, which is inevitable if the cavity has a large frequency swing, significant excitation of this mode can occur. The induced voltage may then excite coupled bunch mode instabilities. Effective means are required to damp higher order modes without significantly affecting the fundamental mode. A mode damping scheme based on coupled transmission lines has been investigated and is report

Anomalous transport due to shear-Alfven waves

International Nuclear Information System (INIS)

Lee, W.W.; Chance, M.S.; Okuda, H.

1980-10-01

The behavior of shear-Alfven eigenmodes and the accompanied anomalous transport have been investigated. In the particle simulation, equilibrium thermal fluctuations associated with the eigenmodes have been observed to nullify the zeroth-order shear near the rational surface through the induced second-order eddy current, and, in turn, give rise to the formation of magnetic islands which cause rapid electron energy transport in the region. The theoretical verification of the observed behavior is discussed

Higher Order, Hybrid BEM/FEM Methods Applied to Antenna Modeling

Science.gov (United States)

Fink, P. W.; Wilton, D. R.; Dobbins, J. A.

2002-01-01

In this presentation, the authors address topics relevant to higher order modeling using hybrid BEM/FEM formulations. The first of these is the limitation on convergence rates imposed by geometric modeling errors in the analysis of scattering by a dielectric sphere. The second topic is the application of an Incomplete LU Threshold (ILUT) preconditioner to solve the linear system resulting from the BEM/FEM formulation. The final tOpic is the application of the higher order BEM/FEM formulation to antenna modeling problems. The authors have previously presented work on the benefits of higher order modeling. To achieve these benefits, special attention is required in the integration of singular and near-singular terms arising in the surface integral equation. Several methods for handling these terms have been presented. It is also well known that achieving he high rates of convergence afforded by higher order bases may als'o require the employment of higher order geometry models. A number of publications have described the use of quadratic elements to model curved surfaces. The authors have shown in an EFIE formulation, applied to scattering by a PEC .sphere, that quadratic order elements may be insufficient to prevent the domination of modeling errors. In fact, on a PEC sphere with radius r = 0.58 Lambda(sub 0), a quartic order geometry representation was required to obtain a convergence benefi.t from quadratic bases when compared to the convergence rate achieved with linear bases. Initial trials indicate that, for a dielectric sphere of the same radius, - requirements on the geometry model are not as severe as for the PEC sphere. The authors will present convergence results for higher order bases as a function of the geometry model order in the hybrid BEM/FEM formulation applied to dielectric spheres. It is well known that the system matrix resulting from the hybrid BEM/FEM formulation is ill -conditioned. For many real applications, a good preconditioner is required

Higher Order Thinking Skills among Secondary School Students in Science Learning

Science.gov (United States)

Saido, Gulistan Mohammed; Siraj, Saedah; Bin Nordin, Abu Bakar; Al Amedy, Omed Saadallah

2015-01-01

A central goal of science education is to help students to develop their higher order thinking skills to enable them to face the challenges of daily life. Enhancing students' higher order thinking skills is the main goal of the Kurdish Science Curriculum in the Iraqi-Kurdistan region. This study aimed at assessing 7th grade students' higher order…

Student's Perceived Level and Teachers' Teaching Strategies of Higher Order Thinking Skills: A Study on Higher Educational Institutions in Thailand

Science.gov (United States)

Shukla, Divya; Dungsungnoen, Aj Pattaradanai

2016-01-01

Higher order thinking skills (HOTS) has portrayed immense industry demand and the major goal of educational institution in imparting education is to inculcate higher order thinking skills. This compiles and mandate the institutions and instructor to develop the higher order thinking skills among students in order to prepare them for effective…

Separation of gravitational-wave and cosmic-shear contributions to cosmic microwave background polarization.

Science.gov (United States)

Kesden, Michael; Cooray, Asantha; Kamionkowski, Marc

2002-07-01

Inflationary gravitational waves (GW) contribute to the curl component in the polarization of the cosmic microwave background (CMB). Cosmic shear--gravitational lensing of the CMB--converts a fraction of the dominant gradient polarization to the curl component. Higher-order correlations can be used to map the cosmic shear and subtract this contribution to the curl. Arcminute resolution will be required to pursue GW amplitudes smaller than those accessible by the Planck surveyor mission. The blurring by lensing of small-scale CMB power leads with this reconstruction technique to a minimum detectable GW amplitude corresponding to an inflation energy near 10(15) GeV.

Microfluidic thrombosis under multiple shear rates and antiplatelet therapy doses.

Directory of Open Access Journals (Sweden)

Melissa Li

Full Text Available The mainstay of treatment for thrombosis, the formation of occlusive platelet aggregates that often lead to heart attack and stroke, is antiplatelet therapy. Antiplatelet therapy dosing and resistance are poorly understood, leading to potential incorrect and ineffective dosing. Shear rate is also suspected to play a major role in thrombosis, but instrumentation to measure its influence has been limited by flow conditions, agonist use, and non-systematic and/or non-quantitative studies. In this work we measured occlusion times and thrombus detachment for a range of initial shear rates (500, 1500, 4000, and 10000 s(-1 and therapy concentrations (0-2.4 µM for eptifibatide, 0-2 mM for acetyl-salicylic acid (ASA, 3.5-40 Units/L for heparin using a microfluidic device. We also measured complete blood counts (CBC and platelet activity using whole blood impedance aggregometry. Effects of shear rate and dose were analyzed using general linear models, logistic regressions, and Cox proportional hazards models. Shear rates have significant effects on thrombosis/dose-response curves for all tested therapies. ASA has little effect on high shear occlusion times, even at very high doses (up to 20 times the recommended dose. Under ASA therapy, thrombi formed at high shear rates were 4 times more prone to detachment compared to those formed under control conditions. Eptifibatide reduced occlusion when controlling for shear rate and its efficacy increased with dose concentration. In contrast, the hazard of occlusion from ASA was several orders of magnitude higher than that of eptifibatide. Our results show similar dose efficacy to our low shear measurements using whole blood aggregometry. This quantitative and statistically validated study of the effects of a wide range of shear rate and antiplatelet therapy doses on occlusive thrombosis contributes to more accurate understanding of thrombosis and to models for optimizing patient treatment.

Model tests on dynamic performance of RC shear walls

International Nuclear Information System (INIS)

Nagashima, Toshio; Shibata, Akenori; Inoue, Norio; Muroi, Kazuo.

1991-01-01

For the inelastic dynamic response analysis of a reactor building subjected to earthquakes, it is essentially important to properly evaluate its restoring force characteristics under dynamic loading condition and its damping performance. Reinforced concrete shear walls are the main structural members of a reactor building, and dominate its seismic behavior. In order to obtain the basic information on the dynamic restoring force characteristics and damping performance of shear walls, the dynamic test using a large shaking table, static displacement control test and the pseudo-dynamic test on the models of a shear wall were conducted. In the dynamic test, four specimens were tested on a large shaking table. In the static test, four specimens were tested, and in the pseudo-dynamic test, three specimens were tested. These tests are outlined. The results of these tests were compared, placing emphasis on the restoring force characteristics and damping performance of the RC wall models. The strength was higher in the dynamic test models than in the static test models mainly due to the effect of loading rate. (K.I.)

Comparison of direct shear and simple shear responses of municipal solid waste in USA

KAUST Repository

Fei, Xunchang

2017-10-25

Although large-size simple shear (SS) testing of municipal solid waste (MSW) may arguably provide a more realistic estimate of the shear strength (τ ) of MSW than the most commonly used direct shear (DS) testing, a systematic comparison between the shear responses of MSW obtained from the two testing methods is lacking. In this study, a large-size shear device was used to test identical MSW specimens sampled in USA in DS and SS. Eight DS tests and 11 SS tests were conducted at vertical effective stresses of 50–500 kPa. The stress–displacement response of MSW in SS testing was hyperbolic and a maximum shear stress was reached, whereas a maximum shear stress was not reached in most DS tests. The τ, effective friction angle (ϕ ′) and cohesion (c ′) of MSW were obtained from DS and SS tests by using a displacement failure criterion of 40 mm. τ in SS testing was found to be equal to or lower than τ in DS testing with ratios of τ between 73 and 101%. SS testing resulted in higher ϕ ′ but lower c ′ than DS testing. The shear strength parameters were lower than those obtained in previous studies from DS tests at 55 mm displacement.

Verifying object-oriented programs with higher-order separation logic in Coq

DEFF Research Database (Denmark)

Bengtson, Jesper; Jensen, Jonas Braband; Sieczkowski, Filip

2011-01-01

We present a shallow Coq embedding of a higher-order separation logic with nested triples for an object-oriented programming language. Moreover, we develop novel specification and proof patterns for reasoning in higher-order separation logic with nested triples about programs that use interfaces...... and interface inheritance. In particular, we show how to use the higher-order features of the Coq formalisation to specify and reason modularly about programs that (1) depend on some unknown code satisfying a specification or that (2) return objects conforming to a certain specification. All of our results have...

Higher-order structure of Saccharomyces cerevisiae chromatin

International Nuclear Information System (INIS)

Lowary, P.T.; Widom, J.

1989-01-01

We have developed a method for partially purifying chromatin from Saccharomyces cerevisiae (baker's yeast) to a level suitable for studies of its higher-order folding. This has required the use of yeast strains that are free of the ubiquitous yeast killer virus. Results from dynamic light scattering, electron microscopy, and x-ray diffraction show that the yeast chromatin undergoes a cation-dependent folding into 30-nm filaments that resemble those characteristic of higher-cell chromatin; moreover, the packing of nucleosomes within the yeast 30-nm filaments is similar to that of higher cells. These results imply that yeast has a protein or protein domain that serves the role of the histone H 1 found in higher cells; physical and genetic studies of the yeast activity could help elucidate the structure and function of H 1. Images of the yeast 30-nm filaments can be used to test crossed-linker models for 30-nm filament structure

Higher-order force moments of active particles

Science.gov (United States)

Nasouri, Babak; Elfring, Gwynn J.

2018-04-01

Active particles moving through fluids generate disturbance flows due to their activity. For simplicity, the induced flow field is often modeled by the leading terms in a far-field approximation of the Stokes equations, whose coefficients are the force, torque, and stresslet (zeroth- and first-order force moments) of the active particle. This level of approximation is quite useful, but may also fail to predict more complex behaviors that are observed experimentally. In this study, to provide a better approximation, we evaluate the contribution of the second-order force moments to the flow field and, by reciprocal theorem, present explicit formulas for the stresslet dipole, rotlet dipole, and potential dipole for an arbitrarily shaped active particle. As examples of this method, we derive modified Faxén laws for active spherical particles and resolve higher-order moments for active rod-like particles.

Analysis and Improvement of the Generic Higher-Order Masking Scheme of FSE 2012

OpenAIRE

Roy, Arnab; Venkatesh, Srinivas Vivek

2013-01-01

Masking is a well-known technique used to prevent block cipher implementations from side-channel attacks. Higher-order side channel attacks (e.g. higher-order DPA attack) on widely used block cipher like AES have motivated the design of efficient higher-order masking schemes. Indeed, it is known that as the masking order increases, the difficulty of side-channel attack increases exponentially. However, the main problem in higher-order masking is to design an efficient and secure technique for...

Recurrent activity in higher order, modality non-specific brain regions

DEFF Research Database (Denmark)

Lou, Hans Olav Christensen; Joensson, Morten; Biermann-Ruben, Katja

2011-01-01

It has been proposed that the workings of the brain are mainly intrinsically generated recurrent neuronal activity, with sensory inputs as modifiers of such activity in both sensory and higher order modality non-specific regions. This is supported by the demonstration of recurrent neuronal activity...... in the visual system as a response to visual stimulation. In contrast recurrent activity has never been demonstrated before in higher order modality non-specific regions. Using magneto-encephalography and Granger causality analysis, we tested in a paralimbic network the hypothesis that stimulation may enhance...... causal recurrent interaction between higher-order, modality non-specific regions. The network includes anterior cingulate/medial prefrontal and posterior cingulate/medial parietal cortices together with pulvinar thalami, a network known to be effective in autobiographic memory retrieval and self...

Visualization and processing of higher order descriptors for multi-valued data

CERN Document Server

Schultz, Thomas

2015-01-01

Modern imaging techniques and computational simulations yield complex multi-valued data that require higher-order mathematical descriptors. This book addresses topics of importance when dealing with such data, including frameworks for image processing, visualization, and statistical analysis of higher-order descriptors. It also provides examples of the successful use of higher-order descriptors in specific applications and a glimpse of the next generation of diffusion MRI. To do so, it combines contributions on new developments, current challenges in this area, and state-of-the-art surveys.   Compared to the increasing importance of higher-order descriptors in a range of applications, tools for analysis and processing are still relatively hard to come by. Even though application areas such as medical imaging, fluid dynamics, and structural mechanics are very different in nature they face many shared challenges. This book provides an interdisciplinary perspective on this topic with contributions from key rese...

Structural damage detection using higher-order finite elements and a scanning laser vibrometer

Science.gov (United States)

Jin, Si

In contrast to conventional non-destructive evaluation methods, dynamics-based damage detection methods are capable of rapid integrity evaluation of large structures and have received considerable attention from aerospace, mechanical, and civil engineering communities in recent years. However, the identifiable damage size using dynamics-based methods is determined by the number of sensors used, level of measurement noise, accuracy of structural models, and signal processing techniques. In this thesis we study dynamics of structures with damage and then derive and experimentally verify new model-independent structural damage detection methods that can locate small damage to structures. To find sensitive damage detection parameters we develop a higher-order beam element that enforces the continuity of displacements, slopes, bending moments, and shear forces at all nodes, and a higher-order rectangular plate element that enforces the continuity of displacements, slopes, and bending and twisting moments at all nodes. These two elements are used to study the dynamics of beams and plates. Results show that high-order spatial derivatives of high-frequency modes are important sensitive parameters that can locate small structural damage. Unfortunately the most powerful and popular structural modeling technique, the finite element method, is not accurate in predicting high-frequency responses. Hence, a model-independent method using dynamic responses obtained from high density measurements is concluded to be the best approach. To increase measurement density and reduce noise a Polytec PI PSV-200 scanning laser vibrometer is used to provide non-contact, dense, and accurate measurements of structural vibration velocities. To avoid the use of structural models and to extract sensitive detection parameters from experimental data, a brand-new structural damage detection method named BED (Boundary-Effect Detection) is developed for pinpointing damage locations using Operational

Analysis of warping deformation modes using higher order ANCF beam element

Science.gov (United States)

Orzechowski, Grzegorz; Shabana, Ahmed A.

2016-02-01

Most classical beam theories assume that the beam cross section remains a rigid surface under an arbitrary loading condition. However, in the absolute nodal coordinate formulation (ANCF) continuum-based beams, this assumption can be relaxed allowing for capturing deformation modes that couple the cross-section deformation and beam bending, torsion, and/or elongation. The deformation modes captured by ANCF finite elements depend on the interpolating polynomials used. The most widely used spatial ANCF beam element employs linear approximation in the transverse direction, thereby restricting the cross section deformation and leading to locking problems. The objective of this investigation is to examine the behavior of a higher order ANCF beam element that includes quadratic interpolation in the transverse directions. This higher order element allows capturing warping and non-uniform stretching distribution. Furthermore, this higher order element allows for increasing the degree of continuity at the element interface. It is shown in this paper that the higher order ANCF beam element can be used effectively to capture warping and eliminate Poisson locking that characterizes lower order ANCF finite elements. It is also shown that increasing the degree of continuity requires a special attention in order to have acceptable results. Because higher order elements can be more computationally expensive than the lower order elements, the use of reduced integration for evaluating the stress forces and the use of explicit and implicit numerical integrations to solve the nonlinear dynamic equations of motion are investigated in this paper. It is shown that the use of some of these integration methods can be very effective in reducing the CPU time without adversely affecting the solution accuracy.

The geometry of higher-order Lagrange spaces applications to mechanics and physics

CERN Document Server

Miron, Radu

1997-01-01

This monograph is devoted to the problem of the geometrizing of Lagrangians which depend on higher-order accelerations It presents a construction of the geometry of the total space of the bundle of the accelerations of order k>=1 A geometrical study of the notion of the higher-order Lagrange space is conducted, and the old problem of prolongation of Riemannian spaces to k-osculator manifolds is solved Also, the geometrical ground for variational calculus on the integral of actions involving higher-order Lagrangians is dealt with Applications to higher-order analytical mechanics and theoretical physics are included as well Audience This volume will be of interest to scientists whose work involves differential geometry, mechanics of particles and systems, calculus of variation and optimal control, optimization, optics, electromagnetic theory, and biology

Higher-Order Spectrum in Understanding Nonlinearity in EEG Rhythms

Directory of Open Access Journals (Sweden)

Cauchy Pradhan

2012-01-01

Full Text Available The fundamental nature of the brain's electrical activities recorded as electroencephalogram (EEG remains unknown. Linear stochastic models and spectral estimates are the most common methods for the analysis of EEG because of their robustness, simplicity of interpretation, and apparent association with rhythmic behavioral patterns in nature. In this paper, we extend the use of higher-order spectrum in order to indicate the hidden characteristics of EEG signals that simply do not arise from random processes. The higher-order spectrum is an extension Fourier spectrum that uses higher moments for spectral estimates. This essentially nullifies all Gaussian random effects, therefore, can reveal non-Gaussian and nonlinear characteristics in the complex patterns of EEG time series. The paper demonstrates the distinguishing features of bispectral analysis for chaotic systems, filtered noises, and normal background EEG activity. The bispectrum analysis detects nonlinear interactions; however, it does not quantify the coupling strength. The squared bicoherence in the nonredundant region has been estimated to demonstrate nonlinear coupling. The bicoherence values are minimal for white Gaussian noises (WGNs and filtered noises. Higher bicoherence values in chaotic time series and normal background EEG activities are indicative of nonlinear coupling in these systems. The paper shows utility of bispectral methods as an analytical tool in understanding neural process underlying human EEG patterns.

Higher-order neural network software for distortion invariant object recognition

Science.gov (United States)

Reid, Max B.; Spirkovska, Lilly

1991-01-01

The state-of-the-art in pattern recognition for such applications as automatic target recognition and industrial robotic vision relies on digital image processing. We present a higher-order neural network model and software which performs the complete feature extraction-pattern classification paradigm required for automatic pattern recognition. Using a third-order neural network, we demonstrate complete, 100 percent accurate invariance to distortions of scale, position, and in-plate rotation. In a higher-order neural network, feature extraction is built into the network, and does not have to be learned. Only the relatively simple classification step must be learned. This is key to achieving very rapid training. The training set is much smaller than with standard neural network software because the higher-order network only has to be shown one view of each object to be learned, not every possible view. The software and graphical user interface run on any Sun workstation. Results of the use of the neural software in autonomous robotic vision systems are presented. Such a system could have extensive application in robotic manufacturing.

Shear behaviour of reinforced phyllite concrete beams

International Nuclear Information System (INIS)

Adom-Asamoah, Mark; Owusu Afrifa, Russell

2013-01-01

Highlights: ► Phyllite concrete beams often exhibited shear with anchorage bond failure. ► Different shear design provisions for reinforced phyllite beams are compared. ► Predicted shear capacity of phyllite beams must be modified by a reduction factor. -- Abstract: The shear behaviour of concrete beams made from phyllite aggregates subjected to monotonic and cyclic loading is reported. First diagonal shear crack load of beams with and without shear reinforcement was between 42–58% and 42–92% of the failure loads respectively. The phyllite concrete beams without shear links had lower post-diagonal cracking shear resistance compared to corresponding phyllite beams with shear links. As a result of hysteretic energy dissipation, limited cyclic loading affected the stiffness, strength and deformation of the phyllite beams with shear reinforcement. Generally, beams with and without shear reinforcement showed anchorage bond failure in addition to the shear failure due to high stress concentration near the supports. The ACI, BS and EC codes are conservative for the prediction of phyllite concrete beams without shear reinforcement but they all overestimate the shear strength of phyllite concrete beams with shear reinforcement. It is recommended that the predicted shear capacity of phyllite beams reinforced with steel stirrups be modified by a reduction factor of 0.7 in order to specify a high enough safety factor on their ultimate strength. It is also recommended that susceptibility of phyllite concrete beams to undergo anchorage bond failure is averted in design by the provision of greater anchorage lengths than usually permitted.

Influence of Rotational Transform and Magnetic Shear on the Energy Content of TJ-II Plasmas

Energy Technology Data Exchange (ETDEWEB)

Estrada, T.; Ascasibar, E.; Castejon, F.; Jimenez, J. A.; Lopez-Bruna, D.; Pastor, I.

2002-07-01

In the magnetic configuration scans performed in TJ-II stellarator, low plasma energy content is found to be related to the presence of low order rational surfaces within the confinement region in low plasma density experiments. Plasma currents of about-1 kA (mainly bootstrap driven) can substantially increase the magnetic shear in TJ-II and under these conditions the confinement is no longer deteriorated by low order rational surfaces. Experiments with higher plasma currents (OH induced currents up to +/-10 kA) show a non-symmetric dependence on the sign of the magnetic shear. Preliminary results show a substantial improvement of the confinement in the case of negative plasma current, while minor changes are observed in the plasma energy content when positive current is induced in magnetic configurations that in vacuum exclude low order rational surfaces. (Author) 12 refs.

Influence of Rotational Transform and Magnetic Shear on the Energy Content of TJ-II Plasmas

International Nuclear Information System (INIS)

Estrada, T.; Ascasibar, E.; Castejon, F.; Jimenez, J. A.; Lopez-Bruna, D.; Pastor, I.

2002-01-01

In the magnetic configuration scans performed in TJ-II stellarator, low plasma energy content is found to be related to the presence of low order rational surfaces within the confinement region in low plasma density experiments. Plasma currents of about-1 kA (mainly bootstrap driven) can substantially increase the magnetic shear in TJ-II and under these conditions the confinement is no longer deteriorated by low order rational surfaces. Experiments with higher plasma currents (OH induced currents up to +/-10 kA) show a non-symmetric dependence on the sign of the magnetic shear. Preliminary results show a substantial improvement of the confinement in the case of negative plasma current, while minor changes are observed in the plasma energy content when positive current is induced in magnetic configurations that in vacuum exclude low order rational surfaces. (Author) 12 refs

Covariant quantization of infinite spin particle models, and higher order gauge theories

International Nuclear Information System (INIS)

Edgren, Ludde; Marnelius, Robert

2006-01-01

Further properties of a recently proposed higher order infinite spin particle model are derived. Infinitely many classically equivalent but different Hamiltonian formulations are shown to exist. This leads to a condition of uniqueness in the quantization process. A consistent covariant quantization is shown to exist. Also a recently proposed supersymmetric version for half-odd integer spins is quantized. A general algorithm to derive gauge invariances of higher order Lagrangians is given and applied to the infinite spin particle model, and to a new higher order model for a spinning particle which is proposed here, as well as to a previously given higher order rigid particle model. The latter two models are also covariantly quantized

Shear and loading in channels: Oscillatory shearing and edge currents of superconducting vortices

Science.gov (United States)

Wambaugh, J. F.; Marchesoni, F.; Nori, Franco

2003-04-01

Via computer simulations we study the motion of quantized magnetic flux-lines, or vortices, confined to a straight pin-free channel in a strong-pinning superconducting sample. We find that, when a constant current is applied across this system, a very unusual oscillatory shearing appears, in which the vortices moving at the edges of the channel periodically trail behind and then suddenly leapfrog past the vortices moving in the inner rows. For small enough driving forces, this oscillatory shearing dynamic phase is replaced by a continuous shearing phase in which the distance between initially-nearby vortices grows in time, quickly destroying the order of the lattice. An animation of this novel “oscillatory leapfrogging shear” effect of the vortex edge currents appears in http://www-personal.engin.umich.edu/˜nori/channel/

An Efficient Higher-Order Quasilinearization Method for Solving Nonlinear BVPs

Directory of Open Access Journals (Sweden)

Eman S. Alaidarous

2013-01-01

Full Text Available In this research paper, we present higher-order quasilinearization methods for the boundary value problems as well as coupled boundary value problems. The construction of higher-order convergent methods depends on a decomposition method which is different from Adomain decomposition method (Motsa and Sibanda, 2013. The reported method is very general and can be extended to desired order of convergence for highly nonlinear differential equations and also computationally superior to proposed iterative method based on Adomain decomposition because our proposed iterative scheme avoids the calculations of Adomain polynomials and achieves the same computational order of convergence as authors have claimed in Motsa and Sibanda, 2013. In order to check the validity and computational performance, the constructed iterative schemes are also successfully applied to bifurcation problems to calculate the values of critical parameters. The numerical performance is also tested for one-dimension Bratu and Frank-Kamenetzkii equations.

Non-homogeneous flow profiles in sheared bacterial suspensions

Science.gov (United States)

Samanta, Devranjan; Cheng, Xiang

Bacterial suspensions under shear exhibit interesting rheological behaviors including the remarkable ``superfluidic'' state with vanishing viscosity at low shear rates. Theoretical studies have shown that such ``superfluidic'' state is linked with non-homogeneous shear flows, which are induced by coupling between nematic order of active fluids and hydrodynamics of shear flows. However, although bulk rheology of bacterial suspensions has been experimentally studied, shear profiles within bacterial suspensions have not been explored so far. Here, we experimentally investigate the flow behaviors of E. coli suspensions under planar oscillatory shear. Using confocal microscopy and PIV, we measure velocity profiles across gap between two shear plates. We find that with increasing shear rates, high-concentration bacterial suspensions exhibit an array of non-homogeneous flow behaviors like yield-stress flows and shear banding. We show that these non-homogeneous flows are due to collective motion of bacterial suspensions. The phase diagram of sheared bacterial suspensions is systematically mapped as functions of shear rates an bacterial concentrations. Our experiments provide new insights into rheology of bacterial suspensions and shed light on shear induced dynamics of active fluids. Chemical Engineering and Material Science department.

A Linear-Elasticity Solver for Higher-Order Space-Time Mesh Deformation

Science.gov (United States)

Diosady, Laslo T.; Murman, Scott M.

2018-01-01

A linear-elasticity approach is presented for the generation of meshes appropriate for a higher-order space-time discontinuous finite-element method. The equations of linear-elasticity are discretized using a higher-order, spatially-continuous, finite-element method. Given an initial finite-element mesh, and a specified boundary displacement, we solve for the mesh displacements to obtain a higher-order curvilinear mesh. Alternatively, for moving-domain problems we use the linear-elasticity approach to solve for a temporally discontinuous mesh velocity on each time-slab and recover a continuous mesh deformation by integrating the velocity. The applicability of this methodology is presented for several benchmark test cases.

Higher-order-mode damper as beam-position monitors; Higher-Order-Mode Daempfer als Stahllagemonitore

Energy Technology Data Exchange (ETDEWEB)

Peschke, C.

2006-03-15

In the framework of this thesis a beam-position monitor was developed, which can only because of the signals from the HOM dampers of a linear-accelerator structure determine the beam position with high accuracy. For the unique determination of the beam position in the plane a procedure was developed, which uses the amplitudes and the start-phase difference between a dipole mode and a higher monopole mode. In order tocheck the suitability of the present SBLC-HOM damper as beam position monitor three-dimensional numerical field calculations in the frequency and time range and measurements on the damper cell were performed. For the measurements without beam a beam simulator was constructed, which allows computer-driven measurements with variable depositions of the simulated beam with a resolution of 1.23 {mu}m. Because the complete 6 m long, 180-cell accelerator structure was not available for measurements and could also with the available computers not be three-dimensionally simulated simulated, a one-dimensional equivalent-circuit based model of the multi-cell was studied. The equivalent circuits with 879 concentrated components regards the detuning from cell to cell, the cell losses, the damper losses, and the beam excitation in dependence on the deposition. the measurements and simulations let a resolution of the ready beam-position monitor on the 180-cell in the order of magnitude of 1-10 {mu}m and a relative accuracy smaller 6.2% be expected.

Second-harmonic generation in shear wave beams with different polarizations

Science.gov (United States)

Spratt, Kyle S.; Ilinskii, Yurii A.; Zabolotskaya, Evgenia A.; Hamilton, Mark F.

2015-10-01

A coupled pair of nonlinear parabolic equations was derived by Zabolotskaya [1] that model the transverse components of the particle motion in a collimated shear wave beam propagating in an isotropic elastic solid. Like the KZK equation, the parabolic equation for shear wave beams accounts consistently for the leading order effects of diffraction, viscosity and nonlinearity. The nonlinearity includes a cubic nonlinear term that is equivalent to that present in plane shear waves, as well as a quadratic nonlinear term that is unique to diffracting beams. The work by Wochner et al. [2] considered shear wave beams with translational polarizations (linear, circular and elliptical), wherein second-order nonlinear effects vanish and the leading order nonlinear effect is third-harmonic generation by the cubic nonlinearity. The purpose of the current work is to investigate the quadratic nonlinear term present in the parabolic equation for shear wave beams by considering second-harmonic generation in Gaussian beams as a second-order nonlinear effect using standard perturbation theory. In order for second-order nonlinear effects to be present, a broader class of source polarizations must be considered that includes not only the familiar translational polarizations, but also polarizations accounting for stretching, shearing and rotation of the source plane. It is found that the polarization of the second harmonic generated by the quadratic nonlinearity is not necessarily the same as the polarization of the source-frequency beam, and we are able to derive a general analytic solution for second-harmonic generation from a Gaussian source condition that gives explicitly the relationship between the polarization of the source-frequency beam and the polarization of the second harmonic.

Second-harmonic generation in shear wave beams with different polarizations

Energy Technology Data Exchange (ETDEWEB)

Spratt, Kyle S., E-mail: sprattkyle@gmail.com; Ilinskii, Yurii A.; Zabolotskaya, Evgenia A.; Hamilton, Mark F. [Applied Research Laboratories, The University of Texas at Austin, P. O. Box 8029, Austin, Texas 78713–8029, US (United States)

2015-10-28

A coupled pair of nonlinear parabolic equations was derived by Zabolotskaya [1] that model the transverse components of the particle motion in a collimated shear wave beam propagating in an isotropic elastic solid. Like the KZK equation, the parabolic equation for shear wave beams accounts consistently for the leading order effects of diffraction, viscosity and nonlinearity. The nonlinearity includes a cubic nonlinear term that is equivalent to that present in plane shear waves, as well as a quadratic nonlinear term that is unique to diffracting beams. The work by Wochner et al. [2] considered shear wave beams with translational polarizations (linear, circular and elliptical), wherein second-order nonlinear effects vanish and the leading order nonlinear effect is third-harmonic generation by the cubic nonlinearity. The purpose of the current work is to investigate the quadratic nonlinear term present in the parabolic equation for shear wave beams by considering second-harmonic generation in Gaussian beams as a second-order nonlinear effect using standard perturbation theory. In order for second-order nonlinear effects to be present, a broader class of source polarizations must be considered that includes not only the familiar translational polarizations, but also polarizations accounting for stretching, shearing and rotation of the source plane. It is found that the polarization of the second harmonic generated by the quadratic nonlinearity is not necessarily the same as the polarization of the source-frequency beam, and we are able to derive a general analytic solution for second-harmonic generation from a Gaussian source condition that gives explicitly the relationship between the polarization of the source-frequency beam and the polarization of the second harmonic.

Second-harmonic generation in shear wave beams with different polarizations

International Nuclear Information System (INIS)

Spratt, Kyle S.; Ilinskii, Yurii A.; Zabolotskaya, Evgenia A.; Hamilton, Mark F.

2015-01-01

A coupled pair of nonlinear parabolic equations was derived by Zabolotskaya [1] that model the transverse components of the particle motion in a collimated shear wave beam propagating in an isotropic elastic solid. Like the KZK equation, the parabolic equation for shear wave beams accounts consistently for the leading order effects of diffraction, viscosity and nonlinearity. The nonlinearity includes a cubic nonlinear term that is equivalent to that present in plane shear waves, as well as a quadratic nonlinear term that is unique to diffracting beams. The work by Wochner et al. [2] considered shear wave beams with translational polarizations (linear, circular and elliptical), wherein second-order nonlinear effects vanish and the leading order nonlinear effect is third-harmonic generation by the cubic nonlinearity. The purpose of the current work is to investigate the quadratic nonlinear term present in the parabolic equation for shear wave beams by considering second-harmonic generation in Gaussian beams as a second-order nonlinear effect using standard perturbation theory. In order for second-order nonlinear effects to be present, a broader class of source polarizations must be considered that includes not only the familiar translational polarizations, but also polarizations accounting for stretching, shearing and rotation of the source plane. It is found that the polarization of the second harmonic generated by the quadratic nonlinearity is not necessarily the same as the polarization of the source-frequency beam, and we are able to derive a general analytic solution for second-harmonic generation from a Gaussian source condition that gives explicitly the relationship between the polarization of the source-frequency beam and the polarization of the second harmonic

Evaluation of shear bond strength and shear stress on zirconia reinforced lithium silicate and high translucency zirconia.

Directory of Open Access Journals (Sweden)

Amanda Maria de Oliveira Dal Piva

2018-01-01

Full Text Available This study evaluated the shear stress distribution on the adhesive interface and the bond strength between resin cement and two ceramics. For finite element analysis (FEA, a tridimensional model was made using computer-aided design software. This model consisted of a ceramic slice (10x10x2mm partially embedded on acrylic resin with a resin cement cylinder (Ø=3.4 mm and h=3mm cemented on the external surface. Results of maximum principal stress and maximum principal shear were obtained to evaluate the stress generated on the ceramic and the cylinder surfaces. In order to reproduce the in vitro test, similar samples to the computational model were manufactured according to ceramic material (Zirconia reinforced lithium silicate - ZLS and high translucency Zirconia - YZHT, (N=48, n=12. Half of the specimens were submitted to shear bond test after 24h using a universal testing machine (0.5 mm/min, 50kgf until fracture. The other half was stored (a (180 days, water, 37ºC prior to the test. Bond strength was calculated in MPa and submitted to analysis of variance. The results showed that ceramic material influenced bond strength mean values (p=0.002, while aging did not: YZHT (19.80±6.44a, YZHTa (17.95±7.21a, ZLS (11.88±5.40b, ZLSa (11.76±3.32b. FEA results showed tensile and shear stress on ceramic and cylinder surfaces with more intensity on their periphery. Although the stress distribution was similar for both conditions, YZHT showed higher bond strength values; however, both materials seemed to promote durable bond strength.

Higher-Order Hierarchical Legendre Basis Functions in Applications

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Jørgensen, Erik; Meincke, Peter

2007-01-01

The higher-order hierarchical Legendre basis functions have been developed for effective solution of integral equations with the method of moments. They are derived from orthogonal Legendre polynomials modified to enforce normal continuity between neighboring mesh elements, while preserving a high...

Development of a Skewed Pipe Shear Connector for Precast Concrete Structures.

Science.gov (United States)

Kim, Sang-Hyo; Choi, Jae-Gu; Park, Sejun; Lee, Hyunmin; Heo, And Won-Ho

2017-05-13

Joint connection methods, such as shear key and loop bar, improve the structural performance of precast concrete structures; consequently, there is usually decreased workability or constructional efficiency. This paper proposes a high-efficiency skewed pipe shear connector. To resist shear and pull-out forces, the proposed connectors are placed diagonally between precast concrete segments and a cast-in-place concrete joint part on a girder. Design variables (such as the pipe diameter, length, and insertion angle) have been examined to investigate the connection performance of the proposed connector. The results of our testing indicate that the skewed pipe shear connectors have 50% higher ductility and a 15% higher ratio of maximum load to yield strength as compared to the corresponding parameters of the loop bar. Finite element analysis was used for validation. The resulting validation indicates that, compared to the loop bar, the skewed pipe shear connector has a higher ultimate shear and pull-out resistance. These results indicate that the skewed pipe shear connector demonstrates more idealized behavior than the loop bar in precast concrete structures.

Extremely high wall-shear stress events in a turbulent boundary layer

Science.gov (United States)

Pan, Chong; Kwon, Yongseok

2018-04-01

The present work studies the fluctuating characteristics of the streamwise wall-shear stress in a DNS of a turbulent boundary layer at Re τ =1500 from a structural view. The two-dimensional field of the fluctuating friction velocity u‧ τ (x,z) is decomposed into the large- and small-scale components via a recently proposed scale separation algorithm, Quasi-bivariate Variational Mode Decomposition (QB-VMD). Both components are found to be dominated by streak-like structures, which can be regarded as the wall signature of the inner-layer streaks and the outer-layer LSMs, respectively. Extreme positive/negative wall-shear stress fluctuation events are detected in the large-scale component. The former’s occurrence frequency is nearly one order of magnitude higher than the latter; therefore, they contribute a significant portion of the long tail of the wall-shear stress distribution. Both two-point correlations and conditional averages show that these extreme positive wall-shear stress events are embedded in the large-scale positive u‧ τ streaks. They seem to be formed by near-wall ‘splatting’ process, which are related to strong finger-like sweeping (Q4) events originated from the outer-layer positive LSMs.

Higher order BLG supersymmetry transformations from 10-dimensional super Yang Mills

Energy Technology Data Exchange (ETDEWEB)

Hall, John [Alumnus of Physics Department, Imperial College,South Kensington, London, SW7 2AZ (United Kingdom); Low, Andrew [Physics Department, Wimbledon High School,Mansel Road, London, SW19 4AB (United Kingdom)

2014-06-26

We study a Simple Route for constructing the higher order Bagger-Lambert-Gustavsson theory - both supersymmetry transformations and Lagrangian - starting from knowledge of only the 10-dimensional Super Yang Mills Fermion Supersymmetry transformation. We are able to uniquely determine the four-derivative order corrected supersymmetry transformations, to lowest non-trivial order in Fermions, for the most general three-algebra theory. For the special case of Euclidean three-algbera, we reproduce the result presented in arXiv:1207.1208, with significantly less labour. In addition, we apply our method to calculate the quadratic fermion terms in the higher order BLG fermion supersymmetry transformation.

Hamiltonian formulation of theory with higher order derivatives

International Nuclear Information System (INIS)

Gitman, D.M.; Lyakhovich, S.L.; Tyutin, I.V.

1983-01-01

A method of ''hamiltonization'' of a special theory with higher order derivatives is described. In a nonspecial case the result coincides with the known Ostrogradsky formulation. It is shown that in the nonspecial theory the lagrange equations of motion are reduced to the normal form

Higher order polynomial expansion nodal method for hexagonal core neutronics analysis

International Nuclear Information System (INIS)

Jin, Young Cho; Chang, Hyo Kim

1998-01-01

A higher-order polynomial expansion nodal(PEN) method is newly formulated as a means to improve the accuracy of the conventional PEN method solutions to multi-group diffusion equations in hexagonal core geometry. The new method is applied to solving various hexagonal core neutronics benchmark problems. The computational accuracy of the higher order PEN method is then compared with that of the conventional PEN method, the analytic function expansion nodal (AFEN) method, and the ANC-H method. It is demonstrated that the higher order PEN method improves the accuracy of the conventional PEN method and that it compares very well with the other nodal methods like the AFEN and ANC-H methods in accuracy

Coaxial higher-order mode damper employing a high-pass filter

International Nuclear Information System (INIS)

Kang, Y.W.; Jiang, X.

1997-01-01

Two different types of coaxial higher-order mode (HOM) dampers have been investigated for the Advanced Photon Source (APS) storage ring cavities: e-probe dampers and h-loop dampers. Realization of the h-loop dampers has been difficult because the loop antenna couples not only to the HOMs but also to the accelerating mode and results in loss of Q at the fundamental frequency. Previously, a first-order fundamental rejection filter was tested with unsatisfactory rejection characteristics. This problem can be overcome by using a higher-order high-pass filter between the loop and the matched load. Prototype dampers have been fabricated and tested in a storage ring single-cell cavity and the damping characteristic was analyzed

A New Hyperbolic Shear Deformation Theory for Bending Analysis of Functionally Graded Plates

Directory of Open Access Journals (Sweden)

Tahar Hassaine Daouadji

2012-01-01

Full Text Available Theoretical formulation, Navier’s solutions of rectangular plates based on a new higher order shear deformation model are presented for the static response of functionally graded plates. This theory enforces traction-free boundary conditions at plate surfaces. Shear correction factors are not required because a correct representation of transverse shearing strain is given. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The mechanical properties of the plate are assumed to vary continuously in the thickness direction by a simple power-law distribution in terms of the volume fractions of the constituents. Numerical illustrations concern flexural behavior of FG plates with metal-ceramic composition. Parametric studies are performed for varying ceramic volume fraction, volume fractions profiles, aspect ratios, and length to thickness ratios. Results are verified with available results in the literature. It can be concluded that the proposed theory is accurate and simple in solving the static bending behavior of functionally graded plates.

Ultra-compact Higher-Order-Mode Pass Filter in a Silicon Waveguide

DEFF Research Database (Denmark)

Guan, Xiaowei; Frandsen, Lars Hagedorn; Ding, Yunhong

2015-01-01

An 3.7 μm long higher-order-mode pass filter with an extinction ratio larger than 20 dB is demonstrated in a 1D corrugated silicon multimode waveguide......An 3.7 μm long higher-order-mode pass filter with an extinction ratio larger than 20 dB is demonstrated in a 1D corrugated silicon multimode waveguide...

Analysis of Scattering by Inhomogeneous Dielectric Objects Using Higher-Order Hierarchical MoM

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Jørgensen, Erik; Meincke, Peter

2003-01-01

An efficient technique for the analysis of electromagnetic scattering by arbitrary shaped inhomogeneous dielectric objects is presented. The technique is based on a higher-order method of moments (MoM) solution of the volume integral equation. This higher-order MoM solution comprises recently...... that the condition number of the resulting MoM matrix is reduced by several orders of magnitude in comparison to existing higher-order hierarchical basis functions and, consequently, an iterative solver can be applied even for high expansion orders. Numerical results demonstrate excellent agreement...

Behavior of Tilted Angle Shear Connectors

Science.gov (United States)

Khorramian, Koosha; Maleki, Shervin; Shariati, Mahdi; Ramli Sulong, N. H.

2015-01-01

According to recent researches, angle shear connectors are appropriate to transfer longitudinal shear forces across the steel-concrete interface. Angle steel profile has been used in different positions as L-shaped or C-shaped shear connectors. The application of angle shear connectors in tilted positions is of interest in this study. This study investigates the behaviour of tilted-shaped angle shear connectors under monotonic loading using experimental push out tests. Eight push-out specimens are tested to investigate the effects of different angle parameters on the ultimate load capacity of connectors. Two different tilted angles of 112.5 and 135 degrees between the angle leg and steel beam are considered. In addition, angle sizes and lengths are varied. Two different failure modes were observed consisting of concrete crushing-splitting and connector fracture. By increasing the size of connector, the maximum load increased for most cases. In general, the 135 degrees tilted angle shear connectors have a higher strength and stiffness than the 112.5 degrees type. PMID:26642193

Behavior of Tilted Angle Shear Connectors.

Directory of Open Access Journals (Sweden)

Koosha Khorramian

Full Text Available According to recent researches, angle shear connectors are appropriate to transfer longitudinal shear forces across the steel-concrete interface. Angle steel profile has been used in different positions as L-shaped or C-shaped shear connectors. The application of angle shear connectors in tilted positions is of interest in this study. This study investigates the behaviour of tilted-shaped angle shear connectors under monotonic loading using experimental push out tests. Eight push-out specimens are tested to investigate the effects of different angle parameters on the ultimate load capacity of connectors. Two different tilted angles of 112.5 and 135 degrees between the angle leg and steel beam are considered. In addition, angle sizes and lengths are varied. Two different failure modes were observed consisting of concrete crushing-splitting and connector fracture. By increasing the size of connector, the maximum load increased for most cases. In general, the 135 degrees tilted angle shear connectors have a higher strength and stiffness than the 112.5 degrees type.

A simplified parsimonious higher order multivariate Markov chain model

Science.gov (United States)

Wang, Chao; Yang, Chuan-sheng

2017-09-01

In this paper, a simplified parsimonious higher-order multivariate Markov chain model (SPHOMMCM) is presented. Moreover, parameter estimation method of TPHOMMCM is give. Numerical experiments shows the effectiveness of TPHOMMCM.

Focusing of Shear Shock Waves

Science.gov (United States)

Giammarinaro, Bruno; Espíndola, David; Coulouvrat, François; Pinton, Gianmarco

2018-01-01

Focusing is a ubiquitous way to transform waves. Recently, a new type of shock wave has been observed experimentally with high-frame-rate ultrasound: shear shock waves in soft solids. These strongly nonlinear waves are characterized by a high Mach number, because the shear wave velocity is much slower, by 3 orders of magnitude, than the longitudinal wave velocity. Furthermore, these waves have a unique cubic nonlinearity which generates only odd harmonics. Unlike longitudinal waves for which only compressional shocks are possible, shear waves exhibit cubic nonlinearities which can generate positive and negative shocks. Here we present the experimental observation of shear shock wave focusing, generated by the vertical motion of a solid cylinder section embedded in a soft gelatin-graphite phantom to induce linearly vertically polarized motion. Raw ultrasound data from high-frame-rate (7692 images per second) acquisitions in combination with algorithms that are tuned to detect small displacements (approximately 1 μ m ) are used to generate quantitative movies of gel motion. The features of shear shock wave focusing are analyzed by comparing experimental observations with numerical simulations of a retarded-time elastodynamic equation with cubic nonlinearities and empirical attenuation laws for soft solids.

Shear machines

International Nuclear Information System (INIS)

Astill, M.; Sunderland, A.; Waine, M.G.

1980-01-01

A shear machine for irradiated nuclear fuel elements has a replaceable shear assembly comprising a fuel element support block, a shear blade support and a clamp assembly which hold the fuel element to be sheared in contact with the support block. A first clamp member contacts the fuel element remote from the shear blade and a second clamp member contacts the fuel element adjacent the shear blade and is advanced towards the support block during shearing to compensate for any compression of the fuel element caused by the shear blade (U.K.)

Higher Order Differential Attack on 6-Round MISTY1

Science.gov (United States)

Tsunoo, Yukiyasu; Saito, Teruo; Nakashima, Hiroki; Shigeri, Maki

MISTY1 is a 64-bit block cipher that has provable security against differential and linear cryptanalysis. MISTY1 is one of the algorithms selected in the European NESSIE project, and it has been recommended for Japanese e-Government ciphers by the CRYPTREC project. This paper reports a previously unknown higher order differential characteristic of 4-round MISTY1 with the FL functions. It also shows that a higher order differential attack that utilizes this newly discovered characteristic is successful against 6-round MISTY1 with the FL functions. This attack can recover a partial subkey with a data complexity of 253.7 and a computational complexity of 264.4, which is better than any previous cryptanalysis of MISTY1.

Higher-order automatic differentiation of mathematical functions

Science.gov (United States)

Charpentier, Isabelle; Dal Cappello, Claude

2015-04-01

Functions of mathematical physics such as the Bessel functions, the Chebyshev polynomials, the Gauss hypergeometric function and so forth, have practical applications in many scientific domains. On the one hand, differentiation formulas provided in reference books apply to real or complex variables. These do not account for the chain rule. On the other hand, based on the chain rule, the automatic differentiation has become a natural tool in numerical modeling. Nevertheless automatic differentiation tools do not deal with the numerous mathematical functions. This paper describes formulas and provides codes for the higher-order automatic differentiation of mathematical functions. The first method is based on Faà di Bruno's formula that generalizes the chain rule. The second one makes use of the second order differential equation they satisfy. Both methods are exemplified with the aforementioned functions.

Computer-Mediated Assessment of Higher-Order Thinking Development

Science.gov (United States)

Tilchin, Oleg; Raiyn, Jamal

2015-01-01

Solving complicated problems in a contemporary knowledge-based society requires higher-order thinking (HOT). The most productive way to encourage development of HOT in students is through use of the Problem-based Learning (PBL) model. This model organizes learning by solving corresponding problems relative to study courses. Students are directed…

Catenary Action in Rebars Crossing a Casting Joint Loaded in Shear

DEFF Research Database (Denmark)

Sørensen, Jesper Harrild; Hoang, Linh Cao; Olesen, John Forbes

2016-01-01

Reinforcement crossing a casting joint loaded in shear exhibits catenary action as the shear displacement increases. The load carrying capacity of such a joint is in practice often calculated by use of empirical methods to account for shear friction effects or by a first order plastic analysis...... if dowel action is included. The strength increase/reserve due to catenary action in the rebars is often neglected; however in some cases it may be necessary to utilize the effect in order to ensure overall structural robustness. This paper presents results of a study, where the increased shear capacity...... and theory is found when reasonable material properties are assumed....

Neurodevelopmental outcomes of triplets or higher-order extremely low birth weight infants.

Science.gov (United States)

Wadhawan, Rajan; Oh, William; Vohr, Betty R; Wrage, Lisa; Das, Abhik; Bell, Edward F; Laptook, Abbot R; Shankaran, Seetha; Stoll, Barbara J; Walsh, Michele C; Higgins, Rosemary D

2011-03-01

Extremely low birth weight twins have a higher rate of death or neurodevelopmental impairment than singletons. Higher-order extremely low birth weight multiple births may have an even higher rate of death or neurodevelopmental impairment. Extremely low birth weight (birth weight 401-1000 g) multiple births born in participating centers of the Neonatal Research Network between 1996 and 2005 were assessed for death or neurodevelopmental impairment at 18 to 22 months' corrected age. Neurodevelopmental impairment was defined by the presence of 1 or more of the following: moderate to severe cerebral palsy; mental developmental index score or psychomotor developmental index score less than 70; severe bilateral deafness; or blindness. Infants who died within 12 hours of birth were excluded. Maternal and infant demographic and clinical variables were compared among singleton, twin, and triplet or higher-order infants. Logistic regression analysis was performed to establish the association between singletons, twins, and triplet or higher-order multiples and death or neurodevelopmental impairment, controlling for confounding variables that may affect death or neurodevelopmental impairment. Our cohort consisted of 8296 singleton, 2164 twin, and 521 triplet or higher-order infants. The risk of death or neurodevelopmental impairment was increased in triplets or higher-order multiples when compared with singletons (adjusted odds ratio: 1.7 [95% confidence interval: 1.29-2.24]), and there was a trend toward an increased risk when compared with twins (adjusted odds ratio: 1.27 [95% confidence: 0.95-1.71]). Triplet or higher-order births are associated with an increased risk of death or neurodevelopmental impairment at 18 to 22 months' corrected age when compared with extremely low birth weight singleton infants, and there was a trend toward an increased risk when compared with twins.

Flow rate dependency of critical wall shear stress in a radial-flow cell

DEFF Research Database (Denmark)

Detry, J.G.; Jensen, Bo Boye Busk; Sindic, M.

2009-01-01

In the present work, a radial-flow cell was used to study the removal of starch particle aggregates from several solid substrates (glass, stainless steel, polystyrene and PTFE) in order to determine the critical wall shear stress value for each case. The particle aggregates were formed by aspersion...... of a water or ethanol suspension of starch granules on the surfaces. Depending on the substrate and on the suspending liquid, the aggregates differed in size and shape. Aggregate removal was studied at two flow rates. At the lower flow rate (Re-inlet = 955), the values of critical wall shear stress...... for the different surfaces suggested that capillary forces were, for all of them, playing an important role in aggregate adhesion since aqueous based aggregates were always more difficult to remove. At the higher flow rate (Re-inlet = 2016) the critical wall shear stress increased as a result of the change...

Analysis of Buried Dielectric Objects Using Higher-Order MoM for Volume Integral Equations

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Meincke, Peter; Breinbjerg, Olav

2004-01-01

A higher-order method of moments (MoM) is applied to solve a volume integral equation for dielectric objects in layered media. In comparison to low-order methods, the higher-order MoM, which is based on higher-order hierarchical Legendre vector basis functions and curvilinear hexahedral elements,...

Effect of particle-particle shearing on the bioleaching of sulfide minerals.

Science.gov (United States)

Chong, N; Karamanev, D G; Margaritis, A

2002-11-05

The biological leaching of sulfide minerals, used for the production of gold, copper, zinc, cobalt, and other metals, is very often carried out in slurry bioreactors, where the shearing between sulfide particles is intensive. In order to be able to improve the efficiency of the bioleaching, it is of significant importance to know the effect of particle shearing on the rate of leaching. The recently proposed concept of ore immobilization allowed us to study the effect of particle shearing on the rate of sulfide (pyrite) leaching by Thiobacillus ferrooxidans. Using this concept, we designed two very similar bioreactors, the main difference between which was the presence and absence of particle-particle shearing. It was shown that when the oxygen mass transfer was not the rate-limiting step, the rate of bioleaching in the frictionless bioreactor was 2.5 times higher than that in a bioreactor with particle friction (shearing). The concentration of free suspended cells in the frictionless bioreactor was by orders of magnitude lower than that in the frictional bioreactor, which showed that particle friction strongly reduces the microbial attachment to sulfide surface, which, in turn, reduces the rate of bioleaching. Surprisingly, it was found that formation of a layer of insoluble iron salts on the surface of sulfide particles is much slower under shearless conditions than in the presence of particle-particle shearing. This was explained by the effect of particle friction on liquid-solid mass transfer rate. The results of this study show that reduction of the particle friction during bioleaching of sulfide minerals can bring important advantages not only by increasing significantly the bioleaching rate, but also by increasing the rate of gas-liquid oxygen mass transfer, reducing the formation of iron precipitates and reducing the energy consumption. One of the efficient methods for reduction of particle friction is ore immobilization in a porous matrix. Copyright 2002

Confinement in W7-AS and the role of radial electric field and magnetic shear

International Nuclear Information System (INIS)

Brakel, R.; Anton, M.; Baldzuhn, J.; Burhenn, R.; Erckmann, V.; Fiedler, S.; Geiger, J.; Hartfuss, H.J.; Heinrich, O.; Hirsch, M.; Jaenicke, R.; Kick, M.; Kuehner, G.; Maassberg, H.; Stroth, U.; Wagner, F.; Weller, A.

1997-01-01

Improved neoclassical electron confinement in the centre of low-density ECRH plasmas has been observed in the presence of a strong positive radial electric field, which resembles the electron root solution of the neoclassical ambipolarity condition but is obviously driven by the loss of ECRH-generated suprathermal electrons. At higher densities and with NBI heating, a high confinement regime substantially above the ISS95-scaling and different from the H-mode is established with a strongly sheared negative radial electric field at the boundary. The application of plasma-current induced magnetic shear reveals that confinement in W7-AS is essentially determined by perturbations at high-order rational surfaces. For optimum confinement, these resonances have either to be avoided in the boundary region or magnetic shear must be sufficiently large. Independent of its sign, magnetic shear can reduce electron energy transport which is enhanced in the presence of such resonances to the neoclassical level. (author)

Effect of Boundary Condition on the Shear Behaviour of Rock Joints in the Direct Shear Test

Science.gov (United States)

Bahaaddini, M.

2017-05-01

The common method for determination of the mechanical properties of the rock joints is the direct shear test. This paper aims to study the effect of boundary condition on the results of direct shear tests. Experimental studies undertaken in this research showed that the peak shear strength is mostly overestimated. This problem is more pronounced for steep asperities and under high normal stresses. Investigation of the failure mode of these samples showed that tensile cracks are generated at the boundary of sample close to the specimen holders and propagated inside the intact materials. In order to discover the reason of observed failure mechanism in experiments, the direct shear test was simulated using PFC2D. Results of numerical models showed that the gap zone size between the upper and lower specimen holders has a significant effect on the shear mechanism. For the high gap size, stresses concentrate at the vicinity of the tips of specimen holders and result in generation and propagation of tensile cracks inside the intact material. However, by reducing the gap size, stresses are concentrated on asperities, and damage of specimen at its boundary is not observed. Results of this paper show that understanding the shear mechanism of rock joints is an essential step prior to interpreting the results of direct shear tests.

A tridiagonal parsimonious higher order multivariate Markov chain model

Science.gov (United States)

Wang, Chao; Yang, Chuan-sheng

2017-09-01

In this paper, we present a tridiagonal parsimonious higher-order multivariate Markov chain model (TPHOMMCM). Moreover, estimation method of the parameters in TPHOMMCM is give. Numerical experiments illustrate the effectiveness of TPHOMMCM.

Lagrangian procedures for higher order field equations

International Nuclear Information System (INIS)

Bollini, C.G.

1987-01-01

A Lagrangian procedure for a pedagogical way is presented for the treatment of higher order field equations. The energy-momentum tensor and the conserved density current are built. In particular the case in which the derivatives appear only in the invariant D'Alembertian operator is discussed. Some examples are discussed. The fields are quantized and the corresponding Hamilonian which is shown not to be positive defructed. Rules are given to write the causal propagators. (author) [pt

Lagrangian procedures for higher order field equations

International Nuclear Information System (INIS)

Bollini, C.G.; Giambiagi, J.J.

1986-01-01

We present in a pedagogical way a Lagrangian procedure for the treatment of higher order field equations. We build the energy-momentum tensor and the conserved density current. In particular we discuss the case in which the derivatives appear only in the invariant D'Alembertian operator. We discuss some examples. We quantize the fields and construct the corresponding Hamiltonian which is shown not to be positive definite. We give the rules for the causal propagators. (Author) [pt

Enhancing Higher Order Thinking Skills through Clinical Simulation

Science.gov (United States)

Varutharaju, Elengovan; Ratnavadivel, Nagendralingan

2014-01-01

Purpose: The study aimed to explore, describe and analyse the design and implementation of clinical simulation as a pedagogical tool in bridging the deficiency of higher order thinking skills among para-medical students, and to make recommendations on incorporating clinical simulation as a pedagogical tool to enhance thinking skills and align the…

SHARP: A Spatially Higher-order, Relativistic Particle-in-cell Code

Energy Technology Data Exchange (ETDEWEB)

Shalaby, Mohamad; Broderick, Avery E. [Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); Chang, Philip [Department of Physics, University of Wisconsin-Milwaukee, 1900 E. Kenwood Boulevard, Milwaukee, WI 53211 (United States); Pfrommer, Christoph [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Lamberts, Astrid [Theoretical Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Puchwein, Ewald, E-mail: mshalaby@live.ca [Institute of Astronomy and Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom)

2017-05-20

Numerical heating in particle-in-cell (PIC) codes currently precludes the accurate simulation of cold, relativistic plasma over long periods, severely limiting their applications in astrophysical environments. We present a spatially higher-order accurate relativistic PIC algorithm in one spatial dimension, which conserves charge and momentum exactly. We utilize the smoothness implied by the usage of higher-order interpolation functions to achieve a spatially higher-order accurate algorithm (up to the fifth order). We validate our algorithm against several test problems—thermal stability of stationary plasma, stability of linear plasma waves, and two-stream instability in the relativistic and non-relativistic regimes. Comparing our simulations to exact solutions of the dispersion relations, we demonstrate that SHARP can quantitatively reproduce important kinetic features of the linear regime. Our simulations have a superior ability to control energy non-conservation and avoid numerical heating in comparison to common second-order schemes. We provide a natural definition for convergence of a general PIC algorithm: the complement of physical modes captured by the simulation, i.e., those that lie above the Poisson noise, must grow commensurately with the resolution. This implies that it is necessary to simultaneously increase the number of particles per cell and decrease the cell size. We demonstrate that traditional ways for testing for convergence fail, leading to plateauing of the energy error. This new PIC code enables us to faithfully study the long-term evolution of plasma problems that require absolute control of the energy and momentum conservation.

The influence of high shear mixing on ternary dry powder inhaler formulations.

Science.gov (United States)

Hertel, Mats; Schwarz, Eugen; Kobler, Mirjam; Hauptstein, Sabine; Steckel, Hartwig; Scherließ, Regina

2017-12-20

The blending process is a key step in the production of dry powder inhaler formulations, but only little is known about the influence of process parameters. This is especially true for high shear blending of ternary formulations. For this reason, this study aims to investigate the influence of high shear mixing process parameters (mixing time and rotation speed) on the fine particle fraction (FPF) of ternary mixtures when using budesonide as model drug, two different carrier materials and two different mixing orders. Prolonged mixing time and higher rotation speeds led to lower FPFs, possibly due to higher press-on forces acting on the active pharmaceutical ingredients (API). In addition, a clear correlation between the energy consumption of the blender (the energy input into the blend) and the reduction of the FPF could be shown. Furthermore blending the carrier and the fines before adding the API was also found to be favorable. Copyright © 2017 Elsevier B.V. All rights reserved.

Higher order aberrations in amblyopic children and their role in refractory amblyopia

Directory of Open Access Journals (Sweden)

Arnaldo Dias-Santos

2014-12-01

Full Text Available Objective: Some studies have hypothesized that an unfavourable higher order aberrometric profile could act as an amblyogenic mechanism and may be responsible for some amblyopic cases that are refractory to conventional treatment or cases of “idiopathic” amblyopia. This study compared the aberrometric profile in amblyopic children to that of children with normal visual development and compared the aberrometric profile in corrected amblyopic eyes and refractory amblyopic eyes with that of healthy eyes. Methods: Cross-sectional study with three groups of children – the CA group (22 eyes of 11 children with unilateral corrected amblyopia, the RA group (24 eyes of 13 children with unilateral refractory amblyopia and the C group (28 eyes of 14 children with normal visual development. Higher order aberrations were evaluated using an OPD-Scan III (NIDEK. Comparisons of the aberrometric profile were made between these groups as well as between the amblyopic and healthy eyes within the CA and RA groups. Results: Higher order aberrations with greater impact in visual quality were not significantly higher in the CA and RA groups when compared with the C group. Moreover, there were no statistically significant differences in the higher order aberrometric profile between the amblyopic and healthy eyes within the CA and RA groups. Conclusions: Contrary to lower order aberrations (e.g., myopia, hyperopia, primary astigmatism, higher order aberrations do not seem to be involved in the etiopathogenesis of amblyopia. Therefore, these are likely not the cause of most cases of refractory amblyopia.

Near integrability of kink lattice with higher order interactions

Science.gov (United States)

Jiang, Yun-Guo; Liu, Jia-Zhen; He, Song

2017-11-01

We make use of Manton’s analytical method to investigate the force between kinks and anti-kinks at large distances in 1+1 dimensional field theory. The related potential has infinite order corrections of exponential pattern, and the coefficients for each order are determined. These coefficients can also be obtained by solving the equation of the fluctuations around the vacuum. At the lowest order, the kink lattice represents the Toda lattice. With higher order correction terms, the kink lattice can represent one kind of generic Toda lattice. With only two sites, the kink lattice is classically integrable. If the number of sites of the lattice is larger than two, the kink lattice is not integrable but is a near integrable system. We make use of Flaschka’s variables to study the Lax pair of the kink lattice. These Flaschka’s variables have interesting algebraic relations and non-integrability can be manifested. We also discuss the higher Hamiltonians for the deformed open Toda lattice, which has a similar result to the ordinary deformed Toda. Supported by Shandong Provincial Natural Science Foundation (ZR2014AQ007), National Natural Science Foundation of China (11403015, U1531105), S. He is supported by Max-Planck fellowship in Germany and National Natural Science Foundation of China (11305235)

Building unbiased estimators from non-Gaussian likelihoods with application to shear estimation

International Nuclear Information System (INIS)

Madhavacheril, Mathew S.; Sehgal, Neelima; McDonald, Patrick; Slosar, Anže

2015-01-01

We develop a general framework for generating estimators of a given quantity which are unbiased to a given order in the difference between the true value of the underlying quantity and the fiducial position in theory space around which we expand the likelihood. We apply this formalism to rederive the optimal quadratic estimator and show how the replacement of the second derivative matrix with the Fisher matrix is a generic way of creating an unbiased estimator (assuming choice of the fiducial model is independent of data). Next we apply the approach to estimation of shear lensing, closely following the work of Bernstein and Armstrong (2014). Our first order estimator reduces to their estimator in the limit of zero shear, but it also naturally allows for the case of non-constant shear and the easy calculation of correlation functions or power spectra using standard methods. Both our first-order estimator and Bernstein and Armstrong's estimator exhibit a bias which is quadratic in true shear. Our third-order estimator is, at least in the realm of the toy problem of Bernstein and Armstrong, unbiased to 0.1% in relative shear errors Δg/g for shears up to |g|=0.2

Developing Higher-Order Thinking Skills through WebQuests

Science.gov (United States)

Polly, Drew; Ausband, Leigh

2009-01-01

In this study, 32 teachers participated in a year-long professional development project related to technology integration in which they designed and implemented a WebQuest. This paper describes the extent to which higher-order thinking skills (HOTS) and levels of technology implementation (LoTI) occur in the WebQuests that participants designed.…

Higher-order geodesic deviations applied to the Kerr metric

CERN Document Server

Colistete, R J; Kerner, R

2002-01-01

Starting with an exact and simple geodesic, we generate approximate geodesics by summing up higher-order geodesic deviations within a general relativistic setting, without using Newtonian and post-Newtonian approximations. We apply this method to the problem of closed orbital motion of test particles in the Kerr metric spacetime. With a simple circular orbit in the equatorial plane taken as the initial geodesic, we obtain finite eccentricity orbits in the form of Taylor series with the eccentricity playing the role of a small parameter. The explicit expressions of these higher-order geodesic deviations are derived using successive systems of linear equations with constant coefficients, whose solutions are of harmonic oscillator type. This scheme gives best results when applied to orbits with low eccentricities, but with arbitrary possible values of (GM/Rc sup 2).

Analysis of higher order harmonics with holographic reflection gratings

Science.gov (United States)

Mas-Abellan, P.; Madrigal, R.; Fimia, A.

2017-05-01

Silver halide emulsions have been considered one of the most energetic sensitive materials for holographic applications. Nonlinear recording effects on holographic reflection gratings recorded on silver halide emulsions have been studied by different authors obtaining excellent experimental results. In this communication specifically we focused our investigation on the effects of refractive index modulation, trying to get high levels of overmodulation that will produce high order harmonics. We studied the influence of the overmodulation and its effects on the transmission spectra for a wide exposure range by use of 9 μm thickness films of ultrafine grain emulsion BB640, exposed to single collimated beams using a red He-Ne laser (wavelength 632.8 nm) with Denisyuk configuration obtaining a spatial frequency of 4990 l/mm recorded on the emulsion. The experimental results show that high overmodulation levels of refractive index produce second order harmonics with high diffraction efficiency (higher than 75%) and a narrow grating bandwidth (12.5 nm). Results also show that overmodulation produce diffraction spectra deformation of the second order harmonic, transforming the spectrum from sinusoidal to approximation of square shape due to very high overmodulation. Increasing the levels of overmodulation of refractive index, we have obtained higher order harmonics, obtaining third order harmonic with diffraction efficiency (up to 23%) and narrowing grating bandwidth (5 nm). This study is the first step to develop a new easy technique to obtain narrow spectral filters based on the use of high index modulation reflection gratings.

A New Higher-Order Composite Theory for Analysis and Design of High Speed Tilt-Rotor Blades

Science.gov (United States)

McCarthy, Thomas Robert

1996-01-01

A higher-order theory is developed to model composite box beams with arbitrary wall thicknesses. The theory, based on a refined displacement field, represents a three-dimensional model which approximates the elasticity solution. Therefore, the cross-sectional properties are not reduced to one-dimensional beam parameters. Both inplane and out-of-plane warping are automatically included in the formulation. The model accurately captures the transverse shear stresses through the thickness of each wall while satisfying all stress-free boundary conditions. Several numerical results are presented to validate the present theory. The developed theory is then used to model the load carrying member of a tilt-rotor blade which has thick-walled sections. The composite structural analysis is coupled with an aerodynamic analysis to compute the aeroelastic stability of the blade. Finally, a multidisciplinary optimization procedure is developed to improve the aerodynamic, structural and aeroelastic performance of the tilt-rotor aircraft. The Kreisselmeier-Steinhauser function is used to formulate the multiobjective function problem and a hybrid approximate analysis is used to reduce the computational effort. The optimum results are compared with the baseline values and show significant improvements in the overall performance of the tilt-rotor blade.

Analysis and mitigation of systematic errors in spectral shearing interferometry of pulses approaching the single-cycle limit [Invited

International Nuclear Information System (INIS)

Birge, Jonathan R.; Kaertner, Franz X.

2008-01-01

We derive an analytical approximation for the measured pulse width error in spectral shearing methods, such as spectral phase interferometry for direct electric-field reconstruction (SPIDER), caused by an anomalous delay between the two sheared pulse components. This analysis suggests that, as pulses approach the single-cycle limit, the resulting requirements on the calibration and stability of this delay become significant, requiring precision orders of magnitude higher than the scale of a wavelength. This is demonstrated by numerical simulations of SPIDER pulse reconstruction using actual data from a sub-two-cycle laser. We briefly propose methods to minimize the effects of this sensitivity in SPIDER and review variants of spectral shearing that attempt to avoid this difficulty

Flow through internal elastic lamina affects shear stress on smooth muscle cells (3D simulations).

Science.gov (United States)

Tada, Shigeru; Tarbell, John M

2002-02-01

We describe a three-dimensional numerical simulation of interstitial flow through the medial layer of an artery accounting for the complex entrance condition associated with fenestral pores in the internal elastic lamina (IEL) to investigate the fluid mechanical environment around the smooth muscle cells (SMCs) right beneath the IEL. The IEL was modeled as an impermeable barrier to water flow except for the fenestral pores, which were assumed to be uniformly distributed over the IEL. The medial layer was modeled as a heterogeneous medium composed of a periodic array of cylindrical SMCs embedded in a continuous porous medium representing the interstitial proteoglycan and collagen matrix. Depending on the distance between the IEL bottom surface and the upstream end of the proximal layer of SMCs, the local shear stress on SMCs right beneath the fenestral pore could be more than 10 times higher than that on the cells far removed from the IEL under the conditions that the fenestral pore diameter and area fraction of pores were kept constant at 1.4 microm and 0.05, respectively. Thus these proximal SMCs may experience shear stress levels that are even higher than endothelial cells exposed to normal blood flow (order of 10 dyn/cm(2)). Furthermore, entrance flow through fenestral pores alters considerably the interstitial flow field in the medial layer over a spatial length scale of the order of the fenestral pore diameter. Thus the spatial gradient of shear stress on the most superficial SMC is noticeably higher than computed for endothelial cell surfaces.

Higher-order thinking in foreign language learning

OpenAIRE

Bastos, Ascensão; Ramos, Altina

2017-01-01

A project is being conducted in English as a foreign language (EFL), involving eleventh graders in formal and non-formal learning contexts, in a Portuguese high school. The goal of this study is to examine the impact of cognitive tools and higher-order thinking processes on the learning of EFL and achievement of larger processes oriented to action, involving problem solving, decision-making and creation of new products. YouTube videos emerge as cognitive tools in the process. Final results sh...

Higher-order conditioning is impaired by hippocampal lesions.

Science.gov (United States)

Gilboa, Asaf; Sekeres, Melanie; Moscovitch, Morris; Winocur, Gordon

2014-09-22

Behavior in the real world is rarely motivated by primary conditioned stimuli that have been directly associated with potent unconditioned reinforcers. Instead, motivation and choice behavior are driven by complex chains of higher-order associations that are only indirectly linked to intrinsic reward and often exert their influence outside awareness. Second-order conditioning (SOC) [1] is a basic associative-learning mechanism whereby stimuli acquire motivational salience by proxy, in the absence of primary incentives [2, 3]. Memory-systems theories consider first-order conditioning (FOC) and SOC to be prime examples of hippocampal-independent nondeclarative memory [4, 5]. Accordingly, neurobiological models of SOC focus almost exclusively on nondeclarative neural systems that support motivational salience and reward value. Transfer of value from a conditioned stimulus to a neutral stimulus is thought to require the basolateral amygdala [6, 7] and the ventral striatum [2, 3], but not the hippocampus. We developed a new paradigm to measure appetitive SOC of tones in rats. Hippocampal lesions severely impaired both acquisition and expression of SOC despite normal FOC. Unlike controls, rats with hippocampal lesions could not discriminate between positive and negative secondary conditioned tones, although they exhibited general familiarity with previously presented tones compared with new tones. Importantly, normal rats' behavior, in contrast to that of hippocampal groups, also revealed different confidence levels as indexed by effort, a central characteristic of hippocampal relational memory. The results indicate, contrary to current systems models, that representations of intrinsic relationships between reward value, stimulus identity, and motivation require hippocampal mediation when these relationships are of a higher order. Copyright © 2014 Elsevier Ltd. All rights reserved.

Method of moments solution of volume integral equations using higher-order hierarchical Legendre basis functions

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Jørgensen, Erik; Meincke, Peter

2004-01-01

An efficient higher-order method of moments (MoM) solution of volume integral equations is presented. The higher-order MoM solution is based on higher-order hierarchical Legendre basis functions and higher-order geometry modeling. An unstructured mesh composed of 8-node trilinear and/or curved 27...... of magnitude in comparison to existing higher-order hierarchical basis functions. Consequently, an iterative solver can be applied even for high expansion orders. Numerical results demonstrate excellent agreement with the analytical Mie series solution for a dielectric sphere as well as with results obtained...

Higher- and Lower-Order Factor Analyses of the Temperament in Middle Childhood Questionnaire

Science.gov (United States)

Kotelnikova, Yuliya; Olino, Thomas M.; Klein, Daniel N.; Mackrell, Sarah V.M.; Hayden, Elizabeth P.

2017-01-01

The Temperament in Middle Childhood Questionnaire (TMCQ; Simonds & Rothbart, 2004) is a widely used parent-report measure of temperament. However, neither its lower- nor higher-order structures have been tested via a bottom-up, empirically based approach. We conducted higher- and lower-order exploratory factor analyses (EFAs) of the TMCQ in a large (N = 654) sample of 9-year-olds. Item-level EFAs identified 92 items as suitable (i.e., with loadings ≥.40) for constructing lower-order factors, only half of which resembled a TMCQ scale posited by the measure’s authors. Higher-order EFAs of the lower-order factors showed that a three-factor structure (Impulsivity/Negative Affectivity, Negative Affectivity, and Openness/Assertiveness) was the only admissible solution. Overall, many TMCQ items did not load well onto a lower-order factor. In addition, only three factors, which did not show a clear resemblance to Rothbart’s four-factor model of temperament in middle childhood, were needed to account for the higher-order structure of the TMCQ. PMID:27002124

Use of the McQuarrie equation for the computation of shear viscosity via equilibrium molecular dynamics

International Nuclear Information System (INIS)

Chialvo, A.A.; Debenedetti, P.G.

1991-01-01

To date, the calculation of shear viscosity for soft-core fluids via equilibrium molecular dynamics has been done almost exclusively using the Green-Kubo formalism. The alternative mean-squared displacement approach has not been used, except for hard-sphere fluids, in which case the expression proposed by Helfand [Phys. Rev. 119, 1 (1960)] has invariably been selected. When written in the form given by McQuarrie [Statistical Mechanics (Harper ampersand Row, New York, 1976), Chap. 21], however, the mean-squared displacement approach offers significant computational advantages over both its Green-Kubo and Helfand counterparts. In order to achieve comparable statistical significance, the number of experiments needed when using the Green-Kubo or Helfand formalisms is more than an order of magnitude higher than for the McQuarrie expression. For pairwise-additive systems with zero linear momentum, the McQuarrie method yields frame-independent shear viscosities. The hitherto unexplored McQuarrie implementation of the mean-squared displacement approach to shear-viscosity calculation thus appears superior to alternative methods currently in use

Influence of higher order modes on angled-facet amplifiers

DEFF Research Database (Denmark)

Wang, Z.; Mikkelsen, B.; Stubkjær, Kristian

1991-01-01

The influence of the first-order mode on the residual reflectivity of angled-facet amplifiers is analyzed. For a 7 degrees angled-facet ridge waveguide amplifier with a single-layer antireflective (AR) coating, a gain ripple lower than 1-dB at 25-dB gain can be obtained independent...... of the polarization, even in the presence of a first-order mode with a 15-dB gain. The tolerances for the thickness and refractive index of the AR coating are reduced by a factor of three compared to operation in the fundamental mode only. The influence of the higher order mode can virtually be suppressed...

Higher order capacity statistics of multi-hop transmission systems over Rayleigh fading channels

KAUST Repository

Yilmaz, Ferkan

2012-03-01

In this paper, we present an exact analytical expression to evaluate the higher order statistics of the channel capacity for amplify and forward (AF) multihop transmission systems operating over Rayleigh fading channels. Furthermore, we present simple and efficient closed-form expression to the higher order moments of the channel capacity of dual hop transmission system with Rayleigh fading channels. In order to analyze the behavior of the higher order capacity statistics and investigate the usefulness of the mathematical analysis, some selected numerical and simulation results are presented. Our results are found to be in perfect agreement. © 2012 IEEE.

Generating superpositions of higher order bessel beams [Conference paper

CSIR Research Space (South Africa)

Vasilyeu, R

2009-10-01

Full Text Available An experimental setup to generate a superposition of higher-order Bessel beams by means of a spatial light modulator and ring aperture is presented. The experimentally produced fields are in good agreement with those calculated theoretically....

Protein scaffolds and higher-order complexes in synthetic biology

NARCIS (Netherlands)

den Hamer, A.; Rosier, B.J.H.M.; Brunsveld, L.; de Greef, T.F.A.; Ryadnov, M.; Brunsveld, L.; Suga, H.

2017-01-01

Interactions between proteins control molecular functions such as signalling or metabolic activity. Assembly of proteins via scaffold proteins or in higher-order complexes is a key regulatory mechanism. Understanding and functionally applying this concept requires the construction, study, and

Higher-order terms in the nuclear-energy-density functional

International Nuclear Information System (INIS)

Carlsson, B. G.; Borucki, M.; Dobaczewski, J.

2009-01-01

One of the current projects at the Department of Physics in the University of Jyvaeskylae is to explore more general forms of the Skyrme energy-density functional (EDF). The aim is to find new phenomenological terms which are sensitive to experimental data. In this context we have extended the Skyrme functional by including terms which contain higher orders of derivatives allowing for a better description of finite range effects. This was done by employing an expansion in derivatives in a spherical-tensor formalism [1] motivated by ideas of the density-matrix expansion. The resulting functionals have different number of free parameters depending on the order in derivatives and assumed symmetries, see Fig. 1. The usual Skyrme EDF is obtained as a second order expansion while we keep terms up to sixth order.(author)

Higher-order techniques for some problems of nonlinear control

Directory of Open Access Journals (Sweden)

Sarychev Andrey V.

2002-01-01

Full Text Available A natural first step when dealing with a nonlinear problem is an application of some version of linearization principle. This includes the well known linearization principles for controllability, observability and stability and also first-order optimality conditions such as Lagrange multipliers rule or Pontryagin's maximum principle. In many interesting and important problems of nonlinear control the linearization principle fails to provide a solution. In the present paper we provide some examples of how higher-order methods of differential geometric control theory can be used for the study nonlinear control systems in such cases. The presentation includes: nonlinear systems with impulsive and distribution-like inputs; second-order optimality conditions for bang–bang extremals of optimal control problems; methods of high-order averaging for studying stability and stabilization of time-variant control systems.

Coupling between shear and bending in the analysis of beam problems: Planar case

Science.gov (United States)

Shabana, Ahmed A.; Patel, Mohil

2018-04-01

The interpretation of invariants, such as curvatures which uniquely define the bending and twist of space curves and surfaces, is fundamental in the formulation of the beam and plate elastic forces. Accurate representations of curve and surface invariants, which enter into the definition of the strain energy equations, is particularly important in the case of large displacement analysis. This paper discusses this important subject in view of the fact that shear and bending are independent modes of deformation and do not have kinematic coupling; this is despite the fact that kinetic coupling may exist. The paper shows, using simple examples, that shear without bending and bending without shear at an arbitrary point and along a certain direction are scenarios that higher-order finite elements (FE) can represent with a degree of accuracy that depends on the order of interpolation and/or mesh size. The FE representation of these two kinematically uncoupled modes of deformation is evaluated in order to examine the effect of the order of the polynomial interpolation on the accuracy of representing these two independent modes. It is also shown in this paper that not all the curvature vectors contribute to bending deformation. In view of the conclusions drawn from the analysis of simple beam problems, the material curvature used in several previous investigations is evaluated both analytically and numerically. The problems associated with the material curvature matrix, obtained using the rotation of the beam cross-section, and the fundamental differences between this material curvature matrix and the Serret-Frenet curvature matrix are discussed.

First-order and higher order sequence learning in specific language impairment.

Science.gov (United States)

Clark, Gillian M; Lum, Jarrad A G

2017-02-01

A core claim of the procedural deficit hypothesis of specific language impairment (SLI) is that the disorder is associated with poor implicit sequence learning. This study investigated whether implicit sequence learning problems in SLI are present for first-order conditional (FOC) and higher order conditional (HOC) sequences. Twenty-five children with SLI and 27 age-matched, nonlanguage-impaired children completed 2 serial reaction time tasks. On 1 version, the sequence to be implicitly learnt comprised a FOC sequence and on the other a HOC sequence. Results showed that the SLI group learned the HOC sequence (η p ² = .285, p = .005) but not the FOC sequence (η p ² = .099, p = .118). The control group learned both sequences (FOC η p ² = .497, HOC η p 2= .465, ps < .001). The SLI group's difficulty learning the FOC sequence is consistent with the procedural deficit hypothesis. However, the study provides new evidence that multiple mechanisms may underpin the learning of FOC and HOC sequences. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Shear viscosity and out of equilibrium dynamics

CERN Document Server

El, Andrej; Xu, Zhe; Greiner, Carsten

2009-01-01

Using the Grad's method we calculate the entropy production and derive a formula for the second order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance the shear tensor and the shear viscosity to entropy density ratio $\\eta/s$ are numerically calculated by an iterative and self-consistent prescription within the second order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with $\\eta/s$ obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling $\\alpha_s \\sim 0.3$(with $\\eta/s\\approx 0.18$) and is a factor of 2-3 larger at a small coupling $\\alpha_s \\sim 0.01$. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on $\\eta/s$, except when employing a small $\\alpha_s$. On the other hand, we demonstrate th...

Density changes in shear bands of a metallic glass determined by correlative analytical transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Rösner, Harald, E-mail: rosner@uni-muenster.de [Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster (Germany); Peterlechner, Martin [Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster (Germany); Kübel, Christian [Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology (INT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen (Germany); Schmidt, Vitalij [Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster (Germany); Wilde, Gerhard [Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster (Germany); Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China)

2014-07-01

Density changes between sheared zones and their surrounding amorphous matrix as a result of plastic deformation in a cold-rolled metallic glass (melt-spun Al{sub 88}Y{sub 7}Fe{sub 5}) were determined using high-angle annular dark-field (HAADF) detector intensities supplemented by electron-energy loss spectroscopy (EELS), energy-dispersive X-ray (EDX) and nano-beam diffraction analyses. Sheared zones or shear bands were observed as regions of bright or dark contrast arising from a higher or lower density relative to the matrix. Moreover, abrupt contrast changes from bright to dark and vice versa were found within individual shear bands. We associate the decrease in density mainly with an enhanced free volume in the shear bands and the increase in density with concomitant changes of the mass. This interpretation is further supported by changes in the zero loss and Plasmon signal originating from such sites. The limits of this new approach are discussed. - Highlights: • We describe a novel approach for measuring densities in shear bands of metallic glasses. • The linear relation of the dark-field intensity I/I{sub 0} and the mass thickness ρt was used. • Individual shear bands showed abrupt contrast changes from bright to dark and vice versa. • Density changes ranging from about −10% to +6% were found for such shear bands. • Mixtures of amorphous/medium range ordered domains were found within the shear bands.

Naesliden Project: direct shear tests of filled and unfilled joints

Energy Technology Data Exchange (ETDEWEB)

Ludvig, B.

1980-05-15

Joints from the Naesliden mine have been tested in a small field shear box and in a large shear rig. The large shear rig is described in detail, and its ability to test joints with an area of 600 mc/sup 2/ at a maximum normal stress of up to 20 MPa is emphasized. The stiffness and shear strength of the discontinuities in the Naesliden mine is presented. The values estimated at direct shear tests are compared with results from in situ measurements and tests on drillcores. The results show that the in situ measurements give lower values for the shear resistance than the direct shear tests. Estimation of the normal stiffness for joints in drill cores gave much higher stiffness than the estimations in the shear rig.

Higher-order resonant electronic recombination as a manifestation of configuration interaction

International Nuclear Information System (INIS)

Beilmann, C; Amaro, P; Tashenov, S; Bekker, H; Harman, Z; Crespo López-Urrutia, J R

2013-01-01

Theoretical and experimental investigations of higher-order electron–ion recombination resonances including inter-shell excitations are presented for L-shell ions of Kr with the aim of examining details of atomic structure calculations. The particular importance of electron–electron interaction and configuration mixing effects for these recombination processes enables their use for detailed tests of electron correlation effects. A test of the required level of considered mixing configurations is presented and further experiments involving higher-order recombination channels are motivated. (paper)

Higher order mode of a microstripline fed cylindrical dielectric resonator antenna

Energy Technology Data Exchange (ETDEWEB)

Kumar, A. V. Praveen, E-mail: praveen.kumar@pilani.bits-pilani.ac.in [Department of Electrical and Electronics Engineering, BITS Pilani, Pilani, Rajasthan-333 031 (India)

2016-03-09

A microstrip transmission line can be used to excite the broadside radiating mode of a cylindrical dielectric resonator antenna (CDRA). The same is found to excite considerably well a higher order mode (HOM) as well. However unlike the broadside mode, the higher order mode gives distorted radiation pattern which makes this mode less useful for practical applications. The cause of distortion in the HOM radiation and the dependence of HOM coupling on the microstrip feed line are explored using HFSS simulations.

Oscillation of solutions of some higher order linear differential equations

Directory of Open Access Journals (Sweden)

Hong-Yan Xu

2009-11-01

Full Text Available In this paper, we deal with the order of growth and the hyper order of solutions of higher order linear differential equations $$f^{(k}+B_{k-1}f^{(k-1}+\\cdots+B_1f'+B_0f=F$$ where $B_j(z (j=0,1,\\ldots,k-1$ and $F$ are entire functions or polynomials. Some results are obtained which improve and extend previous results given by Z.-X. Chen, J. Wang, T.-B. Cao and C.-H. Li.

Improved Multilevel Fast Multipole Method for Higher-Order discretizations

DEFF Research Database (Denmark)

Borries, Oscar Peter; Meincke, Peter; Jorgensen, Erik

2014-01-01

The Multilevel Fast Multipole Method (MLFMM) allows for a reduced computational complexity when solving electromagnetic scattering problems. Combining this with the reduced number of unknowns provided by Higher-Order discretizations has proven to be a difficult task, with the general conclusion b...

Higher-order momentum distributions and locally affine LDDMM registration

DEFF Research Database (Denmark)

Sommer, Stefan Horst; Nielsen, Mads; Darkner, Sune

2013-01-01

description of affine transformations and subsequent compact description of non-translational movement in a globally nonrigid deformation. The resulting representation contains directly interpretable information from both mathematical and modeling perspectives. We develop the mathematical construction......To achieve sparse parametrizations that allow intuitive analysis, we aim to represent deformation with a basis containing interpretable elements, and we wish to use elements that have the description capacity to represent the deformation compactly. To accomplish this, we introduce in this paper...... higher-order momentum distributions in the large deformation diffeomorphic metric mapping (LDDMM) registration framework. While the zeroth-order moments previously used in LDDMM only describe local displacement, the first-order momenta that are proposed here represent a basis that allows local...

Gamow-Jordan vectors and non-reducible density operators from higher-order S-matrix poles

International Nuclear Information System (INIS)

Bohm, A.; Loewe, M.; Maxson, S.; Patuleanu, P.; Puentmann, C.; Gadella, M.

1997-01-01

In analogy to Gamow vectors that are obtained from first-order resonance poles of the S-matrix, one can also define higher-order Gamow vectors which are derived from higher-order poles of the S-matrix. An S-matrix pole of r-th order at z R =E R -iΓ/2 leads to r generalized eigenvectors of order k=0,1,hor-ellipsis,r-1, which are also Jordan vectors of degree (k+1) with generalized eigenvalue (E R -iΓ/2). The Gamow-Jordan vectors are elements of a generalized complex eigenvector expansion, whose form suggests the definition of a state operator (density matrix) for the microphysical decaying state of this higher-order pole. This microphysical state is a mixture of non-reducible components. In spite of the fact that the k-th order Gamow-Jordan vectors has the polynomial time-dependence which one always associates with higher-order poles, the microphysical state obeys a purely exponential decay law. copyright 1997 American Institute of Physics

Critical wall shear stress for the EHEDG test method

DEFF Research Database (Denmark)

Jensen, Bo Boye Busk; Friis, Alan

2004-01-01

In order to simulate the results of practical cleaning tests on closed processing equipment, based on wall shear stress predicted by computational fluid dynamics, a critical wall shear stress is required for that particular cleaning method. This work presents investigations that provide a critical...... wall shear stress of 3 Pa for the standardised EHEDG cleaning test method. The cleaning tests were performed on a test disc placed in a radial flowcell assay. Turbulent flow conditions were generated and the corresponding wall shear stresses were predicted from CFD simulations. Combining wall shear...... stress predictions from a simulation using the low Re k-epsilon and one using the two-layer model of Norris and Reynolds were found to produce reliable predictions compared to empirical solutions for the ideal flow case. The comparison of wall shear stress curves predicted for the real RFC...

The Role of Formative Feedback in Promoting Higher Order ...

African Journals Online (AJOL)

DrNneka

An International Multi-disciplinary Journal, Ethiopia. AFRREV ... make contribution to this research gap by proposing a theoretical feedback model that can promote higher order thinking skills in the classroom. The proposed ..... process; students provided with tasks that are novel, complex, creative, and non- algorithmic ...

Statistical properties of wall shear stress fluctuations in turbulent channel flows

International Nuclear Information System (INIS)

Keirsbulck, L.; Labraga, L.; Gad-el-Hak, M.

2012-01-01

Highlights: ► Accurate measurements of instantaneous wall shear stress are conducted. ► LDA is used to measure near-wall streamwise velocity. ► Electrochemical probe is used to measure wall shear stress. ► Frequency response and non-uniform correction methods were used to provide an accurate, well-resolved wall-statistics database. ► Reynolds number dependency of the statistical wall quantities is investigated. - Abstract: Instantaneous velocity and wall shear stress measurements are conducted in a turbulent channel flow in the Kármán number range of Re τ = 74–400. A one-dimensional LDA system is used to measure the streamwise velocity fluctuations, and an electrochemical technique is utilized to measure the instantaneous wall shear stress. For the latter, frequency response and nonuniform correction methods are used to provide an accurate, well-resolved wall statistics database. The Reynolds number dependency of the statistical wall quantities is carefully investigated. The corrected relative wall shear stress fluctuations fit well with the best DNS data available and meet the need for clarification of the small discrepancy observed in the literature between the experimental and numerical results of such quantities. Higher-order statistics of the wall shear stress, spectra, and the turbulence kinetic energy budget at the wall are also investigated. The present paper shows that the electrochemical technique is a powerful experimental method for hydrodynamic studies involving highly unsteady flows. The study brings with it important consequences, especially in the context of the current debate regarding the appropriate scaling as well as the validation of new predictive models of near-wall turbulence.

A hierarchical generalization of the acoustic reciprocity theorem involving higher-order derivatives and interaction quantities.

Science.gov (United States)

Lin, Ju; Li, Jie; Li, Xiaolei; Wang, Ning

2016-10-01

An acoustic reciprocity theorem is generalized, for a smoothly varying perturbed medium, to a hierarchy of reciprocity theorems including higher-order derivatives of acoustic fields. The standard reciprocity theorem is the first member of the hierarchy. It is shown that the conservation of higher-order interaction quantities is related closely to higher-order derivative distributions of perturbed media. Then integral reciprocity theorems are obtained by applying Gauss's divergence theorem, which give explicit integral representations connecting higher-order interactions and higher-order derivative distributions of perturbed media. Some possible applications to an inverse problem are also discussed.

Higher-order phase transitions on financial markets

Science.gov (United States)

Kasprzak, A.; Kutner, R.; Perelló, J.; Masoliver, J.

2010-08-01

Statistical and thermodynamic properties of the anomalous multifractal structure of random interevent (or intertransaction) times were thoroughly studied by using the extended continuous-time random walk (CTRW) formalism of Montroll, Weiss, Scher, and Lax. Although this formalism is quite general (and can be applied to any interhuman communication with nontrivial priority), we consider it in the context of a financial market where heterogeneous agent activities can occur within a wide spectrum of time scales. As the main general consequence, we found (by additionally using the Saddle-Point Approximation) the scaling or power-dependent form of the partition function, Z(q'). It diverges for any negative scaling powers q' (which justifies the name anomalous) while for positive ones it shows the scaling with the general exponent τ(q'). This exponent is the nonanalytic (singular) or noninteger power of q', which is one of the pilar of higher-order phase transitions. In definition of the partition function we used the pausing-time distribution (PTD) as the central one, which takes the form of convolution (or superstatistics used, e.g. for describing turbulence as well as the financial market). Its integral kernel is given by the stretched exponential distribution (often used in disordered systems). This kernel extends both the exponential distribution assumed in the original version of the CTRW formalism (for description of the transient photocurrent measured in amorphous glassy material) as well as the Gaussian one sometimes used in this context (e.g. for diffusion of hydrogen in amorphous metals or for aging effects in glasses). Our most important finding is the third- and higher-order phase transitions, which can be roughly interpreted as transitions between the phase where high frequency trading is most visible and the phase defined by low frequency trading. The specific order of the phase transition directly depends upon the shape exponent α defining the stretched

Exact Solutions to Nonlinear Schroedinger Equation and Higher-Order Nonlinear Schroedinger Equation

International Nuclear Information System (INIS)

Ren Ji; Ruan Hangyu

2008-01-01

We study solutions of the nonlinear Schroedinger equation (NLSE) and higher-order nonlinear Schroedinger equation (HONLSE) with variable coefficients. By considering all the higher-order effect of HONLSE as a new dependent variable, the NLSE and HONLSE can be changed into one equation. Using the generalized Lie group reduction method (GLGRM), the abundant solutions of NLSE and HONLSE are obtained

A mathematical model for fluid shear-sensitive 3D tissue construct development.

Science.gov (United States)

Liu, Dan; Chua, Chee-Kai; Leong, Kah-Fai

2013-01-01

This research studies dynamic culture for 3D tissue construct development with computational fluid dynamics. It proposes a mathematical model to evaluate the impact of flow rates and flow shear stress on cell growth in 3D constructs under perfusion. The modeling results show that dynamic flow, even at flow rate as low as 0.002 cm/s, can support much better mass exchange, higher cell number, and more even cell and nutrient distribution compared to static culture. Higher flow rate can further improve nutrient supply and mass exchange in the construct, promoting better nutritious environment and cell proliferation compared to lower flow rate. In addition, consideration of flow shear stress predicts much higher cell number in the construct compared to that without shear consideration. While the nutrient can dominate shear stress in influencing cell proliferation, the shear effect increases with flow rate. The proposed model helps tissue engineers better understand the cell-flow relationship at the molecular level during dynamic culture.

On realization of nonlinear systems described by higher-order differential equations

NARCIS (Netherlands)

van der Schaft, Arjan

1987-01-01

We consider systems of smooth nonlinear differential and algebraic equations in which some of the variables are distinguished as “external variables.” The realization problem is to replace the higher-order implicit differential equations by first-order explicit differential equations and the

Constrained variational calculus for higher order classical field theories

Energy Technology Data Exchange (ETDEWEB)

Campos, Cedric M; De Leon, Manuel; De Diego, David MartIn, E-mail: cedricmc@icmat.e, E-mail: mdeleon@icmat.e, E-mail: david.martin@icmat.e [Instituto de Ciencias Matematicas, CSIC-UAM-UC3M-UCM, Serrano 123, 28006 Madrid (Spain)

2010-11-12

We develop an intrinsic geometrical setting for higher order constrained field theories. As a main tool we use an appropriate generalization of the classical Skinner-Rusk formalism. Some examples of applications are studied, in particular to the geometrical description of optimal control theory for partial differential equations.

Constrained variational calculus for higher order classical field theories

International Nuclear Information System (INIS)

Campos, Cedric M; De Leon, Manuel; De Diego, David MartIn

2010-01-01

We develop an intrinsic geometrical setting for higher order constrained field theories. As a main tool we use an appropriate generalization of the classical Skinner-Rusk formalism. Some examples of applications are studied, in particular to the geometrical description of optimal control theory for partial differential equations.

Decidable Fragments of a Higher Order Calculus with Locations

DEFF Research Database (Denmark)

Bundgaard, Mikkel; Godskesen, Jens Christian; Huttel, Hans

2009-01-01

Homer is a higher order process calculus with locations. In this paper we study Homer in the setting of the semantic finite control property, which is a finite reachability criterion that implies decidability of barbed bisimilarity. We show that strong and weak barbed bisimilarity are undecidable...

Quantum Noether identities for non-local transformations in higher-order derivatives theories

International Nuclear Information System (INIS)

Li, Z.P.; Long, Z.W.

2003-01-01

Based on the phase-space generating functional of the Green function for a system with a regular/singular higher-order Lagrangian, the quantum canonical Noether identities (NIs) under a local and non-local transformation in phase space have been deduced, respectively. For a singular higher-order Lagrangian, one must use an effective canonical action I eff P in quantum canonical NIs instead of the classical I P in classical canonical NIs. The quantum NIs under a local and non-local transformation in configuration space for a gauge-invariant system with a higher-order Lagrangian have also been derived. The above results hold true whether or not the Jacobian of the transformation is equal to unity or not. It has been pointed out that in certain cases the quantum NIs may be converted to conservation laws at the quantum level. This algorithm to derive the quantum conservation laws is significantly different from the quantum first Noether theorem. The applications of our formulation to the Yang-Mills fields and non-Abelian Chern-Simons (CS) theories with higher-order derivatives are given, and the conserved quantities at the quantum level for local and non-local transformations are found, respectively. (orig.)

The role of formative feedback in promoting higher order thinking ...

African Journals Online (AJOL)

The role of formative feedback in promoting higher order thinking skills in ... activities, task characteristics, validating students' thinking, and providing feedback. ... Keywords: classroom environment, formative assessment, formative feedback, ...

Effect of rock joint roughness on its cyclic shear behavior

Directory of Open Access Journals (Sweden)

S.M. Mahdi Niktabar

2017-12-01

Full Text Available Rock joints are often subjected to dynamic loads induced by earthquake and blasting during mining and rock cutting. Hence, cyclic shear load can be induced along the joints and it is important to evaluate the shear behavior of rock joint under this condition. In the present study, synthetic rock joints were prepared with plaster of Paris (PoP. Regular joints were simulated by keeping regular asperity with asperity angles of 15°–15° and 30°–30°, and irregular rock joints which are closer to natural joints were replicated by keeping the asperity angles of 15°–30° and 15°–45°. The sample size and amplitude of roughness were kept the same for both regular and irregular joints which were 298 mm × 298 mm × 125 mm and 5 mm, respectively. Shear test was performed on these joints using a large-scale direct shear testing machine by keeping the frequency and amplitude of shear load under constant cyclic condition with different normal stress values. As expected, the shear strength of rock joints increased with the increases in the asperity angle and normal load during the first cycle of shearing or static load. With the increase of the number of shear cycles, the shear strength decreased for all the asperity angles but the rate of reduction was more in case of high asperity angles. Test results indicated that shear strength of irregular joints was higher than that of regular joints at different cycles of shearing at low normal stress. Shearing and degradation of joint asperities on regular joints were the same between loading and unloading, but different for irregular joints. Shear strength and joint degradation were more significant on the slope of asperity with higher angles on the irregular joint until two angles of asperities became equal during the cycle of shearing and it started behaving like regular joints for subsequent cycles.

Algebraic Specifications, Higher-order Types and Set-theoretic Models

DEFF Research Database (Denmark)

Kirchner, Hélène; Mosses, Peter David

2001-01-01

, and power-sets. This paper presents a simple framework for algebraic specifications with higher-order types and set-theoretic models. It may be regarded as the basis for a Horn-clause approximation to the Z framework, and has the advantage of being amenable to prototyping and automated reasoning. Standard......In most algebraic  specification frameworks, the type system is restricted to sorts, subsorts, and first-order function types. This is in marked contrast to the so-called model-oriented frameworks, which provide higer-order types, interpreted set-theoretically as Cartesian products, function spaces...... set-theoretic models are considered, and conditions are given for the existence of initial reduct's of such models. Algebraic specifications for various set-theoretic concepts are considered....

Squeezing of higher order Hermite-Gauss modes

DEFF Research Database (Denmark)

Lassen, Mikael Østergaard

2008-01-01

The present paper gives an overview of the experimental generation of squeezing in higher order Hermite-Gaussian modes with an optical parametric ampli¯er (OPA). This work was awarded with The European Optical Society (EOS) price 2007. The purpose of the prize is to encourage a European dimension...... in research in pure and applied optics. The EOS prize is awarded based on the selection criteria of high professionalism, academic and technical quality. Following the EOS Prize rules, the conditions for eligibility are that the work was performed in Europe and that it is published under the auspices...

Seismic behavior of semi-supported steel shear walls

DEFF Research Database (Denmark)

Jahanpour, A.; Jönsson, J.; Moharrami, H.

2012-01-01

During the recent past decade semi-supported steel shear walls (SSSW) have been introduced as an alternative to the traditional type of steel plate shear walls. In this system the shear wall does not connect directly to the main columns of the building frame; instead it is connected to a pair...... of secondary columns that do not carry vertical gravity loads. In this paper, the interaction between the wall plate and the surrounding frame is investigated experimentally for typical SSSW systems in which the wall-frame has a bending-dominant behavior. Based on the possible storey failure mechanisms...... a simple method is proposed for design of the floor beams. A quasi static cyclic experimental study has been performed in order to investigate the collapse behavior of the wall-plate and surrounding frame. Furthermore the test setup has been developed in order to facilitate standardized cyclic tests...

Comparison Criteria for Nonlinear Functional Dynamic Equations of Higher Order

Directory of Open Access Journals (Sweden)

Taher S. Hassan

2016-01-01

Full Text Available We will consider the higher order functional dynamic equations with mixed nonlinearities of the form xnt+∑j=0Npjtϕγjxφjt=0, on an above-unbounded time scale T, where n≥2, xi(t≔ri(tϕαixi-1Δ(t,  i=1,…,n-1,   with  x0=x,  ϕβ(u≔uβsgn⁡u, and α[i,j]≔αi⋯αj. The function φi:T→T is a rd-continuous function such that limt→∞φi(t=∞ for j=0,1,…,N. The results extend and improve some known results in the literature on higher order nonlinear dynamic equations.

Higher-Order Structure in Bacterial VapBC Toxin-Antitoxin Complexes

DEFF Research Database (Denmark)

Bendtsen, Kirstine L; Brodersen, Ditlev E

2017-01-01

Toxin-antitoxin systems are widespread in the bacterial kingdom, including in pathogenic species, where they allow rapid adaptation to changing environmental conditions through selective inhibition of key cellular processes, such as DNA replication or protein translation. Under normal growth...... that allow auto-regulation of transcription by direct binding to promoter DNA. In this chapter, we review our current understanding of the structural characteristics of type II toxin-antitoxin complexes in bacterial cells, with a special emphasis on the staggering variety of higher-order architecture...... conditions, type II toxins are inhibited through tight protein-protein interaction with a cognate antitoxin protein. This toxin-antitoxin complex associates into a higher-order macromolecular structure, typically heterotetrameric or heterooctameric, exposing two DNA binding domains on the antitoxin...

Higher-order relativistic periastron advances and binary pulsars

International Nuclear Information System (INIS)

Damour, T.; Schafer, G.

1988-01-01

The contributions to the periastron advance of a system of two condensed bodies coming from relativistic dynamical effects of order higher than the usual first post-Newtonian (1PN) equations of motion are investigated. The structure of the solution of the orbital second post-Newtonian (2PN) equations of motion is given in a simple parametrized form. The contributions to the secular pariastron advance, and the period, of orbital 2PN effects are then explicitly worked out by using the Hamilton-Jacobi method. The spin-orbit contribution to the secular precession of the orbit in space is rederived in a streamlined way by making full use of Hamiltonian methods. These results are then applied to the theoretical interpretation of the observational data of pulsars in close eccentric binary systems. It is shown that the higher-order relativistic contributions are already of theoretical and astophysical significance for interpreting the high-precision measurement of the secular periastron advance of PSR 1913+16 achived by Taylor and coworkers. The case of extremely fast spinning (millisecond) binary pulsars is also discussed, and shown to offer an easier ground for getting new tests of general relativity, and/or, a direct measurement of the moment of inertia of a neutron star

Shear Resistance Variations in Experimentally Sheared Mudstone Granules: A Possible Shear-Thinning and Thixotropic Mechanism

Science.gov (United States)

Hu, Wei; Xu, Qiang; Wang, Gonghui; Scaringi, Gianvito; Mcsaveney, Mauri; Hicher, Pierre-Yves

2017-11-01

We present results of ring shear frictional resistance for mudstone granules of different size obtained from a landslide shear zone. Little rate dependency of shear resistance was observed in sand-sized granules in any wet or dry test, while saturated gravel-sized granules exhibited significant and abrupt reversible rate-weakening (from μ = 0.6 to 0.05) at about 2 mm/s. Repeating resistance variations occurred also under constant shear displacement rate. Mudstone granules generate mud as they are crushed and softened. Shear-thinning and thixotropic behavior of the mud can explain the observed behavior: with the viscosity decreasing, the mud can flow through the coarser soil pores and migrate out from the shear zone. This brings new granules into contact which produces new mud. Thus, the process can start over. Similarities between experimental shear zones and those of some landslides in mudstone suggest that the observed behavior may play a role in some landslide kinematics.

Shear viscosities of photons in strongly coupled plasmas

Directory of Open Access Journals (Sweden)

Di-Lun Yang

2016-09-01

Full Text Available We investigate the shear viscosity of thermalized photons in the quark gluon plasma (QGP at weak coupling and N=4 super Yang–Mills plasma (SYMP at both strong and weak couplings. We find that the shear viscosity due to the photon–parton scattering up to the leading order of electromagnetic coupling is suppressed when the coupling of the QGP/SYMP is increased, which stems from the blue-shift of the thermal-photon spectrum at strong coupling. In addition, the shear viscosity rapidly increases near the deconfinement transition in a phenomenological model analogous to the QGP.

Defining Higher-Order Turbulent Moment Closures with an Artificial Neural Network and Random Forest

Science.gov (United States)

McGibbon, J.; Bretherton, C. S.

2017-12-01

Unresolved turbulent advection and clouds must be parameterized in atmospheric models. Modern higher-order closure schemes depend on analytic moment closure assumptions that diagnose higher-order moments in terms of lower-order ones. These are then tested against Large-Eddy Simulation (LES) higher-order moment relations. However, these relations may not be neatly analytic in nature. Rather than rely on an analytic higher-order moment closure, can we use machine learning on LES data itself to define a higher-order moment closure?We assess the ability of a deep artificial neural network (NN) and random forest (RF) to perform this task using a set of observationally-based LES runs from the MAGIC field campaign. By training on a subset of 12 simulations and testing on remaining simulations, we avoid over-fitting the training data.Performance of the NN and RF will be assessed and compared to the Analytic Double Gaussian 1 (ADG1) closure assumed by Cloudy Layers Unified By Binormals (CLUBB), a higher-order turbulence closure currently used in the Community Atmosphere Model (CAM). We will show that the RF outperforms the NN and the ADG1 closure for the MAGIC cases within this diagnostic framework. Progress and challenges in using a diagnostic machine learning closure within a prognostic cloud and turbulence parameterization will also be discussed.

Comparison of two test designs for evaluating the shear bond strength of resin composite cements.

Science.gov (United States)

Hu, M; Weiger, R; Fischer, J

2016-02-01

To compare a shear bond strength test for resin composite cements developed in order to better consider the shrinkage stress (here termed "Swiss shear test") with the shear test design according to ISO 29022. Four restorative materials (VITA Enamic (VE), VITA Suprinity (VS), Vitablocs Mark II (VM) and VITA YZ T (YZ)) served as substrate. VE, VS and VM were polished or etched. YZ was polished, sandblasted or etched. Specimens were either bonded according to the Swiss or the ISO shear test. RelyX Unicem 2 Automix, Maxcem Elite and PermaFlo DC were used as cements. Shear bond strength (SBS) was measured. Failure modes (adhesive, cohesive or mixed) were evaluated by means of SEM. Mean SBS values obtained with the Swiss shear test were significantly lower than those obtained with the ISO shear test. VE and VM exhibited similar SBS, values of VS were significantly higher. On etched surfaces VM and VE exhibited primarily cohesive failures, VS primarily adhesive failures. On polished substrates significantly lower bond strength values and exclusively adhesive failures were observed. YZ exhibited solely adhesive failures. Compared to polished YZ, SBS significantly increased after sandblasting and even more after etching. Only for adhesively failed specimens mean SBS values of Swiss and ISO shear test were strongly correlated. Both test designs showed the same ranking of test results. When adhesive failure occurred test results were strongly correlated. When cohesive failure was involved, both test designs did not provide reliable results. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Higher-order blackhole solutions in N=2 supergravity and Calabi-Yau string backgrounds

NARCIS (Netherlands)

Behrndt, K.; Cardoso, G.L.; de Wit, B.Q.P.J.; Lüst, D.; Mohaupt, T.; Sabra, W.A.

1998-01-01

Based on special geometry, we consider corrections to N=2 extremal black-hole solutions and their entropies originating from higher-order derivative terms in N=2 supergravity. These corrections are described by a holomorphic function, and the higher-order black-hole solutions can be expressed in

Shear viscosity of liquid mixtures: Mass dependence

International Nuclear Information System (INIS)

Kaushal, Rohan; Tankeshwar, K.

2002-06-01

Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model. (author)

Shear viscosity of liquid mixtures Mass dependence

CERN Document Server

Kaushal, R

2002-01-01

Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model.

Non-Poisson Dichotomous Noise: Higher-Order Correlation Functions and Aging

National Research Council Canada - National Science Library

Allegrini, Paolo; Grigolini, Paolo; Palatella, Luigi; West, Bruce J

2004-01-01

.... The transition of psi(tau) from the exponential to the nonexponential condition yields the breakdown of the usual factorization condition of higher-order correlation functions, as well as the birth of aging effects...

Visibility-Based Hypothesis Testing Using Higher-Order Optical Interference

Science.gov (United States)

Jachura, Michał; Jarzyna, Marcin; Lipka, Michał; Wasilewski, Wojciech; Banaszek, Konrad

2018-03-01

Many quantum information protocols rely on optical interference to compare data sets with efficiency or security unattainable by classical means. Standard implementations exploit first-order coherence between signals whose preparation requires a shared phase reference. Here, we analyze and experimentally demonstrate the binary discrimination of visibility hypotheses based on higher-order interference for optical signals with a random relative phase. This provides a robust protocol implementation primitive when a phase lock is unavailable or impractical. With the primitive cost quantified by the total detected optical energy, optimal operation is typically reached in the few-photon regime.

Inseparability inequalities for higher order moments for bipartite systems

International Nuclear Information System (INIS)

Agarwal, G S; Biswas, Asoka

2005-01-01

There are several examples of bipartite entangled states of continuous variables for which the existing criteria for entanglement using the inequalities involving the second-order moments are insufficient. We derive new inequalities involving higher order correlation, for testing entanglement in non-Gaussian states. In this context, we study an example of a non-Gaussian state, which is a bipartite entangled state of the form Ψ(x a , x b ) ∝ (αx a + βx b ) e -(x a 2 +x b 2 )/2 . Our results open up an avenue to search for new inequalities to test entanglement in non-Gaussian states

Higher order corrections to energy levels of muonic atoms

International Nuclear Information System (INIS)

Rinker, G.A. Jr.; Steffen, R.M.

1975-08-01

In order to facilitate the analysis of muonic x-ray spectra, the results of numerical computations of all higher order quantum electrodynamical corrections to the energy levels of muonic atoms are presented in tabular and graphical form. These corrections include the vacuum polarization corrections caused by emission and reabsorption of virtual electron pairs to all orders, including ''double-bubble'' and ''cracked-egg'' diagrams. An estimate of the Delbruecke scattering-type correction is presented. The Lamb-shift (second- and fourth-order vertex) corrections have been calculated including the correction for the anomalous magnetic moment of the muon. The relativistic nuclear motion (or recoil) correction as well as the correction caused by the screening of the atomic electrons is presented in graphs. For the sake of completeness a graph of the nuclear polarization as computed on the basis of Chen's approach has been included. All calculations were made with a two-parameter Fermi distribution of the nuclear charge density. 7 figures, 23 references

Simulation of shear and turbulence impact on wind turbine performance

DEFF Research Database (Denmark)

Wagner, Rozenn; Courtney, Michael; Larsen, Torben J.

Aerodynamic simulations (HAWC2Aero) were used to investigate the influence of the speed shear, the direction shear and the turbulence intensity on the power output of a multi-megawatt turbine. First simulation cases with laminar flow and power law wind speed profiles were compared to the case...... of a uniform inflow. Secondly, a similar analysis was done for cases with direction shear. In each case, we derived a standard power curve (function of the wind speed at hub height) and power curves obtained with various definitions of equivalent wind speed in order to reduce the scatter due to shear. Thirdly...

Modeling of the reactant conversion rate in a turbulent shear flow

Science.gov (United States)

Frankel, S. H.; Madnia, C. K.; Givi, P.

1992-01-01

Results are presented of direct numerical simulations (DNS) of spatially developing shear flows under the influence of infinitely fast chemical reactions of the type A + B yields Products. The simulation results are used to construct the compositional structure of the scalar field in a statistical manner. The results of this statistical analysis indicate that the use of a Beta density for the probability density function (PDF) of an appropriate Shvab-Zeldovich mixture fraction provides a very good estimate of the limiting bounds of the reactant conversion rate within the shear layer. This provides a strong justification for the implementation of this density in practical modeling of non-homogeneous turbulent reacting flows. However, the validity of the model cannot be generalized for predictions of higher order statistical quantities. A closed form analytical expression is presented for predicting the maximum rate of reactant conversion in non-homogeneous reacting turbulence.

Shear viscosity and out of equilibrium dynamics

CERN Document Server

El, Andrej; Xu, Zhe; Greiner, Carsten

2009-01-01

Using Grad’s method, we calculate the entropy production and derive a formula for the second-order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance, the shear tensor and the shear viscosity to entropy density ratio η/s are numerically calculated by an iterative and self-consistent prescription within the second-order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with η/s obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling αs ∼ 0.3 (with η/s ≈ 0.18) and is a factor of 2–3 larger at a small coupling αs ∼ 0.01. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on η/s, except when employing a small αs . On the other hand, we demonstrate that for such small αs , the gluon syst...

Impedance Eduction in Large Ducts Containing Higher-Order Modes and Grazing Flow

Science.gov (United States)

Watson, Willie R.; Jones, Michael G.

2017-01-01

Impedance eduction test data are acquired in ducts with small and large cross-sectional areas at the NASA Langley Research Center. An improved data acquisition system in the large duct has resulted in increased control of the acoustic energy in source modes and more accurate resolution of higher-order duct modes compared to previous tests. Two impedance eduction methods that take advantage of the improved data acquisition to educe the liner impedance in grazing flow are presented. One method measures the axial propagation constant of a dominant mode in the liner test section (by implementing the Kumarsean and Tufts algorithm) and educes the impedance from an exact analytical expression. The second method solves numerically the convected Helmholtz equation and minimizes an objective function to obtain the liner impedance. The two methods are tested first on data synthesized from an exact mode solution and then on measured data. Results show that when the methods are applied to data acquired in the larger duct with a dominant higher-order mode, the same impedance spectra are educed as that obtained in the small duct where only the plane wave mode propagates. This result holds for each higher-order mode in the large duct provided that the higher-order mode is sufficiently attenuated by the liner.

Effects of ExB velocity shear and magnetic shear on turbulence and transport in magnetic confinement devices

International Nuclear Information System (INIS)

Burrell, K.H.

1996-11-01

One of the scientific success stories of fusion research over the past decade is the development of the ExB shear stabilization model to explain the formation of transport barriers in magnetic confinement devices. This model was originally developed to explain the transport barrier formed at the plasma edge in tokamaks after the L (low) to H (high) transition. This concept has the universality needed to explain the edge transport barriers seen in limiter and divertor tokamaks, stellarators, and mirror machines. More recently, this model has been applied to explain the further confinement improvement from H (high)-mode to VH (very high)-mode seen in some tokamaks, where the edge transport barrier becomes wider. Most recently, this paradigm has been applied to the core transport barriers formed in plasmas with negative or low magnetic shear in the plasma core. These examples of confinement improvement are of considerable physical interest; it is not often that a system self-organizes to a higher energy state with reduced turbulence and transport when an additional source of free energy is applied to it. The transport decrease that is associated with ExB velocity shear effects also has significant practical consequences for fusion research. The fundamental physics involved in transport reduction is the effect of ExB shear on the growth, radial extent and phase correlation of turbulent eddies in the plasma. The same fundamental transport reduction process can be operational in various portions of the plasma because there are a number ways to change the radial electric field Er. An important theme in this area is the synergistic effect of ExB velocity shear and magnetic shear. Although the ExB velocity shear appears to have an effect on broader classes of microturbulence, magnetic shear can mitigate some potentially harmful effects of ExB velocity shear and facilitate turbulence stabilization

Higher order effects of pseudoparticles in QCD

International Nuclear Information System (INIS)

Hietarinta, J.; Palmer, W.F.

1977-01-01

Gauge invariant Green's functions of quark-antiquark bilinear densities in massless, two-color QCD are studied. Nonzero-energy fermion modes, pseudoparticle solutions with topological charge absolute value ν > 1, and n-point functions with n > 2. Some general properties of the O(Dirac constant) approximation are developed, enabling one to isolate and define the terms which contribute to a general n-point function. The higher effects it is found preserve the symmetry breakdown found earlier in the 2-point function (U(2) x U(2) → SU(2) x SU(2) x U(1)). It is shown that a previous 2-point function analysis is exact to order Dirac constant

Higher order modes of coupled optical fibres

International Nuclear Information System (INIS)

Alexeyev, C N; Yavorsky, M A; Boklag, N A

2010-01-01

The structure of hybrid higher order modes of two coupled weakly guiding identical optical fibres is studied. On the basis of perturbation theory with degeneracy for the vector wave equation expressions for modes with azimuthal angular number l ≥ 1 are obtained that allow for the spin–orbit interaction. The spectra of polarization corrections to the scalar propagation constants are calculated in a wide range of distances between the fibres. The limiting cases of widely and closely spaced fibres are studied. The obtained results can be used for studying the tunnelling of optical vortices in directional couplers and in matters concerned with information security

Evaluation of composite shear walls behavior (parametric study

Directory of Open Access Journals (Sweden)

Ali Nikkhoo

2017-11-01

Full Text Available Composite shear walls which are made of a layer of steel plate with a concrete cover in one or both sides of the steel plate, are counted as the third generation of the shear walls. Nowadays, composite shear walls are widely utilized in building new resisting structures as well as rehabilitating of the existing structures in earthquake-prone countries. Despite of its advantages, use of the composite shear walls is not yet prevalent as it demands more detailed appropriate investigation. Serving higher strength, flexibility and better energy absorption, while being more economical are the main advantages of this system which has paved its path to be used in high-rise buildings, structural retrofit and reservoir tanks. In this research, channel shear connectors are utilized to connect the concrete cover to the steel plate. As a key parameter, variation in the distance of shear connectors and their arrangement on the behavior of composite shear walls has been scrutinized. In addition, the shear stiffness, flexibility, out of plane displacement and the energy absorption of the structural system has been explored. For this purpose, several structural models with different shear distances and arrangements have been investigated. The obtained results reveal that with increase in shear connectors’ distance, the wall stiffness would reduce while its lateral displacement increases up to eighty percent While the out of plane displacement of the steel plate will reduce up to three times.

Shear rheological properties of fresh human faeces with different ...

African Journals Online (AJOL)

Samples were further tested for moisture content, total solids, volatile content, and ash content. Faecal samples were found to have a yield stress; there was a decrease in apparent viscosity with increasing shear rate. For any given shear rate, higher apparent viscosities are associated with lower moisture contents. Across a ...

Edge Sheared Flows and Blob Dynamics

Energy Technology Data Exchange (ETDEWEB)

Myra, J.; D' Ippolito, D.; Russell, D., E-mail: jrmyra@lodestar.com [Lodestar Research Corporation, Boulder (United States); Davis, W. M.; Zweben, S. [Princeton Plasma Physics Laboratory, Princeton (United States); Terry, J.; LaBombard, B. [Massachusetts Institute of Technology, Cambridge (United States)

2012-09-15

Full text: A study of sheared flows in the edge and scrape-off layer (SOL) and their interaction with blob-filaments is presented. Edge sheared flows are believed to be important for the L-H, and H-L transitions. Blob generation and dynamics impacts both the (near-separatrix) scrape-off-layer (SOL) width critical for power handling in the divertor, and the interaction of plasma in the far SOL with plasma-facing components. These topics are critical for ITER and future devices. A fluid-based 2D curvature-interchange model embedded in the SOLT code is employed to study these issues. Sheared binormal flows both regulate the power flux crossing the separatrix and control the character of emitted turbulence structures such as blob-filaments. At a critical power level (depending on parameters) the laminar flows containing intermittent, but bound, structures give way to full-blown blob emissions signifying a transition from quasi-diffusive to convective transport. In order to diagnose sheared flows in experiments and assess their interaction with blobs, a blob-tracking algorithm has been developed and applied to both NSTX and Alcator C-Mod data. Blob motion and ellipticity can be affected by sheared flows, and are diagnosed and compared with seeded blob simulations. A picture of the interaction of blobs and sheared flows is emerging from advances in the theory and simulation of edge turbulence, combined with ever-improving capabilities for edge diagnostics and their analysis. (author)

Teaching Higher Order Thinking in the Introductory MIS Course: A Model-Directed Approach

Science.gov (United States)

Wang, Shouhong; Wang, Hai

2011-01-01

One vision of education evolution is to change the modes of thinking of students. Critical thinking, design thinking, and system thinking are higher order thinking paradigms that are specifically pertinent to business education. A model-directed approach to teaching and learning higher order thinking is proposed. An example of application of the…

Higher-order threshold resummation for semi-inclusive e+e- annihilation

International Nuclear Information System (INIS)

Moch, S.; Vogt, A.

2009-08-01

The complete soft-enhanced and virtual-gluon contributions are derived for the quark coefficient functions in semi-inclusive e + e - annihilation to the third order in massless perturbative QCD. These terms enable us to extend the soft-gluon resummation for the fragmentation functions by two orders to the next-to-next-to-next-to-leading logarithmic (N 3 LL) accuracy. The resummation exponent is found to be the same as for the structure functions in inclusive deep-inelastic scattering. This finding, together with known results on the higher-order quark form factor, facilitates the determination of all soft and virtual contributions of the fourth-order difference of the coefficient functions for these two processes. Unlike the previous (N 2 LL) order in the exponentiation, the numerical effect of the N 3 LL contributions turns out to be negligible at LEP energies. (orig.)

A Novel Geometry for Shear Test Using Axial Tensile Setup

Directory of Open Access Journals (Sweden)

Sibo Yuan

2018-05-01

Full Text Available This paper studies a novel geometry for the in-plane shear test performed with an axial electromechanical testing machine. In order to investigate the influence of the triaxiality rate on the mechanical behavior, different tests will be performed on the studied material: simple tensile tests, large tensile tests and shear tests. For the whole campaign, a common equipment should be employed to minimize the impact of the testing device. As a consequence, for the shear tests, the geometry of the specimen must be carefully designed in order to adapt the force value and make it comparable to the one obtained for the tensile tests. Like most of the existing shear-included tensile test specimens, the axial loading is converted to shear loading at a particular region through the effect of geometry. A symmetric shape is generally preferred, since it can restrict the in-plane rotation of the shear section, keep shear increasing in a more monotonic path and double the force level thanks to the two shear zones. Due to the specific experimental conditions, such as dimensions of the furnace and the clamping system, the position of the extensometer or the restriction of sheet thickness (related to the further studies of size effect at mesoscale and hot temperature, several geometries were brought up and evaluated in an iterative procedure via finite element simulations. Both the numerical and experimental results reveal that the final geometry ensures some advantages. For instance, a relatively low triaxiality in the shear zone, limited in-plane rotation and no necking are observed. Moreover, it also prevents any out-of-plane displacement of the specimen which seems to be highly sensitive to the geometry, and presents a very limited influence of the material and the thickness.

Study on shear properties of coral sand under cyclic simple shear condition

Science.gov (United States)

Ji, Wendong; Zhang, Yuting; Jin, Yafei

2018-05-01

In recent years, the ocean development in our country urgently needs to be accelerated. The construction of artificial coral reefs has become an important development direction. In this paper, experimental studies of simple shear and cyclic simple shear of coral sand are carried out, and the shear properties and particle breakage of coral sand are analyzed. The results show that the coral sand samples show an overall shear failure in the simple shear test, which is more accurate and effective for studying the particle breakage. The shear displacement corresponding to the peak shear stress of the simple shear test is significantly larger than that corresponding to the peak shear stress of the direct shear test. The degree of particle breakage caused by the simple shear test is significantly related to the normal stress level. The particle breakage of coral sand after the cyclic simple shear test obviously increases compared with that of the simple shear test, and universal particle breakage occurs within the whole particle size range. The increasing of the cycle-index under cyclic simple shear test results in continuous compacting of the sample, so that the envelope curve of peak shearing force increases with the accumulated shear displacement.

Shear strength of non-shear reinforced concrete elements

DEFF Research Database (Denmark)

Hoang, Cao linh

1997-01-01

The paper deals with the plastic shear strength of non shear reinforced T-beams.The influence of an un-reinforced flange on the shear capacity is investigated by considering a failure mechanism involving crack sliding in the web and a kind of membrane action over an effective width of the flange...

Equivalence of two Fixed-Point Semantics for Definitional Higher-Order Logic Programs

Directory of Open Access Journals (Sweden)

Angelos Charalambidis

2015-09-01

Full Text Available Two distinct research approaches have been proposed for assigning a purely extensional semantics to higher-order logic programming. The former approach uses classical domain theoretic tools while the latter builds on a fixed-point construction defined on a syntactic instantiation of the source program. The relationships between these two approaches had not been investigated until now. In this paper we demonstrate that for a very broad class of programs, namely the class of definitional programs introduced by W. W. Wadge, the two approaches coincide (with respect to ground atoms that involve symbols of the program. On the other hand, we argue that if existential higher-order variables are allowed to appear in the bodies of program rules, the two approaches are in general different. The results of the paper contribute to a better understanding of the semantics of higher-order logic programming.

Geometrical optics in general relativity: A study of the higher order corrections

International Nuclear Information System (INIS)

Anile, A.M.

1976-01-01

The higher order corrections to geometrical optics are studied in general relativity for an electromagnetic test wave. An explicit expression is found for the average energy--momentum tensor which takes into account the first-order corrections. Finally the first-order corrections to the well-known area-intensity law of geometrical optics are derived

High shear stress relates to intraplaque haemorrhage in asymptomatic carotid plaques

DEFF Research Database (Denmark)

Tuenter, A.; Selwaness, M.; Arias Lorza, A.

2016-01-01

estimating equations analysis, adjusting for age, sex and carotid wall thickness. RESULTS: The study group consisted of 93 atherosclerotic carotid arteries of 74 participants. In plaques with higher maximum shear stresses, IPH was more often present (OR per unit increase in maximum shear stress (log......BACKGROUND AND AIMS: Carotid artery plaques with vulnerable plaque components are related to a higher risk of cerebrovascular accidents. It is unknown which factors drive vulnerable plaque development. Shear stress, the frictional force of blood at the vessel wall, is known to influence plaque...... formation. We evaluated the association between shear stress and plaque components (intraplaque haemorrhage (IPH), lipid rich necrotic core (LRNC) and/or calcifications) in relatively small carotid artery plaques in asymptomatic persons. METHODS: Participants (n = 74) from the population-based Rotterdam...

Contribution of higher order terms in the reductive perturbation theory, 2

International Nuclear Information System (INIS)

Ichikawa, Y.H.; Mitsuhashi, Teruo; Konno, Kimiaki.

1977-01-01

Contribution of higher order terms in the reductive perturbation theory has been investigated for nonlinear propagation of strongly dispersive ion plasma wave. The basic set of fluid equation is reduced to a coupled set of the nonlinear Schroedinger equation for the first order perturbed potential and a linear inhomogeneous equation for the second order perturbed potential. A steady state solution of the coupled set of equations has been solved analytically in the asymptotic limit of small wave number. (auth.)

Rheometry-PIV of shear-thickening wormlike micelles.

Science.gov (United States)

Marín-Santibañez, Benjamín M; Pérez-Gonzalez, José; de Vargas, Lourdes; Rodríguez-Gonzalez, Francisco; Huelsz, Guadalupe

2006-04-25

The shear-thickening behavior of an equimolar semidilute aqueous solution of 40 mM/L cetylpyridinium chloride and sodium salicylate was studied in this work by using a combined method of rheometry and particle image velocimetry (PIV). Experiments were conducted at 27.5 degrees C with Couette, vane-bob, and capillary rheometers in order to explore a wide shear stress range as well as the effect of boundary conditions and time of flow on the creation and destruction of shear-induced structures (SIS). The use of the combined method of capillary rheometry with PIV allowed the detection of fast spatial and temporal variations in the flow kinematics, which are related to the shear-thickening behavior and the dynamics of the SIS but are not distinguished by pure rheometrical measurements. A rich-in-details flow curve was found for this solution, which includes five different regimes. Namely, at very low shear rates a Newtonian behavior was found, followed by a shear thinning one in the second regime. In the third, shear banding was observed, which served as a precursor of the SIS and shear-thickening. The fourth and fifth regimes in the flow curve were separated by a spurtlike behavior, and they clearly evidenced the existence of shear-thickening accompanied by stick-slip oscillations at the wall of the rheometer, which subsequently produced variations in the shear rate under shear stress controlled flow. Such a stick-slip phenomenon prevailed up to the highest shear stresses used in this work and was reflected in asymmetric velocity profiles with spatial and temporal variations linked to the dynamics of creation and breakage of the SIS. The presence of apparent slip at the wall of the rheometer provides an energy release mechanism which leads to breakage of the SIS, followed by their further reformation during the stick part of the cycles. In addition, PIV measurements allowed the detection of apparent slip at the wall, as well as mechanical failures in the bulk of the

Laboratory investigation of nonlinear flow characteristics in rough fractures during shear process

Science.gov (United States)

Rong, Guan; Yang, Jie; Cheng, Long; Zhou, Chuangbing

2016-10-01

To understand the influence of shear behavior on the transporting properties of fluid through a single fracture, splitting fractures were made in the laboratory and shear flow tests were carried out under constant normal load conditions. The applied normal stress is in the range of 0.5-3.0 MPa. Before the physical test, the fracture's morphology is measured for identification of the roughness. At each shear step, we performed 5-8 high precise hydraulic tests with different hydraulic gradient. The relationship between pressure gradient and volume flow rate demonstrates to be nonlinear and fits very well with Forchheimer's and Izbash's laws. The linear and nonlinear coefficients in Forchheimer's law are quite sensitive to shear deformation (closure or dilation), experienced 1-2 and 1-3 orders of magnitude reduction during shear, respectively. An empirical equation is proposed to quantify the relationship between linear coefficient and nonlinear coefficient based on the experimental observations. The two coefficients in Izbash's law are quantified. The m value is in the range between 1.06 and 1.41 and the λ value experiences a reduction of 1-2 orders of magnitude during shear. In addition, the studied critical Reynolds number exhibits a decreasing and increasing variation corresponding to shear contraction and shear dilation of rock fracture. For all the cases in this study, the critical Reynolds number ranges between 1.5 and 13.0.

Significance of Shear Wall in Multi-Storey Structure With Seismic Analysis

Science.gov (United States)

Bongilwar, Rajat; Harne, V. R.; Chopade, Aditya

2018-03-01

In past decades, shear walls are one of the most appropriate and important structural component in multi-storied building. Therefore, it would be very interesting to study the structural response and their systems in multi-storied structure. Shear walls contribute the stiffness and strength during earthquakes which are often neglected during design of structure and construction. This study shows the effect of shear walls which significantly affect the vulnerability of structures. In order to test this hypothesis, G+8 storey building was considered with and without shear walls and analyzed for various parameters like base shear, storey drift ratio, lateral displacement, bending moment and shear force. Significance of shear wall has been studied with the help of two models. First model is without shear wall i.e. bare frame and other another model is with shear wall considering opening also in it. For modeling and analysis of both the models, FEM based software ETABS 2016 were used. The analysis of all models was done using Equivalent static method. The comparison of results has been done based on same parameters like base shear, storey drift ratio, lateral displacement, bending moment and shear force.

Oscillation of certain higher-order neutral partial functional differential equations.

Science.gov (United States)

Li, Wei Nian; Sheng, Weihong

2016-01-01

In this paper, we study the oscillation of certain higher-order neutral partial functional differential equations with the Robin boundary conditions. Some oscillation criteria are established. Two examples are given to illustrate the main results in the end of this paper.

Numerical methods of higher order of accuracy for incompressible flows

Czech Academy of Sciences Publication Activity Database

Kozel, K.; Louda, Petr; Příhoda, Jaromír

2010-01-01

Roč. 80, č. 8 (2010), s. 1734-1745 ISSN 0378-4754 Institutional research plan: CEZ:AV0Z20760514 Keywords : higher order methods * upwind methods * backward-facing step Subject RIV: BK - Fluid Dynamics Impact factor: 0.812, year: 2010

Evidence for higher-order effects in L-shell ionization by proton impact

International Nuclear Information System (INIS)

Sarkadi, L.; Mukoyama, T.

1988-01-01

It is widely believed that higher order processes of ion-atom collisions are negligible in cases of light projectiles like proton. Recent refined experiments tried to prove that the existence of such effects were comperable with the experimental errors, and they showed the unexpected relative importance of the higher order processes. Thus a new coupled channel calculation was performed for proton-gold atom collision in the energy range of 0.15-3.0 MeV, including dynamical subshell coupling effects. The results show that the deviations from the first order cross sections reach 40% at low collision energy. This result made necessary to correct the calculations of L-shell X-ray production cross sections. (D.G.) 6 refs

SHEAR ACCELERATION IN EXPANDING FLOWS

Energy Technology Data Exchange (ETDEWEB)

Rieger, F. M. [ZAH, Institut für Theoretische Astrophysik, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Duffy, P., E-mail: frank.rieger@mpi-hd.mpg.de, E-mail: peter.duffy@ucd.ie [University College Dublin, Belfield, Dublin 4 (Ireland)

2016-12-10

Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate the acceleration of energetic charged particles to higher energies. To this end, the gradual shear acceleration coefficient is derived based on an analytical treatment. The results are applied to the context of the relativistic jets from active galactic nuclei. The inferred acceleration timescale is investigated for a variety of conical flow profiles (i.e., power law, Gaussian, Fermi–Dirac) and compared to the relevant radiative and non-radiative loss timescales. The results exemplify that relativistic shear flows are capable of boosting cosmic-rays to extreme energies. Efficient electron acceleration, on the other hand, requires weak magnetic fields and may thus be accompanied by a delayed onset of particle energization and affect the overall jet appearance (e.g., core, ridge line, and limb-brightening).

Cosmic shear measurement with maximum likelihood and maximum a posteriori inference

Science.gov (United States)

Hall, Alex; Taylor, Andy

2017-06-01

We investigate the problem of noise bias in maximum likelihood and maximum a posteriori estimators for cosmic shear. We derive the leading and next-to-leading order biases and compute them in the context of galaxy ellipticity measurements, extending previous work on maximum likelihood inference for weak lensing. We show that a large part of the bias on these point estimators can be removed using information already contained in the likelihood when a galaxy model is specified, without the need for external calibration. We test these bias-corrected estimators on simulated galaxy images similar to those expected from planned space-based weak lensing surveys, with promising results. We find that the introduction of an intrinsic shape prior can help with mitigation of noise bias, such that the maximum a posteriori estimate can be made less biased than the maximum likelihood estimate. Second-order terms offer a check on the convergence of the estimators, but are largely subdominant. We show how biases propagate to shear estimates, demonstrating in our simple set-up that shear biases can be reduced by orders of magnitude and potentially to within the requirements of planned space-based surveys at mild signal-to-noise ratio. We find that second-order terms can exhibit significant cancellations at low signal-to-noise ratio when Gaussian noise is assumed, which has implications for inferring the performance of shear-measurement algorithms from simplified simulations. We discuss the viability of our point estimators as tools for lensing inference, arguing that they allow for the robust measurement of ellipticity and shear.

Practical Programming with Higher-Order Encodings and Dependent Types

DEFF Research Database (Denmark)

Poswolsky, Adam; Schürmann, Carsten

2008-01-01

, tedious, and error-prone. In this paper, we describe the underlying calculus of Delphin. Delphin is a fully implemented functional-programming language supporting reasoning over higher-order encodings and dependent types, while maintaining the benefits of HOAS. More specifically, just as representations...... for instantiation from those that will remain uninstantiated, utilizing a variation of Miller and Tiu’s ∇-quantifier [1]....

Symmetries, invariants and generating functions: higher-order statistics of biased tracers

Science.gov (United States)

Munshi, Dipak

2018-01-01

Gravitationally collapsed objects are known to be biased tracers of an underlying density contrast. Using symmetry arguments, generalised biasing schemes have recently been developed to relate the halo density contrast δh with the underlying density contrast δ, divergence of velocity θ and their higher-order derivatives. This is done by constructing invariants such as s, t, ψ,η. We show how the generating function formalism in Eulerian standard perturbation theory (SPT) can be used to show that many of the additional terms based on extended Galilean and Lifshitz symmetry actually do not make any contribution to the higher-order statistics of biased tracers. Other terms can also be drastically simplified allowing us to write the vertices associated with δh in terms of the vertices of δ and θ, the higher-order derivatives and the bias coefficients. We also compute the cumulant correlators (CCs) for two different tracer populations. These perturbative results are valid for tree-level contributions but at an arbitrary order. We also take into account the stochastic nature bias in our analysis. Extending previous results of a local polynomial model of bias, we express the one-point cumulants Script SN and their two-point counterparts, the CCs i.e. Script Cpq, of biased tracers in terms of that of their underlying density contrast counterparts. As a by-product of our calculation we also discuss the results using approximations based on Lagrangian perturbation theory (LPT).

Shear viscosity and out of equilibrium dynamics

International Nuclear Information System (INIS)

El, Andrej; Xu Zhe; Greiner, Carsten; Muronga, Azwinndini

2009-01-01

Using Grad's method, we calculate the entropy production and derive a formula for the second-order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance, the shear tensor and the shear viscosity to entropy density ratio η/s are numerically calculated by an iterative and self-consistent prescription within the second-order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with η/s obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling α s ∼0.3 (with η/s≅0.18) and is a factor of 2-3 larger at a small coupling α s ∼0.01. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on η/s, except when employing a small α s . On the other hand, we demonstrate that for such small α s , the gluon system is far from kinetic and chemical equilibrium, which indicates the break down of second-order hydrodynamics because of the strong nonequilibrium evolution. In addition, for large α s (0.3-0.6), the Israel-Stewart hydrodynamics formally breaks down at large momentum p T > or approx. 3 GeV but is still a reasonably good approximation.

Modeling 3D PCMI using the Extended Finite Element Method with higher order elements

Energy Technology Data Exchange (ETDEWEB)

Jiang, W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spencer, Benjamin W. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2017-03-31

This report documents the recent development to enable XFEM to work with higher order elements. It also demonstrates the application of higher order (quadratic) elements to both 2D and 3D models of PCMI problems, where discrete fractures in the fuel are represented using XFEM. The modeling results demonstrate the ability of the higher order XFEM to accurately capture the effects of a crack on the response in the vicinity of the intersecting surfaces of cracked fuel and cladding, as well as represent smooth responses in the regions away from the crack.

A higher-order tensor vessel tractography for segmentation of vascular structures.

Science.gov (United States)

Cetin, Suheyla; Unal, Gozde

2015-10-01

A new vascular structure segmentation method, which is based on a cylindrical flux-based higher order tensor (HOT), is presented. On a vessel structure, the HOT naturally models branching points, which create challenges for vessel segmentation algorithms. In a general linear HOT model embedded in 3D, one has to work with an even order tensor due to an enforced antipodal-symmetry on the unit sphere. However, in scenarios such as in a bifurcation, the antipodally-symmetric tensor embedded in 3D will not be useful. In order to overcome that limitation, we embed the tensor in 4D and obtain a structure that can model asymmetric junction scenarios. During construction of a higher order tensor (e.g. third or fourth order) in 4D, the orientation vectors lie on the unit 3-sphere, in contrast to the unit 2-sphere in 3D tensor modeling. This 4D tensor is exploited in a seed-based vessel segmentation algorithm, where the principal directions of the 4D HOT is obtained by decomposition, and used in a HOT tractography approach. We demonstrate quantitative validation of the proposed algorithm on both synthetic complex tubular structures as well as real cerebral vasculature in Magnetic Resonance Angiography (MRA) datasets and coronary arteries from Computed Tomography Angiography (CTA) volumes.

Construction of special eye models for investigation of chromatic and higher-order aberrations of eyes.

Science.gov (United States)

Zhai, Yi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; He, Yuanqing; Chang, Shengjiang

2014-01-01

An achromatic element eliminating only longitudinal chromatic aberration (LCA) while maintaining transverse chromatic aberration (TCA) is established for the eye model, which involves the angle formed by the visual and optical axis. To investigate the impacts of higher-order aberrations on vision, the actual data of higher-order aberrations of human eyes with three typical levels are introduced into the eye model along visual axis. Moreover, three kinds of individual eye models are established to investigate the impacts of higher-order aberrations, chromatic aberration (LCA+TCA), LCA and TCA on vision under the photopic condition, respectively. Results show that for most human eyes, the impact of chromatic aberration on vision is much stronger than that of higher-order aberrations, and the impact of LCA in chromatic aberration dominates. The impact of TCA is approximately equal to that of normal level higher-order aberrations and it can be ignored when LCA exists.

Collocated electrodynamic FDTD schemes using overlapping Yee grids and higher-order Hodge duals

Science.gov (United States)

Deimert, C.; Potter, M. E.; Okoniewski, M.

2016-12-01

The collocated Lebedev grid has previously been proposed as an alternative to the Yee grid for electromagnetic finite-difference time-domain (FDTD) simulations. While it performs better in anisotropic media, it performs poorly in isotropic media because it is equivalent to four overlapping, uncoupled Yee grids. We propose to couple the four Yee grids and fix the Lebedev method using discrete exterior calculus (DEC) with higher-order Hodge duals. We find that higher-order Hodge duals do improve the performance of the Lebedev grid, but they also improve the Yee grid by a similar amount. The effectiveness of coupling overlapping Yee grids with a higher-order Hodge dual is thus questionable. However, the theoretical foundations developed to derive these methods may be of interest in other problems.

ANOVA-HDMR structure of the higher order nodal diffusion solution

International Nuclear Information System (INIS)

Bokov, P. M.; Prinsloo, R. H.; Tomasevic, D. I.

2013-01-01

Nodal diffusion methods still represent a standard in global reactor calculations, but employ some ad-hoc approximations (such as the quadratic leakage approximation) which limit their accuracy in cases where reference quality solutions are sought. In this work we solve the nodal diffusion equations utilizing the so-called higher-order nodal methods to generate reference quality solutions and to decompose the obtained solutions via a technique known as High Dimensional Model Representation (HDMR). This representation and associated decomposition of the solution provides a new formulation of the transverse leakage term. The HDMR structure is investigated via the technique of Analysis of Variance (ANOVA), which indicates why the existing class of transversely-integrated nodal methods prove to be so successful. Furthermore, the analysis leads to a potential solution method for generating reference quality solutions at a much reduced calculational cost, by applying the ANOVA technique to the full higher order solution. (authors)

Swimming efficiency in a shear-thinning fluid

Science.gov (United States)

Nganguia, Herve; Pietrzyk, Kyle; Pak, On Shun

2017-12-01

Micro-organisms expend energy moving through complex media. While propulsion speed is an important property of locomotion, efficiency is another factor that may determine the swimming gait adopted by a micro-organism in order to locomote in an energetically favorable manner. The efficiency of swimming in a Newtonian fluid is well characterized for different biological and artificial swimmers. However, these swimmers often encounter biological fluids displaying shear-thinning viscosities. Little is known about how this nonlinear rheology influences the efficiency of locomotion. Does the shear-thinning rheology render swimming more efficient or less? How does the swimming efficiency depend on the propulsion mechanism of a swimmer and rheological properties of the surrounding shear-thinning fluid? In this work, we address these fundamental questions on the efficiency of locomotion in a shear-thinning fluid by considering the squirmer model as a general locomotion model to represent different types of swimmers. Our analysis reveals how the choice of surface velocity distribution on a squirmer may reduce or enhance the swimming efficiency. We determine optimal shear rates at which the swimming efficiency can be substantially enhanced compared with the Newtonian case. The nontrivial variations of swimming efficiency prompt questions on how micro-organisms may tune their swimming gaits to exploit the shear-thinning rheology. The findings also provide insights into how artificial swimmers should be designed to move through complex media efficiently.

Time-discrete higher order ALE formulations: a priori error analysis

KAUST Repository

Bonito, Andrea

2013-03-16

We derive optimal a priori error estimates for discontinuous Galerkin (dG) time discrete schemes of any order applied to an advection-diffusion model defined on moving domains and written in the Arbitrary Lagrangian Eulerian (ALE) framework. Our estimates hold without any restrictions on the time steps for dG with exact integration or Reynolds\\' quadrature. They involve a mild restriction on the time steps for the practical Runge-Kutta-Radau methods of any order. The key ingredients are the stability results shown earlier in Bonito et al. (Time-discrete higher order ALE formulations: stability, 2013) along with a novel ALE projection. Numerical experiments illustrate and complement our theoretical results. © 2013 Springer-Verlag Berlin Heidelberg.

Higher-Order Statistical Correlations and Mutual Information Among Particles in a Quantum Well

Science.gov (United States)

Yépez, V. S.; Sagar, R. P.; Laguna, H. G.

2017-12-01

The influence of wave function symmetry on statistical correlation is studied for the case of three non-interacting spin-free quantum particles in a unidimensional box, in position and in momentum space. Higher-order statistical correlations occurring among the three particles in this quantum system is quantified via higher-order mutual information and compared to the correlation between pairs of variables in this model, and to the correlation in the two-particle system. The results for the higher-order mutual information show that there are states where the symmetric wave functions are more correlated than the antisymmetric ones with same quantum numbers. This holds in position as well as in momentum space. This behavior is opposite to that observed for the correlation between pairs of variables in this model, and the two-particle system, where the antisymmetric wave functions are in general more correlated. These results are also consistent with those observed in a system of three uncoupled oscillators. The use of higher-order mutual information as a correlation measure, is monitored and examined by considering a superposition of states or systems with two Slater determinants.

Higher-Order Statistical Correlations and Mutual Information Among Particles in a Quantum Well

International Nuclear Information System (INIS)

Yépez, V. S.; Sagar, R. P.; Laguna, H. G.

2017-01-01

The influence of wave function symmetry on statistical correlation is studied for the case of three non-interacting spin-free quantum particles in a unidimensional box, in position and in momentum space. Higher-order statistical correlations occurring among the three particles in this quantum system is quantified via higher-order mutual information and compared to the correlation between pairs of variables in this model, and to the correlation in the two-particle system. The results for the higher-order mutual information show that there are states where the symmetric wave functions are more correlated than the antisymmetric ones with same quantum numbers. This holds in position as well as in momentum space. This behavior is opposite to that observed for the correlation between pairs of variables in this model, and the two-particle system, where the antisymmetric wave functions are in general more correlated. These results are also consistent with those observed in a system of three uncoupled oscillators. The use of higher-order mutual information as a correlation measure, is monitored and examined by considering a superposition of states or systems with two Slater determinants. (author)

Higher-order Brunnian structures and possible physical realizations

DEFF Research Database (Denmark)

A. Baas, Nils; V. Fedorov, D.; S. Jensen, A.

2014-01-01

We consider few-body bound state systems and provide precise definitions of Borromean and Brunnian systems. The initial concepts are more than a hundred years old and originated in mathematical knot-theory as purely geometric considerations. About thirty years ago they were generalized and applied...... to the binding of systems in nature. It now appears that recent generalization to higher order Brunnian structures may potentially be realized as laboratory made or naturally occurring systems. With the binding energy as measure, we discuss possibilities of physical realization in nuclei, cold atoms...

Integrable higher order deformations of Heisenberg supermagnetic model

International Nuclear Information System (INIS)

Guo Jiafeng; Yan Zhaowen; Wang Shikun; Wu Ke; Zhao Weizhong

2009-01-01

The Heisenberg supermagnet model is an integrable supersymmetric system and has a close relationship with the strong electron correlated Hubbard model. In this paper, we investigate the integrable higher order deformations of Heisenberg supermagnet models with two different constraints: (i) S 2 =3S-2I for S is an element of USPL(2/1)/S(U(2)xU(1)) and (ii) S 2 =S for S is an element of USPL(2/1)/S(L(1/1)xU(1)). In terms of the gauge transformation, their corresponding gauge equivalent counterparts are derived.

Theory of a higher-order Sturm-Liouville equation

CERN Document Server

Kozlov, Vladimir

1997-01-01

This book develops a detailed theory of a generalized Sturm-Liouville Equation, which includes conditions of solvability, classes of uniqueness, positivity properties of solutions and Green's functions, asymptotic properties of solutions at infinity. Of independent interest, the higher-order Sturm-Liouville equation also proved to have important applications to differential equations with operator coefficients and elliptic boundary value problems for domains with non-smooth boundaries. The book addresses graduate students and researchers in ordinary and partial differential equations, and is accessible with a standard undergraduate course in real analysis.

Programming real-time executives in higher order language

Science.gov (United States)

Foudriat, E. C.

1982-01-01

Methods by which real-time executive programs can be implemented in a higher order language are discussed, using HAL/S and Path Pascal languages as program examples. Techniques are presented by which noncyclic tasks can readily be incorporated into the executive system. Situations are shown where the executive system can fail to meet its task scheduling and yet be able to recover either by rephasing the clock or stacking the information for later processing. The concept of deadline processing is shown to enable more effective mixing of time and information synchronized systems.

Higher order Bose-Einstein correlations in identical particle production

International Nuclear Information System (INIS)

Biyajima, M.

1990-01-01

A diagram technique to calculate the higher order Bose-Einstein correlations is formulated. This technique is applied to derive explicit expressions for the n-pion correlation functions for n = 2, 3, 4, and 5, and numerical predictions are given. In a comparison with the AFS and NA23 data on two-pion and three-pion Bose-Einstein correlations good agreement is obtained. 21 refs., 5 figs. (Authors)

Solution of volume-surface integral equations using higher-order hierarchical Legendre basis functions

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Meincke, Peter; Breinbjerg, Olav

2007-01-01

The problem of electromagnetic scattering by composite metallic and dielectric objects is solved using the coupled volume-surface integral equation (VSIE). The method of moments (MoM) based on higher-order hierarchical Legendre basis functions and higher-order curvilinear geometrical elements...... with the analytical Mie series solution. Scattering by more complex metal-dielectric objects are also considered to compare the presented technique with other numerical methods....

Interaction of equal-size bubbles in shear flow.

Science.gov (United States)

Prakash, Jai; Lavrenteva, Olga M; Byk, Leonid; Nir, Avinoam

2013-04-01

The inertia-induced forces on two identical spherical bubbles in a simple shear flow at small but finite Reynolds number, for the case when the bubbles are within each other's inner viscous region, are calculated making use of the reciprocal theorem. This interaction force is further employed to model the dynamics of air bubbles injected to a viscous fluid sheared in a Couette device at the first shear flow instability where the bubbles are trapped inside the stable Taylor vortex. It was shown that, during a long time scale, the inertial interaction between the bubbles in the primary shear flow drives them away from each other and, as a result, equal-size bubbles eventually assume an ordered string with equal separation distances between all neighbors. We report on experiments showing the dynamic evolution of various numbers of bubbles. The results of the theory are in good agreement with the experimental observations.

Higher-order Bessel like beams with z-dependent cone angles

CSIR Research Space (South Africa)

Ismail, Y

2010-08-01

Full Text Available .64.81.22. Terms of Use: http://spiedl.org/terms Fig.5: Optical design to generate z-dependent Bessel-like beams 4. CONSIDERING A MATHEMATICAL APPROACH TO EXPLAINING Z-DEPENDENT BLB?S The stationary phase method is implemented in order to confirm... on higher-order z-dependent BLB?s [6]. 5. EXPERIMENTALLY GENERATED Z-DEPENDENT BESSEL-LIKE BEAMS From the above in can be deduced that these beams are Bessel-like hence they are so named z-dependent Bessel-like beams. These beams are produced however...

Fractional equivalent Lagrangian densities for a fractional higher-order equation

International Nuclear Information System (INIS)

Fujioka, J

2014-01-01

In this communication we show that the equivalent Lagrangian densities (ELDs) of a fractional higher-order nonlinear Schrödinger equation with stable soliton-like solutions can be related in a hitherto unknown way. This new relationship is described in terms of a new fractional operator that includes both left- and right-sided fractional derivatives. Using this operator it is possible to generate new ELDs that contain different fractional parts, in addition to the already known ELDs, which only differ by a sum of first-order partial derivatives of two arbitrary functions. (fast track communications)

Higher-order radiative corrections for b b ¯→H-W+

Science.gov (United States)

Kidonakis, Nikolaos

2018-02-01

I present higher-order radiative corrections from collinear and soft-gluon emission for the associated production of a charged Higgs boson with a W boson. The calculation uses expressions from resummation at next-to-leading-logarithm accuracy. From the resummed cross section I derive analytical formulas at approximate next-to-next-to-leading order and next-to-next-to-next-to-leading order. Total cross sections are presented for the process b b ¯→H-W+ at various LHC energies. The transverse momentum and rapidity distributions of the charged Higgs boson are also calculated.

Higher-order schemes for the Laplace transformation method for parabolic problems

KAUST Repository

Douglas, C.

2011-01-01

In this paper we solve linear parabolic problems using the three stage noble algorithms. First, the time discretization is approximated using the Laplace transformation method, which is both parallel in time (and can be in space, too) and extremely high order convergent. Second, higher-order compact schemes of order four and six are used for the the spatial discretization. Finally, the discretized linear algebraic systems are solved using multigrid to show the actual convergence rate for numerical examples, which are compared to other numerical solution methods. © 2011 Springer-Verlag.

Foundational (co)datatypes and (co)recursion for higher-order logic

NARCIS (Netherlands)

Biendarra, Julian; Blanchette, Jasmin Christian; Bouzy, Aymeric; Desharnais, Martin; Fleury, Mathias; Hölzl, Johannes; Kunčar, Ondřej; Lochbihler, Andreas; Meier, Fabian; Panny, Lorenz; Popescu, Andrei; Sternagel, Christian; Thiemann, René; Traytel, Dmitriy; Dixon, C.; Finger, M.

2017-01-01

We describe a line of work that started in 2011 towards enriching Isabelle/HOL’s language with coinductive datatypes, which allow infinite values, and with a more expressive notion of inductive datatype than previously supported by any system based on higher-order logic. These (co)datatypes are

Superpositions of higher-order bessel beams and nondiffracting speckle fields

CSIR Research Space (South Africa)

Dudley, Angela L

2009-08-01

Full Text Available speckle fields. The paper reports on illuminating a ring slit aperture with light which has an azimuthal phase dependence, such that the field produced is a superposition of two higher-order Bessel beams. In the case that the phase dependence of the light...

Authentic Instruction for 21st Century Learning: Higher Order Thinking in an Inclusive School

Science.gov (United States)

Preus, Betty

2012-01-01

The author studied a public junior high school identified as successfully implementing authentic instruction. Such instruction emphasizes higher order thinking, deep knowledge, substantive conversation, and value beyond school. To determine in what ways higher order thinking was fostered both for students with and without disabilities, the author…

Resilience and Higher Order Thinking

Directory of Open Access Journals (Sweden)

Ioan Fazey

2010-09-01

Full Text Available To appreciate, understand, and tackle chronic global social and environmental problems, greater appreciation of the importance of higher order thinking is required. Such thinking includes personal epistemological beliefs (PEBs, i.e., the beliefs people hold about the nature of knowledge and how something is known. These beliefs have profound implications for the way individuals relate to each other and the world, such as how people understand complex social-ecological systems. Resilience thinking is an approach to environmental stewardship that includes a number of interrelated concepts and has strong foundations in systemic ways of thinking. This paper (1 summarizes a review of educational psychology literature on PEBs, (2 explains why resilience thinking has potential to facilitate development of more sophisticated PEBs, (3 describes an example of a module designed to teach resilience thinking to undergraduate students in ways conducive to influencing PEBs, and (4 discusses a pilot study that evaluates the module's impact. Theoretical and preliminary evidence from the pilot evaluation suggests that resilience thinking which is underpinned by systems thinking has considerable potential to influence the development of more sophisticated PEBs. To be effective, however, careful consideration of how resilience thinking is taught is required. Finding ways to encourage students to take greater responsibility for their own learning and ensuring close alignment between assessment and desired learning outcomes are particularly important.

Robust rooftop extraction from visible band images using higher order CRF

KAUST Repository

Li, Er

2015-08-01

In this paper, we propose a robust framework for building extraction in visible band images. We first get an initial classification of the pixels based on an unsupervised presegmentation. Then, we develop a novel conditional random field (CRF) formulation to achieve accurate rooftops extraction, which incorporates pixel-level information and segment-level information for the identification of rooftops. Comparing with the commonly used CRF model, a higher order potential defined on segment is added in our model, by exploiting region consistency and shape feature at segment level. Our experiments show that the proposed higher order CRF model outperforms the state-of-the-art methods both at pixel and object levels on rooftops with complex structures and sizes in challenging environments. © 1980-2012 IEEE.

Higher-order meshing of implicit geometries, Part II: Approximations on manifolds

Science.gov (United States)

Fries, T. P.; Schöllhammer, D.

2017-11-01

A new concept for the higher-order accurate approximation of partial differential equations on manifolds is proposed where a surface mesh composed by higher-order elements is automatically generated based on level-set data. Thereby, it enables a completely automatic workflow from the geometric description to the numerical analysis without any user-intervention. A master level-set function defines the shape of the manifold through its zero-isosurface which is then restricted to a finite domain by additional level-set functions. It is ensured that the surface elements are sufficiently continuous and shape regular which is achieved by manipulating the background mesh. The numerical results show that optimal convergence rates are obtained with a moderate increase in the condition number compared to handcrafted surface meshes.

Security Analysis of 7-Round MISTY1 against Higher Order Differential Attacks

Science.gov (United States)

Tsunoo, Yukiyasu; Saito, Teruo; Shigeri, Maki; Kawabata, Takeshi

MISTY1 is a 64-bit block cipher that has provable security against differential and linear cryptanalysis. MISTY1 is one of the algorithms selected in the European NESSIE project, and it has been recommended for Japanese e-Government ciphers by the CRYPTREC project. This paper shows that higher order differential attacks can be successful against 7-round versions of MISTY1 with FL functions. The attack on 7-round MISTY1 can recover a partial subkey with a data complexity of 254.1 and a computational complexity of 2120.8, which signifies the first successful attack on 7-round MISTY1 with no limitation such as a weak key. This paper also evaluates the complexity of this higher order differential attack on MISTY1 in which the key schedule is replaced by a pseudorandom function. It is shown that resistance to the higher order differential attack is not substantially improved even in 7-round MISTY1 in which the key schedule is replaced by a pseudorandom function.

A new method to study simple shear processing of wheat gluten-starch mixtures

NARCIS (Netherlands)

Peighambardoust, S.H.; Goot, A.J. van der; Hamer, R.J.; Boom, R.M.

2004-01-01

This article introduces a new method that uses a shearing device to study the effect of simple shear on the overall properties of pasta-like products made from commercial wheat gluten-starch (GS) blends. The shear-processed GS samples had a lower cooking loss (CL) and a higher swelling index (SI)

A higher order space-time Galerkin scheme for time domain integral equations

KAUST Repository

Pray, Andrew J.

2014-12-01

Stability of time domain integral equation (TDIE) solvers has remained an elusive goal formany years. Advancement of this research has largely progressed on four fronts: 1) Exact integration, 2) Lubich quadrature, 3) smooth temporal basis functions, and 4) space-time separation of convolutions with the retarded potential. The latter method\\'s efficacy in stabilizing solutions to the time domain electric field integral equation (TD-EFIE) was previously reported for first-order surface descriptions (flat elements) and zeroth-order functions as the temporal basis. In this work, we develop the methodology necessary to extend the scheme to higher order surface descriptions as well as to enable its use with higher order basis functions in both space and time. These basis functions are then used in a space-time Galerkin framework. A number of results are presented that demonstrate convergence in time. The viability of the space-time separation method in producing stable results is demonstrated experimentally for these examples.

A higher order space-time Galerkin scheme for time domain integral equations

KAUST Repository

Pray, Andrew J.; Beghein, Yves; Nair, Naveen V.; Cools, Kristof; Bagci, Hakan; Shanker, Balasubramaniam

2014-01-01

Stability of time domain integral equation (TDIE) solvers has remained an elusive goal formany years. Advancement of this research has largely progressed on four fronts: 1) Exact integration, 2) Lubich quadrature, 3) smooth temporal basis functions, and 4) space-time separation of convolutions with the retarded potential. The latter method's efficacy in stabilizing solutions to the time domain electric field integral equation (TD-EFIE) was previously reported for first-order surface descriptions (flat elements) and zeroth-order functions as the temporal basis. In this work, we develop the methodology necessary to extend the scheme to higher order surface descriptions as well as to enable its use with higher order basis functions in both space and time. These basis functions are then used in a space-time Galerkin framework. A number of results are presented that demonstrate convergence in time. The viability of the space-time separation method in producing stable results is demonstrated experimentally for these examples.

An Investigation of Higher-Order Thinking Skills in Smaller Learning Community Social Studies Classrooms

Science.gov (United States)

Fischer, Christopher; Bol, Linda; Pribesh, Shana

2011-01-01

This study investigated the extent to which higher-order thinking skills are promoted in social studies classes in high schools that are implementing smaller learning communities (SLCs). Data collection in this mixed-methods study included classroom observations and in-depth interviews. Findings indicated that higher-order thinking was rarely…

Three-Dimensional Geostatistical Analysis of Rock Fracture Roughness and Its Degradation with Shearing

Directory of Open Access Journals (Sweden)

Nima Babanouri

2013-12-01

Full Text Available Three-dimensional surface geometry of rock discontinuities and its evolution with shearing are of great importance in understanding the deformability and hydro-mechanical behavior of rock masses. In the present research, surfaces of three natural rock fractures were digitized and studied before and after the direct shear test. The variography analysis of the surfaces indicated a strong non-linear trend in the data. Therefore, the spatial variability of rock fracture surfaces was decomposed to one deterministic component characterized by a base polynomial function, and one stochastic component described by the variogram of residuals. By using an image-processing technique, 343 damaged zones with different sizes, shapes, initial roughness characteristics, local stress fields, and asperity strength values were spatially located and clustered. In order to characterize the overall spatial structure of the degraded zones, the concept of ‘pseudo-zonal variogram’ was introduced. The results showed that the spatial continuity at the damage locations increased due to asperity degradation. The increase in the variogram range was anisotropic and tended to be higher in the shear direction; thus, the direction of maximum continuity rotated towards the shear direction. Finally, the regression-kriging method was used to reconstruct the morphology of the intact surfaces and degraded areas. The cross-validation error of interpolation for the damaged zones was found smaller than that obtained for the intact surface.

Toward an Understanding of Higher-Order Thinking among Minority Students.

Science.gov (United States)

Armour-Thomas, Eleanor; And Others

1992-01-01

Used principal-factors extraction with varimax rotation analysis to clarify nature and function of higher-order thinking among minority high school students (n=107) from economically disadvantaged backgrounds. Results allowed for specification of mental processes associated with the construct and the extent to which students reported awareness and…

Sleep inertia, sleep homeostatic and circadian influences on higher-order cognitive functions.

Science.gov (United States)

Burke, Tina M; Scheer, Frank A J L; Ronda, Joseph M; Czeisler, Charles A; Wright, Kenneth P

2015-08-01

Sleep inertia, sleep homeostatic and circadian processes modulate cognition, including reaction time, memory, mood and alertness. How these processes influence higher-order cognitive functions is not well known. Six participants completed a 73-day-long study that included two 14-day-long 28-h forced desynchrony protocols to examine separate and interacting influences of sleep inertia, sleep homeostasis and circadian phase on higher-order cognitive functions of inhibitory control and selective visual attention. Cognitive performance for most measures was impaired immediately after scheduled awakening and improved during the first ~2-4 h of wakefulness (decreasing sleep inertia); worsened thereafter until scheduled bedtime (increasing sleep homeostasis); and was worst at ~60° and best at ~240° (circadian modulation, with worst and best phases corresponding to ~09:00 and ~21:00 hours, respectively, in individuals with a habitual wake time of 07:00 hours). The relative influences of sleep inertia, sleep homeostasis and circadian phase depended on the specific higher-order cognitive function task examined. Inhibitory control appeared to be modulated most strongly by circadian phase, whereas selective visual attention for a spatial-configuration search task was modulated most strongly by sleep inertia. These findings demonstrate that some higher-order cognitive processes are differentially sensitive to different sleep-wake regulatory processes. Differential modulation of cognitive functions by different sleep-wake regulatory processes has important implications for understanding mechanisms contributing to performance impairments during adverse circadian phases, sleep deprivation and/or upon awakening from sleep. © 2015 European Sleep Research Society.

On higher-order corrections in M theory

International Nuclear Information System (INIS)

Howe, P.S.; Tsimpis, D.

2003-01-01

A theoretical analysis of higher-order corrections to D=11 supergravity is given in a superspace framework. It is shown that any deformation of D=11 supergravity for which the lowest-dimensional component of the four-form G 4 vanishes is trivial. This implies that the equations of motion of D=11 supergravity are specified by an element of a certain spinorial cohomology group and generalises previous results obtained using spinorial or pure spinor cohomology to the fully non-linear theory. The first deformation of the theory is given by an element of a different spinorial cohomology group with coefficients which are local tensorial functions of the massless supergravity fields. The four-form Bianchi Identities are solved, to first order and at dimension -{1/2}, in the case that the lowest-dimensional component of G 4 is non-zero. Moreover, it is shown how one can calculate the first-order correction to the dimension-zero torsion and thus to the supergravity equations of motion given an explicit expression for this object in terms of the supergravity fields. The version of the theory with both a four-form and a seven-form is discussed in the presence of the five-brane anomaly-cancelling term. It is shown that the supersymmetric completion of this term exists and it is argued that it is the unique anomaly-cancelling invariant at this dimension which is at least quartic in the fields. This implies that the first deformation of the theory is completely determined by the anomaly term from which one can, in principle, read off the corrections to all of the superspace field strength tensors. (author)

Higher-Order Wavefront Aberrations for Populations of Young Emmetropes and Myopes

Directory of Open Access Journals (Sweden)

Jinhua Bao

2009-01-01

Conclusions: Human eyes have systematical higher order aberrations in population, and factors that cause bilateral symmetry of wavefront aberrations between the right and left eyes made important contribution to the systematical aberrations.

A stable higher order space time Galerkin marching-on-in-time scheme

KAUST Repository

Pray, Andrew J.

2013-07-01

We present a method for the stable solution of time-domain integral equations. The method uses a technique developed in [1] to accurately evaluate matrix elements. As opposed to existing stabilization schemes, the method presented uses higher order basis functions in time to improve the accuracy of the solver. The method is validated by showing convergence in temporal basis function order, time step size, and geometric discretization order. © 2013 IEEE.

A Content Analysis of General Chemistry Laboratory Manuals for Evidence of Higher-Order Cognitive Tasks

Science.gov (United States)

Domin, Daniel S.

1999-01-01

The science laboratory instructional environment is ideal for fostering the development of problem-solving, manipulative, and higher-order thinking skills: the skills needed by today's learner to compete in an ever increasing technology-based society. This paper reports the results of a content analysis of ten general chemistry laboratory manuals. Three experiments from each manual were examined for evidence of higher-order cognitive activities. Analysis was based upon the six major cognitive categories of Bloom's Taxonomy of Educational Objectives: knowledge, comprehension, application, analysis, synthesis, and evaluation. The results of this study show that the overwhelming majority of general chemistry laboratory manuals provide tasks that require the use of only the lower-order cognitive skills: knowledge, comprehension, and application. Two of the laboratory manuals were disparate in having activities that utilized higher-order cognition. I describe the instructional strategies used within these manuals to foster higher-order cognitive development.

An in silico framework to analyze the anisotropic shear wave mechanics in cardiac shear wave elastography

Science.gov (United States)

Caenen, Annette; Pernot, Mathieu; Peirlinck, Mathias; Mertens, Luc; Swillens, Abigail; Segers, Patrick

2018-04-01

Shear wave elastography (SWE) is a potential tool to non-invasively assess cardiac muscle stiffness. This study focused on the effect of the orthotropic material properties and mechanical loading on the performance of cardiac SWE, as it is known that these factors contribute to complex 3D anisotropic shear wave propagation. To investigate the specific impact of these complexities, we constructed a finite element model with an orthotropic material law subjected to different uniaxial stretches to simulate SWE in the stressed cardiac wall. Group and phase speed were analyzed in function of tissue thickness and virtual probe rotation angle. Tissue stretching increased the group and phase speed of the simulated shear wave, especially in the direction of the muscle fiber. As the model provided access to the true fiber orientation and material properties, we assessed the accuracy of two fiber orientation extraction methods based on SWE. We found a higher accuracy (but lower robustness) when extracting fiber orientations based on the location of maximal shear wave speed instead of the angle of the major axis of the ellipsoidal group speed surface. Both methods had a comparable performance for the center region of the cardiac wall, and performed less well towards the edges. Lastly, we also assessed the (theoretical) impact of pathology on shear wave physics and characterization in the model. It was found that SWE was able to detect changes in fiber orientation and material characteristics, potentially associated with cardiac pathologies such as myocardial fibrosis. Furthermore, the model showed clearly altered shear wave patterns for the fibrotic myocardium compared to the healthy myocardium, which forms an initial but promising outcome of this modeling study.

Three weights higher order Hardy type inequalities

Directory of Open Access Journals (Sweden)

Aigerim A. Kalybay

2006-01-01

Full Text Available We investigate the following three weights higher order Hardy type inequality (0.1 ‖g‖q,u≤  C‖Dρkg‖p,v where Dρi denotes the following weighted differential operator: {dig(tdti,i=0,1,...,m−1,di−mdti−m(p(tdmg(tdtm,i=m,m+1,...,k, for a weight function ρ(⋅. A complete description of the weights u, v and ρ so that (0.1 holds was given in [4] for the case 1

On the Entropy Based Associative Memory Model with Higher-Order Correlations

Directory of Open Access Journals (Sweden)

Masahiro Nakagawa

2010-01-01

Full Text Available In this paper, an entropy based associative memory model will be proposed and applied to memory retrievals with an orthogonal learning model so as to compare with the conventional model based on the quadratic Lyapunov functional to be minimized during the retrieval process. In the present approach, the updating dynamics will be constructed on the basis of the entropy minimization strategy which may be reduced asymptotically to the above-mentioned conventional dynamics as a special case ignoring the higher-order correlations. According to the introduction of the entropy functional, one may involve higer-order correlation effects between neurons in a self-contained manner without any heuristic coupling coefficients as in the conventional manner. In fact we shall show such higher order coupling tensors are to be uniquely determined in the framework of the entropy based approach. From numerical results, it will be found that the presently proposed novel approach realizes much larger memory capacity than that of the quadratic Lyapunov functional approach, e.g., associatron.

Design proposal for ultimate shear strength of tapered steel plate girders

Directory of Open Access Journals (Sweden)

A. Bedynek

2017-03-01

Full Text Available Numerous experimental and numerical studies on prismatic plate girders subjected to shear can be found in the literature. However, the real structures are frequently designed as non-uniform structural elements. The main objective of the research is the development of a new proposal for the calculation of the ultimate shear resistance of tapered steel plate girders taking into account the specific behaviour of such members. A new mechanical model is presented in the paper and it is used to show the differences between the behaviour of uniform and tapered web panels subjected to shear. EN 1993-1-5 design specifications for the determination of the shear strength for rectangular plates are improved in order to assess the shear strength of tapered elements. Numerical studies carried out on tapered steel plate girders subjected to shear lead to confirm the suitability of the mechanical model and the proposed design expression.

A single dose of oxytocin nasal spray improves higher-order social cognition in schizophrenia.

Science.gov (United States)

Guastella, Adam J; Ward, Philip B; Hickie, Ian B; Shahrestani, Sara; Hodge, Marie Antoinette Redoblado; Scott, Elizabeth M; Langdon, Robyn

2015-11-01

Schizophrenia is associated with significant impairments in both higher and lower order social cognitive performance and these impairments contribute to poor social functioning. People with schizophrenia report poor social functioning to be one of their greatest unmet treatment needs. Recent studies have suggested the potential of oxytocin as such a treatment, but mixed results render it uncertain what aspects of social cognition are improved by oxytocin and, subsequently, how oxytocin might best be applied as a therapeutic. The aim of this study was to determine whether a single dose of oxytocin improved higher-order and lower-order social cognition performance for patients with schizophrenia across a well-established battery of social cognition tests. Twenty-one male patients received both a single dose of oxytocin nasal spray (24IU) and a placebo, two weeks apart in a randomized within-subjects placebo controlled design. Following each administration, participants completed the social cognition tasks, as well as a test of general neurocognition. Results revealed that oxytocin particularly enhanced performance on higher order social cognition tasks, with no effects on general neurocognition. Results for individual tasks showed most improvement on tests measuring appreciation of indirect hints and recognition of social faux pas. These results suggest that oxytocin, if combined to enhance social cognition learning, may be beneficial when targeted at higher order social cognition domains. This study also suggests that these higher order tasks, which assess social cognitive processing in a social communication context, may provide useful markers of response to oxytocin in schizophrenia. Copyright © 2015 Elsevier B.V. All rights reserved.

Modeling Human Behaviour with Higher Order Logic: Insider Threats

DEFF Research Database (Denmark)

Boender, Jaap; Ivanova, Marieta Georgieva; Kammuller, Florian

2014-01-01

it to the sociological process of logical explanation. As a case study on modeling human behaviour, we present the modeling and analysis of insider threats as a Higher Order Logic theory in Isabelle/HOL. We show how each of the three step process of sociological explanation can be seen in our modeling of insider’s state......, its context within an organisation and the effects on security as outcomes of a theorem proving analysis....

Higher order multi-term time-fractional partial differential equations involving Caputo-Fabrizio derivative

OpenAIRE

Erkinjon Karimov; Sardor Pirnafasov

2017-01-01

In this work we discuss higher order multi-term partial differential equation (PDE) with the Caputo-Fabrizio fractional derivative in time. Using method of separation of variables, we reduce fractional order partial differential equation to the integer order. We represent explicit solution of formulated problem in particular case by Fourier series.

Shear weakening for different lithologies observed at different saturation stages

Science.gov (United States)

Diethart-Jauk, Elisabeth; Gegenhuber, Nina

2018-01-01

For this study, samples from different lithologies ("Leitha"-limestone, "Dachstein"-limestone, "Haupt"-dolomite, "Bunt"-sandstone, Grey Berea sandstone, granite, quartzite and basalt) were selected. Samples were dried at 70 °C, respectively 105 °C and were saturated with brine. Mass, porosity, permeability, compressional and shear wave velocity were determined from dry and brine saturated samples at laboratory conditions, based on an individual measurement program. Shear modulus was calculated to find out, if shear weakening exists for the dataset. Shear weakening means that shear modulus of dry samples is higher than of saturated samples, but it is assumed that shear modulus is unaffected by saturation. "Dachstein"-limestone and basalt show shear weakening, quartzite samples show both weakening and hardening. Granite samples are affected by temperature, after drying with 105 °C no change can be observed anymore. "Bunt"-sandstone samples show a change in the shear modulus in a small extent, although they may contain clay minerals. The other lithologies show no effect. Explanations for carbonate samples can be the complicated pore structure, for basalt it could be that weathering creates clay minerals which are known as causes for a change of the shear modulus. Fluid viscosity can also be an important factor.

Asymptotic estimates and exponential stability for higher-order monotone difference equations

Directory of Open Access Journals (Sweden)

Pituk Mihály

2005-01-01

Full Text Available Asymptotic estimates are established for higher-order scalar difference equations and inequalities the right-hand sides of which generate a monotone system with respect to the discrete exponential ordering. It is shown that in some cases the exponential estimates can be replaced with a more precise limit relation. As corollaries, a generalization of discrete Halanay-type inequalities and explicit sufficient conditions for the global exponential stability of the zero solution are given.

Asymptotic estimates and exponential stability for higher-order monotone difference equations

Directory of Open Access Journals (Sweden)

Mihály Pituk

2005-03-01

Full Text Available Asymptotic estimates are established for higher-order scalar difference equations and inequalities the right-hand sides of which generate a monotone system with respect to the discrete exponential ordering. It is shown that in some cases the exponential estimates can be replaced with a more precise limit relation. As corollaries, a generalization of discrete Halanay-type inequalities and explicit sufficient conditions for the global exponential stability of the zero solution are given.

The molecular dynamics simulation of structure and transport properties of sheared super-cooled liquid metal

International Nuclear Information System (INIS)

Wang Li; Liu Xiangfa; Zhang Yanning; Yang Hua; Chen Ying; Bian Xiufang

2003-01-01

Much more attention has been paid to the microstructure of liquid metal under non-ordinary condition recently. In this Letter, the pair correlation function (PCF), together with internal energy of sheared super-cooled liquid Co as a function of temperature has been calculated by molecular dynamics simulation based upon the embedded atom method (EAM) and analyzed compared to that under normal condition. The finding indicates that there exist three obvious peaks of PCF for liquid Co; while as the shear stress is applied to the liquid, the first and second peaks of PCF become lower, the third peak disappeared. The concentric shell structure representing short-range order of liquid still exists, however, it is weakened by the addition of shear stress, leading to the increases of disordering degree of liquid metal. The curves of energy versus temperature suggest the higher crystalline temperature compared to that under normal condition at the same cooling rate. In addition, the viscosity of super-liquid Co is calculated by non-equilibrium molecular dynamics (NEMD)

Shear dilatancy and acoustic emission in dry and saturated granular materials

Science.gov (United States)

Brodsky, E. E.; Siman-Tov, S.

2017-12-01

Shearing of granular materials plays a strong role in naturally sheared systems as landslides and faults. Many works on granular flows have concentrated on dry materials, but relatively little work has been done on water saturated sands. Here we experimentally investigate dry versus saturated quartz-rich sand to understand the effect of the fluid medium on the rheology and acoustic waves emission of the sheared sand. The sand was sheared in a rotary shear rheometer under applied constant normal stress boundary at low (100 µm/s) to high (1 m/s) velocities. Mechanical, acoustic data and deformation were continuously recorded and imaged. For dry and water saturated experiments the granular volume remains constant for low shear velocities ( 10-3 m/s) and increases during shearing at higher velocities ( 1 m/s). Continuous imaging of the sheared sand show that the steady state shear band thickness is thicker during the high velocity steps. No significant change observed in the shear band thickness between dry and water saturated experiments. In contrast, the amount of dilation during water saturated experiments is about half the value measured for dry material. The measured decrease cannot be explained by shear band thickness change as such is not exist. However, the reduced dilation is supported by our acoustic measurements. In general, the event rate and acoustic event amplitudes increase with shear velocity. While isolated events are clearly detected during low velocities at higher the events overlap, resulting in a noisy signal. Although detection is better for saturated experiments, during the high velocity steps the acoustic energy measured from the signal is lower compared to that recorded for dry experiments. We suggest that the presence of fluid suppresses grain motion and particles impacts leading to mild increase in the internal pressure and therefore for the reduced dilation. In addition, the viscosity of fluids may influence the internal pressure via

Higher-order human telomeric G-quadruplex DNA metalloenzymes enhance enantioselectivity in the Diels-Alder reaction.

Science.gov (United States)

Li, Yinghao; Jia, Guoqing; Wang, Changhao; Cheng, Mingpan; Li, Can

2015-03-02

Short human telomeric (HT) DNA sequences form single G-quadruplex (G4 ) units and exhibit structure-based stereocontrol for a series of reactions. However, for more biologically relevant higher-order HT G4 -DNAs (beyond a single G4 unit), the catalytic performances are unknown. Here, we found that higher-order HT G4 -DNA copper metalloenzymes (two or three G4 units) afford remarkably higher enantioselectivity (>90 % ee) and a five- to sixfold rate increase, compared to a single G4 unit, for the Diels-Alder reaction. Electron paramagnetic resonance (EPR) and enzymatic kinetic studies revealed that the distinct catalytic function between single and higher-order G4 -DNA copper metalloenzymes can be attributed to different Cu(II) coordination environments and substrate specificity. Our finding suggests that, like protein enzymes and ribozymes, higher-order structural organization is crucial for G4 -DNA-based catalysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On a higher order multi-term time-fractional partial differential equation involving Caputo-Fabrizio derivative

OpenAIRE

Pirnapasov, Sardor; Karimov, Erkinjon

2017-01-01

In the present work we discuss higher order multi-term partial differential equation (PDE) with the Caputo-Fabrizio fractional derivative in time. We investigate a boundary value problem for fractional heat equation involving higher order Caputo-Fabrizio derivatives in time-variable. Using method of separation of variables and integration by parts, we reduce fractional order PDE to the integer order. We represent explicit solution of formulated problem in particular case by Fourier series.

How shear increments affect the flow production branching ratio in CSDX

Science.gov (United States)

Li, J. C.; Diamond, P. H.

2018-06-01

The coupling of turbulence-driven azimuthal and axial flows in a linear device absent magnetic shear (Controlled Shear Decorrelation Experiment) is investigated. In particular, we examine the apportionment of Reynolds power between azimuthal and axial flows, and how the azimuthal flow shear affects axial flow generation and saturation by drift wave turbulence. We study the response of the energy branching ratio, i.e., ratio of axial and azimuthal Reynolds powers, PzR/PyR , to incremental changes of azimuthal and axial flow shears. We show that increasing azimuthal flow shear decreases the energy branching ratio. When axial flow shear increases, this ratio first increases but then decreases to zero. The axial flow shear saturates below the threshold for parallel shear flow instability. The effects of azimuthal flow shear on the generation and saturation of intrinsic axial flows are analyzed. Azimuthal flow shear slows down the modulational growth of the seed axial flow shear, and thus reduces intrinsic axial flow production. Azimuthal flow shear reduces both the residual Reynolds stress (of axial flow, i.e., ΠxzR e s ) and turbulent viscosity ( χzDW ) by the same factor |⟨vy⟩'|-2Δx-2Ln-2ρs2cs2 , where Δx is the distance relative to the reference point where ⟨vy⟩=0 in the plasma frame. Therefore, the stationary state axial flow shear is not affected by azimuthal flow shear to leading order since ⟨vz⟩'˜ΠxzR e s/χzDW .

Ultra-compact broadband higher order-mode pass filter fabricated in a silicon waveguide for multimode photonics

DEFF Research Database (Denmark)

Guan, Xiaowei; Ding, Yunhong; Frandsen, Lars Hagedorn

2015-01-01

An ultra-compact and broadband higher order-mode pass filter in a 1D photonic crystal silicon waveguide is proposed and experimentally demonstrated. The photonic crystal is designed for the lower order mode to work in the photonic band gap, while the higher order mode is located in the air band....... Consequently, light on the lower order mode is prohibited to pass through the filter, while light on a higher order mode can be converted to a Bloch mode in the photonic crystal and pass through the filter with low insertion loss. As an example, we fabricate a similar to 15-mu m-long first-order-mode pass...

Dynamics of massless higher spins in the second order in curvatures

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, M A [International Centre for Theoretical Physics, Trieste (Italy)

1990-04-05

The consistent equations of motion of interacting massless fields of all spins s=0, 1/2, 1, ..., {infinity} are constructed explicitly to the second order of the expansion in powers of the higher spin strengths. (orig.).

Optimizing students’ scientific communication skills through higher order thinking virtual laboratory (HOTVL)

Science.gov (United States)

Sapriadil, S.; Setiawan, A.; Suhandi, A.; Malik, A.; Safitri, D.; Lisdiani, S. A. S.; Hermita, N.

2018-05-01

Communication skill is one skill that is very needed in this 21st century. Preparing and teaching this skill in teaching physics is relatively important. The focus of this research is to optimizing of students’ scientific communication skills after the applied higher order thinking virtual laboratory (HOTVL) on topic electric circuit. This research then employed experimental study particularly posttest-only control group design. The subject in this research involved thirty senior high school students which were taken using purposive sampling. A sample of seventy (70) students participated in the research. An equivalent number of thirty five (35) students were assigned to the control and experimental group. The results of this study found that students using higher order thinking virtual laboratory (HOTVL) in laboratory activities had higher scientific communication skills than students who used the verification virtual lab.

Symbolic Algebra Development for Higher-Order Electron Propagator Formulation and Implementation.

Science.gov (United States)

Tamayo-Mendoza, Teresa; Flores-Moreno, Roberto

2014-06-10

Through the use of symbolic algebra, implemented in a program, the algebraic expression of the elements of the self-energy matrix for the electron propagator to different orders were obtained. In addition, a module for the software package Lowdin was automatically generated. Second- and third-order electron propagator results have been calculated to test the correct operation of the program. It was found that the Fortran 90 modules obtained automatically with our algorithm succeeded in calculating ionization energies with the second- and third-order electron propagator in the diagonal approximation. The strategy for the development of this symbolic algebra program is described in detail. This represents a solid starting point for the automatic derivation and implementation of higher-order electron propagator methods.

Higher Order Modes Excitation of Micro Cantilever Beams

KAUST Repository

Jaber, Nizar

2014-05-01

In this study, we present analytical and experimental investigation of electrically actuated micro cantilever based resonators. These devices are fabricated using polyimide and coated with chrome and gold layers from both sides. The cantilevers are highly curled up due to stress gradient, which is a common imperfection in surface micro machining. Using a laser Doppler vibrometer, we applied a noise signal to experimentally find the first four resonance frequencies. Then, using a data acquisition card, we swept the excitation frequency around the first four natural modes of vibrations. Theoretically, we derived a reduced order model using the Galerkin method to simulate the dynamics of the system. Extensive numerical analysis and computations were performed. The numerical analysis was able to provide good matching with experimental values of the resonance frequencies. Also, we proved the ability to excite higher order modes using partial electrodes with shapes that resemble the shape of the mode of interest. Such micro-resonators are shown to be promising for applications in mass and gas sensing.

Higher-order gravity and the classical equivalence principle

Science.gov (United States)

Accioly, Antonio; Herdy, Wallace

2017-11-01

As is well known, the deflection of any particle by a gravitational field within the context of Einstein’s general relativity — which is a geometrical theory — is, of course, nondispersive. Nevertheless, as we shall show in this paper, the mentioned result will change totally if the bending is analyzed — at the tree level — in the framework of higher-order gravity. Indeed, to first order, the deflection angle corresponding to the scattering of different quantum particles by the gravitational field mentioned above is not only spin dependent, it is also dispersive (energy-dependent). Consequently, it violates the classical equivalence principle (universality of free fall, or equality of inertial and gravitational masses) which is a nonlocal principle. However, contrary to popular belief, it is in agreement with the weak equivalence principle which is nothing but a statement about purely local effects. It is worthy of note that the weak equivalence principle encompasses the classical equivalence principle locally. We also show that the claim that there exists an incompatibility between quantum mechanics and the weak equivalence principle, is incorrect.

High fluid shear strain causes injury in silver shark: Preliminary implications for Mekong hydropower turbine design

Energy Technology Data Exchange (ETDEWEB)

Baumgartner, L. J. [New South Wales Department of Primary Industries, Narrandera Fisheries Centre, Narrandera NSW Australia; Institute of Land, Water and Society, Charles Sturt University, Albury NSW Australia; Thorncraft, G. [Faculty of Agriculture, Forestry and Fisheries, National University of Laos, Vientiane Lao People’s Democratic Republic; Phonekhampheng, O. [Faculty of Agriculture, Forestry and Fisheries, National University of Laos, Vientiane Lao People’s Democratic Republic; Boys, C. [New South Wales Department of Primary Industries, Port Stephens Fisheries Institute, Nelson Bay NSW Australia; Navarro, A. [Institute of Land, Water and Society, Charles Sturt University, Albury NSW Australia; Robinson, W. [Institute of Land, Water and Society, Charles Sturt University, Albury NSW Australia; Brown, R. [Pacific Northwest National Laboratory, Richland WA USA; Deng, Z. D. [Pacific Northwest National Laboratory, Richland WA USA

2017-02-09

Fluid shear arises when two bodies of water, travelling at different velocities, intersect. Fish entrained at the interface of these two water masses will experience shear stress; which can be harmful. The stress magnitude is dependent on waterbody mass and velocity; with the fish impact largely related to body size. Elevated shear stress occurs where rapidly flowing water passes near spillways, across screens, within turbine draft tubes or other passage routes. A flume was used to determine critical tolerances of silver shark (Balantiocheilos melanopterus) to different shear stress rates generated by a high velocity jet. Fish experienced higher levels of injury and mortality as shear stress was increased. Excessive shear forces had damaging impacts on fish. Mortality occurred at shear levels higher that 600/s. It is important that developers should attempt to model potential shear profiles expected during turbine passage in selected designs. These data will be critical to determine potential impacts on fish. If the likelihood of adverse impact is high, then alternative designs which have lower shear stress could be explored.

Real-time shear wave elastography may predict autoimmune thyroid disease.

Science.gov (United States)

Vlad, Mihaela; Golu, Ioana; Bota, Simona; Vlad, Adrian; Timar, Bogdan; Timar, Romulus; Sporea, Ioan

2015-05-01

To evaluate and compare the values of the elasticity index as measured by shear wave elastography in healthy subjects and in patients with autoimmune thyroid disease, in order to establish if this investigation can predict the occurrence of autoimmune thyroid disease. A total of 104 cases were included in the study group: 91 women (87.5%), out of which 52 (50%) with autoimmune thyroid disease diagnosed by specific tests and 52 (50%) healthy volunteers, matched for age and gender. For all the subjects, three measurements were performed on each thyroid lobe and a mean value was calculated. The data were expressed in kPa. The investigation was performed with an Aixplorer system (SuperSonic Imagine, France), using a linear high-resolution 15-4 MHz transducer. The mean value for the elasticity index was similar in the right and the left thyroid lobes, both in normal subjects and in patients with autoimmune thyroid disease: 19.6 ± 6.6 vs. 19.5 ± 6.8 kPa, p = 0.92, and 26.6 ± 10.0 vs. 25.8 ± 11.7 kPa, p = 0.71, respectively. This parameter was significantly higher in patients with autoimmune thyroid disease than in controls (p < 0.001). For a cut-off value of 22.3 kPa, which resulted in the highest sum of sensitivity and specificity, the elasticity index assessed by shear wave elastography had a sensitivity of 59.6% and a specificity of 76.9% (AUROC = 0.71; p < 0.001) for predicting the presence of autoimmune thyroid disease. Quantitative elasticity index measured by shear wave elastography was significantly higher in autoimmune thyroid disease than in normal thyroid parenchyma and may predict the presence of autoimmune thyroid disease.

Exploratory Movement Generates Higher-Order Information That Is Sufficient for Accurate Perception of Scaled Egocentric Distance

Science.gov (United States)

Mantel, Bruno; Stoffregen, Thomas A.; Campbell, Alain; Bardy, Benoît G.

2015-01-01

Body movement influences the structure of multiple forms of ambient energy, including optics and gravito-inertial force. Some researchers have argued that egocentric distance is derived from inferential integration of visual and non-visual stimulation. We suggest that accurate information about egocentric distance exists in perceptual stimulation as higher-order patterns that extend across optics and inertia. We formalize a pattern that specifies the egocentric distance of a stationary object across higher-order relations between optics and inertia. This higher-order parameter is created by self-generated movement of the perceiver in inertial space relative to the illuminated environment. For this reason, we placed minimal restrictions on the exploratory movements of our participants. We asked whether humans can detect and use the information available in this higher-order pattern. Participants judged whether a virtual object was within reach. We manipulated relations between body movement and the ambient structure of optics and inertia. Judgments were precise and accurate when the higher-order optical-inertial parameter was available. When only optic flow was available, judgments were poor. Our results reveal that participants perceived egocentric distance from the higher-order, optical-inertial consequences of their own exploratory activity. Analysis of participants’ movement trajectories revealed that self-selected movements were complex, and tended to optimize availability of the optical-inertial pattern that specifies egocentric distance. We argue that accurate information about egocentric distance exists in higher-order patterns of ambient energy, that self-generated movement can generate these higher-order patterns, and that these patterns can be detected and used to support perception of egocentric distance that is precise and accurate. PMID:25856410

Higher-order topological insulators and superconductors protected by inversion symmetry

Science.gov (United States)

Khalaf, Eslam

2018-05-01

We study surface states of topological crystalline insulators and superconductors protected by inversion symmetry. These fall into the category of "higher-order" topological insulators and superconductors which possess surface states that propagate along one-dimensional curves (hinges) or are localized at some points (corners) on the surface. We provide a complete classification of inversion-protected higher-order topological insulators and superconductors in any spatial dimension for the 10 symmetry classes by means of a layer construction. We discuss possible physical realizations of such states starting with a time-reversal-invariant topological insulator (class AII) in three dimensions or a time-reversal-invariant topological superconductor (class DIII) in two or three dimensions. The former exhibits one-dimensional chiral or helical modes propagating along opposite edges, whereas the latter hosts Majorana zero modes localized to two opposite corners. Being protected by inversion, such states are not pinned to a specific pair of edges or corners, thus offering the possibility of controlling their location by applying inversion-symmetric perturbations such as magnetic field.

Dynamics of massless higher spins in the second order in curvatures

International Nuclear Information System (INIS)

Vasiliev, M.A.

1989-08-01

The consistent equations of motion of interacting fields of all spins s=0,1/2,1...∞ are constructed explicitly to the second order of the expansion in powers of the higher spin strengths. (author). 14 refs

Higher order multi-term time-fractional partial differential equations involving Caputo-Fabrizio derivative

Directory of Open Access Journals (Sweden)

Erkinjon Karimov

2017-10-01

Full Text Available In this work we discuss higher order multi-term partial differential equation (PDE with the Caputo-Fabrizio fractional derivative in time. Using method of separation of variables, we reduce fractional order partial differential equation to the integer order. We represent explicit solution of formulated problem in particular case by Fourier series.

Statistical Model of Extreme Shear

DEFF Research Database (Denmark)

Larsen, Gunner Chr.; Hansen, Kurt Schaldemose

2004-01-01

In order to continue cost-optimisation of modern large wind turbines, it is important to continously increase the knowledge on wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...... by a model that, on a statistically consistent basis, describe the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of high-sampled full-scale time series measurements...... are consistent, given the inevitabel uncertainties associated with model as well as with the extreme value data analysis. Keywords: Statistical model, extreme wind conditions, statistical analysis, turbulence, wind loading, statistical analysis, turbulence, wind loading, wind shear, wind turbines....

Experimental study of the vortex-induced vibration of drilling risers under the shear flow with the same shear parameter at the different Reynolds numbers.

Science.gov (United States)

Liangjie, Mao; Qingyou, Liu; Shouwei, Zhou

2014-01-01

A considerable number of studies for VIV under the uniform flow have been performed. However, research on VIV under shear flow is scarce. An experiment for VIV under the shear flow with the same shear parameter at the two different Reynolds numbers was conducted in a deep-water offshore basin. Various measurements were obtained by the fiber bragg grating strain sensors. Experimental data were analyzed by modal analysis method. Results show several valuable features. First, the corresponding maximum order mode of the natural frequency for shedding frequency is the maximum dominant vibration mode and multi-modal phenomenon is appeared in VIV under the shear flow, and multi-modal phenomenon is more apparent at the same shear parameter with an increasing Reynolds number under the shear flow effect. Secondly, the riser vibrates at the natural frequency and the dominant vibration frequency increases for the effect of the real-time tension amplitude under the shear flow and the IL vibration frequency is the similar with the CF vibration frequency at the Reynolds number of 1105 in our experimental condition and the IL dominant frequency is twice the CF dominant frequency with an increasing Reynolds number. In addition, the displacement trajectories at the different locations of the riser appear the same shape and the shape is changed at the same shear parameter with an increasing Reynolds number under the shear flow. The diagonal displacement trajectories are observed at the low Reynolds number and the crescent-shaped displacement trajectories appear with an increasing Reynolds number under shear flow in the experiment.

Experimental study of the vortex-induced vibration of drilling risers under the shear flow with the same shear parameter at the different Reynolds numbers.

Directory of Open Access Journals (Sweden)

Mao Liangjie

Full Text Available A considerable number of studies for VIV under the uniform flow have been performed. However, research on VIV under shear flow is scarce. An experiment for VIV under the shear flow with the same shear parameter at the two different Reynolds numbers was conducted in a deep-water offshore basin. Various measurements were obtained by the fiber bragg grating strain sensors. Experimental data were analyzed by modal analysis method. Results show several valuable features. First, the corresponding maximum order mode of the natural frequency for shedding frequency is the maximum dominant vibration mode and multi-modal phenomenon is appeared in VIV under the shear flow, and multi-modal phenomenon is more apparent at the same shear parameter with an increasing Reynolds number under the shear flow effect. Secondly, the riser vibrates at the natural frequency and the dominant vibration frequency increases for the effect of the real-time tension amplitude under the shear flow and the IL vibration frequency is the similar with the CF vibration frequency at the Reynolds number of 1105 in our experimental condition and the IL dominant frequency is twice the CF dominant frequency with an increasing Reynolds number. In addition, the displacement trajectories at the different locations of the riser appear the same shape and the shape is changed at the same shear parameter with an increasing Reynolds number under the shear flow. The diagonal displacement trajectories are observed at the low Reynolds number and the crescent-shaped displacement trajectories appear with an increasing Reynolds number under shear flow in the experiment.

Shear thinning and shear thickening of a confined suspension of vesicles

Science.gov (United States)

Nait Ouhra, A.; Farutin, A.; Aouane, O.; Ez-Zahraouy, H.; Benyoussef, A.; Misbah, C.

2018-01-01

Widely regarded as an interesting model system for studying flow properties of blood, vesicles are closed membranes of phospholipids that mimic the cytoplasmic membranes of red blood cells. In this study we analyze the rheology of a suspension of vesicles in a confined geometry: the suspension, bound by two planar rigid walls on each side, is subject to a shear flow. Flow properties are then analyzed as a function of shear rate γ ˙, the concentration of the suspension ϕ , and the viscosity contrast λ =ηin/ηout , where ηin and ηout are the fluid viscosities of the inner and outer fluids, respectively. We find that the apparent (or effective viscosity) of the suspension exhibits both shear thinning (decreasing viscosity with shear rate) or shear thickening (increasing viscosity with shear rate) in the same concentration range. The shear thinning or thickening behaviors appear as subtle phenomena, dependant on viscosity contrast λ . We provide physical arguments on the origins of these behaviors.

Higher-order Peregrine combs and Peregrine walls for the variable-coefficient Lenells-Fokas equation

Science.gov (United States)

Wang, Zi-Qi; Wang, Xin; Wang, Lei; Sun, Wen-Rong; Qi, Feng-Hua

2017-02-01

In this paper, we study the variable-coefficient Lenells-Fokas (LF) model. Under large periodic modulations in the variable coefficients of the LF model, the generalized Akhmediev breathers develop into the breather multiple births (BMBs) from which we obtain the Peregrine combs (PCs). The PCs can be considered as the limiting case of the BMBs and be transformed into the Peregrine walls (PWs) with a specific amplitude of periodic modulation. We further investigate the spatiotemporal characteristics of the PCs and PWs analytically. Based on the second-order breather and rogue-wave solutions, we derive the corresponding higher-order structures (higher-order PCs and PWs) under proper periodic modulations. What is particularly noteworthy is that the second-order PC can be converted into the Peregrine pyramid which exhibits the higher amplitude and thickness. Our results could be helpful for the design of experiments in the optical fiber communications.

Threshold resummation and higher order effects in QCD

International Nuclear Information System (INIS)

Ringer, Felix Maximilian

2015-01-01

Quantum chromodynamics (QCD) is a quantum field theory that describes the strong interactions between quarks and gluons, the building blocks of all hadrons. Thanks to the experimental progress over the past decades, there has been an ever-growing need for QCD precision calculations for scattering processes involving hadrons. For processes at large momentum transfer, perturbative QCD offers a systematic approach for obtaining precise predictions. This approach relies on two key concepts: the asymptotic freedom of QCD and factorization. In a perturbative calculation at higher orders, the infrared cancellation between virtual and real emission diagrams generally leaves behind logarithmic contributions. In many observables relevant for hadronic scattering these logarithms are associated with a kinematic threshold and are hence known as ''threshold logarithms''. They become large when the available phase space for real gluon emission shrinks. In order to obtain a reliable prediction from QCD, the threshold logarithms need to be taken into account to all orders in the strong coupling constant, a procedure known as ''threshold resummation''. The main focus of my PhD thesis is on studies of QCD threshold resummation effects beyond the next-to-leading logarithmic order. Here we primarily consider the production of hadron pairs in hadronic collisions as an example. In addition, we also consider hadronic jet production, which is particularly interesting for the phenomenology at the LHC. For both processes, we fully take into account the non-trivial QCD color structure of the underlying partonic hard- scattering cross sections. We find that threshold resummation leads to sizable numerical effects in the kinematic regimes relevant for comparisons to experimental data.

Higher-order asymptotic homogenization of periodic materials with low scale separation

NARCIS (Netherlands)

Ameen, M.M.; Peerlings, R.H.J.; Geers, M.G.D

2016-01-01

In this work, we investigate the limits of classical homogenization theories pertaining to homogenization of periodic linear elastic composite materials at low scale separations and demonstrate the effectiveness of higher-order periodic homogenization in alleviating this limitation. Classical

First Measurements of Higher Order Optics Parameters in the LHC

CERN Document Server

Vanbavinckhove, G; Bartolini, R; Calaga, R; Giovannozzi, M; Maclean, E H; Miyamoto, R; Schmidt, F; Tomas, R

2011-01-01

Higher order effects can play an important role in the performance of the LHC. Lack of knowledge of these pa- rameters can increase the tune footprint and compromise the beam lifetime. First measurements of these parameters at injection and flattop have been conducted. Detailed sim- ulations are compared to the measurements together with discussions on the measurement limitations.

Estimation of shear stress in counter-current gas-liquid annular two-phase flow

International Nuclear Information System (INIS)

Abe, Yutaka; Akimoto, Hajime; Murao, Yoshio

1991-01-01

The accuracy of the correlations of the friction factor is important for the counter-current flow (CCF) analysis with two-fluid model. However, existing two fluid model codes use the correlations of friction factors for co-current flow or correlation developed based on the assumption of no wall shear stress. The assessment calculation for two fluid model code with those existing correlations of friction factors shows the falling water flow rate is overestimated. Analytical model is developed to calculate the shear stress distribution in water film at CCF in order to get the information on the shear stress at the interface and the wall. The analytical results with the analysis model and Bharathan's CCF data shows that the wall shear stress acting on the falling water film is almost same order as the interfacial shear stress and the correlations for co-current flow cannot be applied to the counter-current flow. Tentative correlations of the interfacial and the wall friction factors are developed based on the results of the present study. (author)

Development of higher order mode couplers at Cornell

International Nuclear Information System (INIS)

Amato, J.C.

1988-01-01

Higher order mode (HOM) couplers are integral parts of a superconducting accelerator cavity. The damping which the couplers must provide is dictated by the frequency and shunt impedance of the cavity modes as well as by the stability requirements of the accelerator incorporating the cavities. Cornell's 5-cell 1500 MHz elliptical cavity was designed for use in a 50 x 50 GeV electron-positron storage ring with a total beam current of 3.5 mA (CESR-II). HOM couplers for the Cornell cavity were designed and evaluated with this machine in mind. The development of these couplers is described in this paper. 8 references, 8 figures

Higher order branching of periodic orbits from polynomial isochrones

Directory of Open Access Journals (Sweden)

B. Toni

1999-09-01

Full Text Available We discuss the higher order local bifurcations of limit cycles from polynomial isochrones (linearizable centers when the linearizing transformation is explicitly known and yields a polynomial perturbation one-form. Using a method based on the relative cohomology decomposition of polynomial one-forms complemented with a step reduction process, we give an explicit formula for the overall upper bound of branch points of limit cycles in an arbitrary $n$ degree polynomial perturbation of the linear isochrone, and provide an algorithmic procedure to compute the upper bound at successive orders. We derive a complete analysis of the nonlinear cubic Hamiltonian isochrone and show that at most nine branch points of limit cycles can bifurcate in a cubic polynomial perturbation. Moreover, perturbations with exactly two, three, four, six, and nine local families of limit cycles may be constructed.

Large-Amplitude Long-Wave Instability of a Supersonic Shear Layer

Science.gov (United States)

Messiter, A. F.

1995-01-01

For sufficiently high Mach numbers, small disturbances on a supersonic vortex sheet are known to grow in amplitude because of slow nonlinear wave steepening. Under the same external conditions, linear theory predicts slow growth of long-wave disturbances to a thin supersonic shear layer. An asymptotic formulation is given here which adds nonzero shear-layer thickness to the weakly nonlinear formulation for a vortex sheet. Spatial evolution is considered, for a spatially periodic disturbance having amplitude of the same order, in Reynolds number, as the shear-layer thickness. A quasi-equilibrium inviscid nonlinear critical layer is found, with effects of diffusion and slow growth appearing through nonsecularity condition. Other limiting cases are also considered, in an attempt to determine a relationship between the vortex-sheet limit and the long-wave limit for a thin shear layer; there appear to be three special limits, corresponding to disturbances of different amplitudes at different locations along the shear layer.

Predictors of third and Higher order births in India

Directory of Open Access Journals (Sweden)

Payal Singh

2015-12-01

Full Text Available Background: Total fertility rate (TFR reflecting population growth is closely related to higher order parity progression. Many Indian states reached replacement level of TFR, but still states constituting nearly 40% population are with TFR ≥ 3. The predictors are the desire of son’s, poor contraceptives practices, younger age at marriage, child loss and shorter birth spacing. Objective: This analysis assessed the degree of relation of 3rd and higher order parity progression with the above mentioned predictors. Material and Methods: State/Union Territories wise proportions of women: progressing to ≥3 births, more sons desire, birth spacing <24 months, adopting modern contraception and median marriage age <18 years along with infant mortality rate (IMR were taken from NFHS-III report. Correlation matrix and stepwise forward multiple regression carried. Significance was seen at 5%. Results: Hindi speaking states constituting 38.92% nation population recorded TFR ≥3. Positive correlation of mothers progressing ≥ 3 births was highest (0.746 with those desiring more sons followed by IMR (0.445; while maximum negative correlation with those practicing modern contraceptives (-0.565 followed by median age at marriage (-0.391. Multiple regression analysis in order identified desire of more sons, practicing modern contraception and shorter birth spacing as the significant predictors and jointly explained 77.9% of the total variation with gain of 15.5% by adding modern contraceptive practice and 8.3% by adding shorter birth spacing. Conclusions: Desire of more sons appeared the most important predictor to progress ≥3 births that is governed by society culture and educational attainment, require attitudinal change. Further, mothers need motivation to practice both spacing and terminal methods once family is complete.

Ballooning instabilities in tokamaks with sheared toroidal flows

International Nuclear Information System (INIS)

Waelbroeck, F.L.; Chen, L.

1990-11-01

The stability of ballooning modes in the presence of sheared toroidal flows is investigated. The eigenmodes are shown to be related by a Fourier transformation to the non-exponentially growing Floquet solutions found by Cooper. It is further shown that the problem cannot be reduced further than to a two dimensional partial differential equation. Next, the generalized ballooning equation is solved analytically for a circular tokamak equilibrium with sonic flows, but with a small rotation shear compared to the sound speed. With this ordering, the centrifugal forces are comparable to the pressure gradient forces driving the instability, but coupling of the mode with the sound wave is avoided. A new stability criterion is derived which explicitly demonstrates that flow shear is stabilizing at constant centrifugal force gradient. 34 refs

Higher-Order Blind Signal Feature Separation: An Enabling Technology for Battlefield Awareness

National Research Council Canada - National Science Library

Su, Wei; Kosinski, John A

2006-01-01

Higher-order transform blind signal feature classification is discussed for separating bar-shaped, circular, squared, circular-squared, and offset-diamonded constellation patterns of digital linear signals...

Piecewise parabolic method for simulating one-dimensional shear shock wave propagation in tissue-mimicking phantoms

Science.gov (United States)

Tripathi, B. B.; Espíndola, D.; Pinton, G. F.

2017-11-01

The recent discovery of shear shock wave generation and propagation in the porcine brain suggests that this new shock phenomenology may be responsible for a broad range of traumatic injuries. Blast-induced head movement can indirectly lead to shear wave generation in the brain, which could be a primary mechanism for injury. Shear shock waves amplify the local acceleration deep in the brain by up to a factor of 8.5, which may tear and damage neurons. Currently, there are numerical methods that can model compressional shock waves, such as comparatively well-studied blast waves, but there are no numerical full-wave solvers that can simulate nonlinear shear shock waves in soft solids. Unlike simplified representations, e.g., retarded time, full-wave representations describe fundamental physical behavior such as reflection and heterogeneities. Here we present a piecewise parabolic method-based solver for one-dimensional linearly polarized nonlinear shear wave in a homogeneous medium and with empirical frequency-dependent attenuation. This method has the advantage of being higher order and more directly extendable to multiple dimensions and heterogeneous media. The proposed numerical scheme is validated analytically and experimentally and compared to other shock capturing methods. A Riemann step-shock problem is used to characterize the numerical dissipation. This dissipation is then tuned to be negligible with respect to the physical attenuation by choosing an appropriate grid spacing. The numerical results are compared to ultrasound-based experiments that measure planar polarized shear shock wave propagation in a tissue-mimicking gelatin phantom. Good agreement is found between numerical results and experiment across a 40 mm propagation distance. We anticipate that the proposed method will be a starting point for the development of a two- and three-dimensional full-wave code for the propagation of nonlinear shear waves in heterogeneous media.

Experimental investigations of higher-order springing and whipping-WILS project

Directory of Open Access Journals (Sweden)

Hong Sa Young

2014-12-01

Full Text Available Springing and whipping are becoming increasingly important considerations in ship design as container ships increase in size. In this study, the springing and whipping characteristics of a large container ship were investigated through a series of systematic model tests in waves. A multi-segmented hull model with a backbone was adopted for measurement of springing and whipping signals. A conversion method for extracting torsion springing and whipping is described in this paper for the case of an open-section backbone. Higher-order springing, higher-mode torsion responses, and the effects of linear and nonlinear springing in irregular waves are highlighted in the discussion.

Degradation of homogeneous polymer solutions in high shear turbulent pipe flow

Science.gov (United States)

Elbing, B. R.; Winkel, E. S.; Solomon, M. J.; Ceccio, S. L.

2009-12-01

This study quantifies degradation of polyethylene oxide (PEO) and polyacrylamide (PAM) polymer solutions in large diameter (2.72 cm) turbulent pipe flow at Reynolds numbers to 3 × 105 and shear rates greater than 105 1/s. The present results support a universal scaling law for polymer chain scission reported by Vanapalli et al. (2006) that predicts the maximum chain drag force to be proportional to Re 3/2, validating this scaling law at higher Reynolds numbers than prior studies. Use of this scaling gives estimated backbone bond strengths from PEO and PAM of 3.2 and 3.8 nN, respectively. Additionally, with the use of synthetic seawater as a solvent the onset of drag reduction occurred at higher shear rates relative to the pure water solvent solutions, but had little influence on the extent of degradation at higher shear rates. These results are significant for large diameter pipe flow applications that use polymers to reduce drag.

Refined shear correction factor for very thick simply supported and uniformly loaded isosceles right triangular auxetic plates

International Nuclear Information System (INIS)

Lim, Teik-Cheng

2016-01-01

For moderately thick plates, the use of First order Shear Deformation Theory (FSDT) with a constant shear correction factor of 5/6 is sufficient to take into account the plate deflection arising from transverse shear deformation. For very thick plates, the use of Third order Shear Deformation Theory (TSDT) is preferred as it allows the shear strain distribution to be varied through the plate thickness. Therefore no correction factor is required in TSDT, unlike FSDT. Due to the complexity involved in TSDT, this paper obtains a more accurate shear correction factor for use in FSDT of very thick simply supported and uniformly loaded isosceles right triangular plates based on the TSDT. By matching the maximum deflections for this plate according to FSDT and TSDT, a variable shear correction factor is obtained. Results show that the shear correction factor for the simplified TSDT, i.e. 14/17, is least accurate. The commonly adopted shear correction factor of 5/6 in FSDT is valid only for very thin or highly auxetic plates. This paper provides a variable shear correction for FSDT deflection that matches the plate deflection by TSDT. This variable shear correction factor allows designers to justify the use of a commonly adopted shear correction factor of 5/6 even for very thick plates as long as the Poisson’s ratio of the plate material is sufficiently negative. (paper)

A Higher-Order Neural Network Design for Improving Segmentation Performance in Medical Image Series

International Nuclear Information System (INIS)

Selvi, Eşref; Selver, M Alper; Güzeliş, Cüneyt; Dicle, Oǧuz

2014-01-01

Segmentation of anatomical structures from medical image series is an ongoing field of research. Although, organs of interest are three-dimensional in nature, slice-by-slice approaches are widely used in clinical applications because of their ease of integration with the current manual segmentation scheme. To be able to use slice-by-slice techniques effectively, adjacent slice information, which represents likelihood of a region to be the structure of interest, plays critical role. Recent studies focus on using distance transform directly as a feature or to increase the feature values at the vicinity of the search area. This study presents a novel approach by constructing a higher order neural network, the input layer of which receives features together with their multiplications with the distance transform. This allows higher-order interactions between features through the non-linearity introduced by the multiplication. The application of the proposed method to 9 CT datasets for segmentation of the liver shows higher performance than well-known higher order classification neural networks

Observation of neoclassical transport in reverse shear plasmas on TFTR

International Nuclear Information System (INIS)

Efthimion, P.C.; Goeler, S. von; Houlberg, W.A.

1999-01-01

Perturbative experiments on TFTR have investigated the transport of multiple ion species in reverse shear (RS) plasmas. The profile evolutions of trace tritium and helium and intrinsic carbon indicate the formation of core particle transport barriers in enhanced reverse shear (ERS) plasmas. There is an order of magnitude reduction in the particle diffusivity inside the RS region. The diffusivities for these species in ERS plasmas agree with neoclassical theory. (author)

Equivalence of two formalisms for calculating higher order synchrotron sideband spin resonances

International Nuclear Information System (INIS)

Mane, S.R.

1988-01-01

Synchrotron sideband resonances of a first order spin resonance are generally regarded as the most important higher order spin resonances in a high-energy storage ring. Yokoya's formula for these resonances is rederived, including some extra terms, which he neglected, but which turn out to be of comparable magnitude to the terms retained. Including these terms, Yokoya's formalism and the SMILE algorithm are shown to be equivalent to leading order in the resonance strengths. The theoretical calculations are shown to agree with certain measurements from SPEAR

Multipacting and higher order mode analysis of 325 MHz single spoke resonators

International Nuclear Information System (INIS)

Pal, Mukesh Kumar; Gaur, Rahul; Kumar, Vinit

2015-01-01

Superconducting Single Spoke Resonators (SSRs) will be used to accelerate the H - ions from 3 MeV to 160 MeV in the injector linac for the proposed Indian Spallation Neutron Source (ISNS) at RRCAT. Electromagnetic design studies of 325 MHz SSRs have been performed for βg = 0.11, 0.22 and 0.42. Performance of SSRs are typically limited by multipacting phenomenon and higher order modes. In our design, we have performed detailed studies of electron multipacting phenomenon, which is a resonant process, using a computer code CST-PS. Based on this analysis, refinements in the geometry of the SSRs have been made, in order to reduce the growth rate of multipacting. We have also carried out extensive analysis of Higher Order Mode (HOM) for the SSR structure, using the computer code CST-MWS, where the R/Q parameter has been calculated for monopole, dipole and quadrupole HaMs. Details of these calculations will be presented in this paper. (author)

Higher-order aberrations and visual acuity after LASEK.

Science.gov (United States)

Urgancioglu, Berrak; Bilgihan, Kamil; Ozturk, Sertac

2008-08-01

To determine ocular higher-order aberrations (HOAs) in eyes with supernormal vision after myopic astigmatic laser subepithelial keratomileusis (LASEK) and to compare the findings with those in eyes with natural supernormal vision. Ocular HOAs were measured after LASEK in 20 eyes of 12 myopic astigmatic patients with postoperative uncorrected visual acuity (UCVA) of >20/16 (group 1). Patients who were included in the study had no visual symptoms like glare, halo or double vision. The measurements were taken 8.3 +/- 3 months after LASEK surgery. In group 2 ocular HOAs were examined in 20 eyes of 10 subjects with natural UCVA of >20/16 as a control. Measurements were taken across a pupil with a diameter of 4.0 mm and 6.0 mm. Root-mean-square (RMS) values of HOAs, Z(3)-1, Z(3)1, Z(4)0, Z(5)-1, Z(5)1 and Z(6)0 were analyzed. The mean RMS values for each order were higher in group 1 when compared with group 2 at 4.0 mm and 6.0 mm pupil diameters. There was no statistically significant difference between groups in spherical and coma aberrations (P > 0.05). Mean RMS values for total HOAs were 0.187 +/- 0.09 microm at 4.0 mm and 0.438 +/- 0.178 microm at 6.0 mm pupil in group 1 and 0.120 +/- 0.049 microm at 4.0 mm and 0.344 +/- 0.083 microm at 6.0 mm pupil in group 2. The difference between groups in total HOAs was statistically significant at 4.0 mm and 6.0 mm pupil diameters (P < 0.05). Ocular HOAs exist in eyes with supernormal vision. After LASEK, the amount of HOAs of the eye increases under both mesopic and photopic conditions. However the amount of HOA increase does not seem to be consistent with visual symptoms.

Shear viscosity, cavitation and hydrodynamics at LHC

International Nuclear Information System (INIS)

Bhatt, Jitesh R.; Mishra, Hiranmaya; Sreekanth, V.

2011-01-01

We study evolution of quark-gluon matter in the ultrarelativistic heavy-ion collisions within the frame work of relativistic second-order viscous hydrodynamics. In particular, by using the various prescriptions of a temperature-dependent shear viscosity to the entropy ratio, we show that the hydrodynamic description of the relativistic fluid becomes invalid due to the phenomenon of cavitation. For most of the initial conditions relevant for LHC, the cavitation sets in very early stage. The cavitation in this case is entirely driven by the large values of shear viscosity. Moreover we also demonstrate that the conformal terms used in equations of the relativistic dissipative hydrodynamic can influence the cavitation time.

A review of higher order strain gradient theories of plasticity: Origins ...

Indian Academy of Sciences (India)

require higher order boundary conditions that enable us to model effects of disloca- ..... where ǫ0 is a reference strain, σ0 the yield stress and n the strain hardening exponent. The ...... Petch N J 1953 J. Iron Steel Inst. London 173: 25. Pantleon ...

MHD stability analysis using higher order spline functions

Energy Technology Data Exchange (ETDEWEB)

Ida, Akihiro [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Nagoya, Aichi (Japan); Todoroki, Jiro; Sanuki, Heiji

1999-04-01

The eigenvalue problem of the linearized magnetohydrodynamic (MHD) equation is formulated by using higher order spline functions as the base functions of Ritz-Galerkin approximation. When the displacement vector normal to the magnetic surface (in the magnetic surface) is interpolated by B-spline functions of degree p{sub 1} (degree p{sub 2}), which is continuously c{sub 1}-th (c{sub 2}-th) differentiable on neighboring finite elements, the sufficient conditions for the good approximation is given by p{sub 1}{>=}p{sub 2}+1, c{sub 1}{<=}c{sub 2}+1, (c{sub 1}{>=}1, p{sub 2}{>=}c{sub 2}{>=}0). The influence of the numerical integration upon the convergence of calculated eigenvalues is discussed. (author)

Higher-order Multivariable Polynomial Regression to Estimate Human Affective States

Science.gov (United States)

Wei, Jie; Chen, Tong; Liu, Guangyuan; Yang, Jiemin

2016-03-01

From direct observations, facial, vocal, gestural, physiological, and central nervous signals, estimating human affective states through computational models such as multivariate linear-regression analysis, support vector regression, and artificial neural network, have been proposed in the past decade. In these models, linear models are generally lack of precision because of ignoring intrinsic nonlinearities of complex psychophysiological processes; and nonlinear models commonly adopt complicated algorithms. To improve accuracy and simplify model, we introduce a new computational modeling method named as higher-order multivariable polynomial regression to estimate human affective states. The study employs standardized pictures in the International Affective Picture System to induce thirty subjects’ affective states, and obtains pure affective patterns of skin conductance as input variables to the higher-order multivariable polynomial model for predicting affective valence and arousal. Experimental results show that our method is able to obtain efficient correlation coefficients of 0.98 and 0.96 for estimation of affective valence and arousal, respectively. Moreover, the method may provide certain indirect evidences that valence and arousal have their brain’s motivational circuit origins. Thus, the proposed method can serve as a novel one for efficiently estimating human affective states.

From "Hello" to Higher-Order Thinking: The Effect of Coaching and Feedback on Online Chats

Science.gov (United States)

Stein, David S.; Wanstreet, Constance E.; Slagle, Paula; Trinko, Lynn A.; Lutz, Michelle

2013-01-01

This exploratory study examined the effect of a coaching and feedback intervention in teaching presence and social presence on higher-order thinking in an online community of inquiry. Coaching occurred before each chat, and feedback was provided immediately afterwards. The findings suggest that over time, the frequency of higher-order thinking…

Multi-domain, higher order level set scheme for 3D image segmentation on the GPU

DEFF Research Database (Denmark)

Sharma, Ojaswa; Zhang, Qin; Anton, François

2010-01-01

to evaluate level set surfaces that are $C^2$ continuous, but are slow due to high computational burden. In this paper, we provide a higher order GPU based solver for fast and efficient segmentation of large volumetric images. We also extend the higher order method to multi-domain segmentation. Our streaming...

Predicting early academic achievement: The role of higher-versus lower-order personality traits

Directory of Open Access Journals (Sweden)

Zupančič Maja

2011-01-01

Full Text Available The study explored the role of children’s (N = 193 individual differences and parental characteristics at the beginning of the first year of schooling in predicting students’ attainment of academic standards at the end of the year. Special attention was paid to children’s personality as perceived by the teachers’ assistants. Along with parents’ education, parenting practices and first-graders’ cognitive ability, the incremental predictive power of children’s higher-order (robust personality traits was compared to the contribution of lower-order (specific traits in explaining academic achievement. The specific traits provided a somewhat more accurate prediction than the robust traits. Unique contributions of maternal authoritative parenting, children’s cognitive ability, and personality to academic achievement were established. The ratings of first-graders’ conscientiousness (a higher-order trait improved the prediction of academic achievement based on parenting and cognitive ability by 12%, whereas assistant teacher’s perceived children’s intelligence and low antagonism (lower-order traits improved the prediction by 17%.

Holographic conductivity of holographic superconductors with higher-order corrections

Energy Technology Data Exchange (ETDEWEB)

Sheykhi, Ahmad [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Ghazanfari, Afsoon; Dehyadegari, Amin [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)

2018-02-15

We analytically and numerically disclose the effects of the higher-order correction terms in the gravity and in the gauge field on the properties of s-wave holographic superconductors. On the gravity side, we consider the higher curvature Gauss-Bonnet corrections and on the gauge field side, we add a quadratic correction term to the Maxwell Lagrangian. We show that, for this system, one can still obtain an analytical relation between the critical temperature and the charge density. We also calculate the critical exponent and the condensation value both analytically and numerically. We use a variational method, based on the Sturm-Liouville eigenvalue problem for our analytical study, as well as a numerical shooting method in order to compare with our analytical results. For a fixed value of the Gauss-Bonnet parameter, we observe that the critical temperature decreases with increasing the nonlinearity of the gauge field. This implies that the nonlinear correction term to the Maxwell electrodynamics makes the condensation harder. We also study the holographic conductivity of the system and disclose the effects of the Gauss-Bonnet and nonlinear parameters α and b on the superconducting gap. We observe that, for various values of α and b, the real part of the conductivity is proportional to the frequency per temperature, ω/T, as the frequency is large enough. Besides, the conductivity has a minimum in the imaginary part which is shifted toward greater frequency with decreasing temperature. (orig.)

The higher order flux mapping method in large size PHWRs

International Nuclear Information System (INIS)

Kulkarni, A.K.; Balaraman, V.; Purandare, H.D.

1997-01-01

A new higher order method is proposed for obtaining flux map using single set of expansion mode. In this procedure, one can make use of the difference between predicted value of detector reading and their actual values for determining the strength of local fluxes around detector site. The local fluxes are arising due to constant perturbation changes (both extrinsic and intrinsic) taking place in the reactor. (author)

Connection between weighted LPC and higher-order statistics for AR model estimation

NARCIS (Netherlands)

Kamp, Y.; Ma, C.

1993-01-01

This paper establishes the relationship between a weighted linear prediction method used for robust analysis of voiced speech and the autoregressive modelling based on higher-order statistics, known as cumulants

Quantifying the impact of scholarly papers based on higher-order weighted citations.

Science.gov (United States)

Bai, Xiaomei; Zhang, Fuli; Hou, Jie; Lee, Ivan; Kong, Xiangjie; Tolba, Amr; Xia, Feng

2018-01-01

Quantifying the impact of a scholarly paper is of great significance, yet the effect of geographical distance of cited papers has not been explored. In this paper, we examine 30,596 papers published in Physical Review C, and identify the relationship between citations and geographical distances between author affiliations. Subsequently, a relative citation weight is applied to assess the impact of a scholarly paper. A higher-order weighted quantum PageRank algorithm is also developed to address the behavior of multiple step citation flow. Capturing the citation dynamics with higher-order dependencies reveals the actual impact of papers, including necessary self-citations that are sometimes excluded in prior studies. Quantum PageRank is utilized in this paper to help differentiating nodes whose PageRank values are identical.

Hamilton-Jacobi approach for first order actions and theories with higher derivatives

International Nuclear Information System (INIS)

Bertin, M.C.; Pimentel, B.M.; Pompeia, P.J.

2008-01-01

In this work, we analyze systems described by Lagrangians with higher order derivatives in the context of the Hamilton-Jacobi formalism for first order actions. Two different approaches are studied here: the first one is analogous to the description of theories with higher derivatives in the hamiltonian formalism according to [D.M. Gitman, S.L. Lyakhovich, I.V. Tyutin, Soviet Phys. J. 26 (1983) 730; D.M. Gitman, I.V. Tyutin, Quantization of Fields with Constraints, Springer-Verlag, New York, Berlin, 1990] the second treats the case where degenerate coordinate are present, in an analogy to reference [D.M. Gitman, I.V. Tyutin, Nucl. Phys. B 630 (2002) 509]. Several examples are analyzed where a comparison between both approaches is made

Compound waves in a higher order nonlinear model of thermoviscous fluids

DEFF Research Database (Denmark)

Rønne Rasmussen, Anders; Sørensen, Mads Peter; Gaididei, Yuri B.

2016-01-01

A generalized traveling wave ansatz is used to investigate compound shock waves in a higher order nonlinear model of a thermoviscous fluid. The fluid velocity potential is written as a traveling wave plus a linear function of space and time. The latter offers the possibility of predicting...

H2O2-induced higher order chromatin degradation: A novel ...

Indian Academy of Sciences (India)

Unknown

mediator of oxidative stress, can also cause genomic damage indirectly. Thus, H2O2 at pathologically relevant concentrations rapidly induces higher order chromatin degradation (HOCD), i.e. enzymatic ... clease works through a single strand scission mechanism ... a great mutagenic risk to the surviving cells, because en-.

Transition, coexistence, and interaction of vector localized waves arising from higher-order effects

International Nuclear Information System (INIS)

Liu, Chong; Yang, Zhan-Ying; Zhao, Li-Chen; Yang, Wen-Li

2015-01-01

We study vector localized waves on continuous wave background with higher-order effects in a two-mode optical fiber. The striking properties of transition, coexistence, and interaction of these localized waves arising from higher-order effects are revealed in combination with corresponding modulation instability (MI) characteristics. It shows that these vector localized wave properties have no analogues in the case without higher-order effects. Specifically, compared to the scalar case, an intriguing transition between bright–dark rogue waves and w-shaped–anti-w-shaped solitons, which occurs as a result of the attenuation of MI growth rate to vanishing in the zero-frequency perturbation region, is exhibited with the relative background frequency. In particular, our results show that the w-shaped–anti-w-shaped solitons can coexist with breathers, coinciding with the MI analysis where the coexistence condition is a mixture of a modulation stability and MI region. It is interesting that their interaction is inelastic and describes a fusion process. In addition, we demonstrate an annihilation phenomenon for the interaction of two w-shaped solitons which is identified essentially as an inelastic collision in this system. -- Highlights: •Vector rogue wave properties induced by higher-order effects are studied. •A transition between vector rogue waves and solitons is obtained. •The link between the transition and modulation instability (MI) is demonstrated. •The coexistence of vector solitons and breathers coincides with the MI features. •An annihilation phenomenon for the vector two w-shaped solitons is presented.

Transition, coexistence, and interaction of vector localized waves arising from higher-order effects

Energy Technology Data Exchange (ETDEWEB)

Liu, Chong [School of Physics, Northwest University, Xi’an 710069 (China); Yang, Zhan-Ying, E-mail: zyyang@nwu.edu.cn [School of Physics, Northwest University, Xi’an 710069 (China); Zhao, Li-Chen, E-mail: zhaolichen3@163.com [School of Physics, Northwest University, Xi’an 710069 (China); Yang, Wen-Li [Institute of Modern Physics, Northwest University, Xi’an 710069 (China)

2015-11-15

We study vector localized waves on continuous wave background with higher-order effects in a two-mode optical fiber. The striking properties of transition, coexistence, and interaction of these localized waves arising from higher-order effects are revealed in combination with corresponding modulation instability (MI) characteristics. It shows that these vector localized wave properties have no analogues in the case without higher-order effects. Specifically, compared to the scalar case, an intriguing transition between bright–dark rogue waves and w-shaped–anti-w-shaped solitons, which occurs as a result of the attenuation of MI growth rate to vanishing in the zero-frequency perturbation region, is exhibited with the relative background frequency. In particular, our results show that the w-shaped–anti-w-shaped solitons can coexist with breathers, coinciding with the MI analysis where the coexistence condition is a mixture of a modulation stability and MI region. It is interesting that their interaction is inelastic and describes a fusion process. In addition, we demonstrate an annihilation phenomenon for the interaction of two w-shaped solitons which is identified essentially as an inelastic collision in this system. -- Highlights: •Vector rogue wave properties induced by higher-order effects are studied. •A transition between vector rogue waves and solitons is obtained. •The link between the transition and modulation instability (MI) is demonstrated. •The coexistence of vector solitons and breathers coincides with the MI features. •An annihilation phenomenon for the vector two w-shaped solitons is presented.

In-Service Teacher Education: Asking Questions for Higher Order Thinking in Visual Literacy

Science.gov (United States)

Moodley, Visvaganthie

2013-01-01

The kinds of questions teachers ask may thwart or promote learner high-order thinking; teachers themselves must have expertise in questioning skills to promote higher order cognition among learners. Drawing on experiential knowledge of assessment, and as an English-teaching professional development programme (PDP) facilitator, I demonstrate that…

The Relationship between Higher Order Thinking Skills and Academic Performance of Student in Mathematics Instruction

Science.gov (United States)

Tanujaya, Benidiktus; Mumu, Jeinne; Margono, Gaguk

2017-01-01

Higher order thinking skills (HOTS) is one of important aspects in education. Students with high level of higher order thinking skills tend to be more successful. However, do this phenomenon also happen in the learning of Mathematics? To answer this question, this research aims to study the relationship between HOTS and students' academic…

Influence of Pressure-gradient and Shear on Ballooning Stability in Stellarators

International Nuclear Information System (INIS)

Hudson, S.R.; Hegna, C.C.; Nakajima, N.

2005-01-01

Pressure-driven, ideal ballooning stability calculations are often used to predict the achievable plasma in stellarator configurations. In this paper, the sensitivity of ballooning stability to plasmas profile variations is addressed. A simple, semi-analytic method for expressing the ballooning growth rate, for each field line, as a polynomial function of the variation in the pressure gradient and the average magnetic shear from an original equilibrium has recently been introduced [Phys. Plasmas 11:9 (September 2004) L53]. This paper will apply the expression to various stellarator configurations and comment on the validity of various truncated forms of the polynomial expression. In particular, it is shown that in general it is insufficient to consider only the second order terms as previously assumed, and that higher order terms must be included to obtain accurate predictions of stability

Shear modulation experiments with ECCD on TCV

International Nuclear Information System (INIS)

Cirant, S.; Alberti, S.; Gandini, F.; Behn, R.; Goodman, T.P.; Nikkola, P.

2006-01-01

Anomalous electron transport is determined by turbulence, which in turn is affected by magnetic shear. A novel application of electron cyclotron current drive (ECCD), aiming at localized shear modulation, has been applied on the TCV tokamak for experiments on shear-dependent electron transport. Pairs of EC beams, absorbed at the same radius, with one oriented for co- and the other for counter-injection, are modulated out of phase in order to force a local modulation of current-density at constant input power. Off-axis deposition (ρ dep = 0.24) is performed to avoid the central region, where the low heat flux would make transport analysis difficult. In addition some sawteeth control is achieved in this way. A significant impact on local shear is achieved with I ECCD ∼ 0.1I OH , even when the modulation period is much shorter than the current diffusion time across the whole plasma radius. The main result is that although source (heat and particle) terms are constant, both electron density and temperature are modulated during alternated ECCD. Once equilibrium effects are taken into account for appropriate mapping of Thomson scattering measurements onto flux coordinates, modulation of T e and electron pressure, peaked on-axis, is confirmed at all radii internal to EC deposition. The best confinement occurs for co-injection, in which case a local decrease (∼55%) in the magnetic shear causes a decrease in the electron thermal diffusivity of a similar amount (∼65%)

Higher-order geodesic deviation for charged particles and resonance induced by gravitational waves

Science.gov (United States)

Heydari-Fard, M.; Hasani, S. N.

We generalize the higher-order geodesic deviation for the structure-less test particles to the higher-order geodesic deviation equations of the charged particles [R. Kerner, J. W. van Holten and R. Colistete Jr., Class. Quantum Grav. 18 (2001) 4725]. By solving these equations for charged particles moving in a constant magnetic field in the spacetime of a gravitational wave, we show for both cases when the gravitational wave is parallel and perpendicular to the constant magnetic field, a magnetic resonance appears at wg = Ω. This feature might be useful to detect the gravitational wave with high frequencies.

Higher order mode analysis of the SNS superconducting linac

CERN Document Server

Sang Ho Kim; Dong Jeon; Sundelin, R

2001-01-01

Higher order modes (HOM's) of monopoles, dipoles, quadrupoles and sextupoles in beta =0.61 and beta =0.81 6-cell superconducting (SC) cavities for the Spallation Neutron Source (SNS) project, have been found up to about 3 GHz and their properties such as R/Q, trapping possibility, etc have been figured out concerning manufacturing imperfection. The main issues of HOM's are beam instabilities (published separately) and HOM induced power especially from TM monopoles. The time structure of SNS beam has three different time scales of pulses, which are micro-pulse, midi-pulse and macropulse. Each time structure will generate resonances. When a mode is near these resonance frequencies, the induced voltage could be large and accordingly the resulting HOM power. In order to understand the effects from such a complex beam time structure on the mode excitation and resulting HOM power, analytic expressions are developed. With these analytic expressions, the induced HOM voltage and HOM power were calculated by assuming e...

Correlated stopping, proton clusters and higher order proton cumulants

Energy Technology Data Exchange (ETDEWEB)

Bzdak, Adam [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow (Poland); Koch, Volker [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Skokov, Vladimir [RIKEN/BNL, Brookhaven National Laboratory, Upton, NY (United States)

2017-05-15

We investigate possible effects of correlations between stopped nucleons on higher order proton cumulants at low energy heavy-ion collisions. We find that fluctuations of the number of wounded nucleons N{sub part} lead to rather nontrivial dependence of the correlations on the centrality; however, this effect is too small to explain the large and positive four-proton correlations found in the preliminary data collected by the STAR collaboration at √(s) = 7.7 GeV. We further demonstrate that, by taking into account additional proton clustering, we are able to qualitatively reproduce the preliminary experimental data. We speculate that this clustering may originate either from collective/multi-collision stopping which is expected to be effective at lower energies or from a possible first-order phase transition, or from (attractive) final state interactions. To test these ideas we propose to measure a mixed multi-particle correlation between stopped protons and a produced particle (e.g. pion, antiproton). (orig.)

Higher-order Nielsen numbers

Directory of Open Access Journals (Sweden)

Saveliev Peter

2005-01-01

Full Text Available Suppose , are manifolds, are maps. The well-known coincidence problem studies the coincidence set . The number is called the codimension of the problem. More general is the preimage problem. For a map and a submanifold of , it studies the preimage set , and the codimension is . In case of codimension , the classical Nielsen number is a lower estimate of the number of points in changing under homotopies of , and for an arbitrary codimension, of the number of components of . We extend this theory to take into account other topological characteristics of . The goal is to find a "lower estimate" of the bordism group of . The answer is the Nielsen group defined as follows. In the classical definition, the Nielsen equivalence of points of based on paths is replaced with an equivalence of singular submanifolds of based on bordisms. We let , then the Nielsen group of order is the part of preserved under homotopies of . The Nielsen number of order is the rank of this group (then . These numbers are new obstructions to removability of coincidences and preimages. Some examples and computations are provided.

Analyzes of students’ higher-order thinking skills of heat and temperature concept

Science.gov (United States)

Slamet Budiarti, Indah; Suparmi, A.; Sarwanto; Harjana

2017-11-01

High order thinking skills refer to three highest domains of the revised Bloom Taxonomy. The aims of the research were to analyze the student’s higher-order thinking skills of heat and temperature concept. The samples were taken by purposive random sampling technique consisted of 85 high school students from 3 senior high schools in Jayapura city. The descriptive qualitative method was employed in this study. The data were collected by using tests and interviews regarding the subject matters of heat and temperature. Based on the results of data analysis, it was concluded that 68.24% of the students have a high order thinking skills in the analysis, 3.53% of the students have a high order thinking skills in evaluating, and 0% of the students have a high order thinking skills in creation.

Interlayer shear of nanomaterials: Graphene-graphene, boron nitride-boron nitride and graphene-boron nitride

Institute of Scientific and Technical Information of China (English)

Yinfeng Li; Weiwei Zhang; Bill Guo; Dibakar Datta

2017-01-01

In this paper,the interlayer sliding between graphene and boron nitride (h-BN) is studied by molecular dynamics simulations.The interlayer shear force between h-BN/h-BN is found to be six times higher than that of graphene/graphene,while the interlayer shear between graphene/h-BN is approximate to that of graphene/graphene.The graphene/h-BN heterostructure shows several anomalous interlayer shear characteristics compared to its bilayer counterparts.For graphene/graphene and h-BN/h-BN,interlayer shears only exit along the sliding direction while interlayer shear for graphene/h-BN is observed along both the translocation and perpendicular directions.Our results provide significant insight into the interlayer shear characteristics of 2D nanomaterials.

Design Against Propagating Shear Failure in Pipelines

Science.gov (United States)

Leis, B. N.; Gray, J. Malcolm

Propagating shear failure can occur in gas and certain hazardous liquid transmission pipelines, potentially leading to a large long-burning fire and/or widespread pollution, depending on the transported product. Such consequences require that the design of the pipeline and specification of the steel effectively preclude the chance of propagating shear failure. Because the phenomenology of such failures is complex, design against such occurrences historically has relied on full-scale demonstration experiments coupled with empirically calibrated analytical models. However, as economic drivers have pushed toward larger diameter higher pressure pipelines made of tough higher-strength grades, the design basis to ensure arrest has been severely compromised. Accordingly, for applications where the design basis becomes less certain, as has occurred increasing as steel grade and toughness has increased, it has become necessary to place greater reliance on the use and role of full-scale testing.

Development of a shear force measurement dummy for seat comfort.

Science.gov (United States)

Kim, Seong Guk; Ko, Chang-Yong; Kim, Dong Hyun; Song, Ye Eun; Kang, Tae Uk; Ahn, Sungwoo; Lim, Dohyung; Kim, Han Sung

2017-01-01

Seat comfort is one of the main factors that consumers consider when purchasing a car. In this study, we develop a dummy with a shear-force sensor to evaluate seat comfort. The sensor has dimensions of 25 mm × 25 mm × 26 mm and is made of S45C. Electroless nickel plating is employed to coat its surface in order to prevent corrosion and oxidation. The proposed sensor is validated using a qualified load cell and shows high accuracy and precision (measurement range: -30-30 N; sensitivity: 0.1 N; linear relationship: R = 0.999; transverse sensitivity: <1%). The dummy is manufactured in compliance with the SAE standards (SAE J826) and incorporates shear sensors into its design. We measure the shear force under four driving conditions and at five different speeds using a sedan; results showed that the shear force increases with speed under all driving conditions. In the case of acceleration and deceleration, shear force significantly changes in the lower body of the dummy. During right and left turns, it significantly changes in the upper body of the dummy.

Alignment of learning objectives and assessments in therapeutics courses to foster higher-order thinking.

Science.gov (United States)

FitzPatrick, Beverly; Hawboldt, John; Doyle, Daniel; Genge, Terri

2015-02-17

To determine whether national educational outcomes, course objectives, and classroom assessments for 2 therapeutics courses were aligned for curricular content and cognitive processes, and if they included higher-order thinking. Document analysis and student focus groups were used. Outcomes, objectives, and assessment tasks were matched for specific therapeutics content and cognitive processes. Anderson and Krathwohl's Taxonomy was used to define higher-order thinking. Students discussed whether assessments tested objectives and described their thinking when responding to assessments. There were 7 outcomes, 31 objectives, and 412 assessment tasks. The alignment for content and cognitive processes was not satisfactory. Twelve students participated in the focus groups. Students thought more short-answer questions than multiple choice questions matched the objectives for content and required higher-order thinking. The alignment analysis provided data that could be used to reveal and strengthen the enacted curriculum and improve student learning.

Shape invariant higher-order Bessel-like beams carrying orbital angular momentum

CSIR Research Space (South Africa)

Ismail, Y

2012-09-01

Full Text Available -1 Journal of Optics September 2012/ Vol. 14 Shape invariant higher-order Bessel-like beams carrying orbital angular momentum Y Ismail1,2, N Khilo3, V Belyi3 and A Forbes1,2 1 School of Physics, University of KwaZulu-Natal, Private Bag X54001...

Quantifying the impact of scholarly papers based on higher-order weighted citations

Science.gov (United States)

Bai, Xiaomei; Zhang, Fuli; Hou, Jie; Kong, Xiangjie; Tolba, Amr; Xia, Feng

2018-01-01

Quantifying the impact of a scholarly paper is of great significance, yet the effect of geographical distance of cited papers has not been explored. In this paper, we examine 30,596 papers published in Physical Review C, and identify the relationship between citations and geographical distances between author affiliations. Subsequently, a relative citation weight is applied to assess the impact of a scholarly paper. A higher-order weighted quantum PageRank algorithm is also developed to address the behavior of multiple step citation flow. Capturing the citation dynamics with higher-order dependencies reveals the actual impact of papers, including necessary self-citations that are sometimes excluded in prior studies. Quantum PageRank is utilized in this paper to help differentiating nodes whose PageRank values are identical. PMID:29596426

An initial framework for the language of higher-order thinking mathematics practices

Science.gov (United States)

Staples, Megan E.; Truxaw, Mary P.

2012-09-01

This article presents an examination of the language demands of cognitively demanding tasks and proposes an initial framework for the language demands of higher-order mathematics thinking practices. We articulate four categories for this framework: language of generalisation, language of comparison, language of proportional reasoning, and language of analysing impact. These categories were developed out of our collaborative work to design and implement higher-order thinking tasks with a group of Grade 9 (14- and 15-year-olds) teachers teaching in a linguistically diverse setting; analyses of student work samples on these tasks; and our knowledge of the literature. We describe each type of language demand and then analyse student work in each category to reveal linguistic challenges facing students as they engage these mathematical tasks. Implications for teaching and professional development are discussed.

Pairwise and higher-order correlations among drug-resistance mutations in HIV-1 subtype B protease

Directory of Open Access Journals (Sweden)

Morozov Alexandre V

2009-08-01

Full Text Available Abstract Background The reaction of HIV protease to inhibitor therapy is characterized by the emergence of complex mutational patterns which confer drug resistance. The response of HIV protease to drugs often involves both primary mutations that directly inhibit the action of the drug, and a host of accessory resistance mutations that may occur far from the active site but may contribute to restoring the fitness or stability of the enzyme. Here we develop a probabilistic approach based on connected information that allows us to study residue, pair level and higher-order correlations within the same framework. Results We apply our methodology to a database of approximately 13,000 sequences which have been annotated by the treatment history of the patients from which the samples were obtained. We show that including pair interactions is essential for agreement with the mutational data, since neglect of these interactions results in order-of-magnitude errors in the probabilities of the simultaneous occurence of many mutations. The magnitude of these pair correlations changes dramatically between sequences obtained from patients that were or were not exposed to drugs. Higher-order effects make a contribution of as much as 10% for residues taken three at a time, but increase to more than twice that for 10 to 15-residue groups. The sequence data is insufficient to determine the higher-order effects for larger groups. We find that higher-order interactions have a significant effect on the predicted frequencies of sequences with large numbers of mutations. While relatively rare, such sequences are more prevalent after multi-drug therapy. The relative importance of these higher-order interactions increases with the number of drugs the patient had been exposed to. Conclusion Correlations are critical for the understanding of mutation patterns in HIV protease. Pair interactions have substantial qualitative effects, while higher-order interactions are

Shear Adhesion of Tapered Nanopillar Arrays.

Science.gov (United States)

Cho, Younghyun; Minsky, Helen K; Jiang, Yijie; Yin, Kaiyang; Turner, Kevin T; Yang, Shu

2018-04-04

Tapered nanopillars with various cross sections, including cone-shaped, stepwise, and pencil-like structures (300 nm in diameter at the base of the pillars and 1.1 μm in height), are prepared from epoxy resin templated by nanoporous anodic aluminum oxide (AAO) membranes. The effect of pillar geometry on the shear adhesion behavior of these nanopillar arrays is investigated via sliding experiments in a nanoindentation system. In a previous study of arrays with the same geometry, it was shown that cone-shaped nanopillars exhibit the highest adhesion under normal loading while stepwise and pencil-like nanopillars exhibit lower normal adhesion strength due to significant deformation of the pillars that occurs with increasing indentation depth. Contrary to the previous studies, here, we show that pencil-like nanopillars exhibit the highest shear adhesion strength at all indentation depths among three types of nanopillar arrays and that the shear adhesion increases with greater indentation depth due to the higher bending stiffness and closer packing of the pencil-like nanopillar array. Finite element simulations are used to elucidate the deformation of the pillars during the sliding experiments and agree with the nanoindentation-based sliding measurements. The experiments and finite element simulations together demonstrate that the shape of the nanopillars plays a key role in shear adhesion and that the mechanism is quite different from that of adhesion under normal loading.

General relativity and gauge gravity theories of higher order

International Nuclear Information System (INIS)

Konopleva, N.P.

1998-01-01

It is a short review of today's gauge gravity theories and their relations with Einstein General Relativity. The conceptions of construction of the gauge gravity theories with higher derivatives are analyzed. GR is regarded as the gauge gravity theory corresponding to the choice of G ∞4 as the local gauge symmetry group and the symmetrical tensor of rank two g μν as the field variable. Using the mathematical technique, single for all fundamental interactions (namely variational formalism for infinite Lie groups), we can obtain Einstein's theory as the gauge theory without any changes. All other gauge approaches lead to non-Einstein theories of gravity. But above-mentioned mathematical technique permits us to construct the gauge gravity theory of higher order (for instance SO (3,1)-gravity) so that all vacuum solutions of Einstein equations are the solutions of the SO (3,1)-gravity theory. The structure of equations of SO(3,1)-gravity becomes analogous to Weeler-Misner geometrodynamics one

Continuous shear - a method for studying material elements passing a stationary shear plane

DEFF Research Database (Denmark)

Lindegren, Maria; Wiwe, Birgitte; Wanheim, Tarras

2003-01-01

circumferential groove. Normally shear in metal forming processes is of another nature, namely where the material elements move through a stationary shear zone, often of small width. In this paper a method enabling the simulation of this situation is presented. A tool for continuous shear has beeen manufactured...... and tested with AlMgSil and copper. The sheared material has thereafter been tested n plane strain compression with different orientation concerning the angle between the shear plane and the compression direction....

EMHD micro-pumping of a non-conducting shear-thinning fluid under EDL phenomena

International Nuclear Information System (INIS)

Gaikwad, Harshad; Borole, Chetan; Basu, Dipankar N.; Mondal, Pranab K.

2016-01-01

The Electro-Magneto-Hydrodynamic (EMHD) pumping of a binary fluid system constituted by one non-conducting shear-thinning fluid (top layer) by exploiting the transverse momentum exchange through the interfacial viscous shearing effect from a conducting Newtonian fluid layer (bottom layer) in a microfluidic channel is investigated. An externally applied electric field drives the conducting fluid layer under the influence of an applied magnetic field as well. The study reveals that the volume transport of shear-thinning fluid gets augmented for low magnetic field strength, higher electrical double layer (EDL) effect, low viscosity ratio and moderate potential ratio. It is also established that the volumetric flow rate reduces significantly for the higher magnetic field strength. (author)

On the behaviour of gelled fibre suspensions in steady shear

Energy Technology Data Exchange (ETDEWEB)

Wolf, Bettina [Unilever Corporate Research, Bedford (United Kingdom); University of Nottingham, Division of Food Sciences, Loughborough (United Kingdom); White, Duncan; Melrose, John R.; Frith, William J. [Unilever Corporate Research, Bedford (United Kingdom)

2007-03-15

The shear rheological properties of suspensions of gelled agar fibres in a low viscosity Newtonian matrix fluid were investigated. Two classes of fibres, low aspect ratio fibres and high aspect ratio fibres with an aspect ratio of the order of 10 and 100 respectively were included in the investigations. For all fibre phase volumes investigated, from as low as 0.01 upwards, the flow curves are characterised by an apparent yield stress followed by shear-thinning which was independent of the fibre aspect ratio. Based on our analysis of the flow curves, we conclude that the high aspect ratio fibres behave like flexible threads in contrast to the low aspect ratio fibres whose high shear relative viscosity is successfully described by a relation for long rigid rods. These findings are supported by flow visualisation using an optical shearing stage coupled to a light microscope. (orig.)

Impact of higher-order flows in the moment equations on Pfirsch-Schlüter friction coefficients

Energy Technology Data Exchange (ETDEWEB)

Honda, M., E-mail: honda.mitsuru@jaea.go.jp [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)

2014-09-15

The impact of the higher-order flows in the moment approach on an estimate of the friction coefficients is numerically examined. The higher-order flows are described by the lower-order hydrodynamic flows using the collisional plasma assumption. Their effects have not been consistently taken into account thus far in the widely used neoclassical transport codes based on the moment equations in terms of the Pfirsch-Schlüter flux. Due to numerically solving the friction-flow matrix without using the small-mass ratio expansion, it is clearly revealed that incorporating the higher-order flow effects is of importance especially for plasmas including multiple hydrogenic ions and other lighter species with similar masses.

Role of low order rational q-values in the ITB events in JT-60U reverse shear plasmas

International Nuclear Information System (INIS)

Neudatchin, S.V.; Takizuka, T.; Hayashi, N.; Isayama, A.; Shirai, H.; Fujita, T.; Kamada, Y.; Koide, Y.; Suzuki, T.

2004-01-01

Non-local confinement bifurcations inside and around internal transport barriers (ITBs) with a ms timescale (ITB events) have previously been found in JT-60U reverse shear (RS) and high-β p plasmas. ITB events are observed as the simultaneous rise and decay of T e in two zones. They are created by an abrupt non-local reduction (or increase) of heat flux inside 30-40% of the minor radius. Under sufficient neutral beam power P nbi (above ∼8 MW for the 1.2-1.5 MA/3.8 T pulses described below), ITB events were previously detected at various q min values. However, the role of q min equal to 3.5, 3, 2.5, 2 is not obvious for ITB formation. In this paper, we focus on new features of ITB evolution near low-order-rational values of q min . The formation of a stronger ITB and its further splitting into two radially separated ITBs is described. These ITBs are located in both positive and negative shear zones of a plasma with L-mode edge. The similarity of space-time evolution of T e and T i at sufficient power is highlighted (even when the variation is significant and complicated in space and time). Within error-bars, ITB splitting occurs as q min passes through 2.5. The similarity of space-time evolution of T e and T i suggests a similarity in the qualitative behaviour of electron and ion heat diffusivities in time and space. The temporal formation of an ITB in the zone with small positive shear, while q min passes through 3 (after periodical improvements and degradations via ITB events with 8 ms period) in H-mode, with P nbi = 8 MW, is described. At lower powers, ITB events are observed only near rational values of q min . In weak RS shots with P nbi = 4 MW, transport is reduced via ITB events during 0.08 s at q min = 3.5, and repetitive short-term phases of reduced transport are observed as q min passes through 3. The behaviour of T i looks different. The difference in T e and T i evolution, which was detected regularly under low power, probably indicates a decoupling

Quasi-static and dynamic forced shear deformation behaviors of Ti-5Mo-5V-8Cr-3Al alloy

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhiming; Chen, Zhiyong, E-mail: czysh@netease.com; Zhan, Congkun; Kuang, Lianjun; Shao, Jianbo; Wang, Renke; Liu, Chuming

2017-04-13

The mechanical behavior and microstructure characteristics of Ti-5Mo-5V-8Cr-3Al alloy were investigated with hat-shaped samples compressed under quasi-static and dynamic loading. Compared with the quasi-static loading, a higher shear stress peak and a shear instability stage were observed during the dynamic shear response. The results showed that an adiabatic shear band consisting of ultrafine equiaxed grains was only developed in the dynamic specimen, while a wider shear region was formed in the quasi-static specimen. The microhardness measurements revealed that shear region in the quasi-static specimen and adiabatic shear band in the dynamic specimen exhibited higher hardness than that of adjacent regions due to the strain hardening and grain refining, respectively. A stable orientation, in which the crystallographic {110} planes and <111> directions were respectively parallel to the shear plane and shear direction, developed in both specimens. And the microtexture of the adiabatic shear band was more well-defined than that of the shear region in the quasi-static specimen. Rotational dynamic recrystallization mechanism was suggested to explain the formation of ultrafine equiaxed grains within the adiabatic shear band by thermodynamic and kinetic calculations.

Limit cycles via higher order perturbations for some piecewise differential systems

Science.gov (United States)

Buzzi, Claudio A.; Lima, Maurício Firmino Silva; Torregrosa, Joan

2018-05-01

A classical perturbation problem is the polynomial perturbation of the harmonic oscillator, (x‧ ,y‧) =(- y + εf(x , y , ε) , x + εg(x , y , ε)) . In this paper we study the limit cycles that bifurcate from the period annulus via piecewise polynomial perturbations in two zones separated by a straight line. We prove that, for polynomial perturbations of degree n , no more than Nn - 1 limit cycles appear up to a study of order N. We also show that this upper bound is reached for orders one and two. Moreover, we study this problem in some classes of piecewise Liénard differential systems providing better upper bounds for higher order perturbation in ε, showing also when they are reached. The Poincaré-Pontryagin-Melnikov theory is the main technique used to prove all the results.

Higher Order Thinking in the Australian Army Suite of Logistic Officer Courses

National Research Council Canada - National Science Library

Bradford, Scott R

2006-01-01

.... The current Suite of Logistic Officer Courses (SOLOC) has been recently criticized for failing to meet this requirement, with the general perception that there is a distinct lack of higher-order thinking competencies within this continuum...

Biofouling of reverse-osmosis membranes under different shear rates during tertiary wastewater desalination: microbial community composition.

Science.gov (United States)

Al Ashhab, Ashraf; Gillor, Osnat; Herzberg, Moshe

2014-12-15

We investigated the influence of feed-water shear rate during reverse-osmosis (RO) desalination on biofouling with respect to microbial community composition developed on the membrane surface. The RO membrane biofilm's microbial community profile was elucidated during desalination of tertiary wastewater effluent in a flat-sheet lab-scale system operated under high (555.6 s(-1)), medium (370.4 s(-1)), or low (185.2 s(-1)) shear rates, corresponding to average velocities of 27.8, 18.5, and 9.3 cm s(-1), respectively. Bacterial diversity was highest when medium shear was applied (Shannon-Weaver diversity index H' = 4.30 ± 0.04) compared to RO-membrane biofilm developed under lower and higher shear rates (H' = 3.80 ± 0.26 and H' = 3.42 ± 0.38, respectively). At the medium shear rate, RO-membrane biofilms were dominated by Betaproteobacteria, whereas under lower and higher shear rates, the biofilms were dominated by Alpha- and Gamma- Proteobacteria, and the latter biofilms also contained Deltaproteobacteria. Bacterial abundance on the RO membrane was higher at low and medium shear rates compared to the high shear rate: 8.97 × 10(8) ± 1.03 × 10(3), 4.70 × 10(8) ± 1.70 × 10(3) and 5.72 × 10(6) ± 2.09 × 10(3) copy number per cm(2), respectively. Interestingly, at the high shear rate, the RO-membrane biofilm's bacterial community consisted mainly of populations known to excrete high amounts of extracellular polymeric substances. Our results suggest that the RO-membrane biofilm's community composition, structure and abundance differ in accordance with applied shear rate. These results shed new light on the biofouling phenomenon and are important for further development of antibiofouling strategies for RO membranes. Copyright © 2014 Elsevier Ltd. All rights reserved.

A higher-order numerical framework for stochastic simulation of chemical reaction systems.

KAUST Repository

Székely, Tamás

2012-07-15

BACKGROUND: In this paper, we present a framework for improving the accuracy of fixed-step methods for Monte Carlo simulation of discrete stochastic chemical kinetics. Stochasticity is ubiquitous in many areas of cell biology, for example in gene regulation, biochemical cascades and cell-cell interaction. However most discrete stochastic simulation techniques are slow. We apply Richardson extrapolation to the moments of three fixed-step methods, the Euler, midpoint and θ-trapezoidal τ-leap methods, to demonstrate the power of stochastic extrapolation. The extrapolation framework can increase the order of convergence of any fixed-step discrete stochastic solver and is very easy to implement; the only condition for its use is knowledge of the appropriate terms of the global error expansion of the solver in terms of its stepsize. In practical terms, a higher-order method with a larger stepsize can achieve the same level of accuracy as a lower-order method with a smaller one, potentially reducing the computational time of the system. RESULTS: By obtaining a global error expansion for a general weak first-order method, we prove that extrapolation can increase the weak order of convergence for the moments of the Euler and the midpoint τ-leap methods, from one to two. This is supported by numerical simulations of several chemical systems of biological importance using the Euler, midpoint and θ-trapezoidal τ-leap methods. In almost all cases, extrapolation results in an improvement of accuracy. As in the case of ordinary and stochastic differential equations, extrapolation can be repeated to obtain even higher-order approximations. CONCLUSIONS: Extrapolation is a general framework for increasing the order of accuracy of any fixed-step stochastic solver. This enables the simulation of complicated systems in less time, allowing for more realistic biochemical problems to be solved.

Development of Generalized Correlation Equation for the Local Wall Shear Stress

International Nuclear Information System (INIS)

Jeon, Yu Mi; Park, Ju Hwan

2010-06-01

The pressure drop characteristics for a fuel channel are essential for the design and reliable operation of a nuclear reactor. Over several decades, analytical methods have been developed to predict the friction factor in the fuel bundle flows. In order to enhance the accuracy of prediction for the pressure drop in a rod bundle, the influences of a channel wall and the local shear stress distribution should be considered. Therefore, the correlation equation for a local wall shear stress distribution should be developed in order to secure an analytical solution for the friction factor of a rod bundle. For a side subchannel, which has the influence of the channel wall, the local wall shear stress distribution is dependent on the ratio of wall to diameter (W/D) as well as the ratio of pitch to diameter (P/D). In the case that W/D has the same value with P/D, the local shear stress distribution can be simply correlated with the function of angular position for each value of P/D. While in the case where W/D has a different value than P/D, the correlation equation should be developed for each case of P/D and W/D. Therefore, in the present study, the generalized correlation equation of the local wall shear stress distribution was developed for a side subchannel in the case where W/D has a different value than P/D. Consequently, the generalized correlation equation of a local wall shear stress distribution can be represented by the equivalent pitch to diameter ratio, P'/D for the case that P/D and W/D had a different value

Growth of meromorphic solutions of higher-order linear differential equations

Directory of Open Access Journals (Sweden)

Wenjuan Chen

2009-01-01

Full Text Available In this paper, we investigate the higher-order linear differential equations with meromorphic coefficients. We improve and extend a result of M.S. Liu and C.L. Yuan, by using the estimates for the logarithmic derivative of a transcendental meromorphic function due to Gundersen, and the extended Winman-Valiron theory which proved by J. Wang and H.X. Yi. In addition, we also consider the nonhomogeneous linear differential equations.

Higher order temporal finite element methods through mixed formalisms.

Science.gov (United States)

Kim, Jinkyu

2014-01-01

The extended framework of Hamilton's principle and the mixed convolved action principle provide new rigorous weak variational formalism for a broad range of initial boundary value problems in mathematical physics and mechanics. In this paper, their potential when adopting temporally higher order approximations is investigated. The classical single-degree-of-freedom dynamical systems are primarily considered to validate and to investigate the performance of the numerical algorithms developed from both formulations. For the undamped system, all the algorithms are symplectic and unconditionally stable with respect to the time step. For the damped system, they are shown to be accurate with good convergence characteristics.

Higher-order processes in x-ray photoionization of atoms

International Nuclear Information System (INIS)

Kanter, E. P.; Dunford, R. W.; Krassig, B.; Southworth, S. H.; Young, L.

2006-01-01

There are several fourth-generation X-ray light source projects now underway around the world and it is anticipated that by the end of the decade, one or more of these X-ray free-electron lasers will be operational. In this contribution, we describe recent measurements and future plans to study both multielectron and multiphoton atomic photoionization. Although such higher-order processes are rare with present third-generation sources, they will be commonplace in experimental work with the new sources. The topics we discuss here are double K-shell ionization and two-photon X-ray photoionization

Dynamic shear stabilization of hydromagnetic instabilities in low-beta plasma column by a frequency near the ion cyclotron frequency

International Nuclear Information System (INIS)

Minami, Kazuo; Sato, Kazunori.

1978-09-01

The dynamic shear stabilization of the hydromagnetic instability in low-beta plasmas by an axial RF current whose frequency is not much smaller than the ion cyclotron frequency ωsub(ci) is analyzed in some detail. We adopt the simple model of a uniform plasma column with infinite conductivity. Attention is limited to the case of the m = 1 kink mode with long wave lengths. The Mathieu equation, in which the effect of the ion cyclotron motion is taken into account, is derived. It is shown that the dynamic shear stabilization is still effective, even if the frequency of the applied RF current is of the order of ωsub(ci), which is considerably higher than the frequencies believed to be available in the previous analyses. (author)

Development of generalized correlation equation for the local wall shear stress

International Nuclear Information System (INIS)

Jeon, Yu Mi; Bae, Jun Ho; Park, Joo Hwan

2010-01-01

The pressure drop characteristics for a fuel channel are essential for the design and reliable operation of a nuclear reactor. Over several decades, analytical methods have been developed to predict the friction factor in the fuel bundle flows. In order to enhance the accuracy of prediction for the pressure drop in a rod bundle, the influences of a channel wall and the local shear stress distribution should be considered. Hence, the correlation equation for a local shear stress distribution should be developed in order to secure an analytical solution for the friction factor of a rod bundle. For a side subchannel, which has the influence of the channel wall, the local shear stress distribution is dependent on the ratio of wall to diameter (W/D) as well as the ratio of pitch to diameter (P/D). In the case that W/D has the same value with P/D, the local shear stress distribution can be simply correlated with the function of angular position for each value of P/D. While, in the case that W/D has the different value with P/D, the correlation equation should be developed for each case of P/D and W/D. Hence, in the present study, the generalized correlation equation of a local shear stress distribution is developed for a side subchannel in the case that W/D has the different value with P/D

A Frank mixture copula family for modeling higher-order correlations of neural spike counts

International Nuclear Information System (INIS)

Onken, Arno; Obermayer, Klaus

2009-01-01

In order to evaluate the importance of higher-order correlations in neural spike count codes, flexible statistical models of dependent multivariate spike counts are required. Copula families, parametric multivariate distributions that represent dependencies, can be applied to construct such models. We introduce the Frank mixture family as a new copula family that has separate parameters for all pairwise and higher-order correlations. In contrast to the Farlie-Gumbel-Morgenstern copula family that shares this property, the Frank mixture copula can model strong correlations. We apply spike count models based on the Frank mixture copula to data generated by a network of leaky integrate-and-fire neurons and compare the goodness of fit to distributions based on the Farlie-Gumbel-Morgenstern family. Finally, we evaluate the importance of using proper single neuron spike count distributions on the Shannon information. We find notable deviations in the entropy that increase with decreasing firing rates. Moreover, we find that the Frank mixture family increases the log likelihood of the fit significantly compared to the Farlie-Gumbel-Morgenstern family. This shows that the Frank mixture copula is a useful tool to assess the importance of higher-order correlations in spike count codes.

Cultivation of shear stress sensitive microorganisms in disposable bag reactor systems.

Science.gov (United States)

Jonczyk, Patrick; Takenberg, Meike; Hartwig, Steffen; Beutel, Sascha; Berger, Ralf G; Scheper, Thomas

2013-09-20

Technical scale (≥5l) cultivations of shear stress sensitive microorganisms are often difficult to perform, as common bioreactors are usually designed to maximize the oxygen input into the culture medium. This is achieved by mechanical stirrers, causing high shear stress. Examples for shear stress sensitive microorganisms, for which no specific cultivation systems exist, are many anaerobic bacteria and fungi, such as basidiomycetes. In this work a disposable bag bioreactor developed for cultivation of mammalian cells was investigated to evaluate its potential to cultivate shear stress sensitive anaerobic Eubacterium ramulus and shear stress sensitive basidiomycetes Flammulina velutipes and Pleurotus sapidus. All cultivations were compared with conventional stainless steel stirred tank reactors (STR) cultivations. Good growth of all investigated microorganisms cultivated in the bag reactor was found. E. ramulus showed growth rates of μ=0.56 h⁻¹ (bag) and μ=0.53 h⁻¹ (STR). Differences concerning morphology, enzymatic activities and growth in fungal cultivations were observed. In the bag reactor growth in form of small, independent pellets was observed while STR cultivations showed intense aggregation. F. velutipes reached higher biomass concentrations (21.2 g l⁻¹ DCW vs. 16.8 g l⁻¹ DCW) and up to 2-fold higher peptidolytic activities in comparison to cell cultivation in stirred tank reactors. Copyright © 2013 Elsevier B.V. All rights reserved.

Shear layer flame stabilization sensitivities in a swirling flow

Directory of Open Access Journals (Sweden)

Christopher Foley

2017-03-01

Full Text Available A variety of different flame configurations and heat release distributions exist in high swirl, annular flows, due to the existence of inner and outer shear layers as well a vortex breakdown bubble. Each of these different configurations, in turn, has different thermoacoustic sensitivities and influences on combustor emissions, nozzle durability, and liner heating. This paper presents findings on the sensitivities of the outer shear layer- stabilized flames to a range of parameters, including equivalence ratio, bulkhead temperature, flow velocity, and preheat temperature. There is significant hysteresis for flame attachment/detachment from the outer shear layer and this hysteresis is also described. Results are also correlated with extinction stretch rate calculations based on detailed kinetic simulations. In addition, we show that the bulkhead temperature near the flame attachment point has significant impact on outer shear layer detachment. This indicates that understanding the heat transfer between the edge flame stabilized in the shear layer and the nozzle hardware is needed in order to predict shear layer flame stabilization limits. Moreover, it shows that simulations cannot simply assume adiabatic boundary conditions if they are to capture these transitions. We also show that the reference temperature for correlating these transitions is quite different for attachment and local blow off. Finally, these results highlight the deficiencies in current understanding of the influence of fluid mechanic parameters (e.g. velocity, swirl number on shear layer flame attachment. For example, they show that the seemingly simple matter of scaling flame transition points with changes in flow velocities is not understood.

Solidification of Al-Sn-Cu Based Immiscible Alloys under Intense Shearing