Modular Transformations, Order-Chaos Transitions and Pseudo-Random Number Generation

Science.gov (United States)

Bonelli, Antonio; Ruffo, Stefano

Successive pairs of pseudo-random numbers generated by standard linear congruential transformations display ordered patterns of parallel lines. We study the "ordered" and "chaotic" distribution of such pairs by solving the eigenvalue problem for two-dimensional modular transformations over integers. We conjecture that the optimal uniformity for pair distribution is obtained when the slope of linear modular eigenspaces takes the value n opt =maxint (p/√ {p-1}), where p is a prime number. We then propose a new generator of pairs of independent pseudo-random numbers, which realizes an optimal uniform distribution (in the "statistical" sense) of points on the unit square (0, 1] × (0, 1]. The method can be easily generalized to the generation of k-tuples of random numbers (with k>2).

The contribution of second-order processes to (3He, n) calculations

International Nuclear Information System (INIS)

Brissaud, I.

1978-01-01

The reactions 90 Zr, 116 Cd( 3 He, n) have been analysed by adding two second-order processes to the usual one-step DWBA calculations: sequential stripping or inelastic transition followed by double stripping. These second-order contributions increase the cross sections, especially for 90 Zr, and improve the shape of the angular distribution for 116 Cd. It shows that such second-order processes cannot be omitted in the analysis of two-particle stripping reactions. (author)

Constructing set-valued fundamental diagrams from jamiton solutions in second order traffic models

KAUST Repository

Seibold, Benjamin

2013-09-01

Fundamental diagrams of vehicular traiic ow are generally multivalued in the congested ow regime. We show that such set-valued fundamental diagrams can be constructed systematically from simple second order macroscopic traiic models, such as the classical Payne-Whitham model or the inhomogeneous Aw-Rascle-Zhang model. These second order models possess nonlinear traveling wave solutions, called jamitons, and the multi-valued parts in the fundamental diagram correspond precisely to jamiton-dominated solutions. This study shows that transitions from function-valued to set-valued parts in a fundamental diagram arise naturally in well-known second order models. As a particular consequence, these models intrinsically reproduce traiic phases. © American Institute of Mathematical Sciences.

Constructing set-valued fundamental diagrams from jamiton solutions in second order traffic models

KAUST Repository

Seibold, Benjamin; Flynn, Morris R.; Kasimov, Aslan R.; Rosales, Rodolfo Rubé n

2013-01-01

Fundamental diagrams of vehicular traiic ow are generally multivalued in the congested ow regime. We show that such set-valued fundamental diagrams can be constructed systematically from simple second order macroscopic traiic models, such as the classical Payne-Whitham model or the inhomogeneous Aw-Rascle-Zhang model. These second order models possess nonlinear traveling wave solutions, called jamitons, and the multi-valued parts in the fundamental diagram correspond precisely to jamiton-dominated solutions. This study shows that transitions from function-valued to set-valued parts in a fundamental diagram arise naturally in well-known second order models. As a particular consequence, these models intrinsically reproduce traiic phases. © American Institute of Mathematical Sciences.

Do pseudo-absence selection strategies influence species distribution models and their predictions? An information-theoretic approach based on simulated data

Directory of Open Access Journals (Sweden)

Guisan Antoine

2009-04-01

Full Text Available Abstract Background Multiple logistic regression is precluded from many practical applications in ecology that aim to predict the geographic distributions of species because it requires absence data, which are rarely available or are unreliable. In order to use multiple logistic regression, many studies have simulated "pseudo-absences" through a number of strategies, but it is unknown how the choice of strategy influences models and their geographic predictions of species. In this paper we evaluate the effect of several prevailing pseudo-absence strategies on the predictions of the geographic distribution of a virtual species whose "true" distribution and relationship to three environmental predictors was predefined. We evaluated the effect of using a real absences b pseudo-absences selected randomly from the background and c two-step approaches: pseudo-absences selected from low suitability areas predicted by either Ecological Niche Factor Analysis: (ENFA or BIOCLIM. We compared how the choice of pseudo-absence strategy affected model fit, predictive power, and information-theoretic model selection results. Results Models built with true absences had the best predictive power, best discriminatory power, and the "true" model (the one that contained the correct predictors was supported by the data according to AIC, as expected. Models based on random pseudo-absences had among the lowest fit, but yielded the second highest AUC value (0.97, and the "true" model was also supported by the data. Models based on two-step approaches had intermediate fit, the lowest predictive power, and the "true" model was not supported by the data. Conclusion If ecologists wish to build parsimonious GLM models that will allow them to make robust predictions, a reasonable approach is to use a large number of randomly selected pseudo-absences, and perform model selection based on an information theoretic approach. However, the resulting models can be expected to have

Second-order moments of Schell-model beams with various correlation functions in atmospheric turbulence.

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Zheng, Guo; Wang, Jue; Wang, Lin; Zhou, Muchun; Xin, Yu; Song, Minmin

2017-11-15

The general formulae for second-order moments of Schell-model beams with various correlation functions in atmospheric turbulence are derived and validated by the Bessel-Gaussian Schell-model beams and cosine-Gaussian-correlated Schell-model beams. Our finding shows that the second-order moments of partially coherent Schell-model beams are related to the second-order partial derivatives of source spectral degree of coherence at the origin. The formulae we provide are much more convenient to analyze and research propagation problems in turbulence.

Access is mainly a second-order process: SDT models whether phenomenally (first-order) conscious states are accessed by reflectively (second-order) conscious processes.

Science.gov (United States)

Snodgrass, Michael; Kalaida, Natasha; Winer, E Samuel

2009-06-01

Access can either be first-order or second-order. First order access concerns whether contents achieve representation in phenomenal consciousness at all; second-order access concerns whether phenomenally conscious contents are selected for metacognitive, higher order processing by reflective consciousness. When the optional and flexible nature of second-order access is kept in mind, there remain strong reasons to believe that exclusion failure can indeed isolate phenomenally conscious stimuli that are not so accessed. Irvine's [Irvine, E. (2009). Signal detection theory, the exclusion failure paradigm and weak consciousness-Evidence for the access/phenomenal distinction? Consciousness and Cognition.] partial access argument fails because exclusion failure is indeed due to lack of second-order access, not insufficient phenomenally conscious information. Further, the enable account conforms with both qualitative differences and subjective report, and is simpler than the endow account. Finally, although first-order access may be a distinct and important process, second-order access arguably reflects the core meaning of access generally.

Abnormal Waves Modelled as Second-order Conditional Waves

DEFF Research Database (Denmark)

Jensen, Jørgen Juncher

2005-01-01

The paper presents results for the expected second order short-crested wave conditional of a given wave crest at a specific point in time and space. The analysis is based on the second order Sharma and Dean shallow water wave theory. Numerical results showing the importance of the spectral densit...

Lagrangian generic second order traffic flow models for node

Directory of Open Access Journals (Sweden)

Asma Khelifi

2018-02-01

Full Text Available This study sheds light on higher order macroscopic traffic flow modeling on road networks, thanks to the generic second order models (GSOM family which embeds a myriad of traffic models. It has been demonstrated that such higher order models are easily solved in Lagrangian coordinates which are compatible with both microscopic and macroscopic descriptions. The generalized GSOM model is reformulated in the Lagrangian coordinate system to develop a more efficient numerical method. The difficulty in applying this approach on networks basically resides in dealing with node dynamics. Traffic flow characteristics at node are different from that on homogeneous links. Different geometry features can lead to different critical research issues. For instance, discontinuity in traffic stream can be an important issue for traffic signal operations, while capacity drop may be crucial for lane-merges. The current paper aims to establish and analyze a new adapted node model for macroscopic traffic flow models by applying upstream and downstream boundary conditions on the Lagrangian coordinates in order to perform simulations on networks of roads, and accompanying numerical method. The internal node dynamics between upstream and downstream links are taken into account of the node model. Therefore, a numerical example is provided to underscore the efficiency of this approach. Simulations show that the discretized node model yields accurate results. Additional kinematic waves and contact discontinuities are induced by the variation of the driver attribute.

Noise-and delay-induced phase transitions of the dimer–monomer surface reaction model

International Nuclear Information System (INIS)

Zeng Chunhua; Wang Hua

2012-01-01

Highlights: ► We study the dimer–monomer surface reaction model. ► We show that noise induces first-order irreversible phase transition (IPT). ► Combination of noise and time-delayed feedback induce first- and second-order IPT. ► First- and second-order IPT is viewed as noise-and delay-induced phase transitions. - Abstract: The effects of noise and time-delayed feedback in the dimer–monomer (DM) surface reaction model are investigated. Applying small delay approximation, we construct a stochastic delayed differential equation and its Fokker–Planck equation to describe the state evolution of the DM reaction model. We show that the noise can only induce first-order irreversible phase transition (IPT) characteristic of the DM model, however the combination of the noise and time-delayed feedback can simultaneously induce first- and second-order IPT characteristics of the DM model. Therefore, it is shown that the well-known first- and second-order IPT characteristics of the DM model may be viewed as noise-and delay-induced phase transitions.

Reactor dynamics experiment of nuclear ship Mutsu using pseudo random signal (II). The second experiment

International Nuclear Information System (INIS)

Hayashi, Koji; Shimazaki, Junya; Nabeshima, Kunihiko; Ochiai, Masaaki; Shinohara, Yoshikuni; Inoue, Kimihiko.

1995-01-01

In order to investigate dynamics of the reactor plant of the nuclear ship Mutsu, the second reactor noise experiment using pseudo random binary sequences (PRBS) was performed on August 30, 1991 in the third experimental navigation. The experiments using both reactivity and load disturbances were performed at 50% of reactor power and under a quiet sea condition. Each PRBS was applied by manual operation of the control rod or the main steam valve. Various signals of the plant responses and of the acceleration of ship motion were measured. Furthermore, natural reactor noise signals were measured after each PRBS experiment in order to evaluate the effects of the PRBS disturbances. This paper summarizes the planning of the experiment, the instruction for the experiment and logs, the data recording conditions, recorded signal wave forms and the results of power spectral analysis. (author)

Generalised linear models for correlated pseudo-observations, with applications to multi-state models

DEFF Research Database (Denmark)

Andersen, Per Kragh; Klein, John P.; Rosthøj, Susanne

2003-01-01

Generalised estimating equation; Generalised linear model; Jackknife pseudo-value; Logistic regression; Markov Model; Multi-state model......Generalised estimating equation; Generalised linear model; Jackknife pseudo-value; Logistic regression; Markov Model; Multi-state model...

New second order Mumford-Shah model based on Γ-convergence approximation for image processing

Science.gov (United States)

Duan, Jinming; Lu, Wenqi; Pan, Zhenkuan; Bai, Li

2016-05-01

In this paper, a second order variational model named the Mumford-Shah total generalized variation (MSTGV) is proposed for simultaneously image denoising and segmentation, which combines the original Γ-convergence approximated Mumford-Shah model with the second order total generalized variation (TGV). For image denoising, the proposed MSTGV can eliminate both the staircase artefact associated with the first order total variation and the edge blurring effect associated with the quadratic H1 regularization or the second order bounded Hessian regularization. For image segmentation, the MSTGV can obtain clear and continuous boundaries of objects in the image. To improve computational efficiency, the implementation of the MSTGV does not directly solve its high order nonlinear partial differential equations and instead exploits the efficient split Bregman algorithm. The algorithm benefits from the fast Fourier transform, analytical generalized soft thresholding equation, and Gauss-Seidel iteration. Extensive experiments are conducted to demonstrate the effectiveness and efficiency of the proposed model.

Geometric model of pseudo-distance measurement in satellite location systems

Science.gov (United States)

Panchuk, K. L.; Lyashkov, A. A.; Lyubchinov, E. V.

2018-04-01

The existing mathematical model of pseudo-distance measurement in satellite location systems does not provide a precise solution of the problem, but rather an approximate one. The existence of such inaccuracy, as well as bias in measurement of distance from satellite to receiver, results in inaccuracy level of several meters. Thereupon, relevance of refinement of the current mathematical model becomes obvious. The solution of the system of quadratic equations used in the current mathematical model is based on linearization. The objective of the paper is refinement of current mathematical model and derivation of analytical solution of the system of equations on its basis. In order to attain the objective, geometric analysis is performed; geometric interpretation of the equations is given. As a result, an equivalent system of equations, which allows analytical solution, is derived. An example of analytical solution implementation is presented. Application of analytical solution algorithm to the problem of pseudo-distance measurement in satellite location systems allows to improve the accuracy such measurements.

Semiorders, Intervals Orders and Pseudo Orders Preference Structures in Multiple Criteria Decision Aid Methods

Directory of Open Access Journals (Sweden)

Fernández Barberis, Gabriela

2013-06-01

Full Text Available During the last decades, an important number of Multicriteria Decision Aid Methods (MCDA has been proposed to help the decision maker to select the best compromise alternative. Meanwhile, the PROMETHEE (Preference Ranking Organization Method for Enrichment Evaluations family of outranking method and their applications has attracted much attention from academics and practitioners. In this paper, an extension of these methods is presented, consisting of analyze its functioning under New Preference Structures (NPS. The preference structures taken into account are, namely: semiorders, intervals orders and pseudo orders. These structures outstandingly improve the modelization as they give more flexibility, amplitude and certainty at the preferences formulation, since they tend to abandon the Complete Transitive Comparability Axiom of Preferences in order to substitute it by the Partial Comparability Axiom of Preferences. It must be remarked the introduction of Incomparability relations to the analysis and the consideration of preference structures that accept the Indifference intransitivity. The NPS incorporation is carried out in three phases that the PROMETHEE Methodology takes in: preference structure enrichment, dominance relation enrichment and outranking relation exploitation for decision aid, in order to finally arrive at solving the alternatives ranking problem through the PROMETHEE I or the PROMETHEE II utilization, according to whether a partial ranking or a complete one, is respectively required under the NPS

RhoA/ROCK Signaling Pathway Mediates Shuanghuanglian Injection-Induced Pseudo-allergic Reactions.

Science.gov (United States)

Han, Jiayin; Zhao, Yong; Zhang, Yushi; Li, Chunying; Yi, Yan; Pan, Chen; Tian, Jingzhuo; Yang, Yifei; Cui, Hongyu; Wang, Lianmei; Liu, Suyan; Liu, Jing; Deng, Nuo; Liang, Aihua

2018-01-01

Background: Shuanghuanglian injection (SHLI) is a famous Chinese medicine used as an intravenous preparation for the treatment of acute respiratory tract infections. In the recent years, the immediate hypersensitivity reactions induced by SHLI have attracted broad attention. However, the mechanism involved in these reactions has not yet been elucidated. The present study aims to explore the characteristics of the immediate hypersensitivity reactions induced by SHLI and deciphers the role of the RhoA/ROCK signaling pathway in these reactions. Methods: SHLI-immunized mice or naive mice were intravenously injected (i.v.) with SHLI (600 mg/kg) once, and vascular leakage in the ears was evaluated. Passive cutaneous anaphylaxis test was conducted using sera collected from SHLI-immunized mice. Naive mice were administered (i.v.) with a single dose of 150, 300, or 600 mg/kg of SHLI, and vascular leakage, histamine release, and histopathological alterations in the ears, lungs, and intestines were tested. In vitro , human umbilical vein endothelial cell (HUVEC) monolayer was incubated with SHLI (0.05, 0.1, or 0.15 mg/mL), and the changes in endothelial permeability and cytoskeleton were observed. Western blot analysis was performed and ROCK inhibitor was employed to investigate the contribution of the RhoA/ROCK signaling pathway in SHLI-induced hypersensitivity reactions, both in HUVECs and in mice. Results: Our results indicate that SHLI was able to cause immediate dose-dependent vascular leakage, edema, and exudates in the ears, lungs, and intestines, and histamine release in mice. These were pseudo-allergic reactions, as SHLI-specific IgE was not elicited during sensitization. In addition, SHLI induced reorganization of actin cytoskeleton and disrupted the endothelial barrier. The administration of SHLI directly activated the RhoA/ROCK signaling pathway both in HUVECs and in the ears, lungs, and intestines of mice. Fasudil hydrochloride, a ROCK inhibitor, ameliorated the

Pseudo-Haptic Feedback in Teleoperation.

Science.gov (United States)

Neupert, Carsten; Matich, Sebastian; Scherping, Nick; Kupnik, Mario; Werthschutzky, Roland; Hatzfeld, Christian

2016-01-01

In this paper, we develop possible realizations of pseudo-haptic feedback in teleoperation systems based on existing works for pseudo-haptic feedback in virtual reality and the intended applications. We derive four potential factors affecting the performance of haptic feedback (calculation operator, maximum displacement, offset force, and scaling factor), which are analyzed in three compliance identification experiments. First, we analyze the principle usability of pseudo-haptic feedback by comparing information transfer measures for teleoperation and direct interaction. Pseudo-haptic interaction yields well above-chance performance, while direct interaction performs almost perfectly. In order to optimize pseudo-haptic feedback, in the second study we perform a full-factorial experimental design with 36 subjects performing 6,480 trials with 36 different treatments. Information transfer ranges from 0.68 bit to 1.72 bit in a task with a theoretical maximum of 2.6 bit, with a predominant effect of the calculation operator and a minor effect of the maximum displacement. In a third study, short- and long-term learning effects are analyzed. Learning effects regarding the performance of pseudo-haptic feedback cannot be observed for single-day experiments. Tests over 10 days show a maximum increase in information transfer of 0.8 bit. The results show the feasibility of pseudo-haptic feedback for teleoperation and can be used as design basis for task-specific systems.

Calculating Second-Order Effects in MOSFET's

Science.gov (United States)

Benumof, Reuben; Zoutendyk, John A.; Coss, James R.

1990-01-01

Collection of mathematical models includes second-order effects in n-channel, enhancement-mode, metal-oxide-semiconductor field-effect transistors (MOSFET's). When dimensions of circuit elements relatively large, effects neglected safely. However, as very-large-scale integration of microelectronic circuits leads to MOSFET's shorter or narrower than 2 micrometer, effects become significant in design and operation. Such computer programs as widely-used "Simulation Program With Integrated Circuit Emphasis, Version 2" (SPICE 2) include many of these effects. In second-order models of n-channel, enhancement-mode MOSFET, first-order gate-depletion region diminished by triangular-cross-section deletions on end and augmented by circular-wedge-cross-section bulges on sides.

Second-order splitting schemes for a class of reactive systems

International Nuclear Information System (INIS)

Ren Zhuyin; Pope, Stephen B.

2008-01-01

We consider the numerical time integration of a class of reaction-transport systems that are described by a set of ordinary differential equations for primary variables. In the governing equations, the terms involved may require the knowledge of secondary variables, which are functions of the primary variables. Specifically, we consider the case where, given the primary variables, the evaluation of the secondary variables is computationally expensive. To solve this class of reaction-transport equations, we develop and demonstrate several computationally efficient splitting schemes, wherein the portions of the governing equations containing chemical reaction terms are separated from those parts containing the transport terms. A computationally efficient solution to the transport sub-step is achieved through the use of linearization or predictor-corrector methods. The splitting schemes are applied to the reactive flow in a continuously stirred tank reactor (CSTR) with the Davis-Skodjie reaction model, to the CO+H 2 oxidation in a CSTR with detailed chemical kinetics, and to a reaction-diffusion system with an extension of the Oregonator model of the Belousov-Zhabotinsky reaction. As demonstrated in the test problems, the proposed splitting schemes, which yield efficient solutions to the transport sub-step, achieve second-order accuracy in time

Third-order optical intensity correlation measurements of pseudo-thermal light

International Nuclear Information System (INIS)

Chen Xi-Hao; Wu Wei; Meng Shao-Ying; Li Ming-Fei

2014-01-01

Third-order Hanbrury Brown—Twiss and double-slit interference experiments with a pseudo-thermal light are performed by recording intensities in single, double and triple optical paths, respectively. The experimental results verifies the theoretical prediction that the indispensable condition for achieving a interference pattern or ghost image in Nth-order intensity correlation measurements is the synchronous detection of the same light field by each reference detector, no matter the intensities recorded in one, or two, or N optical paths. It is shown that, when the reference detectors are scanned in the opposite directions, the visibility and resolution of the third-order spatial correlation function of thermal light is much better than that scanned in the same direction, but it is no use for obtaining the Nth-order interference pattern or ghost image in the thermal Nth-order interference or ghost imaging. (general)

A comprehensive investigation of the pseudo-skin factor for partially completed vertical wells

International Nuclear Information System (INIS)

Farokhi, Vahid; Gerami, Shahab

2012-01-01

To prohibit gas and/or water coning, it is very common for wells to be completed over only a portion of their productive zone. Such a procedure causes an additional pressure drop, termed the pseudo-skin factor, which reduces the well productivity. In order to ascertain whether or not a partially penetrated well requires stimulation, one has to quantitatively determine the different components of the total skin. Hence, an accurate evaluation of the pseudo-skin factor as one of the main components of the total skin is critical. Many authors have employed different mathematics to find expressions for estimating the pseudo-skin factor, however, since a comprehensive investigation of the available models has not as yet been performed, the diversity of these expressions could be very confusing. This paper first aims to propose an analytical model which accurately estimates the pseudo-skin factor in a partially penetrated well. In model development, the impacts of anisotropy and the arbitrariness of the open interval location are all taken into account, and the model is validated against a numerical simulator (ECLIPSE). Its second aim is to take the results of the numerical simulator as the comparison basis, and make a comprehensive investigation of the available models to check their accuracy for estimating the pseudo-skin factor. The results of the investigation show that, in comparison to other methods, this proposed model, Streltsova's method and that of Yeh and Reynolds, estimate the pseudo-skin factor favourably close to that obtained by the simulator. (paper)

Evaluation of the kinetic oxidation of aqueous volatile organic compounds by permanganate.

Science.gov (United States)

Mahmoodlu, Mojtaba G; Hassanizadeh, S Majid; Hartog, Niels

2014-07-01

The use of permanganate solutions for in-situ chemical oxidation (ISCO) is a well-established groundwater remediation technology, particularly for targeting chlorinated ethenes. The kinetics of oxidation reactions is an important ISCO remediation design aspect that affects the efficiency and oxidant persistence. The overall rate of the ISCO reaction between oxidant and contaminant is typically described using a second-order kinetic model while the second-order rate constant is determined experimentally by means of a pseudo first order approach. However, earlier studies of chlorinated hydrocarbons have yielded a wide range of values for the second-order rate constants. Also, there is limited insight in the kinetics of permanganate reactions with fuel-derived groundwater contaminants such as toluene and ethanol. In this study, batch experiments were carried out to investigate and compare the oxidation kinetics of aqueous trichloroethylene (TCE), ethanol, and toluene in an aqueous potassium permanganate solution. The overall second-order rate constants were determined directly by fitting a second-order model to the data, instead of typically using the pseudo-first-order approach. The second-order reaction rate constants (M(-1) s(-1)) for TCE, toluene, and ethanol were 8.0×10(-1), 2.5×10(-4), and 6.5×10(-4), respectively. Results showed that the inappropriate use of the pseudo-first-order approach in several previous studies produced biased estimates of the second-order rate constants. In our study, this error was expressed as a function of the extent (P/N) in which the reactant concentrations deviated from the stoichiometric ratio of each oxidation reaction. The error associated with the inappropriate use of the pseudo-first-order approach is negatively correlated with the P/N ratio and reached up to 25% of the estimated second-order rate constant in some previous studies of TCE oxidation. Based on our results, a similar relation is valid for the other volatile

Simultaneous measurements of reactive scalar and velocity in a planar liquid jet with a second-order chemical reaction

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Tomoaki; Sakai, Yasuhiko; Nagata, Kouji; Terashima, Osamu [Nagoya University, Department of Mechanical Science and Engineering, Nagoya (Japan); Kubo, Takashi [Meijo University, Faculty of Science and Technology, Nagoya (Japan)

2012-11-15

This paper presents a new experimental approach for simultaneous measurements of velocity and concentration in a turbulent liquid flow with a chemical reaction. For the simultaneous measurements, we developed a combined probe consisting of an I-type hot-film probe and an optical fiber probe based on the light absorption spectrometric method. In a turbulent planar liquid jet with a second-order chemical reaction (A+B{yields}R), streamwise velocity and concentrations of all reactive species are measured by the combined probe. The turbulent mass fluxes of the reactive species are estimated from the simultaneous measurements. The results show that the influence of the chemical reaction on the turbulent mass flux of the reactant species near the jet exit is different from its influence in other regions, and the turbulent mass flux of the product species has a negative value near the jet exit and a positive value in other regions. (orig.)

Post processing of optically recognized text via second order hidden Markov model

Science.gov (United States)

Poudel, Srijana

In this thesis, we describe a postprocessing system on Optical Character Recognition(OCR) generated text. Second Order Hidden Markov Model (HMM) approach is used to detect and correct the OCR related errors. The reason for choosing the 2nd order HMM is to keep track of the bigrams so that the model can represent the system more accurately. Based on experiments with training data of 159,733 characters and testing of 5,688 characters, the model was able to correct 43.38 % of the errors with a precision of 75.34 %. However, the precision value indicates that the model introduced some new errors, decreasing the correction percentage to 26.4%.

Modeling Studies of Inhomogeneity Effects during Laser Flash Photolysis Experiments: A Reaction-Diffusion Approach.

Science.gov (United States)

Dóka, Éva; Lente, Gábor

2017-04-13

This work presents a rigorous mathematical study of the effect of unavoidable inhomogeneities in laser flash photolysis experiments. There are two different kinds of inhomegenities: the first arises from diffusion, whereas the second one has geometric origins (the shapes of the excitation and detection light beams). Both of these are taken into account in our reported model, which gives rise to a set of reaction-diffusion type partial differential equations. These equations are solved by a specially developed finite volume method. As an example, the aqueous reaction between the sulfate ion radical and iodide ion is used, for which sufficiently detailed experimental data are available from an earlier publication. The results showed that diffusion itself is in general too slow to influence the kinetic curves on the usual time scales of laser flash photolysis experiments. However, the use of the absorbances measured (e.g., to calculate the molar absorption coefficients of transient species) requires very detailed mathematical consideration and full knowledge of the geometrical shapes of the excitation laser beam and the separate detection light beam. It is also noted that the usual pseudo-first-order approach to evaluating the kinetic traces can be used successfully even if the usual large excess condition is not rigorously met in the reaction cell locally.

SECOND ORDER LEAST SQUARE ESTIMATION ON ARCH(1 MODEL WITH BOX-COX TRANSFORMED DEPENDENT VARIABLE

Directory of Open Access Journals (Sweden)

Herni Utami

2014-03-01

Full Text Available Box-Cox transformation is often used to reduce heterogeneity and to achieve a symmetric distribution of response variable. In this paper, we estimate the parameters of Box-Cox transformed ARCH(1 model using second-order leastsquare method and then we study the consistency and asymptotic normality for second-order least square (SLS estimators. The SLS estimation was introduced byWang (2003, 2004 to estimate the parameters of nonlinear regression models with independent and identically distributed errors

The lattice Boltzmann model for the second-order Benjamin–Ono equations

International Nuclear Information System (INIS)

Lai, Huilin; Ma, Changfeng

2010-01-01

In this paper, in order to extend the lattice Boltzmann method to deal with more complicated nonlinear equations, we propose a 1D lattice Boltzmann scheme with an amending function for the second-order (1 + 1)-dimensional Benjamin–Ono equation. With the Taylor expansion and the Chapman–Enskog expansion, the governing evolution equation is recovered correctly from the continuous Boltzmann equation. The equilibrium distribution function and the amending function are obtained. Numerical simulations are carried out for the 'good' Boussinesq equation and the 'bad' one to validate the proposed model. It is found that the numerical results agree well with the analytical solutions. The present model can be used to solve more kinds of nonlinear partial differential equations

Five-Year-Olds’ Systematic Errors in Second-Order False Belief Tasks Are Due to First-Order Theory of Mind Strategy Selection: A Computational Modeling Study

Science.gov (United States)

Arslan, Burcu; Taatgen, Niels A.; Verbrugge, Rineke

2017-01-01

The focus of studies on second-order false belief reasoning generally was on investigating the roles of executive functions and language with correlational studies. Different from those studies, we focus on the question how 5-year-olds select and revise reasoning strategies in second-order false belief tasks by constructing two computational cognitive models of this process: an instance-based learning model and a reinforcement learning model. Unlike the reinforcement learning model, the instance-based learning model predicted that children who fail second-order false belief tasks would give answers based on first-order theory of mind (ToM) reasoning as opposed to zero-order reasoning. This prediction was confirmed with an empirical study that we conducted with 72 5- to 6-year-old children. The results showed that 17% of the answers were correct and 83% of the answers were wrong. In line with our prediction, 65% of the wrong answers were based on a first-order ToM strategy, while only 29% of them were based on a zero-order strategy (the remaining 6% of subjects did not provide any answer). Based on our instance-based learning model, we propose that when children get feedback “Wrong,” they explicitly revise their strategy to a higher level instead of implicitly selecting one of the available ToM strategies. Moreover, we predict that children’s failures are due to lack of experience and that with exposure to second-order false belief reasoning, children can revise their wrong first-order reasoning strategy to a correct second-order reasoning strategy. PMID:28293206

Five-Year-Olds' Systematic Errors in Second-Order False Belief Tasks Are Due to First-Order Theory of Mind Strategy Selection: A Computational Modeling Study.

Science.gov (United States)

Arslan, Burcu; Taatgen, Niels A; Verbrugge, Rineke

2017-01-01

The focus of studies on second-order false belief reasoning generally was on investigating the roles of executive functions and language with correlational studies. Different from those studies, we focus on the question how 5-year-olds select and revise reasoning strategies in second-order false belief tasks by constructing two computational cognitive models of this process: an instance-based learning model and a reinforcement learning model. Unlike the reinforcement learning model, the instance-based learning model predicted that children who fail second-order false belief tasks would give answers based on first-order theory of mind (ToM) reasoning as opposed to zero-order reasoning. This prediction was confirmed with an empirical study that we conducted with 72 5- to 6-year-old children. The results showed that 17% of the answers were correct and 83% of the answers were wrong. In line with our prediction, 65% of the wrong answers were based on a first-order ToM strategy, while only 29% of them were based on a zero-order strategy (the remaining 6% of subjects did not provide any answer). Based on our instance-based learning model, we propose that when children get feedback "Wrong," they explicitly revise their strategy to a higher level instead of implicitly selecting one of the available ToM strategies. Moreover, we predict that children's failures are due to lack of experience and that with exposure to second-order false belief reasoning, children can revise their wrong first-order reasoning strategy to a correct second-order reasoning strategy.

On pseudo-values for regression analysis in competing risks models

DEFF Research Database (Denmark)

Graw, F; Gerds, Thomas Alexander; Schumacher, M

2009-01-01

For regression on state and transition probabilities in multi-state models Andersen et al. (Biometrika 90:15-27, 2003) propose a technique based on jackknife pseudo-values. In this article we analyze the pseudo-values suggested for competing risks models and prove some conjectures regarding their...

Kinetics and reaction mechanism for aminolysis of benzyl 4-pyridyl carbonate in H2O: Effect of modification of nucleofuge from 2-pyridyl oxide to 4-pyridyl oxide on reactivity and reaction mechanism

International Nuclear Information System (INIS)

Kang, Ji Sun; Um, Ikhwan

2012-01-01

Pseudo-first-order rate constants k amine have been measured spectrophotometrically for the reactions of benzyl 4-pyridyl carbonate 6 with a series of alicyclic secondary amines in H 2 O at 25.0.deg.C. The plots of k amine vs. [amine] curve upward, indicating that the reactions proceed through a stepwise mechanism with two intermediates, a zwitterionic tetrahedral intermediate T ± and its deprotonated form T - . This contrasts to the report that the corresponding reactions of benzyl 2-pyridyl carbonate 5 proceed through a forced concerted pathway. The k amine values for the reactions of 6 have been dissected into the second-order rate constant Kk 2 and the third order rate constant Kk 3 . The Brφnsted-type plots are linear with β nuc = 0.94 and 1.18 for Kk 2 and Kk 3 , respectively. The Kk 2 for the reaction of 6 is smaller than the second-order rate constant k N for the corresponding reaction of 5, although 4-pyridyl oxide in 6 is less basic and a better nucleofuge than 2-pyridyl oxide in 5

Second-Order Risk Constraints in Decision Analysis

Directory of Open Access Journals (Sweden)

Love Ekenberg

2014-01-01

Full Text Available Recently, representations and methods aimed at analysing decision problems where probabilities and values (utilities are associated with distributions over them (second-order representations have been suggested. In this paper we present an approach to how imprecise information can be modelled by means of second-order distributions and how a risk evaluation process can be elaborated by integrating procedures for numerically imprecise probabilities and utilities. We discuss some shortcomings of the use of the principle of maximising the expected utility and of utility theory in general, and offer remedies by the introduction of supplementary decision rules based on a concept of risk constraints taking advantage of second-order distributions.

On nonlinear reduced order modeling

International Nuclear Information System (INIS)

Abdel-Khalik, Hany S.

2011-01-01

When applied to a model that receives n input parameters and predicts m output responses, a reduced order model estimates the variations in the m outputs of the original model resulting from variations in its n inputs. While direct execution of the forward model could provide these variations, reduced order modeling plays an indispensable role for most real-world complex models. This follows because the solutions of complex models are expensive in terms of required computational overhead, thus rendering their repeated execution computationally infeasible. To overcome this problem, reduced order modeling determines a relationship (often referred to as a surrogate model) between the input and output variations that is much cheaper to evaluate than the original model. While it is desirable to seek highly accurate surrogates, the computational overhead becomes quickly intractable especially for high dimensional model, n ≫ 10. In this manuscript, we demonstrate a novel reduced order modeling method for building a surrogate model that employs only 'local first-order' derivatives and a new tensor-free expansion to efficiently identify all the important features of the original model to reach a predetermined level of accuracy. This is achieved via a hybrid approach in which local first-order derivatives (i.e., gradient) of a pseudo response (a pseudo response represents a random linear combination of original model’s responses) are randomly sampled utilizing a tensor-free expansion around some reference point, with the resulting gradient information aggregated in a subspace (denoted by the active subspace) of dimension much less than the dimension of the input parameters space. The active subspace is then sampled employing the state-of-the-art techniques for global sampling methods. The proposed method hybridizes the use of global sampling methods for uncertainty quantification and local variational methods for sensitivity analysis. In a similar manner to

Two component WIMP-FImP dark matter model with singlet fermion, scalar and pseudo scalar

Energy Technology Data Exchange (ETDEWEB)

Dutta Banik, Amit; Pandey, Madhurima; Majumdar, Debasish [Saha Institute of Nuclear Physics, HBNI, Astroparticle Physics and Cosmology Division, Kolkata (India); Biswas, Anirban [Harish Chandra Research Institute, Allahabad (India)

2017-10-15

We explore a two component dark matter model with a fermion and a scalar. In this scenario the Standard Model (SM) is extended by a fermion, a scalar and an additional pseudo scalar. The fermionic component is assumed to have a global U(1){sub DM} and interacts with the pseudo scalar via Yukawa interaction while a Z{sub 2} symmetry is imposed on the other component - the scalar. These ensure the stability of both dark matter components. Although the Lagrangian of the present model is CP conserving, the CP symmetry breaks spontaneously when the pseudo scalar acquires a vacuum expectation value (VEV). The scalar component of the dark matter in the present model also develops a VEV on spontaneous breaking of the Z{sub 2} symmetry. Thus the various interactions of the dark sector and the SM sector occur through the mixing of the SM like Higgs boson, the pseudo scalar Higgs like boson and the singlet scalar boson. We show that the observed gamma ray excess from the Galactic Centre as well as the 3.55 keV X-ray line from Perseus, Andromeda etc. can be simultaneously explained in the present two component dark matter model and the dark matter self interaction is found to be an order of magnitude smaller than the upper limit estimated from the observational results. (orig.)

Pointwise second-order necessary optimality conditions and second-order sensitivity relations in optimal control

Science.gov (United States)

Frankowska, Hélène; Hoehener, Daniel

2017-06-01

This paper is devoted to pointwise second-order necessary optimality conditions for the Mayer problem arising in optimal control theory. We first show that with every optimal trajectory it is possible to associate a solution p (ṡ) of the adjoint system (as in the Pontryagin maximum principle) and a matrix solution W (ṡ) of an adjoint matrix differential equation that satisfy a second-order transversality condition and a second-order maximality condition. These conditions seem to be a natural second-order extension of the maximum principle. We then prove a Jacobson like necessary optimality condition for general control systems and measurable optimal controls that may be only ;partially singular; and may take values on the boundary of control constraints. Finally we investigate the second-order sensitivity relations along optimal trajectories involving both p (ṡ) and W (ṡ).

Second-order sliding mode controller with model reference adaptation for automatic train operation

Science.gov (United States)

Ganesan, M.; Ezhilarasi, D.; Benni, Jijo

2017-11-01

In this paper, a new approach to model reference based adaptive second-order sliding mode control together with adaptive state feedback is presented to control the longitudinal dynamic motion of a high speed train for automatic train operation with the objective of minimal jerk travel by the passengers. The nonlinear dynamic model for the longitudinal motion of the train comprises of a locomotive and coach subsystems is constructed using multiple point-mass model by considering the forces acting on the vehicle. An adaptation scheme using Lyapunov criterion is derived to tune the controller gains by considering a linear, stable reference model that ensures the stability of the system in closed loop. The effectiveness of the controller tracking performance is tested under uncertain passenger load, coupler-draft gear parameters, propulsion resistance coefficients variations and environmental disturbances due to side wind and wet rail conditions. The results demonstrate improved tracking performance of the proposed control scheme with a least jerk under maximum parameter uncertainties when compared to constant gain second-order sliding mode control.

A unified model for transfer alignment at random misalignment angles based on second-order EKF

International Nuclear Information System (INIS)

Cui, Xiao; Qin, Yongyuan; Yan, Gongmin; Liu, Zhenbo; Mei, Chunbo

2017-01-01

In the transfer alignment process of inertial navigation systems (INSs), the conventional linear error model based on the small misalignment angle assumption cannot be applied to large misalignment situations. Furthermore, the nonlinear model based on the large misalignment angle suffers from redundant computation with nonlinear filters. This paper presents a unified model for transfer alignment suitable for arbitrary misalignment angles. The alignment problem is transformed into an estimation of the relative attitude between the master INS (MINS) and the slave INS (SINS), by decomposing the attitude matrix of the latter. Based on the Rodriguez parameters, a unified alignment model in the inertial frame with the linear state-space equation and a second order nonlinear measurement equation are established, without making any assumptions about the misalignment angles. Furthermore, we employ the Taylor series expansions on the second-order nonlinear measurement equation to implement the second-order extended Kalman filter (EKF2). Monte-Carlo simulations demonstrate that the initial alignment can be fulfilled within 10 s, with higher accuracy and much smaller computational cost compared with the traditional unscented Kalman filter (UKF) at large misalignment angles. (paper)

A unified model for transfer alignment at random misalignment angles based on second-order EKF

Science.gov (United States)

Cui, Xiao; Mei, Chunbo; Qin, Yongyuan; Yan, Gongmin; Liu, Zhenbo

2017-04-01

In the transfer alignment process of inertial navigation systems (INSs), the conventional linear error model based on the small misalignment angle assumption cannot be applied to large misalignment situations. Furthermore, the nonlinear model based on the large misalignment angle suffers from redundant computation with nonlinear filters. This paper presents a unified model for transfer alignment suitable for arbitrary misalignment angles. The alignment problem is transformed into an estimation of the relative attitude between the master INS (MINS) and the slave INS (SINS), by decomposing the attitude matrix of the latter. Based on the Rodriguez parameters, a unified alignment model in the inertial frame with the linear state-space equation and a second order nonlinear measurement equation are established, without making any assumptions about the misalignment angles. Furthermore, we employ the Taylor series expansions on the second-order nonlinear measurement equation to implement the second-order extended Kalman filter (EKF2). Monte-Carlo simulations demonstrate that the initial alignment can be fulfilled within 10 s, with higher accuracy and much smaller computational cost compared with the traditional unscented Kalman filter (UKF) at large misalignment angles.

Brain MR image segmentation using NAMS in pseudo-color.

Science.gov (United States)

Li, Hua; Chen, Chuanbo; Fang, Shaohong; Zhao, Shengrong

2017-12-01

Image segmentation plays a crucial role in various biomedical applications. In general, the segmentation of brain Magnetic Resonance (MR) images is mainly used to represent the image with several homogeneous regions instead of pixels for surgical analyzing and planning. This paper proposes a new approach for segmenting MR brain images by using pseudo-color based segmentation with Non-symmetry and Anti-packing Model with Squares (NAMS). First of all, the NAMS model is presented. The model can represent the image with sub-patterns to keep the image content and largely reduce the data redundancy. Second, the key idea is proposed that convert the original gray-scale brain MR image into a pseudo-colored image and then segment the pseudo-colored image with NAMS model. The pseudo-colored image can enhance the color contrast in different tissues in brain MR images, which can improve the precision of segmentation as well as directly visual perceptional distinction. Experimental results indicate that compared with other brain MR image segmentation methods, the proposed NAMS based pseudo-color segmentation method performs more excellent in not only segmenting precisely but also saving storage.

Second Order Ideal-Ward Continuity

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Bipan Hazarika

2014-01-01

Full Text Available The main aim of the paper is to introduce a concept of second order ideal-ward continuity in the sense that a function f is second order ideal-ward continuous if I-limn→∞Δ2f(xn=0 whenever I-limn→∞Δ2xn=0 and a concept of second order ideal-ward compactness in the sense that a subset E of R is second order ideal-ward compact if any sequence x=(xn of points in E has a subsequence z=(zk=(xnk of the sequence x such that I-limk→∞Δ2zk=0 where Δ2zk=zk+2-2zk+1+zk. We investigate the impact of changing the definition of convergence of sequences on the structure of ideal-ward continuity in the sense of second order ideal-ward continuity and compactness of sets in the sense of second order ideal-ward compactness and prove related theorems.

Effects of large rate coefficients for ion-polar neutral reactions on chemical models of dense interstellar clouds

International Nuclear Information System (INIS)

Herbst, E.; Leung, C.M.; Rensselaer Polytechnic Institute, Troy, NY)

1986-01-01

Pseudo-time-dependent models of the gas phase chemistry of dense interstellar clouds have been run with large rate coefficients for reactions between ions and polar neutral species, as advocated by Adams, Smith, and Clary. The higher rate coefficients normally lead to a reduction in both the peak and steady state abundances of polar neutrals, which can be as large as an order of magnitude but is more often smaller. Other differences between the results of these models and previous results are also discussed. 38 references

TSOAK-M1: an examination of its model and methods

International Nuclear Information System (INIS)

Edgell, D.H.

1983-05-01

Fusion facilities will contain a sizable inventory of tritium fuel that will be vulnerable to release. Once released, molecular tritium begins converting into tritiated water which is 10000 times more hazardous and tends to adsorb onto surfaces. The rate of conversion and adsorption/desorption must be accurately known to estimate cleanup times and radiation hazards realistically. Argonne National Laboratory developed a computer code, TSOAK-M1, to determine the conversion/ adsorption/desorption parameters and to model cleanups. The Canadian Fusion Fuels Technology Project examined the program for reliability and potential applications. TSOAK-M1 assumes a pseudo second order radiolytic conversion where a first order surface reaction seems more appropriate. This difference in order should be investigated to accurately determine the reaction law. TSOAK-M1 determines the model parameters from experimental data using an optimization routine. However the data used is judged insufficient. More data is needed where the conversion of molecular tritium to tritiated water has a significant effect due to adsorption/desorption. SOAKER, an improved version of the TSOAK-M1 model, which combines first and second order reactions has been implemented in Wang BASIC. Once the reaction law and the parameters have been accurately determined the program could be a useful tool in the study and design of decontamination systems

Binocular Combination of Second-Order Stimuli

Science.gov (United States)

Zhou, Jiawei; Liu, Rong; Zhou, Yifeng; Hess, Robert F.

2014-01-01

Phase information is a fundamental aspect of visual stimuli. However, the nature of the binocular combination of stimuli defined by modulations in contrast, so-called second-order stimuli, is presently not clear. To address this issue, we measured binocular combination for first- (luminance modulated) and second-order (contrast modulated) stimuli using a binocular phase combination paradigm in seven normal adults. We found that the binocular perceived phase of second-order gratings depends on the interocular signal ratio as has been previously shown for their first order counterparts; the interocular signal ratios when the two eyes were balanced was close to 1 in both first- and second-order phase combinations. However, second-order combination is more linear than previously found for first-order combination. Furthermore, binocular combination of second-order stimuli was similar regardless of whether the carriers in the two eyes were correlated, anti-correlated, or uncorrelated. This suggests that, in normal adults, the binocular phase combination of second-order stimuli occurs after the monocular extracting of the second-order modulations. The sensory balance associated with this second-order combination can be obtained from binocular phase combination measurements. PMID:24404180

A second-order class-D audio amplifier

OpenAIRE

Cox, Stephen M.; Tan, M.T.; Yu, J.

2011-01-01

Class-D audio amplifiers are particularly efficient, and this efficiency has led to their ubiquity in a wide range of modern electronic appliances. Their output takes the form of a high-frequency square wave whose duty cycle (ratio of on-time to off-time) is modulated at low frequency according to the audio signal. A mathematical model is developed here for a second-order class-D amplifier design (i.e., containing one second-order integrator) with negative feedback. We derive exact expression...

Sorption of malachite green from aqueous solution by potato peel: Kinetics and equilibrium modeling using non-linear analysis method

Directory of Open Access Journals (Sweden)

El-Khamsa Guechi

2016-09-01

Full Text Available Potato peel (PP was used as a biosorbent to remove malachite green (MG from aqueous solution under various operating conditions. The effect of the experimental parameters such as initial dye concentration, biosorbent dose, initial pH, stirring speed, temperature, ionic strength and biosorbent particle size was investigated through a number of batch sorption experiments. The sorption kinetic uptake for MG by PP at various initial dye concentrations was analyzed by non-linear method using pseudo-first, pseudo-second and pseudo-nth order models. It was found that the pseudo-nth order kinetic model was the best applicable model to describe the sorption kinetic data and the order n of sorption reaction was calculated in the range from 0.71 to 2.71. Three sorption isotherms namely the Langmuir, Freundlich and Redlich–Peterson isotherms in their non-linear forms were applied to the biosorption equilibrium data. Both the Langmuir and Redlich–Peterson models were found to fit the sorption isotherm data well, but the Redlich–Peterson model was better. Thermodynamic parameters show that the sorption process of MG is endothermic and more effective process at high temperatures. The results revealed that PP is very effective for the biosorption of MG from aqueous solutions.

Nonlinear Growth Models as Measurement Models: A Second-Order Growth Curve Model for Measuring Potential.

Science.gov (United States)

McNeish, Daniel; Dumas, Denis

2017-01-01

Recent methodological work has highlighted the promise of nonlinear growth models for addressing substantive questions in the behavioral sciences. In this article, we outline a second-order nonlinear growth model in order to measure a critical notion in development and education: potential. Here, potential is conceptualized as having three components-ability, capacity, and availability-where ability is the amount of skill a student is estimated to have at a given timepoint, capacity is the maximum amount of ability a student is predicted to be able to develop asymptotically, and availability is the difference between capacity and ability at any particular timepoint. We argue that single timepoint measures are typically insufficient for discerning information about potential, and we therefore describe a general framework that incorporates a growth model into the measurement model to capture these three components. Then, we provide an illustrative example using the public-use Early Childhood Longitudinal Study-Kindergarten data set using a Michaelis-Menten growth function (reparameterized from its common application in biochemistry) to demonstrate our proposed model as applied to measuring potential within an educational context. The advantage of this approach compared to currently utilized methods is discussed as are future directions and limitations.

Wetting transitions: First order or second order

International Nuclear Information System (INIS)

Teletzke, G.F.; Scriven, L.E.; Davis, H.T.

1982-01-01

A generalization of Sullivan's recently proposed theory of the equilibrium contact angle, the angle at which a fluid interface meets a solid surface, is investigated. The generalized theory admits either a first-order or second-order transition from a nonzero contact angle to perfect wetting as a critical point is approached, in contrast to Sullivan's original theory, which predicts only a second-order transition. The predictions of this computationally convenient theory are in qualitative agreement with a more rigorous theory to be presented in a future publication

Pseudo-capacitor device for aqueous electrolytes

Science.gov (United States)

Prakash, Jai; Thackeray, Michael M.; Dees, Dennis W.; Vissers, Donald R.; Myles, Kevin M.

1998-01-01

A pseudo-capacitor having a high energy storage capacity develops a double layer capacitance as well as a Faradaic or battery-like redox reaction, also referred to as pseudo-capacitance. The Faradaic reaction gives rise to a capacitance much greater than that of the typical ruthenate oxide ultracapacitor which develops only charge separation-based double layer capacitance. The capacitor employs a lead and/or bismuth/ruthenate and/or iridium system having the formula A.sub.2 ›B.sub.2-x Pb.sub.x !O.sub.7-y, where A=Pb, Bi, and B=Ru, Ir, and Ocapacitor. The amount of expensive ruthenate and iridium can be substantially reduced in the pseudo-capacitor by increasing the lead content while improving energy storage capacity.

Studies of nuclear second moments for pre-equilibrium nuclear reaction theories

International Nuclear Information System (INIS)

Sato, K.; Yoshida, S.

1987-01-01

The nuclear second moments, important inputs to pre-equilibrium reaction theories, are evaluated by assuming a simple model. The positive definite nature of the second moments is examined, and the nuclear level densities are calculated using positive definite second moments. (orig.)

Second order numerical method of two-fluid model of air-water flow

International Nuclear Information System (INIS)

Tiselj, I.; Petelin, S.

1995-01-01

Model considered in this paper is six-equation two-fluid model used in computer code RELAP5. Air-water equations were taken in a code named PDE to avoid additional problems caused by condensation or vaporization. Terms with space derivatives were added in virtual mass term in momentum equations to ensure the hyperbolicity of the equations. Numerical method in PDE code is based on approximate Riemann solvers. Equations are solved on non-staggered grid with explicit time advancement and with upwind discretization of the convective terms in characteristic form of the equations. Flux limiters are used to find suitable combinations of the first (upwind) and the second order (Lax-Wendroff) discretization s which ensure second order accuracy on smooth solutions and damp oscillations around the discontinuities. Because of the small time steps required and because of its non-dissipative nature the scheme is suitable for the prediction of the fast transients: pressure waves, shock and rarefaction waves, water hammer or critical flow. Some preliminary results are presented for a shock tube problem and for Water Faucet problem - problems usually used as benchmarks for two-fluid computer codes. (author)

Kinetics of soybean oil epoxidation with peracetic acid formed in situ in the presence of an ion exchange resin: Pseudo-homogeneous model

Directory of Open Access Journals (Sweden)

Janković Milovan

2017-01-01

Full Text Available A kinetic model was proposed for the epoxidation of vegetable oils with peracetic acid formed in situ from acetic acid and hydrogen peroxide in the presence of an acidic ion exchange resin as a catalyst. The model is pseudo-homogeneous with respect to the catalyst. Besides the main reactions of peracetic acid and epoxy ring formation, the model takes into account the side reaction of epoxy ring opening with acetic acid. The partitioning of acetic acid and peracetic acid between the aqueous and organic phases and the change in the phases’ volumes during the process were considered. The temperature dependency of the apparent reaction rate coefficients is described by a reparameterized Arrhenius equation. The constants in the proposed model were estimated by fitting the experimental data obtained for the epoxidations of soybean oil conducted under defined reaction conditions. The highest epoxy yield of 87.73% was obtained at 338 K when the mole ratio of oil unsaturation:acetic acid:hydrogen peroxide was 1:0.5:1.35 and when the amount of the catalyst Amberlite IR-120H was 4.04 wt.% of oil. Compared to the other reported pseudo-homogeneous models, the model proposed in this study better correlates the change of double bond and epoxy group contents during the epoxidation process. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45022

A model for pseudo-Dirac neutrinos: leptogenesis and ultra-high energy neutrinos

Energy Technology Data Exchange (ETDEWEB)

Ahn, Y.H. [Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS),Daejeon, 34051 (Korea, Republic of); Kang, Sin Kyu [Insitute for Convergence Fundamental Study, School of Liberal Arts, Seoul-Tech.,Seoul, 01811 (Korea, Republic of); Kim, C.S. [Dept. of Physics and IPAP, Yonsei University,Seoul, 120-749 (Korea, Republic of)

2016-10-18

We propose a model where sterile neutrinos are introduced to make light neutrinos to be pseudo-Dirac particles. It is shown how tiny mass splitting necessary for realizing pseudo-Dirac neutrinos can be achieved. Within the model, we show how leptogenesis can be successfully generated. Motivated by the recent observation of very high energy neutrino events at IceCube, we study a possibility to observe the effects of the pseudo-Dirac property of neutrinos by performing astronomical-scale baseline experiments to uncover the oscillation effects of very tiny mass splitting. We also discuss future prospect to observe the effects of the pseudo-Dirac property of neutrinos at high energy neutrino experiments.

Second-order nonlinearity induced transparency.

Science.gov (United States)

Zhou, Y H; Zhang, S S; Shen, H Z; Yi, X X

2017-04-01

In analogy to electromagnetically induced transparency, optomechanically induced transparency was proposed recently in [Science330, 1520 (2010)SCIEAS0036-807510.1126/science.1195596]. In this Letter, we demonstrate another form of induced transparency enabled by second-order nonlinearity. A practical application of the second-order nonlinearity induced transparency is to measure the second-order nonlinear coefficient. Our scheme might find applications in quantum optics and quantum information processing.

Microscopic cascading of second-order molecular nonlinearity: New design principles for enhancing third-order nonlinearity.

Science.gov (United States)

Baev, Alexander; Autschbach, Jochen; Boyd, Robert W; Prasad, Paras N

2010-04-12

Herein, we develop a phenomenological model for microscopic cascading and substantiate it with ab initio calculations. It is shown that the concept of local microscopic cascading of a second-order nonlinearity can lead to a third-order nonlinearity, without introducing any new loss mechanisms that could limit the usefulness of our approach. This approach provides a new molecular design protocol, in which the current great successes achieved in producing molecules with extremely large second-order nonlinearity can be used in a supra molecular organization in a preferred orientation to generate very large third-order response magnitudes. The results of density functional calculations for a well-known second-order molecule, (para)nitroaniline, show that a head-to-tail dimer configuration exhibits enhanced third-order nonlinearity, in agreement with the phenomenological model which suggests that such an arrangement will produce cascading due to local field effects.

MODELLING OF KINETICS OF FLUORINE ADSORPTION ONTO MODIFIED DIATOMITE

Directory of Open Access Journals (Sweden)

VEACESLAV ZELENTSOV

2017-03-01

Full Text Available The paper presents kinetics modelling of adsorption of fluorine onto modified diatomite, its fundamental characteristics and mathematical derivations. Three models of defluoridation kinetics were used to fit the experimental results on adsorption fluorine onto diatomite: the pseudo-first order model Lagergren, the pseudo-second order model G. McKay and H.S. Ho and intraparticle diffusion model of W.J. Weber and J.C. Morris. Kinetics studies revealed that the adsorption of fluorine followed second-order rate model, complimented by intraparticle diffusion kinetics. The adsorption mechanism of fluorine involved three stages – external surface adsorption, intraparticle diffusion and the stage of equilibrium.

An implicit second order numerical method for two-fluid models

International Nuclear Information System (INIS)

Toumi, I.

1995-01-01

We present an implicit upwind numerical method for a six equation two-fluid model based on a linearized Riemann solver. The construction of this approximate Riemann solver uses an extension of Roe's scheme. Extension to second order accurate method is achieved using a piecewise linear approximation of the solution and a slope limiter method. For advancing in time, a linearized implicit integrating step is used. In practice this new numerical method has proved to be stable and capable of generating accurate non-oscillating solutions for two-phase flow calculations. The scheme was applied both to shock tube problems and to standard tests for two-fluid codes. (author)

Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media

KAUST Repository

Pestana, Reynam C

2012-04-24

In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ε- δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media. © 2012 Sinopec Geophysical Research Institute.

Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media

KAUST Repository

Pestana, Reynam C; Ursin, Bjø rn; Stoffa, Paul L

2012-01-01

In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ε- δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media. © 2012 Sinopec Geophysical Research Institute.

PENGARUH SORPSI AIR DAN SUHU TRANSISI GELAS TERHADAP LAJU PENCOKLATAN NON-ENZIMATIS PADA PANGAN MODEL [The Effect of Water Sorption and Glass Transition Temperature on Non-Enzymatic Browning Reaction of Food Models

Directory of Open Access Journals (Sweden)

Dede R Adawiyah1

2005-12-01

Full Text Available This research was aimer/ to study the extend of non enzymatic browning reaction in food models containing the mixture of tapioca starch, casein, sucrose and oh at different moisture contents (2.55%, 5.26%, 7.54%, 15.20%. 15.93% and 23.99% and storage temperatures (30, 55 and 700C. The non-enzymatic browning reaction was detected from brown color intensity measured by spechtrophotometer and colorimetric methods. The non-enzymatic browning reaction or food model follow pseudo-zero order reaction, suggesting that browning reaction occurred at moisture content above monolayer zone. T-Tg (T storage - Tg prediction and reaction rate constant (k plots showed that browning reaction occurred at temperature around glass transition and increased significantly at 150 above Tg of casein. Tapioca starch in the food model was under glassy condition. The mobility of substrate increased and diffused at amorphous matrix.

Second Order Sliding Mode Controller Design for Pneumatic Artificial Muscle

Directory of Open Access Journals (Sweden)

Ammar Al-Jodah

2018-01-01

Full Text Available In this paper, first and second order sliding mode controllers are designed for a single link robotic arm actuated by two Pneumatic Artificial Muscles (PAMs. A new mathematical model for the arm has been developed based on the model of large scale pneumatic muscle actuator model. Uncertainty in parameters has been presented and tested for the two controllers. The simulation results of the second-order sliding mode controller proves to have a low tracking error and chattering effect as compared to the first order one. The verification has been done by using MATLAB and Simulink software.

Algebra of pseudo-differential C*-operators

International Nuclear Information System (INIS)

Mohammad, N.

1987-11-01

In this paper the algebra of pseudo-differential operators is studied in the framework of C * -algebras. It is proved that every pseudo-differential operator of order m admits an adjoint operator, in this case, which is again a pseudo-differential operator. Consequently, the space of all pseudo-differential operators on a compact manifold is an involutive algebra. 10 refs

Discrete Second-Order Sliding Mode Adaptive Controller Based on Characteristic Model for Servo Systems

Directory of Open Access Journals (Sweden)

Zhihong Wang

2015-01-01

Full Text Available Considering the varying inertia and load torque in high speed and high accuracy servo systems, a novel discrete second-order sliding mode adaptive controller (DSSMAC based on characteristic model is proposed, and a command observer is also designed. Firstly, the discrete characteristic model of servo systems is established. Secondly, the recursive least square algorithm is adopted to identify time-varying parameters in characteristic model, and the observer is applied to predict the command value of next sample time. Furthermore, the stability of the closed-loop system and the convergence of the observer are analyzed. The experimental results show that the proposed method not only can adapt to varying inertia and load torque, but also has good disturbance rejection ability and robustness to uncertainties.

Second Order Sliding Mode Controller Design for Pneumatic Artificial Muscle

OpenAIRE

Ammar Al-Jodah; Laith Khames

2018-01-01

In this paper, first and second order sliding mode controllers are designed for a single link robotic arm actuated by two Pneumatic Artificial Muscles (PAMs). A new mathematical model for the arm has been developed based on the model of large scale pneumatic muscle actuator model. Uncertainty in parameters has been presented and tested for the two controllers. The simulation results of the second-order sliding mode controller proves to have a low tracking error and chattering effect as compar...

Second-Order Science of Interdisciplinary Research

DEFF Research Database (Denmark)

Alrøe, Hugo Fjelsted; Noe, Egon

2014-01-01

require and challenge interdisciplinarity. Problem: The conventional methods of interdisciplinary research fall short in the case of wicked problems because they remain first-order science. Our aim is to present workable methods and research designs for doing second-order science in domains where...... there are many different scientific knowledges on any complex problem. Method: We synthesize and elaborate a framework for second-order science in interdisciplinary research based on a number of earlier publications, experiences from large interdisciplinary research projects, and a perspectivist theory...... of science. Results: The second-order polyocular framework for interdisciplinary research is characterized by five principles. Second-order science of interdisciplinary research must: 1. draw on the observations of first-order perspectives, 2. address a shared dynamical object, 3. establish a shared problem...

Roof planes detection via a second-order variational model

Science.gov (United States)

Benciolini, Battista; Ruggiero, Valeria; Vitti, Alfonso; Zanetti, Massimo

2018-04-01

The paper describes a unified automatic procedure for the detection of roof planes in gridded height data. The procedure exploits the Blake-Zisserman (BZ) model for segmentation in both 2D and 1D, and aims to detect, to model and to label roof planes. The BZ model relies on the minimization of a functional that depends on first- and second-order derivatives, free discontinuities and free gradient discontinuities. During the minimization, the relative strength of each competitor is controlled by a set of weight parameters. By finding the minimum of the approximated BZ functional, one obtains: (1) an approximation of the data that is smoothed solely within regions of homogeneous gradient, and (2) an explicit detection of the discontinuities and gradient discontinuities of the approximation. Firstly, input data is segmented using the 2D BZ. The maps of data and gradient discontinuities are used to isolate building candidates and planar patches (i.e. regions with homogeneous gradient) that correspond to roof planes. Connected regions that can not be considered as buildings are filtered according to both patch dimension and distribution of the directions of the normals to the boundary. The 1D BZ model is applied to the curvilinear coordinates of boundary points of building candidates in order to reduce the effect of data granularity when the normals are evaluated. In particular, corners are preserved and can be detected by means of gradient discontinuity. Lastly, a total least squares model is applied to estimate the parameters of the plane that best fits the points of each planar patch (orthogonal regression with planar model). Refinement of planar patches is performed by assigning those points that are close to the boundaries to the planar patch for which a given proximity measure assumes the smallest value. The proximity measure is defined to account for the variance of a fitting plane and a weighted distance of a point from the plane. The effectiveness of the

Relaxation approximations to second-order traffic flow models by high-resolution schemes

International Nuclear Information System (INIS)

Nikolos, I.K.; Delis, A.I.; Papageorgiou, M.

2015-01-01

A relaxation-type approximation of second-order non-equilibrium traffic models, written in conservation or balance law form, is considered. Using the relaxation approximation, the nonlinear equations are transformed to a semi-linear diagonilizable problem with linear characteristic variables and stiff source terms with the attractive feature that neither Riemann solvers nor characteristic decompositions are in need. In particular, it is only necessary to provide the flux and source term functions and an estimate of the characteristic speeds. To discretize the resulting relaxation system, high-resolution reconstructions in space are considered. Emphasis is given on a fifth-order WENO scheme and its performance. The computations reported demonstrate the simplicity and versatility of relaxation schemes as numerical solvers

A porous flow model of flank eruptions on Mt. Etna: second-order perturbation theory

Directory of Open Access Journals (Sweden)

N. Cenni

1997-06-01

Full Text Available A porous flow model for magma migration from a deep source within a volcanic edifice is developed. The model is based on the assumption that an isotropic and homogeneous system of fractures allows magma migration from one localized feeding dyke up to the surface of the volcano. The maximum level that magma can reach within the volcano (i.e., the «free surface» of magma, where fluid pressure equals the atmospheric pressure is reproduced through a second-order perturbation approach to the non-linear equations governing the migration of incompressible fluids through a porous medium. The perturbation parameter is found to depend on the ratio of the volumic discharge rate at the source (m3/s divided by the product of the hydraulic conductivity of the medium (m1/s times the square of the source depth. The second-order corrections for the free surface of Mt. Etna are found to be small but not negligible; from the comparison between first-order and second-order free surfaces it appears that the former is higher near the summit, slightly lower at intermediate altitudes and slightly higher far away from the axis of the volcano. Flank eruptions in the southern sector are found to be located in regions where the topography is actually lower than the theoretical free surface of magma. In this sector, modulations in the eruption site density correlate well with even minor differences between free surface and topography. In the northern and western sectors similar good fits are found, while the NE rift and the eastern sector seem to require mechanisms or structures respectively favouring and inhibiting magma migration.

Electronic properties of large metal clusters in Jellium and pseudo-jellium models

International Nuclear Information System (INIS)

Catara, F.; Van Giai, N.; Chomaz, P.

1994-08-01

The energy-density functional approach and jellium-like models are used to examine two important electronic properties of metal (Li, Na, K) clusters: their shell and supershell structures, and the behaviour of plasmon energies with increasing cluster sizes. A comparative study is made between predictions of the usual jellium model and those of the pseudo-jellium model where pseudo-Hamiltonians are used. (authors) 10 figs., 5 tabs., 16 refs

Heavy ion and hadron reactions in emulsion

International Nuclear Information System (INIS)

Otterlund, I.

1979-04-01

Recent results from heavy ion and hadron reactions in emulsion are reviewed. General properties of hadron-reaction multiplicities and their correlation to the production of recoiling protons are given. Properties of pseudo-rapidity distributions of shower-particles especially the particle production in the central region of pseudo-rapidity will be discussed. Non-peripheral heavy ion reactions are compared to recent participant-spectator model calculations. Very energetic cosmic ray events will be examined in the light of recent results from hadron-nucleus reactions. (author)

Accuracy Enhanced Stability and Structure Preserving Model Reduction Technique for Dynamical Systems with Second Order Structure

DEFF Research Database (Denmark)

Tahavori, Maryamsadat; Shaker, Hamid Reza

A method for model reduction of dynamical systems with the second order structure is proposed in this paper. The proposed technique preserves the second order structure of the system, and also preserves the stability of the original systems. The method uses the controllability and observability...... gramians within the time interval to build the appropriate Petrov-Galerkin projection for dynamical systems within the time interval of interest. The bound on approximation error is also derived. The numerical results are compared with the counterparts from other techniques. The results confirm...

A Second Look at Second-Order Belief Attribution in Autism.

Science.gov (United States)

Tager-Flusberg, Helen; Sullivan, Kate

1994-01-01

Twelve students with autism and 12 with mental retardation, who had passed a first-order test of false belief, were given a second-order reasoning task. No intergroup performance differences were seen. Findings suggest that the difficulty for both groups with the second-order task lies in information processing demands rather than conceptual…

Second-order gauge-invariant perturbations during inflation

International Nuclear Information System (INIS)

Finelli, F.; Marozzi, G.; Vacca, G. P.; Venturi, G.

2006-01-01

The evolution of gauge invariant second-order scalar perturbations in a general single field inflationary scenario are presented. Different second-order gauge-invariant expressions for the curvature are considered. We evaluate perturbatively one of these second order curvature fluctuations and a second-order gauge-invariant scalar field fluctuation during the slow-roll stage of a massive chaotic inflationary scenario, taking into account the deviation from a pure de Sitter evolution and considering only the contribution of super-Hubble perturbations in mode-mode coupling. The spectra resulting from their contribution to the second order quantum correlation function are nearly scale-invariant, with additional logarithmic corrections with respect to the first order spectrum. For all scales of interest the amplitude of these spectra depends on the total number of e-folds. We find, on comparing first and second order perturbation results, an upper limit to the total number of e-folds beyond which the two orders are comparable

Synchronization from Second Order Network Connectivity Statistics

Science.gov (United States)

Zhao, Liqiong; Beverlin, Bryce; Netoff, Theoden; Nykamp, Duane Q.

2011-01-01

We investigate how network structure can influence the tendency for a neuronal network to synchronize, or its synchronizability, independent of the dynamical model for each neuron. The synchrony analysis takes advantage of the framework of second order networks, which defines four second order connectivity statistics based on the relative frequency of two-connection network motifs. The analysis identifies two of these statistics, convergent connections, and chain connections, as highly influencing the synchrony. Simulations verify that synchrony decreases with the frequency of convergent connections and increases with the frequency of chain connections. These trends persist with simulations of multiple models for the neuron dynamics and for different types of networks. Surprisingly, divergent connections, which determine the fraction of shared inputs, do not strongly influence the synchrony. The critical role of chains, rather than divergent connections, in influencing synchrony can be explained by their increasing the effective coupling strength. The decrease of synchrony with convergent connections is primarily due to the resulting heterogeneity in firing rates. PMID:21779239

Pseudo potentials and model potentials in atomic collisions

International Nuclear Information System (INIS)

Reyes, O.; Jouin, H.; Fuentealba, P.

1988-01-01

In this work, it is discussed the main differences between the use of pseudo-potentials and model potentials in collision problems . It is shown the potential energy curves for distinct systems obtained with both kinds of potentials. (A.C.A.S.) [pt

Assessment of First- and Second-Order Wave-Excitation Load Models for Cylindrical Substructures: Preprint

Energy Technology Data Exchange (ETDEWEB)

Pereyra, Brandon; Wendt, Fabian; Robertson, Amy; Jonkman, Jason

2017-03-09

The hydrodynamic loads on an offshore wind turbine's support structure present unique engineering challenges for offshore wind. Two typical approaches used for modeling these hydrodynamic loads are potential flow (PF) and strip theory (ST), the latter via Morison's equation. This study examines the first- and second-order wave-excitation surge forces on a fixed cylinder in regular waves computed by the PF and ST approaches to (1) verify their numerical implementations in HydroDyn and (2) understand when the ST approach breaks down. The numerical implementation of PF and ST in HydroDyn, a hydrodynamic time-domain solver implemented as a module in the FAST wind turbine engineering tool, was verified by showing the consistency in the first- and second-order force output between the two methods across a range of wave frequencies. ST is known to be invalid at high frequencies, and this study investigates where the ST solution diverges from the PF solution. Regular waves across a range of frequencies were run in HydroDyn for a monopile substructure. As expected, the solutions for the first-order (linear) wave-excitation loads resulting from these regular waves are similar for PF and ST when the diameter of the cylinder is small compared to the length of the waves (generally when the diameter-to-wavelength ratio is less than 0.2). The same finding applies to the solutions for second-order wave-excitation loads, but for much smaller diameter-to-wavelength ratios (based on wavelengths of first-order waves).

Measurement Invariance of Second-Order Factor Model of the Multifactor Leadership Questionnaire (MLQ) across K-12 Principal Gender

Science.gov (United States)

Xu, Lihua; Wubbena, Zane; Stewart, Trae

2016-01-01

Purpose: The purpose of this paper is to investigate the factor structure and the measurement invariance of the Multifactor Leadership Questionnaire (MLQ) across gender of K-12 school principals (n=6,317) in the USA. Design/methodology/approach: Nine first-order factor models and four second-order factor models were tested using confirmatory…

Sea of Majorana fermions from pseudo-scalar superconducting order in three dimensional Dirac materials.

Science.gov (United States)

Salehi, Morteza; Jafari, S A

2017-08-15

We suggest that spin-singlet pseudo-scalar s-wave superconducting pairing creates a two dimensional sea of Majorana fermions on the surface of three dimensional Dirac superconductors (3DDS). This pseudo-scalar superconducting order parameter Δ 5 , in competition with scalar Dirac mass m, leads to a topological phase transition due to band inversion. We find that a perfect Andreev-Klein reflection is guaranteed by presence of anomalous Andreev reflection along with the conventional one. This effect manifests itself in a resonant peak of the differential conductance. Furthermore, Josephson current of the Δ 5 |m|Δ 5 junction in the presence of anomalous Andreev reflection is fractional with 4π period. Our finding suggests another search area for condensed matter realization of Majorana fermions which are beyond the vortex-core of p-wave superconductors. The required Δ 5 pairing can be extrinsically induced by a conventional s-wave superconductor into a three dimensional Dirac material (3DDM).

Source of second order chromaticity in RHIC

International Nuclear Information System (INIS)

Luo, Y.; Gu, X.; Fischer, W.; Trbojevic, D.

2011-01-01

In this note we will answer the following questions: (1) what is the source of second order chromaticities in RHIC? (2) what is the dependence of second order chromaticity on the on-momentum β-beat? (3) what is the dependence of second order chromaticity on β* at IP6 and IP8? To answer these questions, we use the perturbation theory to numerically calculate the contributions of each quadrupole and sextupole to the first, second, and third order chromaticities.

Second-Rate Coverage of Second-Order Elections: Czech and Slovak Elections to the EP in the Media

Directory of Open Access Journals (Sweden)

Jan Kovář

2010-12-01

Full Text Available Elections to the European Parliament (EP are considered second-order national elections (SOE. The SOE model suggests that there is a qualitative difference between different types of elections depending on the perception of what is at stake. Compared to first order elections, in second order elections there is less at stake because they do not determine the composition of government. Given that voters behave differently in second-order elections, the question arises: do the media also consider second-order elections less interesting and therefore devote to them less coverage? The media play a crucial role in informing citizens about such events as elections; they function as intermediaries between the electorate and the political arena. However, little is known about how EU issues are covered in the media, particularly in the new EU member states. Conducting a content analysis and applying the second-order election model, this paper analyses TV news coverage of the 2004 and 2009 European elections in the Czech Republic and Slovakia in a comparative fashion. The findings are discussed in the light of existing research literature on the EU’s legitimacy as well as its alleged democratic and communication deficit, not least because the EU relies on the media in strengthening (albeit indirectly its legitimacy by increasing citizen awareness of its activities.

Glycerol acetals, kinetic study of the reaction between glycerol and formaldehyde

International Nuclear Information System (INIS)

Agirre, I.; Garcia, I.; Requies, J.; Barrio, V.L.; Gueemez, M.B.; Cambra, J.F.; Arias, P.L.

2011-01-01

The acetalization reaction between glycerol and formaldehyde using Amberlyst 47 acidic ion exchange resin was studied. These acetals can be obtained from renewable sources (bioalcohols and bioalcohol derived aldehydes) and seem to be good candidates for different applications such as oxygenated diesel additives. A preliminary kinetic study was performed in a batch stirred tank reactor studying the influence of different process parameters like temperature, feed composition and the stirring speed. A pseudo homogenous kinetic model able to explain the reaction mechanism was adjusted. Thus, the corresponding order of reaction was determined. Amberlyst 47 acidic ion exchange resin showed a fairly good behavior allowing 100% of selectivity towards acetals formation. However, the studied acetalization reaction showed high thermodynamic limitations achieving glycerol conversions around 50% using a stoichiometric feed ratio at 353 K. The product is a mixture of two isomers (1,3-Dioxan-5-ol and 1,3-dioxolane-4-methanol) and the conversion of 1,3-dioxolane-4-methanol into 1,3-Dioxan-5-ol was also observed. -- Highlights: → The reaction between glycerol and acetaldehyde shows thermodynamic limitations. → Amberlyst 47 ion exchange resins show 100% of selectivity. → A pseudo-homogeneous kinetic model is able to predict the reaction progress. → Isomerization reactions were observed from dioxalanes to dioxanes.

An Analysis of Second-Order Autoshaping

Science.gov (United States)

Ward-Robinson, Jasper

2004-01-01

Three mechanisms can explain second-order conditioning: (1) The second-order conditioned stimulus (CS2) could activate a representation of the first-order conditioned stimulus (CS1), thereby provoking the conditioned response (CR); The CS2 could enter into an excitatory association with either (2) the representation governing the CR, or (3) with a…

First and second order vortex dynamics

International Nuclear Information System (INIS)

Kim, Yoonbai; Lee, Kimyeong

2002-01-01

The low energy dynamics of vortices in self-dual Abelian Higgs theory in (2+1)-dimensional spacetime is of second order in vortex velocity and characterized by the moduli space metric. When the Chern-Simons term with a small coefficient is added to the theory, we show that a term linear in vortex velocity appears and can be consistently added to the second order expression. We provide an additional check of the first and second order terms by studying the angular momentum in field theory

Adsorption kinetic parameters of Fe3+ and Ni2+ ions by gyrolite

Directory of Open Access Journals (Sweden)

Kestutis Baltakys

2015-03-01

Full Text Available In this work the adsorption kinetic parameters for Fe3+ and Ni2+ ions by gyrolite are presented. Additionally, the adsoption mechanism was described by using pseudo first order and pseudo second order  equations. It was determined that the adsorption capacity of gyrolite and intrusion of heavy metals ions in its structure depends on reaction time and the pH value of adsorptive. It was observed that the incorporation of Fe3+ ions occurs more intensive than Ni2+ ions. It was found that in the acidic solution the intrusion of Fe3+ ions into gyrolite structure proceeds by two types of chemical reaction mechanisms: substitution and addition. Meanwhile, nickel ions were participated only in substitution reaction: gyrolite-Ca0 + Mex+ ↔ gyrolite-Me0 + Ca2+. It was observed that the pseudo second order model fit well for iron and nickel ions adsorption mechanism. It was estimated that the adsorption reactions are not reversible process and the crystal structure of gyrolite is stable. Moreover, synthetic adsorbent and the products of sorption were characterized by XRD, STA and FT-IR methods.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5735

Team Resilience as a Second-Order Emergent State: A Theoretical Model and Research Directions

Directory of Open Access Journals (Sweden)

Clint Bowers

2017-08-01

Full Text Available Resilience has been recognized as an important phenomenon for understanding how individuals overcome difficult situations. However, it is not only individuals who face difficulties; it is not uncommon for teams to experience adversity. When they do, they must be able to overcome these challenges without performance decrements.This manuscript represents a theoretical model that might be helpful in conceptualizing this important construct. Specifically, it describes team resilience as a second-order emergent state. We also include research propositions that follow from the model.

Generalized Second-Order Parametric Optimality Conditions in Semiinfinite Discrete Minmax Fractional Programming and Second-Order Univexity

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Ram Verma

2016-02-01

Full Text Available This paper deals with mainly establishing numerous sets of generalized second order paramertic sufficient optimality conditions for a semiinfinite discrete minmax fractional programming problem, while the results on semiinfinite discrete minmax fractional programming problem achieved based on some partitioning schemes under various types of generalized second order univexity assumptions. 

Modeling of second order space charge driven coherent sum and difference instabilities

Directory of Open Access Journals (Sweden)

Yao-Shuo Yuan

2017-10-01

Full Text Available Second order coherent oscillation modes in intense particle beams play an important role for beam stability in linear or circular accelerators. In addition to the well-known second order even envelope modes and their instability, coupled even envelope modes and odd (skew modes have recently been shown in [Phys. Plasmas 23, 090705 (2016PHPAEN1070-664X10.1063/1.4963851] to lead to parametric instabilities in periodic focusing lattices with sufficiently different tunes. While this work was partly using the usual envelope equations, partly also particle-in-cell (PIC simulation, we revisit these modes here and show that the complete set of second order even and odd mode phenomena can be obtained in a unifying approach by using a single set of linearized rms moment equations based on “Chernin’s equations.” This has the advantage that accurate information on growth rates can be obtained and gathered in a “tune diagram.” In periodic focusing we retrieve the parametric sum instabilities of coupled even and of odd modes. The stop bands obtained from these equations are compared with results from PIC simulations for waterbag beams and found to show very good agreement. The “tilting instability” obtained in constant focusing confirms the equivalence of this method with the linearized Vlasov-Poisson system evaluated in second order.

Adaptive Second-Order Total Variation: An Approach Aware of Slope Discontinuities

KAUST Repository

Lenzen, Frank; Becker, Florian; Lellmann, Jan

2013-01-01

Total variation (TV) regularization, originally introduced by Rudin, Osher and Fatemi in the context of image denoising, has become widely used in the field of inverse problems. Two major directions of modifications of the original approach were proposed later on. The first concerns adaptive variants of TV regularization, the second focuses on higher-order TV models. In the present paper, we combine the ideas of both directions by proposing adaptive second-order TV models, including one anisotropic model. Experiments demonstrate that introducing adaptivity results in an improvement of the reconstruction error. © 2013 Springer-Verlag.

Transient modeling of non-Fickian transport and first-order reaction using continuous time random walk

Science.gov (United States)

Burnell, Daniel K.; Hansen, Scott K.; Xu, Jie

2017-09-01

Contaminants in groundwater may experience a broad spectrum of velocities and multiple rates of mass transfer between mobile and immobile zones during transport. These conditions may lead to non-Fickian plume evolution which is not well described by the advection-dispersion equation (ADE). Simultaneously, many groundwater contaminants are degraded by processes that may be modeled as first-order decay. It is now known that non-Fickian transport and reaction are intimately coupled, with reaction affecting the transport operator. However, closed-form solutions for these important scenarios have not been published for use in applications. In this paper, we present four new Green's function analytic solutions in the uncoupled, uncorrelated continuous time random walk (CTRW) framework for reactive non-Fickian transport, corresponding to the quartet of conservative tracer solutions presented by Kreft and Zuber (1978) for Fickian transport. These consider pulse injection for both resident and flux concentration combined with detection in both resident and flux concentration. A pair of solutions for resident concentration temporal pulses with detection in both flux and resident concentration is also presented. We also derive the relationship between flux and resident concentration for non-Fickian transport with first-order reaction for this CTRW formulation. An explicit discussion of employment of the new solutions to model transport with arbitrary upgradient boundary conditions as well as mobile-immobile mass transfer is then presented. Using the new solutions, we show that first-order reaction has no effect on the anomalous spatial spreading rate of concentration profiles, but produces breakthrough curves at fixed locations that appear to have been generated by Fickian transport. Under the assumption of a Pareto CTRW transition distribution, we present a variety of numerical simulations including results showing coherence of our analytic solutions and CTRW particle

Multireference second order perturbation theory with a simplified treatment of dynamical correlation.

Science.gov (United States)

Xu, Enhua; Zhao, Dongbo; Li, Shuhua

2015-10-13

A multireference second order perturbation theory based on a complete active space configuration interaction (CASCI) function or density matrix renormalized group (DMRG) function has been proposed. This method may be considered as an approximation to the CAS/A approach with the same reference, in which the dynamical correlation is simplified with blocked correlated second order perturbation theory based on the generalized valence bond (GVB) reference (GVB-BCPT2). This method, denoted as CASCI-BCPT2/GVB or DMRG-BCPT2/GVB, is size consistent and has a similar computational cost as the conventional second order perturbation theory (MP2). We have applied it to investigate a number of problems of chemical interest. These problems include bond-breaking potential energy surfaces in four molecules, the spectroscopic constants of six diatomic molecules, the reaction barrier for the automerization of cyclobutadiene, and the energy difference between the monocyclic and bicyclic forms of 2,6-pyridyne. Our test applications demonstrate that CASCI-BCPT2/GVB can provide comparable results with CASPT2 (second order perturbation theory based on the complete active space self-consistent-field wave function) for systems under study. Furthermore, the DMRG-BCPT2/GVB method is applicable to treat strongly correlated systems with large active spaces, which are beyond the capability of CASPT2.

Second-order Born effect in coplanar doubly symmetric (e,2e) collisions for sodium

Energy Technology Data Exchange (ETDEWEB)

Wang, Yang; Jiao, Liguang [Center for Theoretical Atomic and Molecular Physics, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China); Zhou, Yajun, E-mail: yajunzhou2003@yahoo.com.cn [Center for Theoretical Atomic and Molecular Physics, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China)

2012-06-18

The second-order distorted wave Born approximation (DWBA) method is employed to investigate the triple differential cross sections (TDCS) of coplanar doubly symmetric (e,2e) collisions for alkali target sodium at excess energies of 6–60 eV. Comparing with the first-order DWBA calculations, the inclusion of second-order Born term in the scattering amplitude improves the degree of agreement with experiments, especially for backward scattering region of TDCS. This indicates the present second-order Born term is capable to give a reasonable correction to DWBA model in studying coplanar symmetric (e,2e) problems in low and intermediate energy range. -- Highlights: ► We consider second-order Born effect in (e,2e) collisions for sodium. ► Our second-order term gives a correct description on the multi scattering process. ► Our second-order DWBA model improves the agreement between theory and experiment.

Incorporating social groups' responses in a descriptive model for second- and higher-order impact identification

International Nuclear Information System (INIS)

Sutheerawatthana, Pitch; Minato, Takayuki

2010-01-01

The response of a social group is a missing element in the formal impact assessment model. Previous discussion of the involvement of social groups in an intervention has mainly focused on the formation of the intervention. This article discusses the involvement of social groups in a different way. A descriptive model is proposed by incorporating a social group's response into the concept of second- and higher-order effects. The model is developed based on a cause-effect relationship through the observation of phenomena in case studies. The model clarifies the process by which social groups interact with a lower-order effect and then generate a higher-order effect in an iterative manner. This study classifies social groups' responses into three forms-opposing, modifying, and advantage-taking action-and places them in six pathways. The model is expected to be used as an analytical tool for investigating and identifying impacts in the planning stage and as a framework for monitoring social groups' responses during the implementation stage of a policy, plan, program, or project (PPPPs).

SEARCHING FOR LOW WEIGHT PSEUDO-CODEWORDS

International Nuclear Information System (INIS)

Chertkov, Michael; Stepanov, Mikhail

2007-01-01

Belief Propagation (BP) and Linear Programming (LP) decodings of LDPC codes are discussed. The authors summarize results of instanton/pseudo-codeword approach developed for analysis of the error-floor domain of the codes. Instantons are special, code and decoding specific, configurations of the channel noise contributing most to the Frame-Error-Rate (FER). Instantons are decoded into pseudo-codewords. Instanton/pseudo-codeword with the lowest weight describes the largest Signal-to-Noise-Ratio (SNR) asymptotic of FER, while the whole spectra of the low weight instantons is descriptive of the FER vs. SNR profile in the extended error-floor domain. First, they describe a general optimization method that allows to find the instantons for any coding/decoding. Second, they introduce LP-specific pseudo-codeword search algorithm that allows efficient calculations of the pseudo-codeword spectra. Finally, they discuss results of combined BP/LP error-floor exploration experiments for two mode codes.

SEARCHING FOR LOW WEIGHT PSEUDO-CODEWORDS

Energy Technology Data Exchange (ETDEWEB)

CHERTKOV, MICHAEL [Los Alamos National Laboratory; STEPANOV, MIKHAIL [Los Alamos National Laboratory

2007-01-23

Belief Propagation (BP) and Linear Programming (LP) decodings of LDPC codes are discussed. The authors summarize results of instanton/pseudo-codeword approach developed for analysis of the error-floor domain of the codes. Instantons are special, code and decoding specific, configurations of the channel noise contributing most to the Frame-Error-Rate (FER). Instantons are decoded into pseudo-codewords. Instanton/pseudo-codeword with the lowest weight describes the largest Signal-to-Noise-Ratio (SNR) asymptotic of FER, while the whole spectra of the low weight instantons is descriptive of the FER vs. SNR profile in the extended error-floor domain. First, they describe a general optimization method that allows to find the instantons for any coding/decoding. Second, they introduce LP-specific pseudo-codeword search algorithm that allows efficient calculations of the pseudo-codeword spectra. Finally, they discuss results of combined BP/LP error-floor exploration experiments for two mode codes.

Second-order accurate volume-of-fluid algorithms for tracking material interfaces

International Nuclear Information System (INIS)

Pilliod, James Edward; Puckett, Elbridge Gerry

2004-01-01

We introduce two new volume-of-fluid interface reconstruction algorithms and compare the accuracy of these algorithms to four other widely used volume-of-fluid interface reconstruction algorithms. We find that when the interface is smooth (e.g., continuous with two continuous derivatives) the new methods are second-order accurate and the other algorithms are first-order accurate. We propose a design criteria for a volume-of-fluid interface reconstruction algorithm to be second-order accurate. Namely, that it reproduce lines in two space dimensions or planes in three space dimensions exactly. We also introduce a second-order, unsplit, volume-of-fluid advection algorithm that is based on a second-order, finite difference method for scalar conservation laws due to Bell, Dawson and Shubin. We test this advection algorithm by modeling several different interface shapes propagating in two simple incompressible flows and compare the results with the standard second-order, operator-split advection algorithm. Although both methods are second-order accurate when the interface is smooth, we find that the unsplit algorithm exhibits noticeably better resolution in regions where the interface has discontinuous derivatives, such as at corners

Adsorption of gold onto γ-aminopropyltriethoxysilane grafted coconut pith

International Nuclear Information System (INIS)

Usman, M.; Akhtar, J.

2017-01-01

This study was carried out to investigate adsorption kinetic and adsorption thermodynamics of Au(III) ions onto γ-aminopropyltriethoxysilane grafted coconut pith. The results from equilibrium adsorption were fitted in various adsorption isotherm models such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich and the best fit for the experimental data was Langmuir isotherm. The maximum adsorption capacity for virgin coconut pith (VCP) and the grafted coconut pith (GCP) were 256.41 and 285.59 mg/g, respectively. The kinetic data was verified using pseudo-first-order, pseudo-second-order, elovich equation and intraparticle diffusion model. The correlation results suggested that the pseudo-second-order model fits the experimental data well. A thermodynamic study revealed the endothermic nature of reaction due to positive enthalpy (?Ho) values and negative values of Gibbs free energy (?Go) describes the spontaneity of adsorption process. The regenerability of VCP and GCP adsorbents were investigated with NaOH (1.0 M).

On the model dependence of the determination of the strong coupling constant in second order QCD from e+e--annihilation into hadrons

International Nuclear Information System (INIS)

Achterberg, O.; D'Agostini, G.; Apel, W.D.; Engler, J.; Fluegge, G.; Forstbauer, B.; Fries, D.C.; Fues, W.; Gamerdinger, K.; Henkes, T.; Hopp, G.; Krueger, M.; Kuester, H.; Mueller, H.; Randoll, H.; Schmidt, G.; Schneider, H.; Boer, W. de; Buschhorn, G.; Grindhammer, G.; Grosse-Wiesmann, P.; Gunderson, B.; Kiesling, C.; Kotthaus, R.; Kruse, U.; Lierl, H.; Lueers, D.; Oberlack, H.; Schacht, P.; Bonneaud, G.; Colas, P.; Cordier, A.; Davier, M.; Fournier, D.; Grivaz, J.F.; Haissinski, J.; Journe, V.; Laplanche, F.; Le Diberder, F.; Mallik, U.; Ros, E.; Veillet, J.J.; Behrend, H.J.; Fenner, H.; Schachter, M.J.; Schroeder, V.; Sindt, H.

1983-12-01

Hadronic events obtained with the CELLO detector at PETRA are compared with second order QCD predictions using different models for the fragmentation of quarks and gluons into hadrons. We find that the model dependence in the determination of the strong coupling constant persists when going from first to second order QCD calculations. (orig.)

Validity of second order analysis of superdense matter

International Nuclear Information System (INIS)

Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.

1975-01-01

The limitations of relativistic calculations of the properties of superdense matter obtained from strictly second order terms is discussed. Extension of the model to overcome these limitations leads to serious complications which can only be overcome by a fully self-consistent treatment. (U.S.)

Pseudo-invariant Eigen-Operator Method for Solving Field-Intensity-Dependent Jaynes-Cummings Model

International Nuclear Information System (INIS)

Yu Taxi; Fan Hongyi

2010-01-01

By using the pseudo invariant eigen-operator method we analyze the field-intensity-dependent Jaynes-Gumming (JC) model. The pseudo-invariant eigen-operator is found in terms of the supersymmetric generators. The energy-level gap of this JC Hamiltonian is derived. This approach seems concise. (general)

Systemic Design for Second-Order Effects

Directory of Open Access Journals (Sweden)

Evan Barba

2017-04-01

Full Text Available Second-order effects refer to changes within a system that are the result of changes made somewhere else in the system (the first-order effects. Second-order effects can occur at different spatial, temporal, or organizational scales from the original interventions, and are difficult to control. Some organizational theorists suggest that careful management of feedback processes can facilitate controlled change from one organizational configuration to another. Recognizing that skill in managing feedback processes is a core competency of design suggests that design skills are potentially useful tools in achieving organizational change. This paper describes a case study in which a co-design methodology was used to control the second-order effects resulting from a classroom intervention to create organizational change. This approach is then theorized as the Instigator Systems approach.

Models of direct reactions and quantum pre-equilibrium for nucleon scattering on spherical nuclei

International Nuclear Information System (INIS)

Dupuis, M.

2006-01-01

When a nucleon collides with a target nucleus, several reactions may occur: elastic and inelastic scatterings, charge exchange... In order to describe these reactions, different models are involved: the direct reactions, pre-equilibrium and compound nucleus models. Our goal is to study, within a quantum framework and without any adjustable parameter, the direct and pre-equilibrium reactions for nucleons scatterings off double closed-shell nuclei. We first consider direct reactions: we are studying nucleon scattering with the Melbourne G-matrix, which represents the interaction between the projectile and one target nucleon, and with random phase approximation (RPA) wave functions which describe all target states. This is a fully microscopic approach since no adjustable parameters are involved. A second part is dedicated to the study of nucleon inelastic scattering for large energy transfer which necessarily involves the pre-equilibrium mechanism. Several models have been developed in the past to deal with pre-equilibrium. They start from the Born expansion of the transition amplitude which is associated to the inelastic process and they use several approximations which have not yet been tested. We have achieved some comparisons between second order cross sections which have been calculated with and without these approximations. Our results allow us to criticize some of these approximations and give several directions to improve the quantum pre-equilibrium models. (author)

Optimization of an intracavity Q-switched solid-state second order Raman laser

Science.gov (United States)

Chen, Zhiqiong; Fu, Xihong; Peng, Hangyu; Zhang, Jun; Qin, Li; Ning, Yongqiang

2017-01-01

In this paper, the model of an intracavity Q-switched second order Raman laser is established, the characteristics of the output 2nd Stokes are simulated. The dynamic balance mechanism among intracavity conversion rates of stimulated emission, first order Raman and second order Raman is obtained. Finally, optimization solutions for increasing output 2nd Stokes pulse energy are proposed.

Pseudo-Newtonian planar circular restricted 3-body problem

International Nuclear Information System (INIS)

Dubeibe, F.L.; Lora-Clavijo, F.D.; González, Guillermo A.

2017-01-01

We study the dynamics of the planar circular restricted three-body problem in the context of a pseudo-Newtonian approximation. By using the Fodor–Hoenselaers–Perjés procedure, we perform an expansion in the mass potential of a static massive spherical source up to the first non-Newtonian term, giving place to a gravitational potential that includes first-order general relativistic effects. With this result, we model a system composed by two pseudo-Newtonian primaries describing circular orbits around their common center of mass, and a test particle orbiting the system in the equatorial plane. The dynamics of the new system of equations is studied in terms of the Poincaré section method and the Lyapunov exponents, where the introduction of a new parameter ϵ, allows us to observe the transition from the Newtonian to the pseudo-Newtonian regime. We show that when the Jacobian constant is fixed, a chaotic orbit in the Newtonian regime can be either chaotic or regular in the pseudo-Newtonian approach. As a general result, we find that most of the pseudo-Newtonian configurations are less stable than their Newtonian equivalent.

Pseudo-Newtonian planar circular restricted 3-body problem

Energy Technology Data Exchange (ETDEWEB)

Dubeibe, F.L., E-mail: fldubeibem@unal.edu.co [Facultad de Ciencias Humanas y de la Educación, Universidad de los Llanos, Villavicencio (Colombia); Grupo de Investigación en Relatividad y Gravitación, Escuela de Física, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia); Lora-Clavijo, F.D., E-mail: fadulora@uis.edu.co [Grupo de Investigación en Relatividad y Gravitación, Escuela de Física, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia); González, Guillermo A., E-mail: guillermo.gonzalez@saber.uis.edu.co [Grupo de Investigación en Relatividad y Gravitación, Escuela de Física, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia)

2017-02-12

We study the dynamics of the planar circular restricted three-body problem in the context of a pseudo-Newtonian approximation. By using the Fodor–Hoenselaers–Perjés procedure, we perform an expansion in the mass potential of a static massive spherical source up to the first non-Newtonian term, giving place to a gravitational potential that includes first-order general relativistic effects. With this result, we model a system composed by two pseudo-Newtonian primaries describing circular orbits around their common center of mass, and a test particle orbiting the system in the equatorial plane. The dynamics of the new system of equations is studied in terms of the Poincaré section method and the Lyapunov exponents, where the introduction of a new parameter ϵ, allows us to observe the transition from the Newtonian to the pseudo-Newtonian regime. We show that when the Jacobian constant is fixed, a chaotic orbit in the Newtonian regime can be either chaotic or regular in the pseudo-Newtonian approach. As a general result, we find that most of the pseudo-Newtonian configurations are less stable than their Newtonian equivalent.

Inflation and pseudo-Goldstone Higgs boson

DEFF Research Database (Denmark)

Alanne, Tommi; Sannino, Francesco; Tenkanen, Tommi

2017-01-01

We consider inflation within a model framework where the Higgs boson arises as a pseudo-Goldstone boson associated with the breaking of a global symmetry at a scale significantly larger than the electroweak one. We show that in such a model the scalar self-couplings can be parametrically suppressed...... and, consequently, the nonminimal couplings to gravity can be of order one or less, while the inflationary predictions of the model remain compatible with the precision cosmological observations. Furthermore, in the model we study, the existence of the electroweak scale is entirely due to the inflaton...

Consensus of second-order multi-agent dynamic systems with quantized data

Energy Technology Data Exchange (ETDEWEB)

Guan, Zhi-Hong, E-mail: zhguan@mail.hust.edu.cn [Department of Control Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Meng, Cheng [Department of Control Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Liao, Rui-Quan [Petroleum Engineering College,Yangtze University, Jingzhou, 420400 (China); Zhang, Ding-Xue, E-mail: zdx7773@163.com [Petroleum Engineering College,Yangtze University, Jingzhou, 420400 (China)

2012-01-09

The consensus problem of second-order multi-agent systems with quantized link is investigated in this Letter. Some conditions are derived for the quantized consensus of the second-order multi-agent systems by the stability theory. Moreover, a result characterizing the relationship between the eigenvalues of the Laplacians matrix and the quantized consensus is obtained. Examples are given to illustrate the theoretical analysis. -- Highlights: ► A second-order multi-agent model with quantized data is proposed. ► Two sufficient and necessary conditions are obtained. ► The relationship between the eigenvalues of the Laplacians matrix and the quantized consensus is discovered.

First- and second-order processing in transient stereopsis.

Science.gov (United States)

Edwards, M; Pope, D R; Schor, C M

2000-01-01

Large-field stimuli were used to investigate the interaction of first- and second-order pathways in transient-stereo processing. Stimuli consisted of sinewave modulations in either the mean luminance (first-order stimulus) or the contrast (second-order stimulus) of a dynamic-random-dot field. The main results of the present study are that: (1) Depth could be extracted with both the first-order and second-order stimuli; (2) Depth could be extracted from dichoptically mixed first- and second-order stimuli, however, the same stimuli, when presented as a motion sequence, did not result in a motion percept. Based upon these findings we conclude that the transient-stereo system processes both first- and second-order signals, and that these two signals are pooled prior to the extraction of transient depth. This finding of interaction between first- and second-order stereoscopic processing is different from the independence that has been found with the motion system.

Delayed allergy-like reactions to X-ray contrast media. Second expert meeting

International Nuclear Information System (INIS)

Sviridov, N.K

1998-01-01

Materials of the second expert meeting of medical radiologists of USA, Germany, and Japan concerning delayed allergy-like reactions to X-ray contrast media (XRCM) are briefly considered. Attention is paid to the experimental and clinical data on the application of nonionic dimers, pathophysiological and immunological aspects of the reaction to XRCM, certain models and hypotheses, allergy to XRCM

Weak second-order splitting schemes for Lagrangian Monte Carlo particle methods for the composition PDF/FDF transport equations

International Nuclear Information System (INIS)

Wang Haifeng; Popov, Pavel P.; Pope, Stephen B.

2010-01-01

We study a class of methods for the numerical solution of the system of stochastic differential equations (SDEs) that arises in the modeling of turbulent combustion, specifically in the Monte Carlo particle method for the solution of the model equations for the composition probability density function (PDF) and the filtered density function (FDF). This system consists of an SDE for particle position and a random differential equation for particle composition. The numerical methods considered advance the solution in time with (weak) second-order accuracy with respect to the time step size. The four primary contributions of the paper are: (i) establishing that the coefficients in the particle equations can be frozen at the mid-time (while preserving second-order accuracy), (ii) examining the performance of three existing schemes for integrating the SDEs, (iii) developing and evaluating different splitting schemes (which treat particle motion, reaction and mixing on different sub-steps), and (iv) developing the method of manufactured solutions (MMS) to assess the convergence of Monte Carlo particle methods. Tests using MMS confirm the second-order accuracy of the schemes. In general, the use of frozen coefficients reduces the numerical errors. Otherwise no significant differences are observed in the performance of the different SDE schemes and splitting schemes.

Modulation masking produced by second-order modulators

DEFF Research Database (Denmark)

Füllgrabe, Christian; Moore, Brian C.J.; Demany, Laurent

2005-01-01

Recent studies suggest that an auditory nonlinearity converts second-order sinusoidal amplitude modulation (SAM) (i.e., modulation of SAM depth) into a first-order SAM component, which contributes to the perception of second-order SAM. However, conversion may also occur in other ways such as coch...

Simulation of a directed random-walk model: the effect of pseudo-random-number correlations

OpenAIRE

Shchur, L. N.; Heringa, J. R.; Blöte, H. W. J.

1996-01-01

We investigate the mechanism that leads to systematic deviations in cluster Monte Carlo simulations when correlated pseudo-random numbers are used. We present a simple model, which enables an analysis of the effects due to correlations in several types of pseudo-random-number sequences. This model provides qualitative understanding of the bias mechanism in a class of cluster Monte Carlo algorithms.

Reaction Order Ambiguity in Integrated Rate Plots

Science.gov (United States)

Lee, Joe

2008-01-01

Integrated rate plots are frequently used in reaction kinetics to determine orders of reactions. It is often emphasised, when using this methodology in practice, that it is necessary to monitor the reaction to a substantial fraction of completion for these plots to yield unambiguous orders. The present article gives a theoretical and statistical…

Diabatic models with transferrable parameters for generalized chemical reactions

International Nuclear Information System (INIS)

Reimers, Jeffrey R; McKemmish, Laura K; McKenzie, Ross H; Hush, Noel S

2017-01-01

Diabatic models applied to adiabatic electron-transfer theory yield many equations involving just a few parameters that connect ground-state geometries and vibration frequencies to excited-state transition energies and vibration frequencies to the rate constants for electron-transfer reactions, utilizing properties of the conical-intersection seam linking the ground and excited states through the Pseudo Jahn-Teller effect. We review how such simplicity in basic understanding can also be obtained for general chemical reactions. The key feature that must be recognized is that electron-transfer (or hole transfer) processes typically involve one electron (hole) moving between two orbitals, whereas general reactions typically involve two electrons or even four electrons for processes in aromatic molecules. Each additional moving electron leads to new high-energy but interrelated conical-intersection seams that distort the shape of the critical lowest-energy seam. Recognizing this feature shows how conical-intersection descriptors can be transferred between systems, and how general chemical reactions can be compared using the same set of simple parameters. Mathematical relationships are presented depicting how different conical-intersection seams relate to each other, showing that complex problems can be reduced into an effective interaction between the ground-state and a critical excited state to provide the first semi-quantitative implementation of Shaik’s “twin state” concept. Applications are made (i) demonstrating why the chemistry of the first-row elements is qualitatively so different to that of the second and later rows, (ii) deducing the bond-length alternation in hypothetical cyclohexatriene from the observed UV spectroscopy of benzene, (iii) demonstrating that commonly used procedures for modelling surface hopping based on inclusion of only the first-derivative correction to the Born-Oppenheimer approximation are valid in no region of the chemical

Details of modelling HTR core physics: the use of pseudo nuclide traces

International Nuclear Information System (INIS)

Kuijper, J.C.; Oppe, J.; Haas, J.B.M. de; Da Cruz, D.F.

2003-01-01

At present most combined neutronic and thermal hydraulic analyses of reactors, and the HTR is no exception, are being performed by codes employing few-group (typically 2-group) neutronics on the basis of parametrized few-group macroscopic (and microscopic) cross sections for homogenized areas, depending on quantities like irradiation (fuel only), 135 Xe concentration, temperature, etc. The irradiation parameter (time-integrated power per unit initial heavy metal mass) is sufficient for keeping track of the evolution of areas containing fuel. However, the use of the same parameter in areas without fuel, e.g. containing burnable poison, requires some special provisions. This can be met by the introduction of pseudo nuclides, with very specific cross sections and reaction chains, in the procedure to generate the parametrized few-group cross sections. It is shown that the time-evolution of a non-fuelled burnable poison area, as calculated by the 2-group (HTR) reactor code PANTHERMIX employing pseudo nuclides, compares well to the time-evolution obtained from an explicit burnup calculation by the WIMS8A/SNAP code. Examples are also shown using the pseudo nuclide method to keep track of the fast fluence (time-integrated flux above 0.1 MeV) in a continuous reload pebble-bed HTR reactor calculation by PANTHERMIX. Although the present implementation of the pseudo nuclide method exhibits some peculiarities connected to the specific codes in use (WIMS8A and PANTHERMIX) it is considered to be sufficiently general to be applicable in other code suites, requiring only limited modifications. (authors)

Details of modelling HTR core physics: the use of pseudo nuclide traces

Energy Technology Data Exchange (ETDEWEB)

Kuijper, J.C.; Oppe, J.; Haas, J.B.M. de; Da Cruz, D.F. [Nuclear Research and consultancy Group (NRG), Petten (Netherlands)

2003-07-01

At present most combined neutronic and thermal hydraulic analyses of reactors, and the HTR is no exception, are being performed by codes employing few-group (typically 2-group) neutronics on the basis of parametrized few-group macroscopic (and microscopic) cross sections for homogenized areas, depending on quantities like irradiation (fuel only), {sup 135}Xe concentration, temperature, etc. The irradiation parameter (time-integrated power per unit initial heavy metal mass) is sufficient for keeping track of the evolution of areas containing fuel. However, the use of the same parameter in areas without fuel, e.g. containing burnable poison, requires some special provisions. This can be met by the introduction of pseudo nuclides, with very specific cross sections and reaction chains, in the procedure to generate the parametrized few-group cross sections. It is shown that the time-evolution of a non-fuelled burnable poison area, as calculated by the 2-group (HTR) reactor code PANTHERMIX employing pseudo nuclides, compares well to the time-evolution obtained from an explicit burnup calculation by the WIMS8A/SNAP code. Examples are also shown using the pseudo nuclide method to keep track of the fast fluence (time-integrated flux above 0.1 MeV) in a continuous reload pebble-bed HTR reactor calculation by PANTHERMIX. Although the present implementation of the pseudo nuclide method exhibits some peculiarities connected to the specific codes in use (WIMS8A and PANTHERMIX) it is considered to be sufficiently general to be applicable in other code suites, requiring only limited modifications. (authors)

Carrageenan-based semi-IPN nanocomposite hydrogels: Swelling kinetic and slow release of sequestrene Fe 138 fertilizer

Directory of Open Access Journals (Sweden)

Mohammad Kazem Bahrami

2016-09-01

Full Text Available Nanocomposite hydrogels based on kappa-carrageenan were synthesized by incorporating natural sodium montmorillonite (Cloisite nanoclay. Acrylamide (AAm and methylenebisacrylamide (MBA were used as a monomer and a crosslinker, respectively. Effects of reaction variables on the swelling kinetics were studied. The results revealed that the rate of swelling for nanocomposites with high content of MBA was higher than those of nanocomposites consisting of low content of MBA. Similar to the effect of MBA, the rate of swelling enhanced as the carrageenan content was decreased. The influence of clay content on swelling rate was not remarkable. The experimental swelling data were evaluated by pseudo-first-order and pseudo-second-order kinetic models. The swelling data described well by pseudo-second-order kinetic model. Sequestrene Fe 138 (Sq as an agrochemical was loaded into nanocomposites and releasing of this active agent from nanocomposites was studied. The clay-free hydrogel released the whole loaded Sq; whereas the presence of clay restricted the release of Sq.

Adsorption of phenolic compound by aged-refuse

Energy Technology Data Exchange (ETDEWEB)

Chai Xiaoli [State Key Laboratory of Pollution Control and Resource Reuse, School of Enviromental Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092 (China)]. E-mail: xlchai@mail.tongji.edu.cn; Zhao Youcai [State Key Laboratory of Pollution Control and Resource Reuse, School of Enviromental Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092 (China)

2006-09-01

The adsorption of phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol by aged-refuse has been studied. Adsorption isotherms have been determined for phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol and the data fits well to the Freundlich equation. The chlorinated phenols are absorbed more strongly than the phenol and the adsorption capacity has an oblivious relationship with the numbers and the position of chlorine subsistent. The experiment data suggests that both the partition function and the chemical adsorption involve in the adsorption process. Pseudo-first-order and pseudo-second-order model were applied to investigate the kinetics of the adsorption and the results show that it fit the pseudo-second-order model. More than one step involves in the adsorption process and the overall rate of the adsorption process appears to be controlled by the chemical reaction. The thermodynamic analysis indicates that the adsorption is spontaneous and endothermic.

Adsorption of phenolic compound by aged-refuse

International Nuclear Information System (INIS)

Chai Xiaoli; Zhao Youcai

2006-01-01

The adsorption of phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol by aged-refuse has been studied. Adsorption isotherms have been determined for phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol and the data fits well to the Freundlich equation. The chlorinated phenols are absorbed more strongly than the phenol and the adsorption capacity has an oblivious relationship with the numbers and the position of chlorine subsistent. The experiment data suggests that both the partition function and the chemical adsorption involve in the adsorption process. Pseudo-first-order and pseudo-second-order model were applied to investigate the kinetics of the adsorption and the results show that it fit the pseudo-second-order model. More than one step involves in the adsorption process and the overall rate of the adsorption process appears to be controlled by the chemical reaction. The thermodynamic analysis indicates that the adsorption is spontaneous and endothermic

A cellular automata approach to chemical reactions : 1 reaction controlled systems

NARCIS (Netherlands)

Korte, de A.C.J.; Brouwers, H.J.H.

2013-01-01

A direct link between the chemical reaction controlled (shrinking core) model and cellular automata, to study the dissolution of particles, is derived in this paper. Previous research on first and second order reactions is based on the concentration of the reactant. The present paper describes the

Removal of dieldrin from aqueous solution by a novel triolein-embedded composite adsorbent

International Nuclear Information System (INIS)

Ru Jia; Liu Huijuan; Qu Jiuhui; Wang Aimin; Dai Ruihua

2007-01-01

In this study, a novel triolein-embedded activated carbon composite adsorbent (CA-T) was prepared and applied for the adsorption and removal of dieldrin from aqueous systems. Experiments were carried out to investigate the adsorption behavior of dieldrin on CA-T, including adsorption isotherms, adsorption kinetics, the influence of initial concentration, temperature, shaking speed, pH and the addition of humic acid (HA) on adsorption. The adsorption isotherms accorded with Freundlich equation. Three kinetics models, including pseudo-first-order, pseudo-second-order and intraparticle diffusion models, were used to fit the experimental data. By comparing the correlation coefficients, it was found that both pseudo-second-order and intraparticle diffusion models were used to well describe the adsorption of dieldrin on CA-T. The addition of HA had little effect on dieldrin adsorption by CA-T. Results indicated that CA-T appeared to be a promising adsorbent for removing lipophilic dieldrin in trace amount, which was advantageous over pure granular activated carbon (GAC). The adsorption rate increased with increasing shaking speed, initial concentration and temperature, and remained almost unchanged in the pH range of 4-8. Thermodynamic calculations indicated that the adsorption reaction was spontaneous with a high affinity and the adsorption was an endothermic reaction

Synchronization from second order network connectivity statistics

Directory of Open Access Journals (Sweden)

Liqiong eZhao

2011-07-01

Full Text Available We investigate how network structure can influence the tendency for a neuronal network to synchronize, or its synchronizability, independent of the dynamical model for each neuron. The synchrony analysis takes advantage of the framework of second order networks (SONETs, which defines four second order connectivity statistics based on the relative frequency of two-connection network motifs. The analysis identifies two of these statistics, convergent connections and chain connections, as highly influencing the synchrony. Simulations verify that synchrony decreases with the frequency of convergent connections and increases with the frequency of chain connections. These trends persist with simulations of multiple models for the neuron dynamics and for different types of networks. Surprisingly, divergent connections, which determine the fraction of shared inputs, do not strongly influence the synchrony. The critical role of chains, rather than divergent connections, in influencing synchrony can be explained by a pool and redistribute mechanism. The pooling of many inputs averages out independent fluctuations, amplifying weak correlations in the inputs. With increased chain connections, neurons with many inputs tend to have many outputs. Hence, chains ensure that the amplified correlations in the neurons with many inputs are redistributed throughout the network, enhancing the development of synchrony across the network.

Influence of time delay on fractional-order PI-controlled system for a second-order oscillatory plant model with time delay

Directory of Open Access Journals (Sweden)

Sadalla Talar

2017-12-01

Full Text Available The paper aims at presenting the influence of an open-loop time delay on the stability and tracking performance of a second-order open-loop system and continuoustime fractional-order PI controller. The tuning method of this controller is based on Hermite- Biehler and Pontryagin theorems, and the tracking performance is evaluated on the basis of two integral performance indices, namely IAE and ISE. The paper extends the results and methodology presented in previous work of the authors to analysis of the influence of time delay on the closed-loop system taking its destabilizing properties into account, as well as concerning possible application of the presented results and used models.

Second-Order Controllability of Multi-Agent Systems with Multiple Leaders

International Nuclear Information System (INIS)

Liu Bo; Han Xiao; Shi Yun-Tao; Su Hou-Sheng

2016-01-01

This paper proposes a new second-order continuous-time multi-agent model and analyzes the controllability of second-order multi-agent system with multiple leaders based on the asymmetric topology. This paper considers the more general case: velocity coupling topology is different from location coupling topology. Some sufficient and necessary conditions are presented for the controllability of the system with multiple leaders. In addition, the paper studies the controllability of the system with velocity damping gain. Simulation results are given to illustrate the correctness of theoretical results. (paper)

Second Order Optimality in Markov Decision Chains

Czech Academy of Sciences Publication Activity Database

Sladký, Karel

2017-01-01

Roč. 53, č. 6 (2017), s. 1086-1099 ISSN 0023-5954 R&D Projects: GA ČR GA15-10331S Institutional support: RVO:67985556 Keywords : Markov decision chains * second order optimality * optimalilty conditions for transient, discounted and average models * policy and value iterations Subject RIV: BB - Applied Statistics, Operational Research OBOR OECD: Statistics and probability Impact factor: 0.379, year: 2016 http://library.utia.cas.cz/separaty/2017/E/sladky-0485146.pdf

Second Order Impulsive Retarded Differential Inclusions with Nonlocal Conditions

Directory of Open Access Journals (Sweden)

Hernán R. Henríquez

2014-01-01

Full Text Available In this work we establish some existence results for abstract second order Cauchy problems modeled by a retarded differential inclusion involving nonlocal and impulsive conditions. Our results are obtained by using fixed point theory for the measure of noncompactness.

Kinetic parameters of hydroprocessing reactions in a flow reactor

Energy Technology Data Exchange (ETDEWEB)

Raychaudhuri, U.; Banerjee, T.S.; Ghar, R.N. (Indian Institute of Technology, Kharagpur (India))

1994-01-01

The change in distillation properties of a blend of light and heavy distillates over a commercial hydrotreating catalyst was studied using a small packed bed reactor. The results were interpreted assuming a pseudo-component model that took into account the physical and chemical complexity of the system. A first order series-parallel reaction mechanism was found to be valid for the operating conditions involved. Pore diffusion effects were also taken into consideration. 8 refs., 7 figs., 1 tab.

A semi-implicit, second-order-accurate numerical model for multiphase underexpanded volcanic jets

Directory of Open Access Journals (Sweden)

S. Carcano

2013-11-01

Full Text Available An improved version of the PDAC (Pyroclastic Dispersal Analysis Code, Esposti Ongaro et al., 2007 numerical model for the simulation of multiphase volcanic flows is presented and validated for the simulation of multiphase volcanic jets in supersonic regimes. The present version of PDAC includes second-order time- and space discretizations and fully multidimensional advection discretizations in order to reduce numerical diffusion and enhance the accuracy of the original model. The model is tested on the problem of jet decompression in both two and three dimensions. For homogeneous jets, numerical results are consistent with experimental results at the laboratory scale (Lewis and Carlson, 1964. For nonequilibrium gas–particle jets, we consider monodisperse and bidisperse mixtures, and we quantify nonequilibrium effects in terms of the ratio between the particle relaxation time and a characteristic jet timescale. For coarse particles and low particle load, numerical simulations well reproduce laboratory experiments and numerical simulations carried out with an Eulerian–Lagrangian model (Sommerfeld, 1993. At the volcanic scale, we consider steady-state conditions associated with the development of Vulcanian and sub-Plinian eruptions. For the finest particles produced in these regimes, we demonstrate that the solid phase is in mechanical and thermal equilibrium with the gas phase and that the jet decompression structure is well described by a pseudogas model (Ogden et al., 2008. Coarse particles, on the other hand, display significant nonequilibrium effects, which associated with their larger relaxation time. Deviations from the equilibrium regime, with maximum velocity and temperature differences on the order of 150 m s−1 and 80 K across shock waves, occur especially during the rapid acceleration phases, and are able to modify substantially the jet dynamics with respect to the homogeneous case.

Recursive belief manipulation and second-order false-beliefs

DEFF Research Database (Denmark)

Braüner, Torben; Blackburn, Patrick Rowan; Polyanskaya, Irina

2016-01-01

it indicate that a more fundamental *conceptual change* has taken place? In this paper we extend Braüner's hybrid-logical analysis of first-order false-belief tasks to the second-order case, and argue that our analysis supports a version of the conceptual change position.......The literature on first-order false-belief is extensive, but less is known about the second-order case. The ability to handle second-order false-beliefs correctly seems to mark a cognitively significant step, but what is its status? Is it an example of *complexity only* development, or does...

Lagrangian analysis of invariant third-order equations of motion in relativistic classical particle mechanics

International Nuclear Information System (INIS)

Matsyuk, R.Ya.

1985-01-01

The problem on the existence of the invariant third-order Euler-Poisson equations in the pseudo-Euclidean space is investigated. The locally variational problem is determined by the Lagrangian density over the space of the second-order jets. The one - parameter family of the invariant third-order Euler-Poisson equations is groved to be the only one in the three-dimensional pseudo-Euclidean space. No invariant third-order Euler-Poisson equations exist in the four-dimensional pseudo-Euclidean space. It is shown that the Mathisson equation and the equation of geodesic circles in particular cases may be considered in the context of the Ostrogradiskij mechanics and the Kavaguchi geometry

[Influence of pH on Kinetics of Anilines Oxidation by Permanganate].

Science.gov (United States)

Wang, Hui; Sun, Bo; Guan, Xiao-hong

2016-02-15

To investigate the effect of pH on the oxidation of anilines by potassium permanganate, aniline and p-Chloroaniline were taken as the target contaminants, and the experiments were conducted under the condition with potassium permanganate in excess over a wide pH range. The reaction displayed remarkable autocatalysis, which was presumably ascribed to the formation of complexes by the in situ generated MnOx and the target contaminants on its surface, and thereby improved the oxidation rate of the target contaminants by permanganate. The reaction kinetics was fitted with the pseudo-first-order kinetics at different pH to obtain the pseudo-first-order reaction constants (k(obs)). The second-order rate constants calculated from permanganate concentration and k,b, increased with the increase of pH and reached the maximum near their respective pKa, after which they decreased gradually. This tendency is called parabola-like shaped pH-rate profile. The second-order rate constants between permanganate and anilines were well fitted by the proton transfer model proposed by us in previous work.

A variable reaction rate model for chlorine decay in drinking water due to the reaction with dissolved organic matter.

Science.gov (United States)

Hua, Pei; Vasyukova, Ekaterina; Uhl, Wolfgang

2015-05-15

A second order kinetic model for simulating chlorine decay in bulk water due to the reaction with dissolved organic matter (DOM) was developed. It takes into account the decreasing reactivity of dissolved organic matter using a variable reaction rate coefficient (VRRC) which decreases with an increasing conversion. The concentration of reducing species is surrogated by the maximum chlorine demand. Temperature dependency, respectively, is described by the Arrhenius-relationship. The accuracy and adequacy of the proposed model to describe chlorine decay in bulk water were evaluated and shown for very different waters and different conditions such as water mixing or rechlorination by applying statistical tests. It is thus very well suited for application in water quality modeling for distribution systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

High performance maleated lignocellulose epicarp fibers for copper ion removal

Directory of Open Access Journals (Sweden)

A. P. Vieira

2014-03-01

Full Text Available Natural lignocellulosic fiber epicarp extracted from the babassu coconut (Orbignya speciosa was chemically modified through reaction with molten maleic anhydride without solvent, with incorporation of 189.34 mg g-1 of carboxylic acid groups into the biopolymer structure. The success of this reaction was also confirmed by the presence of carboxylic acid bands at 1741 and 1164 cm-1 in the infrared spectrum. Identically, the same group is observed through 13C NMR CP/MAS in the solid state, via high field signals in the 167 pm region. Both the precursor and the immobilized maleated biopolymers presented nearly the same thermal stability and similar crystallinity to cellulose. However, the pendant carboxylic groups have the ability to remove copper with maximum sorption through a batchwise process at pH 6.0, as expected from the point of zero charge, determined to be 6.45. The sorption kinetic data were fitted to pseudo-first order, pseudo-second order, Elovich-chemisorption and intra-particle diffusion models and the equilibrium data were fitted to the Langmuir, the Freundlich and Tenkim isotherm models. Taking into account a statistical error function and determination coefficients, the data were fit to the pseudo-first and pseudo-second order kinetic and Langmuir isotherm models, with a maximum sorption capacity of copper ions of 55.09 mg g-1. This value suggests the application of this biopolymer with incorporated carboxylate groups as a favorable agent for copper removal from appropriate systems.

Pseudo-populations a basic concept in statistical surveys

CERN Document Server

Quatember, Andreas

2015-01-01

This book emphasizes that artificial or pseudo-populations play an important role in statistical surveys from finite universes in two manners: firstly, the concept of pseudo-populations may substantially improve users’ understanding of various aspects in the sampling theory and survey methodology; an example of this scenario is the Horvitz-Thompson estimator. Secondly, statistical procedures exist in which pseudo-populations actually have to be generated. An example of such a scenario can be found in simulation studies in the field of survey sampling, where close-to-reality pseudo-populations are generated from known sample and population data to form the basis for the simulation process. The chapters focus on estimation methods, sampling techniques, nonresponse, questioning designs and statistical disclosure control.This book is a valuable reference in understanding the importance of the pseudo-population concept and applying it in teaching and research.

Building a pseudo-atomic model of the anaphase-promoting complex

International Nuclear Information System (INIS)

Kulkarni, Kiran; Zhang, Ziguo; Chang, Leifu; Yang, Jing; Fonseca, Paula C. A. da; Barford, David

2013-01-01

This article describes an example of molecular replacement in which atomic models are used to interpret electron-density maps determined using single-particle electron-microscopy data. The anaphase-promoting complex (APC/C) is a large E3 ubiquitin ligase that regulates progression through specific stages of the cell cycle by coordinating the ubiquitin-dependent degradation of cell-cycle regulatory proteins. Depending on the species, the active form of the APC/C consists of 14–15 different proteins that assemble into a 20-subunit complex with a mass of approximately 1.3 MDa. A hybrid approach of single-particle electron microscopy and protein crystallography of individual APC/C subunits has been applied to generate pseudo-atomic models of various functional states of the complex. Three approaches for assigning regions of the EM-derived APC/C density map to specific APC/C subunits are described. This information was used to dock atomic models of APC/C subunits, determined either by protein crystallography or homology modelling, to specific regions of the APC/C EM map, allowing the generation of a pseudo-atomic model corresponding to 80% of the entire complex

Introduction to fractional and pseudo-differential equations with singular symbols

CERN Document Server

Umarov, Sabir

2015-01-01

The book systematically presents the theories of pseudo-differential operators with symbols singular in dual variables, fractional order derivatives, distributed and variable order fractional derivatives, random walk approximants, and applications of these theories to various initial and multi-point boundary value problems for pseudo-differential equations. Fractional Fokker-Planck-Kolmogorov equations associated with a large class of stochastic processes are presented. A complex version of the theory of pseudo-differential operators with meromorphic symbols based on the recently introduced complex Fourier transform is developed and applied for initial and boundary value problems for systems of complex differential and pseudo-differential equations.

Polynomial constitutive model for shape memory and pseudo elasticity

International Nuclear Information System (INIS)

Savi, M.A.; Kouzak, Z.

1995-01-01

This paper reports an one-dimensional phenomenological constitutive model for shape memory and pseudo elasticity using a polynomial expression for the free energy which is based on the classical Devonshire theory. This study identifies the main characteristics of the classical theory and introduces a simple modification to obtain better results. (author). 9 refs., 6 figs

Measuring order in disordered systems and disorder in ordered systems: Random matrix theory for isotropic and nematic liquid crystals and its perspective on pseudo-nematic domains

Science.gov (United States)

Zhao, Yan; Stratt, Richard M.

2018-05-01

Surprisingly long-ranged intermolecular correlations begin to appear in isotropic (orientationally disordered) phases of liquid crystal forming molecules when the temperature or density starts to close in on the boundary with the nematic (ordered) phase. Indeed, the presence of slowly relaxing, strongly orientationally correlated, sets of molecules under putatively disordered conditions ("pseudo-nematic domains") has been apparent for some time from light-scattering and optical-Kerr experiments. Still, a fully microscopic characterization of these domains has been lacking. We illustrate in this paper how pseudo-nematic domains can be studied in even relatively small computer simulations by looking for order-parameter tensor fluctuations much larger than one would expect from random matrix theory. To develop this idea, we show that random matrix theory offers an exact description of how the probability distribution for liquid-crystal order parameter tensors converges to its macroscopic-system limit. We then illustrate how domain properties can be inferred from finite-size-induced deviations from these random matrix predictions. A straightforward generalization of time-independent random matrix theory also allows us to prove that the analogous random matrix predictions for the time dependence of the order-parameter tensor are similarly exact in the macroscopic limit, and that relaxation behavior of the domains can be seen in the breakdown of the finite-size scaling required by that random-matrix theory.

Linear Matrix Inequalities for Analysis and Control of Linear Vector Second-Order Systems

DEFF Research Database (Denmark)

Adegas, Fabiano Daher; Stoustrup, Jakob

2015-01-01

the Lyapunov matrix and the system matrices by introducing matrix multipliers, which potentially reduce conservativeness in hard control problems. Multipliers facilitate the usage of parameter-dependent Lyapunov functions as certificates of stability of uncertain and time-varying vector second-order systems......SUMMARY Many dynamical systems are modeled as vector second-order differential equations. This paper presents analysis and synthesis conditions in terms of LMI with explicit dependence in the coefficient matrices of vector second-order systems. These conditions benefit from the separation between....... The conditions introduced in this work have the potential to increase the practice of analyzing and controlling systems directly in vector second-order form. Copyright © 2014 John Wiley & Sons, Ltd....

Modeling and Elucidation of the Kinetics of Multiple Consecutive Photoreactions AB4(4Φ) With Φ-order Kinetics. Application to the Photodegradation of Riboflavin.

Science.gov (United States)

Maafi, Mounir; Maafi, Wassila

2016-12-01

New semi-empirical rate-law system of equations is proposed for the first time for consecutive photoreactions that involve up to 4 photoreaction steps, AB 4 (4Φ). The equation system was developed, tested, and validated against synthetic kinetic traces generated by fifth-order Runge-Kutta calculations. The model accurately fitted the kinetic traces of Riboflavin photodegradation in ethanol which decomposes via the AB 2 (2Φ) mechanism involving 2 consecutive photoreaction steps. A kinetic elucidation methodology useful for consecutive photoreactions was also proposed to determine all the kinetic parameters and reaction attributes defining AB 2 (2Φ) reactions. The quantum yields of photodegradation, determined for wavelengths in the visible region 400-480 nm, ranged from 0.005 to 0.00756 and 0.0012 to 8 10 -5 for the first and second photoreaction steps, respectively. They were found to increase with wavelength in defined sigmoid functions. For this monochromatic irradiation range, riboflavin proved to be a useful actinometer. Finally, a photodegradation scale based on pseudo-rate-constant values was also proposed for drugs. This scale (including 4 groups) is thought to contribute to rationalizing photodegradation testing and might prove useful in categorizing drugs' photodegradation reactivity. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

The pseudo-harmonics method: an application involving perturbations caused by control rod insertion in PWR reactors

International Nuclear Information System (INIS)

Claro, L.H.; Alvim, A.C.M.; Thome, Z.D.

1988-08-01

The objective of this work is to stydy the effect of intense perturbations, such as control rod insertion in the core of PWR reactors, through a perturbation approach consisting of a modified version of the pseudo-harmonics method. A typical one-dimensional PWR reactor model was used as a reference state, from which two perturbations were imposed, simulation gray and black control rod insertion. In the first case, eigenvalue convergence was achieved with the eighth order of approximation approximation and perturbed fluxes and eigenvalue estimates agreed very well with direct calculation results. The second case tested represents a very intense localized perturbation. Oscillation in keff were observed er of approximation increased and the method failed to converge. Results obtained indicate that the pseudo-harmonics method can be used to compute 2 group fluxes and fundamental eigenvalue of perturbated states resulting from gray control rod insertion in PWR reactors. The method is limited, however, by perturbation intensity, as other perturbation methods are. (author) [pt

Scintillation camera with second order resolution

International Nuclear Information System (INIS)

Muehllehner, G.

1976-01-01

A scintillation camera for use in radioisotope imaging to determine the concentration of radionuclides in a two-dimensional area is described in which means is provided for second order positional resolution. The phototubes, which normally provide only a single order of resolution, are modified to provide second order positional resolution of radiation within an object positioned for viewing by the scintillation camera. The phototubes are modified in that multiple anodes are provided to receive signals from the photocathode in a manner such that each anode is particularly responsive to photoemissions from a limited portion of the photocathode. Resolution of radioactive events appearing as an output of this scintillation camera is thereby improved

Scintillation camera with second order resolution

International Nuclear Information System (INIS)

1975-01-01

A scintillation camera is described for use in radioisotope imaging to determine the concentration of radionuclides in a two-dimensional area in which means is provided for second-order positional resolution. The phototubes which normally provide only a single order of resolution, are modified to provide second-order positional resolution of radiation within an object positioned for viewing by the scintillation camera. The phototubes are modified in that multiple anodes are provided to receive signals from the photocathode in a manner such that each anode is particularly responsive to photoemissions from a limited portion of the photocathode. Resolution of radioactive events appearing as an output of this scintillation camera is thereby improved

Simulation of cloud/radiation interaction using a second-order turbulence radiative-convective model

International Nuclear Information System (INIS)

Kao, C.Y.; Smith, W.S.

1994-01-01

Extended sheets of low-level stratus and stratocumulus clouds are a persistent feature over the eastern parts of the major ocean basins associated with the quasi-permanent subtropical high-pressure systems. These clouds exert a strong influence on climate through their high albedo, compared with the underlying surface, and their low altitude. The former leads to a reduction of the net shortwave flux entering the atmosphere, and the latter leads to an infrared loss in a way essentially the same as the cloud-free conditions. This paper is a modeling study with the current understanding of the important physical processes associated with a cloud-capped boundary layer. The numerical model is a high-resolution one-dimensional version of the second-order turbulence convective/radiative model developed at the Los Alamos National Laboratory. Future work includes sensitivity tests to ascertain the model validity as well as to systematically include all the possible ambient atmospheric and surface conditions. Detailed budget analyses are also useful in categorizing the cloud-capped boundary layers into a few classes

Hybrid approximations via second order combined dynamic derivatives on time scales

Directory of Open Access Journals (Sweden)

Qin Sheng

2007-09-01

Full Text Available This article focuses on the approximation of conventional second order derivative via the combined (diamond-$\\alpha$ dynamic derivative on time scales with necessary smoothness conditions embedded. We will show the constraints under which the second order dynamic derivative provides a consistent approximation to the conventional second derivative; the cases where the dynamic derivative approximates the derivative only via a proper modification of the existing formula; and the situations in which the dynamic derivative can never approximate consistently even with the help of available structure correction methods. Constructive error analysis will be given via asymptotic expansions for practical hybrid modeling and computational applications.

First-order system least-squares for second-order elliptic problems with discontinuous coefficients: Further results

Energy Technology Data Exchange (ETDEWEB)

Bloechle, B.; Manteuffel, T.; McCormick, S.; Starke, G.

1996-12-31

Many physical phenomena are modeled as scalar second-order elliptic boundary value problems with discontinuous coefficients. The first-order system least-squares (FOSLS) methodology is an alternative to standard mixed finite element methods for such problems. The occurrence of singularities at interface corners and cross-points requires that care be taken when implementing the least-squares finite element method in the FOSLS context. We introduce two methods of handling the challenges resulting from singularities. The first method is based on a weighted least-squares functional and results in non-conforming finite elements. The second method is based on the use of singular basis functions and results in conforming finite elements. We also share numerical results comparing the two approaches.

Theory of pseudo-differential operators over C*-Algebras

International Nuclear Information System (INIS)

Mohammad, N.

1987-06-01

In this article the behaviour of adjoints and composition of pseudo-differential operators in the framework of a C*-algebra is studied. It results that the class of pseudo-differential operators of order zero is a C*-algebra. 8 refs

Compressive sensing of electrocardiogram signals by promoting sparsity on the second-order difference and by using dictionary learning.

Science.gov (United States)

Pant, Jeevan K; Krishnan, Sridhar

2014-04-01

A new algorithm for the reconstruction of electrocardiogram (ECG) signals and a dictionary learning algorithm for the enhancement of its reconstruction performance for a class of signals are proposed. The signal reconstruction algorithm is based on minimizing the lp pseudo-norm of the second-order difference, called as the lp(2d) pseudo-norm, of the signal. The optimization involved is carried out using a sequential conjugate-gradient algorithm. The dictionary learning algorithm uses an iterative procedure wherein a signal reconstruction and a dictionary update steps are repeated until a convergence criterion is satisfied. The signal reconstruction step is implemented by using the proposed signal reconstruction algorithm and the dictionary update step is implemented by using the linear least-squares method. Extensive simulation results demonstrate that the proposed algorithm yields improved reconstruction performance for temporally correlated ECG signals relative to the state-of-the-art lp(1d)-regularized least-squares and Bayesian learning based algorithms. Also for a known class of signals, the reconstruction performance of the proposed algorithm can be improved by applying it in conjunction with a dictionary obtained using the proposed dictionary learning algorithm.

Stability and Convergence Analysis of Second-Order Schemes for a Diffuse Interface Model with Peng-Robinson Equation of State

KAUST Repository

Peng, Qiujin; Qiao, Zhonghua; Sun, Shuyu

2017-01-01

In this paper, we present two second-order numerical schemes to solve the fourth order parabolic equation derived from a diffuse interface model with Peng-Robinson Equation of state (EOS) for pure substance. The mass conservation, energy decay property, unique solvability and L-infinity convergence of these two schemes are proved. Numerical results demonstrate the good approximation of the fourth order equation and confirm reliability of these two schemes.

Stability and Convergence Analysis of Second-Order Schemes for a Diffuse Interface Model with Peng-Robinson Equation of State

KAUST Repository

Peng, Qiujin

2017-09-18

In this paper, we present two second-order numerical schemes to solve the fourth order parabolic equation derived from a diffuse interface model with Peng-Robinson Equation of state (EOS) for pure substance. The mass conservation, energy decay property, unique solvability and L-infinity convergence of these two schemes are proved. Numerical results demonstrate the good approximation of the fourth order equation and confirm reliability of these two schemes.

Postoperative ocular higher-order aberrations and contrast sensitivity: femtosecond lenticule extraction versus pseudo small-incision lenticule extraction.

Science.gov (United States)

Tan, Deborah K L; Tay, Wan Ting; Chan, Cordelia; Tan, Donald T H; Mehta, Jodhbir S

2015-03-01

To evaluate and compare changes in contrast sensitivity and ocular higher-order aberrations (HOAs) after femtosecond lenticule extraction (FLEx) and pseudo small-incision lenticule extraction (SMILE). Singapore National Eye Centre, Singapore. Retrospective case series. Patients had femtosecond lenticule extraction (Group 1) or pseudo small-incision lenticule extraction (Group 2) between March 2010 and December 2011. The main outcome measures were manifest refraction, HOAs, and contrast sensitivity 1, 3, 6, and 12 months postoperatively. Fifty-two consecutive patients (102 eyes) were recruited, 21 patients (42 eyes) in Group 1 and the 31 patients (60 eyes) in Group 2. The uncorrected and corrected distance visual acuities were significantly better in Group 2 than in Group 1 at 12 months (P = .032). There was no significant increase in 3rd- or 4th-order aberrations at 1 year and no significant difference between the 2 groups preoperatively or postoperatively. At 1 year, there was a significant increase in mesopic contrast sensitivity in Group 2 at 1.5 cycles per degree (cpd) (P = .008) that was not found in Group 1, and photopic contrast sensitivity at 6.0 cpd was higher in Group 2 (P = .027). These results indicate that refractive lenticule extraction is safe and effective with no significant induction of HOAs or deterioration in contrast sensitivity at 1 year. Induction of HOAs was not significantly different between both variants of refractive lenticule extraction. However, there was significant improvement in photopic contrast sensitivity after pseudo small-incision lenticule extraction, which persisted through 1 year. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Investigating local network interactions underlying first- and second-order processing.

Science.gov (United States)

Ellemberg, Dave; Allen, Harriet A; Hess, Robert F

2004-01-01

We compared the spatial lateral interactions for first-order cues to those for second-order cues, and investigated spatial interactions between these two types of cues. We measured the apparent modulation depth of a target Gabor at fixation, in the presence and the absence of horizontally flanking Gabors. The Gabors' gratings were either added to (first-order) or multiplied with (second-order) binary 2-D noise. Apparent "contrast" or modulation depth (i.e., the perceived difference between the high and low luminance regions for the first-order stimulus, or between the high and low contrast regions for the second-order stimulus) was measured with a modulation depth-matching paradigm. For each observer, the first- and second-order Gabors were equated for apparent modulation depth without the flankers. Our results indicate that at the smallest inter-element spacing, the perceived reduction in modulation depth is significantly smaller for the second-order than for the first-order stimuli. Further, lateral interactions operate over shorter distances and the spatial frequency and orientation tuning of the suppression effect are broader for second- than first-order stimuli. Finally, first- and second-order information interact in an asymmetrical fashion; second-order flankers do not reduce the apparent modulation depth of the first-order target, whilst first-order flankers reduce the apparent modulation depth of the second-order target.

Production of a pseudo-random square wave using a shift register with binary feedbacks; Generation d'un creneau pseudo-aleatoire par un registre a decalage a contre-reaction binaire

Energy Technology Data Exchange (ETDEWEB)

Stern, T E; Cazemajou, J; Macherez, B; Valat, J; Vignon, A

1964-07-01

We summarize here the theoretical basis for the production of square wave having the values '1' or '0', the switching times being 'pseudo-random'. More precisely, the square-wave may or may not change value at regular time intervals of length {delta}, with probability approximately. 5 for each alternative. The wave-form is obtained by means of a shift-register having modulo-2 feedback. If the interval {delta} and the feedback connections are well chosen, it is possible to produce a waveform whose autocorrelation function is very close to a Dirac delta function. The square-wave therefore behaves like a quantized white noise, which has very interesting properties in cross-correlation techniques. (authors) [French] On resume ici les bases theoriques permettant d'obtenir un creneau prenant les valeurs '1' ou '0', les instants de commutation etant pseudo-aleatoires. Plus exactement, le creneau a la possibilite de changer (ou de ne pas changer) d'etat a intervalles de temps reguliers, separes par intervalle elementaire {delta}, chacune des deux possibilites possedant une probabilite d'apparition tres voisine de 0,5. Le creneau est obtenu par un registre a decalage (shift register) a contre-reactions logiques modulo-2. Si l'intervalle {delta} et les contre-reactions sont judicieusement choisis, il est possible d'obtenir pour le creneau une fonction d'autocorrelation triangulaire tres voisine d'une impulsion de Dirac. Par suite le creneau se comporte comme un bruit blanc quantifie possedant de tres interessantes proprietes pour les techniques statistiques d'intercorrelation. (auteurs)

Second order logic, set theory and foundations of mathematics

NARCIS (Netherlands)

Väänänen, J.A.; Dybjer, P; Lindström, S; Palmgren, E; Sundholm, G

2012-01-01

The question, whether second order logic is a better foundation for mathematics than set theory, is addressed. The main difference between second order logic and set theory is that set theory builds up a transfinite cumulative hierarchy while second order logic stays within one application of the

Decomposition of a symmetric second-order tensor

Science.gov (United States)

Heras, José A.

2018-05-01

In the three-dimensional space there are different definitions for the dot and cross products of a vector with a second-order tensor. In this paper we show how these products can uniquely be defined for the case of symmetric tensors. We then decompose a symmetric second-order tensor into its ‘dot’ part, which involves the dot product, and the ‘cross’ part, which involves the cross product. For some physical applications, this decomposition can be interpreted as one in which the dot part identifies with the ‘parallel’ part of the tensor and the cross part identifies with the ‘perpendicular’ part. This decomposition of a symmetric second-order tensor may be suitable for undergraduate courses of vector calculus, mechanics and electrodynamics.

Modeling of Reaction Calorimeter

OpenAIRE

Farzad, Reza

2014-01-01

The purpose of this project was to model the reaction calorimeter in order to calculate the heat of absorption which is the most important parameter in this work. Reaction calorimeter is an apparatus which is used in measuring the heat of absorption of CO2 as well as the total pressure in vapor phase based on vapor-liquid equilibrium state. Mixture of monoethanolamine (MEA) and water was used as a solvent to absorb the CO2.Project was divided in to three parts in order to make the programming...

Photooxidative removal of the herbicide Acid Blue 9 in the presence of hydrogen peroxide: modeling of the reaction for evaluation of electrical energy per order (E EO).

Science.gov (United States)

Khataee, Ali R; Khataee, Hamid R

2008-09-01

The present work deals with photooxidative removal of the herbicide, Acid Blue 9 (AB9), in water in the presence of hydrogen peroxide (H2O2) under UV light illumination (30 W). The influence of the basic operational parameters such as amount of H2O2, irradiation time and initial concentration of AB9 on the photodegradation efficiency of the herbicide was investigated. The degradation rate of AB9 was not appreciably high when the photolysis was carried out in the absence of H2O2 and it was negligible in the absence of UV light. The photooxidative removal of the herbicide was found to follow pseudo-first-order kinetic, and hence the figure-of-merit electrical energy per order (E Eo) was considered appropriate for estimating the electrical energy efficiency. A mathematical relation between the apparent reaction rate constant and H2O2 used was applied for prediction of the electricity consumption in the photooxidative removal of AB9. The results indicated that this kinetic model, based on the initial rates of degradation, provided good prediction of the E Eo values for a variety of conditions. The results also indicated that the UV/H2O2 process was appropriate as the effective treatment method for removal of AB9 from the contaminated wastewater.

Investigation of second-order hyperpolarizability of some organic compounds

Science.gov (United States)

Tajalli, H.; Zirak, P.; Ahmadi, S.

2003-04-01

In this work, we have measured the second order hyperpolarizability of some organic materials with (EFISH) method and also calculated the second order hyperpolarizability of 13 organic compound with Mopac6 software and investigated the different factors that affect the amount of second order hyperpolarizability and ways to increase it.

Second-Order Footsteps Illusions

Directory of Open Access Journals (Sweden)

Akiyoshi Kitaoka

2015-12-01

Full Text Available In the “footsteps illusion”, light and dark squares travel at constant speed across black and white stripes. The squares appear to move faster and slower as their contrast against the stripes varies. We now demonstrate some second-order footsteps illusions, in which all edges are defined by colors or textures—even though luminance-based neural motion detectors are blind to such edges.

Entity models for trigger-reaction documents

NARCIS (Netherlands)

Khalid, M.A.; Marx, M.; Makkes, M.X.

2008-01-01

We define the notion of an entity model for a special kind of document popular on the web: an article followed by a list of reactions on that article, usually by many authors, usually inverse chronologically ordered. We call these documents trigger-reactions pairs. The entity model describes which

Second order pedagogy as an example of second order cybernetics

Directory of Open Access Journals (Sweden)

Anne B. Reinertsen

2012-07-01

Full Text Available This article is about seeing/creating/trying out an idea of pedagogy and pedagogical/ educational research in/as/with self-reflexive, circular and diffractive perspectives and about using second order cybernetics as thinking tool. It is a move away from traditional hypothesis driven activities and a move towards data driven pedagogies and research: Teachers, teacher researchers and researchers simultaneously producing and theorizing our practices and ourselves. Deleuzian becomings- eventually becomings with data - theory - theodata is pivotal. It is a move towards a Derridean bricolage. A different science of pedagogy operating as a circular science of self-reflexivity and diffraction in search of quality again and again and again: Theopractical becomings and inspiractionresearch.

Weak value amplification via second-order correlated technique

International Nuclear Information System (INIS)

Cui Ting; Huang Jing-Zheng; Zeng Gui-Hua; Liu Xiang

2016-01-01

We propose a new framework combining weak measurement and second-order correlated technique. The theoretical analysis shows that weak value amplification (WVA) experiment can also be implemented by a second-order correlated system. We then build two-dimensional second-order correlated function patterns for achieving higher amplification factor and discuss the signal-to-noise ratio influence. Several advantages can be obtained by our proposal. For instance, detectors with high resolution are not necessary. Moreover, detectors with low saturation intensity are available in WVA setup. Finally, type-one technical noise can be effectively suppressed. (paper)

Comparing pseudo-absences generation techniques in Boosted Regression Trees models for conservation purposes: A case study on amphibians in a protected area.

Directory of Open Access Journals (Sweden)

Francesco Cerasoli

Full Text Available Boosted Regression Trees (BRT is one of the modelling techniques most recently applied to biodiversity conservation and it can be implemented with presence-only data through the generation of artificial absences (pseudo-absences. In this paper, three pseudo-absences generation techniques are compared, namely the generation of pseudo-absences within target-group background (TGB, testing both the weighted (WTGB and unweighted (UTGB scheme, and the generation at random (RDM, evaluating their performance and applicability in distribution modelling and species conservation. The choice of the target group fell on amphibians, because of their rapid decline worldwide and the frequent lack of guidelines for conservation strategies and regional-scale planning, which instead could be provided through an appropriate implementation of SDMs. Bufo bufo, Salamandrina perspicillata and Triturus carnifex were considered as target species, in order to perform our analysis with species having different ecological and distributional characteristics. The study area is the "Gran Sasso-Monti della Laga" National Park, which hosts 15 Natura 2000 sites and represents one of the most important biodiversity hotspots in Europe. Our results show that the model calibration ameliorates when using the target-group based pseudo-absences compared to the random ones, especially when applying the WTGB. Contrarily, model discrimination did not significantly vary in a consistent way among the three approaches with respect to the tree target species. Both WTGB and RDM clearly isolate the highly contributing variables, supplying many relevant indications for species conservation actions. Moreover, the assessment of pairwise variable interactions and their three-dimensional visualization further increase the amount of useful information for protected areas' managers. Finally, we suggest the use of RDM as an admissible alternative when it is not possible to individuate a suitable set of

Stepwise training supports strategic second-order theory of mind in turn-taking games

NARCIS (Netherlands)

Verbrugge, Laurina; Meijering, Ben; Wierda, Stefan; van Rijn, Dirk; Taatgen, Niels

People model other people's mental states in order to understand and predict their behavior. Sometimes they model what others think about them as well: "He thinks that I intend to stop." Such second-order theory of mind is needed to navigate some social situations, for example, to make optimal

Second-order processing of four-stroke apparent motion.

Science.gov (United States)

Mather, G; Murdoch, L

1999-05-01

In four-stroke apparent motion displays, pattern elements oscillate between two adjacent positions and synchronously reverse in contrast, but appear to move unidirectionally. For example, if rightward shifts preserve contrast but leftward shifts reverse contrast, consistent rightward motion is seen. In conventional first-order displays, elements reverse in luminance contrast (e.g. light elements become dark, and vice-versa). The resulting perception can be explained by responses in elementary motion detectors turned to spatio-temporal orientation. Second-order motion displays contain texture-defined elements, and there is some evidence that they excite second-order motion detectors that extract spatio-temporal orientation following the application of a non-linear 'texture-grabbing' transform by the visual system. We generated a variety of second-order four-stroke displays, containing texture-contrast reversals instead of luminance contrast reversals, and used their effectiveness as a diagnostic test for the presence of various forms of non-linear transform in the second-order motion system. Displays containing only forward or only reversed phi motion sequences were also tested. Displays defined by variation in luminance, contrast, orientation, and size were effective. Displays defined by variation in motion, dynamism, and stereo were partially or wholly ineffective. Results obtained with contrast-reversing and four-stroke displays indicate that only relatively simple non-linear transforms (involving spatial filtering and rectification) are available during second-order energy-based motion analysis.

Second-order nonlinear optical metamaterials: ABC-type nanolaminates

International Nuclear Information System (INIS)

Alloatti, L.; Kieninger, C.; Lauermann, M.; Köhnle, K.; Froelich, A.; Wegener, M.; Frenzel, T.; Freude, W.; Leuthold, J.; Koos, C.

2015-01-01

We demonstrate a concept for second-order nonlinear metamaterials that can be obtained from non-metallic centrosymmetric constituents with inherently low optical absorption. The concept is based on iterative atomic-layer deposition of three different materials, A = Al 2 O 3 , B = TiO 2 , and C = HfO 2 . The centrosymmetry of the resulting ABC stack is broken since the ABC and the inverted CBA sequences are not equivalent—a necessary condition for non-zero second-order nonlinearity. In our experiments, we find that the bulk second-order nonlinear susceptibility depends on the density of interfaces, leading to a nonlinear susceptibility of 0.26 pm/V at a wavelength of 800 nm. ABC-type nanolaminates can be deposited on virtually any substrate and offer a promising route towards engineering of second-order optical nonlinearities at both infrared and visible wavelengths

Kubo Formulas for Second-Order Hydrodynamic Coefficients

International Nuclear Information System (INIS)

Moore, Guy D.; Sohrabi, Kiyoumars A.

2011-01-01

At second order in gradients, conformal relativistic hydrodynamics depends on the viscosity η and on five additional ''second-order'' hydrodynamical coefficients τ Π , κ, λ 1 , λ 2 , and λ 3 . We derive Kubo relations for these coefficients, relating them to equilibrium, fully retarded three-point correlation functions of the stress tensor. We show that the coefficient λ 3 can be evaluated directly by Euclidean means and does not in general vanish.

Integrating reaction and analysis: investigation of higher-order reactions by cryogenic trapping

Directory of Open Access Journals (Sweden)

Skrollan Stockinger

2013-09-01

Full Text Available A new approach for the investigation of a higher-order reaction by on-column reaction gas chromatography is presented. The reaction and the analytical separation are combined in a single experiment to investigate the Diels–Alder reaction of benzenediazonium-2-carboxylate as a benzyne precursor with various anthracene derivatives, i.e. anthracene, 9-bromoanthracene, 9-anthracenecarboxaldehyde and 9-anthracenemethanol. To overcome limitations of short reaction contact times at elevated temperatures a novel experimental setup was developed involving a cooling trap to achieve focusing and mixing of the reactants at a defined spot in a fused-silica capillary. This trap functions as a reactor within the separation column in the oven of a gas chromatograph. The reactants are sequentially injected to avoid undefined mixing in the injection port. An experimental protocol was developed with optimized injection intervals and cooling times to achieve sufficient conversions at short reaction times. Reaction products were rapidly identified by mass spectrometric detection. This new approach represents a practical procedure to investigate higher-order reactions at an analytical level and it simultaneously provides valuable information for the optimization of the reaction conditions.

Adsorption removal of acid black 1 from aqueous solution using ordered mesoporous carbon

Energy Technology Data Exchange (ETDEWEB)

Peng, Xiaoming, E-mail: pengxiaoming70@126.com [School of Civil Engineering, Southeast University, Nanjing 210096 (China); Hu, Xijun [Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,China (China); Fu, Dafang, E-mail: fdf@seu.edu.cn [School of Civil Engineering, Southeast University, Nanjing 210096 (China); Lam, Frank L.Y. [Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,China (China)

2014-03-01

Highlights: • Ordered mesoporous carbon was prepared using template. • Ordered mesoporous carbon was introduced of N-containing group by Chemical vapor deposition method. • Modified CMK-3 have better adsorption capacity and efficiency than virgin CMK-3 to removal AB1 dye. - Abstract: A novel ordered mesoporous carbon CMK-3 and synthetic CMK-3 containing nitrogen functional groups by ammonia-treated were applied for acid black 1(AB1) dye adsorption. The ammonia-treated(chemical vapor deposition method) before and after CMK-3 were characterized by using a Micrometitics ASAP 2020 surface area analyzer (ASAP 2020), Fourier transform infrared spectrophotometer (FT–IR), X-ray Photoelectron Spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and equilibrium studies. This result indicates that the prepared CMK-3 and modified CMK-3 were almost uniform, as rope-like domains and their uniform mesopore with diameter centered at 3.2 nm and 3.7 nm. The FIIR analysis depicted that the presence of a variety of new basic functional groups on the modified CMK-3 surface. Several effect variables of pH, dye concentration and temperature were studied. The pseudo second-order model showed the fitter well to agree with the kinetic data. The experimental data were analyzed by the Langmuir and Freundlich models, with the latter found to closely the isotherm model. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The results show that CMK-3 using ammonia gas modified by thermal treatment system is an effective method to improvement capacity as it shows the highest adsorption capacity of AB1, as compared to the unmodified CMK-3 and the bamboo-based carbon, respectively.

A new simple model for composite fading channels: Second order statistics and channel capacity

KAUST Repository

Yilmaz, Ferkan

2010-09-01

In this paper, we introduce the most general composite fading distribution to model the envelope and the power of the received signal in such fading channels as millimeter wave (60 GHz or above) fading channels and free-space optical channels, which we term extended generalized-K (EGK) composite fading distribution. We obtain the second-order statistics of the received signal envelope characterized by the EGK composite fading distribution. Expressions for probability density function, cumulative distribution function, level crossing rate and average fade duration, moments, amount of fading and average capacity are derived. Numerical and computer simulation examples validate the accuracy of the presented mathematical analysis. © 2010 IEEE.

A Pseudo-Bayesian Model for Stock Returns In Financial Crises

Directory of Open Access Journals (Sweden)

Eric S. Fung

2011-12-01

Full Text Available Recently, there has been a considerable interest in the Bayesian approach for explaining investors' behaviorial biases by incorporating conservative and representative heuristics when making financial decisions, (see, for example, Barberis, Shleifer and Vishny (1998. To establish a quantitative link between some important market anomalies and investors' behaviorial biases, Lam, Liu, and Wong (2010 introduced a pseudo-Bayesian approach for developing properties of stock returns, where weights induced by investors' conservative and representative heuristics are assigned to observations of the earning shocks and stock prices. In response to the recent global financial crisis, we introduce a new pseudo-Bayesian model to incorporate the impact of a financial crisis. Properties of stock returns during the financial crisis and recovery from the crisis are established. The proposed model can be applied to investigate some important market anomalies including short-term underreaction, long-term overreaction, and excess volatility during financial crisis. We also explain in some detail the linkage between these market anomalies and investors' behavioral biases during financial crisis.

Application of a non-equilibrium reaction model for describing horizontal well performance in foamy oil

Energy Technology Data Exchange (ETDEWEB)

Luigi, A.; Saputelli, B.; Carlas, M.; Canache, P.; Lopez, E. [DPVS Exploracion y Produccion (Venezuela)

1998-12-31

This study was designed to determine the activation energy ranges and frequency factor ranges in chemical reactions in heavy oils of the Orinoco Belt in Venezuela, in order to account for the kinetics of physical changes that occur in the morphology of gas-oil dispersion. A non-equilibrium reaction model was used to model foamy oil behaviour observed at SDZ-182 horizontal well in the Zuata field. Results showed that activation energy for the first reaction ranged from 0 to 0.01 BTU/lb-mol and frequency factor from 0.001 to 1000 l/day. For the second reaction the activation energy was 50x10{sub 3} BTU/lb-mol and the frequency factor 2.75x10{sub 1}2 l/day. The second reaction was highly sensitive to the modifications in activation energy and frequency factor. However, both the activation energy and frequency factor were independent of variations for the first reaction. In the case of the activation energy, the results showed that the high sensitivity of this parameter reflected the impact that temperature has on the representation of foamy oil behaviour. 8 refs., 2 tabs., 6 figs.

Liquid-Crystalline Ionic Liquids as Ordered Reaction Media for the Diels-Alder Reaction.

Science.gov (United States)

Bruce, Duncan W; Gao, Yanan; Canongia Lopes, José Nuno; Shimizu, Karina; Slattery, John M

2016-11-02

Liquid-crystalline ionic liquids (LCILs) are ordered materials that have untapped potential to be used as reaction media for synthetic chemistry. This paper investigates the potential for the ordered structures of LCILs to influence the stereochemical outcome of the Diels-Alder reaction between cyclopentadiene and methyl acrylate. The ratio of endo- to exo-product from this reaction was monitored for a range of ionic liquids (ILs) and LCILs. Comparison of the endo:exo ratios in these reactions as a function of cation, anion and liquid crystallinity of the reaction media, allowed for the effects of liquid crystallinity to be distinguished from anion effects or cation alkyl chain length effects. These data strongly suggest that the proportion of exo-product increases as the reaction media is changed from an isotropic IL to a LCIL. A detailed molecular dynamics (MD) study suggests that this effect is related to different hydrogen bonding interactions between the reaction media and the exo- and endo-transition states in solvents with layered, smectic ordering compared to those that are isotropic. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Second-order impartiality and public sphere

Directory of Open Access Journals (Sweden)

Sládeček Michal

2016-01-01

Full Text Available In the first part of the text the distinction between first- and second-order impartiality, along with Brian Barry’s thorough elaboration of their characteristics and the differences between them, is examined. While the former impartiality is related to non-favoring fellow-persons in everyday occasions, the latter is manifested in the institutional structure of society and its political and public morality. In the second part of the article, the concept of public impartiality is introduced through analysis of two examples. In the first example, a Caledonian Club with its exclusive membership is considered as a form of association which is partial, but nevertheless morally acceptable. In the second example, the so-called Heinz dilemma has been reconsidered and the author points to some flaws in Barry’s interpretation, arguing that Heinz’s right of giving advantage to his wife’s life over property rights can be recognized through mitigating circum-stances, and this partiality can be appreciated in the public sphere. Thus, public impartiality imposes limits to the restrictiveness and rigidity of political impartiality implied in second-order morality. [Projekat Ministarstva nauke Republike Srbije, br. 179049

Kinetic and isotherm modeling of Cd (II) adsorption by L-cysteine functionalized multi-walled carbon nanotubes as adsorbent.

Science.gov (United States)

Taghavi, Mahmoud; Zazouli, Mohammad Ali; Yousefi, Zabihollah; Akbari-adergani, Behrouz

2015-11-01

In this study, multi-walled carbon nanotubes were functionalized by L-cysteine to show the kinetic and isotherm modeling of Cd (II) ions onto L-cysteine functionalized multi-walled carbon nanotubes. The adsorption behavior of Cd (II) ion was studied by varying parameters including dose of L-MWCNTs, contact time, and cadmium concentration. Equilibrium adsorption isotherms and kinetics were also investigated based on Cd (II) adsorption tests. The results showed that an increase in contact time and adsorbent dosage resulted in increase of the adsorption rate. The optimum condition of the Cd (II) removal process was found at pH=7.0, 15 mg/L L-MWCNTs dosage, 6 mg/L cadmium concentration, and contact time of 60 min. The removal percent was equal to 89.56 at optimum condition. Langmuir and Freundlich models were employed to analyze the experimental data. The data showed well fitting with the Langmuir model (R2=0.994) with q max of 43.47 mg/g. Analyzing the kinetic data by the pseudo-first-order and pseudo-second-order equations revealed that the adsorption of cadmium using L-MWSNTs following the pseudo-second-order kinetic model with correlation coefficients (R2) equals to 0.998, 0.992, and 0.998 for 3, 6, and 9 mg/L Cd (II) concentrations, respectively. The experimental data fitted very well with the pseudo-second-order. Overall, treatment of polluted solution to Cd (II) by adsorption process using L-MWCNT can be considered as an effective technology.

Effect of electrolyte nature on kinetics of remazol yellow G removal by electrocoagulation

Science.gov (United States)

Rajabi, M.; Bagheri-Roochi, M.; Asghari, A.

2011-10-01

The present study describes an electrocoagulation process for the removal of remazol yellow G from dye solutions using Iron as the anode and Steel as the cathode. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to analyze the kinetic data obtained at different concentrations in different conditions. The adsorption kinetics was well described by the pseudo-second-order kinetic model.

Mathematical modelling of light-induced electric reaction of Cucurbita pepo L. leaves

Directory of Open Access Journals (Sweden)

Jan Stolarek

2014-01-01

Full Text Available The bioelectRIc reactions of 14-16 day old plants of pumpkin (Cucurbita pepo L. and internodal cells of Nitellopsis obtusa to the action of visible and ultraviolet light (UV-C were studied. The possibility of analyzing the bioelectric reaction of pumpkin plants induced by visible light by means of mathematical modelling using a linear differential equation of the second order was considered. The solution of this equation (positive and negative functions can, in a sufficient way, reflect the participation of H+ and CI- ions in the generation of the photoelectric response in green plant cells.

Pseudo dynamic transitional modeling of building heating energy demand using artificial neural network

NARCIS (Netherlands)

Paudel, S.; Elmtiri, M.; Kling, W.L.; Corre, le O.; Lacarriere, B.

2014-01-01

This paper presents the building heating demand prediction model with occupancy profile and operational heating power level characteristics in short time horizon (a couple of days) using artificial neural network. In addition, novel pseudo dynamic transitional model is introduced, which consider

'Second' Ehrenfest equation for second order phase transition under hydrostatic pressure

Science.gov (United States)

Moin, Ph. B.

2018-02-01

It is shown that the fundamental conditions for the second-order phase transitions ? and ?, from which the two Ehrenfest equations follow (the 'usual' and the 'second' ones), are realised only at zero hydrostatic pressure (?). At ? the volume jump ΔV at the transition is proportional to the pressure and to the jump of the compressibility ΔζV, whereas the entropy jump ΔS is proportional to the pressure and to the jump of the thermal expansion coefficient ΔαV. This means that at non-zero hydrostatic pressure the phase transition is of the first order and is described by the Clausius-Clapeyron equation. At small pressure this equation coincides with the 'second' Ehrenfest equation ?. At high P, the Clausius-Clapeyron equation describes qualitatively the caused by the crystal compression positive curvature of the ? dependence.

Second-Order Conditioning in "Drosophila"

Science.gov (United States)

Tabone, Christopher J.; de Belle, J. Steven

2011-01-01

Associative conditioning in "Drosophila melanogaster" has been well documented for several decades. However, most studies report only simple associations of conditioned stimuli (CS, e.g., odor) with unconditioned stimuli (US, e.g., electric shock) to measure learning or establish memory. Here we describe a straightforward second-order conditioning…

Examples of pseudo-bosons in quantum mechanics

International Nuclear Information System (INIS)

Bagarello, F.

2010-01-01

We discuss two physical examples of the so-called pseudo-bosons, recently introduced in connection with pseudo-hermitian quantum mechanics. In particular, we show that the so-called extended harmonic oscillator and the Swanson model satisfy all the assumptions of the pseudo-bosonic framework introduced by the author. We also prove that the biorthogonal bases they produce are not Riesz bases.

Role of pseudo-turbulent stresses in shocked particle clouds and construction of surrogate models for closure

Science.gov (United States)

Sen, O.; Gaul, N. J.; Davis, S.; Choi, K. K.; Jacobs, G.; Udaykumar, H. S.

2018-05-01

Macroscale models of shock-particle interactions require closure terms for unresolved solid-fluid momentum and energy transfer. These comprise the effects of mean as well as fluctuating fluid-phase velocity fields in the particle cloud. Mean drag and Reynolds stress equivalent terms (also known as pseudo-turbulent terms) appear in the macroscale equations. Closure laws for the pseudo-turbulent terms are constructed in this work from ensembles of high-fidelity mesoscale simulations. The computations are performed over a wide range of Mach numbers ( M) and particle volume fractions (φ ) and are used to explicitly compute the pseudo-turbulent stresses from the Favre average of the velocity fluctuations in the flow field. The computed stresses are then used as inputs to a Modified Bayesian Kriging method to generate surrogate models. The surrogates can be used as closure models for the pseudo-turbulent terms in macroscale computations of shock-particle interactions. It is found that the kinetic energy associated with the velocity fluctuations is comparable to that of the mean flow—especially for increasing M and φ . This work is a first attempt to quantify and evaluate the effect of velocity fluctuations for problems of shock-particle interactions.

Kinetics of biosorption of hazardous metals by green soil supplement

Science.gov (United States)

Bagla, Hemlata; Khilnani, Roshan

2016-04-01

of the biosorption in terms of the order of the rate constant were studied applying different kinetic models such as First order, Second order, Pseudo-first order, Pseudo-second order and the intra particle diffusion model. But among these models best fitting model was Lagergren pseudo second order model. The correlation coefficients of all the elements have R2 values close to 1 indicating the applicability of pseudo second order model to the present system. The applicability of this model suggested that biosorption of elements under study, on DCP was based on chemical interactions between metals and active sites of biosorbent. References 1. E. Tipping, Cation Binding by Humic Substances. Cambridge University Press, 2002. 2. S. Lagergren, Zur theorie der sogenannten adsorption geloster stoffe. Kungliga Svenska Vetenskapsakademiens, Handlingar vol. 24, no.4, pp. 1-39, 1898. 3. Y. S. Ho and G. McKay, "Pseudo-second order model for sorption processes," Process Biochem., vol. 34, no. 5, pp. 451-465, Jul. 1999. 4. N. S. Barot and H. K. Bagla, "Extraction of humic acid from biological matrix - dry cow dung powder," Green Chem. Lett. Rev., vol. 2, no. 4, pp. 217-221, 2009.

Rate kernel theory for pseudo-first-order kinetics of diffusion-influenced reactions and application to fluorescence quenching kinetics.

Science.gov (United States)

Yang, Mino

2007-06-07

Theoretical foundation of rate kernel equation approaches for diffusion-influenced chemical reactions is presented and applied to explain the kinetics of fluorescence quenching reactions. A many-body master equation is constructed by introducing stochastic terms, which characterize the rates of chemical reactions, into the many-body Smoluchowski equation. A Langevin-type of memory equation for the density fields of reactants evolving under the influence of time-independent perturbation is derived. This equation should be useful in predicting the time evolution of reactant concentrations approaching the steady state attained by the perturbation as well as the steady-state concentrations. The dynamics of fluctuation occurring in equilibrium state can be predicted by the memory equation by turning the perturbation off and consequently may be useful in obtaining the linear response to a time-dependent perturbation. It is found that unimolecular decay processes including the time-independent perturbation can be incorporated into bimolecular reaction kinetics as a Laplace transform variable. As a result, a theory for bimolecular reactions along with the unimolecular process turned off is sufficient to predict overall reaction kinetics including the effects of unimolecular reactions and perturbation. As the present formulation is applied to steady-state kinetics of fluorescence quenching reactions, the exact relation between fluorophore concentrations and the intensity of excitation light is derived.

Modelling Chemical Reasoning to Predict and Invent Reactions.

Science.gov (United States)

Segler, Marwin H S; Waller, Mark P

2017-05-02

The ability to reason beyond established knowledge allows organic chemists to solve synthetic problems and invent novel transformations. Herein, we propose a model that mimics chemical reasoning, and formalises reaction prediction as finding missing links in a knowledge graph. We have constructed a knowledge graph containing 14.4 million molecules and 8.2 million binary reactions, which represents the bulk of all chemical reactions ever published in the scientific literature. Our model outperforms a rule-based expert system in the reaction prediction task for 180 000 randomly selected binary reactions. The data-driven model generalises even beyond known reaction types, and is thus capable of effectively (re-)discovering novel transformations (even including transition metal-catalysed reactions). Our model enables computers to infer hypotheses about reactivity and reactions by only considering the intrinsic local structure of the graph and because each single reaction prediction is typically achieved in a sub-second time frame, the model can be used as a high-throughput generator of reaction hypotheses for reaction discovery. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pseudo color ghost coding imaging with pseudo thermal light

Science.gov (United States)

Duan, De-yang; Xia, Yun-jie

2018-04-01

We present a new pseudo color imaging scheme named pseudo color ghost coding imaging based on ghost imaging but with multiwavelength source modulated by a spatial light modulator. Compared with conventional pseudo color imaging where there is no nondegenerate wavelength spatial correlations resulting in extra monochromatic images, the degenerate wavelength and nondegenerate wavelength spatial correlations between the idle beam and signal beam can be obtained simultaneously. This scheme can obtain more colorful image with higher quality than that in conventional pseudo color coding techniques. More importantly, a significant advantage of the scheme compared to the conventional pseudo color coding imaging techniques is the image with different colors can be obtained without changing the light source and spatial filter.

First order and second order fermi acceleration of energetic charged particles by shock waves

International Nuclear Information System (INIS)

Webb, G.M.

1983-01-01

Steady state solutions of the cosmic ray transport equation describing first order Fermi acceleration of energetic charged particles at a plane shock (without losses) and second order Fermi acceleration in the downstream region of the shock are derived. The solutions for the isotropic part of the phase space distribution function are expressible as eigenfunction expansions, being superpositions of series of power law momentum spectra, with the power law indices being the roots of an eigenvalue equation. The above exact analytic solutions are for the case where the spatial diffusion coefficient kappa is independent of momentum. The solutions in general depend on the shock compression ratio, the modulation parameters V 1 L/kappa 1 , V 2 L/kappa 2 (V is the plasma velocity, kappa is the energetic particle diffusion coefficient, and L a characteristic length over which second order Fermi acceleration is effective) in the upstream and downstream regions of the shock, respectively, and also on a further dimensionless parameter, zeta, characterizing second order Fermi acceleration. In the limit as zeta→0 (no second order Fermi acceleration) the power law momentum spectrum characteristic of first order Fermi acceleration (depending only on the shock compression ratio) obtained previously is recovered. Perturbation solutions for the case where second order Fermi effects are small, and for realistic diffusion coefficients (kappainfinityp/sup a/, a>0, p = particle momentum), applicable at high momenta, are also obtained

Skyrme interaction to second order in nuclear matter

Science.gov (United States)

Kaiser, N.

2015-09-01

Based on the phenomenological Skyrme interaction various density-dependent nuclear matter quantities are calculated up to second order in many-body perturbation theory. The spin-orbit term as well as two tensor terms contribute at second order to the energy per particle. The simultaneous calculation of the isotropic Fermi-liquid parameters provides a rigorous check through the validity of the Landau relations. It is found that published results for these second order contributions are incorrect in most cases. In particular, interference terms between s-wave and p-wave components of the interaction can contribute only to (isospin or spin) asymmetry energies. Even with nine adjustable parameters, one does not obtain a good description of the empirical nuclear matter saturation curve in the low density region 0\\lt ρ \\lt 2{ρ }0. The reason for this feature is the too strong density-dependence {ρ }8/3 of several second-order contributions. The inclusion of the density-dependent term \\frac{1}{6}{t}3{ρ }1/6 is therefore indispensable for a realistic description of nuclear matter in the Skyrme framework.

On holographic entanglement entropy with second order excitations

Science.gov (United States)

He, Song; Sun, Jia-Rui; Zhang, Hai-Qing

2018-03-01

We study the low-energy corrections to the holographic entanglement entropy (HEE) in the boundary CFT by perturbing the bulk geometry up to second order excitations. Focusing on the case that the boundary subsystem is a strip, we show that the area of the bulk minimal surface can be expanded in terms of the conserved charges, such as mass, angular momentum and electric charge of the AdS black brane. We also calculate the variation of the energy in the subsystem and verify the validity of the first law-like relation of thermodynamics at second order. Moreover, the HEE is naturally bounded at second order perturbations if the cosmic censorship conjecture for the dual black hole still holds.

Comparison of Second-Order Loads on a Tension-Leg Platform for Wind Turbines: Preprint

Energy Technology Data Exchange (ETDEWEB)

Gueydon, S.; Wuillaume, P.; Jonkman, J.; Robertson, A.; Platt, A.

2015-03-01

The first objective of this work is to compare the two floating offshore wind turbine simulation packages {DIFFRAC+aNySIM} and {WAMIT+FAST}. The focus is on second-order wave loads, and so first- and second-order wave loads are applied to a structure sequentially for a detailed comparison and a more precise analysis of the effects of the second-order loads. aNySIM does not have the capability to model flexible bodies, and so the simulations performed in this tool are done assuming a rigid body. FAST also assumes that the platform is rigid, but can account for the flexibility of the tower. The second objective is to study the effects of the second-order loads on the response of a TLP floating wind turbine. The flexibility of the tower must be considered for this investigation, and therefore only FAST is used.

First- and second-order charged particle optics

International Nuclear Information System (INIS)

Brown, K.L.; Servranckx, R.V.

1984-07-01

Since the invention of the alternating gradient principle there has been a rapid evolution of the mathematics and physics techniques applicable to charged particle optics. In this publication we derive a differential equation and a matrix algebra formalism valid to second-order to present the basic principles governing the design of charged particle beam transport systems. A notation first introduced by John Streib is used to convey the essential principles dictating the design of such beam transport systems. For example the momentum dispersion, the momentum resolution, and all second-order aberrations are expressed as simple integrals of the first-order trajectories (matrix elements) and of the magnetic field parameters (multipole components) characterizing the system. 16 references, 30 figures

Principle component analysis (PCA) and second-order global hard-modelling for the complete resolution of transition metal ions complex formation with 1,10-phenantroline

International Nuclear Information System (INIS)

Shariati-Rad, Masoud; Hasani, Masoumeh

2009-01-01

Second-order global hard-modelling was applied to resolve the complex formation between Co 2+ , Ni 2+ , and Cd 2+ cations and 1,10-phenantroline. The highly correlated spectral and concentration profiles of the species in these systems and low concentration of some species in the individual collected data matrices prevent the well-resolution of the profiles. Therefore, a collection of six equilibrium data matrices including series of absorption spectra taken with pH changes at different reactant ratios were analyzed. Firstly, a precise principle component analysis (PCA) of different augmented arrangements of the individual data matrices was used to distinguish the number of species involved in the equilibria. Based on the results of PCA, the equilibria included in the data were specified and second-order global hard-modelling of the appropriate arrangement of six collected equilibrium data matrices resulted in well-resolved profiles and equilibrium constants. The protonation constant of the ligand (1,10-phenantroline) and spectral profiles of its protonated and unprotonated forms are the additional information obtained by global analysis. For comparison, multivariate curve resolution-alternating least squares (MCR-ALS) was applied to the same data. The results showed that second-order global hard-modelling is more convenient compared with MCR-ALS especially for systems with completely known model. It can completely resolve the system and the concentration profiles which are closer to correct ones. Moreover, parameters showing the goodness of fit are better with second-order global hard-modelling.

Principle component analysis (PCA) and second-order global hard-modelling for the complete resolution of transition metal ions complex formation with 1,10-phenantroline

Energy Technology Data Exchange (ETDEWEB)

Shariati-Rad, Masoud [Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65174 (Iran, Islamic Republic of); Hasani, Masoumeh, E-mail: hasani@basu.ac.ir [Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65174 (Iran, Islamic Republic of)

2009-08-19

Second-order global hard-modelling was applied to resolve the complex formation between Co{sup 2+}, Ni{sup 2+}, and Cd{sup 2+} cations and 1,10-phenantroline. The highly correlated spectral and concentration profiles of the species in these systems and low concentration of some species in the individual collected data matrices prevent the well-resolution of the profiles. Therefore, a collection of six equilibrium data matrices including series of absorption spectra taken with pH changes at different reactant ratios were analyzed. Firstly, a precise principle component analysis (PCA) of different augmented arrangements of the individual data matrices was used to distinguish the number of species involved in the equilibria. Based on the results of PCA, the equilibria included in the data were specified and second-order global hard-modelling of the appropriate arrangement of six collected equilibrium data matrices resulted in well-resolved profiles and equilibrium constants. The protonation constant of the ligand (1,10-phenantroline) and spectral profiles of its protonated and unprotonated forms are the additional information obtained by global analysis. For comparison, multivariate curve resolution-alternating least squares (MCR-ALS) was applied to the same data. The results showed that second-order global hard-modelling is more convenient compared with MCR-ALS especially for systems with completely known model. It can completely resolve the system and the concentration profiles which are closer to correct ones. Moreover, parameters showing the goodness of fit are better with second-order global hard-modelling.

Second-Order Learning Methods for a Multilayer Perceptron

International Nuclear Information System (INIS)

Ivanov, V.V.; Purehvdorzh, B.; Puzynin, I.V.

1994-01-01

First- and second-order learning methods for feed-forward multilayer neural networks are studied. Newton-type and quasi-Newton algorithms are considered and compared with commonly used back-propagation algorithm. It is shown that, although second-order algorithms require enhanced computer facilities, they provide better convergence and simplicity in usage. 13 refs., 2 figs., 2 tabs

Comparison of third-order plasma wave echoes with ballistic second-order plasma wave echoes

International Nuclear Information System (INIS)

Leppert, H.D.; Schuelter, H.; Wiesemann, K.

1982-01-01

The apparent dispersion of third-order plasma wave echoes observed in a high frequency plasma is compared with that of simultaneously observed ballistic second-order echoes. Amplitude and wavelength of third-order echoes are found to be always smaller than those of second-order echoes, however, the dispersion curves of both types of echoes are very similar. These observations are in qualitative agreement with calculations of special ballistic third-order echoes. The ballistic nature of the observed third-order echoes may, therefore, be concluded from these measurements. (author)

Sorption of Th(IV) onto ZnO nanoparticles and diatomite-supported ZnO nanocomposite. Kinetics, mechanism and activation parameters

Energy Technology Data Exchange (ETDEWEB)

Yusan, Sabriye; Aslani, Mahmut A.A.; Aytas, Sule [Ege Univ., Izmir (Turkey). Inst. of Nuclear Sciences; Bampaiti, Anastasia; Noli, Fotini [Aristotle University of Thessaloniki (Greece). Dept. of Chemistry; Erenturk, Sema [Istanbul Technical Univ., Ayazaga Campus, Maslak-Istanbul (Turkey). Energy Inst.

2016-11-01

In this study, for the first time ZnO nanoparticles and diatomite-supported ZnO nanocomposite have been utilized as adsorbent for the removal of Th(IV) ions from aqueous solutions under different experimental conditions. The Langmuir, Freundlich, Temkin and Dubinin- Radushkevich (D-R) isotherms were used to analyze the equilibrium data. The sorption equilibrium data were fitted well to the Langmuir isotherm with maximum sorption capacities values was found to be 1.105 mmol/g and 0.320 mmol/g for ZnO nanoparticles and diatomite supported ZnO nanocomposite, respectively. Pseudo-first and pseudo-second order equations, Intraparticle diffusion and Bangham's models were considered to evaluate the rate parameters and sorption mechanism. Sorption kinetics were better reproduced by the pseudo-second order model (R{sup 2} > 0.999), with an activation energy (E{sub a}) of +99.74 kJ/mol and +62.95 kJ/mol for ZnO nanoparticles and diatomite-supported ZnO nanocomposite, respectively. In order to specify the type of sorption reaction, thermodynamic parameters were also determined. The evaluated ΔG* and ΔH* indicate the non-spontaneous and endothermic nature of the reactions. The results of this work suggest that both of the used materials are fast and effective adsorbents for removing Th(IV) from aqueous solutions and chemical sorption plays a role in controlling the sorption rate.

Removal of Dye (Blue 56 From Aqueous Solution via Adsorption onto Pistachio Shell: kinetic and isotherm study of removal process

Directory of Open Access Journals (Sweden)

A. Ravanpaykar

2012-03-01

Full Text Available In the present investigation, shells of pistachio are used as adsorbents and they have been successfully used for the removal of Blue 56, from water samples. The effect of various parameters such as: pH, amounts of adsorbents, size of adsorbent particles and contact time on removal processing were investigated. Inthisstudy Freundlichabsorptionisotherms and Langmuir were investigated. The experimental data were correlated reasonably well by the Freundlich adsorption isotherm and isotherm parameters were calculated. In order to investigate the efficiency of Blue 56 adsorption on the pistachio shell, pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion kinetic models were studied. Themodel that hadgoodcorrelationtoattractFreundlichwas chosenasthemodel. Its kineticsfollowsthepseudosecond order reaction.

Modelling of infrared multiphoton absorption and dissociation for design of reactors for isotope separation by lasers

International Nuclear Information System (INIS)

Takeuchi, Kazuo; Nakane, Ryohei; Inoue, Cihiro

1981-01-01

A series of experiments were performed on infrared laser beam absorption (multiphoton absorption) and subsequent dissociation (multiphoton dissociation) of CF 3 Cl to propose models for the design of reactors for isotope separation by lasers. A parallel beam geometry was utilized in batch irradiation experiments to make direct compilation of lumped-parameter data possible. Multiphoton absorption is found to be expressed by a power-law extension of the law of Lambert and by an addition of a new term for buffer gas effect to the law of Beer. For reaction analysis, a method to evaluate the effect of incomplete mixing on apparent reaction rates is first presented. Secondly, multiphoton dissociation of Cf 3 Cl is found to occur in pseudo-first order fashion and the specific reaction rates for different beam fluence are shown to be correlated to the absorbed energy. (author)

Linearized pseudo-Einstein equations on the Heisenberg group

Science.gov (United States)

Barletta, Elisabetta; Dragomir, Sorin; Jacobowitz, Howard

2017-02-01

We study the pseudo-Einstein equation R11bar = 0 on the Heisenberg group H1 = C × R. We consider first order perturbations θɛ =θ0 + ɛ θ and linearize the pseudo-Einstein equation about θ0 (the canonical Tanaka-Webster flat contact form on H1 thought of as a strictly pseudoconvex CR manifold). If θ =e2uθ0 the linearized pseudo-Einstein equation is Δb u - 4 | Lu|2 = 0 where Δb is the sublaplacian of (H1 ,θ0) and L bar is the Lewy operator. We solve the linearized pseudo-Einstein equation on a bounded domain Ω ⊂H1 by applying subelliptic theory i.e. existence and regularity results for weak subelliptic harmonic maps. We determine a solution u to the linearized pseudo-Einstein equation, possessing Heisenberg spherical symmetry, and such that u(x) → - ∞ as | x | → + ∞.

Effective potential of the three-dimensional Ising model: The pseudo-ɛ expansion study

Science.gov (United States)

Sokolov, A. I.; Kudlis, A.; Nikitina, M. A.

2017-08-01

The ratios R2k of renormalized coupling constants g2k that enter the effective potential and small-field equation of state acquire the universal values at criticality. They are calculated for the three-dimensional scalar λϕ4 field theory (3D Ising model) within the pseudo-ɛ expansion approach. Pseudo-ɛ expansions for the critical values of g6, g8, g10, R6 =g6 / g42, R8 =g8 / g43 and R10 =g10 / g44 originating from the five-loop renormalization group (RG) series are derived. Pseudo-ɛ expansions for the sextic coupling have rapidly diminishing coefficients, so addressing Padé approximants yields proper numerical results. Use of Padé-Borel-Leroy and conformal mapping resummation techniques further improves the accuracy leading to the values R6* = 1.6488 and R6* = 1.6490 which are in a brilliant agreement with the result of advanced lattice calculations. For the octic coupling the numerical structure of the pseudo-ɛ expansions is less favorable. Nevertheless, the conform-Borel resummation gives R8* = 0.868, the number being close to the lattice estimate R8* = 0.871 and compatible with the result of 3D RG analysis R8* = 0.857. Pseudo-ɛ expansions for R10* and g10* are also found to have much smaller coefficients than those of the original RG series. They remain, however, fast growing and big enough to prevent obtaining fair numerical estimates.

Micromechanics based framework with second-order damage tensors

Science.gov (United States)

Desmorat, R.; Desmorat, B.; Olive, M.; Kolev, B.

2018-05-01

The harmonic product of tensors---leading to the concept of harmonic factorization---has been defined in a previous work (Olive et al, 2017). In the practical case of 3D crack density measurements on thin or thick walled structures, this mathematical tool allows us to factorize the harmonic (irreducible) part of the fourth-order damage tensor as an harmonic square: an exact harmonic square in 2D, an harmonic square over the set of so-called mechanically accessible directions for measurements in the 3D case. The corresponding micro-mechanics framework based on second---instead of fourth---order damage tensors is derived. An illustrating example is provided showing how the proposed framework allows for the modeling of the so-called hydrostatic sensitivity up to high damage levels.

The known unknowns: neural representation of second-order uncertainty, and ambiguity

Science.gov (United States)

Bach, Dominik R.; Hulme, Oliver; Penny, William D.; Dolan, Raymond J.

2011-01-01

Predictions provided by action-outcome probabilities entail a degree of (first-order) uncertainty. However, these probabilities themselves can be imprecise and embody second-order uncertainty. Tracking second-order uncertainty is important for optimal decision making and reinforcement learning. Previous functional magnetic resonance imaging investigations of second-order uncertainty in humans have drawn on an economic concept of ambiguity, where action-outcome associations in a gamble are either known (unambiguous) or completely unknown (ambiguous). Here, we relaxed the constraints associated with a purely categorical concept of ambiguity and varied the second-order uncertainty of gambles continuously, quantified as entropy over second-order probabilities. We show that second-order uncertainty influences decisions in a pessimistic way by biasing second-order probabilities, and that second-order uncertainty is negatively correlated with posterior cingulate cortex activity. The category of ambiguous (compared to non-ambiguous) gambles also biased choice in a similar direction, but was associated with distinct activation of a posterior parietal cortical area; an activation that we show reflects a different computational mechanism. Our findings indicate that behavioural and neural responses to second-order uncertainty are distinct from those associated with ambiguity and may call for a reappraisal of previous data. PMID:21451019

On holographic entanglement entropy with second order excitations

Directory of Open Access Journals (Sweden)

Song He

2018-03-01

Full Text Available We study the low-energy corrections to the holographic entanglement entropy (HEE in the boundary CFT by perturbing the bulk geometry up to second order excitations. Focusing on the case that the boundary subsystem is a strip, we show that the area of the bulk minimal surface can be expanded in terms of the conserved charges, such as mass, angular momentum and electric charge of the AdS black brane. We also calculate the variation of the energy in the subsystem and verify the validity of the first law-like relation of thermodynamics at second order. Moreover, the HEE is naturally bounded at second order perturbations if the cosmic censorship conjecture for the dual black hole still holds.

GENERAL THEORY OF THE ROTATION OF THE NON-RIGID EARTH AT THE SECOND ORDER. I. THE RIGID MODEL IN ANDOYER VARIABLES

International Nuclear Information System (INIS)

Getino, J.; Miguel, D.; Escapa, A.

2010-01-01

This paper is the first part of an investigation where we will present an analytical general theory of the rotation of the non-rigid Earth at the second order, which considers the effects of the interaction of the rotation of the Earth with itself, also named as the spin-spin coupling. Here, and as a necessary step in the development of that theory, we derive complete, explicit, analytical formulae of the rigid Earth rotation that account for the second-order rotation-rotation interaction. These expressions are not provided in this form by any current rigid Earth model. Working within the Hamiltonian framework established by Kinoshita, we study the second-order effects arising from the interaction of the main term in the Earth geopotential expansion with itself, and with the complementary term arising when referring the rotational motion to the moving ecliptic. To this aim, we apply a canonical perturbation method to solve analytically the canonical equations at the second order, determining the expressions that provide the nutation-precession, the polar motion, and the length of day. In the case of the motion of the equatorial plane, nutation-precession, we compare our general approach with the particular study for this motion developed by Souchay et al., showing the existence of new terms whose numerical values are within the truncation level of 0.1 μas adopted by those authors. These terms emerge as a consequence of not assuming in this work the same restrictive simplifications taken by Souchay et al. The importance of these additional contributions is that, as the analytical formulae show, they depend on the Earth model considered, in such a way that the fluid core resonance could amplify them significatively when extending this theory to the non-rigid Earth models.

Conformal symmetry and non-relativistic second-order fluid dynamics

International Nuclear Information System (INIS)

Chao Jingyi; Schäfer, Thomas

2012-01-01

We study the constraints imposed by conformal symmetry on the equations of fluid dynamics at second order in the gradients of the hydrodynamic variables. At zeroth order, conformal symmetry implies a constraint on the equation of state, E 0 =2/3 P, where E 0 is the energy density and P is the pressure. At first order, conformal symmetry implies that the bulk viscosity must vanish. We show that at second order, conformal invariance requires that two-derivative terms in the stress tensor must be traceless, and that it determines the relaxation of dissipative stresses to the Navier–Stokes form. We verify these results by solving the Boltzmann equation at second order in the gradient expansion. We find that only a subset of the terms allowed by conformal symmetry appear. - Highlights: ► We derive conformal constraints for the stress tensor of a scale invariant fluid. ► We determine the relaxation time in kinetic theory. ► We compute the rate of entropy production in second-order fluid dynamics.

Sensitivity study of cloud/radiation interaction using a second order turbulence radiative-convective model

International Nuclear Information System (INIS)

Kao, C.Y.J.; Smith, W.S.

1993-01-01

A high resolution one-dimensional version of a second order turbulence convective/radiative model, developed at the Los Alamos National Laboratory, was used to conduct a sensitivity study of a stratocumulus cloud deck, based on data taken at San Nicolas Island during the intensive field observation marine stratocumulus phase of the First International Satellite Cloud Climatology Program (ISCCP) Regional Experiment (FIRE IFO), conducted during July, 1987. Initial profiles for liquid water potential temperature, and total water mixing ratio were abstracted from the FIRE data. The dependence of the diurnal behavior in liquid water content, cloud top height, and cloud base height were examined for variations in subsidence rate, sea surface temperature, and initial inversion strength. The modelled diurnal variation in the column integrated liquid water agrees quite well with the observed data, for the case of low subsidence. The modelled diurnal behavior for the height of the cloud top and base show qualitative agreement with the FIRE data, although the overall height of the cloud layer is about 200 meters too high

Paleo Data Assimilation of Pseudo-Tree-Ring-Width Chronologies in a Climate Model

Science.gov (United States)

Fallah Hassanabadi, B.; Acevedo, W.; Reich, S.; Cubasch, U.

2016-12-01

Using the Time-Averaged Ensemble Kalman Filter (EnKF) and a forward model, we assimilate the pseudo Tree-Ring-Width (TRW) chronologies into an Atmospheric Global Circulation model. This study investigates several aspects of Paleo-Data Assimilation (PDA) within a perfect-model set-up: (i) we test the performance of several forward operators in the framework of a PDA-based climate reconstruction, (ii) compare the PDA-based simulations' skill against the free ensemble runs and (iii) inverstigate the skill of the "online" (with cycling) DA and the "off-line" (no-cycling) DA. In our experiments, the "online" (with cycling) PDA approach did not outperform the "off-line" (no-cycling) one, despite its considerable additional implementation complexity. On the other hand, it was observed that the error reduction achieved by assimilating a particular pseudo-TRW chronology is modulated by the strength of the yearly internal variability of the model at the chronology site. This result might help the dendrochronology community to optimize their sampling efforts.

KINETIC MODELS STUDY OF HYDRODESULPHURIZATION VACUUM DISTILLATE REACTION

Directory of Open Access Journals (Sweden)

AbdulMunem A. Karim

2013-05-01

Full Text Available    This study deals with  kinetics of hydrodesulphurization (HDS reaction of vacuum gas oil (611-833 K which was distillated from Kirkuk crude oil and which was obtained by blending the fractions, light vacuum gas oil (611 - 650 K, medium vacuum gas oil (650-690 K, heavy vacuum gas oil (690-727 K and very heavy vacuum gas oil (727-833 K.   The vacuum gas oil was hydrotreated on a commercial cobalt-molybdenum alumina catalyst presulfied at specified conditions in a laboratory trickle bed reactor. The reaction temperature range (583-643 K,liquid hourly space velocity range (1.5-3.75 h-1 and hydrogen pressure was kept constant at 3.5 MPa with hydrogen to oil ratio about 250 lt/lt.           The conversion results for desulphurization reaction appeared to obey the second order reaction. According to this model, the rate constants for desulphurization reaction were determined. Finally, the apparent activation energy (Ea, enthalpy of activation ( H* and entropy ( S* were calculated based on the values of rate constant (k2 and were equal 80.3792 KJ/mole, 75.2974 KJ/mole and 197.493 J/mole, respectively.

Second-Order Assortative Mixing in Social Networks

DEFF Research Database (Denmark)

Zhou, Shi; Cox, Ingemar; Hansen, Lars Kai

2017-01-01

In a social network, the number of links of a node, or node degree, is often assumed as a proxy for the node’s importance or prominence within the network. It is known that social networks exhibit the (first-order) assortative mixing, i.e. if two nodes are connected, they tend to have similar node...... degrees, suggesting that people tend to mix with those of comparable prominence. In this paper, we report the second-order assortative mixing in social networks. If two nodes are connected, we measure the degree correlation between their most prominent neighbours, rather than between the two nodes...... themselves. We observe very strong second-order assortative mixing in social networks, often significantly stronger than the first-order assortative mixing. This suggests that if two people interact in a social network, then the importance of the most prominent person each knows is very likely to be the same...

SECOND-ORDER SOLUTIONS OF COSMOLOGICAL PERTURBATION IN THE MATTER-DOMINATED ERA

International Nuclear Information System (INIS)

Hwang, Jai-chan; Noh, Hyerim; Gong, Jinn-Ouk

2012-01-01

We present the growing mode solutions of cosmological perturbations to the second order in the matter-dominated era. We also present several gauge-invariant combinations of perturbation variables to the second order in the most general fluid context. Based on these solutions, we study the Newtonian correspondence of relativistic perturbations to the second order. In addition to the previously known exact relativistic/Newtonian correspondence of density and velocity perturbations to the second order in the comoving gauge, here we show that in the sub-horizon limit we have the correspondences for density, velocity, and potential perturbations in the zero-shear gauge and in the uniform-expansion gauge to the second order. Density perturbation in the uniform-curvature gauge also shows the correspondence to the second order in the sub-horizon scale. We also identify the relativistic gravitational potential that shows exact correspondence to the Newtonian one to the second order.

Simulation of pulverized coal fired boiler: reaction chamber

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, C.P.; Lansarin, M.A.; Secchi, A.R.; Mendes, T.F. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica. Grupo de Modelagem, Simulacao, Controle e Otimizacao de Processos)]. E-mail: {cperdomo, marla, arge, talita}@enq.ufrgs.br

2005-06-15

This work is part of a joint project to built a computational tool for power plant simulation, dealing specifically with the reaction chamber (place of the boiler where the fuel is burned). In order to describe the conversion of chemical energy to thermal energy, an one dimensional pseudo-homogeneous mathematical model, with variable physical properties, and based on mass and energy balances, was developed. The equations were implemented in the gPROMS simulator and the model parameters were estimated using the module gEST of this software, with experimental data from a large-scale coal-fired utility boiler and kinetic data from the open literature. The results showed that the model predicts the composition of the outlet combustion gas satisfactorily. (author)

A Combined First and Second Order Variational Approach for Image Reconstruction

KAUST Repository

Papafitsoros, K.

2013-05-10

In this paper we study a variational problem in the space of functions of bounded Hessian. Our model constitutes a straightforward higher-order extension of the well known ROF functional (total variation minimisation) to which we add a non-smooth second order regulariser. It combines convex functions of the total variation and the total variation of the first derivatives. In what follows, we prove existence and uniqueness of minimisers of the combined model and present the numerical solution of the corresponding discretised problem by employing the split Bregman method. The paper is furnished with applications of our model to image denoising, deblurring as well as image inpainting. The obtained numerical results are compared with results obtained from total generalised variation (TGV), infimal convolution and Euler\\'s elastica, three other state of the art higher-order models. The numerical discussion confirms that the proposed higher-order model competes with models of its kind in avoiding the creation of undesirable artifacts and blocky-like structures in the reconstructed images-a known disadvantage of the ROF model-while being simple and efficiently numerically solvable. ©Springer Science+Business Media New York 2013.

Inverse modelling of atmospheric tracers: non-Gaussian methods and second-order sensitivity analysis

Directory of Open Access Journals (Sweden)

M. Bocquet

2008-02-01

Full Text Available For a start, recent techniques devoted to the reconstruction of sources of an atmospheric tracer at continental scale are introduced. A first method is based on the principle of maximum entropy on the mean and is briefly reviewed here. A second approach, which has not been applied in this field yet, is based on an exact Bayesian approach, through a maximum a posteriori estimator. The methods share common grounds, and both perform equally well in practice. When specific prior hypotheses on the sources are taken into account such as positivity, or boundedness, both methods lead to purposefully devised cost-functions. These cost-functions are not necessarily quadratic because the underlying assumptions are not Gaussian. As a consequence, several mathematical tools developed in data assimilation on the basis of quadratic cost-functions in order to establish a posteriori analysis, need to be extended to this non-Gaussian framework. Concomitantly, the second-order sensitivity analysis needs to be adapted, as well as the computations of the averaging kernels of the source and the errors obtained in the reconstruction. All of these developments are applied to a real case of tracer dispersion: the European Tracer Experiment [ETEX]. Comparisons are made between a least squares cost function (similar to the so-called 4D-Var approach and a cost-function which is not based on Gaussian hypotheses. Besides, the information content of the observations which is used in the reconstruction is computed and studied on the application case. A connection with the degrees of freedom for signal is also established. As a by-product of these methodological developments, conclusions are drawn on the information content of the ETEX dataset as seen from the inverse modelling point of view.

The sorption of lead, cadmium, copper and zinc ions from aqueous solutions on a raw diatomite from Algeria.

Science.gov (United States)

Safa, Messaouda; Larouci, Mohammed; Meddah, Boumediene; Valemens, Pierre

2012-01-01

The adsorption of Cu(2+), Zn(2+), Cd(2+) and Pb(2+) ions from aqueous solution by Algerian raw diatomite was studied. The influences of different sorption parameters such as contact pH solution, contact time and initial metal ions concentration were studied to optimize the reaction conditions. The metals ions adsorption was strictly pH dependent. The maximum adsorption capacities towards Cu(2+), Zn(2+), Cd(2+) and Pb(2+) were 0.319, 0.311, 0.18 and 0.096 mmol g(-1), respectively. The kinetic data were modelled using the pseudo-first-order and pseudo-second-order kinetic equations. Among the kinetic models studied, the pseudo-second-order equation was the best applicable model to describe the sorption process. Equilibrium isotherm data were analysed using the Langmuir and the Freundlich isotherms; the results showed that the adsorption equilibrium was well described by both model isotherms. The negative value of free energy change ΔG indicates feasible and spontaneous adsorption of four metal ions on raw diatomite. According to these results, the high exchange capacities of different metal ions at high and low concentration levels, and given the low cost of the investigated adsorbent in this work, Algerian diatomite was considered to be an excellent adsorbent.

Interacting wave fronts and rarefaction waves in a second order model of nonlinear thermoviscous fluids : Interacting fronts and rarefaction waves

DEFF Research Database (Denmark)

Rasmussen, Anders Rønne; Sørensen, Mads Peter; Gaididei, Yuri Borisovich

2011-01-01

A wave equation including nonlinear terms up to the second order for a thermoviscous Newtonian fluid is proposed. In the lossless case this equation results from an expansion to third order of the Lagrangian for the fundamental non-dissipative fluid dynamical equations. Thus it preserves the Hami...... is proposed. The dynamics of the rarefaction wave is approximated by a collective coordinate approach in the energy balance equation. © 2010 Springer Science+Business Media B.V.......A wave equation including nonlinear terms up to the second order for a thermoviscous Newtonian fluid is proposed. In the lossless case this equation results from an expansion to third order of the Lagrangian for the fundamental non-dissipative fluid dynamical equations. Thus it preserves...... the Hamiltonian structure, in contrast to the Kuznetsov equation, a model often used in nonlinear acoustics. An exact traveling wave front solution is derived from a generalized traveling wave assumption for the velocity potential. Numerical studies of the evolution of a number of arbitrary initial conditions...

Practical enhancement factor model based on GM for multiple parallel reactions: Piperazine (PZ) CO2 capture

DEFF Research Database (Denmark)

Gaspar, Jozsef; Fosbøl, Philip Loldrup

2017-01-01

Reactive absorption is a key process for gas separation and purification and it is the main technology for CO2 capture. Thus, reliable and simple mathematical models for mass transfer rate calculation are essential. Models which apply to parallel interacting and non-interacting reactions, for all......, desorption and pinch conditions.In this work, we apply the GM model to multiple parallel reactions. We deduce the model for piperazine (PZ) CO2 capture and we validate it against wetted-wall column measurements using 2, 5 and 8 molal PZ for temperatures between 40 °C and 100 °C and CO2 loadings between 0.......23 and 0.41 mol CO2/2 mol PZ. We show that overall second order kinetics describes well the reaction between CO2 and PZ accounting for the carbamate and bicarbamate reactions. Here we prove the GM model for piperazine and MEA but we expect that this practical approach is applicable for various amines...

Lagrange-Noether method for solving second-order differential equations

Institute of Scientific and Technical Information of China (English)

Wu Hui-Bin; Wu Run-Heng

2009-01-01

The purpose of this paper is to provide a new method called the Lagrange-Noether method for solving second-order differential equations. The method is,firstly,to write the second-order differential equations completely or partially in the form of Lagrange equations,and secondly,to obtain the integrals of the equations by using the Noether theory of the Lagrange system. An example is given to illustrate the application of the result.

Cellular Scanning Strategy for Selective Laser Melting: Capturing Thermal Trends with a Low-Fidelity, Pseudo-Analytical Model

Directory of Open Access Journals (Sweden)

Sankhya Mohanty

2014-01-01

Full Text Available Simulations of additive manufacturing processes are known to be computationally expensive. The resulting large runtimes prohibit their application in secondary analysis requiring several complete simulations such as optimization studies, and sensitivity analysis. In this paper, a low-fidelity pseudo-analytical model has been introduced to enable such secondary analysis. The model has been able to mimic a finite element model and was able to capture the thermal trends associated with the process. The model has been validated and subsequently applied in a small optimization case study. The pseudo-analytical modelling technique is established as a fast tool for primary modelling investigations.

Pseudo-periodic maps and degeneration of Riemann surfaces

CERN Document Server

Matsumoto, Yukio

2011-01-01

The first part of the book studies pseudo-periodic maps of a closed surface of genus greater than or equal to two. This class of homeomorphisms was originally introduced by J. Nielsen in 1944 as an extension of periodic maps. In this book, the conjugacy classes of the (chiral) pseudo-periodic mapping classes are completely classified, and Nielsen’s incomplete classification is corrected. The second part applies the results of the first part to the topology of degeneration of Riemann surfaces. It is shown that the set of topological types of all the singular fibers appearing in one-parameter holomorphic families of Riemann surfaces is in a bijective correspondence with the set of conjugacy classes of the pseudo-periodic maps of negative twists. The correspondence is given by the topological monodromy.

Reaction path analysis of sodium-water reaction phenomena in support of chemical reaction model development

International Nuclear Information System (INIS)

Kikuchi, Shin; Ohshima, Hiroyuki; Hashimoto, Kenro

2011-01-01

Computational study of the sodium-water reaction at the gas (water) - liquid (sodium) interface has been carried out using ab initio (first-principle) method. A possible reaction channel has been identified for the stepwise OH bond dissociations of a single water molecule. The energetics including the binding energy of a water molecule to the sodium surface, the activation energies of the bond cleavages, and the reaction energies, have been evaluated, and the rate constants of the first and second OH bond-breakings have been compared. The results are used as the basis for constructing the chemical reaction model used in a multi-dimensional sodium-water reaction code, SERAPHIM, being developed by JAEA toward the safety assessment of the steam generator (SG) in a sodium-cooled fast reactor (SFR). (author)

Second-order analysis of structured inhomogeneous spatio-temporal point processes

DEFF Research Database (Denmark)

Møller, Jesper; Ghorbani, Mohammad

Statistical methodology for spatio-temporal point processes is in its infancy. We consider second-order analysis based on pair correlation functions and K-functions for first general inhomogeneous spatio-temporal point processes and second inhomogeneous spatio-temporal Cox processes. Assuming...... spatio-temporal separability of the intensity function, we clarify different meanings of second-order spatio-temporal separability. One is second-order spatio-temporal independence and relates e.g. to log-Gaussian Cox processes with an additive covariance structure of the underlying spatio......-temporal Gaussian process. Another concerns shot-noise Cox processes with a separable spatio-temporal covariance density. We propose diagnostic procedures for checking hypotheses of second-order spatio-temporal separability, which we apply on simulated and real data (the UK 2001 epidemic foot and mouth disease data)....

Second-order generalized perturbation theory for source-driven systems

International Nuclear Information System (INIS)

Greenspan, E.; Gilai, D.; Oblow, E.M.

1978-01-01

A second-order generalized perturbation theory (GPT) for the effect of multiple system variations on a general flux functional in source-driven systems is derived. The derivation is based on a functional Taylor series in which second-order derivatives are retained. The resulting formulation accounts for the nonlinear effect of a given variation accurate to third order in the flux and adjoint perturbations. It also accounts for the effect of interaction between any number of variations. The new formulation is compared with exact perturbation theory as well as with perturbation theory for altered systems. The usefulnes of the second-order GPT formulation is illustrated by applying it to optimization problems. Its applicability to areas of cross-section sensitivity analysis and system design and evaluation is also discussed

Calculated Third Order Rate Constants for Interpreting the Mechanisms of Hydrolyses of Chloroformates, Carboxylic Acid Halides, Sulfonyl Chlorides and Phosphorochloridates

Directory of Open Access Journals (Sweden)

T. William Bentley

2015-05-01

Full Text Available Hydrolyses of acid derivatives (e.g., carboxylic acid chlorides and fluorides, fluoro- and chloroformates, sulfonyl chlorides, phosphorochloridates, anhydrides exhibit pseudo-first order kinetics. Reaction mechanisms vary from those involving a cationic intermediate (SN1 to concerted SN2 processes, and further to third order reactions, in which one solvent molecule acts as the attacking nucleophile and a second molecule acts as a general base catalyst. A unified framework is discussed, in which there are two reaction channels—an SN1-SN2 spectrum and an SN2-SN3 spectrum. Third order rate constants (k3 are calculated for solvolytic reactions in a wide range of compositions of acetone-water mixtures, and are shown to be either approximately constant or correlated with the Grunwald-Winstein Y parameter. These data and kinetic solvent isotope effects, provide the experimental evidence for the SN2-SN3 spectrum (e.g., for chloro- and fluoroformates, chloroacetyl chloride, p-nitrobenzoyl p-toluenesulfonate, sulfonyl chlorides. Deviations from linearity lead to U- or V-shaped plots, which assist in the identification of the point at which the reaction channel changes from SN2-SN3 to SN1-SN2 (e.g., for benzoyl chloride.

Second order optical nonlinearity in silicon by symmetry breaking

Energy Technology Data Exchange (ETDEWEB)

Cazzanelli, Massimo, E-mail: massimo.cazzanelli@unitn.it [Laboratorio IdEA, Dipartimento di Fisica, Università di Trento, via Sommarive, 14 Povo (Trento) (Italy); Schilling, Joerg, E-mail: joerg.schilling@physik.uni-halle.de [Centre for Innovation Competence SiLi-nano, Martin-Luther-University Halle-Wittenberg, Karl-Freiherr-von-Fritsch Str. 3, 06120 Halle (Germany)

2016-03-15

Although silicon does not possess a dipolar bulk second order nonlinear susceptibility due to its centro-symmetric crystal structure, in recent years several attempts were undertaken to create such a property in silicon. This review presents the different sources of a second order susceptibility (χ{sup (2)}) in silicon and the connected second order nonlinear effects which were investigated up to now. After an introduction, a theoretical overview discusses the second order nonlinearity in general and distinguishes between the dipolar contribution—which is usually dominating in non-centrosymmetric structures—and the quadrupolar contribution, which even exists in centro-symmetric materials. Afterwards, the classic work on second harmonic generation from silicon surfaces in reflection measurements is reviewed. Due to the abrupt symmetry breaking at surfaces and interfaces locally a dipolar second order susceptibility appears, resulting in, e.g., second harmonic generation. Since the bulk contribution is usually small, the study of this second harmonic signal allows a sensitive observation of the surface/interface conditions. The impact of covering films, strain, electric fields, and defect states at the interfaces was already investigated in this way. With the advent of silicon photonics and the search for ever faster electrooptic modulators, the interest turned to the creation of a dipolar bulk χ{sup (2)} in silicon. These efforts have been focussing on several experiments applying an inhomogeneous strain to the silicon lattice to break its centro-symmetry. Recent results suggesting the impact of electric fields which are exerted from fixed charges in adjacent covering layers are also included. After a subsequent summary on “competing” concepts using not Si but Si-related materials, the paper will end with some final conclusions, suggesting possible future research direction in this dynamically developing field.

A natural sorbent, Luffa cylindrica for the removal of a model basic dye

International Nuclear Information System (INIS)

Altinisik, Aylin; Guer, Emel; Seki, Yoldas

2010-01-01

In this work, application of Luffa cylindrica in malachite green (MG) removal from aqueous solution was studied in a batch system. The effect of contact time, pH and temperature on removal of malachite green was also investigated. By the time pH was increased from 3 to 5, the amount of sorbed malachite green also increased. Beyond the pH value of 5, the amount of sorbed malachite green remains constant. The fits of equilibrium sorption data to Langmuir, Freundlich and Dubinin-Radushkevich equations were investigated. Langmuir isotherm exhibited best fit with the experimental data. Monolayer sorption capacity increased with the increasing of temperature. Sorption kinetic was evaluated by pseudo-first-order, pseudo-second-order, Elovich rate equations and intraparticle diffusion models. It was inferred that sorption follows pseudo-second-order kinetic model. Thermodynamic parameters for sorption process were also found out. Spontaneous and endothermic nature of sorption was obtained due to negative value of free energy (ΔG o ) and positive value of enthalpy (ΔH o ) changes. FTIR analyses were also conducted to confirm the sorption of malachite green onto L. cylindrica.

Probabilistic Sophistication, Second Order Stochastic Dominance, and Uncertainty Aversion

OpenAIRE

Simone Cerreia-Vioglio; Fabio Maccheroni; Massimo Marinacci; Luigi Montrucchio

2010-01-01

We study the interplay of probabilistic sophistication, second order stochastic dominance, and uncertainty aversion, three fundamental notions in choice under uncertainty. In particular, our main result, Theorem 2, characterizes uncertainty averse preferences that satisfy second order stochastic dominance, as well as uncertainty averse preferences that are probabilistically sophisticated.

Second-order polarization-mode dispersion in photonic crystal fibers

DEFF Research Database (Denmark)

Larsen, T; Bjarklev, Anders Overgaard; Peterson, A

2003-01-01

We report the first experimental measurements of second-order polarization-mode dispersion in two successive 900 meter pulls of a silica photonic crystal fiber.......We report the first experimental measurements of second-order polarization-mode dispersion in two successive 900 meter pulls of a silica photonic crystal fiber....

NMR determination of the order parameter in proton and deuteron glasses

International Nuclear Information System (INIS)

Blinc, R.; Dolinsek, J.; Zalar, B.

1989-01-01

The inhomogeneous broadening of the ND + deuteron, O-D--O deuteron and 87 Rb quadrapole perturbed NMR spectra in Rb 0.56 (ND 4 ) 0.44 D 2 PO 4 is used for a direct determination of the Edwards-Anderson pseudo-spin glass order parameter. The data provide strong support for a model where the basic difference between magnetic spin glasses and proton or deuteron glasses is the presence of an inherent random field resulting from substitutional disorder which linearly couples to the O-D--O pseudo spins. In these systems we do not deal with a transition from a paraelectric to a pseudo-spin glass phase but rather with a transition from an ergodic pseudo-spin glass phase with a single order parameter q to a non-ergodic pseudo-spin glass phase with an infinite number of order parameters. (author). 11 refs.; 6 figs

Numerical evidence for quadrupolar-octopolar order in RETM{sub 2}(Al,Zi){sub 20}

Energy Technology Data Exchange (ETDEWEB)

Attig, Jan [Institute for Theoretical Physics, University of Cologne (Germany); Tse, Darrell; Lee, Eric Kin-Ho; Paramekanti, Arun; Kim, Yong Baek [Department of Physics, University of Toronto, ON (Canada)

2016-07-01

Motivated by recent experiments on materials of the type RETM{sub 2}(Al,Zi){sub 20} (where RE is a rare earth and TM a transition metal element) we investigate a minimal model for the pseudo-spin degrees of freedom of the rare earth ions. The model is described by J1-J2 pseudo-spin interactions in three-dimensions where the XY part models quadrupolar order and the Ising part models octopolar order. We use various computational methods such as simulating annealing to find the zero temperature phase digram and investigate further by using single-spin flip Monte Carlo simulations for finite temperature. One notable finding is the existence of non-coplanar spiral ordering of pseudo-spins, which may explain some of the experimental data on the electronic ordering in RETM{sub 2}(Al,Zi){sub 20}.

Model Consistent Pseudo-Observations of Precipitation and Their Use for Bias Correcting Regional Climate Models

Directory of Open Access Journals (Sweden)

Peter Berg

2015-01-01

Full Text Available Lack of suitable observational data makes bias correction of high space and time resolution regional climate models (RCM problematic. We present a method to construct pseudo-observational precipitation data bymerging a large scale constrained RCMreanalysis downscaling simulation with coarse time and space resolution observations. The large scale constraint synchronizes the inner domain solution to the driving reanalysis model, such that the simulated weather is similar to observations on a monthly time scale. Monthly biases for each single month are corrected to the corresponding month of the observational data, and applied to the finer temporal resolution of the RCM. A low-pass filter is applied to the correction factors to retain the small spatial scale information of the RCM. The method is applied to a 12.5 km RCM simulation and proven successful in producing a reliable pseudo-observational data set. Furthermore, the constructed data set is applied as reference in a quantile mapping bias correction, and is proven skillful in retaining small scale information of the RCM, while still correcting the large scale spatial bias. The proposed method allows bias correction of high resolution model simulations without changing the fine scale spatial features, i.e., retaining the very information required by many impact models.

Understanding operational risk capital approximations: First and second orders

Directory of Open Access Journals (Sweden)

Gareth W. Peters

2013-07-01

Full Text Available We set the context for capital approximation within the framework of the Basel II / III regulatory capital accords. This is particularly topical as the Basel III accord is shortly due to take effect. In this regard, we provide a summary of the role of capital adequacy in the new accord, highlighting along the way the significant loss events that have been attributed to the Operational Risk class that was introduced in the Basel II and III accords. Then we provide a semi-tutorial discussion on the modelling aspects of capital estimation under a Loss Distributional Approach (LDA. Our emphasis is to focuss on the important loss processes with regard to those that contribute most to capital, the so called “high consequence, low frequency" loss processes. This leads us to provide a tutorial overview of heavy tailed loss process modelling in OpRisk under Basel III, with discussion on the implications of such tail assumptions for the severity model in an LDA structure. This provides practitioners with a clear understanding of the features that they may wish to consider when developing OpRisk severity models in practice. From this discussion on heavy tailed severity models, we then develop an understanding of the impact such models have on the right tail asymptotics of the compound loss process and we provide detailed presentation of what are known as first and second order tail approximations for the resulting heavy tailed loss process. From this we develop a tutorial on three key families of risk measures and their equivalent second order asymptotic approximations: Value-at-Risk (Basel III industry standard; Expected Shortfall (ES and the Spectral Risk Measure. These then form the capital approximations. We then provide a few example case studies to illustrate the accuracy of these asymptotic captial approximations, the rate of the convergence of the assymptotic result as a function of the LDA frequency and severity model parameters, the sensitivity

Method to render second order beam optics programs symplectic

International Nuclear Information System (INIS)

Douglas, D.; Servranckx, R.V.

1984-10-01

We present evidence that second order matrix-based beam optics programs violate the symplectic condition. A simple method to avoid this difficulty, based on a generating function approach to evaluating transfer maps, is described. A simple example illustrating the non-symplectricity of second order matrix methods, and the effectiveness of our solution to the problem, is provided. We conclude that it is in fact possible to bring second order matrix optics methods to a canonical form. The procedure for doing so has been implemented in the program DIMAT, and could be implemented in programs such as TRANSPORT and TURTLE, making them useful in multiturn applications. 15 refs

Second order approximation for optical polaron in the strong coupling case

International Nuclear Information System (INIS)

Bogolubov, N.N. Jr.

1993-11-01

Here we propose a method of construction second order approximation for ground state energy for class of model Hamiltonian with linear type interaction on Bose operators in strong coupling case. For the application of the above method we have considered polaron model and propose construction set of nonlinear differential equations for definition ground state energy in strong coupling case. We have considered also radial symmetry case. (author). 10 refs

Nuclear matter with pseudo-particle model: static bulk and surface properties

Energy Technology Data Exchange (ETDEWEB)

Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

1993-12-31

Direct calculations of cold and hot nuclear matter (bulk and surface properties) are carried out within the frame of a pseudo-particle model using a Gaussian decomposition of the distribution function. Comparisons with Hartree-Fock calculations, for a large class of effective interactions, show that such a model is reliable to reproduce accurately the equation of state of nuclear matter for large ranges of densities and temperatures. The number of Gaussian per nucleon and the Gaussian widths are critical parameters in that semi-classical model. (author) 13 refs.; 9 figs.; 2 tabs.

Nuclear matter with pseudo-particle model: static bulk and surface properties

International Nuclear Information System (INIS)

Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

1993-01-01

Direct calculations of cold and hot nuclear matter (bulk and surface properties) are carried out within the frame of a pseudo-particle model using a Gaussian decomposition of the distribution function. Comparisons with Hartree-Fock calculations, for a large class of effective interactions, show that such a model is reliable to reproduce accurately the equation of state of nuclear matter for large ranges of densities and temperatures. The number of Gaussian per nucleon and the Gaussian widths are critical parameters in that semi-classical model. (author) 13 refs.; 9 figs.; 2 tabs

Biphasic kinetics in the reaction between amino acids or glutathione and the chromium acetate cluster, [Cr3O(OAc)6]+.

Science.gov (United States)

Chaudhary, Shveta; Van Horn, J David

2006-11-07

Kinetics for the breakdown of the trinuclear chromium acetate cluster with a series of monoprotic and diprotic amino acid ligands and with glutathione in aqueous media have been investigated spectrophotometrically at pH 3.5-5.5 and in a temperature range of 45-60 degrees C. Under pseudo-first-order conditions, reactions with these ligands exhibited biphasic kinetic behavior that can be accounted for by a consecutive two-step reaction, A-->B-->C, where A is assumed to be a forced ion pair, B an intermediate and C is the product; experimental data fit to a biexponential equation for the transformation. Rates for k(short), k(long), and k(obs) were determined by manual extrapolation of absorbance data or curve-fitting routines; associated activation parameters for each step of the reaction were calculated using the Eyring equation. Rates for the first and second steps of the reaction are on the order of approximately 10(-4) and approximately 10(-5)s(-1), respectively. The large negative values of DeltaS++ and smaller DeltaH++ in the first step indicate an associative step, while high positive values of DeltaS(double dagger) in the second step indicate dissociation. To account for the results mechanistically, the results are interpreted to be a first step of ligand exchange with a pseudo-axial aqua ligand, followed by a dissociative step involving acetate or oxo ligand displacement. The dissociative step is the rate determining step, with k(obs) approximately k(long). The results demonstrate reaction pathways that are available to the Cr(III) metal centers that may be physiologically relevant in the ligand-rich environment of biological systems. Under general conditions Cr(III) clusters may be expected to be broken down, unless some unique biological environment stabilizes the cluster. The present study has application to the processes related to Cr(III) transport and excretion, to potential mechanisms of Cr(III) action in a biological setting, and to the

Effect of pH on lead removal from water using tree fern as the sorbent.

Science.gov (United States)

Ho, Yuh-Shan

2005-07-01

The sorption of lead from water onto an agricultural by-product, tree fern, was examined as a function of pH. The sorption processes were carried out using an agitated and baffled system. Pseudo-second-order kinetic analyses were performed to determine the rate constant of sorption, the equilibrium sorption capacity, and the initial sorption rate. Application of the pseudo-second-order kinetics model produced very high coefficients of determination. Results showed the efficiency of tree fern as a sorbent for lead. The optimum pH for lead removal was between 4 and 7, with pH 4.9 resulting in better lead removal. Ion exchange occurred in the initial reaction period. In addition, a relation between the change in the solution hydrogen ion concentration and equilibrium capacity was developed and is presented.

Kinetic Approach for the Adsorption of Organophosphorous Pesticides from Aqueous Solution Using “Waste” Jute Fiber Carbon

Directory of Open Access Journals (Sweden)

S. Senthilkumaar

2010-01-01

Full Text Available Chemically activated “Waste” Jute Fiber carbon has been effectively used for the removal of five organophosphorous pesticides (malathion, monocrotophos, methylparathion, phosphamidon and dimethoate from aqueous solutions. The prepared activated jute fiber carbon was characterized by using Elemental analyzer and proximate analysis methods. The adsorption equilibrium was examined at 28 ºC. Three different kinetic models, the pseudo first order, pseudo second order and Elovich kinetic models were selected to analyses the adsorption process. To compare the fitness of pseudo first order and pseudo second order, sum of the squares of the errors and correlation coefficient, r2 values were calculated. The Elovich model was used to confirm the chemisorptions.

Investigation and kinetic evaluation of the reactions of hydroxymethylfurfural with amino and thiol groups of amino acids.

Science.gov (United States)

Hamzalıoğlu, Aytül; Gökmen, Vural

2018-02-01

In this study, reactions of hydroxymethylfurfural (HMF) with selected amino acids (arginine, cysteine and lysine) were investigated in HMF-amino acid (high moisture) and Coffee-amino acid (low moisture) model systems at 5, 25 and 50°C. The results revealed that HMF reacted efficiently and effectively with amino acids in both high and low moisture model systems. High-resolution mass spectrometry (HRMS) analyses of the reaction mixtures confirmed the formations of Michael adduct and Schiff base of HMF with amino acids. Calculated pseudo-first order reaction rate constants were in the following order; k Cysteine >k Arginine >k Lysine for high moisture model systems. Comparing to these rate constants, the k Cysteine decreased whereas, k Arginine and k Lysine increased under the low moisture conditions of Coffee-amino acid model systems. The temperature dependence of the rate constants was found to obey the Arrhenius law in a temperature range of 5-50°C under both low and high moisture conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Range walk error correction and modeling on Pseudo-random photon counting system

Science.gov (United States)

Shen, Shanshan; Chen, Qian; He, Weiji

2017-08-01

Signal to noise ratio and depth accuracy are modeled for the pseudo-random ranging system with two random processes. The theoretical results, developed herein, capture the effects of code length and signal energy fluctuation are shown to agree with Monte Carlo simulation measurements. First, the SNR is developed as a function of the code length. Using Geiger-mode avalanche photodiodes (GMAPDs), longer code length is proven to reduce the noise effect and improve SNR. Second, the Cramer-Rao lower bound on range accuracy is derived to justify that longer code length can bring better range accuracy. Combined with the SNR model and CRLB model, it is manifested that the range accuracy can be improved by increasing the code length to reduce the noise-induced error. Third, the Cramer-Rao lower bound on range accuracy is shown to converge to the previously published theories and introduce the Gauss range walk model to range accuracy. Experimental tests also converge to the presented boundary model in this paper. It has been proven that depth error caused by the fluctuation of the number of detected photon counts in the laser echo pulse leads to the depth drift of Time Point Spread Function (TPSF). Finally, numerical fitting function is used to determine the relationship between the depth error and the photon counting ratio. Depth error due to different echo energy is calibrated so that the corrected depth accuracy is improved to 1cm.

A numerical study of the second-order wave excitation of ship springing by a higher-order boundary element method

Directory of Open Access Journals (Sweden)

Shao Yan-Lin

2014-12-01

Full Text Available This paper presents some of the efforts by the authors towards numerical prediction of springing of ships. A time-domain Higher Order Boundary Element Method (HOBEM based on cubic shape function is first presented to solve a complete second-order problem in terms of wave steepness and ship motions in a consistent manner. In order to avoid high order derivatives on the body surfaces, e.g. mj-terms, a new formulation of the Boundary Value Problem in a body-fixed coordinate system has been proposed instead of traditional formulation in inertial coordinate system. The local steady flow effects on the unsteady waves are taken into account. Double-body flow is used as the basis flow which is an appropriate approximation for ships with moderate forward speed. This numerical model was used to estimate the complete second order wave excitation of springing of a displacement ship at constant forward speeds.

A Pseudo-3D Model for Electromagnetic Acoustic Transducers (EMATs

Directory of Open Access Journals (Sweden)

Wuliang Yin

2018-03-01

Full Text Available Previous methods for modelling Rayleigh waves produced by a meander-line-coil electromagnetic acoustic transducer (EMAT consisted mostly of two-dimensional (2D simulations that focussed on the vertical plane of the material. This paper presents a pseudo-three-dimensional (3D model that extends the simulation space to both vertical and horizontal planes. For the vertical plane, we combines analytical and finite-difference time-domain (FDTD methods to model Rayleigh waves’ propagation within an aluminium plate and their scattering behaviours by cracks. For the horizontal surface plane, we employ an analytical method to investigate the radiation pattern of Rayleigh waves at various depths. The experimental results suggest that the models and the modelling techniques are valid.

Pseudo-Glassification Material for G-Demption

Energy Technology Data Exchange (ETDEWEB)

Casella, Andrew M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buck, Edgar C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gates, Robert O. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Riley, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-09-01

G-Demption, LLC has requested that PPNL provide design input for a “pseudo-glassification” process associated with their proposed technology for generating gamma irradiation stations from used nuclear fuel. The irradiation design currently consists of an aluminum enclosure designed to allow for proper encapsulation of and heat flow from a used fuel rod while minimally impacting the streaming of gamma rays from the fuel. In order to make their design more robust, G-Demption is investigating the benefits of backfilling this aluminum enclosure with a setting material once the used fuel rod is properly placed. This process has been initially referred to as “pseudo-glassification”, and strives not to impact heat transport or gamma streaming from the used fuel rod while providing increased fuel rod protection and fission gas retention. PNNL has compiled an internal material evaluation and discussion for the “pseudo-glassification” process in this report.

Conformal conservation laws for second-order scalar fields

International Nuclear Information System (INIS)

Blakeskee, J.S.; Logan, J.D.

1976-01-01

It is considered an action integral over space-time whose Lagrangian depends upon a scalar field an upon derivatives of the field function up to second order. From invariance identities obtained by the authors in an earlier work it is shown how a new proof of Noether's theorem for this second-order problem follows in the multiple integral case. Finally, conservation laws are written down in the case that the given action integral be invariant under the fifteen-parameter special conformal group

Higher-order Cauchy of the second kind and poly-Cauchy of the second kind mixed type polynomials

OpenAIRE

Kim, Dae San; Kim, Taekyun

2013-01-01

In this paper, we investigate some properties of higher-order Cauchy of the second kind and poly-Cauchy of the second mixed type polynomials with umbral calculus viewpoint. From our investigation, we derive many interesting identities of higher-order Cauchy of the second kind and poly-Cauchy of the second kind mixed type polynomials.

Pseudo-set framing.

Science.gov (United States)

Barasz, Kate; John, Leslie K; Keenan, Elizabeth A; Norton, Michael I

2017-10-01

Pseudo-set framing-arbitrarily grouping items or tasks together as part of an apparent "set"-motivates people to reach perceived completion points. Pseudo-set framing changes gambling choices (Study 1), effort (Studies 2 and 3), giving behavior (Field Data and Study 4), and purchase decisions (Study 5). These effects persist in the absence of any reward, when a cost must be incurred, and after participants are explicitly informed of the arbitrariness of the set. Drawing on Gestalt psychology, we develop a conceptual account that predicts what will-and will not-act as a pseudo-set, and defines the psychological process through which these pseudo-sets affect behavior: over and above typical reference points, pseudo-set framing alters perceptions of (in)completeness, making intermediate progress seem less complete. In turn, these feelings of incompleteness motivate people to persist until the pseudo-set has been fulfilled. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Optimality Conditions in Differentiable Vector Optimization via Second-Order Tangent Sets

International Nuclear Information System (INIS)

Jimenez, Bienvenido; Novo, Vicente

2004-01-01

We provide second-order necessary and sufficient conditions for a point to be an efficient element of a set with respect to a cone in a normed space, so that there is only a small gap between necessary and sufficient conditions. To this aim, we use the common second-order tangent set and the asymptotic second-order cone utilized by Penot. As an application we establish second-order necessary conditions for a point to be a solution of a vector optimization problem with an arbitrary feasible set and a twice Frechet differentiable objective function between two normed spaces. We also establish second-order sufficient conditions when the initial space is finite-dimensional so that there is no gap with necessary conditions. Lagrange multiplier rules are also given

A two-step ionospheric modeling algorithm considering the impact of GLONASS pseudo-range inter-channel biases

Science.gov (United States)

Zhang, Rui; Yao, Yi-bin; Hu, Yue-ming; Song, Wei-wei

2017-12-01

The Global Navigation Satellite System presents a plausible and cost-effective way of computing the total electron content (TEC). But TEC estimated value could be seriously affected by the differential code biases (DCB) of frequency-dependent satellites and receivers. Unlike GPS and other satellite systems, GLONASS adopts a frequency-division multiplexing access mode to distinguish different satellites. This strategy leads to different wavelengths and inter-frequency biases (IFBs) for both pseudo-range and carrier phase observations, whose impacts are rarely considered in ionospheric modeling. We obtained observations from four groups of co-stations to analyze the characteristics of the GLONASS receiver P1P2 pseudo-range IFB with a double-difference method. The results showed that the GLONASS P1P2 pseudo-range IFB remained stable for a period of time and could catch up to several meters, which cannot be absorbed by the receiver DCB during ionospheric modeling. Given the characteristics of the GLONASS P1P2 pseudo-range IFB, we proposed a two-step ionosphere modeling method with the priori IFB information. The experimental analysis showed that the new algorithm can effectively eliminate the adverse effects on ionospheric model and hardware delay parameters estimation in different space environments. During high solar activity period, compared to the traditional GPS + GLONASS modeling algorithm, the absolute average deviation of TEC decreased from 2.17 to 2.07 TECu (TEC unit); simultaneously, the average RMS of GPS satellite DCB decreased from 0.225 to 0.219 ns, and the average deviation of GLONASS satellite DCB decreased from 0.253 to 0.113 ns with a great improvement in over 55%.

Feature Scaling via Second-Order Cone Programming

Directory of Open Access Journals (Sweden)

Zhizheng Liang

2016-01-01

Full Text Available Feature scaling has attracted considerable attention during the past several decades because of its important role in feature selection. In this paper, a novel algorithm for learning scaling factors of features is proposed. It first assigns a nonnegative scaling factor to each feature of data and then adopts a generalized performance measure to learn the optimal scaling factors. It is of interest to note that the proposed model can be transformed into a convex optimization problem: second-order cone programming (SOCP. Thus the scaling factors of features in our method are globally optimal in some sense. Several experiments on simulated data, UCI data sets, and the gene data set are conducted to demonstrate that the proposed method is more effective than previous methods.

Biosorption kinetics of Cd (II), Cr (III) and Pb (II) in aqueous solutions by olive stone

OpenAIRE

M. Calero; F. Hernáinz; G. Blázquez; M. A. Martín-Lara; G. Tenorio

2009-01-01

A by-product from olive oil production, olive stone, was investigated for the removal of Cd (II), Cr (III) and Pb (II) from aqueous solutions. The kinetics of biosorption are studied, analyzing the effect of the initial concentration of metal and temperature. Pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models have been used to represent the kinetics of the process and obtain the main kinetic parameters. The results show that the pseudo-second order model is th...

Nontrivial Periodic Solutions for Nonlinear Second-Order Difference Equations

Directory of Open Access Journals (Sweden)

Tieshan He

2011-01-01

Full Text Available This paper is concerned with the existence of nontrivial periodic solutions and positive periodic solutions to a nonlinear second-order difference equation. Under some conditions concerning the first positive eigenvalue of the linear equation corresponding to the nonlinear second-order equation, we establish the existence results by using the topological degree and fixed point index theories.

Pseudo-random bit generator based on lag time series

Science.gov (United States)

García-Martínez, M.; Campos-Cantón, E.

2014-12-01

In this paper, we present a pseudo-random bit generator (PRBG) based on two lag time series of the logistic map using positive and negative values in the bifurcation parameter. In order to hidden the map used to build the pseudo-random series we have used a delay in the generation of time series. These new series when they are mapped xn against xn+1 present a cloud of points unrelated to the logistic map. Finally, the pseudo-random sequences have been tested with the suite of NIST giving satisfactory results for use in stream ciphers.

Emergence of Lévy Walks from Second-Order Stochastic Optimization

Science.gov (United States)

Kuśmierz, Łukasz; Toyoizumi, Taro

2017-12-01

In natural foraging, many organisms seem to perform two different types of motile search: directed search (taxis) and random search. The former is observed when the environment provides cues to guide motion towards a target. The latter involves no apparent memory or information processing and can be mathematically modeled by random walks. We show that both types of search can be generated by a common mechanism in which Lévy flights or Lévy walks emerge from a second-order gradient-based search with noisy observations. No explicit switching mechanism is required—instead, continuous transitions between the directed and random motions emerge depending on the Hessian matrix of the cost function. For a wide range of scenarios, the Lévy tail index is α =1 , consistent with previous observations in foraging organisms. These results suggest that adopting a second-order optimization method can be a useful strategy to combine efficient features of directed and random search.

On the Robustness of Hysteretic Second-Order Systems with PID : iISS approach

NARCIS (Netherlands)

Ouyang, Ruiyue; Jayawardhana, Bayu; Andrieu, Vincent

2012-01-01

In this paper, we study the robustness property of a second-order linear plant controlled by a proportional, integral and derivative (PID) controller with a hysteretic actuator. The hysteretic actuator is modeled by a Duhem model that exhibits clockwise (CW) input-output (I/O) dynamics (such as the

Pseudo-observations in survival analysis

DEFF Research Database (Denmark)

Andersen, Per Kragh; Perme, Maja Pohar

2010-01-01

-state models, e.g. the competing risks cumulative incidence function. Graphical and numerical methods for assessing goodness-of-fit for hazard regression models and for the Fine-Gray model in competing risks studies based on pseudo-observations are also reviewed. Sensitivity to covariate-dependent censoring...

The Efficient Removal of Heavy Metal Ions from Industry Effluents Using Waste Biomass as Low-Cost Adsorbent: Thermodynamic and Kinetic Models

Science.gov (United States)

Indhumathi, Ponnuswamy; Sathiyaraj, Subbaiyan; Koelmel, Jeremy P.; Shoba, Srinivasan U.; Jayabalakrishnan, Chinnasamy; Saravanabhavan, Munusamy

2018-05-01

The ability of green micro algae Chlorella vulgaris for biosorption of Cu(II) ions from an aqueous solution was studied. The biosorption process was affected by the solution pH, contact time, temperature and initial Cu(II) concentration. Experimental data were analyzed in terms of pseudo-first order, pseudo-second order and intra particle diffusion models. Results showed that the sorption process of Cu(II) ions followed pseudo-second order kinetics. The sorption data of Cu(II) ions are fitted to Langmuir, Freundlich, and Redlich-Peterson isotherms, and the Temkin isotherm. The thermodynamic study shows the Cu(II) biosorption was exothermic in nature. The Cu(II) ions were recovered effectively from Chlorella vulgaris biomass using 0.1 M H2SO4 with up to 90.3% recovery, allowing for recycling of the Cu. Green algae from freshwater bodies showed significant potential for Cu(II) removal and recovery from industrial wastewater.

A maximum pseudo-likelihood approach for estimating species trees under the coalescent model

Directory of Open Access Journals (Sweden)

Edwards Scott V

2010-10-01

Full Text Available Abstract Background Several phylogenetic approaches have been developed to estimate species trees from collections of gene trees. However, maximum likelihood approaches for estimating species trees under the coalescent model are limited. Although the likelihood of a species tree under the multispecies coalescent model has already been derived by Rannala and Yang, it can be shown that the maximum likelihood estimate (MLE of the species tree (topology, branch lengths, and population sizes from gene trees under this formula does not exist. In this paper, we develop a pseudo-likelihood function of the species tree to obtain maximum pseudo-likelihood estimates (MPE of species trees, with branch lengths of the species tree in coalescent units. Results We show that the MPE of the species tree is statistically consistent as the number M of genes goes to infinity. In addition, the probability that the MPE of the species tree matches the true species tree converges to 1 at rate O(M -1. The simulation results confirm that the maximum pseudo-likelihood approach is statistically consistent even when the species tree is in the anomaly zone. We applied our method, Maximum Pseudo-likelihood for Estimating Species Trees (MP-EST to a mammal dataset. The four major clades found in the MP-EST tree are consistent with those in the Bayesian concatenation tree. The bootstrap supports for the species tree estimated by the MP-EST method are more reasonable than the posterior probability supports given by the Bayesian concatenation method in reflecting the level of uncertainty in gene trees and controversies over the relationship of four major groups of placental mammals. Conclusions MP-EST can consistently estimate the topology and branch lengths (in coalescent units of the species tree. Although the pseudo-likelihood is derived from coalescent theory, and assumes no gene flow or horizontal gene transfer (HGT, the MP-EST method is robust to a small amount of HGT in the

Reanalysis of Rate Data for the Reaction CH3 + CH3 → C2H6 Using Revised Cross Sections and a Linearized Second-Order Master Equation.

Science.gov (United States)

Blitz, M A; Green, N J B; Shannon, R J; Pilling, M J; Seakins, P W; Western, C M; Robertson, S H

2015-07-16

Rate coefficients for the CH3 + CH3 reaction, over the temperature range 300-900 K, have been corrected for errors in the absorption coefficients used in the original publication ( Slagle et al., J. Phys. Chem. 1988 , 92 , 2455 - 2462 ). These corrections necessitated the development of a detailed model of the B̃(2)A1' (3s)-X̃(2)A2″ transition in CH3 and its validation against both low temperature and high temperature experimental absorption cross sections. A master equation (ME) model was developed, using a local linearization of the second-order decay, which allows the use of standard matrix diagonalization methods for the determination of the rate coefficients for CH3 + CH3. The ME model utilized inverse Laplace transformation to link the microcanonical rate constants for dissociation of C2H6 to the limiting high pressure rate coefficient for association, k∞(T); it was used to fit the experimental rate coefficients using the Levenberg-Marquardt algorithm to minimize χ(2) calculated from the differences between experimental and calculated rate coefficients. Parameters for both k∞(T) and for energy transfer ⟨ΔE⟩down(T) were varied and optimized in the fitting procedure. A wide range of experimental data were fitted, covering the temperature range 300-2000 K. A high pressure limit of k∞(T) = 5.76 × 10(-11)(T/298 K)(-0.34) cm(3) molecule(-1) s(-1) was obtained, which agrees well with the best available theoretical expression.

Five-Year-Olds' Systematic Errors in Second-Order False Belief Tasks Are Due to First-Order Theory of Mind Strategy Selection : A Computational Modeling Study

NARCIS (Netherlands)

Arslan, Burcu; Taatgen, Niels A; Verbrugge, Rineke

2017-01-01

The focus of studies on second-order false belief reasoning generally was on investigating the roles of executive functions and language with correlational studies. Different from those studies, we focus on the question how 5-year-olds select and revise reasoning strategies in second-order false

Rigorous Multicomponent Reactive Separations Modelling: Complete Consideration of Reaction-Diffusion Phenomena

International Nuclear Information System (INIS)

Ahmadi, A.; Meyer, M.; Rouzineau, D.; Prevost, M.; Alix, P.; Laloue, N.

2010-01-01

This paper gives the first step of the development of a rigorous multicomponent reactive separation model. Such a model is highly essential to further the optimization of acid gases removal plants (CO 2 capture, gas treating, etc.) in terms of size and energy consumption, since chemical solvents are conventionally used. Firstly, two main modelling approaches are presented: the equilibrium-based and the rate-based approaches. Secondly, an extended rate-based model with rigorous modelling methodology for diffusion-reaction phenomena is proposed. The film theory and the generalized Maxwell-Stefan equations are used in order to characterize multicomponent interactions. The complete chain of chemical reactions is taken into account. The reactions can be kinetically controlled or at chemical equilibrium, and they are considered for both liquid film and liquid bulk. Thirdly, the method of numerical resolution is described. Coupling the generalized Maxwell-Stefan equations with chemical equilibrium equations leads to a highly non-linear Differential-Algebraic Equations system known as DAE index 3. The set of equations is discretized with finite-differences as its integration by Gear method is complex. The resulting algebraic system is resolved by the Newton- Raphson method. Finally, the present model and the associated methods of numerical resolution are validated for the example of esterification of methanol. This archetype non-electrolytic system permits an interesting analysis of reaction impact on mass transfer, especially near the phase interface. The numerical resolution of the model by Newton-Raphson method gives good results in terms of calculation time and convergence. The simulations show that the impact of reactions at chemical equilibrium and that of kinetically controlled reactions with high kinetics on mass transfer is relatively similar. Moreover, the Fick's law is less adapted for multicomponent mixtures where some abnormalities such as counter

Rethinking pedagogy for second-order differential equations: a simplified approach to understanding well-posed problems

Science.gov (United States)

Tisdell, Christopher C.

2017-07-01

Knowing an equation has a unique solution is important from both a modelling and theoretical point of view. For over 70 years, the approach to learning and teaching 'well posedness' of initial value problems (IVPs) for second- and higher-order ordinary differential equations has involved transforming the problem and its analysis to a first-order system of equations. We show that this excursion is unnecessary and present a direct approach regarding second- and higher-order problems that does not require an understanding of systems.

A tight binding model study of tunneling conductance spectra of spin and orbitally ordered CMR manganites

Science.gov (United States)

Panda, Saswati; Sahoo, D. D.; Rout, G. C.

2018-04-01

We report here a tight binding model for colossal magnetoresistive (CMR) manganites to study the pseudo gap (PG) behavior near Fermi level. In the Kubo-Ohata type DE model, we consider first and second nearest neighbor interactions for transverse spin fluctuations in core band and hopping integrals in conduction band, in the presence of static band Jahn-Teller distortion. The model Hamiltonian is solved using Zubarev's Green's function technique. The electron density of states (DOS) is found out from the Green's functions. We observe clear PG near Fermi level in the electron DOS.

Discrete pseudo-integrals

Czech Academy of Sciences Publication Activity Database

Mesiar, Radko; Li, J.; Pap, E.

2013-01-01

Roč. 54, č. 3 (2013), s. 357-364 ISSN 0888-613X R&D Projects: GA ČR GAP402/11/0378 Institutional support: RVO:67985556 Keywords : concave integral * pseudo-addition * pseudo-multiplication Subject RIV: BA - General Mathematics Impact factor: 1.977, year: 2013 http://library.utia.cas.cz/separaty/2013/E/mesiar-discrete pseudo-integrals.pdf

The oxygen evolution reaction on cobalt Part I. Reaction order experiments and impedance measurements

NARCIS (Netherlands)

Kobussen, A.G.C.; Willems, H.; Wit, J.H.W. de; Broers, G.H.J.

1984-01-01

It was found that the oxygen evolution reaction on cobalt in concentrated KOH solutions can be described differently for low and high overpotentials. In the overpotential range from 150 to 280 mV, the reaction has a Tafel slope of approximately 40 mV and a reaction order with respect to the KOH

[Altitude-belt zonality of wood vegetation within mountainous regions of the Sayan Mountains: a model of ecological second-order phase transitions ].

Science.gov (United States)

Sukhovol'skiĭ, V G; Ovchinnikova, T M; Baboĭ, S D

2014-01-01

As a description of altitude-belt zonality of wood vegetation, a model of ecological second-order transitions is proposed. Objects of the study have been chosen to be forest cenoses of the northern slope of Kulumyss Ridge (the Sayan Mauntains), while the results are comprised by the altitude profiles of wood vegetation. An ecological phase transition can be considered as the transition of cenoses at different altitudes from the state of presence of certain tree species within the studied territory to the state of their absence. By analogy with the physical model of second-order, phase transitions the order parameter is introduced (i.e., the area portion occupied by a single tree species at the certain altitude) as well as the control variable (i.e., the altitude of the wood vegetation belt). As the formal relation between them, an analog of the Landau's equation for phase transitions in physical systems is obtained. It is shown that the model is in a good accordance with the empirical data. Thus, the model can be used for estimation of upper and lower boundaries of altitude belts for individual tree species (like birch, aspen, Siberian fir, Siberian pine) as well as the breadth of their ecological niches with regard to altitude. The model includes also the parameters that describe numerically the interactions between different species of wood vegetation. The approach versatility allows to simplify description and modeling of wood vegetation altitude zonality, and enables assessment of vegetation cenoses response to climatic changes.

Pseudo-critical point in anomalous phase diagrams of simple plasma models

International Nuclear Information System (INIS)

Chigvintsev, A Yu; Iosilevskiy, I L; Noginova, L Yu

2016-01-01

Anomalous phase diagrams in subclass of simplified (“non-associative”) Coulomb models is under discussion. The common feature of this subclass is absence on definition of individual correlations for charges of opposite sign. It is e.g. modified OCP of ions on uniformly compressible background of ideal Fermi-gas of electrons OCP(∼), or a superposition of two non-ideal OCP(∼) models of ions and electrons etc. In contrast to the ordinary OCP model on non-compressible (“rigid”) background OCP(#) two new phase transitions with upper critical point, boiling and sublimation, appear in OCP(∼) phase diagram in addition to the well-known Wigner crystallization. The point is that the topology of phase diagram in OCP(∼) becomes anomalous at high enough value of ionic charge number Z . Namely, the only one unified crystal- fluid phase transition without critical point exists as continuous superposition of melting and sublimation in OCP(∼) at the interval ( Z 1 < Z < Z 2 ). The most remarkable is appearance of pseudo-critical points at both boundary values Z = Z 1 ≈ 35.5 and Z = Z 2 ≈ 40.0. It should be stressed that critical isotherm is exactly cubic in both these pseudo-critical points. In this study we have improved our previous calculations and utilized more complicated model components equation of state provided by Chabrier and Potekhin (1998 Phys. Rev. E 58 4941). (paper)

Pure perceptual-based learning of second-, third-, and fourth-order sequential probabilities.

Science.gov (United States)

Remillard, Gilbert

2011-07-01

There is evidence that sequence learning in the traditional serial reaction time task (SRTT), where target location is the response dimension, and sequence learning in the perceptual SRTT, where target location is not the response dimension, are handled by different mechanisms. The ability of the latter mechanism to learn sequential contingencies that can be learned by the former mechanism was examined. Prior research has established that people can learn second-, third-, and fourth-order probabilities in the traditional SRTT. The present study reveals that people can learn such probabilities in the perceptual SRTT. This suggests that the two mechanisms may have similar architectures. A possible neural basis of the two mechanisms is discussed.

Pseudo-potential method for taking into account the Pauli principle in cluster systems

International Nuclear Information System (INIS)

Krasnopol'skii, V.M.; Kukulin, V.I.

1975-01-01

In order to take account of the Pauli principle in cluster systems (such as 3α, α + α + n) a convenient method of renormalization of the cluster-cluster deep attractive potentials with forbidden states is suggested. The renormalization consists of adding projectors upon the occupied states with an infinite coupling constant to the initial deep potential which means that we pass to pseudo-potentials. The pseudo-potential approach in projecting upon the noneigenstates is shown to be equivalent to the orthogonality condition model of Saito et al. The orthogonality of the many-particle wave function to the forbidden states of each two-cluster sub-system is clearly demonstrated

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

Equilibrium models and kinetic for the adsorption of methylene blue on Co-hectorites

International Nuclear Information System (INIS)

Ma Jun; Jia Yongzhong; Jing Yan; Sun Jinhe; Yao Ying; Wang Xiaohua

2010-01-01

The adsorption of methylene blue (MB) onto the surface of cobalt doping hectorite (Co-hectorite) was systematically studied. The physical properties of Co-hectorites were investigated, where characterizations were carried out by X-ray diffraction (XRD) and Electron Diffraction Spectrum (EDS) techniques, and morphology was examined by nitrogen adsorption. The sample with a Co content 5% (m/m) had a higher specific surface area than other Co-hectorites. The pore diameters were distributed between 2.5 and 5.0 nm. The adsorption results revealed that Co-hectorite surfaces possessed effective interactions with MB and bases, and greatest adsorption capacity achieved with Co content 5%, where the best-fit isotherm model was the Langmuir adsorption model. Kinetic studies were fitted to the pseudo-second-order kinetic model. The intraparticle diffusion was not the rate-limiting step for the whole reaction.

Nuclear matter with a pseudo-particle model: static bulk and surface properties

International Nuclear Information System (INIS)

Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

1993-01-01

Direct calculations of cold and hot nuclear matter (bulk and surface properties) are carried out within the frame of a pseudo-particle model using a gaussian decomposition of the distribution function. Comparisons with Hartree-Fock calculations, for a large class of effective interactions, show that such a model is reliable to reproduce accurately the equation of state of nuclear matter for large ranges of densities and temperatures. The number of gaussians per nucleon and the gaussian widths are critical parameters in that semi-classical model. (orig.)

Nuclear matter with a pseudo-particle model: static bulk and surface properties

Energy Technology Data Exchange (ETDEWEB)

Idier, D. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France)); Benhassine, B. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France)); Farine, M. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France)); Remaud, B. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France)); Sebille, F. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France))

1993-11-15

Direct calculations of cold and hot nuclear matter (bulk and surface properties) are carried out within the frame of a pseudo-particle model using a gaussian decomposition of the distribution function. Comparisons with Hartree-Fock calculations, for a large class of effective interactions, show that such a model is reliable to reproduce accurately the equation of state of nuclear matter for large ranges of densities and temperatures. The number of gaussians per nucleon and the gaussian widths are critical parameters in that semi-classical model. (orig.)

Mechanism and Modelling for Sorption of Toxic Ion on Cement Kiln Dust

International Nuclear Information System (INIS)

EI- Dakroury, A.; Sayed, M.S.; EL- Sherif, E.

2009-01-01

Cement manufacturing is a critically important industry in Egypt. These industrial by-product and waste materials must be managed responsibly to insure a clean and safe environment. Cement kiln dust (CKD) is a significant by-product material of the cement manufacturing process. Cement kiln dust is a waste residue composed chiefly of oxidized, anhydrous, micron - sized particles generated as a by product of the manufacture of Portland cement. The use of cement kiln dust as adsorbent in wastewater treatment has a great attention as cheap material and clay structure. This work will discuss the basic characteristics of CKD physical and chemical properties and regulatory requirements: The batch removal of Cr(VI) from aqueous solution using low cost adsorbents such as cement kiln dust under different experimental conditions. The influences of initial Cr (VI) ion concentration (20 to 300 mg1-1) and ph (1 to 4) were investigated in this study. Adsorption of Cr (VI) is highly ph-dependent and the results indicate that the optimum ph for the removal was found to be 1 for CKD. A comparison of kinetic models applied to the adsorption of Cr (VI) ions on the CKD was evaluated for the pseudo first order, the pseudo second-order, Elovich and intra particle diffusion kinetic models, respectively. The results showed that the pseudo second-order kinetic model was found to correlate the experimental data well

Regression analysis of censored data using pseudo-observations

DEFF Research Database (Denmark)

Overgaard, Morten; Andersen, Per K.; Parner, Erik T.

2015-01-01

competing risks, the restricted mean survival-time function, and the causespecific lost-lifetime function. The pseudo-observations can be used to assess the effects of covariates on their respective functions at different times by fitting generalized linear models to the pseudo-observations. The updated...

Time scales for spinodal decomposition in nuclear matter with pseudo-particle model

Energy Technology Data Exchange (ETDEWEB)

Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

1993-12-31

Dynamical instabilities arising from fluctuations in the spinodal zone for nuclear matter are studied using a large variety of zero range interactions in the frame of a pseudo-particle model. Scale times for spinodal decomposition are extracted and a possible link with decomposition in real heavy-ion collisions is discussed. (author) 12 refs.; 6 figs.; 1 tab.

Time scales for spinodal decomposition in nuclear matter with pseudo-particle model

International Nuclear Information System (INIS)

Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

1993-01-01

Dynamical instabilities arising from fluctuations in the spinodal zone for nuclear matter are studied using a large variety of zero range interactions in the frame of a pseudo-particle model. Scale times for spinodal decomposition are extracted and a possible link with decomposition in real heavy-ion collisions is discussed. (author) 12 refs.; 6 figs.; 1 tab

Second-order theory for coupling 2D numerical and physical wave tanks: Derivation, evaluation and experimental validation

DEFF Research Database (Denmark)

Yang, Zhiwen; Liu, Shuxue; Bingham, Harry B.

2013-01-01

, 171–186] is extended to include the second-order dispersive correction. The new formulation is presented in a unified form that includes both progressive and evanescent modes and covers wavemaker configurations of the piston- and flap-type. The second order paddle stroke correction allows for improved...... nonlinear wave generation in the physical wave tank based on target numerical solutions. The performance and efficiency of the new model is first evaluated theoretically based on second order Stokes waves. Due to the complexity of the problem, the proposed method has been truncated at 2D and the treatment...... that the new second-order coupling theory provides an improvement in the quality of nonlinear wave generation when compared to existing techniques....

A pseudo three-dimensional electrochemical–thermal model of a prismatic LiFePO4 battery during discharge process

International Nuclear Information System (INIS)

Xu, Meng; Zhang, Zhuqian; Wang, Xia; Jia, Li; Yang, Lixin

2015-01-01

A lithium ion battery consists of numerous electrochemical cell units. Thermal and electrical behaviors of these local cell units have great influence on the battery's performance and safety. To study the relationship between the cell units and the battery cell, a pseudo 3D (three-dimensional) model was developed for a prismatic LiFePO 4 battery by coupling the mass, charge, and energy conservations, as well as the cell electrochemical kinetics. The model treated the battery with current collecting tabs as 3D and the local cell units as 1D. Both electrochemical and thermal characteristics of the battery were studied by using this simplified model during the discharge process. A uniformity index characterizing the SOC (state of charge) distributions among 1D cell units was also introduced. This index was used to investigate the effects of the tab placement on the uniformity of the battery cell. The placement of the positive and negative current collecting tabs on the prismatic battery was found to have a significant effect on the distributions of its potential and local reaction rates, which therefore affect the heat generation rate, and thus the temperature distribution within the battery. - Highlights: • We develop a 3D electrochemical–thermal model for a prismatic LiFePO 4 battery. • Reaction rate distribution is not in a uniform mode due to electrical gradient. • The higher reaction rate, the more quickly the heat generated in local regions. • The temperature is higher in the region close to the tabs than other regions. • Tabs placed on opposite sides will improve the uniformity of thermal distribution

Self-triggered rendezvous of gossiping second-order agents

NARCIS (Netherlands)

De Persis, Claudio; Frasca, Paolo; Hendrickx, Julien M.

2013-01-01

A recent paper by some of the authors introduced several self-triggered coordination algorithms for first-order continuous-time systems. The extension of these algorithms to second-order agents is relevant in many practical applications but presents some challenges that are tackled in this

Difference method for solving a nonlocal boundary value problem for a degenerating third-order pseudo-parabolic equation with variable coefficients

Science.gov (United States)

Beshtokov, M. Kh.

2016-10-01

A nonlocal boundary value problem for a degenerating third-order pseudo-parabolic equation with variable coefficients is considered. For solving this problem, a priori estimates in the differential and difference forms are obtained. The a priori estimates imply the uniqueness and stability of the solution on a layer with respect to the initial data and the right-hand side and the convergence of the solution of the difference problem to the solution of the differential problem.

Accelerating Pseudo-Random Number Generator for MCNP on GPU

Science.gov (United States)

Gong, Chunye; Liu, Jie; Chi, Lihua; Hu, Qingfeng; Deng, Li; Gong, Zhenghu

2010-09-01

Pseudo-random number generators (PRNG) are intensively used in many stochastic algorithms in particle simulations, artificial neural networks and other scientific computation. The PRNG in Monte Carlo N-Particle Transport Code (MCNP) requires long period, high quality, flexible jump and fast enough. In this paper, we implement such a PRNG for MCNP on NVIDIA's GTX200 Graphics Processor Units (GPU) using CUDA programming model. Results shows that 3.80 to 8.10 times speedup are achieved compared with 4 to 6 cores CPUs and more than 679.18 million double precision random numbers can be generated per second on GPU.

Three-dimensional cross-linked carbon network wrapped with ordered polyaniline nanowires for high-performance pseudo-supercapacitors

Science.gov (United States)

Hu, Huan; Liu, Shuwu; Hanif, Muddasir; Chen, Shuiliang; Hou, Haoqing

2014-12-01

The polyaniline (PANI)-based pseudo-supercapacitor has been extensively studied due to its good conductivity, ease of synthesis, low-cost monomer, tunable properties and remarkable specific capacitance. In this work, a three-dimensional cross-linked carbon network (3D-CCN) was used as a contact-resistance-free substrate for PANI-based pseudo-supercapacitors. The ordered PANI nanowires (PaNWs) were grown on the 3D-CCN to form PaNWs/3D-CCN composites by in-situ polymerization. The PaNWs/3D-CCN composites exhibited a specific capacitance (Cs) of 1191.8 F g-1 at a current density of 0.5 A g-1 and a superior rate capability with 66.4% capacitance retention at 100.0 A g-1. The high specific capacitance is attributed to the thin PaNW coating and the spaced PANI nanowire array, which ensure a higher utilization of PANI due to the ease of diffusion of protons through/on the PANI nanowires. In addition, the unique 3D-CCN was used as a high-conductivity platform (or skeleton) with no contact resistance for fast electron transfer and facile charge transport within the composites. Therefore, the binder-free composites can process rapid gains or losses of electrons and ions, even at a high current density. As a result, the specific capacitance and rate capability of our composites are remarkably higher than those of other PANI composites.

Kinetic and Thermodynamic Studies for the Removal of Europium Ions from Waste Solution Using Some Local Clay Minerals

International Nuclear Information System (INIS)

El-Kamash, A.M.; El-Masry, E.H.; El-Dessouky, M.I.

2008-01-01

Thermodynamic and kinetic investigations on the removal of Eu 3+ ions from aqueous waste solution using bentonite and sandstone, as local clay minerals, has been done using batch technique. The influences of ph, contact time between liquid and solid phases, initial metal ion concentration, and temperature have been evaluated. Pseudo first-order and pseudo second-order kinetic models were used to analyze the sorption rate data and the results showed that the pseudo second-order model is best correlate the kinetic data. Equilibrium isotherms were determined to assess the maximum sorption capacity of bentonite and sandstone and the equilibrium sorption data were analyzed using Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. All tested models fit the data reasonably well in terms of regression coefficients. The maximum sorption capacity of bentonite was found to be greater than that of sandstone and the mean free energy is in all cases in the range corresponding to the ion exchange type of sorption. Sorption studies were also performed at different temperatures to obtain the thermodynamic parameters of the process. The numerical value of δG degree decreases with an increase in temperature, indicating that the sorption reaction is more favorable at higher temperature. The positive values of δH degree correspond to the endothermic nature of the sorption process

Glycidyl methacrylate macroporous copolymer grafted with diethylene triamine as sorbent for Reactive Black 5

Directory of Open Access Journals (Sweden)

Sandić Zvjezdana P.

2014-01-01

Full Text Available In this paper, macroporous glycidyl methacrylate and ethylene glycol dimethacrylate copolymer functionalized with diethylene triamine [PGME-deta], was evaluated as Reactive Black 5 (RB5 sorbent. Batch RB5 removal from aqueous solution by PGME-deta was investigated by varying pH, contact time, sorbent dosage, initial dye concentration and temperature. The sorption is pH sensitive having maximum at pH 2 (dye removal of 85%, decreasing with the increase of pH (dye removal of 24% at pH=11 after 60 min. Sorption kinetics was fitted to chemical-reaction and particle-diffusion models (pseudo-first-order, pseudo-second-order, intraparticle diffusion and Mckay models. The pseudo-second-order kinetic model accurately predicted the RB5 amount sorbed under all investigated operating conditions, while the intraparticle diffusion was the dominant rate-limiting mechanism. The diffusion mechanism was more prevalent with the decrease in temperature and the increase in concentration. The isotherm data was best fitted with the Langmuir model, indicating homogeneous distribution of active sites on PGME-deta and monolayer sorption, with the maximum sorption capacity of 353 mg g-1. The calculated sorption rates improved with increasing temperature and an activation energy close to 40 kJ mol-1 was determined, suggesting that chemisorption was also rate-controlling. [Projekat Ministarstva nauke Republike Srbije, br. III 43009, br. TR 37021 i br. III 45001

Punishing second-order free riders before first-order free riders: The effect of pool punishment priority on cooperation

OpenAIRE

Ozono, Hiroki; Kamijo, Yoshio; Shimizu, Kazumi

2017-01-01

Second-order free riders, who do not owe punishment cost to first-order free riders in public goods games, lead to low cooperation. Previous studies suggest that for stable cooperation, it is critical to have a pool punishment system with second-order punishment, which gathers resources from group members and punishes second-order free riders as well as first-order free riders. In this study, we focus on the priority of punishment. We hypothesize that the pool punishment system that prioritiz...

Differential effects of exogenous and endogenous attention on second-order texture contrast sensitivity

Science.gov (United States)

Barbot, Antoine; Landy, Michael S.; Carrasco, Marisa

2012-01-01

The visual system can use a rich variety of contours to segment visual scenes into distinct perceptually coherent regions. However, successfully segmenting an image is a computationally expensive process. Previously we have shown that exogenous attention—the more automatic, stimulus-driven component of spatial attention—helps extract contours by enhancing contrast sensitivity for second-order, texture-defined patterns at the attended location, while reducing sensitivity at unattended locations, relative to a neutral condition. Interestingly, the effects of exogenous attention depended on the second-order spatial frequency of the stimulus. At parafoveal locations, attention enhanced second-order contrast sensitivity to relatively high, but not to low second-order spatial frequencies. In the present study we investigated whether endogenous attention—the more voluntary, conceptually-driven component of spatial attention—affects second-order contrast sensitivity, and if so, whether its effects are similar to those of exogenous attention. To that end, we compared the effects of exogenous and endogenous attention on the sensitivity to second-order, orientation-defined, texture patterns of either high or low second-order spatial frequencies. The results show that, like exogenous attention, endogenous attention enhances second-order contrast sensitivity at the attended location and reduces it at unattended locations. However, whereas the effects of exogenous attention are a function of the second-order spatial frequency content, endogenous attention affected second-order contrast sensitivity independent of the second-order spatial frequency content. This finding supports the notion that both exogenous and endogenous attention can affect second-order contrast sensitivity, but that endogenous attention is more flexible, benefitting performance under different conditions. PMID:22895879

Differential effects of exogenous and endogenous attention on second-order texture contrast sensitivity.

Science.gov (United States)

Barbot, Antoine; Landy, Michael S; Carrasco, Marisa

2012-08-15

The visual system can use a rich variety of contours to segment visual scenes into distinct perceptually coherent regions. However, successfully segmenting an image is a computationally expensive process. Previously we have shown that exogenous attention--the more automatic, stimulus-driven component of spatial attention--helps extract contours by enhancing contrast sensitivity for second-order, texture-defined patterns at the attended location, while reducing sensitivity at unattended locations, relative to a neutral condition. Interestingly, the effects of exogenous attention depended on the second-order spatial frequency of the stimulus. At parafoveal locations, attention enhanced second-order contrast sensitivity to relatively high, but not to low second-order spatial frequencies. In the present study we investigated whether endogenous attention-the more voluntary, conceptually-driven component of spatial attention--affects second-order contrast sensitivity, and if so, whether its effects are similar to those of exogenous attention. To that end, we compared the effects of exogenous and endogenous attention on the sensitivity to second-order, orientation-defined, texture patterns of either high or low second-order spatial frequencies. The results show that, like exogenous attention, endogenous attention enhances second-order contrast sensitivity at the attended location and reduces it at unattended locations. However, whereas the effects of exogenous attention are a function of the second-order spatial frequency content, endogenous attention affected second-order contrast sensitivity independent of the second-order spatial frequency content. This finding supports the notion that both exogenous and endogenous attention can affect second-order contrast sensitivity, but that endogenous attention is more flexible, benefitting performance under different conditions.

Exact calculation of three-body contact interaction to second order

International Nuclear Information System (INIS)

Kaiser, N.

2012-01-01

For a system of fermions with a three-body contact interaction the second-order contributions to the energy per particle anti E(k f ) are calculated exactly. The three-particle scattering amplitude in the medium is derived in closed analytical form from the corresponding two-loop rescattering diagram. We compare the (genuine) second-order three-body contribution to anti E(k f )∝k f 10 with the second-order term due to the density-dependent effective two-body interaction, and find that the latter term dominates. The results of the present study are of interest for nuclear many-body calculations where chiral three-nucleon forces are treated beyond leading order via a density-dependent effective two-body interaction. (orig.)

Mixed hyperbolic-second-order-parabolic formulations of general relativity

International Nuclear Information System (INIS)

Paschalidis, Vasileios

2008-01-01

Two new formulations of general relativity are introduced. The first one is a parabolization of the Arnowitt-Deser-Misner formulation and is derived by the addition of combinations of the constraints and their derivatives to the right-hand side of the Arnowitt-Deser-Misner evolution equations. The desirable property of this modification is that it turns the surface of constraints into a local attractor because the constraint propagation equations become second-order parabolic independently of the gauge conditions employed. This system may be classified as mixed hyperbolic--second-order parabolic. The second formulation is a parabolization of the Kidder-Scheel-Teukolsky formulation and is a manifestly mixed strongly hyperbolic--second-order-parabolic set of equations, bearing thus resemblance to the compressible Navier-Stokes equations. As a first test, a stability analysis of flat space is carried out and it is shown that the first modification exponentially damps and smoothes all constraint-violating modes. These systems provide a new basis for constructing schemes for long-term and stable numerical integration of the Einstein field equations.

Aspects of second-order analysis of structured inhomogeneous spatio-temporal processes

DEFF Research Database (Denmark)

Møller, Jesper; Ghorbani, Mohammad

2012-01-01

Statistical methodology for spatio-temporal point processes is in its infancy. We consider second-order analysis based on pair correlation functions and K-functions for general inhomogeneous spatio-temporal point processes and for inhomogeneous spatio-temporal Cox processes. Assuming spatio......-temporal separability of the intensity function, we clarify different meanings of second-order spatio-temporal separability. One is second-order spatio-temporal independence and relates to log-Gaussian Cox processes with an additive covariance structure of the underlying spatio-temporal Gaussian process. Another...... concerns shot-noise Cox processes with a separable spatio-temporal covariance density. We propose diagnostic procedures for checking hypotheses of second-order spatio-temporal separability, which we apply on simulated and real data....

SU(3) breaking and the pseudo-scalar spectrum in multi-taste QCD

Energy Technology Data Exchange (ETDEWEB)

Creutz, Michael

2017-06-18

Using the Sigma model to explore the lowest order pseudo-scalar spectrum with SU(3) breaking, this talk considers an additional exact "taste" symmetry to mimic species doubling. Rooting replicas of a valid approach such as Wilson fermions reproduces the desired physical spectrum. In contrast, extra symmetries of the rooted staggered approach leave spurious states and a flavor dependent taste multiplicity.

High resolution studies of pion-nucleus reaction mechanism

International Nuclear Information System (INIS)

Morris, C.L.

1983-01-01

Pion inelastic scattering is generally well described as a first order process using the DWIA. This is especially true for a large body of inelastic scattering data to low-lying collective states which is well-described by form factors obtained in (e,e') and the DWIA. Some data for which this model does not work are presented. Higher order reaction mechanisms have been invoked to explain some of these data. However, no model of these second order processes gives a satisfactory explanation of the entire data set. Experimentally, more data for pion-induced transitions to low-spin unnatural-parity states which have been studied by other probes would be useful in sorting out the reaction mechanisms responsible for the anomalous cross sections observed for the 1 + states in 12 C. Theoretically, a consistent evaluation of possible second-order diagrams in inelastic scattering, such as is being attempted for DCX 22 , would be useful

Variability and Variation in Second Language Acquisition Orders : A Dynamic Reevaluation

NARCIS (Netherlands)

Lowie, Wander; Verspoor, Marjolijn

2015-01-01

The traditional morpheme order studies in second language acquisition have tried to demonstrate the existence of a fixed order of acquisition of English morphemes, regardless of the second language learner's background. Such orders have been taken as evidence of the preprogrammed nature of language

Pseudo-differential operators on manifolds with singularities

CERN Document Server

Schulze, B-W

1991-01-01

The analysis of differential equations in domains and on manifolds with singularities belongs to the main streams of recent developments in applied and pure mathematics. The applications and concrete models from engineering and physics are often classical but the modern structure calculus was only possible since the achievements of pseudo-differential operators. This led to deep connections with index theory, topology and mathematical physics. The present book is devoted to elliptic partial differential equations in the framework of pseudo-differential operators. The first chapter contains the Mellin pseudo-differential calculus on R+ and the functional analysis of weighted Sobolev spaces with discrete and continuous asymptotics. Chapter 2 is devoted to the analogous theory on manifolds with conical singularities, Chapter 3 to manifolds with edges. Employed are pseudo-differential operators along edges with cone-operator-valued symbols.

A Signal Decomposition Method for Ultrasonic Guided Wave Generated from Debonding Combining Smoothed Pseudo Wigner-Ville Distribution and Vold–Kalman Filter Order Tracking

Directory of Open Access Journals (Sweden)

Junhua Wu

2017-01-01

Full Text Available Carbon fibre composites have a promising application future of the vehicle, due to its excellent physical properties. Debonding is a major defect of the material. Analyses of wave packets are critical for identification of the defect on ultrasonic nondestructive evaluation and testing. In order to isolate different components of ultrasonic guided waves (GWs, a signal decomposition algorithm combining Smoothed Pseudo Wigner-Ville distribution and Vold–Kalman filter order tracking is presented. In the algorithm, the time-frequency distribution of GW is first obtained by using Smoothed Pseudo Wigner-Ville distribution. The frequencies of different modes are computed based on summation of the time-frequency coefficients in the frequency direction. On the basis of these frequencies, isolation of different modes is done by Vold–Kalman filter order tracking. The results of the simulation signal and the experimental signal reveal that the presented algorithm succeeds in decomposing the multicomponent signal into monocomponents. Even though components overlap in corresponding Fourier spectrum, they can be isolated by using the presented algorithm. So the frequency resolution of the presented method is promising. Based on this, we can do research about defect identification, calculation of the defect size, and locating the position of the defect.

Pyrolytic Graphite as a Tunable Second order Neutron Filter

International Nuclear Information System (INIS)

Adib, M.

2009-01-01

A study has been carried out on the neutron transmission through pyrolytic graphite (PG) crystals in order to check its applicability as an efficient tunable second order neutron filter. The neutron transmission have been calculated as a function of neutron wavelengths in the range from 0.01 nm up to 0.7 nm at various PG mosaic spread, thickness and orientation of its c-axis with respect to the beam direction The Computer package Graphite has been used to provide the required calculation. It was shown that highly aligned (10 FWHM on mosaic spread) PG crystal ∼2 cm thick, may be tuned for optimum scattering of 2 second order neutrons within some favorable wavelength intervals in the range between 0.112 and 0.425 nm by adjusting the crystal in an appropriate orientation. .However, a less quality and thinner PG was found to almost eliminate 2 second order neutrons at only tuned values of wavelength corresponding to the poison of the triple intersection points of the curves (hkl) ± and (00l)

Kinetics and optimization on discoloration of dyeing wastewater by schorl-catalyzed fenton-like reaction

Directory of Open Access Journals (Sweden)

Xu Huan-Yan

2014-01-01

Full Text Available Kinetics and optimization on the discoloration of an active commercial dye, Argazol Blue BFBR (ABB by heterogeneous Fenton-like reaction catalyzed by natural schorl were investigated in this study. Kinetic investigations revealed that the first-order kinetic model was more favorable to describe the discoloration of ABB at different reaction conditions than the second-order and Behnajady-Modirshahla-Ghanbery models. The relationship between the reaction rate constant k and reaction temperature T followed the Arrhenius equation, with the apparent activation energy Ea of 51.31kJ•mol-1. The central composite design under the response surface methodology was employed for the experimental design and optimization of the ABB discoloration process. The significance of a second order polynomial model for predicting the optimal values of ABB discoloration was evaluated by the analysis of variance and 3D response surface plots for the interactions between two variables were constructed. Then, the optimum conditions were determined.

[Preparation of Coated CMC-Fe0 Using Rheological Phase Reaction Method and Research on Degradation of TCE in Water].

Science.gov (United States)

Fan, Wen-jing; Cheng, Yue; Yu, Shu-zhen; Fan, Xiao-feng

2015-06-01

The coated nanoscale zero-valent iron (coated CMC-Fe0) was synthesized with cheap and environment friendly CMC as the coating agent using rheological phase reaction. The sample was characterized by means of XRD, SEM, TEM and N2 adsorption-stripping and used to study reductive dechlorination of TCE. The experimental results indicated that the removal rate of TCE was about 100% when the CMC-Fe0 dosage was 6 g x L(-1), the initial TCE concentration was 5 mg x L(-1) and the reaction time was 40 h. The TCE degradation reaction of coated CMC-Fe0 followed a pseudo-first-order kinetic model. Finally, the product could be simply recovered.

Second order guiding-center Vlasov–Maxwell equations

DEFF Research Database (Denmark)

Madsen, Jens

2010-01-01

Second order gyrogauge invariant guiding-center coordinates with strong E×B-flow are derived using the Lie transformation method. The corresponding Poisson bracket structure and equations of motion are obtained. From a variational principle the explicit Vlasov–Maxwell equations are derived...

Second order finite volume scheme for Maxwell's equations with discontinuous electromagnetic properties on unstructured meshes

Energy Technology Data Exchange (ETDEWEB)

Ismagilov, Timur Z., E-mail: ismagilov@academ.org

2015-02-01

This paper presents a second order finite volume scheme for numerical solution of Maxwell's equations with discontinuous dielectric permittivity and magnetic permeability on unstructured meshes. The scheme is based on Godunov scheme and employs approaches of Van Leer and Lax–Wendroff to increase the order of approximation. To keep the second order of approximation near dielectric permittivity and magnetic permeability discontinuities a novel technique for gradient calculation and limitation is applied near discontinuities. Results of test computations for problems with linear and curvilinear discontinuities confirm second order of approximation. The scheme was applied to modelling propagation of electromagnetic waves inside photonic crystal waveguides with a bend.

Modeling and Simulation of Claus Unit Reaction Furnace

Directory of Open Access Journals (Sweden)

Maryam Pahlavan

2016-01-01

Full Text Available Reaction furnace is the most important part of the Claus sulfur recovery unit and its performance has a significant impact on the process efficiency. Too many reactions happen in the furnace and their kinetics and mechanisms are not completely understood; therefore, modeling reaction furnace is difficult and several works have been carried out on in this regard so far. Equilibrium models are commonly used to simulate the furnace, but the related literature states that the outlet of furnace is not in equilibrium and the furnace reactions are controlled by kinetic laws; therefore, in this study, the reaction furnace is simulated by a kinetic model. The predicted outlet temperature and concentrations by this model are compared with experimental data published in the literature and the data obtained by PROMAX V2.0 simulator. The results show that the accuracy of the proposed kinetic model and PROMAX simulator is almost similar, but the kinetic model used in this paper has two importance abilities. Firstly, it is a distributed model and can be used to obtain the temperature and concentration profiles along the furnace. Secondly, it is a dynamic model and can be used for analyzing the transient behavior and designing the control system.

One-neutron transfer reaction: a toy model in one dimension

International Nuclear Information System (INIS)

G. Galilei, Padova, Italy INFN, Sezione di Padova, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Padova, Italy INFN, Sezione di Padova, Padova (Italy))" >Moschini, L

2014-01-01

A simple 1D toy model to study one-neutron transfer reactions is developed. It is based on the solution of the time dependent Schroedinger equation for a particle initially bound by a fixed potential well, perturbed by a second moving potential, which accounts for the second partner of the reaction. At the end of the time evolution it is possible to evaluate the probability of the transfer of the particle from a potential to the other, as well as the transfer to continuum states in the case of weakly-bound systems. Although rather simple, the model accounts for most of the physical characteristics of these kind of reactions: such as the existence of an optimum Q-value and the dependence on the parameters defining the relative motion of the two potentials

Statistics on Lie groups: A need to go beyond the pseudo-Riemannian framework

Science.gov (United States)

Miolane, Nina; Pennec, Xavier

2015-01-01

Lie groups appear in many fields from Medical Imaging to Robotics. In Medical Imaging and particularly in Computational Anatomy, an organ's shape is often modeled as the deformation of a reference shape, in other words: as an element of a Lie group. In this framework, if one wants to model the variability of the human anatomy, e.g. in order to help diagnosis of diseases, one needs to perform statistics on Lie groups. A Lie group G is a manifold that carries an additional group structure. Statistics on Riemannian manifolds have been well studied with the pioneer work of Fréchet, Karcher and Kendall [1, 2, 3, 4] followed by others [5, 6, 7, 8, 9]. In order to use such a Riemannian structure for statistics on Lie groups, one needs to define a Riemannian metric that is compatible with the group structure, i.e a bi-invariant metric. However, it is well known that general Lie groups which cannot be decomposed into the direct product of compact and abelian groups do not admit a bi-invariant metric. One may wonder if removing the positivity of the metric, thus asking only for a bi-invariant pseudo-Riemannian metric, would be sufficient for most of the groups used in Computational Anatomy. In this paper, we provide an algorithmic procedure that constructs bi-invariant pseudo-metrics on a given Lie group G. The procedure relies on a classification theorem of Medina and Revoy. However in doing so, we prove that most Lie groups do not admit any bi-invariant (pseudo-) metric. We conclude that the (pseudo-) Riemannian setting is not the richest setting if one wants to perform statistics on Lie groups. One may have to rely on another framework, such as affine connection space.

On the ambiguity of the reaction rate constants in multivariate curve resolution for reversible first-order reaction systems.

Science.gov (United States)

Schröder, Henning; Sawall, Mathias; Kubis, Christoph; Selent, Detlef; Hess, Dieter; Franke, Robert; Börner, Armin; Neymeyr, Klaus

2016-07-13

If for a chemical reaction with a known reaction mechanism the concentration profiles are accessible only for certain species, e.g. only for the main product, then often the reaction rate constants cannot uniquely be determined from the concentration data. This is a well-known fact which includes the so-called slow-fast ambiguity. This work combines the question of unique or non-unique reaction rate constants with factor analytic methods of chemometrics. The idea is to reduce the rotational ambiguity of pure component factorizations by considering only those concentration factors which are possible solutions of the kinetic equations for a properly adapted set of reaction rate constants. The resulting set of reaction rate constants corresponds to those solutions of the rate equations which appear as feasible factors in a pure component factorization. The new analysis of the ambiguity of reaction rate constants extends recent research activities on the Area of Feasible Solutions (AFS). The consistency with a given chemical reaction scheme is shown to be a valuable tool in order to reduce the AFS. The new methods are applied to model and experimental data. Copyright © 2016 Elsevier B.V. All rights reserved.

Second order bounce back boundary condition for the lattice Boltzmann fluid simulation

International Nuclear Information System (INIS)

Kim, In Chan

2000-01-01

A new bounce back boundary method of the second order in error is proposed for the lattice Boltzmann fluid simulation. This new method can be used for the arbitrarily irregular lattice geometry of a non-slip boundary. The traditional bounce back boundary condition for the lattice Boltzmann simulation is of the first order in error. Since the lattice Boltzmann method is the second order scheme by itself, a boundary technique of the second order has been desired to replace the first order bounce back method. This study shows that, contrary to the common belief that the bounce back boundary condition is unilaterally of the first order, the second order bounce back boundary condition can be realized. This study also shows that there exists a generalized bounce back technique that can be characterized by a single interpolation parameter. The second order bounce back method can be obtained by proper selection of this parameter in accordance with the detailed lattice geometry of the boundary. For an illustrative purpose, the transient Couette and the plane Poiseuille flows are solved by the lattice Boltzmann simulation with various boundary conditions. The results show that the generalized bounce back method yields the second order behavior in the error of the solution, provided that the interpolation parameter is properly selected. Coupled with its intuitive nature and the ease of implementation, the bounce back method can be as good as any second order boundary method

Second-order oriented partial-differential equations for denoising in electronic-speckle-pattern interferometry fringes.

Science.gov (United States)

Tang, Chen; Han, Lin; Ren, Hongwei; Zhou, Dongjian; Chang, Yiming; Wang, Xiaohang; Cui, Xiaolong

2008-10-01

We derive the second-order oriented partial-differential equations (PDEs) for denoising in electronic-speckle-pattern interferometry fringe patterns from two points of view. The first is based on variational methods, and the second is based on controlling diffusion direction. Our oriented PDE models make the diffusion along only the fringe orientation. The main advantage of our filtering method, based on oriented PDE models, is that it is very easy to implement compared with the published filtering methods along the fringe orientation. We demonstrate the performance of our oriented PDE models via application to two computer-simulated and experimentally obtained speckle fringes and compare with related PDE models.

Pseudo-spectral method using rotated staggered grid for elastic wave propagation in 3D arbitrary anisotropic media

KAUST Repository

Zou, Peng

2017-05-10

Staggering grid is a very effective way to reduce the Nyquist errors and to suppress the non-causal ringing artefacts in the pseudo-spectral solution of first-order elastic wave equations. However, the straightforward use of a staggered-grid pseudo-spectral method is problematic for simulating wave propagation when the anisotropy level is greater than orthorhombic or when the anisotropic symmetries are not aligned with the computational grids. Inspired by the idea of rotated staggered-grid finite-difference method, we propose a modified pseudo-spectral method for wave propagation in arbitrary anisotropic media. Compared with an existing remedy of staggered-grid pseudo-spectral method based on stiffness matrix decomposition and a possible alternative using the Lebedev grids, the rotated staggered-grid-based pseudo-spectral method possesses the best balance between the mitigation of artefacts and efficiency. A 2D example on a transversely isotropic model with tilted symmetry axis verifies its effectiveness to suppress the ringing artefacts. Two 3D examples of increasing anisotropy levels demonstrate that the rotated staggered-grid-based pseudo-spectral method can successfully simulate complex wavefields in such anisotropic formations.

Adsorptive removal of congo red dye from aqueous solution using bael shell carbon

International Nuclear Information System (INIS)

Ahmad, Rais; Kumar, Rajeev

2010-01-01

This study investigates the potential use of bael shell carbon (BSC) as an adsorbent for the removal of congo red (CR) dye from aqueous solution. The effect of various operational parameters such as contact time, temperature, pH, and dye concentration were studied. The adsorption kinetics was modeled by first-order reversible kinetics, pseudo-first-order kinetics, and pseudo-second-order kinetics. The dye uptake process obeyed the pseudo-second-order kinetic expression at pH 5.7, 7 and 8 whereas the pseudo-first-order kinetic model was fitted well at pH 9. Langmuir, Freundlich and Temkin adsorption models were applied to fit adsorption equilibrium data. The best-fitted data was obtained with the Freundlich model. Thermodynamic study showed that adsorption of CR onto BSC was endothermic in nature and favorable with the positive ΔH o value of 13.613 kJ/mol.

Structure of the first- and second-neighbor shells of simulated water: Quantitative relation to translational and orientational order

Science.gov (United States)

Yan, Zhenyu; Buldyrev, Sergey V.; Kumar, Pradeep; Giovambattista, Nicolas; Debenedetti, Pablo G.; Stanley, H. Eugene

2007-11-01

We perform molecular dynamics simulations of water using the five-site transferable interaction potential (TIP5P) model to quantify structural order in both the first shell (defined by four nearest neighbors) and second shell (defined by twelve next-nearest neighbors) of a central water molecule. We find that the anomalous decrease of orientational order upon compression occurs in both shells, but the anomalous decrease of translational order upon compression occurs mainly in the second shell. The decreases of translational order and orientational order upon compression (called the “structural anomaly”) are thus correlated only in the second shell. Our findings quantitatively confirm the qualitative idea that the thermodynamic, structural, and hence dynamic anomalies of water are related to changes upon compression in the second shell.

Variability and Variation in Second Language Acquisition Orders: A Dynamic Reevaluation

Science.gov (United States)

Lowie, Wander; Verspoor, Marjolijn

2015-01-01

The traditional morpheme order studies in second language acquisition have tried to demonstrate the existence of a fixed order of acquisition of English morphemes, regardless of the second language learner's background. Such orders have been taken as evidence of the preprogrammed nature of language acquisition. This article argues for a…

New paradigm for simplified combustion modeling of energetic solids: Branched chain gas reaction

Energy Technology Data Exchange (ETDEWEB)

Brewster, M.Q.; Ward, M.J. [Univ. of Illinois, Urbana, IL (United States); Son, S.F. [Los Alamos National Lab., NM (United States)

1997-09-01

Two combustion models with simple but rational chemistry are compared: the classical high gas activation energy (E{sub g}/RT {much_gt} 1) Denison-Baum-Williams (DBW) model, and a new low gas activation energy (E{sub g}/RT {much_lt} 1) model recently proposed by Ward, Son, and Brewster (WSB). Both models make the same simplifying assumptions of constant properties, Lewis number unity, single-step, second order gas phase reaction, and single-step, zero order, high activation energy condensed phase decomposition. The only difference is in the gas reaction activation energy E{sub g} which is asymptotically large for DBW and vanishingly small for WSB. For realistic parameters the DBW model predicts a nearly constant temperature sensitivity {sigma}{sub p} and a pressure exponent n approaching 1. The WSB model predicts generally observed values of n = 0.7 to 0.9 and {sigma}{sub p}(T{sub o},P) with the generally observed variations with temperature (increasing) and pressure (decreasing). The WSB temperature profile also matches measured profiles better. Comparisons with experimental data are made using HMX as an illustrative example (for which WSB predictions for {sigma}{sub p}(T{sub o},P) are currently more accurate than even complex chemistry models). WSB has also shown good agreement with NC/NG double base propellant and HNF, suggesting that at the simplest level of combustion modeling, a vanishingly small gas activation energy is more realistic than an asymptotically large one. The authors conclude from this that the important (regression rate determining) gas reaction zone near the surface has more the character of chain branching than thermal decomposition.

Seepage characteristics of the second tertiary combined model

Directory of Open Access Journals (Sweden)

Huan ZHAO

2015-08-01

Full Text Available The second tertiary combined model experiment zone has been developed in Block B, Field L. The percolation feature of the second tertiary combined develop model shows great importance to rational and efficient development of the reservoir. In order to clearly illuminate its percolation feature, the typical reservoir numerical model is built by Eclipse, which is a reservoir numerical simulation software. The percolation features of original and added perforation interval under the second tertiary combined model are studied, and the variation features of general water-cut, recovery percentage, wellbore pressure, reservoir pressure and water saturation on condition of higher injection rate under the second tertiary combined model are analyzed. The research indicates that the second tertiary combined enhances the recovery of remaining oil on top of thick reservoir by developing and enhancing original perforation interval under water drive, then improves development results by polymer flooding, and gains higher recovery rate by synthetic action of water driver and polymer flooding.

THE PSEUDO-EVOLUTION OF HALO MASS

International Nuclear Information System (INIS)

Diemer, Benedikt; Kravtsov, Andrey V.; More, Surhud

2013-01-01

A dark matter halo is commonly defined as a spherical overdensity of matter with respect to a reference density, such as the critical density or the mean matter density of the universe. Such definitions can lead to a spurious pseudo-evolution of halo mass simply due to redshift evolution of the reference density, even if its physical density profile remains constant over time. We estimate the amount of such pseudo-evolution of mass between z = 1 and 0 for halos identified in a large N-body simulation, and show that it accounts for almost the entire mass evolution of the majority of halos with M 200ρ-bar ≲ 10 12 h -1 M ☉ and can be a significant fraction of the apparent mass growth even for cluster-sized halos. We estimate the magnitude of the pseudo-evolution assuming that halo density profiles remain static in physical coordinates, and show that this simple model predicts the pseudo-evolution of halos identified in numerical simulations to good accuracy, albeit with significant scatter. We discuss the impact of pseudo-evolution on the evolution of the halo mass function and show that the non-evolution of the low-mass end of the halo mass function is the result of a fortuitous cancellation between pseudo-evolution and the absorption of small halos into larger hosts. We also show that the evolution of the low-mass end of the concentration-mass relation observed in simulations is almost entirely due to the pseudo-evolution of mass. Finally, we discuss the implications of our results for the interpretation of the evolution of various scaling relations between the observable properties of galaxies and galaxy clusters and their halo masses.

Temperature dependence of third order ion molecule reactions. The reaction H+3 + 2H2 = H+5 + H2

International Nuclear Information System (INIS)

Hiraoka, K.; Kebarle, P.

1975-01-01

The rate constants k 1 for Reaction (1): H + 3 +2H 2 = H + 5 +H 2 were measured in the temperature range 100--300 degreeK. The temperature dependence of k 1 has the form k 1 proportionalT - /subn/, where n=2.3. Pierce and Porter have reported a much stronger negative temperature dependence with n=4.6. The difference arises from a determination of k 1 at 300 degreeK obtained by Arifov and used by Porter. The present k 1 (300 degreeK) =9times10 -30 (cm 6 molecules -2 center-dotsec -1 ). This is more than an order of magnitude larger than the Arifov value. The temperature dependence of third body dependent association reactions like (1) is examined on the basis of the energy transfer theory and the recently proposed trimolecular complex transition state theory by Meot-Ner, Solomon, Field, and Gershinowitz. The temperature dependence of the rate constant for the reverse reaction (-1) is obtained from k 1 and the previously determined temperature dependence of the equilibria (1). k/sub -//sub 1/ gives a good straight line Arrhenius plot leading to k/sub -//sub 1/ =8.7times10 -6 exp(-8.4/RT) cm 3 molecules -1 center-dotsec -1 . The activation energy is in kcal/mole. The preexponential factor is much larger than the rate constant for Langevin collisions. This is typical for pyrolysis of ions involving second order activation

Wavefield Extrapolation in Pseudo-depth Domain

KAUST Repository

Ma, Xuxin

2011-12-11

Wave-equation based seismic migration and inversion tools are widely used by the energy industry to explore hydrocarbon and mineral resources. By design, most of these techniques simulate wave propagation in a space domain with the vertical axis being depth measured from the surface. Vertical depth is popular because it is a straightforward mapping of the subsurface space. It is, however, not computationally cost-effective because the wavelength changes with local elastic wave velocity, which in general increases with depth in the Earth. As a result, the sampling per wavelength also increases with depth. To avoid spatial aliasing in deep fast media, the seismic wave is oversampled in shallow slow media and therefore increase the total computation cost. This issue is effectively tackled by using the vertical time axis instead of vertical depth. This is because in a vertical time representation, the "wavelength" is essentially time period for vertical rays. This thesis extends the vertical time axis to the pseudo-depth axis, which features distance unit while preserving the properties of the vertical time representation. To explore the potentials of doing wave-equation based imaging in the pseudo-depth domain, a Partial Differential Equation (PDE) is derived to describe acoustic wave in this new domain. This new PDE is inherently anisotropic because the use of a constant vertical velocity to convert between depth and vertical time. Such anisotropy results in lower reflection coefficients compared with conventional space domain modeling results. This feature is helpful to suppress the low wavenumber artifacts in reverse-time migration images, which are caused by the widely used cross-correlation imaging condition. This thesis illustrates modeling acoustic waves in both conventional space domain and pseudo-depth domain. The numerical tool used to model acoustic waves is built based on the lowrank approximation of Fourier integral operators. To investigate the potential

Brane-worlds pseudo-Goldstinos

International Nuclear Information System (INIS)

Benakli, Karim; Moura, Cesar

2008-01-01

We consider a space-time with extra dimensions containing sectors, branes and bulk, that communicate only through gravitational interactions. In each sector, if considered separately, supersymmetry could be spontaneously broken, leading to the appearance of Goldstinos. However, when taken all together, only certain combinations of the latter states turn out to be true 'would-be-Goldstinos', eaten by the gravitinos. The other (orthogonal) combinations, we call pseudo-Goldstinos, remain in the low energy spectrum. We discuss explicitly how this happen in the simplest set-up of five-dimensional space compactified on S 1 /Z 2 . Our results divide into two parts that can be considered separately. First, we build an extension of the bulk five-dimensional supergravity, by a set of new auxiliary fields, that allows coupling it to branes where supersymmetry is spontaneously broken. Second, we discuss in details the super-Higgs mechanism in the R ξ and unitary gauges, in the presence of both of a bulk Scherk-Schwarz mechanism and brane localized F-terms. This leads us to compute the gravitino mass and provide explicit formulae for the pseudo-Goldstinos spectrum

Heavy and toxic metal uptake by mesoporous hypercrosslinked SMA beads: Isotherms and kinetics

Directory of Open Access Journals (Sweden)

Renuka Gonte

2016-09-01

Full Text Available Hypercrosslinked styrene-maleic acid copolymer beads were used for the removal of metal ions from mimicked industrial effluents. The polymer was characterized by SEM which revealed the presence of a porous network. Carboxyl acid groups of the polymer were identified as active sites for metal uptake. Highly porous surface enhanced metal ion uptake was achieved through a physicochemical process. Equilibrium sorption of metal ions was best described by the Freundlich and Temkin model with R2 > 0.99. Adsorption followed pseudo first and pseudo second order reaction kinetics. Intraparticle diffusion model suggested a three step equilibrium. Desorption was a fast process with ∼90% in 60 min.

Second order phase transition in two dimensional sine-Gordon field theory - lattice model

International Nuclear Information System (INIS)

Babu Joseph, K.; Kuriakose, V.C.

1978-01-01

Two dimensional sine-Gordon (SG) field theory on a lattice is studied using the single-site basis variational method of Drell and others. The nature of the phase transition associated with the spontaneous symmetry breakdown in a SG field system is clarified to be of second order. A generalisation is offered for a SG-type field theory in two dimensions with a potential of the form [cossup(n)((square root of lambda)/m)phi-1].(author)

Differential and Difference Boundary Value Problem for Loaded Third-Order Pseudo-Parabolic Differential Equations and Difference Methods for Their Numerical Solution

Science.gov (United States)

Beshtokov, M. Kh.

2017-12-01

Boundary value problems for loaded third-order pseudo-parabolic equations with variable coefficients are considered. A priori estimates for the solutions of the problems in the differential and difference formulations are obtained. These a priori estimates imply the uniqueness and stability of the solution with respect to the initial data and the right-hand side on a layer, as well as the convergence of the solution of each difference problem to the solution of the corresponding differential problem.

Generalized second-order Coulomb phase shift functions

International Nuclear Information System (INIS)

Rosendorff, S.

1982-01-01

Some specific properties and the evaluation of the generalized second-order Coulomb phase shift functions (two-dimensional integrals of four spherical cylinder functions) are discussed. The dependence on the three momenta k 1 ,k-bar,k 2 , corresponding to the final, intermediate, and initial states is illustrated

Class of unconditionally stable second-order implicit schemes for hyperbolic and parabolic equations

International Nuclear Information System (INIS)

Lui, H.C.

The linearized Burgers equation is considered as a model u/sub t/ tau/sub x/ = bu/sub xx/, where the subscripts t and x denote the derivatives of the function u with respect to time t and space x; a and b are constants (b greater than or equal to 0). Numerical schemes for solving the equation are described that are second-order accurate, unconditionally stable, and dissipative of higher order. (U.S.)

Diffusion-limited reactions of hard-core particles in one dimension

Science.gov (United States)

Bares, P.-A.; Mobilia, M.

1999-02-01

We investigate three different methods to tackle the problem of diffusion-limited reactions (annihilation) of hard-core classical particles in one dimension. We first extend an approach devised by Lushnikov [Sov. Phys. JETP 64, 811 (1986)] and calculate for a single species the asymptotic long-time and/or large-distance behavior of the two-point correlation function. Based on a work by Grynberg and Stinchcombe [Phys. Rev. E 50, 957 (1994); Phys. Rev. Lett. 74, 1242 (1995); 76, 851 (1996)], which was developed to treat stochastic adsorption-desorption models, we provide in a second step the exact two-point (one- and two-time) correlation functions of Lushnikov's model. We then propose a formulation of the problem in terms of path integrals for pseudo- fermions. This formalism can be used to advantage in the multispecies case, especially when applying perturbative renormalization group techniques.

Perisplenic Pseudo

International Nuclear Information System (INIS)

Kim, Hyo Heon; Cho, Sin Young; Suh, Hong Kil; Kim, Ji Hyeon; Choi, Chul Soon; Lee, Eil Seong; Kang, Ik Won

1995-01-01

Perisplenic pseudo 'fluid collection' is one of the rare normal variations. Its frequency and sonographic findings for the differentiation from true perisplenic fluid collection have not been well described. Thus, we performed this study. The examination was performed with special attention to the splenic and perisplenic areas. We excluded patients with proved or suspected liver cirrhosis, pancreatic diseases,and abdominal trauma from the study population, but did not exclude the patients with chronic hepatitis and the carriers of hepatitis B virus. Of the examined 4794 patients, 8 cases showed perisplenic pseudo 'fluid collection'. Two of them were confirmed with computed tomography and liver scan, and six were inferred from the fact proved to be a part of the left lobe extension of the liver by tracing with the transducer. All cases ofperisplenic pseudo 'fluid collection' showed hypoechoic crescent area with hepatic ductal echoes. Perisplenic pseudo 'fluid collection' is very rare. The helpful findings for the differentiation from true fluid collection are the hepatic ductal echoes seen in the normal liver, proof of continuation into remained voluminous liver by tracing with the transducer. High awareness of it would prevent further unnecessary studies such as computed tomography and liver scan

Kinetics of microwave assisted extraction of pectin from Balinese orange peel using Pseudo-homogeneous model

Science.gov (United States)

Megawati, Wulansarie, Ria; Faiz, Merisa Bestari; Adi, Susatyo; Sammadikun, Waliyuddin

2018-03-01

The objective of this work was to study the homogeneous kinetics of pectin extraction of Balinese orange peel conducted using Microwave Assisted Extraction (MAE). The experimental data showed that the power increases (180 to 600 W), so that the extraction yield of pectin also increases (12.2 to 30.6 % w/w). Moreover, the extraction time is longer (10, 15, and 20 min) the yield of pectin increases (8.8, 20.2, and 40.5). At time after of 20 min (25 and 30 min), the yield starts to decrease (36.6 and 22.9). This phenomena shows pectin degradation. Therefore, pectin extraction is a series reaction, i.e. extraction and degradation. The calculation result showed that pseudo series homogeneous model can quantitatively describe the extraction kinetics. The kinetic constants can be expressed by Arrhenius equation with the frequency factors of 1.58 × 105 and 2.29 × 105 1/min, while the activation energies are 64,350 and 56,571 J/mole for extraction and degradation, respectively.

Kinetics and Isotherm of Sunset Yellow Dye Adsorption on Cadmium Sulfide Nanoparticle Loaded on Activated Carbon

Directory of Open Access Journals (Sweden)

N. Mosallanejad, A. Arami

2012-03-01

Full Text Available The objective of this study was to assess the potential of cadmium sulfide nanoparticles loaded onto activated carbon (CdSN-AC for the removal of sunset yellow (SY dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdSN-AC dose. In order to investigate the efficiency of SY adsorption on CdSN-AC, pseudo-first-order, pseudo-second-order kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. It was found that the sorption of SY onto CdSN-AC is followed by these results. 

Gravitational waves from global second order phase transitions

Energy Technology Data Exchange (ETDEWEB)

Jr, John T. Giblin [Department of Physics, Kenyon College, 201 North College Rd, Gambier, OH 43022 (United States); Price, Larry R.; Siemens, Xavier; Vlcek, Brian, E-mail: giblinj@kenyon.edu, E-mail: larryp@caltech.edu, E-mail: siemens@gravity.phys.uwm.edu, E-mail: bvlcek@uwm.edu [Center for Gravitation and Cosmology, Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States)

2012-11-01

Global second-order phase transitions are expected to produce scale-invariant gravitational wave spectra. In this manuscript we explore the dynamics of a symmetry-breaking phase transition using lattice simulations. We explicitly calculate the stochastic gravitational wave background produced during the transition and subsequent self-ordering phase. We comment on this signal as it compares to the scale-invariant spectrum produced during inflation.

Heterogeneous photocatalysis of real textile wastewater: evaluation of reaction kinetics and characterization.

Science.gov (United States)

Sahoo, Chittaranjan; Gupta, Ashok K; Pillai, Indu M Sasidharan

2012-01-01

Real textile wastewater collected from the cotton dyeing bath of a fabric dyeing and finishing plant was subjected to heterogeneous photocatalysis using Ag(+) doped TiO(2) under UV irradiation in a batch reactor. The photocatalysts were characterized by FESEM, XRD, EDS, FTIR, DRS and BET analyses. The kinetics of the reaction was also evaluated. Colour removal was more than 88%, 94% and 99%, respectively for undiluted, 2 times diluted and 5 times diluted wastewater with Ag(+) doped TiO(2) (2.5 g/L) after UV irradiation for 360 minutes. The COD removal for undiluted, 2 times diluted and 5 times diluted wastewater was 47%, 70% and 92%, respectively under similar conditions. The reaction followed Langmuir-Hinshelwood pseudo first order kinetic model and the data fitted well to polynomial regression analysis.

Contrast gain control in first- and second-order motion perception.

Science.gov (United States)

Lu, Z L; Sperling, G

1996-12-01

A novel pedestal-plus-test paradigm is used to determine the nonlinear gain-control properties of the first-order (luminance) and the second-order (texture-contrast) motion systems, that is, how these systems' responses to motion stimuli are reduced by pedestals and other masking stimuli. Motion-direction thresholds were measured for test stimuli consisting of drifting luminance and texture-contrast-modulation stimuli superimposed on pedestals of various amplitudes. (A pedestal is a static sine-wave grating of the same type and same spatial frequency as the moving test grating.) It was found that first-order motion-direction thresholds are unaffected by small pedestals, but at pedestal contrasts above 1-2% (5-10 x pedestal threshold), motion thresholds increase proportionally to pedestal amplitude (a Weber law). For first-order stimuli, pedestal masking is specific to the spatial frequency of the test. On the other hand, motion-direction thresholds for texture-contrast stimuli are independent of pedestal amplitude (no gain control whatever) throughout the accessible pedestal amplitude range (from 0 to 40%). However, when baseline carrier contrast increases (with constant pedestal modulation amplitude), motion thresholds increase, showing that gain control in second-order motion is determined not by the modulator (as in first-order motion) but by the carrier. Note that baseline contrast of the carrier is inherently independent of spatial frequency of the modulator. The drastically different gain-control properties of the two motion systems and prior observations of motion masking and motion saturation are all encompassed in a functional theory. The stimulus inputs to both first- and second-order motion process are normalized by feedforward, shunting gain control. The different properties arise because the modulator is used to control the first-order gain and the carrier is used to control the second-order gain.

Second-order two-scale method for bending behaviors of composite plate with periodic configuration

International Nuclear Information System (INIS)

Zhu Guoqing; Cui Junzhi

2010-01-01

In this paper, the second-order two-scale analysis method for bending behaviors of the plate made from composites with 3-D periodic configuration is presented by means of construction way. It can capture the microscopic 3-D mechanics behaviors caused from 3-D micro-structures. First, directly starting from the 3-D elastic plate model of composite materials with 3-D periodic configuration, three cell models are defined, and correspondingly the three classes of cell functions only defined on 3 normalized cells are constructed. And then, the effective homogenization parameters of composites are calculated from those local functions, it leads to a 2-D homogenized laminar plate problem. Next, to solve it the homogenization solution is obtained. Finally, the second-order two-scale solution is constructed from the micro-cell functions and the homogenization solution.

Second-order advantage with excitation-emission photoinduced fluorimetry for the determination of the antiepileptic carbamazepine in environmental waters.

Science.gov (United States)

Lozano, Valeria A; Escandar, Graciela M

2013-06-11

A photochemically induced fluorescence system combined with second-order chemometric analysis for the determination of the anticonvulsant carbamazepine (CBZ) is presented. CBZ is a widely used drug for the treatment of epilepsy and is included in the group of emerging contaminant present in the aquatic environment. CBZ is not fluorescent in solution but can be converted into a fluorescent compound through a photochemical reaction in a strong acid medium. The determination is carried out by measuring excitation-emission photoinduced fluorescence matrices of the products formed upon ultraviolet light irradiation in a laboratory-constructed reactor constituted by two simple 4 W germicidal tubes. Working conditions related to both the reaction medium and the photoreactor geometry are optimized by an experimental design. The developed approach enabled the determination of CBZ at trace levels without the necessity of applying separation steps, and in the presence of uncalibrated interferences which also display photoinduced fluorescence and may be potentially present in the investigated samples. Different second-order algorithms were tested and successful resolution was achieved using multivariate curve resolution-alternating least-squares (MCR-ALS). The study is employed for the discussion of the scopes and yields of each of the applied second-order chemometric tools. The quality of the proposed method is probed through the determination of the studied emerging pollutant in both environmental and drinking water samples. After a pre-concentration step on a C18 membrane using 50.0 mL of real water samples, a prediction relative error of 2% and limits of detection and quantification of 0.2 and 0.6 ng mL(-1) were respectively obtained. Copyright © 2013 Elsevier B.V. All rights reserved.

On the second-order temperature jump coefficient of a dilute gas

Science.gov (United States)

Radtke, Gregg A.; Hadjiconstantinou, N. G.; Takata, S.; Aoki, K.

2012-09-01

We use LVDSMC simulations to calculate the second-order temperature jump coefficient for a dilute gas whose temperature is governed by the Poisson equation with a constant forcing term. Both the hard sphere gas and the BGK model of the Boltzmann equation are considered. Our results show that the temperature jump coefficient is different from the well known linear and steady case where the temperature is governed by the homogeneous heat conduction (Laplace) equation.

Geometrical foundations of continuum mechanics an application to first- and second-order elasticity and elasto-plasticity

CERN Document Server

Steinmann, Paul

2015-01-01

This book illustrates the deep roots of the geometrically nonlinear kinematics of generalized continuum mechanics in differential geometry. Besides applications to first- order elasticity and elasto-plasticity an appreciation thereof is particularly illuminating for generalized models of continuum mechanics such as second-order (gradient-type) elasticity and elasto-plasticity.   After a motivation that arises from considering geometrically linear first- and second- order crystal plasticity in Part I several concepts from differential geometry, relevant for what follows, such as connection, parallel transport, torsion, curvature, and metric for holonomic and anholonomic coordinate transformations are reiterated in Part II. Then, in Part III, the kinematics of geometrically nonlinear continuum mechanics are considered. There various concepts of differential geometry, in particular aspects related to compatibility, are generically applied to the kinematics of first- and second- order geometrically nonlinear con...

Neural network and parton two fireball model for pseudo-rapidity distribution in proton-proton collision

International Nuclear Information System (INIS)

El-Bakry, M.Y.

2000-01-01

Pseudo-Rapidity distribution of created pions from proton-proton (p-p) interaction has been studied in the framework of artificial neural network (ANN) and the parton two fireball model (PTFM). The predicted distributions from the ANN based model and the parton two fireball model is compared with the corresponding experimental results. The ANN model has proved better matching for experimental data specially at high energies where the conventional two fireball model representation deteriorates

Highly Dispersed Pseudo-Homogeneous and Heterogeneous Catalysts Synthesized via Inverse Micelle Solutions for the Liquefaction of Coal

Energy Technology Data Exchange (ETDEWEB)

Hampden-Smith, M.; Kawola, J.S.; Martino, A.; Sault, A.G.; Yamanaka, S.A.

1999-01-05

The mission of this project was to use inverse micelle solutions to synthesize nanometer sized metal particles and test the particles as catalysts in the liquefaction of coal and other related reactions. The initial focus of the project was the synthesis of iron based materials in pseudo-homogeneous form. The frost three chapters discuss the synthesis, characterization, and catalyst testing in coal liquefaction and model coal liquefaction reactions of iron based pseudo-homogeneous materials. Later, we became interested in highly dispersed catalysts for coprocessing of coal and plastic waste. Bifunctional catalysts . to hydrogenate the coal and depolymerize the plastic waste are ideal. We began studying, based on our previously devised synthesis strategies, the synthesis of heterogeneous catalysts with a bifunctional nature. In chapter 4, we discuss the fundamental principles in heterogeneous catalysis synthesis with inverse micelle solutions. In chapter 5, we extend the synthesis of chapter 4 to practical systems and use the materials in catalyst testing. Finally in chapter 6, we return to iron and coal liquefaction now studied with the heterogeneous catalysts.

High-order upwind schemes for the wave equation on overlapping grids: Maxwell's equations in second-order form

Science.gov (United States)

Angel, Jordan B.; Banks, Jeffrey W.; Henshaw, William D.

2018-01-01

High-order accurate upwind approximations for the wave equation in second-order form on overlapping grids are developed. Although upwind schemes are well established for first-order hyperbolic systems, it was only recently shown by Banks and Henshaw [1] how upwinding could be incorporated into the second-order form of the wave equation. This new upwind approach is extended here to solve the time-domain Maxwell's equations in second-order form; schemes of arbitrary order of accuracy are formulated for general curvilinear grids. Taylor time-stepping is used to develop single-step space-time schemes, and the upwind dissipation is incorporated by embedding the exact solution of a local Riemann problem into the discretization. Second-order and fourth-order accurate schemes are implemented for problems in two and three space dimensions, and overlapping grids are used to treat complex geometry and problems with multiple materials. Stability analysis of the upwind-scheme on overlapping grids is performed using normal mode theory. The stability analysis and computations confirm that the upwind scheme remains stable on overlapping grids, including the difficult case of thin boundary grids when the traditional non-dissipative scheme becomes unstable. The accuracy properties of the scheme are carefully evaluated on a series of classical scattering problems for both perfect conductors and dielectric materials in two and three space dimensions. The upwind scheme is shown to be robust and provide high-order accuracy.

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....

Massless second-order tetradic spin-3 and higher-helicity bosons

Energy Technology Data Exchange (ETDEWEB)

Aragone, C; La Roche, H [Universidad Simon Bolivar, Caracas (Venezuela) Dept. de Fisica

1982-11-21

The unique, uniform, second-order formulation of massless bosons of helicity >=3 is presented here in terms of tetradic fields. The actions we find are shown to coincide both with the first-order (tetradic) formulation of Vasiliev and with the symmetric second-order description of Fronsdal. We carefully analyse the gravitational coupling of the spin-3 field and find that tetradic spin-3 matter presents the same translational consistency problem as symmetric matter does. Furthermore, in the curved tetradic case the generalized Lorentz invariance can be restored by the addition of nominimal terms.

Adaptive suboptimal second-order sliding mode control for microgrids

Science.gov (United States)

Incremona, Gian Paolo; Cucuzzella, Michele; Ferrara, Antonella

2016-09-01

This paper deals with the design of adaptive suboptimal second-order sliding mode (ASSOSM) control laws for grid-connected microgrids. Due to the presence of the inverter, of unpredicted load changes, of switching among different renewable energy sources, and of electrical parameters variations, the microgrid model is usually affected by uncertain terms which are bounded, but with unknown upper bounds. To theoretically frame the control problem, the class of second-order systems in Brunovsky canonical form, characterised by the presence of matched uncertain terms with unknown bounds, is first considered. Four adaptive strategies are designed, analysed and compared to select the most effective ones to be applied to the microgrid case study. In the first two strategies, the control amplitude is continuously adjusted, so as to arrive at dominating the effect of the uncertainty on the controlled system. When a suitable control amplitude is attained, the origin of the state space of the auxiliary system becomes attractive. In the other two strategies, a suitable blend between two components, one mainly working during the reaching phase, the other being the predominant one in a vicinity of the sliding manifold, is generated, so as to reduce the control amplitude in steady state. The microgrid system in a grid-connected operation mode, controlled via the selected ASSOSM control strategies, exhibits appreciable stability properties, as proved theoretically and shown in simulation.

Reactions of enolisable ketones with dichloroisocyanuric acid in absence and presence of added chloride ions – a kinetic study

Directory of Open Access Journals (Sweden)

Y. L. Kumar

2015-01-01

Full Text Available Kinetics of reactions of enolisable ketones (S = acetone/2-butanone with dichloroisocyanuric acid (DCICA were studied in aqueous acetic acid and perchloric acid media in absence and presence of added chloride ions. The reactions were found to be pseudo zero order and pseudo first order on [DCICA] in absence and presence of chloride ions respectively. Both in presence and absence of chloride ions, first order and fractional order in substrate and perchloric acid were observed respectively. An increase in the rate of reaction was observed with an increase in chloride ion concentration as well as acetic acid composition. The results were interpreted in terms of probable mechanisms involving (i rate-determining enol formation from the conjugate acid of the ketone (SH+ in the absence of added chloride ions and (ii rate-determining interaction of SH+ with the most effective molecular chlorine species produced by the hydrolysis of DCICA (rather than a rate-determining interaction of enol with chlorine in the presence of added chloride ions, prior to the rapid steps of product formation. DOI: http://dx.doi.org/10.4314/bcse.v29i1.12

Investigation of second-order optical potential for elastic π4He scattering

International Nuclear Information System (INIS)

Mach, R.; Sapozhnikov, M.G.

1982-01-01

The calculations of elastic π - 4 He scattering within the framework of the optical model with a second-order potential were performed. The effects of recoil correlations, charge exchange and double spin (isospin) flip in the inter-- mediate states are studied. The correction of the impulse approximation is investigated. Comparison between Kerman-McManus-Thaler and Watson formalisms is made

Degeneracy of energy levels of pseudo-Gaussian oscillators

International Nuclear Information System (INIS)

Iacob, Theodor-Felix; Iacob, Felix; Lute, Marina

2015-01-01

We study the main features of the isotropic radial pseudo-Gaussian oscillators spectral properties. This study is made upon the energy levels degeneracy with respect to orbital angular momentum quantum number. In a previous work [6] we have shown that the pseudo-Gaussian oscillators belong to the class of quasi-exactly solvable models and an exact solution has been found

Improved system blind identification based on second-order ...

Indian Academy of Sciences (India)

An improved system blind identification method based on second- order cyclostationary statistics and the properties of group delay, has been ... In the last decade, there has been considerable research on achieving blind identification.

Concordance measures and second order stochastic dominance-portfolio efficiency analysis

Czech Academy of Sciences Publication Activity Database

Kopa, Miloš; Tichý, T.

2012-01-01

Roč. 15, č. 4 (2012), s. 110-120 ISSN 1212-3609 R&D Projects: GA ČR(CZ) GBP402/12/G097 Institutional support: RVO:67985556 Keywords : dependency * concordance * portfolio selection * second order stochastic dominance Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.633, year: 2012 http://library.utia.cas.cz/separaty/2013/E/kopa-concordance measures and second order stochastic dominance- portfolio efficiency analysis.pdf

Pseudo-Riemannian Novikov algebras

Energy Technology Data Exchange (ETDEWEB)

Chen Zhiqi; Zhu Fuhai [School of Mathematical Sciences and LPMC, Nankai University, Tianjin 300071 (China)], E-mail: chenzhiqi@nankai.edu.cn, E-mail: zhufuhai@nankai.edu.cn

2008-08-08

Novikov algebras were introduced in connection with the Poisson brackets of hydrodynamic-type and Hamiltonian operators in formal variational calculus. Pseudo-Riemannian Novikov algebras denote Novikov algebras with non-degenerate invariant symmetric bilinear forms. In this paper, we find that there is a remarkable geometry on pseudo-Riemannian Novikov algebras, and give a special class of pseudo-Riemannian Novikov algebras.

The effects of second-order hydrodynamics on a semisubmersible floating offshore wind turbine

International Nuclear Information System (INIS)

Bayati, I; Jonkman, J; Robertson, A; Platt, A

2014-01-01

The objective of this paper is to assess the second-order hydrodynamic effects on a semisubmersible floating offshore wind turbine. Second-order hydrodynamics induce loads and motions at the sum- and difference-frequencies of the incident waves. These effects have often been ignored in offshore wind analysis, under the assumption that they are significantly smaller than first-order effects. The sum- and difference-frequency loads can, however, excite eigenfrequencies of a floating system, leading to large oscillations that strain the mooring system or vibrations that cause fatigue damage to the structure. Observations of supposed second-order responses in wave-tank tests performed by the DeepCwind consortium at the Maritime Research Institute Netherlands (MARIN) offshore basin suggest that these effects might be more important than originally expected. These observations inspired interest in investigating how second-order excitation affects floating offshore wind turbines and whether second-order hydrodynamics should be included in offshore wind simulation tools like FAST. In this work, the effects of second-order hydrodynamics on a floating semisubmersible offshore wind turbine are investigated. Because FAST is currently unable to account for second-order effects, a method to assess these effects was applied in which linearized properties of the floating wind system derived from FAST (including the 6x6 mass and stiffness matrices) are used by WAMIT to solve the first- and second-order hydrodynamics problems in the frequency domain. The method was applied to the Offshore Code Comparison Collaboration Continuation OC4-DeepCwind semisubmersible platform, supporting the National Renewable Energy Laboratory's 5-MW baseline wind turbine. In this paper, the loads and response of the system caused by the second-order hydrodynamics are analysed and compared to the first-order hydrodynamic loads and induced motions in the frequency domain. Further, the second-order

Pseudo LRM waveforms from CryoSat SARin acquisition

Science.gov (United States)

Scagliola, Michele; Fornari, Marco; Bouffard, Jerome; Parrinello, Tommaso; Féménias, Pierre

2016-04-01

CryoSat was launched on the 8th April 2010 and is the first European ice mission dedicated to the monitoring of precise changes in the thickness of polar ice sheets and floating sea ice. The main payload of CryoSat is a Ku-band pulsewidth limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter). When commanded in SARIn (synthetic aperture radar interferometry) mode, through coherent along-track processing of the returns received from two antennas, the interferometric phase related to the first arrival of the echo is used to retrieve the angle of arrival of the scattering in the across-track direction. When SIRAL operates in SAR or SARin mode, the obtained waveforms have an along-track resolution and a speckle reduction which is increased with respect to the pulse-limited waveforms. Anyway, in order to analyze the continuity of the geophysical retrieved parameters among different acquisition modes, techniques to transform SARin mode data to pseudo-LRM mode data are welcome. The transformation process is known as SAR reduction and it is worth recalling here that only approximate pseudo-LRM waveforms can be obtained in case of closed burst acquisitions, as SIRAL operates. A SAR reduction processing scheme has been developed to obtain pseudo-LRM waveforms from CryoSat SARin acquisition. As a trade-off between the along-track length on Earth surface contributing to one SARin pseudo-LRM waveform and the noisiness of the waveform itself, it has been chosen a SAR reduction approach based on the averaging of all the SARin echoes received each 20Hz, resulting in one pseudo-LRM waveform for each SARin burst given the SARin burst repetition period. SARin pseudo-LRM waveforms have been produced for CryoSat acquisition both on ice and sea surfaces, aiming at verifying the continuity of the retracked surface height over the ellipsoid between genuine LRM products and pseudo-LRM products. Moreover, the retracked height from the SARin pseudo-LRM has been

SIMULTANEOUS ABSORPTION AND DESORPTION WITH REVERSIBLE 1ST-ORDER CHEMICAL-REACTION - ANALYTICAL SOLUTION AND NEGATIVE ENHANCEMENT FACTORS

NARCIS (Netherlands)

WINKELMAN, JGM; BEENACKERS, AACM

The problem of ps absorption accompanied by a first-order reversible reaction, producing a volatile reaction product, is considered. A general analytical solution is developed for the film model, resulting in explicit relations for the concentration profiles in the film and for the mass transfer

Removal of three nitrophenols from aqueous solutions by adsorption onto char ash: equilibrium and kinetic modeling

Science.gov (United States)

Magdy, Yehia M.; Altaher, Hossam; ElQada, E.

2018-03-01

In this research, the removal of 2,4 dinitrophenol, 2 nitrophenol and 4 nitrophenol from aqueous solution using char ash from animal bones was investigated using batch technique. Three 2-parameter isotherms (Freundlich, Langmuir, and Temkin) were applied to analyze the experimental data. Both linear and nonlinear regression analyses were performed for these models to estimate the isotherm parameters. Three 3-parameter isotherms (Redlich-Peterson, Sips, Toth) were also tested. Moreover, the kinetic data were tested using pseudo-first order, pseudo-second order, Elovich, Intraparticle diffusion and Boyd methods. Langmuir adsorption isotherm provided the best fit for the experimental data indicating monolayer adsorption. The maximum adsorption capacity was 8.624, 7.55, 7.384 mg/g for 2 nitrophenol, 2,4 dinitrophenol, and 4 nitrophenol, respectively. The experimental data fitted well to pseudo-second order model suggested a chemical nature of the adsorption process. The R 2 values for this model were 0.973 up to 0.999. This result with supported by the Temkin model indicating heat of adsorption to be greater than 10 kJ/mol. The rate controlling step was intraparticle diffusion for 2 nitrophenol, and a combination of intraparticle diffusion and film diffusion for the other two phenols. The pH and temperature of solution were found to have a considerable effect, and the temperature indicated the exothermic nature of the adsorption process. The highest adsorption capacity was obtained at pH 9 and 25 °C.

An integral for second-order multiple scattering perturbation theory

International Nuclear Information System (INIS)

Hoffman, G.G.

1997-01-01

This paper presents the closed form evaluation of a six-dimensional integral. The integral arises in the application to many-electron systems of a multiple scattering perturbation expansion at second order when formulated in fourier space. The resulting function can be used for the calculation of both the electron density and the effective one-electron potential in an SCF calculations. The closed form expression derived here greatly facilitates these calculations. In addition, the evaluated integral can be used for the computation of second-order corrections to the open-quotes optimized Thomas-Fermi theory.close quotes 10 refs., 2 figs

Perisplenic Pseudo

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyo Heon; Cho, Sin Young; Suh, Hong Kil; Kim, Ji Hyeon; Choi, Chul Soon; Lee, Eil Seong; Kang, Ik Won [Hallym University College of Medicine, Chuncheon (Korea, Republic of)

1995-12-15

Perisplenic pseudo 'fluid collection' is one of the rare normal variations. Its frequency and sonographic findings for the differentiation from true perisplenic fluid collection have not been well described. Thus, we performed this study. The examination was performed with special attention to the splenic and perisplenic areas. We excluded patients with proved or suspected liver cirrhosis, pancreatic diseases,and abdominal trauma from the study population, but did not exclude the patients with chronic hepatitis and the carriers of hepatitis B virus. Of the examined 4794 patients, 8 cases showed perisplenic pseudo 'fluid collection'. Two of them were confirmed with computed tomography and liver scan, and six were inferred from the fact proved to be a part of the left lobe extension of the liver by tracing with the transducer. All cases ofperisplenic pseudo 'fluid collection' showed hypoechoic crescent area with hepatic ductal echoes. Perisplenic pseudo 'fluid collection' is very rare. The helpful findings for the differentiation from true fluid collection are the hepatic ductal echoes seen in the normal liver, proof of continuation into remained voluminous liver by tracing with the transducer. High awareness of it would prevent further unnecessary studies such as computed tomography and liver scan

Pseudo SU(3) shell model: Normal parity bands in odd-mass nuclei

International Nuclear Information System (INIS)

Vargas, C.E.; Hirsch, J.G.; Draayer, J.P.

2000-01-01

A pseudo shell SU(3) model description of normal parity bands in 159 Tb is presented. The Hamiltonian includes spherical Nilsson single-particle energies, the quadrupole-quadrupole and pairing interactions, as well as three rotor terms. A systematic parametrization is introduced, accompanied by a detailed discussion of the effect each term in the Hamiltonian has on the energy spectrum. Yrast and excited band wavefunctions are analyzed together with their B(E2) values

Ametryn degradation by aqueous chlorine: Kinetics and reaction influences

International Nuclear Information System (INIS)

Xu Bin; Gao Naiyun; Cheng Hefa; Hu Chenyan; Xia Shengji; Sun Xiaofeng; Wang Xuejiao; Yang Shaogui

2009-01-01

The chemical oxidation of the herbicide ametryn was investigated by aqueous chlorination between pH 4 and 10 at a temperature of 25 deg. C. Ametryn was found to react very rapidly with aqueous chlorine. The reaction kinetics can be well described by a second-order kinetic model. The apparent second-order rate constants are greater than 5 x 10 2 M -1 s -1 under acidic and neutral conditions. The reaction proceeds much more slowly under alkaline conditions. The predominant reactions were found to be the reactions of HOCl with neutral ametryn and the charged ametryn, with rate constants equal to 7.22 x 10 2 and 1.58 x 10 3 M -1 s -1 , respectively. The ametryn degradation rate increases with addition of bromide and decreases with addition of ammonia during the chlorination process. Based on elementary chemical reactions, a kinetic model of ametryn degradation by chlorination in the presence of bromide or ammonia ion was also developed. By employing this model, we estimate that the rate constants for the reactions of HOBr with neutral ametryn and charged ametryn were 9.07 x 10 3 and 3.54 x 10 6 M -1 s -1 , respectively. These values are 10- to 10 3 -fold higher than those of HOCl, suggesting that the presence of bromine species during chlorination could significantly accelerate ametryn degradation.

Laboratory studies on the adsorption kinetics of 137Cs in sediment

International Nuclear Information System (INIS)

Jaison, T.J.; Patra, A.K.; Ravi, P.M.; Sarkar, P.K.

2012-01-01

During the operation of a nuclear reactor, extreme care is taken to minimize the release of radionuclides to the environment. Low level radioactive liquid waste generated is treated and released to the nearest water body after monitoring to ensure that the activity levels are well within the regulatory limits. Environmental Survey Laboratories (ESL) attached to power plants carry out a systematic environmental monitoring and impact assessment to ensure that the dose to the member of public is well within the limits. This paper presents the results of a systematic laboratory study carried out at ESL, Kakrapar Atomic Power Station (KAPS) on the adsorption kinetics of 137 Cs in sediment. The study is to evaluate the sorption kinetics of 137 Cs + onto site specific sediment. Sets of adsorption experiments were conducted at specific time intervals for two different 137 Cs + concentrations, keeping other experimental conditions same. The kinetics of 137 Cs + adsorption on sediment is analyzed using pseudo first order, pseudo second order, and intra-particle diffusion kinetic models. The pseudo-second order kinetic model is better correlated with the kinetics data compared with the pseudo first-order model. This indicates 137 Cs + ions can be involved in chemical bonding during the adsorption process to the analysed sediment. This chemi-sorption processes show a good compliance with the pseudo-second order kinetic model. It is also evident that lower concentration exhibits greater adsorption rate (k 2 value is 1.85 x 10 -5 Bq g -1 min -1 for 1245 Bq sets and 1.05 x 10 -5 Bq g -1 min -1 for 2456 Bq sets) from the pseudo second order model. Intra-particle diffusion rate constants (K id ) were also obtained by two different models for both the concentrations and found to be higher for higher concentration. (author)

Solution of second order supersymmetrical intertwining relations in Minkowski plane

Energy Technology Data Exchange (ETDEWEB)

Ioffe, M. V., E-mail: m.ioffe@spbu.ru; Kolevatova, E. V., E-mail: e.v.kolev@yandex.ru [Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034 (Russian Federation); Nishnianidze, D. N., E-mail: cutaisi@yahoo.com [Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034 (Russian Federation); Akaki Tsereteli State University, 4600 Kutaisi, Georgia (United States)

2016-08-15

Supersymmetrical (SUSY) intertwining relations are generalized to the case of quantum Hamiltonians in Minkowski space. For intertwining operators (supercharges) of second order in derivatives, the intertwined Hamiltonians correspond to completely integrable systems with the symmetry operators of fourth order in momenta. In terms of components, the intertwining relations correspond to the system of nonlinear differential equations which are solvable with the simplest—constant—ansatzes for the “metric” matrix in second order part of the supercharges. The corresponding potentials are built explicitly both for diagonalizable and nondiagonalizable form of “metric” matrices, and their properties are discussed.

Accelerating distributed average consensus by exploring the information of second-order neighbors

Energy Technology Data Exchange (ETDEWEB)

Yuan Deming [School of Automation, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu (China); Xu Shengyuan, E-mail: syxu02@yahoo.com.c [School of Automation, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu (China); Zhao Huanyu [School of Automation, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu (China); Chu Yuming [Department of Mathematics, Huzhou Teacher' s College, Huzhou 313000, Zhejiang (China)

2010-05-17

The problem of accelerating distributed average consensus by using the information of second-order neighbors in both the discrete- and continuous-time cases is addressed in this Letter. In both two cases, when the information of second-order neighbors is used in each iteration, the network will converge with a speed faster than the algorithm only using the information of first-order neighbors. Moreover, the problem of using partial information of second-order neighbors is considered, and the edges are not chosen randomly from second-order neighbors. In the continuous-time case, the edges are chosen by solving a convex optimization problem which is formed by using the convex relaxation method. In the discrete-time case, for small network the edges are chosen optimally via the brute force method. Finally, simulation examples are provided to demonstrate the effectiveness of the proposed algorithm.

Transport coefficients in second-order non-conformal viscous hydrodynamics

International Nuclear Information System (INIS)

Ryblewski, Radoslaw

2015-01-01

Based on the exact solution of Boltzmann kinetic equation in the relaxation-time approximation, the precision of the two most recent formulations of relativistic second-order non-conformal viscous hydrodynamics (14-moment approximation and causal Chapman-Enskog method), standard Israel-Stewart theory, and anisotropic hydrodynamics framework, in the simple case of one-dimensional Bjorken expansion, is tested. It is demonstrated that the failure of Israel-Stewart theory in reproducing exact solutions of the Boltzmann kinetic equation occurs due to neglecting and/or choosing wrong forms of some of the second-order transport coefficients. In particular, the importance of shear-bulk couplings in the evolution equations for dissipative quantities is shown. One finds that, in the case of the bulk viscous pressure correction, such coupling terms are as important as the corresponding first-order Navier-Stokes term and must be included in order to obtain, at least qualitative, overall agreement with the kinetic theory. (paper)

Metrics on the Phase Space and Non-Selfadjoint Pseudo-Differential Operators

CERN Document Server

Lerner, Nicolas

2010-01-01

This book is devoted to the study of pseudo-differential operators, with special emphasis on non-selfadjoint operators, a priori estimates and localization in the phase space. We expose the most recent developments of the theory with its applications to local solvability and semi-classical estimates for nonselfadjoint operators. The first chapter is introductory and gives a presentation of classical classes of pseudo-differential operators. The second chapter is dealing with the general notion of metrics on the phase space. We expose some elements of the so-called Wick calculus and introduce g

Robust second-order scheme for multi-phase flow computations

Science.gov (United States)

Shahbazi, Khosro

2017-06-01

A robust high-order scheme for the multi-phase flow computations featuring jumps and discontinuities due to shock waves and phase interfaces is presented. The scheme is based on high-order weighted-essentially non-oscillatory (WENO) finite volume schemes and high-order limiters to ensure the maximum principle or positivity of the various field variables including the density, pressure, and order parameters identifying each phase. The two-phase flow model considered besides the Euler equations of gas dynamics consists of advection of two parameters of the stiffened-gas equation of states, characterizing each phase. The design of the high-order limiter is guided by the findings of Zhang and Shu (2011) [36], and is based on limiting the quadrature values of the density, pressure and order parameters reconstructed using a high-order WENO scheme. The proof of positivity-preserving and accuracy is given, and the convergence and the robustness of the scheme are illustrated using the smooth isentropic vortex problem with very small density and pressure. The effectiveness and robustness of the scheme in computing the challenging problem of shock wave interaction with a cluster of tightly packed air or helium bubbles placed in a body of liquid water is also demonstrated. The superior performance of the high-order schemes over the first-order Lax-Friedrichs scheme for computations of shock-bubble interaction is also shown. The scheme is implemented in two-dimensional space on parallel computers using message passing interface (MPI). The proposed scheme with limiter features approximately 50% higher number of inter-processor message communications compared to the corresponding scheme without limiter, but with only 10% higher total CPU time. The scheme is provably second-order accurate in regions requiring positivity enforcement and higher order in the rest of domain.

Cascading second-order nonlinear processes in a lithium niobate-on-insulator microdisk.

Science.gov (United States)

Liu, Shijie; Zheng, Yuanlin; Chen, Xianfeng

2017-09-15

Whispering-gallery-mode (WGM) microcavities are very important in both fundamental science and practical applications, among which on-chip second-order nonlinear microresonators play an important role in integrated photonic functionalities. Here we demonstrate resonant second-harmonic generation (SHG) and cascaded third-harmonic generation (THG) in a lithium niobate-on-insulator (LNOI) microdisk resonator. Efficient SHG in the visible range was obtained with only several mW input powers at telecom wavelengths. THG was also observed through a cascading process, which reveals simultaneous phase matching and strong mode coupling in the resonator. Cascading of second-order nonlinear processes gives rise to an effectively large third-order nonlinearity, which makes on-chip second-order nonlinear microresonators a promising frequency converter for integrated nonlinear photonics.

Second order gauge invariant measure of a tidally deformed black hole

Energy Technology Data Exchange (ETDEWEB)

Ahmadi, Nahid, E-mail: nahmadi@ut.ac.ir [Department of Physics, University of Tehran, Kargar Avenue North, Tehran 14395-547 (Iran, Islamic Republic of)

2012-08-01

In this paper, a Lagrangian perturbation theory for the second order treatment of small disturbances of the event horizon in Schwarzchild black holes is introduced. The issue of gauge invariance in the context of general relativistic theory is also discussed. The developments of this paper is a logical continuation of the calculations presented in [1], in which the first order coordinate dependance of the intrinsic and exterinsic geometry of the horizon is examined and the first order gauge invariance of the intrinsic geometry of the horizon is shown. In context of second order perturbation theory, It is shown that the rate of the expansion of the congruence of the horizon generators is invariant under a second order reparametrization; so it can be considered as a measure of tidal perturbation. A generally non-vanishing expression for this observable, which accomodates tidal perturbations and implies nonlinear response of the horizon, is also presented.

Statistical theory of breakup reactions

International Nuclear Information System (INIS)

Bertulani, Carlos A.; Descouvemont, Pierre; Hussein, Mahir S.

2014-01-01

We propose an alternative for Coupled-Channels calculations with loosely bound exotic nuclei (CDCC), based on the the Random Matrix Model of the statistical theory of nuclear reactions. The coupled channels equations are divided into two sets. The first set, described by the CDCC, and the other set treated with RMT. The resulting theory is a Statistical CDCC (CDCC s ), able in principle to take into account many pseudo channels. (author)

Constrained generalized mechanics. The second-order case

International Nuclear Information System (INIS)

Tapia, V.

1985-01-01

The Dirac formalism for constrained systems is developed for systems described by a Lagrangian depending on up to a second-order time derivatives of the generalized co-ordinates (accelerations). It turns out that for a Lagrangian of this kind differing by a total time derivative from a Lagrangian depending on only up to first-order time-derivatives of the generalized co-ordinates (velocities), both classical mechanics at the Lagrangian level are the same; at the Hamiltonian level the two classical mechanics differ conceptually even when the solutions to both sets of Hamiltonian equations of motion are the same

Selfish punishment with avoiding mechanism can alleviate both first-order and second-order social dilemma.

Science.gov (United States)

Cui, Pengbi; Wu, Zhi-Xi

2014-11-21

Punishment, especially selfish punishment, has recently been identified as a potent promoter in sustaining or even enhancing the cooperation among unrelated individuals. However, without other key mechanisms, the first-order social dilemma and second-order social dilemma are still two enduring conundrums in biology and the social sciences even with the presence of punishment. In the present study, we investigate a spatial evolutionary four-strategy prisoner׳s dilemma game model with avoiding mechanism, where the four strategies are cooperation, defection, altruistic and selfish punishment. By introducing the low level of random mutation of strategies, we demonstrate that the presence of selfish punishment with avoiding mechanism can alleviate the two kinds of social dilemmas for various parametrizations. In addition, we propose an extended pair approximation method, whose solutions can essentially estimate the dynamical behaviors and final evolutionary frequencies of the four strategies. At last, considering the analogy between our model and the classical Lotka-Volterra system, we introduce interaction webs based on the spatial replicator dynamics and the transformed payoff matrix to qualitatively characterize the emergent co-exist strategy phases, and its validity are supported by extensive simulations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Kinetic modelling for zinc (II) ions biosorption onto Luffa cylindrica

International Nuclear Information System (INIS)

Oboh, I.; Aluyor, E.; Audu, T.

2015-01-01

The biosorption of Zinc (II) ions onto a biomaterial - Luffa cylindrica has been studied. This biomaterial was characterized by elemental analysis, surface area, pore size distribution, scanning electron microscopy, and the biomaterial before and after sorption, was characterized by Fourier Transform Infra Red (FTIR) spectrometer. The kinetic nonlinear models fitted were Pseudo-first order, Pseudo-second order and Intra-particle diffusion. A comparison of non-linear regression method in selecting the kinetic model was made. Four error functions, namely coefficient of determination (R 2 ), hybrid fractional error function (HYBRID), average relative error (ARE), and sum of the errors squared (ERRSQ), were used to predict the parameters of the kinetic models. The strength of this study is that a biomaterial with wide distribution particularly in the tropical world and which occurs as waste material could be put into effective utilization as a biosorbent to address a crucial environmental problem

Conformal maps between pseudo-Finsler spaces

Science.gov (United States)

Voicu, Nicoleta

The paper aims to initiate a systematic study of conformal mappings between Finsler spacetimes and, more generally, between pseudo-Finsler spaces. This is done by extending several results in pseudo-Riemannian geometry which are necessary for field-theoretical applications and by proposing a technique that reduces some problems involving pseudo-Finslerian conformal vector fields to their pseudo-Riemannian counterparts. Also, we point out, by constructing classes of examples, that conformal groups of flat (locally Minkowskian) pseudo-Finsler spaces can be much richer than both flat Finslerian and pseudo-Euclidean conformal groups.

Nonparametric Second-Order Theory of Error Propagation on Motion Groups.

Science.gov (United States)

Wang, Yunfeng; Chirikjian, Gregory S

2008-01-01

Error propagation on the Euclidean motion group arises in a number of areas such as in dead reckoning errors in mobile robot navigation and joint errors that accumulate from the base to the distal end of kinematic chains such as manipulators and biological macromolecules. We address error propagation in rigid-body poses in a coordinate-free way. In this paper we show how errors propagated by convolution on the Euclidean motion group, SE(3), can be approximated to second order using the theory of Lie algebras and Lie groups. We then show how errors that are small (but not so small that linearization is valid) can be propagated by a recursive formula derived here. This formula takes into account errors to second-order, whereas prior efforts only considered the first-order case. Our formulation is nonparametric in the sense that it will work for probability density functions of any form (not only Gaussians). Numerical tests demonstrate the accuracy of this second-order theory in the context of a manipulator arm and a flexible needle with bevel tip.

Large optical second-order nonlinearity of poled WO3-TeO2 glass.

Science.gov (United States)

Tanaka, K; Narazaki, A; Hirao, K

2000-02-15

Second-harmonic generation, one of the second-order nonlinear optical properties of thermally and electrically poled WO>(3)-TeO>(2) glasses, has been examined. We poled glass samples with two thicknesses (0.60 and 0.86 mm) at various temperatures to explore the effects of external electric field strength and poling temperature on second-order nonlinearity. The dependence of second-harmonic intensity on the poling temperature is maximum at a specific poling temperature. A second-order nonlinear susceptibility of 2.1 pm/V was attained for the 0.60-mm-thick glass poled at 250 degrees C. This value is fairly large compared with those for poled silica and tellurite glasses reported thus far. We speculate that the large third-order nonlinear susceptibility of WO>(3)- TeO>(2) glasses gives rise to the large second-order nonlinearity by means of a X((2)) = 3X((3)) E(dc) process.

On the second-order homogenization of wave motion in periodic media and the sound of a chessboard

Science.gov (United States)

Wautier, Antoine; Guzina, Bojan B.

2015-05-01

The goal of this study is to better understand the mathematical structure and ramifications of the second-order homogenization of low-frequency wave motion in periodic solids. To this end, multiple-scales asymptotic approach is applied to the scalar wave equation (describing anti-plane shear motion) in one and two spatial dimensions. In contrast to previous studies where the second-order homogenization has lead to the introduction of a single fourth-order derivative in the governing equation, present investigation demonstrates that such (asymptotic) approach results in a family of field equations uniting spatial, temporal, and mixed fourth-order derivatives - that jointly control incipient wave dispersion. Given the consequent freedom in selecting the affiliated lengthscale parameters, the notion of an optimal asymptotic model is next considered in a one-dimensional setting via its ability to capture the salient features of wave propagation within the first Brillouin zone, including the onset and magnitude of the phononic band gap. In the context of two-dimensional wave propagation, on the other hand, the asymptotic analysis is first established in a general setting, exposing the constant shear modulus as sufficient condition under which the second-order approximation of a bi-periodic elastic solid is both isotropic and limited to even-order derivatives. On adopting a chessboard-like periodic structure (with contrasts in both modulus and mass density) as a testbed for in-depth analytical treatment, it is next shown that the second-order approximation of germane wave motion is governed by a family fourth-order differential equations that: (i) entail exclusively even-order derivatives and homogenization coefficients that depend explicitly on the contrast in mass density; (ii) describe anisotropic wave dispersion characterized by the "sin4 θ +cos4 θ" term, and (iii) include the asymptotic model for a square lattice of circular inclusions as degenerate case. For

First- and Second-Order Full-Differential in Edge Analysis of Images

Directory of Open Access Journals (Sweden)

Dong-Mei Pu

2014-01-01

mathematics. We propose and reformulate them with a uniform definition framework. Based on our observation and analysis with the difference, we propose an algorithm to detect the edge from image. Experiments on Corel5K and PASCAL VOC 2007 are done to show the difference between the first order and the second order. After comparison with Canny operator and the proposed first-order differential, the main result is that the second-order differential has the better performance in analysis of changes of the context of images with good selection of control parameter.

Investigation and Modelling of Diesel Hydrotreating Reactions

DEFF Research Database (Denmark)

Boesen, Rasmus Risum

on a commercial CoMo catalyst, and a simple kinetic model is presented. Hydrogenation of fused aromatic rings are known to be fast, and it is possible, that the reaction rates are limited by either internal or external mass transfer. An experiment conducted at industrial temperatures and pressure, using...... naphthalene as a model compound, have shown, that intra-particle diffusion resistance are likely to limit the reaction rate. In order to produce ULSD it is necessary to remove sulfur from some of the most refrac- tive sulfur compounds, such as sterically hindered dibenzothiophenes. Basic nitrogen com- pounds...... are known to inhibit certain hydrotreating reactions. Experimental results are pre- sented, showing the effect of 3 different nitrogen compounds, acridine, 1,4-dimethylcarabazole and 3-methylindole, on the hydrodesulfurization of a real feed and of a model compound, 4,6-dimethyldibenzothiophene. It is shown...

Kinetics, equilibrium data and modeling studies for the sorption of chromium by Prosopis juliflora bark carbon

Directory of Open Access Journals (Sweden)

M. Kumar

2017-05-01

Full Text Available In this study, the activated carbon was prepared from Prosopis juliflora bark as a novel adsorbent. Removal of chromium (Cr was assessed by varying the parameters like metal concentration, temperature, pH, adsorbent dose and contact time. The feasibility of the sorption was studied using Freundlich and Langmuir isotherms including linear and non-linear regression methods. In Langmuir, various forms of linearized equations were evaluated. The isotherm parameter of dimensionless separation factor (RL was also studied. The kinetics of adsorption was studied by using Lagergren’s pseudo-first order and pseudo-second order equations and the results have shown that the adsorption process follows pseudo-second order kinetics and the adsorption process depends on both time and concentration. The mechanistic pathway of the adsorption process was evaluated with intraparticle diffusion model. The effect of heat of adsorption of the adsorbate onto the adsorbent material was determined using the thermodynamic parameters and the reusability of the adsorbent materials was ascertained with desorption studies. The adsorbent material characterization was done by using Fourier Transform Infrared Spectroscopy (FTIR, X-ray Diffraction (XRD method and morphology of the surface of adsorbent was identified with Scanning Electron Microscope (SEM.

Bloom dynamics of the genus Pseudo-nitzschia (Bacillariophyceae in two coastal bays (NW Mediterranean Sea

Directory of Open Access Journals (Sweden)

Sonia Quijano-Scheggia

2008-09-01

Full Text Available The spatial and temporal variations in the composition of Pseudo-nitzschia during bloom events from August 2005 to February 2006 were characterised in two bays of the NW Mediterranean Sea (Alfacs and Fangar Bay by means of scanning electron microscopy (SEM. The study provides detailed records of the Pseudo-nitzschia community at the species level and describes its relationship with both the surrounding environmental conditions and biotic factors such as the accompanying phytoplankton community. The size distributions of several species of Pseudo-nitzschia were monitored during the bloom events. These measurements may serve as indicators of the physiological status of the cells. The species observed in the two bays were Pseudo-nitzschia calliantha, P. delicatissima, P. fraudulenta, P. multistriata, and P. pungens. In Alfacs Bay, a mixed species bloom of P. calliantha and P. delicatissima began in late August 2005 and lasted 11 weeks. In Fangar Bay, the Pseudo-nitzschia bloom was limited to the period from early August to late September 2005 and comprised P. calliantha and P. delicatissima. Commonly, the proliferation of Pseudo-nitzschia was mono-specific or was accompanied by other diatoms. Two objectively defined groups were identified by the statistical analysis in Alfacs bay; the first was made up only of winter samples and the second of summer and autumn samples. The first group was defined by a high concentration of NO3¯ and low concentrations of NH4+, conditions associated with a high abundance of P. delicatissima and a low abundance of P. calliantha. The second group expressed the opposite characteristics. A succession of different blooming species of Pseudo-nitzschia lasting months in Alfacs Bay is described.

The Poisson equation at second order in relativistic cosmology

International Nuclear Information System (INIS)

Hidalgo, J.C.; Christopherson, Adam J.; Malik, Karim A.

2013-01-01

We calculate the relativistic constraint equation which relates the curvature perturbation to the matter density contrast at second order in cosmological perturbation theory. This relativistic ''second order Poisson equation'' is presented in a gauge where the hydrodynamical inhomogeneities coincide with their Newtonian counterparts exactly for a perfect fluid with constant equation of state. We use this constraint to introduce primordial non-Gaussianity in the density contrast in the framework of General Relativity. We then derive expressions that can be used as the initial conditions of N-body codes for structure formation which probe the observable signature of primordial non-Gaussianity in the statistics of the evolved matter density field

Regression analysis of censored data using pseudo-observations: An update

DEFF Research Database (Denmark)

Overgaard, Morten; Andersen, Per Kragh; Parner, Erik Thorlund

2015-01-01

competing risks, the restricted mean survival-time function, and the cause-specific lost-lifetime function. The pseudo-observations can be used to assess the effects of covariates on their respective functions at different times by fitting generalized linear models to the pseudo-observations. The updated...

Second-order advantage with excitation–emission photoinduced fluorimetry for the determination of the antiepileptic carbamazepine in environmental waters

International Nuclear Information System (INIS)

Lozano, Valeria A.; Escandar, Graciela M.

2013-01-01

Graphical abstract: -- Highlights: •A simple and safe method for the emerging contaminant carbamazepine is developed. •MCR-ALS algorithm allows us the quantification in very interfering media. •Determination is accomplished in natural waters using green-chemistry principles. -- Abstract: A photochemically induced fluorescence system combined with second-order chemometric analysis for the determination of the anticonvulsant carbamazepine (CBZ) is presented. CBZ is a widely used drug for the treatment of epilepsy and is included in the group of emerging contaminant present in the aquatic environment. CBZ is not fluorescent in solution but can be converted into a fluorescent compound through a photochemical reaction in a strong acid medium. The determination is carried out by measuring excitation–emission photoinduced fluorescence matrices of the products formed upon ultraviolet light irradiation in a laboratory-constructed reactor constituted by two simple 4 W germicidal tubes. Working conditions related to both the reaction medium and the photoreactor geometry are optimized by an experimental design. The developed approach enabled the determination of CBZ at trace levels without the necessity of applying separation steps, and in the presence of uncalibrated interferences which also display photoinduced fluorescence and may be potentially present in the investigated samples. Different second-order algorithms were tested and successful resolution was achieved using multivariate curve resolution-alternating least-squares (MCR-ALS). The study is employed for the discussion of the scopes and yields of each of the applied second-order chemometric tools. The quality of the proposed method is probed through the determination of the studied emerging pollutant in both environmental and drinking water samples. After a pre-concentration step on a C18 membrane using 50.0 mL of real water samples, a prediction relative error of 2% and limits of detection and

Second-order advantage with excitation–emission photoinduced fluorimetry for the determination of the antiepileptic carbamazepine in environmental waters

Energy Technology Data Exchange (ETDEWEB)

Lozano, Valeria A.; Escandar, Graciela M., E-mail: escandar@iquir-conicet.gov.ar

2013-06-11

Graphical abstract: -- Highlights: •A simple and safe method for the emerging contaminant carbamazepine is developed. •MCR-ALS algorithm allows us the quantification in very interfering media. •Determination is accomplished in natural waters using green-chemistry principles. -- Abstract: A photochemically induced fluorescence system combined with second-order chemometric analysis for the determination of the anticonvulsant carbamazepine (CBZ) is presented. CBZ is a widely used drug for the treatment of epilepsy and is included in the group of emerging contaminant present in the aquatic environment. CBZ is not fluorescent in solution but can be converted into a fluorescent compound through a photochemical reaction in a strong acid medium. The determination is carried out by measuring excitation–emission photoinduced fluorescence matrices of the products formed upon ultraviolet light irradiation in a laboratory-constructed reactor constituted by two simple 4 W germicidal tubes. Working conditions related to both the reaction medium and the photoreactor geometry are optimized by an experimental design. The developed approach enabled the determination of CBZ at trace levels without the necessity of applying separation steps, and in the presence of uncalibrated interferences which also display photoinduced fluorescence and may be potentially present in the investigated samples. Different second-order algorithms were tested and successful resolution was achieved using multivariate curve resolution-alternating least-squares (MCR-ALS). The study is employed for the discussion of the scopes and yields of each of the applied second-order chemometric tools. The quality of the proposed method is probed through the determination of the studied emerging pollutant in both environmental and drinking water samples. After a pre-concentration step on a C18 membrane using 50.0 mL of real water samples, a prediction relative error of 2% and limits of detection and

Combined First and Second Order Total Variation Inpainting using Split Bregman

KAUST Repository

Papafitsoros, Konstantinos

2013-07-12

In this article we discuss the implementation of the combined first and second order total variation inpainting that was introduced by Papafitsoros and Schdönlieb. We describe the algorithm we use (split Bregman) in detail, and we give some examples that indicate the difference between pure first and pure second order total variation inpainting.

Combined First and Second Order Total Variation Inpainting using Split Bregman

KAUST Repository

Papafitsoros, Konstantinos; Schoenlieb, Carola Bibiane; Sengul, Bati

2013-01-01

In this article we discuss the implementation of the combined first and second order total variation inpainting that was introduced by Papafitsoros and Schdönlieb. We describe the algorithm we use (split Bregman) in detail, and we give some examples that indicate the difference between pure first and pure second order total variation inpainting.

Convolution of second order linear recursive sequences II.

Directory of Open Access Journals (Sweden)

Szakács Tamás

2017-12-01

Full Text Available We continue the investigation of convolutions of second order linear recursive sequences (see the first part in [1]. In this paper, we focus on the case when the characteristic polynomials of the sequences have common root.

Second-order Data by Flow Injection Analysis with Spectrophotometric Diode-array Detection and Incorporated Gel-filtration Chromatographic Column

DEFF Research Database (Denmark)

Bechmann, Iben Ellegaard

1997-01-01

A flow injection analysis (FIA) system furnished with a gel-filtration chromatographic column and with photodiode-array detection was used for the generation of second-order data. The system presented is a model system in which the analytes are blue dextran, potassium hexacyanoferrate(III) and he......A flow injection analysis (FIA) system furnished with a gel-filtration chromatographic column and with photodiode-array detection was used for the generation of second-order data. The system presented is a model system in which the analytes are blue dextran, potassium hexacyanoferrate...

Kinetics, isotherms, and thermodynamic studies of lead, chromium, and cadmium bio-adsorption from aqueous solution onto Picea smithiana sawdust.

Science.gov (United States)

Mahmood-Ul-Hassan, Muhammad; Yasin, Muhammad; Yousra, Munazza; Ahmad, Rizwan; Sarwar, Sair

2018-05-01

Lead (Pb), chromium (Cr), and cadmium (Cd) removal capacity of sawdust (Picea smithiana) from aqueous solution was investigated by conducting batch experiments. Thermodynamic parameters, like change in standard free energy (ΔG Θ ), enthalpy (ΔH Θ ) and entropy (ΔS Θ ) during bio-adsorption process were estimated using the Van't Hoff equation. The maximum metals adsorption was observed at pH 8, 20 g L -1 bio-adsorbent and at 60 min of contact time. The metal adsorption kinetics was examined by fitting the pseudo-first-order as well as four forms of pseudo-second-order kinetic models. Type 1 pseudo-second-order equation described adsorption kinetics better than others. Langmuir model and Freundlich equations were used for calculation of sorption parameters. The Langmuir maximum adsorption capacity of Pb, Cr, and Cd was 6.35, 3.37, and 2.87 mg g -1 at room temperature, respectively. The values of the separation factor (RL) were in between 0 and 1, indicating that bio-adsorption was favorable. Thermodynamics study revealed that the Pb, Cr, and Cd uptake reactions were endothermic and spontaneous. Results of the study asserted that the removal of heavy metal ions from aqueous solution is viable and the sawdust could be used in the treatment of effluents from industries, thereby reducing the level of water pollution.

Finite difference schemes for second order systems describing black holes

International Nuclear Information System (INIS)

Motamed, Mohammad; Kreiss, H-O.; Babiuc, M.; Winicour, J.; Szilagyi, B.

2006-01-01

In the harmonic description of general relativity, the principal part of Einstein's equations reduces to 10 curved space wave equations for the components of the space-time metric. We present theorems regarding the stability of several evolution-boundary algorithms for such equations when treated in second order differential form. The theorems apply to a model black hole space-time consisting of a spacelike inner boundary excising the singularity, a timelike outer boundary and a horizon in between. These algorithms are implemented as stable, convergent numerical codes and their performance is compared in a 2-dimensional excision problem

Symmetry Classification of First Integrals for Scalar Linearizable Second-Order ODEs

Directory of Open Access Journals (Sweden)

K. S. Mahomed

2012-01-01

Full Text Available Symmetries of the fundamental first integrals for scalar second-order ordinary differential equations (ODEs which are linear or linearizable by point transformations have already been obtained. Firstly we show how one can determine the relationship between the symmetries and the first integrals of linear or linearizable scalar ODEs of order two. Secondly, a complete classification of point symmetries of first integrals of such linear ODEs is studied. As a consequence, we provide a counting theorem for the point symmetries of first integrals of scalar linearizable second-order ODEs. We show that there exists the 0-, 1-, 2-, or 3-point symmetry cases. It is shown that the maximal algebra case is unique.

Assessment of the pseudo-tracking approach for the calculation of material acceleration and pressure fields from time-resolved PIV: part I. Error propagation

Science.gov (United States)

van Gent, P. L.; Schrijer, F. F. J.; van Oudheusden, B. W.

2018-04-01

Pseudo-tracking refers to the construction of imaginary particle paths from PIV velocity fields and the subsequent estimation of the particle (material) acceleration. In view of the variety of existing and possible alternative ways to perform the pseudo-tracking method, it is not straightforward to select a suitable combination of numerical procedures for its implementation. To address this situation, this paper extends the theoretical framework for the approach. The developed theory is verified by applying various implementations of pseudo-tracking to a simulated PIV experiment. The findings of the investigations allow us to formulate the following insights and practical recommendations: (1) the velocity errors along the imaginary particle track are primarily a function of velocity measurement errors and spatial velocity gradients; (2) the particle path may best be calculated with second-order accurate numerical procedures while ensuring that the CFL condition is met; (3) least-square fitting of a first-order polynomial is a suitable method to estimate the material acceleration from the track; and (4) a suitable track length may be selected on the basis of the variation in material acceleration with track length.

A Bayesian Framework for Analysis of Pseudo-Spatial Models of Comparable Engineered Systems with Application to Spacecraft Anomaly Prediction Based on Precedent Data

Science.gov (United States)

Ndu, Obibobi Kamtochukwu

To ensure that estimates of risk and reliability inform design and resource allocation decisions in the development of complex engineering systems, early engagement in the design life cycle is necessary. An unfortunate constraint on the accuracy of such estimates at this stage of concept development is the limited amount of high fidelity design and failure information available on the actual system under development. Applying the human ability to learn from experience and augment our state of knowledge to evolve better solutions mitigates this limitation. However, the challenge lies in formalizing a methodology that takes this highly abstract, but fundamentally human cognitive, ability and extending it to the field of risk analysis while maintaining the tenets of generalization, Bayesian inference, and probabilistic risk analysis. We introduce an integrated framework for inferring the reliability, or other probabilistic measures of interest, of a new system or a conceptual variant of an existing system. Abstractly, our framework is based on learning from the performance of precedent designs and then applying the acquired knowledge, appropriately adjusted based on degree of relevance, to the inference process. This dissertation presents a method for inferring properties of the conceptual variant using a pseudo-spatial model that describes the spatial configuration of the family of systems to which the concept belongs. Through non-metric multidimensional scaling, we formulate the pseudo-spatial model based on rank-ordered subjective expert perception of design similarity between systems that elucidate the psychological space of the family. By a novel extension of Kriging methods for analysis of geospatial data to our "pseudo-space of comparable engineered systems", we develop a Bayesian inference model that allows prediction of the probabilistic measure of interest.

Second-order Cosmological Perturbations Engendered by Point-like Masses

Energy Technology Data Exchange (ETDEWEB)

Brilenkov, Ruslan [Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstrasse 25/8, A‐6020 Innsbruck (Austria); Eingorn, Maxim, E-mail: ruslan.brilenkov@gmail.com, E-mail: maxim.eingorn@gmail.com [North Carolina Central University, CREST and NASA Research Centers, 1801 Fayetteville St., Durham, NC 27707 (United States)

2017-08-20

In the ΛCDM framework, presenting nonrelativistic matter inhomogeneities as discrete massive particles, we develop the second‐order cosmological perturbation theory. Our approach relies on the weak gravitational field limit. The derived equations for the second‐order scalar, vector, and tensor metric corrections are suitable at arbitrary distances, including regions with nonlinear contrasts of the matter density. We thoroughly verify fulfillment of all Einstein equations, as well as self‐consistency of order assignments. In addition, we achieve logical positive results in the Minkowski background limit. Feasible investigations of the cosmological back-reaction manifestations by means of relativistic simulations are also outlined.

Second-order perturbations of cosmological fluids: Relativistic effects of pressure, multicomponent, curvature, and rotation

International Nuclear Information System (INIS)

Hwang, Jai-chan; Noh, Hyerim

2007-01-01

velocity perturbations including the rotation coincide with the ones in Newton's gravity. All equations in this work include the cosmological constant in the background world model. We emphasize that our relativistic/Newtonian correspondences in several situations and pure general relativistic corrections in the context of Newtonian equations are mainly about the dynamic equations of density and velocity perturbations without using the gravitational potential (metric perturbations). Consequently, our relativistic/Newtonian correspondences do not imply the absence of many space-time (i.e., pure general relativistic) effects like frame dragging, and redshift and deflection of photons even in such cases. We also present the case of multiple minimally coupled scalar fields, and properly derive the large-scale conservation properties of curvature perturbation variable in various temporal gauge conditions to the second order

Reaction-diffusion pulses: a combustion model

International Nuclear Information System (INIS)

Campos, Daniel; Llebot, Josep Enric; Fort, Joaquim

2004-01-01

We focus on a reaction-diffusion approach proposed recently for experiments on combustion processes, where the heat released by combustion follows first-order reaction kinetics. This case allows us to perform an exhaustive analytical study. Specifically, we obtain the exact expressions for the speed of the thermal pulses, their maximum temperature and the condition of self-sustenance. Finally, we propose two generalizations of the model, namely, the case of several reactants burning together, and that of time-delayed heat conduction. We find an excellent agreement between our analytical results and simulations

Reaction-diffusion pulses: a combustion model

Energy Technology Data Exchange (ETDEWEB)

Campos, Daniel [Grup de FIsica EstadIstica, Dept. de FIsica, Universitat Autonoma de Barcelona, E-08193 Bellaterrra (Spain); Llebot, Josep Enric [Grup de FIsica EstadIstica, Dept. de FIsica, Universitat Autonoma de Barcelona, E-08193 Bellaterrra (Spain); Fort, Joaquim [Dept. de FIsica, Univ. de Girona, Campus de Montilivi, 17071 Girona, Catalonia (Spain)

2004-07-02

We focus on a reaction-diffusion approach proposed recently for experiments on combustion processes, where the heat released by combustion follows first-order reaction kinetics. This case allows us to perform an exhaustive analytical study. Specifically, we obtain the exact expressions for the speed of the thermal pulses, their maximum temperature and the condition of self-sustenance. Finally, we propose two generalizations of the model, namely, the case of several reactants burning together, and that of time-delayed heat conduction. We find an excellent agreement between our analytical results and simulations.

Mixed-order phase transition in a one-dimensional model.

Science.gov (United States)

Bar, Amir; Mukamel, David

2014-01-10

We introduce and analyze an exactly soluble one-dimensional Ising model with long range interactions that exhibits a mixed-order transition, namely a phase transition in which the order parameter is discontinuous as in first order transitions while the correlation length diverges as in second order transitions. Such transitions are known to appear in a diverse classes of models that are seemingly unrelated. The model we present serves as a link between two classes of models that exhibit a mixed-order transition in one dimension, namely, spin models with a coupling constant that decays as the inverse distance squared and models of depinning transitions, thus making a step towards a unifying framework.

Effect of Second-Order Hydrodynamics on a Floating Offshore Wind Turbine

Energy Technology Data Exchange (ETDEWEB)

Roald, L.; Jonkman, J.; Robertson, A.

2014-05-01

The design of offshore floating wind turbines uses design codes that can simulate the entire coupled system behavior. At the present, most codes include only first-order hydrodynamics, which induce forces and motions varying with the same frequency as the incident waves. Effects due to second- and higher-order hydrodynamics are often ignored in the offshore industry, because the forces induced typically are smaller than the first-order forces. In this report, first- and second-order hydrodynamic analysis used in the offshore oil and gas industry is applied to two different wind turbine concepts--a spar and a tension leg platform.

Reframed Genome-Scale Metabolic Model to Facilitate Genetic Design and Integration with Expression Data.

Science.gov (United States)

Gu, Deqing; Jian, Xingxing; Zhang, Cheng; Hua, Qiang

2017-01-01

Genome-scale metabolic network models (GEMs) have played important roles in the design of genetically engineered strains and helped biologists to decipher metabolism. However, due to the complex gene-reaction relationships that exist in model systems, most algorithms have limited capabilities with respect to directly predicting accurate genetic design for metabolic engineering. In particular, methods that predict reaction knockout strategies leading to overproduction are often impractical in terms of gene manipulations. Recently, we proposed a method named logical transformation of model (LTM) to simplify the gene-reaction associations by introducing intermediate pseudo reactions, which makes it possible to generate genetic design. Here, we propose an alternative method to relieve researchers from deciphering complex gene-reactions by adding pseudo gene controlling reactions. In comparison to LTM, this new method introduces fewer pseudo reactions and generates a much smaller model system named as gModel. We showed that gModel allows two seldom reported applications: identification of minimal genomes and design of minimal cell factories within a modified OptKnock framework. In addition, gModel could be used to integrate expression data directly and improve the performance of the E-Fmin method for predicting fluxes. In conclusion, the model transformation procedure will facilitate genetic research based on GEMs, extending their applications.

THE PSEUDO-SMARANDACHE FUNCTION

OpenAIRE

David Gorski

2007-01-01

The Pseudo-Smarandache Function is part of number theory. The function comes from the Smarandache Function. The Pseudo-Smarandache Function is represented by Z(n) where n represents any natural number.

The Phase Behavior Effect on the Reaction Engineering of Transesterification Reactions and Reactor Design for Continuous Biodiesel Production

Science.gov (United States)

Csernica, Stephen N.

transitions from two phases to a single phase, or pseudo-single phase. The transition to a single phase or pseudo-single phase is a function of the methanol content. Regardless, the maximum observed reaction rate occurs at the point of the phase transition, when the concentration of triglycerides in the methanol phase is largest. The phase transition occurs due to the accumulation of the primary product, biodiesel methyl esters. Through various experiments, it was determined that the rate of the triglyceride mass transfer into the methanol phase, as well as the solubility of triglycerides in methanol, increases with increasing methyl ester concentration. Thus, there exists some critical methyl ester concentration which favors the formation of a single or pseudo-single phase system. The effect of the by-product glycerol on the reaction kinetics was also investigated. It was determined that at low methanol to triglyceride molar ratios, glycerol acts to inhibit the reaction rate and limit the overall triglyceride conversion. This occurs because glycerol accumulates in the methanol phase, i.e. the primary reaction volume. When glycerol is at relatively high concentrations within the methanol phase, triglycerides become excluded from the reaction volume. This greatly reduces the reaction rate and limits the overall conversion. As the concentration of methanol is increased, glycerol becomes diluted and the inhibitory effects become dampened. Assuming pseudo-homogeneous phase behavior, a simple kinetic model incorporating the inhibitory effects of glycerol was proposed based on batch reactor data. The kinetic model was primarily used to theoretically compare the performance of different types of continuous flow reactors for continuous biodiesel production. It was determined that the inhibitory effects of glycerol result in the requirement of very large reactor volumes when using continuous stirred tank reactors (CSTR). The reactor volume can be greatly reduced using tubular style

PID control of second-order systems with hysteresis

NARCIS (Netherlands)

Jayawardhana, Bayu; Logemann, Hartmut; Ryan, Eugene P.

2008-01-01

The efficacy of proportional, integral and derivative (PID) control for set point regulation and disturbance rejection is investigated in a context of second-order systems with hysteretic components. Two basic structures are studied: in the first, the hysteretic component resides (internally) in the

Statistical theory of breakup reactions

Energy Technology Data Exchange (ETDEWEB)

Bertulani, Carlos A., E-mail: carlos.bertulani@tamuc.edu [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce, TX (United States); Descouvemont, Pierre, E-mail: pdesc@ulb.ac.be [Physique Nucleaire Theorique et Physique Mathematique, Universite Libre de Bruxelles (ULB), Brussels (Belgium); Hussein, Mahir S., E-mail: hussein@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Estudos Avancados

2014-07-01

We propose an alternative for Coupled-Channels calculations with loosely bound exotic nuclei (CDCC), based on the the Random Matrix Model of the statistical theory of nuclear reactions. The coupled channels equations are divided into two sets. The first set, described by the CDCC, and the other set treated with RMT. The resulting theory is a Statistical CDCC (CDCC{sub s}), able in principle to take into account many pseudo channels. (author)

Adsorption of Pb(II) ions from aqueous solution by native and activated bentonite: Kinetic, equilibrium and thermodynamic study

Energy Technology Data Exchange (ETDEWEB)

Kul, Ali Riza [Yuzuncu Yil University, Faculty of Art and Science, Department of Chemistry, 65080 Van (Turkey); Koyuncu, Huelya, E-mail: hkoyuncu@yyu.edu.tr [Forensic Medicine Foundation, Felek Street No. 45, 06300 Kecioren, Ankara (Turkey)

2010-07-15

In this study, the adsorption kinetics, equilibrium and thermodynamics of Pb(II) ions on native (NB) and acid activated (AAB) bentonites were examined. The specific surface areas, pore size and pore-size distributions of the samples were fully characterized. The adsorption efficiency of Pb(II) onto the NB and AAB was increased with increasing temperature. The kinetics of adsorption of Pb(II) ions was discussed using three kinetic models, the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model. The experimental data fitted very well the pseudo-second-order kinetic model. The initial sorption rate and the activation energy were also calculated. The activation energy of the sorption was calculated as 16.51 and 13.66 kJ mol{sup -1} for NB and AAB, respectively. Experimental results were also analysed by the Langmuir, Freundlich and Dubinin-Redushkevich (D-R) isotherm equations at different temperatures. R{sub L} separation factor for Langmuir and the n value for Freundlich isotherm show that Pb(II) ions are favorably adsorbed by NB and AAB. Thermodynamic quantities such as Gibbs free energy ({Delta}G), the enthalpy ({Delta}H) and the entropy change of sorption ({Delta}S) were determined as about -5.06, 10.29 and 0.017 kJ mol{sup -1} K{sup -1}, respectively for AAB. It was shown that the sorption processes were an endothermic reactions, controlled by physical mechanisms and spontaneously.

A second order anti-diffusive Lagrange-remap scheme for two-component flows

Directory of Open Access Journals (Sweden)

Lagoutière Frédéric

2011-11-01

Full Text Available We build a non-dissipative second order algorithm for the approximate resolution of the one-dimensional Euler system of compressible gas dynamics with two components. The considered model was proposed in [1]. The algorithm is based on [8] which deals with a non-dissipative first order resolution in Lagrange-remap formalism. In the present paper we describe, in the same framework, an algorithm that is second order accurate in time and space, and that preserves sharp interfaces. Numerical results reported at the end of the paper are very encouraging, showing the interest of the second order accuracy for genuinely non-linear waves. Nous construisons un algorithme d’ordre deux et non dissipatif pour la résolution approchée des équations d’Euler de la dynamique des gaz compressibles à deux constituants en dimension un. Le modèle que nous considérons est celui à cinq équations proposé et analysé dans [1]. L’algorithme est basé sur [8] qui proposait une résolution approchée à l’ordre un et non dissipative au moyen d’un splitting de type Lagrange-projection. Dans le présent article, nous décrivons, dans le même formalisme, un algorithme d’ordre deux en temps et en espace, qui préserve des interfaces « parfaites » entre les constituants. Les résultats numériques rapportés à la fin de l’article sont très encourageants ; ils montrent clairement les avantages d’un schéma d’ordre deux pour les ondes vraiment non linéaires.

Global weighted estimates for second-order nondivergence elliptic ...

Indian Academy of Sciences (India)

Fengping Yao

2018-03-21

Mar 21, 2018 ... One of the key a priori estimates in the theory of second-order elliptic .... It is well known that the maximal functions satisfy strong p–p .... Here we prove the following auxiliary result, which will be a crucial ingredient in the proof.

Existence of solutions for second-order evolution inclusions

Directory of Open Access Journals (Sweden)

Nikolaos S. Papageorgiou

1994-01-01

Full Text Available In this paper we examine second-order nonlinear evolution inclusions and prove two existence theorems; one with a convex-valued orientor field and the other with a nonconvex-valued field. An example of a hyperbolic partial differential inclusion is also presented.

Probabilistic biosphere modeling for the long-term safety assessment of geological disposal facilities for radioactive waste using first- and second-order Monte Carlo simulation.

Science.gov (United States)

Ciecior, Willy; Röhlig, Klaus-Jürgen; Kirchner, Gerald

2018-10-01

In the present paper, deterministic as well as first- and second-order probabilistic biosphere modeling approaches are compared. Furthermore, the sensitivity of the influence of the probability distribution function shape (empirical distribution functions and fitted lognormal probability functions) representing the aleatory uncertainty (also called variability) of a radioecological model parameter as well as the role of interacting parameters are studied. Differences in the shape of the output distributions for the biosphere dose conversion factor from first-order Monte Carlo uncertainty analysis using empirical and fitted lognormal distribution functions for input parameters suggest that a lognormal approximation is possibly not always an adequate representation of the aleatory uncertainty of a radioecological parameter. Concerning the comparison of the impact of aleatory and epistemic parameter uncertainty on the biosphere dose conversion factor, the latter here is described using uncertain moments (mean, variance) while the distribution itself represents the aleatory uncertainty of the parameter. From the results obtained, the solution space of second-order Monte Carlo simulation is much larger than that from first-order Monte Carlo simulation. Therefore, the influence of epistemic uncertainty of a radioecological parameter on the output result is much larger than that one caused by its aleatory uncertainty. Parameter interactions are only of significant influence in the upper percentiles of the distribution of results as well as only in the region of the upper percentiles of the model parameters. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhancing second-order conditioning with lesions of the basolateral amygdala.

Science.gov (United States)

Holland, Peter C

2016-04-01

Because the occurrence of primary reinforcers in natural environments is relatively rare, conditioned reinforcement plays an important role in many accounts of behavior, including pathological behaviors such as the abuse of alcohol or drugs. As a result of pairing with natural or drug reinforcers, initially neutral cues acquire the ability to serve as reinforcers for subsequent learning. Accepting a major role for conditioned reinforcement in everyday learning is complicated by the often-evanescent nature of this phenomenon in the laboratory, especially when primary reinforcers are entirely absent from the test situation. Here, I found that under certain conditions, the impact of conditioned reinforcement could be extended by lesions of the basolateral amygdala (BLA). Rats received first-order Pavlovian conditioning pairings of 1 visual conditioned stimulus (CS) with food prior to receiving excitotoxic or sham lesions of the BLA, and first-order pairings of another visual CS with food after that surgery. Finally, each rat received second-order pairings of a different auditory cue with each visual first-order CS. As in prior studies, relative to sham-lesioned control rats, lesioned rats were impaired in their acquisition of second-order conditioning to the auditory cue paired with the first-order CS that was trained after surgery. However, lesioned rats showed enhanced and prolonged second-order conditioning to the auditory cue paired with the first-order CS that was trained before amygdala damage was made. Implications for an enhanced role for conditioned reinforcement by drug-related cues after drug-induced alterations in neural plasticity are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

On Application of Second Order Sliding Mode Control to Electro-Hydraulic Systems

DEFF Research Database (Denmark)