NASA Astrophysics Data System (ADS)
Plastino, A.; Rocca, M. C.
2013-11-01
We introduce here the q-Laplace transform as a new weapon in Tsallis’ arsenal, discussing its main properties and analyzing some examples. The q-Gaussian instance receives special consideration. Also, we derive the q-partition function from the q-Laplace transform.
Inversion and approximation of Laplace transforms
NASA Technical Reports Server (NTRS)
Lear, W. M.
1980-01-01
A method of inverting Laplace transforms by using a set of orthonormal functions is reported. As a byproduct of the inversion, approximation of complicated Laplace transforms by a transform with a series of simple poles along the left half plane real axis is shown. The inversion and approximation process is simple enough to be put on a programmable hand calculator.
The PROSAIC Laplace and Fourier Transform
Smith, G.A.
1994-11-01
Integral Transform methods play an extremely important role in many branches of science and engineering. The ease with which many problems may be solved using these techniques is well known. In Electrical Engineering especially, Laplace and Fourier Transforms have been used for a long time as a way to change the solution of differential equations into trivial algebraic manipulations or to provide alternate representations of signals and data. These techniques, while seemingly overshadowed by today`s emphasis on digital analysis, still form an invaluable basis in the understanding of systems and circuits. A firm grasp of the practical aspects of these subjects provides valuable conceptual tools. This tutorial paper is a review of Laplace and Fourier Transforms from an applied perspective with an emphasis on engineering applications. The interrelationship of the time and frequency domains will be stressed, in an attempt to comfort those who, after living so much of their lives in the time domain, find thinking in the frequency domain disquieting.
Generalized Laplace Transforms and Extended Heaviside Calculus
ERIC Educational Resources Information Center
Deakin, Michael A. B.
2008-01-01
An extended Heaviside calculus proposed by Peraire in a recent paper is similar to a generalization of the Laplace transform proposed by the present author. This similarity will be illustrated by analysis of an example supplied by Peraire.
An approximation for inverse Laplace transforms
NASA Technical Reports Server (NTRS)
Lear, W. M.
1981-01-01
Programmable calculator runs simple finite-series approximation for Laplace transform inversions. Utilizing family of orthonormal functions, approximation is used for wide range of transforms, including those encountered in feedback control problems. Method works well as long as F(t) decays to zero as it approaches infinity and so is appliable to most physical systems.
NASA Astrophysics Data System (ADS)
Schmitz, Gunnar; Hättig, Christof
2016-12-01
We present an implementation of pair natural orbital coupled cluster singles and doubles with perturbative triples, PNO-CCSD(T), which avoids the quasi-canonical triples approximation (T0) where couplings due to off-diagonal Fock matrix elements are neglected. A numerical Laplace transformation of the canonical expression for the perturbative (T) triples correction is used to avoid an I/O and storage bottleneck for the triples amplitudes. Results for a test set of reaction energies show that only very few Laplace grid points are needed to obtain converged energy differences and that PNO-CCSD(T) is a more robust approximation than PNO-CCSD(T0) with a reduced mean absolute deviation from canonical CCSD(T) results. We combine the PNO-based (T) triples correction with the explicitly correlated PNO-CCSD(F12*) method and investigate the use of specialized F12-PNOs in the conventional triples correction. We find that no significant additional errors are introduced and that PNO-CCSD(F12*)(T) can be applied in a black box manner.
Schmitz, Gunnar; Hättig, Christof
2016-12-21
We present an implementation of pair natural orbital coupled cluster singles and doubles with perturbative triples, PNO-CCSD(T), which avoids the quasi-canonical triples approximation (T0) where couplings due to off-diagonal Fock matrix elements are neglected. A numerical Laplace transformation of the canonical expression for the perturbative (T) triples correction is used to avoid an I/O and storage bottleneck for the triples amplitudes. Results for a test set of reaction energies show that only very few Laplace grid points are needed to obtain converged energy differences and that PNO-CCSD(T) is a more robust approximation than PNO-CCSD(T0) with a reduced mean absolute deviation from canonical CCSD(T) results. We combine the PNO-based (T) triples correction with the explicitly correlated PNO-CCSD(F12*) method and investigate the use of specialized F12-PNOs in the conventional triples correction. We find that no significant additional errors are introduced and that PNO-CCSD(F12*)(T) can be applied in a black box manner.
Numerical Laplace Transform Inversion Employing the Gaver-Stehfest Algorithm.
ERIC Educational Resources Information Center
Jacquot, Raymond G.; And Others
1985-01-01
Presents a technique for the numerical inversion of Laplace Transforms and several examples employing this technique. Limitations of the method in terms of available computer word length and the effects of these limitations on approximate inverse functions are also discussed. (JN)
Parseval-Type Relations for Laplace Transform and their Applications
ERIC Educational Resources Information Center
Herman, S.; Maceli, J.; Rogala, M.; Yurekli, O.
2008-01-01
In the present note, two Parseval-type relations involving the Laplace transform are given. The application of the relations is demonstrated in evaluating improper integrals and Laplace transforms of trigonometric functions.
NASA Astrophysics Data System (ADS)
Hohenstein, Edward G.; Parrish, Robert M.; Sherrill, C. David; Turney, Justin M.; Schaefer, Henry F.
2011-11-01
Symmetry-adapted perturbation theory (SAPT) provides a means of probing the fundamental nature of intermolecular interactions. Low-orders of SAPT (here, SAPT0) are especially attractive since they provide qualitative (sometimes quantitative) results while remaining tractable for large systems. The application of density fitting and Laplace transformation techniques to SAPT0 can significantly reduce the expense associated with these computations and make even larger systems accessible. We present new factorizations of the SAPT0 equations with density-fitted two-electron integrals and the first application of Laplace transformations of energy denominators to SAPT. The improved scalability of the DF-SAPT0 implementation allows it to be applied to systems with more than 200 atoms and 2800 basis functions. The Laplace-transformed energy denominators are compared to analogous partial Cholesky decompositions of the energy denominator tensor. Application of our new DF-SAPT0 program to the intercalation of DNA by proflavine has allowed us to determine the nature of the proflavine-DNA interaction. Overall, the proflavine-DNA interaction contains important contributions from both electrostatics and dispersion. The energetics of the intercalator interaction are are dominated by the stacking interactions (two-thirds of the total), but contain important contributions from the intercalator-backbone interactions. It is hypothesized that the geometry of the complex will be determined by the interactions of the intercalator with the backbone, because by shifting toward one side of the backbone, the intercalator can form two long hydrogen-bonding type interactions. The long-range interactions between the intercalator and the next-nearest base pairs appear to be negligible, justifying the use of truncated DNA models in computational studies of intercalation interaction energies.
Hohenstein, Edward G; Parrish, Robert M; Sherrill, C David; Turney, Justin M; Schaefer, Henry F
2011-11-07
Symmetry-adapted perturbation theory (SAPT) provides a means of probing the fundamental nature of intermolecular interactions. Low-orders of SAPT (here, SAPT0) are especially attractive since they provide qualitative (sometimes quantitative) results while remaining tractable for large systems. The application of density fitting and Laplace transformation techniques to SAPT0 can significantly reduce the expense associated with these computations and make even larger systems accessible. We present new factorizations of the SAPT0 equations with density-fitted two-electron integrals and the first application of Laplace transformations of energy denominators to SAPT. The improved scalability of the DF-SAPT0 implementation allows it to be applied to systems with more than 200 atoms and 2800 basis functions. The Laplace-transformed energy denominators are compared to analogous partial Cholesky decompositions of the energy denominator tensor. Application of our new DF-SAPT0 program to the intercalation of DNA by proflavine has allowed us to determine the nature of the proflavine-DNA interaction. Overall, the proflavine-DNA interaction contains important contributions from both electrostatics and dispersion. The energetics of the intercalator interaction are are dominated by the stacking interactions (two-thirds of the total), but contain important contributions from the intercalator-backbone interactions. It is hypothesized that the geometry of the complex will be determined by the interactions of the intercalator with the backbone, because by shifting toward one side of the backbone, the intercalator can form two long hydrogen-bonding type interactions. The long-range interactions between the intercalator and the next-nearest base pairs appear to be negligible, justifying the use of truncated DNA models in computational studies of intercalation interaction energies.
Real Variable Inversion of Laplace Transforms: An Application in Plasma Physics.
ERIC Educational Resources Information Center
Bohn, C. L.; Flynn, R. W.
1978-01-01
Discusses the nature of Laplace transform techniques and explains an alternative to them: the Widder's real inversion. To illustrate the power of this new technique, it is applied to a difficult inversion: the problem of Landau damping. (GA)
NASA Technical Reports Server (NTRS)
Truong, K. V.; Unal, Aynur; Tobak, M.
1989-01-01
Various features of the solutions of Duffing's equation are described using a representation of the solutions in the Laplace-Borel transform domain. An application of this technique is illustrated for the symmetry-breaking bifurcation of a hard spring.
An extension of the Laplace transform to Schwartz distributions
NASA Technical Reports Server (NTRS)
Price, D. R.
1974-01-01
A characterization of the Laplace transform is developed which extends the transform to the Schwartz distributions. The class of distributions includes the impulse functions and other singular functions which occur as solutions to ordinary and partial differential equations. The standard theorems on analyticity, uniqueness, and invertibility of the transform are proved by using the characterization as the definition of the Laplace transform. The definition uses sequences of linear transformations on the space of distributions which extends the Laplace transform to another class of generalized functions, the Mikusinski operators. It is shown that the sequential definition of the transform is equivalent to Schwartz' extension of the ordinary Laplace transform to distributions but, in contrast to Schwartz' definition, does not use the distributional Fourier transform. Several theorems concerning the particular linear transformations used to define the Laplace transforms are proved. All the results proved in one dimension are extended to the n-dimensional case, but proofs are presented only for those situations that require methods different from their one-dimensional analogs.
Using Expected Value to Introduce the Laplace Transform
ERIC Educational Resources Information Center
Lutzer, Carl V.
2015-01-01
We propose an introduction to the Laplace transform in which Riemann sums are used to approximate the expected net change in a function, assuming that it quantifies a process that can terminate at random. We assume only a basic understanding of probability.
Discovering the Laplace Transform in Undergraduate Differential Equations
ERIC Educational Resources Information Center
Quinn, Terrance J.; Rai, Sanjay
2008-01-01
The Laplace Transform is an object of fundamental importance in pure and applied mathematics. In addition, it has special pedagogical value in that it can provide a natural and concrete setting for a student to begin thinking about the modern concepts of "operator" and "functional". Most undergraduate textbooks, however, merely define the…
Exponentials and Laplace transforms on nonuniform time scales
NASA Astrophysics Data System (ADS)
Ortigueira, Manuel D.; Torres, Delfim F. M.; Trujillo, Juan J.
2016-10-01
We formulate a coherent approach to signals and systems theory on time scales. The two derivatives from the time-scale calculus are used, i.e., nabla (forward) and delta (backward), and the corresponding eigenfunctions, the so-called nabla and delta exponentials, computed. With these exponentials, two generalised discrete-time Laplace transforms are deduced and their properties studied. These transforms are compatible with the standard Laplace and Z transforms. They are used to study discrete-time linear systems defined by difference equations. These equations mimic the usual continuous-time equations that are uniformly approximated when the sampling interval becomes small. Impulse response and transfer function notions are introduced. This implies a unified mathematical framework that allows us to approximate the classic continuous-time case when the sampling rate is high or to obtain the standard discrete-time case, based on difference equations, when the time grid becomes uniform.
A numerical inversion of a the Laplace transform solution to radial dispersion in a porous medium.
Moench, A.F.; Ogata, A.
1981-01-01
A special form of the numerical inversion of the Laplace transform described by Stehfest (1970) is applied to the transformed solution of dispersion in a radial flow system in a porous medium. The inversion is extremely simple to use because the weighting coefficients depend only on the number of terms used in the computation and not upon the transform solution as required by most numerical inversion techniques.-from Authors
NASA Technical Reports Server (NTRS)
Chang, F.-C.; Mott, H.
1974-01-01
This paper presents a technique for the partial-fraction expansion of functions which are ratios of polynomials with real coefficients. The expansion coefficients are determined by writing the polynomials as Taylor's series and obtaining the Laurent series expansion of the function. The general formula for the inverse Laplace transform is also derived.
Membrane Operational Impedance Spectra in Chara corallina Estimated by Laplace Transforms Analysis 1
Homblé, Fabrice; Jenard, André
1986-01-01
The membrane operational impedance spectrum of Chara corallina Klein ex Willd. (R. Brown) cells is investigated using Laplace transform analysis. The spectrum changes with both amplitude and sign of the electrical stimulation when time- and voltage-dependent K+ channels contribute to the membrane conductance. We compare the advantages and disadvantage of this technique for studying membrane impedance with those of the alternating current method and the white noise method. PMID:16664925
Improved FFT-based numerical inversion of Laplace transforms via fast Hartley transform algorithm
NASA Technical Reports Server (NTRS)
Hwang, Chyi; Lu, Ming-Jeng; Shieh, Leang S.
1991-01-01
The disadvantages of numerical inversion of the Laplace transform via the conventional fast Fourier transform (FFT) are identified and an improved method is presented to remedy them. The improved method is based on introducing a new integration step length Delta(omega) = pi/mT for trapezoidal-rule approximation of the Bromwich integral, in which a new parameter, m, is introduced for controlling the accuracy of the numerical integration. Naturally, this method leads to multiple sets of complex FFT computations. A new inversion formula is derived such that N equally spaced samples of the inverse Laplace transform function can be obtained by (m/2) + 1 sets of N-point complex FFT computations or by m sets of real fast Hartley transform (FHT) computations.
NASA Technical Reports Server (NTRS)
Friedrich, R.; Drewelow, W.
1978-01-01
An algorithm is described that is based on the method of breaking the Laplace transform down into partial fractions which are then inverse-transformed separately. The sum of the resulting partial functions is the wanted time function. Any problems caused by equation system forms are largely limited by appropriate normalization using an auxiliary parameter. The practical limits of program application are reached when the degree of the denominator of the Laplace transform is seven to eight.
Fast Solvers for Transient Hydraulic Tomography based on Laplace transform
NASA Astrophysics Data System (ADS)
Bakhos, T.; Saibaba, A.; Kitanidis, P. K.
2013-12-01
Transient Hydraulic Tomography (THT) is a method to estimate the parameters hydraulic conductivity and specific storage, from measurements of hydraulic heads or pressure obtained in a series of interference tests in aquifer geologic formation such as an aquifer (i.e., pumping at one location and depth while measuring the response at several others). These measurements can be used to reconstruct the spatial variation of hydraulic parameters by solving a nonlinear inverse problem, which we tackle using the geostatistical approach. A central challenge associated with the application of the geostatistical approach to THT, is the computational cost associated with constructing the Jacobian - which represents the sensitivity of the measurements to the unknown parameters. This essentially requires repeated solutions to the 'forward problem' and the 'adjoint problem' for determination of derivatives, which are both time-dependent parabolic partial differential equations. To solve the 'forward problem', we use a Laplace Transform based exponential time integrator combined with a Krylov subspace based method for solving shifted systems. This approach allows us to independently evaluate the transient problem at different time instants at (almost) the cost of solving one steady-state groundwater equation. A similar approach can be used to accelerate the solution of the 'adjoint problem' as well. As we demonstrate, this approach dramatically lowers the computational cost associated with evaluating the Jacobian and as a result, the reconstruction of the parameters. The performance of our algorithm is demonstrated on some challenging synthetic examples; in particular, we apply it to large-scale inverse problems arising from transient hydraulic tomography.
Convergent radial dispersion: a note on evaluation of the Laplace transform solution
Moench, A.F.
1991-01-01
A numerical inversion algorithm for Laplace transforms that is capable of handling rapid changes in the computed function is applied to the Laplace transform solution to the problem of convergent radial dispersion in a homogeneous aquifer. Prior attempts by the author to invert this solution were unsuccessful for highly advective systems where the Peclet number was relatively large. The algorithm used in this note allows for rapid and accurate inversion of the solution for all Peclet numbers of practical interest, and beyond. Dimensionless breakthrough curves are illustrated for tracer input in the form of a step function, a Dirac impulse, or a rectangular input. -Author
Numerical inversion of the Laplace transform in some problems of granular media dynamics
NASA Astrophysics Data System (ADS)
Yavich, Nikolay B.
2004-04-01
Approximated value for the vertical displacement of a surface bounding a half space and a layer laying on rigid foundation filled with granular medium caused by a vertical symmetric load is received here. The results obtained for Kandaurov standard linear medium model are used. This model takes in account an internal friction. The Papoulis method of numerical inversion of the Laplace transform is applied.
Laplace transform approach for solving integral equations using computer algebra system
NASA Astrophysics Data System (ADS)
Paneva-Konovska, Jordanka; Nikolova, Yanka
2016-12-01
The Laplace transform method, along with Computer Algebra Systems (CAS) "Maple" v. 13, are extremely successfully applied for solving a class of integral equations with an arbitrary order, including fractional order integral equations. The combining of both powerful approaches allows students more quickly, enjoyable and thoroughly to master the material.
Some Half-Row Sums from Pascal's Triangle via Laplace Transforms
ERIC Educational Resources Information Center
Dence, Thomas P.
2007-01-01
This article presents some identities on the sum of the entries in the first half of a row in Pascal's triangle. The results were discovered while the author was working on a problem involving Laplace transforms, which are used in proving of the identities.
Flow to a well in a water-table aquifer: An improved laplace transform solution
Moench, A.F.
1996-01-01
An alternative Laplace transform solution for the problem, originally solved by Neuman, of constant discharge from a partially penetrating well in a water-table aquifer was obtained. The solution differs from existing solutions in that it is simpler in form and can be numerically inverted without the need for time-consuming numerical integration. The derivation invloves the use of the Laplace transform and a finite Fourier cosine series and avoids the Hankel transform used in prior derivations. The solution allows for water in the overlying unsaturated zone to be released either instantaneously in response to a declining water table as assumed by Neuman, or gradually as approximated by Boulton's convolution integral. Numerical evaluation yields results identical with results obtained by previously published methods with the advantage, under most well-aquifer configurations, of much reduced computation time.
NASA Astrophysics Data System (ADS)
Gzyl, Henryk; ter Horst, Enrique; Villasana, Minaya
2015-02-01
In a previous paper we studied a method to determine the probability density of barrier crossing times by a Brownian motion from the knowledge of its Laplace transform. This knowledge combined with the method of maximum entropy yields quite good reconstructions. The aim of this work is to extend the previous analysis in two directions. On one hand, we consider diffusions with non constant coefficients. This forces us to determine the Laplace transform numerically or by means of simulations. On the other hand, and this is the gist of this note, as numerical problems involve errors, we consider as well two possible extensions of the maximum entropy procedure which allow us to incorporate those errors into the probability reconstruction process.
Numerical Laplace transform density of states calculation for medium and large molecules
NASA Astrophysics Data System (ADS)
Romanini, D.; Lehmann, K. K.
1993-04-01
A novel implementation of the Laplace transform method for the calculation of the density of states of molecules, for which the partition function can be explicitly given is described. It consists of doing the inverse Laplace transform numerically after multiplying the integrand by a smoothing factor. This evaluation is more accurate than the method of steepest descent, and the computation can still be done on a PC in a few minutes. By first order expansion of the partition function in the anharmonic parameters we have been able to calculate the density of states for a model molecule composed by anharmonically coupled anharmonic oscillators, which cannot be treated by the well known Beyer-Swinehart algorithm.
Convergent radial dispersion: a Laplace transform solution for aquifer tracer testing
Moench, A.F.
1989-01-01
A Laplace transform solution was obtained for the injection of a tracer in a well situated in a homogeneous aquifer where steady, horizontal, radially convergent flow has been established due to pumping at a second well. The standard advection-dispersion equation for mass transfer was used as the controlling equation. For boundary conditions, mass balances that account for mixing of the tracer with the fluid residing in the injection and pumping wells were used. The derived solution, which can be adapted for either resident or flux-averaged concentration, is of practical use only for the pumped well. This problem is of interest because it is easily applied to field determination of aquifer dispersivity and effective porosity. Breakthrough curves were obtained by numerical inversion of the Laplace transform solution. -from Author
On the Analytical and Numerical Properties of the Truncated Laplace Transform
2014-05-01
In this dissertation, we construct efficient algorithms for the eval- uation of the singular value decomposition ( SVD ) of such operators. The approach...by the ONR grants #N00014-11-1-0718 and #N00014-10-1-0570 and the NSF grant #1309858. Keywords: Truncated Laplace Transform, SVD . Report Documentation...decomposition ( SVD ) of integral operators . . . . . . . . . . . . 13 2.6 Tridiagonal and five-diagonal matrices
NASA Astrophysics Data System (ADS)
Liang, Yingjie; Chen, Wen; Magin, Richard L.
2016-07-01
Analytical solutions to the fractional diffusion equation are often obtained by using Laplace and Fourier transforms, which conveniently encode the order of the time and the space derivatives (α and β) as non-integer powers of the conjugate transform variables (s, and k) for the spectral and the spatial frequencies, respectively. This study presents a new solution to the fractional diffusion equation obtained using the Laplace transform and expressed as a Fox's H-function. This result clearly illustrates the kinetics of the underlying stochastic process in terms of the Laplace spectral frequency and entropy. The spectral entropy is numerically calculated by using the direct integration method and the adaptive Gauss-Kronrod quadrature algorithm. Here, the properties of spectral entropy are investigated for the cases of sub-diffusion and super-diffusion. We find that the overall spectral entropy decreases with the increasing α and β, and that the normal or Gaussian case with α = 1 and β = 2, has the lowest spectral entropy (i.e., less information is needed to describe the state of a Gaussian process). In addition, as the neighborhood over which the entropy is calculated increases, the spectral entropy decreases, which implies a spatial averaging or coarse graining of the material properties. Consequently, the spectral entropy is shown to provide a new way to characterize the temporal correlation of anomalous diffusion. Future studies should be designed to examine changes of spectral entropy in physical, chemical and biological systems undergoing phase changes, chemical reactions and tissue regeneration.
NASA Astrophysics Data System (ADS)
Nejad, S. Mohammad Moosavi; Khanpour, Hamzeh; Tehrani, S. Atashbar; Mahdavi, Mahdi
2016-10-01
We present a detailed QCD analysis of nucleon structure functions x F3(x ,Q2) , based on Laplace transforms and the Jacobi polynomials approach. The analysis corresponds to the next-to-leading order and next-to-next-to-leading order approximations of perturbative QCD. The Laplace transform technique, as an exact analytical solution, is used for the solution of nonsinglet Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equations at low- and large-x values. The extracted results are used as input to obtain the x and Q2 evolution of x F3(x ,Q2) structure functions using the Jacobi polynomials approach. In our work, the values of the typical QCD scale ΛMS¯ (nf) and the strong coupling constant αs(MZ2) are determined for four quark flavors (nf=4 ) as well. A careful estimation of the uncertainties shall be performed using the Hessian method for the valence-quark distributions, originating from the experimental errors. We compare our valence-quark parton distribution functions sets with those of other collaborations, in particular with the CT14, MMHT14, and NNPDF sets, which are contemporary with the present analysis. The obtained results from the analysis are in good agreement with those from the literature.
Laplace transform homotopy perturbation method for the approximation of variational problems.
Filobello-Nino, U; Vazquez-Leal, H; Rashidi, M M; Sedighi, H M; Perez-Sesma, A; Sandoval-Hernandez, M; Sarmiento-Reyes, A; Contreras-Hernandez, A D; Pereyra-Diaz, D; Hoyos-Reyes, C; Jimenez-Fernandez, V M; Huerta-Chua, J; Castro-Gonzalez, F; Laguna-Camacho, J R
2016-01-01
This article proposes the application of Laplace Transform-Homotopy Perturbation Method and some of its modifications in order to find analytical approximate solutions for the linear and nonlinear differential equations which arise from some variational problems. As case study we will solve four ordinary differential equations, and we will show that the proposed solutions have good accuracy, even we will obtain an exact solution. In the sequel, we will see that the square residual error for the approximate solutions, belongs to the interval [0.001918936920, 0.06334882582], which confirms the accuracy of the proposed methods, taking into account the complexity and difficulty of variational problems.
A method extracting solar cell parameters from spectral response by inverse laplace transform
NASA Astrophysics Data System (ADS)
Tuominen, E.; Acerbis, M.; Hovinen, A.; Siirtola, T.; Sinkkonen, J.
1997-01-01
A mathematical method to interpret spectral responses measured from solar cells has been developed. Taking an inverse Laplace transform from the spectral response of a solar cell the spatial dependent collection efficiency of the cell can be obtained. Several important material parameters of the solar cell can be extracted from this function. Applying this method the properties of the solar cell can be investigated without applying characterization methods to the cell itself. We have applied the method both to simulated solar cells andto real solar cells.
NASA Astrophysics Data System (ADS)
Vatsala, Aghalaya S.; Sowmya, M.
2017-01-01
Study of nonlinear sequential fractional differential equations of Riemann-Lioville type and Caputo type initial value problem are very useful in applications. In order to develop any iterative methods to solve the nonlinear problems, we need to solve the corresponding linear problem. In this work, we develop Laplace transform method to solve the linear sequential Riemann-Liouville fractional differential equations as well as linear sequential Caputo fractional differential equations of order nq which is sequential of order q. Also, nq is chosen such that (n-1) < nq < n. All our results yield the integer results as a special case when q tends to 1.
Improvements on the minimax algorithm for the Laplace transformation of orbital energy denominators
Helmich-Paris, Benjamin Visscher, Lucas
2016-09-15
We present a robust and non-heuristic algorithm that finds all extremum points of the error distribution function of numerically Laplace-transformed orbital energy denominators. The extremum point search is one of the two key steps for finding the minimax approximation. If pre-tabulation of initial guesses is supposed to be avoided, strategies for a sufficiently robust algorithm have not been discussed so far. We compare our non-heuristic approach with a bracketing and bisection algorithm and demonstrate that 3 times less function evaluations are required altogether when applying it to typical non-relativistic and relativistic quantum chemical systems.
Axial and polar gravitational wave equations in a de Sitter expanding universe by Laplace transform
NASA Astrophysics Data System (ADS)
Viaggiu, Stefano
2017-02-01
In this paper we study the propagation in a de Sitter universe of gravitational waves generated by perturbating some unspecified spherical astrophysical object in the frequencies domain. We obtain the axial and polar perturbation equations in a cosmological de Sitter universe in the usual comoving coordinates, the coordinates we occupy in our galaxy. We write down the relevant equations in terms of Laplace transform with respect to the comoving time t instead of the usual Fourier one that is no longer available in a cosmological context. Both axial and polar perturbation equations are expressed in terms of a non trivial mixture of retarded-advanced metric coefficients with respect to the Laplace parameter s (complex translation). The axial case is studied in more detail. In particular, the axial perturbations can be reduced to a master linear second-order differential equation in terms of the Regge–Wheeler function Z where a coupling with a retarded Z with respect to the cosmological time t is present. It is shown that a de Sitter expanding universe can change the frequency ω of a gravitational wave as perceived by a comoving observer. The polar equations are much more involved. Nevertheless, we show that the polar perturbations can also be expressed in terms of four independent integrable differential equations.
Quantification in time-domain diffuse optical tomography using Mellin-Laplace transforms
Zouaoui, Judy; Di Sieno, Laura; Hervé, Lionel; Pifferi, Antonio; Farina, Andrea; Mora, Alberto Dalla; Derouard, Jacques; Dinten, Jean-Marc
2016-01-01
Simulations and phantom measurements are used to evaluate the ability of time-domain diffuse optical tomography using Mellin-Laplace transforms to quantify the absorption perturbation of centimetric objects immersed at depth 1-2 cm in turbid media. We find that the estimated absorption coefficient varies almost linearly with the absorption change in the range of 0-0.15 cm−1 but is underestimated by a factor that depends on the inclusion depth (~2, 3 and 6 for depths of 1.0, 1.5 and 2.0 cm respectively). For larger absorption changes, the variation is sublinear with ~20% decrease for δμa = 0.37 cm−1. By contrast, constraining the absorption change to the actual volume of the inclusion may considerably improve the accuracy and linearity of the reconstructed absorption. PMID:27867736
NASA Astrophysics Data System (ADS)
Malezan, A.; Tomal, A.; Antoniassi, M.; Watanabe, P. C. A.; Albino, L. D.; Poletti, M. E.
2015-11-01
In this work, a spectral reconstruction methodology for diagnostic X-ray, using Laplace inverse transform of the attenuation, was successfully applied to dental X-ray equipments. The attenuation curves of 8 commercially available dental X-ray equipment, from 3 different manufactures (Siemens, Gnatus and Dabi Atlante), were obtained by using an ionization chamber and high purity aluminium filters, while the kVp was obtained with a specific meter. A computational routine was implemented in order to adjust a model function, whose inverse Laplace transform is analytically known, to the attenuation curve. This methodology was validated by comparing the reconstructed and the measured (using semiconductor detector of cadmium telluride) spectra of a given dental X-ray unit. The spectral reconstruction showed the Dabi Atlante equipments generating similar shape spectra. This is a desirable feature from clinic standpoint because it produces similar levels of image quality and dose. We observed that equipments from Siemens and Gnatus generate significantly different spectra, suggesting that, for a given operating protocol, these units will present different levels of image quality and dose. This fact claims for the necessity of individualized operating protocols that maximize image quality and dose. The proposed methodology is suitable to perform a spectral reconstruction of dental X-ray equipments from the simple measurements of attenuation curve and kVp. The simplified experimental apparatus and the low level of technical difficulty make this methodology accessible to a broad range of users. The knowledge of the spectral distribution can help in the development of operating protocols that maximize image quality and dose.
ERIC Educational Resources Information Center
Iqbal, M.
2002-01-01
In this paper we have converted the Laplace transform into an integral equation of the first kind of convolution type, which is an ill-posed problem, and used a statistical regularization method to solve it. The method is applied to three examples. It gives a good approximation to the true solution and compares well with the method given by…
NASA Astrophysics Data System (ADS)
Mehrabi Pari, Sharareh; Javidan, Kurosh; Taghavi Shahri, Fatemeh
2016-05-01
The "Laplace Transform Method" is used to solve the Fokker-Plank equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation of nuclear suppression factor RAA. The results have good agreement with available experiment data from the PHENIX collaboration.
ERIC Educational Resources Information Center
Grimm, C. A.
This document contains two units that examine integral transforms and series expansions. In the first module, the user is expected to learn how to use the unified method presented to obtain Laplace transforms, Fourier transforms, complex Fourier series, real Fourier series, and half-range sine series for given piecewise continuous functions. In…
Helmich-Paris, Benjamin; Repisky, Michal; Visscher, Lucas
2016-07-07
We present a formulation of Laplace-transformed atomic orbital-based second-order Møller-Plesset perturbation theory (MP2) energies for two-component Hamiltonians in the Kramers-restricted formalism. This low-order scaling technique can be used to enable correlated relativistic calculations for large molecular systems. We show that the working equations to compute the relativistic MP2 energy differ by merely a change of algebra (quaternion instead of real) from their non-relativistic counterparts. With a proof-of-principle implementation we study the effect of the nuclear charge on the magnitude of half-transformed integrals and show that for light elements spin-free and spin-orbit MP2 energies are almost identical. Furthermore, we investigate the effect of separation of charge distributions on the Coulomb and exchange energy contributions, which show the same long-range decay with the inter-electronic/atomic distance as for non-relativistic MP2. A linearly scaling implementation is possible if the proper distance behavior is introduced to the quaternion Schwarz-type estimates as for non-relativistic MP2.
NASA Astrophysics Data System (ADS)
Gomez, Raul; Gomez, Sandra; Marquina, Ma. Luisa
2004-03-01
Most of the Mechanics and Mathematics for Physicists books ignore the problem of obtaining the isochrone (tautochrone) curve in the uniform gravitational field of Earth. A noticeable exception is Arfken's^1 book, which uses the Laplace transform formalism and the convolution theorem to resolve the problem. Through an adequate change of variable, the Laplace transform can be extended in such a way as to be able to apply the convolution theorem. The tautachrone problem for an arbitrary potential energy function can then be resolved. Moreover, the inverse problem of finding the potential function associated with a given arbitrary trajectory can also be established. It is worth noting that the same results can also be obtained using a less known formalism of fractional derivatives ^2. ^1G. Arfken, Mathematical Methods for Physicists. Academic Press (1970) pp 713. ^2Eduardo Flores. The tautochrone under arbitrary potentials using fractional derivatives, Am. J. Phys. 67 (1999) 718-722.
Tripathi, Rajnee; Mishra, Hradyesh Kumar
2016-01-01
In this communication, we describe the Homotopy Perturbation Method with Laplace Transform (LT-HPM), which is used to solve the Lane-Emden type differential equations. It's very difficult to solve numerically the Lane-Emden types of the differential equation. Here we implemented this method for two linear homogeneous, two linear nonhomogeneous, and four nonlinear homogeneous Lane-Emden type differential equations and use their appropriate comparisons with exact solutions. In the current study, some examples are better than other existing methods with their nearer results in the form of power series. The Laplace transform used to accelerate the convergence of power series and the results are shown in the tables and graphs which have good agreement with the other existing method in the literature. The results show that LT-HPM is very effective and easy to implement.
Bakhos, Tania; Saibaba, Arvind K.; Kitanidis, Peter K.
2015-10-15
We consider the problem of estimating parameters in large-scale weakly nonlinear inverse problems for which the underlying governing equations is a linear, time-dependent, parabolic partial differential equation. A major challenge in solving these inverse problems using Newton-type methods is the computational cost associated with solving the forward problem and with repeated construction of the Jacobian, which represents the sensitivity of the measurements to the unknown parameters. Forming the Jacobian can be prohibitively expensive because it requires repeated solutions of the forward and adjoint time-dependent parabolic partial differential equations corresponding to multiple sources and receivers. We propose an efficient method based on a Laplace transform-based exponential time integrator combined with a flexible Krylov subspace approach to solve the resulting shifted systems of equations efficiently. Our proposed solver speeds up the computation of the forward and adjoint problems, thus yielding significant speedup in total inversion time. We consider an application from Transient Hydraulic Tomography (THT), which is an imaging technique to estimate hydraulic parameters related to the subsurface from pressure measurements obtained by a series of pumping tests. The algorithms discussed are applied to a synthetic example taken from THT to demonstrate the resulting computational gains of this proposed method.
NASA Astrophysics Data System (ADS)
Khanpour, Hamzeh; Mirjalili, Abolfazl; Tehrani, S. Atashbar
2017-03-01
An analytical solution based on the Laplace transformation technique for the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations is presented at next-to-leading order accuracy in perturbative QCD. This technique is also applied to extract the analytical solution for the proton structure function, F2p(x ,Q2) , in the Laplace s space. We present the results for the separate parton distributions of all parton species, including valence quark densities, the antiquark and strange sea parton distribution functions (PDFs), and the gluon distribution. We successfully compare the obtained parton distribution functions and the proton structure function with the results from GJR08 [Gluck, Jimenez-Delgado, and Reya, Eur. Phys. J. C 53, 355 (2008)], 10.1140/epjc/s10052-007-0462-9 and KKT12 [Khanpour, Khorramian, and Tehrani, J. Phys. G 40, 045002 (2013)], 10.1088/0954-3899/40/4/045002 parametrization models as well as the x -space results using
NASA Astrophysics Data System (ADS)
Studenikin, S. A.; Golego, Nickolay; Cocivera, Michael
1998-11-01
Slow relaxation of the photoconductivity over a period of days was studied in polycrystalline ZnO and TiO2 films prepared by spray pyrolysis. The phenomenon is described by a model involving deep sensitizing hole traps in the forbidden gap. The trap state distribution based on this model was calculated using an improved Laplace transform method. For ZnO and TiO2 films, the density of states was shown to have a peak-like distribution with a maximum near the lower third of the energy gap.
Zhan, X.
2005-01-01
A parallel Fortran-MPI (Message Passing Interface) software for numerical inversion of the Laplace transform based on a Fourier series method is developed to meet the need of solving intensive computational problems involving oscillatory water level's response to hydraulic tests in a groundwater environment. The software is a parallel version of ACM (The Association for Computing Machinery) Transactions on Mathematical Software (TOMS) Algorithm 796. Running 38 test examples indicated that implementation of MPI techniques with distributed memory architecture speedups the processing and improves the efficiency. Applications to oscillatory water levels in a well during aquifer tests are presented to illustrate how this package can be applied to solve complicated environmental problems involved in differential and integral equations. The package is free and is easy to use for people with little or no previous experience in using MPI but who wish to get off to a quick start in parallel computing. ?? 2004 Elsevier Ltd. All rights reserved.
Puszka, Agathe; Hervé, Lionel; Planat-Chrétien, Anne; Koenig, Anne; Derouard, Jacques; Dinten, Jean-Marc
2013-01-01
We show how to apply the Mellin-Laplace transform to process time-resolved reflectance measurements for diffuse optical tomography. We illustrate this method on simulated signals incorporating the main sources of experimental noise and suggest how to fine-tune the method in order to detect the deepest absorbing inclusions and optimize their localization in depth, depending on the dynamic range of the measurement. To finish, we apply this method to measurements acquired with a setup including a femtosecond laser, photomultipliers and a time-correlated single photon counting board. Simulations and experiments are illustrated for a probe featuring the interfiber distance of 1.5 cm and show the potential of time-resolved techniques for imaging absorption contrast in depth with this geometry. PMID:23577292
Laplace and Z Transform Solutions of Differential and Difference Equations With the HP-41C.
ERIC Educational Resources Information Center
Harden, Richard C.; Simons, Fred O., Jr.
1983-01-01
A previously developed program for the HP-41C programmable calculator is extended to handle models of differential and difference equations with multiple eigenvalues. How to obtain difference equation solutions via the Z transform is described. (MNS)
On the Analytical and Numerical Properties of the Truncated Laplace Transform II
2015-05-29
transforms: I. singular-system analysis, Inverse Problems, 7 (1991), pp. 1–20. 25 [9] H. J. Landau and H. O. Pollak, Prolate spheroidal wave functions...Fourier analysis and uncertainty - II, Bell System Technical Journal, 40 (1961), pp. 65–84. [10] H. J. Landau and H. O. Pollak, Prolate spheroidal
NASA Astrophysics Data System (ADS)
Geslain, A.; Raetz, S.; Hiraiwa, M.; Abi Ghanem, M.; Wallen, S. P.; Khanolkar, A.; Boechler, N.; Laurent, J.; Prada, C.; Duclos, A.; Leclaire, P.; Groby, J.-P.
2016-10-01
We present a method for the recovery of complex wavenumber information via spatial Laplace transforms of spatiotemporal wave propagation measurements. The method aids in the analysis of acoustic attenuation phenomena and is applied in three different scenarios: (i) Lamb-like modes in air-saturated porous materials in the low kHz regime, where the method enables the recovery of viscoelastic parameters; (ii) Lamb modes in a Duralumin plate in the MHz regime, where the method demonstrates the effect of leakage on the splitting of the forward S1 and backward S2 modes around the Zero-Group Velocity point; and (iii) surface acoustic waves in a two-dimensional microscale granular crystal adhered to a substrate near 100 MHz, where the method reveals the complex wavenumbers for an out-of-plane translational and two in-plane translational-rotational resonances. This method provides physical insight into each system and serves as a unique tool for analyzing spatiotemporal measurements of propagating waves.
NASA Astrophysics Data System (ADS)
Kjærgaard, Thomas
2017-01-01
The divide-expand-consolidate resolution of the identity second-order Møller-Plesset perturbation (DEC-RI-MP2) theory method introduced in Baudin et al. [J. Chem. Phys. 144, 054102 (2016)] is significantly improved by introducing the Laplace transform of the orbital energy denominator in order to construct the double amplitudes directly in the local basis. Furthermore, this paper introduces the auxiliary reduction procedure, which reduces the set of the auxiliary functions employed in the individual fragments. The resulting Laplace transformed divide-expand-consolidate resolution of the identity second-order Møller-Plesset perturbation method is applied to the insulin molecule where we obtain a factor 9.5 speedup compared to the DEC-RI-MP2 method.
Schurkus, Henry F.; Ochsenfeld, Christian
2016-01-21
An atomic-orbital (AO) reformulation of the random-phase approximation (RPA) correlation energy is presented allowing to reduce the steep computational scaling to linear, so that large systems can be studied on simple desktop computers with fully numerically controlled accuracy. Our AO-RPA formulation introduces a contracted double-Laplace transform and employs the overlap-metric resolution-of-the-identity. First timings of our pilot code illustrate the reduced scaling with systems comprising up to 1262 atoms and 10 090 basis functions. .
Relaxation spectroscopy of deep levels in semiconductors: Laplace-DLTS method
NASA Astrophysics Data System (ADS)
Levin, M. N.; Bormontov, A. E.; Akhkubekov, A. É.; Tatokhin, E. A.
2010-11-01
Deep level transient spectroscopy (DLTS) is among the main methods used to determine the parameters of electrically active centers of charge localization in semiconductors. In order to increase the accuracy and adequacy of DLTS data, we propose a modified approach based on the application of an inverse Laplace transform. Using the proposed Laplace-DLTS method, it is possible to determine the parameters of centers with close carrier emission coefficients, which cannot be done using the traditional DLTS technique.
NASA Astrophysics Data System (ADS)
Li, H.; Feng, X. S.; Xiang, J.; Zuo, P.
2014-12-01
In Li et al. [2013, New approach for solving the inverse boundary value problem of Laplace's equation on a circle: Technique renovation of the Grad-Shafranov (GS) reconstruction, J. Geophys. Res. Space., 118, 2876-2881], a couple of Hilbert transform relations were applied to the study of the ill-posedness for the essential GS reconstructions. In this further study, a detailed derivation for these reciprocal relations are presented in case of the plane circular region, and then the reciprocal relations are extended to apply to the plane rectangular region after a conformal mapping procedure. While for the case of plane rectangular region, it is confronted by a traditional problem of the so-called corner singularities, which divided the extended reciprocal relations into four integrals with end-point singularities. With the help of the extended Euler-Maclaurin expansion, new quadrature schemes are developed for these singular integrals. Benchmark testing with the analytic solutions on a rectangle boundary has also show the efficiency and robustness of these extensions. The new solution approach is also developed with the introduced reciprocal relations, and an iterated Tikhonov regularization scheme is applied to deal with the ill-posed linear operators appearing in the discretization of the new approach. The special case on the rectangular boundary is benchmarked with the analytic solutions. Numerical experiments highlight the efficiency and robustness of the proposed method. A robust solution approach is expected to be developed based on these new results for the GS equation on any 2D region with partial-known boundary conditions.
The nonsinglet structure function evolution by Laplace method
Boroun, G. R. E-mail: boroun@razi.ac.ir; Zarrin, S.
2015-12-15
We derive a general scheme for the evolution of the nonsinglet structure function at the leadingorder (LO) and next-to-leading-order (NLO) by using the Laplace-transform technique. Results for the nonsinglet structure function are compared with MSTW2008, GRV, and CKMT parameterizations and also EMC experimental data in the LO and NLO analysis. The results are in good agreement with the experimental data and other parameterizations in the low- and large-x regions.
NASA Technical Reports Server (NTRS)
Pearson, E. M.; Halicioglu, T.; Tiller, W. A.
1985-01-01
A direct and convenient method is presented for deriving expressions which equate any thermodynamic state function to averages of specific dynamical functions and their fluctuations over the classical microcanonical distribution. Specific expressions are obtained for a variety of thermodynamic quantities. The effect of various entropy definitions on the results are assessed, and the latter are compared to previous work in the literature. The derived formulas are applied to the analysis of molecular-dynamics computer simulations.
NASA Astrophysics Data System (ADS)
Ebaid, Abdelhalim; Al Sharif, Mohammed A.
2015-06-01
Since the discovery of the carbon nanotubes (CNTs), there is an increasing interest in their applications in industry and medical fields. Attempts of using such CNTs as drug carriers and in cancer therapy in the presence of a magnetic field are now undertaken because of their direct impacts on increasing the thermal conductivity of base fluids. Two types of CNTs are well known for the researchers, the single-walled CNT (SWCNTs) and the multi-walled CNTs (MWCNTs); however, the subject of which one is more effective in treatment of cancer deserves more investigations. The present article discusses the effect of such types of CNTs on the flow and heat transfer of nanofluids in the presence of a magnetic field. Exact analytical solution for the heat equation has been obtained by using the Laplace transform, where the solution is expressed in terms of a new special function, the generalised incomplete gamma function. The effects of various parameters on the fluid velocity, temperature distribution, and heat transfer rates have been introduced. Details of possible applications of the current results in the treatment of cancer have been also discussed.
NASA Astrophysics Data System (ADS)
Ebaid, Abdelhalim; Wazwaz, Abdul-Majid; Alali, Elham; Masaedeh, Basem S.
2017-03-01
Very recently, it was observed that the temperature of nanofluids is finally governed by second-order ordinary differential equations with variable coefficients of exponential orders. Such coefficients were then transformed to polynomials type by using new independent variables. In this paper, a class of second-order ordinary differential equations with variable coefficients of polynomials type has been solved analytically. The analytical solution is expressed in terms of a hypergeometric function with generalized parameters. Moreover, applications of the present results have been applied on some selected nanofluids problems in the literature. The exact solutions in the literature were derived as special cases of our generalized analytical solution.
NASA Astrophysics Data System (ADS)
Hervé, Lionel; Planat-Chrétien, Anne; Di Sieno, Laura; Berger, Michel; Puszka, Agathe; Dalla Mora, Alberto; Contini, Davide; Boso, Gianluca; Dinten, Jean-Marc
2014-03-01
In order to increase sensitivity in the depth of diffusive media and to separate chromophores with distinct spectral signatures, we developed a method to process time-domain/multi-wavelength diffuse optical acquisitions: 3D Reconstructions of chromophore concentrations are performed with an algorithm based on the use of Mellin-Laplace Transform and material basis. A noise weighted data matching term is optimized by using the conjugated gradients method without expressing the Jacobian matrix of the system. As the algorithm uses reference measurements on a known medium, it does not require measurements or computations of the instrument response function of the system. Validations are performed in the reflectance geometry on a tissue-mimicking phantom composed of intralipid and black ink and a cylindrical blue dye inclusion with a radius of 4mm located at 15mm in depth. The optical tomography setup includes a laser whose picosecond pulses are injected via an optical fiber to the probed diffusive medium and the light collected by two fibers (located 15mm apart from the source), is sent to a Single-Photon Avalanche Diode (SPAD) connected to a Time-Correlated Single-Photon Counting (TCSPC) board. The source and two detectors scan the surface of the medium so as to provide 30 source-detector couples, 900 time-bins and 5 wavelength signals. 3D reconstructions performed on the black ink and blue dye materials on a mesh of around 10000 nodes show that we are able to detect, localize and determine the composition of the inclusion and the background.
Barley Transformation Using Agrobacterium-Mediated Techniques
NASA Astrophysics Data System (ADS)
Harwood, Wendy A.; Bartlett, Joanne G.; Alves, Silvia C.; Perry, Matthew; Smedley, Mark A.; Leyland, Nicola; Snape, John W.
Methods for the transformation of barley using Agrobacterium-mediated techniques have been available for the past 10 years. Agrobacterium offers a number of advantages over biolistic-mediated techniques in terms of efficiency and the quality of the transformed plants produced. This chapter describes a simple system for the transformation of barley based on the infection of immature embryos with Agrobacterium tumefaciens followed by the selection of transgenic tissue on media containing the antibiotic hygromycin. The method can lead to the production of large numbers of fertile, independent transgenic lines. It is therefore ideal for studies of gene function in a cereal crop system.
Rolling Element Bearing Fault Diagnosis Using Laplace-Wavelet Envelope Power Spectrum
NASA Astrophysics Data System (ADS)
Al-Raheem, Khalid F.; Roy, Asok; Ramachandran, K. P.; Harrison, D. K.; Grainger, Steven
2007-12-01
The bearing characteristic frequencies (BCF) contain very little energy, and are usually overwhelmed by noise and higher levels of macro-structural vibrations. They are difficult to find in their frequency spectra when using the common technique of fast fourier transforms (FFT). Therefore, Envelope Detection (ED) has always been used with FFT to identify faults occurring at the BCF. However, the computation of the ED is suffering to strictly define the resonance frequency band. In this paper, an alternative approach based on the Laplace-wavelet enveloped power spectrum is proposed. The Laplace-Wavelet shape parameters are optimized based on Kurtosis maximization criteria. The results for simulated as well as real bearing vibration signal show the effectiveness of the proposed method to extract the bearing fault characteristic frequencies from the resonant frequency band.
Benhammouda, Brahim; Vazquez-Leal, Hector
2016-01-01
This work presents an analytical solution of some nonlinear delay differential equations (DDEs) with variable delays. Such DDEs are difficult to treat numerically and cannot be solved by existing general purpose codes. A new method of steps combined with the differential transform method (DTM) is proposed as a powerful tool to solve these DDEs. This method reduces the DDEs to ordinary differential equations that are then solved by the DTM. Furthermore, we show that the solutions can be improved by Laplace-Padé resummation method. Two examples are presented to show the efficiency of the proposed technique. The main advantage of this technique is that it possesses a simple procedure based on a few straight forward steps and can be combined with any analytical method, other than the DTM, like the homotopy perturbation method.
Multiwavelet-transform-based image compression techniques
NASA Astrophysics Data System (ADS)
Rao, Sathyanarayana S.; Yoon, Sung H.; Shenoy, Deepak
1996-10-01
Multiwavelet transforms are a new class of wavelet transforms that use more than one prototype scaling function and wavelet in the multiresolution analysis/synthesis. The popular Geronimo-Hardin-Massopust multiwavelet basis functions have properties of compact support, orthogonality, and symmetry which cannot be obtained simultaneously in scalar wavelets. The performance of multiwavelets in still image compression is studied using vector quantization of multiwavelet subbands with a multiresolution codebook. The coding gain of multiwavelets is compared with that of other well-known wavelet families using performance measures such as unified coding gain. Implementation aspects of multiwavelet transforms such as pre-filtering/post-filtering and symmetric extension are also considered in the context of image compression.
Laplace's equation and Faraday's lines of force
Narasimhan, T.N.
2007-06-01
Boundary-value problems involve two dependent variables: a potential function, and a stream function. They can be approached in two mutually independent ways. The first, introduced by Laplace, involves spatial gradients at a point. Inspired by Faraday, Maxwell introduced the other, visualizing the flow domain as a collection of flow tubes and isopotential surfaces. Boundary-value problems intrinsically entail coupled treatment (or, equivalently, optimization) of potential and stream functions Historically, potential theory avoided the cumbersome optimization task through ingenious techniques such as conformal mapping and Green's functions. Laplace's point-based approach, and Maxwell's global approach, each provides its own unique insights into boundary-value problems. Commonly, Laplace's equation is solved either algebraically, or with approximate numerical methods. Maxwell's geometry-based approach opens up novel possibilities of direct optimization, providing an independent logical basis for numerical models, rather than treating them as approximate solvers of the differential equation. Whereas points, gradients, and Darcy's law are central to posing problems on the basis of Laplace's approach, flow tubes, potential differences, and the mathematical form of Ohm's law are central to posing them in natural coordinates oriented along flow paths. Besides being of philosophical interest, optimization algorithms can provide advantages that complement the power of classical numerical models. In the spirit of Maxwell, who eloquently spoke for a balance between abstract mathematical symbolism and observable attributes of concrete objects, this paper is an examination of the central ideas of the two approaches, and a reflection on how Maxwell's integral visualization may be practically put to use in a world of digital computers.
Use and Misuse of Laplace's Law in Ophthalmology
Chung, Cheuk Wang; Girard, Michaël J. A.; Jan, Ning-Jiun; Sigal, Ian A.
2016-01-01
Purpose Laplace's Law, with its compactness and simplicity, has long been employed in ophthalmology for describing the mechanics of the corneoscleral shell. We questioned the appropriateness of Laplace's Law for computing wall stress in the eye considering the advances in knowledge of ocular biomechanics. Methods In this manuscript we recapitulate the formulation of Laplace's Law, as well as common interpretations and uses in ophthalmology. Using numerical modeling, we study how Laplace's Law cannot account for important characteristics of the eye, such as variations in globe shape and size or tissue thickness, anisotropy, viscoelasticity, or that the eye is a living, dynamic organ. Results We show that accounting for various geometrical and material factors, excluded from Laplace's Law, can alter estimates of corneoscleral wall stress as much as 456% and, therefore, that Laplace's Law is unreliable. Conclusions We conclude by illustrating how computational techniques, such as finite element modeling, can account for the factors mentioned above, and are thus more suitable tools to provide quantitative characterization of corneoscleral biomechanics. PMID:26803799
The Laplace Planes of Uranus and Pluto
NASA Technical Reports Server (NTRS)
Dobrovolskis, Anthony R.
1993-01-01
Satellite orbits close to an oblate planet precess about its equatorial plane, while distant satellites precess around the plane of the planet's heliocentric orbit. In between, satellites in nearly circular orbits precess about a warped intermediate surface called the Laplace 'plane.' Herein we derive general formulas for locating the Laplace plane. Because Uranus and Pluto have high obliquities, their Laplace planes are severely warped. We present maps of these Laplace planes, of interest in telescopic searches for new satellites. The Laplace plane of the Solar System as a whole is similarly distorted, but comets in the inner Oort cloud precess too slowly to sense the Laplace plane.
Fourier transform techniques for the inference of cloud motion
NASA Technical Reports Server (NTRS)
Lo, R. C.; Rosenfeld, A.
1974-01-01
The development and evaluation are reported of phase shift techniques based on the Fourier transform for the estimation of cloud motion from geosynchronous meteorological satellite photographs. An alternative approach to cloud motion estimation, involving thresholding, was proposed and studied.
Laplace equation, magnetic recording and the Karlqvist approximation
NASA Astrophysics Data System (ADS)
Tannous, C.
2015-09-01
Magnetic recording head theory is based on the Karlqvist approximation to solve the Laplace equation over a polygonal domain that originates from a magnetostatic approach to describe the magnetic field produced by the read/write head in the recording medium. The approximation is reviewed and compared to various approaches dealing with solving the Laplace equation using different boundary conditions. The solution is obtained by the Green function, Fourier transform, Fourier series and finally by conformal mapping methods that allow us, on one hand, to comply with the Sommerfeld edge condition required at angular points and on the other, to obtain exact results.
Conformal Laplace superintegrable systems in 2D: polynomial invariant subspaces
NASA Astrophysics Data System (ADS)
Escobar-Ruiz, M. A.; Miller, Willard, Jr.
2016-07-01
2nd-order conformal superintegrable systems in n dimensions are Laplace equations on a manifold with an added scalar potential and 2n-1 independent 2nd order conformal symmetry operators. They encode all the information about Helmholtz (eigenvalue) superintegrable systems in an efficient manner: there is a 1-1 correspondence between Laplace superintegrable systems and Stäckel equivalence classes of Helmholtz superintegrable systems. In this paper we focus on superintegrable systems in two-dimensions, n = 2, where there are 44 Helmholtz systems, corresponding to 12 Laplace systems. For each Laplace equation we determine the possible two-variate polynomial subspaces that are invariant under the action of the Laplace operator, thus leading to families of polynomial eigenfunctions. We also study the behavior of the polynomial invariant subspaces under a Stäckel transform. The principal new results are the details of the polynomial variables and the conditions on parameters of the potential corresponding to polynomial solutions. The hidden gl 3-algebraic structure is exhibited for the exact and quasi-exact systems. For physically meaningful solutions, the orthogonality properties and normalizability of the polynomials are presented as well. Finally, for all Helmholtz superintegrable solvable systems we give a unified construction of one-dimensional (1D) and two-dimensional (2D) quasi-exactly solvable potentials possessing polynomial solutions, and a construction of new 2D PT-symmetric potentials is established.
An eigenvalue transformation technique for predicting drug-target interaction.
Kuang, Qifan; Xu, Xin; Li, Rong; Dong, Yongcheng; Li, Yan; Huang, Ziyan; Li, Yizhou; Li, Menglong
2015-09-09
The prediction of drug-target interactions is a key step in the drug discovery process, which serves to identify new drugs or novel targets for existing drugs. However, experimental methods for predicting drug-target interactions are expensive and time-consuming. Therefore, the in silico prediction of drug-target interactions has recently attracted increasing attention. In this study, we propose an eigenvalue transformation technique and apply this technique to two representative algorithms, the Regularized Least Squares classifier (RLS) and the semi-supervised link prediction classifier (SLP), that have been used to predict drug-target interaction. The results of computational experiments with these techniques show that algorithms including eigenvalue transformation achieved better performance on drug-target interaction prediction than did the original algorithms. These findings show that eigenvalue transformation is an efficient technique for improving the performance of methods for predicting drug-target interactions. We further show that, in theory, eigenvalue transformation can be viewed as a feature transformation on the kernel matrix. Accordingly, although we only apply this technique to two algorithms in the current study, eigenvalue transformation also has the potential to be applied to other algorithms based on kernels.
SATELLITE DYNAMICS ON THE LAPLACE SURFACE
Tremaine, Scott; Touma, Jihad; Namouni, Fathi E-mail: jihad.touma@gmail.com
2009-03-15
The orbital dynamics of most planetary satellites is governed by the quadrupole moment from the equatorial bulge of the host planet and the tidal field from the Sun. On the Laplace surface, the long-term orbital evolution driven by the combined effects of these forces is zero, so that orbits have a fixed orientation and shape. The 'classical' Laplace surface is defined for circular orbits, and coincides with the planet's equator at small planetocentric distances and with its orbital plane at large distances. A dissipative circumplanetary disk should settle to this surface, and hence satellites formed from such a disk are likely to orbit in or near the classical Laplace surface. This paper studies the properties of Laplace surfaces. Our principal results are: (1) if the planetary obliquity exceeds 68.{sup 0}875, there is a range of semimajor axes in which the classical Laplace surface is unstable; (2) at some obliquities and planetocentric distances, there is a distinct Laplace surface consisting of nested eccentric orbits, which bifurcates from the classical Laplace surface at the point where instability sets in; (3) there is also a 'polar' Laplace surface perpendicular to the line of nodes of the planetary equator on the planetary orbit; (4) for circular orbits, the polar Laplace surface is stable at small planetocentric distances and unstable at large distances; (5) at the onset of instability, this polar Laplace surface bifurcates into two polar Laplace surfaces composed of nested eccentric orbits.
Multipole Matrix of Green Function of Laplace Equation
NASA Astrophysics Data System (ADS)
Makuch, K.; Górka, P.
Multipole matrix elements of Green function of Laplace equation are calculated. The multipole matrix elements of Green function in electrostatics describe potential on a sphere which is produced by a charge distributed on the surface of a different (possibly overlapping) sphere of the same radius. The matrix elements are defined by double convolution of two spherical harmonics with the Green function of Laplace equation. The method we use relies on the fact that in the Fourier space the double convolution has simple form. Therefore we calculate the multipole matrix from its Fourier transform. An important part of our considerations is simplification of the three dimensional Fourier transformation of general multipole matrix by its rotational symmetry to the one-dimensional Hankel transformation.
CCD filter and transform techniques for interference excision
NASA Technical Reports Server (NTRS)
Borsuk, G. M.; Dewitt, R. N.
1976-01-01
The theoretical and some experimental results of a study aimed at applying CCD filter and transform techniques to the problem of interference excision within communications channels were presented. Adaptive noise (interference) suppression was achieved by the modification of received signals such that they were orthogonal to the recently measured noise field. CCD techniques were examined to develop real-time noise excision processing. They were recursive filters, circulating filter banks, transversal filter banks, an optical implementation of the chirp Z transform, and a CCD analog FFT.
Well test analysis benefits from new method of Laplace space inversion
Wooden, B.; Azari, M.; Soliman, M. )
1992-07-20
This paper reports that for modeling well test data more reliably, a new computer program easily and accurately inverts the Laplace transform. Converting real time and space solution to Laplace space is often done in the petroleum industry and provides the vehicle to develop numerous new solutions. The Laplace space transform is frequently used in pressure transient analysis primarily because it can reduce or transform a highly difficult problem into a much simpler one. Typically, a Laplace space equation can be manipulated by use of simple algebra to accomplish other desired ends, such as incorporating additional transformed equations to solve other aspects of the engineering problem. Once the transformed equation is complete, it is then necessary to convert to real time and space. This conversion is accomplished analytically by what is referred to as inverting the Laplace transform with sets of formulas and relationships between real and transformed space and time. In many cases, this inversion is not easy or cannot be done by conventional analytic means. In those situation, an engineer requires a program that numerically inverts the transform. The new program, the Azari-Wooden-Graver, or AWG method, has this capability.
Remote sensing image denoising by using discrete multiwavelet transform techniques
NASA Astrophysics Data System (ADS)
Wang, Haihui; Wang, Jun; Zhang, Jian
2006-01-01
We present a new method by using GHM discrete multiwavelet transform in image denoising on this paper. The developments in wavelet theory have given rise to the wavelet thresholding method, for extracting a signal from noisy data. The method of signal denoising via wavelet thresholding was popularized. Multiwavelets have recently been introduced and they offer simultaneous orthogonality, symmetry and short support. This property makes multiwavelets more suitable for various image processing applications, especially denoising. It is based on thresholding of multiwavelet coefficients arising from the standard scalar orthogonal wavelet transform. It takes into account the covariance structure of the transform. Denoising of images via thresholding of the multiwavelet coefficients result from preprocessing and the discrete multiwavelet transform can be carried out by treating the output in this paper. The form of the threshold is carefully formulated and is the key to the excellent results obtained in the extensive numerical simulations of image denoising. We apply the multiwavelet-based to remote sensing image denoising. Multiwavelet transform technique is rather a new method, and it has a big advantage over the other techniques that it less distorts spectral characteristics of the image denoising. The experimental results show that multiwavelet based image denoising schemes outperform wavelet based method both subjectively and objectively.
Minimax Techniques For Optimizing Non-Linear Image Algebra Transforms
NASA Astrophysics Data System (ADS)
Davidson, Jennifer L.
1989-08-01
It has been well established that the Air Force Armament Technical Laboratory (AFATL) image algebra is capable of expressing all linear transformations [7]. The embedding of the linear algebra in the image algebra makes this possible. In this paper we show a relation of the image algebra to another algebraic system called the minimax algebra. This system is used extensively in economics and operations research, but until now has not been investigated for applications to image processing. The relationship is exploited to develop new optimization methods for a class of non-linear image processing transforms. In particular, a general decomposition technique for templates in this non-linear domain is presented. Template decomposition techniques are an important tool in mapping algorithms efficiently to both sequential and massively parallel architectures.
Programmable holographic technique for implementing unitary and nonunitary transformations
NASA Astrophysics Data System (ADS)
Wang, Yu; Potoček, Václav; Barnett, Stephen M.; Feng, Xue
2017-03-01
Beyond the possibilities of linear transformations in polarization space, whose dimensionality is constrained by limited orthogonal states, we propose a technique for implementing both unitary and nonunitary transformations with higher dimensionality. Any high-dimensional matrix can be decomposed into a product of two processes realizable by utilizing spatial phase modulation and free-space propagation, in a simple, fixed, and scalable setup. Given that perfect power transmission for an arbitrary matrix may not be possible, the method is optimized to reach the theoretical best. Projected applications of the method described here include a means of restricting the infinite-dimensional Hilbert space to a finite-dimensional basis for information processing purposes, simultaneous multichannel optical routing, and a method of optical orbital angular momentum sorting and generation.
Hyperspectral imaging using the single-pixel Fourier transform technique
NASA Astrophysics Data System (ADS)
Jin, Senlin; Hui, Wangwei; Wang, Yunlong; Huang, Kaicheng; Shi, Qiushuai; Ying, Cuifeng; Liu, Dongqi; Ye, Qing; Zhou, Wenyuan; Tian, Jianguo
2017-03-01
Hyperspectral imaging technology is playing an increasingly important role in the fields of food analysis, medicine and biotechnology. To improve the speed of operation and increase the light throughput in a compact equipment structure, a Fourier transform hyperspectral imaging system based on a single-pixel technique is proposed in this study. Compared with current imaging spectrometry approaches, the proposed system has a wider spectral range (400–1100 nm), a better spectral resolution (1 nm) and requires fewer measurement data (a sample rate of 6.25%). The performance of this system was verified by its application to the non-destructive testing of potatoes.
Hyperspectral imaging using the single-pixel Fourier transform technique
Jin, Senlin; Hui, Wangwei; Wang, Yunlong; Huang, Kaicheng; Shi, Qiushuai; Ying, Cuifeng; Liu, Dongqi; Ye, Qing; Zhou, Wenyuan; Tian, Jianguo
2017-01-01
Hyperspectral imaging technology is playing an increasingly important role in the fields of food analysis, medicine and biotechnology. To improve the speed of operation and increase the light throughput in a compact equipment structure, a Fourier transform hyperspectral imaging system based on a single-pixel technique is proposed in this study. Compared with current imaging spectrometry approaches, the proposed system has a wider spectral range (400–1100 nm), a better spectral resolution (1 nm) and requires fewer measurement data (a sample rate of 6.25%). The performance of this system was verified by its application to the non-destructive testing of potatoes. PMID:28338100
Transforming Spatial Entanglement Using a Domain-Engineering Technique
NASA Astrophysics Data System (ADS)
Yu, X. Q.; Xu, P.; Xie, Z. D.; Wang, J. F.; Leng, H. Y.; Zhao, J. S.; Zhu, S. N.; Ming, N. B.
2008-12-01
We study the spatial correlation of a two-photon entangled state produced in a multistripe periodically poled LiTaO3 crystal by spontaneous parametric down-conversion. The far-field diffraction-interference experiments reveal that the transverse modulation of domain patterns transforms the spatial mode function of the two-photon state. This result offers an approach to prepare a novel type of two-photon state with a unique spatial entanglement by using a domain-engineering technique.
Alternative Shapes and Shaping Techniques for Enhanced Transformer Ratios in Beam Driven Techniques
Lemery, F.; Piot, P.
2014-01-01
The transformer ration of collinear beam-driven techniques can be significantly improved by shaping the current profile of the drive bunch. To date, several current shapes have been proposed to increase the transformer ratio and produce quasi-uniform energy loss within the drive bunch. Some of these tailoring techniques are possible as a results of recent beam-dynamics advances, e.g., transverse-to-longitudinal emittance exchanger. In ths paper, we propose an alternative class of longitudinal shapes that enable high transformer ratio and uniform energy loss across the drive bunch. We also suggest a simple method based on photocathode-laser shaping and passive shaping in wakefield structure to realize shape close to the theoretically optimized current profiles.
2010-01-01
Micropolar fluids Dipolar fluids a b s t r a c t The exact inverses of a class of Laplace transforms involving doubly-nested square roots and two branch...mechanics, for a micropolar fluid is determined. Published by Elsevier Ltd. 1. Introduction and problem formulation Using the Laplace transform, we...to the case of micropolar fluids, the theory of which was formulated by Eringen (1966). In doing so, we also extend the re- sults of Jordan et al
Cummings, Eric; LaJeunesse, Tony
2008-10-05
Laplace is a electric field driven flow simulation program for detailed device design support. Transport processes include electrokinesis, dielectrophoresis, and diffusion. Laplace solves for the electric field in a microfluidic system and the liquid and particle flow that is produced by the electric field for the primary purpose of microfluidic design development and simulation. Laplace allows you to visualize the flow by tracking tracer particles, viewing flow streamlines, etc. Laplace can make movies of simulated particle motion to allow you to test and share the behavior of microfuidic designs. The electric field is calculated using an iterative linear solver and particle motion is solved by finite difference, finite-displacement simulation of particle trajectories. Laplace uses a bitmapped picture or drawing of a microsystem to infer the geometry. The channel depth is everywhere proportional to the magnitude of the blue channel of the image: 0 (black) = zero depth, or no channel, 256 (saturated blue) = deepest channel, and intermediate values correspond to intermediate depths. Laplace automatically applies various boundary conditions (applied voltage or current) to ports, where channels cross the edge of the image.
Robust watermark technique using masking and Hermite transform.
Coronel, Sandra L Gomez; Ramírez, Boris Escalante; Mosqueda, Marco A Acevedo
2016-01-01
The following paper evaluates a watermark algorithm designed for digital images by using a perceptive mask and a normalization process, thus preventing human eye detection, as well as ensuring its robustness against common processing and geometric attacks. The Hermite transform is employed because it allows a perfect reconstruction of the image, while incorporating human visual system properties; moreover, it is based on the Gaussian functions derivates. The applied watermark represents information of the digital image proprietor. The extraction process is blind, because it does not require the original image. The following techniques were utilized in the evaluation of the algorithm: peak signal-to-noise ratio, the structural similarity index average, the normalized crossed correlation, and bit error rate. Several watermark extraction tests were performed, with against geometric and common processing attacks. It allowed us to identify how many bits in the watermark can be modified for its adequate extraction.
Laplace domain automatic data assimilation of contaminant transport using a Wireless Sensor Network
NASA Astrophysics Data System (ADS)
Barnhart, K.; Illangasekare, T. H.
2011-12-01
Emerging in situ sensors and distributed network technologies have the potential to monitor dynamic hydrological and environmental processes more effectively than traditional monitoring and data acquisition techniques by sampling at greater spatial and temporal resolutions. In particular, Wireless Sensor Networks, the combination of low-power telemetry and energy-harvesting with miniaturized sensors, could play a large role in monitoring the environment on nature's time scale. Since sensor networks supply data with little or no delay, applications exist where automatic or real-time assimilation of this data would be useful, for example during smart remediation procedures where tracking of the plume response will reinforce real-time decisions. As a foray into this new data context, we consider the estimation of hydraulic conductivity when incorporating subsurface plume concentration data. Current practice optimizes the model in the time domain, which is often slow and overly sensitive to data anomalies. Instead, we perform model inversion in Laplace space and are able to do so because data gathered using new technologies can be sampled densely in time. An intermediate-scale synthetic aquifer is used to illustrate the developed technique. Data collection and model (re-)optimization are automatic. Electric conductivity values of passing sodium bromide plumes are sent through a wireless sensor network, stored in a database, scrubbed and passed to a modeling server which transforms the data and assimilates it into a Laplace domain model. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000
Improved technique for one-way transformation of information
Cooper, J.A.
1987-05-11
Method and apparatus are provided for one-way transformation of data according to multiplication and/or exponentiation modulo a prime number. An implementation of the invention permits the one way residue transformation, useful in encryption and similar applications, to be implemented by n-bit computers substantially with no increase in difficulty or complexity over a natural transformation thereby, using a modulus which is a power of two. 9 figs.
Dessouky, Mohamed M; Elrashidy, Mohamed A; Taha, Taha E; Abdelkader, Hatem M
2016-05-01
The different discrete transform techniques such as discrete cosine transform (DCT), discrete sine transform (DST), discrete wavelet transform (DWT), and mel-scale frequency cepstral coefficients (MFCCs) are powerful feature extraction techniques. This article presents a proposed computer-aided diagnosis (CAD) system for extracting the most effective and significant features of Alzheimer's disease (AD) using these different discrete transform techniques and MFCC techniques. Linear support vector machine has been used as a classifier in this article. Experimental results conclude that the proposed CAD system using MFCC technique for AD recognition has a great improvement for the system performance with small number of significant extracted features, as compared with the CAD system based on DCT, DST, DWT, and the hybrid combination methods of the different transform techniques.
Laplace, Pierre-Simon (1749-1827)
NASA Astrophysics Data System (ADS)
Murdin, P.
2000-11-01
Celestial mechanician, born in Beaumont-en-Auge, Normandy, France, became professor of mathematics at the Ecole Militaire in Paris, examining the cadet Napoleon Bonaparte. This position made Laplace well known to people in positions of power, which he opportunistically exploited, becoming, under Napoleon, Minister of the Interior (Napoleon soon removed him from office `because he brought the spir...
Evaluation of the Laplace Integral. Classroom Notes
ERIC Educational Resources Information Center
Chen, Hongwei
2004-01-01
Based on the dominated convergence theorem and parametric differentiation, two different evaluations of the Laplace integral are displayed. This article presents two different proofs of (1) which may be of interest since they are based on principles within the realm of real analysis. The first method applies the dominated convergence theorem to…
Embedded wavelet packet transform technique for texture compression
NASA Astrophysics Data System (ADS)
Li, Jin; Cheng, Po-Yuen; Kuo, C.-C. Jay
1995-09-01
A highly efficient texture compression scheme is proposed in this research. With this scheme, energy compaction of texture images is first achieved by the wavelet packet transform, and an embedding approach is then adopted for the coding of the wavelet packet transform coefficients. By comparing the proposed algorithm with the JPEG standard, FBI wavelet/scalar quantization standard and the EZW scheme with extensive experimental results, we observe a significant improvement in the rate-distortion performance and visual quality.
Experiments on Active Cloaking and Illusion for Laplace Equation
NASA Astrophysics Data System (ADS)
Ma, Qian; Mei, Zhong Lei; Zhu, Shou Kui; Jin, Tian Yu; Cui, Tie Jun
2013-10-01
In recent years, invisibility cloaks have received a lot of attention and interest. These devices are generally classified into two types: passive and active. The design and realization of passive cloaks have been intensively studied using transformation optics and plasmonic approaches. However, active cloaks are still limited to theory and numerical simulations. Here, we present the first experiment on active cloaking and propose an active illusion for the Laplace equation. We make use of a resistor network to simulate a conducting medium. Then, we surround the central region with controlled sources to protect it from outside detection. We show that by dynamically changing the controlled sources, the protected region can be cloaked or disguised as different objects (illusion). Our measurement results agree very well with numerical simulations. Compared with the passive counterparts, the active cloaking and illusion devices do not need complicated metamaterials. They are flexible, in-line controllable, and adaptable to the environment. In addition to dc electricity, the proposed method can also be used for thermodynamics and other problems governed by the Laplace equation.
Yang, Jiao-lan; Luo, Tian
2002-08-01
This paper expatriated the applications for Fourier transform infrared spectrum analysis technique in preventive medicine field from four aspects of environmental pollution, life science, and the latest infrared analysis methods and near infrared analysis technique. In the environmental pollution field, it mainly described the advantages, the limitations and the solutions of the combined applications for gas chromatograph and Fourier transform infrared spectrum. In the life science field, it described the application for Fourier transform infrared spectrum analysis technique on protein secondary structure, membrane protein, phospholipid, nucleic acid, cell, tissue. In addition, it also introduced a few latest infrared analysis methods and the applications for near infrared spectrum analysis technique in food, cosmetic, drug.
The resurrection of Laplace's method of initial orbit determination
NASA Astrophysics Data System (ADS)
Taff, L. G.
1983-01-01
This report deals with a number of interrelated topics. The common thread is Laplace's method of initial orbit determination based on passively acquired optical data. We discuss this method's principal competitor (that of Gauss), the difficulties of Gauss's technique, and the traditional reasons the Gaussian method is preferred to the Laplacian. We reject this hegemony for a variety of reasons and concentrate on Laplace's method in an era of a surfeit of high quality data. This leads us into a discussion of data smoothing. Once one leaves the raw observatorial data the possibility of combining observations from multiple observers comes to mind and hence the determination of parallax by trigonometrical means. All of this may be applied to two different classes of objects-astroids and artificial satellites. Our immediate interests are in fast moving asteroids (greater than 0.5/day or an abnormally fast ecliptic latitude rate) and high altitude artificial satellites (P greater than 6h). In both instances it is the high inclination and high eccentricity subset which is of special concern.
NASA Technical Reports Server (NTRS)
Morris, A. Terry
1999-01-01
This paper examines various sources of error in MIT's improved top oil temperature rise over ambient temperature model and estimation process. The sources of error are the current parameter estimation technique, quantization noise, and post-processing of the transformer data. Results from this paper will show that an output error parameter estimation technique should be selected to replace the current least squares estimation technique. The output error technique obtained accurate predictions of transformer behavior, revealed the best error covariance, obtained consistent parameter estimates, and provided for valid and sensible parameters. This paper will also show that the output error technique should be used to minimize errors attributed to post-processing (decimation) of the transformer data. Models used in this paper are validated using data from a large transformer in service.
Wavelet-based denoising using local Laplace prior
NASA Astrophysics Data System (ADS)
Rabbani, Hossein; Vafadust, Mansur; Selesnick, Ivan
2007-09-01
Although wavelet-based image denoising is a powerful tool for image processing applications, relatively few publications have addressed so far wavelet-based video denoising. The main reason is that the standard 3-D data transforms do not provide useful representations with good energy compaction property, for most video data. For example, the multi-dimensional standard separable discrete wavelet transform (M-D DWT) mixes orientations and motions in its subbands, and produces the checkerboard artifacts. So, instead of M-D DWT, usually oriented transforms suchas multi-dimensional complex wavelet transform (M-D DCWT) are proposed for video processing. In this paper we use a Laplace distribution with local variance to model the statistical properties of noise-free wavelet coefficients. This distribution is able to simultaneously model the heavy-tailed and intrascale dependency properties of wavelets. Using this model, simple shrinkage functions are obtained employing maximum a posteriori (MAP) and minimum mean squared error (MMSE) estimators. These shrinkage functions are proposed for video denoising in DCWT domain. The simulation results shows that this simple denoising method has impressive performance visually and quantitatively.
Fourier transform infrared spectroscopy as a surface science technique
NASA Astrophysics Data System (ADS)
Celio, Hugo; Trenary, Michael
1998-06-01
A central goal of modern surface science is to obtain atomic and molecular level information about the structural and chemical properties of solid surfaces. For many, if not most, problems in surface science it is necessary to work under ultra high vacuum (UHV) conditions to obtain meaningful and reproducible results. A wide array of highly specialized and hence expensive UHV surface sensitive techniques have been developed to probe the gas-solid interface. Most of these techniques rely on the finite penetration depth of charge particles to achieve surface sensitivity. In contrast, surface sensitivity can also be achieved with reflection absorption infrared spectroscopy using unmodified low-cost commercial FTIR spectrometers. In this paper we show how a variety of problems in surface chemistry can be effectively addressed with FTIR spectroscopy.
NASA Astrophysics Data System (ADS)
Petrov, P.; Newman, G. A.
2011-12-01
Recent developments in high resolution imaging technology of subsurface objects involves a combination of different geophysical measurements (gravity, EM and seismic). A joint image of the subsurface geophysical attributes (velocity, electrical conductivity and density) requires the consistent treatment of the different geophysical data due to their differing physical nature. For example, in conducting media, which is typical of the Earth's interior, EM energy propagation is defined by a diffusive mechanism and may be characterized by two specific length scales: wavelength and skin depth. However, the propagation of seismic signals is a multiwave process and is characterized by a set of wavelengths. Thus, to consistently treat seismic and electromagnetic data an additional length scale is needed for seismic data that does not directly depend on a wavelength and describes a diffusive process, similar to EM wave propagation in the subsurface. Works by Brown et al.(2005), Shin and Cha(2008), and Shin and Ha(2008) suggest that an artificial damping of seismic wave fields via Laplace-Fourier transformation can be an effective approach to obtain a seismic data that have similar spatial resolution to EM data. The key benefit of such transformation is that diffusive wave-field inversion works well for both data sets: seismic (Brown et al.,2005; Shin and Cha,2008) and electromagnetic (Commer and Newman,2008; Newman et al.,2010). With the recent interest in the Laplace-Fourier domain full waveform inversion, 3D fourth and second-order finite-difference schemes for modeling of seismic wave propagation have been developed (Petrov and Newman, 2010). Incorporation of attenuation and anisotropy into a velocity model is a necessary step for a more realistic description of subsurface media. Here we consider the extension of our method which includes attenuation and VTI anisotropy. Our approach is based on the integro-interpolation technique for velocity-stress formulation. Seven
Solving nonlinear or stiff differential equations by Laplace homotopy analysis method(LHAM)
NASA Astrophysics Data System (ADS)
Chong, Fook Seng; Lem, Kong Hoong; Wong, Hui Lin
2015-10-01
The initial value problems of nonlinear or stiff ordinary differential equation appear in many fields of engineering science, particularly in the studies of electrical circuits, chemical reactions, wave vibration and so on. In this research, the standard homotopy analysis method hybrids with Laplace transform method to solve nonlinear and stiff differential equations. Using this modification, the problems solved by LHAM successfully yield good solutions. Some examples are examined to highlight the convenience and effectiveness of LHAM.
Incipient fault diagnosis of power transformers using optical spectro-photometric technique
NASA Astrophysics Data System (ADS)
Hussain, K.; Karmakar, Subrata
2015-06-01
Power transformers are the vital equipment in the network of power generation, transmission and distribution. Mineral oil in oil-filled transformers plays very important role as far as electrical insulation for the winding and cooling of the transformer is concerned. As transformers are always under the influence of electrical and thermal stresses, incipient faults like partial discharge, sparking and arcing take place. As a result, mineral oil deteriorates there by premature failure of the transformer occurs causing huge losses in terms of revenue and assets. Therefore, the transformer health condition has to be monitored continuously. The Dissolved Gas Analysis (DGA) is being extensively used for this purpose, but it has some drawbacks like it needs carrier gas, regular instrument calibration, etc. To overcome these drawbacks, Ultraviolet (UV) -Visible and Fourier Transform Infrared (FTIR) Spectro-photometric techniques are used as diagnostic tools for investigating the degraded transformer oil affected by electrical, mechanical and thermal stresses. The technique has several advantages over the conventional DGA technique.
Illias, Hazlee Azil; Chai, Xin Rui; Abu Bakar, Ab Halim; Mokhlis, Hazlie
2015-01-01
It is important to predict the incipient fault in transformer oil accurately so that the maintenance of transformer oil can be performed correctly, reducing the cost of maintenance and minimise the error. Dissolved gas analysis (DGA) has been widely used to predict the incipient fault in power transformers. However, sometimes the existing DGA methods yield inaccurate prediction of the incipient fault in transformer oil because each method is only suitable for certain conditions. Many previous works have reported on the use of intelligence methods to predict the transformer faults. However, it is believed that the accuracy of the previously proposed methods can still be improved. Since artificial neural network (ANN) and particle swarm optimisation (PSO) techniques have never been used in the previously reported work, this work proposes a combination of ANN and various PSO techniques to predict the transformer incipient fault. The advantages of PSO are simplicity and easy implementation. The effectiveness of various PSO techniques in combination with ANN is validated by comparison with the results from the actual fault diagnosis, an existing diagnosis method and ANN alone. Comparison of the results from the proposed methods with the previously reported work was also performed to show the improvement of the proposed methods. It was found that the proposed ANN-Evolutionary PSO method yields the highest percentage of correct identification for transformer fault type than the existing diagnosis method and previously reported works.
2015-01-01
It is important to predict the incipient fault in transformer oil accurately so that the maintenance of transformer oil can be performed correctly, reducing the cost of maintenance and minimise the error. Dissolved gas analysis (DGA) has been widely used to predict the incipient fault in power transformers. However, sometimes the existing DGA methods yield inaccurate prediction of the incipient fault in transformer oil because each method is only suitable for certain conditions. Many previous works have reported on the use of intelligence methods to predict the transformer faults. However, it is believed that the accuracy of the previously proposed methods can still be improved. Since artificial neural network (ANN) and particle swarm optimisation (PSO) techniques have never been used in the previously reported work, this work proposes a combination of ANN and various PSO techniques to predict the transformer incipient fault. The advantages of PSO are simplicity and easy implementation. The effectiveness of various PSO techniques in combination with ANN is validated by comparison with the results from the actual fault diagnosis, an existing diagnosis method and ANN alone. Comparison of the results from the proposed methods with the previously reported work was also performed to show the improvement of the proposed methods. It was found that the proposed ANN-Evolutionary PSO method yields the highest percentage of correct identification for transformer fault type than the existing diagnosis method and previously reported works. PMID:26103634
Feeling Wall Tension in an Interactive Demonstration of Laplace's Law
ERIC Educational Resources Information Center
Letic, Milorad
2012-01-01
Laplace's Law plays a major role in explanations of the wall tension of structures like blood vessels, the bladder, the uterus in pregnancy, bronchioles, eyeballs, and the behavior of aneurisms or the enlarged heart. The general relation of Laplace's law, expressing that the product of the radius of curvature (r) and pressure (P) is equal to wall…
Towards Informetrics: Haitun, Laplace, Zipf, Bradford and the Alvey Programme.
ERIC Educational Resources Information Center
Brookes, B. C.
1984-01-01
Review of recent developments in statistical theories for social sciences highlights Haitun's statistical distributions, Laplace's "Law of Succession" and distribution, Laplace and Bradford analysis of book-index data, inefficiency of frequency distribution analysis, Laws of Bradford and Zipf, natural categorization, and Bradford Law and…
Miller, Robert; Plessow, Franziska
2013-06-01
Endocrine time series often lack normality and homoscedasticity most likely due to the non-linear dynamics of their natural determinants and the immanent characteristics of the biochemical analysis tools, respectively. As a consequence, data transformation (e.g., log-transformation) is frequently applied to enable general linear model-based analyses. However, to date, data transformation techniques substantially vary across studies and the question of which is the optimum power transformation remains to be addressed. The present report aims to provide a common solution for the analysis of endocrine time series by systematically comparing different power transformations with regard to their impact on data normality and homoscedasticity. For this, a variety of power transformations of the Box-Cox family were applied to salivary cortisol data of 309 healthy participants sampled in temporal proximity to a psychosocial stressor (the Trier Social Stress Test). Whereas our analyses show that un- as well as log-transformed data are inferior in terms of meeting normality and homoscedasticity, they also provide optimum transformations for both, cross-sectional cortisol samples reflecting the distributional concentration equilibrium and longitudinal cortisol time series comprising systematically altered hormone distributions that result from simultaneously elicited pulsatile change and continuous elimination processes. Considering these dynamics of endocrine oscillations, data transformation prior to testing GLMs seems mandatory to minimize biased results.
Highly efficient manipulation of Laplace fields in film system with structured bilayer composite.
Lan, Chuwen; Lei, Ming; Bi, Ke; Li, Bo; Zhou, Ji
2016-12-26
Using metamaterials or transformation optics to manipulate Laplace fields, such as magnetic, electric and thermal fields, has become a research highlight. These studies, however, are usually limited to a bulk material system and to single field manipulation. In this paper, we focus on a film system and propose a general practical method applicable for such a system. In this method, the background film is covered with another one to construct a so-called "bilayer composite" to achieve required physical parameters. On the basis of the bilayer composite, a multi-physics cloak and a multi-physics concentrator for electric current and thermal flux are designed, fabricated, and demonstrated. This work provides an efficient way to control and manipulate single/ multi-physics Laplace fields like a dc electric field and a thermal field in a film system, which may find potential applications in IC technology, MEMS, and so on.
Myocardial wall thickening from gated magnetic resonance images using Laplace's equation
NASA Astrophysics Data System (ADS)
Prasad, M.; Ramesh, A.; Kavanagh, P.; Gerlach, J.; Germano, G.; Berman, D. S.; Slomka, P. J.
2009-02-01
The aim of our work is to present a robust 3D automated method for measuring regional myocardial thickening using cardiac magnetic resonance imaging (MRI) based on Laplace's equation. Multiple slices of the myocardium in short-axis orientation at end-diastolic and end-systolic phases were considered for this analysis. Automatically assigned 3D epicardial and endocardial boundaries were fitted to short-axis and long axis slices corrected for breathold related misregistration, and final boundaries were edited by a cardiologist if required. Myocardial thickness was quantified at the two cardiac phases by computing the distances between the myocardial boundaries over the entire volume using Laplace's equation. The distance between the surfaces was found by computing normalized gradients that form a vector field. The vector fields represent tangent vectors along field lines connecting both boundaries. 3D thickening measurements were transformed into polar map representation and 17-segment model (American Heart Association) regional thickening values were derived. The thickening results were then compared with standard 17-segment 6-point visual scoring of wall motion/wall thickening (0=normal; 5=greatest abnormality) performed by a consensus of two experienced imaging cardiologists. Preliminary results on eight subjects indicated a strong negative correlation (r=-0.8, p<0.0001) between the average thickening obtained using Laplace and the summed segmental visual scores. Additionally, quantitative ejection fraction measurements also correlated well with average thickening scores (r=0.72, p<0.0001). For segmental analysis, we obtained an overall correlation of -0.55 (p<0.0001) with higher agreement along the mid and apical regions (r=-0.6). In conclusion 3D Laplace transform can be used to quantify myocardial thickening in 3D.
Correlation Filtering of Modal Dynamics using the Laplace Wavelet
NASA Technical Reports Server (NTRS)
Freudinger, Lawrence C.; Lind, Rick; Brenner, Martin J.
1997-01-01
Wavelet analysis allows processing of transient response data commonly encountered in vibration health monitoring tasks such as aircraft flutter testing. The Laplace wavelet is formulated as an impulse response of a single mode system to be similar to data features commonly encountered in these health monitoring tasks. A correlation filtering approach is introduced using the Laplace wavelet to decompose a signal into impulse responses of single mode subsystems. Applications using responses from flutter testing of aeroelastic systems demonstrate modal parameters and stability estimates can be estimated by correlation filtering free decay data with a set of Laplace wavelets.
Computer-Assisted Techniques to Enhance Transformative Learning in First-Year Literature Courses.
ERIC Educational Resources Information Center
Jamieson, Marguerite; Kajs, Rebecca; Agee, Anne
1996-01-01
Illustrates techniques to foster transformative learning in computer-assisted literature classes: (1) a lesson plan on John Donne's "A Valediction: Forbidding Mourning"; (2) a plan to analyze "Oedipus Rex" using the "Daedalus" Interactive Writing Environment; and (3) a demonstration of how students engage in "meta-reflection" as they explore…
Multispectral image sharpening using wavelet transform techniques and spatial correlation of edges
Lemeshewsky, George P.; Schowengerdt, Robert A.
2000-01-01
Several reported image fusion or sharpening techniques are based on the discrete wavelet transform (DWT). The technique described here uses a pixel-based maximum selection rule to combine respective transform coefficients of lower spatial resolution near-infrared (NIR) and higher spatial resolution panchromatic (pan) imagery to produce a sharpened NIR image. Sharpening assumes a radiometric correlation between the spectral band images. However, there can be poor correlation, including edge contrast reversals (e.g., at soil-vegetation boundaries), between the fused images and, consequently, degraded performance. To improve sharpening, a local area-based correlation technique originally reported for edge comparison with image pyramid fusion is modified for application with the DWT process. Further improvements are obtained by using redundant, shift-invariant implementation of the DWT. Example images demonstrate the improvements in NIR image sharpening with higher resolution pan imagery.
Convergence rate of Cesaro means of Fourier-Laplace series
NASA Astrophysics Data System (ADS)
Li, Luoqing; Yu, Chunwu
2007-01-01
The convergence rate of Fourier-Laplace series in logarithmic subclasses of L2([Sigma]d) defined in terms of moduli of continuity is of interest. Lin and Wang [C. Lin, K. Wang, Convergence rate of Fourier-Laplace series of L2-functions, J. Approx. Theory 128 (2004) 103-114] recently presented a characterization of those subclasses and provided the almost everywhere convergence rates of Fourier-Laplace series in those subclasses. In this note, the almost everywhere convergence rates of the Cesaro means for Fourier-Laplace series of the logarithmic subclasses are obtained. The strong approximation order of the Cesaro means and the partial summation operators are also presented.
Novel combinatorial probabilistic Hough transform technique for detection of underwater bubbles
NASA Astrophysics Data System (ADS)
Goulermas, John Y.; Liatsis, Panos
1997-04-01
Combinatorial Probabilistic Hough Transforms (CPHTs) are a class of HTs that transform minimal subsets of points required to define an instance of the sought shape to single parameter cells, thus reducing redundant evidence. Existing CPHTs discard valuable information contained in the gradient of the object outlines. This research proposes a novel HT technique for detection of circular instances, called the C2PHT. The concept of the C2PHT is the incorporation of gradient information which results to a further reduction in the generation of redundant evidence, by transforming point- tuples to very small sets of parameter cells. Thus, the complexity of sampling is decreased to O(N2) enabling much more fertile sampling and faster detection. An additional characteristic of C2PHT is the strict conditional transformation scheme which means that only a very small fraction of feature space becomes eligible of voting and hence, an even higher suppression of correlated noise is achieved. The C2PHT allows very economic accumulator architectures to be used. In correspondence with the high reduction of redundant votes, it greatly mitigates the burden of the peak detection process. The performance of the technique is evaluated with synthetic and real-world underwater bubble images.
Variations of (pseudo-)rotations and the Laplace-Beltrami operator on homogeneous spaces
Brezov, D. S.; Mladenova, C. D.; Mladenov, I. M.
2015-10-28
In this paper we obtain the Lie derivatives of the scalar parameters in the generalized Euler decomposition with respect to arbitrary axes under left and right deck transformations. This problem can be directly related to the representation of the angular momentum in quantum mechanics. As a particular example, we calculate the angular momentum and the corresponding quantum hamiltonian in the standard Euler and Bryan representations. Similarly, in the hyperbolic case, the Laplace-Beltrami operator is retrieved for the Iwasawa decomposition. The case of two axes is considered as well.
Transformation of full 4 × 4 Mueller matrices: a quantitative technique for biomedical diagnosis
NASA Astrophysics Data System (ADS)
He, Honghui; Chang, Jintao; He, Chao; Ma, Hui
2016-03-01
Polarization images contain abundant microstructural information of samples. Recently, as a comprehensive description of the structural and optical properties of complex media, the Mueller matrix imaging has been widely applied to biomedical studies, especially cancer detections. In previous works, we proposed a technique to transform the backscattering 3 × 3 Mueller matrices into a group of quantitative parameters with clear relationships to specific microstructures. In this paper, we extend this transformation method to full 4 × 4 Mueller matrices of both the back and forward scattering directions. Using the experimental results of phantoms and Monte Carlo simulation based on the sphere-cylinder birefringence model, we fit the Mueller matrix elements to trigonometric curves in polar coordinates and obtain a new set of transformation parameters, which can be expressed as analytical functions of 16 Mueller matrix elements. Both the experimental and simulated results demonstrate that the transformation parameters have simple relationships to the characteristic microstructural properties, including the densities and orientations of fibrous structures, the sizes of the scatterers, and the depolarization power of the samples. We also apply the transformation parameters of full 4 × 4 Mueller matrices to human liver cancerous tissues. Preliminary imaging results show that the parameters can quantitatively reflect the formation of fibrous birefringent tissues accompanying the cancerous processes. The findings presented in this study can be useful for in vivo or in vitro polarization imaging of tissues for diagnostic applications.
Fast X-ray microdiffraction techniques for studying irreversible transformations in materials
Kelly, Stephen T.; Trenkle, Jonathan C.; Koerner, Lucas J.; Barron, Sara C.; Walker, Nöel; Pouliquen, Philippe O.; Tate, Mark W.; Gruner, Sol M.; Dufresne, Eric M.; Weihs, Timothy P.; Hufnagel, Todd C.
2011-01-01
A pair of techniques have been developed for performing time-resolved X-ray microdiffraction on irreversible phase transformations. In one technique capillary optics are used to focus a high-flux broad-spectrum X-ray beam to a 60 µm spot size and a fast pixel array detector is used to achieve temporal resolution of 55 µs. In the second technique the X-rays are focused with Kirkpatrick–Baez mirrors to achieve a spatial resolution better than 10 µm and a fast shutter is used to provide temporal resolution better than 20 µs while recording the diffraction pattern on a (relatively slow) X-ray CCD camera. Example data from experiments are presented where these techniques are used to study self-propagating high-temperature synthesis reactions in metal laminate foils. PMID:21525656
Slit Function Measurement of An Imaging Spectrograph Using Fourier Transform Techniques
NASA Technical Reports Server (NTRS)
Park, Hongwoo; Swimyard, Bruce; Jakobsen, Peter; Moseley, Harvey; Greenhouse, Matthew
2004-01-01
Knowledge of a spectrograph slit function is necessary to interpret the unresolved lines in an observed spectrum. A theoretical slit function can be calculated from the sizes of the entrance slit, the detector aperture when it functions as an exit slit, the dispersion characteristic of the disperser, and the point spread function of the spectrograph. A measured slit function is preferred to the theoretical one for the correct interpretation of the spectral data. In a scanning spectrometer with a single exit slit, the slit function is easily measured. In a fixed grating/or disperser spectrograph, illuminating the entrance slit with a near monochromatic light from a pre-monochrmator or a tunable laser and varying the wavelength of the incident light can measure the slit function. Even though the latter technique had been used successfully for the slit function measurements, it had been very laborious and it would be prohibitive to an imaging spectrograph or a multi-object spectrograph that has a large field of view. We explore an alternative technique that is manageable for the measurements. In the proposed technique, the imaging spectrograph is used as a detector of a Fourier transform spectrometer. This method can be applied not only to an IR spectrograph but also has a potential to a visible/UV spectrograph including a wedge filter spectrograph. This technique will require a blackbody source of known temperature and a bolometer to characterize the interferometer part of the Fourier Transform spectrometer. This pa?er will describe the alternative slit function measurement technique using a Fourier transform spectrometer.
NASA Astrophysics Data System (ADS)
Tønning, Erik; Polders, Daniel; Callaghan, Paul T.; Engelsen, Søren B.
2007-09-01
This paper demonstrates how the multi-linear PARAFAC model can with advantage be used to decompose 2D diffusion-relaxation correlation NMR spectra prior to 2D-Laplace inversion to the T2- D domain. The decomposition is advantageous for better interpretation of the complex correlation maps as well as for the quantification of extracted T2- D components. To demonstrate the new method seventeen mixtures of wheat flour, starch, gluten, oil and water were prepared and measured with a 300 MHz nuclear magnetic resonance (NMR) spectrometer using a pulsed gradient stimulated echo (PGSTE) pulse sequence followed by a Carr-Purcell-Meiboom-Gill (CPMG) pulse echo train. By varying the gradient strength, 2D diffusion-relaxation data were recorded for each sample. From these double exponentially decaying relaxation data the PARAFAC algorithm extracted two unique diffusion-relaxation components, explaining 99.8% of the variation in the data set. These two components were subsequently transformed to the T2- D domain using 2D-inverse Laplace transformation and quantitatively assigned to the oil and water components of the samples. The oil component was one distinct distribution with peak intensity at D = 3 × 10 -12 m 2 s -1 and T2 = 180 ms. The water component consisted of two broad populations of water molecules with diffusion coefficients and relaxation times centered around correlation pairs: D = 10 -9 m 2 s -1, T2 = 10 ms and D = 3 × 10 -13 m 2 s -1, T2 = 13 ms. Small spurious peaks observed in the inverse Laplace transformation of original complex data were effectively filtered by the PARAFAC decomposition and thus considered artefacts from the complex Laplace transformation. The oil-to-water ratio determined by PARAFAC followed by 2D-Laplace inversion was perfectly correlated with known oil-to-water ratio of the samples. The new method of using PARAFAC prior to the 2D-Laplace inversion proved to have superior potential in analysis of diffusion-relaxation spectra, as it
NASA Astrophysics Data System (ADS)
Goudarzi, Alireza; Riahi, Mohammad Ali
2012-12-01
One of the most crucial challenges in seismic data processing is the reduction of the noise in the data or improving the signal-to-noise ratio. In this study, the 1D undecimated discrete wavelet transform (UDWT) has been acquired to attenuate random noise and ground roll. Wavelet domain ground roll analysis (WDGA) is applied to find the ground roll energy in the wavelet domain. The WDGA will be a substitute method for thresholding in seismic data processing. To compare the effectiveness of the WDGA method, we apply the 1D double density discrete wavelet transform (DDDWT) using soft thresholding in the random noise reduction and ground roll attenuation processes. Seismic signals intersect with ground roll in the time and frequency domains. Random noise and ground roll have many undesirable effects on pre-stack seismic data, and result in an inaccurate velocity analysis for NMO correction. In this paper, the UDWT by using the WDGA technique and DDDWT (using the soft thresholding technique) and the regular Fourier based method as f-k transform will be used and compared for seismic denoising.
End effect analysis of linear induction motor based on the wavelet transform technique
Mori, Yoshihiko; Torii, Susumu; Ebihara, Daiki
1999-09-01
HSST (High Speed Surface Transport) is currently being developed for the railway systems of urban transportation in Japan. It is used in the electromagnetic suspension and short-stator Linear Induction Motor (LIM) for the HSST. The performance of LIM is degraded due to the influence of the end effects. LIM is analyzed using the Fourier series expansion to throw light on this problem. However, to obtain the high-accuracy in this technique, the number of times for calculating is increased. In case of the Wavelet transform technique, as the Wavelet coefficients converge rapidly to zero, this technique has been applied to analyze the end effects of LIM. In this paper, the authors investigated the method for determining of mother wavelet.
NASA Astrophysics Data System (ADS)
Kalyani, Ajay Kumar; V, Lalitha K.; James, Ajit R.; Fitch, Andy; Ranjan, Rajeev
2015-02-01
A ‘powder-poling’ technique was developed to study electric field induced structural transformations in ferroelectrics exhibiting a morphotropic phase boundary (MPB). The technique was employed on soft PZT exhibiting a large longitudinal piezoelectric response (d33 ˜ 650 pC N-1). It was found that electric poling brings about a considerable degree of irreversible tetragonal to monoclinic transformation. The same transformation was achieved after subjecting the specimen to mechanical stress, which suggests an equivalence of stress and electric field with regard to the structural mechanism in MPB compositions. The electric field induced structural transformation was also found to be accompanied by a decrease in the spatial coherence of polarization.
Kalyani, Ajay Kumar; V, Lalitha K; James, Ajit R; Fitch, Andy; Ranjan, Rajeev
2015-02-25
A 'powder-poling' technique was developed to study electric field induced structural transformations in ferroelectrics exhibiting a morphotropic phase boundary (MPB). The technique was employed on soft PZT exhibiting a large longitudinal piezoelectric response (d(33) ∼ 650 pC N(-1)). It was found that electric poling brings about a considerable degree of irreversible tetragonal to monoclinic transformation. The same transformation was achieved after subjecting the specimen to mechanical stress, which suggests an equivalence of stress and electric field with regard to the structural mechanism in MPB compositions. The electric field induced structural transformation was also found to be accompanied by a decrease in the spatial coherence of polarization.
Pattern Transformation of Heat-Shrinkable Polymer by Three-Dimensional (3D) Printing Technique
Zhang, Quan; Yan, Dong; Zhang, Kai; Hu, Gengkai
2015-01-01
A significant challenge in conventional heat-shrinkable polymers is to produce controllable microstructures. Here we report that the polymer material fabricated by three-dimensional (3D) printing technique has a heat-shrinkable property, whose initial microstructure can undergo a spontaneous pattern transformation under heating. The underlying mechanism is revealed by evaluating internal strain of the printed polymer from its fabricating process. It is shown that a uniform internal strain is stored in the polymer during the printing process and can be released when heated above its glass transition temperature. Furthermore, the internal strain can be used to trigger the pattern transformation of the heat-shrinkable polymer in a controllable way. Our work provides insightful ideas to understand a novel mechanism on the heat-shrinkable effect of printed material, but also to present a simple approach to fabricate heat-shrinkable polymer with a controllable thermo-structural response. PMID:25757881
NASA Astrophysics Data System (ADS)
Górecki, Cz; Górecki, T.
2007-08-01
The parameters (temperature, activation energy) of the surface and volume glass transition (retrification process) in amorphous selenium produced by rapid quenching of the liquid phase have been determined using the EEE and DTA techniques. EEE is a surface effect connected with structural transformations in the surface layer whereas the DTA measurements give the information about the transformations occurring in the volume of the sample. It has been found that the surface retrification of selenium occurs with activation energy smaller than the volume retrification, both observed in the first heating run. The value of activation energy for the volume retrification measured in the second DTA heating run is higher compared with that measured in the first heating run. Irradiation with X-rays accelerates both the surface and volume retrification of amorphous selenium.
LACKS,S.A.
2003-10-09
Transformation, which alters the genetic makeup of an individual, is a concept that intrigues the human imagination. In Streptococcus pneumoniae such transformation was first demonstrated. Perhaps our fascination with genetics derived from our ancestors observing their own progeny, with its retention and assortment of parental traits, but such interest must have been accelerated after the dawn of agriculture. It was in pea plants that Gregor Mendel in the late 1800s examined inherited traits and found them to be determined by physical elements, or genes, passed from parents to progeny. In our day, the material basis of these genetic determinants was revealed to be DNA by the lowly bacteria, in particular, the pneumococcus. For this species, transformation by free DNA is a sexual process that enables cells to sport new combinations of genes and traits. Genetic transformation of the type found in S. pneumoniae occurs naturally in many species of bacteria (70), but, initially only a few other transformable species were found, namely, Haemophilus influenzae, Neisseria meningitides, Neisseria gonorrheae, and Bacillus subtilis (96). Natural transformation, which requires a set of genes evolved for the purpose, contrasts with artificial transformation, which is accomplished by shocking cells either electrically, as in electroporation, or by ionic and temperature shifts. Although such artificial treatments can introduce very small amounts of DNA into virtually any type of cell, the amounts introduced by natural transformation are a million-fold greater, and S. pneumoniae can take up as much as 10% of its cellular DNA content (40).
Eyben, P; Bisiaux, P; Schulze, A; Nazir, A; Vandervorst, W
2015-09-04
A new atomic force microscopy (AFM)-based technique named fast Fourier transform scanning spreading-resistance microscopy (FFT-SSRM) has been developed. FFT-SSRM offers the ability to isolate the local spreading resistance (Sr) from the parasitic series resistance (probe, bulk, and back contact). The parasitic series resistance limits the use of classical SSRM in confined volumes and on very highly doped materials, two increasingly important situations in nanoelectronic components. This is realized via a force modulation at controlled frequency (affecting the SR component) and the extraction of the resistance amplitude at the modulation frequency, performing an FFT-based lock-in deconvolution. A systematic evaluation of the FFT-SSRM performances (i.e., resolution, dynamic range, sensitivity, and repeatability) is presented. The impact of various parameters (i.e., modulation frequency and amplitude or cutoff frequency of the current amplifier) on the performances of FFT-SSRM has been evaluated. We demonstrate the possibility to overcome sensitivity losses due to tip saturation in highly doped material and the utility of the technique in two different structures, presenting isolated and confined volumes.
Reconfigurable liquid metal circuits by Laplace pressure shaping
NASA Astrophysics Data System (ADS)
Cumby, Brad L.; Hayes, Gerard J.; Dickey, Michael D.; Justice, Ryan S.; Tabor, Christopher E.; Heikenfeld, Jason C.
2012-10-01
We report reconfigurable circuits formed by liquid metal shaping with <10 pounds per square inch (psi) Laplace and vacuum pressures. Laplace pressure drives liquid metals into microreplicated trenches, and upon release of vacuum, the liquid metal dewets into droplets that are compacted to 10-100× less area than when in the channel. Experimental validation includes measurements of actuation speeds exceeding 30 cm/s, simple erasable resistive networks, and switchable 4.5 GHz antennas. Such capability may be of value for next generation of simple electronic switches, tunable antennas, adaptive reflectors, and switchable metamaterials.
A Rough Transform Technique for Extracting Lead Features from Sea Ice Imagery
1989-07-11
Funding Numbers. A ough Trclnsform lehiteFrExtracting Lead Features Program Efenrent~ 62No 5 From Sea Ice Imagery Prolec t No 13 219RK Author(s...compilIing l ead sta t ist ics from i _ge r .-. A Hlough transform technique for the semi-automated extraction of I1 at ’,rient.-ition and spacing is...Page. of Abstract. UI c_]ass i i (d [I/n g- sci f i fd Unc Iass iiHod______________ M,.NIS CRA&I 0TiC TAb C U;,jnflOj ’ t I d C]’ r A flROIIH
Baker, W.R.
1959-08-25
Transformers of a type adapted for use with extreme high power vacuum tubes where current requirements may be of the order of 2,000 to 200,000 amperes are described. The transformer casing has the form of a re-entrant section being extended through an opening in one end of the cylinder to form a coaxial terminal arrangement. A toroidal multi-turn primary winding is disposed within the casing in coaxial relationship therein. In a second embodiment, means are provided for forming the casing as a multi-turn secondary. The transformer is characterized by minimized resistance heating, minimized external magnetic flux, and an economical construction.
Viswanathan, U.K.; Kutty, T.R.G.; Ganguly, C.
1993-12-01
Solid-state transformation kinetics of a 350 grad commercial maraging steel were investigated using a nonisothermal dilatometric technique. Two solid-state reactions -- namely, precipitation of intermetallic phases from supersaturated martensite and reversion of martensite to austenite -- were identified. Determination was made of the temperatures at which the rates of these reactions reached a maximum at different heating rates. The kinetics of the individual reactions in terms of activation energy were analyzed by simplified procedures based on the Kissinger equation. An estimated activation energy of 145 {+-} 4 kJ/mol for the precipitation of intermetallic phase was in good agreement with reported results based on the isothermal hardness measurement technique. Martensite to austenite reversion was associated with an activation energy of 224 {+-} 4 kJ/mol, which is very close to the activation energy for diffusion of substitutional elements in ferrite. Results were supplemented with microstructural analysis.
Fourier transform infrared spectroscopy techniques for the analysis of drugs of abuse
NASA Astrophysics Data System (ADS)
Kalasinsky, Kathryn S.; Levine, Barry K.; Smith, Michael L.; Magluilo, Joseph J.; Schaefer, Teresa
1994-01-01
Cryogenic deposition techniques for Gas Chromatography/Fourier Transform Infrared (GC/FT-IR) can be successfully employed in urinalysis for drugs of abuse with detection limits comparable to those of the established Gas Chromatography/Mass Spectrometry (GC/MS) technique. The additional confidence of the data that infrared analysis can offer has been helpful in identifying ambiguous results, particularly, in the case of amphetamines where drugs of abuse can be confused with over-the-counter medications or naturally occurring amines. Hair analysis has been important in drug testing when adulteration of urine samples has been a question. Functional group mapping can further assist the analysis and track drug use versus time.
[A new automatic quasars recognition technique based on PCA and Hough transform].
Huang, Ling-yun; Hu, Zhan-yi
2003-02-01
The main purpose of quasar recognition is to determine the observed quasar spectrum's redshift value. Previously the template of quasar rest frame in the literature was basically constructed based on astronomers' hypotheses. Due to the inaccuracy of such a template, it is hard to determine the redshift value by matching the observed quasar spectrum with the template directly. This paper's main contributions are two-fold: Firstly, the template in our paper is constructed by the principal component analysis (PCA) method from some selected spectra with known redshift values, hence the obtained template is more realistic. Secondly, a 2D standard Hough transform, rather than a 1D Hough transform, is used. This is because although only redshift needs to be determined in our system, based on our observations, the magnitude of emission peak is also changed, hence a new parameter, namely scale parameter, is also introduced to the Hough transform to enhance the reliability of the recognition. The experiments show that the proposed technique is workable and the correct recognition rate can reach about as high as 90%.
High-contrast active cavitation imaging technique based on multiple bubble wavelet transform.
Lu, Shukuan; Xu, Shanshan; Liu, Runna; Hu, Hong; Wan, Mingxi
2016-08-01
In this study, a unique method that combines the ultrafast active cavitation imaging technique with multiple bubble wavelet transform (MBWT) for improving cavitation detection contrast was presented. The bubble wavelet was constructed by the modified Keller-Miksis equation that considered the mutual effect among bubbles. A three-dimensional spatial model was applied to simulate the spatial distribution of multiple bubbles. The effects of four parameters on the signal-to-noise ratio (SNR) of cavitation images were evaluated, including the following: initial radii of bubbles, scale factor in the wavelet transform, number of bubbles, and the minimum inter-bubble distance. And the other two spatial models and cavitation bubble size distributions were introduced in the MBWT method. The results suggested that in the free-field experiments, the averaged SNR of images acquired by the MBWT method was improved by 7.16 ± 0.09 dB and 3.14 ± 0.14 dB compared with the values of images acquired by the B-mode and single bubble wavelet transform (SBWT) methods. In addition, in the tissue experiments, the averaged cavitation-to-tissue ratio of cavitation images acquired by the MBWT method was improved by 4.69 ± 0.25 dB and 1.74± 0.29 dB compared with that of images acquired by B-mode and SBWT methods.
Laplace DLTS investigation of transition metal-hydrogen complexes in germanium
NASA Astrophysics Data System (ADS)
Gurimskaya, Y.; Mesli, A.
2014-02-01
High-resolution Laplace DLTS technique has been used to examine fine structures in the carrier emission processes hidden in the broad conventional DLTS peaks recorded in germanium samples, doped by several transition metals - Ni, Cr and Fe. These structures are found to be correlated with the acceptors, related to mentioned impurities, and also with possible presence of hydrogen-related defects. A link explaining interaction of transition metals with hydrogen due to the applied chemical treatment during sample preparation process is revealed and compared to what is known in silicon.
Bicubic B-spline interpolation method for two-dimensional Laplace's equations
NASA Astrophysics Data System (ADS)
Abd Hamid, Nur Nadiah; Majid, Ahmad Abd.; Ismail, Ahmad Izani Md.
2013-04-01
Two-dimensional Laplace's equation is solved using bicubic B-spline interpolation method. An arbitrary surface with some unknown coefficients is generated using bicubic B-spline surface's formula. This surface is presumed to be the solution for the equation. The values of the coefficients are calculated by spline interpolation technique using the corresponding differential equations and boundary conditions. This method produces approximated analytical solution for the equation. A numerical example will be presented along with a comparison of the results with finite element and isogeometrical methods.
Vuiblet, Vincent; Fere, Michael; Gobinet, Cyril; Birembaut, Philippe; Piot, Olivier; Rieu, Philippe
2016-08-01
Renal interstitial fibrosis and interstitial active inflammation are the main histologic features of renal allograft biopsy specimens. Fibrosis is currently assessed by semiquantitative subjective analysis, and color image analysis has been developed to improve the reliability and repeatability of this evaluation. However, these techniques fail to distinguish fibrosis from constitutive collagen or active inflammation. We developed an automatic, reproducible Fourier-transform infrared (FTIR) imaging-based technique for simultaneous quantification of fibrosis and inflammation in renal allograft biopsy specimens. We generated and validated a classification model using 49 renal biopsy specimens and subsequently tested the robustness of this classification algorithm on 166 renal grafts. Finally, we explored the clinical relevance of fibrosis quantification using FTIR imaging by comparing results with renal function at 3 months after transplantation (M3) and the variation of renal function between M3 and M12. We showed excellent robustness for fibrosis and inflammation classification, with >90% of renal biopsy specimens adequately classified by FTIR imaging. Finally, fibrosis quantification by FTIR imaging correlated with renal function at M3, and the variation in fibrosis between M3 and M12 correlated well with the variation in renal function over the same period. This study shows that FTIR-based analysis of renal graft biopsy specimens is a reproducible and reliable label-free technique for quantifying fibrosis and active inflammation. This technique seems to be more relevant than digital image analysis and promising for both research studies and routine clinical practice.
Laplace-domain waveform inversion versus refraction-traveltime tomography
NASA Astrophysics Data System (ADS)
Bae, Ho Seuk; Pyun, Sukjoon; Shin, Changsoo; Marfurt, Kurt J.; Chung, Wookeen
2012-07-01
Geophysicists and applied mathematicians have proposed a rich suite of long-wavelength velocity estimation algorithms to construct starting velocity models for subsequent pre-stack depth migration and inversion. Refraction-traveltime tomography derives subsurface velocity models from picked first-arrival traveltimes. In contrast, Laplace-domain waveform inversion recovers long-wavelength velocity structure using the weighted amplitudes of first and later arrivals. There are several implementations of first-arrival traveltime inversion, with most based on ray tracing, and some based on the damped monochromatic wave equation, which accurately represent simple and finite-frequency first arrivals. Computationally, Laplace-domain wavefield inversion is quite similar to refraction-traveltime tomography using damped monochromatic wavefield, but the objective functions used in inversion are radically different. As in classical ray trace-based traveltime inversion, the objective of refraction-traveltime tomography using damped monochromatic wavefield is to match the phase (traveltime) of the first arrival of each measured seismic trace. In contrast, the objective of Laplace-domain wavefield inversion is to match the weighted amplitudes of both first and later arrivals to the weighted amplitudes of the measured seismic trace. Principles of refraction-traveltime tomography were used to generate velocity models of the earth one century ago. Laplace-domain waveform inversion is a more recently introduced algorithm and has been less rigorously studied by the seismic research community, with many workers believing it be equivalent to finite-frequency first-arrival traveltime tomography. We show that Laplace-domain waveform inversion is both theoretically and empirically different from finite-frequency first-arrival traveltime tomography. Specifically, we examine the Jacobian (sensitivity) kernels used in the two inversion schemes to quantify the different sensitivities (and hence
Choi, Hyun Ho; Lee, Ju Hwan; Kim, Sung Min; Park, Sung Yun
2015-01-01
Here, the speckle noise in ultrasonic images is removed using an image fusion-based denoising method. To optimize the denoising performance, each discrete wavelet transform (DWT) and filtering technique was analyzed and compared. In addition, the performances were compared in order to derive the optimal input conditions. To evaluate the speckle noise removal performance, an image fusion algorithm was applied to the ultrasound images, and comparatively analyzed with the original image without the algorithm. As a result, applying DWT and filtering techniques caused information loss and noise characteristics, and did not represent the most significant noise reduction performance. Conversely, an image fusion method applying SRAD-original conditions preserved the key information in the original image, and the speckle noise was removed. Based on such characteristics, the input conditions of SRAD-original had the best denoising performance with the ultrasound images. From this study, the best denoising technique proposed based on the results was confirmed to have a high potential for clinical application.
Scale Invariant Feature Transform Technique for Weed Classification in Oil Palm Plantation
NASA Astrophysics Data System (ADS)
Hawari Ghazali, Kamarul; Marzuki Mustafa, Mohd.; Hussain, Aini; Razali, Saifudin
This study presents a new and robust technique using Scale Invariant Feature Transform (SIFT) for weed classification in oil palm plantation. The proposed SIFT classification technique was developed to overcome problem in real application of image processing such as varies of lighting densities, resolution and target range which contributed to classification accuracy. In this study, SIFT classification algorithm is used to extract a set of feature vectors to represent the input image. The set of feature vectors then can be used to classify weed. In general, the weeds can be classified as either broad or narrow. Based on this classification, a decision will be made to control the strategy of weed infestation in oil palm plantations. The effectiveness of the robust SIFT technique has been tested offline where the input images were captured under varies conditions such as different lighting effects, ambiguity resolution values, variable range of object and many sizes of weed which simulate the actual field conditions. The proposed SIFT resulted in over 95.7% accuracy of classification of weed in palm oil plantation.
NASA Technical Reports Server (NTRS)
Mccoy, M. J.
1980-01-01
Various finite difference techniques used to solve Laplace's equation are compared. Curvilinear coordinate systems are used on two dimensional regions with irregular boundaries, specifically, regions around circles and airfoils. Truncation errors are analyzed for three different finite difference methods. The false boundary method and two point and three point extrapolation schemes, used when having the Neumann boundary condition are considered and the effects of spacing and nonorthogonality in the coordinate systems are studied.
Desai, Satish R; Dharwadkar, Sanjiv R
2008-01-01
Differential scanning calorimetric (DSC) curves recorded for ornidazole drug during heating and cooling showed that the drug which melted around 86.1 degrees C undercooled to well below ambient room temperature of 27 degrees C during the cooling cycle. The undercooled melt kept in the freezer at 0 degree C for 10 days duration also remained in the viscous liquid form. This liquid on taking out from the freezer after ten days and ageing at ambient room temperature of 27 degrees C for 12 h transformed into white powder. The DSC pattern recorded for this white powder consisted of two prominent endothermic peaks beginning at 73.2 and 85.9 degrees C, respectively, suggesting that the powder consisted of a mixture of more than one phase. The X-ray diffraction (XRD) pattern recorded for this powder showed it to be a mixture of semi-crystalline phase and the original compound. The semi-crystalline phase melted at 73.2 degrees C prior to the melting of original compound at 85.9 degrees C. This phase on further ageing for 7 days transforms almost completely to its original form. DSC observations were corroborated by XRD and scanning electron microscopy (SEM) techniques.
Prepreg cure monitoring using diffuse reflectance-FTIR. [Fourier Transform Infrared Technique
NASA Technical Reports Server (NTRS)
Young, P. R.; Chang, A. C.
1984-01-01
An in situ diffuse reflectance-Fourier transform infrared technique was developed to determine infrared spectra of graphite fiber prepregs as they were being cured. A bismaleimide, an epoxy, and addition polyimide matrix resin prepregs were studied. An experimental polyimide adhesive was also examined. Samples were positioned on a small heater at the focal point of diffuse reflectance optics and programmed at 15 F/min while FTIR spectra were being scanned, averaged, and stored. An analysis of the resulting spectra provided basic insights into changes in matrix resin molecular structure which accompanied reactions such as imidization and crosslinking. An endo-exothermal isomerization involving reactive end-caps was confirmed for the addition polyimide prepregs. The results of this study contribute to a fundamental understanding of the processing of composites and adhesives. Such understanding will promote the development of more efficient cure cycles.
NASA Technical Reports Server (NTRS)
Tarbell, T. D.; Title, A. M.
1976-01-01
Fourier techniques have been exhaustively calibrated using Unno's (1956) results for the absorption profile of a simple Zeeman triplet. If a simple transformation is applied to the normalized line depths, then magnetic-field strengths and inclination angles can be measured very accurately from noisy saturated line profiles. Systematic errors caused by saturation effects can be estimated and reduced by varying one parameter. When a significant fraction of the line profile is unsplit and unpolarized, large errors may be made in measurements of low fields, unless the line is sufficiently weak. For a weak line, a vertical field of 1600 gauss can be measured to 10% accuracy even when 70% of the line profile is stray light. These stray-light errors are troublesome in measuring fields of gaps and pores but not sunspots. Numerical results of the error analysis are presented graphically.
1985-12-02
general for this Sturm - Liouville problem, 9 I" > , .: -. , - i::.~ . .. . . . " . . .’,,, ;,... . . .... , .... ,..... . . .,. .. - . . ..: , Wn-A n sin Sn...extension of the Sturm - Liouville approach (p. 414 of Ref. 15). Instead, the Laplace transform technique (Chapter XII in Ref. 14) is used. The standard...t) - K2 VT2 (Ot) (zero divergence at interface) (18) 11 Notice particularly that the temperature pulse in the IC of the Sturm - Liouville problem has
NASA Astrophysics Data System (ADS)
Chapman, Michael G.
The purpose of this work is to validate that the martensitic transformations predicted by the model from Xian Chen and Dick James from the University of Minnesota. This model uses multiple criteria for compatibility between the austenite and martensite lattices including limitations of the middle eigenvalue of the transformation stretch matrix and what are called the "cofactor conditions." An alloy satisfying these criteria was found, (Au30Cu25Zn 45) but the traditional methods for verifying the shape and crystallographic orientation relationships of the transformation could not be used (serial sectioning and 3D Electron Backscatter Diffraction (EBSD)). The first method developed in this work uses the intensity peak of the background of EBSD patterns to extract surface topography measurements. Monte Carlo simulations were used to calculate the deviation from specular reflection for electrons on different materials at varying voltages. The geometric setup of the EBSD camera and the sample were then used with the experimentally measured intensity peak location on the camera to calculate the surface normal vectors for each point on a sample. A proof of concept experiment was first performed on the Tin sphere calibration standard, in which the surface normal vectors were found within around 0:5ffi error near the standard EBSD sample orientation. This technique was then used to measure the surface relief caused by the martensitic transformation of the AuCuZn alloy which can be matched to predicted surface shearing values to confirm the Chen/James model. The second method developed in this thesis measures the out-of-plane grain boundary inclination angle using 2D EBSD. This utilizes the penetration depth of the electron interaction volume, and is measured by calculating the proportion of the pattern that is created from each grain. This is completed by performing dot products between an EBSD line scan across the grain boundary and reference patterns taken from the bulk
Nodal Solutions for Supercritical Laplace Equations
NASA Astrophysics Data System (ADS)
Dalbono, Francesca; Franca, Matteo
2016-11-01
In this paper we study radial solutions for the following equation Δ u(x)+f (u(x), |x|) = 0, where {x in {Rn}}, n > 2, f is subcritical for r small and u large and supercritical for r large and u small, with respect to the Sobolev critical exponent {2^{*} = 2n/n-2}. The solutions are classified and characterized by their asymptotic behaviour and nodal properties. In an appropriate super-linear setting, we give an asymptotic condition sufficient to guarantee the existence of at least one ground state with fast decay with exactly j zeroes for any j ≥ 0. Under the same assumptions, we also find uncountably many ground states with slow decay, singular ground states with fast decay and singular ground states with slow decay, all of them with exactly j zeroes. Our approach, based on Fowler transformation and invariant manifold theory, enables us to deal with a wide family of potentials allowing spatial inhomogeneity and a quite general dependence on u. In particular, for the Matukuma-type potential, we show a kind of structural stability.
Transition metals (Ti and Co) in silicon and their complexes with hydrogen: A Laplace DLTS study
NASA Astrophysics Data System (ADS)
Kolkovsky, Vl.; Scheffler, L.; Weber, J.
2014-04-01
The electrical properties of transition metals (TM) in Si were often determined by means of the conventional deep level transient spectroscopy (DLTS) technique. In the present study we demonstrate that the poor resolution of the conventional DLTS technique could lead to the wrong interpretation of the experimental data. On the example of well-known lifetime killers such as titanium and cobalt we show that the dominant defects appeared in samples doped with these impurities were previously wrongly attributed to different charged states of interstitial Ti and substitutional Co. Applying the high-resolution Laplace DLTS technique we re-examine the origin of these defects. Some of these defects will be shown to react with H and shallow acceptors leading to the appearance of new complex defects in the band gap of Si. Their nature will also be discussed in the present paper.
NASA Astrophysics Data System (ADS)
Kong, Weiwei; Liu, Jianping
2013-01-01
A new technique for image fusion based on nonsubsampled shearlet transform (NSST) and improved pulse-coupled neural network (PCNN) is proposed. NSST, as a novel multiscale geometric analysis tool, can be optimally efficient in representing images and capturing the geometric features of multidimensional data. As a result, NSST is introduced into the area of image fusion to complete the decompositions of source images in any scale and any direction. Then the basic PCNN model is improved to be improved PCNN (IPCNN), which is more concise and more effective. IPCNN adopts the contrast of each pixel in images as the linking strength β, and the time matrix T of subimages can be obtained via the synchronous pulse-burst property. By using IPCNN, the fused subimages can be achieved. Finally, the final fused image can be obtained by using inverse NSST. The numerical experiments demonstrate that the new technique presented in this paper is competitive in the field of image fusion in terms of both fusion performance and computational efficiency.
NASA Astrophysics Data System (ADS)
Tan, T. L.; Ng, L. L.; Lim, L. C.
2013-10-01
The mineralogical properties of black nephrite jade from Western Australia are studied by Fourier transform infrared (FTIR) spectroscopy using both transmission and specular reflectance techniques in the 4000-400 cm-1 wavenumber region. The infrared absorption peaks in the 3700-3600 cm-1 region which are due to the O-H stretching mode provides a quantitative analysis of the Fe/(Fe+Mg) ratio in the mineral composition of jade samples. The Fe/(Fe+Mg) percentage in black nephrite is found to be higher than that in green nephrite, but comparable to that of actinolite (iron-rich nephrite). This implies that the mineralogy of black nephrite is closer to actinolite than tremolite. The jade is also characterized using Raman spectroscopy in the 1200-200 cm-1 region. Results from FTIR and Raman spectroscopic data of black nephrite jade are compared with those of green nephrite jade from New Zealand and jadeite jade from Myanmar. Black nephrite appears to have a slightly different chemical composition from green nephrite. Spectra from FTIR and Raman spectroscopic techniques were found to be useful in differentiating black nephrite, green nephrite, and green jadeite jades. Furthermore, data on refractive index, specific gravity, and hardness of black nephrite jade are measured and compared with those of green nephrite and of jadeite jade.
Vector Helmholtz-Gauss and vector Laplace-Gauss beams.
Bandres, Miguel A; Gutiérrez-Vega, Julio C
2005-08-15
We demonstrate the existence of vector Helmholtz-Gauss (vHzG) and vector Laplace-Gauss beams that constitute two general families of localized vector beam solutions of the Maxwell equations in the paraxial approximation. The electromagnetic components are determined starting from the scalar solutions of the two-dimensional Helmholtz and Laplace equations, respectively. Special cases of the vHzG beams are TE and TM Gaussian vector beams, nondiffracting vector Bessel beams, polarized Bessel-Gauss beams, modes in cylindrical waveguides and cavities, and scalar Helmholtz-Gauss beams. The general expression of the vHzG beams can be used straightforwardly to obtain vector Mathieu-Gauss and vector parabolic-Gauss beams, which to our knowledge have not yet been reported.
Graph Laplace for occluded face completion and recognition.
Deng, Yue; Dai, Qionghai; Zhang, Zengke
2011-08-01
This paper proposes a spectral-graph-based algorithm for face image repairing, which can improve the recognition performance on occluded faces. The face completion algorithm proposed in this paper includes three main procedures: 1) sparse representation for partially occluded face classification; 2) image-based data mining; and 3) graph Laplace (GL) for face image completion. The novel part of the proposed framework is GL, as named from graphical models and the Laplace equation, and can achieve a high-quality repairing of damaged or occluded faces. The relationship between the GL and the traditional Poisson equation is proven. We apply our face repairing algorithm to produce completed faces, and use face recognition to evaluate the performance of the algorithm. Experimental results verify the effectiveness of the GL method for occluded face completion.
NASA Astrophysics Data System (ADS)
Long, C. L.
1991-02-01
Multivariate calibration techniques can reduce the time required for routine testing and can provide new methods of analysis. Multivariate calibration is commonly used with near infrared reflectance analysis (NIRA) and Fourier transform infrared (FTIR) spectroscopy. Two feasibility studies were performed to determine the capability of NIRA, using multivariate calibration techniques, to perform analyses on the types of samples that are routinely analyzed at this laboratory. The first study performed included a variety of samples and indicated that NIRA would be well-suited to perform analyses on selected materials properties such as water content and hydroxyl number on polyol samples, epoxy content on epoxy resins, water content of desiccants, and the amine values of various amine cure agents. A second study was performed to assess the capability of NIRA to perform quantitative analysis of hydroxyl numbers and water contents of hydroxyl-containing materials. Hydroxyl number and water content were selected for determination because these tests are frequently run on polyol materials and the hydroxyl number determination is time consuming. This study pointed out the necessity of obtaining calibration standards identical to the samples being analyzed for each type of polyol or other material being analyzed. Multivariate calibration techniques are frequently used with FTIR data to determine the composition of a large variety of complex mixtures. A literature search indicated many applications of multivariate calibration to FTIR data. Areas identified where quantitation by FTIR would provide a new capability are quantitation of components in epoxy and silicone resins, polychlorinated biphenyls (PCBs) in oils, and additives to polymers.
Four Poission-Laplace Theory of Gravitation (I)
NASA Astrophysics Data System (ADS)
Nyambuya, Golden Gadzirayi
2015-08-01
The Poisson-Laplace equation is a working and acceptable equation of gravitation which is mostly used or applied in its differential form in Magneto-Hydro-Dynamic (MHD) modelling of e.g. molecular clouds. From a general relativistic standpoint, it describes gravitational fields in the region of low spacetime curvature as it emerges in the weak field limit. For non-static gravitational fields, this equation is not generally covariant. On the requirements of general covariance, this equation can be extended to include a time-dependent component, in which case one is led to the Four Poisson-Laplace equation. We solve the Four Poisson-Laplace equation for radial solutions, and apart from the Newtonian gravitational component, we obtain four new solutions leading to four new gravitational components capable (in-principle) of explaining e.g. the Pioneer anomaly, the Titius-Bode Law and the formation of planetary rings. In this letter, we focus only on writing down these solutions. The task showing that these new solutions might explain the aforesaid gravitational anomalies has been left for separate future readings.
The Laplace resonance in the Kepler-60 planetary system
NASA Astrophysics Data System (ADS)
Goździewski, K.; Migaszewski, C.; Panichi, F.; Szuszkiewicz, E.
2016-01-01
We investigate the dynamical stability of the Kepler-60 planetary system with three super-Earths. We determine their orbital elements and masses by transit timing variation (TTV) data spanning quarters Q1-Q16 of the Kepler mission. The system is dynamically active but the TTV data constrain masses to ˜4 M⊕ and orbits in safely wide stable zones. The observations prefer two types of solutions. The true three-body Laplace mean-motion resonance (MMR) exhibits the critical angle librating around ≃45° and aligned apsides of the inner and outer pair of planets. In the Laplace MMR formed through a chain of two-planet 5:4 and 4:3 MMRs, all critical angles librate with small amplitudes ˜30° and apsidal lines in planet's pairs are anti-aligned. The system is simultaneously locked in a three-body MMR with librations amplitude ≃10o. The true Laplace MMR can evolve towards a chain of two-body MMRs in the presence of planetary migration. Therefore, the three-body MMR formed in this way seems to be more likely state of the system. However, the true three-body MMR cannot be disregarded a priori and it remains a puzzling configuration that may challenge the planet formation theory.
Phaechamud, Thawatchai; Tuntarawongsa, Sarun
2016-01-01
Eutectic solvent can solubilize high amount of some therapeutic compounds. Volatile eutectic solvent is interesting to be used as solvent in the preparation of nanosuspension with emulsion solvent evaporation technique. The mechanism of transformation from the eutectic emulsion to nanosuspension was investigated in this study. The 30% w/w ibuprofen eutectic solution was used as the internal phase, and the external phase is composed of Tween 80 as emulsifier. Ibuprofen nanosuspension was prepared by eutectic emulsion solvent evaporating method followed with ultrasonication. During evaporation process, the ibuprofen concentration in emulsion droplets was increased leading to a drug supersaturation but did not immediately recrystallize because of low glass transition temperature (Tg) of ibuprofen. The contact angle of the internal phase on ibuprofen was apparently lower than that of the external phase at all times of evaporation, indicating that the ibuprofen crystals were preferentially wetted by the internal phase than the external phase. From calculated dewetting value ibuprofen crystallization occurred in the droplet. Crystallization of the drug was initiated with external mechanical force, and the particle size of the drug was larger due to Ostwald ripening. Cavitation force from ultrasonication minimized the ibuprofen crystals to the nanoscale. Particle size and zeta potential of formulated ibuprofen nanosuspension were 330.87±51.49 nm and −31.1±1.6 mV, respectively, and exhibited a fast dissolution. Therefore, the combination of eutectic emulsion solvent evaporation method with ultrasonication was favorable for fabricating an ibuprofen nanosuspension, and the transformation mechanism was attained successfully. PMID:27366064
Phaechamud, Thawatchai; Tuntarawongsa, Sarun
2016-01-01
Eutectic solvent can solubilize high amount of some therapeutic compounds. Volatile eutectic solvent is interesting to be used as solvent in the preparation of nanosuspension with emulsion solvent evaporation technique. The mechanism of transformation from the eutectic emulsion to nanosuspension was investigated in this study. The 30% w/w ibuprofen eutectic solution was used as the internal phase, and the external phase is composed of Tween 80 as emulsifier. Ibuprofen nanosuspension was prepared by eutectic emulsion solvent evaporating method followed with ultrasonication. During evaporation process, the ibuprofen concentration in emulsion droplets was increased leading to a drug supersaturation but did not immediately recrystallize because of low glass transition temperature (T g) of ibuprofen. The contact angle of the internal phase on ibuprofen was apparently lower than that of the external phase at all times of evaporation, indicating that the ibuprofen crystals were preferentially wetted by the internal phase than the external phase. From calculated dewetting value ibuprofen crystallization occurred in the droplet. Crystallization of the drug was initiated with external mechanical force, and the particle size of the drug was larger due to Ostwald ripening. Cavitation force from ultrasonication minimized the ibuprofen crystals to the nanoscale. Particle size and zeta potential of formulated ibuprofen nanosuspension were 330.87±51.49 nm and -31.1±1.6 mV, respectively, and exhibited a fast dissolution. Therefore, the combination of eutectic emulsion solvent evaporation method with ultrasonication was favorable for fabricating an ibuprofen nanosuspension, and the transformation mechanism was attained successfully.
NASA Astrophysics Data System (ADS)
Riel, B.; Simons, M.; Agram, P.
2012-12-01
Transients are a class of deformation signals on the Earth's surface that can be described as non-periodic accumulation of strain in the crust. Over seismically and volcanically active regions, these signals are often challenging to detect due to noise and other modes of deformation. Geodetic datasets that provide precise measurements of surface displacement over wide areas are ideal for exploiting both the spatial and temporal coherence of transient signals. We present an extension to the Multiscale InSAR Time Series (MInTS) approach for analyzing geodetic data by combining the localization benefits of wavelet transforms (localizing signals in space) with sparse optimization techniques (localizing signals in time). Our time parameterization approach allows us to reduce geodetic time series to sparse, compressible signals with very few non-zero coefficients corresponding to transient events. We first demonstrate the temporal transient detection by analyzing GPS data over the Long Valley caldera in California and along the San Andreas fault near Parkfield, CA. For Long Valley, we are able to resolve the documented 2002-2003 uplift event with greater temporal precision. Similarly for Parkfield, we model the postseismic deformation by specific integrated basis splines characterized by timescales that are largely consistent with postseismic relaxation times. We then apply our method to ERS and Envisat InSAR datasets consisting of over 200 interferograms for Long Valley and over 100 interferograms for Parkfield. The wavelet transforms reduce the impact of spatially correlated atmospheric noise common in InSAR data since the wavelet coefficients themselves are essentially uncorrelated. The spatial density and extended temporal coverage of the InSAR data allows us to effectively localize ground deformation events in both space and time with greater precision than has been previously accomplished.
Some results on the integral transforms and applications to differential equations
Eltayeb, Hassan; Kilicman, Adem
2010-11-11
In this paper we give some remark about the relationship between Sumudu and Laplace transforms, further; for the comparison purpose, we apply both transforms to solve partial differential equations to see the differences and similarities.
Application of Wavelet Transform Techniques to Spread Spectrum Demodulation and Jamming
1993-02-26
This project has investigated the application of wavelet methods in spread spectrum communications. Use of the wavelet transform as an alternative to...signals has been explored. Direct application of the wavelet transform was found to not offer performance advantages over the Fourier transform in...this application. However, use of the wavelet transform in conjunction with Fourier methods provided an efficient hybrid framework for precise
Deep levels of vacancy-hydrogen centers in silicon studied by Laplace DLTS
NASA Astrophysics Data System (ADS)
Bonde Nielsen, K.; Dobaczewski, L.; Goscinski, K.; Bendesen, R.; Andersen, Ole; Bech Nielsen, B.
1999-12-01
We identify the acceptor levels (-/0) of the VH and V2H defects in silicon from comparison of DLTS and EPR annealing data. The levels are very close to each other and close to the acceptor level of the PV defect (the E-center) as well. In order to separate them, we have applied the high-resolution technique of Laplace DLTS and compared the formation and annealing properties of defects generated by implantation of hydrogen or helium. We further applied Laplace DLTS in combination with uniaxial stress to study the acceptor level at Ec-Et=0.31 eV previously assigned to a vacancy-hydrogen-oxygen defect. We find, in accordance with recent EPR measurements, that the defect displays orthorhombic-I symmetry and rule out that it contains two hydrogen atoms. The defect can be understood as a single hydrogen atom bound inside the A-center, the well-known VO defect of silicon, and we denote it VOH accordingly. The observed orthorhombic-I symmetry arises because the hydrogen atom (at T=160 K) swiftly jumps among two equivalent sites across the (1 1 0) plane that contains the Si-O-Si bond. Previous studies have shown that hydrogenation of oxygen-rich electron-irradiated samples leads to the formation of VOH with simultaneous depletion of the A-center. Our structural data are in accordance with this dynamic behavior.
Philip Ye, X; Liu, Lu; Hayes, Douglas; Womac, Alvin; Hong, Kunlun; Sokhansanj, Shahab
2008-10-01
The objectives of this research were to determine the variation of chemical composition across botanical fractions of cornstover, and to probe the potential of Fourier transform near-infrared (FT-NIR) techniques in qualitatively classifying separated cornstover fractions and in quantitatively analyzing chemical compositions of cornstover by developing calibration models to predict chemical compositions of cornstover based on FT-NIR spectra. Large variations of cornstover chemical composition for wide calibration ranges, which is required by a reliable calibration model, were achieved by manually separating the cornstover samples into six botanical fractions, and their chemical compositions were determined by conventional wet chemical analyses, which proved that chemical composition varies significantly among different botanical fractions of cornstover. Different botanic fractions, having total saccharide content in descending order, are husk, sheath, pith, rind, leaf, and node. Based on FT-NIR spectra acquired on the biomass, classification by Soft Independent Modeling of Class Analogy (SIMCA) was employed to conduct qualitative classification of cornstover fractions, and partial least square (PLS) regression was used for quantitative chemical composition analysis. SIMCA was successfully demonstrated in classifying botanical fractions of cornstover. The developed PLS model yielded root mean square error of prediction (RMSEP %w/w) of 0.92, 1.03, 0.17, 0.27, 0.21, 1.12, and 0.57 for glucan, xylan, galactan, arabinan, mannan, lignin, and ash, respectively. The results showed the potential of FT-NIR techniques in combination with multivariate analysis to be utilized by biomass feedstock suppliers, bioethanol manufacturers, and bio-power producers in order to better manage bioenergy feedstocks and enhance bioconversion.
Muik, Barbara; Lendl, Bernhard; Molina-Díaz, Antonio; Ortega-Calderón, Domingo; Ayora-Cañada, María José
2004-10-06
Fourier transform Raman spectroscopy combined with pattern recognition has been used to discriminate olives of different qualities. They included samples of sound olives, olives with frostbite, olives that have been collected from the ground, fermented olives, and olive samples with diseases. Milled olives were measured in a dedicated sample cup, which was rotated during spectrum acquisition. A preliminary study of the data set structure was performed using hierarchical cluster analysis and principal component analysis. Two supervised pattern recognition techniques, K-nearest neighbors and soft independent modeling of class analogy (SIMCA), were tested using a "leave-a-fourth-out" cross-validation procedure. SIMCA provided the best results, with prediction abilities of 95% for sound, 93% for frostbite, 96% for ground, and 92% for fermented olives. The olive samples with diseases (too few to define a class) were included in the validation and recognized as not belonging to any class. None of the damaged olive samples was wrongly predicted to the class of sound olives. With this approach a selection of sound olives for the production of high-quality virgin olive oil can be achieved.
Gravitational waves from rotating neutron stars and evaluation of fast chirp transform techniques
NASA Astrophysics Data System (ADS)
Strohmayer, Tod E.
2002-04-01
X-ray observations suggest that neutron stars in low mass x-ray binaries (LMXB) are rotating with frequencies in the range 300-600 Hz. These spin rates are significantly less than the break-up rates for essentially all realistic neutron star equations of state, suggesting that some process may limit the spin frequencies of accreting neutron stars to this range. If the accretion-induced spin up torque is in equilibrium with gravitational radiation losses, these objects could be interesting sources of gravitational waves. I present a brief summary of current measurements of neutron star spins in LMXBs based on the observations of high-Q oscillations during thermonuclear bursts (so-called 'burst oscillations'). Further measurements of neutron star spins will be important in exploring the gravitational radiation hypothesis in more detail. To this end, I also present a study of fast chirp transform (FCT) techniques as described by Jenet and Prince (Prince T A and Jenet F A 2000 Phys. Rev. D 62 122001) in the context of searching for the chirping signals observed during x-ray bursts.
Gravitational Waves from Rotating Neutron Stars and Evaluation of fast Chirp Transform Techniques
NASA Technical Reports Server (NTRS)
Strohmayer, Tod E.; White, Nicholas E. (Technical Monitor)
2000-01-01
X-ray observations suggest that neutron stars in low mass X-ray binaries (LMXB) are rotating with frequencies from 300 - 600 Hz. These spin rates are significantly less than the break-up rates for essentially all realistic neutron star equations of state, suggesting that some process may limit the spin frequencies of accreting neutron stars to this range. If the accretion induced spin up torque is in equilibrium with gravitational radiation losses, these objects could be interesting sources of gravitational waves. I present a brief summary of current measurements of neutron star spins in LMXBs based on the observations of high-Q oscillations during thermonuclear bursts (so called 'burst oscillations'). Further measurements of neutron star spins will be important in exploring the gravitational radiation hypothesis in more detail. To this end I also present a study of fast chirp transform (FCT) techniques as described by Jenet and Prince in the context of searching for the chirping signals observed during X-ray bursts.
Color image encryption based on fractional Fourier transforms and pixel scrambling technique
NASA Astrophysics Data System (ADS)
Zhao, Jianlin; Lu, Hongqiang; Fan, Qi
2007-01-01
Color image encryption based on fractional Fourier transform (FRT) and pixel scrambling technique is presented in this paper. In general, color (RGB) image cannot be directly encrypted using a traditional setup for optical information processing, because which is only adapted to process two-dimensional gray image. In the proposed method, a three-dimensional RGB image is decomposed to three two-dimensional gray images (R, G and B values of the color image), and the encryption operation will be done on each two-dimensional gray image, then the encoded color image is available by composing the three two-dimensional encrypted images. The decryption process is an inverse of the encryption. The optical encrypting systems based on the presented method is proposed and simulated. Some results of computer simulation are presented to verify the flexibility and the reliability of this method. The quality of decrypted images would be debased with the difference of the fractional order. The frustrated decryption of monochromic image will affect the color of decrypted image. At the end of this paper, an all-optical and photoelectric encryption/decryption systems solution are presented, and the principle of selecting optical devices are also given.
Optical transformation based image encryption and data embedding techniques using MATLAB
NASA Astrophysics Data System (ADS)
Bhattacharya, Debalina; Ghosh, Ajay
2015-06-01
The proposed work describes optical transformations such as Fourier transformation and Fresnel transformation based encryption and decryption of images using random phase masks (RPMs). The encrypted images have been embedded in some secret cover files of other formats like text files, word files, audio files etc to increase the robustness in the security applications. So, if any one wants to send confidential documents, it will be difficult for the interloper to unhide the secret information. The whole work has been done in MATLAB®
Open active cloaking and illusion devices for the Laplace equation
NASA Astrophysics Data System (ADS)
Ma, Qian; Yang, Fan; Jin, Tian Yu; Lei Mei, Zhong; Cui, Tie Jun
2016-04-01
We propose open active cloaking and illusion devices for the Laplace equation. Compared with the closed configurations of active cloaking and illusion devices, we focus on improving the distribution schemes for the controlled sources, which do not have to surround the protected object strictly. Instead, the controlled sources can be placed in several small discrete clusters, and produce the desired voltages along the controlled boundary, to actively hide or disguise the protected object. Numerical simulations are performed with satisfactory results, which are further validated by experimental measurements. The open cloaking and illusion devices have many advantages over the closed configurations in various potential applications.
Investigations of Tides from the Antiquity to Laplace
NASA Astrophysics Data System (ADS)
Deparis, Vincent; Legros, Hilaire; Souchay, Jean
Tidal phenomena along the coasts were known since the prehistoric era, but a long journey of investigations through the centuries was necessary from the Greco-Roman Antiquity to the modern era to unravel in a quasi-definitive way many secrets of the ebb and flow. These investigations occupied the great scholars from Aristotle to Galileo, Newton, Euler, d'Alembert, Laplace, and the list could go on. We will review the historical steps which contributed to an increasing understanding of the tides.
Enclosure method for the p-Laplace equation
NASA Astrophysics Data System (ADS)
Brander, Tommi; Kar, Manas; Salo, Mikko
2015-04-01
We study the enclosure method for the p-Calderón problem, which is a nonlinear generalization of the inverse conductivity problem due to Calderón that involves the p-Laplace equation. The method allows one to reconstruct the convex hull of an inclusion in the nonlinear model by using exponentially growing solutions introduced by Wolff. We justify this method for the penetrable obstacle case, where the inclusion is modelled as a jump in the conductivity. The result is based on a monotonicity inequality and the properties of the Wolff solutions.
Newton, laplace, and the epistemology of systems biology.
Bittner, Michael L; Dougherty, Edward R
2012-01-01
For science, theoretical or applied, to significantly advance, researchers must use the most appropriate mathematical methods. A century and a half elapsed between Newton's development of the calculus and Laplace's development of celestial mechanics. One cannot imagine the latter without the former. Today, more than three-quarters of a century has elapsed since the birth of stochastic systems theory. This article provides a perspective on the utilization of systems theory as the proper vehicle for the development of systems biology and its application to complex regulatory diseases such as cancer.
NASA Technical Reports Server (NTRS)
Lee, Jonathan A.
2005-01-01
High-throughput measurement techniques are reviewed for solid phase transformation from materials produced by combinatorial methods, which are highly efficient concepts to fabricate large variety of material libraries with different compositional gradients on a single wafer. Combinatorial methods hold high potential for reducing the time and costs associated with the development of new materials, as compared to time-consuming and labor-intensive conventional methods that test large batches of material, one- composition at a time. These high-throughput techniques can be automated to rapidly capture and analyze data, using the entire material library on a single wafer, thereby accelerating the pace of materials discovery and knowledge generation for solid phase transformations. The review covers experimental techniques that are applicable to inorganic materials such as shape memory alloys, graded materials, metal hydrides, ferric materials, semiconductors and industrial alloys.
Laplace pressure induced droplet generation in micromold for synthesizing monodisperse microspheres.
NASA Astrophysics Data System (ADS)
Choi, Chang-Hyung; Lee, Jinkee; Lee, Chang-Soo
2012-02-01
Microspheres are widely used in applications such MEMS, chemical release systems, optical materials and various biological applications. Here, we report the new micromolding technique for synthesizing spherical monodisperse particles through surface-tension-induced flow. The spherical droplets were prepared using Laplace pressure difference, which is highly depending on geometries of the mold shape, without any pumping system to make flow. We calculated the minimum pressure difference to make the flow moves and form the droplets. It provides a synthetic tool for generating the microspheres using different reaction schemes; UV-polymerization, sol-gel reaction and colloidal assemblies. The monodisperse spherical particles, which are made of various materials, were successfully generated without any surfactant because each droplet can be separately positioned in mold patterns during solidification process.
NASA Astrophysics Data System (ADS)
Djuricic, Ana; Puttonen, Eetu; Harzhauser, Mathias; Dorninger, Peter; Székely, Balázs; Mandic, Oleg; Nothegger, Clemens; Molnár, Gábor; Pfeifer, Norbert
2016-04-01
The world's largest fossilized oyster reef is located in Stetten, Lower Austria excavated during field campaigns of the Natural History Museum Vienna between 2005 and 2008. It is studied in paleontology to learn about change in climate from past events. In order to support this study, a laser scanning and photogrammetric campaign was organized in 2014 for 3D documentation of the large and complex site. The 3D point clouds and high resolution images from this field campaign are visualized by photogrammetric methods in form of digital surface models (DSM, 1 mm resolution) and orthophoto (0.5 mm resolution) to help paleontological interpretation of data. Due to size of the reef, automated analysis techniques are needed to interpret all digital data obtained from the field. One of the key components in successful automation is detection of oyster shell edges. We have tested Reflectance Transformation Imaging (RTI) to visualize the reef data sets for end-users through a cultural heritage viewing interface (RTIViewer). The implementation includes a Lambert shading method to visualize DSMs derived from terrestrial laser scanning using scientific software OPALS. In contrast to shaded RTI no devices consisting of a hardware system with LED lights, or a body to rotate the light source around the object are needed. The gray value for a given shaded pixel is related to the angle between light source and the normal at that position. Brighter values correspond to the slope surfaces facing the light source. Increasing of zenith angle results in internal shading all over the reef surface. In total, oyster reef surface contains 81 DSMs with 3 m x 2 m each. Their surface was illuminated by moving the virtual sun every 30 degrees (12 azimuth angles from 20-350) and every 20 degrees (4 zenith angles from 20-80). This technique provides paleontologists an interactive approach to virtually inspect the oyster reef, and to interpret the shell surface by changing the light source direction
Technology Transfer Automated Retrieval System (TEKTRAN)
Ashe juniper (Juniperus ashei Buchholz), in excessive coverage, reduces forage production, interferes with livestock management, and degrades watersheds and wildlife habitat in infested rangelands. The objective of this study was to apply minimum noise fraction (MNF) transformation and different cla...
Evaluation of EBV transformation of human memory B-cells isolated by FACS and MACS techniques.
Sadreddini, Sanam; Jadidi-Niaragh, Farhad; Younesi, Vahid; Pourlak, Tala; Afkham, Amir; Shokri, Fazel; Yousefi, Mehdi
2016-07-01
Several studies have been performed to develop effective neutralizing monoclonal antibodies. The Epstein-Barr virus (EBV) can efficiently immortalize B-cells to establish lymphoblastoid cell lines (LCL) and so it has been used extensively for transformation of B-cells to produce and secrete immunoglobulin. The present study addressed the effect of TLR7/8 agonist (R848), feeder cells layer and ﬂuorescence-activated cell sorting (FACS) and magnetic-activated cell sorting (MACS) cell separation methods on the transformation efficiency of antibody-producing memory B-cells. For these studies, the antigen used for analyses of antibody formation was the tetanus neurotoxin (TeNT) derived from Clostridium tetani. The results here showed that employing an HFFF.PI6 feeder cell layer, R848 agonist and FACS-mediated purification of memory B-cells led to increased transformation efficiency. Altogether, the effects of the R848 and the feeder cells provided an efficient method for EBV transformation of human B-cells. Moreover, there was an advantage in using FACS sorting of B-cells over the MACS method in the context of EBV transformation and immortalization of precursors of antigen-specific B-cells.
Malanin, M; Eichhorn, K-J; Lederer, A; Treppe, P; Adam, G; Fischer, D; Voigt, D
2009-12-18
Qualitative and quantitative comparison between liquid chromatography (LC) and LC coupled with Fourier transform infrared spectroscopy (LC-FTIR) to evaluate preferential solvation phenomenon of polymers in a mixed solvent has been performed. These studies show that LC-FTIR technique leads to detailed structural information without the requirement for determination of additional parameters for quantitative analysis except calibration. Appropriate experimental conditions for preferential solvation study have been established by variation of polymer concentration, molar mass and eluent content.
Ultra-fast dynamic compression technique to study kinetics of phase transformations in Bismuth
Smith, R F; Kane, J O; Eggert, J H; Saculla, M D; Jankowski, A F; Bastea, M; Hicks, D G; Collins, G W
2007-12-28
Pre-heated Bi was ramp compressed within 30 ns to a peak stress of {approx}11 GPa to explore structural phase transformation kinetics under dynamic loading conditions. Under these ultra-fast compression time-scales the equilibrium Bi I-II phase boundary is overpressurized by {Delta}P {approx} 0.8 GPa. {Delta}P is observed to increase logarithmically with strain rate, {var_epsilon}, above 10{sup 6} s{sup -1}. Estimates from a kinetics model predict that the Bi I phase is fully transformed within 3 ns.
Transformation of Resources to Reserves: Next Generation Heavy-Oil Recovery Techniques
Stanford University; Department of Energy Resources Engineering Green Earth Sciences
2007-09-30
This final report and technical progress report describes work performed from October 1, 2004 through September 30, 2007 for the project 'Transformation of Resources to Reserves: Next Generation Heavy Oil Recovery Techniques', DE-FC26-04NT15526. Critical year 3 activities of this project were not undertaken because of reduced funding to the DOE Oil Program despite timely submission of a continuation package and progress on year 1 and 2 subtasks. A small amount of carried-over funds were used during June-August 2007 to complete some work in the area of foamed-gas mobility control. Completion of Year 3 activities and tasks would have led to a more thorough completion of the project and attainment of project goals. This progress report serves as a summary of activities and accomplishments for years 1 and 2. Experiments, theory development, and numerical modeling were employed to elucidate heavy-oil production mechanisms that provide the technical foundations for producing efficiently the abundant, discovered heavy-oil resources of the U.S. that are not accessible with current technology and recovery techniques. Work fell into two task areas: cold production of heavy oils and thermal recovery. Despite the emerging critical importance of the waterflooding of viscous oil in cold environments, work in this area was never sanctioned under this project. It is envisioned that heavy oil production is impacted by development of an understanding of the reservoir and reservoir fluid conditions leading to so-called foamy oil behavior, i.e, heavy-oil solution gas drive. This understanding should allow primary, cold production of heavy and viscous oils to be optimized. Accordingly, we evaluated the oil-phase chemistry of crude oil samples from Venezuela that give effective production by the heavy-oil solution gas drive mechanism. Laboratory-scale experiments show that recovery correlates with asphaltene contents as well as the so-called acid number (AN) and base number (BN) of the
Caecal perforation from TB and the Law of Laplace
Khan, Amad N.; Khalid, Salema; Chaudhry, Mohammad Naushad; Ho, Cherrie
2015-01-01
A 43-year-old man presented to the hospital with haemoptysis. When worked up, his history and examination were highly suggestive of pulmonary tuberculosis (TB). He subsequently developed a massive upper gastrointestinal bleed and underwent an emergency laparotomy, which revealed a massively dilated caecum measuring ∼20 cm in diameter. The caecum had perforated due to acute decompensation of intestinal TB. Though common in developing countries, TB is rare in the UK, especially the intestinal kind. The most striking feature of this case is, however, the size of the caecal distension caused by the tubercular inflammation and subsequent perforation—something unheard of in the literature. This massive caecal distention would be explained by the Law of Laplace. In conclusion, massive distension and caecal perforation are possible consequences of intestinal TB, especially in the 48–72 h immediately after starting anti-tubercular therapy. PMID:25972412
Laplace-Runge-Lenz vector for arbitrary spin
Nikitin, A. G.
2013-12-15
A countable set of superintegrable quantum mechanical systems is presented which admit the dynamical symmetry with respect to algebra so(4). This algebra is generated by the Laplace-Runge-Lenz vector generalized to the case of arbitrary spin. The presented systems describe neutral particles with non-trivial multipole momenta. Their spectra can be found algebraically like in the case of hydrogen atom. Solutions for the systems with spins 1/2 and 1 are presented explicitly, solutions for spin 3/2 can be expressed via solutions of an ordinary differential equation of first order. A more extended version of this paper including detailed calculations is published as an e-print arXiv:1308.4279.
Numerical implementation of the integral-transform solution to Lamb's point-load problem
NASA Astrophysics Data System (ADS)
Georgiadis, H. G.; Vamvatsikos, D.; Vardoulakis, I.
The present work describes a procedure for the numerical evaluation of the classical integral-transform solution of the transient elastodynamic point-load (axisymmetric) Lamb's problem. This solution involves integrals of rapidly oscillatory functions over semi-infinite intervals and inversion of one-sided (time) Laplace transforms. These features introduce difficulties for a numerical treatment and constitute a challenging problem in trying to obtain results for quantities (e.g. displacements) in the interior of the half-space. To deal with the oscillatory integrands, which in addition may take very large values (pseudo-pole behavior) at certain points, we follow the concept of Longman's method but using as accelerator in the summation procedure a modified Epsilon algorithm instead of the standard Euler's transformation. Also, an adaptive procedure using the Gauss 32-point rule is introduced to integrate in the vicinity of the pseudo-pole. The numerical Laplace-transform inversion is based on the robust Fourier-series technique of Dubner/Abate-Crump-Durbin. Extensive results are given for sub-surface displacements, whereas the limit-case results for the surface displacements compare very favorably with previous exact results.
NASA Astrophysics Data System (ADS)
Petrov, P.; Newman, G. A.
2010-12-01
Quantitative imaging of the subsurface objects is essential part of modern geophysical technology important in oil and gas exploration and wide-range engineering applications. A significant advancement in developing a robust, high resolution imaging technology is concerned with using the different geophysical measurements (gravity, EM and seismic) sense the subsurface structure. A joint image of the subsurface geophysical attributes (velocity, electrical conductivity and density) requires the consistent treatment of the different geophysical data (electromagnetic and seismic) due to their differing physical nature - diffusive and attenuated propagation of electromagnetic energy and nonlinear, multiple scattering wave propagation of seismic energy. Recent progress has been reported in the solution of this problem by reducing the complexity of seismic wave field. Works formed by Shin and Cha (2009 and 2008) suggests that low-pass filtering the seismic trace via Laplace-Fourier transformation can be an effective approach for obtaining seismic data that has similar spatial resolution to EM data. The effect of Laplace- Fourier transformation on the low-pass filtered trace changes the modeling of the seismic wave field from multi-wave propagation to diffusion. The key benefit of transformation is that diffusive wave-field inversion works well for both data sets seismic (Shin and Cha, 2008) and electromagnetic (Commer and Newman 2008, Newman et al., 2010). Moreover the different data sets can also be matched for similar and consistent resolution. Finally, the low pass seismic image is also an excellent choice for a starting model when analyzing the entire seismic waveform to recover the high spatial frequency components of the seismic image; its reflectivity (Shin and Cha, 2009). Without a good starting model full waveform seismic imaging and migration can encounter serious difficulties. To produce seismic wave fields consistent for joint imaging in the Laplace
NASA Astrophysics Data System (ADS)
Kong, Weiwei
2014-03-01
A novel image fusion technique based on NSST (non-subsampled shearlet transform) is presented, aiming at resolving the fusion problem of spatially gray-scale visual light and infrared images. NSST, as a new member of MGA (multi-scale geometric analysis) tools, possesses not only flexible direction features and optimal shift-invariance, but much better fusion performance and lower computational costs compared with several current popular MGA tools such as NSCT (non-subsampled contourlet transform). We specifically propose new rules for the fusion of low and high frequency sub-band coefficients of source images in the second step of the NSST-based image fusion algorithm. First, the source images are decomposed into different scales and directions using NSST. Then, the model of region average energy (RAE) is proposed and adopted to fuse the low frequency sub-band coefficients of the gray-scale visual light and infrared images. Third, the model of local directional contrast (LDC) is given and utilized to fuse the corresponding high frequency sub-band coefficients. Finally, the final fused image is obtained by using inverse NSST to all fused sub-images. In order to verify the effectiveness of the proposed technique, several current popular ones are compared over three different publicly available image sets using four evaluation metrics, and the experimental results demonstrate that the proposed technique performs better in both subjective and objective qualities.
Amin, Hafeez Ullah; Malik, Aamir Saeed; Ahmad, Rana Fayyaz; Badruddin, Nasreen; Kamel, Nidal; Hussain, Muhammad; Chooi, Weng-Tink
2015-03-01
This paper describes a discrete wavelet transform-based feature extraction scheme for the classification of EEG signals. In this scheme, the discrete wavelet transform is applied on EEG signals and the relative wavelet energy is calculated in terms of detailed coefficients and the approximation coefficients of the last decomposition level. The extracted relative wavelet energy features are passed to classifiers for the classification purpose. The EEG dataset employed for the validation of the proposed method consisted of two classes: (1) the EEG signals recorded during the complex cognitive task--Raven's advance progressive metric test and (2) the EEG signals recorded in rest condition--eyes open. The performance of four different classifiers was evaluated with four performance measures, i.e., accuracy, sensitivity, specificity and precision values. The accuracy was achieved above 98 % by the support vector machine, multi-layer perceptron and the K-nearest neighbor classifiers with approximation (A4) and detailed coefficients (D4), which represent the frequency range of 0.53-3.06 and 3.06-6.12 Hz, respectively. The findings of this study demonstrated that the proposed feature extraction approach has the potential to classify the EEG signals recorded during a complex cognitive task by achieving a high accuracy rate.
NASA Astrophysics Data System (ADS)
Emam, Mahmoud; Han, Qi; Yu, Liyang; Zhang, Ye; Niu, Xiamu
2015-07-01
Copy-move is one of the most common methods for image manipulation. Several methods have been proposed to detect and locate the tampered regions, while many methods failed when the copied regions are rotated before being pasted. A rotational invariant detecting method using Polar Complex Exponential Transform (PCET) is proposed in this paper. Firstly, the original image is divided into overlapping circular blocks, and PCET is employed to each block to extract the rotation-invariant robust features. Secondly, the Approximate Nearest Neighbors (ANN) of each feature vector are collected by Locality Sensitive Hashing (LSH). Experimental results show that the proposed technique is robust to rotation.
Ghazali, Nurul Adyani; Ramli, Nor Azam; Yahaya, Ahmad Shukri; Yusof, Noor Faizah Fitri M D; Sansuddin, Nurulilyana; Al Madhoun, Wesam Ahmed
2010-06-01
Analysis and forecasting of air quality parameters are important topics of atmospheric and environmental research today due to the health impact caused by air pollution. This study examines transformation of nitrogen dioxide (NO(2)) into ozone (O(3)) at urban environment using time series plot. Data on the concentration of environmental pollutants and meteorological variables were employed to predict the concentration of O(3) in the atmosphere. Possibility of employing multiple linear regression models as a tool for prediction of O(3) concentration was tested. Results indicated that the presence of NO(2) and sunshine influence the concentration of O(3) in Malaysia. The influence of the previous hour ozone on the next hour concentrations was also demonstrated.
NASA Astrophysics Data System (ADS)
Wei, Mozheng; Toth, Zoltan; Wobus, Richard; Zhu, Yuejian
2008-01-01
Since modern data assimilation (DA) involves the repetitive use of dynamical forecasts, errors in analyses share characteristics of those in short-range forecasts. Initial conditions for an ensemble prediction/forecast system (EPS or EFS) are expected to sample uncertainty in the analysis field. Ensemble forecasts with such initial conditions can therefore (a) be fed back to DA to reduce analysis uncertainty, as well as (b) sample forecast uncertainty related to initial conditions. Optimum performance of both DA and EFS requires a careful choice of initial ensemble perturbations. DA can be improved with an EFS that represents the dynamically conditioned part of forecast error covariance as accurately as possible, while an EFS can be improved by initial perturbations reflecting analysis error variance. Initial perturbation generation schemes that dynamically cycle ensemble perturbations reminiscent to how forecast errors are cycled in DA schemes may offer consistency between DA and EFS, and good performance for both. In this paper, we introduce an EFS based on the initial perturbations that are generated by the Ensemble Transform (ET) and ET with rescaling (ETR) methods to achieve this goal. Both ET and ETR are generalizations of the breeding method (BM). The results from ensemble systems based on BM, ET, ETR and the Ensemble Transform Kalman Filter (ETKF) method are experimentally compared in the context of ensemble forecast performance. Initial perturbations are centred around a 3D-VAR analysis, with a variance equal to that of estimated analysis errors. Of the four methods, the ETR method performed best in most probabilistic scores and in terms of the forecast error explained by the perturbations. All methods display very high time consistency between the analysis and forecast perturbations. It is expected that DA performance can be improved by the use of forecast error covariance from a dynamically cycled ensemble either with a variational DA approach (coupled
Prefabricated vascularized bone flap: a tissue transformation technique for bone reconstruction.
Alam, M I; Asahina, I; Seto, I; Oda, M; Enomoto, S
2001-09-15
In this study, an attempt was made to transform a muscle vascularized pedicle raised on host vessels into a vascularized bone flap, using recombinant human bone morphogenetic protein 2 (rhBMP-2). The purpose of this study was to produce new bone vascularized in nature to increase the survival rate of the subsequently grafted bone and to fabricate the newly formed bone into the desired shape. Silicone molds in the shape of a rat mandible were used to deliver rat bone matrix impregnated with or without rhBMP-2. A muscle pedicle the same size as the mold was raised on the saphenous vessels in the rat thigh and then sandwiched in the center of the silicone molds. The molds were sliced in half and each section was filled with rat bone matrix that was impregnated either with 25 microg of rhBMP-2 for the experimental group or with diluting material alone for the control group. The sandwiched flaps were then secured by tying them to the adjacent muscles and were harvested at 2 and 4 weeks after surgery. Three and six rats were used in the control and experimental groups at each time point, respectively. Bone formation was assessed in the ex vivo specimens by macroscopic, radiologic, and histologic evaluation. Macroscopically, the continuation of the vascular pedicle was clearly visible for both the control and experimental muscle flaps. However, no evidence of muscle-tissue transformation was observed in the control flaps, whereas all the flaps treated with rhBMP-2 produced new bone that replicated the shape of the mold exactly and had saphenous vessels supplying the newly formed bone. This study demonstrates that this experimental model has the potential to be therapeutically applied for effective bone reconstruction.
NASA Astrophysics Data System (ADS)
Hardalupas, Y.; Taylor, A. M. K. P.; Zarogoulidis, K.
2014-08-01
The acquired images of interferometric particle sizing techniques are characterized by intense fringe pattern overlapping in dense droplet and bubble areas, which hinders the image processing process and subsequent information extraction. Methods employed, such as thresholding and the Hough transform and template cross-correlation, exhibit weaknesses when processing such dense areas of interest. We investigate the viability of applying the wavelet transform (WT) for the detection of the fringe pattern centers and the evaluation of the particle size. We present the basics of the WT using the Mexican hat, which exhibits excellent localization properties and present two different alternatives routes in detecting the fringe patterns in the compressed and uncompressed fringe pattern cases. We found that in comparison to the most reported methods for image evaluation, such as intensity thresholding and plain cross-correlation, the WT is a very efficient tool for detecting the patterns, even in images with high-number fringe pattern areas. The usage of the WT for the sizing of the imaged droplets and bubbles is also examined, in comparison to the Fast Fourier Transform (FFT).
Nonparametric identification of structural modifications in Laplace domain
NASA Astrophysics Data System (ADS)
Suwała, G.; Jankowski, Ł.
2017-02-01
This paper proposes and experimentally verifies a Laplace-domain method for identification of structural modifications, which (1) unlike time-domain formulations, allows the identification to be focused on these parts of the frequency spectrum that have a high signal-to-noise ratio, and (2) unlike frequency-domain formulations, decreases the influence of numerical artifacts related to the particular choice of the FFT exponential window decay. In comparison to the time-domain approach proposed earlier, advantages of the proposed method are smaller computational cost and higher accuracy, which leads to reliable performance in more difficult identification cases. Analytical formulas for the first- and second-order sensitivity analysis are derived. The approach is based on a reduced nonparametric model, which has the form of a set of selected structural impulse responses. Such a model can be collected purely experimentally, which obviates the need for design and laborious updating of a parametric model, such as a finite element model. The approach is verified experimentally using a 26-node lab 3D truss structure and 30 identification cases of a single mass modification or two concurrent mass modifications.
Effectiveness of the Young-Laplace equation at nanoscale
Liu, Hailong; Cao, Guoxin
2016-01-01
Using molecular dynamics (MD) simulations, a new approach based on the behavior of pressurized water out of a nanopore (1.3–2.7 nm) in a flat plate is developed to calculate the relationship between the water surface curvature and the pressure difference across water surface. It is found that the water surface curvature is inversely proportional to the pressure difference across surface at nanoscale, and this relationship will be effective for different pore size, temperature, and even for electrolyte solutions. Based on the present results, we cannot only effectively determine the surface tension of water and the effects of temperature or electrolyte ions on the surface tension, but also show that the Young-Laplace (Y-L) equation is valid at nanoscale. In addition, the contact angle of water with the hydrophilic material can be further calculated by the relationship between the critical instable pressure of water surface (burst pressure) and nanopore size. Combining with the infiltration behavior of water into hydrophobic microchannels, the contact angle of water at nanoscale can be more accurately determined by measuring the critical pressure causing the instability of water surface, based on which the uncertainty of measuring the contact angle of water at nanoscale is highly reduced. PMID:27033874
Diffuse-reflectance infrared Fourier transform spectroscopy: new technique of sample preparation
NASA Astrophysics Data System (ADS)
Hrebičík, M.; Budínová, G.; Godarská, T.; Vláčil, D.; Vogenseh, Stine B.; Volka, K.
1997-06-01
A new technique of measurement of the diffuse-reflectance infrared FT spectra, based on the preparation of a cylinder from the mixture of the sample and powdered KBr under pressure of about 5.85 MPa, has been tested. During the measurement, the axis of the formed cylinder is perpendicular to the direction of the incident light. A repeatability of the measurement of selected bands and also of the background was investigated for hydroquinone, nicotinamide, silica gel, rice, tea and also lyophilized human aqueous humour. The relative standard deviations of log( {1}/{R}) showed a dependence on the character of the measured compound, but in general were comparable or slightly better than those obtained by the standard method of loosely packed cups. The values were better than 1.5% in the most cases. The main advantage of the proposed technique lies in its simplicity and rapidity of obtaining statistically significant data.
2007-11-02
J. A. DOWLING , K. M. HAUGHT, R. F. HORTON, S. T. HANLEY, J. A. CURCIO, D. H. GARCIA, AND C. O. GOTT Optical Sciences Division and W. L. AGAMBAR...Spectroscopy, and Gas-Filter Correlation Techniques Personal Author: Dowling , JA.; Haught, K.M.; Horton, R.F; et al. Corporate Author Or Publisher: Naval... Dowling , K. M. Haught, R. F. Horton, S. T. Hanley, J. A. Curcio, D. H. Garcia, and C. 0. Gott Optical Sciences Division and W. L. Agambar
Elmer, J W; Palmer, T A; Zhang, W; DebRoy, T
2005-06-05
Understanding the evolution of microstructure in welds is an important goal of welding research because of the strong correlation between weld microstructure and weld properties. To achieve this goal it is important to develop a quantitative measure of phase transformations encountered during welding in order to ultimately develop methods for predicting weld microstructures from the characteristics of the welding process. To aid in this effort, synchrotron radiation methods have been developed at Lawrence Livermore National Laboratory (LLNL) for direct observation of microstructure evolution during welding. Using intense, highly collimated synchrotron radiation, the atomic structure of the weld heat affected and fusion zones can be probed in real time. Two synchrotron-based techniques, known as spatially resolved (SRXRD) and time resolved (TRXRD) x-ray diffraction, have been developed for these investigations. These techniques have now been used to investigate welding induced phase transformations in titanium alloys, low alloy steels, and stainless steel alloys. This paper will provide a brief overview of these methods and will discuss microstructural evolution during the welding of low carbon (AISI 1005) and medium carbon (AISI 1045) steels where the different levels of carbon influence the evolution of microstructures during welding.
NASA Astrophysics Data System (ADS)
Viles, Heather
2016-10-01
In recent years technological developments have revolutionized our ability to collect data in geomorphology. Enhanced data collection not only enables us to provide deeper answers to a wider range of fundamental questions about the Earth's surface, but also encourages us to pose new questions. This paper considers in more detail the relationships between science, technology and the development of geomorphological tools and techniques, reviews the spectrum of tools and techniques now available to geomorphologists, and critically assesses what impact 'new technologies' are having on geomorphology. It focuses on the role of technology in biogeomorphology and weathering research, and how it is advancing theoretical, empirical and applied dimensions of these growing sub-fields of geomorphology. Five areas of important technological development are reviewed: remote sensing, dating, geophysical techniques, field and laboratory based analysis and sensing of physical and chemical characteristics, and field and laboratory based analysis of biological properties. There is good evidence that, taken together, technological developments are revolutionizing geomorphology through opening the doors to better cross-scalar investigations, blurring the boundaries between laboratory, field and computer model, and facilitating cross-disciplinary and democratized research.
Extremal metrics for eigenvalues of the Laplace-Beltrami operator on surfaces
NASA Astrophysics Data System (ADS)
Penskoi, A. V.
2013-12-01
Known results on geometric optimisation of eigenvalues of the Laplace operator are briefly reviewed, and a more detailed survey of recent results in the theory of extremal metrics on surfaces is presented. Bibliography: 78 titles.
4. Historic American Buildings Survey Drawing by LaPlace VIEW FROM ...
4. Historic American Buildings Survey Drawing by LaPlace VIEW FROM HILL TO REAR OF MISSION GROUNDS - 1839 - Mission San Carlos Borromeo, Rio Road & Lausen Drive, Carmel-by-the-Sea, Monterey County, CA
Tomography of homogenized laser-induced plasma by Radon transform technique
NASA Astrophysics Data System (ADS)
Eschlböck-Fuchs, S.; Demidov, A.; Gornushkin, I. B.; Schmid, T.; Rössler, R.; Huber, N.; Panne, U.; Pedarnig, J. D.
2016-09-01
Tomography of a laser-induced plasma in air is performed by inverse Radon transform of angle-resolved plasma images. Plasmas were induced by single laser pulses (SP), double pulses (DP) in collinear geometry, and by a combination of single laser pulses with pulsed arc discharges (SP-AD). Images of plasmas on metallurgical steel slags were taken at delay times suitable for calibration-free laser-induced breakdown spectroscopy (CF-LIBS). Delays ranged from few microseconds for SP and DP up to tens of microseconds for SP-AD excitation. The white-light and the spectrally resolved emissivity ε(x,y,z) was reconstructed for the three plasma excitation schemes. The electron number density Ne(x,y,z) and plasma temperature Te(x,y,z) were determined from Mg and Mn emission lines in reconstructed spectra employing the Saha-Boltzmann plot method. The SP plasma revealed strongly inhomogeneous emissivity and plasma temperature. Re-excitation of plasma by a second laser pulse (DP) and by an arc discharge (SP-AD) homogenized the plasma and reduced the spatial variation of ε and Te. The homogenization of a plasma is a promising approach to increase the accuracy of calibration-free LIBS analysis of complex materials.
NASA Astrophysics Data System (ADS)
WenQin, Han; Ying, Luo; AiJun, Gu; Yuan, Fuh-Gwo
2016-04-01
Discrimination of acoustic emission (AE) signals related to different damage modes is of great importance in carbon fiber-reinforced plastic (CFRP) composite materials. To gain a deeper understanding of the initiation, growth and evolution of the different types of damage, four types of specimens for different lay-ups and orientations and three types of specimens for interlaminar toughness tests are subjected to tensile test along with acoustic emission monitoring. AE signals have been collected and post-processed, the statistical results show that the peak frequency of AE signal can distinguish various damage modes effectively. After a AE signal were decomposed by Empirical Mode Decomposition (EMD) method, it may separate and extract all damage modes included in this AE signal apart from damage mode corresponding to the peak frequency. Hilbert-Huang Transform (HHT) of AE signals can clearly illustrate the frequency distribution of Intrinsic Mode Functions (IMF) components in time-scale in different damage stages, and can calculate accurate instantaneous frequency for damage modes recognition to help understanding the damage process.
NASA Astrophysics Data System (ADS)
Peng, Rong; Fu, Licai; Zhou, Lingping
2016-12-01
A surface nanocrystalline 1090 steel has been fabricated by using sandblasting technique. The surface average grain size was about 78 nm. The high strain rate and strain in sandblasting were main reasons for surface nanocrystallization. The wear resistance of 1090 steel was considerably enhanced as grain size decreased. The microstructure and hardness of contact zones before and after wear tests have been examined by XRD, SEM and TEM. Except the higher hardness, the results demonstrated that parts of ferrite transferred to cementite and martensite. It was additional beneficial for improving the wear resistance of 1090 steel as the grain size decreased.
Investigation of Laplace barriers for arrayed electrowetting lab-on-a-chip.
Schultz, A; Papautsky, I; Heikenfeld, J
2014-05-13
Partial-post Laplace barriers have been postulated as a means to allow electrowetting transport and geometrical reshaping of fluids, followed by the preservation of fluid geometry after the electrowetting voltage is removed. Reported here is the first investigation of Laplace barriers with the arrayed electrodes and splitting/merging transport functions for an electrowetting lab-on-a-chip. Laplace barriers optimized for 500 × 500 μm(2) electrodes and 78 μm channel height are shown to provide geometrical control of fluid shape down to radii of curvature of ~70 μm. The Laplace barriers increase the splitting volume error, but with proper electrical control, the average error in the split volume is reduced to 5%. Improved programmable fluid storage in droplets or reservoirs and continuous channel flow are also shown. This work confirms the potential benefits of Laplace barriers for lab-on-a-chip and also reveals the unique challenges and operation requirements for Laplace barriers in lab-on-a-chip applications.
Msimanga, Huggins Z; Ollis, Robert J
2010-06-01
Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were used to classify acetaminophen-containing medicines using their attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectra. Four formulations of Tylenol (Arthritis Pain Relief, Extra Strength Pain Relief, 8 Hour Pain Relief, and Extra Strength Pain Relief Rapid Release) along with 98% pure acetaminophen were selected for this study because of the similarity of their spectral features, with correlation coefficients ranging from 0.9857 to 0.9988. Before acquiring spectra for the predictor matrix, the effects on spectral precision with respect to sample particle size (determined by sieve size opening), force gauge of the ATR accessory, sample reloading, and between-tablet variation were examined. Spectra were baseline corrected and normalized to unity before multivariate analysis. Analysis of variance (ANOVA) was used to study spectral precision. The large particles (35 mesh) showed large variance between spectra, while fine particles (120 mesh) indicated good spectral precision based on the F-test. Force gauge setting did not significantly affect precision. Sample reloading using the fine particle size and a constant force gauge setting of 50 units also did not compromise precision. Based on these observations, data acquisition for the predictor matrix was carried out with the fine particles (sieve size opening of 120 mesh) at a constant force gauge setting of 50 units. After removing outliers, PCA successfully classified the five samples in the first and second components, accounting for 45.0% and 24.5% of the variances, respectively. The four-component PLS-DA model (R(2)=0.925 and Q(2)=0.906) gave good test spectra predictions with an overall average of 0.961 +/- 7.1% RSD versus the expected 1.0 prediction for the 20 test spectra used.
NASA Astrophysics Data System (ADS)
Liu, Hua-Long; Liu, Hua-Dong
2014-10-01
Partial discharge (PD) in power transformers is one of the prime reasons resulting in insulation degradation and power faults. Hence, it is of great importance to study the techniques of the detection and localization of PD in theory and practice. The detection and localization of PD employing acoustic emission (AE) techniques, as a kind of non-destructive testing, plus due to the advantages of powerful capability of locating and high precision, have been paid more and more attention. The localization algorithm is the key factor to decide the localization accuracy in AE localization of PD. Many kinds of localization algorithms exist for the PD source localization adopting AE techniques including intelligent and non-intelligent algorithms. However, the existed algorithms possess some defects such as the premature convergence phenomenon, poor local optimization ability and unsuitability for the field applications. To overcome the poor local optimization ability and easily caused premature convergence phenomenon of the fundamental genetic algorithm (GA), a new kind of improved GA is proposed, namely the sequence quadratic programming-genetic algorithm (SQP-GA). For the hybrid optimization algorithm, SQP-GA, the sequence quadratic programming (SQP) algorithm which is used as a basic operator is integrated into the fundamental GA, so the local searching ability of the fundamental GA is improved effectively and the premature convergence phenomenon is overcome. Experimental results of the numerical simulations of benchmark functions show that the hybrid optimization algorithm, SQP-GA, is better than the fundamental GA in the convergence speed and optimization precision, and the proposed algorithm in this paper has outstanding optimization effect. At the same time, the presented SQP-GA in the paper is applied to solve the ultrasonic localization problem of PD in transformers, then the ultrasonic localization method of PD in transformers based on the SQP-GA is proposed. And
Laplace plane modifications arising from solar radiation pressure
Rosengren, Aaron J.; Scheeres, Daniel J.
2014-05-01
The dynamical effects of solar radiation pressure (SRP) in the solar system have been rigorously studied since the early 1900s. This non-gravitational perturbation plays a significant role in the evolution of dust particles in circumplanetary orbits, as well as in the orbital motion about asteroids and comets. For gravitationally dominated orbits, SRP is negligible and the resulting motion is largely governed by the oblateness of the primary and the attraction of the Sun. The interplay between these gravitational perturbations gives rise to three mutually perpendicular planes of equilibrium for circular satellite orbits. The classical Laplace plane lies between the equatorial and orbital planes of the primary, and is the mean reference plane about whose axis the pole of a satellite's orbit precesses. From a previously derived solution for the secular motion of an orbiter about a small body in a SRP dominated environment, we find that SRP acting alone will cause an initially circular orbit to precess around the pole of the primary's heliocentric orbital plane. When the gravitational and non-gravitational perturbations act in concert, the resulting equilibrium planes turn out to be qualitatively different, in some cases, from those obtained without considering the radiation pressure. The warping of the surfaces swept out by the modified equilibria as the semi-major axis varies depends critically on the cross-sectional area of the body exposed. These results, together with an adiabatic invariance argument on Poynting-Robertson drag, provide a natural qualitative explanation for the initial albedo dichotomy of Saturn's moon, Iapetus.
Wang, Gang; Zhang, Xiaofeng; Su, Qingtang; Shi, Jie; Caselli, Richard J.; Wang, Yalin
2015-01-01
Cortical thickness estimation in magnetic resonance imaging (MRI) is an important technique for research on brain development and neurodegenerative diseases. This paper presents a heat kernel based cortical thickness estimation algorithm, which is driven by the graph spectrum and the heat kernel theory, to capture the grey matter geometry information from the in vivo brain magnetic resonance (MR) images. First, we construct a tetrahedral mesh that matches the MR images and reflects the inherent geometric characteristics. Second, the harmonic field is computed by the volumetric Laplace-Beltrami operator and the direction of the steamline is obtained by tracing the maximum heat transfer probability based on the heat kernel diffusion. Thereby we can calculate the cortical thickness information between the point on the pial and white matter surfaces. The new method relies on intrinsic brain geometry structure and the computation is robust and accurate. To validate our algorithm, we apply it to study the thickness differences associated with Alzheimer’s disease (AD) and mild cognitive impairment (MCI) on the Alzheimer’s Disease Neuroimaging Initiative (ADNI) dataset. Our preliminary experimental results on 151 subjects (51 AD, 45 MCI, 55 controls) show that the new algorithm may successfully detect statistically significant difference among patients of AD, MCI and healthy control subjects. Our computational framework is efficient and very general. It has the potential to be used for thickness estimation on any biological structures with clearly defined inner and outer surfaces. PMID:25700360
Emergence of Laplace therapeutics: declaring an end to end-stage heart failure.
Mehra, Mandeep R; Uber, Patricia A
2002-01-01
A large number of chronic heart failure patients escape from the benefits of neurohormonal blockade only to transit into a discouragingly miserable state of what the physician often refers to as end-stage heart failure. Conceptually, the designation of end-stage as a description of a clinical scenario implies pessimism concerning recourse to a therapeutic avenue. A variety of surgical therapeutic techniques that take advantage of the law of Laplace, designed to effectively restore the cardiac shape from a spherical, mechanically inefficient pump to a more elliptical, structurally sound organ are now being employed. Additionally, the field of mechanical device implantation is surging ahead at a rapid pace. The weight of evidence regarding mechanical unloading using assist devices suggests that hemodynamic restoration is accompanied by regression of cellular hypertrophy, normalization of the neuroendocrine axis, improved expression of contractile proteins, enhanced cellular respiratory control, and decreases in markers of apoptosis and cellular stress. Thus, these lines of data point toward discarding the notion of end-stage heart failure. We are at a new crossroad in our quest to tackle chronic heart failure. It is our contention that the use of antiremodeling strategies, including device approaches, will soon signal the end of end-stage heart failure.
Wang, Gang; Zhang, Xiaofeng; Su, Qingtang; Shi, Jie; Caselli, Richard J; Wang, Yalin
2015-05-01
Cortical thickness estimation in magnetic resonance imaging (MRI) is an important technique for research on brain development and neurodegenerative diseases. This paper presents a heat kernel based cortical thickness estimation algorithm, which is driven by the graph spectrum and the heat kernel theory, to capture the gray matter geometry information from the in vivo brain magnetic resonance (MR) images. First, we construct a tetrahedral mesh that matches the MR images and reflects the inherent geometric characteristics. Second, the harmonic field is computed by the volumetric Laplace-Beltrami operator and the direction of the steamline is obtained by tracing the maximum heat transfer probability based on the heat kernel diffusion. Thereby we can calculate the cortical thickness information between the point on the pial and white matter surfaces. The new method relies on intrinsic brain geometry structure and the computation is robust and accurate. To validate our algorithm, we apply it to study the thickness differences associated with Alzheimer's disease (AD) and mild cognitive impairment (MCI) on the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. Our preliminary experimental results on 151 subjects (51 AD, 45 MCI, 55 controls) show that the new algorithm may successfully detect statistically significant difference among patients of AD, MCI and healthy control subjects. Our computational framework is efficient and very general. It has the potential to be used for thickness estimation on any biological structures with clearly defined inner and outer surfaces.
Two Novel Space-Time Coding Techniques Designed for UWB MISO Systems Based on Wavelet Transform
Zaki, Amira Ibrahim; El-Khamy, Said E.
2016-01-01
In this paper two novel space-time coding multi-input single-output (STC MISO) schemes, designed especially for Ultra-Wideband (UWB) systems, are introduced. The proposed schemes are referred to as wavelet space-time coding (WSTC) schemes. The WSTC schemes are based on two types of multiplexing, spatial and wavelet domain multiplexing. In WSTC schemes, four symbols are transmitted on the same UWB transmission pulse with the same bandwidth, symbol duration, and number of transmitting antennas of the conventional STC MISO scheme. The used mother wavelet (MW) is selected to be highly correlated with transmitted pulse shape and such that the multiplexed signal has almost the same spectral characteristics as those of the original UWB pulse. The two WSTC techniques increase the data rate to four times that of the conventional STC. The first WSTC scheme increases the data rate with a simple combination process. The second scheme achieves the increase in the data rate with a less complex receiver and better performance than the first scheme due to the spatial diversity introduced by the structure of its transmitter and receiver. The two schemes use Rake receivers to collect the energy in the dense multipath channel components. The simulation results show that the proposed WSTC schemes have better performance than the conventional scheme in addition to increasing the data rate to four times that of the conventional STC scheme. PMID:27959939
NASA Astrophysics Data System (ADS)
Kong, Weiwei; Wang, Binghe; Lei, Yang
2015-07-01
Fusion of infrared and visible images is an active research area in image processing, and a variety of relevant algorithms have been developed. However, the existing techniques commonly cannot gain good fusion performance and acceptable computational complexity simultaneously. This paper proposes a novel image fusion approach that integrates the non-subsampled shearlet transform (NSST) with spiking cortical model (SCM) to overcome the above drawbacks. On the one hand, using NSST to conduct the decompositions and reconstruction not only consists with human vision characteristics, but also effectively decreases the computational complexity compared with the current popular multi-resolution analysis tools such as non-subsampled contourlet transform (NSCT). On the other hand, SCM, which has been considered to be an optimal neuron network model recently, is responsible for the fusion of sub-images from different scales and directions. Experimental results indicate that the proposed method is promising, and it does significantly improve the fusion quality in both aspects of subjective visual performance and objective comparisons compared with other current popular ones.
NASA Astrophysics Data System (ADS)
Young, Andrew; Marshall, Stephen; Gray, Alison
2016-05-01
The use of aerial hyperspectral imagery for the purpose of remote sensing is a rapidly growing research area. Currently, targets are generally detected by looking for distinct spectral features of the objects under surveillance. For example, a camouflaged vehicle, deliberately designed to blend into background trees and grass in the visible spectrum, can be revealed using spectral features in the near-infrared spectrum. This work aims to develop improved target detection methods, using a two-stage approach, firstly by development of a physics-based atmospheric correction algorithm to convert radiance into re ectance hyperspectral image data and secondly by use of improved outlier detection techniques. In this paper the use of the Percentage Occupancy Hit or Miss Transform is explored to provide an automated method for target detection in aerial hyperspectral imagery.
NASA Astrophysics Data System (ADS)
Olurin, Oluwaseun T.; Ganiyu, Saheed A.; Hammed, Olaide S.; Aluko, Taiwo J.
2016-10-01
This study presents the results of spectral analysis of magnetic data over Abeokuta area, Southwestern Nigeria, using fast Fourier transform (FFT) in Microsoft Excel. The study deals with the quantitative interpretation of airborne magnetic data (Sheet No. 260), which was conducted by the Nigerian Geological Survey Agency in 2009. In order to minimise aliasing error, the aeromagnetic data was gridded at spacing of 1 km. Spectral analysis technique was used to estimate the magnetic basement depth distributed at two levels. The result of the interpretation shows that the magnetic sources are mainly distributed at two levels. The shallow sources (minimum depth) range in depth from 0.103 to 0.278 km below ground level and are inferred to be due to intrusions within the region. The deeper sources (maximum depth) range in depth from 2.739 to 3.325 km below ground and are attributed to the underlying basement.
Mohanan, Sharika; Srivastava, Atul
2014-04-10
The present work is concerned with the development and application of a novel fringe analysis technique based on the principles of the windowed-Fourier-transform (WFT) for the determination of temperature and concentration fields from interferometric images for a range of heat and mass transfer applications. Based on the extent of the noise level associated with the experimental data, the technique has been coupled with two different phase unwrapping methods: the Itoh algorithm and the quality guided phase unwrapping technique for phase extraction. In order to generate the experimental data, a range of experiments have been carried out which include cooling of a vertical flat plate in free convection conditions, combustion of mono-propellant flames, and growth of organic as well as inorganic crystals from their aqueous solutions. The flat plate and combustion experiments are modeled as heat transfer applications wherein the interest is to determine the whole-field temperature distribution. Aqueous-solution-based crystal growth experiments are performed to simulate the mass transfer phenomena and the interest is to determine the two-dimensional solute concentration field around the growing crystal. A Mach-Zehnder interferometer has been employed to record the path-integrated quantity of interest (temperature and/or concentration) in the form of interferometric images in the experiments. The potential of the WFT method has also been demonstrated on numerically simulated phase data for varying noise levels, and the accuracy in phase extraction have been quantified in terms of the root mean square errors. Three levels of noise, i.e., 0%, 10%, and 20% have been considered. Results of the present study show that the WFT technique allows an accurate extraction of phase values that can subsequently be converted into two-dimensional temperature and/or concentration distribution fields. Moreover, since WFT is a local processing technique, speckle patterns and the inherent
Julià, Olga; Vidal-Mas, Jaume; Panikov, Nicolai S; Vives-Rego, Josep
2010-01-01
We report a skew-Laplace statistical analysis of both flow cytometry scatters and cell size from microbial strains primarily grown in batch cultures, others in chemostat cultures and bacterial aquatic populations. Cytometry scatters best fit the skew-Laplace distribution while cell size as assessed by an electronic particle analyzer exhibited a moderate fitting. Unlike the cultures, the aquatic bacterial communities clearly do not fit to a skew-Laplace distribution. Due to its versatile nature, the skew-Laplace distribution approach offers an easy, efficient, and powerful tool for distribution of frequency analysis in tandem with the flow cytometric cell sorting.
Julià, Olga; Vidal-Mas, Jaume; Panikov, Nicolai S.; Vives-Rego, Josep
2010-01-01
We report a skew-Laplace statistical analysis of both flow cytometry scatters and cell size from microbial strains primarily grown in batch cultures, others in chemostat cultures and bacterial aquatic populations. Cytometry scatters best fit the skew-Laplace distribution while cell size as assessed by an electronic particle analyzer exhibited a moderate fitting. Unlike the cultures, the aquatic bacterial communities clearly do not fit to a skew-Laplace distribution. Due to its versatile nature, the skew-Laplace distribution approach offers an easy, efficient, and powerful tool for distribution of frequency analysis in tandem with the flow cytometric cell sorting. PMID:20592754
On the Analytical and Numerical Properties of the Truncated Laplace Transform I
2014-09-05
for example, [1]) . The Singular Value Decomposition (SVD) of La,b has been analyzed, inter alia, in [1] and [9]; Bertero and Grünbaum observed that...1 . (19) By (6), (16), (18) and (17),∫ 1 0 (x+ y)−1P ∗k (x)dx = 2(−1) kQ∗k(y + 1) √ 2k + 1 (20) for all y > 0. 4 2.3 Singular Value Decomposition ...SVD) of integral operators The Singular Value Decomposition (SVD) of integral operators and its key properties are summarized in the following theorem
LaPlace Transform1 Adaptive Control Law in Support of Large Flight Envelope Modeling Work
NASA Technical Reports Server (NTRS)
Gregory, Irene M.; Xargay, Enric; Cao, Chengyu; Hovakimyan, Naira
2011-01-01
This paper presents results of a flight test of the L1 adaptive control architecture designed to directly compensate for significant uncertain cross-coupling in nonlinear systems. The flight test was conducted on the subscale turbine powered Generic Transport Model that is an integral part of the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. The results presented are in support of nonlinear aerodynamic modeling and instrumentation calibration.
A Method of Evaluating Laplace Transforms with Series of Complete or Incomplete Beta Functions,
1982-12-01
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The Masked Sample Covariance Estimator: An Analysis via the Matrix Laplace Transform
2012-02-01
A. TROPP Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to...completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of ...Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person
Ultrafast multidimensional Laplace NMR for a rapid and sensitive chemical analysis
NASA Astrophysics Data System (ADS)
Ahola, Susanna; Zhivonitko, Vladimir V.; Mankinen, Otto; Zhang, Guannan; Kantola, Anu M.; Chen, Hsueh-Ying; Hilty, Christian; Koptyug, Igor V.; Telkki, Ville-Veikko
2015-09-01
Traditional nuclear magnetic resonance (NMR) spectroscopy relies on the versatile chemical information conveyed by spectra. To complement conventional NMR, Laplace NMR explores diffusion and relaxation phenomena to reveal details on molecular motions. Under a broad concept of ultrafast multidimensional Laplace NMR, here we introduce an ultrafast diffusion-relaxation correlation experiment enhancing the resolution and information content of corresponding 1D experiments as well as reducing the experiment time by one to two orders of magnitude or more as compared with its conventional 2D counterpart. We demonstrate that the method allows one to distinguish identical molecules in different physical environments and provides chemical resolution missing in NMR spectra. Although the sensitivity of the new method is reduced due to spatial encoding, the single-scan approach enables one to use hyperpolarized substances to boost the sensitivity by several orders of magnitude, significantly enhancing the overall sensitivity of multidimensional Laplace NMR.
NASA Astrophysics Data System (ADS)
Majić, Matt R. A.; Auguié, Baptiste; Le Ru, Eric C.
2017-03-01
We propose a powerful approach to solve Laplace's equation for point sources near a spherical object. The central new idea is to use prolate spheroidal solid harmonics, which are separable solutions of Laplace's equation in spheroidal coordinates, instead of the more natural spherical solid harmonics. Using electrostatics as an example, we motivate this choice and show that the resulting series expansions converge much faster. This improvement is discussed in terms of the singularity of the solution and its analytic continuation. The benefits of this approach are further illustrated for a specific example: the calculation of modified decay rates of light emitters close to nanostructures in the quasistatic approximation. We expect the general approach to be applicable with similar benefits to the solution of Laplace's equation for other geometries and to other equations of mathematical physics.
Regularized Laplace-Fourier-Domain Full Waveform Inversion Using a Weighted l 2 Objective Function
NASA Astrophysics Data System (ADS)
Jun, Hyunggu; Kwon, Jungmin; Shin, Changsoo; Zhou, Hongbo; Cogan, Mike
2017-03-01
Full waveform inversion (FWI) can be applied to obtain an accurate velocity model that contains important geophysical and geological information. FWI suffers from the local minimum problem when the starting model is not sufficiently close to the true model. Therefore, an accurate macroscale velocity model is essential for successful FWI, and Laplace-Fourier-domain FWI is appropriate for obtaining such a velocity model. However, conventional Laplace-Fourier-domain FWI remains an ill-posed and ill-conditioned problem, meaning that small errors in the data can result in large differences in the inverted model. This approach also suffers from certain limitations related to the logarithmic objective function. To overcome the limitations of conventional Laplace-Fourier-domain FWI, we introduce a weighted l 2 objective function, instead of the logarithmic objective function, as the data-domain objective function, and we also introduce two different model-domain regularizations: first-order Tikhonov regularization and prior model regularization. The weighting matrix for the data-domain objective function is constructed to suitably enhance the far-offset information. Tikhonov regularization smoothes the gradient, and prior model regularization allows reliable prior information to be taken into account. Two hyperparameters are obtained through trial and error and used to control the trade-off and achieve an appropriate balance between the data-domain and model-domain gradients. The application of the proposed regularizations facilitates finding a unique solution via FWI, and the weighted l 2 objective function ensures a more reasonable residual, thereby improving the stability of the gradient calculation. Numerical tests performed using the Marmousi synthetic dataset show that the use of the weighted l 2 objective function and the model-domain regularizations significantly improves the Laplace-Fourier-domain FWI. Because the Laplace-Fourier-domain FWI is improved, the
Regularized Laplace-Fourier-Domain Full Waveform Inversion Using a Weighted l 2 Objective Function
NASA Astrophysics Data System (ADS)
Jun, Hyunggu; Kwon, Jungmin; Shin, Changsoo; Zhou, Hongbo; Cogan, Mike
2016-09-01
Full waveform inversion (FWI) can be applied to obtain an accurate velocity model that contains important geophysical and geological information. FWI suffers from the local minimum problem when the starting model is not sufficiently close to the true model. Therefore, an accurate macroscale velocity model is essential for successful FWI, and Laplace-Fourier-domain FWI is appropriate for obtaining such a velocity model. However, conventional Laplace-Fourier-domain FWI remains an ill-posed and ill-conditioned problem, meaning that small errors in the data can result in large differences in the inverted model. This approach also suffers from certain limitations related to the logarithmic objective function. To overcome the limitations of conventional Laplace-Fourier-domain FWI, we introduce a weighted l 2 objective function, instead of the logarithmic objective function, as the data-domain objective function, and we also introduce two different model-domain regularizations: first-order Tikhonov regularization and prior model regularization. The weighting matrix for the data-domain objective function is constructed to suitably enhance the far-offset information. Tikhonov regularization smoothes the gradient, and prior model regularization allows reliable prior information to be taken into account. Two hyperparameters are obtained through trial and error and used to control the trade-off and achieve an appropriate balance between the data-domain and model-domain gradients. The application of the proposed regularizations facilitates finding a unique solution via FWI, and the weighted l 2 objective function ensures a more reasonable residual, thereby improving the stability of the gradient calculation. Numerical tests performed using the Marmousi synthetic dataset show that the use of the weighted l 2 objective function and the model-domain regularizations significantly improves the Laplace-Fourier-domain FWI. Because the Laplace-Fourier-domain FWI is improved, the
Tidal Friction in the Earth-Moon System and Laplace Planes: Darwin Redux
NASA Technical Reports Server (NTRS)
Rubincam, David P.
2015-01-01
The dynamical evolution of the Earth-Moon system due to tidal friction is treated here. George H. Darwin used Laplace planes (also called proper planes) in his study of tidal evolution. The Laplace plane approach is adapted here to the formalisms of W.M. Kaula and P. Goldreich. Like Darwin, the approach assumes a three-body problem: Earth, Moon, and Sun, where the Moon and Sun are point-masses. The tidal potential is written in terms of the Laplace plane angles. The resulting secular equations of motion can be easily integrated numerically assuming the Moon is in a circular orbit about the Earth and the Earth is in a circular orbit about the Sun. For Earth-Moon distances greater than 10 Earth radii, the Earth's approximate tidal response can be characterized with a single parameter, which is a ratio: a Love number times the sine of a lag angle divided by another such product. For low parameter values it can be shown that Darwin's low-viscosity molten Earth, M. Ross's and G. Schubert's model of an Earth near melting, and Goldreich's equal tidal lag angles must all give similar histories. For higher parameter values, as perhaps has been the case at times with the ocean tides, the Earth's obliquity may have decreased slightly instead of increased once the Moon's orbit evolved further than 50 Earth radii from the Earth, with possible implications for climate. This is contrast to the other tidal friction models mentioned, which have the obliquity always increasing with time. As for the Moon, its orbit is presently tilted to its Laplace plane by 5.2deg. The equations do not allow the Moon to evolve out of its Laplace plane by tidal friction alone, so that if it was originally in its Laplace plane, the tilt arose with the addition of other mechanisms, such as resonance passages.
Tidal friction in the Earth-Moon system and Laplace planes: Darwin redux
NASA Astrophysics Data System (ADS)
Rubincam, David Parry
2016-03-01
The dynamical evolution of the Earth-Moon system due to tidal friction is treated here. George H. Darwin used Laplace planes (also called proper planes) in his study of tidal evolution. The Laplace plane approach is adapted here to the formalisms of W.M. Kaula and P. Goldreich. Like Darwin, the approach assumes a three-body problem: Earth, Moon, and Sun, where the Moon and Sun are point-masses. The tidal potential is written in terms of the Laplace plane angles. The resulting secular equations of motion can be easily integrated numerically assuming the Moon is in a circular orbit about the Earth and the Earth is in a circular orbit about the Sun. For Earth-Moon distances greater than ∼10 Earth radii, the Earth's approximate tidal response can be characterized with a single parameter, which is a ratio: a Love number times the sine of a lag angle divided by another such product. For low parameter values it can be shown that Darwin's low-viscosity molten Earth, M. Ross's and G. Schubert's model of an Earth near melting, and Goldreich's equal tidal lag angles must all give similar histories. For higher parameter values, as perhaps has been the case at times with the ocean tides, the Earth's obliquity may have decreased slightly instead of increased once the Moon's orbit evolved further than 50 Earth radii from the Earth, with possible implications for climate. This is contrast to the other tidal friction models mentioned, which have the obliquity always increasing with time. As for the Moon, its orbit is presently tilted to its Laplace plane by 5.2°. The equations do not allow the Moon to evolve out of its Laplace plane by tidal friction alone, so that if it was originally in its Laplace plane, the tilt arose with the addition of other mechanisms, such as resonance passages.
NASA Technical Reports Server (NTRS)
Thornhill, K. Lee; Bitting, Herbert; Lee, Robert B., III; Paden, Jack; Pandey, Dhirendra K.; Priestley, Kory J.; Thomas, Susan; Wilson, Robert S.
1998-01-01
Fourier Transform Spectrometer (FTS) techniques are being used to characterize the relative spectral response, or sensitivity, of scanning thermistor bolometers in the infrared (IR) region (2 - >= 100-micrometers). The bolometers are being used in the Clouds and the Earth's Radiant Energy System (CERES) program. The CERES measurements are designed to provide precise, long term monitoring of the Earth's atmospheric radiation energy budget. The CERES instrument houses three bolometric radiometers, a total wavelength (0.3- >= 150-micrometers) sensor, a shortwave (0.3-5-micrometers) sensor, and an atmospheric window (8-12-micrometers) sensor. Accurate spectral characterization is necessary for determining filtered radiances for longwave radiometric calibrations. The CERES bolometers spectral response's are measured in the TRW FTS Vacuum Chamber Facility (FTS - VCF), which uses a FTS as the source and a cavity pyroelectric trap detector as the reference. The CERES bolometers and the cavity detector are contained in a vacuum chamber, while the FTS source is housed in a GN2 purged chamber. Due to the thermal time constant of the CERES bolometers, the FTS must be operated in a step mode. Data are acquired in 6 IR spectral bands covering the entire longwave IR region. In this paper, the TRW spectral calibration facility design and data measurement techniques are described. Two approaches are presented which convert the total channel FTS data into the final CERES spectral characterizations, producing the same calibration coefficients (within 0.1 percent). The resulting spectral response curves are shown, along with error sources in the two procedures. Finally, the impact of each spectral response curve on CERES data validation will be examined through analysis of filtered radiance values from various typical scene types.
NASA Technical Reports Server (NTRS)
Uritskiy, Vadim M.; Davila, Joseph M.; Viall, Nicholeen M.; Ofman, Leon
2013-01-01
A set of co-aligned high resolution images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) is used to investigate propagating disturbances (PDs) in warm fan loops at the periphery of a non-flaring active region NOAA AR 11082. To measure PD speeds at multiple coronal temperatures, a new data analysis methodology is proposed enabling quantitative description of sub visual coronal motions with low signal-to-noise ratios of the order of 0.1. The technique operates with a set of one-dimensional surfing signals extracted from position-timeplots of several AIA channels through a modified version of Radon transform. The signals are used to evaluate a two-dimensional power spectral density distribution in the frequency - velocity space which exhibits a resonance in the presence of quasi-periodic PDs. By applying this analysis to the same fan loop structures observed in several AIA channels, we found that the traveling velocity of PDs increases with the temperature of the coronal plasma following the square root dependence predicted for the slow mode magneto-acoustic wave which seems to be the dominating wave mode in the studied loop structures. This result extends recent observations by Kiddie et al. (2012) to a more general class of fan loop systems not associated with sunspots and demonstrating consistent slow mode activity in up to four AIA channels.
NASA Astrophysics Data System (ADS)
González, M. A.; Frick, B.
IN16 is a backscattering spectrometer combining high flux and an excellent resolution. We have studied a possibility to improve both the flux and the dynamic range of this instrument by using the phase space transformation technique to monochromatize a white neutron beam. By using a crystal mounted on a chopper that moves perpendicularly to the average scattering vector of the incident neutrons, it is possible to increase significantly the number of neutrons in a given wavelength band at the expense of worsening the Q resolution. In order to obtain reliable information about the improvement that could be achieved by applying this principle to the existing instrument, we have performed simulations with the McStas package to compare the flux of IN16 in its present configuration with that of an hypothetical IN16B located at the end position of a straight focusing neutron guide. The simulations reproduce well several test experiments performed on IN16 and allow us to predict that a gain in flux of about an order of magnitude can be expected.
Laplace-Gauss and Helmholtz-Gauss paraxial modes in media with quadratic refraction index.
Kiselev, Aleksei P; Plachenov, Alexandr B
2016-04-01
The scalar theory of paraxial wave propagation in an axisymmetric medium where the refraction index quadratically depends on transverse variables is addressed. Exact solutions of the corresponding parabolic equation are presented, generalizing the Laplace-Gauss and Helmholtz-Gauss modes earlier known for homogeneous media. Also, a generalization of a zero-order asymmetric Bessel-Gauss beam is given.
On a class of nonlocal boundary value problems for the Laplace operator in a disk
NASA Astrophysics Data System (ADS)
Sadybekov, Makhmud; Torebek, Berikbol
2016-12-01
In this work we consider a nonlocal boundary value problem for the Laplace operator in a disk. A Newton potential is a particular case of the problem. We establish conditions of its Noetherian property, Fredholm property and well-posedness. We prove self-adjointness of the problem. We construct all the eigenvalues and eigenfunctions of the problem for a correct case.
The kernel of Laplace-Beltrami operators with zero-radius potential or on decorated graphs
NASA Astrophysics Data System (ADS)
Tolchennikov, A. A.
2008-08-01
An isomorphism is described for the kernel of the Laplace operator \\Delta^{\\!\\Lambda} (determined by a Lagrangian plane \\Lambda\\subset\\mathbb C^k\\oplus\\mathbb C^k) with potential \\sum_{j=1}^kc_j\\delta_{q_j}(x) on a manifold. The isomorphism is given by \\Gamma\\colon\\ker\\Delta^{\\!\\Lambda}\\to\\Lambda\\cap\
New modification of Laplace decomposition method for seventh order KdV equation
NASA Astrophysics Data System (ADS)
Kashkari, B. S.; Bakodah, H. O.
2013-10-01
In this paper, we develop a new modification of Laplace decomposition method for solving the seventh order KdV equations. The numerical results show that the method converges rapidly and compared with the Adomian decomposition method. The conservation properties of solution are examined by calculating the first three invariants.
Extensivity of Rényi entropy for the Laplace-de Finetti distribution
NASA Astrophysics Data System (ADS)
Bergeron, H.; Curado, E. M. F.; Gazeau, J. P.; Rodrigues, Ligia M. C. S.
2016-01-01
The Boltzmann-Gibbs entropy is known to be asymptotically extensive for the Laplace-de Finetti distribution. We prove here that the same result holds in the case of the Rényi entropy. We also show some interesting lower and upper bounds for the asymptotic limit of these entropies.
An evolution infinity Laplace equation modelling dynamic elasto-plastic torsion
NASA Astrophysics Data System (ADS)
Messelmi, Farid
2016-09-01
We consider in this paper a parabolic partial differential equation involving the infinity Laplace operator and a Leray-Lions operator with no coercitive assumption. We prove the existence and uniqueness of the corresponding approached problem and we show that at the limit the solution solves the parabolic variational inequality arising in the elasto-plastic torsion problem.
Existence results for degenerate p(x)-Laplace equations with Leray-Lions type operators
NASA Astrophysics Data System (ADS)
Ho, Ky; Sim, Inbo
2017-01-01
We show the various existence results for degenerate $p(x)$-Laplace equations with Leray-Lions type operators. A suitable condition on degeneracy is discussed and proofs are mainly based on direct methods and critical point theories in Calculus of Variations. In particular, we investigate the various situations of the growth rates between principal operators and nonlinearities.
Cluster analysis of European Y-chromosomal STR haplotypes using the discrete Laplace method.
Andersen, Mikkel Meyer; Eriksen, Poul Svante; Morling, Niels
2014-07-01
The European Y-chromosomal short tandem repeat (STR) haplotype distribution has previously been analysed in various ways. Here, we introduce a new way of analysing population substructure using a new method based on clustering within the discrete Laplace exponential family that models the probability distribution of the Y-STR haplotypes. Creating a consistent statistical model of the haplotypes enables us to perform a wide range of analyses. Previously, haplotype frequency estimation using the discrete Laplace method has been validated. In this paper we investigate how the discrete Laplace method can be used for cluster analysis to further validate the discrete Laplace method. A very important practical fact is that the calculations can be performed on a normal computer. We identified two sub-clusters of the Eastern and Western European Y-STR haplotypes similar to results of previous studies. We also compared pairwise distances (between geographically separated samples) with those obtained using the AMOVA method and found good agreement. Further analyses that are impossible with AMOVA were made using the discrete Laplace method: analysis of the homogeneity in two different ways and calculating marginal STR distributions. We found that the Y-STR haplotypes from e.g. Finland were relatively homogeneous as opposed to the relatively heterogeneous Y-STR haplotypes from e.g. Lublin, Eastern Poland and Berlin, Germany. We demonstrated that the observed distributions of alleles at each locus were similar to the expected ones. We also compared pairwise distances between geographically separated samples from Africa with those obtained using the AMOVA method and found good agreement.
Lemery, F.; Mihalcea, D.; Prokop, C.R.; Piot, P.; /Northern Illinois U. /Fermilab
2012-07-08
In recent years, wakefield acceleration has gained attention due to its high acceleration gradients and cost effectiveness. In beam-driven wakefield acceleration, a critical parameter to optimize is the transformer ratio. It has been shown that current shaping of electron beams allows for enhanced (> 2) transformer ratios. In this paper we present the optimization of the pulse shape of the drive bunch for dielectric-wakefield acceleration.
Yamauchi, M; Okubo, K; Tsukuda, T; Kato, K; Takata, M; Takeda, S
2014-04-21
In situ X-ray diffraction measurements reveal that the transformation of a AuCu nanoalloy from a face-centered-cubic to an L10 structure is accelerated under a hydrogen atmosphere. The structural transformation rate for the AuCu nanoalloy under hydrogen above 433 K was found to be 100 times faster than that in a vacuum, which is the first quantitative observation of hydrogen-induced ordering of nanoalloys.
Chai, Jyh-Wen; Chen, Clayton C; Wu, Yi-Ying; Chen, Hung-Chieh; Tsai, Yi-Hsin; Chen, Hsian-Min; Lan, Tsuo-Hung; Ouyang, Yen-Chieh; Lee, San-Kan
2015-01-01
A new TRIO algorithm method integrating three different algorithms is proposed to perform brain MRI segmentation in the native coordinate space, with no need of transformation to a standard coordinate space or the probability maps for segmentation. The method is a simple voxel-based algorithm, derived from multispectral remote sensing techniques, and only requires minimal operator input to depict GM, WM, and CSF tissue clusters to complete classification of a 3D high-resolution multislice-multispectral MRI data. Results showed very high accuracy and reproducibility in classification of GM, WM, and CSF in multislice-multispectral synthetic MRI data. The similarity indexes, expressing overlap between classification results and the ground truth, were 0.951, 0.962, and 0.956 for GM, WM, and CSF classifications in the image data with 3% noise level and 0% non-uniformity intensity. The method particularly allows for classification of CSF with 0.994, 0.961 and 0.996 of accuracy, sensitivity and specificity in images data with 3% noise level and 0% non-uniformity intensity, which had seldom performed well in previous studies. As for clinical MRI data, the quantitative data of brain tissue volumes aligned closely with the brain morphometrics in three different study groups of young adults, elderly volunteers, and dementia patients. The results also showed very low rates of the intra- and extra-operator variability in measurements of the absolute volumes and volume fractions of cerebral GM, WM, and CSF in three different study groups. The mean coefficients of variation of GM, WM, and CSF volume measurements were in the range of 0.03% to 0.30% of intra-operator measurements and 0.06% to 0.45% of inter-operator measurements. In conclusion, the TRIO algorithm exhibits a remarkable ability in robust classification of multislice-multispectral brain MR images, which would be potentially applicable for clinical brain volumetric analysis and explicitly promising in cross
Transverse colon perforation due to carcinoma rectum: an unusual presentation against Laplace's law.
Sahoo, Manash Ranjan; Kumar, Anil; Jaiswal, Sunil; C, Basavaraja
2013-08-16
We present a case of distal large bowel obstruction, in the setting of a competent ileocaecal valve, the caecum is the most common site of perforation (for Laplace's law). We describe a case of obstruction at the rectum due to constricting carcinomatous growth, presenting with perforation of transverse colon (against Laplace's law). A 60-year-old women presented to the emergency department with acute abdominal pain. The pain was preceded by 3 days of intestinal obstruction. Clinically there was guarding and rigidity. Straight X-ray of the abdomen revealed free gas under diaphragm. Surgical exploration revealed transverse colon perforation with carcinoma of rectum. Loop transverse colostomy was performed as the patient was very sick. The patient improved slowly in the intensive care unit. To conclude, even though the caecum is the most common site for perforation in case of distal obstruction, perforation of transverse colon can occur otherwise as a unique presentation.
High resolution Laplace DLTS studies of defects in ion-implanted silicon
NASA Astrophysics Data System (ADS)
Evans-Freeman, J. H.; Abdelgader, N.; Kan, P. Y. Y.; Peaker, A. R.
2002-01-01
We have used high resolution Laplace deep level transient spectroscopy (LDLTS) to investigate defects in n-type silicon caused by implantation of Si, Ge or Er with doses of the order of 1×10 9 cm-2. These are compared with defects created in proton irradiated n-type silicon. Unlike the simple proton irradiated case, LDLTS spectra of ion implanted silicon show that there are many emission rates associated with defects with energies in the region of Ec-400 meV. We have carried out annealing studies and Laplace DLTS depth profiling and show that the complex spectra measured from a region less than half way through the implant simplify as the profile is moved through the implant and towards the tail. Annealing studies show that these defects survive an anneal that should remove the E-centre.
Research on temporal features of LEMP based on Laplace wavelet in time and frequency domain
NASA Astrophysics Data System (ADS)
Li, Qin; Zhong, Jianwei; Ai, Qing; Gao, Shihong
2015-12-01
In this paper, the fine-structures of lightning electromagnetic pulse (LEMP) including 19 pulses in preliminary breakdown, 37 stepped leaders, 8 dart leaders, 73 first return strokes, and 52 subsequent return strokes have been analyzed based on Laplace wavelet. The main characteristics of field waveforms are presented: the correlation coefficient, the dominant frequency, the peak energy and the spread distribution of the power spectrum. The instantaneous field peak pulse can be precisely located by the value of the correlation coefficient. The pulses of preliminary breakdown and leaders are found to radiate in the dominant frequency in the range 100 kHz to 1 MHz. The field radiated by the first return strokes dominantly lies under 100 kHz, whereas the subsequent return strokes under 50 kHz. The statistical results show that the Laplace wavelet is effective and can accurately determine time and frequency of the electromagnetic field of first and subsequent return strokes.
The local counting function of operators of Dirac and Laplace type
NASA Astrophysics Data System (ADS)
Li, Liangpan; Strohmaier, Alexander
2016-06-01
Let P be a non-negative self-adjoint Laplace type operator acting on sections of a hermitian vector bundle over a closed Riemannian manifold. In this paper we review the close relations between various P-related coefficients such as the mollified spectral counting coefficients, the heat trace coefficients, the resolvent trace coefficients, the residues of the spectral zeta function as well as certain Wodzicki residues. We then use the Wodzicki residue to obtain results about the local counting function of operators of Dirac and Laplace type. In particular, we express the second term of the mollified spectral counting function of Dirac type operators in terms of geometric quantities and characterize those Dirac type operators for which this coefficient vanishes.
Tests of Fit for Asymmetric Laplace Distributions with Applications on Financial Data
NASA Astrophysics Data System (ADS)
Fragiadakis, Kostas; Meintanis, Simos G.
2008-11-01
New goodness-of-fit tests for the family of asymmetric Laplace distributions are constructed. The proposed tests are based on a weighted integral incorporating the empirical characteristic function of suitably standardized data, and can be written in a closed form appropriate for computer implementation. Monte Carlo results show that the new procedure are competitive with classical goodness-of-fit methods. Applications with financial data are also included.
I termini di Cassini e Laplace della rifrazione atmosferica misurati alla Meridiana Clementina
NASA Astrophysics Data System (ADS)
Sigismondi, Costantino
2016-05-01
The measures of the atmospheric refraction terms of Cassini and Laplace are made at the Clementine Meridian Line of S. Maria degli Angeli in Rome by comparing the observed positions of the center of the Sun with the ones calculated without atmosphere. Three linear systems with the data of 21 Dec 2015; 18 Jan and 6 Feb 2016 give the refraction terms of tan(z) and tan3(z).
Operation Plumbbob. Program 2. Neutron and gamma radiation from Shot Laplace
Chiment, J.A.; Goetz, J.L.; Facer, G.C.
1984-10-31
The objectives of this experiment were to determine, for Shot Laplace, a 1.22-kt device fired late in Operation Plumbbob: (1) intensity and decay of the neuron-induced gammafield; (2) neutron flux and spectra as a function of distance; (3) neutron flux as a function of soil depth with certain selected detectors; and (4) neutron dose and initial gamma dose as a function of distance.
ERIC Educational Resources Information Center
Nguyen, Roselynn H.; Null, J. Wesley
2008-01-01
Upon reviewing the story of higher education from the early eighteenth to the late twentieth century, the authors are able to evaluate the ideals of knowledge and how they have been transformed during this time period. Considering the implications education has on the training of students who become leaders in society, individuals should pay…
Shao, Yan-Lin Faltinsen, Odd M.
2014-10-01
We propose a new efficient and accurate numerical method based on harmonic polynomials to solve boundary value problems governed by 3D Laplace equation. The computational domain is discretized by overlapping cells. Within each cell, the velocity potential is represented by the linear superposition of a complete set of harmonic polynomials, which are the elementary solutions of Laplace equation. By its definition, the method is named as Harmonic Polynomial Cell (HPC) method. The characteristics of the accuracy and efficiency of the HPC method are demonstrated by studying analytical cases. Comparisons will be made with some other existing boundary element based methods, e.g. Quadratic Boundary Element Method (QBEM) and the Fast Multipole Accelerated QBEM (FMA-QBEM) and a fourth order Finite Difference Method (FDM). To demonstrate the applications of the method, it is applied to some studies relevant for marine hydrodynamics. Sloshing in 3D rectangular tanks, a fully-nonlinear numerical wave tank, fully-nonlinear wave focusing on a semi-circular shoal, and the nonlinear wave diffraction of a bottom-mounted cylinder in regular waves are studied. The comparisons with the experimental results and other numerical results are all in satisfactory agreement, indicating that the present HPC method is a promising method in solving potential-flow problems. The underlying procedure of the HPC method could also be useful in other fields than marine hydrodynamics involved with solving Laplace equation.
Laplace-domain waveform modeling and inversion for the 3D acoustic-elastic coupled media
NASA Astrophysics Data System (ADS)
Shin, Jungkyun; Shin, Changsoo; Calandra, Henri
2016-06-01
Laplace-domain waveform inversion reconstructs long-wavelength subsurface models by using the zero-frequency component of damped seismic signals. Despite the computational advantages of Laplace-domain waveform inversion over conventional frequency-domain waveform inversion, an acoustic assumption and an iterative matrix solver have been used to invert 3D marine datasets to mitigate the intensive computing cost. In this study, we develop a Laplace-domain waveform modeling and inversion algorithm for 3D acoustic-elastic coupled media by using a parallel sparse direct solver library (MUltifrontal Massively Parallel Solver, MUMPS). We precisely simulate a real marine environment by coupling the 3D acoustic and elastic wave equations with the proper boundary condition at the fluid-solid interface. In addition, we can extract the elastic properties of the Earth below the sea bottom from the recorded acoustic pressure datasets. As a matrix solver, the parallel sparse direct solver is used to factorize the non-symmetric impedance matrix in a distributed memory architecture and rapidly solve the wave field for a number of shots by using the lower and upper matrix factors. Using both synthetic datasets and real datasets obtained by a 3D wide azimuth survey, the long-wavelength component of the P-wave and S-wave velocity models is reconstructed and the proposed modeling and inversion algorithm are verified. A cluster of 80 CPU cores is used for this study.
From entropy-maximization to equality-maximization: Gauss, Laplace, Pareto, and Subbotin
NASA Astrophysics Data System (ADS)
Eliazar, Iddo
2014-12-01
The entropy-maximization paradigm of statistical physics is well known to generate the omnipresent Gauss law. In this paper we establish an analogous socioeconomic model which maximizes social equality, rather than physical disorder, in the context of the distributions of income and wealth in human societies. We show that-on a logarithmic scale-the Laplace law is the socioeconomic equality-maximizing counterpart of the physical entropy-maximizing Gauss law, and that this law manifests an optimized balance between two opposing forces: (i) the rich and powerful, striving to amass ever more wealth, and thus to increase social inequality; and (ii) the masses, struggling to form more egalitarian societies, and thus to increase social equality. Our results lead from log-Gauss statistics to log-Laplace statistics, yield Paretian power-law tails of income and wealth distributions, and show how the emergence of a middle-class depends on the underlying levels of socioeconomic inequality and variability. Also, in the context of asset-prices with Laplace-distributed returns, our results imply that financial markets generate an optimized balance between risk and predictability.
NASA Astrophysics Data System (ADS)
Fabijonas, Bruce R.
2002-09-01
We examine a Maple implementation of two distinct approaches to Laplace's method used to obtain asymptotic expansions of Laplace-type integrals. One algorithm uses power series reversion, whereas the other expands all quantities in Taylor or Puiseux series. These algorithms are used to derive asymptotic expansions for the real valued modified Bessel functions of pure imaginary order and real argument that mimic the well-known corresponding expansions for the unmodified Bessel functions.
NASA Technical Reports Server (NTRS)
Lyusternik, L. A.
1980-01-01
The mathematics involved in numerically solving for the plane boundary value of the Laplace equation by the grid method is developed. The approximate solution of a boundary value problem for the domain of the Laplace equation by the grid method consists of finding u at the grid corner which satisfies the equation at the internal corners (u=Du) and certain boundary value conditions at the boundary corners.
NASA Astrophysics Data System (ADS)
Santos, J. C.; Rubini, J.; Silva, L. P. C.; Caetano, R. E.
2015-09-01
The use of two electro-optical modulators linked in series, one for sensing and one for recovering signals, was formerly presented by some of the authors as a solution for interrogation of optical fiber sensor systems based on WLI method. A key feature required from such systems is that half-wave voltage (Vπ) of recovering modulator must be as small as possible. Aiming at meeting this requirement, in this paper it is presented the use of an unbalanced Michelson Interferometer implemented using an integrated optics component as recover interferometer in an optical voltage transformer intended for high voltage measurements.
Nikoo, Mohammad Reza; Kerachian, Reza; Karimi, Akbar; Azadnia, Ali Asghar
2013-03-01
In this paper, a new methodology is developed for integrated allocation of water and waste-loads in river basins utilizing a fuzzy transformation method (FTM). The fuzzy transformation method is used to incorporate the existing uncertainties in model inputs. In the proposed methodology, the FTM, as a simulation model, is utilized in an optimization framework for constructing a fuzzy water and waste-loads allocation model. In addition, economic as well as environmental impacts of water allocation to different water users are considered. For equitable water and waste load allocation, all possible coalition of water users are considered and total benefit of each coalition, which is a fuzzy number, is reallocated to water users who are participating in the coalition. The fuzzy cost savings are reallocated using a fuzzy nucleolus cooperative game and the FTM. As a case study, the Dez River system in south-west of Iran is modeled and analyzed using the methodology developed here. The results show the effectiveness of the methodology in optimal water and waste-loads allocations under uncertainty.
Liu, Qian; Sun, Pei-Yan; Gao, Zhen-Hui; Cai, Wen-Sheng; Shao, Xue-Guang
2010-03-01
In the present work, the combination of attenuated total reflectance-Fourier transform infrared spectrometry (ATR-FTIR) and pattern recognition, including principal components analysis (PCA) and hierarchical cluster analysis (HCA), is used as a fast and convenient analytical tool to classify oil samples. Twenty five samples including crude oils and fuel oils with different total contents of n-alkanes were analyzed. It was found that multiplicative scatter correction (MSC) and continuous wavelet transform (CWT) as a pretreatment method could improve the classification results of pattern recognition. The classification results were proved to be in agreement with the origin of the oil samples. The oils with high content of n-alkanes and those with low content were classified clearly by this developed method, but it still had some constraint to differentiating oils with little difference. The present work provides a feasible method for quick classification of oils, which can be used for the initial identification of spill oils and afford useful information for the further identification of the oils.
Rajiv, P; Rajeshwari, Sivaraj; Venckatesh, Rajendran
2013-12-01
Fourier transform infrared spectroscopy (FT-IR) and Gas chromatography-mass spectroscopy have been carried out to investigate the chemical composition of Parthenium mediated vermicompost. Four different concentrations of Parthenium and cow dung mixtures were vermicomposted using the earthworms (Eudrilus eugeniae). FT-IR spectra reveal the absence of Parthenin toxin (sesquiterpene lactone) and phenols in vermicompost which was obtained from high concentration of cow dung mixed treatments. GC-MS analysis shows no phenolic compounds and predominant level of intermediate metabolites such as 4,8,12,16-Tetramethylheptadecan-4-olide (7.61%), 2-Pentadecanone, 6,10,14-trimethyl- (5.29%) and Methyl 16-methyl-heptadecanoate (4.69%) during the vermicomposting process. Spectral results indicated that Parthenin toxin and phenols can be eradicated via vermicomposting if mixed with appropriate quantity of cow dung.
SnO2-MOF-Fabry-Perot humidity optical sensor system based on fast Fourier transform technique
NASA Astrophysics Data System (ADS)
Lopez-Aldaba, A.; Lopez-Torres, D.; Ascorbe, J.; Rota-Rodrigo, S.; Elosua, C.; Lopez-Amo, M.; Arregui, F. J.; Corres, J. M.; Auguste, J.-L.; Jamier, R.; Roy, P.
2016-05-01
In this paper, a new sensor system for relative humidity measurements based on a SnO2 sputtering deposition on a microstructured optical fiber (MOF) low-finesse Fabry-Perot (FP) sensing head is presented and characterized. The interrogation of the sensing head is carried out by monitoring the Fast Fourier Transform phase variations of the FP interference frequency. This method is low-sensitive to signal amplitude variations and also avoids the necessity of tracking the evolution of peaks and valleys in the spectrum. The sensor is operated within a wide humidity range (20%-90% relative humidity) with a maximum sensitivity achieved of 0.14rad/%. The measurement method uses a commercial optical interrogator as the only active element, this compact solution allows real time analysis of the data.
NASA Astrophysics Data System (ADS)
Rajiv, P.; Rajeshwari, Sivaraj; Venckatesh, Rajendran
2013-12-01
Fourier transform infrared spectroscopy (FT-IR) and Gas chromatography-mass spectroscopy have been carried out to investigate the chemical composition of Parthenium mediated vermicompost. Four different concentrations of Parthenium and cow dung mixtures were vermicomposted using the earthworms (Eudrilus eugeniae). FT-IR spectra reveal the absence of Parthenin toxin (sesquiterpene lactone) and phenols in vermicompost which was obtained from high concentration of cow dung mixed treatments. GC-MS analysis shows no phenolic compounds and predominant level of intermediate metabolites such as 4,8,12,16-Tetramethylheptadecan-4-olide (7.61%), 2-Pentadecanone, 6,10,14-trimethyl- (5.29%) and Methyl 16-methyl-heptadecanoate (4.69%) during the vermicomposting process. Spectral results indicated that Parthenin toxin and phenols can be eradicated via vermicomposting if mixed with appropriate quantity of cow dung.
Investigation of Jovian satellites and the origin of Jovian system by LAPLACE
NASA Astrophysics Data System (ADS)
Sasaki, Sho; Okada, Tatsuaki; Yamaji, Atsushi; Fujimoto, Masaki; Kasaba, Yasumasa; Kimura, Jun; Ikoma, Masahiro; Hussmann, Hauke; Kuramoto, Kiyoshi
LAPLACE (ESA-JAXA joint mission for the Jovian system) was selected as one of future ESA scientific missions Cosmic Vision in October 2007. LAPLACE is a mission with three spacecrafts aiming at coordinated observations of Jovian satellites and the magnetosphere, atmosphere and interior of Jupiter. An orbiter around Europa or Ganymede is involved. There is a possibility that JAXA (Japan Aerospace Exploration Agency) will take a role on the magnetosphere spinner. Japanese scientists working on the origin and evolution of Jupiter, satellite evolution, and astrobiology have been participating in the LAPLACE working group in Japan. Detailed observation of Jovian satellites Europa, Ganymede, Callisto and Io as well as smaller satellites such as Amalthea would be important also for the study of the origin of Jovian system. Resurfacing processes on Europa and Ganymede should be studied to know the properties of the internal oceans. The processes can be investigated by infrared observation for salt minerals and amorphous/crystal ices. Not only the thickness of icy crust of Europa but also thickness of the ocean and its bottom topography should be important targets, which would be investigated by gravity and magnetism measurements. For both Europa and Ganymede, the surface layering and structure of icy crust should be an interesting geological target, which will be clarified by subsurface radar. In Japan, KAGUYA is observing the Moon, and Venus remote sensing mission (PLANET-C) and Mercury mission Bepi Colombo will be launched in 2011 and 2013, respectively. Several instruments such as cameras, spectrometers, a laser altimeter, a radar, a magnetometer, plasma instruments, and a dust detector should come from the heritage of instruments on board KAGUYA, PLANET-C, and BepiColombo.
The application of the Galerkin method to solving PIES for Laplace's equation
NASA Astrophysics Data System (ADS)
Bołtuć, Agnieszka; Zieniuk, Eugeniusz
2016-06-01
The paper presents the application of the Galerkin method to solving the parametric integral equation system (PIES) on the example of Laplace's equation. The main aim of the paper is the analysis of the effectiveness of two methods for PIES solving: the collocation method and the Galerkin method. Researches were performed on two examples with analytical solutions. Tests concern mainly the accuracy of obtained numerical solutions and their stability. For both analyzed methods calculations were made with the various number of expressions in the approximation series, whilst in the collocation method two variants of the arrangement of collocation points were considered. We also compared the complexity of both methods using the execution time.
NASA Astrophysics Data System (ADS)
Kwon, Kibum
A dynamic analysis of the interaction between a crack and an auxetic (negative Poisson ratio)/non-auxetic inclusion is presented. The two most important fracture parameters, namely the stress intensity factors and the T-stress are analyzed by using the symmetric Galerkin boundary element method in the Laplace domain for three different models of crack-inclusion interaction. To investigate the effects of auxetic inclusions on the fracture behavior of composites reinforced by this new type of material, comparisons of the dynamic stress intensity factors and the dynamic T-stress are made between the use of auxetic inclusions as opposed to the use of traditional inclusions. Furthermore, the technique presented in this research can be employed to analyze for the interaction between a crack and a cluster of auxetic/non-auxetic inclusions. Results from the latter models can be employed in crack growth analysis in auxetic-fiber-reinforced composites.
Li, Fuzhong
2014-03-01
Tai Ji Quan, developed as a martial art, has traditionally served multiple purposes, including self-defense, competition/performance, and health promotion. With respect to health, the benefits historically and anecdotally associated with Tai Ji Quan are now being supported by scientific and clinical research, with mounting evidence indicating its potential value in preventing and managing various diseases and improving well-being and quality of life in middle-aged and older adults. The research findings produced to date have both public health significance and clinical relevance. However, because of its roots in the martial arts, transforming traditional Tai Ji Quan movements and training approaches into contemporary therapeutic programs and functional applications is needed to maximize its ultimate utility. This paper addresses this issue by introducing Tai Ji Quan: Moving for Better Balance, a functional therapy that involves the use of Tai Ji Quan principles and Yang-style-based movements to form an innovative, contemporary therapeutic approach that integrates motor, sensory, and cognitive components to improve postural control, gait, and mobility for older adults and those who have neurodegenerative movement impairments. It provides a synergy of traditional and contemporary Tai Ji Quan practice with the ultimate goal of improving balance and gait, enhancing performance of daily functional tasks, and reducing incidence of falls among older adults.
Mosca, Silvia; Benedetti, Paolo; Guerriero, Ettore; Rotatori, Mauro
2014-11-01
Nitrous oxide (N2O) is the third most important greenhouse gas after carbon dioxide and methane, and contributes about 6% to the greenhouse effect. Nitrous oxide is a minor component of the atmosphere, and it is a thousand times less than carbon dioxide (CO2). Nevertheless, it is much more potent than CO2 and methane, owing to its long stay in the atmosphere of approximately 120 yr and the high global warmingpotential (GWP) of298 times that of CO2. Although greenhouse gases are natural in the atmosphere, human activities have changed the atmospheric concentrations. Most of the values of emission of nitrous oxide are still obtained by means ofemission factors and not actually measured; the lack ofreal data may result in an underestimation ofcurrent emissions. The emission factors used for the calculation of N2O can be obtained from the "Guidelines for the implementation of the national inventory of emissions" of the Intergovernmental Panel on Climate Change, which refer to all nations for the realization of their inventory. This study will present real data, measured in several Italian cement plants with different characteristics. The work also shows a comparison between N2O concentration measured with in situ-Fourier transform IR (FTIR) and the reference method EN ISO 21258 based on nondispersive IR (NDIR), in order to investigate the interfering compounds in the measurement with NDIR.
Li, Fuzhong
2014-01-01
Tai Ji Quan, developed as a martial art, has traditionally served multiple purposes, including self-defense, competition/performance, and health promotion. With respect to health, the benefits historically and anecdotally associated with Tai Ji Quan are now being supported by scientific and clinical research, with mounting evidence indicating its potential value in preventing and managing various diseases and improving well-being and quality of life in middle-aged and older adults. The research findings produced to date have both public health significance and clinical relevance. However, because of its roots in the martial arts, transforming traditional Tai Ji Quan movements and training approaches into contemporary therapeutic programs and functional applications is needed to maximize its ultimate utility. This paper addresses this issue by introducing Tai Ji Quan: Moving for Better Balance, a functional therapy that involves the use of Tai Ji Quan principles and Yang-style-based movements to form an innovative, contemporary therapeutic approach that integrates motor, sensory, and cognitive components to improve postural control, gait, and mobility for older adults and those who have neurodegenerative movement impairments. It provides a synergy of traditional and contemporary Tai Ji Quan practice with the ultimate goal of improving balance and gait, enhancing performance of daily functional tasks, and reducing incidence of falls among older adults. PMID:25126445
NASA Astrophysics Data System (ADS)
Yang, Bian-Xia; Sun, Hong-Rui; Feng, Zhaosheng
In this paper, we are concerned with the unilateral global bifurcation structure of fractional differential equation (‑Δ)αu(x) = λa(x)u(x) + F(x,u,λ),x ∈ Ω,u = 0,inℝN\\Ω with nondifferentiable nonlinearity F. It shows that there are two distinct unbounded subcontinua 𝒞+ and 𝒞‑ consisting of the continuum 𝒞 emanating from [λ1 ‑ d,λ1 + d] ×{0}, and two unbounded subcontinua 𝒟+ and 𝒟‑ consisting of the continuum 𝒟 emanating from [λ1 ‑d¯,λ1 + d¯] ×{∞}. As an application of this unilateral global bifurcation results, we present the existence of the principal half-eigenvalues of the half-linear fractional eigenvalue problem. Finally, we deal with the existence of constant sign solutions for a class of fractional nonlinear problems. Main results of this paper generalize the known results on classical Laplace operators to fractional Laplace operators.
Energy state distributions at oxide-semiconductor interfaces investigated by Laplace DLTS
NASA Astrophysics Data System (ADS)
Dobaczewski, L.; Markevich, V. P.; Kruszewski, P.; Hawkins, I. D.; Peaker, A. R.
2009-12-01
At disordered Si/SiO2 interfaces the lattice mismatching results in dangling bond Pb centres forming a rather broad distribution of energy states. In this study these energy distributions have been determined using isothermal current Laplace deep level transient spectroscopy (DLTS) for the (1 0 0) and (1 1 1) interface orientations. The (1 1 1) distribution is 0.08 eV broad and centred at 0.38 eV below the silicon conduction band. This is consistent with only Pb0 states being present. While for the (1 0 0) orientation this distribution is broader (0.1 eV) and deeper (0.43 eV) on the energy scale. Detailed studies revealed two types of the interface states in this broad distribution: one similar to the (1 1 1) orientation while the other has a negative-U character in which the emission rate versus surface potential dependence is qualitatively different from that observed for Pb0 and is presumed to be Pb1. Discrepancies between Pb states energy distributions obtained with a use of the isothermal Laplace and conventional DLTS measurements are discussed. The presented experimental procedure can be used for analysis of interface states observed at interfaces of other semiconductor-oxide/dielectric systems.
1987-01-01
Microspectrophotometric measurements were performed on 217 photoreceptors from cynomolgus, Macaca fascicularis, and rhesus, M. mulatta, monkeys. The distributions of cell types, for rods and blue, green, and red cones were: 52, 12, 47, and 44, respectively, for the cynomolgus, and 22, 4, 13, and 13 for the rhesus. Visual cells were obtained fresh (unfixed), mounted in various media (some containing 11- cis-retinal), and then located visually under dim red (650 nm) illumination. Absolute absorbance (A), linear dichroism (LD), and bleaching difference (BD) absorbance spectra were recorded through the sides of outer segments. The spectra were subjected to rigorous selection criteria, followed by digital averaging and Fourier transform filtering. Statistical methods were also applied to the accepted samples in the estimation of population means and variances. The wavelength of mean peak absorbance (lambda max) and the standard error at 95% certainty of the rod and blue, green, and red cone pigments in cynomolgus were 499.7 +/- 2.5, 431.4 +/- 4.2, 533.9 +/- 2.4, and 565.9 +/- 2.8 nm, respectively. The rhesus pigments were statistically indistinguishable from the cynomolgus, having lambda max of approximately 500, 431, 534, and 566 nm. Statistical tests did not reveal the presence of a lambda max subpopulation (i.e., anomalous pigments). The bandwidth of each alpha-band was determined in two segments, giving rise to the longwave half-density (LWHDBW), shortwave half-density (SWHDBW), and total half-density (THDBW) bandwidths. The LWHDBW was found to have the smallest variance. Both the LWHDBW and the THDBW showed linear dependence on the peak wavenumber (lambda max)-1 for the four macaque pigments. PMID:3598558
Snyder, R.W.
1982-01-01
The development of application programs for infrared spectroscopy has been an ongoing proposition for a number of years. This development, however, was accelerated with the advent of Fourier transform infared (FT-IR) instruments and their built-in mini-computers. The uses and pitfalls of several of these routines are discussed in this thesis. A least-squares curve resolving program has been developed and the use of this program is also discussed. The analysis of complex, multicomponent polymeric materials, such as coal and oil shale, by conventional infrared spectroscopy has been a difficult problem. The use of FT-IR spectroscopy for the qualitative and quantitative analysis of these types of materials is discussed. A characterization of oil shale from the Mahogany Zone of the Green River Formation has been obtained by FT-IR. A quantitative analysis of the mineral component by FT-IR spectroscopy is shown to be comparable to that obtained by x-ray diffraction when considering broad mineral types, i.e., carbonates. Methods for the FT-IR analysis of the organic component, both from the whole shale and from kerogen specimens, have been refined. There is a good correlation between the intensity of alkyl bands and Fisher assay yields. An assessment is made of the applicability of extinction coefficients obtained from paraffins to their use in quantitative analysis in oil shales. A quantitative analysis of OH content in coal by FT-IR is comparable to that done by other methods (i.e., chemical and NMR). An analysis is also made of the various types of OH groups in coal.
The Classical Laplace Plane and Its use as a Stable Disposal Orbit for GEO
NASA Astrophysics Data System (ADS)
Rosengren, A.; Scheeres, D.; McMahon, J.
2013-09-01
The geosynchronous Earth orbit (GEO) is the most susceptible region to space debris because there is no natural cleansing mechanism, such as atmospheric drag. Placing satellites in super-synchronous disposal orbits at the ends of their operational lifetimes has been recommended and practiced as one possible means of protecting this environment. The discovery of the high area-to-mass ratio (HAMR) debris population in near geosynchronous orbit (ca. 2004) raises concern for the long-term sustainability of this unique resource. It is currently believed that HAMR objects are sheets of multilayer insulation detaching from satellites in GEO disposal orbits due to surface degradation and material deterioration. The low energy release of HAMR objects from aging satellites abandoned in disposal orbits is not directly addressed in the national policies that established the graveyard. The current disposal regions cannot account for the large solar radiation pressure (SRP) perturbations of HAMR objects, implying that these storage orbits are not well suited as a graveyard. The orbital dynamics of uncontrolled GEO satellites is governed by the oblateness of the Earth and luni-solar gravitational interactions. By itself, Earth's oblateness causes the pole of the orbital plane to precess around Earth's rotation pole. Lunisolar perturbations will have a similar effect, but the precession will now take place about the orbit poles of the Moon and the Sun, respectively. The classical Laplace plane is the mean reference plane about whose axis the satellite's orbit precesses. On the Laplace place, the secular orbital evolution driven by the combined effects of these perturbations is zero, so that the orbits are frozen. The Laplace plane at GEO lies between the plane of the Earth's equator and that of the ecliptic, passing through their intersection, and has an inclination of about 7.5 degrees relative to Earth's equator. The uncontrolled GEO satellites precess at a constant inclination
Massopust, P.R.
1997-08-01
All solutions of an in its angular coordinates continuously perturbed Laplace-Beltrami equation in the open unit ball IB{sup n+2} {contained_in} IR{sup n+2}, n {ge} 1, are characterized. Moreover, it is shown that such pertubations yield distributional boundary values which are different from, but algebraically and topologically equivalent to, the hyperfunctions of Lions & Magenes. This is different from the case of radially perturbed Laplace-Beltrami operators (cf. [7]) where one has stability of distributional boundary values under such perturbations.
Doroodmand, Mohammad Mahdi
2013-05-01
Effect of "Discrete Fourier Transform" (DFT) is studied for electrochemical detection of some electroactive species using multi-walled carbon nanotube/polyacrylonitrile ceramic fiber as ultra micro electrode. Based on DFT theory, two independent phases i.e. the imaginary and real phases are evaluated during the oxidation/reduction of the quasi-reversible or irreversible electroactive species, revealing the independent components of imaginary (IImaginary) and real (IReal) currents. The results show that, in different electrochemical modes such as cyclic voltammetry (CV), the contribution of DFT to the electrochemical signals significantly improves the detection limit of the electrochemical technique. More sensitive signals are obtained at high scan rates according to the combination of electrochemical techniques with the DFT theory. The reliability of DFT algorithm was evaluated for rapid determination of trace amount of hydrazine (N2H4) at a scan rate up to 800 V s(-1). In this study, the amounts of phase and amplitude were estimated to 1.69 and 31.57, respectively. The detection limit of hydrazine was 4.13×10(-9) M. The application of this technique was also evaluated for determination of hydrazine in different industrial wastewater samples.
Letzel, Thomas; Bayer, Anne; Schulz, Wolfgang; Heermann, Alexandra; Lucke, Thomas; Greco, Giorgia; Grosse, Sylvia; Schüssler, Walter; Sengl, Manfred; Letzel, Marion
2015-10-01
A large number of anthropogenic trace contaminants such as pharmaceuticals, their human metabolites and further transformation products (TPs) enter wastewater treatment plants on a daily basis. A mixture of known, expected, and unknown molecules are discharged into the receiving aquatic environment because only partial elimination occurs for many of these chemicals during physical, biological and chemical treatment processes. In this study, an array of LC-MS methods from three collaborating laboratories was applied to detect and identify anthropogenic trace contaminants and their TPs in different waters. Starting with theoretical predictions of TPs, an efficient workflow using the combination of target, suspected-target and non-target strategies for the identification of these TPs in the environment was developed. These techniques and strategies were applied to study anti-hypertensive drugs from the sartan group (i.e., candesartan, eprosartan, irbesartan, olmesartan, and valsartan). Degradation experiments were performed in lab-scale wastewater treatment plants, and a screening workflow including an inter-laboratory approach was used for the identification of transformation products in the effluent samples. Subsequently, newly identified compounds were successfully analyzed in effluents of real wastewater treatment plants and river waters.
Identifying the most likely contributors to a Y-STR mixture using the discrete Laplace method.
Andersen, Mikkel Meyer; Eriksen, Poul Svante; Mogensen, Helle Smidt; Morling, Niels
2015-03-01
In some crime cases, the male part of the DNA in a stain can only be analysed using Y chromosomal markers, e.g. Y-STRs. This may be the case in e.g. rape cases, where the male components can only be detected as Y-STR profiles, because the fraction of male DNA is much smaller than that of female DNA, which can mask the male results when autosomal STRs are investigated. Sometimes, mixtures of Y-STRs are observed, e.g. in rape cases with multiple offenders. In such cases, Y-STR mixture analysis is required, e.g. by mixture deconvolution, to deduce the most likely DNA profiles from the contributors. We demonstrate how the discrete Laplace method can be used to separate a two person Y-STR mixture, where the Y-STR profiles of the true contributors are not present in the reference dataset, which is often the case for Y-STR profiles in real case work. We also briefly discuss how to calculate the weight of the evidence using the likelihood ratio principle when a suspect's Y-STR profile fits into a two person mixture. We used three datasets with between 7 and 21 Y-STR loci: Denmark (n=181), Somalia (n=201) and Germany (n=3443). The Danish dataset with 21 loci was truncated to 15 and 10 loci to examine the effect of the number of loci. For each of these datasets, an out of sample simulation study was performed: A total of 550 mixtures were composed by randomly sampling two haplotypes, h1 and h2, from the dataset. We then used the discrete Laplace method on the remaining data (excluding h1 and h2) to rank the contributor pairs by the product of the contributors' estimated haplotype frequencies. Successful separation of mixtures (defined by the observation that the true contributor pair was among the 10 most likely contributor pairs) was found in 42-52% of the cases for 21 loci, 69-75% for 15 loci and 92-99% for 10 loci or less depending on the dataset and how the discrete Laplace model was chosen. Y-STR mixtures with many loci are difficult to separate, but even haplotypes
LAPLACE: A mission to Europa and the Jupiter System for ESA's Cosmic Vision Programme
NASA Astrophysics Data System (ADS)
Blanc, Michel; Alibert, Yann; André, Nicolas; Atreya, Sushil; Beebe, Reta; Benz, Willy; Bolton, Scott J.; Coradini, Angioletta; Coustenis, Athena; Dehant, Véronique; Dougherty, Michele; Drossart, Pierre; Fujimoto, Masaki; Grasset, Olivier; Gurvits, Leonid; Hartogh, Paul; Hussmann, Hauke; Kasaba, Yasumasa; Kivelson, Margaret; Khurana, Krishan; Krupp, Norbert; Louarn, Philippe; Lunine, Jonathan; McGrath, Melissa; Mimoun, David; Mousis, Olivier; Oberst, Juergen; Okada, Tatsuaki; Pappalardo, Robert; Prieto-Ballesteros, Olga; Prieur, Daniel; Regnier, Pascal; Roos-Serote, Maarten; Sasaki, Sho; Schubert, Gerald; Sotin, Christophe; Spilker, Tom; Takahashi, Yukihiro; Takashima, Takeshi; Tosi, Federico; Turrini, Diego; van Hoolst, Tim; Zelenyi, Lev
2009-03-01
The exploration of the Jovian System and its fascinating satellite Europa is one of the priorities presented in ESA’s “Cosmic Vision” strategic document. The Jovian System indeed displays many facets. It is a small planetary system in its own right, built-up out of the mixture of gas and icy material that was present in the external region of the solar nebula. Through a complex history of accretion, internal differentiation and dynamic interaction, a very unique satellite system formed, in which three of the four Galilean satellites are locked in the so-called Laplace resonance. The energy and angular momentum they exchange among themselves and with Jupiter contribute to various degrees to the internal heating sources of the satellites. Unique among these satellites, Europa is believed to shelter an ocean between its geodynamically active icy crust and its silicate mantle, one where the main conditions for habitability may be fulfilled. For this very reason, Europa is one of the best candidates for the search for life in our Solar System. So, is Europa really habitable, representing a “habitable zone” in the Jupiter system? To answer this specific question, we need a dedicated mission to Europa. But to understand in a more generic way the habitability conditions around giant planets, we need to go beyond Europa itself and address two more general questions at the scale of the Jupiter system: to what extent is its possible habitability related to the initial conditions and formation scenario of the Jovian satellites? To what extent is it due to the way the Jupiter system works? ESA’s Cosmic Vision programme offers an ideal and timely framework to address these three key questions. Building on the in-depth reconnaissance of the Jupiter System by Galileo (and the Voyager, Ulysses, Cassini and New Horizons fly-by’s) and on the anticipated accomplishments of NASA’s JUNO mission, it is now time to design and fly a new mission which will focus on these
NASA Astrophysics Data System (ADS)
Kholshevnikov, Konstantin V.; Shaidulin, Vakhit Sh.
2016-11-01
The main form of the representation of a gravitational potential V for a celestial body T in outer space is the Laplace series in solid spherical harmonics (R/r)^{n+1}Y_n(θ ,λ ) with R being the radius of the enveloping T sphere. The surface harmonic Y_n satisfies the inequality < Y_nrangle < Cn^{-σ }. The angular brackets mark the maximum of a function's modulus over a unit sphere. For bodies with an irregular structure σ = 5/2 , and this value cannot be increased generally. However, a class of irregular bodies (smooth bodies with peaked mountains) has been found recently in which σ = 3 . In this paper, we will prove the exactness of this estimate, showing that a body belonging to the above class does exist and 0<\\varlimsup n^3< Y_nrangle <∞ for it.
Lu, Dingjie; Xie, Yi Min; Huang, Xiaodong; Zhou, Shiwei; Li, Qing
2015-11-28
Analytical studies on the size effects of a simply-shaped beam fixed at both ends have successfully explained the sudden changes of effective Young's modulus as its diameter decreases below 100 nm. Yet they are invalid for complex nanostructures ubiquitously existing in nature. In accordance with a generalized Young-Laplace equation, one of the representative size effects is transferred to non-uniformly distributed pressure against an external surface due to the imbalance of inward and outward loads. Because the magnitude of pressure depends on the principal curvatures, iterative steps have to be adopted to gradually stabilize the structure in finite element analysis. Computational results are in good agreement with both experiment data and theoretical prediction. Furthermore, the investigation on strengthened and softened Young's modulus for two complex nanostructures demonstrates that the proposed computational method provides a general and effective approach to analyze the size effects for nanostructures in arbitrary shape.
Infinite-Dimensional Schur-Weyl Duality and the Coxeter-Laplace Operator
NASA Astrophysics Data System (ADS)
Tsilevich, N. V.; Vershik, A. M.
2014-05-01
We extend the classical Schur-Weyl duality between representations of the groups and to the case of and the infinite symmetric group . Our construction is based on a "dynamic," or inductive, scheme of Schur-Weyl dualities. It leads to a new class of representations of the infinite symmetric group, which has not appeared earlier. We describe these representations and, in particular, find their spectral types with respect to the Gelfand-Tsetlin algebra. The main example of such a representation acts in an incomplete infinite tensor product. As an important application, we consider the weak limit of the so-called Coxeter-Laplace operator, which is essentially the Hamiltonian of the XXX Heisenberg model, in these representations.
NASA Astrophysics Data System (ADS)
Wang, Rong Feng; Mei, Zhong Lei; Yang, Xin Yu; Ma, Xiang; Cui, Tie Jun
2014-04-01
For ideal invisibility cloaks, electromagnetic radiations cannot penetrate through the cloaking shell. However, researchers have suggested that the originally hidden object with a cloaking shell is visible to the outside world when it is covered by an "anticloak." In this paper, we give the first experimental verification of the "anticloak" for the Laplace equation, which requires negative conductivity profiles. The proposed device consists of two layers—the cloak and anticloak, which can work individually or collectively and give rise to different functions. Functionality switching among the invisibility cloak, anticloak, transparent cloak, superscatterer, and illusion is suggested and demonstrated. Based on the circuit theory, we fabricate a switching resistor network with both positive and negative resistors to emulate the cloaking and anticloaking interactions. The switchable cloaking, anticloaking, transparent, superscatterer, and illusion performances are confirmed by the experiments and/or numerical simulations.
Origin and Use of the Laplace Distribution in Daily Sunspot Numbers
NASA Astrophysics Data System (ADS)
Noble, P. L.; Wheatland, M. S.
2013-02-01
Recently Pop ( Solar Phys. 276, 351, 2012) identified a Laplace (or double exponential) distribution in the number of days with a given absolute value in the change over a day, in sunspot number, for days on which the sunspot number does change. We show this phenomenological rule has a physical origin attributable to sunspot formation, evolution, and decay, rather than being due to the changes in sunspot number caused by groups rotating onto and off the visible disc. We also demonstrate a simple method to simulate daily sunspot numbers over a solar cycle using the Pop ( Solar Phys. 276, 351, 2012) result, together with a model for the cycle variation in the mean sunspot number. The procedure is applied to three recent solar cycles. We check that the simulated sunspot numbers reproduce the observed distribution of daily changes over those cycles.
Bayesian inference using two-stage Laplace approximation for differential equation models
NASA Astrophysics Data System (ADS)
Dass, Sarat C.; Lee, Jaeyong; Lee, Kyoungjae
2016-11-01
We consider the problem of Bayesian inference for parameters in non-linear regression models whereby the underlying unknown response functions are formed by a set of differential equations. Bayesian methods of inference for unknown parameters rely primarily on the posterior obtained by Bayes rule. For differential equation models, analytic and closed forms for the posterior are not available and one has to resort to approximations. We propose a two-stage Laplace expansion to approximate the marginal likelihood, and hence, the posterior, to obtain an approximate closed form solution. For large sample sizes, the method of inference borrows from non-linear regression theory for maximum likelihood estimates, and is therefore, consistent. Our approach is exact in the limit and does not need the specification of an additional penalty parameter. Examples in this paper include the exponential model and SIR (Susceptible-Infected-Recovered) disease spread model.
Green's function and image system for the Laplace operator in the prolate spheroidal geometry
NASA Astrophysics Data System (ADS)
Xue, Changfeng; Deng, Shaozhong
2017-01-01
In the present paper, electrostatic image theory is studied for Green's function for the Laplace operator in the case where the fundamental domain is either the exterior or the interior of a prolate spheroid. In either case, an image system is developed to consist of a point image inside the complement of the fundamental domain and an additional symmetric continuous surface image over a confocal prolate spheroid outside the fundamental domain, although the process of calculating such an image system is easier for the exterior than for the interior Green's function. The total charge of the surface image is zero and its centroid is at the origin of the prolate spheroid. In addition, if the source is on the focal axis outside the prolate spheroid, then the image system of the exterior Green's function consists of a point image on the focal axis and a line image on the line segment between the two focal points.
Laplace-Runge-Lenz vector in quantum mechanics in noncommutative space
Gáliková, Veronika; Kováčik, Samuel; Prešnajder, Peter
2013-12-15
The main point of this paper is to examine a “hidden” dynamical symmetry connected with the conservation of Laplace-Runge-Lenz vector (LRL) in the hydrogen atom problem solved by means of non-commutative quantum mechanics (NCQM). The basic features of NCQM will be introduced to the reader, the key one being the fact that the notion of a point, or a zero distance in the considered configuration space, is abandoned and replaced with a “fuzzy” structure in such a way that the rotational invariance is preserved. The main facts about the conservation of LRL vector in both classical and quantum theory will be reviewed. Finally, we will search for an analogy in the NCQM, provide our results and their comparison with the QM predictions. The key notions we are going to deal with are non-commutative space, Coulomb-Kepler problem, and symmetry.
Numerical determination of the fundamental eigenvalue for the Laplace operator on a spherical domain
NASA Technical Reports Server (NTRS)
Walden, H.
1977-01-01
Methods for obtaining approximate solutions for the fundamental eigenvalue of the Laplace-Beltrami operator (i.e., the membrane eignevalue problem for the vibration equation) on the unit spherical surface are developed. Two types of spherical surface domains are considered: the interior of a spherical triangle, and the exterior of a great circle arc extending for less than pi radians (a spherical surface with a slit). In both cases, zero boundary conditions are imposed. In order to solve the resulting second-order elliptic partial differential equations in two independent variables, a finite difference approximation is employed. The fundamental eigenvalue is approximated by iteration utilizing the power method and point successive overrelaxation. Some numerical results are given and compared, in certain special cases, with analytical solutions to the eigenvalue problem. The significance of the numerical eigenvalue results is discussed in terms of the singularities in the solution of three-dimensional boundary-value problems near a polyhedral corner of the domain.
Transformational Learners: Transformational Teachers
ERIC Educational Resources Information Center
Jones, Marguerite
2009-01-01
Transformational learning, according to Mezirow (1981), involves transforming taken-for-granted frames of reference into more discriminating, flexible "habits of mind". In teacher education, transformative learning impacts on the development of students' action theories, self-efficacy and professional attributes. Although considered…
NASA Astrophysics Data System (ADS)
Telyakovskii, D. S.
2017-01-01
In this paper we weaken the sufficient conditions of harmonicity for functions of two variables. I.I. Privalov had shown that a continuous function that satisfies the Laplace equation in each point of the domain is harmonic. For function of two variables the Privalov’s condition on continuity can be weakened. G.P. Tolstov replaced the continuity condition by the boundness condition, later the author had shown that summability is sufficient. At the same time summability condition can not be weakened substantially. In this paper, while we keep the summability condition, we provide the sufficient condition for harmonicity of the functions, that satisfy less restricted condition than the Laplace equation in all points of the domain. We assume that arbitrary close to any point ζ there exists a collection of four nodes for which a difference relation of Schwartz type for the Laplace equation can be made arbitrary small by the absolute value. Nodes are the ends of two mutually perpendicular segments, that intersect at point ζ. We need to impose a certain weakened continuous assumption on function itself, in case of function that satisfy the traditional Laplace condition this continuity condition follows from the existence of the partial derivatives.
Benhammouda, Brahim
2015-01-01
The solution of higher-index Hessenberg differential-algebraic equations (DAEs) is of great importance since this type of DAEs often arises in applications. Higher-index DAEs are known to be numerically and analytically difficult to solve. In this paper, we present a new analytical method for the solution of two classes of higher-index Hessenberg DAEs. The method is based on Adomian polynomials and the differential transform method (DTM). First, the DTM is applied to the DAE where the differential transforms of nonlinear terms are calculated using Adomian polynomials. Then, based on the index condition, the resulting recursion system is transformed into a nonsingular linear algebraic system. This system is then solved to obtain the coefficients of the power series solution. The main advantage of the proposed technique is that it does not require an index reduction nor a linearization. Two test problems are solved to demonstrate the effectiveness of the method. In addition, to extend the domain of convergence of the approximate series solution, we propose a post-treatment with Laplace-Padé resummation method.
Validity of the "Laplace Swindle" in Calculation of Giant-Planet Gravity Fields
NASA Astrophysics Data System (ADS)
Hubbard, William B.
2014-11-01
Jupiter and Saturn have large rotation-induced distortions, providing an opportunity to constrain interior structure via precise measurement of external gravity. Anticipated high-precision gravity measurements close to the surfaces of Jupiter (Juno spacecraft) and Saturn (Cassini spacecraft), possibly detecting zonal harmonics to J10 and beyond, will place unprecedented requirements on gravitational modeling via the theory of figures (TOF). It is not widely appreciated that the traditional TOF employs a formally nonconvergent expansion attributed to Laplace. This suspect expansion is intimately related to the standard zonal harmonic (J-coefficient) expansion of the external gravity potential. It can be shown (Hubbard, Schubert, Kong, and Zhang: Icarus, in press) that both Jupiter and Saturn are in the domain where Laplace's "swindle" works exactly, or at least as well as necessary. More highly-distorted objects such as rapidly spinning asteroids may not be in this domain, however. I present a numerical test for the validity and precision of TOF via polar "audit points". I extend the audit-point test to objects rotating differentially on cylinders, obtaining zonal harmonics to J20 and beyond. Models with only low-order differential rotation do not exhibit dramatic effects in the shape of the zonal harmonic spectrum. However, a model with Jupiter-like zonal winds exhibits a break in the zonal harmonic spectrum above about J10, and generally follows the more shallow Kaula power rule at higher orders. This confirms an earlier result obtained by a different method (Hubbard: Icarus 137, 357-359, 1999).
NASA Astrophysics Data System (ADS)
Chandrasekaran, A.; Ravisankar, R.; Rajalakshmi, A.; Eswaran, P.; Vijayagopal, P.; Venkatraman, B.
2015-02-01
Gamma Ray and Fourier Transform Infrared (FTIR) spectroscopic techniques were used to evaluate the natural radioactivity due to natural radionuclides and mineralogical characterization in soils of Yelagiri hills, Tamilnadu, India. Various radiological parameters were calculated to assess the radiation hazards associated with the soil. The distribution pattern of activity due to natural radionuclides is explained by Kriging method of mapping. Using FTIR spectroscopic technique the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, montmorillonite, illite, and organic carbon were identified and characterized. The extinction coefficient values were calculated to know the relative distribution of major minerals such as quartz, microcline feldspar, orthoclase feldspar and kaolinite. The calculated values indicate that the amount of quartz is higher than orthoclase feldspar, microcline feldspar and much higher than kaolinite. Crystallinity index was calculated to know the crystalline nature of quartz. The result indicates that the presence of disordered crystalline quartz in soils. The relation between minerals and radioactivity was assessed by multivariate statistical analysis (Pearson's correlation and cluster analysis). The statistical analysis confirms that the clay mineral kaolinite and non-clay mineral quartz is the major factor than other major minerals to induce the important radioactivity variables and concentrations of uranium and thorium.
Sohrabi, Mahmoud Reza; Tayefeh Zarkesh, Mahshid
2014-05-01
In the present paper, two spectrophotometric methods based on signal processing are proposed for the simultaneous determination of two components of an anti-HIV drug called lamivudine (LMV) and zidovudine (ZDV). The proposed methods are applied to synthetic binary mixtures and commercial pharmaceutical tablets without the need for any chemical separation procedures. The developed methods are based on the application of Continuous Wavelet Transform (CWT) and Derivative Spectrophotometry (DS) combined with the zero cross point technique. The Daubechies (db5) wavelet family (242 nm) and Dmey wavelet family (236 nm) were found to give the best results under optimum conditions for simultaneous analysis of lamivudine and zidovudine, respectively. In addition, the first derivative absorption spectra were selected for the determination of lamivudine and zidovudine at 266 nm and 248 nm, respectively. Assaying various synthetic mixtures of the components validated the presented methods. Mean recovery values were found to be between 100.31% and 100.2% for CWT and 99.42% and 97.37% for DS, respectively for determination of LMV and ZDV. The results obtained from analyzing the real samples by the proposed methods were compared to the HPLC reference method. One-way ANOVA test at 95% confidence level was applied to the results. The statistical data from comparing the proposed methods with the reference method showed no significant differences.
Sayet, G; Sinegre, M; Ben Reguiga, M
2014-01-01
Antibiotic Lock technique maintains catheters' sterility in high-risk patients with long-term parenteral nutrition. In our institution, vancomycin, teicoplanin, amikacin and gentamicin locks are prepared in the pharmaceutical department. In order to insure patient safety and to comply to regulatory requirements, antibiotic locks are submitted to qualitative and quantitative assays prior to their release. The aim of this study was to develop an alternative quantitation technique for each of these 4 antibiotics, using a Fourier transform infrared (FTIR) coupled to UV-Visible spectroscopy and to compare results to HPLC or Immunochemistry assays. Prevalidation studies permitted to assess spectroscopic conditions used for antibiotic locks quantitation: FTIR/UV combinations were used for amikacin (1091-1115cm(-1) and 208-224nm), vancomycin (1222-1240cm(-1) and 276-280nm), and teicoplanin (1226-1230cm(-1) and 278-282nm). Gentamicin was quantified with FTIR only (1045-1169cm(-1) and 2715-2850cm(-1)) due to interferences in UV domain of parabens, preservatives present in the commercial brand used to prepare locks. For all AL, the method was linear (R(2)=0.996 to 0.999), accurate, repeatable (intraday RSD%: from 2.9 to 7.1% and inter-days RSD%: 2.9 to 5.1%) and precise. Compared to the reference methods, the FTIR/UV method appeared tightly correlated (Pearson factor: 97.4 to 99.9%) and did not show significant difference in recovery determinations. We developed a new simple reliable analysis technique for antibiotics quantitation in locks using an original association of FTIR and UV analysis, allowing a short time analysis to identify and quantify the studied antibiotics.
Fu, C.Y.; Petrich, L.I.
1997-03-25
An image is compressed by identifying edge pixels of the image; creating a filled edge array of pixels each of the pixels in the filled edge array which corresponds to an edge pixel having a value equal to the value of a pixel of the image array selected in response to the edge pixel, and each of the pixels in the filled edge array which does not correspond to an edge pixel having a value which is a weighted average of the values of surrounding pixels in the filled edge array which do correspond to edge pixels; and subtracting the filled edge array from the image array to create a difference array. The edge file and the difference array are then separately compressed and transmitted or stored. The original image is later reconstructed by creating a preliminary array in response to the received edge file, and adding the preliminary array to the received difference array. Filling is accomplished by solving Laplace`s equation using a multi-grid technique. Contour and difference file coding techniques also are described. The techniques can be used in a method for processing a plurality of images by selecting a respective compression approach for each image, compressing each of the images according to the compression approach selected, and transmitting each of the images as compressed, in correspondence with an indication of the approach selected for the image. 16 figs.
2007-01-01
International Journal of Computational Methods , vol...Mathematical Sciences, U.S. Military Academy, West Point, NY 10996 A reprint from the International Journal of Computational Methods , vol. 3, no. 1, pp. 57...September 11, 2006 18:8 WSPC/IJCM-j050 00084 International Journal of Computational Methods Vol. 3, No. 1 (2006) 57–69 c© World Scientific Publishing
Kim, In-Hye; Son, Jun Sik; Min, Bong Ki; Kim, Young Kyoung; Kim, Kyo-Han; Kwon, Tae-Yub
2016-03-30
Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers' microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (P<0.001). Method 1 was the most sensitive to these changes, followed by surface hardness change measurements and Method 2. This study suggests that ATR-FTIR spectroscopy is potentially advantageous over the microhardness test as a simple, non-destructive, sensitive technique for the quantification of enamel erosion.
Kim, In-Hye; Son, Jun Sik; Min, Bong Ki; Kim, Young Kyoung; Kim, Kyo-Han; Kwon, Tae-Yub
2016-01-01
Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers' microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (P<0.001). Method 1 was the most sensitive to these changes, followed by surface hardness change measurements and Method 2. This study suggests that ATR-FTIR spectroscopy is potentially advantageous over the microhardness test as a simple, non-destructive, sensitive technique for the quantification of enamel erosion. PMID:27025266
Uritsky, Vadim M.; Ofman, Leon; Davila, Joseph M.; Viall, Nicholeen M.
2013-11-20
A set of co-aligned high-resolution images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory is used to investigate propagating disturbances (PDs) in warm fan loops at the periphery of a non-flaring active region NOAA AR 11082. To measure PD speeds at multiple coronal temperatures, a new data analysis methodology is proposed enabling a quantitative description of subvisual coronal motions with low signal-to-noise ratios of the order of 0.1%. The technique operates with a set of one-dimensional 'surfing' signals extracted from position-time plots of several AIA channels through a modified version of Radon transform. The signals are used to evaluate a two-dimensional power spectral density distribution in the frequency-velocity space that exhibits a resonance in the presence of quasi-periodic PDs. By applying this analysis to the same fan loop structures observed in several AIA channels, we found that the traveling velocity of PDs increases with the temperature of the coronal plasma following the square-root dependence predicted for slow mode magneto-acoustic waves which seem to be the dominating wave mode in the loop structures studied. This result extends recent observations by Kiddie et al. to a more general class of fan loop system not associated with sunspots and demonstrating consistent slow mode activity in up to four AIA channels.
Ubaldini, Adriana L M; Baesso, Mauro L; Sehn, Elizandra; Sato, Francielle; Benetti, Ana R; Pascotto, Renata C
2012-06-01
The purpose of this study was to provide the physicochemical interactions at the interfaces between two commercial etch-&-rinse adhesives and human dentin in a simulated moist bond technique. Six dentin specimens were divided into two groups (n=3) according to the use of two different adhesive systems: (a) 2-hydroxyethylmethacrylate (HEMA) and 4-methacryloxyethyl trimellitate anhydrate (4-META), and (b) HEMA. The Fourier transform infrared photoacoustic spectroscopy was performed before and after dentin treatment with 37% phosphoric acid, with adhesive systems and also for the adhesive systems alone. Acid-conditioning resulted in a decalcification pattern. Adhesive treated spectra subtraction suggested the occurrence of chemical bonding to dentin expressed through modifications of the OH stretching peak (3340 cm(-1)) and symmetric CH stretching (2900 cm(-1)) for both adhesives spectra; a decrease of orthophosphate absorption band (1040 to 970 cm(-1)) for adhesive A and a better resolved complex band formation (1270 to 970 cm(-1)) for adhesive B were observed. These results suggested the occurrence of chemical bonding between sound human dentin and etch-&-rinse adhesives through a clinical typical condition.
Nature of the X(5568) — A critical Laplace sum rule analysis at N2LO
NASA Astrophysics Data System (ADS)
Albuquerque, R.; Narison, S.; Rabemananjara, A.; Rabetiarivony, D.
2016-06-01
We scrutinize recent QCD spectral sum rules (QSSR) results to lowest order (LO) predicting the masses of the BK molecule and (su)(bd¯) four-quark states. We improve these results by adding NLO and N2LO corrections to the PT contributions giving a more precise meaning on the b-quark mass definition used in the analysis. We extract our optimal predictions using Laplace sum rule (LSR) within the standard stability criteria versus the changes of the external free parameters (τ-sum rule variable, tc continuum threshold and subtraction constant μ). The smallness of the higher order PT corrections justifies (a posteriori) the LO order results ⊕ the uses of the ambiguous heavy quark mass to that order. However, our predicted spectra in the range (5173 ˜ 5226) MeV, summarized in Table 7, for exotic hadrons built with four different flavors (buds), do not support some previous interpretations of the D0 candidate,1 X(5568), as a pure molecule or a four-quark state. If experimentally confirmed, it could result from their mixing with an angle: sin 2𝜃 ≈ 0.15. One can also scan the region (2327 ˜ 2444) MeV (where the Ds0∗(2317) might be a good candidate) and the one (5173 ˜ 5226) MeV for detecting these (cuds) and (buds) unmixed exotic hadrons (if any) via, eventually, their radiative or π+hadrons decays.
NASA Astrophysics Data System (ADS)
Choi, Chang-Hyung; Kim, Jongmin; Kang, Sung-Min; Lee, Jinkee; Lee, Chang-Soo
2013-03-01
Monodisperse microspheres play critical roles in many applications such as micro-electromechanical systems (MEMS), chemical release systems, optical materials and various biological applications. Although microfluidic systems have been developed for producing monodisperse microspheres, it still definitely requires pressure driven flow for continuous fluid injection as well as use of surfactant to achieve their uniformity. Here, we present a novel molding method that generates monodisperse microspheres through surface-tension-induced flow. Two immiscible fluids that consist of photocurable monomer and hydrophobic oil are sequentially applied onto the mold. The mold geometry results in Laplace pressure induced droplet formation, and these droplets formed are individually localized into each micromold. Photopolymerization of the droplets allow for the formation of polymer microspheres with narrow size distribution (CV =1.9%). We obtain the microspheres with diameter ranging from 20 to 300 μm by modulating mold dimensions. We provide a synthesis method to produce microspheres in micromolds for various reaction schemes: UV-polymerization, sol-gel reactions and colloidal assemblies.
Use of the augmented Young-Laplace equation to model equilibrium and evaporating extended menisci
DasGupta, S.; Schonberg, J.A.; Kim, I.Y.; Wayner, P.C.Jr. )
1993-05-01
The generic importance of fluid flow and change-of-phase heat transfer in the contact line region of an extended meniscus has led to theoretical and experimental research on the details of these transport processes. Numerical solutions of equilibrium and nonequilibrium models based on the augmented Young-Laplace equation were successfully used to evaluate experimental data for an extended meniscus. The data for the equilibrium and nonequilibrium meniscus profiles were obtained optically using ellipsometry and image processing interferometry. A Taylor series expansion of the fourth-order nonlinear transport model was used to obtain the extremely sensitive initial conditions at the interline. The solid-liquid-vapor Hamaker constants for the systems were obtained from the experimental data. The consistency of the data was demonstrated by using the combining rules to calculate the unknown value of the Hamaker constant for the experimental substrate. The sensitivity of the meniscus profile to small changes in the environment was demonstrated. Both temperature and intermolecular forces need to be included in modeling transport processes in the contact line region because the chemical potential is a function of both temperature and pressure.
Chowdhury, Supriyo; Basu, Arpita; Kundu, Surekha
2014-09-01
In spite of the economic importance of sesame (Sesamum indicum L.) and the recent availability of its genome sequence, a high-frequency transformation protocol is still not available. The only two existing Agrobacterium-mediated transformation protocols that are available have poor transformation efficiencies of less than 2%. In the present study, we report a high-frequency, simple, and reproducible transformation protocol for sesame. Transformation was done using de-embryonated cotyledons via somatic embryogenic stages. All the critical parameters of transformation, like incubation period of explants in pre-regeneration medium prior to infection by Agrobacterium tumefaciens, cocultivation period, concentrations of acetosyringone in cocultivation medium, kanamycin concentration, and concentration of plant hormones, including 6-benzylaminopurine, have been optimized. This protocol is superior to the two existing protocols in its high regeneration and transformation efficiencies. The transformed sesame lines have been tested by PCR, RT-PCR for neomycin phosphotransferase II gene expression, and β-glucuronidase (GUS) assay. The regeneration frequency and transformation efficiency are 57.33 and 42.66%, respectively. T0 and T1 generation transgenic plants were analyzed, and several T1 plants homozygous for the transgenes were obtained.
Jäntschi, Lorentz
2016-01-01
Multiple linear regression analysis is widely used to link an outcome with predictors for better understanding of the behaviour of the outcome of interest. Usually, under the assumption that the errors follow a normal distribution, the coefficients of the model are estimated by minimizing the sum of squared deviations. A new approach based on maximum likelihood estimation is proposed for finding the coefficients on linear models with two predictors without any constrictive assumptions on the distribution of the errors. The algorithm was developed, implemented, and tested as proof-of-concept using fourteen sets of compounds by investigating the link between activity/property (as outcome) and structural feature information incorporated by molecular descriptors (as predictors). The results on real data demonstrated that in all investigated cases the power of the error is significantly different by the convenient value of two when the Gauss-Laplace distribution was used to relax the constrictive assumption of the normal distribution of the error. Therefore, the Gauss-Laplace distribution of the error could not be rejected while the hypothesis that the power of the error from Gauss-Laplace distribution is normal distributed also failed to be rejected. PMID:28090215
Jäntschi, Lorentz; Bálint, Donatella; Bolboacă, Sorana D
2016-01-01
Multiple linear regression analysis is widely used to link an outcome with predictors for better understanding of the behaviour of the outcome of interest. Usually, under the assumption that the errors follow a normal distribution, the coefficients of the model are estimated by minimizing the sum of squared deviations. A new approach based on maximum likelihood estimation is proposed for finding the coefficients on linear models with two predictors without any constrictive assumptions on the distribution of the errors. The algorithm was developed, implemented, and tested as proof-of-concept using fourteen sets of compounds by investigating the link between activity/property (as outcome) and structural feature information incorporated by molecular descriptors (as predictors). The results on real data demonstrated that in all investigated cases the power of the error is significantly different by the convenient value of two when the Gauss-Laplace distribution was used to relax the constrictive assumption of the normal distribution of the error. Therefore, the Gauss-Laplace distribution of the error could not be rejected while the hypothesis that the power of the error from Gauss-Laplace distribution is normal distributed also failed to be rejected.
Hao, Zisu; Malyala, Divya; Dean, Lisa; Ducoste, Joel
2017-04-01
Long Chain Free Fatty Acids (LCFFAs) from the hydrolysis of fat, oil and grease (FOG) are major components in the formation of insoluble saponified solids known as FOG deposits that accumulate in sewer pipes and lead to sanitary sewer overflows (SSOs). A Double Wavenumber Extrapolative Technique (DWET) was developed to simultaneously measure LCFFAs and FOG concentrations in oily wastewater suspensions. This method is based on the analysis of the Attenuated Total Reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) spectrum, in which the absorbance of carboxyl bond (1710cm(-1)) and triglyceride bond (1745cm(-1)) were selected as the characteristic wavenumbers for total LCFFAs and FOG, respectively. A series of experiments using pure organic samples (Oleic acid/Palmitic acid in Canola oil) were performed that showed a linear relationship between the absorption at these two wavenumbers and the total LCFFA. In addition, the DWET method was validated using GC analyses, which displayed a high degree of agreement between the two methods for simulated oily wastewater suspensions (1-35% Oleic acid in Canola oil/Peanut oil). The average determination error of the DWET approach was ~5% when the LCFFA fraction was above 10wt%, indicating that the DWET could be applied as an experimental method for the determination of both LCFFAs and FOG concentrations in oily wastewater suspensions. Potential applications of this DWET approach includes: (1) monitoring the LCFFAs and FOG concentrations in grease interceptor (GI) effluents for regulatory compliance; (2) evaluating alternative LCFFAs/FOG removal technologies; and (3) quantifying potential FOG deposit high accumulation zones in the sewer collection system.
Lin, Shan-Yang; Lin, Hong-Liang; Chi, Ying-Ting; Huang, Yu-Ting; Kao, Chi-Yu; Hsieh, Wei-Hsien
2015-12-30
The amorphous form of a drug has higher water solubility and faster dissolution rate than its crystalline form. However, the amorphous form is less thermodynamically stable and may recrystallize during manufacturing and storage. Maintaining the amorphous state of drug in a solid dosage form is extremely important to ensure product quality. The purpose of this study was to quantitatively determine the amount of amorphous indomethacin (INDO) formed in the Soluplus® solid dispersions using thermoanalytical and Fourier transform infrared (FTIR) spectral curve-fitting techniques. The INDO/Soluplus® solid dispersions with various weight ratios of both components were prepared by air-drying and heat-drying processes. A predominate IR peak at 1683cm(-1) for amorphous INDO was selected as a marker for monitoring the solid state of INDO in the INDO/Soluplus® solid dispersions. The physical stability of amorphous INDO in the INDO/Soluplus® solid dispersions prepared by both drying processes was also studied under accelerated conditions. A typical endothermic peak at 161°C for γ-form of INDO (γ-INDO) disappeared from all the differential scanning calorimetry (DSC) curves of INDO/Soluplus® solid dispersions, suggesting the amorphization of INDO caused by Soluplus® after drying. In addition, two unique IR peaks at 1682 (1681) and 1593 (1591)cm(-1) corresponded to the amorphous form of INDO were observed in the FTIR spectra of all the INDO/Soluplus® solid dispersions. The quantitative amounts of amorphous INDO formed in all the INDO/Soluplus® solid dispersions were increased with the increase of γ-INDO loaded into the INDO/Soluplus® solid dispersions by applying curve-fitting technique. However, the intermolecular hydrogen bonding interaction between Soluplus® and INDO were only observed in the samples prepared by heat-drying process, due to a marked spectral shift from 1636 to 1628cm(-1) in the INDO/Soluplus® solid dispersions. The INDO/Soluplus® solid
NASA Astrophysics Data System (ADS)
Assiongbon, Kankoe A.
2005-07-01
In the work presented in this thesis, the surface sensitive electrochemical techniques of cyclic voltametry (CV), potential step (PS) and Fourier transform impedance spectroscopy (FT-EIS), as well as the optical technique of surface plasmon resonance (SPR), were used to probe a wide variety of surface processes at various metal/liquid interface. Three polycrystalline metals (Au, Ta and Cu) and a Cr-coated gold film were used for these studies in different aqueous environments. A combination of CV with FT-EIS and PS was used to investigate electronic and structural proprieties of a modified bulk electrode of Au. This experimental system involved under potential deposition (UPD) of Bi3+ on Au in a supporting aqueous electrolyte containing ClO-4 . UPD range of Bi3+ was determined, and adsorption kinetics of Bi3+ in the presence of coadsorbing anion, ClO-4 were quantified. Potentiodynamic growth of oxide films of Ta in the following electrolytes NaNO3, NaNO3 + 5wt% H2O2, NaOH and NaOH + 5wt% H2O2 had been investigated. The oxide films were grown in the range -0.1 → +0.4V (high electric field) at a scan rate of 10 mV/s. Time resolved A.C. impedance spectroscopy measurements in the frequency range (0.1--20 KHz) were performed to characterize the surface reactions of oxide formation. The results are interpreted in terms of charge conductivity O2- through the oxide film, and disintegration of H2O2 into OH-. In a high pH medium (pH 12), dissociation of H2O2 was catalytically enhanced. This led to destabilization of the electrogenerated tantalum oxide surface film in the form of a soluble hexatantalate species. In contrast with the electrolytes, NaNO3, NaNO3 + 5wt% H2O2, NaOH, where only the oxide growth was observed, the A.C. impedance spectroscopy measurements in NaOH + 5wt% H 2O2 showed competition between oxide formation and its removal. These results are relevant for chemical slurry design in chemical mechanical polishing (CMP) of Ta. Further investigations were
Solution of fractional kinetic equation by a class of integral transform of pathway type
NASA Astrophysics Data System (ADS)
Kumar, Dilip
2013-04-01
Solutions of fractional kinetic equations are obtained through an integral transform named Pα-transform introduced in this paper. The Pα-transform is a binomial type transform containing many class of transforms including the well known Laplace transform. The paper is motivated by the idea of pathway model introduced by Mathai [Linear Algebra Appl. 396, 317-328 (2005), 10.1016/j.laa.2004.09.022]. The composition of the transform with differential and integral operators are proved along with convolution theorem. As an illustration of applications to the general theory of differential equations, a simple differential equation is solved by the new transform. Being a new transform, the Pα-transform of some elementary functions as well as some generalized special functions such as H-function, G-function, Wright generalized hypergeometric function, generalized hypergeometric function, and Mittag-Leffler function are also obtained. The results for the classical Laplace transform is retrieved by letting α → 1.
Parameter estimation technique for boundary value problems by spline collocation method
NASA Technical Reports Server (NTRS)
Kojima, Fumio
1988-01-01
A parameter-estimation technique for boundary-integral equations of the second kind is developed. The output least-squares identification technique using the spline collocation method is considered. The convergence analysis for the numerical method is discussed. The results are applied to boundary parameter estimations for two-dimensional Laplace and Helmholtz equations.
An empirically derived three-dimensional Laplace resonance in the Gliese 876 planetary system
NASA Astrophysics Data System (ADS)
Nelson, Benjamin E.; Robertson, Paul M.; Payne, Matthew J.; Pritchard, Seth M.; Deck, Katherine M.; Ford, Eric B.; Wright, Jason T.; Isaacson, Howard T.
2016-01-01
We report constraints on the three-dimensional orbital architecture for all four planets known to orbit the nearby M dwarf Gliese 876 based solely on Doppler measurements and demanding long-term orbital stability. Our data set incorporates publicly available radial velocities taken with the ELODIE and CORALIE spectrographs, High Accuracy Radial velocity Planet Searcher (HARPS), and Keck HIgh Resolution Echelle Spectrometer (HIRES) as well as previously unpublished HIRES velocities. We first quantitatively assess the validity of the planets thought to orbit GJ 876 by computing the Bayes factors for a variety of different coplanar models using an importance sampling algorithm. We find that a four-planet model is preferred over a three-planet model. Next, we apply a Newtonian Markov chain Monte Carlo algorithm to perform a Bayesian analysis of the planet masses and orbits using an N-body model in three-dimensional space. Based on the radial velocities alone, we find that a 99 per cent credible interval provides upper limits on the mutual inclinations for the three resonant planets (Φcb < 6.20° for the {c} and {b} pair and Φbe < 28.5° for the {b} and {e} pair). Subsequent dynamical integrations of our posterior sample find that the GJ 876 planets must be roughly coplanar (Φcb < 2.60° and Φbe < 7.87°, suggesting that the amount of planet-planet scattering in the system has been low. We investigate the distribution of the respective resonant arguments of each planet pair and find that at least one argument for each planet pair and the Laplace argument librate. The libration amplitudes in our three-dimensional orbital model support the idea of the outer three planets having undergone significant past disc migration.
NASA Astrophysics Data System (ADS)
Rodrigues, Davi C.; Mauro, Sebastião; de Almeida, Álefe O. F.
2016-10-01
General relativity extensions based on renormalization group effects are motivated by a known physical principle and constitute a class of extended gravity theories that have some unexplored unique aspects. In this work we develop in detail the Newtonian and post-Newtonian limits of a realization called renormalization group extended general relativity (RGGR). Special attention is given to the external potential effect, which constitutes a type of screening mechanism typical of RGGR. In the Solar System, RGGR depends on a single dimensionless parameter ν¯⊙, and this parameter is such that for ν¯⊙=0 one fully recovers GR in the Solar System. Previously this parameter was constrained to be |ν¯ ⊙|≲10-21 , without considering the external potential effect. Here we show that under a certain approximation RGGR can be cast in a form compatible with the parametrized post-Newtonian (PPN) formalism, and we use both the PPN formalism and the Laplace-Runge-Lenz technique to put new bounds on ν¯⊙, either considering or not the external potential effect. With the external potential effect the new bound reads |ν¯ ⊙|≲10-16 . We discuss the possible consequences of this bound on the dark matter abundance in galaxies.
NASA Astrophysics Data System (ADS)
Gelczuk, Ł.; Kamyczek, P.; Płaczek-Popko, E.; Dąbrowska-Szata, M.
2014-09-01
Electrical properties of commercial silicon carbide (SiC) Schottky rectifiers are investigated through the measurement and analysis of the forward current-voltage (I-V) and reverse capacitance-voltage (C-V) characteristics in a large temperature range. Some of devices show distinct discrepancies in specific ranges of their electrical characteristics, especially the excess current dominates at voltage <1 V and temperature <300 K. Standard deep level transient spectroscopy (DLTS) revealed the presence of a single deep-level defect with activation energy of about 0.3 eV, exhibiting the features characteristic for extended defects (e.g. dislocations), such as logarithmic capture kinetics. Furthermore, high-resolution Laplace DLTS showed that this deep level consists actually of three closely spaced levels with activation energies ranging from about 0.26 eV to 0.29 eV. A strong correlation between these two techniques implies that the revealed trap level is due to extended defects surrounded by point traps or clusters of defects. On the basis of obtained specific features of the deep-level defect, it was proposed that this defect is arguably responsible for the observed Schottky barrier inhomogeneities.
In analyses supporting the development of numeric nutrient criteria, multiple statistical techniques can be used to extract critical values from stressor response relationships. However there is little guidance for choosing among techniques, and the extent to which log-transfor...
Rivera, Eugenio J.; Laughlin, Gregory; Vogt, Steven S.; Meschiari, Stefano; Haghighipour, Nader
2010-08-10
Continued radial velocity (RV) monitoring of the nearby M4V red dwarf star GJ 876 with Keck/High Resolution Echelle Spectrograph has revealed the presence of a Uranus-mass fourth planetary companion in the system. The new planet has a mean period of P{sub e} = 126.6 days (over the 12.6-year baseline of the RV observations), and a minimum mass of m{sub e} sin i{sub e} = 12.9 {+-} 1.7 M {sub +}. The detection of the new planet has been enabled by significant improvements to our RV data set for GJ 876. The data have been augmented by 36 new high-precision measurements taken over the past five years. In addition, the precision of all of the Doppler measurements have been significantly improved by the incorporation of a high signal-to-noise template spectrum for GJ 876 into the analysis pipeline. Implementation of the new template spectrum improves the internal rms errors for the velocity measurements taken during 1998-2005 from 4.1 m s{sup -1} to 2.5 m s{sup -1}. Self-consistent, N-body fits to the RV data set show that the four-planet system has an invariable plane with an inclination relative to the plane of the sky of i = 59.{sup 0}5. The fit is not significantly improved by the introduction of a mutual inclination between the planets 'b' and 'c', but the new data do confirm a non-zero eccentricity, e{sub d} = 0.207 {+-} 0.055 for the innermost planet, 'd'. In our best-fit coplanar model, the mass of the new component is m{sub e} = 14.6 {+-} 1.7 M {sub +}. Our best-fitting model places the new planet in a three-body resonance with the previously known giant planets (which have mean periods of P{sub c} = 30.4 and P{sub b} = 61.1 days). The critical argument, {psi}{sub Laplace} = {lambda} {sub c} - 3{lambda} {sub b} + 2{lambda} {sub e}, for the Laplace resonance librates with an amplitude of {Delta}{psi}{sub Laplace} = 40{sup 0} {+-} 13{sup 0} about {psi}{sub Laplace} = 0{sup 0}. Numerical integration indicates that the four-planet system is stable for at least a
NASA Astrophysics Data System (ADS)
Sansottera, Marco; Libert, A.
2013-05-01
Abstract (2,250 Maximum Characters): In this work, we study the secular dynamics of exoplanetary systems consisting of two coplanar planets. In particular, we investigate the effects of the proximity to a mean motion resonance on the secular behavior of the planets. In order to obtain a good description of the secular dynamics, a straightforward method is to include in the unperturbed Hamiltonian the average of the perturbation over the fast angles; this is the so-called approximation at order one in the masses. However, if the system is near a mean motion resonance, the frequencies of the quasi-periodic flow given by this Hamiltonian are quite different from the true ones. Therefore we look for an approximation of the secular Hamiltonian up to order two in the masses, removing the main perturbation depending on the fast angles via a Kolmogorov-like normalization step. The approximation of lowest order in the eccentricities of the secular Hamiltonian is essentially the one considered in the Lagrange-Laplace theory. Following a quite standard procedure, we construct a high order Birkhoff normal form for the Hamiltonian using the Lie series method. Considering the Hamiltonian in non-resonant Birkhoff normal form, the equations of motion take a very simple form, being function of the actions only. So, using the secular frequencies that are easily computed, the long term motion of the planets can be easily integrated analytically. By comparing the semi-analytical results based on the secular approximation, with the dynamics of the complete system, we can better understand whether resonant contributions dominate the evolution of the planets or not. This leads to a simple criterion to discriminate between three categories of systems: : (i) secular systems (HD 11964, HD 74156, HD 134987, HD 163607, HD 12661 and HD 147018); (ii) systems near a mean-motion resonance (HD 11506, HD 177830, HD 9446, HD 169830 and $\\upsilon$ Andromedae); (iii) systems really close to or in a
An Empirically Derived Three-Dimensional Laplace Resonance in the GJ 876 Planetary System
NASA Astrophysics Data System (ADS)
Nelson, Benjamin Earl; Robertson, Paul; Pritchard, Seth
2015-08-01
We report constraints on the three-dimensional orbital architecture for all four planets known to orbit the nearby M dwarf Gliese 876 (=GJ 876) based solely on Doppler measurements and demanding long-term orbital stability. Our dataset incorporates publicly available radial velocities taken with the ELODIE and CORALIE spectrographs, HARPS, and Keck HIRES as well as previously unpublished HIRES RVs. We first quantitatively assess the validity of the planets thought to orbit GJ 876 by computing the Bayes factors for a variety of different coplanar models using an importance sampling algorithm. We confirm that a four-planet model is indeed preferred over a three-planet model. Next, we apply a Newtonian MCMC algorithm (RUN DMC, B. Nelson et al. 2014) to perform a Bayesian analysis of the planet masses and orbits using an n-body model that allows each planet to take on its own orbit in three-dimensional space. Based on the radial velocities alone, the mutual inclinations for the outer three resonant planets are constrained to Φcb = 2.8±1.71.3 degrees for the "c" and "b" pair and Φbe = 10.3±6.35.1 degrees for the "b" and "e" pair. We integrate the equations of motion of a sample of initial conditions drawn from our posterior for 107 years. We identify dynamically unstable models and find that the GJ 876 planets must be roughly coplanar (Φcb = 1.41±0.620.57 degrees) and (Φbe = 3.9±2.01.9 degrees), indicating the amount of planet-planet scattering in the system has been low. We investigate the distribution of the respective resonant arguments of each planet pair and find that at least one resonant argument for each planet pair and the Laplace argument librate. The libration amplitudes in our three-dimensional orbital model supports the idea of the outer-three planets having undergone significant past disk migration.
Laplace-Pressure Actuation of Liquid Metal Devices For Reconfigurable Electromagnetics
NASA Astrophysics Data System (ADS)
Cumby, Brad Lee
it is resilient and shapeable to allow for reconfigurability. In this dissertation, first background information is given on the existing technology for reconfigurable microwave devices and the basic principles that these mechanisms are based upon. Then a new reconfigurable method is introduced that utilizes Laplace pressure. Materials that are associated with using liquid metals are discussed and an overall systematic view is given to provide a set of proof of concepts that are more applied and understandable by electronic designers and engineers. Finally a novel approach to making essential measurements of liquid metal microwave devices is devised and discussed. This dissertation encompasses a complete device design from materials used for fabrication, fabrication methods and measurement processes to provide a knowledge base for designing liquid metal microwave devices.
A Comparison of the Laplace Distribution with an Empirical Model of D062 Demand in Lead Time.
1981-09-01
D062) are based on formu- las originally developed by Presutti and Trepp (1970). These authors consider the problem of determining order quantities and...Presutti and Trepp + -.. .5 Ayb*,OMl ; r4g that demand in a lead time is normally distrib- uted. Howeve;I they then utilize the Laplace distribution to A...i.e. k denotes the number of standard deviations that the demand value x exceeds the expected demand in a lead time. Given (1), - Presutti and Trepp
Characterization of defects created in Cz and epitaxial Si doped with Ga or B using Laplace-DLTS
NASA Astrophysics Data System (ADS)
Nyamhere, Cloud; Deenapanray, P. N. K.; Auret, F. D.; Farlow, F. C.
2006-04-01
We have measured the electrical and annealing properties of defects created in epitaxial and Czochralski-grown Si doped with either B or Ga by electron irradiation using both conventional and Laplace deep level transient spectroscopy (L)-DLTS. With L-DLTS, we have been able to resolve several defects that cannot be resolved using conventional DLTS. L-DLTS provides a new avenue to study defect introduction rates and annealing kinetics in B- and Ga-doped Si. The isochronal annealing behaviour of the defects was also investigated.
NASA Astrophysics Data System (ADS)
Adimurthi; Karthik, A.; Giacomoni, Jacques
2016-06-01
Let n ≥ 2 and Ω ⊂Rn be a bounded domain. Then by Trudinger-Moser embedding, W01,n (Ω) is embedded in an Orlicz space consisting of exponential functions. Consider the corresponding semilinear n-Laplace equation with critical or sub-critical exponential nonlinearity in a ball B (R) with dirichlet boundary condition. In this paper, we prove that under suitable growth conditions on the nonlinearity, there exists an γ0 > 0, and a corresponding R0 (γ0) > 0 such that for all 0 < R
NASA Astrophysics Data System (ADS)
Orazov, Issabek; Besbaev, Gani A.
2016-12-01
In the present work we investigate a nonlocal boundary problem for the Laplace equation in a half-disk, with opposite flows at the part of the boundary. The difference of this problem is the impossibility of direct applying of the Fourier method (separation of variables). Because the corresponding spectral problem for the ordinary differential equation has the system of eigenfunctions not forming a basis. A special system of functions based on these eigenfunctions is constructed. This system has already formed the basis. This fact is used for solving the nonlocal boundary problem. The existence and the uniqueness of classical solution of the problem are proved.
NASA Astrophysics Data System (ADS)
Jiménez-Morillo, Nicasio T.; González-Pérez, José A.; Waggoner, Derek C.; Almendros, Gonzalo; González-Vila, Francisco J.; Hatcher, Patrick G.
2016-04-01
Introduction: Fire is one of the most important modulator factors of the environment and the forest. It is able to induce chemical and biological shifts and these, in turn, can alter the physical properties of soil. Generally, fire affects the most reactive fraction, soil organic matter (SOM) (González-Pérez et al., 2004) resulting in changes to several soil properties and functions. To study changes in SOM following a wildfire, researchers can count on several traditional as well as new analytical techniques. One of the most recently employed techniques is Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). This new powerful ultra-high resolution mass spectral technique, together with graphic interpretation tools such as van Krevelen diagrams (Kim et al, 2003), may be used to shed light on alterations caused by the burning of SOM. The objective of this research is to study fire impacts on SOM, using a sandy soil collected under a Cork oak (Quercus suber) in Doñana National Park, Southwest Spain. that was affected by a wildfire in August 2012. Methods: The impact of fire on SOM was studied in various different sieve fractions (coarse, 1-2 mm, and fine, <0.05 mm) collected in a burned area and an adjacent unburned control site with the same physiographic conditions. Alkaline extracts of SOM from each soil sample were examined using a Bruker Daltonics 12 Tesla Apex Qe FT-ICR-MS equipped with an Apollo II ESI ion source (operating in negative ion mode). The ESI voltages were optimized for each sample, and all spectra were internally calibrated following the procedure of (Sleighter and Hatcher, 2007), after which, peaks were assigned unique molecular formulas using a MatLab script written in house by Dr. Wassim Obeid of Old Dominion University. Results: The van Krevelen diagrams together with the relative intensity of each chemical compound, both obtained by FT-ICR-MS, allowed us to assess SOM quality for each sample and size fractions. The
Development and application of the quasi-potential transformation
Pillay, B.
1992-08-01
The quasi-potential transformation, based on the Kirchhoff transformation, reduces the equations governing mass-transfer in a steady-state, nonconvective electrolytic system into two independent parts. The geometry-specific part involves the solution of Laplace`s equation subject to the relevant boundary conditions. The system-specific part involves the solution of a set of coupled first-order, nonlinear, ordinary differential equations. We develop a theoretical basis for the quasi-potential transformation using potential theory. The major assumption on which the quasi-potential transformation is based is that the concentrations can be written as single-valued functions of the electrostatic potential. We see how the system-specific part of the calculation is developed. Boundary conditions are outlined, and the geometry-specific calculations for the disk and hemisphere electrodes are developed. We combine the system-specific calculations for the binary and acidic copper sulfate solutions with these geometry-specific calculations to obtain complete concentration profiles, potential distributions, and current density distributions for these systems. We also investigate the effect of migration on limiting currents.
Steerable Discrete Cosine Transform
NASA Astrophysics Data System (ADS)
Fracastoro, Giulia; Fosson, Sophie M.; Magli, Enrico
2017-01-01
In image compression, classical block-based separable transforms tend to be inefficient when image blocks contain arbitrarily shaped discontinuities. For this reason, transforms incorporating directional information are an appealing alternative. In this paper, we propose a new approach to this problem, namely a discrete cosine transform (DCT) that can be steered in any chosen direction. Such transform, called steerable DCT (SDCT), allows to rotate in a flexible way pairs of basis vectors, and enables precise matching of directionality in each image block, achieving improved coding efficiency. The optimal rotation angles for SDCT can be represented as solution of a suitable rate-distortion (RD) problem. We propose iterative methods to search such solution, and we develop a fully fledged image encoder to practically compare our techniques with other competing transforms. Analytical and numerical results prove that SDCT outperforms both DCT and state-of-the-art directional transforms.
Steerable Discrete Cosine Transform.
Fracastoro, Giulia; Fosson, Sophie M; Magli, Enrico
2017-01-01
In image compression, classical block-based separable transforms tend to be inefficient when image blocks contain arbitrarily shaped discontinuities. For this reason, transforms incorporating directional information are an appealing alternative. In this paper, we propose a new approach to this problem, namely, a discrete cosine transform (DCT) that can be steered in any chosen direction. Such transform, called steerable DCT (SDCT), allows to rotate in a flexible way pairs of basis vectors, and enables precise matching of directionality in each image block, achieving improved coding efficiency. The optimal rotation angles for SDCT can be represented as solution of a suitable rate-distortion (RD) problem. We propose iterative methods to search such solution, and we develop a fully fledged image encoder to practically compare our techniques with other competing transforms. Analytical and numerical results prove that SDCT outperforms both DCT and state-of-the-art directional transforms.
Transient analysis of Kerr-like phase conjugators using frequency-domain techniques
NASA Astrophysics Data System (ADS)
Fisher, Robert A.; Suydam, B. R.; Feldman, B. J.
1981-06-01
In this paper we develop the interrelationships between the steady-state and transient behavior for cw-pumped Kerr-like conjugators in which the optical Kerr effect is considered to respond instantaneously. We use Laplace-transform techniques to develop an expression for the conjugate response to input pulses of arbitrary form. For stable conjugator operation (in which the cw conjugate reflectivity is finite for all input frequencies), the expression reduces to an antilinear Fourier-transform relationship, which is readily adaptable to computer simulation. The cw filter function of Pepper and Abrams
Transformation optics and cloaking
NASA Astrophysics Data System (ADS)
McCall, Martin
2013-11-01
Invisibility, a long sought-for speculation in science fiction, has been turned into reality in the laboratory through the use of a theoretical technique called Transformation Optics. The principles of transformation optics show that any desired smooth deformation of the electromagnetic field can be implemented exactly by an appropriately engineered metamaterial. All demonstrations of cloaking to date have had limitations, however, reflecting our technological inability to implement the transformation optics algorithm exactly. However, the scientific principles leading to perfect invisibility are now established, and practical improvements on the initial designs are now occurring very rapidly. Most recently, researchers have re-examined transformation optics to include time as well as space, describing and then implementing the concept of a cloak that hides events, a conceptual breakout that promises many new applications. This review describes the general ideas underlying transformation optics, and how the various types of cloak based on these ideas have been implemented practically to date.
NASA Astrophysics Data System (ADS)
Filippi, P. J. T.
1983-11-01
In has been shown that the sound field reflected by the plane boundary of a layered ground can always be described by a specularly reflected wave, and layer potentials. Despite its generality, this representation is not quite suitable for numerical computation. Dealing with a very simple case, Weyl, and later on Ingard and Thomasson, proposed a representation of the solution in which the layer potential terms are replaced by the sum of surface wave and a Laplace type integral. Such an integral is very convenient for numerical purposes. In this paper, it is shown that this kind of representation can be obtained for a very wide class of sound propagation problems above or within layered media: a half-space bounded by a locally reacting surface, a finite layer of porous medium, a porous medium with depth-varying porosity, a thin elastic plate; wave propagation in shallow water with an impedance bottom. Many other applications could be developed.
Darwich, R.; Mani, A. A.
2010-08-15
New substructures of H4 and H5 hole traps have been revealed using Laplace deep-level transient spectroscopy. Our measurements show that the hole traps H4 and H5 can have at least three components for each. Moreover, the activation energies are deduced and the microscopic nature of these substructures is discussed.
Fu, Chi-Yung; Petrich, Loren I.
1997-01-01
An image is compressed by identifying edge pixels of the image; creating a filled edge array of pixels each of the pixels in the filled edge array which corresponds to an edge pixel having a value equal to the value of a pixel of the image array selected in response to the edge pixel, and each of the pixels in the filled edge array which does not correspond to an edge pixel having a value which is a weighted average of the values of surrounding pixels in the filled edge array which do correspond to edge pixels; and subtracting the filled edge array from the image array to create a difference array. The edge file and the difference array are then separately compressed and transmitted or stored. The original image is later reconstructed by creating a preliminary array in response to the received edge file, and adding the preliminary array to the received difference array. Filling is accomplished by solving Laplace's equation using a multi-grid technique. Contour and difference file coding techniques also are described. The techniques can be used in a method for processing a plurality of images by selecting a respective compression approach for each image, compressing each of the images according to the compression approach selected, and transmitting each of the images as compressed, in correspondence with an indication of the approach selected for the image.
ERIC Educational Resources Information Center
Denning, Peter J.; Hiles, John E.
2006-01-01
Transformational Events is a new pedagogic pattern that explains how innovations (and other transformations) happened. The pattern is three temporal stages: an interval of increasingly unsatisfactory ad hoc solutions to a persistent problem (the "mess"), an offer of an invention or of a new way of thinking, and a period of widespread adoption and…
ERIC Educational Resources Information Center
Reeves, Melinda
2006-01-01
The parents of students who attend Decatur High School thought that there was little hope of their kids going on to college. After a year or so in Decatur's reading program, their sons and daughters were both transformed and college bound. In this article, the author describes how Decatur was able to successfully transform their students. Seven…
The Resurrection of Laplace’s Method of Initial Orbit Determination
1983-01-17
astronomical techniques were suitably refined for these new problems with their new observables. The use of laser radars, beacon tracking, electro... lanets of antiquity were the above minus the Earth, plus the Moon and the Sun. I3 these lay in the plane of the ecliptic revolving about the Sun in...The 2’ following year Herschel discovers the first new planet in the history of the world and it fits the above scheme very well. This plus earlier
Trobec, Francesca; Thangadurai, Venkataraman
2008-10-06
Fast oxide ion conducting Ce 1- x M x O 2-delta (M = In, Sm; x = 0.1, 0.2) and Ce 0.8Sm 0.05Ca 0.15O 1.825 were prepared from the corresponding perovskite-like structured materials with nominal chemical composition of BaCe 1- x M x O 3-delta and BaCe 0.8Sm 0.05Ca 0.15O 2.825, respectively, by reacting with CO 2 at 800 degrees C for 12 h. Powder X-ray diffraction (PXRD) analysis showed the formation of fluorite-type CeO 2 and BaCO 3 just after reaction with CO 2. The amount of CO 2 gained per ceramic gram was found to be consistent with the Ba content. The CO 2 reacted samples were washed with dilute HCl and water, and the resultant solid product was characterized structurally and electrically employing various solid-state characterization methods, including PXRD, and alternating current (ac) impedance spectroscopy. The lattice constant of presently prepared Ce 1- x M x O 2-delta and Ce 0.8Sm 0.05Ca 0. 15O 1.825 by a CO 2 capture technique follows the expected ionic radii trend. For example, In-doped Ce 0.9In 0.1O 1.95 (In (3+) (VIII) = 0.92 A) sample showed a fluorite-type cell constant of 5.398(1) A, which is lower than the parent CeO 2 (5.411 A, Ce (4+) (VIII) = 0.97 A). Our attempt to prepare single-phase In-doped CeO 2 samples at 800, 1000, and 1500 degrees C using the ceramic method was unsuccessful. However, we were able to prepare single-phase Ce 0.9In 0.1O 1.95 and Ce 0.8In 0.2O 1.9 by the CO 2 capture method from the corresponding barium perovskites. The PXRD studies showed that the In-doped samples are thermodynamically unstable above 800 degrees C. The ac electrical conductivity studies using Pt electrodes showed the presence of bulk, grain-boundary, and electrode contributions over the investigated temperature range in the frequency range of 10 (-2)-10 (7) Hz. The bulk ionic conductivity and activation energy for the electrical conductivity of presently prepared Sm- and (Sm + Ca)-doped CeO 2 samples shows conductivities similar to those of materials
Rafa, M.J.
1993-04-19
In NiAl, we have succeeded in determining the complete Ginzburg-Landau strain free energy function necessary to model the cubic to tetragonal martensite transformation in a sample of any size. We believe that this is the first time that the parameters of a Ginzburg-Landau functional and the complete strain spinodal for any three-dimensional displacive transformation were used in simulating the transformation near a crack tip under Mode I loading; the transformation pattern and toughening are different from standard transformation toughening theories. Furthermore, the strain spinodal has an approximately conical shape which can be specified by two material dependent experimentally accessible parameters, rather than the ellipsoidal shape in standard theories. Stress induced martensitic transformation in a polycrystalline sample of NiAl was simulated. In the ZrO[sub 2] system, first principles calculations to determine the semi-empirical potentials for simulating the cubic-tetragonal and tetragonal-monoclinic transformations have been started by doing a more elaborate total energy calculation.In the Al[sub 2]0[sub 3] system, we have discovered that the first principles calculations and semi-empirical potentials have just been completed byanother group in England which we will use instead to base our molecular dynamics simulations on.
Stefenelli, Mario; Todt, Juraj; Riedl, Angelika; Ecker, Werner; Müller, Thomas; Daniel, Rostislav; Burghammer, Manfred; Keckes, Jozef
2013-10-01
Novel scanning synchrotron cross-sectional nanobeam and conventional laboratory as well as synchrotron Laplace X-ray diffraction methods are used to characterize residual stresses in exemplary 11.5 µm-thick TiN coatings. Both real and Laplace space approaches reveal a homogeneous tensile stress state and a very pronounced compressive stress gradient in as-deposited and blasted coatings, respectively. The unique capabilities of the cross-sectional approach operating with a beam size of 100 nm in diameter allow the analysis of stress variation with sub-micrometre resolution at arbitrary depths and the correlation of the stress evolution with the local coating microstructure. Finally, advantages and disadvantages of both approaches are extensively discussed.
NASA Technical Reports Server (NTRS)
Walden, H.
1974-01-01
Methods for obtaining approximate solutions for the fundamental eigenvalue of the Laplace-Beltrami operator (also referred to as the membrane eigenvalue problem for the vibration equation) on the unit spherical surface are developed. Two specific types of spherical surface domains are considered: (1) the interior of a spherical triangle, i.e., the region bounded by arcs of three great circles, and (2) the exterior of a great circle arc extending for less than pi radians on the sphere (a spherical surface with a slit). In both cases, zero boundary conditions are imposed. In order to solve the resulting second-order elliptic partial differential equations in two independent variables, a finite difference approximation is derived. The symmetric (generally five-point) finite difference equations that develop are written in matrix form and then solved by the iterative method of point successive overrelaxation. Upon convergence of this iterative method, the fundamental eigenvalue is approximated by iteration utilizing the power method as applied to the finite Rayleigh quotient.
NASA Astrophysics Data System (ADS)
Wie, Bong; Ahn, Jaemyung
2017-03-01
This paper is concerned with a classical yet still mystifying problem regarding multiple roots of the angles-only initial orbit determination (IOD) polynomial equations of Lagrange, Laplace, and Gauss of the form: f( x) = x 8+ a x 6+ b x 3+ c=0 where a, c<0. A possibility of multiple non-spurious roots of this 8th order polynomial equation with b>0 has been extensively treated in the celestial mechanics literature. However, the literature on applied astrodynamics has not treated this multiple-root issue in detail, and not many specific numerical examples with multiple roots are available in the literature. In this paper, a very simple method of determining the correct root from two or three non-spurious roots is presented, which doesn't utilize any a priori knowledge and/or additional observations of the object. The proposed method exploits a simple approximate polynomial equation of the form: g( x) = x 8+ a x 6=0. An approximate polynomial equation, either g( x) = x 8+ c=0 or g( x) = x 8+ a x 6= x 6( x 2+ a) = 0, can also be used for quickly estimating an initial guess of the correct root.
NASA Astrophysics Data System (ADS)
Wie, Bong; Ahn, Jaemyung
2016-09-01
This paper is concerned with a classical yet still mystifying problem regarding multiple roots of the angles-only initial orbit determination (IOD) polynomial equations of Lagrange, Laplace, and Gauss of the form: f(x) = x 8+a x 6+b x 3+c=0 where a,c<0. A possibility of multiple non-spurious roots of this 8th order polynomial equation with b>0 has been extensively treated in the celestial mechanics literature. However, the literature on applied astrodynamics has not treated this multiple-root issue in detail, and not many specific numerical examples with multiple roots are available in the literature. In this paper, a very simple method of determining the correct root from two or three non-spurious roots is presented, which doesn't utilize any a priori knowledge and/or additional observations of the object. The proposed method exploits a simple approximate polynomial equation of the form: g(x) = x 8+a x 6=0. An approximate polynomial equation, either g(x) = x 8+c=0 or g(x) = x 8+a x 6=x 6(x 2+a) = 0, can also be used for quickly estimating an initial guess of the correct root.
Shen, Changqing; Liu, Fang; Wang, Dong; Zhang, Ao; Kong, Fanrang; Tse, Peter W.
2013-01-01
The condition of locomotive bearings, which are essential components in trains, is crucial to train safety. The Doppler effect significantly distorts acoustic signals during high movement speeds, substantially increasing the difficulty of monitoring locomotive bearings online. In this study, a new Doppler transient model based on the acoustic theory and the Laplace wavelet is presented for the identification of fault-related impact intervals embedded in acoustic signals. An envelope spectrum correlation assessment is conducted between the transient model and the real fault signal in the frequency domain to optimize the model parameters. The proposed method can identify the parameters used for simulated transients (periods in simulated transients) from acoustic signals. Thus, localized bearing faults can be detected successfully based on identified parameters, particularly period intervals. The performance of the proposed method is tested on a simulated signal suffering from the Doppler effect. Besides, the proposed method is used to analyze real acoustic signals of locomotive bearings with inner race and outer race faults, respectively. The results confirm that the periods between the transients, which represent locomotive bearing fault characteristics, can be detected successfully. PMID:24253191
Xia, Yan; Hofmann, Hannes; Dennerlein, Frank; Mueller, Kerstin; Schwemmer, Chris; Bauer, Sebastian; Chintalapani, Gouthami; Chinnadurai, Ponraj; Hornegger, Joachim; Maier, Andreas
2014-03-01
It is known that a reduction of the field-of-view in 3-D X-ray imaging is proportional to a reduction in radiation dose. The resulting truncation, however, is incompatible with conventional reconstruction algorithms. Recently, a novel method for region of interest reconstruction that uses neither prior knowledge nor extrapolation has been published, named approximated truncation robust algorithm for computed tomography (ATRACT). It is based on a decomposition of the standard ramp filter into a 2-D Laplace filtering and a 2-D Radon-based residual filtering step. In this paper, we present two variants of the original ATRACT. One is based on expressing the residual filter as an efficient 2-D convolution with an analytically derived kernel. The second variant is to apply ATRACT in 1-D to further reduce computational complexity. The proposed algorithms were evaluated by using a reconstruction benchmark, as well as two clinical data sets. The results are encouraging since the proposed algorithms achieve a speed-up factor of up to 245 compared to the 2-D Radon-based ATRACT. Reconstructions of high accuracy are obtained, e.g., even real-data reconstruction in the presence of severe truncation achieve a relative root mean square error of as little as 0.92% with respect to nontruncated data.
NASA Astrophysics Data System (ADS)
Holota, Petr; Nesvadba, Otakar
2015-04-01
In this paper the reciprocal distance is used for generating Galerkin's approximations in the weak solution of Neumann's problem that has an important role in Earth's gravity field studies. The reciprocal distance has a natural tie to the fundamental solution of Laplace's partial differential equation and in the paper it is represented by means of an expansion into a series of oblate spheroidal harmonics. Subsequently, the gradient vector of the reciprocal distance is constructed. In the computation of its components the expansion mentioned above is employed. The paper then focuses on the scalar product of reciprocal distance gradients in two different points and in particular on a series representation of a volume integral of the scalar product spread over an unbounded domain given by the exterior of an oblate spheroid (oblate ellipsoid of revolution). The integral yields the entries of Galerkin's matrix. The numerical interpretation of all the expansions used as well as the respective software implementation within the OpenCL framework is treated, which concerns also a numerical evaluation of Legendre functions of a real and an imaginary argument. In parallel an approximate closed formula expressing the entries of Galerkin's matrix (with an accuracy up to terms multiplied by the square of numerical eccentricity) is derived for convenience and comparison. The paper is added extensive numerical examples that illustrate the approach applied and demonstrate the accuracy of the derived formulas. Aspects related to practical applications are discussed.
Trigonometric Transforms for Image Reconstruction
1998-06-01
applying trigo - nometric transforms to image reconstruction problems. Many existing linear image reconstruc- tion techniques rely on knowledge of...ancestors. The research performed for this dissertation represents the first time the symmetric convolution-multiplication property of trigo - nometric...Fourier domain. The traditional representation of these filters will be similar to new trigo - nometric transform versions derived in later chapters
NASA Astrophysics Data System (ADS)
Khan, Farrukh I.; Schinn, Dustin S.
2013-08-01
A new business plan that enables policy transformation and resource mobilization at the national and international level, while improving access to resources, will allow the Green Climate Fund to integrate development goals and action on climate change.
Luzinski, Craig
2011-12-01
This month, the director of the Magnet Recognition Program® takes an in-depth look at the Magnet® model component transformational leadership. The author examines the expectations for Magnet organizations around this component. What are the qualities that make a nursing leader truly transformational, and what is the best approach to successfully lead a healthcare organization through today's volatile healthcare environment?
Costanzo, Francesco; Brasseur, James G
2015-03-01
There are strong medical motivations to measure changes in material properties of tubular organs, in vivo and in vitro. The current approach estimates hoop stress from intraluminal pressure using the Laplace law and identifies 'elastic modulus' as the slope of a curve fitted hoop stress plotted against strain data. We show that this procedure is fundamentally flawed because muscle and other soft tissue are closely incompressible, so that the total stress includes a volume-preserving material-dependent hydrostatic response that invalidates the method. Furthermore, we show that the Laplace law incorrectly estimates total stress in biological vessels. However, the great need to estimate elastic modulus leads us to develop an alternative practical method, based on shear stress-strain, i.e. insensitive to nonelastic response from incompressibility, but that uses the same measurement data as the current (incorrect) method. The individual material parameters in the underlying (unknown) constitutive relation combine into an effective shear modulus that is a true measure of elastic response, unaffected by incompressibility and without reference to the Laplace law. Furthermore, our effective shear modulus is determined directly as a function of deformation, rather than as the slope of a fitted curve. We validate our method by comparing effective shear moduli against exact shear moduli for four theoretical materials with different degrees of nonlinearity and numbers of material parameters. To further demonstrate applicability, we reanalyse an in vivo study with our new method and show that it resolves an inconsistent change in modulus with the current method.
Zhao, Hongjuan; Kassama, Yankuba; Young, Michael; Kell, Douglas B.; Goodacre, Royston
2004-01-01
A number of actinomycetes isolates were recovered from coastal sediments in Aberystwyth (Wales, United Kingdom) with standard isolation techniques. Most of them were putatively assigned to the genera Streptomyces and Micromonospora on the basis of their morphological characteristics, and there appeared to be no difference whether the isolation media contained distilled water or seawater. A group of 20 Micromonospora isolates was selected to undergo further polyphasic taxonomic investigation. Three approaches were used to analyze the diversity of these isolates, 16S rDNA sequencing, fluorescent amplified fragment length polymorphism (AFLP), and Fourier transform infrared spectroscopy (FT-IR). The 16S rDNA sequence analysis confirmed that all of these isolates should be classified to the genus Micromonospora, and they were analyzed with a group of other Micromonospora 16S rDNA sequences available from the Ribosomal Database Project. The relationships of the 20 isolates were observed after hierarchical clustering, and almost identical clusters were obtained with these three techniques. This has obvious implications for high-throughput screening for novel actinomycetes because FT-IR spectroscopy, which is a rapid and reliable whole-organism fingerprinting method, can be applied as a very useful dereplication tool to indicate which environmental isolates have been cultured previously. PMID:15528526
A Comparison of FTNMR and FTIR Techniques.
ERIC Educational Resources Information Center
Ahn, Myong-Ku
1989-01-01
Nuclear magnetic resonance and infrared are two spectroscopic methods that commonly use the Fourier transform technique. Discussed are the similarities and differences in the use of the Fourier transform in these two spectroscopic techniques. (CW)
Psychoanalytic transformations.
Riolo, Fernando
2007-12-01
The author describes how Bion took Freud's conception of dreams as a form of thought and used it as the basis of his theory of transformations. Bion developed an expanded theory of 'dream thought', understood as a process of selection and transformation of sensory and emotional experiences. In this theory, the work of analysis is in turn conceived as a process not only of deciphering symbols, of revealing already existing unconscious meanings, but also of symbol production--of a process for generating thoughts and conferring meaning on experiences that have never been conscious and never been repressed because they have never been 'thought'. Analysis, in its specific operational sense, becomes a system of transformation whereby unconscious somatopsychic processes acquire the conditions for representability and become capable of translation into thoughts, words and interpretations. The rules of transformation applied by the patient in his representations and those applied by the analyst in his interpretations have the same importance for the analytic process as those described by Freud for the process of dreaming. The author discusses the broad categories of transformation adduced by Bion (rigid motion, projective, and in hallucinosis) and introduces some further distinctions within them.
Transformation based endorsement systems
NASA Technical Reports Server (NTRS)
Sudkamp, Thomas
1988-01-01
Evidential reasoning techniques classically represent support for a hypothesis by a numeric value or an evidential interval. The combination of support is performed by an arithmetic rule which often requires restrictions to be placed on the set of possibilities. These assumptions usually require the hypotheses to be exhausitive and mutually exclusive. Endorsement based classification systems represent support for the alternatives symbolically rather than numerically. A framework for constructing endorsement systems is presented in which transformations are defined to generate and update the knowledge base. The interaction of the knowledge base and transformations produces a non-monotonic reasoning system. Two endorsement based reasoning systems are presented to demonstrate the flexibility of the transformational approach for reasoning with ambiguous and inconsistent information.
Barboza, Gia Elise
2016-04-01
This study quantifies the spatiotemporal risk of child abuse and neglect in Los Angeles at the census tract level over a recent 4-year period, identifies areas of increased risk, and evaluates the role of structural disadvantage in substantiated child maltreatment referrals. Child maltreatment data on 83,379 child maltreatment cases in 1,678 census tracts spanning 2006-2009 were obtained from the Los Angeles County Department of Children and Family Services. Substantiated referral counts were analyzed across census tracts with Bayesian hierarchical spatial models using integrated nested Laplace approximations. Results showed that the unadjusted yearly rate of child abuse and neglect held fairly steady over the study period decreasing by only 2.57%. However, the temporal term in the spatiotemporal model reflected a downward trend beginning in 2007. High rates of abuse and neglect were predicted by several neighborhood-level measures of structural burden. Every 1-unit decrease in the social vulnerability index reduced the risk of child abuse and neglect by 98.3% (95% CrI = 1.869-2.1042) while every 1-unit increase in the Black-White dissimilarity index decreased child abuse and neglect risk by 70.6%. The interaction of these variables demonstrated the protective effect of racial heterogeneity in socially vulnerable neighborhoods. No such effect was found in neighborhoods characterized by low levels of vulnerability. Population-based child abuse and neglect prevention and intervention efforts should be aided by the characteristics of neighborhoods that demonstrate strong spatial patterns even after accounting for the role of race and place.
An augmented Young-Laplace model of an evaporating meniscus in a micro-channel with high heat flux
NASA Technical Reports Server (NTRS)
Wayner, P. C., Jr.; Plawsky, J.; Schonberg, J. A.; Dasgupta, S.
1993-01-01
High flux evaporations from a steady meniscus formed in a 2 micron channel is modeled using the augmented Young-Laplace equation. The heat flux is found to be a function of the long range van der Waals dispersion force which represents interfacial conditions between heptane and various substrates. Heat fluxes of (1.3-1.6) x 10(exp 6) W/m(exp 2) based on the width of the channel are obtained for heptane completely wetting the substrate at 100 C. Small channels are used to obtain these large fluxes. Even though the real contact angle is 0 deg, the apparent contact angle is found to vary between 24.8 deg and 25.6 deg. The apparent contact angle, which represents viscous losses near the contact line, has a large effect on the heat flow rate because of its effect on capillary suction and the area of the meniscus. The interfacial heat flux is modeled using kinetic theory for the evaporation rate. The superheated state depends on the temperature and the pressure of the liquid phase. The liquid pressure differs from the pressure of the vapor phase due to capillarity and long range van der Waals dispersion forces which are relevant in the ultra think film formed at the leading edge of the meniscus. Important pressure gradients in the thin film cause a substantial apparent contact angle for a complete wetting system. The temperature of the liquid is related to the evaporation rate and to the substrate temperature through the steady heat conduction equation. Conduction in the liquid phase is calculated using finite element analysis except in the vicinity of the thin film. A lubrication theory solution for the thin film is combined with the finite element analysis by the method of matched asymptotic expansions.
ERIC Educational Resources Information Center
Cookson, Peter W., Jr., Ed.; Schneider, Barbara, Ed.
The authors in this book address the issues that relate to the crisis in American education and review some of the proposed solutions. To transform education, schools must be examined as social systems that are interrelated with families, communities, and the world of work. Following the introduction, section 1, "Conditions for Educational…
Transformation & Metamorphosis
ERIC Educational Resources Information Center
Lott, Debra
2009-01-01
The sculptures of Canadian artist Brian Jungen are a great inspiration for a lesson on creating new forms. Jungen transforms found objects into unique creations without fully concealing their original form or purpose. Frank Stella's sculpture series, including "K.132,2007" made of stainless steel and spray paint, is another great example of…
ERIC Educational Resources Information Center
Cronin, C. H.; Feldman, Phillip
1994-01-01
Presents comparisons between the traditional curriculum and the essential learnings curriculum implemented at the Moss Point School District in Moss Point, Mississippi. Describes in detail the curriculum transformation process. Provides insight into the role of technology in the reading/language arts curriculum. (RS)
ERIC Educational Resources Information Center
Berry, John N., III
2007-01-01
The program for the march by librarians on America's capital for the American Library Association (ALA) conference is predictably loaded with lobbying, legislation, and DC tours. It also abounds with professional opportunity and reflects the impact of Leslie Burger, one of the most activist ALA presidents in recent history. Her "Transformation"…
ERIC Educational Resources Information Center
Popham, W. James
2008-01-01
If you're at all skeptical that "formative assessment" is just another buzzword, then here's a book that will change the way you think about the role that formative assessment can play in transforming education into a more powerful and positive process. Renowned expert W. James Popham clarifies what formative assessment really is, why…
Similarity transformed semiclassical dynamics
NASA Astrophysics Data System (ADS)
Van Voorhis, Troy; Heller, Eric J.
2003-12-01
In this article, we employ a recently discovered criterion for selecting important contributions to the semiclassical coherent state propagator [T. Van Voorhis and E. J. Heller, Phys. Rev. A 66, 050501 (2002)] to study the dynamics of many dimensional problems. We show that the dynamics are governed by a similarity transformed version of the standard classical Hamiltonian. In this light, our selection criterion amounts to using trajectories generated with the untransformed Hamiltonian as approximate initial conditions for the transformed boundary value problem. We apply the new selection scheme to some multidimensional Henon-Heiles problems and compare our results to those obtained with the more sophisticated Herman-Kluk approach. We find that the present technique gives near-quantitative agreement with the the standard results, but that the amount of computational effort is less than Herman-Kluk requires even when sophisticated integral smoothing techniques are employed in the latter.
Morris, M.D.
1992-01-01
We have constructed a Hadamard transform Raman microscopic imaging system, and have developed it to a high definition (64K pixel) technique. We have demonstrated multispectral Raman imaging and developed the first three-dimensional (digital confocal) Raman imaging. We have explored the systematic errors in Hadamard multiplexing techniques and developed corrections. We have used our Raman microscope techniques to explore defect distributions on graphite electrodes and damage effects on SERS-activated silver electrodes. We have used the microprobe capabilities of our instrument to investigate the kinetics of polyacrylamide formation in electrolysis capabilities. We have worked closely with a manufacture of holographic displays to develop and incorporate holographic filters and holographic beam splitters into Raman spectrographs and microscopes. Finally, we have developed Hadamard multiplexing techniques for densitometric measurements of protein or nucleic acid blots.
Linear and nonlinear generalized Fourier transforms.
Pelloni, Beatrice
2006-12-15
This article presents an overview of a transform method for solving linear and integrable nonlinear partial differential equations. This new transform method, proposed by Fokas, yields a generalization and unification of various fundamental mathematical techniques and, in particular, it yields an extension of the Fourier transform method.
Chang, C.L.; Fogler, H.S. )
1994-06-01
In the preceding paper in this issue, the influence of the chemical structure of a series of alkylbenzene-derived amphiphiles on the stabilization of asphaltenes was described. In this paper, we present the results of using Fourier transform infrared (FTIR) spectroscopy and small-angle X-ray scattering (SAXS) techniques to study the interaction between asphaltenes and two alkylbenzene-derived amphiphiles, p-alkylphenol and p-alkylbenzenesulfonic acid. FTIR spectroscopy was used to characterize and quantify the acid-base interactions between asphaltenes and amphiphiles. It was found that asphaltenes could hydrogen-bond to p-dodecylphenol amphiphiles. The hydrogen-bonding capacity of asphaltenes was estimated to be 1.6-2.0 mmol/g of asphaltene. On the other hand, the FTIR spectroscopic study indicated that asphaltenes had a complicated acid-base interaction with p-dodecylbenzenesulfonic acid (DBSA) amphiphiles with a stoichiometry of about 1.8 mmol of DBSA/g of asphaltene. The UV/vis spectroscopic study suggested that asphaltenes and DBSA could associate into large electronic conjugated complexes. Physical evidence of the association between asphaltenes and amphiphiles was obtained by SAXS measurements. 27 refs., 10 figs.
Transform methods for precision continuum and control models of flexible space structures
NASA Technical Reports Server (NTRS)
Lupi, Victor D.; Turner, James D.; Chun, Hon M.
1991-01-01
An open loop optimal control algorithm is developed for general flexible structures, based on Laplace transform methods. A distributed parameter model of the structure is first presented, followed by a derivation of the optimal control algorithm. The control inputs are expressed in terms of their Fourier series expansions, so that a numerical solution can be easily obtained. The algorithm deals directly with the transcendental transfer functions from control inputs to outputs of interest, and structural deformation penalties, as well as penalties on control effort, are included in the formulation. The algorithm is applied to several structures of increasing complexity to show its generality.
Experimental validation of a transformation optics based lens for beam steering
Yi, Jianjia; Burokur, Shah Nawaz Lustrac, André de
2015-10-12
A transformation optics based lens for beam control is experimentally realized and measured at microwave frequencies. Laplace's equation is adopted to construct the mapping between the virtual and physical spaces. The metamaterial-based lens prototype is designed using electric LC resonators. A planar microstrip antenna source is used as transverse electric polarized wave launcher for the lens. Both the far field radiation patterns and the near-field distributions have been measured to experimentally demonstrate the beam steering properties. Measurements agree quantitatively and qualitatively with numerical simulations, and a non-narrow frequency bandwidth operation is observed.
Experimental validation of a transformation optics based lens for beam steering
NASA Astrophysics Data System (ADS)
Yi, Jianjia; Burokur, Shah Nawaz; de Lustrac, André
2015-10-01
A transformation optics based lens for beam control is experimentally realized and measured at microwave frequencies. Laplace's equation is adopted to construct the mapping between the virtual and physical spaces. The metamaterial-based lens prototype is designed using electric LC resonators. A planar microstrip antenna source is used as transverse electric polarized wave launcher for the lens. Both the far field radiation patterns and the near-field distributions have been measured to experimentally demonstrate the beam steering properties. Measurements agree quantitatively and qualitatively with numerical simulations, and a non-narrow frequency bandwidth operation is observed.
Smith, James L.; Helenberg, Harold W.; Kilsdonk, Dennis J.
1979-01-01
There is provided an improved RF transformer having a single-turn secondary of cylindrical shape and a coiled encapsulated primary contained within the secondary. The coil is tapered so that the narrowest separation between the primary and the secondary is at one end of the coil. The encapsulated primary is removable from the secondary so that a variety of different capacity primaries can be utilized with one secondary.
NASA Astrophysics Data System (ADS)
Kadic, Muamer; Guenneau, Sébastien; Enoch, Stefan; Huidobro, Paloma A.; Martín-Moreno, Luis; García-Vidal, Francisco J.; Renger, Jan; Quidant, Romain
2012-07-01
Surface plasmons polaritons (SPPs) at metal/dielectric interfaces have raised lots of expectations in the on-going quest towards scaling down optical devices. SPP optics offers a powerful and flexible platform for real two-dimensional integrated optics, capable of supporting both light and electrons. Yet, a full exploitation of the features of SPPs is conditioned by an accurate control of their flow. Most efforts have so far focused on the extrapolation of concepts borrowed from guided optics. This strategy has already led to many important breakthroughs but a fully deterministic control of SPP modes remains a challenge. Recently, the field of optics was stimulated by a novel paradigm, transformation optics, which offers the capability to control light flow in any desired fashion. While it has already significantly contributed to the design of metamaterials with unprecedented optical properties, its versatility offers new opportunities towards a fully deterministic control of SPPs and the design of a new class of plasmonic functionalities. Here, we review recent progress in the application of transformation optics to SPPs. We first briefly describe the theoretical formalism of transformation plasmonics, focusing on its specificities over its three-dimensional optical counterpart. Numerical simulations are then used to illustrate its capability to tame SPP flows at a metal interface patterned with a dielectric load. Finally, we review recent experimental implementations leading to unique SPP functionalities at optical frequencies.
Compression of 3D Point Clouds Using a Region-Adaptive Hierarchical Transform.
De Queiroz, Ricardo; Chou, Philip A
2016-06-01
In free-viewpoint video, there is a recent trend to represent scene objects as solids rather than using multiple depth maps. Point clouds have been used in computer graphics for a long time and with the recent possibility of real time capturing and rendering, point clouds have been favored over meshes in order to save computation. Each point in the cloud is associated with its 3D position and its color. We devise a method to compress the colors in point clouds which is based on a hierarchical transform and arithmetic coding. The transform is a hierarchical sub-band transform that resembles an adaptive variation of a Haar wavelet. The arithmetic encoding of the coefficients assumes Laplace distributions, one per sub-band. The Laplace parameter for each distribution is transmitted to the decoder using a custom method. The geometry of the point cloud is encoded using the well-established octtree scanning. Results show that the proposed solution performs comparably to the current state-of-the-art, in many occasions outperforming it, while being much more computationally efficient. We believe this work represents the state-of-the-art in intra-frame compression of point clouds for real-time 3D video.
NASA Technical Reports Server (NTRS)
Alexandrov, Mikhail D.; Cairns, Brian; Mishchenko, Michael I.
2012-01-01
We present a novel technique for remote sensing of cloud droplet size distributions. Polarized reflectances in the scattering angle range between 135deg and 165deg exhibit a sharply defined rainbow structure, the shape of which is determined mostly by single scattering properties of cloud particles, and therefore, can be modeled using the Mie theory. Fitting the observed rainbow with such a model (computed for a parameterized family of particle size distributions) has been used for cloud droplet size retrievals. We discovered that the relationship between the rainbow structures and the corresponding particle size distributions is deeper than it had been commonly understood. In fact, the Mie theory-derived polarized reflectance as a function of reduced scattering angle (in the rainbow angular range) and the (monodisperse) particle radius appears to be a proxy to a kernel of an integral transform (similar to the sine Fourier transform on the positive semi-axis). This approach, called the rainbow Fourier transform (RFT), allows us to accurately retrieve the shape of the droplet size distribution by the application of the corresponding inverse transform to the observed polarized rainbow. While the basis functions of the proxy-transform are not exactly orthogonal in the finite angular range, this procedure needs to be complemented by a simple regression technique, which removes the retrieval artifacts. This non-parametric approach does not require any a priori knowledge of the droplet size distribution functional shape and is computationally fast (no look-up tables, no fitting, computations are the same as for the forward modeling).
NASA Astrophysics Data System (ADS)
Noppel, M.; Vehkamäki, H.; Winkler, P. M.; Kulmala, M.; Wagner, P. E.
2013-10-01
Based on the results of a previous paper [M. Noppel, H. Vehkamäki, P. M. Winkler, M. Kulmala, and P. E. Wagner, J. Chem. Phys. 139, 134107 (2013)], we derive a thermodynamically consistent expression for reversible or minimal work needed to form a dielectric liquid nucleus of a new phase on a charged insoluble conducting sphere within a uniform macroscopic one- or multicomponent mother phase. The currently available model for ion-induced nucleation assumes complete spherical symmetry of the system, implying that the seed ion is immediately surrounded by the condensing liquid from all sides. We take a step further and treat more realistic geometries, where a cap-shaped liquid cluster forms on the surface of the seed particle. We derive the equilibrium conditions for such a cluster. The equalities of chemical potentials of each species between the nucleus and the vapor represent the conditions of chemical equilibrium. The generalized Young equation that relates contact angle with surface tensions, surface excess polarizations, and line tension, also containing the electrical contribution from triple line excess polarization, expresses the condition of thermodynamic equilibrium at three-phase contact line. The generalized Laplace equation gives the condition of mechanical equilibrium at vapor-liquid dividing surface: it relates generalized pressures in neighboring bulk phases at an interface with surface tension, excess surface polarization, and dielectric displacements in neighboring phases with two principal radii of surface curvature and curvatures of equipotential surfaces in neighboring phases at that point. We also re-express the generalized Laplace equation as a partial differential equation, which, along with electrostatic Laplace equations for bulk phases, determines the shape of a nucleus. We derive expressions that are suitable for calculations of the size and composition of a critical nucleus (generalized version of the classical Kelvin-Thomson equation).
NASA Astrophysics Data System (ADS)
Dildabek, Gulnar; Orazov, Isabek
2016-08-01
In the present paper, we investigate a nonlocal boundary problem for the Laplace equation in a half-disk, with opposite flows at the part of the boundary. The difference of this problem is the impossibility of direct applying of the Fourier method (separation of variables). Because the corresponding spectral problem for the ordinary differential equation has the system of eigenfunctions not forming a basis. A special system of functions based on these eigenfunctions is constructed. This system has already formed the basis. This new basis is used for solving the nonlocal boundary value problem. The existence and the uniqueness of the classical solution of the problem are proved.
NASA Astrophysics Data System (ADS)
Usher, P. D.
1997-12-01
William Shakespeare's Hamlet has much evidence to suggest that the Bard was aware of the cosmological models of his time, specifically the geocentric bounded Ptolemaic and Tychonic models, and the infinite Diggesian. Moreover, Shakespeare describes how the Ptolemaic model is to be transformed to the Diggesian. Hamlet's "transformation" is the reason that Claudius, who personifies the Ptolemaic model, summons Rosencrantz and Guildenstern, who personify the Tychonic. Pantometria, written by Leonard Digges and his son Thomas in 1571, contains the first technical use of the word "transformation." At age thirty, Thomas Digges went on to propose his Perfit Description, as alluded to in Act Five where Hamlet's age is given as thirty. In Act Five as well, the words "bore" and "arms" refer to Thomas' vocation as muster-master and his scientific interest in ballistics. England's leading astronomer was also the father of the poet whose encomium introduced the First Folio of 1623. His oldest child Dudley became a member of the Virginia Company and facilitated the writing of The Tempest. Taken as a whole, such manifold connections to Thomas Digges support Hotson's contention that Shakespeare knew the Digges family. Rosencrantz and Guildenstern in Hamlet bear Danish names because they personify the Danish model, while the king's name is latinized like that of Claudius Ptolemaeus. The reason Shakespeare anglicized "Amleth" to "Hamlet" was because he saw a parallel between Book Three of Saxo Grammaticus and the eventual triumph of the Diggesian model. But Shakespeare eschewed Book Four, creating this particular ending from an infinity of other possibilities because it "suited his purpose," viz. to celebrate the concept of a boundless universe of stars like the Sun.
Conceptual design of a beam steering lens through transformation electromagnetics.
Yi, Jianjia; Burokur, Shah Nawaz; de Lustrac, André
2015-05-18
In this paper, based on transformation electromagnetics, the design procedure of a lens antenna, which steers the radiated beam of a patch array, is presented. Laplace's equation is adopted to construct the mapping between the virtual space and the physical space. The two dimensional (2D) design method can be extended to a potential three-dimensional (3D) realization, and with a proper parameter simplification, the lens can be further realized by common metamaterials or isotropic graded refractive index (GRIN) materials. Full wave simulations are performed to validate the proposed concept. It is observed that by placing the lens on a feeding source, we are able to steer the radiation emitted by the latter source.
NASA Technical Reports Server (NTRS)
McLyman, Colonel Wm. T.
1996-01-01
None given. From first Par: Many spacecraft (S/C) and surface rovers require the transfer of signals and power across rotating interfaces. Science instruments, antennas and solar arrays are elements needing rotary power transfer for certain (S/C) configurations. Delivery of signal and power has mainly been done by using the simplest means, the slip ring approach. This approach, although simple, leaves debris generating noise over a period of time...The rotary transformer is a good alternative to slip rings for signal and power transfer.
Wolfgang, F.; Nicol, J.
1962-11-01
Transformer apparatus is designed for measuring the amount of a paramagnetic substance dissolved or suspended in a diamagnetic liquid. The apparatus consists of a cluster of tubes, some of which are closed and have sealed within the diamagnetic substance without any of the paramagnetic material. The remaining tubes are open to flow of the mix- ture. Primary and secondary conductors are wrapped around the tubes in such a way as to cancel noise components and also to produce a differential signal on the secondaries based upon variations of the content of the paramagnetic material. (AEC)
Development and application of the quasi-potential transformation
Pillay, B.
1992-08-01
The quasi-potential transformation, based on the Kirchhoff transformation, reduces the equations governing mass-transfer in a steady-state, nonconvective electrolytic system into two independent parts. The geometry-specific part involves the solution of Laplace's equation subject to the relevant boundary conditions. The system-specific part involves the solution of a set of coupled first-order, nonlinear, ordinary differential equations. We develop a theoretical basis for the quasi-potential transformation using potential theory. The major assumption on which the quasi-potential transformation is based is that the concentrations can be written as single-valued functions of the electrostatic potential. We see how the system-specific part of the calculation is developed. Boundary conditions are outlined, and the geometry-specific calculations for the disk and hemisphere electrodes are developed. We combine the system-specific calculations for the binary and acidic copper sulfate solutions with these geometry-specific calculations to obtain complete concentration profiles, potential distributions, and current density distributions for these systems. We also investigate the effect of migration on limiting currents.
Kanter, Rosabeth Moss
2008-01-01
Large corporations have long been seen as lumbering, inflexible, bureaucratic--and clueless about global developments. But recently some multinationals seem to be transforming themselves: They're engaging employees, moving quickly, and introducing innovations that show true connection with the world. Harvard Business School's Kanter ventured with a research team inside a dozen global giants--including IBM, Procter & Gamble, Omron, CEMEX, Cisco, and Banco Real--to discover what has been driving the change. After conducting more than 350 interviews on five continents, she and her colleagues came away with a strong sense that we are witnessing the dawn of a new model of corporate power: The coordination of actions and decisions on the front lines now appears to stem from widely shared values and a sturdy platform of common processes and technology, not from top-down decrees. In particular, the values that engage the passions of far-flung workforces stress openness, inclusion, and making the world a better place. Through this shift in what might be called their guidance systems, the companies have become as creative and nimble as much smaller ones, even while taking on social and environmental challenges of a scale that only large enterprises could attempt. IBM, for instance, has created a nonprofit partnership, World Community Grid, through which any organization or individual can donate unused computing power to research projects and see what is being done with the donation in real time. IBM has gained an inspiring showcase for its new technology, helped business partners connect with the company in a positive way, and offered individuals all over the globe the chance to contribute to something big.
Transform coding for space applications
NASA Technical Reports Server (NTRS)
Glover, Daniel
1993-01-01
Data compression coding requirements for aerospace applications differ somewhat from the compression requirements for entertainment systems. On the one hand, entertainment applications are bit rate driven with the goal of getting the best quality possible with a given bandwidth. Science applications are quality driven with the goal of getting the lowest bit rate for a given level of reconstruction quality. In the past, the required quality level has been nothing less than perfect allowing only the use of lossless compression methods (if that). With the advent of better, faster, cheaper missions, an opportunity has arisen for lossy data compression methods to find a use in science applications as requirements for perfect quality reconstruction runs into cost constraints. This paper presents a review of the data compression problem from the space application perspective. Transform coding techniques are described and some simple, integer transforms are presented. The application of these transforms to space-based data compression problems is discussed. Integer transforms have an advantage over conventional transforms in computational complexity. Space applications are different from broadcast or entertainment in that it is desirable to have a simple encoder (in space) and tolerate a more complicated decoder (on the ground) rather than vice versa. Energy compaction with new transforms are compared with the Walsh-Hadamard (WHT), Discrete Cosine (DCT), and Integer Cosine (ICT) transforms.
NASA Astrophysics Data System (ADS)
Khelashvili, A. A.; Nadareishvili, T. P.
2015-01-01
Singular behavior of the Laplace operator in spherical coordinates is investigated. It is shown that in course of transition to the reduced radial wave function in the Schrodinger equation there appears additional term consisting the Dirac delta function, which was unnoted during the full history of physics and mathematics. The possibility of avoiding this contribution from the reduced radial equation is discussed. It is demonstrated that for this aim the necessary and sufficient condition is requirement the fast enough falling of the wave function at the origin. The result does not depend on character of potential—is it regular or singular. The various manifestations and consequences of this observation are considered as well. The corner-stone in our approach is the natural requirement that the solution of the radial equation at the same time must obey to the full equation.
NASA Astrophysics Data System (ADS)
Nyamhere, C.; Das, A. G. M.; Auret, F. D.; Chawanda, A.; Mtangi, W.; Odendaal, Q.; Carr, A.
2009-12-01
We have used deep level transient spectroscopy (DLTS), and Laplace-DLTS to investigate the defects created in antimony doped germanium (Ge) by sputtering with 3 keV Ar ions. Hole traps at EV+0.09 eV and EV+0.31 eV and an electron trap at EC-0.38 eV ( E-center) were observed soon after the sputtering process. Room temperature annealing of the irradiated samples over a period of a month revealed a hole trap at EV+0.26 eV. Above room temperature annealing studies revealed new hole traps at EV+0.27 eV, EV+0.30 eV and EV+0.40 eV.
High Transformer ratios in collinear wakefield accelerators.
Power, J. G.; Conde, M.; Yusof, Z.; Gai, W.; Jing, C.; Kanreykin, A.; Schoessow, P.; High Energy Physics; Euclid Techlabs, LLC
2008-01-01
Based on our previous experiment that successfully demonstrated wakefield transformer ratio enhancement in a 13.625 GHz dielectric-loaded collinear wakefield accelerator using the ramped bunch train technique, we present here a redesigned experimental scheme for even higher enhancement of the efficiency of this accelerator. Design of a collinear wakefield device with a transformer ratio R2, is presented. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2. To match the wavelength of the fundamental mode of the wakefield with the bunch length (sigmaz=2 mm) of the new Argonne wakefield accelerator (AWA) drive gun (where the experiment will be performed), a 26.625 GHz dielectric based accelerating structure is required. This transformer ratio enhancement technique based on our dielectric-loaded waveguide design will result in a compact, high efficiency accelerating structures for future wakefield accelerators.
Split Coil Forms for Rotary Transformers
NASA Technical Reports Server (NTRS)
Mclyman, C. W. T.
1982-01-01
Split cores for rotor and stator windings of rotary transformer mounted around their respective coils (which are in bobbins) and cemented together. This arrangement simplifies winding of stator coil to go in a slot in inner diameter of stator coil. One practical application of rotary transformers fabricated according to this technique is for centrifuges, in which conventional sliprings are of uncertain reliability.
Transforming Research Management Systems at Mayo Clinic
ERIC Educational Resources Information Center
Smith, Steven C.; Gronseth, Darren L.
2011-01-01
In order for research programs at academic medical centers and universities to survive and thrive in the increasingly challenging economic, political and regulatory environment, successful transformation is extremely important. Transformation and quality management techniques are increasingly well established in medical practice organizations. In…
Image Matching Using Generalized Hough Transforms
NASA Technical Reports Server (NTRS)
Davis, L. S.; Hu, F. P.; Hwang, V.; Kitchen, L.
1983-01-01
An image matching system specifically designed to match dissimilar images is described. A set of blobs and ribbons is first extracted from each image, and then generalized Hough transform techniques are used to match these sets and compute the transformation that best registers the image. An example of the application of the approach to one pair of remotely sensed images is presented.
Biometric template transformation: a security analysis
NASA Astrophysics Data System (ADS)
Nagar, Abhishek; Nandakumar, Karthik; Jain, Anil K.
2010-01-01
One of the critical steps in designing a secure biometric system is protecting the templates of the users that are stored either in a central database or on smart cards. If a biometric template is compromised, it leads to serious security and privacy threats because unlike passwords, it is not possible for a legitimate user to revoke his biometric identifiers and switch to another set of uncompromised identifiers. One methodology for biometric template protection is the template transformation approach, where the template, consisting of the features extracted from the biometric trait, is transformed using parameters derived from a user specific password or key. Only the transformed template is stored and matching is performed directly in the transformed domain. In this paper, we formally investigate the security strength of template transformation techniques and define six metrics that facilitate a holistic security evaluation. Furthermore, we analyze the security of two wellknown template transformation techniques, namely, Biohashing and cancelable fingerprint templates based on the proposed metrics. Our analysis indicates that both these schemes are vulnerable to intrusion and linkage attacks because it is relatively easy to obtain either a close approximation of the original template (Biohashing) or a pre-image of the transformed template (cancelable fingerprints). We argue that the security strength of template transformation techniques must consider also consider the computational complexity of obtaining a complete pre-image of the transformed template in addition to the complexity of recovering the original biometric template.
Immersed surfaces and membranes transformations
NASA Astrophysics Data System (ADS)
Kats, E. I.; Monastyrsky, M. I.
2015-06-01
Physical and biological observation methods provide a variety of bilayer membranes’ shapes and their transformations. Besides, the topological and geometrical methods allow us to deduce a classification of all possible membrane surfaces. This double-sided approach leads to a deeper insight into membranes properties. Our goal is to apply an appropriate mathematical technique for classifying vesicles (closed surfaces in mathematical terminology) and for their transformation ways. The problem turned out to be an intricate one, and to our knowledge no mathematical techniques have been applied to its solution. We find that all vesicles can be decomposed in a small number of universality classes generated by a few ‘bricks’: a torus, a screwed torus, and the real projective plane. We consider several ways of transforming membrane surfaces, bearing in mind that they possess an additional extremal property. Our method exploits different constructions of minimal surfaces in S3. We estimate energetic barrier for transformation of minimal membrane surfaces using the so-called doubling procedure. This problem is far from being a pure theoretical exercise. For instance, almost all cells’ biological functions, or tumor progression, are accompanied by apparently singular cell membrane transformations.
Unified framework for systematic loop transformations
Lu, L.C.; Chen, M.
1990-10-01
This paper presents a formal mathematical framework which unifies the existing loop transformations. This framework also includes more general classes of loop transformations, which can extract more parallelism from a class of programs than the existing techniques. We classify schedules into three classes: uniform, subdomain-variant, and statement-variant. Viewing from the degree of parallelism to be gained by loop transformation, the schedules can also be classified as single-sequential level, multiple-sequential level, and mixed schedules. We also illustrate the usefulness of the more general loop transformation with an example program.
The fast parametric slantlet transform with applications
NASA Astrophysics Data System (ADS)
Agaian, Sos S.; Tourshan, Khaled; Noonan, Joseph P.
2004-05-01
Transform methods have played an important role in signal and image processing applications. Recently, Selesnick has constructed the new orthogonal discrete wavelet transform, called the slantlet wavelet, with two zero moments and with improved time localization. The discrete slantlet wavelet transform is carried out by an existing filterbank which lacks a tree structure and has a complexity problem. The slantlet wavelet has been successfully applied in compression and denoising. In this paper, we present a new class of orthogonal parametric fast Haar slantlet transform system where the slantlet wavelet and Haar transforms are special cases of it. We propose designing the slantlet wavelet transform using Haar slantlet transform matrix. A new class of parametric filterbanks is developed. The behavior of the parametric Haar slantlet transforms in signal and image denoising is presented. We show that the new technique performs better than the slantlet wavelet transform in denoising for piecewise constant signals. We also show that the parametric Haar slantlet transform performs better than the cosine and Fourier transforms for grey level images.
Heat storage in alloy transformations
NASA Technical Reports Server (NTRS)
Birchenall, C. E.; Gueceri, S. I.; Farkas, D.; Labdon, M. B.; Nagaswami, N.; Pregger, B.
1981-01-01
The feasibility of using metal alloys as thermal energy storage media was determined. The following major elements were studied: (1) identification of congruently transforming alloys and thermochemical property measurements; (2) development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients; (3) development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase change materials; and (4) identification of materials that could be used to contain the metal alloys. Several eutectic alloys and ternary intermetallic phases were determined. A method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation from data obtained during one continuous experimental test. The method and apparatus are discussed and the experimental results are presented. The development of the numerical modeling method is presented and results are discussed for both salt and metal alloy phase change media.
The Funk transform as a Penrose transform
NASA Astrophysics Data System (ADS)
Bailey, Toby N.; Eastwood, Michael G.; Gover, A. Rod; Mason, Lionel J.
1999-01-01
The Funk transform is the integral transform from the space of smooth even functions on the unit sphere S2[subset or is implied by][open face R]3 to itself defined by integration over great circles. One can regard this transform as a limit in a certain sense of the Penrose transform from [open face C][open face P]2 to [open face C][open face P]*ast;2. We exploit this viewpoint by developing a new proof of the bijectivity of the Funk transform which proceeds by considering the cohomology of a certain involutive (or formally integrable) structure on an intermediate space. This is the simplest example of what we hope will prove to be a general method of obtaining results in real integral geometry by means of complex holomorphic methods derived from the Penrose transform.
Steerable Discrete Fourier Transform
NASA Astrophysics Data System (ADS)
Fracastoro, Giulia; Magli, Enrico
2017-03-01
Directional transforms have recently raised a lot of interest thanks to their numerous applications in signal compression and analysis. In this letter, we introduce a generalization of the discrete Fourier transform, called steerable DFT (SDFT). Since the DFT is used in numerous fields, it may be of interest in a wide range of applications. Moreover, we also show that the SDFT is highly related to other well-known transforms, such as the Fourier sine and cosine transforms and the Hilbert transforms.
Radiogenic cell transformation and carcinogenesis
NASA Technical Reports Server (NTRS)
Yang, T. C.; Georgy, K. A.; Mei, M.; Durante, M.; Craise, L. M.
1995-01-01
Radiation carcinogenesis is one of the major biological effects considered important in the risk assessment for space travel. Various biological model systems, including both cultured cells and animals, have been found useful for studying the carcinogenic effects of space radiations, which consist of energetic electrons, protons and heavy ions. The development of techniques for studying neoplastic cell transformation in culture has made it possible to examine the cellular and molecular mechanisms of radiation carcinogenesis. Cultured cell systems are thus complementary to animal models. Many investigators have determined the oncogenic effects of ionizing and nonionizing radiation in cultured mammalian cells. One of the cell systems used most often for radiation transformation studies is mouse embryonic cells (C3H10T1/2), which are easy to culture and give good quantitative dose-response curves. Relative biological effectiveness (RBE) for heavy ions with various energies and linear energy transfer (LET) have been obtained with this cell system. Similar RBE and LET relationship was observed by investigators for other cell systems. In addition to RBE measurements, fundamental questions on repair of sub- and potential oncogenic lesions, direct and indirect effect, primary target and lesion, the importance of cell-cell interaction and the role of oncogenes and tumor suppressor genes in radiogenic carcinogenesis have been studied, and interesting results have been found. Recently several human epithelial cell systems have been developed, and ionizing radiation have been shown to transform these cells. Oncogenic transformation of these cells, however, requires a long expression time and/or multiple radiation exposures. Limited experimental data indicate high-LET heavy ions can be more effective than low-LET radiation in inducing cell transformation. Cytogenetic and molecular analyses can be performed with cloned transformants to provide insights into basic genetic
Numerical grid generation techniques. [conference
NASA Technical Reports Server (NTRS)
1980-01-01
The state of the art in topology and flow geometry is presented. Solution techniques for partial differential equations are reviewed and included developments in coordinate transformations, conformal mapping, and invariant imbeddings. Applications of these techniques in fluid mechanics, flow geometry, boundary value problems, and fluidics are presented.
Soligno, Giuseppe; Dijkstra, Marjolein; van Roij, René
2014-12-28
Many physical problems require explicit knowledge of the equilibrium shape of the interface between two fluid phases. Here, we present a new numerical method which is simply implementable and easily adaptable for a wide range of problems involving capillary deformations of fluid-fluid interfaces. We apply a simulated annealing algorithm to find the interface shape that minimizes the thermodynamic potential of the system. First, for completeness, we provide an analytical proof that minimizing this potential is equivalent to solving the Young-Laplace equation and the Young law. Then, we illustrate our numerical method showing two-dimensional results for fluid-fluid menisci between vertical or inclined walls and curved surfaces, capillary interactions between vertical walls, equilibrium shapes of sessile heavy droplets on a flat horizontal solid surface, and of droplets pending from flat or curved solid surfaces. Finally, we show illustrative three-dimensional results to point out the applicability of the method to micro- or nano-particles adsorbed at a fluid-fluid interface.
Soligno, Giuseppe; Roij, René van; Dijkstra, Marjolein
2014-12-28
Many physical problems require explicit knowledge of the equilibrium shape of the interface between two fluid phases. Here, we present a new numerical method which is simply implementable and easily adaptable for a wide range of problems involving capillary deformations of fluid-fluid interfaces. We apply a simulated annealing algorithm to find the interface shape that minimizes the thermodynamic potential of the system. First, for completeness, we provide an analytical proof that minimizing this potential is equivalent to solving the Young-Laplace equation and the Young law. Then, we illustrate our numerical method showing two-dimensional results for fluid-fluid menisci between vertical or inclined walls and curved surfaces, capillary interactions between vertical walls, equilibrium shapes of sessile heavy droplets on a flat horizontal solid surface, and of droplets pending from flat or curved solid surfaces. Finally, we show illustrative three-dimensional results to point out the applicability of the method to micro- or nano-particles adsorbed at a fluid-fluid interface.
MR image compression using a wavelet transform coding algorithm.
Angelidis, P A
1994-01-01
We present here a technique for MR image compression. It is based on a transform coding scheme using the wavelet transform and vector quantization. Experimental results show that the method offers high compression ratios with low degradation of the image quality. The technique is expected to be particularly useful wherever storing and transmitting large numbers of images is necessary.
NASA Technical Reports Server (NTRS)
Mclyman, W. T.
1981-01-01
Transformer transmits power and digital data across rotating interface. Array has many parallel data channels, each with potential l megabaud data rate. Ferrite-cored transformers are spaced along rotor; airgap between them reduces crosstalk.
Equations For Rotary Transformers
NASA Technical Reports Server (NTRS)
Salomon, Phil M.; Wiktor, Peter J.; Marchetto, Carl A.
1988-01-01
Equations derived for input impedance, input power, and ratio of secondary current to primary current of rotary transformer. Used for quick analysis of transformer designs. Circuit model commonly used in textbooks on theory of ac circuits.
Chemical Transformation Simulator
The Chemical Transformation Simulator (CTS) is a web-based, high-throughput screening tool that automates the calculation and collection of physicochemical properties for an organic chemical of interest and its predicted products resulting from transformations in environmental sy...
Ying, Z.C.; Plummer, E.W. |
1995-12-31
The technique of optical second harmonic generation is used to study phase transformations at two-dimensional surfaces and interfaces. Examples are given to illustrate that changes in surface symmetry, adsorption configuration, and electronic structure can be detected by this nonlinear optical technique. An oscillatory phase transformation of potassium adsorbed atoms on Al(111) probed by second harmonic generation is analyzed in detail.
Optimal zone coding using the slant transform
Zadiraka, V.K.; Evtushenko, V.N.
1995-03-01
Discrete orthogonal transforms (DOTs) are widely used in digital signal processing, image coding and compression, systems theory, communication, and control. A special representative of the class of DOTs with nonsinusoidal basis functions is the slant transform, which is distinguished by the presence of a slanted vector with linearly decreasing components in its basis. The slant transform of fourth and eighth orders was introduced in 1971 by Enomoto and Shibata especially for efficient representation of the video signal in line sections with smooth variation of brightness. It has been used for television image coding. Pratt, Chen, and Welch generalized the slant transform to vectors of any dimension N = 2{sup n} and two-dimensional arrays, and derived posterior estimates of reconstruction error with zonal image compression (the zones were chosen by trial and error) for various transforms. These estimates show that, for the same N and the same compression ratio {tau}, the slant transform is inferior to the Karhunen - Loeve transform and superior to Walsh and Fourier transforms. In this paper, we derive prior estimates of the reconstruction error for the slant transform in zone coding and suggest an optimal technique for zone selection.
Mechanisms of transformation toughening
Olson, G.B.
1992-02-01
Modelling the thermodynamics and kinetics of isothermal martensitic transformation under stress, transformation toughening in austenitic steels, and dispersed phase transformation plasticity in low alloy steels are discussed briefly in this progress report for Doe Grant DE-FG02-88ER45365.
Maskey, Shila; Geng, Hong; Song, Young-Chul; Hwang, Heejin; Yoon, Young-Jun; Ahn, Kang-Ho; Ro, Chul-Un
2011-08-01
Single-particle characterization of Antarctic aerosols was performed to investigate the impact of marine biogenic sulfur species on the chemical compositions of sea-salt aerosols in the polar atmosphere. Quantitative energy-dispersive electron probe X-ray microanalysis was used to characterize 2900 individual particles in 10 sets of aerosol samples collected between March 12 and 16, 2009 at King Sejong Station, a Korean scientific research station located at King George Island in the Antarctic. Two size modes of particles, i.e., PM(2.5-10) and PM(1.0-2.5), were analyzed, and four types of particles were identified, with sulfur-containing sea-salt particles being the most abundant, followed by genuine sea-salt particles without sulfur species, iron-containing particles, and other species including CaCO(3)/CaMg(CO(3))(2), organic carbon, and aluminosilicates. When a sulfur-containing sea-salt particle showed an atomic concentration ratio of sulfur to sodium of >0.083 (seawater ratio), it is regarded as containing nonsea-salt sulfate (nss-SO(4)(2-)) and/or methanesulfonate (CH(3)SO(3)(-)), which was supported by attenuated total reflection Fourier transform-infrared imaging measurements. These internal mixture particles of sea-salt/CH(3)SO(3)(-)/SO(4)(2-) were very frequently encountered. As nitrate-containing particles were not encountered, and the air-masses for all of the samples originated from the Pacific Ocean (based on 5-day backward trajectories), the oxidation of dimethylsulfide (DMS) emitted from phytoplanktons in the ocean is most likely to be responsible for the formation of the mixed sea-salt/CH(3)SO(3)(-)/SO(4)(2-) particles.
... technique. In: Perry AG, Potter PA, eds. Clinical Nursing Skills and Techniques . 8th ed. Philadelphia, PA: Elsevier Mosby; 2014:chap 8. Read More Stress urinary incontinence Urge incontinence Urinary incontinence Patient Instructions ...
Multibody graph transformations and analysis
2013-01-01
This two-part paper uses graph transformation methods to develop methods for partitioning, aggregating, and constraint embedding for multibody systems. This first part focuses on tree-topology systems and reviews the key notion of spatial kernel operator (SKO) models for such systems. It develops systematic and rigorous techniques for partitioning SKO models in terms of the SKO models of the component subsystems based on the path-induced property of the component subgraphs. It shows that the sparsity structure of key matrix operators and the mass matrix for the multibody system can be described using partitioning transformations. Subsequently, the notions of node contractions and subgraph aggregation and their role in coarsening graphs are discussed. It is shown that the tree property of a graph is preserved after subgraph aggregation if and only if the subgraph satisfies an aggregation condition. These graph theory ideas are used to develop SKO models for the aggregated tree multibody systems. PMID:24288438
Ramkaran, Mohini; Badia, Antonella
2014-08-14
Planar-supported phospholipid bilayers are increasingly used as synthetic membranes for scientific and practical applications. The thermotropic phase properties of supported bilayers are important for recreating biologically relevant situations. Unlike free-standing lipid membranes that undergo one gel-to-fluid or main phase transition, mica-supported single bilayers have been found to undergo two separate leaflet transitions. Although the distinctive nature of the main transition in mica-supported bilayers has been attributed to different effects, determining their relevance has been problematic because vesicle fusion, the technique most widely used to prepare solid-supported bilayer membranes, does not allow one to readily control the lipid surface coverage and molecular density. To circumvent the limitations of the vesicle fusion method and systematically investigate the effects on the individual leaflet transitions of the lipid phase state and molecular density before deposition on the substrate, mica-supported single bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) were prepared using the Langmuir-Blodgett technique. The gel-to-fluid transitions of the bilayer leaflets were tracked by controlled-temperature atomic force microscopy to determine the relative fractions of the gel and fluid phases as a function of temperature. The fraction of solid versus temperature data was fit to the van't Hoff equation to determine the leaflet melting temperatures and transition enthalpies. The phase state and molecular density of the Langmuir monolayer precursor at the transfer pressure of 35 mN m(-1) was found to have a greater effect on the main transition temperature and width of the distal (upper) leaflet than that of the proximal (lower) one. The contributions of substrate-mediated condensation, asymmetric lipid densities, and surface area available for thermal expansion of the bilayer are addressed
NASA Technical Reports Server (NTRS)
Schilling, D. L.
1982-01-01
Bandwidth efficient digital modulation techniques, proposed for use on and/or applied to satellite channels, are reviewed. In a survey of recent works on digital modulation techniques, the performance of several schemes operating in various environments are compared. Topics covered include: (1) quadrature phase shift keying; (2) offset - QPSK and MSK; (3) combined modulation and coding; and (4) spectrally efficient modulation techniques.
Wiese, E.
1998-03-13
Most of the dismantling techniques used in a Decontamination and Dismantlement (D and D) project are taken from conventional demolition practices. Some modifications to the techniques are made to limit exposure to the workers or to lessen the spread of contamination to the work area. When working on a D and D project, it is best to keep the dismantling techniques and tools as simple as possible. The workers will be more efficient and safer using techniques that are familiar to them. Prior experience with the technique or use of mock-ups is the best way to keep workers safe and to keep the project on schedule.
Transformative environmental governance
Chaffin, Brian C.; Garmestani, Ahjond S.; Gunderson, Lance H.; Harm Benson, Melinda; Angeler, David G.; Arnold, Craig Anthony (Tony); Cosens, Barbara; Kundis Craig, Robin; Ruhl, J.B.; Allen, Craig R.
2016-01-01
Transformative governance is an approach to environmental governance that has the capacity to respond to, manage, and trigger regime shifts in coupled social-ecological systems (SESs) at multiple scales. The goal of transformative governance is to actively shift degraded SESs to alternative, more desirable, or more functional regimes by altering the structures and processes that define the system. Transformative governance is rooted in ecological theories to explain cross-scale dynamics in complex systems, as well as social theories of change, innovation, and technological transformation. Similar to adaptive governance, transformative governance involves a broad set of governance components, but requires additional capacity to foster new social-ecological regimes including increased risk tolerance, significant systemic investment, and restructured economies and power relations. Transformative governance has the potential to actively respond to regime shifts triggered by climate change, and thus future research should focus on identifying system drivers and leading indicators associated with social-ecological thresholds.
Norouzi, Parviz; Ganjali, Mohammad Reza; Shirvani-Arani, Simindokht; Mohammadi, Ali
2007-04-01
In this work a novel method for the determination of nortriptyline in flow-injection systems has been developed. The proposed method was used for the fast determination of nortriptyline in its pharmaceutical formulations. The developed technique is very simple, precise, accurate, time saving, and economical, compared to all of the previously reported methods. The effects of various parameters on the sensitivity of the method were investigated. The best performance obtained at pH value of 2, scan rate value of 30 V/s, accumulation potential of 400 mV, and accumulation time of 0.5 s. The proposed method has some advantages over other reported methods such as, no need for the removal of oxygen from the test solution, a subnanomolar detection limit, and finally the method is sufficiently fast for the determination of any such compound, in a wide variety of chromatographic methods. The potential waveform, consisting of the potential steps for cleaning, accumulation and potential ramp of analyte, was continuously applied on an Au disk microelectrode (12.5 microm in radius). The detection limit of the method was 2.0 x 10(-11) M. The relative standard deviation of the method at 1.2 x 10(-8) M was 2.1% for eight runs.
Transformation Toughening of Ceramics
1992-03-01
TRANSFORMATION ZONE SHAPE EFFECTS IN CRACK SHIELDING IN CERIA-PARTIALLY STABILIZED ZIRCONIA (Ce-TZP). ALUMINA COMPOSITES to be published in J. Am. Ceram. Soc. 13 Cl...lS85HWejw TRANSFORMATION ZONE SHAPE EFFECTS ON CRACK SHIELDING IN CERIA-PARTIALLY-STABILIZED ZIRCONIA (Ce-TZP)- ALUMINA S..COMPOSITES Cheng-Sheng Yu...zones in Ce-TZP/Al203 composites, in which the transformation zone sizes were changed significantly by varying the sintering temperature to control
High-Efficiency, Low-Weight Power Transformer
NASA Technical Reports Server (NTRS)
Welsh, J. P.
1986-01-01
Technology for design and fabrication of radically new type of conductioncooled high-power (25 kVA) lightweight transformer having outstanding thermal and electrical characteristics. Fulfills longstanding need for conduction-cooled transformers and magnetics with low internal thermal resistances. Development techniques limited to conductive heat transfer, since other techniques such as liquid cooling, forced liquid cooling, and evaporative cooling of transformers impractical in zero-gravity space environment. Transformer uniquely designed: mechanical structure also serves as thermal paths for conduction cooling of magnetic core and windings.
Program Transformation in HATS
Winter, V.L.
1999-02-24
HATS is a general purpose syntax derivation tree based transformation system in which transformation sequences are described in special purpose language. A powerful feature of this language is that unification is an explicit operation. By making unification explicit, an elegant framework arises in which to express complex application conditions which in turn enables refined control strategies to be realized. This paper gives an overview of HATS, focusing especially on the framework provided by the transformation language and its potential with respect to control and general purpose transformation.
Magnetically Controlled Variable Transformer
NASA Technical Reports Server (NTRS)
Kleiner, Charles T.
1994-01-01
Improved variable-transformer circuit, output voltage and current of which controlled by use of relatively small current supplied at relatively low power to control windings on its magnetic cores. Transformer circuits of this type called "magnetic amplifiers" because ratio between controlled output power and power driving control current of such circuit large. This ratio - power gain - can be as large as 100 in present circuit. Variable-transformer circuit offers advantages of efficiency, safety, and controllability over some prior variable-transformer circuits.
Biochemical transformation of coals
Lin, Mow S.; Premuzic, Eugene T.
1999-03-23
A method of biochemically transforming macromolecular compounds found in solid carbonaceous materials, such as coal is provided. The preparation of new microorganisms, metabolically weaned through challenge growth processes to biochemically transform solid carbonaceous materials at extreme temperatures, pressures, pH, salt and toxic metal concentrations is also disclosed.
Two Different Squeeze Transformations
NASA Technical Reports Server (NTRS)
Han, D. (Editor); Kim, Y. S.
1996-01-01
Lorentz boosts are squeeze transformations. While these transformations are similar to those in squeezed states of light, they are fundamentally different from both physical and mathematical points of view. The difference is illustrated in terms of two coupled harmonic oscillators, and in terms of the covariant harmonic oscillator formalism.
Genetic Transformation of Bacteria.
ERIC Educational Resources Information Center
Moss, Robert.
1991-01-01
An activity in which students transform an ampicillin-sensitive strain of E. coli with a plasmid containing a gene for ampicillin resistance is described. The procedure for the preparation of competent cells and the transformation of competent E. coli is provided. (KR)
NASA Technical Reports Server (NTRS)
Mclyman, W. T.
1977-01-01
Technical memorandum includes transformer area product numbers, which are used to summarize dimensional and electrical properties of C-cores, pot cores, lamination, powder cores, and tape-wound cores. To aid in core selection, comparison of five common core materials is presented to indicate their influence on overall transformer efficiency and weight.
NASA Technical Reports Server (NTRS)
Khanna, S. M.; Urban, E. W. (Inventor)
1979-01-01
A direct current transformer in which the primary consists of an elongated strip of superconductive material, across the ends of which is direct current potential is described. Parallel and closely spaced to the primary is positioned a transformer secondary consisting of a thin strip of magnetoresistive material.
Transformation optics and metamaterials
NASA Astrophysics Data System (ADS)
Chen, Huanyang; Chan, C. T.; Sheng, Ping
2010-05-01
Underpinned by the advent of metamaterials, transformation optics offers great versatility for controlling electromagnetic waves to create materials with specially designed properties. Here we review the potential of transformation optics to create functionalities in which the optical properties can be designed almost at will. This approach can be used to engineer various optical illusion effects, such as the invisibility cloak.
Support Principals, Transform Schools
ERIC Educational Resources Information Center
Aguilar, Elena; Goldwasser, Davina; Tank-Crestetto, Kristina
2011-01-01
The Transformational Coaching Team in Oakland Unified School District provides differentiated, sustained, job-embedded support to the district's school leaders. In this article, members of the team describe how they work with principals to transform the culture of schools. Student achievement data show above-average improvement in schools in which…
Biochemical transformation of coals
Lin, M.S.; Premuzic, E.T.
1999-03-23
A method of biochemically transforming macromolecular compounds found in solid carbonaceous materials, such as coal is provided. The preparation of new microorganisms, metabolically weaned through challenge growth processes to biochemically transform solid carbonaceous materials at extreme temperatures, pressures, pH, salt and toxic metal concentrations is also disclosed. 7 figs.
Metamaterials and Transformation Optics
2011-07-01
Cross-section comparisons of cloaks designed by transformation optical and optical conformal mapping approaches Yaroslav A Urzhumov, Nathan B Kundtz ...B82, 205109, (2010). 9. Electromagnetic design with transformation optics Nathan B. Kundtz , David R. Smith, and John B. Pendry Proceedings of the
Transformative environmental governance
Transformative governance is an approach to environmental governance that has the capacity to respond to, manage, and trigger regime shifts in coupled social-ecological systems (SESs) at multiple scales. The goal of transformative governance is to actively shift degraded SESs to ...
Transformative Learning and Identity
ERIC Educational Resources Information Center
Illeris, Knud
2014-01-01
Transformative learning has usually been defined as transformations of meaning perspectives, frames of reference, and habits of mind--as proposed initially by Jack Mezirow. However, several authors have found this definition too narrow and too cognitively oriented, and Mezirow has later emphasized that emotional and social conditions are also…
Szu, H.; Hsu, C.
1996-12-31
Human sensors systems (HSS) may be approximately described as an adaptive or self-learning version of the Wavelet Transforms (WT) that are capable to learn from several input-output associative pairs of suitable transform mother wavelets. Such an Adaptive WT (AWT) is a redundant combination of mother wavelets to either represent or classify inputs.
Deployment & Market Transformation (Brochure)
Not Available
2012-04-01
NREL's deployment and market transformation (D and MT) activities encompass the laboratory's full range of technologies, which span the energy efficiency and renewable energy spectrum. NREL staff educates partners on how they can advance sustainable energy applications and also provides clients with best practices for reducing barriers to innovation and market transformation.
Enhancing imaging systems using transformation optics.
Smith, David R; Urzhumov, Yaroslav; Kundtz, Nathan B; Landy, Nathan I
2010-09-27
We apply the transformation optical technique to modify or improve conventional refractive and gradient index optical imaging devices. In particular, when it is known that a detector will terminate the paths of rays over some surface, more freedom is available in the transformation approach, since the wave behavior over a large portion of the domain becomes unimportant. For the analyzed configurations, quasi-conformal and conformal coordinate transformations can be used, leading to simplified constitutive parameter distributions that, in some cases, can be realized with isotropic index; index-only media can be low-loss and have broad bandwidth. We apply a coordinate transformation to flatten a Maxwell fish-eye lens, forming a near-perfect relay lens; and also flatten the focal surface associated with a conventional refractive lens, such that the system exhibits an ultra-wide field-of-view with reduced aberration.
Plastid transformation in sugar beet: Beta vulgaris.
De Marchis, Francesca; Bellucci, Michele
2014-01-01
Chloroplast biotechnology has assumed great importance in the past 20 years and, thanks to the numerous advantages as compared to conventional transgenic technologies, has been applied in an increasing number of plant species but still very much limited. Hence, it is of utmost importance to extend the range of species in which plastid transformation can be applied. Sugar beet (Beta vulgaris L.) is an important industrial crop of the temperate zone in which chloroplast DNA is not transmitted trough pollen. Transformation of the sugar beet genome is performed in several research laboratories; conversely sugar beet plastome genetic transformation is far away from being considered a routine technique. We describe here a method to obtain transplastomic sugar beet plants trough biolistic transformation. The availability of sugar beet transplastomic plants should avoid the risk of gene flow between these cultivated genetic modified sugar beet plants and the wild-type plants or relative wild species.
Transforming to Lorentz gauge on de Sitter
Miao, S. P.; Tsamis, N. C.; Woodard, R. P.
2009-12-15
We demonstrate that certain gauge fixing functionals cannot be added to the action on backgrounds such as de Sitter, in which a linearization instability is present. We also construct the field-dependent gauge transformation that carries the electromagnetic vector potential from a convenient, non-de Sitter invariant gauge to the de Sitter invariant, Lorentz gauge. The transformed propagator agrees with the de Sitter invariant result previously found by solving the propagator equation in Lorentz gauge. This shows that the gauge transformation technique will eliminate unphysical breaking of de Sitter invariance introduced by a gauge condition. It is suggested that the same technique can be used to finally resolve the issue of whether or not free gravitons are de Sitter invariant.
Automatic transformations in the inference process
Veroff, R. L.
1980-07-01
A technique for incorporating automatic transformations into processes such as the application of inference rules, subsumption, and demodulation provides a mechanism for improving search strategies for theorem proving problems arising from the field of program verification. The incorporation of automatic transformations into the inference process can alter the search space for a given problem, and is particularly useful for problems having broad rather than deep proofs. The technique can also be used to permit the generation of inferences that might otherwise be blocked and to build some commutativity or associativity into the unification process. Appropriate choice of transformations, and new literal clashing and unification algorithms for applying them, showed significant improvement on several real problems according to several distinct criteria. 22 references, 1 figure.
Data compression techniques and applications
NASA Astrophysics Data System (ADS)
Benelli, G.; Cappellini, V.; Lotti, F.
1980-02-01
The paper reviews several data compression methods for signal and image digital processing and transmission, including both established and more recent techniques. Attention is also given to methods of prediction-interpolation, differential pulse code modulation, delta modulation and transformations. The processing of two dimensional data is also considered, and the results of the application of these techniques to space telemetry and biomedical digital signal processing and telemetry systems are presented.
Transforming Censored Samples and Testing Fit.
2014-09-26
independent U(0,1) sample. Any fixed permutation of this independent -1 sample could then be transformed with R . Theoretically this is a valid...Fit Techniques. New York: Marcel Dekker. [2] Dudewicz, R.J. and Van der Meulan, E.C., (1981). Entropy based tests of uniformity. J. Amer. Statist. Assoc
Producing gapped-ferrite transformer cores
NASA Technical Reports Server (NTRS)
Mclyman, W. T.
1980-01-01
Improved manufacturing techniques make reproducible gaps and minimize cracking. Molded, unfired transformer cores are cut with thin saw and then fired. Hardened semicircular core sections are bonded together, placed in aluminum core box, and fluidized-coated. After winding is run over box, core is potted. Economical method significantly reduces number of rejects.
Fourier transform infrared spectrometery: an undergraduate experiment
NASA Astrophysics Data System (ADS)
Lerner, L.
2016-11-01
Simple apparatus is developed, providing undergraduate students with a solid understanding of Fourier transform (FT) infrared (IR) spectroscopy in a hands on experiment. Apart from its application to measuring the mid-IR spectra of organic molecules, the experiment introduces several techniques with wide applicability in physics, including interferometry, the FT, digital data analysis, and control theory.
Transformational School Leadership Effects on Student Achievement
ERIC Educational Resources Information Center
Sun, Jingping; Leithwood, Kenneth
2012-01-01
Based on a synthesis of unpublished transformational school leadership (TSL) research completed during the last 14 years, this study inquired into the nature of TSL and its effects on student achievement using review methods including standard meta-analysis and vote-counting techniques. Results identify a wider range of TSL practices than…
Digital techniques for ULF wave polarization analysis
NASA Technical Reports Server (NTRS)
Arthur, C. W.
1979-01-01
Digital power spectral and wave polarization analysis are powerful techniques for studying ULF waves in the earth's magnetosphere. Four different techniques for using the spectral matrix to perform such an analysis have been presented in the literature. Three of these techniques are similar in that they require transformation of the spectral matrix to the principal axis system prior to performing the polarization analysis. The differences in the three techniques lie in the manner in which determine this transformation. A comparative study of these three techniques using both simulated and real data has shown them to be approximately equal in quality of performance. The fourth technique does not require transformation of the spectral matrix. Rather, it uses the measured spectral matrix and state vectors for a desired wave type to design a polarization detector function in the frequency domain. The design of various detector functions and their application to both simulated and real data will be presented.
Statistical Evaluation of Time Series Analysis Techniques
NASA Technical Reports Server (NTRS)
Benignus, V. A.
1973-01-01
The performance of a modified version of NASA's multivariate spectrum analysis program is discussed. A multiple regression model was used to make the revisions. Performance improvements were documented and compared to the standard fast Fourier transform by Monte Carlo techniques.
Reducing scalloping in synthetic aperture radar images using a composite image transform
NASA Astrophysics Data System (ADS)
Landmark, Knut; Solberg, Anne H. S.
2015-10-01
In burst mode SAR imaging, echo intensity depends on the target's azimuth position in the antenna pattern. As a result, an amplitude modulation known as scalloping may appear, particularly in ScanSAR images of ocean areas. A denoising method, recently developed for multibeam bathymetry, can be used to reduce residual scalloping in ScanSAR images. The algorithm is analogous to a band-stop filter in the frequency domain. Here, the transform is the composition of an edge detection operator and a discrete Radon transform (DRT). The edge operator accentuates fine-scale intensity changes; the DRT focuses linear features, as each DRT component is the sum of pixel intensities along a linear graph. A descalloping filter is implemented in the DRT domain by suppressing the range direction. The restored image is obtained by applying the inverse composite transform. First, a rapidly converging iterative pseudo-inverse DRT is computed. The edge operator is a spatial filter based on a discrete approximation of the Laplace operator, but modified to make the operator invertible. The method was tested on ocean scene ScanSAR images from the Envisat Advanced Synthetic Aperture Radar. The scalloping effect was significantly reduced, with no apparent distortion or smoothing of physical features.
Anisotropy minimization via least squares method for transformation optics.
Junqueira, Mateus A F C; Gabrielli, Lucas H; Spadoti, Danilo H
2014-07-28
In this work the least squares method is used to reduce anisotropy in transformation optics technique. To apply the least squares method a power series is added on the coordinate transformation functions. The series coefficients were calculated to reduce the deviations in Cauchy-Riemann equations, which, when satisfied, result in both conformal transformations and isotropic media. We also present a mathematical treatment for the special case of transformation optics to design waveguides. To demonstrate the proposed technique a waveguide with a 30° of bend and with a 50% of increase in its output width was designed. The results show that our technique is simultaneously straightforward to be implement and effective in reducing the anisotropy of the transformation for an extremely low value close to zero.
NASA Technical Reports Server (NTRS)
Mclyman, W. T.
1976-01-01
Material was presented to assist transformer designers in the transition from long-used English units to the less familiar metric equivalents. A coordination between the area product numbers ap (product of window and core cross-section areas) and current density J was developed for a given regulation and temperature rise. Straight-line relationships for Ap and Volume, Ap and surface area At and, Ap and weight were developed. These relationships can now be used as new tools to simplify and standardize the process of transformer design. They also made it possible to design transformers of small bulk and volume or to optimize efficiency.
Biolistics Transformation of Wheat
NASA Astrophysics Data System (ADS)
Sparks, Caroline A.; Jones, Huw D.
We present a complete, step-by-step guide to the production of transformed wheat plants using a particle bombardment device to deliver plasmid DNA into immature embryos and the regeneration of transgenic plants via somatic embryogenesis. Currently, this is the most commonly used method for transforming wheat and it offers some advantages. However, it will be interesting to see whether this position is challenged as facile methods are developed for delivering DNA by Agrobacterium tumefaciens or by the production of transformants via a germ-line process (see other chapters in this book).
Undecimated Wavelet Transforms for Image De-noising
Gyaourova, A; Kamath, C; Fodor, I K
2002-11-19
A few different approaches exist for computing undecimated wavelet transform. In this work we construct three undecimated schemes and evaluate their performance for image noise reduction. We use standard wavelet based de-noising techniques and compare the performance of our algorithms with the original undecimated wavelet transform, as well as with the decimated wavelet transform. The experiments we have made show that our algorithms have better noise removal/blurring ratio.
ERIC Educational Resources Information Center
Nalle, Leona
1976-01-01
Describes a course in fiber techniques, which covers design methods involving fibers and fabric, that students in the Art Department at Sleeping Giant Junior High School had the opportunity to learn. (Author/RK)
The Practice of Transformative Pedagogy
ERIC Educational Resources Information Center
Ukpokodu, Omiunota
2009-01-01
The author examined the practice of transformative pedagogy in an undergraduate teacher education program. The research was guided by two questions: What is the impact of transformative pedagogy on fostering preservice teachers' transformative learning? and What practices of transformative pedagogy impact student transformative learning?…
Overview of transformer platform showing three original stepup transformer (center), ...
Overview of transformer platform showing three original step-up transformer (center), steel switchback (right), and modern step-down transformer (foreground), view to northwest - Morony Hydroelectric Facility, Dam and Powerhouse, Morony Dam Road, Great Falls, Cascade County, MT
Personal Transformation: A Group Therapy Program for Saudi Women.
ERIC Educational Resources Information Center
Pharaon, Nora Alarifi
A personal transformation group therapy program was designed to help Saudi women function more effectively in their daily lives. The major cognitive idea of these groups was to enable women to better understand their thinking patterns so that they could learn techniques to change. Personal transformation group topics included: Self-Esteem;…
Transpersonal Psychology: Facilitating Transformation in Outdoor Experiential Education.
ERIC Educational Resources Information Center
Brown, Michael H.
1989-01-01
Explores how outdoor experiential education can facilitate personal growth and transformation by balancing adventure-based activities with inner-directed processes. Discusses transpersonal psychology and research on consciousness and brain functions relevant to the process of transformation. Describes a specific technique to access deeper levels…
On-line textile quality control using optical Fourier transforms
NASA Astrophysics Data System (ADS)
Castellini, C.; Francini, F.; Longobardi, G.; Tiribilli, B.; Sansoni, P.
Fourier transformation and spatial filtering offer the possibility of detecting structural defects in a fabric. In this paper a method based on an optical Fourier transform technique during the weaving process is described. Significant variations in the Fourier pattern occurring in the presence of defective fabric are recognised with a CCD sensor joined to an electronic hardware system performing a simple algorithm.
Optimization of distribution transformer efficiency characteristics. Final report, March 1979
Not Available
1980-06-01
A method for distribution transformer loss evaluation was derived. The total levalized annual cost method was used and was extended to account properly for conditions of energy cost inflation, peak load growth, and transformer changeout during the evaluation period. The loss costs included were the no-load and load power losses, no-load and load reactive losses, and the energy cost of regulation. The demand and energy components of loss costs were treated separately to account correctly for the diversity of load losses and energy cost inflation. The complete distribution transformer loss evaluation equation is shown, with the nomenclature and definitions for the parameters provided. Tasks described are entitled: Establish Loss Evaluation Techniques; Compile System Cost Parameters; Compile Load Parameters and Loading Policies; Develop Transformer Cost/Performance Relationship; Define Characteristics of Multiple Efficiency Transformer Package; Minimize Life Cycle Cost Based on Single Efficiency Characteristic Transformer Design; Minimize Life Cycle Cost Based on Multiple Efficiency Characteristic Transformer Design; and Interpretation.
NASA Technical Reports Server (NTRS)
Mclyman, W. T.
1977-01-01
In space, power system transformer components are frequently the heaviest and bulkiest items in the power conversion circuit. They also have a significant effect upon the overall performance and efficiency of the system. Accordingly, the design of such transformers has an important effect on overall system weight, power-inversion efficiency, and cost. Relationships were between the parameters used by transformer designers that can be used as new tools to standardize and simplify transformer design. They can be used to optimize the design either for small size and weight or efficiency. The metric system of units, rather than the familiar English units, is used; however, material is presented to assist the reader in the transition from one system to the other.
ERIC Educational Resources Information Center
Bannon, Thomas J.
1991-01-01
Discussed are several different transformations based on the generation of fractals including self-similar designs, the chaos game, the koch curve, and the Sierpinski Triangle. Three computer programs which illustrate these concepts are provided. (CW)
A Classical Science Transformed.
ERIC Educational Resources Information Center
Kovalevsky, Jean
1979-01-01
Describes how satellites and other tools of space technology have transformed classical geodesy into the science of space geodynamics. The establishment and the activities of the French Center for Geodynamic and Astronomical Research Studies (CERGA) are also included. (HM)
Proof in Transformation Geometry
ERIC Educational Resources Information Center
Bell, A. W.
1971-01-01
The first of three articles showing how inductively-obtained results in transformation geometry may be organized into a deductive system. This article discusses two approaches to enlargement (dilatation), one using coordinates and the other using synthetic methods. (MM)
Programmable convolution via the chirp Z-transform with CCD's
NASA Technical Reports Server (NTRS)
Buss, D. D.
1977-01-01
Technique filtering by convolution in frequency domain rather than in time domain presents possible solution to problem of programmable transversal filters. Process is accomplished through utilization of chip z-transform (CZT) with charge-coupled devices
Coherent optical generation of Hartley transform of real images
NASA Astrophysics Data System (ADS)
Li, Y.; Eichmann, G.
1985-12-01
A new method to generate optical Hartley transform (OHT) for 2D real images is proposed. The method is based on polarization encoding of the coherent optical beam. Different coherent optical image processing techniques are discussed.
Agrobacterium persistence in plant tissues after transformation.
Cubero, Jaime; López, María M
2005-01-01
Agrobacterium spp. are routinely used in plant transformation to introduce genes of interest in valuable economic species. However, several agrobacteria species are also plant pathogens with ability to survive in different environments including the inner part of the plants. To avoid the release of genetic modified bacteria a successful plant transformation protocol must include the total elimination of agrobacteria by the use of antibiotics. Because sometimes these antibiotics failed in removing the bacteria entirely, confirmation of agrobacteria absence after plant transformation and regeneration is required. Different methodologies can be used for this purpose: isolation techniques followed by identification are used if detection of viable and culturable bacteria is necessary and techniques based on the polymerase chain reaction can be used to detect agrobacteria independently of their physiological state. Here we present several protocols to detect Agrobacterium in tissues of transformed plants as well as methods to identify the strains isolated. These identification methods can help to elucidate if they are the engineered bacteria used in the transformation process or just part of the natural endophytic microbiota.
Multispectral multisensor image fusion using wavelet transforms
Lemeshewsky, George P.
1999-01-01
Fusion techniques can be applied to multispectral and higher spatial resolution panchromatic images to create a composite image that is easier to interpret than the individual images. Wavelet transform-based multisensor, multiresolution fusion (a type of band sharpening) was applied to Landsat thematic mapper (TM) multispectral and coregistered higher resolution SPOT panchromatic images. The objective was to obtain increased spatial resolution, false color composite products to support the interpretation of land cover types wherein the spectral characteristics of the imagery are preserved to provide the spectral clues needed for interpretation. Since the fusion process should not introduce artifacts, a shift invariant implementation of the discrete wavelet transform (SIDWT) was used. These results were compared with those using the shift variant, discrete wavelet transform (DWT). Overall, the process includes a hue, saturation, and value color space transform to minimize color changes, and a reported point-wise maximum selection rule to combine transform coefficients. The performance of fusion based on the SIDWT and DWT was evaluated with a simulated TM 30-m spatial resolution test image and a higher resolution reference. Simulated imagery was made by blurring higher resolution color-infrared photography with the TM sensors' point spread function. The SIDWT based technique produced imagery with fewer artifacts and lower error between fused images and the full resolution reference. Image examples with TM and SPOT 10-m panchromatic illustrate the reduction in artifacts due to the SIDWT based fusion.
Series Transmission Line Transformer
Buckles, Robert A.; Booth, Rex; Yen, Boris T.
2004-06-29
A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.
Metamaterials and Transformation Optics
2014-01-31
research is extend the analytical work in transformation optics (relating complex systems to simpler systems with the same spectral properties ) to... optics which via a transformation relates complex systems to simpler systems possessed of the same spectral properties . One good example is to be...mediated by the quantum fluctuations in electron density at the metal surfaces and are the most long ranged forces between nanoparticles . Fig. 1(a
25. VIEW, LOOKING SOUTHWEST INSIDE TRANSFORMER ROOM, SHOWING TRANSFORMERS AND ...
25. VIEW, LOOKING SOUTHWEST INSIDE TRANSFORMER ROOM, SHOWING TRANSFORMERS AND KNIFE SWITCHES - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA
Chao, T.T.; Sanzolone, R.F.
1992-01-01
Sample decomposition is a fundamental and integral step in the procedure of geochemical analysis. It is often the limiting factor to sample throughput, especially with the recent application of the fast and modern multi-element measurement instrumentation. The complexity of geological materials makes it necessary to choose the sample decomposition technique that is compatible with the specific objective of the analysis. When selecting a decomposition technique, consideration should be given to the chemical and mineralogical characteristics of the sample, elements to be determined, precision and accuracy requirements, sample throughput, technical capability of personnel, and time constraints. This paper addresses these concerns and discusses the attributes and limitations of many techniques of sample decomposition along with examples of their application to geochemical analysis. The chemical properties of reagents as to their function as decomposition agents are also reviewed. The section on acid dissolution techniques addresses the various inorganic acids that are used individually or in combination in both open and closed systems. Fluxes used in sample fusion are discussed. The promising microwave-oven technology and the emerging field of automation are also examined. A section on applications highlights the use of decomposition techniques for the determination of Au, platinum group elements (PGEs), Hg, U, hydride-forming elements, rare earth elements (REEs), and multi-elements in geological materials. Partial dissolution techniques used for geochemical exploration which have been treated in detail elsewhere are not discussed here; nor are fire-assaying for noble metals and decomposition techniques for X-ray fluorescence or nuclear methods be discussed. ?? 1992.
Natural competence for transformation.
Blokesch, Melanie
2016-11-07
While most molecular biologists are familiar with the artificial transformation of bacteria in the context of laboratory cloning experiments, natural competence for transformation refers to a specific physiological state in which prokaryotes are able to take up genetic material from their surroundings. Occasionally, such absorbed DNA is recombined into the organism's own genome, resulting in natural transformation (Figure 1). As a consequence, natural competence for transformation is considered a primary mode of horizontal gene transfer (HGT) in prokaryotes, together with conjugation (direct cell to cell transfer of DNA via a specialized conjugal pilus) and phage transduction (DNA transfer mediated by viruses). HGT plays a major role in bacterial evolution, and past research has demonstrated that HGT, including natural competence for transformation, contributes to the emergence of pathogens and the spread of virulence factors. Indeed, Frederick Griffith discovered natural competence for transformation in 1928 while he was investigating the exchange of pathogenic traits in pneumococci. Due to the increase in the abundance and spread of multidrug-resistant microbes, research on HGT is even more important today than ever before.
Magnetic tunnel junction pattern technique
NASA Astrophysics Data System (ADS)
Chen, Eugene; Schwarz, Benjamin; Choi, Chang Ju; Kula, Witold; Wolfman, Jerome; Ounadjela, Kamel; Geha, Sam
2003-05-01
We have developed a magnetic tunnel junction (MTJ) pattern technique that involves transforming the magnetic layer above the tunnel barrier in unwanted areas into an insulator, thus providing insulation between different MTJ devices without suffering common tunnel barrier shorting problems. With this technique, 90%-100% yielding MTJ devices have been observed. MTJ results using this process are superior to an etching based process. Switching distribution of patterned magnetic bits is also narrower using this novel technique. Process control and the ability to stop on the tunnel barrier have been demonstrated.
Activities: Geometric Transformations. Part 2.
ERIC Educational Resources Information Center
Eddins, Susan K.; And Others
1994-01-01
Presents a lesson that connects basic transformational concepts with transformations on a Cartesian-coordinate system, culminating with the application of matrix operations to perform geometric transformations. Includes reproducible student worksheets and assessment activities. (MKR)
Relativistic Transformation of Solid Angle.
ERIC Educational Resources Information Center
McKinley, John M.
1980-01-01
Rederives the relativistic transformations of light intensity from compact sources (stars) to show where and how the transformation of a solid angle contributes. Discusses astrophysical and other applications of the transformations. (Author/CS)
Automatic recognition of biological shapes using the Hotelling transform.
Sanchez-Marin, F J
2001-03-01
We present two contour-based techniques, for computerized object recognition that avoid the difficulties due to translations, rotations and scaling. Our techniques do not require any shape representation. The first technique uses the scale-space filtered coordinate functions of contours and their "largest diameters". The second, uses the Hotelling transform of the vector representations of the points of contours. We applied both techniques to recognize human corneal endothelial cells, embedded in a sample of tissue. The results obtained using the Hotelling transform represent a considerable improvement when compared to those previously obtained using the coordinate functions, the curvature function and Fourier descriptors as representations of shape.
Fincham, J R
1989-01-01
Transformation with exogenous deoxyribonucleic acid (DNA) now appears to be possible with all fungal species, or at least all that can be grown in culture. This field of research is at present dominated by Saccharomyces cerevisiae and two filamentous members of the class Ascomycetes, Aspergillus nidulans and Neurospora crassa, with substantial contributions also from fission yeast (Schizosaccharomyces pombe) and another filamentous member of the class Ascomycetes, Podospora anserina. However, transformation has been demonstrated, and will no doubt be extensively used, in representatives of most of the main fungal classes, including Phycomycetes, Basidiomycetes (the order Agaricales and Ustilago species), and a number of the Fungi Imperfecti. The list includes a number of plant pathogens, and transformation is likely to become important in the analysis of the molecular basis of pathogenicity. Transformation may be maintained either by using an autonomously replicating plasmid as a vehicle for the transforming DNA or through integration of the DNA into the chromosomes. In S. cerevisiae and other yeasts, a variety of autonomously replicating plasmids have been used successfully, some of them designed for use as shuttle vectors for Escherichia coli as well as for yeast transformation. Suitable plasmids are not yet available for use in filamentous fungi, in which stable transformation is dependent on chromosomal integration. In Saccharomyces cerevisiae, integration of transforming DNA is virtually always by homology; in filamentous fungi, in contrast, it occurs just as frequently at nonhomologous (ectopic) chromosomal sites. The main importance of transformation in fungi at present is in connection with gene cloning and the analysis of gene function. The most advanced work is being done with S. cerevisiae, in which the virtual restriction of stable DNA integration to homologous chromosome loci enables gene disruption and gene replacement to be carried out with greater
Reverse ray tracing for transformation optics.
Hu, Chia-Yu; Lin, Chun-Hung
2015-06-29
Ray tracing is an important technique for predicting optical system performance. In the field of transformation optics, the Hamiltonian equations of motion for ray tracing are well known. The numerical solutions to the Hamiltonian equations of motion are affected by the complexities of the inhomogeneous and anisotropic indices of the optical device. Based on our knowledge, no previous work has been conducted on ray tracing for transformation optics with extreme inhomogeneity and anisotropicity. In this study, we present the use of 3D reverse ray tracing in transformation optics. The reverse ray tracing is derived from Fermat's principle based on a sweeping method instead of finding the full solution to ordinary differential equations. The sweeping method is employed to obtain the eikonal function. The wave vectors are then obtained from the gradient of that eikonal function map in the transformed space to acquire the illuminance. Because only the rays in the points of interest have to be traced, the reverse ray tracing provides an efficient approach to investigate the illuminance of a system. This approach is useful in any form of transformation optics where the material property tensor is a symmetric positive definite matrix. The performance and analysis of three transformation optics with inhomogeneous and anisotropic indices are explored. The ray trajectories and illuminances in these demonstration cases are successfully solved by the proposed reverse ray tracing method.
Agrobacterium-mediated transformation of Fusarium proliferatum.
Bernardi-Wenzel, J; Quecine, M C; Azevedo, J L; Pamphile, J A
2016-06-03
Fusarium proliferatum is an important pathogen that is associated with plant diseases and primarily affects aerial plant parts by producing different mycotoxins, which are toxic to humans and animals. Within the last decade, this fungus has also been described as one of the causes of red root rot or sudden death syndrome in soybean, which causes extensive damage to this crop. This study describes the Agrobacterium tumefaciens-mediated transformation of F. proliferatum as a tool for the disruption of pathogenicity genes. The genetic transformation was performed using two binary vectors (pCAMDsRed and pFAT-GFP) containing the hph (hygromycin B resistance) gene as a selection marker and red and green fluorescence, respectively. The presence of acetosyringone and the use of filter paper or nitrocellulose membrane were evaluated for their effect on the transformation efficiency. A mean processing rate of 94% was obtained with 96 h of co-cultivation only in the presence of acetosyringone and the use of filter paper or nitrocellulose membrane did not affect the transformation process. Hygromycin B resistance and the presence of the hph gene were confirmed by PCR, and fluorescence due to the expression of GFP and DsRed protein was monitored in the transformants. A high rate of mitotic stability (95%) was observed. The efficiency of Agrobacterium-mediated transformation of F. proliferatum allows the technique to be used for random insertional mutagenesis studies and to analyze fungal genes involved in the infection process.
IPv4 to IPv6 Transformation Schemes
NASA Astrophysics Data System (ADS)
Miyakawa, Shin
According to the recent observations of IPv4 (Internet Protocol version 4) address allocation status, it will be running out within few years. Consequently, to ensure the continuous extension of the Internet operation, introducing IPv6 (Internet Protocol version 6) protocol is surely needed. But at the same time, such transformation must be “smooth” for every Internet users and be compatible with today's IPv4 based practices. This paper describes several techniques and usage scenario which are discussed mainly in the IETF — Internet Engineering Task Force — and tried to be implemented as prototype products to transform today's Internet towards the IPv6 based one.
Nonprojective Transformations In Optics
NASA Astrophysics Data System (ADS)
Cornwell, Dean F.
1982-02-01
Optical systems that perform non-projective transformations are rarely synthesized by intent. Most systems familiar in practice are designed to provide the closest approximation to a projective transformation that is allowed by physics, technology, or economy. The advent of the laser brings many new applications for optical transformations - the non-projective variety being a late-comer. Requirements in the fields of laser materials processing, optical data processing, high energy lasers, and laser fusion, just to name those areas already penetrated, lead one to consideration for unconventional grooming of wavefront irradiance profiles. Transformations such as changing a wavefront irradiance distribution from flat-like to gaussian-like, or vice versa, or changing the wavefront area obscuration while maintaining its focusability, are typical examples of applications gaining an increasing interest. Following the laws of geometrical optics, yet violating certain fundamental rules of imaging, the present paper develops principles of design and analysis of non-projective transformations in optics, and explores one possible application.
Discrete Fourier Transform in a Complex Vector Space
NASA Technical Reports Server (NTRS)
Dean, Bruce H. (Inventor)
2015-01-01
An image-based phase retrieval technique has been developed that can be used on board a space based iterative transformation system. Image-based wavefront sensing is computationally demanding due to the floating-point nature of the process. The discrete Fourier transform (DFT) calculation is presented in "diagonal" form. By diagonal we mean that a transformation of basis is introduced by an application of the similarity transform of linear algebra. The current method exploits the diagonal structure of the DFT in a special way, particularly when parts of the calculation do not have to be repeated at each iteration to converge to an acceptable solution in order to focus an image.
Heat storage in alloy transformations
NASA Technical Reports Server (NTRS)
Birchenall, C. E.
1980-01-01
The feasibility of using metal alloys as thermal energy storage media was investigated. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases were determined. A new method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation. The method and apparatus are discussed and the experimental results are presented for aluminum and two aluminum-eutectic alloys. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide was identified as a promising containment material and surface-coated iron alloys were also evaluated. System considerations that are pertinent if alloy eutectics are used as thermal energy storage media are discussed. Potential applications to solar receivers and industrial furnaces are illustrated schematically.
NASA Astrophysics Data System (ADS)
Budinich, Marco
2016-07-01
We begin showing that for even dimensional vector spaces V all automorphisms of their Clifford algebras are inner. So all orthogonal transformations of V are restrictions to V of inner automorphisms of the algebra. Thus under orthogonal transformations P and T—space and time reversal—all algebra elements, including vectors v and spinors φ, transform as v → xvx-1 and φ → xφx-1 for some algebra element x. We show that while under combined PT spinor φ → xφx-1 remains in its spinor space, under P or T separately φ goes to a different spinor space and may have opposite chirality. We conclude with a preliminary characterization of inner automorphisms with respect to their property to change, or not, spinor spaces.
Translating and Transforming Care
Gillespie, Alex; Moore, Helen
2015-01-01
This article examines how the Disability Living Allowance claim form, used in the United Kingdom to allocate £13 billion of disability benefits, translates and transforms disability and care. Twenty-two people with acquired brain injury and their main informal caregivers (n = 44) were video-recorded filling in the disability claim form. Participants disagreed on 26% of the questions, revealing two types of problems. Translation problems arose as participants struggled to provide categorical responses to ambiguous questions and were unable to report contextual variability in care needs or divergences of perception. Transformation problems arose as participants resisted the way in which the form positioned them, forcing them to conceptualize their relationship in terms of dependency and burden. The disability claim form co-opts claimants to translate care and disability into bureaucratically predefined categories, and it transforms the care relationship that it purports to document. PMID:25792487
KSI's Cross Insulated Core Transformer Technology
Uhmeyer, Uwe
2009-08-04
Cross Insulated Core Transformer (CCT) technology improves on Insulated Core Transformer (ICT) implementations. ICT systems are widely used in very high voltage, high power, power supply systems. In an ICT transformer ferrite core sections are insulated from their neighboring ferrite cores. Flux leakage is present at each of these insulated gaps. The flux loss is raised to the power of stages in the ICT design causing output voltage efficiency to taper off with increasing stages. KSI's CCT technology utilizes a patented technique to compensate the flux loss at each stage of an ICT system. Design equations to calculate the flux compensation capacitor value are presented. CCT provides corona free operation of the HV stack. KSI's CCT based High Voltage power supply systems offer high efficiency operation, high frequency switching, low stored energy and smaller size over comparable ICT systems.
Visualizing the electrocardiogram through orbital transform.
Illanes-Manriquez, Alfredo; Jiménez, Raúl; Dinamarca, Gustavo; Jiménez, Claudia; Lecannelier, Eduardo
2010-01-01
The purpose of this work is to present a new electrocardiogram (ECG) visualization technique through a mathematical transform applied to one lead ECG signal. This transform, called orbital transform (OT) in this work, consists of a remapping of the ECG signal to a spatial curve represented by a three dimensional phase portrait. With this spatial curve it is possible to observe the evolution of changes in the QRS complex, which are not always clear to distinguish by a simple visual inspection of the temporal ECG signal. Moreover, using the projection of this curve in one of the 2D planes it is possible to easily calculate variation ranges of several ECG parameters such as maximal and minimal waves amplitudes and maximal and minimal wave slopes.
NASA Astrophysics Data System (ADS)
Fustich, C. D.
1980-03-01
A series of transformer room fire tests are reported to demonstate the shock hazard present when automatic sprinklers operate over energized electrical equipment. Fire protection was provided by standard 0.5 inch pendent automatic sprinklers temperature rated at 135 F and installed to give approximately 150 sq ft per head coverage. A 480 v dry transformer was used in the room to provide a three phase, four wire distribution system. It is shown that the induced currents in the test room during the various tests are relatively small and pose no appreciable personnel shock hazard.
Earth Limb Radiance Transformation.
1981-03-02
AD-A097 523 AEROSPACE CORP EL SEGUNDO CA CHEMISTRY AND PHYSICS LAB F/G 4/1 EARTH LIMB RADIANCE TRANSFORMATION (U) MAR AI S 4 YOUNG F0701-80 -C-0081... Earth Limb Radiance Trafisformation Prepared by S. J. YOUNG Chemistr and Physics Laboratory Laboratory Operations The Aerospace Corporation S.El...ITLEK (and Subtitle) TYPE OF REPORT & P53100 COVERED Earth Limb Radiance Transformation. ( Interim ./ / /TR-OJ081(697j7-g4)-l-- i7.Step hen J. Young
Genetic Transformation of Switchgrass
NASA Astrophysics Data System (ADS)
Xi, Yajun; Ge, Yaxin; Wang, Zeng-Yu
Switchgrass (Panicum virgatum L.) is a highly productive warm-season C4 species that is being developed into a dedicated biofuel crop. This chapter describes a protocol that allows the generation of transgenic switchgrass plants by Agrobacterium tumefaciens-mediated transformation. Embryogenic calluses induced from caryopses or inflorescences were used as explants for inoculation with A. tumefaciens strain EHA105. Hygromycin phosphotransferase gene (hph) was used as the selectable marker and hygromycin was used as the selection agent. Calluses resistant to hygromycin were obtained after 5-6 weeks of selection. Soil-grown switchgrass plants were regenerated about 6 months after callus induction and Agrobacterium-mediated transformation.
Bykowski, Tomasz; Stevenson, Brian
2008-11-01
This chapter describes common laboratory procedures that can reduce the risk of culture contaminations (sepsis), collectively referred as "aseptic technique." Two major strategies of aseptic work are described: using a Bunsen burner and a laminar flow hood. Both methods are presented in the form of general protocols applicable to a variety of laboratory tasks such as pipetting and dispensing aliquots, preparing growth media, and inoculating, passaging, and spreading microorganisms on petri dishes.
Chen, Gang; Lin, Yuehe
2008-07-20
Sensitive and selective detection techniques are of crucial importance for capillary electrophoresis (CE), microfluidic chips, and other microfluidic systems. Electrochemical detectors have attracted considerable interest for microfluidic systems with features that include high sensitivity, inherent miniaturization of both the detection and control instrumentation, low cost and power demands, and high compatibility with microfabrication technology. The commonly used electrochemical detectors can be classified into three general modes: conductimetry, potentiometry, and amperometry.
Psychophysical rating of image compression techniques
NASA Technical Reports Server (NTRS)
Stein, Charles S.; Hitchner, Lewis E.; Watson, Andrew B.
1989-01-01
Image compression schemes abound with little work which compares their bit-rate performance based on subjective fidelity measures. Statistical measures of image fidelity, such as squared error measures, do not necessarily correspond to subjective measures of image fidelity. Most previous comparisons of compression techniques have been based on these statistical measures. A psychophysical method has been used to estimate, for a number of compression techniques, a threshold bit-rate yielding a criterion level of performance in discriminating original and compressed images. The compression techniques studied include block truncation, Laplacian pyramid, block discrete cosine transform, with and without a human visual system scaling, and cortex transform coders.
Video coding using Karhunen-Loeve transform and motion compensation
NASA Astrophysics Data System (ADS)
Musatenko, Yurij S.; Soloveyko, Olexandr M.; Kurashov, Vitalij N.; Dubikovskiy, Vladislav A.
1999-07-01
The paper present a new method for video compression. The discussed techniques consider video frames as a set of correlated images. Common approach to the problem of compression of correlated images is to use some orthogonal transform, for example cosine or wavelet transform, in order to remove the correlation among images and then to compress resolution coefficients using already known compression technique such as JPEG or EZW. However, the most optimal representation for removing of correlation among images is Karhunen-Loeve (KL) transform. In the paper we apply recently proposed Optimal Image Coding using KL transform method (OICKL) based on this approach. In order to take into account the nature of video we use Triangle Motion Compensation to improve correlation among frames. Experimental part compares the performance of plain OICKL codec with OICKL and motion compensation combined. Recommendations concerning using of motion compensation with OICKL technique are worked out.
Coarsening strategies for unstructured multigrid techniques with application to anisotropic problems
NASA Technical Reports Server (NTRS)
Morano, E.; Mavriplis, D. J.; Venkatakrishnan, V.
1995-01-01
Over the years, multigrid has been demonstrated as an efficient technique for solving inviscid flow problems. However, for viscous flows, convergence rates often degrade. This is generally due to the required use of stretched meshes (i.e., the aspect-ratio AR = delta y/delta x is much less than 1) in order to capture the boundary layer near the body. Usual techniques for generating a sequence of grids that produce proper convergence rates on isotopic meshes are not adequate for stretched meshes. This work focuses on the solution of Laplace's equation, discretized through a Galerkin finite-element formulation on unstructured stretched triangular meshes. A coarsening strategy is proposed and results are discussed.
Coarsening Strategies for Unstructured Multigrid Techniques with Application to Anisotropic Problems
NASA Technical Reports Server (NTRS)
Morano, E.; Mavriplis, D. J.; Venkatakrishnan, V.
1996-01-01
Over the years, multigrid has been demonstrated as an efficient technique for solving inviscid flow problems. However, for viscous flows, convergence rates often degrade. This is generally due to the required use of stretched meshes (i.e. the aspect-ratio AR = (delta)y/(delta)x much less than 1) in order to capture the boundary layer near the body. Usual techniques for generating a sequence of grids that produce proper convergence rates on isotropic meshes are not adequate for stretched meshes. This work focuses on the solution of Laplace's equation, discretized through a Galerkin finite-element formulation on unstructured stretched triangular meshes. A coarsening strategy is proposed and results are discussed.
Transformation Laplacian metamaterials: recent advances in manipulating thermal and dc fields
NASA Astrophysics Data System (ADS)
Han, Tiancheng; Qiu, Cheng-Wei
2016-04-01
The full control of single or even multiple physical fields has attracted intensive research attention in the past decade, thanks to the development of metamaterials and transformation optics. Significant progress has been made in vector fields (e.g., optics, electromagnetics, and acoustics), leading to a host of strikingly functional metamaterials, such as invisibility cloaks, illusion devices, concentrators, and rotators. However, metamaterials in vector fields, designed through coordinate transformation of Maxwell’s equations, usually require extreme parameters and impose challenges on the actual realization. In this context, metamaterials in scalar fields (e.g., thermal and dc fields), which are mostly governed by the Laplace equation, lead to more plausible and facile implementations, since there are native insulators and excellent conductors (serving as two extreme cases). This paper therefore is particularly dedicated to reviewing the most recent advances in Laplacian metamaterials in manipulating thermal (both transient and steady states) and dc fields, separately and (or) simultaneously. We focus on the theory, design, and realization of thermal/dc functional metamaterials that can be used to control heat flux and electric current at will. We also provide an outlook toward the challenges and future directions in this fascinating area.
Fixture for winding transformers
NASA Technical Reports Server (NTRS)
Mclyman, M. T.
1980-01-01
Bench-mounted fixture assists operator in winding toroid-shaped transformer cores. Toroid is rigidly held in place as wires are looped around. Arrangement frees both hands for rapid winding and untangling of wires that occurs when core is hand held.
NASA Technical Reports Server (NTRS)
Stoms, R. M.
1984-01-01
Numerically-controlled 5-axis machine tool uses transformer and meter to determine and indicate whether tool is in home position, but lacks built-in test mode to check them. Tester makes possible test, and repair of components at machine rather then replace them when operation seems suspect.
Computerized toroidal transformer design
NASA Technical Reports Server (NTRS)
1970-01-01
Computer program designs transformers which have one primary /center tap permissible/ and up to 20 untapped secondaries, and which can handle up to 500 V across any one winding. Computer determines total secondary power, core type, primary turns, secondary turns, and wire sizes for primary and secondary windings.
Transformative Mixed Methods Research
ERIC Educational Resources Information Center
Mertens, Donna M.
2010-01-01
Paradigms serve as metaphysical frameworks that guide researchers in the identification and clarification of their beliefs with regard to ethics, reality, knowledge, and methodology. The transformative paradigm is explained and illustrated as a framework for researchers who place a priority on social justice and the furtherance of human rights.…
Education as Habitus Transformations
ERIC Educational Resources Information Center
von Rosenberg, Florian
2016-01-01
Unlike a conventional reading of Bourdieu, this article focuses on his work with regard to the transformation of social structure. In the context of a rereading, from an educational theory perspective, the article proposes an approach that allows for the linking of empirically informed social theory, on the one hand, and biography research…
Global Transformations and Agriculture.
ERIC Educational Resources Information Center
Campbell, Rex R.
1990-01-01
Examines worldwide political, economic, and social transformations and their impact on agriculture, focusing on biotechnology. Discusses rise of international corporations and accompanying constraints on government power. Sees trend toward increasing agribusiness role in world food and agricultural sectors. Calls for broader views and research in…
Improved Transformation of Anthurium
Technology Transfer Automated Retrieval System (TEKTRAN)
Methods to increase transformation efficiency and yields of transgenic Anthurium andraeanum Linden ex. André hybrids were sought while effecting gene transfer for resistance to the two most important pests, bacterial blight (Xanthomonas axonopodis pv. dieffenbachiae) and nematodes (Radopholus simili...
Fourier Transform Mass Spectrometry.
ERIC Educational Resources Information Center
Gross, Michael L.; Rempel, Don L.
1984-01-01
Discusses the nature of Fourier transform mass spectrometry and its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. Examines its operation, capabilities and limitations, applications (ion storage, ion manipulation, ion chemistry), and future applications and developments. (JN)
Winthrop College Transformed Curriculum.
ERIC Educational Resources Information Center
Hawisher, Margaret F.
Dealing with the issue of a changing society and recognizing that teacher education has remained basically unchanged for 100 years, the faculty of the Winthrop College School of Education agreed to take the risk involved with transforming the teacher education curriculum. Three interdisciplinary teams have identified curriculum to be taught to…
Transformative Change Initiative
ERIC Educational Resources Information Center
Bragg, D. D.; Kirby, C.; Witt, M. A.; Richie, D.; Mix, S.; Feldbaum, M.; Liu, S.; Mason, M.
2014-01-01
The Transformative Change Initiative (TCI) is dedicated to assisting community colleges to scale up innovation in the form of guided pathways, programs of study, and evidence-based strategies to improve student outcomes and program, organization, and system performance. The impetus for TCI is the Trade Adjustment Assistance Community College and…
Transformable descent vehicles
NASA Astrophysics Data System (ADS)
Pichkhadze, K. M.; Finchenko, V. S.; Aleksashkin, S. N.; Ostreshko, B. A.
2016-12-01
This article presents some types of planetary descent vehicles, the shape of which varies in different flight phases. The advantages of such vehicles over those with unchangeable form (from launch to landing) are discussed. It is shown that the use of transformable descent vehicles widens the scope of possible tasks to solve.
Transformer Impedance Reflection Demonstration
ERIC Educational Resources Information Center
Layton, William
2014-01-01
Questions often arise as to how a device attached to a transformer can draw power from the electrical power grid since it seems that the primary and secondary are not connected to one another. However, a closer look at how the primary and secondary are linked together magnetically and a consideration of the role of Lenz's law in this linkage…
Transformation: A Selected Bibliography
2007-04-30
Transforming the Institutional Army: Changing the Engine of Change. Strategy Research Project. Carlisle Barracks, PA: U.S. Army War College, 2003...1.0. Washington, D.C.: U.S. Department of Defense, 2005. 76pp. (U260 . J85 2005) http://www.dtic.mil/futurejointwarfare/concepts/c2_jic.pdf U.S