Photonic band structures solved by a plane-wave-based transfer-matrix method.
Li, Zhi-Yuan; Lin, Lan-Lan
2003-04-01
Transfer-matrix methods adopting a plane-wave basis have been routinely used to calculate the scattering of electromagnetic waves by general multilayer gratings and photonic crystal slabs. In this paper we show that this technique, when combined with Bloch's theorem, can be extended to solve the photonic band structure for 2D and 3D photonic crystal structures. Three different eigensolution schemes to solve the traditional band diagrams along high-symmetry lines in the first Brillouin zone of the crystal are discussed. Optimal rules for the Fourier expansion over the dielectric function and electromagnetic fields with discontinuities occurring at the boundary of different material domains have been employed to accelerate the convergence of numerical computation. Application of this method to an important class of 3D layer-by-layer photonic crystals reveals the superior convergency of this different approach over the conventional plane-wave expansion method.
The Riccati transfer matrix method. [for computerized structural analysis
NASA Technical Reports Server (NTRS)
Horner, G. C.; Pilkey, W. D.
1977-01-01
The Riccati transfer matrix method is a new technique for analyzing structural members. This new technique makes use of an existing large catalog of transfer matrices for various structural members such as rotating shafts. The numerical instability encountered when calculating high resonant frequencies, static response of a flexible member on a stiff foundation, or the response of a long member by the transfer matrix method is eliminated by the Riccati transfer matrix method. The computational time and storage requirements of the Riccati transfer matrix method are about half the values for the transfer matrix method. A rotating shaft analysis demonstrates the numerical accuracy of the method.
Comparison between parallel transfer matrix method and admittance sum method.
Verdière, Kévin; Panneton, Raymond; Elkoun, Saïd; Dupont, Thomas; Leclaire, Philippe
2014-08-01
A transfer matrix method to predict absorption coefficient and transmission loss of parallel assemblies of materials which can be expressed by a 2 × 2 transfer matrix was published recently. However, the usual method based on the sum of admittances is largely used to predict also surface admittance of parallel assemblies. This paper aims to highlight differences between both methods through three examples on a parallel assembly backed by (1) a rigid wall, (2) an air cavity, and (3) an anechoic termination.
Modified transfer matrix method for asymmetric rotor-bearing systems
NASA Astrophysics Data System (ADS)
Kang, Yuan; Lee, An-Chen; Shih, Yuan-Pin
1994-07-01
A modified transfer matrix method (MTMM) is developed to analyze rotor-bearing systems with an asymmetric shaft and asymmetric disks. The rotating shaft is modeled by a Rayleigh-Euler beam considering the effects of the rotary inertia and gyroscopic moments. Specifically, a transfer matrix of the asymmetric shaft segments is derived in a continuous-system sense to give accurate solutions. The harmonic balance method is incorporated in the transfer matrix equations, so that steady-state responses of synchronous and superharmonic whirls can be determined. A numerical example is presented to demonstrate the effectiveness of this approach.
Hybrid transfer-matrix FDTD method for layered periodic structures.
Deinega, Alexei; Belousov, Sergei; Valuev, Ilya
2009-03-15
A hybrid transfer-matrix finite-difference time-domain (FDTD) method is proposed for modeling the optical properties of finite-width planar periodic structures. This method can also be applied for calculation of the photonic bands in infinite photonic crystals. We describe the procedure of evaluating the transfer-matrix elements by a special numerical FDTD simulation. The accuracy of the new method is tested by comparing computed transmission spectra of a 32-layered photonic crystal composed of spherical or ellipsoidal scatterers with the results of direct FDTD and layer-multiple-scattering calculations.
Improved transfer matrix methods for calculating quantum transmission coefficient.
Biswas, Debabrata; Kumar, Vishal
2014-07-01
Methods for calculating the transmission coefficient are proposed, all of which arise from improved nonreflecting WKB boundary conditions at the edge of the computational domain in one-dimensional geometries. In the first, the Schrödinger equation is solved numerically, while the second is a transfer matrix (TM) algorithm where the potential is approximated by steps, but with the first and last matrix modified to reflect the new boundary condition. Both methods give excellent results with first-order WKB boundary conditions. The third uses the transfer matrix method with third-order WKB boundary conditions. For the parabolic potential, the average error for the modified third-order TM method reduces by factor of 4100 over the unmodified TM method.
Transfer matrix method and dispersive formula of light in thin films
NASA Astrophysics Data System (ADS)
Dai, Hong-xia; Liu, Qi-neng
2009-05-01
Using boundary conditions of electromagnetic waves , a new transfer matrix method that study electromagnetic waves in thin films and a dispersive formula of 1D photonic crystal are derived. Using the formula reflection and refraction of light is studied, the forbidden band of 1D photonic crystal is studied. The transfer matrix method and the classic characteristic matrix method are compared. The transfer matrix method can not only solve the problem that characteristic matrix method can solve, the transfer matrix method can also solve the problem that characteristic matrix method can not solve. Therefore the transfer matrix method is a more fundamental and wider range of application.
Selective spin transport through a quantum heterostructure: Transfer matrix method
NASA Astrophysics Data System (ADS)
Dey, Moumita; Maiti, Santanu K.
2016-09-01
In the present work, we propose that a one-dimensional quantum heterostructure composed of magnetic and non-magnetic (NM) atomic sites can be utilized as a spin filter for a wide range of applied bias voltage. A simple tight-binding framework is given to describe the conducting junction where the heterostructure is coupled to two semi-infinite one-dimensional NM electrodes. Based on transfer matrix method, all the calculations are performed numerically which describe two-terminal spin-dependent transmission probability along with junction current through the wire. Our detailed analysis may provide fundamental aspects of selective spin transport phenomena in one-dimensional heterostructures at nanoscale level.
Transfer matrix method for multibody systems for piezoelectric stack actuators
NASA Astrophysics Data System (ADS)
Zhu, Wei; Chen, Gangli; Bian, Leixiang; Rui, Xiaoting
2014-09-01
In order to achieve a large displacement output from a piezoelectric actuator, we realized the piezoelectric stack actuator (PSA) by mechanically layering/stacking multi-chip piezoelectric wafers in a series and electrically connecting the electrodes in parallel. In this paper, in order to accurately model the hysteresis and the dynamic characteristics of a PSA, the transfer matrix method for multibody systems (MSTMM) was adopted to describe the dynamic characteristics, and the Bouc-Wen hysteresis operator was used to represent the hysteresis. The vibration characteristics of a PSA and a piezo-actuated positioning mechanism (PPM) are derived and analyzed by the MSTMM; then, the dynamic responses of the PSA and the PPM are calculated. The experimental results show that the new method can accurately portray the hysteresis and the dynamic characteristics of a PSA and a PPM. On one hand, if we use this method to model the dynamic response of the PSA and the PPM, the PSA can be considered as a flexible body, as opposed to a mass-spring-damper system, which is in better agreement with the actual condition. On the other hand, the global dynamics equation is not needed for the study of system dynamics, and the dynamics equation has a small-sized matrix and a higher computational speed. Therefore, this method gives a broad range of possibilities for model-based controller design.
Vibration analysis of pipelines with arbitrary branches by absorbing transfer matrix method
NASA Astrophysics Data System (ADS)
Liu, Gongmin; Li, Shuaijun; Li, Yanhua; Chen, Hao
2013-11-01
Branched pipes of arbitrary shapes are prevalent in pipe systems. Considering fluid-structure interaction (FSI), an absorbing transfer matrix method in frequency domain for fluid-filled pipelines with any branched pipes is proposed in this paper. A dominant chain of pipeline would be selected, and the point transfer matrix of each junction on the dominant chain would be determined. Here, the point transfer matrix, representing the influence of branched pipes at the junction on the dominant pipeline, was "absorbed" by the dominant chain. Based on these, with transfer matrixes of other elements, the fluid and structure dynamics problem could be solved following the chain transfer matrix method process. Several numerical examples with different constraints are presented to illustrate the application of the proposed method. Moreover, the experiment of cross-shaped pipes with various boundary conditions was carried out. And results from the present approach were validated by measured and numerical data. Then, the forced vibrations of branched pipes were analyzed by considering the effects of various parameters, which shows the fluid pressure and vibrations can be optimized by changing the branch angles and positions. Through these examples, it is shown that the proposed method is efficient and can be used to calculate branched pipes of any shape.
A Synthetic Approach to the Transfer Matrix Method in Classical and Quantum Physics
ERIC Educational Resources Information Center
Pujol, O.; Perez, J. P.
2007-01-01
The aim of this paper is to propose a synthetic approach to the transfer matrix method in classical and quantum physics. This method is an efficient tool to deal with complicated physical systems of practical importance in geometrical light or charged particle optics, classical electronics, mechanics, electromagnetics and quantum physics. Teaching…
Free vibration characteristics of multiple load path blades by the transfer matrix method
NASA Technical Reports Server (NTRS)
Murthy, V. R.; Joshi, Arun M.
1986-01-01
The determination of free vibrational characteristics is basic to any dynamic design, and these characteristics can form the basis for aeroelastic stability analyses. Conventional helicopter blades are typically idealized as single-load-path blades, and the transfer matrix method is well suited to analyze such blades. Several current helicopter dynamic programs employ transfer matrices to analyze the rotor blades. In this paper, however, the transfer matrix method is extended to treat multiple-load-path blades, without resorting to an equivalent single-load-path approximation. With such an extension, these current rotor dynamic programs which employ the transfer matrix method can be modified with relative ease to account for the multiple load paths. Unlike the conventional blades, the multiple-load-path blades require the introduction of the axial degree-of-freedom into the solution process to account for the differential axial displacements of the different load paths. The transfer matrix formulation is validated through comparison with the finite-element solutions.
Modeling of wave propagation in drill strings using vibration transfer matrix methods.
Han, Je-Heon; Kim, Yong-Joe; Karkoub, Mansour
2013-09-01
In order to understand critical vibration of a drill bit such as stick-slip and bit-bounce and their wave propagation characteristics through a drill string system, it is critical to model the torsional, longitudinal, and flexural waves generated by the drill bit vibration. Here, a modeling method based on a vibration transfer matrix between two sets of structural wave variables at the ends of a constant cross-sectional, hollow, circular pipe is proposed. For a drill string system with multiple pipe sections, the total vibration transfer matrix is calculated by multiplying all individual matrices, each is obtained for an individual pipe section. Since drill string systems are typically extremely long, conventional numerical analysis methods such as a finite element method (FEM) require a large number of meshes, which makes it computationally inefficient to analyze these drill string systems numerically. The proposed "analytical" vibration transfer matrix method requires significantly low computational resources. For the validation of the proposed method, experimental and numerical data are obtained from laboratory experiments and FEM analyses conducted by using a commercial FEM package, ANSYS. It is shown that the modeling results obtained by using the proposed method are well matched with the experimental and numerical results. PMID:23967925
Modeling of wave propagation in drill strings using vibration transfer matrix methods.
Han, Je-Heon; Kim, Yong-Joe; Karkoub, Mansour
2013-09-01
In order to understand critical vibration of a drill bit such as stick-slip and bit-bounce and their wave propagation characteristics through a drill string system, it is critical to model the torsional, longitudinal, and flexural waves generated by the drill bit vibration. Here, a modeling method based on a vibration transfer matrix between two sets of structural wave variables at the ends of a constant cross-sectional, hollow, circular pipe is proposed. For a drill string system with multiple pipe sections, the total vibration transfer matrix is calculated by multiplying all individual matrices, each is obtained for an individual pipe section. Since drill string systems are typically extremely long, conventional numerical analysis methods such as a finite element method (FEM) require a large number of meshes, which makes it computationally inefficient to analyze these drill string systems numerically. The proposed "analytical" vibration transfer matrix method requires significantly low computational resources. For the validation of the proposed method, experimental and numerical data are obtained from laboratory experiments and FEM analyses conducted by using a commercial FEM package, ANSYS. It is shown that the modeling results obtained by using the proposed method are well matched with the experimental and numerical results.
NASA Astrophysics Data System (ADS)
Hongyun, Xie; Liang, Chen; Pei, Shen; Botao, Sun; Renqing, Wang; Ying, Xiao; Yunxia, You; Wanrong, Zhang
2010-06-01
A novel cascaded DFB laser, which consists of two serial gratings to provide selectable wavelengths, is presented and analyzed by the transfer matrix method. In this method, efficient facet reflectivity is derived from the transfer matrix built for each serial section and is then used to simulate the performance of the novel cascaded DFB laser through self-consistently solving the gain equation, the coupled wave equation and the current continuity equations. The simulations prove the feasibility of this kind of wavelength selectable laser and a corresponding designed device with two selectable wavelengths of 1.51 μm and 1.53 μm is realized by experiments on InP-based multiple quantum well structure.
Transfer matrix method applied to the parallel assembly of sound absorbing materials.
Verdière, Kévin; Panneton, Raymond; Elkoun, Saïd; Dupont, Thomas; Leclaire, Philippe
2013-12-01
The transfer matrix method (TMM) is used conventionally to predict the acoustic properties of laterally infinite homogeneous layers assembled in series to form a multilayer. In this work, a parallel assembly process of transfer matrices is used to model heterogeneous materials such as patchworks, acoustic mosaics, or a collection of acoustic elements in parallel. In this method, it is assumed that each parallel element can be modeled by a 2 × 2 transfer matrix, and no diffusion exists between elements. The resulting transfer matrix of the parallel assembly is also a 2 × 2 matrix that can be assembled in series with the classical TMM. The method is validated by comparison with finite element (FE) simulations and acoustical tube measurements on different parallel/series configurations at normal and oblique incidence. The comparisons are in terms of sound absorption coefficient and transmission loss on experimental and simulated data and published data, notably published data on a parallel array of resonators. From these comparisons, the limitations of the method are discussed. Finally, applications to three-dimensional geometries are studied, where the geometries are discretized as in a FE concept. Compared to FE simulations, the extended TMM yields similar results with a trivial computation time.
Biorthonormal transfer-matrix renormalization-group method for non-Hermitian matrices.
Huang, Yu-Kun
2011-03-01
A biorthonormal transfer-matrix renormalization-group (BTMRG) method for non-Hermitian matrices is presented. This BTMRG produces a dual set of biorthonormal bases to construct the renormalized transfer matrix with only half the dimensions of the matrix of a conventional transfer-matrix renormalization group (TMRG). We show that under generic conditions, such biorthonormal bases always exist. Based on a special E·S·E scheme (where S and E represent the system and environment blocks, respectively, and the two dots in between represent two additional physical sites), the BTMRG method can achieve zero truncation of any reduced state in describing both current left and right Perron states so as to reach a high degree of efficiency and accuracy. We believe that the BTMRG constitutes a more powerful and robust tool than conventional TMRG for non-Hermitian matrices and that it would allow us to better understand the collective behaviors and emerging phenomena of strongly correlated many-body systems. We also show that this scheme is particularly adapted to the calculation of the two-site correlation function of a one-dimensional quantum or two-dimensional classical lattice model.
NASA Astrophysics Data System (ADS)
Kamal, Ayman; Giurgiutiu, Victor
2014-03-01
This paper discusses combined transfer matrix method (TMM) with stiffness matrix method (SMM) for obtaining a stable solution for dispersion curves of Lamb wave propagation in non-isotropic layers. TMM developed by Thomson and Haskell experiences numerical deficiency at high frequency thickness simulations. SMM was proposed by different researchers to solve the instability issue of TMM. This study shows that stable SMM is good at high frequencies, and TMM needs to be combined with SMM to obtain stable and robust behavior over the frequency range. Numerical simulations of dispersion curves are presented for wave propagation in orthotropic unidirectional fiber composites and cross ply composites. The paper ends with conclusions and future work.
Transfer matrix method-based approach to study the bi-gyrotropic magnetic materials
NASA Astrophysics Data System (ADS)
Zamani, Mehdi; Hajesmaeili, Hamidreza Nezhad; Zandi, Mohammad Hossein
2016-08-01
Optical and magneto-optical (MO) responses in magnetic multilayer systems are calculated by transfer matrix method (TMM). In a bi-gyrotropic medium, electric permittivity (ε) and magnetic permeability (μ) coefficients are in the form of non-diagonal tensors, synchronously, which their non-diagonal elements refer to the existence of anisotropy in such medium. In the present study, in addition to present a TMM based-approach for bi-gyrotropic medium, numerical simulations for studying the amount of optical and MO parameters of the bi-gyrotropic Yttrium Iron Garnet (YIG) material, in both transmission and reflection configurations, have been done.
Optimization on microlattice materials for sound absorption by an integrated transfer matrix method.
Cai, Xiaobing; Yang, Jun; Hu, Gengkai
2015-04-01
Materials with well-defined microlattice structures are superlight, stable, and thus bear great potential in sound absorption. An integrated transfer matrix method (TMM) is proposed to evaluate the sound absorbing efficiency of these lattice materials, in which a massive number of micropores are densely placed. A comparison between integrated TMM and conventional TMM reveals that the proposed approach offers better predictions on sound absorption of microlattice. This approach is then employed to optimize the microlattice material to determine the best pore and porosity that lead to maximum absorbing efficiency capability and minimum required thickness to attain a target sound absorption. PMID:25920886
Optimization on microlattice materials for sound absorption by an integrated transfer matrix method.
Cai, Xiaobing; Yang, Jun; Hu, Gengkai
2015-04-01
Materials with well-defined microlattice structures are superlight, stable, and thus bear great potential in sound absorption. An integrated transfer matrix method (TMM) is proposed to evaluate the sound absorbing efficiency of these lattice materials, in which a massive number of micropores are densely placed. A comparison between integrated TMM and conventional TMM reveals that the proposed approach offers better predictions on sound absorption of microlattice. This approach is then employed to optimize the microlattice material to determine the best pore and porosity that lead to maximum absorbing efficiency capability and minimum required thickness to attain a target sound absorption.
NASA Astrophysics Data System (ADS)
Rui, Xiao-Ting; Kreuzer, Edwin; Rong, Bao; He, Bin
2012-04-01
In this paper, by defining new state vectors and developing new transfer matrices of various elements moving in space, the discrete time transfer matrix method of multi-rigid-flexible-body system is expanded to study the dynamics of multibody system with flexible beams moving in space. Formulations and numerical example of a rigid-flexible-body three pendulums system moving in space are given to validate the method. Using the new method to study the dynamics of multi-rigid-flexible-body system moving in space, the global dynamics equations of system are not needed, the orders of involved matrices of the system are very low and the computational speed is high, irrespective of the size of the system. The new method is simple, straightforward, practical, and provides a powerful tool for multi-rigid-flexible-body system dynamics.
A revised version of the transfer matrix method to analyze one-dimensional structures
NASA Technical Reports Server (NTRS)
Nitzsche, F.
1983-01-01
A new and general method to analyze both free and forced vibration characteristics of one-dimensional structures is discussed in this paper. This scheme links for the first time the classical transfer matrix method with the recently developed integrating matrix technique to integrate systems of differential equations. Two alternative approaches to the problem are presented. The first is based upon the lumped parameter model to account for the inertia properties of the structure. The second releases that constraint allowing a more precise description of the physical system. The free vibration of a straight uniform beam under different support conditions is analyzed to test the accuracy of the two models. Finally some results for the free vibration of a 12th order system representing a curved, rotating beam prove that the present method is conveniently extended to more complicated structural dynamics problems.
Transfer-matrix-based method for an analytical description of velocity-map-imaging spectrometers
NASA Astrophysics Data System (ADS)
Harb, M. M.; Cohen, S.; Papalazarou, E.; Lépine, F.; Bordas, C.
2010-12-01
We propose a simple and general analytical model describing the operation of a velocity-map-imaging spectrometer. We show that such a spectrometer, possibly equipped with a magnifying lens, can be efficiently modeled by combining analytical expressions for the axial potential distributions along with a transfer matrix method. The model leads transparently to the prediction of the instrument's operating conditions as well as to its resolution. A photoelectron velocity-map-imaging spectrometer with a magnifying lens, built and operated along the lines suggested by the model has been successfully employed for recording images at threshold photoionization of atomic lithium. The model's reliability is demonstrated by the fairly good agreement between experimental results and calculations. Finally, the limitations of the analytical method along with possible generalizations, extensions, and potential applications are also discussed. The model may serve as a guide for users interested in building and operating such spectrometers as well as a tutorial tool.
Analysis of surface modes in photonic crystals by a plane-wave transfer-matrix method.
Che, Ming; Li, Zhi-Yuan
2008-09-01
We have developed a plane-wave transfer-matrix method (PWTMM) with the aid of the interpolation technique to analyze the dispersion relation of surface modes in photonic crystal or photonic crystal surface waveguide. The proposed approach has been applied to several surface structures in two-dimensional photonic crystals. The calculated dispersion relation of the surface modes is in good agreement with the result obtained by the conventional plane-wave expansion method in combination with the supercell technique. The developed PWTMM needs to handle only a single unit-cell layer domain and is therefore numerically friendly. The proposed approach can become an efficient and accurate numerical tool to understand and design surface modes in different two-dimensional and three-dimensional photonic crystals with complex geometries.
NASA Astrophysics Data System (ADS)
Jun, Oh-Sung; Kim, Paul Y.
1994-02-01
The influence coefficients for undamped flexible rotors are analytically derived and then compared and discussed for various damping coefficients. The concept of the transfer matrix method is partially adapted in the formulation. Single-disk and single cylinder rotor models are used for one- and two-plane balancing models, respectively. The gyroscopic effect of the disk or cylinder, which has been included in the formulation, is proved important through a simplified example rotor model. Taking the gyroscopic effect into account when calculating the influence coefficient is especially important near the resonant and antiresonant frequencies of the rotor. The simplified model also shows that an increase in damping reduces the sharpness of magnitude curve of influence coefficients and smoothens the change of phase at around the resonant and antiresonant frequencies.
Thermodynamic properties of mixed-spin chains in magnetic field by the transfer matrix method
NASA Astrophysics Data System (ADS)
Fu, H. H.; Yao, K. L.; Liu, Z. L.
2006-10-01
Motivated by recent experimental synthesis of molecule-based ferrimagnetics, we have investigated the thermodynamic properties of one-dimensional antiferromagnetic-ferromagnetic mixed spin- {1}/{2} lozenge chain in external magnetic fields at low temperature, using the transfer matrix method. The magnetization and the specific heat of the spin system have been evaluated numerically from the free energy. The magnetization as a function of the magnetic field at low temperature shows step-like plateau characterized by three critical magnetic fields, which reflects the competing effect of magnetic interactions and thermal fluctuations. The double-peak structure in the curves of the specific heat is also found, which comes from the huge variation of the long-range order parameters. Our results show that the thermodynamic properties of the mixed spin- {1}/{2} molecule-based ferrimagnetics are very analogous to the behaviors of the spin-1 and spin- {1}/{2} mixed antiferromagentic chain.
Discrete time transfer matrix method for dynamics of multibody system with real-time control
NASA Astrophysics Data System (ADS)
Rong, Bao; Rui, Xiaoting; Wang, Guoping; Yang, Fufeng
2010-03-01
By taking the control and feedback parameters into account in state vectors, defining new state vectors and deducing new transfer equations and transfer matrices for actuator, controlled element and feedback element, a new method named as the discrete time transfer matrix method for controlled multibody system (CMS) is developed to study dynamics of CMS with real-time control in this paper. This method does not need the global dynamics equations of system. It has the modeling flexibility, low order of system matrix, high computational efficiency, and is efficient for general CMS. Compared with the ordinary dynamics methods, the proposed method has more advantages for dynamics design and real-time control of a complex CMS. Adopting the PID adaptive controller and modal velocity feedback control on PZT actuators, and applying the proposed method and ordinary dynamics method, respectively, the tip trajectory tracking for a flexible manipulator is carried out. Formulations of the method as well as numerical simulation are given to validate the proposed method.
Kim, Euitae; Shidahara, Miho; Tsoumpas, Charalampos; McGinnity, Colm J; Kwon, Jun Soo; Howes, Oliver D; Turkheimer, Federico E
2013-06-01
We validated the use of a novel image-based method for partial volume correction (PVC), structural-functional synergistic resolution recovery (SFS-RR) for the accurate quantification of dopamine synthesis capacity measured using [(18)F]DOPA positron emission tomography. The bias and reliability of SFS-RR were compared with the geometric transfer matrix (GTM) method. Both methodologies were applied to the parametric maps of [(18)F]DOPA utilization rates (ki(cer)). Validation was first performed by measuring repeatability on test-retest scans. The precision of the methodologies instead was quantified using simulated [(18)F]DOPA images. The sensitivity to the misspecification of the full-width-half-maximum (FWHM) of the scanner point-spread-function on both approaches was also assessed. In the in-vivo data, the ki(cer) was significantly increased by application of both PVC procedures while the reliability remained high (intraclass correlation coefficients >0.85). The variability was not significantly affected by either PVC approach (<10% variability in both cases). The corrected ki(cer) was significantly influenced by the FWHM applied in both the acquired and simulated data. This study shows that SFS-RR can effectively correct for partial volume effects to a comparable degree to GTM but with the added advantage that it enables voxelwise analyses, and that the FWHM used can affect the PVC result indicating the importance of accurately calibrating the FWHM used in the recovery model.
NASA Astrophysics Data System (ADS)
Abbas, Laith K.; Zhou, Qinbo; Hendy, Hossam; Rui, Xiaoting
2015-08-01
The analysis of natural vibration characteristics has become one of important steps of the manufacture and dynamic design in the aerospace industry. This paper presents a new scenario called virtual cutting in the context of the transfer matrix method of linear multibody systems closed-loop topology for computing the free vibration characteristics of elastically coupled flexible launch vehicle boosters. In this approach, the coupled system is idealized as a triple-beam system-like structure coupled by linear translational springs, where a non-uniform free-free Euler-Bernoulli beam is used. A large thrust-to-weight ratio leads to large axial accelerations that result in an axial inertia load distribution from nose to tail. Consequently, it causes the development of significant compressive forces along the length of the launch vehicle. Therefore, it is important to take into account this effect in the transverse vibration model. This scenario does not need the global dynamics equations of a system, and it has high computational efficiency and low memory requirements. The validity of the presented scenario is achieved through comparison to other approaches published in the literature.
Allosteric conformational spread: Exact results using a simple transfer matrix method
NASA Astrophysics Data System (ADS)
Mochrie, S. G. J.; Mack, A. H.; Regan, L.
2010-09-01
A transfer matrix method is described for the conformational spread (CS) model of allosteric cooperativity within a one-dimensional arrangement of four-state binding sites. Each such binding site can realize one of two possible conformational states. Each of these states can either bind ligand or not bind ligand. Thus, analytical expressions that are exact within the context of the CS model are derived for the grand partition function, for the mean fraction of binding sites occupied by ligand versus ligand concentration, and for the mean fraction of binding sites in a given allosteric state versus ligand concentration. The utility of our analytical results is demonstrated by least-mean-square fitting of prior experimental results obtained on the bacterial flagellar motor for the fraction of FliM/FliG/FliN complexes with CheY-P bound [V. Sourjik and H. C. Berg, Proc. Natl. Acad. Sci. U.S.A. 99, 12669 (2002)10.1073/pnas.192463199] and for the cw bias [P. Cluzel , Science 287, 1652 (2000)10.1126/science.287.5458.1652], which plausibly may be identified as the fraction of protomers realizing state 2. Finally, the relationships between our analytical results and the classical Monod-Wyman-Changeaux, Koshland-Nemethy-Filmer, and McGhee-Von Hippel treatments of allosteric cooperativity are elucidated, as is the connection to an earlier approximate analytical treatment of the CS model.
Quantum propagation and confinement in 1D systems using the transfer-matrix method
NASA Astrophysics Data System (ADS)
Pujol, Olivier; Carles, Robert; Pérez, José-Philippe
2014-05-01
The aim of this article is to provide some Matlab scripts to the teaching community in quantum physics. The scripts are based on the transfer-matrix formalism and offer a very efficient and versatile tool to solve problems of a physical object (electron, proton, neutron, etc) with one-dimensional (1D) stationary potential energy. Resonant tunnelling through a multiple-barrier or confinement in wells of various shapes is particularly analysed. The results are quantitatively discussed with semiconductor heterostructures, harmonic and anharmonic molecular vibrations, or neutrons in a gravity field. Scripts and other examples (hydrogen-like ions and transmission by a smooth variation of potential energy) are available freely at http://www-loa.univ-lille1.fr/˜pujol in three languages: English, French and Spanish.
NASA Technical Reports Server (NTRS)
Shen, Ji-Yao; Taylor, Lawrence W., Jr.
1994-01-01
It is beneficial to use a distributed parameter model for large space structures because the approach minimizes the number of model parameters. Holzer's transfer matrix method provides a useful means to simplify and standardize the procedure for solving the system of partial differential equations. Any large space structures can be broken down into sub-structures with simple elastic and dynamical properties. For each single element, such as beam, tether, or rigid body, we can derive the corresponding transfer matrix. Combining these elements' matrices enables the solution of the global system equations. The characteristics equation can then be formed by satisfying the appropriate boundary conditions. Then natural frequencies and mode shapes can be determined by searching the roots of the characteristic equation at frequencies within the range of interest. This paper applies this methodology, and the maximum likelihood estimation method, to refine the modal characteristics of the NASA Mini-Mast Truss by successively matching the theoretical response to the test data of the truss. The method is being applied to more complex configurations.
NASA Technical Reports Server (NTRS)
Gray, Carl E., Jr.
1988-01-01
Using the Newtonian method, the equations of motion are developed for the coupled bending-torsion steady-state response of beams rotating at constant angular velocity in a fixed plane. The resulting equations are valid to first order strain-displacement relationships for a long beam with all other nonlinear terms retained. In addition, the equations are valid for beams with the mass centroidal axis offset (eccentric) from the elastic axis, nonuniform mass and section properties, and variable twist. The solution of these coupled, nonlinear, nonhomogeneous, differential equations is obtained by modifying a Hunter linear second-order transfer-matrix solution procedure to solve the nonlinear differential equations and programming the solution for a desk-top personal computer. The modified transfer-matrix method was verified by comparing the solution for a rotating beam with a geometric, nonlinear, finite-element computer code solution; and for a simple rotating beam problem, the modified method demonstrated a significant advantage over the finite-element solution in accuracy, ease of solution, and actual computer processing time required to effect a solution.
NASA Astrophysics Data System (ADS)
Gu, Zhiping
This paper extends Riccati transfer matrix method to the transient and stability analysis of large scale rotor-bearing systems with strong nonlinear elements, and proposes a mode summation-transfer matrix method, in which the field transfer matrix of a distributed mass uniform shaft segment is obtained with the aid of the idea of mode summation and Newmark beta formulation, and the Riccati transfer matrix method is adopted to stablize the boundary value problem of the nonlinear systems. In this investigation, the real nonlinearity of the strong nonlinear elements is considered, not linearized, and the advantages of the Riccati transfer matrix are retained. So, this method is especially applicable to analyze the transient response and stability of large-scale rotor-bear systems with strong nonlinear elements. One example, a single-spool rotating system with strong nonlinear elements, is given. The obtained results show that this method is superior to that of Gu and Chen (1990) in accuracy, stability, and economy.
Gurin, Péter; Varga, Szabolcs
2015-06-14
We extend the transfer matrix method of one-dimensional hard core fluids placed between confining walls for that case where the particles can pass each other and at most two layers can form. We derive an eigenvalue equation for a quasi-one-dimensional system of hard squares confined between two parallel walls, where the pore width is between σ and 3σ (σ is the side length of the square). The exact equation of state and the nearest neighbor distribution functions show three different structures: a fluid phase with one layer, a fluid phase with two layers, and a solid-like structure where the fluid layers are strongly correlated. The structural transition between differently ordered fluids develops continuously with increasing density, i.e., no thermodynamic phase transition occurs. The high density structure of the system consists of clusters with two layers which are broken with particles staying in the middle of the pore.
NASA Astrophysics Data System (ADS)
Gurin, Péter; Varga, Szabolcs
2015-06-01
We extend the transfer matrix method of one-dimensional hard core fluids placed between confining walls for that case where the particles can pass each other and at most two layers can form. We derive an eigenvalue equation for a quasi-one-dimensional system of hard squares confined between two parallel walls, where the pore width is between σ and 3σ (σ is the side length of the square). The exact equation of state and the nearest neighbor distribution functions show three different structures: a fluid phase with one layer, a fluid phase with two layers, and a solid-like structure where the fluid layers are strongly correlated. The structural transition between differently ordered fluids develops continuously with increasing density, i.e., no thermodynamic phase transition occurs. The high density structure of the system consists of clusters with two layers which are broken with particles staying in the middle of the pore.
Gurin, Péter; Varga, Szabolcs
2015-06-14
We extend the transfer matrix method of one-dimensional hard core fluids placed between confining walls for that case where the particles can pass each other and at most two layers can form. We derive an eigenvalue equation for a quasi-one-dimensional system of hard squares confined between two parallel walls, where the pore width is between σ and 3σ (σ is the side length of the square). The exact equation of state and the nearest neighbor distribution functions show three different structures: a fluid phase with one layer, a fluid phase with two layers, and a solid-like structure where the fluid layers are strongly correlated. The structural transition between differently ordered fluids develops continuously with increasing density, i.e., no thermodynamic phase transition occurs. The high density structure of the system consists of clusters with two layers which are broken with particles staying in the middle of the pore.
Anzaldo-Meneses, A.; Pereyra, P. . E-mail: ppereyra@correo.azc.uam.mx
2007-09-15
Based on the Sylvester and Frobenius theorems, we drastically enhance the feasibility of the transfer-matrix approach to deal with problems involving a large number of propagating and interfering modes, which require the solution of coupled differential equations and the evaluation of functions of matrix variables. We report closed formulas for the spectral decomposition of this type of functions. As specific example, besides the calculation of simple and well-known 1D one channel transfer matrices, we derive the multi-channel transfer matrix for an electron gas in the presence of a transverse electric field.
Hornišová, K; Billik, P
2014-01-01
Traditional technique of horn equation solved by transfer matrices as a model of vibration of ultrasonic systems consisting of sectional transducer, horn and load is discussed. Expression of vibration modes as a ratio of solutions of two Schrödinger equations gives better insight to the structure of a transfer matrix and properties of amplitudes of displacement and strain, and enables more systematic search for analytic solutions. Incorrectness of impedance matrix method and of equivalent circuit method on one hand and correctness and advantages of transfer matrix method in avoiding numerical artifacts and revealing the real features of the model on the other hand are demonstrated on examples. Discontinuous dependence of the nth resonant value on parameters of ultrasonic system, recently described in Sturm-Liouville theory, and consequently, a jump from half-wave to full-wave mode, is observed in a transducer model.
NASA Astrophysics Data System (ADS)
Pingbo, An; Li, Wang; Hongxi, Lu; Zhiguo, Yu; Lei, Liu; Xin, Xi; Lixia, Zhao; Junxi, Wang; Jinmin, Li
2016-06-01
The internal quantum efficiency (IQE) of the light-emitting diodes can be calculated by the ratio of the external quantum efficiency (EQE) and the light extraction efficiency (LEE). The EQE can be measured experimentally, but the LEE is difficult to calculate due to the complicated LED structures. In this work, a model was established to calculate the LEE by combining the transfer matrix formalism and an in-plane ray tracing method. With the calculated LEE, the IQE was determined and made a good agreement with that obtained by the ABC model and temperature-dependent photoluminescence method. The proposed method makes the determination of the IQE more practical and conventional. Project supported by the National Natural Science Foundation of China (Nos.11574306, 61334009), the China International Science and Technology Cooperation Program (No. 2014DFG62280), and the National High Technology Program of China (No. 2015AA03A101).
Bonfiglio, Paolo; Pompoli, Francesco; Lionti, Riccardo
2016-04-01
The transfer matrix method is a well-established prediction tool for the simulation of sound transmission loss and the sound absorption coefficient of flat multilayer systems. Much research has been dedicated to enhancing the accuracy of the method by introducing a finite size effect of the structure to be simulated. The aim of this paper is to present a reduced-order integral formulation to predict radiation efficiency and radiation impedance for a panel with equal lateral dimensions. The results are presented and discussed for different materials in terms of radiation efficiency, sound transmission loss, and the sound absorption coefficient. Finally, the application of the proposed methodology for rectangular multilayer systems is also investigated and validated against experimental data. PMID:27106325
Cozza, Dario; Ruiz, Carmen M; Duché, David; Giraldo, Sergio; Saucedo, Edgardo; Simon, Jean Jacques; Escoubas, Ludovic
2016-09-01
The fast and computationally inexpensive Modified Transfer Matrix Method (MTM) is employed to simulate the optical response of kesterite Cu_{2}ZnSnSe_{4} solar cells. This method can partially take into account the scattering effects due to roughness at the interfaces between the layers of the stack. We analyzed the optical behavior of the whole cell structure by varying the thickness of the TCO layer (iZnO + ITO) between 50 and 1200 nm and the buffer CdS layer between 0 and 100 nm. We propose optimal combinations of the TCO/CdS thicknesses that can locally maximize the device photocurrent. We provide experimental data that qualitatively confirm our theoretical predictions. PMID:27607723
Bonfiglio, Paolo; Pompoli, Francesco; Lionti, Riccardo
2016-04-01
The transfer matrix method is a well-established prediction tool for the simulation of sound transmission loss and the sound absorption coefficient of flat multilayer systems. Much research has been dedicated to enhancing the accuracy of the method by introducing a finite size effect of the structure to be simulated. The aim of this paper is to present a reduced-order integral formulation to predict radiation efficiency and radiation impedance for a panel with equal lateral dimensions. The results are presented and discussed for different materials in terms of radiation efficiency, sound transmission loss, and the sound absorption coefficient. Finally, the application of the proposed methodology for rectangular multilayer systems is also investigated and validated against experimental data.
Cozza, Dario; Ruiz, Carmen M; Duché, David; Giraldo, Sergio; Saucedo, Edgardo; Simon, Jean Jacques; Escoubas, Ludovic
2016-09-01
The fast and computationally inexpensive Modified Transfer Matrix Method (MTM) is employed to simulate the optical response of kesterite Cu_{2}ZnSnSe_{4} solar cells. This method can partially take into account the scattering effects due to roughness at the interfaces between the layers of the stack. We analyzed the optical behavior of the whole cell structure by varying the thickness of the TCO layer (iZnO + ITO) between 50 and 1200 nm and the buffer CdS layer between 0 and 100 nm. We propose optimal combinations of the TCO/CdS thicknesses that can locally maximize the device photocurrent. We provide experimental data that qualitatively confirm our theoretical predictions.
Gurin, Péter; Varga, Szabolcs
2013-12-28
The effect of confinement is studied on the local structure of two- and three-dimensional hard-core fluids. The hard disks are confined between two parallel lines, while the hard spheres are in a cylindrical hard pore. In both cases only nearest neighbour interactions are allowed between the particles. The vertical and longitudinal pair correlation functions are determined by means of the exact transfer-matrix method. The vertical pair correlation function indicates that the wall induced packing constraint gives rise to a zigzag (up-down sequence) shaped close packing structure in both two- and three-dimensional systems. The longitudinal pair correlation function shows that both systems transform continuously from a one-dimensional gas-like behaviour to a zigzag solid-like structure with increasing density.
Student Transfer Matrix, Fall 1996.
ERIC Educational Resources Information Center
Oklahoma State Regents for Higher Education, Oklahoma City.
The Student Transfer Matrix provides data on the numbers of students transferring from Oklahoma public and private institutions of higher education to other Oklahoma institutions, using data from receiving institutions. Among the highlights are: the number of students who transferred to four-year and two-year institutions remained steady at 57.8…
Transfer matrix representation for periodic planar media
NASA Astrophysics Data System (ADS)
Parrinello, A.; Ghiringhelli, G. L.
2016-06-01
Sound transmission through infinite planar media characterized by in-plane periodicity is faced by exploiting the free wave propagation on the related unit cells. An appropriate through-thickness transfer matrix, relating a proper set of variables describing the acoustic field at the two external surfaces of the medium, is derived by manipulating the dynamic stiffness matrix related to a finite element model of the unit cell. The adoption of finite element models avoids analytical modeling or the simplification on geometry or materials. The obtained matrix is then used in a transfer matrix method context, making it possible to combine the periodic medium with layers of different nature and to treat both hard-wall and semi-infinite fluid termination conditions. A finite sequence of identical sub-layers through the thickness of the medium can be handled within the transfer matrix method, significantly decreasing the computational burden. Transfer matrices obtained by means of the proposed method are compared with analytical or equivalent models, in terms of sound transmission through barriers of different nature.
Vadali, Ramkumar V; Shi, Yan; Kumar, Sameer; Kale, Laxmikant V; Tuckerman, Mark E; Martyna, Glenn J
2004-12-01
Many systems of great importance in material science, chemistry, solid-state physics, and biophysics require forces generated from an electronic structure calculation, as opposed to an empirically derived force law to describe their properties adequately. The use of such forces as input to Newton's equations of motion forms the basis of the ab initio molecular dynamics method, which is able to treat the dynamics of chemical bond-breaking and -forming events. However, a very large number of electronic structure calculations must be performed to compute an ab initio molecular dynamics trajectory, making the efficiency as well as the accuracy of the electronic structure representation critical issues. One efficient and accurate electronic structure method is the generalized gradient approximation to the Kohn-Sham density functional theory implemented using a plane-wave basis set and atomic pseudopotentials. The marriage of the gradient-corrected density functional approach with molecular dynamics, as pioneered by Car and Parrinello (R. Car and M. Parrinello, Phys Rev Lett 1985, 55, 2471), has been demonstrated to be capable of elucidating the atomic scale structure and dynamics underlying many complex systems at finite temperature. However, despite the relative efficiency of this approach, it has not been possible to obtain parallel scaling of the technique beyond several hundred processors on moderately sized systems using standard approaches. Consequently, the time scales that can be accessed and the degree of phase space sampling are severely limited. To take advantage of next generation computer platforms with thousands of processors such as IBM's BlueGene, a novel scalable parallelization strategy for Car-Parrinello molecular dynamics is developed using the concept of processor virtualization as embodied by the Charm++ parallel programming system. Charm++ allows the diverse elements of a Car-Parrinello molecular dynamics calculation to be interleaved with low
NASA Astrophysics Data System (ADS)
Schmidt, C. H.; Laitinen, T. A.; Eibert, T. F.
2011-10-01
Near-field measurement and transformation techniques are widely applied to characterize radiation patterns of antennas. Spherical and cylindrical near-field measurements have been researched extensively and various techniques with different probe compensation capabilities and complexities exist. Among those techniques applicable for (almost) arbitrary probes, the crucial computational efficiency has been achieved through the use of Fast Fourier Transform based preprocessing of the measurement data. It is shown in this paper that the Fast Fourier Transform based preprocessing can also be utilized in conjunction with the plane wave based fully probe-corrected near-field far-field transformation with low numerical complexity. The collection of probe signals is split into smaller subsets for individual orthogonal azimuthal Fourier modes by an Inverse Fast Fourier Transform. These smaller subsets can be transformed to the far field very efficiently with full probe correction. The technique presented in this paper is applicable for arbitrary "body of revolution" antenna measurement grids, including the important cases of cylindrical and spherical measurement grids. The "body of revolution" grids are rotationally symmetric around the z-axis and the probe signals must be available equidistantly in ϕ.
Propagation of aberrated wavefronts using a ray transfer matrix.
Raasch, Thomas W
2014-05-01
A ray transfer matrix is used to calculate the propagation of aberrated wavefronts across a homogeneous refractive index. The wavefront is represented by local surface normals, i.e., by a ray bundle, and the propagation is accomplished by transferring those rays across the space. Wavefront shape is generated from the slopes and positions of the collection of rays. Calculation methods are developed for the paraxial case, for higher-order expansions, and for the exact tangent case. A numerical example is used to compare results between an analytical method and the methods developed here.
Transfer matrix for treating stratified media including birefringent crystals.
Essinger-Hileman, Thomas
2013-01-10
Birefringent crystals are extensively used to manipulate polarized light. The generalized transfer matrix developed allows efficient calculation of the full polarization state of light transmitted through and reflected by a stack of arbitrarily many discrete layers of isotropic and birefringent materials at any frequency and angle of incidence. The matrix of a uniaxial birefringent crystal with arbitrary rotation is calculated, along with its reduction to the matrix of an isotropic medium. This method is of great practical importance where tight control of systematic effects is needed in optical systems employing birefringent crystals, one example being wave plates used by cosmic microwave background polarimetry with wide field-of-view telescopes.
The transfer matrix approach to circular graphene quantum dots
NASA Astrophysics Data System (ADS)
Chau Nguyen, H.; Nguyen, Nhung T. T.; Nguyen, V. Lien
2016-07-01
We adapt the transfer matrix (T-matrix) method originally designed for one-dimensional quantum mechanical problems to solve the circularly symmetric two-dimensional problem of graphene quantum dots. Similar to one-dimensional problems, we show that the generalized T-matrix contains rich information about the physical properties of these quantum dots. In particular, it is shown that the spectral equations for bound states as well as quasi-bound states of a circular graphene quantum dot and related quantities such as the local density of states and the scattering coefficients are all expressed exactly in terms of the T-matrix for the radial confinement potential. As an example, we use the developed formalism to analyse physical aspects of a graphene quantum dot induced by a trapezoidal radial potential. Among the obtained results, it is in particular suggested that the thermal fluctuations and electrostatic disorders may appear as an obstacle to controlling the valley polarization of Dirac electrons.
An improved transfer-matrix model for optical superlenses.
Moore, Ciaran P; Blaikie, Richard J; Arnold, Matthew D
2009-08-01
The use of transfer-matrix analyses for characterizing planar optical superlensing systems is studied here, and the simple model of the planar superlens as an isolated imaging element is shown to be defective in certain situations. These defects arise due to neglected interactions between the superlens and the spatially varying shadow masks that are normally used as scattering objects for imaging, and which are held in near-field proximity to the superlenses. An extended model is proposed that improves the accuracy of the transfer-matrix analysis, without adding significant complexity, by approximating the reflections from the shadow mask by those from a uniform metal layer. Results obtained using both forms of the transfer matrix model are compared to finite element models and two example superlenses, one with a silver monolayer and the other with three silver sublayers, are characterized. The modified transfer matrix model gives much better agreement in both cases.
110x110 optical mode transfer matrix inversion.
Carpenter, Joel; Eggleton, Benjamin J; Schröder, Jochen
2014-01-13
The largest complete mode transfer matrix of a fiber is measured consisting of 110 spatial and polarization modes. This matrix is then inverted and the pattern required to produce a desired output at the receiver are launched at the transmitter.
Transfer-matrix approach for finite-difference time-domain simulation of periodic structures.
Deinega, Alexei; Belousov, Sergei; Valuev, Ilya
2013-11-01
Optical properties of periodic structures can be calculated using the transfer-matrix approach, which establishes a relation between amplitudes of the wave incident on a structure with transmitted or reflected waves. The transfer matrix can be used to obtain transmittance and reflectance spectra of finite periodic structures as well as eigenmodes of infinite structures. Traditionally, calculation of the transfer matrix is performed in the frequency domain and involves linear algebra. In this work, we present a technique for calculation of the transfer matrix using the finite-difference time-domain (FDTD) method and show the way of its implementation in FDTD code. To illustrate the performance of our technique we calculate the transmittance spectra for opal photonic crystal slabs consisting of multiple layers of spherical scatterers. Our technique can be used for photonic band structure calculations. It can also be combined with existing FDTD methods for the analysis of periodic structures at an oblique incidence, as well as for modeling point sources in a periodic environment. PMID:24329377
Transfer-matrix approach for finite-difference time-domain simulation of periodic structures.
Deinega, Alexei; Belousov, Sergei; Valuev, Ilya
2013-11-01
Optical properties of periodic structures can be calculated using the transfer-matrix approach, which establishes a relation between amplitudes of the wave incident on a structure with transmitted or reflected waves. The transfer matrix can be used to obtain transmittance and reflectance spectra of finite periodic structures as well as eigenmodes of infinite structures. Traditionally, calculation of the transfer matrix is performed in the frequency domain and involves linear algebra. In this work, we present a technique for calculation of the transfer matrix using the finite-difference time-domain (FDTD) method and show the way of its implementation in FDTD code. To illustrate the performance of our technique we calculate the transmittance spectra for opal photonic crystal slabs consisting of multiple layers of spherical scatterers. Our technique can be used for photonic band structure calculations. It can also be combined with existing FDTD methods for the analysis of periodic structures at an oblique incidence, as well as for modeling point sources in a periodic environment.
Kim, Yoon Jae; Kim, Yoon Young
2010-10-01
This paper presents a numerical method for the optimization of the sequencing of solid panels, perforated panels and air gaps and their respective thickness for maximizing sound transmission loss and/or absorption. For the optimization, a method based on the topology optimization formulation is proposed. It is difficult to employ only the commonly-used material interpolation technique because the involved layers exhibit fundamentally different acoustic behavior. Thus, an optimization method formulation using a so-called unified transfer matrix is newly proposed. The key idea is to form elements of the transfer matrix such that interpolated elements by the layer design variables can be those of air, perforated and solid panel layers. The problem related to the interpolation is addressed and bench mark-type problems such as sound transmission or absorption maximization problems are solved to check the efficiency of the developed method. PMID:20968351
Farina, Dmytro; Jiang, Y; Dössel, O
2009-12-01
The distributions of transmembrane voltage (TMV) within the cardiac tissue are linearly connected with the patient's body surface potential maps (BSPMs) at every time instant. The matrix describing the relation between the respective distributions is referred to as the transfer matrix. This matrix can be employed to carry out forward calculations in order to find the BSPM for any given distribution of TMV inside the heart. Its inverse can be used to reconstruct the cardiac activity non-invasively, which can be an important diagnostic tool in the clinical practice. The computation of this matrix using the finite element method can be quite time-consuming. In this work, a method is proposed allowing to speed up this process by computing an approximate transfer matrix instead of the precise one. The method is tested on three realistic anatomical models of real-world patients. It is shown that the computation time can be reduced by 50% without loss of accuracy.
Ray transfer matrix for a spiral phase plate.
Eggleston, M; Godat, T; Munro, E; Alonso, M A; Shi, H; Bhattacharya, M
2013-12-01
We present a ray transfer matrix for a spiral phase plate. Using this matrix we determine the stability of an optical resonator made of two spiral phase plates and trace stable ray orbits in the resonator. Our results should be relevant to laser physics, optical micromanipulation, quantum information, and optomechanics.
Application of the transfer matrix for tuning the CSNS-DTL
NASA Astrophysics Data System (ADS)
Li, A.-Hong; Yin, Xue-Jun; Fu, Shi-Nian; Sun, Zhi-Rui
2011-10-01
In the construction of a drift tube LINAC (DTL), many factors caused during the fabrication and assembly of the structure cells cause the electric field distribution not as the same as the design curve. To solve this problem, the traditional way is to solve the equation of Slater's perturbation theorem to obtain the electrical field variation due to local frequency shift. However, that is very difficult under complicated conditions. Since the field perturbation equation is similar to the particle's transverse motion equation, which can be simply solved by using the transfer matrix method, we thus propose to apply a transfer matrix method in tuning the DTL. We demonstrate the availability and advantages of this method with 3D microwave code simulation and the LabVIEW calculation program. After two iterations, the initial error of the electric field of 19.5% has been improved greatly down to 1.3%-4.5%. This indicates that the transfer matrix method is very useful and convenient for the simplification of tuning procedures.
NASA Astrophysics Data System (ADS)
Banerjee, Partha P.; Li, Han; Aylo, Rola; Nehmetallah, Georges
2011-10-01
The development of electromagnetic (EM) metamaterials for perfect lensing and optical cloaking has given rise to novel multilayer bandgap structures using stacks of positive and negative index materials. Propagation of a collection of TE or TM plane waves, comprising the angular plane wave spectrum, through such structures is analyzed by using the transfer matrix method (TMM) on every plane wave component. Results obtained from this TMM approach for a Gaussian spectrum are compared with those using standard FEM techniques.
Rivero, Pablo; Loschen, Christoph; Moreira, Ibério De P R; Illas, Francesc
2009-11-15
This work explores the performance of periodic plane wave density functional theory calculations with an on-site Coulomb correction to the standard LDA and GGA exchange-correlation potential--commonly used to describe strongly correlated solids--in describing the magnetic coupling constant of a series of molecular compounds representative of dinuclear Cu complexes and of organic diradicals. The resulting LDA+U or GGA+U formalisms, lead to results comparable to experiment and to those obtained by means of standard hybrid functionals provided that the value of the U parameter is adequately chosen. Hence, these methods offer an alternative efficient computational scheme to correct LDA and GGA approaches to adequately describe the electronic structure and magnetic coupling in large molecular magnetic systems, although at the expenses of introducing an empirical (U) parameter. For all investigated copper dinuclear systems, the LDA+U and GGA+U approaches lead to an improvement in the description of magnetic properties over the original LDA and GGA schemes with an accuracy similar to that arising from the hybrid B3LYP functional, by increasing the on-site Coulomb repulsion with a moderate U value. Nevertheless, the introduction of an arbitrary U value in the 0-10 eV range most often provides the correct ground-state spin distribution and the correct sign of the magnetic coupling constant.
Alimonti, Luca; Atalla, Noureddine; Berry, Alain; Sgard, Franck
2014-05-01
Modeling complex vibroacoustic systems including poroelastic materials using finite element based methods can be unfeasible for practical applications. For this reason, analytical approaches such as the transfer matrix method are often preferred to obtain a quick estimation of the vibroacoustic parameters. However, the strong assumptions inherent within the transfer matrix method lead to a lack of accuracy in the description of the geometry of the system. As a result, the transfer matrix method is inherently limited to the high frequency range. Nowadays, hybrid substructuring procedures have become quite popular. Indeed, different modeling techniques are typically sought to describe complex vibroacoustic systems over the widest possible frequency range. As a result, the flexibility and accuracy of the finite element method and the efficiency of the transfer matrix method could be coupled in a hybrid technique to obtain a reduction of the computational burden. In this work, a hybrid methodology is proposed. The performances of the method in predicting the vibroacoutic indicators of flat structures with attached homogeneous acoustic treatments are assessed. The results prove that, under certain conditions, the hybrid model allows for a reduction of the computational effort while preserving enough accuracy with respect to the full finite element solution.
NASA Astrophysics Data System (ADS)
Cave, Robert J.; Newton, Marshall D.
1996-01-01
A new method for the calculation of the electronic coupling matrix element for electron transfer processes is introduced and results for several systems are presented. The method can be applied to ground and excited state systems and can be used in cases where several states interact strongly. Within the set of states chosen it is a non-perturbative treatment, and can be implemented using quantities obtained solely in terms of the adiabatic states. Several applications based on quantum chemical calculations are briefly presented. Finally, since quantities for adiabatic states are the only input to the method, it can also be used with purely experimental data to estimate electron transfer matrix elements.
Ray-transfer-matrix approach to unstable resonator analysis.
Ewanizky, T F
1979-03-01
A parametric analysis of unstable resonators is described. The resonator is mathematically represented by an appropriate ray-transfer-matrix, and changes in Gaussian beam parameters are calculated after propagation through the optical structure. The results highlight an inherent selective property that presents an effective loss mechanism for divergent radiation. This selective property is shown to be dependent on the resonator parameters of optical magnification and confocal length error. The analysis concludes that the initially backward-propagating radiation during the prelasing period is important in establishing low threshold and good beam quality in confocal unstable-resonator lasers. PMID:20208805
NASA Astrophysics Data System (ADS)
Varney, Philip; Green, Itzhak
2014-11-01
Numerous methods are available to calculate rotordynamic whirl frequencies, including analytic methods, finite element analysis, and the transfer matrix method. The typical real-valued transfer matrix (RTM) suffers from several deficiencies, including lengthy computation times and the inability to distinguish forward and backward whirl. Though application of complex coordinates in rotordynamic analysis is not novel per se, specific advantages gained from using such coordinates in a transfer matrix analysis have yet to be elucidated. The present work employs a complex coordinate redefinition of the transfer matrix to obtain reduced forms of the elemental transfer matrices in inertial and rotating reference frames, including external stiffness and damping. Application of the complex-valued state variable redefinition results in a reduction of the 8×8 RTM to the 4×4 Complex Transfer Matrix (CTM). The CTM is advantageous in that it intrinsically separates forward and backward whirl, eases symbolic manipulation by halving the transfer matrices’ dimension, and provides significant improvement in computation time. A symbolic analysis is performed on a simple overhung rotor to demonstrate the mathematical motivation for whirl frequency separation. The CTM's utility is further shown by analyzing a rotordynamic system supported by viscoelastic elastomer rings. Viscoelastic elastomer ring supports can provide significant damping while reducing the cost and complexity associated with conventional components such as squeeze film dampers. The stiffness and damping of a viscoelastic damper ring are determined herein as a function of whirl frequency using the viscoelastic correspondence principle and a constitutive fractional calculus viscoelasticity model. The CTM is then employed to obtain the characteristic equation, where the whirl frequency dependent stiffness and damping of the elastomer supports are included. The Campbell diagram is shown, demonstrating the CTM
NASA Astrophysics Data System (ADS)
Noor, Fatimah A.; Abdullah, Mikrajuddin; Sukirno; Khairurrijal
2010-12-01
Analytical expressions of electron transmittance and tunneling current in an anisotropic TiNx/HfO2/SiO2/p-Si(100) metal—oxide—semiconductor (MOS) capacitor were derived by considering the coupling of transverse and longitudinal energies of an electron. Exponential and Airy wavefunctions were utilized to obtain the electron transmittance and the electron tunneling current. A transfer matrix method, as a numerical approach, was used as a benchmark to assess the analytical approaches. It was found that there is a similarity in the transmittances calculated among exponential- and Airy-wavefunction approaches and the TMM at low electron energies. However, for high energies, only the transmittance calculated by using the Airy-wavefunction approach is the same as that evaluated by the TMM. It was also found that only the tunneling currents calculated by using the Airy-wavefunction approach are the same as those obtained under the TMM for all range of oxide voltages. Therefore, a better analytical description for the tunneling phenomenon in the MOS capacitor is given by the Airy-wavefunction approach. Moreover, the tunneling current density decreases as the titanium concentration of the TiNx metal gate increases because the electron effective mass of TiNx decreases with increasing nitrogen concentration. In addition, the mass anisotropy cannot be neglected because the tunneling currents obtained under the isotropic and anisotropic masses are very different.
Development of a hybrid wave based-transfer matrix model for sound transmission analysis.
Dijckmans, A; Vermeir, G
2013-04-01
In this paper, a hybrid wave based-transfer matrix model is presented that allows for the investigation of the sound transmission through finite multilayered structures placed between two reverberant rooms. The multilayered structure may consist of an arbitrary configuration of fluid, elastic, or poro-elastic layers. The field variables (structural displacements and sound pressures) are expanded in terms of structural and acoustic wave functions. The boundary and continuity conditions in the rooms determine the participation factors in the pressure expansions. The displacement of the multilayered structure is determined by the mechanical impedance matrix, which gives a relation between the pressures and transverse displacements at both sides of the structure. The elements of this matrix are calculated with the transfer matrix method. First, the hybrid model is numerically validated. Next a comparison is made with sound transmission loss measurements of a hollow brick wall and a sandwich panel. Finally, numerical simulations show the influence of structural damping, room dimensions and plate dimensions on the sound transmission loss of multilayered structures.
Guedra, Matthieu; Penelet, Guillaume; Lotton, Pierrick; Dalmont, Jean-Pierre
2011-07-01
The aim of this paper is to propose a method to predict the onset conditions of the thermoacoustic instability for various thermoacoustic engines. As an accurate modeling of the heat exchangers and the stack submitted to a temperature gradient is a difficult task, an experimental approach for the characterization of the amplifying properties of the thermoacoustic core is proposed. An experimental apparatus is presented which allows to measure the transfer matrix of a thermoacoustic core under various heating conditions by means of a four-microphone method. An analytical model for the prediction of the onset conditions from this measured transfer matrix is developed. The experimental data are introduced in the model and theoretical predictions of the onset conditions are compared with those actually observed in standing-wave and traveling-wave engines. The results show good agreement between predictions from the model and experiments.
Wave transfer matrix for a spiral phase plate.
Rumala, Yisa S
2015-05-10
The wave transfer matrix (WTM) is applied to calculating various characteristics of a spiral phase plate (SPP) for the first time to our knowledge. This approach provides a more convenient and systematic approach to calculating properties of a multilayered SPP device. In particular, it predicts the optical wave characteristics on the input and output plane of the device when the SPP is fabricated on a substrate of the same refractive index as the SPP as well as on a substrate of a different refractive index compared to the SPP. The dependence of the parameters on the input laser frequency is studied in detail for a low finesse SPP etalon device for both cases. The equations derived from the WTM are used to show that a variation in input laser frequency causes the optical intensity pattern on the output plane to rotate, while preserving the topology of the optical vortex, i.e., the variation in laser frequency has a minimal effect on the parameters describing the azimuthal intensity modulation and orbital angular momentum content of the beam. In addition, the equations predict the presence of longitudinal modes in the SPP device.
Transfer matrix approach for the Kerr and Faraday rotation in layered nanostructures
NASA Astrophysics Data System (ADS)
Széchenyi, Gábor; Vigh, Máté; Kormányos, Andor; Cserti, József
2016-09-01
To study the optical rotation of the polarization of light incident on multilayer systems consisting of atomically thin conductors and dielectric multilayers we present a general method based on transfer matrices. The transfer matrix of the atomically thin conducting layer is obtained using the Maxwell equations. We derive expressions for the Kerr (Faraday) rotation angle and for the ellipticity of the reflected (transmitted) light as a function of the incident angle and polarization of the light. The method is demonstrated by calculating the Kerr (Faraday) angle for bilayer graphene in the quantum anomalous Hall state placed on the top of dielectric multilayers. The optical conductivity of the bilayer graphene is calculated in the framework of a four-band model.
Transfer matrix approach for the Kerr and Faraday rotation in layered nanostructures.
Széchenyi, Gábor; Vigh, Máté; Kormányos, Andor; Cserti, József
2016-09-21
To study the optical rotation of the polarization of light incident on multilayer systems consisting of atomically thin conductors and dielectric multilayers we present a general method based on transfer matrices. The transfer matrix of the atomically thin conducting layer is obtained using the Maxwell equations. We derive expressions for the Kerr (Faraday) rotation angle and for the ellipticity of the reflected (transmitted) light as a function of the incident angle and polarization of the light. The method is demonstrated by calculating the Kerr (Faraday) angle for bilayer graphene in the quantum anomalous Hall state placed on the top of dielectric multilayers. The optical conductivity of the bilayer graphene is calculated in the framework of a four-band model.
Song; Bolton
2000-03-01
A method for evaluating the acoustical properties of homogeneous and isotropic porous materials that may be modeled as fluids having complex properties is described here. To implement the procedure, a conventional, two-microphone standing wave tube was modified to include: a new sample holder; a section downstream of the sample holder that accommodated a second pair of microphone holders and an approximately anechoic termination. Sound-pressure measurements at two upstream and two downstream locations were then used to estimate the two-by-two transfer matrix of porous material samples. The experimental transfer matrix method has been most widely used in the past to measure the acoustical properties of silencer system components. That procedure was made more efficient here by taking advantage of the reciprocal nature of sound transmission through homogeneous and isotropic porous layers. The transfer matrix of a homogeneous and isotropic, rigid or limp porous layer can easily be used to identify the material's characteristic impedance and wave number, from which other acoustical quantities of interest can be calculated. The procedure has been used to estimate the acoustical properties of a glass fiber material: good agreement was found between the estimated acoustical properties and those predicted by using the formulas of Delany and Bazley.
Left-handed materials and negative refraction: Transfer matrix and FDTD calculations
NASA Astrophysics Data System (ADS)
Soukoulis, Costas M.
2004-03-01
We will present transfer matrix calculations of metallic wires, split ring resonators (SRR) and left-handed materials (LHM). Our results [1] show that the transfer matrix method can capture all the details characteristics of the metamaterials. In particular the dependence of the resonance frequency and its width on the structural parameters of the SRR and the size of the unit cell is studied. Also the dependence of the imaginary part of effective permittivity of arrays of metallic wires is studied in detail. It is found [2,3] that the imaginary part of effective permittivity has small values even for wires as small as 20 micron in diameter. The transfer matrix is very useful in calculating both the amplitude and the phase of the transmission and reflection coefficient. These numerical data was used [4] in the determination of the effective parameters of the metamaterials. It was indeed found that the refractive index was unambiguously negative in the frequency region where both ɛ and μ were negative. Finally, we will show that SRR have a strong electric response, equivalent to that of cut wires [5], which dominates the response of LHM. A new criterion is introduced to clearly identify if an experimental expression peak is left- or right handed. Finite difference time domain (FDTD) simulations will be presented for the transmission of the EM wave through the interface of the positive and negative refraction index. It is found [6] that the wave is trapped temporarily at the interface and after a long time the wave front moves eventually in the direction of negative refraction. The differences between negative refraction in photonic crystals and left-handed materials will be also discussed. Work supported by US-DOE, DARPA, NSF and EU (DALHM project). References: [1] P. Markos and C. M. Soukoulis, Phys. Rev. B 65, 033401 (2002); Phys. Rev. E 65, 036622 (2002). [2] P. Markos, I. Rousochatzakis and C. M. Soukoulis, Phys. Rev. B 66, 045601 (2002). [3] P. Markos and C. M
NASA Technical Reports Server (NTRS)
Cramer, Nick; Swei, Sean Shan-Min; Cheung, Kenny; Teodorescu, Mircea
2015-01-01
This paper presents a modeling and control of aerostructure developed by lattice-based cellular materials/components. The proposed aerostructure concept leverages a building block strategy for lattice-based components which provide great adaptability to varying ight scenarios, the needs of which are essential for in- ight wing shaping control. A decentralized structural control design is proposed that utilizes discrete-time lumped mass transfer matrix method (DT-LM-TMM). The objective is to develop an e ective reduced order model through DT-LM-TMM that can be used to design a decentralized controller for the structural control of a wing. The proposed approach developed in this paper shows that, as far as the performance of overall structural system is concerned, the reduced order model can be as e ective as the full order model in designing an optimal stabilizing controller.
Transfer matrix theory of monolayer graphene/bilayer graphene heterostructure superlattice
Wang, Yu
2014-10-28
We have formulated a transfer matrix method to investigate electronic properties of graphene heterostructure consisting of monolayer graphene and bilayer counterpart. By evaluating transmission, conductance, and band dispersion, we show that, irrespective of the different carrier chiralities in monolayer graphene and bilayer graphene, superlattice consisting of biased bilayer graphene barrier and monolayer graphene well can mimic the electronic properties of conventional semiconductor superlattice, displaying the extended subbands in the quantum tunneling regime and producing anisotropic minigaps for the classically allowed transport. Due to the lateral confinement, the lowest mode has shifted away from the charge neutral point of monolayer graphene component, opening a sizeable gap in concerned structure. Following the gate-field and geometry modulation, all electronic states and gaps between them can be externally engineered in an electric-controllable strategy.
Generalized ray-transfer matrix for an optical element having an arbitrary wavefront aberration.
Jeong, Tae Moon; Ko, Do-Kyeong; Lee, Jongmin
2005-11-15
A generalized ray-transfer matrix for describing the action of an optical element having an arbitrary wavefront aberration is obtained. In this generalized ray-transfer matrix, the action of the aberrated optical element is represented by the product of radial ray-transfer matrices and tangential ray-transfer matrices. The refraction angle of an incident ray is calculated from the gradient of the wavefront aberration at the point of incidence, and the radial and tangential ray-transfer matrices directly use the gradient as a matrix component. To show the validity of the generalized ray-transfer matrix, intercept heights from a spot diagram are calculated with the generalized ray-transfer matrix and compared with those calculated with commercial ray-tracing software.
Doutres, Olivier; Atalla, Noureddine; Osman, Haisam
2015-06-01
Porous materials are widely used for improving sound absorption and sound transmission loss of vibrating structures. However, their efficiency is limited to medium and high frequencies of sound. A solution for improving their low frequency behavior while keeping an acceptable thickness is to embed resonant structures such as Helmholtz resonators (HRs). This work investigates the absorption and transmission acoustic performances of a cellular porous material with a two-dimensional periodic arrangement of HR inclusions. A low frequency model of a resonant periodic unit cell based on the parallel transfer matrix method is presented. The model is validated by comparison with impedance tube measurements and simulations based on both the finite element method and a homogenization based model. At the HR resonance frequency (i) the transmission loss is greatly improved and (ii) the sound absorption of the foam can be either decreased or improved depending on the HR tuning frequency and on the thickness and properties of the host foam. Finally, the diffuse field sound absorption and diffuse field sound transmission loss performance of a 2.6 m(2) resonant cellular material are measured. It is shown that the improvements observed at the Helmholtz resonant frequency on a single cell are confirmed at a larger scale. PMID:26093437
Doutres, Olivier; Atalla, Noureddine; Osman, Haisam
2015-06-01
Porous materials are widely used for improving sound absorption and sound transmission loss of vibrating structures. However, their efficiency is limited to medium and high frequencies of sound. A solution for improving their low frequency behavior while keeping an acceptable thickness is to embed resonant structures such as Helmholtz resonators (HRs). This work investigates the absorption and transmission acoustic performances of a cellular porous material with a two-dimensional periodic arrangement of HR inclusions. A low frequency model of a resonant periodic unit cell based on the parallel transfer matrix method is presented. The model is validated by comparison with impedance tube measurements and simulations based on both the finite element method and a homogenization based model. At the HR resonance frequency (i) the transmission loss is greatly improved and (ii) the sound absorption of the foam can be either decreased or improved depending on the HR tuning frequency and on the thickness and properties of the host foam. Finally, the diffuse field sound absorption and diffuse field sound transmission loss performance of a 2.6 m(2) resonant cellular material are measured. It is shown that the improvements observed at the Helmholtz resonant frequency on a single cell are confirmed at a larger scale.
Thuraisingham, Ranjit Arulnayagam
2011-11-01
A procedure based on the multiple expansion of the brain electrical generator is used here to derive analytical expressions for the transfer matrix necessary to obtain potentials referenced to infinity. Its features include: avoidance of computations that involve a large number of discrete dipole sources; faster evaluation compared to the use of the dipole layer; and a transparency showing the parameters that constitute the transfer matrix. The paper also proposes the construction of the standardization matrix without the use of the general inverse of a non-symmetrical matrix.
Alimonti, Luca; Atalla, Noureddine; Berry, Alain; Sgard, Franck
2015-02-01
Practical vibroacoustic systems involve passive acoustic treatments consisting of highly dissipative media such as poroelastic materials. The numerical modeling of such systems at low to mid frequencies typically relies on substructuring methodologies based on finite element models. Namely, the master subsystems (i.e., structural and acoustic domains) are described by a finite set of uncoupled modes, whereas condensation procedures are typically preferred for the acoustic treatments. However, although accurate, such methodology is computationally expensive when real life applications are considered. A potential reduction of the computational burden could be obtained by approximating the effect of the acoustic treatment on the master subsystems without introducing physical degrees of freedom. To do that, the treatment has to be assumed homogeneous, flat, and of infinite lateral extent. Under these hypotheses, simple analytical tools like the transfer matrix method can be employed. In this paper, a hybrid finite element-transfer matrix methodology is proposed. The impact of the limiting assumptions inherent within the analytical framework are assessed for the case of plate-cavity systems involving flat and homogeneous acoustic treatments. The results prove that the hybrid model can capture the qualitative behavior of the vibroacoustic system while reducing the computational effort.
Truncating an exact matrix product state for the XY model: Transfer matrix and its renormalization
NASA Astrophysics Data System (ADS)
Rams, Marek M.; Zauner, Valentin; Bal, Matthias; Haegeman, Jutho; Verstraete, Frank
2015-12-01
We discuss how to analytically obtain an essentially infinite matrix product state (MPS) representation of the ground state of the XY model. On one hand this allows us to illustrate how the Ornstein-Zernike form of the correlation function emerges in the exact case using standard MPS language. On the other hand we study the consequences of truncating the bond dimension of the exact MPS, which is also part of many tensor network algorithms, and analyze how the truncated MPS transfer matrix is representing the dominant part of the exact quantum transfer matrix. In the gapped phase we observe that the correlation length obtained from a truncated MPS approaches the exact value following a power law in effective bond dimension. In the gapless phase we find a good match between a state obtained numerically from standard MPS techniques with finite bond dimension and a state obtained by effective finite imaginary time evolution in our framework. This provides a direct hint for a geometric interpretation of finite entanglement scaling at the critical point in this case. Finally, by analyzing the spectra of transfer matrices, we support the interpretation put forward by V. Zauner et al. [New J. Phys. 17, 053002 (2015), 10.1088/1367-2630/17/5/053002] that the MPS transfer matrix emerges from the quantum transfer matrix though the application of Wilson's numerical renormalization group along the imaginary-time direction.
NASA Astrophysics Data System (ADS)
Wang, Liang; Tao, Kunwang; Qian, Xinlin
2015-04-01
With the increasing developments of islands, the protection and management of island's natural resources are imperative. The core of islands' protection and management is to acquire the information of changes of the land use and land cover. What's more, the purpose of the islands' land use change information analysis is to plan the effective protection of land resource, achieve scientific management and sustainable utilization. Based on the improved calculation method of land use change and the computational model of change rate of the land use, an analysis of land use transfer matrix and transfer probability matrix is presented, and the method of land use change analysis based on the transfer matrix is proposed in this paper. And then the comparative analysis of all types of land use transfer is introduced. Taken the island of Dongtou in Zhejiang Province as the case, with the SPOT-5 satellite image in 2005 and the aerial image in 2011 as the data source, the current situation of land utilization of Dongtou Island and its land use change are analyzed. The experiment results show that, from 2005 to 2011, the greatest changes are the structures and water, followed by the forest land, grassland, cultivated land and others. The major change of structure and forest is the net change, while the major change of the water and grassland is the swap change. From the perspective of increment, the conversion from waters to structure has the most advantage, followed by water converted to grassland and road. To see from the loss, structures converted into roads and buildings have the most superiority transformation, followed by structures converted to grassland. The analysis of the case proves that the proposed process and method in this paper could achieve better results in the practical application. The experiment results also demonstrate that the proposed method could effectively obtain the dynamic change information of land use which is much helpful for land management and
NASA Astrophysics Data System (ADS)
Akimenko, S. S.; Gorbunov, V. A.; Myshlyavtsev, A. V.; Fefelov, V. F.
2015-09-01
A lattice gas model of monodentate organic molecules on a solid surface in terms of pair directional interactions has been developed. As a special case of the constructed model the self-organization of CaTBPP on Au(111) surface was studied with Monte Carlo and transfer-matrix methods in the grand canonical ensemble. It is shown that the adsorbed molecules tend to form dimers when the hydrogen bonding between the molecules is relatively strong. Phase behavior of the system in this case can be characterized as the hierarchical self-assembly process. The self-assembly is led by the repulsive interactions between the building blocks those are the dimers of the adsorbate molecules stabilized with the strong hydrogen bonding. When hydrogen bonding is weak, a cross-like structure appears at moderate surface coverages.
Vibration localization in mono- and bi-coupled bladed disks - A transfer matrix approach
NASA Technical Reports Server (NTRS)
Ottarsson, Gisli; Pierre, Christophe
1993-01-01
A transfer matrix approach to the analysis of the dynamics of mistuned bladed disks is presented. The study focuses on mono-coupled systems, in which each blade is coupled to its two neighboring blades, and bi-coupled systems, where each blade is coupled to its four nearest neighbors. Transfer matrices yield the free dynamics, both the characteristic free wave and the normal modes - in closed form for the tuned assemblies. Mistuned assemblies are represented by random transfer matrices and an examination of the effect of mistuning on harmonic wave propagation yields the localization factor - the average rate of spatial wave amplitude decay per blade - in the mono-coupled assembly. Based on a comparison of the wave propagation characteristics of the mono- and bi-coupled assemblies, important conclusions are drawn about the effect of the additional coupling coordinate on the sensitivity to mistuning and the strength of mode localization predicted by a mono-coupled analysis.
Transfer matrix analysis of backscattering and reflection effects on WDM-PON systems.
Simatupang, Joni Welman; Lee, San-Liang
2013-11-18
This paper proposes using power transfer matrix analysis to characterize the effects of Rayleigh backscattering and Fresnel reflection on WDM-PON systems. The modeling of a WDM-PON system can be carried out simply by matrix multiplication of the corresponding matrices for all the building blocks, where all possible guided backward lights and resonant configurations along the optical network can be accounted for. The total sum of all interferences affecting the bidirectional transmission that leads to an optical crosstalk-to-signal (C/S) ratio can be modeled as back-reflections through cascaded two-port networks for the downstream and upstream signals. This approach is simple, robust, efficient, and also accurate. Its accuracy is verified for simple system architectures and then applied to study more complicated cases. The results show its versatility to analyze a wide variety of bidirectional optical transmission systems.
Transfer-matrix study of a hard-square lattice gas with two kinds of particles and density anomaly.
Oliveira, Tiago J; Stilck, Jürgen F
2015-09-01
Using transfer matrix and finite-size scaling methods, we study the thermodynamic behavior of a lattice gas with two kinds of particles on the square lattice. Only excluded volume interactions are considered, so that the model is athermal. Large particles exclude the site they occupy and its four first neighbors, while small particles exclude only their site. Two thermodynamic phases are found: a disordered phase where large particles occupy both sublattices with the same probability and an ordered phase where one of the two sublattices is preferentially occupied by them. The transition between these phases is continuous at small concentrations of the small particles and discontinuous at larger concentrations, both transitions are separated by a tricritical point. Estimates of the central charge suggest that the critical line is in the Ising universality class, while the tricritical point has tricritical Ising (Blume-Emery-Griffiths) exponents. The isobaric curves of the total density as functions of the fugacity of small or large particles display a minimum in the disordered phase.
NASA Astrophysics Data System (ADS)
Bowen, Patrick T.; Urzhumov, Yaroslav A.
2016-04-01
Acoustic metamaterial structures with discrete and continuous rotational symmetries attract interest of theorists and engineers due to the relative simplicity of their design and fabrication. They are also likely candidates for omnidirectional acoustic cloaking and other transformation-acoustical novelties. In this paper, we employ a stratified description of such structures, and develop the theory and an efficient symbolic/numerical algorithm for analyzing the scattering properties of such structures immersed in homogeneous fluid environments. The algorithm calculates the partial scattering amplitudes and the related scattering phases for an arbitrary layered distribution of acoustic material properties. The efficiency of the algorithm enables us to find approximate solutions to certain inverse scattering problems through quasi-global optimization. The scattering problems addressed here are the three forms of cloaking: (1) extinction cross-section suppression, the canonical form of cloaking, (2) monostatic sonar invisibility (backscattering suppression), and (3) acoustic force cloaking (transport cross-section suppression). We also address the efficiency-bandwidth tradeoff and design approximate cloaks with wider bandwidth using a new optimization formulation.
Transfer-matrix calculations of DNA polymer micromechanics under tension and torque constraints
NASA Astrophysics Data System (ADS)
Efremov, Artem K.; Winardhi, Ricksen S.; Yan, Jie
2016-09-01
Recent development of single-molecule manipulation technologies has made it possible to exert constant force and torque on individual DNA biopolymers to probe their elastic characteristics and structural stability. It has been previously shown that depending on the nature of applied mechanical constraints, DNA can exist in several forms including B-, L-, and P-DNA. However, there is still a lack of understanding of how structural heterogeneity of DNA, which may naturally arise due to sequence-dependent DNA properties, protein binding, or DNA damage, influences local stability of the above DNA states. To provide a more complete and detailed description of the DNA mechanics, we developed a theoretical framework based on transfer-matrix calculations and demonstrated how it can be used to predict the DNA behavior upon application of a wide range of force and torque constraints. The resulting phase diagram shows DNA structural transitions that are in good agreement with previous experimental and theoretical studies. We further discuss how the constructed formalism can be extended to include local inhomogeneities in the DNA physical properties, thus making it possible to investigate the effect of DNA sequence as well as protein binding on DNA structural stability.
Transfer matrix modeling of a tensioned piezo-solar hybrid energy harvesting ribbon
NASA Astrophysics Data System (ADS)
Chatterjee, Punnag; Bryant, Matthew
2015-04-01
This paper proposes a multifunctional compliant structure that can harvest electrical power from both incident sunlight and ambient mechanical energy including wind flow or vibration. The energy harvesting device consists of a slender, ribbon-like, flexible thin film solar cell that is laminated with piezoelectric patches. The harvester is mounted in longitudinal tension and subjected to a transverse wind flow to excite flow-induced aeroelastic vibrations. This paper formulates an analytic model of the bending dynamics of the device. We present a Transfer Matrix formulation that also accounts for the changes in natural frequencies and mode shapes of the system when subjected to axial loads in a beam. It also observed that mode shape obtained using TMM formulation shows numerical stability even for very high tensile loads providing results consistent with the geometric boundary conditions applied at the ends of a beam. This article also discusses about structurally modeling a piezo - solar energy harvester using TMM methodology, where a thin clampedclamped solar film is bonded with piezo patches having a much higher bending stiffness. Additionally, the effect of axial tension on the mode shape of the thin host structure of the piezo-solar ribbon is presented and it is shown how this tension can be used advantageously to affect the strain distribution of the entire structure and introduce higher strains at the piezo patches.
Chen, Changming; Niu, Xiaoyan; Han, Chao; Shi, Zuosen; Wang, Xinbin; Sun, Xiaoqiang; Wang, Fei; Cui, Zhanchen; Zhang, Daming
2014-08-25
A transparent reconfigurable optical interleaver module composed of cascaded AWGs-based wavelength-channel-selector/interleaver monolithically integrated with multimode interference (MMI) variable optical attenuators (VOAs) and Mach-Zehnder interferometer (MZI) switch arrays was designed and fabricated using polymer photonic lightwave circuits. Highly fluorinated photopolymer and grafting modified organic-inorganic hybrid material were synthesized as the waveguide core and caldding, respectively. Thermo-optic (TO) tunable wavelength transfer matrix (WTM) function of the module can be achieved for optical routing network. The one-chip transmission loss is ~ 6 dB and crosstalk is less than ~25 dB for transverse-magnetic (TM) mode. The crosstalk and extinction ratio of the MMI VOAs were measured as -15.2 dB and 17.5 dB with driving current 8 mA, respectively. The modulation depth of the TO switches is obtained as ~18.2 dB with 2.2 V bias. Proposed novel interleaver module could be well suited for DWDM optical communication systems.
Transfer matrix computation of critical polynomials for two-dimensional Potts models
Jacobsen, Jesper Lykke; Scullard, Christian R.
2013-02-04
We showed, In our previous work, that critical manifolds of the q-state Potts model can be studied by means of a graph polynomial PB(q, v), henceforth referred to as the critical polynomial. This polynomial may be defined on any periodic two-dimensional lattice. It depends on a finite subgraph B, called the basis, and the manner in which B is tiled to construct the lattice. The real roots v = eK — 1 of PB(q, v) either give the exact critical points for the lattice, or provide approximations that, in principle, can be made arbitrarily accurate by increasing the size ofmore » B in an appropriate way. In earlier work, PB(q, v) was defined by a contraction-deletion identity, similar to that satisfied by the Tutte polynomial. Here, we give a probabilistic definition of PB(q, v), which facilitates its computation, using the transfer matrix, on much larger B than was previously possible.We present results for the critical polynomial on the (4, 82), kagome, and (3, 122) lattices for bases of up to respectively 96, 162, and 243 edges, compared to the limit of 36 edges with contraction-deletion. We discuss in detail the role of the symmetries and the embedding of B. The critical temperatures vc obtained for ferromagnetic (v > 0) Potts models are at least as precise as the best available results from Monte Carlo simulations or series expansions. For instance, with q = 3 we obtain vc(4, 82) = 3.742 489 (4), vc(kagome) = 1.876 459 7 (2), and vc(3, 122) = 5.033 078 49 (4), the precision being comparable or superior to the best simulation results. More generally, we trace the critical manifolds in the real (q, v) plane and discuss the intricate structure of the phase diagram in the antiferromagnetic (v < 0) region.« less
Transfer matrix computation of critical polynomials for two-dimensional Potts models
Jacobsen, Jesper Lykke; Scullard, Christian R.
2013-02-04
We showed, In our previous work, that critical manifolds of the q-state Potts model can be studied by means of a graph polynomial P_{B}(q, v), henceforth referred to as the critical polynomial. This polynomial may be defined on any periodic two-dimensional lattice. It depends on a finite subgraph B, called the basis, and the manner in which B is tiled to construct the lattice. The real roots v = e^{K} — 1 of P_{B}(q, v) either give the exact critical points for the lattice, or provide approximations that, in principle, can be made arbitrarily accurate by increasing the size of B in an appropriate way. In earlier work, P_{B}(q, v) was defined by a contraction-deletion identity, similar to that satisfied by the Tutte polynomial. Here, we give a probabilistic definition of P_{B}(q, v), which facilitates its computation, using the transfer matrix, on much larger B than was previously possible.We present results for the critical polynomial on the (4, 8^{2}), kagome, and (3, 12^{2}) lattices for bases of up to respectively 96, 162, and 243 edges, compared to the limit of 36 edges with contraction-deletion. We discuss in detail the role of the symmetries and the embedding of B. The critical temperatures v_{c }obtained for ferromagnetic (v > 0) Potts models are at least as precise as the best available results from Monte Carlo simulations or series expansions. For instance, with q = 3 we obtain v_{c}(4, 8^{2}) = 3.742 489 (4), v_{c}(kagome) = 1.876 459 7 (2), and v_{c}(3, 12^{2}) = 5.033 078 49 (4), the precision being comparable or superior to the best simulation results. More generally, we trace the critical manifolds in the real (q, v) plane and discuss the intricate structure of the phase diagram in the antiferromagnetic (v < 0) region.
Nilsson, Adam N; Emilsson, Gustav; Nyberg, Lena K; Noble, Charleston; Stadler, Liselott Svensson; Fritzsche, Joachim; Moore, Edward R B; Tegenfeldt, Jonas O; Ambjörnsson, Tobias; Westerlund, Fredrik
2014-09-01
We demonstrate a single DNA molecule optical mapping assay able to resolve a specific Escherichia coli strain from other strains. The assay is based on competitive binding of the fluorescent dye YOYO-1 and the AT-specific antibiotic netropsin. The optical map is visualized by stretching the DNA molecules in nanofluidic channels. We optimize the experimental conditions to obtain reproducible barcodes containing as much information as possible. We implement a multi-ligand transfer matrix method for calculating theoretical barcodes from known DNA sequences. Our method extends previous theoretical approaches for competitive binding of two types of ligands to many types of ligands and introduces a recursive approach that allows long barcodes to be calculated with standard computer floating point formats. The identification of a specific E. coli strain (CCUG 10979) is based on mapping of 50-160 kilobasepair experimental DNA fragments onto the theoretical genome using the developed theory. Our identification protocol introduces two theoretical constructs: a P-value for a best experiment-theory match and an information score threshold. The developed methods provide a novel optical mapping toolbox for identification of bacterial species and strains. The protocol does not require cultivation of bacteria or DNA amplification, which allows for ultra-fast identification of bacterial pathogens.
Transfer Matrix and Reflexion in a Metallo-Dielectric Photonic Crystal
NASA Astrophysics Data System (ADS)
Alejo-Molina, A.; Sánchez-Mondragón, J. J.; Velésquez-Ordoñez, C.; Zamudio-Lara, A.; Escobedo-Alatorre, J. J.; May-Arrioja, D. A.; Torres-Cisneros, M.
2008-04-01
We study the 1D Metallo-Dielectric Photonic Crystal (MDPC) by two alternative methods, the transmittance and the band structure derived from its dispersion relation. Both approaches have well established exponents on two different regimens, Yablonovitch [1] and Maradudin [2]. We discuss, the particular domain where both formalism coexist and become conveniently complementary. We discuss a MDPC created by a DPC with metallic insets. We find that both, metallic and dielectric features coexist at the band structure as well as the transmittance. We point out how they are related, in particular in that regimen where the applicability of [2] is limited, but we can still draw a relation to understand the complex behavior in [1]. We have carried out the analytical and numerical analysis of a one dimensional metallo-dielectric stack as a sequence of extremely thin metallic inlays, periodically spaced, preserving the dielectric cell periodicity, on a substrate of two dielectrics that former themselves a PC.
Transfer-matrix simulations of field emission from bundles of open and closed (5,5) carbon nanotubes
NASA Astrophysics Data System (ADS)
Mayer, A.; Miskovsky, N. M.; Cutler, P. H.; Lambin, Ph.
2003-12-01
We present simulations of field emission from bundles of metallic (5,5) carbon nanotubes, which are either ideally open or closed. The scattering calculations are achieved using a transfer-matrix methodology for consideration of three-dimensional aspects of both the emitting structure and the surface barrier. Band-structure effects are reproduced by using pseudopotentials and enforcing the incident states to first travel through a periodic repetition of the tubes’ basic cell before entering the region containing the fields. The bundles consist of three and six identical structures, which are placed at the corners of equilateral triangles. In all cases, the closed emitters are found to emit less current than the open ones and to be more sensitive to the electric field in their response to neighboring tubes. Due to the enhanced screening of the electric field, the bundles’ emission rates are reduced compared to those of the isolated tubes. It turns out that the rates characterizing bundle and isolated emitters are related by a simple formula, whose dependence on the electric field suggests deviations from the Fowler-Nordheim equation at high fields. Finally, the position of peaks associated with quasilocalized states on top of the closed emitters appears to be a strong indicator of the tubes’ environment.
ABINIT: Plane-Wave-Based Density-Functional Theory on High Performance Computers
NASA Astrophysics Data System (ADS)
Torrent, Marc
2014-03-01
For several years, a continuous effort has been produced to adapt electronic structure codes based on Density-Functional Theory to the future computing architectures. Among these codes, ABINIT is based on a plane-wave description of the wave functions which allows to treat systems of any kind. Porting such a code on petascale architectures pose difficulties related to the many-body nature of the DFT equations. To improve the performances of ABINIT - especially for what concerns standard LDA/GGA ground-state and response-function calculations - several strategies have been followed: A full multi-level parallelisation MPI scheme has been implemented, exploiting all possible levels and distributing both computation and memory. It allows to increase the number of distributed processes and could not be achieved without a strong restructuring of the code. The core algorithm used to solve the eigen problem (``Locally Optimal Blocked Congugate Gradient''), a Blocked-Davidson-like algorithm, is based on a distribution of processes combining plane-waves and bands. In addition to the distributed memory parallelization, a full hybrid scheme has been implemented, using standard shared-memory directives (openMP/openACC) or porting some comsuming code sections to Graphics Processing Units (GPU). As no simple performance model exists, the complexity of use has been increased; the code efficiency strongly depends on the distribution of processes among the numerous levels. ABINIT is able to predict the performances of several process distributions and automatically choose the most favourable one. On the other hand, a big effort has been carried out to analyse the performances of the code on petascale architectures, showing which sections of codes have to be improved; they all are related to Matrix Algebra (diagonalisation, orthogonalisation). The different strategies employed to improve the code scalability will be described. They are based on an exploration of new diagonalization algorithm, as well as the use of external optimized librairies. Part of this work has been supported by the european Prace project (PaRtnership for Advanced Computing in Europe) in the framework of its workpackage 8.
LOBSTER: A tool to extract chemical bonding from plane-wave based DFT.
Maintz, Stefan; Deringer, Volker L; Tchougréeff, Andrei L; Dronskowski, Richard
2016-04-30
The computer program LOBSTER (Local Orbital Basis Suite Towards Electronic-Structure Reconstruction) enables chemical-bonding analysis based on periodic plane-wave (PAW) density-functional theory (DFT) output and is applicable to a wide range of first-principles simulations in solid-state and materials chemistry. LOBSTER incorporates analytic projection routines described previously in this very journal [J. Comput. Chem. 2013, 34, 2557] and offers improved functionality. It calculates, among others, atom-projected densities of states (pDOS), projected crystal orbital Hamilton population (pCOHP) curves, and the recently introduced bond-weighted distribution function (BWDF). The software is offered free-of-charge for non-commercial research. © 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
LOBSTER: A tool to extract chemical bonding from plane-wave based DFT.
Maintz, Stefan; Deringer, Volker L; Tchougréeff, Andrei L; Dronskowski, Richard
2016-04-30
The computer program LOBSTER (Local Orbital Basis Suite Towards Electronic-Structure Reconstruction) enables chemical-bonding analysis based on periodic plane-wave (PAW) density-functional theory (DFT) output and is applicable to a wide range of first-principles simulations in solid-state and materials chemistry. LOBSTER incorporates analytic projection routines described previously in this very journal [J. Comput. Chem. 2013, 34, 2557] and offers improved functionality. It calculates, among others, atom-projected densities of states (pDOS), projected crystal orbital Hamilton population (pCOHP) curves, and the recently introduced bond-weighted distribution function (BWDF). The software is offered free-of-charge for non-commercial research. © 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc. PMID:26914535
NASA Astrophysics Data System (ADS)
Van Hooijdonk, Eloise; Berthier, Serge; Vigneron, Jean-Pol
2012-12-01
Scales of the scarabaeid beetle Hoplia coerulea (Coleoptera) contain fluorescent molecules embedded in a multilayer structure. The consequence of this source confinement is a modification of the fluorescence properties, i.e., an enhancement or inhibition of the emission of certain wavelengths. In this work, we propose a bio-inspired approach to this problem. In other words, we use numerical simulations based on the one-dimensional transfer-matrix formalism to investigate the influence of a Hoplia-like system on emission characteristics and, from the results, we deduce potential technical applications. We reveal that depending on the choice of some parameters (layer thickness, dielectric constant, and position of the emitting source in the structure), it is possible to enhance or inhibit the fluorescence emission for certain wavelengths. This observation could be of great interest to design new optical devices in the field of optoelectronic, solar cells, biosensors, etc.
New method for generating linear transfer matrices through combined rf and solenoid fields
NASA Astrophysics Data System (ADS)
Gulliford, Colwyn; Bazarov, Ivan
2012-02-01
We present a new method for computing the transverse transfer matrix for superimposed axisymmetric rf and solenoid field maps. The algorithm constructs the transfer matrix directly from one-dimensional rf and solenoid field maps without computing numerical derivatives or eigenfunction expansions of the field map data. In addition, this method accurately describes the dynamics of low energy particles starting from a solenoid-immersed cathode, allowing the method to simulate transport through both rf and electrostatic guns. Comparison of particle tracking with the transfer matrix, and direct integration of the equations of motion through several field setups, shows excellent agreement between the two methods.
Student Transfer Matrix, Fall 1992.
ERIC Educational Resources Information Center
Oklahoma State Regents for Higher Education, Oklahoma City.
Comprised primarily of data matrices, this report provides information on students transferring from Oklahoma public and private post-secondary institutions to other public and private post-secondary institutions in the state in fall 1992. The report consists of nine sections. Section I provides an aggregate flow of all students in the state,…
Ganesan, P.; Vanitha, K.; Senthilkumar, L.
2015-08-28
The tunneling current has been calculated by a derived analytical expression for the transmission coefficient (TC) based on the theory of coherent resonant tunneling within the effective mass approximation by applying a constant field in quantum well/dot dopped RTD. For the bare Al{sub 0.35}Ga{sub 0.65}As double barrier structure, the peak to valley ratio is 0.165 from the I-V characteristics. Notably, the presence of In{sub 0.21}Ga{sub 0.79}As well in the emitter region significantly enhances the peak to valley ratio to 0.970. Interestingly, the presence of both the In{sub 0.21}Ga{sub 0.79}As well and InAs QD, increases the peak to valley ratio further to 0.978, because of the greater probability for the energy levels in these regions to be in resonance. On comparing experimental results, which show the similar trend for the current-voltage characteristics, imply that the quantum structure considered here is suitable for device applications.
ERIC Educational Resources Information Center
Pereyra, Pedro; Robledo-Martinez, Arturo
2009-01-01
We explicitly show that the well-known transmission and reflection amplitudes of planar slabs, obtained via an algebraic summation of Fresnel amplitudes, are completely equivalent to those obtained from transfer matrices in the scattering approach. This equivalence makes the finite periodic systems theory a powerful alternative to the cumbersome…
ACRES: An Efficient Method for First-Principles Electronic Structure Calculations of Complex Systems
WAGHMARE,R.V.; KIM,HANCHUL; PARK,I.J.; MODINE,NORMAND A.; MARAGAKIS,P.; KAXIRAS,EFTHIMIOS
2000-08-29
The authors discuss their new implementation of the Adaptive Coordinate Real-space Electronic Structure (ACRES) method for studying the atomic and electronic structure of infinite periodic as well as finite systems, based on density functional theory. This improved version aims at making the method widely applicable and efficient, using high performance Fortran on parallel architectures. The scaling of various parts of an ACRES calculation is analyzed and compared to that of plane-wave based methods. The new developments that lead to enhanced performance, and their parallel implementation, are presented in detail. They illustrate the application of ACRES to the study of elemental crystalline solids, molecules and complex crystalline materials, such as blue bronze and zeolites.
Extension of modified power method to two-dimensional problems
NASA Astrophysics Data System (ADS)
Zhang, Peng; Lee, Hyunsuk; Lee, Deokjung
2016-09-01
In this study, the generalized modified power method was extended to two-dimensional problems. A direct application of the method to two-dimensional problems was shown to be unstable when the number of requested eigenmodes is larger than a certain problem dependent number. The root cause of this instability has been identified as the degeneracy of the transfer matrix. In order to resolve this instability, the number of sub-regions for the transfer matrix was increased to be larger than the number of requested eigenmodes; and a new transfer matrix was introduced accordingly which can be calculated by the least square method. The stability of the new method has been successfully demonstrated with a neutron diffusion eigenvalue problem and the 2D C5G7 benchmark problem.
Analysis of phase shift of surface plasmon polaritons at metallic subwavelength hole arrays
NASA Astrophysics Data System (ADS)
Li, Jiang-Yan; Qiu, Kang-Sheng; Ma, Hai-Qiang
2014-10-01
We present the transmission spectra of light transmitting a metallic thin film perforated with differently shaped subwavelength hole arrays, which are calculated by a plane-wave-based transfer matrix method. We analyze the transmission peak positions and the phase-shift angles of different surface plasmon polariton (SPP) modes by using the microscopic theoretical model proposed by Haitao Liu and Philippe Lalanne [Liu Haitao and Lalanne Philippe 2008 Nature 452 728], in which the phase shift properties of the SPPs scattered by the subwavelength hole arrays are considered. The results show that the transmission peak position and the minus phase shift angle of the SPP increase as the hole size increases. On the other hand, the effective dielectric constant of the metallic film can be deduced by the microscopic theoretical model.
Photonic states deep into the waveguide cutoff frequency of metallic mesh photonic crystal filters
NASA Astrophysics Data System (ADS)
Sang, Hong-Yi; Li, Zhi-Yuan; Gu, Ben-Yuan
2005-02-01
We examine the optical properties of three-dimensional metallic photonic crystals made from a periodic stacking of thin metallic mesh layers separated by homogeneous dielectric films by means of a combination of the plane-wave-based transfer-matrix method and analytical modal solution approach. Although each metallic mesh layer can serve as a frequency-selective surface and involves an intrinsic long-wavelength waveguide cutoff to electromagnetic waves, pass bands and new band gaps can exist far below the cutoff frequency due to the global coupling effect among different mesh layers. The results for the transmission spectra and photonic band structures are in good agreement with existing experimental measurements. It is found that the position of the pass bands and band gaps strongly depends on the thickness and composite of the separation layer between the adjacent metallic mesh layers.
Li, Xiang-Guo; Chu, Iek-Heng; Zhang, X. -G.; Cheng, Hai-Ping
2015-05-28
Electron transport in graphene is along the sheet but junction devices are often made by stacking different sheets together in a “side-contact” geometry which causes the current to flow perpendicular to the sheets within the device. Such geometry presents a challenge to first-principles transport methods. We solve this problem by implementing a plane-wave-based multiple-scattering theory for electron transport. In this study, this implementation improves the computational efficiency over the existing plane-wave transport code, scales better for parallelization over large number of nodes, and does not require the current direction to be along a lattice axis. As a first application, wemore » calculate the tunneling current through a side-contact graphene junction formed by two separate graphene sheets with the edges overlapping each other. We find that transport properties of this junction depend strongly on the AA or AB stacking within the overlapping region as well as the vacuum gap between two graphene sheets. Finally, such transport behaviors are explained in terms of carbon orbital orientation, hybridization, and delocalization as the geometry is varied.« less
Li, Xiang-Guo; Chu, Iek-Heng; Zhang, X. -G.; Cheng, Hai-Ping
2015-05-28
Electron transport in graphene is along the sheet but junction devices are often made by stacking different sheets together in a “side-contact” geometry which causes the current to flow perpendicular to the sheets within the device. Such geometry presents a challenge to first-principles transport methods. We solve this problem by implementing a plane-wave-based multiple-scattering theory for electron transport. In this study, this implementation improves the computational efficiency over the existing plane-wave transport code, scales better for parallelization over large number of nodes, and does not require the current direction to be along a lattice axis. As a first application, we calculate the tunneling current through a side-contact graphene junction formed by two separate graphene sheets with the edges overlapping each other. We find that transport properties of this junction depend strongly on the AA or AB stacking within the overlapping region as well as the vacuum gap between two graphene sheets. Finally, such transport behaviors are explained in terms of carbon orbital orientation, hybridization, and delocalization as the geometry is varied.
A neutron multiplicity analysis method for uranium samples with liquid scintillators
NASA Astrophysics Data System (ADS)
Zhou, Hao; Lin, Hongtao; Liu, Guorong; Li, Jinghuai; Liang, Qinglei; Zhao, Yonggang
2015-10-01
A new neutron multiplicity analysis method for uranium samples with liquid scintillators is introduced. An active well-type fast neutron multiplicity counter has been built, which consists of four BC501A liquid scintillators, a n/γdiscrimination module MPD-4, a multi-stop time to digital convertor MCS6A, and two Am-Li sources. A mathematical model is built to symbolize the detection processes of fission neutrons. Based on this model, equations in the form of R=F*P*Q*T could be achieved, where F indicates the induced fission rate by interrogation sources, P indicates the transfer matrix determined by multiplication process, Q indicates the transfer matrix determined by detection efficiency, T indicates the transfer matrix determined by signal recording process and crosstalk in the counter. Unknown parameters about the item are determined by the solutions of the equations. A 252Cf source and some low enriched uranium items have been measured. The feasibility of the method is proven by its application to the data analysis of the experiments.
Variational methods for field theories
Ben-Menahem, S.
1986-09-01
Four field theory models are studied: Periodic Quantum Electrodynamics (PQED) in (2 + 1) dimensions, free scalar field theory in (1 + 1) dimensions, the Quantum XY model in (1 + 1) dimensions, and the (1 + 1) dimensional Ising model in a transverse magnetic field. The last three parts deal exclusively with variational methods; the PQED part involves mainly the path-integral approach. The PQED calculation results in a better understanding of the connection between electric confinement through monopole screening, and confinement through tunneling between degenerate vacua. This includes a better quantitative agreement for the string tensions in the two approaches. Free field theory is used as a laboratory for a new variational blocking-truncation approximation, in which the high-frequency modes in a block are truncated to wave functions that depend on the slower background modes (Boron-Oppenheimer approximation). This ''adiabatic truncation'' method gives very accurate results for ground-state energy density and correlation functions. Various adiabatic schemes, with one variable kept per site and then two variables per site, are used. For the XY model, several trial wave functions for the ground state are explored, with an emphasis on the periodic Gaussian. A connection is established with the vortex Coulomb gas of the Euclidean path integral approach. The approximations used are taken from the realms of statistical mechanics (mean field approximation, transfer-matrix methods) and of quantum mechanics (iterative blocking schemes). In developing blocking schemes based on continuous variables, problems due to the periodicity of the model were solved. Our results exhibit an order-disorder phase transition. The transfer-matrix method is used to find a good (non-blocking) trial ground state for the Ising model in a transverse magnetic field in (1 + 1) dimensions.
NASA Technical Reports Server (NTRS)
Jara-Almonte, J.; Mitchell, L. D.
1988-01-01
The paper covers two distinct parts: theory and application. The goal of this work was the reduction of model size with an increase in eigenvalue/vector accuracy. This method is ideal for the condensation of large truss- or beam-type structures. The theoretical approach involves the conversion of a continuum transfer matrix beam element into an 'Exact' dynamic stiffness element. This formulation is implemented in a finite element environment. This results in the need to solve a transcendental eigenvalue problem. Once the eigenvalue is determined the eigenvectors can be reconstructed with any desired spatial precision. No discretization limitations are imposed on the reconstruction. The results of such a combined finite element and transfer matrix formulation is a much smaller FEM eigenvalue problem. This formulation has the ability to extract higher eigenvalues as easily and as accurately as lower eigenvalues. Moreover, one can extract many more eigenvalues/vectors from the model than the number of degrees of freedom in the FEM formulation. Typically, the number of eigenvalues accurately extractable via the 'Exact' element method are at least 8 times the number of degrees of freedom. In contrast, the FEM usually extracts one accurate (within 5 percent) eigenvalue for each 3-4 degrees of freedom. The 'Exact' element results in a 20-30 improvement in the number of accurately extractable eigenvalues and eigenvectors.
Zhuo, Ye
2011-01-01
In this thesis, we theoretically study the electromagnetic wave propagation in several passive and active optical components and devices including 2-D photonic crystals, straight and curved waveguides, organic light emitting diodes (OLEDs), and etc. Several optical designs are also presented like organic photovoltaic (OPV) cells and solar concentrators. The first part of the thesis focuses on theoretical investigation. First, the plane-wave-based transfer (scattering) matrix method (TMM) is briefly described with a short review of photonic crystals and other numerical methods to study them (Chapter 1 and 2). Next TMM, the numerical method itself is investigated in details and developed in advance to deal with more complex optical systems. In chapter 3, TMM is extended in curvilinear coordinates to study curved nanoribbon waveguides. The problem of a curved structure is transformed into an equivalent one of a straight structure with spatially dependent tensors of dielectric constant and magnetic permeability. In chapter 4, a new set of localized basis orbitals are introduced to locally represent electromagnetic field in photonic crystals as alternative to planewave basis. The second part of the thesis focuses on the design of optical devices. First, two examples of TMM applications are given. The first example is the design of metal grating structures as replacements of ITO to enhance the optical absorption in OPV cells (chapter 6). The second one is the design of the same structure as above to enhance the light extraction of OLEDs (chapter 7). Next, two design examples by ray tracing method are given, including applying a microlens array to enhance the light extraction of OLEDs (chapter 5) and an all-angle wide-wavelength design of solar concentrator (chapter 8). In summary, this dissertation has extended TMM which makes it capable of treating complex optical systems. Several optical designs by TMM and ray tracing method are also given as a full complement of this
Modelling parallel assemblies of porous materials using the equivalent circuit method.
Pieren, Reto; Heutschi, Kurt
2015-02-01
Recently, the accuracy of the parallel transfer matrix method (P-TMM) and the admittance sum method (ASM) in the prediction of the absorption properties of parallel assemblies of materials was investigated [Verdière, Panneton, Elkoun, Dupont, and Leclaire, J. Acoust. Soc. Am. 136, EL90-EL95 (2014)]. It was demonstrated that P-TMM is more versatile than ASM, as a larger variety of different backing configurations can be handled. Here it will be shown that the same universality is offered by the equivalent circuit method.
NASA Astrophysics Data System (ADS)
Tan, Eng Leong
2005-12-01
This paper presents the recursive algorithm of stiffness matrix method with improved efficiency for computing the total and surface stiffness matrices for a general multilayered anisotropic media. Based on the eigensolutions commonly available for analysis of such media, the recursive algorithm deals with eigen-submatrices directly and bypasses all intermediate layer stiffness submatrices. The improved algorithm obviates the need to compute certain inverse of the original scheme and makes the stiffness matrix recursion more robust. In situation where transfer matrix is numerically stable and easily accessible, an improved recursive algorithm is also given directly in terms of transfer submatrices without involving their explicit inverse.
Variational Methods for Field Theories.
NASA Astrophysics Data System (ADS)
Ben-Menahem, Shahar
The thesis has four parts, dealing with four field theory models: Periodic Quantum Electrodynamics (PQED) in (2 + 1) dimensions, free scalar field theory in (1 + 1) dimensions, the Quantum XY model in (1 + 1) dimensions, and the (1 + 1) dimensional Ising model in a transverse magnetic field. The last three parts deal exclusively with variational methods; the PQED part involves mainly the path-integral approach. The PQED calculation results in a better understanding of the connection between electric confinement through monopole screening, and confinement through tunneling between degenerate vacua. This includes a better quantitative agreement for the string tensions in the two approaches. In the second part, we use free field theory as a loboratory for a new variational blocking-tuncation approximation, in which the high-frequency modes in a block are truncated to wave functions that depend on the slower background modes(Born-Oppenheimer approximation). This "adiabatic truncation" method gives very accurate results for ground -state energy density and correlation functions. Without the adiabatic method, a much larger number of state per block must be kept to get comparable results. Various adiabatic schemes, with one variable kept per site and then two variables per site, are used. For the XY model, several trial wave functions for the ground state are explored, with an emphasis on the periodic Gaussian. A connection is established with the vortex Coulomb gas of the Eclidean path integral approach. The approximations used are taken from the realms of statistical mechanics (mean field approximation, transfer-matrix methods) and of quantum mechanics (iterative blocking schemes). In developing blocking schemes based on continuous variables, problems due to the periodicity of the model were solved. Our results exhibit an order-disorder phase transition. This transition is a rudimentary version of the actual transition known to occur in the XY model, and is
Variational methods for field theories
NASA Astrophysics Data System (ADS)
Ben-Menahem, Shahar
1986-09-01
The thesis is presented in four parts dealing with field theory models: Periodic Quantum Electrodynamics (PQED) in (2+1) dimensions, free scalar field theory in (1+1) dimensions, the Quantum XY model in (1+1) dimensions, and the (1+1) dimensional Ising model in a transverse magnetic field. The last three parts deal exclusively with variational methods; the PQED part involves mainly the path integral approach. The PQED calculation results in a better understanding of the connection between electric confinement through monopole screening, and confinement through tunneling between degenerate vacua. Free field theory is used as a laboratory for a new variational blocking truncation approximation, in which the high frequency modes in a block are truncated to wave functions that depend on the slower background model (Born Oppenheimer approximation). For the XY model, several trial wave functions for the ground state are explored, with an emphasis on the periodic Gaussian. In the 4th part, the transfer matrix method is used to find a good (non blocking) trial ground state for the Ising model in a transverse magnetic field in (1+1) dimensions.
Coherent-Anomaly Method in Critical Phenomena. IV.
NASA Astrophysics Data System (ADS)
Hu, Xiao; Suzuki, Masuo
The systematic Weiss-like and Bethe-like approximations based on the mean-field transfer-matrix method are used to investigate the asymptotic behavior of the induced magnetization on a semi-infinite square lattice, and to investigate the wave-number dependence of the susceptibility in a nonuniform external field. The critical exponents ν, ν', ηi and η are estimated following the general CAM prescription. A new scaling relation ν·ηi=β is obtained in the framework of the finite-degree-of-approximation scaling. Together with previous papers, all the static critical exponents have been estimated by the CAM, and are shown to satisfy the well-known scaling relations.
A study on calculation method for mechanical impedance of air spring
NASA Astrophysics Data System (ADS)
Changgeng, SHUAI; Penghui, LI; Rustighi, Emiliano
2016-09-01
This paper proposes an approximate analytic method of obtaining the mechanical impedance of air spring. The sound pressure distribution in cylindrical air spring is calculated based on the linear air wave theory. The influences of different boundary conditions on the acoustic pressure field distribution in cylindrical air spring are analysed. A 1-order ordinary differential matrix equation for the state vector of revolutionary shells under internal pressure is derived based on the non-moment theory of elastic thin shell. Referring to the transfer matrix method, a kind of expanded homogeneous capacity high precision integration method is introduced to solve the non-homogeneous matrix differential equation. Combined the solved stress field of shell with the calculated sound pressure field in air spring under the displacement harmonic excitation, the approximate analytical expression of the input and transfer mechanical impedance for the air spring can be achieved. The numerical simulation with the Comsol Multiphysics software verifies the correctness of theoretical analysis result.
Constructing parent Hamiltonians for SU(N) ALKT states - a diagrammatic method
NASA Astrophysics Data System (ADS)
Roy, Abhishek; Quella, Thomas
Over the last decade, there has been increasing experimental interest in alkaline cold atom systems which exhibit SU (N) symmmetry. Theoretical work has shown that a one-dimensional SU (N) chain can have N - 1 symmetric protected states distinguished by fractionalized boundary spins. We introduce a new method for constructing SU (N) invariant Hamiltonians for Haldane phases in one dimension. Working at the AKLT point where the ground state is known exactly, we show a universal form of the Hamiltonian for any appropriate choice of physical and boundary spins. We apply our method to the case where the physical spin is in the adjoint representation and obtain a general expression for the Hamiltonian as well the Transfer Matrix for any N. Finally we comment on the relevance of our results to the generalized Haldane conjecture.
A new process to estimate the speed of sound using three-sensor method
NASA Astrophysics Data System (ADS)
Simon, Alexandre; Martinez-Molina, John-Jairo; Fortes-Patella, Regiane
2016-01-01
As a part of complex works aiming at the evaluation of the pump's dynamic transfer matrix, this paper presents an estimation method of the speed of sound in water and water/air flows using three pressure transducer measurements. The experimental study was carried out at the CREMHyG acoustic test rig, for a void ratio varying from 0 to 1 % and for amplitudes of speed of sound from 100 to 1400 m/s. To estimate the speed of sound in this large range of amplitude, a new post-treatment approach was developed, based on the least mean squares method. Experimental results obtained were compared with existing theoretical models, and a very good agreement was observed. The post-processing appeared fast, robust and accurate for all the mono- and diphasic flows analyzed. The results presented in this paper can be applied, for instance, in acoustic characterization of the hydraulic systems, mainly in the case of space rocket turbopump applications.
Saha, Krishnendu; Straus, Kenneth J.; Glick, Stephen J.; Chen, Yu.
2014-08-28
To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.
NASA Astrophysics Data System (ADS)
Saha, Krishnendu; Straus, Kenneth J.; Chen, Yu.; Glick, Stephen J.
2014-08-01
To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.
Transfer Matrix Approach to 1d Random Band Matrices: Density of States
NASA Astrophysics Data System (ADS)
Shcherbina, Mariya; Shcherbina, Tatyana
2016-08-01
We study the special case of n× n 1D Gaussian Hermitian random band matrices, when the covariance of the elements is determined by the matrix J=(-W^2triangle +1)^{-1} . Assuming that n≥ CW log W≫ 1 , we prove that the averaged density of states coincides with the Wigner semicircle law up to the correction of order W^{-1}.
Transfer Matrix Approach to 1d Random Band Matrices: Density of States
NASA Astrophysics Data System (ADS)
Shcherbina, Mariya; Shcherbina, Tatyana
2016-09-01
We study the special case of n× n 1D Gaussian Hermitian random band matrices, when the covariance of the elements is determined by the matrix J=(-W^2triangle +1)^{-1}. Assuming that n≥ CW log W≫ 1, we prove that the averaged density of states coincides with the Wigner semicircle law up to the correction of order W^{-1}.
Mazauric, Serge; Hébert, Mathieu; Simonot, Lionel; Fournel, Thierry
2014-12-01
We introduce a model allowing convenient calculation of the spectral reflectance and transmittance of duplex prints. It is based on flux transfer matrices and enables retrieving classical Kubelka-Munk formulas, as well as extended formulas for nonsymmetric layers. By making different assumptions on the flux transfers, we obtain two predictive models for the duplex halftone prints: the "duplex Clapper-Yule model," which is an extension of the classical Clapper-Yule model, and the "duplex primary reflectance-transmittance model." The two models can be calibrated from either reflectance or transmittance measurements; only the second model can be calibrated from both measurements, thus giving optimal accuracy for both reflectance and transmittance predictions. The conceptual differences between the two models are deeply analyzed, as well as their advantages and drawbacks in terms of calibration. According to the test carried out in this study with paper printed in inkjet, their predictive performances are good provided appropriate calibration options are selected.
Saha, Krishnendu; Straus, Kenneth J; Chen, Yu; Glick, Stephen J
2014-08-28
To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.
An Exact Transfer Matrix Formulation of Plane Sound Wave Transmission in Inhomogeneous Ducts
NASA Astrophysics Data System (ADS)
Dockumaci, E.
1998-11-01
The impedance, or the reflection coefficient, of plane sound waves in inhomogeneous ducts satisfies a Riccati equation. The present paper shows that the duct impedance matrix, or the scattering matrix, can be related explicitly to the solutions of the associated linear equation of the Riccati equation for duct impedance, or reflection coefficient, respectively. New exact analytical scattering matrix solutions, which follow as consequences of this connection, are given for two significant duct acoustics problems, namely, the sound transmission in non-uniform ducts carrying an incompressible subsonic low Mach number mean flow transmission of sound in uniform ducts with a full quadratic axial mean temperature gradient.
NASA Astrophysics Data System (ADS)
Geng, Litao; Ren, Ruibo; Zhong, Yang; Xu, Qian
2011-02-01
The asphalt pavement is regarded as a multilayered elastic half space axisymmetrical body. By introducing the relationship between material characteristics and temperature into the fundamental equations of thermoelasticity and using mathematic methods of Laplace and Hankel integral transformation, the stiffness matrix for a layer is derived firstly. Then the global stiffness matrix is established for multilayered elastic half space using the finite element concepts in which layers are completely contacted. Therefore, explicit solution for thermal stresses of the asphalt pavement is obtained from the solution of the algebra equation formed by global stiffness matrix and the inverse Hankel and Laplace integral transformation. Because the elements of matrix do not include positive exponential function, the calculation is not overflowed and the shortages of transfer matrix method are overcome. This approach serves as a better model for real pavement structure as it takes into account the relationships between the material characteristics and temperature in the pavement system.
NASA Astrophysics Data System (ADS)
Voityuk, Alexander A.; Rösch, Notker
2002-09-01
The purpose of this communication is two-fold. We introduce the fragment charge difference (FCD) method to estimate the electron transfer matrix element HDA between a donor D and an acceptor A, and we apply this method to several aspects of hole transfer electronic couplings in π-stacks of DNA, including systems with several donor-acceptor sites. Within the two-state model, our scheme can be simplified to recover a convenient estimate of the electron transfer matrix element HDA=(1-Δq2)1/2(E2-E1)/2 based on the vertical excitation energy E2-E1 and the charge difference Δq between donor and acceptor. For systems with strong charge separation, Δq≳0.95, one should resort to the FCD method. As favorable feature, we demonstrate the stability of the FCD approach for systems which require an approach beyond the two-state model. On the basis of ab initio calculations of various DNA related systems, we compared three approaches for estimating the electronic coupling: the minimum splitting method, the generalized Mulliken-Hush (GMH) scheme, and the FCD approach. We studied the sensitivity of FCD and GMH couplings to the donor-acceptor energy gap and found both schemes to be quite robust; they are applicable also in cases where donor and acceptor states are off resonance. In the application to π-stacks of DNA, we demonstrated for the Watson-Crick pair dimer [(GC),(GC)] how structural changes considerably affect the coupling strength of electron hole transfer. For models of three Watson-Crick pairs, we showed that the two-state model significantly overestimates the hole transfer coupling whereas simultaneous treatment of several states leads to satisfactory results.
NASA Astrophysics Data System (ADS)
Jiang, Mingfeng; Xia, Ling; Shou, Guofa; Tang, Min
2007-03-01
Computing epicardial potentials from body surface potentials constitutes one form of ill-posed inverse problem of electrocardiography (ECG). To solve this ECG inverse problem, the Tikhonov regularization and truncated singular-value decomposition (TSVD) methods have been commonly used to overcome the ill-posed property by imposing constraints on the magnitudes or derivatives of the computed epicardial potentials. Such direct regularization methods, however, are impractical when the transfer matrix is large. The least-squares QR (LSQR) method, one of the iterative regularization methods based on Lanczos bidiagonalization and QR factorization, has been shown to be numerically more reliable in various circumstances than the other methods considered. This LSQR method, however, to our knowledge, has not been introduced and investigated for the ECG inverse problem. In this paper, the regularization properties of the Krylov subspace iterative method of LSQR for solving the ECG inverse problem were investigated. Due to the 'semi-convergence' property of the LSQR method, the L-curve method was used to determine the stopping iteration number. The performance of the LSQR method for solving the ECG inverse problem was also evaluated based on a realistic heart-torso model simulation protocol. The results show that the inverse solutions recovered by the LSQR method were more accurate than those recovered by the Tikhonov and TSVD methods. In addition, by combing the LSQR with genetic algorithms (GA), the performance can be improved further. It suggests that their combination may provide a good scheme for solving the ECG inverse problem.
Matrix methods applied to acoustic waves in multilayers
NASA Astrophysics Data System (ADS)
Adler, Eric L.
1990-11-01
Matrix methods for analyzing the electroacoustic characteristics of anisotropic piezoelectric multilayers are described. The conceptual usefulness of the methods is demonstrated in a tutorial fashion by examples showing how formal statements of propagation, transduction, and boundary-value problems in complicated acoustic layered geometries such as those which occur in surface acoustic wave (SAW) devices, in multicomponent laminates, and in bulk-wave composite transducers are simplified. The formulation given reduces the electroacoustic equations to a set of first-order matrix differential equations, one for each layer, in the variables that must be continuous across interfaces. The solution to these equations is a transfer matrix that maps the variables from one layer face to the other. Interface boundary conditions for a planar multilayer are automatically satisfied by multiplying the individual transfer matrices in the appropriate order, thus reducing the problem to just having to impose boundary conditions appropriate to the remaining two surfaces. The computational advantages of the matrix method result from the fact that the problem rank is independent of the number of layers, and from the availability of personal computer software that makes interactive numerical experimentation with complex layered structures practical.
Guo, Dagang; Lin, Rongming; Wang, Weijun
2005-08-01
A generalized study has been carried out on the modeling of a Fabry-Perot microcavity for sensing applications. Different analytical models on transmission characteristics of a Fabry-Perot microcavity are established by using plane-wave-based techniques, such as the Macleod characteristic matrix technique, the transfer matrix technique, and Smith's technique. A novel Gaussian-optics-based model for a Fabry-Perot microcavity illuminated by a laser beam is then developed and validated. The influence of laser beam waist on microcavity optical response is investigated, and the required minimal beam waist size is explored to ensure a useful optical response for sensing applications that can be accurately predicted by plane-wave optics. Also, the perturbations of microcavity performance induced by different types of microcavity mirror imperfections are discussed, based on the novel optical model. The prototype of the proposed Fabry-Perot microcavity for sensing applications has been successfully fabricated and characterized.
A METHOD TO MEASURE THE FOCUSING PROPERTIES (R-MATRIX) OF A MAGNET.
TSOUPAS,N.THIEBERGER,P.BROWN,K.GASSNER,D.GLENN,W.AHRENS,L.ROSER,T.LEE,Y.Y.WEI,J.
2004-07-05
In this paper we discuss, and study the feasibility of a method that may be used to measure the focusing properties of a magnet. This method may prove valuable when applied to ''non-conventional'' magnets that deviate from the usual dipole magnets or other multipole magnets (quadrupoles/sextupoles etc.) which are commonly used in a synchrotron or a beam line. In this category of ''non-conventional'' magnets, fall special magnets, which come under the name ''Snakes'', which are being used in synchrotron accelerators to introduce artificial spin resonances to help overcome the intrinsic and/or imperfection spin resonances which appear during the acceleration of polarized beams. This method of measuring the focusing properties of a magnet requires the use of ''low energy'' and ''high rigidity'' heavy-ions which may be obtained from the BNL Tandem accelerator. In brief the method consists on, injecting ''narrow-beamlets'' of heavy ions into a magnet and measuring the coordinates, of these ''narrow-beamlets'', at the entrance and exit of the magnet. From the measurement of the coordinates of the ''narrow-beamlets'' we can deduce information on the R matrix (first order transfer matrix elements) and higher order matrix elements that define the focusing properties of the magnet.
NASA Astrophysics Data System (ADS)
Deng, X. D.; Monnier, T.; Guy, P.; Courbon, J.
2013-06-01
Acoustic microscopy of multilayered media as well as functionally graded coatings on substrate necessitates to model acoustic wave propagation in such materials. In particular, we chose to use Stroh formalism and the recursive stiffness matrix method to obtain the reflection coefficient of acoustic waves on these systems because this allows us to address the numerical instability of the conventional transfer matrix method. In addition, remarkable simplification and computational efficiency are obtained. We proposed a modified formulation of the angular spectrum of the transducer based on the theoretical analysis of a line-focus transducer for broadband acoustic microscopy. A thermally sprayed coating on substrate is treated as a functionally graded material along the depth of the coating and is approximately represented by a number of homogeneous elastic layers with exponentially graded elastic properties. The agreement between our experimental and numerical analyses on such thermal sprayed coatings with different thicknesses confirms the efficiency of the method. We proved the ability of the inversion procedure to independently determine both thickness and gradient of elastic properties. The perspective of this work is the opportunity to non-destructively measure these features in functionally graded materials.
NASA Astrophysics Data System (ADS)
Batta, Gy.; Kövér, K. E.; Kowalewski, J.
1999-01-01
Conventional and enhanced 1D experiments and different NOESY experiments (the 2D unbiased method) were performed for measuring CSA/DD cross-correlated relaxation on trehalose, a compound which could be approximated as a spherical top, and on simple model compounds comprisingC3vsymmetry (CHCl3, triphenylsilane (TPSi)). The comparison gives experimental evidence for the equivalence of the methods within the limits of the two-spin approach. 1D data are evaluated with both the simple initial rate and the Redfield relaxation matrix approach. The 2D data are obtained from the so-called transfer matrix using the Perrin-Gipe eigenvalue/eigenvector method. For the improved performance of the 2D method, anX-filtered (HHH) NOESY is suggested at the natural abundance of13C (or other dilute, low γ species). Also, experimental parameters crucial for reliable CSA data are tested (e.g., the impact of insufficient relaxation delay). Error estimation is carried out for fair comparison of methods. Revised liquid state1H and13C (29Si) CSA data are presented for chloroform and TPSi.
NASA Astrophysics Data System (ADS)
Briones-Torres, J. A.; Pernas-Salomón, R.; Pérez-Álvarez, R.; Rodríguez-Vargas, I.
2016-05-01
Gapless bilayer graphene (GBG), like monolayer graphene, is a material system with unique properties, such as anti-Klein tunneling and intrinsic Fano resonances. These properties rely on the gapless parabolic dispersion relation and the chiral nature of bilayer graphene electrons. In addition, propagating and evanescent electron states coexist inherently in this material, giving rise to these exotic properties. In this sense, bilayer graphene is unique, since in most material systems in which Fano resonance phenomena are manifested an external source that provides extended states is required. However, from a numerical standpoint, the presence of evanescent-divergent states in the eigenfunctions linear superposition representing the Dirac spinors, leads to a numerical degradation (the so called Ωd problem) in the practical applications of the standard Coefficient Transfer Matrix (K) method used to study charge transport properties in Bilayer Graphene based multi-barrier systems. We present here a straightforward procedure based in the hybrid compliance-stiffness matrix method (H) that can overcome this numerical degradation. Our results show that in contrast to standard matrix method, the proposed H method is suitable to study the transmission and transport properties of electrons in GBG superlattice since it remains numerically stable regardless the size of the superlattice and the range of values taken by the input parameters: the energy and angle of the incident electrons, the barrier height and the thickness and number of barriers. We show that the matrix determinant can be used as a test of the numerical accuracy in real calculations.
Accurate reliability analysis method for quantum-dot cellular automata circuits
NASA Astrophysics Data System (ADS)
Cui, Huanqing; Cai, Li; Wang, Sen; Liu, Xiaoqiang; Yang, Xiaokuo
2015-10-01
Probabilistic transfer matrix (PTM) is a widely used model in the reliability research of circuits. However, PTM model cannot reflect the impact of input signals on reliability, so it does not completely conform to the mechanism of the novel field-coupled nanoelectronic device which is called quantum-dot cellular automata (QCA). It is difficult to get accurate results when PTM model is used to analyze the reliability of QCA circuits. To solve this problem, we present the fault tree models of QCA fundamental devices according to different input signals. After that, the binary decision diagram (BDD) is used to quantitatively investigate the reliability of two QCA XOR gates depending on the presented models. By employing the fault tree models, the impact of input signals on reliability can be identified clearly and the crucial components of a circuit can be found out precisely based on the importance values (IVs) of components. So this method is contributive to the construction of reliable QCA circuits.
Research on FBG-based longitudinal-acousto-optic modulator with Fourier mode coupling method.
Li, Zhuoxuan; Pei, Li; Liu, Chao; Ning, Tigang; Yu, Shaowei
2012-10-20
Fourier mode coupling model was first applied to achieve the spectra property of a fiber Bragg grating (FBG)-based longitudinal-acousto-optic modulator. Compared with traditional analysis algorithms, such as the transfer matrix method, the Fourier mode coupling model could improve the computing efficiency up to 100 times with a guarantee of accuracy. In this paper, based on the theoretical analysis of this model, the spectra characteristics of the modulator in different frequencies and acoustically induced strains were numerically simulated. In the experiment, a uniform FBG was modulated by acoustic wave (AW) at 12 different frequencies. In particular, the modulator responses at 563 and 885.5 KHz with three different lead zirconate titanate (PZT) loads applied were plotted for illustration, and the linear fitting of experimental data demonstrated a good match with the simulation result. The acoustic excitation of the longitudinal wave is obtained using a conic silica horn attached to the surface of a shear-mode PZT plate paralleled to the fiber axis. This way of generating longitudinal AW with a transversal PZT may shed light on the optimal structural design for the FBG-based longitudinal-acousto-optic modulator.
Electrical investigations of hybrid OLED microcavity structures with novel encapsulation methods
NASA Astrophysics Data System (ADS)
Meister, Stefan; Brückner, Robert; Fröb, Hartmut; Leo, Karl
2016-04-01
An electrical driven organic solid state laser is a very challenging goal which is so far well beyond reach. As a step towards realization, we monolithically implemented an Organic Light Emitting Diode (OLED) into a dielectric, high quality microcavity (MC) consisting of two Distributed Bragg Reectors (DBR). In order to account for an optimal optical operation, the OLED structure has to be adapted. Furthermore, we aim to excite the device not only electrically but optically as well. Different OLED structures with an emission layer consisting of Alq3:DCM (2 wt%) were investigated. The External Quantum Efficiencies (EQE) of this hybrid structures are in the range of 1-2 %, as expected for this material combination. Including metal layers into a MC is complicated and has a huge impact on the device performance. Using Transfer-Matrix-Algorithm (TMA) simulations, the best positions for the metal electrodes are determined. First, the electroluminescence (EL) of the adjusted OLED structure on top of a DBR is measured under nitrogen atmosphere. The modes showed quality factors of Q = 60. After the deposition of the top DBR, the EL is measured again and the quality factors increased up to Q = 600. Considering the two 25-nm-thick-silver contacts a Q-factor of 600 is very high. The realization of a suitable encapsulation method is important. Two approaches were successfully tested. The first method is based on the substitution of a DBR layer with a layer produced via Atomic Layer Deposition (ALD). The second method uses a 0.15-mm-thick cover glass glued on top of the DBR with a 0.23-μm-thick single-component glue layer. Due to the working encapsulation, it is possible to investigate the sample under ambient conditions.
Yang, Chao
2009-07-17
We present a practical approach to calculate the complex band structure of an electrode for quantum transport calculations. This method is designed for plane wave based Hamiltonian with nonlocal pseudopotentials and the auxiliary periodic boundary condition transport calculation approach. Currently there is no direct method to calculate all the evanescent states for a given energy for systems with nonlocal pseudopotentials. On the other hand, in the auxiliary periodic boundary condition transport calculation, there is no need for all the evanescent states at a given energy. The current method fills this niche. The method has been used to study copper and gold nanowires and bulk electrodes.
A Method for Efficient Transmittance Spectrum Prediction of Transparent Composite Electrodes
NASA Astrophysics Data System (ADS)
Zhao, Zhao; Dhar, A.; Alford, T. L.
2015-07-01
The interest in indium-free transparent composite electrode (TCE), a thin metal layer embedded between two transparent metal oxide (TMO) layers resulting in TMO/metal/TMO composite structure, has grown recently with the advent of their high figures of merit and its potential application in photovoltaic applications. However, most of the work to date has focused on experimentally producing the best optically transmitting TCE. To better design TCEs and minimize experimental work, it would be useful to develop a model that predicts the optical transmission. In the current work, the transfer-matrix method is employed to calculate the transmittance spectrum of TCE. To validate this approach, the transmittance spectra of TiO2/Au/TiO2 and TiO2/Ag/TiO2 multilayer thin-film TCEs are calculated with use of extracted material parameters. The calculated transmittance spectrum of TiO2/Au/TiO2 matches the measured spectrum quite well. However, the calcualted transmittance of TiO2/Ag/TiO2 is higher than its measured transmittance. The presence of voids in the Ag film is probably responsible for the decreased transmittance of the TiO2/Ag/TiO2 sample, and the continuous Au film in TiO2/Au/TiO2 ensures a good agreement between transmittance prediction and measurement. Our approach is a reliable tool to predict the optical transmittance of TCE with continuous films, and it can efficiently expedite the selection from numerous possible combinations of transparent metal oxides and metals when developing TCEs for future photovoltaic applications. It can also serve as a convenient method to assess the continuity of embedded metal layer.
An MR image-guided, voxel-based partial volume correction method for PET images
Wang, Hesheng; Fei, Baowei
2012-01-01
Purpose: Partial volume effect in positron emission tomography (PET) can cause incorrect quantification of radiopharmaceutical uptake in functional imaging. A PET partial volume correction method is presented to attenuate partial volume blurring and to yield voxel-based corrected PET images. Methods: By modeling partial volume effect as a convolution of point spread function of the PET scanner, the reconstructed PET images are corrected by iterative deconvolution with an edge-preserving smoothness constraint. The constraint is constructed to restore discontinuities extracted from coregistered MR images but maintains the smoothness in radioactivity distribution. The correction is implemented in a Bayesian deconvolution framework and is solved by a conjugate gradient method. The performance of the method was compared with the geometric transfer matrix (GTM) method on a simulated dataset. The method was evaluated on synthesized brain FDG–PET data and phantom MRI–PET experiments. Results: The true PET activity of objects with a size of greater than the full-width at half maximum of the point spread function has been effectively restored in the simulated data. The partial volume correction method is quantitatively comparable to the GTM method. For synthesized FDG–PET with true activity 0 μci/cc for cerebrospinal fluid (CSF), 228 μci/cc for white matter (WM), and 621 μci/cc for gray matter (GM), the method has improved the radioactivity quantification from 186 ± 16 μci/cc to 30 ± 7 μci/cc in CSF, 317 ± 15 μci/cc to 236 ± 10 μci/cc for WM, 438 ± 4 μci/cc to 592 ± 5 μci/cc for GM. Both visual and quantitative assessments show improvement of partial volume correction in the synthesized and phantom experiments. Conclusions: The partial volume correction method improves the quantification of PET images. The method is comparable to the GTM method but does not need MR image segmentation or prior tracer distribution information. The
Cui, Jiwen; Feng, Kunpeng; Hu, Yang; Li, Junying; Dang, Hong; Tan, Jiubin
2015-12-28
Focusing on the ultra-precision dimensional measurement of parts with micro-scale dimensions and high aspect ratios, a two-dimensional double fiber probe with a single fiber Bragg grating (DS-FBG probe) is investigated in detail in this paper. The theoretical analysis of the sensing principle is verified by spectrum simulations of the DS-FBG probe with a modified transfer matrix method using the strain distribution within the DS-FBG probe. The fabrication process and physical principle of the capillary-driven self-assembly of double fibers in the UV adhesive with a low viscosity are demonstrated. Experimental results indicate that resolutions of 30 nm in radial direction and 15 nm in axial direction can be achieved, and the short-term displacement drifts within 90 seconds are 28.0 nm in radial direction and 7.9 nm in axial direction, and the long-term displacement drifts within 1 hour are 61.3 nm in radial direction and 17.3 nm in axial direction. The repeatability of the probing system can reach 60 nm and the measurement result of a standard nozzle is 300.49 μm with a standard deviation of 20 nm. PMID:26831960
Greve, Douglas N; Salat, David H; Bowen, Spencer L; Izquierdo-Garcia, David; Schultz, Aaron P; Catana, Ciprian; Becker, J Alex; Svarer, Claus; Knudsen, Gitte M; Sperling, Reisa A; Johnson, Keith A
2016-05-15
A cross-sectional group study of the effects of aging on brain metabolism as measured with (18)F-FDG-PET was performed using several different partial volume correction (PVC) methods: no correction (NoPVC), Meltzer (MZ), Müller-Gärtner (MG), and the symmetric geometric transfer matrix (SGTM) using 99 subjects aged 65-87years from the Harvard Aging Brain study. Sensitivity to parameter selection was tested for MZ and MG. The various methods and parameter settings resulted in an extremely wide range of conclusions as to the effects of age on metabolism, from almost no changes to virtually all of cortical regions showing a decrease with age. Simulations showed that NoPVC had significant bias that made the age effect on metabolism appear to be much larger and more significant than it is. MZ was found to be the same as NoPVC for liberal brain masks; for conservative brain masks, MZ showed few areas correlated with age. MG and SGTM were found to be similar; however, MG was sensitive to a thresholding parameter that can result in data loss. CSF uptake was surprisingly high at about 15% of that in gray matter. The exclusion of CSF from SGTM and MG models, which is almost universally done, caused a substantial loss in the power to detect age-related changes. This diversity of results reflects the literature on the metabolism of aging and suggests that extreme care should be taken when applying PVC or interpreting results that have been corrected for partial volume effects. Using the SGTM, significant age-related changes of about 7% per decade were found in frontal and cingulate cortices as well as primary visual and insular cortices. PMID:26915497
Chorin, A.J. |
1993-06-01
Vortex methods originated from the observation that in incompressible inviscid flow vorticity (or, more accurately, circulation) is a conserved quantity, as can be readily deduced from the absence of tangential stresses. Thus, if the vorticity is known at time t=0, one can find the flow at a later time by simply following the vorticity. In this narrow context, a vortex method is a numerical method that follows vorticity. The author restricts himself in these lectures to a special class of numerical vortex methods, those that are based on a Lagrangian transport of vorticity in hydrodynamics by smoothed particles (blobs) and those whose analysis contributes to the understanding of blob methods. Blob methods started in the 1930`s.
Technology Transfer Automated Retrieval System (TEKTRAN)
Resistivity methods were among the first geophysical techniques developed. The basic concept originated with Conrad Schlumberger, who conducted the initial resistivity field tests in Normandy, France during 1912. The resistivity method, employed in its earliest and most conventional form, uses an ex...
Lin, YuPo J.; Hestekin, Jamie; Arora, Michelle; St. Martin, Edward J.
2004-09-28
An electrodeionization method for continuously producing and or separating and/or concentrating ionizable organics present in dilute concentrations in an ionic solution while controlling the pH to within one to one-half pH unit method for continuously producing and or separating and/or concentrating ionizable organics present in dilute concentrations in an ionic solution while controlling the pH to within one to one-half pH unit.
Omlor, G W; Bertram, H; Kleinschmidt, K; Fischer, J; Brohm, K; Guehring, T; Anton, M; Richter, Wiltrud
2010-04-01
Intervertebral disc (IVD) degeneration involves a series of biochemical and morphological changes leading to loss of spinal stability and flexibility. Cell therapy is promising to reconstitute IVDs with new cells, however, sustained metabolic activity seems crucial for an active contribution to regeneration. The aim of the present study was to establish methods for separate follow up of persistence and activity of autologous porcine mesenchymal stem cells (pMSC) after implantation into IVDs of Goettingen minipigs in vivo in order to conclude about the potential of such an intervention strategy. For quantitative follow up, the transfer matrix was supplemented with Al(2)O(3) particles and pMSC which were retrovirally labeled with firefly luciferase (pMSC-Luc). Six mature Goettingen minipigs underwent matrix based cell transfer after partial nucleotomy of lumbar IVDs (n = 24). Day 0 and day 3 segments were analyzed for retained volume of Al(2)O(3) particles by micro-computed-tomography (muCT) and for cell activity by luciferase enzyme assessment. Three days after injection a reduction of Al(2)O(3) particles (P = 0.028) to about 9% and of pMSC-Luc activity to about 7% of initial values (P = 0.003) was detected, which suggests loss of 90% of the implant material under in vivo conditions without evidence for reduced pMSC-Luc metabolic activity (P = 0.887). In conclusion, separate follow up of implant material and cell activity was possible and unravels problems with in vivo implant persistence after annular puncture rather than quick loss of cell activity. Therefore, IVD-regeneration-strategies should increasingly focus on annulus reconstruction in order to reduce implant loss due to annular failure.
NASA Astrophysics Data System (ADS)
Re, Matteo; Valentini, Giorgio
2012-03-01
Ensemble methods are statistical and computational learning procedures reminiscent of the human social learning behavior of seeking several opinions before making any crucial decision. The idea of combining the opinions of different "experts" to obtain an overall “ensemble” decision is rooted in our culture at least from the classical age of ancient Greece, and it has been formalized during the Enlightenment with the Condorcet Jury Theorem[45]), which proved that the judgment of a committee is superior to those of individuals, provided the individuals have reasonable competence. Ensembles are sets of learning machines that combine in some way their decisions, or their learning algorithms, or different views of data, or other specific characteristics to obtain more reliable and more accurate predictions in supervised and unsupervised learning problems [48,116]. A simple example is represented by the majority vote ensemble, by which the decisions of different learning machines are combined, and the class that receives the majority of “votes” (i.e., the class predicted by the majority of the learning machines) is the class predicted by the overall ensemble [158]. In the literature, a plethora of terms other than ensembles has been used, such as fusion, combination, aggregation, and committee, to indicate sets of learning machines that work together to solve a machine learning problem [19,40,56,66,99,108,123], but in this chapter we maintain the term ensemble in its widest meaning, in order to include the whole range of combination methods. Nowadays, ensemble methods represent one of the main current research lines in machine learning [48,116], and the interest of the research community on ensemble methods is witnessed by conferences and workshops specifically devoted to ensembles, first of all the multiple classifier systems (MCS) conference organized by Roli, Kittler, Windeatt, and other researchers of this area [14,62,85,149,173]. Several theories have been
NASA Astrophysics Data System (ADS)
Re, Matteo; Valentini, Giorgio
2012-03-01
Ensemble methods are statistical and computational learning procedures reminiscent of the human social learning behavior of seeking several opinions before making any crucial decision. The idea of combining the opinions of different "experts" to obtain an overall “ensemble” decision is rooted in our culture at least from the classical age of ancient Greece, and it has been formalized during the Enlightenment with the Condorcet Jury Theorem[45]), which proved that the judgment of a committee is superior to those of individuals, provided the individuals have reasonable competence. Ensembles are sets of learning machines that combine in some way their decisions, or their learning algorithms, or different views of data, or other specific characteristics to obtain more reliable and more accurate predictions in supervised and unsupervised learning problems [48,116]. A simple example is represented by the majority vote ensemble, by which the decisions of different learning machines are combined, and the class that receives the majority of “votes” (i.e., the class predicted by the majority of the learning machines) is the class predicted by the overall ensemble [158]. In the literature, a plethora of terms other than ensembles has been used, such as fusion, combination, aggregation, and committee, to indicate sets of learning machines that work together to solve a machine learning problem [19,40,56,66,99,108,123], but in this chapter we maintain the term ensemble in its widest meaning, in order to include the whole range of combination methods. Nowadays, ensemble methods represent one of the main current research lines in machine learning [48,116], and the interest of the research community on ensemble methods is witnessed by conferences and workshops specifically devoted to ensembles, first of all the multiple classifier systems (MCS) conference organized by Roli, Kittler, Windeatt, and other researchers of this area [14,62,85,149,173]. Several theories have been
Duval, J.S.
1980-01-01
Radioactivity measurements have played an important role in geophysics since about 1935, and they have increased in importance to the present. The most important areas of application have been in petroleum and uranium exploration. Radioactivity measurements have proved useful in geologic mapping, as well as in specialized applications such as reactor-site monitoring. The technological development of the method has reached a plateau, and the future of the method for some applications will depend upon development of more sophisticated data processing and interpretation. -Author
Glass, J.T.
1993-01-01
Methods discussed in this compilation of notes and diagrams are Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and other surface analysis techniques (auger electron spectroscopy, x-ray photoelectron spectroscopy, electron energy loss spectroscopy, and scanning tunnelling microscopy). A comparative evaluation of different techniques is performed. In-vacuo and in-situ analyses are described.
Townsend, R.G.
1959-08-25
A method is described for protectively coating beryllium metal by etching the metal in an acid bath, immersing the etched beryllium in a solution of sodium zincate for a brief period of time, immersing the beryllium in concentrated nitric acid, immersing the beryhlium in a second solution of sodium zincate, electroplating a thin layer of copper over the beryllium, and finally electroplating a layer of chromium over the copper layer.
Googin, J.M.
1963-11-01
Methods of making articles by powder metallurgy techniques are presented. An article is made by packing a metal powder into a desired shape, raising the temperature of the powder compact to a sintering temperature in the presence of a reducing gas, and alternately increasing and decreasing the pressure of the gas while the temperatume is being raised. The product has a greater density than can be achieved by sintering for the same length of time at a constant gas pressure. (AEC)
Walls, Claudia A.; Kirby, Glen H.; Janney, Mark A.; Omatete, Ogbemi O.; Nunn, Stephen D.; McMillan, April D.
2000-01-01
A method of gelcasting includes the steps of providing a solution of at least hydroxymethylacrylamide (HMAM) and water. At least one inorganic powder is added to the mixture. At least one initiator system is provided to polymerize the HMAM. The initiator polymerizes the HMAM and water, to form a firm hydrogel that contains the inorganic powder. One or more comonomers can be polymerized with the HMAM monomer, to alter the final properties of the gelcast material. Additionally, one or more additives can be included in the polymerization mixture, to alter the properties of the gelcast material.
Gini, Giuseppina
2016-01-01
In this chapter, we introduce the basis of computational chemistry and discuss how computational methods have been extended to some biological properties and toxicology, in particular. Since about 20 years, chemical experimentation is more and more replaced by modeling and virtual experimentation, using a large core of mathematics, chemistry, physics, and algorithms. Then we see how animal experiments, aimed at providing a standardized result about a biological property, can be mimicked by new in silico methods. Our emphasis here is on toxicology and on predicting properties through chemical structures. Two main streams of such models are available: models that consider the whole molecular structure to predict a value, namely QSAR (Quantitative Structure Activity Relationships), and models that find relevant substructures to predict a class, namely SAR. The term in silico discovery is applied to chemical design, to computational toxicology, and to drug discovery. We discuss how the experimental practice in biological science is moving more and more toward modeling and simulation. Such virtual experiments confirm hypotheses, provide data for regulation, and help in designing new chemicals. PMID:27311459
Marsden, Kenneth C.; Meyer, Mitchell K.; Grover, Blair K.; Fielding, Randall S.; Wolfensberger, Billy W.
2012-12-18
A casting device includes a covered crucible having a top opening and a bottom orifice, a lid covering the top opening, a stopper rod sealing the bottom orifice, and a reusable mold having at least one chamber, a top end of the chamber being open to and positioned below the bottom orifice and a vacuum tap into the chamber being below the top end of the chamber. A casting method includes charging a crucible with a solid material and covering the crucible, heating the crucible, melting the material, evacuating a chamber of a mold to less than 1 atm absolute through a vacuum tap into the chamber, draining the melted material into the evacuated chamber, solidifying the material in the chamber, and removing the solidified material from the chamber without damaging the chamber.
Cornell, A.A.; Dunbar, J.V.; Ruffner, J.H.
1959-09-29
A semi-automatic method is described for the weld joining of pipes and fittings which utilizes the inert gasshielded consumable electrode electric arc welding technique, comprising laying down the root pass at a first peripheral velocity and thereafter laying down the filler passes over the root pass necessary to complete the weld by revolving the pipes and fittings at a second peripheral velocity different from the first peripheral velocity, maintaining the welding head in a fixed position as to the specific direction of revolution, while the longitudinal axis of the welding head is disposed angularly in the direction of revolution at amounts between twenty minutas and about four degrees from the first position.
Grover, Blair K.; Hubbell, Joel M.; Sisson, James B.; Casper, William L.
2005-12-20
A method for collecting data regarding a matric potential of a media includes providing a tensiometer having a stainless steel tensiometer casing, the stainless steel tensiometer casing comprising a tip portion which includes a wetted porous stainless steel membrane through which a matric potential of a media is sensed; driving the tensiometer into the media using an insertion tube comprising a plurality of probe casing which are selectively coupled to form the insertion tube as the tensiometer is progressively driven deeper into the media, wherein the wetted porous stainless steel membrane is in contact with the media; and sensing the matric potential the media exerts on the wetted porous stainless steel membrane by a pressure sensor in fluid hydraulic connection with the porous stainless steel membrane. A tensiometer includes a stainless steel casing.
NASA Astrophysics Data System (ADS)
Dordain, J. J.
Methods for modeling and characterizing the fuel supply system of liquid propellant rockets subjects to longitudinal vibrations at frequencies between 10 and 100 Hz (the so-called pogo effect) are discussed. The structural, motor and fuel system transfer functions are described. Experimental determination of the transfer matrix of an elementary transfer matrix is outlined. An ultrasonic flowmeter is presented. The methods and the flowmeter were applied to Ariane and Diamant B, eliminating the pogo effect.
Bogoliubov transformations and fermion condensates in lattice field theories
Caracciolo, Sergio Palumbo, Fabrizio Viola, Giovanni
2009-03-15
We apply generalized Bogoliubov transformations to the transfer matrix of relativistic field theories regularized on a lattice. We derive the conditions these transformations must satisfy to factorize the transfer matrix into two terms which propagate fermions and antifermions separately, and we solve the relative equations under some conditions. We relate these equations to the saddle point approximation of a recent bosonization method and to the Foldy-Wouthuysen transformations which separate positive from negative energy states in the Dirac Hamiltonian.
NASA Astrophysics Data System (ADS)
Bowen, Spencer L.; Byars, Larry G.; Michel, Christian J.; Chonde, Daniel B.; Catana, Ciprian
2013-10-01
Kinetic parameters estimated from dynamic 18F-fluorodeoxyglucose (18F-FDG) PET acquisitions have been used frequently to assess brain function in humans. Neglecting partial volume correction (PVC) for a dynamic series has been shown to produce significant bias in model estimates. Accurate PVC requires a space-variant model describing the reconstructed image spatial point spread function (PSF) that accounts for resolution limitations, including non-uniformities across the field of view due to the parallax effect. For ordered subsets expectation maximization (OSEM), image resolution convergence is local and influenced significantly by the number of iterations, the count density, and background-to-target ratio. As both count density and background-to-target values for a brain structure can change during a dynamic scan, the local image resolution may also concurrently vary. When PVC is applied post-reconstruction the kinetic parameter estimates may be biased when neglecting the frame-dependent resolution. We explored the influence of the PVC method and implementation on kinetic parameters estimated by fitting 18F-FDG dynamic data acquired on a dedicated brain PET scanner and reconstructed with and without PSF modelling in the OSEM algorithm. The performance of several PVC algorithms was quantified with a phantom experiment, an anthropomorphic Monte Carlo simulation, and a patient scan. Using the last frame reconstructed image only for regional spread function (RSF) generation, as opposed to computing RSFs for each frame independently, and applying perturbation geometric transfer matrix PVC with PSF based OSEM produced the lowest magnitude bias kinetic parameter estimates in most instances, although at the cost of increased noise compared to the PVC methods utilizing conventional OSEM. Use of the last frame RSFs for PVC with no PSF modelling in the OSEM algorithm produced the lowest bias in cerebral metabolic rate of glucose estimates, although by less than 5% in most
Bowen, Spencer L; Byars, Larry G; Michel, Christian J; Chonde, Daniel B; Catana, Ciprian
2013-10-21
Kinetic parameters estimated from dynamic (18)F-fluorodeoxyglucose ((18)F-FDG) PET acquisitions have been used frequently to assess brain function in humans. Neglecting partial volume correction (PVC) for a dynamic series has been shown to produce significant bias in model estimates. Accurate PVC requires a space-variant model describing the reconstructed image spatial point spread function (PSF) that accounts for resolution limitations, including non-uniformities across the field of view due to the parallax effect. For ordered subsets expectation maximization (OSEM), image resolution convergence is local and influenced significantly by the number of iterations, the count density, and background-to-target ratio. As both count density and background-to-target values for a brain structure can change during a dynamic scan, the local image resolution may also concurrently vary. When PVC is applied post-reconstruction the kinetic parameter estimates may be biased when neglecting the frame-dependent resolution. We explored the influence of the PVC method and implementation on kinetic parameters estimated by fitting (18)F-FDG dynamic data acquired on a dedicated brain PET scanner and reconstructed with and without PSF modelling in the OSEM algorithm. The performance of several PVC algorithms was quantified with a phantom experiment, an anthropomorphic Monte Carlo simulation, and a patient scan. Using the last frame reconstructed image only for regional spread function (RSF) generation, as opposed to computing RSFs for each frame independently, and applying perturbation geometric transfer matrix PVC with PSF based OSEM produced the lowest magnitude bias kinetic parameter estimates in most instances, although at the cost of increased noise compared to the PVC methods utilizing conventional OSEM. Use of the last frame RSFs for PVC with no PSF modelling in the OSEM algorithm produced the lowest bias in cerebral metabolic rate of glucose estimates, although by less than 5% in
From Method to Post Method: A Panacea!
ERIC Educational Resources Information Center
Masouleh, Nima Shakouri
2012-01-01
The foundation of language teaching has undergone many changes. The rise and fall of language teaching methods depends upon a variety of factors extrinsic to a method itself and often reflects the influence of profit-seekers and promoters, as well as the forces of the intellectual marketplace. There was always a source of contention among people…
The Multidimensional WKB Method.
ERIC Educational Resources Information Center
Knudson, Stephen K.; Noid, D. W.
1989-01-01
Discusses a new method for determining the eigenvalues of the Schroedinger equation when the potential energy function does not have a simple form. Describes the mathematical methods and provides an application. Lists limitations to the method. (MVL)
Hybrid functional description of the rhombohedrally distorted B1-structured MnO
NASA Astrophysics Data System (ADS)
Franchini, Cesare; Hirshl, Robin; Bayer, Veronika
2005-03-01
We report a first principle calculation of the ground state properties of MnO within the plane wave based PBE0 hybrid density functional approach developed on the projector augmented wave scheme VASP (Vienna {ab initio} Simulation Package). The insulating, antiferromagnetically ordered and rhombohedrally distorted B1 structure is found to be the most stable phase, consistent with experiment. The gap (4.02 eV), magnetic moment (4.52 m/B), optimum lattice constant (4.40 A), rhombohedral distortion angle (0.88), density of states, and exchange integrals, are all in good agreement with experiment. Our findings confirm the picture which places MnO in the intermediate charge-transfer/Mott-Hubbard regime and suggest that the parameter-free PBE0 hybrid functional method, combining the full nonlocal exact exchange interaction with the PBE exchange-correlation functional well correct the deficiency of conventional DFT, thus providing a accurate description of this correlated material.
NASA Technical Reports Server (NTRS)
Freed, Alan D.
1996-01-01
There are many aspects to consider when designing a Rosenbrock-Wanner-Wolfbrandt (ROW) method for the numerical integration of ordinary differential equations (ODE's) solving initial value problems (IVP's). The process can be simplified by constructing ROW methods around good Runge-Kutta (RK) methods. The formulation of a new, simple, embedded, third-order, ROW method demonstrates this design approach.
Radiochemical method development
Erickson, M.D.; Aldstadt, J.H.; Alvarado, J.S.; Crain, J.S.; Orlandini, K.A.; Smith, L.L.
1994-09-01
The authors have developed methods for chemical characterization of the environment under a multitask project that focuses on improvement of radioanalytical methods with an emphasis on faster and cheaper routine methods. The authors have developed improved methods for separation of environmental levels of technetium-99, radium, and actinides from soil and water; separation of actinides from soil and water matrix interferences; and isolation of strontium. They are also developing methods for simultaneous detection of multiple isotopes (including nonradionuclides) by using a new instrumental technique, inductively coupled plasma-mass spectrometry (ICP-MS). The new ICP-MS methods have greater sensitivity and efficiency and could replace many radiometric techniques. They are using flow injection analysis to integrate and automate the separation methods with the ICP-MS methodology. The final product of all activities will be methods that are available (published in the U.S. Department of Energy`s analytical methods compendium) and acceptable for use in regulatory situations.
[Medical Equipment Maintenance Methods].
Liu, Hongbin
2015-09-01
Due to the high technology and the complexity of medical equipment, as well as to the safety and effectiveness, it determines the high requirements of the medical equipment maintenance work. This paper introduces some basic methods of medical instrument maintenance, including fault tree analysis, node method and exclusive method which are the three important methods in the medical equipment maintenance, through using these three methods for the instruments that have circuit drawings, hardware breakdown maintenance can be done easily. And this paper introduces the processing methods of some special fault conditions, in order to reduce little detours in meeting the same problems. Learning is very important for stuff just engaged in this area.
Selecting Needs Analysis Methods.
ERIC Educational Resources Information Center
Newstrom, John W.; Lilyquist, John M.
1979-01-01
Presents a contingency model for decision making with regard to needs analysis methods. Focus is on 12 methods with brief discussion of their defining characteristics and some operational guidelines for their use. (JOW)
Redefining the "Scientific Method".
ERIC Educational Resources Information Center
Spiece, Kelly R.; Colosi, Joseph
2000-01-01
Surveys 15 introductory biology textbooks for their presentation of the scientific method. Teaching the scientific method involves more than simplified steps and subjectivity--human politics, cultural influences, and chance are all a part of science. Presents an activity for students to experience the scientific method. (Contains 34 references.)…
NASA Technical Reports Server (NTRS)
Bolshakov, A. A.
1985-01-01
The study of Earth from space with specialized satellites, and from manned orbiting stations, has become important in the space programs. The broad complex of methods used for probing Earth from space are different methods of the study of ocean, dynamics. The different methods of ocean observation are described.
1993-12-31
Chapter 4, discusses the various techniques used in the study human cytogenetics. The methods are discussed in historical order, from direct methods to tissue culture techniques, prenatal studies, meiotic studies, sex chromatin techniques, banding techniques, prophase banding and replication studies. Nomenclature of human chromosomes and quantitative methods are also mentioned. 60 refs., 3 figs.
Geobacteraceae strains and methods
Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana
2015-07-07
Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.
Accelerated molecular dynamics methods
Perez, Danny
2011-01-04
The molecular dynamics method, although extremely powerful for materials simulations, is limited to times scales of roughly one microsecond or less. On longer time scales, dynamical evolution typically consists of infrequent events, which are usually activated processes. This course is focused on understanding infrequent-event dynamics, on methods for characterizing infrequent-event mechanisms and rate constants, and on methods for simulating long time scales in infrequent-event systems, emphasizing the recently developed accelerated molecular dynamics methods (hyperdynamics, parallel replica dynamics, and temperature accelerated dynamics). Some familiarity with basic statistical mechanics and molecular dynamics methods will be assumed.
Eigenfields and output beams of an unstable Bessel-Gauss resonator.
Ling, Dongxiong; Li, Chongguang; Li, Junchang
2006-06-10
We evaluate the eigenfields of an unstable Bessel-Gauss resonator (UBGR) by use of the transfer-matrix method in which the transverse profiles and their corresponding losses of the UBGR are considered as the eigenvectors and eigenvalues of a transfer matrix so that the dominant mode fields and their losses of the UBGR can be readily extracted in terms of the matrix eigenvalue algorithm. Moreover, based on the eigenfields across two mirrors that resulted from the transfer-matrix method, we simulate the field distributions in the cavity and the propagation of output beams by means of the angular spectrum method. The computation results show that the UBGR easily produces a fundamental Bessel-Gauss mode of good quality, and the output beams retain the original Bessel-Gauss distribution during propagation. PMID:16761051
[Medical Equipment Maintenance Methods].
Liu, Hongbin
2015-09-01
Due to the high technology and the complexity of medical equipment, as well as to the safety and effectiveness, it determines the high requirements of the medical equipment maintenance work. This paper introduces some basic methods of medical instrument maintenance, including fault tree analysis, node method and exclusive method which are the three important methods in the medical equipment maintenance, through using these three methods for the instruments that have circuit drawings, hardware breakdown maintenance can be done easily. And this paper introduces the processing methods of some special fault conditions, in order to reduce little detours in meeting the same problems. Learning is very important for stuff just engaged in this area. PMID:26904890
NASA Technical Reports Server (NTRS)
McKay, David S.; Cooper, Bonnie L.
2010-01-01
This slide presentation describes new fractionation methods that are used to create dust that is respirable for testing the effects of inhalation of lunar dust in preparation for future manned lunar exploration. Because lunar dust is a very limited commodity, a method that does not result in loss of the material had to be developed. The dust separation system that is described incorporates some traditional methods, while preventing the dust from being contaminated or changed in reactivity properties while also limiting losses.
DIAGNOSTIC METHODS IN AYURVEDA
Thakar, V. J.
1982-01-01
This is an analytical study of the Diagnostic methods Prescribes in Ayurveda. As in the case of disease and treatments the concept of diagnosis also is unique in Ayurveda. It goes to the Nidana of Doshicimbalance by studying the physical, physiological, psychic and behavoural aspects of the patient. The paper gives an insight into the various diagnostic methods enunciated in Sastras which turns out to be a fore-runner of any of modern diagnostic methods. PMID:22556480
The Schwinger Variational Method
NASA Technical Reports Server (NTRS)
Huo, Winifred M.
1995-01-01
Variational methods have proven invaluable in theoretical physics and chemistry, both for bound state problems and for the study of collision phenomena. For collisional problems they can be grouped into two types: those based on the Schroedinger equation and those based on the Lippmann-Schwinger equation. The application of the Schwinger variational (SV) method to e-molecule collisions and photoionization has been reviewed previously. The present chapter discusses the implementation of the SV method as applied to e-molecule collisions.
NASA Technical Reports Server (NTRS)
Zang, Thomas A.; Streett, Craig L.; Hussaini, M. Yousuff
1989-01-01
One of the objectives of these notes is to provide a basic introduction to spectral methods with a particular emphasis on applications to computational fluid dynamics. Another objective is to summarize some of the most important developments in spectral methods in the last two years. The fundamentals of spectral methods for simple problems will be covered in depth, and the essential elements of several fluid dynamical applications will be sketched.
Multigrid contact detection method
NASA Astrophysics Data System (ADS)
He, Kejing; Dong, Shoubin; Zhou, Zhaoyao
2007-03-01
Contact detection is a general problem of many physical simulations. This work presents a O(N) multigrid method for general contact detection problems (MGCD). The multigrid idea is integrated with contact detection problems. Both the time complexity and memory consumption of the MGCD are O(N) . Unlike other methods, whose efficiencies are influenced strongly by the object size distribution, the performance of MGCD is insensitive to the object size distribution. We compare the MGCD with the no binary search (NBS) method and the multilevel boxing method in three dimensions for both time complexity and memory consumption. For objects with similar size, the MGCD is as good as the NBS method, both of which outperform the multilevel boxing method regarding memory consumption. For objects with diverse size, the MGCD outperform both the NBS method and the multilevel boxing method. We use the MGCD to solve the contact detection problem for a granular simulation system based on the discrete element method. From this granular simulation, we get the density property of monosize packing and binary packing with size ratio equal to 10. The packing density for monosize particles is 0.636. For binary packing with size ratio equal to 10, when the number of small particles is 300 times as the number of big particles, the maximal packing density 0.824 is achieved.
NASA Technical Reports Server (NTRS)
Liou, Meng-Sing
1995-01-01
A unique formulation of describing fluid motion is presented. The method, referred to as 'extended Lagrangian method,' is interesting from both theoretical and numerical points of view. The formulation offers accuracy in numerical solution by avoiding numerical diffusion resulting from mixing of fluxes in the Eulerian description. The present method and the Arbitrary Lagrangian-Eulerian (ALE) method have a similarity in spirit-eliminating the cross-streamline numerical diffusion. For this purpose, we suggest a simple grid constraint condition and utilize an accurate discretization procedure. This grid constraint is only applied to the transverse cell face parallel to the local stream velocity, and hence our method for the steady state problems naturally reduces to the streamline-curvature method, without explicitly solving the steady stream-coordinate equations formulated a priori. Unlike the Lagrangian method proposed by Loh and Hui which is valid only for steady supersonic flows, the present method is general and capable of treating subsonic flows and supersonic flows as well as unsteady flows, simply by invoking in the same code an appropriate grid constraint suggested in this paper. The approach is found to be robust and stable. It automatically adapts to flow features without resorting to clustering, thereby maintaining rather uniform grid spacing throughout and large time step. Moreover, the method is shown to resolve multi-dimensional discontinuities with a high level of accuracy, similar to that found in one-dimensional problems.
Microalgal immobilization methods.
Moreno-Garrido, Ignacio
2013-01-01
In this review, methods for the most common microalgal immobilization procedures are gathered and described. Passive (due to natural adherence of cells to surfaces) and active immobilization methods should be distinguished. Among active immobilization methods, calcium alginate entrapment is the most widely used method if living cells are intended to be immobilized, due to the chemical, optical, and mechanical characteristics of this substance. Immobilization in synthetic foams, immobilization in agar and carrageenan as well as immobilization in silica-based matrix or filters are also discussed and described. Finally, some considerations on the use of flocculation for microalgae are mentioned.
Fact Sheet Proven Weight Loss Methods What can weight loss do for you? Losing weight can improve your health in a number of ways. It can lower ... at www.hormone.org/Spanish . Proven Weight Loss Methods Fact Sheet www.hormone.org
NASA Technical Reports Server (NTRS)
Hafez, M.
1989-01-01
Vector potential and related methods, for the simulation of both inviscid and viscous flows over aerodynamic configurations, are briefly reviewed. The advantages and disadvantages of several formulations are discussed and alternate strategies are recommended. Scalar potential, modified potential, alternate formulations of Euler equations, least-squares formulation, variational principles, iterative techniques and related methods, and viscous flow simulation are discussed.
The Comparative Method Revisited.
ERIC Educational Resources Information Center
Sanford, Glenn M.; Lutterschmidt, William I.; Hutchison, Victor H.
2002-01-01
Describes the history of comparative methods and their use in biology as an investigative philosophy. Discusses Bernard's and Krogh's ideas and supports Jorgensen's arguments. Explains conceptual change in the comparative studies which is referred to as "comparative phylogenetic method". (Contains 33 references.) (YDS)
Metalworking method for composites
NASA Technical Reports Server (NTRS)
Divecha, A. P.
1976-01-01
Effective fabrication methods for aluminum/boron and aluminum/graphite composites have been investigated. Drawing and rolling were found to be adaptable to Al/B fabrication. Although graphite composites are not amenable to standard metal processing methods, it may be possible to reduce fabrication costs of Al/C through electron-beam heating.
Chainer, Timothy J.; Dang, Hien P.; Parida, Pritish R.; Schultz, Mark D.; Sharma, Arun
2015-08-11
A method aspect for removing heat from a data center may use liquid coolant cooled without vapor compression refrigeration on a liquid cooled information technology equipment rack. The method may also include regulating liquid coolant flow to the data center through a range of liquid coolant flow values with a controller-apparatus based upon information technology equipment temperature threshold of the data center.
ERIC Educational Resources Information Center
Ember, Lois R.
1977-01-01
The procedures utilized by the Association of Official Analytical Chemists (AOAC) to develop, evaluate, and validate analytical methods for the analysis of chemical pollutants are detailed. Methods validated by AOAC are used by the EPA and FDA in their enforcement programs and are granted preferential treatment by the courts. (BT)
ERIC Educational Resources Information Center
Blystone, Robert V.; Blodgett, Kevin
2006-01-01
The scientific method is the principal methodology by which biological knowledge is gained and disseminated. As fundamental as the scientific method may be, its historical development is poorly understood, its definition is variable, and its deployment is uneven. Scientific progress may occur without the strictures imposed by the formal…
NASA Technical Reports Server (NTRS)
Duval, A
1922-01-01
Different maps and scales are discussed with particular emphasis on their use in aviation. The author makes the observation that current navigation methods are slow and dangerous and should be replaced by scientific methods of navigation based on loxodromy and the use of the compass.
ERIC Educational Resources Information Center
Wankat, Phillip C.
1984-01-01
Discusses a simple method for following the movement of a solute in an adsorption or ion exchange system. This movement is used to study a variety of operational methods, including continuous flow and pulsed flow counter-current operations and simulated counter-current systems. Effect of changing thermodynamic variables is also considered. (JM)
ERIC Educational Resources Information Center
Montgomery, Joel R.
2008-01-01
This working paper explores contemporary research related to methods for teaching reading in Spanish and English in bilingual, foreign language, and English as a second language (ESL) classrooms. Changes stemming from innovations in research and learning are identified and a table is provided to compare methods of teaching reading in Spanish and…
ERIC Educational Resources Information Center
BOUCHER, JOHN G.
THE AUTHOR STATES THAT BEFORE PRESENT FOREIGN LANGUAGE TEACHING METHODS CAN BE DISCUSSED INTELLIGENTLY, THE RESEARCH IN PSYCHOLOGY AND LINGUISTICS WHICH HAS INFLUENCED THE DEVELOPMENT OF THESE METHODS MUST BE CONSIDERED. MANY FOREIGN LANGUAGE TEACHERS WERE BEGINNING TO FEEL COMFORTABLE WITH THE AUDIOLINGUAL APPROACH WHEN NOAM CHOMSKY, IN HIS 1966…
ERIC Educational Resources Information Center
Greenslade, Thomas B., Jr.; Miller, Franklin, Jr.
1981-01-01
Describes method for locating images in simple and complex systems of thin lenses and spherical mirrors. The method helps students to understand differences between real and virtual images. It is helpful in discussing the human eye and the correction of imperfect vision by the use of glasses. (Author/SK)
ERIC Educational Resources Information Center
Del Grande, John
1993-01-01
Describes the method that Archimedes utilized to calculate the volumes of spheres and other solids. The method found the volume of a sphere by comparing the mass of parallel slices of a sphere and a cone with that of a cylinder of known mass. (MDH)
NASA Technical Reports Server (NTRS)
Hussaini, M. Y.; Kopriva, D. A.; Patera, A. T.
1987-01-01
This review covers the theory and application of spectral collocation methods. Section 1 describes the fundamentals, and summarizes results pertaining to spectral approximations of functions. Some stability and convergence results are presented for simple elliptic, parabolic, and hyperbolic equations. Applications of these methods to fluid dynamics problems are discussed in Section 2.
ERIC Educational Resources Information Center
Boulton, L. H.
1973-01-01
Discusses application of Schoniger's method of quantitative organic elemental analysis in teaching of qualitative analysis of the halogens, nitrogen, sulphur, and phosphorus. Indicates that the oxygen flask method is safe and suitable for both high school and college courses because of simple apparatus requirements. (CC)
Improved nonlinear prediction method
NASA Astrophysics Data System (ADS)
Adenan, Nur Hamiza; Md Noorani, Mohd Salmi
2014-06-01
The analysis and prediction of time series data have been addressed by researchers. Many techniques have been developed to be applied in various areas, such as weather forecasting, financial markets and hydrological phenomena involving data that are contaminated by noise. Therefore, various techniques to improve the method have been introduced to analyze and predict time series data. In respect of the importance of analysis and the accuracy of the prediction result, a study was undertaken to test the effectiveness of the improved nonlinear prediction method for data that contain noise. The improved nonlinear prediction method involves the formation of composite serial data based on the successive differences of the time series. Then, the phase space reconstruction was performed on the composite data (one-dimensional) to reconstruct a number of space dimensions. Finally the local linear approximation method was employed to make a prediction based on the phase space. This improved method was tested with data series Logistics that contain 0%, 5%, 10%, 20% and 30% of noise. The results show that by using the improved method, the predictions were found to be in close agreement with the observed ones. The correlation coefficient was close to one when the improved method was applied on data with up to 10% noise. Thus, an improvement to analyze data with noise without involving any noise reduction method was introduced to predict the time series data.
Geopositional Statistical Methods
NASA Technical Reports Server (NTRS)
Ross, Kenton
2006-01-01
RMSE based methods distort circular error estimates (up to 50% overestimation). The empirical approach is the only statistically unbiased estimator offered. Ager modification to Shultz approach is nearly unbiased, but cumbersome. All methods hover around 20% uncertainty (@ 95% confidence) for low geopositional bias error estimates. This requires careful consideration in assessment of higher accuracy products.
ERIC Educational Resources Information Center
OKADA, TETSUO
THIS NOTE DESCRIBES AND CRITICIZES THE VARIOUS METHODS CURRENTLY IN USE FOR PROJECTING BIRTHS--(1) COHORT-FERTILITY, (2) AGE-SPECIFIC, (3) COHORT-FERTILITY (SCRIPPS), AND (4) MARRIAGE-PARITY-PROGRESSION. VARIABLES USED IN THE VARIOUS METHODS ARE AGE OF MOTHER, COMPLETED FERTILITY, MARRIAGE STATUS, TIME SINCE MARRIAGE, PARITY, AND BIRTH INTERVAL.…
Methods for data classification
Garrity, George; Lilburn, Timothy G.
2011-10-11
The present invention provides methods for classifying data and uncovering and correcting annotation errors. In particular, the present invention provides a self-organizing, self-correcting algorithm for use in classifying data. Additionally, the present invention provides a method for classifying biological taxa.
ERIC Educational Resources Information Center
Check, Joseph; Schutt, Russell K.
2011-01-01
"Research Methods in Education" introduces research methods as an integrated set of techniques for investigating questions about the educational world. This lively, innovative text helps students connect technique and substance, appreciate the value of both qualitative and quantitative methodologies, and make ethical research decisions.…
Method of forming nanodielectrics
Tuncer, Enis [Knoxville, TN; Polyzos, Georgios [Oak Ridge, TN
2014-01-07
A method of making a nanoparticle filled dielectric material. The method includes mixing nanoparticle precursors with a polymer material and reacting the nanoparticle mixed with the polymer material to form nanoparticles dispersed within the polymer material to form a dielectric composite.
Martin, Frank S.; Silver, Gary L.
1991-04-30
A method for reducing the concentration of any undesirable metals dissolved in contaminated water, such as waste water. The method involves uniformly reacting the contaminated water with an excess amount of solid particulate calcium sulfite to insolubilize the undesirable metal ions, followed by removal thereof and of the unreacted calcium sulfite.
Martin, F.S.; Silver, G.L.
1990-02-02
A method for reducing the concentration of many undesirable metals dissolved in contaminated water, such as waste water. The method involves uniformly reacting the contaminated water with an excess amount of solid particulate calcium sulfite to insolubilize the undesirable metal ions, followed by removal thereof and of the unreacted calcium sulfite. 1 tab.
Decker, David L; Lyles, Brad F; Purcell, Richard G; Hershey, Ronald Lee
2014-05-20
An apparatus and method for supporting a tubing bundle during installation or removal. The apparatus includes a clamp for securing the tubing bundle to an external wireline. The method includes deploying the tubing bundle and wireline together, The tubing bundle is periodically secured to the wireline using a clamp.
Martin, F.S.; Silver, G.L.
1991-04-30
A method is described for reducing the concentration of any undesirable metals dissolved in contaminated water, such as waste water. The method involves uniformly reacting the contaminated water with an excess amount of solid particulate calcium sulfite to insolubilize the undesirable metal ions, followed by removal thereof and of the unreacted calcium sulfite.
The Schwinger Variational Method
NASA Technical Reports Server (NTRS)
Huo, Winifred M.
1995-01-01
Variational methods have proven invaluable in theoretical physics and chemistry, both for bound state problems and for the study of collision phenomena. The application of the Schwinger variational (SV) method to e-molecule collisions and molecular photoionization has been reviewed previously. The present chapter discusses the implementation of the SV method as applied to e-molecule collisions. Since this is not a review of cross section data, cross sections are presented only to server as illustrative examples. In the SV method, the correct boundary condition is automatically incorporated through the use of Green's function. Thus SV calculations can employ basis functions with arbitrary boundary conditions. The iterative Schwinger method has been used extensively to study molecular photoionization. For e-molecule collisions, it is used at the static exchange level to study elastic scattering and coupled with the distorted wave approximation to study electronically inelastic scattering.
Introduction to multigrid methods
NASA Technical Reports Server (NTRS)
Wesseling, P.
1995-01-01
These notes were written for an introductory course on the application of multigrid methods to elliptic and hyperbolic partial differential equations for engineers, physicists and applied mathematicians. The use of more advanced mathematical tools, such as functional analysis, is avoided. The course is intended to be accessible to a wide audience of users of computational methods. We restrict ourselves to finite volume and finite difference discretization. The basic principles are given. Smoothing methods and Fourier smoothing analysis are reviewed. The fundamental multigrid algorithm is studied. The smoothing and coarse grid approximation properties are discussed. Multigrid schedules and structured programming of multigrid algorithms are treated. Robustness and efficiency are considered.
Raj, Rishi; Cologna, Marco; Francis, John S.
2016-05-10
This disclosure provides methods of flash sintering and compositions created by these methods. Methods for sintering multilayered bodies are provided in which a sintered body is produced in less than one minute. In one aspect, each layer is of a different composition, and may be constituted wholly from a ceramic or from a combination of ceramic and metallic particles. When the body includes a layer of an anode composition, a layer of an electrolyte composition and a layer of a cathode composition, the sintered body can be used to produce a solid oxide fuel cell.
Generalized subspace correction methods
Kolm, P.; Arbenz, P.; Gander, W.
1996-12-31
A fundamental problem in scientific computing is the solution of large sparse systems of linear equations. Often these systems arise from the discretization of differential equations by finite difference, finite volume or finite element methods. Iterative methods exploiting these sparse structures have proven to be very effective on conventional computers for a wide area of applications. Due to the rapid development and increasing demand for the large computing powers of parallel computers, it has become important to design iterative methods specialized for these new architectures.
Jackson, D.D.; Hollen, R.M.
1981-02-27
A method of very thoroughly and quikcly cleaning a guaze electrode used in chemical analyses is given, as well as an automobile cleaning apparatus which makes use of the method. The method generates very little waste solution, and this is very important in analyzing radioactive materials, especially in aqueous solutions. The cleaning apparatus can be used in a larger, fully automated controlled potential coulometric apparatus. About 99.98% of a 5 mg plutonium sample was removed in less than 3 minutes, using only about 60 ml of rinse solution and two main rinse steps.
NASA Technical Reports Server (NTRS)
Seeber, F
1939-01-01
After a brief survey of the commonly used single-value test methods, the importance of the determination of the incipient knock for the octane number is discussed and improvements suggested for the knock testing in the CFR engine. The DVL supercharge test method with its superiority of direct determination of fuel knock in each single cylinder of an airplane engine without involving structural changes, is described and the advantages of a multiple-value method enumerated. A diagrammatic presentation of the knock characteristics is presented.
Method for inducing hypothermia
Becker, Lance B.; Hoek, Terry Vanden; Kasza, Kenneth E.
2003-04-15
Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.
Method for inducing hypothermia
Becker, Lance B.; Hoek, Terry Vanden; Kasza, Kenneth E.
2005-11-08
Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.
Method for inducing hypothermia
Becker, Lance B.; Hoek, Terry Vanden; Kasza, Kenneth E.
2008-09-09
Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.
Mourant, Judith R.; Anderson, Gerhard D.; Bigio, Irving J.; Johnson, Tamara M.
1996-01-01
Method for fusing bone. The present invention is a method for joining hard tissue which includes chemically removing the mineral matrix from a thin layer of the surfaces to be joined, placing the two bones together, and heating the joint using electromagnetic radiation. The goal of the method is not to produce a full-strength weld of, for example, a cortical bone of the tibia, but rather to produce a weld of sufficient strength to hold the bone halves in registration while either external fixative devices are applied to stabilize the bone segments, or normal healing processes restore full strength to the tibia.
Miner, Nadine E.; Caudell, Thomas P.
2004-06-08
A sound synthesis method for modeling and synthesizing dynamic, parameterized sounds. The sound synthesis method yields perceptually convincing sounds and provides flexibility through model parameterization. By manipulating model parameters, a variety of related, but perceptually different sounds can be generated. The result is subtle changes in sounds, in addition to synthesis of a variety of sounds, all from a small set of models. The sound models can change dynamically according to changes in the simulation environment. The method is applicable to both stochastic (impulse-based) and non-stochastic (pitched) sounds.
Tadd, Andrew R; Schwank, Johannes
2013-05-14
A catalytic reforming method is disclosed herein. The method includes sequentially supplying a plurality of feedstocks of variable compositions to a reformer. The method further includes adding a respective predetermined co-reactant to each of the plurality of feedstocks to obtain a substantially constant output from the reformer for the plurality of feedstocks. The respective predetermined co-reactant is based on a C/H/O atomic composition for a respective one of the plurality of feedstocks and a predetermined C/H/O atomic composition for the substantially constant output.
Method for synthesizing boracities
Wolf, Gary A [Kennewick, WA
1982-01-01
A method for producing boracites is disclosed in which a solution of divalent metal acetate, boric acid, and halogen acid is evaporated to dryness and the resulting solid is heated in an inert atmosphere under pressure.
ERIC Educational Resources Information Center
Zahorik, John A.
1973-01-01
The purpose of this paper is to examine a problem that exists in relation to teaching methods and which has quite possibly served to limit the value of many promising methodologies that have been developed. (Author)
Plasma isotope separation methods
Grossman, M.W. ); Shepp, T.A. )
1991-12-01
Isotope separation has many important industrial, medical, and research applications. Large-scale processes have typically utilized complex cascade systems; for example, the gas centrifuge. Alternatively, high single-stage enrichment processes (as in the case of the calutron) are very energy intensive. Plasma-based methods being developed for the past 15 to 20 years have attempted to overcome these two drawbacks. In this review, six major types of isotope separation methods which involve plasma phenomena are discussed. These methods are: plasma centrifuge, AVLIS (atomic vapor laser isotope separation), ion wave, ICR (ion-cyclotron resonance), calutron, and gas discharge. The emphasis of this paper is to describe the plasma phenomena in these major categories. An attempt was made to include enough references so that more detailed study or evaluation of a particular method could readily be pursued. A brief discussion of isotope separation using mass balance concepts is also carried out.
Adaptive Algebraic Multigrid Methods
Brezina, M; Falgout, R; MacLachlan, S; Manteuffel, T; McCormick, S; Ruge, J
2004-04-09
Our ability to simulate physical processes numerically is constrained by our ability to solve the resulting linear systems, prompting substantial research into the development of multiscale iterative methods capable of solving these linear systems with an optimal amount of effort. Overcoming the limitations of geometric multigrid methods to simple geometries and differential equations, algebraic multigrid methods construct the multigrid hierarchy based only on the given matrix. While this allows for efficient black-box solution of the linear systems associated with discretizations of many elliptic differential equations, it also results in a lack of robustness due to assumptions made on the near-null spaces of these matrices. This paper introduces an extension to algebraic multigrid methods that removes the need to make such assumptions by utilizing an adaptive process. The principles which guide the adaptivity are highlighted, as well as their application to algebraic multigrid solution of certain symmetric positive-definite linear systems.
Mathematics Case Methods Project.
ERIC Educational Resources Information Center
Barnett, Carne S.
1998-01-01
Presents an overview and analysis of the Mathematics Case Methods Project, which uses cases in order to examine and reflect upon teaching. Focuses on a special kind of teacher knowledge, coined pedagogical-content knowledge. (ASK)
Patriarca, P.; Slaughter, G.M.
1962-11-27
A method of joining metal surfaces is given. Surfaces having nickel or iron as the base metal are joined together with a brazing composition consisting of 80% nickel, 10% phosphorus, and 10% chromium. (AEC)
Kaneko, K.
1987-02-01
A relationship between the number projection and the shell model methods is investigated in the case of a single-j shell. We can find a one-to-one correspondence between the number projected and the shell model states.
Comparative Card Production Methods
ERIC Educational Resources Information Center
Turner, Ann Craig
1972-01-01
Seven methods of card production tried by the University of British Columbia library are described and compared in terms of total cost per set of cards and their applicability to libraries of various sizes. (5 references) (Author)
Method for making organyltriorganooxysilanes
Schattenmann, Florian Johannes
2002-01-01
A method for the preparation of organyltriorganooxysilanes containing at least one silicon-carbon bond is provided comprising reacting at least one tetraorganooxysilane with an activated carbon and at least one base.
Concrete compositions and methods
Chen, Irvin; Lee, Patricia Tung; Patterson, Joshua
2015-06-23
Provided herein are compositions, methods, and systems for cementitious compositions containing calcium carbonate compositions and aggregate. The compositions find use in a variety of applications, including use in a variety of building materials and building applications.
ERIC Educational Resources Information Center
Dolan, Thomas G.
2003-01-01
Describes project delivery methods that are replacing the traditional Design/Bid/Build linear approach to the management, design, and construction of new facilities. These variations can enhance construction management and teamwork. (SLD)
Anderson, N.G.
1963-01-29
An improved method of sedimentation is described. A series of spaced surfaces of powdered material positioned normal to the centrifugal field concentrates the larger, slower moving molecules of a liquid and hastens sedimentation. (AEC)
Method for making organooxysilanes
Schattenmann, Florian Johannes
2003-12-23
A method for the preparation of organooxysilanes containing at least one silicon-carbon bond is provided which comprises reacting at least one tetraorganooxysilane with at least one transition metal organo compound.
NASA Technical Reports Server (NTRS)
Bement, Laurence J.; Schimmel, Morry L.
1989-01-01
To overcome serious weaknesses in determining the performance of initiating devices, a novel 'ignitability test method', representing actual design interfaces and ignition materials, has been developed. Ignition device output consists of heat, light, gas an burning particles. Past research methods have evaluated these parameters individually. This paper describes the development and demonstration of an ignitability test method combining all these parameters, and the quantitative assessment of the ignition performance of two widely used percussion primers, the M42C1-PA101 and the M42C2-793. The ignition materials used for this evaluation were several powder, granule and pellet sizes of black powder and boron-potassium nitrate. This test method should be useful for performance evaluation of all initiator types, quality assurance, evaluation of ignition interfaces, and service life studies of initiators and ignition materials.
NASA Technical Reports Server (NTRS)
Oza, Nikunj C.
2004-01-01
Ensemble Data Mining Methods, also known as Committee Methods or Model Combiners, are machine learning methods that leverage the power of multiple models to achieve better prediction accuracy than any of the individual models could on their own. The basic goal when designing an ensemble is the same as when establishing a committee of people: each member of the committee should be as competent as possible, but the members should be complementary to one another. If the members are not complementary, Le., if they always agree, then the committee is unnecessary---any one member is sufficient. If the members are complementary, then when one or a few members make an error, the probability is high that the remaining members can correct this error. Research in ensemble methods has largely revolved around designing ensembles consisting of competent yet complementary models.
NASA Technical Reports Server (NTRS)
Berkowitz, J. B.; Emerson, N. H.
1972-01-01
Results are presented of a comprehensive search of the literature available, much of which has been generated by the research centers of NASA and its contractors, on plating and coating methods and techniques. Methods covered included: (1) electroplating from aqueous solutions; (2) electroplating from nonaqueous solutions; (3) electroplating from fused-salt baths; (4) electroforming; (5) electroless plating, immersion plating, and mirroring; (6) electroplating from gaseous plasmas; and (7) anodized films and conversion coatings.
Takemoto, Kyoto; Scuzzo, Giuseppe; Lombardo, L U C A; Takemoto, Y U I
2009-12-01
The mushroom arch-wire is mainly used in lingual orthodontic treatment but the complicated wire bending it requires affects both the treatment results and the time spent at the chair. The author proposes a new lingual straight wire method (LSW) in order to facilitate arch coordination and simplify the mechanics. The attention paid to the set-up model and bracket positioning and bonding plus the use of the new LSW method will also improve patient comfort.
Henn, Fritz
2013-04-09
Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.
Henn, Fritz
2012-01-24
Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.
Method of saccharifying cellulose
Johnson, Eric A.; Demain, Arnold L.; Madia, Ashwin
1985-09-10
A method of saccharifying cellulose by incubation with the cellulase of Clostridium thermocellum in a broth containing an efficacious amount of a reducing agent. Other incubation parameters which may be advantageously controlled to stimulate saccharification include the concentration of alkaline earth salts, pH, temperature, and duration. By the method of the invention, even native crystalline cellulose such as that found in cotton may be completely saccharified.
Method of saccharifying cellulose
Johnson, E.A.; Demain, A.L.; Madia, A.
1983-05-13
A method is disclosed of saccharifying cellulose by incubation with the cellulase of Clostridium thermocellum in a broth containing an efficacious amount of thiol reducing agent. Other incubation parameters which may be advantageously controlled to stimulate saccharification include the concentration of alkaline earth salts, pH, temperature, and duration. By the method of the invention, even native crystalline cellulose such as that found in cotton may be completely saccharified.
NASA Technical Reports Server (NTRS)
Bement, Laurence J.; Schimmel, Morry L.
1990-01-01
To determine functional performance of initiating devices, the NASA's Langley Research Center's novel ignitability research on percussion primers has been expanded in 1989 to include measurements of function time, the evaluation of six primer lots (five types), and the determination of the effects of the military cold-temperature requirement of -65 F and primer output closure disks. This test method, a major improvement over the prior primer output test methods, fully met all objectives, while showing a significant amount of ignition variability.
McAdams, Wm.A.; Foss, M.H.
1958-08-12
A method of testing containers for leaks is described, particularly the testing of containers or cans in which the uranium slugs for nuelear reactors are jacketed. This method involves the immersion of the can in water under l50 pounds of pressure, then removing, drying, and coating the can with anhydrous copper sulfate. Amy water absorbed by the can under pressure will exude and discolor the copper sulfate in the area about the leak.
Improved radioanalytical methods
Erickson, M.D.; Aldstadt, J.H.; Alvarado, J.S.; Crain, J.S.; Orlandini, K.A.; Smith, L.L.
1995-12-31
Methods for the chemical characterization of the environment are being developed under a multitask project for the Analytical Services Division (EM-263) within the US Department of Energy (DOE) Office of Environmental Management. This project focuses on improvement of radioanalytical methods with an emphasis on faster and cheaper routine methods. We have developed improved methods, for separation of environmental levels of technetium-99 and strontium-89/90, radium, and actinides from soil and water; and for separation of actinides from soil and water matrix interferences. Among the novel separation techniques being used are element- and class-specific resins and membranes. (The 3M Corporation is commercializing Empore {trademark} membranes under a cooperative research and development agreement [CRADA] initiated under this project). We have also developed methods for simultaneous detection of multiple isotopes using inductively coupled plasma-mass spectrometry (ICP-MS). The ICP-MS method requires less rigorous chemical separations than traditional radiochemical analyses because of its mass-selective mode of detection. Actinides and their progeny have been isolated and concentrated from a variety of natural water matrices by using automated batch separation incorporating selective resins prior to ICP-MS analyses. In addition, improvements in detection limits, sample volume, and time of analysis were obtained by using other sample introduction techniques, such as ultrasonic nebulization and electrothermal vaporization. Integration and automation of the separation methods with the ICP-MS methodology by using flow injection analysis is underway, with an objective of automating methods to achieve more reproducible results, reduce labor costs, cut analysis time, and minimize secondary waste generation through miniaturization of the process.
Methods in Molecular Biophysics
NASA Astrophysics Data System (ADS)
Serdyuk, Igor N.; Zaccai, Nathan R.; Zaccai, Joseph
2001-12-01
Our knowledge of biological macromolecules and their interactions is based on the application of physical methods, ranging from classical thermodynamics to recently developed techniques for the detection and manipulation of single molecules. These methods, which include mass spectrometry, hydrodynamics, microscopy, diffraction and crystallography, electron microscopy, molecular dynamics simulations, and nuclear magnetic resonance, are complementary; each has its specific advantages and limitations. Organised by method, this textbook provides descriptions and examples of applications for the key physical methods in modern biology. It is an invaluable resource for undergraduate and graduate students of molecular biophysics in science and medical schools, as well as research scientists looking for an introduction to techniques beyond their specialty. As appropriate for this interdisciplinary field, the book includes short asides to explain physics aspects to biologists and biology aspects to physicists. Comprehensive coverage and up-to-date treatment of the latest physical methods in modern biology Each method includes a brief historical introduction, theoretical principles, applications, advantages and limitations, and concludes with a checklist of key ideas Interdisciplinary and accessible to biologists, physicists, and those with medical backgrounds
Rosenblatt, J E; Stewart, P R
1975-06-01
In a new method of anaerobic culture, a transparent, gas-impermeable bag is used and the anaerobic environment is established with copper sulfate-saturated steel wool. An Alka-Seltzer tablet generates carbon dioxide. The agar plate surface can be inspected through the bag at any time without interrupting the anaerobic atmosphere or disturbing other specimens. Methylene blue indicator strips are completely reduced by 4 h after the bag is set up and have remained reduced for as long as 3 weeks. Growth of 16 different stock culture anaerobes was generally equivalent by the bag and GasPak jar methods. Yield and growth of anaerobic isolates also were equivalent with 7 of 10 clinical specimens; from the other 3 specimens, 13 isolates were recovered, 5 by both the bag and jar methods and the rest by one method or the other. No consistent differences were found between the anaerobic bag and GasPak jar methods in the yield of anaerobes from clinical specimens. Early growth (24 h of incubation) of anaerobes from one specimen was detected with the bag method. PMID:1100671
Rosenblatt, J E; Stewart, P R
1975-01-01
In a new method of anaerobic culture, a transparent, gas-impermeable bag is used and the anaerobic environment is established with copper sulfate-saturated steel wool. An Alka-Seltzer tablet generates carbon dioxide. The agar plate surface can be inspected through the bag at any time without interrupting the anaerobic atmosphere or disturbing other specimens. Methylene blue indicator strips are completely reduced by 4 h after the bag is set up and have remained reduced for as long as 3 weeks. Growth of 16 different stock culture anaerobes was generally equivalent by the bag and GasPak jar methods. Yield and growth of anaerobic isolates also were equivalent with 7 of 10 clinical specimens; from the other 3 specimens, 13 isolates were recovered, 5 by both the bag and jar methods and the rest by one method or the other. No consistent differences were found between the anaerobic bag and GasPak jar methods in the yield of anaerobes from clinical specimens. Early growth (24 h of incubation) of anaerobes from one specimen was detected with the bag method. Images PMID:1100671
Rodgers, Joel; Foushee, Russell; Terndrup, Thomas E; Gaddis, Gary M
2006-11-01
Incidents of significant consequence that create surge may require special research methods to provide reliable, generalizable results. This report was constructed through a process of literature review, expert panel discussion at the journal's consensus conference, and iterative development. Traditional clinical research methods that are well accepted in medicine are exceptionally difficult to use for surge incidents because the incidents are very difficult to reliably predict, the consequences vary widely, human behaviors are heterogeneous in response to incidents, and temporal conditions prioritize limited resources to response, rather than data collection. Current literature on surge research methods has found some degree of reliability and generalizability in case-control, postincident survey methods, and ethnographical designs. Novel methods that show promise for studying surge include carefully validated simulation experiments and survey methods that produce validated results from representative populations. Methodologists and research scientists should consider quasi-experimental designs and case-control studies in areas with recurrent high-consequence incidents (e.g., earthquakes and hurricanes). Specialists that need to be well represented in areas of research include emergency physicians and critical care physicians, simulation engineers, cost economists, sociobehavioral methodologists, and others.
[Barrier methods of contraception].
Goldsmith, A; Edelman, D A
1982-01-01
Vaginal methods of contraception were the earliest types used and some references to them date back to antiquity. Most of the vaginal contraceptive agents identified by the ancient Greeks, Indians, Japanese, and Chinese have been found in modern laboratory tests to have spermicidal properties, but it is doubtful that the methods were fully reliable or were used by many people. During the 19th century the condom, vaginal spermicides, and diaphragm became available. The development of nonoxynol-9 and other nonirritating but effective spermicidal agents improved vaginal contraceptives greatly by the 1950s, but starting in the 1960s newer methods began to replace the vaginal methods. Interest in barrier methods has been reawakened somewhat by concern about the health effects of hormonal methods. At present all barrier methods leave something to be desired. Failure rates of 3-30% for barrier methods in general have been estimated, but the higher rates are believed due to incorrect or inconsistent use. Theoretical failure rates of condoms and diaphragms have been estimated at 3/100 women-years, but in actual use failure rates may reach 15 for condoms and 13 for diaphragms used with spermicides. Use-effectiveness rates are greatly influenced by motivation. For a variety of reasons, the acceptability of barrier methods is low, especially in developing countries. New developments in spermicidal agents include sperm inhibitors, which impede the fertilizing capacity of sperm rather than attempting a spermicidal effect; a number of such agents have been studied and have proven more effective in animal tests than conventional spermicides. Neosampoon, a new spermicidal foam, has attracted an increasing number of users, especially in developing countries. A new condom, made of thin polymers and containing a standard dose of nonoxynol-9, has been designed to dissolve in the vaginal fluid. Further studies are needed of its acceptability, efficacy, and side effects before it becomes
NASA Technical Reports Server (NTRS)
Henke, Luke
2010-01-01
The ICARE method is a flexible, widely applicable method for systems engineers to solve problems and resolve issues in a complete and comprehensive manner. The method can be tailored by diverse users for direct application to their function (e.g. system integrators, design engineers, technical discipline leads, analysts, etc.). The clever acronym, ICARE, instills the attitude of accountability, safety, technical rigor and engagement in the problem resolution: Identify, Communicate, Assess, Report, Execute (ICARE). This method was developed through observation of Space Shuttle Propulsion Systems Engineering and Integration (PSE&I) office personnel approach in an attempt to succinctly describe the actions of an effective systems engineer. Additionally it evolved from an effort to make a broadly-defined checklist for a PSE&I worker to perform their responsibilities in an iterative and recursive manner. The National Aeronautics and Space Administration (NASA) Systems Engineering Handbook states, engineering of NASA systems requires a systematic and disciplined set of processes that are applied recursively and iteratively for the design, development, operation, maintenance, and closeout of systems throughout the life cycle of the programs and projects. ICARE is a method that can be applied within the boundaries and requirements of NASA s systems engineering set of processes to provide an elevated sense of duty and responsibility to crew and vehicle safety. The importance of a disciplined set of processes and a safety-conscious mindset increases with the complexity of the system. Moreover, the larger the system and the larger the workforce, the more important it is to encourage the usage of the ICARE method as widely as possible. According to the NASA Systems Engineering Handbook, elements of a system can include people, hardware, software, facilities, policies and documents; all things required to produce system-level results, qualities, properties, characteristics
NASA Technical Reports Server (NTRS)
Bond, Thomas H. (Technical Monitor); Anderson, David N.
2004-01-01
This manual reviews the derivation of the similitude relationships believed to be important to ice accretion and examines ice-accretion data to evaluate their importance. Both size scaling and test-condition scaling methods employing the resulting similarity parameters are described, and experimental icing tests performed to evaluate scaling methods are reviewed with results. The material included applies primarily to unprotected, unswept geometries, but some discussion of how to approach other situations is included as well. The studies given here and scaling methods considered are applicable only to Appendix-C icing conditions. Nearly all of the experimental results presented have been obtained in sea-level tunnels. Recommendations are given regarding which scaling methods to use for both size scaling and test-condition scaling, and icing test results are described to support those recommendations. Facility limitations and size-scaling restrictions are discussed. Finally, appendices summarize the air, water and ice properties used in NASA scaling studies, give expressions for each of the similarity parameters used and provide sample calculations for the size-scaling and test-condition scaling methods advocated.
Panel methods: An introduction
NASA Technical Reports Server (NTRS)
Erickson, Larry L.
1990-01-01
Panel methods are numerical schemes for solving (the Prandtl-Glauert equation) for linear, inviscid, irrotational flow about aircraft flying at subsonic or supersonic speeds. The tools at the panel-method user's disposal are (1) surface panels of source-doublet-vorticity distributions that can represent nearly arbitrary geometry, and (2) extremely versatile boundary condition capabilities that can frequently be used for creative modeling. Panel-method capabilities and limitations, basic concepts common to all panel-method codes, different choices that were made in the implementation of these concepts into working computer programs, and various modeling techniques involving boundary conditions, jump properties, and trailing wakes are discussed. An approach for extending the method to nonlinear transonic flow is also presented. Three appendices supplement the main test. In appendix 1, additional detail is provided on how the basic concepts are implemented into a specific computer program (PANAIR). In appendix 2, it is shown how to evaluate analytically the fundamental surface integral that arises in the expressions for influence-coefficients, and evaluate its jump property. In appendix 3, a simple example is used to illustrate the so-called finite part of the improper integrals.
Methods of Melanoma Detection.
Leachman, Sancy A; Cassidy, Pamela B; Chen, Suephy C; Curiel, Clara; Geller, Alan; Gareau, Daniel; Pellacani, Giovanni; Grichnik, James M; Malvehy, Josep; North, Jeffrey; Jacques, Steven L; Petrie, Tracy; Puig, Susana; Swetter, Susan M; Tofte, Susan; Weinstock, Martin A
2016-01-01
Detection and removal of melanoma, before it has metastasized, dramatically improves prognosis and survival. The purpose of this chapter is to (1) summarize current methods of melanoma detection and (2) review state-of-the-art detection methods and technologies that have the potential to reduce melanoma mortality. Current strategies for the detection of melanoma range from population-based educational campaigns and screening to the use of algorithm-driven imaging technologies and performance of assays that identify markers of transformation. This chapter will begin by describing state-of-the-art methods for educating and increasing awareness of at-risk individuals and for performing comprehensive screening examinations. Standard and advanced photographic methods designed to improve reliability and reproducibility of the clinical examination will also be reviewed. Devices that magnify and/or enhance malignant features of individual melanocytic lesions (and algorithms that are available to interpret the results obtained from these devices) will be compared and contrasted. In vivo confocal microscopy and other cellular-level in vivo technologies will be compared to traditional tissue biopsy, and the role of a noninvasive "optical biopsy" in the clinical setting will be discussed. Finally, cellular and molecular methods that have been applied to the diagnosis of melanoma, such as comparative genomic hybridization (CGH), fluorescent in situ hybridization (FISH), and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), will be discussed. PMID:26601859
Methods for Neutron Spectrometry
DOE R&D Accomplishments Database
Brockhouse, Bertram N.
1961-01-09
The appropriate theories and the general philosophy of methods of measurement and treatment of data neutron spectrometry are discussed. Methods of analysis of results for liquids using the Van Hove formulation, and for crystals using the Born-von Karman theory, are reviewed. The most useful of the available methods of measurement are considered to be the crystal spectrometer methods and the pulsed monoenergetic beam/time-of-flight method. Pulsed-beam spectrometers have the advantage of higher counting rates than crystal spectrometers, especially in view of the fact that simultaneous measurements in several counters at different angles of scattering are possible in pulsed-beam spectrometers. The crystal spectrometer permits several valuable new types of specialized experiments to be performed, especially energy distribution measurements at constant momentum transfer. The Chalk River triple-axis crystal-spectrometer is discussed, with reference to its use in making the specialized experiments. The Chalk River rotating crystal (pulsed-beam) spectrometer is described, and a comparison of this type instrument with other pulsed-beam spectrometers is made. A partial outline of the theory of operation of rotating-crystal spectrometers is presented. The use of quartz-crystal filters for fast neutron elimination and for order elimination is discussed. (auth)
Peterman, Dean R [Idaho Falls, ID; Klaehn, John R [Idaho Falls, ID; Harrup, Mason K [Idaho Falls, ID; Tillotson, Richard D [Moore, ID; Law, Jack D [Pocatello, ID
2010-09-21
Methods of separating actinides from lanthanides are disclosed. A regio-specific/stereo-specific dithiophosphinic acid having organic moieties is provided in an organic solvent that is then contacted with an acidic medium containing an actinide and a lanthanide. The method can extend to separating actinides from one another. Actinides are extracted as a complex with the dithiophosphinic acid. Separation compositions include an aqueous phase, an organic phase, dithiophosphinic acid, and at least one actinide. The compositions may include additional actinides and/or lanthanides. A method of producing a dithiophosphinic acid comprising at least two organic moieties selected from aromatics and alkyls, each moiety having at least one functional group is also disclosed. A source of sulfur is reacted with a halophosphine. An ammonium salt of the dithiophosphinic acid product is precipitated out of the reaction mixture. The precipitated salt is dissolved in ether. The ether is removed to yield the dithiophosphinic acid.
Saadd, Y.
1994-12-31
In spite of the tremendous progress achieved in recent years in the general area of iterative solution techniques, there are still a few obstacles to the acceptance of iterative methods in a number of applications. These applications give rise to very indefinite or highly ill-conditioned non Hermitian matrices. Trying to solve these systems with the simple-minded standard preconditioned Krylov subspace methods can be a frustrating experience. With the mathematical and physical models becoming more sophisticated, the typical linear systems which we encounter today are far more difficult to solve than those of just a few years ago. This trend is likely to accentuate. This workshop will discuss (1) these applications and the types of problems that they give rise to; and (2) recent progress in solving these problems with iterative methods. The workshop will end with a hopefully stimulating panel discussion with the speakers.
Bayesian methods in reliability
NASA Astrophysics Data System (ADS)
Sander, P.; Badoux, R.
1991-11-01
The present proceedings from a course on Bayesian methods in reliability encompasses Bayesian statistical methods and their computational implementation, models for analyzing censored data from nonrepairable systems, the traits of repairable systems and growth models, the use of expert judgment, and a review of the problem of forecasting software reliability. Specific issues addressed include the use of Bayesian methods to estimate the leak rate of a gas pipeline, approximate analyses under great prior uncertainty, reliability estimation techniques, and a nonhomogeneous Poisson process. Also addressed are the calibration sets and seed variables of expert judgment systems for risk assessment, experimental illustrations of the use of expert judgment for reliability testing, and analyses of the predictive quality of software-reliability growth models such as the Weibull order statistics.
Typing methods for legionella.
Lück, Christian; Fry, Norman K; Helbig, Jürgen H; Jarraud, Sophie; Harrison, Timothy G
2013-01-01
In this chapter we describe the methods currently used for subgrouping Legionella pneumophila and other non-pneumophila species. In the first part we describe monoclonal antibody (mAb) subgrouping, either by indirect immunofluorescence or indirect ELISA methods. These monoclonal antibodies are not commercially available but can be obtained for noncommercial purposes from one of the authors. Further, we describe pulsed-field gel electrophoresis (PFGE), amplified fragment length polymorphism (AFLP) and sequence-based typing (SBT) as well standardized and reproducible methods for genotyping. The SBT schema is currently available for L. pneumophila whereas PFGE and AFLP can be used for all Legionella species. For certain applications it might be useful to use spoligotyping to distinguish strains belonging to the same sequence type (ST). PMID:23150392
Multiple detectors "Influence Method".
Rios, I J; Mayer, R E
2016-05-01
The "Influence Method" is conceived for the absolute determination of a nuclear particle flux in the absence of known detector efficiency and without the need to register coincidences of any kind. This method exploits the influence of the presence of one detector in the count rate of another detector, when they are placed one behind the other and define statistical estimators for the absolute number of incident particles and for the efficiency (Rios and Mayer, 2015a). Its detailed mathematical description was recently published (Rios and Mayer, 2015b) and its practical implementation in the measurement of a moderated neutron flux arising from an isotopic neutron source was exemplified in (Rios and Mayer, 2016). With the objective of further reducing the measurement uncertainties, in this article we extend the method for the case of multiple detectors placed one behind the other. The new estimators for the number of particles and the detection efficiency are herein derived.
NASA Technical Reports Server (NTRS)
Pontius, James T. (Inventor)
2010-01-01
The present invention is directed to a method of bonding at least two surfaces together. The methods step of the present invention include applying a strip of adhesive to a first surface along a predefined outer boundary of a bond area and thereby defining a remaining open area there within. A second surface, or gusset plate, is affixed onto the adhesive before the adhesive cures. The strip of adhesive is allowed to cure and then a second amount of adhesive is applied to cover the remaining open area and substantially fill a void between said first and second surfaces about said bond area. A stencil may be used to precisely apply the strip of adhesive. When the strip cures, it acts as a dam to prevent overflow of the subsequent application of adhesive to undesired areas. The method results in a precise bond area free of undesired shapes and of a preferred profile which eliminate the drawbacks of the prior art bonds.
Softness perceptive texture method
NASA Astrophysics Data System (ADS)
Kobayashi, Yuichi; Suzuki, Masami; Ohya, Jun
2004-06-01
We have been studying about people's visual impression and image features for texture images in order to clarify the human subjective interpretation mechanism for images[1]. In corresponding image features of human impressions for the images, we found that the impressions for material were bottle-necked. We have studied a new analysis method which gives the impression for material from texture images. Especially, we mainly focused on the properties of visual targets which people can feel tactile sense. In this paper, we propose a new texture analysis method which is based on frequency analysis with 3D texture which is designed for photorealistic rendering. We found that our new method can estimate not only the surface roughness but also the surface softness.
NASA Astrophysics Data System (ADS)
Walczak, Beata; Daszykowski, Michał; Stanimirova, Ivana
A large progress in the development of robust methods as an efficient tool for processing of data contaminated with outlying objects has been made over the last years. Outliers in the QSAR studies are usually the result of an improper calculation of some molecular descriptors and/or experimental error in determining the property to be modelled. They influence greatly any least square model, and therefore the conclusions about the biological activity of a potential component based on such a model are misleading. With the use of robust approaches, one can solve this problem building a robust model describing the data majority well. On the other hand, the proper identification of outliers may pinpoint a new direction of a drug development. The outliers' assessment can exclusively be done with robust methods and these methods are to be described in this chapter
Multiple detectors "Influence Method".
Rios, I J; Mayer, R E
2016-05-01
The "Influence Method" is conceived for the absolute determination of a nuclear particle flux in the absence of known detector efficiency and without the need to register coincidences of any kind. This method exploits the influence of the presence of one detector in the count rate of another detector, when they are placed one behind the other and define statistical estimators for the absolute number of incident particles and for the efficiency (Rios and Mayer, 2015a). Its detailed mathematical description was recently published (Rios and Mayer, 2015b) and its practical implementation in the measurement of a moderated neutron flux arising from an isotopic neutron source was exemplified in (Rios and Mayer, 2016). With the objective of further reducing the measurement uncertainties, in this article we extend the method for the case of multiple detectors placed one behind the other. The new estimators for the number of particles and the detection efficiency are herein derived. PMID:26943904
Sparse pseudospectral approximation method
NASA Astrophysics Data System (ADS)
Constantine, Paul G.; Eldred, Michael S.; Phipps, Eric T.
2012-07-01
Multivariate global polynomial approximations - such as polynomial chaos or stochastic collocation methods - are now in widespread use for sensitivity analysis and uncertainty quantification. The pseudospectral variety of these methods uses a numerical integration rule to approximate the Fourier-type coefficients of a truncated expansion in orthogonal polynomials. For problems in more than two or three dimensions, a sparse grid numerical integration rule offers accuracy with a smaller node set compared to tensor product approximation. However, when using a sparse rule to approximately integrate these coefficients, one often finds unacceptable errors in the coefficients associated with higher degree polynomials. By reexamining Smolyak's algorithm and exploiting the connections between interpolation and projection in tensor product spaces, we construct a sparse pseudospectral approximation method that accurately reproduces the coefficients of basis functions that naturally correspond to the sparse grid integration rule. The compelling numerical results show that this is the proper way to use sparse grid integration rules for pseudospectral approximation.
Branagan, Daniel J.; Burch, Joseph V.
2001-01-01
In one aspect, the invention encompasses a method of forming a steel. A metallic glass is formed and at least a portion of the glass is converted to a crystalline steel material having a nanocrystalline scale grain size. In another aspect, the invention encompasses another method of forming a steel. A molten alloy is formed and cooled the alloy at a rate which forms a metallic glass. The metallic glass is devitrified to convert the glass to a crystalline steel material having a nanocrystalline scale grain size. In yet another aspect, the invention encompasses another method of forming a steel. A first metallic glass steel substrate is provided, and a molten alloy is formed over the first metallic glass steel substrate to heat and devitrify at least some of the underlying metallic glass of the substrate.
Barnette, Daniel W.
2002-01-01
The present invention provides a method of grid generation that uses the geometry of the problem space and the governing relations to generate a grid. The method can generate a grid with minimized discretization errors, and with minimal user interaction. The method of the present invention comprises assigning grid cell locations so that, when the governing relations are discretized using the grid, at least some of the discretization errors are substantially zero. Conventional grid generation is driven by the problem space geometry; grid generation according to the present invention is driven by problem space geometry and by governing relations. The present invention accordingly can provide two significant benefits: more efficient and accurate modeling since discretization errors are minimized, and reduced cost grid generation since less human interaction is required.
NASA Astrophysics Data System (ADS)
Hobson, Michael P.; Jaffe, Andrew H.; Liddle, Andrew R.; Mukherjee, Pia; Parkinson, David
2014-02-01
Preface; Part I. Methods: 1. Foundations and algorithms John Skilling; 2. Simple applications of Bayesian methods D. S. Sivia and Steve Rawlings; 3. Parameter estimation using Monte Carlo sampling Antony Lewis and Sarah Bridle; 4. Model selection and multi-model interference Andrew R. Liddle, Pia Mukherjee and David Parkinson; 5. Bayesian experimental design and model selection forecasting Roberto Trotta, Martin Kunz, Pia Mukherjee and David Parkinson; 6. Signal separation in cosmology M. P. Hobson, M. A. J. Ashdown and V. Stolyarov; Part II. Applications: 7. Bayesian source extraction M. P. Hobson, Graça Rocha and R. Savage; 8. Flux measurement Daniel Mortlock; 9. Gravitational wave astronomy Neil Cornish; 10. Bayesian analysis of cosmic microwave background data Andrew H. Jaffe; 11. Bayesian multilevel modelling of cosmological populations Thomas J. Loredo and Martin A. Hendry; 12. A Bayesian approach to galaxy evolution studies Stefano Andreon; 13. Photometric redshift estimation: methods and applications Ofer Lahav, Filipe B. Abdalla and Manda Banerji; Index.
NASA Astrophysics Data System (ADS)
Hobson, Michael P.; Jaffe, Andrew H.; Liddle, Andrew R.; Mukherjee, Pia; Parkinson, David
2009-12-01
Preface; Part I. Methods: 1. Foundations and algorithms John Skilling; 2. Simple applications of Bayesian methods D. S. Sivia and Steve Rawlings; 3. Parameter estimation using Monte Carlo sampling Antony Lewis and Sarah Bridle; 4. Model selection and multi-model interference Andrew R. Liddle, Pia Mukherjee and David Parkinson; 5. Bayesian experimental design and model selection forecasting Roberto Trotta, Martin Kunz, Pia Mukherjee and David Parkinson; 6. Signal separation in cosmology M. P. Hobson, M. A. J. Ashdown and V. Stolyarov; Part II. Applications: 7. Bayesian source extraction M. P. Hobson, Graça Rocha and R. Savage; 8. Flux measurement Daniel Mortlock; 9. Gravitational wave astronomy Neil Cornish; 10. Bayesian analysis of cosmic microwave background data Andrew H. Jaffe; 11. Bayesian multilevel modelling of cosmological populations Thomas J. Loredo and Martin A. Hendry; 12. A Bayesian approach to galaxy evolution studies Stefano Andreon; 13. Photometric redshift estimation: methods and applications Ofer Lahav, Filipe B. Abdalla and Manda Banerji; Index.
Unorthodox theoretical methods
Nedd, Sean
2012-01-01
The use of the ReaxFF force field to correlate with NMR mobilities of amine catalytic substituents on a mesoporous silica nanosphere surface is considered. The interfacing of the ReaxFF force field within the Surface Integrated Molecular Orbital/Molecular Mechanics (SIMOMM) method, in order to replicate earlier SIMOMM published data and to compare with the ReaxFF data, is discussed. The development of a new correlation consistent Composite Approach (ccCA) is presented, which incorporates the completely renormalized coupled cluster method with singles, doubles and non-iterative triples corrections towards the determination of heats of formations and reaction pathways which contain biradical species.
Structures and stochastic methods
Cakmak, A.S.
1987-01-01
Studies and research on structures and stochastic methods in the soil dynamics and earthquake engineering filed are covered in this book. The first section is on structures and includes studies on bridges, loaded tanks, sliding structures and wood-framed houses. The second section covers dams, retaining walls and slopes. The third section on underground structures covers pipelines, water supply, fire loss, buried lifeline, and underground transmission lines. The final section is on stochastic methods and includes applications in earthquake response spectra, lifeline aqueduct systems, and various other areas.
Smith, C.S.
1959-08-01
A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.
Mourant, J.R.; Anderson, G.D.; Bigio, I.J.; Johnson, T.M.
1996-03-12
The present invention is a method for joining hard tissue which includes chemically removing the mineral matrix from a thin layer of the surfaces to be joined, placing the two bones together, and heating the joint using electromagnetic radiation. The goal of the method is not to produce a full-strength weld of, for example, a cortical bone of the tibia, but rather to produce a weld of sufficient strength to hold the bone halves in registration while either external fixative devices are applied to stabilize the bone segments, or normal healing processes restore full strength to the tibia.
NASA Technical Reports Server (NTRS)
Schaffer, Steve; Stenger, Frank
1986-01-01
A Galerkin method using Whittaker cardinal or 'sinc' functions as basis functions is described for the solution of boundary-value problems. When the solution is analytic in the interior of the domain, the error of approximation using 2N + 1 points is O(e exp /-gamma sq rt N/) even if derivatives of the solution are singular at the boundaries. A multigrid method with overall complexity O(N log N) is used to solve the discrete equations. This paper contains a description of the multigrid-sinc algorithm along with some preliminary numerical results for two-point boundary-value problems.
Imhoff, D.H.; Harker, W.H.
1964-01-14
This patent relates to a method of producing neutrons in which there is produced a heated plasma containing heavy hydrogen isotope ions wherein heated ions are injected and confined in an elongated axially symmetric magnetic field having at least one magnetic field gradient region. In accordance with the method herein, the amplitude of the field and gradients are varied at an oscillatory periodic frequency to effect confinement by providing proper ratios of rotational to axial velocity components in the motion of said particles. The energetic neutrons may then be used as in a blanket zone containing a moderator and a source fissionable material to produce heat and thermal neutron fissionable materials. (AEC)
Electrorheological fluids and methods
Green, Peter F.; McIntyre, Ernest C.
2015-06-02
Electrorheological fluids and methods include changes in liquid-like materials that can flow like milk and subsequently form solid-like structures under applied electric fields; e.g., about 1 kV/mm. Such fluids can be used in various ways as smart suspensions, including uses in automotive, defense, and civil engineering applications. Electrorheological fluids and methods include one or more polar molecule substituted polyhedral silsesquioxanes (e.g., sulfonated polyhedral silsesquioxanes) and one or more oils (e.g., silicone oil), where the fluid can be subjected to an electric field.
NASA Astrophysics Data System (ADS)
Bardenet, Rémi
2013-07-01
Bayesian inference often requires integrating some function with respect to a posterior distribution. Monte Carlo methods are sampling algorithms that allow to compute these integrals numerically when they are not analytically tractable. We review here the basic principles and the most common Monte Carlo algorithms, among which rejection sampling, importance sampling and Monte Carlo Markov chain (MCMC) methods. We give intuition on the theoretical justification of the algorithms as well as practical advice, trying to relate both. We discuss the application of Monte Carlo in experimental physics, and point to landmarks in the literature for the curious reader.
Wong, Pak C.; Mackey, Patrick S.; Perrine, Kenneth A.; Foote, Harlan P.; Thomas, James J.
2008-12-23
Methods for visualizing a graph by automatically drawing elements of the graph as labels are disclosed. In one embodiment, the method comprises receiving node information and edge information from an input device and/or communication interface, constructing a graph layout based at least in part on that information, wherein the edges are automatically drawn as labels, and displaying the graph on a display device according to the graph layout. In some embodiments, the nodes are automatically drawn as labels instead of, or in addition to, the label-edges.
Spacecraft Attitude Determination Methods
NASA Technical Reports Server (NTRS)
Markley, F. Landis; Bauer, Frank H. (Technical Monitor)
2000-01-01
This document is presentation in viewgraph form, which outlines the methods of determining spacecraft attitude. The presentation reviews several parameterizations relating to spacecraft attitude, such as Euler's Theorem, Rodriques parameters, and Euler-Rodriques parameters or Quaternion. Onboard attitude determination is the norm, using either single frame or filtering methods. The presentation reviews several mathematical representations of attitude. The mechanisms for determining attitude on board the Hubble Space Telescope, the Tropical Rainfall and Measuring Mission and the Solar Anomalous and Magnetospheric Particle Explorer are reviewed. Wahba's problem, Procrustes Problem, and some solutions are also summarized.
Shapiro, Andrew Philip; Thornton, Roy Fred; Salvo, Joseph James
2003-01-01
The present invention provides a method for treating contaminated media. The method comprises introducing remediating ions consisting essentially of ferrous ions, and being peroxide-free, in the contaminated media; applying a potential difference across the contaminated media to cause the remediating ions to migrate into contact with contaminants in the contaminated media; chemically degrading contaminants in the contaminated media by contact with the remediating ions; monitoring the contaminated media for degradation products of the contaminants; and controlling the step of applying the potential difference across the contaminated media in response to the step of monitoring.
Hydrocarbonaceous material upgrading method
Brecher, Lee E.; Mones, Charles G.; Guffey, Frank D.
2015-06-02
A hydrocarbonaceous material upgrading method may involve a novel combination of heating, vaporizing and chemically reacting hydrocarbonaceous feedstock that is substantially unpumpable at pipeline conditions, and condensation of vapors yielded thereby, in order to upgrade that feedstock to a hydrocarbonaceous material condensate that meets crude oil pipeline specification.
NASA Astrophysics Data System (ADS)
Jackiewicz, Jason
2009-09-01
With the rapid advances in sophisticated solar modeling and the abundance of high-quality solar pulsation data, efficient and robust inversion techniques are crucial for seismic studies. We present some aspects of an efficient Fourier Optimally Localized Averaging (OLA) inversion method with an example applied to time-distance helioseismology.
Research Methods in Sociolinguistics
ERIC Educational Resources Information Center
Hernández-Campoy, Juan Manuel
2014-01-01
The development of Sociolinguistics has been qualitatively and quantitatively outstanding within Linguistic Science since its beginning in the 1950s, with a steady growth in both theoretical and methodological developments as well as in its interdisciplinary directions within the spectrum of language and society. Field methods in sociolinguistic…
NASA Technical Reports Server (NTRS)
Uspenskiy, S. I.; Yermakova, S. V.; Chaynova, L. D.; Mitkin, A. A.; Gushcheva, T. M.; Strelkov, Y. K.; Tsvetkova, N. F.
1973-01-01
Various factors used in ergonomic research are given. They are: (1) anthrometric measurement, (2) polyeffector method of assessing the functional state of man, (3) galvanic skin reaction, (4) pneumography, (5) electromyography, (6) electrooculography, and (7) tachestoscopy. A brief summary is given of each factor and includes instrumentation and results.
Biotechnology Laboratory Methods.
ERIC Educational Resources Information Center
Davis, Robert H.; Kompala, Dhinakar S.
1989-01-01
Describes a course entitled "Biotechnology Laboratory" which introduces a variety of laboratory methods associated with biotechnology. Describes the history, content, and seven experiments of the course. The seven experiments are selected from microbiology and molecular biology, kinetics and fermentation, and downstream processing-bioseparations.…
2012-08-01
Interatomic force and energy calculation subroutine to be used with the molecular dynamics simulation code LAMMPS (Ref a.). The code evaluated the total energy and atomic forces (energy gradient) according to a cubic spline-based variant (Ref b.) of the Modified Embedded Atom Method (MEAM) with a additional Stillinger-Weber (SW) contribution.
Implementing Cooperative Learning Methods.
ERIC Educational Resources Information Center
Lyons, Paul R.
This paper identifies the bases and rationale for the concept of cooperative learning; describes the dynamics of the cooperative learning approach; and proposes methods that college faculty can use to enhance student motivation and learning. Cooperative learning is defined and is reported to have positive effects on student achievement, human…
Collins, H. Dale; Gribble, R. Parks; Busse, Lawrence J.
1991-01-01
A method for providing an image of the human heart's electrical system derives time-of-flight data from an array of EKG electrodes and this data is transformed into phase information. The phase information, treated as a hologram, is reconstructed to provide an image in one or two dimensions of the electrical system of the functioning heart.
Projecting the Scientific Method.
ERIC Educational Resources Information Center
Uthe, R. E.
2000-01-01
Describes how the gas laws are an excellent vehicle for introducing the steps of the scientific method. Students can use balloons and a simple apparatus to observe changes in various gas parameters, develop ideas about the changes they see, collect numerical data, test their ideas, derive simple equations for the relationships, and use the…
Methods of making pyrrolidones
Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.
2004-03-16
The present invention provides methods for making N-methylpyrrolidine and analogous compounds via hydrogenation. Novel catalysts for this process, and novel conditions/yields are also described. Other process improvements may include extraction and hydrolysis steps. Some preferred reactions take place in the aqueous phase. Starting materials for making N-methylpyrrolidine may include succinic acid, N-methylsuccinimide, and their analogs.
Methods of making pyrrolidones
Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.
2003-10-14
The present invention provides methods for making N-methylpyrrolidine and analogous compounds via hydrogenation. Novel catalysts for this process, and novel conditions/yields are also described. Other process improvements may include extraction and hydrolysis steps. Some preferred reactions take place in the aqueous phase. Starting materials for making N-methylpyrrolidine may include succinic acid, N-methylsuccinimide, and their analogs.
Methods Of Making Pyrrolidones
Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.
2003-12-30
The present invention provides methods for making N-methylpyrrolidine and analogous compounds via hydrogenation. Novel catalysts for this process, and novel conditions/yields are also described. Other process improvements may include extraction and hydrolysis steps. Some preferred reactions take place in the aqueous phase. Starting materials for making N-methylpyrrolidine may include succinic acid, N-methylsuccinimide, and their analogs.
Methods of making pyrrolidones
Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.
2003-08-05
The present invention provides methods for making N-methylpyrrolidine and analogous compounds via hydrogenation. Novel catalysts for this process, and novel conditions/yields are also described. Other process improvements may include extraction and hydrolysis steps. Some preferred reactions take place in the aqueous phase. Starting materials for making N-methylpyrrolidine may include succinic acid, N-methylsuccinimide, and their analogs.
Friend, Julie; Elander, Richard T.; Tucker, III; Melvin P.; Lyons, Robert C.
2010-10-26
A method for treating biomass was developed that uses an apparatus which moves a biomass and dilute aqueous ammonia mixture through reaction chambers without compaction. The apparatus moves the biomass using a non-compressing piston. The resulting treated biomass is saccharified to produce fermentable sugars.
NASA Technical Reports Server (NTRS)
Gayman, W. H.
1974-01-01
Test method and apparatus determine fluid effective mass and damping in frequency range where effective mass may be considered as total mass less sum of slosh masses. Apparatus is designed so test tank and its mounting yoke are supported from structural test wall by series of flexures.
Ferrari's Method and Technology
ERIC Educational Resources Information Center
Althoen, Steve
2005-01-01
Some tips that combine knowledge of mathematics history and technology for adapting Ferrar's method to factor quintics with a TI-83 graphing calculator are presented. A demonstration on the use of the root finder and regression capabilities of the graphing calculator are presented, so that the tips can be easily adapted for any graphing calculator…
Photovoltaic device and method
Cleereman, Robert J; Lesniak, Michael J; Keenihan, James R; Langmaid, Joe A; Gaston, Ryan; Eurich, Gerald K; Boven, Michelle L
2015-01-27
The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.
Jackiewicz, Jason
2009-09-16
With the rapid advances in sophisticated solar modeling and the abundance of high-quality solar pulsation data, efficient and robust inversion techniques are crucial for seismic studies. We present some aspects of an efficient Fourier Optimally Localized Averaging (OLA) inversion method with an example applied to time-distance helioseismology.
Photovoltaic device and method
Cleereman, Robert; Lesniak, Michael J.; Keenihan, James R.; Langmaid, Joe A.; Gaston, Ryan; Eurich, Gerald K.; Boven, Michelle L.
2015-11-24
The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.
Kong, Peter C.; Pink, Robert J.; Zuck, Larry D.
2008-08-19
A method for forming ammonia is disclosed and which includes the steps of forming a plasma; providing a source of metal particles, and supplying the metal particles to the plasma to form metal nitride particles; and providing a substance, and reacting the metal nitride particles with the substance to produce ammonia, and an oxide byproduct.
Lipp, G. Daniel
1994-05-03
A method and die apparatus for manufacturing a honeycomb body of triangular cell cross-section and high cell density, the die having a combination of (i) feedholes feeding slot intersections and (ii) feedholes feeding slot segments not supplied from slot intersections, whereby a reduction in feedhole count is achieved while still retaining good extrusion efficiency and extrudate uniformity.
Teaching Materials and Methods.
ERIC Educational Resources Information Center
Physiologist, 1982
1982-01-01
Twelve abstracts of papers presented at the 33rd Annual Fall Meeting of the American Physiological Society are listed, focusing on teaching materials/methods. Topics, among others, include trends in physiology laboratory programs, cardiovascular system model, cardiovascular computer simulation with didactic feedback, and computer generated figures…
ERIC Educational Resources Information Center
Thomson, Bill
The basic principles and techniques of soccer are explained and illustrated with photographs and diagrams to aid teachers who are introducing soccer into the physical education curriculum. In addition, it is designed to guide youth soccer coaches who wish to improve their presentations. The book discusses: (1) coaching methods; (2) passing and…
Method of purifying isosaccharinate
Rai, Dhanpat; Moore, Robert C.; Tucker, Mark D.
2010-09-07
A method of purifying isosaccharinate by mixing sodium carbonate, potassium carbonate, sodium hydroxide or potassium hydroxide with calcium isosaccharinate, removing the precipitated calcium carbonate and adjusting the pH to between approximately 4.5 to 5.0 thereby removing excess carbonate and hydroxide to provide an acidic solution containing isosaccharinate.
ERIC Educational Resources Information Center
Pinar, William Frederick
In this presentation the author paints a conceptual portrait of his evolving relationships to his formal studies and thereby describes a method by which educators can reconceptualize the meaning of curriculum. By taking oneself and one's existential experience as a data source and using the psychoanalytical technique of free association, one can…
Banker, John G.; Holcombe, Jr., Cressie E.
1977-01-01
A method of limiting carbon contamination from graphite ware used in induction melting of uranium alloys is provided comprising coating the graphite surface with a suspension of Y.sub.2 O.sub.3 particles in water containing about 1.5 to 4% by weight sodium carboxymethylcellulose.
Nevanlinna, O.
1994-12-31
This note summarizes some results on (a monitored version of) the Arnoldi method in Hilbert spaces. The interest in working in infinite dimensional spaces comes partly from the fact that only then can one have meaningful asymptotical statements (which hopefully give some light to the convergence of Arnoldi in large dimensional problems with iteration indices far less than the dimension).
NASA Astrophysics Data System (ADS)
Kuksin, Sergei; Maiocchi, Alberto
In this chapter we present a general method of constructing the effective equation which describes the behavior of small-amplitude solutions for a nonlinear PDE in finite volume, provided that the linear part of the equation is a hamiltonian system with a pure imaginary discrete spectrum. The effective equation is obtained by retaining only the resonant terms of the nonlinearity (which may be hamiltonian, or may be not); the assertion that it describes the limiting behavior of small-amplitude solutions is a rigorous mathematical theorem. In particular, the method applies to the three- and four-wave systems. We demonstrate that different possible types of energy transport are covered by this method, depending on whether the set of resonances splits into finite clusters (this happens, e.g. in case of the Charney-Hasegawa-Mima equation), or is connected (this happens, e.g. in the case of the NLS equation if the space-dimension is at least two). For equations of the first type the energy transition to high frequencies does not hold, while for equations of the second type it may take place. Our method applies to various weakly nonlinear wave systems, appearing in plasma, meteorology and oceanography.
ERIC Educational Resources Information Center
GILBERT, HARRY B.; LANG, GERHARD
THIS REPORT OF A TWO-DAY CONFERENCE ON TEACHER SELECTION METHODS, ATTENDED BY 45 EXPERTS IN THE FIELD, CONTAINS 13 POSITION PAPERS DEALING WITH (1) PERSONNEL SELECTION IN NON-TEACHING FIELDS, (2) PROBLEMS IN TEACHER SELECTION, RECRUITMENT AND IN VALIDATION OF SELECTION PROCEDURES, AND (3) NEEDED RESEARCH IN TEACHER SELECTION--ALSO CONFERENCE…
METHOD OF CENTRIFUGE OPERATION
Cohen, K.
1960-05-10
A method of isotope separation is described in which two streams are flowed axially of, and countercurrently through, a cylindrical centrifuge bowl. Under the influence of a centrifugal field, the light fraction is concentrated in a stream flowing through the central portion of the bowl, whereas the heavy fraction is concentrated in a stream at the periphery thereof.
ERIC Educational Resources Information Center
Schechter, Abraham A.
This book addresses some common preservation techniques that invariably become necessary in library and archival collections of any size. The procedures are described in chronological sequence, and photographs show the techniques from the viewpoint of the person actually doing the work. The recommended repair methods can be accomplished using…
Banker, J.G.; Holcombe, C.E. Jr.
1975-11-06
A method of limiting carbon contamination from graphite ware used in induction melting of uranium alloys is provided. The graphite surface is coated with a suspension of Y/sub 2/O/sub 3/ particles in water containing about 1.5 to 4 percent by weight sodium carboxymethylcellulose.
Method of photocatalytic nanotagging
Shelnutt, John A.; Medforth, Craig J.; Song, Yujiang
2010-04-27
A nanotagged chemical structure comprising a chemical structure with an associated photocatalyst and a tagging nanoparticle (a nanotag) grown in proximity to the photocatalyst, and a method for making the nanotagged chemical structure. The nanoparticle is grown in proximity to the photocatalyst by using a photocatalytic reduction reaction.
Weissmann, Charles
2013-11-01
Major advances in science are usually launched by new methods or techniques. Because this essay is not intended as a history of science, I shall not invoke the invention of the microscope or telescope as the gateways to inner and outer space, but will restrict myself to developments I have witnessed, or almost witnessed, during my scientific lifetime. PMID:24055872
Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee
2013-04-16
The present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit.
High efficiency telemetry method
NASA Technical Reports Server (NTRS)
Lim, L. Y.
1971-01-01
Analog and digital mechanizations contain new combinations of known circuits that generate coefficients of Fourier series terms in accordance with harmonic content of waveform to be transmitted. Technique represents information signal more accurately that previous methods and requires fewer information bits.
ERIC Educational Resources Information Center
Dasenbrock, Reed Way
1995-01-01
Examines literary theory's displacing of "method" in the New Historicist criticism. Argues that Stephen Greenblatt and Lee Paterson imply that no objective historical truth is possible and as a result do not give methodology its due weight in their criticism. Questions the theory of "truth" advanced in this vein of literary criticism. (TB)
Healy, Richard W.; Scanlon, Bridget R.
2010-01-01
A water budget is an accounting of water movement into and out of, and storage change within, some control volume. Universal and adaptable are adjectives that reflect key features of water-budget methods for estimating recharge. The universal concept of mass conservation of water implies that water-budget methods are applicable over any space and time scales (Healy et al., 2007). The water budget of a soil column in a laboratory can be studied at scales of millimeters and seconds. A water-budget equation is also an integral component of atmospheric general circulation models used to predict global climates over periods of decades or more. Water-budget equations can be easily customized by adding or removing terms to accurately portray the peculiarities of any hydrologic system. The equations are generally not bound by assumptions on mechanisms by which water moves into, through, and out of the control volume of interest. So water-budget methods can be used to estimate both diffuse and focused recharge, and recharge estimates are unaffected by phenomena such as preferential flow paths within the unsaturated zone. Water-budget methods represent the largest class of techniques for estimating recharge. Most hydrologic models are derived from a water-budget equation and can therefore be classified as water-budget models. It is not feasible to address all water-budget methods in a single chapter. This chapter is limited to discussion of the “residual” water-budget approach, whereby all variables in a water-budget equation, except for recharge, are independently measured or estimated and recharge is set equal to the residual. This chapter is closely linked with Chapter 3, on modeling methods, because the equations presented here form the basis of many models and because models are often used to estimate individual components in water-budget studies. Water budgets for streams and other surface-water bodies are addressed in Chapter 4. The use of soil-water budgets and
Nonhazardous Urine Pretreatment Method
NASA Technical Reports Server (NTRS)
Akse, James R.; Holtsnider, John T.
2012-01-01
A method combines solid phase acidification with two non-toxic biocides to prevent ammonia volatilization and microbial proliferation. The safe, non-oxidizing biocide combination consists of a quaternary amine and a food preservative. This combination has exhibited excellent stabilization of both acidified and unacidified urine. During pretreatment tests, composite urine collected from donors was challenged with a microorganism known to proliferate in urine, and then was processed using the nonhazardous urine pre-treatment method. The challenge microorganisms included Escherichia coli, a common gram-negative bacteria; Enterococcus faecalis, a ureolytic gram-positive bacteria; Candida albicans, a yeast commonly found in urine; and Aspergillus niger, a problematic mold that resists urine pre-treatment. Urine processed in this manner remained microbially stable for over 57 days. Such effective urine stabilization was achieved using non-toxic, non-oxidizing biocides at higher pH (3.6 to 5.8) than previous methods in use or projected for use aboard the International Space Station (ISS). ISS urine pretreatment methods employ strong oxidants including ozone and hexavalent chromium (Cr(VI)), a carcinogenic material, under very acidic conditions (pH = 1.8 to 2.4). The method described here offers a much more benign chemical environment than previous pretreatment methods, and will lower equivalent system mass (ESM) by reducing containment volume and mass, system complexity, and crew time needed to handle pre-treatment chemicals. The biocides, being non-oxidizing, minimize the potential for chemical reactions with urine constituents to produce volatile, airborne contaminants such as cyanogen chloride. Additionally, the biocides are active under significantly less acidic conditions than those used in the current system, thereby reducing the degree of required acidification. A simple flow-through solid phase acidification (SPA) bed is employed to overcome the natural buffering
Aeroelastic analysis of a troposkien-type wind turbine blade
NASA Technical Reports Server (NTRS)
Nitzsche, F.
1981-01-01
The linear aeroelastic equations for one curved blade of a vertical axis wind turbine in state vector form are presented. The method is based on a simple integrating matrix scheme together with the transfer matrix idea. The method is proposed as a convenient way of solving the associated eigenvalue problem for general support conditions.
Smith, Richard Harding; Martin, Glenn Brian
2004-05-18
The present invention allows the determination of trace levels of ionic substances in a sample solution (ions, metal ions, and other electrically charged molecules) by coupling a separation method, such as liquid chromatography, with ion selective electrodes (ISE) prepared so as to allow detection at activities below 10.sup.-6 M. The separation method distributes constituent molecules into fractions due to unique chemical and physical properties, such as charge, hydrophobicity, specific binding interactions, or movement in an electrical field. The separated fractions are detected by means of the ISE(s). These ISEs can be used singly or in an array. Accordingly, modifications in the ISEs are used to permit detection of low activities, specifically, below 10.sup.-6 M, by using low activities of the primary analyte (the molecular species which is specifically detected) in the inner filling solution of the ISE. Arrays constructed in various ways allow flow-through sensing for multiple ions.
Chen, Jack C.; Stawisuck, Valerie M.; Prasad, Ravi
2003-01-01
A cold isopressing method in which two or more layers of material are formed within an isopressing mold. One of the layers consists of a tape-cast film. The layers are isopressed within the isopressing mold, thereby to laminate the layers and to compact the tape-cast film. The isopressing mold can be of cylindrical configuration with the layers being coaxial cylindrical layers. The materials used in forming the layers can contain green ceramic materials and the resultant structure can be fired and sintered as necessary and in accordance with known methods to produce a finished composite, ceramic structure. Further, such green ceramic materials can be of the type that are capable of conducting hydrogen or oxygen ions at high temperature with the object of utilizing the finished composite ceramic structure as a ceramic membrane element.
Proximal Point Methods Revisited
NASA Astrophysics Data System (ADS)
Boikanyo, Oganeditse A.; Moroşanu, Gheorghe
2011-09-01
The proximal point methods have been widely used in the last decades to approximate the solutions of nonlinear equations associated with monotone operators. Inspired by the iterative procedure defined by B. Martinet (1970), R.T. Rockafellar introduced in 1976 the so-called proximal point algorithm (PPA) for a general maximal monotone operator. The sequence generated by this iterative method is weakly convergent under appropriate conditions, but not necessarily strongly convergent, as proved by O. Güler (1991). This fact explains the introduction of different modified versions of the PPA which generate strongly convergent sequences under appropriate conditions, including the contraction-PPA defined by H.K. Xu in 2002. Here we discuss Xu's modified PPA as well as some of its generalizations. Special attention is paid to the computational errors, in particular the original Rockafellar summability assumption is replaced by the condition that the error sequence converges to zero strongly.
Automatic transmission control method
Hasegawa, H.; Ishiguro, T.
1989-07-04
This patent describes a method of controlling an automatic transmission of an automotive vehicle. The transmission has a gear train which includes a brake for establishing a first lowest speed of the transmission, the brake acting directly on a ring gear which meshes with a pinion, the pinion meshing with a sun gear in a planetary gear train, the ring gear connected with an output member, the sun gear being engageable and disengageable with an input member of the transmission by means of a clutch. The method comprises the steps of: detecting that a shift position of the automatic transmission has been shifted to a neutral range; thereafter introducing hydraulic pressure to the brake if present vehicle velocity is below a predetermined value, whereby the brake is engaged to establish the first lowest speed; and exhausting hydraulic pressure from the brake if present vehicle velocity is higher than a predetermined value, whereby the brake is disengaged.
Juric, R.
1996-12-31
Any methodology for information systems development defines rules and conditions that are to be followed and satisfied when applying it to developing analysis and design models of a system. The newest attempt to achieve a successful systems development and establish standards in object oriented analysis and design technologies resulted in the unified method documentation set, version 0.8 being published in late 1995. In this paper I will analyse the first draft and present a set of rules that must be satisfied by the valid unified method. The rules are divided into different sections: (A) classes/objects and categories, (B) attributes and operations, (C) associations and inheritance, (D) message trace diagram/object message diagram/state diagram/use cases.
Strong-Gunderson, J.M.; Palumbo, A.V.
1998-09-15
The present invention is a biological tracer method for characterizing the movement of a material through a medium, comprising the steps of: introducing a biological tracer comprising a microorganism having ice nucleating activity into a medium; collecting at least one sample of the medium from a point removed from the introduction point; and analyzing the sample for the presence of the biological tracer. The present invention is also a method for using a biological tracer as a label for material identification by introducing a biological tracer having ice nucleating activity into a material, collecting a sample of a portion of the labelled material and analyzing the sample for the presence of the biological tracer. 2 figs.
Strong-Gunderson, Janet M.; Palumbo, Anthony V.
1998-01-01
The present invention is a biological tracer method for characterizing the movement of a material through a medium, comprising the steps of: introducing a biological tracer comprising a microorganism having ice nucleating activity into a medium; collecting at least one sample of the medium from a point removed from the introduction point; and analyzing the sample for the presence of the biological tracer. The present invention is also a method for using a biological tracer as a label for material identification by introducing a biological tracer having ice nucleating activity into a material, collecting a sample of a portion of the labelled material and analyzing the sample for the presence of the biological tracer.
Nanoscale waveguiding methods.
Wang, Chia-Jean; Lin, Lih Y
2007-05-01
While 32 nm lithography technology is on the horizon for integrated circuit (IC) fabrication, matching the pace for miniaturization with optics has been hampered by the diffraction limit. However, development of nanoscale components and guiding methods is burgeoning through advances in fabrication techniques and materials processing. As waveguiding presents the fundamental issue and cornerstone for ultra-high density photonic ICs, we examine the current state of methods in the field. Namely, plasmonic, metal slot and negative dielectric based waveguides as well as a few sub-micrometer techniques such as nanoribbons, high-index contrast and photonic crystals waveguides are investigated in terms of construction, transmission, and limitations. Furthermore, we discuss in detail quantum dot (QD) arrays as a gain-enabled and flexible means to transmit energy through straight paths and sharp bends. Modeling, fabrication and test results are provided and show that the QD waveguide may be effective as an alternate means to transfer light on sub-diffraction dimensions.
Comprehensive rotorcraft analysis methods
NASA Technical Reports Server (NTRS)
Stephens, Wendell B.; Austin, Edward E.
1988-01-01
The development and application of comprehensive rotorcraft analysis methods in the field of rotorcraft technology are described. These large scale analyses and the resulting computer programs are intended to treat the complex aeromechanical phenomena that describe the behavior of rotorcraft. They may be used to predict rotor aerodynamics, acoustic, performance, stability and control, handling qualities, loads and vibrations, structures, dynamics, and aeroelastic stability characteristics for a variety of applications including research, preliminary and detail design, and evaluation and treatment of field problems. The principal comprehensive methods developed or under development in recent years and generally available to the rotorcraft community because of US Army Aviation Research and Technology Activity (ARTA) sponsorship of all or part of the software systems are the Rotorcraft Flight Simulation (C81), Dynamic System Coupler (DYSCO), Coupled Rotor/Airframe Vibration Analysis Program (SIMVIB), Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD), General Rotorcraft Aeromechanical Stability Program (GRASP), and Second Generation Comprehensive Helicopter Analysis System (2GCHAS).
Fox, Robert V.; Zhang, Fengyan; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin
2016-06-21
Single source precursors or pre-copolymers of single source precursors are subjected to microwave radiation to form particles of a I-III-VI.sub.2 material. Such particles may be formed in a wurtzite phase and may be converted to a chalcopyrite phase by, for example, exposure to heat. The particles in the wurtzite phase may have a substantially hexagonal shape that enables stacking into ordered layers. The particles in the wurtzite phase may be mixed with particles in the chalcopyrite phase (i.e., chalcopyrite nanoparticles) that may fill voids within the ordered layers of the particles in the wurtzite phase thus produce films with good coverage. In some embodiments, the methods are used to form layers of semiconductor materials comprising a I-III-VI.sub.2 material. Devices such as, for example, thin-film solar cells may be fabricated using such methods.
NASA Astrophysics Data System (ADS)
Wang, Chia-Jean; Lin, Lih Y.
2007-05-01
While 32 nm lithography technology is on the horizon for integrated circuit (IC) fabrication, matching the pace for miniaturization with optics has been hampered by the diffraction limit. However, development of nanoscale components and guiding methods is burgeoning through advances in fabrication techniques and materials processing. As waveguiding presents the fundamental issue and cornerstone for ultra-high density photonic ICs, we examine the current state of methods in the field. Namely, plasmonic, metal slot and negative dielectric based waveguides as well as a few sub-micrometer techniques such as nanoribbons, high-index contrast and photonic crystals waveguides are investigated in terms of construction, transmission, and limitations. Furthermore, we discuss in detail quantum dot (QD) arrays as a gain-enabled and flexible means to transmit energy through straight paths and sharp bends. Modeling, fabrication and test results are provided and show that the QD waveguide may be effective as an alternate means to transfer light on sub-diffraction dimensions.
Motor degradation prediction methods
Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.
1996-12-01
Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.
Swiler, Thomas P [Albuquerque, NM; Garcia, Ernest J [Albuquerque, NM; Francis, Kathryn M [Rio Rancho, NM
2014-01-07
A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with a HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die.
Swiler, Thomas P.; Garcia, Ernest J.; Francis, Kathryn M.
2013-06-11
A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with an HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die.
Inspection system calibration methods
Deason, Vance A.; Telschow, Kenneth L.
2004-12-28
An inspection system calibration method includes producing two sideband signals of a first wavefront; interfering the two sideband signals in a photorefractive material, producing an output signal therefrom having a frequency and a magnitude; and producing a phase modulated operational signal having a frequency different from the output signal frequency, a magnitude, and a phase modulation amplitude. The method includes determining a ratio of the operational signal magnitude to the output signal magnitude, determining a ratio of a 1st order Bessel function of the operational signal phase modulation amplitude to a 0th order Bessel function of the operational signal phase modulation amplitude, and comparing the magnitude ratio to the Bessel function ratio.
Dixon, R.D.; Smith, F.M.; O`Leary, R.F.
1995-12-31
A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. Beryllium parts made using this method can be used as structural components in aircraft, satellites and space applications.
Baillie, L.A.; Senese, F.J.
1988-09-27
This patent describes a method for determining leaks in a storage tank containing a liquid. The method consists of: locating a float means initially at a depth in the liquid approximately equal to V/sub L//S/sub L/ where V/sub L/ is the volume of the liquid in the tank and S/sub L/ is free surface area of the liquid in the tank; saturating vapor above the liquid in the tank with vapor of the liquid by atomizing so as to fill the vapor above the liquid with small drops of liquid or coating surfaces of the tank above the liquid with a thin layer of the liquid so as to hasten saturation of the vapor above the liquid, so that temperature variation of the liquid in the tank does not change the depth at which the float means floats in the liquid; and determining changes of location of the float means in the tank.
RUTHENIUM DECONTAMINATION METHOD
Gresky, A.T.
1960-07-19
A liquid-liquid extraction method of separating uranium from fission products is given. A small amount of a low molecular weight ketone is added to an acidic aqueous solution containing neutron-irradiated uranium and its associated fission products. The resulting solution is digested and then contacted with an organic liquid that extracts uranium values. The purpose of the step of digesting the aqueous solution in the presence of the ketone is to suppress the extractability of ruthenium.
Poco, J.F.
1993-09-07
The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm[sup 3] to 0.6 g/cm[sup 3]. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of aerogel which occurs during the drying step of supercritical extraction of solvent. 2 figures.
Sithambaram, Shanthakumar; Son, Young-Chan; Suib, Steven L.
2008-04-08
A method for forming an imine comprises reacting a first reactant comprising a hydroxyl functionality, a carbonyl functionality, or both a hydroxyl functionality and a carbonyl functionality with a second reactant having an amine functionality in the presence of ordered porous manganese-based octahedral molecular sieves and an oxygen containing gas at a temperature and for a time sufficient for the imine to be produced.
Mathematical Methods for Physicists
NASA Astrophysics Data System (ADS)
Chow, Tai L.
2000-07-01
Preface; 1. Vector and tensor analysis; 2. Ordinary differential equations; 3. Matrix algebra; 4. Fourier series and integrals; 5. Linear vector spaces; 6. Functions of a complex variable; 7. Special functions of mathematical physics; 8. The calculus of variations; 9. The Laplace transformation; 10. Partial differential equations; 11. Simple linear integral equations; 12. Elements of group theory; 13. Numerical methods; 14. Introduction to probability theory; Appendices; Further reading; Index.
Bianchini, Gregory M.; McRae, Thomas G.
1985-01-01
Method for continuous sampling of liquified natural gas effluent from a spill pipe, vaporizing the cold liquified natural gas, and feeding the vaporized gas into an infrared detector to measure the gas composition. The apparatus utilizes a probe having an inner channel for receiving samples of liquified natural gas and a surrounding water jacket through which warm water is flowed to flash vaporize the liquified natural gas.
NASA Technical Reports Server (NTRS)
Chang-Diaz, Franklin R. (Inventor)
1989-01-01
Apparatus and method of removing desirable constituents from an infusible material by infusion extraction, where a piston operating in a first chamber draws a solvent into the first chamber where it may be heated, and then moves the heated solvent into a second chamber containing the infusible material, and where infusion extraction takes place. The piston then moves the solvent containing the extract through a filter into the first chamber, leaving the extraction residue in the second chamber.
Kato, Akio
2006-11-14
The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.
Lipp, G. Daniel
1994-04-26
A method and die apparatus for manufacturing a honeycomb body of rhombic cell cross-section by extrusion through an extrusion die of triangular cell discharge slot configuration, the die incorporating feedholes at selected slot intersections only, such that slot segments communicating directly with the feedholes discharge web material and slot segments not so connected do not discharge web material, whereby a rhombic cell cross-section in the extruded body is provided.
Geometrical method of decoupling
NASA Astrophysics Data System (ADS)
Baumgarten, C.
2012-12-01
The computation of tunes and matched beam distributions are essential steps in the analysis of circular accelerators. If certain symmetries—like midplane symmetry—are present, then it is possible to treat the betatron motion in the horizontal, the vertical plane, and (under certain circumstances) the longitudinal motion separately using the well-known Courant-Snyder theory, or to apply transformations that have been described previously as, for instance, the method of Teng and Edwards. In a preceding paper, it has been shown that this method requires a modification for the treatment of isochronous cyclotrons with non-negligible space charge forces. Unfortunately, the modification was numerically not as stable as desired and it was still unclear, if the extension would work for all conceivable cases. Hence, a systematic derivation of a more general treatment seemed advisable. In a second paper, the author suggested the use of real Dirac matrices as basic tools for coupled linear optics and gave a straightforward recipe to decouple positive definite Hamiltonians with imaginary eigenvalues. In this article this method is generalized and simplified in order to formulate a straightforward method to decouple Hamiltonian matrices with eigenvalues on the real and the imaginary axis. The decoupling of symplectic matrices which are exponentials of such Hamiltonian matrices can be deduced from this in a few steps. It is shown that this algebraic decoupling is closely related to a geometric “decoupling” by the orthogonalization of the vectors E→, B→, and P→, which were introduced with the so-called “electromechanical equivalence.” A mathematical analysis of the problem can be traced down to the task of finding a structure-preserving block diagonalization of symplectic or Hamiltonian matrices. Structure preservation means in this context that the (sequence of) transformations must be symplectic and hence canonical. When used iteratively, the decoupling
Johns, I.B.; Newton, A.S.
1958-09-01
A method is described for detecting pin hole imperfections in coatings on uranium-metal objects. Such coated objects are contacted with a heated atmosphere of gaseous hydrogen and imperfections present in the coatings will allow the uranlum to react with the hydrogen to form uranium hydride. Since uranium hydride is less dense than uranium metal it will swell, causing enlargement of the coating defeot and rendering it visible.
Polymer compositions and methods
Allen, Scott D.; Willkomm, Wayne R.
2016-09-27
The present invention encompasses polyurethane compositions comprising aliphatic polycarbonate chains. In one aspect, the present invention encompasses polyurethane foams, thermoplastics and elastomers derived from aliphatic polycarbonate polyols and polyisocyanates wherein the polyol chains contain a primary repeating unit having a structure: ##STR00001## In another aspect, the invention provides articles comprising the inventive foam and elastomer compositions as well as methods of making such compositions.
Method for making nanomaterials
Fan, Hongyou; Wu, Huimeng
2013-06-04
A method of making a nanostructure by preparing a face centered cubic-ordered metal nanoparticle film from metal nanoparticles, such as gold and silver nanoparticles, exerting a hydrostatic pressure upon the film at pressures of several gigapascals, followed by applying a non-hydrostatic stress perpendicularly at a pressure greater than approximately 10 GPA to form an array of nanowires with individual nanowires having a relatively uniform length, average diameter and density.
NASA Technical Reports Server (NTRS)
Holt, Maurice
1996-01-01
In this paper, second order Godunov methods are reviewed. The early versions by Colella and Woodward (PPM) and van Leer (MUSCL) are described in their original form. The simplification of these by Roe, based on approximate Riemann solver, is then presented. Attention is next given to the improvement in MUSCL due to Hancock and van Leer leading to a fuller paper by Huynh. Finally, brief reference is made to TVD and ENO schemes due to Harten.
Poco, John F.
1993-01-01
The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm.sup.3 to 0.6 g/cm.sup.3. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of alcogel which occurs during the drying step of supercritical extraction of solvent.
METHOD OF SEPARATING PLUTONIUM
Heal, H.G.
1960-02-16
BS>A method of separating plutonium from aqueous nitrate solutions of plutonium, uranium. and high beta activity fission products is given. The pH of the aqueous solution is adjusted between 3.0 to 6.0 with ammonium acetate, ferric nitrate is added, and the solution is heated to 80 to 100 deg C to selectively form a basic ferric plutonium-carrying precipitate.
Chang, Shih-ger; Liu, Shou-heng; Liu, Zhao-rong; Yan, Naiqiang
2009-01-20
Disclosed herein is a method for removing mercury from a gas stream comprising contacting the gas stream with a getter composition comprising bromine, bromochloride, sulphur bromide, sulphur dichloride or sulphur monochloride and mixtures thereof. In one preferred embodiment the getter composition is adsorbed onto a sorbent. The sorbent may be selected from the group consisting of flyash, limestone, lime, calcium sulphate, calcium sulfite, activated carbon, charcoal, silicate, alumina and mixtures thereof. Preferred is flyash, activated carbon and silica.
Chang, Shih-ger; Liu, Shou-heng; Liu, Zhao-rong; Yan, Naiqiang
2010-07-13
Disclosed herein is a method for removing mercury from a gas stream comprising contacting the gas stream with a getter composition comprising bromine, bromochloride, sulphur bromide, sulphur dichloride or sulphur monochloride and mixtures thereof. In one preferred embodiment the getter composition is adsorbed onto a sorbent. The sorbent may be selected from the group consisting flyash, limestone, lime, calcium sulphate, calcium sulfite, activated carbon, charcoal, silicate, alumina and mixtures thereof. Preferred is flyash, activated carbon and silica.
Chang, Shih-Ger; Liu, Shou-Heng; Liu, Zhao-Rong; Yan, Naiqiang
2011-08-30
Disclosed herein is a method for removing mercury from a gas stream comprising contacting the gas stream with a getter composition comprising bromine, bromochloride, sulphur bromide, sulphur dichloride or sulphur monochloride and mixtures thereof. In one preferred embodiment the getter composition is adsorbed onto a sorbent. The sorbent may be selected from the group consisting of flyash, limestone, lime, calcium sulphate, calcium sulfite, activated carbon, charcoal, silicate, alumina and mixtures thereof. Preferred is flyash, activated carbon and silica.
Kertesz, F.; Buttram, H.J.
1962-04-24
ABS>A method for impregnating a refractory material by filling its pores with a first salt having a high melting temperature is described. The salt is mixed with another, more volatile salt, giving the mixture a much lower melting temperature than that of the first salt. The material is coated with the mixture, then heated to drive off the volatile salt, leaving the first salt in place. (AEC)
Method for detecting biomolecules
Huo, Qisheng; Liu, Jun
2008-08-12
A method for detecting and measuring the concentration of biomolecules in solution, utilizing a conducting electrode in contact with a solution containing target biomolecules, with a film with controllable pore size distribution characteristics applied to at least one surface of the conducting electrode. The film is functionalized with probe molecules that chemically interact with the target biomolecules at the film surface, blocking indicator molecules present in solution from diffusing from the solution to the electrode, thereby changing the electrochemical response of the electrode
NASA Technical Reports Server (NTRS)
Chen, J.-Y.
1992-01-01
Viewgraphs are presented on the following topics: the grand challenge of combustion engineering; research of probability density function (PDF) methods at Sandia; experiments of turbulent jet flames (Masri and Dibble, 1988); departures from chemical equilibrium; modeling turbulent reacting flows; superequilibrium OH radical; pdf modeling of turbulent jet flames; scatter plot for CH4 (methane) and O2 (oxygen); methanol turbulent jet flames; comparisons between predictions and experimental data; and turbulent C2H4 jet flames.
Innovative sludge stabilization method
Riggenbach, J.D.
1995-06-01
Sludge is generated in many water and wastewater treatment processes, both biological and physical/chemical. Examples include biological sludges from sanitary and industrial wastewater treatment operations and chemical sludges such as those produced when metals are removed from metal plating wastewater. Even some potable water plants produce sludge, such as when alum is used as a flocculating agent to clarify turbid water. Because sludge is produced from such a variety of operations, different techniques have been developed to remove water from sludges and reduce the sludge volume and mass, thus making the sludge more suitable for recovery or disposal. These techniques include mechanical (e.g., filter presses), solar (sludge drying beds), and thermal. The least expensive of these methods, neglecting land costs, involves sludge drying beds and lagoons. The solar method was widely used in sewage treatment plants for many years, but has fallen in disfavor in the US; mechanical and thermal methods have been preferred. Since environmental remediation often requires managing sludges, this article presents a discussion of a variation of sludge lagoons known as evaporative sludge stabilization. Application of this process to the closure of two 2.5 acre (10117 m{sup 2}) hazardous waste surface impoundments will be discussed. 1 ref., 2 figs.
MANOVA versus alternative methods
NASA Astrophysics Data System (ADS)
Yatim, Bidin; Ismail, Suzilah
2014-12-01
Multivariate analysis of variance (MANOVA) is a powerful tool in analysing multivariate data of multi-factorial experiments. However one of the assumptions in MANOVA requires the data to be normally distributed. This study concerned with the violation of this assumption, particularly when the data are either moderately non-normal or extremely non-normal. Possible alternative methods of handling such data are (i) permutational MANOVA (PMANOVA) or (ii) analysis of distance (AoD). Both of these alternative methods were compared with MANOVA via Monte Carlo experiments using the power of tests. The experiments focussed on testing interaction effects by incorporating different data types (i.e. having multivariate normal distribution, moderately non-normal and extremely non-normal), three level of inter-variable correlations (low: 0.25, medium: 0.5 and high: 0.75), two designs (small: 3×3 and large: 7×7) and two sample sizes (2 and 5 replicates). Overall, the results revealed that irrespective of the data types and the level of inter-variable correlations MANOVA performed satisfactorily in situations having larger sample size (5 replicates). In these situations, no alternative method is necessary. However, in small design with high inter-variable correlations PMANOVA performed slightly better. In small samples (2 replicates), AoD outperformed both MANOVA and PMANOVA. This is especially true in situation having small sample (2 replicates), large design and highly correlated inter-variables.
Sandford, M.T. II; Bradley, J.N.; Handel, T.G.
1996-06-01
Data embedding is a new steganographic method for combining digital information sets. This paper describes the data embedding method and gives examples of its application using software written in the C-programming language. Sandford and Handel produced a computer program (BMPEMBED, Ver. 1.51 written for IBM PC/AT or compatible, MS/DOS Ver. 3.3 or later) that implements data embedding in an application for digital imagery. Information is embedded into, and extracted from, Truecolor or color-pallet images in Microsoft{reg_sign} bitmap (.BMP) format. Hiding data in the noise component of a host, by means of an algorithm that modifies or replaces the noise bits, is termed {open_quote}steganography.{close_quote} Data embedding differs markedly from conventional steganography, because it uses the noise component of the host to insert information with few or no modifications to the host data values or their statistical properties. Consequently, the entropy of the host data is affected little by using data embedding to add information. The data embedding method applies to host data compressed with transform, or {open_quote}lossy{close_quote} compression algorithms, as for example ones based on discrete cosine transform and wavelet functions. Analysis of the host noise generates a key required for embedding and extracting the auxiliary data from the combined data. The key is stored easily in the combined data. Images without the key cannot be processed to extract the embedded information. To provide security for the embedded data, one can remove the key from the combined data and manage it separately. The image key can be encrypted and stored in the combined data or transmitted separately as a ciphertext much smaller in size than the embedded data. The key size is typically ten to one-hundred bytes, and it is in data an analysis algorithm.
SULFIDE METHOD PLUTONIUM SEPARATION
Duffield, R.B.
1958-08-12
A process is described for the recovery of plutonium from neutron irradiated uranium solutions. Such a solution is first treated with a soluble sullide, causing precipitation of the plutoniunn and uraniunn values present, along with those impurities which form insoluble sulfides. The precipitate is then treated with a solution of carbonate ions, which will dissolve the uranium and plutonium present while the fission product sulfides remain unaffected. After separation from the residue, this solution may then be treated by any of the usual methods, such as formation of a lanthanum fluoride precipitate, to effect separation of plutoniunn from uranium.
NASA Astrophysics Data System (ADS)
Phares, Brent M.; Washer, Glenn A.; Moore, Mark; Graybeal, Benjamin A.
1999-02-01
The NDE Validation Center is a national resource for the independent and quantitative evaluation of existing and emerging NDE techniques. The resources of the NDE Validation Center are available to federal and state agencies, the academic community, and industry. The NDE Validation Center is designed to perform critical evaluations of NDE technologies and to provide a source of information and guidance to users and developers of NDE systems. This paper describes the resources available at the Center and the initial efforts to validate the visual inspection of highway bridges. Efforts to evaluate various NDE methods for the inspection of bridge hanger pins are also described.
Janney, Mark A.; Kiggans, Jr., James O.
1999-01-01
A method of drying a green particulate article includes the steps of: a. Providing a green article which includes a particulate material and a pore phase material, the pore phase material including a solvent; and b. contacting the green article with a liquid desiccant for a period of time sufficient to remove at least a portion of the solvent from the green article, the pore phase material acting as a semipermeable barrier to allow the solvent to be sorbed into the liquid desiccant, the pore phase material substantially preventing the liquid desiccant from entering the pores.
Powell, J.; Reich, M.; Danby, G.
1997-07-22
A magnetic imager includes a generator for practicing a method of applying a background magnetic field over a concealed object, with the object being effective to locally perturb the background field. The imager also includes a sensor for measuring perturbations of the background field to detect the object. In one embodiment, the background field is applied quasi-statically. And, the magnitude or rate of change of the perturbations may be measured for determining location, size, and/or condition of the object. 25 figs.
Powell, James; Reich, Morris; Danby, Gordon
1997-07-22
A magnetic imager 10 includes a generator 18 for practicing a method of applying a background magnetic field over a concealed object, with the object being effective to locally perturb the background field. The imager 10 also includes a sensor 20 for measuring perturbations of the background field to detect the object. In one embodiment, the background field is applied quasi-statically. And, the magnitude or rate of change of the perturbations may be measured for determining location, size, and/or condition of the object.
METHOD OF ISOTOPE CONCENTRATION
Taylor, T.I.; Spindel, W.
1960-02-01
A method of concentrating N/sup 15/ in a liquid is described. Gaseous nitric oxide and at least one liquid selected from the group consisting of the aqueous oxyacids and oxides of nitrogen, wherein the atomic ratio of oxygen to nitrogen is greater than unity, are brought into intimate contact to cause an enrichment of the liquid and a depletion of the gas in N/sup 15/. The liquid is, thereafter, reacted with sulfur dioxide to produce a gas contuining nitric oxide. The gas contuining nitric oxide is then continuously passed in countercurrent contact with the liquid to cause further enrichment of the liquid.
Acoustic bubble removal method
NASA Technical Reports Server (NTRS)
Trinh, E. H.; Elleman, D. D.; Wang, T. G. (Inventor)
1983-01-01
A method is described for removing bubbles from a liquid bath such as a bath of molten glass to be used for optical elements. Larger bubbles are first removed by applying acoustic energy resonant to a bath dimension to drive the larger bubbles toward a pressure well where the bubbles can coalesce and then be more easily removed. Thereafter, submillimeter bubbles are removed by applying acoustic energy of frequencies resonant to the small bubbles to oscillate them and thereby stir liquid immediately about the bubbles to facilitate their breakup and absorption into the liquid.
Method for incinerating sludges
Lalanne, J.; Nivert, J.; Tarascou, D.
1980-03-25
A method is disclosed for incinerating sludges. The process consists of the following steps: delivering a very homogeneous mixture of at least one combustible gas with a large amount of excess air at a plurality of locations in the lower part of an incineration zone; initiating the combustion of said mixture; finely pulverizing the sludge in the combustion zone; evacuating the incineration products from the incineration zone by carrying them along with the gaseous combustion products; and controlling precisely the temperature of the combustion products while they are being evacuated from the incineration zone.
Mayes, James C.
2009-05-05
A device and method provide for cooling of a system having an energy source, one or more devices that actively consume energy, and one or more devices that generate heat. The device may include one or more thermoelectric coolers ("TECs") in conductive engagement with at least one of the heat-generating devices, and an energy diverter for diverting at least a portion of the energy from the energy source that is not consumed by the active energy-consuming devices to the TECs.
Computational Methods for Crashworthiness
NASA Technical Reports Server (NTRS)
Noor, Ahmed K. (Compiler); Carden, Huey D. (Compiler)
1993-01-01
Presentations and discussions from the joint UVA/NASA Workshop on Computational Methods for Crashworthiness held at Langley Research Center on 2-3 Sep. 1992 are included. The presentations addressed activities in the area of impact dynamics. Workshop attendees represented NASA, the Army and Air Force, the Lawrence Livermore and Sandia National Laboratories, the aircraft and automotive industries, and academia. The workshop objectives were to assess the state-of-technology in the numerical simulation of crash and to provide guidelines for future research.
Method for resonant measurement
Rhodes, George W.; Migliori, Albert; Dixon, Raymond D.
1996-01-01
A method of measurement of objects to determine object flaws, Poisson's ratio (.sigma.) and shear modulus (.mu.) is shown and described. First, the frequency for expected degenerate responses is determined for one or more input frequencies and then splitting of degenerate resonant modes are observed to identify the presence of flaws in the object. Poisson's ratio and the shear modulus can be determined by identification of resonances dependent only on the shear modulus, and then using that shear modulus to find Poisson's ratio using other modes dependent on both the shear modulus and Poisson's ratio.
ZIRCONIUM PHOSPHATE ADSORPTION METHOD
Russell, E.R.; Adamson, A.S.; Schubert, J.; Boyd, G.E.
1958-11-01
A method is presented for separating plutonium values from fission product values in aqueous acidic solution. This is accomplished by flowing the solutlon containing such values through a bed of zirconium orthophosphate. Any fission products adsorbed can subsequently be eluted by washing the column with a solution of 2N HNO/sub 3/ and O.lN H/sub 3/PO/sub 4/. Plutonium values may subsequently be desorbed by contacting the column with a solution of 7N HNO/sub 3/ .
Contrast image correction method
NASA Astrophysics Data System (ADS)
Schettini, Raimondo; Gasparini, Francesca; Corchs, Silvia; Marini, Fabrizio; Capra, Alessandro; Castorina, Alfio
2010-04-01
A method for contrast enhancement is proposed. The algorithm is based on a local and image-dependent exponential correction. The technique aims to correct images that simultaneously present overexposed and underexposed regions. To prevent halo artifacts, the bilateral filter is used as the mask of the exponential correction. Depending on the characteristics of the image (piloted by histogram analysis), an automated parameter-tuning step is introduced, followed by stretching, clipping, and saturation preserving treatments. Comparisons with other contrast enhancement techniques are presented. The Mean Opinion Score (MOS) experiment on grayscale images gives the greatest preference score for our algorithm.
Huffman, Lester H.; Knoke, Gerald S.
1985-08-20
A method of hydraulically mining an underground pitched mineral vein comprising drilling a vertical borehole through the earth's lithosphere into the vein and drilling a slant borehole along the footwall of the vein to intersect the vertical borehole. Material is removed from the mineral vein by directing a high pressure water jet thereagainst. The resulting slurry of mineral fragments and water flows along the slant borehole into the lower end of the vertical borehole from where it is pumped upwardly through the vertical borehole to the surface.
Wilson, David G.; Robinett, III, Rush D.
2012-02-21
A control system design method and concomitant control system comprising representing a physical apparatus to be controlled as a Hamiltonian system, determining elements of the Hamiltonian system representation which are power generators, power dissipators, and power storage devices, analyzing stability and performance of the Hamiltonian system based on the results of the determining step and determining necessary and sufficient conditions for stability of the Hamiltonian system, creating a stable control system based on the results of the analyzing step, and employing the resulting control system to control the physical apparatus.
Moses, E.I.
1992-12-01
A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.
Method of controlling injector
Ito, S.; Minoura, M.
1989-01-17
This patent describes a method of controlling a fuel injector intermittently injecting liquid fuel to an engine comprising the steps of supplying a pulse signal to an actuator for reciprocating a valve body, varying the stroke of the valve body by a voltage signal applied to a stroke limiting member; changing the width of the pulse signal to thereby control the open time of the injector, and varying the voltage applied to the stroke limiting member to thereby control the stroke of the valve body.
Janney, M.A.; Kiggans, J.O. Jr.
1999-03-23
A method of drying a green particulate article includes the steps of: (a) Providing a green article which includes a particulate material and a pore phase material, the pore phase material including a solvent; and (b) contacting the green article with a liquid desiccant for a period of time sufficient to remove at least a portion of the solvent from the green article, the pore phase material acting as a semipermeable barrier to allow the solvent to be sorbed into the liquid desiccant, the pore phase material substantially preventing the liquid desiccant from entering the pores. 3 figs.
Alford, Kentin L.; Simmons, Kevin L.; Samuels, William D.; Zemanian, Thomas S.; Liu, Jun; Shin, Yongsoon; Fryxell, Glen E.
2009-09-15
The invention pertains to methods of forming monolayers on various surfaces. The surfaces can be selected from a wide array of materials, including, for example, aluminum dioxide, silicon dioxide, carbon and SiC. The substrates can be planar or porous. The monolayer is formed under enhanced pressure conditions. The monolayer contains functionalized molecules, and accordingly functionalizes a surface of the substrate. The properties of the functionalized substrate can enhance the substrate's applicability for numerous purposes including, for example, utilization in extracting contaminants, or incorporation into a polymeric matrix.
Alford, Kentin L.; Simmons, Kevin L.; Samuels, William D.; Zemanian, Thomas S.; Liu, Jun; Shin, Yongsoon; Fryxell, Glen E.
2009-12-08
The invention pertains to methods of forming monolayers on various surfaces. The surfaces can be selected from a wide array of materials, including, for example, aluminum dioxide, silicon dioxide, carbon and SiC. The substrates can be planar or porous. The monolayer is formed under enhanced pressure conditions. The monolayer contains functionalized molecules, and accordingly functionalizes a surface of the substrate. The properties of the functionalized substrate can enhance the substrate's applicability for numerous purposes including, for example, utilization in extracting contaminants, or incorporation into a polymeric matrix.
Revett, L. W.
1985-09-17
A well completion method comprising suspending NaCl crystals in the interval of the well bore to be perforated where the NaCl crystals are sized to bridge the perforations when the hydraulic pressure in the well bore exceeds the hydraulic pressure in the earth formation. The perforator is arranged to produce penetrations in the well bore in a radial pattern about the circumference of the well bore so as to effectively penetrate the entire circumference over a short interval. This enhances the perforation of vertical fractures in the earth formations.
Follstaedt, David M.; Moran, Michael P.
2005-03-15
A method for thinning (such as in grinding and polishing) a material surface using an instrument means for moving an article with a discontinuous surface with an abrasive material dispersed between the material surface and the discontinuous surface where the discontinuous surface of the moving article provides an efficient means for maintaining contact of the abrasive with the material surface. When used to dimple specimens for microscopy analysis, a wheel with a surface that has been modified to produce a uniform or random discontinuous surface significantly improves the speed of the dimpling process without loss of quality of finish.
Recurrent fuzzy ranking methods
NASA Astrophysics Data System (ADS)
Hajjari, Tayebeh
2012-11-01
With the increasing development of fuzzy set theory in various scientific fields and the need to compare fuzzy numbers in different areas. Therefore, Ranking of fuzzy numbers plays a very important role in linguistic decision-making, engineering, business and some other fuzzy application systems. Several strategies have been proposed for ranking of fuzzy numbers. Each of these techniques has been shown to produce non-intuitive results in certain case. In this paper, we reviewed some recent ranking methods, which will be useful for the researchers who are interested in this area.
METHOD FOR MEASURING RADIATION
Roesch, W.C.; McCall, R.C.
1961-11-21
A method for measuring an unknown integrated quantity of radiation with a condenser ionization chamber is described. The chamber is initially charged to a predetermined voltage by a voltage source. The chamber is then removed from the source and exposed to an unknown quantity of radiation for a period of time. The quantity of radiation to which the chamber was exposed is then measured by detecting the magnitude of the pulse of current necessary to recharge the chamber of its initial value through a suitable impedance. The current pulse is amplified and measured directly by a suitable pulse height analyzing system. (AEC)
Method for resonant measurement
Rhodes, G.W.; Migliori, A.; Dixon, R.D.
1996-03-05
A method of measurement of objects to determine object flaws, Poisson`s ratio ({sigma}) and shear modulus ({mu}) is shown and described. First, the frequency for expected degenerate responses is determined for one or more input frequencies and then splitting of degenerate resonant modes are observed to identify the presence of flaws in the object. Poisson`s ratio and the shear modulus can be determined by identification of resonances dependent only on the shear modulus, and then using that shear modulus to find Poisson`s ratio using other modes dependent on both the shear modulus and Poisson`s ratio. 1 fig.
Dixon, Raymond D.; Smith, Frank M.; O'Leary, Richard F.
1997-01-01
A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon.
Henager, Jr., Charles H.; Brimhall, John L.
2000-01-01
According to the method of the present invention, joining a first bi-element carbide to a second bi-element carbide, has the steps of: (a) forming a bond agent containing a metal carbide and silicon; (b) placing the bond agent between the first and second bi-element carbides to form a pre-assembly; and (c) pressing and heating the pre-assembly in a non-oxidizing atmosphere to a temperature effective to induce a displacement reaction creating a metal silicon phase bonding the first and second bi-element carbides.
Construction Material And Method
Wagh, Arun S.; Antink, Allison L.
2006-02-21
A structural material of a polystyrene base and the reaction product of the polystyrene base and a solid phosphate ceramic. The ceramic is applied as a slurry which includes one or more of a metal oxide or a metal hydroxide with a source of phosphate to produce a phosphate ceramic and a poly (acrylic acid or acrylate) or combinations or salts thereof and polystyrene or MgO applied to the polystyrene base and allowed to cure so that the dried aqueous slurry chemically bonds to the polystyrene base. A method is also disclosed of applying the slurry to the polystyrene base.
NASA Technical Reports Server (NTRS)
Zhang, Ye (Inventor); Wu, Honglu (Inventor)
2015-01-01
Systems and methods for preparing a sample for further analysis are provided. The system can include an enclosure. A membrane can be disposed within the enclosure. First and second reservoirs can be disposed within the enclosure, and at least one of the first and second reservoirs can be adapted to have a reagent disposed therein. A valve can be disposed within the enclosure and in fluid communication with the first or second reservoirs or both. The valve can also be in fluid communication with the membrane. The valve can be adapted to selectively regulate the flow of the reagent from the first reservoir, through the membrane, and into the second reservoir.
Lysimeter methods and apparatus
Clark, Don T.; Erickson, Eugene E.; Casper, William L.; Everett, David M.; Hubbell, Joel M.; Sisson, James B.
2004-12-07
A suction lysimeter for sampling subsurface liquids includes a lysimeter casing having a drive portion, a reservoir portion, and a tip portion, the tip portion including a membrane through which subsurface liquids may be sampled; a fluid conduit coupled in fluid flowing relation relative to the membrane, and which in operation facilitates the delivery of the sampled subsurface liquids from the membrane to the reservoir portion; and a plurality of tubes coupled in fluid flowing relation relative to the reservoir portion, the tubes in operation facilitating delivery of the sampled subsurface liquids from the reservoir portion for testing. A method of sampling subsurface liquids comprises using this lysimeter.
Capital investment analysis: three methods.
Gapenski, L C
1993-08-01
Three cash flow/discount rate methods can be used when conducting capital budgeting financial analyses: the net operating cash flow method, the net cash flow to investors method, and the net cash flow to equity holders method. The three methods differ in how the financing mix and the benefits of debt financing are incorporated. This article explains the three methods, demonstrates that they are essentially equivalent, and recommends which method to use under specific circumstances.
Woerner, Robert L.
1979-01-01
Method for cryoinduced uniform deposition of cryogenic materials, such as deuterium-tritium (DT) mixtures, on the inner surface of hollow spherical members, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on the inner surface of the spherical member. Heating of the cryogenic material, located within a non-isothermal compact freezing cell, is accomplished by an electrical heat pulse, whereafter the material is quickly frozen forming a uniform layer on the inner surface of the spherical member. The method is not restricted to producing a frozen layer on only the inner surface of the innermost hollow member, but where multiple concentric hollow spheres are involved, such as in multiple shell targets for lasers, electron beams, etc., layers of cryogenic material may also be formed on the inner surface of intermediate or outer spherical members, thus providing the capability of forming targets having multiple concentric layers or shells of frozen DT.
Crystallographic Lattice Boltzmann Method
NASA Astrophysics Data System (ADS)
Namburi, Manjusha; Krithivasan, Siddharth; Ansumali, Santosh
2016-06-01
Current approaches to Direct Numerical Simulation (DNS) are computationally quite expensive for most realistic scientific and engineering applications of Fluid Dynamics such as automobiles or atmospheric flows. The Lattice Boltzmann Method (LBM), with its simplified kinetic descriptions, has emerged as an important tool for simulating hydrodynamics. In a heterogeneous computing environment, it is often preferred due to its flexibility and better parallel scaling. However, direct simulation of realistic applications, without the use of turbulence models, remains a distant dream even with highly efficient methods such as LBM. In LBM, a fictitious lattice with suitable isotropy in the velocity space is considered to recover Navier-Stokes hydrodynamics in macroscopic limit. The same lattice is mapped onto a cartesian grid for spatial discretization of the kinetic equation. In this paper, we present an inverted argument of the LBM, by making spatial discretization as the central theme. We argue that the optimal spatial discretization for LBM is a Body Centered Cubic (BCC) arrangement of grid points. We illustrate an order-of-magnitude gain in efficiency for LBM and thus a significant progress towards feasibility of DNS for realistic flows.
Young, G.J.; Ohlinger, L.A.
1958-06-24
A nuclear reactor of the type which uses a liquid fuel and a method of controlling such a reactor are described. The reactor is comprised essentially of a tank for containing the liquid fuel such as a slurry of discrete particles of fissionnble material suspended in a heavy water moderator, and a control means in the form of a disc of neutron absorbirg material disposed below the top surface of the slurry and parallel thereto. The diameter of the disc is slightly smaller than the diameter of the tank and the disc is perforated to permit a flow of the slurry therethrough. The function of the disc is to divide the body of slurry into two separate portions, the lower portion being of a critical size to sustain a nuclear chain reaction and the upper portion between the top surface of the slurry and the top surface of the disc being of a non-critical size. The method of operation is to raise the disc in the reactor until the lower portion of the slurry has reached a critical size when it is desired to initiate the reaction, and to lower the disc in the reactor to reduce the size of the lower active portion the slurry to below criticality when it is desired to stop the reaction.
Nucleic acid detection methods
Smith, C.L.; Yaar, R.; Szafranski, P.; Cantor, C.R.
1998-05-19
The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3{prime}-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated. 18 figs.
Methods of Endotoxin Detection.
Su, Wenqiong; Ding, Xianting
2015-08-01
Endotoxin, present in the outer membrane of all gram-negative bacteria, can pose serious risks to human health, from irreversible shock to death. Therefore, it is essential to develop sensitive, accurate, and rapid methods for its detection. The rabbit pyrogen test is the first standard technique for endotoxin detection and, nowadays, has been replaced by the Limulus Amoebocyte Lysate test, which is the most popular detection technique for endotoxin. With in-depth understanding of endotoxin, biosensors based on endotoxin-sensing components are promising alternatives to pursue in developing low-cost, easy-operation, and fast-response endotoxin detection techniques. This article summarizes the recent advances of endotoxin detection methods with a particular emphasis on optical and electrochemical biosensors based on various sensing elements ranging from nature biomolecules to artificial materials. As the research and technological revolution continues, the highly integrated and miniaturized commercial devices for sensitively and reliably detecting endotoxin will provide a wide range of applications in people's daily life. PMID:25720597
Crystallographic Lattice Boltzmann Method.
Namburi, Manjusha; Krithivasan, Siddharth; Ansumali, Santosh
2016-01-01
Current approaches to Direct Numerical Simulation (DNS) are computationally quite expensive for most realistic scientific and engineering applications of Fluid Dynamics such as automobiles or atmospheric flows. The Lattice Boltzmann Method (LBM), with its simplified kinetic descriptions, has emerged as an important tool for simulating hydrodynamics. In a heterogeneous computing environment, it is often preferred due to its flexibility and better parallel scaling. However, direct simulation of realistic applications, without the use of turbulence models, remains a distant dream even with highly efficient methods such as LBM. In LBM, a fictitious lattice with suitable isotropy in the velocity space is considered to recover Navier-Stokes hydrodynamics in macroscopic limit. The same lattice is mapped onto a cartesian grid for spatial discretization of the kinetic equation. In this paper, we present an inverted argument of the LBM, by making spatial discretization as the central theme. We argue that the optimal spatial discretization for LBM is a Body Centered Cubic (BCC) arrangement of grid points. We illustrate an order-of-magnitude gain in efficiency for LBM and thus a significant progress towards feasibility of DNS for realistic flows. PMID:27251098
Crystallographic Lattice Boltzmann Method
Namburi, Manjusha; Krithivasan, Siddharth; Ansumali, Santosh
2016-01-01
Current approaches to Direct Numerical Simulation (DNS) are computationally quite expensive for most realistic scientific and engineering applications of Fluid Dynamics such as automobiles or atmospheric flows. The Lattice Boltzmann Method (LBM), with its simplified kinetic descriptions, has emerged as an important tool for simulating hydrodynamics. In a heterogeneous computing environment, it is often preferred due to its flexibility and better parallel scaling. However, direct simulation of realistic applications, without the use of turbulence models, remains a distant dream even with highly efficient methods such as LBM. In LBM, a fictitious lattice with suitable isotropy in the velocity space is considered to recover Navier-Stokes hydrodynamics in macroscopic limit. The same lattice is mapped onto a cartesian grid for spatial discretization of the kinetic equation. In this paper, we present an inverted argument of the LBM, by making spatial discretization as the central theme. We argue that the optimal spatial discretization for LBM is a Body Centered Cubic (BCC) arrangement of grid points. We illustrate an order-of-magnitude gain in efficiency for LBM and thus a significant progress towards feasibility of DNS for realistic flows. PMID:27251098
Nucleic Acid Detection Methods
Smith, Cassandra L.; Yaar, Ron; Szafranski, Przemyslaw; Cantor, Charles R.
1998-05-19
The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3'-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated.
Methods of Endotoxin Detection.
Su, Wenqiong; Ding, Xianting
2015-08-01
Endotoxin, present in the outer membrane of all gram-negative bacteria, can pose serious risks to human health, from irreversible shock to death. Therefore, it is essential to develop sensitive, accurate, and rapid methods for its detection. The rabbit pyrogen test is the first standard technique for endotoxin detection and, nowadays, has been replaced by the Limulus Amoebocyte Lysate test, which is the most popular detection technique for endotoxin. With in-depth understanding of endotoxin, biosensors based on endotoxin-sensing components are promising alternatives to pursue in developing low-cost, easy-operation, and fast-response endotoxin detection techniques. This article summarizes the recent advances of endotoxin detection methods with a particular emphasis on optical and electrochemical biosensors based on various sensing elements ranging from nature biomolecules to artificial materials. As the research and technological revolution continues, the highly integrated and miniaturized commercial devices for sensitively and reliably detecting endotoxin will provide a wide range of applications in people's daily life.
New Geoelectrical Prospecting Method
NASA Astrophysics Data System (ADS)
Mogilatov, V.
Some advantages and problems of a new geoelectrical prospecting method, vertical electric current soundings (VECS) are discussed. This method is based on using a new source, circular electric dipole (CED). It is unique source for the electrical prospecting, which excite only TM field. The behavior of an inductive source (loop) and a TE process are well known. Note that because of the more rapidly attenuating TM process (the exponential attenuation in a medium with the insulating base), another conventional source of a type of horizontal grounded line (combined source) behaves mostly as inductive, particulary in the late stage. The most remarkable properties of the field in TM transient process include the absence of the normal (quasi-static) magnetic field at the outer surface of a layered medium, as well as the dependence of the process on the vertical geoelectrical struc- ture (rather than on the overall longitudinal conductivity only, which is typical of the processes excited by inductive means). The source (CED-array) is installed in the following way. One of the transmitter poles is grounded in the central point. The other pole is uniformly grounded around with a radius determined by the depth of investigation desired. The author consider results of the initial field tests in the Tartar republic (oil target).
Macleish, K.G.
1958-02-11
ABS>This patent presents a method for locating a ground in a d-c circult having a number of parallel branches connected across a d-c source or generator. The complete method comprises the steps of locating the ground with reference to the mildpoint of the parallel branches by connecting a potentiometer across the terminals of the circuit and connecting the slider of the potentiometer to ground through a current indicating instrument, adjusting the slider to right or left of the mildpoint so as to cause the instrument to indicate zero, connecting the terminal of the network which is farthest from the ground as thus indicated by the potentiometer to ground through a condenser, impressing a ripple voltage on the circuit, and then measuring the ripple voltage at the midpoint of each parallel branch to find the branch in which is the lowest value of ripple voltage, and then measuring the distribution of the ripple voltage along this branch to determine the point at which the ripple voltage drops off to zero or substantially zero due to the existence of a ground. The invention has particular application where a circuit ground is present which will disappear if the normal circuit voltage is removed.
Ferreira, N.C.
1989-02-21
This patent describes an ultrasonic sound scanning method for detection of ultrasonic anomalies in a workpiece having an inspection surface and at least one formation which results in an echo-masked zone in the workpiece, the method including carrying out an inspection pass by (a) directing a beam of ultrasonic sound pulses from a probe along a beam axis through a transmission medium and impinging the beam upon the inspection surface at a selected impingement angle and thence into the workpiece, (b) receiving echo pulses thereby reflected from the workpiece, (c) displaying the echo pulses to reveal those, if any, which indicate the existence of anomalies within the workpiece, and (d) traversing the beam in a pre-selected path along the inspection surface, the improvement comprising: making one or more first inspection passes with the probe oriented so that, relative to the workpiece, the beam lies within one or more first scanning planes which are non-perpendicular to at least one of the return-reflecting formation at its point or respective points of intersection with the first plane or planes, whereby to reduce the volume of the echo-masked zone relative to that which would be generated with the probe oriented in a corresponding number or one or more scanning planes which are perpendicular to at least one return-reflecting formation.
Electrochemical catalyst recovery method
Silva, Laura J.; Bray, Lane A.
1995-01-01
A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications.
Steinberg, Meyer; Manowitz, Bernard; Waide, Charles H.
1976-01-06
Method and apparatus for producing rockbolts in the roof of a subterranean cavity in which two components of an ambient temperature curable resin system are premixed and then inserted into a bore hole. The mixture is permitted to polymerize in situ and then the hardened material is cut off at the entrance to the hole leaving a hardened portion for insertion into the next hole as a precursor. In a preferred embodiment a flexible glass roving is employed to reinforce the material in the hole and a metal tube inserted to support the roving while it is fed into the hole and also to provide venting. The roving and tube is then cut off and left in the hole.
Waveguide disturbance detection method
Korneev, Valeri A.; Nihei, Kurt T.; Myer, Larry R.
2000-01-01
A method for detection of a disturbance in a waveguide comprising transmitting a wavefield having symmetric and antisymmetric components from a horizontally and/or vertically polarized source and/or pressure source disposed symmetrically with respect to the longitudinal central axis of the waveguide at one end of the waveguide, recording the horizontal and/or vertical component or a pressure of the wavefield with a vertical array of receivers disposed at the opposite end of the waveguide, separating the wavenumber transform of the wavefield into the symmetric and antisymmetric components, integrating the symmetric and antisymmetric components over a broad frequency range, and comparing the magnitude of the symmetric components and the antisymmetric components to an expected magnitude for the symmetric components and the antisymmetric components for a waveguide of uniform thickness and properties thereby determining whether or not a disturbance is present inside the waveguide.
Kellerman, Peter
2013-12-21
The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.
Unconventional methods for clustering
NASA Astrophysics Data System (ADS)
Kotyrba, Martin
2016-06-01
Cluster analysis or clustering is a task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense or another) to each other than to those in other groups (clusters). It is the main task of exploratory data mining and a common technique for statistical data analysis used in many fields, including machine learning, pattern recognition, image analysis, information retrieval, and bioinformatics. The topic of this paper is one of the modern methods of clustering namely SOM (Self Organising Map). The paper describes the theory needed to understand the principle of clustering and descriptions of algorithm used with clustering in our experiments.
Boyd, G.E.
1958-08-26
A process is presented fer separating uranium, plutonium, and fission products ions from uranyl nitrate solutions having a pH value between 1 and 3 obtained by dissolving neutron irradiated uranium. The method consists in passing such solutions through a bed of cation exchange resin, which may be a sulfonated phenol formaidehyde type. Following the adsorption step the resin is first treated with a solution of 0.2M to 0.3M sulfuric acid to desorb the uranium. Fission product ions are then desorbed by treating the resin in phosphoric acid and 1M in nitric acid. Lastly, the plutonium may be desorbed by treating the resin with a solution approximately 0.8M in phosphoric acid and 1M in nitric acid.
Tolle, Charles R.; Clark, Denis E.; Smartt, Herschel B.; Miller, Karen S.
2009-10-06
A material-forming tool and a method for forming a material are described including a shank portion; a shoulder portion that releasably engages the shank portion; a pin that releasably engages the shoulder portion, wherein the pin defines a passageway; and a source of a material coupled in material flowing relation relative to the pin and wherein the material-forming tool is utilized in methodology that includes providing a first material; providing a second material, and placing the second material into contact with the first material; and locally plastically deforming the first material with the material-forming tool so as mix the first material and second material together to form a resulting material having characteristics different from the respective first and second materials.
Myers, J. D.
1985-06-25
A simplified, relatively inexpensive laser device, wherein the laser elements are fixed in a body exoskeleton of electrical insulating material having a low coefficient of thermal expansion. The preferred embodiment includes a shotgun type laser filter having parallel bores which receive the laser flashlamp and laser rod in fixed relation in a body chamber. The reflector surrounds the laser filter and retains the filter within the body chamber. In the preferred method of this invention, several controlled lasing pulses are generated with each illumination pulse of the flashlamp, substantially increasing the efficiency of the laser device. The number of pulses is generally controlled by increasing the voltage to the flashlamp. The rapid multiple lasing pulses generate an elongated plasma in a fluid medium, such as the vitreous fluid body of an eye which makes the laser device extemely efficient for treating glaucoma and other medical treatments.
Taylor, Charles E.; Noceti, Richard P.
1991-01-01
An improved catlayst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HC1 and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.
Electrochemical catalyst recovery method
Silva, L.J.; Bray, L.A.
1995-05-30
A method of recovering catalyst material from latent catalyst material solids includes: (a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; (b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; (c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and (d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications. 3 figs.
Geophysical Methods: an Overview
NASA Technical Reports Server (NTRS)
Becker, A.; Goldstein, N. E.; Lee, K. H.; Majer, E. L.; Morrison, H. F.; Myer, L.
1992-01-01
Geophysics is expected to have a major role in lunar resource assessment when manned systems return to the Moon. Geophysical measurements made from a lunar rover will contribute to a number of key studies: estimating regolith thickness, detection of possible large-diameter lava tubes within maria basalts, detection of possible subsurface ice in polar regions, detection of conductive minerals that formed directly from a melt (orthomagmatic sulfides of Cu, Ni, Co), and mapping lunar geology beneath the regolith. The techniques that can be used are dictated both by objectives and by our abilities to adapt current technology to lunar conditions. Instrument size, weight, power requirements, and freedom from orientation errors are factors we have considered. Among the geophysical methods we believe to be appropriate for a lunar resource assessment are magnetics, including gradiometry, time-domain magnetic induction, ground-penetrating radar, seismic reflection, and gravimetry.
Gambill, W.R.; Greene, N.D.
1960-08-30
A method is given for increasing burn-out heat fluxes under nucleate boiling conditions in heat exchanger tubes without incurring an increase in pumping power requirements. This increase is achieved by utilizing a spinning flow having a rotational velocity sufficient to produce a centrifugal acceleration of at least 10,000 g at the tube wall. At this acceleration the heat-transfer rate at burn out is nearly twice the rate which can be achieved in a similar tube utilizing axial flow at the same pumping power. At higher accelerations the improvement over axial flow is greater, and heat fluxes in excess of 50 x 10/sup 6/ Btu/hr/sq ft can be achieved.
Magnesium fluoride recovery method
Gay, Richard L.; McKenzie, Donald E.
1989-01-01
A method of obtaining magnesium fluoride substantially free from radioactive uranium from a slag containing the same and having a radioactivity level of at least about 7000 pCi/gm. The slag is ground to a particle size of about 200 microns or less. The ground slag is contacted with an acid under certain prescribed conditions to produce a liquid product and a particulate solid product. The particulate solid product is separated from the liquid and treated at least two more times with acid to produce a solid residue consisting essentially of magnesium fluoride substantially free of uranium and having a residual radioactivity level of less than about 1000 pCi/gm. In accordance with a particularly preferred embodiment of the invention a catalyst and an oxidizing agent are used during the acid treatment and preferably the acid is sulfuric acid having a strength of about 1.0 Normal.
Method for radioactivity monitoring
Umbarger, C. John; Cowder, Leo R.
1976-10-26
The disclosure relates to a method for analyzing uranium and/or thorium contents of liquid effluents preferably utilizing a sample containing counting chamber. Basically, 185.7-keV gamma rays following .sup.235 U alpha decay to .sup.231 Th which indicate .sup.235 U content and a 63-keV gamma ray doublet found in the nucleus of .sup.234 Pa, a granddaughter of .sup.238 U, are monitored and the ratio thereof taken to derive uranium content and isotopic enrichment .sup.235 U/.sup.235 U + .sup.238 U) in the liquid effluent. Thorium content is determined by monitoring the intensity of 238-keV gamma rays from the nucleus of .sup.212 Bi in the decay chain of .sup.232 Th.
Microencapsulation system and method
NASA Technical Reports Server (NTRS)
Morrison, Dennis R. (Inventor)
2009-01-01
A microencapsulation apparatus is provided which is configured to form co-axial multi-lamellar microcapsules from materials discharged from first and second microsphere dispensers of the apparatus. A method of fabricating and processing microcapsules is also provided which includes forming distinct droplets comprising one or more materials and introducing the droplets directly into a solution bath to form a membrane around the droplets such that a plurality of microcapsules are formed. A microencapsulation system is provided which includes a microcapsule production unit, a fluidized passage for washing and harvesting microcapsules dispensed from the microcapsule production unit and a flow sensor for sizing and counting the microcapsules. In some embodiments, the microencapsulation system may further include a controller configured to simultaneously operate the microcapsule production unit, fluidized passage and flow sensor to process the microcapsules in a continuous manner.
Microencapsulation system and method
NASA Technical Reports Server (NTRS)
Morrison, Dennis R. (Inventor)
2006-01-01
A microencapsulation apparatus is provided which is configured to form co-axial multi-lamellar microcapsules from materials discharged from first and second microsphere dispensers of the apparatus. A method of fabricating and processing microcapsules is also provided which includes forming distinct droplets comprising one or more materials and introducing the droplets directly into a solution bath to form a membrane around the droplets such that a plurality of microcapsules are formed. A microencapsulation system is provided which includes a microcapsule production unit, a fluidized passage for washing and harvesting microcapsules dispensed from the microcapsule production unit and a flow sensor for sizing and counting the microcapsules. In some embodiments, the microencapsulation system may further include a controller configured to simultaneously operate the microcapsule production unit, fluidized passage and flow sensor to process the microcapsules in a continuous manner.
Predictive spark timing method
Tang, D.L.; Chang, M.F.; Sultan, M.C.
1990-01-09
This patent describes a method of determining spark time in a spark timing system of an internal combustion engine having a plurality of cylinders and a spark period for each cylinder in which a spark occurs. It comprises: generating at least one crankshaft position reference pulse for each spark firing event, the reference pulse nearest the next spark being set to occur within a same cylinder event as the next spark; measuring at least two reference periods between recent reference pulses; calculating the spark timing synchronously with crankshaft position by performing the calculation upon receipt of the reference pulse nearest the next spark; predicting the engine speed for the next spark period from at least two reference periods including the most recent reference period; and based on the predicted speed, calculating a spark time measured from the the reference pulse nearest the next spark.
Methods for studying oogenesis
Hudson, Andrew M.; Cooley, Lynn
2014-01-01
Drosophila oogenesis is an excellent system for the study of developmental cell biology. Active areas of research include stem cell maintenance, gamete development, pattern formation, cytoskeletal regulation, intercellular communication, intercellular transport, cell polarity, cell migration, cell death, morphogenesis, cell cycle control, and many more. The large size and relatively simple organization of egg chambers make them ideally suited for microscopy of both living and fixed whole mount tissue. A wide range of tools is available for oogenesis research. Newly available shRNA transgenic lines provide an alternative to classic loss-of-function F2 screens and clonal screens. Gene expression can be specifically controlled in either germline or somatic cells using the Gal4/UAS system. Protein trap lines provide fluorescent tags of proteins expressed at endogenous levels for live imaging and screening backgrounds. This review provides information on many available reagents and key methods for research in oogenesis. PMID:24440745
Imhoff, D.H.; Harker, W.H.
1964-02-01
A method for producing neutrons is described in which there is employed a confinement zone defined between longitudinally spaced localized gradient regions of an elongated magnetic field. Changed particles and neutralizing electrons, more specifically deuterons and tritons and neutralizng electrons, are injected into the confinement field from ion sources located outside the field. The rotational energy of the parrticles is increased at the gradients by imposing an oscillating transverse electrical field thereacross. The imposition of such oscillating transverse electrical fields improves the reflection capability of such gradient fielda so that the reactive particles are retained more effectively within the zone. With the attainment of appropriate densities of plasma particles and provided that such particles are at a sufficiently high temperature, neutron-producing reactions ensue and large quantities of neutrons emerge from the containment zone. (AEC)
Bone, W.H.; Schmidt, W.W.
1958-11-01
A method is presented for forming refractory liners in cylindrical reaction vessels used for the reductlon of uranium tetrafluoride to metallic uranium. A preliminary form, having positioning lugs attached thereto, is inserted into the reaction vessel and the refractory powder, usually CaO, is put in the annular space between the form and the inner wall of the reaction vessel. A jolting table is used to compact this charge of liner material ln place, and after thls has been done, the preliminary form is removed and the flnal form or plug is lnserted without disturbing the partially completed lining. The remainder of the lining charge is then introduced and compacted by jolting, after which the form is removed.
Taylor, C.E.; Noceti, R.P.
1990-12-31
An improved catalyst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HCl and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride. 8 figs., 3 tabs.
Coppa, Nicholas V.; Stewart, Paul; Renzi, Ernesto
1999-01-01
The present invention provides methods and apparatus for freeze drying in which a solution, which can be a radioactive salt dissolved within an acid, is frozen into a solid on vertical plates provided within a freeze drying chamber. The solid is sublimated into vapor and condensed in a cold condenser positioned above the freeze drying chamber and connected thereto by a conduit. The vertical positioning of the cold condenser relative to the freeze dryer helps to help prevent substances such as radioactive materials separated from the solution from contaminating the cold condenser. Additionally, the system can be charged with an inert gas to produce a down rush of gas into the freeze drying chamber to also help prevent such substances from contaminating the cold condenser.
METHOD FOR PREPARING NORMORPHINE
Rapoport, H.; Look, M.
1959-06-01
An improved method is presented for producing normorphine from morphine. Morphine as the starting material is acetylated by treatment with acetylating agents to produce di-acetyl morphine (heroin). The acetylated compound is reacted with cyanating agents to produce di-acetyl-cyanonormorphine (cyanonorheroin). The di-acetyl-cyanonormorphine compound is then treated in accordance with the improved hydrolysis reactions of the present invention in which concentrated hydrochloric acid is employed for a limited time period to hydrolyze the acetyl group therefrom forming cyanonormorphine. Subsequently, the reaction mixture is diluted and hydrolysis of the cyano groups from the cyanonormorphine is effected with a longer contact time with dilute hydrochloric acid thereby producing normorphine. A high over-all conversion and production of a high purity product which may be radioactlvely labeled, if desired, is obtained by operation of the process.
Method for stabilizing hydroisomerates
Cody, I.A.; Eadie, D.T.; MacDonald, J.M.; Hamner, G.P.
1992-10-27
This patent describes a method for improving the daylight stability of a lube oil base stock or blending stock produced by the isomerization of slack wax containing from 0% to 25% oil coming from the dewaxing of conventional petroleum crude oils. It comprises: hydrorefining the total liquid product produced in the petroleum slack wax isomerization unit the hydrorefining being practiced under mild conditions the conditions including a temperature of 170[degrees] to 270[degrees]C, a flow velocity of 0.25 to 10 v/v/hr., a pressure of 300 to 1500 psi h[sub 2], and a hydrogen gas rate of 500 to 10,000 SCF H[sub 2]/bbl using a Group VIII metal on halogenated refractory metal oxide catalyst.
Acoustophoresis method and apparatus
NASA Technical Reports Server (NTRS)
Heyman, Joseph S. (Inventor)
1992-01-01
A method and apparatus are provided for acoustophoresis, i.e., the separation of species via acoustic waves. An ultrasonic transducer applies an acoustic wave to one end of a sample container containing at least two species having different acoustic absorptions. The wave has a frequency tuned to or harmonized with the point of resonance of the species to be separated. This wave caused the species to be driven to an opposite end of the sample container for removal. A second ultrasonic transducer may be provided to apply a second, oppositely directed acoustic wave to prevent undesired streaming. In addition, a radio frequency tuned to the mechanical resonance and coupled with a magnetic field can serve to identify a species in a medium comprising species with similar absorption coefficients, whereby an acoustic wave having a frequency corresponding to this gyrational rate can then be applied to sweep the identified species to one end of the container for removal.
Acoustophoresis separation method
NASA Technical Reports Server (NTRS)
Heyman, Joseph S. (Inventor)
1993-01-01
A method and apparatus are provided for acoustophoresis, i.e., the separation of species via acoustic waves. An ultrasonic transducer applies an acoustic wave to one end of a sample container containing at least two species having different acoustic absorptions. The wave has a frequency tuned to or harmonized with the point of resonance of the species to be separated. This wave causes the species to be driven to an opposite end of the sample container for removal. A second ultrasonic transducer may be provided to apply a second, oppositely directed acoustic wave to prevent undesired streaming. In addition, a radio frequency tuned to the mechanical resonance and coupled with a magnetic field can serve to identify a species in a medium comprising species with similar absorption coefficients, whereby an acoustic wave having a frequency corresponding to this gyrational rate can then be applied to sweep the identified species to one end of the container for removal.
Watkins, D.R.
1986-02-25
A method is described for injecting steam into a subterranean reservoir via a well penetrating the reservoir, comprising adding to steam generator feedwater used to generate the steam or adding to the steam, or adding to both the feedwater and the steam. The mixture consists of: (a) a compound selected from the group consisting of ammonium salts of inorganic acids, ammonium salts of carboxylic acids, quaternary ammonium halides, amine or substituted amine hydrochlorides, and mixtures thereof; and (b) a compound selected from the group consisting of ammonia, salts which decompose to form acid neutralizers or buffers having alkaline pH values, amides of carbamic acid or thiocarbamic acid and derivatives of such amides, tertiary carboxylic acid amides and their substituted and alkylated derivatives, and mixtures thereof.
Method for controlling brazing
Hosking, F. Michael; Hall, Aaron C.; Givler, Richard C.; Walker, Charles A.
2006-08-01
A method for making a braze joint across a discontinuity in a work piece using alternating current. A filler metal is pre-placed at a location sufficiently close to the discontinuity such that, when an alternating current is applied across a work piece to heat the work piece and melt the filler metal, the filler metal is drawn into the discontinuity. The alternating current is maintained for a set residence time, generally less than 10 seconds and more particularly less than 3 seconds. The alternating current is then altered, generally by reducing the current and/or voltage such that the filler metal can solidify to form a braze joint of desired quality and thickness.
Tensiometer methods and apparatus
Grover, Blair K.; Hubbell, Joel M.; Sisson, James B.; Casper, William L.
2004-08-10
A method for collecting data regarding a matric potential of a media includes providing a tensiometer having a stainless steel tensiometer casing, the stainless steel tensiometer casing comprising a tip portion which includes a wetted porous stainless steel membrane through which a matric potential of a media is sensed; driving the tensiometer into the media using an insertion tube comprising a plurality of probe casing which are selectively coupled to form the insertion tube as the tensiometer is progressively driven deeper into the media, wherein the wetted porous stainless steel membrane is in contact with the media; and sensing the matric potential the media exerts on the wetted porous stainless steel membrane by a pressure sensor in fluid hydraulic connection with the porous stainless steel membrane. A tensiometer includes a stainless steel casing.
Standard environmental test methods
Schafer, D R
1983-12-01
This guide to uniformity in testing is intended primarily as an aid to persons responsible for designing, developing, and performing environmental tests. It will also be of use to those concerned with production, evaluation, and quality control and assurance. Checklists for preparing the environmental testing portion of product specifications are included, as are copies of Process Standards covering the instrumentation, equipment, and methods for use in environmental testing of Sandia National Laboratories components. Techniques and equipment are constantly improving. This version of SC-4452 reflects current state-of-the-art and practice in environmental testing. Previously existing sections of the document have ben updated and new ones have been added, e.g., Transient Testing on Vibration Machines.
Voges, B.
1984-06-05
A method of and a device for blast heating is described, employing separate indirect heat exchangers for combustion air and fuel gas fed to a regenerator and flue gases discharged from the regenerator. The indirect heat exchangers share heat-transfer liquid recirculating in a circuit in which an auxiliary heat exchanger is connected. In the latter exchanger, the temperature of transfer liquid is increased by combustion of partial streams of combustion air and fuel gas branched off downstream of the indirect heat exchangers. The temperature is increased to such a value which preheats the fuel gas to a temperature at which a substitution of fuel gas of a low calorific value, such as waste gas from a blast furnace, for fuel gas of high calorific value, is made possible.
McGuire, Raymond R.; Coon, Clifford L.; Harrar, Jackson E.; Pearson, Richard K.
1984-01-01
A method and apparatus for electrochemically synthesizing N.sub.2 O.sub.5 cludes oxidizing a solution of N.sub.2 O.sub.4 /HNO.sub.3 at an anode, while maintaining a controlled potential between the N.sub.2 O.sub.4 /HNO.sub.3 solution and the anode. A potential of about 1.35 to 2.0 V vs. SCE is preferred, while a potential of about 1.80 V vs. SCE is most preferred. Thereafter, the N.sub.2 O.sub.5 is reacted with either 1.5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane (DADN) or 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane (TAT) to form cyclotetramethylenetetraamine (HMX).
METHOD OF SEPARATING PLUTONIUM
Brown, H.S.; Hill, O.F.
1958-02-01
Plutonium hexafluoride is a satisfactory fluorinating agent and may be reacted with various materials capable of forming fluorides, such as copper, iron, zinc, etc., with consequent formation of the metal fluoride and reduction of the plutonium to the form of a lower fluoride. In accordance with the present invention, it has been found that the reactivity of plutonium hexafluoride with other fluoridizable materials is so great that the process may be used as a method of separating plutonium from mixures containing plutonium hexafluoride and other vaporized fluorides even though the plutonium is present in but minute quantities. This process may be carried out by treating a mixture of fluoride vapors comprising plutonium hexafluoride and fluoride of uranium to selectively reduce the plutonium hexafluoride and convert it to a less volatile fluoride, and then recovering said less volatile fluoride from the vapor by condensation.
Dixon, R.D.; Smith, F.M.; O`Leary, R.F.
1997-04-01
A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs.
Fisher, R.W.
1957-12-10
A method is described for recovering thorium from impurities found in a slag containing thorium and said impurities, comprising leaching a composition containing thorium with water, removing the water solution, treating the residue with hydrochloric acid, separating the solution from the insoluble residue, adjusting its acidity to 1 to 3 normal, adding oxalic acid, and thereafter separating the precipitated thorium oxalate digesting the residue from the hydrochloric acid treatment with a strong solution of sodium hydroxide at an elevated temperature, removing said solution and treating the insoluble residue with hydrochloric acid, separating the solution from the insoluble residue, adjusting the acidity of this solution to 1 to 3 normal, adding nitric acid to oxidize the iron present, adding oxalic acid and thereafter separating the thorium oxalate thus precipitated.
Radiofrequency attenuator and method
Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.; Agrawal, Anoop; Hall, Simon B.
2009-01-20
Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.
Radiofrequency attenuator and method
Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.; Agrawal, Anoop; Hall, Simon B.
2009-11-10
Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3 C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.
Kennedy, J.W.; Segre, E.G.
1958-08-26
A method is presented for obtaining a compound of uranium in an extremely pure state and in such a condition that it can be used in determinations of the isotopic composition of uranium. Uranium deposited in calutron receivers is removed therefrom by washing with cold nitric acid and the resulting solution, coataining uranium and trace amounts of various impurities, such as Fe, Ag, Zn, Pb, and Ni, is then subjected to various analytical manipulations to obtain an impurity-free uranium containing solution. This solution is then evaporated on a platinum disk and the residue is ignited converting it to U2/sub 3//sub 8/. The platinum disk having such a thin film of pure U/sub 2/O/sub 8/ is suitable for use with isotopic determination techaiques.
Ponzetto, Federico; Giraud, Sylvain; Leuenberger, Nicolas; Boccard, Julien; Nicoli, Raul; Baume, Norbert; Rudaz, Serge; Saugy, Martial
2016-01-01
Over the past few years, the World Anti-Doping Agency (WADA) has focused its efforts on detecting not only small prohibited molecules, but also larger endogenous molecules such as hormones, in the view of implementing an endocrinological module in the Athlete Biological Passport (ABP). In this chapter, the detection of two major types of hormones used for doping, growth hormone (GH) and endogenous anabolic androgenic steroids (EAASs), will be discussed: a brief historical background followed by a description of state-of-the-art methods applied by accredited anti-doping laboratories will be provided and then current research trends outlined. In addition, microRNAs (miRNAs) will also be presented as a new class of biomarkers for doping detection. PMID:27348309
DeNardo, Sally J.; Burke, Patricia A.; DeNardo, Gerald L.; Goodman, Simon; Matzku, legal representative, Kerstin; Matzku, Siegfried
2006-04-18
A method of treating tumors, such as prostate tumors, breast tumors, non-Hodgkin's lymphoma, and the like, includes the sequential steps of administering to the patient at least one dose of an antiangiogenic cyclo-arginine-glycine-aspartic acid-containing pentapeptide (cRGD pentapeptide); administering to the patient an anti-tumor effective amount of a radioimmunotherapeutic agent (RIT); and then administering to the patient at least one additional dose of cRGD pentapeptide. The cRGD pentapeptide is preferably cyclo-(Arg-Gly-Asp-D-Phe-[N-Me]-Val), and the RIT is preferably a radionuclide-labeled chelating agent-ligand complex in which chelating agent is chemically bonded to a tumor-targeting molecule, such as a monoclonal antibody.
Method for maskless lithography
Sweatt, William C.; Stulen, Richard H.
2000-01-01
The present invention provides a method for maskless lithography. A plurality of individually addressable and rotatable micromirrors together comprise a two-dimensional array of micromirrors. Each micromirror in the two-dimensional array can be envisioned as an individually addressable element in the picture that comprises the circuit pattern desired. As each micromirror is addressed it rotates so as to reflect light from a light source onto a portion of the photoresist coated wafer thereby forming a pixel within the circuit pattern. By electronically addressing a two-dimensional array of these micromirrors in the proper sequence a circuit pattern that is comprised of these individual pixels can be constructed on a microchip. The reflecting surface of the micromirror is configured in such a way as to overcome coherence and diffraction effects in order to produce circuit elements having straight sides.
Olson, Eric J.
2013-06-11
An apparatus, program product, and method that run an algorithm on a hardware based processor, generate a hardware error as a result of running the algorithm, generate an algorithm output for the algorithm, compare the algorithm output to another output for the algorithm, and detect the hardware error from the comparison. The algorithm is designed to cause the hardware based processor to heat to a degree that increases the likelihood of hardware errors to manifest, and the hardware error is observable in the algorithm output. As such, electronic components may be sufficiently heated and/or sufficiently stressed to create better conditions for generating hardware errors, and the output of the algorithm may be compared at the end of the run to detect a hardware error that occurred anywhere during the run that may otherwise not be detected by traditional methodologies (e.g., due to cooling, insufficient heat and/or stress, etc.).
Saller, deceased, Henry A.; Hodge, Edwin S.; Paprocki, Stanley J.; Dayton, Russell W.
1987-12-01
1. A method of making a fuel-containing structure for nuclear reactors, comprising providing an assembly comprising a plurality of fuel units; each fuel unit consisting of a core plate containing thermal-neutron-fissionable material, sheets of cladding metal on its bottom and top surfaces, said cladding sheets being of greater width and length than said core plates whereby recesses are formed at the ends and sides of said core plate, and end pieces and first side pieces of cladding metal of the same thickness as the core plate positioned in said recesses, the assembly further comprising a plurality of second side pieces of cladding metal engaging the cladding sheets so as to space the fuel units from one another, and a plurality of filler plates of an acid-dissolvable nonresilient material whose melting point is above 2000.degree. F., each filler plate being arranged between a pair of said second side pieces and the cladding plates of two adjacent fuel units, the filler plates having the same thickness as the second side pieces; the method further comprising enclosing the entire assembly in an envelope; evacuating the interior of the entire assembly through said envelope; applying inert gas under a pressure of about 10,000 psi to the outside of said envelope while at the same time heating the assembly to a temperature above the flow point of the cladding metal but below the melting point of any material of the assembly, whereby the envelope is pressed against the assembly and integral bonds are formed between plates, sheets, first side pieces, and end pieces and between the sheets and the second side pieces; slowly cooling the assembly to room temperature; removing the envelope; and dissolving the filler plates without attacking the cladding metal.
Characterization Methods of Encapsulates
NASA Astrophysics Data System (ADS)
Zhang, Zhibing; Law, Daniel; Lian, Guoping
, reliable methods which can be used to characterize these properties of encapsulates are vital. In this chapter, the state-of-art of these methods, their principles and applications, and release mechanisms are described as follows.
Theurich, Gordon R.
1976-01-01
1. In a method of separating isotopes in a high speed gas centrifuge wherein a vertically oriented cylindrical rotor bowl is adapted to rotate about its axis within an evacuated chamber, and wherein an annular molecular pump having an intake end and a discharge end encircles the uppermost portion of said rotor bowl, said molecular pump being attached along its periphery in a leak-tight manner to said evacuated chamber, and wherein end cap closure means are affixed to the upper end of said rotor bowl, and a process gas withdrawal and insertion system enters said bowl through said end cap closure means, said evacuated chamber, molecular pump and end cap defining an upper zone at the discharge end of said molecular pump, said evacuated chamber, molecular pump and rotor bowl defining a lower annular zone at the intake end of said molecular pump, a method for removing gases from said upper and lower zones during centrifuge operation with a minimum loss of process gas from said rotor bowl, comprising, in combination: continuously measuring the pressure in said upper zone, pumping gas from said lower zone from the time the pressure in said upper zone equals a first preselected value until the pressure in said upper zone is equal to a second preselected value, said first preselected value being greater than said second preselected value, and continuously pumping gas from said upper zone from the time the pressure in said upper zone equals a third preselected value until the pressure in said upper zone is equal to a fourth preselected value, said third preselected value being greater than said first, second and fourth preselected values.
[Chemical methods of abortion].
Schmidt-Matthiesen, H
1979-07-20
Medicaments are used to prepare for instrument abortions in the 1st trimester and as inducers of abortion in the 2nd trimester. The effects, side effects, and dangers depend on the substances used and the route of application, which can be vaginal, cervical, injection, instillation, extraamniotic, intraamniotic, intravenous, or intramuscular. In the past, intraamniotic instillation of a 20% salt solution was the most common 2nd trimester method in Japan, the US, and Eastern Europe, giving a success rate of 90%. Serious side effects prompted substitution of extraamniotic instillation, which rarely produces serious side effects. Instillation of a 60% urea solution into the amniotic fluid in combination with oxytocin or prostaglandin produces an abortion in 13-21 hours, with a failure rate of 3% and a frequency of cervical laceration of under 1%. Extraamniotic use of a .1% solution of rivanol yields a success rate of about 85%, with a relatively long average time to explusion of 24-41 hours. In case of failure the procedure can be repeated. The advantage of the Rivanol method is the rarity of infectious complications. Alcohol is not used as a human abortifacient because it produces necrosis in the decidua and placenta. Prostaglandins are used in most 2nd trimester abortions. Research is underway to identify derivatives that will have an extended uterine impact without serious side effects. Different routes of administration have different effectiveness rates and dangers. All prostaglandins cause side effects including pain during uterine contractions, gastro-intestinal reactions, nausea, vomiting, fever, and headaches. Specific preparations are associated with other effects, some of them life-threatening. Emergency treatment should be available when these substances are used. Adjuvant measures may be employed before adminstration of an abortifacient agent to soften the cervix, or after administration to hasten the procedure. The choice of procedure depends upon the
Linear and nonlinear dynamic analysis of redundant load path bearingless rotor systems
NASA Technical Reports Server (NTRS)
Murthy, V. R.; Shultz, Louis A.
1994-01-01
The goal of this research is to develop the transfer matrix method to treat nonlinear autonomous boundary value problems with multiple branches. The application is the complete nonlinear aeroelastic analysis of multiple-branched rotor blades. Once the development is complete, it can be incorporated into the existing transfer matrix analyses. There are several difficulties to be overcome in reaching this objective. The conventional transfer matrix method is limited in that it is applicable only to linear branch chain-like structures, but consideration of multiple branch modeling is important for bearingless rotors. Also, hingeless and bearingless rotor blade dynamic characteristics (particularly their aeroelasticity problems) are inherently nonlinear. The nonlinear equations of motion and the multiple-branched boundary value problem are treated together using a direct transfer matrix method. First, the formulation is applied to a nonlinear single-branch blade to validate the nonlinear portion of the formulation. The nonlinear system of equations is iteratively solved using a form of Newton-Raphson iteration scheme developed for differential equations of continuous systems. The formulation is then applied to determine the nonlinear steady state trim and aeroelastic stability of a rotor blade in hover with two branches at the root. A comprehensive computer program is developed and is used to obtain numerical results for the (1) free vibration, (2) nonlinearly deformed steady state, (3) free vibration about the nonlinearly deformed steady state, and (4) aeroelastic stability tasks. The numerical results obtained by the present method agree with results from other methods.
Methods and Technologies Branch (MTB)
The Methods and Technologies Branch focuses on methods to address epidemiologic data collection, study design and analysis, and to modify technological approaches to better understand cancer susceptibility.
Hathaway, Thomas J.
1979-01-01
This invention provides a housing containing a rotatable coal bucket that is sealed at its ends in the housing with a reciprocal plunger that is sealed in the bucket at one end and has an opposite cone-shaped end that wedges up against a closed end of the bucket, and a method for feeding dry, variable size coal from an ambient atmosphere at low pressure into a high temperature, high pressure reactor between the seals for producing fuel gas substantially without losing any high pressure gas from the reactor or excessively wearing the seals. To this end, the piston biases the plunger back and forth for loading and unloading the bucket with coal along an axis that is separated from the seals, the bucket is rotated to unload the coal into the reactor so as to fill the bucket with trapped high pressure gas from the reactor while preventing the gas from escaping therefrom, and then the cone-shaped plunger end is wedged into mating engagement with the closed end of the bucket to displace this high pressure bucket gas by expelling it back into the reactor whereby the bucket can be re-rotated for filling it with coal again substantially without losing any of the high pressure gas or excessively wearing the seals.
Methods of channeling simulation
Barrett, J.H.
1989-06-01
Many computer simulation programs have been used to interpret experiments almost since the first channeling measurements were made. Certain aspects of these programs are important in how accurately they simulate ions in crystals; among these are the manner in which the structure of the crystal is incorporated, how any quantity of interest is computed, what ion-atom potential is used, how deflections are computed from the potential, incorporation of thermal vibrations of the lattice atoms, correlations of thermal vibrations, and form of stopping power. Other aspects of the programs are included to improve the speed; among these are table lookup, importance sampling, and the multiparameter method. It is desirable for programs to facilitate incorporation of special features of interest in special situations; examples are relaxations and enhanced vibrations of surface atoms, easy substitution of an alternate potential for comparison, change of row directions from layer to layer in strained-layer lattices, and different vibration amplitudes for substitutional solute or impurity atoms. Ways of implementing all of these aspects and features and the consequences of them will be discussed. 30 refs., 3 figs.
NASA Technical Reports Server (NTRS)
Arndt, G. Dickey (Inventor); Ngo, Phong H. (Inventor); Carl, James R. (Inventor); Byerly, Kent A. (Inventor); Dusl, John (Inventor)
2003-01-01
Transceiver and methods are included that are especially suitable for detecting metallic materials, such as metallic mines, within an environment. The transceiver includes a digital waveform generator used to transmit a signal into the environment and a receiver that produces a digital received signal. A tracking module preferably compares an in-phase and quadrature transmitted signal with an in-phase and quadrature received signal to produce a spectral transfer function of the magnetic transceiver over a selected range of frequencies. The transceiver initially preferably creates a reference transfer function which is then stored in a memory. Subsequently measured transfer functions will vary depending on the presence of metal in the environment which was not in the environment when the reference transfer function was determined. The system may be utilized in the presence of other antennas, metal, and electronics which may comprise a plastic mine detector for detecting plastic mines. Despite the additional antennas and other metallic materials that may be in the environment due to the plastic mine detector, the magnetic transceiver remains highly sensitive to metallic material which may be located in various portions of the environment and which may be detected by sweeping the detector over ground that may contain metals or mines.
Desulfurization apparatus and method
Rong, Charles; Jiang, Rongzhong; Chu, Deryn
2013-06-18
A method and system for desulfurization comprising first and second metal oxides; a walled enclosure having an inlet and an exhaust for the passage of gas to be treated; the first and second metal oxide being combinable with hydrogen sulfide to produce a reaction comprising a sulfide and water; the first metal oxide forming a first layer and the second metal oxide forming a second layer within the walled surroundings; the first and second layers being positioned so the first layer removes the bulk amount of the hydrogen sulfide from the treated gas prior to passage through the second layer, and the second layer removes substantially all of the remaining hydrogen sulfide from the treated gas; the first metal oxide producing a stoichiometrical capacity in excess of 500 mg sulfur/gram; the second metal oxide reacts with the hydrogen sulfide more favorably but has a stoichometrical capacity which is less than the first reactant; whereby the optimal amount by weight of the first and second metal oxides is achieved by utilizing two to three units by weight of the first metal oxide for every unit of the second metal oxide.
Method for biological purification
Lucido, John A.; Keenan, Daniel; Premuzic, Eugene T.; Lin, Mow S.; Shelenkova, Ludmila
2001-03-27
An apparatus is disclosed for containing a microorganism culture in an active exponential growth and delivering a supply of microorganisms to an environment containing wastes for bio-augmenting the biodegradation of the wastes. The apparatus comprises a bioreactor and an operably connected controller. The bioreactor has a bioreactor chamber for containing a supply of microorganisms, a second chamber for containing a supply of water and inorganic nutrients, and a third chamber for containing a supply of organic nutrients. The bioreactor is operably connected to the controller in which a first pump is operably connected in fluid communication between the bioreactor chamber and the second chamber and third chamber, and a second pump is operably connected in fluid communication between the bioreactor chamber and the environment containing wastes to be biodegraded. The controller further includes a timer and regulator operably connected to the first and second pumps to effectively maintain the microorganisms in exponential growth in the bioreactor chamber and to deliver microorganisms to an environment to be treated. Also, disclosed is a method for bio-augmenting the biodegradation of wastes.
Chromatographic methods of fractionation.
Friesen, A D
1987-01-01
Chromatography's functional versatility, separation efficiency, gentle non-denaturing separating process and ease of automation and scale-up make it attractive for industrial scale protein purification. The Winnipeg Rh Institute's new Plasma Fractionation facility is an example of the use of chromatography for the large scale purification of plasma protein fractions. The fractionation facility has a capacity to process 800 litres of plasma per batch into blood clotting factor VIII and IX, albumin and intravenous immune serum globulin (i.v. ISG). Albumin and i.v. ISG are purified using ion exchange columns of DEAE-Sepharose (230 litre size), DEAE-Biogel (150 litre size) and CM-Sepharose (150 litre size). The chromatographic process is automated using a Modicon 584 Programmable Logic Controller to regulate valves, pumps and sensors which control plasma flow during fractionation. The stainless steel tanks and piping are automatically cleaned-in-place. The high degree of automation and cleaning provides efficient operation and sanitary processing. Chromatographic methods (DEAE-Sepharose and metal chelation) are also being used at the pilot scale to purify the human blood products superoxide dismutase and hemoglobin from outdated red blood cells. Characterization of the protein fractions produced by chromatography has shown them to be of equal or higher quality than fractions produced by other techniques.
Jones, E.M. Jr.
1985-03-12
A method is described for producing tertiary ethers from C[sub 4] or C[sub 5] streams containing isobutene and isoamylene respectively in a process wherein a acidic cation exchange resin is used as the catalyst and as a distillation structure in a distillation reactor column, wherein the improvement is the operation of the catalytic distillation in two zones at different pressures, the first zone containing the catalyst packing and operated a higher pressure in the range of 100 to 200 psig in the case of C[sub 4] and 15 to 100 psig in the case of C[sub 5] which favors the etherification reaction and the second zone being a distillation operated at a lower pressure in the range of 0 to 100 psig in the case of C[sub 4] and 0 to 15 psig in the case of C[sub 5] wherein a first overhead from the first zone is fractionated to remove a portion of the unreacted alcohol from the first overhead and to return a condensed portion containing said alcohol to the first zone and to produce a second overhead having less alcohol than said first overhead. 3 figs.
Jones, Jr., Edward M.
1985-01-01
A method for producing tertiary ethers from C.sub.4 or C.sub.5 streams containing isobutene and isoamylene respectively in a process wherein a acidic cation exchange resin is used as the catalyst and as a distillation structure in a distillation reactor column, wherein the improvement is the operation of the catalytic distillation in two zones at different pressures, the first zone containing the catalyst packing and operated a higher pressure in the range of 100 to 200 psig in the case of C.sub.4 's and 15 to 100 psig in the case of C.sub.5 's which favors the etherification reaction and the second zone being a distillation operated at a lower pressure in the range of 0 to 100 psig in the case of C.sub.4 's and 0 to 15 psig in the case of C.sub.5 's wherein a first overhead from the first zone is fractionated to remove a portion of the unreacted alcohol from the first overhead and to return a condensed portion containing said alcohol to the first zone and to produce a second overhead having less alcohol than said first overhead.
Bray, Lane Allan; DesChane, Jaquetta R.
1998-01-01
A method for separating .sup.213 Bi from a solution of radionuclides wherein the solution contains a concentration of the chloride ions and hydrogen ions adjusted to allow the formation of a chloride complex. The solution is then brought into contact with an anion exchange resin, whereupon .sup.213 Bi is absorbed from the solution and adhered onto the anion exchange resin in the chloride complex. Other non-absorbing radionuclides such as .sup.225 Ra, .sup.225 Ac, and .sup.221 Fr, along with HCl are removed from the anion exchange resin with a scrub solution. The .sup.213 Bi is removed from the anion exchange resin by washing the anion exchange resin with a stripping solution free of chloride ions and with a reduced hydrogen ion concentration which breaks the chloride anionic complex, releasing the .sup.213 Bi as a cation. In a preferred embodiment of the present invention, the anion exchange resin is provided as a thin membrane, allowing for extremely rapid adherence and stripping of the .sup.213 Bi. A preferred stripping solution for purification of .sup.213 Bi for use in medical applications includes sodium acetate, pH 5.5. A protein conjugated with bifunctional chelating agents in vivo with the NaOAc, to receive the .sup.213 Bi as it is being released from the anion exchange resin.
Rogers, J.R. Jr.
1992-09-15
This patent describes the method for operating a well installation having a control valve regulating the flow of fluid hydrocarbon from a well tubing string to a sales line which is selectively actuated between an on-state and an off-state, and wherein a plunger is located within the the tubing string of the well for movement between a lower region and a wellhead sensing position, it comprises: assigning first values; assigning second values; assigning a predetermined value for the time interval of the on-state; assigning a predetermined value for time interval of the off-state; actuating the control value to transition from an off-state to an on-state; then detecting the arrival of the plunger at the wellhead prior to expiration of the predetermined value for the time interval of the on-state, and determining the time elapsed from the actuation; determining the presence of any coincidence of the time elapsed from the actuation of the control valve with the assigned second values; then increasing the predetermined value for the time interval of the off-state by a predetermined first time increment when a the coincidence with the assigned second value is present; and terminating the the on-state in response to the plunger detection, and actuating the control valve to transition from the on-state to the next off-state in response to the termination of the on-state.
Bray, L.A.; DesChane, J.R.
1998-05-05
A method is described for separating {sup 213}Bi from a solution of radionuclides wherein the solution contains a concentration of the chloride ions and hydrogen ions adjusted to allow the formation of a chloride complex. The solution is then brought into contact with an anion exchange resin, whereupon {sup 213}Bi is absorbed from the solution and adhered onto the anion exchange resin in the chloride complex. Other non-absorbing radionuclides such as {sup 225}Ra, {sup 225}Ac, and {sup 221}Fr, along with HCl are removed from the anion exchange resin with a scrub solution. The {sup 213}Bi is removed from the anion exchange resin by washing the anion exchange resin with a stripping solution free of chloride ions and with a reduced hydrogen ion concentration which breaks the chloride anionic complex, releasing the {sup 213}Bi as a cation. In a preferred embodiment of the present invention, the anion exchange resin is provided as a thin membrane, allowing for extremely rapid adherence and stripping of the {sup 213}Bi. A preferred stripping solution for purification of {sup 213}Bi for use in medical applications includes sodium acetate, pH 5.5. A protein conjugated with bifunctional chelating agents in vivo with the NaOAc receives the {sup 213}Bi as it is being released from the anion exchange resin. 10 figs.
Method of turbocharger control
Lyon, K.M.
1990-10-09
This patent describes a method of turbocharger control in a vehicle having an engine and a turbocharger for increasing the density of at least the air entering a cylinder of the engine. The turbocharger has at least a compressor and a turbine coupled by a shaft and a nozzle to increase the angular momentum of the flow of gas to the turbine. The nozzle has a housing and movable vanes to vary the angle and velocity that the exhaust gas hits the wheel of the turbine, and actuator for moving the vanes, a can separated by a diaphragm and having an A side and B side for actuating the actuator, solenoid-actuated valves for controlling the pressure in the A and B sides of the can, an electronic control unit (ECU) having memory for storing data and predetermined values and for actuating and de-actuating the solenoid-actuated valves, a plurality of inputs to the ECU for providing input data indicative of engine temperature, engine speed, vehicle speed, intake manifold pressure, throttle angle, engine knock and charge air temperature.
Nonlinear Attitude Filtering Methods
NASA Technical Reports Server (NTRS)
Markley, F. Landis; Crassidis, John L.; Cheng, Yang
2005-01-01
This paper provides a survey of modern nonlinear filtering methods for attitude estimation. Early applications relied mostly on the extended Kalman filter for attitude estimation. Since these applications, several new approaches have been developed that have proven to be superior to the extended Kalman filter. Several of these approaches maintain the basic structure of the extended Kalman filter, but employ various modifications in order to provide better convergence or improve other performance characteristics. Examples of such approaches include: filter QUEST, extended QUEST, the super-iterated extended Kalman filter, the interlaced extended Kalman filter, and the second-order Kalman filter. Filters that propagate and update a discrete set of sigma points rather than using linearized equations for the mean and covariance are also reviewed. A two-step approach is discussed with a first-step state that linearizes the measurement model and an iterative second step to recover the desired attitude states. These approaches are all based on the Gaussian assumption that the probability density function is adequately specified by its mean and covariance. Other approaches that do not require this assumption are reviewed, including particle filters and a Bayesian filter based on a non-Gaussian, finite-parameter probability density function on SO(3). Finally, the predictive filter, nonlinear observers and adaptive approaches are shown. The strengths and weaknesses of the various approaches are discussed.
Backus, S.; Kapteyn, H.C.; Murnane, M.M.
1997-07-01
Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethrough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate. 7 figs.
Backus, Sterling; Kapteyn, Henry C.; Murnane, Margaret M.
1997-01-01
Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate.
Teaching Stable Two-Mirror Resonators through the Fractional Fourier Transform
ERIC Educational Resources Information Center
Moreno, Ignacio; Garcia-Martinez, Pascuala; Ferreira, Carlos
2010-01-01
We analyse two-mirror resonators in terms of their fractional Fourier transform (FRFT) properties. We use the basic ABCD ray transfer matrix method to show how the resonator can be regarded as the cascade of two propagation-lens-propagation FRFT systems. Then, we present a connection between the geometric properties of the resonator (the g…
NASA Technical Reports Server (NTRS)
David, J. W.; Mitchell, L. D.
1982-01-01
Difficulties in solution methodology to be used to deal with the potentially higher nonlinear rotor equations when dynamic coupling is included. A solution methodology is selected to solve the nonlinear differential equations. The selected method was verified to give good results even at large nonlinearity levels. The transfer matrix methodology is extended to the solution of nonlinear problems.
Off-diagonal Bethe ansatz solution of the XXX spin chain with arbitrary boundary conditions
NASA Astrophysics Data System (ADS)
Cao, Junpeng; Yang, Wen-Li; Shi, Kangjie; Wang, Yupeng
2013-10-01
Employing the off-diagonal Bethe ansatz method proposed recently by the present authors, we exactly diagonalize the XXX spin chain with arbitrary boundary fields. By constructing a functional relation between the eigenvalues of the transfer matrix and the quantum determinant, the associated T-Q relation and the Bethe ansatz equations are derived.
Züttel, Andreas
2004-04-01
Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. There are two reasons why hydrogen is not the major fuel of today's energy consumption. First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water and hydrocarbons. This implies that we have to pay for the energy, which results in a difficult economic dilemma because ever since the industrial revolution we have become used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is its low critical temperature of 33 K (i.e. hydrogen is a gas at ambient temperature). For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage material is crucial. Hydrogen can be stored using six different methods and phenomena: (1) high-pressure gas cylinders (up to 800 bar), (2) liquid hydrogen in cryogenic tanks (at 21 K), (3) adsorbed hydrogen on materials with a large specific surface area (at T<100 K), (4) absorbed on interstitial sites in a host metal (at ambient pressure and temperature), (5) chemically bonded in covalent and ionic compounds (at ambient pressure), or (6) through oxidation of reactive metals, e.g. Li, Na, Mg, Al, Zn with water. The most common storage systems are high-pressure gas cylinders with a maximum pressure of 20 MPa (200 bar). New lightweight composite cylinders have been developed which are able to withstand pressures up to 80 MPa (800 bar) and therefore the hydrogen gas can reach a volumetric density of 36 kg.m(-3), approximately half as much as in its liquid state. Liquid hydrogen is stored in cryogenic tanks at 21.2 K and ambient pressure. Due to the low critical temperature of hydrogen (33 K), liquid hydrogen can only be stored in open systems. The volumetric density of liquid hydrogen
NASA Astrophysics Data System (ADS)
Züttel, Andreas
Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. There are two reasons why hydrogen is not the major fuel of today's energy consumption. First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water and hydrocarbons. This implies that we have to pay for the energy, which results in a difficult economic dilemma because ever since the industrial revolution we have become used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is its low critical temperature of 33 K (i.e. hydrogen is a gas at ambient temperature). For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage material is crucial. Hydrogen can be stored using six different methods and phenomena: (1) high-pressure gas cylinders (up to 800 bar), (2) liquid hydrogen in cryogenic tanks (at 21 K), (3) adsorbed hydrogen on materials with a large specific surface area (at T<100 K), (4) absorbed on interstitial sites in a host metal (at ambient pressure and temperature), (5) chemically bonded in covalent and ionic compounds (at ambient pressure), or (6) through oxidation of reactive metals, e.g. Li, Na, Mg, Al, Zn with water. The most common storage systems are high-pressure gas cylinders with a maximum pressure of 20 MPa (200 bar). New lightweight composite cylinders have been developed which are able to withstand pressures up to 80 MPa (800 bar) and therefore the hydrogen gas can reach a volumetric density of 36 kg.m-3, approximately half as much as in its liquid state. Liquid hydrogen is stored in cryogenic tanks at 21.2 K and ambient pressure. Due to the low critical temperature of hydrogen (33 K), liquid hydrogen can only be stored in open systems. The volumetric density of liquid hydrogen is
Kugel, H. W.; Spong, D.; Majeski, R.; Zarnstorff, M.
2008-01-18
The National Compact Stellarator Experiment (NCSX) has been designed to accommodate a variety of heating systems, including ohmic heating, neutral beam injection, and radio-frequency (rf). Neutral beams will provide one of the primary heating methods for NCSX. In addition to plasma heating, neutral beams are also expected to provide a means for external control over the level of toroidal plasma rotation velocity and its profile. The experimental plan requires 3 MW of 50-keV balanced neutral beam tangential injection with pulse lengths of 500 ms for initial experiments, to be upgradeable to pulse lengths of 1.5 s. Subsequent upgrades will add 3MW of neutral beam injection (NBI). This paper discusses the NCSX NBI requirements and design issues and shows how these are provided by the candidate PBX-M NBI system. In addition, estimations are given for beam heating efficiencies, scaling of heating efficiency with machine size and magnetic field level, parameter studies of the optimum beam injection tangency radius and toroidal injection location, and loss patterns of beam ions on the vacuum chamber wall to assist placement of wall armor and for minimizing the generation of impurities by the energetic beam ions. Finally, subsequent upgrades could add an additional 6 MW of rf heating by mode conversion ion Bernstein wave (MCIBW) heating, and if desired as possible future upgrades, the design also will accommodate high-harmonic fast-wave and electron cyclotron heating. The initial MCIBW heating technique and the design of the rf system lend themselves to current drive, so if current drive became desirable for any reason, only minor modifications to the heating system described here would be needed. The rf system will also be capable of localized ion heating (bulk or tail), and possiblyIBW-generated sheared flows.
H.W. Kugel; D. Spong; R. Majeski; M. Zarnstorff
2003-02-28
The NCSX (National Compact Stellarator Experiment) has been designed to accommodate a variety of heating systems, including ohmic heating, neutral-beam injection, and radio-frequency. Neutral beams will provide one of the primary heating methods for NCSX. In addition to plasma heating, beams are also expected to provide a means for external control over the level of toroidal plasma rotation velocity and its profile. The plan is to provide 3 MW of 50 keV balanced neutral-beam tangential injection with pulse lengths of 500 msec for initial experiments, and to be upgradeable to pulse lengths of 1.5 sec. Subsequent upgrades will add 3 MW of neutral-beam injection. This Chapter discusses the NCSX neutral-beam injection requirements and design issues, and shows how these are provided by the candidate PBX-M (Princeton Beta Experiment-Modification) neutral-beam injection system. In addition, estimations are given for beam-heating efficiencies, scaling of heating efficiency with machine size an d magnetic field level, parameter studies of the optimum beam-injection tangency radius and toroidal injection location, and loss patterns of beam ions on the vacuum chamber wall to assist placement of wall armor and for minimizing the generation of impurities by the energetic beam ions. Finally, subsequent upgrades could add an additional 6 MW of radio-frequency heating by mode-conversion ion-Bernstein wave (MCIBW) heating, and if desired as possible future upgrades, the design also will accommodate high-harmonic fast-wave and electron-cyclotron heating. The initial MCIBW heating technique and the design of the radio-frequency system lend themselves to current drive, so that if current drive became desirable for any reason only minor modifications to the heating system described here would be needed. The radio-frequency system will also be capable of localized ion heating (bulk or tail), and possibly ion-Bernstein-wave-generated sheared flows.
Slope stability and stabilization methods
Abramson, L.W.; Lee, T.S.; Boyce, G.M.; Sharma, S.S.
1995-12-01
Slope stability can be a major problem during the construction of surface facilities. Cutting into existing ground disturbs the mechanics of the surrounding area, which can result in landslides and rock falls. This practical reference gives you the comprehensive information you need for slope stability analysis, suitable methods of analysis with and without the use of computers, and examples of common stability problems and stabilization methods for cuts and fills. It includes detailed discussions of methods used in slope stability analysis, including the Ordinary Method of Slices, Simplified Janbu Method, Simplified Bishop Method, Spencer`s Method, other limit equilibrium methods, numerical methods, total stress analysis, effective stress analysis, and the use of computer programs to solve problems. Chapters include: General Slope Stability Concepts; Engineering Geology Principles; Groundwater Conditions; Geologic Site Exploration; Laboratory Testing Interpretation; Slope Stability Concepts; Slope Stabilization Methods; and Design, Construction and Maintenance.
An Extended Method of SIRMs Connected Fuzzy Inference Method Using Kernel Method
NASA Astrophysics Data System (ADS)
Seki, Hirosato; Mizuguchi, Fuhito; Watanabe, Satoshi; Ishii, Hiroaki; Mizumoto, Masaharu
The single input rule modules connected fuzzy inference method (SIRMs method) by Yubazaki et al. can decrease the number of fuzzy rules drastically in comparison with the conventional fuzzy inference methods. Moreover, Seki et al. have proposed a functional-type SIRMs method which generalizes the consequent part of the SIRMs method to function. However, these SIRMs methods can not be applied to XOR (Exclusive OR). In this paper, we propose a “kernel-type SIRMs method” which uses the kernel trick to the SIRMs method, and show that this method can treat XOR. Further, a learning algorithm of the proposed SIRMs method is derived by using the steepest descent method, and compared with the one of conventional SIRMs method and kernel perceptron by applying to identification of nonlinear functions, medical diagnostic system and discriminant analysis of Iris data.
Variable metric conjugate gradient methods
Barth, T.; Manteuffel, T.
1994-07-01
1.1 Motivation. In this paper we present a framework that includes many well known iterative methods for the solution of nonsymmetric linear systems of equations, Ax = b. Section 2 begins with a brief review of the conjugate gradient method. Next, we describe a broader class of methods, known as projection methods, to which the conjugate gradient (CG) method and most conjugate gradient-like methods belong. The concept of a method having either a fixed or a variable metric is introduced. Methods that have a metric are referred to as either fixed or variable metric methods. Some relationships between projection methods and fixed (variable) metric methods are discussed. The main emphasis of the remainder of this paper is on variable metric methods. In Section 3 we show how the biconjugate gradient (BCG), and the quasi-minimal residual (QMR) methods fit into this framework as variable metric methods. By modifying the underlying Lanczos biorthogonalization process used in the implementation of BCG and QMR, we obtain other variable metric methods. These, we refer to as generalizations of BCG and QMR.
Multiple Methods: Research Methods in Education Projects at NSF
ERIC Educational Resources Information Center
Suter, Larry E.
2005-01-01
Projects on science and mathematics education research supported by the National Science Foundation (US government) rarely employ a single method of study. Studies of educational practices that use experimental design are very rare. The most common research method is the case study method and the second most common is some form of experimental…
Analytic Methods in Investigative Geometry.
ERIC Educational Resources Information Center
Dobbs, David E.
2001-01-01
Suggests an alternative proof by analytic methods, which is more accessible than rigorous proof based on Euclid's Elements, in which students need only apply standard methods of trigonometry to the data without introducing new points or lines. (KHR)
Production Methods in Industrial Microbiology.
ERIC Educational Resources Information Center
Gaden, Elmer L., Jr.
1981-01-01
Compares two methods (batch and continuous) in which microorganisms are used to produce industrial chemicals. Describes batch and continuous stirred-tank reactors and offers reasons why the batch method may be preferred. (JN)
Comparison of Artificial Compressibility Methods
NASA Technical Reports Server (NTRS)
Kiris, Cetin; Housman, Jeffrey; Kwak, Dochan
2004-01-01
Various artificial compressibility methods for calculating the three-dimensional incompressible Navier-Stokes equations are compared. Each method is described and numerical solutions to test problems are conducted. A comparison based on convergence behavior, accuracy, and robustness is given.
Integrated force method versus displacement method for finite element analysis
NASA Technical Reports Server (NTRS)
Patnaik, Surya N.; Berke, Laszlo; Gallagher, Richard H.
1990-01-01
A novel formulation termed the integrated force method (IFM) has been developed in recent years for analyzing structures. In this method all the internal forces are taken as independent variables, and the system equilibrium equations (EE's) are integrated with the global compatibility conditions (CC's) to form the governing set of equations. In IFM the CC's are obtained from the strain formulation of St. Venant, and no choices of redundant load systems have to be made, in constrast to the standard force method (SFM). This property of IFM allows the generation of the governing equation to be automated straightforwardly, as it is in the popular stiffness method (SM). In this report IFM and SM are compared relative to the structure of their respective equations, their conditioning, required solution methods, overall computational requirements, and convergence properties as these factors influence the accuracy of the results. Overall, this new version of the force method produces more accurate results than the stiffness method for comparable computational cost.
Optical measurement methods in thermogasdynamics
NASA Technical Reports Server (NTRS)
Stursberg, K.; Erhardt, K.; Krahr, W.; Becker, M.
1978-01-01
A review is presented of a number of optical methods of flow measurements. Consideration is given to such spectroscopic methods as emission and absorption techniques, electron beam-stimulated fluorescence, and light scattering - Rayleigh, Raman and Mie - methods. The following visualization methods are also discussed: shadow photography, schlieren photography, interferometry, holographic interferometry, laser anemometry, particle holography, and electron-excitation imaging. A large bibliography is presented and the work is copiously illustrated with figures and photographs.
NASA Technical Reports Server (NTRS)
Hornstein, J.; Fainberg, J.
1981-01-01
We review ray-optical methods of analyzing short-wavelength propagation in random media. The advantages and limitations of ray methods are discussed, and results of the statistical theory of ray segment fluctuations pertinent to ray tracing are summarized. The standard method of Monte Carlo ray tracing is compared to a new method which takes into account recent results on the statistics of ray segment fluctuations.
Comparison of Artificial Compressibility Methods
NASA Technical Reports Server (NTRS)
Kiris, Cetin; Housman, Jeffrey; Kwak, Dochan
2003-01-01
Various artificial compressibility methods for calculating three-dimensional, steady and unsteady, laminar and turbulent, incompressible Navier-Stokes equations are compared in this work. Each method is described in detail along with appropriate physical and numerical boundary conditions. Analysis of well-posedness and numerical solutions to test problems for each method are provided. A comparison based on convergence behavior, accuracy, stability and robustness is used to establish the relative positive and negative characteristics of each method.
Spectral methods on arbitrary grids
NASA Technical Reports Server (NTRS)
Carpenter, Mark H.; Gottlieb, David
1995-01-01
Stable and spectrally accurate numerical methods are constructed on arbitrary grids for partial differential equations. These new methods are equivalent to conventional spectral methods but do not rely on specific grid distributions. Specifically, we show how to implement Legendre Galerkin, Legendre collocation, and Laguerre Galerkin methodology on arbitrary grids.
Methods of making textured catalysts
Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.
2010-08-17
A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.
Alternate Methods of Teaching Psychopharmacology
ERIC Educational Resources Information Center
Zisook, Sidney; Benjamin, Sheldon; Balon, Richard; Glick, Ira; Louie, Alan; Moutier, Christine; Moyer, Trenton; Santos, Cynthia; Servis, Mark
2005-01-01
Objective: This article reviews methods used to teach psychopharmacology to psychiatry residents that utilize principles of adult learning, enlist active participation of residents, and provide faculty with skills to seek, analyze, and use new information over the course of their careers. Methods: The pros and cons of five "nonlecture" methods of…
Generalized high order compact methods.
Spotz, William F.; Kominiarczuk, Jakub
2010-09-01
The fundamental ideas of the high order compact method are combined with the generalized finite difference method. The result is a finite difference method that works on unstructured, nonuniform grids, and is more accurate than one would classically expect from the number of grid points employed.
Linguistic Method: Yesterday and Today.
ERIC Educational Resources Information Center
Rauch, Irmengard
This paper introduces the reader to a brief history of the focus of linguistic method from prehistoric times, through the Classical era, the Middle Ages, to the present. The scientific orientation of linguistic method is exploited; a set of specific principles is found to unify most of today's diverse methods. The success of linguistics is…
The Discovery Method in Training.
ERIC Educational Resources Information Center
Belbin, R. M.
In the form of a discussion between faceless people, this booklet concerns discovery learning and its advantages. Subjects covered in the discussions are: Introducing the Discovery Method; An Experiment with British Railways; The OECD Research Projects in U.S.A., Austria, and Sweden; How the Discovery Method Differs from Other Methods; Discovery…
Indirect methods in nuclear astrophysics
NASA Astrophysics Data System (ADS)
Bertulani, C. A.; Shubhchintak; Mukhamedzhanov, A.; Kadyrov, A. S.; Kruppa, A.; Pang, D. Y.
2016-04-01
We discuss recent developments in indirect methods used in nuclear astrophysics to determine the capture cross sections and subsequent rates of various stellar burning processes, when it is difficult to perform the corresponding direct measurements. We discuss in brief, the basic concepts of Asymptotic Normalization Coefficients, the Trojan Horse Method, the Coulomb Dissociation Method, (d,p), and charge-exchange reactions.
NASA Astrophysics Data System (ADS)
Abidin, Zubai'ah Zainal; Mamat, Mustafa; Rivaie, Mohd; Mohd, Ismail
2014-06-01
The classical steepest descent (SD) method is known as one of the earliest and the best method to minimize a function. Even though the convergence rate is quite slow, but its simplicity has made it one of the easiest methods to be used and applied especially in the form of computer codes. In this paper, a new modification of SD method is proposed using a new search direction (dk) in the form of two parameters. Numerical results shows that this new SD has far superior convergence rate and more efficient than the classical SD method.
Immersed interface methods. Final report
LeVeque, R.J.; Adams, L.M.; Bube, K.P.
1996-11-01
Cartesian grid methods encompass a wide variety of techniques used to solve partial differential equations in more than one space dimension on uniform Cartesian grids even when the underlying geometry is complex and not aligned with the grid. The authors` groups work on Immersed Interface Methods (IIM) was originally motivated by the desire to understand and improve the ``Immersed Boundary Method``, developed by Charles Peskin to solve incompressible Navier-Stokes equations in complicated geometries with moving elastic boundaries. This report briefly discusses the development of the Immersed Interface Methods and gives examples of application of the method in solving several partial differential equations.
Method for isolating nucleic acids
Hurt, Jr., Richard Ashley; Elias, Dwayne A.
2015-09-29
The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.
Excitation Methods for Bridge Structures
Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.
1999-02-08
This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.
Methods for purifying carbon materials
Dailly, Anne; Ahn, Channing; Yazami, Rachid; Fultz, Brent T.
2009-05-26
Methods of purifying samples are provided that are capable of removing carbonaceous and noncarbonaceous impurities from a sample containing a carbon material having a selected structure. Purification methods are provided for removing residual metal catalyst particles enclosed in multilayer carbonaceous impurities in samples generate by catalytic synthesis methods. Purification methods are provided wherein carbonaceous impurities in a sample are at least partially exfoliated, thereby facilitating subsequent removal of carbonaceous and noncarbonaceous impurities from the sample. Methods of purifying carbon nanotube-containing samples are provided wherein an intercalant is added to the sample and subsequently reacted with an exfoliation initiator to achieve exfoliation of carbonaceous impurities.