Academic literature on the topic 'R-matrix technique'
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Journal articles on the topic "R-matrix technique"
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Kuroda, Shoichi, Masayuki Arai, and Kiyohiro Ito. "Transfer Matrix Analysis for Curved Beam Structure." Key Engineering Materials 774 (August 2018): 131–36. http://dx.doi.org/10.4028/www.scientific.net/kem.774.131.
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The curved beam structure such as pipe system has been widely used in industrial plants or power stations. In this study, the reduction technique of stiffness matrix, which is refered to “transfer matrix method (TM)“, is developed to solve effectively the problem. For achieving the purpose, the transfer matrix Fk to transfer deformation, rotation, force and moment from node i to node i+1, which are named for both edges in k-th beam element, is formulated. The global transfer matrix is then constructed by multiplying as R(θk+1,k)·Fk···R(θ2,1)·F1···R(θk+1,k) is the coordinate rotation matrix. The efficiency and simplicity of this method is demonstrated by solving the problem of a curved pipe line with elbow which is subjected to external forces and displacements. The results are compared with those obtained by FEM.
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Lau, Terry, and Chik Tan. "A New Technique in Rank Metric Code-Based Encryption." Cryptography 2, no. 4 (October 15, 2018): 32. http://dx.doi.org/10.3390/cryptography2040032.
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We propose a rank metric codes based encryption based on the hard problem of rank syndrome decoding problem. We propose a new encryption with a public key matrix by considering the adding of a random distortion matrix over F q m of full column rank n. We show that IND-CPA security is achievable for our encryption under assumption of the Decisional Rank Syndrome Decoding problem. Furthermore, we also prove some bounds for the number of matrices of a fixed rank with entries over a finite field. Our proposal allows the choice of the error terms with rank up to r 2 , where r is the error-correcting capability of a code. Our encryption based on Gabidulin codes has public key size of 13 . 68 KB, which is 82 times smaller than the public key size of McEliece Cryptosystem based on Goppa codes. For similar post-quantum security level of 2 140 bits, our encryption scheme has a smaller public key size than the key size suggested by LOI17 Encryption.
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Szutkowska, Magdalena, Marek Boniecki, and Mirosław M. Bućko. "R-Curve Behaviour of Alumina Matrix Ceramics with Long Cracks." Advances in Science and Technology 45 (October 2006): 1652–57. http://dx.doi.org/10.4028/www.scientific.net/ast.45.1652.
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The R-curve (KR versus crack length c) behavior has been examined in alumina-10 wt% zirconia ceramics with 3 mol% yttria stabilized zirconia, alumina-10 wt% zirconia ceramics with 12 mol% nano ceria stabilized zirconia and Al2O3-30 wt% Ti(C,N) ceramics. An observation of in situ microscopic long-through thickness crack growth during three point bending (3PB) of a single edge notched beam (SENB) enabled measurement of the R-curve. It was found that both aluminazirconia ceramics with yttria or ceria stabilized zirconia exhibit a rising R-curve while for Al2O3-30 wt% Ti(C,N) ceramics such relationship was not observed. Moreover the slow crack growth parameters (n, logA) were determined by means of load-relaxation technique for tested alumina matrix ceramics.
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Zeb, Salman, Muhammad Yousaf, Aziz Khan, Bahaaeldin Abdalla, and Thabet Abdeljawad. "Updating $ QR $ factorization technique for solution of saddle point problems." AIMS Mathematics 8, no. 1 (2023): 1672–81. http://dx.doi.org/10.3934/math.2023085.
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<abstract><p>We consider saddle point problem and proposed an updating $ QR $ factorization technique for its solution. In this approach, instead of working with large system which may have a number of complexities such as memory consumption and storage requirements, we computed $ QR $ factorization of matrix $ A $ and then updated its upper triangular factor $ R $ by appending the matrices $ B $ and $ \left(\begin{array}{cc} B^T & -C \\ \end{array} \right) $ to obtain the solution. The $ QR $ factorization updated process consisting of updating of the upper triangular factor $ R $ and avoid the involvement of orthogonal factor $ Q $ due to its expensive storage requirements. This technique is also suited as an updating strategy when $ QR $ factorization of matrix $ A $ is available and it is required that matrices of similar nature be added to its right end or at bottom position for solving the modified problems. Numerical tests are carried out to demonstrate the applications and accuracy of the proposed approach.</p></abstract>
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El-Sayed, Ehab A., and Eid E. El Behady. "Algorithms for Solving Nonhomogeneous Generalized Sylvester Matrix Equations." Mathematical Problems in Engineering 2020 (March 31, 2020): 1–5. http://dx.doi.org/10.1155/2020/1549520.
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This paper considers a new method to solve the first-order and second-order nonhomogeneous generalized Sylvester matrix equations AV+BW= EVF+R and MVF2+DV F+KV=BW+R, respectively, where A,E,M,D,K,B, and F are the arbitrary real known matrices and V and W are the matrices to be determined. An explicit solution for these equations is proposed, based on the orthogonal reduction of the matrix F to an upper Hessenberg form H. The technique is very simple and does not require the eigenvalues of matrix F to be known. The proposed method is illustrated by numerical examples.
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Başcı, Yasemin, and Aydın Tiryaki. "Oscillation results for second order matrix differential equations with damping." Filomat 31, no. 15 (2017): 4749–62. http://dx.doi.org/10.2298/fil1715749b.
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By using the positive linear functional, including the general means and Riccati technique, some new oscillation criteria are established for the second order matrix differential equations (r(t)P(t)?(X(t))K(X'(t)))' + p(t)R(t)?(X(t))K(X'(t)) + Q(t)F(X'(t))G(X(t)) = 0,t ? t0 > 0. The results improve and generalize those given in some previous papers.
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ZHOU, RUGUANG, and ZHENYUN QIN. "AN INTEGRABLE DECOMPOSITION OF THE SYMMETRIC MATRIX KdV EQUATION." Modern Physics Letters B 22, no. 13 (May 30, 2008): 1307–15. http://dx.doi.org/10.1142/s0217984908015383.
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A technique for nonlinearization of the Lax pair for the scalar soliton equations in (1+1) dimensions is applied to the symmetric matrix KdV equation. As a result, a pair of finite-dimensional integrable Hamiltonian systems, which are of higher rank generalization of the classic Gaudin models, are obtained. The integrability of the systems are shown by the explicit Lax representations and r-matrix method.
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Abdolsalami, Farzan, Mehran Abdolsalami, Lennard Perez, Pedro Gomez, and Mark Silva. "Study of electron—molecule collision via finite-element method and R-matrix propagation technique: Exact exchange." Journal of Computational Physics 121, no. 2 (October 1995): 314–23. http://dx.doi.org/10.1016/s0021-9991(95)90153-1.
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Chen, J. T., Y. L. Chang, S. Y. Leu, and J. W. Lee. "Static Analysis of the Free-Free Trusses by Using a Self-Regularization Approach." Journal of Mechanics 34, no. 4 (March 29, 2017): 505–18. http://dx.doi.org/10.1017/jmech.2017.15.
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AbstractFollowing the success of static analysis of free-free 2-D plane trusses by using a self-regularization approach uniquely, we further extend the technique to deal with 3-D problems of space trusses. The inherent singular stiffness of a free-free structure is expanded to a bordered matrix by adding r singular vectors corresponding to zero singular values, where r is the nullity of the singular stiffness matrix. Besides, r constraints are accompanied to result in a nonsingular matrix. Only the pure particular solution with nontrivial strain is then obtained but without the homogeneous solution of no deformation. To link with the Fredholm alternative theorem, the slack variables with zero values indicate the infinite solutions while those with nonzero values imply the case of no solutions. A simple space truss is used to demonstrate the validity of the proposed model. An alternative way of reasonable support system to result in a nonsingular stiffness matrix is also addressed. In addition, the finite-element commercial code ABAQUS is also implemented to check the results.
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Sbaizero, O., and G. Pezzotti. "Tailoring the Microstructure of a Metal-Reinforced Ceramic Matrix Composite." Journal of Engineering Materials and Technology 122, no. 3 (March 16, 2000): 363–67. http://dx.doi.org/10.1115/1.482810.
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Alumina matrix was prepared with varying amounts of metal molybdenum particles of two different grain sizes. R-curves were determined during stable crack propagation and a piezo-spectroscopic technique was used to assess the bridging stresses developed along the crack wake (at the metal/matrix interface) at the critical condition for crack propagation. In both kinds of composites, the toughness monotonically increases with the amount of molybdenum added. In addition, bridging stress and therefore toughness were higher when coarser particles were present. The theoretical R-curves calculated from the discrete (microscopic) bridging stress distribution obtained by in situ Raman spectroscopy were in good agreement with the experimental data. [S0094-4289(00)02003-X]
Dissertations / Theses on the topic "R-matrix technique"
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Went, Michael Ray, and n/a. "Scattering of Spin Polarized Electrons from Heavy Atoms: Krypton and Rubidium." Griffith University. School of Science, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040220.134142.
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This thesis presents a set of measurements of spin asymmetries from the heavy atoms krypton and rubidium. These investigations allow examination of the spin orbit interaction for electron scattering from the target atoms. These measurements utilise spin polarized electrons in a crossed beam experiment to measure the Sherman function from krypton and the A2 parameter from the 52P state of rubidium. The measurements utilise a new spin polarized electron energy spectrometer which is designed to operate in the 20-200 eV range. The apparatus consists of a standard gallium arsenide polarized electron source, a 180 degrees hemispherical electron analyser to detect scattered electrons and a Mott detector to measure electron polarization. A series of measurements of the elastic Sherman function were performed on krypton at incident electron energies of 20, 50, 60, 65, 100, 150 and 200 eV. Scattered electrons are measured over an angular range of 30-130 degrees. These measurements are compared with calculations of the Sherman function which are obtained by solution of the Dirac-Fock equations. These calculations include potentials to account for dynamic polarization and loss of flux into inelastic channels. At the energies 50, 60 and 65 eV, experimental agreement with theory is seen to be extremely dependent on the theoretical model used. Measurement of the A2 parameter from the combined 52P1/2,3/2 state of rubidium are performed at an incident energy of 20 eV. The scattered electrons are measured over an angular range of 30-110 degrees. This measurement represents the first such measurement of this parameter for rubidium. Agreement with preliminary calculations performed using the R-matrix technique are good and are expected to improve with further theoretical development.
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Went, Michael Ray. "Scattering of Spin Polarized Electrons from Heavy Atoms: Krypton and Rubidium." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/365606.
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This thesis presents a set of measurements of spin asymmetries from the heavy atoms krypton and rubidium. These investigations allow examination of the spin orbit interaction for electron scattering from the target atoms. These measurements utilise spin polarized electrons in a crossed beam experiment to measure the Sherman function from krypton and the A2 parameter from the 52P state of rubidium. The measurements utilise a new spin polarized electron energy spectrometer which is designed to operate in the 20-200 eV range. The apparatus consists of a standard gallium arsenide polarized electron source, a 180 degrees hemispherical electron analyser to detect scattered electrons and a Mott detector to measure electron polarization. A series of measurements of the elastic Sherman function were performed on krypton at incident electron energies of 20, 50, 60, 65, 100, 150 and 200 eV. Scattered electrons are measured over an angular range of 30-130 degrees. These measurements are compared with calculations of the Sherman function which are obtained by solution of the Dirac-Fock equations. These calculations include potentials to account for dynamic polarization and loss of flux into inelastic channels. At the energies 50, 60 and 65 eV, experimental agreement with theory is seen to be extremely dependent on the theoretical model used. Measurement of the A2 parameter from the combined 52P1/2,3/2 state of rubidium are performed at an incident energy of 20 eV. The scattered electrons are measured over an angular range of 30-110 degrees. This measurement represents the first such measurement of this parameter for rubidium. Agreement with preliminary calculations performed using the R-matrix technique are good and are expected to improve with further theoretical development.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
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Chen, Huiqiang 1967. "Fabrication of magnesium matrix composites using a spontaneous infiltration technique." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79222.
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A new process was developed to fabricate particulate metal matrix composites (MMCs). The process involves two steps: (1) forming a particulate porous compact, and (2) introducing molten magnesium or magnesium alloy (AZ91) into the channel network by a spontaneous infiltration technique.A uniform distribution of SiC particulates in magnesium matrix was achieved. Microsegregation existed in composites when the particle size of reinforcement was 38 mum and 22 mum, however, when the particle size of reinforcement was 12 mum, the microsegregation was eliminated.
The interfacial reaction between SiC and Mg studied by Scanning Electron Microscopy (SEM), microanalysis, and X-Ray Diffraction (XRD) techniques showed that, Mg reacted with Si or SiO2 to form Mg2Si, Mg 2Si was present at the surface of SiC after precipitation, resulting in improved wettability between Mg and SiC. As a result of this interfacial reaction, the infiltration process became spontaneous. The infiltration process was related to the infiltration temperature, SiC particle size and matrix chemistry. Increasing the infiltration temperature, decreasing the particle size of SiC resulted in more successful infiltration.
Mechanical testing conducted on composites revealed that the hardness and Ultimate Tensile Strength (UTS) of composites increased with the decrease of particle size of SiC and corresponded to an increase of the volume fraction of SiC.
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Toumazou, Vincent. "Portraits spectraux de matrices : un outil d'analyse de la stabilité." Nancy 1, 1996. http://www.theses.fr/1996NAN10273.
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La détermination des valeurs propres et/ou des vecteurs propres de matrices de grande taille occupe une place importante dans le calcul scientifique. Cependant, le traitement numérique de problèmes physiques couples génère souvent des problèmes de valeurs propres de grande taille non-normaux qui peuvent alors exhiber de l'instabilité spectrale. Il est crucial pour le scientifique de disposer d'outils capables de détecter et/ou de mesurer l'instabilité spectrale des matrices qu'il utilise et de prédire et/ou quantifier les perturbations résultant sur la solution calculée a précision finie. Ce document passe en revue les outils théoriques classiques utilises dans l'estimation de l'erreur et montre leurs limites en présence d'instabilité spectrale forte. La non-normalité et ses liens avec l'instabilité spectrale sont particulièrement détaillés: la taxonomie établie permet de clarifier les notions de matrices normales et fortement non-normales. Nous montrons comment les quantificateurs classiques de la non-normalité ne parviennent pas à prédire de manière satisfaisante l'instabilité spectrale. Une alternative basée sur les pseudospectres est alors proposée dans le cas des matrices et des faisceaux de matrices. Nous étudions la représentation des pseudospectres par des portraits spectraux ainsi que les différentes interprétations qui peuvent en être faites à partir de nombreux exemples notamment issus de la physique. On peut ainsi comprendre comment les portraits spectraux permettent de visualiser l'instabilité spectrale qui découle de la non-normalité. Enfin, différentes méthodes numériques pour le calcul des portraits spectraux sont exposées. L’implantation informatique de la méthode retenue, celle de l'équation normale, est détaillée dans le cadre d'une architecture parallèle à mémoire distribuée, rendant cet outil utilisable dans un cadre industriel.
Book chapters on the topic "R-matrix technique"
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Noble, C. J. "R-Matrix Techniques for Intermediate Energy Scattering and Photoionization." In Computational Methods for Electron—Molecule Collisions, 309–26. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4757-9797-8_14.
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Quibell, Martin, and Tony Johnson. "Difficult peptides." In Fmoc Solid Phase Peptide Synthesis. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780199637256.003.0009.
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Solid phase peptide synthesis (SPPS), first proposed by R. B. Merrifield in 1962, has evolved over three decades into a tremendously powerful method for the preparation of peptides and small proteins. An absolute prerequisite for successful syntheses in all solid phase schemes is that reactions which accumulate solid supported products, and by the very nature of the technique contaminating by-products, must proceed cleanly and efficiently. During the earlier years of SPPS this optimal situation was not always achieved, primarily due to contaminated reagents and ill-defined polymers in combination with poorly flexible protection strategies. As the methods of SPPS gained popularity and more widespread application, reagents and protection strategies were improved and refined. However, reports of notable successful syntheses were accompanied by then unexplained failures, which have since been collectively termed ‘difficult peptides’. This chapter describes how an intrinsic understanding behind the occurrence of ‘difficult peptides’ has accumulated, leading to a general synthetic solution—the utilization of a backbone amide protection strategy. Within a few years of the introduction of SPPS, it was recognized that the assembly of some peptide sequences posed a special synthetic problem. The main feature evident during these syntheses was a sudden decrease in reaction kinetics, leading to incomplete amino-acylation by activated amino acid residues. The unreacted sites were readily detected by the Kaiser test for free amine; however, couplings showed no significant improvement even upon repeated or prolonged reaction. Efficient reactions are known to occur within a fully solvated peptide-polymer matrix, where reagent penetration is rapid and unhindered. This optimal situation no longer exists during the assembly of a difficult peptide, where the normally accessible solid phase reaction matrix becomes partially inaccessible during assembly. This situation arises suddenly, typically 6-12 residues into the synthesis, and may then persist for a number of cycles before easing, or in extreme cases remain throughout the completion of the assembly. The crude products are particularly poor if slower coupling β-branched residues (isoleucine, valine, threonine) are introduced after the onset of synthetic difficulties. The principles underlying the occurrence of difficult peptide sequences have for many years been the focus of intense debate and research. An intrinsic feature of the numerous ideas proposed is that aggregation occurs resulting in poor solvation within the peptide-polymer matrix.
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Biswas, Ranjit. "Introducing “NR-Statistics”." In Handbook of Research on Generalized and Hybrid Set Structures and Applications for Soft Computing, 490–535. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9798-0.ch023.
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The existing volume of literature on the classical subject STATISTICS is renamed by a new nomenclature called by “R-Statistics”. The chapter then introduces a new dimension in the subject STATISTICS called by “NR-Statistics”. The subject STATISTICS is then reshaped as the union of the two topics: “R-Statistics” and “NR-Statistics”. The “NR-Statistics” has grown (and will grow in future) mainly on the basis of soft-computing techniques using Generalized & Hybrid Set like Structures viz. Fuzzy Set, Intuitionistic Fuzzy Set, Bag, Multiset, Solid Matrix, Solid Latrix, Solid Hematrix, Solid Helatrix etc. In the subject STATISTICS in its newly proposed shape, populations are divided into two categories: R-Population and NR-Population. If a population consists of real number data (n-dimensional) only then it is of category ‘R-Population', and if a population does not fall into the category of ‘R-Population' then it is of the category ‘NR-Population'. Thus NR-Population may contain R-population too. The “Theory of NR-Statistics” is a new direction in Statistics which in fact other half of the subject unearthed now for rigorous study and research. The ‘Big Data Statistics' is a new era where the population (R or NR) consist of big data.
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Henderson, Peter A. "Age-Grouping, Time-Specific Life-Tables, and Predictive Population Models." In Southwood's Ecological Methods, 362–83. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198862277.003.0012.
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This chapter describes techniques to create life-tables for animals whose generations overlap widely. Age-grouping is a prerequisite for these methods, which have been most widely applied to vertebrate populations. Age cannot be inferred from the developmental stage without reference to the environment. The speed of development may be temperature-dependent or influenced by factors such as oxygen and food availability. The methods for ageing animal groups, including invertebrates, fish, reptiles, amphibians, birds, and mammals, are reviewed. Time-specific life-tables, population modelling, and Leslie matrices are described. R code to analyze Leslie matrix dynamics is presented.
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Trappey, A. J. C., Andy Z. C. Huang, Neil K. T. Chen, Regan J. S. Pa, C. V. Trappey, K. A. Li, and L. P. Hung. "Transdisciplinary Technology Mining of Advanced 6G Satellite Communication Innovations." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220688.
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This research focuses on using natural language processing text mining approaches to make knowledge induction from the patent corpus within 6G satellite communication technologies. The domain ontology, that describes the transdisciplinary features of the knowledge taxonomy, is derived and organized in a hierarchical schema. The trends of innovation distributions within the ontology are further analyzed to discover the transdisciplinary R&D requirements. The technology mining process discovers that the advanced satellite infrastructure and its hardware/software integration are the enabler for seamless and high-speed communication network connectivity on land, sea, and sky. Seven main parts of “6G satellite communication” ontology schema and the taxonomy are text-mined from relevant patents and literature. 2357 domain patents (all with highly transdisciplinary nature) are collected and analyzed. During macro-analyses, trend of inventions, the leading assignees, and the distribution of technology categories are depicted. The micro-analyses discover the innovations of technological themes, technology function matrix showing R&D hot-spots and cold-spots, and the most critical sub-technologys’ lifecycle maturities. The ultra-goal of this research is to discover the main trends and the potentials of satellite communication-related technologies through smart technology mining techniques, especially those requiring transdisciplinary R&D. Finally, the strategic research plan for technical-savvy countries (e.g., Taiwan focusing on semiconductor and IT design and manufacturing sectors) is presented, highlighting the necessary transdisciplinary R&D efforts for mobile telecommunication industry.
Conference papers on the topic "R-matrix technique"
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Kirkland, W. Grant, and S. C. Sinha. "Symbolic Computation of Quantities Associated With Time-Periodic Dynamical Systems." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-47486.
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Many dynamical systems can be modeled by a set of linear/nonlinear ordinary differential equations with periodic time-varying coefficients. The state transition matrix Φ(t,α) associated with the linear part of the equation can be expressed in terms of the periodic Lyapunov-Floquét transformation matrix Q(t,α) and a time-invariant matrix R(α). Computation of Q(t,α) and R(α) in a symbolic form as a function of system parameters α is of paramount importance in stability, bifurcation analysis, and control system design. In the past, a methodology has been presented for computing Φ(t,α) in a symbolic form, however Q(t,α) and R(α) have never been calculated in a symbolic form. Since Q(t,α) and R(α) were available only in numerical forms, general results for parameter unfolding and control system design could not be obtained in the entire parameter space. In this work a technique for symbolic computation of Q(t,α), and R(α) matrices is presented. First, Φ(t,α) is computed symbolically using the shifted Chebyshev polynomials and Picard iteration method as suggested in the literature. Then R(α) is computed using the Gaussian quadrature integral formula. Finally Q(t,α) is computed using the matrix exponential summation method. Using Mathematica, this approach has successfully been applied to the well-known Mathieu equation and a four dimensional time-periodic system in order to demonstrate the applications of the proposed method to linear as well as nonlinear problems.
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Bouquet, Pascal J. P., and Albert H. Cardon. "Application of the Electronic Speckle Pattern Interferometry (ESPI) Technique for the Localisation Analysis of Damage Development in Composites." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33448.
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The analysis of the long-term behaviour of polymer matrix composites has to be performed for their stiffness evolution and for their strength changes. Long fiber reinforced polymer matrix composites exhibit an anisotropic viscoelastic-viscoplastic behaviour. The non-linear viscoelastic constitutive equations proposed by R. Schapery [1], with a viscoplastic correction are able to analyse the long-term stiffness evolution on the basis of some short-term creep and creep-recovery tests. For the strength analysis it is possible to consider some delayed failure approach as the end of a viscoelastic-viscoplastic behaviour. The experimental follow-up of the creep evolution till rupture needs a full field technique in order to have a complete view of the strain field and the evolution of this field where the damage initiation and development transforms the homogeneous strain distribution in an heterogeneous one. The ESPI technique shows clearly the location of the damage initiation and allows us to follow the damage development. Examples of the ESPI technique on graphite epoxy specimen will be presented and the results in relation to the delayed failure analysis will be discussed.
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Heroux-Vaillancourt, Mikael, and Catherine Beaudry. "Validation of innovation indicators from companies’ websites." In CARMA 2018 - 2nd International Conference on Advanced Research Methods and Analytics. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/carma2018.2018.8333.
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In this exploratory study, we use a web mining technique to source data in order to create innovation indicators of Canadian nanotechnology and advanced materials firms. 79 websites were extracted and analysed based on keywords related to the concepts of R&D and intellectual property. To understand what our web mining indicators actually measure, we compare them with those from a classic questionnaire-based survey. Formative indices from the surveys variables were built to better represent all the possibilities resulting from the web mining indicators. A MTMM matrix lead us to conclude that the formative indices are a good representation of the web mining indicators. As a consequence, the data extracted via our web mining technique can be used as proxies for the relative importance of R&D and the importance of IP, which would have previously only been measured using conventional methods such as government administrative data or questionnaire-based surveys.
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Fischer, F. F., M. D. Dvorak, and S. Siegmann. "Development of Ultra Thin Carbide Coatings for Wear and Corrosion Resistance." In ITSC2001, edited by Christopher C. Berndt, Khiam A. Khor, and Erich F. Lugscheider. ASM International, 2001. http://dx.doi.org/10.31399/asm.cp.itsc2001p1131.
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Abstract The increasing demand of the industry for high quality coatings with a low cost aspect has led to the development of ultra thin, nearby finishing free carbide coatings. The R&D work performed for this publication was focused on the tailoring of carbide powders together with the development of a new generation of HVOF-Systems working on higher combustion chamber pressures. An as-sprayed surface roughness of less than 1,5µm has to be envisaged for a thin nearly finishing free coating. Therefore, the starting powder has to have fine particles size with a homogenous distribution of carbides and matrix metals. To ensure the corrosion resistance, the matrix metals have to be completely alloyed and the coatings have to be dense. The used HVOF-System must be able to feed and spray these fine powders without any blockage of the powder feeder or nozzle clocking. The coating quality has to fulfil the requirements of hardchrome plating as wear and corrosion resistance is concerned. The low cost level of thin hard-chrome coatings shall be matched. The suitability for using this coating on applications like hydraulic cylinders has been proven. Generally, this technique of thermal spraying can be used as a hard-chrome alternative as well as for new applications where thermal spraying was not put into account due to cost and technical reasons. The aim was to fill the gap between thin film technologies as PVD or CVD techniques and conventional thermal spraying. The new technology enables the industry to coat large components with nearly no restrictions in size and for competitive prices.
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Greene, Chris H. "Multiple Excitation of Atomic Electrons." In Multiple Excitations of Atoms. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/mea.1986.tua1.
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The strong interactions between simultaneously-excited electrons require nonperturbati ve theoretical techniques for their successful description. Two such nonperturbative techniques which have been pursued vigorously in recent years are the adiabatic treatment in hyperspherical coordinates and the R-matrix method. Of these, the hyperspherical treatment, which singles out the total electronic moment of inertia as an adiabatic coordinate, has been more valuable in providing a visual picture of the global evolution of electron correlations in energy and radius. The R-matrix method has evolved instead into a simple, efficient, and accurate procedure for quantitative calculations of photoionization and scattering processes. To date, however, the applications of this finite-volume variational method have been restricted primarily to the lower-lying doubly-excited channels of any given atom or molecule.
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Sarzosa, Diego F. B., R. Savioli, C. Ruggieri, and Alexandre Galiani Garmbis. "Comparison of Fracture Toughness Curves Obtained by Single and Multi-Specimen Methodologies for a Pipe Having an Undermatched Girth Weld." In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21546.
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Abstract Preventing catastrophic failure of engineering components is critical during the exploration and production of oil and gas resources from the offshore deep-water fields in Brazil. Pre-salt reserves are associated with high concentration of aggregated elements to hydrocarbons, particularly carbon dioxide (CO2) and hydrogen sulfide (H2S) which, in the presence of water can produce highly corrosive elements. One solution to this problem is to apply a metal liner made of corrosion-resistant alloy (CRA) internally to the carbon steel pipe. Such a bi-metallic configuration, commonly referred to as a lined pipe or clad pipe, consists essentially of a relatively thin CRA material pipe physically or metallurgically joined to the main carbon steel outer pipe. This experimental study presents an investigation of the ductile tearing properties for the girth weld of a typical C-Mn pipe internally clad with Inconel 625 CRA alloy using experimentally measured crack growth resistance curves. Here, the material of the external pipe is an API 5L Grade X65 pipeline steel and the inner clad layer is made of Inconel nickel-chromium alloy 625 (UNS N06625). The higher mechanical strength and superior resistance to a wide range of corrosive environments of unusual severity for this material derived from the combination of the nickel-chromium matrix with other microalloying elements. Testing of the pipeline girth welds employed clamped SE(T) specimens with a weld centerline notch to determine the crack growth resistance curves based upon the unloading compliance (UC) method using a single specimen method and the multi-specimen technique. The SE(T) specimens were extracted from a clad pipe having an external diameter of 220 mm and thickness of 23 mm. Further, the current experimental characterization provides toughness data that serve to evaluate the effectiveness of current procedures in determining accurate experimentally measured R-curves for this class of material.
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Warren, Russell E. "An Adaptive Kalman-Bucy Filter for Differential Absorption Lidar Time Series Data." In Laser and Optical Remote Sensing: Instrumentation and Techniques. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/lors.1987.mc6.
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An earlier work1 described a generalization of two-wavelength differential absorption lidar to the case of multiple wavelength channel returns for estimating the path-integrated concentration (CL) for multiple materials. A maximum likelihood (ML) estimator was constructed for the N-dimensional vector CL = [CL1,…,CLN]T of path-integrated concentration values in terms of lidar returns pi(k) collected simultaneously at i = 1,…1, M ≥ N+1 wavelengths at time step k. Those returns were used to define an observation vector s(k), Eq. (1), which could be expressed approximately as Eq. (2) in terms of the M-1 × N-dimensional matrix of absorptivity differences R i l = ρ 1 l − ρ 1 + 1 l of material ℓ at wavelength i. The measurement noise ns(k) was taken to be additive, uncorrelated, and zero-mean with covariance Λs (k,k′) = <n nT >δkk′. The ML estimator for CL was shown to be given by Eq. (3) in terms of the ML estimate for the CL covariance Λ CL ML , Eq. (4).
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Priess, M. Cody, Jongeun Choi, and Clark Radcliffe. "The Inverse Problem of Continuous-Time Linear Quadratic Gaussian Control With Application to Biological Systems Analysis." In ASME 2014 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/dscc2014-6100.
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In this paper, we demonstrate two methods for solving the inverse problem of continuous-time LQG control. This problem can be defined as: given a known LTI system with feedback controller K and Kalman gain L, can we find the weighting matrices Q, R (for state and input, respectively) and estimated noise intensities W, V (for process and measurement noise, respectively) such that the LQG control synthesis problem using these weights generates K and L? We formulate a regularized version of this problem as a minimization problem subject to a set of Linear Matrix Inequalities (LMIs). If feasible, a unique exact solution to the inverse LQR problem exists. If the LMIs are infeasible, we show a gradient descent algorithm that will find Q, R, W, and V to minimize the error in the recovered gain matrices K and L. We demonstrate these techniques through several numerical examples and formulate a human postural control case study to which we intend to apply our proposed techniques.
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Das, S. K., S. Utku, G. S. Chen, and B. K. Wada. "Optimal Placement of Actuators in the Precision Control of Truss Structures." In ASME 1991 Design Technical Conferences. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/detc1991-0189.
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Abstract Actuator placement criteria in truss structures are based on satisfying two goals: (1) precision control (displacement control) of precision points, and, (2) prestressing control (i.e., creation of initial stresses) to counteract joint looseness. It is shown that stress-free exact displacement control is possible in (a) statically determinate trusses using as many actuators (q) as the number of independent degrees of freedom at precision points (p), i.e., q = p; (b) in statically indeterminate trusses using q = p + r actuators, where r is the degree of redundancy. Using (a) q < p actuators in statically determinate trusses will allow only for approximate displacement control, and, (b) using q < p+r actuators, in statically indeterminate trusses, will allow for: (1) exact, stress-induced displacement control if q > p, with q-p actuators to relieve stress as best as possible; (2) approximate, stress-free displacement control if p > q > r, or, (3) approximate, stress-induced displacement control if q < p and q < r. For prestressing control using actuators, the structure must be indeterminate at least to degree 1. If indeterminate to degree r, it is either possible to (a) exactly control a maximum of r components of member forces (using q = r actuators), or, (b) exactly control all member forces, provided they lie in the column space of the null matrix of the coefficient matrix of bar forces in the force equilibrium equations of the joints (using q = r actuators). By using q < r actuators, it is possible to exactly control only q components of member forces. It is also shown that, with sufficient number of actuators, prestressing control with no disturbance to precision points is possible. Optimal actuator placement schemes are studied for some of the above cases of precision control and prestressing control, based on objectives which are specific to each case. In statically indeterminate truss structures the optimal placement criteria and techniques differ depending on whether the primary determinate structure is known or not. A suboptimal actuator placement solution to the global optimization problem, combining the objectives of displacement control and prestressing control, is suggested (for the case q < p and q < r) by combining the results of the separate optimization problems (displacement control, prestressing control); the suboptimal solution is improved (with respect to global optimum) by iteration.
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Sendrea, Claudiu, Maria-Cristina Micu, Emanuel Hadimbu, Simona Maria Paunescu, Iulia Maria Caniola, Madalina Ignat, Lucretia Miu, and Elena Badea. "Micro DSC and NMR MOUSE studies of collagen–vegetable tannin interaction mechanism during leather making." In The 8th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2020. http://dx.doi.org/10.24264/icams-2020.v.13.
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In this study NMR MOUSE and micro DSC techniques were used to investigate the interaction between collagen and various vegetable tannins during leather making process with the aim of gaining a deeper understanding of different water environment in relation to tannin type. We have previously showed that relaxation times may provide useful information on collagen matrix properties. The vegetable tanned leathers were obtained by patented techniques inspired from ancient recipes at the National R&D Institute for Textile and Leather, ICPI Division, Bucharest using various vegetable extracts such as myrobalan, gambier and chestnut. Longitudinal and transversal relaxation times T1 and T2eff were measured using a PM2 portable NMR-MOUSE with 20.05 MHz frequency. Micro DSC measurements were carried out with a high-sensitivity SETARAM Micro-DSC III in the temperature range (5 to 95) °C at 0.5 K min-1 heating rate. The investigated leathers showed significant differences in the values of spin-spin (T2eff) and spin-lattice (T1) relaxation times depending on tannin type that well corelates with the variation of the calorimetric parameters (denaturation temperature and enthalpy, peak shape). These results highlight the complementarity of the information obtained by the two techniques and open new ways for both designing new leather assortments and analyses of historical and archaeological leather.
Reports on the topic "R-matrix technique"
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Naim, Michael, Gary R. Takeoka, Haim D. Rabinowitch, and Ron G. Buttery. Identification of Impact Aroma Compounds in Tomato: Implications to New Hybrids with Improved Acceptance through Sensory, Chemical, Breeding and Agrotechnical Techniques. United States Department of Agriculture, October 2002. http://dx.doi.org/10.32747/2002.7585204.bard.
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The tomato, a profitable vegetable crop in both the USA and Israel, has benefited significantly from intensive breeding efforts in both countries, and elsewhere (esp. Holland). : Modem hybrids are highly prolific and resistant to a variety of major pests. They produce attractive, firm fruit for both processing and fresh-marketing. In all cases, however, reduction in flavor and aroma have occurred concomitantly with the increase in yield. Sugars-acids ratio dominate fruit taste, whereas aroma volatiles (potent at minute ppb and ppt levels) contribute to the total characteristic tomato flavor. An increase in sugars (1-2%) contributes significantly to tomato fruit taste. However, because of energy reasons, an increase in fruit sugars is immediately compensated for by a decrease in yield. Our main objectives were to: (a) pinpoint and identify the major impact aroma components of fresh tomato; (b) study the genetic and environmental effects on fruit aroma; (c) determine precursors of appealing (flavors) and repelling (off-flavors) aroma compounds in tomato. Addition of saturated salts blocked all enzymatic activities prior to isolation of volatiles by dynamic and static headspace, using solvent assisted flavor evaporation (SAFE) and solid phase micro-extraction (SPME) from highly favored (FA-612 and FA-624) and less preferred (R 144 and R 175) tomato genotypes. Impact aroma components were determined by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC- MS) and aroma extract dilution analysis (AEDA). The potent odorant (Z)-1,5-octadien-3-one, was identified for the first time in fresh tomato. From the ca. 400 volatile compounds in the headspace of fresh tomato, the following compounds are proposed to be impact aroma compounds: (Z)-3-hexenal, hexanal, 1-penten-3-one, 2-phenylethanol, (E)-2-hexenal, phenyl acetaldehyde, b-ionone, b-damascenone, 4-hydroxy-2,5-dimethyl-3-(2H)-furanone (FuraneolR), (Z)-l,5-octadien-3-one, methional, 1-octen-3-one, guaiacol, (E,E)- and (E,Z)- 2,4-decadienal and trans- and cis-4,5-EPOXY -(E)-2-decenal. This confirms the initial hypothesis that only a small number of volatiles actually contribute to the sensation of fruit aroma. Tomato matrix significantly affected the volatility of certain impact aroma components and thus led to the conclusion that direct analysis of molecules in the headspace . may best represent access of tomato volatiles to the olfactory receptors. Significant differences in certain odorants were found between preferred and less-preferred cultivars. Higher consumer preference was correlated with higher concentrations of the following odorants: l-penten-3-one, (Z)-3-hexenal, (E,E)- and (E,Z)-2,4-decadienal and especially Furaneol, whereas lower consumer preference was associated with higher concentrations of methional, 3-methylbutyric acid, phenylacetaldehyde, 2-phenylethanol, and 2-isobutylthiazole. Among environmental factors (salinity, N source, growth temperature), temperature had significant effects on the content of selected aroma compounds (e.g., 3-methylbutanal, 1- penten-3-one, hexanal, (Z)-3-hexenal, (E)-2-hexenal, 2-isobutylthiazole, 6-methyl-5-hepten- 2-one, 1-octen-3-one, methional, 2-phenylethanal, phenyl acetaldehyde, and eugenol) in fresh tomatoes. Salt stress (20 mM NaCl) increased the content of odorants such as (Z)-3-hexenal, 2-phenylethanol and 3-methylbutanal in the R-144 cultivar whereas salinity had minor effects on 1-pentene-3-one, 2-isobutylthiazole and b-ionone. This fundamental knowledge obtained by comprehensive investigation, using modem chemical, sensory and agrotechnical methodology will assist future attempts to genetically modify the concentrations of key odorants in fresh tomatoes, and thus keep the tomato production of Israel and the USA competitive on the world market.