Energy Technology Data Exchange (ETDEWEB)
Tsuchiya, K. [Department of Production Systems Engineering, Toyohashi University of Technology (Japan)]. E-mail: tsuchiya@pse.tut.ac.jp; Inuzuka, M. [Department of Production Systems Engineering, Toyohashi University of Technology (Japan); Tomus, D. [Department of Production Systems Engineering, Toyohashi University of Technology (Japan); Hosokawa, A. [Department of Production Systems Engineering, Toyohashi University of Technology (Japan); Nakayama, H. [Department of Mechanical Engineering, University of Washington (United States); Morii, K. [Research and Development Laboratory, Daido Steel, Co., Ltd. (Japan); Todaka, Y. [Department of Production Systems Engineering, Toyohashi University of Technology (Japan); Umemoto, M. [Department of Production Systems Engineering, Toyohashi University of Technology (Japan)
2006-11-25
Martensitic transformation and mechanical behavior was investigated on TiNi shape memory alloy subjected to severe plastic deformation by cold rolling. Transmission electron microscopy revealed the sample to be a mixture of nanocrystalline and amorphous material after 40% cold rolling. Diffrential scaning calorimetry measurements and X-ray diffractometry suggested that the martensitic transformation was suppressed when the thickness reduction was over 25%. The pseudoelastic stress-strain curves of nanocrystalline/amorphous TiNi are characterized by the absence of a stress-plateau and by small hysteresis.
DEFF Research Database (Denmark)
Hansen, Morten Tranberg; Kusy, Branislav
environment for WSN applications that aims to resolve both of these problems. It provides drag-and-drop visual programming language Open Blocks that is easy to use for novice programmers. TinyInventor also unifies development of mote and PC code by using cross-platform programming abstractions, namely thread...... based execution models and IPv6 communication primitives. We demonstrate through an application example that TinyInventor is both simple to use and powerful in expressing complex applications....
DEFF Research Database (Denmark)
Bonnet, Philippe; Culler, David; Estrin, Deborah
2006-01-01
This memo describes the goals and organization structure of the TinyOS Alliance. It covers membership, the working group forums for contribution, intellectual property, source licensing, and the TinyOS Steering Committee (TSC).......This memo describes the goals and organization structure of the TinyOS Alliance. It covers membership, the working group forums for contribution, intellectual property, source licensing, and the TinyOS Steering Committee (TSC)....
Böttcher, J.; Jahn, M.; Tatzko, S.
2017-12-01
Pseudoelastic shape memory alloys exhibit a stress-induced phase transformation which leads to high strains during deformation of the material. The stress–strain characteristic during this thermomechanical process is hysteretic and results in the conversion of mechanical energy into thermal energy. This energy conversion allows for the use of shape memory alloys in vibration reduction. For the application of shape memory alloys as vibration damping devices a dynamic modeling of the material behavior is necessary. In this context experimentally determined material parameters which accurately represent the material behavior are essential for a reliable material model. Subject of this publication is the declaration of suitable material parameters for pseudoelastic shape memory alloys and the methodology of their identification from experimental investigations. The used test rig was specifically designed for the characterization of pseudoelastic shape memory alloys.
DEFF Research Database (Denmark)
Enemark, Søren; Santos, Ilmar; Savi, M. A.
2016-01-01
The thermo-mechanical behaviour of pseudoelastic shape memory alloy helical springs is of concern discussing stabilised and cyclic responses. Constitutive description of the shape memory alloy is based on the framework developed by Lagoudas and co-workers incorporating two modifications related...
An experimental study on pseudoelasticity of a NiTi-based damper for civil applications
Nespoli, Adelaide; Bassani, Enrico; Della Torre, Davide; Donnini, Riccardo; Villa, Elena; Passaretti, Francesca
2017-10-01
In this work, a pseudoelastic damper composed by NiTi wires is tested at 0.5, 1 and 2 Hz for 1000 mechanical cycles. The damping performances were evaluated by three key parameters: the damping capacity, the dissipated energy per cycle and the maximum force. During testing, the temperature of the pseudoelastic elements was registered as well. Results show that the damper assures a bi-directional motion throughout the 1000 cycles together with the maintenance of the recentering. It was observed a stabilization process in the first 50 mechanical cycles, where the key parameters reach stable values; in particular it was found that the damping capacity and the dissipated energy both decrease with frequency. Besides, the mean temperature of the pseudoleastic elements reaches a stable value during tests and confirms the different response of the pseudoelastic wires accordingly with the specific length and stain. Finally, interesting thermal effects were observed at 1 and 2 Hz: at these frequencies and at high strains, the maximum force increases but the temperature of the NiTi wire decreases being in contraddiction with the Clausius-Clapeyron law.
Directory of Open Access Journals (Sweden)
Y. M. Parulekar
2012-01-01
Full Text Available Recently, there has been increasing interest in using superelastic shape memory alloys for applications in seismic resistant-design. Shape memory alloys (SMAs have a unique property by which they can recover their original shape after experiencing large strains up to 8% either by heating (shape memory effect or removing stress (pseudoelastic effect. Many simplified shape memory alloy models are suggested in the past literature for capturing the pseudoelastic response of SMAs in passive vibration control of structures. Most of these models do not consider the cyclic effects of SMA's and resulting residual martensite deformation. Therefore, a suitable constitutive model of shape memory alloy damper which represents the nonlinear hysterical dynamic system appropriately is essential. In this paper a multilinear hysteretic model incorporating residual martensite strain effect of pseudoelastic shape memory alloy damper is developed and experimentally validated using SMA wire, based damper device. A sensitivity analysis is done using the proposed model along with three other simplified SMA models. The models are implemented on a steel frame representing an SDOF system and the comparison of seismic response of structure with all the models is made in the numerical study.
Washington's Beautiful, Illegal Tiny Houses
National Research Council Canada - National Science Library
Todd Krainin
2014-01-01
Ranging in price from $10,000 to $50,000, tiny homes like The Matchbox could help to ease the shortage of affordable housing in the capital city, where the median price per square foot has climbed to a staggering $450...
New Michigan Tiny House Community Announced
National Research Council Canada - National Science Library
Michael Chamernik
2016-01-01
A new tiny house community called Tiny House Estates has been announced and will be located at the northern end of Michigan's Lower Peninsula, at Traverse Bay Resort in Traverse City, near the shores of Lake Michigan...
Finite Element Analysis of the Pseudo-elastic Behavior of Shape Memory Alloy Truss and Beam
Directory of Open Access Journals (Sweden)
Kamal M. Bajoria
2010-07-01
Full Text Available The pseudo-elastic behavior of Shape memory alloy (SMA truss and cantilever beam are investigated. Brinson’s one-dimensional material model, which uses the twinned and detwinned martensite fractions separately as internal variables, is applied in the algorithm to establish the SMA stress-strain characteristics. This material model also incorporates different young’s modulus for austenitic and martensite phase to represent the true SMA characteristics. In this model, a cosine function was used to express the evolution of the stress induced martensite fractions during the forward and reverse martensite phase transformation. A finite element formulation for the SMA truss member considering the geometric nonlinearity is proposed and the results are compared with the corresponding linear analysis. As a step forward, a finite element formulation for an SMA cantilever beam with an applied end moment is proposed. The load displacement characteristic for both the loading and unloading phases are considered to check the full pseudo-elastic hysteretic loop. In the numerical investigation, the stress-strain variation along the beam depth is also examined during the loading and unloading process to investigate the forward and reverse martensite phase transformation phenomena. Newton-Raphson’s iterative method is applied to get convergence to the equilibrium for each loading steps. During a complete loading-unloading process, the temperature is kept constant as the model is essentially an isothermal model. Numerical simulation is performed considering two different temperatures to demonstrate the effect of temperature on the hysteretic loop.
Numerical simulation of pseudoelastic shape memory alloys using the large time increment method
Gu, Xiaojun; Zhang, Weihong; Zaki, Wael; Moumni, Ziad
2017-04-01
The paper presents a numerical implementation of the large time increment (LATIN) method for the simulation of shape memory alloys (SMAs) in the pseudoelastic range. The method was initially proposed as an alternative to the conventional incremental approach for the integration of nonlinear constitutive models. It is adapted here for the simulation of pseudoelastic SMA behavior using the Zaki-Moumni model and is shown to be especially useful in situations where the phase transformation process presents little or lack of hardening. In these situations, a slight stress variation in a load increment can result in large variations of strain and local state variables, which may lead to difficulties in numerical convergence. In contrast to the conventional incremental method, the LATIN method solve the global equilibrium and local consistency conditions sequentially for the entire loading path. The achieved solution must satisfy the conditions of static and kinematic admissibility and consistency simultaneously after several iterations. 3D numerical implementation is accomplished using an implicit algorithm and is then used for finite element simulation using the software Abaqus. Computational tests demonstrate the ability of this approach to simulate SMAs presenting flat phase transformation plateaus and subjected to complex loading cases, such as the quasi-static behavior of a stent structure. Some numerical results are contrasted to those obtained using step-by-step incremental integration.
TinyPower – Power conversion on a tiny scale
DEFF Research Database (Denmark)
Han, Anpan; Jørgensen, Anders Michael
2014-01-01
The world surrounding us is filled with devices relying on electrical power and the rise of internet-of-thingswill mean that powering devices will remain important in the future. The size and cost of the power supplyhas become a dominant factor in many applications. At the same time, most...... of the power supplies havelarge electrolytic capacitators, which are expensive, bulky and often limit the product lifetime. Theambition of the TinyPower project is to develop an integrated switch-mode power supply consisting of anintegrated circuit (IC) where only a few external components need to be added...... effort is placed on assembling the integrated circuits and passive components. This will mostlikely be based on a interposer, a miniature circuit board which must account for not only the electricalsignals but also the magnetic fields, so as not too reduce conversion efficiency too much.The Tinypower...
Greiner-Petter, Christoph; Sattel, Thomas
2017-12-01
For planar tubular continuum structures based on precurved shape memory alloy tubes a beam model with respect to the pseudoelastic material behaviour of NiTi is derived. Thereunto a constitutive material law respecting tension-compression asymmetry as well as hysteresis is used. The beam model is then employed to calculate equilibrium curvatures of concentric tube assemblies without clearance between the tubes. In a second step, the influence of clearance is approximated to account for non-concentric tube assemblies. These elastokinematic results are integrated into a purely kinematic model to describe the cannula path under the presence of material hysteresis and clearance. Finally a photogrammetric measurement system is used to track the path of an exemplary two-tube continuum structure to examine the accuracy of the proposed model. It is shown that material hysteresis leads to a hysteresis phenomena in the path of the tubular continuum structure.
Nonlinear dynamics of a pseudoelastic shape memory alloy system - theory and experiment
DEFF Research Database (Denmark)
Enemark, Søren; A Savi, M.; Santos, Ilmar
2014-01-01
In this work, a helical spring made from a pseudoelastic shape memory alloy was embedded in a dynamic system also composed of a mass, a linear spring and an excitation system. The mechanical behaviour of shape memory alloys is highly complex, involving hysteresis, which leads to damping...... capabilities and varying stiffness. Besides, these properties depend on the temperature and pretension conditions. Because of these capabilities, shape memory alloys are interesting in relation to engineering design of dynamic systems. A theoretical model based on a modification of the 1D Brinson model...... was established. Basically, the hardening and the sub-loop behaviour were altered. The model parameters were extracted from force–displacement tests of the spring at different constant temperatures as well as from differential scanning calorimetry. Model predictions were compared with experimental results of free...
Transformation-induced plasticity during pseudoelastic deformation in Ni-Ti microcrystals
Energy Technology Data Exchange (ETDEWEB)
Norfleet, D.M. [Engineering Systems Inc., 3851 Exchange Ave., Aurora, IL 60504 (United States); Sarosi, P.M. [General Motors, R and D Tech Center, 30500 Mound Road, Warren, MI 48090 (United States); Manchiraju, S. [Department of Materials Science and Engineering, Ohio State University, 2041 College Road, Columbus, OH 43201 (United States); Wagner, M.F.-X. [Lehrstuhl Werkstoffwissenschaft, Institut fuer Werkstoffe, Ruhr-Universitaet Bochum, Universitaetsstr. 150, D-44801 Bochum (Germany); Uchic, M.D. [Air Force Research Labs RXLM, Wright-Patterson AFB, OH 45433 (United States); Anderson, P.M. [Department of Materials Science and Engineering, Ohio State University, 2041 College Road, Columbus, OH 43201 (United States); Mills, M.J., E-mail: mills.108@osu.edu [Department of Materials Science and Engineering, Ohio State University, 2041 College Road, Columbus, OH 43201 (United States)
2009-07-15
[1 1 0]-oriented microcrystals of solutionized 50.7 at.% Ni-Ti were prepared by focused ion beam machining and then tested in compression to investigate the stress-induced B2-to-B19' transformation in the pseudoelastic regime. The compression results indicate a sharp onset of the transformation, consistent with little prior plasticity. Post-mortem scanning transmission electron microscopy reveals no apparent retained martensite but rather a macroscopic band of dislocation activity within which are planar arrays of {approx}100 nm dislocation loops involving a single a<0 1 0>{l_brace}1 0 1{r_brace} slip system. Micromechanics analyses show that the angle of the band is consistent with activation of a favored martensite plate. Further, the stress from the individual variants within the plate is shown to favor activation of the observed slip system. The work done by the applied stress during the B2-to-B19' transformation is estimated to be {approx}34 MJ m{sup -3} at ambient temperature.
Nano-hardness, wear resistance and pseudoelasticity of hafnium implanted NiTi shape memory alloy.
Zhao, Tingting; Li, Yan; Liu, Yong; Zhao, Xinqing
2012-09-01
NiTi shape memory alloy was modified by Hf ion implantation to improve its wear resistance and surface integrity against deformation. The Auger electron spectroscopy and x-ray photoelectron spectroscopy results indicated that the oxide thickness of NiTi alloy was increased by the formation of TiO₂/HfO₂ nanofilm on the surface. The nano-hardness measured by nano-indentation was decreased even at the depth larger than the maximum reach of the implanted Hf ion. The lower coefficient of friction with much longer fretting time indicated the remarkable improvement of wear resistance of Hf implanted NiTi, especially for the sample with a moderate incident dose. The formation of TiO₂/HfO₂ nanofilm with larger thickness and decrease of the nano-hardness played important roles in the improvement of wear resistance. Moreover, Hf implanted NiTi exhibited larger pseudoelastic recovery strain and retained better surface integrity even after being strained to 10% as demonstrated by in situ scanning electron microscope observation. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.
How Tiny Collisions Shape Mercury
Kohler, Susanna
2017-07-01
If space rocks are unpleasant to encounter, space dust isnt much better. Mercurys cratered surface tells of billions of years of meteoroid impacts but its thin atmosphere is what reveals its collisional history with smaller impactors. Now new research is providing a better understanding of what were seeing.Micrometeoroids Ho!The inner solar system is bombarded by micrometeoroids, tiny particles of dust (on the scale of a tenth of a millimeter) emitted by asteroids and comets as they make their closest approach to the Sun. This dust doesnt penetrateEarths layers of atmosphere, but the innermost planet of our solar system, Mercury, doesnt have this convenient cushioning.Just as Mercury is affected by the impacts of large meteoroids, its also shaped by the many smaller-scale impacts it experiences. These tiny collisions are thought to vaporize atoms and molecules from the planets surface, which quickly dissociate. This process adds metals to Mercurys exosphere, the planets extremely tenuous atmosphere.Modeling PopulationsDistribution of the directions from which meteoroids originate before impacting Mercurys surface, as averaged over its entire orbit. Local time of 12 hr corresponds to the Sun-facing side. A significant asymmetry is seen between the dawn (6 hrs) and dusk (18 hrs) rates. [Pokorn et al. 2017]The metal distribution in the exosphere provides a way for us to measure the effect of micrometeoroid impacts on Mercury but this only works if we have accurate models of the process. A team of scientists led by Petr Pokorn (The Catholic University of America and NASA Goddard SFC) has now worked to improve our picture of micrometeoroid impact vaporization on Mercury.Pokorn and collaborators argue that two meteoroid populations Jupiter-family comets (short-period) and Halley-type comets (long-period) contribute the dust for the majority of micrometeoroid impacts on Mercury. The authors model the dynamics and evolution of these two populations, reproducing the
Physicists tackles questions of tiny dimensions
Moran, Barbara
2003-01-01
Today's physicists have a dilemna: they are using two separate theories to describe the universe. General relativity, which describes gravity, works for large objects like planets. Quantum mechanics, which involves the other forces, works for tiny objects like atoms. Unfortunately, the two theories don't match up.
The Tiny Terminators-Mosquitoes and Diseases
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 5. The Tiny Terminators - Mosquitoes and Diseases. P K Sumodan. General Article Volume 6 Issue 5 May 2001 pp 48-55 ... Author Affiliations. P K Sumodan1. District Medical Office of Health Mananthavady, Wayanad Kerala 670 645, India.
Enhanced Sintering of TiNi Shape Memory Foams under Mg Vapor Atmosphere
Aydoğmuş, Tarik; Bor, Şakir
2012-12-01
TiNi alloy foams are promising candidates for biomaterials to be used as artificial orthopedic implant materials for bone replacement applications in biomedical sector. However, certain problems exist in their processing routes, such as formation of unwanted secondary intermetallic phases leading to brittleness and deterioration of shape memory and superelasticity characteristics; and the contamination during processing resulting in oxides and carbonitrides which affect mechanical properties negatively. Moreover, the eutectic reaction present in Ti-Ni binary system at 1391 K (1118 °C) prevents employment of higher sintering temperatures (and higher mechanical properties) even when equiatomic prealloyed powders are used because of Ni enrichment of TiNi matrix as a result of oxidation. It is essential to prevent oxidation of TiNi powders during processing for high-temperature (>1391 K i.e., 1118 °C) sintering practices. In the current study, magnesium powders were used as space holder material to produce TiNi foams with the porosities in the range of 40 to 65 pct. It has been found that magnesium prevents secondary phase formation and contamination. It also prevents liquid phase formation while enabling employment of higher sintering temperatures by two-step sintering processing: holding the sample at 1373 K (1100 °C) for 30 minutes, and subsequently sintering at temperatures higher than the eutectic temperature, 1391 K (1118 °C). By this procedure, magnesium may allow sintering up to temperatures close to the melting point of TiNi. TiNi foams produced with porosities in the range of 40 to 55 pct were found to be acceptable as implant materials in the light of their favorable mechanical properties.
From tiny microalgae to huge biorefineries
Gouveia, L.
2014-01-01
Microalgae are an emerging research field due to their high potential as a source of several biofuels in addition to the fact that they have a high-nutritional value and contain compounds that have health benefits. They are also highly used for water stream bioremediation and carbon dioxide mitigation. Therefore, the tiny microalgae could lead to a huge source of compounds and products, giving a good example of a real biorefinery approach. This work shows and presents examples of experimental...
Kwon, Seong-Cheol; Jeon, Su-Hyeon; Oh, Hyun-Ung
2016-05-01
A stepper-actuated mechanism, such as a gimbal type antenna, is a major source of micro-jitters that affect the image quality of a high-resolution observation satellite. Attenuating micro-jitter disturbances induced by a stepper motor activation is one method of enhancing image quality of an observation satellite. In this study, we propose a novel gear with micro-jitter attenuation capability for stepper-actuated mechanism. This can be achieved by implementing a pseudoelastic shape memory alloy mesh washer on the gear wheel. This application makes it possible to achieve the gear with lower torsional stiffness and higher damping in the torsional direction of the gear, whose characteristics will assist in resolving the micro-jitter attenuation issues of a gear. The effectiveness of the gear proposed in this study was demonstrated by numerical simulation and jitter measurement tests using the gimbal type antenna mechanism actuated by the stepper motor.
Leros: A Tiny Microcontroller for FPGAs
DEFF Research Database (Denmark)
Schoeberl, Martin
2011-01-01
Leros is a tiny microcontroller that is optimized for current low-cost FPGAs. Leros is designed with a balanced logic to on-chip memory relation. The design goal is a microcontroller that can be clocked in about half of the speed a pipelined on-chip memory and consuming less than 300 logic cells...... functions in an FPGA based system-on-chip design. Second, the very small size of Leros makes it an attractive soft core for many-core research with low-cost FPGAs....
Directory of Open Access Journals (Sweden)
Malher A.
2014-01-01
Full Text Available A passive control of aeroelastic instabilities on a two-degrees-of-freedom (dofs system is considered here using shape memory alloys (SMA springs in their pseudo-elastic regime. SMA present a solid-solid phase change that allow them to face strong deformations (∼ 10%; in the pseudo-elastic regime, an hysteresis loop appears in the stress-strain relationship which in turn gives rise to an important amount of dissipated energy. This property makes the SMA a natural candidate for damping undesired vibrations in a passive manner. A 2-dofs system is here used to model the classical flutter instability of a wing section in an uniform flow. The SMA spring is selected on the pitch mode in order to dissipate energy of the predominant motion. A simple model for the SMA hysteresis loop is introduced, allowing for a quantitative study of the important parameters to optimize in view of an experimental design.
Structural analysis of an off-grid tiny house
Calluari, Karina Arias; Alonso-Marroquín, Fernando
2017-06-01
The off-grid technologies and tiny house movement have experimented an unprecedented growth in recent years. Putting both sides together, we are trying to achieve an economic and environmental friendly solution to the higher cost of residential properties. This solution is the construction of off-grid tiny houses. This article presents a design for a small modular off-grid house made by pine timber. A numerical analysis of the proposed tiny house was performed to ensure its structural stability. The results were compared with the suggested serviceability limit state criteria, which are contended in the Australia Guidelines Standards making this design reliable for construction.
Forman, Jason L; de Dios, Eduardo del Pozo; Kent, Richard W
2010-12-01
Injury-predictive finite element (FE) models of the chest must reproduce the structural coupling behavior of the costal cartilage accurately. Gross heterogeneities (the perichondrium and calcifications) may cause models developed based on local material properties to erroneously predict the structural behavior of cartilage segments. This study sought to determine the pseudo-elastic effective material properties required to reproduce the structural behavior of the costal cartilage under loading similar to what might occur in a frontal automobile collision. Twenty-eight segments of cadaveric costal cartilage were subjected to cantilever-like, dynamic loading. Three limited-mesh FE models were then developed for each specimen, having element sizes of 10 mm (typical of current whole-body FE models), 3 mm, and 2 mm. The cartilage was represented as a homogeneous, isotropic, linear elastic material. The elastic moduli of the cartilage models were optimized to fit the anterior-posterior (x-axis) force versus displacement responses observed in the experiments. For a subset of specimens, additional model validation tests were performed under a second boundary condition. The pseudo-elastic effective moduli ranged from 4.8 to 49 MPa, with an average and standard deviation of 22 ± 13.6 MPa. The models were limited in their ability to reproduce the lateral (y-axis) force responses observed in the experiments. The prediction of the x-axis and y-axis forces in the second boundary condition varied. Neither the effective moduli nor the model fit were significantly affected (Student's t-test, p representation of the costal cartilage in whole-body FE models where these heterogeneities cannot be modeled distinctly.
Machine Code Verification of a Tiny ARM Hypervisor
Dam, Mads; Guanciale, Roberto; Nemati, Hamed
2013-01-01
Hypervisors are low level execution platforms that provideisolated partitions on shared resources, allowing to design se-cure systems without using dedicated hardware devices. Akey requirement of this kind of solution is the formal verifi-cation of the software trusted computing base, preferably atthe binary level. We accomplish a detailed verification of anARMv7 tiny hypervisor, proving its correctness at the ma-chine code level. We present our verification strategy, whichmixes the usage of ...
Gráf, Tomáš
2012-01-01
The thesis presents a theoretical framework for a portfolio for the course Teorie a praxe jazykové akvizice pro uèitele angliètiny (didaktická propedeutika). This preparatory course in didactics serves as an introduction to the subject for future teachers of English in secondary schools, whom it should equip with a basic level of understanding of the general principles of learning, language acquisition and language learning. The work presents a course syllabus, and in its individual chapters ...
The science of tiny things: physics at the nanoscale
Energy Technology Data Exchange (ETDEWEB)
Copp, Stacy Marla [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-06-07
Nanoscience is the study of tiny objects that are only a billionth of a meter in size, or about 1,000 to 10,000 times smaller than a human hair. From the electronics in your smartphone to the molecular motors that are in your body’s cells, nanoscientists study and design materials that span a huge range of subjects, from physics to chemistry to biology. I will talk about some of what we do at LANL’s Center for Integrated Technologies, as well as how I first got interested in nanoscience and how I became a nanoscientist at LANL.
Attic cholesteatoma with tiny retraction of pars flaccida.
Lee, Jun Ho; Hong, Seok Min; Kim, Chang Woo; Park, Yeo Hoon; Baek, So-Hye
2015-04-01
This clinical study was performed to analyze the characteristics of attic cholesteatoma occurring behind a tiny retraction of the pars flaccida, which was classified as Tos type I or II and had an intact pars tensa of the tympanic membrane. The clinical records of patients who underwent tympanomastoidectomy for attic cholesteatoma at a tertiary care referral center (Kangdong Sacred Heart Hospital of Seoul, Korea) between March 2004 and December 2012 were retrospectively reviewed. Eleven patients (five men and six women) who underwent tympanomastoidectomy between March 2004 and December 2012 for attic cholesteatoma occurring behind a tiny attic retraction were included. The mean age of patients was 41.1 years (range 20-58 years) and the mean duration of follow-up was 29.5 months (range 13-52 months). Every patient had a unilateral cholesteatoma, and the opposite side was normal except in one patient. Hearing loss was the most common symptom, followed by earfullness and otalgia. Five patients had type I attic retraction, and six patients had type II attic retraction. No patient had definite scutum erosion. Interestingly, during regular postoperative checkup, one patient was found incidentally for the opposite ear. Six patients had a cholesteatoma sac that was separated from the pars flaccida, whereas in five patients it was in contact with the pars flaccida but was easily separated. Six patients had a limited cholesteatoma within the epitympanum, and five patients had extension beyond the epitympanum. The average air-bone gap was 24.3±10.1dB before the operation and 14.2±6.6dB after the operation. Every patient had an intact tympanic membrane without retraction pocket postoperatively. There was no recurrence of cholesteatoma during follow-up. The rate of attic cholesteatomas occurring behind a tiny retraction of the pars flaccida was 7.7% (11 of 142 patients with attic cholesteatoma). Attic retractions must be followed closely using endoscopy, microscopy, and
Swimming of a Tiny Subtropical Sea Butterfly with Coiled Shell
Murphy, David; Karakas, Ferhat; Maas, Amy
2017-11-01
Sea butterflies, also known as pteropods, include a variety of small, zooplanktonic marine snails. Thecosomatous pteropods possess a shell and swim at low Reynolds numbers by beating their wing-like parapodia in a manner reminiscent of insect flight. In fact, previous studies of the pteropod Limacina helicina have shown that pteropod swimming hydrodynamics and tiny insect flight aerodynamics are dynamically similar. Studies of L. helicina swimming have been performed in polar (0 degrees C) and temperate conditions (12 degrees C). Here we present measurements of the swimming of Heliconoides inflatus, a smaller yet morphologically similar pteropod that lives in warm Bermuda seawater (21 degrees C) with a viscosity almost half that of the polar seawater. The collected H. inflatus have shell sizes less than 1.5 mm in diameter, beat their wings at frequencies up to 11 Hz, and swim upwards in sawtooth trajectories at speeds up to approximately 25 mm/s. Using three-dimensional wing and body kinematics collected with two orthogonal high speed cameras and time-resolved, 2D flow measurements collected with a micro-PIV system, we compare the effects of smaller body size and lower water viscosity on the flow physics underlying flapping-based swimming by pteropods and flight by tiny insects.
Paranjape, Harshad Madhukar
Shape memory alloys (SMA) show two remarkable properties- pseudoelasticity and shape memory effect. These properties make them an attractive material for a variety of commercial applications. However, the mechanism of austenite to martensite phase transformation, responsible for these properties also induces plastic deformation leading to structural and functional fatigue. Micron scale experiments suggest that the plastic deformation is induced in part due to the local stress field of the fine martensite microstructure. However, the results are qualitative and the nature of transformation-plasticity interaction is dependent on factors like the width of the interfaces. This thesis presents a new modeling approach to study the interaction between martensite correspondence variant scale microstructure and plastic deformation in austenite. A phase field method based evolution law is developed for phase transformation and reorientation of martensite CVs. This is coupled with a crystal plasticity law for austenite plastic deformation. The model is formulated with finite deformation and rotations. The effect of local crystal orientation is incorporated. An explicit time integration scheme is developed and implemented in a finite element method (FEM) based framework, allowing the modeling of complex boundary conditions and arbitrary loading conditions. Two systematic studies are carried out with the model. First, the interaction between plasticity and phase transformation is studied for load-free and load-biased thermal cycling of single crystals. Key outcomes of this study are that, the residual martensite formed during thermal cycling provides nucleation sites for the phase transformation in the subsequent cycles. Further, the distribution of slip on different slip systems is determined by the martensite texture. This is a strong evidence for transformation induced plasticity. In the second study, experimentally informed simulations of NiTi micropillar compression are
The Mechanical Characterization and IN VIVO Evaluation of Porous TiNi as Graft Material
Arpak, Bertan; Araz, Kenan; Nakaş, Ipek; Bor, Şakir; Nergiz, Ibrahim
2012-09-01
To obtain TiNi foams with interconnected pores that have surface quality necessary for bone growth in addition to required mechanical performance, sintering with the space holder technique was employed in this study, which aimed to evaluate the bone healing process of TiNi graft materials. For this purpose, processed TiNi foams with three different porosities were placed into the created defects in the femur of rats. Moreover, the mechanical properties of the processed TiNi foams were conducted via monotonic compression tests in order to evaluate mechanical biocompatibility.
SCADA SYSTEM SIMULATION USING THE TINY TIGER 2 DEVELOPMENT BOARD
Directory of Open Access Journals (Sweden)
AGAPE C.P.
2015-12-01
Full Text Available This paper presents a new design for a surveillance and control system of a medium voltage cell. The accent is on the acquisition of information of the consumer’s state, the instantaneous current consumption, power and voltage apparent to the consumer. The proposed design is based on Wilke Technology development board at its basis being a Tiny-tiger 2 Multitasking Microcontroller. This computer has 2 MByte or 4 MByte Flash for programming, and 1 MByte SRAM with backup input for data. On the software’s behalf we managed to create a Delphi Interface which communicates with the serial port on the development board. The interface takes information about the consumer and its capacity to load with voltage.
Tiny videos: a large data set for nonparametric video retrieval and frame classification.
Karpenko, Alexandre; Aarabi, Parham
2011-03-01
In this paper, we present a large database of over 50,000 user-labeled videos collected from YouTube. We develop a compact representation called "tiny videos" that achieves high video compression rates while retaining the overall visual appearance of the video as it varies over time. We show that frame sampling using affinity propagation-an exemplar-based clustering algorithm-achieves the best trade-off between compression and video recall. We use this large collection of user-labeled videos in conjunction with simple data mining techniques to perform related video retrieval, as well as classification of images and video frames. The classification results achieved by tiny videos are compared with the tiny images framework [24] for a variety of recognition tasks. The tiny images data set consists of 80 million images collected from the Internet. These are the largest labeled research data sets of videos and images available to date. We show that tiny videos are better suited for classifying scenery and sports activities, while tiny images perform better at recognizing objects. Furthermore, we demonstrate that combining the tiny images and tiny videos data sets improves classification precision in a wider range of categories.
The kinetics of Cr layer coated on TiNi films for hydrogen absorption
Indian Academy of Sciences (India)
Abstract. The effect of hydrogen absorption on electrical resistance with temperature for TiNi and TiNi–Cr thin films was investigated. The TiNi thin films of thickness 800. Å were deposited at different angles under 10−5 Torr pressure by thermal evaporation on the glass substrate at room temperature. A layer of.
Marine Prasinoviruses and Their Tiny Plankton Hosts: A Review.
Weynberg, Karen D; Allen, Michael J; Wilson, William H
2017-03-15
Viruses play a crucial role in the marine environment, promoting nutrient recycling and biogeochemical cycling and driving evolutionary processes. Tiny marine phytoplankton called prasinophytes are ubiquitous and significant contributors to global primary production and biomass. A number of viruses (known as prasinoviruses) that infect these important primary producers have been isolated and characterised over the past decade. Here we review the current body of knowledge about prasinoviruses and their interactions with their algal hosts. Several genes, including those encoding for glycosyltransferases, methyltransferases and amino acid synthesis enzymes, which have never been identified in viruses of eukaryotes previously, have been detected in prasinovirus genomes. The host organisms are also intriguing; most recently, an immunity chromosome used by a prasinophyte in response to viral infection was discovered. In light of such recent, novel discoveries, we discuss why the cellular simplicity of prasinophytes makes for appealing model host organism-virus systems to facilitate focused and detailed investigations into the dynamics of marine viruses and their intimate associations with host species. We encourage the adoption of the prasinophyte Ostreococcus and its associated viruses as a model host-virus system for examination of cellular and molecular processes in the marine environment.
Tiny Ultraviolet Polarimeter for Earth Stratosphere from Space Investigation
Nevodovskyi, P. V.; Morozhenko, O. V.; Vidmachenko, A. P.; Ivakhiv, O.; Geraimchuk, M.; Zbrutskyi, O.
2015-09-01
One of the reasons for climate change (i.e., stratospheric ozone concentrations) is connected with the variations in optical thickness of aerosols in the upper sphere of the atmosphere (at altitudes over 30 km). Therefore, aerosol and gas components of the atmosphere are crucial in the study of the ultraviolet (UV) radiation passing upon the Earth. Moreover, a scrupulous study of aerosol components of the Earth atmosphere at an altitude of 30 km (i.e., stratospheric aerosol), such as the size of particles, the real part of refractive index, optical thickness and its horizontal structure, concentration of ozone or the upper border of the stratospheric ozone layer is an important task in the research of the Earth climate change. At present, the Main Astronomical Observatory of the National Academy of Sciences (NAS) of Ukraine, the National Technical University of Ukraine "KPI"and the Lviv Polytechnic National University are engaged in the development of methodologies for the study of stratospheric aerosol by means of ultraviolet polarimeter using a microsatellite. So fare, there has been created a sample of a tiny ultraviolet polarimeter (UVP) which is considered to be a basic model for carrying out space experiments regarding the impact of the changes in stratospheric aerosols on both global and local climate.
A tiny tick can cause a big health problem
Directory of Open Access Journals (Sweden)
Manuel John
2017-01-01
Full Text Available Ticks are tiny crawling bugs in the spider family that feed by sucking blood from animals. They are second only to mosquitoes as vectors of human disease, both infectious and toxic. Infected ticks spread over a hundred diseases, some of which are fatal if undetected. They spread the spirochete (which multiplies in the insect's gut with a subsequent bite to the next host. We describe the only reported cases of peri ocular tick bite from India that presented to us within a span of 3 days and its management. Due suspicion and magnification of the lesions revealed the ticks which otherwise masqueraded as small skin tags/moles on gross examination. The ticks were firmly latched on to the skin and careful removal prevented incarceration of the mouth parts. Rickettsial diseases that were believed to have disappeared from India are reemerging and their presence has recently been documented in at least 11 states in the country. Among vector borne diseases, the most common, Lyme disease, also known as the great mimicker, can present with rheumatoid arthritis, fibromyalgia, depression, attention deficit hyperactivity disorder, multiple sclerosis, chronic fatigue syndrome, cardiac manifestations, encephalitis, and mental illness, to name some of the many associations. Common ocular symptoms and signs include conjunctivitis, keratitis, uveitis, and retinitis. Early detection and treatment of tick borne diseases is important to prevent multi system complications that can develop later in life.
Directory of Open Access Journals (Sweden)
Anna Calveras
2013-05-01
Full Text Available In this paper we present the design and implementation of the Constrained Application Protocol (CoAP for TinyOS, which we refer to as TinyCoAP. CoAP seeks to apply the same application transfer paradigm and basic features of HTTP to constrained networks, while maintaining a simple design and low overhead. The design constraints of Wireless Sensor Networks (WSNs require special attention in the design process of the CoAP implementation. We argue that better performance and minimal resource consumption can be achieved developing a native library for the operating system embedded in the network. TinyOS already includes in its distribution an implementation of CoAP called CoapBlip. However, this is based on a library not originally designed to meet the requirements of TinyOS. We demonstrate the effectiveness of our approach by a comprehensive performance evaluation. In particular, we test and evaluate TinyCoAP and CoapBlip in a real scenario, as well as solutions based on HTTP. The evaluation is performed in terms of latency, memory occupation, and energy consumption. Furthermore, we evaluate the reliability of each solution by measuring the goodput obtained in a channel affected by Rayleigh fading. We also include a study on the effects that high workloads have on a server.
A tiny VIS-NIR snapshot multispectral camera
Geelen, Bert; Blanch, Carolina; Gonzalez, Pilar; Tack, Nicolaas; Lambrechts, Andy
2015-03-01
Spectral imaging can reveal a lot of hidden details about the world around us, but is currently confined to laboratory environments due to the need for complex, costly and bulky cameras. Imec has developed a unique spectral sensor concept in which the spectral unit is monolithically integrated on top of a standard CMOS image sensor at wafer level, hence enabling the design of compact, low cost and high acquisition speed spectral cameras with a high design flexibility. This flexibility has previously been demonstrated by imec in the form of three spectral camera architectures: firstly a high spatial and spectral resolution scanning camera, secondly a multichannel snapshot multispectral camera and thirdly a per-pixel mosaic snapshot spectral camera. These snapshot spectral cameras sense an entire multispectral data cube at one discrete point in time, extending the domain of spectral imaging towards dynamic, video-rate applications. This paper describes the integration of our per-pixel mosaic snapshot spectral sensors inside a tiny, portable and extremely user-friendly camera. Our prototype demonstrator cameras can acquire multispectral image cubes, either of 272x512 pixels over 16 bands in the VIS (470-620nm) or of 217x409 pixels over 25 bands in the VNIR (600-900nm) at 170 cubes per second for normal machine vision illumination levels. The cameras themselves are extremely compact based on Ximea xiQ cameras, measuring only 26x26x30mm, and can be operated from a laptop-based USB3 connection, making them easily deployable in very diverse environments.
Development of Fast Response SME TiNi Foam Torque Tubes Project
National Aeronautics and Space Administration — Shape Change Technologies (SCT) has pioneered the use of Self-propagating High Temperature Synthesis (SHS) to manufacture open celled, porous TiNi. Recently, we have...
Development of Fast Response SME TiNi Foam Torque Tubes Project
National Aeronautics and Space Administration — In Phase I, Shape Change Technologies had developed a process to manufacture net shape TiNi foam torque tubes that demonstrated the shape memory effect. The torque...
Valse romantiek : hoogleraar Tiny van Boekel over de zegeningen van modern voedsel
Boekel, van T.
2015-01-01
Kaliumcarbonaat. Mononatriumglutamaat. Calciumdinatriumethyleendiaminetetra- acetaat. Zomaar wat additieven die de voedingsindustrie in ons eten stopt. Volgens Tiny van Boekel, hoogleraar aan de Wageningen University, is daar niks mis mee. Hij verwerpt het idee dat ons eten vroeger beter was en dat
The kinetics of Cr layer coated on TiNi films for hydrogen absorption
Indian Academy of Sciences (India)
The effect of hydrogen absorption on electrical resistance with temperature for TiNi and TiNi–Cr thin films was investigated. The TiNi thin films of thickness 800 Å were deposited at different angles ( = 0°, 30°, 45°, 60° and 75°) under 10−5 Torr pressure by thermal evaporation on the glass substrate at room temperature.
TinyOS-based quality of service management in wireless sensor networks
Peterson, N.; Anusuya-Rangappa, L.; Shirazi, B.A.; Huang, R.; Song, W.-Z.; Miceli, M.; McBride, D.; Hurson, A.; LaHusen, R.
2009-01-01
Previously the cost and extremely limited capabilities of sensors prohibited Quality of Service (QoS) implementations in wireless sensor networks. With advances in technology, sensors are becoming significantly less expensive and the increases in computational and storage capabilities are opening the door for new, sophisticated algorithms to be implemented. Newer sensor network applications require higher data rates with more stringent priority requirements. We introduce a dynamic scheduling algorithm to improve bandwidth for high priority data in sensor networks, called Tiny-DWFQ. Our Tiny-Dynamic Weighted Fair Queuing scheduling algorithm allows for dynamic QoS for prioritized communications by continually adjusting the treatment of communication packages according to their priorities and the current level of network congestion. For performance evaluation, we tested Tiny-DWFQ, Tiny-WFQ (traditional WFQ algorithm implemented in TinyOS), and FIFO queues on an Imote2-based wireless sensor network and report their throughput and packet loss. Our results show that Tiny-DWFQ performs better in all test cases. ?? 2009 IEEE.
Patterning and bonding of TiNi shape memory thin film for fabrication of micropump
Makino, Eiji; Mitsuya, Takashi; Nakatsuji, Tae; Shibata, Takayuki
1999-03-01
In order to develop a micropump driven by shape memory actuation, we require a TiNi diaphragm structure with a cap to act as a chamber for applying bias pressure to the diaphragm. With the purpose of realizing such a structure, we studied the photoetching of TiNi thin film on a Si substrate and two bonding processes-diffusion bonding and anodic bonding- for patterning and assembling. TiNi thin film deposited on Si substrates by flash evaporation was etched in HF/HNO3/H2O solutions using negative photoresist masks. HF:HNO3:H2O equals 1:1:4 solution proved capable of etching it at a rate of about 30 nm/s without etching of the Si substrate. Patterned TiNi thin film of 6 micrometers in thickness on a Si substrate was diffusion bonded to another Si substrate coated with the same TiNi thin film at a thickness of 300 nm. Bonding was conducted in a vacuum at a bonding pressure of 210 MPa. TiNi-TiNi diffusion bonding was obtained at temperatures of more than 300 degrees C. A 4-point bending test revealed that the bond strength of specimens bonded at 400 degrees C was 15-20 MPa. Anodic bonding was conducted between TiNi thin film on a Si substrate and a Pyrex 7740 glass substrate at an applied voltage of 600 V. Two substrates were bonded in nitrogen ambient at temperatures of more than 350 degrees C, giving a bond strength of about 15 MPa at 400 degrees C bonding.
Fast Response Shape Memory Effect Titanium Nickel (TiNi) Foam Torque Tubes
Jardine, Peter
2014-01-01
Shape Change Technologies has developed a process to manufacture net-shaped TiNi foam torque tubes that demonstrate the shape memory effect. The torque tubes dramatically reduce response time by a factor of 10. This Phase II project matured the actuator technology by rigorously characterizing the process to optimize the quality of the TiNi and developing a set of metrics to provide ISO 9002 quality assurance. A laboratory virtual instrument engineering workbench (LabVIEW'TM')-based, real-time control of the torsional actuators was developed. These actuators were developed with The Boeing Company for aerospace applications.
Corrosion resistance and surface characterization of electrolyzed Ti-Ni alloy.
Fukushima, Osamu; Yoneyama, Takayuki; Doi, Hisashi; Hanawa, Takao
2006-03-01
Ti-Ni alloy has been increasingly applied to medical and dental devices, such as coronary stents and orthodontic wires. This alloy contains nickel, which is known to give rise to cytotoxicity, metal allergy, and carcinogenicity. Therefore, the purpose of this study was to improve the corrosion resistance of Ti-Ni alloy by electrolytic treatment, whereby investigation was carried out using different acidic electrolyte compositions. As a result, specimens electrolyzed with lactic acid, water, and glycerol were found to show higher corrosion potential and release lower amount of titanium and nickel ions than mechanical-polished specimens (ptreatment, nickel concentration in the surface oxide layer of Ti-Ni alloy decreased, and the thickness of the surface oxide layer increased. Based on the results of this study, it was shown that electrolytic treatment with suitable electrolyte could improve the corrosion resistance of Ti-Ni alloy, which is effective to produce medical and dental devices that utilize shape memory effect or superelasticity with better biocompatibility.
Face to Face MicroRNAs: Tiny Genetic Switches in Our Genome
Indian Academy of Sciences (India)
Face to Face. This section features conversations with personalities related to science, highlighting the factors and circumstances that guided them in making the career choice to be a scientist. MicroRNAs: Tiny Genetic Switches in Our Genome. Gary Ruvkun talks to Venkatesan Sundaresan. Gary Ruvkun is a winner of the ...
Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand
DEFF Research Database (Denmark)
Scott, JM; Turnbull, IM; Sagar, MW
2015-01-01
The first comprehensive geological map, a summary of lithologies and new radiogenic isotope data (U–Pb, Rb–Sr) are presented for crystalline rocks of the Sub-Antarctic Snares Islands/Tini Heke, 150 km south of Stewart Island. The main lithology is Snares Granite (c. 109 Ma from U–Pb dating...
Thermal Explosion in a Mechanically Activated Ti-Ni System: Mathematical Model
Lapshin, O. V.; Shkoda, O. A.
2017-01-01
A mathematical model of a thermal explosion in a mechanically pre-activated Ti-Ni system is constructed in a macroscopic approximation. It is found out that preliminary mechanical activation considerably accelerates the reaction product synthesis. Using the experimental data obtained earlier, the thermal and kinetic constants of the synthesis are determined.
Tiny Integrated Network Analyzer for Noninvasive Measurements of Electrically Small Antennas
DEFF Research Database (Denmark)
Buskgaard, Emil Feldborg; Krøyer, Ben; Tatomirescu, Alexandru
2016-01-01
the system. The tiny integrated network analyzer is a stand-alone Arduino-based measurement system that utilizes the transmit signal of the system under test as its reference. It features a power meter with triggering ability, on-board memory, universal serial bus, and easy extendibility with general...
Lithium storage in amorphous TiNi hydride: Electrode for rechargeable lithium-ion batteries
Energy Technology Data Exchange (ETDEWEB)
Bououdina, M., E-mail: mboudina@gmail.com [Nanotechnology Centre, College of Science, University of Bahrain, PO Box 32038 (Bahrain); Department of Physics, College of Science, University of Bahrain, PO Box 32038 (Bahrain); Oumellal, Y.; Dupont, L.; Aymard, L. [Laboratoire de Reactivite du Solid (RCS), UMR CNRS 6007, 33 rue Saint-Leu, 80039 Amiens (France); Al-Gharni, H. [Department of Electronics, University of York, York (United Kingdom); Al-Hajry, A. [Department of Physics, College of Science and Arts, Najran University, Najran (Saudi Arabia); Maark, T.A. [Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, SE-751 20 Uppsala (Sweden); De Sarkar, A. [Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden); Ahuja, R. [Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, SE-751 20 Uppsala (Sweden); Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden); Deshpande, M.D. [Department of Physics, H.P.T. Arts and R.Y.K. Science College, Nasik 422 005, Maharashtra (India); Qian, Z. [Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, SE-751 20 Uppsala (Sweden); Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden); Rahane, A.B. [Department of Physics, H.P.T. Arts and R.Y.K. Science College, Nasik 422 005, Maharashtra (India)
2013-08-15
In this study, amorphous TiNi phase was successfully prepared using mechanically milling for a very short time of 8 h. HRTEM confirms the formation of amorphous phase with the presence of nanocrystalline Fe particles. After hydrogenation (30 bars of H{sub 2} for a duration of 2 h), the electrochemical reaction shows that TiNi hydride/Li cell discharges at a current of one Li for 10 h between 3 V and 0.005 V. The discharge of TiNiH electrode around x = 1 Li corresponds to a capacity of 251 mAh g{sup −1} and a hydride composition of TiNiH{sub 1.0} at an average voltage of 0.4 V. Ex-situ X-ray diffraction pattern collected at the end of the discharge shows a mixture of amorphous TiNi compound and LiH. A general mechanism for the electrochemical reaction is then proposed: α-TiNiH + Li{sup +} + e{sup −} → α-TiNi + LiH. The results from DFT calculations yield an average cell voltage of 0.396 V, which is in good agreement with the experimental pseudo-plateau occurring at 0.4 V. - Highlights: • Synthesis of amorphous TiNi in a very short time. • Hydrogenation of amorphous TiNi phase using reactive ball milling (30 bars H{sub 2}, 2 h). • A discharge capacity of 251 mAh g{sup −1} which corresponds to TiNiH{sub 1.0} at an average voltage of 0.4 V. • Using ex-situ X-ray diffraction, a mechanism has been proposed: α-TiNiH + Li{sup +} + e{sup −} → α-TiNi + LiH. • DFT results show an average cell voltage of 0.396 V.
Franklin, Joel N
2003-01-01
Mathematically rigorous introduction covers vector and matrix norms, the condition-number of a matrix, positive and irreducible matrices, much more. Only elementary algebra and calculus required. Includes problem-solving exercises. 1968 edition.
Investigation of TiNi shape memory alloy for thermosensitive wire drive
Directory of Open Access Journals (Sweden)
Ostropiko Eugene
2015-01-01
Full Text Available TiNi shape memory alloys are nowadays widely used in engineering and medicine. The unique capabilities of this material are particularly apparent in applications for space technology. One of the actual present problems is the design of thermosensitive devices for space applications. In this work, we investigated a TiNi alloy as a working element material for the thermosensitive wire drive as an actuator. An optimum thermomechanical treatment of NiTi alloys was selected based on the analysis of functional and mechanical properties. It consists of a multi-cycle implementation of transformation plasticity under 220 MPa constant stress and a shape memory effect in the free state.
(Updated) Nanotechnology: Understanding the Tiny Particles That May Save a Life | Poster
By Nathalie Walker, Guest Writer Could nanotechnology—the study of tiny matter ranging in size from 1 to 200 nanometers—be the future of cancer treatment? Although it is a relatively new field in cancer research, nanotechnology is not new to everyday life. Have you ever thought about the tennis ball you’ve thrown with your dog at the park and wondered what it is made of? Nanotechnology is used to make the tennis ball stronger.
Bodewig, E
1959-01-01
Matrix Calculus, Second Revised and Enlarged Edition focuses on systematic calculation with the building blocks of a matrix and rows and columns, shunning the use of individual elements. The publication first offers information on vectors, matrices, further applications, measures of the magnitude of a matrix, and forms. The text then examines eigenvalues and exact solutions, including the characteristic equation, eigenrows, extremum properties of the eigenvalues, bounds for the eigenvalues, elementary divisors, and bounds for the determinant. The text ponders on approximate solutions, as well
Energy Technology Data Exchange (ETDEWEB)
Okawa, A.; Ito, Y.; Omi, M. [Tohoku University, Sendai (Japan). Institute for Advanced Materials Processing
1996-03-29
A fixture was experimentally manufactured for an artificial vessel for an aneurysm in the aorta provided with a TiNi-based shape memory alloy, and basic examinations were conducted about the elusion of Ni ions and the possibility of the installation of such an artificial vessel. A TiNi-based shape memory alloy ring was experimentally manufactured for fixing an artificial vessel on the aneurysm-affected part. For a model experimental, a 10mm-diameter 51at% Ni shape memory alloy rod was cut into a 10mm-long piece with the material being cooled by chill water, and a hollow cylinder was manufactured with its wall 0.2mm thick. After the cutting, the cylinder was heated for 30 minutes at 973K in the N2 atmosphere, and then was quenched in cold water for the accomplishment of shape memory treatment. An artificial vessel was sutured to the ring for the ring to be deformed, the product was inserted into a simulated vessel, and then steps were taken for the ring to restore its shape. The ring, however, was inadequate in its shape restoring capability. In another experiment, a needle-shaped TiNi alloy was buried in the chest of a dog for the observation of Ni ion-caused allergy, but no remarkable response was observed. 13 refs., 2 figs.
Ti-Ni Rods with Variable Stiffness for Spine Stabilization: Manufacture and Biomechanical Evaluation
Brailovski, Vladimir; Facchinello, Yann; Brummund, Martin; Petit, Yvan; Mac-Thiong, Jean-Marc
2016-03-01
A new concept of monolithic spinal rods with variable flexural stiffness is proposed to reduce the risk of adjacent segment degeneration and vertebral fracture, while providing adequate stability to the spine. The variability of mechanical properties is generated by locally annealing Ti-Ni shape memory alloy rods. Ten-minute Joule effect annealing allows the restoration of the superelasticity in the heated portion of the rod. Such processing also generates a mechanical property gradient between the heated and the unheated zones. A numerical model simulating the annealing temperature and the distributions of the mechanical properties was developed to optimize the Joule-heating strategy and to modulate the rod's overall flexural stiffness. Subsequently, the rod model was included in a finite element model of a porcine lumbar spine to study the effect of the rod's stiffness profiles on the spinal biomechanics.
Adhesion at TiNi interfaces with Ta, Mo and Si
Directory of Open Access Journals (Sweden)
Bakulin Alexander
2015-01-01
Full Text Available Atomic and electronic structure of (001 and (110 interfaces between TiNi and Ta, Mo, Si thin films are investigated by ab-initio method within density functional theory. It is shown that high adhesion properties can be attained at the Mo/TiNi(001Ti interface, whereas the work of separation of Ta and Si films from alloy is substantial less. We found that the work of separation in case of (110 interface is lower than that at (001. Structural and electronic properties of considered interfaces are analysed. Our calculations of metal-oxide interfaces demonstrate that formation of intermediate titanium oxides layers can result in decrease of adhesion at Me/TiNi(110 interfaces.
[Determination of lignin content in tiny Panax ginseng by UV spectrophotometry].
Li, Jing; Cheng, Zhou; Yang, Xiao-Ling; Li, Shan; Gu, Min; Wan, Shu-Wen; Zhang, Wen-Ju; Chen, Jia-Kuan
2006-03-01
To establish the UV spectrophotometry for determining lignin content in tiny Panax ginseng powder. Classical Klason method and UV spectrophotometry were used. The lignin contents measured by UV spectrophotometry were higher, more repeatable and accurate as comparison with the Klason method. The specific absorptance peak of ginseng lignin appeared at 260 nm. The acetyl bromide treatment of the UV spectrophotometry was processed for ginseng powder at 70 degrees C for 30 minutes. It is also concluded that the lignin contents were obvious different among various ginsengs. UV spectrophotometry is simple, accurate and just need a little materials. It is especially suitable to determine the lignin content for ginseng and other precious Chinese traditional medicines.
Microstructure and mechanical property of neutron irradiated TiNi shape memory alloy
Energy Technology Data Exchange (ETDEWEB)
Matsukawa, Y.; Suda, T.; Ohnuki, S. [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Namba, C.
1998-01-01
Microstructure and mechanical property of neutron irradiated TiNi shape memory alloy have been investigated. The doses were on the order of 10{sup 20} to 10{sup 23} n/m{sup 2}. All of the irradiation was performed below 423 K. Amorphization was confirmed after the irradiation of 1.2x10{sup 23} n/m{sup 2}. The recovery behavior of the applied strain was drastically changed after the irradiation. The breaking point of the stress-strain curve, {sigma}{sub M}, increased with increasing dose. These results indicate that amorphous phase dominates the suppression of the martensitic transformation, and causes the change in mechanical property. (author)
Tiny individuals attached to a new Silurian arthropod suggest a unique mode of brood care
Briggs, Derek E. G.; Siveter, Derek J.; Siveter, David J.; Sutton, Mark D.
2016-04-01
The ˜430-My-old Herefordshire, United Kingdom, Lagerstätte has yielded a diversity of remarkably preserved invertebrates, many of which provide fundamental insights into the evolutionary history and ecology of particular taxa. Here we report a new arthropod with 10 tiny arthropods tethered to its tergites by long individual threads. The head of the host, which is covered by a shield that projects anteriorly, bears a long stout uniramous antenna and a chelate limb followed by two biramous appendages. The trunk comprises 11 segments, all bearing limbs and covered by tergites with long slender lateral spines. A short telson bears long parallel cerci. Our phylogenetic analysis resolves the new arthropod as a stem-group mandibulate. The evidence suggests that the tethered individuals are juveniles and the association represents a complex brooding behavior. Alternative possibilities—that the tethered individuals represent a different epizoic or parasitic arthropod—appear less likely.
Efficient Data Collection and Event Boundary Detection in Wireless Sensor Networks Using Tiny Models
King, Kraig; Nittel, Silvia
Using wireless geosensor networks (WGSN), sensor nodes often monitor a phenomenon that is both continuous in time and space. However, sensor nodes take discrete samples, and an analytical framework inside or outside the WSN is used to analyze the phenomenon. In both cases, expensive communication is used to stream a large number of data samples to other nodes and to the base station. In this work, we explore a novel alternative that utilizes predictive process knowledge of the observed phenomena to minimize upstream communication. Often, observed phenomena adhere to a process with predictable behavior over time. We present a strategy for developing and running so-called 'tiny models' on individual sensor nodes that capture the predictable behavior of the phenomenon; nodes now only communicate when unexpected events are observed. Using multiple simulations, we demonstrate that a significant percentage of messages can be reduced during data collection.
Directory of Open Access Journals (Sweden)
Miguel Vences
2012-03-01
Full Text Available We describe a tiny new frog species of the genus Platypelis (Anura: Microhylidae: Cophylinae from Marojejy National Park, northeastern Madagascar. Platypelis ravus sp. nov. differs from all other known Platypelis and Cophyla species by its small size (17-19 mm snout-vent length and a combination of other morphological and bioacoustic characters. The new species seems to be most closely related to P. milloti with which it shares the principal colour pattern, but exhibits a yellow rather than red posterior venter. Uncorrected pairwise sequence divergence in a 16S rRNA gene fragment to all other known species of the genus (except P. cowanii for which no genetic data is available is greater than 6%. We suggest the inclusion of the new species in the IUCN threat category “Data Deficient”.
Development of a tiny neutron probe with an optical fibre for BNCT.
Ito, Y; Katano, G; Harano, H; Matsumoto, T; Uritani, A; Kudo, K; Kobayashi, K; Yoshimoto, T; Sakurai, Y; Kobayashi, T; Mori, C
2004-01-01
We have developed a tiny neutron probe detector as a monitor of a thermal neutron flux for boron neutron capture therapy. The detector consists of an optical fibre and a small neutron probe. We have used a film-like ZnS(Ag) scintillator and a 6LiF neutron converter for the neutron probe. In order to improve the gamma-neutron discrimination ability, vacuum evaporation of 6LiF onto the ZnS(Ag) film has been done. In order to improve the neutron detection efficiency, we made use of a wavelength-shifting fibre as the probe material. The characteristics of the above two types of fibre probe detector have been evaluated experimentally.
Directory of Open Access Journals (Sweden)
Landweber Laura F
2008-12-01
Full Text Available Abstract Background Nyctotherus ovalis is a single-celled eukaryote that has hydrogen-producing mitochondria and lives in the hindgut of cockroaches. Like all members of the ciliate taxon, it has two types of nuclei, a micronucleus and a macronucleus. N. ovalis generates its macronuclear chromosomes by forming polytene chromosomes that subsequently develop into macronuclear chromosomes by DNA elimination and rearrangement. Results We examined the structure of these gene-sized macronuclear chromosomes in N. ovalis. We determined the telomeres, subtelomeric regions, UTRs, coding regions and introns by sequencing a large set of macronuclear DNA sequences (4,242 and cDNAs (5,484 and comparing them with each other. The telomeres consist of repeats CCC(AAAACCCCn, similar to those in spirotrichous ciliates such as Euplotes, Sterkiella (Oxytricha and Stylonychia. Per sequenced chromosome we found evidence for either a single protein-coding gene, a single tRNA, or the complete ribosomal RNAs cluster. Hence the chromosomes appear to encode single transcripts. In the short subtelomeric regions we identified a few overrepresented motifs that could be involved in gene regulation, but there is no consensus polyadenylation site. The introns are short (21–29 nucleotides, and a significant fraction (1/3 of the tiny introns is conserved in the distantly related ciliate Paramecium tetraurelia. As has been observed in P. tetraurelia, the N. ovalis introns tend to contain in-frame stop codons or have a length that is not dividable by three. This pattern causes premature termination of mRNA translation in the event of intron retention, and potentially degradation of unspliced mRNAs by the nonsense-mediated mRNA decay pathway. Conclusion The combination of short leaders, tiny introns and single genes leads to very minimal macronuclear chromosomes. The smallest we identified contained only 150 nucleotides.
Pollination networks of oil-flowers: a tiny world within the smallest of all worlds.
Bezerra, Elisângela L S; Machado, Isabel C; Mello, Marco A R
2009-09-01
1. In the Neotropics, most plants depend on animals for pollination. Solitary bees are the most important vectors, and among them members of the tribe Centridini depend on oil from flowers (mainly Malpighiaceae) to feed their larvae. This specialized relationship within 'the smallest of all worlds' (a whole pollination network) could result in a 'tiny world' different from the whole system. This 'tiny world' would have higher nestedness, shorter path lengths, lower modularity and higher resilience if compared with the whole pollination network. 2. In the present study, we contrasted a network of oil-flowers and their visitors from a Brazilian steppe ('caatinga') to whole pollination networks from all over the world. 3. A network approach was used to measure network structure and, finally, to test fragility. The oil-flower network studied was more nested (NODF = 0.84, N = 0.96) than all of the whole pollination networks studied. Average path lengths in the two-mode network were shorter (one node, both for bee and plant one-mode network projections) and modularity was lower (M = 0.22 and four modules) than in all of the whole pollination networks. Extinctions had no or small effects on the network structure, with an average change in nestedness smaller than 2% in most of the cases studied; and only two species caused coextinctions. The higher the degree of the removed species, the stronger the effect and the higher the probability of a decrease in nestedness. 4. We conclude that the oil-flower subweb is more cohesive and resilient than whole pollination networks. Therefore, the Malpighiaceae have a robust pollination service in the Neotropics. Our findings reinforce the hypothesis that each ecological service is in fact a mosaic of different subservices with a hierarchical structure ('webs within webs').
Directory of Open Access Journals (Sweden)
Yong-Jin Park
2008-12-01
Full Text Available In recent years, a few protocol bridge research projects have been announced to enable a seamless integration of Wireless Sensor Networks (WSNs with the TCP/IP network. These studies have ensured the transparent end-to-end communication between two network sides in the node-centric manner. Researchers expect this integration will trigger the development of various application domains. However, prior research projects have not fully explored some essential features for WSNs, especially the reusability of sensing data and the data-centric communication. To resolve these issues, we suggested a new protocol bridge system named TinyONet. In TinyONet, virtual sensors play roles as virtual counterparts of physical sensors and they dynamically group to make a functional entity, Slice. Instead of direct interaction with individual physical sensors, each sensor application uses its own WSN service provided by Slices. If a new kind of service is required in TinyONet, the corresponding function can be dynamically added at runtime. Beside the data-centric communication, it also supports the node-centric communication and the synchronous access. In order to show the effectiveness of the system, we implemented TinyONet on an embedded Linux machine and evaluated it with several experimental scenarios.
Kreitcberg, Alena
Severe plastic deformation (SPD) is commonly used for nanostructure formation in Ti-Ni shape memory alloys (SMAs), but it increases the risk of damage during processing and, consequently, negatively affects functional fatigue resistance of these materials. The principal objective of this project is, therefore, to study the interrelations between the processing conditions, damageability during processing, microstructure and the functional properties of Ti-Ni SMAs with the aim of improving long-term functional performances of these materials by optimizing their processing conditions. First, microstructure and fatigue properties of Ti-Ni SMAs were studied after thermomechanical treatment (TMT) with different combinations of severe cold and warm rolling (CR and WR), as well as intermediate and post-deformation annealing (IA and PDA) technological steps. It was shown that either when WR and IA were introduced into the TMT schedule, or CR intensity was decreased, the fatigue life was improved as a consequence of less processing-induced damage and higher density of the favorable B2-austenite texture. This improvement was reached, however, at a price of a lower multi-cycle functional stability of these materials, the latter being a direct consequence of the microstructure coarsening after higher-temperature lower-intensity processing. At the end of this study, however, it was not possible to distinguish between contributions to the functional performances of Ti-Ni SMAs from different processing-related features: a) grain/subgrain size; b) texture; and c) level of rolling-induced defects. To be capable of separating contributions to the functional properties of Ti-Ni alloys from grain/subgrain size and from texture, the theoretical crystallographic resource of recovery strain after different TMTs and, therefore, different textures, were calculated and compared with the experiment. The comparative analysis showed that the structural factors (grain/subgrain size) strongly
Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium
Shri, D. N. Awang; Tsuchiya, K.; Yamamoto, A.
2017-09-01
In recent years there are growing interest in fabrication of bulk nanostructured metals and alloys by using severe plastic deformation (SPD) techniques as new alternative in producing bulk nanocrystalline materials. These techniques allows for processing of bulk, fully dense workpiece with ultrafine grains. Metal undergoes SPD processing in certain techniques such as high pressure torsion (HPT), equal-channel angular pressing (ECAP) or multi-directional forging (MDF) are subjected to extensive hydrostatic pressure that may be used to impart a very high strain to the bulk solid without the introduction of any significant change in overall dimension of the sample. The change in the structure (small grain size and high-volume fraction of grain boundaries) of the material may result in the corrosion behavior different from that of the coarse-grained material. Electrochemical measurements were done to understand the corrosion behavior of TiNi alloys before and after HPT deformation. The experiment was carried out using standard three electrode setup (a sample as working electrode; a platinum wire as a counter electrode and a saturated calomel electrode in saturated KCl as a reference electrode) with the surface area of 26.42 mm2 exposed to the EMEM+10% FBS cell culture medium. The measurements were performed in an incubator with controlled environment at 37 °C and 5% CO2, simulating the cell culture condition. The potential of the specimen was monitored over 1 hour, and the stabilized potential was used as the open-circuit potential (EOCP). Potentiodynamic curves were scanned in the potential range from -0.5 V to 1.5 V relative to the EOCP, at a rate of 0.5 mV/s. The result of OCP-time measurement done in the cell culture medium shows that the OCP of HPT-deformed samples shifts towards to the more positive rather than that of BHPT samples. The OCP of deformed samples were ennobled to more than +70 mV for Ti-50mol%. The shift of OCP towards the nobler direction
Wang, Houmao; Wang, Yongmei; Fu, Jianguo
2016-12-01
A tiny and low-cost ground-based Fabry-Perot interferometer (FPI) was designed using a filter behind etalon and Galilean telescope system for the thermospheric wind observation with OI 630.0 nm nightglow emissions ( 250 km). Based on the instrument, experiments were carried out at Langfang (39.40° N, 116.65° E) site for a rough comparison and Kelan (38.71° N, 111.58° E) site for a detailed validation. Wind results of Langfang experiment are well consistent with measurements of two other FPIs deployed at Xinglong (40.40° N, 117.59° E) and Kelan which are retrieved by the American National Center for Atmospheric Research (A-NCAR). In Kelan experiment, the averaged wind deviation between our FPI and A-NCAR FPI is 11.8 m/s. The averaged deviation of wind measurement error between them is 2.9 m/s. The comparisons suggest good agreement. Then, the analysis of influencing factors was made. The center determination offset has an exponential relation with wind deviation, while the radius calculation offset is linear with wind deviation.
Pieczyska, Elżbieta A.; Kowalewski, Zbigniew L.; Dunić, Vladimir Lj.
2017-12-01
This paper presents an investigation of thermomechanical effects related to the phenomena of stress relaxation occurring in TiNi SMA subjected to modified program of displacement-controlled tension. The deformation data were taken from testing machine, whereas the temperature changes accompanying the exothermic/endothermic martensite forward/reverse transformation were measured by infrared camera. At the advanced stages of the transformations, the strain was kept constant for a few minutes and the SMA load and temperature were recorded continuously. As a consequence, the stress and temperature changed significantly during the loading stops. A large stress drop, caused by the transformation, was observed during the relaxation stage in both courses of the SMA loading and unloading. Moreover, the non-uniform temperature distribution, reflecting macroscopically inhomogeneous transformation, lapsed while the strain was kept constant, yet restarted at the end of the relaxation stop and developed at the reloading stage. Along with the experimental results, the mechanical and thermal responses induced by the transformation were obtained by 3D coupled thermomechanical numerical analysis, realized in partitioned approach. Latent heat production was correlated with an amount of the martensitic volume fraction. The stress and temperature drops recorded during the experiment were satisfactorily reproduced by the model proposed for the SMA thermomechanical coupling.
Microstructure Formation in Dissimilar Metal Welds: Electron Beam Welding of Ti/Ni
Chatterjee, Subhradeep; Abinandanan, T. A.; Reddy, G. Madhusudhan; Chattopadhyay, Kamanio
2016-02-01
We present results for electron beam welding of a binary Ti/Ni dissimilar metal couple. The difference in physical properties of the base metals and metallurgical features (thermodynamics and kinetics) of the system influence both macroscopic transport and microstructure development in the weld. Microstructures near the fusion interfaces are markedly different from those inside the weld region. At the Ti side, Ti2Ni dendrites are observed to grow toward the fusion interface, while in the Ni side, layered growth of γ-Ni, Ni3Ti, and Ni3Ti + NiTi eutectic is observed. Different morphologies of the latter eutectic constitute the predominant microstructure inside the weld metal region. These results are compared and contrasted with those from laser welding of the same binary couple, and a scheme of solidification is proposed to explain the observations. This highlights notable departures from welding of similar and other dissimilar metals such as a significant asymmetry in heat transport that governs progress of solidification from each side of the couple, and a lack of unique liquidus isotherm characterizing the liquid-solid front.
Pollen--tiny and ephemeral but not forgotten: New ideas on their ecology and evolution.
Williams, Joseph H; Mazer, Susan J
2016-03-01
Ecologists and evolutionary biologists have been interested in the functional biology of pollen since the discovery in the 1800s that pollen grains encompass tiny plants (male gametophytes) that develop and produce sperm cells. After the discovery of double fertilization in flowering plants, botanists in the early 1900s were quick to explore the effects of temperature and maternal nutrients on pollen performance, while evolutionary biologists began studying the nature of haploid selection and pollen competition. A series of technical and theoretic developments have subsequently, but usually separately, expanded our knowledge of the nature of pollen performance and how it evolves. Today, there is a tremendous diversity of interests that touch on pollen performance, ranging from the ecological setting on the stigma, structural and physiological aspects of pollen germination and tube growth, the form of pollen competition and its role in sexual selection in plants, virus transmission, mating system evolution, and inbreeding depression. Given the explosion of technical knowledge of pollen cell biology, computer modeling, and new methods to deal with diversity in a phylogenetic context, we are now more than ever poised for a new era of research that includes complex functional traits that limit or enhance the evolution of these deceptively simple organisms. © 2016 Botanical Society of America.
Transformation-Induced Relaxation and Stress Recovery of TiNi Shape Memory Alloy.
Takeda, Kohei; Matsui, Ryosuke; Tobushi, Hisaaki; Pieczyska, Elzbieta A
2014-03-06
The transformation-induced stress relaxation and stress recovery of TiNi shape memory alloy (SMA) in stress-controlled subloop loading were investigated based on the local variation in temperature and transformation band on the surface of the tape in the tension test. The results obtained are summarized as follows. (1) In the loading process, temperature increases due to the exothermic martensitic transformation (MT) until the holding strain and thereafter temperature decreases while holding the strain constant, resulting in stress relaxation due to the MT; (2) In the unloading process, temperature decreases due to the endothermic reverse transformation until the holding strain and thereafter temperature increases while holding the strain constant, resulting in stress recovery due to the reverse transformation; (3) Stress varies markedly in the initial stage followed by gradual change while holding the strain constant; (4) If the stress rate is high until the holding strain in the loading and unloading processes, both stress relaxation and stress recovery are large; (5) It is important to take into account this behavior in the design of SMA elements, since the force of SMA elements varies even if the atmospheric temperature is kept constant.
An Improved Task Scheduling Algorithm for Intelligent Control in Tiny Mechanical System
Directory of Open Access Journals (Sweden)
Jialiang Wang
2014-01-01
Full Text Available Wireless sensor network (WSN has been already widely used in many fields in terms of industry, agriculture, and military, and so forth. The basic composition is WSN nodes that are capable of performing processing, gathering information, and communicating with other connected nodes in the network. The main components of a WSN node are microcontroller, transceiver, and some sensors. Undoubtedly, it also can be added with some actuators to form a tiny mechanical system. Under this case, the existence of task preemption while executing operating system will not only cost more energy for WSN nodes themselves, but also bring unacceptable system states caused by vibrations. However for these nodes, task I/O delays are inevitable due to the existence of task preemption, which will bring extra overhead for the whole system, and even bring unacceptable system states caused by vibrations. This paper mainly considers the earliest deadline first (EDF task preemption algorithm executed in WSN OS and proposes an improved task preemption algorithm so as to lower the preemption overhead and I/O delay and then improve the system performance. The experimental results show that the improved task preemption algorithm can reduce the I/O delay effectively, so the real-time processing ability of the system is enhanced.
Endemics and adventives: Thysanoptera (Insecta) biodiversity of Norfolk, a tiny Pacific Island.
Mound, Laurence A; Wells, Alice
2015-06-02
The thrips fauna of Norfolk Island is a curious mix of endemics and adventives, with notable absences that include one major trophic group. A brief introduction is provided to the history of human settlement and its ecological impact on this tiny land mass in the western Pacific Ocean. The Thysanoptera fauna comprises about 20% endemic and almost 50% widespread invasive species, and shows limited faunal relationships to the nearest territories, Australia, New Caledonia and New Zealand. This fauna, comprising 66 species, includes among named species 29 Terebrantia and 33 Tubulifera, with four Tubulifera remaining undescribed. At least 12 species are endemics, of which 10 are mycophagous, and up to 10 further species are possibly native to the island. As with the thrips fauna of most Pacific islands, many species are widespread invasives. However, most of the common thrips of eastern Australia have not been found on Norfolk Island, and the complete absence of leaf-feeding Phlaeothripinae is notable. The following new taxa are described: in the Phlaeothripidae, Buffettithrips rauti gen. et sp. n. and Priesneria akestra sp. n.; and in the Thripidae, Scirtothrips araucariae sp. n. and Thrips merae sp. n.
Bhatia, Rajendra
1997-01-01
A good part of matrix theory is functional analytic in spirit. This statement can be turned around. There are many problems in operator theory, where most of the complexities and subtleties are present in the finite-dimensional case. My purpose in writing this book is to present a systematic treatment of methods that are useful in the study of such problems. This book is intended for use as a text for upper division and gradu ate courses. Courses based on parts of the material have been given by me at the Indian Statistical Institute and at the University of Toronto (in collaboration with Chandler Davis). The book should also be useful as a reference for research workers in linear algebra, operator theory, mathe matical physics and numerical analysis. A possible subtitle of this book could be Matrix Inequalities. A reader who works through the book should expect to become proficient in the art of deriving such inequalities. Other authors have compared this art to that of cutting diamonds. One first has to...
Energy Technology Data Exchange (ETDEWEB)
Yamauchi, K. (Tokin Corporation, Sendai (Japan)); Inaba, T. (Nishimatsu Construction Co. Ltd., Tokyo (Japan)); Kaneko, K. (Kumamoto University, Kumamoto (Japan))
1992-06-20
Development has been made on a static rock breaker using TiNi shape memory alloy as a solid pressure source to break rocks and concrete structures. An experiment was carried out to find TiNi alloy composition and treatment conditions in which shape restoration characteristics after compression become optimal as a pressure source for the breaker. A comprehensive judgment over the experimental result concluded that the optimal material is a low-temperature annealed Ni alloy with Ti at 50.5 by atom (annealed after having been retained at 400{degree}C for one hour). The procedure for its use is as follows: Insert the breaker mounted with pre-compressed TiNi alloy into a bore hole. When the alloy is applied with electric power and heated, the alloy generates a restoring power and attempts to return to the shape before the compression. This movement gives a single axial compression load to the hole wall from which cracks develop in a direction perpendicular to the loading axis. The alloy can be used over when the initial compression is given after a crushing has been performed. A site test to break reinforced concrete and andesite proved the breaker to work satisfactorily for both cases. 11 refs., 5 figs., 2 tabs.
Skiles, M.
2016-12-01
Groups of tiny ice pieces fall from the sky in the cold times and cover the high places. Later, the tiny ice pieces become water that moves to the lower places, where people can use it for drinking and stuff. The time when the tiny ice pieces turn to water is controlled by the sun. New tiny ice pieces from the sky, which are very white and don't take up much sun, group up and grow tall. When they become dark from getting old and large, and from getting covered in tiny dark bits from the sky, they take up more sun and turn to water. The more tiny dark bits, the faster they become water. Using a flying thing over the high places we can see how much water will come from the cover of tiny ice pieces by using ground looking things to see how tall it is, and and when it will become water by using picture taking things to see how much sun is taken up. The low places are happy to know how much water is in the high places.
Beisser, K.; Cruikshank, D. P.; McFadden, T.
2013-12-01
Is Pluto a planet? Some creative low income Bay-area middle-schoolers put a musical spin on this hot science debate with a video rap ';battle' over tiny Pluto's embattled planetary standing. The students' timing was perfect, with NASA's New Horizons mission set to conduct the first reconnaissance of Pluto and its moons in July 2015. Pluto - the last of the nine original planets to be explored by spacecraft - has been the subject of scientific study and speculation since Clyde Tombaugh discovered it in 1930, orbiting the Sun far beyond Neptune. Produced by the students and a very creative educator, the video features students 'battling' back and forth over the idea of Pluto being a planet. The group collaborated with actual space scientists to gather information and shot their video before a 'green screen' that was eventually filled with animations and visuals supplied by the New Horizons mission team. The video debuted at the Pluto Science Conference in Maryland in July 2013 - to a rousing response from researchers in attendance. The video marks a nontraditional approach to the ongoing 'great planet debate' while educating viewers on a recently discovered region of the solar system. By the 1990s, researchers had learned that Pluto possessed multiple exotic ices on its surface, a complex atmosphere and seasonal cycles, and a large moon (Charon) that likely resulted from a giant impact on Pluto itself. It also became clear that Pluto was no misfit among the planets - as had long been thought - but the largest and brightest body in a newly discovered 'third zone' of our planetary system called the Kuiper Belt. More recent observations have revealed that Pluto has a rich system of satellites - five known moons - and a surface that changes over time. Scientists even speculate that Pluto may possess an internal ocean. For these and other reasons, the 2003 Planetary Decadal Survey ranked a Pluto/Kuiper Belt mission as the highest priority mission for NASA's newly created
Energy Technology Data Exchange (ETDEWEB)
Zhang, Junsong; Hao, Shijie; Jiang, Daqiang; Huan, Yong; Cui, Lishan; Liu, Yinong; Yang, Hong; Ren, Yang
2017-05-01
This study explored a novel intermetallic composite design concept based on the principle of lattice strain matching enabled by the collective atomic load transfer. It investigated the hard-soft microscopic deformation behavior of a Ti3Sn/TiNi eutectic hard-soft dual phase composite by means of in situ synchrotron high-energy X-ray diffraction (HE-XRD) during compression. The composite provides a unique micromechanical system with distinctive deformation behaviors and mechanisms from the two components, with the soft TiNi matrix deforming in full compliance via martensite variant reorientation and the hard Ti3Sn lamellae deforming predominantly by rigid body rotation, producing a crystallographic texture for the TiNi matrix and a preferred alignment for the Ti3Sn lamellae. HE-XRD reveals continued martensite variant reorientation during plastic deformation well beyond the stress plateau of TiNi. The hard and brittle Ti3Sn is also found to produce an exceptionally large elastic strain of 1.95% in the composite. This is attributed to the effect of lattice strain matching between the transformation lattice distortion of the TiNi matrix and the elastic strain of Ti3Sn lamellae. With such unique micromechanic characteristics, the composite exhibits high strength and large ductility.
Energy Technology Data Exchange (ETDEWEB)
Ali, Mubarak, E-mail: mubarak74@comsats.edu.pk, E-mail: mubarak74@mail.com [COMSATS Institute of Information Technology, Department of Physics (Pakistan); Lin, I-Nan [Tamkang University, Department of Physics (China)
2017-01-15
In addition to self-governing properties, tiny-sized particles of metallic colloids are the building blocks of large-sized particles; thus, their study has been the subject of a large number of publications. In the present work, it has been discussed that geometry structure of tiny particle made through atom-to-atom amalgamation depends on attained dynamics of gold atoms along with protruded orientations. The localized process conditions direct two-dimensional structure of a tiny particle at atomically flat air-solution interface while heating locally dynamically approached atoms, thus, negate the role of van der Waals interactions. At electronphoton-solution interface, impinging electrons stretch or deform atoms of tiny particles depending on the mechanism of impingement. In addition, to strike regular grid of electrons ejected on split of atoms not executing excitations and de-excitations of their electrons, atoms of tiny particles also deform or stretch while occupying various sites depending on the process of synergy. Under suitable impinging electron streams, those tiny particles in monolayer two-dimensional structure electron states of their atoms are diffused in the direction of transferred energy, thus, coincide to the next adjacent atoms in each one-dimensional array dealing the same sort of behavior. Instantaneously, photons of adequate energy propagate on the surfaces of such electronic structures and modify those into smooth elements, thus, disregard the phenomenon of localized surface plasmons. This study highlights the fundamental process of formation of tiny particles where the role of localized dynamics of atoms and their electronic structure along with interaction to light are discussed. Such a tool of processing materials, in nonequilibrium pulse-based process, opens a number of possibilities to develop engineered materials with specific chemical, optical, and electronic properties.
Evolution of Structural-Phase States in TiNi Surface Layers Synthesized by Electron Beam Treatment
Directory of Open Access Journals (Sweden)
L. L. Meisner
2010-01-01
Full Text Available The paper presents the results of X-ray diffraction analysis of nonequilibrium structural and elastic stress states in TiNi surface layers irradiated by low-energy electron beams. It is found that a surface layer with a mixed (2D columnar and 3D equiaxial submicrocrystalline structure is formed on the irradiated side of the TiNi specimens, and the volume fractions of the two structure types depend on the beam energy parameters and number of pulses. The B2 phase synthesized in the layer is characterized by lattice microstrain due to stresses of the first and second kinds (εI≈±1%, εII=0.25%, and the layer as such is an internal stress concentrator for underlying layers of the material. In the intermediate layer beneath the stress concentrator, relaxation of irradiation-induced internal stress takes place. It is shown that the main mechanism of the relaxation is partial B2→B19′ martensite transformation. The B19′ martensite phase in the intermediate layer decreases the microstrain in the conjugate B2 phase. The thickness of the layer in which the relaxation processes develop through the B2→B19′ martensite transformation is 10–15 μm.
Hoang, H.; Røed, K.; Bekkeng, T. A.; Trondsen, E.; Clausen, L. B. N.; Miloch, W. J.; Moen, J. I.
2017-11-01
A method for evaluating electron density using a single fixed-bias Langmuir probe is presented. The technique allows for high-spatio-temporal resolution electron density measurements, which can be effectively carried out by tiny spacecraft for multi-point observations in the ionosphere. The results are compared with the multi-needle Langmuir probe system, which is a scientific instrument developed at the University of Oslo comprising four fixed-bias cylindrical probes that allow small-scale plasma density structures to be characterized in the ionosphere. The technique proposed in this paper can comply with the requirements of future small-sized spacecraft, where the cost-effectiveness, limited space available on the craft, low power consumption and capacity for data-links need to be addressed. The first experimental results in both the plasma laboratory and space confirm the efficiency of the new approach. Moreover, detailed analyses on two challenging issues when deploying the DC Langmuir probe on a tiny spacecraft, which are the limited conductive area of the spacecraft and probe surface contamination, are presented in the paper. It is demonstrated that the limited conductive area, depending on applications, can either be of no concern for the experiment or can be resolved by mitigation methods. Surface contamination has a small impact on the performance of the developed probe.
Lin, Q. S.; Zhou, K. S.; Deng, C. M.; Liu, M.; Xu, L. P.; Deng, C. G.
2014-08-01
Three kinds of Ti-Ni powders were deposited on 316L stainless steel by low-temperature high-velocity oxygen fuel (LT-HVOF) spraying process, respectively. Deposition mechanisms and oxidation behaviors of the coatings were researched in this paper. The coating deposited from TiNi intermetallic powder had obvious laminar structure and the oxygen content was the highest among the three kinds of coatings. The oxygen content of the coating deposited from small-sized Ni-clad Ti powder was still high due to the melting of parts of particles. However, most of the coarse Ni-clad Ti powder was deposited in solid states without changes of chemical compositions and phase compositions. The oxygen content of the coating deposited from coarse Ni-clad Ti powder was the lowest among the three kinds of coatings. It indicated that the deposition behavior of the coating could effectively preserve the inner titanium from oxidation. The results of the present research demonstrated that it is entirely feasible to deposit active metal materials such as titanium and titanium alloy through the optimizing selection of powder in the LT-HVOF process.
Energy Technology Data Exchange (ETDEWEB)
Pina, E.A.C.; Araujo Filho, O.O. de; Urtiga Filho, S.L.; Gonzalez, C.H., E-mail: kikipina@hotmail.co [Universidade Federal de Pernambuco (DEM/CTG/UFPE), Recife, PE (Brazil). Centro de Tecnologia e Geociencias. Dept. de Engenharia Mecanica
2010-07-01
This work aims to characterize the wire commercial Ti-Ni of 1.27 mm in diameter with shape memory effect for the development of helical springs with the function of sensor / actuator. After heat treatment, the transformation temperatures, the presence of precipitates, the degree of damping, maximum stress of rupture, modulus of elasticity, the presence of phase R, the behavior of the alloy under tension, will be analyzed and compared in each situation. For characterization we used several methods including: heat treatment, Differential Scanning Calorimetry (DSC), tensile, dynamic mechanical analysis (DMA), X-ray diffraction, thermomechanical cycling. The wires were cut into pieces and heat-treated at 400 deg C with variation of time in muffle furnaces and quenching in water at 25 deg C. (author)
Matrix completion by deep matrix factorization.
Fan, Jicong; Cheng, Jieyu
2017-11-03
Conventional methods of matrix completion are linear methods that are not effective in handling data of nonlinear structures. Recently a few researchers attempted to incorporate nonlinear techniques into matrix completion but there still exists considerable limitations. In this paper, a novel method called deep matrix factorization (DMF) is proposed for nonlinear matrix completion. Different from conventional matrix completion methods that are based on linear latent variable models, DMF is on the basis of a nonlinear latent variable model. DMF is formulated as a deep-structure neural network, in which the inputs are the low-dimensional unknown latent variables and the outputs are the partially observed variables. In DMF, the inputs and the parameters of the multilayer neural network are simultaneously optimized to minimize the reconstruction errors for the observed entries. Then the missing entries can be readily recovered by propagating the latent variables to the output layer. DMF is compared with state-of-the-art methods of linear and nonlinear matrix completion in the tasks of toy matrix completion, image inpainting and collaborative filtering. The experimental results verify that DMF is able to provide higher matrix completion accuracy than existing methods do and DMF is applicable to large matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.
Richert, Bertrand; Caucanas, Marie; André, Josette
2015-04-01
Diagnosing nail matrix diseases requires knowledge of the nail matrix function and anatomy. This allows recognition of the clinical manifestations and assessment of potential surgical risk. Nail signs depend on the location within the matrix (proximal or distal) and the intensity, duration, and extent of the insult. Proximal matrix involvement includes nail surface irregularities (longitudinal lines, transverse lines, roughness of the nail surface, pitting, and superficial brittleness), whereas distal matrix insult induces longitudinal or transverse chromonychia. Clinical signs are described and their main causes are listed to enable readers to diagnose matrix disease from the nail's clinical features. Copyright © 2015 Elsevier Inc. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Wang, Qi; Wang, Junting; Lu, Qingyou, E-mail: qxl@ustc.edu.cn [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China); Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hou, Yubin [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China)
2013-11-15
We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d{sub 31} coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.
Wang, Qi; Hou, Yubin; Wang, Junting; Lu, Qingyou
2013-11-01
We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d31 coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.
Energy Technology Data Exchange (ETDEWEB)
Meisner, L. L., E-mail: llm@ispms.tsc.ru; Meisner, S. N., E-mail: msn@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Tverdokhlebova, A. V., E-mail: a@vtverd.ru; Poletika, T. M., E-mail: poletm@ispms.tsc.ru; Girsova, S. L., E-mail: girs@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)
2015-10-27
The study was carried on for the implanted single TiNi crystal containing misoriented localized shear mesobands in its near-surface layer [001] B2. Due to the response of material to the Si ion implantation treatment of the single TiNi crystal, deformation mesobands would form in its near-surface layer. Specially designed software tools were employed for the treatment of experimental data obtained from X-ray and electron diffraction patterns. The 3D crystallographic orientations were calculated for the localized shear regions, which were displaced relative to one another and with respect to the original monocrystal orientation.
DEFF Research Database (Denmark)
Petersen, Kaare Brandt; Pedersen, Michael Syskind
Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices.......Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices....
Matrix differentiation formulas
Usikov, D. A.; Tkhabisimov, D. K.
1983-01-01
A compact differentiation technique (without using indexes) is developed for scalar functions that depend on complex matrix arguments which are combined by operations of complex conjugation, transposition, addition, multiplication, matrix inversion and taking the direct product. The differentiation apparatus is developed in order to simplify the solution of extremum problems of scalar functions of matrix arguments.
Matrix with Prescribed Eigenvectors
Ahmad, Faiz
2011-01-01
It is a routine matter for undergraduates to find eigenvalues and eigenvectors of a given matrix. But the converse problem of finding a matrix with prescribed eigenvalues and eigenvectors is rarely discussed in elementary texts on linear algebra. This problem is related to the "spectral" decomposition of a matrix and has important technical…
Parce, J. Wallace; Bernatis, Paul; Dubrow, Robert; Freeman, William P.; Gamoras, Joel; Kan, Shihai; Meisel, Andreas; Qian, Baixin; Whiteford, Jeffery A.; Ziebarth, Jonathan
2010-01-12
Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and/or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.
Hsieh, Shy-Feng; Ou, Shih-Fu; Chou, Chia-Kai
2017-01-01
TiNi shape memory alloys (SMAs), used as long-term implant materials, have a disadvantage. Ni-ion release from the alloys may trigger allergies in the human body. Micro-arc oxidation has been utilized to modify the surface of the TiNi SMA for improving its corrosion resistance and biocompatibility. However, there are very few reports investigating the essential adhesive strength between the micro-arc oxidized film and TiNi SMA. Two primary goals were attained by this study. First, Ti50Ni48.5Mo1.5 SMA having a phase transformation temperature (Af) less than body temperature and good shape recovery were prepared. Next, the Ti50Ni50 and Ti50Ni48.5Mo1.5 SMA surfaces were modified by micro-arc oxidation in phosphoric acid by applying relatively low voltages to maintain the adhesive strength. The results indicated that the pore size, film thickness, and P content increased with applied voltage. The micro-arc oxidized film, comprising Ti oxides, Ni oxide, and phosphate compounds, exhibited a glassy amorphous structure. The outmost surface of the micro-arc oxidized film contained a large amount of P (>12 at%) but only a trace of Ni (<5 at%). The adhesive strengths of all the micro-arc oxidized films exceeded the requirements of ISO 13779. Furthermore, Mo addition into TiNi SMAs was found to be favorable for improving the adhesive strength of the micro-arc oxidized film.
Energy Technology Data Exchange (ETDEWEB)
Meisner, L. L., E-mail: llm@ispms.tsc.ru; Meisner, S. N., E-mail: msn@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Markov, A. B., E-mail: a.markov@hq.tsc.ru; Yakovlev, E. V., E-mail: yakovev@lve.hcei.tsc.ru; Ozur, G. E., E-mail: ozur@lve.hcei.tsc.ru [Institute of High Current Electronics SB RAS, Tomsk, 634055 (Russian Federation); Rotshtein, V. P., E-mail: vrotshtein@yahoo.com [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Tomsk State Pedagogical University, Tomsk, 634050 (Russian Federation); Mironov, Yu. P., E-mail: myp@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)
2015-10-27
This work comprises a study of the influence of the pulse number of low-energy high-current electron beam (LEHCEB) exposure on the value and character of distribution of residual elastic stresses, texturing effects and the relationship between structural-phase states and physical and mechanical properties of the modified surface layers of TiNi alloy. LEHCEB processing of the surface of TiNi samples was carried out using a RITM-SP [3] installation. Energy density of electron beam was constant at E{sub s} = 3.9 ± 0.5 J/cm{sup 2}; pulse duration was 2.8 ± 0.3 μs. The number of pulses in the series was changeable, (n = 2–128). It was shown that as the result of multiple LEHCEB processing of TiNi samples, hierarchically organized multilayer structure is formed in the surface layer. The residual stress field of planar type is formed in the modified surface layer as following: in the direction of the normal to the surface the strain component ε{sub ⊥} < 0 (compressing strain), and in a direction parallel to the surface, the strain component ε{sub ||} > 0 (tensile deformation). Texturing effects and the level of residual stresses after LEHCEB processing of TiNi samples with equal energy density of electron beam (∼3.8 J/cm{sup 2}) depend on the number of pulses and increase with the rise of n > 10.
Meisner, L. L.; Markov, A. B.; Ozur, G. E.; Rotshtein, V. P.; Yakovlev, E. V.; Meisner, S. N.; Poletika, T. M.; Girsova, S. L.; Semin, V. O.; Mironov, Yu P.
2017-05-01
TiNi shape memory alloys (SMAs) are unique metallic biomaterials due to combination of superelastisity and high corrosion resistance. Important factors limiting biomedical applications of TiNi SMAs are a danger of toxic Ni release into the adjacent tissues, as well as insufficient level of X-ray visibility. In this paper, the method for fabrication of protective Ni-free surface alloy of thickness ∼1 μm of near Ti70Ta30 composition on TiNi SMA substrate has been successfully realized. The method is based on multiple alternation of magnetron co-deposition of Ti70Ta30 thin (50 nm) films and their liquid-phase mixing with the TiNi substrate by microsecond low-energy, high current electron beam (≤15 keV, ∼2 J/cm2) using setup RITM-SP (Microsplav, Russia). It was found by AES, XRD, SEM/EDS and HRTEM/EDS examinations, that Ti-Ta surface alloy has an increased X-ray visibility and gradient multiphase amorphous-nanocrystalline structure containing nanopores.
SenStick: Comprehensive Sensing Platform with an Ultra Tiny All-In-One Sensor Board for IoT Research
National Research Council Canada - National Science Library
Yugo Nakamura; Yutaka Arakawa; Takuya Kanehira; Masashi Fujiwara; Keiichi Yasumoto
2017-01-01
... (ultra tiny all-in-one sensor board), software (iOS, Android, and PC), and 3D case data. The platform aims to allow all the researchers to start IoT research, such as activity recognition and context estimation, easily and efficiently...
Energy Technology Data Exchange (ETDEWEB)
Neiman, A.A., E-mail: nasa@ispms.tsc.ru [Institute of Strength Physicists and Materials Science SB RAS, Tomsk (Russian Federation); Meisner, L.L. [Institute of Strength Physicists and Materials Science SB RAS, Tomsk (Russian Federation); National Research Tomsk State University, Tomsk (Russian Federation); Lotkov, A.I. [Institute of Strength Physicists and Materials Science SB RAS, Tomsk (Russian Federation); Koval, N.N. [National Research Tomsk State University, Tomsk (Russian Federation); Institute of High Current Electronics SB RAS, Tomsk (Russian Federation); Semin, V.O. [Institute of Strength Physicists and Materials Science SB RAS, Tomsk (Russian Federation); National Research Tomsk State University, Tomsk (Russian Federation); Teresov, A.D. [National Research Tomsk State University, Tomsk (Russian Federation); Institute of High Current Electronics SB RAS, Tomsk (Russian Federation)
2015-02-01
Highlights: • The TiNi melted layer is characterized by changing of chemical composition for the Ti enrichment. • Structure of the B2 phase in the modified zone has considerable distortions of the crystal lattice. • Gradient character of changes of TiNi structure in the modified zone is experimentally shown. - Abstract: The paper reports on a study of structural phase states and their cross-sectional in-depth evolution from the surface of TiNi specimens treated by low-energy high-current electron beams with surface melting at a beam energy density E = 10 J/cm{sup 2}, number of pulses N = 10, and pulse duration τ = 50 μs. After treatment, the modified TiNi surface zone takes on a layered structure in which each layer differs in phase composition and structural phase state. It is found that the melted layer is 8–10 μm thick. This layer is in a single-B2 phase state with distorted structure, lattice parameters a = b = 3.003–3.033 Å, c = 3.033–3.063 Å and α = 89.3–90°, β = γ = 90°, quasihomogeneous chemical composition corresponding to Ti{sub 51.7}Ni{sub 48.3}, the preferred orientations of the crystallites in a direction close to 〈4 1 0〉{sub B2}, and inhomogeneous lattice strain. The intermediate layer contains, in addition to the B2 phase, a B19′ martensite phase. The structural state of the B2 phase in this layer is close to equilibrium and its parameters approximate those of the initial B2 phase in nonirradiated TiNi specimens.
Berrier, Allison L; Yamada, Kenneth M
2007-12-01
The complex interactions of cells with extracellular matrix (ECM) play crucial roles in mediating and regulating many processes, including cell adhesion, migration, and signaling during morphogenesis, tissue homeostasis, wound healing, and tumorigenesis. Many of these interactions involve transmembrane integrin receptors. Integrins cluster in specific cell-matrix adhesions to provide dynamic links between extracellular and intracellular environments by bi-directional signaling and by organizing the ECM and intracellular cytoskeletal and signaling molecules. This mini review discusses these interconnections, including the roles of matrix properties such as composition, three-dimensionality, and porosity, the bi-directional functions of cellular contractility and matrix rigidity, and cell signaling. The review concludes by speculating on the application of this knowledge of cell-matrix interactions in the formation of cell adhesions, assembly of matrix, migration, and tumorigenesis to potential future therapeutic approaches. 2007 Wiley-Liss, Inc.
Parallelism in matrix computations
Gallopoulos, Efstratios; Sameh, Ahmed H
2016-01-01
This book is primarily intended as a research monograph that could also be used in graduate courses for the design of parallel algorithms in matrix computations. It assumes general but not extensive knowledge of numerical linear algebra, parallel architectures, and parallel programming paradigms. The book consists of four parts: (I) Basics; (II) Dense and Special Matrix Computations; (III) Sparse Matrix Computations; and (IV) Matrix functions and characteristics. Part I deals with parallel programming paradigms and fundamental kernels, including reordering schemes for sparse matrices. Part II is devoted to dense matrix computations such as parallel algorithms for solving linear systems, linear least squares, the symmetric algebraic eigenvalue problem, and the singular-value decomposition. It also deals with the development of parallel algorithms for special linear systems such as banded ,Vandermonde ,Toeplitz ,and block Toeplitz systems. Part III addresses sparse matrix computations: (a) the development of pa...
Quasiclassical Random Matrix Theory
Prange, R. E.
1996-01-01
We directly combine ideas of the quasiclassical approximation with random matrix theory and apply them to the study of the spectrum, in particular to the two-level correlator. Bogomolny's transfer operator T, quasiclassically an NxN unitary matrix, is considered to be a random matrix. Rather than rejecting all knowledge of the system, except for its symmetry, [as with Dyson's circular unitary ensemble], we choose an ensemble which incorporates the knowledge of the shortest periodic orbits, th...
Kennedy, May G; Genderson, Maureen Wilson; Sepulveda, Allison L; Garland, Sheryl L; Wilson, Diane Baer; Stith-Singleton, Rose; Dubuque, Susan
2013-05-01
Pregnant African American women are at disproportionately high risk of premature birth and infant mortality, outcomes associated with cigarette smoking. Telephone-based, individual smoking cessation counseling has been shown to result in successful quit attempts in the general population and among pregnant women, but "quitlines" are underutilized. A social marketing campaign called One Tiny Reason to Quit (OTRTQ) promoted calling a quitline (1-800-QUIT-NOW) to pregnant, African American women in Richmond, Virginia, in 2009 and was replicated there 2 years later. The campaign disseminated messages via radio, interior bus ads, posters, newspaper ads, and billboards. Trained volunteers also delivered messages face-to-face and distributed branded give-away reminder items. The number of calls made from pregnant women in the Richmond area during summer 2009 was contrasted with (a) the number of calls during the seasons immediately before and after the campaign, and (b) the number of calls the previous summer. The replication used the same evaluation design. There were statistically significant spikes in calls from pregnant women during both campaign waves for both types of contrasts. A higher proportion of the calls from pregnant women were from African Americans during the campaign. A multimodal quitline promotion like OTRTQ should be considered for geographic areas with sizable African American populations and high rates of infant mortality.
Genderson, Maureen Wilson; Sepulveda, Allison L.; Garland, Sheryl L.; Wilson, Diane Baer; Stith-Singleton, Rose; Dubuque, Susan
2013-01-01
Abstract Introduction Pregnant African American women are at disproportionately high risk of premature birth and infant mortality, outcomes associated with cigarette smoking. Telephone-based, individual smoking cessation counseling has been shown to result in successful quit attempts in the general population and among pregnant women, but “quitlines” are underutilized. A social marketing campaign called One Tiny Reason to Quit (OTRTQ) promoted calling a quitline (1-800-QUIT-NOW) to pregnant, African American women in Richmond, Virginia, in 2009 and was replicated there 2 years later. Methods The campaign disseminated messages via radio, interior bus ads, posters, newspaper ads, and billboards. Trained volunteers also delivered messages face-to-face and distributed branded give-away reminder items. The number of calls made from pregnant women in the Richmond area during summer 2009 was contrasted with (a) the number of calls during the seasons immediately before and after the campaign, and (b) the number of calls the previous summer. The replication used the same evaluation design. Results There were statistically significant spikes in calls from pregnant women during both campaign waves for both types of contrasts. A higher proportion of the calls from pregnant women were from African Americans during the campaign. Conclusion A multimodal quitline promotion like OTRTQ should be considered for geographic areas with sizable African American populations and high rates of infant mortality. PMID:23621745
Energy Technology Data Exchange (ETDEWEB)
Nishida, M.; Ohgi, H.; Itai, I.; Chiba, A. [Kumamoto Univ. (Japan). Dept. of Materials Science and Resource Engineering; Yamauchi, K. [Tokin Corp., Sendai (Japan). Materials Science and Development Lab.
1995-03-01
Twins in the B19{prime} martensite in the Ti-Ni shape memory alloy have been investigated by conventional transmission electron microscopy (CTEM) and electron diffraction. The following five twinning modes were observed. The <011> Type II twin was dominantly observed among those and confirmed to be a lattice invariant shear since most martensite variants consisted of the <011> Type II twinning. The {l_brace}11{bar 1}{r_brace} Type I twinning was morphologically and characteristically divided into three types, i.e. a deformation twin, a variant accommodation twin and a lattice invariant shear. (100) and (001) compound twinnings were considered to be a deformation twin. The {l_brace}011{r_brace} Type I twinning was inevitably reconfirmed and considered to be a lattice invariant shear rather than a deformation twin since it extended over the whole martensite plate. The formation order and mechanism of each twinning mode were qualitatively discussed in view of the elastic interaction accumulated during the martensitic transformation.
Warrant, Eric J
2017-04-05
Nocturnal insects have evolved remarkable visual capacities, despite small eyes and tiny brains. They can see colour, control flight and land, react to faint movements in their environment, navigate using dim celestial cues and find their way home after a long and tortuous foraging trip using learned visual landmarks. These impressive visual abilities occur at light levels when only a trickle of photons are being absorbed by each photoreceptor, begging the question of how the visual system nonetheless generates the reliable signals needed to steer behaviour. In this review, I attempt to provide an answer to this question. Part of the answer lies in their compound eyes, which maximize light capture. Part lies in the slow responses and high gains of their photoreceptors, which improve the reliability of visual signals. And a very large part lies in the spatial and temporal summation of these signals in the optic lobe, a strategy that substantially enhances contrast sensitivity in dim light and allows nocturnal insects to see a brighter world, albeit a slower and coarser one. What is abundantly clear, however, is that during their evolution insects have overcome several serious potential visual limitations, endowing them with truly extraordinary night vision.This article is part of the themed issue 'Vision in dim light'. © 2017 The Author(s).
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt; Ibsen-Jensen, Rasmus; Podolskii, Vladimir V.
2013-01-01
For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for image win–lose–draw games (i.e. image matrix games) nonzero probabilities smaller than image are never needed. We also construct an explicit image win–lose game such that the unique optimal...
Markowski, Adam S; Mannan, M Sam
2008-11-15
A risk matrix is a mechanism to characterize and rank process risks that are typically identified through one or more multifunctional reviews (e.g., process hazard analysis, audits, or incident investigation). This paper describes a procedure for developing a fuzzy risk matrix that may be used for emerging fuzzy logic applications in different safety analyses (e.g., LOPA). The fuzzification of frequency and severity of the consequences of the incident scenario are described which are basic inputs for fuzzy risk matrix. Subsequently using different design of risk matrix, fuzzy rules are established enabling the development of fuzzy risk matrices. Three types of fuzzy risk matrix have been developed (low-cost, standard, and high-cost), and using a distillation column case study, the effect of the design on final defuzzified risk index is demonstrated.
Directory of Open Access Journals (Sweden)
Mauricio Valenzuela
2017-10-01
Full Text Available We propose a hybrid class of theories for higher spin gravity and matrix models, i.e., which handle simultaneously higher spin gravity fields and matrix models. The construction is similar to Vasiliev’s higher spin gravity, but part of the equations of motion are provided by the action principle of a matrix model. In particular, we construct a higher spin (gravity matrix model related to type IIB matrix models/string theory that have a well defined classical limit, and which is compatible with higher spin gravity in A d S space. As it has been suggested that higher spin gravity should be related to string theory in a high energy (tensionless regime, and, therefore to M-Theory, we expect that our construction will be useful to explore concrete connections.
Phukaoluan, Aphinan; Khantachawana, Anak; Kaewtatip, Pongpan; Dechkunakorn, Surachai; Anuwongnukroh, Niwat; Santiwong, Peerapong; Kajornchaiyakul, Julathep
2017-03-01
In sliding mechanics, frictional force is an important counter-balancing element to orthodontic tooth movement, which must be controlled in order to allow application of light continuous forces. The purpose of this study was to compare the frictional forces between a stainless steel bracket and five different wire alloys under dry and wet (artificial saliva) conditions. TiNi, TiNiCu, TiNiCo, commercial wires A and commercial wires B with equal dimensions of 0.016×0.022'' were tested in this experiment. The stainless steel bracket was chosen with a slot dimension of 0.022''. Micro-hardness of the wires was measured by the Vickers micro-hardness test. Surface topography of wires was measured by an optical microscope and quantified using surface roughness testing. Static and kinetic friction forces were measured using a custom-designed apparatus, with a 3-mm stretch of wire alloy at a crosshead speed of 1mm/min. The static and dynamic frictions in the wet condition tended to decrease more slowly than those in the dry condition. Therefore, the friction of TiNiCu and commercial wires B would increase. Moreover, these results were associated with scarred surfaces, i.e. the increase in friction would result in a larger bracket microfracture. From the results, it is seen that copper addition resulted in an increase in friction under both wet and dry conditions. However, the friction in the wet condition was less than that in dry condition due to the lubricating effect of artificial saliva. Copyright © 2016 CEO. Published by Elsevier Masson SAS. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Tsuchiyama, Tomoya; Terasaki, Shuichi; Kaneko, Shuichi; Kaji, Kyosuke; Kobayashi, Kenichi; Matsui, Osamu [Kanazawa Univ. (Japan). Hospital
2002-10-01
It is important to distinguish small lesions with increased arterial perfusion observed by computed tomographic arteriography (CT-A) from hepatocellular carcinoma (HCC). However, the clinical characteristics and prognosis of such lesions have not been clarified. We retrospectively examined 200 patients with cirrhosis related to hepatitis C virus (HCV) infection who had undergone both CT-A and CT arterioportography between 1995 and 1998, and found 80 tiny staining spots (TSS)s, with a diameter of 5-10 mm, by CT-A (35 patients). The mean TSS observation period was 29.0 months. If the major axis was larger than 10 mm and showed a 1.5-fold or more increase, the lesion was regarded as tumor growth (TG). The TSS lesions were divided into two groups according to whether the patient had or did not have HCC. The prognosis of TSS was classified into three groups; HCC-suspected group, nontumor group, and unclassified group, in which TG was negative although transcatheter arterial embolization (TAE) had been performed. Of the 40 TSSs in 14 patients without HCC, 2 (5%) were suspected as HCC. Of the 40 TSSs in 21 patients with HCC, 13 (32.5%) were suspected as HCC. There were no significant differences in the size, position, and morphology of TSSs among the three prognostic groups. Of the 7 TSSs with a high signal intensity on T2-weighted magnetic resonance (MR) images, 5 were in the HCC-suspected group. We recommend early treatment of TSSs accompanying HCC or showing features of malignancy at the imaging workup. (author)
Digital Repository Service at National Institute of Oceanography (India)
Bhat, S.R.
at least 50 million dollars annually. This includes the death of wild and farmed fish, shellfish and coral reefs; closure of harvestable shellfish and fish stocks; reductions in seafood sales, including it's avoidance, monitoring, impacts on tourism...
Indian Academy of Sciences (India)
An abnormal number of abortions among pigs is an indicator of a potential outbreak in a locality. It does not manifest as a fatal disease by cerebral involvement in all patients. It is estimated that out of 300 infections with the virus only one results in symptomatic illness. Mortality is predominant amo~g children below 14 years.
Liu, Yue; Alexeeva, Svetlana; Defourny, Kyra A.Y.; Smid, Eddy J.; Abee, Tjakko
2018-01-01
Membrane vesicle (MV) production is observed in all domains of life. Evidence of MV production accumulated in recent years among bacterial species involved in fermentation processes. These studies revealed MV composition, biological functions and properties, which made us recognize the potential
Energy Technology Data Exchange (ETDEWEB)
Meisner, L. L., E-mail: llm@ispms.tsc.ru; Meisner, S. N., E-mail: myp@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Markov, A. B., E-mail: a.markov@hq.tsc.ru; Ozur, G. E., E-mail: vrotshtein@yahoo.com; Yakovlev, E. V., E-mail: msn@ispms.tsc.ru [Institute of High Current Electronics SB RAS, Tomsk, 634055 (Russian Federation); Rotshtein, V. P., E-mail: yakovev@lve.hcei.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Tomsk State Pedagogical University, Tomsk, 634050 (Russian Federation); Gudimova, E. Yu., E-mail: ozur@lve.hcei.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)
2015-10-27
The regularities of surface cratering in TiNi alloy irradiated with a low-energy, high-current electron beam (LEHCEB) in dependence on energy density and number of pulses are studied. LEHCEB processing of TiNi samples was carried out using RITM-SP facility. Energy density E{sub s} was varied from 1 to 5 J/cm{sup 2}, pulse duration was 2.5–3.0 μs, the number of pulses n = 1–128. The dominant role of non-metallic inclusions [mainly, TiC(O)] in the nucleation of microcraters was found. It was revealed that at small number of pulses (n = 2), an increase in energy density leads both to increasing average diameter and density of microcraters. An increase in the number of pulses leads to a monotonic decrease in density of microcraters, and, therefore, that of the proportion of the area occupied by microcraters, as well as a decrease in the surface roughness. The multiple LEHCEB melting of TiNi alloy in crater-free modes enables to form quasi-periodical, hierarchically-organized microsized surface structures.
Eves, Howard
1980-01-01
The usefulness of matrix theory as a tool in disciplines ranging from quantum mechanics to psychometrics is widely recognized, and courses in matrix theory are increasingly a standard part of the undergraduate curriculum.This outstanding text offers an unusual introduction to matrix theory at the undergraduate level. Unlike most texts dealing with the topic, which tend to remain on an abstract level, Dr. Eves' book employs a concrete elementary approach, avoiding abstraction until the final chapter. This practical method renders the text especially accessible to students of physics, engineeri
The "Pesticide-exposure Matrix" was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years.
Tendon functional extracellular matrix.
Screen, Hazel R C; Berk, David E; Kadler, Karl E; Ramirez, Francesco; Young, Marian F
2015-06-01
This article is one of a series, summarizing views expressed at the Orthopaedic Research Society New Frontiers in Tendon Research Conference. This particular article reviews the three workshops held under the "Functional Extracellular Matrix" stream. The workshops focused on the roles of the tendon extracellular matrix, such as performing the mechanical functions of tendon, creating the local cell environment, and providing cellular cues. Tendon is a complex network of matrix and cells, and its biological functions are influenced by widely varying extrinsic and intrinsic factors such as age, nutrition, exercise levels, and biomechanics. Consequently, tendon adapts dynamically during development, aging, and injury. The workshop discussions identified research directions associated with understanding cell-matrix interactions to be of prime importance for developing novel strategies to target tendon healing or repair. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.
Bedford, J; Papageorgakis, C.; Rodriguez-Gomez, D.; Ward, J.
2007-01-01
Following the holographic description of linear dilaton null Cosmologies with a Big Bang in terms of Matrix String Theory put forward by Craps, Sethi and Verlinde, we propose an extended background describing a Universe including both Big Bang and Big Crunch singularities. This belongs to a class of exact string backgrounds and is perturbative in the string coupling far away from the singularities, both of which can be resolved using Matrix String Theory. We provide a simple theory capable of...
The Matrix Organization Revisited
DEFF Research Database (Denmark)
Gattiker, Urs E.; Ulhøi, John Parm
1999-01-01
This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively).......This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively)....
DEFF Research Database (Denmark)
Schneider, Jesper Wiborg; Borlund, Pia
2007-01-01
The present two-part article introduces matrix comparison as a formal means for evaluation purposes in informetric studies such as cocitation analysis. In the first part, the motivation behind introducing matrix comparison to informetric studies, as well as two important issues influencing such c...... and Procrustes analysis can be used as statistical validation tools in informetric studies and thus help choosing suitable proximity measures....
Czerwinski, Michael; Spence, Jason R
2017-01-05
Recently in Nature, Gjorevski et al. (2016) describe a fully defined synthetic hydrogel that mimics the extracellular matrix to support in vitro growth of intestinal stem cells and organoids. The hydrogel allows exquisite control over the chemical and physical in vitro niche and enables identification of regulatory properties of the matrix. Copyright © 2017 Elsevier Inc. All rights reserved.
Bhatia, Rajendra
2013-01-01
This book is an outcome of the Indo-French Workshop on Matrix Information Geometries (MIG): Applications in Sensor and Cognitive Systems Engineering, which was held in Ecole Polytechnique and Thales Research and Technology Center, Palaiseau, France, in February 23-25, 2011. The workshop was generously funded by the Indo-French Centre for the Promotion of Advanced Research (IFCPAR). During the event, 22 renowned invited french or indian speakers gave lectures on their areas of expertise within the field of matrix analysis or processing. From these talks, a total of 17 original contribution or state-of-the-art chapters have been assembled in this volume. All articles were thoroughly peer-reviewed and improved, according to the suggestions of the international referees. The 17 contributions presented are organized in three parts: (1) State-of-the-art surveys & original matrix theory work, (2) Advanced matrix theory for radar processing, and (3) Matrix-based signal processing applications.
Pérez López, César
2014-01-01
MATLAB is a high-level language and environment for numerical computation, visualization, and programming. Using MATLAB, you can analyze data, develop algorithms, and create models and applications. The language, tools, and built-in math functions enable you to explore multiple approaches and reach a solution faster than with spreadsheets or traditional programming languages, such as C/C++ or Java. MATLAB Matrix Algebra introduces you to the MATLAB language with practical hands-on instructions and results, allowing you to quickly achieve your goals. Starting with a look at symbolic and numeric variables, with an emphasis on vector and matrix variables, you will go on to examine functions and operations that support vectors and matrices as arguments, including those based on analytic parent functions. Computational methods for finding eigenvalues and eigenvectors of matrices are detailed, leading to various matrix decompositions. Applications such as change of bases, the classification of quadratic forms and ...
DEFF Research Database (Denmark)
Frandsen, Gudmund Skovbjerg; Frandsen, Peter Frands
2009-01-01
We consider maintaining information about the rank of a matrix under changes of the entries. For n×n matrices, we show an upper bound of O(n1.575) arithmetic operations and a lower bound of Ω(n) arithmetic operations per element change. The upper bound is valid when changing up to O(n0.575) entries...... in a single column of the matrix. We also give an algorithm that maintains the rank using O(n2) arithmetic operations per rank one update. These bounds appear to be the first nontrivial bounds for the problem. The upper bounds are valid for arbitrary fields, whereas the lower bound is valid for algebraically...... closed fields. The upper bound for element updates uses fast rectangular matrix multiplication, and the lower bound involves further development of an earlier technique for proving lower bounds for dynamic computation of rational functions....
Energy Technology Data Exchange (ETDEWEB)
Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory
2010-01-01
In the matrix interdiction problem, a real-valued matrix and an integer k is given. The objective is to remove k columns such that the sum over all rows of the maximum entry in each row is minimized. This combinatorial problem is closely related to bipartite network interdiction problem which can be applied to prioritize the border checkpoints in order to minimize the probability that an adversary can successfully cross the border. After introducing the matrix interdiction problem, we will prove the problem is NP-hard, and even NP-hard to approximate with an additive n{gamma} factor for a fixed constant {gamma}. We also present an algorithm for this problem that achieves a factor of (n-k) mUltiplicative approximation ratio.
Matrixed business support comparison study.
Energy Technology Data Exchange (ETDEWEB)
Parsons, Josh D.
2004-11-01
The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.
Hohn, Franz E
2012-01-01
This complete and coherent exposition, complemented by numerous illustrative examples, offers readers a text that can teach by itself. Fully rigorous in its treatment, it offers a mathematically sound sequencing of topics. The work starts with the most basic laws of matrix algebra and progresses to the sweep-out process for obtaining the complete solution of any given system of linear equations - homogeneous or nonhomogeneous - and the role of matrix algebra in the presentation of useful geometric ideas, techniques, and terminology.Other subjects include the complete treatment of the structur
Energy Technology Data Exchange (ETDEWEB)
Brown, T.W.
2010-11-15
The same complex matrix model calculates both tachyon scattering for the c=1 non-critical string at the self-dual radius and certain correlation functions of half-BPS operators in N=4 super- Yang-Mills. It is dual to another complex matrix model where the couplings of the first model are encoded in the Kontsevich-like variables of the second. The duality between the theories is mirrored by the duality of their Feynman diagrams. Analogously to the Hermitian Kontsevich- Penner model, the correlation functions of the second model can be written as sums over discrete points in subspaces of the moduli space of punctured Riemann surfaces. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Galdikas, A. [Department of Physics and Mathematics, Kaunas University of Medicine (Lithuania); Riviere, J.P.; Pichon, L. [Laboratoire de Physique des Materiaux, University of Poitiers, Poitiers (France); Petraitiene, A.; Moskalioviene, T. [Physics Department, Kaunas University of Technology, 50 Studentu st., Kaunas (Lithuania)
2010-11-15
We have analyzed the interfacial elemental depth profile evolution after high temperature isothermal oxidation of NiTi coatings deposited by dynamic ion mixing on a Ti6242 alloy (Ti-6Al-2Sn-4Zr-2Mo). NiTi coatings (thickness 0.4 {mu}m) were deposited at room temperature (RT) by ion beam sputtering. High temperature isothermal oxidation tests in 1 atm flowing synthetic air (80% N{sub 2}, 20% O{sub 2}) have been conducted at 500 C and 600 C during 100 hours. We have observed a non-monotonous depth distribution of nickel in GDOES depth profiles after oxidation of TiNi/Ti6242: nickel segregates to the surface of TiNi coating and to the interface between TiNi coating and Ti6242 alloy. We propose a kinetic model based on rate equations for analyzing the depth profile. This model includes microprocesses taking place during oxidation in air such as: adsorption of nitrogen and oxygen, diffusion of components through the film and interface, formation of chemical compounds. It is shown by modeling that non-monotonous depth profile of nickel occurs because nickel from TiNi coating is forming a nickel oxide compound when oxygen atoms reach the film/alloy interface. XRD analysis confirms the presence of nickel oxide in the TiNi/Ti6242 interface after oxidation at both temperatures 500 C and 600 C (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Energy Technology Data Exchange (ETDEWEB)
Nishida, M.; Itai, I.; Ohgi, H.; Chiba, A. [Kumamoto Univ. (Japan). Dept. of Materials Science and Resource Engineering; Yamauchi, K. [Tokin Corp., Sendai (Japan). Materials Science and Development Lab.
1995-03-01
The boundary structure of the <011> Type II, {l_brace}11{bar 1}{r_brace} Type I, {l_brace}011{r_brace} Type I, (100) compound and (001) compound twins in the B19{prime} martensite in the Ti-Ni shape memory alloy was observed in the edge-on state by high resolution electron microscopy (HREM). The lattice images of the Type I and the compound twins exhibit the well-defined crystallographic features of those boundaries. Lattice image of the <011> Type II twin taken from the unique {eta}{sub 1} axis suggests that neither ledge nor step structures are present at the irrational boundary.
el Bachraoui, M.; van de Vel, M.L.J.
2002-01-01
Square matrices over a relation algebra are relation algebras in a natural way. We show that for fixed n, these algebras can be characterized as reducts of some richer kind of algebra. Hence for fixed n, the class of n × n matrix relation algebras has a first-order characterization. As a
Kernelized Bayesian Matrix Factorization.
Gönen, Mehmet; Kaski, Samuel
2014-10-01
We extend kernelized matrix factorization with a full-Bayesian treatment and with an ability to work with multiple side information sources expressed as different kernels. Kernels have been introduced to integrate side information about the rows and columns, which is necessary for making out-of-matrix predictions. We discuss specifically binary output matrices but extensions to realvalued matrices are straightforward. We extend the state of the art in two key aspects: (i) A full-conjugate probabilistic formulation of the kernelized matrix factorization enables an efficient variational approximation, whereas full-Bayesian treatments are not computationally feasible in the earlier approaches. (ii) Multiple side information sources are included, treated as different kernels in multiple kernel learning which additionally reveals which side sources are informative. We then show that the framework can also be used for supervised and semi-supervised multilabel classification and multi-output regression, by considering samples and outputs as the domains where matrix factorization operates. Our method outperforms alternatives in predicting drug-protein interactions on two data sets. On multilabel classification, our algorithm obtains the lowest Hamming losses on 10 out of 14 data sets compared to five state-of-the-art multilabel classification algorithms. We finally show that the proposed approach outperforms alternatives in multi-output regression experiments on a yeast cell cycle data set.
Indian Academy of Sciences (India)
chaos to galaxies. We demonstrate the applicability of random matrix theory for networks by pro- viding a new dimension to complex systems research. We show that in spite of huge differences ... as mentioned earlier, different types of networks can be constructed based on the nature of connections. For example,.
Elliott, John
2012-09-01
As part of our 'toolkit' for analysing an extraterrestrial signal, the facility for calculating structural affinity to known phenomena must be part of our core capabilities. Without such a resource, we risk compromising our potential for detection and decipherment or at least causing significant delay in the process. To create such a repository for assessing structural affinity, all known systems (language parameters) need to be structurally analysed to 'place' their 'system' within a relational communication matrix. This will need to include all known variants of language structure, whether 'living' (in current use) or ancient; this must also include endeavours to incorporate yet undeciphered scripts and non-human communication, to provide as complete a picture as possible. In creating such a relational matrix, post-detection decipherment will be assisted by a structural 'map' that will have the potential for 'placing' an alien communication with its nearest known 'neighbour', to assist subsequent categorisation of basic parameters as a precursor to decipherment. 'Universal' attributes and behavioural characteristics of known communication structure will form a range of templates (Elliott, 2001 [1] and Elliott et al., 2002 [2]), to support and optimise our attempt at categorising and deciphering the content of an extraterrestrial signal. Detection of the hierarchical layers, which comprise intelligent, complex communication, will then form a matrix of calculations that will ultimately score affinity through a relational matrix of structural comparison. In this paper we develop the rationales and demonstrate functionality with initial test results.
SenStick: Comprehensive Sensing Platform with an Ultra Tiny All-In-One Sensor Board for IoT Research
Directory of Open Access Journals (Sweden)
Yugo Nakamura
2017-01-01
Full Text Available We propose a comprehensive sensing platform called SenStick, which is composed of hardware (ultra tiny all-in-one sensor board, software (iOS, Android, and PC, and 3D case data. The platform aims to allow all the researchers to start IoT research, such as activity recognition and context estimation, easily and efficiently. The most important contribution is the hardware that we have designed. Various sensors often used for research are embedded in an ultra tiny board with the size of 50 mm (W × 10 mm (H × 5 mm (D and weight around 3 g including a battery. Concretely, the following sensors are embedded on this board: acceleration, gyro, magnetic, light, UV, temperature, humidity, and pressure. In addition, this board has BLE (Bluetooth low energy connectivity and capability of a rechargeable battery. By using 110 mAh battery, it can run more than 15 hours. The most different point from other similar boards is that our board has a large flash memory for logging all the data without a smartphone. By using SenStick, all the users can collect various data easily and focus on IoT data analytics. In this paper, we introduce SenStick platform and some case studies. Through the user study, we confirmed the usefulness of our proposed platform.
Matrix groups for undergraduates
Tapp, Kristopher
2016-01-01
Matrix groups touch an enormous spectrum of the mathematical arena. This textbook brings them into the undergraduate curriculum. It makes an excellent one-semester course for students familiar with linear and abstract algebra and prepares them for a graduate course on Lie groups. Matrix Groups for Undergraduates is concrete and example-driven, with geometric motivation and rigorous proofs. The story begins and ends with the rotations of a globe. In between, the author combines rigor and intuition to describe the basic objects of Lie theory: Lie algebras, matrix exponentiation, Lie brackets, maximal tori, homogeneous spaces, and roots. This second edition includes two new chapters that allow for an easier transition to the general theory of Lie groups. From reviews of the First Edition: This book could be used as an excellent textbook for a one semester course at university and it will prepare students for a graduate course on Lie groups, Lie algebras, etc. … The book combines an intuitive style of writing w...
Extracellular matrix structure.
Theocharis, Achilleas D; Skandalis, Spyros S; Gialeli, Chrysostomi; Karamanos, Nikos K
2016-02-01
Extracellular matrix (ECM) is a non-cellular three-dimensional macromolecular network composed of collagens, proteoglycans/glycosaminoglycans, elastin, fibronectin, laminins, and several other glycoproteins. Matrix components bind each other as well as cell adhesion receptors forming a complex network into which cells reside in all tissues and organs. Cell surface receptors transduce signals into cells from ECM, which regulate diverse cellular functions, such as survival, growth, migration, and differentiation, and are vital for maintaining normal homeostasis. ECM is a highly dynamic structural network that continuously undergoes remodeling mediated by several matrix-degrading enzymes during normal and pathological conditions. Deregulation of ECM composition and structure is associated with the development and progression of several pathologic conditions. This article emphasizes in the complex ECM structure as to provide a better understanding of its dynamic structural and functional multipotency. Where relevant, the implication of the various families of ECM macromolecules in health and disease is also presented. Copyright © 2015 Elsevier B.V. All rights reserved.
A note on matrix differentiation
Kowal, Pawel
2006-01-01
This paper presents a set of rules for matrix differentiation with respect to a vector of parameters, using the flattered representation of derivatives, i.e. in form of a matrix. We also introduce a new set of Kronecker tensor products of matrices. Finally we consider a problem of differentiating matrix determinant, trace and inverse.
The cellulose resource matrix.
Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G
2013-03-01
The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the
Deift, Percy
2009-01-01
This book features a unified derivation of the mathematical theory of the three classical types of invariant random matrix ensembles-orthogonal, unitary, and symplectic. The authors follow the approach of Tracy and Widom, but the exposition here contains a substantial amount of additional material, in particular, facts from functional analysis and the theory of Pfaffians. The main result in the book is a proof of universality for orthogonal and symplectic ensembles corresponding to generalized Gaussian type weights following the authors' prior work. New, quantitative error estimates are derive
Directory of Open Access Journals (Sweden)
Abdelhakim Chillali
2017-05-01
Full Text Available In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra. In this work, we proposed a new problem applicable to the public key cryptography, based on the Matrices, called “Matrix discrete logarithm problem”, it uses certain elements formed by matrices whose coefficients are elements in a finite field. We have constructed an abelian group and, for the cryptographic part in this unreliable group, we then perform the computation corresponding to the algebraic equations, Returning the encrypted result to a receiver. Upon receipt of the result, the receiver can retrieve the sender’s clear message by performing the inverse calculation.
Matrix string partition function
Kostov, Ivan K; Kostov, Ivan K.; Vanhove, Pierre
1998-01-01
We evaluate quasiclassically the Ramond partition function of Euclidean D=10 U(N) super Yang-Mills theory reduced to a two-dimensional torus. The result can be interpreted in terms of free strings wrapping the space-time torus, as expected from the point of view of Matrix string theory. We demonstrate that, when extrapolated to the ultraviolet limit (small area of the torus), the quasiclassical expressions reproduce exactly the recently obtained expression for the partition of the completely reduced SYM theory, including the overall numerical factor. This is an evidence that our quasiclassical calculation might be exact.
Eisenman, Richard L
2005-01-01
This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur
Matrix algebra for linear models
Gruber, Marvin H J
2013-01-01
Matrix methods have evolved from a tool for expressing statistical problems to an indispensable part of the development, understanding, and use of various types of complex statistical analyses. This evolution has made matrix methods a vital part of statistical education. Traditionally, matrix methods are taught in courses on everything from regression analysis to stochastic processes, thus creating a fractured view of the topic. Matrix Algebra for Linear Models offers readers a unique, unified view of matrix analysis theory (where and when necessary), methods, and their applications. Written f
Ramachandran, Balakrishnan; Chang, Pei-Chi; Kuo, Yung-Kang; Chien, Chen; Wu, Shyi-Kaan
2017-11-27
The electrical resistivity, Seebeck coefficient, thermal conductivity, and specific heat of Ti50Ni50-x Fe x (x = 2.0-10.0 at.%) shape memory alloys (SMAs) were measured to investigate the influence of point defects (Fe) on the martensitic transformation characteristics. Our results show that the Ti50Ni48Fe2 and Ti50Ni47Fe3 SMAs have a two-step martensitic transformation (B2 → R and R → B19'), while the Ti50Ni46Fe4, Ti50Ni44.5Fe5.5, and Ti50Ni44Fe6 SMAs display a one-step martensitic transition (B2 → R). However, the compounds Ti50Ni42Fe8 and Ti50Ni40Fe10 show strain glass features (frozen strain-ordered state). Importantly, the induced point defects significantly alter the martensitic transformation characteristics, namely transition temperature and width of thermal hysteresis during the transition. This can be explained by the stabilization of austenite B2 phase upon Fe substitution, which ultimately leads to the decrease in enthalpy that associated to the martensitic transition. To determine the boundary composition that separates the R-phase and strain glass systems in this series of SMAs, a Ni-rich specimen Ti49Ni45Fe6 was fabricated. Remarkably, a slight change in Ti/Ni ratio converts Ti49Ni45Fe6 SMA into a strain glass system. Overall, the evolution of phase transformation in the Fe-substituted TiNi SMAs is presumably caused by the changes in local lattice structure via the induced local strain fields by Fe point defects.
Su, Yuxi; Nan, Guoxin
2016-05-01
Embedment of metallic foreign bodies in the soft tissues is commonly encountered in the emergency room. Most foreign bodies are easily removed, but removal is difficult if the foreign body is very small or deeply embedded. To determine the usefulness of methylene blue staining in the surgical removal of tiny metallic foreign bodies embedded in the soft tissue. This prospective study involved 41 children treated between May 2007 and May 2012. The patients were randomly divided into a methylene blue group and a control group. In the control group, foreign bodies were located using a C-arm and removed via direct incision. In the methylene blue group, foreign bodies were located using a C-arm, marked with an injection of methylene blue and then removed surgically. The clinical outcomes, complications, operation time, surgical success rate, incision length, frequency of C-arm use, and length and depth of the foreign body were compared between the two groups. The surgical success rate was significantly higher in the methylene blue group. The average operation time was significantly shorter in the methylene blue group. The C-arm was used significantly less frequently in the methylene blue group than in the control group. The incision length was significantly shorter in the methylene blue group than in the control group. Methylene blue staining facilitated the location and removal of tiny metallic foreign bodies from the soft tissue, and significantly reduced operation time, incision length and radiation exposure compared to the conventional method. Copyright © 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.
Shaw, Alexandra P. M.; Tirados, Inaki; Mangwiro, Clement T. N.; Esterhuizen, Johan; Lehane, Michael J.; Torr, Stephen J.; Kovacic, Vanja
2015-01-01
Introduction To evaluate the relative effectiveness of tsetse control methods, their costs need to be analysed alongside their impact on tsetse populations. Very little has been published on the costs of methods specifically targeting human African trypanosomiasis Methodology/Principal Findings In northern Uganda, a 250 km2 field trial was undertaken using small (0.5 X 0.25 m) insecticide-treated targets (“tiny targets”). Detailed cost recording accompanied every phase of the work. Costs were calculated for this operation as if managed by the Ugandan vector control services: removing purely research components of the work and applying local salaries. This calculation assumed that all resources are fully used, with no spare capacity. The full cost of the operation was assessed at USD 85.4 per km2, of which USD 55.7 or 65.2% were field costs, made up of three component activities (target deployment: 34.5%, trap monitoring: 10.6% and target maintenance: 20.1%). The remaining USD 29.7 or 34.8% of the costs were for preliminary studies and administration (tsetse surveys: 6.0%, sensitisation of local populations: 18.6% and office support: 10.2%). Targets accounted for only 12.9% of the total cost, other important cost components were labour (24.1%) and transport (34.6%). Discussion Comparison with the updated cost of historical HAT vector control projects and recent estimates indicates that this work represents a major reduction in cost levels. This is attributed not just to the low unit cost of tiny targets but also to the organisation of delivery, using local labour with bicycles or motorcycles. Sensitivity analyses were undertaken, investigating key prices and assumptions. It is believed that these costs are generalizable to other HAT foci, although in more remote areas, with denser vegetation and fewer people, costs would increase, as would be the case for other tsetse control techniques. PMID:25811956
Ceramic matrix and resin matrix composites: A comparison
Hurwitz, Frances I.
1987-01-01
The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.
Ceramic matrix and resin matrix composites - A comparison
Hurwitz, Frances I.
1987-01-01
The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.
Frahm, K. M.; Shepelyansky, D. L.
2012-10-01
We construct the Google matrix of the entire Twitter network, dated by July 2009, and analyze its spectrum and eigenstate properties including the PageRank and CheiRank vectors and 2DRanking of all nodes. Our studies show much stronger inter-connectivity between top PageRank nodes for the Twitter network compared to the networks of Wikipedia and British Universities studied previously. Our analysis allows to locate the top Twitter users which control the information flow on the network. We argue that this small fraction of the whole number of users, which can be viewed as the social network elite, plays the dominant role in the process of opinion formation on the network.
Matrix membranes and integrability
Energy Technology Data Exchange (ETDEWEB)
Zachos, C. [Argonne National Lab., IL (United States); Fairlie, D. [University of Durham (United Kingdom). Dept. of Mathematical Sciences; Curtright, T. [University of Miami, Coral Gables, FL (United States). Dept. of Physics
1997-06-01
This is a pedagogical digest of results reported in Curtright, Fairlie, {ampersand} Zachos 1997, and an explicit implementation of Euler`s construction for the solution of the Poisson Bracket dual Nahm equation. But it does not cover 9 and 10-dimensional systems, and subsequent progress on them Fairlie 1997. Cubic interactions are considered in 3 and 7 space dimensions, respectively, for bosonic membranes in Poisson Bracket form. Their symmetries and vacuum configurations are explored. Their associated first order equations are transformed to Nahm`s equations, and are hence seen to be integrable, for the 3-dimensional case, by virtue of the explicit Lax pair provided. Most constructions introduced also apply to matrix commutator or Moyal Bracket analogs.
Energy Technology Data Exchange (ETDEWEB)
Hastings, Matthew B [Los Alamos National Laboratory
2009-01-01
We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.
Andric, I; Jurman, D; Nielsen, H B
2007-01-01
We discuss a dynamical matrix model by which probability distribution is associated with Gaussian ensembles from random matrix theory. We interpret the matrix M as a Hamiltonian representing interaction of a bosonic system with a single fermion. We show that a system of second-quantized fermions influences the ground state of the whole system by producing a gap between the highest occupied eigenvalue and the lowest unoccupied eigenvalue.
Verwei, M.; Minekus, M.; Zeijdner, E.; Schilderink, R.; Havenaar, R.
2016-01-01
Pharmaceutical research needs predictive in vitro tools for API bioavailability in humans. We evaluated two dynamic in vitro gastrointestinal models: TIM-1 and tiny-TIM. Four low-soluble APIs in various formulations were investigated in the TIM systems under fasted and fed conditions. API
Matrix Depot: an extensible test matrix collection for Julia
Directory of Open Access Journals (Sweden)
Weijian Zhang
2016-04-01
Full Text Available Matrix Depot is a Julia software package that provides easy access to a large and diverse collection of test matrices. Its novelty is threefold. First, it is extensible by the user, and so can be adapted to include the user’s own test problems. In doing so, it facilitates experimentation and makes it easier to carry out reproducible research. Second, it amalgamates in a single framework two different types of existing matrix collections, comprising parametrized test matrices (including Hansen’s set of regularization test problems and Higham’s Test Matrix Toolbox and real-life sparse matrix data (giving access to the University of Florida sparse matrix collection. Third, it fully exploits the Julia language. It uses multiple dispatch to help provide a simple interface and, in particular, to allow matrices to be generated in any of the numeric data types supported by the language.
Ceramic matrix composite article and process of fabricating a ceramic matrix composite article
Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert
2016-01-12
A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.
An Application of Matrix Multiplication
Indian Academy of Sciences (India)
IAS Admin
linguistics, graph theory applications to biological networks, social networks, electrical engineering. We are well aware of the ever increasing impor- tance of graphical and matrix representations in applications to several day-to-day real life prob- lems. The interconnectedness of the notion of graph, matrix, probability, limits, ...
Matrix Methods to Analytic Geometry.
Bandy, C.
1982-01-01
The use of basis matrix methods to rotate axes is detailed. It is felt that persons who have need to rotate axes often will find that the matrix method saves considerable work. One drawback is that most students first learning to rotate axes will not yet have studied linear algebra. (MP)
Jairam, Dharmananda; Kiewra, Kenneth A.; Kauffman, Douglas F.; Zhao, Ruomeng
2012-01-01
This study investigated how best to study a matrix. Fifty-three participants studied a matrix topically (1 column at a time), categorically (1 row at a time), or in a unified way (all at once). Results revealed that categorical and unified study produced higher: (a) performance on relationship and fact tests, (b) study material satisfaction, and…
Developments in Random Matrix Theory
Snaith, N. C.; Forrester, P. J.; Verbaarschot, J. J. M.
2003-01-01
In this preface to the Journal of Physics A, Special Edition on Random Matrix Theory, we give a review of the main historical developments of random matrix theory. A short summary of the papers that appear in this special edition is also given.
Energy Technology Data Exchange (ETDEWEB)
Jackson, A.D. [Niels Bohr Inst., Copenhagen (Denmark)
1998-08-10
Chiral random matrix theory has recently been shown to provide a tool useful for both modeling chiral symmetry restoration in QCD and for providing analytic descriptions of the microscopic spectral content of lattice gauge simulations. The basic ideas of chiral random matrix theory and some recent results are discussed. (orig.) 24 refs.
Quantum mechanics in matrix form
Ludyk, Günter
2018-01-01
This book gives an introduction to quantum mechanics with the matrix method. Heisenberg's matrix mechanics is described in detail. The fundamental equations are derived by algebraic methods using matrix calculus. Only a brief description of Schrödinger's wave mechanics is given (in most books exclusively treated), to show their equivalence to Heisenberg's matrix method. In the first part the historical development of Quantum theory by Planck, Bohr and Sommerfeld is sketched, followed by the ideas and methods of Heisenberg, Born and Jordan. Then Pauli's spin and exclusion principles are treated. Pauli's exclusion principle leads to the structure of atoms. Finally, Dirac´s relativistic quantum mechanics is shortly presented. Matrices and matrix equations are today easy to handle when implementing numerical algorithms using standard software as MAPLE and Mathematica.
Machining of Metal Matrix Composites
2012-01-01
Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...
Assembly of Fibronectin Extracellular Matrix
Singh, Purva; Carraher, Cara; Schwarzbauer, Jean E.
2013-01-01
In the process of matrix assembly, multivalent extracellular matrix (ECM) proteins are induced to self-associate and to interact with other ECM proteins to form fibrillar networks. Matrix assembly is usually initiated by ECM glycoproteins binding to cell surface receptors, such as fibronectin (FN) dimers binding to α5β1 integrin. Receptor binding stimulates FN self-association mediated by the N-terminal assembly domain and organizes the actin cytoskeleton to promote cell contractility. FN conformational changes expose additional binding sites that participate in fibril formation and in conversion of fibrils into a stabilized, insoluble form. Once assembled, the FN matrix impacts tissue organization by contributing to the assembly of other ECM proteins. Here, we describe the major steps, molecular interactions, and cellular mechanisms involved in assembling FN dimers into fibrillar matrix while highlighting important issues and major questions that require further investigation. PMID:20690820
Porter, Susannah M
2016-05-25
One explanation for the Early Neoproterozoic expansion of eukaryotes is the appearance of eukaryovorous predators-i.e. protists that preyed on other protists. Evidence for eukaryovory at this time, however, is indirect, based on inferences from character state reconstructions and molecular clocks, and on the presence of possible defensive structures in some protistan fossils. Here I describe 0.1-3.4 µm circular holes in seven species of organic-walled microfossils from the 780-740 million-year-old Chuar Group, Grand Canyon, Arizona, USA, that are similar to those formed today by predatory protists that perforate the walls of their prey to consume the contents inside. Although best known in the vampyrellid amoebae, this 'vampire-like' behaviour is widespread among eukaryotes, making it difficult to infer confidently the identity of the predator. Nonetheless, the identity of the prey is clear: some-and perhaps all-of the fossils are eukaryotes. These holes thus provide the oldest direct evidence for predation on eukaryotes. Larger circular and half-moon-shaped holes in vase-shaped microfossils from the upper part of the unit may also be the work of 'tiny vampires', suggesting a diversity of eukaryovorous predators lived in the ancient Chuar sea. © 2016 The Author(s).
2016-01-01
One explanation for the Early Neoproterozoic expansion of eukaryotes is the appearance of eukaryovorous predators—i.e. protists that preyed on other protists. Evidence for eukaryovory at this time, however, is indirect, based on inferences from character state reconstructions and molecular clocks, and on the presence of possible defensive structures in some protistan fossils. Here I describe 0.1–3.4 µm circular holes in seven species of organic-walled microfossils from the 780–740 million-year-old Chuar Group, Grand Canyon, Arizona, USA, that are similar to those formed today by predatory protists that perforate the walls of their prey to consume the contents inside. Although best known in the vampyrellid amoebae, this ‘vampire-like’ behaviour is widespread among eukaryotes, making it difficult to infer confidently the identity of the predator. Nonetheless, the identity of the prey is clear: some—and perhaps all—of the fossils are eukaryotes. These holes thus provide the oldest direct evidence for predation on eukaryotes. Larger circular and half-moon-shaped holes in vase-shaped microfossils from the upper part of the unit may also be the work of ‘tiny vampires’, suggesting a diversity of eukaryovorous predators lived in the ancient Chuar sea. PMID:27194696
Energy Technology Data Exchange (ETDEWEB)
Kim, Seung Soo [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea, Republic of); Cheonan Hospital, Department of Radiology, Soonchunhyang University College of Medicine, Cheonan-si, Chungcheongnam-do (Korea, Republic of); Song, Kyoung Doo; Kim, Young Kon [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea, Republic of); Kim, Hee Cheol; Huh, Jung Wook [Sungkyunkwan University School of Medicine, Department of Surgery, Samsung Medical Center, Seoul (Korea, Republic of); Park, Young Suk; Park, Joon Oh; Kim, Seung Tae [Sungkyunkwan University School of Medicine, Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Seoul (Korea, Republic of)
2017-07-15
To evaluate the clinical course of disappearing colorectal liver metastases (DLM) or residual tiny (≤5 mm) colorectal liver metastases (RTCLM) on gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in patients who had colorectal liver metastases (CLM) and received chemotherapy. Among 137 patients who received chemotherapy for CLM and underwent gadoxetic acid-enhanced MRI and DWI between 2010 and 2012, 43 patients with 168 DLMs and 48 RTCLMs were included. The cumulative in situ recurrence rate of DLM and progression rate of RTCLM and their predictive factors were evaluated. A total of 150 DLMs and 26 RTCLMs were followed up without additional treatment. At 1 and 2 years, respectively, the cumulative in situ recurrence rates for DLM were 10.9 % and 15.7 % and the cumulative progression rates for RTCLM were 27.2 % and 33.2 %. The in situ recurrence rate at 2 years was 4.9 % for the DLM group that did not show reticular hypointensity of liver parenchyma on hepatobiliary phase. DLM on gadoxetic acid-enhanced liver MRI and DWI indicates a high possibility of clinical complete response, especially in patients without chemotherapy-induced sinusoidal obstruction syndrome. Thirty-three percent of RTCLMs showed progression at 2 years. (orig.)
New pole placement algorithm - Polynomial matrix approach
Shafai, B.; Keel, L. H.
1990-01-01
A simple and direct pole-placement algorithm is introduced for dynamical systems having a block companion matrix A. The algorithm utilizes well-established properties of matrix polynomials. Pole placement is achieved by appropriately assigning coefficient matrices of the corresponding matrix polynomial. This involves only matrix additions and multiplications without requiring matrix inversion. A numerical example is given for the purpose of illustration.
[Progress on matrix metalloproteinase inhibitors].
Lingling, Jia; Qianbing, Wan
2017-04-01
Continuing advances in dentin bonding technology and adhesives revolutionized bonding of resin-based composite restorations. However, hybrid layers created by contemporary dentin adhesives present imperfect durability, and degradation of collagen matrix by endogenous enzymes is a significant factor causing destruction of hybrid layers. Bond durability can be improved by using enzyme inhibitors to prevent collagen degradation and to preserve integrity of collagen matrix. This review summarizes progress on matrix metalloproteinase inhibitors (including chlorhexidine, ethylenediaminetetraacetic acid, quaternary ammonium salt, tetracycline and its derivatives, hydroxamic acid inhibitors, bisphosphonate derivative, and cross-linking agents) and suggests prospects for these compounds.
Hadronic matrix elements for Kaons
Energy Technology Data Exchange (ETDEWEB)
Bijnens, Johan [Department of Theoretical Physics 2, Lund University, Soelvegatan 14A, S-22362 Lund (Sweden); Gamiz, Elvira [CAFPE and Departamento de Fisica Teorica y del Cosmos, Universidad de Granada Campus de Fuente Nueva, E-18002 Granada (Spain); Prades, Joaquim [CAFPE and Departamento de Fisica Teorica y del Cosmos, Universidad de Granada Campus de Fuente Nueva, E-18002 Granada (Spain)
2004-07-01
We review some work done by us calculating matrix elements for Kaons. Emphasis is put on the matrix elements which are relevant to predict non-leptonic Kaon CP violating observables. In particular, we recall our results for the B{sub K} parameter which governs the K{sup 0}-K{sup 0} mixing and update our results for {epsilon}'inK including estimated all-higher-order CHPT corrections and the new results from recent analytical calculations of the {delta}itI = 3/2 component. Some comments on future prospects on calculating matrix elements for Kaons are also added.
Directory of Open Access Journals (Sweden)
Zhaolin Liu
2012-08-01
Full Text Available Assimilating hydrophilic hollow polymer spheres (HPS into Nafion matrix by a loading of 0.5 wt % led to a restructured hydrophilic channel, composed of the pendant sulfonic acid groups (–SO_{3}H and the imbedded hydrophilic hollow spheres. The tiny hydrophilic hollow chamber was critical to retaining moisture and facilitating proton transfer in the composite membranes. To obtain such a tiny cavity structure, the synthesis included selective generation of a hydrophilic polymer shell on silica microsphere template and the subsequent removal of the template by etching. The hydrophilic HPS (100–200 nm possessed two different spherical shells, the styrenic network with pendant sulfonic acid groups and with methacrylic acid groups, respectively. By behaving as microreservoirs of water, the hydrophilic HPS promoted the Grotthus mechanism and, hence, enhanced proton transport efficiency through the inter-sphere path. In addition, the HPS with the –SO_{3}H borne shell played a more effective role than those with the –CO_{2}H borne shell in augmenting proton transport, in particular under low humidity or at medium temperatures. Single H_{2}-PEMFC test at 70^{ }°C using dry H_{2}/O_{2} further verified the impactful role of hydrophilic HPS in sustaining higher proton flux as compared to pristine Nafion membrane.
A novel approach for FE-SEM imaging of wood-matrix polymer interface in a biocomposite.
Singh, Adya P; Anderson, Ross; Park, Byung-Dae; Nuryawan, Arif
2013-01-01
Understanding the interface between polymer and biomass in composite products is important for developing high performance products, as the quality of adhesion at the interface determines composite properties. For example, with greater stiffness compared to polymer matrix, such as that of high density polyethylene, the wood component enhances stiffness of wood-polymer composites, provided there is good adhesion between composite components. However, in composites made from wood flour (wood particles) and synthetic resins it is often difficult to clearly resolve particle-matrix interfaces in the conventionally employed microscopy method that involves SEM examination of fractured faces of composites. We developed a novel approach, where composites made from high density polyethylene and wood flour were examined and imaged with a FE-SEM (field emission scanning electron microscope) in transverse sections cut through the composites. Improved definition of the interface was achieved using this approach, which enabled a more thorough comparison to be made of the features of the interface between wood particles and the matrix in composites with and without a coupling agent, as it was possible to clearly resolve the interfaces for particles of all sizes, from large particles consisting of many cells down to tiny cell wall fragments, particularly in composites that did not incorporate the coupling agent used to enhance particle adhesion with the matrix polymer. The method developed would be suitable particularly for high definition SEM imaging of a wide range of composites made combining wood and agricultural residues with synthetic polymers. Copyright © 2013 Elsevier Ltd. All rights reserved.
National Oceanic and Atmospheric Administration, Department of Commerce — This data set was taken from CRD 08-18 at the NEFSC. Specifically, the Gulf of Maine diet matrix was developed for the EMAX exercise described in that center...
Álvarez, Enrique; Meessen, Patrick
1998-05-01
A Newtonian matrix cosmology, corresponding to the Banks, Fischler, Shenker and Susskind model of eleven-dimensional M-theory in the infinite momentum frame as a supersymmetric (0+1) M(atrix) model is constructed. Interesting new results are obtained, such as the existence of (much sought for in the past) static solutions. The possible interpretation of the off-diagonal entries as a background geometry is also briefly discussed.
Superstatistics in Random Matrix Theory
Abul-Magd, A. Y.
2011-01-01
Random matrix theory (RMT) provides a successful model for quantum systems, whose classical counterpart has a chaotic dynamics. It is based on two assumptions: (1) matrix-element independence, and (2) base invariance. Last decade witnessed several attempts to extend RMT to describe quantum systems with mixed regular-chaotic dynamics. Most of the proposed generalizations keep the first assumption and violate the second. Recently, several authors presented other versions of the theory that keep...
Matrix analysis of electrical machinery
Hancock, N N
2013-01-01
Matrix Analysis of Electrical Machinery, Second Edition is a 14-chapter edition that covers the systematic analysis of electrical machinery performance. This edition discusses the principles of various mathematical operations and their application to electrical machinery performance calculations. The introductory chapters deal with the matrix representation of algebraic equations and their application to static electrical networks. The following chapters describe the fundamentals of different transformers and rotating machines and present torque analysis in terms of the currents based on the p
Qin, Mingpu; Zhang, Shiwei
2016-01-01
The vast majority of quantum Monte Carlo (QMC) calculations in interacting fermion systems require a constraint to control the sign problem. The constraint involves an input trial wave function which restricts the random walks. We introduce a systematically improvable constraint which relies on the fundamental role of the density or one-body density matrix. An independent-particle calculation is coupled to an auxiliary-field QMC calculation. The independent-particle solution is used as the constraint in QMC, which then produces the input density or density matrix for the next iteration. The constraint is optimized by the self-consistency between the many-body and independent-particle calculations. The approach is demonstrated in the two-dimensional Hubbard model by accurately determining the spin densities when collective modes separated by tiny energy scales are present in the magnetic and charge correlations. Our approach also provides an ab initio way to predict effective "U" parameters for independent-par...
Zhang, Chun-Hong; Zhu, Jian; Li, Jian-Jun; Zhao, Jun-Wu
2017-05-24
The great harm of thiram residue in soil to environment and human health is usually ignored. Due to the complexity of soil compositions, the detection of thiram residue in soil faces considerable difficulties. In this work, a highly sensitive and selective surface-enhanced Raman scattering (SERS) substrate based on the triangular silver nanoplates (TSNPs) with small size and sharp corners is developed and used for the detection of thiram residue in soil for the first time. These TSNPs are synthesized by replacing the conventional seeds in the seed-mediated chemical reduction route with the tiny and uniform triangular silver nuclei (TSN) which can provide more growing space for generating sharp corners during the growth of TSNPs. It is interesting that the TSNPs with the smaller size have the better SERS performance. The possible mechanism behind this phenomenon is explained by the electromagnetic enhancement theory. On the basis of the Raman activity of the smallest TSNPs, a SERS-active substrate is prepared for detecting the thiram residue in soil. The thiram solution detection shows that the limit of detection (LOD) of these smallest TSNPs is lower than other nanoparticles, such as nanospheres, nanocubes, etc. For sensing the thiram residue in soil, the addition of poly(sodium 4-styrenesulfonate) realizes the specific adsorption of thiram by TSNPs. This method exhibits a good linear response from 0.12 to 4.8 μg/g with a low LOD of 90 ng/g, which is better than conventional methods. This work shows the great potential of the small TSNPs as a novel SERS substrate and its broader applications in pesticides detection.
Zhao, Qin; Xu, Jing; Yin, Jia; Feng, Yu-Qi
2015-08-19
In the present study, humic acids (HAs) were applied as both a matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and an adsorbent of magnetic solid phase extraction (MSPE) for the first time. As natural macromolecule compounds, HAs are inherently highly functionalized and contain laser energy absorbing-transferring aromatic structures. This special molecular structure made HAs a good candidate for use as a MALDI matrix in small molecule analysis. At the same time, due to its good adsorption ability, HAs was prepared as MSPE adsorbent via a simple co-mixing method, in which the commercially available HAs were directly mixed with Fe3O4 magnetic nanoparticles (MNPs) in a mortar and grinded evenly and completely. In this process, MNPs were physically wrapped and adhered to tiny HAs leading to the formation of magnetic HAs (MHAs). To verify the bi-function of the MHAs, Rhodamine B (RdB) was chosen as model compound. Our results show that the combination of MHAs-based MSPE and MALDI-TOF-MS can provide a rapid and sensitive method for the determination of RdB in chili oil. The whole analytical procedure could be completed within 30 min for simultaneous determination of more than 20 samples, and the limit of quantitation for RdB was found to be 0.02 μg/g. The recoveries in chili oil were in the range 73.8-81.5% with the RSDs less than 21.3% (intraday) and 20.3% (interday). The proposed strategy has potential applications for high-throughput analysis of small molecules in complex samples. Copyright © 2015 Elsevier B.V. All rights reserved.
Matrix factorizations and elliptic fibrations
Directory of Open Access Journals (Sweden)
Harun Omer
2016-09-01
Full Text Available I use matrix factorizations to describe branes at simple singularities of elliptic fibrations. Each node of the corresponding Dynkin diagrams of the ADE-type singularities is associated with one indecomposable matrix factorization which can be deformed into one or more factorizations of lower rank. Branes with internal fluxes arise naturally as bound states of the indecomposable factorizations. Describing branes in such a way avoids the need to resolve singularities. This paper looks at gauge group breaking from E8 fibers down to SU(5 fibers due to the relevance of such fibrations for local F-theory GUT models. A purpose of this paper is to understand how the deformations of the singularity are understood in terms of its matrix factorizations. By systematically factorizing the elliptic fiber equation, this paper discusses geometries which are relevant for building semi-realistic local models. In the process it becomes evident that breaking patterns which are identical at the level of the Kodaira type of the fibers can be inequivalent at the level of matrix factorizations. Therefore the matrix factorization picture supplements information which the conventional less detailed descriptions lack.
Lectures on matrix field theory
Ydri, Badis
2017-01-01
These lecture notes provide a systematic introduction to matrix models of quantum field theories with non-commutative and fuzzy geometries. The book initially focuses on the matrix formulation of non-commutative and fuzzy spaces, followed by a description of the non-perturbative treatment of the corresponding field theories. As an example, the phase structure of non-commutative phi-four theory is treated in great detail, with a separate chapter on the multitrace approach. The last chapter offers a general introduction to non-commutative gauge theories, while two appendices round out the text. Primarily written as a self-study guide for postgraduate students – with the aim of pedagogically introducing them to key analytical and numerical tools, as well as useful physical models in applications – these lecture notes will also benefit experienced researchers by providing a reference guide to the fundamentals of non-commutative field theory with an emphasis on matrix models and fuzzy geometries.
Matrix formalism of synchrobetatron coupling
Directory of Open Access Journals (Sweden)
Xiaobiao Huang
2007-01-01
Full Text Available In this paper we present a complete linear synchrobetatron coupling formalism by studying the transfer matrix which describes linear horizontal and longitudinal motions. With the technique established in the linear horizontal-vertical coupling study [D. Sagan and D. Rubin, Phys. Rev. ST Accel. Beams 2, 074001 (1999PRABFM1098-440210.1103/PhysRevSTAB.2.074001], we found a transformation to block diagonalize the transfer matrix and decouple the betatron motion and the synchrotron motion. By separating the usual dispersion term from the horizontal coordinate first, we were able to obtain analytic expressions of the transformation under reasonable approximations. We also obtained the perturbations to the betatron tune and the Courant-Snyder functions. The closed-orbit changes due to finite energy gains at rf cavities and radiation energy losses were studied by the 5×5 extended transfer matrix with the fifth column describing kicks in the 4-dimension phase space.
Supersymmetry in random matrix theory
Energy Technology Data Exchange (ETDEWEB)
Kieburg, Mario
2010-05-04
I study the applications of supersymmetry in random matrix theory. I generalize the supersymmetry method and develop three new approaches to calculate eigenvalue correlation functions. These correlation functions are averages over ratios of characteristic polynomials. In the first part of this thesis, I derive a relation between integrals over anti-commuting variables (Grassmann variables) and differential operators with respect to commuting variables. With this relation I rederive Cauchy- like integral theorems. As a new application I trace the supermatrix Bessel function back to a product of two ordinary matrix Bessel functions. In the second part, I apply the generalized Hubbard-Stratonovich transformation to arbitrary rotation invariant ensembles of real symmetric and Hermitian self-dual matrices. This extends the approach for unitarily rotation invariant matrix ensembles. For the k-point correlation functions I derive supersymmetric integral expressions in a unifying way. I prove the equivalence between the generalized Hubbard-Stratonovich transformation and the superbosonization formula. Moreover, I develop an alternative mapping from ordinary space to superspace. After comparing the results of this approach with the other two supersymmetry methods, I obtain explicit functional expressions for the probability densities in superspace. If the probability density of the matrix ensemble factorizes, then the generating functions exhibit determinantal and Pfaffian structures. For some matrix ensembles this was already shown with help of other approaches. I show that these structures appear by a purely algebraic manipulation. In this new approach I use structures naturally appearing in superspace. I derive determinantal and Pfaffian structures for three types of integrals without actually mapping onto superspace. These three types of integrals are quite general and, thus, they are applicable to a broad class of matrix ensembles. (orig.)
Symmetries and Interactions in Matrix String Theory
Hacquebord, F.H.
1999-01-01
This PhD-thesis reviews matrix string theory and recent developments therein. The emphasis is put on symmetries, interactions and scattering processes in the matrix model. We start with an introduction to matrix string theory and a review of the orbifold model that flows out of matrix string theory
Steerneman, A.G.M.; van Perlo -ten Kleij, Frederieke
2005-01-01
The main topic of this paper is the matrix V = A - XY*, where A is a nonsingular complex k x k matrix and X and Y are k x p complex matrices of full column rank. Because properties of the matrix V can be derived from those of the matrix Q = I - XY*, we will consider in particular the case where A =
Polychoric/Tetrachoric Matrix or Pearson Matrix? A methodological study
Directory of Open Access Journals (Sweden)
Dominguez Lara, Sergio Alexis
2014-04-01
Full Text Available The use of product-moment correlation of Pearson is common in most studies in factor analysis in psychology, but it is known that this statistic is only applicable when the variables related are in interval scale and normally distributed, and when are used in ordinal data may to produce a distorted correlation matrix . Thus is a suitable option using polychoric/tetrachoric matrices in item-level factor analysis when the items are in level measurement nominal or ordinal. The aim of this study was to show the differences in the KMO, Bartlett`s Test and Determinant of the Matrix, percentage of variance explained and factor loadings in depression trait scale of Depression Inventory Trait - State and the Neuroticism dimension of the short form of the Eysenck Personality Questionnaire -Revised, regarding the use of matrices polychoric/tetrachoric matrices and Pearson. These instruments was analyzed with different extraction methods (Maximum Likelihood, Minimum Rank Factor Analysis, Unweighted Least Squares and Principal Components, keeping constant the rotation method Promin were analyzed. Were observed differences regarding sample adequacy measures, as well as with respect to the explained variance and the factor loadings, for solutions having as polychoric/tetrachoric matrix. So it can be concluded that the polychoric / tetrachoric matrix give better results than Pearson matrices when it comes to item-level factor analysis using different methods.
Towards Google matrix of brain
Energy Technology Data Exchange (ETDEWEB)
Shepelyansky, D.L., E-mail: dima@irsamc.ups-tlse.f [Laboratoire de Physique Theorique (IRSAMC), Universite de Toulouse, UPS, F-31062 Toulouse (France); LPT - IRSAMC, CNRS, F-31062 Toulouse (France); Zhirov, O.V. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation)
2010-07-12
We apply the approach of the Google matrix, used in computer science and World Wide Web, to description of properties of neuronal networks. The Google matrix G is constructed on the basis of neuronal network of a brain model discussed in PNAS 105 (2008) 3593. We show that the spectrum of eigenvalues of G has a gapless structure with long living relaxation modes. The PageRank of the network becomes delocalized for certain values of the Google damping factor {alpha}. The properties of other eigenstates are also analyzed. We discuss further parallels and similarities between the World Wide Web and neuronal networks.
Random matrix theory and multivariate statistics
Diaz-Garcia, Jose A.; Jáimez, Ramon Gutiérrez
2009-01-01
Some tools and ideas are interchanged between random matrix theory and multivariate statistics. In the context of the random matrix theory, classes of spherical and generalised Wishart random matrix ensemble, containing as particular cases the classical random matrix ensembles, are proposed. Some properties of these classes of ensemble are analysed. In addition, the random matrix ensemble approach is extended and a unified theory proposed for the study of distributions for real normed divisio...
Matrix theory selected topics and useful results
Mehta, Madan Lal
1989-01-01
Matrices and operations on matrices ; determinants ; elementary operations on matrices (continued) ; eigenvalues and eigenvectors, diagonalization of normal matrices ; functions of a matrix ; positive definiteness, various polar forms of a matrix ; special matrices ; matrices with quaternion elements ; inequalities ; generalised inverse of a matrix ; domain of values of a matrix, location and dispersion of eigenvalues ; symmetric functions ; integration over matrix variables ; permanents of doubly stochastic matrices ; infinite matrices ; Alexander matrices, knot polynomials, torsion numbers.
Regularization in Matrix Relevance Learning
Schneider, Petra; Bunte, Kerstin; Stiekema, Han; Hammer, Barbara; Villmann, Thomas; Biehl, Michael
A In this paper, we present a regularization technique to extend recently proposed matrix learning schemes in learning vector quantization (LVQ). These learning algorithms extend the concept of adaptive distance measures in LVQ to the use of relevance matrices. In general, metric learning can
Parallel Sparse Matrix - Vector Product
DEFF Research Database (Denmark)
Alexandersen, Joe; Lazarov, Boyan Stefanov; Dammann, Bernd
This technical report contains a case study of a sparse matrix-vector product routine, implemented for parallel execution on a compute cluster with both pure MPI and hybrid MPI-OpenMP solutions. C++ classes for sparse data types were developed and the report shows how these class can be used...
Supersymmetry in Random Matrix Theory
Guhr, Thomas
2010-01-01
Supersymmetry is nowadays indispensable for many problems in Random Matrix Theory. It is presented here with an emphasis on conceptual and structural issues. An introduction to supermathematics is given. The Hubbard-Stratonovich transformation as well as its generalization and superbosonization are explained. The supersymmetric non-linear sigma model, Brownian motion in superspace and the color-flavor transformation are discussed.
The COMPADRE Plant Matrix Database
DEFF Research Database (Denmark)
2014-01-01
COMPADRE contains demographic information on hundreds of plant species. The data in COMPADRE are in the form of matrix population models and our goal is to make these publicly available to facilitate their use for research and teaching purposes. COMPADRE is an open-access database. We only request...
Open Membranes in Matrix Theory
Li, Miao
1996-01-01
We discuss how to construct open membranes in the recently proposed matrix model of M theory. In order to sustain an open membrane, two boundary terms are needed in the construction. These boundary terms are available in the system of the longitudinal five-branes and D0-branes.
Hyper-systolic matrix multiplication
Lippert, Th.; Petkov, N.; Palazzari, P.; Schilling, K.
A novel parallel algorithm for matrix multiplication is presented. It is based on a 1-D hyper-systolic processor abstraction. The procedure can be implemented on all types of parallel systems. (C) 2001 Elsevier Science B,V. All rights reserved.
Bilateral matrix-exponential distributions
DEFF Research Database (Denmark)
Bladt, Mogens; Esparza, Luz Judith R; Nielsen, Bo Friis
2012-01-01
In this article we define the classes of bilateral and multivariate bilateral matrix-exponential distributions. These distributions have support on the entire real space and have rational moment-generating functions. These distributions extend the class of bilateral phasetype distributions of [1]...
Extracellular matrix and wound healing.
Maquart, F X; Monboisse, J C
2014-04-01
Extracellular matrix has been known for a long time as an architectural support for the tissues. Many recent data, however, have shown that extracellular matrix macromolecules (collagens, elastin, glycosaminoglycans, proteoglycans and connective tissue glycoproteins) are able to regulate many important cell functions, such as proliferation, migration, protein synthesis or degradation, apoptosis, etc., making them able to play an important role in the wound repair process. Not only the intact macromolecules but some of their specific domains, that we called "Matrikines", are also able to regulate many cell activities. In this article, we will summarize main findings showing the effects of extracellular matrix macromolecules and matrikines on connective tissue and epithelial cells, particularly in skin, and their potential implication in the wound healing process. These examples show that extracellular matrix macromolecules or some of their specific domains may play a major role in wound healing. Better knowledge of these interactions may suggest new therapeutic targets in wound healing defects. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
Unravelling the nuclear matrix proteome
DEFF Research Database (Denmark)
Albrethsen, Jakob; Knol, Jaco C; Jimenez, Connie R
2009-01-01
The nuclear matrix (NM) model posits the presence of a protein/RNA scaffold that spans the mammalian nucleus. The NM proteins are involved in basic nuclear function and are a promising source of protein biomarkers for cancer. Importantly, the NM proteome is operationally defined as the proteins...
Matrix metalloproteinases in fish biology and matrix turnover.
Pedersen, Mona E; Vuong, Tram T; Rønning, Sissel B; Kolset, Svein O
2015-01-01
Matrix metalloproteinases have important functions for tissue turnover in fish, with relevance both for the fish industry and molecular and cellular research on embryology, inflammation and tissue repair. These metalloproteinases have been studied in different fish types, subjected to both aquaculture and experimental conditions. This review highlights studies on these metalloproteinases in relation to both fish quality and health and further, the future importance of fish for basic research studies. Copyright © 2015. Published by Elsevier B.V.
Zhang, Feng; Lubach, Joseph; Na, Watson; Momin, Samad
2016-08-01
Interaction between Polyox N12K and Carbopol 907 was pH dependent. A hydrogen bond-induced complexation began between pH 5.0 and 6.0 in an aqueous medium, and the interpolymer complex started to precipitate when the pH fell to 4.0. This complex was amorphous with a glass transition temperature of 3.17°C. The molar ratio between ethylene oxide and acrylic acid units in the complex was 1.3:1. About 46% of the COOH groups in Carbopol 907 were H bonded to ether oxygen in Polyox. Theophylline release from tablets containing both polymers was a function of dissolution media pH, due to the pH-dependent interactions. In 0.01 N HCl, an insoluble tablet matrix formed in situ. 93% drug was released over 27 h via Fickian diffusion. In acetate buffer pH 4.0, the insoluble tablet matrix formed in situ disintegrated into tiny gel particles. Gel erosion controlled drug release at pH 4.0. These 2 polymers were unable to complex in a phosphate buffer pH 6.8. Therefore, the tablet matrix dissolved, and drug release followed the anomalous transport mechanism at pH 6.8. The release profiles in an acetate buffer pH 4.0 and phosphate buffer pH 6.8 were statistically same, and a sustained release over 12 h was achieved. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.
Matrix Factorization for Evolution Data
Directory of Open Access Journals (Sweden)
Xiao-Yu Huang
2014-01-01
Full Text Available We study a matrix factorization problem, that is, to find two factor matrices U and V such that R≈UT×V, where R is a matrix composed of the values of the objects O1,O2,…,On at consecutive time points T1,T2,…,Tt. We first present MAFED, a constrained optimization model for this problem, which straightforwardly performs factorization on R. Then based on the interplay of the data in U, V, and R, a probabilistic graphical model using the same optimization objects is constructed, in which structural dependencies of the data in these matrices are revealed. Finally, we present a fitting algorithm to solve the proposed MAFED model, which produces the desired factorization. Empirical studies on real-world datasets demonstrate that our approach outperforms the state-of-the-art comparison algorithms.
Giddings, Steven B
2010-01-01
We investigate the hypothesized existence of an S-matrix for gravity, and some of its expected general properties. We first discuss basic questions regarding existence of such a matrix, including those of infrared divergences and description of asymptotic states. Distinct scattering behavior occurs in the Born, eikonal, and strong gravity regimes, and we describe aspects of both the partial wave and momentum space amplitudes, and their analytic properties, from these regimes. Classically the strong gravity region would be dominated by formation of black holes, and we assume its unitary quantum dynamics is described by corresponding resonances. Masslessness limits some powerful methods and results that apply to massive theories, though a continuation path implying crossing symmetry plausibly still exists. Physical properties of gravity suggest nonpolynomial amplitudes, although crossing and causality constrain (with modest assumptions) this nonpolynomial behavior, particularly requiring a polynomial bound in c...
Octonions in random matrix theory
Forrester, Peter J.
2017-04-01
The octonions are one of the four normed division algebras, together with the real, complex and quaternion number systems. The latter three hold a primary place in random matrix theory, where in applications to quantum physics they are determined as the entries of ensembles of Hermitian random matrices by symmetry considerations. Only for N=2 is there an existing analytic theory of Hermitian random matrices with octonion entries. We use a Jordan algebra viewpoint to provide an analytic theory for N=3. We then proceed to consider the matrix structure X†X, when X has random octonion entries. Analytic results are obtained from N=2, but are observed to break down in the 3×3 case.
Random matrix improved subspace clustering
Couillet, Romain
2017-03-06
This article introduces a spectral method for statistical subspace clustering. The method is built upon standard kernel spectral clustering techniques, however carefully tuned by theoretical understanding arising from random matrix findings. We show in particular that our method provides high clustering performance while standard kernel choices provably fail. An application to user grouping based on vector channel observations in the context of massive MIMO wireless communication networks is provided.
Random matrix theory within superstatistics
Abul-Magd, A. Y.
2005-01-01
We propose a generalization of the random matrix theory following the basic prescription of the recently suggested concept of superstatistics. Spectral characteristics of systems with mixed regular-chaotic dynamics are expressed as weighted averages of the corresponding quantities in the standard theory assuming that the mean level spacing itself is a stochastic variable. We illustrate the method by calculating the level density, the nearest-neighbor-spacing distributions and the two-level co...
Staggered chiral random matrix theory
Osborn, James C.
2010-01-01
We present a random matrix theory (RMT) for the staggered lattice QCD Dirac operator. The staggered RMT is equivalent to the zero-momentum limit of the staggered chiral Lagrangian and includes all taste breaking terms at their leading order. This is an extension of previous work which only included some of the taste breaking terms. We will also present some results for the taste breaking contributions to the partition function and the Dirac eigenvalues.
Octonions in random matrix theory
Forrester, Peter J.
2016-01-01
The octonions are one of the four normed division algebras, together with the real, complex and quaternion number systems. The latter three hold a primary place in random matrix theory, where in applications to quantum physics they are determined as the entries of ensembles of Hermitian random by symmetry considerations. Only for $N=2$ is there an existing analytic theory of Hermitian random matrices with octonion entries. We use a Jordan algebra viewpoint to provide an analytic theory for $N...
Multivariate Matrix-Exponential Distributions
DEFF Research Database (Denmark)
Bladt, Mogens; Nielsen, Bo Friis
2010-01-01
In this article we consider the distributions of non-negative random vectors with a joint rational Laplace transform, i.e., a fraction between two multi-dimensional polynomials. These distributions are in the univariate case known as matrix-exponential distributions, since their densities can be ...... for the multivariate normal distribution. However, the proof is different and involves theory for rational function based on continued fractions and Hankel determinants....
Distributed-memory matrix computations
DEFF Research Database (Denmark)
Balle, Susanne Mølleskov
1995-01-01
The main goal of this project is to investigate, develop, and implement algorithms for numerical linear algebra on parallel computers in order to acquire expertise in methods for parallel computations. An important motivation for analyzaing and investigating the potential for parallelism in these......The main goal of this project is to investigate, develop, and implement algorithms for numerical linear algebra on parallel computers in order to acquire expertise in methods for parallel computations. An important motivation for analyzaing and investigating the potential for parallelism....... Several areas in the numerical linear algebra field are investigated and they illustrate the problems that arise as well as the techniques that are related to the use of massively parallel computers: 1.Study of Strassen's matrix-matrix multiplication on the Connection Machine model CM-200. What...... performance can we expect to achieve? Why? 2.Solving systems of linear equations using a Strassen-type matrix-inversion algorithm. A good way to solve systems of linear equations on massively parallel computers? 3.Aspects of computing the singular value decomposition on the Connec-tion Machine CM-5/CM-5E...
MALDI Matrix Research for Biopolymers
Fukuyama, Yuko
2015-01-01
Matrices are necessary materials for ionizing analytes in matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). The choice of a matrix appropriate for each analyte controls the analyses. Thus, in some cases, development or improvement of matrices can become a tool for solving problems. This paper reviews MALDI matrix research that the author has conducted in the recent decade. It describes glycopeptide, carbohydrate, or phosphopeptide analyses using 2,5-dihydroxybenzoic acid (2,5-DHB), 1,1,3,3-tetramethylguanidinium (TMG) salts of p-coumaric acid (CA) (G3CA), 3-aminoquinoline (3-AQ)/α-cyano-4-hydroxycinnamic acid (CHCA) (3-AQ/CHCA) or 3-AQ/CA and gengeral peptide, peptide containing disulfide bonds or hydrophobic peptide analyses using butylamine salt of CHCA (CHCAB), 1,5-diaminonaphthalene (1,5-DAN), octyl 2,5-dihydroxybenzoate (alkylated dihydroxybenzoate, ADHB), or 1-(2,4,6-trihydroxyphenyl)octan-1-one (alkylated trihydroxyacetophenone, ATHAP). PMID:26819908
Superstatistics in Random Matrix Theory
Directory of Open Access Journals (Sweden)
A.Y. Abul-Magd
2012-12-01
Full Text Available Random matrix theory (RMT provides a successful model for quantum systems, whose classical counterpart has chaotic dynamics. It is based on two assumptions: (1 matrix-element independence, and (2 base invariance. The last decade witnessed several attempts to extend RMT to describe quantum systems with mixed regular-chaotic dynamics. Most of the proposed generalizations keep the first assumption and violate the second. Recently, several authors have presented other versions of the theory that keep base invariance at the expense of allowing correlations between matrix elements. This is achieved by starting from non-extensive entropies rather than the standard Shannon entropy, or by following the basic prescription of the recently suggested concept of superstatistics. The latter concept was introduced as a generalization of equilibrium thermodynamics to describe non-equilibrium systems by allowing the temperature to fluctuate. We here review the superstatistical generalizations of RMT and illustrate their value by calculating the nearest-neighbor-spacing distributions and comparing the results of calculation with experiments on billiards modeling systems in transition from order to chaos.
Vaičiūnas, Kęstutis; Auškalnis, Stasys; Matjošaitis, Aivaras; Mickevičius, Antanas; Mickevičius, Ramūnas; Trumbeckas, Darius; Jievaltas, Mindaugas
2007-01-01
Tyrimo tikslas. Nustatyti pakartotinių kraštinių sekstantinių prostatos biopsijų reikšmę diagnozuojant prostatos vėžį. Tyrimo metodai. Į tyrimą įtraukti 195 vyrai, apsilankę Kauno medicinos universiteto konsultacinėje poliklinikoje 2003–2007 metais dėl padidėjusios prostatos vėžio rizikos (padidėjusio prostatos specifinio antigeno (PSA) ir (ar) patologinių pokyčių prostatoje, nustatytų digitalinio rektalinio tyrimo metu). Visiems tiriamiesiems atlikta kraštinė sekstantinė prostatos biopsij...
"On some definitions in matrix algebra"
2007-01-01
Many definitions in matrix algebra are not standardized. This notediscusses some of thepitfalls associated with undesirable orwrong definitions, anddealswith central conceptslikesymmetry, orthogonality, square root, Hermitian and quadratic forms, and matrix derivatives.
Analytic matrix elements with shifted correlated Gaussians
DEFF Research Database (Denmark)
Fedorov, D. V.
2017-01-01
Matrix elements between shifted correlated Gaussians of various potentials with several form-factors are calculated analytically. Analytic matrix elements are of importance for the correlated Gaussian method in quantum few-body physics....
Cubic Matrix, Nambu Mechanics and Beyond
Yoshiharu, KAWAMURA; Department of Physics, Shinshu University
2003-01-01
We propose a generalization of cubic matrix mechanics by introducing a canonical triplet and study its relation to Nambu mechanics. The generalized cubic matrix mechanics we consider can be interpreted as a 'quantum' generalization of Nambu mechanics.
Cubic Matrix, Nambu Mechanics and Beyond
Kawamura, Y.
2002-01-01
We propose a generalization of cubic matrix mechanics by introducing a canonical triplet and study its relation to Nambu mechanics. The generalized cubic matrix mechanics we consider can be interpreted as a “quantum” generalization of Nambu mechanics.
Glomerular extracellular matrix components and integrins
Sterk, L. M.; de Melker, A. A.; Kramer, D.; Kuikman, I.; Chand, A.; Claessen, N.; Weening, J. J.; Sonnenberg, A.
1998-01-01
It has become apparent that extracellular matrix components and their cellular receptors, the integrins, are important regulators of glomerular development and function. In this rapidly evolving field we studied the production of extracellular matrix components and integrins by rat glomerular
The Theory of Quaternion Matrix Derivatives
Xu, Dongpo; Mandic, Danilo P.
2014-01-01
A systematic theory is introduced for calculating the derivatives of quaternion matrix function with respect to quaternion matrix variables. The proposed methodology is equipped with the matrix product rule and chain rule and it is able to handle both analytic and nonanalytic functions. This corrects a flaw in the existing methods, that is, the incorrect use of the traditional product rule. In the framework introduced, the derivatives of quaternion matrix functions can be calculated directly ...
Efficient Robust Matrix Factorization with Nonconvex Penalties
Yao, Quanming
2017-01-01
Robust matrix factorization (RMF) is a fundamental tool with lots of applications. The state-of-art is robust matrix factorization by majorization and minimization (RMF-MM) algorithm. It iteratively constructs and minimizes a novel surrogate function. Besides, it is also the only RMF algorithm with convergence guarantee. However, it can only deal with the convex $\\ell_1$-loss and does not utilize sparsity when matrix is sparsely observed. In this paper, we proposed robust matrix factorization...
The matrix reorganized: extracellular matrix remodeling and integrin signaling.
Larsen, Melinda; Artym, Vira V; Green, J Angelo; Yamada, Kenneth M
2006-10-01
Via integrins, cells can sense dimensionality and other physical and biochemical properties of the extracellular matrix (ECM). Cells respond differently to two-dimensional substrates and three-dimensional environments, activating distinct signaling pathways for each. Direct integrin signaling and indirect integrin modulation of growth factor and other intracellular signaling pathways regulate ECM remodeling and control subsequent cell behavior and tissue organization. ECM remodeling is critical for many developmental processes, and remodeled ECM contributes to tumorigenesis. These recent advances in the field provide new insights and raise new questions about the mechanisms of ECM synthesis and proteolytic degradation, as well as the roles of integrins and tension in ECM remodeling.
Matrix algebra for higher order moments
Meijer, Erik
2005-01-01
A large part of statistics is devoted to the estimation of models from the sample covariance matrix. The development of the statistical theory and estimators has been greatly facilitated by the introduction of special matrices, such as the commutation matrix and the duplication matrix, and the
Minimal solution for inconsistent singular fuzzy matrix equations
Nikuie, M.; M.K. Mirnia
2013-01-01
The fuzzy matrix equations $Ailde{X}=ilde{Y}$ is called a singular fuzzy matrix equations while the coefficients matrix of its equivalent crisp matrix equations be a singular matrix. The singular fuzzy matrix equations are divided into two parts: consistent singular matrix equations and inconsistent fuzzy matrix equations. In this paper, the inconsistent singular fuzzy matrix equations is studied and the effect of generalized inverses in finding minimal solution of an inconsistent singular fu...
The COMPADRE Plant Matrix Database
DEFF Research Database (Denmark)
Salguero-Gomez, Roberto; Jones, Owen; Archer, C. Ruth
2015-01-01
biological interpretations, facilitating comparisons among populations and species. 3. Thousands of plant matrix population models have been parameterized from empirical data, but they are largely dispersed through peer reviewed and grey literature, and thus remain inaccessible for synthetic analysis. Here...... information (e.g. ecoregion, growth form, taxonomy, phylogeny, etc.) that facilitates interpretation of the numerous demographic metrics that can be derived from the matrices. 4. Synthesis: Large collections of datasets allow broad questions to be addressed at the global scale, e.g. in genetics (Gen...
Linear algebra and matrix analysis for statistics
Banerjee, Sudipto
2014-01-01
Matrices, Vectors, and Their OperationsBasic definitions and notations Matrix addition and scalar-matrix multiplication Matrix multiplication Partitioned matricesThe ""trace"" of a square matrix Some special matricesSystems of Linear EquationsIntroduction Gaussian elimination Gauss-Jordan elimination Elementary matrices Homogeneous linear systems The inverse of a matrixMore on Linear EquationsThe LU decompositionCrout's Algorithm LU decomposition with row interchanges The LDU and Cholesky factorizations Inverse of partitioned matrices The LDU decomposition for partitioned matricesThe Sherman-W
MatrixPlot: visualizing sequence constraints
DEFF Research Database (Denmark)
Gorodkin, Jan; Stærfeldt, Hans Henrik; Lund, Ole
1999-01-01
MatrixPlot: visualizing sequence constraints. Sub-title Abstract Summary : MatrixPlot is a program for making high-quality matrix plots, such as mutual information plots of sequence alignments and distance matrices of sequences with known three-dimensional coordinates. The user can add information...... about the sequences (e.g. a sequence logo profile) along the edges of the plot, as well as zoom in on any region in the plot. Availability : MatrixPlot can be obtained on request, and can also be accessed online at http://www. cbs.dtu.dk/services/MatrixPlot. Contact : gorodkin@cbs.dtu.dk...
Matrix stiffening promotes a tumor vasculature phenotype.
Bordeleau, Francois; Mason, Brooke N; Lollis, Emmanuel Macklin; Mazzola, Michael; Zanotelli, Matthew R; Somasegar, Sahana; Califano, Joseph P; Montague, Christine; LaValley, Danielle J; Huynh, John; Mencia-Trinchant, Nuria; Negrón Abril, Yashira L; Hassane, Duane C; Bonassar, Lawrence J; Butcher, Jonathan T; Weiss, Robert S; Reinhart-King, Cynthia A
2017-01-17
Tumor microvasculature tends to be malformed, more permeable, and more tortuous than vessels in healthy tissue, effects that have been largely attributed to up-regulated VEGF expression. However, tumor tissue tends to stiffen during solid tumor progression, and tissue stiffness is known to alter cell behaviors including proliferation, migration, and cell-cell adhesion, which are all requisite for angiogenesis. Using in vitro, in vivo, and ex ovo models, we investigated the effects of matrix stiffness on vessel growth and integrity during angiogenesis. Our data indicate that angiogenic outgrowth, invasion, and neovessel branching increase with matrix cross-linking. These effects are caused by increased matrix stiffness independent of matrix density, because increased matrix density results in decreased angiogenesis. Notably, matrix stiffness up-regulates matrix metalloproteinase (MMP) activity, and inhibiting MMPs significantly reduces angiogenic outgrowth in stiffer cross-linked gels. To investigate the functional significance of altered endothelial cell behavior in response to matrix stiffness, we measured endothelial cell barrier function on substrates mimicking the stiffness of healthy and tumor tissue. Our data indicate that barrier function is impaired and the localization of vascular endothelial cadherin is altered as function of matrix stiffness. These results demonstrate that matrix stiffness, separately from matrix density, can alter vascular growth and integrity, mimicking the changes that exist in tumor vasculature. These data suggest that therapeutically targeting tumor stiffness or the endothelial cell response to tumor stiffening may help restore vessel structure, minimize metastasis, and aid in drug delivery.
Mueller matrix roots algorithm and computational considerations.
Noble, H D; Chipman, R A
2012-01-02
Recently, an order-independent Mueller matrix decomposition was proposed in an effort to elucidate the nine depolarization degrees of freedom [Handbook of Optics, Vol. 1 of Mueller Matrices (2009)]. This paper addresses the critical computational issues involved in applying this Mueller matrix roots decomposition, along with a review of the principal matrix root and common methods for its calculation. The calculation of the pth matrix root is optimized around p = 10(5) for a 53 digit binary double precision calculation. A matrix roots algorithm is provided which incorporates these computational results. It is applied to a statistically significant number of randomly generated physical Mueller matrices in order to gain insight on the typical ranges of the depolarizing Matrix roots parameters. Computational techniques are proposed which allow singular Mueller matrices and Mueller matrices with a half-wave of retardance to be evaluated with the matrix roots decomposition.
Fragmentation of extracellular matrix by hypochlorous acid
DEFF Research Database (Denmark)
Woods, Alan A; Davies, Michael Jonathan
2003-01-01
of the MPO-derived oxidant hypochlorous acid (HOCl) with extracellular matrix from vascular smooth muscle cells and healthy pig arteries has been examined. HOCl is rapidly consumed by such matrix samples, with the formation of matrix-derived chloramines or chloramides. The yield of these intermediates...... increases with HOCl dose. These materials undergo a time- and temperature-dependent decay, which parallels the release of sugar and protein components from the treated matrix, consistent with these species being important intermediates. Matrix damage is enhanced by species that increase chloramine....../chloramide decomposition, with copper and iron ions being effective catalysts, and decreased by compounds which scavenge chloramines/chloramides, or species derived from them. The effect of such matrix modifications on cellular behaviour is poorly understood, though it is known that changes in matrix materials can have...
Extracellular Matrix and Liver Disease
Arriazu, Elena; Ruiz de Galarreta, Marina; Cubero, Francisco Javier; Varela-Rey, Marta; Pérez de Obanos, María Pilar; Leung, Tung Ming; Lopategi, Aritz; Benedicto, Aitor; Abraham-Enachescu, Ioana
2014-01-01
Abstract Significance: The extracellular matrix (ECM) is a dynamic microenvironment that undergoes continuous remodeling, particularly during injury and wound healing. Chronic liver injury of many different etiologies such as viral hepatitis, alcohol abuse, drug-induced liver injury, obesity and insulin resistance, metabolic disorders, and autoimmune disease is characterized by excessive deposition of ECM proteins in response to persistent liver damage. Critical Issues: This review describes the main collagenous and noncollagenous components from the ECM that play a significant role in pathological matrix deposition during liver disease. We define how increased myofibroblasts (MF) from different origins are at the forefront of liver fibrosis and how liver cell-specific regulation of the complex scarring process occurs. Recent Advances: Particular attention is paid to the role of cytokines, growth factors, reactive oxygen species, and newly identified matricellular proteins in the regulation of fibrillar type I collagen, a field to which our laboratory has significantly contributed over the years. We compile data from recent literature on the potential mechanisms driving fibrosis resolution such as MF’ apoptosis, senescence, and reversal to quiescence. Future Directions: We conclude with a brief description of how epigenetics, an evolving field, can regulate the behavior of MF and of how new “omics” tools may advance our understanding of the mechanisms by which the fibrogenic response to liver injury occurs. Antioxid. Redox Signal. 21, 1078–1097. PMID:24219114
Interpolation of rational matrix functions
Ball, Joseph A; Rodman, Leiba
1990-01-01
This book aims to present the theory of interpolation for rational matrix functions as a recently matured independent mathematical subject with its own problems, methods and applications. The authors decided to start working on this book during the regional CBMS conference in Lincoln, Nebraska organized by F. Gilfeather and D. Larson. The principal lecturer, J. William Helton, presented ten lectures on operator and systems theory and the interplay between them. The conference was very stimulating and helped us to decide that the time was ripe for a book on interpolation for matrix valued functions (both rational and non-rational). When the work started and the first partial draft of the book was ready it became clear that the topic is vast and that the rational case by itself with its applications is already enough material for an interesting book. In the process of writing the book, methods for the rational case were developed and refined. As a result we are now able to present the rational case as an indepe...
Characterization of Metal Matrix Composites
Daniel, I. M.; Chun, H. J.; Karalekas, D.
1994-01-01
Experimental methods were developed, adapted, and applied to the characterization of a metal matrix composite system, namely, silicon carbide/aluminim (SCS-2/6061 Al), and its constituents. The silicon carbide fiber was characterized by determining its modulus, strength, and coefficient of thermal expansion. The aluminum matrix was characterized thermomechanically up to 399 C (750 F) at two strain rates. The unidirectional SiC/Al composite was characterized mechanically under longitudinal, transverse, and in-plane shear loading up to 399 C (750 F). Isothermal and non-isothermal creep behavior was also measured. The applicability of a proposed set of multifactor thermoviscoplastic nonlinear constitutive relations and a computer code was investigated. Agreement between predictions and experimental results was shown in a few cases. The elastoplastic thermomechanical behavior of the composite was also described by a number of new analytical models developed or adapted for the material system studied. These models include the rule of mixtures, composite cylinder model with various thermoelastoplastic analyses and a model based on average field theory. In most cases satisfactory agreement was demonstrated between analytical predictions and experimental results for the cases of stress-strain behavior and thermal deformation behavior at different temperatures. In addition, some models yielded detailed three-dimensional stress distributions in the constituents within the composite.
New fault tolerant matrix converter
Energy Technology Data Exchange (ETDEWEB)
Ibarra, Edorta; Andreu, Jon; Kortabarria, Inigo; Ormaetxea, Enekoitz; Alegria, Inigo Martinez de; Martin, Jose Luis [Department of Electronics and Telecommunications, University of the Basque Country, Alameda de Urquijo s/n, E-48013 Bilbao (Spain); Ibanez, Pedro [TECNALIA, Energy Unit, Parque Tecnologico de Zamudio, E-48170 Bizkaia (Spain)
2011-02-15
The matrix converter (MC) presents a promising topology that will have to overcome certain barriers (protection systems, durability, the development of converters for real applications, etc.) in order to gain a foothold in the industry. In some applications, where continuous operation must be insured in the case of a system failure, improved reliability of the converter is of particular importance. In this sense, this article focuses on the study of a fault tolerant MC. The fault tolerance of a converter is characterized by its total or partial response in the case of a breakage of any of its components. Taking into consideration that virtually no work has been done on fault tolerant MCs, this paper describes the most important studies in this area. Moreover, a new method is proposed for detecting the breakage of MC semiconductors. Likewise, a new variation of SVM modulation with failure tolerance capacity is presented. This guarantees the continuous operation of the converter and the pseudo-optimum control of a PMSM. This paper also proposes a novel MC topology, which allows the flexible reconfiguration of this converter, when one or several of its semiconductors are damaged. In this way, the MC can continue operating at 100% of its performance without having to double its resources. In this way, it can be said that the solution described in this article represents a step forward towards the development of reliable matrix converters for real applications. (author)
Automatic Generation of Partitioned Matrix Expressions for Matrix Operations
Fabregat-Traver, Diego; Bientinesi, Paolo
2010-09-01
We target the automatic generation of formally correct algorithms and routines for linear algebra operations. Given the broad variety of architectures and configurations with which scientists deal, there does not exist one algorithmic variant that is suitable for all scenarios. Therefore, we aim to generate a family of algorithmic variants to attain high-performance for a broad set of scenarios. One of the authors has previously demonstrated that automatic derivation of a family of algorithms is possible when the Partitioned Matrix Expression (PME) of the target operation is available. The PME is a recursive definition that states the relations between submatrices in the input and the output operands. In this paper we describe all the steps involved in the automatic derivation of PMEs, thus making progress towards a fully automated system.
Energy Technology Data Exchange (ETDEWEB)
Basile, F. [Centre d`Etudes de Chimie Metallurgique, 94 - Vitry-sur-Seine (France)
1997-05-01
TiNi alloys are potentially able to include in their structure a significant quantity of hydrogen which allows them to be used as electrodes in hydrogen batteries providing their electrical characteristics are suitable. TiNi alloys were produced in hyperquenched tape shape. These tapes were then electrolytically hydrided. X-ray analysis of hydrided and nonhydrided samples was performed. In the hyperquenched tape the B2 and the ``R``(H) phases, the presence of which is linked to the hyperquenched constraints, coexist. The hydrided electrolytically hyperquenched tape has the TiNiH{sub x} (x 0.3) formula and contains the two hydrided forms corresponding to those that are unhydrided. At around 100{sup o}C, under hydrogen gas, the quadratic hydride parent of B2 remains alone. The TiNiH{sub 0.3} sample has been analysed using differential calorimetry under argon and hydrogen gas. In the cubic structure only two octahedral sites are occupied by hydrogen. In TiNiH{sub 0.3} only the smaller octahedral sites are occupied by electrolytic hydrogen. If TiNiH{sub 0.3} is then charged with hydrogen gas, this gas occupies the other larger octahedral site. The hydride has the formula TiNiH{sub 0.85}. (Author)
Burugapalli, Krishna; Chan, Jeffrey C Y; Kelly, John L; Pandit, Abhay S
2014-02-01
Cholecyst-derived extracellular matrix (CEM) is a fibro-porous decellularized serosal layer of porcine gall-bladder. CEM loses 90% of its weight at 48 h of in vitro collagenase digestion, but takes two months to be completely resorbed in vivo. Carbodiimide (EDC) crosslinking helps tailoring CEM's in vitro collagenase susceptibility. Here, the efficacy of EDC crosslinking on tailoring in vivo biodegradability of CEM is reported. CEM crosslinked with 0.0005 and 0.0033 × 10(3) M of EDC/mg that lose 80% and 0% of their weight respectively to in vitro collagenase digestion, were present even after 180 days in vivo. Quantitative histopathology using stereology methods confirmed our qualitative observation that even a tiny degree of crosslinking can significantly prolong the rate of in vivo degradation and removal of CEM. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Inequalities involving upper bounds for certain matrix operators
Indian Academy of Sciences (India)
Home; Journals; Proceedings – Mathematical Sciences; Volume 116; Issue 3. Inequalities Involving Upper Bounds for Certain Matrix Operators. R Lashkaripour D Foroutannia. Volume ... Keywords. Inequality; norm; summability matrix; Hausdorff matrix; Hilbert matrix; weighted sequence space; Lorentz sequence space.
Collision matrix for Leo satellites
McKnight, Darren; Lorenzen, Gary
The Low Earth Orbit (LEO) is becoming cluttered with thousands of satellites, rocket bodies, and a variety of space garbage. This collection of objects crossing paths at speeds on the order of 10 km/s is creating an increasing collision hazard to many operational systems. The effect that the destruction of LEO satellites will have on other users of the near-Earth environment is of great concern. A model is examined which quantifies the effect of one satellite fragmentation on neighboring satellites. This model is used to evaluate the interdependent hazard to a series of satellite systems. A number of space system fragmentation events are numerically simulated and the collision hazard to each is tabulated. Once all satellites in the matrix have been fragmented separately, a complete collision hazard representation can be depicted. This model has potential for developing an enhanced understanding of a number of aspects of the growing debris hazard in LEO.
The Biblical Matrix of Economics
Directory of Open Access Journals (Sweden)
Grigore PIROŞCĂ
2012-05-01
Full Text Available The rationale of this paper is a prime pattern of history of economic thought in the previous ages of classic ancient times of Greek and Roman civilizations using a methodological matrix able to capture the mainstream ideas from social, political and religious events within the pages of Bible. The economic perspective of these events follows the evolution of the seeds of economic thinking within the Fertile Crescent, focused on the Biblical patriarchic heroes’ actions, but also on the empires which their civilization interacted to. The paper aims to discover the path followed by the economic doctrines from the Bible in order to find a match with economic actuality of present days.
Optimized Projection Matrix for Compressive Sensing
Directory of Open Access Journals (Sweden)
Jianping Xu
2010-01-01
Full Text Available Compressive sensing (CS is mainly concerned with low-coherence pairs, since the number of samples needed to recover the signal is proportional to the mutual coherence between projection matrix and sparsifying matrix. Until now, papers on CS always assume the projection matrix to be a random matrix. In this paper, aiming at minimizing the mutual coherence, a method is proposed to optimize the projection matrix. This method is based on equiangular tight frame (ETF design because an ETF has minimum coherence. It is impossible to solve the problem exactly because of the complexity. Therefore, an alternating minimization type method is used to find a feasible solution. The optimally designed projection matrix can further reduce the necessary number of samples for recovery or improve the recovery accuracy. The proposed method demonstrates better performance than conventional optimization methods, which brings benefits to both basis pursuit and orthogonal matching pursuit.
Logarithmic universality in random matrix theory
Energy Technology Data Exchange (ETDEWEB)
Splittorff, K. E-mail: split@alf.nbi.dk
1999-05-24
Universality in unitary invariant random matrix ensembles with complex matrix elements is considered. We treat two general ensembles which have a determinant factor in the weight. These ensembles are relevant, e.g., for spectra of the Dirac operator in QCD. In addition to the well established universality with respect to the choice of potential, we prove that microscopic spectral correlators are unaffected when the matrix in the determinant is replaced by an expansion in powers of the matrix. We refer to this invariance as logarithmic universality. The result is used in proving that a simple random matrix model with Ginsparg-Wilson symmetry has the same microscopic spectral correlators as chiral random matrix theory.
Eigenvalues properties of terms correspondences matrix
Bondarchuk, Dmitry; Timofeeva, Galina
2016-12-01
Vector model representations of text documents are widely used in the intelligent search. In this approach a collection of documents is represented in the form of the term-document matrix, reflecting the frequency of terms. In the latent semantic analysis the dimension of the vector space is reduced by the singular value decomposition of the term-document matrix. Authors use a matrix of terms correspondences, reflecting the relationship between the terms, to allocate a semantic core and to obtain more simple presentation of the documents. With this approach, reducing the number of terms is based on the orthogonal decomposition of the matrix of terms correspondences. Properties of singular values of the term-document matrix and eigenvalues of the matrix of terms correspondences are studied in the case when documents differ substantially in length.
Corner Transfer Matrix Renormalization Group Method
Nishino, T.; Okunishi, K.
1995-01-01
We propose a new fast numerical renormalization group method,the corner transfer matrix renormalization group (CTMRG) method, which is based on a unified scheme of Baxter's corner transfer matrix method and White's density matrix renormalization groupmethod. The key point is that a product of four corner transfer matrices gives the densitymatrix. We formulate the CTMRG method as a renormalization of 2D classical models.
Matrix-assisted peptide synthesis on nanoparticles.
Khandadash, Raz; Machtey, Victoria; Weiss, Aryeh; Byk, Gerardo
2014-09-01
We report a new method for multistep peptide synthesis on polymeric nanoparticles of differing sizes. Polymeric nanoparticles were functionalized via their temporary embedment into a magnetic inorganic matrix that allows multistep peptide synthesis. The matrix is removed at the end of the process for obtaining nanoparticles functionalized with peptides. The matrix-assisted synthesis on nanoparticles was proved by generating various biologically relevant peptides. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.
A Generalization of the Alias Matrix
DEFF Research Database (Denmark)
Kulahci, Murat; Bisgaard, S.
2006-01-01
The investigation of aliases or biases is important for the interpretation of the results from factorial experiments. For two-level fractional factorials this can be facilitated through their group structure. For more general arrays the alias matrix can be used. This tool is traditionally based...... on the assumption that the error structure is that associated with ordinary least squares. For situations where that is not the case, we provide in this article a generalization of the alias matrix applicable under the generalized least squares assumptions. We also show that for the special case of split plot error...... structure, the generalized alias matrix simplifies to the ordinary alias matrix....
Biglycan Modulates Osteoblast Differentiation and Matrix Mineralization
National Research Council Canada - National Science Library
Parisuthiman, Duenpim; Mochida, Yoshiyuki; Duarte, Wagner R; Yamauchi, Mitsuo
2005-01-01
.... The processes of cell differentiation and matrix mineralization were accelerated in S but delayed in AS, indicating that BGN modulates osteoblastic cell differentiation. Introduction : Biglycan (BGN...
Finding Nonoverlapping Substructures of a Sparse Matrix
Energy Technology Data Exchange (ETDEWEB)
Pinar, Ali; Vassilevska, Virginia
2005-08-11
Many applications of scientific computing rely on computations on sparse matrices. The design of efficient implementations of sparse matrix kernels is crucial for the overall efficiency of these applications. Due to the high compute-to-memory ratio and irregular memory access patterns, the performance of sparse matrix kernels is often far away from the peak performance on a modern processor. Alternative data structures have been proposed, which split the original matrix A into A{sub d} and A{sub s}, so that A{sub d} contains all dense blocks of a specified size in the matrix, and A{sub s} contains the remaining entries. This enables the use of dense matrix kernels on the entries of A{sub d} producing better memory performance. In this work, we study the problem of finding a maximum number of nonoverlapping dense blocks in a sparse matrix, which is previously not studied in the sparse matrix community. We show that the maximum nonoverlapping dense blocks problem is NP-complete by using a reduction from the maximum independent set problem on cubic planar graphs. We also propose a 2/3-approximation algorithm that runs in linear time in the number of nonzeros in the matrix. This extended abstract focuses on our results for 2x2 dense blocks. However we show that our results can be generalized to arbitrary sized dense blocks, and many other oriented substructures, which can be exploited to improve the memory performance of sparse matrix operations.
Basic matrix algebra and transistor circuits
Zelinger, G
1963-01-01
Basic Matrix Algebra and Transistor Circuits deals with mastering the techniques of matrix algebra for application in transistors. This book attempts to unify fundamental subjects, such as matrix algebra, four-terminal network theory, transistor equivalent circuits, and pertinent design matters. Part I of this book focuses on basic matrix algebra of four-terminal networks, with descriptions of the different systems of matrices. This part also discusses both simple and complex network configurations and their associated transmission. This discussion is followed by the alternative methods of de
A random matrix theory of decoherence
Energy Technology Data Exchange (ETDEWEB)
Gorin, T [Departamento de FIsica, Universidad de Guadalajara, Blvd Marcelino GarcIa Barragan y Calzada OlImpica, Guadalajara CP 44840, JalIsco (Mexico); Pineda, C [Institut fuer Physik und Astronomie, University of Potsdam, 14476 Potsdam (Germany); Kohler, H [Fachbereich Physik, Universitaet Duisburg-Essen, D-47057 Duisburg (Germany); Seligman, T H [Instituto de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico (Mexico)], E-mail: thomas.gorin@red.cucei.udg.mx, E-mail: carlospgmat03@gmail.com
2008-11-15
Random matrix theory is used to represent generic loss of coherence of a fixed central system coupled to a quantum-chaotic environment, represented by a random matrix ensemble, via random interactions. We study the average density matrix arising from the ensemble induced, in contrast to previous studies where the average values of purity, concurrence and entropy were considered; we further discuss when one or the other approach is relevant. The two approaches agree in the limit of large environments. Analytic results for the average density matrix and its purity are presented in linear response approximation. The two-qubit system is analysed, mainly numerically, in more detail.
Titanium Matrix Composite Pressure Vessel Project
National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...
Matrix Krylov subspace methods for image restoration
Directory of Open Access Journals (Sweden)
khalide jbilou
2015-09-01
Full Text Available In the present paper, we consider some matrix Krylov subspace methods for solving ill-posed linear matrix equations and in those problems coming from the restoration of blurred and noisy images. Applying the well known Tikhonov regularization procedure leads to a Sylvester matrix equation depending the Tikhonov regularized parameter. We apply the matrix versions of the well known Krylov subspace methods, namely the Least Squared (LSQR and the conjugate gradient (CG methods to get approximate solutions representing the restored images. Some numerical tests are presented to show the effectiveness of the proposed methods.
Risk matrix model for rotating equipment
Directory of Open Access Journals (Sweden)
Wassan Rano Khan
2014-07-01
Full Text Available Different industries have various residual risk levels for their rotating equipment. Accordingly the occurrence rate of the failures and associated failure consequences categories are different. Thus, a generalized risk matrix model is developed in this study which can fit various available risk matrix standards. This generalized risk matrix will be helpful to develop new risk matrix, to fit the required risk assessment scenario for rotating equipment. Power generation system was taken as case study. It was observed that eight subsystems were under risk. Only vibration monitor system was under high risk category, while remaining seven subsystems were under serious and medium risk categories.
Oxytocin prevents cartilage matrix destruction via regulating matrix metalloproteinases.
Wu, Yixin; Wu, Tongyu; Xu, Binbin; Xu, Xiaoyan; Chen, Honggan; Li, Xiyao
2017-05-06
Degradation of the extracellular matrix type II Collagen (Col II) induced by proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) is an important hallmark of Osteoarthritis (OA). Oxytocin (OT) is a well-known neurohypophysical hormone that is synthesized in the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus. In this study, we have found that oxytocin receptor (OTR) was expressed in human primary chondrocytes, and the expression of which was reduced in chondrocytes from OA patients and in response to TNF-α treatment in a dose dependent manner. Notably, it was shown that TNF-α -induced degradation of Col II was restored by treatment with OT in a dose-dependent manner. In addition, TNF-α treatment (10 ng/mL) highly elevated the expression of MMP-1 and MMP-13 in SW1353 chondrocytes, which were reversed by OT in a dose dependent manner at both gene and protein expression levels. In addition, it was demonstrated that the JAK2/STAT1 pathway was involved in the restoration effects of OT in the degradation of Col II. Lastly, knockdown of OTR abolished the inhibitory effects of OT on the degradation of col II and the induction of MMP-1 and MMP-13 expression, suggesting the involvement of OTR. Our study implied the therapeutic potential of OT for cartilage degradation. Copyright © 2017 Elsevier Inc. All rights reserved.
Zhong, Zai-Zhe
2004-01-01
The partial separability of multipartite qubit density matrixes is strictly defined. We give a reduction way from N-partite qubit density matrixes to bipartite qubit density matrixes, and prove a necessary condition that a N-partite qubit density matrix to be partially separable is its reduced density matrix to satisfy PPT condition.
Energy Technology Data Exchange (ETDEWEB)
Bernard, C. (California Univ., Santa Barbara, CA (USA). Inst. for Theoretical Physics); Soni, A. (Brookhaven National Lab., Upton, NY (USA))
1989-01-01
We present results from the Wilson fermion part of the Grand Challenge'' weak matrix element project. A new procedure for correcting the chiral behavior of {Beta}{sub LL}{sup sd}, the K{sup 0}-{bar K}{sup 0} {Beta} parameter,'' is proposed and applied. On our largest lattice (24{sup 3} {times} 40 at {beta} = 6.0), we get {Beta}{sub LL}{sup sd} = .86 {plus minus} .11 {plus minus} .05, where the first error is statistical and the second is a measure of the systematic errors due to the procedure and to related finite-size effects. Results for the direct K{sup +} {yields} {pi}{sup +}{pi}{sup 0} amplitude are also presented. There is some evidence for higher order chiral effects which may make these results compatible both with experiment and with the {Beta}{sub LL}{sup sd} computation. The status of the direct K{sub s}{sup 0} {yields} {pi} {sup +} {pi}{sup {minus}} {Delta}I = 1/2 amplitude is then discussed. 11 refs., 6 figs., 1 tab.
Matrix metalloproteinases in myasthenia gravis.
Helgeland, Geir; Petzold, Axel; Luckman, Steven Paul; Gilhus, Nils Erik; Plant, Gordon T; Romi, Fredrik Robert
2011-01-01
Myasthenia gravis (MG) is an autoimmune disease with weakness in striated musculature due to anti-acetylcholine receptor (AChR) antibodies or muscle specific kinase at the neuromuscular junction. A subgroup of patients has periocular symptoms only; ocular MG (OMG). Matrix metalloproteinases (MMP) are increased in several autoimmune diseases, including generalized MG (GMG), and have been suggested to play a role in immune cell infiltration, basement membrane breakdown and autoimmune pathogenesis. Total levels of MMP2, MMP3 and MMP9 were measured in serum by ELISA. The MG patients had increased serum levels of MMP2 (median values 200.7 vs. 159.7 ng/ml, p < 0.001) and MMP9 (median values 629.6 vs. 386.4 ng/ml, p < 0.001) compared to controls. A subgroup of patients had increased MMP3 concentration (p = 0.001). The differences were not dependent on presence of AChR antibodies. No difference was observed between GMG and OMG patients with regard to MMP2 (p = 0.598), MMP3 (p = 0.450) and MMP9 (p = 0.271). The increased MMP levels in our MG patients group and the lack of dependence on anti-AChR antibodies suggest that MMP2, MMP3 and MMP9 play a role in the development of MG. The similarities between GMG and OMG support OMG as a systemic disease. Copyright © 2011 S. Karger AG, Basel.
Analysis Matrix for Smart Cities
Directory of Open Access Journals (Sweden)
Pablo E. Branchi
2014-01-01
Full Text Available The current digital revolution has ignited the evolution of communications grids and the development of new schemes for productive systems. Traditional technologic scenarios have been challenged, and Smart Cities have become the basis for urban competitiveness. The citizen is the one who has the power to set new scenarios, and that is why a definition of the way people interact with their cities is needed, as is commented in the first part of the article. At the same time, a lack of clarity has been detected in the way of describing what Smart Cities are, and the second part will try to set the basis for that. For all before, the information and communication technologies that manage and transform 21st century cities must be reviewed, analyzing their impact on new social behaviors that shape the spaces and means of communication, as is posed in the experimental section, setting the basis for an analysis matrix to score the different elements that affect a Smart City environment. So, as the better way to evaluate what a Smart City is, there is a need for a tool to score the different technologies on the basis of their usefulness and consequences, considering the impact of each application. For all of that, the final section describes the main objective of this article in practical scenarios, considering how the technologies are used by citizens, who must be the main concern of all urban development.
Matrix perturbations: bounding and computing eigenvalues
Reis da Silva, R.J.
2011-01-01
Despite the somewhat negative connotation of the word, not every perturbation is a bad perturbation. In fact, while disturbing the matrix entries, many perturbations still preserve useful properties such as the orthonormality of the basis of eigenvectors or the Hermicity of the original matrix. In
On the Subspace Projected Approximate Matrix method
Brandts, J.H.; Reis da Silva, R.
2015-01-01
We provide a comparative study of the Subspace Projected Approximate Matrix method, abbreviated SPAM, which is a fairly recent iterative method of computing a few eigenvalues of a Hermitian matrix A. It falls in the category of inner-outer iteration methods and aims to reduce the costs of
Differential analysis of matrix convex functions II
DEFF Research Database (Denmark)
Hansen, Frank; Tomiyama, Jun
2009-01-01
We continue the analysis in [F. Hansen, and J. Tomiyama, Differential analysis of matrix convex functions. Linear Algebra Appl., 420:102--116, 2007] of matrix convex functions of a fixed order defined in a real interval by differential methods as opposed to the characterization in terms of divide...
Fabrication of hybrid ceramic matrix composites
Haug, S. B.; Dharani, L. R.; Carroll, D. R.
1994-03-01
The desire to improve the transverse properties and microcracking stress of unidirectional continuous fiber reinforced ceramic matrix composites has led to development of the hybrid ceramic matrix composite (HCMC). This paper discusses the techniques we used in the fabrication of HCMC specimens used for mechanical characterization.
The Matrix exponential, Dynamic Systems and Control
DEFF Research Database (Denmark)
Poulsen, Niels Kjølstad
2004-01-01
The matrix exponential can be found in various connections in analysis and control of dynamic systems. In this short note we are going to list a few examples. The matrix exponential usably pops up in connection to the sampling process, whatever it is in a deterministic or a stochastic setting...
Modeling and Simulation of Matrix Converter
DEFF Research Database (Denmark)
Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede
2005-01-01
This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...
Preparation and Characterization of Sustained Release Matrix ...
African Journals Online (AJOL)
Purpose: To formulate matrix type sustained-release (SR) tablets of tizanidine hydrochloride (TH) for prolonged drug release and improvement in motor activity after spinal injuries. Methods: Matrix tablets were prepared by the wet granulation method using four polymers (hydroxyl propyl methyl cellulose [HPMC] K 100, ethyl ...
Efficient Matrix Models for Relational Learning
2009-10-01
New York, 1994. [63] Daniel D. Lee and H. Sebastian Seung . Algorithms for non-negative matrix factor- ization. In Todd K. Leen, Thomas G. Dietterich...135] Shenghuo Zhu, Kai Yu, Yun Chi, and Yihong Gong. Combining content and link for classification using matrix factorization. In Wessel Kraaij
Matrix subordinators and related Upsilon transformations
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Pérez-Abreu, V.
2008-01-01
A class of upsilon transformations of Lévy measures for matrix subordinators is introduced. Some regularizing properties of these transformations are derived, such as absolute continuity and complete monotonicity. The class of Lévy measures with completely monotone matrix densities is characterized....... Examples of infinitely divisible nonnegative definite random matrices are constructed using an upsilon transformation....
Photoacoustic measurement of lutein in biological matrix
Bicanic, D.D.; Luterotti, S.; Becucci, M.; Fogliano, V.; Versloot, P.
2005-01-01
Photoacoustic (PA) spectroscopy was applied for the first time to quantify lutein in a complex biological matrix. Standard addition of lutein to a biological low-lutein matrix was used for the calibration. The PA signal was found linearly proportional (R > 0.98) to lutein concentration up to 0.3%
Confocal microscopy imaging of the biofilm matrix
DEFF Research Database (Denmark)
Schlafer, Sebastian; Meyer, Rikke L
2017-01-01
The extracellular matrix is an integral part of microbial biofilms and an important field of research. Confocal laser scanning microscopy is a valuable tool for the study of biofilms, and in particular of the biofilm matrix, as it allows real-time visualization of fully hydrated, living specimens...
Some thoughts about matrix coordinate transformations
Energy Technology Data Exchange (ETDEWEB)
Adam, Joke [Instituut voor Theoretische Fysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)], E-mail: joke.adam@fys.kuleuven.be; Janssen, Bert [Departamento de Fisica Teorica y del Cosmos and Centro Andaluz de Fisica de Particulas Elementales, Universidad de Granada, 18071 Granada (Spain)], E-mail: bjanssen@ugr.es; Troost, Walter [Instituut voor Theoretische Fysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)], E-mail: walter.troost@fys.kuleuven.be; Herck, Walter van [Instituut voor Theoretische Fysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)], E-mail: walter.vanherck@fys.kuleuven.be
2008-04-17
Matrix coordinate transformations are defined as substitution operators without requiring an ordering prescription or an inclusion function from the Abelian coordinate transformations. We construct transforming objects mimicking most of the properties of tensors. We point out some problems with the matrix generalization of contravariant vectors. We suggest to use the substitution operators to search for an inclusion function.
Matrix multiplication operators on Banach function spaces
Indian Academy of Sciences (India)
Abstract. In this paper, we study the matrix multiplication operators on Banach function spaces and discuss their applications in semigroups for solving the abstract. Cauchy problem. Keywords. Banach function spaces; closed operators; compact operators; Fredholm operators; matrix multiplication operators; semigroups. 1.
Matrix approach to modelling of SAR signals
Lidicky, L.; Hoogeboom, P.
2005-01-01
The paper presents a matrix approach to implementation of SAR signal generating and processing schemes. This approach is advantageous when matrix oriented software such as Matlab is used. Algorithms written in this type of software packages run faster compared to the same algorithms written for the
Matrix model description of baryonic deformations
Energy Technology Data Exchange (ETDEWEB)
Bena, Iosif; Murayama, Hitoshi; Roiban, Radu; Tatar, Radu
2003-03-13
We investigate supersymmetric QCD with N{sub c} + 1 flavors using an extension of the recently proposed relation between gauge theories and matrix models.The impressive agreement between the two sides provides a beautiful confirmation of the extension of the gauge theory-matrix model relation to this case.
Matrix 3-Lie superalgebras and BRST supersymmetry
Abramov, Viktor
Given a matrix Lie algebra one can construct the 3-Lie algebra by means of the trace of a matrix. In the present paper, we show that this approach can be extended to the infinite-dimensional Lie algebra of vector fields on a manifold if instead of the trace of a matrix we consider a differential 1-form which satisfies certain conditions. Then we show that the same approach can be extended to matrix Lie superalgebras 𝔤𝔩(m,n) if instead of the trace of a matrix we make use of the supertrace of a matrix. It is proved that a graded triple commutator of matrices constructed with the help of the graded commutator and the supertrace satisfies a graded ternary Filippov-Jacobi identity. In two particular cases of 𝔤𝔩(1, 2) and 𝔤𝔩(2, 2), we show that the Pauli and Dirac matrices generate the matrix 3-Lie superalgebras, and we find the non-trivial graded triple commutators of these algebras. We propose a Clifford algebra approach to 3-Lie superalgebras induced by Lie superalgebras. We also discuss an application of matrix 3-Lie superalgebras in BRST-formalism.
Infinite Matrix Products and the Representation of the Matrix Gamma Function
Directory of Open Access Journals (Sweden)
J.-C. Cortés
2015-01-01
Full Text Available We introduce infinite matrix products including some of their main properties and convergence results. We apply them in order to extend to the matrix scenario the definition of the scalar gamma function given by an infinite product due to Weierstrass. A limit representation of the matrix gamma function is also provided.
Block Hadamard measurement matrix with arbitrary dimension in compressed sensing
Liu, Shaoqiang; Yan, Xiaoyan; Fan, Xiaoping; Li, Fei; Xu, Wen
2017-01-01
As Hadamard measurement matrix cannot be used for compressing signals with dimension of a non-integral power-of-2, this paper proposes a construction method of block Hadamard measurement matrix with arbitrary dimension. According to the dimension N of signals to be measured, firstly, construct a set of Hadamard sub matrixes with different dimensions and make the sum of these dimensions equals to N. Then, arrange the Hadamard sub matrixes in a certain order to form a block diagonal matrix. Finally, take the former M rows of the block diagonal matrix as the measurement matrix. The proposed measurement matrix which retains the orthogonality of Hadamard matrix and sparsity of block diagonal matrix has highly sparse structure, simple hardware implements and general applicability. Simulation results show that the performance of our measurement matrix is better than Gaussian matrix, Logistic chaotic matrix, and Toeplitz matrix.
Universal portfolios generated by Vandermonde generating matrix
Tan, Choon Peng; Yong, Say Loong
2017-04-01
A universal portfolio generated by the one-parameter symmetric positive definite Vandermonde matrix is studied. It is obtained by maximizing the scaled growth rate of the estimated daily wealth return and minimizing the Mahalanobis squared divergence of two portfolio vectors associated with the Vandermonde matrix. The parameter of the Vandermonde matrix is chosen so that the matrix is positive definite. The companion matrices of the three and five-dimensional generating matrices are evaluated to determine the portfolios. Three and five stock-data sets are selected from the local stock exchange in Malaysia and the empirical performance of the portfolios is presented. There is empirical evidence that the use of an appropriate generating Vandermonde matrix may increase the wealth of investors.
Nuclear Matrix Proteins in Human Colon Cancer
Keesee, Susan K.; Meneghini, Marc D.; Szaro, Robert P.; Wu, Ying-Jye
1994-03-01
The nuclear matrix is the nonchromatin scaffolding of the nucleus. This structure confers nuclear shape, organizes chromatin, and appears to contain important regulatory proteins. Tissue specific nuclear matrix proteins have been found in the rat, mouse, and human. In this study we compared high-resolution two-dimensional gel electropherograms of nuclear matrix protein patterns found in human colon tumors with those from normal colon epithelia. Tumors were obtained from 18 patients undergoing partial colectomy for adenocarcinoma of the colon and compared with tissue from 10 normal colons. We have identified at least six proteins which were present in 18 of 18 colon tumors and 0 of 10 normal tissues, as well as four proteins present in 0 of 18 tumors and in 10 of 10 normal tissues. These data, which corroborate similar findings of cancer-specific nuclear matrix proteins in prostate and breast, suggest that nuclear matrix proteins may serve as important markers for at least some types of cancer.
Matrix biology: past, present and future.
Robert, L
2001-05-01
Matrix biology (the biology of extracellular matrix) is a relatively recent branch of biomedical sciences and comprises a number of subspecialties. From molecular-cell biology, biochemistry, genetics and clinical science of diseases localised at or affecting the matrix rich tissues (connective tissues) as bone, cartilage, vessel wall, skin, eye and some others. The rapid expansion of all these branches of matrix biology is the combined result of the availability of advanced methods of cell and molecular biology and the increasing awareness of the importance of this field for a number of basic and applied sciences. This introduction is a review for the special issue of Pathologie Biologie devoted to 'Matrix Biology' and brushes an impressionistic landscape of the major advances accomplished over the finishing century and tries to predict some of the most important advances to be expected during the coming century.
Development of a Java Package for Matrix Programming
Lim, Ngee-Peng; Ling, Maurice HT; Lim, Shawn YC; Choi, Ji-Hee; Teo, Henry BK
2003-01-01
We had assembled a Java package, known as MatrixPak, of four classes for the purpose of numerical matrix computation. The classes are matrix, matrix_operations, StrToMatrix, and MatrixToStr; all of which are inherited from java.lang.Object class. Class matrix defines a matrix as a two-dimensional array of float types, and contains the following mathematical methods: transpose, adjoint, determinant, inverse, minor and cofactor. Class matrix_operations contains the following mathematical method...
Nuclear matrix proteins and hereditary diseases.
Sjakste, N; Sjakste, T
2005-03-01
The review summarizes literature data on alterations of structure or expression of different nuclear matrix proteins in hereditary syndromes. From the point of view of involvement of nuclear matrix proteins in etiology and pathogenesis of the disease hereditary pathologies can be classified in pathologies with pathogenesis associated with defects of nuclear matrix proteins and pathologies associated to changes of the nuclear matrix protein spectrum. The first group includes laminopathies, hereditary diseases with abnormal nuclear-matrix associated proteins and triplet extension diseases associated with accumulation of abnormal proteins in the nuclear matrix. Laminopathies are hereditary diseases coupled to structural defects of the nuclear lamina. These diseases include Emery-Dreifuss muscular dystrophy, limb girdle muscular dystrophy, dilated cardiomyopathy (DCM) with conduction system disease, familial partial lipodystrophy (FPLD), autosomal recessive axonal neuropathy (Charcot-Marie-Tooth disorder type 2, CMT2), mandibuloacral dysplasia (MAD), Hutchison Gilford Progeria syndrome (HGS), Greenberg Skeletal Dysplasia, and Pelger-Huet anomaly (PHA). Most of them are due to mutations in the lamin A/C gene, one - to mutations in emerin gene, some are associated with mutations in Lamin B receptor gene. In Werner's, Bloom's, Cockayne's syndromes, Fanconi anemia, multiple carboxylase deficiency mutations in nuclear matrix protein or enzyme gene lead to deficient DNA repair, abnormal regulation of cell growth and differentiation or other specific metabolic functions. Proteins with a long polyglutamic tract synthesized in the cells of patients with dentato-rubral and pallido-luysian atrophy, myotonic dystrophy and Huntington disease interfere with transcription on the nuclear matrix. Down's syndrome is a representative of the group of diseases with altered nuclear matrix protein spectrum.
Inequalities involving upper bounds for certain matrix operators
Indian Academy of Sciences (India)
Copson and Hilbert matrix operators, which are recently considered in [5] and [6] and similar to that in [10]. Keywords. Inequality; norm; summability matrix; Hausdorff matrix; Hilbert matrix; weighted sequence space; Lorentz sequence space. 1. Introduction. We study the norm of a certain matrix operator on lp(w) and Lorentz ...
Residual, restarting and Richardson iteration for the matrix exponential
Bochev, Mikhail A.; Grimm, Volker; Hochbruck, Marlis
2013-01-01
A well-known problem in computing some matrix functions iteratively is the lack of a clear, commonly accepted residual notion. An important matrix function for which this is the case is the matrix exponential. Suppose the matrix exponential of a given matrix times a given vector has to be computed.
Residual, restarting and Richardson iteration for the matrix exponential
Bochev, Mikhail A.
A well-known problem in computing some matrix functions iteratively is a lack of a clear, commonly accepted residual notion. An important matrix function for which this is the case is the matrix exponential. Assume, the matrix exponential of a given matrix times a given vector has to be computed. We
Partial chord diagrams and matrix models
DEFF Research Database (Denmark)
Andersen, Jørgen Ellegaard; Fuji, Hiroyuki; Manabe, Masahide
spectrum. Furthermore, we consider the boundary length and point spectrum that unifies the last two types of spectra. We introduce matrix models that encode generating functions of partial chord diagrams filtered by each of these spectra. Using these matrix models, we derive partial differential equations......In this article, the enumeration of partial chord diagrams is discussed via matrix model techniques. In addition to the basic data such as the number of backbones and chords, we also consider the Euler characteristic, the backbone spectrum, the boundary point spectrum, and the boundary length...
Microlevel thermal effects in metal matrix composites
Herakovich, Carl T.
1990-01-01
A method for studying the influence of thermal effects on the inelastic response of metal matrix composites is reviewed. A micromechanics approach based upon the method of cells is shown to be quite versatile for studying a variety of materials response phenomena. Yielding and inelastic response of the composite are predicted as functions of thermal stresses, yielding of the matrix, and imperfect fiber/matrix bonding. Results are presented in the form of yield surfaces and nonlinear stress-strain curves for unidirectional and laminated boron/aluminum and silicon-carbide/titanium.
Learned fusion operators based on matrix completion
Risko, Kelly K. D.; Hester, Charles F.
2011-05-01
The efficient and timely management of imagery captured in the battlefield requires methods capable of searching the voluminous databases and extracting highly symbolic concepts. When processing images, a semantic and definition gap exists between machine representations and the user's language. Based on matrix completion techniques, we present a fusion operator that fuses imagery and expert knowledge provided by user inputs during post analysis. Specifically, an information matrix is formed from imagery and a class map as labeled by an expert. From this matrix an image operator is derived for the extraction/prediction of information from future imagery. We will present results using this technique on single mode data.
A matrix model from string field theory
Directory of Open Access Journals (Sweden)
Syoji Zeze
2016-09-01
Full Text Available We demonstrate that a Hermitian matrix model can be derived from level truncated open string field theory with Chan-Paton factors. The Hermitian matrix is coupled with a scalar and U(N vectors which are responsible for the D-brane at the tachyon vacuum. Effective potential for the scalar is evaluated both for finite and large N. Increase of potential height is observed in both cases. The large $N$ matrix integral is identified with a system of N ZZ branes and a ghost FZZT brane.
A transilient matrix for moist convection
Energy Technology Data Exchange (ETDEWEB)
Romps, D.; Kuang, Z.
2011-08-15
A method is introduced for diagnosing a transilient matrix for moist convection. This transilient matrix quantifies the nonlocal transport of air by convective eddies: for every height z, it gives the distribution of starting heights z{prime} for the eddies that arrive at z. In a cloud-resolving simulation of deep convection, the transilient matrix shows that two-thirds of the subcloud air convecting into the free troposphere originates from within 100 m of the surface. This finding clarifies which initial height to use when calculating convective available potential energy from soundings of the tropical troposphere.
Generic construction of efficient matrix product operators
Hubig, C.; McCulloch, I. P.; Schollwöck, U.
2017-01-01
Matrix product operators (MPOs) are at the heart of the second-generation density matrix renormalization group (DMRG) algorithm formulated in matrix product state language. We first summarize the widely known facts on MPO arithmetic and representations of single-site operators. Second, we introduce three compression methods (rescaled SVD, deparallelization, and delinearization) for MPOs and show that it is possible to construct efficient representations of arbitrary operators using MPO arithmetic and compression. As examples, we construct powers of a short-ranged spin-chain Hamiltonian, a complicated Hamiltonian of a two-dimensional system and, as proof of principle, the long-range four-body Hamiltonian from quantum chemistry.
Celsian Glass-Ceramic Matrix Composites
Bansal, Narottam P.; Dicarlo, James A.
1996-01-01
Glass-ceramic matrix reinforced fiber composite materials developed for use in low dielectric applications, such as radomes. Materials strong and tough, exhibit low dielectric properties, and endure high temperatures.
Enzyme compartmentalization during biphasic enamel matrix processing.
Brookes, S J; Kirkham, J; Shore, R C; Bonass, W A; Robinson, C
1998-01-01
Processing of enamel matrix proteins is essentially biphasic. Secretory stage metalloprotease activity generates a discrete, presumably functional, spectrum of molecules which may also undergo dephosphorylation. Maturation stage serine proteases almost completely destroy the matrix. The present aim was to examine the tissue compartmentalization of these enzyme activities in relation to their possible function. A sequential extraction using synthetic enamel fluid, phosphate buffer and SDS was used to identify enzymes free in the enamel fluid, crystal bound or aggregated with the bulk matrix respectively. Results indicated that the metallo-proteases and alkaline phosphatase were free in the secretory stage enamel fluid while the serine proteases appeared to be largely bound to the maturation stage crystals. The mobility of the metallo-proteases and alkaline phosphatase would ensure efficient initial processing of secretory matrix, while the largely mineral bound serine proteases would ensure retention of protease activity despite massive destruction and protein removal.
Nuclear waste storage container with metal matrix
Sump, Kenneth R.
1978-01-01
The invention relates to a storage container for high-level waste having a metal matrix for the high-level waste, thereby providing greater impact strength for the waste container and increasing heat transfer properties.
Development of a Compact Matrix Converter
Directory of Open Access Journals (Sweden)
J. Bauer
2009-01-01
Full Text Available This paper deals with the development of a matrix converter. Matrix converters belong to the category of direct frequency converters. A converter does not contain DC-link and the output voltage is provided by direct switching of voltage from the input phases. This is enabled by 9 bidirectional switches, which are provided by anti-serial connection of 18 IGBT transistors. The absence of a DC-link is great advantage of the matrix converter, but it also increases the requirements on the converter control. For this reason a new prototype of a matrix converter is being developed with sophisticated modern components (FPGA, Power PC equipped in the control part of the converter. The converter will be used for testing new control algorithms and commutation methods.
Association between the polymorphisms of matrix ...
African Journals Online (AJOL)
Association between the polymorphisms of matrix metalloproteinases 9 and 3 genes and risk of myocardial infarction in Egyptian patients. Nadia I Sewelam, Eman R Radwan, Ashraf W Andraos, Baher E Ibrahim, Manal M Wilson ...
Design of lipid matrix particles for fenofibrate
DEFF Research Database (Denmark)
Xia, Dengning; Cui, Fude; Gan, Yong
2014-01-01
The effect of polymorphism of glycerol monostearate (GMS) on drug incorporation and release from lipid matrix particles (LMPs) was investigated using fenofibrate as a model drug. X-ray powder diffraction and differential scanning calorimetry were used to study the polymorphism change of GMS...... and the drug incorporation in GMS matrix. When medium-chain triglycerides (MCT) was absent, melted GMS was frozen to α-form of GMS with drug molecularly dispersed, whereas β-form of GMS was formed with part of drug crystallized out when the ratio of GMS/MCT in the lipid matrix was 2:1 (w/w). For LMP composed......, the polymorphism of GMS is an important factor determining particle stability, drug incorporation, and the release of the drug from LMP. Critical attention should be paid on the investigation as well as control of the lipid polymorphism when formulating lipid-based matrix particles. © 2013 Wiley Periodicals, Inc...
Supersymmetric SYK model and random matrix theory
Li, Tianlin; Liu, Junyu; Xin, Yuan; Zhou, Yehao
2017-06-01
In this paper, we investigate the effect of supersymmetry on the symmetry classification of random matrix theory ensembles. We mainly consider the random matrix behaviors in the N=1 supersymmetric generalization of Sachdev-Ye-Kitaev (SYK) model, a toy model for two-dimensional quantum black hole with supersymmetric constraint. Some analytical arguments and numerical results are given to show that the statistics of the supersymmetric SYK model could be interpreted as random matrix theory ensembles, with a different eight-fold classification from the original SYK model and some new features. The time-dependent evolution of the spectral form factor is also investigated, where predictions from random matrix theory are governing the late time behavior of the chaotic hamiltonian with supersymmetry.
Research on Radar Importance with Decision Matrix
Meng, Lingjie; Du, Yu; Wang, Liuheng
2017-12-01
Considering the characteristic of radar, constructed the evaluation index system of radar importance, established the comprehensive evaluation model based on decision matrix. Finally, by means of an example, the methods of this evaluation on radar importance was right and feasibility.
Microwave Processed Multifunctional Polymer Matrix Composites Project
National Aeronautics and Space Administration — NASA has identified polymer matrix composites (PMCs) as a critical need for launch and in-space vehicles, but the significant costs of such materials limits their...
A matrix of social accounting for Asturias
Directory of Open Access Journals (Sweden)
Margarita Argüelles
2003-01-01
Full Text Available A Social Accounting Matrix is an integrated system of accounts that presents in a double-entry table all the transactions made in an economy among productive sectors, production factors, institutional sectors and the rest of the world. In comparison with an Input-Output Table, it offers a greater deal of information and shows completely the circular process of income, captivating more precisely the effects of exogenous changes. One of the main profits of a Social Accounting Matrix is to serve as a database for the development and application of a computable general equilibrium model. This is, in fact, the aim pursued with the elaboration of the Social Accounting Matrix for the Asturian economy presented here. This Matrix has been constructed with data from the 1995 Regional Accounts of Asturias, and its structure has been adapted to its future use as a database for a computable general equilibrium model of this regional economy.
Matrix-exponential distributions in applied probability
Bladt, Mogens
2017-01-01
This book contains an in-depth treatment of matrix-exponential (ME) distributions and their sub-class of phase-type (PH) distributions. Loosely speaking, an ME distribution is obtained through replacing the intensity parameter in an exponential distribution by a matrix. The ME distributions can also be identified as the class of non-negative distributions with rational Laplace transforms. If the matrix has the structure of a sub-intensity matrix for a Markov jump process we obtain a PH distribution which allows for nice probabilistic interpretations facilitating the derivation of exact solutions and closed form formulas. The full potential of ME and PH unfolds in their use in stochastic modelling. Several chapters on generic applications, like renewal theory, random walks and regenerative processes, are included together with some specific examples from queueing theory and insurance risk. We emphasize our intention towards applications by including an extensive treatment on statistical methods for PH distribu...
Superfund Chemical Data Matrix (SCDM) Query
This site allows you to to easily query the Superfund Chemical Data Matrix (SCDM) and generate a list of the corresponding Hazard Ranking System (HRS) factor values, benchmarks, and data elements that you need.
Superfund Chemical Data Matrix (SCDM) Query - Popup
This site allows you to to easily query the Superfund Chemical Data Matrix (SCDM) and generate a list of the corresponding Hazardous Ranking System (HRS) factor values, benchmarks, and data elements that you need.
Comix, a new matrix element generator
Gleisberg, Tanju; Höche, Stefan
2008-12-01
We present a new tree-level matrix element generator, based on the colour dressed Berends-Giele recursive relations. We discuss two new algorithms for phase space integration, dedicated to be used with large multiplicities and colour sampling.
CERN. Geneva
2016-01-01
In this talk I will describe recent work aiming to reinvigorate the 50 year old S-matrix program, which aims to constrain scattering of massive particles non-perturbatively. I will begin by considering quantum fields in anti-de Sitter space and show that one can extract information about the S-matrix by considering correlators in conformally invariant theories. The latter can be studied with "bootstrap" techniques, which allow us to constrain the S-matrix. In particular, in 1+1D one obtains bounds which are saturated by known integrable models. I will also show that it is also possible to directly constrain the S-matrix, without using the CFT crutch, by using crossing symmetry and unitarity. This alternative method is simpler and gives results in agreement with the previous approach. Both techniques are generalizable to higher dimensions.
Applied matrix algebra in the statistical sciences
Basilevsky, Alexander
2005-01-01
This comprehensive text offers teachings relevant to both applied and theoretical branches of matrix algebra and provides a bridge between linear algebra and statistical models. Appropriate for advanced undergraduate and graduate students. 1983 edition.
GB Diet matrix as informed by EMAX
National Oceanic and Atmospheric Administration, Department of Commerce — This data set was taken from CRD 08-18 at the NEFSC. Specifically, the Georges Bank diet matrix was developed for the EMAX exercise described in that center...
Extracellular matrix component signaling in cancer
DEFF Research Database (Denmark)
Multhaupt, Hinke A. B.; Leitinger, Birgit; Gullberg, Donald
2016-01-01
Cell responses to the extracellular matrix depend on specific signaling events. These are important from early development, through differentiation and tissue homeostasis, immune surveillance, and disease pathogenesis. Signaling not only regulates cell adhesion cytoskeletal organization...... and motility but also provides survival and proliferation cues. The major classes of cell surface receptors for matrix macromols. are the integrins, discoidin domain receptors, and transmembrane proteoglycans such as syndecans and CD44. Cells respond not only to specific ligands, such as collagen, fibronectin......, or basement membrane glycoproteins, but also in terms of matrix rigidity. This can regulate the release and subsequent biol. activity of matrix-bound growth factors, for example, transforming growth factor-β. In the environment of tumors, there may be changes in cell populations and their receptor profiles...
Study of theophylline stability on polymer matrix
Energy Technology Data Exchange (ETDEWEB)
Rodrigues, Kiriaki M.S.; Parra, Duclerc F.; Oliveira, Maria Jose A.; Bustillos, Oscar V.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], E-mail: strassacapa@uol.com.br
2007-07-01
Theophylline is a bronchodilator, commonly known and used as a drug model in the development of pharmaceutical formulations. The stability of the drug and the matrix, scope of this study, was evaluated in the solid formulation. Polymeric matrix based on PHB containing the drug (theophylline) was prepared and submitted to radiation sterilization at different doses of: 5, 10, 20 and 25 kGy using a Cobalt- 60 source. The modified drug release of theophylline sterilized tablets has been studied. Modern techniques of HPLC (High Pressure Liquid Chromatography), DSC (Differential scanning calorimetry) and TGA (Thermogravimetry analysis) were employed. The results have shown the influence of sterilization by radiation process in both the theophylline and the polymeric drug delivery matrix samples. The increasing of polymeric matrix crosslinking under radiation conditions retards the drug release while the theophylline structure is stable under the radiation (author)
Contact matrix in dilute quantum systems
Zhang, Shao-Liang; He, Mingyuan; Zhou, Qi
2017-06-01
Contact has been well established as an important quantity to govern dilute quantum systems, in which the pairwise correlation at short distance traces a broad range of thermodynamic properties. So far, most studies have focused on contact in individual angular momentum channels. Here we point out that, to have a complete description of the pairwise correlation in a general dilute quantum systems, contact should be defined as a matrix. Whereas the diagonal terms of such a matrix include contact of all partial wave scatterings, the off-diagonal terms characterize the coherence of the asymptotic pairwise wave function in the angular momentum space and determine important thermodynamic quantities including the momentum distribution. The contact matrix allows physicists to access unexplored connections between short-range correlations and macroscopic quantum phenomena. As an example, we show the direct connection between the contact matrix and order parameters of a superfluid with mixed partial waves.
Gu, Xiaojun; Zhang, Weihong; Zaki, Wael; Moumni, Ziad
2017-09-01
The model presented in this paper was shown to successfully account for cyclic loading effects and thermomechanical coupling in SMAs, including the influence of load rate and temperature on both the rate and value at saturation of the residual strain. It is the first such comprehensive model to be successfully utilized for relatively complex simulations involving SMAs subjected to multiaxial nonproportional loading, which possibly result in strong stress gradients such as fracture mechanics. In fact, it is known that the high stress concentration at the tip of a crack in SMAs results in increased martensite transformation and reorientation, which influence the growth of the crack. The derivation of the constitutive equations as well as the time integration and relevant algorithmic considerations are presented in detail. The model was shown to allow reasonable agreement with several sets of reference experimental and simulation data taken from the literature.
Matrix parameters and storage conditions of manure
Energy Technology Data Exchange (ETDEWEB)
Weinfurtner, Karlheinz [Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schmallenberg (Germany)
2011-01-15
The literature study presents an overview of storage conditions for manure and information about important matrix parameters of manure such as dry matter content, pH value, total organic carbon, total nitrogen and ammonium nitrogen. The presented results show that for matrix parameters a dissimilarity of cattle and pig manure can be observed but no difference within the species for different production types occurred with exception of calves. A scenario for western and central European countries is derived. (orig.)
Semisupervised kernel matrix learning by kernel propagation.
Hu, Enliang; Chen, Songcan; Zhang, Daoqiang; Yin, Xuesong
2010-11-01
The goal of semisupervised kernel matrix learning (SS-KML) is to learn a kernel matrix on all the given samples on which just a little supervised information, such as class label or pairwise constraint, is provided. Despite extensive research, the performance of SS-KML still leaves some space for improvement in terms of effectiveness and efficiency. For example, a recent pairwise constraints propagation (PCP) algorithm has formulated SS-KML into a semidefinite programming (SDP) problem, but its computation is very expensive, which undoubtedly restricts PCPs scalability in practice. In this paper, a novel algorithm, called kernel propagation (KP), is proposed to improve the comprehensive performance in SS-KML. The main idea of KP is first to learn a small-sized sub-kernel matrix (named seed-kernel matrix) and then propagate it into a larger-sized full-kernel matrix. Specifically, the implementation of KP consists of three stages: 1) separate the supervised sample (sub)set X(l) from the full sample set X; 2) learn a seed-kernel matrix on X(l) through solving a small-scale SDP problem; and 3) propagate the learnt seed-kernel matrix into a full-kernel matrix on X . Furthermore, following the idea in KP, we naturally develop two conveniently realizable out-of-sample extensions for KML: one is batch-style extension, and the other is online-style extension. The experiments demonstrate that KP is encouraging in both effectiveness and efficiency compared with three state-of-the-art algorithms and its related out-of-sample extensions are promising too.
Micromechanical Modeling of Woven Metal Matrix Composites
Bednarcyk, Brett A.; Pindera, Marek-Jerzy
1997-01-01
This report presents the results of an extensive micromechanical modeling effort for woven metal matrix composites. The model is employed to predict the mechanical response of 8-harness (8H) satin weave carbon/copper (C/Cu) composites. Experimental mechanical results for this novel high thermal conductivity material were recently reported by Bednarcyk et al. along with preliminary model results. The micromechanics model developed herein is based on an embedded approach. A micromechanics model for the local (micro-scale) behavior of the woven composite, the original method of cells (Aboudi), is embedded in a global (macro-scale) micromechanics model (the three-dimensional generalized method of cells (GMC-3D) (Aboudi). This approach allows representation of true repeating unit cells for woven metal matrix composites via GMC-3D, and representation of local effects, such as matrix plasticity, yarn porosity, and imperfect fiber-matrix bonding. In addition, the equations of GMC-3D were reformulated to significantly reduce the number of unknown quantities that characterize the deformation fields at the microlevel in order to make possible the analysis of actual microstructures of woven composites. The resulting micromechanical model (WCGMC) provides an intermediate level of geometric representation, versatility, and computational efficiency with respect to previous analytical and numerical models for woven composites, but surpasses all previous modeling work by allowing the mechanical response of a woven metal matrix composite, with an elastoplastic matrix, to be examined for the first time. WCGMC is employed to examine the effects of composite microstructure, porosity, residual stresses, and imperfect fiber-matrix bonding on the predicted mechanical response of 8H satin C/Cu. The previously reported experimental results are summarized, and the model predictions are compared to monotonic and cyclic tensile and shear test data. By considering appropriate levels of porosity
Ubiquitination of specific mitochondrial matrix proteins
Energy Technology Data Exchange (ETDEWEB)
Lehmann, Gilad [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Ziv, Tamar [The Smoler Proteomics Center, Faculty of Biology – Technion-Israel Institute of Technology, Haifa, 32000 (Israel); Braten, Ori [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Admon, Arie [The Smoler Proteomics Center, Faculty of Biology – Technion-Israel Institute of Technology, Haifa, 32000 (Israel); Udasin, Ronald G. [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Ciechanover, Aaron, E-mail: aaroncie@tx.technion.ac.il [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel)
2016-06-17
Several protein quality control systems in bacteria and/or mitochondrial matrix from lower eukaryotes are absent in higher eukaryotes. These are transfer-messenger RNA (tmRNA), The N-end rule ATP-dependent protease ClpAP, and two more ATP-dependent proteases, HslUV and ClpXP (in yeast). The lost proteases resemble the 26S proteasome and the role of tmRNA and the N-end rule in eukaryotic cytosol is performed by the ubiquitin proteasome system (UPS). Therefore, we hypothesized that the UPS might have substituted these systems – at least partially – in the mitochondrial matrix of higher eukaryotes. Using three independent experimental approaches, we demonstrated the presence of ubiquitinated proteins in the matrix of isolated yeast mitochondria. First, we show that isolated mitochondria contain ubiquitin (Ub) conjugates, which remained intact after trypsin digestion. Second, we demonstrate that the mitochondrial soluble fraction contains Ub-conjugates, several of which were identified by mass spectrometry and are localized to the matrix. Third, using immunoaffinity enrichment by specific antibodies recognizing digested ubiquitinated peptides, we identified a group of Ub-modified matrix proteins. The modification was further substantiated by separation on SDS-PAGE and immunoblots. Last, we attempted to identify the ubiquitin ligase(s) involved, and identified Dma1p as a trypsin-resistant protein in our mitochondrial preparations. Taken together, these data suggest a yet undefined role for the UPS in regulation of the mitochondrial matrix proteins. -- Highlights: •Mitochondrial matrix contains ubiquitinated proteins. •Ubiquitination occurs most probably in the matrix. •Dma1p is a ubiquitin ligase present in mitochondrial preparations.
Data from acellular human heart matrix
Sánchez, Pedro L; Fernández-Santos, Mª Eugenia; Espinosa, Mª Angeles; González-Nicolas, Mª Angeles; Acebes, Judith R; Costanza, Salvatore; Moscoso, Isabel; Rodríguez, Hugo; García, Julio; Romero, Jesús; Kren, Stefan M; Bermejo, Javier; Yotti, Raquel; del Villar, Candelas Pérez; Sanz-Ruiz, Ricardo
2016-01-01
Perfusion decellularization of cadaveric hearts removes cells and generates a cell-free extracellular matrix scaffold containing acellular vascular conduits, which are theoretically sufficient to perfuse and support tissue-engineered heart constructs. This article contains additional data of our experience decellularizing and testing structural integrity and composition of a large series of human hearts, “Acellular human heart matrix: a critical step toward whole heat grafts” (Sanchez et al.,...
Quantized Matrix Algebras and Quantum Seeds
DEFF Research Database (Denmark)
Jakobsen, Hans Plesner; Pagani, Chiara
2015-01-01
We determine explicitly quantum seeds for classes of quantized matrix algebras. Furthermore, we obtain results on centres and block diagonal forms of these algebras. In the case where is an arbitrary root of unity, this further determines the degrees.......We determine explicitly quantum seeds for classes of quantized matrix algebras. Furthermore, we obtain results on centres and block diagonal forms of these algebras. In the case where is an arbitrary root of unity, this further determines the degrees....
Recursive Approach in Sparse Matrix LU Factorization
Directory of Open Access Journals (Sweden)
Jack Dongarra
2001-01-01
Full Text Available This paper describes a recursive method for the LU factorization of sparse matrices. The recursive formulation of common linear algebra codes has been proven very successful in dense matrix computations. An extension of the recursive technique for sparse matrices is presented. Performance results given here show that the recursive approach may perform comparable to leading software packages for sparse matrix factorization in terms of execution time, memory usage, and error estimates of the solution.
Embedded Lattice and Properties of Gram Matrix
Directory of Open Access Journals (Sweden)
Futa Yuichi
2017-03-01
Full Text Available In this article, we formalize in Mizar [14] the definition of embedding of lattice and its properties. We formally define an inner product on an embedded module. We also formalize properties of Gram matrix. We formally prove that an inverse of Gram matrix for a rational lattice exists. Lattice of Z-module is necessary for lattice problems, LLL (Lenstra, Lenstra and Lov´asz base reduction algorithm [16] and cryptographic systems with lattice [17].
Index matrices towards an augmented matrix calculus
Atanassov, Krassimir T
2014-01-01
This book presents the very concept of an index matrix and its related augmented matrix calculus in a comprehensive form. It mostly illustrates the exposition with examples related to the generalized nets and intuitionistic fuzzy sets which are examples of an extremely wide array of possible application areas. The present book contains the basic results of the author over index matrices and some of its open problems with the aim to stimulating more researchers to start working in this area.
Polymer Matrix Composite Material Oxygen Compatibility
Owens, Tom
2001-01-01
Carbon fiber/polymer matrix composite materials look promising as a material to construct liquid oxygen (LOX) tanks. Based on mechanical impact tests the risk will be greater than aluminum, however, the risk can probably be managed to an acceptable level. Proper tank design and operation can minimize risk. A risk assessment (hazard analysis) will be used to determine the overall acceptability for using polymer matrix composite materials.
Semiclassical form factor of matrix element fluctuations
Eckhardt, B; Eckhardt, Bruno; Main, Joerg
1995-01-01
We analyze within a semiclassical approximation the form factor for the fluctuations of quantum matrix elements around their classical average. We find two contributions: one is proportional to the form factor for the density of states, with an amplitude determined by the squared average of the matrix elements. The other is constant and related to the fluctuations of finite time classical trajectory segments around the phase space average. The results are illustrated for an observable in the quadratic Zeeman effect.
TOTAL HARMONIC DISTORTION ANALYSIS OF MATRIX CONVERTER
K. Kandan; Senthilkumar,K.; Dhivya, K.
2016-01-01
This paper deals with the validation and design analysis of Matrix converter for variable frequency using mathematical equations. The analysis was done using Venturini modulation algorithm. The PI controller is used for Matrix converter to reduce Total Harmonic Distortion (THD) in the output current. The comparative study is done for open loop and closed loop PI compensation in MATLAB-Simulink. Furthermore, the output waveforms are produced with significant reduction in the Total Harmonic Dis...
Spectral clustering based on learning similarity matrix.
Park, Seyoung; Zhao, Hongyu; Birol, Inanc
2018-02-08
Single-cell RNA-sequencing (scRNA-seq) technology can generate genome-wide expression data at the single-cell levels. One important objective in scRNA-seq analysis is to cluster cells where each cluster consists of cells belonging to the same cell type based on gene expression patterns. We introduce a novel spectral clustering framework that imposes sparse structures on a target matrix. Specifically, we utilize multiple doubly stochastic similarity matrices to learn a similarity matrix, motivated by the observation that each similarity matrix can be a different informative representation of the data. We impose a sparse structure on the target matrix followed by shrinking pairwise differences of the rows in the target matrix, motivated by the fact that the target matrix should have these structures in the ideal case. We solve the proposed non-convex problem iteratively using the ADMM algorithm and show the convergence of the algorithm. We evaluate the performance of the proposed clustering method on various simulated as well as real scRNA-seq data, and show that it can identify clusters accurately and robustly. The algorithm is implemented in MATLAB. The source code can be downloaded at https://github.com/ishspsy/project/tree/master/MPSSC. seyoung.park@yale.edu. Supplementary data are available at Bioinformatics online.
Superficial Siderosis after Germinal Matrix Hemorrhage.
Yilmaz, U; Meyer, S; Gortner, L; Körner, H; Türkyilmaz, M; Simgen, A; Reith, W; Mühl-Benninghaus, R
2016-12-01
Germinal matrix hemorrhage is a frequent complication of prematurity and can be associated with adverse neurodevelopmental outcome, depending on its severity. In addition to parenchymal damage, intraventricular residues of hemorrhage and hydrocephalus MR imaging findings include superficial siderosis. The purpose of this study was to investigate the prevalence and location of superficial siderosis in patients with a history of germinal matrix hemorrhage. We retrospectively identified patients with a history of germinal matrix hemorrhage who underwent MR imaging in our institution between 2008 and 2016. Imaging was evaluated for the presence and location of superficial siderosis. The presence of subependymal siderosis and evidence of hydrocephalus were assessed. Thirty-seven patients with a history of germinal matrix hemorrhage were included; 86.5% had preterm births. The mean age at the first MR imaging was 386 days (range 2-5140 days). The prevalence of superficial siderosis was 67.6%. Superficial siderosis was detected significantly more often when MR imaging was performed within the first year of life (82.8% versus 12.5%, P germinal matrix hemorrhage, but it dissolves and has a low prevalence thereafter. A prospective analysis of its initial severity and speed of dissolution during this first year might add to our understanding of the pathophysiology of neurodevelopmental impairment after germinal matrix hemorrhages. © 2016 by American Journal of Neuroradiology.
Matrix method for acoustic levitation simulation.
Andrade, Marco A B; Perez, Nicolas; Buiochi, Flavio; Adamowski, Julio C
2011-08-01
A matrix method is presented for simulating acoustic levitators. A typical acoustic levitator consists of an ultrasonic transducer and a reflector. The matrix method is used to determine the potential for acoustic radiation force that acts on a small sphere in the standing wave field produced by the levitator. The method is based on the Rayleigh integral and it takes into account the multiple reflections that occur between the transducer and the reflector. The potential for acoustic radiation force obtained by the matrix method is validated by comparing the matrix method results with those obtained by the finite element method when using an axisymmetric model of a single-axis acoustic levitator. After validation, the method is applied in the simulation of a noncontact manipulation system consisting of two 37.9-kHz Langevin-type transducers and a plane reflector. The manipulation system allows control of the horizontal position of a small levitated sphere from -6 mm to 6 mm, which is done by changing the phase difference between the two transducers. The horizontal position of the sphere predicted by the matrix method agrees with the horizontal positions measured experimentally with a charge-coupled device camera. The main advantage of the matrix method is that it allows simulation of non-symmetric acoustic levitators without requiring much computational effort.
Fast matrix multiplication and its algebraic neighbourhood
Pan, V. Ya.
2017-11-01
Matrix multiplication is among the most fundamental operations of modern computations. By 1969 it was still commonly believed that the classical algorithm was optimal, although the experts already knew that this was not so. Worldwide interest in matrix multiplication instantly exploded in 1969, when Strassen decreased the exponent 3 of cubic time to 2.807. Then everyone expected to see matrix multiplication performed in quadratic or nearly quadratic time very soon. Further progress, however, turned out to be capricious. It was at stalemate for almost a decade, then a combination of surprising techniques (completely independent of Strassen's original ones and much more advanced) enabled a new decrease of the exponent in 1978–1981 and then again in 1986, to 2.376. By 2017 the exponent has still not passed through the barrier of 2.373, but most disturbing was the curse of recursion — even the decrease of exponents below 2.7733 required numerous recursive steps, and each of them squared the problem size. As a result, all algorithms supporting such exponents supersede the classical algorithm only for inputs of immense sizes, far beyond any potential interest for the user. We survey the long study of fast matrix multiplication, focusing on neglected algorithms for feasible matrix multiplication. We comment on their design, the techniques involved, implementation issues, the impact of their study on the modern theory and practice of Algebraic Computations, and perspectives for fast matrix multiplication. Bibliography: 163 titles.
Genetic Relationships Between Chondrules, Rims and Matrix
Huss, G. R.; Alexander, C. M. OD.; Palme, H.; Bland, P. A.; Wasson, J. T.
2004-01-01
The most primitive chondrites are composed of chondrules and chondrule fragments, various types of inclusions, discrete mineral grains, metal, sulfides, and fine-grained materials that occur as interchondrule matrix and as chondrule/inclusion rims. Understanding how these components are related is essential for understanding how chondrites and their constituents formed and were processed in the solar nebula. For example, were the first generations of chondrules formed by melting of matrix or matrix precursors? Did chondrule formation result in appreciable transfer of chondrule material into the matrix? Here, we consider three types of data: 1) compositional data for bulk chondrites and matrix, 2) mineralogical and textural information, and 3) the abundances and characteristics of presolar materials that reside in the matrix and rims. We use these data to evaluate the roles of evaporation and condensation, chondrule formation, mixing of different nebular components, and secondary processing both in the nebula and on the parent bodies. Our goal is to identify the things that are reasonably well established and to point out the areas that need additional work.
Multi-threaded Sparse Matrix Sparse Matrix Multiplication for Many-Core and GPU Architectures.
Energy Technology Data Exchange (ETDEWEB)
Deveci, Mehmet [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Trott, Christian Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rajamanickam, Sivasankaran [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2018-01-01
Sparse Matrix-Matrix multiplication is a key kernel that has applications in several domains such as scientific computing and graph analysis. Several algorithms have been studied in the past for this foundational kernel. In this paper, we develop parallel algorithms for sparse matrix- matrix multiplication with a focus on performance portability across different high performance computing architectures. The performance of these algorithms depend on the data structures used in them. We compare different types of accumulators in these algorithms and demonstrate the performance difference between these data structures. Furthermore, we develop a meta-algorithm, kkSpGEMM, to choose the right algorithm and data structure based on the characteristics of the problem. We show performance comparisons on three architectures and demonstrate the need for the community to develop two phase sparse matrix-matrix multiplication implementations for efficient reuse of the data structures involved.
Method of producing a hybrid matrix fiber composite
Deteresa, Steven J [Livermore, CA; Lyon, Richard E [Absecon, NJ; Groves, Scott E [Brentwood, CA
2006-03-28
Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites comprised of two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.
Method of forming a ceramic matrix composite and a ceramic matrix component
de Diego, Peter; Zhang, James
2017-05-30
A method of forming a ceramic matrix composite component includes providing a formed ceramic member having a cavity, filling at least a portion of the cavity with a ceramic foam. The ceramic foam is deposited on a barrier layer covering at least one internal passage of the cavity. The method includes processing the formed ceramic member and ceramic foam to obtain a ceramic matrix composite component. Also provided is a method of forming a ceramic matrix composite blade and a ceramic matrix composite component.
Energy Technology Data Exchange (ETDEWEB)
Olier, P.
1996-12-31
In order to promote the development of Ti-Ni shape memory alloys, we have studied the correlation between the fabrication route, the chemical composition (O{sub 2} content, Zr or Hf additions), the metallurgical characteristics and the thermomechanical properties. A conventional sintering does not allow to obtain a homogeneous compound of pure Ti{sub 50}Ni{sub 50} alloy because of the occurrence of Kirkendall porosities which act as a diffusion barrier. An original process including combustion synthesis and hot-extrusion was successfully developed. Resulting products exhibit a smaller grain size (15-20{mu}m) and an enhanced workability in comparison with products obtained by arc-melting and subsequent hot rolling. The presence of oxygen in equiatomic Ti-Ni alloy induces the oxide precipitation of Ti{sub 4}Ni{sub 2}O{sub x} type (with x {<=} 1). The precipitated particle fraction is proportional to the oxygen nominal content of the alloy. We show that the decrease of the transformation temperatures is correlated with the decrease of Ti in solid solution due to Ti{sub 4}Ni{sub 2}O precipitation. Moreover, we find that a fine and homogenous oxide dispersion is suitable to decrease the grain size during hot rolling and to enhance to the one way shape memory properties. An increase of the typical transformation temperatures is obtained through of Zr or Hf (in substitution to Ti). But, an increase of the hardness is measured, and consequently the workability of the ternary alloys becomes reduced. However, it is worthwhile to point out that a Ti{sub 38}Ni{sub 50}Hf{sub 12} product obtained by arc melting and hot extrusion is able to fully recover an apparent plastic strain of more than 4% during tensile tests performed under special loading conditions. Such as behaviour is of great interest with respect to potential applications in a temperature range higher that 100 deg. C. (author). 105 refs.
Energy Technology Data Exchange (ETDEWEB)
Oestberg, Sara, E-mail: sara.ostberg@imbim.uu.se [Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, 75123 Uppsala (Sweden); Toermaenen Persson, Heidi, E-mail: heidi.tormanen.persson@imbim.uu.se [Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, 75123 Uppsala (Sweden); Akusjaervi, Goeran, E-mail: goran.akusjarvi@imbim.uu.se [Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, 75123 Uppsala (Sweden)
2012-11-25
The adenovirus L4-33K protein is a key regulator involved in the temporal shift from early to late pattern of mRNA expression from the adenovirus major late transcription unit. L4-33K is a virus-encoded alternative splicing factor, which enhances processing of 3 Prime splice sites with a weak sequence context. Here we show that L4-33K expressed from a plasmid is localized at the nuclear margin of uninfected cells. During an infection L4-33K is relocalized to the periphery of E2A-72K containing viral replication centers. We also show that serine 192 in the tiny RS repeat of the conserved carboxy-terminus of L4-33K, which is critical for the splicing enhancer function of L4-33K, is necessary for the nuclear localization and redistribution of the protein to viral replication sites. Collectively, our results show a good correlation between the activity of L4-33K as a splicing enhancer protein and its localization to the periphery of viral replication centers.
Google matrix analysis of DNA sequences.
Kandiah, Vivek; Shepelyansky, Dima L
2013-01-01
For DNA sequences of various species we construct the Google matrix [Formula: see text] of Markov transitions between nearby words composed of several letters. The statistical distribution of matrix elements of this matrix is shown to be described by a power law with the exponent being close to those of outgoing links in such scale-free networks as the World Wide Web (WWW). At the same time the sum of ingoing matrix elements is characterized by the exponent being significantly larger than those typical for WWW networks. This results in a slow algebraic decay of the PageRank probability determined by the distribution of ingoing elements. The spectrum of [Formula: see text] is characterized by a large gap leading to a rapid relaxation process on the DNA sequence networks. We introduce the PageRank proximity correlator between different species which determines their statistical similarity from the view point of Markov chains. The properties of other eigenstates of the Google matrix are also discussed. Our results establish scale-free features of DNA sequence networks showing their similarities and distinctions with the WWW and linguistic networks.
Google matrix analysis of DNA sequences.
Directory of Open Access Journals (Sweden)
Vivek Kandiah
Full Text Available For DNA sequences of various species we construct the Google matrix [Formula: see text] of Markov transitions between nearby words composed of several letters. The statistical distribution of matrix elements of this matrix is shown to be described by a power law with the exponent being close to those of outgoing links in such scale-free networks as the World Wide Web (WWW. At the same time the sum of ingoing matrix elements is characterized by the exponent being significantly larger than those typical for WWW networks. This results in a slow algebraic decay of the PageRank probability determined by the distribution of ingoing elements. The spectrum of [Formula: see text] is characterized by a large gap leading to a rapid relaxation process on the DNA sequence networks. We introduce the PageRank proximity correlator between different species which determines their statistical similarity from the view point of Markov chains. The properties of other eigenstates of the Google matrix are also discussed. Our results establish scale-free features of DNA sequence networks showing their similarities and distinctions with the WWW and linguistic networks.
Image encryption using the Sudoku matrix
Wu, Yue; Zhou, Yicong; Noonan, Joseph P.; Panetta, Karen; Agaian, Sos
2010-04-01
This paper introduces a new effective and lossless image encryption algorithm using a Sudoku Matrix to scramble and encrypt the image. The new algorithm encrypts an image through a three stage process. In the first stage, a reference Sudoku matrix is generated as the foundation for the encryption and scrambling processes. The image pixels' intensities are then changed by using the reference Sudoku matrix values, and then the pixels' positions are shuffled using the Sudoku matrix as a mapping process. The advantages of this method is useful for efficiently encrypting a variety of digital images, such as binary images, gray images, and RGB images without any quality loss. The security keys of the presented algorithm are the combination of the parameters in a 1D chaotic logistic map, a parameter to control the size of Sudoku Matrix and the number of iteration times desired for scrambling. The possible security key space is extremely large. The principles of the presented scheme could be applied to provide security for a variety of systems including image, audio and video systems.
Thermal stress effects in intermetallic matrix composites
Wright, P. K.; Sensmeier, M. D.; Kupperman, D. S.; Wadley, H. N. G.
1993-01-01
Intermetallic matrix composites develop residual stresses from the large thermal expansion mismatch (delta-alpha) between the fibers and matrix. This work was undertaken to: establish improved techniques to measure these thermal stresses in IMC's; determine residual stresses in a variety of IMC systems by experiments and modeling; and, determine the effect of residual stresses on selected mechanical properties of an IMC. X ray diffraction (XRD), neutron diffraction (ND), synchrotron XRD (SXRD), and ultrasonics (US) techniques for measuring thermal stresses in IMC were examined and ND was selected as the most promising technique. ND was demonstrated on a variety of IMC systems encompassing Ti- and Ni-base matrices, SiC, W, and Al2O3 fibers, and different fiber fractions (Vf). Experimental results on these systems agreed with predictions of a concentric cylinder model. In SiC/Ti-base systems, little yielding was found and stresses were controlled primarily by delta-alpha and Vf. In Ni-base matrix systems, yield strength of the matrix and Vf controlled stress levels. The longitudinal residual stresses in SCS-6/Ti-24Al-llNb composite were modified by thermomechanical processing. Increasing residual stress decreased ultimate tensile strength in agreement with model predictions. Fiber pushout strength showed an unexpected inverse correlation with residual stress. In-plane shear yield strength showed no dependence on residual stress. Higher levels of residual tension led to higher fatigue crack growth rates, as suggested by matrix mean stress effects.
Random matrix theory and symmetric spaces
Energy Technology Data Exchange (ETDEWEB)
Caselle, M.; Magnea, U
2004-05-01
In this review we discuss the relationship between random matrix theories and symmetric spaces. We show that the integration manifolds of random matrix theories, the eigenvalue distribution, and the Dyson and boundary indices characterizing the ensembles are in strict correspondence with symmetric spaces and the intrinsic characteristics of their restricted root lattices. Several important results can be obtained from this identification. In particular the Cartan classification of triplets of symmetric spaces with positive, zero and negative curvature gives rise to a new classification of random matrix ensembles. The review is organized into two main parts. In Part I the theory of symmetric spaces is reviewed with particular emphasis on the ideas relevant for appreciating the correspondence with random matrix theories. In Part II we discuss various applications of symmetric spaces to random matrix theories and in particular the new classification of disordered systems derived from the classification of symmetric spaces. We also review how the mapping from integrable Calogero-Sutherland models to symmetric spaces can be used in the theory of random matrices, with particular consequences for quantum transport problems. We conclude indicating some interesting new directions of research based on these identifications.
Spark plasma sintering of aluminum matrix composites
Yadav, Vineet
2011-12-01
Aluminum matrix composites make a distinct category of advanced engineering materials having superior properties over conventional aluminum alloys. Aluminum matrix composites exhibit high hardness, yield strength, and excellent wear and corrosion resistance. Due to these attractive properties, aluminum matrix composites materials have many structural applications in the automotive and the aerospace industries. In this thesis, efforts are made to process high strength aluminum matrix composites which can be useful in the applications of light weight and strong materials. Spark Plasma Sintering (SPS) is a relatively novel process where powder mixture is consolidated under the simultaneous influence of uniaxial pressure and pulsed direct current. In this work, SPS was used to process aluminum matrix composites having three different reinforcements: multi-wall carbon nanotubes (MWCNTs), silicon carbide (SiC), and iron-based metallic glass (MG). In Al-CNT composites, significant improvement in micro-hardness, nano-hardness, and compressive yield strength was observed. The Al-CNT composites further exhibited improved wear resistance and lower friction coefficient due to strengthening and self-lubricating effects of CNTs. In Al-SiC and Al-MG composites, microstructure, densification, and tribological behaviors were also studied. Reinforcing MG and SiC also resulted in increase in micro-hardness and wear resistance.
Max–min distance nonnegative matrix factorization
Wang, Jim Jing-Yan
2014-10-26
Nonnegative Matrix Factorization (NMF) has been a popular representation method for pattern classification problems. It tries to decompose a nonnegative matrix of data samples as the product of a nonnegative basis matrix and a nonnegative coefficient matrix. The columns of the coefficient matrix can be used as new representations of these data samples. However, traditional NMF methods ignore class labels of the data samples. In this paper, we propose a novel supervised NMF algorithm to improve the discriminative ability of the new representation by using the class labels. Using the class labels, we separate all the data sample pairs into within-class pairs and between-class pairs. To improve the discriminative ability of the new NMF representations, we propose to minimize the maximum distance of the within-class pairs in the new NMF space, and meanwhile to maximize the minimum distance of the between-class pairs. With this criterion, we construct an objective function and optimize it with regard to basis and coefficient matrices, and slack variables alternatively, resulting in an iterative algorithm. The proposed algorithm is evaluated on three pattern classification problems and experiment results show that it outperforms the state-of-the-art supervised NMF methods.
Phase diagram of matrix compressed sensing
Schülke, Christophe; Schniter, Philip; Zdeborová, Lenka
2016-12-01
In the problem of matrix compressed sensing, we aim to recover a low-rank matrix from a few noisy linear measurements. In this contribution, we analyze the asymptotic performance of a Bayes-optimal inference procedure for a model where the matrix to be recovered is a product of random matrices. The results that we obtain using the replica method describe the state evolution of the Parametric Bilinear Generalized Approximate Message Passing (P-BiG-AMP) algorithm, recently introduced in J. T. Parker and P. Schniter [IEEE J. Select. Top. Signal Process. 10, 795 (2016), 10.1109/JSTSP.2016.2539123]. We show the existence of two different types of phase transition and their implications for the solvability of the problem, and we compare the results of our theoretical analysis to the numerical performance reached by P-BiG-AMP. Remarkably, the asymptotic replica equations for matrix compressed sensing are the same as those for a related but formally different problem of matrix factorization.
Redesigning Triangular Dense Matrix Computations on GPUs
Charara, Ali
2016-08-09
A new implementation of the triangular matrix-matrix multiplication (TRMM) and the triangular solve (TRSM) kernels are described on GPU hardware accelerators. Although part of the Level 3 BLAS family, these highly computationally intensive kernels fail to achieve the percentage of the theoretical peak performance on GPUs that one would expect when running kernels with similar surface-to-volume ratio on hardware accelerators, i.e., the standard matrix-matrix multiplication (GEMM). The authors propose adopting a recursive formulation, which enriches the TRMM and TRSM inner structures with GEMM calls and, therefore, reduces memory traffic while increasing the level of concurrency. The new implementation enables efficient use of the GPU memory hierarchy and mitigates the latency overhead, to run at the speed of the higher cache levels. Performance comparisons show up to eightfold and twofold speedups for large dense matrix sizes, against the existing state-of-the-art TRMM and TRSM implementations from NVIDIA cuBLAS, respectively, across various GPU generations. Once integrated into high-level Cholesky-based dense linear algebra algorithms, the performance impact on the overall applications demonstrates up to fourfold and twofold speedups, against the equivalent native implementations, linked with cuBLAS TRMM and TRSM kernels, respectively. The new TRMM/TRSM kernel implementations are part of the open-source KBLAS software library (http://ecrc.kaust.edu.sa/Pages/Res-kblas.aspx) and are lined up for integration into the NVIDIA cuBLAS library in the upcoming v8.0 release.
Membrane-type matrix metalloproteinase-mediated angiogenesis in a fibrin-collagen matrix
Collen, A.; Hanemaaijer, R.; Lupu, F.; Quax, P.H.A.; Lent, N. van; Grimbergen, J.; Peters, E.; Koolwijk, P.; Hinsbergh, V.W.M. van
2003-01-01
Adult angiogenesis, associated with pathologic conditions, is often accompanied by the formation of a fibrinous exudate. This temporary matrix consists mainly of fibrin but is intermingled with plasma proteins and collagen fibers. The formation of capillary structures in a fibrinous matrix in vivo
The minimum amount of "matrix " needed for matrix-assisted pulsed laser deposition of biomolecules
DEFF Research Database (Denmark)
Tabetah, Marshall; Matei, Andreea; Constantinescu, Catalin
2014-01-01
of coarse-grained molecular dynamics simulations are performed for a model lysozyme-water system, where the water serves the role of volatile "matrix" that drives the ejection of the biomolecules. The simulations reveal a remarkable ability of a small (5-10 wt %) amount of matrix to cause the ejection...
Quaternion from rotation matrix. [four-parameter representation of coordinate transformation matrix
Shepperd, S. W.
1978-01-01
A quaternion is regarded as a four-parameter representation of a coordinate transformation matrix, where the four components of the quaternion are treated on an equal basis. This leads to a unified, compact, and singularity-free approach to determining the quaternion when the matrix is given.
Matrix transformation of Fibonacci band matrix on generalized $bv$-space and its dual spaces
Directory of Open Access Journals (Sweden)
Anupam Das
2018-07-01
Full Text Available In this paper we introduce a new sequence space $bv(\\hat{F}$ by using the Fibonacci band matrix $\\hat{F}.$ We also establish a few inclusion relations concerning this space and determine its $\\alpha-,\\beta-,\\gamma-$duals. Finally we characterize some matrix classes on the space $bv(\\hat{F}.$
A framework for general sparse matrix-matrix multiplication on GPUs and heterogeneous processors
DEFF Research Database (Denmark)
Liu, Weifeng; Vinter, Brian
2015-01-01
General sparse matrix-matrix multiplication (SpGEMM) is a fundamental building block for numerous applications such as algebraic multigrid method (AMG), breadth first search and shortest path problem. Compared to other sparse BLAS routines, an efficient parallel SpGEMM implementation has to handle...
An Efficient GPU General Sparse Matrix-Matrix Multiplication for Irregular Data
DEFF Research Database (Denmark)
Liu, Weifeng; Vinter, Brian
2014-01-01
General sparse matrix-matrix multiplication (SpGEMM) is a fundamental building block for numerous applications such as algebraic multigrid method, breadth first search and shortest path problem. Compared to other sparse BLAS routines, an efficient parallel SpGEMM algorithm has to handle extra...
Function of the sperm nuclear matrix.
Shaman, Jeffrey A; Yamauchi, Yasuhiro; Ward, W Steven
2007-01-01
Mammalian spermatozoa contain some of the most highly compact chromatin. This is due to the DNA binding proteins, the protamines, which replace most of the histones during spermiogenesis. This chromatin, however, shares some features with somatic cell chromatin. One of these is the organization of DNA into loop domains attached at their bases to a proteinaceous nuclear matrix. Several groups have shown that the sites at which DNA associates with the sperm nuclear matrix contain chromatin structures that are linked with specific functions. Recent data also suggest that the sperm nuclear matrix plays essential roles in the paternal pronucleus of the newly fertilized oocyte, suggesting that the sperm cell provides more information to the new embryo than solely the genetic material it delivers. Here, we will review these data which together give insight into the functional significance and requirements of sperm nuclear structure.
Matrix elements from moments of correlation functions
Energy Technology Data Exchange (ETDEWEB)
Chang, Chia Cheng [SLAC National Accelerator Lab., Menlo Park, CA (United States); Bouchard, Chris [College of William and Mary, Williamsburg, VA (United States); Orginos, Konstantinos [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States); Richards, David G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-10-01
Momentum-space derivatives of matrix elements can be related to their coordinate-space moments through the Fourier transform. We derive these expressions as a function of momentum transfer Q2 for asymptotic in/out states consisting of a single hadron. We calculate corrections to the finite volume moments by studying the spatial dependence of the lattice correlation functions. This method permits the computation of not only the values of matrix elements at momenta accessible on the lattice, but also the momentum-space derivatives, providing {\\it a priori} information about the Q2 dependence of form factors. As a specific application we use the method, at a single lattice spacing and with unphysically heavy quarks, to directly obtain the slope of the isovector form factor at various Q2, whence the isovector charge radius. The method has potential application in the calculation of any hadronic matrix element with momentum transfer, including those relevant to hadronic weak decays.
Nanomechanics of the Cartilage Extracellular Matrix
Han, Lin; Grodzinsky, Alan J.; Ortiz, Christine
2011-08-01
Cartilage is a hydrated biomacromolecular fiber composite located at the ends of long bones that enables proper joint lubrication, articulation, loading, and energy dissipation. Degradation of extracellular matrix molecular components and changes in their nanoscale structure greatly influence the macroscale behavior of the tissue and result in dysfunction with age, injury, and diseases such as osteoarthritis. Here, the application of the field of nanomechanics to cartilage is reviewed. Nanomechanics involves the measurement and prediction of nanoscale forces and displacements, intra- and intermolecular interactions, spatially varying mechanical properties, and other mechanical phenomena existing at small length scales. Experimental nanomechanics and theoretical nanomechanics have been applied to cartilage at varying levels of material complexity, e.g., nanoscale properties of intact tissue, the matrix associated with single cells, biomimetic molecular assemblies, and individual extracellular matrix biomolecules (such as aggrecan, collagen, and hyaluronan). These studies have contributed to establishing a fundamental mechanism-based understanding of native and engineered cartilage tissue function, quality, and pathology.
Interface matrix method in AFEN framework
Energy Technology Data Exchange (ETDEWEB)
Pogosbekyan, Leonid; Cho, Jin Young; Kim, Young Jin [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1997-12-31
In this study, we extend the application of the interface-matrix(IM) method for reflector modeling to Analytic Flux Expansion Nodal (AFEN) method. This include the modifications of the surface-averaged net current continuity and the net leakage balance conditions for IM method in accordance with AFEN formula. AFEN-interface matrix (AFEN-IM) method has been tested against ZION-1 benchmark problem. The numerical result of AFEN-IM method shows 1.24% of maximum error and 0.42% of root-mean square error in assembly power distribution, and 0.006% {Delta} k of neutron multiplication factor. This result proves that the interface-matrix method for reflector modeling can be useful in AFEN method. 3 refs., 4 figs. (Author)
Google matrix analysis of directed networks
Ermann, Leonardo; Frahm, Klaus M.; Shepelyansky, Dima L.
2015-10-01
In the past decade modern societies have developed enormous communication and social networks. Their classification and information retrieval processing has become a formidable task for the society. Because of the rapid growth of the World Wide Web, and social and communication networks, new mathematical methods have been invented to characterize the properties of these networks in a more detailed and precise way. Various search engines extensively use such methods. It is highly important to develop new tools to classify and rank a massive amount of network information in a way that is adapted to internal network structures and characteristics. This review describes the Google matrix analysis of directed complex networks demonstrating its efficiency using various examples including the World Wide Web, Wikipedia, software architectures, world trade, social and citation networks, brain neural networks, DNA sequences, and Ulam networks. The analytical and numerical matrix methods used in this analysis originate from the fields of Markov chains, quantum chaos, and random matrix theory.
A review of Indirect Matrix Converter Topologies
Directory of Open Access Journals (Sweden)
Salem Rahmani
2015-08-01
Full Text Available Abstract—Matrix Converter (MC is a modern direct AC/AC electrical power converter without dc-link capacitor. MC is operated in four quadrant, assuring a control of the output voltage, amplitude and frequency. The matrix converter has recently attracted significant attention among researchers and it has become increasing attractive for applications of wind energy conversion, military power supplies, induction motor drives, etc. Recently, different MC topologies have been proposed and developed which have their own advantages and disadvantages. Matrix converter can be classified as direct and indirect structures. The direct one has been elaborated in previous work. In this paper the indirect MCs are reviewed. Different characteristics of the indirect MC topologies are mentioned to show the strengths and weaknesses of such converter topologies.
Resolving resonances in R-matrix calculations
Energy Technology Data Exchange (ETDEWEB)
Ramirez, J.M.; Bautista, Manuel A. [Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas (IVIC), Caracas (Venezuela)
2002-10-28
We present a technique to obtain detailed resonance structures from R-matrix calculations of atomic cross sections for both collisional and radiative processes. The resolving resonances (RR) method relies on the QB method of Quigley-Berrington (Quigley L, Berrington K A and Pelan J 1998 Comput. Phys. Commun. 114 225) to find the position and width of resonances directly from the reactance matrix. Then one determines the symmetry parameters of these features and generates an energy mesh whereby fully resolved cross sections are calculated with minimum computational cost. The RR method is illustrated with the calculation of the photoionization cross sections and the unified recombination rate coefficients of Fe XXIV, O VI, and Fe XVII. The RR method reduces numerical errors arising from unresolved R-matrix cross sections in the computation of synthetic bound-free opacities, thermally averaged collision strengths and recombination rate coefficients. (author)
Interfaces between a fibre and its matrix
DEFF Research Database (Denmark)
Lilholt, Hans; Sørensen, Bent F.
2017-01-01
The interface between a fibre and its matrix represents an important element in the characterization and exploitation of composite materials. Both theoretical models and analyses of experimental data have been presented in the literature since modern composite were developed and many experiments......, the interfacial energy [J/m2], the interfacial frictional shear stress [MPa] and the mismatch strain [-] between fibre and matrix. The model has been used for the different modes of fibre pull-out and fibre fragmentation. In this paper it is demonstrated that the governing equations for the experimental...... parameters (applied load, debond length and relative fibre/matrix displacement) are rather similar for these test modes. A simplified analysis allows the direct determination of the three interface parameters from two plots for the experimental data. The complete analysis is demonstrated for steel fibres...
Effective Lagrangians and chiral random matrix theory
Energy Technology Data Exchange (ETDEWEB)
Halasz, M.A.; Verbaarschot, J.J.M. [Department of Physics, State University of New York, Stony Brook, New York 11794 (United States)
1995-08-15
Recently, sum rules were derived for the inverse eigenvalues of the Dirac operator. They were obtained in two different ways: (i) starting from the low-energy effective Lagrangian and (ii) starting from a random matrix theory with the symmetries of the Dirac operator. This suggests that the effective theory can be obtained directly from the random matrix theory. Previously, this was shown for three or more colors with fundamental fermions. In this paper we construct the effective theory from a random matrix theory for two colors in the fundamental representation and for an arbitrary number of colors in the adjoint representation. We construct a fermionic partition function for Majorana fermions in Euclidean spacetime. Their reality condition is formulated in terms of complex conjugation of the second kind.
Random matrix theory with an external source
Brézin, Edouard
2016-01-01
This is a first book to show that the theory of the Gaussian random matrix is essential to understand the universal correlations with random fluctuations and to demonstrate that it is useful to evaluate topological universal quantities. We consider Gaussian random matrix models in the presence of a deterministic matrix source. In such models the correlation functions are known exactly for an arbitrary source and for any size of the matrices. The freedom given by the external source allows for various tunings to different classes of universality. The main interest is to use this freedom to compute various topological invariants for surfaces such as the intersection numbers for curves drawn on a surface of given genus with marked points, Euler characteristics, and the Gromov–Witten invariants. A remarkable duality for the average of characteristic polynomials is essential for obtaining such topological invariants. The analysis is extended to nonorientable surfaces and to surfaces with boundaries.
Statistical properties of random matrix product states
Garnerone, Silvano; de Oliveira, Thiago R.; Haas, Stephan; Zanardi, Paolo
2010-11-01
We study the set of random matrix product states (RMPS) introduced by Garnerone, de Oliveira, and Zanardi [S. Garnerone, T. R. de Oliveira, and P. Zanardi, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.81.032336 81, 032336 (2010)] as a tool to explore foundational aspects of quantum statistical mechanics. In the present work, we provide an accurate numerical and analytical investigation of the properties of RMPS. We calculate the average state of the ensemble in the nonhomogeneous case, and numerically check the validity of this result. We also suggest using RMPS as a tool to approximate properties of general quantum random states. The numerical simulations presented here support the accuracy and efficiency of this approximation. These results suggest that any generalized canonical state can be approximated with high probability by the reduced density matrix of a RMPS, if the average matrix product states coincide with the associated microcanonical ensemble.
Dentin Matrix Proteins in Bone Tissue Engineering.
Ravindran, Sriram; George, Anne
2015-01-01
Dentin and bone are mineralized tissue matrices comprised of collagen fibrils and reinforced with oriented crystalline hydroxyapatite. Although both tissues perform different functionalities, they are assembled and orchestrated by mesenchymal cells that synthesize both collagenous and noncollagenous proteins albeit in different proportions. The dentin matrix proteins (DMPs) have been studied in great detail in recent years due to its inherent calcium binding properties in the extracellular matrix resulting in tissue calcification. Recent studies have shown that these proteins can serve both as intracellular signaling proteins leading to induction of stem cell differentiation and also function as nucleating proteins in the extracellular matrix. These properties make the DMPs attractive candidates for bone and dentin tissue regeneration. This chapter will provide an overview of the DMPs, their functionality and their proven and possible applications with respect to bone tissue engineering.
Betatron coupling: Merging Hamiltonian and matrix approaches
Directory of Open Access Journals (Sweden)
R. Calaga
2005-03-01
Full Text Available Betatron coupling is usually analyzed using either matrix formalism or Hamiltonian perturbation theory. The latter is less exact but provides a better physical insight. In this paper direct relations are derived between the two formalisms. This makes it possible to interpret the matrix approach in terms of resonances, as well as use results of both formalisms indistinctly. An approach to measure the complete coupling matrix and its determinant from turn-by-turn data is presented. Simulations using methodical accelerator design MAD-X, an accelerator design and tracking program, were performed to validate the relations and understand the scope of their application to real accelerators such as the Relativistic Heavy Ion Collider.
Bioengineering Human Myocardium on Native Extracellular Matrix
Guyette, Jacques P.; Charest, Jonathan M; Mills, Robert W; Jank, Bernhard J.; Moser, Philipp T.; Gilpin, Sarah E.; Gershlak, Joshua R.; Okamoto, Tatsuya; Gonzalez, Gabriel; Milan, David J.; Gaudette, Glenn R.; Ott, Harald C.
2015-01-01
Rationale More than 25 million individuals suffer from heart failure worldwide, with nearly 4,000 patients currently awaiting heart transplantation in the United States. Donor organ shortage and allograft rejection remain major limitations with only about 2,500 hearts transplanted each year. As a theoretical alternative to allotransplantation, patient-derived bioartificial myocardium could provide functional support and ultimately impact the treatment of heart failure. Objective The objective of this study is to translate previous work to human scale and clinically relevant cells, for the bioengineering of functional myocardial tissue based on the combination of human cardiac matrix and human iPS-derived cardiac myocytes. Methods and Results To provide a clinically relevant tissue scaffold, we translated perfusion-decellularization to human scale and obtained biocompatible human acellular cardiac scaffolds with preserved extracellular matrix composition, architecture, and perfusable coronary vasculature. We then repopulated this native human cardiac matrix with cardiac myocytes derived from non-transgenic human induced pluripotent stem cells (iPSCs) and generated tissues of increasing three-dimensional complexity. We maintained such cardiac tissue constructs in culture for 120 days to demonstrate definitive sarcomeric structure, cell and matrix deformation, contractile force, and electrical conduction. To show that functional myocardial tissue of human scale can be built on this platform, we then partially recellularized human whole heart scaffolds with human iPSC-derived cardiac myocytes. Under biomimetic culture, the seeded constructs developed force-generating human myocardial tissue, showed electrical conductivity, left ventricular pressure development, and metabolic function. Conclusions Native cardiac extracellular matrix scaffolds maintain matrix components and structure to support the seeding and engraftment of human iPS-derived cardiac myocytes, and enable
A fixed point method to compute solvents of matrix polynomials
Marcos, Fernando; Pereira, Edgar
2009-01-01
Matrix polynomials play an important role in the theory of matrix differential equations. We develop a fixed point method to compute solutions of matrix polynomials equations, where the matricial elements of the matrix polynomial are considered separately as complex polynomials. Numerical examples illustrate the method presented.
The Role of Matrix Metalloproteinases in Renal Diseases
Funda SAĞLAM
2011-01-01
Matrix metalloproteinases (MMPs) are a family of zinc dependent proteinases and the main promoters of extracellular matrix degradation. Their role in renal diseases is now being understood better. Several progressive renal diseases are characterized with persistent cell proliferation and abnormal production of extracellular matrix by mesengial cells. Understanding mesengial cell proliferation and the factors regulating extracellular matrix metabolism is therefore becoming more important. MMPs...
Role of work hardening characteristics of matrix alloys in the ...
Indian Academy of Sciences (India)
The strengthening of particulate reinforced metal–matrix composites is associated with a high dislocation density in the matrix due to the difference in coefficient of thermal expansion between the reinforcement and the matrix. While this is valid, the role of work hardening characteristics of the matrix alloys in strengthening of ...
48 CFR 1652.370 - Use of the matrix.
2010-10-01
... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Use of the matrix. 1652.370... HEALTH BENEFITS ACQUISITION REGULATION CLAUSES AND FORMS CONTRACT CLAUSES FEHBP Clause Matrix 1652.370 Use of the matrix. (a) The matrix in this section lists the FAR and FEHBAR clauses to be used with...
Formulation and Evaluation of Tramadol HCl Matrix Tablets Using ...
African Journals Online (AJOL)
Purpose: To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using. Carbopol ... Different natural and synthetic polymers are used for CR matrix systems which have the property to extend the release of drug from matrix system [2]. In matrix systems, the ..... Behera S. Investigation of Drug Polymer.
A diode matrix is an extremely low-density form of read-only memory. It's one of the earliest forms of ROMs (dating back to the 1950s). Each bit in the ROM is represented by the presence or absence of one diode. The ROM is easily user-writable using a soldering iron and pair of wire cutters.This diode matrix board is a floppy disk boot ROM for a PDP-11, and consists of 32 16-bit words. When you access an address on the ROM, the circuit returns the represented data from that address.
A diode matrix is an extremely low-density form of read-only memory. It's one of the earliest forms of ROMs (dating back to the 1950s). Each bit in the ROM is represented by the presence or absence of one diode. The ROM is easily user-writable using a soldering iron and pair of wire cutters.This diode matrix board is a floppy disk boot ROM for a PDP-11, and consists of 32 16-bit words. When you access an address on the ROM, the circuit returns the represented data from that address.
New components of the Golgi matrix
Xiang, Yi; Wang, Yanzhuang
2012-01-01
The eukaryotic Golgi apparatus is characterized by a stack of flattened cisternae that are surrounded by transport vesicles. The organization and function of the Golgi require Golgi matrix proteins, including GRASPs and golgins, which exist primarily as fiber-like bridges between Golgi cisternae or between cisternae and vesicles. In this review, we highlight recent findings on Golgi matrix proteins, including their roles in maintaining the Golgi structure, vesicle tethering, and novel, unexpected functions. These new discoveries further our understanding of the molecular mechanisms that maintain the structure and the function of the Golgi, as well as its relationship with other cellular organelles such as the centrosome. PMID:21494806
Unitarity Tests of the Neutrino Mixing Matrix
Qian, X; Diwan, M; Vogel, P
2013-01-01
We discuss unitarity tests of the neutrino mixing (PMNS) matrix. We show that the combination of solar neutrino experiments, medium-baseline and short-baseline reactor antineutrino experiments make it possible to perform the first direct unitarity test of the PMNS matrix. In particular, the measurements of Daya Bay and JUNO (a next generation medium-baseline reactor experiment) will lay the foundation of a precise unitarity test of $|U_{e1}|^2 + |U_{e2}|^2 + |U_{e3}|^2 = 1 $. Furthermore, the precision measurement of $\\sin^22\\theta_{13}$ in both the $\\bar{\
Conducted Emission Evaluation for Direct Matrix Converters
Nothofer, A.; Tarisciotti, L.; Greedy, S.; Empringham, L.; De Lillo, L.; Degano, M.
2016-05-01
Matrix converters have been recently proposed as an alternative solution to the standard back-to-back converter in aerospace applications. However, Electromagnetic Interference (EMI), in particular, conducted emissions represent a critical aspect for this converter family. Direct Matrix Converter (DMC) are usually modelled only at the normal operating frequency, but for the research presented in this paper, the model is modified in order to include a detailed high frequency description, which is of interest for conducted emission studies.This paper analyzes the performance of DMC, when different control and modulation techniques are used. Experimental results are shown to validate the simulation models.
Algorithms for quadratic matrix and vector equations
Poloni, Federico
2011-01-01
This book is devoted to studying algorithms for the solution of a class of quadratic matrix and vector equations. These equations appear, in different forms, in several practical applications, especially in applied probability and control theory. The equations are first presented using a novel unifying approach; then, specific numerical methods are presented for the cases most relevant for applications, and new algorithms and theoretical results developed by the author are presented. The book focuses on “matrix multiplication-rich” iterations such as cyclic reduction and the structured doubling algorithm (SDA) and contains a variety of new research results which, as of today, are only available in articles or preprints.
Computing multiple integrals involving matrix exponentials
Carbonell, F.; Jimenez, J. C.; Pedroso, L. M.
2008-03-01
In this paper, a generalization of a formula proposed by Van Loan [Computing integrals involving the matrix exponential, IEEE Trans. Automat. Control 23 (1978) 395-404] for the computation of multiple integrals of exponential matrices is introduced. In this way, the numerical evaluation of such integrals is reduced to the use of a conventional algorithm to compute matrix exponentials. The formula is applied for evaluating some kinds of integrals that frequently emerge in a number classical mathematical subjects in the framework of differential equations, numerical methods and control engineering applications.
Matrix representation of a Neural Network
DEFF Research Database (Denmark)
Christensen, Bjørn Klint
Processing, by David Rummelhart (Rummelhart 1986) for an easy-to-read introduction. What the paper does explain is how a matrix representation of a neural net allows for a very simple implementation. The matrix representation is introduced in (Rummelhart 1986, chapter 9), but only for a two-layer linear...... network and the feedforward algorithm. This paper develops the idea further to three-layer non-linear networks and the backpropagation algorithm. Figure 1 shows the layout of a three-layer network. There are I input nodes, J hidden nodes and K output nodes all indexed from 0. Bias-node for the hidden...
Diffusion method in random matrix theory
Grela, Jacek
2016-01-01
We introduce a calculational tool useful in computing ratios and products of characteristic polynomials averaged over Gaussian measures with an external source. The method is based on Dyson’s Brownian motion and Grassmann/complex integration formulas for determinants. The resulting formulas are exact for finite matrix size N and form integral representations convenient for large N asymptotics. Quantities obtained by the method are interpreted as averages over standard matrix models. We provide several explicit and novel calculations with special emphasis on the β =2 Girko-Ginibre ensembles.
Quark Spectra, Topology, and Random Matrix Theory
Energy Technology Data Exchange (ETDEWEB)
Edwards, R.G.; Heller, U.M. [SCRI, Florida State University, Tallahassee, Florida 32306-4130 (United States); Kiskis, J. [Department of Physics, University of California, Davis, California 95616 (United States); Narayanan, R. [Department of Physics, Building 510A, Brookhaven National Laboratory, P.O. Box 5000, Upton, New York 11973 (United States)
1999-05-01
Quark spectra in QCD are linked to fundamental properties of the theory including the identification of pions as the Goldstone bosons of spontaneously broken chiral symmetry. The lattice overlap Dirac operator provides a nonperturbative, ultraviolet-regularized description of quarks with the correct chiral symmetry. Properties of the spectrum of this operator and their relation to random matrix theory are studied here. In particular, the predictions from chiral random matrix theory in topologically nontrivial gauge field sectors are tested for the first time. {copyright} {ital 1999} {ital The American Physical Society}
Stochastic R matrix for Uq (An(1))
Kuniba, A.; Mangazeev, V. V.; Maruyama, S.; Okado, M.
2016-12-01
We show that the quantum R matrix for symmetric tensor representations of Uq (An(1)) satisfies the sum rule required for its stochastic interpretation under a suitable gauge. Its matrix elements at a special point of the spectral parameter are found to factorize into the form that naturally extends Povolotsky's local transition rate in the q-Hahn process for n = 1. Based on these results we formulate new discrete and continuous time integrable Markov processes on a one-dimensional chain in terms of n species of particles obeying asymmetric stochastic dynamics. Bethe ansatz eigenvalues of the Markov matrices are also given.
Geometric Aspects of Iterated Matrix Multiplication
DEFF Research Database (Denmark)
Gesmundo, Fulvio
2016-01-01
This paper studies geometric properties of the Iterated Matrix Multiplication polynomial and the hypersurface that it defines. We focus on geometric aspects that may be relevant for complexity theory such as the symmetry group of the polynomial, the dual variety and the Jacobian loci of the hyper......This paper studies geometric properties of the Iterated Matrix Multiplication polynomial and the hypersurface that it defines. We focus on geometric aspects that may be relevant for complexity theory such as the symmetry group of the polynomial, the dual variety and the Jacobian loci...
Matrix Tricks for Linear Statistical Models
Puntanen, Simo; Styan, George PH
2011-01-01
In teaching linear statistical models to first-year graduate students or to final-year undergraduate students there is no way to proceed smoothly without matrices and related concepts of linear algebra; their use is really essential. Our experience is that making some particular matrix tricks very familiar to students can substantially increase their insight into linear statistical models (and also multivariate statistical analysis). In matrix algebra, there are handy, sometimes even very simple "tricks" which simplify and clarify the treatment of a problem - both for the student and
How to get the Matrix Organization to Work
DEFF Research Database (Denmark)
Burton, Richard M.; Obel, Børge; Håkonsson, Dorthe Døjbak
2015-01-01
a matrix to work, taking a multi-contingency perspective. We translate the matrix concept for designers and managers who are considering a matrix organization and argue that three factors are critical for its success: (1) Strong purpose: Only choose the matrix structure if there are strong reasons...... for doing so, (2) Alignment among contingencies: A matrix can only be successful if key contingencies are aligned with the matrix’s purpose, and (3) Management of junctions: The success of a matrix depends on how well activities at the junctions of the matrix are managed....
The transfer matrix in four-dimensional CDT
Ambjorn, Jan; Gizbert-Studnicki, Jakub; Görlich, Andrzej; Jurkiewicz, Jerzy
2012-01-01
The Causal Dynamical Triangulation model of quantum gravity (CDT) has a transfer matrix, relating spatial geometries at adjacent (discrete lattice) times. The transfer matrix uniquely determines the theory. We show that the measurements of the scale factor of the (CDT) universe are well described by an effective transfer matrix where the matrix elements are labeled only by the scale factor. Using computer simulations we determine the effective transfer matrix elements and show how they relate...
1990-09-01
item$S, TLCB%, TLCRZ, TLRB%, TLRRZ, TLRA%,_ TLCA %, BClZ, BRIl COMMON A%, B% COMMON SHARED ROWA%, COLB%, ACBR% ’CALL intro CLEAR , , 1000 ’Increase...MATRIX BOXES TLRA% = 10 ’Top Left Row A MATRIX TLCA % = 16 ’Top Left Column A MATRIX TLCB% = 30 ’Top Left Column B MATRIX TLRB% = 10 ’Top Left row B...MATRIX TLCR% = 45 ’Top Left Column R MATRIX TLRR% = 10 ’Top Left Row R MATRIX IF COLA% 1 THEN ’one column of A TLCA % TLCA % + 13 TLCB% =TLCB% + 7 TLCR
Reimus, Paul W.; Callahan, Timothy J.; Ware, S. Doug; Haga, Marc J.; Counce, Dale A.
2007-08-01
Diffusion cell experiments were conducted to measure nonsorbing solute matrix diffusion coefficients in forty-seven different volcanic rock matrix samples from eight different locations (with multiple depth intervals represented at several locations) at the Nevada Test Site. The solutes used in the experiments included bromide, iodide, pentafluorobenzoate (PFBA), and tritiated water ( 3HHO). The porosity and saturated permeability of most of the diffusion cell samples were measured to evaluate the correlation of these two variables with tracer matrix diffusion coefficients divided by the free-water diffusion coefficient ( Dm/ D*). To investigate the influence of fracture coating minerals on matrix diffusion, ten of the diffusion cells represented paired samples from the same depth interval in which one sample contained a fracture surface with mineral coatings and the other sample consisted of only pure matrix. The log of ( Dm/ D*) was found to be positively correlated with both the matrix porosity and the log of matrix permeability. A multiple linear regression analysis indicated that both parameters contributed significantly to the regression at the 95% confidence level. However, the log of the matrix diffusion coefficient was more highly-correlated with the log of matrix permeability than with matrix porosity, which suggests that matrix diffusion coefficients, like matrix permeabilities, have a greater dependence on the interconnectedness of matrix porosity than on the matrix porosity itself. The regression equation for the volcanic rocks was found to provide satisfactory predictions of log( Dm/ D*) for other types of rocks with similar ranges of matrix porosity and permeability as the volcanic rocks, but it did a poorer job predicting log( Dm/ D*) for rocks with lower porosities and/or permeabilities. The presence of mineral coatings on fracture walls did not appear to have a significant effect on matrix diffusion in the ten paired diffusion cell experiments.
Error Analysis of Band Matrix Method
Taniguchi, Takeo; Soga, Akira
1984-01-01
Numerical error in the solution of the band matrix method based on the elimination method in single precision is investigated theoretically and experimentally, and the behaviour of the truncation error and the roundoff error is clarified. Some important suggestions for the useful application of the band solver are proposed by using the results of above error analysis.
Silica gel matrix immobilized Chlorophyta hydrodictyon africanum ...
African Journals Online (AJOL)
Aghomotsegin
2015-08-05
Aug 5, 2015 ... Chlorophyta hydrodictyon africanum was immobilized on a silica gel matrix to improve its mechanical properties. The algae-silica gel adsorbent was used for batch sorption studies of a cationic dye, methylene blue (MB). Optimum adsorption was obtained with a dosage of 0.8 g bio sorbent. Results.
Differential analysis of matrix convex functions
DEFF Research Database (Denmark)
Hansen, Frank; Tomiyama, Jun
2007-01-01
We analyze matrix convex functions of a fixed order defined in a real interval by differential methods as opposed to the characterization in terms of divided differences given by Kraus [F. Kraus, Über konvekse Matrixfunktionen, Math. Z. 41 (1936) 18-42]. We obtain for each order conditions for ma...
Involution symmetries and the PMNS matrix
Indian Academy of Sciences (India)
2017-10-09
Oct 9, 2017 ... C S Lam has suggested that the PMNS matrix (or at least some of its elements) can be predicted by embedding the residual symmetry of the leptonic mass terms into a bigger symmetry. We analyse the possibility that the residual symmetries consist of involution generators only and explore how Lam's idea ...
5D Black Holes and Matrix Strings
Dijkgraaf, R; Verlinde, E.; Verlinde, H.
1997-01-01
We derive the world-volume theory, the (non)-extremal entropy and background geometry of black holes and black strings constructed out of the NS IIA fivebrane within the framework of matrix theory. The CFT description of strings propagating in the black hole geometry arises as an effective field theory.
Simulating Microfracture In Metal-Matrix Composites
Mital, Subodh K.; Chamis, Christos C.; Gotsis, Pascal K.
1994-01-01
Computational procedures developed for simulating microfracture in metal-matrix/fiber composite materials under mechanical and/or thermal loads at ambient and high temperatures. Procedures evaluate microfracture behavior of composites, establish hierarchies and sequences of fracture modes, and examine influences of compliant layers and partial debonding on properties of composites and on initiation of microfractures in them.
Comparison of transition-matrix sampling procedures
DEFF Research Database (Denmark)
Yevick, D.; Reimer, M.; Tromborg, Bjarne
2009-01-01
We compare the accuracy of the multicanonical procedure with that of transition-matrix models of static and dynamic communication system properties incorporating different acceptance rules. We find that for appropriate ranges of the underlying numerical parameters, algorithmically simple yet high...... accurate procedures can be employed in place of the standard multicanonical sampling algorithm....
Abadir, Karim M.
2012-01-01
This note derives an explicit formula for the numerical calculation of the square root of a matrix, when this function exists. An example is given as an illustration of the formula. The condition for the existence of the square root is also given.
Rate matrix estimation from site frequency data.
Burden, Conrad J; Tang, Yurong
2017-02-01
A procedure is described for estimating evolutionary rate matrices from observed site frequency data. The procedure assumes (1) that the data are obtained from a constant size population evolving according to a stationary Wright-Fisher or decoupled Moran model; (2) that the data consist of a multiple alignment of a moderate number of sequenced genomes drawn randomly from the population; and (3) that within the genome a large number of independent, neutral sites evolving with a common mutation rate matrix can be identified. No restrictions are imposed on the scaled rate matrix other than that the off-diagonal elements are positive, their sum is ≪1, and that the rows of the matrix sum to zero. In particular the rate matrix is not assumed to be reversible. The key to the method is an approximate stationary solution to the diffusion limit, forward Kolmogorov equation for neutral evolution in the limit of low mutation rates. Copyright © 2016 Elsevier Inc. All rights reserved.
Incremental Nonnegative Matrix Factorization for Face Recognition
Directory of Open Access Journals (Sweden)
Wen-Sheng Chen
2008-01-01
Full Text Available Nonnegative matrix factorization (NMF is a promising approach for local feature extraction in face recognition tasks. However, there are two major drawbacks in almost all existing NMF-based methods. One shortcoming is that the computational cost is expensive for large matrix decomposition. The other is that it must conduct repetitive learning, when the training samples or classes are updated. To overcome these two limitations, this paper proposes a novel incremental nonnegative matrix factorization (INMF for face representation and recognition. The proposed INMF approach is based on a novel constraint criterion and our previous block strategy. It thus has some good properties, such as low computational complexity, sparse coefficient matrix. Also, the coefficient column vectors between different classes are orthogonal. In particular, it can be applied to incremental learning. Two face databases, namely FERET and CMU PIE face databases, are selected for evaluation. Compared with PCA and some state-of-the-art NMF-based methods, our INMF approach gives the best performance.
Opportunity potential matrix for Atlantic Canadians
Greg Danchuk; Ed Thomson
1992-01-01
Opportunity for provision of Parks Service benefit to Atlantic Canadians was investigated by mapping travel behaviour into a matrix in terms of origin, season, purpose, distance, time, and destination. Findings identified potential for benefit in several activity areas, particularly within residents' own province.
Electromagnetic Compatibility of Matrix Converter System
Directory of Open Access Journals (Sweden)
S. Fligl
2006-12-01
Full Text Available The presented paper deals with matrix converters pulse width modulation strategies design with emphasis on the electromagnetic compatibility. Matrix converters provide an all-silicon solution to the problem of converting AC power from one frequency to another, offering almost all the features required of an ideal static frequency changer. They possess many advantages compared to the conventional voltage or current source inverters. A matrix converter does not require energy storage components as a bulky capacitor or an inductance in the DC-link, and enables the bi-directional power flow between the power supply and load. The most of the contemporary modulation strategies are able to provide practically sinusoidal waveforms of the input and output currents with negligible low order harmonics, and to control the input displacement factor. The perspective of matrix converters regarding EMC in comparison with other types of converters is brightly evident because it is no need to use any equipment for power factor correction and current and voltage harmonics reduction. Such converter with proper control is properly compatible both with the supply mains and with the supplied load. A special digital control system was developed for the realized experimental test bed which makes it possible to achieve greater throughput of the digital control system and its variability.
Effect of matrix metalloproteinase promoter polymorphisms on ...
Indian Academy of Sciences (India)
Matrix metalloproteinase (MMP) promoter polymorphisms are considered to play roles in the aetiology of endometriosis and adenomyosis, however, the evidence available are inconsistent. We aimed to systematically review the asscociationbetween MMP-1 -1607 1G/2G MMP-2 -735 C/T, MMP-3 -1171 5A/6A and MMP-9 ...
Preliminary research of recombinant matrix extracellular ...
African Journals Online (AJOL)
... and predentin, but not by dental pulp cells. Furthermore, we used von kossa staining and the results suggested that, MEPE could induce mineralization and we propose that this protein had a potential effect on dental rehabilitation. Key words: Matrix extracellular phosphoglycoprotein (MEPE), mineralization Von kossa.
Marriage as Matrix, Metaphor or Mysticism
DEFF Research Database (Denmark)
Pedersen, Else Marie Wiberg
2015-01-01
Taking Julia Kristeva's 'Tales of Love' with its more or less slight treatment of Bernard's and Luther's peceptions of love as its point of departure, this article shows that both the monk Bernard and the married theologian Luther use conjugal love as a matrix for an abundant, heterogenous love b...
Better Size Estimation for Sparse Matrix Products
DEFF Research Database (Denmark)
Amossen, Rasmus Resen; Campagna, Andrea; Pagh, Rasmus
2010-01-01
We consider the problem of doing fast and reliable estimation of the number of non-zero entries in a sparse Boolean matrix product. Let n denote the total number of non-zero entries in the input matrices. We show how to compute a 1 ± ε approximation (with small probability of error) in expected...
Young Children, Gender and the Heterosexual Matrix
Paechter, Carrie
2017-01-01
In this paper I consider the adult focus of current mainstream gender theory. I relate this to how the concept of the heterosexual matrix originates in a social contract which excludes children from civil society. I argue that this exclusion is problematic both for theoretical reasons and from the perspective of children themselves. I start by…
Random matrix model for disordered conductors
Indian Academy of Sciences (India)
1. Introduction. Matrix models are being successfully employed in a variety of domains of physics includ- ing studies on heavy nuclei [1], mesoscopic disordered conductors [2,3], two-dimensional quantum gravity [4], and chaotic quantum systems [5]. Universal conductance fluctuations in metals [6] and spectral fluctuations in ...
Random matrix model for disordered conductors
Indian Academy of Sciences (India)
Keywords. Disordered conductors; random matrix theory; Dyson's Coulomb gas model. ... An interesting random walk problem associated with the joint probability distribution of the ensuing ensemble is discussed and its connection with level dynamics is brought out. It is further proved that Dyson's Coulomb gas analogy ...
Matrix model formulation of four dimensional gravity
Energy Technology Data Exchange (ETDEWEB)
De Pietri, Roberto
2001-03-01
The attempt of extending to higher dimensions the matrix model formulation of two-dimensional quantum gravity leads to the consideration of higher rank tensor models. We discuss how these models relate to four dimensional quantum gravity and the precise conditions allowing to associate a four-dimensional simplicial manifold to Feynman diagrams of a rank-four tensor model.
"Matrix" sobitub iga filosoofiaga / Rando Tooming
Tooming, Rando
2003-01-01
Andy ja Larry Wachowski ulmefilmide triloogia "Matrix" fenomeni analüüsist ajakirja "Vikerkaar" 2003. aasta 9. numbris, kus sellele on pühendatud nelja filosoofi artiklid ( Slavoj Zhizhek, Jüri Eintalu, Bruno Mölder, Tanel Tammet)
Acellular Dermal Matrix in Postmastectomy Breast Reconstruction
A.M.S. Ibrahim (Ahmed)
2014-01-01
markdownabstract__Abstract__ Over the last decade the use of acellular dermal matrix (ADM) in reconstructive breast surgery has been transformative. Some authors have gone as far as to suggest that it is the single most important advancement in prosthetic breast reconstruction. ADMs are able
On affine non-negative matrix factorization
DEFF Research Database (Denmark)
Laurberg, Hans; Hansen, Lars Kai
2007-01-01
We generalize the non-negative matrix factorization (NMF) generative model to incorporate an explicit offset. Multiplicative estimation algorithms are provided for the resulting sparse affine NMF model. We show that the affine model has improved uniqueness properties and leads to more accurate id...
Silica gel matrix immobilized Chlorophyta hydrodictyon africanum ...
African Journals Online (AJOL)
Chlorophyta hydrodictyon africanum was immobilized on a silica gel matrix to improve its mechanical properties. The algae-silica gel adsorbent was used for batch sorption studies of a cationic dye, methylene blue (MB). Optimum adsorption was obtained with a dosage of 0.8 g bio sorbent. Results from sorption studies ...
Polymer matrix electroluminescent materials and devices
Marrocco, III, Matthew L.; Motamedi, Farshad J [Claremont, CA; Abdelrazzaq, Feras Bashir [Covina, CA; Abdelrazzaq, legal representative, Bashir Twfiq
2012-06-26
Photoluminescent and electroluminescent compositions are provided which comprise a matrix comprising aromatic repeat units covalently coordinated to a phosphorescent or luminescent metal ion or metal ion complexes. Methods for producing such compositions, and the electroluminescent devices formed therefrom, are also disclosed.
Matrix compliance and the regulation of cytokinesis
Directory of Open Access Journals (Sweden)
Savitha Sambandamoorthy
2015-07-01
Full Text Available Integrin-mediated cell adhesion to the ECM regulates many physiological processes in part by controlling cell proliferation. It is well established that many normal cells require integrin-mediated adhesion to enter S phase of the cell cycle. Recent evidence indicates that integrins also regulate cytokinesis. Mechanical properties of the ECM can dictate entry into S phase; however, it is not known whether they also can affect the successful completion of cell division. To address this issue, we modulated substrate compliance using fibronectin-coated acrylamide-based hydrogels. Soft and hard substrates were generated with approximate elastic moduli of 1600 and 34,000 Pascals (Pa respectively. Our results indicate that dermal fibroblasts successfully complete cytokinesis on hard substrates, whereas on soft substrates, a significant number fail and become binucleated. Cytokinesis failure occurs at a step following the formation of the intercellular bridge connecting presumptive daughter cells, suggesting a defect in abscission. Like dermal fibroblasts, mesenchymal stem cells require cell-matrix adhesion for successful cytokinesis. However, in contrast to dermal fibroblasts, they are able to complete cytokinesis on both hard and soft substrates. These results indicate that matrix stiffness regulates the successful completion of cytokinesis, and does so in a cell-type specific manner. To our knowledge, our study is the first to demonstrate that matrix stiffness can affect cytokinesis. Understanding the cell-type specific contribution of matrix compliance to the regulation of cytokinesis will provide new insights important for development, as well as tissue homeostasis and regeneration.
The algebras of large N matrix mechanics
Energy Technology Data Exchange (ETDEWEB)
Halpern, M.B.; Schwartz, C.
1999-09-16
Extending early work, we formulate the large N matrix mechanics of general bosonic, fermionic and supersymmetric matrix models, including Matrix theory: The Hamiltonian framework of large N matrix mechanics provides a natural setting in which to study the algebras of the large N limit, including (reduced) Lie algebras, (reduced) supersymmetry algebras and free algebras. We find in particular a broad array of new free algebras which we call symmetric Cuntz algebras, interacting symmetric Cuntz algebras, symmetric Bose/Fermi/Cuntz algebras and symmetric Cuntz superalgebras, and we discuss the role of these algebras in solving the large N theory. Most important, the interacting Cuntz algebras are associated to a set of new (hidden!) local quantities which are generically conserved only at large N. A number of other new large N phenomena are also observed, including the intrinsic nonlocality of the (reduced) trace class operators of the theory and a closely related large N field identification phenomenon which is associated to another set (this time nonlocal) of new conserved quantities at large N.
Hierarchical matrix approximation of large covariance matrices
Litvinenko, Alexander
2015-11-30
We approximate large non-structured Matérn covariance matrices of size n×n in the H-matrix format with a log-linear computational cost and storage O(kn log n), where rank k ≪ n is a small integer. Applications are: spatial statistics, machine learning and image analysis, kriging and optimal design.
Resin diffusion through demineralized dentin matrix
Directory of Open Access Journals (Sweden)
CARVALHO Ricardo M.
1999-01-01
Full Text Available This paper has focused on the factors that may affect the permeability of adhesive resins into the demineralized dentin matrix during the development of the bonding process. The effects of surface moisture are discussed respectively to the adhesive systems, and the problems related to incomplete hybrid layer formation presented.
Matrix control of stem cell fate.
Even-Ram, Sharona; Artym, Vira; Yamada, Kenneth M
2006-08-25
A key challenge in stem cell research is to learn how to direct the differentiation of stem cells toward specific fates. In this issue of Cell, Engler et al. (2006) identify a new factor regulating stem cell fate: the elasticity of the matrix microenvironment. By changing the stiffness of the substrate, human mesenchymal stem cells could be directed along neuronal, muscle, or bone lineages.
Silver Matrix Composites - Structure and Properties
Directory of Open Access Journals (Sweden)
Wieczorek J.
2016-03-01
Full Text Available Phase compositions of composite materials determine their performance as well as physical and mechanical properties. Depending on the type of applied matrix and the kind, amount and morphology of the matrix reinforcement, it is possible to shape the material properties so that they meet specific operational requirements. In the paper, results of investigations on silver alloy matrix composites reinforced with ceramic particles are presented. The investigations enabled evaluation of hardness, tribological and mechanical properties as well as the structure of produced materials. The matrix of composite material was an alloy of silver and aluminium, magnesium and silicon. As the reinforcing phase, 20-60 μm ceramic particles (SiC, SiO2, Al2O3 and Cs were applied. The volume fraction of the reinforcing phase in the composites was 10%. The composites were produced using the liquid phase (casting technology, followed by plastic work (the KOBO method. The mechanical and tribological properties were analysed for plastic work-subjected composites. The mechanical properties were assessed based on a static tensile and hardness tests. The tribological properties were investigated under dry sliding conditions. The analysis of results led to determination of effects of the composite production technology on their performance. Moreover, a relationship between the type of reinforcing phase and the mechanical and tribological properties was established.
Limit properties of monotone matrix functions
Behrndt, Jussi; Hassi, Seppo; de Snoo, Henk; Wietsma, Rudi
2012-01-01
The basic objects in this paper are monotonically nondecreasing n x n matrix functions D(center dot) defined on some open interval l = (a, b) of R and their limit values D(a) and D(b) at the endpoints a and b which are, in general, selfadjoint relations in C-n. Certain space decompositions induced
Role of metastructural matrixes in optimization ecotourism
Directory of Open Access Journals (Sweden)
A. N. Leuchin
2010-01-01
Full Text Available In the article possibilities anthropocentric and ecocentric developing paradigms ecotourism are shown. The updating role institutional functions ecotourism an expert by metastructural matrixes of optimization tourist-institutional space (TIS is specified. Long-range directions of socially-ecological interaction in system of ecotourism are designated, measures on optimisation of this interaction are considered.
Fast output-sensitive matrix multiplication
DEFF Research Database (Denmark)
Jacob, Riko; Stöckel, Morten
2015-01-01
We consider the problem of multiplying two $U \\times U$ matrices $A$ and $C$ of elements from a field $\\F$. We present a new randomized algorithm that can use the known fast square matrix multiplication algorithms to perform fewer arithmetic operations than the current state of the art for output...
The Bushido Matrix for Couple Communication
Li, Chi-Sing; Lin, Yu-Fen; Ginsburg, Phil; Eckstein, Daniel
2012-01-01
The concept of Japanese Bushido and its seven virtues were introduced by the authors in this article for the practice and application of couple communication. The Bushido Matrix Worksheet (BMW) was created for enhancing couple's awareness and understanding of each other's values and experiences. An activity and a case study to demonstrate the use…
Extracellular matrix and tissue engineering applications
Fernandes, H.A.M.; Moroni, Lorenzo; van Blitterswijk, Clemens; de Boer, Jan
2009-01-01
The extracellular matrix is a key component during regeneration and maintenance of tissues and organs, and it therefore plays a critical role in successful tissue engineering as well. Tissue engineers should recognise that engineering technology can be deduced from natural repair processes. Due to
Proteases decode the extracellular matrix cryptome.
Ricard-Blum, Sylvie; Vallet, Sylvain D
2016-03-01
The extracellular matrix is comprised of 1100 core-matrisome and matrisome-associated proteins and of glycosaminoglycans. This structural scaffold contributes to the organization and mechanical properties of tissues and modulates cell behavior. The extracellular matrix is dynamic and undergoes constant remodeling, which leads to diseases if uncontrolled. Bioactive fragments, called matricryptins, are released from the extracellular proteins by limited proteolysis and have biological activities on their own. They regulate numerous physiological and pathological processes such as angiogenesis, cancer, diabetes, wound healing, fibrosis and infectious diseases and either improve or worsen the course of diseases depending on the matricryptins and on the molecular and biological contexts. Several protease families release matricryptins from core-matrisome and matrisome-associated proteins both in vitro and in vivo. The major proteases, which decrypt the extracellular matrix, are zinc metalloproteinases of the metzincin superfamily (matrixins, adamalysins and astacins), cysteine proteinases and serine proteases. Some matricryptins act as enzyme inhibitors, further connecting protease and matricryptin fates and providing intricate regulation of major physiopathological processes such as angiogenesis and tumorigenesis. They strengthen the role of the extracellular matrix as a key player in tissue failure and core-matrisome and matrisome-associated proteins as important therapeutic targets. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.
Algebraic Geometry Solves an Old Matrix Problem
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 12. Algebraic Geometry Solves an Old Matrix Problem. R Bhatia. Research News Volume 4 Issue 12 ... Author Affiliations. R Bhatia1. Statistics and Mathematics Unit, Indian Statistical Institute, 7, SJS Sansanwal Marg, New Delhi 110 016, India.
Matrix multiplication operators on Banach function spaces
Indian Academy of Sciences (India)
In this paper, we study the matrix multiplication operators on Banach function spaces and discuss their applications in semigroups for solving the abstract Cauchy problem. Author Affiliations. H Hudzik1 Rajeev Kumar2 Romesh Kumar2. Faculty of Mathematics and Computer Science, Adam Mickiewicz University ...
Erker, Christian G; Santamaria, Mario; Moellmann, Michael
2014-09-01
Weight in kilograms is a required parameter in the emergency medical care of children. In emergent situations, obtaining an accurate weight is often not possible. In such situations, weight can be estimated by using an age-dependent formula such as the EPLS-formula (age in years+4)×2. As recently recognized for emergency tapes, the habitus of the child has a major influence on weight estimation. In this study, the performance of various age-dependent formulas is to be investigated, with special regard to children demonstrating non-normal growth. The performance of various formulas for weight estimation in children growing along the 5th, 50th, and 95th percentile is investigated based on a mathematical model compared to the WHO and CDC reference percentiles using ICC and Bland-Altman methods. Additionally, a new formula for children demonstrating non-normal growth is derived by regression analysis and tested: f×age in years+6 with the factor f being 2 for "tall n' thin", 3 for normal and 4 for "tiny n' thick" children. All previously published formulas lack precision when applied to children outside the 50th percentile. The new habitus-adapted formula shows a better performance for children growing along the 5th or 95th percentile. The new formula provides enhanced precision in weight estimation and can help in reducing, e.g. drug dosing errors. It should be used for weight estimation in children demonstrating non-normal weight development and in situations when superior methods such as weighing or habitus-adapted emergency tapes are not applicable. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Using Excel to reduce a Square Matrix
Directory of Open Access Journals (Sweden)
Josef Holoubek
2012-01-01
Full Text Available When solving operations research problems, one can use either specialised computer programs such as Lingo, Lindo, Storm or more universal programs such Excel, Matlab, and R. To obtain the input data, one can use either a program’s own editor or other programs commonly available such as Excel. While the problem-solving methods, being part of various programs, are the subjects of numerous publications (such as Gros, 2003; Jablonský, 2002; Plevný – Žižka, 2007; Stevenson – Ozgur, 2009, the way the input data are obtained, recorded, and processed receives far less attention although this part of problem-solving requires considerable effort and, if the method for data recording is inadequate, may cause subsequent difficulties in their further processing. A problem known as “the travelling salesman problem” (TSP may serve as an example. Here, the input data form a “square matrix of distances”. This paper is concerned with some Excel tools that can be used to obtain and subsequently modify such a square matrix. Given a square m × m matrix, an ordinary user might want to reduce it to an i × i square matrix (where i < m without having to copy data from the matrix, skip some of its rows and/or columns or write a program to implement such a reduction.In her degree project, Kourková, 2009 was looking for an efficient method of reducing an Excel matrix. She had found no relevant papers on this subject concluding that the authors of the commercial program had not considered this. Therefore, she offered her own solution unconventionally using the contingency table menu option. Although this had resulted in the desired submatrix, some of its parts were superfluous and even baffling for the user.For this reason, the authors analyse the method of representing an m × m matrix and the way of its reduction. Finally, a better option is offered to achieve the desired objective as well as other methods of obtaining the required submatrix that even
A Tiny College Nurtures Big Ideas
Carlson, Scott
2012-01-01
The College of the Atlantic (COA)--330 students and 43 faculty members ensconced on Maine's remote Mount Desert Island--has resisted growth, seeing smallness as key to providing an unusual education that cuts across disciplines, rejects academic conventions, and takes a highly personalized approach to teaching and learning. The emphasis on…
Chemistry in motion: tiny synthetic motors.
Colberg, Peter H; Reigh, Shang Yik; Robertson, Bryan; Kapral, Raymond
2014-12-16
CONSPECTUS: Diffusion is the principal transport mechanism that controls the motion of solute molecules and other species in solution; however, the random walk process that underlies diffusion is slow and often nonspecific. Although diffusion is an essential mechanism for transport in the biological realm, biological systems have devised more efficient transport mechanisms using molecular motors. Most biological motors utilize some form of chemical energy derived from their surroundings to induce conformational changes in order to carry out specific functions. These small molecular motors operate in the presence of strong thermal fluctuations and in the regime of low Reynolds numbers, where viscous forces dominate inertial forces. Thus, their dynamical behavior is fundamentally different from that of macroscopic motors, and different mechanisms are responsible for the production of useful mechanical motion. There is no reason why our interest should be confined to the small motors that occur naturally in biological systems. Recently, micron and nanoscale motors that use chemical energy to produce directed motion by a number of different mechanisms have been made in the laboratory. These small synthetic motors also experience strong thermal fluctuations and operate in regimes where viscous forces dominate. Potentially, these motors could be directed to perform different transport tasks, analogous to those of biological motors, for both in vivo and in vitro applications. Although some synthetic motors execute conformational changes to effect motion, the majority do not, and, instead, they use other mechanisms to convert chemical energy into directed motion. In this Account, we describe how synthetic motors that operate by self-diffusiophoresis make use of a self-generated concentration gradient to drive motor motion. A description of propulsion by self-diffusiophoresis is presented for Janus particle motors comprising catalytic and noncatalytic faces. The properties of the dynamics of chemically powered motors are illustrated by presenting the results of particle-based simulations of sphere-dimer motors constructed from linked catalytic and noncatalytic spheres. The geometries of both Janus and sphere-dimer motors with asymmetric catalytic activity support the formation of concentration gradients around the motors. Because directed motion can occur only when the system is not in equilibrium, the nature of the environment and the role it plays in motor dynamics are described. Rotational Brownian motion also acts to limit directed motion, and it has especially strong effects for very small motors. We address the following question: how small can motors be and still exhibit effects due to propulsion, even if only to enhance diffusion? Synthetic motors have the potential to transform the manner in which chemical dynamical processes are carried out for a wide range of applications.
Abha Eli Phoboo
2015-01-01
A PhD student working on the ATLAS experiment has created a replica of the Large Hadron Collider using Lego building blocks. Nathan Readioff, from the University of Liverpool (see here), submitted his design to Lego Ideas (see here) this week and is now awaiting the 10,000 votes needed for it to qualify for the Lego Review, which decides if projects become new Lego products. You can help this project, vote online now! A computer simulation of the miniature Lego LHC, complete with four detectors connected with blue dipole magnets. His Lego design is a stylised model of the LHC, showcasing the four main detectors ALICE, ATLAS, CMS and LHCb at the micro scale. Each detector is small enough to fit in the palm of your hand, yet the details of the internal systems are intricate, revealed by cutaway walls. Every major detector component is represented by a Lego piece. The models are not strictly to scale with one another, but the same size base is used for each one to maximise the detail that can...
SMALLEY, DAVE E.
A DISCUSSION OF FLOOR MAINTENANCE AND CARE INTERMS OF BROKEN, WARPED, AND OTHERWISE DAMAGED CONDITIONS WHICH OFTEN REQUIRE REPLACEMENTS GIVES SUGGESTIONS FOR VARIOUS TYPES OF FLOORING MATERIAL. WOOD FLOOR CONDITIONS MAY INCLUDE--(1) CUPPED BOARDS, (2) BUCKLING BOARDS, AND (3) BROKEN BOARDS. A DETAILED DISCUSSION IS GIVEN OF METHODS FOR REMOVING…
Tiny Tool Converts Light to Electricity
Kamata, Masahiro; Tamamura, Yuna
2010-01-01
In Japan, junior high school students learn about energy conversion between kinetic and potential energy. In addition, they learn about energy conversion among different kinds of energy, such as mechanical, electrical, thermal, light and chemical. As for the conversion between electrical and light energy, teachers usually use lamps or LEDs to…
Massive machine to crack tiny nut
Sample, Ian
2006-01-01
"At security posts dotted around swiss fields between the Jura Mountains and Lake Geneva, scientists are installing hi-tech retina scans above shafts descending 80 metres to the world's largest scientific instrument."
Tiny galaxies help unravel dark matter mystery
O'Hanlon, Larry
2007-01-01
"The 70-year effort to unravel the mysteries of dark matter just got a big boost from some very puny galaxies. In the pas few years, a score of dwarf galaxies have been discovered hanging about the fringes of the Milky way. Now new measurements of the few stars int hese dwarfs reveal them to be dark mater distilleries, with upwards of 1'000 times more dark than normal matter." (3 pages)
Tiny Nanoparticles - A Big Battlefield Impact?
2014-10-01
cloth, with a specific circuit pattern. The circuits form radio frequency iden- tification ( RFID ) tags and can be used in security applications to...Other biomedical projects include the possibility of using gold nanoparticles as a replacement for chemotherapy in cancer patients. While ECBC and
A Tiny Bilbao in the Province?
DEFF Research Database (Denmark)
Jespersen, Line Marie Bruun
2014-01-01
In the 2000s, along a booming economy, the ideas behind the experience economy and the creative cities inspired policy makers and city planners throughout the western world (Pine and Gilmore 1999, Florida 2004, Klingman 2007). This resulted in urban development and regeneration projects where...... the utilization of cultural institutions, creative industries and the demands of the creative class were drivers in the development of the major cities, i.e. the ”Bilbao Effect”. From the major cities these ideas spread to smaller cities, which raised questions about critical mass, etc. This ”second wave...... of the welfare state, which focus on accessibility, a democratic and inclusive approach expressed in the form of culture projects that will enhance the quality of life and liveability in the local community. The paper discusses how and if the two rationales can be executed in the same projects: economic growth...
Solution of the Lyapunov matrix equation for a system with a time-dependent stiffness matrix
DEFF Research Database (Denmark)
Pommer, Christian; Kliem, Wolfhard
2004-01-01
The stability of the linearized model of a rotor system with non-symmetric strain and axial loads is investigated. Since we are using a fixed reference system, the differential equations have the advantage to be free of Coriolis and centrifugal forces. A disadvantage is nevertheless the occurrence...... of time-dependent periodic terms in the stiffness matrix. However, by solving the Lyapunov matrix equation we can formulate several stability conditions for the rotor system. Hereby the positive definiteness of a certain averaged stiffness matrix plays a crucial role....
Liver Fibrosis and Altered Matrix Synthesis
Directory of Open Access Journals (Sweden)
Katrin Neubauer
2001-01-01
Full Text Available Liver fibrosis represents the uniform response of liver to toxic, infectious or metabolic agents. The process leading to liver fibrosis resembles the process of wound healing, including the three phases following tissue injury: inflammation, synthesis of collagenous and noncollagenous extracellular matrix components, and tissue remodelling (scar formation. While a single liver tissue injury can be followed by an almost complete restitution ad integrum, the persistence of the original damaging noxa results in tissue damage. During the establishment of liver fibrosis, the basement membrane components collagen type IV, entactin and laminin increase and form a basement membrane-like structure within the space of Disse. The number of endothelial fenestrae of the sinusoids decreases. These changes of the sinusoids are called 'capillarization' because the altered structure of the sinusoids resembles that of capillaries. At the cellular level, origin of liver fibrogenesis is initiated by the damage of hepatocytes, resulting in the recruitment of inflammatory cells and platelets, and activation of Kupffer cells, with subsequent release of cytokines and growth factors. The hepatic stellate cells seem to be the primary target cells for these inflammatory stimuli, because during fibrogenesis, they undergo an activation process to a myofibroblast-like cell, which represents the major matrix-producing cell. Based on this pathophysiological mechanism, therapeutic methods are developed to inhibit matrix synthesis or stimulate matrix degradation. A number of substances are currently being tested that either neutralize fibrogenic stimuli and prevent the activation of hepatic stellate cells, or directly modulate the matrix metabolism. However, until now, the elimination of the hepatotoxins has been the sole therapeutic concept available for the treatment of liver fibrogenesis in humans.
Regulation of Corneal Stroma Extracellular Matrix Assembly
Chen, Shoujun; Mienaltowski, Michael J.; Birk, David E.
2014-01-01
The transparent cornea is the major refractive element of the eye. A finely controlled assembly of the stromal extracellular matrix is critical to corneal function, as well as in establishing the appropriate mechanical stability required to maintain corneal shape and curvature. In the stroma, homogeneous, small diameter collagen fibrils, regularly packed with a highly ordered hierarchical organization, are essential for function. This review focuses on corneal stroma assembly and the regulation of collagen fibrillogenesis. Corneal collagen fibrillogenesis involves multiple molecules interacting in sequential steps, as well as interactions between keratocytes and stroma matrix components. The stroma has the highest collagen V:I ratio in the body. Collagen V regulates the nucleation of protofibril assembly, thus controlling the number of fibrils and assembly of smaller diameter fibrils in the stroma. The corneal stroma is also enriched in small leucine-rich proteoglycans (SLRPs) that cooperate in a temporal and spatial manner to regulate linear and lateral collagen fibril growth. In addition, the fibril-associated collagens (FACITs) such as collagen XII and collagen XIV have roles in the regulation of fibril packing and inter-lamellar interactions. A communicating keratocyte network contributes to the overall and long-range regulation of stromal extracellular matrix assembly, by creating micro-domains where the sequential steps in stromal matrix assembly are controlled. Keratocytes control the synthesis of extracellular matrix components, which interact with the keratocytes dynamically to coordinate the regulatory steps into a cohesive process. Mutations or deficiencies in stromal regulatory molecules result in altered interactions and deficiencies in both transparency and refraction, leading to corneal stroma pathobiology such as stromal dystrophies, cornea plana and keratoconus. PMID:25819456
High-frequency matrix converter with square wave input
Carr, Joseph Alexander; Balda, Juan Carlos
2015-03-31
A device for producing an alternating current output voltage from a high-frequency, square-wave input voltage comprising, high-frequency, square-wave input a matrix converter and a control system. The matrix converter comprises a plurality of electrical switches. The high-frequency input and the matrix converter are electrically connected to each other. The control system is connected to each switch of the matrix converter. The control system is electrically connected to the input of the matrix converter. The control system is configured to operate each electrical switch of the matrix converter converting a high-frequency, square-wave input voltage across the first input port of the matrix converter and the second input port of the matrix converter to an alternating current output voltage at the output of the matrix converter.
2matrix: A Utility for Indel Coding and Phylogenetic Matrix Concatenation
Directory of Open Access Journals (Sweden)
Nelson R. Salinas
2014-01-01
Full Text Available Premise of the study: Phylogenetic analysis of DNA and amino acid sequences requires the creation of files formatted specifically for each analysis package. Programs currently available cannot simultaneously code inferred insertion/deletion (indel events in sequence alignments and concatenate data sets. Methods and Results: A novel Perl script, 2matrix, was created to concatenate matrices of non-molecular characters and/or aligned sequences and to code indels. 2matrix outputs a variety of formats compatible with popular phylogenetic programs. Conclusions: 2matrix efficiently codes indels and concatenates matrices of sequences and non-molecular data. It is available for free download under a GPL (General Public License open source license (https://github.com/nrsalinas/2matrix/archive/master.zip.
Directory of Open Access Journals (Sweden)
Catherine eChaussain
2013-11-01
Full Text Available Bacterial enzymes have long been considered solely accountable for the degradation of the dentin matrix during the carious process. However, the emerging literature suggests that host-derived enzymes, and in particular the matrix metalloproteinases (MMPs contained in dentin and saliva can play a major role in this process by their ability to degrade the dentin matrix from within. These findings are important since they open new therapeutic options for caries prevention and treatment. The possibility of using MMP inhibitors to interfere with dentin caries progression is discussed. Furthermore, the potential release of bioactive peptides by the enzymatic cleavage of dentin matrix proteins by MMPs during the carious process is discussed. These peptides, once identified, may constitute promising therapeutical tools for tooth and bone regeneration.
Optimizing Tpetra%3CU%2B2019%3Es sparse matrix-matrix multiplication routine.
Energy Technology Data Exchange (ETDEWEB)
Nusbaum, Kurtis Lee
2011-08-01
Over the course of the last year, a sparse matrix-matrix multiplication routine has been developed for the Tpetra package. This routine is based on the same algorithm that is used in EpetraExt with heavy modifications. Since it achieved a working state, several major optimizations have been made in an effort to speed up the routine. This report will discuss the optimizations made to the routine, its current state, and where future work needs to be done.
Solution of Second-Order IVP and BVP of Matrix Differential Models Using Matrix DTM
Directory of Open Access Journals (Sweden)
Reza Abazari
2012-01-01
Full Text Available We introduce a matrix form of differential transformation method (DTM and apply for nonlinear second-order initial value problems (IVPs and boundary value problems (BVPs of matrix models which are given by (=(,(,( and subject to initial conditions (=0,(=1 and boundary conditions (=0,(=1, where 0,1∈×. Also the convergence of present method is established. Several illustrative examples are given to demonstrate the effectiveness of the present method.
Modeling the formation of cell-matrix adhesions on a single 3D matrix fiber.
Escribano, J; Sánchez, M T; García-Aznar, J M
2015-11-07
Cell-matrix adhesions are crucial in different biological processes like tissue morphogenesis, cell motility, and extracellular matrix remodeling. These interactions that link cell cytoskeleton and matrix fibers are built through protein clutches, generally known as adhesion complexes. The adhesion formation process has been deeply studied in two-dimensional (2D) cases; however, the knowledge is limited for three-dimensional (3D) cases. In this work, we simulate different local extracellular matrix properties in order to unravel the fundamental mechanisms that regulate the formation of cell-matrix adhesions in 3D. We aim to study the mechanical interaction of these biological structures through a three dimensional discrete approach, reproducing the transmission pattern force between the cytoskeleton and a single extracellular matrix fiber. This numerical model provides a discrete analysis of the proteins involved including spatial distribution, interaction between them, and study of the different phenomena, such as protein clutches unbinding or protein unfolding. Copyright © 2015 Elsevier Ltd. All rights reserved.
Random matrix approach to categorical data analysis
Patil, Aashay; Santhanam, M. S.
2015-09-01
Correlation and similarity measures are widely used in all the areas of sciences and social sciences. Often the variables are not numbers but are instead qualitative descriptors called categorical data. We define and study similarity matrix, as a measure of similarity, for the case of categorical data. This is of interest due to a deluge of categorical data, such as movie ratings, top-10 rankings, and data from social media, in the public domain that require analysis. We show that the statistical properties of the spectra of similarity matrices, constructed from categorical data, follow random matrix predictions with the dominant eigenvalue being an exception. We demonstrate this approach by applying it to the data for Indian general elections and sea level pressures in the North Atlantic ocean.
Fiber study involving a polyimide matrix
Energy Technology Data Exchange (ETDEWEB)
Cano, R.J. [NASA Langley Research Center, Hampton, VA (United States); Rommel, M. [Northop Grumman Corp., Pico Rivera, CA (United States); Hinkley, J.A.; Estes, E.D. [NASA Langley Research Center, Hampton, VA (United States)
1996-12-31
Mechanical properties are presented for eight different intermediate modulus carbon fiber/ polyimide matrix composites. Two unsized carbon fibers (Thornel T650-42 and Hercules IM9) and two sized carbon fibers (high temperature sized Thornel T650-42 HTS and epoxy sized Toray T1000) were prepregged on the NASA LaRC Multipurpose Tape Machine using the NASA LaRC developed polyimide resin matrix, LaRC{trademark}-PETI-5, and the DuPont developed Avitnid{reg_sign} R1-16. Composite panels fabricated from these prepregs were evaluated to determine their mechanical properties. The data show the effects of using sized fibers on the processing and mechanical properties of polyimide composites.
Delocalization transition for the Google matrix.
Giraud, Olivier; Georgeot, Bertrand; Shepelyansky, Dima L
2009-08-01
We study the localization properties of eigenvectors of the Google matrix, generated both from the world wide web and from the Albert-Barabási model of networks. We establish the emergence of a delocalization phase for the PageRank vector when network parameters are changed. For networks with localized PageRank, eigenvalues of the matrix in the complex plane with a modulus above a certain threshold correspond to localized eigenfunctions while eigenvalues below this threshold are associated with delocalized relaxation modes. We argue that, for networks with delocalized PageRank, the efficiency of information retrieval by Google-type search is strongly affected since the PageRank values have no clear hierarchical structure in this case.
Geometric complexity theory and matrix powering
DEFF Research Database (Denmark)
Gesmundo, Fulvio; Ikenmeyer, Christian; Panova, Greta
2017-01-01
. Their approach works by multiplying the permanent polynomial with a high power of a linear form (a process called padding) and then comparing the orbit closures of the determinant and the padded permanent. This padding was recently used heavily to show no-go results for the method of shifted partial derivatives...... matrix power. This gives an equivalent but much cleaner homogeneous formulation of geometric complexity theory in which the padding is removed. This radically changes the representation theoretic questions involved to prove complexity lower bounds. We prove that in this homogeneous formulation...... there are no orbit occurrence obstructions that prove even superlinear lower bounds on the complexity of the permanent. This is the first no-go result in geometric complexity theory that rules out superlinear lower bounds in some model. Interestingly---in contrast to the determinant---the trace of a variable matrix...
Aluminum matrix composites reinforced with alumina nanoparticles
Casati, Riccardo
2016-01-01
This book describes the latest efforts to develop aluminum nanocomposites with enhanced damping and mechanical properties and good workability. The nanocomposites exhibited high strength, improved damping behavior and good ductility, making them suitable for use as wires. Since the production of metal matrix nanocomposites by conventional melting processes is considered extremely problematic (because of the poor wettability of the nanoparticles), different powder metallurgy routes were investigated, including high-energy ball milling and unconventional compaction methods. Special attention was paid to the structural characterization at the micro- and nanoscale, as uniform nanoparticle dispersion in metal matrix is of prime importance. The aluminum nanocomposites displayed an ultrafine microstructure reinforced with alumina nanoparticles produced in situ or added ex situ. The physical, mechanical and functional characteristics of the materials produced were evaluated using different mechanical tests and micros...
System Matrix Analysis for Computed Tomography Imaging.
Directory of Open Access Journals (Sweden)
Liubov Flores
Full Text Available In practical applications of computed tomography imaging (CT, it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data.
Matrix Factorizations, Minimal Models and Massey Products
Knapp, J; Knapp, Johanna; Omer, Harun
2006-01-01
We present a method to compute the full non-linear deformations of matrix factorizations for ADE minimal models. This method is based on the calculation of higher products in the cohomology, called Massey products. The algorithm yields a polynomial ring whose vanishing relations encode the obstructions of the deformations of the D-branes characterized by these matrix factorizations. This coincides with the critical locus of the effective superpotential which can be computed by integrating these relations. Our results for the effective superpotential are in agreement with those obtained from solving the A-infinity relations. We point out a relation to the superpotentials of Kazama-Suzuki models. We will illustrate our findings by various examples, putting emphasis on the E_6 minimal model.
Data from acellular human heart matrix.
Sánchez, Pedro L; Fernández-Santos, M Eugenia; Espinosa, M Angeles; González-Nicolas, M Angeles; Acebes, Judith R; Costanza, Salvatore; Moscoso, Isabel; Rodríguez, Hugo; García, Julio; Romero, Jesús; Kren, Stefan M; Bermejo, Javier; Yotti, Raquel; Del Villar, Candelas Pérez; Sanz-Ruiz, Ricardo; Elizaga, Jaime; Taylor, Doris A; Fernández-Avilés, Francisco
2016-09-01
Perfusion decellularization of cadaveric hearts removes cells and generates a cell-free extracellular matrix scaffold containing acellular vascular conduits, which are theoretically sufficient to perfuse and support tissue-engineered heart constructs. This article contains additional data of our experience decellularizing and testing structural integrity and composition of a large series of human hearts, "Acellular human heart matrix: a critical step toward whole heat grafts" (Sanchez et al., 2015) [1]. Here we provide the information about the heart decellularization technique, the valve competence evaluation of the decellularized scaffolds, the integrity evaluation of epicardial and myocardial coronary circulation, the pressure volume measurements, the primers used to assess cardiac muscle gene expression and, the characteristics of donors, donor hearts, scaffolds and perfusion decellularization process.
Data from acellular human heart matrix
Directory of Open Access Journals (Sweden)
Pedro L Sánchez
2016-09-01
Full Text Available Perfusion decellularization of cadaveric hearts removes cells and generates a cell-free extracellular matrix scaffold containing acellular vascular conduits, which are theoretically sufficient to perfuse and support tissue-engineered heart constructs. This article contains additional data of our experience decellularizing and testing structural integrity and composition of a large series of human hearts, “Acellular human heart matrix: a critical step toward whole heat grafts” (Sanchez et al., 2015 [1]. Here we provide the information about the heart decellularization technique, the valve competence evaluation of the decellularized scaffolds, the integrity evaluation of epicardial and myocardial coronary circulation, the pressure volume measurements, the primers used to assess cardiac muscle gene expression and, the characteristics of donors, donor hearts, scaffolds and perfusion decellularization process.
Embedded random matrix ensembles in quantum physics
Kota, V K B
2014-01-01
Although used with increasing frequency in many branches of physics, random matrix ensembles are not always sufficiently specific to account for important features of the physical system at hand. One refinement which retains the basic stochastic approach but allows for such features consists in the use of embedded ensembles. The present text is an exhaustive introduction to and survey of this important field. Starting with an easy-to-read introduction to general random matrix theory, the text then develops the necessary concepts from the beginning, accompanying the reader to the frontiers of present-day research. With some notable exceptions, to date these ensembles have primarily been applied in nuclear spectroscopy. A characteristic example is the use of a random two-body interaction in the framework of the nuclear shell model. Yet, topics in atomic physics, mesoscopic physics, quantum information science and statistical mechanics of isolated finite quantum systems can also be addressed using these ensemb...
Graphite matrix materials for nuclear waste isolation
Morgan, W. C.
1981-06-01
Manufacturing processes are reviewed herein, with primary emphasis on those processes which might be used to produce a graphic matrix for the waste forms. The approach involves the low temperature compaction of a finely ground powder produced from graphitized petroleum coke. The resultant compacts should have fairly good strength, low permeability to both liquids and gases, and anisotropic physical properties. In particular, the anisotropy of the thermal expansion coefficients and the thermal conductivity should be advantageous for this application. With two possible exceptions, the graphite matrix appears to be superior t the metal alloy matrices which have been recommended in prior studies. The two possible exceptions are the requirements on strength and permeability; both requirements will be strongly influenced by the containment design, including the choice of materials and the waste form, of the multibarrier package.
CMH-17 Volume 5 Ceramic Matrix Composites
Andrulonis, Rachael; Kiser, J. Douglas; David, Kaia E.; Davies, Curtis; Ashforth, Cindy
2017-01-01
A wide range of issues must be addressed during the process of certifying CMC (ceramic matrix composite) components for use in commercial aircraft. The Composite Materials Handbook-17, Volume 5, Revision A on ceramic matrix composites has just been revised to help support FAA certification of CMCs for elevated temperature applications. The handbook supports the development and use of CMCs through publishing and maintaining proven, reliable engineering information and standards that have been thoroughly reviewed. Volume 5 contains detailed sections describing CMC materials processing, design analysis guidelines, testing procedures, and data analysis and acceptance. A review of the content of this latest revision will be presented along with a description of how CMH-17, Volume 5 could be used by the FAA (Federal Aviation Administration) and others in the future.
Social patterns revealed through random matrix theory
Sarkar, Camellia; Jalan, Sarika
2014-11-01
Despite the tremendous advancements in the field of network theory, very few studies have taken weights in the interactions into consideration that emerge naturally in all real-world systems. Using random matrix analysis of a weighted social network, we demonstrate the profound impact of weights in interactions on emerging structural properties. The analysis reveals that randomness existing in particular time frame affects the decisions of individuals rendering them more freedom of choice in situations of financial security. While the structural organization of networks remains the same throughout all datasets, random matrix theory provides insight into the interaction pattern of individuals of the society in situations of crisis. It has also been contemplated that individual accountability in terms of weighted interactions remains as a key to success unless segregation of tasks comes into play.
Random matrix theory for underwater sound propagation
Hegewisch, K. C.; Tomsovic, S.
2012-02-01
Ocean acoustic propagation can be formulated as a wave guide with a weakly random medium generating multiple scattering. Twenty years ago, this was recognized as a quantum chaos problem, and yet random matrix theory, one pillar of quantum or wave chaos studies, has never been introduced into the subject. The modes of the wave guide provide a representation for the propagation, which in the parabolic approximation is unitary. Scattering induced by the ocean's internal waves leads to a power-law random banded unitary matrix ensemble for long-range deep-ocean acoustic propagation. The ensemble has similarities, but differs, from those introduced for studying the Anderson metal-insulator transition. The resulting long-range propagation ensemble statistics agree well with those of full wave propagation using the parabolic equation.
Quantum algorithm for support matrix machines
Duan, Bojia; Yuan, Jiabin; Liu, Ying; Li, Dan
2017-09-01
We propose a quantum algorithm for support matrix machines (SMMs) that efficiently addresses an image classification problem by introducing a least-squares reformulation. This algorithm consists of two core subroutines: a quantum matrix inversion (Harrow-Hassidim-Lloyd, HHL) algorithm and a quantum singular value thresholding (QSVT) algorithm. The two algorithms can be implemented on a universal quantum computer with complexity O[log(npq) ] and O[log(pq)], respectively, where n is the number of the training data and p q is the size of the feature space. By iterating the algorithms, we can find the parameters for the SMM classfication model. Our analysis shows that both HHL and QSVT algorithms achieve an exponential increase of speed over their classical counterparts.
Photoacoustic measurement of lutein in biological matrix
Bicanic, D.; Luterotti, S.; Becucci, M.; Fogliano, V.; Versloot, P.
2005-06-01
Photoacoustic (PA) spectroscopy was applied for the first time to quantify lutein in a complex biological matrix. Standard addition of lutein to a biological low-lutein matrix was used for the calibration. The PA signal was found linearly proportional (R > 0.98) to lutein concentration up to 0.3% (w/w). The dynamic range of concentrations extends to 1% (w/w) lutein. For a given experimental set-up the responsivity of PA detector within the range of linearity was estimated to 1.1 mV/1% lutein. Precision of repeated analyses is good with average RSD values of 4 and 5% for blanks and spiked samples, respectively. The analytical parameters indicate that the PA method is fast and sensitive enough for quantification of lutein in supplementary drugs and in the lutein-rich foods.
Fetal hypoxia and programming of matrix metalloproteinases.
Tong, Wenni; Zhang, Lubo
2012-02-01
Fetal hypoxia adversely affects the brain and heart development, yet the mechanisms responsible remain elusive. Recent studies indicate an important role of the extracellular matrix in fetal development and tissue remodeling. The matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMPs) have been implicated in a variety of physiological and pathological processes in the cardiovascular and central nervous systems. This review summarizes current knowledge of the mechanisms by which fetal hypoxia induces the imbalance of MMPs, TIMPs and collagen expression patterns, resulting in growth restriction and aberrant tissue remodeling in the developing heart and brain. Collectively, this information could lead to the development of preventive diagnoses and therapeutic strategies in the fetal programming of cardiovascular and neurological disorders. Copyright © 2011 Elsevier Ltd. All rights reserved.
The super period matrix with Ramond punctures
Witten, Edward
2015-06-01
We generalize the super period matrix of a super Riemann surface to the case that Ramond punctures are present. For a super Riemann surface of genus g with 2 r Ramond punctures, we define, modulo certain choices that generalize those in the classical theory (and assuming a certain generic condition is satisfied), a g | r × g | r period matrix that is symmetric in the Z2-graded sense. As an application, we analyze the genus 2 vacuum amplitude in string theory compactifications to four dimensions that are supersymmetric at tree level. We find an explanation for a result that has been found in orbifold examples in explicit computations by D'Hoker and Phong: with their integration procedure, the genus 2 vacuum amplitude always vanishes "pointwise" after summing over spin structures, and hence is given entirely by a boundary contribution.
The Lehmer Matrix and Its Recursive Analogue
2010-01-01
Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty...and p = 1 (the Fibonacci sequence case), we have 1 12 1 3 1 4 1 5 1 2 1 2 3 2 4 2 5 1 3 2 3 1 3 4 3 5 1 4 2 4 3 4 1 4 5 1 5 2 5 3 5 4 5 1...special cases of the matrix Fn, we take the matrix F0n ob- tained using the Fibonacci sequence, that is, Fn+1 = Fn+Fn−1, F0 = 0, F1 = 1. The determinant
Studying genetic code by a matrix approach.
Crowder, Tanner; Li, Chi-Kwong
2010-05-01
Following Petoukhov and his collaborators, we use two length n zero-one sequences, alpha and beta, to represent a length n genetic sequence (alpha/beta) so that the columns of (alpha/beta) have the following correspondence with the nucleotides: C ~ (0/0), U ~ (1/0), G ~ (1/1), A ~ (0/1). Using the Gray code ordering to arrange alpha and beta, we build a 2(n) x 2(n) matrix C(n) including all the 4(n) length n genetic sequences. Furthermore, we use the Hamming distance of alpha and beta to construct a 2(n) x 2(n) matrix D(n). We explore structures of these matrices, refine the results in earlier papers, and propose new directions for further research.
Matrix Metalloproteinases as Regulators of Periodontal Inflammation
Franco, Cavalla; Patricia, Hernández-Ríos; Timo, Sorsa; Claudia, Biguetti; Marcela, Hernández
2017-01-01
Periodontitis are infectious diseases characterized by immune-mediated destruction of periodontal supporting tissues and tooth loss. Matrix metalloproteinases (MMPs) are key proteases involved in destructive periodontal diseases. The study and interest in MMP has been fuelled by emerging evidence demonstrating the broad spectrum of molecules that can be cleaved by them and the myriad of biological processes that they can potentially regulate. The huge complexity of MMP functions within the ‘protease web’ is crucial for many physiologic and pathologic processes, including immunity, inflammation, bone resorption, and wound healing. Evidence points out that MMPs assemble in activation cascades and besides their classical extracellular matrix substrates, they cleave several signalling molecules—such as cytokines, chemokines, and growth factors, among others—regulating their biological functions and/or bioavailability during periodontal diseases. In this review, we provide an overview of emerging evidence of MMPs as regulators of periodontal inflammation. PMID:28218665
Nanophosphor composite scintillators comprising a polymer matrix
Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David
2010-11-16
An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.
Hierarchical matrix approximation of large covariance matrices
Litvinenko, Alexander
2015-01-05
We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(nlogn). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and op- timal design.
Hierarchical matrix approximation of large covariance matrices
Litvinenko, Alexander
2015-01-07
We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(n log n). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and optimal design
Graphite matrix materials for nuclear waste isolation
Energy Technology Data Exchange (ETDEWEB)
Morgan, W.C.
1981-06-01
At low temperatures, graphites are chemically inert to all but the strongest oxidizing agents. The raw materials from which artificial graphites are produced are plentiful and inexpensive. Morover, the physical properties of artificial graphites can be varied over a very wide range by the choice of raw materials and manufacturing processes. Manufacturing processes are reviewed herein, with primary emphasis on those processes which might be used to produce a graphite matrix for the waste forms. The approach, recommended herein, involves the low-temperature compaction of a finely ground powder produced from graphitized petroleum coke. The resultant compacts should have fairly good strength, low permeability to both liquids and gases, and anisotropic physical properties. In particular, the anisotropy of the thermal expansion coefficients and the thermal conductivity should be advantageous for this application. With two possible exceptions, the graphite matrix appears to be superior to the metal alloy matrices which have been recommended in prior studies. The two possible exceptions are the requirements on strength and permeability; both requirements will be strongly influenced by the containment design, including the choice of materials and the waste form, of the multibarrier package. Various methods for increasing the strength, and for decreasing the permeability of the matrix, are reviewed and discussed in the sections in Incorporation of Other Materials and Elimination of Porosity. However, it would be premature to recommend a particular process until the overall multi-barrier design is better defined. It is recommended that increased emphasis be placed on further development of the low-temperature compacted graphite matrix concept.
Ceramic Matrix Composites for Rotorcraft Engines
Halbig, Michael C.
2011-01-01
Ceramic matrix composite (CMC) components are being developed for turbine engine applications. Compared to metallic components, the CMC components offer benefits of higher temperature capability and less cooling requirements which correlates to improved efficiency and reduced emissions. This presentation discusses a technology develop effort for overcoming challenges in fabricating a CMC vane for the high pressure turbine. The areas of technology development include small component fabrication, ceramic joining and integration, material and component testing and characterization, and design and analysis of concept components.
Aluminium matrix composites fabricated by infiltration method
L.A. Dobrzański; M. Kremzer; A.J. Nowak; Nagel, A.
2009-01-01
Purpose: The aim of this work is to examine the structure and properties of metal matrix composites obtained by infiltration method of porous ceramic preforms by liquid aluminium alloy.Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of ceramic powder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the pore forming the carbon fibers Sigrafil C10 M250 UNS were used. Then ceramic preforms were infiltrated with liquid eutectic EN ...
New Polyurethanes with a polyurea matrix
Peshkov, Vladimir; Behrendt, Gerhard; Evtimova, Rozeta; Herzog, Michael
2012-01-01
Based on a previously published (Peshkov 2011) synthesis route of nanoscale oligourea dispersion polyols (NODP) a new type of polyurethanes with a polyurea matrix was developed. Polyurethanes with high hardness and elasticity were prepared by reacting a formulation based on the NODP’s and di- or polyisocyanates. The polyurethanes obtained as films were characterised by mechanical tests and dynamic mechanical analysis (DMA). The phase structure depends on the amount of nanoparticles present, t...
Spin Forming of Aluminum Metal Matrix Composites
Lee, Jonathan A.; Munafo, Paul M. (Technical Monitor)
2001-01-01
An exploratory effort between NASA-Marshall Space Flight Center (MSFC) and SpinCraft, Inc., to experimentally spin form cylinders and concentric parts from small and thin sheets of aluminum Metal Matrix Composites (MMC), successfully yielded good microstructure data and forming parameters. MSFC and SpinCraft will collaborate on the recent technical findings and develop strategy to implement this technology for NASA's advanced propulsion and airframe applications such as pressure bulkheads, combustion liner assemblies, propellant tank domes, and nose cone assemblies.
The Cartan matrix of a centralizer algebra
Indian Academy of Sciences (India)
cij = [Pi : Dj ]. The goal of this article is to compute the Cartan matrix of Л. We also describe its radical and principal indecomposable modules. 3. Preliminaries. Let A be a finite ... indecomposable Pi there exists a primitive idempotent ei such that 1 = ∑k i=1 ei and ei 's .... are isomorphic for a fixed value of i. Let Pi = Mλ(E)ei1 ...
Random Matrix Theory and Elliptic Curves
2014-11-24
lecture on random matrix models for elliptic curves at the combined meeting of the Australian and New Zealand mathematical societies Melbourne, Australia...organizer). Associated with the Chichely meeting will be a special volume of the Philosophical Transactions of the Royal Society (the world’s oldest...Distribution A: Approved for public release; distribution is unlimited. 5 USE OF SUPPORT 8 • JPK was awarded a Royal Society Wolfson Research Merit
Absorption properties of waste matrix materials
Energy Technology Data Exchange (ETDEWEB)
Briggs, J.B. [Idaho National Engineering Lab., Idaho Falls, ID (United States)
1997-06-01
This paper very briefly discusses the need for studies of the limiting critical concentration of radioactive waste matrix materials. Calculated limiting critical concentration values for some common waste materials are listed. However, for systems containing large quantities of waste materials, differences up to 10% in calculated k{sub eff} values are obtained by changing cross section data sets. Therefore, experimental results are needed to compare with calculation results for resolving these differences and establishing realistic biases.
Pseudo-Hermitian random matrix theory
Srivastava, S. C. L.; Jain, S. R.
2013-02-01
Complex extension of quantum mechanics and the discovery of pseudo-unitarily invariant random matrix theory has set the stage for a number of applications of these concepts in physics. We briefly review the basic ideas and present applications to problems in statistical mechanics where new results have become possible. We have found it important to mention the precise directions where advances could be made if further results become available.
Pseudo-Hermitian random matrix theory
Srivastava, Shashi C. L.; Jain, S. R.
2013-01-01
Complex extension of quantum mechanics and the discovery of pseudo-unitarily invariant random matrix theory has set the stage for a number of applications of these concepts in physics. We briefly review the basic ideas and present applications to problems in statistical mechanics where new results have become possible. We have found it important to mention the precise directions where advances could be made if further results become available.
A Matrix Formalism for Landau Damping
Energy Technology Data Exchange (ETDEWEB)
Prabhakar, Shyam
1998-10-20
Existing methods of analyzing the effect of bunch-to-bunch tune shifts on coupled bunch instabilities are applicable to beams with a single unstable mode, or a few non-interacting unstable modes. We present a more general approach that involves computing the eigenvalues of a reduced state matrix. The method is applied to the analysis of PEP-II longitudinal coupled bunch modes, a large number of which are unstable in the absence of feedback.
Enforced Sparse Non-Negative Matrix Factorization
2016-01-23
mixture of topics constitutes a document. Other common methods for topic modeling include the following: latent semantic analysis (LSA) [1...probabilistic latent semantic analysis (PLSA) [2], and term frequency- inverse document frequency (TF-IDF) [3] analysis. More recently, non-negative matrix...3, pp. 993–1022, 2003. [2] T. Hofmann, “Probabilistic latent semantic indexing,” in Proceedings of the 22nd Annual International ACM SIGIR
Reducing Actinide Production Using Inert Matrix Fuels
Energy Technology Data Exchange (ETDEWEB)
Deinert, Mark [Colorado School of Mines, Golden, CO (United States)
2017-08-23
The environmental and geopolitical problems that surround nuclear power stem largely from the longlived transuranic isotopes of Am, Cm, Np and Pu that are contained in spent nuclear fuel. New methods for transmuting these elements into more benign forms are needed. Current research efforts focus largely on the development of fast burner reactors, because it has been shown that they could dramatically reduce the accumulation of transuranics. However, despite five decades of effort, fast reactors have yet to achieve industrial viability. A critical limitation to this, and other such strategies, is that they require a type of spent fuel reprocessing that can efficiently separate all of the transuranics from the fission products with which they are mixed. Unfortunately, the technology for doing this on an industrial scale is still in development. In this project, we explore a strategy for transmutation that can be deployed using existing, current generation reactors and reprocessing systems. We show that use of an inert matrix fuel to recycle transuranics in a conventional pressurized water reactor could reduce overall production of these materials by an amount that is similar to what is achievable using proposed fast reactor cycles. Furthermore, we show that these transuranic reductions can be achieved even if the fission products are carried into the inert matrix fuel along with the transuranics, bypassing the critical separations hurdle described above. The implications of these findings are significant, because they imply that inert matrix fuel could be made directly from the material streams produced by the commercially available PUREX process. Zirconium dioxide would be an ideal choice of inert matrix in this context because it is known to form a stable solid solution with both fission products and transuranics.
ANL Critical Assembly Covariance Matrix Generation
Energy Technology Data Exchange (ETDEWEB)
McKnight, Richard D. [Argonne National Lab. (ANL), Argonne, IL (United States); Grimm, Karl N. [Argonne National Lab. (ANL), Argonne, IL (United States)
2014-01-15
This report discusses the generation of a covariance matrix for selected critical assemblies that were carried out by Argonne National Laboratory (ANL) using four critical facilities-all of which are now decommissioned. The four different ANL critical facilities are: ZPR-3 located at ANL-West (now Idaho National Laboratory- INL), ZPR-6 and ZPR-9 located at ANL-East (Illinois) and ZPPr located at ANL-West.
Corrosion Behavior of Metal Matrix Composites
1993-01-01
high tensile strength make Gif/Cu composites ideal candidates for high heat flux structures such as space power radiator panels where component...Feasibility Studies of Graphite Fiber Reinforced Copper Matrix Composites for Space Power Radiator Panels," NASA TM- 102328, Lewis Research Center...Strength Strengh in 2 in. Hardness Densiry Elasticity Conducuvir/ (KPSI) (KPSI) (%) (Rcckwell) b/•n3) (MPSI) (68cF.BTU /fLhi.°F) DSC GlidCop AL-60 75 bt
Google matrix, dynamical attractors, and Ulam networks.
Shepelyansky, D L; Zhirov, O V
2010-03-01
We study the properties of the Google matrix generated by a coarse-grained Perron-Frobenius operator of the Chirikov typical map with dissipation. The finite-size matrix approximant of this operator is constructed by the Ulam method. This method applied to the simple dynamical model generates directed Ulam networks with approximate scale-free scaling and characteristics being in certain features similar to those of the world wide web with approximate scale-free degree distributions as well as two characteristics similar to the web: a power-law decay in PageRank that mirrors the decay of PageRank on the world wide web and a sensitivity to the value alpha in PageRank. The simple dynamical attractors play here the role of popular websites with a strong concentration of PageRank. A variation in the Google parameter alpha or other parameters of the dynamical map can drive the PageRank of the Google matrix to a delocalized phase with a strange attractor where the Google search becomes inefficient.
Matrix Product States for Lattice Field Theories
Bañuls, Mari Carmen; Cirac, J Ignacio; Jansen, Karl; Saito, Hana
2013-01-01
The term Tensor Network States (TNS) refers to a number of families of states that represent different ans\\"atze for the efficient description of the state of a quantum many-body system. Matrix Product States (MPS) are one particular case of TNS, and have become the most precise tool for the numerical study of one dimensional quantum many-body systems, as the basis of the Density Matrix Renormalization Group method. Lattice Gauge Theories (LGT), in their Hamiltonian version, offer a challenging scenario for these techniques. While the dimensions and sizes of the systems amenable to TNS studies are still far from those achievable by 4-dimensional LGT tools, Tensor Networks can be readily used for problems which more standard techniques, such as Markov chain Monte Carlo simulations, cannot easily tackle. Examples of such problems are the presence of a chemical potential or out-of-equilibrium dynamics. We have explored the performance of Matrix Product States in the case of the Schwinger model, as a widely used ...
Multispectral Palmprint Recognition Using a Quaternion Matrix
Directory of Open Access Journals (Sweden)
Yafeng Li
2012-04-01
Full Text Available Palmprints have been widely studied for biometric recognition for many years. Traditionally, a white light source is used for illumination. Recently, multispectral imaging has drawn attention because of its high recognition accuracy. Multispectral palmprint systems can provide more discriminant information under different illuminations in a short time, thus they can achieve better recognition accuracy. Previously, multispectral palmprint images were taken as a kind of multi-modal biometrics, and the fusion scheme on the image level or matching score level was used. However, some spectral information will be lost during image level or matching score level fusion. In this study, we propose a new method for multispectral images based on a quaternion model which could fully utilize the multispectral information. Firstly, multispectral palmprint images captured under red, green, blue and near-infrared (NIR illuminations were represented by a quaternion matrix, then principal component analysis (PCA and discrete wavelet transform (DWT were applied respectively on the matrix to extract palmprint features. After that, Euclidean distance was used to measure the dissimilarity between different features. Finally, the sum of two distances and the nearest neighborhood classifier were employed for recognition decision. Experimental results showed that using the quaternion matrix can achieve a higher recognition rate. Given 3000 test samples from 500 palms, the recognition rate can be as high as 98.83%.
Deghosting based on the transmission matrix method
Wang, Benfeng; Wu, Ru-Shan; Chen, Xiaohong
2017-12-01
As the developments of seismic exploration and subsequent seismic exploitation advance, marine acquisition systems with towed streamers become an important seismic data acquisition method. But the existing air–water reflective interface can generate surface related multiples, including ghosts, which can affect the accuracy and performance of the following seismic data processing algorithms. Thus, we derive a deghosting method from a new perspective, i.e. using the transmission matrix (T-matrix) method instead of inverse scattering series. The T-matrix-based deghosting algorithm includes all scattering effects and is convergent absolutely. Initially, the effectiveness of the proposed method is demonstrated using synthetic data obtained from a designed layered model, and its noise-resistant property is also illustrated using noisy synthetic data contaminated by random noise. Numerical examples on complicated data from the open SMAART Pluto model and field marine data further demonstrate the validity and flexibility of the proposed method. After deghosting, low frequency components are recovered reasonably and the fake high frequency components are attenuated, and the recovered low frequency components will be useful for the subsequent full waveform inversion. The proposed deghosting method is currently suitable for two-dimensional towed streamer cases with accurate constant depth information and its extension into variable-depth streamers in three-dimensional cases will be studied in the future.
Random-matrix theory of quantum transport
Energy Technology Data Exchange (ETDEWEB)
Beenakker, C.W. [Instituut-Lorentz, University of Leiden, 2300 RA Leiden, (The Netherlands)
1997-07-01
This is a review of the statistical properties of the scattering matrix of a mesoscopic system. Two geometries are contrasted: A quantum dot and a disordered wire. The quantum dot is a confined region with a chaotic classical dynamics, which is coupled to two electron reservoirs via point contacts. The disordered wire also connects two reservoirs, either directly or via a point contact or tunnel barrier. One of the two reservoirs may be in the superconducting state, in which case conduction involves Andreev reflection at the interface with the superconductor. In the case of the quantum dot, the distribution of the scattering matrix is given by either Dyson{close_quote}s circular ensemble for ballistic point contacts or the Poisson kernel for point contacts containing a tunnel barrier. In the case of the disordered wire, the distribution of the scattering matrix is obtained from the Dorokhov-Mello-Pereyra-Kumar equation, which is a one-dimensional scaling equation. The equivalence is discussed with the nonlinear {sigma} model, which is a supersymmetric field theory of localization. The distribution of scattering matrices is applied to a variety of physical phenomena, including universal conductance fluctuations, weak localization, Coulomb blockade, sub-Poissonian shot noise, reflectionless tunneling into a superconductor, and giant conductance oscillations in a Josephson junction. {copyright} {ital 1997} {ital The American Physical Society}
Thermoforming of thermoplastic matrix composites. Part I
Energy Technology Data Exchange (ETDEWEB)
Harper, R.C.
1992-03-01
Long-fiber-reinforced polymer matrix composites find widespread use in a variety of commercial applications requiring properties that cannot be provided by unreinforced plastics or other common materials of construction. However, thermosetting matrix resins have long been plagued by production processes that are slow and difficult to automate. This has limited the use of long-fiber-reinforced composites to relatively low productivity applications in which higher production costs can be justified. Unreinforced thermoplastics, by their very nature, can easily be made into sheet form and processed into a variety of formed shapes by various pressure assisted thermoforming means. It is possible to incorporate various types of fiber reinforcement to suit the end use of the thermoformed shape. Recently developed thermoplastic resins can also sometimes correct physical property deficiencies in a thermoset matrix composite. Many forms of thermoplastic composite material now exist that meet all the requirements of present day automotive and aerospace parts. Some of these are presently in production, while others are still in the development stage. This opens the possibility that long-fiber-reinforced thermoplastics might break the barrier that has long limited the applications for fiber-reinforced composites. 37 refs., 8 figs., 5 tabs.
Multispectral palmprint recognition using a quaternion matrix.
Xu, Xingpeng; Guo, Zhenhua; Song, Changjiang; Li, Yafeng
2012-01-01
Palmprints have been widely studied for biometric recognition for many years. Traditionally, a white light source is used for illumination. Recently, multispectral imaging has drawn attention because of its high recognition accuracy. Multispectral palmprint systems can provide more discriminant information under different illuminations in a short time, thus they can achieve better recognition accuracy. Previously, multispectral palmprint images were taken as a kind of multi-modal biometrics, and the fusion scheme on the image level or matching score level was used. However, some spectral information will be lost during image level or matching score level fusion. In this study, we propose a new method for multispectral images based on a quaternion model which could fully utilize the multispectral information. Firstly, multispectral palmprint images captured under red, green, blue and near-infrared (NIR) illuminations were represented by a quaternion matrix, then principal component analysis (PCA) and discrete wavelet transform (DWT) were applied respectively on the matrix to extract palmprint features. After that, Euclidean distance was used to measure the dissimilarity between different features. Finally, the sum of two distances and the nearest neighborhood classifier were employed for recognition decision. Experimental results showed that using the quaternion matrix can achieve a higher recognition rate. Given 3000 test samples from 500 palms, the recognition rate can be as high as 98.83%.
ABCD Matrix Method a Case Study
Seidov, Zakir F; Yahalom, Asher
2004-01-01
In the Israeli Electrostatic Accelerator FEL, the distance between the accelerator's end and the wiggler's entrance is about 2.1 m, and 1.4 MeV electron beam is transported through this space using four similar quadrupoles (FODO-channel). The transfer matrix method (ABCD matrix method) was used for simulating the beam transport, a set of programs is written in the several programming languages (MATHEMATICA, MATLAB, MATCAD, MAPLE) and reasonable agreement is demonstrated between experimental results and simulations. Comparison of ABCD matrix method with the direct "numerical experiments" using EGUN, ELOP, and GPT programs with and without taking into account the space-charge effects showed the agreement to be good enough as well. Also the inverse problem of finding emittance of the electron beam at the S1 screen position (before FODO-channel), by using the spot image at S2 screen position (after FODO-channel) as function of quad currents, is considered. Spot and beam at both screens are described as tilted eel...
Typicality in random matrix product states
Garnerone, Silvano; de Oliveira, Thiago R.; Zanardi, Paolo
2010-03-01
Recent results suggest that the use of ensembles in statistical mechanics may not be necessary for isolated systems, since typically the states of the Hilbert space would have properties similar to those of the ensemble. Nevertheless, it is often argued that most of the states of the Hilbert space are nonphysical and not good descriptions of realistic systems. Therefore, to better understand the actual power of typicality it is important to ask if it is also a property of a set of physically relevant states. Here we address this issue, studying if and how typicality emerges in the set of matrix product states. We show analytically that typicality occurs for the expectation value of subsystems’ observables when the rank of the matrix product state scales polynomially with the size of the system with a power greater than 2. We illustrate this result numerically and present some indications that typicality may appear already for a linear scaling of the rank of the matrix product state.
Analyticity and the Holographic S-Matrix
Energy Technology Data Exchange (ETDEWEB)
Fitzpatrick, A.Liam; /Stanford U., Phys. Dept.; Kaplan, Jared; /SLAC
2012-04-03
We derive a simple relation between the Mellin amplitude for AdS/CFT correlation functions and the bulk S-Matrix in the flat spacetime limit, proving a conjecture of Penedones. As a consequence of the Operator Product Expansion, the Mellin amplitude for any unitary CFT must be a meromorphic function with simple poles on the real axis. This provides a powerful and suggestive handle on the locality vis-a-vis analyticity properties of the S-Matrix. We begin to explore analyticity by showing how the familiar poles and branch cuts of scattering amplitudes arise from the holographic description. For this purpose we compute examples of Mellin amplitudes corresponding to 1-loop and 2-loop Witten diagrams in AdS. We also examine the flat spacetime limit of conformal blocks, implicitly relating the S-Matrix program to the Bootstrap program for CFTs. We use this connection to show how the existence of small black holes in AdS leads to a universal prediction for the conformal block decomposition of the dual CFT.
Matrix product states for lattice field theories
Energy Technology Data Exchange (ETDEWEB)
Banuls, M.C.; Cirac, J.I. [Max-Planck-Institut fuer Quantenoptik (MPQ), Garching (Germany); Cichy, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Poznan Univ. (Poland). Faculty of Physics; Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Saito, H. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Tsukuba Univ., Ibaraki (Japan). Graduate School of Pure and Applied Sciences
2013-10-15
The term Tensor Network States (TNS) refers to a number of families of states that represent different ansaetze for the efficient description of the state of a quantum many-body system. Matrix Product States (MPS) are one particular case of TNS, and have become the most precise tool for the numerical study of one dimensional quantum many-body systems, as the basis of the Density Matrix Renormalization Group method. Lattice Gauge Theories (LGT), in their Hamiltonian version, offer a challenging scenario for these techniques. While the dimensions and sizes of the systems amenable to TNS studies are still far from those achievable by 4-dimensional LGT tools, Tensor Networks can be readily used for problems which more standard techniques, such as Markov chain Monte Carlo simulations, cannot easily tackle. Examples of such problems are the presence of a chemical potential or out-of-equilibrium dynamics. We have explored the performance of Matrix Product States in the case of the Schwinger model, as a widely used testbench for lattice techniques. Using finite-size, open boundary MPS, we are able to determine the low energy states of the model in a fully non-perturbativemanner. The precision achieved by the method allows for accurate finite size and continuum limit extrapolations of the ground state energy, but also of the chiral condensate and the mass gaps, thus showing the feasibility of these techniques for gauge theory problems.
Fatigue Behavior of a Functionally-Graded Titanium Matrix Composite
National Research Council Canada - National Science Library
Cunningham, Scott R
2005-01-01
Functionally-graded Titanium Matrix Composites are an attempt to utilize the high-strength properties of a titanium matrix composite with a monolithic alloy having the more practical machining qualities...
Involvement of extracellular matrix constituents in breast cancer
Energy Technology Data Exchange (ETDEWEB)
Lochter, Andre; Bissell, Mina J
1995-06-01
It has recently been established that the extracellular matrix is required for normal functional differentiation of mammary epithelia not only in culture, but also in vivo. The mechanisms by which extracellular matrix affects differentiation, as well as the nature of extracellular matrix constituents which have major impacts on mammary gland function, have only now begun to be dissected. The intricate variety of extracellular matrix-mediated events and the remarkable degree of plasticity of extracellular matrix structure and composition at virtually all times during ontogeny, make such studies difficult. Similarly, during carcinogenesis, the extracellular matrix undergoes gross alterations, the consequences of which are not yet precisely understood. Nevertheless, an increasing amount of data suggests that the extracellular matrix and extracellular matrix-receptors might participate in the control of most, if not all, of the successive stages of breast tumors, from appearance to progression and metastasis.
Revealing Slip Bands In A Metal-Matrix/Fiber Composite
Lerch, Bradley A.
1995-01-01
Experimental procedure includes heat treatments and metallographic techniques developed to facilitate studies of deformation of metal-matrix/fiber composite under stress. Reveals slip bands, indicative of plastic flow occurring in matrix during mechanical tests of specimens of composite.
Program For Analysis Of Metal-Matrix Composites
Murthy, P. L. N.; Mital, S. K.
1994-01-01
METCAN (METal matrix Composite ANalyzer) is computer program used to simulate computationally nonlinear behavior of high-temperature metal-matrix composite structural components in specific applications, providing comprehensive analyses of thermal and mechanical performances. Written in FORTRAN 77.