NASA Astrophysics Data System (ADS)
Zhang, Shunli; Zhang, Dinghua; Gong, Hao; Ghasemalizadeh, Omid; Wang, Ge; Cao, Guohua
2014-11-01
Iterative algorithms, such as the algebraic reconstruction technique (ART), are popular for image reconstruction. For iterative reconstruction, the area integral model (AIM) is more accurate for better reconstruction quality than the line integral model (LIM). However, the computation of the system matrix for AIM is more complex and time-consuming than that for LIM. Here, we propose a fast and accurate method to compute the system matrix for AIM. First, we calculate the intersection of each boundary line of a narrow fan-beam with pixels in a recursive and efficient manner. Then, by grouping the beam-pixel intersection area into six types according to the slopes of the two boundary lines, we analytically compute the intersection area of the narrow fan-beam with the pixels in a simple algebraic fashion. Overall, experimental results show that our method is about three times faster than the Siddon algorithm and about two times faster than the distance-driven model (DDM) in computation of the system matrix. The reconstruction speed of our AIM-based ART is also faster than the LIM-based ART that uses the Siddon algorithm and DDM-based ART, for one iteration. The fast reconstruction speed of our method was accomplished without compromising the image quality.
Micron Accurate Absolute Ranging System: Range Extension
NASA Technical Reports Server (NTRS)
Smalley, Larry L.; Smith, Kely L.
1999-01-01
The purpose of this research is to investigate Fresnel diffraction as a means of obtaining absolute distance measurements with micron or greater accuracy. It is believed that such a system would prove useful to the Next Generation Space Telescope (NGST) as a non-intrusive, non-contact measuring system for use with secondary concentrator station-keeping systems. The present research attempts to validate past experiments and develop ways to apply the phenomena of Fresnel diffraction to micron accurate measurement. This report discusses past research on the phenomena, and the basis of the use Fresnel diffraction distance metrology. The apparatus used in the recent investigations, experimental procedures used, preliminary results are discussed in detail. Continued research and equipment requirements on the extension of the effective range of the Fresnel diffraction systems is also described.
NASA Astrophysics Data System (ADS)
Somerville, W. R. C.; Auguié, B.; Le Ru, E. C.
2016-03-01
SMARTIES calculates the optical properties of oblate and prolate spheroidal particles, with comparable capabilities and ease-of-use as Mie theory for spheres. This suite of MATLAB codes provides a fully documented implementation of an improved T-matrix algorithm for the theoretical modelling of electromagnetic scattering by particles of spheroidal shape. Included are scripts that cover a range of scattering problems relevant to nanophotonics and plasmonics, including calculation of far-field scattering and absorption cross-sections for fixed incidence orientation, orientation-averaged cross-sections and scattering matrix, surface-field calculations as well as near-fields, wavelength-dependent near-field and far-field properties, and access to lower-level functions implementing the T-matrix calculations, including the T-matrix elements which may be calculated more accurately than with competing codes.
NASA Astrophysics Data System (ADS)
Zhao, Xiao-mei; Xie, Dong-fan; Li, Qi
2015-02-01
With the development of intelligent transport system, advanced information feedback strategies have been developed to reduce traffic congestion and enhance the capacity. However, previous strategies provide accurate information to travelers and our simulation results show that accurate information brings negative effects, especially in delay case. Because travelers prefer to the best condition route with accurate information, and delayed information cannot reflect current traffic condition but past. Then travelers make wrong routing decisions, causing the decrease of the capacity and the increase of oscillations and the system deviating from the equilibrium. To avoid the negative effect, bounded rationality is taken into account by introducing a boundedly rational threshold BR. When difference between two routes is less than the BR, routes have equal probability to be chosen. The bounded rationality is helpful to improve the efficiency in terms of capacity, oscillation and the gap deviating from the system equilibrium.
Accurate methods for large molecular systems.
Gordon, Mark S; Mullin, Jonathan M; Pruitt, Spencer R; Roskop, Luke B; Slipchenko, Lyudmila V; Boatz, Jerry A
2009-07-23
Three exciting new methods that address the accurate prediction of processes and properties of large molecular systems are discussed. The systematic fragmentation method (SFM) and the fragment molecular orbital (FMO) method both decompose a large molecular system (e.g., protein, liquid, zeolite) into small subunits (fragments) in very different ways that are designed to both retain the high accuracy of the chosen quantum mechanical level of theory while greatly reducing the demands on computational time and resources. Each of these methods is inherently scalable and is therefore eminently capable of taking advantage of massively parallel computer hardware while retaining the accuracy of the corresponding electronic structure method from which it is derived. The effective fragment potential (EFP) method is a sophisticated approach for the prediction of nonbonded and intermolecular interactions. Therefore, the EFP method provides a way to further reduce the computational effort while retaining accuracy by treating the far-field interactions in place of the full electronic structure method. The performance of the methods is demonstrated using applications to several systems, including benzene dimer, small organic species, pieces of the alpha helix, water, and ionic liquids.
Accurate upper body rehabilitation system using kinect.
Sinha, Sanjana; Bhowmick, Brojeshwar; Chakravarty, Kingshuk; Sinha, Aniruddha; Das, Abhijit
2016-08-01
The growing importance of Kinect as a tool for clinical assessment and rehabilitation is due to its portability, low cost and markerless system for human motion capture. However, the accuracy of Kinect in measuring three-dimensional body joint center locations often fails to meet clinical standards of accuracy when compared to marker-based motion capture systems such as Vicon. The length of the body segment connecting any two joints, measured as the distance between three-dimensional Kinect skeleton joint coordinates, has been observed to vary with time. The orientation of the line connecting adjoining Kinect skeletal coordinates has also been seen to differ from the actual orientation of the physical body segment. Hence we have proposed an optimization method that utilizes Kinect Depth and RGB information to search for the joint center location that satisfies constraints on body segment length and as well as orientation. An experimental study have been carried out on ten healthy participants performing upper body range of motion exercises. The results report 72% reduction in body segment length variance and 2° improvement in Range of Motion (ROM) angle hence enabling to more accurate measurements for upper limb exercises.
System Matrix Analysis for Computed Tomography Imaging.
Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo
2015-01-01
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.
System Matrix Analysis for Computed Tomography Imaging
Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo
2015-01-01
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. PMID:26575482
NASA Astrophysics Data System (ADS)
Alborzpour, Jonathan P.; Tew, David P.; Habershon, Scott
2016-11-01
Solution of the time-dependent Schrödinger equation using a linear combination of basis functions, such as Gaussian wavepackets (GWPs), requires costly evaluation of integrals over the entire potential energy surface (PES) of the system. The standard approach, motivated by computational tractability for direct dynamics, is to approximate the PES with a second order Taylor expansion, for example centred at each GWP. In this article, we propose an alternative method for approximating PES matrix elements based on PES interpolation using Gaussian process regression (GPR). Our GPR scheme requires only single-point evaluations of the PES at a limited number of configurations in each time-step; the necessity of performing often-expensive evaluations of the Hessian matrix is completely avoided. In applications to 2-, 5-, and 10-dimensional benchmark models describing a tunnelling coordinate coupled non-linearly to a set of harmonic oscillators, we find that our GPR method results in PES matrix elements for which the average error is, in the best case, two orders-of-magnitude smaller and, in the worst case, directly comparable to that determined by any other Taylor expansion method, without requiring additional PES evaluations or Hessian matrices. Given the computational simplicity of GPR, as well as the opportunities for further refinement of the procedure highlighted herein, we argue that our GPR methodology should replace methods for evaluating PES matrix elements using Taylor expansions in quantum dynamics simulations.
A unique, accurate LWIR optics measurement system
NASA Astrophysics Data System (ADS)
Fantone, Stephen D.; Orband, Daniel G.
2011-05-01
A compact low-cost LWIR test station has been developed that provides real time MTF testing of IR optical systems and EO imaging systems. The test station is intended to be operated by a technician and can be used to measure the focal length, blur spot size, distortion, and other metrics of system performance. The challenges and tradeoffs incorporated into this instrumentation will be presented. The test station performs the measurement of an IR lens or optical system's first order quantities (focal length, back focal length) including on and off-axis imaging performance (e.g., MTF, resolution, spot size) under actual test conditions to enable the simulation of their actual use. Also described is the method of attaining the needed accuracies so that derived calculations like focal length (EFL = image shift/tan(theta)) can be performed to the requisite accuracy. The station incorporates a patented video capture technology and measures MTF and blur characteristics using newly available lowcost LWIR cameras. This allows real time determination of the optical system performance enabling faster measurements, higher throughput and lower cost results than scanning systems. Multiple spectral filters are also accommodated within the test stations which facilitate performance evaluation under various spectral conditions.
Matrix-vector multiplication using digital partitioning for more accurate optical computing
NASA Technical Reports Server (NTRS)
Gary, C. K.
1992-01-01
Digital partitioning offers a flexible means of increasing the accuracy of an optical matrix-vector processor. This algorithm can be implemented with the same architecture required for a purely analog processor, which gives optical matrix-vector processors the ability to perform high-accuracy calculations at speeds comparable with or greater than electronic computers as well as the ability to perform analog operations at a much greater speed. Digital partitioning is compared with digital multiplication by analog convolution, residue number systems, and redundant number representation in terms of the size and the speed required for an equivalent throughput as well as in terms of the hardware requirements. Digital partitioning and digital multiplication by analog convolution are found to be the most efficient alogrithms if coding time and hardware are considered, and the architecture for digital partitioning permits the use of analog computations to provide the greatest throughput for a single processor.
The potential of more accurate InSAR covariance matrix estimation for land cover mapping
NASA Astrophysics Data System (ADS)
Jiang, Mi; Yong, Bin; Tian, Xin; Malhotra, Rakesh; Hu, Rui; Li, Zhiwei; Yu, Zhongbo; Zhang, Xinxin
2017-04-01
Synthetic aperture radar (SAR) and Interferometric SAR (InSAR) provide both structural and electromagnetic information for the ground surface and therefore have been widely used for land cover classification. However, relatively few studies have developed analyses that investigate SAR datasets over richly textured areas where heterogeneous land covers exist and intermingle over short distances. One of main difficulties is that the shapes of the structures in a SAR image cannot be represented in detail as mixed pixels are likely to occur when conventional InSAR parameter estimation methods are used. To solve this problem and further extend previous research into remote monitoring of urban environments, we address the use of accurate InSAR covariance matrix estimation to improve the accuracy of land cover mapping. The standard and updated methods were tested using the HH-polarization TerraSAR-X dataset and compared with each other using the random forest classifier. A detailed accuracy assessment complied for six types of surfaces shows that the updated method outperforms the standard approach by around 9%, with an overall accuracy of 82.46% over areas with rich texture in Zhuhai, China. This paper demonstrates that the accuracy of land cover mapping can benefit from the 3 enhancement of the quality of the observations in addition to classifiers selection and multi-source data ingratiation reported in previous studies.
NASA Astrophysics Data System (ADS)
Wu, Su-Yong; Long, Xing-Wu; Yang, Kai-Yong
2009-09-01
To improve the current status of home multilayer optical coating design with low speed and poor efficiency when a large layer number occurs, the accurate calculation and fast realization of merit function’s gradient and Hesse matrix is pointed out. Based on the matrix method to calculate the spectral properties of multilayer optical coating, an analytic model is established theoretically. And the corresponding accurate and fast computation is successfully achieved by programming with Matlab. Theoretical and simulated results indicate that this model is mathematically strict and accurate, and its maximal precision can reach floating-point operations in the computer, with short time and fast speed. Thus it is very suitable to improve the optimal search speed and efficiency of local optimization methods based on the derivatives of merit function. It has outstanding performance in multilayer optical coating design with a large layer number.
Ultrasonic system for accurate distance measurement in the air.
Licznerski, Tomasz J; Jaroński, Jarosław; Kosz, Dariusz
2011-12-01
This paper presents a system that accurately measures the distance travelled by ultrasound waves through the air. The simple design of the system and its obtained accuracy provide a tool for non-contact distance measurements required in the laser's optical system that investigates the surface of the eyeball.
NASA Astrophysics Data System (ADS)
Wang, Benfeng; Jakobsen, Morten; Wu, Ru-Shan; Lu, Wenkai; Chen, Xiaohong
2017-03-01
Full waveform inversion (FWI) has been regarded as an effective tool to build the velocity model for the following pre-stack depth migration. Traditional inversion methods are built on Born approximation and are initial model dependent, while this problem can be avoided by introducing Transmission matrix (T-matrix), because the T-matrix includes all orders of scattering effects. The T-matrix can be estimated from the spatial aperture and frequency bandwidth limited seismic data using linear optimization methods. However the full T-matrix inversion method (FTIM) is always required in order to estimate velocity perturbations, which is very time consuming. The efficiency can be improved using the previously proposed inverse thin-slab propagator (ITSP) method, especially for large scale models. However, the ITSP method is currently designed for smooth media, therefore the estimation results are unsatisfactory when the velocity perturbation is relatively large. In this paper, we propose a domain decomposition method (DDM) to improve the efficiency of the velocity estimation for models with large perturbations, as well as guarantee the estimation accuracy. Numerical examples for smooth Gaussian ball models and a reservoir model with sharp boundaries are performed using the ITSP method, the proposed DDM and the FTIM. The estimated velocity distributions, the relative errors and the elapsed time all demonstrate the validity of the proposed DDM.
Calibration Techniques for Accurate Measurements by Underwater Camera Systems
Shortis, Mark
2015-01-01
Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems. PMID:26690172
Calibration Techniques for Accurate Measurements by Underwater Camera Systems.
Shortis, Mark
2015-12-07
Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems.
Embedded systems for controlling LED matrix displays
NASA Astrophysics Data System (ADS)
Marghescu, Cristina; Drumea, Andrei
2016-12-01
LED matrix displays are a common presence in everyday life - they can be found in trains, buses, tramways, office information tables or outdoor media. The structure of the display unit is similar for all these devices, a matrix of light emitting diodes coupled between row and column lines, but there are many options for the display controller that switches these lines. Present paper analyzes different types of embedded systems that can control the LED matrix, based on single board computers, on microcontrollers with different peripheral devices or with programmable logic devices like field programmable gate arrays with implemented soft processor cores. Scalability, easiness of implementation and costs are analyzed for all proposed solutions.
Connective stability of nonlinear matrix systems
NASA Technical Reports Server (NTRS)
Siljak, D. D.
1974-01-01
Consideration of stability under structural perturbations of free dynamic systems described by the differential equation dx/dt = A(t,x)x, where the matrix A(t,x) has time-varying nonlinear elements. The concept of 'connective stability' is introduced to study the structural properties of competitive-cooperative nonlinear matrix systems. It is shown that stability reliability in such systems is high and that they remain stable despite time-varying (including 'on-off') interaction among individual agents present in the system. The results obtained can be used to study stability aspects of mathematical models arising in as diverse fields as economics, biology, arms races, and transistor circuits.
NASA Technical Reports Server (NTRS)
Ellison, Donald; Conway, Bruce; Englander, Jacob
2015-01-01
A significant body of work exists showing that providing a nonlinear programming (NLP) solver with expressions for the problem constraint gradient substantially increases the speed of program execution and can also improve the robustness of convergence, especially for local optimizers. Calculation of these derivatives is often accomplished through the computation of spacecraft's state transition matrix (STM). If the two-body gravitational model is employed as is often done in the context of preliminary design, closed form expressions for these derivatives may be provided. If a high fidelity dynamics model, that might include perturbing forces such as the gravitational effect from multiple third bodies and solar radiation pressure is used then these STM's must be computed numerically. We present a method for the power hardward model and a full ephemeris model. An adaptive-step embedded eight order Dormand-Prince numerical integrator is discussed and a method for the computation of the time of flight derivatives in this framework is presented. The use of these numerically calculated derivatieves offer a substantial improvement over finite differencing in the context of a global optimizer. Specifically the inclusion of these STM's into the low thrust missiondesign tool chain in use at NASA Goddard Spaceflight Center allows for an increased preliminary mission design cadence.
Simple and accurate sum rules for highly relativistic systems
NASA Astrophysics Data System (ADS)
Cohen, Scott M.
2005-03-01
In this paper, I consider the Bethe and Thomas-Reiche-Kuhn sum rules, which together form the foundation of Bethe's theory of energy loss from fast charged particles to matter. For nonrelativistic target systems, the use of closure leads directly to simple expressions for these quantities. In the case of relativistic systems, on the other hand, the calculation of sum rules is fraught with difficulties. Various perturbative approaches have been used over the years to obtain relativistic corrections, but these methods fail badly when the system in question is very strongly bound. Here, I present an approach that leads to relatively simple expressions yielding accurate sums, even for highly relativistic many-electron systems. I also offer an explanation for the difference between relativistic and nonrelativistic sum rules in terms of the Zitterbewegung of the electrons.
Accurate and simple calibration of DLP projector systems
NASA Astrophysics Data System (ADS)
Wilm, Jakob; Olesen, Oline V.; Larsen, Rasmus
2014-03-01
Much work has been devoted to the calibration of optical cameras, and accurate and simple methods are now available which require only a small number of calibration targets. The problem of obtaining these parameters for light projectors has not been studied as extensively and most current methods require a camera and involve feature extraction from a known projected pattern. In this work we present a novel calibration technique for DLP Projector systems based on phase shifting profilometry projection onto a printed calibration target. In contrast to most current methods, the one presented here does not rely on an initial camera calibration, and so does not carry over the error into projector calibration. A radial interpolation scheme is used to convert features coordinates into projector space, thereby allowing for a very accurate procedure. This allows for highly accurate determination of parameters including lens distortion. Our implementation acquires printed planar calibration scenes in less than 1s. This makes our method both fast and convenient. We evaluate our method in terms of reprojection errors and structured light image reconstruction quality.
A Highly Accurate Face Recognition System Using Filtering Correlation
NASA Astrophysics Data System (ADS)
Watanabe, Eriko; Ishikawa, Sayuri; Kodate, Kashiko
2007-09-01
The authors previously constructed a highly accurate fast face recognition optical correlator (FARCO) [E. Watanabe and K. Kodate: Opt. Rev. 12 (2005) 460], and subsequently developed an improved, super high-speed FARCO (S-FARCO), which is able to process several hundred thousand frames per second. The principal advantage of our new system is its wide applicability to any correlation scheme. Three different configurations were proposed, each depending on correlation speed. This paper describes and evaluates a software correlation filter. The face recognition function proved highly accurate, seeing that a low-resolution facial image size (64 × 64 pixels) has been successfully implemented. An operation speed of less than 10 ms was achieved using a personal computer with a central processing unit (CPU) of 3 GHz and 2 GB memory. When we applied the software correlation filter to a high-security cellular phone face recognition system, experiments on 30 female students over a period of three months yielded low error rates: 0% false acceptance rate and 2% false rejection rate. Therefore, the filtering correlation works effectively when applied to low resolution images such as web-based images or faces captured by a monitoring camera.
A fast and accurate FPGA based QRS detection system.
Shukla, Ashish; Macchiarulo, Luca
2008-01-01
An accurate Field Programmable Gate Array (FPGA) based ECG Analysis system is described in this paper. The design, based on a popular software based QRS detection algorithm, calculates the threshold value for the next peak detection cycle, from the median of eight previously detected peaks. The hardware design has accuracy in excess of 96% in detecting the beats correctly when tested with a subset of five 30 minute data records obtained from the MIT-BIH Arrhythmia database. The design, implemented using a proprietary design tool (System Generator), is an extension of our previous work and uses 76% resources available in a small-sized FPGA device (Xilinx Spartan xc3s500), has a higher detection accuracy as compared to our previous design and takes almost half the analysis time in comparison to software based approach.
Accurate determination of heteroclinic orbits in chaotic dynamical systems
NASA Astrophysics Data System (ADS)
Li, Jizhou; Tomsovic, Steven
2017-03-01
Accurate calculation of heteroclinic and homoclinic orbits can be of significant importance in some classes of dynamical system problems. Yet for very strongly chaotic systems initial deviations from a true orbit will be magnified by a large exponential rate making direct computational methods fail quickly. In this paper, a method is developed that avoids direct calculation of the orbit by making use of the well-known stability property of the invariant unstable and stable manifolds. Under an area-preserving map, this property assures that any initial deviation from the stable (unstable) manifold collapses onto them under inverse (forward) iterations of the map. Using a set of judiciously chosen auxiliary points on the manifolds, long orbit segments can be calculated using the stable and unstable manifold intersections of the heteroclinic (homoclinic) tangle. Detailed calculations using the example of the kicked rotor are provided along with verification of the relation between action differences and certain areas bounded by the manifolds.
Motion Control for Nonholonomic Systems on Matrix Lie Groups
1998-01-01
representations of systems on a certain nilpotent matrix group. After studying the technique of nilpotentization in the setting of systems on matrix ...the technique of nilpotentization in the setting of systems on matrix Lie groups we show how motion control laws derived for nilpotent systems can be...of systems on a certain nilpotent matrix group. After studying the technique of nilpotentization in the setting of systems on matrix Lie groups we show
Yao, Y. X.; Liu, J.; Liu, C.; Lu, W. C.; Wang, C. Z.; Ho, K. M.
2015-01-01
We present an efficient method for calculating the electronic structure and total energy of strongly correlated electron systems. The method extends the traditional Gutzwiller approximation for one-particle operators to the evaluation of the expectation values of two particle operators in the many-electron Hamiltonian. The method is free of adjustable Coulomb parameters, and has no double counting issues in the calculation of total energy, and has the correct atomic limit. We demonstrate that the method describes well the bonding and dissociation behaviors of the hydrogen and nitrogen clusters, as well as the ammonia composed of hydrogen and nitrogen atoms. We also show that the method can satisfactorily tackle great challenging problems faced by the density functional theory recently discussed in the literature. The computational workload of our method is similar to the Hartree-Fock approach while the results are comparable to high-level quantum chemistry calculations. PMID:26315767
Yao, Y X; Liu, J; Liu, C; Lu, W C; Wang, C Z; Ho, K M
2015-08-28
We present an efficient method for calculating the electronic structure and total energy of strongly correlated electron systems. The method extends the traditional Gutzwiller approximation for one-particle operators to the evaluation of the expectation values of two particle operators in the many-electron Hamiltonian. The method is free of adjustable Coulomb parameters, and has no double counting issues in the calculation of total energy, and has the correct atomic limit. We demonstrate that the method describes well the bonding and dissociation behaviors of the hydrogen and nitrogen clusters, as well as the ammonia composed of hydrogen and nitrogen atoms. We also show that the method can satisfactorily tackle great challenging problems faced by the density functional theory recently discussed in the literature. The computational workload of our method is similar to the Hartree-Fock approach while the results are comparable to high-level quantum chemistry calculations.
Yao, Y. X.; Liu, J.; Liu, C.; ...
2015-08-28
We present an efficient method for calculating the electronic structure and total energy of strongly correlated electron systems. The method extends the traditional Gutzwiller approximation for one-particle operators to the evaluation of the expectation values of two particle operators in the many-electron Hamiltonian. The method is free of adjustable Coulomb parameters, and has no double counting issues in the calculation of total energy, and has the correct atomic limit. We demonstrate that the method describes well the bonding and dissociation behaviors of the hydrogen and nitrogen clusters, as well as the ammonia composed of hydrogen and nitrogen atoms. We alsomore » show that the method can satisfactorily tackle great challenging problems faced by the density functional theory recently discussed in the literature. The computational workload of our method is similar to the Hartree-Fock approach while the results are comparable to high-level quantum chemistry calculations.« less
Yao, Y. X.; Liu, J.; Liu, C.; Lu, W. C.; Wang, C. Z.; Ho, K. M.
2015-08-28
We present an efficient method for calculating the electronic structure and total energy of strongly correlated electron systems. The method extends the traditional Gutzwiller approximation for one-particle operators to the evaluation of the expectation values of two particle operators in the many-electron Hamiltonian. The method is free of adjustable Coulomb parameters, and has no double counting issues in the calculation of total energy, and has the correct atomic limit. We demonstrate that the method describes well the bonding and dissociation behaviors of the hydrogen and nitrogen clusters, as well as the ammonia composed of hydrogen and nitrogen atoms. We also show that the method can satisfactorily tackle great challenging problems faced by the density functional theory recently discussed in the literature. The computational workload of our method is similar to the Hartree-Fock approach while the results are comparable to high-level quantum chemistry calculations.
Personalized Orthodontic Accurate Tooth Arrangement System with Complete Teeth Model.
Cheng, Cheng; Cheng, Xiaosheng; Dai, Ning; Liu, Yi; Fan, Qilei; Hou, Yulin; Jiang, Xiaotong
2015-09-01
The accuracy, validity and lack of relation information between dental root and jaw in tooth arrangement are key problems in tooth arrangement technology. This paper aims to describe a newly developed virtual, personalized and accurate tooth arrangement system based on complete information about dental root and skull. Firstly, a feature constraint database of a 3D teeth model is established. Secondly, for computed simulation of tooth movement, the reference planes and lines are defined by the anatomical reference points. The matching mathematical model of teeth pattern and the principle of the specific pose transformation of rigid body are fully utilized. The relation of position between dental root and alveolar bone is considered during the design process. Finally, the relative pose relationships among various teeth are optimized using the object mover, and a personalized therapeutic schedule is formulated. Experimental results show that the virtual tooth arrangement system can arrange abnormal teeth very well and is sufficiently flexible. The relation of position between root and jaw is favorable. This newly developed system is characterized by high-speed processing and quantitative evaluation of the amount of 3D movement of an individual tooth.
Accurate measurement of RF exposure from emerging wireless communication systems
NASA Astrophysics Data System (ADS)
Letertre, Thierry; Monebhurrun, Vikass; Toffano, Zeno
2013-04-01
Isotropic broadband probes or spectrum analyzers (SAs) may be used for the measurement of rapidly varying electromagnetic fields generated by emerging wireless communication systems. In this paper this problematic is investigated by comparing the responses measured by two different isotropic broadband probes typically used to perform electric field (E-field) evaluations. The broadband probes are submitted to signals with variable duty cycles (DC) and crest factors (CF) either with or without Orthogonal Frequency Division Multiplexing (OFDM) modulation but with the same root-mean-square (RMS) power. The two probes do not provide accurate enough results for deterministic signals such as Worldwide Interoperability for Microwave Access (WIMAX) or Long Term Evolution (LTE) as well as for non-deterministic signals such as Wireless Fidelity (WiFi). The legacy measurement protocols should be adapted to cope for the emerging wireless communication technologies based on the OFDM modulation scheme. This is not easily achieved except when the statistics of the RF emission are well known. In this case the measurement errors are shown to be systematic and a correction factor or calibration can be applied to obtain a good approximation of the total RMS power.
Digital system accurately controls velocity of electromechanical drive
NASA Technical Reports Server (NTRS)
Nichols, G. B.
1965-01-01
Digital circuit accurately regulates electromechanical drive mechanism velocity. The gain and phase characteristics of digital circuits are relatively unimportant. Control accuracy depends only on the stability of the input signal frequency.
Saha, Krishnendu; Straus, Kenneth J.; Glick, Stephen J.; Chen, Yu.
2014-08-28
To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.
Generating Nice Linear Systems for Matrix Gaussian Elimination
ERIC Educational Resources Information Center
Homewood, L. James
2004-01-01
In this article an augmented matrix that represents a system of linear equations is called nice if a sequence of elementary row operations that reduces the matrix to row-echelon form, through matrix Gaussian elimination, does so by restricting all entries to integers in every step. Many instructors wish to use the example of matrix Gaussian…
Two-Matrix Photometer Control System
NASA Astrophysics Data System (ADS)
Zhantayev, Zh. Sh.; Kuratov, K. S.; Seytimbetov, A. M.; Mailybayev, A. G.; Alimgazinova, N. Sh.; Manapbayeva, A. B.; Kuratova, A. K.; Iztleuov, N. T.
In this paper astronomical two-matrix photometer is described. It differs from common one CCD camera photometers by using the second CCD camera. It enables simultaneously to carry out the studied star and standard star light inputs measurements. The second camera application enables significantly to increase measurements accuracy and at least twice time decrease of one star observation. The significant increase of measurements accuracy is reached by carrying out simultaneous observations, and errors caused by the Earth atmosphere fluctuation are the same as for studied star so for standard star. Time decrease is reached by carrying out both stars simultaneous observations. In the paper photometer's optical mechanics scheme is given. The motion mechanism of receiving and recording block with micrometer screw rotated by stepping motor is described. It is demonstrated that exact coordinates of matrix position attached to clutch on micrometer screw are shoot by absolute magnetic encoder. The applied two-matrix photometer control system electronic equipment is described. The photometer operation control algorithm installed on Tien-Shan astronomical observatory 1-meter telescope is presented.
Boost matrix converters in clean energy systems
NASA Astrophysics Data System (ADS)
Karaman, Ekrem
This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid. Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype.
Theoretical Studies of the Relaxation Matrix for Molecular Systems
NASA Astrophysics Data System (ADS)
Ma, Qiancheng; Boulet, C.
2016-06-01
The phenomenon of collisional transfer of intensity due to line mixing has an increasing importance for atmospheric monitoring. From a theoretical point of view, all relevant information about the collisional processes is contained in the relaxation matrix where the diagonal elements give half-widths and shifts, and the off-diagonal elements correspond to line interferences. For simple systems such as those consisting of diatom-atom or diatom-diatom, accurate fully quantum calculations based on interaction potentials are feasible. However, fully quantum calculations become unrealistic for more complex systems. On the other hand, the semi-classical Robert-Bonamy formalism, which has been widely used to calculate half-widths and shifts for decades, fails in calculating the off-diagonal matrix elements resulting from applying the isolated line approximation. As a result, in order to simulate atmospheric spectra where the effects from line mixing are important, semi-empirical fitting or scaling laws such as the energy corrected sudden (ECS) and the infinite order sudden (IOS) models are commonly used. Recently, we have found that in developing this semi-classical line shape theory, to rely on the isolated line approximation is not necessary. By eliminating this unjustified assumption, and accurately evaluating matrix elements of the exponential operators, we have developed a more capable formalism that enables one not only to reduce uncertainties for calculated half-widths and shifts, but also to calculate the whole relaxation matrix. This implies that we can address the line mixing with the semi-classical theory based on interaction potentials between molecular absorber and molecular perturber. We have applied this formalism for Raman and infrared spectra of linear and asymmetric-top molecules. Recently, the method has been extended into symmetric-tops with inverse symmetry such as the NH3 molecule. Our calculated half-widths of NH3 lines in the νb{1} and the pure
Digraph matrix analysis applications to systems interactions
Alesso, H.P.; Altenbach, T.; Lappa, D.; Kimura, C.; Sacks, I.J.; Ashmore, B.C.; Fromme, D.; Smith, C.F.; Williams, W.
1984-01-01
Complex events such as Three Mile Island-2, Brown's Ferry-3 and Crystal River-3 have demonstrated that previously unidentified system interdependencies can be important to safety. A major aspect of these events was dependent faults (common cause/mode failures). The term systems interactions has been introduced by the Nuclear Regulatory Commission (NRC) to identify the concepts of spatial and functional coupling of systems which can lead to system interdependencies. Spatial coupling refers to dependencies resulting from a shared environmental condition; functional coupling refers to both dependencies resulting from components shared between safety and/or support systems, and to dependencies involving human actions. The NRC is currently developing guidelines to search for and evaluate adverse systems interactions at light water reactors. One approach utilizes graph theoretical methods and is called digraph matrix analysis (DMA). This methodology has been specifically tuned to the systems interaction problem. The objective of this paper is to present results from two DMA applications and to contrast them with the results from more traditional fault tree approaches.
Teng, Shih-Hua; Chen, Chung-Ming; Lee, Meng-Rui; Lee, Tai-Fen; Chien, Kun-Yi; Teng, Lee-Jene
2013-01-01
Among 36 Mycobacterium masilliense and 22 M. abscessus isolates identified by erm(41) PCR and sequencing analysis of rpoB and 23S rRNA genes, the rate of accurate differentiation between these two subspecies was 100% by cluster analysis of spectra generated by Bruker Biotyper matrix-assisted laser desorption ionization–time of flight mass spectrometry. PMID:23824775
Strategy for accurate liver intervention by an optical tracking system
Lin, Qinyong; Yang, Rongqian; Cai, Ken; Guan, Peifeng; Xiao, Weihu; Wu, Xiaoming
2015-01-01
Image-guided navigation for radiofrequency ablation of liver tumors requires the accurate guidance of needle insertion into a tumor target. The main challenge of image-guided navigation for radiofrequency ablation of liver tumors is the occurrence of liver deformations caused by respiratory motion. This study reports a strategy of real-time automatic registration to track custom fiducial markers glued onto the surface of a patient’s abdomen to find the respiratory phase, in which the static preoperative CT is performed. Custom fiducial markers are designed. Real-time automatic registration method consists of the automatic localization of custom fiducial markers in the patient and image spaces. The fiducial registration error is calculated in real time and indicates if the current respiratory phase corresponds to the phase of the static preoperative CT. To demonstrate the feasibility of the proposed strategy, a liver simulator is constructed and two volunteers are involved in the preliminary experiments. An ex-vivo porcine liver model is employed to further verify the strategy for liver intervention. Experimental results demonstrate that real-time automatic registration method is rapid, accurate, and feasible for capturing the respiratory phase from which the static preoperative CT anatomical model is generated by tracking the movement of the skin-adhered custom fiducial markers. PMID:26417501
Space-Dynamically Responding Ultrasonic Matrix System
NASA Technical Reports Server (NTRS)
Guigne, Jacques; Yi, Hu Chun
2008-01-01
Space-Dynamically Responding Ultrasonic Matrix System (SpaceDRUMS) comprises a suite of hardware that enables containerless processing (samples of experimental materials can be processed without ever touching a container wall). Using a collection of 20 acoustic beam emitters, SpaceDRUMS can completely suspend a baseball-sized solid or liquid sample during combustion or heat-based synthesis. Because the samples never contact the container walls, materials can be produced in microgravity with an unparalleled quality of shape and composition. The ultimate goal of the SpaceDRUMS hardware is to assist with the development of advanced materials of a commercial quantity and quality, using the space-based experiments to guide development of manufacturing processes on Earth. T
A new accurate pill recognition system using imprint information
NASA Astrophysics Data System (ADS)
Chen, Zhiyuan; Kamata, Sei-ichiro
2013-12-01
Great achievements in modern medicine benefit human beings. Also, it has brought about an explosive growth of pharmaceuticals that current in the market. In daily life, pharmaceuticals sometimes confuse people when they are found unlabeled. In this paper, we propose an automatic pill recognition technique to solve this problem. It functions mainly based on the imprint feature of the pills, which is extracted by proposed MSWT (modified stroke width transform) and described by WSC (weighted shape context). Experiments show that our proposed pill recognition method can reach an accurate rate up to 92.03% within top 5 ranks when trying to classify more than 10 thousand query pill images into around 2000 categories.
Accurate Compensation of Attitude Angle Error in a Dual-Axis Rotation Inertial Navigation System
Jiang, Rui; Yang, Gongliu; Zou, Rui; Wang, Jing; Li, Jing
2017-01-01
In the dual-axis rotation inertial navigation system (INS), besides the gyro error, accelerometer error, rolling misalignment angle error, and the gimbal angle error, the shaft swing angle and the axis non-orthogonal angle also affect the attitude accuracy. Through the analysis of the structure, we can see that the shaft swing angle and axis non-orthogonal angle will produce coning errors which cause the fluctuation of the attitude. According to the analysis of the rotation vector, it can be seen that the coning error will generate additional drift velocity along the rotating shaft, which can reduce the navigation precision of the system. In this paper, based on the establishment of the modulation average frame, the vector projection is carried out, and then the attitude conversion matrix and the attitude error matrix mainly including the shaft swing angle and axis non-orthogonal are obtained. Because the attitude angles are given under the static condition, the shaft swing angle and the axis non-orthogonal angle are estimated by the static Kalman filter (KF). This kind of KF method has been widely recognized as the standard optimal estimation tool for estimating the parameters such as coning angles (α1 , α2), initial phase angles (ϕ1,ϕ2), and the non-perpendicular angle (η). In order to carry out the system level verification, a dual axis rotation INS is designed. Through simulation and experiments, the results show that the amplitudes of the attitude angles’ variation are reduced by about 20%–30% when the shaft rotates. The attitude error equation is reasonably simplified and the calibration method is accurate enough. The attitude accuracy is further improved. PMID:28304354
Accurate Compensation of Attitude Angle Error in a Dual-Axis Rotation Inertial Navigation System.
Jiang, Rui; Yang, Gongliu; Zou, Rui; Wang, Jing; Li, Jing
2017-03-17
In the dual-axis rotation inertial navigation system (INS), besides the gyro error, accelerometer error, rolling misalignment angle error, and the gimbal angle error, the shaft swing angle and the axis non-orthogonal angle also affect the attitude accuracy. Through the analysis of the structure, we can see that the shaft swing angle and axis non-orthogonal angle will produce coning errors which cause the fluctuation of the attitude. According to the analysis of the rotation vector, it can be seen that the coning error will generate additional drift velocity along the rotating shaft, which can reduce the navigation precision of the system. In this paper, based on the establishment of the modulation average frame, the vector projection is carried out, and then the attitude conversion matrix and the attitude error matrix mainly including the shaft swing angle and axis non-orthogonal are obtained. Because the attitude angles are given under the static condition, the shaft swing angle and the axis non-orthogonal angle are estimated by the static Kalman filter (KF). This kind of KF method has been widely recognized as the standard optimal estimation tool for estimating the parameters such as coning angles (α₁ , α₂), initial phase angles (ϕ₁,ϕ₂), and the non-perpendicular angle (η). In order to carry out the system level verification, a dual axis rotation INS is designed. Through simulation and experiments, the results show that the amplitudes of the attitude angles' variation are reduced by about 20%-30% when the shaft rotates. The attitude error equation is reasonably simplified and the calibration method is accurate enough. The attitude accuracy is further improved.
Systems and methods for deactivating a matrix converter
Ransom, Ray M.
2013-04-02
Systems and methods are provided for deactivating a matrix conversion module. An electrical system comprises an alternating current (AC) interface, a matrix conversion module coupled to the AC interface, an inductive element coupled between the AC interface and the matrix conversion module, and a control module. The control module is coupled to the matrix conversion module, and in response to a shutdown condition, the control module is configured to operate the matrix conversion module to deactivate the first conversion module when a magnitude of a current through the inductive element is less than a threshold value.
Towards accurate quantum simulations of large systems with small computers
NASA Astrophysics Data System (ADS)
Yang, Yonggang
2017-01-01
Numerical simulations are important for many systems. In particular, various standard computer programs have been developed for solving the quantum Schrödinger equations. However, the accuracy of these calculations is limited by computer capabilities. In this work, an iterative method is introduced to enhance the accuracy of these numerical calculations, which is otherwise prohibitive by conventional methods. The method is easily implementable and general for many systems.
Towards accurate quantum simulations of large systems with small computers.
Yang, Yonggang
2017-01-24
Numerical simulations are important for many systems. In particular, various standard computer programs have been developed for solving the quantum Schrödinger equations. However, the accuracy of these calculations is limited by computer capabilities. In this work, an iterative method is introduced to enhance the accuracy of these numerical calculations, which is otherwise prohibitive by conventional methods. The method is easily implementable and general for many systems.
Towards accurate quantum simulations of large systems with small computers
Yang, Yonggang
2017-01-01
Numerical simulations are important for many systems. In particular, various standard computer programs have been developed for solving the quantum Schrödinger equations. However, the accuracy of these calculations is limited by computer capabilities. In this work, an iterative method is introduced to enhance the accuracy of these numerical calculations, which is otherwise prohibitive by conventional methods. The method is easily implementable and general for many systems. PMID:28117366
An accurate continuous calibration system for high voltage current transformer
Tong Yue; Li Binhong
2011-02-15
A continuous calibration system for high voltage current transformers is presented in this paper. The sensor of this system is based on a kind of electronic instrument current transformer, which is a clamp-shape air core coil. This system uses an optical fiber transmission system for its signal transmission and power supply. Finally the digital integrator and fourth-order convolution window algorithm as error calculation methods are realized by the virtual instrument with a personal computer. It is found that this system can calibrate a high voltage current transformer while energized, which means avoiding a long calibrating period in the power system and the loss of power metering expense. At the same time, it has a wide dynamic range and frequency band, and it can achieve a high accuracy measurement in a complex electromagnetic field environment. The experimental results and the on-site operation results presented in the last part of the paper, prove that it can reach the 0.05 accuracy class and is easy to operate on site.
Accurate aircraft wind measurements using the global positioning system (GPS)
Dobosy, R.J.; Crawford, T.L., McMillen, R.T., Dumas, E.J.
1996-11-01
High accuracy measurements of the spatial distribution of wind speed are required in the study of turbulent exchange between the atmosphere and the earth. The use of a differential global positioning system (GPS) to determine the sensor velocity vector component of wind speed is discussed in this paper. The results of noise and rocking testing are summarized, and fluxes obtained from the GPS-based methods are compared to those measured from systems on towers and airplanes. The GPS-based methods provided usable measurements that compared well with tower and aircraft data at a significantly lower cost. 21 refs., 1 fig., 2 tabs.
High-Speed Computer-Controlled Switch-Matrix System
NASA Technical Reports Server (NTRS)
Spisz, E.; Cory, B.; Ho, P.; Hoffman, M.
1985-01-01
High-speed computer-controlled switch-matrix system developed for communication satellites. Satellite system controlled by onboard computer and all message-routing functions between uplink and downlink beams handled by newly developed switch-matrix system. Message requires only 2-microsecond interconnect period, repeated every millisecond.
Accurate universal parameterization of absorption cross sections III - light systems
NASA Astrophysics Data System (ADS)
Tripathi, R. K.; Cucinotta, F. A.; Wilson, J. W.
1999-09-01
Our prior nuclear absorption cross sections model [R.K. Tripathi, F.A. Cucinotta, J.W. Wilson, Nucl. Instr. and Meth. B 117 (1996) 347; R.K. Tripathi, J.W. Wilson, F.A. Cucinotta, Nucl. Instr. and Meth. B 129 (1997) 11] is extended for light systems ( A ⩽ 4) where either both projectile and target are light particles or one is light particle and the other is medium or heavy nucleus. The agreement with experiment is excellent for these cases as well. Present work in combination with our original model provides a comprehensive picture of absorption cross sections for light, medium and heavy systems. As a result the extended model can reliably be used in all studies where there is a need for absorption cross sections.
Micron-Accurate Laser Fresnel-Diffraction Ranging System
NASA Technical Reports Server (NTRS)
Lehner, David; Campbell, Jonathan; Smith, Kelly; Sanders, Alvin; Allison, Stephen; Smaley, Larry
2008-01-01
Two versions of an optoelectronic system undergoing development are depicted. The system is expected to be capable of measuring a distance between 2 and 10 m with an error of no more than 1 micrometer. The system would be designed to exploit Fresnel diffraction of a laser beam. In particular, it would be designed to take advantage of the fact that a Fresnel diffraction pattern is ultrasensitive to distance. The two versions would differ in the following respects: In version 1, the focus of the telescope would be in the Fresnel region, and the telescope would have a small depth of focus. As a consequence, the Fresnel pattern would be imaged directly onto the photodetector array; in version 2, a multielement lens module would displace the Fresnel region from the vicinity of the pinhole to the vicinity of the optical receiver. As the distance to be measured varied, the location of the receiver relative to the displaced Fresnel-diffraction region would vary, thereby causing the Fresnel diffraction pattern on the focal plane to vary. The multielement lens module would also correct for aberrations. The processing of the digitized Fresnel diffraction pattern in the computer might be accelerated by using only parts of the pattern or even only one small part - the central pixel. As the distance from the pinhole increased, the central pixel would rapidly cycle between maximum and minimum light intensity. This in itself would not be sufficient to uniquely determine the distance. However, by varying the size of the pinhole or the wavelength of the laser, one could obtain a second cycle of variation of intensity that, in conjunction with the first cycle, could enable a unique determination of distance. Alternatively, for a single wavelength and a single pinhole size, it should suffice to consider the data from only two different key pixels in the Fresnel pattern.
Developing accurate molecular mechanics force fields for conjugated molecular systems.
Do, Hainam; Troisi, Alessandro
2015-10-14
A rapid method to parameterize the intramolecular component of classical force fields for complex conjugated molecules is proposed. The method is based on a procedure of force matching with a reference electronic structure calculation. It is particularly suitable for those applications where molecular dynamics simulations are used to generate structures that are therefore analysed by electronic structure methods, because it is possible to build force fields that are consistent with electronic structure calculations that follow classical simulations. Such applications are commonly encountered in organic electronics, spectroscopy of complex systems and photobiology (e.g. photosynthetic systems). We illustrate the method by parameterizing the force fields of a molecule used in molecular semiconductors (2,2-dicyanovinyl-capped S,N-heteropentacene or DCV-SN5), a polymeric semiconductor (thieno[3,2-b]thiophene-diketopyrrolopyrrole TT-DPP) and a chromophore embedded in a protein environment (15,16-dihydrobiliverdin or DBV) where several hundreds of parameters need to be optimized in parallel.
Accurate telemonitoring of Parkinson's disease diagnosis using robust inference system.
Mandal, Indrajit; Sairam, N
2013-05-01
This work presents more precise computational methods for improving the diagnosis of Parkinson's disease based on the detection of dysphonia. New methods are presented for enhanced evaluation and recognize Parkinson's disease affected patients at early stage. Analysis is performed with significant level of error tolerance rate and established our results with corrected T-test. Here new ensembles and other machine learning methods consisting of multinomial logistic regression classifier with Haar wavelets transformation as projection filter that outperform logistic regression is used. Finally a novel and reliable inference system is presented for early recognition of people affected by this disease and presents a new measure of the severity of the disease. Feature selection method is based on Support Vector Machines and ranker search method. Performance analysis of each model is compared to the existing methods and examines the main advancements and concludes with propitious results. Reliable methods are proposed for treating Parkinson's disease that includes sparse multinomial logistic regression, Bayesian network, Support Vector Machines, Artificial Neural Networks, Boosting methods and their ensembles. The study aim at improving the quality of Parkinson's disease treatment by tracking them and reinforce the viability of cost effective, regular and precise telemonitoring application.
Polymer Matrix Composites for Propulsion Systems
NASA Technical Reports Server (NTRS)
Nettles, Alan T.
2003-01-01
The Access-to-Space study identified the requirement for lightweight structures to achieve orbit with a single-stage vehicle. Thus a task was undertaken to examine the use of polymer matrix composites for propulsion components. It was determined that the effort of this task would be to extend previous efforts with polymer matrix composite feedlines and demonstrate the feasibility of manufacturing large diameter feedlines with a complex shape and integral flanges, (i.e. all one piece with a 90 deg bend), and assess their performance under a cryogenic atmosphere.
Improved Ecosystem Predictions of the California Current System via Accurate Light Calculations
2011-09-30
System via Accurate Light Calculations Curtis D. Mobley Sequoia Scientific, Inc. 2700 Richards Road, Suite 107 Bellevue, WA 98005 phone: 425...incorporate extremely fast but accurate light calculations into coupled physical-biological-optical ocean ecosystem models as used for operational three...dimensional ecosystem predictions. Improvements in light calculations lead to improvements in predictions of chlorophyll concentrations and other
NASA Astrophysics Data System (ADS)
Yan, Wang-Ji; Katafygiotis, Lambros S.
2016-10-01
The problem of stochastic system identification utilizing response measurements only is considered in this paper. A negative log-likelihood function utilized to determine the posterior most probable parameters and their associated uncertainties is formulated by incorporating transmissibility matrix concept, random matrix theory and Bayes’ theorem. A numerically iterative coupled method involving the optimization of the parameters in groups is proposed so as to reduce the dimension of the numerical optimization problem involved. The initial guess for the parameters to be optimized is also properly estimated through asymptotic analysis. One novel feature of the proposed method is to avoid repeated time-consuming evaluation of the determinant and inverse of the covariance matrix during optimization due to exploring the statistical properties of the trace of Wishart matrix. The proposed method requires no information about the model of the external input. The theory described in this work is illustrated with synthetic data and field data measured from a laboratory model installed with wireless sensors.
Matrix Interconnection System for Aircraft Wiring
1975-07-01
Aircraft Wiring, ECOM-0102-1, Feb. I973 mmmmMam "" \\:.-JLl.- *"’" " ’^nf--’--^7 -w .mm-m .mm BSU! (2) obtain due to the classified nature of the...steps 2 and 3 of MODE 2 to operate the intercoms. 2’ TTpe gtpp 1 of MODE 3 tn opprnte the compass. Do not rotate the SITS, MODE 10 This test is to be...TABLE II TABLE III TABLE IV MODES OF OPERATION MATRIX OH- GA HELICOPTER EMC EVALUATION OH- GA HELICOPTER EMC EVALUATION TEST SUMMARY GROUND TEST
Accurate Shim-Coil Design and Magnet-Field Profiling by a Power-Minimization-Matrix Method
NASA Astrophysics Data System (ADS)
Hoult, D. I.; Deslauriers, R.
The design of a single correction coil that annuls, with minimal power consumption, the field inhomogeneity associated with a specific magnet is described. The design strategy used is also shown to be advantageous for the production of high-accuracy, power-efficient shim coils, "drift-free" shims (i.e., no slow mainfield drift following a change of shim current), and high-homogeneity "shielded" magnets. Starting with a description of field inhomogeneity in a spherical-harmonic basis set, the cylindrical-surface current-density function needed to annul inhomogeneity is calculated, with minimization of electrical power dissipation, by a simple matrix formulation. The inclusion of design constraints, such as the annulment of mutual inductance between zonal shims and the magnet, is highlighted and production of the current-density function with both wire and cut sheet is briefly discussed. Insights are presented as to why the method, unlike some, gives a smooth current-density function lacking spurious high-frequency ripples, and experimental and numerical tests are reported that reveal the efficacy of the computational procedures.
Information Theory Density Matrix for a Simple Quantum System.
ERIC Educational Resources Information Center
Titus, William J.
1979-01-01
Derives the density matrix that best describes, according to information theory, a one-dimensional single particle quantum system when the only information available is the values for the linear and quadratic position-momentum moments. (Author/GA)
Filler/ Polycarbosilane Systems as CMC Matrix Precursors
NASA Technical Reports Server (NTRS)
Hurwitz, Frances I.
1998-01-01
Pyrolytic conversion of polymeric precursors to ceramics is accompanied by loss of volatiles and large volume changes. Infiltration of a low viscosity polymer into a fiber preform will fill small spaces within fiber tows by capillary forces, but create large matrix cracks within large, intertow areas. One approach to minimizing shrinkage and reducing the number of required infiltration cycles is to use particulate fillers. In this study, Starfire allylhydridopolycarbosilane (AHPCS) was blended with a silicon carbide powder, with and without dispersant, using shear mixing. The polymer and polymer/particle interactions were characterized using nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis and rheometry. Polymer/particulate slurries and suspensions were used to infiltrate a figidized preform of an eight ply five harness satin CG Nicalon fiber having a dual layer BN/SiC interface coating, and the resulting composites characterized by optical and scanning electron microscopy.
Advanced fiber/matrix material systems
NASA Technical Reports Server (NTRS)
Hartness, J. Timothy
1991-01-01
Work completed in Phase 1 of the NASA Advanced Composite Technology program is discussed. Two towpreg forms (commingled yarns and fused powder towpregs) are being characterized under the program. These towpregs will be used to evaluate textile fabrication technologies for advanced aircraft composite structures. The unique characteristic of both of these material forms is that both fiber and matrix resin are handled in a single operation such as weaving, braiding, or fiber placement. The evaluation of both commingled and fused powder towpreg is described. Various polymer materials are considered for both subsonic and supersonic applications. Polymers initially being evaluated include thermoplastic polyimides such as Larc-TPI and New-TPI, thermoplastics such as PEEK and PEKEKK as well as some toughened crosslinked polyimides. Preliminary mechanical properties as well as tow handling are evaluated.
Santos, Hugo M; Reboiro-Jato, Miguel; Glez-Peña, Daniel; Nunes-Miranda, J D; Fdez-Riverola, Florentino; Carvallo, R; Capelo, J L
2010-09-15
The decision peptide-driven tool implements a software application for assisting the user in a protocol for accurate protein quantification based on the following steps: (1) protein separation through gel electrophoresis; (2) in-gel protein digestion; (3) direct and inverse (18)O-labeling and (4) matrix assisted laser desorption ionization time of flight mass spectrometry, MALDI analysis. The DPD software compares the MALDI results of the direct and inverse (18)O-labeling experiments and quickly identifies those peptides with paralleled loses in different sets of a typical proteomic workflow. Those peptides are used for subsequent accurate protein quantification. The interpretation of the MALDI data from direct and inverse labeling experiments is time-consuming requiring a significant amount of time to do all comparisons manually. The DPD software shortens and simplifies the searching of the peptides that must be used for quantification from a week to just some minutes. To do so, it takes as input several MALDI spectra and aids the researcher in an automatic mode (i) to compare data from direct and inverse (18)O-labeling experiments, calculating the corresponding ratios to determine those peptides with paralleled losses throughout different sets of experiments; and (ii) allow to use those peptides as internal standards for subsequent accurate protein quantification using (18)O-labeling. In this work the DPD software is presented and explained with the quantification of protein carbonic anhydrase.
Stationary density matrix of a pumped polariton system.
Vera, Carlos Andrés; Cabo, Alejandro; González, Augusto
2009-03-27
The density matrix rho of a model polariton system is obtained numerically from a master equation which takes account of pumping and losses. In the stationary limit, the coherences between eigenstates of the Hamiltonian are 3 orders of magnitude smaller than the occupations, meaning that the stationary density matrix is approximately diagonal in the energy representation. A weakly distorted grand canonical Gibbs distribution fits well the occupations.
Dong, H; Shum, P; Yan, M; Zhou, J Q; Ning, G X; Gong, Y D; Wu, C Q
2006-06-12
A generalized Mueller matrix method (GMMM) is proposed to measure the polarization mode dispersion (PMD) in an optical fiber system with polarization-dependent loss or gain (PDL/G). This algorithm is based on the polar decomposition of a 4X4 matrix which corresponds to a Lorentz transformation. Compared to the generalized Poincaré sphere method, the GMMM can measure PMD accurately with a relatively larger frequency step, and the obtained PMD data has very low noise level.
Open quantum systems and random matrix theory
Mulhall, Declan
2014-10-15
A simple model for open quantum systems is analyzed with RMT. The system is coupled to the continuum in a minimal way. In this paper we see the effect of opening the system on the level statistics, in particular the level spacing, width distribution and Δ{sub 3}(L) statistic are examined as a function of the strength of this coupling. The usual super-radiant state is observed, and it is seen that as it is formed, the level spacing and Δ{sub 3}(L) statistic exhibit the signatures of missed levels.
Open quantum systems and random matrix theory
NASA Astrophysics Data System (ADS)
Mulhall, Declan
2014-10-01
A simple model for open quantum systems is analyzed with RMT. The system is coupled to the continuum in a minimal way. In this paper we see the effect of opening the system on the level statistics, in particular the level spacing, width distribution and Δ3(L) statistic are examined as a function of the strength of this coupling. The usual super-radiant state is observed, and it is seen that as it is formed, the level spacing and Δ3(L) statistic exhibit the signatures of missed levels.
RF system calibration for global Q matrix determination
Padormo, Francesco; Beqiri, Arian; Malik, Shaihan J.; Hajnal, Joseph V.
2016-01-01
The use of multiple transmission channels (known as Parallel Transmission, or PTx) provides increased control of the MRI signal formation process. This extra flexibility comes at a cost of uncertainty of the power deposited in the patient under examination: the electric fields produced by each transmitter can interfere in such a way to lead to excessively high heating. Although it is not possible to determine local heating, the global Q matrix (which allows the whole-body Specific Absorption Rate (SAR) to be known for any PTx pulse) can be measured in-situ by monitoring the power incident upon and reflected by each transmit element during transmission. Recent observations have shown that measured global Q matrices can be corrupted by losses between the coil array and location of power measurement. In this work we demonstrate that these losses can be accounted for, allowing accurate global Q matrix measurement independent of the location of the power measurement devices. PMID:26747407
High temperature metal matrix composites for future aerospace systems
NASA Technical Reports Server (NTRS)
Stephens, Joseph R.
1988-01-01
Research was conducted on metal matrix composites and intermetallic matrix composites to understand their behavior under anticipated future operating conditions envisioned for aerospace power and propulsion systems of the 21st century. Extremes in environmental conditions, high temperature, long operating lives, and cyclic conditions dictate that the test evaluations not only include laboratory testing, but simulated flight conditions. The various processing techniques employed to fabricate composites are discussed along with the basic research underway to understand the behavior of high temperature composites, and the relationship of this research to future aerospace systems.
High temperature metal matrix composites for future aerospace systems
NASA Technical Reports Server (NTRS)
Stephens, Joseph R.
1987-01-01
Research was conducted on metal matrix composites and intermetallic matrix composites to understand their behavior under anticipated future operating conditions envisioned for aerospace power and propulsion systems of the 21st century. Extremes in environmental conditions, high temperature, long operating lives, and cyclic conditions dictate that the test evaluations not only include laboratory testing, but simulated flight conditions. The various processing techniques employed to fabricate composites are discussed along with the basic research underway to understand the behavior of high temperature composites, and the relationship of this research to future aerospace systems.
Conditional random matrix ensembles and the stability of dynamical systems
NASA Astrophysics Data System (ADS)
Kirk, Paul; Rolando, Delphine M. Y.; MacLean, Adam L.; Stumpf, Michael P. H.
2015-08-01
Random matrix theory (RMT) has found applications throughout physics and applied mathematics, in subject areas as diverse as communications networks, population dynamics, neuroscience, and models of the banking system. Many of these analyses exploit elegant analytical results, particularly the circular law and its extensions. In order to apply these results, assumptions must be made about the distribution of matrix elements. Here we demonstrate that the choice of matrix distribution is crucial. In particular, adopting an unrealistic matrix distribution for the sake of analytical tractability is liable to lead to misleading conclusions. We focus on the application of RMT to the long-standing, and at times fractious, ‘diversity-stability debate’, which is concerned with establishing whether large complex systems are likely to be stable. Early work (and subsequent elaborations) brought RMT to bear on the debate by modelling the entries of a system’s Jacobian matrix as independent and identically distributed (i.i.d.) random variables. These analyses were successful in yielding general results that were not tied to any specific system, but relied upon a restrictive i.i.d. assumption. Other studies took an opposing approach, seeking to elucidate general principles of stability through the analysis of specific systems. Here we develop a statistical framework that reconciles these two contrasting approaches. We use a range of illustrative dynamical systems examples to demonstrate that: (i) stability probability cannot be summarily deduced from any single property of the system (e.g. its diversity); and (ii) our assessment of stability depends on adequately capturing the details of the systems analysed. Failing to condition on the structure of dynamical systems will skew our analysis and can, even for very small systems, result in an unnecessarily pessimistic diagnosis of their stability.
ERIC Educational Resources Information Center
Pobocik, Tamara J.
2013-01-01
The use of technology and electronic medical records in healthcare has exponentially increased. This quantitative research project used a pretest/posttest design, and reviewed how an educational electronic documentation system helped nursing students to identify the accurate related to statement of the nursing diagnosis for the patient in the case…
NASA Astrophysics Data System (ADS)
Kretkowski, Maciej; Jablonski, Ryszard; Shimodaira, Yoshifumi
Acquisition of accurate colors is important in the modern era of widespread exchange of electronic multimedia. The variety of device-dependent color spaces causes troubles with accurate color reproduction. In this paper we present the outlines of accomplished digital camera system with device-independent output formed from tristimulus XYZ values. The outstanding accuracy and fidelity of acquired color is achieved in our system by employing an embedded color calibration system based on emissive device generating reference calibration colors with user-defined spectral distribution and chromaticity coordinates. The system was tested by calibrating the camera using 24 reference colors spectrally reproduced from 24 color patches of the Macbeth Chart. The average color difference (CIEDE2000) has been found to be ΔE =0.83, which is an outstanding result compared to commercially available digital cameras.
Accurate GPS Time-Linked data Acquisition System (ATLAS II) user's manual.
Jones, Perry L.; Zayas, Jose R.; Ortiz-Moyet, Juan
2004-02-01
The Accurate Time-Linked data Acquisition System (ATLAS II) is a small, lightweight, time-synchronized, robust data acquisition system that is capable of acquiring simultaneous long-term time-series data from both a wind turbine rotor and ground-based instrumentation. This document is a user's manual for the ATLAS II hardware and software. It describes the hardware and software components of ATLAS II, and explains how to install and execute the software.
Aluminum/Silicon Carbide Matrix Material for Targeting System
2006-07-21
most common MMC is cast aluminum reinforced with various amounts of silicon carbide . LMMFC is currently machining very high precision components for...targeting systems from cast aluminum/ silicon carbide (AISiC) matrix material (with a very high SiC content) and are experiencing difficulty achieving the
Aluminum / Silicon Carbide Matrix Material Machining for Targeting Systems
2006-07-21
most common (MMC) is cast aluminum reinforced with various amounts of silicon carbide . (LMMFC) is currently machining very high precision components for...targeting systems made from cast aluminum/ silicon carbide (AISiC) matrix material (with a very high SiC content) and is experiencing difficulty
Ghasemi, K; Khanmohammadi, M; Saligheh Rad, H
2016-02-01
Hydrogen magnetic resonance spectroscopy ((1) H-MRS) is a non-invasive technique which provides a 'frequency-signal intensity' spectrum of biochemical compounds of tissues in the body. Although this method is currently used in human brain studies, accurate classification of in-vivo (1) H-MRS is a challenging task in the diagnosis of brain tumors. Problems such as overlapping metabolite peaks, incomplete information on background component and low signal-to-noise ratio disturb classification results of this spectroscopic method. This study presents an alternative approach to the soft independent modeling of class analogy (SIMCA) technique, using non-negative matrix factorization (NMF) for dimensionality reduction. In the adopted strategy, the performance of SIMCA was improved by application of a robust algorithm for classification in the presence of noisy measurements. Total of 219 spectra from two databases were taken by water-suppressed short echo-time (1) H-MRS, acquired from different subjects with different stages of glial brain tumors (Grade II (26 cases), grade III (24 cases), grade IV (41 cases), as well as 25 healthy cases). The SIMCA was performed using two approaches: (i) principal component analysis (PCA) and (ii) non-negative matrix factorization (NMF), as a modified approach. Square prediction error was considered to assess the class membership of the external validation set. Finally, several figures of merit such as the correct classification rate (CCR), sensitivity and specificity were calculated. Results of SIMCA based on NMF showed significant improvement in percentage of correctly classified samples, 91.4% versus 83.5% for PCA-based model in an independent test set.
A path-oriented matrix-based knowledge representation system
NASA Technical Reports Server (NTRS)
Feyock, Stefan; Karamouzis, Stamos T.
1993-01-01
Experience has shown that designing a good representation is often the key to turning hard problems into simple ones. Most AI (Artificial Intelligence) search/representation techniques are oriented toward an infinite domain of objects and arbitrary relations among them. In reality much of what needs to be represented in AI can be expressed using a finite domain and unary or binary predicates. Well-known vector- and matrix-based representations can efficiently represent finite domains and unary/binary predicates, and allow effective extraction of path information by generalized transitive closure/path matrix computations. In order to avoid space limitations a set of abstract sparse matrix data types was developed along with a set of operations on them. This representation forms the basis of an intelligent information system for representing and manipulating relational data.
NASA Technical Reports Server (NTRS)
Oliver, B. M.; Gower, J. F. R.
1977-01-01
A data acquisition system using a Litton LTN-51 inertial navigation unit (INU) was tested and used for aircraft track recovery and for location and tracking from the air of targets at sea. The characteristic position drift of the INU is compensated for by sighting landmarks of accurately known position at discrete time intervals using a visual sighting system in the transparent nose of the Beechcraft 18 aircraft used. For an aircraft altitude of about 300 m, theoretical and experimental tests indicate that calculated aircraft and/or target positions obtained from the interpolated INU drift curve will be accurate to within 10 m for landmarks spaced approximately every 15 minutes in time. For applications in coastal oceanography, such as surface current mapping by tracking artificial targets, the system allows a broad area to be covered without use of high altitude photography and its attendant needs for large targets and clear weather.
Managing information systems: an ethical framework and information needs matrix.
Caputo, R K
1991-01-01
This paper urged administrators in human services to attend to values and ethics in the design and implementation of automated information systems. Toward this end, it presented an ethical framework reasserting the primacy of clients as citizens and encouraging the development of client-driven information systems. Finally, the paper presented the rationale for and two examples of an Information Needs Matrix to assist administrators in their deliberations about allocating discretionary resources among functional units within organizations.
Alanio, A; Beretti, J-L; Dauphin, B; Mellado, E; Quesne, G; Lacroix, C; Amara, A; Berche, P; Nassif, X; Bougnoux, M-E
2011-05-01
New Aspergillus species have recently been described with the use of multilocus sequencing in refractory cases of invasive aspergillosis. The classical phenotypic identification methods routinely used in clinical laboratories failed to identify them adequately. Some of these Aspergillus species have specific patterns of susceptibility to antifungal agents, and misidentification may lead to inappropriate therapy. We developed a matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS)-based strategy to adequately identify Aspergillus species to the species level. A database including the reference spectra of 28 clinically relevant species from seven Aspergillus sections (five common and 23 unusual species) was engineered. The profiles of young and mature colonies were analysed for each reference strain, and species-specific spectral fingerprints were identified. The performance of the database was then tested on 124 clinical and 16 environmental isolates previously characterized by partial sequencing of the β-tubulin and calmodulin genes. One hundred and thirty-eight isolates of 140 (98.6%) were correctly identified. Two atypical isolates could not be identified, but no isolate was misidentified (specificity: 100%). The database, including species-specific spectral fingerprints of young and mature colonies of the reference strains, allowed identification regardless of the maturity of the clinical isolate. These results indicate that MALDI-TOF MS is a powerful tool for rapid and accurate identification of both common and unusual species of Aspergillus. It can give better results than morphological identification in clinical laboratories.
Development of Star Tracker System for Accurate Estimation of Spacecraft Attitude
2009-12-01
TRACKER SYSTEM FOR ACCURATE ESTIMATION OF SPACECRAFT ATTITUDE by Jack A. Tappe December 2009 Thesis Co-Advisors: Jae Jun Kim Brij N... Brij N. Agrawal Co-Advisor Dr. Knox T. Millsaps Chairman, Department of Mechanical and Astronautical Engineering iv THIS PAGE...much with my studies here. I would like to especially thank Professors Barry Leonard, Brij Agrawal, Grand Master Shin, and Comrade Oleg Yakimenko
A fast and accurate image-based measuring system for isotropic reflection materials
NASA Astrophysics Data System (ADS)
Kim, Duck Bong; Kim, Kang Yeon; Park, Kang Su; Seo, Myoung Kook; Lee, Kwan H.
2008-08-01
We present a novel image-based BRDF (Bidirectional Reflectance Distribution Function) measurement system for materials that have isotropic reflectance properties. Our proposed system is fast due to simple set up and automated operations. It also provides a wide angular coverage and noise reduction capability so that it achieves accuracy that is needed for computer graphics applications. We test the uniformity and constancy of the light source and the reciprocity of the measurement system. We perform a photometric calibration of HDR (High Dynamic Range) camera to recover an accurate radiance map from each HDR image. We verify our proposed system by comparing it with a previous imagebased BRDF measurement system. We demonstrate the efficiency and accuracy of our proposed system by generating photorealistic images of the measured BRDF data that include glossy blue, green plastics, gold coated metal and gold metallic paints.
Highly accurate and fast optical penetration-based silkworm gender separation system
NASA Astrophysics Data System (ADS)
Kamtongdee, Chakkrit; Sumriddetchkajorn, Sarun; Chanhorm, Sataporn
2015-07-01
Based on our research work in the last five years, this paper highlights our innovative optical sensing system that can identify and separate silkworm gender highly suitable for sericulture industry. The key idea relies on our proposed optical penetration concepts and once combined with simple image processing operations leads to high accuracy in identifying of silkworm gender. Inside the system, there are electronic and mechanical parts that assist in controlling the overall system operation, processing the optical signal, and separating the female from male silkworm pupae. With current system performance, we achieve a very highly accurate more than 95% in identifying gender of silkworm pupae with an average system operational speed of 30 silkworm pupae/minute. Three of our systems are already in operation at Thailand's Queen Sirikit Sericulture Centers.
Barallobre-Barreiro, Javier; Lynch, Marc; Yin, Xiaoke; Mayr, Manuel
2016-01-01
Systems biology approaches including proteomics are becoming more widely used in cardiovascular research. In this review article, we focus on the application of proteomics to the cardiac extracellular matrix (ECM). ECM remodelling is a hallmark of many cardiovascular diseases. Proteomic techniques using mass spectrometry (MS) provide a platform for the comprehensive analysis of ECM proteins without a priori assumptions. Proteomics overcomes various constraints inherent to conventional antibody detection. On the other hand, studies that use whole tissue lysates for proteomic analysis mask the identification of the less abundant ECM constituents. In this review, we first discuss decellularization-based methods that enrich for ECM proteins in cardiac tissue, and how targeted MS allows for accurate protein quantification. The second part of the review will focus on post-translational modifications including hydroxylation and glycosylation and on the release of matrix fragments with biological activity (matrikines), all of which can be interrogated by proteomic techniques. PMID:27635058
Roles and regulation of the matrix metalloproteinase system in parturition.
Geng, Junnan; Huang, Cong; Jiang, Siwen
2016-04-01
Significant tissue destruction, repair, and remodeling are involved in parturition, which involves fetal membrane rupture, cervical ripening, and uterine contraction and its subsequent involution. Extracellular matrix degradation and remodeling by proteolytic enzymes, such as matrix metalloproteinases (MMPs), are required for the final steps of parturition. MMPs participate in physiological degradation and remodeling through their proteolytic activities on specific substrates, and are balanced by the action of their inhibitors. Disruption to this balance can result in pathological stress that ends with preterm or post-term birth or pre-eclampsia. In this review, we examine the roles and regulation of the MMP system in physiological and pathological labor, and propose a model that illustrates the mechanisms by which the MMP system contributes to these processes.
Multiple-frequency continuous wave ultrasonic system for accurate distance measurement
NASA Astrophysics Data System (ADS)
Huang, C. F.; Young, M. S.; Li, Y. C.
1999-02-01
A highly accurate multiple-frequency continuous wave ultrasonic range-measuring system for use in air is described. The proposed system uses a method heretofore applied to radio frequency distance measurement but not to air-based ultrasonic systems. The method presented here is based upon the comparative phase shifts generated by three continuous ultrasonic waves of different but closely spaced frequencies. In the test embodiment to confirm concept feasibility, two low cost 40 kHz ultrasonic transducers are set face to face and used to transmit and receive ultrasound. Individual frequencies are transmitted serially, each generating its own phase shift. For any given frequency, the transmitter/receiver distance modulates the phase shift between the transmitted and received signals. Comparison of the phase shifts allows a highly accurate evaluation of target distance. A single-chip microcomputer-based multiple-frequency continuous wave generator and phase detector was designed to record and compute the phase shift information and the resulting distance, which is then sent to either a LCD or a PC. The PC is necessary only for calibration of the system, which can be run independently after calibration. Experiments were conducted to test the performance of the whole system. Experimentally, ranging accuracy was found to be within ±0.05 mm, with a range of over 1.5 m. The main advantages of this ultrasonic range measurement system are high resolution, low cost, narrow bandwidth requirements, and ease of implementation.
Enzyme system comprising an enzyme bonded in a porous matrix
Ackerman, Eric [Richland, WA; Liu, Jun [West Richland, WA
2010-12-07
A protein system is described in which a protein is bound within a matrix material that has pores that are sized to achieve excellent properties such as: activity, protein density, and stability. In a preferred embodiment, the pore sizes range from 50 to 400 .ANG.. One protein that has demonstrated surprisingly good results in this system is OPH. This protein is known to degrade organophosphorus compounds such as are found in chemical weapons and pesticides. Novel methods of forming the protein system and methods of making OPH are also described.
MARS-3 matrix radiometric system for RATAN-600
NASA Astrophysics Data System (ADS)
Berlin, A. B.; Parijskij, Yu. N.; Nizhelskij, N. A.; Mingaliev, M. G.; Tsybulev, P. G.; Kratov, D. V.; Udovitskiy, R. Yu.; Smirnov, V. V.; Pylypenko, O. M.
2012-07-01
The MARS-3 third-generation matrix radiometric system has been developed, manufactured, and is currently being used in observations within the framework of the "Cosmological Gene" program. The system is based on new hardware components and consists of 16 independent radiometers (32 horns with a step of 20 mm). Each pair of horns is connected to the input of an amplifier unit via a square-loop modulator. The parameters of each radiometer are: central frequency, 30.0 GHz; bandwidth, 5GHz; average noise temperature of the system, 250 K; and a sensitivity of about 5 mK for τ = RC = 1 s.
Interactive display system having a matrix optical detector
Veligdan, James T.; DeSanto, Leonard
2007-01-23
A display system includes a waveguide optical panel having an inlet face and an opposite outlet face. An image beam is projected across the inlet face laterally and transversely for display on the outlet face. An optical detector including a matrix of detector elements is optically aligned with the inlet face for detecting a corresponding lateral and transverse position of an inbound light spot on the outlet face.
NASA Technical Reports Server (NTRS)
Arnaiz, H. H.
1975-01-01
As part of a NASA program to evaluate current methods of predicting the performance of large, supersonic airplanes, the drag of the XB-70 airplane was measured accurately in flight at Mach numbers from 0.75 to 2.5. This paper describes the techniques used to determine engine net thrust and the drag forces charged to the propulsion system that were required for the in-flight drag measurements. The accuracy of the measurements and the application of the measurement techniques to aircraft with different propulsion systems are discussed. Examples of results obtained for the XB-70 airplane are presented.
Villalobos, Rafael; Ganem, Adriana; Cordero, Salomón; Vidales, Ana Maria; Domínguez, Armando
2005-07-01
The main objective of this work is to study the drug release behavior from inert matrix systems by using computer simulation. This study allowed us to propose a new statistical method to evaluate the drug percolation threshold as a function of the exposed surface area of the device. The matrix system was simulated as a simple cubic lattice. The sites of the lattice were randomly occupied at various drug-excipient ratios. By simulating a diffusive process, the drug was delivered from the matrix system. The obtained release profiles were fitted to two different models: near the excipient percolation threshold, the square root of the time was well fitted, whereas close to (but above) the drug percolation threshold, the power law described accurately the release data. A relationship between the initial drug load and the amount of drug trapped inside the matrix system at infinite time was found. This relationship was conveniently described by an error function. Percolation thresholds in the matrix systems were determined from the latter relationship by using a nonlinear regression method. The assessment of percolation thresholds depends on the exposed surface area of the matrix systems. Moreover, estimated percolation thresholds were in agreement with the predicted values stated in the percolation theory.
NASA Technical Reports Server (NTRS)
Lee, Harry
1994-01-01
A highly accurate transmission line fault locator based on the traveling-wave principle was developed and successfully operated within B.C. Hydro. A transmission line fault produces a fast-risetime traveling wave at the fault point which propagates along the transmission line. This fault locator system consists of traveling wave detectors located at key substations which detect and time tag the leading edge of the fault-generated traveling wave as if passes through. A master station gathers the time-tagged information from the remote detectors and determines the location of the fault. Precise time is a key element to the success of this system. This fault locator system derives its timing from the Global Positioning System (GPS) satellites. System tests confirmed the accuracy of locating faults to within the design objective of +/-300 meters.
Reduction Effect of EMI in Parallel Matrix Converter Systems
NASA Astrophysics Data System (ADS)
Ayano, Hideki; Inaba, Hiromi; Ogasawara, Satoshi
This paper proposes a large-scale matrix converter system which connects two main circuits in parallel and in which the carriers operating each main circuit have a phase difference of 180 degrees. A matrix converter needs an LC filter, not only because it acts as a conventional filter which reduces high frequency ripples caused by the converter switching, but also because the capacitor of the LC filter acts as a virtual voltage source. Therefore, this filter must be connected at the input side. The proposed system uses a miniaturized LC filter because the harmonics of the current flowing into the LC filter contain only the even number harmonics of the carrier and the cut-off frequency of the LC filter can be raised. For example, when the cut-off frequency is doubled, the inductor or the capacitor of the LC filter can be reduced to 1/4. The principle of raising the filter current's frequency is verified theoretically using simulations. Furthermore, in the proposed system, the distortion of the output voltages become less than with a conventional single matrix converter, and the common mode voltage and the common mode current, which cause electromagnetic interference (EMI), can also be decreased.
Accurate Vehicle Location System Using RFID, an Internet of Things Approach.
Prinsloo, Jaco; Malekian, Reza
2016-06-04
Modern infrastructure, such as dense urban areas and underground tunnels, can effectively block all GPS signals, which implies that effective position triangulation will not be achieved. The main problem that is addressed in this project is the design and implementation of an accurate vehicle location system using radio-frequency identification (RFID) technology in combination with GPS and the Global system for Mobile communication (GSM) technology, in order to provide a solution to the limitation discussed above. In essence, autonomous vehicle tracking will be facilitated with the use of RFID technology where GPS signals are non-existent. The design of the system and the results are reflected in this paper. An extensive literature study was done on the field known as the Internet of Things, as well as various topics that covered the integration of independent technology in order to address a specific challenge. The proposed system is then designed and implemented. An RFID transponder was successfully designed and a read range of approximately 31 cm was obtained in the low frequency communication range (125 kHz to 134 kHz). The proposed system was designed, implemented, and field tested and it was found that a vehicle could be accurately located and tracked. It is also found that the antenna size of both the RFID reader unit and RFID transponder plays a critical role in the maximum communication range that can be achieved.
Accurate Vehicle Location System Using RFID, an Internet of Things Approach
Prinsloo, Jaco; Malekian, Reza
2016-01-01
Modern infrastructure, such as dense urban areas and underground tunnels, can effectively block all GPS signals, which implies that effective position triangulation will not be achieved. The main problem that is addressed in this project is the design and implementation of an accurate vehicle location system using radio-frequency identification (RFID) technology in combination with GPS and the Global system for Mobile communication (GSM) technology, in order to provide a solution to the limitation discussed above. In essence, autonomous vehicle tracking will be facilitated with the use of RFID technology where GPS signals are non-existent. The design of the system and the results are reflected in this paper. An extensive literature study was done on the field known as the Internet of Things, as well as various topics that covered the integration of independent technology in order to address a specific challenge. The proposed system is then designed and implemented. An RFID transponder was successfully designed and a read range of approximately 31 cm was obtained in the low frequency communication range (125 kHz to 134 kHz). The proposed system was designed, implemented, and field tested and it was found that a vehicle could be accurately located and tracked. It is also found that the antenna size of both the RFID reader unit and RFID transponder plays a critical role in the maximum communication range that can be achieved. PMID:27271638
Ortuño, J E; Kontaxakis, G; Rubio, J L; Guerra, P; Santos, A
2010-04-07
A fully 3D iterative image reconstruction algorithm has been developed for high-resolution PET cameras composed of pixelated scintillator crystal arrays and rotating planar detectors, based on the ordered subsets approach. The associated system matrix is precalculated with Monte Carlo methods that incorporate physical effects not included in analytical models, such as positron range effects and interaction of the incident gammas with the scintillator material. Custom Monte Carlo methodologies have been developed and optimized for modelling of system matrices for fast iterative image reconstruction adapted to specific scanner geometries, without redundant calculations. According to the methodology proposed here, only one-eighth of the voxels within two central transaxial slices need to be modelled in detail. The rest of the system matrix elements can be obtained with the aid of axial symmetries and redundancies, as well as in-plane symmetries within transaxial slices. Sparse matrix techniques for the non-zero system matrix elements are employed, allowing for fast execution of the image reconstruction process. This 3D image reconstruction scheme has been compared in terms of image quality to a 2D fast implementation of the OSEM algorithm combined with Fourier rebinning approaches. This work confirms the superiority of fully 3D OSEM in terms of spatial resolution, contrast recovery and noise reduction as compared to conventional 2D approaches based on rebinning schemes. At the same time it demonstrates that fully 3D methodologies can be efficiently applied to the image reconstruction problem for high-resolution rotational PET cameras by applying accurate pre-calculated system models and taking advantage of the system's symmetries.
Mazziotti, David A
2016-10-07
A central challenge of physics is the computation of strongly correlated quantum systems. The past ten years have witnessed the development and application of the variational calculation of the two-electron reduced density matrix (2-RDM) without the wave function. In this Letter we present an orders-of-magnitude improvement in the accuracy of 2-RDM calculations without an increase in their computational cost. The advance is based on a low-rank, dual formulation of an important constraint on the 2-RDM, the T2 condition. Calculations are presented for metallic chains and a cadmium-selenide dimer. The low-scaling T2 condition will have significant applications in atomic and molecular, condensed-matter, and nuclear physics.
NASA Astrophysics Data System (ADS)
Mazziotti, David A.
2016-10-01
A central challenge of physics is the computation of strongly correlated quantum systems. The past ten years have witnessed the development and application of the variational calculation of the two-electron reduced density matrix (2-RDM) without the wave function. In this Letter we present an orders-of-magnitude improvement in the accuracy of 2-RDM calculations without an increase in their computational cost. The advance is based on a low-rank, dual formulation of an important constraint on the 2-RDM, the T 2 condition. Calculations are presented for metallic chains and a cadmium-selenide dimer. The low-scaling T 2 condition will have significant applications in atomic and molecular, condensed-matter, and nuclear physics.
Prometheus: Scalable and Accurate Emulation of Task-Based Applications on Many-Core Systems.
Kestor, Gokcen; Gioiosa, Roberto; Chavarría-Miranda, Daniel
2015-03-01
Modeling the performance of non-deterministic parallel applications on future many-core systems requires the development of novel simulation and emulation techniques and tools. We present “Prometheus”, a fast, accurate and modular emulation framework for task-based applications. By raising the level of abstraction and focusing on runtime synchronization, Prometheus can accurately predict applications’ performance on very large many-core systems. We validate our emulation framework against two real platforms (AMD Interlagos and Intel MIC) and report error rates generally below 4%. We, then, evaluate Prometheus’ performance and scalability: our results show that Prometheus can emulate a task-based application on a system with 512K cores in 11.5 hours. We present two test cases that show how Prometheus can be used to study the performance and behavior of systems that present some of the characteristics expected from exascale supercomputer nodes, such as active power management and processors with a high number of cores but reduced cache per core.
TOKUMITSU, YUKIO; TAMESA, TAKAO; MATSUKUMA, SATOSHI; HASHIMOTO, NORIAKI; MAEDA, YOSHINARI; TOKUHISA, YOSHIHIRO; SAKAMOTO, KAZUHIKO; UENO, TOMIO; HAZAMA, SHOICHI; OGIHARA, HIROYUKI; FUJITA, YUSUKE; HAMAMOTO, YOSHIHIKO; OKA, MASAAKI; IIZUKA, NORIO
2015-01-01
The aim of this study was to develop an accurate predictive system for prognosis of hepatocellular carcinoma (HCC) patients after hepatectomy. We pooled data of clinicopathological features of 234 HCC patients who underwent curative hepatectomy. On the basis of the pooled data, we established a simple predictive staging system (PS score) scored by the mathematical product of tumor number and size, and degree of liver function. We compared the prognostic abilities of the PS score (score 0–3) with those of six well-known clinical staging systems. Then, we found that there were significant differences (P<0.05) in both disease-free survival (DFS) and overall survival (OS) between patients with different PS scores (PS score 0 vs. 1; PS score 1 vs. 2), and there was a significant difference in DFS, but not OS, between patients with PS score 2 and those with PS score 3. Moreover, the PS score had smaller values of the Akaike information criterion for both DFS and OS than any of the six well-known clinical staging systems. These results suggest that the PS score serves as a simple, accurate predictor for the prognosis of HCC patients after hepatectomy. PMID:25524574
Development and Clinical Evaluation of MatrixMANDIBLE Subcondylar Plates System (Synthes).
Cortelazzi, Roberto; Altacera, Mario; Turco, Monica; Antonicelli, Viviana; De Benedittis, Michele
2015-06-01
In this article, authors report the different steps of development and clinical validation of MatrixMANDIBLE Subcondylar Plates (Synthes, Soletta, Switzerland), a specialized osteosynthesis system developed by Synthes during the past 4 years. Between 2009 and 2013, a total of 62 patients were treated for subcondylar and condylar neck fractures via a preauricular or retromandibular/transparotid approach. The MatrixMANDIBLE Subcondylar Plates System consists of a Trapezoidal Plate, a three-dimensional (3D) 4-hole 1.0-mm plate for smaller fracture areas, the Lambda Plate, a 7-hole 1.0-mm linear plate which mimics the two miniplates technique, and the Strut Plate, a 3D 1.0-mm plate with great versatility of employment. All devices satisfy the principles of a functionally stable osteosynthesis as stated by Champy et al. None of the plates broke and no macroscopic condylar displacement was noted on radiological follow-up. Clinical and functional parameters assessed at 6 months postoperative (mandibular range of motion, pain, dental occlusion) were almost restored. MatrixMANDIBLE Subcondylar Plates System (Synthes) has proved to provide sufficient mechanical stiffness and anatomically accurate fracture reduction to avoid major postoperative drawbacks of subcondylar and condylar neck fractures.
Sparse matrix methods research using the CSM testbed software system
NASA Technical Reports Server (NTRS)
Chu, Eleanor; George, J. Alan
1989-01-01
Research is described on sparse matrix techniques for the Computational Structural Mechanics (CSM) Testbed. The primary objective was to compare the performance of state-of-the-art techniques for solving sparse systems with those that are currently available in the CSM Testbed. Thus, one of the first tasks was to become familiar with the structure of the testbed, and to install some or all of the SPARSPAK package in the testbed. A suite of subroutines to extract from the data base the relevant structural and numerical information about the matrix equations was written, and all the demonstration problems distributed with the testbed were successfully solved. These codes were documented, and performance studies comparing the SPARSPAK technology to the methods currently in the testbed were completed. In addition, some preliminary studies were done comparing some recently developed out-of-core techniques with the performance of the testbed processor INV.
NASA Astrophysics Data System (ADS)
El-Diasty, M.
2014-11-01
An accurate heading solution is required for many applications and it can be achieved by high grade (high cost) gyroscopes (gyros) which may not be suitable for such applications. Micro-Electro Mechanical Systems-based (MEMS) is an emerging technology, which has the potential of providing heading solution using a low cost MEMS-based gyro. However, MEMS-gyro-based heading solution drifts significantly over time. The heading solution can also be estimated using MEMS-based magnetometer by measuring the horizontal components of the Earth magnetic field. The MEMS-magnetometer-based heading solution does not drift over time, but are contaminated by high level of noise and may be disturbed by the presence of magnetic field sources such as metal objects. This paper proposed an accurate heading estimation procedure based on the integration of MEMS-based gyro and magnetometer measurements that correct gyro and magnetometer measurements where gyro angular rates of changes are estimated using magnetometer measurements and then integrated with the measured gyro angular rates of changes with a robust filter to estimate the heading. The proposed integration solution is implemented using two data sets; one was conducted in static mode without magnetic disturbances and the second was conducted in kinematic mode with magnetic disturbances. The results showed that the proposed integrated heading solution provides accurate, smoothed and undisturbed solution when compared with magnetometerbased and gyro-based heading solutions.
NASA Technical Reports Server (NTRS)
Alter, Stephen J.; Brauckmann, Gregory J.; Kleb, Bil; Streett, Craig L; Glass, Christopher E.; Schuster, David M.
2015-01-01
Using the Fully Unstructured Three-Dimensional (FUN3D) computational fluid dynamics code, an unsteady, time-accurate flow field about a Space Launch System configuration was simulated at a transonic wind tunnel condition (Mach = 0.9). Delayed detached eddy simulation combined with Reynolds Averaged Naiver-Stokes and a Spallart-Almaras turbulence model were employed for the simulation. Second order accurate time evolution scheme was used to simulate the flow field, with a minimum of 0.2 seconds of simulated time to as much as 1.4 seconds. Data was collected at 480 pressure taps at locations, 139 of which matched a 3% wind tunnel model, tested in the Transonic Dynamic Tunnel (TDT) facility at NASA Langley Research Center. Comparisons between computation and experiment showed agreement within 5% in terms of location for peak RMS levels, and 20% for frequency and magnitude of power spectral densities. Grid resolution and time step sensitivity studies were performed to identify methods for improved accuracy comparisons to wind tunnel data. With limited computational resources, accurate trends for reduced vibratory loads on the vehicle were observed. Exploratory methods such as determining minimized computed errors based on CFL number and sub-iterations, as well as evaluating frequency content of the unsteady pressures and evaluation of oscillatory shock structures were used in this study to enhance computational efficiency and solution accuracy. These techniques enabled development of a set of best practices, for the evaluation of future flight vehicle designs in terms of vibratory loads.
Localized motion in random matrix decomposition of complex financial systems
NASA Astrophysics Data System (ADS)
Jiang, Xiong-Fei; Zheng, Bo; Ren, Fei; Qiu, Tian
2017-04-01
With the random matrix theory, we decompose the multi-dimensional time series of complex financial systems into a set of orthogonal eigenmode functions, which are classified into the market mode, sector mode, and random mode. In particular, the localized motion generated by the business sectors, plays an important role in financial systems. Both the business sectors and their impact on the stock market are identified from the localized motion. We clarify that the localized motion induces different characteristics of the time correlations for the stock-market index and individual stocks. With a variation of a two-factor model, we reproduce the return-volatility correlations of the eigenmodes.
Identification and calibration of the interaction matrix parameters for AO and MCAO systems
NASA Astrophysics Data System (ADS)
Neichel, Benoit; Parisot, Amelie; Petit, Cyril; Fusco, Thierry; Rigaut, François
2012-07-01
New tomographic Adaptive Optics (AO) concepts require a good knowledge of the system geometry and characteristics. These parameters are used to feed the tomographic reconstructors. In this paper we present a method to precisely identify the parameters required to construct an accurate synthetic set of models such as inuence functions, mis-registrations, directions of analysis or altitude of the DMs. The method is based on a multiparameter t of the interaction matrix. This identication method nds also its application in high contrast AO systems, such as SPHERE : in that case it is used as a diagnostic tool in order to precisely realign the system. The method has been tested and successfully implemented on HOMER, SPHERE and GeMS. Experimental results for these three systems are presented.
A ceramic matrix composite thermal protection system for hypersonic vehicles
NASA Technical Reports Server (NTRS)
Riccitiello, Salvatore R.; Love, Wendell L.; Pitts, William C.
1993-01-01
The next generation of hypersonic vehicles (NASP, SSTO) that require reusable thermal protection systems will experience acreage surface temperatures in excess of 1100 C. More important, they will experience a more severe physical environment than the Space Shuttle due to non-pristine launching and landing conditions. As a result, maintenance, inspection, and replacement factors must be more thoroughly incorporated into the design of the TPS. To meet these requirements, an advanced thermal protection system was conceived, designated 'TOPHAT'. This system consists of a toughened outer ceramic matrix composite (CMC) attached to a rigid reusable surface insulator (RSI) which is directly bonded to the surface. The objective of this effort was to evaluate this concept in an aeroconvective environment, to determine the effect of impacts to the CMC material, and to compare the results with existing thermal protection systems.
NASA Astrophysics Data System (ADS)
Kase, Wataru
In this paper, it will be clear the structure of the Iterative Learning Control (ILC) based on the inverse system. Moore-Penrose pseudo-inverse of a Toeplitz matrix will be investigated to analyze the learning gain matrix and will be derived the cascade controller transfer function matrix. From these investigations, the critical points of ILC based on the gradient will be issued.
NASA Astrophysics Data System (ADS)
He, Wantao; Li, Zhongwei; Zhong, Kai; Shi, Yusheng; Zhao, Can; Cheng, Xu
2014-11-01
Fast and precise 3D inspection system is in great demand in modern manufacturing processes. At present, the available sensors have their own pros and cons, and hardly exist an omnipotent sensor to handle the complex inspection task in an accurate and effective way. The prevailing solution is integrating multiple sensors and taking advantages of their strengths. For obtaining a holistic 3D profile, the data from different sensors should be registrated into a coherent coordinate system. However, some complex shape objects own thin wall feather such as blades, the ICP registration method would become unstable. Therefore, it is very important to calibrate the extrinsic parameters of each sensor in the integrated measurement system. This paper proposed an accurate and automatic extrinsic parameter calibration method for blade measurement system integrated by different optical sensors. In this system, fringe projection sensor (FPS) and conoscopic holography sensor (CHS) is integrated into a multi-axis motion platform, and the sensors can be optimally move to any desired position at the object's surface. In order to simple the calibration process, a special calibration artifact is designed according to the characteristics of the two sensors. An automatic registration procedure based on correlation and segmentation is used to realize the artifact datasets obtaining by FPS and CHS rough alignment without any manual operation and data pro-processing, and then the Generalized Gauss-Markoff model is used to estimate the optimization transformation parameters. The experiments show the measurement result of a blade, where several sampled patches are merged into one point cloud, and it verifies the performance of the proposed method.
Sakai, C; Takeda, S N; Daimon, H
2013-07-01
We have developed the new in situ electrical-conductivity measurement system which can be operated in ultrahigh vacuum (UHV) with accurate temperature measurement down to 20 K. This system is mainly composed of a new sample-holder fixing mechanism, a new movable conductivity-measurement mechanism, a cryostat, and two receptors for sample- and four-probe holders. Sample-holder is pushed strongly against the receptor, which is connected to a cryostat, by using this new sample-holder fixing mechanism to obtain high thermal conductivity. Test pieces on the sample-holders have been cooled down to about 20 K using this fixing mechanism, although they were cooled down to only about 60 K without this mechanism. Four probes are able to be touched to a sample surface using this new movable conductivity-measurement mechanism for measuring electrical conductivity after making film on substrates or obtaining clean surfaces by cleavage, flashing, and so on. Accurate temperature measurement is possible since the sample can be transferred with a thermocouple and∕or diode being attached directly to the sample. A single crystal of Bi-based copper oxide high-Tc superconductor (HTSC) was cleaved in UHV to obtain clean surface, and its superconducting critical temperature has been successfully measured in situ. The importance of in situ measurement of resistance in UHV was demonstrated for this HTSC before and after cesium (Cs) adsorption on its surface. The Tc onset increase and the Tc offset decrease by Cs adsorption were observed.
Development and calibration of an accurate 6-degree-of-freedom measurement system with total station
NASA Astrophysics Data System (ADS)
Gao, Yang; Lin, Jiarui; Yang, Linghui; Zhu, Jigui
2016-12-01
To meet the demand of high-accuracy, long-range and portable use in large-scale metrology for pose measurement, this paper develops a 6-degree-of-freedom (6-DOF) measurement system based on total station by utilizing its advantages of long range and relative high accuracy. The cooperative target sensor, which is mainly composed of a pinhole prism, an industrial lens, a camera and a biaxial inclinometer, is designed to be portable in use. Subsequently, a precise mathematical model is proposed from the input variables observed by total station, imaging system and inclinometer to the output six pose variables. The model must be calibrated in two levels: the intrinsic parameters of imaging system, and the rotation matrix between coordinate systems of the camera and the inclinometer. Then corresponding approaches are presented. For the first level, we introduce a precise two-axis rotary table as a calibration reference. And for the second level, we propose a calibration method by varying the pose of a rigid body with the target sensor and a reference prism on it. Finally, through simulations and various experiments, the feasibilities of the measurement model and calibration methods are validated, and the measurement accuracy of the system is evaluated.
On the ``Matrix Approach'' to Interacting Particle Systems
NASA Astrophysics Data System (ADS)
de Sanctis, L.; Isopi, M.
2004-04-01
Derrida et al. and Schütz and Stinchcombe gave algebraic formulas for the correlation functions of the partially asymmetric simple exclusion process. Here we give a fairly general recipe of how to get these formulas and extend them to the whole time evolution (starting from the generator of the process), for a certain class of interacting systems. We then analyze the algebraic relations obtained to show that the matrix approach does not work with some models such as the voter and the contact processes.
Distributed fiber sensing system with wide frequency response and accurate location
NASA Astrophysics Data System (ADS)
Shi, Yi; Feng, Hao; Zeng, Zhoumo
2016-02-01
A distributed fiber sensing system merging Mach-Zehnder interferometer and phase-sensitive optical time domain reflectometer (Φ-OTDR) is demonstrated for vibration measurement, which requires wide frequency response and accurate location. Two narrow line-width lasers with delicately different wavelengths are used to constitute the interferometer and reflectometer respectively. A narrow band Fiber Bragg Grating is responsible for separating the two wavelengths. In addition, heterodyne detection is applied to maintain the signal to noise rate of the locating signal. Experiment results show that the novel system has a wide frequency from 1 Hz to 50 MHz, limited by the sample frequency of data acquisition card, and a spatial resolution of 20 m, according to 200 ns pulse width, along 2.5 km fiber link.
NASA Astrophysics Data System (ADS)
Sharma, Sandeep; Alavi, Ali
2015-09-01
We propose a multireference linearized coupled cluster theory using matrix product states (MPSs-LCC) which provides remarkably accurate ground-state energies, at a computational cost that has the same scaling as multireference configuration interaction singles and doubles, for a wide variety of electronic Hamiltonians. These range from first-row dimers at equilibrium and stretched geometries to highly multireference systems such as the chromium dimer and lattice models such as periodic two-dimensional 1-band and 3-band Hubbard models. The MPS-LCC theory shows a speed up of several orders of magnitude over the usual Density Matrix Renormalization Group (DMRG) algorithm while delivering energies in excellent agreement with converged DMRG calculations. Also, in all the benchmark calculations presented here, MPS-LCC outperformed the commonly used multi-reference quantum chemistry methods in some cases giving energies in excess of an order of magnitude more accurate. As a size-extensive method that can treat large active spaces, MPS-LCC opens up the use of multireference quantum chemical techniques in strongly correlated ab initio Hamiltonians, including two- and three-dimensional solids.
Sharma, Sandeep; Alavi, Ali
2015-09-14
We propose a multireference linearized coupled cluster theory using matrix product states (MPSs-LCC) which provides remarkably accurate ground-state energies, at a computational cost that has the same scaling as multireference configuration interaction singles and doubles, for a wide variety of electronic Hamiltonians. These range from first-row dimers at equilibrium and stretched geometries to highly multireference systems such as the chromium dimer and lattice models such as periodic two-dimensional 1-band and 3-band Hubbard models. The MPS-LCC theory shows a speed up of several orders of magnitude over the usual Density Matrix Renormalization Group (DMRG) algorithm while delivering energies in excellent agreement with converged DMRG calculations. Also, in all the benchmark calculations presented here, MPS-LCC outperformed the commonly used multi-reference quantum chemistry methods in some cases giving energies in excess of an order of magnitude more accurate. As a size-extensive method that can treat large active spaces, MPS-LCC opens up the use of multireference quantum chemical techniques in strongly correlated ab initio Hamiltonians, including two- and three-dimensional solids.
A Low-Cost, Accurate, and High-Precision Fluid Dispensing System for Microscale Application.
Das, Champak; Wang, Guochun; Nguyen, Chien
2017-04-01
We present here the development of a low-cost, accurate, and precise fluid dispensing system. It can be used with peristaltic or any other pump to improve the flow characteristics. The dispensing system has a range of 1 to 100 µL with accuracy of ~99.5% and standard deviation at ~150 nL over the entire range. The system developed does not depend on the accuracy or precision of the driving pump; therefore, any positive displacement pump can be used to get similar accuracy and precision, which gives an opportunity to reduce the cost of the system. The dispensing system does not require periodic calibration and can also be miniaturized for microfluidic application. Although primarily designed for aqueous liquid, it can be extended for different nonconductive liquids as well with modifications. The unit is further used for near real-time measurement of lactate from microdialysate. The individual components can easily be made disposable or sterilized for use in biomedical applications.
Accurate calibration of a stereo-vision system in image-guided radiotherapy
Liu Dezhi; Li Shidong
2006-11-15
Image-guided radiotherapy using a three-dimensional (3D) camera as the on-board surface imaging system requires precise and accurate registration of the 3D surface images in the treatment machine coordinate system. Two simple calibration methods, an analytical solution as three-point matching and a least-squares estimation method as multipoint registration, were introduced to correlate the stereo-vision surface imaging frame with the machine coordinate system. Both types of calibrations utilized 3D surface images of a calibration template placed on the top of the treatment couch. Image transformational parameters were derived from corresponding 3D marked points on the surface images to their given coordinates in the treatment room coordinate system. Our experimental results demonstrated that both methods had provided the desired calibration accuracy of 0.5 mm. The multipoint registration method is more robust particularly for noisy 3D surface images. Both calibration methods have been used as our weekly QA tools for a 3D image-guided radiotherapy system.
Lindner, Claudia; Wang, Ching-Wei; Huang, Cheng-Ta; Li, Chung-Hsing; Chang, Sheng-Wei; Cootes, Tim F.
2016-01-01
Cephalometric tracing is a standard analysis tool for orthodontic diagnosis and treatment planning. The aim of this study was to develop and validate a fully automatic landmark annotation (FALA) system for finding cephalometric landmarks in lateral cephalograms and its application to the classification of skeletal malformations. Digital cephalograms of 400 subjects (age range: 7–76 years) were available. All cephalograms had been manually traced by two experienced orthodontists with 19 cephalometric landmarks, and eight clinical parameters had been calculated for each subject. A FALA system to locate the 19 landmarks in lateral cephalograms was developed. The system was evaluated via comparison to the manual tracings, and the automatically located landmarks were used for classification of the clinical parameters. The system achieved an average point-to-point error of 1.2 mm, and 84.7% of landmarks were located within the clinically accepted precision range of 2.0 mm. The automatic landmark localisation performance was within the inter-observer variability between two clinical experts. The automatic classification achieved an average classification accuracy of 83.4% which was comparable to an experienced orthodontist. The FALA system rapidly and accurately locates and analyses cephalometric landmarks in lateral cephalograms, and has the potential to significantly improve the clinical work flow in orthodontic treatment. PMID:27645567
NASA Astrophysics Data System (ADS)
Sun, Jianwei; Remsing, Richard C.; Zhang, Yubo; Sun, Zhaoru; Ruzsinszky, Adrienn; Peng, Haowei; Yang, Zenghui; Paul, Arpita; Waghmare, Umesh; Wu, Xifan; Klein, Michael L.; Perdew, John P.
2016-09-01
One atom or molecule binds to another through various types of bond, the strengths of which range from several meV to several eV. Although some computational methods can provide accurate descriptions of all bond types, those methods are not efficient enough for many studies (for example, large systems, ab initio molecular dynamics and high-throughput searches for functional materials). Here, we show that the recently developed non-empirical strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) within the density functional theory framework predicts accurate geometries and energies of diversely bonded molecules and materials (including covalent, metallic, ionic, hydrogen and van der Waals bonds). This represents a significant improvement at comparable efficiency over its predecessors, the GGAs that currently dominate materials computation. Often, SCAN matches or improves on the accuracy of a computationally expensive hybrid functional, at almost-GGA cost. SCAN is therefore expected to have a broad impact on chemistry and materials science.
The variational two-electron reduced-density-matrix method for extended systems
NASA Astrophysics Data System (ADS)
Rubin, Nicholas C.
In this thesis we develop the variational two-electron reduced-density-matrix method for extended systems. Extended systems are represented in two ways: i) lattice models describing the dominant valence electronic structure with periodic boundaries to account for their extended nature and ii) a crystalline-orbital basis built from atomic orbitals using the generalization of molecular orbital theory to polymers. The first part of this thesis (Ch. 3--4) examines the performance of the variational 2-RDM method on lattice systems with tunable electron correlation. The first of these systems is the classic Hubbard model with linear and ladder lattice topologies. Because electron correlation functions, such as charge- and spin-ordering, are linear functions of the 2-RDM, the difference in electronic structure between one- and quasi-one-dimensional systems is accurately characterized. The second model contains only two-body interactions and is unique among typical spin models in that it does not have a mean-field reference wave function. The ground state wave functions from all Hamiltonians in the model have the same 1-electron reduced density matrix; consequently, one-electron theories are largely inapplicable. The superconducting eta-pairing ground states make the model a unique tool for demonstrating the necessary N-representability in highly correlated environments. The second part of this thesis (Ch. 5--6) develops a formalism for modeling materials by solving the full Schrodinger equation. Crystalline-orbital Hartree-Fock provides a set of orbitals and integral tensors for the variational 2-RDM method. We demonstrate that time-reversal symmetry, which is implicitly included in position space electronic structure calculations, must be explicitly included as an N-representability constraint on the 2-RDM when using a momentum space basis. The necessity of these equality constraints is demonstrated by the accurate recovery of the binding energy of two polymers and the
Structural stability augmentation system design using BODEDIRECT: A quick and accurate approach
NASA Technical Reports Server (NTRS)
Goslin, T. J.; Ho, J. K.
1989-01-01
A methodology is presented for a modal suppression control law design using flight test data instead of mathematical models to obtain the required gain and phase information about the flexible airplane. This approach is referred to as BODEDIRECT. The purpose of the BODEDIRECT program is to provide a method of analyzing the modal phase relationships measured directly from the airplane. These measurements can be achieved with a frequency sweep at the control surface input while measuring the outputs of interest. The measured Bode-models can be used directly for analysis in the frequency domain, and for control law design. Besides providing a more accurate representation for the system inputs and outputs of interest, this method is quick and relatively inexpensive. To date, the BODEDIRECT program has been tested and verified for computational integrity. Its capabilities include calculation of series, parallel and loop closure connections between Bode-model representations. System PSD, together with gain and phase margins of stability may be calculated for successive loop closures of multi-input/multi-output systems. Current plans include extensive flight testing to obtain a Bode-model representation of a commercial aircraft for design of a structural stability augmentation system.
Takahashi, F; Endo, A
2007-01-01
A system utilising radiation transport codes has been developed to derive accurate dose distributions in a human body for radiological accidents. A suitable model is quite essential for a numerical analysis. Therefore, two tools were developed to setup a 'problem-dependent' input file, defining a radiation source and an exposed person to simulate the radiation transport in an accident with the Monte Carlo calculation codes-MCNP and MCNPX. Necessary resources are defined by a dialogue method with a generally used personal computer for both the tools. The tools prepare human body and source models described in the input file format of the employed Monte Carlo codes. The tools were validated for dose assessment in comparison with a past criticality accident and a hypothesized exposure.
Fast and spectrally accurate Ewald summation for 2-periodic electrostatic systems
NASA Astrophysics Data System (ADS)
Lindbo, Dag; Tornberg, Anna-Karin
2012-04-01
A new method for Ewald summation in planar/slablike geometry, i.e., systems where periodicity applies in two dimensions and the last dimension is "free" (2P), is presented. We employ a spectral representation in terms of both Fourier series and integrals. This allows us to concisely derive both the 2P Ewald sum and a fast particle mesh Ewald (PME)-type method suitable for large-scale computations. The primary results are: (i) close and illuminating connections between the 2P problem and the standard Ewald sum and associated fast methods for full periodicity; (ii) a fast, O(N log N), and spectrally accurate PME-type method for the 2P k-space Ewald sum that uses vastly less memory than traditional PME methods; (iii) errors that decouple, such that parameter selection is simplified. We give analytical and numerical results to support this.
Grebner, Christoph; Becker, Johannes; Weber, Daniel; Bellinger, Daniel; Tafipolski, Maxim; Brückner, Charlotte; Engels, Bernd
2014-09-15
The presented program package, Conformational Analysis and Search Tool (CAST) allows the accurate treatment of large and flexible (macro) molecular systems. For the determination of thermally accessible minima CAST offers the newly developed TabuSearch algorithm, but algorithms such as Monte Carlo (MC), MC with minimization, and molecular dynamics are implemented as well. For the determination of reaction paths, CAST provides the PathOpt, the Nudge Elastic band, and the umbrella sampling approach. Access to free energies is possible through the free energy perturbation approach. Along with a number of standard force fields, a newly developed symmetry-adapted perturbation theory-based force field is included. Semiempirical computations are possible through DFTB+ and MOPAC interfaces. For calculations based on density functional theory, a Message Passing Interface (MPI) interface to the Graphics Processing Unit (GPU)-accelerated TeraChem program is available. The program is available on request.
Development of Metal Matrix Composites for NASA'S Advanced Propulsion Systems
NASA Technical Reports Server (NTRS)
Lee, Jonathan A.
2000-01-01
The state-of-the-art development of several aluminum and copper based Metal Matrix Composites (MMC) for NASA's advanced propulsion systems will be presented. The presentation's goal is to provide an overview of NASA-Marshall Space Flight Center's planned and on-going activities in MMC for advanced liquid rocket engines such as the X-33 vehicle's Aerospike and X-34 Fastrac engine. The focus will be on lightweight and environmental compatibility with oxygen and hydrogen of key MMC materials, within each NASA's new propulsion application, that will provide a high payoff for NASA's reusable launch vehicle systems and space access vehicles. Advanced MMC processing techniques such as plasma spray, centrifugal casting, pressure infiltration casting will be discussed. Development of a novel 3D printing method for low cost production of composite preform, and functional gradient MMC to enhanced rocket engine's dimensional stability will be presented.
Wong, Sharon; Back, Michael; Tan, Poh Wee; Lee, Khai Mun; Baggarley, Shaun; Lu, Jaide Jay
2012-07-01
Skin doses have been an important factor in the dose prescription for breast radiotherapy. Recent advances in radiotherapy treatment techniques, such as intensity-modulated radiation therapy (IMRT) and new treatment schemes such as hypofractionated breast therapy have made the precise determination of the surface dose necessary. Detailed information of the dose at various depths of the skin is also critical in designing new treatment strategies. The purpose of this work was to assess the accuracy of surface dose calculation by a clinically used treatment planning system and those measured by thermoluminescence dosimeters (TLDs) in a customized chest wall phantom. This study involved the construction of a chest wall phantom for skin dose assessment. Seven TLDs were distributed throughout each right chest wall phantom to give adequate representation of measured radiation doses. Point doses from the CMS Xio Registered-Sign treatment planning system (TPS) were calculated for each relevant TLD positions and results correlated. There were no significant difference between measured absorbed dose by TLD and calculated doses by the TPS (p > 0.05 (1-tailed). Dose accuracy of up to 2.21% was found. The deviations from the calculated absorbed doses were overall larger (3.4%) when wedges and bolus were used. 3D radiotherapy TPS is a useful and accurate tool to assess the accuracy of surface dose. Our studies have shown that radiation treatment accuracy expressed as a comparison between calculated doses (by TPS) and measured doses (by TLD dosimetry) can be accurately predicted for tangential treatment of the chest wall after mastectomy.
Highly accurate moving object detection in variable bit rate video-based traffic monitoring systems.
Huang, Shih-Chia; Chen, Bo-Hao
2013-12-01
Automated motion detection, which segments moving objects from video streams, is the key technology of intelligent transportation systems for traffic management. Traffic surveillance systems use video communication over real-world networks with limited bandwidth, which frequently suffers because of either network congestion or unstable bandwidth. Evidence supporting these problems abounds in publications about wireless video communication. Thus, to effectively perform the arduous task of motion detection over a network with unstable bandwidth, a process by which bit-rate is allocated to match the available network bandwidth is necessitated. This process is accomplished by the rate control scheme. This paper presents a new motion detection approach that is based on the cerebellar-model-articulation-controller (CMAC) through artificial neural networks to completely and accurately detect moving objects in both high and low bit-rate video streams. The proposed approach is consisted of a probabilistic background generation (PBG) module and a moving object detection (MOD) module. To ensure that the properties of variable bit-rate video streams are accommodated, the proposed PBG module effectively produces a probabilistic background model through an unsupervised learning process over variable bit-rate video streams. Next, the MOD module, which is based on the CMAC network, completely and accurately detects moving objects in both low and high bit-rate video streams by implementing two procedures: 1) a block selection procedure and 2) an object detection procedure. The detection results show that our proposed approach is capable of performing with higher efficacy when compared with the results produced by other state-of-the-art approaches in variable bit-rate video streams over real-world limited bandwidth networks. Both qualitative and quantitative evaluations support this claim; for instance, the proposed approach achieves Similarity and F1 accuracy rates that are 76
A Three Dimensional Parallel Time Accurate Turbopump Simulation Procedure Using Overset Grid Systems
NASA Technical Reports Server (NTRS)
Kiris, Cetin; Chan, William; Kwak, Dochan
2001-01-01
The objective of the current effort is to provide a computational framework for design and analysis of the entire fuel supply system of a liquid rocket engine, including high-fidelity unsteady turbopump flow analysis. This capability is needed to support the design of pump sub-systems for advanced space transportation vehicles that are likely to involve liquid propulsion systems. To date, computational tools for design/analysis of turbopump flows are based on relatively lower fidelity methods. An unsteady, three-dimensional viscous flow analysis tool involving stationary and rotational components for the entire turbopump assembly has not been available for real-world engineering applications. The present effort provides developers with information such as transient flow phenomena at start up, and non-uniform inflows, and will eventually impact on system vibration and structures. In the proposed paper, the progress toward the capability of complete simulation of the turbo-pump for a liquid rocket engine is reported. The Space Shuttle Main Engine (SSME) turbo-pump is used as a test case for evaluation of the hybrid MPI/Open-MP and MLP versions of the INS3D code. CAD to solution auto-scripting capability is being developed for turbopump applications. The relative motion of the grid systems for the rotor-stator interaction was obtained using overset grid techniques. Unsteady computations for the SSME turbo-pump, which contains 114 zones with 34.5 million grid points, are carried out on Origin 3000 systems at NASA Ames Research Center. Results from these time-accurate simulations with moving boundary capability will be presented along with the performance of parallel versions of the code.
A Three-Dimensional Parallel Time-Accurate Turbopump Simulation Procedure Using Overset Grid System
NASA Technical Reports Server (NTRS)
Kiris, Cetin; Chan, William; Kwak, Dochan
2002-01-01
The objective of the current effort is to provide a computational framework for design and analysis of the entire fuel supply system of a liquid rocket engine, including high-fidelity unsteady turbopump flow analysis. This capability is needed to support the design of pump sub-systems for advanced space transportation vehicles that are likely to involve liquid propulsion systems. To date, computational tools for design/analysis of turbopump flows are based on relatively lower fidelity methods. An unsteady, three-dimensional viscous flow analysis tool involving stationary and rotational components for the entire turbopump assembly has not been available for real-world engineering applications. The present effort provides developers with information such as transient flow phenomena at start up, and nonuniform inflows, and will eventually impact on system vibration and structures. In the proposed paper, the progress toward the capability of complete simulation of the turbo-pump for a liquid rocket engine is reported. The Space Shuttle Main Engine (SSME) turbo-pump is used as a test case for evaluation of the hybrid MPI/Open-MP and MLP versions of the INS3D code. CAD to solution auto-scripting capability is being developed for turbopump applications. The relative motion of the grid systems for the rotor-stator interaction was obtained using overset grid techniques. Unsteady computations for the SSME turbo-pump, which contains 114 zones with 34.5 million grid points, are carried out on Origin 3000 systems at NASA Ames Research Center. Results from these time-accurate simulations with moving boundary capability are presented along with the performance of parallel versions of the code.
Zhang, Shengzhi; Yu, Shuai; Liu, Chaojun; Liu, Sheng
2016-06-01
Tracking the position of pedestrian is urgently demanded when the most commonly used GPS (Global Position System) is unavailable. Benefited from the small size, low-power consumption, and relatively high reliability, micro-electro-mechanical system sensors are well suited for GPS-denied indoor pedestrian heading estimation. In this paper, a real-time miniature orientation determination system (MODS) was developed for indoor heading and trajectory tracking based on a novel dual-linear Kalman filter. The proposed filter precludes the impact of geomagnetic distortions on pitch and roll that the heading is subjected to. A robust calibration approach was designed to improve the accuracy of sensors measurements based on a unified sensor model. Online tests were performed on the MODS with an improved turntable. The results demonstrate that the average RMSE (root-mean-square error) of heading estimation is less than 1°. Indoor heading experiments were carried out with the MODS mounted on the shoe of pedestrian. Besides, we integrated the existing MODS into an indoor pedestrian dead reckoning application as an example of its utility in realistic actions. A human attitude-based walking model was developed to calculate the walking distance. Test results indicate that mean percentage error of indoor trajectory tracking achieves 2% of the total walking distance. This paper provides a feasible alternative for accurate indoor heading and trajectory tracking.
Majda, Andrew J; Grote, Marcus J
2007-01-23
Many contemporary problems in science involve making predictions based on partial observation of extremely complicated spatially extended systems with many degrees of freedom and physical instabilities on both large and small scales. Various new ensemble filtering strategies have been developed recently for these applications, and new mathematical issues arise. Here, explicit off-line test criteria for stable accurate discrete filtering are developed for use in the above context and mimic the classical stability analysis for finite difference schemes. First, constant coefficient partial differential equations, which are randomly forced and damped to mimic mesh scale energy spectra in the above problems are developed as off-line filtering test problems. Then mathematical analysis is used to show that under natural suitable hypothesis the time filtering algorithms for general finite difference discrete approximations to an sxs partial differential equation system with suitable observations decompose into much simpler independent s-dimensional filtering problems for each spatial wave number separately; in other test problems, such block diagonal models rigorously provide upper and lower bounds on the filtering algorithm. In this fashion, elementary off-line filtering criteria can be developed for complex spatially extended systems. The theory is illustrated for time filters by using both unstable and implicit difference scheme approximations to the stochastically forced heat equation where the combined effects of filter stability and model error are analyzed through the simpler off-line criteria.
A novel sulfur mustard (HD) vapor inhalation exposure system for accurate inhaled dose delivery
Perry, Mark R.; Benson, Eric M.; Kohne, Jonathon W.; Plahovinsak, Jennifer L.; Babin, Michael C.; Platoff, Gennady E.; Yeung, David T.
2014-01-01
Introduction A custom designed HD exposure system was used to deliver controlled inhaled doses to an animal model through an endotracheal tube. Methods Target HD vapor challenges were generated by a temperature controlled bubbler/aerosol trap, while concentration was monitored near real-time by gas chromatography. Animal breathing parameters were monitored real-time by an in-line pneumotach, pressure transducer, and Buxco pulmonary analysis computer/software. For each exposure, the challenge atmosphere was allowed to stabilize at the desired concentration while the anesthetized animal was provided humidity controlled clean air. Once the target concentration was achieved and stable, a portion of the challenge atmosphere was drawn past the endotracheal tube, where the animal inhaled the exposure ad libitum. During the exposure, HD vapor concentration and animal weight were used to calculate the needed inhaled volume to achieve the target inhaled dose (μg/kg). The exposures were halted when the inhaled volume was achieved. Results The exposure system successfully controlled HD concentrations from 22.2 to 278 mg/m3 and accurately delivered inhaled doses between 49.3 and 1120 μg/kg with actual administered doses being within 4% of the target level. Discussion This exposure system administers specific HD inhaled doses to evaluate physiological effects and for evaluation of potential medical countermeasure treatments. PMID:25291290
NASA Astrophysics Data System (ADS)
Zhang, Shengzhi; Yu, Shuai; Liu, Chaojun; Liu, Sheng
2016-06-01
Tracking the position of pedestrian is urgently demanded when the most commonly used GPS (Global Position System) is unavailable. Benefited from the small size, low-power consumption, and relatively high reliability, micro-electro-mechanical system sensors are well suited for GPS-denied indoor pedestrian heading estimation. In this paper, a real-time miniature orientation determination system (MODS) was developed for indoor heading and trajectory tracking based on a novel dual-linear Kalman filter. The proposed filter precludes the impact of geomagnetic distortions on pitch and roll that the heading is subjected to. A robust calibration approach was designed to improve the accuracy of sensors measurements based on a unified sensor model. Online tests were performed on the MODS with an improved turntable. The results demonstrate that the average RMSE (root-mean-square error) of heading estimation is less than 1°. Indoor heading experiments were carried out with the MODS mounted on the shoe of pedestrian. Besides, we integrated the existing MODS into an indoor pedestrian dead reckoning application as an example of its utility in realistic actions. A human attitude-based walking model was developed to calculate the walking distance. Test results indicate that mean percentage error of indoor trajectory tracking achieves 2% of the total walking distance. This paper provides a feasible alternative for accurate indoor heading and trajectory tracking.
Quantum Phase Transitions in Conventional Matrix Product Systems
NASA Astrophysics Data System (ADS)
Zhu, Jing-Min; Huang, Fei; Chang, Yan
2017-02-01
For matrix product states(MPSs) of one-dimensional spin-1/2 chains, we investigate a new kind of conventional quantum phase transition(QPT). We find that the system has two different ferromagnetic phases; on the line of the two ferromagnetic phases coexisting equally, the system in the thermodynamic limit is in an isolated mediate-coupling state described by a paramagnetic state and is in the same state as the renormalization group fixed point state, the expectation values of the physical quantities are discontinuous, and any two spin blocks of the system have the same geometry quantum discord(GQD) within the range of open interval (0,0.25) and the same classical correlation(CC) within the range of open interval (0,0.75) compared to any phase having no any kind of correlation. We not only realize the control of QPTs but also realize the control of quantum correlation of quantum many-body systems on the critical line by adjusting the environment parameters, which may have potential application in quantum information fields and is helpful to comprehensively and deeply understand the quantum correlation, and the organization and structure of quantum correlation especially for long-range quantum correlation of quantum many-body systems.
Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc; Binnekamp, Dirk
2015-03-15
Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora{sup ®} Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.
Development of Metal Matrix Composites for NASA's Advanced Propulsion Systems
NASA Technical Reports Server (NTRS)
Lee, J.; Elam, S.
2001-01-01
The state-of-the-art development of several Metal Matrix Composites (MMC) for NASA's advanced propulsion systems will be presented. The goal is to provide an overview of NASA-Marshall Space Flight Center's on-going activities in MMC components for advanced liquid rocket engines such as the X-33 vehicle's Aerospike engine and X-34's Fastrac engine. The focus will be on lightweight, low cost, and environmental compatibility with oxygen and hydrogen of key MMC materials, within each of NASA's new propulsion application, that will provide a high payoff for NASA's Reusable Launch Vehicles and space access vehicles. In order to fabricate structures from MMC, effective joining methods must be developed to join MMC to the same or to different monolithic alloys. Therefore, a qualitative assessment of MMC's welding and joining techniques will be outlined.
Accurate crop classification using hierarchical genetic fuzzy rule-based systems
NASA Astrophysics Data System (ADS)
Topaloglou, Charalampos A.; Mylonas, Stelios K.; Stavrakoudis, Dimitris G.; Mastorocostas, Paris A.; Theocharis, John B.
2014-10-01
This paper investigates the effectiveness of an advanced classification system for accurate crop classification using very high resolution (VHR) satellite imagery. Specifically, a recently proposed genetic fuzzy rule-based classification system (GFRBCS) is employed, namely, the Hierarchical Rule-based Linguistic Classifier (HiRLiC). HiRLiC's model comprises a small set of simple IF-THEN fuzzy rules, easily interpretable by humans. One of its most important attributes is that its learning algorithm requires minimum user interaction, since the most important learning parameters affecting the classification accuracy are determined by the learning algorithm automatically. HiRLiC is applied in a challenging crop classification task, using a SPOT5 satellite image over an intensively cultivated area in a lake-wetland ecosystem in northern Greece. A rich set of higher-order spectral and textural features is derived from the initial bands of the (pan-sharpened) image, resulting in an input space comprising 119 features. The experimental analysis proves that HiRLiC compares favorably to other interpretable classifiers of the literature, both in terms of structural complexity and classification accuracy. Its testing accuracy was very close to that obtained by complex state-of-the-art classification systems, such as the support vector machines (SVM) and random forest (RF) classifiers. Nevertheless, visual inspection of the derived classification maps shows that HiRLiC is characterized by higher generalization properties, providing more homogeneous classifications that the competitors. Moreover, the runtime requirements for producing the thematic map was orders of magnitude lower than the respective for the competitors.
Metal-insulator transition in disordered systems from the one-body density matrix
NASA Astrophysics Data System (ADS)
Olsen, Thomas; Resta, Raffaele; Souza, Ivo
2017-01-01
The insulating state of matter can be probed by means of a ground state geometrical marker, which is closely related to the modern theory of polarization (based on a Berry phase). In the present work we show that this marker can be applied to determine the metal-insulator transition in disordered systems. In particular, for noninteracting systems the geometrical marker can be obtained from the configurational average of the norm-squared one-body density matrix, which can be calculated within open as well as periodic boundary conditions. This is in sharp contrast to a classification based on the static conductivity, which is only sensible within periodic boundary conditions. We exemplify the method by considering a simple lattice model, known to have a metal-insulator transition as a function of the disorder strength, and demonstrate that the transition point can be obtained accurately from the one-body density matrix. The approach has a general ab initio formulation and could in principle be applied to realistic disordered materials by standard electronic structure methods.
Gold nanospikes based microsensor as a highly accurate mercury emission monitoring system
Sabri, Ylias M.; Ippolito, Samuel J.; Tardio, James; Bansal, Vipul; O'Mullane, Anthony P.; Bhargava, Suresh K.
2014-01-01
Anthropogenic elemental mercury (Hg0) emission is a serious worldwide environmental problem due to the extreme toxicity of the heavy metal to humans, plants and wildlife. Development of an accurate and cheap microsensor based online monitoring system which can be integrated as part of Hg0 removal and control processes in industry is still a major challenge. Here, we demonstrate that forming Au nanospike structures directly onto the electrodes of a quartz crystal microbalance (QCM) using a novel electrochemical route results in a self-regenerating, highly robust, stable, sensitive and selective Hg0 vapor sensor. The data from a 127 day continuous test performed in the presence of volatile organic compounds and high humidity levels, showed that the sensor with an electrodeposted sensitive layer had 260% higher response magnitude, 3.4 times lower detection limit (~22 μg/m3 or ~2.46 ppbv) and higher accuracy (98% Vs 35%) over a Au control based QCM (unmodified) when exposed to a Hg0 vapor concentration of 10.55 mg/m3 at 101°C. Statistical analysis of the long term data showed that the nano-engineered Hg0 sorption sites on the developed Au nanospikes sensitive layer play a critical role in the enhanced sensitivity and selectivity of the developed sensor towards Hg0 vapor. PMID:25338965
NASA Technical Reports Server (NTRS)
Alter, Stephen J.; Brauckmann, Gregory J.; Kleb, William L.; Glass, Christopher E.; Streett, Craig L.; Schuster, David M.
2015-01-01
A transonic flow field about a Space Launch System (SLS) configuration was simulated with the Fully Unstructured Three-Dimensional (FUN3D) computational fluid dynamics (CFD) code at wind tunnel conditions. Unsteady, time-accurate computations were performed using second-order Delayed Detached Eddy Simulation (DDES) for up to 1.5 physical seconds. The surface pressure time history was collected at 619 locations, 169 of which matched locations on a 2.5 percent wind tunnel model that was tested in the 11 ft. x 11 ft. test section of the NASA Ames Research Center's Unitary Plan Wind Tunnel. Comparisons between computation and experiment showed that the peak surface pressure RMS level occurs behind the forward attach hardware, and good agreement for frequency and power was obtained in this region. Computational domain, grid resolution, and time step sensitivity studies were performed. These included an investigation of pseudo-time sub-iteration convergence. Using these sensitivity studies and experimental data comparisons, a set of best practices to date have been established for FUN3D simulations for SLS launch vehicle analysis. To the author's knowledge, this is the first time DDES has been used in a systematic approach and establish simulation time needed, to analyze unsteady pressure loads on a space launch vehicle such as the NASA SLS.
SANTHANAKRISHNAN, ARVIND; NESTLE, TRENT T.; MOORE, BRIAN L.; YOGANATHAN, AJIT P.; PADEN, MATTHEW L.
2013-01-01
Acute kidney injury is common in critically ill children and renal replacement therapies provide a life saving therapy to a subset of these children. However, there is no Food and Drug Administration approved device to provide pediatric continuous renal replacement therapy (CRRT). Consequently, clinicians adapt approved adult CRRT devices for use in children due to lack of safer alternatives. Complications occur using adult CRRT devices in children due to inaccurate fluid balance (FB) between the volumes of ultrafiltrate (UF) removed and replacement fluid (RF) delivered. We demonstrate the design and validation of a pediatric fluid management system for obtaining accurate instantaneous and cumulative FB. Fluid transport was achieved via multiple novel pulsatile diaphragm pumps. The conservation of volume principle leveraging the physical property of fluid incompressibility along with mechanical coupling via a crankshaft was used for FB. Accuracy testing was conducted in vitro for 8-hour long continuous operation of the coupled UF and RF pumps. The mean cumulative FB error was <1% across filtration flows from 300 mL/hour to 3000 mL/hour. This approach of FB control in a pediatric specific CRRT device would represent a significant accuracy improvement over currently used clinical implementations. PMID:23644618
NASA Astrophysics Data System (ADS)
Hollstein, André; Fischer, Jürgen
2012-05-01
Accurate radiative transfer models are the key tools for the understanding of radiative transfer processes in the atmosphere and ocean, and for the development of remote sensing algorithms. The widely used scalar approximation of radiative transfer can lead to errors in calculated top of atmosphere radiances. We show results with errors in the order of±8% for atmosphere ocean systems with case one waters. Variations in sea water salinity and temperature can lead to variations in the signal of similar magnitude. Therefore, we enhanced our scalar radiative transfer model MOMO, which is in use at Freie Universität Berlin, to treat these effects as accurately as possible. We describe our one-dimensional vector radiative transfer model for an atmosphere ocean system with a rough interface. We describe the matrix operator scheme and the bio-optical model for case one waters. We discuss some effects of neglecting polarization in radiative transfer calculations and effects of salinity changes for top of atmosphere radiances. Results are shown for the channels of the satellite instruments MERIS and OLCI from 412.5 nm to 900 nm.
Modal cost analysis for linear matrix-second-order systems
NASA Technical Reports Server (NTRS)
Skelton, R. E.; Hughes, P. C.
1980-01-01
Reduced models and reduced controllers for systems governed by matrix-second-order differential equations are obtained by retaining those modes which make the largest contributions to quadratic control objectives. Such contributions, expressed in terms of modal data, used as mode truncation criteria, allow the statement of the specific control objectives to influence the early model reduction from very high order models which are available, for example, from finite element methods. The relative importance of damping, frequency, and eigenvector in the mode truncation decisions are made explicit for each of these control objectives: attitude control, vibration suppression and figure control. The paper also shows that using modal cost analysis (MCA) on the closed loop modes of the optimally controlled system allows the construction of reduced control policies which feedback only those closed loop modal coordinates which are most critical to the quadratic control performance criterion. In this way, the modes which should be controlled (and hence the modes which must be observable by choice of measurements), are deduced from truncations of the optimal controller.
PHARMACODYNAMICAL EVALUATION OF MATRIX TYPE TRANSDERMAL THERAPEUTIC SYSTEMS CONTAINING CAPTOPRIL.
Kerımoğlu, Oya; Şahbaz, Sevınç; Şehırlı, Özer; Ozdemır, Zarıfe Nıgar; Çetınel, Şule; Dortunç, Betül; Şener, Göksel
2015-01-01
The objective of this study was to evaluate pharmacodynamical properties of transdermal therapeutic systems (TTS) containing captopril together with synthetic and pH independent polymers, Eudragit RL 100 and RS 100. Optimum formulation was chosen according to the results of our previous study regarding in vitro dissolution and ex vivo diffusion rate studies through excised human skin by using Franz Diffusion Cell. Control group, hypertension group (HT) and TTS containing captopril hypertension group (HT-CAP) were assessed for the pharmacodynamic activity of the study. Pharmacodynamic activity of transdermal patches containing captopril was evaluated in rats by the measurement of systolic blood pressure for 24 h with the use of the tail cuff method. Blood pressure, heart rate, body and heart weight, heart and body weight ratio were determined. Lactate dehydrogenase (LDH), creatinine phosphokinase (CPK), glutathione (GSH), malondialdehyde (MDA), myeloperoxidase (MPO) and Na+, K(+)-ATPase were measured in the serum of rats. Histopathological evaluation of the heart tissue was conducted in order to determine any tissue damage. Blood pressure values of the TTS containing captopril hypertension group were decreased significantly and became almost similar with the blood pressure values of the control group. These results indicated that matrix type transdermal patches prepared with Eudragit RL 100 and RS 100 polymers containing captopril can be considered as transdermal therapeutic systems for chronical treatment of hypertension and congestive heart failure. However, further in vivo pharmacokinetic studies should be performed in order to determine the blood level of the drug.
Accurate ab Initio Spin Densities.
Boguslawski, Katharina; Marti, Konrad H; Legeza, Ors; Reiher, Markus
2012-06-12
We present an approach for the calculation of spin density distributions for molecules that require very large active spaces for a qualitatively correct description of their electronic structure. Our approach is based on the density-matrix renormalization group (DMRG) algorithm to calculate the spin density matrix elements as a basic quantity for the spatially resolved spin density distribution. The spin density matrix elements are directly determined from the second-quantized elementary operators optimized by the DMRG algorithm. As an analytic convergence criterion for the spin density distribution, we employ our recently developed sampling-reconstruction scheme [J. Chem. Phys.2011, 134, 224101] to build an accurate complete-active-space configuration-interaction (CASCI) wave function from the optimized matrix product states. The spin density matrix elements can then also be determined as an expectation value employing the reconstructed wave function expansion. Furthermore, the explicit reconstruction of a CASCI-type wave function provides insight into chemically interesting features of the molecule under study such as the distribution of α and β electrons in terms of Slater determinants, CI coefficients, and natural orbitals. The methodology is applied to an iron nitrosyl complex which we have identified as a challenging system for standard approaches [J. Chem. Theory Comput.2011, 7, 2740].
NASA Technical Reports Server (NTRS)
Pototzky, Anthony S.
2008-01-01
A simple matrix polynomial approach is introduced for approximating unsteady aerodynamics in the s-plane and ultimately, after combining matrix polynomial coefficients with matrices defining the structure, a matrix polynomial of the flutter equations of motion (EOM) is formed. A technique of recasting the matrix-polynomial form of the flutter EOM into a first order form is also presented that can be used to determine the eigenvalues near the origin and everywhere on the complex plane. An aeroservoelastic (ASE) EOM have been generalized to include the gust terms on the right-hand side. The reasons for developing the new matrix polynomial approach are also presented, which are the following: first, the "workhorse" methods such as the NASTRAN flutter analysis lack the capability to consistently find roots near the origin, along the real axis or accurately find roots farther away from the imaginary axis of the complex plane; and, second, the existing s-plane methods, such as the Roger s s-plane approximation method as implemented in ISAC, do not always give suitable fits of some tabular data of the unsteady aerodynamics. A method available in MATLAB is introduced that will accurately fit generalized aerodynamic force (GAF) coefficients in a tabular data form into the coefficients of a matrix polynomial form. The root-locus results from the NASTRAN pknl flutter analysis, the ISAC-Roger's s-plane method and the present matrix polynomial method are presented and compared for accuracy and for the number and locations of roots.
Generalized Fisher information matrix in nonextensive systems with spatial correlation
NASA Astrophysics Data System (ADS)
Hasegawa, Hideo
2009-11-01
By using the q -Gaussian distribution derived by the maximum entropy method for spatially correlated N -unit nonextensive systems, we have calculated the generalized Fisher information matrix of gθnθm for (θ1,θ2,θ3)=(μq,σq2,s) , where μq , σq2 , and s denote the mean, variance, and degree of spatial correlation, respectively, for a given entropic index q . It has been shown from the Cramér-Rao theorem that (1) an accuracy of an unbiased estimate of μq is improved (degraded) by a negative (positive) correlation s , (2) that of σq2 is worsen with increasing s , and (3) that of s is much improved for s≃-1/(N-1) or s≃1.0 though it is worst at s=(N-2)/2(N-1) . Our calculation provides a clear insight to the long-standing controversy whether the spatial correlation is beneficial or detrimental to decoding in neuronal ensembles. We discuss also a calculation of the q -Gaussian distribution applying the superstatistics to the Langevin model subjected to spatially correlated inputs.
The accurate use of impedance analysis for the study of microbial electrochemical systems.
Dominguez-Benetton, Xochitl; Sevda, Surajbhan; Vanbroekhoven, Karolien; Pant, Deepak
2012-11-07
The present critical review aims to portray the principles and theoretical foundations that have been used for the application of electrochemical impedance spectroscopy (EIS) to study electron-transfer mechanisms, mass transfer phenomena and distribution of the heterogeneous properties of microbial electrochemical systems (MXCs). Over the past eight years, the application of this method has allowed major breakthroughs, especially in the field of microbial fuel cells (MFCs); however, it is still most widely extended only to the calculation of internal resistances. The use and interpretation of EIS should greatly improve since the intrinsic knowledge of this field, and efforts and current trends in this field have already allowed its understanding based on rather meaningful physical properties and not only on fitting electrical analogues. From this perspective, the use, analysis and interpretation of EIS applied to the study of MXCs are critically examined. Together with the revision of more than 150 articles directly devoted to this topic, two examples of the correct and improved analysis of EIS data are extensively presented. The first one focuses on the use of graphical methods for improving EIS analysis and the other one concentrates on the elucidation of the constant phase element (CPE) parameters. CPEs have been introduced in equivalent circuit models, sometimes without solid justification or analysis; the effective capacitance has been obtained from CPE parameters, following an unsuitable theory for the case of microbial-electrochemical interfaces. The use of CPE is reviewed in terms of meaningful physical parameters, such as biofilm thickness. The use of a finite-diffusion element is reviewed throughout estimation of accurate values for obtaining the dimensionless numbers, Schmidt and Sherwood, in the context of a dioxygen-reducing-biocathode, under different flow-rate conditions. The use and analysis of EIS in this context are still emerging, but because of
Lee, Ping I
2011-10-10
The purpose of this review is to provide an overview of approximate analytical solutions to the general moving boundary diffusion problems encountered during the release of a dispersed drug from matrix systems. Starting from the theoretical basis of the Higuchi equation and its subsequent improvement and refinement, available approximate analytical solutions for the more complicated cases involving heterogeneous matrix, boundary layer effect, finite release medium, surface erosion, and finite dissolution rate are also discussed. Among various modeling approaches, the pseudo-steady state assumption employed in deriving the Higuchi equation and related approximate analytical solutions appears to yield reasonably accurate results in describing the early stage release of a dispersed drug from matrices of different geometries whenever the initial drug loading (A) is much larger than the drug solubility (C(s)) in the matrix (or A≫C(s)). However, when the drug loading is not in great excess of the drug solubility (i.e. low A/C(s) values) or when the drug loading approaches the drug solubility (A→C(s)) which occurs often with drugs of high aqueous solubility, approximate analytical solutions based on the pseudo-steady state assumption tend to fail, with the Higuchi equation for planar geometry exhibiting a 11.38% error as compared with the exact solution. In contrast, approximate analytical solutions to this problem without making the pseudo-steady state assumption, based on either the double-integration refinement of the heat balance integral method or the direct simplification of available exact analytical solutions, show close agreement with the exact solutions in different geometries, particularly in the case of low A/C(s) values or drug loading approaching the drug solubility (A→C(s)). However, the double-integration heat balance integral approach is generally more useful in obtaining approximate analytical solutions especially when exact solutions are not
Direct Measurement of the Density Matrix of a Quantum System
NASA Astrophysics Data System (ADS)
Thekkadath, G. S.; Giner, L.; Chalich, Y.; Horton, M. J.; Banker, J.; Lundeen, J. S.
2016-09-01
One drawback of conventional quantum state tomography is that it does not readily provide access to single density matrix elements since it requires a global reconstruction. Here, we experimentally demonstrate a scheme that can be used to directly measure individual density matrix elements of general quantum states. The scheme relies on measuring a sequence of three observables, each complementary to the last. The first two measurements are made weak to minimize the disturbance they cause to the state, while the final measurement is strong. We perform this joint measurement on polarized photons in pure and mixed states to directly measure their density matrix. The weak measurements are achieved using two walk-off crystals, each inducing a polarization-dependent spatial shift that couples the spatial and polarization degrees of freedom of the photons. This direct measurement method provides an operational meaning to the density matrix and promises to be especially useful for large dimensional states.
Experimental results for improving the matrix condition using a hybrid optical system.
Klapp, Iftach; Mendlovic, David
2012-03-01
We present preliminary experimental results for implementing the "blurred trajectories" method on three parallel optics (PO) systems. The "main" system and "auxiliary" optics were simple laboratory graded lenses attached to an iris diaphragm. When applying the blurred trajectories method we first show an improvement in the matrix condition, as the matrix condition number decreased in a range of factors of 3 to 418 relative to the main system. Following that, image restoration by weak regularization was performed so that the system matrix condition dominated the restoration process. It was shown that the restoration results of the PO are better than those of the main system and the auxiliary optics separately. In addition, the quality of the restoration follows the system's matrix condition. The improvement in the matrix condition achieved by the PO system improved the immunity to detection noise. Finally, a comparison to Wiener filtering restoration shows that it is also generally inferior to the proposed method.
Effects of lattice morphology upon reaction dynamics in matrix-isolated systems
NASA Astrophysics Data System (ADS)
Raff, Lionel M.
1992-11-01
The dynamics of the cis-d2-ethylene+F2 addition reaction and the subsequent reaction dynamics of the products isolated in vapor-deposited Ar matrices at 12 K are investigated using trajectory methods that incorporate nonstatistical sampling to enhance the reaction probabilities. The matrix-isolated cis-d2-ethylene+F2 system is generated using a combination of Monte Carlo, damped trajectory, and volume contraction methods. Transport effects of the bulk are simulated using the velocity reset procedure developed by Riley et al. [J. Chem. Phys. 88, 5934 (1988)]. The potential-energy hypersurface is the same as that employed in our previous investigations of the matrix-isolated, decomposition dynamics of 1,2-difluoroethane-d4 and the bimolecular cis-d2-ethylene+F2 system in face-centered-cubic (fcc) matrices [J. Chem. Phys. 93, 3160 (1990); 95, 8901 (1991)]. It is found that matrices generated by these methods are amorphous with numerous vacancies and other imperfections. On the average, there are approximately three vacancies about each lattice atom compared to the fcc crystal. The calculated lattice density is about 82% that for a bulk fcc Ar solid. Computed radial distribution functions resemble those expected for a liquid which exhibits some short-range order. The imperfections of the lattice remain even after substantial annealing at 50 K. The calculated energy relaxation rate to the lattice phonon modes in these amorphous matrices is about a factor of 4 less than that for a close-packed fcc lattice. The 1,2-difluoroethane product is formed primarily via an αβ-addition process, as is the case for fcc matrices. However, the prominence of this pathway is greatly reduced. The major process leading to a fluoroethylene elimination product in amorphous matrices involves an atomic addition mechanism. Such a reaction path accounts for 94% of the elimination reactions. The probability of internal rotation about the C■C double bond in the fluoroethylene product is
Matrix embedded microspherules containing indomethacin as controlled drug delivery systems.
Swamy, K M Lokamatha; Satyanath, B; Shantakumar, S M; Manjula, D; Mohammedi, Hafsa; Farhana, Ayesha
2008-10-01
This work is focused on the development of controlled drug delivery systems using different wax/fat embedded indomethacin (IM). Discrete wax/fat embedded microspherules containing indomethacin were prepared by using cetostearyl alcohol, paraffin wax and stearic acid by employing emulsification-phase separation method. These matrices have been used as barrier coatings due to their hydrophobic nature. Chemically inert and tasteless nature of wax/fats promotes their use as taste masking agents for bitter drugs. Various waxes and fats are available having different physicochemical properties to suit the needs of formulation. Methyl cellulose (MC) 1% w/v, sodium alginate (SA) 0.5% w/v and Tween-80 (TW) 1% w/v were used as emulgents. The resulting microspherules were discrete, large, spherical and also free flowing. It is revealed from the literature that natures of wax/fat emulgents were found to influence the rate of drug release. In the present work the drug content in all the batches of microspherules were found to be uniform. The rate of drug release corresponded best to first order kinetics, followed by Higuchi and zero-order equations. The release of the model drug from these wax/fat microspherules was prolonged over an extended period of time and the drug release mechanism followed anomalous (non-Fickian) diffusion controlled as well as Super Case II transport. Among the three matrix materials used, paraffin wax retarded the drug release more than the other two. Surface characteristics of microspherules have been studied by Scanning Electron Microscope (SEM). A fair degree rank of correlation was found to exist between the size and release retardation in all the three-wax/fat emulgent combinations.
Periosteal Sharpey's fibers: a novel bone matrix regulatory system?
Aaron, Jean E
2012-01-01
Sharpey's "perforating" fibers (SF) are well known skeletally in tooth anchorage. Elsewhere they provide anchorage for the periosteum and are less well documented. Immunohistochemistry has transformed their potential significance by identifying their collagen type III (CIII) content and enabling their mapping in domains as permeating arrays of fibers (5-25 μ thick), protected from osteoclastic resorption by their poor mineralization. As periosteal extensions they are crucial in early skeletal development and central to intramembranous bone healing, providing unique microanatomical avenues for musculoskeletal exchange, their composition (e.g., collagen type VI, elastin, tenascin) combined with a multiaxial pattern of insertion suggesting a role more complex than attachment alone would justify. A proportion permeate the cortex to the endosteum (and beyond), fusing into a CIII-rich osteoid layer (<2 μ thick) encompassing all resting surfaces, and with which they apparently integrate into a PERIOSTEAL-SHARPEY FIBER-ENDOSTEUM (PSE) structural continuum. This intraosseous system behaves in favor of bone loss or gain depending upon extraneous stimuli (i.e., like Frost's hypothetical "mechanostat"). Thus, the birefringent fibers are sensitive to humoral factors (e.g., estrogen causes retraction, rat femur model), physical activity (e.g., running causes expansion, rat model), aging (e.g., causes fragmentation, pig mandible model), and pathology (e.g., atrophied in osteoporosis, hypertrophied in osteoarthritis, human proximal femur), and with encroaching mineral particles hardening the usually soft parts. In this way the unobtrusive periosteal SF network may regulate bone status, perhaps even contributing to predictable "hotspots" of trabecular disconnection, particularly at sites of tension prone to fatigue, and with the network deteriorating significantly before bone matrix loss.
Kwak, Hye-Lim; Han, Sun-Kyung; Park, Sunghoon; Park, Si Hong; Shim, Jae-Yong; Oh, Mihwa; Ricke, Steven C; Kim, Hae-Yeong
2015-09-01
Previous detection methods for Citrobacter are considered time consuming and laborious. In this study, we have developed a rapid and accurate detection method for Citrobacter species in pork products, using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). A total of 35 Citrobacter strains were isolated from 30 pork products and identified by both MALDI-TOF MS and 16S rRNA gene sequencing approaches. All isolates were identified to the species level by the MALDI-TOF MS, while 16S rRNA gene sequencing results could not discriminate them clearly. These results confirmed that MALDI-TOF MS is a more accurate and rapid detection method for the identification of Citrobacter species.
Accurate Hartree-Fock energy of extended systems using large Gaussian basis sets
NASA Astrophysics Data System (ADS)
Paier, Joachim; Diaconu, Cristian V.; Scuseria, Gustavo E.; Guidon, Manuel; Vandevondele, Joost; Hutter, Jürg
2009-11-01
Calculating highly accurate thermochemical properties of condensed matter via wave-function-based approaches (such as, e.g., Hartree-Fock or hybrid functionals) has recently attracted much interest. We here present two strategies providing accurate Hartree-Fock energies for solid LiH in a large Gaussian basis set and applying periodic boundary conditions. The total energies were obtained using two different approaches, namely, a supercell evaluation of Hartree-Fock exchange using a truncated Coulomb operator and an extrapolation toward the full-range Hartree-Fock limit of a Padé fit to a series of short-range screened Hartree-Fock calculations. These two techniques agreed to significant precision. We also present the Hartree-Fock cohesive energy of LiH (converged to within sub-millielectron volt) at the experimental equilibrium volume as well as the Hartree-Fock equilibrium lattice constant and bulk modulus.
Matrix formulation of a universal microbial transcript profiling system
Fitch, J P; Ng, J; Sokhansanj, B A
2000-11-01
DNA chips and microarrays are used to profile gene transcription. Unfortunately, the initial fabrication cost for a chip and the reagent costs to amplify thousands of open reading frames for a microarray are over $100K for a typical 4 Mbase bacterial genome. To avoid these expensive steps, a matrix formulation of a universal hybrid chip-microarray approach to transcript profiling is demonstrated for synthetic data. Initial considerations for application to the 4.3 Mbase bacterium Yersinia pestis are also presented. This approach can be applied to arbitrary bacteria by recalculating a matrix and pseudoinverse. This approach avoids the large upfront expenses associated with DNA chips and microarrays.
Bertels, Luke W.; Mazziotti, David A.
2014-07-28
Multireference correlation in diradical molecules can be captured by a single-reference 2-electron reduced-density-matrix (2-RDM) calculation with only single and double excitations in the 2-RDM parametrization. The 2-RDM parametrization is determined by N-representability conditions that are non-perturbative in their treatment of the electron correlation. Conventional single-reference wave function methods cannot describe the entanglement within diradical molecules without employing triple- and potentially even higher-order excitations of the mean-field determinant. In the isomerization of bicyclobutane to gauche-1,3-butadiene the parametric 2-RDM (p2-RDM) method predicts that the diradical disrotatory transition state is 58.9 kcal/mol above bicyclobutane. This barrier is in agreement with previous multireference calculations as well as recent Monte Carlo and higher-order coupled cluster calculations. The p2-RDM method predicts the Nth natural-orbital occupation number of the transition state to be 0.635, revealing its diradical character. The optimized geometry from the p2-RDM method differs in important details from the complete-active-space self-consistent-field geometry used in many previous studies including the Monte Carlo calculation.
NASA Astrophysics Data System (ADS)
Calvo, F.; Falvo, Cyril; Parneix, Pascal
2013-01-01
An explicit polarizable potential for the naphthalene-argon complex has been derived assuming only atomic contributions, aiming at large scale simulations of naphthalene under argon environment. The potential was parametrized from dedicated quantum chemical calculations at the CCSD(T) level, and satisfactorily reproduces available structural and energetic properties. Combining this potential with a tight-binding model for naphthalene, collisional energy transfer is studied by means of dedicated molecular dynamics simulations, nuclear quantum effects being accounted for in the path-integral framework. Except at low target temperature, nuclear quantum effects do not alter the average energies transferred by the collision or the collision duration. However, the distribution of energy transferred is much broader in the quantum case due to the significant zero-point energy and the higher density of states. Using an ab initio potential for the Ar-Ar interaction, the IR absorption spectrum of naphthalene solvated by argon clusters or an entire Ar matrix is computed via classical and centroid molecular dynamics. The classical spectra exhibit variations with growing argon environment that are absent from quantum spectra. This is interpreted by the greater fluxional character experienced by the argon atoms due to vibrational delocalization.
Calvo, F; Falvo, Cyril; Parneix, Pascal
2013-01-21
An explicit polarizable potential for the naphthalene-argon complex has been derived assuming only atomic contributions, aiming at large scale simulations of naphthalene under argon environment. The potential was parametrized from dedicated quantum chemical calculations at the CCSD(T) level, and satisfactorily reproduces available structural and energetic properties. Combining this potential with a tight-binding model for naphthalene, collisional energy transfer is studied by means of dedicated molecular dynamics simulations, nuclear quantum effects being accounted for in the path-integral framework. Except at low target temperature, nuclear quantum effects do not alter the average energies transferred by the collision or the collision duration. However, the distribution of energy transferred is much broader in the quantum case due to the significant zero-point energy and the higher density of states. Using an ab initio potential for the Ar-Ar interaction, the IR absorption spectrum of naphthalene solvated by argon clusters or an entire Ar matrix is computed via classical and centroid molecular dynamics. The classical spectra exhibit variations with growing argon environment that are absent from quantum spectra. This is interpreted by the greater fluxional character experienced by the argon atoms due to vibrational delocalization.
NASA Astrophysics Data System (ADS)
Huang, Y. S.; Huang, Y. P.; Huang, K. N.; Young, M. S.
2007-11-01
A new microcomputer based air temperature measurement system is presented. An accurate temperature measurement is derived from the measurement of sound velocity by using an ultrasonic time-of-flight (TOF) technique. The study proposes a novel algorithm that combines both amplitude modulation (AM) and phase modulation (PM) to get the TOF measurement. The proposed system uses the AM and PM envelope square waveform (APESW) to reduce the error caused by inertia delay. The APESW ultrasonic driving waveform causes an envelope zero and phase inversion phenomenon in the relative waveform of the receiver. To accurately achieve a TOF measurement, the phase inversion phenomenon was used to sufficiently identify the measurement pulse in the received waveform. Additionally, a counter clock technique was combined to compute the phase shifts of the last incomplete cycle for TOF. The presented system can obtain 0.1% TOF resolution for the period corresponding to the 40kHz frequency ultrasonic wave. Consequently, with the integration of a humidity compensation algorithm, a highly accurate and high resolution temperature measurement can be achieved using the accurate TOF measurement. Experimental results indicate that the combined standard uncertainty of the temperature measurement is approximately 0.39°C. The main advantages of this system are high resolution measurements, narrow bandwidth requirements, and ease of implementation.
MatrixExplorer: a dual-representation system to explore social networks.
Henry, Nathalie; Fekete, Jean-Daniel
2006-01-01
MatrixExplorer is a network visualization system that uses two representations: node-link diagrams and matrices. Its design comes from a list of requirements formalized after several interviews and a participatory design session conducted with social science researchers. Although matrices are commonly used in social networks analysis, very few systems support the matrix-based representations to visualize and analyze networks. MatrixExplorer provides several novel features to support the exploration of social networks with a matrix-based representation, in addition to the standard interactive filtering and clustering functions. It provides tools to reorder (layout) matrices, to annotate and compare findings across different layouts and find consensus among several clusterings. MatrixExplorer also supports Node-link diagram views which are familiar to most users and remain a convenient way to publish or communicate exploration results. Matrix and node-link representations are kept synchronized at all stages of the exploration process.
Chan, T W D; Duan, L; Sze, T P E
2002-10-15
A new analytical scheme based on a combination of scanning FTMS, multiple-ion filling, and potential ramping methods has been developed for accurate molecular mass measurement of peptide and protein mixtures using broadband MALDI-FTMS. The scanning FTMS method alleviates the problems of time-of-flight effect for FTMS with an external MALDI ion source and provides a systematic means of sampling ions of different mass-to-charge ratios. The multiple-ion filling method is an effective way of trapping and retaining ions from successive ion generation/accumulation events. The potential ramping method allows the use of high trapping potentials for effective trapping of ions of high kinetic energies and the use of low trapping potentials for high-resolution detection of the trapped ions. With this analytical scheme, high-resolution broadband MALDI mass spectra covering a wide mass range of 1000-5700 Da were obtained. For peptide mixtures of mass range 1000-3500 Da, calibration errors of low part-per-millions were demonstrated using a parabolic calibration equation f2 = ML1/m2 + ML2/m + ML3, where f is the measured cyclotron frequency and ML1, ML2, and ML3 are calibration constants.
Test system accurately determines tensile properties of irradiated metals at cryogenic temperatures
NASA Technical Reports Server (NTRS)
Levine, P. J.; Skalka, R. J.; Vandergrift, E. F.
1967-01-01
Modified testing system determines tensile properties of irradiated brittle-type metals at cryogenic temperatures. The system includes a lightweight cryostat, split-screw grips, a universal joint, and a special temperature control system.
Digital-coded matrix system simplifies design and construction of flow charts
NASA Technical Reports Server (NTRS)
Otoole, E.
1971-01-01
Matrix system utilizing unique digital code enables drawing block diagrams with parallel blocks. Complete freedom is obtained in laying out diagram, and it is possible to go directly from matrix to finished drawing. Need to rough out diagram is eliminated and time involved is greatly reduced.
Chaturvedi, Vishal; Dye, Danielle E; Kinnear, Beverley F; van Kuppevelt, Toin H; Grounds, Miranda D; Coombe, Deirdre R
2015-01-01
Decellularisation of skeletal muscle provides a system to study the interactions of myoblasts with muscle extracellular matrix (ECM). This study describes the efficient decellularisation of quadriceps muscle with the retention of matrix components and the use of this matrix for myoblast proliferation and differentiation under serum free culture conditions. Three decellularisation approaches were examined; the most effective was phospholipase A2 treatment, which removed cellular material while maximizing the retention of ECM components. Decellularised muscle matrices were then solubilized and used as substrates for C2C12 mouse myoblast serum free cultures. The muscle matrix supported myoblast proliferation and differentiation equally as well as collagen and fibronectin. Immunofluorescence analyses revealed that myoblasts seeded on muscle matrix and fibronectin differentiated to form long, well-aligned myotubes, while myoblasts seeded on collagen were less organized. qPCR analyses showed a time dependent increase in genes involved in skeletal muscle differentiation and suggested that muscle-derived matrix may stimulate an increased rate of differentiation compared to collagen and fibronectin. Decellularized whole muscle three-dimensional scaffolds also supported cell adhesion and spreading, with myoblasts aligning along specific tracts of matrix proteins within the scaffolds. Thus, under serum free conditions, intact acellular muscle matrices provided cues to direct myoblast adhesion and migration. In addition, myoblasts were shown to rapidly secrete and organise their own matrix glycoproteins to create a localized ECM microenvironment. This serum free culture system has revealed that the correct muscle ECM facilitates more rapid cell organisation and differentiation than single matrix glycoprotein substrates.
Zhang, Weipeng; Sun, Jin; Ding, Wei; Lin, Jinshui; Tian, Renmao; Lu, Liang; Liu, Xiaofen; Shen, Xihui; Qian, Pei-Yuan
2015-01-01
Though the essential role of extracellular matrix in biofilm development has been extensively documented, the function of matrix-associated proteins is elusive. Determining the dynamics of matrix-associated proteins would be a useful way to reveal their functions in biofilm development. Therefore, we applied iTRAQ-based quantitative proteomics to evaluate matrix-associated proteins isolated from different phases of Pseudomonas aeruginosa ATCC27853 biofilms. Among the identified 389 proteins, 54 changed their abundance significantly. The increased abundance of stress resistance and nutrient metabolism-related proteins over the period of biofilm development was consistent with the hypothesis that biofilm matrix forms micro-environments in which cells are optimally organized to resist stress and use available nutrients. Secreted proteins, including novel putative effectors of the type III secretion system were identified, suggesting that the dynamics of pathogenesis-related proteins in the matrix are associated with biofilm development. Interestingly, there was a good correlation between the abundance changes of matrix-associated proteins and their expression. Further analysis revealed complex interactions among these modulated proteins, and the mutation of selected proteins attenuated biofilm development. Collectively, this work presents the first dynamic picture of matrix-associated proteins during biofilm development, and provides evidences that the matrix-associated proteins may form an integral and well regulated system that contributes to stress resistance, nutrient acquisition, pathogenesis and the stability of the biofilm. PMID:26029669
Matrix-Product-State Algorithm for Finite Fractional Quantum Hall Systems
NASA Astrophysics Data System (ADS)
Liu, Zhao; Bhatt, R. N.
2015-09-01
Exact diagonalization is a powerful tool to study fractional quantum Hall (FQH) systems. However, its capability is limited by the exponentially increasing computational cost. In order to overcome this difficulty, density-matrix-renormalization-group (DMRG) algorithms were developed for much larger system sizes. Very recently, it was realized that some model FQH states have exact matrix-product-state (MPS) representation. Motivated by this, here we report a MPS code, which is closely related to, but different from traditional DMRG language, for finite FQH systems on the cylinder geometry. By representing the many-body Hamiltonian as a matrix-product-operator (MPO) and using single-site update and density matrix correction, we show that our code can efficiently search the ground state of various FQH systems. We also compare the performance of our code with traditional DMRG. The possible generalization of our code to infinite FQH systems and other physical systems is also discussed.
Roberts, Grace C.; Morris, Paul G.; Moss, Marcus A.; Maltby, Sarah L.; Palmer, Chelsea A.; Nash, Claire E.; Smart, Emily; Holliday, Deborah L.; Speirs, Valerie
2016-01-01
Background 3D cell cultures are emerging as more physiologically meaningful alternatives to monolayer cultures for many biological applications. They are attractive because they more closely mimic in vivo morphology, especially when co-cultured with stromal fibroblasts. Methodology/Principal Findings We compared the efficacy of 3 different 3D cell culture systems; collagen I, low attachment culture vessels and a modification of Fibrolife®, a specialised humanised cell culture medium devoid of animal-derived components, using breast cancer cell lines representative of the different molecular subtypes of breast cancer, cultured alone or with human mammary fibroblasts with a view to developing matrix-free humanised systems. 3D collagen I culture supported the growth of a range of breast cancer cell lines. By modifying the composition of Fibrolife® to epiFL, matrix-free cell culture was possible. During sequential transfer to epiFL breast cancer cells gradually detached from the flask, growing progressively as spheroids. Phenotype was stable and reversible with cells remaining actively proliferating and easily accessible throughout culture. They could also be revived from frozen stocks. To achieve co-culture with fibroblasts in epiFL required use of low attachment culture vessels instead of standard plastic as fibroblasts remained adherent in epiFL. Here, cancer cell spheroids were allowed to form before adding fibroblasts. Immunohistochemical examination showed fibroblasts scattered throughout the epithelial spheroid, not dissimilar to the relationship of tumour stroma in human breast cancer. Conclusions Because of its ease of handling, matrix-free 3D cell culture may be a useful model to study the influence of fibroblasts on breast cancer epithelial cells with use of epiFL culture medium taking this a step further towards a fully humanised 3D model. This methodology could be applied to other types of cancer cell lines, making this a versatile technique for cancer
Control and synchronizing nonlinear systems with delay based on a special matrix structure
NASA Astrophysics Data System (ADS)
Hu, Jianbing; Zhao, Lingdong; Xie, Zhenguang
2014-04-01
This work presents a direct approach to design stabilizing controller for nonlinear systems with delay based on a special matrix structure and proves the validity of the approach according to Lyapunov-Krasovskii stable theorem and Linear Matrix Inequality—LMI. Control Lorenz system and synchronizing Rössler system with delay are taken as examples to explain the approach. Numerical simulations confirm the effectiveness of the approach proposed.
Integrative systems and synthetic biology of cell-matrix adhesion sites
Zamir, Eli
2016-01-01
ABSTRACT The complexity of cell-matrix adhesion convolves its roles in the development and functioning of multicellular organisms and their evolutionary tinkering. Cell-matrix adhesion is mediated by sites along the plasma membrane that anchor the actin cytoskeleton to the matrix via a large number of proteins, collectively called the integrin adhesome. Fundamental challenges for understanding how cell-matrix adhesion sites assemble and function arise from their multi-functionality, rapid dynamics, large number of components and molecular diversity. Systems biology faces these challenges in its strive to understand how the integrin adhesome gives rise to functional adhesion sites. Synthetic biology enables engineering intracellular modules and circuits with properties of interest. In this review I discuss some of the fundamental questions in systems biology of cell-matrix adhesion and how synthetic biology can help addressing them. PMID:26853318
Automated MALDI Matrix Coating System for Multiple Tissue Samples for Imaging Mass Spectrometry
NASA Astrophysics Data System (ADS)
Mounfield, William P.; Garrett, Timothy J.
2012-03-01
Uniform matrix deposition on tissue samples for matrix-assisted laser desorption/ionization (MALDI) is key for reproducible analyte ion signals. Current methods often result in nonhomogenous matrix deposition, and take time and effort to produce acceptable ion signals. Here we describe a fully-automated method for matrix deposition using an enclosed spray chamber and spray nozzle for matrix solution delivery. A commercial air-atomizing spray nozzle was modified and combined with solenoid controlled valves and a Programmable Logic Controller (PLC) to control and deliver the matrix solution. A spray chamber was employed to contain the nozzle, sample, and atomized matrix solution stream, and to prevent any interference from outside conditions as well as allow complete control of the sample environment. A gravity cup was filled with MALDI matrix solutions, including DHB in chloroform/methanol (50:50) at concentrations up to 60 mg/mL. Various samples (including rat brain tissue sections) were prepared using two deposition methods (spray chamber, inkjet). A linear ion trap equipped with an intermediate-pressure MALDI source was used for analyses. Optical microscopic examination showed a uniform coating of matrix crystals across the sample. Overall, the mass spectral images gathered from tissues coated using the spray chamber system were of better quality and more reproducible than from tissue specimens prepared by the inkjet deposition method.
Automated MALDI matrix coating system for multiple tissue samples for imaging mass spectrometry.
Mounfield, William P; Garrett, Timothy J
2012-03-01
Uniform matrix deposition on tissue samples for matrix-assisted laser desorption/ionization (MALDI) is key for reproducible analyte ion signals. Current methods often result in nonhomogenous matrix deposition, and take time and effort to produce acceptable ion signals. Here we describe a fully-automated method for matrix deposition using an enclosed spray chamber and spray nozzle for matrix solution delivery. A commercial air-atomizing spray nozzle was modified and combined with solenoid controlled valves and a Programmable Logic Controller (PLC) to control and deliver the matrix solution. A spray chamber was employed to contain the nozzle, sample, and atomized matrix solution stream, and to prevent any interference from outside conditions as well as allow complete control of the sample environment. A gravity cup was filled with MALDI matrix solutions, including DHB in chloroform/methanol (50:50) at concentrations up to 60 mg/mL. Various samples (including rat brain tissue sections) were prepared using two deposition methods (spray chamber, inkjet). A linear ion trap equipped with an intermediate-pressure MALDI source was used for analyses. Optical microscopic examination showed a uniform coating of matrix crystals across the sample. Overall, the mass spectral images gathered from tissues coated using the spray chamber system were of better quality and more reproducible than from tissue specimens prepared by the inkjet deposition method.
Structural optical design of the complex multi-group zoom systems by means of matrix optics.
Kryszczyński, T; Mikucki, J
2013-08-26
New matrix formulas for structural optical design have been obtained from analysis of derivative of the system matrix in respect to construction parameters and movements of components. Functional parameters of the optical system become elements of the matrix, presenting working conditions of the optical system. Developed methodology of structural design multi-group zoom systems with unlimited number of components and with mechanical-electronic compensation is presented. Any optical system, such as the objective lens, reproduction system, or telescopic system, can be analyzed with this methodology. Kinematics of components pertaining to a full tract of the zoom system is determined for a discrete number of positions. Three examples of the structural design of complex zoom systems with five-components and high zooming ratio are provided.
Efficient model reduction of parametrized systems by matrix discrete empirical interpolation
NASA Astrophysics Data System (ADS)
Negri, Federico; Manzoni, Andrea; Amsallem, David
2015-12-01
In this work, we apply a Matrix version of the so-called Discrete Empirical Interpolation (MDEIM) for the efficient reduction of nonaffine parametrized systems arising from the discretization of linear partial differential equations. Dealing with affinely parametrized operators is crucial in order to enhance the online solution of reduced-order models (ROMs). However, in many cases such an affine decomposition is not readily available, and must be recovered through (often) intrusive procedures, such as the empirical interpolation method (EIM) and its discrete variant DEIM. In this paper we show that MDEIM represents a very efficient approach to deal with complex physical and geometrical parametrizations in a non-intrusive, efficient and purely algebraic way. We propose different strategies to combine MDEIM with a state approximation resulting either from a reduced basis greedy approach or Proper Orthogonal Decomposition. A posteriori error estimates accounting for the MDEIM error are also developed in the case of parametrized elliptic and parabolic equations. Finally, the capability of MDEIM to generate accurate and efficient ROMs is demonstrated on the solution of two computationally-intensive classes of problems occurring in engineering contexts, namely PDE-constrained shape optimization and parametrized coupled problems.
Antioxidative Properties of Stearoyl Ascorbate in a Food Matrix System.
Wiboonsirikul, Jintana; Watanabe, Yoshiyuki; Omori, Ayako; Khuwijitjaru, Pramote; Adachi, Shuji
2016-06-01
Stearoyl ascorbate or 6-O-stearoyl l-ascorbate is a lipophilic derivative of l-ascorbic acid and is commercially used in foods as a fat-soluble antioxidant and surfactant to overcome the disadvantages of using l-ascorbic acid. The objective of this research is to evaluate the antioxidative ability of stearoyl ascorbate, in the presence of wheat starch or gluten as a matrix, by measuring the unoxidized methyl linoleate available in the mixture of them after oxidation under accelerated conditions compared to that when using ascorbic acid. We observed that stearoyl ascorbate and ascorbic acid exhibited mutually adjacent antioxidative ability against oxidation of the methyl linoleate at a molar ratio of 0.0001 in presence of either wheat starch or gluten. In addition, the oxidation process in the mixture containing either stearoyl ascorbate or ascorbic acid was significantly slower than that in the mixture without stearoyl ascorbate or ascorbic acid. Moreover, by altering the initiation and propagation periods of the oxidation process, the mixture containing the stearoyl ascorbate and gluten as the matrix exhibited conspicuously slower oxidation than the mixture containing either the wheat starch or stearoyl ascorbate alone. However, increase in the ratio of stearoyl ascorbate to methyl linoleate to 0.001 or higher resulted in adverse effects due to acceleration of the oxidation process.
Automated system for fast and accurate analysis of SF6 injected in the surface ocean.
Koo, Chul-Min; Lee, Kitack; Kim, Miok; Kim, Dae-Ok
2005-11-01
This paper describes an automated sampling and analysis system for the shipboard measurement of dissolved sulfur hexafluoride (SF6) in surface marine environments into which SF6 has been deliberately released. This underway system includes a gas chromatograph associated with an electron capture detector, a fast and highly efficient SF6-extraction device, a global positioning system, and a data acquisition system based on Visual Basic 6.0/C 6.0. This work is distinct from previous studies in that it quantifies the efficiency of the SF6-extraction device and its carryover effect and examines the effect of surfactant on the SF6-extraction efficiency. Measurements can be continuously performed on seawater samples taken from a seawater line installed onboard a research vessel. The system runs on an hourly cycle during which one set of four SF6 standards is measured and SF6 derived from the seawater stream is subsequently analyzed for the rest of each 1 h period. This state-of-art system was successfully used to trace a water mass carrying Cochlodinium polykrikoides, which causes harmful algal blooms (HAB) in the coastal waters of southern Korea. The successful application of this analysis system in tracing the HAB-infected water mass suggests that the SF6 detection method described in this paper will improve the quality of the future study of biogeochemical processes in the marine environment.
Hardware and Software Developments for the Accurate Time-Linked Data Acquisition System
BERG,DALE E.; RUMSEY,MARK A.; ZAYAS,JOSE R.
1999-11-09
Wind-energy researchers at Sandia National Laboratories have developed a new, light-weight, modular data acquisition system capable of acquiring long-term, continuous, multi-channel time-series data from operating wind-turbines. New hardware features have been added to this system to make it more flexible and permit programming via telemetry. User-friendly Windows-based software has been developed for programming the hardware and acquiring, storing, analyzing, and archiving the data. This paper briefly reviews the major components of the system, summarizes the recent hardware enhancements and operating experiences, and discusses the features and capabilities of the software programs that have been developed.
NASA Technical Reports Server (NTRS)
Kemp, James Herbert (Inventor); Talukder, Ashit (Inventor); Lambert, James (Inventor); Lam, Raymond (Inventor)
2008-01-01
A computer-implemented system and method of intra-oral analysis for measuring plaque removal is disclosed. The system includes hardware for real-time image acquisition and software to store the acquired images on a patient-by-patient basis. The system implements algorithms to segment teeth of interest from surrounding gum, and uses a real-time image-based morphing procedure to automatically overlay a grid onto each segmented tooth. Pattern recognition methods are used to classify plaque from surrounding gum and enamel, while ignoring glare effects due to the reflection of camera light and ambient light from enamel regions. The system integrates these components into a single software suite with an easy-to-use graphical user interface (GUI) that allows users to do an end-to-end run of a patient record, including tooth segmentation of all teeth, grid morphing of each segmented tooth, and plaque classification of each tooth image.
Accurate BER evaluation for lumped DPSK and OOK systems with PMD and PDL
NASA Astrophysics Data System (ADS)
Zhang, Zhongxi; Chen, Liang; Bao, Xiaoyi
2007-07-01
New forms using Dirac bra-ket notations and their transformations to express electrically filtered currents are presented for optical systems using either binary differential phase-shift keying (2-DPSK) or ON-OFF keying (OOK) with lumped first-order PMD and PDL, arbitrary optical and electrical filtering and pulse shaping. Based on these forms, the moment generating functions (MGFs) and bit-error-ratios (BERs) for different systems are obtained. Our results show that, for a given BER, 2-DPSK requires ~ 5dB lower input signal-to-noise ratio than OOK. By comparing BERs for different polarization systems, we also show that the PDL-induced partially polarized noise can significantly improve system performance and reduce BER variation caused by the random couplings between signal polarization, PDL and PMD vectors.
Simple and accurate empirical absolute volume calibration of a multi-sensor fringe projection system
NASA Astrophysics Data System (ADS)
Gdeisat, Munther; Qudeisat, Mohammad; AlSa`d, Mohammed; Burton, David; Lilley, Francis; Ammous, Marwan M. M.
2016-05-01
This paper suggests a novel absolute empirical calibration method for a multi-sensor fringe projection system. The optical setup of the projector-camera sensor can be arbitrary. The term absolute calibration here means that the centre of the three dimensional coordinates in the resultant calibrated volume coincides with a preset centre to the three-dimensional real-world coordinate system. The use of a zero-phase fringe marking spot is proposed to increase depth calibration accuracy, where the spot centre is determined with sub-pixel accuracy. Also, a new method is proposed for transversal calibration. Depth and transversal calibration methods have been tested using both single sensor and three-sensor fringe projection systems. The standard deviation of the error produced by this system is 0.25 mm. The calibrated volume produced by this method is 400 mm×400 mm×140 mm.
Accurate and portable weigh-in-motion system for manifesting air cargo
NASA Astrophysics Data System (ADS)
Nodine, Robert N.; Scudiere, Matthew B.; Jordan, John K.
1995-12-01
An automated and portable weigh-in-motion system has been developed at Oak Ridge National Laboratory for the purpose of manifesting cargo onto aircraft. The system has an accuracy range of plus or minus 3.0% to plus or minus 6.0% measuring gross vehicle weight and locating the center of balance of moving vehicles at speeds of 1 to 5 mph. This paper reviews the control/user interface system and weight determination algorithm developed to acquire, process, and interpret multiple sensor inputs. The development effort resulted in a self- zeroing, user-friendly system capable of weighing a wide range of vehicles in any random order. The control system is based on the STANDARD (STD) bus and incorporates custom- designed data acquisition and sensor fusion hardware controlled by a personal computer (PC) based single-board computer. The user interface is written in the 'C' language to display number of axles, axle weight, axle spacing, gross weight, and center of balance. The weighing algorithm developed functions with any linear weight sensor and a set of four axle switches per sensor.
Accurate and portable weigh-in-motion system for manifesting air cargo
Nodine, R.N.; Scudiere, M.B.; Jordan, J.K.
1995-12-01
An automated and portable weigh-in-motion system has been developed at Oak Ridge National Laboratory for the purpose of manifesting cargo onto aircraft. The system has an accuracv range of {plus_minus} 3.0% to {plus_minus} 6.0% measuring gross vehicle weight and locating the center of balance of moving vehicles at speeds of 1 to 5 mph. This paper reviews the control/user interface system and weight determination algorithm developed to acquire, process, and interpret multiple sensor inputs. The development effort resulted in a self-zeroing, user-friendly system capable of weighing a wide range of vehicles in any random order. The control system is based on the STANDARD (STD) bus and incorporates custom-designed data acquisition and sensor fusion hardware controlled by a personal computer (PC) based single-board computer. The user interface is written in the ``C`` language to display number of axles, axle weight, axle spacing, gross weight, and center of balance. The weighing algorithm developed will function with any linear weight sensor and a set of four axle switches per sensor.
Accurate prediction of V1 location from cortical folds in a surface coordinate system
Hinds, Oliver P.; Rajendran, Niranjini; Polimeni, Jonathan R.; Augustinack, Jean C.; Wiggins, Graham; Wald, Lawrence L.; Rosas, H. Diana; Potthast, Andreas; Schwartz, Eric L.; Fischl, Bruce
2008-01-01
Previous studies demonstrated substantial variability of the location of primary visual cortex (V1) in stereotaxic coordinates when linear volume-based registration is used to match volumetric image intensities (Amunts et al., 2000). However, other qualitative reports of V1 location (Smith, 1904; Stensaas et al., 1974; Rademacher et al., 1993) suggested a consistent relationship between V1 and the surrounding cortical folds. Here, the relationship between folds and the location of V1 is quantified using surface-based analysis to generate a probabilistic atlas of human V1. High-resolution (about 200 μm) magnetic resonance imaging (MRI) at 7 T of ex vivo human cerebral hemispheres allowed identification of the full area via the stria of Gennari: a myeloarchitectonic feature specific to V1. Separate, whole-brain scans were acquired using MRI at 1.5 T to allow segmentation and mesh reconstruction of the cortical gray matter. For each individual, V1 was manually identified in the high-resolution volume and projected onto the cortical surface. Surface-based intersubject registration (Fischl et al., 1999b) was performed to align the primary cortical folds of individual hemispheres to those of a reference template representing the average folding pattern. An atlas of V1 location was constructed by computing the probability of V1 inclusion for each cortical location in the template space. This probabilistic atlas of V1 exhibits low prediction error compared to previous V1 probabilistic atlases built in volumetric coordinates. The increased predictability observed under surface-based registration suggests that the location of V1 is more accurately predicted by the cortical folds than by the shape of the brain embedded in the volume of the skull. In addition, the high quality of this atlas provides direct evidence that surface-based intersubject registration methods are superior to volume-based methods at superimposing functional areas of cortex, and therefore are better
Sapsis, Themistoklis P; Majda, Andrew J
2013-08-20
A framework for low-order predictive statistical modeling and uncertainty quantification in turbulent dynamical systems is developed here. These reduced-order, modified quasilinear Gaussian (ROMQG) algorithms apply to turbulent dynamical systems in which there is significant linear instability or linear nonnormal dynamics in the unperturbed system and energy-conserving nonlinear interactions that transfer energy from the unstable modes to the stable modes where dissipation occurs, resulting in a statistical steady state; such turbulent dynamical systems are ubiquitous in geophysical and engineering turbulence. The ROMQG method involves constructing a low-order, nonlinear, dynamical system for the mean and covariance statistics in the reduced subspace that has the unperturbed statistics as a stable fixed point and optimally incorporates the indirect effect of non-Gaussian third-order statistics for the unperturbed system in a systematic calibration stage. This calibration procedure is achieved through information involving only the mean and covariance statistics for the unperturbed equilibrium. The performance of the ROMQG algorithm is assessed on two stringent test cases: the 40-mode Lorenz 96 model mimicking midlatitude atmospheric turbulence and two-layer baroclinic models for high-latitude ocean turbulence with over 125,000 degrees of freedom. In the Lorenz 96 model, the ROMQG algorithm with just a single mode captures the transient response to random or deterministic forcing. For the baroclinic ocean turbulence models, the inexpensive ROMQG algorithm with 252 modes, less than 0.2% of the total, captures the nonlinear response of the energy, the heat flux, and even the one-dimensional energy and heat flux spectra.
A Polymer Visualization System with Accurate Heating and Cooling Control and High-Speed Imaging
Wong, Anson; Guo, Yanting; Park, Chul B.; Zhou, Nan Q.
2015-01-01
A visualization system to observe crystal and bubble formation in polymers under high temperature and pressure has been developed. Using this system, polymer can be subjected to a programmable thermal treatment to simulate the process in high pressure differential scanning calorimetry (HPDSC). With a high-temperature/high-pressure view-cell unit, this system enables in situ observation of crystal formation in semi-crystalline polymers to complement thermal analyses with HPDSC. The high-speed recording capability of the camera not only allows detailed recording of crystal formation, it also enables in situ capture of plastic foaming processes with a high temporal resolution. To demonstrate the system’s capability, crystal formation and foaming processes of polypropylene/carbon dioxide systems were examined. It was observed that crystals nucleated and grew into spherulites, and they grew at faster rates as temperature decreased. This observation agrees with the crystallinity measurement obtained with the HPDSC. Cell nucleation first occurred at crystals’ boundaries due to CO2 exclusion from crystal growth fronts. Subsequently, cells were nucleated around the existing ones due to tensile stresses generated in the constrained amorphous regions between networks of crystals. PMID:25915031
2004-09-13
Distributed Systems, 5(8):874–879, August 1994. 154 [109] David Lie, Chandramohan A. Thekkath, Mark Mitchell, Patrick Lincoln, Dan Boneh , John C. Mitchell...Dr. Kai Chang, Dr. James Cross, W. Colby Gibson, Will Hancock, Seth Mason, Dan O’Halloran, Susan Reynolds, Dr. Marllin Simon, and Dr. Tom Smith and
Accurate parameters of the oldest known rocky-exoplanet hosting system: Kepler-10 revisited
Fogtmann-Schulz, Alexandra; Hinrup, Brian; Van Eylen, Vincent; Christensen-Dalsgaard, Jørgen; Kjeldsen, Hans; Silva Aguirre, Víctor; Tingley, Brandon
2014-02-01
Since the discovery of Kepler-10, the system has received considerable interest because it contains a small, rocky planet which orbits the star in less than a day. The system's parameters, announced by the Kepler team and subsequently used in further research, were based on only five months of data. We have reanalyzed this system using the full span of 29 months of Kepler photometric data, and obtained improved information about its star and the planets. A detailed asteroseismic analysis of the extended time series provides a significant improvement on the stellar parameters: not only can we state that Kepler-10 is the oldest known rocky-planet-harboring system at 10.41 ± 1.36 Gyr, but these parameters combined with improved planetary parameters from new transit fits gives us the radius of Kepler-10b to within just 125 km. A new analysis of the full planetary phase curve leads to new estimates on the planetary temperature and albedo, which remain degenerate in the Kepler band. Our modeling suggests that the flux level during the occultation is slightly lower than at the transit wings, which would imply that the nightside of this planet has a non-negligible temperature.
Of Needles and Haystacks: Building an Accurate Statewide Dropout Early Warning System in Wisconsin
ERIC Educational Resources Information Center
Knowles, Jared E.
2015-01-01
The state of Wisconsin has one of the highest four year graduation rates in the nation, but deep disparities among student subgroups remain. To address this the state has created the Wisconsin Dropout Early Warning System (DEWS), a predictive model of student dropout risk for students in grades six through nine. The Wisconsin DEWS is in use…
Control Strategy of a Parallel System Using Both Matrix Converter and Voltage Type Inverter
NASA Astrophysics Data System (ADS)
Itoh, Jun-Ichi; Tamura, Hiroshi
This paper proposes a control strategy for a matrix converter and voltage type inverter in a parallel system that does not require of interconnection reactors. The proposed control strategy is to divide the operation time between a matrix converter and a voltage type inverter. The operation time of each converter is divided in every carrier cycle. As a result, interconnection reactors are not required and the sinusoidal input current waveform of a matrix converter can be obtained. The total output voltage of the proposed system and the output power division ratio for a matrix converter and a voltage type inverter are controlled by the time division ratio of each converter. Furthermore, the voltage error resulting from the operation of time division control was analyzed and compensated. The availability of the proposed system and the validity of the proposed control method are confirmed by experimental results.
A new sensor system for accurate and precise determination of sediment dynamics and position.
NASA Astrophysics Data System (ADS)
Maniatis, Georgios; Hoey, Trevor; Sventek, Joseph; Hodge, Rebecca
2014-05-01
Sediment transport processes control many significant geomorphological changes. Consequently, sediment transport dynamics are studied across a wide range of scales leading to application of a variety of conceptually different mathematical descriptions (models) and data acquisition techniques (sensing). For river sediment transport processes both Eulerian and Lagrangian formulations are used. Data are gathered using a very wide range of sensing techniques that are not always compatible with the conceptual formulation applied. We are concerned with small to medium sediment grain-scale motion in gravel-bed rivers, and other coarse-grained environments, and: a) are developing a customised environmental sensor capable of providing coherent data that reliably record the motion; and, b) provide a mathematical framework in which these data can be analysed and interpreted, this being compatible with current stochastic approaches to sediment transport theory. Here we present results from three different aspects of the above developmental process. Firstly, we present a requirement analysis for the sensor based on the state of the art of the existing technologies. We focus on the factors that enhance data coherence and representativeness, extending the common practice for optimization which is based exclusively on electronics/computing related criteria. This analysis leads to formalization of a method that permits accurate control on the physical properties of the sensor using contemporary rapid prototyping techniques [Maniatis et al. 2013]. Secondly the first results are presented from a series of entrainment experiments in a 5 x 0.8 m flume in which a prototype sensor was deployed to monitor entrainment dynamics under increasing flow conditions (0.037 m3.s-1). The sensor was enclosed in an idealized spherical case (111 mm diameter) and placed on a constructed bed of hemispheres of the same diameter. We measured 3-axial inertial acceleration (as a measure of flow stress
Accurate universal parameterization of absorption cross sections III--light systems
NASA Technical Reports Server (NTRS)
Tripathi, R. K.; Cucinotta, F. A.; Wilson, J. W.
1999-01-01
Our prior nuclear absorption cross sections model [R.K. Tripathi, F.A. Cucinotta, J.W. Wilson, Nucl. Instr. and Meth. B 117 (1996) 347; R.K. Tripathi, J.W. Wilson, F.A. Cucinotta, Nucl. Instr. and Meth. B 129 (1997) 11] is extended for light systems (A < or = 4) where either both projectile and target are light particles or one is light particle and the other is medium or heavy nucleus. The agreement with experiment is excellent for these cases as well. Present work in combination with our original model provides a comprehensive picture of absorption cross sections for light, medium and heavy systems. As a result the extended model can reliably be used in all studies where there is a need for absorption cross sections.
Accurate freezing and melting equations for the Lennard-Jones system.
Khrapak, Sergey A; Morfill, Gregor E
2011-03-07
Analyzing three approximate methods to locate liquid-solid coexistence in simple systems, an observation is made that all of them predict the same functional dependence of the temperature on density at freezing and melting of the conventional Lennard-Jones (LJ) system. The emerging equations can be written as T=Aρ(4)+Bρ(2) in normalized units. We suggest to determine the values of the coefficients A at freezing and melting from the high-temperature limit, governed by the inverse 12th power repulsive potential. The coefficients B can be determined from the triple point parameters of the LJ fluid. This produces freezing and melting equations which are exact in the high-temperature limit and at the triple point and show remarkably good agreement with numerical simulation data in the intermediate region.
Evaluation of a low-cost and accurate ocean temperature logger on subsurface mooring systems
Tian, Chuan; Deng, Zhiqun; Lu, Jun; Xu, Xiaoyang; Zhao, Wei; Xu, Ming
2014-06-23
Monitoring seawater temperature is important to understanding evolving ocean processes. To monitor internal waves or ocean mixing, a large number of temperature loggers are typically mounted on subsurface mooring systems to obtain high-resolution temperature data at different water depths. In this study, we redesigned and evaluated a compact, low-cost, self-contained, high-resolution and high-accuracy ocean temperature logger, TC-1121. The newly designed TC-1121 loggers are smaller, more robust, and their sampling intervals can be automatically changed by indicated events. They have been widely used in many mooring systems to study internal wave and ocean mixing. The logger’s fundamental design, noise analysis, calibration, drift test, and a long-term sea trial are discussed in this paper.
A microbial clock provides an accurate estimate of the postmortem interval in a mouse model system
Metcalf, Jessica L; Wegener Parfrey, Laura; Gonzalez, Antonio; Lauber, Christian L; Knights, Dan; Ackermann, Gail; Humphrey, Gregory C; Gebert, Matthew J; Van Treuren, Will; Berg-Lyons, Donna; Keepers, Kyle; Guo, Yan; Bullard, James; Fierer, Noah; Carter, David O; Knight, Rob
2013-01-01
Establishing the time since death is critical in every death investigation, yet existing techniques are susceptible to a range of errors and biases. For example, forensic entomology is widely used to assess the postmortem interval (PMI), but errors can range from days to months. Microbes may provide a novel method for estimating PMI that avoids many of these limitations. Here we show that postmortem microbial community changes are dramatic, measurable, and repeatable in a mouse model system, allowing PMI to be estimated within approximately 3 days over 48 days. Our results provide a detailed understanding of bacterial and microbial eukaryotic ecology within a decomposing corpse system and suggest that microbial community data can be developed into a forensic tool for estimating PMI. DOI: http://dx.doi.org/10.7554/eLife.01104.001 PMID:24137541
Linear matrix inequalities for analysis and control of linear vector second-order systems
Adegas, Fabiano D.; Stoustrup, Jakob
2014-10-06
Many dynamical systems are modeled as vector second-order differential equations. This paper presents analysis and synthesis conditions in terms of LMI with explicit dependence in the coefficient matrices of vector second-order systems. These conditions benefit from the separation between the Lyapunov matrix and the system matrices by introducing matrix multipliers, which potentially reduce conservativeness in hard control problems. Multipliers facilitate the usage of parameter-dependent Lyapunov functions as certificates of stability of uncertain and time-varying vector second-order systems. The conditions introduced in this work have the potential to increase the practice of analyzing and controlling systems directly in vector second-order form.
Accurate 2D/3D electromagnetic modeling for time-domain airborne EM systems
NASA Astrophysics Data System (ADS)
Yin, C.; Hodges, G.
2012-12-01
The existing industry software cannot deliver correct results for 3D time-domain airborne EM responses. In this paper, starting from the Fourier transform and convolution, we compare the stability of different modeling techniques and analyze the reason for instable calculations of the time-domain airborne EM responses. We find that the singularity of the impulse responses of EM systems at very early time that are used in the convolution is responsible for the instability of the modeling (Fig.1). Based on this finding, we put forward an algorithm that uses step response rather than impulse response of the airborne EM system for the convolution and create a stable algorithm that delivers precise results and maintains well the integral/derivative relationship between the magnetic field B and the magnetic induction dB/dt. A three-step transformation procedure for the modeling is proposed: 1) output the frequency-domain EM response data from the existing software; 2) transform into step-response by digital Fourier/Hankel transform; 3) convolve the step response with the transmitting current or its derivatives. The method has proved to be working very well (Fig. 2). The algorithm can be extended to the modeling of other time-domain ground and airborne EM system responses.Fig. 1: Comparison of impulse and step responses for an airborne EM system Fig. 2: Bz and dBz/dt calculated from step (middle panel) and impulse responses (lower panel) for the same 3D model as in Fig.1.
2011-01-01
Podegracz, Kyle Miller, and Robert Beltran. We are also very grateful for the logistical support received from numerous Navy personnel and contractors...Contam Toxicol. 54(1):44-56. His E, Robert R, and Dinet A, 1989. Combined effects of temperature and salinity on fed and starved larvae of the...system (Lampert et al. in review). The PDMS fibers used in this study were FG 230/210 fibers (Fiber Guide Industries, Stirling , NJ), and had a 210 µm
Toward a highly accurate ambulatory system for clinical gait analysis via UWB radios.
Shaban, Heba A; Abou el-Nasr, Mohamad; Buehrer, R Michael
2010-03-01
In this paper, we propose and investigate a low-cost and low-complexity wireless ambulatory human locomotion tracking system that provides a high ranging accuracy (intersensor distance) suitable for the assessment of clinical gait analysis using wearable ultra wideband (UWB) transceivers. The system design and transceiver performance are presented in additive-white-gaussian noise and realistic channels, using industry accepted channel models for body area networks. The proposed system is theoretically capable of providing a ranging accuracy of 0.11 cm error at distances equivalent to interarker distances, at an 18 dB SNR in realistic on-body UWB channels. Based on real measurements, it provides the target ranging accuracy at an SNR = 20 dB. The achievable accuracy is ten times better than the accuracy reported in the literature for the intermarker-distance measurement. This makes it suitable for use in clinical gait analysis, and for the characterization and assessment of unstable mobility diseases, such as Parkinson's disease.
EZ-Rhizo: integrated software for the fast and accurate measurement of root system architecture.
Armengaud, Patrick; Zambaux, Kevin; Hills, Adrian; Sulpice, Ronan; Pattison, Richard J; Blatt, Michael R; Amtmann, Anna
2009-03-01
The root system is essential for the growth and development of plants. In addition to anchoring the plant in the ground, it is the site of uptake of water and minerals from the soil. Plant root systems show an astonishing plasticity in their architecture, which allows for optimal exploitation of diverse soil structures and conditions. The signalling pathways that enable plants to sense and respond to changes in soil conditions, in particular nutrient supply, are a topic of intensive research, and root system architecture (RSA) is an important and obvious phenotypic output. At present, the quantitative description of RSA is labour intensive and time consuming, even using the currently available software, and the lack of a fast RSA measuring tool hampers forward and quantitative genetics studies. Here, we describe EZ-Rhizo: a Windows-integrated and semi-automated computer program designed to detect and quantify multiple RSA parameters from plants growing on a solid support medium. The method is non-invasive, enabling the user to follow RSA development over time. We have successfully applied EZ-Rhizo to evaluate natural variation in RSA across 23 Arabidopsis thaliana accessions, and have identified new RSA determinants as a basis for future quantitative trait locus (QTL) analysis.
Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera.
Nguyen, Thuy Tuong; Slaughter, David C; Hanson, Bradley D; Barber, Andrew; Freitas, Amy; Robles, Daniel; Whelan, Erin
2015-07-28
This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera) and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration) required to obtain robust performance in a natural outdoor environment. The enumeration system uses a three-step image analysis process based upon: (1) an orthographic plant projection method integrating a perspective transform with automatic parameter estimation; (2) a plant counting method based on projection histograms; and (3) a double-counting avoidance method based on a homography transform. Experimental results demonstrate the ability to count large numbers of plants automatically with no human effort. Results show that, for tree seedlings having a height up to 40 cm and a within-row tree spacing of approximately 10 cm, the algorithms successfully estimated the number of plants with an average accuracy of 95.2% for trees within a single image and 98% for counting of the whole plant population in a large sequence of images.
Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera
Nguyen, Thuy Tuong; Slaughter, David C.; Hanson, Bradley D.; Barber, Andrew; Freitas, Amy; Robles, Daniel; Whelan, Erin
2015-01-01
This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera) and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration) required to obtain robust performance in a natural outdoor environment. The enumeration system uses a three-step image analysis process based upon: (1) an orthographic plant projection method integrating a perspective transform with automatic parameter estimation; (2) a plant counting method based on projection histograms; and (3) a double-counting avoidance method based on a homography transform. Experimental results demonstrate the ability to count large numbers of plants automatically with no human effort. Results show that, for tree seedlings having a height up to 40 cm and a within-row tree spacing of approximately 10 cm, the algorithms successfully estimated the number of plants with an average accuracy of 95.2% for trees within a single image and 98% for counting of the whole plant population in a large sequence of images. PMID:26225982
When do perturbative approaches accurately capture the dynamics of complex quantum systems?
Fruchtman, Amir; Lambert, Neill; Gauger, Erik M.
2016-01-01
Understanding the dynamics of higher-dimensional quantum systems embedded in a complex environment remains a significant theoretical challenge. While several approaches yielding numerically converged solutions exist, these are computationally expensive and often provide only limited physical insight. Here we address the question: when do more intuitive and simpler-to-compute second-order perturbative approaches provide adequate accuracy? We develop a simple analytical criterion and verify its validity for the case of the much-studied FMO dynamics as well as the canonical spin-boson model. PMID:27335176
NIBBS-search for fast and accurate prediction of phenotype-biased metabolic systems.
Schmidt, Matthew C; Rocha, Andrea M; Padmanabhan, Kanchana; Shpanskaya, Yekaterina; Banfield, Jill; Scott, Kathleen; Mihelcic, James R; Samatova, Nagiza F
2012-01-01
Understanding of genotype-phenotype associations is important not only for furthering our knowledge on internal cellular processes, but also essential for providing the foundation necessary for genetic engineering of microorganisms for industrial use (e.g., production of bioenergy or biofuels). However, genotype-phenotype associations alone do not provide enough information to alter an organism's genome to either suppress or exhibit a phenotype. It is important to look at the phenotype-related genes in the context of the genome-scale network to understand how the genes interact with other genes in the organism. Identification of metabolic subsystems involved in the expression of the phenotype is one way of placing the phenotype-related genes in the context of the entire network. A metabolic system refers to a metabolic network subgraph; nodes are compounds and edges labels are the enzymes that catalyze the reaction. The metabolic subsystem could be part of a single metabolic pathway or span parts of multiple pathways. Arguably, comparative genome-scale metabolic network analysis is a promising strategy to identify these phenotype-related metabolic subsystems. Network Instance-Based Biased Subgraph Search (NIBBS) is a graph-theoretic method for genome-scale metabolic network comparative analysis that can identify metabolic systems that are statistically biased toward phenotype-expressing organismal networks. We set up experiments with target phenotypes like hydrogen production, TCA expression, and acid-tolerance. We show via extensive literature search that some of the resulting metabolic subsystems are indeed phenotype-related and formulate hypotheses for other systems in terms of their role in phenotype expression. NIBBS is also orders of magnitude faster than MULE, one of the most efficient maximal frequent subgraph mining algorithms that could be adjusted for this problem. Also, the set of phenotype-biased metabolic systems output by NIBBS comes very close to
Takahashi, F; Shigemori, Y; Seki, A
2009-01-01
A system has been developed to assess radiation dose distribution inside the body of exposed persons in a radiological accident by utilising radiation transport calculation codes-MCNP and MCNPX. The system consists mainly of two parts, pre-processor and post-processor of the radiation transport calculation. Programs for the pre-processor are used to set up a 'problem-dependent' input file, which defines the accident condition and dosimetric quantities to be estimated. The program developed for the post-processor part can effectively indicate dose information based upon the output file of the code. All of the programs in the dosimetry system can be executed with a generally used personal computer and accurately give the dose profile to an exposed person in a radiological accident without complicated procedures. An experiment using a physical phantom was carried out to verify the availability of the dosimetry system with the developed programs in a gamma ray irradiation field.
Structural adjustment for accurate conditioning in large-scale subsurface systems
NASA Astrophysics Data System (ADS)
Tahmasebi, Pejman
2017-03-01
Most of the current subsurface simulation approaches consider a priority list for honoring the well and any other auxiliary data, and eventually adopt a middle ground between the quality of the model and conditioning it to hard data. However, as the number of datasets increases, such methods often produce undesirable features in the subsurface model. Due to their high flexibility, subsurface modeling based on training images (TIs) is becoming popular. Providing comprehensive TIs remains, however, an outstanding problem. In addition, identifying a pattern similar to those in the TI that honors the well and other conditioning data is often difficult. Moreover, the current subsurface modeling approaches do not account for small perturbations that may occur in a subsurface system. Such perturbations are active in most of the depositional systems. In this paper, a new methodology is presented that is based on an irregular gridding scheme that accounts for incomplete TIs and minor offsets. Use of the methodology enables one to use a small or incomplete TI and adaptively change the patterns in the simulation grid in order to simultaneously honor the well data and take into account the effect of the local offsets. Furthermore, the proposed method was used on various complex process-based models and their structures are deformed for matching with the conditioning point data. The accuracy and robustness of the proposed algorithm are successfully demonstrated by applying it to models of several complex examples.
Energy density matrix formalism for interacting quantum systems: a quantum Monte Carlo study
Krogel, Jaron T; Kim, Jeongnim; Reboredo, Fernando A
2014-01-01
We develop an energy density matrix that parallels the one-body reduced density matrix (1RDM) for many-body quantum systems. Just as the density matrix gives access to the number density and occupation numbers, the energy density matrix yields the energy density and orbital occupation energies. The eigenvectors of the matrix provide a natural orbital partitioning of the energy density while the eigenvalues comprise a single particle energy spectrum obeying a total energy sum rule. For mean-field systems the energy density matrix recovers the exact spectrum. When correlation becomes important, the occupation energies resemble quasiparticle energies in some respects. We explore the occupation energy spectrum for the finite 3D homogeneous electron gas in the metallic regime and an isolated oxygen atom with ground state quantum Monte Carlo techniques imple- mented in the QMCPACK simulation code. The occupation energy spectrum for the homogeneous electron gas can be described by an effective mass below the Fermi level. Above the Fermi level evanescent behavior in the occupation energies is observed in similar fashion to the occupation numbers of the 1RDM. A direct comparison with total energy differences demonstrates a quantita- tive connection between the occupation energies and electron addition and removal energies for the electron gas. For the oxygen atom, the association between the ground state occupation energies and particle addition and removal energies becomes only qualitative. The energy density matrix provides a new avenue for describing energetics with quantum Monte Carlo methods which have traditionally been limited to total energies.
Pino, Francisco; Roé, Nuria; Aguiar, Pablo; Falcon, Carles; Ros, Domènec; Pavía, Javier
2015-02-15
Purpose: Single photon emission computed tomography (SPECT) has become an important noninvasive imaging technique in small-animal research. Due to the high resolution required in small-animal SPECT systems, the spatially variant system response needs to be included in the reconstruction algorithm. Accurate modeling of the system response should result in a major improvement in the quality of reconstructed images. The aim of this study was to quantitatively assess the impact that an accurate modeling of spatially variant collimator/detector response has on image-quality parameters, using a low magnification SPECT system equipped with a pinhole collimator and a small gamma camera. Methods: Three methods were used to model the point spread function (PSF). For the first, only the geometrical pinhole aperture was included in the PSF. For the second, the septal penetration through the pinhole collimator was added. In the third method, the measured intrinsic detector response was incorporated. Tomographic spatial resolution was evaluated and contrast, recovery coefficients, contrast-to-noise ratio, and noise were quantified using a custom-built NEMA NU 4–2008 image-quality phantom. Results: A high correlation was found between the experimental data corresponding to intrinsic detector response and the fitted values obtained by means of an asymmetric Gaussian distribution. For all PSF models, resolution improved as the distance from the point source to the center of the field of view increased and when the acquisition radius diminished. An improvement of resolution was observed after a minimum of five iterations when the PSF modeling included more corrections. Contrast, recovery coefficients, and contrast-to-noise ratio were better for the same level of noise in the image when more accurate models were included. Ring-type artifacts were observed when the number of iterations exceeded 12. Conclusions: Accurate modeling of the PSF improves resolution, contrast, and recovery
Wi-GIM system: a new wireless sensor network (WSN) for accurate ground instability monitoring
NASA Astrophysics Data System (ADS)
Mucchi, Lorenzo; Trippi, Federico; Schina, Rosa; Fornaciai, Alessandro; Gigli, Giovanni; Nannipieri, Luca; Favalli, Massimiliano; Marturia Alavedra, Jordi; Intrieri, Emanuele; Agostini, Andrea; Carnevale, Ennio; Bertolini, Giovanni; Pizziolo, Marco; Casagli, Nicola
2016-04-01
Landslides are among the most serious and common geologic hazards around the world. Their impact on human life is expected to increase in the next future as a consequence of human-induced climate change as well as the population growth in proximity of unstable slopes. Therefore, developing better performing technologies for monitoring landslides and providing local authorities with new instruments able to help them in the decision making process, is becoming more and more important. The recent progresses in Information and Communication Technologies (ICT) allow us to extend the use of wireless technologies in landslide monitoring. In particular, the developments in electronics components have permitted to lower the price of the sensors and, at the same time, to actuate more efficient wireless communications. In this work we present a new wireless sensor network (WSN) system, designed and developed for landslide monitoring in the framework of EU Wireless Sensor Network for Ground Instability Monitoring - Wi-GIM project (LIFE12 ENV/IT/001033). We show the preliminary performance of the Wi-GIM system after the first period of monitoring on the active Roncovetro Landslide and on a large subsiding area in the neighbourhood of Sallent village. The Roncovetro landslide is located in the province of Reggio Emilia (Italy) and moved an inferred volume of about 3 million cubic meters. Sallent village is located at the centre of the Catalan evaporitic basin in Spain. The Wi-GIM WSN monitoring system consists of three levels: 1) Master/Gateway level coordinates the WSN and performs data aggregation and local storage; 2) Master/Server level takes care of acquiring and storing data on a remote server; 3) Nodes level that is based on a mesh of peripheral nodes, each consisting in a sensor board equipped with sensors and wireless module. The nodes are located in the landslide ground perimeter and are able to create an ad-hoc WSN. The location of each sensor on the ground is
Stephenson, Megan L; Hawkins, J Seth; Powers, Barbara L; Wing, Deborah A
2014-01-01
Labor induction and cervical ripening are widely utilized and new methods are constantly being investigated. Prostaglandins have been shown to be effective labor induction agents and, in particular, were compared with other prostaglandin preparations; vaginal misoprostol used off-label was associated with reduced failure to achieve vaginal delivery. The challenge is to provide this medication with the correct dosing for this indication and with the ability to discontinue the medication if needed, all while ensuring essential maternal and neonatal safety. The misoprostol vaginal insert initiates cervical ripening using a delivery system that controls misoprostol release and can be rapidly removed. This article reviews the development, safety and efficacy of the misoprostol vaginal insert for induction of labor and cervical ripening, and will focus on vaginally administered prostaglandins.
DRG-based per diem payment system matches costs more accurately.
Brannen, T J
1999-04-01
Some managed care organizations use the DRG hospital payment method developed for Medicare to set case rates. Unfortunately, when such a method is used in a risk-sharing arrangement, hospital and physician incentives are misaligned. Hospitals and payers would benefit from using a hospital reimbursement model that calculates inpatient per diem payments for medical and surgical cases by classifying DRGs in tiers and ranking the tiers according to how resource-intensive they are. DRGs provide the means for a rational classification system of per diem rates that recognizes cases where the expected resources are going to be higher or lower than the average per diem amount. If payers use per diem rates that are weighted according to a DRG classification, hospital payments can correlate closely with the actual costs per day for a specific case, rather than an average for all surgical or medical admissions.
NASA Astrophysics Data System (ADS)
Zabolotna, Natalia I.; Pavlov, Sergii V.; Radchenko, Kostiantyn O.; Stasenko, Vladyslav A.; Wójcik, Waldemar; Kussambayeva, Nazym
2015-12-01
The application field of using the Mueller-matrix polarizing reconstruction system of phase structure of biological layer for optical-anisotropic parameters differentiation of histological sections of healthy and rat's liver with hepatitis were investigated. Comparison of system informativity with known systems on indexes of sensitivity, specificity and balanced accuracy were performed.
How to Compute the Fukui Matrix and Function for Systems with (Quasi-)Degenerate States.
Bultinck, Patrick; Cardenas, Carlos; Fuentealba, Patricio; Johnson, Paul A; Ayers, Paul W
2014-01-14
A system in a spatially (quasi-)degenerate ground state responds in a qualitatively different way to a change in the external potential. Consequently, the usual method for computing the Fukui function, namely, taking the difference between the electron densities of the N- and N ± 1 electron systems, cannot be applied directly. It is shown how the Fukui matrix, and thus also the Fukui function, depends on the nature of the perturbation. One thus needs to use degenerate perturbation theory for the given perturbing potential to generate the density matrix whose change with respect to a change in the number of electrons equals the Fukui matrix. Accounting for the degeneracy in the case of nitrous oxide reveals that an average over the degenerate states differs significantly from using the proper density matrix. We further show the differences in Fukui functions depending on whether a Dirac delta perturbation is used or an interaction with a true point charge (leading to the Fukui potential).
An Accurate Calibration Method Based on Velocity in a Rotational Inertial Navigation System.
Zhang, Qian; Wang, Lei; Liu, Zengjun; Feng, Peide
2015-07-28
Rotation modulation is an effective method to enhance the accuracy of an inertial navigation system (INS) by modulating the gyroscope drifts and accelerometer bias errors into periodically varying components. The typical RINS drives the inertial measurement unit (IMU) rotation along the vertical axis and the horizontal sensors' errors are modulated, however, the azimuth angle error is closely related to vertical gyro drift, and the vertical gyro drift also should be modulated effectively. In this paper, a new rotation strategy in a dual-axis rotational INS (RINS) is proposed and the drifts of three gyros could be modulated, respectively. Experimental results from a real dual-axis RINS demonstrate that the maximum azimuth angle error is decreased from 0.04° to less than 0.01° during 1 h. Most importantly, the changing of rotation strategy leads to some additional errors in the velocity which is unacceptable in a high-precision INS. Then the paper studies the basic reason underlying horizontal velocity errors in detail and a relevant new calibration method is designed. Experimental results show that after calibration and compensation, the fluctuation and stages in the velocity curve disappear and velocity precision is improved.
An Accurate Calibration Method Based on Velocity in a Rotational Inertial Navigation System
Zhang, Qian; Wang, Lei; Liu, Zengjun; Feng, Peide
2015-01-01
Rotation modulation is an effective method to enhance the accuracy of an inertial navigation system (INS) by modulating the gyroscope drifts and accelerometer bias errors into periodically varying components. The typical RINS drives the inertial measurement unit (IMU) rotation along the vertical axis and the horizontal sensors’ errors are modulated, however, the azimuth angle error is closely related to vertical gyro drift, and the vertical gyro drift also should be modulated effectively. In this paper, a new rotation strategy in a dual-axis rotational INS (RINS) is proposed and the drifts of three gyros could be modulated, respectively. Experimental results from a real dual-axis RINS demonstrate that the maximum azimuth angle error is decreased from 0.04° to less than 0.01° during 1 h. Most importantly, the changing of rotation strategy leads to some additional errors in the velocity which is unacceptable in a high-precision INS. Then the paper studies the basic reason underlying horizontal velocity errors in detail and a relevant new calibration method is designed. Experimental results show that after calibration and compensation, the fluctuation and stages in the velocity curve disappear and velocity precision is improved. PMID:26225983
Yatsushiro, Shouki; Yamamoto, Takeki; Yamamura, Shohei; Abe, Kaori; Obana, Eriko; Nogami, Takahiro; Hayashi, Takuya; Sesei, Takashi; Oka, Hiroaki; Okello-Onen, Joseph; Odongo-Aginya, Emmanuel I.; Alai, Mary Auma; Olia, Alex; Anywar, Dennis; Sakurai, Miki; Palacpac, Nirianne MQ; Mita, Toshihiro; Horii, Toshihiro; Baba, Yoshinobu; Kataoka, Masatoshi
2016-01-01
Accurate, sensitive, rapid, and easy operative diagnosis is necessary to prevent the spread of malaria. A cell microarray chip system including a push column for the recovery of erythrocytes and a fluorescence detector was employed for malaria diagnosis in Uganda. The chip with 20,944 microchambers (105 μm width and 50 μm depth) was made of polystyrene. For the analysis, 6 μl of whole blood was employed, and leukocytes were practically removed by filtration through SiO2-nano-fibers in a column. Regular formation of an erythrocyte monolayer in each microchamber was observed following dispersion of an erythrocyte suspension in a nuclear staining dye, SYTO 21, onto the chip surface and washing. About 500,000 erythrocytes were analyzed in a total of 4675 microchambers, and malaria parasite-infected erythrocytes could be detected in 5 min by using the fluorescence detector. The percentage of infected erythrocytes in each of 41 patients was determined. Accurate and quantitative detection of the parasites could be performed. A good correlation between examinations via optical microscopy and by our chip system was demonstrated over the parasitemia range of 0.0039–2.3438% by linear regression analysis (R2 = 0.9945). Thus, we showed the potential of this chip system for the diagnosis of malaria. PMID:27445125
Chaturvedi, Vishal; Dye, Danielle E.; Kinnear, Beverley F.; van Kuppevelt, Toin H.; Grounds, Miranda D.; Coombe, Deirdre R.
2015-01-01
Decellularisation of skeletal muscle provides a system to study the interactions of myoblasts with muscle extracellular matrix (ECM). This study describes the efficient decellularisation of quadriceps muscle with the retention of matrix components and the use of this matrix for myoblast proliferation and differentiation under serum free culture conditions. Three decellularisation approaches were examined; the most effective was phospholipase A2 treatment, which removed cellular material while maximizing the retention of ECM components. Decellularised muscle matrices were then solubilized and used as substrates for C2C12 mouse myoblast serum free cultures. The muscle matrix supported myoblast proliferation and differentiation equally as well as collagen and fibronectin. Immunofluorescence analyses revealed that myoblasts seeded on muscle matrix and fibronectin differentiated to form long, well-aligned myotubes, while myoblasts seeded on collagen were less organized. qPCR analyses showed a time dependent increase in genes involved in skeletal muscle differentiation and suggested that muscle-derived matrix may stimulate an increased rate of differentiation compared to collagen and fibronectin. Decellularized whole muscle three-dimensional scaffolds also supported cell adhesion and spreading, with myoblasts aligning along specific tracts of matrix proteins within the scaffolds. Thus, under serum free conditions, intact acellular muscle matrices provided cues to direct myoblast adhesion and migration. In addition, myoblasts were shown to rapidly secrete and organise their own matrix glycoproteins to create a localized ECM microenvironment. This serum free culture system has revealed that the correct muscle ECM facilitates more rapid cell organisation and differentiation than single matrix glycoprotein substrates. PMID:26030912
Gordon, Brett Ashley; Bruce, Lyndell; Benson, Amanda Clare
2016-08-01
Monitoring physical activity is important to better individualise health and fitness benefits. This study assessed the concurrent validity of a smartphone global positioning system (GPS) 'app' and a sport-specific GPS device with a similar sampling rate, to measure physical activity components of speed and distance, compared to a higher sampling sport-specific GPS device. Thirty-eight (21 female, 17 male) participants, mean age of 24.68, s = 6.46 years, completed two 2.400 km trials around an all-weather athletics track wearing GPSports Pro™ (PRO), GPSports WiSpi™ (WISPI) and an iPhone™ with a Motion X GPS™ 'app' (MOTIONX). Statistical agreement, assessed using t-tests and Bland-Altman plots, indicated an (mean; 95% LOA) underestimation of 2% for average speed (0.126 km·h(-1); -0.389 to 0.642; p < .001), 1.7% for maximal speed (0.442 km·h(-1); -2.676 to 3.561; p = .018) and 1.9% for distance (0.045 km; -0.140 to 0.232; p < .001) by MOTIONX compared to that measured by PRO. In contrast, compared to PRO, WISPI overestimated average speed (0.232 km·h(-1); -0.376 to 0.088; p < .001) and distance (0.083 km; -0.129 to -0.038; p < .001) by 3.5% whilst underestimating maximal speed by 2.5% (0.474 km·h(-1); -1.152 to 2.099; p < .001). Despite the statistically significant difference, the MOTIONX measures intensity of physical activity, with a similar error as WISPI, to an acceptable level for population-based monitoring in unimpeded open-air environments. This presents a low-cost, minimal burden opportunity to remotely monitor physical activity participation to improve the prescription of exercise as medicine.
Hackley, Paul C.
2014-01-01
Vitrinite reflectance generally is considered the most robust thermal maturity parameter available for application to hydrocarbon exploration and petroleum system evaluation. However, until 2011 there was no standardized methodology available to provide guidelines for vitrinite reflectance measurements in shale. Efforts to correct this deficiency resulted in publication of ASTM D7708-11: Standard test method for microscopical determination of the reflectance of vitrinite dispersed in sedimentary rocks. In 2012-2013, an interlaboratory exercise was conducted to establish precision limits for the measurement technique. Six samples, representing a wide variety of shale, were tested in duplicate by 28 analysts in 22 laboratories from 14 countries. Samples ranged from immature to overmature (Ro 0.31-1.53%), from organic-rich to organic-lean (1-22 wt.% total organic carbon), and contained Type I (lacustrine), Type II (marine), and Type III (terrestrial) kerogens. Repeatability values (difference between repetitive results from same operator, same conditions) ranged from 0.03-0.11% absolute reflectance, whereas reproducibility values (difference between results obtained on same test material by different operators, different laboratories) ranged from 0.12-0.54% absolute reflectance. Repeatability and reproducibility degraded consistently with increasing maturity and decreasing organic content. However, samples with terrestrial kerogens (Type III) fell off this trend, showing improved levels of reproducibility due to higher vitrinite content and improved ease of identification. Operators did not consistently meet the reporting requirements of the test method, indicating that a common reporting template is required to improve data quality. The most difficult problem encountered was the petrographic distinction of solid bitumens and low-reflecting inert macerals from vitrinite when vitrinite occurred with reflectance ranges overlapping the other components. Discussion among
Calcium alginate gel as encapsulation matrix for coimmobilized enzyme systems.
Blandino, A; Macías, M; Cantero, D
2003-07-01
Encapsulation within calcium alginate gel capsules was used to produce a coimmobilized enzyme system. Glucose oxidase (GOD) and catalase (CAT) were chosen as model enzymes. The same values of Vmax and Km app for the GOD encapsulated system and for the GOD-CAT coencapsulated system were calculated. When gel beads and capsules were compared, the same catalyst deactivation sequence for the two enzymes was observed. However, when capsules were employed as immobilization support, GOD efficiencies were higher than for the gel beads. These results were explained in terms of the structure of the capsules.
Hessian matrix estimation in hybrid systems based on an embedded FFNN.
Baek, Seung-Mook; Park, Jung-Wook
2010-10-01
This paper describes the Hessian matrix estimation of nonsmooth nonlinear parameters by the identifier based on a feedforward neural network (FFNN) embedded in a hybrid system, which is modeled by the differential-algebraic-impulsive-switched (DAIS) structure. After identifying full dynamics of the hybrid system, the FFNN is used to estimate second-order derivatives of an objective function J with respect to the nonlinear parameters from the gradient information, which are trajectory sensitivities. Then, the estimated Hessian matrix is applied to the optimal tuning of a saturation limiter used in a practical engineering system.
Evaluation of microwave digestion systems for mercury recovery in an oil matrix
Whitaker, M.J.; Clymire, J.W.
1997-09-01
The scope of this document is to characterize three microwave systems developed by CEM Corporation. The purpose of this investigative work was to evaluate the performance of each system for dissolution qualities and the recovery of mercury in an oil based matrix. The microwave systems evaluated were the heavy duty vessel system (HDV), the advanced composite system (ACV), and the open vessel system (OVS). All three systems have automated features, but all systems are limited by one factor or another. EPA method 3051 was the procedure used for sample preparation for this project. This particular microwave digestion method can also be used for other metal analytes of interest. Of the three different systems, only the HDV (now UDV) demonstrated complete digestion of the oil based matrix in a one step process and acceptable mercury recoveries.
Wang, Siwei; Sun, Dongning; Dong, Yi; Xie, Weilin; Shi, Hongxiao; Yi, Lilin; Hu, Weisheng
2014-02-15
We have developed a radio-frequency local oscillator remote distribution system, which transfers a phase-stabilized 10.03 GHz signal over 100 km optical fiber. The phase noise of the remote signal caused by temperature and mechanical stress variations on the fiber is compensated by a high-precision phase-correction system, which is achieved using a single sideband modulator to transfer the phase correction from intermediate frequency to radio frequency, thus enabling accurate phase control of the 10 GHz signal. The residual phase noise of the remote 10.03 GHz signal is measured to be -70 dBc/Hz at 1 Hz offset, and long-term stability of less than 1×10⁻¹⁶ at 10,000 s averaging time is achieved. Phase error is less than ±0.03π.
Lockwood, R.E.; Blankinship, D.R.
1994-12-31
Environmental monitoring programs often require accurate determination of sampling site locations in aquatic environments. This is especially true when a {open_quotes}picture{close_quotes} of high resolution is needed for observing a changing variable in a given area and location is assumed to be important to the distribution of that variable. Sample site location can be difficult if few visible land marks are available for reference on a large body of water. The use of navigational systems such as Global Positioning System (GPS) and its predecessor, Loran-C, provide an excellent method for sample site location. McFarland (1992) discusses the practicality of GPS for location determination. This article discusses the use of Loran-C in a sampling scheme implemented at the South Texas Project Electrical Generating Station (STPEGS), Wadsworth, Texas.
Computing the Moore-Penrose Inverse of a Matrix with a Computer Algebra System
ERIC Educational Resources Information Center
Schmidt, Karsten
2008-01-01
In this paper "Derive" functions are provided for the computation of the Moore-Penrose inverse of a matrix, as well as for solving systems of linear equations by means of the Moore-Penrose inverse. Making it possible to compute the Moore-Penrose inverse easily with one of the most commonly used Computer Algebra Systems--and to have the blueprint…
Problems in hypercomplex analysis over some matrix hypercomplex systems
NASA Astrophysics Data System (ADS)
Apostolova, Lilia N.; Dimiev, Stancho; Marinov, Marin S.; Stoev, Peter
2011-12-01
In this paper the authors emphasize first on the holomorphy and power series analyticity over the non-division algebra C(1,j) of double-complex number z+jw, j4 = -1, (or j2 = i,) z,w∈ C, j∉C, and it real cyclic hypercomplex 4-dimensional system R(1,j,j2,j3). For general algebra with zero divisors (or hypercomplex number system of finite dimension n+1) we are interested of the stratification of the underline n-dimensional multiplicative ring system (in fact Rn) consisting of all simply connected open subsets of invertible elements. These subsets are called regular components of the mentioned stratification, contrary to the subset of non-invertible elements called singular. It is to remark that the classical complex analysis is based on the simplest stratification consisting of one strata only—the subset of regular elements C∗C {0}. But the function theory over the algebra of the hyperbolic complex numbers (the double-numbers) is based on 4 different simply connected subsets (4 regular strata). On each such strata one can develop a kind of complex analysis, but if z is singular element, i.e. non-invertible, one cannot define near to z0 a Loran series for instance. The problem of finding the concrete stratification for a given non-division algebra seems to be important. Some other problems, more or less of technical character are formulated too.
NASA Astrophysics Data System (ADS)
Malli, G. L.; Da Silva, A. B. F.; Ishikawa, Yasuyuki
1994-10-01
A universal Gaussian basis set is developed that leads to relativistic Dirac-Fock SCF energies of comparable accuracy as that obtained by the accurate numerical finite-difference method (GRASP2 package) [J. Phys. B 25, 1 (1992)]. The Gaussian-type functions of our universal basis set satisfy the relativistic boundary conditions associated with the finite nuclear model for a finite speed of light and conform to the so-called kinetic balance at the nonrelativistic limit. We attribute the exceptionally high accuracy obtained in our calculations to the fact that the representation of the relativistic dynamics of an electron in a spherical ball finite nucleus near the origin in terms of our universal Gaussian basis set is as accurate as that provided by the numerical finite-difference method. Results of the Dirac-Fock-Coulomb energies for a number of atoms up to No (Z=102) and some negative ions are presented and compared with the recent results obtained with the numerical finite-difference method and geometrical Gaussian basis sets by Parpia, Mohanty, and Clementi [J. Phys. B 25, 1 (1992)]. The accuracy of our calculations is estimated to be within a few parts in 109 for all the atomic systems studied.
NASA Astrophysics Data System (ADS)
Yi, Sha-Sha; Pan, Cong; Hu, Zhong-Han
2015-12-01
Modern computer simulations of biological systems often involve an explicit treatment of the complex interactions among a large number of molecules. While it is straightforward to compute the short-ranged Van der Waals interaction in classical molecular dynamics simulations, it has been a long-lasting issue to develop accurate methods for the longranged Coulomb interaction. In this short review, we discuss three types of methodologies for the accurate treatment of electrostatics in simulations of explicit molecules: truncation-type methods, Ewald-type methods, and mean-field-type methods. Throughout the discussion, we brief the formulations and developments of these methods, emphasize the intrinsic connections among the three types of methods, and focus on the existing problems which are often associated with the boundary conditions of electrostatics. This brief survey is summarized with a short perspective on future trends along the method developments and applications in the field of biological simulations. Project supported by the National Natural Science Foundation of China (Grant Nos. 91127015 and 21522304) and the Open Project from the State Key Laboratory of Theoretical Physics, and the Innovation Project from the State Key Laboratory of Supramolecular Structure and Materials.
Cotte, F.P.; Doughty, C.; Birkholzer, J.
2010-11-01
The ability to reliably predict flow and transport in fractured porous rock is an essential condition for performance evaluation of geologic (underground) nuclear waste repositories. In this report, a suite of programs (TRIPOLY code) for calculating and analyzing flow and transport in two-dimensional fracture-matrix systems is used to model single-well injection-withdrawal (SWIW) tracer tests. The SWIW test, a tracer test using one well, is proposed as a useful means of collecting data for site characterization, as well as estimating parameters relevant to tracer diffusion and sorption. After some specific code adaptations, we numerically generated a complex fracture-matrix system for computation of steady-state flow and tracer advection and dispersion in the fracture network, along with solute exchange processes between the fractures and the porous matrix. We then conducted simulations for a hypothetical but workable SWIW test design and completed parameter sensitivity studies on three physical parameters of the rock matrix - namely porosity, diffusion coefficient, and retardation coefficient - in order to investigate their impact on the fracture-matrix solute exchange process. Hydraulic fracturing, or hydrofracking, is also modeled in this study, in two different ways: (1) by increasing the hydraulic aperture for flow in existing fractures and (2) by adding a new set of fractures to the field. The results of all these different tests are analyzed by studying the population of matrix blocks, the tracer spatial distribution, and the breakthrough curves (BTCs) obtained, while performing mass-balance checks and being careful to avoid some numerical mistakes that could occur. This study clearly demonstrates the importance of matrix effects in the solute transport process, with the sensitivity studies illustrating the increased importance of the matrix in providing a retardation mechanism for radionuclides as matrix porosity, diffusion coefficient, or retardation
Double β-decay nuclear matrix elements for the A=48 and A=58 systems
NASA Astrophysics Data System (ADS)
Skouras, L. D.; Vergados, J. D.
1983-11-01
The nuclear matrix elements entering the double β decays of the 48Ca-48Ti and 58Ni-58Fe systems have been calculated using a realistic two nucleon interaction and realistic shell model spaces. Effective transition operators corresponding to a variety of gauge theory models have been considered. The stability of such matrix elements against variations of the nuclear parameters is examined. Appropriate lepton violating parameters are extracted from the A=48 data and predictions are made for the lifetimes of the positron decays of the A=58 system. RADIOACTIVITY Double β decay. Gauge theories. Lepton nonconservation. Neutrino mass. Shell model calculations.
Snorradóttir, Bergthóra S; Jónsdóttir, Fjóla; Sigurdsson, Sven Th; Másson, Már
2014-08-01
A model is presented for transdermal drug delivery from single-layered silicone matrix systems. The work is based on our previous results that, in particular, extend the well-known Higuchi model. Recently, we have introduced a numerical transient model describing matrix systems where the drug dissolution can be non-instantaneous. Furthermore, our model can describe complex interactions within a multi-layered matrix and the matrix to skin boundary. The power of the modelling approach presented here is further illustrated by allowing the possibility of a donor solution. The model is validated by a comparison with experimental data, as well as validating the parameter values against each other, using various configurations with donor solution, silicone matrix and skin. Our results show that the model is a good approximation to real multi-layered delivery systems. The model offers the ability of comparing drug release for ibuprofen and diclofenac, which cannot be analysed by the Higuchi model because the dissolution in the latter case turns out to be limited. The experiments and numerical model outlined in this study could also be adjusted to more general formulations, which enhances the utility of the numerical model as a design tool for the development of drug-loaded matrices for trans-membrane and transdermal delivery.
Yao, Rutao; Ramachandra, Ranjith M.; Mahajan, Neeraj; Rathod, Vinay; Gunasekar, Noel; Panse, Ashish; Ma, Tianyu; Jian, Yiqiang; Yan, Jianhua; Carson, Richard E.
2012-01-01
To achieve optimal PET image reconstruction through better system modeling, we developed a system matrix that is based on the probability density function for each line of response (LOR-PDF). The LOR-PDFs are grouped by LOR-to-detector incident angles to form a highly compact system matrix. The system matrix was implemented in the MOLAR list mode reconstruction algorithm for a small animal PET scanner. The impact of LOR-PDF on reconstructed image quality was assessed qualitatively as well as quantitatively in terms of contrast recovery coefficient (CRC) and coefficient of variance (COV), and its performance was compared with a fixed Gaussian (iso-Gaussian) line spread function. The LOR-PDFs of 3 coincidence signal emitting sources, 1) ideal positron emitter that emits perfect back-to-back γ rays (γγ) in air; 2) fluorine-18 (18F) nuclide in water; and 3) oxygen-15 (15O) nuclide in water, were derived, and assessed with simulated and experimental phantom data. The derived LOR-PDFs showed anisotropic and asymmetric characteristics dependent on LOR-detector angle, coincidence emitting source, and the medium, consistent with common PET physical principles. The comparison of the iso-Gaussian function and LOR-PDF showed that: 1) without positron range and acolinearity effects, the LOR-PDF achieved better or similar trade-offs of contrast recovery and noise for objects of 4-mm radius or larger, and this advantage extended to smaller objects (e.g. 2-mm radius sphere, 0.6-mm radius hot-rods) at higher iteration numbers; and 2) with positron range and acolinearity effects, the iso-Gaussian achieved similar or better resolution recovery depending on the significance of positron range effect. We conclude that the 3-D LOR-PDF approach is an effective method to generate an accurate and compact system matrix. However, when used directly in expectation-maximization based list-mode iterative reconstruction algorithms such as MOLAR, its superiority is not clear. For this
NASA Astrophysics Data System (ADS)
Gao, Pengzhi; Wang, Meng; Chow, Joe H.; Ghiocel, Scott G.; Fardanesh, Bruce; Stefopoulos, George; Razanousky, Michael P.
2016-11-01
This paper presents a new framework of identifying a series of cyber data attacks on power system synchrophasor measurements. We focus on detecting "unobservable" cyber data attacks that cannot be detected by any existing method that purely relies on measurements received at one time instant. Leveraging the approximate low-rank property of phasor measurement unit (PMU) data, we formulate the identification problem of successive unobservable cyber attacks as a matrix decomposition problem of a low-rank matrix plus a transformed column-sparse matrix. We propose a convex-optimization-based method and provide its theoretical guarantee in the data identification. Numerical experiments on actual PMU data from the Central New York power system and synthetic data are conducted to verify the effectiveness of the proposed method.
Non-stochastic matrix Schrödinger equation for open systems
NASA Astrophysics Data System (ADS)
Joubert-Doriol, Loïc; Ryabinkin, Ilya G.; Izmaylov, Artur F.
2014-12-01
We propose an extension of the Schrödinger equation for a quantum system interacting with environment. This extension describes dynamics of a collection of auxiliary wavefunctions organized as a matrix m, from which the system density matrix can be reconstructed as hat{ρ }= {m} {m}^dagger. We formulate a compatibility condition, which ensures that the reconstructed density satisfies a given quantum master equation for the system density. The resulting non-stochastic evolution equation preserves positive-definiteness of the system density and is applicable to both Markovian and non-Markovian system-bath treatments. Our formalism also resolves a long-standing problem of energy loss in the time-dependent variational principle applied to mixed states of closed systems.
On the equilibrium state of a small system with random matrix coupling to its environment
NASA Astrophysics Data System (ADS)
Lebowitz, J. L.; Pastur, L.
2015-07-01
We consider a random matrix model of interaction between a small n-level system, S, and its environment, a N-level heat reservoir, R. The interaction between S and R is modeled by a tensor product of a fixed n× n matrix and a N× N Hermitian random matrix. We show that under certain ‘macroscopicity’ conditions on R, the reduced density matrix of the system {{ρ }S}=T{{r}R}ρ S\\cup R(eq), is given by ρ S(c)˜ exp \\{-β {{H}S}\\}, where HS is the Hamiltonian of the isolated system. This holds for all strengths of the interaction and thus gives some justification for using ρ S(c) to describe some nano-systems, like biopolymers, in equilibrium with their environment (Seifert 2012 Rep. Prog. Phys. 75 126001). Our results extend those obtained previously in (Lebowitz and Pastur 2004 J. Phys. A: Math. Gen. 37 1517-34) (Lebowitz et al 2007 Contemporary Mathematics (Providence RI: American Mathematical Society) pp 199-218) for a special two-level system.
Testing the Predictions of Random Matrix Theory in Low Loss Wave Chaotic Scattering Systems
NASA Astrophysics Data System (ADS)
Yeh, Jen-Hao; Antonsen, Thomas; Ott, Edward; Anlage, Steven
2013-03-01
Wave chaos is a field where researchers apply random matrix theory (RMT) to predict the statistics of wave properties in complicated wave scattering systems. The RMT predictions have successfully demonstrated universality of the distributions of these wave properties, which only depend on the loss parameter of the system and the physical symmetry. Examination of these predictions in very low loss systems is interesting because extreme limits for the distribution functions and other predictions are encountered. Therefore, we use a wave-chaotic superconducting cavity to establish a low loss environment and test RMT predictions, including the statistics of the scattering (S) matrix and the impedance (Z) matrix, the universality (or lack thereof) of the Z- and S-variance ratios, and the statistics of the proper delay times of the Wigner-Smith time-delay matrix. We have applied an in-situ microwave calibration method (Thru-Reflection-Line method) to calibrate the cryostat system, and we also applied the random coupling model to remove the system-specific features. Our experimental results of different properties agree with the RMT predictions. This work is funded by the ONR/Maryland AppEl Center Task A2 (contract No. N000140911190), the AFOSR under grant FA95500710049, and Center for Nanophysics and Advanced Materials.
NASA Astrophysics Data System (ADS)
Cotte, F.; Doughty, C.; Birkholzer, J. T.
2010-12-01
An essential condition for performance evaluation of enhanced geothermal systems (EGS) resides in the ability to reliably predict fluid flow and heat transport in fractured porous rocks, where fast convection-dispersive transport through the fracture network can be strongly affected by heat conduction into the adjacent rock matrix. SWIW tests are single-well tracer tests that involve an initial period of fluid and tracer injection followed by a period of fluid withdrawal. As a result of the flow field reversal, the measured breakthrough curves tend to be less sensitive to advective heterogeneities and more sensitive to matrix diffusion and sorption, making this method very valuable in characterizing fracture-matrix interaction and evaluating matrix properties. In particular, we propose using SWIW tests before and after hydrofracking operations, to help assess the means by which hydrofracking increases permeability and enhances fracture-matrix interaction. In the present study, we have modeled single-well injection-withdrawal (SWIW) tests for non-sorbing and sorbing tracers, using the mixed Eulerian-Lagrangian transport simulator TRIPOLY, which solves tracer advection and dispersion in fracture networks together with solute exchange processes between the fractures and the porous matrix. Our simulations were conducted for hypothetical but workable SWIW test designs considering a variety of statistically generated 2D fracture-matrix systems. Parameter sensitivity studies were completed on three physical parameters of the rock matrix, namely porosity, diffusion coefficient and retardation coefficient, in order to investigate their impact on the fracture-matrix solute exchange process. Hydraulic fracturing, or hydrofracking, was modeled in two different ways, one by increasing the fracture aperture for flow and the other one by adding a new set of fractures to the fracture network. The results of all these different tests were analyzed by studying the population of
NASA Astrophysics Data System (ADS)
An, Zhe; Rey, Daniel; Ye, Jingxin; Abarbanel, Henry D. I.
2017-01-01
The problem of forecasting the behavior of a complex dynamical system through analysis of observational time-series data becomes difficult when the system expresses chaotic behavior and the measurements are sparse, in both space and/or time. Despite the fact that this situation is quite typical across many fields, including numerical weather prediction, the issue of whether the available observations are "sufficient" for generating successful forecasts is still not well understood. An analysis by Whartenby et al. (2013) found that in the context of the nonlinear shallow water equations on a β plane, standard nudging techniques require observing approximately 70 % of the full set of state variables. Here we examine the same system using a method introduced by Rey et al. (2014a), which generalizes standard nudging methods to utilize time delayed measurements. We show that in certain circumstances, it provides a sizable reduction in the number of observations required to construct accurate estimates and high-quality predictions. In particular, we find that this estimate of 70 % can be reduced to about 33 % using time delays, and even further if Lagrangian drifter locations are also used as measurements.
Lu, Zhilei; Chen, Weiyang; Hamman, Josias H; Ni, Jian; Zhai, Xiaoling
2008-01-01
The in vitro performance of monolithic matrix systems containing the interpolyelectrolyte complex between chitosan and polycarbophil as excipient was evaluated in terms of their swelling, bioadhesive, and drug release properties. The different matrix systems showed excellent swelling properties without erosion, except for the formulation containing the highest quantity chitosan-polycarbophil complex that exhibited surface erosion in addition to swelling. All the different matrix systems exhibited significantly higher bioadhesive properties than the control group. Furthermore, they showed controlled insulin release without an initial burst release effect. However, only the matrix system that exhibited surface erosion in combination with swelling approached zero-order release.
Integrating random matrix theory predictions with short-time dynamical effects in chaotic systems.
Smith, A Matthew; Kaplan, Lev
2010-07-01
We discuss a modification to random matrix theory eigenstate statistics that systematically takes into account the nonuniversal short-time behavior of chaotic systems. The method avoids diagonalization of the Hamiltonian; instead it requires only knowledge of short-time dynamics for a chaotic system or ensemble of similar systems. Standard random matrix theory and semiclassical predictions are recovered in the limits of zero Ehrenfest time and infinite Heisenberg time, respectively. As examples, we discuss wave-function autocorrelations and cross correlations, and show that significant improvement in accuracy is obtained for simple chaotic systems where comparison can be made with brute-force diagonalization. The accuracy of the method persists even when the short-time dynamics of the system or ensemble is known only in a classical approximation. Further improvement in the rate of convergence is obtained when the method is combined with the correlation function bootstrapping approach introduced previously.
The impact of system matrix dimension on small FOV SPECT reconstruction with truncated projections
Chan, Chung E-mail: Chi.Liu@yale.edu; Wu, Jing; Liu, Chi E-mail: Chi.Liu@yale.edu; Dey, Joyoni; Grobshtein, Yariv; Liu, Yi-Hwa; Lampert, Rachel; Sinusas, Albert J.
2016-01-15
Purpose: A dedicated cardiac hybrid single photon emission computed tomography (SPECT)/CT scanner that uses cadmium zinc telluride detectors and multiple pinhole collimators for stationary acquisition offers many advantages. However, the impact of the reconstruction system matrix (SM) dimension on the reconstructed image quality from truncated projections and 19 angular samples acquired on this scanner has not been extensively investigated. In this study, the authors aimed to investigate the impact of the dimensions of SM and the use of body contour derived from adjunctive CT imaging as an object support in reconstruction on this scanner, in relation to background extracardiac activity. Methods: The authors first simulated a generic SPECT/CT system to image four NCAT phantoms with various levels of extracardiac activity and compared the reconstructions using SM in different dimensions and with/without body contour as a support for quantitative evaluations. The authors then compared the reconstructions of 18 patient studies, which were acquired on a GE Discovery NM570c scanner following injection of different radiotracers, including {sup 99m}Tc-Tetrofosmin and {sup 123}I-mIBG, comparing the scanner’s default SM that incompletely covers the body with a large SM that incorporates a patient specific full body contour. Results: The simulation studies showed that the reconstructions using a SM that only partially covers the body yielded artifacts on the edge of the field of view (FOV), overestimation of activity and increased nonuniformity in the blood pool for the phantoms with higher relative levels of extracardiac activity. However, the impact on the quantitative accuracy in the high activity region, such as the myocardium, was subtle. On the other hand, an excessively large SM that enclosed the entire body alleviated the artifacts and reduced overestimation in the blood pool, but yielded slight underestimation in myocardium and defect regions. The reconstruction
Vitamins E and C - effects on matrix components in the vascular system
Technology Transfer Automated Retrieval System (TEKTRAN)
The connective tissue in the vascular system, consisting mainly of vascular smooth muscle cells (VSMC) and the interstitial extracellular matrix (ECM), plays important roles in the maintenance of an intact vascular wall as well as in the repair of atherosclerotic lesions during disease development. ...
Linear System of Equations, Matrix Inversion, and Linear Programming Using MS Excel
ERIC Educational Resources Information Center
El-Gebeily, M.; Yushau, B.
2008-01-01
In this note, we demonstrate with illustrations two different ways that MS Excel can be used to solve Linear Systems of Equation, Linear Programming Problems, and Matrix Inversion Problems. The advantage of using MS Excel is its availability and transparency (the user is responsible for most of the details of how a problem is solved). Further, we…
Chitosan-polycarbophil complexes in swellable matrix systems for controlled drug release.
Lu, Z; Chen, W; Hamman, J H
2007-10-01
A prerequisite for progress in the design of novel drug delivery systems is the development of excipients that are capable of fulfilling multifunctional roles such as controlling the release of the drug according to the therapeutic needs. Although several polymers have been utilised in the development of specialised drug delivery systems, their scope in dosage form design can be enlarged through combining different polymers. When a polymer is cross-linked or complexed with an oppositely charged polyelectrolyte, a three-dimensional network is formed in which the drug can be incorporated to control its release. The swelling properties and release kinetics of two model drugs with different water solubilities (i.e. diltiazem and ibuprofen) from monolithic matrix tablets consisting of an interpolyelectrolyte complex between chitosan and polycarbophil are reported. Matrix tablets consisting of this polymeric complex without drug or excipients exhibited extremely high swelling properties that are completely reversible upon drying. The drug release from matrix systems with different formulations depended on the concentration of the chitosan-polycarbophil interpolyelectrolyte complex and approached zero order release kinetics for both model drugs. The chitosan-polycarbophil interpolyelectrolyte complex has demonstrated a high potential as an excipient for the production of swellable matrix systems with controlled drug release properties.
Drug Release from Inert Spherical Matrix Systems Using Monte Carlo Simulations.
Villalobos, Rafael; Garcia, Erika V; Quintanar, David; Young, Paul M
2016-05-12
The objective of this research is to study the behavior of drug delivery from inert spherical matrix systems of different size by means of computer simulation. To simulate the matrix medium, a simple cubic lattice was used, which was sectioned to make a spherical macroscopic system. The sites within the system were randomly occupied by drug-particles or excipient-particles in accordance with chosen drug/excipient ratios. Then, the drug was released from the matrix system simulating a diffusion process. It was found that the release from these systems over short time scales is properly described by the power equation. When the released fraction was processed until 90% release, the Weibull equation suitably expressed the release profiles. On the basis of the analysis of the previous model equations, it was found that close to the percolation threshold an anomalous released occurs, while in the systems with an initial drug load greater than 0.45, the released was Fickian type. Through computer simulation, it was also possible to determine the amount of drug trapped in the matrix, which was found to be a function of the initial drug load. The relationship between the two mentioned variables was adequately described by a model that involves the error function. Based on the results obtained from the amount of drug trapped according to initial drug load and by means of a non-linear regression to the previous model, it was possible to determine the drug percolation threshold in these matrix devices. It was found that the percolation threshold is consistent with the value predicted by the percolation theory.
Nazareth, D; Malhotra, H; French, S; Hoffmann, K; Merrow, C
2014-06-01
Purpose: Breast radiotherapy, particularly electronic compensation, may involve large dose gradients and difficult patient positioning problems. We have developed a simple self-calibrating augmented-reality system, which assists in accurately and reproducibly positioning the patient, by displaying her live image from a single camera superimposed on the correct perspective projection of her 3D CT data. Our method requires only a standard digital camera capable of live-view mode, installed in the treatment suite at an approximately-known orientation and position (rotation R; translation T). Methods: A 10-sphere calibration jig was constructed and CT imaged to provide a 3D model. The (R,T) relating the camera to the CT coordinate system were determined by acquiring a photograph of the jig and optimizing an objective function, which compares the true image points to points calculated with a given candidate R and T geometry. Using this geometric information, 3D CT patient data, viewed from the camera's perspective, is plotted using a Matlab routine. This image data is superimposed onto the real-time patient image, acquired by the camera, and displayed using standard live-view software. This enables the therapists to view both the patient's current and desired positions, and guide the patient into assuming the correct position. The method was evaluated using an in-house developed bolus-like breast phantom, mounted on a supporting platform, which could be tilted at various angles to simulate treatment-like geometries. Results: Our system allowed breast phantom alignment, with an accuracy of about 0.5 cm and 1 ± 0.5 degree. Better resolution could be possible using a camera with higher-zoom capabilities. Conclusion: We have developed an augmented-reality system, which combines a perspective projection of a CT image with a patient's real-time optical image. This system has the potential to improve patient setup accuracy during breast radiotherapy, and could possibly be
NASA Astrophysics Data System (ADS)
Iorio, L.
2016-01-01
By using the most recently published Doppler tomography measurements and accurate theoretical modelling of the oblateness-driven orbital precessions, we tightly constrain some of the physical and orbital parameters of the planetary system hosted by the fast rotating star WASP-33. In particular, the measurements of the orbital inclination ip to the plane of the sky and of the sky-projected spin-orbit misalignment λ at two epochs about six years apart allowed for the determination of the longitude of the ascending node Ω and of the orbital inclination I to the apparent equatorial plane at the same epochs. As a consequence, average rates of change dot{Ω }_exp, dot{I}_exp of this two orbital elements, accurate to a ≈10-2 deg yr-1 level, were calculated as well. By comparing them to general theoretical expressions dot{Ω }_{J_2}, dot{I}_{J_2} for their precessions induced by an oblate star whose symmetry axis is arbitrarily oriented, we were able to determine the angle i⋆ between the line of sight the star's spin {S}^{star } and its first even zonal harmonic J_2^{star } obtaining i^{star } = {142}^{+10}_{-11} deg, J_2^{star } = 2.1^{+0.8}_{-0.5}times; 10^{-4}. As a by-product, the angle between {S}^{star } and the orbital angular momentum L is as large as about ψ ≈ 100 ° psi; ^{2008} = 99^{+5}_{-4} deg, ψ ^{{2014}} = 103^{+5}_{-4} deg and changes at a rate dot{ψ }= 0.{7}^{+1.5}_{-1.6} deg {yr}^{-1}. The predicted general relativistic Lense-Thirring precessions, of the order of ≈10-3deg yr-1, are, at present, about one order of magnitude below the measurability threshold.
Luo, Xiongbiao
2014-06-15
electromagnetically navigated bronchoscopy system was constructed with accurate registration of an electromagnetic tracker and the CT volume on the basis of an improved marker-free registration approach that uses the bronchial centerlines and bronchoscope tip center information. The fiducial and target registration errors of our electromagnetic navigation system were about 6.6 and 4.5 mm in dynamic bronchial phantom validation.
NASA Astrophysics Data System (ADS)
Liu, Cheng; Cai, Guowei; Yang, Deyou; Sun, Zhenglong
2016-08-01
In this paper, a robust online approach based on wavelet transform and matrix pencil (WTMP) is proposed to extract the dominant oscillation mode and parameters (frequency, damping, and mode shape) of a power system from wide-area measurements. For accurate and robust extraction of parameters, WTMP is verified as an effective identification algorithm for output-only modal analysis. First, singular value decomposition (SVD) is used to reduce the covariance signals obtained by natural excitation technique. Second, the orders and range of the corresponding frequency are determined by SVD from positive power spectrum matrix. Finally, the modal parameters are extracted from each mode of reduced signals using the matrix pencil algorithm in different frequency ranges. Compared with the original algorithm, the advantage of the proposed method is that it reduces computation data size and can extract mode shape. The effectiveness of the scheme, which is used for accurate extraction of the dominant oscillation mode and its parameters, is thoroughly studied and verified using the response signal data generated from 4-generator 2-area and 16-generator 5-area test systems.
Energy-dependent correlations in the S-matrix of chaotic systems
NASA Astrophysics Data System (ADS)
Novaes, Marcel
2016-12-01
The M-dimensional unitary matrix S(E), which describes scattering of waves, is a strongly fluctuating function of the energy for complex systems such as ballistic cavities, whose geometry induces chaotic ray dynamics. Its statistical behaviour can be expressed by means of correlation functions of the kind <" separators=" S i j ( E + ɛ ) Sp q † ( E - ɛ ) > , which have been much studied within the random matrix approach. In this work, we consider correlations involving an arbitrary number of matrix elements and express them as infinite series in 1/M, whose coefficients are rational functions of ɛ. From a mathematical point of view, this may be seen as a generalization of the Weingarten functions of circular ensembles.
Investigation of fracture-matrix interaction: Preliminary experiments in a simple system
Foltz, S.D.; Tidwell, V.C.; Glass, R.J.; Sobolik, S.R.
1992-12-31
Paramount to the modeling of unsaturated flow and transport through fractured porous media is a clear understanding of the processes controlling fracture-matrix interaction. As a first step toward such an understanding, two preliminary experiments have been performed to investigate the influence of matrix imbibition on water percolation through unsaturated fractures in the plane normal to the fracture. Test systems consisted of thin slabs of either tuff or an analog material cut by a single vertical fracture into which a constant fluid flux was introduced. Transient moisture content and solute concentration fields were imaged by means of x-ray absorption. Flow fields associated with the two different media were significantly different owing to differences in material properties relative to the imposed flux. Richards` equation was found to be a valid means of modeling the imbibition of water into the tuff matrix from a saturated fracture for the current experiment.
Resistant starch as a carrier for oral colon-targeting drug matrix system.
Chen, Ling; Li, Xiaoxi; Pang, Yansheng; Li, Lin; Zhang, Ximei; Yu, Long
2007-11-01
In this study, a novel tablet of protein drug matrix for colon targeting was developed using resistant starch as a carrier prepared by pre-gelatinization and cross-linking of starch. The effects of pre-gelatinization and cross-linking on the swelling and enzymatic degradation of maize starch as well as the release rate of drug from the matrix tablets were examined. Cross-linked pre-gelatinized maize starches were prepared by double modification of pre-gelatinization and cross-linked with POCl(3), and bovine serum albumin was used as a model drug. For in vitro drug release assays, the resistant starch matrix tablets were incubated in simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid, respectively. The content of resistant starch and swelling property of maize starch were increased by pre-gelatinization and cross-linking, which retarded its enzymatic degradation. Drug release studies have shown that the matrix tablets of cross-linked pre-gelatinized maize starch could delivery the drug to the colon. These results indicate that the resistant starch carrier prepared by pre-gelatinization and cross-linking can be used for a potential drug delivery carrier for colon-targeting drug matrix delivery system.
NASA Astrophysics Data System (ADS)
Steele, Robert C. J.; Heber, Veronika S.; McKeegan, Kevin D.
2017-03-01
The short-lived radionuclide 53 Mn decays to 53 Cr providing a relative chronometer for dating the formation of Mn-rich minerals in meteorites. Secondary ion mass spectrometry (SIMS) has been extensively used for in situ dating of meteoritic olivine and carbonate by the 53 Mn-53 Cr system, however a significant analytical challenge has been realising accurate measurements of the Mn/Cr ratio in individual minerals of differing chemical compositions. During SIMS analysis, elements are ionised with differing efficiencies and standard materials are required to calibrate measured ion intensities in terms of relative elemental concentrations. The carbonate system presents a particular analytical difficulty since such standards are not naturally available due to low and variable Cr contents. Here, we utilise ion implantation of Cr into carbonate and other phases to accurately determine the relative sensitivity factors of Mn/Cr during SIMS analysis. We find significant variations in Mn/Cr RSF values among different carbonate minerals that depend systematically on chemical composition and we propose an empirical correction scheme that quantitatively yields an accurate RSF for carbonates of diverse chemical compositions. Correction of SIMS carbonate data for this strong matrix effect may help to reconcile some outstanding problems regarding the timescales of aqueous alteration processes in carbonaceous chondrites. Mn-Cr ages, revised based our new understanding of the matrix effect, are, in general, earlier than previously thought and the duration of carbonate formation is shorter.
Lee, Tai-Fen; Lee, Hao; Chen, Chung-Ming; Du, Shin-Hei; Cheng, Ya-Chih; Hsu, Chen-Ching; Chung, Meng-Yu; Teng, Shih-Hua; Teng, Lee-Jene; Hsueh, Po-Ren
2013-05-01
Among 30 urinary isolates of Staphylococcus saprophyticus identified by sequencing methods, the rate of accurate identification was 100% for Bruker Biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), 86.7% for the Phoenix PID and Vitek 2 GP systems, 93.3% for the MicroScan GP33 system, and 46.7% for the BBL CHROMagar Orientation system.
Yan, YiJing
2014-02-07
This work establishes a strongly correlated system-and-bath dynamics theory, the many-dissipaton density operators formalism. It puts forward a quasi-particle picture for environmental influences. This picture unifies the physical descriptions and algebraic treatments on three distinct classes of quantum environments, electron bath, phonon bath, and two-level spin or exciton bath, as their participating in quantum dissipation processes. Dynamical variables for theoretical description are no longer just the reduced density matrix for system, but remarkably also those for quasi-particles of bath. The present theoretical formalism offers efficient and accurate means for the study of steady-state (nonequilibrium and equilibrium) and real-time dynamical properties of both systems and hybridizing environments. It further provides universal evaluations, exact in principle, on various correlation functions, including even those of environmental degrees of freedom in coupling with systems. Induced environmental dynamics could be reflected directly in experimentally measurable quantities, such as Fano resonances and quantum transport current shot noise statistics.
Parameter identification of fractional order linear system based on Haar wavelet operational matrix.
Li, Yuanlu; Meng, Xiao; Zheng, Bochao; Ding, Yaqing
2015-11-01
Fractional order systems can be more adequate for the description of dynamical systems than integer order models, however, how to obtain fractional order models are still actively exploring. In this paper, an identification method for fractional order linear system was proposed. This is a method based on input-output data in time domain. The input and output signals are represented by Haar wavelet, and then fractional order systems described by fractional order differential equations are transformed into fractional order integral equations. Taking use of the Haar wavelet operational matrix of the fractional order integration, the fractional order linear system can easily be converted into a system of algebraic equation. Finally, the parameters of the fractional order system are determined by minimizing the errors between the output of the real system and that of the identified system. Numerical simulations, involving integral and fractional order systems, confirm the efficiency of the above methodology.
Iterative solutions to the steady-state density matrix for optomechanical systems
NASA Astrophysics Data System (ADS)
Nation, P. D.; Johansson, J. R.; Blencowe, M. P.; Rimberg, A. J.
2015-01-01
We present a sparse matrix permutation from graph theory that gives stable incomplete lower-upper preconditioners necessary for iterative solutions to the steady-state density matrix for quantum optomechanical systems. This reordering is efficient, adding little overhead to the computation, and results in a marked reduction in both memory and runtime requirements compared to other solution methods, with performance gains increasing with system size. Either of these benchmarks can be tuned via the preconditioner accuracy and solution tolerance. This reordering optimizes the condition number of the approximate inverse and is the only method found to be stable at large Hilbert space dimensions. This allows for steady-state solutions to otherwise intractable quantum optomechanical systems.
Koubar, Khodor; Bekaert, Virgile; Brasse, David; Laquerriere, Patrice
2015-06-01
Bone mineral density plays an important role in the determination of bone strength and fracture risks. Consequently, it is very important to obtain accurate bone mineral density measurements. The microcomputerized tomography system provides 3D information about the architectural properties of bone. Quantitative analysis accuracy is decreased by the presence of artefacts in the reconstructed images, mainly due to beam hardening artefacts (such as cupping artefacts). In this paper, we introduced a new beam hardening correction method based on a postreconstruction technique performed with the use of off-line water and bone linearization curves experimentally calculated aiming to take into account the nonhomogeneity in the scanned animal. In order to evaluate the mass correction rate, calibration line has been carried out to convert the reconstructed linear attenuation coefficient into bone masses. The presented correction method was then applied on a multimaterial cylindrical phantom and on mouse skeleton images. Mass correction rate up to 18% between uncorrected and corrected images were obtained as well as a remarkable improvement of a calculated mouse femur mass has been noticed. Results were also compared to those obtained when using the simple water linearization technique which does not take into account the nonhomogeneity in the object.
NASA Technical Reports Server (NTRS)
Goodwin, Sabine A.; Raj, P.
1999-01-01
Progress to date towards the development and validation of a fast, accurate and cost-effective aeroelastic method for advanced parallel computing platforms such as the IBM SP2 and the SGI Origin 2000 is presented in this paper. The ENSAERO code, developed at the NASA-Ames Research Center has been selected for this effort. The code allows for the computation of aeroelastic responses by simultaneously integrating the Euler or Navier-Stokes equations and the modal structural equations of motion. To assess the computational performance and accuracy of the ENSAERO code, this paper reports the results of the Navier-Stokes simulations of the transonic flow over a flexible aeroelastic wing body configuration. In addition, a forced harmonic oscillation analysis in the frequency domain and an analysis in the time domain are done on a wing undergoing a rigid pitch and plunge motion. Finally, to demonstrate the ENSAERO flutter-analysis capability, aeroelastic Euler and Navier-Stokes computations on an L-1011 wind tunnel model including pylon, nacelle and empennage are underway. All computational solutions are compared with experimental data to assess the level of accuracy of ENSAERO. As the computations described above are performed, a meticulous log of computational performance in terms of wall clock time, execution speed, memory and disk storage is kept. Code scalability is also demonstrated by studying the impact of varying the number of processors on computational performance on the IBM SP2 and the Origin 2000 systems.
Numerical Modeling on Two phase Fluid flow in a Coupled Fracture-Skin-Matrix System
NASA Astrophysics Data System (ADS)
Valsala Kumari, R.; G, S. K.
2015-12-01
Multiphase flow modeling studies below the ground surface is very essential for designing suitable remediation strategies for contaminated aquifers and for the development of petroleum and geothermal reservoirs. Presence of fractured bedrock beneath the ground surface will make multiphase flow process more complex due to its highly heterogeneous nature. A major challenge in modeling flow within a fractured rock is to capture the interaction between the high permeability fracture and the low permeability rock-matrix. In some instances, weathering and mineral depositions will lead to formation of an additional layer named fracture-skin at the fracture-matrix interface. Porosity and permeability of fracture-skin may significantly vary from the adjacent rock matrix and this variation will result in different flow and transport behavior within the fracture-skin. In the present study, an attempt has been made to model simultaneous flow of two immiscible phases (water and LNAPL) in a saturated coupled fracture-skin-matrix system. A fully-implicit finite difference model has been developed to simulate the variation of pressure and saturation of fluid phases along the fracture and within the rock-matrix. Sensitivity studies have been done to analyze the effect of change of various fracture-skin parameters such as porosity, diffusion coefficient and thickness on pressure and saturation distribution of both wetting and non-wetting fluid phases. It can be concluded from the study that the presence of fracture-skin is significantly affecting the fluid flow at the fracture-matrix interface and it can also be seen from the study that the flow behavior of both fluid phases is sensitive to fracture-skin parameters.
Price, Andrew P.; England, Kristen A.; Matson, Amy M.; Blazar, Bruce R.
2010-01-01
We developed a decellularized murine lung matrix bioreactor system that could be used to evaluate the potential of stem cells to regenerate lung tissue. Lungs from 2–3-month-old C57BL/6 female mice were excised en bloc with the trachea and heart, and decellularized with sequential solutions of distilled water, detergents, NaCl, and porcine pancreatic DNase. The remaining matrix was cannulated and suspended in small airway growth medium, attached to a ventilator to simulate normal, murine breathing-induced stretch. After 7 days in an incubator, lung matrices were analyzed histologically. Scanning electron microscopy and histochemical staining demonstrated that the pulmonary matrix was intact and that the geographic placement of the proximal and distal airways, alveoli and vessels, and the basement membrane of these structures all remained intact. Decellularization was confirmed by the absence of nuclear 4′,6-diamidino-2-phenylindole staining and negative polymerase chain reaction for genomic DNA. Collagen content was maintained at normal levels. Elastin, laminin, and glycosaminglycans were also present, although at lower levels compared to nondecellularized lungs. The decellularized lung matrix bioreactor was capable of supporting growth of fetal alveolar type II cells. Analysis of day 7 cryosections of fetal-cell-injected lung matrices showed pro-Sp-C, cytokeratin 18, and 4′,6-diamidino-2-phenylindole-positive cells lining alveolar areas that appeared to be attached to the matrix. These data illustrate the potential of using decellularized lungs as a natural three-dimensional bioengineering matrix as well as provide a model for the study of lung regeneration from pulmonary stem cells. PMID:20297903
Method to modify random matrix theory using short-time behavior in chaotic systems.
Smith, A Matthew; Kaplan, Lev
2009-09-01
We discuss a modification to random matrix theory (RMT) eigenstate statistics that systematically takes into account the nonuniversal short-time behavior of chaotic systems. The method avoids diagonalization of the Hamiltonian, instead requiring only knowledge of short-time dynamics for a chaotic system or ensemble of similar systems. Standard RMT and semiclassical predictions are recovered in the limits of zero Ehrenfest time and infinite Heisenberg time, respectively. As examples, we discuss wave-function autocorrelations and cross correlations and show how the approach leads to a significant improvement in the accuracy for simple chaotic systems where comparison can be made with brute-force diagonalization.
Van Yperen-De Deyne, A; Pauwels, E; Van Speybroeck, V; Waroquier, M
2012-08-14
In this paper an overview is presented of several approximations within Density Functional Theory (DFT) to calculate g-tensors in transition metal containing systems and a new accurate description of the spin-other-orbit contribution for high spin systems is suggested. Various implementations in a broad variety of software packages (ORCA, ADF, Gaussian, CP2K, GIPAW and BAND) are critically assessed on various aspects including (i) non-relativistic versus relativistic Hamiltonians, (ii) spin-orbit coupling contributions and (iii) the gauge. Particular attention is given to the level of accuracy that can be achieved for codes that allow g-tensor calculations under periodic boundary conditions, as these are ideally suited to efficiently describe extended condensed-phase systems containing transition metals. In periodic codes like CP2K and GIPAW, the g-tensor calculation schemes currently suffer from an incorrect treatment of the exchange spin-orbit interaction and a deficient description of the spin-other-orbit term. In this paper a protocol is proposed, making the predictions of the exchange part to the g-tensor shift more plausible. Focus is also put on the influence of the spin-other-orbit interaction which becomes of higher importance for high-spin systems. In a revisited derivation of the various terms arising from the two-electron spin-orbit and spin-other-orbit interaction (SOO), new insight has been obtained revealing amongst other issues new terms for the SOO contribution. The periodic CP2K code has been adapted in view of this new development. One of the objectives of this study is indeed a serious enhancement of the performance of periodic codes in predicting g-tensors in transition metal containing systems at the same level of accuracy as the most advanced but time consuming spin-orbit mean-field approach. The methods are first applied on rhodium carbide but afterwards extended to a broad test set of molecules containing transition metals from the fourth
NASA Astrophysics Data System (ADS)
Tadokoro, K.; Yasuda, K.; Taniguchi, S.; Uemura, Y.; Matsuhiro, K.
2015-12-01
The GPS/acoustic sea-floor crustal deformation measurement system has developed as a useful tool to observe tectonic deformation especially at subduction zones. One of the factors preventing accurate GPS/acoustic sea-floor crustal deformation measurement is horizontal heterogeneity of sound speed in the ocean. It is therefore necessary to measure the gradient directly from sound speed structure. We report results of high-frequency CTD measurements using Underway CTD (UCTD) in the Kuroshio region. We perform the UCTD measurements on May 2nd, 2015 at two stations (TCA and TOA) above the sea-floor benchmarks installed across the Nankai Trough, off the south-east of Kii Peninsula, middle Japan. The number of measurement points is six at each station along circles with a diameter of 1.8 nautical miles around the sea-floor benchmark. The stations TCA and TOA are located on the edge and the interior of the Kuroshio current, respectively, judging from difference in sea water density measured at the two stations, as well as a satellite image of sea-surface temperature distribution. We detect a sound speed gradient of high speeds in the southern part and low speeds in the northern part at the two stations. At the TCA station, the gradient is noticeable down to 300 m in depth; the maximum difference in sound speed is +/- 5 m/s. The sound speed difference is as small as +/- 1.3 m/s at depths below 300 m, which causes seafloor benchmark positioning error as large as 1 m. At the TOA station, the gradient is extremely small down to 100 m in depth. The maximum difference in sound speed is less than +/- 0.3 m/s that is negligible small for seafloor benchmark positioning error. Clear gradient of high speed is observed to the depths; the maximum difference in sound speed is +/- 0.8-0.9 m/s, causing seafloor benchmark positioning error of several tens centimeters. The UCTD measurement is effective tool to detect sound speed gradient. We establish a method for accurate sea
Developing a Health Information Technology Systems Matrix: A Qualitative Participatory Approach
Chavez, Margeaux; Nazi, Kim M; Antinori, Nicole
2016-01-01
Background The US Department of Veterans Affairs (VA) has developed various health information technology (HIT) resources to provide accessible veteran-centered health care. Currently, the VA is undergoing a major reorganization of VA HIT to develop a fully integrated system to meet consumer needs. Although extensive system documentation exists for various VA HIT systems, a more centralized and integrated perspective with clear documentation is needed in order to support effective analysis, strategy, planning, and use. Such a tool would enable a novel view of what is currently available and support identifying and effectively capturing the consumer’s vision for the future. Objective The objective of this study was to develop the VA HIT Systems Matrix, a novel tool designed to describe the existing VA HIT system and identify consumers’ vision for the future of an integrated VA HIT system. Methods This study utilized an expert panel and veteran informant focus groups with self-administered surveys. The study employed participatory research methods to define the current system and understand how stakeholders and veterans envision the future of VA HIT and interface design (eg, look, feel, and function). Directed content analysis was used to analyze focus group data. Results The HIT Systems Matrix was developed with input from 47 veterans, an informal caregiver, and an expert panel to provide a descriptive inventory of existing and emerging VA HIT in four worksheets: (1) access and function, (2) benefits and barriers, (3) system preferences, and (4) tasks. Within each worksheet is a two-axis inventory. The VA’s existing and emerging HIT platforms (eg, My HealtheVet, Mobile Health, VetLink Kiosks, Telehealth), My HealtheVet features (eg, Blue Button, secure messaging, appointment reminders, prescription refill, vet library, spotlight, vitals tracker), and non-VA platforms (eg, phone/mobile phone, texting, non-VA mobile apps, non-VA mobile electronic devices, non
2004-06-01
UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP023843 TITLE: Time Accurate Unsteady Simulation of the Stall Inception...report: ADP023820 thru ADP023869 UNCLASSIFIED Time Accurate Unsteady Simulation of the Stall Inception Process in the Compression System of a US Army...surface ships, tanks, manned and Improved understanding of the stall inception process and unmanned fixed-wing and rotary-wing combat aircraft, how stall
1990-09-01
autonomous discovery learning, where the learner identifies and selects the information to be learned(l:7). Figure I shows how the two continua form a...using computer generatcd graphics; and a fortuitous consequence of selecting matrix operations was that the operations form a family of concepts that...blinking prompts, and some animation. Although an extensive organon exists about the visual aspects of information display, this study relied solely on
Implementation of parallel matrix decomposition for NIKE3D on the KSR1 system
Su, Philip S.; Fulton, R.E.; Zacharia, T.
1995-06-01
New massively parallel computer architecture has revolutionized the design of computer algorithms and promises to have significant influence on algorithms for engineering computations. Realistic engineering problems using finite element analysis typically imply excessively large computational requirements. Parallel supercomputers that have the potential for significantly increasing calculation speeds can meet these computational requirements. This report explores the potential for the parallel Cholesky (U{sup T}DU) matrix decomposition algorithm on NIKE3D through actual computations. The examples of two- and three-dimensional nonlinear dynamic finite element problems are presented on the Kendall Square Research (KSR1) multiprocessor system, with 64 processors, at Oak Ridge National Laboratory. The numerical results indicate that the parallel Cholesky (U{sup T}DU) matrix decomposition algorithm is attractive for NIKE3D under multi-processor system environments.
Matrix metalloproteinases: a review of their structure and role in systemic sclerosis.
Peng, Wen-jia; Yan, Jun-wei; Wan, Ya-nan; Wang, Bing-xiang; Tao, Jin-hui; Yang, Guo-jun; Pan, Hai-feng; Wang, Jing
2012-12-01
Matrix metalloproteinases (MMPs) are the main enzymes involved in arterial wall extracellular matrix (ECM) degradation and remodeling, whose activity has been involved in various normal and pathologic processes, such as inflammation, fibrosis. As a result, the MMPs have come to consider as both therapeutic targets and diagnostic tools for the treatment and diagnosis of autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis. Systemic sclerosis (SSc) is a rare autoimmune disease of unknown etiology characterized by an excessive over-production of collagen and other ECM, resulting in skin thickening and fibrosis of internal organs. In recent years, abnormal expression of MMPs has been demonstrated with the pathogenesis of SSc, and the association of different polymorphisms on MMPs genes with SSc has been extensively studied. This review describes the structure, function and regulation of MMPs and shortly summarizes current understanding on experimental findings, genetic associations of MMPs in SSc.
Thin Film Heat Flux Sensor Development for Ceramic Matrix Composite (CMC) Systems
NASA Technical Reports Server (NTRS)
Wrbanek, John D.; Fralick, Gustave C.; Hunter, Gary W.; Zhu, Dongming; Laster, Kimala L.; Gonzalez, Jose M.; Gregory, Otto J.
2010-01-01
The NASA Glenn Research Center (GRC) has an on-going effort for developing high temperature thin film sensors for advanced turbine engine components. Stable, high temperature thin film ceramic thermocouples have been demonstrated in the lab, and novel methods of fabricating sensors have been developed. To fabricate thin film heat flux sensors for Ceramic Matrix Composite (CMC) systems, the rough and porous nature of the CMC system posed a significant challenge for patterning the fine features required. The status of the effort to develop thin film heat flux sensors specifically for use on silicon carbide (SiC) CMC systems with these new technologies is described.
Development of a sensor and control system for the production of titanium matrix composites
Berzins, L.V.; McClelland, M.A.; Anklam, T.M.
1995-03-01
Titanium matrix composites promise to dramatically increase the thrust-to-weight ratio of gas turbine engines. Electron Beam Physical Vapor Deposition (EB-PVD) is ideal for coating fibers if issues with composition control can be worked out. LLNL is developing a control system based on Diode Laser Absorption Spectroscopy (DLAS) for the deposition of titanium orthorhombic alloys. In this paper, the important features and components of a DLAS control system are reviewed and a methodology for selecting the appropriate atomic transitions is described. Data characterizing the diagnostic performance as well as information on potential control strategies is presented. Finally, applications of this diagnostic to other alloy systems are discussed.
1981-01-13
rings usual theory in which coefficients of x(t) and u(t) are approach is based on generalizations of state space tech- constant, but generalized to...AFOSR-WO) 196. P. P. Khargonekar is with the Center for Mathematical System Theory control-theoretic problems (output regulation. tracking, and and the...denote the minimal possible cardinafity of a set our approach here and that in recent transfer matrix design of generators for the module X. /All "modules
Lao, Ka Un; Herbert, John M
2015-01-15
We present an overview of "XSAPT", a family of quantum chemistry methods for noncovalent interactions. These methods combine an efficient, iterative, monomer-based approach to computing many-body polarization interactions with a two-body version of symmetry-adapted perturbation theory (SAPT). The result is an efficient method for computing accurate intermolecular interaction energies in large noncovalent assemblies such as molecular and ionic clusters, molecular crystals, clathrates, or protein-ligand complexes. As in traditional SAPT, the XSAPT energy is decomposable into physically meaningful components. Dispersion interactions are problematic in traditional low-order SAPT, and two new approaches are introduced here in an attempt to improve this situation: (1) third-generation empirical atom-atom dispersion potentials, and (2) an empirically scaled version of second-order SAPT dispersion. Comparison to high-level ab initio benchmarks for dimers, water clusters, halide-water clusters, a methane clathrate hydrate, and a DNA intercalation complex illustrate both the accuracy of XSAPT-based methods as well as their limitations. The computational cost of XSAPT scales as O(N(3))-O(N(5)) with respect to monomer size, N, depending upon the particular version that is employed, but the accuracy is typically superior to alternative ab initio methods with similar scaling. Moreover, the monomer-based nature of XSAPT calculations makes them trivially parallelizable, such that wall times scale linearly with respect to the number of monomer units. XSAPT-based methods thus open the door to both qualitative and quantitative studies of noncovalent interactions in clusters, biomolecules, and condensed-phase systems.
Bahrehmand, F; Vaisi-Raygani, A; Kiani, A; Rahimi, Z; Tavilani, H; Ardalan, M; Vaisi-Raygani, H; Shakiba, E; Pourmotabbed, T
2015-05-01
Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple organs and is characterized by persistent systemic inflammation. Among the effects of inflammatory mediators, the induction of matrix metalloproteinases-2 and -9 (MMP-2 and MMP-9) and oxidative stress has been demonstrated to be important in the development of SLE. In this study, the possible association between MMP-9 and MMP-2 functional promoter polymorphism, stress, and inflammatory markers with development of severe cardiovascular disease (CVD), high blood pressure (HBP), and lupus nephropathy (LN) in SLE patients was investigated. The present case-control study consisted of 109 SLE patients with and without CVD, HBP and LN and 101 gender- and age-matched unrelated healthy controls from a population in western Iran. MMP-2 -G1575A and MMP-9 -C1562T polymorphisms were detected by PCR-RFLP, serum MMP-2 and MMP-9, neopterin, malondialdehyde (MDA) and lipid levels were determined by ELISA, HPLC and enzyme assay, respectively. We found that MMP-9 -C1562 T and MMP-2 -G1575A alleles act synergistically to increase the risk of SLE by 2.98 times (p = 0.015). Findings of this study also demonstrated that there is a significant increase in the serum levels of MMP-2, neopterin and MDA and a significant decrease in serum level of MMP-9 in the presence of MMP-9-C1562 T and MMP-2 -G1575A alleles in SLE patients compared to controls. Further, SLE patients with MMP-9 (C/T + T/T) genotype had significantly higher serum concentrations of MMP-2, neopterin, MDA and LDL-C, but lower serum MMP-9 and HDL-C levels than corresponding members of the control group. MMP-9 (C/T + T/T) genotype increased risk of hypertension in SLE patients 2.71-fold. This study for the first time not only suggests that MMP-9 -C1562 T and MMP-2 -G1575A alleles synergistically increase the risk of SLE but also high serum levels of MDA, neopterin, and circulatory levels of MMP-2 and lower MMP-9 in SLE patients. This
Systems and methods for commutating inductor current using a matrix converter
Ransom, Ray M; Kajouke, Lateef A; Perisic, Milun
2012-10-16
Systems and methods are provided for delivering current using a matrix converter in a vehicle. An electrical system comprises an AC interface, a first conversion module coupled to the AC interface, an inductive element coupled between the AC interface and the first conversion module, and a control module coupled to the first conversion module. The control module is configured to operate the first conversion module in a bidirectional operating mode to commutate current bidirectionally. When a magnitude of the current through the inductive element is greater than a first threshold value, the control module operates the conversion module in a unidirectional operating mode, wherein current is commutated unidirectionally.
NASA Astrophysics Data System (ADS)
Hoek, W. Z.; Kasse, C.; Peeters, J.; Wallinga, J.
2009-04-01
The River Rhine occupied the Niers Valley (Germany) from the Saalian Glaciation (MIS 6) until the Early Holocene (Kasse et al., Journal of Quaternary Science 2005). The fluvial landscape of the time of abandonment has been exceptionally well preserved, leaving a series of cut-off meanders and residual channels. This unique preservation provides the possibility to investigate Late Weichselian fluvial dynamics of the River Rhine. We combined several dating techniques to accurately determine the age of the deposits. We developed a sampling strategy based on detailed field survey and cross sectioning. 1) The geomorphological relationships of the cut-off meanders gave a relative age for the successive stages of meandering. 2) The occurrence of Laacher See Pumice in the point bar deposits gave a maximum age for these deposits. 3) Optically Stimulated Luminescence (OSL)-dating on sandy point bar and channel-fill deposits yielded absolute ages for active meandering and channel abandonment. 4) AMS-14C dates on terrestrial macrofossils from the basal fills of the residual channels yielded minimum ages for abandonment. 5) Biostratigraphy of the organic channel fills using palynology gave a relative chronology, which could be linked to the well-dated regional biostratigraphy of the nearby Netherlands and is cross-checked by additional AMS-14C dates. By combining these dating techniques we obtained a firm chronological framework that allows linkage to climate records and above the cross-validation of the different dating techniques. All techniques gave consistent ages that confirm the Lateglacial age and Early Holocene abandonment of the Niers Valley by the River Rhine. Palynology and 14C-dating on the channels fills supported the relative chronology indicated by the cross-cut relationships. The presence of the Laacher See Pumice in the point bar deposits, which has an unambiguous age of 12.9 ka cal. BP concurs with the organic channel fill ages. Because OSL signals in some
Technology Transfer Automated Retrieval System (TEKTRAN)
Application of crop production and protection materials is a crucial component in the high productivity of American agriculture. Agricultural chemical application is frequently needed at a specific time and location for accurate site-specific management of crop pests. Piloted aircrafts that carry ...
Production of metal matrix composite mirrors for tank fire control systems
NASA Astrophysics Data System (ADS)
Geiger, Alan L.; Ulph, Eric, Sr.
1992-09-01
The first production lot of 50 units of metal matrix composite mirrors for the Leopard I tank fire control system was recently completed by Optical Corporation of America (OCA), Garden Grove, California. The mirror substrates were finish machined from forgings of Optical Grade SXATM metal matrix composite manufactured by Advanced Composite Materials Corporation (ACMC), Greer, South Carolina. Use of forgings rather than hot pressed billet yields more efficient use of material and reduces machining time, resulting in lower cost. The mirrors were fabricated by a process sequence of machining, thermal stabilization, electroless nickel plating, polishing, and coating with a high efficiency, laser damage-resistant optical coating. The mirrors are used in the fire control system for a day channel (direct view) and near infrared (CCD), a muzzle reference system laser transceiver, a laser range finder, and an infrared thermal imaging system. SXA composite was chosen over competitive mirror materials (glass and beryllium) because of its high specific strength and stiffness, good stability, and moderate machining cost. The mirrors exhibit excellent stability and optical performance. Field trials of prototype mirrors in fire control systems have proven successful.
NASA Astrophysics Data System (ADS)
Tomczewski, Slawomir; Salbut, Leszek
We present detection of inhomogeneities in amorphous corundum layers by optical coherence tomography system with CMOS matrix detector. The presented setup is based on modified Twyman-Green interferometer with specially designed scanning module. The module consists of two beam directing mirrors, a beam splitter, an objective lens and it's illuminated by a high-power pig-tailed light emitting diode. The system is calibrated that the objective gives image of zero optical path difference plane in infinity. Due to this and because the matrix detector is placed in the focal plane of an imaging lens, therefore even if distance between the objective and the imaging lens changes during scanning process, the zero optical path difference plane is always in-focus. Hence the system focuses itself on imaged layers and there is no drop in transverse resolution coming from defocusing. In the paper we present, the idea of self-focusing tomographic system, its theoretical analysis and design aspects. Calibration of proposed system and its application for measurement of amorphous corundum layers are also presented. The measurements results show occurrences of the inhomogeneities in the investigated samples.
Tissue matrix arrays for high throughput screening and systems analysis of cell function
Beachley, Vince Z.; Wolf, Matthew T.; Sadtler, Kaitlyn; Manda, Srikanth S.; Jacobs, Heather; Blatchley, Michael; Bader, Joel S.; Pandey, Akhilesh; Pardoll, Drew; Elisseeff, Jennifer H.
2015-01-01
Cell and protein arrays have demonstrated remarkable utility in the high-throughput evaluation of biological responses; however, they lack the complexity of native tissue and organs. Here, we describe tissue extracellular matrix (ECM) arrays for screening biological outputs and systems analysis. We spotted processed tissue ECM particles as two-dimensional arrays or incorporated them with cells to generate three-dimensional cell-matrix microtissue arrays. We then investigated the response of human stem, cancer, and immune cells to tissue ECM arrays originating from 11 different tissues, and validated the 2D and 3D arrays as representative of the in vivo microenvironment through quantitative analysis of tissue-specific cellular responses, including matrix production, adhesion and proliferation, and morphological changes following culture. The biological outputs correlated with tissue proteomics, and network analysis identified several proteins linked to cell function. Our methodology enables broad screening of ECMs to connect tissue-specific composition with biological activity, providing a new resource for biomaterials research and translation. PMID:26480475
Lacroix, C; Gicquel, A; Sendid, B; Meyer, J; Accoceberry, I; François, N; Morio, F; Desoubeaux, G; Chandenier, J; Kauffmann-Lacroix, C; Hennequin, C; Guitard, J; Nassif, X; Bougnoux, M-E
2014-02-01
Candida spp. are responsible for severe infections in immunocompromised patients and those undergoing invasive procedures. The accurate identification of Candida species is important because emerging species can be associated with various antifungal susceptibility spectra. Conventional methods have been developed to identify the most common pathogens, but have often failed to identify uncommon species. Several studies have reported the efficiency of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of clinically relevant Candida species. In this study, we evaluated two commercially available MALDI-TOF systems, Andromas™ and Bruker Biotyper™, for Candida identification in routine diagnosis. For this purpose, we investigated 1383 Candida isolates prospectively collected in eight hospital laboratories during routine practice. MALDI-TOF MS results were compared with those obtained using conventional phenotypic methods. Analysis of rDNA gene sequences with internal transcribed regions or D1-D2 regions is considered the reference standard for identification. Both MALDI-TOF MS systems could accurately identify 98.3% of the isolates at the species level (1359/1383 for Andromas™; 1360/1383 for Bruker Biotyper™) vs. 96.5% for conventional techniques. Furthermore, whereas conventional methods failed to identify rare or emerging species, these were correctly identified by MALDI-TOF MS. Both MALDI-TOF MS systems are accurate and cost-effective alternatives to conventional methods for mycological identification of clinically relevant Candida species and should improve the diagnosis of fungal infections as well as patient management.
Ullah, Farman; Sarwar, Ghulam; Lee, Sungchang
2014-01-01
We propose a network and visual quality aware N-Screen content recommender system. N-Screen provides more ways than ever before to access multimedia content through multiple devices and heterogeneous access networks. The heterogeneity of devices and access networks present new questions of QoS (quality of service) in the realm of user experience with content. We propose, a recommender system that ensures a better visual quality on user's N-screen devices and the efficient utilization of available access network bandwidth with user preferences. The proposed system estimates the available bandwidth and visual quality on users N-Screen devices and integrates it with users preferences and contents genre information to personalize his N-Screen content. The objective is to recommend content that the user's N-Screen device and access network are capable of displaying and streaming with the user preferences that have not been supported in existing systems. Furthermore, we suggest a joint matrix factorization approach to jointly factorize the users rating matrix with the users N-Screen device similarity and program genres similarity. Finally, the experimental results show that we also enhance the prediction and recommendation accuracy, sparsity, and cold start issues. PMID:24982999
Repka, Michael A.; Munjal, Manish; ElSohly, Mahmoud A.; Ross, Samir A.
2010-01-01
The purpose of this study was to determine and compare the bioadhesive profiles of hydroxypropylcellulose (HPC) polymer matrices as a function of Δ9-tetrahydrocannabinol (THC) content. In addition, the effect of processing temperature on the stability of THC and its extent of degradation to cannabinol (CBN) was investigated. A hot-melt cast molding method was used to prepare HPC polymer matrix systems incorporated with THC at 0, 4, 8, and 16 percent. Bioadhesive measurements including peak adhesive force, area under the curve, and elongation at adhesive failure were recorded utilizing the TA.XT2i Texture Analyzer™. Data obtained from these tests at various contact time intervals suggested that the incorporation of THC led to an increase in the bioadhesive strength of the HPC polymer matrices. To determine the stability of THC and the resulting CBN content in the matrices, three different processing temperatures were utilized (120, 160, and 200°C). Post-production High Performance Liquid Chromotography (HPLC) analysis revealed that the processed systems contained at least 94% of THC and the relative percent formation of CBN was 0.5% at 120°C and 0.4% at 160°C compared to 1.6% at 200°C. These findings indicate that the cannabinoid may be a plausible candidate for incorporation into systems utilizing hot-melt extrusion techniques for the development of an effective mucoadhesive transmucosal matrix system for delivery of THC. PMID:16455601
Current-induced forces in mesoscopic systems: A scattering-matrix approach.
Bode, Niels; Kusminskiy, Silvia Viola; Egger, Reinhold; von Oppen, Felix
2012-01-01
Nanoelectromechanical systems are characterized by an intimate connection between electronic and mechanical degrees of freedom. Due to the nanoscopic scale, current flowing through the system noticeably impacts upons the vibrational dynamics of the device, complementing the effect of the vibrational modes on the electronic dynamics. We employ the scattering-matrix approach to quantum transport in order to develop a unified theory of nanoelectromechanical systems out of equilibrium. For a slow mechanical mode the current can be obtained from the Landauer-Büttiker formula in the strictly adiabatic limit. The leading correction to the adiabatic limit reduces to Brouwer's formula for the current of a quantum pump in the absence of a bias voltage. The principal results of the present paper are the scattering-matrix expressions for the current-induced forces acting on the mechanical degrees of freedom. These forces control the Langevin dynamics of the mechanical modes. Specifically, we derive expressions for the (typically nonconservative) mean force, for the (possibly negative) damping force, an effective "Lorentz" force that exists even for time-reversal-invariant systems, and the fluctuating Langevin force originating from Nyquist and shot noise of the current flow. We apply our general formalism to several simple models that illustrate the peculiar nature of the current-induced forces. Specifically, we find that in out-of-equilibrium situations the current-induced forces can destabilize the mechanical vibrations and cause limit-cycle dynamics.
NASA Astrophysics Data System (ADS)
Wang, Xiaoting; Allegra, Michele; Jacobs, Kurt; Lloyd, Seth; Lupo, Cosmo; Mohseni, Masoud
2015-05-01
Most methods of optimal control cannot obtain accurate time-optimal protocols. The quantum brachistochrone equation is an exception, and has the potential to provide accurate time-optimal protocols for a wide range of quantum control problems. So far, this potential has not been realized, however, due to the inadequacy of conventional numerical methods to solve it. Here we show that the quantum brachistochrone problem can be recast as that of finding geodesic paths in the space of unitary operators. We expect this brachistochrone-geodesic connection to have broad applications, as it opens up minimal-time control to the tools of geometry. As one such application, we use it to obtain a fast numerical method to solve the brachistochrone problem, and apply this method to two examples demonstrating its power.
The discrete hungry Lotka Volterra system and a new algorithm for computing matrix eigenvalues
NASA Astrophysics Data System (ADS)
Fukuda, Akiko; Ishiwata, Emiko; Iwasaki, Masashi; Nakamura, Yoshimasa
2009-01-01
The discrete hungry Lotka-Volterra (dhLV) system is a generalization of the discrete Lotka-Volterra (dLV) system which stands for a prey-predator model in mathematical biology. In this paper, we show that (1) some invariants exist which are expressed by dhLV variables and are independent from the discrete time and (2) a dhLV variable converges to some positive constant or zero as the discrete time becomes sufficiently large. Some characteristic polynomial is then factorized with the help of the dhLV system. The asymptotic behaviour of the dhLV system enables us to design an algorithm for computing complex eigenvalues of a certain band matrix.
Lund, A; Andersson, P; Eriksson, J; Hallin, J; Johansson, T; Jonsson, R; Löfgren, H; Paulin, C; Tell, A
2008-05-01
Two types of automatic fitting procedures for EPR spectra of disordered systems have been developed, one based on matrix diagonalization of a general spin Hamiltonian, the other on 2nd order perturbation theory. The first program is based on a previous Fortran code complemented with a newly written interface in Java to provide user-friendly in and output. The second is intended for the special case of free radicals with several relatively weakly interacting nuclei, in which case the general method becomes slow. A least squares' fitting procedure utilizing analytical or numerical derivatives of the theoretically calculated spectrum with respect to the g- and hyperfine structure (hfs) tensors was used to refine those parameters in both cases. 'Rigid limit' ESR spectra from radicals in organic matrices and in polymers, previously studied experimentally at low temperature, were analyzed by both methods. Fluorocarbon anion radicals could be simulated, quite accurately with the exact method, whereas automatic fitting on, e.g. the c-C(4)F(8)(-) anion radical is only feasible with the 2nd order approximative treatment. Initial values for the (19)F hfs tensors estimated by DFT calculations were quite close to the final. For neutral radicals of the type XCF(2)CF(2)* the refinement of the hfs tensors by the exact method worked better than the approximate. The reasons are discussed. The ability of the fitting procedures to recover the correct magnetic parameters of disordered systems was investigated by fittings to synthetic spectra with known hfs tensors. The exact and the approximate methods are concluded to be complementary, one being general, but limited to relatively small systems, the other being a special treatment, suited for S=1/2 systems with several moderately large hfs.
The Split Coefficient Matrix method for hyperbolic systems of gasdynamic equations
NASA Technical Reports Server (NTRS)
Chakravarthy, S. R.; Anderson, D. A.; Salas, M. D.
1980-01-01
The Split Coefficient Matrix (SCM) finite difference method for solving hyperbolic systems of equations is presented. This new method is based on the mathematical theory of characteristics. The development of the method from characteristic theory is presented. Boundary point calculation procedures consistent with the SCM method used at interior points are explained. The split coefficient matrices that define the method for steady supersonic and unsteady inviscid flows are given for several examples. The SCM method is used to compute several flow fields to demonstrate its accuracy and versatility. The similarities and differences between the SCM method and the lambda-scheme are discussed.
Superstatistical random-matrix-theory approach to transition intensities in mixed systems.
Abul-Magd, A Y
2006-05-01
We study the fluctuation properties of transition intensities applying a recently proposed generalization of the random matrix theory, which is based on Beck and Cohen's superstatistics. We obtain an analytic expression for the distribution of the reduced transition probabilities that applies to systems undergoing a transition out of chaos. The obtained distribution fits the results of a previous nuclear shell model calculations for some electromagnetic transitions that deviate from the Porter-Thomas distribution. It agrees with the experimental reduced transition probabilities for the nucleus better than the commonly used chi(2) distribution.
Extracellular matrix-inspired growth factor delivery systems for bone regeneration
Martino, Mikaël M.; Briquez, Priscilla S.; Maruyama, Kenta; Hubbell, Jeffrey A.
2015-04-17
Growth factors are very promising molecules to enhance bone regeneration. However, their translation to clinical use has been seriously limited, facing issues related to safety and cost-effectiveness. These problems derive from the vastly supra-physiological doses of growth factor used without optimized delivery systems. Therefore, these issues have motivated the development of new delivery systems allowing better control of the spatio-temporal release and signaling of growth factors. Because the extracellular matrix (ECM) naturally plays a fundamental role in coordinating growth factor activity in vivo, a number of novel delivery systems have been inspired by the growth factor regulatory function of the ECM. After introducing the role of growth factors during the bone regeneration process, this review exposes different issues that growth factor-based therapies have encountered in the clinic and highlights recent delivery approaches based on the natural interaction between growth factor and the ECM.
Performance analysis of cross-seeding WDM-PON system using transfer matrix method
NASA Astrophysics Data System (ADS)
Simatupang, Joni Welman; Pukhrambam, Puspa Devi; Huang, Yen-Ru
2016-12-01
In this paper, a model based on the transfer matrix method is adopted to analyze the effects of Rayleigh backscattering and Fresnel multiple reflections on a cross-seeding WDM-PON system. As part of analytical approximation methods, this time-independent model is quite simple but very efficient when it is applied to various WDM-PON transmission systems, including the cross-seeding scheme. The cross seeding scheme is most beneficial for systems with low loop-back ONU gain or low reflection loss at the drop fiber for upstream data in bidirectional transmission. However for downstream data transmission, multiple reflections power could destroy the usefulness of the cross-seeding scheme when the reflectivity is high enough and the RN is positioned near OLT or close to ONU.
Computationally efficient gradient matrix of optical path length in axisymmetric optical systems.
Hsueh, Chun-Che; Lin, Psang-Dain
2009-02-10
We develop a mathematical method for determining the optical path length (OPL) gradient matrix relative to all the system variables such that the effects of variable changes can be evaluated in a single pass. The approach developed avoids the requirement for multiple ray-tracing operations and is, therefore, more computationally efficient. By contrast, the effects of variable changes on the OPL of an optical system are generally evaluated by utilizing a ray-tracing approach to determine the OPL before and after the variable change and then applying a finite-difference (FD) approximation method to estimate the OPL gradient with respect to each individual variable. Utilizing a Petzval lens system for verification purposes, it is shown that the approach developed reduces the computational time by around 90% compared to that of the FD method.
Construction of Lyapunov Function for Power System based on Solving Linear Matrix Inequality
NASA Astrophysics Data System (ADS)
Ishigame, Atsushi; Sakaguchi, Hiromu; Takashima, Jun; Suzaki, Shirou
This paper presents a constructing Lyapunov function for power system based on solving the Linear Matrix Inequality (LMI) derived from the Lyapunov stability theorem considering with dynamics of load characteristic and AVR control system. The proposed Lyapunov function is constructed as a quadratic form of state variables and an integral term which satisfies the curl equation and the sector condition. An induction machine and a synchronous machine are considered as load characteristics. One machine and one load infinite bus system is considered taking into account the flux decay effects and AVR with one time constant of the generator. To verify the proposed Lyapunov function, the transient stability assessment is shown. The critical clearing times given by the proposed Lyapunov function are compared with those obtained by the numerical integration method, and they are shown to be practical.
NASA Astrophysics Data System (ADS)
Caballero, B.; García-Martín, A.; Cuevas, J. C.
2012-06-01
We present here a generalization of the scattering-matrix approach for the description of the propagation of electromagnetic waves in nanostructured magneto-optical systems. Our formalism allows us to describe all the key magneto-optical effects in any configuration in periodically patterned multilayer structures. The method can also be applied to describe periodic multilayer systems comprising materials with any type of optical anisotropy. We illustrate the method with the analysis of a recent experiment in which the transverse magneto-optical Kerr effect was measured in an Fe film with a periodic array of subwavelength circular holes. We show, in agreement with the experiments, that the excitation of surface plasmon polaritons in this system leads to a resonant enhancement of the transverse magneto-optical Kerr effect.
Development of new and improved polymer matrix resin systems, phase 1
NASA Technical Reports Server (NTRS)
Hsu, M. S.
1983-01-01
Vinystilbazole (vinylstryrylpyridine) and vinylpolystyrulpyridine were prepared for the purpose of modifying bismaleimide composite resins. Cure studies of resins systems were investigated by differential scanning calorimetry. The vinylstyrylpyridine-modified bismaleimide composite resins were found to have lower cure and gel temperatures, and shorter cure times than the corresponding unmodified composite resins. The resin systems were reinforced with commercially avialable satin-weave carbon cloth. Prepregs were fabricated by solvent or hot melt techniques. Thermal stability, flammability, moisture absorption, and mechanical properties of the composites (such as flexural strength, modulus, tensile and short beam shear strength) were determined. Composite laminates showed substantial improvements in both processability and mechanical properties compared to he bismaleimide control systems. The vinylstyrylpyridine modified bismaleimide resins can be used as advanced matrix resins for graphite secondary structures where ease of processing, fireworthiness, and high temperature stability are required for aerospace applications.
Density matrix renormalization group approach to two-fluid open many-fermion systems
NASA Astrophysics Data System (ADS)
Rotureau, J.; Michel, N.; Nazarewicz, W.; Płoszajczak, M.; Dukelsky, J.
2009-01-01
We have extended the density matrix renormalization group (DMRG) approach to two-fluid open many-fermion systems governed by complex-symmetric Hamiltonians. The applications are carried out for three- and four-nucleon (proton-neutron) systems within the Gamow shell model (GSM) in the complex-energy plane. We study necessary and sufficient conditions for the GSM+DMRG method to yield the correct ground-state eigenvalue and discuss different truncation schemes within the DMRG. The proposed approach will enable configuration interaction studies of weakly bound and unbound strongly interacting complex systems, which, because of a prohibitively large size of Fock space, cannot be treated by means of the direct diagonalization.
Scaling laws for the largest Lyapunov exponent in long-range systems: A random matrix approach.
Anteneodo, Celia; Vallejos, Raúl O
2002-01-01
We investigate the laws that rule the behavior of the largest Lyapunov exponent (LLE) in many particle systems with long-range interactions. We consider as a representative system the so-called Hamiltonian alpha-XY model where the adjustable parameter alpha controls the range of the interactions of N ferromagnetic spins in a lattice of dimension d. In previous work the dependence of the LLE with the system size N, for sufficiently high energies, was established through numerical simulations. In the thermodynamic limit, the LLE becomes constant for alpha>d whereas it decays as an inverse power law of N for alpha
Turek, Marko; Spehner, Dominique; Müller, Sebastian; Richter, Klaus
2005-01-01
We present a semiclassical calculation of the generalized form factor Kab(tau) which characterizes the fluctuations of matrix elements of the operators a and b in the eigenbasis of the Hamiltonian of a chaotic system. Our approach is based on some recently developed techniques for the spectral form factor of systems with hyperbolic and ergodic underlying classical dynamics and f = 2 degrees of freedom, that allow us to go beyond the diagonal approximation. First we extend these techniques to systems with f > 2. Then we use these results to calculate Kab(tau). We show that the dependence on the rescaled time tau (time in units of the Heisenberg time) is universal for both the spectral and the generalized form factor. Furthermore, we derive a relation between Kab(tau) and the classical time-correlation function of the Weyl symbols of a and b.
Accurate potential energy functions, non-adiabatic and spin-orbit couplings in the ZnH(+) system.
Liang, Guiying; Liu, Xiaoting; Zhang, Xiaomei; Xu, Haifeng; Yan, Bing
2016-03-05
A high-level ab initio calculation on the ZnH(+) cation has been carried out with the multi-reference configuration interaction method plus Davison correction (MRCI+Q). The scalar relativistic effect is included by using the Douglas-Kroll-Hess (DKH) method. The calculated potential energy curves (PECs) of the 7 Λ-S states are associated with the dissociation limits of Zn(+)((2)Sg)+H((2)Sg), Zn((1)Sg)+H(+)((1)Sg), and Zn(+)((2)Pu)+H((2)Sg), respectively (The Λ-S state is labeled as (2S+1)Λ, in which Λ is the quantum number for the projection along the internuclear axis of the total electronic orbital angular momentum and S is the total electron spin). The spectroscopic constants of the bound states are determined and in good agreement with the available theoretical and experimental results. The permanent dipole moments (PDMs) of Λ-S states and the spin-orbit (SO) matrix elements between Λ-S states are also computed. The results show that the abrupt changes of the PDMs and SO matrix elements come into being for the reason of the avoided crossing between the states with the same symmetry. In addition, the non-adiabatic couplings matrix elements between Λ-S states are also evaluated. Finally, the spin-orbit couplings (SOCs) for the low-lying states are considered with Breit-Pauli operator. The SOC effect makes the 7 Λ-S states of the ZnH(+) cation split into 12 Ω states (Ω=Λ+Sz, in which Sz is projection of the total electron spin S along the internuclear Z-axis). For the (3)0(+) state, the two energy minima exhibit in the potential, which could be attributed to the formation of the new avoided crossing point. The transition dipole moments (TDMs), Franck-Condon factors, and the radiative lifetimes of the selected transitions (2)0(+)-X0(+), (3)0(+)-X0(+), (2)1-X0(+) and (3)1-X0(+) have been reported.
Accurate potential energy functions, non-adiabatic and spin-orbit couplings in the ZnH+ system
NASA Astrophysics Data System (ADS)
Liang, Guiying; Liu, Xiaoting; Zhang, Xiaomei; Xu, Haifeng; Yan, Bing
2016-03-01
A high-level ab initio calculation on the ZnH+ cation has been carried out with the multi-reference configuration interaction method plus Davison correction (MRCI + Q). The scalar relativistic effect is included by using the Douglas-Kroll-Hess (DKH) method. The calculated potential energy curves (PECs) of the 7 Λ-S states are associated with the dissociation limits of Zn+(2Sg) + H(2Sg), Zn(1Sg) + H+(1Sg), and Zn+(2Pu) + H(2Sg), respectively (The Λ-S state is labeled as 2S + 1Λ, in which Λ is the quantum number for the projection along the internuclear axis of the total electronic orbital angular momentum and S is the total electron spin). The spectroscopic constants of the bound states are determined and in good agreement with the available theoretical and experimental results. The permanent dipole moments (PDMs) of Λ-S states and the spin-orbit (SO) matrix elements between Λ-S states are also computed. The results show that the abrupt changes of the PDMs and SO matrix elements come into being for the reason of the avoided crossing between the states with the same symmetry. In addition, the non-adiabatic couplings matrix elements between Λ-S states are also evaluated. Finally, the spin-orbit couplings (SOCs) for the low-lying states are considered with Breit-Pauli operator. The SOC effect makes the 7 Λ-S states of the ZnH+ cation split into 12 Ω states (Ω = Λ + Sz, in which Sz is projection of the total electron spin S along the internuclear Z-axis). For the (3)0+ state, the two energy minima exhibit in the potential, which could be attributed to the formation of the new avoided crossing point. The transition dipole moments (TDMs), Franck-Condon factors, and the radiative lifetimes of the selected transitions (2)0+-X0+, (3)0+-X0+, (2)1-X0+ and (3)1-X0+ have been reported.
Fang, Wanping; Meinhardt, Lyndel W; Mischke, Sue; Bellato, Cláudia M; Motilal, Lambert; Zhang, Dapeng
2014-01-15
Cacao (Theobroma cacao L.), the source of cocoa, is an economically important tropical crop. One problem with the premium cacao market is contamination with off-types adulterating raw premium material. Accurate determination of the genetic identity of single cacao beans is essential for ensuring cocoa authentication. Using nanofluidic single nucleotide polymorphism (SNP) genotyping with 48 SNP markers, we generated SNP fingerprints for small quantities of DNA extracted from the seed coat of single cacao beans. On the basis of the SNP profiles, we identified an assumed adulterant variety, which was unambiguously distinguished from the authentic beans by multilocus matching. Assignment tests based on both Bayesian clustering analysis and allele frequency clearly separated all 30 authentic samples from the non-authentic samples. Distance-based principle coordinate analysis further supported these results. The nanofluidic SNP protocol, together with forensic statistical tools, is sufficiently robust to establish authentication and to verify gourmet cacao varieties. This method shows significant potential for practical application.
2012-01-01
In the present work, the characterization of cobalt-porous silicon (Co-PSi) hybrid systems is performed by a combination of magnetic, spectroscopic, and structural techniques. The Co-PSi structures are composed by a columnar matrix of PSi with Co nanoparticles embedded inside, as determined by Transmission Electron Microscopy (TEM). The oxidation state, crystalline structure, and magnetic behavior are determined by X-Ray Absorption Spectroscopy (XAS) and Alternating Gradient Field Magnetometry (AGFM). Additionally, the Co concentration profile inside the matrix has been studied by Rutherford Backscattering Spectroscopy (RBS). It is concluded that the PSi matrix can be tailored to provide the Co nanoparticles with extra protection against oxidation. PMID:22938050
Cwik, T.; Katz, D.S.
1996-12-31
Finite element modeling has proven useful for accurately simulating scattered or radiated electromagnetic fields from complex three-dimensional objects whose geometry varies on the scale of a fraction of an electrical wavelength. An unstructured finite element model of realistic objects leads to a large, sparse, system of equations that needs to be solved efficiently with regard to machine memory and execution time. Both factorization and iterative solvers can be used to produce solutions to these systems of equations. Factorization leads to high memory requirements that limit the electrical problem size of three-dimensional objects that can be modeled. An iterative solver can be used to efficiently solve the system without excessive memory use and in a minimal amount of time if the convergence rate is controlled.
NASA Technical Reports Server (NTRS)
Golomidov, Y. V.; Li, S. K.; Popov, S. A.; Smolov, V. B.
1986-01-01
After a classification and analysis of electronic and optoelectronic switching devices, the design principles and structure of a matrix optical switch is described. The switching and pair-exclusion operations in this type of switch are examined, and a method for the optical switching of communication channels is elaborated. Finally, attention is given to the structural organization of a parallel computer system with a matrix optical switch.
RF Plasma Torch System for Metal Matrix Composite Production in Nuclear Fuel Cladding
NASA Astrophysics Data System (ADS)
Holik, Eddie, III
2007-10-01
For the first time in 30 years, plans are afoot to build new fission power plants in the US. It is timely to develop technology that could improve the safety and efficiency of new reactors. A program of development for advanced fuel cycles and Generation IV reactors is underway. The path to greater efficiency is to increase the core operating temperature. That places particular challenges to the cladding tubes that contain the fission fuel. A promising material for this purpose is a metal matrix composite (MMC) in which ceramic fibers are bonded within a high-strength steel matrix, much like fiberglass. Current MMC technology lacks the ability to effectively bond traditional high-temperature alloys to ceramic strands. The purpose of this project is to design an rf plasma torch system to use titanium as a buffer between the ceramic fibers and the refractory outer material. The design and methods of using an rf plasma torch to produce a non-equilibrium phase reaction to bond together the MMC will be discussed. The effects of having a long lived fuel cladding in the design of future reactors will also be discussed.
Novaes, Marcel
2015-06-15
We consider the statistics of time delay in a chaotic cavity having M open channels, in the absence of time-reversal invariance. In the random matrix theory approach, we compute the average value of polynomial functions of the time delay matrix Q = − iħS{sup †}dS/dE, where S is the scattering matrix. Our results do not assume M to be large. In a companion paper, we develop a semiclassical approximation to S-matrix correlation functions, from which the statistics of Q can also be derived. Together, these papers contribute to establishing the conjectured equivalence between the random matrix and the semiclassical approaches.
Zetlaoui, Mélanie; Feinberg, Max; Verger, Philippe; Clémençon, Stephan
2011-12-01
In Western countries where food supply is satisfactory, consumers organize their diets around a large combination of foods. It is the purpose of this article to examine how recent nonnegative matrix factorization (NMF) techniques can be applied to food consumption data to understand these combinations. Such data are nonnegative by nature and of high dimension. The NMF model provides a representation of consumption data through latent vectors with nonnegative coefficients, that we call consumption systems (CS), in a small number. As the NMF approach may encourage sparsity of the data representation produced, the resulting CS are easily interpretable. Beyond the illustration of its properties we provide through a simple simulation result, the NMF method is applied to data issued from a French consumption survey. The numerical results thus obtained are displayed and thoroughly discussed. A clustering based on the k-means method is also achieved in the resulting latent consumption space, to recover food consumption patterns easily usable for nutritionists.
Boothroyd, A.I. ); Dove, J.E.; Keogh, W.J. ); Martin, P.G. ); Peterson, M.R. )
1991-09-15
The interaction potential energy surface (PES) of H{sub 4} is of great importance for quantum chemistry, as a test case for molecule--molecule interactions. It is also required for a detailed understanding of certain astrophysical processes, namely, collisional excitation and dissociation of H{sub 2} in molecular clouds, at densities too low to be accessible experimentally. Accurate {ital ab} {ital initio} energies were computed for 6046 conformations of H{sub 4}, using a multiple reference (single and) double excitation configuration interaction (MRD-CI) program. Both systematic and random'' errors were estimated to have an rms size of 0.6 mhartree, for a total rms error of about 0.9 mhartree (or 0.55 kcal/mol) in the final {ital ab} {ital initio} energy values. It proved possible to include in a self-consistent way {ital ab} {ital initio} energies calculated by Schwenke, bringing the number of H{sub 4} conformations to 6101. {ital Ab} {ital initio} energies were also computed for 404 conformations of H{sub 3}; adding {ital ab} {ital initio} energies calculated by other authors yielded a total of 772 conformations of H{sub 3}. (The H{sub 3} results, and an improved analytic PES for H{sub 3}, are reported elsewhere.) {ital Ab} {ital initio} energies are tabulated in this paper only for a sample of H{sub 4} conformations; a full list of all 6101 conformations of H{sub 4} (and 772 conformations of H{sub 3} ) is available from Physics Auxiliary Publication Service (PAPS), or from the authors.
Matrix light and pixel light: optical system architecture and requirements to the light source
NASA Astrophysics Data System (ADS)
Spinger, Benno; Timinger, Andreas L.
2015-09-01
Modern Automotive headlamps enable improved functionality for more driving comfort and safety. Matrix or Pixel light headlamps are not restricted to either pure low beam functionality or pure high beam. Light in direction of oncoming traffic is selectively switched of, potential hazard can be marked via an isolated beam and the illumination on the road can even follow a bend. The optical architectures that enable these advanced functionalities are diverse. Electromechanical shutters and lens units moved by electric motors were the first ways to realize these systems. Switching multiple LED light sources is a more elegant and mechanically robust solution. While many basic functionalities can already be realized with a limited number of LEDs, an increasing number of pixels will lead to more driving comfort and better visibility. The required optical system needs not only to generate a desired beam distribution with a high angular dynamic, but also needs to guarantee minimal stray light and cross talk between the different pixels. The direct projection of the LED array via a lens is a simple but not very efficient optical system. We discuss different optical elements for pre-collimating the light with minimal cross talk and improved contrast between neighboring pixels. Depending on the selected optical system, we derive the basic light source requirements: luminance, surface area, contrast, flux and color homogeneity.
NASA Technical Reports Server (NTRS)
Hanks, Brantley R.; Skelton, Robert E.
1991-01-01
Vibration in modern structural and mechanical systems can be reduced in amplitude by increasing stiffness, redistributing stiffness and mass, and/or adding damping if design techniques are available to do so. Linear Quadratic Regulator (LQR) theory in modern multivariable control design, attacks the general dissipative elastic system design problem in a global formulation. The optimal design, however, allows electronic connections and phase relations which are not physically practical or possible in passive structural-mechanical devices. The restriction of LQR solutions (to the Algebraic Riccati Equation) to design spaces which can be implemented as passive structural members and/or dampers is addressed. A general closed-form solution to the optimal free-decay control problem is presented which is tailored for structural-mechanical system. The solution includes, as subsets, special cases such as the Rayleigh Dissipation Function and total energy. Weighting matrix selection is a constrained choice among several parameters to obtain desired physical relationships. The closed-form solution is also applicable to active control design for systems where perfect, collocated actuator-sensor pairs exist.
NASA Astrophysics Data System (ADS)
Mita, Akira
2016-04-01
The importance of the structural health monitoring system for tall buildings is now widely recognized by at least structural engineers and managers at large real estate companies to ensure the structural safety immediately after a large earthquake and appeal the quantitative safety of buildings to potential tenants. Some leading real estate companies decided to install the system into all tall buildings. Considering this tendency, a pilot project for the west area of Shinjuku Station supported by the Japan Science and Technology Agency was started by the author team to explore a possibility of using the system to provide safe spaces for commuters and residents. The system was installed into six tall buildings. From our experience, it turned out that viewing only from technological aspects was not sufficient for the system to be accepted and to be really useful. Safe spaces require not only the structural safety but also the soundness of key functions of the building. We need help from social scientists, medical doctors, city planners etc. to further improve the integrity of the system.
Akhlaghi, Maryam; Steiner, Tobias; Meka, Sai Ramudu; Mittemeijer, Eric Jan
2016-01-01
Elastic accommodation of precipitation-induced or thermally induced misfit leads to lattice-parameter changes in crystalline multi-phase systems. Formulae for calculation of such misfit-induced lattice-parameter changes are presented for the aggregate (matrix + second-phase particles) and for the individual matrix and second phase, recognizing the occurrence of either coherent or incoherent diffraction by the matrix and second-phase particles. An overview and an (re)interpretation on the above basis is presented of published lattice-parameter data, obtained by X-ray diffraction analyses of aggregates of matrix plus second-phase particles. Examples for three types of systems consisting of a matrix with misfitting second-phase particles are dealt with, which differ in the origin of the misfit (precipitation or thermally induced) and in the type of diffraction (coherent or incoherent diffraction of matrix plus second-phase particles). The experimental data are shown to be in good to very good agreement with predictions according to the current treatment. PMID:26937236
Yuan, Xuebing; Yu, Shuai; Zhang, Shengzhi; Wang, Guoping; Liu, Sheng
2015-01-01
Inertial navigation based on micro-electromechanical system (MEMS) inertial measurement units (IMUs) has attracted numerous researchers due to its high reliability and independence. The heading estimation, as one of the most important parts of inertial navigation, has been a research focus in this field. Heading estimation using magnetometers is perturbed by magnetic disturbances, such as indoor concrete structures and electronic equipment. The MEMS gyroscope is also used for heading estimation. However, the accuracy of gyroscope is unreliable with time. In this paper, a wearable multi-sensor system has been designed to obtain the high-accuracy indoor heading estimation, according to a quaternion-based unscented Kalman filter (UKF) algorithm. The proposed multi-sensor system including one three-axis accelerometer, three single-axis gyroscopes, one three-axis magnetometer and one microprocessor minimizes the size and cost. The wearable multi-sensor system was fixed on waist of pedestrian and the quadrotor unmanned aerial vehicle (UAV) for heading estimation experiments in our college building. The results show that the mean heading estimation errors are less 10° and 5° to multi-sensor system fixed on waist of pedestrian and the quadrotor UAV, respectively, compared to the reference path. PMID:25961384
Yuan, Xuebing; Yu, Shuai; Zhang, Shengzhi; Wang, Guoping; Liu, Sheng
2015-05-07
Inertial navigation based on micro-electromechanical system (MEMS) inertial measurement units (IMUs) has attracted numerous researchers due to its high reliability and independence. The heading estimation, as one of the most important parts of inertial navigation, has been a research focus in this field. Heading estimation using magnetometers is perturbed by magnetic disturbances, such as indoor concrete structures and electronic equipment. The MEMS gyroscope is also used for heading estimation. However, the accuracy of gyroscope is unreliable with time. In this paper, a wearable multi-sensor system has been designed to obtain the high-accuracy indoor heading estimation, according to a quaternion-based unscented Kalman filter (UKF) algorithm. The proposed multi-sensor system including one three-axis accelerometer, three single-axis gyroscopes, one three-axis magnetometer and one microprocessor minimizes the size and cost. The wearable multi-sensor system was fixed on waist of pedestrian and the quadrotor unmanned aerial vehicle (UAV) for heading estimation experiments in our college building. The results show that the mean heading estimation errors are less 10° and 5° to multi-sensor system fixed on waist of pedestrian and the quadrotor UAV, respectively, compared to the reference path.
NASA Astrophysics Data System (ADS)
van Meer, R.; Gritsenko, O. V.; Baerends, E. J.
2014-01-01
Time dependent density matrix functional theory in its adiabatic linear response formulation delivers exact excitation energies ωα and oscillator strengths fα for two-electron systems if extended to the so-called phase including natural orbital (PINO) theory. The Löwdin-Shull expression for the energy of two-electron systems in terms of the natural orbitals and their phases affords in this case an exact phase-including natural orbital functional (PILS), which is non-primitive (contains other than just J and K integrals). In this paper, the extension of the PILS functional to N-electron systems is investigated. With the example of an elementary primitive NO functional (BBC1) it is shown that current density matrix functional theory ground state functionals, which were designed to produce decent approximations to the total energy, fail to deliver a qualitatively correct structure of the (inverse) response function, due to essential deficiencies in the reconstruction of the two-body reduced density matrix (2RDM). We now deduce essential features of an N-electron functional from a wavefunction Ansatz: The extension of the two-electron Löwdin-Shull wavefunction to the N-electron case informs about the phase information. In this paper, applications of this extended Löwdin-Shull (ELS) functional are considered for the simplest case, ELS(1): one (dissociating) two-electron bond in the field of occupied (including core) orbitals. ELS(1) produces high quality ωα(R) curves along the bond dissociation coordinate R for the molecules LiH, Li2, and BH with the two outer valence electrons correlated. All of these results indicate that response properties are much more sensitive to deficiencies in the reconstruction of the 2RDM than the ground state energy, since derivatives of the functional with respect to both the NOs and the occupation numbers need to be accurate.
NASA Astrophysics Data System (ADS)
Kraft, T.; Geßner, M.; Meißner, H.; Przybilla, H. J.; Gerke, M.
2016-03-01
In this paper we present the evaluation of DLR's modular airborne camera system MACS-Micro for remotely piloted aircraft system (RPAS) with a maximum takeoff weight (MTOW) less than 5kg. The main focus is on standardized calibration and test procedures as well as on standardized photogrammetric workflows as a proof of feasibility for this aerial camera concept. The prototype consists of an industrial grade frame imaging camera and a compact GNSS/IMU solution which are operated by an embedded PC. The camera has been calibrated pre- and post- flight using a three dimensional test field. The validation of the latest prototype is done by a traditional photogrammetric evaluation of an aerial survey using 39 ground control points. The results, concerning geometric and radiometric features of the present system concept as well as the quality of the aero triangulation, fulfill many of the aimed keyspecifications.
NASA Astrophysics Data System (ADS)
Gorbachev, Alexey A.; Serikova, Mariya G.; Pantyushina, Ekaterina N.; Volkova, Daria A.
2016-04-01
Modern demands for railway track measurements require high accuracy (about 2-5 mm) of rails placement along the track to ensure smooth, safe and fast transportation. As a mean for railways geometry measurements we suggest a stereoscopic system which measures 3D position of fiducial marks arranged along the track by image processing algorithms. The system accuracy was verified during laboratory tests by comparison with precise laser tracker indications. The accuracy of +/-1.5 mm within a measurement volume 150×400×5000 mm was achieved during the tests. This confirmed that the stereoscopic system demonstrates good measurement accuracy and can be potentially used as fully automated mean for railway track inspection.
Huntington, Lee M J; Hansen, Andreas; Neese, Frank; Nooijen, Marcel
2012-02-14
We have recently introduced a parameterized coupled-cluster singles and doubles model (pCCSD(α, β)) that consists of a bivariate parameterization of the CCSD equations and is inspired by the coupled electron pair approximations. In our previous work, it was demonstrated that the pCCSD(-1, 1) method is an improvement over CCSD for the calculation of geometries, harmonic frequencies, and potential energy surfaces for single bond-breaking. In this paper, we find suitable pCCSD parameters for applications in reaction thermochemistry and thermochemical kinetics. The motivation is to develop an accurate and economical methodology that, when coupled with a robust local correlation framework based on localized pair natural orbitals, is suitable for large-scale thermochemical applications for sizeable molecular systems. It is demonstrated that the original pCCSD(-1, 1) method and several other pCCSD methods are a significant improvement upon the standard CCSD approach and that these methods often approach the accuracy of CCSD(T) for the calculation of reaction energies and barrier heights. We also show that a local version of the pCCSD methodology, implemented within the local pair natural orbital (LPNO) based CCSD code in ORCA, is sufficiently accurate for wide-scale chemical applications. The LPNO based methodology allows us for routine applications to intermediate sized (20-100 atoms) molecular systems and is a significantly more accurate alternative to MP2 and density functional theory for the prediction of reaction energies and barrier heights.
NASA Astrophysics Data System (ADS)
Liang, Bin; Gunawan, Erry; Law, Choi Look; Teh, Kah Chan
Analytical expressions based on the Gauss-Chebyshev quadrature (GCQ) rule technique are derived to evaluate the bit-error rate (BER) for the time-hopping pulse position modulation (TH-PPM) ultra-wide band (UWB) systems under a Nakagami-m fading channel. The analyses are validated by the simulation results and adopted to assess the accuracy of the commonly used Gaussian approximation (GA) method. The influence of the fading severity on the BER performance of TH-PPM UWB system is investigated.
Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi
2013-07-15
Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class.
Lang, Andrew; Stanton, Douglas; Parthasarathy, Vijay; Jain, Ameet
2010-01-01
Cardiovascular disease affects millions of Americans each year. Interventional guidance systems are being developed as treatment options for some of the more delicate procedures, including targeted stem cell therapy. As advanced systems for such types of interventional guidance are being developed, electromagnetic (EM) tracking is coming in demand to perform navigation. To use this EM tracking technology, a calibration is necessary to register the tracker to the imaging system. In this paper we investigate the calibration of an X-ray imaging system to EM tracking. Two specially designed calibration phantoms have been designed for this purpose, each having a rigidly attached EM sensor. From a clinical usability point-of-view, we propose to divide this calibration problem into two steps: i) in initial calibration of the EM sensor to the phantom design using an EM tracked needle to trace out grooves in the phantom surface and ii) segmentation from X-ray images and 3D reconstruction of beads embedded in the phantom in a known geometric pattern. Combining these two steps yields and X-ray-to-EM calibration accuracy of less than 1 mm when overlaying an EM tracked needle on X-ray images.
Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi
2013-07-01
Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class.
NASA Astrophysics Data System (ADS)
Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi
2013-07-01
Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class.
PID controller design for output PDFs of stochastic systems using linear matrix inequalities.
Guo, Lei; Wang, Hong
2005-02-01
This paper presents a pseudo proportional-integral-derivative (PID) tracking control strategy for general non-Gaussian stochastic systems based on a linear B-spline model for the output probability density functions (PDFs). The objective is to control the conditional PDFs of the system output to follow a given target function. Different from existing methods, the control structure (i.e., the PID) is imposed before the output PDF controller design. Following the linear B-spline approximation on the measured output PDFs, the concerned problem is transferred into the tracking of given weights which correspond to the desired PDF. For systems with or without model uncertainties, it is shown that the solvability can be casted into a group of matrix inequalities. Furthermore, an improved controller design procedure based on the convex optimization is proposed which can guarantee the required tracking convergence with an enhanced robustness. Simulations are given to demonstrate the efficiency of the proposed approach and encouraging results have been obtained.
Eigenvalue density of linear stochastic dynamical systems: A random matrix approach
NASA Astrophysics Data System (ADS)
Adhikari, S.; Pastur, L.; Lytova, A.; Du Bois, J.
2012-02-01
Eigenvalue problems play an important role in the dynamic analysis of engineering systems modeled using the theory of linear structural mechanics. When uncertainties are considered, the eigenvalue problem becomes a random eigenvalue problem. In this paper the density of the eigenvalues of a discretized continuous system with uncertainty is discussed by considering the model where the system matrices are the Wishart random matrices. An analytical expression involving the Stieltjes transform is derived for the density of the eigenvalues when the dimension of the corresponding random matrix becomes asymptotically large. The mean matrices and the dispersion parameters associated with the mass and stiffness matrices are necessary to obtain the density of the eigenvalues in the frameworks of the proposed approach. The applicability of a simple eigenvalue density function, known as the Marenko-Pastur (MP) density, is investigated. The analytical results are demonstrated by numerical examples involving a plate and the tail boom of a helicopter with uncertain properties. The new results are validated using an experiment on a vibrating plate with randomly attached spring-mass oscillators where 100 nominally identical samples are physically created and individually tested within a laboratory framework.
NASA Astrophysics Data System (ADS)
Micha, David A.
This contribution deals with two approaches for localized phenomena in excited many-atom systems. The first approach develops a quantum quasi-classical treatment for the density operator, including all atoms. It is based on a partial Wigner representation and is illustrated with applications to photodissociation of NaI, and to light emission of excited Li interacting with a He cluster. This second application describes the direct dynamics with a time-dependent electronic density matrix, expanded in a basis set of atomic functions. It shows that such an approach can deal with electronically excited many-atom systems involving tens of quantum states and hundreds of classical variables. The second approach makes use of the reduced density operator description for a system in a medium. This allows for dissipative dynamics, which can be instantaneous or delayed. An application is presented for femtosecond photodesorption using a Markovian dissipation and construction of the density operator from density amplitudes, for CO/Cu(001). A second application of a reduced density operator has been made to vibrational relaxation of adsorbates, solving integrodifferential equations to compare delayed, instantaneous, and Markovian dissipation. It is concluded that delayed dissipation is needed at short times and that a Markovian treatment is suitable for the interpretation of cross-sectional measurements that involve long-term dynamics.
Diameter-defined Strahler system and connectivity matrix of the pulmonary arterial tree.
Jiang, Z L; Kassab, G S; Fung, Y C
1994-02-01
For modeling of a vascular tree for hemodynamic analysis, the well-known Weibel, Horsfield, and Strahler systems have three shortcomings: vessels of the same order are all treated as in parallel, despite the fact that some are connected in series; histograms of the diameters of vessels in the successive orders have wide overlaps; and the "small-twigs-on-large-trunks" phenomenon is not given a quantitative expression. To improve the accuracy of the hemodynamic circuit model, we made a distinction between vessel segments and vessel elements: a segment is a vessel between two successive nodes of bifurcation; an element is a union of a group of segments of the same order that are connected in series. In an equivalent circuit, all elements of the same order are considered as arranged in parallel. Then, we follow the ordering method of Horsfield and Strahler, with introduction of an additional rule for the assignment of order numbers. If Dn and SDn denote the mean and standard deviation of the diameters of vessels of order n, then our rule divides the gap between Dn--SDn and Dn--1 + SDn--1 evenly between orders n and n--1. Finally, we introduced a connectivity matrix with a component in the mth row and the nth column that is the average number of vessels of order m that grow out of the vessels of order n. This method was applied to the rat. We found that the rat pulmonary arterial tree has 11 orders of vessels and that the geometry is fractal within these orders. The ratios of diameters, lengths, and numbers of elements in successive orders are 1.58, 1.60, and 2.76, respectively. The connectivity matrix reveals interesting features beyond the fractal concept. New features are found in the variation of the total cross-sectional area of elements with order numbers.
Galler, Patrick; Limbeck, Andreas; Boulyga, Sergei F; Stingeder, Gerhard; Hirata, Takafumi; Prohaska, Thomas
2007-07-01
This work introduces a newly developed on-line flow injection (FI) Sr/Rb separation method as an alternative to the common, manual Sr/matrix batch separation procedure, since total analysis time is often limited by sample preparation despite the fast rate of data acquisition possible by inductively coupled plasma-mass spectrometers (ICPMS). Separation columns containing approximately 100 muL of Sr-specific resin were used for on-line FI Sr/matrix separation with subsequent determination of (87)Sr/(86)Sr isotope ratios by multiple collector ICPMS. The occurrence of memory effects exhibited by the Sr-specific resin, a major restriction to the repetitive use of this costly material, could successfully be overcome. The method was fully validated by means of certified reference materials. A set of two biological and six geological Sr- and Rb-bearing samples was successfully characterized for its (87)Sr/(86)Sr isotope ratios with precisions of 0.01-0.04% 2 RSD (n = 5-10). Based on our measurements we suggest (87)Sr/(86)Sr isotope ratios of 0.713 15 +/- 0.000 16 (2 SD) and 0.709 31 +/- 0.000 06 (2 SD) for the NIST SRM 1400 bone ash and the NIST SRM 1486 bone meal, respectively. Measured (87)Sr/(86)Sr isotope ratios for five basalt samples are in excellent agreement with published data with deviations from the published value ranging from 0 to 0.03%. A mica sample with a Rb/Sr ratio of approximately 1 was successfully characterized for its (87)Sr/(86)Sr isotope signature to be 0.718 24 +/- 0.000 29 (2 SD) by the proposed method. Synthetic samples with Rb/Sr ratios of up to 10/1 could successfully be measured without significant interferences on mass 87, which would otherwise bias the accuracy and uncertainty of the obtained data.
Kiupel, M; Webster, J D; Bailey, K L; Best, S; DeLay, J; Detrisac, C J; Fitzgerald, S D; Gamble, D; Ginn, P E; Goldschmidt, M H; Hendrick, M J; Howerth, E W; Janovitz, E B; Langohr, I; Lenz, S D; Lipscomb, T P; Miller, M A; Misdorp, W; Moroff, S; Mullaney, T P; Neyens, I; O'Toole, D; Ramos-Vara, J; Scase, T J; Schulman, F Y; Sledge, D; Smedley, R C; Smith, K; W Snyder, P; Southorn, E; Stedman, N L; Steficek, B A; Stromberg, P C; Valli, V E; Weisbrode, S E; Yager, J; Heller, J; Miller, R
2011-01-01
Currently, prognostic and therapeutic determinations for canine cutaneous mast cell tumors (MCTs) are primarily based on histologic grade. However, the use of different grading systems by veterinary pathologists and institutional modifications make the prognostic value of histologic grading highly questionable. To evaluate the consistency of microscopic grading among veterinary pathologists and the prognostic significance of the Patnaik grading system, 95 cutaneous MCTs from 95 dogs were graded in a blinded study by 28 veterinary pathologists from 16 institutions. Concordance among veterinary pathologists was 75% for the diagnosis of grade 3 MCTs and less than 64% for the diagnosis of grade 1 and 2 MCTs. To improve concordance among pathologists and to provide better prognostic significance, a 2-tier histologic grading system was devised. The diagnosis of high-grade MCTs is based on the presence of any one of the following criteria: at least 7 mitotic figures in 10 high-power fields (hpf); at least 3 multinucleated (3 or more nuclei) cells in 10 hpf; at least 3 bizarre nuclei in 10 hpf; karyomegaly (ie, nuclear diameters of at least 10% of neoplastic cells vary by at least two-fold). Fields with the highest mitotic activity or with the highest degree of anisokaryosis were selected to assess the different parameters. According to the novel grading system, high-grade MCTs were significantly associated with shorter time to metastasis or new tumor development, and with shorter survival time. The median survival time was less than 4 months for high-grade MCTs but more than 2 years for low-grade MCTs.
Yu, Yingting; Yao, Yi; Yan, Hao; Wang, Rui; Zhang, Zhenming; Sun, Xiaodan; Zhao, Lingyun; Ao, Xiang; Xie, Zhen; Wu, Qiong
2016-01-01
Targeted therapy for cancer is a research area of great interest, and magnetic nanoparticles (MNPs) show great potential as targeted carriers for therapeutics. One important class of cancer biomarkers is microRNAs (miRNAs), which play a significant role in tumor initiation and progression. In this study, a cascade recognition system containing multiple plasmids, including a Tet activator, a lacI repressor gene driven by the TetOn promoter, and a reporter gene repressed by the lacI repressor and influenced by multiple endogenous miRNAs, was used to recognize cells that display miRNA signals that are characteristic of cancer. For this purpose, three types of signal miRNAs with high proliferation and metastasis abilities were chosen (miR-21, miR-145, and miR-9). The response of this system to the human breast cancer MCF-7 cell line was 3.2-fold higher than that to the human breast epithelial HBL100 cell line and almost 7.5-fold higher than that to human embryonic kidney HEK293T cells. In combination with polyethyleneimine-modified MNPs, this recognition system targeted the tumor location in situ in an animal model, and an ~42% repression of tumor growth was achieved. Our study provides a new combination of magnetic nanocarrier and gene therapy based on miRNAs that are active in vivo, which has potential for use in future cancer therapies. PMID:27138178
NASA Technical Reports Server (NTRS)
Herrin, Stephanie; Iverson, David; Spukovska, Lilly; Souza, Kenneth A. (Technical Monitor)
1994-01-01
Failure Modes and Effects Analysis contain a wealth of information that can be used to create the knowledge base required for building automated diagnostic Expert systems. A real time monitoring and diagnosis expert system based on an actual NASA project's matrix failure modes and effects analysis was developed. This Expert system Was developed at NASA Ames Research Center. This system was first used as a case study to monitor the Research Animal Holding Facility (RAHF), a Space Shuttle payload that is used to house and monitor animals in orbit so the effects of space flight and microgravity can be studied. The techniques developed for the RAHF monitoring and diagnosis Expert system are general enough to be used for monitoring and diagnosis of a variety of other systems that undergo a Matrix FMEA. This automated diagnosis system was successfully used on-line and validated on the Space Shuttle flight STS-58, mission SLS-2 in October 1993.
McMullen, Allison R.; Wallace, Meghan A.; Pincus, David H.; Wilkey, Kathy
2016-01-01
Invasive fungal infections have a high rate of morbidity and mortality, and accurate identification is necessary to guide appropriate antifungal therapy. With the increasing incidence of invasive disease attributed to filamentous fungi, rapid and accurate species-level identification of these pathogens is necessary. Traditional methods for identification of filamentous fungi can be slow and may lack resolution. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has emerged as a rapid and accurate method for identification of bacteria and yeasts, but a paucity of data exists on the performance characteristics of this method for identification of filamentous fungi. The objective of our study was to evaluate the accuracy of the Vitek MS for mold identification. A total of 319 mold isolates representing 43 genera recovered from clinical specimens were evaluated. Of these isolates, 213 (66.8%) were correctly identified using the Vitek MS Knowledge Base, version 3.0 database. When a modified SARAMIS (Spectral Archive and Microbial Identification System) database was used to augment the version 3.0 Knowledge Base, 245 (76.8%) isolates were correctly identified. Unidentified isolates were subcultured for repeat testing; 71/319 (22.3%) remained unidentified. Of the unidentified isolates, 69 were not in the database. Only 3 (0.9%) isolates were misidentified by MALDI-TOF MS (including Aspergillus amoenus [n = 2] and Aspergillus calidoustus [n = 1]) although 10 (3.1%) of the original phenotypic identifications were not correct. In addition, this methodology was able to accurately identify 133/144 (93.6%) Aspergillus sp. isolates to the species level. MALDI-TOF MS has the potential to expedite mold identification, and misidentifications are rare. PMID:27225405
NASA Astrophysics Data System (ADS)
Díaz-Pinés, E.; Wolf, B.; Kiese, R.; Butterbach-Bahl, K.
2012-04-01
Soils can be either a source or a sink of CH4 and N2O. Accurate assessment of CH4 and N2O soil-atmosphere exchange processes is necessary in order to estimate the contribution of soil to the global warming potential under current and future conditions. Soil-atmosphere exchange processes of both CH4 and N2O depend on a combination of soil temperature and soil moisture status, as well as on nutrient availability and various microbial processes. The task of measuring CH4 and N2O exchange processes is challenging due to, among other factors: high spatial ("hot spots") and temporal heterogeneity ("hot moments") in the emissions of these species. In addition, accurate determination of CH4 and N2O concentrations is still difficult. So far, this prevents from a full understanding and contributes to a high uncertainty degree in the assessment of CH4 and N2O soil-atmosphere exchange rates across different ecosystems. Aiming at the achievement of a deeper understanding of the role of the soil in the GHG balance, we have combined new laser spectroscopy detection techniques (Quantum Cascade Laser, QCL) with automatic and semi-automatic chamber measurement systems. Therefore, different applications will be presented: A three-month-long field campaign in a poplar plantation in NE Romania allowed us to demonstrate the feasibility of the QCL coupled with automatic chambers to accurately estimate the soil-atmosphere GHG exchange at a high time resolution with a very low detection limit. A new semi-automatic system with relatively low human-maintenance requirements was tested in a poplar plantation in SW Germany. The system is not able to record fine-scale temporal variations of the GHG exchange processes; however, cumulative fluxes obtained with the semi-automatic system were very close to those measured with an automatic system with high temporal resolution. Within a climate change experiment in grassland ecosystems, an application of the QCL in combination with a robotized chamber
Zhou, Chunmei; Huang, Shenglei; Shan, Yuzhang; Ye, Xiangru
2014-01-01
Background Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been developed as a new-type soft ionization mass spectrometry in the recent year. Increasing number of clinical microbiological laboratories consider it as an innovate approach for bacterial identification. Methods A total of 876 clinical strains, comprising 52 species in 27 genus, were obtained from Fudan University Affiliated Zhongshan Hospital. We compared the identification accuracy of the Vitek MS system (bioMerieux, Marcy l’Etoile) to other conventional methods for bacterial identification. 16S rRNA gene sequencing was performed as a reference identification method in cases of discrepant results. Results The Vitek MS system consistently produced accurate results within minutes of loading, while conventional methods required several hours to produce identification results. Among the 876 isolates, the overall performance of Vitek MS was significantly better than the conventional method both for correct species identification (830, 94.7% vs. 746, 85.2%, respectively, P=0.000). Conclusions Compared to traditional identification methods, MALDI-TOF MS is a rapid, accurate and economical technique to enhance the clinical value of microorganism identification. PMID:24822117
Nelson, B; Liu, E; Kirby, R M; Haimes, R
2012-12-01
This paper presents the Element Visualizer (ElVis), a new, open-source scientific visualization system for use with high-order finite element solutions to PDEs in three dimensions. This system is designed to minimize visualization errors of these types of fields by querying the underlying finite element basis functions (e.g., high-order polynomials) directly, leading to pixel-exact representations of solutions and geometry. The system interacts with simulation data through runtime plugins, which only require users to implement a handful of operations fundamental to finite element solvers. The data in turn can be visualized through the use of cut surfaces, contours, isosurfaces, and volume rendering. These visualization algorithms are implemented using NVIDIA's OptiX GPU-based ray-tracing engine, which provides accelerated ray traversal of the high-order geometry, and CUDA, which allows for effective parallel evaluation of the visualization algorithms. The direct interface between ElVis and the underlying data differentiates it from existing visualization tools. Current tools assume the underlying data is composed of linear primitives; high-order data must be interpolated with linear functions as a result. In this work, examples drawn from aerodynamic simulations-high-order discontinuous Galerkin finite element solutions of aerodynamic flows in particular-will demonstrate the superiority of ElVis' pixel-exact approach when compared with traditional linear-interpolation methods. Such methods can introduce a number of inaccuracies in the resulting visualization, making it unclear if visual artifacts are genuine to the solution data or if these artifacts are the result of interpolation errors. Linear methods additionally cannot properly visualize curved geometries (elements or boundaries) which can greatly inhibit developers' debugging efforts. As we will show, pixel-exact visualization exhibits none of these issues, removing the visualization scheme as a source of
NASA Astrophysics Data System (ADS)
Liu, Jie; Herbert, John M.
2015-07-01
A novel formulation of time-dependent density functional theory (TDDFT) is derived, based on non-orthogonal, absolutely-localized molecular orbitals (ALMOs). We call this approach TDDFT(MI), in reference to ALMO-based methods for describing molecular interactions (MI) that have been developed for ground-state applications. TDDFT(MI) is intended for efficient excited-state calculations in systems composed of multiple, weakly interacting chromophores. The efficiency is based upon (1) a local excitation approximation; (2) monomer-based, singly-excited basis states; (3) an efficient localization procedure; and (4) a one-step Davidson method to solve the TDDFT(MI) working equation. We apply this methodology to study molecular dimers, water clusters, solvated chromophores, and aggregates of naphthalene diimide that form the building blocks of self-assembling organic nanotubes. Absolute errors of 0.1-0.3 eV with respect to supersystem methods are achievable for these systems, especially for cases involving an excited chromophore that is weakly coupled to several explicit solvent molecules. Excited-state calculations in an aggregate of nine naphthalene diimide monomers are ˜40 times faster than traditional TDDFT calculations.
Liu, Jie; Herbert, John M
2015-07-21
A novel formulation of time-dependent density functional theory (TDDFT) is derived, based on non-orthogonal, absolutely-localized molecular orbitals (ALMOs). We call this approach TDDFT(MI), in reference to ALMO-based methods for describing molecular interactions (MI) that have been developed for ground-state applications. TDDFT(MI) is intended for efficient excited-state calculations in systems composed of multiple, weakly interacting chromophores. The efficiency is based upon (1) a local excitation approximation; (2) monomer-based, singly-excited basis states; (3) an efficient localization procedure; and (4) a one-step Davidson method to solve the TDDFT(MI) working equation. We apply this methodology to study molecular dimers, water clusters, solvated chromophores, and aggregates of naphthalene diimide that form the building blocks of self-assembling organic nanotubes. Absolute errors of 0.1-0.3 eV with respect to supersystem methods are achievable for these systems, especially for cases involving an excited chromophore that is weakly coupled to several explicit solvent molecules. Excited-state calculations in an aggregate of nine naphthalene diimide monomers are ∼40 times faster than traditional TDDFT calculations.
Chowdhury, Amor; Sarjaš, Andrej
2016-09-15
The presented paper describes accurate distance measurement for a field-sensed magnetic suspension system. The proximity measurement is based on a Hall effect sensor. The proximity sensor is installed directly on the lower surface of the electro-magnet, which means that it is very sensitive to external magnetic influences and disturbances. External disturbances interfere with the information signal and reduce the usability and reliability of the proximity measurements and, consequently, the whole application operation. A sensor fusion algorithm is deployed for the aforementioned reasons. The sensor fusion algorithm is based on the Unscented Kalman Filter, where a nonlinear dynamic model was derived with the Finite Element Modelling approach. The advantage of such modelling is a more accurate dynamic model parameter estimation, especially in the case when the real structure, materials and dimensions of the real-time application are known. The novelty of the paper is the design of a compact electro-magnetic actuator with a built-in low cost proximity sensor for accurate proximity measurement of the magnetic object. The paper successively presents a modelling procedure with the finite element method, design and parameter settings of a sensor fusion algorithm with Unscented Kalman Filter and, finally, the implementation procedure and results of real-time operation.
Chowdhury, Amor; Sarjaš, Andrej
2016-01-01
The presented paper describes accurate distance measurement for a field-sensed magnetic suspension system. The proximity measurement is based on a Hall effect sensor. The proximity sensor is installed directly on the lower surface of the electro-magnet, which means that it is very sensitive to external magnetic influences and disturbances. External disturbances interfere with the information signal and reduce the usability and reliability of the proximity measurements and, consequently, the whole application operation. A sensor fusion algorithm is deployed for the aforementioned reasons. The sensor fusion algorithm is based on the Unscented Kalman Filter, where a nonlinear dynamic model was derived with the Finite Element Modelling approach. The advantage of such modelling is a more accurate dynamic model parameter estimation, especially in the case when the real structure, materials and dimensions of the real-time application are known. The novelty of the paper is the design of a compact electro-magnetic actuator with a built-in low cost proximity sensor for accurate proximity measurement of the magnetic object. The paper successively presents a modelling procedure with the finite element method, design and parameter settings of a sensor fusion algorithm with Unscented Kalman Filter and, finally, the implementation procedure and results of real-time operation. PMID:27649197
Crack Driving Forces in a Multilayered Coating System for Ceramic Matrix Composite Substrates
NASA Technical Reports Server (NTRS)
Ghosn, Louis J.; Zhu, Dongming; Miller, Robert A.
2005-01-01
The effects of the top coating thickness, modulus and shrinkage strains on the crack driving forces for a baseline multilayer Yttria-Stabilized-Zirconia/Mullite/Si thermal and environment barrier coating (TEBC) system for SiC/SiC ceramic matrix composite substrates are determined for gas turbine applications. The crack driving forces increase with increasing modulus, and a low modulus thermal barrier coating material (below 10 GPa) will have no cracking issues under the thermal gradient condition analyzed. Since top coating sintering increases the crack driving forces with time, highly sintering resistant coatings are desirable to maintain a low tensile modulus and maintain a low crack driving force with time. Finite element results demonstrated that an advanced TEBC system, such as ZrO2/HfO2, which possesses improved sintering resistance and high temperature stability, exhibited excellent durability. A multi-vertical cracked structure with fine columnar spacing is an ideal strain tolerant coating capable of reducing the crack driving forces to an acceptable level even with a high modulus of 50 GPa.
Suitability of gamma irradiated chitosan based membranes as matrix in drug release system.
Casimiro, M H; Gil, M H; Leal, J P
2010-08-16
To test the possibility of obtain a material simultaneously biocompatible and microbiologically safe to be used as wound dressing material and as a matrix for drug release system, membranes with different initial contents in chitosan and 2-hydroxyethyl methacrylate (HEMA) have been prepared by gamma irradiation from a (60)Co source. The antimicrobial activity of obtained membranes against several reference strains was evaluated after inoculation. Sub-lethal gamma radiation doses were also applied in artificially contaminated membranes and the D(values) of microorganisms in use were determined in order to predict which radiation dose could guarantee membranes microbiological safety. In vitro haemolysis tests were also performed using drug loaded membranes irradiated at different doses. Results point out that those membranes naturally exhibit antimicrobial properties. Also show that, over the studied range values, drug loaded irradiated membranes display a non-significant level of haemolysis. These features show that the application of prepared membranes as a transdermal drug release system "ready to use" is viable.
Mechanics and crack formation in the extracellular matrix with articular cartilage as a model system
NASA Astrophysics Data System (ADS)
Kearns, Sarah; Silverberg, Jesse; Bonassar, Lawrence; Cohen, Itai; Das, Moumita
We investigate the mechanical structure-function relations in the extracellular matrix (ECM) with focus on crack formation and failure. As a model system, our study focuses on the ECM in articular cartilage (AC), the tissue that covers the ends of bones, and distributes load in joints including in the knees, shoulders, and hips. The strength, toughness, and crack resistance of native articular cartilage is unparalleled in materials made by humankind. This mechanical response is mainly due to its ECM. The ECM in AC has two major mechanobiological components: a network of the biopolymer collagen and a flexible aggrecan gel. We model this system as a biopolymer network embedded in a swelling gel, and investigate the conditions for the formation and propagation of cracks using a combination of rigidity percolation theory and energy minimization approaches. Our results may provide useful insights into the design principles of the ECM as well as of biomimetic hydrogels that are mechanically robust and can, at the same time, easily adapt to cues in their surroundings. This work was partially supported by a Cottrell College Science Award.
Reduced-density-matrix spectrum and block entropy of permutationally invariant many-body systems.
Salerno, Mario; Popkov, Vladislav
2010-07-01
Spectral properties of the reduced density matrix (RDM) of permutational invariant quantum many-body systems are investigated. The RDM block diagonalization which accounts for all symmetries of the Hamiltonian is achieved. The analytical expression of the RDM spectrum is provided for arbitrary parameters and rigorously proved in the thermodynamical limit. The existence of several sum rules and recurrence relations among RDM eigenvalues is also demonstrated and the distribution function of RDM eigenvalues (including degeneracies) characterized. In particular, we prove that the distribution function approaches a two-dimensional Gaussian in the limit of large subsystem sizes n>1. As a physical application we discuss the von Neumann entropy (VNE) of a block of size n for a system of hard-core bosons on a complete graph, as a function of n and of the temperature T. The occurrence of a crossover of VNE from purely logarithmic behavior at T=0 to a purely linear behavior in n for T≥Tc, is demonstrated.
Matrix Algebra for GPU and Multicore Architectures (MAGMA) for Large Petascale Systems
Dongarra, Jack J.; Tomov, Stanimire
2014-03-24
The goal of the MAGMA project is to create a new generation of linear algebra libraries that achieve the fastest possible time to an accurate solution on hybrid Multicore+GPU-based systems, using all the processing power that future high-end systems can make available within given energy constraints. Our efforts at the University of Tennessee achieved the goals set in all of the five areas identified in the proposal: 1. Communication optimal algorithms; 2. Autotuning for GPU and hybrid processors; 3. Scheduling and memory management techniques for heterogeneity and scale; 4. Fault tolerance and robustness for large scale systems; 5. Building energy efficiency into software foundations. The University of Tennessee’s main contributions, as proposed, were the research and software development of new algorithms for hybrid multi/many-core CPUs and GPUs, as related to two-sided factorizations and complete eigenproblem solvers, hybrid BLAS, and energy efficiency for dense, as well as sparse, operations. Furthermore, as proposed, we investigated and experimented with various techniques targeting the five main areas outlined.
Samudrala, Ram; Heffron, Fred; McDermott, Jason E.
2009-04-24
The type III secretion system is an essential component for virulence in many Gram-negative bacteria. Though components of the secretion system apparatus are conserved, its substrates, effector proteins, are not. We have used a machine learning approach to identify new secreted effectors. The method integrates evolutionary measures, such as the pattern of homologs in a range of other organisms, and sequence-based features, such as G+C content, amino acid composition and the N-terminal 30 residues of the protein sequence. The method was trained on known effectors from Salmonella typhimurium and validated on a corresponding set of effectors from Pseudomonas syringae, after eliminating effectors with detectable sequence similarity. The method was able to identify all of the known effectors in P. syringae with a specificity of 84% and sensitivity of 82%. The reciprocal validation, training on P. syringae and validating on S. typhimurium, gave similar results with a specificity of 86% when the sensitivity level was 87%. These results show that type III effectors in disparate organisms share common features. We found that maximal performance is attained by including an N-terminal sequence of only 30 residues, which agrees with previous studies indicating that this region contains the secretion signal. We then used the method to define the most important residues in this putative secretion signal. Finally, we present novel predictions of secreted effectors in S. typhimurium, some of which have been experimentally validated, and apply the method to predict secreted effectors in the genetically intractable human pathogen Chlamydia trachomatis. This approach is a novel and effective way to identify secreted effectors in a broad range of pathogenic bacteria for further experimental characterization and provides insight into the nature of the type III secretion signal.
NASA Astrophysics Data System (ADS)
Margaris, G.; Vasilakaki, M.; Peddis, D.; Trohidou, K. N.; Laureti, S.; Binns, C.; Agostinelli, E.; Rinaldi, D.; Mathieu, R.; Fiorani, D.
2017-01-01
In nanoparticle systems consisting of two magnetic materials (bi-magnetic nanoparticles or nanoparticles embedded in a magnetic matrix), there is a constantly growing interest in the investigation of the interplay between interparticle interactions and the nanoparticle-matrix interface exchange coupling, because of its enormous impact on a number of technological applications. The understanding of the mechanisms of such interplay is a great challenge, as it would allow controlling equilibrium and non-equilibrium magnetization dynamics of exchange coupled nanoparticles systems and finely tuning their anisotropy. Here, we provide evidence that this interplay leads to a collective superspin glass (SSG) behavior in a system of diluted ferromagnetic (FM) nanoparticles embedded in an antiferromagnetic (AFM) matrix (5% volume fraction of Co particles in Mn film matrix). We have developed a novel mesoscopic model to study the influence of interparticle interaction on the exchange bias (EB) and the dynamical behavior of assemblies of FM nanoparticles embedded in a granular AFM matrix. Our mesoscopic model is based on reducing the amount of simulated spins to the minimum number necessary to describe the magnetic structure of the system and introducing the adequate exchange parameters between the different spins. The model replicates remarkably well the observed static and dynamical SSG properties as well as the EB behavior. In addition, the proposed model well explains the role of the significant Co/Mn alloying and of the granularity of the matrix in mediating interparticle interactions through exchange and dipole-dipole coupling between the uncompensated moments of its grains and the exchange interaction at the Co/Mn interface.
Arhun, Neslihan; Cehreli, Sevi Burcak
2013-01-01
Reestablishing proximal contacts with composite resins may prove challenging since the applied adhesives may lead to resin coating that produces additional thickness. The aim of this study was to investigate the surface of metal matrix bands after application of adhesive systems and blowing or wiping off the adhesive before polymerization. Seventeen groups of matrix bands were prepared. The remnant particles were characterized by energy dispersive spectrum and scanning electron microscopy. Total etch and two-step self-etch adhesives did not leave any resin residues by wiping and blowing off. All-in-one adhesive revealed resin residues despite wiping off. Prime and Bond NT did not leave any remnant with compomer. Clinicians must be made aware of the consequences of possible adhesive remnants on matrix bands that may lead to a defective definitive restoration. The adhesive resin used for Class II restorations may leave resin coats on metal matrix bands after polymerization, resulting in additional thickness on the metal matrix bands and poor quality of the proximal surface of the definitive restoration when the adhesive system is incorporated in the restoration.
Burnham, Carey-Ann D.; Bythrow, Maureen; Garner, Omai B.; Ginocchio, Christine C.; Jennemann, Rebecca; Lewinski, Michael A.; Manji, Ryhana; Mochon, A. Brian; Procop, Gary W.; Richter, Sandra S.; Sercia, Linda; Westblade, Lars F.; Ferraro, Mary Jane; Branda, John A.
2013-01-01
Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF) is gaining momentum as a tool for bacterial identification in the clinical microbiology laboratory. Compared with conventional methods, this technology can more readily and conveniently identify a wide range of organisms. Here, we report the findings from a multicenter study to evaluate the Vitek MS v2.0 system (bioMérieux, Inc.) for the identification of aerobic Gram-positive bacteria. A total of 1,146 unique isolates, representing 13 genera and 42 species, were analyzed, and results were compared to those obtained by nucleic acid sequence-based identification as the reference method. For 1,063 of 1,146 isolates (92.8%), the Vitek MS provided a single identification that was accurate to the species level. For an additional 31 isolates (2.7%), multiple possible identifications were provided, all correct at the genus level. Mixed-genus or single-choice incorrect identifications were provided for 18 isolates (1.6%). Although no identification was obtained for 33 isolates (2.9%), there was no specific bacterial species for which the Vitek MS consistently failed to provide identification. In a subset of 463 isolates representing commonly encountered important pathogens, 95% were accurately identified to the species level and there were no misidentifications. Also, in all but one instance, the Vitek MS correctly differentiated Streptococcus pneumoniae from other viridans group streptococci. The findings demonstrate that the Vitek MS system is highly accurate for the identification of Gram-positive aerobic bacteria in the clinical laboratory setting. PMID:23658261
Rychert, Jenna; Burnham, Carey-Ann D; Bythrow, Maureen; Garner, Omai B; Ginocchio, Christine C; Jennemann, Rebecca; Lewinski, Michael A; Manji, Ryhana; Mochon, A Brian; Procop, Gary W; Richter, Sandra S; Sercia, Linda; Westblade, Lars F; Ferraro, Mary Jane; Branda, John A
2013-07-01
Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) is gaining momentum as a tool for bacterial identification in the clinical microbiology laboratory. Compared with conventional methods, this technology can more readily and conveniently identify a wide range of organisms. Here, we report the findings from a multicenter study to evaluate the Vitek MS v2.0 system (bioMérieux, Inc.) for the identification of aerobic Gram-positive bacteria. A total of 1,146 unique isolates, representing 13 genera and 42 species, were analyzed, and results were compared to those obtained by nucleic acid sequence-based identification as the reference method. For 1,063 of 1,146 isolates (92.8%), the Vitek MS provided a single identification that was accurate to the species level. For an additional 31 isolates (2.7%), multiple possible identifications were provided, all correct at the genus level. Mixed-genus or single-choice incorrect identifications were provided for 18 isolates (1.6%). Although no identification was obtained for 33 isolates (2.9%), there was no specific bacterial species for which the Vitek MS consistently failed to provide identification. In a subset of 463 isolates representing commonly encountered important pathogens, 95% were accurately identified to the species level and there were no misidentifications. Also, in all but one instance, the Vitek MS correctly differentiated Streptococcus pneumoniae from other viridans group streptococci. The findings demonstrate that the Vitek MS system is highly accurate for the identification of Gram-positive aerobic bacteria in the clinical laboratory setting.
NASA Technical Reports Server (NTRS)
Packard, A. K.; Sastry, S. S.
1986-01-01
A method of solving a class of linear matrix equations over various rings is proposed, using results from linear geometric control theory. An algorithm, successfully implemented, is presented, along with non-trivial numerical examples. Applications of the method to the algebraic control system design methodology are discussed.
Kaethner, Christian; Erb, Wolfgang; Ahlborg, Mandy; Szwargulski, Patryk; Knopp, Tobias; Buzug, Thorsten M
2016-11-01
Magnetic Particle Imaging (MPI) is an emerging technology in the field of (pre)clinical imaging. The acquisition of a particle signal is realized along specific sampling trajectories covering a defined field of view (FOV). In a system matrix (SM) based reconstruction procedure, the commonly used acquisition path in MPI is a Lissajous trajectory. Such a trajectory features an inhomogeneous coverage of the FOV, i.e. the center region is sampled less dense than the regions towards the edges of the FOV. Conventionally, the respective SM acquisition and the subsequent reconstruction do not reflect this inhomogeneous coverage. Instead, they are performed on an equispaced grid. The objective of this work is to introduce a sampling grid that inherently features the aforementioned inhomogeneity by using node points of Lissajous trajectories. Paired with a tailored polynomial interpolation of the reconstructed MPI signal, the entire image can be recovered. It is the first time that such a trajectory related non-equispaced grid is used for image reconstruction on simulated and measured MPI data and it is shown that the number of sampling positions can be reduced, while the spatial resolution remains constant.
Blade system design studies volume II : preliminary blade designs and recommended test matrix.
Griffin, Dayton A.
2004-06-01
As part of the U.S. Department of Energy's Wind Partnerships for Advanced Component Technologies (WindPACT) program, Global Energy Concepts, LLC is performing a Blade System Design Study (BSDS) concerning innovations in materials, processes and structural configurations for application to wind turbine blades in the multi-megawatt range. The BSDS Volume I project report addresses issues and constraints identified to scaling conventional blade designs to the megawatt size range, and evaluated candidate materials, manufacturing and design innovations for overcoming and improving large blade economics. The current report (Volume II), presents additional discussion of materials and manufacturing issues for large blades, including a summary of current trends in commercial blade manufacturing. Specifications are then developed to guide the preliminary design of MW-scale blades. Using preliminary design calculations for a 3.0 MW blade, parametric analyses are performed to quantify the potential benefits in stiffness and decreased gravity loading by replacement of a baseline fiberglass spar with carbon-fiberglass hybrid material. Complete preliminary designs are then presented for 3.0 MW and 5.0 MW blades that incorporate fiberglass-to-carbon transitions at mid-span. Based on analysis of these designs, technical issues are identified and discussed. Finally, recommendations are made for composites testing under Part I1 of the BSDS, and the initial planned test matrix for that program is presented.
Singular-potential random-matrix model arising in mean-field glassy systems.
Akemann, Gernot; Villamaina, Dario; Vivo, Pierpaolo
2014-06-01
We consider an invariant random matrix ensemble where the standard Gaussian potential is distorted by an additional single pole of arbitrary fixed order. Potentials with first- and second-order poles have been considered previously and found applications in quantum chaos and number theory. Here we present an application to mean-field glassy systems. We derive and solve the loop equation in the planar limit for the corresponding class of potentials. We find that the resulting mean or macroscopic spectral density is generally supported on two disconnected intervals lying on the two sides of the repulsive pole, whose edge points can be completely determined imposing the additional constraint of traceless matrices on average. For an unbounded potential with an attractive pole, we also find a possible one-cut solution for certain values of the couplings, which is ruled out when the traceless condition is imposed. Motivated by the calculation of the distribution of the spin-glass susceptibility in the Sherrington-Kirkpatrick spin-glass model, we consider in detail a second-order pole for a zero-trace model and provide the most explicit solution in this case. In the limit of a vanishing pole, we recover the standard semicircle. Working in the planar limit, our results apply to matrices with orthogonal, unitary, and symplectic invariance. Numerical simulations and an independent analytical Coulomb fluid calculation for symmetric potentials provide an excellent confirmation of our results.
Garbuzova, V Yu; Stroy, D A; Dosenko, V E; Dubovyk, Ye I; Borodenko, A O; Shimko, K A; Obukhova, O A; Ataman, O V
2015-01-01
There are results of the determination of 10 polymorphisms of matrix Gla-protein system (gene MGP-T(-138)-->C (rs1800802), G(-7)-->A (rs1800801), Thr83-->Ala (rs4236), gene VDR-FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232), TaqI (rs731236), gene GGCX-Arg325-->Gln (rs699664), gene VKORS1-T(2255)-->C (rs2359612), gene BMP-2-Ser37-->Ala (rs2273073)) into 170 patients with ischemic atherothrombotic stroke (IATS) and 124 healthy individual is (control group). It is established that there is a connection between the IATS and polymorphic variants of genes MGP (G(-7)-->A) and VKORC1 (T(2255)-->C). The risk of IATS in carriers of minor allele A/A (G(-7)-->A polymorphism) in 2.6 times higher than in carriers of the major allele (G/A + G/G), and C/C genotype (T(2255)-->C polymorphism) in 2.2 times higher than the homozygotes of major allele. The coincidence of patients T/C and G/G, C/C and G/A genotypes, and A/A genotype (G(-7)-->A polymorphism) with any genotype T(2255)-->C polymorphism are increases the risk of IATS.
Concentric gel system to study the biophysical role of matrix microenvironment on 3D cell migration.
Kurniawan, Nicholas Agung; Chaudhuri, Parthiv Kant; Lim, Chwee Teck
2015-04-03
The ability of cells to migrate is crucial in a wide variety of cell functions throughout life from embryonic development and wound healing to tumor and cancer metastasis. Despite intense research efforts, the basic biochemical and biophysical principles of cell migration are still not fully understood, especially in the physiologically relevant three-dimensional (3D) microenvironments. Here, we describe an in vitro assay designed to allow quantitative examination of 3D cell migration behaviors. The method exploits the cell's mechanosensing ability and propensity to migrate into previously unoccupied extracellular matrix (ECM). We use the invasion of highly invasive breast cancer cells, MDA-MB-231, in collagen gels as a model system. The spread of cell population and the migration dynamics of individual cells over weeks of culture can be monitored using live-cell imaging and analyzed to extract spatiotemporally-resolved data. Furthermore, the method is easily adaptable for diverse extracellular matrices, thus offering a simple yet powerful way to investigate the role of biophysical factors in the microenvironment on cell migration.
Lukaszewicz-Zając, Marta; Mroczko, Barbara; Kornhuber, Johannes; Lewczuk, Piotr
2014-05-01
Malignant neoplasms of the central nervous system (CNS) account for about 1.3 % of all tumors and 2.2 % of all cancer-related deaths. CNS tumors consist of heterogeneous group of neoplasms, including different variants of primary brain tumors and metastatic neoplasms. Advanced imaging techniques improved the neuroradiological diagnostic accuracy, although these methods are not specific enough for differentiation of CNS tumors, thus new approaches of patients' diagnosis are critically needed. The best solution for the diagnosis of patients with CNS tumors could be easily available biomarkers, which could be useful for the management of CNS neoplasms. Biomarkers should facilitate the diagnosis, monitor of treatment response and assess the prognosis of patients' survival. Currently, except for rare germ cell tumors, there is a lack of knowledge on biochemical markers for CNS neoplasms. Therefore, in this paper we summarized and referred a number of comprehensive reviews concerning the role of matrix metalloproteinases (MMPs) and their tissue inhibitors in tumor progression, including CNS neoplasms as well as described the general biochemistry of MMPs and their tissue inhibitors. Moreover, we presented the wide variety of previous findings, where authors suggested the significance of selected MMPs and their tissue inhibitors as potential biomarkers of human tumors, including CNS tumors. However, future investigations are needed to be performed before some of these enzymes could finally be used as biomarkers of specific types of CNS neoplasms.
Bakun, M; Senatorski, G; Rubel, T; Lukasik, A; Zielenkiewicz, P; Dadlez, M; Paczek, L
2014-02-01
Aging is a complex physiological process that poses considerable conundrums to rapidly aging societies. For example, the risk of dying from cardiovascular diseases and/or cancer steadily declines for people after their 60s, and other causes of death predominate for seniors older than 80 years of age. Thus, physiological aging presents numerous unanswered questions, particularly with regard to changing metabolic patterns. Urine proteomics analysis is becoming a non-invasive and reproducible diagnostic method. We investigated the urine proteomes in healthy elderly people to determine which metabolic processes were weakened or strengthened in aging humans. Urine samples from 37 healthy volunteers aged 19-90 years (19 men, 18 women) were analyzed for protein expression by liquid chromatography-tandem mass spectrometry. This generated a list of 19 proteins that were differentially expressed in different age groups (young, intermediate, and old age). In particular, the oldest group showed protein changes reflective of altered extracellular matrix turnover and declining immune function, in which changes corresponded to reported changes in cardiovascular tissue remodeling and immune disorders in the elderly. Thus, urinary proteome changes in the elderly appear to reflect the physiological processes of aging and are particularly clearly represented in the circulatory and immune systems. Detailed identification of "protein trails" creates a more global picture of metabolic changes that occur in the elderly.
Huang, Hai; Kornberg, Thomas B
2016-01-01
Drosophila dorsal air sac development depends on Decapentaplegic (Dpp) and Fibroblast growth factor (FGF) proteins produced by the wing imaginal disc and transported by cytonemes to the air sac primordium (ASP). Dpp and FGF signaling in the ASP was dependent on components of the planar cell polarity (PCP) system in the disc, and neither Dpp- nor FGF-receiving cytonemes extended over mutant disc cells that lacked them. ASP cytonemes normally navigate through extracellular matrix (ECM) composed of collagen, laminin, Dally and Dally-like (Dlp) proteins that are stratified in layers over the disc cells. However, ECM over PCP mutant cells had reduced levels of laminin, Dally and Dlp, and whereas Dpp-receiving ASP cytonemes navigated in the Dally layer and required Dally (but not Dlp), FGF-receiving ASP cytonemes navigated in the Dlp layer, requiring Dlp (but not Dally). These findings suggest that cytonemes interact directly and specifically with proteins in the stratified ECM. DOI: http://dx.doi.org/10.7554/eLife.18979.001 PMID:27591355
Stabilization of pH in solid-matrix hydroponic systems
NASA Technical Reports Server (NTRS)
Frick, J.; Mitchell, C. A.
1993-01-01
2-[N-morpholino]ethanesulfonic acid (MES) buffer or Amberlite DP-1 (cation-exchange resin beads) were used to stabilize substrate pH of passive-wicking, solid-matrix hydroponic systems in which small canopies of Brassica napus L. (CrGC 5-2, genome : ACaacc) were grown to maturity. Two concentrations of MES (5 or 10 mM) were included in Hoagland 1 nutrient solution. Alternatively, resin beads were incorporated into the 2 vermiculite : 1 perlite (v/v) growth medium at 6% or 12% of total substrate volume. Both strategies stabilized pH without toxic side effects on plants. Average seed yield rates for all four pH stabilization treatments (13.3 to 16.9 g m-2 day-1) were about double that of the control (8.2 g m-2 day-1), for which there was no attempt to buffer substrate pH. Both the highest canopy seed yield rate (16.9 g m-2 day-1) and the highest shoot harvest index (19.5%) occurred with the 6% resin bead treatment, even though the 10 mM MES and 12% bead treatments maintained pH within the narrowest limits. The pH stabilization methods tested did not significantly affect seed oil and protein contents.
Concentric Gel System to Study the Biophysical Role of Matrix Microenvironment on 3D Cell Migration
Kurniawan, Nicholas Agung; Chaudhuri, Parthiv Kant; Lim, Chwee Teck
2015-01-01
The ability of cells to migrate is crucial in a wide variety of cell functions throughout life from embryonic development and wound healing to tumor and cancer metastasis. Despite intense research efforts, the basic biochemical and biophysical principles of cell migration are still not fully understood, especially in the physiologically relevant three-dimensional (3D) microenvironments. Here, we describe an in vitro assay designed to allow quantitative examination of 3D cell migration behaviors. The method exploits the cell’s mechanosensing ability and propensity to migrate into previously unoccupied extracellular matrix (ECM). We use the invasion of highly invasive breast cancer cells, MDA-MB-231, in collagen gels as a model system. The spread of cell population and the migration dynamics of individual cells over weeks of culture can be monitored using live-cell imaging and analyzed to extract spatiotemporally-resolved data. Furthermore, the method is easily adaptable for diverse extracellular matrices, thus offering a simple yet powerful way to investigate the role of biophysical factors in the microenvironment on cell migration. PMID:25867104
Singular-potential random-matrix model arising in mean-field glassy systems
NASA Astrophysics Data System (ADS)
Akemann, Gernot; Villamaina, Dario; Vivo, Pierpaolo
2014-06-01
We consider an invariant random matrix ensemble where the standard Gaussian potential is distorted by an additional single pole of arbitrary fixed order. Potentials with first- and second-order poles have been considered previously and found applications in quantum chaos and number theory. Here we present an application to mean-field glassy systems. We derive and solve the loop equation in the planar limit for the corresponding class of potentials. We find that the resulting mean or macroscopic spectral density is generally supported on two disconnected intervals lying on the two sides of the repulsive pole, whose edge points can be completely determined imposing the additional constraint of traceless matrices on average. For an unbounded potential with an attractive pole, we also find a possible one-cut solution for certain values of the couplings, which is ruled out when the traceless condition is imposed. Motivated by the calculation of the distribution of the spin-glass susceptibility in the Sherrington-Kirkpatrick spin-glass model, we consider in detail a second-order pole for a zero-trace model and provide the most explicit solution in this case. In the limit of a vanishing pole, we recover the standard semicircle. Working in the planar limit, our results apply to matrices with orthogonal, unitary, and symplectic invariance. Numerical simulations and an independent analytical Coulomb fluid calculation for symmetric potentials provide an excellent confirmation of our results.
System and method for the adaptive mapping of matrix data to sets of polygons
NASA Technical Reports Server (NTRS)
Burdon, David (Inventor)
2003-01-01
A system and method for converting bitmapped data, for example, weather data or thermal imaging data, to polygons is disclosed. The conversion of the data into polygons creates smaller data files. The invention is adaptive in that it allows for a variable degree of fidelity of the polygons. Matrix data is obtained. A color value is obtained. The color value is a variable used in the creation of the polygons. A list of cells to check is determined based on the color value. The list of cells to check is examined in order to determine a boundary list. The boundary list is then examined to determine vertices. The determination of the vertices is based on a prescribed maximum distance. When drawn, the ordered list of vertices create polygons which depict the cell data. The data files which include the vertices for the polygons are much smaller than the corresponding cell data files. The fidelity of the polygon representation can be adjusted by repeating the logic with varying fidelity values to achieve a given maximum file size or a maximum number of vertices per polygon.
The effect of an autologous cellular gel-matrix integrated implant system on wound healing
2010-01-01
Background This manuscript reports the production and preclinical studies to examine the tolerance and efficacy of an autologous cellular gel-matrix integrated implant system (IIS) aimed to treat full-thickness skin lesions. Methods The best concentration of fibrinogen and thrombin was experimentally determined by employing 28 formula ratios of thrombin and fibrinogen and checking clot formation and apparent stability. IIS was formed by integrating skin cells by means of the in situ gelification of fibrin into a porous crosslinked scaffold composed of chitosan, gelatin and hyaluronic acid. The in vitro cell proliferation within the IIS was examined by the MTT assay and PCNA expression. An experimental rabbit model consisting of six circular lesions was utilized to test each of the components of the IIS. Then, the IIS was utilized in an animal model to cover a 35% body surface full thickness lesion. Results The preclinical assays in rabbits demonstrated that the IIS was well tolerated and also that IIS-treated rabbit with lesions of 35% of their body surface, exhibited a better survival rate (p = 0,06). Conclusion IIS should be further studied as a new wound dressing which shows promising properties, being the most remarkable its good biological tolerance and cell growth promotion properties. PMID:20565787
NASA Astrophysics Data System (ADS)
Kohout, T.; Pesonen, L. J.
2005-12-01
The Avanhandava (H4) fall occurred in 1952 in Brazil. A total of 9.33 kg had been preserved after the meteorite brake up during the impact [1]. The meteorite contains large (0.1 - 2.0 mm) chon-drules that have clearly delineated boundaries with matrix. This characteristic allows us to pick up oriented individual chondrules and study their magnetic properties. The chondrules of the Avanhandava meteorite show a low and randomly oriented NRM (10-2 - 10-1 mAm2/kg). In contrast the matrix is strongly (100 - 101 mAm2/kg) and uniformly magnet-ized [2]. Various methods for paleofield determination have been applied on matrix and individual chondrules in order to determine possi-ble magnetizing processes and paleofields in early solar systems.. The laboratory experiments reveal approximate paleofields for matrix similar to present geomagnetic field. The paleofield de-termined for chondrules is approximately one order of magnitude lower comparing to values obtained for matrix. That suggests that chondrules are not magnetically contaminated by geomagnetic or artificial fields and they acquired their NRM prior their aggregation to Avanhandava parent body (random NRM directions). The matrix shows remarkable traces of terres-trial weathering and is uniformly magnetized. The paleofield re-sult for matrix indicates possible remagnetization caused by ter-restrial weathering. The terrestrial weathering of ordinary chon-drites is observed even on falls stored in museums and can sig-nificantly influence meteorite magnetic records [3, 4]. References: [1] Paar W. et al. 1976. Revista Brasileira de Geo-ciencias 6: 201-210. [2] Kohout T. and Pesonen L. J. 2005. 68th Annual Meteoritical Society Meeting: 5202. [3] Kohout T. et al. 2004. Physics and Chemistry of the Earth 29: 885-897. [4] Lee M. R. and Bland P. A. 2004. Geochimica et Cosmochimica Acta 68: 893-916.
NASA Astrophysics Data System (ADS)
Brown, Sandra E.; Mandelshtam, Vladimir A.
2016-12-01
The self-consistent phonons (SCP) method is a practical approach for computing structural and dynamical properties of a general quantum or classical many-body system while incorporating anharmonic effects. However, a convincing demonstration of the accuracy of SCP and its advantages over the standard harmonic approximation is still lacking. Here we apply SCP to classical Lennard-Jones (LJ) clusters and compare with numerically exact results. The close agreement between the two reveals that SCP accurately describes structural properties of the classical LJ clusters from zero-temperature (where the method is exact) up to the temperatures at which the chosen cluster conformation becomes unstable. Given the similarities between thermal and quantum fluctuations, both physically and within the SCP ansatz, the accuracy of classical SCP over a range of temperatures suggests that quantum SCP is also accurate over a range of quantum de Boer parameter Λ = ℏ / (σ√{ mε }) , which describes the degree of quantum character of the system.
Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction
Aguiar, Pablo; Pino, Francisco; Silva-Rodríguez, Jesús; Pavía, Javier; Ros, Doménec; Ruibal, Álvaro; and others
2014-03-15
Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approaches on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the
Shakib-Manesh, T.E.; Hirvonen, K.O.; Jalava, K.J.; Ålander, T.; Kuitunen, M.T.
2014-11-15
Environmental impacts of small scale projects are often assessed poorly, or not assessed at all. This paper examines the usability of the Rapid Impact Assessment Matrix (RIAM) as a tool to prioritize project proposals for small scale water restoration projects in relation to proposals' potential to improve the environment. The RIAM scoring system was used to assess and rank the proposals based on their environmental impacts, the costs of the projects to repair the harmful impacts, and the size of human population living around the sites. A four-member assessment group (The expert panel) gave the RIAM-scores to the proposals. The assumed impacts of the studied projects at the Eastern Finland water systems were divided into the ecological and social impacts. The more detailed assessment categories of the ecological impacts in this study were impacts on landscape, natural state, and limnology. The social impact categories were impacts to recreational use of the area, fishing, industry, population, and economy. These impacts were scored according to their geographical and social significance, their magnitude of change, their character, permanence, reversibility, and cumulativeness. The RIAM method proved to be an appropriate and recommendable method for the small-scale assessment and prioritizing of project proposals. If the assessments are well documented, the RIAM can be a method for easy assessing and comparison of the various kinds of projects. In the studied project proposals there were no big surprises in the results: the best ranks were received by the projects, which were assumed to return watersheds toward their original state.
NASA Astrophysics Data System (ADS)
Boisson, F.; Bekaert, V.; Brasse, D.
2016-03-01
Nowadays, Single Photon imaging has become an essential part of molecular imaging and nuclear medicine. Whether to establish a diagnosis or in the therapeutic monitoring, this modality presents performance that continues to improve. For over 50 years, several collimators have been proposed. Mainly governed by collimation parameters, the resolution-sensitivity trade-off is the factor determining the collimator the most suitable for an intended study. One alternative to the common approaches is the rotating slat collimator (RSC). In the present study, we are aiming at developing a preclinical system equipped with a RSC dedicated to mice and rats imaging, which requires both high sensitivity and spatial resolution. We investigated the resolution-sensitivity trade-offs obtained by varying different collimation parameters: (i) the slats height (H), and (ii) the gap between two consecutive slats (g), considering different intrinsic spatial resolutions. One system matrix was generated for each set of collimation parameters (H,g). Spatial resolutions, Signal-to-Noise Ratio (SNR) and sensitivity obtained for all the set of collimation parameters (H,g) were measured in the 2D projections reconstructed with ML-EM. According to our results, 20 mm high slats and a 1 mm gap were chosen as a good RSC candidate for a preclinical detection module. This collimator will ensure a sensitivity greater than 0.2% and a system spatial resolution below 1 mm, considering an intrinsic spatial resolution below 0.8 mm.
NASA Astrophysics Data System (ADS)
Gou, Li-Dan; Xue, Kang; Wang, Gang-Cheng
2011-02-01
We present a 9 × 9 S-matrix and E-matrix. A representation of specialized Birman—Wenzl—Murakami algebra is obtained. Starting from the given braid group representation S-matrix, we obtain the trigonometric solution of Yang-Baxter equation. A unitary matrix Ř(x, ϕ1,ϕ2) is generated via the Yang—Baxterization approach. Then we construct a Yang—Baxter Hamiltonian through the unitary matrix Ř(x, ϕ1,ϕ2). Berry phase of this Yang—Baxter system is investigated in detail.
NASA Astrophysics Data System (ADS)
Souza, Luiz C. G.; Bigot, P.
2016-10-01
One of the most well-known techniques of optimal control is the theory of Linear Quadratic Regulator (LQR). This method was originally applied only to linear systems but has been generalized for non-linear systems: the State Dependent Riccati Equation (SDRE) technique. One of the advantages of SDRE is that the weight matrix selection is the same as in LQR. The difference is that weights are not necessarily constant: they can be state dependent. Then, it gives an additional flexibility to design the control law. Many are applications of SDRE for simulation or real time control but generally SDRE weights are chosen constant so no advantage of this flexibility is taken. This work serves to show through simulation that state dependent weights matrix can improve SDRE control performance. The system is a non-linear flexible rotatory beam. In a brief first part SDRE theory will be explained and the non-linear model detailed. Then, influence of SDRE weight matrix associated with the state Q will be analyzed to get some insight in order to assume a state dependent law. Finally, these laws are tested and compared to constant weight matrix Q. Based on simulation results; one concludes showing the benefits of using an adaptive weight Q rather than a constant one.
Chandel, Shubham; Soni, Jalpa; Ray, Subir kumar; Das, Anwesh; Ghosh, Anirudha; Raj, Satyabrata; Ghosh, Nirmalya
2016-01-01
Information on the polarization properties of scattered light from plasmonic systems are of paramount importance due to fundamental interest and potential applications. However, such studies are severely compromised due to the experimental difficulties in recording full polarization response of plasmonic nanostructures. Here, we report on a novel Mueller matrix spectroscopic system capable of acquiring complete polarization information from single isolated plasmonic nanoparticle/nanostructure. The outstanding issues pertaining to reliable measurements of full 4 × 4 spectroscopic scattering Mueller matrices from single nanoparticle/nanostructures are overcome by integrating an efficient Mueller matrix measurement scheme and a robust eigenvalue calibration method with a dark-field microscopic spectroscopy arrangement. Feasibility of quantitative Mueller matrix polarimetry and its potential utility is illustrated on a simple plasmonic system, that of gold nanorods. The demonstrated ability to record full polarization information over a broad wavelength range and to quantify the intrinsic plasmon polarimetry characteristics via Mueller matrix inverse analysis should lead to a novel route towards quantitative understanding, analysis/interpretation of a number of intricate plasmonic effects and may also prove useful towards development of polarization-controlled novel sensing schemes. PMID:27212687
NASA Astrophysics Data System (ADS)
Guan, Xiaoning; Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Tian, Qinghua; Zhang, Qi; Tian, Feng; Li, Dengao; Zhao, Jumin; Wang, Renfan
2016-10-01
A novel training sequence is designed for the space division multiplexed fiber-optic transmission system in this paper. The training block is consisting of segmented sequence, which can be used to compensate time offset and distortion (such as dispersion) in the transmission link. The channel function can be obtained by one tap equalization in the receiver side. This paper designs the training sequence by adjusting the length of the training signals and implementing matrix transformation, to obtain the coefficient of equalizer for channel detect and equalization. This new training sequence reduces system complexity and improves transmission efficiency at the same time. Compared with blind equalization, the matrix transformation based training sequence can reduce system complexity, and perform targeted equalization to the mechanism of mode coupling in the space division optical fiber system. As a result, it can effectively improve signal transmission quality and reduce bit error rate.
NASA Astrophysics Data System (ADS)
Kun, David William
Unmanned aircraft systems (UASs) are gaining popularity in civil and commercial applications as their lightweight on-board computers become more powerful and affordable, their power storage devices improve, and the Federal Aviation Administration addresses the legal and safety concerns of integrating UASs in the national airspace. Consequently, many researchers are pursuing novel methods to control UASs in order to improve their capabilities, dependability, and safety assurance. The nonlinear control approach is a common choice as it offers several benefits for these highly nonlinear aerospace systems (e.g., the quadrotor). First, the controller design is physically intuitive and is derived from well known dynamic equations. Second, the final control law is valid in a larger region of operation, including far from the equilibrium states. And third, the procedure is largely methodical, requiring less expertise with gain tuning, which can be arduous for a novice engineer. Considering these facts, this thesis proposes a nonlinear controller design method that combines the advantages of adaptive robust control (ARC) with the powerful design tools of linear matrix inequalities (LMI). The ARC-LMI controller is designed with a discontinuous projection-based adaptation law, and guarantees a prescribed transient and steady state tracking performance for uncertain systems in the presence of matched disturbances. The norm of the tracking error is bounded by a known function that depends on the controller design parameters in a known form. Furthermore, the LMI-based part of the controller ensures the stability of the system while overcoming polytopic uncertainties, and minimizes the control effort. This can reduce the number of parameters that require adaptation, and helps to avoid control input saturation. These desirable characteristics make the ARC-LMI control algorithm well suited for the quadrotor UAS, which may have unknown parameters and may encounter external
Zhao, Lin; Guan, Dongxue; Landry, René Jr.; Cheng, Jianhua; Sydorenko, Kostyantyn
2015-01-01
Target positioning systems based on MEMS gyros and laser rangefinders (LRs) have extensive prospects due to their advantages of low cost, small size and easy realization. The target positioning accuracy is mainly determined by the LR’s attitude derived by the gyros. However, the attitude error is large due to the inherent noises from isolated MEMS gyros. In this paper, both accelerometer/magnetometer and LR attitude aiding systems are introduced to aid MEMS gyros. A no-reset Federated Kalman Filter (FKF) is employed, which consists of two local Kalman Filters (KF) and a Master Filter (MF). The local KFs are designed by using the Direction Cosine Matrix (DCM)-based dynamic equations and the measurements from the two aiding systems. The KFs can estimate the attitude simultaneously to limit the attitude errors resulting from the gyros. Then, the MF fuses the redundant attitude estimates to yield globally optimal estimates. Simulation and experimental results demonstrate that the FKF-based system can improve the target positioning accuracy effectively and allow for good fault-tolerant capability. PMID:26512672
38 CFR 4.46 - Accurate measurement.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...
38 CFR 4.46 - Accurate measurement.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...
38 CFR 4.46 - Accurate measurement.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...
38 CFR 4.46 - Accurate measurement.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...
38 CFR 4.46 - Accurate measurement.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...
NASA Astrophysics Data System (ADS)
Gliese, U.; Avanov, L. A.; Barrie, A.; Kujawski, J. T.; Mariano, A. J.; Tucker, C. J.; Chornay, D. J.; Cao, N. T.; Zeuch, M.; Pollock, C. J.; Jacques, A. D.
2013-12-01
The Fast Plasma Investigation (FPI) of the NASA Magnetospheric MultiScale (MMS) mission employs 16 Dual Electron Spectrometers (DESs) and 16 Dual Ion Spectrometers (DISs) with 4 of each type on each of 4 spacecraft to enable fast (30ms for electrons; 150ms for ions) and spatially differentiated measurements of full the 3D particle velocity distributions. This approach presents a new and challenging aspect to the calibration and operation of these instruments on ground and in flight. The response uniformity and reliability of their calibration and the approach to handling any temporal evolution of these calibrated characteristics all assume enhanced importance in this application, where we attempt to understand the meaning of particle distributions within the ion and electron diffusion regions. Traditionally, the micro-channel plate (MCP) based detection systems for electrostatic particle spectrometers have been calibrated by setting a fixed detection threshold and, subsequently, measuring a detection system count rate plateau curve to determine the MCP voltage that ensures the count rate has reached a constant value independent of further variation in the MCP voltage. This is achieved when most of the MCP pulse height distribution (PHD) is located at higher values (larger pulses) than the detection amplifier threshold. This method is adequate in single-channel detection systems and in multi-channel detection systems with very low crosstalk between channels. However, in dense multi-channel systems, it can be inadequate. Furthermore, it fails to fully and individually characterize each of the fundamental parameters of the detection system. We present a new detection system calibration method that enables accurate and repeatable measurement and calibration of MCP gain, MCP efficiency, signal loss due to variation in gain and efficiency, crosstalk from effects both above and below the MCP, noise margin, and stability margin in one single measurement. The fundamental
Bibby, H.M.; Glover, R.B.; Whiteford, P.C.
1995-01-01
Geothermal waters from the Waimangu, Waiotapu-Waikite and Reporoa geothermal systems find their way into three separate watersheds. The heat flow data from each of these drainage areas have been assessed making it possible to compare the heat outputs from two independent methods: direct heat measurements and the chloride flux method. For both the Waiotapu/Reporoa Valley drainage and the Waikite drainage a discrepancy exists between the two assessments, with the heat output observed at the surface (Waiotapu-540 {+-} 110 MW; Waikite-80 MW) nearly double of that calculated from the chloride flux (300 MW; 36 MW respectively). It appears that much of the throughput of chloride does not reach the surface within the area which was monitored and the basic assumption on which the method is based has been violated. For Waimangu the direct heat output is assessed as 510 {+-} 60 MW. However the ratio of enthalpy to chloride concentration of the source fluid is not well determined. Depending on the ratio chosen the heat output could lie between 360 and 800 MW. Although the chloride flux is accurately known, the heat output cannot be measured accurately without well determined data on the source fluid at depth.
R-matrix Analysis of Reactions in the {sup 9}B Compound System
Paris, M. Hale, G.; Hayes-Sterbenz, A.; Jungman, G.
2014-06-15
Recent activity in solving the ‘lithium problem’ in big bang nucleosynthesis has focused on the role that putative resonances may play in resonance-enhanced destruction of {sup 7}Li. Particular attention has been paid to the reactions involving the {sup 9}B compound nuclear system, d+{sup 7}Be→{sup 9}B. These reactions are analyzed via the multichannel, two-body unitary R-matrix method using the code EDA developed by Hale and collaborators. We employ much of the known elastic and reaction data, in a four-channel treatment. The data include elastic {sup 3}He+{sup 6}Li differential cross sections from 0.7 to 2.0 MeV, integrated reaction cross sections for energies from 0.7 to 5.0 MeV for {sup 6}Li({sup 3}He,p){sup 8}Be{sup *} and from 0.4 to 5.0 MeV for the {sup 6}Li({sup 3}He,d){sup 7}Be reaction. Capture data have been added to an earlier analysis with integrated cross section measurements from 0.7 to 0.825 MeV for {sup 6}Li({sup 3}He,γ){sup 9}B. The resulting resonance parameters are compared with tabulated values, and previously unidentified resonances are noted. Our results show that there are no near d+{sup 7}Be threshold resonances with widths that are 10's of keV and reduce the likelihood that a resonance-enhanced mass-7 destruction mechanism, as suggested in recently published work, can explain the {sup 7}Li problem.
Rocha, Mariana Ferreira; Passamani, Marcelo; Louzada, Júlio
2011-01-01
The objective of our work was to verify the value of the vegetation corridor in the conservation of small mammals in fragmented tropical landscapes, using a model system in the southeastern Minas Gerais. We evaluated and compared the composition and structure of small mammals in a vegetation corridor, forest fragments and a coffee matrix. A total of 15 species were recorded, and the highest species richness was observed in the vegetation corridor (13 species), followed by the forest fragments (10) and the coffee matrix (6). The absolute abundance was similar between the vegetation corridor and fragments (F = 22.94; p = 0.064), and the greatest differences occurred between the vegetation corridor and the matrix (F = 22.94; p = 0.001) and the forest fragments and the matrix (F = 22.94; p = 0.007). Six species showed significant habitat preference possibly related to the sensitivity of the species to the forest disturbance. Marmosops incanus was the species most sensitive to disturbance; Akodon montensis, Cerradomys subflavus, Gracilinanus microtarsus and Rhipidomys sp. displayed little sensitivity to disturbance, with a high relative abundance in the vegetation corridor. Calomys sp. was the species least affected by habitat disturbance, displaying a high relative abundance in the coffee matrix. Although the vegetation corridors are narrow (4 m width), our results support the hypothesis in which they work as a forest extension, share most species with the forest fragment and support species richness and abundance closer to forest fragments than to the coffee matrix. Our work highlights the importance and cost-effectiveness of these corridors to biodiversity management in the fragmented Atlantic Forest landscapes and at the regional level. PMID:21912591
Rocha, Mariana Ferreira; Passamani, Marcelo; Louzada, Júlio
2011-01-01
The objective of our work was to verify the value of the vegetation corridor in the conservation of small mammals in fragmented tropical landscapes, using a model system in the southeastern Minas Gerais. We evaluated and compared the composition and structure of small mammals in a vegetation corridor, forest fragments and a coffee matrix. A total of 15 species were recorded, and the highest species richness was observed in the vegetation corridor (13 species), followed by the forest fragments (10) and the coffee matrix (6). The absolute abundance was similar between the vegetation corridor and fragments (F = 22.94; p = 0.064), and the greatest differences occurred between the vegetation corridor and the matrix (F = 22.94; p = 0.001) and the forest fragments and the matrix (F = 22.94; p = 0.007). Six species showed significant habitat preference possibly related to the sensitivity of the species to the forest disturbance. Marmosops incanus was the species most sensitive to disturbance; Akodon montensis, Cerradomys subflavus, Gracilinanus microtarsus and Rhipidomys sp. displayed little sensitivity to disturbance, with a high relative abundance in the vegetation corridor. Calomys sp. was the species least affected by habitat disturbance, displaying a high relative abundance in the coffee matrix. Although the vegetation corridors are narrow (4 m width), our results support the hypothesis in which they work as a forest extension, share most species with the forest fragment and support species richness and abundance closer to forest fragments than to the coffee matrix. Our work highlights the importance and cost-effectiveness of these corridors to biodiversity management in the fragmented Atlantic Forest landscapes and at the regional level.
NASA Astrophysics Data System (ADS)
Motuku, Molefi
The low velocity impact response and damage evolution in unreinforced polymer matrices, conventional polymer matrix composites, and self-repairing polymer matrix composites was investigated. The impact response study of unreinforced matrices and conventional laminates was undertaken because the failure initiation energies, threshold energy levels, failure characteristics and damage evolution in both the matrix material (unreinforced resin plaques) and the composite are intrinsic to proper design of a self-repairing composite. The self-repairing concept was investigated due to its attractive potential to alleviate damage problems in polymer matrix composites. Self-repairing composites, which fall under the category of passive smart polymer composites, have the potential to self repair both micro- and macro-damage resulting from impacts as well as non-impact loading. The self-repairing mechanism is achieved through the incorporation of hollow fibers in addition to the normal solid reinforcing fibers. The hollow fibers store the damage-repairing solution or chemicals that are released into the matrix or damaged zone upon fiber failure to repair and/or arrest damage progression. The room temperature low velocity impact response and damage evolution in DERAKANE 411-350 and 411-C50 vinyl ester unreinforced resin systems was investigated as a function of impact energy level, sample thickness, matrix material and catalyst system. The low velocity impact response of conventional and self-repairing glass reinforced polymer composites was investigated by addressing the fabrication and some of the parameters that influence their response to low velocity impact loading. Specific issues addressed by this study include developing a process to fabricate self-repairing laminates, processing quality; selection of storage material for the repairing solution; release and transportation of repairing solution; the effect of the number, type and spatial distribution of the repairing
NASA Astrophysics Data System (ADS)
Yankovskaya, A.; Cherepanov, D.; Selivanikova, O.
2016-08-01
An extended matrix model of data and knowledge representation on the investigated area, as well as a matrix model of data representation on the territory under investigation, are proposed for the intelligent system of road-climatic zoning of territories (RCZT) - the main information technology of RCZT. A part of the West Siberian region has been selected as the investigated territory. The extended matrix model of knowledge representation is filled out by knowledge engineers with participation of highly qualified experts in the field of RCZT. The matrix model of data representation on the territory under investigation is filled out by persons concerned in RCZT of the motor-roads management system.
Gill, Hasreet K; Cohen, Jennifer D; Ayala-Figueroa, Jesus; Forman-Rubinsky, Rachel; Poggioli, Corey; Bickard, Kevin; Parry, Jean M; Pu, Pu; Hall, David H; Sundaram, Meera V
2016-08-01
Most epithelial cells secrete a glycoprotein-rich apical extracellular matrix that can have diverse but still poorly understood roles in development and physiology. Zona Pellucida (ZP) domain glycoproteins are common constituents of these matrices, and their loss in humans is associated with a number of diseases. Understanding of the functions, organization and regulation of apical matrices has been hampered by difficulties in imaging them both in vivo and ex vivo. We identified the PAN-Apple, mucin and ZP domain glycoprotein LET-653 as an early and transient apical matrix component that shapes developing epithelia in C. elegans. LET-653 has modest effects on shaping of the vulva and epidermis, but is essential to prevent lumen fragmentation in the very narrow, unicellular excretory duct tube. We were able to image the transient LET-653 matrix by both live confocal imaging and transmission electron microscopy. Structure/function and fluorescence recovery after photobleaching studies revealed that LET-653 exists in two separate luminal matrix pools, a loose fibrillar matrix in the central core of the lumen, to which it binds dynamically via its PAN domains, and an apical-membrane-associated matrix, to which it binds stably via its ZP domain. The PAN domains are both necessary and sufficient to confer a cyclic pattern of duct lumen localization that precedes each molt, while the ZP domain is required for lumen integrity. Ectopic expression of full-length LET-653, but not the PAN domains alone, could expand lumen diameter in the developing gut tube, where LET-653 is not normally expressed. Together, these data support a model in which the PAN domains regulate the ability of the LET-653 ZP domain to interact with other factors at the apical membrane, and this ZP domain interaction promotes expansion and maintenance of lumen diameter. These data identify a transient apical matrix component present prior to cuticle secretion in C. elegans, demonstrate critical roles for
Ayala-Figueroa, Jesus; Parry, Jean M.; Pu, Pu; Hall, David H.
2016-01-01
Most epithelial cells secrete a glycoprotein-rich apical extracellular matrix that can have diverse but still poorly understood roles in development and physiology. Zona Pellucida (ZP) domain glycoproteins are common constituents of these matrices, and their loss in humans is associated with a number of diseases. Understanding of the functions, organization and regulation of apical matrices has been hampered by difficulties in imaging them both in vivo and ex vivo. We identified the PAN-Apple, mucin and ZP domain glycoprotein LET-653 as an early and transient apical matrix component that shapes developing epithelia in C. elegans. LET-653 has modest effects on shaping of the vulva and epidermis, but is essential to prevent lumen fragmentation in the very narrow, unicellular excretory duct tube. We were able to image the transient LET-653 matrix by both live confocal imaging and transmission electron microscopy. Structure/function and fluorescence recovery after photobleaching studies revealed that LET-653 exists in two separate luminal matrix pools, a loose fibrillar matrix in the central core of the lumen, to which it binds dynamically via its PAN domains, and an apical-membrane-associated matrix, to which it binds stably via its ZP domain. The PAN domains are both necessary and sufficient to confer a cyclic pattern of duct lumen localization that precedes each molt, while the ZP domain is required for lumen integrity. Ectopic expression of full-length LET-653, but not the PAN domains alone, could expand lumen diameter in the developing gut tube, where LET-653 is not normally expressed. Together, these data support a model in which the PAN domains regulate the ability of the LET-653 ZP domain to interact with other factors at the apical membrane, and this ZP domain interaction promotes expansion and maintenance of lumen diameter. These data identify a transient apical matrix component present prior to cuticle secretion in C. elegans, demonstrate critical roles for
Mücke, Martin; Cuhls, Henning; Radbruch, Lukas; Weigl, Tobias; Rolke, Roman
2014-01-01
Long term depression (LTD) is a neuronal learning mechanism after low frequency stimulation (LFS). This study compares two types of electrodes (concentric vs. matrix) and stimulation frequencies (4 and 30 Hz) to examine homo- and heterosynaptic effects indirectly depicted from the somatosensory profile of healthy subjects. Both electrodes were compared in a prospective, randomized, controlled cross-over study using 4 Hz as the conditioning LFS compared to 30 Hz (intended sham condition). Quantitative sensory testing (QST) was used to examine 13 thermal and mechanical detection and pain thresholds. Sixteen healthy volunteers (10 women, age 31.0±12.7 years) were examined. Depending on the electrodes and frequencies used a divergent pattern of sensory minus signs occurred. Using LFS the concentric electrode increased thermal thresholds, while the matrix electrode rather increased mechanical including deep pain thresholds. Findings after cutaneous neuromodulation using LFS and a matrix electrode are consistent with the concept of heterosynaptic LTD in the human nociceptive system, where deep pain sensitivity was reduced after superficial stimulation of intraepidermal nerve fibres. Cutaneous neuromodulation using LFS and a matrix electrode may be a useful tool to influence deep pain sensitivity in a variety of chronic pain syndromes. PMID:25229556
NASA Technical Reports Server (NTRS)
Seidel, R. C.
1974-01-01
FORTRAN computer subroutines stemming from requirements to process state variable system equations for systems of high order are presented. They find the characteristic equation of a matrix using the method of Danilevsky, the number of roots with positive real parts using the Routh-Horwitz alternate formulation, convert a state variable system description to a Laplace transfer function using the method of Bollinger, and evaluate that transfer function and obtain its frequency response. A sample problem is presented to demonstrate use of the subroutines.
Volatile fractionation in the early solar system and chondrule/matrix complementarity
Bland, Philip A.; Alard, Olivier; Benedix, Gretchen K.; Kearsley, Anton T.; Menzies, Olwyn N.; Watt, Lauren E.; Rogers, Nick W.
2005-01-01
Bulk chondritic meteorites and terrestrial planets show a monotonic depletion in moderately volatile and volatile elements relative to the Sun's photosphere and CI carbonaceous chondrites. Although volatile depletion was the most fundamental chemical process affecting the inner solar nebula, debate continues as to its cause. Carbonaceous chondrites are the most primitive rocks available to us, and fine-grained, volatile-rich matrix is the most primitive component in these rocks. Several volatile depletion models posit a pristine matrix, with uniform CI-like chemistry across the different chondrite groups. To understand the nature of volatile fractionation, we studied minor and trace element abundances in fine-grained matrices of a variety of carbonaceous chondrites. We find that matrix trace element abundances are characteristic for a given chondrite group; they are depleted relative to CI chondrites, but are enriched relative to bulk compositions of their parent meteorites, particularly in volatile siderophile and chalcophile elements. This enrichment produces a highly nonmonotonic trace element pattern that requires a complementary depletion in chondrule compositions to achieve a monotonic bulk. We infer that carbonaceous chondrite matrices are not pristine: they formed from a material reservoir that was already depleted in volatile and moderately volatile elements. Additional thermal processing occurred during chondrule formation, with exchange of volatile siderophile and chalcophile elements between chondrules and matrix. This chemical complementarity shows that these chondritic components formed in the same nebula region. PMID:16174733
Impact of an autologous oxygenating matrix culture system on rat islet transplantation outcome.
Schaschkow, A; Mura, C; Bietiger, W; Peronet, C; Langlois, A; Bodin, F; Dissaux, C; Bruant-Rodier, C; Pinget, M; Jeandidier, N; Juszczak, M T; Sigrist, S; Maillard, E
2015-06-01
Disruption of the pancreatic islet environment combined with the decrease in oxygen supply that occurs during isolation leads to poor islet survival. The aim of this study was to validate the benefit of using a plasma-based scaffold supplemented with perfluorodecalin to improve islet transplantation outcome. Rat islets were cultured in three conditions: i) control group, ii) plasma based-matrix (P-matrix), and iii) P-matrix supplemented with emulsified perfluorodecalin. After 24 h culture, matrix/cell contacts (Integrinβ1, p-FAK/FAK, p-Akt/Akt), survival (caspase 3, TUNEL, FDA/PI), function, and HIF-1α translocation were assessed. Afterwards, P-matrices were dissolved and the islets were intraportally transplanted. Graft function was monitored for 31 days with glycaemia and C-peptide follow up. Inflammation was assessed by histology (macrophage and granulocyte staining) and thrombin/anti-thrombin complex measurement. Islet survival correlated with an increase in integrin, FAK, and Akt activation in P-matrices and function was maintained. Perfluorodecalin supplementation decreased translocation of HIF-1α in the nucleus and post-transplantation islet structure was better preserved in P-matrices, but a quicker activation of IBMIR resulted in early loss of graft function. "Oxygenating" P-matrices provided a real benefit to islet survival and resistance in vivo. However, intraportal transplantation is not suitable for this kind of culture due to IBMIR; thus, alternative sites must be explored.
NASA Astrophysics Data System (ADS)
Modak, Viraj P.; Wyslouzil, Barbara E.; Singer, Sherwin J.
2016-08-01
The crystal-vapor surface free energy γ is an important physical parameter governing physical processes, such as wetting and adhesion. We explore exact and approximate routes to calculate γ based on cleaving an intact crystal into non-interacting sub-systems with crystal-vapor interfaces. We do this by turning off the interactions, ΔV, between the sub-systems. Using the soft-core scheme for turning off ΔV, we find that the free energy varies smoothly with the coupling parameter λ, and a single thermodynamic integration yields the exact γ. We generate another exact method, and a cumulant expansion for γ by expressing the surface free energy in terms of an average of e-βΔV in the intact crystal. The second cumulant, or Gaussian approximation for γ is surprisingly accurate in most situations, even though we find that the underlying probability distribution for ΔV is clearly not Gaussian. We account for this fact by developing a non-Gaussian theory for γ and find that the difference between the non-Gaussian and Gaussian expressions for γ consist of terms that are negligible in many situations. Exact and approximate methods are applied to the (111) surface of a Lennard-Jones crystal and are also tested for more complex molecular solids, the surface of octane and nonadecane. Alkane surfaces were chosen for study because their crystal-vapor surface free energy has been of particular interest for understanding surface freezing in these systems.
Modak, Viraj P; Wyslouzil, Barbara E; Singer, Sherwin J
2016-08-07
The crystal-vapor surface free energy γ is an important physical parameter governing physical processes, such as wetting and adhesion. We explore exact and approximate routes to calculate γ based on cleaving an intact crystal into non-interacting sub-systems with crystal-vapor interfaces. We do this by turning off the interactions, ΔV, between the sub-systems. Using the soft-core scheme for turning off ΔV, we find that the free energy varies smoothly with the coupling parameter λ, and a single thermodynamic integration yields the exact γ. We generate another exact method, and a cumulant expansion for γ by expressing the surface free energy in terms of an average of e(-βΔV) in the intact crystal. The second cumulant, or Gaussian approximation for γ is surprisingly accurate in most situations, even though we find that the underlying probability distribution for ΔV is clearly not Gaussian. We account for this fact by developing a non-Gaussian theory for γ and find that the difference between the non-Gaussian and Gaussian expressions for γ consist of terms that are negligible in many situations. Exact and approximate methods are applied to the (111) surface of a Lennard-Jones crystal and are also tested for more complex molecular solids, the surface of octane and nonadecane. Alkane surfaces were chosen for study because their crystal-vapor surface free energy has been of particular interest for understanding surface freezing in these systems.
NASA Astrophysics Data System (ADS)
Xiao, Weiwei; Li, Li; Lei, Sheng
2017-02-01
Frequency response and their sensitivities analysis are of fundamental importance. Due to the fact that the mode truncation errors of frequency response functions (FRFs) are introduced for two times, the errors of frequency response sensitivities may be larger than other dynamic analysis. Many modal correction approaches (such as modal acceleration methods, dynamic correction methods, force derivation methods and accurate modal superposition methods) have been presented to eliminate the modal-truncation error. However, these approaches are just suitable to the case of un-damped or classically damped systems. The state-space equation based approaches can extend these approaches to non-classically damped systems, but it may be not only computationally expensive, but also lack physical insight provided by the superposition of the complex modes of the equation of motion with original space. This paper is aimed at dealing with the lower-higher-modal truncation problem of harmonic frequency response sensitivity of non-classically damped systems. Based on the Neumann expansion and the frequency shifting technique, the contribution of the truncated lower and higher modes to the harmonic frequency response sensitivity is explicitly expressed only by the available middle modes and system matrices. An extended hybrid expansion method (EHEM) is then proposed by expressing harmonic frequency response sensitivity as the explicit expression of the middle modes and system matrices. The EHEM maintains original-space without having to involve the state-space equation of motion such that it is efficient in computational effort and storage capacity. Finally, a rail specimen is used to illustrate the effectiveness of the proposed method.
NASA Technical Reports Server (NTRS)
Sandford, Stephen P.
2010-01-01
The Climate Absolute Radiance and Refractivity Observatory (CLARREO) is one of four Tier 1 missions recommended by the recent NRC Decadal Survey report on Earth Science and Applications from Space (NRC, 2007). The CLARREO mission addresses the need to provide accurate, broadly acknowledged climate records that are used to enable validated long-term climate projections that become the foundation for informed decisions on mitigation and adaptation policies that address the effects of climate change on society. The CLARREO mission accomplishes this critical objective through rigorous SI traceable decadal change observations that are sensitive to many of the key uncertainties in climate radiative forcings, responses, and feedbacks that in turn drive uncertainty in current climate model projections. These same uncertainties also lead to uncertainty in attribution of climate change to anthropogenic forcing. For the first time CLARREO will make highly accurate, global, SI-traceable decadal change observations sensitive to the most critical, but least understood, climate forcings, responses, and feedbacks. The CLARREO breakthrough is to achieve the required levels of accuracy and traceability to SI standards for a set of observations sensitive to a wide range of key decadal change variables. The required accuracy levels are determined so that climate trend signals can be detected against a background of naturally occurring variability. Climate system natural variability therefore determines what level of accuracy is overkill, and what level is critical to obtain. In this sense, the CLARREO mission requirements are considered optimal from a science value perspective. The accuracy for decadal change traceability to SI standards includes uncertainties associated with instrument calibration, satellite orbit sampling, and analysis methods. Unlike most space missions, the CLARREO requirements are driven not by the instantaneous accuracy of the measurements, but by accuracy in
NASA Astrophysics Data System (ADS)
Lin, Xue-lei; Lu, Xin; Ng, Micheal K.; Sun, Hai-Wei
2016-10-01
A fast accurate approximation method with multigrid solver is proposed to solve a two-dimensional fractional sub-diffusion equation. Using the finite difference discretization of fractional time derivative, a block lower triangular Toeplitz matrix is obtained where each main diagonal block contains a two-dimensional matrix for the Laplacian operator. Our idea is to make use of the block ɛ-circulant approximation via fast Fourier transforms, so that the resulting task is to solve a block diagonal system, where each diagonal block matrix is the sum of a complex scalar times the identity matrix and a Laplacian matrix. We show that the accuracy of the approximation scheme is of O (ɛ). Because of the special diagonal block structure, we employ the multigrid method to solve the resulting linear systems. The convergence of the multigrid method is studied. Numerical examples are presented to illustrate the accuracy of the proposed approximation scheme and the efficiency of the proposed solver.
Poulin, E; Racine, E; Beaulieu, L; Binnekamp, D
2014-06-15
Purpose: In high dose rate brachytherapy (HDR-B), actual catheter reconstruction protocols are slow and errors prompt. The purpose of this study was to evaluate the accuracy and robustness of an electromagnetic (EM) tracking system for improved catheter reconstruction in HDR-B protocols. Methods: For this proof-of-principle, a total of 10 catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a Philips-design 18G biopsy needle (used as an EM stylet) and the second generation Aurora Planar Field Generator from Northern Digital Inc. The Aurora EM system exploits alternating current technology and generates 3D points at 40 Hz. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical CT system with a resolution of 0.089 mm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, 5 catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 seconds or less. This would imply that for a typical clinical implant of 17 catheters, the total reconstruction time would be less than 3 minutes. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.92 ± 0.37 mm and 1.74 ± 1.39 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be significantly more accurate (unpaired t-test, p < 0.05). A mean difference of less than 0.5 mm was found between successive EM reconstructions. Conclusion: The EM reconstruction was found to be faster, more accurate and more robust than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators. We would like to disclose that the equipments, used in this study, is coming from a collaboration with Philips Medical.
Grare, Marion; Prere, Marie-Françoise; Segonds, Christine; Marty, Nicole; Oswald, Eric
2012-01-01
Rapid and cost-effective matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based systems will replace conventional phenotypic methods for routine identification of bacteria. We report here the first evaluation of the new MALDI-TOF MS-based Vitek MS system in a large clinical microbiology laboratory. This system uses an original spectrum classifier algorithm and a specific database designed for the identification of clinically relevant species. We have tested 767 routine clinical isolates representative of 50 genera and 124 species. Vitek MS-based identifications were performed by means of a single deposit on a MALDI disposable target without any prior extraction step and compared with reference identifications obtained mainly with the VITEK2 phenotypic system; if the identifications were discordant, molecular techniques provided reference identifications. The Vitek MS system provided 96.2% correct identifications to the species level (86.7%), to the genus level (8.2%), or within a range of species belonging to different genera (1.3%). Conversely, 1.3% of isolates were misidentified and 2.5% were unidentified, partly because the species was not included in the database; a second deposit provided a successful identification for 0.8% of isolates unidentified with the first deposit. The Vitek MS system is a simple, convenient, and accurate method for routine bacterial identification with a single deposit, considering the high bacterial diversity studied and as evidenced by the low prevalence of species without correct identification. In addition to a second deposit in uncommon cases, expanding the spectral database is expected to further enhance performances. PMID:22593596
Dubois, Damien; Grare, Marion; Prere, Marie-Françoise; Segonds, Christine; Marty, Nicole; Oswald, Eric
2012-08-01
Rapid and cost-effective matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based systems will replace conventional phenotypic methods for routine identification of bacteria. We report here the first evaluation of the new MALDI-TOF MS-based Vitek MS system in a large clinical microbiology laboratory. This system uses an original spectrum classifier algorithm and a specific database designed for the identification of clinically relevant species. We have tested 767 routine clinical isolates representative of 50 genera and 124 species. Vitek MS-based identifications were performed by means of a single deposit on a MALDI disposable target without any prior extraction step and compared with reference identifications obtained mainly with the VITEK2 phenotypic system; if the identifications were discordant, molecular techniques provided reference identifications. The Vitek MS system provided 96.2% correct identifications to the species level (86.7%), to the genus level (8.2%), or within a range of species belonging to different genera (1.3%). Conversely, 1.3% of isolates were misidentified and 2.5% were unidentified, partly because the species was not included in the database; a second deposit provided a successful identification for 0.8% of isolates unidentified with the first deposit. The Vitek MS system is a simple, convenient, and accurate method for routine bacterial identification with a single deposit, considering the high bacterial diversity studied and as evidenced by the low prevalence of species without correct identification. In addition to a second deposit in uncommon cases, expanding the spectral database is expected to further enhance performances.
NASA Astrophysics Data System (ADS)
Duarte-Filho, G. C.; Macedo-Junior, A. F.; Macêdo, A. M. S.
2007-08-01
We introduce a random-matrix description of full counting statistics of charge transfer through a quantum mesoscopic system at finite temperature in the presence two nonideal contacts. Using the exact map between random-matrix theory and the supersymmetric nonlinear σ model, we demonstrate, via explicit calculations, that the saddle-point equation, derived by applying the variational principle to the supersymmetric action, can be cast in the form of the two-terminal version of Nazarov’s circuit theory, thus giving it the status of a controlled approximation. For the case in which the mesoscopic system is a quantum dot at zero temperature, this circuit theory has recently been shown [A. L. R. Barbosa and A. M. S. Macêdo, Phys. Rev. B 71, 235307 (2005)] to reproduce exactly the asymptotic semiclassical limit of the Poisson kernel in perfect agreement with a diagrammatic approach for averaging over the unitary group. We report applications of our formalism to the description of charge transfer through a quantum dot, a quantum chain, and a quantum wire. We also discuss the role of different symmetry classes (orthogonal, unitary, and symplectic) and show how to use known exact connections between the supersymmetric nonlinear σ model and random scattering matrix theories to perform both perturbative and nonperturbative calculations. We believe that our results will help unify the various approaches being currently used in mesoscopic physics of hybrid devices within a single physically sound and mathematically rigorous theoretical scheme.
1985-09-01
SUB. R Flat-Panel Dot-Matrix Displays, Color, Alphanumeric, 23 07 Video, LED, Grey Scale, Luminance, Optical Coupling, 23 11 Contrast, Legibility...based flight simulations and bench test experiments. SPECIFICS Method Utilizing the bottom-up methodology, the electro- optical % characteristics and...switches, with emphasis on the optical effects of fingerprints, and on techniques for optimizing the interpret- ability of rapidly time changing numeric
Tissue matrix arrays for high-throughput screening and systems analysis of cell function.
Beachley, Vince Z; Wolf, Matthew T; Sadtler, Kaitlyn; Manda, Srikanth S; Jacobs, Heather; Blatchley, Michael R; Bader, Joel S; Pandey, Akhilesh; Pardoll, Drew; Elisseeff, Jennifer H
2015-12-01
Cell and protein arrays have demonstrated remarkable utility in the high-throughput evaluation of biological responses; however, they lack the complexity of native tissue and organs. Here we spotted tissue extracellular matrix (ECM) particles as two-dimensional (2D) arrays or incorporated them with cells to generate three-dimensional (3D) cell-matrix microtissue arrays. We then investigated the responses of human stem, cancer and immune cells to tissue ECM arrays originating from 11 different tissues. We validated the 2D and 3D arrays as representative of the in vivo microenvironment by means of quantitative analysis of tissue-specific cellular responses, including matrix production, adhesion and proliferation, and morphological changes after culture. The biological outputs correlated with tissue proteomics, and network analysis identified several proteins linked to cell function. Our methodology enables broad screening of ECMs to connect tissue-specific composition with biological activity, providing a new resource for biomaterials research and further understanding of regeneration and disease mechanisms.
Model system for studies on bone matrix formation by osteogenic cells in microgravity
NASA Astrophysics Data System (ADS)
Quinton, Todd M.; Fattaey, Heideh K.; Motaffaf, Farzaneh; Johnson, Terry C.
1998-01-01
A considerable amount of attention has been focused on the physiological factors that are responsible for the reduction of bone mineralization and mass during prolonged periods in the microgravity environment. Although bone mineralization can be reduced by one percent per month as shown to result from shuttle flights and Mir habitation, the reasons for this phenomenon remain unclear. Changes in specific markers of bone cells upon differentiation indicate that the induction of bone matrix formation is dependent upon these cells reaching confluency. In our laboratory, we have isolated a reversible inhibitor of cellular growth (CeReS-18) that could be important in cell contact inhibition and thus may mimic the signals involved in growth confluency. Preliminary experiments with osteogenic cells have revealed the potential capability of CeReS-18 to inhibit these cells in a reversible manner. We are developing a series of studies, designed at the cellular level, to quantitatively measure the production of bone matrix by osteogenic cells propagated in culture. The use of CeReS-18 would facilitate the study of several factors being assessed regarding matrix formation including the rate of cell population density, hormone induction events, calcium availability, and cell cycle arest. The studies are being conducted in a manner that will allow comparable measurements in the microgravity environment with flight hardware designed and deployed by BioServe Space Technologies.
Accurate Finite Difference Algorithms
NASA Technical Reports Server (NTRS)
Goodrich, John W.
1996-01-01
Two families of finite difference algorithms for computational aeroacoustics are presented and compared. All of the algorithms are single step explicit methods, they have the same order of accuracy in both space and time, with examples up to eleventh order, and they have multidimensional extensions. One of the algorithm families has spectral like high resolution. Propagation with high order and high resolution algorithms can produce accurate results after O(10(exp 6)) periods of propagation with eight grid points per wavelength.
Accurate monotone cubic interpolation
NASA Technical Reports Server (NTRS)
Huynh, Hung T.
1991-01-01
Monotone piecewise cubic interpolants are simple and effective. They are generally third-order accurate, except near strict local extrema where accuracy degenerates to second-order due to the monotonicity constraint. Algorithms for piecewise cubic interpolants, which preserve monotonicity as well as uniform third and fourth-order accuracy are presented. The gain of accuracy is obtained by relaxing the monotonicity constraint in a geometric framework in which the median function plays a crucial role.
NASA Technical Reports Server (NTRS)
Cory, B. J.
1982-01-01
Bandwidth, switching speed, off-state isolation, and reliability over a ten-year mission were factors in determining the optimum available technology for satellite communications switching in 1982. A proof of concept model for a 20 x 20 coupled crossbar switch matrix designed with FET devices for microwave switching and with high speed CMOS LIS for switch crosspoint addressing was fabricated and tested. Results show the design is feasible for application in a multichannel SS-TDMA communications system. Expandibility can readily be achieved with this design. A conceptual design study for a 100 x 100 switch matrix utilizing a coupled crossbar architecture implemented with a monolithic microwave integrated circuits revealed technology needs for high capacity switch matrices.
Sener, Melih K; Schulten, Klaus
2002-03-01
We develop a random matrix model approach to study static disorder in pigment-protein complexes in photosynthetic organisms. As a case study, we examine the ring of B850 bacteriochlorophylls in the peripheral light-harvesting complex of Rhodospirillum molischianum, formulated in terms of an effective Hamiltonian describing the collective electronic excitations of the system. We numerically examine and compare various models of disorder and observe that both the density of states and the absorption spectrum of the model show remarkable spectral universality. For the case of unitary disorder, we develop a method to analytically evaluate the density of states of the ensemble using the supersymmetric formulation of random matrix theory. Succinct formulas that can be readily applied in future studies are provided in an appendix.
Ragan, P M; Chin, V I; Hung, H H; Masuda, K; Thonar, E J; Arner, E C; Grodzinsky, A J; Sandy, J D
2000-11-15
The goal of this study was to examine the effects of mechanical compression on chondrocyte biosynthesis of extracellular matrix (ECM) components during culture in a new alginate disk culture system. Specifically, we have examined chondrocyte biosynthesis rates, and the structure of aggrecan core protein species present in the cell-associated matrix (CM), in the further removed matrix (FRM) and in the surrounding culture medium. In this alginate disk culture system, chondrocytes can be subjected to mechanical deformations similar to those experienced in vivo. Our results show that over an 8-week culture period, chondrocytes synthesize a functional ECM and can respond to mechanical forces similarly to chondrocytes maintained in native cartilage. In the alginate disk system, static compression was shown to decrease and dynamic compression to increase synthesis of aggrecan of bovine chondrocytes. Western blot analysis of the core proteins of aggrecan molecules identified a number of different species that were present in different relative amounts in the CM, FRM, and medium. Over 21 days of culture, the predominant form of aggrecan found in the ECM was a full-length link-stabilized species. In addition, our data show that the application of 40 h of static compression caused an increase in the proportion of newly synthesized aggrecan molecules released into the medium. However, this was not accompanied by a significant change in the size and composition of aggrecan and aggrecan fragments in the different compartments, suggesting that mechanical compression did not alter the catabolic pathways. Together, these data show that chondrocyte function is maintained in an alginate disk culture system and that this culture system is a useful model to examine chondrocyte ECM assembly and some aspects of catabolism normally found in vivo.
Constantinou, Costas; Koutsidis, Georgios
2016-04-15
The formation of acrylamide in model Maillard reaction systems containing phenolic compounds was examined, with regards to phenolic type, concentration, and model system matrix. In dry glyoxal/asparagine waxy maize starch (WMS) systems, 9 out of 10 examined phenolics demonstrated an inhibiting effect, with the most significant reductions (55-60%) observed for caffeoylquinic acids. In WMS glucose/asparagine systems, examination of three different concentrations (0.1, 0.5 and 1 μmol/g WMS) suggested a 'minimum effective concentration' for epicatechin and caffeic acid, whilst addition of caffeoylquinic acids resulted in dose-dependent acrylamide reduction (25-75%). The discordant results of further studies utilising different matrices (dry and wet-to-dry) indicated that, apart from the nature and chemical reactivity, the matrix and the physical state of the reactants might be important for acrylamide formation.
Cammarota, M; Huppes, V; Gaia, S; Degoulet, P
1998-01-01
The development of Health Information Systems is widely determined by the establishment of the underlying information models. An Object-Oriented Matrix Model (OOMM) is described which target is to facilitate the integration of the overall health system. The model is based on information modules named micro-databases that are structured in a three-dimensional network: planning, health structures and information systems. The modelling tool has been developed as a layer on top of a relational database system. A visual browser facilitates the development and maintenance of the information model. The modelling approach has been applied to the Brasilia University Hospital since 1991. The extension of the modelling approach to the Brasilia regional health system is considered.
Klebanoff, S. J.; Kinsella, M. G.; Wight, T. N.
1993-01-01
The degradation of the heparan sulfate proteoglycans of subendothelial matrix by neutrophil elastase and the myeloperoxidase-H2O2-chloride system added separately, sequentially, or together at pH 4.5 to 7.5 was determined by the release of lower molecular weight 35S-labeled material. Elastase alone and the myeloperoxidase system alone caused degradation, and when 4-hour exposure to elastase was followed by 15 minutes of exposure to the myeloperoxidase system, the effect was greater than additive. A greater than additive effect was not observed when elastase followed the myeloperoxidase system or the two were added together. Chloride (or sulfate) alone increased the release of 35S-labeled material from elastase-treated matrix, although the effect of 0.1 M chloride was not as great as that observed when an equivalent concentration of chloride was combined with myeloperoxidase and H2O2. The release of these systems at sites of adherence of neutrophils to glomerular basement membrane may contribute to neutrophil-associated proteinuria. Images Figure 1 Figure 2 Figure 5 Figure 7 PMID:8395774
NASA Astrophysics Data System (ADS)
Eichler, C.; Mlynek, J.; Butscher, J.; Kurpiers, P.; Hammerer, K.; Osborne, T. J.; Wallraff, A.
2015-10-01
Improving the understanding of strongly correlated quantum many-body systems such as gases of interacting atoms or electrons is one of the most important challenges in modern condensed matter physics, materials research, and chemistry. Enormous progress has been made in the past decades in developing both classical and quantum approaches to calculate, simulate, and experimentally probe the properties of such systems. In this work, we use a combination of classical and quantum methods to experimentally explore the properties of an interacting quantum gas by creating experimental realizations of continuous matrix product states—a class of states that has proven extremely powerful as a variational ansatz for numerical simulations. By systematically preparing and probing these states using a circuit quantum electrodynamics system, we experimentally determine a good approximation to the ground-state wave function of the Lieb-Liniger Hamiltonian, which describes an interacting Bose gas in one dimension. Since the simulated Hamiltonian is encoded in the measurement observable rather than the controlled quantum system, this approach has the potential to apply to a variety of models including those involving multicomponent interacting fields. Our findings also hint at the possibility of experimentally exploring general properties of matrix product states and entanglement theory. The scheme presented here is applicable to a broad range of systems exploiting strong and tunable light-matter interactions.
Ceramic Matrix Composites (CMC) Life Prediction Development
NASA Technical Reports Server (NTRS)
Levine, Stanley R.; Verrilli, Michael J.; Thomas, David J.; Halbig, Michael C.; Calomino, Anthony M.; Ellis, John R.; Opila, Elizabeth J.
1990-01-01
Advanced launch systems will very likely incorporate fiber reinforced ceramic matrix composites (CMC) in critical propulsion and airframe components. The use of CMC will save weight, increase operating margin, safety and performance, and improve reuse capability. For reusable and single mission use, accurate life prediction is critical to success. The tools to accomplish this are immature and not oriented toward the behavior of carbon fiber reinforced silicon carbide (C/SiC), the primary system of interest for many applications. This paper describes an approach and progress made to satisfy the need to develop an integrated life prediction system that addresses mechanical durability and environmental degradation.
NASA Astrophysics Data System (ADS)
Ganguli, Anurag; Saha, Bhaskar; Raghavan, Ajay; Kiesel, Peter; Arakaki, Kyle; Schuh, Andreas; Schwartz, Julian; Hegyi, Alex; Sommer, Lars Wilko; Lochbaum, Alexander; Sahu, Saroj; Alamgir, Mohamed
2017-02-01
A key challenge hindering the mass adoption of Lithium-ion and other next-gen chemistries in advanced battery applications such as hybrid/electric vehicles (xEVs) has been management of their functional performance for more effective battery utilization and control over their life. Contemporary battery management systems (BMS) reliant on monitoring external parameters such as voltage and current to ensure safe battery operation with the required performance usually result in overdesign and inefficient use of capacity. More informative embedded sensors are desirable for internal cell state monitoring, which could provide accurate state-of-charge (SOC) and state-of-health (SOH) estimates and early failure indicators. Here we present a promising new embedded sensing option developed by our team for cell monitoring, fiber-optic (FO) sensors. High-performance large-format pouch cells with embedded FO sensors were fabricated. This second part of the paper focuses on the internal signals obtained from these FO sensors. The details of the method to isolate intercalation strain and temperature signals are discussed. Data collected under various xEV operational conditions are presented. An algorithm employing dynamic time warping and Kalman filtering was used to estimate state-of-charge with high accuracy from these internal FO signals. Their utility for high-accuracy, predictive state-of-health estimation is also explored.
NASA Astrophysics Data System (ADS)
Raghavan, Ajay; Kiesel, Peter; Sommer, Lars Wilko; Schwartz, Julian; Lochbaum, Alexander; Hegyi, Alex; Schuh, Andreas; Arakaki, Kyle; Saha, Bhaskar; Ganguli, Anurag; Kim, Kyung Ho; Kim, ChaeAh; Hah, Hoe Jin; Kim, SeokKoo; Hwang, Gyu-Ok; Chung, Geun-Chang; Choi, Bokkyu; Alamgir, Mohamed
2017-02-01
A key challenge hindering the mass adoption of Lithium-ion and other next-gen chemistries in advanced battery applications such as hybrid/electric vehicles (xEVs) has been management of their functional performance for more effective battery utilization and control over their life. Contemporary battery management systems (BMS) reliant on monitoring external parameters such as voltage and current to ensure safe battery operation with the required performance usually result in overdesign and inefficient use of capacity. More informative embedded sensors are desirable for internal cell state monitoring, which could provide accurate state-of-charge (SOC) and state-of-health (SOH) estimates and early failure indicators. Here we present a promising new embedded sensing option developed by our team for cell monitoring, fiber-optic sensors. High-performance large-format pouch cells with embedded fiber-optic sensors were fabricated. The first of this two-part paper focuses on the embedding method details and performance of these cells. The seal integrity, capacity retention, cycle life, compatibility with existing module designs, and mass-volume cost estimates indicate their suitability for xEV and other advanced battery applications. The second part of the paper focuses on the internal strain and temperature signals obtained from these sensors under various conditions and their utility for high-accuracy cell state estimation algorithms.
Planar system for magnetic induction conductivity measurement using a sensor matrix.
Riedel, C H; Keppelen, M; Nani, S; Merges, R D; Dössel, O
2004-02-01
In this study the performance of an axial gradiometer sensor for magnetic induction tomography was investigated and the results of measurements to determine the precision and sensitivity of the sensor were undertaken. In the first part of the study a single gradiometer sensor was used and the noise and drift were measured for two excitation current values at a single frequency of 600 kHz. The variations of the real and imaginary received signal components with conductivity were then obtained for samples with 0-5 S m(-1). Both sets of measurements were repeated using two different forms of capacitive shielding. In the second part of the study the results of preliminary measurements obtained with a 2 x 2 planar matrix of axial gradiometers are given. The results of a simulation of a similar matrix using a commercial electromagnetic field calculation programme are also presented for comparison. For the sample utilized, the sensor output showed a linear variation with conductivity for the imaginary component of 0.033 mV S(-1) m using an excitation current of 316 mA at 600 kHz. No apparent correlation with conductivity for the real component was observed. The noise and drift of the imaginary component of the sensor output were 0.001 mV and 0.006 mV respectively, for the same excitation current. The results of the planar matrix measurements and simulations suggest that significant sensitivity is provided by using the measurement coils of the adjacent sensors. The measurement results however suggest that large improvements in the sensor noise and drift performance are required for these data to be of use.
Wu, Q; Pei, X; Cao, R; Hu, L; Wu, Y
2014-06-01
Purpose: The purpose of this work was to develop a registration framework and method based on the software platform of ARTS-IGRT and implement in C++ based on ITK libraries to register CT images and CBCT images. ARTS-IGRT was a part of our self-developed accurate radiation planning system ARTS. Methods: Mutual information (MI) registration treated each voxel equally. Actually, different voxels even having same intensity should be treated differently in the registration procedure. According to their importance values calculated from self-information, a similarity measure was proposed which combined the spatial importance of a voxel with MI (S-MI). For lung registration, Firstly, a global alignment method was adopted to minimize the margin error and achieve the alignment of these two images on the whole. The result obtained at the low resolution level was then interpolated to become the initial conditions for the higher resolution computation. Secondly, a new similarity measurement S-MI was established to quantify how close the two input image volumes were to each other. Finally, Demons model was applied to compute the deformable map. Results: Registration tools were tested for head-neck and lung images and the average region was 128*128*49. The rigid registration took approximately 2 min and converged 10% faster than traditional MI algorithm, the accuracy reached 1mm for head-neck images. For lung images, the improved symmetric Demons registration process was completed in an average of 5 min using a 2.4GHz dual core CPU. Conclusion: A registration framework was developed to correct patient's setup according to register the planning CT volume data and the daily reconstructed 3D CBCT data. The experiments showed that the spatial MI algorithm can be adopted for head-neck images. The improved Demons deformable registration was more suitable to lung images, and rigid alignment should be applied before deformable registration to get more accurate result. Supported by
Markovich, R J; Taylor, A K; Rosen, J
1997-12-01
The apparent loss of nitroglycerin in a prototype transdermal nitroglycerin system was investigated by attenuated total reflectance infrared (ATR-IR) microspectroscopy and high performance liquid chromatography (HPLC). Several transdermal nitroglycerin lots placed under controlled storage conditions exhibited loss of drug potency (up to 10%) along with the appearance of a defect in the polymer film laminate facestock. A significant loss of nitroglycerin from the transdermal drug/adhesive matrix may reduce the bioavailabilty of nitroglycerin to the patient. ATR-IR analysis confirmed that nitroglycerin migrated from the drug/adhesive matrix to the facestock polyester layer under storage conditions and that nitroglycerin was retained in the facestock polyester layer. An alternate sample extraction solution successfully removed the nitroglycerin from both the adhesive matrix and facestock polyester layer with nearly 100% labeled strength recovered. The relationship between the migration of nitroglycerin into the facestock polyester layer and the appearance of the defect in the facestock aluminum layer is discussed and a nitroglycerin-aluminum metal reaction mechanism is proposed.
NASA Astrophysics Data System (ADS)
Miura, Shinichi; Okazaki, Susumu
2001-09-01
In this paper, the path integral molecular dynamics (PIMD) method has been extended to employ an efficient approximation of the path action referred to as the pair density matrix approximation. Configurations of the isomorphic classical systems were dynamically sampled by introducing fictitious momenta as in the PIMD based on the standard primitive approximation. The indistinguishability of the particles was handled by a pseudopotential of particle permutation that is an extension of our previous one [J. Chem. Phys. 112, 10 116 (2000)]. As a test of our methodology for Boltzmann statistics, calculations have been performed for liquid helium-4 at 4 K. We found that the PIMD with the pair density matrix approximation dramatically reduced the computational cost to obtain the structural as well as dynamical (using the centroid molecular dynamics approximation) properties at the same level of accuracy as that with the primitive approximation. With respect to the identical particles, we performed the calculation of a bosonic triatomic cluster. Unlike the primitive approximation, the pseudopotential scheme based on the pair density matrix approximation described well the bosonic correlation among the interacting atoms. Convergence with a small number of discretization of the path achieved by this approximation enables us to construct a method of avoiding the problem of the vanishing pseudopotential encountered in the calculations by the primitive approximation.
Hsueh, Po-Ren; Kuo, Lu-Cheng; Chang, Tsung-Chain; Lee, Tai-Fen; Teng, Shih-Hua; Chuang, Yu-Chung; Teng, Lee-Jene
2014-01-01
Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) (Bruker Biotyper) was able to accurately identify 98.6% (142/144) of Acinetobacter baumannii isolates, 72.4% (63/87) of A. nosocomialis isolates, and 97.6% (41/42) of A. pittii isolates. All Acinetobacter junii, A. ursingii, A. johnsonii, and A. radioresistens isolates (n = 28) could also be identified correctly by Bruker Biotyper. PMID:24899038
Verslegers, Mieke; Lemmens, Kim; Van Hove, Inge; Moons, Lieve
2013-06-01
It has been 50 years since Gross and Lapiere discovered collagenolytic activity during tadpole tail metamorphosis, which was later on revealed as MMP-1, the founding member of the matrix metalloproteinases (MMPs). Currently, MMPs constitute a large group of endoproteases that are not only able to cleave all protein components of the extracellular matrix, but also to activate or inactivate many other signaling molecules, such as receptors, adhesion molecules and growth factors. Elevated MMP levels are associated with an increasing number of injuries and disorders, such as cancer, inflammation and auto-immune diseases. Yet, MMP upregulation has also been implicated in many physiological functions such as embryonic development, wound healing and angiogenesis and therefore, these proteinases are considered to be crucial mediators in many biological processes. Over the past decennia, MMP research has gained considerable attention in several pathologies, most prominently in the field of cancer metastasis, and more recent investigations also focus on the nervous system, with a striking emphasis on the gelatinases, MMP-2 and MMP-9. Unfortunately, the contribution of these gelatinases to neuropathological disorders, like multiple sclerosis and Alzheimer's disease, has overshadowed their potential as modulators of fundamental nervous system functions. Within this review, we wish to highlight the currently known or suggested actions of MMP-2 and MMP-9 in the developing and adult nervous system and their potential to improve repair or regeneration after nervous system injury.
Hwang, Hee Sung; Shin, Gi Won; Park, Han Jin; Ryu, Chang Y; Jung, Gyoo Yeol
2013-09-02
Capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) analysis is a prominent bioseparation method based on the mobility diversity caused by sequence-induced conformational differences of single-stranded DNA. The use of Pluronic polymer matrix has opened up new opportunities for CE-SSCP, because it improved the resolution for various genetic analyses. However, there still exists a challenge in optimizing Pluronic-based CE-SSCP, because the physical properties of Pluronic solutions are sensitive to temperature, particularly near the gelation temperature, where the viscoelasticity of Pluronic F108 solutions sharply changes from that of a Newtonian fluid to a hydrogel upon heating. We have focused on a set of experiments to control the ambient temperature of the CE system with the aim of enhancing the reliability of the CE-SSCP analysis by using the Applied Biosystems ABI 3130xl genetic analyzer with Pluronic F108 solution matrix. The ambient temperature control allowed us to vary the inlet and outlet portion of the capillary column, while the temperature of the column was kept at 35°C. The resolution to separate 2 single-base-pair-differing DNA fragments was significantly enhanced by changing the temperature from 19 to 30°C. The viscoelastic properties of the F108 solution matrix upon heating were also investigated by ex situ rheological experiments with an effort to reveal how the development of gels in Pluronic solutions affects the resolution of CE-SSCP. We found that the column inlet and outlet temperatures of the capillary column have to be controlled to optimize the resolution in CE-SSCP by using the Pluronic matrix.
Song, Qiang; Liu, Fang; Cao, Jinde; Yu, Wenwu
2013-12-01
This paper considers the leader-following consensus problem for multiagent systems with inherent nonlinear dynamics. Some M-matrix strategies are developed to address several challenging issues in the pinning control of multiagent systems by using algebraic graph theory and the properties of nonnegative matrices. It is shown that second-order leader-following consensus in a nonlinear multiagent system can be reached if the virtual leader has a directed path to every follower and a derived quantity is greater than a positive threshold. In particular, this paper analytically proves that leader-following consensus may be easier to be achieved by pinning more agents or increasing the pinning feedback gains. A selective pinning scheme is then proposed for nonlinear multiagent systems with directed network topologies. Numerical results are given to verify the theoretical analysis.
Luo, Yanping; Siu, Gilman K H; Yeung, Amy S F; Chen, Jonathan H K; Ho, Pak Leung; Leung, K W; Tsang, Jacqueline L Y; Cheng, Vincent C C; Guo, Ling; Yang, Jiyong; Ye, Liyan; Yam, Wing-Cheong
2015-01-01
Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) MS systems was not officially launched for diagnostic use in clinical microbiology laboratories in China until 2012. Here, we report the findings from the first large-scale evaluation study of VITEK MS for routine bacterial identification in two major diagnostic centres in Beijing and Hong Kong. A total of 2266 unique isolates representing 56 genera and 127 species were analysed, and results were compared to those obtained by VITEK 2. Any discrepancies were resolved by 16S rRNA sequencing. Overall, VITEK MS provided correct identification for 2246 (99.1%) isolates, including 2193 (96.8 %) with correct species-level identifications and 53 (2.3 %) matched at the genus level only. VITEK MS surpassed VITEK 2 consistently in species-level identification of important pathogens, including non-Enterobacteriaceae Gram-negative bacilli (94.7 versus 92 %), staphylococci (99.7 versus 92.4 %), streptococci (92.6 versus 79.4 %), enterococci (98.8 versus 92.6 %) and Clostridium spp. (97.3 versus 55.5 %). The findings demonstrated that VITEK MS is highly accurate and reliable for routine bacterial identification in clinical settings in China.
Tang, Fei
2004-01-01
the matrix choice (elemental Al) and the ''low shear'' consolidation methods utilized. This reinforcement effectiveness is further evidenced by elastic modulus measurements of the composites that are very close to the upper bound predictions of the rule of mixtures. The load partitioning measurements by neutron diffraction showed that composite samples made from GARS powders present significantly higher load transfer efficiency than the composites made from commercially atomized powders. Also, the composite samples made from GARS powders show a higher strengthening effect and ductility than the samples made from commercial purity powders. The higher load transfer efficiency and higher strength and ductility may result from an enhanced inter-particle bonding strength, promoted by the ''clean'' interfaces between particles. Further analysis of the load sharing measurements and the calculated values of the mismatch of coefficient of thermal expansion (CTE) and the geometrically necessary dislocation (GND) effects suggest that these strengthening mechanisms can be combined to predict accurately the strength of the composites.
NASA Technical Reports Server (NTRS)
Hinkley, Jeffrey A.; Connell, John W.
2012-01-01
In choosing a polymer-matrix composite material for a particular application, a number of factors need to be weighed. Among these are mechanical requirements, fabrication method (e.g. press-molding, resin infusion, filament winding, tape layup), and use conditions. Primary among the environmental exposures encountered in aerospace structures are moisture and elevated temperatures, but certain applications may require resistance to other fluids and solvents, alkaline agents, thermal cycling, radiation, or rapid, localized heating (for example, lightning strike). In this chapter, the main classes of polymer resin systems found in aerospace composites will be discussed. Within each class, their responses to environmental factors and the associated degradation mechanisms will be reviewed.
NASA Astrophysics Data System (ADS)
Chen, Xin
2014-04-01
Understanding the roles of the temporary and spatial structures of quantum functional noise in open multilevel quantum molecular systems attracts a lot of theoretical interests. I want to establish a rigorous and general framework for functional quantum noises from the constructive and computational perspectives, i.e., how to generate the random trajectories to reproduce the kernel and path ordering of the influence functional with effective Monte Carlo methods for arbitrary spectral densities. This construction approach aims to unify the existing stochastic models to rigorously describe the temporary and spatial structure of Gaussian quantum noises. In this paper, I review the Euclidean imaginary time influence functional and propose the stochastic matrix multiplication scheme to calculate reduced equilibrium density matrices (REDM). In addition, I review and discuss the Feynman-Vernon influence functional according to the Gaussian quadratic integral, particularly its imaginary part which is critical to the rigorous description of the quantum detailed balance. As a result, I establish the conditions under which the influence functional can be interpreted as the average of exponential functional operator over real-valued Gaussian processes for open multilevel quantum systems. I also show the difference between the local and nonlocal phonons within this framework. With the stochastic matrix multiplication scheme, I compare the normalized REDM with the Boltzmann equilibrium distribution for open multilevel quantum systems.
Chen, Xin
2014-04-21
Understanding the roles of the temporary and spatial structures of quantum functional noise in open multilevel quantum molecular systems attracts a lot of theoretical interests. I want to establish a rigorous and general framework for functional quantum noises from the constructive and computational perspectives, i.e., how to generate the random trajectories to reproduce the kernel and path ordering of the influence functional with effective Monte Carlo methods for arbitrary spectral densities. This construction approach aims to unify the existing stochastic models to rigorously describe the temporary and spatial structure of Gaussian quantum noises. In this paper, I review the Euclidean imaginary time influence functional and propose the stochastic matrix multiplication scheme to calculate reduced equilibrium density matrices (REDM). In addition, I review and discuss the Feynman-Vernon influence functional according to the Gaussian quadratic integral, particularly its imaginary part which is critical to the rigorous description of the quantum detailed balance. As a result, I establish the conditions under which the influence functional can be interpreted as the average of exponential functional operator over real-valued Gaussian processes for open multilevel quantum systems. I also show the difference between the local and nonlocal phonons within this framework. With the stochastic matrix multiplication scheme, I compare the normalized REDM with the Boltzmann equilibrium distribution for open multilevel quantum systems.
NASA Astrophysics Data System (ADS)
Bonilla, Jose; Kalwa, Fritz; Händel, Falk; Binder, Martin; Stefan, Catalin
2016-04-01
The Dupuit-Thiem equation is normally used to assess flow towards a pumping well in unconfined aquifers under steady-state conditions. For the formulation of the equation it is assumed that flow is laminar, radial and horizontal towards the well. It is well known that these assumptions are not met in the vicinity of the well; some authors restrict the application of the equation only to a radius larger than 1.5-fold the aquifer thickness. In this study, the equation accuracy to predict the pressure head is evaluated as a simple and quick analytical method to describe the flow pattern for different injection rates in the LSAW. A laboratory scale aquifer-well system (LSAW) was implemented to study the aquifer recharge through wells. The LSAW consists of a 1.0 m-diameter tank with a height of 1.1 meters, filled with sand and a screened well in the center with a diameter of 0.025 m. A regulated outflow system establishes a controlled water level at the tank wall to simulate various aquifer thicknesses. The pressure head at the bottom of the tank along one axis can be measured to assess the flow profile every 0.1 m between the well and the tank wall. In order to evaluate the accuracy of the Dupuit-Thiem equation, a combination of different injection rates and aquifer thicknesses were simulated in the LSAW. Contrary to what was expected (significant differences between the measured and calculated pressure heads in the well), the absolute difference between the calculated and measured pressure head is less than 10%. Beside this, the highest differences are not observed in the well itself, but in the near proximity of it, at a radius of 0.1 m. The results further show that the difference between the calculated and measured pressure heads tends to decrease with higher flow rates. Despite its limitations (assumption of laminar and horizontal flow throughout the whole aquifer), the Dupuit-Thiem equation is considered to accurately represent the flow system in the LSAW.
Accurate quantum chemical calculations
NASA Technical Reports Server (NTRS)
Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.
1989-01-01
An important goal of quantum chemical calculations is to provide an understanding of chemical bonding and molecular electronic structure. A second goal, the prediction of energy differences to chemical accuracy, has been much harder to attain. First, the computational resources required to achieve such accuracy are very large, and second, it is not straightforward to demonstrate that an apparently accurate result, in terms of agreement with experiment, does not result from a cancellation of errors. Recent advances in electronic structure methodology, coupled with the power of vector supercomputers, have made it possible to solve a number of electronic structure problems exactly using the full configuration interaction (FCI) method within a subspace of the complete Hilbert space. These exact results can be used to benchmark approximate techniques that are applicable to a wider range of chemical and physical problems. The methodology of many-electron quantum chemistry is reviewed. Methods are considered in detail for performing FCI calculations. The application of FCI methods to several three-electron problems in molecular physics are discussed. A number of benchmark applications of FCI wave functions are described. Atomic basis sets and the development of improved methods for handling very large basis sets are discussed: these are then applied to a number of chemical and spectroscopic problems; to transition metals; and to problems involving potential energy surfaces. Although the experiences described give considerable grounds for optimism about the general ability to perform accurate calculations, there are several problems that have proved less tractable, at least with current computer resources, and these and possible solutions are discussed.
2017-01-01
Objective To determine whether less invasive endometrial (EM) aspiration biopsy is adequately accurate for evaluating treatment outcomes compared to the dilatation and curettage (D&C) biopsy in early-stage endometrial cancer (EC) patients treated with high dose oral progestin and levonorgestrel intrauterine system (LNG-IUS). Methods We conducted a prospective observational study with patients younger than 40 years who were diagnosed with clinical stage IA, The International Federation of Gynecology and Obstetrics grade 1 or 2 endometrioid adenocarcinoma and sought to maintain their fertility. The patients were treated with medroxyprogesterone acetate 500 mg/day and LNG-IUS. Treatment responses were evaluated every 3 months. EM aspiration biopsy was conducted after LNG-IUS removal followed D&C. The tissue samples were histologically compared. The diagnostic concordance rate of the two tests was examined with κ statistics. Results Twenty-eight pairs of EM samples were obtained from five patients. The diagnostic concordance rate of D&C and EM aspiration biopsy was 39.3% (κ value=0.26). Of the seven samples diagnosed as normal with D&C, three (42.8%) were diagnosed as normal by using EM aspiration biopsy. Of the eight samples diagnosed with endometrioid adenocarcinoma by using D&C, three (37.5%) were diagnosed with endometrioid adenocarcinoma by using EM aspiration biopsy. Of the 13 complex EM hyperplasia samples diagnosed with the D&C, five (38.5%) were diagnosed with EM hyperplasia by using EM aspiration biopsy. Of the samples obtained through EM aspiration, 46.4% were insufficient for histological evaluation. Conclusion To evaluate the treatment responses of patients with early-stage EC treated with high dose oral progestin and LNG-IUS, D&C should be conducted after LNG-IUS removal. PMID:27670255
FRET study in oligopeptide-linked donor-acceptor system in PVA matrix
NASA Astrophysics Data System (ADS)
Shah, Sunil; Mandecki, Wlodek; Li, Ji; Gryczynski, Zygmunt; Borejdo, Julian; Gryczynski, Ignacy; Fudala, Rafal
2016-12-01
An oligopeptide: Lys-Gly-Pro-Arg-Ser-Leu-Ser-Gly-Lys-NH2, cleaved specifically by a matrix metalloproteinase 9 (MMP-9) at the Ser-Leu bond, was labeled on the ɛ-NH2 groups of lysine with donor (5, 6 TAMRA) and acceptor (HiLyte647) dye. The donor control was a peptide labeled with 5, 6 TAMRA only on the C-terminal lysine, and the acceptor control was free HiLyte647. Following three products were studied by dissolving in 10% (w/w) poly(vinyl alcohol) and dried on glass slides forming 200 micron films. Absorption spectra of the films show full additivity of donor and acceptor absorptions. A strong Fluorescence Resonance Energy Transfer (FRET) with an efficiency of about 85% was observed in the fluorescence emission and excitation spectra. The lifetime of the donor was shorter and heterogeneous compared with the donor control.
Quantum propagation and confinement in 1D systems using the transfer-matrix method
NASA Astrophysics Data System (ADS)
Pujol, Olivier; Carles, Robert; Pérez, José-Philippe
2014-05-01
The aim of this article is to provide some Matlab scripts to the teaching community in quantum physics. The scripts are based on the transfer-matrix formalism and offer a very efficient and versatile tool to solve problems of a physical object (electron, proton, neutron, etc) with one-dimensional (1D) stationary potential energy. Resonant tunnelling through a multiple-barrier or confinement in wells of various shapes is particularly analysed. The results are quantitatively discussed with semiconductor heterostructures, harmonic and anharmonic molecular vibrations, or neutrons in a gravity field. Scripts and other examples (hydrogen-like ions and transmission by a smooth variation of potential energy) are available freely at http://www-loa.univ-lille1.fr/˜pujol in three languages: English, French and Spanish.
NASA Astrophysics Data System (ADS)
Peng, Berney; Alonzo, Carlo A. C.; Xia, Lawrence; Speroni, Lucia; Georgakoudi, Irene; Soto, Ana M.; Sonnenschein, Carlos; Cronin-Golomb, Mark
2013-09-01
Biomechanics plays a central role in breast epithelial morphogenesis. In this study we have used 3D cultures in which normal breast epithelial cells are able to organize into rounded acini and tubular ducts, the main structures found in the breast tissue. We have identified fiber organization as a main determinant of ductal organization. While bulk rheological properties of the matrix seem to play a negligible role in determining the proportion of acini versus ducts, local changes may be pivotal in shape determination. As such, the ability to make microscale rheology measurements coupled with simultaneous optical imaging in 3D cultures can be critical to assess the biomechanical factors underlying epithelial morphogenesis. This paper describes the inclusion of optical tweezers based microrheology in a microscope that had been designed for nonlinear optical imaging of collagen networks in ECM. We propose two microrheology methods and show preliminary results using a gelatin hydrogel and collagen/Matrigel 3D cultures containing mammary gland epithelial cells.
Pollard, S J T; Farmer, J G; Knight, D M; Young, P J
2002-01-01
Commercial mono- and polyclonal enzyme-linked immunosorbent assay (ELISA) systems were applied to the on-site analysis of weathered hydrocarbon-contaminated soils at a former integrated steelworks. Comparisons were made between concentrations of solvent extractable matter (SEM) determined gravimetrically by Soxhlet (dichloromethane) extraction and those estimated immunologically by ELISA determination over a concentration range of 2000-330,000 mg SEM/kg soil dry weight. Both ELISA systems tinder-reported for the more weathered soil samples. Results suggest this is due to matrix effects in the sample rather than any inherent bias in the ELISA systems and it is concluded that, for weathered hydrocarbons typical of steelworks and coke production sites, the use of ELISA requires careful consideration as a field technique. Consideration of the target analyte relative to the composition of the hydrocarbon waste encountered appears critical.
NASA Technical Reports Server (NTRS)
Zhu, Dongming; Fox, Dennis S.; Ghosn, Louis J.; Harder, Bryan
2011-01-01
Environmental barrier coatings will play a crucial role in future advanced gas turbine engines because of their ability to significantly extend the temperature capability and stability of SiC/SiC ceramic matrix composite (CMC) engine components, thus improving the engine performance. In order to develop high performance, robust coating systems for engine components, appropriate test approaches simulating operating temperature gradient and stress environments for evaluating the critical coating properties must be established. In this paper, thermal gradient mechanical testing approaches for evaluating creep and fatigue behavior of environmental barrier coated SiC/SiC CMC systems will be described. The creep and fatigue behavior of Hafnia and ytterbium silicate environmental barrier coatings on SiC/SiC CMC systems will be reported in simulated environmental exposure conditions. The coating failure mechanisms will also be discussed under the heat flux and stress conditions.
Aleksovski, Aleksandar; Van Bockstal, Pieter-Jan; Roškar, Robert; Sovány, Tamás; Regdon, Géza; De Beer, Thomas; Vervaet, Chris; Dreu, Rok
2016-06-10
The aim of this study was to develop, evaluate and compare extended release mini-matrices based on metoprolol tartrate (MPT) and either glyceryl behenate (GB) or glyceryl palmitostearate (GPS). Mini-matrices were produced by three different techniques: hot melt extrusion, compression of melt granulates and prilling. Hot-melt extrusion and compression of granules obtained from melted material proved to be reliable, robust and reproducible techniques with aim of obtaining extended release matrices. Prilling tended to be susceptible to increased melt viscosity. Direct compression was not applicable for mini-matrix production due to poor powder flow. In general MPT release from all matrices was affected by its loading and the size of the units/particles. Processing of GB-MPT mixtures by different techniques did not lead to different drug release rates and patterns, while in case of GPS differently obtained matrices provided diverse MPT release outcomes. Matrices based on GB tended to have higher porosity compared to ones composed of GPS and thus most of the GB-based formulations showed faster drug delivery. FT-IR analysis revealed no interactions between primary components used for matrix production and Raman mapping outlined uniform MPT distribution throughout the units. DSC and X-ray studies revealed significant changes in the crystallinity of glycerides after storage under room conditions (GPS samples) and at increased temperature (GB and GPS samples), which was correlated to the changes seen in drug release rate and pattern after storage. Media composition in general tended to insignificantly affect GB matrices, while in case of GPS matrices increasing the pH and presence of biorelevant compounds induced faster drug release.
Richter, Marten Knorr, Andreas
2010-04-15
Time convolution less density matrix theory (TCL) is a powerful and well established tool to investigate strong system-bath coupling for linear optical spectra. We show that TCL equations can be generalised to the nonlinear optical response up to a chosen order in the optical field. This goal is achieved via an time convolution less perturbation scheme for the reduced density matrices of the electronic system. In our approach, the most important results are the inclusion of a electron-phonon coupling non-diagonal in the electronic states and memory effects of the bath: First, the considered model system is introduced. Second, the time evolution of the statistical operator is expanded with respect to the external optical field. This expansion is the starting point to explain how a TCL theory can treat the response up to in a certain order in the external field. Third, new TCL equations, including bath memory effects, are derived and the problem of information loss in the reduced density matrix is analysed. For this purpose, new dimensions are added to the reduced statistical operator to compensate lack of information in comparison with the full statistical operator. The theory is benchmarked with a two level system and applied to a three level system including non-diagonal phonon coupling. In our analysis of pump-probe experiments, the bath memory is influenced by the system state occupied between pump and probe pulse. In particular, the memory of the bath influences the dephasing process of electronic coherences developing during the time interval between pump and probe pulses.
NASA Technical Reports Server (NTRS)
Callier, F. M.; Nahum, C. D.
1975-01-01
The series connection of two linear time-invariant systems that have minimal state space system descriptions is considered. From these descriptions, strict-system-equivalent polynomial matrix system descriptions in the manner of Rosenbrock are derived. They are based on the factorization of the transfer matrix of the subsystems as a ratio of two right or left coprime polynomial matrices. They give rise to a simple polynomial matrix system description of the tandem connection. Theorem 1 states that for the complete controllability and observability of the state space system description of the series connection, it is necessary and sufficient that certain 'denominator' and 'numerator' groups are coprime. Consequences for feedback systems are drawn in Corollary 1. The role of pole-zero cancellations is explained by Lemma 3 and Corollaires 2 and 3.
NASA Astrophysics Data System (ADS)
Panetta, R. J.; Hsiao, G.
2011-12-01
Trace levels of organic contaminants such as short alcohols and terpenoids have been shown to cause spectral interference in water isotope analysis by spectroscopic techniques. The result is degraded precision and accuracy in both δD and δ18O for samples such as beverages, plant extracts or slightly contaminated waters. An initial approach offered by manufacturers is post-processing software that analyzes spectral features to identify and flag contaminated samples. However, it is impossible for this software to accurately reconstruct the water isotope signature, thus it is primarily a metric for data quality. Here, we describe a novel in-line pyrolysis system (Micro-Pyrolysis Technology, MPT) placed just prior to the inlet of a cavity ring-down spectroscopy (CRDS) analyzer that effectively removes interfering organic molecules without altering the isotope values of the water. Following injection of the water sample, N2 carrier gas passes the sample through a micro-pyrolysis tube heated with multiple high temperature elements in an oxygen-free environment. The temperature is maintained above the thermal decomposition threshold of most organic compounds (≤ 900 oC), but well below that of water (~2000 oC). The main products of the pyrolysis reaction are non-interfering species such as elemental carbon and H2 gas. To test the efficacy and applicability of the system, waters of known isotopic composition were spiked with varying amounts of common interfering alcohols (methanol, ethanol, propanol, hexanol, trans-2-hexenol, cis-3-hexanol up to 5 % v/v) and common soluble plant terpenoids (carveol, linalool, geraniol, prenol). Spiked samples with no treatment to remove the organics show strong interfering absorption peaks that adversely affect the δD and δ18O values. However, with the MPT in place, all interfering absorption peaks are removed and the water absorption spectrum is fully restored. As a consequence, the δD and δ18O values also return to their original
BIOACCESSIBILITY TESTS ACCURATELY ESTIMATE ...
Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contaminated soils. Relative bioavailabilities were expressed by comparison with blood Pb concentrations in quail fed a Pb acetate reference diet. Diets containing soil from five Pb-contaminated Superfund sites had relative bioavailabilities from 33%-63%, with a mean of about 50%. Treatment of two of the soils with P significantly reduced the bioavailability of Pb. The bioaccessibility of the Pb in the test soils was then measured in six in vitro tests and regressed on bioavailability. They were: the “Relative Bioavailability Leaching Procedure” (RBALP) at pH 1.5, the same test conducted at pH 2.5, the “Ohio State University In vitro Gastrointestinal” method (OSU IVG), the “Urban Soil Bioaccessible Lead Test”, the modified “Physiologically Based Extraction Test” and the “Waterfowl Physiologically Based Extraction Test.” All regressions had positive slopes. Based on criteria of slope and coefficient of determination, the RBALP pH 2.5 and OSU IVG tests performed very well. Speciation by X-ray absorption spectroscopy demonstrated that, on average, most of the Pb in the sampled soils was sorbed to minerals (30%), bound to organic matter 24%, or present as Pb sulfate 18%. Ad
NASA Astrophysics Data System (ADS)
Afzali, R.; Ebrahimian, N.; Eghbalifar, B.
2016-10-01
By approximating the energy gap, entering nano-size effect via gap fluctuation and calculating the Green's functions and the space-spin density matrix, the dependence of quantum correlation (entanglement, discord and tripartite entanglement) on the relative distance of two electron spins forming Cooper pairs, the energy gap and the length of bulk and nano interacting Fermi system (a nodal d-wave superconductor) is determined. In contrast to a s-wave superconductor, quantum correlation of the system is sensitive to the change of the gap magnitude and strongly depends on the length of the grain. Also, quantum discord oscillates. Furthermore, the entanglement length and the correlation length are investigated. Discord becomes zero at a characteristic length of the d-wave superconductor.
NASA Technical Reports Server (NTRS)
Zhu, Dongming; Harder, Bryan
2016-01-01
Environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft turbine engine systems, because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. This paper presents current NASA EBC-CMC development emphases including: the coating composition and processing improvements, laser high heat flux-thermal gradient thermo-mechanical fatigue - environmental testing methodology development, and property evaluations for next generation EBC-CMC systems. EBCs processed with various deposition techniques including Plasma Spray, Electron Beam - Physical Vapor Deposition, and Plasma Spray Physical Vapor Deposition (PS-PVD) will be particularly discussed. The testing results and demonstrations of advanced EBCs-CMCs in complex simulated engine thermal gradient cyclic fatigue, oxidizing-steam and CMAS environments will help provide insights into the coating development strategies to meet long-term engine component durability goals.
NASA Astrophysics Data System (ADS)
Broin, Cathal Ó.; Nikolopoulos, L. A. A.
2017-02-01
In this thesis tutorial we discuss the R-matrix-incorporating-time ab initio theoretical framework for the solution of the time-dependent Schrödinger equation of one-electron atomic and molecular systems under strong electromagnetic fields. Within this approach, a division-of-space method is developed with the configuration space of the electron’s coordinates separated over two regions, the inner and outer regions. In the inner region the quantum system’s time-dependent wavefunction is expanded on the eigenstate basis set of its field-free Hamiltonian representation while in the outer region its grid representation is considered. The present tutorial describes in detail the theoretical formulation for one-electron quantum systems. Example calculations are discussed for atomic hydrogen, H, and the molecular hydrogen ion, {{{H}}}2+, in intense laser fields.
Costa, Carme; Tortosa, Raül; Vidal, Enric; Padilla, Danielle; Torres, Juan Maria; Ferrer, Isidre; Pumarola, Martí; Bassols, Anna
2009-11-01
Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy characterised by accumulation of resistant prion protein (PrP(BSE)), neuronal loss, spongiosus and glial cell proliferation. In this study, properties of the extracellular matrix (ECM) were investigated in boTg110 transgenic mice over-expressing the bovine cellular prion protein (PrP(c)) and infected with BSE. Using immunohistochemistry with Wisteria floribunda agglutinin as a specific marker for perineuronal nets (PNNs) and antibodies against aggrecan and hyaluronic acid binding protein, loss of ECM was correlated with PrP(BSE) accumulation and activation of astrocytes and microglia. PrP(BSE) accumulation and glial cell activation were detected from the earliest stages of the disease and increased in the terminal stages. Decreases in PNNs, aggrecan and hyaluronic acid were observed only in the terminal stages and correlated with the distribution of PrP(BSE) and activated glial cells. This study suggests that the loss of PNNs, aggrecan and hyaluronic acid is a consequence of PrP(BSE) accumulation. Degradation of ECM in BSE may be due to secretion of degradative enzymes by activated glial cells.
Ordering Unstructured Meshes for Sparse Matrix Computations on Leading Parallel Systems
NASA Technical Reports Server (NTRS)
Oliker, Leonid; Li, Xiaoye; Heber, Gerd; Biswas, Rupak
2000-01-01
The ability of computers to solve hitherto intractable problems and simulate complex processes using mathematical models makes them an indispensable part of modern science and engineering. Computer simulations of large-scale realistic applications usually require solving a set of non-linear partial differential equations (PDES) over a finite region. For example, one thrust area in the DOE Grand Challenge projects is to design future accelerators such as the SpaHation Neutron Source (SNS). Our colleagues at SLAC need to model complex RFQ cavities with large aspect ratios. Unstructured grids are currently used to resolve the small features in a large computational domain; dynamic mesh adaptation will be added in the future for additional efficiency. The PDEs for electromagnetics are discretized by the FEM method, which leads to a generalized eigenvalue problem Kx = AMx, where K and M are the stiffness and mass matrices, and are very sparse. In a typical cavity model, the number of degrees of freedom is about one million. For such large eigenproblems, direct solution techniques quickly reach the memory limits. Instead, the most widely-used methods are Krylov subspace methods, such as Lanczos or Jacobi-Davidson. In all the Krylov-based algorithms, sparse matrix-vector multiplication (SPMV) must be performed repeatedly. Therefore, the efficiency of SPMV usually determines the eigensolver speed. SPMV is also one of the most heavily used kernels in large-scale numerical simulations.
Galazo, Maria J; Martinez-Cerdeño, Verónica; Porrero, César; Clascá, Francisco
2008-02-01
Inputs to the layer I apical dendritic tufts of pyramidal cells are crucial in "top-down" interactions in the cerebral cortex. A large population of thalamocortical cells, the "matrix" (M-type) cells, provides a direct robust input to layer I that is anatomically and functionally different from the thalamocortical input to layer VI. The developmental timecourse of M-type axons is examined here in rats aged E (embryonic day) 16 to P (postnatal day) 30. Anterograde techniques were used to label axons arising from 2 thalamic nuclei mainly made up of M-type cells, the Posterior and the Ventromedial. The primary growth cones of M-type axons rapidly reached the subplate of dorsally situated cortical areas. After this, interstitial branches would sprout from these axons under more lateral cortical regions to invade the overlying cortical plate forming secondary arbors. Moreover, retrograde labeling of M-type cell somata in the thalamus after tracer deposits confined to layer I revealed that large numbers of axons from multiple thalamic nuclei had already converged in a given spot of layer I by P3. Because of early ingrowth in such large numbers, interactions of M-type axons may significantly influence the early development of cortical circuits.
Expression and purification of the matrix protein of Nipah virus in baculovirus insect cell system.
Masoomi Dezfooli, Seyedehsara; Tan, Wen Siang; Tey, Beng Ti; Ooi, Chien Wei; Hussain, Siti Aslina
2016-01-01
Nipah virus (NiV) causes fatal respiratory illness and encephalitis in humans and animals. The matrix (M) protein of NiV plays an important role in the viral assembly and budding process. Thus, an access to the NiV M protein is vital to the design of viral antigens as diagnostic reagents. In this study, recombinant DNA technology was successfully adopted in the cloning and expression of NiV M protein. A recombinant expression cassette (baculovirus expression vector) was used to encode an N-terminally His-tagged NiV M protein in insect cells. A time-course study demonstrated that the highest yield of recombinant M protein (400-500 μg) was expressed from 107 infected cells 3 days after infection. A single-step purification method based on metal ion affinity chromatography was established to purify the NiV M protein, which successfully yielded a purity level of 95.67% and a purification factor of 3.39. The Western blotting and enzyme-linked immunosorbent assay (ELISA) showed that the purified recombinant M protein (48 kDa) was antigenic and reacted strongly with the serum of a NiV infected pig.
NASA Astrophysics Data System (ADS)
Yao, Y. X.; Liu, C.; Liu, J.; Lu, W. C.; Wang, C. Z.; Ho, K. M.
2013-03-01
The recently introduced correlation matrix renormalization approximation (CMRA) was further developed by adopting a completely factorizable form for the renormalization z-factors, which assumes the validity of the Wick's theorem with respect to Gutzwiller wave function. This approximation (CMR-II) shows better dissociation behavior than the original one (CMR-I) based on the straightforward generalization of the Gutzwiller approximation to two-body interactions. We further improved the performance of CMRA by redefining the z-factors as a function of f(z) in CMR-II, which we call CMR-III. We obtained an analytical expression of f(z) by enforcing the equality in energy functional between CMR-III and full configuration interaction for the benchmark minimal basis H2. We show that CMR-III yields quite good binding energies and dissociation behaviors for various hydrogen clusters with converged basis set. Finally, we apply CMR-III to hydrogen crystal phases and compare the results with quantum Monte Carlo. Research supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering. Ames Laboratory is operated for the U.S. DOE by Iowa State University under Contract No. DE-AC02-07CH11358.
Expert system training and control based on the fuzzy relation matrix
NASA Technical Reports Server (NTRS)
Ren, Jie; Sheridan, T. B.
1991-01-01
Fuzzy knowledge, that for which the terms of reference are not crisp but overlapped, seems to characterize human expertise. This can be shown from the fact that an experienced human operator can control some complex plants better than a computer can. Proposed here is fuzzy theory to build a fuzzy expert relation matrix (FERM) from given rules or/and examples, either in linguistic terms or in numerical values to mimic human processes of perception and decision making. The knowledge base is codified in terms of many implicit fuzzy rules. Fuzzy knowledge thus codified may also be compared with explicit rules specified by a human expert. It can also provide a basis for modeling the human operator and allow comparison of what a human operator says to what he does in practice. Two experiments were performed. In the first, control of liquid in a tank, demonstrates how the FERM knowledge base is elicited and trained. The other shows how to use a FERM, build up from linguistic rules, and to control an inverted pendulum without a dynamic model.
Accurate spectral color measurements
NASA Astrophysics Data System (ADS)
Hiltunen, Jouni; Jaeaeskelaeinen, Timo; Parkkinen, Jussi P. S.
1999-08-01
Surface color measurement is of importance in a very wide range of industrial applications including paint, paper, printing, photography, textiles, plastics and so on. For a demanding color measurements spectral approach is often needed. One can measure a color spectrum with a spectrophotometer using calibrated standard samples as a reference. Because it is impossible to define absolute color values of a sample, we always work with approximations. The human eye can perceive color difference as small as 0.5 CIELAB units and thus distinguish millions of colors. This 0.5 unit difference should be a goal for the precise color measurements. This limit is not a problem if we only want to measure the color difference of two samples, but if we want to know in a same time exact color coordinate values accuracy problems arise. The values of two instruments can be astonishingly different. The accuracy of the instrument used in color measurement may depend on various errors such as photometric non-linearity, wavelength error, integrating sphere dark level error, integrating sphere error in both specular included and specular excluded modes. Thus the correction formulas should be used to get more accurate results. Another question is how many channels i.e. wavelengths we are using to measure a spectrum. It is obvious that the sampling interval should be short to get more precise results. Furthermore, the result we get is always compromise of measuring time, conditions and cost. Sometimes we have to use portable syste or the shape and the size of samples makes it impossible to use sensitive equipment. In this study a small set of calibrated color tiles measured with the Perkin Elmer Lamda 18 and the Minolta CM-2002 spectrophotometers are compared. In the paper we explain the typical error sources of spectral color measurements, and show which are the accuracy demands a good colorimeter should have.
Digraph Matrix Analysis for systems interactions at Indian Point Unit 3. Volume 1
Alesso, H.P.; Altenbach, T.J.; Prassinos, P.G.; Lappa, D.A.; Kimura, C.Y.; Patenaude, C.J.; Sacks, I.J.; Ashmore, B.C.; Fromme, D.C.; Hershberger, M.V.
1986-01-01
This report documents the analysis of the Indian Point Plant, Unit 3 (IP-3) for adverse systems interactions using DMA. The primary objective of the study was to compare the effectiveness of DMA in finding systems interactions. To this end a parallel study was funded at Brookhaven National Laboratory (BNL). The results of this study and the BNL study will then be compared by NRC to the results of a similar study performed by the Power Authority of the State of New York. A secondary objective of this study was to determine systems interactions in selected combinations of safety systems at IP-3. 24 refs., 22 figs., 29 tabs.
Witsch, Thilo J.; Turowski, Paweł; Sakkas, Elpidoforos; Niess, Gero; Becker, Simone; Herold, Susanne; Mayer, Konstantin; Vadász, István; Roberts, Jesse D.; Seeger, Werner
2013-01-01
Bronchopulmonary dysplasia (BPD) is a common and serious complication of premature birth, characterized by a pronounced arrest of alveolar development. The underlying pathophysiological mechanisms are poorly understood although perturbations to the maturation and remodeling of the extracellular matrix (ECM) are emerging as candidate disease pathomechanisms. In this study, the expression and regulation of three members of the lysyl hydroxylase family of ECM remodeling enzymes (Plod1, Plod2, and Plod3) in clinical BPD, as well as in an experimental animal model of BPD, were addressed. All three enzymes were localized to the septal walls in developing mouse lungs, with Plod1 also expressed in the vessel walls of the developing lung and Plod3 expressed uniquely at the base of developing septa. The expression of plod1, plod2, and plod3 was upregulated in the lungs of mouse pups exposed to 85% O2, an experimental animal model of BPD. Transforming growth factor (TGF)-β increased plod2 mRNA levels and activated the plod2 promoter in vitro in lung epithelial cells and in lung fibroblasts. Using in vivo neutralization of TGF-β signaling in the experimental animal model of BPD, TGF-β was identified as the regulator of aberrant plod2 expression. PLOD2 mRNA expression was also elevated in human neonates who died with BPD or at risk for BPD, compared with neonates matched for gestational age at birth or chronological age at death. These data point to potential roles for lysyl hydroxylases in normal lung development, as well as in perturbed late lung development associated with BPD. PMID:24285264
Gialafos, Elias J.; Moyssakis, Ioannis; Psaltopoulou, Theodora; Papadopoulos, Dimitrios P.; Perea, Despoina; Vlasis, Kostantinos; Kostopoulos, Charalampos; Votteas, Vassilios; Sfikakis, Petros P.
2008-01-01
Decreased levels of matrix metalloproteinases (MMPs) or excess levels of their tissue inhibitors (TIMPs) may contribute to dysregulation of extracellular matrix turnover in systemic sclerosis (SSc). In a cross-sectional study of 106 SSc patients, we measured serum levels of TIMP-4 which is preferentially expressed in cardiovascular structures and searched for correlations with simultaneously performed echocardiography measurements of pulmonary artery systolic pressure (PASP), myocardial performance, and pulmonary function tests. TIMP-4, but not MMP-9, levels were significantly raised in patients with SSc than controls. However, in the subgroup of patients with PASP measurements lower to 40 mmHg (n = 69), TIMP-4 levels were comparable to controls irrespective of the presence of diffuse or limited skin involvement, or lung fibrosis. Individual PASP measurements suggestive of pulmonary hypertension were associated with increased TIMP-4 serum levels (P = .03), independently of age, extent of skin sclerosis, or lung fibrosis, suggesting a cardiopulmonary vasculature-specific role of TIMP-4 activation in SSc. PMID:19190762
Kulp, Kristen S; Fortson, Susan L; Knize, Mark G; Felton, James S
2003-12-01
To understand the impact of variation in digestion parameters on the release of heterocyclic amines naturally formed during cooking, we developed and characterized a model system to assess the effect of amylase, pepsin, and pancreatin on digestion of well-done chicken. The amounts of MeIQx, DiMeIQx, IFP, and PhIP in the liquid portion of the digestate were compared to levels in the undigested meat to determine the percentage released (accessible fraction). Incubating the meat with amylase and pepsin did not change the accessibility of HAs when compared to incubation with water alone. In contrast, increasing amounts of pancreatin increased the accessibility up to 6.4-fold. Comparing the amounts of the HAs in the liquid to the solid fraction showed that there was more MeIQx, DiMeIQx, and IFP in the liquid fraction. In contrast, PhIP was equally divided between the solid and liquid fractions. For all four compounds, increasing the doneness of the meat decreased the amount of the compound accessible from the meat matrix. Our data suggest that bioaccessability of HAs may vary according to the polarity of the individual HAs and also may depend upon the doneness of the meat. These results may have important ramifications for human feeding studies, which assume that the total amount of each HA in the meat matrix is equally bioavailable.
NASA Astrophysics Data System (ADS)
Li, Yonggao; Zhou, Yan; Yuan, Baoshan; Deng, Zhongchao; Zhang, Boyu; Li, Yuan; Deng, Wei; Wang, Haoxi; Yi, Jiang; HL-2A Team
2016-12-01
A new electron density profile reconstruction procedure based on the PARK-matrix method has been firstly exploited for the multi-chord formic acid (HCOOH, λ=432.5 μm) laser interferometry system on the HL-2A tokamak. According to the geometric coordinates of the magnetic surfaces reconstructed by the CF (current fitting) code and the assumption that the electron density between two adjacent magnetic surfaces is a constant, the local electron density is calculated layer by layer, and the electron density profile ne(Z) can be determined, as well as the density profile ne(R). The simulation result indicates that the error of the PARK-matrix method is acceptable for the four-chord HCOOH laser interferometer. In the applications, it shows that the reconstructed electron density profile agrees well with the microwave reflectometry measurement, and the sawtooth reversion radius is consistent with that deduced from the soft X-ray signals. Meanwhile, the electron density profiles with electron cyclotron resonance heating (ECRH) and supersonic molecular beam injection (SMBI) are also reconstructed and analyzed. supported by the National Magnetic Confinement Fusion Science Program of China (No. 2014GB109001), and National Natural Science Foundation of China (Nos. 11505053 and 11275059)
NASA Astrophysics Data System (ADS)
Kim, Jae Wook
2013-05-01
This paper proposes a novel systematic approach for the parallelization of pentadiagonal compact finite-difference schemes and filters based on domain decomposition. The proposed approach allows a pentadiagonal banded matrix system to be split into quasi-disjoint subsystems by using a linear-algebraic transformation technique. As a result the inversion of pentadiagonal matrices can be implemented within each subdomain in an independent manner subject to a conventional halo-exchange process. The proposed matrix transformation leads to new subdomain boundary (SB) compact schemes and filters that require three halo terms to exchange with neighboring subdomains. The internode communication overhead in the present approach is equivalent to that of standard explicit schemes and filters based on seven-point discretization stencils. The new SB compact schemes and filters demand additional arithmetic operations compared to the original serial ones. However, it is shown that the additional cost becomes sufficiently low by choosing optimal sizes of their discretization stencils. Compared to earlier published results, the proposed SB compact schemes and filters successfully reduce parallelization artifacts arising from subdomain boundaries to a level sufficiently negligible for sophisticated aeroacoustic simulations without degrading parallel efficiency. The overall performance and parallel efficiency of the proposed approach are demonstrated by stringent benchmark tests.
Giesbertz, K. J. H.; Gritsenko, O. V.; Baerends, E. J.
2014-05-14
Recently, we have demonstrated that the problems finding a suitable adiabatic approximation in time-dependent one-body reduced density matrix functional theory can be remedied by introducing an additional degree of freedom to describe the system: the phase of the natural orbitals [K. J. H. Giesbertz, O. V. Gritsenko, and E. J. Baerends, Phys. Rev. Lett. 105, 013002 (2010); K. J. H. Giesbertz, O. V. Gritsenko, and E. J. Baerends, J. Chem. Phys. 133, 174119 (2010)]. In this article we will show in detail how the frequency-dependent response equations give the proper static limit (ω → 0), including the perturbation in the chemical potential, which is required in static response theory to ensure the correct number of particles. Additionally we show results for the polarizability for H{sub 2} and compare the performance of two different two-electron functionals: the phase-including Löwdin–Shull functional and the density matrix form of the Löwdin–Shull functional.
New pole placement algorithm - Polynomial matrix approach
NASA Technical Reports Server (NTRS)
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.
Kumar, M Praveen; Patil, Suneel G; Dheeraj, Bhandari; Reddy, Keshav; Goel, Dinker; Krishna, Gopi
2015-01-01
Background: The difficulty in obtaining an acceptable impression increases exponentially as the number of abutments increases. Accuracy of the impression material and the use of a suitable impression technique are of utmost importance in the fabrication of a fixed partial denture. This study compared the accuracy of the matrix impression system with conventional putty reline and multiple mix technique for individual dies by comparing the inter-abutment distance in the casts obtained from the impressions. Materials and Methods: Three groups, 10 impressions each with three impression techniques (matrix impression system, putty reline technique and multiple mix technique) were made of a master die. Typodont teeth were embedded in a maxillary frasaco model base. The left first premolar was removed to create a three-unit fixed partial denture situation and the left canine and second premolar were prepared conservatively, and hatch marks were made on the abutment teeth. The final casts obtained from the impressions were examined under a profile projector and the inter-abutment distance was calculated for all the casts and compared. Results: The results from this study showed that in the mesiodistal dimensions the percentage deviation from master model in Group I was 0.1 and 0.2, in Group II was 0.9 and 0.3, and Group III was 1.6 and 1.5, respectively. In the labio-palatal dimensions the percentage deviation from master model in Group I was 0.01 and 0.4, Group II was 1.9 and 1.3, and Group III was 2.2 and 2.0, respectively. In the cervico-incisal dimensions the percentage deviation from the master model in Group I was 1.1 and 0.2, Group II was 3.9 and 1.7, and Group III was 1.9 and 3.0, respectively. In the inter-abutment dimension of dies, percentage deviation from master model in Group I was 0.1, Group II was 0.6, and Group III was 1.0. Conclusion: The matrix impression system showed more accuracy of reproduction for individual dies when compared with putty reline
Anisotropic dielectric properties of two-dimensional matrix in pseudo-spin ferroelectric system
NASA Astrophysics Data System (ADS)
Kim, Se-Hun
2016-10-01
The anisotropic dielectric properties of a two-dimensional (2D) ferroelectric system were studied using the statistical calculation of the pseudo-spin Ising Hamiltonian model. It is necessary to delay the time for measurements of the observable and the independence of the new spin configuration under Monte Carlo sampling, in which the thermal equilibrium state depends on the temperature and size of the system. The autocorrelation time constants of the normalized relaxation function were determined by taking temperature and 2D lattice size into account. We discuss the dielectric constants of a two-dimensional ferroelectric system by using the Metropolis method in view of the Slater-Takagi defect energies.
Biofabrication of a co-culture system in an osteoid-like hydrogel matrix.
Zehnder, Tobias; Boccaccini, Aldo; Detsch, Rainer
2017-03-07
Biofabrication aims to develop functional, biological constructs using automated processes (additive manufacturing, AM) involving different cell types and biomaterials [1]. As bone tissue is based on the crosstalk between osteoblasts and osteoclasts at least, evaluating cell-cell and cell-material interactions is of interest to understand bone remodeling. There is increasing interest in the role of osteoclasts not only considering bone resorption, but also their influence on the proliferation, migration and differentiation of osteoblasts. Osteoid-like, non-mineralized matrix is used here for the 3D cultivation of osteoblast and osteoclast progenitor cells to evaluate interactions in an early stage of bone formation. The AM technology bioplotting was used to tailor a 3D environment with defined properties. These results could be helpful to transfer this approach to the fabrication of bone tissue in regenerative medicine approaches. Gelatin is derived from collagen, which is the main phase of osteoid. Oxidized alginate-gelatin crosslinked hydrogel was used to immobilize osteoblastic (ST2) and osteoclastic (RAW) progenitor cells. Cell viability and number, the expression of different proteins like alkaline phosphatase (ALP), osteopontin (OPN) and tartrate resistant acid phosphatase (TRAP) were investigated. Release of vascular endothelial growth factor (VEGF) by the immobilized cells was analyzed. Microscopy techniques were used to evaluate cell morphology during incubation of 21 days. The biofabrication process was compatible with the cells. Cells migrated, proliferated and expressed their specific proteins indicating cell differentiation. The co-culture showed increased OPN concentration, which is a major protein of the osteoid involved in the mineralization process. TRAP activity was increased compared to single culture. ST2 single culture showed higher ALP activity compared to the co-culture. VEGF concentration of the co-culture was strongly increased. The results
Approximate method of free energy calculation for spin system with arbitrary connection matrix
NASA Astrophysics Data System (ADS)
Kryzhanovsky, Boris; Litinskii, Leonid
2015-01-01
The proposed method of the free energy calculation is based on the approximation of the energy distribution in the microcanonical ensemble by the Gaussian distribution. We hope that our approach will be effective for the systems with long-range interaction, where large coordination number q ensures the correctness of the central limit theorem application. However, the method provides good results also for systems with short-range interaction when the number q is not so large.
Solving systems of linear equations by GPU-based matrix factorization in a Science Ground Segment
NASA Astrophysics Data System (ADS)
Legendre, Maxime; Schmidt, Albrecht; Moussaoui, Saïd; Lammers, Uwe
2013-11-01
Recently, Graphics Cards have been used to offload scientific computations from traditional CPUs for greater efficiency. This paper investigates the adaptation of a real-world linear system solver, which plays a central role in the data processing of the Science Ground Segment of ESA's astrometric Gaia mission. The paper quantifies the resource trade-offs between traditional CPU implementations and modern CUDA based GPU implementations. It also analyses the impact on the pipeline architecture and system development. The investigation starts from both a selected baseline algorithm with a reference implementation and a traditional linear system solver and then explores various modifications to control flow and data layout to achieve higher resource efficiency. It turns out that with the current state of the art, the modifications impact non-technical system attributes. For example, the control flow of the original modified Cholesky transform is modified so that locality of the code and verifiability deteriorate. The maintainability of the system is affected as well. On the system level, users will have to deal with more complex configuration control and testing procedures.
Cross sections for n+{sup 14}N from an R-matrix analysis of the {sup 15}N system
Hale, G.M.; Young, P.G.; Chadwick, M.B.
1994-06-01
As part of the Hiroshima-Nagasaki Dose Reevaluation Program, a new evaluation of the neutron cross sections for {sup 14}N was made for ENDF/B-VI, based at energies below 2.5 MeV on a multichannel R-matrix analysis of reactions in the {sup 15}N system. The types of data used in the analysis, and the resulting cross sections and resonance structure for {sup 15}N are briefly described. The resonant features of the neutron cross sections were especially well determined by including precise, high-resolution neutron total cross section measurements from ORNL. While the new evaluated cross section appear to be significant improvements over the earlier ones, they still need to be tested more extensively against recent measurements of the differential elastic cross section from Oak Ridge.
Time-dependent analytical R-matrix approach for strong-field dynamics. I. One-electron systems
NASA Astrophysics Data System (ADS)
Torlina, Lisa; Smirnova, Olga
2012-10-01
We develop a flexible analytical approach to describe strong-field dynamics in atoms and molecules. The approach is based on the ideas of the R-matrix method. Here, we illustrate and validate our approach by applying it to systems with one active electron bound by the Coulomb potential and benchmark our results against the standard theory of Perelomov, Popov, and Terent'ev [Sov. Phys. JETP0021-903710.1007/BF01132710 23, 924 (1966)]. We discuss corrections to the ionization amplitude associated with the interplay of the Coulomb potential and the laser field on the sub-laser cycle time scale and the shape of the tunneling wave packets associated with different instants of ionization.
Microgravity effects on water supply and substrate properties in porous matrix root support systems
NASA Technical Reports Server (NTRS)
Bingham, G. E.; Jones, S. B.; Or, D.; Podolski, I. G.; Levinskikh, M. A.; Sytchov, V. N.; Ivanova, T.; Kostov, P.; Sapunova, S.; Dandolov, I.; Bubenheim, D. B.; Jahns, G.; Campbell, W. F. (Principal Investigator)
2000-01-01
The control of water content and water movement in granular substrate-based plant root systems in microgravity is a complex problem. Improper water and oxygen delivery to plant roots has delayed studies of the effects of microgravity on plant development and the use of plants in physical and mental life support systems. Our international effort (USA, Russia and Bulgaria) has upgraded the plant growth facilities on the Mir Orbital Station (OS) and used them to study the full life cycle of plants. The Bulgarian-Russian-developed Svet Space Greenhouse (SG) system was upgraded on the Mir OS in 1996. The US developed Gas Exchange Measurement System (GEMS) greatly extends the range of environmental parameters monitored. The Svet-GEMS complex was used to grow a fully developed wheat crop during 1996. The growth rate and development of these plants compared well with earth grown plants indicating that the root zone water and oxygen stresses that have limited plant development in previous long-duration experiments have been overcome. However, management of the root environment during this experiment involved several significant changes in control settings as the relationship between the water delivery system, water status sensors, and the substrate changed during the growth cycles. c 2001 Published by Elsevier Science Ltd. All rights reserved.
Kerimoğlu, Oya; Keskin, Ebru; Dortunç, Betül; Anah, Sela
2013-01-01
Transdermal therapeutic systems (TTS) containing captopril were developed by using synthetic and pH independent polymers, Eudragit RL 100 and RS 100. The formulations were characterized in terms of their appearance, thickness, captopril content, in vitro release rate and diffusion profiles. In vitro release studies demonstrated controlled release for each formulation developed. In viro and ex vivo diffusion rate studies were performed through various synthetic membranes with different thickness, pore size and type (hydrophilic and hydrophobic) and through human skin by using Franz diffusion cells. Type of membrane and composition of the formulation affected the diffusion profiles of captopril from the transdermal therapeutic systems. Transdermal therapeutic systems containing captopril were successfully prepared and especially two of the formulations (F15 and F16) are considered to be suitable to administer captopril via skin.
ERIC Educational Resources Information Center
New York State Office of the Comptroller, Albany.
The New York State Board of Education's Division of School Safety is responsible for maintaining a safe and secure environment to ensure that schools are free from disruption. This report presents findings of an audit that investigated whether the division's incident reporting system database accurately captured all school safety incidents that…
Sorption characteristics of pesticides on matrix substrates used in biopurification systems.
De Wilde, Tineke; Spanoghe, Pieter; Ryckeboer, Jaak; Jaeken, Peter; Springael, Dirk
2009-03-01
On-farm biopurification systems were developed to remove pesticides from contaminated water generated at the farmyard. An important process in the system's efficiency is the sorption of pesticides to the substrates used in the biopurification systems. The composition and type of material present in the biobed are crucial for retention of chemicals. This study investigated the sorption of linuron, isoproturon, metalaxyl, isoxaben, bentazon and lenacil on substrates commonly used in a biopurification system, i.e. cow manure, straw, willow chopping, soil, coconut chips, garden waste compost, and peat mix. Linear, Freundlich, and Langmuir sorption isotherms were fitted to the obtained data. The best fit was obtained with the Freundlich model. More immobile pesticides (i.e. linuron and isoxaben) tended to associate with the organic substrate, while more mobile pesticides partition in the water (i.e. bentazon). According to sorption capacity, the substrates could be classified as peat mix > compost, coco chips, straw > cow manure, willow chopping > sandy loam soil. Sorption capacity was positively correlated with the organic carbon content, CaO and the cation exchange capacity. Furthermore, no significant differences in sorption could be found between technical and formulated isoproturon and bentazon. Moreover, the individual sorption coefficient K(d) was additive, which means that individual sorption coefficients can be used to calculate the sorption coefficients of a mixture of substrates. What concerns the mutual interaction of pesticides it could be observed that the sorption of linuron and metalaxyl was significantly lower in combination with isoproturon and bentazon, while the latter pesticides were not influenced by the presence of linuron and metalaxyl. As guidelines, firstly, it could be stated that using the most sorbing materials such as peat mix, might significantly increase the biopurification systems efficiency. Secondly, the treatment of very mobile
Matrix-isolated bismuth. I. The A --> X band system of Bi2 in solid argon
NASA Astrophysics Data System (ADS)
Ahmed, Fakhruddin; Nixon, Eugene R.
1981-02-01
The A→X fluorescence system of the Bi2 molecule in solid argon has been explored by means of tunable dye laser radiation. About 135 bands involving A state levels from v'=0 to v'=6 and X state levels up to v''=26 are observed. Analysis yields ωe values of 133.4 and 174.3 cm-1 for the A and X states, respectively, and a band system origin at 17 719 cm-1. The Raman spectrum of the fundamental vibration and two overtones of Bi2 appear along with the fluorescence.
Kim, Yeongsic; Park, Kang Gyun; Lee, Kyungwon
2015-01-01
Background We evaluated the coincidence rate between Vitek MS system (bioMérieux, France) and Vitek 2 in identifying uropathogens directly from urine specimens. Methods Urine specimens submitted to our microbiology laboratory between July and September 2013 for Gram staining and bacterial culture were analyzed. Bacterial identification was performed by using the conventional method. Urine specimens showing a single morphotype by Gram staining were processed by culturing and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Of 2,370 urine specimens, 251 showed a single morphotype on Gram staining, and among them, 202 were available for MALDI-TOF MS. Results In these 202 specimens, colony growth was observed in 189 specimens, and 145 specimens had significant growth of single-colony morphotype in culture. One hundred and ten (75.9%) of them had colony counts of ≥105 colony-forming units (CFU)/mL and included 71 enteric gram-negative bacteria (GNB), 5 glucose-non-fermenting GNB, 9 gram-positive cocci (GPC), and 25 yeasts. Furthermore, 70 (98.6%), 3 (60.0%), 4 (44.4%), and 5 (20.0%), respectively, of these were correctly identified by Vitek MS. Thirty-one specimens (21.4%; 11 GNB, 7 GPC, 12 yeasts, and 1 gram-positive bacillus) had colony counts of 104-105 CFU/mL. Four specimens (2.8%) yielded colony counts of 103-104 CFU/mL. Conclusions Vitek MS showed high rate of accuracy for the identification of GNB in urine specimens (≥105 CFU/mL). This could become a rapid and accurate diagnostic method for urinary tract infection caused by GNB. However, for the identification of GPC and yeasts, further studies on appropriate pre-treatment are warranted. PMID:26131413
Li, Zhao; Xu, Heming; Li, Shujuan; Li, Qijun; Zhang, Wenji; Ye, Tiantian; Yang, Xinggang; Pan, Weisan
2014-01-30
The study was aimed to develop a novel gastro-floating multiparticulate system based on a porous and low-density matrix core with excellent floatability. The gastro-floating pellets (GFP) were composed of a porous matrix core, a drug loaded layer (DIP and HPMC), a sub-coating layer (HPMC) and a retarding layer (Eudragit(®) NE 30D). The porous matrix cores were evaluated in specific. EC was chosen as the matrix membrane for its rigidity and minimal expansion to large extent. The porous matrix core was achieved by the complete release of the bulk water soluble excipient from the EC coated beads, and mannitol was selected as the optimal water soluble excipient. SEM photomicrographs confirmed the structure of porous matrix cores. The compositions of GFP were investigated and optimized by orthogonal array design. The optimized formulation could sustain the drug release for 12h and float on the dissolution medium for at least 12h without lag time to float. The pharmacokinetic study was conducted in beagle dogs, and the relative bioavailability of the test preparation was 193.11±3.43%. In conclusion, the novel gastro-floating pellets can be developed as a promising approach for the gastro-retentive drug delivery systems.
Theoretical studies of the reaction dynamics of the matrix-isolated F2+cis-d2 -ethylene system
NASA Astrophysics Data System (ADS)
Raff, Lionel M.
1991-12-01
The molecular dynamics of the F2+cis-d2 -ethylene addition reaction and the subsequent decomposition dynamics of the vibrationally excited 1,2-difluoroethane-d2 product isolated in Ar or Xe matrices at 12 K are investigated using trajectory methods that incorporate nonstatistical sampling to enhance the reaction probabilities. The matrix is represented by a face-centered-cubic crystal containing 125 unit cells with 666 lattice atoms in a cubic (5×5×5) arrangement. Both interstitial and substitutional sites for the F2/cis-d2 -ethylene pair are examined. Transport effects of the bulk are simulated using the velocity reset method introduced by Riley, Coltrin, and Diestler [J. Chem. Phys. 88, 5934 (1988)]. The potential-energy hypersurface for the system is written as the separable sum of a lattice potential, a lattice-substrate interaction, and a gas-phase potential for 1,2-difluoroethane-d2. The first two of these have pairwise form, while the 1,2-difluoroethane-d2 potential is identical to that employed previously to study the unimolecular reaction dynamics of matrix-isolated 1,2-difluoroethane-d4 [J. Chem. Phys. 93, 3160 (1990)]. The major F2+cis-d2 -ethylene reaction mechanism involves a four-center, concerted αβ addition across the C=C double bond. A small contribution from an atomic addition mechanism that initially forms fluoroethyl and fluorine radicals is observed in a xenon matrix, but not in argon. Subsequent to the formation of 1,2-difluoroethane-d2, the observed dynamic processes are vibrational relaxation to the lattice phonon modes, orientational exchange, and HF or DF elimination reactions. Vibrational relaxation is found to be very similar to that observed previously for 1,2-difluoroethane-d4. The process is well described by a first-order rate law with rate coefficients in the range 0.046-0.069 ps-1. The distribution of rate coefficients, as well as the averages, are nearly identical for Ar and Xe lattices. Very little difference is found between
Solid-state active switch matrix for high energy, moderate power battery systems
Deal, Larry; Paris, Peter; Ye, Changqing
2016-06-07
A battery management system employs electronic switches and capacitors. No traditional cell-balancing resistors are used. The BMS electronically switches individual cells into and out of a module of cells in order to use the maximum amount of energy available in each cell and to completely charge and discharge each cell without overcharging or under-discharging.
Control Systems Analysis and Design via Matrix Inequalities and Interior Point Methods
2007-11-02
Springer-Verlag, 4th edition, 1997. [JBK+96] G. B. Jävorzky, S. Boyd, I. Kollär, L. Vandenberghe, and S.-P. Wu. Opti- mal excitation signal design for...multiple-output channels. To appear in IEEE GLOBECOM, 1998. [PS96] B. W. Parkinson and J. J. Spilker, Jr. Global positioning system : theory and
Stability of headspace volatiles in a ‘Fallglo’ tangerine juice matrix system at room temperature
Technology Transfer Automated Retrieval System (TEKTRAN)
Gas chromatography systems are usually equipped with autosamplers. Samples held in the autosampler tray can stay up to one day or longer at room temperature, if the tray is not equipped with a cooling mechanism. The objective of this research was to determine if holding samples at room temperature i...
NASA Technical Reports Server (NTRS)
Zhu, Dongming
2015-01-01
Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. This paper will emphasize advanced environmental barrier coating developments for SiCSiC turbine airfoil components, by using advanced coating compositions and processing, in conjunction with mechanical and environment testing and durability validations. The coating-CMC degradations and durability in the laboratory simulated engine fatigue-creep and complex operating environments are being addressed. The effects of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the degradation mechanisms of the environmental barrier coating systems will be discussed. The results help understand the advanced EBC-CMC system performance, aiming at the durability improvements of more robust, prime-reliant environmental barrier coatings for successful applications of the component technologies and lifing methodologies.
Matrix product states for gauge field theories.
Buyens, Boye; Haegeman, Jutho; Van Acoleyen, Karel; Verschelde, Henri; Verstraete, Frank
2014-08-29
The matrix product state formalism is used to simulate Hamiltonian lattice gauge theories. To this end, we define matrix product state manifolds which are manifestly gauge invariant. As an application, we study (1+1)-dimensional one flavor quantum electrodynamics, also known as the massive Schwinger model, and are able to determine very accurately the ground-state properties and elementary one-particle excitations in the continuum limit. In particular, a novel particle excitation in the form of a heavy vector boson is uncovered, compatible with the strong coupling expansion in the continuum. We also study full quantum nonequilibrium dynamics by simulating the real-time evolution of the system induced by a quench in the form of a uniform background electric field.
1990-12-07
Technology, Haifa, 1968. 45 10. Bhatia , Rajendra , Perturbation Bounds for Matrix Eigenvalues, Pitman Research Notes in Mathematics, H. Brezis, R. G. Douglas...is currently in press in the SIAM Journal of Matrix Analysis . The proof sheets have been corrected and returned to the editor during the period of this...appear. [3] R. A. Horn and C. R. Johnson, Matrix Analysis , Cambridge University Press, New York, 1985. 141 M. Marcus and N. Khan, A note on the
2007-06-01
1: Interview with: Jane Doe ACME Corporation Chief Engineer Date: 11/2/01 Q: What are some of your challenges in coordinating design activities? Codes...Canwnentfl Jb3r ATh level yet so obviously it wasn’t an R, an A-5-R issue)......... Stakeholders. MD> comunicates with> Q. Do you have contact with any...some ways, the goal was to develop a suite of systems that were akin to the weapons of corporate warfare, the Blackberry and Treo (other multipurpose
Accurate high-pressure and high-temperature effective pair potentials for the systems N2-N and O2-O
NASA Astrophysics Data System (ADS)
van Thiel, M.; Ree, F. H.
1996-04-01
Statistical mechanical chemical equilibrium calculations of N2 and O2 show that these molecules dissociate behind strong shock waves. Our determination of accurate intermolecular potentials has required the consideration of the dissociation products N and O. Our previous theoretical efforts to predict the thermodynamic properties of these molecules relied in part on corresponding states theory and shock wave data of argon, without consideration of the dissociation products. Recent high-pressure Hugoniot measurements, however, allowed a more accurate determination of the potentials and the explicit inclusion of the dissociation products. The best fit to the data is obtained with the exponential-6 coefficients, for O2-O2: ɛ/k=125 K, r*=3.86 Å, α=13.2; for O-O: ɛ/k=700 K, r*=2.40 Å, α=11.0; for N2-N2: ɛ/k=293 K, r*=3.91 Å, α=11.5; and for N-N: ɛ/k=600 K, r*=2.47 Å, α=10.0. The unlike pair interactions are obtained from these like interactions with a modified Lorentz-Berthelot rule. The coefficients in the modified Lorentz-Berthelot equations are k/l/m=1/1/0.93 for O2-O- and k/l/m=1/1/0.90 for N2-N interactions.
Sevcsik, E.; Pabst, G.; Richter, W.; Danner, S.; Amenitsch, H.; Lohner, K.
2008-01-01
As the main difference between bacterial and mammalian cell membranes is their net charge, the focal point of consideration in many model membrane experiments with antimicrobial peptides is lipid headgroup charge. We studied the interaction of the human multifunctional peptide LL-37 with single phospholipid monolayers, bilayers, and bilayers composed of binary mixtures of the four phospholipid species predominantly used in model membrane experiments (phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylserine). We found that 1), the effects on single lipid monolayers are not comparable to those on the corresponding bilayers; 2), there are four different effects of LL-37 on bilayers of the four lipids; 3), the preference of LL-37 for the specific lipids is roughly inversely related to chain packing density; and 4), in the binary lipid mixtures, one lipid—and not necessarily the charged one—generally governs the mode of lipid/peptide interaction. Thus, our results show that lipid net charge is not the decisive factor determining the membrane-perturbing mechanism of LL-37, but only one of several parameters, among them packing density, the ability to form intermolecular H-bonds, and lipid molecular shape, which emphasizes how profoundly the choice of the model system can influence the outcome of a study of lipid/peptide interaction. PMID:18326643
Sonic hedgehog controls enteric nervous system development by patterning the extracellular matrix.
Nagy, Nandor; Barad, Csilla; Graham, Hannah K; Hotta, Ryo; Cheng, Lily S; Fejszak, Nora; Goldstein, Allan M
2016-01-15
The enteric nervous system (ENS) develops from neural crest cells that migrate along the intestine, differentiate into neurons and glia, and pattern into two plexuses within the gut wall. Inductive interactions between epithelium and mesenchyme regulate gut development, but the influence of these interactions on ENS development is unknown. Epithelial-mesenchymal recombinations were constructed using avian hindgut mesenchyme and non-intestinal epithelium from the bursa of Fabricius. These recombinations led to abnormally large and ectopically positioned ganglia. We hypothesized that sonic hedgehog (Shh), a secreted intestinal epithelial protein not expressed in the bursa, mediates this effect. Inhibition of Shh signaling, by addition of cyclopamine or a function-blocking antibody, resulted in large, ectopic ganglia adjacent to the epithelium. Shh overexpression, achieved in ovo using Shh-encoding retrovirus and in organ culture using recombinant protein, led to intestinal aganglionosis. Shh strongly induced the expression of versican and collagen type IX, whereas cyclopamine reduced expression of these chondroitin sulfate proteoglycans that are known to be inhibitory to neural crest cell migration. Shh also inhibited enteric neural crest-derived cell (ENCC) proliferation, promoted neuronal differentiation, and reduced expression of Gdnf, a key regulator of ENS formation. Ptc1 and Ptc2 were not expressed by ENCCs, and migration of isolated ENCCs was not inhibited by Shh protein. These results suggest that epithelial-derived Shh acts indirectly on the developing ENS by regulating the composition of the intestinal microenvironment.
Schor; O'Carroll
2000-08-01
We obtain different properties of general d dimensional lattice ferromagnetic spin systems with nearest neighbor interactions in the high temperature region (beta<1). Each model is characterized by a single site a priori spin distribution, taken to be even. We state our results in terms of the parameter alpha=-3(2) where denotes the kth moment of the a priori distribution. Associated with the model is a lattice quantum field theory that is known to contain particles. We show that for alpha>0, beta small, there exists a bound state with mass below the two-particle threshold. For alpha<0, bound states do not exist. The existence of the bound state has implications on the decay of correlations, i.e., the four-point function decays at a slower rate than twice that of the two-point function. These results are obtained using a lattice version of the Bethe-Salpeter equation in the ladder approximation. The existence and nonexistence results generalize to N-component models with rotationally invariant a priori spin distributions.
Planar Gradient Diffusion System to Investigate Chemotaxis in a 3D Collagen Matrix.
Stout, David A; Toyjanova, Jennet; Franck, Christian
2015-06-12
The importance of cell migration can be seen through the development of human life. When cells migrate, they generate forces and transfer these forces to their surrounding area, leading to cell movement and migration. In order to understand the mechanisms that can alter and/or affect cell migration, one can study these forces. In theory, understanding the fundamental mechanisms and forces underlying cell migration holds the promise of effective approaches for treating diseases and promoting cellular transplantation. Unfortunately, modern chemotaxis chambers that have been developed are usually restricted to two dimensions (2D) and have complex diffusion gradients that make the experiment difficult to interpret. To this end, we have developed, and describe in this paper, a direct-viewing chamber for chemotaxis studies, which allows one to overcome modern chemotaxis chamber obstacles able to measure cell forces and specific concentration within the chamber in a 3D environment to study cell 3D migration. More compelling, this approach allows one to successfully model diffusion through 3D collagen matrices and calculate the coefficient of diffusion of a chemoattractant through multiple different concentrations of collagen, while keeping the system simple and user friendly for traction force microscopy (TFM) and digital volume correlation (DVC) analysis.
Happonen, Kaisa E; Heinegård, Dick; Saxne, Tore; Blom, Anna M
2012-11-01
Rheumatoid arthritis (RA) is a highly disabling disease affecting all structures of the joint. Understanding the pathology behind the development of RA is essential for developing targeted therapeutic strategies as well as for developing novel markers to predict disease onset. Several molecules normally hidden within the cartilage tissue are exposed to complement components in the synovial fluid upon cartilage breakdown. Some of these have been shown to activate complement and toll-like receptors, which may enhance an already existing inflammatory response, thereby worsening the course of disease. Other cartilage-resident molecules have in contrast shown to possess complement-inhibitory properties. Knowledge about mechanisms behind pathological complement activation in the joints will hopefully lead to methods which allow us to distinguish patients with pathological complement activation from those where other inflammatory pathways are predominant. This will help to elucidate which patients will benefit from complement inhibitory therapies, which are thought to aid a specific subset of patients or patients at a certain stage of disease. Future challenges are to target the complement inhibition specifically to the joints to minimize systemic complement blockade.
NASA Technical Reports Server (NTRS)
Glass, David E.
2008-01-01
Thermal protection systems (TPS) and hot structures are required for a range of hypersonic vehicles ranging from ballistic reentry to hypersonic cruise vehicles, both within Earth's atmosphere and non-Earth atmospheres. The focus of this paper is on air breathing hypersonic vehicles in the Earth's atmosphere. This includes single-stage to orbit (SSTO), two-stage to orbit (TSTO) accelerators, access to space vehicles, and hypersonic cruise vehicles. This paper will start out with a brief discussion of aerodynamic heating and thermal management techniques to address the high heating, followed by an overview of TPS for rocket-launched and air-breathing vehicles. The argument is presented that as we move from rocket-based vehicles to air-breathing vehicles, we need to move away from the insulated airplane approach used on the Space Shuttle Orbiter to a wide range of TPS and hot structure approaches. The primary portion of the paper will discuss issues and design options for CMC TPS and hot structure components, including leading edges, acreage TPS, and control surfaces. The current state-of-the-art will be briefly discussed for some of the components. The two primary technical challenges impacting the use of CMC TPS and hot structures for hypersonic vehicles are environmental durability and fabrication, and will be discussed briefly.
Sonic hedgehog controls enteric nervous system development by patterning the extracellular matrix
Nagy, Nandor; Barad, Csilla; Graham, Hannah K.; Hotta, Ryo; Cheng, Lily S.; Fejszak, Nora; Goldstein, Allan M.
2016-01-01
The enteric nervous system (ENS) develops from neural crest cells that migrate along the intestine, differentiate into neurons and glia, and pattern into two plexuses within the gut wall. Inductive interactions between epithelium and mesenchyme regulate gut development, but the influence of these interactions on ENS development is unknown. Epithelial-mesenchymal recombinations were constructed using avian hindgut mesenchyme and non-intestinal epithelium from the bursa of Fabricius. These recombinations led to abnormally large and ectopically positioned ganglia. We hypothesized that sonic hedgehog (Shh), a secreted intestinal epithelial protein not expressed in the bursa, mediates this effect. Inhibition of Shh signaling, by addition of cyclopamine or a function-blocking antibody, resulted in large, ectopic ganglia adjacent to the epithelium. Shh overexpression, achieved in ovo using Shh-encoding retrovirus and in organ culture using recombinant protein, led to intestinal aganglionosis. Shh strongly induced the expression of versican and collagen type IX, whereas cyclopamine reduced expression of these chondroitin sulfate proteoglycans that are known to be inhibitory to neural crest cell migration. Shh also inhibited enteric neural crest-derived cell (ENCC) proliferation, promoted neuronal differentiation, and reduced expression of Gdnf, a key regulator of ENS formation. Ptc1 and Ptc2 were not expressed by ENCCs, and migration of isolated ENCCs was not inhibited by Shh protein. These results suggest that epithelial-derived Shh acts indirectly on the developing ENS by regulating the composition of the intestinal microenvironment. PMID:26674309
NASA Astrophysics Data System (ADS)
Craps, Ben; Evnin, Oleg; Nguyen, Kévin
2017-02-01
Matrix quantum mechanics offers an attractive environment for discussing gravitational holography, in which both sides of the holographic duality are well-defined. Similarly to higher-dimensional implementations of holography, collapsing shell solutions in the gravitational bulk correspond in this setting to thermalization processes in the dual quantum mechanical theory. We construct an explicit, fully nonlinear supergravity solution describing a generic collapsing dilaton shell, specify the holographic renormalization prescriptions necessary for computing the relevant boundary observables, and apply them to evaluating thermalizing two-point correlation functions in the dual matrix theory.
NASA Astrophysics Data System (ADS)
Jacobs, Verne; Kutana, Alex
The frequency-dependent transition rates for single-photon and multi-photon processes in quantized many-electron systems are evaluated using a reduced-density-matrix approach. We provide a fundamental quantum-mechanical foundation for systematic spectral simulations. A perturbation expansion of the frequency-domain Liouville-space self-energy operator is introduced for detailed evaluations of the spectral-line shapes. In the diagonal-resolvent (isolated-line) and short-memory-time (Markov) approximations, the lowest-order contributions to the spectral-line widths and shifts associated with environmental electron-photon and electron-phonon interactions are systematically evaluated. Our description is directly applicable to electromagnetic processes in a wide variety of many-electron systems, without premature approximations. In particular, our approach can be applied to investigate quantum optical phenomena involving electrons in both bulk and nanoscale semiconductor materials entirely from first principles, using a single-electron basis set obtained from density functional theory as a starting point for a many-electron description. Work supported by the Office of Naval Research through the Basic Research Program at The Naval Research Laboratory. A portion of this work was performed under the ASEE post doc program at NRL.
Othman, Faridah; Taghieh, Mahmood
2016-01-01
Optimal operation of water resources in multiple and multipurpose reservoirs is very complicated. This is because of the number of dams, each dam’s location (Series and parallel), conflict in objectives and the stochastic nature of the inflow of water in the system. In this paper, performance optimization of the system of Karun and Dez reservoir dams have been studied and investigated with the purposes of hydroelectric energy generation and providing water demand in 6 dams. On the Karun River, 5 dams have been built in the series arrangements, and the Dez dam has been built parallel to those 5 dams. One of the main achievements in this research is the implementation of the structure of production of hydroelectric energy as a function of matrix in MATLAB software. The results show that the role of objective function structure for generating hydroelectric energy in weighting method algorithm is more important than water supply. Nonetheless by implementing ε- constraint method algorithm, we can both increase hydroelectric power generation and supply around 85% of agricultural and industrial demands. PMID:27248152
Heydari, Mohammad; Othman, Faridah; Taghieh, Mahmood
2016-01-01
Optimal operation of water resources in multiple and multipurpose reservoirs is very complicated. This is because of the number of dams, each dam's location (Series and parallel), conflict in objectives and the stochastic nature of the inflow of water in the system. In this paper, performance optimization of the system of Karun and Dez reservoir dams have been studied and investigated with the purposes of hydroelectric energy generation and providing water demand in 6 dams. On the Karun River, 5 dams have been built in the series arrangements, and the Dez dam has been built parallel to those 5 dams. One of the main achievements in this research is the implementation of the structure of production of hydroelectric energy as a function of matrix in MATLAB software. The results show that the role of objective function structure for generating hydroelectric energy in weighting method algorithm is more important than water supply. Nonetheless by implementing ε- constraint method algorithm, we can both increase hydroelectric power generation and supply around 85% of agricultural and industrial demands.
NASA Astrophysics Data System (ADS)
Tarhan, Başak; Ünlü, Kahraman
2005-11-01
Designing environmentally safe and economically feasible landfills can be a challenging task due to complex interactions that need to be taken into account between landfill size, waste and site characteristics. The main focus of this study is, by interfacing the geographic information systems (GIS) with system simulation models (SSM), to develop a methodology and a landfill design component selection matrix that can enable the determination of landfill design components providing the desired performance with minimal design details. In this paper, the conceptual framework and applications of the developed methodology demonstrating the selection of landfill design components that are suitable for the existing site conditions are presented. The conceptual model defines design variables, performance criteria and design components of a landfill. GIS and SSM are used to handle the site-specific data and to evaluate the landfill performance, respectively. Results indicate that the landfills having the same design characteristics show different performance under different site conditions; therefore, a landfill design that is technically and economically feasible should be selected on the basis of performance.
Hornišová, K; Billik, P
2014-01-01
Traditional technique of horn equation solved by transfer matrices as a model of vibration of ultrasonic systems consisting of sectional transducer, horn and load is discussed. Expression of vibration modes as a ratio of solutions of two Schrödinger equations gives better insight to the structure of a transfer matrix and properties of amplitudes of displacement and strain, and enables more systematic search for analytic solutions. Incorrectness of impedance matrix method and of equivalent circuit method on one hand and correctness and advantages of transfer matrix method in avoiding numerical artifacts and revealing the real features of the model on the other hand are demonstrated on examples. Discontinuous dependence of the nth resonant value on parameters of ultrasonic system, recently described in Sturm-Liouville theory, and consequently, a jump from half-wave to full-wave mode, is observed in a transducer model.
NASA Astrophysics Data System (ADS)
Godin, T. J.; Haydock, Roger
1991-04-01
The Block Recursion Library, a collection of FORTRAN subroutines, calculates submatrices of the resolvent of a linear operator. The resolvent, in matrix theory, is a powerful tool for extracting information about solutions of linear systems. The routines use the block recursion method and achieve high accuracy for very large systems of coupled equations. This technique is a generalization of the scalar recursion method, an accurate technique for finding the local density of states. A sample program uses these routines to find the quantum mechanical transmittance of a randomly disordered two-dimensional cluster of atoms.