Science.gov

Sample records for precise structure analysis

  1. Analysis and Test Support for Phillips Laboratory Precision Structures

    DTIC Science & Technology

    1998-11-01

    Air Force Research Laboratory ( AFRL ), Phillips Research Site . Task objectives centered...around analysis and structural dynamic test support on experiments within the Space Vehicles Directorate at Kirtland Air Force Base. These efforts help...support for Phillips Laboratory Precision Structures." Mr. James Goodding of CSA Engineering was the principal investigator for this task. Mr.

  2. Concepts, analysis and development for precision deployable space structures

    NASA Technical Reports Server (NTRS)

    Miller, Richard K.; Thomson, Mark; Hedgepeth, John M.

    1991-01-01

    Several issues surrounding the development of large Precision Segmented Reflector (PSR) designs are investigated. The concerns include nonlinear dynamics of large unruly masses such as the multi-layer thermal insulation of sunshades for instruments such as the precision pointing 20-m-diameter Large Deployable Reflector (LDR). A study of the residual oscillations after bang-bang reorientation maneuvers of a rigid satellite with a string appendage is presented. Application is made to the design of a sunshade (thermal blanket) for the LDE satellite. Another concern is the development of a deployable truss that has minimum structural redundancy (such as the tetrahedral truss) and that can be configured with planar and doubly curved geometries. A kinematically synchronized articulation scheme for a deployable tetrahedral truss is presented. Called the Tetrapac, this truss is currently limited to a planar configuration that has two rings. The final concern is the development and demonstration of hardware that enables astronauts to attach large, cumbersome, and fragile precision reflector segments to an erectable truss structure. This task must be accomplished with a high degree of precision and with relative ease. A design for a Panel Attachment Device (PAD) was developed and manufactured for neutral buoyancy simulations to be performed by LaRC.

  3. Precision antenna reflector structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1985-01-01

    The assembly of the Large Precise Reflector Infrared Telescope is detailed. Also given are the specifications for the Aft Cargo Carrier and the Large Precision Reflector structure. Packaging concepts and options, stowage depth and support truss geometry are also considered. An example of a construction scenario is given.

  4. Development of High Precision Tsunami Runup Calculation Method Coupled with Structure Analysis

    NASA Astrophysics Data System (ADS)

    Arikawa, Taro; Seki, Katsumi; Chida, Yu; Takagawa, Tomohiro; Shimosako, Kenichiro

    2017-04-01

    The 2011 Great East Japan Earthquake (GEJE) has shown that tsunami disasters are not limited to inundation damage in a specified region, but may destroy a wide area, causing a major disaster. Evaluating standing land structures and damage to them requires highly precise evaluation of three-dimensional fluid motion - an expensive process. Our research goals were thus to develop a coupling STOC-CADMAS (Arikawa and Tomita, 2016) coupling with the structure analysis (Arikawa et. al., 2009) to efficiently calculate all stages from tsunami source to runup including the deformation of structures and to verify their applicability. We also investigated the stability of breakwaters at Kamaishi Bay. Fig. 1 shows the whole of this calculation system. The STOC-ML simulator approximates pressure by hydrostatic pressure and calculates the wave profiles based on an equation of continuity, thereby lowering calculation cost, primarily calculating from a e epi center to the shallow region. As a simulator, STOC-IC solves pressure based on a Poisson equation to account for a shallower, more complex topography, but reduces computation cost slightly to calculate the area near a port by setting the water surface based on an equation of continuity. CS3D also solves a Navier-Stokes equation and sets the water surface by VOF to deal with the runup area, with its complex surfaces of overflows and bores. STR solves the structure analysis including the geo analysis based on the Biot's formula. By coupling these, it efficiently calculates the tsunami profile from the propagation to the inundation. The numerical results compared with the physical experiments done by Arikawa et. al.,2012. It was good agreement with the experimental ones. Finally, the system applied to the local situation at Kamaishi bay. The almost breakwaters were washed away, whose situation was similar to the damage at Kamaishi bay. REFERENCES T. Arikawa and T. Tomita (2016): "Development of High Precision Tsunami Runup

  5. A combined acetylcholinesterase and immunohistochemical method for precise anatomical analysis of intrinsic cardiac neural structures.

    PubMed

    Pauza, Dainius H; Rysevaite-Kyguoliene, Kristina; Vismantaite, Jurgita; Brack, Kieran E; Inokaitis, Hermanas; Pauza, Audrys G; Rimasauskaite-Petraitienė, Viktorija; Pauzaite, Jaune I; Pauziene, Neringa

    2014-12-01

    A significant challenge when investigating autonomic neuroanatomy is being able to reliably obtain tissue that contains neuronal structures of interest. Currently, histochemical staining for acetylcholinesterase (AChE) remains the most feasible and reliable method to visualize intrinsic nerves and ganglia in whole organs. In order to precisely visualize and sample intrinsic cardiac nerves and ganglia for subsequent immunofluorescent labeling, we developed a modified histochemical AChE method using material from pig and sheep hearts. The method involves: (1) chemical prefixation of the whole heart, (2) short-term and weak histochemical staining for AChE in situ, (3) visual examination and extirpation of the stained neural structures from the whole heart, (4) freezing, embedding and cryostat sectioning of the tissue of interest, and (5) immunofluorescent labeling and microscopic analysis of neural structures. Firstly, our data demonstrate that this modified AChE protocol labeled intrinsic cardiac nerves as convincingly as our previously published data. Secondly, there was the added advantage that adrenergic, cholinergic and peptidergic neuropeptides, namely protein gene product 9.5 (PGP 9.5), neurofilament (NF), tyrosine hydroxylase (TH), vesicular monoamine transporter (VMAT2), neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), calcitonin gene related peptide (CGRP), and substance P may be identified. Our method allows the precise sampling of neural structures including autonomic ganglia, intrinsic nerves and bundles of nerve fibers and even single neurons from the whole heart. This method saves time, effort and a substantial amount of antisera. Nonetheless, the proof of specific staining for many other autonomic neuronal markers has to be provided in subsequent studies.

  6. Local crystal structure analysis with several picometer precision using scanning transmission electron microscopy.

    PubMed

    Kimoto, Koji; Asaka, Toru; Yu, Xiuzhen; Nagai, Takuro; Matsui, Yoshio; Ishizuka, Kazuo

    2010-06-01

    We report a local crystal structure analysis with a high precision of several picometers on the basis of scanning transmission electron microscopy (STEM). Advanced annular dark-field (ADF) imaging has been demonstrated using software-based experimental and data-processing techniques, such as the improvement of signal-to-noise ratio, the reduction of image distortion, the quantification of experimental parameters (e.g., thickness and defocus) and the resolution enhancement by maximum-entropy deconvolution. The accuracy in the atom position measurement depends on the validity of the incoherent imaging approximation, in which an ADF image is described as the convolution between the incident probe profile and scattering objects. Although the qualitative interpretation of ADF image contrast is possible for a wide range of specimen thicknesses, the direct observation of a crystal structure with deep-sub-angstrom accuracy requires a thin specimen (e.g., 10nm), as well as observation of the structure image by conventional high-resolution transmission electron microscopy. Copyright 2009 Elsevier B.V. All rights reserved.

  7. Concepts and analysis for precision segmented reflector and feed support structures

    NASA Technical Reports Server (NTRS)

    Miller, Richard K.; Thomson, Mark W.; Hedgepeth, John M.

    1990-01-01

    Several issues surrounding the design of a large (20-meter diameter) Precision Segmented Reflector are investigated. The concerns include development of a reflector support truss geometry that will permit deployment into the required doubly-curved shape without significant member strains. For deployable and erectable reflector support trusses, the reduction of structural redundancy was analyzed to achieve reduced weight and complexity for the designs. The stiffness and accuracy of such reduced member trusses, however, were found to be affected to a degree that is unexpected. The Precision Segmented Reflector designs were developed with performance requirements that represent the Reflector application. A novel deployable sunshade concept was developed, and a detailed parametric study of various feed support structural concepts was performed. The results of the detailed study reveal what may be the most desirable feed support structure geometry for Precision Segmented Reflector/Large Deployable Reflector applications.

  8. Structural Analysis and Testing of an Erectable Truss for Precision Segmented Reflector Application

    NASA Technical Reports Server (NTRS)

    Collins, Timothy J.; Fichter, W. B.; Adams, Richard R.; Javeed, Mehzad

    1995-01-01

    This paper describes analysis and test results obtained at Langley Research Center (LaRC) on a doubly curved testbed support truss for precision reflector applications. Descriptions of test procedures and experimental results that expand upon previous investigations are presented. A brief description of the truss is given, and finite-element-analysis models are described. Static-load and vibration test procedures are discussed, and experimental results are shown to be repeatable and in generally good agreement with linear finite-element predictions. Truss structural performance (as determined by static deflection and vibration testing) is shown to be predictable and very close to linear. Vibration test results presented herein confirm that an anomalous mode observed during initial testing was due to the flexibility of the truss support system. Photogrammetric surveys with two 131-in. reference scales show that the root-mean-square (rms) truss-surface accuracy is about 0.0025 in. Photogrammetric measurements also indicate that the truss coefficient of thermal expansion (CTE) is in good agreement with that predicted by analysis. A detailed description of the photogrammetric procedures is included as an appendix.

  9. Development of High Precision Tsunami Runup Calculation Method Coupled with Structure Analysis

    NASA Astrophysics Data System (ADS)

    Arikawa, T.

    2016-12-01

    The 2011 Great East Japan Earthquake (GEJE) has shown that tsunami disasters are not limited to inundation damage in a specified region, but may destroy a wide area, causing a major disaster. Evaluating standing land structures and damage to them requires highly precise evaluation of three-dimensional fluid motion - an expensive process. Our research goals were thus to develop a coupling STOC-CADMAS (Arikawa and Tomita, 2016) coupling with the structure analysis (Arikawa et. al., 2009) to efficiently calculate all stages from tsunami source to runup including the deformation of structures and to verify their applicability. We also investigated the stability of breakwaters at Kamaishi Bay. Fig. 1 shows the whole of this calculation system. The STOC-ML simulator approximates pressure by hydrostatic pressure and calculates the wave profiles based on an equation of continuity, thereby lowering calculation cost, primarily calculating from a e epi center to the shallow region. As a simulator, STOC-IC solves pressure based on a Poisson equation to account for a shallower, more complex topography, but reduces computation cost slightly to calculate the area near a port by setting the water surface based on an equation of continuity. CS3D also solves a Navier-Stokes equation and sets the water surface by VOF to deal with the runup area, with its complex surfaces of overflows and bores. STR solves the structure analysis including the geo analysis based on the Biot's formula. By coupling these, it efficiently calculates the tsunami profile from the propagation to the inundation. The numerical results compared with the physical experiments done by Arikawa et. al.,2012. It was good agreement with the experimental ones. Finally, the system applied to the local situation at Kamaishi bay. The almost breakwaters were washed away, whose situation was similar to the damage at Kamaishi bay. ACKNOWLEDGEMENTSThis work was supported by Council for Science, Technology and Innovation (CSTI

  10. Precision space structures

    NASA Astrophysics Data System (ADS)

    Soosaar, K.

    1985-04-01

    NASA large space structures efforts to date aimed towards large, flexible antenna-like structures (30-100M) with relatively long wavelengths (1-30cm) and moderate disturbances leading to some structure-control interaction. Potential missions in the OPTICS regime require small reflectors/mirrors, short wavelengths (visible to 100 microns), very tight tolerances in surface, alignment, pointing stability, as well as the potential of considerable on-board disturbances. For optics systems: figure/surface control can be quasi-static, active/passive isolation schemes are possible, vibration control is necessary, and the attitude control system can be low BW - Ground testing of reflectors and mirrors is more feasible than with antennas.

  11. Precision Composite Space Structures

    DTIC Science & Technology

    2007-10-15

    243-246. [D.128]. Kaddour AS, Soden PD, Hinton MJ. Failure of ± 55 degree filament wound glass/epoxy composite tubes under biaxial compression. J...Corporation. The T-joint was modified to include an adhesively bonded sheet of titanium foil that would induce measurable distortions of the...properties. Most all of these were found to be directed at progressive failure analysis and lacked the fidelity needed to be useful for dimensional

  12. Precision Efficacy Analysis for Regression.

    ERIC Educational Resources Information Center

    Brooks, Gordon P.

    When multiple linear regression is used to develop a prediction model, sample size must be large enough to ensure stable coefficients. If the derivation sample size is inadequate, the model may not predict well for future subjects. The precision efficacy analysis for regression (PEAR) method uses a cross- validity approach to select sample sizes…

  13. Adaptive structures to enable ground test validation of precision structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James F.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The use of analytical models and ground-based experimental validation of precision space structures is addressed. The application of adaptive structures to such validation of precision space structures is addressed, with the focus on adaptive truss structures.

  14. Structural design of active precision structures

    NASA Astrophysics Data System (ADS)

    Charon, W.

    The independent structural design for stochastically disturbed active structures, as part of the integrated structure/control design methodology, is the subject of this paper. The methodology requires the consideration of a generic controller in order to guarantee the performances of the active structure resulting from the mechanical design. An elastic 20 m long Extendable and Retractable Mast fitted with piezoelectric local actuators and an offset rigid antenna illustrates the method. Configurations, values of modal dampings are investigated using modal analysis, analysis of disturbance and actuator effects, inclusion of modal shapes, choice of actuators and sensors, determination of final performances.

  15. Joint Estimation of Multiple Precision Matrices with Common Structures

    PubMed Central

    Lee, Wonyul; Liu, Yufeng

    2015-01-01

    Estimation of inverse covariance matrices, known as precision matrices, is important in various areas of statistical analysis. In this article, we consider estimation of multiple precision matrices sharing some common structures. In this setting, estimating each precision matrix separately can be suboptimal as it ignores potential common structures. This article proposes a new approach to parameterize each precision matrix as a sum of common and unique components and estimate multiple precision matrices in a constrained l1 minimization framework. We establish both estimation and selection consistency of the proposed estimator in the high dimensional setting. The proposed estimator achieves a faster convergence rate for the common structure in certain cases. Our numerical examples demonstrate that our new estimator can perform better than several existing methods in terms of the entropy loss and Frobenius loss. An application to a glioblastoma cancer data set reveals some interesting gene networks across multiple cancer subtypes. PMID:26568704

  16. High Precision Thermal, Structural and Optical Analysis of an External Occulter Using a Common Model and the General Purpose Multi-Physics Analysis Tool Cielo

    NASA Technical Reports Server (NTRS)

    Hoff, Claus; Cady, Eric; Chainyk, Mike; Kissil, Andrew; Levine, Marie; Moore, Greg

    2011-01-01

    The efficient simulation of multidisciplinary thermo-opto-mechanical effects in precision deployable systems has for years been limited by numerical toolsets that do not necessarily share the same finite element basis, level of mesh discretization, data formats, or compute platforms. Cielo, a general purpose integrated modeling tool funded by the Jet Propulsion Laboratory and the Exoplanet Exploration Program, addresses shortcomings in the current state of the art via features that enable the use of a single, common model for thermal, structural and optical aberration analysis, producing results of greater accuracy, without the need for results interpolation or mapping. This paper will highlight some of these advances, and will demonstrate them within the context of detailed external occulter analyses, focusing on in-plane deformations of the petal edges for both steady-state and transient conditions, with subsequent optical performance metrics including intensity distributions at the pupil and image plane.

  17. High Precision Thermal, Structural and Optical Analysis of an External Occulter Using a Common Model and the General Purpose Multi-Physics Analysis Tool Cielo

    NASA Technical Reports Server (NTRS)

    Hoff, Claus; Cady, Eric; Chainyk, Mike; Kissil, Andrew; Levine, Marie; Moore, Greg

    2011-01-01

    The efficient simulation of multidisciplinary thermo-opto-mechanical effects in precision deployable systems has for years been limited by numerical toolsets that do not necessarily share the same finite element basis, level of mesh discretization, data formats, or compute platforms. Cielo, a general purpose integrated modeling tool funded by the Jet Propulsion Laboratory and the Exoplanet Exploration Program, addresses shortcomings in the current state of the art via features that enable the use of a single, common model for thermal, structural and optical aberration analysis, producing results of greater accuracy, without the need for results interpolation or mapping. This paper will highlight some of these advances, and will demonstrate them within the context of detailed external occulter analyses, focusing on in-plane deformations of the petal edges for both steady-state and transient conditions, with subsequent optical performance metrics including intensity distributions at the pupil and image plane.

  18. Precise thermal NDE for quantifying structural damage

    SciTech Connect

    Del Grande, N.K.; Durbin, P.F.

    1995-09-18

    The authors demonstrated a fast, wide-area, precise thermal NDE imaging system to quantify aircraft corrosion damage, such as percent metal loss, above a threshold of 5% with 3% overall uncertainties. The DBIR precise thermal imaging and detection method has been used successfully to characterize defect types, and their respective depths, in aircraft skins, and multi-layered composite materials used for wing patches, doublers and stiffeners. This precise thermal NDE inspection tool has long-term potential benefits to evaluate the structural integrity of airframes, pipelines and waste containers. They proved the feasibility of the DBIR thermal NDE imaging system to inspect concrete and asphalt-concrete bridge decks. As a logical extension to the successful feasibility study, they plan to inspect a concrete bridge deck from a moving vehicle to quantify the volumetric damage within the deck and the percent of the deck which has subsurface delaminations. Potential near-term benefits are in-service monitoring from a moving vehicle to inspect the structural integrity of the bridge deck. This would help prioritize the repair schedule for a reported 200,000 bridge decks in the US which need substantive repairs. Potential long-term benefits are affordable, and reliable, rehabilitation for bridge decks.

  19. Pactruss support structure for precision segmented reflectors

    NASA Technical Reports Server (NTRS)

    Hedgepeth, John M.

    1989-01-01

    The application of the Pactruss deployable structure to the support of large paraboloidal reflectors of very high precision was studied. The Pactruss concept, originally conceived for the Space Station truss, is shown to be suitable for use in a triangular arrangement to support a reflector surface composed of hexagonal reflector panels. A hybrid of Pactruss structural and deployable single-fold beams is shown to accommodate a center body. A minor alteration in the geometry is in order to avoid lockup during deployment. To assess the capability of the hybrid Pactruss structure, an example truss supporting a full-scale (20 meter diameter) infrared telescope was analyzed for static and dynamic performance. A truss structure weighing 800 kilograms gave adequate support to a reflector surface weighing 3,000 kilograms.

  20. Structurally uniform and atomically precise carbon nanostructures

    NASA Astrophysics Data System (ADS)

    Segawa, Yasutomo; Ito, Hideto; Itami, Kenichiro

    2016-01-01

    Nanometre-sized carbon materials consisting of benzene units oriented in unique geometric patterns, hereafter named nanocarbons, conduct electricity, absorb and emit light, and exhibit interesting magnetic properties. Spherical fullerene C60, cylindrical carbon nanotubes and sheet-like graphene are representative forms of nanocarbons, and theoretical simulations have predicted several exotic 3D nanocarbon structures. At present, synthetic routes to nanocarbons mainly lead to mixtures of molecules with a range of different structures and properties, which cannot be easily separated or refined into pure forms. Some researchers believe that it is impossible to synthesize these materials in a precise manner. Obtaining ‘pure’ nanocarbons is a great challenge in the field of nanocarbon science, and the construction of structurally uniform nanocarbons, ideally as single molecules, is crucial for the development of functional materials in nanotechnology, electronics, optics and biomedical applications. This Review highlights the organic chemistry approach — more specifically, bottom-up construction with atomic precision — that is currently the most promising strategy towards this end.

  1. Precision Machining Technologies. Occupational Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Occupational Competency Analysis Profile (OCAP), which is one of a series of OCAPs developed to identify the skills that Ohio employers deem necessary to entering a given occupation/occupational area, lists the occupational, academic, and employability skills required of individuals entering the occupation of precision machinist. The…

  2. High Precision Prediction of Functional Sites in Protein Structures

    PubMed Central

    Buturovic, Ljubomir; Wong, Mike; Tang, Grace W.; Altman, Russ B.; Petkovic, Dragutin

    2014-01-01

    We address the problem of assigning biological function to solved protein structures. Computational tools play a critical role in identifying potential active sites and informing screening decisions for further lab analysis. A critical parameter in the practical application of computational methods is the precision, or positive predictive value. Precision measures the level of confidence the user should have in a particular computed functional assignment. Low precision annotations lead to futile laboratory investigations and waste scarce research resources. In this paper we describe an advanced version of the protein function annotation system FEATURE, which achieved 99% precision and average recall of 95% across 20 representative functional sites. The system uses a Support Vector Machine classifier operating on the microenvironment of physicochemical features around an amino acid. We also compared performance of our method with state-of-the-art sequence-level annotator Pfam in terms of precision, recall and localization. To our knowledge, no other functional site annotator has been rigorously evaluated against these key criteria. The software and predictive models are incorporated into the WebFEATURE service at http://feature.stanford.edu/wf4.0-beta. PMID:24632601

  3. Advanced structural design for precision radial velocity instruments

    NASA Astrophysics Data System (ADS)

    Baldwin, Dan; Szentgyorgyi, Andrew; Barnes, Stuart; Bean, Jacob; Ben-Ami, Sagi; Brennan, Patricia; Budynkiewicz, Jamie; Chun, Moo-Young; Conroy, Charlie; Crane, Jeffrey D.; Epps, Harland; Evans, Ian; Evans, Janet; Foster, Jeff; Frebel, Anna; Gauron, Thomas; Guzman, Dani; Hare, Tyson; Jang, Bi-Ho; Jang, Jeong-Gyun; Jordan, Andres; Kim, Jihun; Kim, Kang-Min; Mendes de Oliveira, Claudia; Lopez-Morales, Mercedes; McCracken, Kenneth; McMuldroch, Stuart; Miller, Joseph; Mueller, Mark; Oh, Jae Sok; Ordway, Mark; Park, Byeong-Gon; Park, Chan; Park, Sung-Joon; Paxson, Charles; Phillips, David; Plummer, David; Podgorski, William; Seifahrt, Andreas; Stark, Daniel; Steiner, Joao; Uomoto, Alan; Walsworth, Ronald; Yu, Young-Sam

    2016-07-01

    The GMT-Consortium Large Earth Finder (G-CLEF) is an echelle spectrograph with precision radial velocity (PRV) capability that will be a first light instrument for the Giant Magellan Telescope (GMT). G-CLEF has a PRV precision goal of 40 cm/sec (10 cm/s for multiple measurements) to enable detection of Earth-like exoplanets in the habitable zones of sun-like stars1. This precision is a primary driver of G-CLEF's structural design. Extreme stability is necessary to minimize image motions at the CCD detectors. Minute changes in temperature, pressure, and acceleration environments cause structural deformations, inducing image motions which degrade PRV precision. The instrument's structural design will ensure that the PRV goal is achieved under the environments G-CLEF will be subjected to as installed on the GMT azimuth platform, including: Millikelvin (0.001 °K) thermal soaks and gradients 10 millibar changes in ambient pressure Changes in acceleration due to instrument tip/tilt and telescope slewing Carbon fiber/cyanate composite was selected for the optical bench structure in order to meet performance goals. Low coefficient of thermal expansion (CTE) and high stiffness-to-weight are key features of the composite optical bench design. Manufacturability and serviceability of the instrument are also drivers of the design. In this paper, we discuss analyses leading to technical choices made to minimize G-CLEF's sensitivity to changing environments. Finite element analysis (FEA) and image motion sensitivity studies were conducted to determine PRV performance under operational environments. We discuss the design of the optical bench structure to optimize stiffness-to-weight and minimize deformations due to inertial and pressure effects. We also discuss quasi-kinematic mounting of optical elements and assemblies, and optimization of these to ensure minimal image motion under thermal, pressure, and inertial loads expected during PRV observations.

  4. Precision truss structures from concept to hardware reality: application to the Micro-Precision Interferometer Testbed

    NASA Astrophysics Data System (ADS)

    Sword, Lee F.; Carne, Thomas G.

    1993-09-01

    This paper describes the development of the truss structure at the Jet Propulsion Laboratory that forms the backbone of JPL's Micro-Precision Interferometer (MPI) Testbed. The Micro- Precision Interferometer (MPI) Testbed is the third generation of Control Structure Interaction (CSI) Testbeds constructed by JPL aimed at developing and validating control concepts. The MPI testbed is essentially a space-based Michelson interferometer suspended in a ground- based laboratory. This instrument, mounted to the flexible truss, requires nanometer level precision alignment and positioning of its optical elements to achieve science objectives. A layered control architecture, utilizing isolation, structural control, and active optical control technologies, allow the system to meet its vibration attenuation goals. Success of the structural control design, which involves replacement of truss struts with active and/or passive elements, depends heavily on high fidelity models of the structure to evaluate strut placement locations. The first step in obtaining an accurate structure model is to build a structure which is linear.

  5. Precise documentation of well-structured programs

    SciTech Connect

    Parnas, D.L.; Madey, J.; Iglewski, M.

    1997-11-01

    This paper describes a new form of program documentation that is precise, systematic and readable. This documentation comprises a set of displays supplemented by a lexicon and an index. Each display presents a program fragment in such a way that its correctness can be examined without looking at any other display. Each display has three parts: (1) the specification of the program presented in the display, (2) the program itself, and (3) the specifications of programs invoked by this program. The displays are intended to be used by Software Engineers as a reference document during inspection and maintenance. This paper also introduces a specification technique that is a refinement of Mills functional approach to program documentation and verification; programs are specified and described in tabular form.

  6. Structures for remotely deployable precision antennas

    NASA Technical Reports Server (NTRS)

    Hedgepeth, John M.

    1989-01-01

    There is a need for completely deployable large antenna reflectors capable of efficiently handling millimeter-wave electromagnetic radiation. The structural concepts and technologies that are appropriate to fully automated deployment of dish-type antennas with solid reflector surfaces were studied. First, the structural requirements are discussed. Then, existing concepts for fully deployable antennas are described and assessed relative to the requirements. Finally, several analyses are presented that evaluate the effects of beam steering and segmented reflector design on the accuracy of the antenna.

  7. Evaluation of High-Precision Sensors in Structural Monitoring

    PubMed Central

    Erol, Bihter

    2010-01-01

    One of the most intricate branches of metrology involves the monitoring of displacements and deformations of natural and anthropogenic structures under environmental forces, such as tidal or tectonic phenomena, or ground water level changes. Technological progress has changed the measurement process, and steadily increasing accuracy requirements have led to the continued development of new measuring instruments. The adoption of an appropriate measurement strategy, with proper instruments suited for the characteristics of the observed structure and its environmental conditions, is of high priority in the planning of deformation monitoring processes. This paper describes the use of precise digital inclination sensors in continuous monitoring of structural deformations. The topic is treated from two viewpoints: (i) evaluation of the performance of inclination sensors by comparing them to static and continuous GPS observations in deformation monitoring and (ii) providing a strategy for analyzing the structural deformations. The movements of two case study objects, a tall building and a geodetic monument in Istanbul, were separately monitored using dual-axes micro-radian precision inclination sensors (inclinometers) and GPS. The time series of continuous deformation observations were analyzed using the Least Squares Spectral Analysis Technique (LSSA). Overall, the inclinometers showed good performance for continuous monitoring of structural displacements, even at the sub-millimeter level. Static GPS observations remained insufficient for resolving the deformations to the sub-centimeter level due to the errors that affect GPS signals. With the accuracy advantage of inclination sensors, their use with GPS provides more detailed investigation of deformation phenomena. Using inclinometers and GPS is helpful to be able to identify the components of structural responses to the natural forces as static, quasi-static, or resonant. PMID:22163499

  8. Evaluation of high-precision sensors in structural monitoring.

    PubMed

    Erol, Bihter

    2010-01-01

    One of the most intricate branches of metrology involves the monitoring of displacements and deformations of natural and anthropogenic structures under environmental forces, such as tidal or tectonic phenomena, or ground water level changes. Technological progress has changed the measurement process, and steadily increasing accuracy requirements have led to the continued development of new measuring instruments. The adoption of an appropriate measurement strategy, with proper instruments suited for the characteristics of the observed structure and its environmental conditions, is of high priority in the planning of deformation monitoring processes. This paper describes the use of precise digital inclination sensors in continuous monitoring of structural deformations. The topic is treated from two viewpoints: (i) evaluation of the performance of inclination sensors by comparing them to static and continuous GPS observations in deformation monitoring and (ii) providing a strategy for analyzing the structural deformations. The movements of two case study objects, a tall building and a geodetic monument in Istanbul, were separately monitored using dual-axes micro-radian precision inclination sensors (inclinometers) and GPS. The time series of continuous deformation observations were analyzed using the Least Squares Spectral Analysis Technique (LSSA). Overall, the inclinometers showed good performance for continuous monitoring of structural displacements, even at the sub-millimeter level. Static GPS observations remained insufficient for resolving the deformations to the sub-centimeter level due to the errors that affect GPS signals. With the accuracy advantage of inclination sensors, their use with GPS provides more detailed investigation of deformation phenomena. Using inclinometers and GPS is helpful to be able to identify the components of structural responses to the natural forces as static, quasi-static, or resonant.

  9. Structures for remotely deployable precision antennas

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1989-01-01

    Future space missions such as the Earth Science Geostationary Platform (ESGP) will require highly accurate antennas with apertures that cannot be launched fully formed. The operational orbits are often inaccessible to manned flight and will involve expendable launch vehicles such as the Delta or Titan. There is therefore a need for completely deployable antenna reflectors of large size capable of efficiently handling millimeter wave electromagnetic radiation. The parameters for the type of mission are illustrated. The logarithmic plot of frequency versus aperture diameter shows the regions of interest for a large variety of space antenna applications, ranging from a 1500-meter-diameter radio telescope for low frequencies to a 20-meter-diameter infrared telescope. For the ESGP, a major application is the microwave radiometry at high frequencies for atmospheric sounding. Almost all existing large antenna reflectors for space employ a mesh-type reflecting surface. Examples are shown and discussed which deal with the various structural concepts for mesh antennas. Fortunately, those concepts are appropriate for creating the very large apertures required at the lower frequencies for good resolution. The emphasis is on the structural concepts and technologies that are appropriate to fully automated deployment of dish-type antennas with solid reflector surfaces. First the structural requirements are discussed. Existing concepts for fully deployable antennas are then described and assessed relative to the requirements. Finally, several analyses are presented that evaluate the effects of beam steering and segmented reflector design on the accuracy of the antenna.

  10. Structural analysis of the HLA-A/HLA-F subregion: Precise localization of two new multigene families closely associated with the HLA class I sequences

    SciTech Connect

    Pichon, L.; Carn, G.; Bouric, P.

    1996-03-01

    Positional cloning strategies for the hemochromatosis gene have previously concentrated on a target area restricted to a maximum genomic expanse of 400 kb around the HLA-A and HLA-F loci. Recently, the candidate region has been extended to 2-3 Mb on the distal side of the MHC. In this study, 10 coding sequences [hemochromatosis candidate genes (HCG) I to X] were isolated by cDNA selection using YACs covering the HLA-A/HLA-F subregion. Two of these (HCG II and HCG IV) belong to multigene families, as well as other sequences already described in this region, i.e., P5, pMC 6.7, and HLA class I. Fingerprinting of the four YACSs overlapping the region was performed and allowed partial localization of the different multigene family sequences on each YAC without defining their exact positions. Fingerprinting on cosmids isolated from the ICRF chromosome 6-specific cosmid library allowed more precise localization of the redundant sequences in all of the multigene families and revealed their apparent organization in clusters. Further examination of these intertwined sequences demonstrated that this structural organization resulted from a succession of complex phenomena, including duplications and contractions. This study presents a precise description of the structural organization of the HLA-A/HLA-F region and a determination of the sequences involved in the megabase size polymorphism observed among the A3, A24, and A31 haplotypes. 29 refs., 2 figs., 2 tabs.

  11. Active vibration control in precision structures

    NASA Astrophysics Data System (ADS)

    Yen, Gary G.

    1997-04-01

    This paper discusses the developed Adaptive Neural Control architecture for on-line system identification and real-time adaptive control. After reviewing existing literature involving controls of structural vibration, we report new developments carried out under the adaptive neural control program for the USAF Phillips Laboratory. The new results include a neural control architecture suitable for MIMO systems subjected to tonal disturbances that is capable of optimizing vibration suppression in the presence of sensor or actuator failures. This architecture was demonstrated in a series of tests on the ASTREX facility.

  12. CD-SEM precision: improved procedure and analysis

    NASA Astrophysics Data System (ADS)

    Menaker, Mina

    1999-06-01

    Accurate precision assessment becomes increasingly important as we proceed along the SIA road map, in to more advanced processes and smaller critical dimensions. Accurate precision is necessary in order to determine the P/T ratio which is used to decide whether a specific CD-SEM is valid for controlling a specific process. The customer's needs, as been presented by the SEMATECH Advanced Metrology Advisory Group, are to receive a detailed precision report, in the form of a full repeatability and reproducibility (RR) analysis. The 3 sigma single tool RR, of an in-line SEM, are determined in the same operational modes as used in production, and should include the effects of time and process variants on the SEM performance. We hereby present an RR procedure by a modulate approach which enables the user extending the evaluation according to her/his needs. It includes direct assessment of repeatability, reproducibility and stability analysis. It also allows for a study of wafer non homogeneity, induced process variation and a measured feature type effect on precision. The procedure is based on the standard ISO RR procedure, and includes a modification for a correct compensation for bias, or so called measurement turned. A close examination of the repeatability and reproducibility variations, provides insight to the possible sources of those variations, such as S/N ratio, SEM autofocus mechanism, automation etc. For example, poor wafer alignment might not effect the repeatability, but severally reduce reproducibility. Therefore the analysis is a key to better understanding and improving of CD-SEM performance, on production layers. The procedure is fully implemented on an automated CD-SEM, providing on line precision assessment. RR < 1 nm has been demonstrated on well defined resist and etched structures. Examples of the automatic analysis results, using the new procedure are presented.

  13. Computer-Aided High Precision Verification Of Miniature Spring Structure

    NASA Astrophysics Data System (ADS)

    Bow, Sing T.; Wang, Da-hao; Chen, Tsung-sheng; Newell, Darrell E.

    1990-01-01

    A system is proposed for the high precision on-line verification of the minia-ture spring structure, including overall height, diameters of various coils as well as pitches between neighboring coils of the miniature conical springs. High preci-sion measurements without physical contact and short processing time are achieved. Deformations of any kind on the conical springs can be identified even from the worst viewing direction.

  14. Precision exploration of neutron spin structure at Jefferson Lab

    SciTech Connect

    Nilanga Liyanage

    2003-08-01

    Spin structure functions provide basic information about the spin of the quark distributions inside the nucleon. Experimental understanding of the nucleon spin in the kinematic region where the three basic (''valence'') quarks dominate the nucleon wave function is still rather poor. Jefferson lab, with its high quality, high polarization continuous electron beam, and a high density polarized 3He target in experimental Hall A, provides the ideal opportunity to gather neutron spin structure data in the valence region with unprecedented precision. Two high precision neutron spin structure measurements were completed in Hall A last summer. The first experiment measured the spin asymmetry A1(N) in the valence region while in second experiment higher-twist effects were studied via measurements of gn2. The planed upgrade of Jefferson lab CEBAF accelerator to 12 GeV will significantly increase the accessible kinematic range and the precision of these measurements.

  15. Experimental evaluation of active-member control of precision structures

    NASA Technical Reports Server (NTRS)

    Fanson, James; Blackwood, Gary; Chu, Cheng-Chih

    1989-01-01

    The results of closed loop experiments that use piezoelectric active-members to control the flexible motion of a precision truss structure are described. These experiments are directed toward the development of high-performance structural systems as part of the Control/Structure Interaction (CSI) program at JPL. The focus of CSI activity at JPL is to develop the technology necessary to accurately control both the shape and vibration levels in the precision structures from which proposed large space-based observatories will be built. Structural error budgets for these types of structures will likely be in the sub-micron regime; optical tolerances will be even tighter. In order to achieve system level stability and local positioning at this level, it is generally expected that some form of active control will be required.

  16. Design and implementation of active members for precision space structures

    NASA Technical Reports Server (NTRS)

    Webster, M. S.; Fanson, J. L.; Lurie, B. J.; O'Brien, J. F.

    1992-01-01

    This paper describes the development and implementation of an active member in a precision truss structure. The active member utilizes a piezoelectric actuator motor imbedded in a steel case with built-in displacement sensor. This active member is used in structural quieting. Collocated active damping control loops are designed in order to impedance match piezoelectric active members to the structure. Results from application of these controllers and actuators to the JPL Phase B testbed are given.

  17. Precise Analysis of Polymer Rotational Dynamics

    PubMed Central

    Kim, Jun Mo; Baig, Chunggi

    2016-01-01

    Through the analysis of individual chain dynamics alongside the corresponding molecular structures under shear via nonequilibrium molecular dynamics simulations of C178H358 linear and short-chain branched polyethylene melts under shear flow, we observed that the conventional method based on the chain end-to-end vector (and/or the gyration tensor of chain) is susceptible to quantitatively inaccurate measurements and often misleading information in describing the rotational dynamics of polymers. Identifying the flaw as attributed to strong irregular Brownian fluctuations inherent to the chain ends associated with their large free volume and strong molecular collisions, we propose a simple, robust way based on the chain center-to-center vector connecting the two centers of mass of the bisected chain, which is shown to adequately describe polymer rotational dynamics without such shortcomings. We present further consideration that the proposed method can be useful in accurately measuring the overall chain structure and dynamics of polymeric materials with various molecular architectures, including branched and ring polymers. PMID:26743689

  18. Vibration suppression for Precision Segmented Reflector backup structure.

    NASA Astrophysics Data System (ADS)

    Chen, G. S.; Garba, J. A.; Wada, B. K.

    1989-09-01

    This paper describes an ongoing effort at the JPL on the vibration suppression for the Precision Segmented Reflector backup structure. The effort is centered on the vibration damping augmentation through a system consisting of active and passive damping members. An active member is a structural member with built-in piezoelectric actuator and sensors. A bridge feedback technique developed in the communication engineering is applied locally to the active member for active damping augmentation.

  19. Fully Nonlinear Modeling and Analysis of Precision Membranes

    NASA Technical Reports Server (NTRS)

    Pai, P. Frank; Young, Leyland G.

    2003-01-01

    High precision membranes are used in many current space applications. This paper presents a fully nonlinear membrane theory with forward and inverse analyses of high precision membrane structures. The fully nonlinear membrane theory is derived from Jaumann strains and stresses, exact coordinate transformations, the concept of local relative displacements, and orthogonal virtual rotations. In this theory, energy and Newtonian formulations are fully correlated, and every structural term can be interpreted in terms of vectors. Fully nonlinear ordinary differential equations (ODES) governing the large static deformations of known axisymmetric membranes under known axisymmetric loading (i.e., forward problems) are presented as first-order ODES, and a method for obtaining numerically exact solutions using the multiple shooting procedure is shown. A method for obtaining the undeformed geometry of any axisymmetric membrane with a known inflated geometry and a known internal pressure (i.e., inverse problems) is also derived. Numerical results from forward analysis are verified using results in the literature, and results from inverse analysis are verified using known exact solutions and solutions from the forward analysis. Results show that the membrane theory and the proposed numerical methods for solving nonlinear forward and inverse membrane problems are accurate.

  20. Precise Identification of Graphene's Crystal Structures by Removable Nanowire Epitaxy.

    PubMed

    Kim, Jonghyeok; Lim, Kitaek; Lee, Yangjin; Kim, Jongin; Kim, Kihwan; Park, Jungwon; Kim, Kwanpyo; Lee, Won Chul

    2017-03-16

    Monitoring crystallographic orientations of graphene is important for the reliable generation of graphene-based nanostructures such as van der Waals heterostructures and graphene nanoribbons because their physical properties are dependent on crystal structures. However, facile and precise identification of graphene's crystallographic orientations is still challenging because the majority of current tools rely on complex atomic-scale imaging. Here, we present an identification method for the crystal orientations and grain boundaries of graphene using the directional alignment between epitaxially grown AuCN nanowires and the underlying graphene. Because the nanowires are visible in scanning electron microscopy, crystal orientations of graphene can be inspected with simple procedures. Kernel density estimation that we used in analyzing the nanowire directions enables precise measurement of graphene's crystal orientations. We also confirm that the imaged nanowires can be simply removed without degrading graphene's quality, thus showing that the present method can be practically used for measuring graphene's crystal structures.

  1. The Precision Efficacy Analysis for Regression Sample Size Method.

    ERIC Educational Resources Information Center

    Brooks, Gordon P.; Barcikowski, Robert S.

    The general purpose of this study was to examine the efficiency of the Precision Efficacy Analysis for Regression (PEAR) method for choosing appropriate sample sizes in regression studies used for precision. The PEAR method, which is based on the algebraic manipulation of an accepted cross-validity formula, essentially uses an effect size to…

  2. High precision analysis of an embryonic extensional fault-related fold using 3D orthorectified virtual outcrops: The viewpoint importance in structural geology

    NASA Astrophysics Data System (ADS)

    Tavani, Stefano; Corradetti, Amerigo; Billi, Andrea

    2016-05-01

    Image-based 3D modeling has recently opened the way to the use of virtual outcrop models in geology. An intriguing application of this method involves the production of orthorectified images of outcrops using almost any user-defined point of view, so that photorealistic cross-sections suitable for numerous geological purposes and measurements can be easily generated. These purposes include the accurate quantitative analysis of fault-fold relationships starting from imperfectly oriented and partly inaccessible real outcrops. We applied the method of image-based 3D modeling and orthorectification to a case study from the northern Apennines, Italy, where an incipient extensional fault affecting well-layered limestones is exposed on a 10-m-high barely accessible cliff. Through a few simple steps, we constructed a high-quality image-based 3D model of the outcrop. In the model, we made a series of measurements including fault and bedding attitudes, which allowed us to derive the bedding-fault intersection direction. We then used this direction as viewpoint to obtain a distortion-free photorealistic cross-section, on which we measured bed dips and thicknesses as well as fault stratigraphic separations. These measurements allowed us to identify a slight difference (i.e. only 0.5°) between the hangingwall and footwall cutoff angles. We show that the hangingwall strain required to compensate the upward-decreasing displacement of the fault was accommodated by this 0.5° rotation (i.e. folding) and coeval 0.8% thickening of strata in the hangingwall relatively to footwall strata. This evidence is consistent with trishear fault-propagation folding. Our results emphasize the viewpoint importance in structural geology and therefore the potential of using orthorectified virtual outcrops.

  3. Precise Specification of Design Pattern Structure and Behaviour

    NASA Astrophysics Data System (ADS)

    Sterritt, Ashley; Clarke, Siobhán; Cahill, Vinny

    Applying design patterns while developing a software system can improve its non-functional properties, such as extensibility and loose coupling. Precise specification of structure and behaviour communicates the invariants imposed by a pattern on a conforming implementation and enables formal software verification. Many existing design-pattern specification languages (DPSLs) focus on class structure alone, while those that do address behaviour suffer from a lack of expressiveness and/or imprecise semantics. In particular, in a review of existing work, three invariant categories were found to be inexpressible in state-of-the-art DPSLs: dependency, object state and data-structure. This paper presents Alas: a precise specification language that supports design-pattern descriptions including these invariant categories. The language is based on UML Class and Sequence diagrams with modified syntax and semantics. In this paper, the meaning of the presented invariants is formalized and relevant ambiguities in the UML Standard are clarified. We have evaluated Alas by specifying the widely-used Gang of Four pattern catalog and identified patterns that benefitted from the added expressiveness and semantics of Alas.

  4. Structural Analysis

    NASA Technical Reports Server (NTRS)

    1991-01-01

    After an 800-foot-tall offshore oil recovery platform collapsed, the engineers at Engineering Dynamics, Inc., Kenner, LA, needed to learn the cause of the collapse, and analyze the proposed repairs. They used STAGSC-1, a NASA structural analysis program with geometric and nonlinear buckling analysis. The program allowed engineers to determine the deflected and buckling shapes of the structural elements. They could then view the proposed repairs under the pressure that caused the original collapse.

  5. Precise Calculation of Traveling-Wave Periodic Structure

    SciTech Connect

    Wang, L.; Li, Z.; Seryi, A.; /SLAC

    2007-07-06

    The effects of the round edge beam hole on the frequency and wake field are studied using variational method, which allows for rounded iris disk hole without any approximation in shape treatment. The frequency and wake field of accelerating mode and dipole mode are studied for different edge radius cases, including the flat edge shape that is often used to approximately represent the actual structure geometry. The edge hole shape has weak effect on the frequency, but much effect on the wake field. Our study shows that the amounts of wake fields are not precise enough with the assumption of the flat edge beam hole instead of round edge.

  6. The Precision Formation Flying Integrated Analysis Tool (PFFIAT)

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric; Lyon, Richard G.; Sears, Edie; Lu, Victor

    2004-01-01

    Several space missions presently in the concept phase (e.g. Stellar Imager, Sub- millimeter Probe of Evolutionary Cosmic Structure, Terrestrial Planet Finder) plan to use multiple spacecraft flying in precise formation to synthesize unprecedently large aperture optical systems. These architectures present challenges to the attitude and position determination and control system; optical performance is directly coupled to spacecraft pointing with typical control requirements being on the scale of milliarcseconds and nanometers. To investigate control strategies, rejection of environmental disturbances, and sensor and actuator requirements, a capability is needed to model both the dynamical and optical behavior of such a distributed telescope system. This paper describes work ongoing at NASA Goddard Space Flight Center toward the integration of a set of optical analysis tools (Optical System Characterization and Analysis Research software, or OSCAR) with the Formation J?lying Test Bed (FFTB). The resulting system is called the Precision Formation Flying Integrated Analysis Tool (PFFIAT), and it provides the capability to simulate closed-loop control of optical systems composed of elements mounted on multiple spacecraft. The attitude and translation spacecraft dynamics are simulated in the FFTB, including effects of the space environment (e.g. solar radiation pressure, differential orbital motion). The resulting optical configuration is then processed by OSCAR to determine an optical image. From this image, wavefront sensing (e.g. phase retrieval) techniques are being developed to derive attitude and position errors. These error signals will be fed back to the spacecraft control systems, completing the control loop. A simple case study is presented to demonstrate the present capabilities of the tool.

  7. The Precision Formation Flying Integrated Analysis Tool (PFFIAT)

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric; Lyon, Richard G.; Sears, Edie; Lu, Victor

    2004-01-01

    Several space missions presently in the concept phase (e.g. Stellar Imager, Submillimeter Probe of Evolutionary Cosmic Structure, Terrestrial Planet Finder) plan to use multiple spacecraft flying in precise formation to synthesize unprecedently large aperture optical systems. These architectures present challenges to the attitude and position determination and control system; optical performance is directly coupled to spacecraft pointing with typical control requirements being on the scale of milliarcseconds and nanometers. To investigate control strategies, rejection of environmental disturbances, and sensor and actuator requirements, a capability is needed to model both the dynamical and optical behavior of such a distributed telescope system. This paper describes work ongoing at NASA Goddard Space Flight Center toward the integration of a set of optical analysis tools (Optical System Characterization and Analysis Research software, or OSCAR) with the Formation Flying Test Bed (FFTB). The resulting system is called the Precision Formation Flying Integrated Analysis Tool (PFFIAT), and it provides the capability to simulate closed-loop control of optical systems composed of elements mounted on multiple spacecraft. The attitude and translation spacecraft dynamics are simulated in the FFTB, including effects of the space environment (e.g. solar radiation pressure, differential orbital motion). The resulting optical configuration is then processed by OSCAR to determine an optical image. From this image, wavefront sensing (e.g. phase retrieval) techniques are being developed to derive attitude and position errors. These error signals will be fed back to the spacecraft control systems, completing the control loop. A simple case study is presented to demonstrate the present capabilities of the tool.

  8. Precise rare earth analysis of geological materials

    SciTech Connect

    Laul, J.C.; Wogman, N.A.

    1982-01-01

    Rare earth element (REE) concentrations are very informative in revealing chemical fractionation processs in geological systems. The REE's (La-Lu) behavior is characteristic of various primary and secondary minerals which comprise a rock. The REE's contents and their patterns provide a strong fingerprint in distinguishing among various rock types and in understanding the partial melting and/or fractional crystallization of the source region. The REE contents in geological materials are usually at trace levels. To measure all the REE at such levels, radiochemical neutron activation analysis (RNAA) has been used with a REE group separation scheme. To maximize detection sensitivites for individual REE, selective ..gamma..-ray/x-ray measurements have been made using normal Ge(Li) and low-energy photon detectors (LEPD), and Ge(Li)-NaI(Tl) coincidence-noncoincidence spectrometer systems. Using these detection methods an individual REE can be measured at or below the ppB levels; chemical yields of the REE are determined by reactivation.

  9. Advanced Smart Structures Flight Experiments for Precision Spacecraft

    NASA Astrophysics Data System (ADS)

    Denoyer, Keith K.; Erwin, R. Scott; Ninneman, R. Rory

    2000-07-01

    This paper presents an overview as well as data from four smart structures flight experiments directed by the U.S. Air Force Research Laboratory's Space Vehicles Directorate in Albuquerque, New Mexico. The Middeck Active Control Experiment $¯Flight II (MACE II) is a space shuttle flight experiment designed to investigate modeling and control issues for achieving high precision pointing and vibration control of future spacecraft. The Advanced Controls Technology Experiment (ACTEX-I) is an experiment that has demonstrated active vibration suppression using smart composite structures with embedded piezoelectric sensors and actuators. The Satellite Ultraquiet Isolation Technology Experiment (SUITE) is an isolation platform that uses active piezoelectric actuators as well as damped mechanical flexures to achieve hybrid passive/active isolation. The Vibration Isolation, Suppression, and Steering Experiment (VISS) is another isolation platform that uses viscous dampers in conjunction with electromagnetic voice coil actuators to achieve isolation as well as a steering capability for an infra-red telescope.

  10. Mass Efficiencies for Common Large-Scale Precision Space Structures

    NASA Technical Reports Server (NTRS)

    Williams, R. Brett; Agnes, Gregory S.

    2005-01-01

    This paper presents a mass-based trade study for large-scale deployable triangular trusses, where the longerons can be monocoque tubes, isogrid tubes, or coilable longeron trusses. Such structures are typically used to support heavy reflectors, solar panels, or other instruments, and are subject to thermal gradients that can vary a great deal based on orbital altitude, location in orbit, and self-shadowing. While multi layer insulation (MLI) blankets are commonly used to minimize the magnitude of these thermal disturbances, they subject the truss to a nonstructural mass penalty. This paper investigates the impact of these add-on thermal protection layers on selecting the lightest precision structure for a given loading scenario.

  11. System and method for high precision isotope ratio destructive analysis

    DOEpatents

    Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

    2013-07-02

    A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

  12. Spatially Resolved Electronic Structures of Atomically Precise Armchair Graphene Nanoribbons

    PubMed Central

    Huang, Han; Wei, Dacheng; Sun, Jiatao; Wong, Swee Liang; Feng, Yuan Ping; Neto, A. H. Castro; Wee, Andrew Thye Shen

    2012-01-01

    Graphene has attracted much interest in both academia and industry. The challenge of making it semiconducting is crucial for applications in electronic devices. A promising approach is to reduce its physical size down to the nanometer scale. Here, we present the surface-assisted bottom-up fabrication of atomically precise armchair graphene nanoribbons (AGNRs) with predefined widths, namely 7-, 14- and 21-AGNRs, on Ag(111) as well as their spatially resolved width-dependent electronic structures. STM/STS measurements reveal their associated electron scattering patterns and the energy gaps over 1 eV. The mechanism to form such AGNRs is addressed based on the observed intermediate products. Our results provide new insights into the local properties of AGNRs, and have implications for the understanding of their electrical properties and potential applications. PMID:23248746

  13. Precision Polyolefin Structure: Modeling Polyethylene Containing Methyl and Ethyl Branches

    NASA Astrophysics Data System (ADS)

    Rojas, Giovanni; Wagener, Kenneth B.

    Sequenced copolymers of ethylene and diverse species have been created using acyclic diene metathesis (ADMET) polymerization, a step growth, condensation- type polymerization driven to high conversion by the removal of ethylene. ADMET permits control over branch content and branch length, which can be predetermined during the monomer synthesis, allowing sequence control in the resultant unsaturated polymer. Monomers are symmetrical α,ωdienes with a pendant functionality. Diverse functional groups are compatible with ADMET polymerization when Schrock’s or first-generation Grubb’s catalysts are used. Saturation with hydrogen after ADMET polymerization affords a polyethylene (PE) backbone bearing specific functionalities in precise places. Varying both the pendant functional group and the spacing between functionalities alters the physical and chemical properties of the polymer. Incorporation of alkyl chains into the PE backbone via ADMET leads to the study of perfect structures modeling the copolymerization of ethylene with α-olefins such as 1-propene, 1-butene, 1-hexene, and 1-octene.

  14. Rapid and precise analysis for calcium in blood serum

    NASA Technical Reports Server (NTRS)

    Holtzman, R. B.; Ilcewicz, F. H.

    1969-01-01

    Differential absorption spectrophotometric technique, using murexide, gives a highly precise analysis of calcium in volumes of blood serum as small as 0.01 ml. The method of additions and proper timing allows compensation to be made for fading, variation in type of serum or plasma, and aging of the specimen.

  15. An instrument for precision magnetic measurements of large magnetic structures

    NASA Astrophysics Data System (ADS)

    Beltrán, D.; Bordas, J.; Campmany, J.; Molins, A.; Perlas, J. A.; Traveria, M.

    2001-02-01

    A high precision-system for measuring the three-dimensional distribution of magnetic fields over large volumes, such as those produced by accelerator magnets, has been designed and commissioned. This instrument can be calibrated to a precision of ±1 G for magnetic fields of up to 1.5 T by means of an NMR system. A moving arm containing a 3D Hall probe scans the volume (up to 500×250×3000 mm 3) with a precision of ±50 μm in any direction. After appropriate identification of the various sources of error, and the optimisation of the various parts of the instrument where they are generated, an overall precision of ±2 G has been achieved, i.e. a relative precision of ±2×10 -4 for a nominal field of 1 T.

  16. Determination of LAGEOS satellite's precise orbits and residual analysis

    NASA Astrophysics Data System (ADS)

    Feng, C. G.; Zhang, F. P.; Zhu, Y. L.

    2003-02-01

    Determination of LAGEOS satellite's precise orbits based on an analysis residual error of SLR data are introduced in detail. The method analyzing the data of satellite laser ranging (SLR)?the dynamical models used and the number of parameters estimated should be changed with the different purposes. The schemes were compared with each other and were analyzed with the number of parameters estimated and the residual errors in detail. The determination of precise orbits is the key of these. To acquire a precise orbit, the models determining the EOP were modified. The scheme being used by SHAO was selected from the several schemes. In this paper, the results of LAGEOS satellite's precise orbits from Dec. 31, 1998 to Jun. 29, 2001 are set out only. The results show that the root-mean square value of the residuals are less than 2cm. SHAO has begun the service of LAGEOS-1/LAGEOS-2 quick-look residual analysis since Oct.1, 1999. The results can be find on the intent address: http://center.shao.ac.cn/APSG/result

  17. Dipole model analysis of high precision HERA data

    NASA Astrophysics Data System (ADS)

    Luszczak, A.; Kowalski, H.

    2014-04-01

    We analyze, within a dipole model, the inclusive deep inelastic scattering cross section data, obtained from the combination of the measurements of the H1 and ZEUS experiments performed at the HERA collider. We show that these high precision data are very well described within the dipole model framework, which is complemented with valence quark structure functions. We discuss the properties of the gluon density obtained in this way.

  18. Experimental studies of adaptive structures for precision performance

    NASA Technical Reports Server (NTRS)

    Chen, G.-S.; Lurie, B. J.; Wada, B. K.

    1989-01-01

    An experimental study was made of the adaptive structure concept. Experimental data were obtained for a three-longeron, thirteen-bay truss-type test structure. This test structure can be softly suspended as well as rigidly clamped at the central bay. The load-carrying active member consists of a stack of concentric piezoelectric wafers, an eddy current displacement sensor, and a strain gage force sensor. A bridge (or compound) feedback technique developed in communication engineering is applied to the problem of active damping augmentation in adaptive structures. Using collocated force and velocity feedback around the active member, a desired output mechanical impedance can be implemented to maximize energy absorption by the active members. In addition, large gains can be implemented to linearize the active member's nonlinear behavior. Good agreements with linear finite element analysis was found for both static and dynamic structural responses. An 11 percent damping in the first bending mode was demonstrated in the closed-loop damping experiment.

  19. Multidimensional Image Analysis for High Precision Radiation Therapy.

    PubMed

    Arimura, Hidetaka; Soufi, Mazen; Haekal, Mohammad

    2017-01-01

    High precision radiation therapy (HPRT) has been improved by utilizing conventional image engineering technologies. However, different frameworks are necessary for further improvement of HPRT. This review paper attempted to define the multidimensional image and what multidimensional image analysis is, which may be feasible for increasing the accuracy of HPRT. A number of researches in radiation therapy field have been introduced to understand the multidimensional image analysis. Multidimensional image analysis could greatly assist clinical staffs in radiation therapy planning, treatment, and prediction of treatment outcomes.

  20. Structured beam shaping for precision laser dicing of multilayered substrates

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd; Ohar, Orest

    2007-02-01

    Laser dicing of wafer based devices; such as light emitting diodes (LEDs) is multifaceted since these devices are formed from various materials in a layered structure. Many of these layers include active device materials, passivation coatings, conductors and dielectric films all deposited on top of a bulk wafer substrate and all potentially having different ablation thresholds. These composite multi-layered structures require high finesse laser processes to ensure yields, high quality and low cost. Such processes have become very complex over the years as new devices become miniaturized, requiring smaller micro-machined features, greater precision and reduction of thermal stress to minimize substrate micro-cracking and maintain device integrity over its projected lifetime. Newer laser processes often involve the sequential use of single or multiple diode pumped solid state (DPSS) lasers, such as UV DPSS (355nn, 266nm), VIS DPSS (~532 nm) and IR DPSS (1064nm, 1070nm) as well as DPFL (Diode Pumped Fiber Lasers) lasers to penetrate various and differing material layers and substrates including SiC, Silicon and Sapphire. Development of beam shaping optics with the purpose of permitting two or more differing energy densities within a single focused or imaged beam spot would provide opportunities for pre-processing or pre-scribing of thinner cover layers, while following through with a higher energy density portion to cut through base substrates. This technique is also possible using multiple wavelengths simultaneously for micro-machining or dicing. Using multiple wavelengths offers advantages where high photon energies from such wavelengths as 266 nm can cause adverse effects to doped materials such as silicon or to active device layers such as GaN or other III-V materials deposited on the substrate surface. This paper will describe the development of variable intensity beam shaping optical elements targeting micromachining, dicing and patterning of delicate thin film

  1. Precision measurement of the neutron spin dependent structure functions

    SciTech Connect

    Kolomensky, Y.G.

    1997-02-01

    In experiment E154 at the Stanford Linear Accelerator Center the spin dependent structure function g{sub 1}{sup n} (x, Q{sup 2}) of the neutron was measured by scattering longitudinally polarized 48.3 GeV electrons off a longitudinally polarized {sup 3}He target. The high beam energy allowed the author to extend the kinematic coverage compared to the previous SLAC experiments to 0.014 {le} x {le} 0.7 with an average Q{sup 2} of 5 GeV{sup 2}. The author reports the integral of the spin dependent structure function in the measured range to be {integral}{sub 0.014}{sup 0.7} dx g{sub 1}{sup n}(x, 5 GeV{sup 2}) = {minus}0.036 {+-} 0.004(stat.) {+-} 0.005(syst.). The author observes relatively large values of g{sub 1}{sup n} at low x that call into question the reliability of data extrapolation to x {r_arrow} 0. Such divergent behavior disagrees with predictions of the conventional Regge theory, but is qualitatively explained by perturbative QCD. The author performs a Next-to-Leading Order perturbative QCD analysis of the world data on the nucleon spin dependent structure functions g{sub 1}{sup p} and g{sub 1}{sup n} paying careful attention to the experimental and theoretical uncertainties. Using the parameterizations of the helicity-dependent parton distributions obtained in the analysis, the author evolves the data to Q{sup 2} = 5 GeV{sup 2}, determines the first moments of the polarized structure functions of the proton and neutron, and finds agreement with the Bjorken sum rule.

  2. Control-structure interaction in precision pointing servo loops

    NASA Technical Reports Server (NTRS)

    Spanos, John T.

    1989-01-01

    The control-structure interaction problem is addressed via stability analysis of a generic linear servo loop model. With the plant described by the rigid body mode and a single elastic mode, structural flexibility is categorized into one of three types: (1) appendage, (2) in-the-loop minimum phase, and (3) in-the-loop nonminimum phase. Closing the loop with proportional-derivative (PD) control action and introducing sensor roll-off dynamics in the feedback path, stability conditions are obtained. Trade studies are conducted with modal frequency, modal participation, modal damping, loop bandwidth, and sensor bandwidth treated as free parameters. Results indicate that appendage modes are most likely to produce instability if they are near the sensor rolloff, whereas in-the-loop modes are most dangerous near the loop bandwidth. The main goal of this paper is to provide a fundamental understanding of the control-structure interaction problem so that it may benefit the design of complex spacecraft and pointing system servo loops. In this framework, the JPL Pathfinder gimbal pointer is considered as an example.

  3. Precision of Sensitivity in the Design Optimization of Indeterminate Structures

    NASA Technical Reports Server (NTRS)

    Patnaik, Surya N.; Pai, Shantaram S.; Hopkins, Dale A.

    2006-01-01

    Design sensitivity is central to most optimization methods. The analytical sensitivity expression for an indeterminate structural design optimization problem can be factored into a simple determinate term and a complicated indeterminate component. Sensitivity can be approximated by retaining only the determinate term and setting the indeterminate factor to zero. The optimum solution is reached with the approximate sensitivity. The central processing unit (CPU) time to solution is substantially reduced. The benefit that accrues from using the approximate sensitivity is quantified by solving a set of problems in a controlled environment. Each problem is solved twice: first using the closed-form sensitivity expression, then using the approximation. The problem solutions use the CometBoards testbed as the optimization tool with the integrated force method as the analyzer. The modification that may be required, to use the stiffener method as the analysis tool in optimization, is discussed. The design optimization problem of an indeterminate structure contains many dependent constraints because of the implicit relationship between stresses, as well as the relationship between the stresses and displacements. The design optimization process can become problematic because the implicit relationship reduces the rank of the sensitivity matrix. The proposed approximation restores the full rank and enhances the robustness of the design optimization method.

  4. A unique approach to fabricating precision space structures elements

    NASA Technical Reports Server (NTRS)

    Cohan, H.; Johnson, R. R.

    1981-01-01

    A procedure of fabricating graphite epoxy columns used in the assembly of large space platforms is described. The requirement for precise dimensional control led to a unique hot resin injection process. Dry, high modulus fiber is wound over a vertically mounted steam-heated mandrel. A steam-heated sleeve or caul is slipped over the wound mandrel and resin is injected and cured in place. Approximately 200 column elements have been fabricated using this efficient process.

  5. Do we see what we should see? Describing non-covalent interactions in protein structures including precision.

    PubMed

    Gurusaran, Manickam; Shankar, Mani; Nagarajan, Raju; Helliwell, John R; Sekar, Kanagaraj

    2014-01-01

    The power of X-ray crystal structure analysis as a technique is to 'see where the atoms are'. The results are extensively used by a wide variety of research communities. However, this 'seeing where the atoms are' can give a false sense of security unless the precision of the placement of the atoms has been taken into account. Indeed, the presentation of bond distances and angles to a false precision (i.e. to too many decimal places) is commonplace. This article has three themes. Firstly, a basis for a proper representation of protein crystal structure results is detailed and demonstrated with respect to analyses of Protein Data Bank entries. The basis for establishing the precision of placement of each atom in a protein crystal structure is non-trivial. Secondly, a knowledge base harnessing such a descriptor of precision is presented. It is applied here to the case of salt bridges, i.e. ion pairs, in protein structures; this is the most fundamental place to start with such structure-precision representations since salt bridges are one of the tenets of protein structure stability. Ion pairs also play a central role in protein oligomerization, molecular recognition of ligands and substrates, allosteric regulation, domain motion and α-helix capping. A new knowledge base, SBPS (Salt Bridges in Protein Structures), takes these structural precisions into account and is the first of its kind. The third theme of the article is to indicate natural extensions of the need for such a description of precision, such as those involving metalloproteins and the determination of the protonation states of ionizable amino acids. Overall, it is also noted that this work and these examples are also relevant to protein three-dimensional structure molecular graphics software.

  6. Do we see what we should see? Describing non-covalent interactions in protein structures including precision

    PubMed Central

    Gurusaran, Manickam; Shankar, Mani; Nagarajan, Raju; Helliwell, John R.; Sekar, Kanagaraj

    2014-01-01

    The power of X-ray crystal structure analysis as a technique is to ‘see where the atoms are’. The results are extensively used by a wide variety of research communities. However, this ‘seeing where the atoms are’ can give a false sense of security unless the precision of the placement of the atoms has been taken into account. Indeed, the presentation of bond distances and angles to a false precision (i.e. to too many decimal places) is commonplace. This article has three themes. Firstly, a basis for a proper representation of protein crystal structure results is detailed and demonstrated with respect to analyses of Protein Data Bank entries. The basis for establishing the precision of placement of each atom in a protein crystal structure is non-trivial. Secondly, a knowledge base harnessing such a descriptor of precision is presented. It is applied here to the case of salt bridges, i.e. ion pairs, in protein structures; this is the most fundamental place to start with such structure-precision representations since salt bridges are one of the tenets of protein structure stability. Ion pairs also play a central role in protein oligomerization, molecular recognition of ligands and substrates, allosteric regulation, domain motion and α-helix capping. A new knowledge base, SBPS (Salt Bridges in Protein Structures), takes these structural precisions into account and is the first of its kind. The third theme of the article is to indicate natural extensions of the need for such a description of precision, such as those involving metalloproteins and the determination of the protonation states of ionizable amino acids. Overall, it is also noted that this work and these examples are also relevant to protein three-dimensional structure molecular graphics software. PMID:25075321

  7. The Structure and Precision of Retinal Spike Trains

    NASA Astrophysics Data System (ADS)

    Berry, Michael J.; Warland, David K.; Meister, Markus

    1997-05-01

    Assessing the reliability of neuronal spike trains is fundamental to an understanding of the neural code. We measured the reproducibility of retinal responses to repeated visual stimuli. In both tiger salamander and rabbit, the retinal ganglion cells responded to random flicker with discrete, brief periods of firing. For any given cell, these firing events covered only a small fraction of the total stimulus time, often less than 5%. Firing events were very reproducible from trial to trial: the timing jitter of individual spikes was as low as 1 msec, and the standard deviation in spike count was often less than 0.5 spikes. Comparing the precision of spike timing to that of the spike count showed that the timing of a firing event conveyed several times more visual information than its spike count. This sparseness and precision were general characteristics of ganglion cell responses, maintained over the broad ensemble of stimulus waveforms produced by random flicker, and over a range of contrasts. Thus, the responses of retinal ganglion cells are not properly described by a firing probability that varies continuously with the stimulus. Instead, these neurons elicit discrete firing events that may be the fundamental coding symbols in retinal spike trains.

  8. Creating and testing large space structures of high precision surface

    NASA Astrophysics Data System (ADS)

    Medzmariashvili, Elgudja; Iacobashvili, Alexander; Beducadze, Guram

    The authors describe work on the development of large structures for use in space. This work involves development of structural classes (types), theoretical studis, systems manufacturing and full scale structure testing. Collecting solar energy in space and sending it down to Earth is of great interest to humanity because of the large need for energy on Earth. Building any large solar power station requires industry and construction engineering in space. The problem, as a whole, as well as specific parts thereof virtually always requires certain engineering support, i.e. erection of supporting, reflecting and other large-sized structures in orbit. The Institute of Transformed Structures carries out research, design manufacturing, ground testing and supply of launchable prototypes. The work is performed in an unified manner and contains several trends (categories) which define structures that can be assembled in space.

  9. Advancing sensitivity analysis to precisely characterize temporal parameter dominance

    NASA Astrophysics Data System (ADS)

    Guse, Björn; Pfannerstill, Matthias; Strauch, Michael; Reusser, Dominik; Lüdtke, Stefan; Volk, Martin; Gupta, Hoshin; Fohrer, Nicola

    2016-04-01

    Parameter sensitivity analysis is a strategy for detecting dominant model parameters. A temporal sensitivity analysis calculates daily sensitivities of model parameters. This allows a precise characterization of temporal patterns of parameter dominance and an identification of the related discharge conditions. To achieve this goal, the diagnostic information as derived from the temporal parameter sensitivity is advanced by including discharge information in three steps. In a first step, the temporal dynamics are analyzed by means of daily time series of parameter sensitivities. As sensitivity analysis method, we used the Fourier Amplitude Sensitivity Test (FAST) applied directly onto the modelled discharge. Next, the daily sensitivities are analyzed in combination with the flow duration curve (FDC). Through this step, we determine whether high sensitivities of model parameters are related to specific discharges. Finally, parameter sensitivities are separately analyzed for five segments of the FDC and presented as monthly averaged sensitivities. In this way, seasonal patterns of dominant model parameter are provided for each FDC segment. For this methodical approach, we used two contrasting catchments (upland and lowland catchment) to illustrate how parameter dominances change seasonally in different catchments. For all of the FDC segments, the groundwater parameters are dominant in the lowland catchment, while in the upland catchment the controlling parameters change seasonally between parameters from different runoff components. The three methodical steps lead to clear temporal patterns, which represent the typical characteristics of the study catchments. Our methodical approach thus provides a clear idea of how the hydrological dynamics are controlled by model parameters for certain discharge magnitudes during the year. Overall, these three methodical steps precisely characterize model parameters and improve the understanding of process dynamics in hydrological

  10. High-precision structure fabrication based on an etching resistance layer

    NASA Astrophysics Data System (ADS)

    Zhang, Man; Deng, Qiling; Shi, Lifang; Cao, Axiu; Pang, Hui; Liu, Xin; Wang, Jiazhou; Hu, Song

    2016-10-01

    The high-precision fabrication of micro-/nano-structure is a challenge. In this paper, we proposed a new fabrication method of high-precision structure based on an etching resistance layer. The high-precision features were fabricated by photolithography technique, followed by the etching process to transfer the features to the substrate. During this process, the etching uniformity and error lead to the feature distortion. We introduced an etching resistance layer between feature layer and substrate. The etching process will stop when arriving at the resistance layer. Due to the high precision of the plating film, the high-precision structure depth was achieved. In our experiment, we introduced aluminum trioxide as the etching resistance layer. The structures with low depth error of less than 5% were fabricated.

  11. High-precision analysis of the solar twin HIP 100963

    NASA Astrophysics Data System (ADS)

    Yana Galarza, Jhon; Meléndez, Jorge; Ramírez, Ivan; Yong, David; Karakas, Amanda I.; Asplund, Martin; Liu, Fan

    2016-05-01

    Context. HIP 100963 was one of the first solar twins identified. Although some high-precision analyses are available, a comprehensive high-precision study of chemical elements from different nucleosynthetic sources is still lacking from which to obtain potential new insights on planets, stellar evolution, and Galactic chemical evolution (GCE). Aims: We analyze and investigate the origin of the abundance pattern of HIP 100963 in detail, in particular the pattern of the light element Li, the volatile and refractory elements, and heavy elements from the s- and r-processes. Methods: We used the HIRES spectrograph on the Keck I telescope to acquire high-resolution (R ≈ 70 000) spectra with a high signal-to-noise ratio (S/N ≈ 400-650 per pixel) of HIP 100963 and the Sun for a differential abundance analysis. We measured the equivalent widths (EWs) of iron lines to determine the stellar parameters by employing the differential spectroscopic equilibrium. We determined the composition of volatile, refractory, and neutron-capture elements through a differential abundance analysis with respect to the Sun. Results: The stellar parameters we found are Teff = 5818 ± 4 K, log g = 4.49 ± 0.01 dex, vt = 1.03 ± 0.01km s-1, and [Fe/H] = -0.003 ± 0.004 dex. These low errors allow us to compute a precise mass (1.03+0.02-0.01 M⊙) and age (2.0 ± 0.4 Gyr), obtained using Yonsei-Yale isochrones. Using our [Y/Mg] ratio, we have determined an age of 2.1 ± 0.4 Gyr, in agreement with the age computed using isochrones. Our isochronal age also agrees with the age determined from stellar activity (2.4 ± 0.3 Gyr). We study the abundance pattern with condensation temperature (Tcond) taking corrections by the GCE into account. We show that the enhancements of neutron-capture elements are explained by contributions from both the s- and r-process. The lithium abundance follows the tight Li-age correlation seen in other solar twins. Conclusions: We confirm that HIP 100963 is a solar twin

  12. Effects of Tactile Sensitivity on Structural Variability of Digit Forces during Stable Precision Grip

    PubMed Central

    Wei, Na

    2016-01-01

    This study investigated the effects of fingertip tactile sensitivity on the structural variability of thumb and index finger forces during stable precision grip. Thirty right-handed healthy subjects participated in the experiment. Transient perturbation of tactile afferents was achieved by wrapping up the distal pads of the thumb or index finger with transparent polyethylene films. The time-dependent structure of each digit force and the variability of interdigit force correlation were examined by detrended fluctuation analysis (DFA) and detrended cross-correlation analysis (DCCA), respectively. Results showed that the tactile sensitivity affected αDFA of the vertical shear force Fx (F3,239 = 6.814, p < 0.001) and αDCCA of Fx (χ2 = 16.440, p < 0.001). No significant difference was observed in αDFA or αDCCA of the normal forces produced by the thumb or index finger. These results suggested that with blurred tactile sensory inputs the central nervous system might decrease the vertical shear force flexibility and increase the interdigit shear force coupling in order to guarantee a stable grip control of an object against gravity. This study shed light on the feedback and feed-forward strategies involved in digit force control and the role of SA-II afferent fibers in regulation of vertical shear force variability for precision grip. PMID:27847823

  13. High-precision atomic structure measurements in thallium

    NASA Astrophysics Data System (ADS)

    Burkhardt, M. H.; Holmes, C. D.; Uhl, R.; Majumder, P. K.

    2004-05-01

    Using a thallium atomic beam apparatus, we are undertaking a series of laser spectroscopy measurements with the goal of providing precise, independent cross-checks on the accuracy of new calculations of parity nonconservation in thallium(M. Kozlov et al.), Phys Rev. A64, 053107 (2001). In our apparatus, a laser beam interacts transversely with a dense, 2-cm-wide thallium beam and reveals roughly tenfold Doppler narrowing of the absorption profile. Having completed a new 0.4% measurement of the Stark shift within the 378 nm 6P_1/2-7S_1/2 E1 transition, we have now begun to study the weak 1283 nm 6P_1/2-6P_3/2 transition in the atomic beam. We seek to determine both Stark shift components, as well as the various components of the Stark-induced amplitude within this mixed M1/E2 transition. Using these existing laser systems, we have also begun a vapor cell spectroscopy study of the 1301 nm 7S_1/2-7P_1/2 E1 transition by means of a two-step excitation from the ground state. To enhance the visibility of these weak absorption signals, we are employing an FM spectroscopy technique. The demodulated laser transmission spectrum provides a low-noise, zero-background signal, and includes replicas of the absorption spectrum separated by the well-known RF sideband frequency, offering built-in frequency scale calibration.

  14. Interdisciplinary design analysis of a precision spacecraft antenna

    NASA Technical Reports Server (NTRS)

    Steinbach, R. E.; Winegar, S. R.

    1985-01-01

    The Advanced Communications Technology Satellite (ACTS) will operate in the 20/30 GHz range (Ka Band), and will include a multi-beam antenna (MBA) capable of 0.3 degree scanning spot beams with very high beam-to-beam isolation. The antenna Radio Frequency (RF) performance requirements lead to stringent requirements on the antenna reflector surface shape. A prediction of RF performance of a potential flight model antenna reflector operating under space environmental conditions is made using a radiant heat input model (TRASYS), a thermal analyzer (SINDA), a structural model (NASTRAN), and RF far field pattern simulation. Interfacing software has been written to pass thermal model temperature results to the structural model, and structural model thermal deformation results to the RF far field pattern simulation. A complete analysis can be performed in a single computer run, and potential changes in design can be quickly and easily evaluated using this interdisciplinary design analysis tool.

  15. Interdisciplinary design analysis of a precision spacecraft antenna

    NASA Technical Reports Server (NTRS)

    Steinbach, R. E.; Winegar, S. R.

    1985-01-01

    The Advanced Communications Technology Satellite (ACTS) will operate in the 20/30 GHz range (Ka Band), and will include a multi-beam antenna (MBA) capable of 0.3 degree scanning spot beams with very high beam-to-beam isolation. The antenna Radio Frequency (RF) performance requirements lead to stringent requirements on the antenna reflector surface shape. A prediction of RF performance of a potential flight model antenna reflector operating under space environmental conditions is made using a radiant heat input model (TRASYS), a thermal analyzer (SINDA), a structural model (NASTRAN), and RF far field pattern simulation. Interfacing software has been written to pass thermal model temperature results to the structural model, and structural model thermal deformation results to the RF far field pattern simulation. A complete analysis can be performed in a single computer run, and potential changes in design can be quickly and easily evaluated using this interdisciplinary design analysis tool.

  16. Force measurement enabling precise analysis by dynamic force spectroscopy.

    PubMed

    Taninaka, Atsushi; Hirano, Yuuichi; Takeuchi, Osamu; Shigekawa, Hidemi

    2012-01-01

    Dynamic force spectroscopy (DFS) makes it possible to investigate specific interactions between two molecules such as ligand-receptor pairs at the single-molecule level. In the DFS method based on the Bell-Evans model, the unbinding force applied to a molecular bond is increased at a constant rate, and the force required to rupture the molecular bond is measured. By analyzing the relationship between the modal rupture force and the logarithm of the loading rate, microscopic potential barrier landscapes and the lifetimes of bonds can be obtained. However, the results obtained, for example, in the case of streptavidin/biotin complexes, have differed among previous studies and some results have been inconsistent with theoretical predictions. In this study, using an atomic force microscopy technique that enables the precise analysis of molecular interactions on the basis of DFS, we investigated the effect of the sampling rate on DFS analysis. The shape of rupture force histograms, for example, was significantly deformed at a sampling rate of 1 kHz in comparison with that of histograms obtained at 100 kHz, indicating the fundamental importance of ensuring suitable experimental conditions for further advances in the DFS method.

  17. High speed precision motion strategies for lightweight structures

    NASA Technical Reports Server (NTRS)

    Book, Wayne J.

    1987-01-01

    Work during the recording period proceeded along the lines of the proposal, i.e., three aspects of high speed motion planning and control of flexible structures were explored: fine motion control, gross motion planning and control, and automation using light weight arms. In addition, modeling the large manipulator arm to be used in experiments and theory has lead to some contributions in that area. These aspects are reported below. Conference, workshop and journal submissions, and presentations related to this work were seven in number, and are listed. Copies of written papers and abstracts are included.

  18. The study of precision measurement of pelvis spatial structure

    NASA Astrophysics Data System (ADS)

    Ma, Xiang; Ouyang, Jianfei; Qu, Xinghua

    2009-12-01

    Osteometry is fundamental for anthropometry. It provides the key technology and value to the study of palaeoanthropology, medicine, and criminal investigation. The traditional osteometry that has been widely accepted and used since 18th century has no longer met the information demand for modern research and application. It is significant and necessary to create an advanced 3-dimensional osteometry technique for anthropometry. This paper presents a new quick and accurate method to measure human pelvis through mathematical modeling. The pelvis is a complex combination of bones, which consists of three connected parts: hipbones, sacrum, and coccyx. There are over 40 items to be measured for the 1-dimension characteristics. In this paper, a combined measuring technology is developed for pelvis measurement. It uses machine vision systems and a portable measuring arm to obtain key geometry parameters of the pelvis. The mathematics models of the pelvis spatial structure and its parts are created through the process of data collecting, digging, assembling, and modeling. The experiment shows that the proposed technology can meet traditional osteometry and obtain entire 1D geometric parameters of the pelvis, such as maximum breadth and height, diameter of obstetric conjugata, inclination angle, and sakralneigungswinkel, etc. at the same time after modeling. Besides making the measurements above, the proposed technology can measure the geometry characteristics of pelvis and its parts, such as volume, surface area, curvature, and spatial structure, which are almost impossible for traditional technology. The overall measuring error is less than 0.1mm.

  19. The study of precision measurement of pelvis spatial structure

    NASA Astrophysics Data System (ADS)

    Ma, Xiang; Ouyang, Jianfei; Qu, Xinghua

    2010-03-01

    Osteometry is fundamental for anthropometry. It provides the key technology and value to the study of palaeoanthropology, medicine, and criminal investigation. The traditional osteometry that has been widely accepted and used since 18th century has no longer met the information demand for modern research and application. It is significant and necessary to create an advanced 3-dimensional osteometry technique for anthropometry. This paper presents a new quick and accurate method to measure human pelvis through mathematical modeling. The pelvis is a complex combination of bones, which consists of three connected parts: hipbones, sacrum, and coccyx. There are over 40 items to be measured for the 1-dimension characteristics. In this paper, a combined measuring technology is developed for pelvis measurement. It uses machine vision systems and a portable measuring arm to obtain key geometry parameters of the pelvis. The mathematics models of the pelvis spatial structure and its parts are created through the process of data collecting, digging, assembling, and modeling. The experiment shows that the proposed technology can meet traditional osteometry and obtain entire 1D geometric parameters of the pelvis, such as maximum breadth and height, diameter of obstetric conjugata, inclination angle, and sakralneigungswinkel, etc. at the same time after modeling. Besides making the measurements above, the proposed technology can measure the geometry characteristics of pelvis and its parts, such as volume, surface area, curvature, and spatial structure, which are almost impossible for traditional technology. The overall measuring error is less than 0.1mm.

  20. Influence of Structural Flexibility on the Dynamic Precision of a Vehicle-Mounted Equipment System

    DTIC Science & Technology

    2015-05-12

    Paramsothy Jayakumar, Dave Mechergui, Ronald Renke U.S.Army RDECOM TARDEC INFLUENCE OF STRUCTURAL FLEXIBILITY ON THE DYNAMIC PRECISION OF A...with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 12 MAY 2015 2. REPORT TYPE 3. DATES...COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE INFLUENCE OF STRUCTURAL FLEXIBILITY ON THE DYNAMIC PRECISION OF A VEHICLE-MOUNTED EQUIPMENT

  1. Precision synthesis, structure and function of helical polymers

    PubMed Central

    OKAMOTO, Yoshio

    2015-01-01

    Helical structures are chiral, which means that if we can synthesize a polymer having a stable one-handed helicity, the polymer is optically active. In 1979, we succeeded in the synthesis of a one-handed helical polymer from an optically inactive achiral monomer, triphenylmethyl methacrylate (TrMA). This is the first example of the asymmetric synthesis of an optically active one-handed helical polymer. The polymer (PTrMA) exhibited an unexpected high chiral recognition ability and afforded a practically useful chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) by coating it on silica gel. In addition, we also succeeded in the development of very useful CSPs for HPLC using the phenylcarbamate derivatives of polysaccharides, cellulose and amylose. These CSPs can efficiently resolve a broad range of chiral compounds, and have been used all over the world for separating and analyzing chiral compounds. PMID:26062738

  2. Precision synthesis, structure and function of helical polymers.

    PubMed

    Okamoto, Yoshio

    2015-01-01

    Helical structures are chiral, which means that if we can synthesize a polymer having a stable one-handed helicity, the polymer is optically active. In 1979, we succeeded in the synthesis of a one-handed helical polymer from an optically inactive achiral monomer, triphenylmethyl methacrylate (TrMA). This is the first example of the asymmetric synthesis of an optically active one-handed helical polymer. The polymer (PTrMA) exhibited an unexpected high chiral recognition ability and afforded a practically useful chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) by coating it on silica gel. In addition, we also succeeded in the development of very useful CSPs for HPLC using the phenylcarbamate derivatives of polysaccharides, cellulose and amylose. These CSPs can efficiently resolve a broad range of chiral compounds, and have been used all over the world for separating and analyzing chiral compounds.

  3. Spectral analysis of GPS precise point positioning time series

    NASA Astrophysics Data System (ADS)

    Selle, C.; Desai, S.; Garcia Fernandez, M.; Sibois, A.

    2014-12-01

    This paper presents the results from performing spectral analysis on GPS positioning time series obtained from precise point positioning (PPP). The goal of this work was to evaluate the impact of different choices of processing strategies and models on GPS-based PPP. We studied the spectra of station positions, examined overall noise levels and identified the presence of spurious periodic signals. Testing various processing options allowed us to assess their effect on station position estimates. With the Jet Propulsion Laboratory's contribution to the second reprocessing campaign of the International GNSS Service (IGS) as our reference source for input orbits and clocks, we also considered the effects of using different orbit and clock products. This included products from the previous reprocessing campaign, which were fixed in the IGS05 reference frame, while recent products use the IGS08 frame. Of particular importance are our results from assessing the impact on the station position time series from the single-receiver ambiguity resolution capability offered by JPL's reprocessing campaigns. Furthermore, our tests raise the possibility of distinguishing between PPP processing settings, input orbits and clocks, and station data and location-dependent effects as causes of these features.

  4. Development of precision machining and inspection technology for structural ceramics

    SciTech Connect

    Barkman, W.E.

    1997-03-06

    Finish machining operations contribute the majority of the costs associated with fabricating high quality ceramic products. These components are typically used in harsh environments such as diesel engines, the defense industry, and automotive applications. The required finishing operations involve a variety of technology areas including process controls, process analysis, product certification, etc. and are not limited only to component grinding methods. The broad range of manufacturing problem solving expertise available in Oak Ridge provided resources that were far beyond what is available to the Coors manufacturing sites. Coors contributed equipment, such as the computer controls and part handling mechanisms associated with a state-of-the-art inspection machine plus operation-specific experience base. In addition, addressing these challenging tasks enabled Oak Ridge personnel to maintain familarity with rapidly advancing technologies, such as those associated with machine vision equipment, process monitoring techniques, and computer control systems.

  5. Precision analysis of passive BD aided pseudolites positioning system

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoming; Zhao, Yan

    2007-11-01

    In recent years BD (BeiDou positioning system), an active satellite navigation system, has been widely applied in geodetic survey, precise engineering survey and GNC (guide, navigation and control system) of weapons because of its reliability and availability. However, it has several problems on the accuracy, anti-interference and active-positioning. A passive BD aided pseudolites positioning system is introduced in details in this paper. The configuration and the operating principle of system are presented. In analyzing the precision of location, one of the crucial aspects to be studied is how to determine the arrangement of the pseudolites to get the good GDOP, which is discussed in the different arrangements of the pseudolites in this paper. The simulation results show that the VDOP (vertical dilution of precision) of BD is improved due to introducing the pseudolites. The experiments indicate the validity of the methods and the improvement of the positioning precision in the BD aided pseudolite system.

  6. 3-D uncertainty-based topographic change detection with structure-from-motion photogrammetry and precision maps

    NASA Astrophysics Data System (ADS)

    James, Mike R.; Robson, Stuart; Smith, Mark W.

    2017-04-01

    Structure-from-motion (SfM) software greatly facilitates the generation of 3-D surface models from photographs, but doesn't provide the detailed error metrics that are characteristic of rigorous photogrammetry. Here, we present a novel approach to generate maps of 3-D survey precision which describe the spatial variability in 3-D photogrammetric and georeferencing precision across surveys. Such maps then enable confidence-bounded quantification of 3-D topographic change that, for the first time, specifically account for the precision characteristics of photo-based surveys. Precision maps for surveys georeferenced either directly using camera positions or by ground control, illustrate the spatial variability in precision that is associated with the relative influences of photogrammetric (e.g. image network geometry, tie point quality) and georeferencing considerations. For common SfM-based software (which does not provide precision estimates directly), precision maps can be generated using a Monte Carlo procedure. Confidence-bounded full 3-D change detection between repeat surveys with associated precision maps, is then derived through adapting a state-of-the-art point-cloud comparison (M3C2; Lague, et al., 2013). We demonstrate the approach using annual aerial SfM surveys of an eroding badland, benchmarked against TLS data for validation. 3-D precision maps enable more probable erosion patterns to be identified than existing analyses. If precision is limited by weak georeferencing (e.g. using direct georeferencing with camera positions of multi-metre precision, such as from a consumer UAV), then overall survey precision scales as n-1 /2 of the control precision (n = number of images). However, direct georeferencing results from SfM software (PhotoScan) were not consistent with those from rigorous photogrammetric analysis. Our method not only enables confidence-bounded 3-D change detection and uncertainty-based DEM processing, but also provides covariance

  7. Multilevel micro-structuring of glassy carbon molds for precision glass molding

    NASA Astrophysics Data System (ADS)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans Peter; Plöger, Sven; Hermerschmidt, Andreas

    2015-09-01

    Replication techniques for diffractive optical elements (DOEs) in soft materials such as plastic injection molding are state of the art. For precision glass molding in glasses with high transition temperatures, molds with extreme thermal resistivity, low chemical reactivity and high mechanical strength are needed. Glassy Carbon can be operated up to 2000°C making it possible to mold almost all glasses including Fused Silica with a transition temperatures above 1060°C. For the structuring of Glassy Carbon wafers photolithography and a RIE process is used. We have developed a process using Si as a hard mask material. If the flow rates of the etching gases O2 and SF6 are chosen properly, high selectivity of GC to Si 19:1 can be achieved, which provides excellent conditions to realize high resolution elements with feature size down to 1 micron and fulfills requirements for optical applications. We fabricated several multilevel GC molds with 8 levels of structuring. Two different optical functionalities were implemented: 6x6 array beamsplitter and 1x4 linear beamsplitter. The molds were applied for precision glass molding of a low Tg glass L-BAL 42 (from Ohara) with a transition temperature of 565°C. Their optical performance was measured. A more detailed analysis of the impact of mold fabrication defects on optical performance is done. Rigorous coupled wave analysis simulations are performed, where we included fabrication constrains such as duty cycle, edge depth errors, wall verticality and misalignment errors. We will compare the results with the design specifications and discuss the influence of fabrication errors introduced during the different process steps.

  8. Toward Repurposing Metformin as a Precision Anti-Cancer Therapy Using Structural Systems Pharmacology

    PubMed Central

    Hart, Thomas; Dider, Shihab; Han, Weiwei; Xu, Hua; Zhao, Zhongming; Xie, Lei

    2016-01-01

    Metformin, a drug prescribed to treat type-2 diabetes, exhibits anti-cancer effects in a portion of patients, but the direct molecular and genetic interactions leading to this pleiotropic effect have not yet been fully explored. To repurpose metformin as a precision anti-cancer therapy, we have developed a novel structural systems pharmacology approach to elucidate metformin’s molecular basis and genetic biomarkers of action. We integrated structural proteome-scale drug target identification with network biology analysis by combining structural genomic, functional genomic, and interactomic data. Through searching the human structural proteome, we identified twenty putative metformin binding targets and their interaction models. We experimentally verified the interactions between metformin and our top-ranked kinase targets. Notably, kinases, particularly SGK1 and EGFR were identified as key molecular targets of metformin. Subsequently, we linked these putative binding targets to genes that do not directly bind to metformin but whose expressions are altered by metformin through protein-protein interactions, and identified network biomarkers of phenotypic response of metformin. The molecular targets and the key nodes in genetic networks are largely consistent with the existing experimental evidence. Their interactions can be affected by the observed cancer mutations. This study will shed new light into repurposing metformin for safe, effective, personalized therapies. PMID:26841718

  9. System identification of the JPL micro-precision interferometer truss - Test-analysis reconciliation

    NASA Technical Reports Server (NTRS)

    Red-Horse, J. R.; Marek, E. L.; Levine-West, M.

    1993-01-01

    The JPL Micro-Precision Interferometer (MPI) is a testbed for studying the use of control-structure interaction technology in the design of space-based interferometers. A layered control architecture will be employed to regulate the interferometer optical system to tolerances in the nanometer range. An important aspect of designing and implementing the control schemes for such a system is the need for high fidelity, test-verified analytical structural models. This paper focuses on one aspect of the effort to produce such a model for the MPI structure, test-analysis model reconciliation. Pretest analysis, modal testing, and model refinement results are summarized for a series of tests at both the component and full system levels.

  10. The Effects of Random Vibration on the Dimensional Stability of Precision Structures

    NASA Astrophysics Data System (ADS)

    Edeson, Ruben L.; Aglietti, Guglielmo S.; Tatnall, Adrian R.

    2012-07-01

    Precision structures for space-based optical systems are typically subjected to brief periods of random vibration during the launch and ground testing phases. Such events pose a potential threat to the dimensional stability of such structures, which may be required to maintain positional tolerances on large optics in the low 10s of microns to meet optical performance requirements. Whilst there is an abundance of information in the literature on structural instability caused by hygrothermal cycling, there appears to have been little work done on the effects of random vibration. This issue has recently been addressed at RAL with a series of tests aimed at characterizing the behavior of dimensional instability in structures for high-resolution Earth-imaging cameras subject to random vibration. Firstly, a breadboard model of a typical “conventional” CFRP-based optical payload structure was produced and subjected to a range of environmental tests. The effects of random vibration were compared to those of other environmental stressors (such as thermal vacuum testing) and found to be significant. Next, controlled tests were performed on specific structural areas in order to assess the specific contributions of each area to overall instability. These tests made use of novel test setups and metrology techniques to assess the dimensional stability response of material samples and bolted joints to random vibration exposure. The tests were able to measure dimensional instability, characterize it over a series of tests of increasing vibration levels, and assess variability in results between identical samples. Finally, a predictive technique using a Finite Element Model with nonlinear kinematic hardening was produced. A time domain solution was obtained, using an analogy to Miner’s Rule to determine load cycle amplitudes. This model correlated reasonably well with test results. This paper presents this program of work, and the results. It also proposes ways to minimize

  11. Causal diagrams and multivariate analysis II: precision work.

    PubMed

    Jupiter, Daniel C

    2014-01-01

    In this Investigators' Corner, I continue my discussion of when and why we researchers should include variables in multivariate regression. My examination focuses on studies comparing treatment groups and situations for which we can either exclude variables from multivariate analyses or include them for reasons of precision. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Precise rainbow trapping for low-frequency acoustic waves with micro Mie resonance-based structures

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Yuan, Baoguo; Cheng, Ying; Liu, Xiaojun

    2016-02-01

    We have realized the acoustic rainbow trapping in the low frequency region (200-500 Hz) through micro Mie resonance-based structures. The structure has eight channels with a high refractive index obtained by coiling space, that can excite strong interactions with incident waves and support various orders of multipoles due to the Mie resonances of the microstructure. By utilizing the structure, the precise spatial modulation of the acoustic wave is demonstrated both theoretically and experimentally. The effect of trapping broadband acoustic waves and spatially separating different frequency components are ascribed to the monopolar Mie resonances of the structures. The trapping frequency is derived and the trapping positions can be tuned arbitrarily. With enhanced wave-structure interactions and tailored frequency responses, such micro structures show precise spectral-spatial control of acoustic waves and open a diverse venue for high performance acoustic wave detection, sensing, filtering, and a nondestructive test.

  13. High-precision investigation of nanorod and nanosphere topological structures for nanoelectronic issues by means of atomic-force microscopy

    NASA Astrophysics Data System (ADS)

    Zhukov, M. V.; Lysak, V. V.; Mukhin, I. S.; Golubok, A. O.

    2016-08-01

    Fabrication and study of specialized single nanowhisker probes are performed for high-precision investigation of elements such as nanospheres and nanorods using the atomic force microscopy. It was found that single nanowhisker probe significantly increases the resolution and contrast of images obtained in the semi-contact mode. Furthermore, the roughness analysis and adhesion forces are investigated in contact mode to comprehensively characterize properties of nanospherical and nanorod electronic structures.

  14. Local precision nets for monitoring movements of faults and large engineering structures

    NASA Technical Reports Server (NTRS)

    Henneberg, H. G.

    1978-01-01

    Along Bocono Fault were installed local high precision geodetic nets to observe the possible horizontal crustal deformations and movements. In the fault area there are few big structures which are also included in the mentioned investigation. In the near future, measurements shall be extended to other sites of Bocono Fault and also to the El Pilar Fault. In the same way and by similar methods high precision geodetic nets are applied in Venezuela to observe the behavior of big structures, as bridges and large dams and of earth surface deformations due to industrial activities.

  15. Laser - Polarized HE-3 Target Used for a Precision Measurement of the Neutron Spin Structure

    SciTech Connect

    Romalis, M

    2003-11-05

    This thesis describes a precision measurement of the deep inelastic neutron spin structure function g{sub 1}{sup n}(x). The main motivation for the experiment is a test of the Bjorken sum rule. Because of smaller statistical errors and broader kinematic coverage than in previous experiments, we are able to study in detail the behavior of the spin structure function g{sub 1}{sup n}(x) for low values of the Bjorken scaling variable x. We find that it has a strongly divergent behavior, in contradiction to the naive predictions of the Regge theory. This calls into question the methods commonly used for extrapolation of g{sub 1}{sup n}(x) to x = 0. The difference between the proton and the neutron spin structure functions is less divergent at low x, so a test of the Bjorken sum rule is possible. We confirm the sum rule with an accuracy of 8%. The experiment was performed at SLAC using a 50 GeV polarized electron beam and a polarized {sup 3}He target. In this thesis the polarized target is described in detail. We used the technique of Rb optical pumping and Rb-He spin exchange to polarize the {sup 3}He. Because of a novel mechanical design our target had the smallest dilution ever achieved for a high density gas target. Since this is a precision measurement, particular efforts were made to reduce the systematic errors due to the uncertainty in the target parameters. Most important parameters were measured by more than one method. We implemented novel techniques for measuring the thickness of the glass windows of the target, the {sup 3}He density, and the polarization. In particular, one of the methods for measuring the gas density relied on the broadening of the Rb optical absorption lines by collisions with {sup 3}He atoms. The calibration of this technique resulted in the most precise measurements of the pressure broadening parameters for {sup 3}He as well as several other gases, which are described in an Appendix. The polarization of the {sup 3}He was also measured by

  16. Improve Radial Velocity Precision with Better Data Analysis Tools

    NASA Astrophysics Data System (ADS)

    Xuesong Wang, Sharon; Wright, Jason; Zhao, Ming

    2015-12-01

    The synergy between Kepler and the ground-based radial velocity (RV) surveys have made numerous discoveries of low-mass exoplanets, opening the age of Earth analogs. However, Earth analogs such as Kepler 452-b require a much higher RV precision ( ~ 10 cm/s) than the achievable with current instruments (~ 1 m/s) and understanding of stellar photosphere. This presentation will cover some of the instrumental and data issues that are currently hindering us from achieving the sub 1 m/s precision, as well as remedies and ways forward with future RV instruments. Highlights of our work include: (1) how telluric contamination affects RV precision and how to "telluric-proof" a Doppler pipeline; (2) how errors in the deconvolved stellar reference spectrum can mimic the signal of a super-Earth on a ~1 year orbit; (3) the battle with imperfections in the iodine reference spectra and how an ultra-high resolution (R ~ 500,000) echelle spectrum can help; (4) and a new RV extraction code in Python which incorporates MCMC and Gaussian Processes. This research is based on radial velocity data taken with iodine cell calibrators using Keck/HIRES and HET/HRS.

  17. Precision of age estimates from different ageing structures in selected freshwater teleosts.

    PubMed

    Khan, Shahista; Khan, M Afzal; Miyan, Kaish; Lone, Faisal Ahmad

    2015-03-01

    The present study was undertaken with a view to compare the precision of age readings obtained from different ageing structures of some important freshwater teleosts viz., Hypophthalmichthys molitrix, Mastacembelus armatus and Ompok pabda. Standard procedures were followed to study the ageing structures. Based on the highest percent agreement and lowest average percentage of error and coefficient of variation values, precise age estimates were exhibited by opercular bones in H. molitrix and vertebrae in the remaining two fish, M. armatus and O. pabda. When precise age estimates were compared among the age estimates of other ageing structures, highest percent agreement and lowest average percent error and coefficient of variation values were exhibited by vertebrae (versus opercular bones) in H. molitrix and opercular bones (versus vertebrae) in both M. armatus and O. pabda. When mean age estimates from different ageing structures were compared, vertebrae and opercular bones exhibited comparable values in H. molitrix. In M. armatus, mean values of precise age estimates from vertebrae were significantly different from the values of other ageing structures. However, in O. pabda, vertebrae as well as opercular bones showed insignificantly different age readings.

  18. Nonlinear Structural Analysis

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Nonlinear structural analysis techniques for engine structures and components are addressed. The finite element method and boundary element method are discussed in terms of stress and structural analyses of shells, plates, and laminates.

  19. Displacement sensor with controlled measuring force and its error analysis and precision verification

    NASA Astrophysics Data System (ADS)

    Yang, Liangen; Wang, Xuanze; Lv, Wei

    2010-12-01

    A displacement sensor with controlled measuring force and its error analysis and precision verification are discussed in this paper. The displacement sensor consists of an electric induction transducer with high resolution and a voice coil motor (VCM). The measuring principles, structure, method enlarging measuring range, signal process of the sensor are discussed. The main error sources such as parallelism error and incline of framework by unequal length of leaf springs, rigidity of measuring rods, shape error of stylus, friction between iron core and other parts, damping of leaf springs, variation of voltage, linearity of induction transducer, resolution and stability are analyzed. A measuring system for surface topography with large measuring range is constructed based on the displacement sensor and 2D moving platform. Measuring precision and stability of the measuring system is verified. Measuring force of the sensor in measurement process of surface topography can be controlled at μN level and hardly changes. It has been used in measurement of bearing ball, bullet mark, etc. It has measuring range up to 2mm and precision of nm level.

  20. Displacement sensor with controlled measuring force and its error analysis and precision verification

    NASA Astrophysics Data System (ADS)

    Yang, Liangen; Wang, Xuanze; Lv, Wei

    2011-05-01

    A displacement sensor with controlled measuring force and its error analysis and precision verification are discussed in this paper. The displacement sensor consists of an electric induction transducer with high resolution and a voice coil motor (VCM). The measuring principles, structure, method enlarging measuring range, signal process of the sensor are discussed. The main error sources such as parallelism error and incline of framework by unequal length of leaf springs, rigidity of measuring rods, shape error of stylus, friction between iron core and other parts, damping of leaf springs, variation of voltage, linearity of induction transducer, resolution and stability are analyzed. A measuring system for surface topography with large measuring range is constructed based on the displacement sensor and 2D moving platform. Measuring precision and stability of the measuring system is verified. Measuring force of the sensor in measurement process of surface topography can be controlled at μN level and hardly changes. It has been used in measurement of bearing ball, bullet mark, etc. It has measuring range up to 2mm and precision of nm level.

  1. High-precision optical systems with inexpensive hardware: a unified alignment and structural design approach

    NASA Astrophysics Data System (ADS)

    Winrow, Edward G.; Chavez, Victor H.

    2011-09-01

    High-precision opto-mechanical structures have historically been plagued by high costs for both hardware and the associated alignment and assembly process. This problem is especially true for space applications where only a few production units are produced. A methodology for optical alignment and optical structure design is presented which shifts the mechanism of maintaining precision from tightly toleranced, machined flight hardware to reusable, modular tooling. Using the proposed methodology, optical alignment error sources are reduced by the direct alignment of optics through their surface retroreflections (pips) as seen through a theodolite. Optical alignment adjustments are actualized through motorized, sub-micron precision actuators in 5 degrees of freedom. Optical structure hardware costs are reduced through the use of simple shapes (tubes, plates) and repeated components. This approach produces significantly cheaper hardware and more efficient assembly without sacrificing alignment precision or optical structure stability. The design, alignment plan and assembly of a 4" aperture, carbon fiber composite, Schmidt-Cassegrain concept telescope is presented.

  2. Development of an active member using piezoelectric and electrostrictive actuation for control of precision structures

    NASA Technical Reports Server (NTRS)

    Anderson, E. H.; Moore, D. M.; Fanson, J. L.; Ealey, M. A.

    1990-01-01

    The design and development of a zero stiction active member containing piezoelectric and electrostrictive actuator motors is presented. The active member is intended for use in submicron control of structures. Experimental results are shown which illustrate actuator and device characteristics relevant to precision control applications.

  3. Precision of hard structures used to estimate age of mountain Whitefish (Prosopium williamsoni)

    USGS Publications Warehouse

    Watkins, Carson J.; Ross, Tyler J.; Hardy, Ryan S.; Quist, Michael

    2015-01-01

    The mountain whitefish (Prosopium williamsoni) is a widely distributed salmonid in western North America that has decreased in abundance over portions of its distribution due to anthropogenic disturbances. In this investigation, we examined precision of age estimates derived from scales, pectoral fin rays, and sagittal otoliths from 167 mountain whitefish. Otoliths and pectoral fin rays were mounted in epoxy and cross-sectioned before examination. Scales were pressed onto acetate slides and resulting impressions were examined. Between-reader precision (i.e., between 2 readers), between-reader variability, and reader confidence ratings were compared among hard structures. Coefficient of variation (CV) in age estimates was lowest and percentage of exact agreement (PA-0) was highest for scales (CV = 5.9; PA-0 = 70%) compared to pectoral fin rays (CV =11.0; PA-0 = 58%) and otoliths (CV = 12.3; PA-0 = 55%). Median confidence ratings were significantly different (P ≤ 0.05) among all structures, with scales having the highest median confidence. Reader confidence decreased with fish age for scales and pectoral fin rays, but reader confidence increased with fish age for otoliths. In general, age estimates were more precise and reader confidence was higher for scales compared to pectoral fin rays and otoliths. This research will help fisheries biologists in selecting the most appropriate hard structure to use for future age and growth studies on mountain whitefish. In turn, selection of the most precise hard structure will lead to better estimates of dynamic rate functions.

  4. Analysis of precision in chemical oscillators: implications for circadian clocks

    NASA Astrophysics Data System (ADS)

    d'Eysmond, Thomas; De Simone, Alessandro; Naef, Felix

    2013-10-01

    Biochemical reaction networks often exhibit spontaneous self-sustained oscillations. An example is the circadian oscillator that lies at the heart of daily rhythms in behavior and physiology in most organisms including humans. While the period of these oscillators evolved so that it resonates with the 24 h daily environmental cycles, the precision of the oscillator (quantified via the Q factor) is another relevant property of these cell-autonomous oscillators. Since this quantity can be measured in individual cells, it is of interest to better understand how this property behaves across mathematical models of these oscillators. Current theoretical schemes for computing the Q factors show limitations for both high-dimensional models and in the vicinity of Hopf bifurcations. Here, we derive low-noise approximations that lead to numerically stable schemes also in high-dimensional models. In addition, we generalize normal form reductions that are appropriate near Hopf bifurcations. Applying our approximations to two models of circadian clocks, we show that while the low-noise regime is faithfully recapitulated, increasing the level of noise leads to species-dependent precision. We emphasize that subcomponents of the oscillator gradually decouple from the core oscillator as noise increases, which allows us to identify the subnetworks responsible for robust rhythms.

  5. The influence of calculated phase shifts on the precision and accuracy of ARPEFS-derived structural parameters

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Hussain, Z.; Shirley, D. A.

    1993-04-01

    The influence of theoretical atomic scattering phase shifts calculated by different methods in the analysis in the analysis of angle-resolved photoemission extended fine structure (ARPEFS) data for structural determination of the c(2×2)S/Ni(001) surface was examined, with the goal of assessing both the precision and accuracy of derived structural parameters. It was found that the values of the SNi bond length obtained from the ARPEFS data analysis with different calculated atomic scattering phase shifts all fall within a total range of 0.02 Å (± 0.01 Å). This result is also in excellent agreement with the currently accepted values obtained from low-energy electron diffraction (LEED) and surface extended X-ray absorption fine structure (SEXAFS), i.e. 2.19-2.20 rA. We conclude that this ARPEFS-derived structural parameter is relatively insensitive to the choice of theoretical atomic scattering phase shifts, and is both precise and accurate.

  6. Gravity sag of sandwich panel assemblies as applied to precision cathode strip chamber structural design

    SciTech Connect

    Horvath, J.

    1993-09-16

    The relationship between gravity sag of a precision cathode strip chamber and its sandwich panel structural design is explored parametrically. An algorithm for estimating the dominant component of gravity sag is defined. Graphs of normalized gravity sag as a function of gap frame width and material, sandwich core edge filler width and material, panel skin thickness, gap height, and support location are calculated using the gravity sag algorithm. The structural importance of the sandwich-to-sandwich ``gap frame`` connection is explained.

  7. Egg white coagulum: a precisely tailorable membrane for biomimetic multilevel structured nanomaterials

    PubMed Central

    Wang, Xiaolei; Zhu, Hui; Liu, Xuexia; Yang, Fan; Yang, Xiurong

    2013-01-01

    For the first time, hen egg white coagulum was utilized as a surface modification agent for biomimetic multilevel structured nanomaterials (BMSN). By using a straightforward thermal control process, hen egg white can be coagulated in a precisely tailored manner, which is specifically adapted to the morphology of BMSN. Consequently, the structural stability, hydrophobicity and biocompatibility of BMSN can be improved significantly and simultaneously within one hour. Meanwhile, their initial structure-related function can be maintained with higher reliability. These advantages offer an incentive to use egg white coagulum as a facile, precise, quick and much cost-effective alternative to the conventional stabilization materials, such as hot melt adhesive, chitosan and polydopamine. PMID:23492932

  8. Precise trace rare earth analysis by radiochemical neutron activation

    SciTech Connect

    Laul, J.C.; Lepel, E.A.; Weimer, W.C.; Wogman, N.A.

    1981-06-01

    A rare earth group separation scheme followed by normal Ge(Li), low energy photon detector (LEPD), and Ge(Li)-NaI(Tl) coincidence-noncoincidence spectrometry significantly enhances the detection sensitivity of individual rare earth elements (REE) at or below the ppB level. Based on the selected ..gamma..-ray energies, normal Ge(Li) counting is favored for /sup 140/La, /sup 170/Tb, and /sup 169/Yb; LEPD is favored for low ..gamma..-ray energies of /sup 147/Nd, /sup 153/Sm, /sup 166/Ho, and /sup 169/Yb; and noncoincidence counting is favored for /sup 141/Ce, /sup 143/Ce, /sup 142/Pr, /sup 153/Sm, /sup 171/Er, and /sup 175/Yb. The detection of radionuclides /sup 152m/Eu, /sup 159/Gd, and /sup 177/Lu is equally sensitive by normal Ge(Li) and noncoincidence counting; /sup 152/Eu is equally sensitive by LEPD and normal Ge(Li); and /sup 153/Gd and /sup 170/Tm is equally favored by all the counting modes. Overall, noncoincidence counting is favored for most of the REE. Precise measurements of the REE were made in geological and biological standards.

  9. Precision Analysis of Visual Odometry Based on Disparity Changing

    NASA Astrophysics Data System (ADS)

    Fu, C. Y.; Tsay, J. R.

    2017-08-01

    This thesis aims to analyze the precision of Position and orientation of cameras on Mobile Mapping System (MMS) determined by disparity based VO (DBVO). Dual forwards taken cameras on MMS are applied to obtain a sequence of stereo pairs. The Interior Orientation Parameters (IOPs) and Relative Orientation Parameters (ROPs) are derived in advance. The pose estimation is achieved by DBVO without additional control data. The procedure of DBVO consists of four steps. First up, keypoint detection and matching is conducted to obtain tie points in consecutive images. Then, image rectification is implemented to transform tie points into epipolar image space. Next, parallax equation is applied to estimate the 3D coordinates of interest points in epipolar image 3D space. Since their image points have different disparity in neighboring stereo pairs, the 3D coordinates of interest points in neighboring pairs are different as well. Finally, 3D conformal transformation is employed to derive the transformation parameters between neighboring pairs according to changing of coordinates of interest points. The posteriori STDs are adopted to assess the quality of transformation. Besides, check data of ground trajectory derived by photo triangulation are applied to evaluate the result. The relative errors of horizontal and vertical translations derived by DBVO are 2 % and 3 % in non-viewing direction. However, the translation in viewing direction and three rotation angles derived by DBVO have significant systematic errors about 1 m, 3°, 3° and 10° respectively. The influence of error propagation is not significant according to the chart of error distance ratio. In open area, the trajectory of INS/GPS is similar to ground truth, while the trajectory derived by DBVO has 44 % relative error. In residential district, the trajectory derived by INS/GPS has drift error about 2 m, while the relative error of the trajectory derived by DBVO decreases to 38

  10. Determining Sample Sizes for Precise Contrast Analysis with Heterogeneous Variances

    ERIC Educational Resources Information Center

    Jan, Show-Li; Shieh, Gwowen

    2014-01-01

    The analysis of variance (ANOVA) is one of the most frequently used statistical analyses in practical applications. Accordingly, the single and multiple comparison procedures are frequently applied to assess the differences among mean effects. However, the underlying assumption of homogeneous variances may not always be tenable. This study…

  11. Precise design-based defect characterization and root cause analysis

    NASA Astrophysics Data System (ADS)

    Xie, Qian; Venkatachalam, Panneerselvam; Lee, Julie; Chen, Zhijin; Zafar, Khurram

    2017-03-01

    that human operators will typically miss), to obtain the exact defect location on design, to compare all defective patterns thus detected against a library of known patterns, and to classify all defective patterns as either new or known. By applying the computer to these tasks, we automate the entire process from defective pattern identification to pattern classification with high precision, and we perform this operation en masse during R & D, ramp, and volume production. By adopting the methodology, whenever a specific weak pattern is identified, we are able to run a series of characterization operations to ultimately arrive at the root cause. These characterization operations can include (a) searching all pre-existing Review SEM images for the presence of the specific weak pattern to determine whether there is any spatial (within die or within wafer) or temporal (within any particular date range, before or after a mask revision, etc.) correlation and (b) understanding the failure rate of the specific weak pattern to prioritize the urgency of the problem, (c) comparing the weak pattern against an OPC (Optical Procimity Correction) Verification report or a PWQ (Process Window Qualification)/FEM (Focus Exposure Matrix) result to assess the likelihood of it being a litho-sensitive pattern, etc. After resolving the specific weak pattern, we will categorize it as known pattern, and the engineer will move forward with discovering new weak patterns.

  12. An advanced precision analysis of the SM vacuum stability

    NASA Astrophysics Data System (ADS)

    Bednyakov, A. V.

    2017-09-01

    The talk is devoted to the problem of stability of the Standard Model vacuum. The effective potential for the Higgs field, which can potentialy exhibit additional, deeper minimum, is considered as a convenient tool for addressing the problem. Different methods and approximations used to calculate the potential are considered. Special attention is paid to the renomalization-group approach that allows one to carry out three-loop analysis of the problem. By means of an explicit gauge-independent procedure the absolute stability bounds on the observed Higgs and top-quark masses are derived. The importance of high-order corrections is demonstrated. In addition, potential metastablity of the SM is discussed together with modifications of the analysis due to some New Physics.

  13. Resources for Precision Analysis of Human Breast Cancer

    DTIC Science & Technology

    2000-08-01

    immunohistochemistry samples) in parallel and us- cases the predicted variant proteins have loss or dis - ing the superfect transfection system (Qiagen, CA) ruption...DCC exists, dis - crepant results occur in a proportion of tumors [8, 9, Western blot analysis 11-13]. These discrepancies are not only between IHA and...breast of a C-terminally truncated ER variant and that dis - tumors by DCC and IHA using both ’N-terminal’ cordant IHA results in tumors using

  14. A grid for a precise analysis of daily activities.

    PubMed

    Wojtasik, V; Olivier, C; Lekeu, F; Quittre, A; Adam, S; Salmon, E

    2010-01-01

    Assessment of daily living activities is essential in patients with Alzheimer's disease. Most current tools quantitatively assess overall ability but provide little qualitative information on individual difficulties. Only a few tools allow therapists to evaluate stereotyped activities and record different types of errors. We capitalised on the Kitchen Activity Assessment to design a widely applicable analysis grid that provides both qualitative and quantitative data on activity performance. A cooking activity was videotaped in 15 patients with dementia and assessed according to the different steps in the execution of the task. The evaluations obtained with our grid showed good correlations between raters, between versions of the grid and between sessions. Moreover, the degree of independence obtained with our analysis of the task correlated with the Kitchen Activity Assessment score and with a global score of cognitive functioning. We conclude that assessment of a daily living activity with this analysis grid is reproducible and relatively independent of the therapist, and thus provides quantitative and qualitative information useful for both evaluating and caring for demented patients.

  15. Precision Measurements of the Neutron Spin Structure at Jefferson Lab Hall A

    SciTech Connect

    Xiaochao Zheng

    2004-09-01

    The authors present here recent progress on the experimental study of the neutron spin structure at Jefferson Lab Hall A. They focus on two precision experiments. The physics motivation and the experimental setup will be described first. Then they present results for the neutron spin asymmetry A{sub 1}{sup n} and results for spin-flavor decomposition of the nucleon spin in the valence quark region, and preliminary results for the neutron spin structure function g{sub 2}{sup n} at low Q{sup 2}.

  16. Accuracy and precision of regional multiharmonic Fourier analysis of gated blood-pool images.

    PubMed

    Machac, J; Horowitz, S F; Broder, D; Goldsmith, S J

    1984-12-01

    In order to estimate the precision and accuracy of parameters derived from segmental multiharmonic Fourier analysis of gated blood-pool images, a Monte Carlo computer noise simulation was tested on five sample regional time-activity curves. The first three Fourier harmonics were retained and the precision and accuracy of parameters of ventricular function were calculated, varying the ejection fraction, segment size, and framing rate. Precision improved with higher ejection fraction, higher counts per frame, or higher framing rate. There was no change in precision as the framing rate changed at fixed total counts. Accuracy changed little with changing framing rate. Thus, for segmental analysis there is no advantage to using a higher framing rate. Regions five or more pixels in size are recommended for reliable results. This study provides useful information for the optimization of acquisition and processing conditions for regional gated blood-pool analysis.

  17. SLR precision analysis for LAGEOS I and II

    NASA Astrophysics Data System (ADS)

    Kizilsu, Gaye; Sahin, Muhammed

    2000-10-01

    This paper deals with the problem of properly weighting satellite observations which are non-uniform in quality. The technique, the variance component estimation method developed by Helmert, was first applied to the 1987 LAGEOS I SLR data by Sahin et al. (1992). This paper investigates the performance of the globally distributed SLR stations using the Helmert type variance component estimation. As well as LAGEOS I data, LAGEOS II data were analysed, in order to compare with the previously analysed 1987 LAGEOS I data. The LAGEOS I and II data used in this research were obtained from the NASA Crustal Dynamics Data Information System (CDDIS), which archives data acquired from stations operated by NASA and by other U.S. and international organizations. The data covers the years 1994, 1995 and 1996. The analysis is based on "full-rate" laser observations, which consist of hundreds to thousands of ranges per satellite pass. The software used is based on the SATAN package (SATellite ANalysis) developed at the Royal Greenwich Observatory in the UK.

  18. Precise and Scalable Static Program Analysis of NASA Flight Software

    NASA Technical Reports Server (NTRS)

    Brat, G.; Venet, A.

    2005-01-01

    Recent NASA mission failures (e.g., Mars Polar Lander and Mars Orbiter) illustrate the importance of having an efficient verification and validation process for such systems. One software error, as simple as it may be, can cause the loss of an expensive mission, or lead to budget overruns and crunched schedules. Unfortunately, traditional verification methods cannot guarantee the absence of errors in software systems. Therefore, we have developed the CGS static program analysis tool, which can exhaustively analyze large C programs. CGS analyzes the source code and identifies statements in which arrays are accessed out of bounds, or, pointers are used outside the memory region they should address. This paper gives a high-level description of CGS and its theoretical foundations. It also reports on the use of CGS on real NASA software systems used in Mars missions (from Mars PathFinder to Mars Exploration Rover) and on the International Space Station.

  19. Hi-G electronic gated camera for precision trajectory analysis

    NASA Astrophysics Data System (ADS)

    Snyder, Donald R.; Payne, Scott; Keller, Ed; Longo, Salvatore; Caudle, Dennis E.; Walker, Dennis C.; Sartor, Mark A.; Keeler, Joe E.; Kerr, David A.; Fail, R. Wallace; Gannon, Jim; Carrol, Ernie; Jamison, Todd A.

    1997-12-01

    It is extremely difficult and expensive to determine the flight attitude and aimpoint of small maneuvering miniature air vehicles from ground based fixed or tracking photography. Telemetry alone cannot provide sufficient information bandwidth on 'what' the ground tracking is seeing and consequently 'why' it did or did not function properly. Additionally, it is anticipated that 'smart' and 'brilliant' guided vehicles now in development will require a high resolution imaging support system to determine which target and which part of a ground feature is being used for navigation or targeting. Other requirements include support of sub-component separation from developmental supersonic vehicles, where the clean separation from the container is not determinable from ground based film systems and film cameras do not survive vehicle breakup and impact. Hence, the requirement is to develop and demonstrate an imaging support system for development/testing that can provide the flight vehicle developer/analyst with imagery (combined with miniature telemetry sources) sufficient to recreate the trajectory, terminal navigation, and flight termination events. This project is a development and demonstration of a real-time, launch-rated, shuttered, electronic imager, transmitter, and analysis system. This effort demonstrated boresighted imagery from inside small flight vehicles for post flight analysis of trajectory, and capture of ground imagery during random triggered vehicle functions. The initial studies for this capability have been accomplished by the Experimental Dynamics Section of the Air Force Wright Laboratory, Armament Directorate, Eglin AFB, Florida, and the Telemetry Support Branch of the Army Material Research and Development Center at Picatinny Arsenal, New Jersey. It has been determined that at 1/10,000 of a second exposure time, new ultra-miniature CCD sensors have sufficient sensitivity to image key ground target features without blur, thereby providing data for

  20. Precision analysis of the photomultiplier response to ultra low signals

    DOE PAGES

    Degtiarenko, Pavel

    2017-08-05

    Here, a new computational model for the description of the photon detector response functions measured in conditions of low light is presented, together with examples of the observed photomultiplier signal amplitude distributions, successfully described using the parameterized model equation. In extension to the previously known approximations, the new model describes the underlying discrete statistical behavior of the photoelectron cascade multiplication processes in photon detectors with complex non-uniform gain structure of the first dynode. Important features of the model include the ability to represent the true single-photoelectron spectra from different photomultipliers with a variety of parameterized shapes, reflecting the variability inmore » the design and in the individual parameters of the detectors. The new software tool is available for evaluation of the detectors’ performance, response, and efficiency parameters that may be used in various applications including the ultra low background experiments such as the searches for Dark Matter and rare decays, underground neutrino studies, optimizing operations of the Cherenkov light detectors, help in the detector selection procedures, and in the experiment simulations.« less

  1. Application and testing of additive manufacturing for mirrors and precision structures

    NASA Astrophysics Data System (ADS)

    Sweeney, Michael; Acreman, Martyn; Vettese, Tom; Myatt, Ray; Thompson, Mike

    2015-09-01

    Additive Manufacturing (aka AM, and 3-D printing) is widely touted in the media as the foundation for the next industrial revolution. Beneath the hype, AM does indeed offer profound advantages in lead-time, dramatically reduced consumption of expensive raw materials, while enabling new and innovative design forms that cannot be produced by other means. General Dynamics and their industry partners have begun to embrace this technology for mirrors and precision structures used in the aerospace, defense, and precision optical instrumentation industries. Aggressively lightweighted, open and closed back test mirror designs, 75-150 mm in size, were first produced by AM from several different materials. Subsequent optical finishing and test experiments have exceeded expectations for density, surface finish, dimensional stability and isotropy of thermal expansion on the optical scale of measurement. Materials currently under examination include aluminum, titanium, beryllium, aluminum beryllium, Inconel 625, stainless steel/bronze, and PEKK polymer.

  2. Automated On-board Terrain Analysis for Precision Landings

    NASA Technical Reports Server (NTRS)

    Rahman, Zia-ur; Jobson, Daniel J.; Woodell, Glenn A.; Hines, Glenn D.

    2006-01-01

    Advances in space robotics technology hinge to a large extent upon the development and deployment of sophisticated new vision-based methods for automated in-space mission operations and scientific survey. To this end, we have developed a new concept for automated terrain analysis that is based upon a generic image enhancement platform-multi-scale Retinex (MSR) and visual servo (VS) processing. This pre-conditioning with the MSR and the VS produces a "canonical" visual representation that is largely independent of lighting variations, and exposure errors. Enhanced imagery is then processed with a biologically inspired two-channel edge detection process, followed by a smoothness based criteria for image segmentation. Landing sites can be automatically determined by examining the results of the smoothness-based segmentation which shows those areas in the image that surpass a minimum degree of smoothness. Though the MSR has proven to be a very strong enhancement engine, the other elements of the approach, the VS, terrain map generation, and smoothness-based segmentation, are in early stages of development. Experimental results on data from the Mars Global Surveyor show that the imagery can be processed to automatically obtain smooth landing sites. In this paper, we describe the method used to obtain these landing sites, and also examine the smoothness criteria in terms of the imager and scene characteristics. Several examples of applying this method to simulated and real imagery are shown.

  3. Automated, on-board terrain analysis for precision landings

    NASA Technical Reports Server (NTRS)

    Rahman, Zia-ur; Jobson, Daniel J.; Woodell, Glenn A.; Hines, Glenn D.

    2006-01-01

    Advances in space robotics technology hinge to a large extent upon the development and deployment of sophisticated new vision-based methods for automated in-space mission operations and scientific survey. To this end, we have developed a new concept for automated terrain analysis that is based upon a generic image enhancement platform|multi-scale retinex (MSR) and visual servo (VS) processing. This pre-conditioning with the MSR and the vs produces a "canonical" visual representation that is largely independent of lighting variations, and exposure errors. Enhanced imagery is then processed with a biologically inspired two-channel edge detection process, followed by a smoothness based criteria for image segmentation. Landing sites can be automatically determined by examining the results of the smoothness-based segmentation which shows those areas in the image that surpass a minimum degree of smoothness. Though the msr has proven to be a very strong enhancement engine, the other elements of the approach|the vs, terrain map generation, and smoothness-based segmentation|are in early stages of development. Experimental results on data from the Mars Global Surveyor show that the imagery can be processed to automatically obtain smooth landing sites. In this paper, we describe the method used to obtain these landing sites, and also examine the smoothness criteria in terms of the imager and scene characteristics. Several examples of applying this method to simulated and real imagery are shown.

  4. Automated On-board Terrain Analysis for Precision Landings

    NASA Technical Reports Server (NTRS)

    Rahman, Zia-ur; Jobson, Daniel J.; Woodell, Glenn A.; Hines, Glenn D.

    2006-01-01

    Advances in space robotics technology hinge to a large extent upon the development and deployment of sophisticated new vision-based methods for automated in-space mission operations and scientific survey. To this end, we have developed a new concept for automated terrain analysis that is based upon a generic image enhancement platform-multi-scale Retinex (MSR) and visual servo (VS) processing. This pre-conditioning with the MSR and the VS produces a "canonical" visual representation that is largely independent of lighting variations, and exposure errors. Enhanced imagery is then processed with a biologically inspired two-channel edge detection process, followed by a smoothness based criteria for image segmentation. Landing sites can be automatically determined by examining the results of the smoothness-based segmentation which shows those areas in the image that surpass a minimum degree of smoothness. Though the MSR has proven to be a very strong enhancement engine, the other elements of the approach, the VS, terrain map generation, and smoothness-based segmentation, are in early stages of development. Experimental results on data from the Mars Global Surveyor show that the imagery can be processed to automatically obtain smooth landing sites. In this paper, we describe the method used to obtain these landing sites, and also examine the smoothness criteria in terms of the imager and scene characteristics. Several examples of applying this method to simulated and real imagery are shown.

  5. Streamlined design and self reliant hardware for active control of precision space structures

    NASA Technical Reports Server (NTRS)

    Hyland, David C.; King, James A.; Phillips, Douglas J.

    1994-01-01

    Precision space structures may require active vibration control to satisfy critical performance requirements relating to line-of-sight pointing accuracy and the maintenance of precise, internal alignments. In order for vibration control concepts to become operational, it is necessary that their benefits be practically demonstrated in large scale ground-based experiments. A unique opportunity to carry out such demonstrations on a wide variety of experimental testbeds was provided by the NASA Control-Structure Integration (CSI) Guest Investigator (GI) Program. This report surveys the experimental results achieved by the Harris Corporation GI team on both Phases 1 and 2 of the program and provides a detailed description of Phase 2 activities. The Phase 1 results illustrated the effectiveness of active vibration control for space structures and demonstrated a systematic methodology for control design, implementation test. In Phase 2, this methodology was significantly streamlined to yield an on-site, single session design/test capability. Moreover, the Phase 2 research on adaptive neural control techniques made significant progress toward fully automated, self-reliant space structure control systems. As a further thrust toward productized, self-contained vibration control systems, the Harris Phase II activity concluded with experimental demonstration of new vibration isolation hardware suitable for a wide range of space-flight and ground-based commercial applications.The CSI GI Program Phase 1 activity was conducted under contract NASA1-18872, and the Phase 2 activity was conducted under NASA1-19372.

  6. A Method for Assessing the Accuracy of a Photogrammetry System for Precision Deployable Structures

    NASA Technical Reports Server (NTRS)

    Moore, Ashley

    2005-01-01

    The measurement techniques used to validate analytical models of large deployable structures are an integral Part of the technology development process and must be precise and accurate. Photogrammetry and videogrammetry are viable, accurate, and unobtrusive methods for measuring such large Structures. Photogrammetry uses Software to determine the three-dimensional position of a target using camera images. Videogrammetry is based on the same principle, except a series of timed images are analyzed. This work addresses the accuracy of a digital photogrammetry system used for measurement of large, deployable space structures at JPL. First, photogrammetry tests are performed on a precision space truss test article, and the images are processed using Photomodeler software. The accuracy of the Photomodeler results is determined through, comparison with measurements of the test article taken by an external testing group using the VSTARS photogrammetry system. These two measurements are then compared with Australis photogrammetry software that simulates a measurement test to predict its accuracy. The software is then used to study how particular factors, such as camera resolution and placement, affect the system accuracy to help design the setup for the videogrammetry system that will offer the highest level of accuracy for measurement of deploying structures.

  7. Accuracy and Precision of Silicon Based Impression Media for Quantitative Areal Texture Analysis

    PubMed Central

    Goodall, Robert H.; Darras, Laurent P.; Purnell, Mark A.

    2015-01-01

    Areal surface texture analysis is becoming widespread across a diverse range of applications, from engineering to ecology. In many studies silicon based impression media are used to replicate surfaces, and the fidelity of replication defines the quality of data collected. However, while different investigators have used different impression media, the fidelity of surface replication has not been subjected to quantitative analysis based on areal texture data. Here we present the results of an analysis of the accuracy and precision with which different silicon based impression media of varying composition and viscosity replicate rough and smooth surfaces. Both accuracy and precision vary greatly between different media. High viscosity media tested show very low accuracy and precision, and most other compounds showed either the same pattern, or low accuracy and high precision, or low precision and high accuracy. Of the media tested, mid viscosity President Jet Regular Body and low viscosity President Jet Light Body (Coltène Whaledent) are the only compounds to show high levels of accuracy and precision on both surface types. Our results show that data acquired from different impression media are not comparable, supporting calls for greater standardisation of methods in areal texture analysis. PMID:25991505

  8. Accuracy and Precision of Silicon Based Impression Media for Quantitative Areal Texture Analysis

    NASA Astrophysics Data System (ADS)

    Goodall, Robert H.; Darras, Laurent P.; Purnell, Mark A.

    2015-05-01

    Areal surface texture analysis is becoming widespread across a diverse range of applications, from engineering to ecology. In many studies silicon based impression media are used to replicate surfaces, and the fidelity of replication defines the quality of data collected. However, while different investigators have used different impression media, the fidelity of surface replication has not been subjected to quantitative analysis based on areal texture data. Here we present the results of an analysis of the accuracy and precision with which different silicon based impression media of varying composition and viscosity replicate rough and smooth surfaces. Both accuracy and precision vary greatly between different media. High viscosity media tested show very low accuracy and precision, and most other compounds showed either the same pattern, or low accuracy and high precision, or low precision and high accuracy. Of the media tested, mid viscosity President Jet Regular Body and low viscosity President Jet Light Body (Coltène Whaledent) are the only compounds to show high levels of accuracy and precision on both surface types. Our results show that data acquired from different impression media are not comparable, supporting calls for greater standardisation of methods in areal texture analysis.

  9. Nd:YAG laser micromachining of SiC precision structures for MEMS

    NASA Astrophysics Data System (ADS)

    Kreutz, Ernst-Wolfgang; Weichenhain, Ruth; Horn, Alexander

    2001-04-01

    Micromachining of SiC with 1(omega) , 2(omega) , 3(omega) -Nd:YAG laser radiation with pulse durations in the ps to ns regime is performed in various processing gas atmospheres as a function of processing variables showing the influence of the heat and pressure load onto the precision of geometric structures generated. The physical and chemical processes involved in micromachining with laser radiation are characterized by a machine vision system and the produced structures are analyzed by profilometry, optical and electron microscopy as well as X- photoelectron spectroscopy. 3D microstructures are produced by scanning and turning the laser beam onto the material surface, width of structures < 100 micrometers and surface roughness < 2 micrometers , for example, require an overlap < 0.8 independent of the type of processing gas under investigation.

  10. Geopositioning Precision Analysis of Multiple Image Triangulation Using Lro Nac Lunar Images

    NASA Astrophysics Data System (ADS)

    Di, K.; Xu, B.; Liu, B.; Jia, M.; Liu, Z.

    2016-06-01

    This paper presents an empirical analysis of the geopositioning precision of multiple image triangulation using Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) images at the Chang'e-3(CE-3) landing site. Nine LROC NAC images are selected for comparative analysis of geopositioning precision. Rigorous sensor models of the images are established based on collinearity equations with interior and exterior orientation elements retrieved from the corresponding SPICE kernels. Rational polynomial coefficients (RPCs) of each image are derived by least squares fitting using vast number of virtual control points generated according to rigorous sensor models. Experiments of different combinations of images are performed for comparisons. The results demonstrate that the plane coordinates can achieve a precision of 0.54 m to 2.54 m, with a height precision of 0.71 m to 8.16 m when only two images are used for three-dimensional triangulation. There is a general trend that the geopositioning precision, especially the height precision, is improved with the convergent angle of the two images increasing from several degrees to about 50°. However, the image matching precision should also be taken into consideration when choosing image pairs for triangulation. The precisions of using all the 9 images are 0.60 m, 0.50 m, 1.23 m in along-track, cross-track, and height directions, which are better than most combinations of two or more images. However, triangulation with selected fewer images could produce better precision than that using all the images.

  11. Lake Erie Yellow perch age estimation based on three structures: Precision, processing times, and management implications

    USGS Publications Warehouse

    Vandergoot, C.S.; Bur, M.T.; Powell, K.A.

    2008-01-01

    Yellow perch Perca flavescens support economically important recreational and commercial fisheries in Lake Erie and are intensively managed. Age estimation represents an integral component in the management of Lake Erie yellow perch stocks, as age-structured population models are used to set safe harvest levels on an annual basis. We compared the precision associated with yellow perch (N = 251) age estimates from scales, sagittal otoliths, and anal spine sections and evaluated the time required to process and estimate age from each structure. Three readers of varying experience estimated ages. The precision (mean coefficient of variation) of estimates among readers was 1% for sagittal otoliths, 5-6% for anal spines, and 11-13% for scales. Agreement rates among readers were 94-95% for otoliths, 71-76% for anal spines, and 45-50% for scales. Systematic age estimation differences were evident among scale and anal spine readers; less-experienced readers tended to underestimate ages of yellow perch older than age 4 relative to estimates made by an experienced reader. Mean scale age tended to underestimate ages of age-6 and older fish relative to otolith ages estimated by an experienced reader. Total annual mortality estimates based on scale ages were 20% higher than those based on otolith ages; mortality estimates based on anal spine ages were 4% higher than those based on otolith ages. Otoliths required more removal and preparation time than scales and anal spines, but age estimation time was substantially lower for otoliths than for the other two structures. We suggest the use of otoliths or anal spines for age estimation in yellow perch (regardless of length) from Lake Erie and other systems where precise age estimates are necessary, because age estimation errors resulting from the use of scales could generate incorrect management decisions. ?? Copyright by the American Fisheries Society 2008.

  12. Current Work to Improve Precision in Measurements of Helium Fine Structure

    NASA Astrophysics Data System (ADS)

    Hassan Rezaeian, Nima; Shiner, Davis

    2013-05-01

    With the recent improvement on the 23P Helium fine structure calculation by Pachucki and the quest for finding the most precise value for α, spectroscopic measurement of the helium atom has a great advantage to find this primary constant. Distinctively, the 32 GHz atomic fine structure of 23P J2 to J0 interval with uncertainty of 100Hz leads a factor of three better than the best current value of α and an impulsion to the theory to evaluate the largest term of order mα8 is our ambition. This measurement not only tests the quantum electrodynamics, but also establishes the fine structure constant α with uncertainty of 1.6 ppb. The electron g-factor measurement of α, even though, is by far more accurate at 0.37 ppb, our end result would be a examination to the best alternative atom recoil measurements with different approach. To reach on this level of accuracy, we implement our frequency selector with precision better than 1 to 100 along with laser cooling mechanism to enhance the signal to noise ratio by increasing the signal strength. This work is supported by NSF grant.

  13. Current Work to Improve Precision in Measurements of Helium Fine Structure

    NASA Astrophysics Data System (ADS)

    Hassan Rezaeian, Nima; Shiner, David

    2013-06-01

    With the recent improvement on the 23P Helium fine structure calculation by Pachucki and the quest for finding the most precise value for α, spectroscopic measurement of the helium atom has a great advantage to find this primary constant. Distinctively, the 32 GHz atomic fine structure of 23P J2 to J0 interval with uncertainty of 100Hz leads a factor of three better than the best current value of α and an impulsion to the theory to evaluate the largest term of order mα8 is our ambition. This measurement not only tests the quantum electrodynamics, but also establishes the fine structure constant α with uncertainty of 1.6 ppb. The electron g-factor measurement of α, even though, is by far more accurate at 0.37 ppb, our end result would be a examination to the best alternative atom recoil measurements with different approach. To reach on this level of accuracy, we implement our frequency selector with precision better than 1 to 100 along with laser cooling mechanism to enhance the signal to noise ratio by increasing the signal strength. This work is supported by NSF grant.

  14. The Spacing Effect for Structural Synaptic Plasticity Provides Specificity and Precision in Plastic Changes.

    PubMed

    San Martin, Alvaro; Rela, Lorena; Gelb, Bruce; Pagani, Mario Rafael

    2017-05-10

    In contrast to trials of training without intervals (massed training), training trials spaced over time (spaced training) induce a more persistent memory identified as long-term memory (LTM). This phenomenon, known as the spacing effect for memory, is poorly understood. LTM is supported by structural synaptic plasticity; however, how synapses integrate spaced stimuli remains elusive. Here, we analyzed events of structural synaptic plasticity at the single-synapse level after distinct patterns of stimulation in motoneurons of Drosophila We found that the spacing effect is a phenomenon detected at synaptic level, which determines the specificity and the precision in structural synaptic plasticity. Whereas a single pulse of stimulation (massed) induced structural synaptic plasticity, the same amount of stimulation divided in three spaced stimuli completely prevented it. This inhibitory effect was determined by the length of the interstimulus intervals. The inhibitory effect of the spacing was lost by suppressing the activity of Ras or mitogen-activated protein kinase, whereas the overexpression of Ras-WT enhanced it. Moreover, dividing the same total time of stimulation into five or more stimuli produced a higher precision in the number of events of plasticity. Ras mutations associated with intellectual disability abolished the spacing effect and led neurons to decode distinct stimulation patterns as massed stimulation. This evidence suggests that the spacing effect for memory may result from the effect of the spacing in synaptic plasticity, which appears to be a property not limited to neurons involved in learning and memory. We propose a model of spacing-dependent structural synaptic plasticity.SIGNIFICANCE STATEMENT Long-term memory (LTM) induced by repeated trials spaced over time is known as the spacing effect, a common property in the animal kingdom. Altered mechanisms in the spacing effect have been found in animal models of disorders with intellectual

  15. High precision measurements of the neutron spin structure in Hall A at Jlab

    SciTech Connect

    Annand, R M; Cates, G; Cisbani, E; Franklin, G B; Liyanage, N; Puckett, A; Rosner, G; Wojtsekhowski, B; Zheng, X

    2012-04-01

    Conclusions of this presentation are: (1) JLab energy upgrade will offer new exciting opportunities to study the nucleon (spin) structure such as high precision, unexplored phase space, flavor decomposition; (2) Large technological efforts is in progress to optimally exploit these opportunities; (3) HallA will be the first hall to get the new beam, first experiment expected to run in 2014; (4) A1n likely one of the first experiments to take data in the new 12 GeV era; and (5) SIDIS exp. will follow in couple of years.

  16. Simultaneous precision positioning and vibration suppression of an intelligent composite satellite structure utilizing piezoelectric sensors and actuators

    NASA Astrophysics Data System (ADS)

    Doherty, Kathleen Marie

    Adaptive or intelligent structures which have the capability for sensing and responding to their environment promise a novel approach to satisfying the stringent performance requirements of future space missions. This research effort focuses on the development of a smart thruster mount truss structure with precision positioning and active vibration suppression capability for use in a space satellite. The smart thruster mount would utilize piezoelectric sensors and actuators for precision positioning to provide fine tuning of position tolerance for thruster alignment. The same structure may be used for suppressing the vibration that resonates throughout the spacecraft during thruster firing. This vibration renders sensitive optical or measurement equipment non-operational until the disturbance has dissipated. This smart system approach would greatly enhance mission performance by fine tuning attitude control, potentially eliminating the nonoperational period as well as minimizing fuel consumption utilized for position correction. The configuration of the smart thruster mount truss system is that of a modified Stewart platform. Precision positioning of the truss structure is achieved using active members which extend or contract to tilt the upper platform where the thruster is mounted. An inverse kinematic analysis of a modified Stewart platform has been developed and is used to determine the required axial displacement of the active struts for the desired angular tilt of the smart platform. Experimental data is used to verify the precision positioning capabilities of the active struts. This information demonstrates the ability of the active strut to tilt the top of the smart platform by the required angular displacement. Analytical verification of the vibration suppression capabilities of the active struts in the smart composite platform using finite element analysis is presented. A model of an active strut with surface mounted sensors/actuators was used to develop

  17. Reference conditions for giant sequoia forest restoration: structure, process, and precision

    USGS Publications Warehouse

    Stephenson, Nathan L.

    1999-01-01

    National Park Service policy directs that more natural conditions be restored to giant sequoia groves, which have been altered by a century of fire exclusion. Efforts to find a reasonable and practical definition of “natural” have helped drive scientists and land managers to use past grove conditions as reference conditions for restoration. Extensive research aimed at determining reference conditions has demonstrated that past fire regimes can be characterized with greater precision than past grove structures. Difficulty and imprecision in determining past grove structure has helped fuel a debate between “structural restorationists,” who believe that forest structure should be restored mechanically before fire is reintroduced, and “process restorationists,” who believe that simple reintroduction of fire is appropriate. I evaluate old and new studies from sequoia groves to show that some of the arguments of both groups have been flawed. Importantly, it appears that restoration of fire without a preceding mechanical restoration may restore the pre-Euro-American structure of sequoia groves, at least within the bounds of our imprecise knowledge of past grove structure. However, the same may not be true for all forest types that have experienced lengthy fire exclusion. Our ability to draw robust generalizations about fire's role in forest restoration will depend heavily on a thorough understanding of past and present interactions among climate, fire, and forest structure. Use of reference conditions will be central to developing this understanding.

  18. Precise control of agarose media pore structure by regulating cooling rate.

    PubMed

    Chen, Chao; Li, Xiunan; Zhao, Dawei; Li, Yaqiong; Shi, Hong; Ma, Guanghui; Su, Zhiguo

    2017-09-19

    A porous structure is the key factor to successful chromatography separation. Agarose gel as one of the most popular porous media has been extensively used in chromatography separation. As the cooling process in the agarose gelation procedure can directly influence the pore structure, ten kinds of 4% agarose media with different cooling rates from 0.132 to 16.7°C/min were synthesized, and the pore structure was determined accurately by using low-field NMR spectroscopy. The curves of pore structure and cooling rate can be divided into two stages with the boundary of 6°C/min. In stage I, the pore structure met a power equation with the decrease of the cooling rate, and in stage II, the process reached a plateau. Confirmatory experiments proved that, by adjusting the cooling rate, a precise control of the pore structure of agarose media can be realized, furthermore, cooling rate optimization was an effective way to control the pore size of agarose media and can further tailor the pore structure for more effective separation of different proteins. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  19. Precise colocalization of interacting structural and pigmentary elements generates extensive color pattern variation in Phelsuma lizards.

    PubMed

    Saenko, Suzanne V; Teyssier, Jérémie; van der Marel, Dirk; Milinkovitch, Michel C

    2013-10-07

    Color traits in animals play crucial roles in thermoregulation, photoprotection, camouflage, and visual communication, and are amenable to objective quantification and modeling. However, the extensive variation in non-melanic pigments and structural colors in squamate reptiles has been largely disregarded. Here, we used an integrated approach to investigate the morphological basis and physical mechanisms generating variation in color traits in tropical day geckos of the genus Phelsuma. Combining histology, optics, mass spectrometry, and UV and Raman spectroscopy, we found that the extensive variation in color patterns within and among Phelsuma species is generated by complex interactions between, on the one hand, chromatophores containing yellow/red pteridine pigments and, on the other hand, iridophores producing structural color by constructive interference of light with guanine nanocrystals. More specifically, we show that 1) the hue of the vivid dorsolateral skin is modulated both by variation in geometry of structural, highly ordered narrowband reflectors, and by the presence of yellow pigments, and 2) that the reflectivity of the white belly and of dorsolateral pigmentary red marks, is increased by underlying structural disorganized broadband reflectors. Most importantly, these interactions require precise colocalization of yellow and red chromatophores with different types of iridophores, characterized by ordered and disordered nanocrystals, respectively. We validated these results through numerical simulations combining pigmentary components with a multilayer interferential optical model. Finally, we show that melanophores form dark lateral patterns but do not significantly contribute to variation in blue/green or red coloration, and that changes in the pH or redox state of pigments provide yet another source of color variation in squamates. Precisely colocalized interacting pigmentary and structural elements generate extensive variation in lizard color

  20. Planning future studies based on the precision of network meta-analysis results.

    PubMed

    Nikolakopoulou, Adriani; Mavridis, Dimitris; Salanti, Georgia

    2016-03-30

    When there are multiple competing interventions for a healthcare problem, the design of new studies could be based on the entire network of evidence as reflected in a network meta-analysis. There is a practical need to answer how many (if any) studies are needed, of which design (i.e., which treatments to compare), and with what sample size to infer conclusively about the relative treatment effects of a set of target or all competing treatments and their relative ranking. We consider the precision in the results obtained from network meta-analysis: the precision of the joint distribution of the estimated basic parameters of the model and the precision in the treatment ranking. We quantify the precision in the estimated effects by considering their variance-covariance matrix and estimate the precision in ranking by quantifying the dissimilarity of the density functions of summary effect estimates. Then, based on a desirable improvement in precision, we calculate the required sample size for each possible study design and number of study arms, and we present visual tools that can help trialists select the optimal study design. We use a published network of interventions for the treatment of hepatocellular carcinoma to illustrate the suggested methodology. The presented methodology can aid investigators making informed and evidence-based decisions about planning new studies.

  1. Crystallization-induced emission enhancement: A novel fluorescent Au-Ag bimetallic nanocluster with precise atomic structure

    PubMed Central

    Chen, Tao; Yang, Sha; Chai, Jinsong; Song, Yongbo; Fan, Jiqiang; Rao, Bo; Sheng, Hongting; Yu, Haizhu; Zhu, Manzhou

    2017-01-01

    We report the first noble metal nanocluster with a formula of Au4Ag13(DPPM)3(SR)9 exhibiting crystallization-induced emission enhancement (CIEE), where DPPM denotes bis(diphenylphosphino)methane and HSR denotes 2,5-dimethylbenzenethiol. The precise atomic structure is determined by x-ray crystallography. The crystalline state of Au4Ag13 shows strong luminescence at 695 nm, in striking contrast to the weak emission of the amorphous state and hardly any emission in solution phase. The structural analysis and the density functional theory calculations imply that the compact C–H⋯π interactions significantly restrict the intramolecular rotations and vibrations and thus considerably enhance the radiative transitions in the crystalline state. Because the noncovalent interactions can be easily modulated via varying the chemical environments, the CIEE phenomenon might represent a general strategy to amplify the fluorescence from weakly (or even non-) emissive nanoclusters. PMID:28835926

  2. Precise Point Positioning for the Efficient and Robust Analysis of GPS Data from Large Networks

    NASA Technical Reports Server (NTRS)

    Zumberge, J. F.; Heflin, M. B.; Jefferson, D. C.; Watkins, M. M.; Webb, F. H.

    1997-01-01

    Networks of dozens to hundreds of permanently operating precision Global Positioning System (GPS) receivers are emerging at spatial scales that range from 10(exp 0) to 10(exp 3) km. To keep the computational burden associated with the analysis of such data economically feasible, one approach is to first determine precise GPS satellite positions and clock corrections from a globally distributed network of GPS receivers. Their, data from the local network are analyzed by estimating receiver- specific parameters with receiver-specific data satellite parameters are held fixed at their values determined in the global solution. This "precise point positioning" allows analysis of data from hundreds to thousands of sites every (lay with 40-Mflop computers, with results comparable in quality to the simultaneous analysis of all data. The reference frames for the global and network solutions can be free of distortion imposed by erroneous fiducial constraints on any sites.

  3. Precise Point Positioning for the Efficient and Robust Analysis of GPS Data From Large Networks

    NASA Technical Reports Server (NTRS)

    Zumberge, J. F.; Heflin, M. B.; Jefferson, D. C.; Watkins, M. M.; Webb, F. H.

    1997-01-01

    Networks of dozens to hundreds of permanently operating precision Global Positioning System (GPS) receivers are emerging at spatial scales that range from 10(exp 0) to 10(exp 3) km. To keep the computational burden associated with the analysis of such data economically feasible, one approach is to first determine precise GPS satellite positions and clock corrections from a globally distributed network of GPS receivers. Then, data from the local network are analyzed by estimating receiver specific parameters with receiver-specific data; satellite parameters are held fixed at their values determined in the global solution. This "precise point positioning" allows analysis of data from hundreds to thousands of sites every day with 40 Mflop computers, with results comparable in quality to the simultaneous analysis of all data. The reference frames for the global and network solutions can be free of distortion imposed by erroneous fiducial constraints on any sites.

  4. A Precision Measurement of the Spin Structure Function G(2)(P)

    SciTech Connect

    Benmouna, N

    2004-01-05

    The spin structure function g{sub 2}(x,Q{sup 2}) and the virtual photon asymmetry A{sub 2}(x,Q{sup 2}) were measured for the proton using deep inelastic scattering. The experiment was conducted at the Stanford Linear Accelerator Center (SLAC), where longitudinally polarized electrons at 29.1 and 32.3 GeV were scattered from a transversely polarized NH{sub 3} target. Large data sets were accumulated using three independent spectrometers covering a kinematic range 0.02 {le} x {le} 0.8 and 1 {le} Q{sup 2} {le} 20 (GeV/c){sup 2}. This new data is the first data precise enough to distinguish between current models for the proton. The structure function g{sub 2}{sup p} was found to be reasonably consistent with the twist-2 Wandzura-Wilczek calculation. The Q{sup 2} dependence of g{sub 2} approximately follows the Q{sup 2} dependence of g{sub 2}{sup WW}, although the data are not precise enough to rule out no Q{sup 2} dependence. The absolute value for A{sub 2}{sup p} was found to be significantly smaller than the Soffer limit over the measured range. The virtual photon asymmetry A{sub 2} was also found to be inconsistent with zero over much of the measured range.

  5. A Precise Measurement of the Deuteron Elastic Structure Function A(Q2)

    SciTech Connect

    Honegger, Andrian

    1999-12-07

    During summer 1997 experiment 394-018 measured the deuteron tensor polarization in D(e,e'$vec\\{d}$) scattering in Hall C at Jefferson Laboratory. In a momentum transfer range between 0.66 and 1.8 (GeV=c)2, with slight changes in the experimental setup, the collaboration performed six precision measurements of the deuteron structure function A(Q2) in elastic D(e,e'd) scattering . Scattered electrons and recoil deuterons were detected in coincidence in the High Momentum Spectrometer and the recoil polarimeter POLDER, respectively. At every kinematics H(e,e') data were taken to study systematic effects of the measurement. These new precise measurements resolve discrepancies between older data sets and put significant constraints on existing models of the deuteron electromagnetic structure. This work was supported by the Swiss National Science Foundation, the French Centre National de la Recherche Scientifique and the Commissariat 'a l'Energie Atomique, the U.S. Department of Energy and the National Science Foundation and the K.C. Wong Foundation.

  6. Generalized Structured Component Analysis

    ERIC Educational Resources Information Center

    Hwang, Heungsun; Takane, Yoshio

    2004-01-01

    We propose an alternative method to partial least squares for path analysis with components, called generalized structured component analysis. The proposed method replaces factors by exact linear combinations of observed variables. It employs a well-defined least squares criterion to estimate model parameters. As a result, the proposed method…

  7. Picometre-precision analysis of scanning transmission electron microscopy images of platinum nanocatalysts.

    PubMed

    Yankovich, Andrew B; Berkels, Benjamin; Dahmen, W; Binev, P; Sanchez, S I; Bradley, S A; Li, Ao; Szlufarska, Izabela; Voyles, Paul M

    2014-06-11

    Measuring picometre-scale shifts in the positions of individual atoms in materials provides new insight into the structure of surfaces, defects and interfaces that influence a broad variety of materials' behaviour. Here we demonstrate sub-picometre precision measurements of atom positions in aberration-corrected Z-contrast scanning transmission electron microscopy images based on the non-rigid registration and averaging of an image series. Non-rigid registration achieves five to seven times better precision than previous methods. Non-rigidly registered images of a silica-supported platinum nanocatalyst show pm-scale contraction of atoms at a (111)/(111) corner towards the particle centre and expansion of a flat (111) facet. Sub-picometre precision and standardless atom counting with <1 atom uncertainty in the same scanning transmission electron microscopy image provide new insight into the three-dimensional atomic structure of catalyst nanoparticle surfaces, which contain the active sites controlling catalytic reactions.

  8. Surface micro-structuring of glassy carbon for precision glass molding of diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans Peter; Hermerschmidt, Andreas

    2014-09-01

    Glassy carbon is used nowadays for a variety of applications because of its mechanical strength, thermal stability and non-sticking adhesion properties. This makes it also a suitable candidate as mold material for precision compression molding of low and high glass-transition temperature materials. To fabricate molds for diffractive optics a highresolution structuring technique is needed. We introduce a process that allows the micro-structuring of glassy carbon by reactive ion etching. Key parameters such as uniformity, surface roughness, edge definition and lateral resolution are discussed. They are the most relevant parameters for a stamp in optical applications. The use of titanium as a hard mask makes it possible to achieve a reasonable selectivity of 4:1, which has so far been one of the main problems in microstructuring of glassy carbon. We investigate the titanium surface structure with its 5-10 nm thick layer of TiO2 grains and its influence on the shape of the hard mask. In our fabrication procedure we were able to realize optically flat diffractive structures with slope angles of more than 80° at typical feature sizes of 5 μm and at 700 nm depth. The fabricated glassy carbon molds were applied to thermal imprinting onto different glasses. Glassy carbon molds with 1 mm thickness were tested with binary optical structures. Our experiments show the suitability of glassy carbon as molds for cost efficient mass production with a high quality.

  9. [Biomineralization--precision of shape, structure and properties controlled by proteins].

    PubMed

    Hołubowicz, Rafał; Porębska, Aleksandra; Poznar, Monika; Różycka, Mirosława; Dobryszycki, Piotr

    2015-01-01

    ABSTRACT Biomineralization is the process of the formation of crystal structures that is under biological control. Living organisms produce structures such as bone, teeth, otoliths, otoconia or shells. Although the chemical composition of these tissues is similar to corresponding inorganic minerals, their structure and mechanical properties differ significantly. This may be because of how they are adapted for the functions they perform. The precise control of the formation of biominerals starting with the early nucleation stage influences how the final tissues are formed. The key factors which determine the size, shape, internal structure and properties of biominerals are proteins which control the nucleation and growth of the crystals. Biomineralization is a multi-step process involving protein-protein interactions, as well as interactions between proteins and inorganic fraction. Due to their specific properties, intrinsically disordered proteins (IDPs) perform a particularly important role in the control of the biomineralization process. This article contains an overview of biominerals that are naturally occurring and describes the structures and mineralization mechanisms of the most important of them. The main part of this work was dedicated to the role of proteins which control crystal growth.

  10. Metric precision via soft-tissue landmarks in three-dimensional structured-light scans of human faces.

    PubMed

    Fink, M; Medelnik, J; Strobel, K; Hirschfelder, U; Hofmann, E

    2014-03-01

    The goal of the current work was to investigate the suitability of ten facial soft-tissue landmarks (trichion, glabella, nasion, left and right orbital, subnasal, left and right porion, pogonion, gnathion) as reference points for metric facial analysis by analyzing their intra- and interserial precision in all three dimensions. The faces of 32 volunteers were scanned using a standardized protocol with a structured-light scanner (FaceSCAN(3D) Scientific Photolab 60 Hz; 3D Shape, Erlangen, Germany). Three examiners placed the landmarks twice within a 2-week interval. Image processing (Onyx Ceph(3); Image Instruments; Chemnitz, Germany) and statistical (SAS 9.2; SAS Institute, Cary, NC, USA) software was used for analysis. All measurements were corrected for mean values per patient and analyzed for intraserial and interserial error by model II ANOVA for a simple classification with random effects. Median intraserial precision was 0.40 mm (range 0.05-1.01 mm) overall, including 0.40 mm (0.33-0.85 mm) on the x-axis, 0.64 mm (0.36-0.87 mm) on the y-axis, and 0.27 mm (0.05-1.01 mm) on the z-axis. Interserial precision was substantially lower at a median of 0.05 mm (0-0.22 mm), often not statistically assessable with intraserial precision. We observed no landmark-associated differences; in particular, the medians of the bilateral landmarks orbital (intraserial: 0.40 mm; interserial: 0.02 mm) and porion (intraserial: 0.36 mm; interserial: small and not assessable) were in the middle of the range of our results. Trichion (intraserial: 0.73 mm; interserial: 0.05 mm) and gnathion (intraserial: 0.87 mm; interserial: 0.20 mm) revealed the highest degrees of intraserial measurement imprecision. Outliers were identified in 1.2% (64 of 5400) of measurements. All selected landmarks offer suitably high levels of intra- and interserial precision for the three-dimensional (3D) metric assessment of facial soft-tissue parameters. No difference between (bi)lateral and facial midline

  11. Initial study of applying GSI to precisely use all observations for Rapid Update Analysis

    NASA Astrophysics Data System (ADS)

    Liu, M.; Hu, M.

    2016-12-01

    The Gridpoint Statistical Interpolation (GSI) Data Assimilation System has been developed as the analysis component of both global (GFS) and regional (RAP, NAM, HRRR) numerical weather forecast in NOAA/NCEP. The analysis results are tuned for improving the forecast skills instead of fitting closely to the observations. Thus, most of the analysis fields of GSI do not precisely reflect the observations and cannot be used by forecasters as a "truth" for nowcasting and verification. As an advanced operational data analysis system, GSI should be able to give analysis fields that precisely use all the observations to reflect the real atmospheric status. This study is to investigate how to calibrate the GSI to achieve this goal. To make the analysis close to the observations, the observation and background error covariance are modified and evaluated using regional ARW cases. The test shows that reducing background impact scale and decreasing background variance play the most important and sensitive role to push the analysis toward the observations. At the same time, it is found that the precise analysis of the observation needs to consider the impact of terrain or coast on temperature, surface pressure, and moisture. An algorithm is developed to deal with the impact of observations near coastline on analysis grid explicitly. Both ideal and real cases were conducted to test and verify the algorithm under different seasons and resolutions. Results show that the algorithm can distinguish the characteristics of coastal observations automatically, and then improve the analysis in the vicinity of shorlines.

  12. Support trusses for large precision segmented reflectors: Preliminary design and analysis

    NASA Technical Reports Server (NTRS)

    Collins, Timothy J.; Fichter, W. B.

    1989-01-01

    Precision Segmented Reflector (PSR) technology is currently being developed for a range of future applications such as the Large Deployable Reflector. The structures activities at NASA-Langley are outlined in support of the PSR program. Design concepts are explored for erectable and deployable support structures which are envisioned to be the backbone of these precision reflectors. Important functional requirements for the support trusses related to stiffness, mass, and surface accuracy are reviewed. Proposed geometries for these structures and factors motivating the erectable and deployable designs are discussed. Analytical results related to stiffness, dynamic behavior, and surface accuracy are presented and considered in light of the functional requirements. Results are included for both a 4-meter-diameter prototype support truss which is currently being designed as the Test Bed for the PSR technology development program, and for two 20-meter support structures.

  13. Precision of coherence analysis to detect cerebral autoregulation by near-infrared spectroscopy in preterm infants

    NASA Astrophysics Data System (ADS)

    Hahn, Gitte Holst; Christensen, Karl Bang; Leung, Terence S.; Greisen, Gorm

    2010-05-01

    Coherence between spontaneous fluctuations in arterial blood pressure (ABP) and the cerebral near-infrared spectroscopy signal can detect cerebral autoregulation. Because reliable measurement depends on signals with high signal-to-noise ratio, we hypothesized that coherence is more precisely determined when fluctuations in ABP are large rather than small. Therefore, we investigated whether adjusting for variability in ABP (variabilityABP) improves precision. We examined the impact of variabilityABP within the power spectrum in each measurement and between repeated measurements in preterm infants. We also examined total monitoring time required to discriminate among infants with a simulation study. We studied 22 preterm infants (GA<30) yielding 215 10-min measurements. Surprisingly, adjusting for variabilityABP within the power spectrum did not improve the precision. However, adjusting for the variabilityABP among repeated measurements (i.e., weighting measurements with high variabilityABP in favor of those with low) improved the precision. The evidence of drift in individual infants was weak. Minimum monitoring time needed to discriminate among infants was 1.3-3.7 h. Coherence analysis in low frequencies (0.04-0.1 Hz) had higher precision and statistically more power than in very low frequencies (0.003-0.04 Hz). In conclusion, a reliable detection of cerebral autoregulation takes hours and the precision is improved by adjusting for variabilityABP between repeated measurements.

  14. Multiple projection DEXA scanner for precision bone and muscle loss measurements and analysis during prolonged spaceflight

    NASA Astrophysics Data System (ADS)

    Charles, H. K.; Beck, T. J.; Feldmesser, H. S.; Magee, T. C.; Spisz, T. S.; Pisacane, V. L.

    2000-01-01

    Bone structural information derived from DEXA data is shown to be relevant in explaining BMD loss versus strength-related observations in both aging populations and individuals exposed to microgravity for prolonged periods. Commercial DEXA instruments are limited (and not optimized) to make these critical structural measurements. Progress on the development of a multiple projection DEXA scanner system for making precision bone and muscle loss measurements and their resultant implications on bone strength and fracture risk is described. .

  15. Probabilistic Structural Analysis Program

    NASA Technical Reports Server (NTRS)

    Pai, Shantaram S.; Chamis, Christos C.; Murthy, Pappu L. N.; Stefko, George L.; Riha, David S.; Thacker, Ben H.; Nagpal, Vinod K.; Mital, Subodh K.

    2010-01-01

    NASA/NESSUS 6.2c is a general-purpose, probabilistic analysis program that computes probability of failure and probabilistic sensitivity measures of engineered systems. Because NASA/NESSUS uses highly computationally efficient and accurate analysis techniques, probabilistic solutions can be obtained even for extremely large and complex models. Once the probabilistic response is quantified, the results can be used to support risk-informed decisions regarding reliability for safety-critical and one-of-a-kind systems, as well as for maintaining a level of quality while reducing manufacturing costs for larger-quantity products. NASA/NESSUS has been successfully applied to a diverse range of problems in aerospace, gas turbine engines, biomechanics, pipelines, defense, weaponry, and infrastructure. This program combines state-of-the-art probabilistic algorithms with general-purpose structural analysis and lifting methods to compute the probabilistic response and reliability of engineered structures. Uncertainties in load, material properties, geometry, boundary conditions, and initial conditions can be simulated. The structural analysis methods include non-linear finite-element methods, heat-transfer analysis, polymer/ceramic matrix composite analysis, monolithic (conventional metallic) materials life-prediction methodologies, boundary element methods, and user-written subroutines. Several probabilistic algorithms are available such as the advanced mean value method and the adaptive importance sampling method. NASA/NESSUS 6.2c is structured in a modular format with 15 elements.

  16. A Precision Measurement of the Neutron Spin Structure Functions Using a Polarized HE-3 Target

    SciTech Connect

    Smith, T

    2003-11-05

    This thesis describes a precision measurement of the neutron spin dependent structure function, g{sub 1}{sup n}(x). The measurement was made by the E154 collaboration at SLAC using a longitudinally polarized, 48.3 GeV electron beam, and a {sup 3}He target polarized by spin exchange with optically pumped rubidium. A target polarization as high as 50% was achieved. The elements of the experiment which pertain to the polarized {sup 3}He target will be described in detail in this thesis. To achieve a precision measurement, it has been necessary to minimize the systematic error from the uncertainty in the target parameters. All of the parameters of the target have been carefully measured, and the most important parameters of the target have been measured using multiple techniques. The polarization of the target was measured using nuclear magnetic resonance techniques, and has been calibrated using both proton NMR and by measuring the shift of the Rb Zeeman resonance frequency due to the {sup 3}He polarization. The fraction of events which originated in the {sup 3}He, as measured by the spectrometers, has been determined using a physical model of the target and the spectrometers. It was also measured during the experiment using a variable pressure {sup 3}He reference cell in place of the polarized {sup 3}He target. The spin dependent structure function g{sub 1}{sup n}(z) was measured in the Bjorken x range of 0.014 < x < 0.7 with an average Q{sup 2} of 5 (GeV/c){sup 2}. One of the primary motivations for this experiment was to test the Bjorken sum rule. Because the experiment had smaller statistical errors and a broader kinematic coverage than previous experiments, the behavior of the spin structure function g{sub 1}{sup n}(x) could be studied in detail at low values of the Bjorken scaling variable x. It was found that g{sub 1}{sup n}(x) has a strongly divergent behavior at low values of x, calling into question the methods commonly used to extrapolate the value of g

  17. Small flexible structure for targeted delivery of therapeutic and imaging moieties in precision medicine

    PubMed Central

    Li, Bingjie; Qiu, Xiuchun; Zou, Chaoxia; Ran, Henry; Zhang, Fujun; Ke, Shi

    2016-01-01

    The goals of precision medicine are to link diagnostic and therapeutic agents, improve clinical outcomes, and minimize side effects. We present a simple, small, flexible three-armed core structure that can be conjugated to targeting, imaging, and therapeutic moieties. The targeting molecule can be a peptide, protein, or chemical compound. The diagnostic reporter can be optical and/or nuclear in nature, and can be replaced by chemo- and/or radiotherapeutic compounds for treatment using a single targeting molecule. Imaging components can be used to detect disease biomarkers, monitor treatment response, and guide surgery in real-time to create a tumor-free margin. Isotope impurity can be exploited to visualize whole-body distribution of therapeutic agents. The one-to-one ratio of targeting component to therapeutic agents facilitates dose calculation. The simple synthesis and flexible, modular nature of the agent facilitate high-purity, large-scale production. The core capacity to “seek, treat, and see” may advance precision medicine in the future. PMID:27027441

  18. Multilevel micro-structuring of glassy carbon for precision glass molding of diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans Peter; Plöger, Sven; Hermerschmidt, Andreas

    2015-03-01

    A consumer market for diffractive optical elements in glass can only be created if high efficient elements are available at affordable prices. In diffractive optics the efficiency and optical properties increases with the number of levels used, but in the same way the costs are multiplied by the number if fabrication steps. Replication of multilevel diffractive optical elements in glass would allow cost efficient fabrication but a suitable mold material is needed. Glassy carbon shows a high mechanical strength, thermal stability and non-sticking adhesion properties, which makes it an excellent candidate as mold material for precision compression molding of low and high glass-transition temperature materials. We introduce an 8 level micro structuring process for glassy carbon molds with standard photolithography and a Ti layer as hard mask for reactive ion etching. The molds were applied to thermal imprinting onto low and high transition temperature glass. Optical performance was tested for the molded samples with different designs for laser beamsplitters. The results show a good agreement to the design specification. Our result allow us to show limitations of our fabrication technique and we discussed the suitability of precision glass molding for cost efficient mass production with a high quality.

  19. Precision measurements of large scale structure with future type Ia supernova surveys

    SciTech Connect

    Hannestad, Steen; Haugbolle, Troels; Thomsen, Bjarne E-mail: haugboel@phys.au.dk

    2008-02-15

    Type Ia supernovae are currently the best known standard candles at cosmological distances. In addition to providing a powerful probe of dark energy they are an ideal source of information about the peculiar velocity field of the local universe. Even with the very small number of supernovae presently available it has been possible to measure the dipole and quadrupole of the local velocity field out to z{approx}0.025. With future continuous all-sky surveys like the Large Synoptic Survey Telescope (LSST) project the luminosity distances of tens of thousands of nearby supernovae will be measured accurately. This will allow for a determination of the local velocity structure of the universe as a function of redshift with unprecedented accuracy, provided the redshifts of the host galaxies are known. Using catalogues of mock surveys we estimate that future low redshift supernova surveys will be able to probe {sigma}{sub 8} to a precision of roughly 5% at 95% C.L. This is comparable to the precision in future galaxy and weak lensing surveys, and with a relatively modest observational effort it will provide a crucial cross-check on future measurements of the matter power spectrum.

  20. Precision Attitude Determination System (PADS) design and analysis. Two-axis gimbal star tracker

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Development of the Precision Attitude Determination System (PADS) focused chiefly on the two-axis gimballed star tracker and electronics design improved from that of Precision Pointing Control System (PPCS), and application of the improved tracker for PADS at geosynchronous altitude. System design, system analysis, software design, and hardware design activities are reported. The system design encompasses the PADS configuration, system performance characteristics, component design summaries, and interface considerations. The PADS design and performance analysis includes error analysis, performance analysis via attitude determination simulation, and star tracker servo design analysis. The design of the star tracker and electronics are discussed. Sensor electronics schematics are included. A detailed characterization of the application software algorithms and computer requirements is provided.

  1. Measurement Model and Precision Analysis of Accelerometers for Maglev Vibration Isolation Platforms

    PubMed Central

    Wu, Qianqian; Yue, Honghao; Liu, Rongqiang; Zhang, Xiaoyou; Ding, Liang; Liang, Tian; Deng, Zongquan

    2015-01-01

    High precision measurement of acceleration levels is required to allow active control for vibration isolation platforms. It is necessary to propose an accelerometer configuration measurement model that yields such a high measuring precision. In this paper, an accelerometer configuration to improve measurement accuracy is proposed. The corresponding calculation formulas of the angular acceleration were derived through theoretical analysis. A method is presented to minimize angular acceleration noise based on analysis of the root mean square noise of the angular acceleration. Moreover, the influence of installation position errors and accelerometer orientation errors on the calculation precision of the angular acceleration is studied. Comparisons of the output differences between the proposed configuration and the previous planar triangle configuration under the same installation errors are conducted by simulation. The simulation results show that installation errors have a relatively small impact on the calculation accuracy of the proposed configuration. To further verify the high calculation precision of the proposed configuration, experiments are carried out for both the proposed configuration and the planar triangle configuration. On the basis of the results of simulations and experiments, it can be concluded that the proposed configuration has higher angular acceleration calculation precision and can be applied to different platforms. PMID:26287203

  2. Statistical behavior analysis and precision optimization for the laser stripe center detector based on Steger's algorithm.

    PubMed

    Qi, Li; Zhang, Yixin; Zhang, Xuping; Wang, Shun; Xie, Fei

    2013-06-03

    Triangulation laser range scanning, which has been wildly used in various applications, can reconstruct the 3D geometric of the object with high precision by processing the image of laser stripe. The unbiased line extractor proposed by Steger is one of the most commonly used algorithms in laser stripe center extraction for its precision and robustness. Therefore, it is of great significance to assess the statistical performance of the Steger method when it is applied on laser stripe with Gaussian intensity profile. In this paper, a statistical behavior analysis for the laser stripe center extractor based on Steger method has been carried out. Relationships between center extraction precision, image quality and stripe characteristics have been examined analytically. Optimal scale of Gaussian smoothing kernel can be determined for each laser stripe image to achieve the highest precision according to the derived formula. Flexible three-step noise estimation procedure has been proposed to evaluate the center extraction precision of a typical triangulation laser scanning system by simply referring to the acquired images. The validity of our analysis has been verified by experiments on both artificial and natural images.

  3. Measurement Model and Precision Analysis of Accelerometers for Maglev Vibration Isolation Platforms.

    PubMed

    Wu, Qianqian; Yue, Honghao; Liu, Rongqiang; Zhang, Xiaoyou; Ding, Liang; Liang, Tian; Deng, Zongquan

    2015-08-14

    High precision measurement of acceleration levels is required to allow active control for vibration isolation platforms. It is necessary to propose an accelerometer configuration measurement model that yields such a high measuring precision. In this paper, an accelerometer configuration to improve measurement accuracy is proposed. The corresponding calculation formulas of the angular acceleration were derived through theoretical analysis. A method is presented to minimize angular acceleration noise based on analysis of the root mean square noise of the angular acceleration. Moreover, the influence of installation position errors and accelerometer orientation errors on the calculation precision of the angular acceleration is studied. Comparisons of the output differences between the proposed configuration and the previous planar triangle configuration under the same installation errors are conducted by simulation. The simulation results show that installation errors have a relatively small impact on the calculation accuracy of the proposed configuration. To further verify the high calculation precision of the proposed configuration, experiments are carried out for both the proposed configuration and the planar triangle configuration. On the basis of the results of simulations and experiments, it can be concluded that the proposed configuration has higher angular acceleration calculation precision and can be applied to different platforms.

  4. Error analysis of high-rate GNSS precise point positioning for seismic wave measurement

    NASA Astrophysics Data System (ADS)

    Shu, Yuanming; Shi, Yun; Xu, Peiliang; Niu, Xiaoji; Liu, Jingnan

    2017-06-01

    High-rate GNSS precise point positioning (PPP) has been playing a more and more important role in providing precise positioning information in fast time-varying environments. Although kinematic PPP is commonly known to have a precision of a few centimeters, the precision of high-rate PPP within a short period of time has been reported recently with experiments to reach a few millimeters in the horizontal components and sub-centimeters in the vertical component to measure seismic motion, which is several times better than the conventional kinematic PPP practice. To fully understand the mechanism of mystified excellent performance of high-rate PPP within a short period of time, we have carried out a theoretical error analysis of PPP and conducted the corresponding simulations within a short period of time. The theoretical analysis has clearly indicated that the high-rate PPP errors consist of two types: the residual systematic errors at the starting epoch, which affect high-rate PPP through the change of satellite geometry, and the time-varying systematic errors between the starting epoch and the current epoch. Both the theoretical error analysis and simulated results are fully consistent with and thus have unambiguously confirmed the reported high precision of high-rate PPP, which has been further affirmed here by the real data experiments, indicating that high-rate PPP can indeed achieve the millimeter level of precision in the horizontal components and the sub-centimeter level of precision in the vertical component to measure motion within a short period of time. The simulation results have clearly shown that the random noise of carrier phases and higher order ionospheric errors are two major factors to affect the precision of high-rate PPP within a short period of time. The experiments with real data have also indicated that the precision of PPP solutions can degrade to the cm level in both the horizontal and vertical components, if the geometry of satellites is

  5. Analysis of achievable disturbance attenuation in a precision magnetically-suspended motion control system

    NASA Technical Reports Server (NTRS)

    Kuzin, Alexander V.; Holmes, Michael L.; Behrouzjou, Roxana; Trumper, David L.

    1994-01-01

    The results of the analysis of the achievable disturbance attenuation to get an Angstrom motion control resolution and macroscopic travel in a precision magnetically-suspended motion control system are presented in this paper. Noise sources in the transducers, electronics, and mechanical vibrations are used to develop the control design.

  6. Automatic co-registration of space-based sensors for precision change detection and analysis

    NASA Technical Reports Server (NTRS)

    Bryant, N.; Zobrist, A.; Logan, T.

    2003-01-01

    A variety of techniques were developed at JPL to assure sub-pixel co-registration of scenes and ortho-rectification of satellite imagery to other georeferenced information to permit precise change detection and analysis of low and moderate resolution space sensors.

  7. Automatic co-registration of space-based sensors for precision change detection and analysis

    NASA Technical Reports Server (NTRS)

    Bryant, N.; Zobrist, A.; Logan, T.

    2003-01-01

    A variety of techniques were developed at JPL to assure sub-pixel co-registration of scenes and ortho-rectification of satellite imagery to other georeferenced information to permit precise change detection and analysis of low and moderate resolution space sensors.

  8. Universal, computer facilitated, steady state oscillator, closed loop analysis theory and some applications to precision oscillators

    NASA Technical Reports Server (NTRS)

    Parzen, Benjamin

    1992-01-01

    The theory of oscillator analysis in the immittance domain should be read in conjunction with the additional theory presented here. The combined theory enables the computer simulation of the steady state oscillator. The simulation makes the calculation of the oscillator total steady state performance practical, including noise at all oscillator locations. Some specific precision oscillators are analyzed.

  9. Up-to-date and precise estimates of cancer patient survival: model-based period analysis.

    PubMed

    Brenner, Hermann; Hakulinen, Timo

    2006-10-01

    Monitoring of progress in cancer patient survival by cancer registries should be as up-to-date as possible. Period analysis has been shown to provide more up-to-date survival estimates than do traditional methods of survival analysis. However, there is a trade-off between up-to-dateness and the precision of period estimates, in that increasing the up-to-dateness of survival estimates by restricting the analysis to a relatively short, recent time period, such as the most recent calendar year for which cancer registry data are available, goes along with a loss of precision. The authors propose a model-based approach to maximize the up-to-dateness of period estimates at minimal loss of precision. The approach is illustrated for monitoring of 5-year relative survival of patients diagnosed with one of 20 common forms of cancer in Finland between 1953 and 2002 by use of data from the nationwide Finnish Cancer Registry. It is shown that the model-based approach provides survival estimates that are as up-to-date as the most up-to-date conventional period estimates and at the same time much more precise than the latter. The modeling approach may further enhance the use of period analysis for deriving up-to-date cancer survival rates.

  10. Effect of Body Structure on Skill Formation in a Force Precision Task Mimicking Cello Bowing Movement

    NASA Astrophysics Data System (ADS)

    Ogihara, Naomichi; Yamazaki, Nobutoshi

    To elucidate the skill formation mechanism in a complex force precision task mimicking cello bowing movements, three-dimensional joint orientations and changes in bowing force are measured for 2 novice and 2 expert subjects. A rigid link model of the human upper limb is constructed in order to calculate changes in joint moment, potential energy and structural inductivity of motion during bowing, and the motions are compared kinetically. Results show that the novices generate low-in-potential energy bowing motion, but not suitable for skillful control of the bow. In contrast, the experts can fulfill a task requirement by skillfully coordinating the musculo-skeletal system, but the motion is not easy as that of the novices. It is suggested that the transition from a novice to an expert may be difficult due to the ease in the initially generated motion, which obstructs the search for the optimal skillful motion.

  11. Towards precise defect control in layered oxide structures by using oxide molecular beam epitaxy

    PubMed Central

    Baiutti, Federico; Christiani, Georg

    2014-01-01

    Summary In this paper we present the atomic-layer-by-layer oxide molecular beam epitaxy (ALL-oxide MBE) which has been recently installed in the Max-Planck Institute for Solid State Research and we report on its present status, providing some examples that demonstrate its successful application in the synthesis of different layered oxides, with particular reference to superconducting La2CuO4 and insulator-to-metal La2− xSrxNiO4. We briefly review the ALL-oxide MBE technique and its unique capabilities in the deposition of atomically smooth single-crystal thin films of various complex oxides, artificial compounds and heterostructures, introducing our goal of pursuing a deep investigation of such systems with particular emphasis on structural defects, with the aim of tailoring their functional properties by precise defects control. PMID:24995148

  12. Towards precise defect control in layered oxide structures by using oxide molecular beam epitaxy.

    PubMed

    Baiutti, Federico; Christiani, Georg; Logvenov, Gennady

    2014-01-01

    In this paper we present the atomic-layer-by-layer oxide molecular beam epitaxy (ALL-oxide MBE) which has been recently installed in the Max-Planck Institute for Solid State Research and we report on its present status, providing some examples that demonstrate its successful application in the synthesis of different layered oxides, with particular reference to superconducting La2CuO4 and insulator-to-metal La2- x Sr x NiO4. We briefly review the ALL-oxide MBE technique and its unique capabilities in the deposition of atomically smooth single-crystal thin films of various complex oxides, artificial compounds and heterostructures, introducing our goal of pursuing a deep investigation of such systems with particular emphasis on structural defects, with the aim of tailoring their functional properties by precise defects control.

  13. Precise earthquake locations show evidence of internal structures at intermediate-depth earthquake nests

    NASA Astrophysics Data System (ADS)

    Prieto, G.; Florez, M.; Dionicio, V.; Barrett, S. A.; Beroza, G. C.

    2012-12-01

    The mechanism for intermediate depth and deep earthquakes is still under debate. The temperatures and pressures are above the point where ordinary fractures ought to occur. Earthquake nests are regions of highly concentrated seismicity within subducting lithosphere that are isolated from nearby activity and may be key in revealing the mechanics of intermediate-depth earthquakes. We present precise earthquake locations of intermediate-depth earthquakes in the Bucaramanga nest, Colombia using double-difference algorithms combined with depth phases recorded at regional and teleseismic distances. Our results show an alignment of seismicity along subhorizontal and/or subvertical regions within the nest and a preferential location of larger earthquakes at the bottom of the cluster. These observed features might suggest preexisting structures within the subducting slab or some process that allows concentration of deformation and repeating ruptures along fractures.

  14. Construction of a versatile high precision ambient ionization source for direct analysis and imaging.

    PubMed

    Sampson, Jason S; Hawkridge, Adam M; Muddiman, David C

    2008-10-01

    The design and construction of a high precision ambient ionization source matrix-assisted laser desorption electrospray ionization (MALDESI) are described in full detail, including a complete parts list. The computer controlled high precision motion control system and high repetition rate Explorer laser are demonstrated during MALDESI-FT-ICR analysis of peptides and proteins ranging from 1 to 17 kDa. The high stability ionization source platform described herein demonstrates both the advantages of the new MALDESI source and versatility for application to numerous desorption and ionization techniques.

  15. Writing with Fluid: Structuring Hydrogels with Micrometer Precision by AFM in Combination with Nanofluidics.

    PubMed

    Helfricht, Nicolas; Mark, Andreas; Behr, Marina; Bernet, Andreas; Schmidt, Hans-Werner; Papastavrou, Georg

    2017-08-01

    Hydrogels have many applications in biomedical surface modification and tissue engineering. However, the structuring of hydrogels after their formation represents still a major challenge, in particular due to their softness. Here, a novel approach is presented that is based on the combination of atomic force microscopy (AFM) and nanofluidics, also referred to as FluidFM technology. Its applicability is demonstrated for supramolecular hydrogel films that are prepared from low-molecular weight hydrogelators, such as derivates of 1,3,5-benzene tricarboxamides (BTAs). BTA films can be dissolved selectively by ejecting alkaline solution through the aperture of a hollow AFM-cantilever connected to a nanofluidic controller. The AFM-based force control is essential in preventing mechanical destruction of the hydrogels. The resulting "chemical writing" process is studied in detail and the influence of various parameters, such as applied pressure and time, is validated. It is demonstrated that the achievable structuring precision is primarily limited by diffusion and the aperture dimensions. Recently, various additive techniques have been presented to pattern hydrogels. The here-presented subtractive approach can not only be applied to structure hydrogels from the large class of reversibly formed gels with superior resolution but would also allow for the selective loading of the hydrogels with active substances or nanoparticles. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Precise structure control of three-state nanomechanical DNA origami devices.

    PubMed

    Kuzuya, Akinori; Watanabe, Ryosuke; Hashizume, Mirai; Kaino, Masafumi; Minamida, Shinya; Kameda, Koji; Ohya, Yuichi

    2014-05-15

    Precise structure switching between all of the three forms of three-state nanomechanical DNA origami devices has been accomplished. A nanomechanical DNA origami device called DNA origami pliers, which consists of two levers of 170-nm long, 20-nm wide, and 2-nm thick connected at a Holliday-junction fulcrum, takes three conformations: closed parallel, closed antiparallel, and open cross forms. They were previously applied to construct detection systems for biomolecules in single-molecular resolution by observing the structure switching between cross form and one of the other two forms under atomic force microscope (AFM). We redesigned DNA origami pliers in this study to let them freely switch between all of the three states including parallel-antiparallel direct switching without taking cross form. By the addition of appropriate switcher strands to the solution, hybridization and dehybridization of particular binder strands that fix the levers into predetermined state were selectively triggered as programmed in their sequence. Circuit structure switching through all of the three states in both of the two opposite direction was even successful with the new design. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Precise and Reversible Protein-Microtubule-Like Structure with Helicity Driven by Dual Supramolecular Interactions.

    PubMed

    Yang, Guang; Zhang, Xiang; Kochovski, Zdravko; Zhang, Yufei; Dai, Bin; Sakai, Fuji; Jiang, Lin; Lu, Yan; Ballauff, Matthias; Li, Xueming; Liu, Cong; Chen, Guosong; Jiang, Ming

    2016-02-17

    Protein microtubule is a significant self-assembled architecture found in nature with crucial biological functions. However, mimicking protein microtubules with precise structure and controllable self-assembly behavior remains highly challenging. In this work, we demonstrate that by using dual supramolecular interactions from a series of well-designed ligands, i.e., protein-sugar interaction and π-π stacking, highly homogeneous protein microtubes were achieved from tetrameric soybean agglutinin without any chemical or biological modification. Using combined cryo-EM single-particle reconstruction and computational modeling, the accurate structure of protein microtube was determined. The helical protein microtube is consisted of three protofilaments, each of which features an array of soybean agglutinin tetramer linked by the designed ligands. Notably, the microtubes resemble the natural microtubules in their structural and dynamic features such as the shape and diameter and the controllable and reversible assembly behavior, among others. Furthermore, the protein microtubes showed an ability to enhance immune response, demonstrating its great potential for biological applications.

  18. Effectiveness of Spectral Similarity Measures to Develop Precise Crop Spectra for Hyperspectral Data Analysis

    NASA Astrophysics Data System (ADS)

    Chauhan, H.; Krishna Mohan, B.

    2014-11-01

    The present study was undertaken with the objective to check effectiveness of spectral similarity measures to develop precise crop spectra from the collected hyperspectral field spectra. In Multispectral and Hyperspectral remote sensing, classification of pixels is obtained by statistical comparison (by means of spectral similarity) of known field or library spectra to unknown image spectra. Though these algorithms are readily used, little emphasis has been placed on use of various spectral similarity measures to select precise crop spectra from the set of field spectra. Conventionally crop spectra are developed after rejecting outliers based only on broad-spectrum analysis. Here a successful attempt has been made to develop precise crop spectra based on spectral similarity. As unevaluated data usage leads to uncertainty in the image classification, it is very crucial to evaluate the data. Hence, notwithstanding the conventional method, the data precision has been performed effectively to serve the purpose of the present research work. The effectiveness of developed precise field spectra was evaluated by spectral discrimination measures and found higher discrimination values compared to spectra developed conventionally. Overall classification accuracy for the image classified by field spectra selected conventionally is 51.89% and 75.47% for the image classified by field spectra selected precisely based on spectral similarity. KHAT values are 0.37, 0.62 and Z values are 2.77, 9.59 for image classified using conventional and precise field spectra respectively. Reasonable higher classification accuracy, KHAT and Z values shows the possibility of a new approach for field spectra selection based on spectral similarity measure.

  19. Structural analysis of glucans

    PubMed Central

    Novak, Miroslav

    2014-01-01

    Glucans are most widespread polysaccharides in the nature. There is a large diversity in their molecular weight and configuration depending on the original source. According to the anomeric structure of glucose units it is possible to distinguish linear and branched α-, β- as well as mixed α,β-glucans with various glycoside bond positions and molecular masses. Isolation of glucans from raw sources needs removal of ballast compounds including proteins, lipids, polyphenols and other polysaccharides. Purity control of glucan fractions is necessary to evaluate the isolation and purification steps; more rigorous structural analyses of purified polysaccharides are required to clarify their structure. A set of spectroscopic, chemical and separation methods are used for this purpose. Among them, NMR spectroscopy is known as a powerful tool in structural analysis of glucans both in solution and in solid state. Along with chemolytic methods [methylation analysis (MA), periodate oxidation, partial chemical or enzymatic hydrolysis, etc.], correlation NMR experiments are able to determine the exact structure of tested polysaccharides. Vibration spectroscopic methods (FTIR, Raman) are sensitive to anomeric structure of glucans and can be used for purity control as well. Molecular weight distribution, homogeneity and branching of glucans can be estimated by size-exclusion chromatography (SEC), laser light scattering (LLS) and viscometry. PMID:25332993

  20. Characteristic evaluation and experimental analysis of the ultrahigh precision three-dimensional scanning probe

    NASA Astrophysics Data System (ADS)

    Liu, Shuai; Xue, Zi; Ye, Shu-liang; Hou, Dexin; Wang, He-yan

    2013-01-01

    Probe is the kernel component of the precision measuring instrument for the system accuracy which is determined by the probe characteristic. Three-dimensional scanning probe is an ideal choice for gear helical error measurement because it has both space coordinates points detecting capacity and scan capacity on the space of curves and surfaces. In order to make full use of the probe's capacity and improve the measurement accuracy, characteristic evaluation of the probe is necessary before used. The static calibration equipment for the sensor has been established based on the high precision PZT micro displacement platform. Linear characteristic analysis and compensate of the ultra-high precision three-dimensional scanning probe has been done by this equipment, which greatly improved the accuracy of the probe. Finally, probe characteristic under working status is analyzed and experimentally verified which will be very helpful to compensate the probe errors.

  1. Frontiers of QC Laser spectroscopy for high precision isotope ratio analysis of greenhouse gases

    NASA Astrophysics Data System (ADS)

    Emmenegger, Lukas; Mohn, Joachim; Harris, Eliza; Eyer, Simon; Ibraim, Erkan; Tuzson, Béla

    2016-04-01

    An important milestone for laser spectroscopy was achieved when isotope ratios of greenhouse gases were reported at precision levels that allow addressing research questions in environmental sciences. Real-time data with high temporal resolution at moderate cost and instrument size make the optical approach highly attractive, complementary to the well-established isotope-ratio mass-spectrometry (IRMS) method. Especially appealing, in comparison to IRMS, is the inherent specificity to structural isomers having the same molecular mass. Direct absorption in the MIR in single or dual QCL configuration has proven highly reliable for the sta-ble isotopes of CO2, N2O and CH4. The longest time series of real-time measurements is currently available for δ13C and δ18O in CO2 at the high-alpine station Jung-fraujoch. At this well-equipped site, QCL based direct absorption spectroscopy (QCLAS) measurements are ongoing since 2008 1,2. Applications of QCLAS for N2O and CH4 stable isotopes are considerably more challenging because of the lower atmospheric mixing ratios, especially for the less abundant species, such as N218O and CH3D. For high precision (< 0.1 ‰) measurements in ambient air, QCLAS may be combined with a fully automated preconcentration unit yielding an up to 500 times concentration increase and the capability to separate the target gas from spectral interferants by se-quential desorption 3. Here, we review our recent developments on high precision isotope ratio analysis of greenhouse gases, with special focus on the isotopic species of N2O and CH4. Furthermore, we show environ-mental applications illustrating the highly valuable information that isotope ratios of atmospheric trace gases can carry. For example, the intramolecular distribution of 15N in N2O gives important information on the geochemical cycle of N2O4-6, while the analysis of δ13C and δ D in CH4 may be applied to disentangle microbial, fossil and landfill sources 7. 1 Sturm, P., Tuzson, B

  2. High-precision limit on variation in the fine-structure constant from a single quasar absorption system

    NASA Astrophysics Data System (ADS)

    Kotuš, S. M.; Murphy, M. T.; Carswell, R. F.

    2017-01-01

    The brightest southern quasar above redshift z = 1, HE 0515-4414, with its strong intervening metal absorption line system at zabs = 1.1508, provides a unique opportunity to precisely measure or limit relative variations in the fine-structure constant (Δα/α). A variation of just ˜3 parts per million (ppm) would produce detectable velocity shifts between its many strong metal transitions. Using new and archival observations from the Ultraviolet and Visual Echelle Spectrograph (UVES), we obtain an extremely high signal-to-noise ratio spectrum (peaking at S/N ≈ 250 pix-1). This provides the most precise measurement of Δα/α from a single absorption system to date, Δα/α = -1.42 ± 0.55stat ± 0.65sys ppm, comparable with the precision from previous, large samples of ˜150 absorbers. The largest systematic error in all (but one) previous similar measurements, including the large samples, was long-range distortions in the wavelength calibration. These would add an ˜2 ppm systematic error to our measurement and up to ˜10 ppm to other measurements using Mg and Fe transitions. However, we corrected the UVES spectra using well-calibrated spectra of the same quasar from the High Accuracy Radial velocity Planet Searcher, leaving a residual 0.59 ppm systematic uncertainty, the largest contribution to our total systematic error. A similar approach, using short observations on future well-calibrated spectrographs to correct existing high S/N spectra, would efficiently enable a large sample of reliable Δα/α measurements. The high-S/N UVES spectrum also provides insights into analysis difficulties, detector artefacts and systematic errors likely to arise from 25-40-m telescopes.

  3. Design oriented structural analysis

    NASA Technical Reports Server (NTRS)

    Giles, Gary L.

    1994-01-01

    Desirable characteristics and benefits of design oriented analysis methods are described and illustrated by presenting a synoptic description of the development and uses of the Equivalent Laminated Plate Solution (ELAPS) computer code. ELAPS is a design oriented structural analysis method which is intended for use in the early design of aircraft wing structures. Model preparation is minimized by using a few large plate segments to model the wing box structure. Computational efficiency is achieved by using a limited number of global displacement functions that encompass all segments over the wing planform. Coupling with other codes is facilitated since the output quantities such as deflections and stresses are calculated as continuous functions over the plate segments. Various aspects of the ELAPS development are discussed including the analytical formulation, verification of results by comparison with finite element analysis results, coupling with other codes, and calculation of sensitivity derivatives. The effectiveness of ELAPS for multidisciplinary design application is illustrated by describing its use in design studies of high speed civil transport wing structures.

  4. Location precision analysis of stereo thermal anti-sniper detection system

    NASA Astrophysics Data System (ADS)

    He, Yuqing; Lu, Ya; Zhang, Xiaoyan; Jin, Weiqi

    2012-06-01

    Anti-sniper detection devices are the urgent requirement in modern warfare. The precision of the anti-sniper detection system is especially important. This paper discusses the location precision analysis of the anti-sniper detection system based on the dual-thermal imaging system. It mainly discusses the following two aspects which produce the error: the digital quantitative effects of the camera; effect of estimating the coordinate of bullet trajectory according to the infrared images in the process of image matching. The formula of the error analysis is deduced according to the method of stereovision model and digital quantitative effects of the camera. From this, we can get the relationship of the detecting accuracy corresponding to the system's parameters. The analysis in this paper provides the theory basis for the error compensation algorithms which are put forward to improve the accuracy of 3D reconstruction of the bullet trajectory in the anti-sniper detection devices.

  5. The Price of Precision: Large-Scale Mapping of Forest Structure and Biomass Using Airborne Lidar

    NASA Astrophysics Data System (ADS)

    Dubayah, R.

    2015-12-01

    Lidar remote sensing provides one of the best means for acquiring detailed information on forest structure. However, its application over large areas has been limited largely because of its expense. Nonetheless, extant data exist over many states in the U.S., funded largely by state and federal consortia and mainly for infrastructure, emergency response, flood plain and coastal mapping. These lidar data are almost always acquired in leaf-off seasons, and until recently, usually with low point count densities. Even with these limitations, they provide unprecedented wall-to-wall mappings that enable development of appropriate methodologies for large-scale deployment of lidar. In this talk we summarize our research and lessons learned in deriving forest structure over regional areas as part of NASA's Carbon Monitoring System (CMS). We focus on two areas: the entire state of Maryland and Sonoma County, California. The Maryland effort used low density, leaf-off data acquired by each county in varying epochs, while the on-going Sonoma work employs state-of-the-art, high density, wall-to-wall, leaf-on lidar data. In each area we combine these lidar coverages with high-resolution multispectral imagery from the National Agricultural Imagery Program (NAIP) and in situ plot data to produce maps of canopy height, tree cover and biomass, and compare our results against FIA plot data and national biomass maps. Our work demonstrates that large-scale mapping of forest structure at high spatial resolution is achievable but products may be complex to produce and validate over large areas. Furthermore, fundamental issues involving statistical approaches, plot types and sizes, geolocation, modeling scales, allometry, and even the definitions of "forest" and "non-forest" must be approached carefully. Ultimately, determining the "price of precision", that is, does the value of wall-to-wall forest structure data justify their expense, should consider not only carbon market applications

  6. The cancer precision medicine knowledge base for structured clinical-grade mutations and interpretations

    PubMed Central

    Huang, Linda; Fernandes, Helen; Zia, Hamid; Tavassoli, Peyman; Rennert, Hanna; Pisapia, David; Imielinski, Marcin; Sboner, Andrea; Rubin, Mark A; Kluk, Michael

    2017-01-01

    Objective: This paper describes the Precision Medicine Knowledge Base (PMKB; https://pmkb.weill.cornell.edu), an interactive online application for collaborative editing, maintenance, and sharing of structured clinical-grade cancer mutation interpretations. Materials and Methods: PMKB was built using the Ruby on Rails Web application framework. Leveraging existing standards such as the Human Genome Variation Society variant description format, we implemented a data model that links variants to tumor-specific and tissue-specific interpretations. Key features of PMKB include support for all major variant types, standardized authentication, distinct user roles including high-level approvers, and detailed activity history. A REpresentational State Transfer (REST) application-programming interface (API) was implemented to query the PMKB programmatically. Results: At the time of writing, PMKB contains 457 variant descriptions with 281 clinical-grade interpretations. The EGFR, BRAF, KRAS, and KIT genes are associated with the largest numbers of interpretable variants. PMKB’s interpretations have been used in over 1500 AmpliSeq tests and 750 whole-exome sequencing tests. The interpretations are accessed either directly via the Web interface or programmatically via the existing API. Discussion: An accurate and up-to-date knowledge base of genomic alterations of clinical significance is critical to the success of precision medicine programs. The open-access, programmatically accessible PMKB represents an important attempt at creating such a resource in the field of oncology. Conclusion: The PMKB was designed to help collect and maintain clinical-grade mutation interpretations and facilitate reporting for clinical cancer genomic testing. The PMKB was also designed to enable the creation of clinical cancer genomics automated reporting pipelines via an API. PMID:27789569

  7. The cancer precision medicine knowledge base for structured clinical-grade mutations and interpretations.

    PubMed

    Huang, Linda; Fernandes, Helen; Zia, Hamid; Tavassoli, Peyman; Rennert, Hanna; Pisapia, David; Imielinski, Marcin; Sboner, Andrea; Rubin, Mark A; Kluk, Michael; Elemento, Olivier

    2017-05-01

    This paper describes the Precision Medicine Knowledge Base (PMKB; https://pmkb.weill.cornell.edu ), an interactive online application for collaborative editing, maintenance, and sharing of structured clinical-grade cancer mutation interpretations. PMKB was built using the Ruby on Rails Web application framework. Leveraging existing standards such as the Human Genome Variation Society variant description format, we implemented a data model that links variants to tumor-specific and tissue-specific interpretations. Key features of PMKB include support for all major variant types, standardized authentication, distinct user roles including high-level approvers, and detailed activity history. A REpresentational State Transfer (REST) application-programming interface (API) was implemented to query the PMKB programmatically. At the time of writing, PMKB contains 457 variant descriptions with 281 clinical-grade interpretations. The EGFR, BRAF, KRAS, and KIT genes are associated with the largest numbers of interpretable variants. PMKB's interpretations have been used in over 1500 AmpliSeq tests and 750 whole-exome sequencing tests. The interpretations are accessed either directly via the Web interface or programmatically via the existing API. An accurate and up-to-date knowledge base of genomic alterations of clinical significance is critical to the success of precision medicine programs. The open-access, programmatically accessible PMKB represents an important attempt at creating such a resource in the field of oncology. The PMKB was designed to help collect and maintain clinical-grade mutation interpretations and facilitate reporting for clinical cancer genomic testing. The PMKB was also designed to enable the creation of clinical cancer genomics automated reporting pipelines via an API.

  8. Structural dynamics analysis

    NASA Astrophysics Data System (ADS)

    Housner, J. M.; Anderson, M.; Belvin, W.; Horner, G.

    1985-04-01

    Dynamic analysis of large space antenna systems must treat the deployment as well as vibration and control of the deployed antenna. Candidate computer programs for deployment dynamics, and issues and needs for future program developments are reviewed. Some results for mast and hoop deployment are also presented. Modeling of complex antenna geometry with conventional finite element methods and with repetitive exact elements is considered. Analytical comparisons with experimental results for a 15 meter hoop/column antenna revealed the importance of accurate structural properties including nonlinear joints. Slackening of cables in this antenna is also a consideration. The technology of designing actively damped structures through analytical optimization is discussed and results are presented.

  9. Structural dynamics analysis

    NASA Technical Reports Server (NTRS)

    Housner, J. M.; Anderson, M.; Belvin, W.; Horner, G.

    1985-01-01

    Dynamic analysis of large space antenna systems must treat the deployment as well as vibration and control of the deployed antenna. Candidate computer programs for deployment dynamics, and issues and needs for future program developments are reviewed. Some results for mast and hoop deployment are also presented. Modeling of complex antenna geometry with conventional finite element methods and with repetitive exact elements is considered. Analytical comparisons with experimental results for a 15 meter hoop/column antenna revealed the importance of accurate structural properties including nonlinear joints. Slackening of cables in this antenna is also a consideration. The technology of designing actively damped structures through analytical optimization is discussed and results are presented.

  10. Precision mechanical structure of an ultra-high-resolution spectrometer for inelastic X-ray scattering instrument

    DOEpatents

    Shu, Deming; Shvydko, Yuri; Stoupin, Stanislav A.; Khachatryan, Ruben; Goetze, Kurt A.; Roberts, Timothy

    2015-04-14

    A method and an ultrahigh-resolution spectrometer including a precision mechanical structure for positioning inelastic X-ray scattering optics are provided. The spectrometer includes an X-ray monochromator and an X-ray analyzer, each including X-ray optics of a collimating (C) crystal, a pair of dispersing (D) element crystals, anomalous transmission filter (F) and a wavelength (W) selector crystal. A respective precision mechanical structure is provided with the X-ray monochromator and the X-ray analyzer. The precision mechanical structure includes a base plate, such as an aluminum base plate; positioning stages for D-crystal alignment; positioning stages with an incline sensor for C/F/W-crystal alignment, and the positioning stages including flexure-based high-stiffness structure.

  11. The Effect of Quantum-Mechanical Interference on Precise Measurements of the n = 2 Triplet P Fine Structure of Helium

    SciTech Connect

    Marsman, A.; Horbatsch, M.; Hessels, E. A.

    2015-09-15

    For many decades, improvements in both theory and experiment of the fine structure of the n = 2 triplet P levels of helium have allowed for an increasingly precise determination of the fine-structure constant. Recently, it has been observed that quantum-mechanical interference between neighboring resonances can cause significant shifts, even if such neighboring resonances are separated by thousands of natural widths. The shifts depend in detail on the experimental method used for the measurement, as well as the specific experimental parameters employed. Here, we review how these shifts apply for the most precise measurements of the helium 2{sup 3}P fine-structure intervals.

  12. Micro-precision control/structure interaction technology for large optical space systems

    NASA Technical Reports Server (NTRS)

    Sirlin, Samuel W.; Laskin, Robert A.

    1993-01-01

    The CSI program at JPL is chartered to develop the structures and control technology needed for sub-micron level stabilization of future optical space systems. The extreme dimensional stability required for such systems derives from the need to maintain the alignment and figure of critical optical elements to a small fraction (typically 1/20th to 1/50th) of the wavelength of detected radiation. The wavelength is about 0.5 micron for visible light and 0.1 micron for ultra-violet light. This lambda/50 requirement is common to a broad class of optical systems including filled aperture telescopes (with monolithic or segmented primary mirrors), sparse aperture telescopes, and optical interferometers. The challenge for CSI arises when such systems become large, with spatially distributed optical elements mounted on a lightweight, flexible structure. In order to better understand the requirements for micro-precision CSI technology, a representative future optical system was identified and developed as an analytical testbed for CSI concepts and approaches. An optical interferometer was selected as a stressing example of the relevant mission class. The system that emerged was termed the Focus Mission Interferometer (FMI). This paper will describe the multi-layer control architecture used to address the FMI's nanometer level stabilization requirements. In addition the paper will discuss on-going and planned experimental work aimed at demonstrating that multi-layer CSI can work in practice in the relevant performance regime.

  13. Micro-Precision Interferometer Testbed: end-to-end system integration of control structure interaction technologies

    NASA Astrophysics Data System (ADS)

    Neat, Gregory W.; Sword, Lee F.; Hines, Braden E.; Calvet, Robert J.

    1993-09-01

    This paper describes the overall design and planned phased delivery of the ground-based Micro-Precision Interferometer (MPI) Testbed. The testbed is a half scale replica of a future space-based interferometer containing all the spacecraft subsystems necessary to perform an astrometric measurement. Appropriate sized reaction wheels will regulate the testbed attitude as well as provide a flight-like disturbance source. The optical system will consist of two complete Michelson interferometers. Successful interferometric measurements require controlling the positional stabilities of these optical elements to the nanometer level. The primary objective of the testbed is to perform a system integration of Control Structure Interaction (CSI) technologies necessary to demonstrate the end-to-end operation of a space- based interferometer, ultimately proving to flight mission planners that the necessary control technology exists to meet the challenging requirements of future space-based interferometry missions. These technologies form a multi-layered vibration attenuation architecture to achieve the necessary quiet environment. This three layered methodology blends disturbance isolation, structural quieting and active optical control techniques. The paper describes all the testbed subsystems in this end-to-end ground-based system as well as the present capabilities of the evolving testbed.

  14. Precise Truss Assembly Using Commodity Parts and Low Precision Welding

    NASA Technical Reports Server (NTRS)

    Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, W. R.; Correll, Nikolaus

    2014-01-01

    Hardware and software design and system integration for an intelligent precision jigging robot (IPJR), which allows high precision assembly using commodity parts and low-precision bonding, is described. Preliminary 2D experiments that are motivated by the problem of assembling space telescope optical benches and very large manipulators on orbit using inexpensive, stock hardware and low-precision welding are also described. An IPJR is a robot that acts as the precise "jigging", holding parts of a local structure assembly site in place, while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (for this prototype, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. The analysis of the assembly error and the results of building a square structure and a ring structure are discussed. Options for future work, to extend the IPJR paradigm to building in 3D structures at micron precision are also summarized.

  15. Precise Truss Assembly Using Commodity Parts and Low Precision Welding

    NASA Technical Reports Server (NTRS)

    Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, W. R.; Correll, Nikolaus

    2014-01-01

    Hardware and software design and system integration for an intelligent precision jigging robot (IPJR), which allows high precision assembly using commodity parts and low-precision bonding, is described. Preliminary 2D experiments that are motivated by the problem of assembling space telescope optical benches and very large manipulators on orbit using inexpensive, stock hardware and low-precision welding are also described. An IPJR is a robot that acts as the precise "jigging", holding parts of a local structure assembly site in place, while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (for this prototype, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. The analysis of the assembly error and the results of building a square structure and a ring structure are discussed. Options for future work, to extend the IPJR paradigm to building in 3D structures at micron precision are also summarized.

  16. High-precision image aided inertial navigation with known features: observability analysis and performance evaluation.

    PubMed

    Jiang, Weiping; Wang, Li; Niu, Xiaoji; Zhang, Quan; Zhang, Hui; Tang, Min; Hu, Xiangyun

    2014-10-17

    A high-precision image-aided inertial navigation system (INS) is proposed as an alternative to the carrier-phase-based differential Global Navigation Satellite Systems (CDGNSSs) when satellite-based navigation systems are unavailable. In this paper, the image/INS integrated algorithm is modeled by a tightly-coupled iterative extended Kalman filter (IEKF). Tightly-coupled integration ensures that the integrated system is reliable, even if few known feature points (i.e., less than three) are observed in the images. A new global observability analysis of this tightly-coupled integration is presented to guarantee that the system is observable under the necessary conditions. The analysis conclusions were verified by simulations and field tests. The field tests also indicate that high-precision position (centimeter-level) and attitude (half-degree-level)-integrated solutions can be achieved in a global reference.

  17. High-Precision Image Aided Inertial Navigation with Known Features: Observability Analysis and Performance Evaluation

    PubMed Central

    Jiang, Weiping; Wang, Li; Niu, Xiaoji; Zhang, Quan; Zhang, Hui; Tang, Min; Hu, Xiangyun

    2014-01-01

    A high-precision image-aided inertial navigation system (INS) is proposed as an alternative to the carrier-phase-based differential Global Navigation Satellite Systems (CDGNSSs) when satellite-based navigation systems are unavailable. In this paper, the image/INS integrated algorithm is modeled by a tightly-coupled iterative extended Kalman filter (IEKF). Tightly-coupled integration ensures that the integrated system is reliable, even if few known feature points (i.e., less than three) are observed in the images. A new global observability analysis of this tightly-coupled integration is presented to guarantee that the system is observable under the necessary conditions. The analysis conclusions were verified by simulations and field tests. The field tests also indicate that high-precision position (centimeter-level) and attitude (half-degree-level)-integrated solutions can be achieved in a global reference. PMID:25330046

  18. August Dvorak (1894-1975): Early expressions of applied behavior analysis and precision teaching

    PubMed Central

    Joyce, Bonnie; Moxley, Roy A.

    1988-01-01

    August Dvorak is best known for his development of the Dvorak keyboard. However, Dvorak also adapted and applied many behavioral and scientific management techniques to the field of education. Taken collectively, these techniques are representative of many of the procedures currently used in applied behavior analysis, in general, and especially in precision teaching. The failure to consider Dvorak's instructional methods may explain some of the discrepant findings in studies which compare the efficiency of the Dvorak to the standard keyboard. This article presents a brief background on the development of the standard (QWERTY) and Dvorak keyboards, describes parallels between Dvorak's teaching procedures and those used in precision teaching, reviews some of the comparative research on the Dvorak keyboard, and suggests some implications for further research in applying the principles of behavior analysis. PMID:22477993

  19. August Dvorak (1894-1975): Early expressions of applied behavior analysis and precision teaching.

    PubMed

    Joyce, B; Moxley, R A

    1988-01-01

    August Dvorak is best known for his development of the Dvorak keyboard. However, Dvorak also adapted and applied many behavioral and scientific management techniques to the field of education. Taken collectively, these techniques are representative of many of the procedures currently used in applied behavior analysis, in general, and especially in precision teaching. The failure to consider Dvorak's instructional methods may explain some of the discrepant findings in studies which compare the efficiency of the Dvorak to the standard keyboard. This article presents a brief background on the development of the standard (QWERTY) and Dvorak keyboards, describes parallels between Dvorak's teaching procedures and those used in precision teaching, reviews some of the comparative research on the Dvorak keyboard, and suggests some implications for further research in applying the principles of behavior analysis.

  20. Accounting for Limited Detection Efficiency and Localization Precision in Cluster Analysis in Single Molecule Localization Microscopy

    PubMed Central

    Shivanandan, Arun; Unnikrishnan, Jayakrishnan; Radenovic, Aleksandra

    2015-01-01

    Single Molecule Localization Microscopy techniques like PhotoActivated Localization Microscopy, with their sub-diffraction limit spatial resolution, have been popularly used to characterize the spatial organization of membrane proteins, by means of quantitative cluster analysis. However, such quantitative studies remain challenged by the techniques’ inherent sources of errors such as a limited detection efficiency of less than 60%, due to incomplete photo-conversion, and a limited localization precision in the range of 10 – 30nm, varying across the detected molecules, mainly depending on the number of photons collected from each. We provide analytical methods to estimate the effect of these errors in cluster analysis and to correct for them. These methods, based on the Ripley’s L(r) – r or Pair Correlation Function popularly used by the community, can facilitate potentially breakthrough results in quantitative biology by providing a more accurate and precise quantification of protein spatial organization. PMID:25794150

  1. A simple and precise method for quantitative analysis of lumefantrine by planar chromatography

    PubMed Central

    Hamrapurkar, Purnima; Phale, Mitesh; Pawar, Sandeep; Patil, Priti; Gandhi, Mittal

    2010-01-01

    A simple, precise and sensitive high performance thin layer chromatographic (HPTLC) method has been developed and validated for drug of choice Lumefantrine in treatment of malaria (P. falciparum). Silica gel 60 F254 HPTLC precoated plates were used for quantitative analytical purpose. Methanol water 9.5 + 0.5 (v/v) was used as the solvent system. Densitometric scanning was carried out with deuterium lamp set at detection wavelength of 266 nm. The response to lumefantrine concentration was linear in the concentration range of 1.25-12.50 μg/ml. The suitability of the method developed and validated was in accordance with the requirements of the ICH guidelines (Q2B). Thus the validated method can be further applied to quantitative analysis of lumefantrine in commercial pharmaceutical dosage form. The proposed method is simple, sensitive, precise and accurate, confirming its pharmaceutical application in routine quality control analysis. PMID:23781415

  2. Precision analysis of a multi-slice ultrasound sensor for non-invasive 3D kinematic analysis of knee joints.

    PubMed

    Masum, Md Abdullah; Lambert, Andrew J; Pickering, Mark R; Scarvell, J M; Smith, P N

    2012-01-01

    Currently the standard clinical practice for measuring the motion of bones in a knee joint with sufficient precision involves implanting tantalum beads into the bones to act as fiducial markers prior to imaging using X-ray equipment. This procedure is invasive in nature and exposure to ionizing radiation imposes a cancer risk and the patient's movements are confined to a narrow field of view. In this paper, an ultrasound based system for non-invasive kinematic evaluation of knee joints is proposed. The results of an initial analysis show that this system can provide the precision required for non-invasive motion analysis while the patient performs normal physical activities.

  3. Ultra-low-molecular-weight heparins: precise structural features impacting specific anticoagulant activities.

    PubMed

    Lima, Marcelo A; Viskov, Christian; Herman, Frederic; Gray, Angel L; de Farias, Eduardo H C; Cavalheiro, Renan P; Sassaki, Guilherme L; Hoppensteadt, Debra; Fareed, Jawed; Nader, Helena B

    2013-03-01

    Ultra-low-molecular-weight heparins (ULMWHs) with better efficacy and safety ratios are under development; however, there are few structural data available. The main structural features and molecular weight of ULMWHs were studied and compared to enoxaparin. Their monosaccharide composition and average molecular weights were determined and preparations studied by nuclear magnetic resonance spectroscopy, scanning ultraviolet spectroscopy, circular dichroism and gel permeation chromatography. In general, ULMWHs presented higher 3-O-sulphated glucosamine and unsaturated uronic acid residues, the latter being comparable with their higher degree of depolymerisation. The analysis showed that ULMWHs are structurally related to LMWHs; however, their monosaccharide/oligosaccharide compositions and average molecular weights differed considerably explaining their different anticoagulant activities. The results relate structural features to activity, assisting the development of new and improved therapeutic agents, based on depolymerised heparin, for the prophylaxis and treatment of thrombotic disorders.

  4. Precision digital control systems

    NASA Astrophysics Data System (ADS)

    Vyskub, V. G.; Rozov, B. S.; Savelev, V. I.

    This book is concerned with the characteristics of digital control systems of great accuracy. A classification of such systems is considered along with aspects of stabilization, programmable control applications, digital tracking systems and servomechanisms, and precision systems for the control of a scanning laser beam. Other topics explored are related to systems of proportional control, linear devices and methods for increasing precision, approaches for further decreasing the response time in the case of high-speed operation, possibilities for the implementation of a logical control law, and methods for the study of precision digital control systems. A description is presented of precision automatic control systems which make use of electronic computers, taking into account the existing possibilities for an employment of computers in automatic control systems, approaches and studies required for including a computer in such control systems, and an analysis of the structure of automatic control systems with computers. Attention is also given to functional blocks in the considered systems.

  5. Precise Longitudinal Tracking of Microscopic Structures in Melanocytic Nevi Using Reflectance Confocal Microscopy: A Feasibility Study.

    PubMed

    Scope, Alon; Selinger, Limor; Oliviero, Margaret; Farnetani, Francesca; Moscarella, Elvira; Longo, Caterina; Rabinovitz, Harold S; Pellacani, Giovanni

    2016-03-01

    choice matching test, compared with a reference reader, 2 readers correctly matched baseline to follow-up tissue anchors in 40 of 43 nevi (93%; P < .01) and 42 of 43 nevi (98%; P < .01), respectively. In the annotation test, there was good agreement between 2 readers in all 29 cases (100%); the mean deviation was 2% (range, 0%-7.5%). Precise longitudinal tracking of microscopic structures in melanocytic nevi using RCM is feasible.

  6. Structural Analysis Made 'NESSUSary'

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Everywhere you look, chances are something that was designed and tested by a computer will be in plain view. Computers are now utilized to design and test just about everything imaginable, from automobiles and airplanes to bridges and boats, and elevators and escalators to streets and skyscrapers. Computer-design engineering first emerged in the 1970s, in the automobile and aerospace industries. Since computers were in their infancy, however, architects and engineers during the time were limited to producing only designs similar to hand-drafted drawings. (At the end of 1970s, a typical computer-aided design system was a 16-bit minicomputer with a price tag of $125,000.) Eventually, computers became more affordable and related software became more sophisticated, offering designers the "bells and whistles" to go beyond the limits of basic drafting and rendering, and venture into more skillful applications. One of the major advancements was the ability to test the objects being designed for the probability of failure. This advancement was especially important for the aerospace industry, where complicated and expensive structures are designed. The ability to perform reliability and risk assessment without using extensive hardware testing is critical to design and certification. In 1984, NASA initiated the Probabilistic Structural Analysis Methods (PSAM) project at Glenn Research Center to develop analysis methods and computer programs for the probabilistic structural analysis of select engine components for current Space Shuttle and future space propulsion systems. NASA envisioned that these methods and computational tools would play a critical role in establishing increased system performance and durability, and assist in structural system qualification and certification. Not only was the PSAM project beneficial to aerospace, it paved the way for a commercial risk- probability tool that is evaluating risks in diverse, down- to-Earth application

  7. The study about forming high-precision optical lens minimalized sinuous error structures for designed surface

    NASA Astrophysics Data System (ADS)

    Katahira, Yu; Fukuta, Masahiko; Katsuki, Masahide; Momochi, Takeshi; Yamamoto, Yoshihiro

    2016-09-01

    Recently, it has been required to improve qualities of aspherical lenses mounted on camera units. Optical lenses in highvolume production generally are applied with molding process using cemented carbide or Ni-P coated steel, which can be selected from lens material such as glass and plastic. Additionally it can be obtained high quality of the cut or ground surface on mold due to developments of different mold product technologies. As results, it can be less than 100nmPV as form-error and 1nmRa as surface roughness in molds. Furthermore it comes to need higher quality, not only formerror( PV) and surface roughness(Ra) but also other surface characteristics. For instance, it can be caused distorted shapes at imaging by middle spatial frequency undulations on the lens surface. In this study, we made focus on several types of sinuous structures, which can be classified into form errors for designed surface and deteriorate optical system performances. And it was obtained mold product processes minimalizing undulations on the surface. In the report, it was mentioned about the analyzing process by using PSD so as to evaluate micro undulations on the machined surface quantitatively. In addition, it was mentioned that the grinding process with circumferential velocity control was effective for large aperture lenses fabrication and could minimalize undulations appeared on outer area of the machined surface, and mentioned about the optical glass lens molding process by using the high precision press machine.

  8. Support trusses for large precision segmented reflectors - Preliminary design and analysis

    NASA Technical Reports Server (NTRS)

    Collins, Timothy J.; Fichter, W. B.

    1989-01-01

    The Precision Segmented Reflector (PSR) primary structures plan is outlined. Geometries and design considerations for erectable and deployable reflector support structures are discussed. Support truss requirements and goals for the PSR are given, and the results of static and dynamic analyses of a prototype four meter diameter structure are presented. In addition, similar results are presented for two 20-meter diameter support trusses. Implications of the analyses for the PSR program are considered and the formulation and limitations of current PSR finite element models are discussed. It is shown that if the secondary optical system is supported by a simple tripod design, the first six vibration modes are likely to be dominated by the secondary system. The 20-meter diameter support trusses are found to be quite stiff for structures of such large size.

  9. Maintaining high precision of isotope ratio analysis over extended periods of time.

    PubMed

    Brand, Willi A

    2009-06-01

    Stable isotope ratios are reliable and long lasting process tracers. In order to compare data from different locations or different sampling times at a high level of precision, a measurement strategy must include reliable traceability to an international stable isotope scale via a reference material (RM). Since these international RMs are available in low quantities only, we have developed our own analysis schemes involving laboratory working RM. In addition, quality assurance RMs are used to control the long-term performance of the delta-value assignments. The analysis schemes allow the construction of quality assurance performance charts over years of operation. In this contribution, the performance of three typical techniques established in IsoLab at the MPI-BGC in Jena is discussed. The techniques are (1) isotope ratio mass spectrometry with an elemental analyser for delta(15)N and delta(13)C analysis of bulk (organic) material, (2) high precision delta(13)C and delta(18)O analysis of CO(2) in clean-air samples, and (3) stable isotope analysis of water samples using a high-temperature reaction with carbon. In addition, reference strategies on a laser ablation system for high spatial resolution delta(13)C analysis in tree rings is exemplified briefly.

  10. High precision calcium isotope analysis using 42Ca-48Ca double-spike TIMS technique

    NASA Astrophysics Data System (ADS)

    Feng, L.; Zhou, L.; Gao, S.; Tong, S. Y.; Zhou, M. L.

    2014-12-01

    Double spike techniques are widely used for determining calcium isotopic compositions of natural samples. The most important factor controlling precision of the double spike technique is the choice of appropriate spike isotope pair, the composition of double spikes and the ratio of spike to sample(CSp/CN). We propose an optimal 42Ca-48Ca double spike protocol which yields the best internal precision for calcium isotopic composition determinations among all kinds of spike pairs and various spike compositions and ratios of spike to sample, as predicted by linear error propagation method. It is suggested to use spike composition of 42Ca/(42Ca+48Ca) = 0.44 mol/mol and CSp/(CN+ CSp)= 0.12mol/mol because it takes both advantages of the largest mass dispersion between 42Ca and 48Ca (14%) and lowest spike cost. Spiked samples were purified by pass through homemade micro-column filled with Ca special resin. K, Ti and other interference elements were completely separated, while 100% calcium was recovered with negligible blank. Data collection includes integration time, idle time, focus and peakcenter frequency, which were all carefully designed for the highest internal precision and lowest analysis time. All beams were automatically measured in a sequence by Triton TIMS so as to eliminate difference of analytical conditions between samples and standards, and also to increase the analytical throughputs. The typical internal precision of 100 duty cycles for one beam is 0.012‒0.015 ‰ (2δSEM), which agrees well with the predicted internal precision of 0.0124 ‰ (2δSEM). Our methods improve internal precisions by a factor of 2‒10 compared to previous methods of determination of calcium isotopic compositions by double spike TIMS. We analyzed NIST SRM 915a, NIST SRM 915b and Pacific Seawater as well as interspersed geological samples during two months. The obtained average δ44/40Ca (all relative to NIST SRM 915a) is 0.02 ± 0.02 ‰ (n=28), 0.72±0.04 ‰ (n=10) and 1

  11. Design and validation of high-precision wireless strain sensors for structural health monitoring of steel structures

    NASA Astrophysics Data System (ADS)

    Jo, Hongki; Park, JongWoong; Spencer, B. F., Jr.; Jung, Hyung-Jo

    2012-04-01

    Due to their cost-effectiveness and ease of installation, smart wireless sensors have received considerable recent attention for structural health monitoring of civil infrastructure. Though various wireless smart sensor networks (WSSN) have been successfully implemented for full-scale structural health monitoring (SHM) applications, monitoring of low-level ambient strain still remains a challenging problem for wireless smart sensors (WSS) due to A/D converter resolution, inherent circuit noise, and the need for automatic operation. In this paper, the design and validation of high-precision strain sensor board for Imote2 WSS platform and its application to SHM of a cable-stayed bridge are presented. By accurate and automated balancing the Wheatstone bridge, signal amplification of up to 2507-times can be obtained. Temperature compensation and shunt calibration are implemented. In addition to traditional foil-type strain gages, the sensor board has been designed to accommodate a friction-type magnet strain sensor, facilitating fast and easy deployment. The sensor board has been calibrated using lab-scale tests, and then deployed on a full-scale cable-stayed bridge to verify its performance.

  12. High-precision measurement of tidal current structures using coastal acoustic tomography

    NASA Astrophysics Data System (ADS)

    Zhang, Chuanzheng; Zhu, Xiao-Hua; Zhu, Ze-Nan; Liu, Wenhu; Zhang, Zhongzhe; Fan, Xiaopeng; Zhao, Ruixiang; Dong, Menghong; Wang, Min

    2017-07-01

    A high-precision coastal acoustic tomography (CAT) experiment for reconstructing the current variation in Dalian Bay (DLB) was successfully conducted by 11 coastal acoustic tomography systems during March 7-8, 2015. The horizontal distributions of tidal currents and residual currents were mapped well by the inverse method, which used reciprocal travel time data along 51 successful sound transmission rays. The semi-diurnal tide is dominant in DLB, with a maximum speed of 0.69 m s-1 at the eastern and southwestern parts near the bay mouth that gradually decreases toward the inner bay with an average velocity of 0.31 m s-1. The residual current enters the observational domain from the two flanks of the bay mouth and flows out in the inner bay. One anticyclone and one cyclone were noted inside DLB as was one cyclone at the bay mouth. The maximum residual current in the observational domain reached 0.11 m s-1, with a mean residual current of 0.03 m s-1. The upper 15-m depth-averaged inverse velocities were in excellent agreement with the moored Acoustic Doppler Current Profiler (ADCP) at the center of the bay, with a root-mean-square difference (RMSD) of 0.04 m s-1 for the eastward and northward components. The precision of the present tomography measurements was the highest thus far owing to the largest number of transmission rays ever recorded. Sensitivity experiments showed that the RMSD between CAT and moored-ADCP increased from 0.04 m s-1 to 0.08 m s-1 for both the eastward and northward velocities when reducing the number of transmission rays from 51 to 11. The observational accuracy was determined by the spatial resolution of acoustic ray in the CAT measurements. The cost-optimal scheme consisted of 29 transmission rays with a spatial resolution of acoustic ray of 2.03 √{ km2 / ray numbers } . Moreover, a dynamic analysis of the residual currents showed that the horizontal pressure gradient of residual sea level and Coriolis force contribute 38.3% and 36

  13. Spatial bandwidth analysis of fast backward Fresnel diffraction for precise computer-generated hologram design.

    PubMed

    Liang, Jinyang; Becker, Michael F

    2014-09-20

    Designing near-field computer-generated holograms (CGHs) for a spatial light modulator (SLM) requires backward diffraction calculations. However, direct implementation of the discrete computational model of the Fresnel diffraction integral often produces inaccurate reconstruction. Finite sizes of the SLM and the target image, as well as aliasing, are major sources of error. Here we present a new design prescription for precise near-field CGHs based on comprehensive analysis of the spatial bandwidth. We demonstrate that, by controlling two free variables related to the target image, the designed hologram is free from aliasing and can have minimum error. To achieve this, we analyze the geometry of the target image, hologram, and Fourier transform plane of the target image to derive conditions for minimizing reconstruction error due to truncation of spatial frequencies lying outside of the hologram. The design prescription is verified by examples showing reconstruction error versus controlled parameters. Finally, it is applied to precise three-dimensional image reconstruction.

  14. Precision measurement system and analysis of low core signal loss in DCF couplers

    NASA Astrophysics Data System (ADS)

    Yan, P.; Wang, X. J.; Fu, Ch; Li, D.; Sun, J. Y.; Gong, M. L.; Xiao, Q. R.

    2016-07-01

    In order to achieve higher output power of double cladding fiber lasers, low signal loss has become a focus in researches on optical technology, especially double-clad fiber (DCF) couplers. According to the analysis, DCF couplers with low core signal loss (less than 1%) are produced. To obtain higher precision, we use the first-proposed method for core signal transfer efficiency measurement based on the fiber propagation field image processing. To the best of our knowledge, we report, for the first time, the results of the core signal loss less than 1% in DCF coupler measured by our measurement with high stability and relative precision. The measurement values can assess the quality of DCF couplers and be used as a signal to suggest the improvement on the processing technology of our self-made DCF couplers.

  15. Structural Analysis of Biodiversity

    PubMed Central

    Sirovich, Lawrence; Stoeckle, Mark Y.; Zhang, Yu

    2010-01-01

    Large, recently-available genomic databases cover a wide range of life forms, suggesting opportunity for insights into genetic structure of biodiversity. In this study we refine our recently-described technique using indicator vectors to analyze and visualize nucleotide sequences. The indicator vector approach generates correlation matrices, dubbed Klee diagrams, which represent a novel way of assembling and viewing large genomic datasets. To explore its potential utility, here we apply the improved algorithm to a collection of almost 17000 DNA barcode sequences covering 12 widely-separated animal taxa, demonstrating that indicator vectors for classification gave correct assignment in all 11000 test cases. Indicator vector analysis revealed discontinuities corresponding to species- and higher-level taxonomic divisions, suggesting an efficient approach to classification of organisms from poorly-studied groups. As compared to standard distance metrics, indicator vectors preserve diagnostic character probabilities, enable automated classification of test sequences, and generate high-information density single-page displays. These results support application of indicator vectors for comparative analysis of large nucleotide data sets and raise prospect of gaining insight into broad-scale patterns in the genetic structure of biodiversity. PMID:20195371

  16. Structural analysis of biodiversity.

    PubMed

    Sirovich, Lawrence; Stoeckle, Mark Y; Zhang, Yu

    2010-02-24

    Large, recently-available genomic databases cover a wide range of life forms, suggesting opportunity for insights into genetic structure of biodiversity. In this study we refine our recently-described technique using indicator vectors to analyze and visualize nucleotide sequences. The indicator vector approach generates correlation matrices, dubbed Klee diagrams, which represent a novel way of assembling and viewing large genomic datasets. To explore its potential utility, here we apply the improved algorithm to a collection of almost 17,000 DNA barcode sequences covering 12 widely-separated animal taxa, demonstrating that indicator vectors for classification gave correct assignment in all 11,000 test cases. Indicator vector analysis revealed discontinuities corresponding to species- and higher-level taxonomic divisions, suggesting an efficient approach to classification of organisms from poorly-studied groups. As compared to standard distance metrics, indicator vectors preserve diagnostic character probabilities, enable automated classification of test sequences, and generate high-information density single-page displays. These results support application of indicator vectors for comparative analysis of large nucleotide data sets and raise prospect of gaining insight into broad-scale patterns in the genetic structure of biodiversity.

  17. Outlier analysis of functional genomic profiles enriches for oncology targets and enables precision medicine.

    PubMed

    Zhu, Zhou; Ihle, Nathan T; Rejto, Paul A; Zarrinkar, Patrick P

    2016-06-13

    Genome-scale functional genomic screens across large cell line panels provide a rich resource for discovering tumor vulnerabilities that can lead to the next generation of targeted therapies. Their data analysis typically has focused on identifying genes whose knockdown enhances response in various pre-defined genetic contexts, which are limited by biological complexities as well as the incompleteness of our knowledge. We thus introduce a complementary data mining strategy to identify genes with exceptional sensitivity in subsets, or outlier groups, of cell lines, allowing an unbiased analysis without any a priori assumption about the underlying biology of dependency. Genes with outlier features are strongly and specifically enriched with those known to be associated with cancer and relevant biological processes, despite no a priori knowledge being used to drive the analysis. Identification of exceptional responders (outliers) may not lead only to new candidates for therapeutic intervention, but also tumor indications and response biomarkers for companion precision medicine strategies. Several tumor suppressors have an outlier sensitivity pattern, supporting and generalizing the notion that tumor suppressors can play context-dependent oncogenic roles. The novel application of outlier analysis described here demonstrates a systematic and data-driven analytical strategy to decipher large-scale functional genomic data for oncology target and precision medicine discoveries.

  18. Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region

    SciTech Connect

    Xiaochao Zheng; Konrad Aniol; David Armstrong; Todd Averett; William Bertozzi; Sebastien Binet; Etienne Burtin; Emmanuel Busato; Cornel Butuceanu; John Calarco; Alexandre Camsonne; Gordon Cates; Zhengwei Chai; Jian-ping Chen; Seonho Choi; Eugene Chudakov; Francesco Cusanno; Raffaele De Leo; Alexandre Deur; Sonja Dieterich; Dipangkar Dutta; John Finn; Salvatore Frullani; Haiyan Gao; Juncai Gao; Franco Garibaldi; Shalev Gilad; Ronald Gilman; Javier Gomez; Jens-ole Hansen; Douglas Higinbotham; Wendy Hinton; Tanja Horn; Cornelis De Jager; Xiaodong Jiang; Lisa Kaufman; James Kelly; Wolfgang Korsch; Kevin Kramer; John Lerose; David Lhuillier; Nilanga Liyanage; Demetrius Margaziotis; Frederic Marie; Pete Markowitz; Kathy Mccormick; Zein-eddine Meziani; Robert Michaels; Bryan Moffit; Sirish Nanda; Damien Neyret; Sarah Phillips; Anthony Powell; Thierry Pussieux; Bodo Reitz; Julie Roche; Michael Roedelbronn; Guy Ron; Marat Rvachev; Arunava Saha; Nikolai Savvinov; Jaideep Singh; Simon Sirca; Karl Slifer; Patricia Solvignon; Paul Souder; Daniel Steiner; Steffen Strauch; Vincent Sulkosky; William Tobias; Guido Urciuoli; Antonin Vacheret; Bogdan Wojtsekhowski; Hong Xiang; Yuan Xiao; Feng Xiong; Bin Zhang; Lingyan Zhu; Xiaofeng Zhu; Piotr Zolnierczuk

    2004-05-01

    We report on measurements of the neutron spin asymmetries A{sub 1,2}{sup n} and polarized structure functions g{sub 1,2}{sup n} at three kinematics in the deep inelastic region, with x = 0.33, 0.47 and .60 and Q{sub 2} = 2.7, 3.5 and 4.8 (GeV/c){sup 2}, respectively. These measurements were performed using a 5.7 GeV longitudinally-polarized electron beam and a polarized {sup 3}He target. The results for A{sub 1}{sup n} and g{sub 1}{sup n} at x = 0.33 are consistent with previous world data and, at the two higher x points, have improved the precision of the world data by about an order of magnitude. The new A{sub 1}{sup n} data show a zero crossing around x = 0.47 and the value at x = 0.60 is significantly positive. These results agree with a next-to-leading order QCD analysis of previous world data. The trend of data at high x agrees with constituent quark model predictions but disagrees with that from leading-order perturbative QCD (pQCD) assuming hadron helicity conservation. Results for A{sub 2}{sup n} and g{sub 2}{sup n} have a precision comparable to the best world data in this kinematic region. Combined with previous world data, the moment d{sub 2}{sup n} was evaluated and the new result has improved the precision of this quantity by about a factor of two. When combined with the world proton data, polarized quark distribution functions were extracted from the new g{sub 1}{sup n}/F{sub 1}{sup n} values based on the quark parton model. While results for {Delta}u/u agree well with predictions from various models, results for {Delta}d/d disagree with the leading-order pQCD prediction when hadron helicity conservation is imposed.

  19. Deriving PWV from BDS Observations with PPP approach and Precision Analysis in China Region

    NASA Astrophysics Data System (ADS)

    Li, Min

    2014-05-01

    The precipitable water vapour (PWV) is the key parameter of the weather analysis and numerical weather prediction. And it is now widely adopted to derive PWV with the zenithtropospheric delay (ZTD) estimated from GNSS observations. The BeiDou System (BDS) now has 14 satellites in service and provides a good coverage over the China region with its GEO and IGSO constellations. In this contribution, we concentrate on PWV inversion using only BDS observations and its precision evaluation with the PANDA software developed at Wuhan University. The BDS/GPS dual-frequency dual-mode data from June 1 to September 1 2013 are collected at 8 stations in the China region. By the PPP approach, the ZTDs are estimated every 2-hour at each station using a piecewise constant model with BDS precise orbit and clock products, which are generated from the BETS(BeiDou Experiment Tracking Stations) network with 14 stations distributed globally. Then the PWVs are obtained by the conversion factor and zenith wet delays (ZWDs) retrieved from the estimated ZTDs. Firstly the PPP-inferred BDS-PWV is compared to that provided by the AERONET. And then the 3-month GPS-PWV at these 8 stations isalso estimatedin the same way, and used as reference values for BDS-PWV comparison.Their precision differences are further discussed.

  20. Evaluation of precision and accuracy of selenium measurements in biological materials using neutron activation analysis

    SciTech Connect

    Greenberg, R.R.

    1988-01-01

    In recent years, the accurate determination of selenium in biological materials has become increasingly important in view of the essential nature of this element for human nutrition and its possible role as a protective agent against cancer. Unfortunately, the accurate determination of selenium in biological materials is often difficult for most analytical techniques for a variety of reasons, including interferences, complicated selenium chemistry due to the presence of this element in multiple oxidation states and in a variety of different organic species, stability and resistance to destruction of some of these organo-selenium species during acid dissolution, volatility of some selenium compounds, and potential for contamination. Neutron activation analysis (NAA) can be one of the best analytical techniques for selenium determinations in biological materials for a number of reasons. Currently, precision at the 1% level (1s) and overall accuracy at the 1 to 2% level (95% confidence interval) can be attained at the U.S. National Bureau of Standards (NBS) for selenium determinations in biological materials when counting statistics are not limiting (using the {sup 75}Se isotope). An example of this level of precision and accuracy is summarized. Achieving this level of accuracy, however, requires strict attention to all sources of systematic error. Precise and accurate results can also be obtained after radiochemical separations.

  1. Confirmation of a de novo structure prediction for an atomically precise monolayer-coated silver nanoparticle

    PubMed Central

    Conn, Brian E.; Atnagulov, Aydar; Yoon, Bokwon; Barnett, Robert N.; Landman, Uzi; Bigioni, Terry P.

    2016-01-01

    Fathoming the principles underpinning the structures of monolayer-coated molecular metal nanoparticles remains an enduring challenge. Notwithstanding recent x-ray determinations, coveted veritable de novo structural predictions are scarce. Building on recent syntheses and de novo structure predictions of M3AuxAg17−x(TBBT)12, where M is a countercation, x = 0 or 1, and TBBT is 4-tert-butylbenzenethiol, we report an x-ray–determined structure that authenticates an a priori prediction and, in conjunction with first-principles theoretical analysis, lends force to the underlying forecasting methodology. The predicted and verified Ag(SR)3 monomer, together with the recently discovered Ag2(SR)5 dimer and Ag3(SR)6 trimer, establishes a family of unique mount motifs for silver thiolate nanoparticles, expanding knowledge beyond the earlier-known Au-S staples in thiol-capped gold nanoclusters. These findings demonstrate key principles underlying ligand-shell anchoring to the metal core, as well as unique T-like benzene dimer and cyclic benzene trimer ligand bundling configurations, opening vistas for rational design of metal and alloy nanoparticles. PMID:28138537

  2. Fully automatic and precise data analysis developed for time-of-flight mass spectrometry.

    PubMed

    Meyer, Stefan; Riedo, Andreas; Neuland, Maike B; Tulej, Marek; Wurz, Peter

    2017-09-01

    Scientific objectives of current and future space missions are focused on the investigation of the origin and evolution of the solar system with the particular emphasis on habitability and signatures of past and present life. For in situ measurements of the chemical composition of solid samples on planetary surfaces, the neutral atmospheric gas and the thermal plasma of planetary atmospheres, the application of mass spectrometers making use of time-of-flight mass analysers is a technique widely used. However, such investigations imply measurements with good statistics and, thus, a large amount of data to be analysed. Therefore, faster and especially robust automated data analysis with enhanced accuracy is required. In this contribution, an automatic data analysis software, which allows fast and precise quantitative data analysis of time-of-flight mass spectrometric data, is presented and discussed in detail. A crucial part of this software is a robust and fast peak finding algorithm with a consecutive numerical integration method allowing precise data analysis. We tested our analysis software with data from different time-of-flight mass spectrometers and different measurement campaigns thereof. The quantitative analysis of isotopes, using automatic data analysis, yields results with an accuracy of isotope ratios up to 100 ppm for a signal-to-noise ratio (SNR) of 10(4) . We show that the accuracy of isotope ratios is in fact proportional to SNR(-1) . Furthermore, we observe that the accuracy of isotope ratios is inversely proportional to the mass resolution. Additionally, we show that the accuracy of isotope ratios is depending on the sample width Ts by Ts(0.5) . Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  3. voom: precision weights unlock linear model analysis tools for RNA-seq read counts

    PubMed Central

    2014-01-01

    New normal linear modeling strategies are presented for analyzing read counts from RNA-seq experiments. The voom method estimates the mean-variance relationship of the log-counts, generates a precision weight for each observation and enters these into the limma empirical Bayes analysis pipeline. This opens access for RNA-seq analysts to a large body of methodology developed for microarrays. Simulation studies show that voom performs as well or better than count-based RNA-seq methods even when the data are generated according to the assumptions of the earlier methods. Two case studies illustrate the use of linear modeling and gene set testing methods. PMID:24485249

  4. Numerical analysis of fluid flow in the throttle poppet valve channel in precision machinery

    NASA Astrophysics Data System (ADS)

    Xu, Tongle; Zhang, Xinyi

    2008-12-01

    The velocity, pressure, stream function and velocity magnitude in different case are discussed by numerical analysis and simulation of the fluid flow in the throttle poppet valve channel in Precision Machinery. The place and intensity of vortexes are analyzed and the main causations of energy loss are found. It is indicated that the stream function, velocity magnitude, energy loss and flow noise is reduced, negative pressure is changed and the use of energy is improved by optimizing design of the throttle poppet valve spool.

  5. Theoretical study of precision and accuracy of strain analysis by nano-beam electron diffraction.

    PubMed

    Mahr, Christoph; Müller-Caspary, Knut; Grieb, Tim; Schowalter, Marco; Mehrtens, Thorsten; Krause, Florian F; Zillmann, Dennis; Rosenauer, Andreas

    2015-11-01

    Measurement of lattice strain is important to characterize semiconductor nanostructures. As strain has large influence on the electronic band structure, methods for the measurement of strain with high precision, accuracy and spatial resolution in a large field of view are mandatory. In this paper we present a theoretical study of precision and accuracy of measurement of strain by convergent nano-beam electron diffraction. It is found that the accuracy of the evaluation suffers from halos in the diffraction pattern caused by a variation of strain within the area covered by the focussed electron beam. This effect, which is expected to be strong at sharp interfaces between materials with different lattice plane distances, will be discussed for convergent-beam electron diffraction patterns using a conventional probe and for patterns formed by a precessing electron beam. Furthermore, we discuss approaches to optimize the accuracy of strain measured at interfaces. The study is based on the evaluation of diffraction patterns simulated for different realistic structures that have been investigated experimentally in former publications. These simulations account for thermal diffuse scattering using the frozen-lattice approach and the modulation-transfer function of the image-recording system. The influence of Poisson noise is also investigated.

  6. Precision structural engineering of self-rolled-up 3D nanomembranes guided by transient quasi-static FEM modeling.

    PubMed

    Huang, Wen; Koric, Seid; Yu, Xin; Hsia, K Jimmy; Li, Xiuling

    2014-11-12

    Micro- and nanoscale tubular structures can be formed by strain-induced self-rolled-up nanomembranes. Precision engineering of the shape and dimension determines the performance of devices based on this platform for electronic, optical, and biological applications. A transient quasi-static finite element method (FEM) with moving boundary conditions is proposed as a general approach to design diverse types of three-dimensional (3D) rolled-up geometries. This method captures the dynamic release process of membranes through etching driven by mismatch strain and accurately predicts the final dimensions of rolled-up structures. Guided by the FEM modeling, experimental demonstration using silicon nitride membranes was achieved with unprecedented precision including controlling fractional turns of a rolled-up membrane, anisotropic rolling to form helical structures, and local stress control for 3D hierarchical architectures.

  7. High precision 11B/10B analysis with a simplified MC-ICP-MS

    NASA Astrophysics Data System (ADS)

    Tanimizu, M.; Nagaishi, K.

    2012-04-01

    Boron isotope ratio is a powerful tracer in the fields of geochemistry, biochemistry, and environmental chemistry. One important application of 11B/10B isotope ratio in geochemistry is as an indicator for paleo pH of seawater recorded in marine carbonates in deep-sea sediments. Boron isotope ratios are determined by TIMS or MC-ICP-MS with precisions of better than 0.1 % RSD, but a large inter-lab discrepancy of 0.6 % is still observed for actual carbonate samples (Foster, 2008). Here, we tried to determine B isotope ratio by MC-ICP-MS with a simple and common analytical techniques using a quartz sample introduction system with a PFA nebulizer, and compared to recently developed precise B isotope ratio analysis techniques by TIMS in positive ion detection mode determined as Cs2BO2+ ions with sample amount of <100 ng (Ishikawa and Nagaishi, 2011) and by MC-ICP-MS (Foster, 2008, Louvat et al., 2011). 11B/10B isotope ratios of a 50 ppb B solution dissolved in a HNO3, mannitol, HF-mixed solution were determined against an isotopic reference NIST-SRM 951 with a standard sample bracketing technique in the wet plasma condition. Resultant analytical reproducibility (twice standard deviation) was +/-0.02 % with a consumption of 50 ng B, and the washout time was comparable to that of NH3 gas addition to the introduction system (Foster, 2008). 11B/10B isotope ratios of actual carbonate sample and seawater were determined after simple chemical purification with a common cation exchange resin instead of a boron selective resin. Their relative differences from the standard were consistent with those determined by the positive TIMS within analytical uncertainty. Current potential of MC-ICP-MS for precise B isotopic analysis will be discussed. Foster, G., 2008. Seawater pH, pCO2 and [CO32-] variations in the Caribbean Sea over the last 130kyr: A boron isotope and B/Ca study of planktic foraminifera, Earth Planet. Sci. Lett., 271, 254-266. Ishikawa, T. and Nagaishi, K., 2011. High-precision

  8. Estimating sparse precision matrices

    NASA Astrophysics Data System (ADS)

    Padmanabhan, Nikhil; White, Martin; Zhou, Harrison H.; O'Connell, Ross

    2016-08-01

    We apply a method recently introduced to the statistical literature to directly estimate the precision matrix from an ensemble of samples drawn from a corresponding Gaussian distribution. Motivated by the observation that cosmological precision matrices are often approximately sparse, the method allows one to exploit this sparsity of the precision matrix to more quickly converge to an asymptotic 1/sqrt{N_sim} rate while simultaneously providing an error model for all of the terms. Such an estimate can be used as the starting point for further regularization efforts which can improve upon the 1/sqrt{N_sim} limit above, and incorporating such additional steps is straightforward within this framework. We demonstrate the technique with toy models and with an example motivated by large-scale structure two-point analysis, showing significant improvements in the rate of convergence. For the large-scale structure example, we find errors on the precision matrix which are factors of 5 smaller than for the sample precision matrix for thousands of simulations or, alternatively, convergence to the same error level with more than an order of magnitude fewer simulations.

  9. Guarding the Gate: Remote Structured Assessments to Enhance Enrollment Precision in Depression Trials.

    PubMed

    Freeman, Marlene P; Pooley, James; Flynn, Martina J; Baer, Lee; Mischoulon, David; Mou, David; Fava, Maurizio

    2017-04-01

    Failed treatment trials are common in major depressive disorder and treatment-resistant depression, and remotely performed multifaceted, centralized structured interviews can potentially enhance signal detection by ensuring that enrolled patients meet eligibility criteria. We assessed the use of a specific remote structured interview that validated the diagnosis, level of treatment resistance, and depression severity. The objectives were to (1) assess the rate at which patients who were deemed eligible for participation in trials by site investigators were ineligible, (2) assess the reasons for ineligibility, (3) compare rates of ineligibility between academic and nonacademic sites, (4) compare eligibility between US and non-US sites, and (5) report the placebo response rates in trials utilizing this quality assurance approach, comparing its placebo response rates with those reported in the literature. Methods included a pooled analysis of 9 studies that utilized this methodology (SAFER interviews). Overall, 15.33% of patients who had been deemed eligible at research sites were not eligible after the structured interviews. The most common reason was that patients did not meet the study requirements for level of treatment resistance. Pass rates were significantly higher at non-US compared with US sites (94.6% vs 83.3%, respectively; P < 0.001). There was not a significant difference between academic and nonacademic sites (87.8% vs 82.4%; P = 0.08). Placebo response rates were 13.0% to 27.3%, below the 30% to 40% average in antidepressant clinical trials, suggesting a benefit of the quality assurance provided by these interviews. The use of a remotely structured interview by experienced clinical researchers was feasible and possibly contributed to lower-than-average placebo response rates. The difference between US and non-US sites should be the subject of further research.

  10. An Analysis of the Impact of AN Improved Gnss Constellation on Precise Point Positioning

    NASA Astrophysics Data System (ADS)

    Garcia, Carlos; Leandro, Rodrigo; Santos, Marcelo; Langley, Richard

    During the past few years there have been an increasing number of GNSS research studies on the predicted impact on positioning due to the implementation and use of Galileo and GLONASS alongside GPS. It is expected that some years from now these other two satellite constellations will be complete and therefore there would be around about three times more GNSS satellites in the sky compared to those provided by GPS alone, which would bring a considerable improvement in terms of satellite geometry at any location on the globe. Most of the research studies on the simultaneous use GPS and Galileo measurements, for example, have been carried out through signal simulation, by means of either software or hardware simulators. In order to analyze the impact of the larger number of available satellites, but using actual satellite signals, we have used a different technique in which the current GPS constellation is virtually doubled. This means that we are simulating a second GNSS system with the same orbital characteristics as GPS (but not considering any improved signal characteristics it may have) in different geometry condition - in effect, a doubling of the GPS constellation. The exact procedure is explained in this paper. The main advantages of this technique are that it does not require the use of a simulator; it is based on real satellite signals; and it is reasonably simple to perform if the appropriate positioning engine is available. Using this technique, we are able to analyze the possible impact of a second GNSS constellation. Although it is not possible to derive immutable numbers to quantify this improvement (a shared limitation of any other simulation analysis), due to the nature of the analysis technique, it is possible to have a reasonably clear idea of what the positioning performance will actually look like. Precise point positioning (PPP) is one of the existing techniques for determining point coordinates using a GPS receiver. In this technique

  11. Performance of BDS-3: Measurement Quality Analysis, Precise Orbit and Clock Determination.

    PubMed

    Xie, Xin; Geng, Tao; Zhao, Qile; Liu, Jingnan; Wang, Bin

    2017-05-28

    Since 2015, China has successfully launched five experimental BeiDou global navigation system (BDS-3) satellites for expanding the regional system to global coverage. An initial performance assessment and characterization analysis of the BDS-3 is presented. Twenty days of tracking data have been collected from eleven monitoring stations. The tracking characteristics and measurement quality are analyzed and compared with the regional BDS (BDS-2) in terms of observed carrier-to-noise density ratio, pseudo-range multipath, and noise. The preliminary results suggest that the measurement quality of BDS-3 outperforms the BDS-2 for the same type of satellites. In addition, the analysis of multipath combinations reveals that the problem of satellite-induced code biases found in BDS-2 seems to have been solved for BDS-3. Precise orbit and clock determination are carried out and evaluated. The orbit overlap comparison show a precision of 2-6 dm in 3D root mean square (RMS) and 6-14 cm in the radial component for experimental BDS-3 satellites. External validations with satellite laser ranging (SLR) show residual RMS on the level of 1-3 dm. Finally, the performance of the new-generation onboard atomic clocks is evaluated and results confirm an increased stability compared to BDS-2 satellite clocks.

  12. A novel algorithm for a precise analysis of subchondral bone alterations

    PubMed Central

    Gao, Liang; Orth, Patrick; Goebel, Lars K. H.; Cucchiarini, Magali; Madry, Henning

    2016-01-01

    Subchondral bone alterations are emerging as considerable clinical problems associated with articular cartilage repair. Their analysis exposes a pattern of variable changes, including intra-lesional osteophytes, residual microfracture holes, peri-hole bone resorption, and subchondral bone cysts. A precise distinction between them is becoming increasingly important. Here, we present a tailored algorithm based on continuous data to analyse subchondral bone changes using micro-CT images, allowing for a clear definition of each entity. We evaluated this algorithm using data sets originating from two large animal models of osteochondral repair. Intra-lesional osteophytes were detected in 3 of 10 defects in the minipig and in 4 of 5 defects in the sheep model. Peri-hole bone resorption was found in 22 of 30 microfracture holes in the minipig and in 17 of 30 microfracture holes in the sheep model. Subchondral bone cysts appeared in 1 microfracture hole in the minipig and in 5 microfracture holes in the sheep model (n = 30 holes each). Calculation of inter-rater agreement (90% agreement) and Cohen’s kappa (kappa = 0.874) revealed that the novel algorithm is highly reliable, reproducible, and valid. Comparison analysis with the best existing semi-quantitative evaluation method was also performed, supporting the enhanced precision of this algorithm. PMID:27596562

  13. Performance of BDS-3: Measurement Quality Analysis, Precise Orbit and Clock Determination

    PubMed Central

    Xie, Xin; Geng, Tao; Zhao, Qile; Liu, Jingnan; Wang, Bin

    2017-01-01

    Since 2015, China has successfully launched five experimental BeiDou global navigation system (BDS-3) satellites for expanding the regional system to global coverage. An initial performance assessment and characterization analysis of the BDS-3 is presented. Twenty days of tracking data have been collected from eleven monitoring stations. The tracking characteristics and measurement quality are analyzed and compared with the regional BDS (BDS-2) in terms of observed carrier-to-noise density ratio, pseudo-range multipath, and noise. The preliminary results suggest that the measurement quality of BDS-3 outperforms the BDS-2 for the same type of satellites. In addition, the analysis of multipath combinations reveals that the problem of satellite-induced code biases found in BDS-2 seems to have been solved for BDS-3. Precise orbit and clock determination are carried out and evaluated. The orbit overlap comparison show a precision of 2–6 dm in 3D root mean square (RMS) and 6–14 cm in the radial component for experimental BDS-3 satellites. External validations with satellite laser ranging (SLR) show residual RMS on the level of 1–3 dm. Finally, the performance of the new-generation onboard atomic clocks is evaluated and results confirm an increased stability compared to BDS-2 satellite clocks. PMID:28555027

  14. Development of millimeter-wave accelerating structures using precision metal forming technology

    SciTech Connect

    2003-06-03

    High gradients in radio-frequency (RF) driven accelerators require short wavelengths that have the concomitant requirements of small feature size and high tolerances, 1-2 {micro}m for millimeter wavelengths. Precision metal-forming stampling has the promise of meeting those tolerances with high production rates. This STI will evaluate that promise.

  15. Oxygen isotope analysis of phosphate: improved precision using TC/EA CF-IRMS.

    PubMed

    LaPorte, D F; Holmden, C; Patterson, W P; Prokopiuk, T; Eglington, B M

    2009-06-01

    Oxygen isotope values of biogenic apatite have long demonstrated considerable promise for paleothermometry potential because of the abundance of material in the fossil record and greater resistance of apatite to diagenesis compared to carbonate. Unfortunately, this promise has not been fully realized because of relatively poor precision of isotopic measurements, and exceedingly small size of some substrates for analysis. Building on previous work, we demonstrate that it is possible to improve precision of delta18O(PO4) measurements using a 'reverse-plumbed' thermal conversion elemental analyzer (TC/EA) coupled to a continuous flow isotope ratio mass spectrometer (CF-IRMS) via a helium stream [Correction made here after initial online publication]. This modification to the flow of helium through the TC/EA, and careful location of the packing of glassy carbon fragments relative to the hot spot in the reactor, leads to narrower, more symmetrically distributed CO elution peaks with diminished tailing. In addition, we describe our apatite purification chemistry that uses nitric acid and cation exchange resin. Purification chemistry is optimized for processing small samples, minimizing isotopic fractionation of PO4(-3) and permitting Ca, Sr and Nd to be eluted and purified further for the measurement of delta44Ca and 87Sr/86Sr in modern biogenic apatite and 143Nd/144Nd in fossil apatite. Our methodology yields an external precision of +/- 0.15 per thousand (1sigma) for delta18O(PO4). The uncertainty is related to the preparation of the Ag3PO4 salt, conversion to CO gas in a reversed-plumbed TC/EA, analysis of oxygen isotopes using a CF-IRMS, and uncertainty in constructing calibration lines that convert raw delta18O data to the VSMOW scale. Matrix matching of samples and standards for the purpose of calibration to the VSMOW scale was determined to be unnecessary. Our method requires only slightly modified equipment that is widely available. This fact, and the

  16. Statistical analysis for improving data precision in the SPME GC-MS analysis of blackberry (Rubus ulmifolius Schott) volatiles.

    PubMed

    D'Agostino, M F; Sanz, J; Martínez-Castro, I; Giuffrè, A M; Sicari, V; Soria, A C

    2014-07-01

    Statistical analysis has been used for the first time to evaluate the dispersion of quantitative data in the solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis of blackberry (Rubus ulmifolius Schott) volatiles with the aim of improving their precision. Experimental and randomly simulated data were compared using different statistical parameters (correlation coefficients, Principal Component Analysis loadings and eigenvalues). Non-random factors were shown to significantly contribute to total dispersion; groups of volatile compounds could be associated with these factors. A significant improvement of precision was achieved when considering percent concentration ratios, rather than percent values, among those blackberry volatiles with a similar dispersion behavior. As novelty over previous references, and to complement this main objective, the presence of non-random dispersion trends in data from simple blackberry model systems was evidenced. Although the influence of the type of matrix on data precision was proved, the possibility of a better understanding of the dispersion patterns in real samples was not possible from model systems. The approach here used was validated for the first time through the multicomponent characterization of Italian blackberries from different harvest years.

  17. Determination of precise pyrimidine cationic structure by vacuum ultraviolet mass-analyzed threshold ionization spectroscopy.

    PubMed

    Kim, Jae Han; Lee, Ji Hye; Hwang, Hyonseok; Kim, Hong Lae; Kwon, Chan Ho

    2014-01-28

    The vibrational spectrum of a pyrimidine cation in the ground electronic state was obtained using vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy. Accurate ionization energy of pyrimidine was determined from the 0-0 band position in the VUV-MATI spectrum and was measured by varying the PFI field to the zero field limit, which is 75,258 ± 7 cm(-1) (9.3308 eV). The spectrum displayed a large number of vibrational peaks, which could be nearly completely assigned through Franck-Condon analysis performed with variations of geometrical parameters at the B3LYP/cc-pVTZ level. Based on the excellent agreement between experimental and calculated results, the definite geometry of the pyrimidine cation in the ground electronic state was determined to be a planar structure with C2v symmetry with a decreased N-N distance in the ring.

  18. Analysis of a method for precisely relating a seafloor point to a distant point on land

    NASA Technical Reports Server (NTRS)

    Spiess, F. N.; Lowenstein, C. D.; Mcintyre, M. O.

    1985-01-01

    A study of the environmental constraints and engineering aspects of the acoustic portion of a system for making geodetic ties between undersea reference points and others on land is described. Important areas in which to make such observations initially would be from the California mainland out to oceanic points seaward of the San Andreas fault, and across the Aleutian Trench. The overall approach would be to operate a GPS receiver in a relative positioning (interferometric) mode to provide the long range element of the baseline determination (10 to 1,000 km) and an array of precision sea floor acoustic transponders to link the locally moving sea surface GPS antenna location to a fixed sea floor point. Analyses of various environmental constrants (tides, waves, currents, sound velocity variations) lead to the conclusion that, if one uses a properly designed transponder having a remotely controllable precise retransmission time delay, and is careful with regard to methods for installing these on the sea floor, one should, in many ocean locations, be able to achieve sub-decimeter overall system accuracy. Achievements of cm accuracy or better will require additional understanding of time and space scales of variation of sound velocity structure in the ocean at relevant locations.

  19. The validation analysis of the INSHORE system--a precise and efficient coastal survey system.

    PubMed

    Baganha Baptista, Paulo Renato; Bernardes, Cristina; Cunha, Telmo R

    2011-08-01

    Government and environmental entities are becoming increasingly concerned with qualifying and quantifying the erosion effects that are observed in sandy shores. Correspondingly, survey methodologies that gather data for such erosion studies are increasingly being demanded. The responsible entities are continually broadening their areas of interest, are concerned in the establishment of regular monitoring programmes and are demanding high accuracy from the geo-spatial data that is collected. The budget available for such monitoring activities, however, does not parallel the trend in the increasing demand for quality specifications. Survey methodologies need improvement to meet these requirements. We have developed a new land-based survey system--the INSHORE system--that is ideal for low cost, highly efficient and highly precise coastal surveys. The INSHORE system uses hi-tech hardware that is based on high-grade global positioning system (GPS) receivers and a laser distance sensor combined with advanced software algorithms. This system enables the determination of the ground coordinates of the surveyed areas with a precision of 1 to 2 cm, without having a sensor in contact with the ground surface. The absence of physical contact with the ground makes this system suitable for high-efficiency surveys. The accuracy of the positioning, which is based on advanced differential GPS processing, is enhanced by considering the estimated attitude of the GPS receiver holding structure and eliminates undesirable offsets. This paper describes the INSHORE survey system and presents the results of validation tests that were performed in a sandy shore environment.

  20. Towards Precision Medicine: Advances in Computational Approaches for the Analysis of Human Variants

    PubMed Central

    Peterson, Thomas A; Doughty, Emily; Kann, Maricel G

    2013-01-01

    Variations and similarities in our individual genomes are part of our history, our heritage, and our identity. Some human genomic variants are associated with common traits such as hair and eye color, while others are associated with susceptibility to disease or response to drug treatment. Identifying the human variations producing clinically relevant phenotypic changes is critical for providing accurate and personalized diagnosis, prognosis, and treatment for diseases. Furthermore, a better understanding of the molecular underpinning of disease can lead to development of new drug targets for precision medicine. Several resources have been designed for collecting and storing human genomic variations in highly structured, easily accessible databases. Unfortunately, a vast amount of information about these genetic variants and their functional and phenotypic associations is currently buried in the literature, only accessible by manual curation or sophisticated text mining technology to extract the relevant information. In addition, the low cost of sequencing technologies coupled with increasing computational power has enabled the development of numerous computational methodologies to predict the pathogenicity of human variants. This review provides a detailed comparison of current human variant resources, including HGMD, OMIM, ClinVar, and UniProt/Swiss-Prot, followed by an overview of the computational methods and techniques used to leverage the available data to predict novel deleterious variants. We expect these resources and tools to become the foundation for understanding the molecular details of genomic variants leading to disease, which in turn will enable the promise of precision medicine. PMID:23962656

  1. Precision cleaning verification of fluid components by air/water impingement and total carbon analysis

    NASA Technical Reports Server (NTRS)

    Barile, Ronald G.; Fogarty, Chris; Cantrell, Chris; Melton, Gregory S.

    1994-01-01

    NASA personnel at Kennedy Space Center's Material Science Laboratory have developed new environmentally sound precision cleaning and verification techniques for systems and components found at the center. This technology is required to replace existing methods traditionally employing CFC-113. The new patent-pending technique of precision cleaning verification is for large components of cryogenic fluid systems. These are stainless steel, sand cast valve bodies with internal surface areas ranging from 0.2 to 0.9 sq m. Extrapolation of this technique to components of even larger sizes (by orders of magnitude) is planned. Currently, the verification process is completely manual. In the new technique, a high velocity, low volume water stream impacts the part to be verified. This process is referred to as Breathing Air/Water Impingement and forms the basis for the Impingement Verification System (IVS). The system is unique in that a gas stream is used to accelerate the water droplets to high speeds. Water is injected into the gas stream in a small, continuous amount. The air/water mixture is then passed through a converging/diverging nozzle where the gas is accelerated to supersonic velocities. These droplets impart sufficient energy to the precision cleaned surface to place non-volatile residue (NVR) contaminants into suspension in the water. The sample water is collected and its NVR level is determined by total organic carbon (TOC) analysis at 880 C. The TOC, in ppm carbon, is used to establish the NVR level. A correlation between the present gravimetric CFC113 NVR and the IVS NVR is found from experimental sensitivity factors measured for various contaminants. The sensitivity has the units of ppm of carbon per mg/sq ft of contaminant. In this paper, the equipment is described and data are presented showing the development of the sensitivity factors from a test set including four NVRs impinged from witness plates of 0.05 to 0.75 sq m.

  2. Precision Cleaning Verification of Fluid Components by Air/Water Impingement and Total Carbon Analysis

    NASA Technical Reports Server (NTRS)

    Barile, Ronald G.; Fogarty, Chris; Cantrell, Chris; Melton, Gregory S.

    1995-01-01

    NASA personnel at Kennedy Space Center's Material Science Laboratory have developed new environmentally sound precision cleaning and verification techniques for systems and components found at the center. This technology is required to replace existing methods traditionally employing CFC-113. The new patent-pending technique of precision cleaning verification is for large components of cryogenic fluid systems. These are stainless steel, sand cast valve bodies with internal surface areas ranging from 0.2 to 0.9 m(exp 2). Extrapolation of this technique to components of even larger sizes (by orders of magnitude) is planned. Currently, the verification process is completely manual. In the new technique, a high velocity, low volume water stream impacts the part to be verified. This process is referred to as Breathing Air/Water Impingement and forms the basis for the Impingement Verification System (IVS). The system is unique in that a gas stream is used to accelerate the water droplets to high speeds. Water is injected into the gas stream in a small, continuous amount. The air/water mixture is then passed through a converging-diverging nozzle where the gas is accelerated to supersonic velocities. These droplets impart sufficient energy to the precision cleaned surface to place non-volatile residue (NVR) contaminants into suspension in the water. The sample water is collected and its NVR level is determined by total organic carbon (TOC) analysis at 880 C. The TOC, in ppm carbon, is used to establish the NVR level. A correlation between the present gravimetric CFC-113 NVR and the IVS NVR is found from experimental sensitivity factors measured for various contaminants. The sensitivity has the units of ppm of carbon per mg-ft(exp 2) of contaminant. In this paper, the equipment is described and data are presented showing the development of the sensitivity factors from a test set including four NVR's impinged from witness plates of 0.05 to 0.75 m(exp 2).

  3. Precision Cleaning Verification of Fluid Components by Air/Water Impingement and Total Carbon Analysis

    NASA Technical Reports Server (NTRS)

    Barile, Ronald G.; Fogarty, Chris; Cantrell, Chris; Melton, Gregory S.

    1995-01-01

    NASA personnel at Kennedy Space Center's Material Science Laboratory have developed new environmentally sound precision cleaning and verification techniques for systems and components found at the center. This technology is required to replace existing methods traditionally employing CFC-113. The new patent-pending technique of precision cleaning verification is for large components of cryogenic fluid systems. These are stainless steel, sand cast valve bodies with internal surface areas ranging from 0.2 to 0.9 m(exp 2). Extrapolation of this technique to components of even larger sizes (by orders of magnitude) is planned. Currently, the verification process is completely manual. In the new technique, a high velocity, low volume water stream impacts the part to be verified. This process is referred to as Breathing Air/Water Impingement and forms the basis for the Impingement Verification System (IVS). The system is unique in that a gas stream is used to accelerate the water droplets to high speeds. Water is injected into the gas stream in a small, continuous amount. The air/water mixture is then passed through a converging-diverging nozzle where the gas is accelerated to supersonic velocities. These droplets impart sufficient energy to the precision cleaned surface to place non-volatile residue (NVR) contaminants into suspension in the water. The sample water is collected and its NVR level is determined by total organic carbon (TOC) analysis at 880 C. The TOC, in ppm carbon, is used to establish the NVR level. A correlation between the present gravimetric CFC-113 NVR and the IVS NVR is found from experimental sensitivity factors measured for various contaminants. The sensitivity has the units of ppm of carbon per mg-ft(exp 2) of contaminant. In this paper, the equipment is described and data are presented showing the development of the sensitivity factors from a test set including four NVR's impinged from witness plates of 0.05 to 0.75 m(exp 2).

  4. Optimization Techniques for Improving the Precision of Isotopic Analysis by Thermal Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, G. Q.; Xu, J. F.; Wu-Yang, S. Q.

    2016-12-01

    Operation of instruments and preparation of samples are also significant factors that can affect the precision of TIMS analyses, in addition to instrument hardware. We have reviewed the isotopic data of several standard materials at our TIMS lab for 5 years. It is suggested that several optimization techniques should be used in order to obtain high-precision isotopic ratio data: (1) It is important to choose a suitable filament material for isotopic measurements. We have established that W filament is likely the most efficient for ionizing Sr when selecting from W, Re, and Ta; meanwhile, Re filament can produce a higher intensity for Nd isotopes than W and Ta filament can. It is concluded that the best TIMS signals are obtained for Sr using W signal-filaments and for Nd using Re double-filaments. (2) The preparation of the activator plays a key role in the analysis of some isotopic ratios. This study indicates that choosing a suitable activator can greatly elevate the precision of 206Pb/204Pb ratios during Pb isotopic measurements. We have suggested a new scheme to make an activator by using a mixture of 10% Si-gel + 7.5% H3PO3 + 82.5% H2O (weight %). (3) It is necessary to re-set the cup configuration to avoid cup degradation when operating for a long period of time (a year or more). We propose a new cup configuration to avoid this disadvantage during Sr isotopic analyses. (4) The contamination of 187Re and 185Re after using Re-filament could be eliminated by cleaning the ion source and baking the source housing.

  5. High-precision frequency measurements: indispensable tools at the core of the molecular-level analysis of complex systems

    PubMed Central

    Ruecker, C.; Meringer, M.; Gugisch, R.; Frommberger, M.; Perdue, E. M.; Witt, M.; Schmitt-Kopplin, P.

    2007-01-01

    This perspective article provides an assessment of the state-of-the-art in the molecular-resolution analysis of complex organic materials. These materials can be divided into biomolecules in complex mixtures (which are amenable to successful separation into unambiguously defined molecular fractions) and complex nonrepetitive materials (which cannot be purified in the conventional sense because they are even more intricate). Molecular-level analyses of these complex systems critically depend on the integrated use of high-performance separation, high-resolution organic structural spectroscopy and mathematical data treatment. At present, only high-precision frequency-derived data exhibit sufficient resolution to overcome the otherwise common and detrimental effects of intrinsic averaging, which deteriorate spectral resolution to the degree of bulk-level rather than molecular-resolution analysis. High-precision frequency measurements are integral to the two most influential organic structural spectroscopic methods for the investigation of complex materials—NMR spectroscopy (which provides unsurpassed detail on close-range molecular order) and FTICR mass spectrometry (which provides unrivalled resolution)—and they can be translated into isotope-specific molecular-resolution data of unprecedented significance and richness. The quality of this standalone de novo molecular-level resolution data is of unparalleled mechanistic relevance and is sufficient to fundamentally advance our understanding of the structures and functions of complex biomolecular mixtures and nonrepetitive complex materials, such as natural organic matter (NOM), aerosols, and soil, plant and microbial extracts, all of which are currently poorly amenable to meaningful target analysis. The discrete analytical volumetric pixel space that is presently available to describe complex systems (defined by NMR, FT mass spectrometry and separation technologies) is in the range of 108–14 voxels, and is

  6. Progress on a higher precision measurement of the n =2 triplet P fine structure of atomic helium

    NASA Astrophysics Data System (ADS)

    Davidson, E. B.; Kato, K.; Beica, H.; George, M. C.; Vutha, A. C.; Weel, M.; Storry, C. H.; Hessels, E. A.

    2013-05-01

    Precision measurement of the 23P fine structure of atomic helium, when combined with precise theory, can be used to determine the value of the fine-structure constant. We report on progress towards an improved measurement using a new technique which reduces systematic effects, while improving the signal-to-noise ratio. An intense beam of 23S metastable helium atoms is created in a hollow-cathode liquid-nitrogen-cooled DC-discharge source. The atoms are laser excited to the 23P state and microwave transitions are driven between the 23P states using the Ramsey method of separated oscillatory fields (SOF). Atoms which complete the SOF sequence are shelved into the 23S m =-1 metastable state using laser transitions through the 33S state. These m =-1 atoms can be detected with high efficiency.

  7. Precise Lifetime Measurements in Light Nuclei for Benchmarking Modern Ab-initio Nuclear Structure Models

    SciTech Connect

    Lister, C.J.; McCutchan, E.A.

    2014-06-15

    A new generation of ab-initio calculations, based on realistic two- and three-body forces, is having a profound impact on our view of how nuclei work. To improve the numerical methods, and the parameterization of 3-body forces, new precise data are needed. Electromagnetic transitions are very sensitive to the dynamics which drive mixing between configurations. We have made a series of precise (< 3%) measurements of electromagnetic transitions in the A=10 nuclei {sup 10}C and {sup 10}Be by using the Doppler Shift Attenuation method carefully. Many interesting features can be reproduced including the strong α clustering. New measurements on {sup 8}Be and {sup 12}Be highlight the interplay between the alpha clusters and their valence neutrons.

  8. Precision grid survey apparatus and method for the mapping of hidden ferromagnetic structures

    DOEpatents

    von Wimmerspeg, Udo

    2004-11-16

    The present invention is for a precision grid surveyor having a stationary unit and a roving unit. The stationary unit has a light source unit that emits a light beam and a rotator to project the light beam toward detectors on a roving unit. The roving unit moves over an area to be surveyed. Further the invention is for a method of mapping details of hidden underground iron pipelines, and more particularly the location of bell joints.

  9. Technical Note: An improved guideline for rapid and precise sample preparation of tree-ring stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Schollaen, K.; Baschek, H.; Heinrich, I.; Helle, G.

    2015-07-01

    The procedure of wood sample preparation, including tree-ring dissection, cellulose extraction, homogenization and finally weighing and packing for stable isotope analysis is labour intensive and time consuming. We present an elaborated methodical guideline from pre-analyses considerations, wood sample preparation through semi-automated chemical extraction of cellulose directly from tree-ring cross-sections to tree-ring dissection for high-precision isotope ratio mass spectrometry. This guideline reduces time and maximizes the tree-ring stable isotope data throughput significantly. The method was applied to ten different tree species (coniferous and angiosperm wood) with different wood growth rates and differently shaped tree-ring boundaries. The tree-ring structures of the cellulose cross-sections largely remained well identifiable. FTIR (Fourier transform infrared) spectrometry and the comparison of stable isotope values with classical method confirm chemical purity of the resultant cellulose. Sample homogenization is no longer necessary. Cellulose extraction is now faster, cheaper and more user friendly allowing (i) the simultaneous treatment of wood cross-sections of a total length of 180 cm (equivalent to 6 increment cores of 30 cm length) and thickness of 0.5 to 2 mm, and (ii) precise tree-ring separation at annual to high-resolution scale utilizing manual devices or UV-laser microdissection microscopes.

  10. Extending the analysis of electroweak precision constraints in composite Higgs models

    NASA Astrophysics Data System (ADS)

    Ghosh, Diptimoy; Salvarezza, Matteo; Senia, Fabrizio

    2017-01-01

    In this paper we present a detailed analysis of the Electroweak Precision Observables (EWPO) in composite Higgs models based on the coset SO (5) / SO (4). In our study we include both the fermionic top partners and the spin-1 resonances and consider their possible interplay as well. In order to achieve calculability we use the assumptions of i) partial Ultra Violet Completion (PUVC) following [1] and, ii) absence of sizable effects from physics above the cut-off. Apart from the EWPO, we also take into account the constraints from the top quark, Z and the Higgs boson masses whenever they can be predicted in terms of the model parameters. After presenting our analytic results (often, in certain limits) and discussing their symmetry properties, we also perform detailed fits of the model parameters following the Bayesian approach. We show the posterior probability distributions of the parameters in various scenarios and provide with analytic understanding whenever possible. We find that in certain cases the EWPO allow the compositeness scale to lie well below 1 TeV. Moreover, fermionic top partners of mass around 1 TeV and spin-1 resonances of mass around 2-3 TeV are consistent with the precision data.

  11. Tendency for interlaboratory precision in the GMO analysis method based on real-time PCR.

    PubMed

    Kodama, Takashi; Kurosawa, Yasunori; Kitta, Kazumi; Naito, Shigehiro

    2010-01-01

    The Horwitz curve estimates interlaboratory precision as a function only of concentration, and is frequently used as a method performance criterion in food analysis with chemical methods. The quantitative biochemical methods based on real-time PCR require an analogous criterion to progressively promote method validation. We analyzed the tendency of precision using a simplex real-time PCR technique in 53 collaborative studies of seven genetically modified (GM) crops. Reproducibility standard deviation (SR) and repeatability standard deviation (Sr) of the genetically modified organism (GMO) amount (%) was more or less independent of GM crops (i.e., maize, soybean, cotton, oilseed rape, potato, sugar beet, and rice) and evaluation procedure steps. Some studies evaluated whole steps consisting of DNA extraction and PCR quantitation, whereas others focused only on the PCR quantitation step by using DNA extraction solutions. Therefore, SR and Sr for GMO amount (%) are functions only of concentration similar to the Horwitz curve. We proposed S(R) = 0.1971C 0.8685 and S(r) = 0.1478C 0.8424, where C is the GMO amount (%). We also proposed a method performance index in GMO quantitative methods that is analogous to the Horwitz Ratio.

  12. Evaluation of a 202Pb-205Pb double spike for high - precision lead isotope analysis

    NASA Astrophysics Data System (ADS)

    Todt, W.; Cliff, R. A.; Hanser, A.; Hofmann, A. W.

    A highly enriched 202Pb +205Pb double-spike (202Pb/204Pb = 41000) has been prepared and used to make measurements of lead isotopic composition with internal correction for fractionation. The ratio of 205Pb/202Pb = 0.227388 in the double spike was calibrated against the certificate abundances of 208Pb and 206Pb in NBS standard SRM-982. The effectiveness of the double spike in improving the precision of lead isotopic analysis was tested by a series of measurements of double-spiked SRM 981. These demonstrate substantial improvements in precision with standard deviations ranging from 70 to 150 ppm. Measurements were made in static mode using a Finnigan MAT-261 mass spectrometer, recently fitted with 9 new faraday cups, which allows simultaneous monitoring of all lead peaks plus the reference masses (203 and 201) for isobaric interference from thallium and BaPO2. New mutually consistent calibrations of the lead isotopic composition of the NBS lead standards SRM 981 and SRM 982 have been calculated from the double spiked measurements. In general, the new results agree closely with the certificate values, but a small difference in 208Pb abundance in SRM 981, previously observed by others and ourselves, has been confirmed.

  13. High-precision isothermal titration calorimetry with automated peak-shape analysis.

    PubMed

    Keller, Sandro; Vargas, Carolyn; Zhao, Huaying; Piszczek, Grzegorz; Brautigam, Chad A; Schuck, Peter

    2012-06-05

    Isothermal titration calorimetry (ITC) is a powerful classical method that enables researchers in many fields to study the thermodynamics of molecular interactions. Primary ITC data comprise the temporal evolution of differential power reporting the heat of reaction during a series of injections of aliquots of a reactant into a sample cell. By integration of each injection peak, an isotherm can be constructed of total changes in enthalpy as a function of changes in solution composition, which is rich in thermodynamic information on the reaction. However, the signals from the injection peaks are superimposed by the stochastically varying time-course of the instrumental baseline power, limiting the precision of ITC isotherms. Here, we describe a method for automated peak assignment based on peak-shape analysis via singular value decomposition in combination with detailed least-squares modeling of local pre- and postinjection baselines. This approach can effectively filter out contributions of short-term noise and adventitious events in the power trace. This method also provides, for the first time, statistical error estimates for the individual isotherm data points. In turn, this results in improved detection limits for high-affinity or low-enthalpy binding reactions and significantly higher precision of the derived thermodynamic parameters.

  14. The use of alternative forms of graphical analysis to balance bias and precision in PET images

    PubMed Central

    Logan, Jean; Alexoff, David; Fowler, Joanna S

    2011-01-01

    Graphical analysis (GA) is an efficient method for estimating total tissue distribution volume (VT) from positron emission tomography (PET) uptake data. The original GA produces a negative bias in VT in the presence of noise. Estimates of VT using other GA forms have less bias but less precision. Here, we show how the bias terms are related between the GA methods and how using an instrumental variable (IV) can also reduce bias. Results are based on simulations of a two-compartment model with VT's ranging from 10.5 to 64 mL/cm3 and from PET image data with the tracer [11C]DASB ([11C]-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl) benzonitrile). Four estimates of VT (or distribution volume ratio (DVR) using a reference tissue) can be easily computed from different formulations of GA including the IV. As noise affects the estimates from all four differently, they generally do not provide the same estimates. By taking the median value of the four estimates, we can decrease the bias and reduce the effect of large values contributing to noisy images. The variance of the four estimates can serve as a guide to the reliability of the median estimate. This may provide a general method for the generation of parametric images with little bias and good precision. PMID:20808318

  15. The use of alternative forms of graphical analysis to balance bias and precision in PET images.

    PubMed

    Logan, Jean; Alexoff, David; Fowler, Joanna S

    2011-02-01

    Graphical analysis (GA) is an efficient method for estimating total tissue distribution volume (V(T)) from positron emission tomography (PET) uptake data. The original GA produces a negative bias in V(T) in the presence of noise. Estimates of V(T) using other GA forms have less bias but less precision. Here, we show how the bias terms are related between the GA methods and how using an instrumental variable (IV) can also reduce bias. Results are based on simulations of a two-compartment model with V(T)'s ranging from 10.5 to 64 mL/cm(3) and from PET image data with the tracer [(11)C]DASB ([(11)C]-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl) benzonitrile). Four estimates of V(T) (or distribution volume ratio (DVR) using a reference tissue) can be easily computed from different formulations of GA including the IV. As noise affects the estimates from all four differently, they generally do not provide the same estimates. By taking the median value of the four estimates, we can decrease the bias and reduce the effect of large values contributing to noisy images. The variance of the four estimates can serve as a guide to the reliability of the median estimate. This may provide a general method for the generation of parametric images with little bias and good precision.

  16. Closed tubes preparation of graphite for high-precision AMS radiocarbon analysis

    NASA Astrophysics Data System (ADS)

    Hajdas, I.; Michczynska, D.; Bonani, G.; Maurer, M.; Wacker, L.

    2009-04-01

    Radiocarbon dating is an established tool applied in Geochronology. Technical developments of Accelerator Mass Spectrometry AMS, which allow measurements of samples containing less than 1 mg of carbon, opened opportunities for new applications. Moreover, high resolution records of the past changes require high-resolution chronologies i.e. sampling for 14C dating. In result, the field of applications is rapidly expanding and number of radiocarbon analysis is growing rapidly. Nowadays dedicated 14C AMS machines have great capacity for analysis but in order to keep up with the demand for analysis and provide the results as fast as possible a very efficient way of sample preparation is required. Sample preparation for 14C AMS analysis consists of two steps: separation of relevant carbon from the sample material (removing contamination) and preparation of graphite for AMS analysis. The last step usually involves reaction of CO2 with H2, in the presence of metal catalyst (Fe or Co) of specific mesh size heated to 550-625°C, as originally suggested by Vogel et al. (1984). Various graphitization systems have been built in order to fulfil the requirement of sample quality needed for high-precision radiocarbon data. In the early 90ties another method has been proposed (Vogel 1992) and applied by few laboratories mainly for environmental or biomedical samples. This method uses TiH2 as a source of H2 and can be easily and flexibly applied to produce graphite. Sample of CO2 is frozen in to the tube containing pre-conditioned Zn/TiH2 and Fe catalyst. Torch sealed tubes are then placed in the stepwise heated oven at 500/550°C and left to react for several hours. The greatest problem is the lack of control of the reaction completeness and considerable fractionation. However, recently reported results (Xu et al. 2007) suggest that high precision dating using graphite produced in closed tubes might be possible. We will present results of radiocarbon dating of the set of standards

  17. Precise terrestrial time: A means for improved ballistic missile guidance analysis

    NASA Technical Reports Server (NTRS)

    Ehrsam, E. E.; Cresswell, S. A.; Mckelvey, G. R.; Matthews, F. L.

    1978-01-01

    An approach developed to improve the ground instrumentation time tagging accuracy and adapted to support the Minuteman ICBM program is desired. The Timing Insertion Unit (TIU) technique produces a telemetry data time tagging resolution of one tenth of a microsecond, with a relative intersite accuracy after corrections and velocity data (range, azimuth, elevation and range rate) also used in missile guidance system analysis can be correlated to within ten microseconds of the telemetry guidance data. This requires precise timing synchronization between the metric and telemetry instrumentation sites. The timing synchronization can be achieved by using the radar automatic phasing system time correlation methods. Other time correlation techniques such as Television (TV) Line-10 and the Geostationary Operational Environmental Satellites (GEOS) terrestial timing receivers are also considered.

  18. An Image Analysis Method for the Precise Selection and Quantitation of Fluorescently Labeled Cellular Constituents

    PubMed Central

    Agley, Chibeza C.; Velloso, Cristiana P.; Lazarus, Norman R.

    2012-01-01

    The accurate measurement of the morphological characteristics of cells with nonuniform conformations presents difficulties. We report here a straightforward method using immunofluorescent staining and the commercially available imaging program Adobe Photoshop, which allows objective and precise information to be gathered on irregularly shaped cells. We have applied this measurement technique to the analysis of human muscle cells and their immunologically marked intracellular constituents, as these cells are prone to adopting a highly branched phenotype in culture. Use of this method can be used to overcome many of the long-standing limitations of conventional approaches for quantifying muscle cell size in vitro. In addition, wider applications of Photoshop as a quantitative and semiquantitative tool in immunocytochemistry are explored. PMID:22511600

  19. Breakpoint analysis: Precise localization of genetic markers by means of nonstatistical computation using relatively few genotypes

    SciTech Connect

    Elsner, T.I.; Albertsen, H.; Gerken, S.C.; Cartwright, P.; White, R.

    1995-02-01

    Placing new markers on a previously existing genetic map by using conventional methods of multilocus linkage analysis requires that a large number of reference families be genotyped. This paper presents a methodology for placing new markers on existing genetic maps by genotyping only a few individuals in a selected subset of the reference panel. We show that by identifying meiotic breakpoint events within existing genetic maps and genotyping individuals who exhibit these events, along with one nonrecombinant sibling and their parents, we can determine precise locations for new markers even within subcentimorgan chromosomal regions. This method also improves detection of errors in genotyping and assists in the observation of chromosome behavior in specific regions. 31 refs., 9 figs.

  20. Using frequency analysis to improve the precision of human body posture algorithms based on Kalman filters.

    PubMed

    Olivares, Alberto; Górriz, J M; Ramírez, J; Olivares, G

    2016-05-01

    With the advent of miniaturized inertial sensors many systems have been developed within the last decade to study and analyze human motion and posture, specially in the medical field. Data measured by the sensors are usually processed by algorithms based on Kalman Filters in order to estimate the orientation of the body parts under study. These filters traditionally include fixed parameters, such as the process and observation noise variances, whose value has large influence in the overall performance. It has been demonstrated that the optimal value of these parameters differs considerably for different motion intensities. Therefore, in this work, we show that, by applying frequency analysis to determine motion intensity, and varying the formerly fixed parameters accordingly, the overall precision of orientation estimation algorithms can be improved, therefore providing physicians with reliable objective data they can use in their daily practice.

  1. Slight pressure imbalances can affect accuracy and precision of dual inlet-based clumped isotope analysis.

    PubMed

    Fiebig, Jens; Hofmann, Sven; Löffler, Niklas; Lüdecke, Tina; Methner, Katharina; Wacker, Ulrike

    2016-01-01

    It is well known that a subtle nonlinearity can occur during clumped isotope analysis of CO2 that - if remaining unaddressed - limits accuracy. The nonlinearity is induced by a negative background on the m/z 47 ion Faraday cup, whose magnitude is correlated with the intensity of the m/z 44 ion beam. The origin of the negative background remains unclear, but is possibly due to secondary electrons. Usually, CO2 gases of distinct bulk isotopic compositions are equilibrated at 1000 °C and measured along with the samples in order to be able to correct for this effect. Alternatively, measured m/z 47 beam intensities can be corrected for the contribution of secondary electrons after monitoring how the negative background on m/z 47 evolves with the intensity of the m/z 44 ion beam. The latter correction procedure seems to work well if the m/z 44 cup exhibits a wider slit width than the m/z 47 cup. Here we show that the negative m/z 47 background affects precision of dual inlet-based clumped isotope measurements of CO2 unless raw m/z 47 intensities are directly corrected for the contribution of secondary electrons. Moreover, inaccurate results can be obtained even if the heated gas approach is used to correct for the observed nonlinearity. The impact of the negative background on accuracy and precision arises from small imbalances in m/z 44 ion beam intensities between reference and sample CO2 measurements. It becomes the more significant the larger the relative contribution of secondary electrons to the m/z 47 signal is and the higher the flux rate of CO2 into the ion source is set. These problems can be overcome by correcting the measured m/z 47 ion beam intensities of sample and reference gas for the contributions deriving from secondary electrons after scaling these contributions to the intensities of the corresponding m/z 49 ion beams. Accuracy and precision of this correction are demonstrated by clumped isotope analysis of three internal carbonate standards. The

  2. Program for Nonlinear Structural Analysis

    DTIC Science & Technology

    1981-09-01

    November 1970. 2. R. E. Jones and W. L. Salus , "Survey and Development of Finite Elements for Nonlineer Structural Analysis", Volume II, "Nonlinear Shell...1970. 2. R. E. Jones and W. L. Salus , "Survey and Development of Finite Elements for Nonlinear Structural Analysis," Volume II, "Nonlinear Shell

  3. Unscented predictive variable structure filter for satellite attitude estimation with model errors when using low precision sensors

    NASA Astrophysics Data System (ADS)

    Cao, Lu; Li, Hengnian

    2016-10-01

    For the satellite attitude estimation problem, the serious model errors always exist and hider the estimation performance of the Attitude Determination and Control System (ACDS), especially for a small satellite with low precision sensors. To deal with this problem, a new algorithm for the attitude estimation, referred to as the unscented predictive variable structure filter (UPVSF) is presented. This strategy is proposed based on the variable structure control concept and unscented transform (UT) sampling method. It can be implemented in real time with an ability to estimate the model errors on-line, in order to improve the state estimation precision. In addition, the model errors in this filter are not restricted only to the Gaussian noises; therefore, it has the advantages to deal with the various kinds of model errors or noises. It is anticipated that the UT sampling strategy can further enhance the robustness and accuracy of the novel UPVSF. Numerical simulations show that the proposed UPVSF is more effective and robustness in dealing with the model errors and low precision sensors compared with the traditional unscented Kalman filter (UKF).

  4. Geotechnical parameter spatial distribution stochastic analysis based on multi-precision information assimilation

    NASA Astrophysics Data System (ADS)

    Wang, C.; Rubin, Y.

    2014-12-01

    Spatial distribution of important geotechnical parameter named compression modulus Es contributes considerably to the understanding of the underlying geological processes and the adequate assessment of the Es mechanics effects for differential settlement of large continuous structure foundation. These analyses should be derived using an assimilating approach that combines in-situ static cone penetration test (CPT) with borehole experiments. To achieve such a task, the Es distribution of stratum of silty clay in region A of China Expo Center (Shanghai) is studied using the Bayesian-maximum entropy method. This method integrates rigorously and efficiently multi-precision of different geotechnical investigations and sources of uncertainty. Single CPT samplings were modeled as a rational probability density curve by maximum entropy theory. Spatial prior multivariate probability density function (PDF) and likelihood PDF of the CPT positions were built by borehole experiments and the potential value of the prediction point, then, preceding numerical integration on the CPT probability density curves, the posterior probability density curve of the prediction point would be calculated by the Bayesian reverse interpolation framework. The results were compared between Gaussian Sequential Stochastic Simulation and Bayesian methods. The differences were also discussed between single CPT samplings of normal distribution and simulated probability density curve based on maximum entropy theory. It is shown that the study of Es spatial distributions can be improved by properly incorporating CPT sampling variation into interpolation process, whereas more informative estimations are generated by considering CPT Uncertainty for the estimation points. Calculation illustrates the significance of stochastic Es characterization in a stratum, and identifies limitations associated with inadequate geostatistical interpolation techniques. This characterization results will provide a multi-precision

  5. Omics AnalySIs System for PRecision Oncology (OASISPRO): A Web-based Omics Analysis Tool for Clinical Phenotype Prediction.

    PubMed

    Yu, Kun-Hsing; Fitzpatrick, Michael R; Pappas, Luke; Chan, Warren; Kung, Jessica; Snyder, Michael

    2017-09-12

    Precision oncology is an approach that accounts for individual differences to guide cancer management. Omics signatures have been shown to predict clinical traits for cancer patients. However, the vast amount of omics information poses an informatics challenge in systematically identifying patterns associated with health outcomes, and no general-purpose data-mining tool exists for physicians, medical researchers, and citizen scientists without significant training in programming and bioinformatics. To bridge this gap, we built the Omics AnalySIs System for PRecision Oncology (OASISPRO), a web-based system to mine the quantitative omics information from The Cancer Genome Atlas (TCGA). This system effectively visualizes patients' clinical profiles, executes machine-learning algorithms of choice on the omics data, and evaluates the prediction performance using held-out test sets. With this tool, we successfully identified genes strongly associated with tumor stage, and accurately predicted patients' survival outcomes in many cancer types, including mesothelioma and adrenocortical carcinoma. By identifying the links between omics and clinical phenotypes, this system will facilitate omics studies on precision cancer medicine and contribute to establishing personalized cancer treatment plans. This web-based tool is available at http://tinyurl.com/oasispro ;source codes are available at http://tinyurl.com/oasisproSourceCode .

  6. Integrated data analysis in the age of precision spectroscopy: the ESPRESSO case

    NASA Astrophysics Data System (ADS)

    Cupani, Guido; D'Odorico, Valentina; Cristiani, Stefano; González-Hernández, Jonay I.; Lovis, Christophe; Sousa, Sérgio; Calderone, Giorgio; Cirami, Roberto; Di Marcantonio, Paolo; Mégevand, Denis

    2016-07-01

    The Echelle SPectrograph for Rocky Exoplanets and Stable Spectral Observations (ESPRESSO) is an ultrastable spectrograph for the coudé-combined focus of the VLT. With its unprecedented capabilities (resolution up to fi 200,000, wavelength range from 380 to 780 nm; centimeter-per-second precision in wavelength calibration), ESPRESSO is a prime example of the now spreading science machine concept: a fully-integrated system carefully designed to perform direct scientific measurements on the data, in a matter of minutes from the execution of the observations. This approach is motivated by the very specific science cases of the instrument (search for terrestrial exoplanets with the radial velocity method; measure of the variation of fundamental constants using the spectral signatures of the inter-galactic medium) and is achieved by a dedicated tool for spectral analysis, the data analysis software or DAS, targeted to both stellar and quasar spectra. In this paper, we describe characteristics and performances of the DAS, with particular emphasis on the novel algorithms for stellar and quasar analysis (continuum fitting and interpretation of the absorption features).

  7. Dilution-of-Precision-Based Lunar Surface Navigation System Analysis Utilizing Lunar Orbiters

    NASA Technical Reports Server (NTRS)

    Welch, Bryan W.; Connolly, Joseph W.; Sands, Obed S.

    2007-01-01

    The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Although navigation systems have already been proven in the Apollo missions to the Moon, the current exploration campaign will involve more extensive and extended missions requiring new concepts for lunar navigation. In contrast to Apollo missions, which were limited to the near-side equatorial region of the Moon, those under the Exploration Systems Initiative will require navigation on the Moon's limb and far side. Since these regions have poor Earth visibility, a navigation system comprised solely of Earth-based tracking stations will not provide adequate navigation solutions in these areas. In this report, a dilution-of-precision (DoP)-based analysis of the performance of a network of Moon orbiting satellites is provided. This analysis extends a previous analysis of a lunar network (LN) of navigation satellites by providing an assessment of the capability associated with a variety of assumptions. These assumptions pertain to the minimum surface user elevation angle and a total single satellite failure in the lunar network. The assessment is accomplished by making appropriately formed estimates of DoP. Different adaptations of DoP, such as geometric DoP and positional DoP (GDoP and PDoP), are associated with a different set of assumptions regarding augmentations to the navigation receiver or transceiver.

  8. Dilution-of-Precision-Based Lunar Surface Navigation System Analysis Utilizing Earth-Based Assets

    NASA Technical Reports Server (NTRS)

    Welch, Bryan W.; Connolly, Joseph W.; Sands, Obed S.

    2007-01-01

    The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Although navigation systems have already been proven in the Apollo missions to the Moon, the current exploration campaign will involve more extensive and extended missions requiring new concepts for lunar navigation. In contrast to Apollo missions, which were limited to the near-side equatorial region of the Moon, those under the Exploration Systems Initiative will require navigation on the Moon's limb and far side. These regions are known to have poor Earth visibility, but unknown is the extent to which a navigation system comprised solely of Earth-based tracking stations will provide adequate navigation solutions in these areas. This report presents a dilution-of-precision (DoP)-based analysis of the performance of a network of Earth-based assets. This analysis extends a previous analysis of a lunar network (LN) of navigation satellites by providing an assessment of the capability associated with a variety of assumptions. These assumptions pertain to the minimum provider elevation angle, nadir and zenith beam widths, and a total single failure in one of the Earth-based assets. The assessment is accomplished by making appropriately formed estimates of DoP. Different adaptations of DoP, such as geometrical DoP and positional DoP (GDoP and PDoP), are associated with a different set of assumptions regarding augmentations to the navigation receiver or transceiver.

  9. Developing web-based data analysis tools for precision farming using R and Shiny

    NASA Astrophysics Data System (ADS)

    Jahanshiri, Ebrahim; Mohd Shariff, Abdul Rashid

    2014-06-01

    Technologies that are set to increase the productivity of agricultural practices require more and more data. Nevertheless, farming data is also being increasingly cheap to collect and maintain. Bulk of data that are collected by the sensors and samples need to be analysed in an efficient and transparent manner. Web technologies have long being used to develop applications that can assist the farmers and managers. However until recently, analysing the data in an online environment has not been an easy task especially in the eyes of data analysts. This barrier is now overcome by the availability of new application programming interfaces that can provide real-time web based data analysis. In this paper developing a prototype web based application for data analysis using new facilities in R statistical package and its web development facility, Shiny is explored. The pros and cons of this type of data analysis environment for precision farming are enumerated and future directions in web application development for agricultural data are discussed.

  10. Gaining Precision and Accuracy on Microprobe Trace Element Analysis with the Multipoint Background Method

    NASA Astrophysics Data System (ADS)

    Allaz, J. M.; Williams, M. L.; Jercinovic, M. J.; Donovan, J. J.

    2014-12-01

    Electron microprobe trace element analysis is a significant challenge, but can provide critical data when high spatial resolution is required. Due to the low peak intensity, the accuracy and precision of such analyses relies critically on background measurements, and on the accuracy of any pertinent peak interference corrections. A linear regression between two points selected at appropriate off-peak positions is a classical approach for background characterization in microprobe analysis. However, this approach disallows an accurate assessment of background curvature (usually exponential). Moreover, if present, background interferences can dramatically affect the results if underestimated or ignored. The acquisition of a quantitative WDS scan over the spectral region of interest is still a valuable option to determine the background intensity and curvature from a fitted regression of background portions of the scan, but this technique retains an element of subjectivity as the analyst has to select areas in the scan, which appear to represent background. We present here a new method, "Multi-Point Background" (MPB), that allows acquiring up to 24 off-peak background measurements from wavelength positions around the peaks. This method aims to improve the accuracy, precision, and objectivity of trace element analysis. The overall efficiency is amended because no systematic WDS scan needs to be acquired in order to check for the presence of possible background interferences. Moreover, the method is less subjective because "true" backgrounds are selected by the statistical exclusion of erroneous background measurements, reducing the need for analyst intervention. This idea originated from efforts to refine EPMA monazite U-Th-Pb dating, where it was recognised that background errors (peak interference or background curvature) could result in errors of several tens of million years on the calculated age. Results obtained on a CAMECA SX-100 "UltraChron" using monazite

  11. Precision Analysis of Point-And Photogrammetric Measurements for Corridor Mapping: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Molina, P.; Blázquez, M.; Sastre, J.; Colomina, I.

    2016-03-01

    This paper addresses the key aspects of the sensor orientation and calibration approach within the mapKITE concept for corridor mapping, focusing on the contribution analysis of point-and-scale measurements of kinematic ground control points. MapKITE is a new mobile, simultaneous terrestrial and aerial, geodata acquisition and post-processing method. On one hand, the acquisition system is a tandem composed of a terrestrial mobile mapping system and an unmanned aerial system, the latter equipped with a remote sensing payload, and linked through a 'virtual tether', that is, a real-time waypoint supply from the terrestrial vehicle to the unmanned aircraft. On the other hand, mapKITE entails a method for geodata post-processing (specifically, sensor orientation and calibration) based on the described acquisition paradigm, focusing on few key aspects: the particular geometric relationship of a mapKITE network - the aerial vehicle always observes the terrestrial one as they both move -, precise air and ground trajectory determination - the terrestrial vehicle is regarded as a kinematic ground control point - and new photogrammetric measurements - pointing on and measuring the scale of an optical target on the roof of the terrestrial vehicle - are exploited. In this paper, we analyze the performance of aerial image orientation and calibration in mapKITE for corridor mapping, which is the natural application niche of mapKITE, based on the principles and procedures of integrated sensor orientation with the addition of point-and-scale photogrammetric measurements of the kinematic ground control points. To do so, traditional (static ground control points, photogrammetric tie points, aerial control) and new (pointing-and-scaling of kinematic ground control points) measurements have been simulated for mapKITE corridor mapping missions, consisting on takeoff and calibration pattern, single-pass corridor operation potentially performing calibration patterns, and landing and

  12. DPTRAJ/ODP - DOUBLE PRECISION TRAJECTORY ANALYSIS AND ORBIT DETERMINATION PROGRAM

    NASA Technical Reports Server (NTRS)

    Breckheimer, P. J.

    1994-01-01

    The Double Precision Trajectory Analysis Program, DPTRAJ, and the Orbit Determination Program, ODP, have been developed and improved over the years to provide the NASA Jet Propulsion Laboratory with a highly reliable and accurate navigation capability for their deep space missions such as VOYAGER. DPTRAJ and ODP are each collections of programs which work together to provide the desired computational results. DPTRAJ, ODP, and their supporting utility programs are capable of handling the massive amounts of data and performing the various numerical calculations required for solving the navigation problems associated with planetary fly-by and lander missions. They were used extensively in support of NASA's VOYAGER project. DPTRAJ produces a spacecraft ephemeris by numerical integration of the equations of motion, which can be formulated using a full set of acceleration models. For each particular trajectory case the extent of the modeling employed and the precision of the integration process are controlled by user input specifications. The equation of motion used includes four types of terms. An acceleration term accounts for the basic conic motion of the spacecraft with respect to the central body. Terms that measure the attraction of the perturbing bodies on the spacecraft and terms that indirectly affect the motion as perturbations on the central body may be included. Terms are also provided to account for other gravitational and non-gravitational effects on the motion. ODP's function is the processing of the observational data in order to compute precise estimates of the spacecraft, or lander, position coordinate histories. This function is executed by processing the observation data and auxiliary calibration information. ODP also computes a spacecraft state vector, or a lander position vector, along with parameters which define the acceleration. The heart of the ODP process is a data fitting subprocess in which validated, edited, and corrected observational data

  13. Post pyrolysis trapping of molecular hydrogen improves precision for δD(CH4) analysis

    NASA Astrophysics Data System (ADS)

    Bock, M.; Schmitt, J.; Schneider, R.; Fischer, H.

    2012-04-01

    Methane (CH4) is the third most important greenhouse gas after water vapour and carbon dioxide (CO2). Since the industrial revolution the mixing ratio of CH4 in the atmosphere rose to ~1800 ppb, a value never reached within the last 800 000 years. This CH4 increase can only be assessed compared to its natural changes in the past. Firn air and air enclosures in polar ice cores represent the only direct paleoatmospheric archive. The latter show that atmospheric CH4 concentrations changed in concert with northern hemisphere temperature during both glacial/interglacial transitions as well as rapid climate changes (Dansgaard-Oeschger events). Since the different sources of atmospheric methane exhibit distinct carbon and hydrogen isotopic composition (δ13CH4 and δD(CH4)) reconstructions of these parameters on ice cores allow to constrain individual CH4 source/sink changes. δD(CH4) also reflects water cycle changes as hydrogen of precipitation is traced into methane produced from wetland/thermokarst/permafrost systems (Bock et al. 2010, Science). Here we present an updated high precision on line gas chromatography pyrolysis isotope ratio monitoring mass spectrometry technique (GC/P/irmMS) for analysis of δD(CH4) extracted from ice cores. It is based on earlier developments (Bock et al. 2010, RCM) and is improved concerning sample size and precision. The main achievement is post pyrolysis trapping (PPT) of molecular hydrogen after the high temperature conversion of methane leading to a better signal to noise ratio. Air from only 350 g of ice with CH4 concentrations as low as 350 ppb can now be measured with a precision of ~2‰. Such ice samples contain only approximately 30 mL of air and less than 1 nmol CH4. The new method was applied on ice samples from the EDML and EDC ice cores (European Project for Ice Coring in Antarctica, Dronning Maud Land, Dome Concordia). We present the first δD(CH4) records covering the penultimate termination and interglacial from EDML

  14. Accurate, precise, and efficient theoretical methods to calculate anion-π interaction energies in model structures.

    PubMed

    Mezei, Pál D; Csonka, Gábor I; Ruzsinszky, Adrienn; Sun, Jianwei

    2015-01-13

    A correct description of the anion-π interaction is essential for the design of selective anion receptors and channels and important for advances in the field of supramolecular chemistry. However, it is challenging to do accurate, precise, and efficient calculations of this interaction, which are lacking in the literature. In this article, by testing sets of 20 binary anion-π complexes of fluoride, chloride, bromide, nitrate, or carbonate ions with hexafluorobenzene, 1,3,5-trifluorobenzene, 2,4,6-trifluoro-1,3,5-triazine, or 1,3,5-triazine and 30 ternary π-anion-π' sandwich complexes composed from the same monomers, we suggest domain-based local-pair natural orbital coupled cluster energies extrapolated to the complete basis-set limit as reference values. We give a detailed explanation of the origin of anion-π interactions, using the permanent quadrupole moments, static dipole polarizabilities, and electrostatic potential maps. We use symmetry-adapted perturbation theory (SAPT) to calculate the components of the anion-π interaction energies. We examine the performance of the direct random phase approximation (dRPA), the second-order screened exchange (SOSEX), local-pair natural-orbital (LPNO) coupled electron pair approximation (CEPA), and several dispersion-corrected density functionals (including generalized gradient approximation (GGA), meta-GGA, and double hybrid density functional). The LPNO-CEPA/1 results show the best agreement with the reference results. The dRPA method is only slightly less accurate and precise than the LPNO-CEPA/1, but it is considerably more efficient (6-17 times faster) for the binary complexes studied in this paper. For 30 ternary π-anion-π' sandwich complexes, we give dRPA interaction energies as reference values. The double hybrid functionals are much more efficient but less accurate and precise than dRPA. The dispersion-corrected double hybrid PWPB95-D3(BJ) and B2PLYP-D3(BJ) functionals perform better than the GGA and meta

  15. Precise Analysis of Gallium Isotopic Composition by MC-ICP-MS.

    PubMed

    Yuan, Wei; Chen, Jiu Bin; Birck, Jean-Louis; Yin, Zuo Ying; Yuan, Sheng Liu; Cai, Hong Ming; Wang, Zhong Wei; Huang, Qiang; Wang, Zhu Hong

    2016-10-04

    Though an isotope approach could be beneficial for better understanding the biogeochemical cycle of gallium (Ga), an analogue of the monoisotopic element aluminum (Al), the geochemistry of Ga isotopes has not been widely elaborated. We developed a two-step method for purifying Ga from geological (biological) samples for precise measurement of Ga isotope ratio using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Ga was thoroughly separated from other matrix elements using two chromatographic columns loaded with AG 1-X4 and Ln-spec resin, respectively. The separation method was carefully calibrated using both synthetic and natural samples and validated by assessing the extraction yield (99.8 ± 0.8%, 2SD, n = 23) and the reproducibility (2SD uncertainty better than 0.05‰, n = 116) of the measured isotopic ratio (expressed as δ(71)Ga). The validation of the whole protocol, together with instrumental analysis, was confirmed by the investigation of the matrix effect, the result of a standard addition experiment, and the comparison of Ga isotope measurement on two mass spectrometers-Nu Plasma II and Neptune Plus. Although the measurements using the sample-standard bracketing (SSB) correction method on both instruments resulted in identical δ(71)Ga values for reference materials, the modified empirical external normalization (MEEN) method gave relatively better precision compared to SSB on Neptune. Our preliminary results showed large variation of δ(71)Ga (up to 1.83‰) for 10 standards, with higher values in industrially produced materials, implying potential application of Ga isotopes.

  16. Precision of Multiple Reaction Monitoring Mass Spectrometry Analysis of Formalin-Fixed, Paraffin-Embedded Tissue

    PubMed Central

    2012-01-01

    We compared the reproducibility of multiple reaction monitoring (MRM) mass spectrometry-based peptide quantitation in tryptic digests from formalin-fixed, paraffin-embedded (FFPE) and frozen clear cell renal cell carcinoma tissues. The analyses targeted a candidate set of 114 peptides previously identified in shotgun proteomic analyses, of which 104 were detectable in FFPE and frozen tissue. Although signal intensities for MRM of peptides from FFPE tissue were on average 66% of those in frozen tissue, median coefficients of variation (CV) for measurements in FFPE and frozen tissues were nearly identical (18–20%). Measurements of lysine C-terminal peptides and arginine C-terminal peptides from FFPE tissue were similarly reproducible (19.5% and 18.3% median CV, respectively). We further evaluated the precision of MRM-based quantitation by analysis of peptides from the Her2 receptor in FFPE and frozen tissues from a Her2 overexpressing mouse xenograft model of breast cancer and in human FFPE breast cancer specimens. We obtained equivalent MRM measurements of HER2 receptor levels in FFPE and frozen mouse xenografts derived from HER2-overexpressing BT474 cells and HER2-negative Sum159 cells. MRM analyses of 5 HER2-positive and 5 HER-negative human FFPE breast tumors confirmed the results of immunohistochemical analyses, thus demonstrating the feasibility of HER2 protein quantification in FFPE tissue specimens. The data demonstrate that MRM analyses can be performed with equal precision on FFPE and frozen tissues and that lysine-containing peptides can be selected for quantitative comparisons, despite the greater impact of formalin fixation on lysine residues. The data further illustrate the feasibility of applying MRM to quantify clinically important tissue biomarkers in FFPE specimens. PMID:22530795

  17. Achieving high-precision pointing on ExoplanetSat: initial feasibility analysis

    NASA Astrophysics Data System (ADS)

    Pong, Christopher M.; Lim, Sungyung; Smith, Matthew W.; Miller, David W.; Villaseñor, Jesus S.; Seager, Sara

    2010-07-01

    ExoplanetSat is a proposed three-unit CubeSat designed to detect down to Earth-sized exoplanets in an orbit out to the habitable zone of Sun-like stars via the transit method. To achieve the required photometric precision to make these measurements, the target star must remain within the same fraction of a pixel, which is equivalent to controlling the pointing of the satellite to the arcsecond level. The satellite will use a two-stage control system: coarse control will be performed by a set of reaction wheels, desaturated by magnetic torque coils, and fine control will be performed by a piezoelectric translation stage. Since no satellite of this size has previously demonstrated this high level of pointing precision, a simulation has been developed to prove the feasibility of realizing such a system. The current baseline simulation has demonstrated the ability to hold the target star to within 0.05 pixels or 1.8 arcseconds (with an 85 mm lens and 15 μm pixels), in the presence of large reaction wheel disturbances as well as external environmental disturbances. This meets the current requirement of holding the target star to 0.14 pixels or 5.0 arcseconds. Other high-risk aspects of the design have been analyzed such as the effect of changing the guide star centroiding error, changing the CMOS sampling frequency, and reaction wheel selection on the slew performance of the satellite. While these results are promising as an initial feasibility analysis, further model improvements and hardware-in-the-loop tests are currently underway.

  18. The Structure of Light Nuclei and Its Effect on Precise Atomic Measurements

    NASA Astrophysics Data System (ADS)

    Friar, James L.

    This review consists of three parts: (a) what every atomic physicist needs to know about the physics of light nuclei; (b) what nuclear physicists can do for atomic physics; (c) what atomic physicists can do for nuclear physics. A brief qualitative overview of the nuclear force and calculational techniques for light nuclei will be presented, with an emphasis on debunking myths and on recent progress in the field. Nuclear quantities that affect precise atomic measurements will be discussed, together with their current theoretical and experimental status. The final topic will be a discussion of those atomic measurements that would be useful to nuclear physics, and nuclear calculations that would improve our understanding of existing atomic data.

  19. New Precision Measurements of Deuteron Structure Function A(Q) at Low Momentum Transfer

    SciTech Connect

    Lee, Byungwuek

    2009-08-01

    Differences between previous measurements of low momentum transfer electron-deuteron elastic scattering prevent a clean determination of even the sign of the leading low momentum transfer relativistic corrections, or of the convergence of chiral perturbation theory. We have attempted to resolve this issue with a new high-precision measurement in Jefferson Lab Hall A. Elastic electron scattering was measured on targets of tantalum, carbon, hydrogen, and deuterium at beam energy of 685 MeV. The four-momentum transfer covered the range of 0.15 - 0.7 GeV. The experiment included a new beam calorimeter, to better calibrate the low beam currents used in the experiment, and new collimators to better define the spectrometer solid angles. We obtained cross sections of deuteron as ratios to hydrogen cross sections. A fit function of B(Q) world data is newly made and subtracted from cross sections to find values of A(Q).

  20. Simultaneous Enhancements of Conductivity and Stability for Anion Exchange Membranes (AEMs) through Precise Structure Design

    PubMed Central

    Ran, Jin; Wu, Liang; Wei, Bing; Chen, Yaoyao; Xu, Tongwen

    2014-01-01

    Polymeric materials as anion exchange membranes (AEMs) play an essential role in the field of energy and environment. The achievement of high performance AEMs by the precise manipulation of macromolecular architecture remains a daunting challenge. Herein, we firstly report a novel rod-coil graft copolymer AEM, possessing rigid hydrophobic main chains and soft hydrophilic graft chains. The low graft density, which can alleviate the adverse influences of ioinc graft chains on the main chains, was obtained by using the living polymerization technique. Consequently, the grafted ionic groups which result in the degradation of polymer backbone was decreased to a small degree. Moreover, the relatively long graft chains induced the nanophase separation between the hydrophobic polymer chains and hydrophilic graft chains, which creates a convinient pathway for high hydroxide ion mobility. Such an accurate molecular design simultaneously improves the hydroxide ion conductivity and alkaline stability as well as dimensional stability. PMID:25255843

  1. Transform methods for precision continuum and control models of flexible space structures

    NASA Technical Reports Server (NTRS)

    Lupi, Victor D.; Turner, James D.; Chun, Hon M.

    1991-01-01

    An open loop optimal control algorithm is developed for general flexible structures, based on Laplace transform methods. A distributed parameter model of the structure is first presented, followed by a derivation of the optimal control algorithm. The control inputs are expressed in terms of their Fourier series expansions, so that a numerical solution can be easily obtained. The algorithm deals directly with the transcendental transfer functions from control inputs to outputs of interest, and structural deformation penalties, as well as penalties on control effort, are included in the formulation. The algorithm is applied to several structures of increasing complexity to show its generality.

  2. Drone-acquired structure-from-motion photogrammetry for high-precision measurements of biomass in semi-arid rangelands

    NASA Astrophysics Data System (ADS)

    Cunliffe, Andrew; Brazier, Richard; Anderson, Karen

    2016-04-01

    Covering 40% of the terrestrial surface, dryland ecosystems have a distinct vegetation structure that is strongly linked to their function. Recent global modelling studies have indicated interannual variations in semiarid ecosystem biomass accounts for ca. 40%-60% of interannual variations in atmospheric carbon dioxide concentrations. Empirical evidence is needed to validate these model predictions; however, existing survey approaches cannot provide sufficiently precise data at landscape-scale extents to quantify this structure appropriately. Using a small unpiloted aerial system (UAS) to acquire aerial photographs and processing using structure-from-motion (SfM) photogrammetry, three dimensional models were produced quantifying the vegetation structure of semi-arid ecosystems at seven areas of interest (AOI). This approach yielded ultrafine (<1 cm2) spatial resolution canopy height models over landscape-scales (10 ha), which resolved individual grass tussocks just a few cm3 in volume. Canopy height cumulative distributions for each AOI illustrated ecologically-significant differences in ecosystem structure over a grass- to shrub-dominated vegetation transition. Strong coefficients of determination (r2 >0.64) supported prediction of aboveground biomass from canopy volume. Canopy volumes, modelled biomass and carbon stocks were sensitive to spatial changes in vegetation community structure. We demonstrate the use of an inexpensive UAS and SfM photogrammetry to produce ultrafine-scale biophysical data products. The high-precision of this approach affords sensitivity to subtle differences in the biotic structure (and therefore function) of heterogeneous ecosystems subject to rapid environmental change, and has exciting potential to revolutionise the study of spatial ecology in ecosystems with either spatially or temporally discontinuous canopy cover.

  3. Influence of standardization on the precision (reproducibility) of dental cast analysis with virtual 3-dimensional models.

    PubMed

    Hayashi, Kazuo; Chung, Onejune; Park, Seojung; Lee, Seung-Pyo; Sachdeva, Rohit C L; Mizoguchi, Itaru

    2015-03-01

    Virtual 3-dimensional (3D) models obtained by scanning of physical casts have become an alternative to conventional dental cast analysis in orthodontic treatment. If the precision (reproducibility) of virtual 3D model analysis can be further improved, digital orthodontics could be even more widely accepted. The purpose of this study was to clarify the influence of "standardization" of the target points for dental cast analysis using virtual 3D models. Physical plaster models were also measured to obtain additional information. Five sets of dental casts were used. The dental casts were scanned with R700 (3Shape, Copenhagen, Denmark) and REXCAN DS2 3D (Solutionix, Seoul, Korea) scanners. In this study, 3 system and software packages were used: SureSmile (OraMetrix, Richardson, Tex), Rapidform (Inus, Seoul, Korea), and I-DEAS (SDRC, Milford, Conn). Without standardization, the maximum differences were observed between the SureSmile software and the Rapidform software (0.39 mm ± 0.07). With standardization, the maximum differences were observed between the SureSmile software and measurements with a digital caliper (0.099 mm ± 0.01), and this difference was significantly greater (P <0.05) than the 2 other mean difference values. Furthermore, the results of this study showed that the mean differences "WITH" standardization were significantly lower than those "WITHOUT" standardization for all systems, software packages, or methods. The results showed that elimination of the influence of usability or habituation is important for improving the reproducibility of dental cast analysis. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  4. Precise equilibrium structure determination of hydrazoic acid (HN{sub 3}) by millimeter-wave spectroscopy

    SciTech Connect

    Amberger, Brent K.; Esselman, Brian J.; Woods, R. Claude; McMahon, Robert J.; Stanton, John F.

    2015-09-14

    The millimeter-wave spectrum of hydrazoic acid (HN{sub 3}) was analyzed in the frequency region of 235-450 GHz. Transitions from a total of 14 isotopologues were observed and fit using the A-reduced or S-reduced Hamiltonian. Coupled-cluster calculations were performed to obtain a theoretical geometry, as well as rotation-vibration interaction corrections. These calculated vibration-rotation correction terms were applied to the experimental rotational constants to obtain mixed theoretical/experimental equilibrium rotational constants (A{sub e}, B{sub e}, and C{sub e}). These equilibrium rotational constants were then used to obtain an equilibrium (R{sub e}) structure using a least-squares fitting routine. The R{sub e} structural parameters are consistent with a previously published R{sub s} structure, largely falling within the uncertainty limits of that R{sub s} structure. The present R{sub e} geometric parameters of HN{sub 3} are determined with exceptionally high accuracy, as a consequence of the large number of isotopologues measured experimentally and the sophisticated (coupled-cluster theoretical treatment (CCSD(T))/ANO2) of the vibration-rotation interactions. The R{sub e} structure exhibits remarkable agreement with the CCSD(T)/cc-pCV5Z predicted structure, validating both the accuracy of the ab initio method and the claimed uncertainties of the theoretical/experimental structure determination.

  5. Analysis of de-noising methods to improve the precision of the ILSF BPM electronic readout system

    NASA Astrophysics Data System (ADS)

    Shafiee, M.; Feghhi, S. A. H.; Rahighi, J.

    2016-12-01

    In order to have optimum operation and precise control system at particle accelerators, it is required to measure the beam position with the precision of sub-μm. We developed a BPM electronic readout system at Iranian Light Source Facility and it has been experimentally tested at ALBA accelerator facility. The results show the precision of 0.54 μm in beam position measurements. To improve the precision of this beam position monitoring system to sub-μm level, we have studied different de-noising methods such as principal component analysis, wavelet transforms, filtering by FIR, and direct averaging method. An evaluation of the noise reduction was given to testify the ability of these methods. The results show that the noise reduction based on Daubechies wavelet transform is better than other algorithms, and the method is suitable for signal noise reduction in beam position monitoring system.

  6. A novel method to precisely assemble loose nanofiber structures for regenerative medicine applications.

    PubMed

    Beachley, Vince; Katsanevakis, Eleni; Zhang, Ning; Wen, Xuejun

    2013-02-01

    Polymer nanofibers are favorable for tissue engineering scaffolds because of their high surface-to-volume ratio and biomimicry of the extracellular matrix. Random and uniaxially oriented polymer nanofibers are easily fabricated by conventional electrospinning techniques; however, control over fiber organization within nanofiber structures is limited when they are collected directly from an electrospinning jet. The regenerative medicine applications of electrospun scaffolds could be expanded by developing assembly methods that allow better control of fiber organization. Here, a novel technique is presented that utilizes parallel automated tracks to orient and collect nanofibers from an electrospinning jet. The stabilized fibers are then subsequently assembled into desirable structures. It is difficult to assemble complex structures directly from an electrospinning jet because of high electrical charge and velocities, so this technology adds an intermediate step where nanofibers are immobilized on automated tracks. The result is a continuous steady-state delivery of static stabilized nanofibers that provides a unique and promising platform for automated post processing into useful nanofiber structures. This technique also allows for an indefinite amount of time, as determined by design parameters, for fibers to dry or cool before they contact other nanofibers in the collection site, thus eliminating potential for fiber-to-fiber adhesions even with slow evaporating solvents or high-temperature melts. To demonstrate potential in regenerative medicine applications, several nanofiber structures were fabricated, including: 2D structures with well-controlled fiber density; 3D loosely assembled aligned nanofiber structures with good cell penetration properties; and, complex layer-by-layer 3D aligned fiber structures assembled by integration with post-processing techniques.

  7. Experimental Characterization of Hysteresis in a Revolute Joint for Precision Deployable Structures

    NASA Technical Reports Server (NTRS)

    Lake, Mark S.; Fung, Jimmy; Gloss, Kevin; Liechty, Derek S.

    1997-01-01

    Recent studies of the micro-dynamic behavior of a deployable telescope metering truss have identified instabilities in the equilibrium shape of the truss in response to low-energy dynamic loading. Analyses indicate that these micro-dynamic instabilities arise from stick-slip friction within the truss joints (e.g., hinges and latches). The present study characterizes the low-magnitude quasi-static load cycle response of the precision revolute joints incorporated in the deployable telescope metering truss, and specifically, the hysteretic response of these joints caused by stick-slip friction within the joint. Detailed descriptions are presented of the test setup and data reduction algorithms, including discussions of data-error sources and data-filtering techniques. Test results are presented from thirteen specimens, and the effects of joint preload and manufacturing tolerances are investigated. Using a simplified model of stick-slip friction, a relationship is made between joint load-cycle behavior and micro-dynamic dimensional instabilities in the deployable telescope metering truss.

  8. Analysis of Current Position Determination Accuracy in Natural Resources Canada Precise Point Positioning Service

    NASA Astrophysics Data System (ADS)

    Krzan, Grzegorz; Dawidowicz, Karol; Krzysztof, Świaţek

    2013-09-01

    Precise Point Positioning (PPP) is a technique used to determine highprecision position with a single GNSS receiver. Unlike DGPS or RTK, satellite observations conducted by the PPP technique are not differentiated, therefore they require that parameter models should be used in data processing, such as satellite clock and orbit corrections. Apart from explaining the theory of the PPP technique, this paper describes the available web-based online services used in the post-processing of observation results. The results obtained in the post-processing of satellite observations at three points, with different characteristics of environment conditions, using the CSRS-PPP service, will be presented as the results of the experiment. This study examines the effect of the duration of the measurement session on the results and compares the results obtained by working out observations made by the GPS system and the combined observations from GPS and GLONASS. It also presents the analysis of the position determination accuracy using one and two measurement frequencies

  9. Progress towards a precision measurement of the n=2 triplet P fine structure of atomic helium

    NASA Astrophysics Data System (ADS)

    Kato, K.; Fitzakerley, D. W.; George, M. C.; Vutha, A. C.; Storry, C. H.; Hessels, E. A.

    2016-05-01

    We report progress on the measurement of the J = 1 to J = 2 23 P fine-structure interval of atomic helium. The measurement uses a liquid-nitrogen-cooled DC discharge source of metastable helium and the atomic beam is laser cooled in the transverse directions. The atoms are excited to 23 P by a 1083-nm diode laser, and the fine-structure transition is driven by microwaves using the frequency-offset separated oscillatory fields technique. The transition is detected by further laser excitation to a Rydberg state, followed by Stark ionization. This work is supported by NSERC, CRC.

  10. A Revolute Joint With Linear Load-Displacement Response for Precision Deployable Structures

    NASA Technical Reports Server (NTRS)

    Lake, Mark S.; Warren, Peter A.; Peterson, Lee D.

    1996-01-01

    NASA Langley Research center is developing key structures and mechanisms technologies for micron-accuracy, in-space deployment of future space instruments. Achieving micron-accuracy deployment requires significant advancements in deployment mechanism design such as the revolute joint presented herein. The joint presented herein exhibits a load-cycling response that is essentially linear with less than two percent hysteresis, and the joint rotates with less than one in.-oz. of resistance. A prototype reflector metering truss incorporating the joint exhibits only a few microns of kinematic error under repeated deployment and impulse loading. No other mechanically deployable structure found in literature has been demonstrated to be this kinematically accurate.

  11. Regularized Generalized Structured Component Analysis

    ERIC Educational Resources Information Center

    Hwang, Heungsun

    2009-01-01

    Generalized structured component analysis (GSCA) has been proposed as a component-based approach to structural equation modeling. In practice, GSCA may suffer from multi-collinearity, i.e., high correlations among exogenous variables. GSCA has yet no remedy for this problem. Thus, a regularized extension of GSCA is proposed that integrates a ridge…

  12. Regularized Generalized Structured Component Analysis

    ERIC Educational Resources Information Center

    Hwang, Heungsun

    2009-01-01

    Generalized structured component analysis (GSCA) has been proposed as a component-based approach to structural equation modeling. In practice, GSCA may suffer from multi-collinearity, i.e., high correlations among exogenous variables. GSCA has yet no remedy for this problem. Thus, a regularized extension of GSCA is proposed that integrates a ridge…

  13. The Precision Medicine Nation.

    PubMed

    Sabatello, Maya; Appelbaum, Paul S

    2017-07-01

    The United States' ambitious Precision Medicine Initiative proposes to accelerate exponentially the adoption of precision medicine, an approach to health care that tailors disease diagnosis, treatment, and prevention to individual variability in genes, environment, and lifestyle. It aims to achieve this by creating a cohort of volunteers for precision medicine research, accelerating biomedical research innovation, and adopting policies geared toward patients' empowerment. As strategies to implement the PMI are formulated, critical consideration of the initiative's ethical and sociopolitical dimensions is needed. Drawing on scholarship of nationalism and democracy, we discuss the PMI's construction of what we term "genomic citizenship"; the possible normative obligations arising therefrom; and the ethical, legal, and social challenges that will ensue. Although the PMI is a work in progress, discussion of the existing and emerging issues can facilitate the development of policies, structures, and procedures that can maximize the initiative's ability to produce equitable and socially sensitive outcomes. Our analysis can also be applied to other population-based, precision medicine research programs. © 2017 The Hastings Center.

  14. Sizing-up finite fluorescent particles with nanometer-scale precision by convolution and correlation image analysis.

    PubMed

    Gennerich, Arne; Schild, Detlev

    2005-05-01

    Determining the positions, shapes and sizes of finite living particles such as bacteria, mitochondria or vesicles is of interest in many biological processes. In fluorescence microscopy, algorithms that can simultaneously localize such particles as a function of time and determine the parameters of their shapes and sizes at the nanometer scale are not yet available. Here we develop two such algorithms based on convolution and correlation image analysis that take into account the position, orientation, shape and size of the object being tracked, and we compare the precision of the two algorithms using computer simulations. We show that the precision of both algorithms strongly depends on the object's size. In cases where the diameter of the object is larger than about four to five times the beam waist radius, the convolution algorithm gives a better precision than the correlation algorithm (it leads to more precise parameters), while for smaller object diameters, the correlation algorithm gives superior precision. We apply the convolution algorithm to sequences of confocal laser scanning micrographs of immobile Escherichia coli bacteria, and show that the centroid, the front end, the rear end, the left border and the right border of a bacterium can be determined with a signal-to-noise-dependent precision down to approximately 5 nm.

  15. QCD Precision Measurements and Structure Function Extraction at a High Statistics, High Energy Neutrino Scattering Experiment: NuSOnG

    SciTech Connect

    Adams, T.; Batra, P.; Bugel, Leonard G.; Camilleri, Leslie Loris; Conrad, Janet Marie; de Gouvea, A.; Fisher, Peter H.; Formaggio, Joseph Angelo; Jenkins, J.; Karagiorgi, Georgia S.; Kobilarcik, T.R.; /Fermilab /Texas U.

    2009-06-01

    We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDFs). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parameterized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of 'Beyond the Standard Model' physics.

  16. Crump Geyser Exploration and Drilling Project. High Precision Geophysics and Detailed Structural Exploration and Slim Well Drilling

    SciTech Connect

    Fairbank, Brian D.; Smith, Nicole

    2015-06-10

    The Crump Geyser Exploration and Drilling Project – High Precision Geophysics and Detailed Structural Exploration and Slim Well Drilling ran from January 29, 2010 to September 30, 2013. During Phase 1 of the project, collection of all geophysical surveys was completed as outlined in the Statement of Project Objectives. In addition, a 5000-foot full sized exploration well was drilled by Ormat, and preexisting drilling data was discovered for multiple temperature gradient wells within the project area. Three dimensional modeling and interpretation of results from the geophysical surveys and drilling data gave confidence to move to the project into Phase 2 drilling. Geological and geophysical survey interpretations combined with existing downhole temperature data provided an ideal target for the first slim-hole drilled as the first task in Phase 2. Slim-hole 35-34 was drilled in September 2011 and tested temperature, lithology, and permeability along the primary range-bounding fault zone near its intersection with buried northwest-trending faults that have been identified using geophysical methods. Following analysis of the results of the first slim-hole 35-34, the second slim hole was not drilled and subsequent project tasks, including flowing differential self-potential (FDSP) surveys that were designed to detail the affect of production and injection on water flow in the shallow aquifer, were not completed. NGP sold the Crump project to Ormat in August 2014, afterwards, there was insufficient time and interest from Ormat available to complete the project objectives. NGP was unable to continue managing the award for a project they did not own due to liability issues and Novation of the award was not a viable option due to federal award timelines. NGP submitted a request to mutually terminate the award on February 18, 2015. The results of all of the technical surveys and drilling are included in this report. Fault interpretations from surface geology, aeromag

  17. Boundary elements for structural analysis

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The intent here is to discuss the status of the boundary element method (BEM) for structural analysis, both in terms of the present and anticipated capabilities of the method and in terms of the incorporation of the method in the design/analysis process, particularly for gas turbine engine components.

  18. 3D X-rays application for precision measurement of the cell structure of extruded polystyrene

    NASA Astrophysics Data System (ADS)

    Lim, J. Y.; Kim, K. Y.; Shin, H. S.; Yeom, S.; Lee, S. E.

    2015-12-01

    While the thermal performance of existing insulation materials have been determined by blister gases, the thermal performance of future insulation materials will be dependent on the cell size and independent foam content as we use eco-friendly blister gases with a higher thermal conductivity. However, with the current technology we are only able to guess the whole cell size and independent foam content through SEM applied 2D fragmentary scanning but are still far from the level of accurate cell structure data extraction. Under this situation, we utilized X-ray CT scanned 3D images to identify and shape the cell structure and proposed a method of inferring the whole distribution and independent foam content as accurately as possible. According to X-ray CT scanning images and SEM images, the shape was similar but according to tracer applied CT scanning images, the cell size distribution was 380∼400 pm within the range of the general insulation diameter distribution which had the highest reliability. As for extrusion foaming polystyrene, we need additional image processing to identify the independent foam content as its density is too low. So, it is recommended to raise the 3D cell structure completeness of XPS by improving the scanning accuracy.

  19. High precision earthquake locations reveal seismogenic structure beneath Mammoth Mountain, California

    USGS Publications Warehouse

    Prejean, Stephanie G.; Stork, Anna; Ellsworth, William L.; Hill, David; Julian, Bruce R.

    2003-01-01

    In 1989, an unusual earthquake swarm occurred beneath Mammoth Mountain that was probably associated with magmatic intrusion. To improve our understanding of this swarm, we relocated Mammoth Mountain earthquakes using a double difference algorithm. Relocated hypocenters reveal that most earthquakes occurred on two structures, a near-vertical plane at 7–9 km depth that has been interpreted as an intruding dike, and a circular ring-like structure at ∼5.5 km depth, above the northern end of the inferred dike. Earthquakes on this newly discovered ring structure form a conical section that dips outward away from the aseismic interior. Fault-plane solutions indicate that in 1989 the seismicity ring was slipping as a ring-normal fault as the center of the mountain rose with respect to the surrounding crust. Seismicity migrated around the ring, away from the underlying dike at a rate of ∼0.4 km/month, suggesting that fluid movement triggered seismicity on the ring fault.

  20. Sensitivity Analysis for Characterizing the Accuracy and Precision of JEM/SMILES Mesospheric O3

    NASA Astrophysics Data System (ADS)

    Esmaeili Mahani, M.; Baron, P.; Kasai, Y.; Murata, I.; Kasaba, Y.

    2011-12-01

    The main purpose of this study is to evaluate the Superconducting sub-Millimeter Limb Emission Sounder (SMILES) measurements of mesospheric ozone, O3. As the first step, the error due to the impact of Mesospheric Temperature Inversions (MTIs) on ozone retrieval has been determined. The impacts of other parameters such as pressure variability, solar events, and etc. on mesospheric O3 will also be investigated. Ozone, is known to be important due to the stratospheric O3 layer protection of life on Earth by absorbing harmful UV radiations. However, O3 chemistry can be studied purely in the mesosphere without distraction of heterogeneous situation and dynamical variations due to the short lifetime of O3 in this region. Mesospheric ozone is produced by the photo-dissociation of O2 and the subsequent reaction of O with O2. Diurnal and semi-diurnal variations of mesospheric ozone are associated with variations in solar activity. The amplitude of the diurnal variation increases from a few percent at an altitude of 50 km, to about 80 percent at 70 km. Although despite the apparent simplicity of this situation, significant disagreements exist between the predictions from the existing models and observations, which need to be resolved. SMILES is a highly sensitive radiometer with a few to several tens percent of precision from upper troposphere to the mesosphere. SMILES was developed by the Japanese Aerospace eXploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT) located at the Japanese Experiment Module (JEM) on the International Space Station (ISS). SMILES has successfully measured the vertical distributions and the diurnal variations of various atmospheric species in the latitude range of 38S to 65N from October 2009 to April 2010. A sensitivity analysis is being conducted to investigate the expected precision and accuracy of the mesospheric O3 profiles (from 50 to 90 km height) due to the impact of Mesospheric Temperature

  1. Trueness, Precision, and Detectability for Sampling and Analysis of Organic Species in Airborne Particulate Matter

    EPA Science Inventory

    Recovery. precision, limits of detection and quantitation, blank levels, calibration linearity, and agreement with certified reference materials were determined for two classes of organic components of airborne particulate matter, polycyclic aromatic hydrocarbons and hopanes usin...

  2. Fast-Time Analysis Support for the Terminal Area Precision Scheduling and Spacing (TAPSS) Simulation

    NASA Technical Reports Server (NTRS)

    Mulfinger, Daniel

    2011-01-01

    This poster describes research conducted using the Stochastic Terminal Area Simulation Software to determine spacing buffers for the Terminal Area Precision Scheduling and Spacing human-in-the-loop simulation.

  3. Probabilistic Structural Analysis Theory Development

    NASA Technical Reports Server (NTRS)

    Burnside, O. H.

    1985-01-01

    The objective of the Probabilistic Structural Analysis Methods (PSAM) project is to develop analysis techniques and computer programs for predicting the probabilistic response of critical structural components for current and future space propulsion systems. This technology will play a central role in establishing system performance and durability. The first year's technical activity is concentrating on probabilistic finite element formulation strategy and code development. Work is also in progress to survey critical materials and space shuttle mian engine components. The probabilistic finite element computer program NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) is being developed. The final probabilistic code will have, in the general case, the capability of performing nonlinear dynamic of stochastic structures. It is the goal of the approximate methods effort to increase problem solving efficiency relative to finite element methods by using energy methods to generate trial solutions which satisfy the structural boundary conditions. These approximate methods will be less computer intensive relative to the finite element approach.

  4. Probabilistic Structural Analysis Theory Development

    NASA Technical Reports Server (NTRS)

    Burnside, O. H.

    1985-01-01

    The objective of the Probabilistic Structural Analysis Methods (PSAM) project is to develop analysis techniques and computer programs for predicting the probabilistic response of critical structural components for current and future space propulsion systems. This technology will play a central role in establishing system performance and durability. The first year's technical activity is concentrating on probabilistic finite element formulation strategy and code development. Work is also in progress to survey critical materials and space shuttle mian engine components. The probabilistic finite element computer program NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) is being developed. The final probabilistic code will have, in the general case, the capability of performing nonlinear dynamic of stochastic structures. It is the goal of the approximate methods effort to increase problem solving efficiency relative to finite element methods by using energy methods to generate trial solutions which satisfy the structural boundary conditions. These approximate methods will be less computer intensive relative to the finite element approach.

  5. Comparison and Analysis of BeiDou Satellite Single-system Precise Orbit Determination

    NASA Astrophysics Data System (ADS)

    Liu, W. P.; Hao, J. M.; Deng, K.; Chen, Y. L.

    2016-09-01

    The method of double-difference dynamic precise orbit determination for BeiDou satellites by using both carrier phase and smoothed pseudo-range is presented. The data processing flows of zero-difference and double-difference dynamic precise orbit determination for BeiDou satellites are presented. And the two methods are analyzed. The precision of two methods is compared based on the real data. The results show that in the condition of stations layout and by using the two methods, the three-dimension precision of GEO (Geostationary Earth Orbit Satellite) can reach about 1 m, and those of IGSO (Inclined Geosynchronous Earth Orbit Satellite) and MEO (Medium Earth Orbit Satellite) can be better than 0.5 m. And the radial precision of the three kinds of orbit satellites can be all better than 10 cm. Compared with the zero-difference dynamic method, the orbit precision of GEO is better with the double-difference dynamic method, and that of IGSO is comparable, but that of MEO is worse.

  6. Transform Methods for Precision Nonlinear Wave Models of Flexible space Structures

    DTIC Science & Technology

    1990-08-20

    functional analysis. A later work by Tzafestas (1970) derived the I necessary conditions for optimality from a variational calculus approach. A...the classical variational calculus approach to distributed systems. Note that 106 I’ the cost functional has infinite time horizon. This corresponds...Nightingale, j.M., 1970, "Optimal Distributed Parameter Control Using Classical Variational Calculus ," Int. J. Control, V12, #4, pp. 593-608. Wang, P.C

  7. Precision growth index using the clustering of cosmic structures and growth data

    SciTech Connect

    Pouri, Athina; Basilakos, Spyros; Plionis, Manolis E-mail: svasil@academyofathens.gr

    2014-08-01

    We use the clustering properties of Luminous Red Galaxies (LRGs) and the growth rate data provided by the various galaxy surveys in order to constrain the growth index γ) of the linear matter fluctuations. We perform a standard χ{sup 2}-minimization procedure between theoretical expectations and data, followed by a joint likelihood analysis and we find a value of γ=0.56± 0.05, perfectly consistent with the expectations of the ΛCDM model, and Ω{sub m0} =0.29± 0.01, in very good agreement with the latest Planck results. Our analysis provides significantly more stringent growth index constraints with respect to previous studies, as indicated by the fact that the corresponding uncertainty is only ∼ 0.09 γ. Finally, allowing γ to vary with redshift in two manners (Taylor expansion around z=0, and Taylor expansion around the scale factor), we find that the combined statistical analysis between our clustering and literature growth data alleviates the degeneracy and obtain more stringent constraints with respect to other recent studies.

  8. High-precision mass spectrometric analysis using stable isotopes in studies of children.

    PubMed

    Schierbeek, Henk; van den Akker, Chris H P; Fay, Laurent B; van Goudoever, Johannes B

    2012-01-01

    The use of stable isotopes combined with mass spectrometry (MS) provides insight into metabolic processes within the body. Herein, an overview on the relevance of stable isotope methodology in pediatric research is presented. Applications for the use of stable isotopes with MS cover carbohydrate, fat, and amino acid metabolism as well as body composition, energy expenditure, and the synthesis of specific peptides and proteins, such as glutathione and albumin. The main focus of these studies is on the interactions between nutrients and the endogenous metabolism within the body and how these factors affect the health of a growing infant. Considering that the early imprinting of metabolic processes hugely impacts metabolism (and thus functional outcome) later in life, research in this area is important and is advancing rapidly. The major fluxes on a metabolic level are the synthesis and breakdown rates. They can be quantified using kinetic tracer analysis and mathematical modeling. Organic MS and isotope ratio mass spectrometry (IRMS) are the two most mature techniques for the isotopic analysis of compounds. Introduction of the samples is usually done by coupling gas chromatography (GC) to either IRMS or MS because it is the most robust technique for specific isotopic analysis of volatile compounds. In addition, liquid chromatography (LC) is now being used more often as a tool for sample introduction of both volatile and non-volatile compounds into IRMS or MS for (13)C isotopic analyses at natural abundances and for (13)C-labeled enriched compounds. The availability of samples is often limited in pediatric patients. Therefore, sample size restriction is important when developing new methods. Also, the availability of stable isotope-labeled substrates is necessary for measurements of the kinetics and concentrations in metabolic studies, which can be a limiting factor. During the last decade, the availability of these substrates has increased. Furthermore, improvements

  9. The Precision Measurement of the Neutron Spin Structure Function Using Polarized HE-3 Target

    SciTech Connect

    Wang, X

    2004-01-05

    Using a 48.6 GeV polarized electron beam scattering off a polarized {sup 3}He target at Stanford Linear Accelerator Centre (SLAC), they measured the neutron spin structure function g{sub 1}{sup n} over kinematic(x) ranging 0.014 < x <0.7 and 1 < Q{sup 2} < 17GeV{sup 2}. The measurement gave the integral result over the neutron spin structure function {integral}{sub 0.014}{sup 0.7} g{sub 1}{sup n}(x)dx = -0.036 {+-} 0.004(stat) {+-} 0.005(syst) at an average Q{sup 2} = 5GeV{sup 2}. Along with the proton results from SLAC E143 experiment (0.03 < x) and SMC experiment (0.014 < x < 0.03), they find the Bjorken sum rule appears to be largely saturated by the data integrated down to x of 0.014. However, they observe relatively large values for g{sub 1}{sup n} at low x. The result calls into question the usual methods (Regge theory) for extrapolating to x = 0 to find the full neutron integral {integral}{sub 0}{sup t} g{sub 1}{sup n}(x) dx, needed for testing the Quark-Parton Model (QMP).

  10. Design of a precise and stable composite telescope structure for the Ultraviolet Coronagraph Spectrometer (UVCS)

    NASA Technical Reports Server (NTRS)

    Kilpatrick, Mark C.; Girard, Joseph D.; Dodson, Kelly J.

    1992-01-01

    The Ultraviolet Coronagraph Spectrometer is a state of the art instrument which will be flown aboard the ESA SOHO spacecraft in 1995. A major objective of the SOHO is to investigate the solar corona and the solar wind by measuring parameters of the plasma, both in the source and acceleration regions, and in interplanetary space. The UVCS will provide ultraviolet spectroscopic diagnostics of temperature, density, and outflow velocity for coronal ions located between the base of the solar corona and 10 solar radii. The requirements placed on the UVCS telescope structure by the science and the spacecraft are challenging. Obtaining this scientific data requires that the telescope maintain pointing stability within a few arc-seconds in a transient thermal environment and an imaging stability within a few microns. Strict mass allowances permit only 22 kg for the 2.5 meter long telescope structure out of a total instrument allotment of 124 kg. The instrument is required to have a high minimum natural frequency of 70 Hertz and withstand launch inertia loads in excess of 18-G's while kinematically supported.

  11. High-precision electronic structure studies of thermoelectrics: Bi_2Te_3

    NASA Astrophysics Data System (ADS)

    Kim, Miyoung; Freeman, A. J.; Geller, C. B.

    2004-03-01

    The heavy-atom, narrow-bandgap semiconductor Bi_2Te3 is of centralcommercial importance for thermoelectric cooling. Detailed ab initio screened exchange(R. Asahi, W. Mannstadt, A.J. Freeman, Phys. Rev. B, 59), 7486 (1999) (sX-LDA) electronic structure calculations have been performed for Bi_2Te3 within the full-potential linearized augmented plane wave (FLAPW)footnote Wimmer, Krakauer, Weinert, Freeman, Phys. Rev. B 24, 864(1981) method, accounting for spin-orbit coupling self-consistently. An indirect bandgap of 0.155 eV is found for a conduction band (CB) minimum on the mirror plane containing the trigonal and bisectric axes, thus confirming the experimental(H. Köhler, Phys. Status. Solidi, 73), 95 (1976); 74, 591 (1976) and earlier theoretical(S. Youn, A.J. Freeman, Phys. Rev. B, 63), 085112 (2001) observations of sixfold-degenerate CB and VB extrema in doped Bi_2Te_3. The predicted sX-LDA bandgap value is <5% of the zero temperature-extrapolated experimental value(B.M. Golts'man, et.al., Thermoelectric Semiconductor Materials Based on Bi_2Te_3, English trans., US Nat. Tech. Info Center (1973).) (0.162 eV). These values compare with a predicted LDA bandgap^3 (on the mirror plane) of 0.045 eV. The carrier density dependence of the effective mass tensor and the Seebeck coefficient are explored using our accurate quasiparticle band structure.

  12. Position estimation for timing belt drives of precision machinery using structured neural networks

    NASA Astrophysics Data System (ADS)

    Kilic, Ergin; Dogruer, Can Ulas; Dolen, Melik; Koku, Ahmet Bugra

    2012-05-01

    This paper focuses on a viable position estimation scheme for timing-belt drives using artificial neural networks. In this study, the position of a carriage (load) is calculated via a structured neural network topology accepting input from a position sensor on the actuator side of the timing belt. The paper presents a detailed discussion on the source of transmission errors. The characteristics of the error in different operation regimes are exploited to construct different network topologies. That is, a relevant neural network model is developed by the sketchy guidance of a priori knowledge on the process. The resulting structured neural network is shown to estimate the error of the carriage quite accurately whereas generic recurrent neural networks fail to capture the dynamics of the system under investigation altogether. Extensive testing demonstrates the effectiveness of proposed method when the drive system is not subjected to external loads while the operating conditions such as ambient temperature and belt tensions do not deviate from the experimental conditions.

  13. Comparative analysis of earthquakes data recorded by the innovative Precision Laser Inclinometer instruments and the classic Hydrostatic Level System

    NASA Astrophysics Data System (ADS)

    Azaryan, N.; Batusov, V.; Budagov, J.; Glagolev, V.; Lyablin, M.; Trubnikov, G.; Shirkov, G.; Gayde, J.-Ch.; Di Girolamo, B.; Herty, A.; Mainaud Durand, H.; Mergelkuhl, D.; Rude, V.

    2017-05-01

    The Hydrostatic Level System (HLS) data and the Precision Laser Inclinometer (PLI) instruments data have been comparatively analyzed in the event of surface angular oscillations induced by earthquakes. The comparative data analysis has shown an agreement on the arrival and stop time of earthquakes. The data have been analyzed within the instruments sensitivity ranges having an overlap in frequency intervals.

  14. High-Precision Selenium Isotope Analysis by Hydride Generation MC-ICP-MS: Environmental Applications

    NASA Astrophysics Data System (ADS)

    Schmidberger, S.; Simonetti, A.; Gariépy, C.

    2003-04-01

    The global cycle and the natural isotopic variation of Se in the lithosphere, biosphere, hydrosphere and atmosphere are currently little constrained. The study of Se isotope systematics by negative thermal ionization mass spectrometry (NTIMS) has documented large Se isotope variations up to 15 ppm in various natural samples (δ80Se/76Se; Johnson et al., 1999), indicating its important potential as a tracer in geological and biological processes. Recently, Se isotope measurements on sulfide deposits from hydrothermal systems were obtained using a Micromass IsoProbe multicollector inductively coupled plasma mass spectrometer coupled to a hydride generator (Rouxel et al. 2002). This technique allows for high-precision Se isotope analysis on small sample sizes (<= 100 ng), and thus is a prerequisite for precise Se isotope measurements in low abundance samples such as precipitations, freshwaters and atmospheric aerosols (1 ppb or less). We have developed a 74-82Se double spike technique, which corrects for instrumental mass fractionation during both isotopic analysis and chemical processing. During double spike calibration, mass discrimination was monitored using a Germanium Specpuretextregistered standard (25 ppb). The isotopic composition of the Ge standard was accurately determined using a 10 ppb solution of the isotopic Gallium standard SRM 994. Repeated measurements (n=8) of the Ge standard yielded an external reproducibility of 0.13 ppm and a 74Ge/72Ge ratio of 1.32987. Instrumental mass bias evaluated with the Ge standard was essentially invariant over a three-month period. Our results yield an external reproducibility of 0.4 ppm (80Se/76Se) for a 100 ppb solution of the Se standard SRM 3149 (˜100 ng of total Se consumed). This ongoing study focuses on determining the Se isotopic compositions of precipitations and aerosol samples from remote and urban areas in northeastern North America. The preliminary results for precipitation samples (˜100 to 300 ml of rain

  15. Uncovering precision phenotype-biomarker associations in traumatic brain injury using topological data analysis

    PubMed Central

    Nielson, Jessica L.; Cooper, Shelly R.; Sorani, Marco D.; Inoue, Tomoo; Yuh, Esther L.; Mukherjee, Pratik; Petrossian, Tanya C.; Lum, Pek Y.; Lingsma, Hester F.; Gordon, Wayne A.; Okonkwo, David O.; Manley, Geoffrey T.

    2017-01-01

    Background Traumatic brain injury (TBI) is a complex disorder that is traditionally stratified based on clinical signs and symptoms. Recent imaging and molecular biomarker innovations provide unprecedented opportunities for improved TBI precision medicine, incorporating patho-anatomical and molecular mechanisms. Complete integration of these diverse data for TBI diagnosis and patient stratification remains an unmet challenge. Methods and findings The Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) Pilot multicenter study enrolled 586 acute TBI patients and collected diverse common data elements (TBI-CDEs) across the study population, including imaging, genetics, and clinical outcomes. We then applied topology-based data-driven discovery to identify natural subgroups of patients, based on the TBI-CDEs collected. Our hypothesis was two-fold: 1) A machine learning tool known as topological data analysis (TDA) would reveal data-driven patterns in patient outcomes to identify candidate biomarkers of recovery, and 2) TDA-identified biomarkers would significantly predict patient outcome recovery after TBI using more traditional methods of univariate statistical tests. TDA algorithms organized and mapped the data of TBI patients in multidimensional space, identifying a subset of mild TBI patients with a specific multivariate phenotype associated with unfavorable outcome at 3 and 6 months after injury. Further analyses revealed that this patient subset had high rates of post-traumatic stress disorder (PTSD), and enrichment in several distinct genetic polymorphisms associated with cellular responses to stress and DNA damage (PARP1), and in striatal dopamine processing (ANKK1, COMT, DRD2). Conclusions TDA identified a unique diagnostic subgroup of patients with unfavorable outcome after mild TBI that were significantly predicted by the presence of specific genetic polymorphisms. Machine learning methods such as TDA may provide a robust

  16. High-precision isotopic analysis of palmitoylcarnitine by liquid chromatography/electrospray ionization ion-trap tandem mass spectrometry.

    PubMed

    Guo, ZengKui; Yarasheski, Kevin; Jensen, Michael D

    2006-01-01

    Single quadrupole gas chromatography/mass spectrometry (GC/MS) has been widely used for isotopic analysis in metabolic investigations using stable isotopes as tracers. However, its inherent shortcomings prohibit it from broader use, including low isotopic precision and the need for chemical derivatization of the analyte. In order to improve isotopic detection power, liquid chromatography/electrospray ionization ion-trap tandem mass spectrometry (LC/ESI-itMS2) has been evaluated for its isotopic precision and chemical sensitivity for the analysis of [13C]palmitoylcarnitine. Over the enrichment range of 0.4-10 MPE (molar % excess), the isotopic response of LC/ESI-itMS2 to [13C]palmitoylcarnitine was linear (r = 1.00) and the average isotopic precision (standard deviation, SD) was 0.11 MPE with an average coefficient of variation (CV) of 5.6%. At the lower end of isotopic enrichments (0.4-0.9 MPE), the isotopic precision was 0.05 MPE (CV = 8%). Routine analysis of rat skeletal muscle [13C4]palmitoylcarnitine demonstrated an isotopic precision of 0.03 MPE for gastrocnemius (n = 16) and of 0.02 MPE for tibialis anterior (n = 16). The high precision enabled the detection of a small (0.08 MPE) but significant (P = 0.01) difference in [13C4]palmitoylcarnitine enrichments between the two muscles, 0.51 MPE (CV = 5.8%) and 0.43 MPE (CV = 4.6%), respectively. Therefore, the system demonstrated an isotopic lower detection limit (LDL) of < or =0.1 MPE (2 x SD) that has been impossible previously with other organic mass spectrometry instruments. LC/ESI-itMS2 systems have the potential to advance metabolic investigations using stable isotopes to a new level by significantly increasing the isotopic solving power.

  17. Experimental verification of distributed piezoelectric actuators for use in precision space structures

    NASA Technical Reports Server (NTRS)

    Crawley, E. F.; De Luis, J.

    1986-01-01

    An analytic model for structures with distributed piezoelectric actuators is experimentally verified for the cases of both surface-bonded and embedded actuators. A technique for the selection of such piezoelectric actuators' location has been developed, and is noted to indicate that segmented actuators are always more effective than continuous ones, since the output of each can be individually controlled. Manufacturing techniques for the bonding or embedding of segmented piezoelectric actuators are also developed which allow independent electrical contact to be made with each actuator. Static tests have been conducted to determine how the elastic properties of the composite are affected by the presence of an embedded actuator, for the case of glass/epoxy laminates.

  18. High-precision Penning-trap mass measurements of heavy xenon isotopes for nuclear structure studies

    SciTech Connect

    Neidherr, D.; Cakirli, R. B.; Audi, G.; Lunney, D.; Minaya-Ramirez, E.; Naimi, S.; Beck, D.; Herfurth, F.; Blaum, K.; Boehm, Ch.; George, S.; Breitenfeldt, M.; Rosenbusch, M.; Schweikhard, L.; Casten, R. F.; Herlert, A.; Kowalska, M.; Kellerbauer, A.; Schwarz, S.

    2009-10-15

    With the double Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN the masses of the neutron-rich isotopes {sup 136-146}Xe were measured with a relative uncertainty of the order of 10{sup -8} to 10{sup -7}. In particular, the masses of {sup 144-146}Xe were measured for the first time. These new mass values allow one to extend calculations of the mass surface in this region. Proton-Neutron interaction strength, obtained from double differences of binding energies, relate to subtle structural effects, such as the onset of octupole correlations, the growth of collectivity, and its relation to the underlying shell model levels. In addition, they provide a test of density functional calculations.

  19. Controlling Structural Transitions in AuAg Nanoparticles through Precise Compositional Design.

    PubMed

    Gould, Anna L; Rossi, Kevin; Catlow, C Richard A; Baletto, Francesca; Logsdail, Andrew J

    2016-11-03

    We present a study of the transitional pathways between high-symmetry structural motifs for AgAu nanoparticles, with a specific focus on controlling the energetic barriers through chemical design. We show that the barriers can be altered by careful control of the elemental composition and chemical arrangement, with core@shell and vertex-decorated arrangements being specifically influential on the barrier heights. We also highlight the complexity of the potential and free energy landscapes for systems where there are low-symmetry geometric motifs that are energetically competitive to the high-symmetry arrangements. In particular, we highlight that some core@shell arrangements preferentially transition through multistep restructuring of low-symmetry truncated octahedra and rosette-icosahedra, instead of via the more straightforward square-diamond transformations, due to lower energy barriers and competitive energetic minima. Our results have promising implications for the continuing efforts in bespoke nanoparticle design for catalytic and plasmonic applications.

  20. Precision Measurement of the Proton and Deuteron Spin Structure Functions g2

    SciTech Connect

    Rock, Stephen E.

    2003-02-27

    We measured the spin structure functions g{sub 2}{sup p} and g{sub 2}{sup d} in the range 0.02 {le} x {le} 0.8 and 0.7 {le} Q{sup 2} {le} 20 GeV{sup 2} by scattering 29.1 and 32.3 GeV longitudinally polarized electrons from transversely polarized NH{sub 3} and {sup 6}LiD targets. g{sub 2} approximately follows the twist-2 Wandzura-Wilczek calculation. The twist-3 reduced matrix elements d{sub 2}{sup p} and d{sub 2}{sup m} are less than two standard deviations from zero. The data are inconsistent with the Burkhardt-Cottingham sum rule if there is no pathological behavior as x {yields} 0. The Efremov-Leader-Teryaev integral is consistent with zero.

  1. Improved cryoEM-Guided Iterative Molecular Dynamics–Rosetta Protein Structure Refinement Protocol for High Precision Protein Structure Prediction

    PubMed Central

    2016-01-01

    Many excellent methods exist that incorporate cryo-electron microscopy (cryoEM) data to constrain computational protein structure prediction and refinement. Previously, it was shown that iteration of two such orthogonal sampling and scoring methods – Rosetta and molecular dynamics (MD) simulations – facilitated exploration of conformational space in principle. Here, we go beyond a proof-of-concept study and address significant remaining limitations of the iterative MD–Rosetta protein structure refinement protocol. Specifically, all parts of the iterative refinement protocol are now guided by medium-resolution cryoEM density maps, and previous knowledge about the native structure of the protein is no longer necessary. Models are identified solely based on score or simulation time. All four benchmark proteins showed substantial improvement through three rounds of the iterative refinement protocol. The best-scoring final models of two proteins had sub-Ångstrom RMSD to the native structure over residues in secondary structure elements. Molecular dynamics was most efficient in refining secondary structure elements and was thus highly complementary to the Rosetta refinement which is most powerful in refining side chains and loop regions. PMID:25883538

  2. Improved cryoEM-Guided Iterative Molecular Dynamics--Rosetta Protein Structure Refinement Protocol for High Precision Protein Structure Prediction.

    PubMed

    Lindert, Steffen; McCammon, J Andrew

    2015-03-10

    Many excellent methods exist that incorporate cryo-electron microscopy (cryoEM) data to constrain computational protein structure prediction and refinement. Previously, it was shown that iteration of two such orthogonal sampling and scoring methods – Rosetta and molecular dynamics (MD) simulations – facilitated exploration of conformational space in principle. Here, we go beyond a proof-of-concept study and address significant remaining limitations of the iterative MD–Rosetta protein structure refinement protocol. Specifically, all parts of the iterative refinement protocol are now guided by medium-resolution cryoEM density maps, and previous knowledge about the native structure of the protein is no longer necessary. Models are identified solely based on score or simulation time. All four benchmark proteins showed substantial improvement through three rounds of the iterative refinement protocol. The best-scoring final models of two proteins had sub-Ångstrom RMSD to the native structure over residues in secondary structure elements. Molecular dynamics was most efficient in refining secondary structure elements and was thus highly complementary to the Rosetta refinement which is most powerful in refining side chains and loop regions.

  3. Which method for a quick and precise modal analysis? Application to coupled polymer waveguides

    NASA Astrophysics Data System (ADS)

    Bellini, Bob; Larchanche, Jean-Francois; Jin, Guanghai; Harari, Joseph; Vilcot, Jean-Pierre; Decoster, Didier J.

    1999-12-01

    We present a study for an easy-going and fast modal analysis. We tackle the problem with three different approaches: the first one adopts a finalist viewpoint and is based on the 3D finite Difference Beam Propagation Method along imaginary axis. The second one is the numerical analysis' classical finite element method, applied to H. The third one consists in amounting to slab waveguides for which there are analytical solutions. We emphasize on the distinct natures of errors and, as an illustration, we study one optical ridge waveguide and one buried waveguide, made up with polymers. The methods are computed on 200-MHz PC and we discuss calculation time and accuracy. Eventually, through the conception of a candid coupler, we demonstrate what it costs to choose the wrong way, and in view of typical parameters of these structure, which is the most suitable method.

  4. A Precision Measurement of the Spin Structure of the Proton at SLAC

    SciTech Connect

    Erbacher, Robin D

    1999-09-22

    E143 at SLAC Endstation A performed deep-inelastic scattering measurements of polarized electrons from polarized protons and deuterons within cryogenic {sup 15}NH{sub 3} and {sup 15}ND{sub 3}, respectively. Data were taken at incident energies of 29.1, 16.2 and 9.7 GeV, and covered the kinematical range x > 0:03 and 0:3 < Q{sup 2} < 12 (GeV/c){sup 2}. The scattered electrons were detected by two spectrometers at angles of 4.5{sup o} and 7.0{sup o}. From these data, the spin-dependent structure functions g{sub 1}{sup p}(x; Q{sup 2}) and g{sub 1}{sup d}(x; Q{sup 2}) were determined. This dissertation describes the experiment, with emphasis on the results on the proton spin structure. The integral of g{sub 1} over the range 0 < x < 1 was found to be {Gamma}{sub 1}{sup p} = 0.130 {+-} 0.003 {+-} 0.008 for the proton and {Gamma}{sub 1}{sup d} = 0.044 {+-} 0.003 {+-} 0.004 for the deuteron. Both values are in agreement with world data, and violate the Ellis-Jaffe sum rule by more than 3 standard deviations. The neutron structure function was obtained by combining proton and deuteron results, giving {Gamma}{sub 1}{sup n} = [0.035 {+-} 0.007 {+-} 0.010]. From this the integral {Gamma}{sub 1}{sup p}-{Gamma}{sub 1}{sup n} followed, yielding 0.165 {+-} 0.009 {+-} 0.016 at Q{sup 2} = 3 (GeV/c){sup 2}, in agreement with the Bjorken sum rule to within one standard deviation. The Q{sup 2}-dependence of the ratio g{sub 1}/F{sub 1} was determined to be small for Q{sup 2} > 1 (GeV/c){sup 2}, validating the assumption of no Q{sup 2}-dependence used in obtaining the integrals. A small rise with increasing Q{sup 2} was seen in the ratio for Q{sup 2} < 1 (GeV/c){sup 2}, however. The total quark contribution to the spin was found to be {Delta}q = 0.28 {+-} 0.09 for the proton, and {Delta}q = 0.32 {+-} 0.05 for the deuteron. Furthermore, a large negative spin contribution from the strange sea quarks was measured for both nucleons, giving {Delta}s = 0.10 {+-} 0.03 and {Delta}s = -0

  5. Precision Measurement of the Rovibrational Energy-Level Structure of ^{4}He^{+}_{2}

    NASA Astrophysics Data System (ADS)

    Semeria, Luca; Jansen, Paul; Agner, Josef A.; Schmutz, Hansjürg; Merkt, Frederic

    2017-06-01

    He_{2}^{+} is a three-electron system for which highly accurate ab initio calculations are possible. The latest calculations of the rovibrational energies of He_{2}^{+} by Tung et al. have a reported accuracy of 120 MHz, although they do not include relativistic and quantum electrodynamics (QED) effects. We determined the rovibrational structure of ^{4}He^{+}_{2} from measurements of the Rydberg spectrum of metastable a ^3Σ_u^+ He_{2} (He^{*}_{2} hereafter) and Rydberg-series extrapolation using multichannel quantum-defect-theory. He^{*}_{2} molecules are produced in supersonic beams with velocities tunable down to about 100 m/s by combining a cryogenic supersonic-beam source with a multistage Zeeman decelerator. They are then excited to high-np Rydberg states by single-photon excitation. In the experiments, we use a pulsed uv laser system, with a near Fourier-transform-limited bandwidth of 150 MHz. The Zeeman deceleration reduces the systematic uncertainty arising from a possible Doppler shift and greatly simplifies the spectral assignment because of its spin-rotational state selectivity. Results will be presented on the rotational structure of the lowest three vibrational levels of He^{+}_{2}. The unprecedented accuracy that we have obtained for the v^{+}=0 rotational intervals of He_{2}^{+} enables the quantification of the relativistic and QED corrections by comparison with the results of Tung et al.^a W.-C. Tung, M. Pavanello and L. Adamowicz, J. Chem. Phys., 136, 104309, 2012. C. Jungen, Elements of Quantum Defect Theory, in : Handbook of High-resolution Spectroscopy, 2001. D. Sprecher, J. Liu, T. Krähenmann, M. Schäfer, and F. Merkt, J. Chem. Phys., 140, 064304, 2014. A. W. Wiederkehr, S. D. Hogan, M. Andrist, H. Schmutz, B. Lambillotte, J. A. Agner, and F. Merkt., J. Chem. Phys., 135, 214202, 2011. M. Motsch, P. Jansen, J. A. Agner, H. Schmutz, and F. Merkt, Phys. Rev. A, 89, 043420, 2014. P. Jansen, L. Semeria, L. E. Hofer, S. Scheidegger, J. A. Agner

  6. High-precision measurements of planetary spin states as probes of interior structure and processes (Invited)

    NASA Astrophysics Data System (ADS)

    Margot, J.

    2009-12-01

    Profound developments in our understanding of the Earth and Moon have arisen as a direct outcome of rotation studies (e.g., Munk and MacDonald 1960, Lambeck 1980, Wahr 1988, Dickey et al 1994). Measurements of planetary rotation provide powerful probes of planetary interior structure and processes. I will discuss ongoing observations at Mercury, Venus, and Titan, as well as future prospects for other bodies. Observations of radar speckle patterns tied to the rotation of Mercury establish that the planet occupies a Cassini state with obliquity 2.11 +/- 0.1 arcminutes. The measurements show that the planet exhibits librations in longitude that are forced at the 88-day orbital period, as predicted by theory. The amplitude of the oscillations together with spacecraft determinations of the gravitational harmonic coefficient C22 indicates that the mantle of Mercury is decoupled from a core that is at least partially molten. Departures from the exact Cassini state and long-term libration signatures can inform us about core-mantle interactions. New Cassini radar measurements of the spin state of Titan (Stiles et al 2008) can be most readily interpreted as evidence that Titan closely follows a Cassini state. Peale (1969) has shown that, in that state, a clear relationship exists between obliquity and moment of inertia differences. Application of this relationship to Titan in conjunction with measurements of the gravitational harmonic C22 yields a polar moment of inertia that exceeds the 2/5 value for a uniform density sphere, perhaps indicative of a decoupling between core and outer layer, as in Mercury. Libration measurements at Titan require new instrumentation but can provide superb probes of interior structure and dynamical interactions between layers. This also applies to Galilean satellites (Comstock and Bills 2003, Van Hoolst et al 2008). Ongoing measurements of length-of-day variations at Venus are most easily attributed to angular momentum exchange between

  7. Compact Short-Pulsed Electron Linac Based Neutron Sources for Precise Nuclear Material Analysis

    NASA Astrophysics Data System (ADS)

    Uesaka, M.; Tagi, K.; Matsuyama, D.; Fujiwara, T.; Dobashi, K.; Yamamoto, M.; Harada, H.

    2015-10-01

    An X-band (11.424GHz) electron linac as a neutron source for nuclear data study for the melted fuel debris analysis and nuclear security in Fukushima is under development. Originally we developed the linac for Compton scattering X-ray source. Quantitative material analysis and forensics for nuclear security will start several years later after the safe settlement of the accident is established. For the purpose, we should now accumulate more precise nuclear data of U, Pu, etc., especially in epithermal (0.1-10 eV) neutrons. Therefore, we have decided to modify and install the linac in the core space of the experimental nuclear reactor "Yayoi" which is now under the decommission procedure. Due to the compactness of the X-band linac, an electron gun, accelerating tube and other components can be installed in a small space in the core. First we plan to perform the time-of-flight (TOF) transmission measurement for study of total cross sections of the nuclei for 0.1-10 eV energy neutrons. Therefore, if we adopt a TOF line of less than 10m, the o-pulse length of generated neutrons should be shorter than 100 ns. Electronenergy, o-pulse length, power, and neutron yield are ~30 MeV, 100 ns - 1 micros, ~0.4 kW, and ~1011 n/s (~103 n/cm2/s at samples), respectively. Optimization of the design of a neutron target (Ta, W, 238U), TOF line and neutron detector (Ce:LiCAF) of high sensitivity and fast response is underway. We are upgrading the electron gun and a buncher to realize higher current and beam power with a reasonable beam size in order to avoid damage of the neutron target. Although the neutron flux is limited in case of the X-band electron linac based source, we take advantage of its short pulse aspect and availability for nuclear data measurement with a short TOF system. First, we form a tentative configuration in the current experimental room for Compton scattering in 2014. Then, after the decommissioning has been finished, we move it to the "Yayoi" room and perform

  8. Crystallization and melting of a branched polyethylene with precisely controlled chemical structure

    SciTech Connect

    Qui, Wulin; Pyda, Marek {nmn}; Nowak-Pyda, Elisabieta; Habenschuss, Anton {Tony}; Wagener, Kenneth; Wunderlich, Bernhard {nmn}

    2006-01-01

    The heat capacity of a linear polyethylene with dimethyl branches, at every 21st backbone atom was analyzed by differential scanning calorimetry (DSC) and quasi-isothermal temperature-modulated DSC. This novel copolyethylene (PE2M) is relatively difficult to crystallize from the melt. On subsequent heating, a first, sharp melting peak is followed by a sharp cold-crystallization and crystal perfection and a smaller endotherm, before reaching the main melting at 315-320 K, close to the melting temperatures of eicosane and tetracontane. The low-temperature melting is sensitive to the cooling rate and disappears below 1.0 K min-1. The cold crystallization can be avoided by heating with rates faster than 80 K min-1. The PE2M exhibits some reversing and reversible melting, which is typical for chain-folded polymers. The glass transition of semicrystalline PE2M is broadened and reaches its upper limit at about 260 K (midpoint at about 0.355 K). Above this temperature, the crystals seem to have a heat capacity similar to that of the liquid. A hypothesis is that the melting transition can be explained by changes in crystal perfection without major alteration of the crystal structure and the lamellar morphology.

  9. Determining the resolution of scanning microwave impedance microscopy using atomic-precision buried donor structures

    DOE PAGES

    Scrymgeour, D. A.; Baca, A.; Fishgrab, K.; ...

    2017-07-04

    To quantify the resolution limits of scanning microwave impedance microscopy (sMIM), we created scanning tunneling microscope (STM)-patterned donor nanostructures in silicon composed of 10 nm lines of highly conductive silicon buried under a protective top cap of silicon, and imaged them with sMIM. Here, this dopant pattern is an ideal test of the resolution and sensitivity of the sMIM technique, as it is made with nm-resolution and offers minimal complications from topography convolution. It has been determined that typical sMIM tips can resolve lines down to ~80 nm spacing, while resolution is independent of tip geometry as extreme tip wearmore » does not change the resolving power, contrary to traditional scanning capacitance microscopy (SCM). Going forward, sMIM is an ideal technique for qualifying buried patterned devices, potentially allowing for quantitative post-fabrication characterization of donor structures, which may be an important tool for the study of atomic-scale transistors and state of the art quantum computation schemes.« less

  10. High precision calibration of line structured light sensors based on linear transformation over triangular domain

    NASA Astrophysics Data System (ADS)

    Li, Yuehua; Zhou, Jingbo; Huang, Fengshan

    2016-09-01

    With the advantages of easy data processing and fast measuring speed, line structured light sensors (LSLSs) have gained more and more applications. CCD camera is a core component of the sensor. The distortion of its lens will severely degrades the measuring accuracy. To enhance the measuring quality, a numerical calibration method is brought out that is based on linear transformation over triangular domain. Based on the pinhole imaging principle, a linear transformation model was established which is easy to compute the profile's world coordinates according to its pixel coordinates over each triangular domain. The triangle domains are achieved using Delaunary triangulation via the centers of target dots. The triangle number that each center point of the laser stripe locates is determined by T-search method. A linear approximation error model to the lens distortion is also established and the approximation errors are getting larger when the interval spacing of the calibration dots increases. Measuring results show that the relative error of this proposed method in horizontal and vertical direction can reach 0.0630% and 0.0802%, respectively. The calibration error grows with the increasing of the target's dot interval that corresponds with the trends of the linear approximation error. This further validates the proposed calibration method.

  11. Probing Planetary Interior Structure And ProcessesWith High-precision Spin Measurements

    NASA Astrophysics Data System (ADS)

    Margot, Jean-Luc

    2011-04-01

    Measurements of planetary rotation provide powerful probes of planetary interior structure and processes. In this talk I will describe results and prospects for Mercury, Venus, and Europa. Observations of radar speckle patterns tied to the rotation of Mercury establish that the planet exhibits periodic variations in length-of-day. The amplitude of the oscillations indicates that the mantle of Mercury is decoupled from a molten outer core. Long-term signatures may reveal core-mantle interactions. Ongoing measurements of Venus show that its spin period is not constant. The variations are compatible with percent-level changes in atmospheric angular momentum transferred to the solid planet. Monitoring these fluctuations can provide key constraints on the atmospheric dynamics and climate of Venus. Several lines of evidence suggest that a subsurface ocean exists beneath an icy shell on Europa. The shell most likely exhibits periodic spin variations that may be detectable from Earth. The amplitude of the oscillations depend on the rheology and thickness of the shell, perhaps the most important determinants of Europa's astrobiological potential.

  12. Precision measurement of the proton and deuteron spin structure functions g2 and asymmetries A2

    NASA Astrophysics Data System (ADS)

    E155 Collaboration; Anthony, P. L.; Arnold, R. G.; Averett, T.; Band, H. R.; Benmouna, N.; Boeglin, W.; Borel, H.; Bosted, P. E.; Bültmann, S. L.; Court, G. R.; Crabb, D.; Day, D.; Decowski, P.; Depietro, P.; Egiyan, H.; Erbacher, R.; Erickson, R.; Fatemi, R.; Frlez, E.; Griffioen, K. A.; Harris, C.; Hughes, E. W.; Hyde-Wright, C.; Igo, G.; Johnson, J.; King, P.; Kramer, K.; Kuhn, S. E.; Lawrence, D.; Liang, Y.; Lindgren, R.; Lombard-Nelsen, R. M.; McKee, P.; McNulty, D. E.; Meyer, W.; Mitchell, G. S.; Mitchell, J.; Olson, M.; Penttila, S.; Peterson, G. A.; Pitthan, R.; Pocanic, D.; Prepost, R.; Prescott, C.; Raue, B. A.; Reyna, D.; Ryan, P.; Rochester, L. S.; Rock, S.; Rondon-Aramayo, O.; Sabatie, F.; Smith, T.; Sorrell, L.; Lorant, S. St.; Szalata, Z.; Terrien, Y.; Tobias, A.; Toole, T.; Trentalange, S.; Wesselmann, F. R.; Wright, T. R.; Zeier, M.; Zhu, H.; Zihlmann, B.

    2003-01-01

    We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range /0.02<=x<=0.8 and 0.7<=Q2<=20GeV2 by scattering 29.1 and 32.3 GeV longitudinally polarized electrons from transversely polarized NH3 and 6LiD targets. Our measured g2 approximately follows the twist-2 Wandzura-Wilczek calculation. The twist-3 reduced matrix elements d2p and d2n are less than two standard deviations from zero. The data are inconsistent with the Burkhardt-Cottingham sum rule if there is no pathological behavior as /x-->0. The Efremov-Leader-Teryaev integral is consistent with zero within our measured kinematic range. The absolute value of A2 is significantly smaller than the A2<√R(1+A1)/2 limit.

  13. Calculation of measurement uncertainty in quantitative analysis of genetically modified organisms using intermediate precision--a practical approach.

    PubMed

    Zel, Jana; Gruden, Kristina; Cankar, Katarina; Stebih, Dejan; Blejec, Andrej

    2007-01-01

    Quantitative characterization of nucleic acids is becoming a frequently used method in routine analysis of biological samples, one use being the detection of genetically modified organisms (GMOs). Measurement uncertainty is an important factor to be considered in these analyses, especially where precise thresholds are set in regulations. Intermediate precision, defined as a measure between repeatability and reproducibility, is a parameter describing the real situation in laboratories dealing with quantitative aspects of molecular biology methods. In this paper, we describe the top-down approach to calculating measurement uncertainty, using intermediate precision, in routine GMO testing of food and feed samples. We illustrate its practicability in defining compliance of results with regulations. The method described is also applicable to other molecular methods for a variety of laboratory diagnostics where quantitative characterization of nucleic acids is needed.

  14. Limited proteolysis and peptide mapping for comparability of biopharmaceuticals: An evaluation of repeatability, intra-assay precision and capability to detect structural change.

    PubMed

    Perrin, Camille; Burkitt, Will; Perraud, Xavier; O'Hara, John; Jone, Carl

    2016-05-10

    The use of limited proteolysis followed by peptide mapping for the comparability of the higher-order structure of biopharmaceuticals was investigated. In this approach the proteolysis is performed under non-reducing and non-denaturing conditions, and the resulting peptide map is determined by the samples primary and higher order structures. This allows comparability of biopharmaceuticals to be made in terms of their higher order structure, using a method that is relatively simple to implement. The digestion of a monoclonal antibody under non-denaturing conditions was analyzed using peptide mapping, circular dichroism (CD) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This allowed an optimal digestion time to be chosen. This method was then assessed for its ability to detect structural change using a monoclonal antibody, which had been subjected to a range of stresses; deglycosylation, mild denaturation and a batch that had failed specifications due to in-process reduction. The repeatability and inter-assay precision were assessed. It was demonstrated that the limited proteolysis peptide maps of the three stressed samples were significantly different to control samples and that the differences observed were consistent between the occasions when the assays were run. A combination of limited proteolysis and CD or SDS-PAGE analysis was shown to enhance the capacity of these techniques to detect structural change, which otherwise would not have been observed. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Size Dependence of Atomically Precise Gold Nanoclusters in Chemoselective Hydrogenation and Active Site Structure

    SciTech Connect

    Li, Gao; Jiang, Deen; Kumar, Santosh; Chen, Yuxiang; Jin, Rongchao

    2014-01-01

    We here investigate the catalytic properties of water-soluble Aun(SG)m nanocluster catalysts (H-SG = glutathione) of different sizes, including Au15(SG)13, Au18(SG)14, Au25(SG)18, Au38(SG)24, and captopril-capped Au25(Capt)18 nanoclusters. These Aun(SR)m nanoclusters (-SR represents thiolate generally) are used as homogeneous catalysts (i.e., without supports) in the chemoselective hydrogenation of 4-nitrobenzaldehyde (4-NO2PhCHO) to 4-nitrobenzyl alcohol (4-NO2PhCH2OH) in water with H2 gas (20 bar) as the hydrogen source. These nanocluster catalysts, except Au18(SG)14, remain intact after the catalytic reaction, evidenced by UV-vis spectra which are characteristic of each sized nanoclusters and thus serve as spectroscopic fingerprints . We observe a drastic size-dependence and steric effect of protecting ligands on the gold nanocluster catalysts in the hydrogenation reaction. Density functional theory (DFT) modeling of the 4-nitrobenzaldehyde adsorption shows that both the CHO and NO2 groups are in close interact with the S-Au-S staples on the gold nanocluster surface; the adsorption of the 4-nitrobenzaldehyde molecule on the four different sized Aun(SR)m nanoclusters are moderately strong and similar in strength. The DFT results suggest that the catalytic activity of the Aun(SR)m nanoclusters is primarily determined by the surface area of the Au nanocluster, consistent with the observed trend of the conversion of 4-nitrobenzaldehyde versus the cluster size. Overall, this work offers the molecular insight into the hydrogenation of 4-nitrobenzaldehyde and the catalytically active site structure on gold nanocluster catalysts.

  16. Analysis of structures causing instabilities.

    PubMed

    Wilhelm, Thomas

    2007-07-01

    We present a simple new method to systematically identify all topological structures (e.g., positive feedback loops) potentially leading to locally unstable steady states: ICSA-The instability causing structure analysis. Systems without any instability causing structure (i.e., not fulfilling the necessary topological condition for instabilities) cannot have unstable steady states. It follows that common bistability or multistability and Hopf bifurcations are excluded and sustained oscillations and deterministic chaos are most unlikely. The ICSA leads to new insights into the topological organization of chemical and biochemical systems, such as metabolic, gene regulatory, and signal transduction networks.

  17. Towards Precise Constraints on the Chemical Compositions and Thermal Structures of Giant Exoplanets with a JWST GTO Program

    NASA Astrophysics Data System (ADS)

    Bean, Jacob; Lunine, Jonathan I.

    2017-06-01

    The chemical compositions and thermal structures of close-in planets are two of the major questions raised over the last 15+ years of exoplanet atmospheric characterization. These are fundamental questions in their own right, and answering them also has the potential to improve our understanding of the planets in the Solar System. JWST offers the opportunity to make a major advance on these topics by revealing a more complete and accurate inventory of the chemical species in exoplanet atmospheres and by precisely measuring atmospheric temperatures over a broad range of pressures. I will describe how we plan to use an Interdisciplinary Scientist GTO program to determine the compositions and thermal structures of transiting, hot giant exoplanets using dayside thermal emission measurements obtained at secondary eclipse. Our composition measurements are focused on determining absolute molecular abundances as a tracer of atmospheric metallicity and the abundance ratio of carbon to oxygen. The targets in our program have a range of masses and irradiation, which will enable us to test theories of how atmospheric metallicity varies with planet mass and how thermal structures respond to different levels of stellar forcing.

  18. Remote Analysis of Regional Lunar Pyroclastic Deposits - Consistency and Precision of LRO Diviner Estimates

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.; Greenhagen, Benjamin T.; Paige, David A.

    2014-01-01

    Allen et al. recently published a new method of estimating the FeO abundances of lunar pyroclastic deposits. This method is derived from orbital thermal infrared measurements by the Diviner Lunar Radiometer Experiment on the Lunar Reconnaissance Orbiter (LRO) spacecraft. The present study utilizes Diviner data from the Taurus Littrow regional pyroclastic deposit to assess the consistency and precision of such estimates.

  19. Rapid, Precise, and Economical Analysis of Data from the Southern California Integrated GPS Network

    NASA Technical Reports Server (NTRS)

    Zumberge, J. F.; Muellerschoen, R. J.; Watkins, M. M.

    1995-01-01

    The number of permanently operating precision Global Positioning System (GPS) receivers in the Southern California Integrated GPS Network has increased dramatically in the past year to several dozen. This number is expected to increase to hundreds within a few years. A prototype system to process all of these data, accurately, rapidly, and economically, has been in operation since May 1995.

  20. Rapid, Precise, and Economical Analysis of Data from the Southern California Integrated GPS Network

    NASA Technical Reports Server (NTRS)

    Zumberge, J. F.; Muellerschoen, R. J.; Watkins, M. M.

    1995-01-01

    The number of permanently operating precision Global Positioning System (GPS) receivers in the Southern California Integrated GPS Network has increased dramatically in the past year to several dozen. This number is expected to increase to hundreds within a few years. A prototype system to process all of these data, accurately, rapidly, and economically, has been in operation since May 1995.

  1. Bias and precision analysis of diffusional kurtosis imaging for different acquisition schemes.

    PubMed

    Sprenger, Tim; Sperl, Jonathan I; Fernandez, Brice; Golkov, Vladimir; Eidner, Ines; Sämann, Philipp G; Czisch, Michael; Tan, Ek T; Hardy, Christopher J; Marinelli, Luca; Haase, Axel; Menzel, Marion I

    2016-12-01

    Diffusional kurtosis imaging (DKI) is an approach to characterizing the non-Gaussian fraction of water diffusion in biological tissue. However, DKI is highly susceptible to the low signal-to-noise ratio of diffusion-weighted images, causing low precision and a significant bias due to Rician noise distribution. Here, we evaluate precision and bias using weighted linear least squares fitting of different acquisition schemes including several multishell schemes, a diffusion spectrum imaging (DSI) scheme, as well as a compressed sensing reconstruction of undersampled DSI scheme. Monte Carlo simulations were performed to study the three-dimensional distribution of the apparent kurtosis coefficient (AKC). Experimental data were acquired from one healthy volunteer with multiple repetitions, using the same acquisition schemes as for the simulations. The angular distribution of the bias and precision were very inhomogeneous. While axial kurtosis was significantly overestimated, radial kurtosis was underestimated. The precision of radial kurtosis was up to 10-fold lower than axial kurtosis. The noise bias behavior of DKI is highly complex and can cause overestimation as well as underestimation of the AKC even within one voxel. The acquisition scheme with three shells, suggested by Poot et al, provided overall the best performance. Magn Reson Med 76:1684-1696, 2016. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  2. Structural Analysis of Communication Development.

    ERIC Educational Resources Information Center

    Conville, Richard L.

    This paper discusses the question of the legitimacy of applying structural analysis to actual human behavior and illustrates its legitimacy by using the reasoning in an essay by Paul Ricoeur. It then asks if the principles of communication development (obliqueness, exchange, and dying) derived from Helen Keller's experience of communication…

  3. Structural Analysis of Communication Development.

    ERIC Educational Resources Information Center

    Conville, Richard L.

    This paper discusses the question of the legitimacy of applying structural analysis to actual human behavior and illustrates its legitimacy by using the reasoning in an essay by Paul Ricoeur. It then asks if the principles of communication development (obliqueness, exchange, and dying) derived from Helen Keller's experience of communication…

  4. The effects of structure anisotropy on lensing observables in an exact general relativistic setting for precision cosmology

    SciTech Connect

    Troxel, M. A.; Ishak, Mustapha; Peel, Austin E-mail: mishak@utdallas.edu

    2014-03-01

    The study of relativistic, higher order, and nonlinear effects has become necessary in recent years in the pursuit of precision cosmology. We develop and apply here a framework to study gravitational lensing in exact models in general relativity that are not restricted to homogeneity and isotropy, and where full nonlinearity and relativistic effects are thus naturally included. We apply the framework to a specific, anisotropic galaxy cluster model which is based on a modified NFW halo density profile and described by the Szekeres metric. We examine the effects of increasing levels of anisotropy in the galaxy cluster on lensing observables like the convergence and shear for various lensing geometries, finding a strong nonlinear response in both the convergence and shear for rays passing through anisotropic regions of the cluster. Deviation from the expected values in a spherically symmetric structure are asymmetric with respect to path direction and thus will persist as a statistical effect when averaged over some ensemble of such clusters. The resulting relative difference in various geometries can be as large as approximately 2%, 8%, and 24% in the measure of convergence (1−κ) for levels of anisotropy of 5%, 10%, and 15%, respectively, as a fraction of total cluster mass. For the total magnitude of shear, the relative difference can grow near the center of the structure to be as large as 15%, 32%, and 44% for the same levels of anisotropy, averaged over the two extreme geometries. The convergence is impacted most strongly for rays which pass in directions along the axis of maximum dipole anisotropy in the structure, while the shear is most strongly impacted for rays which pass in directions orthogonal to this axis, as expected. The rich features found in the lensing signal due to anisotropic substructure are nearly entirely lost when one treats the cluster in the traditional FLRW lensing framework. These effects due to anisotropic structures are thus likely to

  5. Structural Analysis and Design Software

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Collier Research and Development Corporation received a one-of-a-kind computer code for designing exotic hypersonic aircraft called ST-SIZE in the first ever Langley Research Center software copyright license agreement. Collier transformed the NASA computer code into a commercial software package called HyperSizer, which integrates with other Finite Element Modeling and Finite Analysis private-sector structural analysis program. ST-SIZE was chiefly conceived as a means to improve and speed the structural design of a future aerospace plane for Langley Hypersonic Vehicles Office. Including the NASA computer code into HyperSizer has enabled the company to also apply the software to applications other than aerospace, including improved design and construction for offices, marine structures, cargo containers, commercial and military aircraft, rail cars, and a host of everyday consumer products.

  6. QA system for structural analysis

    NASA Astrophysics Data System (ADS)

    Raiko, Heikki

    The activities to be addressed by an organization involved in structural analysis by numerical methods and/or development and maintenance of such computer codes or systems are described. The requirements are based on International Standard 9001. The interpretation of the requirements is done according to an application presented by a Quality Analysis (QA) working group. The purpose of a quality analysis system is to help anyone to do a better job. Emphasis on technical documentation to speed up operations is recommended. The first steps in implementing a finite element quality assurance system in an organization are as follows: constitute a technical body with responsibility and authority for the analysis quality system; agree on management responsibilities for each quality analysis activity; and review current practices against the quality system standard requirements. Experience shows that it is mainly a process of rationalizing, formalizing, and reinforcing existing practices.

  7. Precise ground motion measurements to support multi-hazard analysis in Jakarta

    NASA Astrophysics Data System (ADS)

    Koudogbo, Fifamè; Duro, Javier; Garcia Robles, Javier; Abidin, Hasanuddin Z.

    2015-04-01

    Jakarta is the capital of Indonesia and is home to approximately 10 million people on the coast of the Java Sea. The Capital District of Jakarta (DKI) sits in the lowest lying areas of the basin. Its topography varies, with the northern part just meters above current sea level and lying on a flood plain. Subsequently, this portion of the city frequently floods. Flood events have been increasing in severity during the past decade. The February 2007 event inundated 235 Km2 (about 36%) of the city, by up to seven meters in some areas. This event affected more than 2.6 million people; the estimated financial and economic losses from this event amounted to US900 million [1][2]. Inundations continue to occur under any sustained rainfall conditions. Flood events in Jakarta are expected to become more frequent in coming years, with a shift from previously slow natural processes with low frequency to a high frequency process resulting in severe socio-economic damage. Land subsidence in Jakarta results in increased vulnerability to flooding due to the reduced gravitational capacity to channel storm flows to the sea and an increased risk of tidal flooding. It continues at increasingly alarming rates, principally caused by intensive deep groundwater abstraction [3]. Recent studies have found typical subsidence rates of 7.5-10 cm a year. In localized areas of north Jakarta subsidence in the range 15-25 cm a year is occurring which, if sustained, would result in them sinking to 4-5 m below sea level by 2025 [3]. ALTAMIRA INFORMATION, company specialized in ground motion monitoring, has developed GlobalSARTM, which combines several processing techniques and algorithms based on InSAR technology, to achieve ground motion measurements with millimetric precision and high accuracy [4]. Within the RASOR (Rapid Analysis and Spatialisation and Of Risk) project, ALTAMIRA INFORMATION will apply GlobalSARTM to assess recent land subsidence in Jakarta, based on the processing of Very High

  8. Precision galactic structure

    SciTech Connect

    Kent, S.M.

    2001-01-04

    Optical and IR surveys in progress or in the planning stages will lead to substantial improvements in our picture of the Milky Way as a consequence of their providing large volumes of data with much improved photometric and positional measurements compared with existing datasets.

  9. Precision Measurement.

    ERIC Educational Resources Information Center

    Radius, Marcie; And Others

    The manual provides information for precision measurement (counting of movements per minute of a chosen activity) of achievement in special education students. Initial sections give guidelines for the teacher, parent, and student to follow for various methods of charting behavior. It is explained that precision measurement is a way to measure the…

  10. Post-buckling analysis for the precisely controlled buckling of thin film encapsulated by elastomeric subsrates.

    SciTech Connect

    Jiang, H.; Sun, Y.; Rogers, J. A.; Huang, Y.; Arizona State Univ.; Univ. of Illinois; Northwestern Univ.

    2008-04-01

    The precisely controlled buckling of stiff thin films (e.g., Si or GaAs nano ribbons) on the patterned surface of elastomeric substrate (e.g., poly(dimethylsiloxane) (PDMS)) with periodic inactivated and activated regions was designed by Sun et al. [Sun, Y., Choi, W.M., Jiang, H., Huang, Y.Y., Rogers, J.A., 2006. Controlled buckling of semiconductor nanoribbons for stretchable electronics. Nature Nanotechnology 1, 201-207] for important applications of stretchable electronics. We have developed a post-buckling model based on the energy method for the precisely controlled buckling to study the system stretchability. The results agree with Sun et al.'s (2006) experiments without any parameter fitting, and the system can reach 120% stretchability.

  11. Precision Pointing Control System (PPCS) system design and analysis. [for gimbaled experiment platforms

    NASA Technical Reports Server (NTRS)

    Frew, A. M.; Eisenhut, D. F.; Farrenkopf, R. L.; Gates, R. F.; Iwens, R. P.; Kirby, D. K.; Mann, R. J.; Spencer, D. J.; Tsou, H. S.; Zaremba, J. G.

    1972-01-01

    The precision pointing control system (PPCS) is an integrated system for precision attitude determination and orientation of gimbaled experiment platforms. The PPCS concept configures the system to perform orientation of up to six independent gimbaled experiment platforms to design goal accuracy of 0.001 degrees, and to operate in conjunction with a three-axis stabilized earth-oriented spacecraft in orbits ranging from low altitude (200-2500 n.m., sun synchronous) to 24 hour geosynchronous, with a design goal life of 3 to 5 years. The system comprises two complementary functions: (1) attitude determination where the attitude of a defined set of body-fixed reference axes is determined relative to a known set of reference axes fixed in inertial space; and (2) pointing control where gimbal orientation is controlled, open-loop (without use of payload error/feedback) with respect to a defined set of body-fixed reference axes to produce pointing to a desired target.

  12. Crystal structure of a novel RNA motif that allows for precise positioning of a single metal ion.

    PubMed

    Kanazawa, Hiroki; Kondo, Jiro

    2017-11-01

    We have determined a crystal structure of an RNA duplex containing a novel metal-binding motif. The motif is composed of two sheared G○A base pairs, two unpaired A residues and four phosphate groups in close proximity. Four A residues make an A-A-A-A stacking column at the minor groove side and two G bases are highly inclined, thereby forming the pocket-shaped motif at the major groove side. In the present structure, a hydrated Sr(2+) ion exists in the pocket and binds to the O6 and N7 atoms of the two G bases and four phosphate groups. According to the previously-reported metal-binding properties to RNA molecules, many of divalent cations, such as Mg(2+), Mn(2+), Co(2+), Zn(2+), Ba(2+), Pb(2+) and Cd(2+), may bind to the motif. This metal-binding motif can be used as a modular building block that allows for precise positioning of a single metal ion in functional nucleic acid molecules. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Templated Atom-Precise Galvanic Synthesis and Structure Elucidation of a [Ag24Au(SR)18](-) Nanocluster.

    PubMed

    Bootharaju, Megalamane S; Joshi, Chakra P; Parida, Manas R; Mohammed, Omar F; Bakr, Osman M

    2016-01-18

    Synthesis of atom-precise alloy nanoclusters with uniform composition is challenging when the alloying atoms are similar in size (for example, Ag and Au). A galvanic exchange strategy has been devised to produce a compositionally uniform [Ag24Au(SR)18](-) cluster (SR: thiolate) using a pure [Ag25(SR)18](-) cluster as a template. Conversely, the direct synthesis of Ag24Au cluster leads to a mixture of [Ag(25-x)Au(x)(SR)18](-), x=1-8. Mass spectrometry and crystallography of [Ag24Au(SR)18](-) reveal the presence of the Au heteroatom at the Ag25 center, forming Ag24Au. The successful exchange of the central Ag of Ag25 with Au causes perturbations in the Ag25 crystal structure, which are reflected in the absorption, luminescence, and ambient stability of the particle. These properties are compared with those of Ag25 and Ag24Pd clusters with same ligand and structural framework, providing new insights into the modulation of cluster properties with dopants at the single-atom level.

  14. Effects of experimental design on calibration curve precision in routine analysis

    PubMed Central

    Pimentel, Maria Fernanda; Neto, Benício de Barros; Saldanha, Teresa Cristina B.

    1998-01-01

    A computational program which compares the effciencies of different experimental designs with those of maximum precision (D-optimized designs) is described. The program produces confidence interval plots for a calibration curve and provides information about the number of standard solutions, concentration levels and suitable concentration ranges to achieve an optimum calibration. Some examples of the application of this novel computational program are given, using both simulated and real data. PMID:18924816

  15. Efficient Analysis of Complex Structures

    NASA Technical Reports Server (NTRS)

    Kapania, Rakesh K.

    2000-01-01

    Last various accomplishments achieved during this project are : (1) A Survey of Neural Network (NN) applications using MATLAB NN Toolbox on structural engineering especially on equivalent continuum models (Appendix A). (2) Application of NN and GAs to simulate and synthesize substructures: 1-D and 2-D beam problems (Appendix B). (3) Development of an equivalent plate-model analysis method (EPA) for static and vibration analysis of general trapezoidal built-up wing structures composed of skins, spars and ribs. Calculation of all sorts of test cases and comparison with measurements or FEA results. (Appendix C). (4) Basic work on using second order sensitivities on simulating wing modal response, discussion of sensitivity evaluation approaches, and some results (Appendix D). (5) Establishing a general methodology of simulating the modal responses by direct application of NN and by sensitivity techniques, in a design space composed of a number of design points. Comparison is made through examples using these two methods (Appendix E). (6) Establishing a general methodology of efficient analysis of complex wing structures by indirect application of NN: the NN-aided Equivalent Plate Analysis. Training of the Neural Networks for this purpose in several cases of design spaces, which can be applicable for actual design of complex wings (Appendix F).

  16. Efficient Analysis of Complex Structures

    NASA Technical Reports Server (NTRS)

    Kapania, Rakesh K.

    2000-01-01

    Last various accomplishments achieved during this project are : (1) A Survey of Neural Network (NN) applications using MATLAB NN Toolbox on structural engineering especially on equivalent continuum models (Appendix A). (2) Application of NN and GAs to simulate and synthesize substructures: 1-D and 2-D beam problems (Appendix B). (3) Development of an equivalent plate-model analysis method (EPA) for static and vibration analysis of general trapezoidal built-up wing structures composed of skins, spars and ribs. Calculation of all sorts of test cases and comparison with measurements or FEA results. (Appendix C). (4) Basic work on using second order sensitivities on simulating wing modal response, discussion of sensitivity evaluation approaches, and some results (Appendix D). (5) Establishing a general methodology of simulating the modal responses by direct application of NN and by sensitivity techniques, in a design space composed of a number of design points. Comparison is made through examples using these two methods (Appendix E). (6) Establishing a general methodology of efficient analysis of complex wing structures by indirect application of NN: the NN-aided Equivalent Plate Analysis. Training of the Neural Networks for this purpose in several cases of design spaces, which can be applicable for actual design of complex wings (Appendix F).

  17. High Precision Oxygen Three Isotope Analysis of Wild-2 Particles and Anhydrous Chondritic Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Nakashima, D.; Ushikubo, T.; Zolensky, Michael E.; Weisberg, M. K.; Joswiak, D. J.; Brownlee, D. E.; Matrajt, G.; Kita, N. T.

    2011-01-01

    One of the most important discoveries from comet Wild-2 samples was observation of crystalline silicate particles that resemble chondrules and CAIs in carbonaceous chondrites. Previous oxygen isotope analyses of crystalline silicate terminal particles showed heterogeneous oxygen isotope ratios with delta(sup 18)O to approx. delta(sup 17)O down to -50% in the CAI-like particle Inti, a relict olivine grain in Gozen-sama, and an olivine particle. However, many Wild-2 particles as well as ferromagnesian silicates in anhydrous interplanetary dust particles (IDPs) showed Delta(sup 17)O values that cluster around -2%. In carbonaceous chondrites, chondrules seem to show two major isotope reservoirs with Delta(sup 17)O values at -5% and -2%. It was suggested that the Delta(sup 17)O = -2% is the common oxygen isotope reservoir for carbonaceous chondrite chondrules and cometary dust, from the outer asteroid belt to the Kuiper belt region. However, a larger dataset with high precision isotope analyses (+/-1-2%) is still needed to resolve the similarities or distinctions among Wild-2 particles, IDPs and chondrules in meteorites. We have made signifi-cant efforts to establish routine analyses of small particles (< or =10micronsm) at 1-2% precision using IMS-1280 at WiscSIMS laboratory. Here we report new results of high precision oxygen isotope analyses of Wild-2 particles and anhydrous chondritic IDPs, and discuss the relationship between the cometary dust and carbonaceous chondrite chondrules.

  18. Single photon ranging system using two wavelengths laser and analysis of precision

    NASA Astrophysics Data System (ADS)

    Chen, Yunfei; He, Weiji; Miao, Zhuang; Gu, Guohua; Chen, Qian

    2013-09-01

    The laser ranging system based on time correlation single photon counting technology and single photon detector has the feature of high precision and low emergent energy etc. In this paper, we established a single photon laser ranging system that use the supercontinuum laser as light source, and two wavelengths (532nm and 830nm) of echo signal as the stop signal. We propose a new method that is capable to improve the single photon ranging system performance. The method is implemented by using two single-photon detectors to receive respectively the two different wavelength signals at the same time. We extracted the firings of the two detectors triggered by the same laser pulse at the same time and then took mean time of the two firings as the combined detection time-of-flight. The detection by two channels using two wavelengths will effectively improve the detection precision and decrease the false alarm probability. Finally, an experimental single photon ranging system was established. Through a lot of experiments, we got the system precision using both single and two wavelengths and verified the effectiveness of the method.

  19. Structural analysis of vibroacoustical processes

    NASA Technical Reports Server (NTRS)

    Gromov, A. P.; Myasnikov, L. L.; Myasnikova, Y. N.; Finagin, B. A.

    1973-01-01

    The method of automatic identification of acoustical signals, by means of the segmentation was used to investigate noises and vibrations in machines and mechanisms, for cybernetic diagnostics. The structural analysis consists of presentation of a noise or vibroacoustical signal as a sequence of segments, determined by the time quantization, in which each segment is characterized by specific spectral characteristics. The structural spectrum is plotted as a histogram of the segments, also as a relation of the probability density of appearance of a segment to the segment type. It is assumed that the conditions of ergodic processes are maintained.

  20. Structured Functional Principal Component Analysis

    PubMed Central

    Shou, Haochang; Zipunnikov, Vadim; Crainiceanu, Ciprian M.; Greven, Sonja

    2015-01-01

    Summary Motivated by modern observational studies, we introduce a class of functional models that expand nested and crossed designs. These models account for the natural inheritance of the correlation structures from sampling designs in studies where the fundamental unit is a function or image. Inference is based on functional quadratics and their relationship with the underlying covariance structure of the latent processes. A computationally fast and scalable estimation procedure is developed for high-dimensional data. Methods are used in applications including high-frequency accelerometer data for daily activity, pitch linguistic data for phonetic analysis, and EEG data for studying electrical brain activity during sleep. PMID:25327216

  1. Quantifying Vegetation Change in Semiarid Environments: Precision and Accuracy of Spectral Mixture Analysis and the Normalized Difference Vegetation Index

    NASA Technical Reports Server (NTRS)

    Elmore, Andrew J.; Mustard, John F.; Manning, Sara J.; Elome, Andrew J.

    2000-01-01

    Because in situ techniques for determining vegetation abundance in semiarid regions are labor intensive, they usually are not feasible for regional analyses. Remotely sensed data provide the large spatial scale necessary, but their precision and accuracy in determining vegetation abundance and its change through time have not been quantitatively determined. In this paper, the precision and accuracy of two techniques, Spectral Mixture Analysis (SMA) and Normalized Difference Vegetation Index (NDVI) applied to Landsat TM data, are assessed quantitatively using high-precision in situ data. In Owens Valley, California we have 6 years of continuous field data (1991-1996) for 33 sites acquired concurrently with six cloudless Landsat TM images. The multitemporal remotely sensed data were coregistered to within 1 pixel, radiometrically intercalibrated using temporally invariante surface features and geolocated to within 30 m. These procedures facilitated the accurate location of field-monitoring sites within the remotely sensed data. Formal uncertainties in the registration, radiometric alignment, and modeling were determined. Results show that SMA absolute percent live cover (%LC) estimates are accurate to within ?4.0%LC and estimates of change in live cover have a precision of +/-3.8%LC. Furthermore, even when applied to areas of low vegetation cover, the SMA approach correctly determined the sense of clump, (i.e., positive or negative) in 87% of the samples. SMA results are superior to NDVI, which, although correlated with live cover, is not a quantitative measure and showed the correct sense of change in only 67%, of the samples.

  2. HOST structural analysis program overview

    NASA Technical Reports Server (NTRS)

    Thompson, Robert L.

    1986-01-01

    Hot-section components of aircraft gas turbine engines are subjected to severe thermal structural loading conditions, especially during the startup and takeoff portions of the engine cycle. The most severe and damaging stresses and strains are those induced by the steep thermal gradients induced during the startup transient. These transient stresses and strains are also the most difficult to predict, in part because the temperature gradients and distributions are not well known or readily predictable and, in part, because the cyclic elastic-viscoplastic behavior of the materials at these extremes of temperature and strain are not well known or readily predictable. A broad spectrum of structures related technology programs is underway to address these deficiencies at the basic as well as the applied level. The three key program elements in the HOST structural analysis program are computations, constitutive modeling, and experiments for each research activity. Also shown are tables summarizing each of the activities.

  3. Optimal tracers for parallel labeling experiments and (13)C metabolic flux analysis: A new precision and synergy scoring system.

    PubMed

    Crown, Scott B; Long, Christopher P; Antoniewicz, Maciek R

    2016-11-01

    (13)C-Metabolic flux analysis ((13)C-MFA) is a widely used approach in metabolic engineering for quantifying intracellular metabolic fluxes. The precision of fluxes determined by (13)C-MFA depends largely on the choice of isotopic tracers and the specific set of labeling measurements. A recent advance in the field is the use of parallel labeling experiments for improved flux precision and accuracy. However, as of today, no systemic methods exist for identifying optimal tracers for parallel labeling experiments. In this contribution, we have addressed this problem by introducing a new scoring system and evaluating thousands of different isotopic tracer schemes. Based on this extensive analysis we have identified optimal tracers for (13)C-MFA. The best single tracers were doubly (13)C-labeled glucose tracers, including [1,6-(13)C]glucose, [5,6-(13)C]glucose and [1,2-(13)C]glucose, which consistently produced the highest flux precision independent of the metabolic flux map (here, 100 random flux maps were evaluated). Moreover, we demonstrate that pure glucose tracers perform better overall than mixtures of glucose tracers. For parallel labeling experiments the optimal isotopic tracers were [1,6-(13)C]glucose and [1,2-(13)C]glucose. Combined analysis of [1,6-(13)C]glucose and [1,2-(13)C]glucose labeling data improved the flux precision score by nearly 20-fold compared to widely use tracer mixture 80% [1-(13)C]glucose +20% [U-(13)C]glucose.

  4. Precision Medicine

    PubMed Central

    Cholerton, Brenna; Larson, Eric B.; Quinn, Joseph F.; Zabetian, Cyrus P.; Mata, Ignacio F.; Keene, C. Dirk; Flanagan, Margaret; Crane, Paul K.; Grabowski, Thomas J.; Montine, Kathleen S.; Montine, Thomas J.

    2017-01-01

    Three key elements to precision medicine are stratification by risk, detection of pathophysiological processes as early as possible (even before clinical presentation), and alignment of mechanism of action of intervention(s) with an individual's molecular driver(s) of disease. Used for decades in the management of some rare diseases and now gaining broad currency in cancer care, a precision medicine approach is beginning to be adapted to cognitive impairment and dementia. This review focuses on the application of precision medicine to address the clinical and biological complexity of two common neurodegenerative causes of dementia: Alzheimer disease and Parkinson disease. PMID:26724389

  5. Precision theoretical analysis of neutron radiative beta decay to order O (α2/π2)

    NASA Astrophysics Data System (ADS)

    Ivanov, A. N.; Höllwieser, R.; Troitskaya, N. I.; Wellenzohn, M.; Berdnikov, Ya. A.

    2017-06-01

    In the Standard Model (SM) we calculate the decay rate of the neutron radiative β- decay to order O (α2/π2˜10-5), where α is the fine-structure constant, and radiative corrections to order O (α /π ˜10-3). The obtained results together with the recent analysis of the neutron radiative β- decay to next-to-leading order in the large proton-mass expansion, performed by Ivanov et al. [Phys. Rev. D 95, 033007 (2017), 10.1103/PhysRevD.95.033007], describe recent experimental data by the RDK II Collaboration [Bales et al., Phys. Rev. Lett. 116, 242501 (2016), 10.1103/PhysRevLett.116.242501] within 1.5 standard deviations. We argue a substantial influence of strong low-energy interactions of hadrons coupled to photons on the properties of the amplitude of the neutron radiative β- decay under gauge transformations of real and virtual photons.

  6. An Investigation on the Reliability of Deformation Analysis at Simulated Network Depending on the Precise Point Position Technique

    NASA Astrophysics Data System (ADS)

    Durdag, U. M.; Erdogan, B.; Hekimoglu, S.

    2014-12-01

    Deformation analysis plays an important role for human life safety; hence investigating the reliability of the obtained results from deformation analysis is crucial. The deformation monitoring network is established and the observations are analyzed periodically. The main problem in the deformation analysis is that if there is more than one displaced point in the monitoring network, the analysis methods smear the disturbing effects of the displaced points over all other points which are not displaced. Therefore, only one displaced point can be detected successfully. The Precise Point Positioning (PPP) gives opportunity to prevent smearing effect of the displaced points. In this study, we have simulated a monitoring network that consisting four object points and generated six different scenarios. The displacements were added to the points by using a device that the GPS antenna was easily moved horizontally and the seven hours static GPS measurements were carried out. The measurements were analyzed by using online Automatic Precise Positioning Service (APPS) to obtain the coordinates and covariance matrices. The results of the APPS were used in the deformation analysis. The detected points and true displaced points were compared with each other to obtain reliability of the method. According to the results, the analysis still detect stable points as displaced points. For the next step, we are going to search the reason of the wrong results and deal with acquiring more reliable results.

  7. Performance Analysis of Several GPS/Galileo Precise Point Positioning Models

    PubMed Central

    Afifi, Akram; El-Rabbany, Ahmed

    2015-01-01

    This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada’s GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference. PMID:26102495

  8. Performance Analysis of Several GPS/Galileo Precise Point Positioning Models.

    PubMed

    Afifi, Akram; El-Rabbany, Ahmed

    2015-06-19

    This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada's GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference.

  9. Precise definitions of some terminology for longitudinal clinical trials: subjects, patient populations, analysis sets, intention to treat, and related terms.

    PubMed

    Helms, Ronald W

    2016-11-01

    Biostatisticians recognize the importance of precise definitions of technical terms in randomized controlled clinical trial (RCCT) protocols, statistical analysis plans, and so on, in part because definitions are a foundation for subsequent actions. Imprecise definitions can be a source of controversies about appropriate statistical methods, interpretation of results, and extrapolations to larger populations. This paper presents precise definitions of some familiar terms and definitions of some new terms, some perhaps controversial. The glossary contains definitions that can be copied into a protocol, statistical analysis plan, or similar document and customized. The definitions were motivated and illustrated in the context of a longitudinal RCCT in which some randomized enrollees are non-adherent, receive a corrupted treatment, or withdraw prematurely. The definitions can be adapted for use in a much wider set of RCCTs. New terms can be used in place of controversial terms, for example, subject. We define terms specifying a person's progress through RCCT phases and that precisely define the RCCT's phases and milestones. We define terms that distinguish between subsets of an RCCT's enrollees and a much larger patient population. 'The intention-to-treat (ITT) principle' has multiple interpretations that can be distilled to the definitions of the 'ITT analysis set of randomized enrollees'. Most differences among interpretations of 'the' ITT principle stem from an RCCT's primary objective (mainly efficacy versus effectiveness). Four different 'authoritative' definitions of ITT analysis set of randomized enrollees illustrate the variety of interpretations. We propose a separate specification of the analysis set of data that will be used in a specific analysis. Copyright © 2016 John Wiley & Sons, Ltd.

  10. First high-precision differential abundance analysis of extremely metal-poor stars

    NASA Astrophysics Data System (ADS)

    Reggiani, Henrique; Meléndez, Jorge; Yong, David; Ramírez, Ivan; Asplund, Martin

    2016-02-01

    Context. Studies of extremely metal-poor stars indicate that chemical abundance ratios [X/Fe] have a root mean square scatter as low as 0.05 dex (12%). It remains unclear whether this reflects observational uncertainties or intrinsic astrophysical scatter arising from physical conditions in the interstellar medium at early times. Aims: We measure differential chemical abundance ratios in extremely metal-poor stars to investigate the limits of precision and to understand whether cosmic scatter or observational errors are dominant. Methods: We used high-resolution (R ~ 95 000) and high signal-to-noise (S/N = 700 at 5000 Å) HIRES/Keck spectra to determine high-precision differential abundances between two extremely metal-poor stars through a line-by-line differential approach. We determined stellar parameters for the star G64-37 with respect to the standard star G64-12. We performed EW measurements for the two stars for the lines recognized in both stars and performed spectral synthesis to study the carbon abundances. Results: The differential approach allowed us to obtain errors of σ(Teff) = 27 K, σ(log g) = 0.06 dex, σ( [Fe/H] ) = 0.02 dex and σ(vt) = 0.06 km s-1. We estimated relative chemical abundances with a precision as low as σ([X/Fe]) ≈ 0.01 dex. The small uncertainties demonstrate that there are genuine abundance differences larger than the measurement errors. The observed Li difference cannot be explained by the difference in mass because the less massive star has more Li. Conclusions: It is possible to achieve an abundance precision around ≈ 0.01-0.05 dex for extremely metal-poor stars, which opens new windows on the study of the early chemical evolution of the Galaxy. Table A.1 is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A67

  11. Minimal important change (MIC) based on a predictive modeling approach was more precise than MIC based on ROC analysis.

    PubMed

    Terluin, Berend; Eekhout, Iris; Terwee, Caroline B; de Vet, Henrica C W

    2015-12-01

    To present a new method to estimate a "minimal important change" (MIC) of health-related quality of life (HRQOL) scales, based on predictive modeling, and to compare its performance with the MIC based on receiver operating characteristic (ROC) analysis. To illustrate how the new method deals with variables that modify the MIC across subgroups. The new method uses logistic regression analysis and identifies the change score associated with a likelihood ratio of 1 as the MIC. Simulation studies were conducted to investigate under which distributional circumstances both methods produce concordant or discordant results and whether the methods differ in accuracy and precision. The "predictive MIC" and the ROC-based MIC were identical when the variances of the change scores in the improved and not-improved groups were equal and the distributions were normal or oppositely skewed. The predictive MIC turned out to be more precise than the ROC-based MIC. The predictive MIC allowed for the testing and estimation of modifying factors such as baseline severity. In many situations, the newly described MIC based on predictive modeling yields the same value as the ROC-based MIC but with significantly greater precision. This advantage translates to increased statistical power in MIC studies. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Analysis of the Murine Immune Response to Pulmonary Delivery of Precisely Fabricated Nano- and Microscale Particles

    PubMed Central

    Roberts, Reid A.; Shen, Tammy; Allen, Irving C.; Hasan, Warefta; DeSimone, Joseph M.; Ting, Jenny P. Y.

    2013-01-01

    Nanomedicine has the potential to transform clinical care in the 21st century. However, a precise understanding of how nanomaterial design parameters such as size, shape and composition affect the mammalian immune system is a prerequisite for the realization of nanomedicine's translational promise. Herein, we make use of the recently developed Particle Replication in Non-wetting Template (PRINT) fabrication process to precisely fabricate particles across and the nano- and micro-scale with defined shapes and compositions to address the role of particle design parameters on the murine innate immune response in both in vitro and in vivo settings. We find that particles composed of either the biodegradable polymer poly(lactic-co-glycolic acid) (PLGA) or the biocompatible polymer polyethylene glycol (PEG) do not cause release of pro-inflammatory cytokines nor inflammasome activation in bone marrow-derived macrophages. When instilled into the lungs of mice, particle composition and size can augment the number and type of innate immune cells recruited to the lungs without triggering inflammatory responses as assayed by cytokine release and histopathology. Smaller particles (80×320 nm) are more readily taken up in vivo by monocytes and macrophages than larger particles (6 µm diameter), yet particles of all tested sizes remained in the lungs for up to 7 days without clearance or triggering of host immunity. These results suggest rational design of nanoparticle physical parameters can be used for sustained and localized delivery of therapeutics to the lungs. PMID:23593509

  13. Detailed seismotectonic analysis of Sumatra subduction zone revealed by high precision earthquake location

    NASA Astrophysics Data System (ADS)

    Sagala, Ricardo Alfencius; Harjadi, P. J. Prih; Heryandoko, Nova; Sianipar, Dimas

    2017-07-01

    Sumatra was one of the most high seismicity regions in Indonesia. The subduction of Indo-Australian plate beneath Eurasian plate in western Sumatra contributes for many significant earthquakes that occur in this area. These earthquake events can be used to analyze the seismotectonic of Sumatra subduction zone and its system. In this study we use teleseismic double-difference method to obtain more high precision earthquake distribution in Sumatra subduction zone. We use a 3D nested regional-global velocity model. We use a combination of data from both of ISC (International Seismological Center) and BMKG (Agency for Meteorology Climatology and Geophysics, Indonesia). We successfully relocate about 6886 earthquakes that occur on period of 1981-2015. We consider that this new location is more precise than the regular bulletin. The relocation results show greatly reduced of RMS residual of travel time. Using this data, we can construct a new seismotectonic map of Sumatra. A well-built geometry of subduction slab, faults and volcano arc can be obtained from the new bulletin. It is also showed that at a depth of 140-170 km, there is many events occur as moderate-to-deep earthquakes, and we consider about the relation of the slab's events with volcanic arc and inland fault system. A reliable slab model is also built from regression equation using new relocated data. We also analyze the spatial-temporal of seismotectonic using b-value mapping that inspected in detail horizontally and vertically cross-section.

  14. High precision carbon-interspaced antiscatter grids: Performance testing and moiré pattern analysis

    NASA Astrophysics Data System (ADS)

    Lee, S. J.; Cho, H. S.; Oh, J. E.; Choi, S. I.; Cho, H. M.; Park, Y. O.; Hong, D. K.; Lee, M. S.; Yang, Y. J.; Je, U. K.; Kim, D. S.; Lee, H. K.

    2011-10-01

    Recently, we have developed high precision carbon-interspaced antiscatter grids to be suitable for digital radiography (DR) adopting a precise sawing process. For systematic evaluation of the grid performance, we prepared several sample grids having different grid frequencies (4.0-8.5 lines/mm) and grid ratios (5:1-10:1) and established a well-controlled test condition based upon the IEC standard. In this paper, we presented the performance characteristics of the carbon-interspaced grids in terms of the transmission of primary radiation ( Tp), the transmission of scattered radiation ( Ts), the transmission of total radiation ( Tt), contrast improvement factor ( Cif), and Bucky factor ( B). We also described the grid line artifact, known as a moiré pattern, which may be the most critical problem to be solved for the successful grid use in DR. We examined the factors that affect the moiré pattern by integrating the sample grids with an a-Se based flat panel detector having a 139 μm×139 μm pixel size.

  15. In-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

    SciTech Connect

    Piscotty, M.A.; Davis, P.J.; Saito, T.T.; Blaedel, K.L.; Griffith, L.

    1997-08-01

    The demand and use of precision grinding of structural ceramics continue to increase as the worldwide advanced ceramic industry surpasses $20 billion is sales. Included in this industry are engineering structural ceramics, electronic ceramics, bioceramics and others. These materials are used in applications such as engine components, casting and extrusion dies, bearings, medical implants, nozzles, thermal insulators, and more. Along with the variety of ceramic applications comes a broad range of precision requirements, which in turn leads to various required processes to accommodate a spectrum of specifications. A process for grinding ceramic components to micrometer tolerances was employed and further developed at Lawrence Livermore National Laboratory for two separate grinding projects.

  16. Molecular and Functional Analyses of a Maize Autoactive NB-LRR Protein Identify Precise Structural Requirements for Activity

    PubMed Central

    Wang, Guan-Feng; Ji, Jiabing; EI-Kasmi, Farid; Dangl, Jeffery L.; Johal, Guri; Balint-Kurti, Peter J.

    2015-01-01

    Plant disease resistance is often mediated by nucleotide binding-leucine rich repeat (NLR) proteins which remain auto-inhibited until recognition of specific pathogen-derived molecules causes their activation, triggering a rapid, localized cell death called a hypersensitive response (HR). Three domains are recognized in one of the major classes of NLR proteins: a coiled-coil (CC), a nucleotide binding (NB-ARC) and a leucine rich repeat (LRR) domains. The maize NLR gene Rp1-D21 derives from an intergenic recombination event between two NLR genes, Rp1-D and Rp1-dp2 and confers an autoactive HR. We report systematic structural and functional analyses of Rp1 proteins in maize and N. benthamiana to characterize the molecular mechanism of NLR activation/auto-inhibition. We derive a model comprising the following three main features: Rp1 proteins appear to self-associate to become competent for activity. The CC domain is signaling-competent and is sufficient to induce HR. This can be suppressed by the NB-ARC domain through direct interaction. In autoactive proteins, the interaction of the LRR domain with the NB-ARC domain causes de-repression and thus disrupts the inhibition of HR. Further, we identify specific amino acids and combinations thereof that are important for the auto-inhibition/activity of Rp1 proteins. We also provide evidence for the function of MHD2, a previously uncharacterized, though widely conserved NLR motif. This work reports several novel insights into the precise structural requirement for NLR function and informs efforts towards utilizing these proteins for engineering disease resistance. PMID:25719542

  17. Structural Analysis of Fungal Cerebrosides

    PubMed Central

    Barreto-Bergter, Eliana; Sassaki, Guilherme L.; de Souza, Lauro M.

    2011-01-01

    Of the ceramide monohexosides (CMHs), gluco- and galactosyl-ceramides are the main neutral glycosphingolipids expressed in fungal cells. Their structural determination is greatly dependent on the use of mass spectrometric techniques, including fast atom bombardment-mass spectrometry, electrospray ionization, and energy collision-induced dissociation mass spectrometry. Nuclear magnetic resonance has also been used successfully. Such a combination of techniques, combined with classical analytical separation, such as high-performance thin layer chromatography and column chromatography, has led to the structural elucidation of a great number of fungal CMHs. The structure of fungal CMH is conserved among fungal species and consists of a glucose or galactose residue attached to a ceramide moiety containing 9-methyl-4,8-sphingadienine with an amidic linkage to hydroxylated fatty acids, most commonly having 16 or 18 carbon atoms and unsaturation between C-3 and C-4. Along with their unique structural characteristics, fungal CMHs have a peculiar subcellular distribution and striking biological properties. Fungal cerebrosides were also characterized as antigenic molecules directly or indirectly involved in cell growth or differentiation in Schizophyllum commune, Cryptococcus neoformans, Pseudallescheria boydii, Candida albicans, Aspergillus nidulans, Aspergillus fumigatus, and Colletotrichum gloeosporioides. Besides classical techniques for cerebroside (CMH) analysis, we now describe new approaches, combining conventional thin layer chromatography and mass spectrometry, as well as emerging technologies for subcellular localization and distribution of glycosphingolipids by secondary ion mass spectrometry and imaging matrix-assisted laser desorption ionization time-of-flight. PMID:22164155

  18. High Precision Analysis of Translational Pausing by Ribosome Profiling in Bacteria Lacking EFP

    PubMed Central

    Woolstenhulme, Christopher J.; Guydosh, Nicholas R.; Green, Rachel; Buskirk, Allen R.

    2015-01-01

    Summary Ribosome profiling is a powerful method for globally assessing the activity of ribosomes in a cell. Despite its application in many organisms, ribosome profiling studies in bacteria have struggled to obtain the resolution necessary to precisely define translational pauses. Here we report improvements that yield much higher resolution in E. coli profiling data, enabling us to more accurately assess ribosome pausing and refine earlier studies of the impact of polyproline motifs on elongation. We comprehensively characterize pausing at proline-rich motifs in the absence of elongation factor EFP. We find that only a small fraction of genes with strong pausing motifs have reduced ribosome density downstream and identify features that explain this phenomenon. These features allow us to predict which proteins likely have reduced output in the efp knockout strain. PMID:25843707

  19. An analysis of the double-precision floating-point FFT on FPGAs.

    SciTech Connect

    Hemmert, K. Scott; Underwood, Keith Douglas

    2005-01-01

    Advances in FPGA technology have led to dramatic improvements in double precision floating-point performance. Modern FPGAs boast several GigaFLOPs of raw computing power. Unfortunately, this computing power is distributed across 30 floating-point units with over 10 cycles of latency each. The user must find two orders of magnitude more parallelism than is typically exploited in a single microprocessor; thus, it is not clear that the computational power of FPGAs can be exploited across a wide range of algorithms. This paper explores three implementation alternatives for the fast Fourier transform (FFT) on FPGAs. The algorithms are compared in terms of sustained performance and memory requirements for various FFT sizes and FPGA sizes. The results indicate that FPGAs are competitive with microprocessors in terms of performance and that the 'correct' FFT implementation varies based on the size of the transform and the size of the FPGA.

  20. Estimated results analysis and application of the precise point positioning based high-accuracy ionosphere delay

    NASA Astrophysics Data System (ADS)

    Wang, Shi-tai; Peng, Jun-huan

    2015-12-01

    The characterization of ionosphere delay estimated with precise point positioning is analyzed in this paper. The estimation, interpolation and application of the ionosphere delay are studied based on the processing of 24-h data from 5 observation stations. The results show that the estimated ionosphere delay is affected by the hardware delay bias from receiver so that there is a difference between the estimated and interpolated results. The results also show that the RMSs (root mean squares) are bigger, while the STDs (standard deviations) are better than 0.11 m. When the satellite difference is used, the hardware delay bias can be canceled. The interpolated satellite-differenced ionosphere delay is better than 0.11 m. Although there is a difference between the between the estimated and interpolated ionosphere delay results it cannot affect its application in single-frequency positioning and the positioning accuracy can reach cm level.

  1. Functional Generalized Structured Component Analysis.

    PubMed

    Suk, Hye Won; Hwang, Heungsun

    2016-12-01

    An extension of Generalized Structured Component Analysis (GSCA), called Functional GSCA, is proposed to analyze functional data that are considered to arise from an underlying smooth curve varying over time or other continua. GSCA has been geared for the analysis of multivariate data. Accordingly, it cannot deal with functional data that often involve different measurement occasions across participants and a large number of measurement occasions that exceed the number of participants. Functional GSCA addresses these issues by integrating GSCA with spline basis function expansions that represent infinite-dimensional curves onto a finite-dimensional space. For parameter estimation, functional GSCA minimizes a penalized least squares criterion by using an alternating penalized least squares estimation algorithm. The usefulness of functional GSCA is illustrated with gait data.

  2. Use of in-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

    SciTech Connect

    Piscotty, M. A., LLNL

    1997-08-01

    This paper presents recent work performed at Lawrence Livermore National Laboratory to develop cost-effective, versatile and robust manufacturing methods for grinding precision features in structural ceramics using metal-bond, superabrasive grinding wheels. The developed processes include utilizing specialized, on-machine hardware to generate precision profiles onto grinding wheels using electrical-discharge machining (EDM) and a contoured rotating electrode. The production grinding processes are described, which were developed and used to grind various precision details into a host of structural ceramics such as Al{sub 2}O{sub 3}, Si{sub 3}N{sub 4}, and BeO. The methodologies, hardware and results of both creep-feed and cylindrical grinding are described. A discussion of imparted grinding damage and wheel wear is also presented.

  3. Bias, precision and statistical power of analysis of covariance in the analysis of randomized trials with baseline imbalance: a simulation study

    PubMed Central

    2014-01-01

    Background Analysis of variance (ANOVA), change-score analysis (CSA) and analysis of covariance (ANCOVA) respond differently to baseline imbalance in randomized controlled trials. However, no empirical studies appear to have quantified the differential bias and precision of estimates derived from these methods of analysis, and their relative statistical power, in relation to combinations of levels of key trial characteristics. This simulation study therefore examined the relative bias, precision and statistical power of these three analyses using simulated trial data. Methods 126 hypothetical trial scenarios were evaluated (126 000 datasets), each with continuous data simulated by using a combination of levels of: treatment effect; pretest-posttest correlation; direction and magnitude of baseline imbalance. The bias, precision and power of each method of analysis were calculated for each scenario. Results Compared to the unbiased estimates produced by ANCOVA, both ANOVA and CSA are subject to bias, in relation to pretest-posttest correlation and the direction of baseline imbalance. Additionally, ANOVA and CSA are less precise than ANCOVA, especially when pretest-posttest correlation ≥ 0.3. When groups are balanced at baseline, ANCOVA is at least as powerful as the other analyses. Apparently greater power of ANOVA and CSA at certain imbalances is achieved in respect of a biased treatment effect. Conclusions Across a range of correlations between pre- and post-treatment scores and at varying levels and direction of baseline imbalance, ANCOVA remains the optimum statistical method for the analysis of continuous outcomes in RCTs, in terms of bias, precision and statistical power. PMID:24712304

  4. Minimally invasive measurement of cardiac output during surgery and critical care: a meta-analysis of accuracy and precision.

    PubMed

    Peyton, Philip J; Chong, Simon W

    2010-11-01

    When assessing the accuracy and precision of a new technique for cardiac output measurement, the commonly quoted criterion for acceptability of agreement with a reference standard is that the percentage error (95% limits of agreement/mean cardiac output) should be 30% or less. We reviewed published data on four different minimally invasive methods adapted for use during surgery and critical care: pulse contour techniques, esophageal Doppler, partial carbon dioxide rebreathing, and transthoracic bioimpedance, to assess their bias, precision, and percentage error in agreement with thermodilution. An English language literature search identified published papers since 2000 which examined the agreement in adult patients between bolus thermodilution and each method. For each method a meta-analysis was done using studies in which the first measurement point for each patient could be identified, to obtain a pooled mean bias, precision, and percentage error weighted according to the number of measurements in each study. Forty-seven studies were identified as suitable for inclusion: N studies, n measurements: mean weighted bias [precision, percentage error] were: pulse contour N = 24, n = 714: -0.00 l/min [1.22 l/min, 41.3%]; esophageal Doppler N = 2, n = 57: -0.77 l/min [1.07 l/min, 42.1%]; partial carbon dioxide rebreathing N = 8, n = 167: -0.05 l/min [1.12 l/min, 44.5%]; transthoracic bioimpedance N = 13, n = 435: -0.10 l/min [1.14 l/min, 42.9%]. None of the four methods has achieved agreement with bolus thermodilution which meets the expected 30% limits. The relevance in clinical practice of these arbitrary limits should be reassessed.

  5. Precision metrology.

    PubMed

    Jiang, X; Whitehouse, D J

    2012-08-28

    This article is a summary of the Satellite Meeting, which followed on from the Discussion Meeting at the Royal Society on 'Ultra-precision engineering: from physics to manufacture', held at the Kavli Royal Society International Centre, Chicheley Hall, Buckinghamshire, UK. The meeting was restricted to 18 invited experts in various aspects of precision metrology from academics from the UK and Sweden, Government Institutes from the UK and Germany and global aerospace industries. It examined and identified metrology problem areas that are, or may be, limiting future developments in precision engineering and, in particular, metrology. The Satellite Meeting was intended to produce a vision that will inspire academia and industry to address the solutions of those open-ended problems identified. The discussion covered three areas, namely the function of engineering parts, their measurement and their manufacture, as well as their interactions.

  6. A pilot study of contextual UMLS indexing to improve the precision of concept-based representation in XML-structured clinical radiology reports.

    PubMed

    Huang, Yang; Lowe, Henry J; Hersh, William R

    2003-01-01

    Despite the advantages of structured data entry, much of the patient record is still stored as unstructured or semistructured narrative text. The issue of representing clinical document content remains problematic. The authors' prior work using an automated UMLS document indexing system has been encouraging but has been affected by the generally low indexing precision of such systems. In an effort to improve precision, the authors have developed a context-sensitive document indexing model to calculate the optimal subset of UMLS source vocabularies used to index each document section. This pilot study was performed to evaluate the utility of this indexing approach on a set of clinical radiology reports. A set of clinical radiology reports that had been indexed manually using UMLS concept descriptors was indexed automatically by the SAPHIRE indexing engine. Using the data generated by this process the authors developed a system that simulated indexing, at the document section level, of the same document set using many permutations of a subset of the UMLS constituent vocabularies. The precision and recall scores generated by simulated indexing for each permutation of two or three UMLS constituent vocabularies were determined. While there was considerable variation in precision and recall values across the different subtypes of radiology reports, the overall effect of this indexing strategy using the best combination of two or three UMLS constituent vocabularies was an improvement in precision without significant impact of recall. In this pilot study a contextual indexing strategy improved overall precision in a set of clinical radiology reports.

  7. Precision Nutrition 4.0: A Big Data and Ethics Foresight Analysis--Convergence of Agrigenomics, Nutrigenomics, Nutriproteomics, and Nutrimetabolomics.

    PubMed

    Özdemir, Vural; Kolker, Eugene

    2016-02-01

    Nutrition is central to sustenance of good health, not to mention its role as a cultural object that brings together or draws lines among societies. Undoubtedly, understanding the future paths of nutrition science in the current era of Big Data remains firmly on science, technology, and innovation strategy agendas around the world. Nutrigenomics, the confluence of nutrition science with genomics, brought about a new focus on and legitimacy for "variability science" (i.e., the study of mechanisms of person-to-person and population differences in response to food, and the ways in which food variably impacts the host, for example, nutrient-related disease outcomes). Societal expectations, both public and private, and claims over genomics-guided and individually-tailored precision diets continue to proliferate. While the prospects of nutrition science, and nutrigenomics in particular, are established, there is a need to integrate the efforts in four Big Data domains that are naturally allied--agrigenomics, nutrigenomics, nutriproteomics, and nutrimetabolomics--that address complementary variability questions pertaining to individual differences in response to food-related environmental exposures. The joint use of these four omics knowledge domains, coined as Precision Nutrition 4.0 here, has sadly not been realized to date, but the potentials for such integrated knowledge innovation are enormous. Future personalized nutrition practices would benefit from a seamless planning of life sciences funding, research, and practice agendas from "farm to clinic to supermarket to society," and from "genome to proteome to metabolome." Hence, this innovation foresight analysis explains the already existing potentials waiting to be realized, and suggests ways forward for innovation in both technology and ethics foresight frames on precision nutrition. We propose the creation of a new Precision Nutrition Evidence Barometer for periodic, independent, and ongoing retrieval, screening

  8. Experimental and numerical analysis of thermal forming processes for precision optics

    NASA Astrophysics Data System (ADS)

    Su, Lijuan

    Glass has been fabricated into different optical elements including aspherical lenses and freeform mirrors. However, aspherical lenses are very difficult to manufacture using traditional methods since they were specially developed for spherical lenses. On the other hand, large size mirrors are also difficult to make especially for high precision applications or if designed with complicated shapes. Recently developed two closely related thermal forming processes, i.e. compression molding and thermal slumping, have emerged as two promising methods for manufacturing aspherical lenses and freeform mirrors efficiently. Compression molding has already been used in industry to fabricate consumer products such as the lenses for digital cameras, while thermal slumping has been aggressively tested to create x-ray mirrors for space-based telescopes as well as solar panels. Although both process showed great potentials, there are a quite few technical challenges that prevent them from being readily implemented in industry for high volume production. This dissertation research seeks a fundamental understanding of the thermal forming processes for both precision glass lenses and freeform mirrors by using a combined experimental, analytical and numerical modeling approach. First, a finite element method (FEM) based methodology was presented to predict the refractive index change of glass material occurred during cooling. The FEM prediction was then validated using experimental results. Second, experiments were also conducted on glass samples with different cooling rates to study the refractive index variation caused by non-uniform cooling. A Shack-Hartmann Sensor (SHS) test setup was built to measure the index variations of thermally treated glass samples. Again, an FEM simulation model was developed to predict the refractive index variation. The prediction was compared with the experimental result, and the effects of different parameters were evaluated. In the last phase of this

  9. Autocorrelation analysis of bone structure.

    PubMed

    Rotter, M; Berg, A; Langenberger, H; Grampp, S; Imhof, H; Moser, E

    2001-07-01

    We propose a method called spatial autocorrelation analysis (SACA) to determine the spatial anisotropy of the trabecular bone in order to investigate osteoporosis. For demonstrating the potential of SACA we first evaluate the method on rectangular, simulated test patterns as a simple model for the anisotropic pore structure of the bone. As a next step towards biomedical application, photographic reference images of human vertebral bone were investigated by SACA. Osteoporotic bone structure could be clearly differentiated from non-osteoporotic sample images. Moreover, for demonstration of the applicability and potential of the method for in vivo characterization of osteoporosis, the microstructure of the human calcaneus was investigated by MR-microimaging on a young healthy male subject and an osteoporotic female. The measurements were performed using a high-field (3T) whole-body MR tomograph equipped with a special, strong head gradient system. The signal was acquired with a surface coil mounted on an in-house-built device for convenient immobilization of the subject's foot. Using a 3D gradient echo sequence a resolution of 0.254 x 0.254 x 2.188 mm3 was achieved in vivo. Selected images were inverted, gradient corrected for the inhomogeneous but sensitive detection by the surface coil, and subsequently analyzed by SACA. The anisotropy of bone structure detected by SACA is a possible candidate for noninvasive determination of the osteoporotic status, potentially complementing standard bone mineral density measurements. Copyright 2001 Wiley-Liss, Inc.

  10. XRF in waste glass analysis and vitrification process control, Part 1: Sample preparation and measurement precision

    SciTech Connect

    Resce, J.L.; Ragsdale, R.G.; Overcamp, T.J.; Jurgensen, A.; Cicero, C.; Bickford, D.F.

    1994-12-31

    The analysis of several waste glasses has been carried out by X-ray fluorescence (XRF) spectrometry in an attempt to develop a simple, rapid, and consistent procedure for specimen preparation. Glass disk specimens, suitable for XRF analysis, can be prepared by casting the melt directly into a preheated graphite mold followed by annealing for 30 minutes at 500{degrees}C. With this technique specimens could be available for analysis within 45 minutes. Element x-ray intensities, measured from replicate specimens, were found to be highly reproducible, with relative standard deviations typically less than one percent. This XRF analysis is much more rapid and may afford greater accuracy than conventional wet chemical techniques in waste glass analysis. Furthermore, this XRF analysis may be used in vitrification process control by permitting on-site monitoring of glass composition. A product control strategy is discussed.

  11. Corneal astigmatism analysis for toric intraocular lens implantation: precise measurements for perfect correction.

    PubMed

    Lee, Hun; Kim, Tae-Im; Kim, Eung Kweon

    2015-01-01

    Corneal astigmatism is a common refractive error observed in a significant percentage of cataract patients. Accurate measurements of the preexisting corneal astigmatism are essential in order to achieve the desired refractive outcome after toric intraocular lens (IOL) implantation. This article presents a comprehensive review of recent published literatures on methods for measuring preoperative corneal astigmatism for toric IOL implantation. A variety of instruments has been introduced and used to measure the magnitude and meridian of corneal astigmatism during preoperative assessments of cataract patients. Instruments that consider both the anterior and posterior corneal surfaces as critical factors for measuring total corneal astigmatism are expected to provide better accuracy. Although these instruments facilitate improved evaluations of corneal astigmatism and have helped minimize postoperative residual astigmatism, a perfect method to analyze preoperative corneal astigmatism has not yet been established. Perfect correction of astigmatism after toric IOL implantation by using accurate corneal astigmatism values is the goal of this surgical procedure. To achieve this, correct and precise measurements of corneal astigmatism to determine the magnitude and meridian should be obtained.

  12. A combined MR and CT study for precise quantitative analysis of the avian brain

    NASA Astrophysics Data System (ADS)

    Jirak, Daniel; Janacek, Jiri; Kear, Benjamin P.

    2015-10-01

    Brain size is widely used as a measure of behavioural complexity and sensory-locomotive capacity in avians but has largely relied upon laborious dissections, endoneurocranial tissue displacement, and physical measurement to derive comparative volumes. As an alternative, we present a new precise calculation method based upon coupled magnetic resonance (MR) imaging and computed tomography (CT). Our approach utilizes a novel interactive Fakir probe cross-referenced with an automated CT protocol to efficiently generate total volumes and surface areas of the brain tissue and endoneurocranial space, as well as the discrete cephalic compartments. We also complemented our procedures by using sodium polytungstate (SPT) as a contrast agent. This greatly enhanced CT applications but did not degrade MR quality and is therefore practical for virtual brain tissue reconstructions employing multiple imaging modalities. To demonstrate our technique, we visualized sex-based brain size differentiation in a sample set of Ring-necked pheasants (Phasianus colchicus). This revealed no significant variance in relative volume or surface areas of the primary brain regions. Rather, a trend towards isometric enlargement of the total brain and endoneurocranial space was evidenced in males versus females, thus advocating a non-differential sexually dimorphic pattern of brain size increase amongst these facultatively flying birds.

  13. A combined MR and CT study for precise quantitative analysis of the avian brain

    PubMed Central

    Jirak, Daniel; Janacek, Jiri; Kear, Benjamin P.

    2015-01-01

    Brain size is widely used as a measure of behavioural complexity and sensory-locomotive capacity in avians but has largely relied upon laborious dissections, endoneurocranial tissue displacement, and physical measurement to derive comparative volumes. As an alternative, we present a new precise calculation method based upon coupled magnetic resonance (MR) imaging and computed tomography (CT). Our approach utilizes a novel interactive Fakir probe cross-referenced with an automated CT protocol to efficiently generate total volumes and surface areas of the brain tissue and endoneurocranial space, as well as the discrete cephalic compartments. We also complemented our procedures by using sodium polytungstate (SPT) as a contrast agent. This greatly enhanced CT applications but did not degrade MR quality and is therefore practical for virtual brain tissue reconstructions employing multiple imaging modalities. To demonstrate our technique, we visualized sex-based brain size differentiation in a sample set of Ring-necked pheasants (Phasianus colchicus). This revealed no significant variance in relative volume or surface areas of the primary brain regions. Rather, a trend towards isometric enlargement of the total brain and endoneurocranial space was evidenced in males versus females, thus advocating a non-differential sexually dimorphic pattern of brain size increase amongst these facultatively flying birds. PMID:26515262

  14. Multiscale Modeling and Analysis of an Ultra-Precision Damage Free Machining Method

    NASA Astrophysics Data System (ADS)

    Guan, Chaoliang; Peng, Wenqiang

    2016-06-01

    Under the condition of high laser flux, laser induced damage of optical element does not occur is the key to success of laser fusion ignition system. US government survey showed that the processing defects caused the laser induced damage threshold (LIDT) to decrease is one of the three major challenges. Cracks and scratches caused by brittle and plastic removal machining are fatal flaws. Using hydrodynamic effect polishing method can obtain damage free surface on quartz glass. The material removal mechanism of this typical ultra-precision machining process was modeled in multiscale. In atomic scale, chemical modeling illustrated the weakening and breaking of chemical bond energy. In particle scale, micro contact modeling given the elastic remove mode boundary of materials. In slurry scale, hydrodynamic flow modeling showed the dynamic pressure and shear stress distribution which are relations with machining effect. Experiment was conducted on a numerically controlled system, and one quartz glass optical component was polished in the elastic mode. Results show that the damages are removed away layer by layer as the removal depth increases due to the high damage free machining ability of the HEP. And the LIDT of sample was greatly improved.

  15. Accuracy Analysis of Precise Point Positioning of Compass Navigation System Applied to Crustal Motion Monitoring

    NASA Astrophysics Data System (ADS)

    Wang, Yuebing

    2017-04-01

    Based on the observation data of Compass/GPSobserved at five stations, time span from July 1, 2014 to June 30, 2016. UsingPPP positioning model of the PANDA software developed by Wuhan University,Analyzedthe positioning accuracy of single system and Compass/GPS integrated resolving, and discussed the capability of Compass navigation system in crustal motion monitoring. The results showed that the positioning accuracy in the east-west directionof the Compass navigation system is lower than the north-south direction (the positioning accuracy de 3 times RMS), in general, the positioning accuracyin the horizontal direction is about 1 2cm and the vertical direction is about 5 6cm. The GPS positioning accuracy in the horizontal direction is better than 1cm and the vertical direction is about 1 2cm. The accuracy of Compass/GPS integrated resolving is quite to GPS. It is worth mentioning that although Compass navigation system precision point positioning accuracy is lower than GPS, two sets of velocity fields obtained by using the Nikolaidis (2002) model to analyze the Compass and GPS time series results respectively, the results showed that the maximum difference of the two sets of velocity field in horizontal directions is 1.8mm/a. The Compass navigation system can now be used to monitor the crustal movement of the large deformation area, based on the velocity field in horizontal direction.

  16. Measures of precision for dissimilarity-based multivariate analysis of ecological communities.

    PubMed

    Anderson, Marti J; Santana-Garcon, Julia

    2015-01-01

    Ecological studies require key decisions regarding the appropriate size and number of sampling units. No methods currently exist to measure precision for multivariate assemblage data when dissimilarity-based analyses are intended to follow. Here, we propose a pseudo multivariate dissimilarity-based standard error (MultSE) as a useful quantity for assessing sample-size adequacy in studies of ecological communities. Based on sums of squared dissimilarities, MultSE measures variability in the position of the centroid in the space of a chosen dissimilarity measure under repeated sampling for a given sample size. We describe a novel double resampling method to quantify uncertainty in MultSE values with increasing sample size. For more complex designs, values of MultSE can be calculated from the pseudo residual mean square of a permanova model, with the double resampling done within appropriate cells in the design. R code functions for implementing these techniques, along with ecological examples, are provided. © 2014 The Authors. Ecology Letters published by John Wiley & Sons Ltd and CNRS.

  17. Parameter Analysis of Lunar Surface Navigation Utilizing Dilution-of-Precision Methodology With Lunar Orbiters

    NASA Technical Reports Server (NTRS)

    Welch, Bryan W.

    2008-01-01

    With the NASA Vision for Space Exploration focusing on the return of astronauts to the Moon and eventually to Mars, architectures for new navigation concepts must be derived and analyzed. One such concept, developed by the Space Communications Architecture Working Group (SCAWG), is to place a constellation of satellites around the Moon. Previously completed analyses examined the performance of multiple satellite constellations and recommended a constellation oriented as a Walker polar 6/2/1 with a semimajor axis (SMA) of 9250 km. One requirement of the constellations that were examined was that they have continuous access to any location on the lunar surface. In this report, the polar 6/2/1 and polar 8/2/1, with equal SMAs, are examined in greater detail. The dilution-of-precision (DoP) methodology is utilized to examine the effects of longitude surface points, latitude surface points, elevation requirements, and modified failure modes for these two constellations with regard to system availability. Longitude study results show that points along a meridian closely approximate the results of a global set of data points. Latitude study results show that previous assumptions with regard to latitude spacing are adequate to simulate global system availability. Elevation study results show that global system availability curves follow a reverse sigmoid function. Modified failure mode study results show that the benefits of reorienting a failure mode constellation depend on the type of navigation system and the length of the integration period being used.

  18. Self-centering fiber alignment structures for high-precision field installable single-mode fiber connectors

    NASA Astrophysics Data System (ADS)

    Van Erps, Jürgen; Ebraert, Evert; Gao, Fei; Vervaeke, Michael; Berghmans, Francis; Beri, Stefano; Watté, Jan; Thienpont, Hugo

    2014-05-01

    There is a steady increase in the demand for internet bandwidth, primarily driven by cloud services and high-definition video streaming. Europe's Digital Agenda states the ambitious objective that by 2020 all Europeans should have access to internet at speeds of 30Mb/s or above, with 50% or more of households subscribing to connections of 100Mb/s. Today however, internet access in Europe is mainly based on the first generation of broadband, meaning internet accessed over legacy telephone copper and TV cable networks. In recent years, Fiber-To-The-Home (FTTH) networks have been adopted as a replacement of traditional electrical connections for the `last mile' transmission of information at bandwidths over 1Gb/s. However, FTTH penetration is still very low (< 5%) in most major Western economies. The main reason for this is the high deployment cost of FTTH networks. Indeed, the success and adoption of optical access networks critically depend on the quality and reliability of connections between optical fibers. In particular a further reduction of insertion loss of field- installable connectors must be achieved without a significant increase in component cost. This requires precise alignment of fibers that can differ in terms of ellipticity, eccentricity or diameter and seems hardly achievable using today's widespread ferrule-based alignment systems. In this paper, we present a field-installable connector based on deflectable/compressible spring structures, providing a self-centering functionality for the fiber. This way, it can accommodate for possible fiber cladding diameter variations (the tolerance on the cladding diameter of G.652 fiber is typically +/-0.7μm). The mechanical properties of the cantilever are derived through an analytical approximation and a mathematical model of the spring constant, and finite element-based simulations are carried out to find the maximum first principal stress as well as the stress distribution distribution in the fiber alignment

  19. Wavelength Selection Method Based on Differential Evolution for Precise Quantitative Analysis Using Terahertz Time-Domain Spectroscopy.

    PubMed

    Li, Zhi; Chen, Weidong; Lian, Feiyu; Ge, Hongyi; Guan, Aihong

    2017-01-01

    Quantitative analysis of component mixtures is an important application of terahertz time-domain spectroscopy (THz-TDS) and has attracted broad interest in recent research. Although the accuracy of quantitative analysis using THz-TDS is affected by a host of factors, wavelength selection from the sample's THz absorption spectrum is the most crucial component. The raw spectrum consists of signals from the sample and scattering and other random disturbances that can critically influence the quantitative accuracy. For precise quantitative analysis using THz-TDS, the signal from the sample needs to be retained while the scattering and other noise sources are eliminated. In this paper, a novel wavelength selection method based on differential evolution (DE) is investigated. By performing quantitative experiments on a series of binary amino acid mixtures using THz-TDS, we demonstrate the efficacy of the DE-based wavelength selection method, which yields an error rate below 5%.

  20. Progress in thermostructural analysis of space structures

    NASA Technical Reports Server (NTRS)

    Thornton, E. A.; Dechaumphai, P.; Mahaney, J.; Pandey, A. K.

    1982-01-01

    A finite element space structures research focused on the interdisciplinary problems of heating, thermal, and structural analysis is discussed. Slender member shadowing effects, and cable stiffened structures are described.

  1. Composition of structural carbohydrates in biomass: precision of a liquid chromatography method using a neutral detergent extraction and a charged aerosol detector.

    PubMed

    Godin, Bruno; Agneessens, Richard; Gerin, Patrick A; Delcarte, Jérôme

    2011-09-30

    We adapted and optimized a method to quantify the cellulose, hemicellulose, xylan, arabinan, mannan, galactan contents in lignocellulosic biomass. This method is based on a neutral detergent extraction (NDE) of the interfering biomass components, followed by a sulfuric acid hydrolysis (SAH) of the structural polysaccharides, and a liquid chromatography with charged aerosol detection (LC-CAD) to analyze the released monosaccharides. The first step of this NDE-SAH-LC-CAD method aims at removing all compounds that interfere with the subsequent sulphuric acid hydrolysis or with the subsequent chromatographic quantification of the cellulosic and hemicellulosic monosaccharides. This step includes starch hydrolysis with an analytical thermostable α-amylase followed by an extraction of soluble compounds by a Van Soest neutral detergent solution (NDE). The aim of this paper was to assess the precision of this method when choosing fiber sorghum (Sorghum bicolor (L.) Moench), tall fescue (Festuca arundinacea Schreb.) and fiber hemp (Cannabis sativa L.) as representative lignocellulosic biomass. The cellulose content of fiber sorghum, tall fescue and fiber hemp determined by the NDE-SAH-LC-CAD method were 28.7 ± 1.0, 29.7 ± 1.0 and 43.6 ± 1.2g/100g dry matter, respectively, and their hemicellulose content were 18.6 ± 0.5, 16.5 ± 0.5 and 14.5 ± 0.2g/100g dry matter, respectively. Cellulose, mannan and galactan contents were higher in fiber hemp (dicotyledon) as compared to tall fescue and fiber sorghum (monocotyledons). The xylan, arabinan and total hemicellulose contents were higher in tall fescue and fiber sorghum as compared to fiber hemp. The precision of the NDE-SAH-LC-CAD method was better for polysaccharide concentration levels above 1g/100g dry matter. Galactan analysis offered a lower precision, due to a lower CAD response intensity to galactose as compared to the other monosaccharides. The dispersions of the results (expanded uncertainty) of the NDE

  2. Precise Analysis of Microstructural Effects on Mechanical Properties of Cast ADC12 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Okayasu, Mitsuhiro; Takeuchi, Shuhei; Yamamoto, Masaki; Ohfuji, Hiroaki; Ochi, Toshihiro

    2015-04-01

    The effects of microstructural characteristics (secondary dendrite arm spacing, SDAS) and Si- and Fe-based eutectic structures on the mechanical properties and failure behavior of an Al-Si-Cu alloy are investigated. Cast Al alloy samples are produced using a special continuous-casting technique with which it is easy to control both the sizes of microstructures and the direction of crystal orientation. Dendrite cells appear to grow in the casting direction. There are linear correlations between SDAS and tensile properties (ultimate tensile strength σ UTS, 0.2 pct proof strength σ 0.2, and fracture strain ɛ f). These linear correlations, however, break down, especially for σ UTS vs SDAS and ɛ f vs SDAS, as the eutectic structures become more than 3 μm in diameter, when the strength and ductility ( σ UTS and ɛ f) decrease significantly. For eutectic structures larger than 3 μm, failure is dominated by the brittle eutectic phases, for which SDAS is no longer strongly correlated with σ UTS and ɛ f. In contrast, a linear correlation is obtained between σ 0.2 and SDAS, even for eutectic structures larger than 3 μm, and the eutectic structure does not have a strong effect on yield behavior. This is because failure in the eutectic phases occurs just before final fracture. In situ failure observation during tensile testing is performed using microstructural and lattice characteristics. From the experimental results obtained, models of failure during tensile loading are proposed.

  3. Systematic biobanking, novel imaging techniques, and advanced molecular analysis for precise tumor diagnosis and therapy: The Polish MOBIT project.

    PubMed

    Niklinski, Jacek; Kretowski, Adam; Moniuszko, Marcin; Reszec, Joanna; Michalska-Falkowska, Anna; Niemira, Magdalena; Ciborowski, Michal; Charkiewicz, Radoslaw; Jurgilewicz, Dorota; Kozlowski, Miroslaw; Ramlau, Rodryg; Piwkowski, Cezary; Kwasniewski, Miroslaw; Kaczmarek, Monika; Ciereszko, Andrzej; Wasniewski, Tomasz; Mroz, Robert; Naumnik, Wojciech; Sierko, Ewa; Paczkowska, Magdalena; Kisluk, Joanna; Sulewska, Anetta; Cybulski, Adam; Mariak, Zenon; Kedra, Boguslaw; Szamatowicz, Jacek; Kurzawa, Paweł; Minarowski, Lukasz; Charkiewicz, Angelika Edyta; Mroczko, Barbara; Malyszko, Jolanta; Manegold, Christian; Pilz, Lothar; Allgayer, Heike; Abba, Mohammed L; Juhl, Hartmut; Koch, Frauke

    2017-06-21

    Personalized and precision medicine is gaining recognition due to the limitations by standard diagnosis and treatment; many areas of medicine, from cancer to psychiatry, are moving towards tailored and individualized treatment for patients based on their clinical characteristics and genetic signatures as well as novel imaging techniques. Advances in whole genome sequencing have led to identification of genes involved in a variety of diseases. Moreover, biomarkers indicating severity of disease or susceptibility to treatment are increasingly being characterized. The continued identification of new genes and biomarkers specific to disease subtypes and individual patients is essential and inevitable for translation into personalized medicine, in estimating both, disease risk and response to therapy. Taking into consideration the mostly unsolved necessity of tailored therapy in oncology the innovative project MOBIT (molecular biomarkers for individualized therapy) was designed. The aims of the project are: (i) establishing integrative management of precise tumor diagnosis and therapy including systematic biobanking, novel imaging techniques, and advanced molecular analysis by collecting comprehensive tumor tissues, liquid biopsies (whole blood, serum, plasma), and urine specimens (supernatant; sediment) as well as (ii) developing personalized lung cancer diagnostics based on tumor heterogeneity and integrated genomics, transcriptomics, metabolomics, and radiomics PET/MRI analysis. It will consist of 5 work packages. In this paper the rationale of the Polish MOBIT project as well as its design is presented. (iii) The project is to draw interest in and to invite national and international, private and public, preclinical and clinical initiatives to establish individualized and precise procedures for integrating novel targeted therapies and advanced imaging techniques. Copyright © 2017 Medical University of Bialystok. Published by Elsevier B.V. All rights reserved.

  4. High-Precision Isotope Analysis of Uranium and Thorium by TIMS

    NASA Astrophysics Data System (ADS)

    Neymark, L. A.; Paces, J. B.

    2006-12-01

    The U.S. Geological Survey (USGS) Yucca Mountain Project Branch laboratory in Denver, Colorado, conducts routine high-precision isotope analyses of uranium (U) and thorium (Th) using thermal ionization mass- spectrometry (TIMS). The measurements are conducted by a ThermoFinnigan Triton\\texttrademark equipped with a Faraday multi-collector system and an energy filter in front of an active-film-type secondary electron multiplier (SEM). The abundance sensitivity of the instrument (signal at mass 237 over 238U in natural U) with the energy filter is about 15 ppb and peak tails are reduced by a factor of about 100 relative to the Faraday cup measurements. Since instrument installation in April 2004, more than 500 rock and water samples have been analyzed in support of isotope-geochemical studies for the U.S. Department of Energy`s Yucca Mountain Project. Isotope ratios of sub-nanogram to microgram U and Th samples are measured on graphite-coated single- filament and double-filament assemblies using zone-refined rhenium filaments. Ion beams less than 5 mV are measured with the SEM, which is corrected for non-linearity on the basis of measurements of NIST U-500 and 4321B standards with ion beams ranging from 0.01 to 8 mV. Inter-calibration between the SEM and the Faraday multi-collector is performed for every mass cycle using a 5 mV beam switched between Faraday cup and SEM (bridging technique), because SEM-Faraday inter-calibrations prior to the measurement failed to produce acceptable results. Either natural (^{235}U) or artificial (^{236}U, ^{229}Th) isotopes were used for the bridging. Separate runs are conducted for minor isotopes using SEM only. These techniques result in high within-run precisions of less than 0.1 to 0.2 percent for 234U/238U and 0.2 to 0.5 percent for 230Th/238U. The performance of the instrument is monitored using several U and Th isotope standards. The mean measured 234U/238U in NIST SRM 4321B is (52.879±0.004)×10-6 (95 percent confidence, n

  5. Towards an understanding of dark matter: Precise gravitational lensing analysis complemented by robust photometric redshifts

    NASA Astrophysics Data System (ADS)

    Coe, Daniel Aaron

    The goal of thesis is to help scientists resolve one of the great mysteries of our time: the nature of Dark Matter. Dark Matter is currently believed to make up over 80% of the material in our universe, yet we have so far inferred but a few of its basic properties. Here we study the Dark Matter surrounding a galaxy cluster, Abell 1689, via the most direct method currently available--gravitational lensing. Abell 1689 is a "strong" gravitational lens, meaning it produces multiple images of more distant galaxies. The observed positions of these images can be measured very precisely and act as a blueprint allowing us to reconstruct the Dark Matter distribution of the lens. Until now, such mass models of Abell 1689 have reproduced the observed multiple images well but with significant positional offsets. Using a new method we develop here, we obtain a new mass model which perfectly reproduces the observed positions of 168 knots identified within 135 multiple images of 42 galaxies. An important ingredient to our mass model is the accurate measurement of distances to the lensed galaxies via their photometric redshifts. Here we develop tools which improve the accuracy of these measurements based on our study of the Hubble Ultra Deep Field, the only image yet taken to comparable depth as the magnified regions of Abell 1689. We present results both for objects in the Hubble Ultra Deep Field and for galaxies gravitationally lensed by Abell 1689. As part of this thesis, we also provide reviews of Dark Matter and Gravitational Lensing, including a chapter devoted to the mass profiles of Dark Matter halos realized in simulations. The original work presented here was performed primarily by myself under the guidance of Narciso Benítez and Holland Ford as a member of the Advanced Camera for Surveys GTO Science Team at Johns Hopkins University and the Instituto de Astrofisica de Andalucfa. My advisors served on my thesis committee along with Rick White, Gabor Domokos, and Steve

  6. A combined parametric quadratic programming and precise integration method based dynamic analysis of elastic-plastic hardening/softening problems

    NASA Astrophysics Data System (ADS)

    Hongwu, Zhang; Xinwei, Zhang

    2002-12-01

    The objective of the paper is to develop a new algorithm for numerical solution of dynamic elastic-plastic strain hardening/softening problems. The gradient dependent model is adopted in the numerical model to overcome the result mesh-sensitivity problem in the dynamic strain softening or strain localization analysis. The equations for the dynamic elastic-plastic problems are derived in terms of the parametric variational principle, which is valid for associated, non-associated and strain softening plastic constitutive models in the finite element analysis. The precise integration method, which has been widely used for discretization in time domain of the linear problems, is introduced for the solution of dynamic nonlinear equations. The new algorithm proposed is based on the combination of the parametric quadratic programming method and the precise integration method and has all the advantages in both of the algorithms. Results of numerical examples demonstrate not only the validity, but also the advantages of the algorithm proposed for the numerical solution of nonlinear dynamic problems.

  7. High-precision technique for in-situ testing of the PZT scanner based on fringe analysis

    NASA Astrophysics Data System (ADS)

    Wang, Daodang; Yang, Yongying; Liu, Dong; Zhuo, Yongmo

    2010-08-01

    A technique based on fringe analysis is presented for the in-situ testing of the PZT scanner, including the end rotation analysis and displacement measurement. With the interferograms acquired in the Twyman-Green interferometer, the testing can be carried out in real time. The end rotation of the PZT scanner and its spatial displacement deviation are analyzed by processing the fringe rotation and interval changes; displacement of the PZT scanner is determined by fringe shift according to the algorithm of template-matching, from which the relation between the driving voltage and displacement is measured to calibrate the nonlinearity of the PZT scanner. It is shown by computer simulation and experiments that the proposed technique for in-situ testing of the PZT scanner takes a short time, and achieves precise displacement measurement as well as the end rotation angle and displacement deviation measurement. The proposed method has high efficiency and precision, and is of great practicality for in-situ calibration of the PZT scanner.

  8. Finite element analysis of helicopter structures

    NASA Technical Reports Server (NTRS)

    Rich, M. J.

    1978-01-01

    Application of the finite element analysis is now being expanded to three dimensional analysis of mechanical components. Examples are presented for airframe, mechanical components, and composite structure calculations. Data are detailed on the increase of model size, computer usage, and the effect on reducing stress analysis costs. Future applications for use of finite element analysis for helicopter structures are projected.

  9. Probabilistic structural analysis methods development for SSME

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Hopkins, D. A.

    1988-01-01

    The development of probabilistic structural analysis methods is a major part of the SSME Structural Durability Program and consists of three program elements: composite load spectra, probabilistic finite element structural analysis, and probabilistic structural analysis applications. Recent progress includes: (1) the effects of the uncertainties of several factors on the HPFP blade temperature pressure and torque, (2) the evaluation of the cumulative distribution function of structural response variables based on assumed uncertainties on primitive structural variables, and (3) evaluation of the failure probability. Collectively, the results obtained demonstrate that the structural durability of critical SSME components can be probabilistically evaluated.

  10. Image analysis techniques: Used to quantify and improve the precision of coatings testing results

    SciTech Connect

    Duncan, D.J.; Whetten, A.R.

    1993-12-31

    Coating evaluations often specify tests to measure performance characteristics rather than coating physical properties. These evaluation results are often very subjective. A new tool, Digital Video Image Analysis (DVIA), is successfully being used for two automotive evaluations; cyclic (scab) corrosion, and gravelometer (chip) test. An experimental design was done to evaluate variability and interactions among the instrumental factors. This analysis method has proved to be an order of magnitude more sensitive and reproducible than the current evaluations. Coating evaluations can be described and measured that had no way to be expressed previously. For example, DVIA chip evaluations can differentiate how much damage was done to the topcoat, primer even to the metal. DVIA with or without magnification, has the capability to become the quantitative measuring tool for several other coating evaluations, such as T-bends, wedge bends, acid etch analysis, coating defects, observing cure, defect formation or elimination over time, etc.

  11. Analysis of 14C and 13C in teeth provides precise birth dating and clues to geographical origin

    PubMed Central

    K, Alkass; BA, Buchholz; H, Druid; KL, Spalding

    2011-01-01

    The identification of human bodies in situations when there are no clues as to the person’s identity from circumstantial data, poses a difficult problem to investigators. The determination of age and sex of the body can be crucial in order to limit the search to individuals that are a possible match. We analyzed the proportion of bomb pulse derived carbon-14 (14C) incorporated in the enamel of teeth from individuals from different geographical locations. The ‘bomb pulse’ refers to a significant increase in 14C levels in the atmosphere caused by above ground test detonations of nuclear weapons during the cold war (1955-1963). By comparing 14C levels in enamel with 14C atmospheric levels systematically recorded over time, high precision birth dating of modern biological material is possible. Above ground nuclear bomb testing was largely restricted to a couple of locations in the northern hemisphere, producing differences in atmospheric 14C levels at various geographical regions, particularly in the early phase. Therefore, we examined the precision of 14C birth dating of enamel as a function of time of formation and geographical location. We also investigated the use of the stable isotope 13C as an indicator of geographical origin of an individual. Dental enamel was isolated from 95 teeth extracted from 84 individuals to study the precision of the 14C method along the bomb spike. For teeth formed before 1955 (N = 17), all but one tooth showed negative Δ14C values. Analysis of enamel from teeth formed during the rising part of the bomb-spike (1955-1963, N = 12) and after the peak (>1963, N = 66) resulted in an average absolute date of birth estimation error of 1.9 ±1.4 and 1.3 ± 1.0 years, respectively. Geographical location of an individual had no adverse effect on the precision of year of birth estimation using radiocarbon dating. In 46 teeth, measurement of 13C was also performed. Scandinavian teeth showed a substantially greater depression in average δ13C

  12. Analysis of 14C and 13C in teeth provides precise birth dating and clues to geographical origin.

    PubMed

    Alkass, K; Buchholz, B A; Druid, H; Spalding, K L

    2011-06-15

    The identification of human bodies in situations when there are no clues as to the person's identity from circumstantial data, poses a difficult problem to the investigators. The determination of age and sex of the body can be crucial in order to limit the search to individuals that are a possible match. We analyzed the proportion of bomb pulse derived carbon-14 ((14)C) incorporated in the enamel of teeth from individuals from different geographical locations. The 'bomb pulse' refers to a significant increase in (14)C levels in the atmosphere caused by above ground test detonations of nuclear weapons during the cold war (1955-1963). By comparing (14)C levels in enamel with (14)C atmospheric levels systematically recorded over time, high precision birth dating of modern biological material is possible. Above ground nuclear bomb testing was largely restricted to a couple of locations in the northern hemisphere, producing differences in atmospheric (14)C levels at various geographical regions, particularly in the early phase. Therefore, we examined the precision of (14)C birth dating of enamel as a function of time of formation and geographical location. We also investigated the use of the stable isotope (13)C as an indicator of geographical origin of an individual. Dental enamel was isolated from 95 teeth extracted from 84 individuals to study the precision of the (14)C method along the bomb spike. For teeth formed before 1955 (N=17), all but one tooth showed negative Δ(14)C values. Analysis of enamel from teeth formed during the rising part of the bomb-spike (1955-1963, N=12) and after the peak (>1963, N=66) resulted in an average absolute date of birth estimation error of 1.9±1.4 and 1.3±1.0 years, respectively. Geographical location of an individual had no adverse effect on the precision of year of birth estimation using radiocarbon dating. In 46 teeth, measurement of (13)C was also performed. Scandinavian teeth showed a substantially greater depression in

  13. A multiple ion counter total evaporation (MICTE) method for precise analysis of plutonium by thermal ionization mass spectrometry

    DOE PAGES

    Inglis, Jeremy D.; Maassen, Joel; Kara, Azim; ...

    2017-04-28

    This study presents a total evaporation method for the analysis of sub-picogram quantities of Pu, utilizing an array of multiple ion counters. Data from three standards are presented to assess the utility of the technique. An external precision of 1.5% RSD (2σ) was achieved on aliquots approaching 100 fg for the minor 240Pu isotope. Accurate analysis of <1 femtogram of 240Pu, is achievable, with an external reproducibility of better than 10% RSD (2σ). Finally, this new technique represents a significant advance in the total evaporation method and will allow routine measurement of femtogram sized Pu samples by thermal ionization massmore » spectrometry.« less

  14. Evaluation of the accuracy, precision and validity of hydrophilic vinyl polysiloxane impression material for bite mark analysis.

    PubMed

    Reddy, Sujatha S; Rakesh, N; Kaushik, Atul; Devaraju, D; Kumar, B S Nanda

    2011-01-01

    The present study was undertaken to assess the accuracy, precision and validity of hydrophilic Vinyl Poly Siloxane [VPS] impression material for bite mark documentation and analysis. Medium body VPS impressions of maxillary and mandibular anterior teeth among thirty subjects were taken and dental stone casts prepared. Hollow volume overlays were made and metric analysis was done using advanced imaging software like Adobe Photoshop - 9 and Image J. These values were compared to the measurements taken from bite mark impressions of the same 30 individuals on wax wafers using light body VPS material. The mean differences in the parameters measured by the different techniques were compared using Intra Class Correlation Coefficients [ICCC]. Additionally validity parameters such as sensitivity, specificity, positive and negative predictive value were computed.

  15. Evaluation of the accuracy, precision and validity of hydrophilic vinyl polysiloxane impression material for bite mark analysis

    PubMed Central

    Reddy, Sujatha S.; Rakesh, N.; Kaushik, Atul; Devaraju, D.; Kumar, B.S. Nanda

    2011-01-01

    The present study was undertaken to assess the accuracy, precision and validity of hydrophilic Vinyl Poly Siloxane [VPS] impression material for bite mark documentation and analysis. Medium body VPS impressions of maxillary and mandibular anterior teeth among thirty subjects were taken and dental stone casts prepared. Hollow volume overlays were made and metric analysis was done using advanced imaging software like Adobe Photoshop - 9 and Image J. These values were compared to the measurements taken from bite mark impressions of the same 30 individuals on wax wafers using light body VPS material. The mean differences in the parameters measured by the different techniques were compared using Intra Class Correlation Coefficients [ICCC]. Additionally validity parameters such as sensitivity, specificity, positive and negative predictive value were computed. PMID:27857665

  16. A high precision gas flow cell for performing in situ neutron studies of local atomic structure in catalytic materials.

    PubMed

    Olds, Daniel; Page, Katharine; Paecklar, Arnold; Peterson, Peter F; Liu, Jue; Rucker, Gerald; Ruiz-Rodriguez, Mariano; Olsen, Michael; Pawel, Michelle; Overbury, Steven H; Neilson, James R

    2017-03-01

    Gas-solid interfaces enable a multitude of industrial processes, including heterogeneous catalysis; however, there are few methods available for studying the structure of this interface under operating conditions. Here, we present a new sample environment for interrogating materials under gas-flow conditions using time-of-flight neutron scattering under both constant and pulse probe gas flow. Outlined are descriptions of the gas flow cell and a commissioning example using the adsorption of N2 by Ca-exchanged zeolite-X (Na78-2xCaxAl78Si144O384,x ≈ 38). We demonstrate sensitivities to lattice contraction and N2 adsorption sites in the structure, with both static gas loading and gas flow. A steady-state isotope transient kinetic analysis of N2 adsorption measured simultaneously with mass spectrometry is also demonstrated. In the experiment, the gas flow through a plugged-flow gas-solid contactor is switched between N215 and N214 isotopes at a temperature of 300 K and a constant pressure of 1 atm; the gas flow and mass spectrum are correlated with the structure factor determined from event-based neutron total scattering. Available flow conditions, sample considerations, and future applications are discussed.

  17. A high precision gas flow cell for performing in situ neutron studies of local atomic structure in catalytic materials

    DOE PAGES

    Olds, Daniel; Page, Katharine; Paecklar, Arnold A.; ...

    2017-03-17

    Gas-solid interfaces enable a multitude of industrial processes, including heterogeneous catalysis; however, there are few methods available for studying the structure of this interface under operating conditions. Here, we present a new sample environment for interrogating materials under gas-flow conditions using time-of-flight neutron scattering under both constant and pulse probe gas flow. Outlined are descriptions of the gas flow cell and a commissioning example using the adsorption of N2 by Ca-exchanged zeolite-X (Na78–2xCaxAl78Si144O384,x ≈ 38). We demonstrate sensitivities to lattice contraction and N2 adsorption sites in the structure, with both static gas loading and gas flow. A steady-state isotope transientmore » kinetic analysis of N2 adsorption measured simultaneously with mass spectrometry is also demonstrated. In the experiment, the gas flow through a plugged-flow gas-solid contactor is switched between 15N2 and 14N2 isotopes at a temperature of 300 K and a constant pressure of 1 atm; the gas flow and mass spectrum are correlated with the structure factor determined from event-based neutron total scattering. As a result, available flow conditions, sample considerations, and future applications are discussed.« less

  18. A high precision gas flow cell for performing in situ neutron studies of local atomic structure in catalytic materials

    NASA Astrophysics Data System (ADS)

    Olds, Daniel; Page, Katharine; Paecklar, Arnold; Peterson, Peter F.; Liu, Jue; Rucker, Gerald; Ruiz-Rodriguez, Mariano; Olsen, Michael; Pawel, Michelle; Overbury, Steven H.; Neilson, James R.

    2017-03-01

    Gas-solid interfaces enable a multitude of industrial processes, including heterogeneous catalysis; however, there are few methods available for studying the structure of this interface under operating conditions. Here, we present a new sample environment for interrogating materials under gas-flow conditions using time-of-flight neutron scattering under both constant and pulse probe gas flow. Outlined are descriptions of the gas flow cell and a commissioning example using the adsorption of N2 by Ca-exchanged zeolite-X (Na78-2xCaxAl78Si144O384,x ≈ 38). We demonstrate sensitivities to lattice contraction and N2 adsorption sites in the structure, with both static gas loading and gas flow. A steady-state isotope transient kinetic analysis of N2 adsorption measured simultaneously with mass spectrometry is also demonstrated. In the experiment, the gas flow through a plugged-flow gas-solid contactor is switched between 15N2 and 14N2 isotopes at a temperature of 300 K and a constant pressure of 1 atm; the gas flow and mass spectrum are correlated with the structure factor determined from event-based neutron total scattering. Available flow conditions, sample considerations, and future applications are discussed.

  19. Three-dimensional velocity structure and high-precision earthquake relocations at Augustine, Akutan, and Makushin Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Syracuse, E. M.; Thurber, C. H.; Power, J. A.; Prejean, S. G.

    2010-12-01

    Alaska contains over 100 volcanoes, 21 of which have been active within the past 20 years, including Augustine in Cook Inlet, and Akutan and Makushin in the central Aleutian arc. We incorporate 14-15 years of earthquake data from the Alaska Volcano Observatory (AVO) to obtain P-wave velocity structure and high-precision earthquake locations at each volcano. At Augustine, most relocated seismicity is beneath the summit at an average depth of 0.6 km. In the weeks leading to the 2006 eruption, seismicity shallowed and focused on a NW-SE line, suggestive of an inflating dike. Through August 2006, intermittent seismicity was observed at 1 to 4.5 km depth, pointing to an association with the transport of magma. Active-source data are also incorporated into the tomographic inversion, illuminating a high-velocity column beneath the summit, and elevated velocities on the south flank. The high-velocity column surrounds the observed deeper seismicity and is likely due to intruded volcanic material. The elevated velocities on the south flank are associated with uplifted zeolitzed sandstones. Akutan most recently erupted in 1992, before the seismic network was installed. Most seismicity is above 9 km depth, with 10% occurring between 14 to30 km depth. Seismicity is separated into two main groups that dip away from the caldera—one to the east and one to the west. The eastern group contains earthquakes from a swarm in early 1996 and the western group contains earthquakes from mid-1996 through the present that form rough lines radiating from the summit. Ongoing seismicity also occurs in a broader region beneath the caldera. Makushin most recently erupted in 1995, also prior to seismic monitoring by AVO. Relocations here show that most seismicity is at 3 to 13 km depth and either beneath the caldera or within one of two dipping clusters 20 km to the northeast. Additional seismicity occurs at up to 25 km depth beneath the summit, as well as scattered throughout the island at

  20. Precision translator

    DOEpatents

    Reedy, Robert P.; Crawford, Daniel W.

    1984-01-01

    A precision translator for focusing a beam of light on the end of a glass fiber which includes two turning fork-like members rigidly connected to each other. These members have two prongs each with its separation adjusted by a screw, thereby adjusting the orthogonal positioning of a glass fiber attached to one of the members. This translator is made of simple parts with capability to keep adjustment even in condition of rough handling.

  1. Precision translator

    DOEpatents

    Reedy, R.P.; Crawford, D.W.

    1982-03-09

    A precision translator for focusing a beam of light on the end of a glass fiber which includes two turning fork-like members rigidly connected to each other. These members have two prongs each with its separation adjusted by a screw, thereby adjusting the orthogonal positioning of a glass fiber attached to one of the members. This translator is made of simple parts with capability to keep adjustment even in condition of rough handling.

  2. Accuracy and Precision Analysis of Chamber-Based Nitrous Oxide Gas Flux Estimates

    USDA-ARS?s Scientific Manuscript database

    Previous analysis of chamber-based nitrous oxide (N2O) gas flux estimate errors has not considered the impacts of soil biological uptake and has not closely examined the influence of measurement error on resulting flux estimates. Simulation modeling is used here to demonstrate that chamber N2O conce...

  3. The Penny Experiment Revisited: An Illustration of Significant Figures, Accuracy, Precision, and Data Analysis

    ERIC Educational Resources Information Center

    Bularzik, Joseph

    2007-01-01

    Measuring the mass of many pennies has been used as an easy way to generate data for exercises with statistical analysis. In this general chemistry laboratory the densities of pennies are measured by weighting the pennies and using two different methods to measure the volumes. There is much to be discovered by the students on the variability of…

  4. Accuracy and Precision for EchoMRI-Infants™ Body Composition Analysis in Piglets

    USDA-ARS?s Scientific Manuscript database

    Body Composition Analysis is used to evaluate infant growth patterns, efficacy of nutritional and medical interventions, progression of chronic disease, and recovery from malnutrition. EchoMRI-Infants is a new Quantitative Magnetic Resonance (QMR) method to measure Total Body Fat, Lean Tissue Mass, ...

  5. Accuracy and precision of minimally-invasive cardiac output monitoring in children: a systematic review and meta-analysis.

    PubMed

    Suehiro, Koichi; Joosten, Alexandre; Murphy, Linda Suk-Ling; Desebbe, Olivier; Alexander, Brenton; Kim, Sang-Hyun; Cannesson, Maxime

    2016-10-01

    Several minimally-invasive technologies are available for cardiac output (CO) measurement in children, but the accuracy and precision of these devices have not yet been evaluated in a systematic review and meta-analysis. We conducted a comprehensive search of the medical literature in PubMed, Cochrane Library of Clinical Trials, Scopus, and Web of Science from its inception to June 2014 assessing the accuracy and precision of all minimally-invasive CO monitoring systems used in children when compared with CO monitoring reference methods. Pooled mean bias, standard deviation, and mean percentage error of included studies were calculated using a random-effects model. The inter-study heterogeneity was also assessed using an I(2) statistic. A total of 20 studies (624 patients) were included. The overall random-effects pooled bias, and mean percentage error were 0.13 ± 0.44 l min(-1) and 29.1 %, respectively. Significant inter-study heterogeneity was detected (P < 0.0001, I(2) = 98.3 %). In the sub-analysis regarding the device, electrical cardiometry showed the smallest bias (-0.03 l min(-1)) and lowest percentage error (23.6 %). Significant residual heterogeneity remained after conducting sensitivity and subgroup analyses based on the various study characteristics. By meta-regression analysis, we found no independent effects of study characteristics on weighted mean difference between reference and tested methods. Although the pooled bias was small, the mean pooled percentage error was in the gray zone of clinical applicability. In the sub-group analysis, electrical cardiometry was the device that provided the most accurate measurement. However, a high heterogeneity between studies was found, likely due to a wide range of study characteristics.

  6. A comparative study of submicron particle sizing platforms: accuracy, precision and resolution analysis of polydisperse particle size distributions.

    PubMed

    Anderson, Will; Kozak, Darby; Coleman, Victoria A; Jämting, Åsa K; Trau, Matt

    2013-09-01

    The particle size distribution (PSD) of a polydisperse or multimodal system can often be difficult to obtain due to the inherent limitations in established measurement techniques. For this reason, the resolution, accuracy and precision of three new and one established, commercially available and fundamentally different particle size analysis platforms were compared by measuring both individual and a mixed sample of monodisperse, sub-micron (220, 330, and 410 nm - nominal modal size) polystyrene particles. The platforms compared were the qNano Tunable Resistive Pulse Sensor, Nanosight LM10 Particle Tracking Analysis System, the CPS Instruments's UHR24000 Disc Centrifuge, and the routinely used Malvern Zetasizer Nano ZS Dynamic Light Scattering system. All measurements were subjected to a peak detection algorithm so that the detected particle populations could be compared to 'reference' Transmission Electron Microscope measurements of the individual particle samples. Only the Tunable Resistive Pulse Sensor and Disc Centrifuge platforms provided the resolution required to resolve all three particle populations present in the mixed 'multimodal' particle sample. In contrast, the light scattering based Particle Tracking Analysis and Dynamic Light Scattering platforms were only able to detect a single population of particles corresponding to either the largest (410 nm) or smallest (220 nm) particles in the multimodal sample, respectively. When the particle sets were measured separately (monomodal) each platform was able to resolve and accurately obtain a mean particle size within 10% of the Transmission Electron Microscope reference values. However, the broadness of the PSD measured in the monomodal samples deviated greatly, with coefficients of variation being ~2-6-fold larger than the TEM measurements across all four platforms. The large variation in the PSDs obtained from these four, fundamentally different platforms, indicates that great care must still be taken in

  7. Precision Cosmology

    NASA Astrophysics Data System (ADS)

    Jones, Bernard J. T.

    2017-04-01

    Preface; Notation and conventions; Part I. 100 Years of Cosmology: 1. Emerging cosmology; 2. The cosmic expansion; 3. The cosmic microwave background; 4. Recent cosmology; Part II. Newtonian Cosmology: 5. Newtonian cosmology; 6. Dark energy cosmological models; 7. The early universe; 8. The inhomogeneous universe; 9. The inflationary universe; Part III. Relativistic Cosmology: 10. Minkowski space; 11. The energy momentum tensor; 12. General relativity; 13. Space-time geometry and calculus; 14. The Einstein field equations; 15. Solutions of the Einstein equations; 16. The Robertson–Walker solution; 17. Congruences, curvature and Raychaudhuri; 18. Observing and measuring the universe; Part IV. The Physics of Matter and Radiation: 19. Physics of the CMB radiation; 20. Recombination of the primeval plasma; 21. CMB polarisation; 22. CMB anisotropy; Part V. Precision Tools for Precision Cosmology: 23. Likelihood; 24. Frequentist hypothesis testing; 25. Statistical inference: Bayesian; 26. CMB data processing; 27. Parametrising the universe; 28. Precision cosmology; 29. Epilogue; Appendix A. SI, CGS and Planck units; Appendix B. Magnitudes and distances; Appendix C. Representing vectors and tensors; Appendix D. The electromagnetic field; Appendix E. Statistical distributions; Appendix F. Functions on a sphere; Appendix G. Acknowledgements; References; Index.

  8. Very high precision and accuracy analysis of triple isotopic ratios of water. A critical instrumentation comparison study.

    NASA Astrophysics Data System (ADS)

    Gkinis, Vasileios; Holme, Christian; Morris, Valerie; Thayer, Abigail Grace; Vaughn, Bruce; Kjaer, Helle Astrid; Vallelonga, Paul; Simonsen, Marius; Jensen, Camilla Marie; Svensson, Anders; Maffrezzoli, Niccolo; Vinther, Bo; Dallmayr, Remi

    2017-04-01

    We present a performance comparison study between two state of the art Cavity Ring Down Spectrometers (Picarro L2310-i, L2140-i). The comparison took place during the Continuous Flow Analysis (CFA) campaign for the measurement of the Renland ice core, over a period of three months. Instant and complete vaporisation of the ice core melt stream, as well as of in-house water reference materials is achieved by accurate control of microflows of liquid into a homemade calibration system by following simple principles of the Hagen-Poiseuille law. Both instruments share the same vaporisation unit in a configuration that minimises sample preparation discrepancies between the two analyses. We describe our SMOW-SLAP calibration and measurement protocols for such a CFA application and present quality control metrics acquired during the full period of the campaign on a daily basis. The results indicate an unprecedented performance for all 3 isotopic ratios (δ2H, δ17O, δ18O ) in terms of precision, accuracy and resolution. We also comment on the precision and accuracy of the second order excess parameters of HD16O and H217O over H218O (Dxs, Δ17O ). To our knowledge these are the first reported CFA measurements at this level of precision and accuracy for all three isotopic ratios. Differences on the performance of the two instruments are carefully assessed during the measurement and reported here. Our quality control protocols extend to the area of low water mixing ratios, a regime in which often atmospheric vapour measurements take place and Cavity Ring Down Analysers show a poorer performance due to the lower signal to noise ratios. We address such issues and propose calibration protocols from which water vapour isotopic analyses can benefit from.

  9. High resolution and high precision on line isotopic analysis of Holocene and glacial ice performed in the field

    NASA Astrophysics Data System (ADS)

    Gkinis, V.; Popp, T. J.; Johnsen, S. J.; Blunier, T.; Bigler, M.; Stowasser, C.; Schüpbach, S.; Leuenberger, D.

    2010-12-01

    Ice core records as obtained from polar ice caps provide a wealth of paleoclimatic information. One of the main features of ice cores is their potential for high temporal resolution. The isotopic signature of the ice, expressed through the relative abundances of the two heavy isotopologues H218O and HD16O, is a widely used proxy for the reconstruction of past temperature and accumulation. One step further the combined information obtained from these two isotopologues, commonly referred to as the deuterium excess, can be utilized to infer additional information about the source of the precipitated moisture. Until very recently isotopic analysis of polar ice was performed with isotope Ratio Mass Spectrometry (IRMS) in a discrete fashion resulting in a high workload related to the preparation of samples. Most important though the available temporal resolution of the ice core was in many cases not fully exploited. In order to overcome these limitations we have developed a system that interfaces a commercially available IR laser cavity ring-down spectrometer tailored for water isotope analysis to a stream of liquid water as extracted from a continuously melted ice rod. The system offers the possibility for simultaneous δ18O and δD analysis with a sample requirement of approximately 0.1 ml/min. The system has been deployed in the field during the NEEM ice core drilling project on 2009 and 2010. In this study we present actual on line measurements of Holocene and glacial ice. We also discuss how parameters as the melt rate, acquisition rate and integration time affect the obtained precision and resolution and we describe data analysis techniques that can improve these last two parameters. By applying spectral methods we are able to quantify the smoothing effects imposed by diffusion of the sample in the sample transfer lines and the optical cavity of the instrument. We demonstrate that with an acquisition rate of 0.2 Hz we are able to obtain a precision of 0.5‰ and 0

  10. High precision analysis of isotopic composition for samples used for nuclear cross-section measurements

    NASA Astrophysics Data System (ADS)

    Shibahara, Yuji; Hori, Jun-ichi; Takamiya, Koichi; Fujii, Toshiyuki; Fukutani, Satoshi; Sano, Tadafumi; Harada, Hideo

    2017-09-01

    For the accuracy improvement of nuclear data of minor actinides and long-lived fission products in the project of "Research and development for Accuracy Improvement of neutron nuclear data on Minor Actinides", the isotopic compositions of two Am samples (241Am sample and 243Am sample) were analyzed by thermal ionization mass spectrometry. Only the peak of 241Am was observed in the analysis of 241Am sample, and level of isotopic impurities were improved from 0.1% to 0.0004%. In the analysis of 243Am sample, the peak of unreported isotope of 242mAm was observed in addition to the peaks of 243Am and 241Am. The mass spectrometry also showed that 243Am sample has other unreported impurities such as 239Pu and 240Pu.

  11. Text Mining for Precision Medicine: Bringing Structure to EHRs and Biomedical Literature to Understand Genes and Health.

    PubMed

    Simmons, Michael; Singhal, Ayush; Lu, Zhiyong

    2016-01-01

    The key question of precision medicine is whether it is possible to find clinically actionable granularity in diagnosing disease and classifying patient risk. The advent of next-generation sequencing and the widespread adoption of electronic health records (EHRs) have provided clinicians and researchers a wealth of data and made possible the precise characterization of individual patient genotypes and phenotypes. Unstructured text-found in biomedical publications and clinical notes-is an important component of genotype and phenotype knowledge. Publications in the biomedical literature provide essential information for interpreting genetic data. Likewise, clinical notes contain the richest source of phenotype information in EHRs. Text mining can render these texts computationally accessible and support information extraction and hypothesis generation. This chapter reviews the mechanics of text mining in precision medicine and discusses several specific use cases, including database curation for personalized cancer medicine, patient outcome prediction from EHR-derived cohorts, and pharmacogenomic research. Taken as a whole, these use cases demonstrate how text mining enables effective utilization of existing knowledge sources and thus promotes increased value for patients and healthcare systems. Text mining is an indispensable tool for translating genotype-phenotype data into effective clinical care that will undoubtedly play an important role in the eventual realization of precision medicine.

  12. Enhanced Precision of the New Hologic Horizon Model Compared With the Old Discovery Model Is Less Evident When Fewer Vertebrae Are Included in the Analysis.

    PubMed

    McNamara, Elizabeth A; Kilim, Holly P; Malabanan, Alan O; Whittaker, LaTarsha G; Rosen, Harold N

    2016-07-12

    The International Society for Clinical Densitometry guidelines recommend using locally derived precision data for spine bone mineral densities (BMDs), but do not specify whether data derived from L1-L4 spines correctly reflect the precision for spines reporting fewer than 4 vertebrae. Our experience suggested that the decrease in precision with successively fewer vertebrae is progressive as more vertebrae are excluded and that the precision for the newer Horizon Hologic model might be better than that for the previous model, and we sought to quantify. Precision studies were performed on Hologic densitometers by acquiring spine BMD in fast array mode twice on 30 patients, according to International Society for Clinical Densitometry guidelines. This was done 10 different times on various Discovery densitometers, and once on a Horizon densitometer. When 1 vertebral body was excluded from analysis, there was no significant deterioration in precision. When 2 vertebrae were excluded, there was a nonsignificant trend to poorer precision, and when 3 vertebrae were excluded, there was significantly worse precision. When 3 or 4 vertebrae were reported, the precision of the spine BMD measurement was significantly better on the Hologic Horizon than on the Discovery, but the difference in precision between densitometers narrowed and was no longer significant when 1 or 2 vertebrae were reported. The results suggest that (1) the measurement of in vivo spine BMD on the new Hologic Horizon densitometer is significantly more precise than on the older Discovery model; (2) the difference in precision between the Horizon and Discovery models decreases as fewer vertebrae are included; (3) the measurement of spine BMD is less precise as more vertebrae are excluded, but still quite reasonable even when only 1 vertebral body is included; and (4) when 3 vertebrae are reported, L1-L4 precision data can reasonably be used to report significance of changes in BMD. When 1 or 2 vertebrae are

  13. Gene expression analysis of precision-cut human liver slices indicates stable expression of ADME-Tox related genes

    SciTech Connect

    Elferink, M.G.L.; Olinga, P.; van Leeuwen, E.M.; Bauerschmidt, S.; Polman, J.; Schoonen, W.G.; Heisterkamp, S.H.; Groothuis, G.M.M.

    2011-05-15

    In the process of drug development it is of high importance to test the safety of new drugs with predictive value for human toxicity. A promising approach of toxicity testing is based on shifts in gene expression profiling of the liver. Toxicity screening based on animal liver cells cannot be directly extrapolated to humans due to species differences. The aim of this study was to evaluate precision-cut human liver slices as in vitro method for the prediction of human specific toxicity by toxicogenomics. The liver slices contain all cell types of the liver in their natural architecture. This is important since drug-induced toxicity often is a multi-cellular process. Previously we showed that toxicogenomic analysis of rat liver slices is highly predictive for rat in vivo toxicity. In this study we investigated the levels of gene expression during incubation up to 24 h with Affymetrix microarray technology. The analysis was focused on a broad spectrum of genes related to stress and toxicity, and on genes encoding for phase-I, -II and -III metabolizing enzymes and transporters. Observed changes in gene expression were associated with cytoskeleton remodeling, extracellular matrix and cell adhesion, but for the ADME-Tox related genes only minor changes were observed. PCA analysis showed that changes in gene expression were not associated with age, sex or source of the human livers. Slices treated with acetaminophen showed patterns of gene expression related to its toxicity. These results indicate that precision-cut human liver slices are relatively stable during 24 h of incubation and represent a valuable model for human in vitro hepatotoxicity testing despite the human inter-individual variability.

  14. High-content behavioral analysis of Caenorhabditis elegans in precise spatiotemporal chemical environments.

    PubMed

    Albrecht, Dirk R; Bargmann, Cornelia I

    2011-06-12

    To quantitatively understand chemosensory behaviors, it is desirable to present many animals with repeatable, well-defined chemical stimuli. To that end, we describe a microfluidic system to analyze Caenorhabditis elegans behavior in defined temporal and spatial stimulus patterns. A 2 cm × 2 cm structured arena allowed C. elegans to perform crawling locomotion in a controlled liquid environment. We characterized behavioral responses to attractive odors with three stimulus patterns: temporal pulses, spatial stripes and a linear concentration gradient, all delivered in the fluid phase to eliminate variability associated with air-fluid transitions. Different stimulus configurations preferentially revealed turning dynamics in a biased random walk, directed orientation into an odor stripe and speed regulation by odor. We identified both expected and unexpected responses in wild-type worms and sensory mutants by quantifying dozens of behavioral parameters. The devices are inexpensive, easy to fabricate, reusable and suitable for delivering any liquid-borne stimulus.

  15. Error Analysis of the S-Step Lanczos Method in Finite Precision

    DTIC Science & Technology

    2014-05-06

    v0, . . . , vm] and the (m+1)-by-(m+1) symmetric tridiagonal matrix Tm such that AVm = VmTm + βm+1vm+1e T m+1. (1.1) When m = n − 1, the...eigenproblem, IMA J. Appl. Math., 10 (1972), pp. 373–381. [27] , Error analysis of the Lanczos algorithm for tridiagonalizing a symmetric matrix , IMA J...n symmetric matrix A and a starting vector v0 with unit 2-norm, m steps of the Lanczos method [21] theoretically produces the or- thonormal matrix Vm

  16. Isotopic analysis of small Pb samples using MC-ICPMS: The limits of precision and comparison to TIMS

    NASA Astrophysics Data System (ADS)

    Amelin, Y.; Janney, P.; Chakrabarti, R.; Wadhwa, M.; Jacobsen, S. B.

    2008-12-01

    Multicollector ICP-MS is a mainstream method for precise isotopic analyses of large (over 10-8 g) quantities of Pb, and is becoming increasingly popular for very rapid, even if relatively imprecise, U-Pb dating of U-bearing minerals using laser ablation. At the same time, high precision U-Pb geo- and cosmo- chronology mainly utilizes isotope dilution thermal ionization mass spectrometry, recently enhanced by application of double spikes for both Pb and U. Here we explore the suitability of MC-ICPMS for analysis of 10-11-10-9 g quantities of radiogenic Pb, contained in small single grains of zircon and other U- bearing minerals, and in chondrules, refractory inclusions and mineral fractions from meteorites. Analyses were performed at the Geological Survey of Canada using a Nu Plasma with DSN-100 desolvating nebulizer, at Arizona State University using a Neptune with Apex nebulizer, and at Harvard University using an Isoprobe P with Apex nebulizer. A total ion yield of 0.4-0.5% was achieved in all three instruments in 2.5-4 minute analyses. The fractions of SRM-981 and SRM-983 standards, spiked with 202Pb-205Pb- 233U-235U [1], containing between 3*10-11 and 10-9 Pb, were analyzed in all three labs. Precision of 207Pb/206Pb ratios in SRM-981 was 0.1-0.3% for 3*10-11 g fractions, 0.03-0.1% for 10-10 g fractions, and 0.006-0.013% for 10-9 g fractions. Precision of the best MC-ICPMS analyses was similar to precision of average TIMS analyses from the same quantities of Pb. Reproducibility of analyses depends on accurate blank and background subtraction as much as on the counting statistics. A series of analyses of the same solution run within a short period of time (i.e. with constant background) yielded a reproducibility similar to that of TIMS, whereas the analyses of a series of separately prepared aliquots were less reproducible. Our data demonstrate that the quality of analyses of 10^11 - 10^9 g Pb fractions by modern MC-ICPMS approaches the quality of TIMS analyses

  17. Design and analysis of a large-diameter precision optical mount for NFIRAOS

    NASA Astrophysics Data System (ADS)

    Fitzsimmons, Joeleff; Hill, Alexis

    2014-08-01

    This study describes the design evolution, finite element analysis (FEA) and experimental testing completed to develop the large optical mounts for the Near-Field IR Adaptive Optics System (NFIRAOS), the facility Adaptive Optics system for the Thirty Meter Telescope (TMT). The mount design incorporates a unique combination of bonded flexure-based linear actuators and a roller-chain radial support. Extensive FEA was completed to refine the design to ensure the final mount design will meet the required operational performance. Experimental work was conducted to ensure that the suitability of the bonded interface between the optic and the flexures and to verify that the high bond stiffness did not cause fracture of the glass during thermal cycling.

  18. Precise and fast spatial-frequency analysis using the iterative local Fourier transform.

    PubMed

    Lee, Sukmock; Choi, Heejoo; Kim, Dae Wook

    2016-09-19

    The use of the discrete Fourier transform has decreased since the introduction of the fast Fourier transform (fFT), which is a numerically efficient computing process. This paper presents the iterative local Fourier transform (ilFT), a set of new processing algorithms that iteratively apply the discrete Fourier transform within a local and optimal frequency domain. The new technique achieves 210 times higher frequency resolution than the fFT within a comparable computation time. The method's superb computing efficiency, high resolution, spectrum zoom-in capability, and overall performance are evaluated and compared to other advanced high-resolution Fourier transform techniques, such as the fFT combined with several fitting methods. The effectiveness of the ilFT is demonstrated through the data analysis of a set of Talbot self-images (1280 × 1024 pixels) obtained with an experimental setup using grating in a diverging beam produced by a coherent point source.

  19. Cost analysis of pulmonary lobectomy procedure: comparison of stapler versus precision dissection and sealant

    PubMed Central

    Droghetti, Andrea; Marulli, Giuseppe; Vannucci, Jacopo; Giovanardi, Michele; Bottoli, Maria Caterina; Ragusa, Mark; Muriana, Giovanni

    2017-01-01

    Objective We aimed to evaluate the direct costs of pulmonary lobectomy hospitalization, comparing surgical techniques for the division of interlobar fissures: stapler (ST) versus electrocautery and hemostatic sealant patch (ES). Methods The cost comparison analysis was based on the clinical pathway and drawn up by collecting the information available from the Thoracic Surgery Division medical team at Mantova Hospital. Direct resource consumption was derived from a previous randomized controlled trial including 40 patients. Use and maintenance of technology, equipment and operating room; administrative plus general costs; and 30-day use of postsurgery hospital resources were considered. The analysis was conducted from the hospital perspective. Results On the average, a patient submitted to pulmonary lobectomy costs €9,744.29. This sum could vary from €9,027 (using ES) to €10,460 (using ST). The overall lower incidence (50% vs 95%, P=0.0001) and duration of air leakage (1.7 days vs 4.5 days, P=0.0001) in the ES group significantly affects the mean time of hospital stay (11.0 days vs 14.3 days) and costs. Cost saving in the ES group was also driven by the lower incidence of complications. The main key cost driver was staff employment (42%), then consumables (34%) and operating room costs (12%). Conclusion There is an overall saving of around €1,432.90 when using ES patch for each pulmonary lobectomy. Among patients undergoing this surgical procedure, ES can significantly reduce air leakage incidence and duration, as well as decrease hospitalization rates. However, further multicenter research should be developed considering different clinical and managerial settings. PMID:28408847

  20. The integral suspension pressure method (ISP) for precise particle-size analysis by gravitational sedimentation

    NASA Astrophysics Data System (ADS)

    Durner, Wolfgang; Iden, Sascha C.; von Unold, Georg

    2017-04-01

    The particle-size distribution (PSD) of a soil expresses the mass fractions of various sizes of mineral particles which constitute the soil material. It is a fundamental soil property, closely related to most physical and chemical soil properties and it affects almost any soil function. The experimental determination of soil texture, i.e., the relative amounts of sand, silt, and clay-sized particles, is done in the laboratory by a combination of sieving (sand) and gravitational sedimentation (silt and clay). In the latter, Stokes' law is applied to derive the particle size from the settling velocity in an aqueous suspension. Traditionally, there are two methodologies for particle-size analysis from sedimentation experiments: the pipette method and the hydrometer method. Both techniques rely on measuring the temporal change of the particle concentration or density of the suspension at a certain depth within the suspension. In this paper, we propose a new method which is based on the pressure in the suspension at a selected depth, which is an integral measure of all particles in suspension above the measuring depth. We derive a mathematical model which predicts the pressure decrease due to settling of particles as function of the PSD. The PSD of the analyzed sample is identified by fitting the simulated time series of pressure to the observed one by inverse modeling using global optimization. The new method yields the PSD in very high resolution and its experimental realization completely avoids any disturbance by the measuring process. A sensitivity analysis of different soil textures demonstrates that the method yields unbiased estimates of the PSD with very small estimation variance and an absolute error in the clay and silt fraction of less than 0.5%

  1. The integral suspension pressure method (ISP) for precise particle-size analysis by gravitational sedimentation

    NASA Astrophysics Data System (ADS)

    Durner, Wolfgang; Iden, Sascha C.; von Unold, Georg

    2017-01-01

    The particle-size distribution (PSD) of a soil expresses the mass fractions of various sizes of mineral particles which constitute the soil material. It is a fundamental soil property, closely related to most physical and chemical soil properties and it affects almost any soil function. The experimental determination of soil texture, i.e., the relative amounts of sand, silt, and clay-sized particles, is done in the laboratory by a combination of sieving (sand) and gravitational sedimentation (silt and clay). In the latter, Stokes' law is applied to derive the particle size from the settling velocity in an aqueous suspension. Traditionally, there are two methodologies for particle-size analysis from sedimentation experiments: the pipette method and the hydrometer method. Both techniques rely on measuring the temporal change of the particle concentration or density of the suspension at a certain depth within the suspension. In this paper, we propose a new method which is based on the pressure in the suspension at a selected depth, which is an integral measure of all particles in suspension above the measuring depth. We derive a mathematical model which predicts the pressure decrease due to settling of particles as function of the PSD. The PSD of the analyzed sample is identified by fitting the simulated time series of pressure to the observed one by inverse modeling using global optimization. The new method yields the PSD in very high resolution and its experimental realization completely avoids any disturbance by the measuring process. A sensitivity analysis of different soil textures demonstrates that the method yields unbiased estimates of the PSD with very small estimation variance and an absolute error in the clay and silt fraction of less than 0.5%.

  2. Magnetic Microcalorimeter Gamma Detectors for High-Precision Non-Destructive Analysis

    SciTech Connect

    Friedrich, Stephan; Bates, Cameron; Pereverzev, Sergey

    2014-10-03

    Cryogenic gamma (γ) detectors with operating temperatures of ~0.1 K offer 10× better energy resolution than conventional high-purity germanium detectors that are currently used for non-destructive analysis (NDA) of nuclear materials. This can greatly increase the accuracy of NDA, especially at low-energies where gamma rays often have similar energies and cannot be resolved by Ge detectors. Among the different cryogenic detector types, Magnetic Micro-Calorimeters (MMCs) have the potential of faster count rates and better linearity. High linearity is essential to add spectra from different pixels in detector arrays that are needed for high sensitivity. MMC gamma detectors measure the energy of absorbed gamma rays form the resulting change in magnetization of an erbium-doped gold (Au:Er) sensor. The signal is read out with a SQUID preamplifier and processed digitally with room temperature electronics (see inset figure 2). The objective of this project is to develop ultra-high energy resolution γ-detectors based on magnetic micro-calorimeters (MMCs) for accurate non-destructive isotope analysis (NDA). Since MMCs, like other cryogenic γ-detector technologies with operating temperatures <0.1 K, are intrinsically slow and have to be small for high resolution, special emphasis will be placed on questions that determine sensitivity and the potential for scaling to arrays. Objectives for FY14 were therefore to fabricate an improved version of MMC γ-detectors and test their energy resolution, maximum count rate, readout noise, crosstalk between pixels and linearity.

  3. A Pilot Study of Contextual UMLS Indexing to Improve the Precision of Concept-based Representation in XML-structured Clinical Radiology Reports

    PubMed Central

    Huang, Yang; Lowe, Henry J.; Hersh, William R.

    2003-01-01

    Objective: Despite the advantages of structured data entry, much of the patient record is still stored as unstructured or semistructured narrative text. The issue of representing clinical document content remains problematic. The authors' prior work using an automated UMLS document indexing system has been encouraging but has been affected by the generally low indexing precision of such systems. In an effort to improve precision, the authors have developed a context-sensitive document indexing model to calculate the optimal subset of UMLS source vocabularies used to index each document section. This pilot study was performed to evaluate the utility of this indexing approach on a set of clinical radiology reports. Design: A set of clinical radiology reports that had been indexed manually using UMLS concept descriptors was indexed automatically by the SAPHIRE indexing engine. Using the data generated by this process the authors developed a system that simulated indexing, at the document section level, of the same document set using many permutations of a subset of the UMLS constituent vocabularies. Measurements: The precision and recall scores generated by simulated indexing for each permutation of two or three UMLS constituent vocabularies were determined. Results: While there was considerable variation in precision and recall values across the different subtypes of radiology reports, the overall effect of this indexing strategy using the best combination of two or three UMLS constituent vocabularies was an improvement in precision without significant impact of recall. Conclusion: In this pilot study a contextual indexing strategy improved overall precision in a set of clinical radiology reports. PMID:12925544

  4. Precision analysis of electron energy spectrum and angular distribution of neutron β- decay with polarized neutron and electron

    NASA Astrophysics Data System (ADS)

    Ivanov, A. N.; Höllwieser, R.; Troitskaya, N. I.; Wellenzohn, M.; Berdnikov, Ya. A.

    2017-05-01

    We give a precision analysis of the correlation coefficients of the electron energy spectrum and angular distribution of the β- decay and radiative β- decay of the neutron with polarized neutron and electron to order 10-3. The calculation of correlation coefficients is carried out within the standard model, with contributions of order 10-3 caused by the weak magnetism and proton recoil taken to next-to-leading order in the large proton mass expansion, and with radiative corrections of order α /π ˜10-3 calculated to leading order in the large proton mass expansion. The obtained results can be used for the planning of experiments on the search for contributions of order 10-4 of interactions beyond the standard model.

  5. Mechanical properties and cell-culture characteristics of a polycaprolactone kagome-structure scaffold fabricated by a precision extruding deposition system.

    PubMed

    Lee, Se-Hwan; Cho, Yong Sang; Hong, Myoung Wha; Lee, Bu-Kyu; Park, Yongdoo; Park, Sang-Hyug; Kim, Young Yul; Cho, Young-Sam

    2017-09-13

    To enhance the mechanical properties of three-dimensional (3D) scaffolds used for bone regeneration in tissue engineering, many researchers have studied their structure and chemistry. In the structural engineering field, the kagome structure has been known to have an excellent relative strength. In this study, to enhance the mechanical properties of a synthetic polymer scaffold used for tissue engineering, we applied the 3D kagome structure to a porous scaffold for bone regeneration. Prior to fabricating the biocompatible-polymer scaffold, the ideal kagome structure, which was manufactured by a 3D printer of the digital light processing type, was compared with a grid-structure, which was used as the control group, using a compressive experiment. A polycaprolactone (PCL) kagome-structure scaffold was successfully fabricated by additive manufacturing using a 3D printer with a precision extruding deposition head. To assess the physical characteristics of the fabricated PCL-kagome-structure scaffold, we analyzed its porosity, pore size, morphological structure, surface roughness, compressive stiffness, and mechanical bending properties. The results showed that, the mechanical properties of proposed kagome-structure scaffold were superior to those of a grid-structure scaffold. Moreover, Sarcoma osteogenic (Saos-2) cells were used to evaluate the characteristics of in vitro cell proliferation. We carried out cell counting kit-8 (CCK-8) and DNA contents assays. Consequently, the cell proliferation of the kagome-structure scaffold was increased; this could be because the surface roughness of the kagome-structure scaffold enhances initial cell attachment.

  6. Linear precision inertial actuator built for low-impact in-situ installation on structures with vibration problems

    NASA Astrophysics Data System (ADS)

    Updike, Clark A.; Greeley, Scott W.; King, James A.

    1998-10-01

    In the process of designing a control actuator for a vibration cancellation system demonstration on a large, precision optical testbed, it was discovered that the support struts on which the control actuators attach could not be disassembled. This led to the development of a Linear Precision ACTuator (LPACT) with a novel two piece design which could be clamped around the strut in-situ. The design requirements, LPACT characteristics, and LPACT test results are fully described and contrasted with other earlier LPACT designs. Cancellation system performance results are presented for a 3 tone disturbance case. Excellent results, on the order of 40 dB of attenuation per tone (down to the noise floor on two disturbances), are achieved using an Adaptive Neural Controller (ANC).

  7. A precise method for the analysis of d18O of dissolved inorganic phosphate in seawater

    USGS Publications Warehouse

    McLaughlin, K.; Silva, S.; Kendall, C.; Stuart-Williams, Hilary; Paytan, A.

    2004-01-01

    A method for preparation and analysis of the oxygen isotope composition (d18O) of dissolved inorganic phosphate (DIP) has been developed and preliminary results for water samples from various locations are reported. Phosphate is extracted from seawater samples by coprecipitation with magnesium hydroxide. Phosphate is further purified through a series of precipitations and resin separation and is ultimately converted to silver phosphate. Silver phosphate samples are pyrolitically decomposed to carbon monoxide and analyzed for d18O. Silver phosphate samples weighing 0.7 mg (3.5 mol oxygen) can be analyzed routinely with an average standard deviation of about 0.3. There is no isotope fractionation during extraction and blanks are negligible within analytical error. Reproducibility was determined for both laboratory standards and natural samples by multiple analyses. A comparison between filtered and unfiltered natural seawater samples was also conducted and no appreciable difference was observed for the samples tested. The d18O values of DIP in seawater determined using this method range from 18.6 to 22.3, suggesting small but detectable natural variability in seawater. For the San Francisco Bay estuary DIP d18O is more variable, ranging from 11.4 near the San Joaquin River to 20.1 near the Golden Gate Bridge, and was well correlated with salinity, phosphate concentration, and d18O of water.

  8. In vacuo reduction of silver orthophosphate with graphite for high-precision oxygen isotope analysis.

    PubMed

    Pelc, Andrzej; Halas, Stanislaw

    2010-10-15

    The reduction of silver phosphate with graphite under vacuum conditions was studied at final reaction temperatures varying from 430 to 915°C to determine: (i) the CO(2) extraction yield, and (ii) the oxygen isotopic composition of CO(2). The CO(2) yield and oxygen isotopic composition were determined on a calibrated dual inlet and triple collector isotope ratio mass spectrometer. We observed the following three stages of the reduction process. (1) At temperatures below 590°C only CO(2) is formed, while silver orthophosphate decays to pyrophosphate. (2) At higher temperatures, 590-830°C, predominantly CO is formed from silver pyrophosphate which decays to metaphosphate; this CO was always converted into CO(2) by the glow discharge method. (3) At temperatures above 830°C the noticeable sublimation of silver orthophosphate occurs. This observation was accompanied by the oxygen isotope analysis of the obtained CO(2). The measured δ(18)O value varied from -11.93‰ (at the lowest temperature) to -20.32‰ (at the highest temperature). The optimum reduction temperature range was found to be 780-830°C. In this temperature range the oxygen isotopic composition of CO(2) is nearly constant and the reaction efficiency is relatively high. The determined difference between the δ(18)O value of oxygen in silver phosphate and that in CO(2) extracted from this phosphate is +0.70‰. Copyright © 2010 John Wiley & Sons, Ltd.

  9. Isolation and genetic analysis of pure cells from forensic biological mixtures: The precision of a digital approach.

    PubMed

    Fontana, F; Rapone, C; Bregola, G; Aversa, R; de Meo, A; Signorini, G; Sergio, M; Ferrarini, A; Lanzellotto, R; Medoro, G; Giorgini, G; Manaresi, N; Berti, A

    2017-07-01

    Latest genotyping technologies allow to achieve a reliable genetic profile for the offender identification even from extremely minute biological evidence. The ultimate challenge occurs when genetic profiles need to be retrieved from a mixture, which is composed of biological material from two or more individuals. In this case, DNA profiling will often result in a complex genetic profile, which is then subject matter for statistical analysis. In principle, when more individuals contribute to a mixture with different biological fluids, their single genetic profiles can be obtained by separating the distinct cell types (e.g. epithelial cells, blood cells, sperm), prior to genotyping. Different approaches have been investigated for this purpose, such as fluorescent-activated cell sorting (FACS) or laser capture microdissection (LCM), but currently none of these methods can guarantee the complete separation of different type of cells present in a mixture. In other fields of application, such as oncology, DEPArray™ technology, an image-based, microfluidic digital sorter, has been widely proven to enable the separation of pure cells, with single-cell precision. This study investigates the applicability of DEPArray™ technology to forensic samples analysis, focusing on the resolution of the forensic mixture problem. For the first time, we report here the development of an application-specific DEPArray™ workflow enabling the detection and recovery of pure homogeneous cell pools from simulated blood/saliva and semen/saliva mixtures, providing full genetic match with genetic profiles of corresponding donors. In addition, we assess the performance of standard forensic methods for DNA quantitation and genotyping on low-count, DEPArray™-isolated cells, showing that pure, almost complete profiles can be obtained from as few as ten haploid cells. Finally, we explore the applicability in real casework samples, demonstrating that the described approach provides complete

  10. [Development of HPLC with high-sensitive and precise electrochemical detection enabling dynamic analysis of compounds of biological importance].

    PubMed

    Kotani, Akira

    2012-01-01

    HPLC with electrochemical detection (HPLC-ECD) is an attractive method with sensitivity and selectivity for the determination of redox compounds. However, an improper system makeup or operation is apt not to show such the intrinsic characteristics of the analytical results by HPLC-ECD in regards to biological sample assays. In this review, HPLC-ECD enabling high-sensitive and precise analysis of compounds of biological importance was developed using the following chemometric strategies: spectrum analysis of chromatographic baseline noise, standard deviation (S.D.) of area measurements in baseline noise from stochastic aspects, and optimization of HPLC conditions and method validations in HPLC-ECD using the prediction of precision based on the FUMI (Function of Mutual Information) theory. When HPLC-ECD was established using a capillary column (0.2 mm i.d.), catechins were determined at attomole levels and the present HPLC-ECD was applied to the determination of concentration profiles of catechins in human plasma after green tea ingestion. Moreover, two HPLC-ECD systems for determining acids and bases were developed by the means of the voltammetric reduction of quinone and the oxidation of trolox, respectively. Thus, the application of HPLC-ECD methods has been remarkably expanded through the development of novel ECD for the determination of acids and bases which are less active electrochemically. The present methods for determining acids and bases were applied to the pharmacokinetic studies of free fatty acids and theophylline, respectively. In conclusion, it was shown the present HPLC-ECD methods have been successfully applied to biomedical and pharmaceutical analyses.

  11. How Precise Are Preinterventional Measurements Using Centerline Analysis Applications? Objective Ground Truth Evaluation Reveals Software-Specific Centerline Characteristics.

    PubMed

    Hoegen, Philipp; Wörz, Stefan; Müller-Eschner, Matthias; Geisbüsch, Philipp; Liao, Wei; Rohr, Karl; Schmitt, Matthias; Rengier, Fabian; Kauczor, Hans-Ulrich; von Tengg-Kobligk, Hendrik

    2017-08-01

    To evaluate different centerline analysis applications using objective ground truth from realistic aortic aneurysm phantoms with precisely defined geometry and centerlines to overcome the lack of unknown true dimensions in previously published in vivo validation studies. Three aortic phantoms were created using computer-aided design (CAD) software and a 3-dimensional (3D) printer. Computed tomography angiograms (CTAs) of phantoms and 3 patients were analyzed with 3 clinically approved and 1 research software application. The 3D centerline coordinates, intraluminal diameters, and lengths were validated against CAD ground truth using a dedicated evaluation software platform. The 3D centerline position mean error ranged from 0.7±0.8 to 2.9±2.5 mm between tested applications. All applications calculated centerlines significantly different from ground truth. Diameter mean errors varied from 0.5±1.2 to 1.1±1.0 mm among 3 applications, but exceeded 8.0±11.0 mm with one application due to an unsteady distortion of luminal dimensions along the centerline. All tested commercially available software tools systematically underestimated centerline total lengths by -4.6±0.9 mm to -10.4±4.3 mm (maximum error -14.6 mm). Applications with the highest 3D centerline accuracy yielded the most precise diameter and length measurements. One clinically approved application did not provide reproducible centerline-based analysis results, while another approved application showed length errors that might influence stent-graft choice and procedure success. The variety and specific characteristics of endovascular aneurysm repair planning software tools require scientific evaluation and user awareness.

  12. mMass 3: a cross-platform software environment for precise analysis of mass spectrometric data.

    PubMed

    Strohalm, Martin; Kavan, Daniel; Novák, Petr; Volný, Michael; Havlícek, Vladimír

    2010-06-01

    While tools for the automated analysis of MS and LC-MS/MS data are continuously improving, it is still often the case that at the end of an experiment, the mass spectrometrist will spend time carefully examining individual spectra. Current software support is mostly provided only by the instrument vendors, and the available software tools are often instrument-dependent. Here we present a new generation of mMass, a cross-platform environment for the precise analysis of individual mass spectra. The software covers a wide range of processing tasks such as import from various data formats, smoothing, baseline correction, peak picking, deisotoping, charge determination, and recalibration. Functions presented in the earlier versions such as in silico digestion and fragmentation were redesigned and improved. In addition to Mascot, an interface for ProFound has been implemented. A specific tool is available for isotopic pattern modeling to enable precise data validation. The largest available lipid database (from the LIPID MAPS Consortium) has been incorporated and together with the new compound search tool lipids can be rapidly identified. In addition, the user can define custom libraries of compounds and use them analogously. The new version of mMass is based on a stand-alone Python library, which provides the basic functionality for data processing and interpretation. This library can serve as a good starting point for other developers in their projects. Binary distributions of mMass, its source code, a detailed user's guide, and video tutorials are freely available from www.mmass.org .

  13. Crash Simulation and Nonlinear Structural Analysis

    NASA Technical Reports Server (NTRS)

    Kamat, M. P.

    1984-01-01

    Behavior of structures composed of trusses, frames and membranes modeled. Crash simulation analysis useful in developing understanding of multifaceted relationship between complex structural configuration, such as aircraft, and response during crash. CDC version written in FORTRAN IV.

  14. Modeling, Analysis, and Optimization Issues for Large Space Structures

    NASA Technical Reports Server (NTRS)

    Pinson, L. D. (Compiler); Amos, A. K. (Compiler); Venkayya, V. B. (Compiler)

    1983-01-01

    Topics concerning the modeling, analysis, and optimization of large space structures are discussed including structure-control interaction, structural and structural dynamics modeling, thermal analysis, testing, and design.

  15. Structural analysis considerations for wind turbine blades

    NASA Technical Reports Server (NTRS)

    Spera, D. A.

    1979-01-01

    Approaches to the structural analysis of wind turbine blade designs are reviewed. Specifications and materials data are discussed along with the analysis of vibrations, loads, stresses, and failure modes.

  16. Precision Muonium Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jungmann, Klaus P.

    2016-09-01

    The muonium atom is the purely leptonic bound state of a positive muon and an electron. It has a lifetime of 2.2 µs. The absence of any known internal structure provides for precision experiments to test fundamental physics theories and to determine accurate values of fundamental constants. In particular ground state hyperfine structure transitions can be measured by microwave spectroscopy to deliver the muon magnetic moment. The frequency of the 1s-2s transition in the hydrogen-like atom can be determined with laser spectroscopy to obtain the muon mass. With such measurements fundamental physical interactions, in particular quantum electrodynamics, can also be tested at highest precision. The results are important input parameters for experiments on the muon magnetic anomaly. The simplicity of the atom enables further precise experiments, such as a search for muonium-antimuonium conversion for testing charged lepton number conservation and searches for possible antigravity of muons and dark matter.

  17. Application of high precision band structure calculations to the equation of state for beryllium oxide: SESAME equation of state number 7612

    SciTech Connect

    Boettger, J.C.; Wills, J.M.

    1992-03-01

    High precision electronic band structure calculations for BeO have revealed a large volume discontinuity structural phase transition on the 0 K isotherm at about 1 Mbar. Although, this transition has not been observed experimentally, the accuracy of the calculations is such that the existence of this transition is unambiguous. A transition of this magnitude is likely to have a substantial impact on hydrodynamic simulations involving BeO. Here we report the creation of a new SESAME equations of state for BeO which incorporates the effect of the theoretically determined phase transition. This new EOS will be added to the SESAME library as material number 7612.

  18. Application of high precision band structure calculations to the equation of state for beryllium oxide: SESAME equation of state number 7612

    SciTech Connect

    Boettger, J.C.; Wills, J.M.

    1992-03-01

    High precision electronic band structure calculations for BeO have revealed a large volume discontinuity structural phase transition on the 0 K isotherm at about 1 Mbar. Although, this transition has not been observed experimentally, the accuracy of the calculations is such that the existence of this transition is unambiguous. A transition of this magnitude is likely to have a substantial impact on hydrodynamic simulations involving BeO. Here we report the creation of a new SESAME equations of state for BeO which incorporates the effect of the theoretically determined phase transition. This new EOS will be added to the SESAME library as material number 7612.

  19. USNO Analysis Center for Source Structure Report

    DTIC Science & Technology

    2013-06-01

    United States Naval Observatory USNO Analysis Center for Source Structtue USNO Analysis Center for Source Structure Report Alan L. Fey, David A...Boboltz, Ralph A. Gaume Abstract This report summarizes the activities of the United States Naval Observatory Analysis Center for Source Structure...supported and operated by the United States Naval Observatory (USNO). The charter of the Analysis Center is to provide products directly related to the

  20. Precise coregistration, stationary and non-stationary azimuth offsets and challenges for TOPS time-series analysis

    NASA Astrophysics Data System (ADS)

    Fattahi, H.; Agram, P. S.; Simons, M.

    2016-12-01

    Time-series analysis of Synthetic Aperture Radar (SAR) images acquired with Terrain Observation with Progressive Scan (TOPS) mode requires precise coregistration of a stack of TOPS images to a reference coordinate system with accuracies better than 0.001 pixel in azimuth direction. This accuracy is an order of magnitude larger than the achievable accuracy using geometry based coregistration techniques with satellite precise orbits and Digital Elevation Models. To avoid phase discontinuities at the regions of burst overlap in TOPS interferograms, azimuth offsets obtained with geometry-based techniques need to be refined for possible misregistration. In the case of stationary azimuth misregistration (i.e., constant azimuth misregistration or slowly varying misregistration in the azimuth direction), Enhanced Spectral Diversity (ESD) technique can be used to adjust the azimuth offsets precisely and achieve coregistration accuracies better than 0.001 of an azimuth cell. We present an approach to estimate a time-series of azimuth misregistration using a Network-based Enhanced Spectral Diversity (NESD) method that reduces the impact of temporal decorrelation on coregistration. We evaluate the NESD performance using different stacks of TOPS images acquired by Sentinel-1 over different regions. Standard deviation of the estimated misregistration time-series for different stacks varies from 1.1e-3 to 2e-3 of the azimuth resolution, equivalent to 1.6 to 2.8 cm orbital uncertainty in azimuth direction. These values fall within the 1-sigma orbital uncertainty of the Sentinel-1 orbits and imply that orbital uncertainty is most likely the main source of the constant azimuth misregistration between different TOPS acquisitions. We further discuss the sources of non-stationary azimuth misregistration (i.e., azimuth misregistration which varies significantly in range or azimuth direction) and possible solutions to overcome these difficulties. We demonstrate how deviation of the SAR

  1. Precision atomic spectroscopy for improved limits on variation of the fine structure constant and local position invariance.

    PubMed

    Fortier, T M; Ashby, N; Bergquist, J C; Delaney, M J; Diddams, S A; Heavner, T P; Hollberg, L; Itano, W M; Jefferts, S R; Kim, K; Levi, F; Lorini, L; Oskay, W H; Parker, T E; Shirley, J; Stalnaker, J E

    2007-02-16

    We report tests of local position invariance and the variation of fundamental constants from measurements of the frequency ratio of the 282-nm 199Hg+ optical clock transition to the ground state hyperfine splitting in 133Cs. Analysis of the frequency ratio of the two clocks, extending over 6 yr at NIST, is used to place a limit on its fractional variation of <5.8x10(-6) per change in normalized solar gravitational potential. The same frequency ratio is also used to obtain 20-fold improvement over previous limits on the fractional variation of the fine structure constant of |alpha/alpha|<1.3x10(-16) yr-1, assuming invariance of other fundamental constants. Comparisons of our results with those previously reported for the absolute optical frequency measurements in H and 171Yb+ vs other 133Cs standards yield a coupled constraint of -1.5x10(-15)

  2. Japanese structure survey of high-precision radiotherapy in 2012 based on institutional questionnaire about the patterns of care.

    PubMed

    Tomita, Natsuo; Kodaira, Takeshi; Teshima, Teruki; Ogawa, Kazuhiko; Kumazaki, Yu; Yamauchi, Chikako; Toita, Takafumi; Uno, Takashi; Sumi, Minako; Onishi, Hiroshi; Kenjo, Masahiro; Nakamura, Katsumasa

    2014-06-01

    The purpose of this study was to clarify operational situations, treatment planning and processes, quality assurance and quality control with relevance to stereotactic radiotherapy, intensity-modulated radiotherapy and image-guided radiotherapy in Japan. We adopted 109 items as the quality indicators of high-precision radiotherapy to prepare a questionnaire. In April 2012, we started to publicly open the questionnaire on the website, requesting every institution with radiotherapy machines for response. The response ratio was 62.1% (490 out of 789 institutions responded). Two or more radiotherapy technologists per linear accelerator managed linear accelerator operation in ∼90% of the responded institutions while medical physicists/radiotherapy quality managers were engaged in the operation in only 64.9% of the institutions. Radiotherapy certified nurses also worked in only 18.4% of the institutions. The ratios of the institutions equipped for stereotactic radiotherapy of lung tumor, intensity-modulated radiotherapy and image-guided radiotherapy were 43.3, 32.6 and 46.8%, respectively. In intensity-modulated radiotherapy planning, radiation oncologists were usually responsible for delineation while medical physicists/radiotherapy quality managers or radiotherapy technologists set up beam in 33.3% of the institutions. The median time required for quality assurance of intensity-modulated radiotherapy at any site of brain, head and neck and prostate was 4 h. Intensity-modulated radiotherapy quality assurance activity had to be started after clinical hours in >60% of the institutions. This study clarified one major issue in the current high-precision radiotherapy in Japan. A manpower shortage should be corrected for high-precision radiotherapy, especially in the area relevant to quality assurance/quality control. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Comparative classification analysis of post-harvest growth detection from terrestrial LiDAR point clouds in precision agriculture

    NASA Astrophysics Data System (ADS)

    Koenig, Kristina; Höfle, Bernhard; Hämmerle, Martin; Jarmer, Thomas; Siegmann, Bastian; Lilienthal, Holger

    2015-06-01

    In precision agriculture, detailed geoinformation on plant and soil properties plays an important role, e.g., in crop protection or the application of fertilizers. This paper presents a comparative classification analysis for post-harvest growth detection using geometric and radiometric point cloud features of terrestrial laser scanning (TLS) data, considering the local neighborhood of each point. Radiometric correction of the TLS data was performed via an empirical range-correction function derived from a field experiment. Thereafter, the corrected amplitude and local elevation features were explored regarding their importance for classification. For the comparison, tree induction, Naive Bayes, and k-Means-derived classifiers were tested for different point densities to distinguish between ground and post-harvest growth. The classification performance was validated against highly detailed RGB reference images and the red edge normalized difference vegetation index (NDVI705), derived from a hyperspectral sensor. Using both geometric and radiometric features, we achieved a precision of 99% with the tree induction. Compared to the reference image classification, the calculated post-harvest growth coverage map reached an accuracy of 80%. RGB and LiDAR-derived coverage showed a polynomial correlation to NDVI705 of degree two with R2 of 0.8 and 0.7, respectively. Larger post-harvest growth patches (>10 × 10 cm) could already be detected by a point density of 2 pts./0.01 m2. The results indicate a high potential of radiometric and geometric LiDAR point cloud features for the identification of post-harvest growth using tree induction classification. The proposed technique can potentially be applied over larger areas using vehicle-mounted scanners.

  4. Real-time analysis of δ13C- and δD-CH4 by high precision laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Eyer, Simon; Emmenegger, Lukas; Tuzson, Béla; Fischer, Hubertus; Mohn, Joachim

    2014-05-01

    Methane (CH4) is the most important non-CO2 greenhouse gas (GHG) contributing 18% to total radiative forcing. Anthropogenic sources (e.g. ruminants, landfills) contribute 60% to total emissions and led to an increase in its atmospheric mixing ratio from 700 ppb in pre-industrial times to 1819 ± 1 ppb in 2012 [1]. Analysis of the most abundant methane isotopologues 12CH4, 13CH4 and 12CH3D can be used to disentangle the various source/sink processes [2] and to develop target oriented reduction strategies. High precision isotopic analysis of CH4 can be accomplished by isotope-ratio mass-spectrometry (IRMS) [2] and more recently by mid-infrared laser-based spectroscopic techniques. For high precision measurements in ambient air, however, both techniques rely on preconcentration of the target gas [3]. In an on-going project, we developed a fully-automated, field-deployable CH4 preconcentration unit coupled to a dual quantum cascade laser absorption spectrometer (QCLAS) for real-time analysis of CH4 isotopologues. The core part of the rack-mounted (19 inch) device is a highly-efficient adsorbent trap attached to a motorized linear drive system and enclosed in a vacuum chamber. Thereby, the adsorbent trap can be decoupled from the Stirling cooler during desorption for fast desorption and optimal heat management. A wide variety of adsorbents, including: HayeSep D, molecular sieves as well as the novel metal-organic frameworks and carbon nanotubes were characterized regarding their surface area, isosteric enthalpy of adsorption and selectivity for methane over nitrogen. The most promising candidates were tested on the preconcentration device and a preconcentration by a factor > 500 was obtained. Furthermore analytical interferants (e.g. N2O, CO2) are separated by step-wise desorption of trace gases. A QCL absorption spectrometer previously described by Tuzson et al. (2010) for CH4 flux measurements was modified to obtain a platform for high precision and simultaneous

  5. Precise 3D Lug Pose Detection Sensor for Automatic Robot Welding Using a Structured-Light Vision System

    PubMed Central

    Park, Jae Byung; Lee, Seung Hun; Lee, Il Jae

    2009-01-01

    In this study, we propose a precise 3D lug pose detection sensor for automatic robot welding of a lug to a huge steel plate used in shipbuilding, where the lug is a handle to carry the huge steel plate. The proposed sensor consists of a camera and four laser line diodes, and its design parameters are determined by analyzing its detectable range and resolution. For the lug pose acquisition, four laser lines are projected on both lug and plate, and the projected lines are detected by the camera. For robust detection of the projected lines against the illumination change, the vertical threshold, thinning, Hough transform and separated Hough transform algorithms are successively applied to the camera image. The lug pose acquisition is carried out by two stages: the top view alignment and the side view alignment. The top view alignment is to detect the coarse lug pose relatively far from the lug, and the side view alignment is to detect the fine lug pose close to the lug. After the top view alignment, the robot is controlled to move close to the side of the lug for the side view alignment. By this way, the precise 3D lug pose can be obtained. Finally, experiments with the sensor prototype are carried out to verify the feasibility and effectiveness of the proposed sensor. PMID:22400007

  6. RNA Bioinformatics for Precision Medicine.

    PubMed

    Chen, Jiajia; Shen, Bairong

    2016-01-01

    The high-throughput transcriptomic data generated by deep sequencing technologies urgently require bioinformatics methods for proper data visualization, analysis, storage, and interpretation. The involvement of noncoding RNAs in human diseases highlights their potential as biomarkers and therapeutic targets to facilitate the precision medicine. In this chapter, we give a brief overview of the bioinformatics tools to analyze different aspects of RNAs, in particular ncRNAs. We first describe the emerging bioinformatics methods for RNA identification, structure modeling, functional annotation, and network inference. This is followed by an introduction of potential usefulness of ncRNAs as diagnostic, prognostic biomarkers and therapeutic strategies.

  7. Precise ERBB2 copy number assessment in breast cancer by means of molecular inversion probe array analysis.

    PubMed

    Christgen, Matthias; van Luttikhuizen, Jana L; Raap, Mieke; Braubach, Peter; Schmidt, Lars; Jonigk, Danny; Feuerhake, Friedrich; Lehmann, Ulrich; Schlegelberger, Brigitte; Kreipe, Hans H; Steinemann, Doris

    2016-12-13

    HER2/ERBB2 amplification/overexpression determines the eligibility of breast cancer patients to HER2-targeted therapy. This study evaluates the agreement between ERBB2 copy number assessment by fluorescence in situ hybridization, a standard method recommended by the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP), and newly available DNA extraction-based methods. A series of n=29 formalin-fixed paraffin-embedded breast cancers were subjected to ERBB2 copy number assessment by fluorescence in situ hybridization (FISH, Vysis, Abbott). Following macrodissection of invasive breast cancer tissue and DNA extraction, ERBB2 copy number was also determined by molecular inversion probe array analysis (MIP, OncoScan, Affymetrix) and next generation sequencing combined with normalized amplicon coverage analysis (NGS/NAC, AmpliSeq, Ion Torrent). ERBB2 copy number values obtained by MIP or NGS/NAC were tightly correlated with ERBB2 copy number values obtained by conventional FISH (rs = 0.940 and rs = 0.894, P < 0.001). Using ASCO/CAP guideline-conform thresholds for categorization of breast cancers as HER2-negative, equivocal or positive, nearly perfect concordance was observed for HER2 classification by FISH and MIP (93% concordant classifications, κ = 0.87). Substantial concordance was observed for FISH and NGS/NAC (83% concordant classifications, κ = 0.62). In conclusion, MIP facilitates precise ERBB2 copy number detection and should be considered as an ancillary method for clinical HER2 testing.

  8. NASA Structural Analysis System (NASTRAN)

    NASA Technical Reports Server (NTRS)

    Purves, L.

    1991-01-01

    Program aids in structural design of wide range of objects, from high-impact printer parts to turbine engine blades, and fully validated. Since source code included, NASTRAN modified or enhanced for new applications.

  9. Precision cosmological parameter estimation

    NASA Astrophysics Data System (ADS)

    Fendt, William Ashton, Jr.

    2009-09-01

    Experimental efforts of the last few decades have brought. a golden age to mankind's endeavor to understand tine physical properties of the Universe throughout its history. Recent measurements of the cosmic microwave background (CMB) provide strong confirmation of the standard big bang paradigm, as well as introducing new mysteries, to unexplained by current physical models. In the following decades. even more ambitious scientific endeavours will begin to shed light on the new physics by looking at the detailed structure of the Universe both at very early and recent times. Modern data has allowed us to begins to test inflationary models of the early Universe, and the near future will bring higher precision data and much stronger tests. Cracking the codes hidden in these cosmological observables is a difficult and computationally intensive problem. The challenges will continue to increase as future experiments bring larger and more precise data sets. Because of the complexity of the problem, we are forced to use approximate techniques and make simplifying assumptions to ease the computational workload. While this has been reasonably sufficient until now, hints of the limitations of our techniques have begun to come to light. For example, the likelihood approximation used for analysis of CMB data from the Wilkinson Microwave Anistropy Probe (WMAP) satellite was shown to have short falls, leading to pre-emptive conclusions drawn about current cosmological theories. Also it can he shown that an approximate method used by all current analysis codes to describe the recombination history of the Universe will not be sufficiently accurate for future experiments. With a new CMB satellite scheduled for launch in the coming months, it is vital that we develop techniques to improve the analysis of cosmological data. This work develops a novel technique of both avoiding the use of approximate computational codes as well as allowing the application of new, more precise analysis

  10. Detecting Mantle Heterogeneity at a Grain Scale with Improvements in High Precision Neodymium Isotope (NdO+) Analysis

    NASA Astrophysics Data System (ADS)

    Honn, D.; Harvey, J.; Warren, J. M.; Baxter, E. F.

    2013-12-01

    Recent advances in the analysis of Nd isotopes by thermal ionization mass spectrometry (TIMS) as an oxide[1,2] have led to significant improvements in our ability to measure small aliquots of Nd (e.g. 4 ng) to high levels of precision (10 ppm, 2 RSD). In one resulting application, the age precision achievable in garnet geochronology has been significantly improved, allowing the dating of multiple zones of an individual garnet to a resolution of × 0.5 Ma [2]. More recently, the methods described in [1] have been further improved upon, allowing 400 pg loads of Nd to be run at 25-50 ppm (2 RSE) precision. The ability to precisely analyse sub-ng aliquots of Nd opens up a whole new range of possible applications for this method. Chemical and isotopic heterogeneity in the Earth's mantle has been identified at a number of scales[3][4]. In particular, Nd isotope heterogeneity in abyssal peridotites has been recorded at a cm to km scale, revealing refractory domains of mantle Nd that are not readily observable in the basalts that they produce[5]. Here we present the preliminary results of experiments to determine the viability of single-grain (sub-mg) clinopyroxene analyses of Nd isotope measurements, with the goal of applying this method to the search for Nd isotope heterogeneity in mantle rocks on a cm scale. Optically pure clinopyroxene grains from a single peridotite xenolith from Kilbourne Hole, New Mexico[6] were hand-picked under a binocular microscope prior to purification for Nd isotope analyses using methods described in [1]. The internal reproducibility of unleached batches of 16, 8, 4 and 2 grains of clinopyroxene (<23 ppm, 2 RSE) is smaller than the degree of heterogeneity observed between the different populations of grains (>145 ppm). When single grains of clinopyroxene (0.4 - 1.2 mg) were leached in 1.5M HCl for 30 minutes at 80 degrees C and analysed, the degree of heterogeneity observed between grains was even greater (≤303 ppm) compared to the internal

  11. A Precision Measurement of the Spin Structure Functions f^p_1 and g^g_1

    SciTech Connect

    Toole, T.

    2004-12-13

    In Experiment E155 at the Stanford Linear Accelerator Center, the spin dependent structure function g{sub 1}(x,Q{sup 2}) was measured for both the proton and deuteron. This was accomplished by scattering 48.3 GeV highly polarized electrons (0.813 {+-} 0.020) off polarized {sup 15}NH{sub 3} (proton) and {sup 6}LiD (deuteron) targets. Data were collected in March and April of 1997 using three fixed angle, momentum analyzing spectrometers centered at 2.75{sup o}, 5.5{sup o}, and 10.5{sup o}. This enabled a kinematic coverage of 0.01 < x < 0.9 and 1 GeV{sup 2} < Q{sup 2} < 40 GeV{sup 2}. At an average Q{sup 2} of 5 GeV{sup 2}, the integrals in the measured region were f{sub 0.014}{sup 0.9}g{sub 1}(x)dx = 0.119 {+-} 0.002(stat.) {+-} 0.009(syst.) for the proton and 0.043 {+-} 0.003(stat.) {+-} 0.003(syst.) for the deuteron. Using a perturbative QCD analysis which included a global data set, the results were found to be consistent with the Bjorken Sum Rule. Asymmetry measurements also were made using photoproduced hadrons. Data were collected concurrently with the g{sub 1} data. For the proton, the asymmetries were small and non-zero. The deuteron measurements were consistent with zero.

  12. Fourier Analysis and Structure Determination--Part III: X-ray Crystal Structure Analysis.

    ERIC Educational Resources Information Center

    Chesick, John P.

    1989-01-01

    Discussed is single crystal X-ray crystal structure analysis. A common link between the NMR imaging and the traditional X-ray crystal structure analysis is reported. Claims that comparisons aid in the understanding of both techniques. (MVL)

  13. Computer applications for engineering/structural analysis

    SciTech Connect

    Zaslawsky, M.; Samaddar, S.K.

    1991-01-01

    Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequences of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.

  14. Structural analysis techniqes for remote sensing

    NASA Technical Reports Server (NTRS)

    Shapiro, L. G.

    1982-01-01

    The structural analysis of remotely sensed imagery is defined and basic techniques for implementing the process are described. Structural analysis uses knowledge of the properties of an entity, its parts and their relationships, and the relationships in which it participates at a higher level to locate and recognize objects in a visual scene. The representation of structural knowledge, the development of algorithms for using the knowledge to help analyze an image, and techniques for storage and retrieval of relational models are addressed.

  15. Continuous Flow - Cavity RingDown Spectroscopy Using a Novel Universal Interface for High-Precision Bulk 13C Analysis

    NASA Astrophysics Data System (ADS)

    Saad, Nabil; Richman, Bruce

    2010-05-01

    We have developed the world's first optical spectroscopy-based system for bulk stable isotope analysis of 13C. The system is based on a novel universal interface, named LIAISON, capable of coupling to almost any CO2-generating sample preparation front-end ranging from an elemental analyzer to any dissolved carbon analysis module, which are of significant use in geochemical, ecological and food authentication studies. In one specific application, we have coupled LIAISON to an elemental analyzer (EA) and to a cavity ring-down spectrometer (CRDS) for 13C isotopic analysis of adulterated honey samples. Another application was developed to analyze dissolved inorganic carbon in water samples. LIAISON is suited for handling a high-throughput sample analysis process by running three different gas handling operations in parallel: Admitting combustion gas from the EA into a first gas bellows, analyzing the previous sample collected into a second gas bellows with CRDS, and flushing and purging a third gas bellows in preparation for the upcoming sample collection operation. The sample-to-sample analysis time is 10 minutes and the operation is completely automated for the whole front-end auto-sampler tray capacity, requiring no operator intervention. The CRDS data are collected, tabulated and saved into an output text file. The memory effect between the USGS L-Glutamic acid standard at natural abundance and the moderately enriched USGS L-Glutamic acid standard is excluded by the selection of the adequate number and duration of flush and purge cycles of the gas sample bags. The system's proven accuracy was cross-checked with EA-IRMS and its achieved precision was typically less than 0.2 permil, including the 13C-enriched tested samples. The LIAISON-CRDS system presented here provides a fully automated solution for 13C bulk stable isotope analysis with unprecedented ease-of-use and possible field portability and application with the availability of a compact front-end. In

  16. A cryptic record of magma mixing in diorites revealed by high-precision SIMS oxygen isotope analysis of zircons

    NASA Astrophysics Data System (ADS)

    Appleby, S. K.; Graham, C. M.; Gillespie, M. R.; Hinton, R. W.; Oliver, G. J. H.; EIMF

    2008-05-01

    High-precision in-situ ion microprobe (SIMS) oxygen isotope analysis of zircons from two diorite intrusions associated with the late Caledonian Lochnagar pluton in Scotland has revealed large differences in the degree of heterogeneity in zircon δ18O between the diorites. Zircon crystals from the Cul nan Gad diorite (CnG) show a unimodal distribution of oxygen isotope values ( δ18O = 6.0 ± 0.6‰ (2 σ)) and no or only minor grain-scale variation. Those from the Allt Darrarie diorite (AD1) show a large range in δ18O and an apparent bimodal distribution with modes of 6.6 ± 0.4‰ and 7.3 ± 0.4‰. Variations of up to 1.2‰ occur between and within grains; both an increase and decrease in δ18O with zircon growth has been observed. The δ18O composition of growing zircon can only change if open-system processes affect the magma composition, i.e. if material of contrasting δ18O composition is added to the magma. The variability in AD1 is interpreted to represent a cryptic record of magma mixing. A 'deep crustal hot zone' is a likely site for generation of the dioritic magmas which developed by mixing of residual melts and crustal partial melts or by melting of mafic lower crustal rocks. The overall small number of zircons with mantle-like δ18O values (5.3 ± 0.6‰ (2 σ)) in the Lochnagar diorites is largely the product of crustal differentiation rather than crustal growth. The δ18O of quartz from the CnG and AD1 diorites shows only minor variation (CnG: 10.9 ± 0.5‰ (2 σ), AD1: 11.7 ± 0.6‰ (2 σ)) within single populations, with no evidence of mixing. Quartz-zircon isotopic disequilibrium is consistent with later crystallisation of quartz from late magmatic fluids, and in case of the AD1 diorite after the inferred magma mixing from a homogenised, higher δ18O melt. High-precision SIMS oxygen isotope analysis of zircon provides a new approach to identifying and resolving previously undetected early-stage magma mixing and constraining the compositions

  17. Precise Formation of a Hollow Carbon Nitride Structure with a Janus Surface To Promote Water Splitting by Photoredox Catalysis

    PubMed Central

    Zheng, Dandan; Cao, Xu‐Ning

    2016-01-01

    Abstract The precise modification of redox species on the inner and outer surfaces of hollow nanostructures is relevant in catalysis, surface science, and nanotechnology, but has proven difficult to achieve. Herein, we develop a facile approach to specifically fabricate Pt and Co3O4 nanoparticles (NPs) onto the interior and exterior surface of hollow carbon nitride spheres (HCNS), respectively, to promote the surface redox functions of the polymer semiconductors. The photocatalytic water splitting activities of HCNS with spatially separated oxidation and reduction centers at their nanodomains were enhanced. The origin of the enhanced activity was attributed to the spatially separated reactive sites for the evolution of H2 and O2 and also to the unidirectional migration of the electron and hole on the Janus surfaces, thereby preventing the unwanted reverse reaction of water splitting and decreasing charge recombination. PMID:27533739

  18. Structural analysis of ultra-high speed aircraft structural components

    NASA Technical Reports Server (NTRS)

    Lenzen, K. H.; Siegel, W. H.

    1977-01-01

    The buckling characteristics of a hypersonic beaded skin panel were investigated under pure compression with boundary conditions similar to those found in a wing mounted condition. The primary phases of analysis reported include: (1) experimental testing of the panel to failure; (2) finite element structural analysis of the beaded panel with the computer program NASTRAN; and (3) summary of the semiclassical buckling equations for the beaded panel under purely compressive loads. A comparison of each of the analysis methods is also included.

  19. Evaluation of qPCR curve analysis methods for reliable biomarker discovery: bias, resolution, precision, and implications.

    PubMed

    Ruijter, Jan M; Pfaffl, Michael W; Zhao, Sheng; Spiess, Andrej N; Boggy, Gregory; Blom, Jochen; Rutledge, Robert G; Sisti, Davide; Lievens, Antoon; De Preter, Katleen; Derveaux, Stefaan; Hellemans, Jan; Vandesompele, Jo

    2013-01-01

    algorithms' precision, bias, and resolution. While large differences exist between methods when considering the technical performance experiments, most methods perform relatively well on the biomarker data. The data and the analysis results per method are made available to serve as benchmark for further development and evaluation of qPCR curve analysis methods (http://qPCRDataMethods.hfrc.nl).

  20. Precisions on the structure of the Basque Arc (western Pyrenees, Spain): preliminary results from magnetic fabrics from the Biscay Synclinorium

    NASA Astrophysics Data System (ADS)

    Vegas, Néstor; Aranguren, Aitor; Rodríguez-Méndez, Lidia; Cuevas, Julia; María Tubía, José; Julián Esteban, José

    2017-04-01

    The Mesozoic Basque-Cantabrian basin (western Pyrenees) was inverted during the Alpine Orogeny in late Cretaceous-Eocene times. The central sector of the basin, the Basque Arc is characterized by the existence of large folds (80 km long) that outline an arc. This study focuses on the interpretation of AMS fabrics in rocks from the Biscay Synclinorium, a major fold system of the Basque Arc that verges to the NE, with sub-horizontal, N110˚ E trending axes and axial planes striking to N110˚ E and dipping steeply to the SW (Calvo-Rathert et al., 2007). The aim of this contribution is characterize the deformation around the Biscay Synclinorium. For this reason we combined fieldwork with magnetic fabric analysis of 95 cores in Upper Cretaceous sedimentary rocks of the Biscay Synclinorium. 68 cores come from the Calcareous formation (marls, sandy limestones and limestones of Cenomanian to Campanian age) that makes part of the northeastern limb of the synclinorium and the remaining 27 cores from the Detrital-calcareous flysch (a multilayer sequence with sandy limestones and marls of Maastrichtian age) that crops out in the synclinorium core (Garrote et al., 1991). In the Upper Cretaceous Calcareous formation there is a penetrative cleavage that mainly strikes to N110˚ E dipping 50˚ to 60˚ to the SW (S1). In the Detrital-calcareous flysch of the core, the best-preserved planar structure is the bedding and only locally an axial planar cleavage is observed. Intersection lineations are sub-horizontal and N110˚ E-trending. The measurements of the magnetic susceptibility provide low k values ranging between 99x10-6 and 403x10-6 SI. The anisotropy of the magnetic susceptibility, P, reaches values of 1.213, pointing to the overprinting of tectonic deformation on primary magnetic fabrics of sedimentary origin. The magnetic foliation shows a fairly uniform arrangement that is nearly coincident with the dominant planar structures of the rocks, S0 or S1in the core and the limb

  1. Precision in Stereochemical Terminology

    ERIC Educational Resources Information Center

    Wade, Leroy G., Jr.

    2006-01-01

    An analysis of relatively new terminology that has given multiple definitions often resulting in students learning principles that are actually false is presented with an example of the new term stereogenic atom introduced by Mislow and Siegel. The Mislow terminology would be useful in some cases if it were used precisely and correctly, but it is…

  2. Using Global Analysis to Extend the Accuracy and Precision of Binding Measurements with T cell Receptors and Their Peptide/MHC Ligands

    PubMed Central

    Blevins, Sydney J.; Baker, Brian M.

    2017-01-01

    In cellular immunity, clonally distributed T cell receptors (TCRs) engage complexes of peptides bound to major histocompatibility complex proteins (pMHCs). In the interactions of TCRs with pMHCs, regions of restricted and variable diversity align in a structurally complex fashion. Many studies have used mutagenesis to attempt to understand the “roles” played by various interface components in determining TCR recognition properties such as specificity and cross-reactivity. However, these measurements are often complicated or even compromised by the weak affinities TCRs maintain toward pMHC. Here, we demonstrate how global analysis of multiple datasets can be used to significantly extend the accuracy and precision of such TCR binding experiments. Application of this approach should positively impact efforts to understand TCR recognition and facilitate the creation of mutational databases to help engineer TCRs with tuned molecular recognition properties. We also show how global analysis can be used to analyze double mutant cycles in TCR-pMHC interfaces, which can lead to new insights into immune recognition. PMID:28197404

  3. Quantitative Thin-Film X-ray Microanalysis by STEM/HAADF: Statistical Analysis for Precision and Accuracy Determination

    NASA Astrophysics Data System (ADS)

    Armigliato, Aldo; Balboni, Roberto; Rosa, Rodolfo

    2006-07-01

    Silicon-germanium thin films have been analyzed by EDS microanalysis in a field emission gun scanning transmission electron microscope (FEG-STEM) equipped with a high angular dark-field detector (STEM/HAADF). Several spectra have been acquired in the same homogeneous area of the cross-sectioned sample by drift-corrected linescan acquisitions. The Ge concentrations and the local film thickness have been obtained by using a previously described Monte Carlo based “two tilt angles” method. Although the concentrations are in excellent agreement with the known values, the resulting confidence intervals are not as good as expected from the precision in beam positioning and tilt angle position and readout offered by our state-of-the-art microscope. The Gaussian shape of the SiK[alpha] and GeK[alpha] X-ray intensities allows one to use the parametric bootstrap method of statistics, whereby it becomes possible to perform the same quantitative analysis in sample regions of different compositions and thicknesses, but by doing only one measurement at the two angles.

  4. Quantitative thin-film x-ray microanalysis by STEM/HAADF: statistical analysis for precision and accuracy determination.

    PubMed

    Armigliato, Aldo; Balboni, Roberto; Rosa, Rodolfo

    2006-08-01

    Silicon-germanium thin films have been analyzed by EDS microanalysis in a field emission gun scanning transmission electron microscope (FEG-STEM) equipped with a high angular dark-field detector (STEM/HAADF). Several spectra have been acquired in the same homogeneous area of the cross-sectioned sample by drift-corrected linescan acquisitions. The Ge concentrations and the local film thickness have been obtained by using a previously described Monte Carlo based "two tilt angles" method. Although the concentrations are in excellent agreement with the known values, the resulting confidence intervals are not as good as expected from the precision in beam positioning and tilt angle position and readout offered by our state-of-the-art microscope. The Gaussian shape of the SiKalpha and GeKalpha X-ray intensities allows one to use the parametric bootstrap method of statistics, whereby it becomes possible to perform the same quantitative analysis in sample regions of different compositions and thicknesses, but by doing only one measurement at the two angles.

  5. Precision medicine in myasthenia graves: begin from the data precision

    PubMed Central

    Hong, Yu; Xie, Yanchen; Hao, Hong-Jun; Sun, Ren-Cheng

    2016-01-01

    Myasthenia gravis (MG) is a prototypic autoimmune disease with overt clinical and immunological heterogeneity. The data of MG is far from individually precise now, partially due to the rarity and heterogeneity of this disease. In this review, we provide the basic insights of MG data precision, including onset age, presenting symptoms, generalization, thymus status, pathogenic autoantibodies, muscle involvement, severity and response to treatment based on references and our previous studies. Subgroups and quantitative traits of MG are discussed in the sense of data precision. The role of disease registries and scientific bases of precise analysis are also discussed to ensure better collection and analysis of MG data. PMID:27127759

  6. High‐precision iRT prediction in the targeted analysis of data‐independent acquisition and its impact on identification and quantitation

    PubMed Central

    Bruderer, Roland; Bernhardt, Oliver M.; Gandhi, Tejas

    2016-01-01

    Targeted analysis of data‐independent acquisition (DIA) data is a powerful mass spectrometric approach for comprehensive, reproducible and precise proteome quantitation. It requires a spectral library, which contains for all considered peptide precursor ions empirically determined fragment ion intensities and their predicted retention time (RT). RTs, however, are not comparable on an absolute scale, especially if heterogeneous measurements are combined. Here, we present a method for high‐precision prediction of RT, which significantly improves the quality of targeted DIA analysis compared to in silico RT prediction and the state of the art indexed retention time (iRT) normalization approach. We describe a high‐precision normalized RT algorithm, which is implemented in the Spectronaut software. We, furthermore, investigate the influence of nine different experimental factors, such as chromatographic mobile and stationary phase, on iRT precision. In summary, we show that using targeted analysis of DIA data with high‐precision iRT significantly increases sensitivity and data quality. The iRT values are generally transferable across a wide range of experimental conditions. Best results, however, are achieved if library generation and analytical measurements are performed on the same system. PMID:27213465

  7. High-precision iRT prediction in the targeted analysis of data-independent acquisition and its impact on identification and quantitation.

    PubMed

    Bruderer, Roland; Bernhardt, Oliver M; Gandhi, Tejas; Reiter, Lukas

    2016-08-01

    Targeted analysis of data-independent acquisition (DIA) data is a powerful mass spectrometric approach for comprehensive, reproducible and precise proteome quantitation. It requires a spectral library, which contains for all considered peptide precursor ions empirically determined fragment ion intensities and their predicted retention time (RT). RTs, however, are not comparable on an absolute scale, especially if heterogeneous measurements are combined. Here, we present a method for high-precision prediction of RT, which significantly improves the quality of targeted DIA analysis compared to in silico RT prediction and the state of the art indexed retention time (iRT) normalization approach. We describe a high-precision normalized RT algorithm, which is implemented in the Spectronaut software. We, furthermore, investigate the influence of nine different experimental factors, such as chromatographic mobile and stationary phase, on iRT precision. In summary, we show that using targeted analysis of DIA data with high-precision iRT significantly increases sensitivity and data quality. The iRT values are generally transferable across a wide range of experimental conditions. Best results, however, are achieved if library generation and analytical measurements are performed on the same system.

  8. Structural analysis consultation using artificial intelligence

    NASA Technical Reports Server (NTRS)

    Melosh, R. J.; Marcal, P. V.; Berke, L.

    1978-01-01

    The primary goal of consultation is definition of the best strategy to deal with a structural engineering analysis objective. The knowledge base to meet the need is designed to identify the type of numerical analysis, the needed modeling detail, and specific analysis data required. Decisions are constructed on the basis of the data in the knowledge base - material behavior, relations between geometry and structural behavior, measures of the importance of time and temperature changes - and user supplied specifics characteristics of the spectrum of analysis types, the relation between accuracy and model detail on the structure, its mechanical loadings, and its temperature states. Existing software demonstrated the feasibility of the approach, encompassing the 36 analysis classes spanning nonlinear, temperature affected, incremental analyses which track the behavior of structural systems.

  9. Analysis of pattern precision shows that Drosophila segmentation develops substantial independence from gradients of maternal gene products.

    PubMed

    Holloway, David M; Harrison, Lionel G; Kosman, David; Vanario-Alonso, Carlos E; Spirov, Alexander V

    2006-11-01

    We analyze the relation between maternal gradients and segmentation in Drosophila, by quantifying spatial precision in protein patterns. Segmentation is first seen in the striped expression patterns of the pair-rule genes, such as even-skipped (eve). We compare positional precision between Eve and the maternal gradients of Bicoid (Bcd) and Caudal (Cad) proteins, showing that Eve position could be initially specified by the maternal protein concentrations but that these do not have the precision to specify the mature striped pattern of Eve. By using spatial trends, we avoid possible complications in measuring single boundary precision (e.g., gap gene patterns) and can follow how precision changes in time. During nuclear cleavage cycles 13 and 14, we find that Eve becomes increasingly correlated with egg length, whereas Bcd does not. This finding suggests that the change in precision is part of a separation of segmentation from an absolute spatial measure, established by the maternal gradients, to one precise in relative (percent egg length) units.

  10. Remote sensing for precision agriculture: Within-field spatial variability analysis and mapping with aerial digital multispectral images

    NASA Astrophysics Data System (ADS)

    Gopalapillai, Sreekala

    2000-10-01

    Advances in remote sensing technology and biological sensors provided the motivation for this study on the applications of aerial multispectral remote sensing in precision agriculture. The feasibility of using high-resolution multispectral remote sensing for precision farming applications such as soil type delineation, identification of crop nitrogen levels, and modeling and mapping of weed density distribution and yield potential within a crop field was explored in this study. Some of the issues such as image calibration for variable lighting conditions and soil background influence were also addressed. Intensity normalization and band ratio methods were found to be adequate image calibration methods to compensate for variable illumination and soil background influence. Several within-field variability factors such as growth stage, field conditions, nutrient availability, crop cultivar, and plant population were found to be dominant in different periods. Unsupervised clustering of color infrared (CIR) image of a field soil was able to identify soil mapping units with an average accuracy of 76%. Spectral reflectance from a crop field was highly correlated to the chlorophyll reading. A regression model developed to predict nitrogen stress in corn identified nitrogen-stressed areas from nitrogen-sufficient areas with a high accuracy (R2 = 0.93). Weed density was highly correlated to the spectral reflectance from a field. One month after planting was found to be a good time to map spatial weed density. The optimum range of resolution for weed mapping was 4 m to 4.5 m for the remote sensing system and the experimental field used in this study. Analysis of spatial yield with respect to spectral reflectance showed that the visible and NIR reflectance were negatively correlated to yield and crop population in heavily weed-infested areas. The yield potential was highly correlated to image indices, especially to normalized brightness. The ANN model developed for one of the

  11. A high-precision chemical abundance analysis of the HAT-P-1 stellar binary: constraints on planet formation

    NASA Astrophysics Data System (ADS)

    Liu, F.; Asplund, M.; Ramírez, I.; Yong, D.; Meléndez, J.

    2014-07-01

    We present a high-precision, differential elemental abundance analysis of the HAT-P-1 stellar binary based on high-resolution, high signal-to-noise ratio Keck/HIRES (High Resolution Echelle Spectrometer) spectra. The secondary star in this double system is known to host a transiting giant planet while no planets have yet been detected around the primary star. The derived metallicities ([Fe/H]) of the primary and secondary stars are identical within the errors: 0.146 ± 0.014 dex (σ = 0.033 dex) and 0.155 ± 0.007 dex (σ = 0.023 dex), respectively. Extremely precise differential abundance ratios of 23 elements have been measured (mean error of σ([X/Fe]) = 0.013 dex) and are found to be indistinguishable between the two stars: Δ[X/Fe] (secondary - primary) = +0.001 ± 0.006 dex (σ = 0.008 dex). The striking similarity in the chemical composition of the two stellar components in HAT-P-1 is contrary to the possible 0.04 dex level difference seen in 16 Cyg A+B, which also hosts a giant planet, at least three times more massive than the one around HAT-P-1 secondary star. We conclude that the presence of giant planets does not necessarily imply differences in the chemical compositions of the host stars. The elemental abundances of each star in HAT-P-1 relative to the Sun show an identical, positive correlation with the condensation temperature of the elements; their abundance patterns are thus very similar to those observed in the majority of solar twins. In view of the Meléndez et al. interpretation of the peculiar solar abundance pattern, we conclude that HAT-P-1 experienced less efficient formation of terrestrial planets than the Sun. This is in line with the expectation that the presence of close-in giant planets preventing the formation or survival of terrestrial planets.

  12. Existing Resources, Standards, and Procedures for Precise Monitoring and Analysis of Structural Deformations. Volume 1

    DTIC Science & Technology

    1992-09-01

    commonplace, particularly in the monitoring of dams and hydro-electric power generating stations. Italy’s ENEL (Ente Nazionale per 1’ Energia Elettrica...State Commissions to enfo