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Sample records for precise structure analysis

  1. 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.

  2. Probabilistic constraints on structural lineament best fit plane precision obtained through numerical analysis

    NASA Astrophysics Data System (ADS)

    Seers, Thomas D.; Hodgetts, David

    2016-01-01

    Understanding the orientation distribution of structural discontinuities using the limited information afforded by their trace in outcrop has considerable application, with such analysis often providing the basis for geological modelling. However, eigen analysis of 3D structural lineaments mapped at decimetre to regional scales indicates that discontinuity best fit plane estimates from such datasets tend to be unreliable. Here, the relationship between digitised lineament vertex geometry (coplanarity/collinearity) and the reliability of their estimated best fitting plane is investigated using Monte Carlo experiments. Lineaments are modelled as the intersection curve between two orthonormally oriented fractional Brownian surfaces representing the outcrop and discontinuity plane. Commensurate to increasing lineament vertex collinearity (K), systematic decay in estimated pole vector precision is observed from these experiments. Pole vector distributions are circumferentially constrained around the axis of rotation set by the end nodes of the synthetic lineaments, reducing the rotational degrees of freedom of the vertex set from three to one. Vectors on the unit circle formed perpendicular to this arbitrary axis of rotation conform to von Mises (circular normal) distributions tending towards uniform at extreme values of K. This latter observation suggests that whilst intrinsically unreliable, confidence limits can be placed upon orientation estimates from 3D structural lineaments digitised from remotely sensed data. A probabilistic framework is introduced which draws upon the statistical constraints obtained from our experiments to provide robust best fit plane estimates from digitised 3D structural lineaments.

  3. 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.

  4. Probabilistic Constraints on Structural Lineament Best Fit Plane Precision Obtained through Numerical Analysis

    NASA Astrophysics Data System (ADS)

    Seers, Thomas; Hodgetts, David

    2015-04-01

    Recent advances in geological trace extraction procedures now enable three dimensional representations of structural lineaments to be delineated from digital elevation models (DEMs), orthophotos and mesh based surface reconstructions. The principle advantage of obtaining higher dimensional representations of lineaments from remotely sensed data is that they allow best fit plane estimates to be made for their corresponding discontinuities which cannot be obtained from conventional bi-dimensional datasets. These orientation estimates yield deterministic constraints upon structural architecture and enable spatially dependent discontinuity network properties, such as volumetric intensity and connectivity, known to govern key rock mass physical properties (i.e. strength, elastic modulus and permeability) to be assessed. However, the eigen characteristics of 3D structural lineaments mapped at decimetre to regional scales indicates that discontinuity plane estimates from such datasets tend to be unreliable. Here, we investigate the relationship between digitised lineament vertex geometry (coplanarity/collinearity) and the reliability of their estimated best fitting plane using Monte Carlo experiments. Lineaments are modelled as the intersection curve between two orthonormally oriented fractional Brownian surfaces representing the outcrop and discontinuity plane. Commensurate to increasing lineament vertex collinearity (K), systematic decay in estimated pole vector precision is observed from our experiments. Pole vector distributions are circumferentially constrained around the axis of rotation set by the end nodes of the synthetic lineaments, effectively reducing the rotational degrees of freedom of the vertex set from three to one. Vectors on the unit circle formed perpendicular to this arbitrary axis of rotation conform to von Mises (circular normal) distributions, only transforming to uniform at extreme values of K. This latter observation suggests that whilst

  5. Assembling Precise Truss Structures With Minimal Stresses

    NASA Technical Reports Server (NTRS)

    Sword, Lee F.

    1996-01-01

    Improved method of assembling precise truss structures involves use of simple devices. Tapered pins that fit in tapered holes indicate deviations from prescribed lengths. Method both helps to ensure precision of finished structures and minimizes residual stresses within structures.

  6. 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…

  7. 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.

  8. Study on control structure analysis and optimization of high-precision measurement platform for optical aspheric surface

    NASA Astrophysics Data System (ADS)

    Ke, Xiaolong; Guo, Yinbiao; Wang, Zhengzhong; Liu, Jianchun

    2009-05-01

    Taking high generality and efficiency into account, this paper presents a measurement and control means based on high-precision measurement platform including high-precision linear motors, contact and non-contact measurement sensor of 0.1um resolution and a new developed measuring software. This platform aims to achieve high-precision measurement for all kinds of optical aspheric workpieces for detection accuracy of 2um/200*200mm. In this paper, a measurement platform which consists of granite gantry framework, 3 axes linear motors, circle grating rotary encoder, grating linear scales, 4 axes motion control card, linear motion ball guide, contacting and non-contacting measurement sensor and so on, is designed and implemented. Through finite element stress analysis, it can find that the framework well fulfills the accuracy demand. And the performance comparison between linear motors and piezoelectric ceramics motors is then discussed. Further, it also compares the coordinated motion of "circle grating rotary encoder+2 axes linear motors" with the coordinated motion of "3 axes linear motors" to find out the difference in measurement accuracy by experiment data. Here, a better scheme for kinematic locus planning is proposed for making sure all axes have better dynamic characteristics. Aiming at various characteristics of optical workpieces, the different measurement paths are also provided. Finally, the experiments for this purpose are done to validate the measurement platform accuracy.

  9. Active-member control of precision structures

    NASA Technical Reports Server (NTRS)

    Fanson, J. L.; Blackwood, G. H.; Chu, C. C.

    1989-01-01

    This paper presents the results of closed loop experiments that use piezoelectric active-members to control the flexible motion of a precision truss structure. These experiments are directed toward the development of high performance structural systems as part of the Control/Structure Interaction program at JPL. Order of magnitude reductions in dynamic response are achieved with relatively simple control techniques. The practical implementation of high stiffness, high bandwidth active-members in a precision structure highlights specific issues of importance relating to the modelling and implementation of active-member control.

  10. 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.

  11. Structural Characterization of Layered Morphologies in Precise Copolymers

    NASA Astrophysics Data System (ADS)

    Trigg, Edward; Gaines, Taylor; Wagener, Kenneth; Winey, Karen

    2015-03-01

    Layered morphologies have been observed in precise polyethylene-based copolymers that contain acid, charged, or polar functional groups precisely spaced along a linear alkane chain. Sufficiently long alkane segments form structures resembling orthorhombic polyethylene crystals, while the functional groups form 2-D layers that disrupt the alkane crystal structure to varying degrees. Here, layered morphologies in precise copolymers containing acrylic acid, phosphonic acid, imidazolium bromide, and sulfone groups are studied via X-ray scattering. Specifically, the composition profiles of the layered structures are obtained by Fourier synthesis, and the coherence length is investigated using peak width analysis. This analysis indicates that the layers of functional groups are frequently bordered by two crystallites, which suggests different dynamics relative to layers bordered by one crystalline and one amorphous microdomain. Detailed understanding of the structure of the layered morphologies will allow for a systematic investigation of proton and ion conductivity mechanisms, which are expected to occur through the high-dielectric layers.

  12. Ground test validation for precision structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Garba, John A.; Fanson, James L.

    1991-01-01

    Future proposed NASA missions will require large precision truss type structures that are deployed or assembled in space. To date, space structures that are important to missions success have been ground tested to validate their performance. Evaluation of the performance requirements of future systems has shown that using current and projected design and test approaches, the structure cannot be adequately validated by ground test. A problem exists since it is believed that unless important structure systems can be validated by ground tests, they will never be adopted for future missions. New design or ground test approaches are necessary to enable future missions. The inability of current approaches to validate future structural systems is discussed.

  13. 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.

  14. 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.

  15. 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.

  16. Recent results on structural control of an active precision structure

    NASA Technical Reports Server (NTRS)

    Chu, C. C.; Fanson, J. L.; Smith, R. S.

    1991-01-01

    This paper describes recent results in structural control of an active precision truss structure at JPL. The goal is to develop practical control methodology and to apply to active truss structures intended for high precision space-based optics applications. The active structure considered incorporates piezoelectric active members which apply control forces internal to the structure and thereby improve the structure's dimensional stability. Two approaches to structural control system design were investigated. The first approach uses only noncollocated measurements of acceleration at the location of a simulated optical component to achieve structural stabilization. The second approach is essentially the same as the first one except that a viscous damper was used in place of a truss member on the structure to improve the dampings of selected flexible modes. The corresponding experimental closed-loop results are presented in this paper.

  17. 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…

  18. Adaptive structures to meet future requirements for large precision structures

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    The role of adaptive structures in meeting the structural requirements for future NASA missions is described. Many of NASA's future missions require large precision truss type structures where prespecified locations on the structure must maintain micron level accuracies with respect to each other when subjected to manufacturing errors and static, thermal, and dynamic inputs. In many cases the incorporation of the adaptive structures concepts into the structural design to adjust the on-orbit structure will be the only feasible means to attain the desired accuracies. In order for the structures to be able to change structural characteristics on orbit they must be uncoupled and independent of the control system used to impart the required rigid body motion to the spacecraft.

  19. 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

  20. 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.

  1. 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.

  2. Precision Measurement of Large Scale Structure

    NASA Technical Reports Server (NTRS)

    Hamilton, A. J. S.

    2001-01-01

    The purpose of this grant was to develop and to start to apply new precision methods for measuring the power spectrum and redshift distortions from the anticipated new generation of large redshift surveys. A highlight of work completed during the award period was the application of the new methods developed by the PI to measure the real space power spectrum and redshift distortions of the IRAS PSCz survey, published in January 2000. New features of the measurement include: (1) measurement of power over an unprecedentedly broad range of scales, 4.5 decades in wavenumber, from 0.01 to 300 h/Mpc; (2) at linear scales, not one but three power spectra are measured, the galaxy-galaxy, galaxy-velocity, and velocity-velocity power spectra; (3) at linear scales each of the three power spectra is decorrelated within itself, and disentangled from the other two power spectra (the situation is analogous to disentangling scalar and tensor modes in the Cosmic Microwave Background); and (4) at nonlinear scales the measurement extracts not only the real space power spectrum, but also the full line-of-sight pairwise velocity distribution in redshift space.

  3. 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

  4. 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. PMID:22163499

  5. 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.

  6. Increased localization precision by interference fringe analysis.

    PubMed

    Ebeling, Carl G; Meiri, Amihai; Martineau, Jason; Zalevsky, Zeev; Gerton, Jordan M; Menon, Rajesh

    2015-06-21

    We report a novel optical single-emitter-localization methodology that uses the phase induced by path length differences in a Mach-Zehnder interferometer to improve localization precision. Using information theory, we demonstrate that the localization capability of a modified Fourier domain signal generated by photon interference enables a more precise localization compared to a standard Gaussian intensity distribution of the corresponding point-spread function. The calculations were verified by numerical simulations and an exemplary experiment, where the centers of metal nanoparticles were localized to a precision of 3 nm. PMID:25999093

  7. 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.

  8. 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.

  9. Precise Analysis of Polymer Rotational Dynamics.

    PubMed

    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

  10. 3D precision surface measurement by dynamic structured light

    NASA Astrophysics Data System (ADS)

    Franke, Ernest A.; Magee, Michael J.; Mitchell, Joseph N.; Rigney, Michael P.

    2004-02-01

    This paper describes a 3-D imaging technique developed as an internal research project at Southwest Research Institute. The technique is based on an extension of structured light methods in which a projected pattern of parallel lines is rotated over the surface to be measured. A sequence of images is captured and the surface elevation at any location can then be determined from measurements of the temporal pattern, at any point, without considering any other points on the surface. The paper describes techniques for system calibration and surface measurement based on the method of projected quadric shells. Algorithms were developed for image and signal analysis and computer programs were written to calibrate the system and to calculate 3-D coordinates of points on a measured surface. A prototype of the Dynamic Structured Light (DSL) 3-D imaging system was assembled and typical parts were measured. The design procedure was verified and used to implement several different configurations with different measurement volumes and measurement accuracy. A small-parts measurement accuracy of 32 micrometers (.0012") RMS was verified by measuring the surface of a precision-machined plane. Large aircraft control surfaces were measured with a prototype setup that provided .02" depth resolution over a 4" by 8" field of view. Measurement times are typically less than three minutes for 300,000 points. A patent application has been filed.

  11. Precise correlation between structural and electrophysiological disturbances in MADSAM neuropathy.

    PubMed

    Simon, Neil G; Kiernan, Matthew C

    2015-11-01

    Multifocal acquired demyelinating sensory and motor neuropathy is characterised by multifocal clinical deficits. Imaging studies have identified multifocal enlargements of nerve trunks, but a precise correlation between structural abnormalities and electrophysiological dysfunction has not been elucidated. Two patients diagnosed with multifocal acquired demyelinating sensory and motor neuropathy were evaluated with nerve conduction studies, including short segment nerve conduction studies to precisely localise motor conduction block, and ultrasound studies of corresponding nerve trunks. Motor conduction block was identified in each patient (upper limb nerves in two patients), superimposed on additional demyelinating neurophysiological features. Upper limb ultrasound studies demonstrated focal nerve enlargement that precisely correlated with neurophysiological conduction block. The results of this study suggest that factors contributing to focal structural abnormalities in multifocal acquired demyelinating sensory and motor neuropathy are also those that produce conduction block. PMID:26314279

  12. Composite material technology requirements for large precision space structures

    NASA Technical Reports Server (NTRS)

    Mcelroy, P. M.; Helms, R. G.

    1984-01-01

    The development of dimensionally stable, precision composite structures has been recognized as a high risk technology driver in NASA's continuing large space structures research. Attempts are being made to understand the influences controlling thermal performance in such composites, and specifically in composite sandwich panels. The necessary tools for such composite panels' deployment, the experimental verification of analytical predictions, and the demonstration of technology in small scale hardware, are presently addressed.

  13. Precision Penning Trap Mass Measurements for Nuclear Structure at Triumf

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, A. A.; Dilling, J.; Andreoiu, C.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Delheij, P.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Gwinner, G.; Lennarz, A.; Mané, E.; Pearson, M. R.; Schultz, B. E.; Simon, M. C.; Simon, V. V.

    2013-03-01

    Precision determinations of ground state or even isomeric state masses reveal fingerprints of nuclear structure. In particular at the limits at existence for very neutron-rich or deficient isotopes, this allows one to find detailed information about nuclear structure from separation energies or binding energies. This is important to test theoretical predictions or to refine model approaches, for example for new "magic numbers," as predicted around N = 34, where strong indications exist that the inclusion of NNN forces in theoretical calculations for Ca isotopes leads to significantly better predictions for ground state binding energies. Similarly, halo nuclei present an excellent application for ab-initio theory, where ground state properties, like masses and radii, present prime parameters for testing our understanding of nuclear structure. Precision mass determinations at TRIUMF are carried out with the TITAN (TRIUMF's Ion Trap for Atomic and Nuclear science) system. It is an ion trap setup coupled to the on-line facility ISAC. TITAN has measured masses of isotopes as short-lived as 9 ms (almost an order of magnitude shorter-lived than any other Penning trap system) and the only one with charge breeding capabilities, a feature that allows us to boost the precision by almost 2 orders of magnitude. We recently were able to make use of this feature by measuring short-lived Rb-isotopes, up to 74Rb, and reaching the 12+ charge state, which together with other improvements lead to an increase in precision by a factor 36.

  14. Ground test validation of large precision structure through adaptive structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.

    1992-01-01

    Without novel ground validation test (GVT) approaches for such space structures as those contemplated for an orbiting optical interferometer, this and other NASA missions will be stillborn. One such approach may involve the integration of adaptive structures concepts into initial structural designs, in order to accommodate GVT, as well as to allow for redundancy and enhance mission reliability. Adaptive structures are noted to intrinsically relax GVT requirements.

  15. 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.

  16. 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…

  17. Precision and Accuracy Parameters in Structured Light 3-D Scanning

    NASA Astrophysics Data System (ADS)

    Eiríksson, E. R.; Wilm, J.; Pedersen, D. B.; Aanæs, H.

    2016-04-01

    Structured light systems are popular in part because they can be constructed from off-the-shelf low cost components. In this paper we quantitatively show how common design parameters affect precision and accuracy in such systems, supplying a much needed guide for practitioners. Our quantitative measure is the established VDI/VDE 2634 (Part 2) guideline using precision made calibration artifacts. Experiments are performed on our own structured light setup, consisting of two cameras and a projector. We place our focus on the influence of calibration design parameters, the calibration procedure and encoding strategy and present our findings. Finally, we compare our setup to a state of the art metrology grade commercial scanner. Our results show that comparable, and in some cases better, results can be obtained using the parameter settings determined in this study.

  18. 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.

  19. 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.

  20. 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.

  1. 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).

  2. 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.

  3. 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.

  4. 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.

  5. 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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  7. Analytical precision of one-sixth order semiquantitative spectrographic analysis

    USGS Publications Warehouse

    Motooka, J.M.; Grimes, D.J.

    1976-01-01

    Over 2,700 separate analyses were made on 22 different geologic samples selected to cover wide concentration ranges for the 30 elements studied. The precision for low, medium, and high concentrations of each element determined is represented by superimposed frequency diagrams and displays the frequency of reported values occurring within one-sixth order reporting intervals about the mean.Results are derived from mixed analyst and instrument conditions with no controls enforced other than randomization of samples. The precision of the six-step (one-sixth order) semiquantitative spectrographic analysis utilized by the Denver-based mobile laboratories exceeds that which is necessary for exploration geochemistry. Disallowing results obtained near the detection levels, the repeatability of the method, in general, is shown to be within on adjoining reporting interval on each side of the mean, 83 percent of the time, and within two adjoining reporting intervals on each side of the mean 96 percent of the time.

  8. 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

  9. 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.

  10. High-precision position-specific isotope analysis

    PubMed Central

    Corso, Thomas N.; Brenna, J. Thomas

    1997-01-01

    Intramolecular carbon isotope distributions reflect details of the origin of organic compounds and may record the status of complex systems, such as environmental or physiological states. A strategy is reported here for high-precision determination of 13C/12C ratios at specific positions in organic compounds separated from complex mixtures. Free radical fragmentation of methyl palmitate, a test compound, is induced by an open tube furnace. Two series of peaks corresponding to bond breaking from each end of the molecule are analyzed by isotope ratio mass spectrometry and yield precisions of SD(δ-13C) < 0.4‰. Isotope labeling in the carboxyl, terminal, and methyl positions demonstrates the absence of rearrangement during activation and fragmentation. Negligible isotopic fractionation was observed as degree of fragmentation was adjusted by changing pyrolysis temperature. [1-13C]methyl palmitate with overall δ-13C = 4.06‰, yielded values of +457‰ for the carboxyl position, in agreement with expectations from the dilution, and an average of −27.95‰ for the rest of the molecule, corresponding to −27.46‰ for the olefin series. These data demonstrate the feasibility of automated high-precision position-specific analysis of carbon for molecules contained in complex mixtures. PMID:11038597

  11. Disentangling perturbative and power corrections in precision tau decay analysis

    SciTech Connect

    Gorbunov, D.S.; Pivovarov, A.A.

    2005-01-01

    Hadronic tau decay precision data are analyzed with account of both perturbative and power corrections of high orders within QCD. It is found that contributions of high order power corrections are essential for extracting a numerical value for the strange quark mass from the data on Cabibbo suppressed tau decays. We show that with inclusion of new five-loop perturbative corrections in the analysis the convergence of perturbation theory remains acceptable only for few low order moments. We obtain m{sub s}(M{sub {tau}})=130{+-}27 MeV in agreement with previous estimates.

  12. 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.

  13. 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.

  14. 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

  15. Adaptive structures for precision controlled large space systems

    NASA Technical Reports Server (NTRS)

    Garba, John A.; Wada, Ben K.; Fanson, James L.

    1991-01-01

    The stringent accuracy and ground test validation requirements of some of the future space missions will require new approaches in structural design. Adaptive structures, structural systems that can vary their geometric congiguration as well as their physical properties, are primary candidates for meeting the functional requirements for such missions. Research performed in the development of such adaptive structural systems is described.

  16. High-precision analysis of SF6 at ambient level

    NASA Astrophysics Data System (ADS)

    Lim, J. S.; Moon, D. M.; Kim, J. S.; Yun, W.-T.; Lee, J.

    2013-09-01

    This work reports on the development of a technique for the precise analysis of ambient SF6. This technique, which involves a gas chromatograph/electron capture detector (GC-ECD) coupled with an Activated Alumina-F1 (AA-F1) column, performed well in the measurements, particularly in terms of accuracy, which complies with the World Meteorological Organization (WMO)-recommended compatibility of 0.02 ppt. Compared to the Porapak Q technique, we observed a sharper peak shape for the SF6 stream, which substantiates the improvement in the analytical precision. The traceability to the WMO scale was tested by calibrating the GC-ECD/AA-F1 analyser using five SF6 standards provided by the WMO/Global Atmosphere Watch (GAW) Central Calibration Laboratory (CCL) for SF6 (NOAA, United States of America). After calibration by various methods, the GC-ECD/AA-F1 accurately estimated the mole fraction of SF6 in the working standard prepared by the World Calibration Centre for SF6 operated by the Korea Meteorological Administration (KMA)/Korea Research Institute of Standards and Science (KRISS). Among the calibration methods, the two-point calibration method emerged to be the most economical procedure in terms of the data quality and measurement time. It was found that the KRISS scale of SF6/N2 was biased by 0.13 ppt when compared to the WMO scale of SF6/air; this bias is probably due to a different matrix.

  17. 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. PMID:25075321

  18. Optimization design about gimbal structure of high-precision autonomous celestial navigation tracking mirror system

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Yang, Xiao-xu; Han, Jun-feng; Wei, Yu; Zhang, Jing; Xie, Mei-lin; Yue, Peng

    2016-01-01

    High precision tracking platform of celestial navigation with control mirror servo structure form, to solve the disadvantages of big volume and rotational inertia, slow response speed, and so on. It improved the stability and tracking accuracy of platform. Due to optical sensor and mirror are installed on the middle-gimbal, stiffness and resonant frequency requirement for high. Based on the application of finite element modality analysis theory, doing Research on dynamic characteristics of the middle-gimbal, and ANSYS was used for the finite element dynamic emulator analysis. According to the result of the computer to find out the weak links of the structure, and Put forward improvement suggestions and reanalysis. The lowest resonant frequency of optimization middle-gimbal avoid the bandwidth of the platform servo mechanism, and much higher than the disturbance frequency of carrier aircraft, and reduces mechanical resonance of the framework. Reaching provides a theoretical basis for the whole machine structure optimization design of high-precision of autonomous Celestial navigation tracking mirror system.

  19. Development of an active truss element for control of precision structures

    NASA Technical Reports Server (NTRS)

    Anderson, Eric H.; Moore, Donald M.; Fanson, James L.; Ealey, Mark A.

    1990-01-01

    An active structural element for use in precision control of large space structures is described. The active member is intended to replace a passive strut in a truss-like structure. It incorporates an eddy current displacement sensor and an actuator that is either piezoelectric (PZT) or electrostrictive (PMN). The design of the device is summarized. Performance of separate PZT and PMN actuators is compared for several properties relevant to submicrometer control of precision structures.

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

    NASA Astrophysics Data System (ADS)

    Galarza, Jhon Yana; 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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

  2. 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.

  3. 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.

  4. Precise and feasible measurements of lateral calcaneal lengthening osteotomies by radiostereometric analysis in cadaver feet

    PubMed Central

    Martinkevich, P.; Rahbek, O.; Møller-Madsen, B.; Søballe, K.; Stilling, M.

    2015-01-01

    Objectives Lengthening osteotomies of the calcaneus in children are in general grafted with bone from the iliac crest. Artificial bone grafts have been introduced, however, their structural and clinical durability has not been documented. Radiostereometric analysis (RSA) is a very accurate and precise method for measurements of rigid body movements including the evaluation of joint implant and fracture stability, however, RSA has not previously been used in clinical studies of calcaneal osteotomies. We assessed the precision of RSA as a measurement tool in a lateral calcaneal lengthening osteotomy (LCLO). Methods LCLO was performed in six fixed adult cadaver feet. Tantalum markers were inserted on each side of the osteotomy and in the cuboideum. Lengthening was done with a plexiglas wedge. A total of 24 radiological double examinations were obtained. Two feet were excluded due to loose and poorly dispersed markers. Precision was assessed as systematic bias and 95% repeatability limits. Results Systematic bias was generally below 0.10 mm for translations. Precision of migration measurements was below 0.2 mm for translations in the osteotomy. Conclusion RSA is a precise tool for the evaluation of stability in LCLO. Cite this article: Bone Joint Res 2015;4:78–83. PMID:25957380

  5. Sequencing Structural Variants in Cancer for Precision Therapeutics.

    PubMed

    Macintyre, Geoff; Ylstra, Bauke; Brenton, James D

    2016-09-01

    The identification of mutations that guide therapy selection for patients with cancer is now routine in many clinical centres. The majority of assays used for solid tumour profiling use DNA sequencing to interrogate somatic point mutations because they are relatively easy to identify and interpret. Many cancers, however, including high-grade serous ovarian, oesophageal, and small-cell lung cancer, are driven by somatic structural variants that are not measured by these assays. Therefore, there is currently an unmet need for clinical assays that can cheaply and rapidly profile structural variants in solid tumours. In this review we survey the landscape of 'actionable' structural variants in cancer and identify promising detection strategies based on massively-parallel sequencing. PMID:27478068

  6. Diffraction signature analysis methods for improving scatterometry precision

    NASA Astrophysics Data System (ADS)

    Littau, Mike; Forman, Darren; Bruce, Josh; Raymond, Christopher J.; Hummel, Steven G.

    2006-03-01

    Scatterometry is a fast, non-destructive critical dimension (CD) optical metrology technique based on the analysis of light scattered from a periodic array of features. With technological advances in manufacturing, semiconductor devices are made in ever shrinking geometries. In recent years, the ability of scatterometry metrology tools to measure these devices at a gage-capable level for parameters such as CD, thickness or profile has become more challenging. The focus of this research is to analyze the acquired diffraction signature and determine an optimum diffraction signature "scan path." An optimized scan path can result in higher precision, reduced development time, smaller pre-generated library databases and faster real-time optimization speeds. In this work, we will first review several methods for scan path selection and optimization. Our results indicate that the method choice can influence the scan path selection, and that some of the methods are complementary to one another. For example, one method, which we term orthogonal sensitivity, uses intelligent algorithms to select optimal scan path points based on enhancing single parameter sensitivity. While the method works well, it neglects parameter correlation effects. Thus, we will also review a method where correlation effects are considered. Finally, we will calculate and summarize the effectiveness of optimal scan path selection techniques using challenging lithography applications.

  7. Precision stabilization system for MIS-structure rf capacitance

    SciTech Connect

    Antonenko, V.I.; Zhdan, A.G.

    1987-02-01

    A relatively simple resonant small-signal system is described for stabilization of the rf capacitance of MIS structures in the frequency range of 1-30 MHz that is based on a VM560 Q-meter. The relative sensitivity to capacitance variation ..delta..C/C is 2 x 10/sup -6/ at a level of C approx. 500 pF, the absolute sensitivity ..delta..C approx. 1 fF, and the response time is approx. 0.1 sec. The system is designed for relaxation spectroscopy of boundary states in MIS structures in the constant-capacitance mode by methods of unsteady capacitance and thermostimulated discharge of an MIS capacitor.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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. PMID:26062738

  14. 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.

  15. 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.

  16. 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

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

    PubMed

    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

  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. Seismicity analysis in Indonesia region from high precision hypocenter location

    NASA Astrophysics Data System (ADS)

    Nugraha, Andri; Shiddiqi, Hasbi; Widiyantoro, Sri; Ramdhan, Mohamad; Wandono, Wandono

    2015-04-01

    As a complex tectonic region, Indonesia has a high seismicity rate which is related to subduction and collision as well as strike-slip fault. High-precision earthquake locations with adequate relocation method and proper velocity model are necessary for seismicity analysis. We used nearly 25,000 earthquakes that were relocated using double-difference method. In our relocation process, we employed teleseismic, regional, and local P-wave arrival times. Furthermore, we employed regional-global nested velocity models that take into account the subduction slab in the study region by using a 3D model for area inside and a 1D model for area outside Indonesia. Relocation results show shifted hypocenters that are generally perpendicular to the trench. Beneath western Sunda arc, the Wadati-Benioff Zone (WBZ) extents to a depth of about 300 km and depicts a gently dipping slab. The WBZ beneath eastern Sunda arc extends deeper to about 500 km and depicts a steep slab geometry. In the Sunda-Banda transition zone, we found anomalously low seismicity beneath the oceanic-continental transition region. The WBZ of the severely curved Banda arc extends to a depth of about 600 km and depicts a two-slab model. In the Molucca collision zone, seismicity clearly depicts two opposing slabs of the Molucca sea plate, i.e. to the east and to the west. Around Sulawesi region, most earthquakes are related to the north Sulawesi trench and depict subducted slab beneath the northern part of the island. In Sumatra region, we identified a seismic gap in the WBZ between 70 km and 150 km. Seismicity gaps are also detected beneath particular regions, e.g. Mentawai region, and several parts along the subducted slab. Similar to the Sumatra region, beneath eastern Sunda arc, seismic gap in WBZ is also detected but deeper, i.e. at depths of 150 km to 250 km. Furthermore, we used global centroid moment tensor catalog data available for earthquakes with magnitude 5.0 or greater. In general, focal mechanism

  20. ON-FARM ANALYSIS OF PRECISION FARMING PRACTICES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision farming technologies are becoming increasingly popular. However, few studies have addressed the whole farm and per acre expense of these technologies. A 33-acre farm example is used to establish baseline cost estimates of these technologies. Findings suggest that per acre expense is relati...

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Structural scheme optimization design for the stationary platen of a precision plastic injection molding machine

    NASA Astrophysics Data System (ADS)

    Ren, Bin; Zhang, Shuyou; Tan, Jianrong

    2014-07-01

    The current development of precision plastic injection molding machines mainly focuses on how to save material and improve precision, but the two aims contradict each other. For a clamp unit, clamping precision improving depends on the design quality of the stationary platen. Compared with the parametric design of stationary platen, structural scheme design could obtain the optimization model with double objectives and multi-constraints. In this paper, a SE-160 precision plastic injection molding machine with 1600 kN clamping force is selected as the subject in the case study. During the motion of mold closing and opening, the stationary platen of SE-160 is subjected to a cyclic loading, which would cause the fatigue rupture of the tie bars in periodically long term operations. In order to reduce the deflection of the stationary platen, the FEA method is introduced to optimize the structure of the stationary platen. Firstly, an optimal topology model is established by variable density method. Then, structural topology optimizations of the stationary platen are done with the removable material from 50%, 60% to 70%. Secondly, the other two recommended optimization schemes are given and compared with the original structure. The result of performances comparison shows that the scheme II of the platen is the best one. By choosing the best alternative, the volume and the local maximal stress of the platen could be decreased, corresponding to cost-saving material and better mechanical properties. This paper proposes a structural optimization design scheme, which can save the material as well as improve the clamping precision of the precision plastic injection molding machine.

  7. 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.

  8. Analysis of HY2A precise orbit determination using DORIS

    NASA Astrophysics Data System (ADS)

    Gao, Fan; Peng, Bibo; Zhang, Yu; Evariste, Ngatchou Heutchi; Liu, Jihua; Wang, Xiaohui; Zhong, Min; Lin, Mingsen; Wang, Nazi; Chen, Runjing; Xu, Houze

    2015-03-01

    HY2A is the first Chinese marine dynamic environment satellite. The payloads include a radar altimeter to measure the sea surface height in combination with a high precision orbit to be determined from tracking data. Onboard satellite tracking includes GPS, SLR, and the DORIS DGXX receiver which delivers phase and pseudo-range measurements. CNES releases raw phase and pseudo-range measurements with RINEX DORIS 3.0 format and pre-processed Doppler range-rate with DORIS 2.2 data format. However, the VMSI software package developed by Van Martin Systems, Inc which is used to estimate HY2A DORIS orbits can only process Doppler range-rate but not the DORIS phase data which are available with much shorter latency. We have proposed a method of constructing the phase increment data, which are similar to range-rate data, from RINEX DORIS 3.0 phase data. We compute the HY2A orbits from June, 2013 to August, 2013 using the POD strategy described in this paper based on DORIS 2.2 range-rate data and our reconstructed phase increment data. The estimated orbits are evaluated by comparing with the CNES precise orbits and SLR residuals. Our DORIS-only orbits agree with the precise GPS + SLR + DORIS CNES orbits radially at 1-cm and about 3-cm in the other two directions. SLR test with the 50° cutoff elevation shows that the CNES orbit can achieve about 1.1-cm accuracy in radial direction and our DORIS-only POD solutions are slightly worse. In addition, other HY2A DORIS POD concerns are discussed in this paper. Firstly, we discuss the frequency offset values provided with the RINEX data and find that orbit accuracy for the case when the frequency offset is applied is worse than when it is not applied. Secondly, HY2A DORIS antenna z-offsets are estimated using two kinds of measurements from June, 2013 to August, 2013. The results show that the measurement errors contribute a total of about 2-cm difference of estimated z-offset. Finally, we estimate HY2A orbits selecting 3 days with

  9. 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.

  10. Crystal Structures of Precise Functional Copolymers: Atomistic Molecular Dynamics Simulations and Comparisons with Experiments

    NASA Astrophysics Data System (ADS)

    Trigg, Edward B.; Stevens, Mark J.; Winey, Karen I.

    Layered crystal structures have been observed in linear poly(ethylene-co-acrylic acid) in which the carboxylic acid groups are placed precisely every 21 carbon atoms along the backbone. The alkane segments form structures resembling orthorhombic polyethylene crystals, while the acid groups form continuous domains that may act as pathways for ion conduction. Further details of the crystal structure have been difficult to elucidate experimentally, but could be important for understanding structure-property relationships. Here, two classes of crystal structures are evaluated via atomistic molecular dynamics: extended chain structures, wherein the polymer backbones are highly extended in near-trans conformations, and adjacent reentry structures, wherein the polymer backbones conform in adjacent reentry loops near the site of each covalently-bonded acid group. Energies of relaxed structures and hydrogen bonding states are compared, and X-ray scattering and other experimental data is compared with the simulation results.

  11. Precision Hyperfine Structure of 2;^3P State of ^3He with External Magnetic

    NASA Astrophysics Data System (ADS)

    Wu, Qixue; Drake, G. W. F.

    2007-06-01

    The theory of the Zeeman effect can be used to extrapolate precise measurements for the fine structure or the hyperfine structure to zero-field strength. In the present work, the hyperfine structure of 2;^3P state of ^3He with external magnetic fields is precisely calculated. The values of the fields for 32 crossings and five anticrossings of the magnetic sublevels are theoretically predicted for magnetic field strengths up to 1 Tesla. The results are compared with experimental work. We include the linear terms, diamagnetic terms, and the 2̂ relativistic correction terms in the Zeeman Hamiltonian. All related matrix elements are calculated with high accuracy by the use of double basis set Hylleraas type variational wave functions[1,2].[1] Z. -C. Yan and G.W.F. Drake, Phys. Rev. A 50, R1980 (1994).[2] Q. Wu and G.W.F. Drake, J. Phys. B 40, 393 (2007).

  12. 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…

  13. Double Precision Differential/Algebraic Sensitivity Analysis Code

    Energy Science and Technology Software Center (ESTSC)

    1995-06-02

    DDASAC solves nonlinear initial-value problems involving stiff implicit systems of ordinary differential and algebraic equations. Purely algebraic nonlinear systems can also be solved, given an initial guess within the region of attraction of a solution. Options include automatic reconciliation of inconsistent initial states and derivatives, automatic initial step selection, direct concurrent parametric sensitivity analysis, and stopping at a prescribed value of any user-defined functional of the current solution vector. Local error control (in the max-normmore » or the 2-norm) is provided for the state vector and can include the sensitivities on request.« less

  14. Testing and application of a viscous passive damper for use in precision truss structures

    NASA Technical Reports Server (NTRS)

    Trubert, M.; Fanson, J.; Davis, P.; Anderson, E.

    1991-01-01

    A passive damping device intended to replace individual struts in precision truss structures for space applications is described. The theory of operation of the D-Strut device is detailed, and simple five- and three-parameter models are derived. Results from tests conducted to characterize the D-Strut at submicron displacement levels are reporeted. The incorporation of a strut in a precision truss testbed is described. Parameters determined from the component-level tests are used in a finite element model of the truss, and damping augmentation is predicted. Using the simple three-parameter model, a damper is selected for multiple placement in a separate optical interferometer truss testbed. The effect of the addition of the damper struts is illustrated analytically in a model of the structure. Finally, an improved Arched Flexure D-Strut that is expected to provide higher loss factors, and is currently under development, is described.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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…

  2. Characterization of Hertzian rolling microslip in precision revolute joints for deployable space structures

    NASA Astrophysics Data System (ADS)

    Jeon, Sungeun Ki

    2009-09-01

    The capabilities of space-born telescopes are primarily limited by their launch systems, dictating both light-gathering power and resolution, by constricting aperture size. Precision deployable space structure technology enables smaller stowed configurations for launch and a larger deployed operational state in space. The primary engineering difficulties arise from the accuracy and repeatability requirements of the deployed system, where an optical system requires tens of nanometers RMS surface displacement. Recent studies identify that instabilities and errors in a deployable space structure are primarily caused by the stick-slip friction between the contact interfaces of the latches and joints. The intent of this research is to model and characterize the nonlinearities of contact of a precision revolute joint for deployable space structures. The joint is a modified pin-clevis joint, where the deployment mechanism, load-path, and sources of instability are relegated to the contact interfaces of pair of angular contact bearings. This research presents a nonlinear lumped-parameter finite element modeling the nonlinear mechanics of contact to characterize the microdynamic behavior of the angular contact bearings for a precision revolute hinge. The mechanics of contact are based on Hertz contact theory and a numerical simulation subproblem based on the influence function method. The numerical simulation is rigorously validated and is shown to efficiently and effectively model transient rolling contact with varying normal contact forces, where current literature and numerical modeling techniques fail. The in uence of surface roughness and stochastic variations due to manufacturing and assembly are studied in regards to stiffness performance metrics. Rolling hysteresis is identified for various conditions, and a zero-loss rolling mechanism is discovered and investigated. Design implications, capabilities, recommendations, and optimal improvements for the precision hinge

  3. A flexile and high precision calibration method for binocular structured light scanning system.

    PubMed

    Yuan, Jianying; Wang, Qiong; Li, Bailin

    2014-01-01

    3D (three-dimensional) structured light scanning system is widely used in the field of reverse engineering, quality inspection, and so forth. Camera calibration is the key for scanning precision. Currently, 2D (two-dimensional) or 3D fine processed calibration reference object is usually applied for high calibration precision, which is difficult to operate and the cost is high. In this paper, a novel calibration method is proposed with a scale bar and some artificial coded targets placed randomly in the measuring volume. The principle of the proposed method is based on hierarchical self-calibration and bundle adjustment. We get initial intrinsic parameters from images. Initial extrinsic parameters in projective space are estimated with the method of factorization and then upgraded to Euclidean space with orthogonality of rotation matrix and rank 3 of the absolute quadric as constraint. Last, all camera parameters are refined through bundle adjustment. Real experiments show that the proposed method is robust, and has the same precision level as the result using delicate artificial reference object, but the hardware cost is very low compared with the current calibration method used in 3D structured light scanning system. PMID:25202736

  4. 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.

  5. 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.

  6. Analysis of Geological Structures

    NASA Astrophysics Data System (ADS)

    Price, Neville J.; Cosgrove, John W.

    1990-08-01

    A knowledge of structural geology is fundamental to understanding the processes by which the earth's crust has evolved. It is a subject of fundamental importance to students of geology, experienced field geologists and academic researchers as well as to petroleum and mining engineers. In contrast to many structural textbooks which dwell upon geometrical descriptions of geological structures, this book emphasises mechanical principles and the way in which they can be used to understand how and why a wide range of geological structures develop. Structures on all scales are considered but the emphasis of the book is on those that can be seen on the scale of hand specimen or outcrop. Drawing on their considerable teaching experience the authors present a coherent and lucid analysis of geological structures which will be welcomed by a wide variety of earth scientists.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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

    2014-01-01

    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. PMID:24916914

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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 ()/() corner towards the particle centre and expansion of a flat () 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.

  16. Precise, biomimetic replication of the multiscale structure of intestinal basement membrane using chemical vapor deposition.

    PubMed

    Pfluger, Courtney A; McMahon, Brian J; Carrier, Rebecca L; Burkey, Daniel D

    2013-03-01

    While it has been shown that cells respond to topographical cues, most studies of the influence of topography have been restricted to culture substrates with regular, single-scale features, such as grooves. In contrast, in vivo topography is highly complex, irregular, and multiscale. In this work, we demonstrate the use of chemical vapor deposition (CVD) on native tissue to fabricate a precise nonbiological replica of irregular macro-to-microscale biological topography. Specifically, the porcine intestinal basement membrane was decellularized and used as a template to create a silica replica from which tissue was removed to produce a free-standing topographically biomimetic silica film. Preservation of the crypt-villus structure (tens to hundreds of micrometers in scale), which is theorized to influence intestinal cell development and behavior, as well as the porosity of the native tissue membrane (1-5 μM in scale), was demonstrated; however, submicrometer topography appeared to be masked by ball-like structures believed to be a result of the CVD process. CVD process parameters, including reactor pressure and deposition temperature, were explored in efforts to enhance structural and mechanical integrity of the silica replica. A rigid inorganic replica can be used as a template for casting of biocompatible polymeric membranes; thus, this is the first step in fabricating cell culture substrates that precisely mimic their in vivo counterparts in terms of irregular, multiscale topography. PMID:23013380

  17. High precision atomic data for halo nuclei and related nuclear structure

    SciTech Connect

    Noertershaeuser, Wilfried

    2013-07-11

    Nuclear charge radii of the lightest neutron-halo isotopes {sup 6,8}He, {sup 11}Li, and {sup 11}Be have been measured during the last decade using tailored laser-spectroscopic techniques for the needs of high-accuracy isotope shift measurements on millisecond-isotopes with very low production yields. Nuclear charge radii can be extracted using high-precision calculations of the mass-shift contribution and the electronic factor of the finite-nuclear-size effect. These results are important benchmarks for nuclear structure theory and give access to the correlations between halo neutrons and average distances of the halo neutrons from the core nucleus.

  18. 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.

  19. Reference conditions for giant sequoia forest restoration: Structure, process, and precision

    USGS Publications Warehouse

    Stephenson, N.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.

  20. 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

  1. COI Structural Analysis Presentation

    NASA Technical Reports Server (NTRS)

    Cline, Todd; Stahl, H. Philip (Technical Monitor)

    2001-01-01

    This report discusses the structural analysis of the Next Generation Space Telescope Mirror System Demonstrator (NMSD) developed by Composite Optics Incorporated (COI) in support of the Next Generation Space Telescope (NGST) project. The mirror was submitted to Marshall Space Flight Center (MSFC) for cryogenic testing and evaluation. Once at MSFC, the mirror was lowered to approximately 40 K and the optical surface distortions were measured. Alongside this experiment, an analytical model was developed and used to compare to the test results. A NASTRAN finite element model was provided by COI and a thermal model was developed from it. Using the thermal model, steady state nodal temperatures were calculated based on the predicted environment of the large cryogenic test chamber at MSFC. This temperature distribution was applied in the structural analysis to solve for the deflections of the optical surface. Finally, these deflections were submitted for optical analysis and comparison to the interferometer test data.

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

    PubMed Central

    2013-01-01

    Background 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. Results 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. Conclusions Precisely colocalized interacting pigmentary and structural elements generate extensive

  3. 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.

  4. 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.

  5. A Precise Measurement of the Deuteron Elastic Structure Function A(A2)

    SciTech Connect

    Andrian Honegger

    1999-12-01

    During summer 1997 experiment 394-018 measured the deuteron tensor polarization in D(e,e'd) scattering in Hall C at Jefferson Laboratory. In a momentum transfer range between 0.66 and 1:8 (GeV=c){sup 2}, with slight changes in the experimental setup, the collaboration performed six precision measurements of the deuteron structure function A(Q{sup 2}) 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. 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

  7. 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

    2015-01-01

    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

  8. A 3.6 nm Ti52-Oxo Nanocluster with Precise Atomic Structure.

    PubMed

    Fang, Wei-Hui; Zhang, Lei; Zhang, Jian

    2016-06-22

    We report a 3.6 nm Ti52-oxo cluster with precise atomic structure, which presents a largest size record in the family of titanium-oxo clusters (TOCs). The crystal growth of such large Ti52 is based on a stepwise interlayer assembly approach from Ti6 substructures. The possible growth mechanism of Ti52 could be deduced from crystal structures of two substructures, Ti6 and Ti17, which were also synthesized under similar conditions as Ti52. Moreover, these TOCs show cluster-size-dependent photocatalytic hydrogen evolution activities with Ti52 giving a H2 production rate up to 398 μmol/h/g, which is also the highest record in the family of TOCs. This work not only represents a milestone in constructing large TOCs with comparable sizes as TiO2 nanoparticles but also brings significant advances in improving photocatalytic behaviors of TOCs. PMID:27248658

  9. 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.

  10. 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.

  11. 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.

  12. Calculation and analysis for stiffness of the thrust aerostatic bearing of ultra-precision machine tools

    NASA Astrophysics Data System (ADS)

    Lu, Lihua; Zhao, Ziqiang; Liang, Yingchun; Zhang, Longjiang

    2010-10-01

    The single point diamond turning (SPDT) lathe of vertical flying cutting milling style is one important ultra-precision machining method for Large-aperture optics. To realize ultra-precision machining with SPDT technology, the turning spindle of the machine tools should be with higher stiffness and stability. In this paper, based on finite element method (FEM), an iterative procedure is proposed and implemented to solve the fluid dynamic model and structure model for simulation the couple of air pressure and structure flexibility. Simulation results show that pressure in the air gap makes the plate deform and this deformation produced by the pressure adversely modifies the pressure distribution. Experimental results indicate that the method can predict the aerostatic spindle stiffness accurately, the prediction error is about 2.04%. These results show a relevant influence of the structural flexibility of the bearing on its static performance.

  13. Computational engine structural analysis

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Johns, R. H.

    1986-01-01

    A significant research activity at the NASA Lewis Research Center is the computational simulation of complex multidisciplinary engine structural problems. This simulation is performed using computational engine structural analysis (CESA) which consists of integrated multidisciplinary computer codes in conjunction with computer post-processing for problem-specific application. A variety of the computational simulations of specific cases are described in some detail in this paper. These case studies include: (1) aeroelastic behavior of bladed rotors, (2) high velocity impact of fan blades, (3) blade-loss transient response, (4) rotor/stator/squeeze-film/bearing interaction, (5) blade-fragment/rotor-burst containment, and (6) structural behavior of advanced swept turboprops. These representative case studies are selected to demonstrate the breath of the problems analyzed and the role of the computer including post-processing and graphical display of voluminous output data.

  14. 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

  15. 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.

  16. 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

  17. Structured Data in Structural Analysis Software

    NASA Technical Reports Server (NTRS)

    Kunz, Donald L.; Hopkins, Stewart

    1987-01-01

    This paper discusses the use of computer data structures in finite-element structural analysis programs. A number of data structure types that have been shown to be useful in such programs are introduced and described. A simple finite-element model is used to demonstrate how the given set of data structure types naturally lend themselves to developing software for the model. Different methods of implementing data structures in the context of a program are discussed.

  18. 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

  19. 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. PMID:24995148

  20. Highly precise distributed Brillouin scattering sensor for structural health monitoring of optical ground wire cable

    NASA Astrophysics Data System (ADS)

    Zou, Lufan; Ravet, Fabien; Bao, Xiaoyi; Chen, Liang

    2004-07-01

    A distributed Brillouin scattering sensor with high special precision has been developed for the measurement of small damages/cracks of 1.5 cm. The out-layer damaged regions in an optical ground wire (OPGW) cable have been identified successfully by measuring the strain distributions every 5 cm using this technology. The stress increased to 127 kN which corresponds to more than 7500 micro-strain in the fibers. The locations of structural indentations comprising repaired and undamaged regions are found and distinguished using their corresponding strain data. The elongation of repaired region increases with time on 127 kN. These results are quantified in terms of the fiber orientation, stress, and behavior relative to undamaged sections.

  1. Precision hyperfine structure spectroscopy of Be isotopes at SLOWRI prototype and prospects of SLOWRI at RIKEN

    SciTech Connect

    Wada, M.; Takamine, A.; Okada, K.; Sonoda, T.; Schury, P.; Kanai, Y.; Kojima, T. M.; Yamazaki, Y.; Yoshida, A.; Kubo, T.; Iimura, H.; Katayama, I.; Ohtani, S.; Wollnik, H.; Schuessler, H. A.

    2009-05-04

    Precision atomic spectroscopy experiments for Be isotopes have been carried out at the prototype universal slow RI-beam (SLOWRI) setup at RIKEN. Radioactive Be ions produced at 1 GeV were decelerated and thermlized in an RF-carpet ion guide. The thermalized ions were transferred to an ion trap where laser cooling was used to reduce the ion energy to the order of 1 {mu}eV. Laser microwave double resonance spectroscopy was performed for the hyperfine structure measurements of trapped and laser cooled {sup 7}Be{sup +} and {sup 11}Be{sup +} ions. Measurements of the S{sub 1/2}{yields}P{sub 1/2},P{sub 3/2} transition frequencies of {sup 7,9,10,11}Be{sup +} ions are also in progress. These results are briefly discussed. Future prospects for expanding the capability of SLOWRI is also discussed.

  2. 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

    2014-01-01

    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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. Stochastic precision analysis of two-dimensional cardiac strain estimation in vivo

    PubMed Central

    Bunting, EA; Provost, J; Konofagou, EE

    2014-01-01

    Ultrasonic strain imaging has been applied to echocardiography and carries great potential to be used as a tool in the clinical setting. Two-dimensional (2-D) strain estimation may be useful when studying the heart due to the complex, three-dimensional deformation of the cardiac tissue. Increasing the framerate used for motion estimation, i.e. motion estimation rate (MER), has been shown to improve the precision of the strain estimation, although maintaining the spatial resolution necessary to view the entire heart structure in a single heartbeat remains challenging at high MERs. Two previously developed methods, the temporally unequispaced acquisition sequence (TUAS) and the diverging beam sequence (DBS), have been used in the past to successfully estimate in vivo axial strain at high MERs without compromising spatial resolution. In this study, a stochastic assessment of 2-D strain estimation precision is performed in vivo for both sequences at varying MERs (65, 272, 544, 815 Hz for TUAS; 250, 500, 1000, 2000 Hz for DBS). 2-D incremental strains were estimated in five healthy volunteers using a normalized cross-correlation function and a least-squares strain estimator. Both sequences were shown capable of estimating 2-D incremental strains in vivo. The conditional expected value of the elastographic signal-to-noise ratio (E(SNRe|ε)) was used to compare strain estimation precision of both sequences at multiple MERs over a wide range of clinical strain values. The results here indicate that axial strain estimation precision is much more dependent on MER than lateral strain estimation, while lateral estimation is more affected by strain magnitude. MER should be increased at least above 544 Hz to avoid suboptimal axial strain estimation. Radial and circumferential strain estimations were influenced by the axial and lateral strain in different ways. Furthermore, the TUAS and DBS were found to be of comparable precision at similar MERs. PMID:25330746

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Atomically precise self-assembly of one-dimensional structures on silicon

    NASA Astrophysics Data System (ADS)

    Barke, I.; Rügheimer, T. K.; Zheng, Fan; Himpsel, F. J.

    2007-10-01

    This work has three main themes: (1) fabricate atomically precise nanostructures at surfaces, particularly nanowires consisting of atom chains; (2) explore the behavior of one-dimensional electrons in atomic chains; (3) find the fundamental limits of data storage using an atomic scale memory. Semiconductor surfaces lend themselves towards self-assembly, because the broken covalent bonds create elaborate reconstruction patterns to minimize the surface energy. An example is the large 7 × 7 unit cell on Si(1 1 1), which can be used as building block. On semiconductors, the surface electrons completely de-couple from the substrate, as long as their energy lies in the band gap. Angle-resolved photoemission reveals surprising features, such as a fractional band filling and a spin-splitting at a non-magnetic surface. An interesting by-product is a memory structure with self-assembled tracks that are five atom rows wide and store a bit by the presence or absence of a single silicon atom. This toy memory is used to test the fundamental limits of data storage and to see how storage on silicon compares to storage in DNA.

  14. A Generalized Functional Model Based Method for Vibration-Based Damage Precise Localization in 3D Structures

    NASA Astrophysics Data System (ADS)

    Sakaris, Christos S.; Sakellariou, John S.; Fassois, Spilios D.

    2015-07-01

    A Generalized Functional Model Based Method for vibration-based damage precise localization on structures consisting of 1D, 2D, or 3D elements is introduced. The method generalizes previous versions applicable to structures consisting of 1D elements, thus allowing for 2D and 3D elements as well. It is based on scalar (single sensor) or vector (multiple sensor) Functional Models which - in the inspection phase - incorporate the mathematical form of the specific structural topology. Precise localization is then based on coordinate estimation within this model structure, and confidence bounds are also obtained. The effectiveness of the method is demonstrated through experiments on a 3D truss structure where damage corresponds to single bolt loosening. Both the scalar and vector versions of the method are shown to be effective even within a very limited, low frequency, bandwidth of 3-59 Hz. The improvement achieved through the use of multiple sensors is also demonstrated.

  15. 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.

  16. 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.

  17. Geostatistical analysis of the soil and crop parameters in a field experiment on precision agriculture

    NASA Astrophysics Data System (ADS)

    Sidorova, V. A.; Zhukovskii, E. E.; Lekomtsev, P. V.; Yakushev, V. V.

    2012-08-01

    A thorough geostatistical analysis was performed of the spatial variability of the soil properties, the sowing parameters, and the wheat yield in a field experiment under precision agriculture conditions. It was found that most of the soil parameters are significantly correlated and can be successfully mapped using kriging procedures, which ensure the optimum development of agrochemical cartograms for agricultural fields. It was also shown that the sowing parameters had a significantly lower spatial correlation; their cartograms could be drawn, although with worse accuracy. The quality parameters of the wheat grain showed no spatial correlation.

  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. Precision measurement of the neutron spin asymmetries and spin-dependent structure functions in the valence quark region

    SciTech Connect

    Zheng, X.; Bertozzi, W.; Chai, Z.; Dutta, D.; Gao, H.; Gilad, S.; Higinbotham, D.W.; Rvachev, M.; Sirca, S.; Xiang, H.; Xiao, Y.; Xiong, F.; Zhang, B.; Zhu, L.; Aniol, K.; Margaziotis, D.J.; Armstrong, D.S.; Butuceanu, C.; Finn, J.M.; Kramer, K.

    2004-12-01

    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 0.60 and Q{sup 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 2. 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.

  20. Combination of structural reliability and interval analysis

    NASA Astrophysics Data System (ADS)

    Qiu, Zhiping; Yang, Di; Elishakoff, Isaac

    2008-02-01

    In engineering applications, probabilistic reliability theory appears to be presently the most important method, however, in many cases precise probabilistic reliability theory cannot be considered as adequate and credible model of the real state of actual affairs. In this paper, we developed a hybrid of probabilistic and non-probabilistic reliability theory, which describes the structural uncertain parameters as interval variables when statistical data are found insufficient. By using the interval analysis, a new method for calculating the interval of the structural reliability as well as the reliability index is introduced in this paper, and the traditional probabilistic theory is incorporated with the interval analysis. Moreover, the new method preserves the useful part of the traditional probabilistic reliability theory, but removes the restriction of its strict requirement on data acquisition. Example is presented to demonstrate the feasibility and validity of the proposed theory.

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

    PubMed

    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

  2. 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

  3. 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

  4. 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.

  5. Estimating sparse precision matrices

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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/√{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/√{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.

  6. 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/√{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/√{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.

  7. 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).

  8. 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.

  9. 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.

  10. 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.

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

    SciTech Connect

    Logan, J.; Logan, J.; Alexoff, D.; Fowler, J.S.

    2010-09-01

    Graphical analysis (GA) is an efficient method for estimating total tissue distribution volume (V{sub T}) from positron emission tomography (PET) uptake data. The original GA produces a negative bias in V{sub T} in the presence of noise. Estimates of V{sub 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{sub T}'s ranging from 10.5 to 64 mL/cm{sub 3} and from PET image data with the tracer [{sup 11}C]DASB ([{sup 11}C]-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl) benzonitrile). Four estimates of V{sub 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.

  12. 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. PMID:20480922

  13. 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.

  14. Design, development and mechanization of a precision deployable truss with optimized structural efficiency for spaceborne applications

    NASA Technical Reports Server (NTRS)

    Craighead, N. D.; Hult, T. D.; Preliasco, R. J.

    1982-01-01

    A deployable mast concept which meets the weight, size and stability requirements for a feed support structure for offset antennas up to 100 meters in diameter is discussed. A triangulated truss configuration, the use of tapered tubes which exhibit a high strength-to-weight ratio, and low CTE graphite-epoxy material are seen to provide an efficient, lightweight and stable truss suitable for an antenna feed support. A low stowage ratio of 30:1 is achieved through a unique preloaded hinge located at the center of each longeron and an autonomous deployment cage with a drive mechanism. Initial analysis and proof of concept hardware validated the basic mechanism and design assumptions and provided a basis for further investigation. The concept can readily accept variations in member size and thus lends itself to optimization for other potential uses where a stiff, lightweight deployable truss is needed.

  15. 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.

  16. 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. PMID:26337122

  17. Measurement system and precision analysis for bending and twisting properties evaluation of textile fabrics

    NASA Astrophysics Data System (ADS)

    Yao, Bao-guo; Zhang, Shan; Yang, Yun-juan; Zhang, De-pin

    2016-01-01

    A new test method and a measurement system was proposed and developed to evaluate the bending and twisting properties of textile fabrics. The measurement system and the test method is based on the mechanical device, sensors and microelectronics and simulates the dynamic process during the fabric is bent and twisted. The virtual instrument based system can measure the dynamic changes of the signals due to the bending and twisting loads. Derived from the test data, a series of indices are defined to characterize the bending and twisting properties. The test and evaluation method, the experiments and the test results are reported. The analysis of the variance for intra-laboratory test was performed to determine the precisions of the test method and the measurement system. The measurement system provides a method for objective measurement and evaluation of bending and twisting properties of textile fabrics.

  18. 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.

  19. Active member control of a precision structure with an H(infinity) performance objective

    NASA Technical Reports Server (NTRS)

    Fanson, J. L.; Chu, C.-C.; Smith, R. S.; Anderson, E. H.

    1990-01-01

    This paper addresses the noncollocated control of active structures using active structural elements. A top level architecture for active structures is presented, and issues pertaining to robust control of structures are discussed. Controllers optimized for an H sub inf performance specification are implemented on a test structure and the results are compared with analytical predictions. Directions for further research are identified.

  20. Online high-precision delta(2)H and delta(18)O analysis in water by pyrolysis.

    PubMed

    Lu, Feng H

    2009-10-01

    A method for online simultaneous delta(2)H and delta(18)O analysis in water by high-temperature conversion is presented. Water is injected by using a syringe into a high-temperature carbon reactor and converted into H(2) and CO, which are separated by gas chromatography (GC) and carried by helium to the isotope ratio mass spectrometer for hydrogen and oxygen isotope analysis. A series of experiments was conducted to evaluate several issues such as sample size, temperature and memory effects. The delta(2)H and delta(18)O values in multiple water standards changed consistently as the reactor temperature increased from 1150 to 1480 degrees C. The delta(18)O in water can be measured at a lower temperature (e.g. 1150 degrees C) although the precision was relatively poor at temperatures <1300 degrees C. Memory effects exist for delta(2)H and delta(18)O between two waters, and can be reduced (to <1%) with proper measures. The injection of different amounts of water may affect the isotope ratio results. For example, in contrast to small injections (100 nL or less) from small syringes (e.g. 1.2 microL), large injections (1 microL or more) from larger syringes (e.g. 10 microL) with dilution produced asymmetric peaks and shifts of isotope ratios, e.g. 4 per thousand for delta(2)H and 0.4 per thousand for delta(18)O, probably resulting from isotope fractionation during dilution via the ConFlo interface. This method can be used to analyze nanoliter samples of water (e.g. 30 nL) with good precision of 0.5 per thousand for delta(2)H and 0.1 per thousand for delta(18)O. This is important for geosciences; for instance, fluid inclusions in ancient minerals may be analyzed for delta(2)H and delta(18)O to help understand the formation environments. PMID:19714707

  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. Real-time GPS seismology using a single receiver: method comparison, error analysis and precision validation

    NASA Astrophysics Data System (ADS)

    Li, Xingxing

    2014-05-01

    Earthquake monitoring and early warning system for hazard assessment and mitigation has traditional been based on seismic instruments. However, for large seismic events, it is difficult for traditional seismic instruments to produce accurate and reliable displacements because of the saturation of broadband seismometers and problematic integration of strong-motion data. Compared with the traditional seismic instruments, GPS can measure arbitrarily large dynamic displacements without saturation, making them particularly valuable in case of large earthquakes and tsunamis. GPS relative positioning approach is usually adopted to estimate seismic displacements since centimeter-level accuracy can be achieved in real-time by processing double-differenced carrier-phase observables. However, relative positioning method requires a local reference station, which might itself be displaced during a large seismic event, resulting in misleading GPS analysis results. Meanwhile, the relative/network approach is time-consuming, particularly difficult for the simultaneous and real-time analysis of GPS data from hundreds or thousands of ground stations. In recent years, several single-receiver approaches for real-time GPS seismology, which can overcome the reference station problem of the relative positioning approach, have been successfully developed and applied to GPS seismology. One available method is real-time precise point positioning (PPP) relied on precise satellite orbit and clock products. However, real-time PPP needs a long (re)convergence period, of about thirty minutes, to resolve integer phase ambiguities and achieve centimeter-level accuracy. In comparison with PPP, Colosimo et al. (2011) proposed a variometric approach to determine the change of position between two adjacent epochs, and then displacements are obtained by a single integration of the delta positions. This approach does not suffer from convergence process, but the single integration from delta positions to

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. CODSTRAN - Composite durability structural analysis

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Smith, G. T.

    1978-01-01

    CODSTRAN (COmposite Durability STRucture ANalysis) a NASA Lewis Center computer program for the prediction of defect growth and fracture of composite structures when subjected to service loads is presented. Organization, capabilities and present status are discussed. Organizational aspects include executive, input, output, analysis and composite mechanics modules. Capabilities include: durability assessment of large structures and complex structural parts from composites, structural response due to static, cyclic, transient impact and thermal loads, and criteria for static, cyclic, and dynamic fracture. At the present state of development some of CODSTRAN's analysis capabilities include composite mechanics, static failures, and lamination residual stresses. An application in which CODSTRAN is used to predict the defect growth in a flat specimen, with a center through-slit under tension is studied. When completed, CODSTRAN will account for geometry and material nonlinearities, environmental effects as well as static, cyclic and dynamic fracture.

  10. 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

  11. 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

  12. 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

  13. 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…

  14. High-precision hyperfine structure measurement in slow atomic ion beams by collinear laser-rf double resonance

    SciTech Connect

    Amarjit Sen, Childs, W.J.; Goodman, L.S.

    1987-01-01

    A new collinear laser-ion beam apparatus for slow ions (1 to 1.5 keV) has been built for measuring the hyperfine structure of metastable levels of ions with laser-rf double resonance technique. Narrow linewidths of approx.60 kHz (FWHM) have been observed for the first time in such systems. As a first application the hyperfine structure of the 4f/sup 7/(/sup 8/S/sup 0/)5d /sup 9/D/sub J//sup 0/ metastable levels of /sup 151,153/Eu/sup +/ has been measured with high precision. 10 refs., 8 figs.

  15. Methods for the Analysis of High Precision Differential Hydrogen Deuterium Exchange Data

    PubMed Central

    Chalmers, Michael J.; Pascal, Bruce D.; Willis, Scooter; Zhang, Jun; Iturria, Stephen J.; Dodge, Jeffery A.; Griffin, Patrick R.

    2010-01-01

    Hydrogen/deuterium exchange (HDX) mass spectrometry has been widely applied to the characterization of protein dynamics. More recently, differential HDX has been shown to be effective for the characterization of ligand binding. Previously we have described a fully automated HDX system for use as a ligand screening platform. Here we describe and validate the required data analysis workflow to facilitate the use of HDX as a robust approach for ligand screening. Following acquisition of HDX data at a single on-exchange time point (n ≥ 3), one way analysis of variance in conjunction with the Tukey multiple comparison procedure is used to establish the significance of any measured difference. Analysis results are graphed with respect to a single peptide, ligand or group of ligands, or displayed as an overview within a heat map. For the heat map display, only Δ%D values with a Tukey-adjusted P value less than 0.05 are colored. Hierarchical clustering is used to bin compounds with highly similar HDX signatures. The workflow is evaluated with a small data set showing the ligand binding domain (LDB) of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) screened against 10 functionally selective ligands. More significantly, data for the vitamin D receptor (VDR) in complex with 87 ligands are presented. To highlight the robustness and precision of our automated HDX platform we analyzed the data from 4191 replicate HDX measurements acquired over an eight month timeframe. Ninety six percent of these measurements were within 10 percent of the mean value. Work has begun to integrate these analysis and graphing components within our HDX software suite. PMID:21528013

  16. High-precision position-specific isotope analysis of 13C/12C in leucine and methionine analogues.

    PubMed

    Sacks, Gavin L; Brenna, J Thomas

    2003-10-15

    We report an automated method for high-precision position-specific isotope analysis (PSIA) of carbon in amino acid analogues. Carbon isotope ratios are measured for gas-phase pyrolysis fragments from multiple sources of 3-methylthiopropylamine (3MTP) and isoamylamine (IAA), the decarboxylated analogues of methionine and leucine, using a home-built gas chromatography (GC)-pyrolysis-GC preparation system coupled to a combustion-isotope ratio mass spectrometry system. Over a temperature range of 620-900 degrees C, the characteristic pyrolysis products for 3MTP were CH4, C2H6, HCN, and CH3CN and for IAA products were propylene, isobutylene, HCN, and CH3CN. Fragment origin was confirmed by 13C-labeling, and fragments used for isotope analysis were generated from unique moieties with > 95% structural fidelity. Isotope ratios for the fragments were determined with an average precision of SD(delta13C) < 0.3% per thousand, and relative isotope ratios of fragments from different sources were determined with an average precision of SD(delta(delta)13C) < 0.5% per thousand. Delta(delta)13C values of fragments were invariant over a range of pyrolysis temperatures. The delta(delta)13C of complementary fragments in IAA was within 0.8% per thousand of the delta(delta)13C of the parent compounds, indicating that pyrolysis-induced isotopic fractionation is effectively taken into account with this calibration procedure. Using delta(delta)13C values of fragments, delta(delta)13C values were determined for all four carbon positions of 3MTP and for C1, C2, and the propyl moiety of IAA, either directly or indirectly by mass balance. Large variations in position-specific isotope ratios were observed in samples from different commercial sources. Most dramatically, two 3MTP sources differed by 16.30% per thousand at C1, 48.33% per thousand at C2, 0.37% per thousand at C3, and 5.36% per thousand at C(methyl). These PSIA techniques are suitable for studying subtle changes in intramolecular

  17. Real-space electronic structure calculations with full-potential all-electron precision for transition metals

    NASA Astrophysics Data System (ADS)

    Ono, Tomoya; Heide, Marcus; Atodiresei, Nicolae; Baumeister, Paul; Tsukamoto, Shigeru; Blügel, Stefan

    2010-11-01

    We have developed an efficient computational scheme utilizing the real-space finite-difference formalism and the projector augmented-wave (PAW) method to perform precise first-principles electronic-structure simulations based on the density-functional theory for systems containing transition metals with a modest computational effort. By combining the advantages of the time-saving double-grid technique and the Fourier-filtering procedure for the projectors of pseudopotentials, we can overcome the egg box effect in the computations even for first-row elements and transition metals, which is a problem of the real-space finite-difference formalism. In order to demonstrate the potential power in terms of precision and applicability of the present scheme, we have carried out simulations to examine several bulk properties and structural energy differences between different bulk phases of transition metals and have obtained excellent agreement with the results of other precise first-principles methods such as a plane-wave-based PAW method and an all-electron full-potential linearized augmented plane-wave (FLAPW) method.

  18. 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.

  19. 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

  20. 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).

  1. 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.

  2. Improving the precision of fMRI BOLD signal deconvolution with implications for connectivity analysis.

    PubMed

    Bush, Keith; Cisler, Josh; Bian, Jiang; Hazaroglu, Gokce; Hazaroglu, Onder; Kilts, Clint

    2015-12-01

    An important, open problem in neuroimaging analyses is developing analytical methods that ensure precise inferences about neural activity underlying fMRI BOLD signal despite the known presence of confounds. Here, we develop and test a new meta-algorithm for conducting semi-blind (i.e., no knowledge of stimulus timings) deconvolution of the BOLD signal that estimates, via bootstrapping, both the underlying neural events driving BOLD as well as the confidence of these estimates. Our approach includes two improvements over the current best performing deconvolution approach; 1) we optimize the parametric form of the deconvolution feature space; and, 2) we pre-classify neural event estimates into two subgroups, either known or unknown, based on the confidence of the estimates prior to conducting neural event classification. This knows-what-it-knows approach significantly improves neural event classification over the current best performing algorithm, as tested in a detailed computer simulation of highly-confounded fMRI BOLD signal. We then implemented a massively parallelized version of the bootstrapping-based deconvolution algorithm and executed it on a high-performance computer to conduct large scale (i.e., voxelwise) estimation of the neural events for a group of 17 human subjects. We show that by restricting the computation of inter-regional correlation to include only those neural events estimated with high-confidence the method appeared to have higher sensitivity for identifying the default mode network compared to a standard BOLD signal correlation analysis when compared across subjects. PMID:26226647

  3. CODSTRAN: Composite durability structural analysis

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Smith, G. T.

    1978-01-01

    CODSTRAN (COmposite Durability STRuctural ANalysis) is an integrated computer program being developed for the prediction of defect growth and fracture of composite structures subjected to service loads and environments. CODSTRAN is briefly described with respect to organization, capabilities and present status. Application of CODSTRAN current capability to a flat composite laminate with a center slit which was subjected to axial tension loading predicted defect growth which is in good agreement with C-scan ultrasonic test records.

  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. Precise laser frequency scanning using frequency-synthesized optical frequency sidebands - Application to isotope shifts and hyperfine structure of mercury

    NASA Technical Reports Server (NTRS)

    Rayman, M. D.; Aminoff, C. G.; Hall, J. L.

    1989-01-01

    Based on an efficient broadband electrooptic modulator producing RF optical sidebands locked to a stable cavity, a tunable dye laser can be scanned under computer control with frequency-synthesizer precision. Cavity drift is suppressed in software by using a strong feature in the spectrum for stabilization. Mercury isotope shifts are measured with a reproducibility of about 50 kHz. This accuracy of about 1/300 of the linewidth illustrates the power of the technique. Derived hyperfine-structure constants are compared with previous atomic-beam data.

  6. 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

  7. 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. PMID:23184622

  8. 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.

  9. 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...

  10. 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.

  11. Use of glass ceramic as a structural material for a high-precision space telescope

    NASA Astrophysics Data System (ADS)

    Juranek, Hans J.; Kleer, G.; Doell, W.

    1994-09-01

    SILEX is the acronym for Satellite InterLink EXperiment. By this experiment ESA (European Space Agency) starts the optical communication technique in space. Similar to the usual RF-communication technique the optical technique requires antennas for transmitting and receiving signals. Such antennas are telescopes. For Silex a two mirror telescope of an aperture of 250 mm was specified. To gain the benefits of optical communication such a telescope must fulfil extreme optical performances, especially concerning the wavefront quality which is strongly governed by the stability of the telescope structure. Thus the structure of SILEX telescope must guarantee a stability of +/- 2 microns over 320 mm in length. This figure must be maintained for 10 years under extreme environmental conditions, this especially concerns temperature, irradiation, ageing and above all launch loads. Looking at this area the glass ceramic ZERODUR was a very promising material to be used as a structural material provided one overcomes the justified concern on its mechanical reliability due to the fact that it is a brittle material similar to glass. This contribution presents solutions of the basic problems in structural design, the means of material and process qualification, and final qualification against launch loads of the critical structural item.

  12. Structural analysis of aligned RNAs.

    PubMed

    Voss, Björn

    2006-01-01

    The knowledge about classes of non-coding RNAs (ncRNAs) is growing very fast and it is mainly the structure which is the common characteristic property shared by members of the same class. For correct characterization of such classes it is therefore of great importance to analyse the structural features in great detail. In this manuscript I present RNAlishapes which combines various secondary structure analysis methods, such as suboptimal folding and shape abstraction, with a comparative approach known as RNA alignment folding. RNAlishapes makes use of an extended thermodynamic model and covariance scoring, which allows to reward covariation of paired bases. Applying the algorithm to a set of bacterial trp-operon leaders using shape abstraction it was able to identify the two alternating conformations of this attenuator. Besides providing in-depth analysis methods for aligned RNAs, the tool also shows a fairly well prediction accuracy. Therefore, RNAlishapes provides the community with a powerful tool for structural analysis of classes of RNAs and is also a reasonable method for consensus structure prediction based on sequence alignments. RNAlishapes is available for online use and download at http://rna.cyanolab.de. PMID:17020924

  13. Structural Analysis in the Classroom

    ERIC Educational Resources Information Center

    Gage, Nicholas A.; Lewis, Timothy J.

    2010-01-01

    The purpose of this article is to describe an applied method of assessing and manipulating environmental factors influencing student behavior. The assessment procedure is called structural analysis (SA) and can be a part of a functional behavioral assessment (FBA) process or a stand-alone set of procedures for teachers to use in their classrooms.…

  14. 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…

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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. PMID:17474528

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

    USGS Publications Warehouse

    Prejean, S.; Stork, A.; Ellsworth, W.; Hill, D.; Julian, B.

    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. Copyright 2003 by the American Geophysical Union.

  2. 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.

  3. Precision of radiostereometric analysis (RSA) of acetabular cup stability and polyethylene wear improved by adding tantalum beads to the liner

    PubMed Central

    Nebergall, Audrey K; Rader, Kevin; Palm, Henrik; Malchau, Henrik; Greene, Meridith E

    2015-01-01

    Background and purpose In traditional radiostereometric analysis (RSA), 1 segment defines both the acetabular shell and the polyethylene liner. However, inserting beads into the polyethylene liner permits employment of the shell and liner as 2 separate segments, enabling distinct analysis of the precision of 3 measurement methods in determining femoral head penetration and shell migration. Patients and methods The UmRSA program was used to analyze the double examinations of 51 hips to determine if there was a difference in using the shell-only segment, the liner-only segment, or the shell + liner segment to measure wear and acetabular cup stability. The standard deviation multiplied by the critical value (from a t distribution) established the precision of each method. Results Due to the imprecision of the automated edge detection, the shell-only method was least desirable. The shell + liner and liner-only methods had a precision of 0.115 mm and 0.086 mm, respectively, when measuring head penetration. For shell migration, the shell + liner had a precision of 0.108 mm, which was better than the precision of the shell-only method. In both the penetration and migration analyses, the shell + liner condition number was statistically significantly lower and the bead count was significantly higher than for the other methods. Interpretation Insertion of beads in the polyethylene improves the precision of femoral head penetration and shell migration measurements. A greater dispersion and number of beads when combining the liner with the shell generated more reliable results in both analyses, by engaging a larger portion of the radiograph. PMID:26012546

  4. 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).

  5. 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.

  6. 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

  7. Structured functional principal component analysis.

    PubMed

    Shou, Haochang; Zipunnikov, Vadim; Crainiceanu, Ciprian M; Greven, Sonja

    2015-03-01

    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

  8. 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.

  9. Analysis on the detection performance of BOTDR in small-scale precision engineering

    NASA Astrophysics Data System (ADS)

    Wang, Shuai; Luan, Lijun

    2013-12-01

    In this thesis, the authors discuss the detection performance of the small-scale precision engineering with the Brillouin scattering light on the base of experiments. The authors made the measurements using the traditional Strain Distribution Gauge and optical fiber scattering light shift equipment AQ8603 and obtained two results. The authors compared and analyzed the data and made the conclusion that the BOTDR technology is not suitable for the small-scale Precision Engineering. The wiring methods and their effects to detection performance are also been discussed in this thesis.

  10. Ab Initio Structure Analysis Using Laboratory Powder Diffraction Data

    NASA Astrophysics Data System (ADS)

    Sasaki, Akito

    Today, laboratory X-ray diffractometers are seeing increasingly wide use in the ab initio crystal structure analysis of organic powder samples. This is because optics and optical devices have been improved, making it possible to obtain precise integrated intensities of reflections in high 2-theta ranges. Another reason is that one can use direct-space methods, which do not require “high-resolution diffraction data”, much more easily than before. Described here are some key points to remember when performig ab initio crystal structure analysis using powder diffraction data from organic compounds.

  11. Diamond tool wear detection method using cutting force and its power spectrum analysis in ultra-precision fly cutting

    NASA Astrophysics Data System (ADS)

    Zhang, G. Q.; To, S.

    2014-08-01

    Cutting force and its power spectrum analysis was thought to be an effective method monitoring tool wear in many cutting processes and a significant body of research has been conducted on this research area. However, relative little similar research was found in ultra-precision fly cutting. In this paper, a group of experiments were carried out to investigate the cutting forces and its power spectrum characteristics under different tool wear stages. Result reveals that the cutting force increases with the progress of tool wear. The cutting force signals under different tool wear stages were analyzed using power spectrum analysis. The analysis indicates that a characteristic frequency does exist in the power spectrum of the cutting force, whose power spectral density increases with the increasing of tool wear level, this characteristic frequency could be adopted to monitor diamond tool wear in ultra-precision fly cutting.

  12. Uncertainty Analysis of Composite Structures

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Starnes, James H., Jr.; Peters, Jeanne M.

    2000-01-01

    A two-phase approach and a computational procedure are presented for predicting the variability in the nonlinear response of composite structures associated with variations in the geometric and material parameters of the structure. In the first phase, hierarchical sensitivity analysis is used to identify the major parameters, which have the most effect on the response quantities of interest. In the second phase, the major parameters are taken to be fuzzy parameters, and a fuzzy set analysis is used to determine the range of variation of the response, associated with preselected variations in the major parameters. The effectiveness of the procedure is demonstrated by means of a numerical example of a cylindrical panel with four T-shaped stiffeners and a circular cutout.

  13. 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.

  14. 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.

  15. 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. PMID:26918895

  16. 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.

  17. Neutron diffraction as a precise and reliable method for obtaining structural properties of bulk quantities of graphene

    NASA Astrophysics Data System (ADS)

    Sofer, Zdeněk; Šimek, Petr; Jankovský, Ondřej; Sedmidubský, David; Beran, Přemysl; Pumera, Martin

    2014-10-01

    Graphene based carbon materials have attracted a great deal of attention in the last decade; nowadays tons of graphene are produced yearly. However, there is lack of precise and reliable techniques for the determination of structural properties of graphene on the bulk scale. The analytical methods being routinely applied for graphene characterization, including TEM and AFM, can be only used for the study of scant amounts of graphene samples and do not give general information on the average number of layers and the structure of the prepared graphenes. On the other hand, diffraction methods can be advantageously used to obtain information on the average thickness of the produced graphene as well as on the average sheets lateral dimensions, without the necessity of sample dispersion in solvents. We present a study of the structural properties of graphene prepared by chemical and thermal reduction of graphite oxide, comparing SEM, STEM, AFM, Raman spectroscopy, BET, X-ray and neutron diffraction methods. Our study brings new deep insights into the basic structural properties of graphene in a bulk form. Given the importance of a suitable characterization technique on the bulk materials, we wish to highlight the importance of these diffraction techniques for accurate determination of the graphene thickness and lateral parameters.

  18. Grid Stiffened Structure Analysis Tool

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Grid Stiffened Analysis Tool contract is contract performed by Boeing under NASA purchase order H30249D. The contract calls for a "best effort" study comprised of two tasks: (1) Create documentation for a composite grid-stiffened structure analysis tool, in the form of a Microsoft EXCEL spread sheet, that was developed by originally at Stanford University and later further developed by the Air Force, and (2) Write a program that functions as a NASTRAN pre-processor to generate an FEM code for grid-stiffened structure. In performing this contract, Task 1 was given higher priority because it enables NASA to make efficient use of a unique tool they already have; Task 2 was proposed by Boeing because it also would be beneficial to the analysis of composite grid-stiffened structures, specifically in generating models for preliminary design studies. The contract is now complete, this package includes copies of the user's documentation for Task 1 and a CD ROM & diskette with an electronic copy of the user's documentation and an updated version of the "GRID 99" spreadsheet.

  19. [The High Precision Analysis Research of Multichannel BOTDR Scattering Spectral Information Based on the TTDF and CNS Algorithm].

    PubMed

    Zhang, Yan-jun; Liu, Wen-zhe; Fu, Xing-hu; Bi, Wei-hong

    2015-07-01

    Traditional BOTDR optical fiber sensing system uses single channel sensing fiber to measure the information features. Uncontrolled factors such as cross-sensitivity can lead to a lower scattering spectrum fitting precision and make the information analysis deflection get worse. Therefore, a BOTDR system for detecting the multichannel sensor information at the same time is proposed. Also it provides a scattering spectrum analysis method for multichannel Brillouin optical time-domain reflection (BOT-DR) sensing system in order to extract high precision spectrum feature. This method combines the three times data fusion (TTDF) and the cuckoo Newton search (CNS) algorithm. First, according to the rule of Dixon and Grubbs criteria, the method uses the ability of TTDF algorithm in data fusion to eliminate the influence of abnormal value and reduce the error signal. Second, it uses the Cuckoo Newton search algorithm to improve the spectrum fitting and enhance the accuracy of Brillouin scattering spectrum information analysis. We can obtain the global optimal solution by smart cuckoo search. By using the optimal solution as the initial value of Newton algorithm for local optimization, it can ensure the spectrum fitting precision. The information extraction at different linewidths is analyzed in temperature information scattering spectrum under the condition of linear weight ratio of 1:9. The variances of the multichannel data fusion is about 0.0030, the center frequency of scattering spectrum is 11.213 GHz and the temperature error is less than 0.15 K. Theoretical analysis and simulation results show that the algorithm can be used in multichannel distributed optical fiber sensing system based on Brillouin optical time domain reflection. It can improve the accuracy of multichannel sensing signals and the precision of Brillouin scattering spectrum analysis effectively. PMID:26717729

  20. 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

  1. Minimizing Interpolation Bias and Precision Error in In Vivo µCT-Based Measurements of Bone Structure and Dynamics.

    PubMed

    de Bakker, Chantal M J; Altman, Allison R; Li, Connie; Tribble, Mary Beth; Lott, Carina; Tseng, Wei-Ju; Liu, X Sherry

    2016-08-01

    In vivo µCT imaging allows for high-resolution, longitudinal evaluation of bone properties. Based on this technology, several recent studies have developed in vivo dynamic bone histomorphometry techniques that utilize registered µCT images to identify regions of bone formation and resorption, allowing for longitudinal assessment of bone remodeling. However, this analysis requires a direct voxel-by-voxel subtraction between image pairs, necessitating rotation of the images into the same coordinate system, which introduces interpolation errors. We developed a novel image transformation scheme, matched-angle transformation (MAT), whereby the interpolation errors are minimized by equally rotating both the follow-up and baseline images instead of the standard of rotating one image while the other remains fixed. This new method greatly reduced interpolation biases caused by the standard transformation. Additionally, our study evaluated the reproducibility and precision of bone remodeling measurements made via in vivo dynamic bone histomorphometry. Although bone remodeling measurements showed moderate baseline noise, precision was adequate to measure physiologically relevant changes in bone remodeling, and measurements had relatively good reproducibility, with intra-class correlation coefficients of 0.75-0.95. This indicates that, when used in conjunction with MAT, in vivo dynamic histomorphometry provides a reliable assessment of bone remodeling. PMID:26786342

  2. 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.

  3. Precise measurements of the properties of the B 1(5721)0 ,+ and B {2/*}(5747)0,+ states and observation of B + ,0 π - ,+ mass structures

    NASA Astrophysics Data System (ADS)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Anderson, J.; Andreassen, R.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Belogurov, S.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Brett, D.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casanova Mohr, R.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chiapolini, N.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Counts, I.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A. C.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dalseno, J.; David, P.; David, P. N. Y.; Davis, A.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Silva, W.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Domenico, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dreimanis, K.; Dujany, G.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Färber, C.; Farinelli, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fol, P.; Fontana, M.; Fontanelli, F.; Forty, R.; Francisco, O.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garofoli, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gastaldi, U.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Geraci, A.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianelle, A.; Gianí, S.; Gibson, V.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hampson, T.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Korolev, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kurek, K.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lowdon, P.; Lucchesi, D.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Machefert, F.; Machikhiliyan, I. V.; Maciuc, F.; Maev, O.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Märki, R.; Marks, J.; Martellotti, G.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; McSkelly, B.; Meadows, B.; Meier, F.; Meissner, M.; Merk, M.; Milanes, D. A.; Minard, M.-N.; Moggi, N.; Molina Rodriguez, J.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A.-B.; Mountain, R.; Muheim, F.; Müller, K.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Nicol, M.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Pal, B. K.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parkes, C.; Parkinson, C. J.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Pesen, E.; Petridis, K.; Petrolini, A.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Pistone, A.; Playfer, S.; Plo Casasus, M.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rakotomiaramanana, B.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruiz, H.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmidt, B.; Schneider, O.; Schopper, A.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sepp, I.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Silva Coutinho, R.; Simi, G.; Sirendi, M.; Skidmore, N.; Skillicorn, I.; Skwarnicki, T.; Smith, N. A.; Smith, E.; Smith, E.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Steinkamp, O.; Stenyakin, O.; Sterpka, F.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Stroili, R.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Teklishyn, M.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ubeda Garcia, M.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viana Barbosa, J. V.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Whitehead, M.; Wiedner, D.; Wilkinson, G.; Wilkinson, M.; Williams, M. P.; Williams, M.; Wilschut, H. W.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wyllie, K.; Xie, Y.; Xing, Z.; Xu, Z.; Yang, Z.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, W. C.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.

    2015-04-01

    Invariant mass distributions of B + π - and B 0 π + combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0 fb-1 of pp collision data, recorded by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B 1(5721)0,+ and B 2(5747)0,+ states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 5850-6000 MeV in both B + π - and B 0 π + combinations. The structures are consistent with the presence of four excited B mesons, labelled B J (5840)0,+ and B J (5960)0,+, whose masses and widths are obtained under different hypotheses for their quantum numbers. [Figure not available: see fulltext.

  4. Probabilistic methods for structural response analysis

    NASA Technical Reports Server (NTRS)

    Wu, Y.-T.; Burnside, O. H.; Cruse, T. A.

    1988-01-01

    This paper addresses current work to develop probabilistic structural analysis methods for integration with a specially developed probabilistic finite element code. The goal is to establish distribution functions for the structural responses of stochastic structures under uncertain loadings. Several probabilistic analysis methods are proposed covering efficient structural probabilistic analysis methods, correlated random variables, and response of linear system under stationary random loading.

  5. Precision analysis based on Cramer-Rao bound for 2D acoustics and electromagnetic inverse scattering

    NASA Astrophysics Data System (ADS)

    Diong, M. L.; Roueff, A.; Lasaygues, P.; Litman, A.

    2015-07-01

    The aim of the present article is to predict the expected precision quantitatively in inverse scattering when one tries to determine the intrinsic properties of a given target from its scattered field. To conduct such a study, we analyze the precision of contrast estimators with the Cramer-Rao bound (CRB) when the target is homogeneous, infinitely-long and with a circular cross-section and with an additive complex circular gaussian noise at the receivers. An unified framework is derived to handle acoustic or electromagnetic imaging configurations equally. Numerical tests enable to quantitatively appraise the variations of the CRB with respect to the considered physical situation parameters: transmission/reflexion, antennas arrangement, weak/strong scatterers, noise level and source frequency. These analyzes are performed with respect to the real and imaginary parts of the contrast.

  6. 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.

  7. 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.

  8. Precision Analysis Based on Complicated Error Simulation for the Orbit Determination with the Space Tracking Ship

    NASA Astrophysics Data System (ADS)

    Lei, YANG; Caifa, GUO; Zhengxu, DAI; Xiaoyong, LI; Shaolin, WANG

    2016-02-01

    The space tracking ship is a moving platform in the TT&C network. The orbit determination precision of the ship plays a key role in the TT&C mission. Based on the measuring data obtained by the ship-borne equipments, the paper presents the mathematic models of the complicated error from the space tracking ship, which can separate the random error and the correction residual error with secondary low frequency from the complicated error. An error simulation algorithm is proposed to analyze the orbit determination precision based on the two set of the different equipments. With this algorithm, a group of complicated error can be simulated from a measured sample. The simulated error groups can meet the requirements of sufficient complicated error for the equipment tests before the mission execution, which is helpful to the practical application.

  9. 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.

  10. 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.