Linear analysis using secants for materials with temperature dependent nonlinear elastic modulus and thermal expansion properties

NASA Astrophysics Data System (ADS)

Pepi, John W.

2017-08-01

Thermally induced stress is readily calculated for linear elastic material properties using Hooke's law in which, for situations where expansion is constrained, stress is proportional to the product of the material elastic modulus and its thermal strain. When material behavior is nonlinear, one needs to make use of nonlinear theory. However, we can avoid that complexity in some situations. For situations in which both elastic modulus and coefficient of thermal expansion vary with temperature, solutions can be formulated using secant properties. A theoretical approach is thus presented to calculate stresses for nonlinear, neo-Hookean, materials. This is important for high acuity optical systems undergoing large temperature extremes.

Tunable Liquid Gradient Refractive Index (L-GRIN) lens with two degrees of freedom.

PubMed

Mao, Xiaole; Lin, Sz-Chin Steven; Lapsley, Michael Ian; Shi, Jinjie; Juluri, Bala Krishna; Huang, Tony Jun

2009-07-21

We report a tunable optofluidic microlens configuration named the Liquid Gradient Refractive Index (L-GRIN) lens for focusing light within a microfluidic device. The focusing of light was achieved through the gradient refractive index (GRIN) within the liquid medium, rather than via curved refractive lens surfaces. The diffusion of solute (CaCl(2)) between side-by-side co-injected microfluidic laminar flows was utilized to establish a hyperbolic secant (HS) refractive index profile to focus light. Tailoring the refractive index profile by adjusting the flow conditions enables not only tuning of the focal distance (translation mode), but also shifting of the output light direction (swing mode), a second degree of freedom that to our knowledge has yet to be accomplished for in-plane tunable microlenses. Advantages of the L-GRIN lens also include a low fluid consumption rate, competitive focusing performance, and high compatibility with existing microfluidic devices. This work provides a new strategy for developing integrative tunable microlenses for a variety of lab-on-a-chip applications.

Storage and retrieval of time-entangled soliton trains in a three-level atom system coupled to an optical cavity

NASA Astrophysics Data System (ADS)

Welakuh, Davis D. M.; Dikandé, Alain M.

2017-11-01

The storage and subsequent retrieval of coherent pulse trains in the quantum memory (i.e. cavity-dark state) of three-level Λ atoms, are considered for an optical medium in which adiabatic photon transfer occurs under the condition of quantum impedance matching. The underlying mechanism is based on intracavity Electromagnetically-Induced Transparency, by which properties of a cavity filled with three-level Λ-type atoms are manipulated by an external control field. Under the impedance matching condition, we derive analytic expressions that suggest a complete transfer of an input field into the cavity-dark state by varying the mixing angle in a specific way, and its subsequent retrieval at a desired time. We illustrate the scheme by demonstrating the complete transfer and retrieval of a Gaussian, a single hyperbolic-secant and a periodic train of time-entangled hyperbolic-secant input photon pulses in the atom-cavity system. For the time-entangled hyperbolic-secant input field, a total controllability of the periodic evolution of the dark state population is made possible by changing the Rabi frequency of the classical driving field, thus allowing to alternately store and retrieve high-intensity photons from the optically dense Electromagnetically-Induced transparent medium. Such multiplexed photon states, which are expected to allow sharing quantum information among many users, are currently of very high demand for applications in long-distance and multiplexed quantum communication.

MHOST: An efficient finite element program for inelastic analysis of solids and structures

NASA Technical Reports Server (NTRS)

Nakazawa, S.

1988-01-01

An efficient finite element program for 3-D inelastic analysis of gas turbine hot section components was constructed and validated. A novel mixed iterative solution strategy is derived from the augmented Hu-Washizu variational principle in order to nodally interpolate coordinates, displacements, deformation, strains, stresses and material properties. A series of increasingly sophisticated material models incorporated in MHOST include elasticity, secant plasticity, infinitesimal and finite deformation plasticity, creep and unified viscoplastic constitutive model proposed by Walker. A library of high performance elements is built into this computer program utilizing the concepts of selective reduced integrations and independent strain interpolations. A family of efficient solution algorithms is implemented in MHOST for linear and nonlinear equation solution including the classical Newton-Raphson, modified, quasi and secant Newton methods with optional line search and the conjugate gradient method.

Effects of mode profile on tunneling and traversal of ultracold atoms through vacuum-induced potentials

NASA Astrophysics Data System (ADS)

Badshah, Fazal; Irfan, Muhammad; Qamar, Sajid; Qamar, Shahid

2016-04-01

We consider the resonant interaction of an ultracold two-level atom with an electromagnetic field inside a high-Q micromaser cavity. In particular, we study the tunneling and traversal of ultracold atoms through vacuum-induced potentials for secant hyperbolic square and sinusoidal cavity mode functions. The phase time which may be considered as an appropriate measure of the time required for the atoms to cross the cavity, significantly modifies with the change of cavity mode profile. For example, switching between the sub and superclassical behaviors in phase time can occur due to the mode function. Similarly, negative phase time appears for the transmission of the two-level atoms in both excited and ground states for secant hyperbolic square mode function which is in contrast to the mesa mode case.

Scrape-off layer reflectometer for Alcator C-Mod.

PubMed

Lau, Cornwall; Hanson, Greg; Wilgen, John; Lin, Yijun; Wukitch, Steve

2010-10-01

A swept-frequency X-mode reflectometer is being built for Alcator C-Mod to measure the scrape-off layer density profiles at the top, middle, and bottom locations in front of both the new lower hybrid launcher and the new ion cyclotron range of frequencies antenna. The system is planned to operate between 100 and 146 GHz at sweep rates from 10 μs to 1 ms, and will cover a density range of approximately 10(16)-10(20) m(-3) at B(0)=5-5.4 T. To minimize the effects of density fluctuations, both differential phase and full phase reflectometry will be employed. Design, test data, and calibration results of this electronics system will be discussed. To reduce attenuation losses, tallguide (TE(01)) will be used for most of the transmission line system. Simulations of high mode conversion in tallguide components, such as e-plane hyperbolic secant radius of curvature bends, tapers, and horn antennas will be shown. Experimental measurements of the total attenuation losses of these components in the lower hybrid waveguide run will also be presented.

Navier-Stokes predictions of pitch damping for axisymmetric shell using steady coning motion

NASA Technical Reports Server (NTRS)

Weinacht, Paul; Sturek, Walter B.; Schiff, Lewis B.

1991-01-01

Previous theoretical investigations have proposed that the side force and moment acting on a body of revolution in steady coning motion could be related to the pitch-damping force and moment. In the current research effort, this approach is applied to produce predictions of the pitch damping for axisymmetric shell. The flow fields about these projectiles undergoing steady coning motion are successfully computed using a parabolized Navier-Stokes computational approach which makes use of a rotating coordinate frame. The governing equations are modified to include the centrifugal and Coriolis force terms due to the rotating coordinate frame. From the computed flow field, the side moments due to coning motion, spinning motion, and combined spinning and coning motion are used to determine the pitch-damping coefficients. Computations are performed for two generic shell configurations, a secant-ogive-cylinder and a secant-ogive-cylinder-boattail.

Anisotropy of demineralized bone matrix under compressive load.

PubMed

Trębacz, Hanna; Zdunek, Artur

2011-01-01

Two groups of cubic specimens from diaphysis of bovine femur, intact and completely demineralized, were axially compressed. One half of the samples from each group were loaded along the axis of the femur (L) and the other - perpendicularly (T). Intact samples were characterized in terms of elastic modulus; for demineralized samples secant modulus of elasticity was calculated. During compression an acoustic emission (AE) signal was recorded and AE events and energy were analyzed. Samples of intact bone did not reveal any anisotropy under compression at the stress of 80 MPa. However, AE signal indicated an initiation of failure in samples loaded in T direction. Demineralized samples were anisotropic under compression. Both secant modulus of elasticity and AE parameters were significantly higher in T direction than in L direction, which is attributed to shifting and separation of lamellae of collagen fibrils and lamellae in bone matrix.

Preconditioning strategies for nonlinear conjugate gradient methods, based on quasi-Newton updates

NASA Astrophysics Data System (ADS)

Andrea, Caliciotti; Giovanni, Fasano; Massimo, Roma

2016-10-01

This paper reports two proposals of possible preconditioners for the Nonlinear Conjugate Gradient (NCG) method, in large scale unconstrained optimization. On one hand, the common idea of our preconditioners is inspired to L-BFGS quasi-Newton updates, on the other hand we aim at explicitly approximating in some sense the inverse of the Hessian matrix. Since we deal with large scale optimization problems, we propose matrix-free approaches where the preconditioners are built using symmetric low-rank updating formulae. Our distinctive new contributions rely on using information on the objective function collected as by-product of the NCG, at previous iterations. Broadly speaking, our first approach exploits the secant equation, in order to impose interpolation conditions on the objective function. In the second proposal we adopt and ad hoc modified-secant approach, in order to possibly guarantee some additional theoretical properties.

Fast secant methods for the iterative solution of large nonsymmetric linear systems

NASA Technical Reports Server (NTRS)

Deuflhard, Peter; Freund, Roland; Walter, Artur

1990-01-01

A family of secant methods based on general rank-1 updates was revisited in view of the construction of iterative solvers for large non-Hermitian linear systems. As it turns out, both Broyden's good and bad update techniques play a special role, but should be associated with two different line search principles. For Broyden's bad update technique, a minimum residual principle is natural, thus making it theoretically comparable with a series of well known algorithms like GMRES. Broyden's good update technique, however, is shown to be naturally linked with a minimum next correction principle, which asymptotically mimics a minimum error principle. The two minimization principles differ significantly for sufficiently large system dimension. Numerical experiments on discretized partial differential equations of convection diffusion type in 2-D with integral layers give a first impression of the possible power of the derived good Broyden variant.

Model correlation and damage location for large space truss structures: Secant method development and evaluation

NASA Technical Reports Server (NTRS)

Smith, Suzanne Weaver; Beattie, Christopher A.

1991-01-01

On-orbit testing of a large space structure will be required to complete the certification of any mathematical model for the structure dynamic response. The process of establishing a mathematical model that matches measured structure response is referred to as model correlation. Most model correlation approaches have an identification technique to determine structural characteristics from the measurements of the structure response. This problem is approached with one particular class of identification techniques - matrix adjustment methods - which use measured data to produce an optimal update of the structure property matrix, often the stiffness matrix. New methods were developed for identification to handle problems of the size and complexity expected for large space structures. Further development and refinement of these secant-method identification algorithms were undertaken. Also, evaluation of these techniques is an approach for model correlation and damage location was initiated.

Quasi-Newton parallel geometry optimization methods

NASA Astrophysics Data System (ADS)

Burger, Steven K.; Ayers, Paul W.

2010-07-01

Algorithms for parallel unconstrained minimization of molecular systems are examined. The overall framework of minimization is the same except for the choice of directions for updating the quasi-Newton Hessian. Ideally these directions are chosen so the updated Hessian gives steps that are same as using the Newton method. Three approaches to determine the directions for updating are presented: the straightforward approach of simply cycling through the Cartesian unit vectors (finite difference), a concurrent set of minimizations, and the Lanczos method. We show the importance of using preconditioning and a multiple secant update in these approaches. For the Lanczos algorithm, an initial set of directions is required to start the method, and a number of possibilities are explored. To test the methods we used the standard 50-dimensional analytic Rosenbrock function. Results are also reported for the histidine dipeptide, the isoleucine tripeptide, and cyclic adenosine monophosphate. All of these systems show a significant speed-up with the number of processors up to about eight processors.

Postinjury biomechanics of Achilles tendon vary by sex and hormone status

PubMed Central

Fryhofer, George W.; Freedman, Benjamin R.; Hillin, Cody D.; Salka, Nabeel S.; Pardes, Adam M.; Weiss, Stephanie N.; Farber, Daniel C.

2016-01-01

Achilles tendon ruptures are common injuries. Sex differences are present in mechanical properties of uninjured Achilles tendon, but it remains unknown if these differences extend to tendon healing. We hypothesized that ovariectomized females (OVX) and males would exhibit inferior postinjury tendon properties compared with females. Male, female, and OVX Sprague-Dawley rats (n = 32/group) underwent acclimation and treadmill training before blunt transection of the Achilles tendon midsubstance. Injured hindlimbs were immobilized for 1 wk, followed by gradual return to activity and assessment of active and passive hindlimb function. Animals were euthanized at 3 or 6 wk postinjury to assess tendon structure, mechanics, and composition. Passive ankle stiffness and range of motion were superior in females at 3 wk; however, by 6 wk, passive and active function were similar in males and females but remained inferior in OVX. At 6 wk, female tendons had greater normalized secant modulus, viscoelastic behavior, and laxity compared with males. Normalized secant modulus, cross-sectional area and tendon glycosaminoglycan composition were inferior in OVX compared with females at 6 wk. Total fatigue cycles until tendon failure were similar among groups. Postinjury muscle fiber size was better preserved in females compared with males, and females had greater collagen III at the tendon injury site compared with males at 6 wk. Despite male and female Achilles tendons withstanding similar durations of fatigue loading, early passive hindlimb function and tendon mechanical properties, including secant modulus, suggest superior healing in females. Ovarian hormone loss was associated with inferior Achilles tendon healing. PMID:27633741

Alternative Proofs for Inequalities of Some Trigonometric Functions

ERIC Educational Resources Information Center

Guo, Bai-Ni; Qi, Feng

2008-01-01

By using an identity relating to Bernoulli's numbers and power series expansions of cotangent function and logarithms of functions involving sine function, cosine function and tangent function, four inequalities involving cotangent function, sine function, secant function and tangent function are established.

R&D 100, 2016: T-Quake – Quantum-Mechanical Transmitter/Receiver Microchip

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tauke-Pedretti, Anna; Camacho, Ryan; Thayer, Gayle

2016-11-07

Applying advanced microfabrication techniques and innovative microdesign, the Sandia Enabled Communications and Authentication Network (SECANT) team has designed and produced photonic microchips capable of sending, receiving, and processing quantum signals for applications in cyber and physical security.

R&D 100, 2016: T-Quake – Quantum-Mechanical Transmitter/Receiver Microchip

ScienceCinema

Tauke-Pedretti, Anna; Camacho, Ryan; Thayer, Gayle

2018-06-13

Applying advanced microfabrication techniques and innovative microdesign, the Sandia Enabled Communications and Authentication Network (SECANT) team has designed and produced photonic microchips capable of sending, receiving, and processing quantum signals for applications in cyber and physical security.

Tunable two-dimensional liquid gradient refractive index (L-GRIN) lens for variable light focusing.

PubMed

Huang, Hua; Mao, Xiaole; Lin, Sz-Chin Steven; Kiraly, Brian; Huang, Yiping; Huang, Tony Jun

2010-09-21

We report a two-dimensional (2D) tunable liquid gradient refractive index (L-GRIN) lens for variable focusing of light in the out-of-plane direction. This lens focuses a light beam through a liquid medium with a 2D hyperbolic secant (HS) refractive index gradient. The refractive index gradient is established in a microfluidic chamber through the diffusion between two fluids with different refractive indices, i.e. CaCl(2) solution and deionized (DI) water. The 2D HS refractive index profile and subsequently the focal length of the L-GRIN lens can be tuned by changing the ratio of the flow rates of the CaCl(2) solution and DI water. The focusing effect is experimentally characterized through side-view and top-view image analysis, and the experimental data match well with the results from ray-tracing optical simulations. Advantages of the 2D L-GRIN lens include simple device fabrication procedure, low fluid consumption rate, convenient lens-tuning mechanism, and compatibility with existing microfluidic devices. We expect that with further optimizations, this 2D L-GRIN lens can be used in many optics-based lab-on-a-chip applications.

Parameters Identification of Interface Friction Model for Ceramic Matrix Composites Based on Stress-Strain Response

NASA Astrophysics Data System (ADS)

Han, Xiao; Gao, Xiguang; Song, Yingdong

2017-10-01

An approach to identify parameters of interface friction model for Ceramic Matrix composites based on stress-strain response was developed. The stress distribution of fibers in the interface slip region and intact region of the damaged composite was determined by adopting the interface friction model. The relation between maximum strain, secant moduli of hysteresis loop and interface shear stress, interface de-bonding stress was established respectively with the method of symbolic-graphic combination. By comparing the experimental strain, secant moduli of hysteresis loop with computation values, the interface shear stress and interface de-bonding stress corresponding to first cycle were identified. Substituting the identification of parameters into interface friction model, the stress-strain curves were predicted and the predicted results fit experiments well. Besides, the influence of number of data points on identifying the value of interface parameters was discussed. And the approach was compared with the method based on the area of hysteresis loop.

Constructing and Deriving Reciprocal Trigonometric Relations: A Functional Analytic Approach

ERIC Educational Resources Information Center

Ninness, Chris; Dixon, Mark; Barnes-Holmes, Dermot; Rehfeldt, Ruth Anne; Rumph, Robin; McCuller, Glen; Holland, James; Smith, Ronald; Ninness, Sharon K.; McGinty, Jennifer

2009-01-01

Participants were pretrained and tested on mutually entailed trigonometric relations and combinatorially entailed relations as they pertained to positive and negative forms of sine, cosine, secant, and cosecant. Experiment 1 focused on training and testing transformations of these mathematical functions in terms of amplitude and frequency followed…

Tensile and pack compressive tests of some sheets of aluminum alloy, 1025 carbon steel, and chromium-nickel steel

NASA Technical Reports Server (NTRS)

Atchison, C S; Miller, James A

1942-01-01

Tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves are given for longitudinal and transverse specimens of 17S-T, 24S-T, and 24S-RT aluminum-alloy sheet in thicknesses from 0.032 to 0.081 inch, 1025 carbon steel sheet in thicknesses of 0.054 and 0.120 inch, and chromium-nickel steel sheet in thicknesses form 0.020 to 0.0275 inch. Significant differences were found between the tensile and the compressive stress-strain curves, and also the corresponding corollary curves; similarly, differences were found between the curves for the longitudinal and transverse directions. These differences are of particular importance in considering the compressive strength of aircraft structures made of thin sheet. They are explored further for the case of compression by giving tangent modulus-stress curves in longitudinal and transverse compression and dimensionless curves of the ratio of tangent modulus to Young's modulus and of the ratio of reduced modulus for a rectangular section to Young's modulus, both plotted against the ratio of stress to secant yield strength.

An Energy-Equivalent d+/d− Damage Model with Enhanced Microcrack Closure-Reopening Capabilities for Cohesive-Frictional Materials

PubMed Central

Cervera, Miguel; Tesei, Claudia

2017-01-01

In this paper, an energy-equivalent orthotropic d+/d− damage model for cohesive-frictional materials is formulated. Two essential mechanical features are addressed, the damage-induced anisotropy and the microcrack closure-reopening (MCR) effects, in order to provide an enhancement of the original d+/d− model proposed by Faria et al. 1998, while keeping its high algorithmic efficiency unaltered. First, in order to ensure the symmetry and positive definiteness of the secant operator, the new formulation is developed in an energy-equivalence framework. This proves thermodynamic consistency and allows one to describe a fundamental feature of the orthotropic damage models, i.e., the reduction of the Poisson’s ratio throughout the damage process. Secondly, a “multidirectional” damage procedure is presented to extend the MCR capabilities of the original model. The fundamental aspects of this approach, devised for generic cyclic conditions, lie in maintaining only two scalar damage variables in the constitutive law, while preserving memory of the degradation directionality. The enhanced unilateral capabilities are explored with reference to the problem of a panel subjected to in-plane cyclic shear, with or without vertical pre-compression; depending on the ratio between shear and pre-compression, an absent, a partial or a complete stiffness recovery is simulated with the new multidirectional procedure. PMID:28772793

Combining harmonic generation and laser chirping to achieve high spectral density in Compton sources

DOE PAGES

Terzić, Balša; Reeves, Cody; Krafft, Geoffrey A.

2016-04-25

Recently various laser-chirping schemes have been investigated with the goal of reducing or eliminating ponderomotive line broadening in Compton or Thomson scattering occurring at high laser intensities. Moreover, as a next level of detail in the spectrum calculations, we have calculated the line smoothing and broadening expected due to incident beam energy spread within a one-dimensional plane wave model for the incident laser pulse, both for compensated (chirped) and unchirped cases. The scattered compensated distributions are treatable analytically within three models for the envelope of the incident laser pulses: Gaussian, Lorentzian, or hyperbolic secant. We use the new results tomore » demonstrate that the laser chirping in Compton sources at high laser intensities: (i) enables the use of higher order harmonics, thereby reducing the required electron beam energies; and (ii) increases the photon yield in a small frequency band beyond that possible with the fundamental without chirping. We found that this combination of chirping and higher harmonics can lead to substantial savings in the design, construction and operational costs of the new Compton sources. This is of particular importance to the widely popular laser-plasma accelerator based Compton sources, as the improvement in their beam quality enters the regime where chirping is most effective.« less

A Finite Element Study on Crack Tip Deformation.

DTIC Science & Technology

1976-08-01

REPOPINUMDER • TNOR(.) CONTRACT OR GRANT NUMSER(.) ______ ~~~ ~~~ /I. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMEN T. PROJECT . TASKJ AREA ...that the bulk of the strain measurements agree well with the results of the plane stress calculations except in the small area close to the crack tip...that the bulk of the strain measurements agree veil with the results of the plane stress calcula- tions except in the small area cloae to the crack

Utilizing a Coupled Nonlinear Schrödinger Model to Solve the Linear Modal Problem for Stratified Flows

NASA Astrophysics Data System (ADS)

Liu, Tianyang; Chan, Hiu Ning; Grimshaw, Roger; Chow, Kwok Wing

2017-11-01

The spatial structure of small disturbances in stratified flows without background shear, usually named the `Taylor-Goldstein equation', is studied by employing the Boussinesq approximation (variation in density ignored except in the buoyancy). Analytical solutions are derived for special wavenumbers when the Brunt-Väisälä frequency is quadratic in hyperbolic secant, by comparison with coupled systems of nonlinear Schrödinger equations intensively studied in the literature. Cases of coupled Schrödinger equations with four, five and six components are utilized as concrete examples. Dispersion curves for arbitrary wavenumbers are obtained numerically. The computations of the group velocity, second harmonic, induced mean flow, and the second derivative of the angular frequency can all be facilitated by these exact linear eigenfunctions of the Taylor-Goldstein equation in terms of hyperbolic function, leading to a cubic Schrödinger equation for the evolution of a wavepacket. The occurrence of internal rogue waves can be predicted if the dispersion and cubic nonlinearity terms of the Schrödinger equations are of the same sign. Partial financial support has been provided by the Research Grants Council contract HKU 17200815.

Using Technology to Unify Geometric Theorems about the Power of a Point

ERIC Educational Resources Information Center

Contreras, Jose N.

2011-01-01

In this article, I describe a classroom investigation in which a group of prospective secondary mathematics teachers discovered theorems related to the power of a point using "The Geometer's Sketchpad" (GSP). The power of a point is defines as follows: Let "P" be a fixed point coplanar with a circle. If line "PA" is a secant line that intersects…

Results of Laboratory Tests of the Filtration Characteristics of Clay-Cement Concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sol’skii, S. V., E-mail: solskiysv@vniig.ru; Lopatina, M. G., E-mail: LoptainaMG@vniig.ru; Legina, E. E.

Laboratory studies of the filtration characteristics of clay-cement concrete materials for constructing filtering diaphragms of earth dams by the method of secant piles are reported. Areas for further study aimed at improving the quality of construction, increasing operational safety, and developing a standards base for the design, construction, and operation of these systems are discussed.

Evolution of Hyperbolic-Secant Pulses Towards Cross-Phase Modulation Induced Optical Wave Breaking and Soliton or Soliton Trains Generation in Quintic Nonlinear Fibers

NASA Astrophysics Data System (ADS)

Zhong, Xian-Qiong; Zhang, Xiao-Xia; Du, Xian-Tong; Liu, Yong; Cheng, Ke

2015-10-01

The approximate analytical frequency chirps and the critical distances for cross-phase modulation induced optical wave breaking (OWB) of the initial hyperbolic-secant optical pulses propagating in optical fibers with quintic nonlinearity (QN) are presented. The pulse evolutions in terms of the frequency chirps, shapes and spectra are numerically calculated in the normal dispersion regime. The results reveal that, depending on different QN parameters, the traditional OWB or soliton or soliton pulse trains may occur. The approximate analytical critical distances are found to be in good agreement with the numerical ones only for the traditional OWB whereas the approximate analytical frequency chirps accords well with the numerical ones at the initial evolution stages of the pulses. Supported by the Postdoctoral Fund of China under Grant No. 2011M501402, the Key Project of Chinese Ministry of Education under Grant No. 210186, the Major Project of Natural Science Supported by the Educational Department of Sichuan Province under Grant No. 13ZA0081, the Key Project of National Natural Science Foundation of China under Grant No 61435010, and the National Natural Science Foundation of China under Grant No. 61275039

Patient-specific positioning guides for total knee arthroplasty: no significant difference between final component alignment and pre-operative digital plan except for tibial rotation.

PubMed

Boonen, Bert; Schotanus, Martijn G M; Kerens, Bart; Hulsmans, Frans-Jan; Tuinebreijer, Wim E; Kort, Nanne P

2017-09-01

To assess whether there is a significant difference between the alignment of the individual femoral and tibial components (in the frontal, sagittal and horizontal planes) as calculated pre-operatively (digital plan) and the actually achieved alignment in vivo obtained with the use of patient-specific positioning guides (PSPGs) for TKA. It was hypothesised that there would be no difference between post-op implant position and pre-op digital plan. Twenty-six patients were included in this non-inferiority trial. Software permitted matching of the pre-operative MRI scan (and therefore calculated prosthesis position) to a pre-operative CT scan and then to a post-operative full-leg CT scan to determine deviations from pre-op planning in all three anatomical planes. For the femoral component, mean absolute deviations from planning were 1.8° (SD 1.3), 2.5° (SD 1.6) and 1.6° (SD 1.4) in the frontal, sagittal and transverse planes, respectively. For the tibial component, mean absolute deviations from planning were 1.7° (SD 1.2), 1.7° (SD 1.5) and 3.2° (SD 3.6) in the frontal, sagittal and transverse planes, respectively. Absolute mean deviation from planned mechanical axis was 1.9°. The a priori specified null hypothesis for equivalence testing: the difference from planning is >3 or <-3 was rejected for all comparisons except for the tibial transverse plane. PSPG was able to adequately reproduce the pre-op plan in all planes, except for the tibial rotation in the transverse plane. Possible explanations for outliers are discussed and highlight the importance for adequate training surgeons before they start using PSPG in their day-by-day practise. Prospective cohort study, Level II.

Analysis of the Localization of Michelson Interferometer Fringes Using Fourier Optics and Temporal Coherence

ERIC Educational Resources Information Center

Narayanamurthy, C. S.

2009-01-01

Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in "Principles of Optics" by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer…

On equivalent characterizations of convexity of functions

NASA Astrophysics Data System (ADS)

Gkioulekas, Eleftherios

2013-04-01

A detailed development of the theory of convex functions, not often found in complete form in most textbooks, is given. We adopt the strict secant line definition as the definitive definition of convexity. We then show that for differentiable functions, this definition becomes logically equivalent with the first derivative monotonicity definition and the tangent line definition. Consequently, for differentiable functions, all three characterizations are logically equivalent.

Wedge-shaped slice-selective adiabatic inversion pulse for controlling temporal width of bolus in pulsed arterial spin labeling

PubMed Central

Guo, Jia; Buxton, Richard B.; Wong, Eric C.

2015-01-01

Purpose In pulsed arterial spin labeling (PASL) methods, arterial blood is labeled via inverting a slab with uniform thickness, resulting in different temporal widths of boluses in vessels with different flow velocities. This limits the temporal resolution and signal-to-noise ratio (SNR) efficiency gains in PASL-based methods intended for high temporal resolution and SNR efficiency, such as Turbo-ASL and Turbo-QUASAR. Theory and Methods A novel wedge-shaped (WS) adiabatic inversion pulse is developed by adding in-plane gradient pulses to a slice-selective (SS) adiabatic inversion pulse to linearly modulate the inversion thicknesses at different locations while maintaining the adiabatic properties of the original pulse. A hyperbolic secant (HS) based WS inversion pulse was implemented. Its performance was tested in simulations, phantom and human experiments, and compared to an SS HS inversion pulse. Results Compared to the SS inversion pulse, the WS inversion pulse is capable of inducing different inversion thicknesses at different locations. It can be adjusted to generate a uniform temporal width of boluses in arteries at locations with different flow velocities. Conclusion The WS inversion pulse can be used to control the temporal widths of labeled boluses in PASL experiments. This should benefit PASL experiments by maximizing labeling duty cycle, and improving temporal resolution and SNR efficiency. PMID:26451521

Confinement Effect on Material Properties of RC Beams Under Flexure

NASA Astrophysics Data System (ADS)

Kulkarni, Sumant; Shiyekar, Mukund Ramchandra; Shiyekar, Sandip Mukund

2017-12-01

In structural analysis, especially in indeterminate structures, it becomes essential to know the material and geometrical properties of members. The codal provisions recommend elastic properties of concrete and steel and these are fairly accurate enough. The stress-strain curve for concrete cylinder or a cube specimen is plotted. The slope of this curve is modulus of elasticity of plain concrete. Another method of determining modulus of elasticity of concrete is by flexural test of a beam specimen. The modulus of elasticity most commonly used for concrete is secant modulus. The modulus of elasticity of steel is obtained by performing a tension test of steel bar. While performing analysis by any software for high rise building, cross area of plain concrete is taken into consideration whereas effects of reinforcement bars and concrete confined by stirrups are neglected. Present aim of study is to determine elastic properties of reinforced cement concrete beam. Two important stiffness properties such as AE and EI play important role in analysis of high rise RCC building idealized as plane frame. The experimental program consists of testing of beams (model size 150 × 150 × 700 mm) with percentage of reinforcement varying from 0.54 to 1.63% which commensurate with existing Codal provisions of IS:456-2000 for flexural member. The effect of confinement is considered in this study. The experimental results are verified by using 3D finite element techniques.

Study of the quaternary Na+, K+//F-, Br-, NO 3 - reciprocal system using an innovative methodology

NASA Astrophysics Data System (ADS)

Morgunova, O. E.; Ukhanov, A. S.; Katasonova, E. A.; Trunin, A. S.; Surinskii, K. D.

2016-08-01

The topological structure of the quaternary Na+, K+//F-, Br-, NO 3 - system is studied using a computer-assisted research system. A tree of phases is constructed, and the eutectic characteristics of the secant triangle NaNO3-KBr-NaF, (equiv. %) 84.6 NaNO3-9.1 KBr-6.3 NaF, at 255.3°C are determined.

Aerodynamics of Supersonic Lifting Bodies

DTIC Science & Technology

1981-02-01

Correction Velocity Ratio, y = 1.4 .. ......... . . . . 38 9 Perturbation Pressure Coefficient on the Body Surface .... 41 10 Pressure Coefficient on...Secant Method and Exper.1ent ... ....... 119 40 Geometrica . :onfinmration anl 7ro)r;1Tnate Systens ....... 125 41 1pheri. •a. 1-rinites...due to pitching p contribution due to plunging 8 shock wave w wedge z contribution due to pitching about Ln 0 free stream Superscripts (c) correction

Eliminating electromechanical instability in dielectric elastomers by employing pre-stretch

NASA Astrophysics Data System (ADS)

Jiang, Liang; Betts, Anthony; Kennedy, David; Jerrams, Stephen

2016-07-01

Electromechanical instability (EMI) is one of most common failure modes for dielectric elastomers (DEs). It has been reported that pre-stretching a DE sample can suppress EMI due to strain stiffening taking place for larger strains and a higher elastic modulus are achieved at high stretch ratios when a voltage is applied to the material. In this work, the influence of equi-biaxial stretch on DE secant modulus was studied using VHB 4910 and silicone rubber (SR) composites containing barium titanate (BaTiO3, BT) particles and also dopamine coated BT (DP-BT) particles. The investigation of equi-biaxial deformation and EMI failure for VHB 4910 was undertaken by introducing a voltage-stretch function. The results showed that EMI was suppressed by equi-biaxial pre-stretch for all the DEs fabricated and tested. The stiffening properties of the DE materials were also studied with respect to the secant modulus. Furthermore, a voltage-induced strain of above 200% was achieved for the polyacrylate film by applying a pre-stretch ratio of 2.0 without EMI occurring. However, a maximum voltage-induced strain in the polyacrylate film of 78% was obtained by the SR/20 wt% DP-BT composite for a lower applied pre-stretch ratio of 1.6 and again EMI was eliminated.

Numerical simulation of elasto-plastic deformation of composites: evolution of stress microfields and implications for homogenization models

NASA Astrophysics Data System (ADS)

González, C.; Segurado, J.; LLorca, J.

2004-07-01

The deformation of a composite made up of a random and homogeneous dispersion of elastic spheres in an elasto-plastic matrix was simulated by the finite element analysis of three-dimensional multiparticle cubic cells with periodic boundary conditions. "Exact" results (to a few percent) in tension and shear were determined by averaging 12 stress-strain curves obtained from cells containing 30 spheres, and they were compared with the predictions of secant homogenization models. In addition, the numerical simulations supplied detailed information of the stress microfields, which was used to ascertain the accuracy and the limitations of the homogenization models to include the nonlinear deformation of the matrix. It was found that secant approximations based on the volume-averaged second-order moment of the matrix stress tensor, combined with a highly accurate linear homogenization model, provided excellent predictions of the composite response when the matrix strain hardening rate was high. This was not the case, however, in composites which exhibited marked plastic strain localization in the matrix. The analysis of the evolution of the matrix stresses revealed that better predictions of the composite behavior can be obtained with new homogenization models which capture the essential differences in the stress carried by the elastic and plastic regions in the matrix at the onset of plastic deformation.

Ferrofluid lubrication of circular squeeze film bearings controlled by variable magnetic field with rotations of the discs, porosity and slip velocity

NASA Astrophysics Data System (ADS)

Shah, Rajesh C.; Shah, Rajiv B.

2017-12-01

Based on the Shliomis ferrofluid flow model (SFFM) and continuity equation for the film as well as porous region, modified Reynolds equation for lubrication of circular squeeze film bearings is derived by considering the effects of oblique radially variable magnetic field (VMF), slip velocity at the film-porous interface and rotations of both the discs. The squeeze film bearings are made up of circular porous upper disc of different shapes (exponential, secant, mirror image of secant and parallel) and circular impermeable flat lower disc. The validity of Darcy's Law is assumed in the porous region. The SFFM is important because it includes the effects of rotations of the carrier liquid as well as magnetic particles. The VMF is used because of its advantage of generating maximum field at the required active contact area of the bearing design system. Also, the effect of porosity is included because of its advantageous property of self-lubrication. Using Reynolds equation, general form of pressure equation is derived and expression for dimensionless load-carrying capacity is obtained. Using this expression, results for different bearing design systems (due to different shapes of the upper disc) are computed and compared for variation of different parameters.

The Pinhole/Occulter Facility

NASA Technical Reports Server (NTRS)

Tandberg-Hanssen, E. A. (Editor); Hudson, H. S. (Editor); Dabbs, J. R. (Editor); Baity, W. A. (Editor)

1983-01-01

Scientific objectives and requirements are discussed for solar X-ray observations, coronagraph observations, studies of coronal particle acceleration, and cosmic X-ray observations. Improved sensitivity and resolution can be provided for these studies using the pinhole/occulter facility which consists of a self-deployed boom of 50 m length separating an occulter plane from a detector plane. The X-ray detectors and coronagraphic optics mounted on the detector plane are analogous to the focal plane instrumentation of an ordinary telescope except that they use the occulter only for providing a shadow pattern. The occulter plane is passive and has no electrical interface with the rest of the facility.

Picard Trajectory Approximation Iteration for Efficient Orbit Propagation

DTIC Science & Technology

2015-07-21

Eqn (8)) for an iterative ap- proximation of eccentric anomaly, and is transformed back to . The Lambert/ Kepler time – eccentric anomaly relationship...of Kepler motion based on spinor regulari- zation, Journal fur die Reine und Angewandt Mathematik 218, 204-219, 1965. [3] Levi-Civita T., Sur la...transformed back to  , ,x y z . The Lambert/ Kepler time – eccentric anomaly relationship is iterated by a Newton/Secant method to converge on the

On universal knot polynomials

NASA Astrophysics Data System (ADS)

Mironov, A.; Mkrtchyan, R.; Morozov, A.

2016-02-01

We present a universal knot polynomials for 2- and 3-strand torus knots in adjoint representation, by universalization of appropriate Rosso-Jones formula. According to universality, these polynomials coincide with adjoined colored HOMFLY and Kauffman polynomials at SL and SO/Sp lines on Vogel's plane, respectively and give their exceptional group's counterparts on exceptional line. We demonstrate that [m,n]=[n,m] topological invariance, when applicable, take place on the entire Vogel's plane. We also suggest the universal form of invariant of figure eight knot in adjoint representation, and suggest existence of such universalization for any knot in adjoint and its descendant representations. Properties of universal polynomials and applications of these results are discussed.

A Practical Guide to Calibration of a GSSHA Hydrologic Model Using ERDC Automated Model Calibration Software - Efficient Local Search

DTIC Science & Technology

2012-02-01

use the ERDC software implementation of the secant LM method that accommodates the PEST model independent interface to calibrate a GSSHA...how the method works. We will also demonstrate how our LM/SLM implementation compares with its counterparts as implemented in the popular PEST ...function values and total model calls for local search to converge) associated with Examples 1 and 3 using the PEST LM/SLM implementations

A Review of the Proposed KIsi Offset-Secant Method for Size-Insensitive Linear-Elastic Fracture Toughness Evaluation

NASA Technical Reports Server (NTRS)

James, Mark; Wells, Doug; Allen, Phillip; Wallin, Kim

2017-01-01

Recently proposed modifications to ASTM E399 would provide a new size-insensitive approach to analyzing the force-displacement test record. The proposed size-insensitive linear-elastic fracture toughness, KIsi, targets a consistent 0.5mm crack extension for all specimen sizes by using an offset secant that is a function of the specimen ligament length. The KIsi evaluation also removes the Pmax/PQ criterion and increases the allowable specimen deformation. These latter two changes allow more plasticity at the crack tip, prompting the review undertaken in this work to ensure the validity of this new interpretation of the force-displacement curve. This paper provides a brief review of the proposed KIsi methodology and summarizes a finite element study into the effects of increased crack tip plasticity on the method given the allowance for additional specimen deformation. The study has two primary points of investigation: the effect of crack tip plasticity on compliance change in the force-displacement record and the continued validity of linear-elastic fracture mechanics to describe the crack front conditions. The analytical study illustrates that linear-elastic fracture mechanics assumptions remain valid at the increased deformation limit; however, the influence of plasticity on the compliance change in the test record is problematic. A proposed revision to the validity criteria for the KIsi test method is briefly discussed.

15 CFR 742.4 - National security.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Requirements” section except those cameras in ECCN 6A003.b.4.b that have a focal plane array with 111,000 or... Albania, Australia, Austria, Belgium, Bulgaria, Canada, Croatia, Cyprus, Czech Republic, Denmark, Estonia....b.4.b that have a focal plane array with 111,000 or fewer elements and a frame rate of 60 Hz or less...

Derivation of the Effective Nonlinear Schrodinger Equations for Dark and Power Law Spatial Plasmon-Polariton Solitons Using Nano Self-Focusing

DTIC Science & Technology

2011-03-01

An e?ective Nonlinear Schr?dinger Equation for propagation is derived for optical dark and power law spatial solitons at the subwavelength with a... soliton amplitude profiles are displayed as a hyperbolic secant function and hold there profile at short distances on the order of centimeters. Dark ...spatial solitons are similar but have hyperbolic tangent type profiles. Dark spatial solitons were first observed by Jerominek in 1985 and Belanger and

Single-layer nanosheets with exceptionally high and anisotropic hydroxyl ion conductivity

PubMed Central

Sun, Pengzhan; Ma, Renzhi; Bai, Xueyin; Wang, Kunlin; Zhu, Hongwei; Sasaki, Takayoshi

2017-01-01

When the dimensionality of layered materials is reduced to the physical limit, an ultimate two-dimensional (2D) anisotropy and/or confinement effect may bring about extraordinary physical and chemical properties. Layered double hydroxides (LDHs), bearing abundant hydroxyl groups covalently bonded within 2D host layers, have been proposed as inorganic anion conductors. However, typical hydroxyl ion conductivities for bulk or lamellar LDHs, generally up to 10−3 S cm−1, are considered not high enough for practical applications. We show that single-layer LDH nanosheets exhibited exceptionally high in-plane conductivities approaching 10−1 S cm−1, which were the highest among anion conductors and comparable to proton conductivities in commercial proton exchange membranes (for example, Nafion). The in-plane conductivities were four to five orders of magnitude higher than the cross-plane or cross-membrane values of restacked LDH nanosheets. This 2D superionic transport characteristic might have great promises in a variety of applications including alkaline fuel cells and water electrolysis. PMID:28439551

Motion-plane dependency of the range of dart throw motion and the effects of tendon action due to finger extrinsic muscles during the motion.

PubMed

Mitsukane, Masahiro; Sekiya, Noboru; Kamono, Arinori; Nakabo, Tohru

2018-03-01

[Purpose] To clarify the motion-plane dependency of the range of dart throw motion and the effects of tendon action due to long finger flexors and extensors during the motion. [Subjects and Methods] Forty healthy subjects attended the experiment, and the active range of wrist motion in seven motion planes was measured with an originally designed apparatus. [Results] The reliability of the measurement was acceptable. The range of dart throw motion depended on the motion planes, with a maximum at around the motion plane of 45° from the sagittal plane (45° of pronation). The tendon action of long finger muscles was shown in dart throw motion except in 45° of pronation. [Conclusion] Motion-plane dependency of the range of dart throw motion exists in healthy subjects. The absence of tendon action due to finger extrinsic muscles in dart throw motion at 45° might be one of the causes of the advantage of dart throw motion.

Test Of A Microwave Amplifier With Superconductive Filter

NASA Technical Reports Server (NTRS)

Bhasin, K. B.; Toncich, S. S.; Chorey, C. M.; Bonetti, R. R.; Williams, A. E.

1995-01-01

Report describes design and low-temperature tests of low-noise GaAs microwave amplifier combined with microstrip band-pass filter. Two versions of microstrip filter used in alternate tests; in one version, microstrips formed as films of high-transition-temperature superconductor Y/Ba/Cu/O on lanthanum aluminate substrate with gold film as ground plane. Other version identical except microstrips as well as ground plane made of gold, normally conductive.

Analysis of the localization of Michelson interferometer fringes using Fourier optics and temporal coherence

NASA Astrophysics Data System (ADS)

Narayanamurthy, C. S.

2009-01-01

Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in Principles of Optics by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer have never been analysed seriously in any book. Because Michelson's interferometer is one of the important and fundamental optical experiments taught at both undergraduate and graduate levels, it would be appropriate to explain the localization of these fringes. In this paper, we analyse the localization of Michelson interferometer fringes using Fourier optics and temporal coherence, and show that they never localize at any plane even at infinity.

Full analytical solution of the bloch equation when using a hyperbolic-secant driving function.

PubMed

Zhang, Jinjin; Garwood, Michael; Park, Jang-Yeon

2017-04-01

The frequency-swept pulse known as the hyperbolic-secant (HS) pulse is popular in NMR for achieving adiabatic spin inversion. The HS pulse has also shown utility for achieving excitation and refocusing in gradient-echo and spin-echo sequences, including new ultrashort echo-time imaging (e.g., Sweep Imaging with Fourier Transform, SWIFT) and B 1 mapping techniques. To facilitate the analysis of these techniques, the complete theoretical solution of the Bloch equation, as driven by the HS pulse, was derived for an arbitrary state of initial magnetization. The solution of the Bloch-Riccati equation for transverse and longitudinal magnetization for an arbitrary initial state was derived analytically in terms of HS pulse parameters. The analytical solution was compared with the solutions using both the Runge-Kutta method and the small-tip approximation. The analytical solution was demonstrated on different initial states at different frequency offsets with/without a combination of HS pulses. Evolution of the transverse magnetization was influenced significantly by the choice of HS pulse parameters. The deviation of the magnitude of the transverse magnetization, as obtained by comparing the small-tip approximation to the analytical solution, was < 5% for flip angles < 30 °, but > 10% for the flip angles > 40 °. The derived analytical solution provides insights into the influence of HS pulse parameters on the magnetization evolution. Magn Reson Med 77:1630-1638, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

[The effect of mandibular distraction on the maxilla growth in children with hemifacial microsomia].

PubMed

Yang, Renkai; Tang, Xiaojun; Shi, Lei; Yin, Lin; Yang, Bin; Yin, Hongyu; Liu, Wei; Zhang, Zhiyong

2014-11-01

To analyze the effect of mandibular distraction on the maxilla growth in children with hemifacial microsomia through measurement with the posterior-anterior cephalometric X-ray films and Three-dimensional CT reconstruction images. The deviation angular of maxilla occlusion plane and nasal base plane from the infra-orbital plane were measured on the posterior-anterior cephalometric X-ray films in 22 patients before and half a year after operation. The vertical distance from the midpoint of 5th teeth alveolar and the lowest point of maxillary sinus to reference plane were measured on 3D reconstruction images in 15 patients. The data were statistically analyzed. On posterior-anterior cephalometric X-ray films, the cant of occlusion plane were significantly reduced (P < 0.05), While the angular of nasal base plane and the infra-orbital plane had no significant change. On 3D reconstruction images, all the detection points had significantly declined except the lowest point of maxillary sinus on normal side. Distraction osteogenesis of mandible can promote the growth of the maxilla in children with HFM, the accelerated growth parts include alveolar bone and maxillary sinus.

Test plane uniformity analysis for the MSFC solar simulator lamp array

NASA Technical Reports Server (NTRS)

Griner, D. B.

1976-01-01

A preliminary analysis was made on the solar simulator lamp array. It is an array of 405 tungsten halogen lamps with Fresnel lenses to achieve the required spectral distribution and collimation. A computer program was developed to analyze lamp array performance at the test plane. Measurements were made on individual lamp lens combinations to obtain data for the computer analysis. The analysis indicated that the performance of the lamp array was about as expected, except for a need to position the test plane within 2.7 m of the lamp array to achieve the desired 7 percent uniformity of illumination tolerance.

50 CFR 300.161 - Alternatives and exceptions.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., must reflect that number or label. (4) A conveyance (truck, plane, boat, etc.) is not considered a... shipping documents; (2) Fish or shellfish contained in retail consumer packages labeled pursuant to the...

On the use of L-band multipolarization airborne SAR for surveys of crops, vineyards, and orchards in a California irrigated agricultural region

NASA Technical Reports Server (NTRS)

Paris, J. F.

1985-01-01

The airborne L-band synthetic aperture radar (SAR) collected multipolarization calibrated image data over an irrigated agricultural test site near Fresno, CA, on March 6, 1984. The conclusions of the study are as follows: (1) the effects of incidence angle on the measured backscattering coefficients could be removed by using a correction factor equal to the secant of the angle raised to the 1.4 power, (2) for this scene and time of year, the various polarization channels were highly correlated such that the use of more than one polarization added little to the ability of the radar to discriminate vegetation type or condition; the exception was barley which separated from vineyards only when a combination of like and cross polarization data were used (polarization was very useful for corn identification in fall crops), (3) an excellent separation between herbaceous vegetation (alfalfa, barley, and oats) or bare fields and trees in orchards existed in brightness was well correlated to alfalfa height or biomass, especially for the HH polarization combination, (5) vineyards exhibited a narrow range of brightnesses with no systematic effects of type or number of stakes nor of number of wires in the trellises nor of the size of the vines, (6) within the orchard classes, areal biomass characterized by basal area differences caused radar image brightness differences for small to medium trees but not for medium to large trees.

Well Conditioned Formulations for Open Surface Scattering

DTIC Science & Technology

2008-08-01

region on the negative real half of the com- plex plane and tend to cluster about a few points. With few exceptions12, the eigenvalues have converged...a relatively small region on the negative real half of the complex plane and they tend to cluster about a few points. We were surprised, however, to...theory and the results from a numerical implementation. We also discuss a 2d extension of the Poincare -Bertrand identity could be used to develop an

49 CFR 572.177 - Test conditions and instrumentation.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) except as noted, with channel frequency classes as follows: (1) Pendulum acceleration, CFC 180, (2) Pendulum D-plane rotation (if transducer is used), CFC 60, (3) Torso flexion pulling force (if transducer...

49 CFR 572.177 - Test conditions and instrumentation.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) except as noted, with channel frequency classes as follows: (1) Pendulum acceleration, CFC 180, (2) Pendulum D-plane rotation (if transducer is used), CFC 60, (3) Torso flexion pulling force (if transducer...

49 CFR 572.177 - Test conditions and instrumentation.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) except as noted, with channel frequency classes as follows: (1) Pendulum acceleration, CFC 180, (2) Pendulum D-plane rotation (if transducer is used), CFC 60, (3) Torso flexion pulling force (if transducer...

Dark Murky Clouds in the Bright Milky Way

NASA Image and Video Library

2011-08-24

This infrared image from NASA Wide-field Infrared Survey Explorer shows exceptionally cold, dense cloud cores seen in silhouette against the bright diffuse infrared glow of the plane of the Milky Way galaxy.

On the transferability of RegCM4: Europe, Africa and Asia

NASA Astrophysics Data System (ADS)

Belda, Michal; Halenka, Tomas

2013-04-01

Simulations driven by ERA-interim reanalysis for CORDEX domains covering Europe, Africa and Asia have been performed using RegCM4 at 50 km resolution. The same settings are used in basic simulations and preliminary evaluation of model performance for individual regions will be presented. Several settings of different options is tested and sensitivity of selected ones will be shown in individual regions. Secant Mercator projection is introduced for Africa providing more efficient model geometry setting, the impact of proper emissivity inclusion is compared especially for Africa and Asia desserts. CRU data are used for the validation.

50 CFR 14.82 - Alternatives and exceptions to the marking requirement.

Code of Federal Regulations, 2010 CFR

2010-10-01

... subcontainer containing a venomous species must be clearly marked as venomous. (4) A conveyance (truck, plane... shipping documents; (2) Fish or shellfish contained in retail consumer packages labeled pursuant to the...

Few-layered MnO2/SWCNT hybrid in-plane supercapacitor with high energy density

NASA Astrophysics Data System (ADS)

Dutta, Shibsankar; Pal, Shreyasi; De, Sukanta

2018-05-01

In this present work we have synthesized few layered MnO2 nanosheets by mixed solvent exfoliation process for the application as electrode material of in-plane supercapacitor. The Structure and surface morphology of the as prepared samples are characterized by Raman, Transmission electron microscopy and Scanning electron microscopy. The patterns of the hybrids were directly fabricated by (50: 50 wt %) mixture of MnO2 and SWCNT dispersions with the help of a customized mask, and directly transferred onto a flexible PET substrate. Remarkably, the prepared in-plane supercapacitors deliver high energy density of 2.62mWh/cm2. Furthermore, our supercapacitors shows exceptional flexibility and stable performance under bending conditions

Tissue elasticity of in vivo skeletal muscles measured in the transverse and longitudinal planes using shear wave elastography.

PubMed

Chino, Kentaro; Kawakami, Yasuo; Takahashi, Hideyuki

2017-07-01

The aim of the present study was to measure in vivo skeletal muscle elasticity in the transverse and longitudinal planes using shear wave elastography and then to compare the image stability, measurement values and measurement repeatability between these imaging planes. Thirty-one healthy males participated in this study. Tissue elasticity (shear wave velocity) of the medial gastrocnemius, rectus femoris, biceps brachii and rectus abdominis was measured in both the transverse and longitudinal planes using shear wave elastography. Image stability was evaluated by the standard deviation of the colour distribution in the shear wave elastography image. Measurement repeatability was assessed by the coefficient of variance obtained from three measurement values. Image stability of all tested muscles was significantly higher in the longitudinal plane (P<0·001), but measurement repeatability did not differ significantly between the imaging planes (P>0·05), except in the biceps brachii (P = 0·001). Measurement values of the medial gastrocnemius, rectus femoris and biceps brachii were significantly different between the imaging planes (P<0·001). Image stability and measurement values of shear wave elastography images varied with imaging plane, which indicates that imaging plane should be considered when measuring skeletal muscle tissue elasticity by shear wave elastography. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

15 CFR 742.4 - National security.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Requirements” section except those cameras in ECCN 6A003.b.4.b that have a focal plane array with 111,000 or..., South Korea, Spain, Sweden, Switzerland, Turkey, and the United Kingdom for those cameras in ECCN 6A003...

15 CFR 742.4 - National security.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Requirements” section except those cameras in ECCN 6A003.b.4.b that have a focal plane array with 111,000 or..., South Korea, Spain, Sweden, Switzerland, Turkey, and the United Kingdom for those cameras in ECCN 6A003...

15 CFR 742.4 - National security.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Requirements” section except those cameras in ECCN 6A003.b.4.b that have a focal plane array with 111,000 or..., South Korea, Spain, Sweden, Switzerland, Turkey, and the United Kingdom for those cameras in ECCN 6A003...

15 CFR 742.4 - National security.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Requirements” section except those cameras in ECCN 6A003.b.4.b that have a focal plane array with 111,000 or..., South Korea, Spain, Sweden, Switzerland, Turkey, and the United Kingdom for those cameras in ECCN 6A003...

Aircraft digital control design methods

NASA Technical Reports Server (NTRS)

Powell, J. D.; Parsons, E.; Tashker, M. G.

1976-01-01

Variations in design methods for aircraft digital flight control are evaluated and compared. The methods fall into two categories; those where the design is done in the continuous domain (or s plane) and those where the design is done in the discrete domain (or z plane). Design method fidelity is evaluated by examining closed loop root movement and the frequency response of the discretely controlled continuous aircraft. It was found that all methods provided acceptable performance for sample rates greater than 10 cps except the uncompensated s plane design method which was acceptable above 20 cps. A design procedure based on optimal control methods was proposed that provided the best fidelity at very slow sample rates and required no design iterations for changing sample rates.

Giant asymmetric self-phase modulation in superconductor thin films

NASA Astrophysics Data System (ADS)

Robson, Charles W.; Biancalana, Fabio

2018-04-01

Self-phase modulation (SPM) of light pulses is found to occur strongly, at low incident intensities, in the coupling of light with superconductors. We develop a theory from a synthesis of the time-dependent Ginzburg-Landau (TDGL) equation and basic electrodynamics which shows the strongly non-linear phase accumulated in the interaction. Unusually, the SPM of the pulse in this system is found to be highly asymmetric, producing a strongly redshifted spectrum when interacting with a superconducting thin film, and it develops in just a few nanometers of propagation. In this paper we present theoretical results and simulations in the THz regime, for both hyperbolic secant and supergaussian-shaped pulses.

Nonlinear behavior of matrix-inclusion composites under high confining pressure: application to concrete and mortar

NASA Astrophysics Data System (ADS)

Le, Tuan Hung; Dormieux, Luc; Jeannin, Laurent; Burlion, Nicolas; Barthélémy, Jean-François

2008-08-01

This paper is devoted to a micromechanics-based simulation of the response of concrete to hydrostatic and oedometric compressions. Concrete is described as a composite made up of a cement matrix in which rigid inclusions are embedded. The focus is put on the role of the interface between matrix and inclusion which represent the interfacial transition zone (ITZ). A plastic behavior is considered for both the matrix and the interfaces. The effective response of the composite is derived from the modified secant method adapted to the situation of imperfect interfaces. To cite this article: T.H. Le et al., C. R. Mecanique 336 (2008).

Anatomic study of the canine stifle using low-field magnetic resonance imaging (MRI) and MRI arthrography.

PubMed

Pujol, Esteban; Van Bree, Henri; Cauzinille, Laurent; Poncet, Cyrill; Gielen, Ingrid; Bouvy, Bernard

2011-06-01

To investigate the use of low-field magnetic resonance imaging (MRI) and MR arthrography in normal canine stifles and to compare MRI images to gross dissection. Descriptive study. Adult canine pelvic limbs (n=17). Stifle joints from 12 dogs were examined by orthopedic and radiographic examination, synovial fluid analysis, and MRI performed using a 0.2 T system. Limbs 1 to 7 were used to develop the MR and MR arthrography imaging protocol. Limbs 8-17 were studied with the developed MR and MR arthrography protocol and by gross dissection. Three sequences were obtained: T1-weighted spin echo (SE) in sagittal, dorsal, and transverse plane; T2-weighted SE in sagittal plane and T1-gradient echo in sagittal plane. Specific bony and soft tissue structures were easily identifiable with the exception of articular cartilage. The cranial and caudal cruciate ligaments were identified. Medial and lateral menisci were seen as wedge-shaped hypointense areas. MR arthrography permitted further delineation of specific structures. MR images corresponded with gross dissection morphology. With the exception of poor delineation of articular cartilage, a low-field MRI and MR arthrography protocol provides images of adequate quality to assess the normal canine stifle joint. © Copyright 2011 by The American College of Veterinary Surgeons.

VAST PLANES OF SATELLITES IN A HIGH-RESOLUTION SIMULATION OF THE LOCAL GROUP: COMPARISON TO ANDROMEDA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gillet, N.; Ocvirk, P.; Aubert, D.

2015-02-10

We search for vast planes of satellites (VPoS) in a high-resolution simulation of the Local Group performed by the CLUES project, which improves significantly the resolution of previous similar studies. We use a simple method for detecting planar configurations of satellites, and validate it on the known plane of M31. We implement a range of prescriptions for modeling the satellite populations, roughly reproducing the variety of recipes used in the literature, and investigate the occurrence and properties of planar structures in these populations. The structure of the simulated satellite systems is strongly non-random and contains planes of satellites, predominantly co-rotating,more » with, in some cases, sizes comparable to the plane observed in M31 by Ibata et al. However, the latter is slightly richer in satellites, slightly thinner, and has stronger co-rotation, which makes it stand out as overall more exceptional than the simulated planes, when compared to a random population. Although the simulated planes we find are generally dominated by one real structure forming its backbone, they are also partly fortuitous and are thus not kinematically coherent structures as a whole. Provided that the simulated and observed planes of satellites are indeed of the same nature, our results suggest that the VPoS of M31 is not a coherent disk and that one-third to one-half of its satellites must have large proper motions perpendicular to the plane.« less

A Study of the Gamma-Ray Burst Fundamental Plane

DOE PAGES

Dainotti, M. G.; Hernandez, X.; Postnikov, S.; ...

2017-10-17

Long gamma-ray bursts (GRBs) with a plateau phase in their X-ray afterglows obey a 3D relation, between the rest-frame time at the end of the plateau, T a, its corresponding X-ray luminosity, L a, and the peak luminosity in the prompt emission, L peak. This 3D relation identifies a GRB fundamental plane whose existence we here confirm. Here we include the most recent GRBs observed by Swift to define a "gold sample" (45 GRBs) and obtain an intrinsic scatter about the plane compatible within 1σ with the previous result. We compare GRB categories, such as short GRBs with extended emissionmore » (SEE), X-ray flashes, GRBs associated with supernovae, a sample of only long-duration GRBs (132), selected from the total sample by excluding GRBs of the previous categories, and the gold sample, composed by GRBs with light curves with good data coverage and relatively flat plateaus. We find that the relation planes for each of these categories are not statistically different from the gold fundamental plane, with the exception of the SSE, which are hence identified as a physically distinct class. The gold fundamental plane has an intrinsic scatter smaller than any plane derived from the other sample categories. Thus, the distance of any particular GRB category from this plane becomes a key parameter. We computed the several category planes with T a as a dependent parameter obtaining for each category smaller intrinsic scatters (reaching a reduction of 24% for the long GRBs). The fundamental plane is independent from several prompt and afterglow parameters.« less

Decentralized Quasi-Newton Methods

NASA Astrophysics Data System (ADS)

Eisen, Mark; Mokhtari, Aryan; Ribeiro, Alejandro

2017-05-01

We introduce the decentralized Broyden-Fletcher-Goldfarb-Shanno (D-BFGS) method as a variation of the BFGS quasi-Newton method for solving decentralized optimization problems. The D-BFGS method is of interest in problems that are not well conditioned, making first order decentralized methods ineffective, and in which second order information is not readily available, making second order decentralized methods impossible. D-BFGS is a fully distributed algorithm in which nodes approximate curvature information of themselves and their neighbors through the satisfaction of a secant condition. We additionally provide a formulation of the algorithm in asynchronous settings. Convergence of D-BFGS is established formally in both the synchronous and asynchronous settings and strong performance advantages relative to first order methods are shown numerically.

Baseline tensile tests of composite materials for LDEF (Long Duration Exposure Facility) exposure

NASA Technical Reports Server (NTRS)

Witte, William G.

1987-01-01

Tensile specimens of five graphite fiber reinforced composite materials were tested at room temperature to provide baseline data for similar specimens exposed to the space environment in low-Earth orbit on the NASA Long Duration Exposure Facility. All specimens were 4-ply (+ or - 45 deg)s layups; at least five replicate specimens were tested for each parameter evaluated. Three epoxy-matrix materials and two polysulfone-matrix materials, several fiber volume fractions, and two sizes of specimen were evaluated. Stress-strain and Poisson's ratio-stress curves, ultimate stress, strain at failure, secant modulus at 0.004 strain, inplane shear stress-strain curves, and unidirectional shear modulus at .004 shear strain are presented.

Attenuation, dispersion and nonlinearity effects in graphene-based waveguides

PubMed Central

Mota, João Cesar Moura; Sombra, Antonio Sergio Bezerra

2015-01-01

Summary We simulated and analyzed in detail the behavior of ultrashort optical pulses, which are typically used in telecommunications, propagating through graphene-based nanoribbon waveguides. In this work, we showed the changes that occur in the Gaussian and hyperbolic secant input pulses due to the attenuation, high-order dispersive effects and nonlinear effects. We concluded that it is possible to control the shape of the output pulses with the value of the input signal power and the chemical potential of the graphene nanoribbon. We believe that the obtained results will be highly relevant since they can be applied to other nanophotonic devices, for example, filters, modulators, antennas, switches and other devices. PMID:26171299

Defining the origins of electron transfer at screen-printed graphene-like and graphite electrodes: MoO2 nanowire fabrication on edge plane sites reveals electrochemical insights.

PubMed

Rowley-Neale, Samuel J; Brownson, Dale A C; Banks, Craig E

2016-08-18

Molybdenum (di)oxide (MoO2) nanowires are fabricated onto graphene-like and graphite screen-printed electrodes (SPEs) for the first time, revealing crucial insights into the electrochemical properties of carbon/graphitic based materials. Distinctive patterns observed in the electrochemical process of nanowire decoration show that electron transfer occurs predominantly on edge plane sites when utilising SPEs fabricated/comprised of graphitic materials. Nanowire fabrication along the edge plane sites (and on edge plane like-sites/defects) of graphene/graphite is confirmed with Cyclic Voltammetry, Scanning Electron Microscopy (SEM) and Raman Spectroscopy. Comparison of the heterogeneous electron transfer (HET) rate constants (k°) at unmodified and nanowire coated SPEs show a reduction in the electrochemical reactivity of SPEs when the edge plane sites are effectively blocked/coated with MoO2. Throughout the process, the basal plane sites of the graphene/graphite electrodes remain relatively uncovered; except when the available edge plane sites have been utilised, in which case MoO2 deposition grows from the edge sites covering the entire surface of the electrode. This work clearly illustrates the distinct electron transfer properties of edge and basal plane sites on graphitic materials, indicating favourable electrochemical reactivity at the edge planes in contrast to limited reactivity at the basal plane sites. In addition to providing fundamental insights into the electron transfer properties of graphite and graphene-like SPEs, the reported simple, scalable, and cost effective formation of unique and intriguing MoO2 nanowires realised herein is of significant interest for use in both academic and commercial applications.

A Study of the Gamma-Ray Burst Fundamental Plane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dainotti, M. G.; Hernandez, X.; Postnikov, S.

2017-10-20

Long gamma-ray bursts (GRBs) with a plateau phase in their X-ray afterglows obey a 3D relation, between the rest-frame time at the end of the plateau, T {sub a} , its corresponding X-ray luminosity, L {sub a} , and the peak luminosity in the prompt emission, L {sub peak}. This 3D relation identifies a GRB fundamental plane whose existence we here confirm. Here we include the most recent GRBs observed by Swift to define a “gold sample” (45 GRBs) and obtain an intrinsic scatter about the plane compatible within 1 σ with the previous result. We compare GRB categories, suchmore » as short GRBs with extended emission (SEE), X-ray flashes, GRBs associated with supernovae, a sample of only long-duration GRBs (132), selected from the total sample by excluding GRBs of the previous categories, and the gold sample, composed by GRBs with light curves with good data coverage and relatively flat plateaus. We find that the relation planes for each of these categories are not statistically different from the gold fundamental plane, with the exception of the SSE, which are hence identified as a physically distinct class. The gold fundamental plane has an intrinsic scatter smaller than any plane derived from the other sample categories. Thus, the distance of any particular GRB category from this plane becomes a key parameter. We computed the several category planes with T {sub a} as a dependent parameter obtaining for each category smaller intrinsic scatters (reaching a reduction of 24% for the long GRBs). The fundamental plane is independent from several prompt and afterglow parameters.« less

Lower incisor inclination regarding different reference planes.

PubMed

Zataráin, Brenda; Avila, Josué; Moyaho, Angeles; Carrasco, Rosendo; Velasco, Carmen

2016-09-01

The purpose of this study was to assess the degree of lower incisor inclination with respect to different reference planes. It was an observational, analytical, longitudinal, prospective study conducted on 100 lateral cephalograms which were corrected according to the photograph in natural head position in order to draw the true vertical plane (TVP). The incisor mandibular plane angle (IMPA) was compensated to eliminate the variation of the mandibular plane growth type with the formula "FMApx.- 25 (FMA) + IMPApx. = compensated IMPA (IMPACOM)". As the data followed normal distribution determined by the KolmogorovSmirnov test, parametric tests were used for the statistical analysis, Ttest, ANOVA and Pearson coefficient correlation test. Statistical analysis was performed using a statistical significance of p <0.05. There is correlation between TVP and NB line (NB) (0.8614), Frankfort mandibular incisor angle (FMIA) (0.8894), IMPA (0.6351), Apo line (Apo) (0.609), IMPACOM (0.8895) and McHorris angle (MH) (0.7769). ANOVA showed statistically significant differences between the means for the 7 variables with 95% confidence level, P=0.0001. The multiple range test showed no significant difference among means: APoNB (0.88), IMPAMH (0.36), IMPANB (0.65), FMIAIMPACOM (0.01), FMIATVP (0.18), TVPIMPACOM (0.17). There was correlation among all reference planes. There were statistically significant differences among the means of the planes measured, except for IMPACOM, FMIA and TVP. The IMPA differed significantly from the IMPACOM. The compensated IMPA and the FMIA did not differ significantly from the TVP. The true horizontal plane was mismatched with Frankfort plane in 84% of the sample with a range of 19°. The true vertical plane is adequate for measuring lower incisor inclination. Sociedad Argentina de Investigación Odontológica.

Analytic model for the long-term evolution of circular Earth satellite orbits including lunar node regression

NASA Astrophysics Data System (ADS)

Zhu, Ting-Lei; Zhao, Chang-Yin; Zhang, Ming-Jiang

2017-04-01

This paper aims to obtain an analytic approximation to the evolution of circular orbits governed by the Earth's J2 and the luni-solar gravitational perturbations. Assuming that the lunar orbital plane coincides with the ecliptic plane, Allan and Cook (Proc. R. Soc. A, Math. Phys. Eng. Sci. 280(1380):97, 1964) derived an analytic solution to the orbital plane evolution of circular orbits. Using their result as an intermediate solution, we establish an approximate analytic model with lunar orbital inclination and its node regression be taken into account. Finally, an approximate analytic expression is derived, which is accurate compared to the numerical results except for the resonant cases when the period of the reference orbit approximately equals the integer multiples (especially 1 or 2 times) of lunar node regression period.

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

Vision Aided Inertial Navigation System Augmented with a Coded Aperture

DTIC Science & Technology

2011-03-24

as the change in blur at different distances from the pixel plane can be inferred. Cameras with a micro lens array (called plenoptic cameras...images from 8 slightly different perspectives [14,43]. Dappled photography is a similar to the plenoptic camera approach except that a cosine mask

Teaching of clinical ultrasonography to undergraduates: students as mentors.

PubMed

García de Casasola Sánchez, G; González Peinado, D; Sánchez Gollarte, A; Muñoz Aceituno, E; Peña Vázquez, I; Torres Macho, J

2015-05-01

Ultrasonography is a highly useful diagnostic technique that supplements traditional physical examinations. To demonstrate that students previously trained in clinical ultrasonography are capable of instructing other students in a similar manner in a short period of time ("peer mentoring"). Five medical students in their 5th year, trained in abdominal and cardiac ultrasonography by physicians with experience, instructed 24 other students in the same procedure. The training consisted of an online theoretical course and practical training lasting about 12hours, in which each student had to perform 6 basic abdominal planes and 4 basic cardiac planes on 20 healthy volunteers. Subsequently, the students underwent an objective assessment test on healthy models performed by expert physicians in clinical ultrasonography. The students managed to correctly identify 90.2% of the basic abdominal planes, except for the left coronal (spleen and left kidney) and subcostal (gallbladder) planes, with slightly lower success rates of 82.5% and 80%, respectively. Due to the greater difficulty of obtaining cardiac planes, the success rate was lower: 70.3%, in the subxiphoid, short parasternal and four chamber planes. The cardiac plane with the fewest errors in identification was the parasternal long plane (90% success). We observed no statistically significant differences between the results (teaching capacity) of the various mentors. Medical students are capable of instructing other colleagues (peer mentoring) on the basic aspects of abdominal and cardiac ultrasonography after a relatively short training period. Copyright © 2014 Elsevier España, S.L.U. y Sociedad Española de Medicina Interna (SEMI). All rights reserved.

Three-dimensional Frankfort horizontal plane for 3D cephalometry: a comparative assessment of conventional versus novel landmarks and horizontal planes.

PubMed

Pittayapat, Pisha; Jacobs, Reinhilde; Bornstein, Michael M; Odri, Guillaume A; Lambrichts, Ivo; Willems, Guy; Politis, Constantinus; Olszewski, Raphael

2018-05-25

To assess the reproducibility of landmarks in three dimensions that determine the Frankfort horizontal plane (FH) as well as two new landmarks, and to evaluate the angular differences of newly introduced planes to the FH. Three-dimensional (3D) surface models were created from CBCT scans of 26 dry human skulls. Porion (Po), orbitale (Or), internal acoustic foramen (IAF), and zygomatico-maxillary suture (ZyMS) were indicated in the software by three observers twice with a 4-week interval. Angles between two FHs (FH 1: Or-R, Or-L, mid-Po; FH 2: Po-R, Po-L, mid-Or) and between FHs and new planes (Plane 1-6) were measured. Coordinates were exported to a spreadsheet. A statistical analysis was performed to define the landmark reproducibility and 3D angles. Intra- and inter-observer landmark reproducibility showed mean difference more than 1 mm for x-coordinates of all landmarks except IAF. IAF showed significantly better reproducibility than other landmarks (P < 0.0018). The mean angular difference between FH 1 and FH 2 was 0.7 degrees. Plane 3, connecting Or-R, Or-L and mid-IAF, and Plane 4, connecting Po-R, Po-L and mid-ZyMS, both showed an angular difference of less than 1 degree when compared to FHs. This study revealed poor reproducibility of the traditional FH landmarks on the x-axis and good reproducibility of a new landmark tested to replace Po, the IAF. Yet, Or showed superior results compared to ZyMS. The potential of using new horizontal planes was demonstrated. Future studies should focus on identification of a valid alternative for Or and ZyMS and on clinical implementation of the findings.

Orbiter/payload proximity operations: Lateral approach technique

NASA Technical Reports Server (NTRS)

Bell, J. A.; Jones, H. L.; Mcadoo, S. F.

1977-01-01

The lateral approach is presented for proximity operations associated with the retrieval of free flying payloads. An out of plane final approach emphasizing onboard software support is recommended for all except the latter segment of the final approach in which manual control is considered mandatory. An overall assessment of various candidate proximity operations techniques are made.

21 CFR 1020.31 - Radiographic equipment.

Code of Federal Regulations, 2012 CFR

2012-04-01

... fluoroscopic imaging or for recording images from the fluoroscopic image receptor, or computed tomography x-ray... and time, a preset number of pulses, or a preset radiation exposure to the image receptor. (i) Except... provided to indicate when the axis of the x-ray beam is perpendicular to the plane of the image receptor...

21 CFR 1020.31 - Radiographic equipment.

Code of Federal Regulations, 2013 CFR

2013-04-01

... fluoroscopic imaging or for recording images from the fluoroscopic image receptor, or computed tomography x-ray... and time, a preset number of pulses, or a preset radiation exposure to the image receptor. (i) Except... provided to indicate when the axis of the x-ray beam is perpendicular to the plane of the image receptor...

21 CFR 1020.31 - Radiographic equipment.

Code of Federal Regulations, 2014 CFR

2014-04-01

... fluoroscopic imaging or for recording images from the fluoroscopic image receptor, or computed tomography x-ray... and time, a preset number of pulses, or a preset radiation exposure to the image receptor. (i) Except... provided to indicate when the axis of the x-ray beam is perpendicular to the plane of the image receptor...

Optics of short-pitch deformed-helix ferroelectric liquid crystals: Symmetries, exceptional points, and polarization-resolved angular patterns

NASA Astrophysics Data System (ADS)

Kiselev, Alexei D.; Chigrinov, Vladimir G.

2014-10-01

In order to explore electric-field-induced transformations of polarization singularities in the polarization-resolved angular (conoscopic) patterns emerging after deformed-helix ferroelectric liquid crystal (DHFLC) cells with subwavelength helix pitch, we combine the transfer matrix formalism with the results for the effective dielectric tensor of biaxial FLCs evaluated using an improved technique of averaging over distorted helical structures. Within the framework of the transfer matrix method, we deduce a number of symmetry relations and show that the symmetry axis of L lines (curves of linear polarization) is directed along the major in-plane optical axis which rotates under the action of the electric field. When the angle between this axis and the polarization plane of incident linearly polarized light is above its critical value, the C points (points of circular polarization) appear in the form of symmetrically arranged chains of densely packed star-monstar pairs. We also emphasize the role of phase singularities of a different kind and discuss the enhanced electro-optic response of DHFLCs near the exceptional point where the condition of zero-field isotropy is fulfilled.

Forward volume and surface magnetostatic modes in an yttrium iron garnet film for out-of-plane magnetic fields: Theory and experiment

NASA Astrophysics Data System (ADS)

Lim, Jinho; Bang, Wonbae; Trossman, Jonathan; Amanov, Dovran; Ketterson, John B.

2018-05-01

We present experimental and theoretical results on the propagation of magnetostatic spin waves in a film of yttrium iron garnet (YIG) for out-of-plane magnetic fields for which propagation in opposite directions is nonreciprocal in the presence of a metal layer. The plane studied is defined by the film normal n and n × k where k is the wave vector of the mode. Spin waves in this setting are classified as forward volume waves or surface waves and display non-reciprocity in the presence of an adjacent metal layer except for when H//n. The measurements are carried out in a transmission geometry, and a microwave mixer is used to measure the change of phase, and with it the evolution of wavevector, of the arriving spin wave with external magnetic field.

Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections

PubMed Central

Morelli, Francesco; Amico, Cosimo; Salvatore, Walter; Squeglia, Nunziante; Stacul, Stefano

2017-01-01

Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with circular section subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness. PMID:28773028

Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections.

PubMed

Morelli, Francesco; Amico, Cosimo; Salvatore, Walter; Squeglia, Nunziante; Stacul, Stefano

2017-06-18

Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with the circular sections subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness.

Ultra-flat SPM-broadened spectra in a highly nonlinear fiber using parabolic pulses formed in a fiber Bragg grating

NASA Astrophysics Data System (ADS)

Parmigiani, Francesca; Finot, Christophe; Mukasa, Kazunori; Ibsen, Morten; Roelens, Michael A.; Petropoulos, Periklis; Richardson, David J.

2006-08-01

We propose a new method for generating flat self-phase modulation (SPM)-broadened spectra based on seeding a highly nonlinear fiber (HNLF) with chirp-free parabolic pulses generated using linear pulse shaping in a superstructured fiber Bragg grating (SSFBG). We show that the use of grating reshaped parabolic pulses allows substantially better performance in terms of the extent of SPM-based spectral broadening and flatness relative to conventional hyperbolic secant (sech) pulses. We demonstrate both numerically and experimentally the generation of SPM-broadened pulses centred at 1542 nm with 92% of the pulse energy remaining within the 29 nm 3 dB spectral bandwidth. Applications in spectra slicing and pulse compression are demonstrated.

High-speed polarization-encoded quantum key distribution based on silicon photonic integrated devices

NASA Astrophysics Data System (ADS)

Bunandar, Darius; Urayama, Junji; Boynton, Nicholas; Martinez, Nicholas; Derose, Christopher; Lentine, Anthony; Davids, Paul; Camacho, Ryan; Wong, Franco; Englund, Dirk

We present a compact polarization-encoded quantum key distribution (QKD) transmitter near a 1550-nm wavelength implemented on a CMOS-compatible silicon-on-insulator photonics platform. The transmitter generates arbitrary polarization qubits at gigahertz bandwidth with an extinction ratio better than 30 dB using high-speed carrier-depletion phase modulators. We demonstrate the performance of this device by generating secret keys at a rate of 1 Mbps in a complete QKD field test. Our work shows the potential of using advanced photonic integrated circuits to enable high-speed quantum-secure communications. This work was supported by the SECANT QKD Grand Challenge, the Samsung Global Research Outreach Program, and the Air Force Office of Scientific Research.

Do Other Planets Have Summer?

ERIC Educational Resources Information Center

Nelson, George

2005-01-01

It's important to keep two things in mind when thinking about the cause of the seasons: (1) Earth and all the other planets except Pluto and Mercury move around the Sun in almost perfect circles, getting neither closer nor farther away from the Sun during the year; and (2) Earth's rotation axis is tilted with respect to the plane of its orbit…

Preliminary study of tug-glider freight systems utilizing a Boeing 747 as the tug

NASA Technical Reports Server (NTRS)

Heyson, H. H.; Foss, W. E., Jr.

1977-01-01

Performance of the tug-glider system was severely limited by ground run. In most cases studied, additional engines were necessary. Except at short ranges for which additional payload were carried in the tow plane, the productivity of the basic aircraft was degraded by a reduction in cruise speed necessitated by the glider drag. Excessive aspect ratios did not improve system performance because of the increase in glider wing weight. Powered gliders using a tow plane only for takeoff and climb had the potential for a major reduction in fuel consumption. Uncertainty of restrictive regulatory action and the apparently increased airborne investment per unit productivity are obstacles to commercial development.

Generalization of the subsonic kernel function in the s-plane, with applications to flutter analysis

NASA Technical Reports Server (NTRS)

Cunningham, H. J.; Desmarais, R. N.

1984-01-01

A generalized subsonic unsteady aerodynamic kernel function, valid for both growing and decaying oscillatory motions, is developed and applied in a modified flutter analysis computer program to solve the boundaries of constant damping ratio as well as the flutter boundary. Rates of change of damping ratios with respect to dynamic pressure near flutter are substantially lower from the generalized-kernel-function calculations than from the conventional velocity-damping (V-g) calculation. A rational function approximation for aerodynamic forces used in control theory for s-plane analysis gave rather good agreement with kernel-function results, except for strongly damped motion at combinations of high (subsonic) Mach number and reduced frequency.

A novel robot for imposing perturbations during overground walking: mechanism, control and normative stepping responses.

PubMed

Olenšek, Andrej; Zadravec, Matjaž; Matjačić, Zlatko

2016-06-11

The most common approach to studying dynamic balance during walking is by applying perturbations. Previous studies that investigated dynamic balance responses predominantly focused on applying perturbations in frontal plane while walking on treadmill. The goal of our work was to develop balance assessment robot (BAR) that can be used during overground walking and to assess normative balance responses to perturbations in transversal plane in a group of neurologically healthy individuals. BAR provides three passive degrees of freedom (DoF) and three actuated DoF in pelvis that are admittance-controlled in such a way that the natural movement of pelvis is not significantly affected. In this study BAR was used to assess normative balance responses in neurologically healthy individuals by applying linear perturbations in frontal and sagittal planes and angular perturbations in transversal plane of pelvis. One way repeated measure ANOVA was used to statistically evaluate the effect of selected perturbations on stepping responses. Standard deviations of assessed responses were similar in unperturbed and perturbed walking. Perturbations in frontal direction evoked substantial pelvis displacement and caused statistically significant effect on step length, step width and step time. Likewise, perturbations in sagittal plane also caused statistically significant effect on step length, step width and step time but with less explicit impact on pelvis movement in frontal plane. On the other hand, except from substantial pelvis rotation angular perturbations did not have substantial effect on pelvis movement in frontal and sagittal planes while statistically significant effect was noted only in step length and step width after perturbation in clockwise direction. Results indicate that the proposed device can repeatedly reproduce similar experimental conditions. Results also suggest that "stepping strategy" is the dominant strategy for coping with perturbations in frontal plane, perturbations in sagittal plane are to greater extent handled by "ankle strategy" while angular perturbations in transversal plane do not pose substantial challenge for balance. Results also show that specific perturbation in general elicits responses that extend also to other planes of movement that are not directly associated with plane of perturbation as well as to spatio temporal parameters of gait.

Asymptotic dynamics of the exceptional Bianchi cosmologies

NASA Astrophysics Data System (ADS)

Hewitt, C. G.; Horwood, J. T.; Wainwright, J.

2003-05-01

In this paper we give, for the first time, a qualitative description of the asymptotic dynamics of a class of non-tilted spatially homogeneous (SH) cosmologies, the so-called exceptional Bianchi cosmologies, which are of Bianchi type VI$_{-1/9}$. This class is of interest for two reasons. Firstly, it is generic within the class of non-tilted SH cosmologies, being of the same generality as the models of Bianchi types VIII and IX. Secondly, it is the SH limit of a generic class of spatially inhomogeneous $G_{2}$ cosmologies. Using the orthonormal frame formalism and Hubble-normalized variables, we show that the exceptional Bianchi cosmologies differ from the non-exceptional Bianchi cosmologies of type VI$_{h}$ in two significant ways. Firstly, the models exhibit an oscillatory approach to the initial singularity and hence are not asymptotically self-similar. Secondly, at late times, although the models are asymptotically self-similar, the future attractor for the vacuum-dominated models is the so-called Robinson-Trautman SH model instead of the vacuum SH plane wave models.

CONSTRUCTING AND DERIVING RECIPROCAL TRIGONOMETRIC RELATIONS: A FUNCTIONAL ANALYTIC APPROACH

PubMed Central

Ninness, Chris; Dixon, Mark; Barnes-Holmes, Dermot; Rehfeldt, Ruth Anne; Rumph, Robin; McCuller, Glen; Holland, James; Smith, Ronald; Ninness, Sharon K; McGinty, Jennifer

2009-01-01

Participants were pretrained and tested on mutually entailed trigonometric relations and combinatorially entailed relations as they pertained to positive and negative forms of sine, cosine, secant, and cosecant. Experiment 1 focused on training and testing transformations of these mathematical functions in terms of amplitude and frequency followed by tests of novel relations. Experiment 2 addressed training in accordance with frames of coordination (same as) and frames of opposition (reciprocal of) followed by more tests of novel relations. All assessments of derived and novel formula-to-graph relations, including reciprocal functions with diversified amplitude and frequency transformations, indicated that all 4 participants demonstrated substantial improvement in their ability to identify increasingly complex trigonometric formula-to-graph relations pertaining to same as and reciprocal of to establish mathematically complex repertoires. PMID:19949509

Initial conditions for dark soliton generation in normal-dispersion fiber lasers.

PubMed

Ge, Y Q; Luo, J L; Li, L; Jin, X X; Tang, D Y; Shen, D Y; Zhang, S M; Zhao, L M

2015-01-01

We report results of numerical simulations on the various initial conditions for dark soliton generation in an all-normal-dispersion fiber laser. All the dark solitons generated are odd dark solitons. Differently from the dark soliton generation in fibers, where an arbitrary dip could evolve into a dark soliton, it is found that the dark soliton can originate only from an initial dip with a certain parameter requirement. A bright pulse with either a hyperbolic secant square, Gaussian, or Lorentz profile can be developed into a dark soliton, provided that the parameters of the initial bright pulse are selected. Dark solitons can be generated in fiber lasers only if there is a phase jump, and this phase jump can be maintained and evolve to π during the pulse evolution.

Constructing and deriving reciprocal trigonometric relations: a functional analytic approach.

PubMed

Ninness, Chris; Dixon, Mark; Barnes-Holmes, Dermot; Rehfeldt, Ruth Anne; Rumph, Robin; McCuller, Glen; Holland, James; Smith, Ronald; Ninness, Sharon K; McGinty, Jennifer

2009-01-01

Participants were pretrained and tested on mutually entailed trigonometric relations and combinatorially entailed relations as they pertained to positive and negative forms of sine, cosine, secant, and cosecant. Experiment 1 focused on training and testing transformations of these mathematical functions in terms of amplitude and frequency followed by tests of novel relations. Experiment 2 addressed training in accordance with frames of coordination (same as) and frames of opposition (reciprocal of) followed by more tests of novel relations. All assessments of derived and novel formula-to-graph relations, including reciprocal functions with diversified amplitude and frequency transformations, indicated that all 4 participants demonstrated substantial improvement in their ability to identify increasingly complex trigonometric formula-to-graph relations pertaining to same as and reciprocal of to establish mathematically complex repertoires.

Mid-infrared supercontinuum generation in tapered As2S3 chalcogenide planar waveguide

NASA Astrophysics Data System (ADS)

Zhang, Xiang; Hu, Hongyu; Li, Wenbo; Dutta, Niloy K.

2016-10-01

We numerically demonstrate mid-infrared supercontinuum generation in a non-uniformly tapered chalcogenide planar waveguide. This planar rib waveguide of As2S3 glass on MgF2 is 2 cm long with increasing etch depth longitudinally to manage the total dispersion. This waveguide has zero dispersion at two wavelengths. The dispersion profile varies along the propagation distance, leading to continuous modification of the phase-matching condition for dispersive wave emission and enhancement of energy transfer efficiency between solitons and dispersive waves. Numerical simulations are conducted for secant input pulses at a wavelength of 1.55 μm with a width of 50 fs and peak power of 2 kW. Results show this proposed scheme significantly broadens the generated continuum, extending from ~1 to ~7 μm.

Flat band in disorder-driven non-Hermitian Weyl semimetals

NASA Astrophysics Data System (ADS)

Zyuzin, A. A.; Zyuzin, A. Yu.

2018-01-01

We study the interplay of disorder and band-structure topology in a Weyl semimetal with a tilted conical spectrum around the Weyl points. The spectrum of particles is given by the eigenvalues of a non-Hermitian matrix, which contains contributions from a Weyl Hamiltonian and complex self-energy due to electron elastic scattering on disorder. We find that the tilt-induced matrix structure of the self-energy gives rise to either a flat band or a nodal line segment at the interface of the electron and hole pockets in the bulk band structure of type-II Weyl semimetals depending on the Weyl cone inclination. For the tilt in a single direction in momentum space, each Weyl point expands into a flat band lying on the plane, which is transverse to the direction of the tilt. The spectrum of the flat band is fully imaginary and is separated from the in-plane dispersive part of the spectrum by the "exceptional nodal ring" where the matrix of the Green's function in momentum-frequency space is defective. The tilt in two directions might shrink a flat band into a nodal line segment with "exceptional edge points." We discuss the connection to the non-Hermitian topological theory.

Volume Segmentation and Ghost Particles

NASA Astrophysics Data System (ADS)

Ziskin, Isaac; Adrian, Ronald

2011-11-01

Volume Segmentation Tomographic PIV (VS-TPIV) is a type of tomographic PIV in which images of particles in a relatively thick volume are segmented into images on a set of much thinner volumes that may be approximated as planes, as in 2D planar PIV. The planes of images can be analysed by standard mono-PIV, and the volume of flow vectors can be recreated by assembling the planes of vectors. The interrogation process is similar to a Holographic PIV analysis, except that the planes of image data are extracted from two-dimensional camera images of the volume of particles instead of three-dimensional holographic images. Like the tomographic PIV method using the MART algorithm, Volume Segmentation requires at least two cameras and works best with three or four. Unlike the MART method, Volume Segmentation does not require reconstruction of individual particle images one pixel at a time and it does not require an iterative process, so it operates much faster. As in all tomographic reconstruction strategies, ambiguities known as ghost particles are produced in the segmentation process. The effect of these ghost particles on the PIV measurement is discussed. This research was supported by Contract 79419-001-09, Los Alamos National Laboratory.

Intervertebral anticollision constraints improve out-of-plane translation accuracy of a single-plane fluoroscopy-to-CT registration method for measuring spinal motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Cheng-Chung; Tsai, Tsung-Yuan; Hsu, Shih-Jung

2013-03-15

Purpose: The study aimed to propose a new single-plane fluoroscopy-to-CT registration method integrated with intervertebral anticollision constraints for measuring three-dimensional (3D) intervertebral kinematics of the spine; and to evaluate the performance of the method without anticollision and with three variations of the anticollision constraints via an in vitro experiment. Methods: The proposed fluoroscopy-to-CT registration approach, called the weighted edge-matching with anticollision (WEMAC) method, was based on the integration of geometrical anticollision constraints for adjacent vertebrae and the weighted edge-matching score (WEMS) method that matched the digitally reconstructed radiographs of the CT models of the vertebrae and the measured single-plane fluoroscopymore » images. Three variations of the anticollision constraints, namely, T-DOF, R-DOF, and A-DOF methods, were proposed. An in vitro experiment using four porcine cervical spines in different postures was performed to evaluate the performance of the WEMS and the WEMAC methods. Results: The WEMS method gave high precision and small bias in all components for both vertebral pose and intervertebral pose measurements, except for relatively large errors for the out-of-plane translation component. The WEMAC method successfully reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five degrees of freedom (DOF) more or less unaltered. The means (standard deviations) of the out-of-plane translational errors were less than -0.5 (0.6) and -0.3 (0.8) mm for the T-DOF method and the R-DOF method, respectively. Conclusions: The proposed single-plane fluoroscopy-to-CT registration method reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five DOF more or less unaltered. With the submillimeter and subdegree accuracy, the WEMAC method was considered accurate for measuring 3D intervertebral kinematics during various functional activities for research and clinical applications.« less

Explicit Computations of Instantons and Large Deviations in Beta-Plane Turbulence

NASA Astrophysics Data System (ADS)

Laurie, J.; Bouchet, F.; Zaboronski, O.

2012-12-01

We use a path integral formalism and instanton theory in order to make explicit analytical predictions about large deviations and rare events in beta-plane turbulence. The path integral formalism is a concise way to get large deviation results in dynamical systems forced by random noise. In the most simple cases, it leads to the same results as the Freidlin-Wentzell theory, but it has a wider range of applicability. This approach is however usually extremely limited, due to the complexity of the theoretical problems. As a consequence it provides explicit results in a fairly limited number of models, often extremely simple ones with only a few degrees of freedom. Few exception exist outside the realm of equilibrium statistical physics. We will show that the barotropic model of beta-plane turbulence is one of these non-equilibrium exceptions. We describe sets of explicit solutions to the instanton equation, and precise derivations of the action functional (or large deviation rate function). The reason why such exact computations are possible is related to the existence of hidden symmetries and conservation laws for the instanton dynamics. We outline several applications of this apporach. For instance, we compute explicitly the very low probability to observe flows with an energy much larger or smaller than the typical one. Moreover, we consider regimes for which the system has multiple attractors (corresponding to different numbers of alternating jets), and discuss the computation of transition probabilities between two such attractors. These extremely rare events are of the utmost importance as the dynamics undergo qualitative macroscopic changes during such transitions.

Molecular statics simulation of CdTe grain boundary structures and energetics using a bond-order potential

NASA Astrophysics Data System (ADS)

Stechmann, Guillaume; Zaefferer, Stefan; Raabe, Dierk

2018-06-01

The structure and energetics of coincidence site lattice grain boundaries (GB) in CdTe are investigated by mean of molecular statics simulations, using the Cd–Zn–Te bond-order potential (second iteration) developed by Ward et al (2012 Phys. Rev. B 86 245203; 2013 J. Mol. Modelling 19 5469–77). The effects of misorientation (Σ value) and interface plane are treated separately, complying with the critical need for full five-parameter characterization of GB. In addition, stoichiometric shifts, occurring between the inner interfaces and their adjacent atomic layers, are also predicted, revealing the energetic preference of Te-rich boundaries, opening opportunities for crystallography-based intrinsic interface doping. Our results also suggest that the intuitive assumption that Σ3 boundaries with low-indexed planes are more energetically favorable is often unfounded, except for coherent twins developing on {111} boundary planes. Therefore, Σ5, 7 or 9 boundaries, with lower interface energy than that of twin boundaries lying on different facets, are frequently encountered.

An efficient shutter-less non-uniformity correction method for infrared focal plane arrays

NASA Astrophysics Data System (ADS)

Huang, Xiyan; Sui, Xiubao; Zhao, Yao

2017-02-01

The non-uniformity response in infrared focal plane array (IRFPA) detectors has a bad effect on images with fixed pattern noise. At present, it is common to use shutter to prevent from radiation of target and to update the parameters of non-uniformity correction in the infrared imaging system. The use of shutter causes "freezing" image. And inevitably, there exists the problems of the instability and reliability of system, power consumption, and concealment of infrared detection. In this paper, we present an efficient shutter-less non-uniformity correction (NUC) method for infrared focal plane arrays. The infrared imaging system can use the data gaining in thermostat to calculate the incident infrared radiation by shell real-timely. And the primary output of detector except the shell radiation can be corrected by the gain coefficient. This method has been tested in real infrared imaging system, reaching high correction level, reducing fixed pattern noise, adapting wide temperature range.

The bending strength of tablets with a breaking line--Comparison of the results of an elastic and a "brittle cracking" finite element model with experimental findings.

PubMed

Podczeck, Fridrun; Newton, J Michael; Fromme, Paul

2015-11-10

The aim of this work was to ascertain the influence of the position of the breaking line of bevel-edged tablets in a three-point bending test. Two different brands of commercially available, flat-round, bevel-edged tablets with a single central breaking line were studied. Breaking line positions tested, relative to the upper loading roll, were 0°, 22.5°, 45°, 67.5° and 90°. The breaking line faced either up- or downwards during the test. The practical results were compared with FEM results simulating similar test configurations. Tablets failed mainly across the failure plane, resulting in two tablet halves. An exception to this was found for tablets where the breaking line faced down and was positioned at an angle of 22.5° relative to the loading plane. Here the crack followed the breaking line in the centre of the tablets and only diverged towards the loading plane position at the edges of the tablets. The breaking line facing upwards resulted in a significantly higher tensile strength of the tablets compared to it facing downwards. However, with one exception, the orientation of the breaking line relative to the loading plane appeared not to affect the tensile strength values. A fully elastic FEM model indicated that both the position of the breaking line relative to the loading plane and as to whether the breaking line faced up- or downwards during the bending test would result in considerably different failure loads during practical experiments. The results also suggested that regardless of the breaking line position, when it is facing down crack propagation should start at the outer edges propagating towards the midpoint of the discs until failure occurs. Failure should hence always result in equal tablet halves, whereby the failure plane should coincide with the loading plane. Neither predictions fully reflected the practical behaviour of the tablets. Using a brittle cracking FEM model significantly larger tensile stresses for tablets with the breaking line positioned downwards at 0° or 22.5° relative to the loading plane were still predicted, but the differences between model and experimental values was greatly reduced. The remaining differences are more likely due to the inadequacy of the equation available to calculate the experimental tensile strength values. This equation cannot account for the presence of a breaking line and overestimates the thickness of the loading plane by the depth of the breaking line when in 0° or 22.5° position. If the depth of the breaking line is taken into account, the model predictions and the experimental findings are comparable. Also, in the brittle cracking FEM simulations the predicted crack propagation patterns were similar to those found in the experiments, and the model stress distributions across the lower surfaces were much more homogeneous and streamlined parallel to the loading plane. The brittle cracking model hence reflected the practicalities of the bending test more closely. The findings suggested that with the breaking line facing down fracture should always start in the centre of a tablet at its lower surface, initiated by the breaking line. Due to simultaneous development of larger stresses along the y-axis the tablet should still break into two equal halves along the loading plane, unless the position of the breaking line relative to the loading plane was 22.5°. In this case the tablet would fail by a mixed process, whereby failure would occur mainly along the breaking line, but due to simultaneous crack formation at the lower surface close to the bevel edge parallel to the loading plane the final breaking pattern would deviate from the breaking line about half-way from its centre, as seen in the practical experiments. Copyright © 2015 Elsevier B.V. All rights reserved.

Strain distribution in an Si single crystal measured by interference fringes of X-ray mirage diffraction

PubMed Central

Jongsukswat, Sukswat; Fukamachi, Tomoe; Ju, Dongying; Negishi, Riichirou; Hirano, Keiichi; Kawamura, Takaaki

2013-01-01

In X-ray interference fringes accompanied by mirage diffraction, variations have been observed in the spacing and position of the fringes from a plane-parallel Si single crystal fixed at one end as a function of distance from the incident plane of the X-rays to the free crystal end. The variations can be explained by distortion of the sample crystal due to gravity. From the variations and positions of the fringes, the strain gradient of the crystal has been determined. The distribution of the observed strain agrees with that expected from rod theory except for residual strain. When the distortion is large, the observed strain distribution does not agree with that expected from rod theory. PMID:24068841

T-Duality for Orientifolds and Twisted KR-Theory

NASA Astrophysics Data System (ADS)

Doran, Charles; Méndez-Diez, Stefan; Rosenberg, Jonathan

2014-08-01

D-brane charges in orientifold string theories are classified by the KR-theory of Atiyah. However, this is assuming that all O-planes have the same sign. When there are O-planes of different signs, physics demands a "KR-theory with a sign choice" which up until now has not been studied by mathematicians (with the unique exception of Moutuou, who did not have a specific application in mind). We give a definition of this theory and compute it for orientifold theories compactified on S 1 and T 2. We also explain how and why additional "twisting" is implemented. We show that our results satisfy all possible T-duality relationships for orientifold string theories on elliptic curves, which will be studied further in subsequent work.

Preliminary study of tug-glider freight systems utilizing a Boeing 747 as the tug

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heyson, H.H.; Foss, W.E. Jr

1977-02-01

Performance of the tug-glider system was severely limited by ground run. In most cases studied, additional engines were necessary. Except at short ranges for which additional payload were carried in the tow plane, the productivity of the basic aircraft was degraded by a reduction in cruise speed necessitated by the glider drag. Excessive aspect ratios did not improve system performance because of the increase in glider wing weight. Powered gliders using a tow plane only for takeoff and climb had the potential for a major reduction in fuel consumption. Uncertainty of restrictive regulatory action and the apparently increased airborne investmentmore » per unit productivity are obstacles to commercial development.« less

A joint program with Japanese investigators to map carbon 2 line emission from the galaxy

NASA Technical Reports Server (NTRS)

Low, Frank J.; Nishimura, Tetsuo

1993-01-01

A large portion of the inner galactic plane has been mapped in the far-infrared (C II) line using a balloon-borne survey instrument. Complete coverage is reported from 25 degrees north to 80 degrees south of the galactic center and extending a few degrees on each side of the plane. Effective resolution is 14.1 acrmin (FWHM) and contour levels begin at 2 E -5 ergs/(s x sq. cm x ster). When compared with 100 micron dust emission observed by IRAS the (C II) appears well correlated with the dust emission except for a 10 degree region centered on the galactic center where emission from the gas is much weaker than that from the dust.

Evaluation of single crystal LaB6 cathodes for use in a high frequency backward wave oscillator tube

NASA Technical Reports Server (NTRS)

Swanson, L. W.; Davis, P. R.; Schwind, G. A.

1984-01-01

The results of thermionic emission and evaporation studies of single crystal LaB6 cathodes are given. A comparison between the (100), (210) and (310) crystal planes shows the (310) and (210) planes to possess a work function approx 0.2 eV lower than (100). This translates into a significant increase in current density, J, at a specified temperature. Comparison with a state-of-the-art impregnated dispenser cathode shows that LaB6 (310) is a superior cathode in nearly all respects except operating temperature at j 10 A/sq cm. The 1600 K thermionic and room temperature retarding potential work functions for LaB6 (310) are 2.42 and 2.50 respectively.

Experimental investigation of time dependent behavior of welded Topopah Spring Tuff

NASA Astrophysics Data System (ADS)

Ma, Lumin

Four types of laboratory tests have been performed. Specimens were attained from four lithophysal zones of the welded Topopah Spring Tuff unit at Yucca Mountain, Nevada: upper lithophysal, middle nonlithophysal, lower lithophysal and lower nonlithophysal zones. Two types of tests are conducted to study time-dependent behavior: constant strain rate and creep tests. Sixty-five specimens from the middle nonlithophysal zone were tested at six strain rates: 10-2, 10-4, 10-5, 10-6, 10-7, and 10-8 s-1. Test durations range from 2 seconds to 7 days. Fourteen specimens from middle nonlithophysal, lower lithophysal and lower nonlithophysal zones are creep tested by incremental stepwise loading. All the tests are conducted under uniaxial compression at room temperature and humidity. Specimens exhibit extremely brittle fracture and fail by axial splitting, and show very little dilatancy if any. It is assumed that microfracturing dominates the inelastic deformation and failure of the tuff. Nonlinear regression is applied to the results of the constant strain rate tests to estimate the relations between peak strength, peak axial strain, secant modulus and strain rate. All three these parameters decrease with a decrease of strain rate and follow power functions: sigmapeak = 271.37 3˙0.0212 0.0212, epsilonpeak = 0.006 3˙0.0083 , ES = 41985.4 3˙0.015 . Secant modulus is introduced mainly as a tool to analyze strain rate dependent axial strain. Two threshold stresses define creep behavior. Below about 50% of peak strength, a specimen does not creep. Above about 94% of peak strength, a specimen creeps at an accelerating rate. Between the two threshold stresses, a power law relates strain rate and stress. One hundred fifty-eight Brazilian (Indirect tensile splitting) tests have been performed at six different constant strain rates. Nineteen lithophysal specimens were tested in uniaxial compression to study their fracture pattern. These specimens have a far less brittle failure mode. They slowly crumble, collapse, and maintain considerable relative strength beyond the peak. Due to the presence of multiple relatively large lithophysal cavities, they are far weaker and softer than the nonlithophysal specimens.

Delineation of fractures, foliation, and groundwater-flow zones of the bedrock at the Harlem River Tunnel in northern New York County, New York

USGS Publications Warehouse

Stumm, Frederick; Chu, Anthony; Joesten, Peter K.; Noll, Michael L.; Como, Michael D.

2013-01-01

Advanced borehole-geophysical methods were used to investigate the hydrogeology of the crystalline bedrock in 36 boreholes on the northernmost part of New York County, New York, for the construction of a utilities tunnel beneath the Harlem River. The borehole-logging techniques were used to delineate bedrock fractures, foliation, and groundwater-flow zones in test boreholes at the site. Fracture indexes of the deep boreholes ranged from 0.65 to 0.76 per foot. Most of the fracture populations had either northwest to southwest or east to southeast dip azimuths with moderate dip angles. The mean foliation dip azimuth ranged from 100º to 124º southeast with dip angles of 52º to 60º. Groundwater appears to flow through an interconnected network of fractures that are affected by tidal variations from the nearby Harlem River and tunnel construction dewatering operations. The transmissivities of the 3 boreholes tested (USGS-1, USGS-3, and USGS-4), calculated from specific capacity data, were 2, 48, and 30 feet squared per day (ft2/d), respectively. The highest transmissivities were observed in wells north and west of the secant ring. Three borehole-radar velocity tomograms were collected. In the USGS-1 and USGS-4 velocity tomogram there are two areas of low radar velocity. The first is at the top of the tomogram and runs from 105 ft below land surface (BLS) at USGS-4 and extends to 125 ft BLS at USGS-1, the second area is centered at a depth of 150 ft BLS at USGS-1 and 135 to 150 ft BLS at USGS-4. Field measurements of specific conductance of 14 boreholes under ambient conditions at the site indicate an increase in conductivity toward the southwest part of the site (nearest the Harlem River). Specific conductance ranged from 107 microsiemens per centimeter (μS/cm) (borehole 63C) to 11,000 μS/cm (borehole 79B). The secant boreholes had the highest specific conductance.

Temperature Dependence of Phonons in Pyrolitic Graphite

DOE R&D Accomplishments Database

Brockhouse, B. N.; Shirane, G.

1977-01-01

Dispersion curves for longitudinal and transverse phonons propagating along and near the c-axis in pyrolitic graphite at temperatures between 4?K and 1500?C have been measured by neutron spectroscopy. The observed frequencies decrease markedly with increasing temperature (except for the transverse optical ''rippling'' modes in the hexagonal planes). The neutron groups show interesting asymmetrical broadening ascribed to interference between one phonon and many phonon processes.

Modelling of the UV Index on vertical and 40° tilted planes for different orientations.

PubMed

Serrano, D; Marín, M J; Utrillas, M P; Tena, F; Martínez-Lozano, J A

2012-02-01

In this study, estimated data of the UV Index on vertical planes are presented for the latitude of Valencia, Spain. For that purpose, the UVER values have been generated on vertical planes by means of four different geometrical models a) isotropic, b) Perez, c) Gueymard, d) Muneer, based on values of the global horizontal UVER and the diffuse horizontal UVER, measured experimentally. The UVER values, obtained by any model, overestimate the experimental values for all orientations, with the exception of the Perez model for the East plane. The results show statistical values of the MAD parameter (Mean Absolute Deviation) between 10% and 25%, the Perez model being the one that obtained a lower MAD for all levels. As for the statistic RMSD parameter (Root Mean Square Deviation), the results show values between 17% and 32%, and again the Perez model provides the best results in all vertical planes. The difference between the estimated UV Index and the experimental UV Index, for vertical and 40° tilted planes, was also calculated. 40° is an angle close to the latitude of Burjassot, Valencia, (39.5°), which, according to various studies, is the optimum angle to capture maximum radiation on tilted planes. We conclude that the models provide a good estimate of the UV Index, as they coincide or differ in one unit compared to the experimental values in 99% of cases, and this is valid for all orientations. Finally, we examined the relation between the UV Index on vertical and 40° tilted planes, both the experimental and estimated by the Perez model, and the experimental UV Index on a horizontal plane at 12 GMT. Based on the results, we can conclude that it is possible to estimate with a good approximation the UV Index on vertical and 40° tilted planes in different directions on the basis of the experimental horizontal UVI value, thus justifying the interest of this study. This journal is © The Royal Society of Chemistry and Owner Societies 2012

Landsat 9 OLI 2 focal plane subsystem: design, performance, and status

NASA Astrophysics Data System (ADS)

Malone, Kevin J.; Schrein, Ronald J.; Bradley, M. Scott; Irwin, Ronda; Berdanier, Barry; Donley, Eric

2017-09-01

The Landsat 9 mission will continue the legacy of Earth remote sensing that started in 1972. The Operational Land Imager 2 (OLI 2) is one of two instruments on the Landsat 9 satellite. The OLI 2 instrument is essentially a copy of the OLI instrument flying on Landsat 8. A key element of the OLI 2 instrument is the focal plane subsystem, or FPS, which consists of the focal plane array (FPA), the focal plane electronics (FPE) box, and low-thermal conductivity cables. This paper presents design details of the OLI 2 FPS. The FPA contains 14 critically-aligned focal plane modules (FPM). Each module contains 6 visible/near-IR (VNIR) detector arrays and three short-wave infrared (SWIR) arrays. A complex multi-spectral optical filter is contained in each module. Redundant pixels for each array provide exceptional operability. Spare detector modules from OLI were recharacterized after six years of storage. Radiometric test results are presented and compared with data recorded in 2010. Thermal, optical, mechanical and structural features of the FPA will be described. Special attention is paid to the thermal design of the FPA since thermal stability is crucial to ensuring low-noise and low-drift operation of the detectors which operate at -63°C. The OLI 2 FPE provides power, timing, and control to the focal plane modules. It also digitizes the video data and formats it for the solid-state recorder. Design improvements to the FPA-FPE cables will be discussed and characterization data will be presented. The paper will conclude with the status of the flight hardware assembly and testing.

Lattice Boltzmann simulation of shear-induced particle migration in plane Couette-Poiseuille flow: Local ordering of suspension

NASA Astrophysics Data System (ADS)

Chun, Byoungjin; Kwon, Ilyoung; Jung, Hyun Wook; Hyun, Jae Chun

2017-12-01

The shear-induced migration of concentrated non-Brownian monodisperse suspensions in combined plane Couette-Poiseuille (C-P) flows is studied using a lattice Boltzmann simulation. The simulations are mainly performed for a particle volume fraction of ϕbulk = 0.4 and H/a = 44.3, 23.3, where H and a denote the channel height and radius of suspended particles, respectively. The simulation method is validated in two simple flows, plane Poiseuille and plane Couette flows. In the Poiseuille flow, particles migrate to the mid-plane of the channel where the local concentration is close to the limit of random-close-packing, and a random structure is also observed at the plane. In the Couette flow, the particle distribution remains in the initial uniform distribution. In the combined C-P flows, the behaviors of migration are categorized into three groups, namely, Poiseuille-dominant, Couette-dominant, and intermediate regimes, based on the value of a characteristic force, G, where G denotes the relative magnitude of the body force (P) against the wall-driving force (C). With respect to the Poiseuille-dominant regime, the location of the maximum concentration is shifted from the mid-plane to the lower wall moving in the same direction as the external body force, when G decreases. With respect to the Couette-dominant regime, the behavior is similar to that of a simple shear flow with the exception that a slightly higher concentration of particles is observed near the lower wall. However, with respect to the intermediate value of G, several layers of highly ordered particles are unexpectedly observed near the lower wall where the plane of maximum concentration is located. The locally ordered structure is mainly due to the lateral migration of particles and wall confinement. The suspended particles migrate toward a vanishingly small shear rate at the wall, and they are consequently layered into highly ordered two-dimensional structures at the high local volume fraction.

A concept to transfer a therapeutic splint position into permanent occlusion with a customized lingual appliance.

PubMed

Sachse, Tina; Schwestka-Polly, Rainer; Flieger, Stefanie; Wiechmann, Dirk

2012-05-21

The role of occlusion concerning temporomandibular disorder is still unclear but seems to be the only component of the stomathognathic system dentists are able to change morphologically. The aim of the paper is to describe the orthodontist's approach for transferring and maintaining a therapeutic splint position into permanent occlusion using a fully customized lingual appliance. Fixed acrylic bite planes on lower molars were used to maintain a symptom-free condyle position prior to orthodontic treatment. Silicone impressions of the arches including the fixed bite planes were used for the Incognito laboratory procedure. Two digital setups were made. One setup represents the target occlusion. A second setup including the bite planes was used to fabricate an additional set of lower molar brackets. In the leveling stage all teeth except the lower molars were settled to maintain the therapeutic condyle position. Finally, the fixed bite planes were stepwise removed and molar brackets were replaced to establish the permanent occlusion planned with the first setup. The advantage of an individual lingual appliance consists in the high level of congruence between the fabricated setups and the final clinical result. Both the individual scope for design and the precision of the appliance were vitally important in the treatment of a patient with a functional disorder of the masticatory system.

Displacement-length scaling of brittle faults in ductile shear.

PubMed

Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

2011-11-01

Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement-distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow.

Displacement–length scaling of brittle faults in ductile shear

PubMed Central

Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

2011-01-01

Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement–distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow. PMID:26806996

Magnetic resonance imaging at a high field strength of ventricular septal defects in infants.

PubMed

Baker, E J; Ayton, V; Smith, M A; Parsons, J M; Ladusans, E J; Anderson, R H; Maisey, M N; Tynan, M; Fagg, N L; Deverall, P B

1989-10-01

Magnetic resonance imaging at a high field strength has potential benefits for the study of the heart in infants, which is when most congenital heart disease presents. Seventeen infants with various anatomical types of ventricular septal defect were studied by this technique. Good quality, high resolution, images were obtained in every case. There were no major practical problems. The morphology of the defects in all 17 hearts was displayed in great detail. In some instances, the interpretation of the images resembled that of equivalent images from cross sectional echocardiography. But this new technique allowed imaging in planes that cannot be obtained by echocardiography. One particularly valuable plane gave a face on view of the inlet and trabecular components of the septum. This allowed very precise localisation of defects in these areas. The relation between the defects and the atrioventricular and arterial valves was exceptionally well shown in various different imaging planes. One patient in the series had multiple trabecular defects that were clearly shown. Magnetic resonance imaging gives detailed morphological information about ventricular septal defects.

Tricuspid annular plane systolic excursion is preserved in young patients with pulmonary hypertension except when associated with repaired congenital heart disease.

PubMed

Hauck, Amanda; Guo, Ruixin; Ivy, D Dunbar; Younoszai, Adel

2017-04-01

Tricuspid annular plane systolic excursion (TAPSE) is a measure of right ventricular (RV) longitudinal function that correlates with functional status and mortality in adults with pulmonary hypertension (PH). The diagnostic and predictive value of TAPSE in children with PH has not been fully examined. We aimed to define TAPSE across aetiologies of paediatric PH and assess the correlation between TAPSE and measures of disease severity. TAPSE measurements were obtained in 84 children and young adults undergoing treatment for PH and 315 healthy children to establish z-scores at moderate altitude for comparison. The relationships between TAPSE and echocardiographic, biomarker, and functional measures of disease severity between aetiologies were assessed. TAPSE z-scores in PH patients with congenital heart disease (CHD) repaired with open cardiac surgery (n = 20, mean -2.73) were significantly decreased compared with normal children and patients with other aetiologies of PH (P < 0.001) but did not reflect poorer clinical status. TAPSE z-scores in children with idiopathic PH (n = 29, -0.41), unrepaired CHD (n = 11, -0.1), and PH related to systemic disease (n = 14, -0.39) were not different from normal. TAPSE correlated modestly with brain natriuretic peptide, echocardiographic function parameters, and functional class except in patients with repaired CHD. Children with PH maintain normal TAPSE values early except when associated with repaired CHD. Superior RV adaptation to high afterload in children compared with adults may account for this finding. Reduced TAPSE after repair of CHD does not correlate with functional status and may reflect post-operative changes rather than poor function primarily due to PH. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

The ground vortex flow field associated with a jet in a cross flow impinging on a ground plane for uniform and annular turbulent axisymmetric jets. M.S. Thesis

NASA Technical Reports Server (NTRS)

Cavage, William M.; Kuhlman, John M.

1993-01-01

An experimental study was conducted of the impingement of a single circular jet on a ground plane in a cross flow. This geometry is a simplified model of the interaction of propulsive jet exhaust from a V/STOL aircraft with the ground in forward flight. Jets were oriented normal to the cross flow and ground plane. Jet size, cross flow-to-jet velocity ratio, ground plane-to-jet board spacing, and jet exit turbulence level and mean velocity profile shape were all varied to determine their effects on the size of the ground vortex interaction region which forms on the ground plane, using smoke injection into the jet. Three component laser Doppler velocimeter measurements were made with a commercial three color system for the case of a uniform jet with exit spacing equal to 5.5 diameters and cross flow-to-jet velocity ratio equal to 0.11. The flow visualization data compared well for equivalent runs of the same nondimensional jet exit spacing and the same velocity ratio for different diameter nozzles, except at very low velocity ratios and for the larger nozzle, where tunnel blockage became significant. Variation of observed ground vortex size with cross flow-to-jet velocity ratio was consistent with previous studies. Observed effects of jet size and ground plane-to-jet board spacing were relatively small. Jet exit turbulence level effects were also small. However, an annular jet with a low velocity central core was found to have a significantly smaller ground vortex than an equivalent uniform jet at the same values of cross flow-to-jet velocity ratio and jet exit-to-ground plane spacing. This may suggest a means of altering ground vortex behavior somewhat, and points out the importance of proper simulation of jet exit velocity conditions. LV data indicated unsteady turbulence levels in the ground vortex in excess of 70 percent.

A general purpose wideband optical spatial frequency spectrum analyzer

NASA Technical Reports Server (NTRS)

Ballard, G. S.; Mellor, F. A.

1972-01-01

The light scattered at various angles by a transparent media is studied. An example of these applications is the optical Fourier spectrum measurement resulting from various spatial frequencies which were recorded on a photographic emulsion. A method for obtaining these measurements consists of illuminating the test object with parallel monochromatic light. A stationary lens, placed in the resulting wavefield at a distance of one focal length from the object, will focus parallel waves emanating from the test object at a point lying in the focal plane of the lens. A light detector with a small filtering aperture is then used to measure the intensity variation of the light in the focal or transform plane of the lens. Such measurements require the use of a lens which is highly corrected for all of the common aberrations except chromatic aberration.

[Efficient imaging of elbow injuries in children and adolescents].

PubMed

Kraus, R; Berthold, L D; von Laer, L

2007-01-01

The purpose of imaging of the elbow region in children after acute trauma is the diagnosis of injuries that require further treatment. Basic diagnostic consists of standard X-rays of the elbow in two planes. Exceptions can be made in the case of nursemaid's elbow lesion (subluxation of the radial head; pronation douloureuse; Chassaignac lesion) with unambiguous mechanism of the trauma where no X-ray imaging is needed and in heavily dislocated fractures for which one plane can be sufficient. X-ray imaging of the uninjured side is obsolete. Follow-up X-ray imaging is only allowed if consequences for the further treatment are expected. Ultrasound may partially replace X-rays in the future if further standardization of this technique can be achieved. MRI provides additional information in acute trauma which, however, remains currently without consequences for the further treatment strategy.

NMR Studies of Low-Gamma Nuclei in Solids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wasylishen, Roderick E.; Forgeron, Michelle A.; Siegel, Renee

2006-07-24

Over the past five years we have devoted considerable time to solid-state NMR investigaitons of nuclei, which are traditionally known as "difficult" because of their small magnetic moments. These include quadrupolar nuclei such as 35Cl, 53 Cr, 91Zr, 95Mo, 99Ru, 131 Xe, as well as spin-1/2 nuclei such as 109Ag. While NMR studies of such isotopes remain challenging, the use of moderate to high magnetic field strengths together with a variety of enhancement techniques is leading to many interesting applications. In this talk some of our successes in studying these isotopes will be presented. For example, we will present preliminarymore » results of 131Xe NMR studies of solid sodium perxenate, as well as 109Ag NMR studies of silver dialkylphosphites. Our experience using population enhancement techniques that utilize hyperbolic secant pulses will also be discussed.« less

Computational modes and the Machenauer N.L.N.M.I. of the GLAS 4th order model. [NonLinear Normal Mode Initialization in numerical weather forecasting

NASA Technical Reports Server (NTRS)

Navon, I. M.; Bloom, S.; Takacs, L. L.

1985-01-01

An attempt was made to use the GLAS global 4th order shallow water equations to perform a Machenhauer nonlinear normal mode initialization (NLNMI) for the external vertical mode. A new algorithm was defined for identifying and filtering out computational modes which affect the convergence of the Machenhauer iterative procedure. The computational modes and zonal waves were linearly initialized and gravitational modes were nonlinearly initialized. The Machenhauer NLNMI was insensitive to the absence of high zonal wave numbers. The effects of the Machenhauer scheme were evaluated by performing 24 hr integrations with nondissipative and dissipative explicit time integration models. The NLNMI was found to be inferior to the Rasch (1984) pseudo-secant technique for obtaining convergence when the time scales of nonlinear forcing were much smaller than the time scales expected from the natural frequency of the mode.

Evaluation of statistical distributions to analyze the pollution of Cd and Pb in urban runoff.

PubMed

Toranjian, Amin; Marofi, Safar

2017-05-01

Heavy metal pollution in urban runoff causes severe environmental damage. Identification of these pollutants and their statistical analysis is necessary to provide management guidelines. In this study, 45 continuous probability distribution functions were selected to fit the Cd and Pb data in the runoff events of an urban area during October 2014-May 2015. The sampling was conducted from the outlet of the city basin during seven precipitation events. For evaluation and ranking of the functions, we used the goodness of fit Kolmogorov-Smirnov and Anderson-Darling tests. The results of Cd analysis showed that Hyperbolic Secant, Wakeby and Log-Pearson 3 are suitable for frequency analysis of the event mean concentration (EMC), the instantaneous concentration series (ICS) and instantaneous concentration of each event (ICEE), respectively. In addition, the LP3, Wakeby and Generalized Extreme Value functions were chosen for the EMC, ICS and ICEE related to Pb contamination.

The time-dependence of exchange-induced relaxation during modulated radio frequency pulses.

PubMed

Sorce, Dennis J; Michaeli, Shalom; Garwood, Michael

2006-03-01

The problem of the relaxation of identical spins 1/2 induced by chemical exchange between spins with different chemical shifts in the presence of time-dependent RF irradiation (in the first rotating frame) is considered for the fast exchange regime. The solution for the time evolution under the chemical exchange Hamiltonian in the tilted doubly rotating frame (TDRF) is presented. Detailed derivation is specified to the case of a two-site chemical exchange system with complete randomization between jumps of the exchanging spins. The derived theory can be applied to describe the modulation of the chemical exchange relaxation rate constants when using a train of adiabatic pulses, such as the hyperbolic secant pulse. Theory presented is valid for quantification of the exchange-induced time-dependent rotating frame longitudinal T1rho,ex and transverse T2rho,ex relaxations in the fast chemical exchange regime.

Geometric descriptions of entangled states by auxiliary varieties

NASA Astrophysics Data System (ADS)

Holweck, Frédéric; Luque, Jean-Gabriel; Thibon, Jean-Yves

2012-10-01

The aim of the paper is to propose geometric descriptions of multipartite entangled states using algebraic geometry. In the context of this paper, geometric means each stratum of the Hilbert space, corresponding to an entangled state, is an open subset of an algebraic variety built by classical geometric constructions (tangent lines, secant lines) from the set of separable states. In this setting, we describe well-known classifications of multipartite entanglement such as 2 × 2 × (n + 1), for n ⩾ 1, quantum systems and a new description with the 2 × 3 × 3 quantum system. Our results complete the approach of Miyake and make stronger connections with recent work of algebraic geometers. Moreover, for the quantum systems detailed in this paper, we propose an algorithm, based on the classical theory of invariants, to decide to which subvariety of the Hilbert space a given state belongs.

Effect of hemodynamics on outcome of subtotally occluded paraclinoid aneurysms after stent-assisted coil embolization.

PubMed

Liu, Jian; Jing, Linkai; Wang, Chao; Paliwal, Nikhil; Wang, Shengzhang; Zhang, Ying; Xiang, Jianping; Siddiqui, Adnan H; Meng, Hui; Yang, Xinjian

2016-11-01

Endovascular treatment of paraclinoid aneurysms is preferred in clinical practice. Flow alterations caused by stents and coils may affect treatment outcome. To assess hemodynamic changes following stent-assisted coil embolization (SACE) in subtotally embolized paraclinoid aneurysms with residual necks that were predisposed to recanalization. We studied 27 paraclinoid aneurysms (seven recanalized and 20 stable) treated with coils and Enterprise stents. Computational fluid dynamic simulations were performed on patient-specific aneurysm geometries using virtual stenting and porous media technology. After stent placement in 27 cases, aneurysm flow velocity decreased significantly, the reduction gradually increasing from the neck plane (11.9%), to the residual neck (12.3%), to the aneurysm dome (16.3%). Subsequent coil embolization was performed after stent placement and the hemodynamic factors decreased further and significantly at all aneurysm regions except the neck plane. In a comparison of recanalized and stable cases, univariate analysis showed no significant differences in any parameter before treatment. After stent-assisted coiling, only the reduction in area-averaged velocity at the neck plane differed significantly between recanalized (8.1%) and stable cases (20.5%) (p=0.016). Aneurysm flow velocity can be significantly decreased by stent placement and coil embolization. However, hemodynamics at the aneurysm neck plane is less sensitive to coils. Significant reduction in flow velocity at the neck plane may be an important factor in preventing recanalization of paraclinoid aneurysms after subtotal SACE. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Reflection coefficient of qP, qS and SH at a plane boundary between viscoelastic TTI media

NASA Astrophysics Data System (ADS)

Wang, Hongwei; Peng, Suping

2016-01-01

This paper introduces a calculation method for the effective elastic stiffness tensor matrix of the viscous-elastic TTI medium based on the Chapman theory. We then obtain the phase velocity formula and seismic wave polarization formula of the viscous-elastic TTI medium, by solving the Christoffel equation; solve the phase angle of reflection and transmission wave through the numerical method in accordance with the wave slowness ellipsoid; on the basis of this assumption, and assuming that qP, qS and SH waves occurred simultaneously at the viscous-elastic anisotropic interface, establish the sixth-order Zoeppritz equation in accordance with the boundary conditions; establish the models for the upper and lower media which are viscous-elastic HTI, TTI, etc., on the basis of the sixth-order Zoeppritz equation; and study the impact of fracture dip angle, azimuth angle and frequency on the reflection coefficient. From this we obtain the following conclusions: the reflection coefficient can identify the fracture strike and dip when any information pertaining to the media is unknown; dispersion phenomenon is obvious on the axial plane of symmetry and weakened in the plane vertical to the axial plane of symmetry; the vertical-incidence longitudinal wave can stimulate the qS wave when the dip angle is not 0° or 90° under the condition of coincidence between the symmetry planes of the upper and lower media; when the symmetry planes of the upper and lower media do not coincide and the dip angle is not 0° or 90°, then the vertical-incidence qP will stimulate the qS and SH waves at the same time; the dip angle can cause the reflection coefficient curve to have a more obvious dispersion phenomenon, while the included angle between the symmetry planes of the upper and lower media will weaken the dispersion except SH; and the intercept of reflection coefficient is affected by the fracture dip and included angle between the symmetry planes of the upper and lower media.

Containerless crystallization of silicon

NASA Astrophysics Data System (ADS)

Kuribayashi, K.; Aoyama, T.

2002-04-01

Crystallization from undercooled melt of silicon was carried out by means of electro-magnetic levitation method under controlled undercooling. The measured growth rate vs. undercooling was categorized into three regions, I, II and III, respectively, from the point of the interface morphology. Thin plate crystals whose interface consisted of both faceted (1 1 1) plane and wavy edge plane like saw-tooth were observed in the region I where the undercooling is less than 100 K. The growth rate of the wavy edge plane was well described by the dendrite growth model. The morphology of growing crystals was abruptly changed to faceted dendrite in the region II, though there was no abrupt change in the growth rate. Seeding at temperatures in the region I changes the drop to a mono-crystalline sphere, if the growth rate along the normal direction of the thin plate crystal is controlled by step-wise growth on the faceted plane. Actually, the sample of 5 mm in diameter seeded at undercooling of 26 K was a quasi-single crystal with large grain, except for a small area where twinning and cracking are observed. The result suggests that the single crystal could be grown, if a smaller sample, 1 or 2 mm in diameter, that is difficult to be levitated by electro-magnetic force were processed with other methods such as free fall in a drop tube.

Packaging printed circuit boards: A production application of interactive graphics

NASA Technical Reports Server (NTRS)

Perrill, W. A.

1975-01-01

The structure and use of an Interactive Graphics Packaging Program (IGPP), conceived to apply computer graphics to the design of packaging electronic circuits onto printed circuit boards (PCB), were described. The intent was to combine the data storage and manipulative power of the computer with the imaginative, intuitive power of a human designer. The hardware includes a CDC 6400 computer and two CDC 777 terminals with CRT screens, light pens, and keyboards. The program is written in FORTRAN 4 extended with the exception of a few functions coded in COMPASS (assembly language). The IGPP performs four major functions for the designer: (1) data input and display, (2) component placement (automatic or manual), (3) conductor path routing (automatic or manual), and (4) data output. The most complex PCB packaged to date measured 16.5 cm by 19 cm and contained 380 components, two layers of ground planes and four layers of conductors mixed with ground planes.

Fourier transform digital holographic adaptive optics imaging system

PubMed Central

Liu, Changgeng; Yu, Xiao; Kim, Myung K.

2013-01-01

A Fourier transform digital holographic adaptive optics imaging system and its basic principles are proposed. The CCD is put at the exact Fourier transform plane of the pupil of the eye lens. The spherical curvature introduced by the optics except the eye lens itself is eliminated. The CCD is also at image plane of the target. The point-spread function of the system is directly recorded, making it easier to determine the correct guide-star hologram. Also, the light signal will be stronger at the CCD, especially for phase-aberration sensing. Numerical propagation is avoided. The sensor aperture has nothing to do with the resolution and the possibility of using low coherence or incoherent illumination is opened. The system becomes more efficient and flexible. Although it is intended for ophthalmic use, it also shows potential application in microscopy. The robustness and feasibility of this compact system are demonstrated by simulations and experiments using scattering objects. PMID:23262541

Texture Development and Material Flow Behavior During Refill Friction Stir Spot Welding of AlMgSc

NASA Astrophysics Data System (ADS)

Shen, Junjun; Lage, Sara B. M.; Suhuddin, Uceu F. H.; Bolfarini, Claudemiro; dos Santos, Jorge F.

2018-01-01

The microstructural evolution during refill friction stir spot welding of an AlMgSc alloy was studied. The primary texture that developed in all regions, with the exception of the weld center, was determined to be 〈110〉 fibers and interpreted as a simple shear texture with the 〈110〉 direction aligned with the shear direction. The material flow is mainly driven by two components: the simple shear acting on the horizontal plane causing an inward-directed spiral flow and the extrusion acting on the vertical plane causing an upward-directed or downward-directed flow. Under such a complex material flow, the weld center, which is subjected to minimal local strain, is the least recrystallized. In addition to the geometric effects of strain and grain subdivision, thermally activated high-angle grain boundary migration, particularly continuous dynamic recrystallization, drives the formation of refined grains in the stirred zone.

Electromagnetic radiation in a semi-compact space

NASA Astrophysics Data System (ADS)

Iso, Satoshi; Kitazawa, Noriaki; Yokoo, Sumito

2018-02-01

In this note, we investigate the electromagnetic radiation emitted from a revolving point charge in a compact space. If the point charge is circulating with an angular frequency ω0 on the (x , y)-plane at z = 0 with boundary conditions, x ∼ x + 2 πR and y ∼ y + 2 πR, it emits radiation into the z-direction of z ∈ [ - ∞ , + ∞ ]. We find that the radiation shows discontinuities as a function of ω0 R at which a new propagating mode with a different Fourier component appears. For a small radius limit ω0 R ≪ 1, all the Fourier modes except the zero mode on (x , y)-plane are killed, but an effect of squeezing the electric field totally enhances the radiation. In the large volume limit ω0 R → ∞, the energy flux of the radiation reduces to the expected Larmor formula.

Web flexibility and I-beam torsional oscillation

NASA Astrophysics Data System (ADS)

Stephen, N. G.; Wang, P. J.

1986-08-01

Two recent theories on torsional oscillation of general doubly-symmetric non-circular cross-section beams incorporate a second order effect, that of in-plane shear deformation involving a change in cross-sectional shape, and are found to give excellent agreement with exact results for an elliptical section rod. For "technical" torsional oscillation theories of I-section beams this in-plane shear has previously been considered within the flanges only; in the present work the greater effect of shear distortion of the web is included, having previously been considered only in static analysis. The theory predicts three modes of wave propagation, one of which is essentially torsional in character; a second mode may be identified with predominatly flange bending according to the second branch of Timoshenko beam theory whilst a new mode involves individual flange torsion with asymmetric web deformation, and has the lowest phase velocity except at the longest wavelength. An alternative symmetric web deformation is also considered.

Constraints on Einstein-aether theory after GW170817

NASA Astrophysics Data System (ADS)

Oost, Jacob; Mukohyama, Shinji; Wang, Anzhong

2018-06-01

In this paper, we carry out a systematic analysis of the theoretical and observational constraints on the dimensionless coupling constants ci (i =1 , 2, 3, 4) of the Einstein-aether theory, taking into account the events GW170817 and GRB 170817A. The combination of these events restricts the deviation of the speed cT of the spin-2 graviton to the range, -3 ×10-15

On the linear stability of compressible plane Couette flow

NASA Technical Reports Server (NTRS)

Duck, Peter W.; Erlebacher, Gordon; Hussaini, M. Yousuff

1991-01-01

The linear stability of compressible plane Couette flow is investigated. The correct and proper basic velocity and temperature distributions are perturbed by a small amplitude normal mode disturbance. The full small amplitude disturbance equations are solved numerically at finite Reynolds numbers, and the inviscid limit of these equations is then investigated in some detail. It is found that instability can occur, although the stability characteristics of the flow are quite different from unbounded flows. The effects of viscosity are also calculated, asymptotically, and shown to have a stabilizing role in all the cases investigated. Exceptional regimes to the problem occur when the wavespeed of the disturbances approaches the velocity of either of the walls, and these regimes are also analyzed in some detail. Finally, the effect of imposing radiation-type boundary conditions on the upper (moving) wall (in place of impermeability) is investigated, and shown to yield results common to both bounded and unbounded flows.

Microsurgical resection of intramedullary spinal cord ependymoma.

PubMed

McCormick, Paul C

2014-09-01

Ependymomas are the most commonly occurring intramedullary spinal cord tumor in adults. With few exceptions these tumors are histologically benign, although they exhibit some biologic variability with respect to growth rate. While unencapsulated, spinal ependymomas are non-infiltrative and present a clear margin of demarcation from the surrounding spinal cord that serves as an effective dissection plane. This video demonstrates the technique of microsurgical resection of an intramedullary ependymoma through a posterior midline myelotomy. The video can be found here: http://youtu.be/lcHhymSvSqU.

Real-Time Adaptive Control of Mixing in a Plane Shear Layer

DTIC Science & Technology

1994-02-02

l’icoulement d’un fuide visqueux incompressible autour d’un cylinder fixe ou en rotation. Effet Magnus . J. Mdc. 14, 109-134. TANEDA, S. 1977 Visual study...Mokhtarian & Yokomizo 1990), and in lift enhancement schemes employing the Magnus effect (Swanson 1961). Rotation of all or part of a body may also have...coordinate system. In this work, the body-fitted grid is simply one of cylindrical polar coordinates and is time-independent, except for a = 3.25 where

Expanding the limits of endoscopic intraorbital tumor resection using 3-dimensional reconstruction.

PubMed

Gregorio, Luciano Lobato; Busaba, Nicolas Y; Miyake, Marcel M; Freitag, Suzanne K; Bleier, Benjamin S

2017-12-26

Endoscopic orbital surgery is a nascent field and new tools are required to assist with surgical planning and to ascertain the limits of the tumor resectability. We purpose to utilize three-dimensional radiographic reconstruction to define the theoretical lateral limit of endoscopic resectability of primary orbital tumors and to apply these boundary conditions to surgical cases. A three-dimensional orbital model was rendered in 4 representative patients presenting with primary orbital tumors using OsiriX open source imaging software. A 2-Dimensional plane was propagated between the contralateral nare and a line tangential to the long axis of the optic nerve reflecting the trajectory of a trans-septal approach. Any tumor volume falling medial to the optic nerve and/or within the space inferior to this plane of resectability was considered theoretically resectable regardless of how far it extended lateral to the optic nerve as nerve retraction would be unnecessary. Actual tumor volumes were then superimposed over this plan and correlated with surgical outcomes. Among the 4 lesions analyzed, two were fully medial to the optic nerve, one extended lateral to the optic nerve but remained inferior to the plane of resectability, and one extended both lateral to the optic nerve and superior to the plane of resectability. As predicted by the three-dimensional modeling, a complete resection was achieved in all lesions except one that transgressed the plane of resectability. No new diplopia or vision loss was observed in any patient. Three-dimensional reconstruction enhances preoperative planning for endoscopic orbital surgery. Tumors that extend lateral to the optic nerve may still be candidates for a purely endoscopic resection as long as they do not extend above the plane of resectability described herein. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Comparison of the Radiative Two-Flux and Diffusion Approximations

NASA Technical Reports Server (NTRS)

Spuckler, Charles M.

2006-01-01

Approximate solutions are sometimes used to determine the heat transfer and temperatures in a semitransparent material in which conduction and thermal radiation are acting. A comparison of the Milne-Eddington two-flux approximation and the diffusion approximation for combined conduction and radiation heat transfer in a ceramic material was preformed to determine the accuracy of the diffusion solution. A plane gray semitransparent layer without a substrate and a non-gray semitransparent plane layer on an opaque substrate were considered. For the plane gray layer the material is semitransparent for all wavelengths and the scattering and absorption coefficients do not vary with wavelength. For the non-gray plane layer the material is semitransparent with constant absorption and scattering coefficients up to a specified wavelength. At higher wavelengths the non-gray plane layer is assumed to be opaque. The layers are heated on one side and cooled on the other by diffuse radiation and convection. The scattering and absorption coefficients were varied. The error in the diffusion approximation compared to the Milne-Eddington two flux approximation was obtained as a function of scattering coefficient and absorption coefficient. The percent difference in interface temperatures and heat flux through the layer obtained using the Milne-Eddington two-flux and diffusion approximations are presented as a function of scattering coefficient and absorption coefficient. The largest errors occur for high scattering and low absorption except for the back surface temperature of the plane gray layer where the error is also larger at low scattering and low absorption. It is shown that the accuracy of the diffusion approximation can be improved for some scattering and absorption conditions if a reflectance obtained from a Kubelka-Munk type two flux theory is used instead of a reflection obtained from the Fresnel equation. The Kubelka-Munk reflectance accounts for surface reflection and radiation scattered back by internal scattering sites while the Fresnel reflection only accounts for surface reflections.

Automated brain tissue and myelin volumetry based on quantitative MR imaging with various in-plane resolutions.

PubMed

Andica, C; Hagiwara, A; Hori, M; Nakazawa, M; Goto, M; Koshino, S; Kamagata, K; Kumamaru, K K; Aoki, S

2018-05-01

Segmented brain tissue and myelin volumes can now be automatically calculated using dedicated software (SyMRI), which is based on quantification of R 1 and R 2 relaxation rates and proton density. The aim of this study was to determine the validity of SyMRI brain tissue and myelin volumetry using various in-plane resolutions. We scanned 10 healthy subjects on a 1.5T MR scanner with in-plane resolutions of 0.8, 2.0 and 3.0mm. Two scans were performed for each resolution. The acquisition time was 7-min and 24-sec for 0.8mm, 3-min and 9-sec for 2.0mm and 1-min and 56-sec for 3.0mm resolutions. The volumes of white matter (WM), gray matter (GM), cerebrospinal fluid (CSF), non-WM/GM/CSF (NoN), brain parenchymal volume (BPV), intracranial volume (ICV) and myelin were compared between in-plane resolutions. Repeatability for each resolution was then analyzed. No significant differences in volumes measured were found between the different in-plane resolutions, except for NoN between 0.8mm and 2.0mm and between 2.0mm and 3.0mm. The repeatability error value for the WM, GM, CSF, NoN, BPV and myelin volumes relative to ICV was 0.97%, 1.01%, 0.65%, 0.86%, 1.06% and 0.25% in 0.8mm; 1.22%, 1.36%, 0.73%, 0.37%, 1.18% and 0.35% in 2.0mm and 1.18%, 1.02%, 0.96%, 0.45%, 1.36%, and 0.28% in 3.0mm resolutions. SyMRI brain tissue and myelin volumetry with low in-plane resolution and short acquisition times is robust and has a good repeatability so could be useful for follow-up studies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

FAST (Four chamber view And Swing Technique) Echo: a Novel and Simple Algorithm to Visualize Standard Fetal Echocardiographic Planes

PubMed Central

Yeo, Lami; Romero, Roberto; Jodicke, Cristiano; Oggè, Giovanna; Lee, Wesley; Kusanovic, Juan Pedro; Vaisbuch, Edi; Hassan, Sonia S.

2010-01-01

Objective To describe a novel and simple algorithm (FAST Echo: Four chamber view And Swing Technique) to visualize standard diagnostic planes of fetal echocardiography from dataset volumes obtained with spatiotemporal image correlation (STIC) and applying a new display technology (OmniView). Methods We developed an algorithm to image standard fetal echocardiographic planes by drawing four dissecting lines through the longitudinal view of the ductal arch contained in a STIC volume dataset. Three of the lines are locked to provide simultaneous visualization of targeted planes, and the fourth line (unlocked) “swings” through the ductal arch image (“swing technique”), providing an infinite number of cardiac planes in sequence. Each line generated the following plane(s): 1) Line 1: three-vessels and trachea view; 2) Line 2: five-chamber view and long axis view of the aorta (obtained by rotation of the five-chamber view on the y-axis); 3) Line 3: four-chamber view; and 4) “Swing” line: three-vessels and trachea view, five-chamber view and/or long axis view of the aorta, four-chamber view, and stomach. The algorithm was then tested in 50 normal hearts (15.3 – 40 weeks of gestation) and visualization rates for cardiac diagnostic planes were calculated. To determine if the algorithm could identify planes that departed from the normal images, we tested the algorithm in 5 cases with proven congenital heart defects. Results In normal cases, the FAST Echo algorithm (3 locked lines and rotation of the five-chamber view on the y-axis) was able to generate the intended planes (longitudinal view of the ductal arch, pulmonary artery, three-vessels and trachea view, five-chamber view, long axis view of the aorta, four-chamber view): 1) individually in 100% of cases [except for the three-vessel and trachea view, which was seen in 98% (49/50)]; and 2) simultaneously in 98% (49/50). The “swing technique” was able to generate the three-vessels and trachea view, five-chamber view and/or long axis view of the aorta, four-chamber view, and stomach in 100% of normal cases. In the abnormal cases, the FAST Echo algorithm demonstrated the cardiac defects and displayed views that deviated from what was expected from the examination of normal hearts. The “swing technique” was useful in demonstrating the specific diagnosis due to visualization of an infinite number of cardiac planes in sequence. Conclusions This novel and simple algorithm can be used to visualize standard fetal echocardiographic planes in normal fetal hearts. The FAST Echo algorithm may simplify examination of the fetal heart and could reduce operator dependency. Using this algorithm, the inability to obtain expected views or the appearance of abnormal views in the generated planes should raise the index of suspicion for congenital heart disease. PMID:20878671

Four-chamber view and 'swing technique' (FAST) echo: a novel and simple algorithm to visualize standard fetal echocardiographic planes.

PubMed

Yeo, L; Romero, R; Jodicke, C; Oggè, G; Lee, W; Kusanovic, J P; Vaisbuch, E; Hassan, S

2011-04-01

To describe a novel and simple algorithm (four-chamber view and 'swing technique' (FAST) echo) for visualization of standard diagnostic planes of fetal echocardiography from dataset volumes obtained with spatiotemporal image correlation (STIC) and applying a new display technology (OmniView). We developed an algorithm to image standard fetal echocardiographic planes by drawing four dissecting lines through the longitudinal view of the ductal arch contained in a STIC volume dataset. Three of the lines are locked to provide simultaneous visualization of targeted planes, and the fourth line (unlocked) 'swings' through the ductal arch image (swing technique), providing an infinite number of cardiac planes in sequence. Each line generates the following plane(s): (a) Line 1: three-vessels and trachea view; (b) Line 2: five-chamber view and long-axis view of the aorta (obtained by rotation of the five-chamber view on the y-axis); (c) Line 3: four-chamber view; and (d) 'swing line': three-vessels and trachea view, five-chamber view and/or long-axis view of the aorta, four-chamber view and stomach. The algorithm was then tested in 50 normal hearts in fetuses at 15.3-40 weeks' gestation and visualization rates for cardiac diagnostic planes were calculated. To determine whether the algorithm could identify planes that departed from the normal images, we tested the algorithm in five cases with proven congenital heart defects. In normal cases, the FAST echo algorithm (three locked lines and rotation of the five-chamber view on the y-axis) was able to generate the intended planes (longitudinal view of the ductal arch, pulmonary artery, three-vessels and trachea view, five-chamber view, long-axis view of the aorta, four-chamber view) individually in 100% of cases (except for the three-vessels and trachea view, which was seen in 98% (49/50)) and simultaneously in 98% (49/50). The swing technique was able to generate the three-vessels and trachea view, five-chamber view and/or long-axis view of the aorta, four-chamber view and stomach in 100% of normal cases. In the abnormal cases, the FAST echo algorithm demonstrated the cardiac defects and displayed views that deviated from what was expected from the examination of normal hearts. The swing technique was useful for demonstrating the specific diagnosis due to visualization of an infinite number of cardiac planes in sequence. This novel and simple algorithm can be used to visualize standard fetal echocardiographic planes in normal fetal hearts. The FAST echo algorithm may simplify examination of the fetal heart and could reduce operator dependency. Using this algorithm, inability to obtain expected views or the appearance of abnormal views in the generated planes should raise the index of suspicion for congenital heart disease. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.

Outstanding catalytic activity of ultra-pure platinum nanoparticles.

PubMed

Januszewska, Aneta; Dercz, Grzegorz; Piwowar, Justyna; Jurczakowski, Rafal; Lewera, Adam

2013-12-09

Small (4 nm) nanoparticles with a narrow size distribution, exceptional surface purity, and increased surface order, which exhibits itself as an increased presence of basal crystallographic planes, can be obtained without the use of any surfactant. These nanoparticles can be used in many applications in an as-received state and are threefold more active towards a model catalytic reaction (oxidation of ethylene glycol). Furthermore, the superior properties of this material are interesting not only due to the increase in their intrinsic catalytic activity, but also due to the exceptional surface purity itself. The nanoparticles can be used directly (i.e., as-received, without any cleaning steps) in biomedical applications (i.e., as more efficient drug carriers due to an increased number of adsorption sites) and in energy-harvesting/data-storage devices. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of time restriction, 20 minutes and 94.6 months, of visual information on angular displacement during the sit-to-stand (STS) task in three planes.

PubMed

Aylar, Mozhgan Faraji; Firouzi, Faramarz; Araghi, Mandana Rahnama

2016-12-01

[Purpose] The purpose of this investigation was to assess whether or not restriction of visual information influences the kinematics of sit-to-stand (STS) performance in children. [Subjects and Methods] Five girls with congenital blindness (CB) and ten healthy girls with no visual impairments were randomly selected. The girls with congenital blindness were placed in one group and the ten girls with no visual impairments were divided into two groups of five, control and treatment groups. The participants in the treatment group were asked to close their eyes (EC) for 20 minutes before the STS test, whereas those in the control group kept their eyes open (EO). The performance of the participants in all three groups was measured using a motion capture system and two force plates. [Results] The results show that the constraint duration of visual sensory information affected the range of motion (ROM), the excursion of the dominant side ankle, and the ROM of the dominant side knee in the EC group. However, only ankle excursion on the non-dominant side was affected in the CB group, and this was only observed in the sagittal plane. [Conclusion] These results indicate that visual memory does not affect the joint angles in the frontal and transverse planes. Moreover, all of the participants could perform the STS transition without falling, indicating; the participants performed the STS maneuver correctly in all planes except the sagittal one.

Bumps of the wave structure function in non-Kolmogorov turbulence

NASA Astrophysics Data System (ADS)

Qiao, Chunhong; Lu, Lu; Zhang, Pengfei; Wang, Haitao; Huang, Honghua; Fan, Chengyu

2015-10-01

The analytical expressions for wave structure function of plane and spherical waves are derived both in the viscous dissipation and inertial range. Due to previously research, there is a discrepancy between theoretical results and the experimental datum in viscous dissipation range. In this paper, only considering the inertial range, taking plane waves for example, we give a comparison of results of WSF calculated by the analytical formula obtained in this paper and the numerical calculations of the definition at the fixed parameter (i.e., the generalized exponent α), it can be seen that the two results are in agreement with each other exactly. Based on non-Kolmogorov power spectrum, new characteristics for wave structure function (WSF) have been found for plane and spherical wave models when the different ratio of inner scale l0 and outer scale of turbulence L0 is obtained. In outer scale assumed finite case (i.e., L0 =1m), WSF obtains the maximum when α approximates to 3.3 both for plane and spherical wave models. In outer scale assumed infinite case (i.e., L0 = ∞), the WSF can be sorted into three parts, including two rapid-rising regions (i.e., 3.0 < α < 3.3 and 3.8 < α < 4.0 ) and one gently rising region (i.e., 3.3 < α < 3.8 ).Further, the changes of scaled WSF versus the ratio of separation distance and inner scale ( p/ l0 ) are investigated under mentioned above conditions for two models. In L0 = 1m case, both for plane and spherical waves, the value of α determines the bump position of WSF. In L0 = ∞ case, the bump of scaled WSF disappears when the generalized exponent has large values. The changings of scaled WSF monotonically increase as α increased when the generalized exponent is larger than11/3 for two models. Besides, the properties of spherical waves are similar to plane waves, except which the values of WSF and the scaled WSF are smaller than plane ones.

Immune responses of Holstein and Jersey calves during the preweaning and immediate postweaned periods when fed varying planes of milk replacer.

PubMed

Ballou, M A

2012-12-01

The objective was to determine the influence of breed and planes of preweaned milk replacer (MR) nutrition on the immune responses of pre- and postweaned dairy calves. Forty-two bull calves (n=20 Holstein and n=22 Jersey, 2±1 d old) were studied. Holstein and Jersey calves came from separate dairies. Calves were fed either a higher plane of MR nutrition or a lower plane of MR nutrition. Holstein and Jersey calves on the lower planes of MR nutrition were fed 454 g (as fed)/d of a 20% crude protein (CP)/20% fat MR. Holstein calves on the higher plane of MR nutrition were fed 810 and 1,180 g (as fed)/d of a 28% CP/20% fat MR for wk 1 and wk 2 to 6, respectively. Jersey calves on the higher plane of nutrition were fed 568 and 680 g (as fed)/d of a 28% CP/25% fat MR for wk 1 and wk 2 to 6, respectively. On d 4, 42, and 77, peripheral blood was collected for ex vivo immunological analyses, and on d 7 all calves were challenged subcutaneously with commercially available lipopolysaccharide (LPS) from Escherichia coli (4 µg/kg of body weight); clinical and biochemical responses were evaluated at 0, 1, 2, 3, 4, 5, 6, 9, 12, 24, and 72 h. We observed a breed difference in total serum protein, wherein Jersey calves had higher concentrations than Holsteins. Holsteins and calves fed the higher plane of MR nutrition had greater glucose concentrations following the LPS challenge. With the exception of plasma haptoglobin concentrations at 24 h postchallenge, we observed no treatment × time interactions following the LPS challenge. Calves fed higher planes of MR nutrition had greater plasma haptoglobin concentrations 24h following the LPS challenge. Isolated mononuclear cells from Holstein calves secreted more tumor necrosis factor-α than did cells from Jersey calves when stimulated ex vivo with LPS on d 77. In addition, when whole blood was incubated with a live enteropathogenic E. coli culture, blood from Holsteins had a greater killing capacity than did whole blood from Jerseys. Calves fed higher planes of MR nutrition had greater neutrophil oxidative burst intensities at d 77 when cocultured with E. coli for 10 min. In addition, Jersey calves fed the lower plane of MR nutrition had reduced neutrophil oxidative burst capacity and whole blood E. coli killing at d 77 compared with the other groups. These data indicate that Jersey calves had lower measures of many innate immune variables despite likely having greater passive transfer, as evidenced by greater total serum protein concentrations. Furthermore, feeding a higher plane of MR nutrition to Jersey calves improved some postweaning innate immune responses. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Opening of an interface flaw in a layered elastic half-plane under compressive loading

NASA Technical Reports Server (NTRS)

Kennedy, J. M.; Fichter, W. B.; Goree, J. G.

1984-01-01

A static analysis is given of the problem of an elastic layer perfectly bonded, except for a frictionless interface crack, to a dissimilar elastic half-plane. The free surface of the layer is loaded by a finite pressure distribution directly over the crack. The problem is formulated using the two dimensional linear elasticity equations. Using Fourier transforms, the governing equations are converted to a pair of coupled singular integral equations. The integral equations are reduced to a set of simultaneous algebraic equations by expanding the unknown functions in a series of Jacobi polynomials and then evaluating the singular Cauchy-type integrals. The resulting equations are found to be ill-conditioned and, consequently, are solved in the least-squares sense. Results from the analysis show that, under a normal pressure distribution on the free surface of the layer and depending on the combination of geometric and material parameters, the ends of the crack can open. The resulting stresses at the crack-tips are singular, implying that crack growth is possible. The extent of the opening and the crack-top stress intensity factors depend on the width of the pressure distribution zone, the layer thickness, and the relative material properties of the layer and half-plane.

Infrared spectroscopy of matrix-isolated polycyclic aromatic hydrocarbon cations. 2. The members of the thermodynamically most favorable series through coronene

NASA Technical Reports Server (NTRS)

Hudgins, D. M.; Allamandola, L. J.

1995-01-01

Gaseous, ionized polycyclic aromatic hydrocarbons (PAHs) are thought to be responsible for a very common family of interstellar infrared emission bands. Here the near- and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene:phenanthrene, pyrene, benzo[e]pyrene, benzo[ghi]perylene, and coronene, are presented to test this hypothesis. For those molecules that have been studied previously (pyrene, pyrene-d10, and coronene), band positions and relative intensities are in agreement. In all of these cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeuteriophenanthrene, pyrene, benzo[ghi]perylene, and coronene cations. With the exception of coronene, the cation bands corresponding to the CC modes are typically 2-5 times more intense than those of the CH out-of-plane bending vibrations. For the cations, the CC stretching and CH in-plane bending modes give rise to bands that are an order of magnitude stronger than those of the neutral species, and the CH out-of-plane bends produce bands that are 5-20 times weaker than those of the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.

Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations

NASA Technical Reports Server (NTRS)

Hudgins, D. M.; Allamandola, L. J.

1995-01-01

Gaseous, ionized polycyclic aromatic hydrocarbons (PAHs) are thought to be responsible for a very common family of interstellar infrared emission bands. Here the near- and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene: phenanthrene, pyrene, benzo(e)pyrene, benzo-(ghi)perylene, and coronene, are presented to test this hypothesis. For those molecules that have been studied previously (pyrene, pyrene-d(sub 10), and coronene), band positions and relative intensities are in agreement. In all of these cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeuteriophenanthrene, pyrene, benzo(ghi]perylene, and coronene cations. With the exception of coronene, the cation bands corresponding to the CC modes are typically 2-5 times more intense than those of the CH out-of-plane bending vibrations. For the cations, the CC stretching and CH in-plane bending modes give rise to bands that are an order of magnitude stronger than those of the neutral species, and the CH out-of-plane bends produce bands that are 5-20 times weaker than those of the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.

Stiffness optimization of non-linear elastic structures

DOE PAGES

Wallin, Mathias; Ivarsson, Niklas; Tortorelli, Daniel

2017-11-13

Our paper revisits stiffness optimization of non-linear elastic structures. Due to the non-linearity, several possible stiffness measures can be identified and in this work conventional compliance, i.e. secant stiffness designs are compared to tangent stiffness designs. The optimization problem is solved by the method of moving asymptotes and the sensitivities are calculated using the adjoint method. And for the tangent cost function it is shown that although the objective involves the third derivative of the strain energy an efficient formulation for calculating the sensitivity can be obtained. Loss of convergence due to large deformations in void regions is addressed bymore » using a fictitious strain energy such that small strain linear elasticity is approached in the void regions. We formulate a well-posed topology optimization problem by using restriction which is achieved via a Helmholtz type filter. The numerical examples provided show that for low load levels, the designs obtained from the different stiffness measures coincide whereas for large deformations significant differences are observed.« less

Strength and deformation behaviors of veined marble specimens after vacuum heat treatment under conventional triaxial compression

NASA Astrophysics Data System (ADS)

Su, Haijian; Jing, Hongwen; Yin, Qian; Yu, Liyuan; Wang, Yingchao; Wu, Xingjie

2017-10-01

The mechanical behaviors of rocks affected by high temperature and stress are generally believed to be significant for the stability of certain projects involving rocks, such as nuclear waste storage and geothermal resource exploitation. In this paper, veined marble specimens were treated to high temperature treatment and then used in conventional triaxial compression tests to investigate the effect of temperature, confining pressure, and vein angle on strength and deformation behaviors. The results show that the strength and deformation parameters of the veined marble specimens changed with the temperature, presenting a critical temperature of 600 °C. The triaxial compression strength of a horizontal vein (β = 90°) is obviously larger than that of a vertical vein (β = 0°). The triaxial compression strength, elasticity modulus, and secant modulus have an approximately linear relation to the confining pressure. Finally, Mohr-Coulomb and Hoek-Brown criteria were respectively used to analyze the effect of confining pressure on triaxial compression strength.

Experimental and numerical study of the effect of rolling parameters on shaft deformation during the longitudinal rolling process

NASA Astrophysics Data System (ADS)

Kowalik, Marek; Trzepiecinski, Tomasz

2018-05-01

This paper presents the characteristics of the process of longitudinal rolling of shafts and the geometry of the working section of forming rollers with a secant profile. In addition, the analytical formulae defining the geometry of a roller profile were determined. The experiments were carried out on shafts made of S235JR and C45 structural steels and the MSC.Marc + Mentat program was used for the numerical analysis of the rolling process based on the finite element method. The paper analyses the effect of roller geometry on the changes in value of the widening coefficient and the diameter reduction coefficient for the first forming passage. It was found that the mechanical properties of the shaft material have a slight influence on the widening coefficient. The value of the widening coefficient of the shaft increases with increase in the initial diameter of the shaft. Increasing shaft diameter causes an increase of strain gradient on the cross-section of the shaft.

Stiffness optimization of non-linear elastic structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallin, Mathias; Ivarsson, Niklas; Tortorelli, Daniel

Our paper revisits stiffness optimization of non-linear elastic structures. Due to the non-linearity, several possible stiffness measures can be identified and in this work conventional compliance, i.e. secant stiffness designs are compared to tangent stiffness designs. The optimization problem is solved by the method of moving asymptotes and the sensitivities are calculated using the adjoint method. And for the tangent cost function it is shown that although the objective involves the third derivative of the strain energy an efficient formulation for calculating the sensitivity can be obtained. Loss of convergence due to large deformations in void regions is addressed bymore » using a fictitious strain energy such that small strain linear elasticity is approached in the void regions. We formulate a well-posed topology optimization problem by using restriction which is achieved via a Helmholtz type filter. The numerical examples provided show that for low load levels, the designs obtained from the different stiffness measures coincide whereas for large deformations significant differences are observed.« less

Modelling Dowel Action of Discrete Reinforcing Bars in Cracked Concrete Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwan, A. K. H.; Ng, P. L.; Lam, J. Y. K.

2010-05-21

Dowel action is one of the component actions for shear force transfer in cracked reinforced concrete. In finite element analysis of concrete structures, the use of discrete representation of reinforcing bars is considered advantageous over the smeared representation due to the relative ease of modelling the bond-slip behaviour. However, there is very limited research on how to simulate the dowel action of discrete reinforcing bars. Herein, a numerical model for dowel action of discrete reinforcing bars crossing cracks in concrete is developed. The model features the derivation of dowel stiffness matrix based on beam-on-elastic-foundation theory and the direct assemblage ofmore » dowel stiffness into the concrete element stiffness matrices. The dowel action model is incorporated in a nonlinear finite element programme with secant stiffness formulation. Deep beams tested in the literature are analysed and it is found that the incorporation of dowel action model improves the accuracy of analysis.« less

Geometric descriptions of entangled states by auxiliary varieties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holweck, Frederic; Luque, Jean-Gabriel; Thibon, Jean-Yves

2012-10-15

The aim of the paper is to propose geometric descriptions of multipartite entangled states using algebraic geometry. In the context of this paper, geometric means each stratum of the Hilbert space, corresponding to an entangled state, is an open subset of an algebraic variety built by classical geometric constructions (tangent lines, secant lines) from the set of separable states. In this setting, we describe well-known classifications of multipartite entanglement such as 2 Multiplication-Sign 2 Multiplication-Sign (n+ 1), for n Greater-Than-Or-Slanted-Equal-To 1, quantum systems and a new description with the 2 Multiplication-Sign 3 Multiplication-Sign 3 quantum system. Our results complete themore » approach of Miyake and make stronger connections with recent work of algebraic geometers. Moreover, for the quantum systems detailed in this paper, we propose an algorithm, based on the classical theory of invariants, to decide to which subvariety of the Hilbert space a given state belongs.« less

Exploring Mars: The Ares Payload Service (APS)

NASA Astrophysics Data System (ADS)

Bowen, Justin; Lusignan, Bruce

1999-08-01

In last year's Mars Society convention we introduced the results of five years of studies of space launch capability for the second millennium. We concluded that Single Stage to Orbit (SSTO) vehicles such as the Delta Clipper X33, and X34 cannot make it to orbit from the Earth's surface. Whether taking off vertically or horizontally or landing vertically or horizontally, the rocket equations, the performance of available fuels, and the realities of the weight and strength of materials leave no margin for payload. The promised savings from SSTO systems are illusory. However, a configuration that is able to deliver useful payload to orbit is the Single step to Orbit, SsTO, a rocket plane that is released fully fueled, from 35,000 to 40,000 feet altitude. Three approaches have been proposed. The Hot'l and Molnya Corporation designs carry the fueled rocket plane to altitude on the back of a carrier aircraft. In this design the carrier aircraft is Russia's Antonov 225 the world's largest cargo plane. The rocket plane is a modified version of the Buran, Russia's own space shuttle. Another configuration is Kelly Aviation's concept in which the fully fueled rocket plane is towed to altitude by the cargo plane and then released. A third approach is based on the early "X" planes, which were dropped from the belly of the carrier plane. While the rocket equations indicate that these three concepts can deliver useful payloads, the Stanford review found significant advantages to the approach of Pioneer Rocket, in which the rocket plane flies up to the carrier plane with conventional jet engines, docks, and then loads on the oxidizer for the flight to orbit. This architecture has more reasonable abort modes in case of system failure in either aircraft and can deliver a larger final payload to orbit for a given sized carrier. The Stanford recommendation is that the carrier aircraft be the Antonov 225. A design based on this was presented in a report last year. Refinements to the design notably an improved re-entry cooling system and fueling stability analysis were done this year. More technical detail and a proposed international consortium to develop the SSTO is presented in another session of this year's Mars convention. We believe that there will be no human exploration of Mars based on the Shuttle or Expendable launch vehicles, and no resources available except for a cooperative international program. However, just as the world is learning to cooperate in peacekeeping, we hold out the hope that similar cooperation will develop for Mars exploration. With that in mind, this year we asked the question- "How will the human mission get to Mars if it has to use the SsTO for transportation?"

Exploring Mars: the Ares Payload Service (APS)

NASA Technical Reports Server (NTRS)

Bowen, Justin; Lusignan, Bruce

1999-01-01

In last year's Mars Society convention we introduced the results of five years of studies of space launch capability for the second millennium. We concluded that Single Stage to Orbit (SSTO) vehicles such as the Delta Clipper X33, and X34 cannot make it to orbit from the Earth's surface. Whether taking off vertically or horizontally or landing vertically or horizontally, the rocket equations, the performance of available fuels, and the realities of the weight and strength of materials leave no margin for payload. The promised savings from SSTO systems are illusory. However, a configuration that is able to deliver useful payload to orbit is the Single step to Orbit, SsTO, a rocket plane that is released fully fueled, from 35,000 to 40,000 feet altitude. Three approaches have been proposed. The Hot'l and Molnya Corporation designs carry the fueled rocket plane to altitude on the back of a carrier aircraft. In this design the carrier aircraft is Russia's Antonov 225 the world's largest cargo plane. The rocket plane is a modified version of the Buran, Russia's own space shuttle. Another configuration is Kelly Aviation's concept in which the fully fueled rocket plane is towed to altitude by the cargo plane and then released. A third approach is based on the early "X" planes, which were dropped from the belly of the carrier plane. While the rocket equations indicate that these three concepts can deliver useful payloads, the Stanford review found significant advantages to the approach of Pioneer Rocket, in which the rocket plane flies up to the carrier plane with conventional jet engines, docks, and then loads on the oxidizer for the flight to orbit. This architecture has more reasonable abort modes in case of system failure in either aircraft and can deliver a larger final payload to orbit for a given sized carrier. The Stanford recommendation is that the carrier aircraft be the Antonov 225. A design based on this was presented in a report last year. Refinements to the design notably an improved re-entry cooling system and fueling stability analysis were done this year. More technical detail and a proposed international consortium to develop the SSTO is presented in another session of this year's Mars convention. We believe that there will be no human exploration of Mars based on the Shuttle or Expendable launch vehicles, and no resources available except for a cooperative international program. However, just as the world is learning to cooperate in peacekeeping, we hold out the hope that similar cooperation will develop for Mars exploration. With that in mind, this year we asked the question- "How will the human mission get to Mars if it has to use the SsTO for transportation?"

Asymmetric rapid maxillary expansion in true unilateral crossbite malocclusion: a prospective controlled clinical study.

PubMed

Ileri, Zehra; Basciftci, Faruk Ayhan

2015-03-01

To investigate the short-term effects of the asymmetric rapid maxillary (ARME) appliance on the vertical, sagittal, and transverse planes in patients with true unilateral posterior crossbite. Subjects were divided into two groups. The treatment group was comprised of 21 patients with unilateral posterior crossbite (mean age  =  13.3 ± 2.1 years). Members of this group were treated with the ARME appliance. The control group was comprised of 17 patients with Angle Class I who were kept under observation (mean age  =  12.3 ± 0.8 years). Lateral and frontal cephalograms were taken before the expansion (T1), immediately after expansion (T2), and at postexpansion retention (T3) in the treatment group and at preobservation (T1) and postobservation (T2) in the control group. A total of 34 measurements were assessed on cephalograms. For statistical analysis, the Wilcoxon test and analysis of covariance were used. The ARME appliance produced significant increases in nasal, maxillary base, upper arch, and lower arch dimensions (P < .01) and a clockwise rotation of the occlusal plane (P  =  .001). The ARME appliance created asymmetric increments in the transversal dimensions of the nose, maxilla, and upper arch in the short term. Asymmetric expansion therapy for subjects with unilateral maxillary deficiency may provide satisfactory outcomes in adolescents, with the exception of mandibular arch expansion. The triangular pattern of expansion caused clockwise rotation of the mandible and the occlusal plane and produced significant alterations in the vertical facial dimensions, whereas it created no displacement in maxilla in the sagittal plane.

Integrated performance of a frequency domain multiplexing readout in the SPT-3G receiver

NASA Astrophysics Data System (ADS)

Bender, A. N.; Ade, P. A. R.; Anderson, A. J.; Avva, J.; Ahmed, Z.; Arnold, K.; Austermann, J. E.; Basu Thakur, R.; Benson, B. A.; Bleem, L. E.; Byrum, K.; Carlstrom, J. E.; Carter, F. W.; Chang, C. L.; Cho, H. M.; Cliche, J. F.; Crawford, T. M.; Cukierman, A.; Czaplewski, D. A.; Ding, J.; Divan, R.; de Haan, T.; Dobbs, M. A.; Dutcher, D.; Everett, W.; Gilbert, A.; Groh, J. C.; Guyser, R.; Halverson, N. W.; Harke-Hosemann, A.; Harrington, N. L.; Hattori, K.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Huang, N.; Irwin, K. D.; Jeong, O.; Khaire, T.; Korman, M.; Kubik, D.; Kuo, C. L.; Lee, A. T.; Leitch, E. M.; Lendinez, S.; Meyer, S. S.; Miller, C. S.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nguyen, H.; Novosad, V.; Padin, S.; Pan, Z.; Pearson, J.; Posada, C. M.; Rahlin, A.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Shariff, J. A.; Shirley, Ian; Shirokoff, E.; Smecher, G.; Sobrin, J.; Stan, L.; Stark, A. A.; Story, K.; Suzuki, A.; Tang, Q. Y.; Thompson, K. L.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Yoon, K. W.

2016-07-01

The third generation receiver for the South Pole Telescope, SPT-3G, will make extremely deep, arcminuteresolution maps of the temperature and polarization of the cosmic microwave background. The SPT-3G maps will enable studies of the B-mode polarization signature, constraining primordial gravitational waves as well as the effect of massive neutrinos on structure formation in the late universe. The SPT-3G receiver will achieve exceptional sensitivity through a focal plane of 16,000 transition-edge sensor bolometers, an order of magnitude more than the current SPTpol receiver. SPT-3G uses a frequency domain multiplexing (fMux) scheme to read out the focal plane, combining the signals from 64 bolometers onto a single pair of wires. The fMux readout facilitates the large number of detectors in the SPT-3G focal plane by limiting the thermal load due to readout wiring on the 250 millikelvin cryogenic stage. A second advantage of the fMux system is that the operation of each bolometer can be optimized. In addition to these benefits, the fMux readout introduces new challenges into the design and operation of the receiver. The bolometers are operated at a range of frequencies up to 5 MHz, requiring control of stray reactances over a large bandwidth. Additionally, crosstalk between multiplexed detectors will inject large false signals into the data if not adequately mitigated. SPT-3G is scheduled to deploy to the South Pole Telescope in late 2016. Here, we present the pre-deployment performance of the fMux readout system with the SPT-3G focal plane.

Non-linear second harmonic generation (SHG) studies of BaTiO3/SrTiO3 superlattices

NASA Astrophysics Data System (ADS)

Vlahos, Eftihia; Lee, Che-Hui; Wu, Pingping; Wung Bark, Chung; Jang, Ho Won; Folkman, Chad; Hyub Baek, Seung; Park, J. W.; Biegalski, Mike; Tenne, Dmitri; Schlom, Darrell; Chen, Long-Qing; Eom, Chang-Beom; Gopalan, Venkatraman

2010-03-01

Theoretical phase-field simulations predict that certain types of superlattices consisting of alternating (BaTiO3)n/(SrTiO3)n layers have novel vortex domain wall configurations which give rise to exceptionally high polarization tunability combined with negligible polarization hysteresis. Optical second harmonic generation (SHG) was used to probe the phase and transition temperatures of multilayer (BaTiO3)m/(SrTiO3)n superlattices, as a function of epitaxial strain. In addition, in-plane electro-optic measurements were carried out. The experimental results are in excellent agreement both with theoretical predictions, as well as the temperature-strain phase diagram obtained experimentally from UV Raman studies. The ferroelectric, in-plane SHG signal, from the tensile strained SrTiO3 layers reveals an mm2 point group symmetry, whereas the point group symmetry of the compressively strained BaTiO3 layers, was determined to be 4mm.

Weak ferromagnetic order breaking the threefold rotational symmetry of the underlying kagome lattice in CdC u3(OH) 6(NO3)2.H2O

NASA Astrophysics Data System (ADS)

Okuma, Ryutaro; Yajima, Takeshi; Nishio-Hamane, Daisuke; Okubo, Tsuyoshi; Hiroi, Zenji

2017-03-01

Novel magnetic phases are expected to occur in highly frustrated spin systems. Here, we study the structurally perfect kagome antiferromagnet CdC u3(OH) 6(NO3)2.H2O by magnetization, magnetic torque, and heat capacity measurements using single crystals. An antiferromagnetic order accompanied by a small spontaneous magnetization that surprisingly is confined in the kagome plane sets in at TN˜4 K , well below the nearest-neighbor exchange interaction J /kB=45 K . This suggests that a unique "q =0 " type 120∘ spin structure with "negative" (downward) vector chirality, which breaks the underlying threefold rotational symmetry of the kagome lattice and thus allows a spin canting within the plane, is exceptionally realized in this compound rather than a common one with "positive" (upward) vector chirality. The origin is discussed in terms of the Dzyaloshinskii-Moriya interaction.

Endoscopic ultrasound description of liver segmentation and anatomy.

PubMed

Bhatia, Vikram; Hijioka, Susumu; Hara, Kazuo; Mizuno, Nobumasa; Imaoka, Hiroshi; Yamao, Kenji

2014-05-01

Endoscopic ultrasound (EUS) can demonstrate the detailed anatomy of the liver from the transgastric and transduodenal routes. Most of the liver segments can be imaged with EUS, except the right posterior segments. The intrahepatic vascular landmarks include the major hepatic veins, portal vein radicals, hepatic arterial branches, and the inferior vena cava, and the venosum and teres ligaments are other important intrahepatic landmarks. The liver hilum and gallbladder serve as useful surface landmarks. Deciphering liver segmentation and anatomy by EUS requires orienting the scan planes with these landmarkstructures, and is different from the static cross-sectional radiological images. Orientation during EUS requires appreciation of the numerous scan planes possible in real-time, and the direction of scanning from the stomach and duodenal bulb. We describe EUS imaging of the liver with a curved linear probe in a step-by-step approach, with the relevant anatomical details, potential applications, and pitfalls of this novel EUS application. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

Thermodynamic evidence for a nematic phase transition at the onset of the pseudogap in YBa2Cu3Oy

NASA Astrophysics Data System (ADS)

Sato, Y.; Kasahara, S.; Murayama, H.; Kasahara, Y.; Moon, E.-G.; Nishizaki, T.; Loew, T.; Porras, J.; Keimer, B.; Shibauchi, T.; Matsuda, Y.

2017-11-01

A long-standing controversial issue in the quest to understand the superconductivity in cuprates is the nature of the enigmatic pseudogap region of the phase diagram. Especially important is whether the pseudogap state is a distinct thermodynamic phase characterized by broken symmetries below the onset temperature T*. Here we report torque-magnetometry measurements of anisotropic susceptibility within the ab planes in orthorhombic YBa2Cu3Oy with exceptionally high precision. The in-plane anisotropy displays a significant increase with a distinct kink at the pseudogap onset temperature T*, showing a remarkable scaling behaviour with respect to T/T* in a wide doping range. Our systematic analysis reveals that the rotational symmetry breaking sets in at T* in the limit where the effect of orthorhombicity is eliminated. These results provide thermodynamic evidence that the pseudogap onset is associated with a second-order nematic phase transition, which differs from the recently reported charge-density-wave transition that accompanies translational symmetry breaking.

Rapid granular flows on a rough incline: phase diagram, gas transition, and effects of air drag.

PubMed

Börzsönyi, Tamás; Ecke, Robert E

2006-12-01

We report experiments on the overall phase diagram of granular flows on an incline with emphasis on high inclination angles where the mean layer velocity approaches the terminal velocity of a single particle free falling in air. The granular flow was characterized by measurements of the surface velocity, the average layer height, and the mean density of the layer as functions of the hopper opening, the plane inclination angle, and the downstream distance x of the flow. At high inclination angles the flow does not reach an x -invariant steady state over the length of the inclined plane. For low volume flow rates, a transition was detected between dense and very dilute (gas) flow regimes. We show using a vacuum flow channel that air did not qualitatively change the phase diagram and did not quantitatively modify mean flow velocities of the granular layer except for small changes in the very dilute gaslike phase.

Optoelectronic Tool Adds Scale Marks to Photographic Images

NASA Technical Reports Server (NTRS)

Stevenson, Charlie; Rivera, Jorge; Youngquist, Robert; Cox, Robert; Haskell, William

2003-01-01

A simple, easy-to-use optoelectronic tool projects scale marks that become incorporated into photographic images (including film and electronic images). The sizes of objects depicted in the images can readily be measured by reference to the scale marks. The role played by the scale marks projected by this tool is the same as that of the scale marks on a ruler placed in a scene for the purpose of establishing a length scale. However, this tool offers the advantage that it can put scale marks quickly and safely in any visible location, including a location in which placement of a ruler would be difficult, unsafe, or time-consuming. The tool (see Figure 1) includes an aluminum housing, within which are mounted four laser diodes that operate at a wavelength of 670 nm. The laser diodes are spaced 1 in. (2.54 cm) apart along a baseline. The laser diodes are mounted with setscrews, which are used to adjust their beams to make them all parallel to each other and perpendicular to the baseline. During the adjustment process, the effect of the adjustments is observed by measuring the positions of the laser-beam spots on a target 80 ft (approx.24 m) away. Once the adjustments have been completed, the laser beams define three 1-in. (2.54-cm) intervals and the location of each beam is defined to within 1/16 in. (approx.1.6 mm) at any target distance out to about 80 ft (approx.24 m). The distance between the laser-beam spots as seen in an image is strictly defined only along an axis parallel to the baseline and perpendicular to the laser beam (also perpendicular to the line of sight of the camera, assuming that the camera-to-target distance is much greater than the distance between the tool and the camera lens). If a flat target surface illuminated by the laser beams is tilted with respect to the aforesaid axis, then the distance along the target surface between scale marks is proportional to the secant of the tilt angle. If one knows the tilt angle, one can correct for it. Even if one does not know the tilt angle precisely, it may not matter: For example, at a tilt of 10 , the secant is approximately 1.0154, so that the tilt error is only about 1.54 percent, which is negligibly small for a typical application in which only approximate measurements are needed.

Video raster stereography back shape reconstruction: a reliability study for sagittal, frontal, and transversal plane parameters.

PubMed

Schroeder, J; Reer, R; Braumann, K M

2015-02-01

As reliability of raster stereography was proved only for sagittal plane parameters with repeated measures on the same day, the present study was aiming at investigating variability and reliability of back shape reconstruction for all dimensions (sagittal, frontal, transversal) and for different intervals. For a sample of 20 healthy volunteers, intra-individual variability (SEM and CV%) and reliability (ICC ± 95% CI) were proved for sagittal (thoracic kyphosis, lumbar lordosis, pelvis tilt angle, and trunk inclination), frontal (pelvis torsion, pelvis and trunk imbalance, vertebral side deviation, and scoliosis angle), transversal (vertebral rotation), and functional (hyperextension) spine shape reconstruction parameters for different test-retest intervals (on the same day, between-day, between-week) by means of video raster stereography. Reliability was high for the sagittal plane (pelvis tilt, kyphosis and lordosis angle, and trunk inclination: ICC > 0.90), and good to high for lumbar mobility (0.86 < ICC < 0.97). Apart from sagittal plane spinal alignment, there was a lack of certainty for a high reproducibility indicated by wider ICC confidence intervals. So, reliability was fair to high for vertebral side deviation and the scoliosis angle (0.71 < ICC < 0.95), and poor to good for vertebral rotation values as well as for frontal plane upper body and pelvis position parameters (0.65 < ICC < 0.92). Coefficients for the between-day and between-week interval were a little lower than for repeated measures on the same day. Variability (SEM) was less than 1.5° or 1.5 mm, except for trunk inclination. Relative variability (CV) was greater in global trunk position and pelvis parameters (35-98%) than in scoliosis (14-20%) or sagittal sway parameters (4-8 %). Although we found a lower reproducibility for the frontal plane, raster stereography is considered to be a reliable method for the non-invasive, three-dimensional assessment of spinal alignment in normal non-scoliotic individuals in the sagittal plane and partly for scoliosis parameters, which fulfils scientific as well as practical recommendations for spine shape screening and monitoring, but cross-sectional or follow-up effect analyses should take into account the degree of reliability differing in various spine shape parameters. Further investigations should be conducted to analyse reliability in scoliosis patients with differing spinal deformities.

JPEG 2000 Encoding with Perceptual Distortion Control

NASA Technical Reports Server (NTRS)

Watson, Andrew B.; Liu, Zhen; Karam, Lina J.

2008-01-01

An alternative approach has been devised for encoding image data in compliance with JPEG 2000, the most recent still-image data-compression standard of the Joint Photographic Experts Group. Heretofore, JPEG 2000 encoding has been implemented by several related schemes classified as rate-based distortion-minimization encoding. In each of these schemes, the end user specifies a desired bit rate and the encoding algorithm strives to attain that rate while minimizing a mean squared error (MSE). While rate-based distortion minimization is appropriate for transmitting data over a limited-bandwidth channel, it is not the best approach for applications in which the perceptual quality of reconstructed images is a major consideration. A better approach for such applications is the present alternative one, denoted perceptual distortion control, in which the encoding algorithm strives to compress data to the lowest bit rate that yields at least a specified level of perceptual image quality. Some additional background information on JPEG 2000 is prerequisite to a meaningful summary of JPEG encoding with perceptual distortion control. The JPEG 2000 encoding process includes two subprocesses known as tier-1 and tier-2 coding. In order to minimize the MSE for the desired bit rate, a rate-distortion- optimization subprocess is introduced between the tier-1 and tier-2 subprocesses. In tier-1 coding, each coding block is independently bit-plane coded from the most-significant-bit (MSB) plane to the least-significant-bit (LSB) plane, using three coding passes (except for the MSB plane, which is coded using only one "clean up" coding pass). For M bit planes, this subprocess involves a total number of (3M - 2) coding passes. An embedded bit stream is then generated for each coding block. Information on the reduction in distortion and the increase in the bit rate associated with each coding pass is collected. This information is then used in a rate-control procedure to determine the contribution of each coding block to the output compressed bit stream.

Two charges on a plane in a magnetic field: hidden algebra, (particular) integrability, polynomial eigenfunctions

NASA Astrophysics Data System (ADS)

Turbiner, A. V.; Escobar-Ruiz, M. A.

2013-07-01

The quantum mechanics of two Coulomb charges on a plane (e1, m1) and (e2, m2) subject to a constant magnetic field B perpendicular to the plane is considered. Four integrals of motion are explicitly indicated. It is shown that for two physically important particular cases, namely that of two particles of equal Larmor frequencies, {e_c} \\propto \\frac{e_1}{m_1}-\\frac{e_2}{m_2}=0 (e.g. two electrons) and one of a neutral system (e.g. the electron-positron pair, hydrogen atom) at rest (the center-of-mass momentum is zero) some outstanding properties occur. They are the most visible in double polar coordinates in CMS (R, ϕ) and relative (ρ, φ) coordinate systems: (i) eigenfunctions are factorizable, all factors except one with the explicit ρ-dependence are found analytically, they have definite relative angular momentum, (ii) dynamics in the ρ-direction is the same for both systems, it corresponds to a funnel-type potential and it has hidden sl(2) algebra, at some discrete values of dimensionless magnetic fields b ⩽ 1, (iii) particular integral(s) occur, (iv) the hidden sl(2) algebra emerges in finite-dimensional representation, thus, the system becomes quasi-exactly-solvable and (v) a finite number of polynomial eigenfunctions in ρ appear. Nine families of eigenfunctions are presented explicitly.

Universal rule for the symmetric division of plant cells

PubMed Central

Besson, Sébastien; Dumais, Jacques

2011-01-01

The division of eukaryotic cells involves the assembly of complex cytoskeletal structures to exert the forces required for chromosome segregation and cytokinesis. In plants, empirical evidence suggests that tensional forces within the cytoskeleton cause cells to divide along the plane that minimizes the surface area of the cell plate (Errera’s rule) while creating daughter cells of equal size. However, exceptions to Errera’s rule cast doubt on whether a broadly applicable rule can be formulated for plant cell division. Here, we show that the selection of the plane of division involves a competition between alternative configurations whose geometries represent local area minima. We find that the probability of observing a particular division configuration increases inversely with its relative area according to an exponential probability distribution known as the Gibbs measure. Moreover, a comparison across land plants and their most recent algal ancestors confirms that the probability distribution is widely conserved and independent of cell shape and size. Using a maximum entropy formulation, we show that this empirical division rule is predicted by the dynamics of the tense cytoskeletal elements that lead to the positioning of the preprophase band. Based on the fact that the division plane is selected from the sole interaction of the cytoskeleton with cell shape, we posit that the new rule represents the default mechanism for plant cell division when internal or external cues are absent. PMID:21383128

Anterior deltoid deficiency in reverse total shoulder replacement: a biomechanical study with cadavers.

PubMed

Gulotta, L V; Choi, D; Marinello, P; Wright, T; Cordasco, F A; Craig, E V; Warren, R F

2012-12-01

Reverse total shoulder replacement (RTSR) depends on adequate deltoid function for a successful outcome. However, the anterior deltoid and/or axillary nerve may be damaged due to prior procedures or injury. The purpose of this study was to determine the compensatory muscle forces required for scapular plane elevation following RTSR when the anterior deltoid is deficient. The soft tissues were removed from six cadaver shoulders, except for tendon attachments. After implantation of the RTSR, the shoulders were mounted on a custom-made shoulder simulator to determine the mean force in each muscle required to achieve 30° and 60° of scapular plane elevation. Two conditions were tested: 1) Control with an absent supraspinatus and infraspinatus; and 2) Control with anterior deltoid deficiency. Anterior deltoid deficiency resulted in a mean increase of 195% in subscapularis force at 30° when compared with the control (p = 0.02). At 60°, the subscapularis force increased a mean of 82% (p < 0.001) and the middle deltoid force increased a mean of 26% (p = 0.04). Scapular plane elevation may still be possible following an RTSR in the setting of anterior deltoid deficiency. When the anterior deltoid is deficient, there is a compensatory increase in the force required by the subscapularis and middle deltoid. Attempts to preserve the subscapularis, if present, might maximise post-operative function.

Non-Equilibrium Turbulence Modeling for High Lift Aerodynamics

NASA Technical Reports Server (NTRS)

Durbin, P. A.

1998-01-01

This phase is discussed in ('Non linear kappa - epsilon - upsilon(sup 2) modeling with application to high lift', Application of the kappa - epsilon -upsilon(sup 2) model to multi-component airfoils'). Further results are presented in 'Non-linear upsilon(sup 2) - f modeling with application to high-lift' The ADI solution method in the initial implementation was very slow to converge on multi-zone chimera meshes. I modified the INS implementation to use GMRES. This provided improved convergence and less need for user intervention in the solution process. There were some difficulties with implementation into the NASA compressible codes, due to their use of approximate factorization. The Helmholtz equation for f is not an evolution equation, so it is not of the form assumed by the approximate factorization method. Although The Kalitzin implementation involved a new solution algorithm ('An implementation of the upsilon(sup 2) - f model with application to transonic flows'). The algorithm involves introducing a relaxation term in the f-equation so that it can be factored. The factorization can be into a plane and a line, with GMRES used in the plane. The NASA code already evaluated coefficients in planes, so no additional memory is required except that associated the the GMRES algorithm. So the scope of this project has expanded via these interactions. . The high-lift work has dovetailed into turbine applications.

Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations. Part 2; The Members of the Thermodynamically Most Favorable Series through Coronene

NASA Technical Reports Server (NTRS)

Hudgins, D. M.; Allamandola, L. J.

1995-01-01

Gaseous, ionized polycyclic aromatic hydrocarbons (PAHS) are thought to be responsible for a very common family of interstellar infrared emission bands. Here the near- and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene: phenanthrene, pyrene, benzo[e]pyrene, benzo-[ghi]perylene, and coronene, are presented to test this hypothesis. For those molecules that have been studied previously (pyrene, pyrene-d(sub 10), and coronene), band positions and relative intensities are in agreement. In all of these cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeuteriophenanthrene, pyrene, benzo[ghi]perylene, and coronene cations. With the exception of coronene, the cation bands corresponding to the CC modes are typically 2-5 times more intense than those of the CH out-of-plane bending vibrations. For the cations, the CC stretching and CH in-plane bending modes give rise to bands that are an order of magnitude stronger than those of the neutral species, and the CH out-of-plane bends produce bands that are 5-20 times weaker than those of the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.

Fabrication of a Cryogenic Bias Filter for Ultrasensitive Focal Plane

NASA Technical Reports Server (NTRS)

Chervenak, James; Wollack, Edward

2012-01-01

A fabrication process has been developed for cryogenic in-line filtering for the bias and readout of ultrasensitive cryogenic bolometers for millimeter and submillimeter wavelengths. The design is a microstripline filter that cuts out, or strongly attenuates, frequencies (10 50 GHz) that can be carried by wiring staged at cryogenic temperatures. The filter must have 100-percent transmission at DC and low frequencies where the bias and readout lines will carry signal. The fabrication requires the encapsulation of superconducting wiring in a dielectric-metal envelope with precise electrical characteristics. Sufficiently thick insulation layers with high-conductivity metal layers fully surrounding a patterned superconducting wire in arrayable formats have been demonstrated. A degenerately doped silicon wafer has been chosen to provide a metallic ground plane. A metallic seed layer is patterned to enable attachment to the ground plane. Thick silicon dioxide films are deposited at low temperatures to provide tunable dielectric isolation without degrading the metallic seed layer. Superconducting wiring is deposited and patterned using microstripline filtering techniques to cut out the relevant frequencies. A low Tc superconductor is used so that it will attenuate power strongly above the gap frequency. Thick dielectric is deposited on top of the circuit, and then vias are patterned through both dielectric layers. A thick conductive film is deposited conformally over the entire circuit, except for the contact pads for the signal and bias attachments to complete the encapsulating ground plane. Filters are high-aspect- ratio rectangles, allowing close packing in one direction, while enabling the chip to feed through the wall of a copper enclosure. The chip is secured in the copper wall using a soft metal seal to make good thermal and electrical contact to the outer shield.

Study between anb angle and wits appraisal in cone beam computed tomography (cbct)

PubMed Central

Cibrián, Rosa; Gandia, Jose L.; Paredes, Vanessa

2013-01-01

Objectives: To analyse the ANB and Wits values and to study correlations between those two measurements and other measurements in diagnosing the anteroposterior maxilo-mandibular relationship with CBCT. Study Design: Ninety patients who had previously a CBCT (i-CAT®) as a diagnostic register were selected. A 3D cephalometry was designed using one software package, InVivo5®. This cephalometry included 3 planes of reference, 3 angle measurements and 1 linear measurement. The means and standard deviations of the mean of each measurement were assessed. After that, a Pearson´s correlation coefficient has been performed to analyse the significance of each relationship. Results: When classifying the sample according to the anteroposterior relationship, the values obtained of ANB (Class I: 53%; Class II: 37%; Class III: 10%) and Wits (Class I: 35%; Class II: 56%; Class III: 9%) did not coincide, except for the Class III group. However, of the patients classified differently (Class I and Class II patients) by ANB and Wits, a high percentage of individuals (n=22; 49%), had a mesofacial pattern with a mandibular plane angle within normal values. A correlation has been found between ANB and Wits (r=0,262), occlusal plane angle and ANB (r=0,426), and mandibular plane angle and Wits (r=0,242). No correlation was found between either Wits or ANB in relation with the age of the individuals. Conclusions: ANB and Wits must be included in 3D cephalometric analyses as both are necessary to undertake a more accurate diagnosis of the maxillo-mandibular relationship of the patients. Key words:Cone beam computed tomography, ANB, Wits, cephalometrics. PMID:23722136

High sensitivity pulse-counting mass spectrometer system for noble gas analysis

NASA Technical Reports Server (NTRS)

Hohenberg, C. M.

1980-01-01

A pulse-counting mass spectrometer is described which is comprised of a new ion source of cylindrical geometry, with exceptional optical properties (the Baur source), a dual focal plane externally adjustable collector slits, and a 17-stage Allen-type electron multiplier, all housed in a metal 21 cm radius, 90 deg magnetic sector flight tube. Mass discrimination of the instrument is less than 1 per mil per mass unit; the optical transmission is more than 90%; the source sensitivity (Faraday collection) is 4 ma/torr at 250 micron emission; and the abundance sensitivity is 30,000.

DSMC simulation of the interaction between rarefied free jets

NASA Technical Reports Server (NTRS)

Dagum, Leonardo; Zhu, S. H. K.

1993-01-01

This paper presents a direct simulation Monte Carlo (DSMC) calculation of two interacting free jets exhausting into vacuum. The computed flow field is compared against available experimental data and shows excellent agreement everywhere except in the very near field (less than one orifice diameter downstream of the jet exhaust plane). The lack of agreement in this region is attributed to having assumed an inviscid boundary condition for the orifice lip. The results serve both to validate the DSMC code for a very complex, three dimensional non-equilibrium flow field, and to provide some insight as to the complicated nature of this flow.

Features of sound propagation through and stability of a finite shear layer

NASA Technical Reports Server (NTRS)

Koutsoyannis, S. P.

1976-01-01

The plane wave propagation, the stability and the rectangular duct mode problems of a compressible inviscid linearly sheared parallel, but otherwise homogeneous flow, are shown to be governed by Whittaker's equation. The exact solutions for the perturbation quantities are essentially Whittaker M-functions. A number of known results are obtained as limiting cases of exact solutions. For the compressible finite thickness shear layer it is shown that no resonances and no critical angles exist for all Mach numbers, frequencies and shear layer velocity profile slopes except in the singular case of the vortex sheet.

Initial Results of Interdisciplinary Science Enabled by Eclipse 2017: NASA Perspective

NASA Astrophysics Data System (ADS)

Guhathakurta, M.

2017-12-01

The exceptionally long path over land of the August 21st total and partial solar eclipse provided an unprecedented opportunity for cross disciplinary studies of the sun, moon, Earth, and their interactions. NASA supported research using ground-based measurements, balloons and planes that "chased" the eclipse as well as data taken from a vast array of orbiting spacecraft, all of which helped scientists take continuous measurements of the sun and the effects of the eclipse on the ionosphere and Earth for relatively long periods of time. This talk will summarize some of the initial findings from these research.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, Min-Cherl; Zhang, Dongrong; Nikiforov, Gueorgui O.

Ultrathin (<6 nm) polycrystalline films of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-P) are deposited with a two-step spin-coating process. The influence of spin-coating conditions on morphology of the resulting film was examined by atomic force microscopy. Film thickness and RMS surface roughness were in the range of 4.0–6.1 and 0.6–1.1 nm, respectively, except for small holes. Polycrystalline structure was confirmed by grazing incidence x-ray diffraction measurements. Near-edge x-ray absorption fine structure measurements suggested that the plane through aromatic rings of TIPS-P molecules was perpendicular to the substrate surface.

MOS Circuitry Would Detect Low-Energy Charged Particles

NASA Technical Reports Server (NTRS)

Sinha, Mahadeva; Wadsworth, Mark

2003-01-01

Metal oxide semiconductor (MOS) circuits for measuring spatially varying intensities of beams of low-energy charged particles have been developed. These circuits are intended especially for use in measuring fluxes of ions with spatial resolution along the focal planes of mass spectrometers. Unlike prior mass spectrometer focal-plane detectors, these MOS circuits would not be based on ion-induced generation of electrons, and photons; instead, they would be based on direct detection of the electric charges of the ions. Hence, there would be no need for microchannel plates (for ion-to-electron conversion), phosphors (for electron-to-photon conversion), and photodetectors (for final detection) -- components that degrade spatial resolution and contribute to complexity and size. The developmental circuits are based on linear arrays of charge-coupled devices (CCDs) with associated readout circuitry (see figure). They resemble linear CCD photodetector arrays, except that instead of a photodetector, each pixel contains a capacitive charge sensor. The capacitor in each sensor comprises two electrodes (typically made of aluminum) separated by a layer of insulating material. The exposed electrode captures ions and accumulates their electric charges during signal-integration periods.

Spatial Orientation and Balance Control Changes Induced by Altered Gravito-Inertial Force Vectors in Vestibular Deficient Patients

NASA Technical Reports Server (NTRS)

Kaufman, Galen D.; Wood, Scott J.; Gianna, Claire C.; Black, F. Owen; Paloski, William H.

2000-01-01

Eight chronic vestibular deficient (VD) patients (bilateral N = 4, unilateral N = 4, ages 18-67 were exposed to an interaural centripetal acceleration of 1 G (resultant 45 degree roll tilt of 1.4 G) on a 0.8 meter radius centrifuge for up to 90 minutes in the dark. The patients sat with head fixed upright, except every 4 of 10 minutes when instructed to point their nose and eyes towards a visual target (switched on every 3 to 5 seconds at random places within plus or minus 30 deg) in the Earth horizontal plane. Eye movements, including directed saccades for subjective Earth-and head-referenced planes, were recorded before, during, and after centrifugation using electro-oculography. Postural sway was measured before and within ten minutes after centrifugation using a sway-referenced or earth-fixed support surface, and with or without a head movement sequence. The protocol was selected for each patient based on the most challenging condition in which the patient was able to maintain balance with eyes closed.

The most important physiological constants among the Volga region long-livers

NASA Astrophysics Data System (ADS)

Malinova, L. I.; Shuvalov, S. S.; Denisova, T. P.

2012-03-01

In our research we brought out the age difference in the group of long-livers and the continuous character of the biochemical basal metabolism indexes changing. The results allowed us to carry out the polynominal high-powered approximation to study the dynamics of laboratory indexes. We revealed the progressive reduction of the cholesterol, triglycerides, glucose and creatinine levels starting from 90 years of age, and this reduction showed the non-linear character with interchange of local minimums and maximums. During the speed characteristics analysis we revealed the cooccurrence of the speed maximums of all the examined biochemical indexes, except the speed of changing the concentration of cholesterol, which maximum took the lead over the other indexes by four years. The phase-plane portrait analysis of the regulatory systems on the plane "time - speed" showed the unfulfilled attempt of system stabilization by all the searched parameters nearby the special spot - "stable focus". The standard deviation values analysis of the researched parameters showed their progressive reduction in the long-livers. That fact can be considered as the regulatory systems physiological "backlash" reduction among the centenarians.

Unidirectional endotaxial cobalt di-silicide nanowires on Si(110) substrates

NASA Astrophysics Data System (ADS)

Mahato, J. C.; Das, Debolina; Banu, Nasrin; Satpati, Biswarup; Dev, B. N.

2017-10-01

Self-organized growth of well-ordered endotaxial silicide nanowires (NWs) on clean Si(110) surfaces has been investigated by in situ scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Co deposition on clean Si(110) reconstructed surfaces at ∼600 °C produces unidirectional CoSi2 NWs by reaction of cobalt with the hot silicon substrate. STM investigations reveal four major types of distinct NWs, all growing along the [-110] in-plane direction except one type growing along the in-plane [-113] direction. There are also some nanodots. The cross-sectional TEM measurements show that the unidirectional NWs are of two types—flat-top and ridged. The NWs grow not only on the substrate but also into the substrate. CoSi2 in flat top NWs are in the same crystallographic orientation as the substrate Si and the buried interfaces between CoSi2 and Si are A-type. In the ridged NWs CoSi2 and Si are in different crystallographic orientations and the interfaces are B-type. The ridged NWs are in general wider and grow deeper into the substrate.

Flexible printed circuit board actuators

NASA Astrophysics Data System (ADS)

Lee, Junseok; Cha, Youngsu

2017-12-01

Out-of-plane actuators are made possible by the breaking of planar symmetry. In this paper, we present a thin-film out-of-plane electrostatic actuator for a flexible printed circuit board (FPCB) that can be fabricated with a single step of the conventional manufacturing process. No other components are required for actuation except a single sheet of the FPCB, and it works based on the planar asymmetry resulting from asymmetrically patterned top and bottom electrodes on each side of the polyimide film. With the structural asymmetry, the application of a high voltage in the order of kilovolts results in the asymmetry of the electric fields and the body force density, which generates the bending moment that leads to macroscopic deformations. We applied the finite element method to examine the asymmetry induced by the difference in the electrodes. In the experiment, the displacement responses to step input and square wave input of various frequencies were analyzed. It was found that our actuator constitutes an underdamped system, exhibiting resonance characteristics. The maximum oscillatory amplitude was determined at resonance, and the relationship between the displacement and the applied voltage was investigated.

Design and Realization of a Planar Ultrawideband Antenna with Notch Band at 3.5 GHz

PubMed Central

2014-01-01

A small antenna with single notch band at 3.5 GHz is designed for ultrawideband (UWB) communication applications. The fabricated antenna comprises a radiating monopole element and a perfectly conducting ground plane with a wide slot. To achieve a notch band at 3.5 GHz, a parasitic element has been inserted in the same plane of the substrate along with the radiating patch. Experimental results shows that, by properly adjusting the position of the parasitic element, the designed antenna can achieve an ultrawide operating band of 3.04 to 11 GHz with a notched band operating at 3.31–3.84 GHz. Moreover, the proposed antenna achieved a good gain except at the notched band and exhibits symmetric radiation patterns throughout the operating band. The prototype of the proposed antenna possesses a very compact size and uses simple structures to attain the stop band characteristic with an aim to lessen the interference between UWB and worldwide interoperability for microwave access (WiMAX) band. PMID:25133245

Unidirectional endotaxial cobalt di-silicide nanowires on Si(110) substrates.

PubMed

Mahato, J C; Das, Debolina; Banu, Nasrin; Satpati, Biswarup; Dev, B N

2017-10-20

Self-organized growth of well-ordered endotaxial silicide nanowires (NWs) on clean Si(110) surfaces has been investigated by in situ scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Co deposition on clean Si(110) reconstructed surfaces at ∼600 °C produces unidirectional CoSi 2 NWs by reaction of cobalt with the hot silicon substrate. STM investigations reveal four major types of distinct NWs, all growing along the [-110] in-plane direction except one type growing along the in-plane [-113] direction. There are also some nanodots. The cross-sectional TEM measurements show that the unidirectional NWs are of two types-flat-top and ridged. The NWs grow not only on the substrate but also into the substrate. CoSi 2 in flat top NWs are in the same crystallographic orientation as the substrate Si and the buried interfaces between CoSi 2 and Si are A-type. In the ridged NWs CoSi 2 and Si are in different crystallographic orientations and the interfaces are B-type. The ridged NWs are in general wider and grow deeper into the substrate.

Influence of strain rate on the structure/property behavior of the alpha-2 alloy Ti-24.5Al-10.5Nb-1.5Mo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gray, G.T. III; Hong, Sun Ig; Marquardt, B.J.

Preliminary dislocation g{center_dot}b analysis revealed that following room temperature deformation at low strain rate the majority of the dislocations are a-dislocations lying on basal planes, 2nd order pyramidal (a/2 + c) slip on [1211], and 1st order pyramidal a-slip on [1011]. Increasing the rate of deformation at room temperature to 6000 s{sup {minus}1} is seen to result in increased a-slip on prism planes and a decreased amount of basal slip. At high-strain-rates and elevated temperatures the substructure was seen to be generally similar to that observed following high-rate deformation at room temperature except for an increased amount of basal slipmore » and a somewhat higher incidence of 2nd order pyramidal slip. The defect generation and the rate sensitivity of Ti-24.5Al-10.5Nb-1.5Mo are discussed as a function of strain rate and temperature and contrasted to that observed in conventional titanium alloys and TiAl.« less

The Solar Orbiter Heliospheric Imager (SoloHI) for the Solar Orbiter Mission

NASA Astrophysics Data System (ADS)

Howard, R.; Colaninno, R. C.; Plunkett, S. P.; Thernisien, A. F.; Wang, D.; Rich, N.; Korendyke, C.; Socker, D. G.; Linton, M.; McMullin, D. R.; Vourlidas, A.; Liewer, P. C.; De Jong, E.; Velli, M.; Mikic, Z.; Bothmer, V.; Philippe, L.; Carter, M. T.

2017-12-01

The SoloHI instrument has completed its development effort and has been integrated onto the Solar Orbiter (SolO) spacecraft. The SolO mission, scheduled for launch in February 2019, will undergo gravity assist maneuvers around Venus to change both the perihelion distance as well as the plane of the orbit to ultimately achieve a minimum perihelion of 0.28 AU and an orbital inclination of about 35° relative to the ecliptic plane. The remote sensing instruments will operate for three 10-day periods out of the nominal 6-month orbit. SoloHI will observe sunlight scattered by free electrons in the corona/solar wind from 5° to 45° elongation in visible wavelengths and will provide a coupling between remote sensing and in situ observations. It is very similar to the HI-1 instrument on STEREO/SECCHI except that the FOV is twice the size at 40o. We present our efforts to prepare for the mission including our observing plans, quick-look plans and some results of the calibration activities. We gratefully acknowledge the support of the NASA Solar Orbiter Collaboration project.

Application of numerical method in calculating the internal rate of return of joint venture investment using diminishing musyarakah model

NASA Astrophysics Data System (ADS)

Ruslan, Siti Zaharah Mohd; Jaffar, Maheran Mohd

2017-05-01

Islamic banking in Malaysia offers variety of products based on Islamic principles. One of the concepts is a diminishing musyarakah. The concept of diminishing musyarakah helps Muslims to avoid transaction which are based on riba. The diminishing musyarakah can be defined as an agreement between capital provider and entrepreneurs that enable entrepreneurs to buy equity in instalments where profits and losses are shared based on agreed ratio. The objective of this paper is to determine the internal rate of return (IRR) for a diminishing musyarakah model by applying a numerical method. There are several numerical methods in calculating the IRR such as by using an interpolation method and a trial and error method by using Microsoft Office Excel. In this paper we use a bisection method and secant method as an alternative way in calculating the IRR. It was found that the diminishing musyarakah model can be adapted in managing the performance of joint venture investments. Therefore, this paper will encourage more companies to use the concept of joint venture in managing their investments performance.

Gapped pulses for frequency-swept MRI

NASA Astrophysics Data System (ADS)

Idiyatullin, Djaudat; Corum, Curt; Moeller, Steen; Garwood, Michael

2008-08-01

A recently introduced method called SWIFT (SWeep Imaging with Fourier Transform) is a fundamentally different approach to MRI which is particularly well suited to imaging objects with extremely fast spin-spin relaxation rates. The method exploits a frequency-swept excitation pulse and virtually simultaneous signal acquisition in a time-shared mode. Correlation of the spin system response with the excitation pulse function is used to extract the signals of interest. With SWIFT, image quality is highly dependent on producing uniform and broadband spin excitation. These requirements are satisfied by using frequency-modulated pulses belonging to the hyperbolic secant family (HS n pulses). This article describes the experimental steps needed to properly implement HS n pulses in SWIFT. In addition, properties of HS n pulses in the rapid passage, linear region are investigated, followed by an analysis of the pulses after inserting the "gaps" needed for time-shared excitation and acquisition. Finally, compact expressions are presented to estimate the amplitude and flip angle of the HS n pulses, as well as the relative energy deposited by the SWIFT sequence.

Longitudinal and bulk viscosities of Lennard-Jones fluids

NASA Astrophysics Data System (ADS)

Tankeshwar, K.; Pathak, K. N.; Ranganathan, S.

1996-12-01

Expressions for the longitudinal and bulk viscosities have been derived using Green Kubo formulae involving the time integral of the longitudinal and bulk stress autocorrelation functions. The time evolution of stress autocorrelation functions are determined using the Mori formalism and a memory function which is obtained from the Mori equation of motion. The memory function is of hyperbolic secant form and involves two parameters which are related to the microscopic sum rules of the respective autocorrelation function. We have derived expressions for the zeroth-, second-and fourth- order sum rules of the longitudinal and bulk stress autocorrelation functions. These involve static correlation functions up to four particles. The final expressions for these have been put in a form suitable for numerical calculations using low- order decoupling approximations. The numerical results have been obtained for the sum rules of longitudinal and bulk stress autocorrelation functions. These have been used to calculate the longitudinal and bulk viscosities and time evolution of the longitudinal stress autocorrelation function of the Lennard-Jones fluids over wide ranges of densities and temperatures. We have compared our results with the available computer simulation data and found reasonable agreement.

Boattail juncture shaping for spin-stabilized rounds in supersonic flight

NASA Astrophysics Data System (ADS)

Jiajan, W.; Chue, R. S. M.; Nguyen, T.; Yu, S. C. M.

2015-03-01

In this paper, the effects of boattail junction shaping on aerodynamic drag and stability of supersonic spin-stabilized rounds are investigated using computational fluid dynamics. For a generic round body comprising of a secant-ogive nose, a cylindrical body and a conical boattail, the shaping technique was achieved by adding a convex surface of varying degrees of radius of curvature to the junction between the cylindrical body and the boattail. It was shown through numerical simulations that this shaping technique can provide a reduction in aerodynamic drag of up to 5.4 % without destabilizing the round bodies when the radius of curvature is less than 8.8 times the diameter of the cylindrical body. The more gradual change of the flow characteristics, e.g., the pressure over the convex surface, was identified as the main reason for the drag reduction. A unique aspect of the current work is that stability is treated as an integral part of the performance assessment. It was also found that the dynamic instability encountered at large radii of curvature is due to the Magnus effects.

Predicting the effect of relaxation during frequency-selective adiabatic pulses

NASA Astrophysics Data System (ADS)

Pfaff, Annalise R.; McKee, Cailyn E.; Woelk, Klaus

2017-11-01

Adiabatic half and full passages are invaluable for achieving uniform, B1-insensitive excitation or inversion of macroscopic magnetization across a well-defined range of NMR frequencies. To accomplish narrow frequency ranges with adiabatic pulses (<100 Hz), long pulse durations at low RF power levels are necessary, and relaxation during these pulses may no longer be negligible. A numerical, discrete recursive combination of the Bloch equations for longitudinal and transverse relaxation with the optimized equation for adiabatic angular motion of magnetization is used to calculate the trajectory of magnetization including its relaxation during adiabatic hyperbolic secant pulses. The agreement of computer-calculated data with experimental results demonstrates that, in non-viscous, small-molecule fluids, it is possible to model magnetization and relaxation by considering standard T1 and T2 relaxation in the traditional rotating frame. The proposed model is aimed at performance optimizations of applications in which these pulses are employed. It differs from previous reports which focused on short high-power adiabatic pulses and relaxation that is governed by dipole-dipole interactions, cross polarization, or chemical exchange.

A 3D-Printable Polymer-Metal Soft-Magnetic Functional Composite-Development and Characterization.

PubMed

Khatri, Bilal; Lappe, Karl; Noetzel, Dorit; Pursche, Kilian; Hanemann, Thomas

2018-01-25

In this work, a 3D printed polymer-metal soft-magnetic composite was developed and characterized for its material, structural, and functional properties. The material comprises acrylonitrile butadiene styrene (ABS) as the polymer matrix, with up to 40 vol. % stainless steel micropowder as the filler. The composites were rheologically analyzed and 3D printed into tensile and flexural test specimens using a commercial desktop 3D printer. Mechanical characterization revealed a linearly decreasing trend of the ultimate tensile strength (UTS) and a sharp decrease in Young's modulus with increasing filler content. Four-point bending analysis showed a decrease of up to 70% in the flexural strength of the composite and up to a two-factor increase in the secant modulus of elasticity. Magnetic hysteresis characterization revealed retentivities of up to 15.6 mT and coercive forces of up to 4.31 kA/m at an applied magnetic field of 485 kA/m. The composite shows promise as a material for the additive manufacturing of passive magnetic sensors and/or actuators.

A 3D-Printable Polymer-Metal Soft-Magnetic Functional Composite—Development and Characterization

PubMed Central

Lappe, Karl; Noetzel, Dorit; Pursche, Kilian; Hanemann, Thomas

2018-01-01

In this work, a 3D printed polymer–metal soft-magnetic composite was developed and characterized for its material, structural, and functional properties. The material comprises acrylonitrile butadiene styrene (ABS) as the polymer matrix, with up to 40 vol. % stainless steel micropowder as the filler. The composites were rheologically analyzed and 3D printed into tensile and flexural test specimens using a commercial desktop 3D printer. Mechanical characterization revealed a linearly decreasing trend of the ultimate tensile strength (UTS) and a sharp decrease in Young’s modulus with increasing filler content. Four-point bending analysis showed a decrease of up to 70% in the flexural strength of the composite and up to a two-factor increase in the secant modulus of elasticity. Magnetic hysteresis characterization revealed retentivities of up to 15.6 mT and coercive forces of up to 4.31 kA/m at an applied magnetic field of 485 kA/m. The composite shows promise as a material for the additive manufacturing of passive magnetic sensors and/or actuators. PMID:29370112

Misalignment Effect Function Measurement for Oblique Rotation Axes: Counterintuitive Predictions and Theoretical Extensions

NASA Technical Reports Server (NTRS)

Ellis, Stephen R.; Adelstein, Bernard D.; Yeom, Kiwon

2013-01-01

The Misalignment Effect Function (MEF) describes the decrement in manual performance associated with a rotation between operators' visual display frame of reference and that of their manual control. It now has been empirically determined for rotation axes oblique to canonical body axes and is compared with the MEF previously measured for rotations about canonical axes. A targeting rule, called the Secant Rule, based on these earlier measurements is derived from a hypothetical process and shown to describe some of the data from three previous experiments. It explains the motion trajectories determined for rotations less than 65deg in purely kinematic terms without the need to appeal to a mental rotation process. Further analysis of this rule in three dimensions applied to oblique rotation axes leads to a somewhat surprising expectation that the difficulty posed by rotational misalignment should get harder as the required movement is shorter. This prediction is confirmed. Geometry underlying this rule also suggests analytic extensions for predicting more generally the difficulty of making movements in arbitrary directions subject to arbitrary misalignments.

Static current-sheet models of quiescent prominences

NASA Technical Reports Server (NTRS)

Wu, F.; Low, B. C.

1986-01-01

A particular class of theoretical models idealize the prominence to be a discrete flat electric-current sheet suspended vertically in a potential magnetic field. The weight of the prominence is supported by the Lorentz force in the current sheet. These models can be extended to have curved electric-current sheets and to vary three-dimensionally. The equation for force balance is 1 over 4 pi (del times B) times Bdel p- p9 z=zero. Using Cartesian coordinates we take, for simplicity, a uniform gravity with constant acceleration g in the direction -z. If we are interested not in the detailed internal structure of the prominence, but in the global magnetic configuration around the prominence, we may take prominence plasma to be cold. Consideration is given to how such equilibrium states can be constructed. To simplify the mathematical problem, suppose there is no electric current in the atmosphere except for the discrete currents in the cold prominence sheet. Let us take the plane z =0 to be the base of the atmosphere and restrict our attention to the domain z greater than 0. The task we have is to solve for a magnetic field which is everywhere potential except on some free surface S, subject to suit able to boundary conditions. The surface S is determined by requiring that it possesses a discrete electric current density such that the Lorentz force on it is everywhere vertically upward to balance the weight of the material m(S). Since the magnetic field is potential in the external atmosphere, the latter is decoupled from the magnetic field and its plane parallel hydrostatic pressure and density can be prescribed.

Static current-sheet models of quiescent prominences

NASA Astrophysics Data System (ADS)

Wu, F.; Low, B. C.

1986-12-01

A particular class of theoretical models idealize the prominence to be a discrete flat electric-current sheet suspended vertically in a potential magnetic field. The weight of the prominence is supported by the Lorentz force in the current sheet. These models can be extended to have curved electric-current sheets and to vary three-dimensionally. The equation for force balance is 1 over 4 pi (del times B) times Bdel p- p9 z=zero. Using Cartesian coordinates we take, for simplicity, a uniform gravity with constant acceleration g in the direction -z. If we are interested not in the detailed internal structure of the prominence, but in the global magnetic configuration around the prominence, we may take prominence plasma to be cold. Consideration is given to how such equilibrium states can be constructed. To simplify the mathematical problem, suppose there is no electric current in the atmosphere except for the discrete currents in the cold prominence sheet. Let us take the plane z =0 to be the base of the atmosphere and restrict our attention to the domain z greater than 0. The task we have is to solve for a magnetic field which is everywhere potential except on some free surface S, subject to suit able to boundary conditions. The surface S is determined by requiring that it possesses a discrete electric current density such that the Lorentz force on it is everywhere vertically upward to balance the weight of the material m(S). Since the magnetic field is potential in the external atmosphere, the latter is decoupled from the magnetic field and its plane parallel hydrostatic pressure and density can be prescribed.

Preliminary Heat-Transfer Measurements on a Hypersonic Glide Configuration Having 79.5 degree Sweepback and 45 degree Dihedral at a Mach Number of 4.95

NASA Technical Reports Server (NTRS)

Stainback, Calvin

1960-01-01

An experimental investigation was conducted to evaluate the heat-transfer characteristics of a hypersonic glide configuration having 79.5 deg of sweepback (measured in the plane of the leading edges) and 45 of dihedral. The tests were conducted at a nominal Mach number of 4.95 and a stagnation temperature of 400 F. The test-section unit Reynolds number was varied from 1.95 x 10(exp 6) to 12.24 x 10(exp 6) per foot. The results indicated that the laminar-flow heat-transfer rate to the lower surface of the model decreased as the distance from the ridge line increased except for thermocouples located near the semispan at an angle of attack of 00 with respect to the plane of the leading edges. The heat-transfer distribution (local heating rate relative to the ridge-line heating rate) was similar to the theoretical heat-transfer distribution for a two-dimensional blunt body, if the ridge line was assumed to be the stagnation line, and could be predicted by this theory provided a modified Newtonian pressure distribution was used. Except in the vicinity of the apex, the ridge-line heat-transfer rate could also be predicted from two-dimensional blunt-body heat-transfer theory provided it was assumed that the stagnation-line heat-transfer rate varied as the cosine of the effective sweep (sine of the angle of attack of the ridge line). The heat-transfer level on the lower surface and the nondimensional heat-transfer distribution around the body on the lower surface were in qualitative agreement with the results of a geometric study of highly swept delta wings with large positive dihedrals made in reference 1.

Scaled plane-wave Born cross sections for atoms and molecules

NASA Astrophysics Data System (ADS)

Tanaka, H.; Brunger, M. J.; Campbell, L.; Kato, H.; Hoshino, M.; Rau, A. R. P.

2016-04-01

Integral cross sections for optically allowed electronic-state excitations of atoms and molecules by electron impact, by applying scaled plane-wave Born models, are reviewed. Over 40 years ago, Inokuti presented an influential review of charged-particle scattering, based on the theory pioneered by Bethe forty years earlier, which emphasized the importance of reliable cross-section data from low eV energies to high keV energies that are needed in many areas of radiation science with applications to astronomy, plasmas, and medicine. Yet, with a couple of possible exceptions, most computational methods in electron-atom scattering do not, in general, overlap each other's validity range in the region from threshold up to 300 eV and, in particular, in the intermediate region from 30 to 300 eV. This is even more so for electron-molecule scattering. In fact this entire energy range is of great importance and, to bridge the gap between the two regions of low and high energy, scaled plane-wave Born models were developed to provide reliable, comprehensive, and absolute integral cross sections, first for ionization by Kim and Rudd and then extended to optically allowed electronic-state excitation by Kim. These and other scaling models in a broad, general application to electron scattering from atoms and molecules, their theoretical basis, and their results for cross sections along with comparison to experimental measurements are reviewed. Where possible, these data are also compared to results from other computational approaches.

Report: Potential environmental impact of exempt site materials - a case study of bituminous road planings and waste soils.

PubMed

Bark, Marjorie; Bland, Michael; Grimes, Sue

2009-09-01

The use of waste materials for ecological benefit, agricultural improvement or as part of construction works are often exempt from waste management control in order to maximize the reuse of material that would otherwise be disposed of to landfill. It is important, however, to determine whether there is potential for such waste to cause environmental harm in the context of the basis for granting exemptions under the relevant framework objective to ensure that waste is recovered or disposed of without risk to water, air, soil, plants or animals. The potential for environmental harm was investigated by leaching studies on two wastes commonly found at exempt sites: bituminous road planings and waste soils. For bituminous road planings, the organic components of the waste were identified by their solubility in organic solvents but these components would have low environmental impact in terms of bioavailability. Leaching studies of the heavy metals copper, lead and zinc, into the environment, under specific conditions and particularly those modelling acid rain and landfill leachate conditions showed that, except for copper, the amounts leached fell within Waste Acceptance Criteria compliance limits for defining waste as inert waste. The fact that the amount of copper leached was greater than the Waste Acceptance Criteria level suggests that either additional testing of wastes regarded as exempt should be carried out to ensure that they are in analytical compliance or that legislation should allow for the potential benefits of reuse to supersede deviations from analytical compliance.

Comparison of Lower Limb Segments Kinematics in a Taekwondo Kick. An Approach to the Proximal to Distal Motion

PubMed Central

Estevan, Isaac; Falco, Coral; Silvernail, Julia Freedman; Jandacka, Daniel

2015-01-01

In taekwondo, there is a lack of consensus about how the kick sequence occurs. The aim of this study was to analyse the peak velocity (resultant and value in each plane) of lower limb segments (thigh, shank and foot), and the time to reach this peak velocity in the kicking lower limb during the execution of the roundhouse kick technique. Ten experienced taekwondo athletes (five males and five females; mean age of 25.3 ±5.1 years; mean experience of 12.9 ±5.3 years) participated voluntarily in this study performing consecutive kicking trials to a target located at their sternum height. Measurements for the kinematic analysis were performed using two 3D force plates and an eight camera motion capture system. The results showed that the proximal segment reached a lower peak velocity (resultant and in each plane) than distal segments (except the peak velocity in the frontal plane where the thigh and shank presented similar values), with the distal segment taking the longest to reach this peak velocity (p < 0.01). Also, at the instant every segment reached the peak velocity, the velocity of the distal segment was higher than the proximal one (p < 0.01). It provides evidence about the sequential movement of the kicking lower limb segments. In conclusion, during the roundhouse kick in taekwondo inter-segment motion seems to be based on a proximo-distal pattern. PMID:26557189

Comparison of Lower Limb Segments Kinematics in a Taekwondo Kick. An Approach to the Proximal to Distal Motion.

PubMed

Estevan, Isaac; Falco, Coral; Silvernail, Julia Freedman; Jandacka, Daniel

2015-09-29

In taekwondo, there is a lack of consensus about how the kick sequence occurs. The aim of this study was to analyse the peak velocity (resultant and value in each plane) of lower limb segments (thigh, shank and foot), and the time to reach this peak velocity in the kicking lower limb during the execution of the roundhouse kick technique. Ten experienced taekwondo athletes (five males and five females; mean age of 25.3 ±5.1 years; mean experience of 12.9 ±5.3 years) participated voluntarily in this study performing consecutive kicking trials to a target located at their sternum height. Measurements for the kinematic analysis were performed using two 3D force plates and an eight camera motion capture system. The results showed that the proximal segment reached a lower peak velocity (resultant and in each plane) than distal segments (except the peak velocity in the frontal plane where the thigh and shank presented similar values), with the distal segment taking the longest to reach this peak velocity (p < 0.01). Also, at the instant every segment reached the peak velocity, the velocity of the distal segment was higher than the proximal one (p < 0.01). It provides evidence about the sequential movement of the kicking lower limb segments. In conclusion, during the roundhouse kick in taekwondo inter-segment motion seems to be based on a proximo-distal pattern.

Ten thousand cloud makers: Is airplane exhaust altering earth`s climate?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monastersky, R.

1996-07-06

The small Saberliner jet carrying Bruce E. Anderson rolled almost completely upside down, when his plane entered the wake of a DC-8 jet just a few miles ahead. The backwash-a tight horizontal tornado whirling at more than 100 miles per hour-spun the light Saberliner 140{degrees} and sent it into a dive, causing Anderson, his food, and everything else in the plane to go temporarily weightless. When they recovered, they nosed up behind the DC-8 for some more punishment. Although it sounds like military flight training, Anderson and his colleagues were actually conducting a high-tech emissions check-measuring the gases and particlesmore » spewing out of jet engines. Their mission resembles the pollution tests that states routinely perform on cars, except that the NASA-run experiment happened at 400 miles per hour, 40,000 feet above the ground. And whereas car emissions are well understood, scientists have little information on the pollution from jet engines. Toward that end, NASA gathered four planes and 120 scientists in Kansas during April and May to make the most detailed measurements yet of jet engine exhaust at cruising altitude. This project and future ones are addressing the question of whether aircraft emissions are increasing the number of clouds and are perturbing atmospheric chemistry, both of which could affect weather on earth. This article describes the project, what lead to it, what has been learned and where it is going in the future.« less

Classification of the line-soliton solutions of KPII

NASA Astrophysics Data System (ADS)

Chakravarty, Sarbarish; Kodama, Yuji

2008-07-01

In the previous papers (notably, Kodama Y 2004 J. Phys. A: Math. Gen. 37 11169-90, Biondini G and Chakravarty S 2006 J. Math. Phys. 47 033514), a large variety of line-soliton solutions of the Kadomtsev-Petviashvili II (KPII) equation was found. The line-soliton solutions are solitary waves which decay exponentially in the (x, y)-plane except along certain rays. In this paper, it is shown that those solutions are classified by asymptotic information of the solution as |y| → ∞. The present work then unravels some interesting relations between the line-soliton classification scheme and classical results in the theory of permutations.

Multiple jet study

NASA Technical Reports Server (NTRS)

Walker, R. E.; Kors, D. L.

1973-01-01

Test data is presented which allows determination of jet penetration and mixing of multiple cold air jets into a ducted subsonic heated mainstream flow. Jet-to-mainstream momentum flux ratios ranged from 6 to 60. Temperature profile data is presented at various duct locations up to 24 orifice diameters downstream of the plane of jet injection. Except for two configurations, all geometries investigated had a single row of constant diameter orifices located transverse to the main flow direction. Orifice size and spacing between orifices were varied. Both of these were found to have a significant effect on jet penetration and mixing. The best mixing of the hot and cold streams was achieved with duct height.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, Benjamin S.

The Futility package contains the following: 1) Definition of the size of integers and real numbers; 2) A generic Unit test harness; 3) Definitions for some basic extensions to the Fortran language: arbitrary length strings, a parameter list construct, exception handlers, command line processor, timers; 4) Geometry definitions: point, line, plane, box, cylinder, polyhedron; 5) File wrapper functions: standard Fortran input/output files, Fortran binary files, HDF5 files; 6) Parallel wrapper functions: MPI, and Open MP abstraction layers, partitioning algorithms; 7) Math utilities: BLAS, Matrix and Vector definitions, Linear Solver methods and wrappers for other TPLs (PETSC, MKL, etc), preconditioner classes;more » 8) Misc: random number generator, water saturation properties, sorting algorithms.« less

Features of sound propagation through and stability of a finite shear layer

NASA Technical Reports Server (NTRS)

Koutsoyannis, S. P.

1977-01-01

The plane wave propagation, the stability, and the rectangular duct mode problems of a compressible, inviscid, linearly sheared, parallel, homogeneous flow are shown to be governed by Whittaker's equation. The exact solutions for the perturbation quantities are essentially the Whittaker M-functions where the nondimensional quantities have precise physical meanings. A number of known results are obtained as limiting cases of the exact solutions. For the compressible finite thickness shear layer it is shown that no resonances and no critical angles exist for all Mach numbers, frequencies, and shear layer velocity profile slopes except in the singular case of the vortex sheet.

Surface plasmons for doped graphene

NASA Astrophysics Data System (ADS)

Bordag, M.; Pirozhenko, I. G.

2015-04-01

Within the Dirac model for the electronic excitations of graphene, we calculate the full polarization tensor with finite mass and chemical potential. It has, besides the (00)-component, a second form factor, which must be accounted for. We obtain explicit formulas for both form factors and for the reflection coefficients. Using these, we discuss the regions in the momentum-frequency plane where plasmons may exist and give numeric solutions for the plasmon dispersion relations. It turns out that plasmons exist for both, transverse electric and transverse magnetic polarizations over the whole range of the ratio of mass to chemical potential, except for zero chemical potential, where only a TE plasmon exists.

Recent progress on exploring exceptionally high and anisotropic H+/OH– ion conduction in two-dimensional materials

PubMed Central

Sun, Pengzhan; Sasaki, Takayoshi

2017-01-01

Ion conducting membranes/electrolytes have been employed extensively in some important industrial and biological systems, especially in fuel cells, water electrolyzers, gas separation, sensors and biological selective ion transport, acting as one of the core components and sometimes directly determining the device performance. However, the traditional polymeric proton exchange membranes (PEMs)/anion exchange membranes (AEMs) suffer from highly toxic preparation procedures, poor thermal and chemical stabilities, and unsatisfactory ion conductivities. This has triggered researchers worldwide to explore alternative inorganic building blocks with high ion conductivities and stabilities from the new materials library, hoping to solve the above long-lasting problems. The recent burgeoning research on two-dimensional (2D) materials has unveiled exceptionally high ionic conductivities, which raises the feasibility of fabricating high-performance nanosheet-based ion conductors/membranes. In this perspective, the recent advances in measuring and understanding the exceptionally high and anisotropic H+/OH– ion conductivities of representative 2D materials, e.g. graphene oxide (GO), vermiculite and layered double hydroxide (LDH) nanosheets, are reviewed. In particular, regarding the anisotropic ionic conduction in 2D nanosheets, possible design strategies and technological innovations for fabricating macroscopic nanosheet-based ionic conductors/membranes are proposed for maximizing the high in-plane conduction, which may serve to guide future development of high-performance industrial and biological systems relying on H+/OH– conducting membranes. PMID:29629071

Recent progress on exploring exceptionally high and anisotropic H+/OH- ion conduction in two-dimensional materials.

PubMed

Sun, Pengzhan; Ma, Renzhi; Sasaki, Takayoshi

2018-01-07

Ion conducting membranes/electrolytes have been employed extensively in some important industrial and biological systems, especially in fuel cells, water electrolyzers, gas separation, sensors and biological selective ion transport, acting as one of the core components and sometimes directly determining the device performance. However, the traditional polymeric proton exchange membranes (PEMs)/anion exchange membranes (AEMs) suffer from highly toxic preparation procedures, poor thermal and chemical stabilities, and unsatisfactory ion conductivities. This has triggered researchers worldwide to explore alternative inorganic building blocks with high ion conductivities and stabilities from the new materials library, hoping to solve the above long-lasting problems. The recent burgeoning research on two-dimensional (2D) materials has unveiled exceptionally high ionic conductivities, which raises the feasibility of fabricating high-performance nanosheet-based ion conductors/membranes. In this perspective, the recent advances in measuring and understanding the exceptionally high and anisotropic H + /OH - ion conductivities of representative 2D materials, e.g. graphene oxide (GO), vermiculite and layered double hydroxide (LDH) nanosheets, are reviewed. In particular, regarding the anisotropic ionic conduction in 2D nanosheets, possible design strategies and technological innovations for fabricating macroscopic nanosheet-based ionic conductors/membranes are proposed for maximizing the high in-plane conduction, which may serve to guide future development of high-performance industrial and biological systems relying on H + /OH - conducting membranes.

Expression of emotion in the kinematics of locomotion.

PubMed

Barliya, Avi; Omlor, Lars; Giese, Martin A; Berthoz, Alain; Flash, Tamar

2013-03-01

Here, we examine how different emotions-happiness, fear, sadness and anger-affect the kinematics of locomotion. We focus on a compact representation of locomotion properties using the intersegmental law of coordination (Borghese et al. in J Physiol 494(3):863-879, 1996), which states that, during the gait cycle of human locomotion, the elevation angles of the thigh, shank and foot do not evolve independently of each other but form a planar pattern of co-variation. This phenomenon is highly robust and has been extensively studied. The orientation of the plane has been correlated with changes in the speed of locomotion and with reduction in energy expenditure as speed increases. An analytical model explaining the conditions underlying the emergence of this plane and predicting its orientation reveals that it suffices to examine the amplitudes of the elevation angles of the different segments along with the phase shifts between them (Barliya et al. in Exp Brain Res 193:371-385, 2009). We thus investigated the influence of different emotions on the parameters directly determining the orientation of the intersegmental plane and on the angular rotation profiles of the leg segments, examining both the effect of changes in walking speed and effects independent of speed. Subjects were professional actors and naïve subjects with no training in acting. As expected, emotions were found to strongly affect the kinematics of locomotion, particularly walking speed. The intersegmental coordination patterns revealed that emotional expression caused additional modifications to the locomotion patterns that could not be explained solely by a change in speed. For all emotions except sadness, the amplitude of thigh elevation angles changed from those in neutral locomotion. The intersegmental plane was also differently oriented, especially during anger. We suggest that, while speed is the dominant variable allowing discrimination between different emotional gaits, emotion can be reliably recognized in locomotion only when speed is considered together with these kinematic changes.

Investigation of Three-Dimensional Stress Fields and Slip Systems for FCC Single Crystal Superalloy Notched Specimens

NASA Technical Reports Server (NTRS)

Arakere, Nagaraj K.; Magnan, Shannon; Ebrahimi, Fereshteh; Ferroro, Luis

2004-01-01

Metals and their alloys, except for a few intermetallics, are inherently ductile, i.e. plastic deformation precedes fracture in these materials. Therefore, resistance to fracture is directly related to the development of the plastic zone at the crack tip. Recent studies indicate that the fracture toughness of single crystals depends on the crystallographic orientation of the notch as well as the loading direction. In general, the dependence of crack propagation resistance on crystallographic orientation arises from the anisotropy of (i) elastic constants, (ii) plastic deformation (or slip), and (iii) the weakest fracture planes (e.g. cleavage planes). Because of the triaxial stress state at the notch tips, many slip systems that otherwise would not be activated during uniaxial testing, become operational. The plastic zone formation in single crystals has been tackled theoretically by Rice and his co-workers and only limited experimental work has been conducted in this area. The study of the stresses and strains in the vicinity of a FCC single crystal notch tip is of relatively recent origin. We present experimental and numerical investigation of 3D stress fields and evolution of slip sector boundaries near notches in FCC single crystal tension test specimens, and demonstrate that a 3D linear elastic finite element model that includes the effect of material anisotropy is shown to predict active slip planes and sectors accurately. The slip sector boundaries are shown to have complex curved shapes with several slip systems active simultaneously near the notch. Results are presented for surface and mid-plane of the specimens. The results demonstrate that accounting for 3D elastic anisotropy is very important for accurate prediction of slip activation near FCC single crystal notches loaded in tension. Results from the study will help establish guidelines for fatigue damage near single crystal notches.

Spherocylindrical microplane constitutive model for shale and other anisotropic rocks

NASA Astrophysics Data System (ADS)

Li, Cunbao; Caner, Ferhun C.; Chau, Viet T.; Bažant, Zdeněk P.

2017-06-01

Constitutive equations for inelastic behavior of anisotropic materials have been a challenge for decades. Presented is a new spherocylindrical microplane constitutive model that meets this challenge for the inelastic fracturing behavior of orthotropic materials, and particularly the shale, which is transversely isotropic and is important for hydraulic fracturing (aka fracking) as well as many geotechnical structures. The basic idea is to couple a cylindrical microplane system to the classical spherical microplane system. Each system is subjected to the same strain tensor while their stress tensors are superposed. The spherical phase is similar to the previous microplane models for concrete and isotropic rock. The integration of stresses over spherical microplanes of all spatial orientations relies on the previously developed optimal Gaussian integration over a spherical surface. The cylindrical phase, which is what creates the transverse isotropy, involves only microplanes that are normal to plane of isotropy, or the bedding layers, and enhance the stiffness and strength in that plane. Unlike all the microplane models except the spectral one, the present one can reproduce all the five independent elastic constants of transversely isotropic shales. Vice versa, from these constants, one can easily calculate all the microplane elastic moduli, which are all positive if the elastic in-to-out-of plane moduli ratio is not too big (usually less than 3.75, which applies to all shales). Oriented micro-crack openings, frictional micro-slips and bedding plane behavior can be modeled more intuitively than with the spectral approach. Data fitting shows that the microplane resistance depends on the angle with the bedding layers non-monotonically, and compressive resistance reaches a minimum at 60°. A robust algorithm for explicit step-by-step structural analysis is formulated. Like all microplane models, there are many material parameters, but they can be identified sequentially. Finally, comparisons with extensive test data for shale validate the model.

Use of dimensionality to enhance tunable microwave dielectrics

NASA Astrophysics Data System (ADS)

Schlom, D. G.; Lee, Che-Hui; Haislmaier, R.; Vlahos, E.; Gopalan, V.; Birol, T.; Zhu, Y.; Kourkoutis, L. F.; Benedek, N.; Kim, Y.; Brock, J. D.; Muller, D. A.; Fennie, C. J.; Orloff, N. D.; Booth, J. C.; Goian, V.; Kamba, S.; Biegalski, M. D.; Bernhagen, M.; Uecker, R.; Xi, X. X.; Takeuchi, I.

2012-02-01

The miniaturization and integration of frequency-agile microwave circuits---tunable filters, resonators, phase shifters and more---with microelectronics offers tantalizing device possibilities, yet requires thin films whose dielectric constant at GHz frequencies can be tuned by applying a quasi-static electric field. Appropriate systems, e.g., BaxSr1-xTiO3, have a paraelectric-to-ferroelectric transition just below ambient temperature, providing high tunability. Unfortunately such films suffer significant losses arising from defects. Recognizing that progress is stymied by dielectric loss, we start with a system with exceptionally low loss---Srn+1TinO3n+1 phases---where in-plane crystallographic shear (SrO)2 faults provide an alternative to point defects for accommodating non-stoichiometry. In this talk we will establish both experimentally and theoretically the emergence of a ferroelectric and highly tunable ground state in biaxially strained Srn+1TinO3n+1 phases with n>=3 at frequencies up to 40 GHz. With increasing n the (SrO)2 faults are separated further than the ferroelectric coherence length perpendicular to the in-plane polarization, enabling tunability with a figure of merit at room temperature that rivals all known tunable microwave dielectrics.

Analysis of QRS loop changes in the beat-to-beat Vectocardiogram of ischemic patients undergoing PTCA.

PubMed

Correa, Raul; Laciar, Eric; Arini, Pedro; Jane, Raimon

2009-01-01

In the present work, we have studied dynamic changes of QRS loop in the Vectocardiogram (VCG) of 80 patients that underwent Percutaneous Transluminal Coronary Angioplasty (PTCA). The VCG was obtained for each patient using the XYZ orthogonal leads of their electrocardiographic (ECG) records acquired before, during and after PTCA procedure. In order to analyze the variations of VCG, it has been proposed in this study the following parameters a) Maximum module of the cardiac depolarization vector, b) Volume, c) and Area of vectocardiographic loop corresponding to the QRS complex of each beat, d) Maximum distance between Centroid and the Loop, e) Angle between the XY plane and the Optimum Plane, f) Relation between the Area and Perimeter. The results obtained indicate that the parameters proposed show significant statistics differences (p-value<0.05) before, during (with some exceptions at the first minute of balloon inflation) and after PTCA. We conclude that the variations observed in the proposed parameters correctly represent not only the morphological changes in the depolarization VCG but also they reflect the modifications in the levels of cardiac ischemia induced by PTCA.

The efficacy of proanthocyanidins and secnidazole in the treatment of chronic periodontitis after scaling and root planing therapy.

PubMed

Li, M; Li, R; Jin, Q; Pang, J; Xu, Z

2017-01-01

The aim of this study is to evaluate the clinical and microbiological effect of the systemic antibiotic therapy of proanthocyanidins and secnidazole on periodontitis. Seventy-five subjects with chronic periodontitis were randomly divided into two treatment groups (secnidazole or proanthocyanidins) and one placebo control group (25 cases each). Plaque index (PI), gingival index (GI), gingival bleeding index (BI), probing pocket depth (PPD), and clinical attachment level (CAL) were carried out at baseline, post-treatment and 3 months after treatment. Microbial analysis was performed at baseline and post-treatment. The results show that the two treatment groups had greater mean reduction in BI, GI, and PPD evaluated at both post-treatment and 3 months after treatment compared to the control group (p less than 0.05), but there were no significant differences in those of PI and CAL (except CAL evaluated at post-treatment, p 0.05). After treatment, culturable bacteria counts significantly decreased. In conclusion, the adjunctive use of proanthocyanidins or secnidazole in combination with scaling and root planing in adults with periodontitis is effective in reducing the pathogenic flora and achieves significantly better clinical results to a certain degree.

[Actual relevance of Pauwels' classification of femoral neck fractures--a critical review].

PubMed

Schwarz, N

2010-03-01

The aim of this study was to evaluate the validity of Pauwels' classification of femoral neck fractures. A study of literature was performed. It has never been proven that the inclination of the fracture plane has a prognostic relevance. A number of papers prove the contrary, there are no publications where Pauwels' classification has been used successfully in selecting treatment modalities. Pauwels' theory of fracture inclination angle has not been transferred into clinical practice. This discrepancy probably goes back to the fact that the angle cannot be determined preoperatively, that in the majority of femoral neck fractures the angle is within the range of 40 to 60 degrees, that the theoretical angle variations do practically not exist, and that the shearing forces are reduced to an unknown amount by friction resistance due to the uneven fracture plane. The mechanical laws of the pseudarthrosis of the femoral neck cannot be extrapolated to acute fractures. The theory of Pauwels has apparently no clinical relevance for the majority of acute fractures, except for the rare transcervical fractures, and should not be considered any longer as a classification of acute femoral neck fractures due to the lack of prognostic and therapeutic relevance.

Three-dimensional reconstruction of vessels with stenoses and aneurysms from dual biplane angiograms

NASA Astrophysics Data System (ADS)

Fessler, Jeffrey A.; Macovski, Albert

1989-05-01

Parametric model-based approaches to 3-D reconstruction of vessels overcome the inherent problem of underdeterminancy in reconstruction from limited views by incorporating a priori knowledge about the structure of vessels and about the measurement statistics. In this paper, we describe two extensions to the parametric approach. First, we consider the problem of reconstruction from a pair of bi-plane angiograms that are acquired at different projection angles. Since bi-plane angiography systems are widely available, this is a practical measurement geometry. The patient may move between acquisitions, so we have extended our model to allow for object translation between the first and second pair of projections. Second, we describe how to accurately estimate the dimensions of a aneurysm from the dual-biplane angiogram. We applied the new algorithm to four synthetic angiograms (projection angles 0°, 20°, 90°, and 110°) of a vessel with a small aneurysm and an eccentric stenosis. The angiograms were corrupted by additive noise and background structure. Except near the top and bottom of the aneurysm, the estimated cross sections of the aneurysm and stenosis agree very well with the true cross sections.

Device for producing a fluid stream of varying composition

DOEpatents

Moss, Owen R.; Clark, Mark L.; Rossignol, E. John

1982-01-01

A device for producing a fluid stream of varying composition comprises a chamber having an inlet at one end and outlet at the other. Between the inlet and outlet there are substantially planar pans or baffles positioned normal to the bulk flow of fluid between the inlet and the outlet. These pans are arranged in pairs. Each pan, except those of the pair most remote from the inlet, is spaced from the walls of the chamber to permit air to flow past it. The pans of each pair are also spaced from each other, in a direction parallel to their planes, leaving an empty space along the mid-plane of the chamber. This produces a circulation and mixing of fluid between the pairs of pans or baffles. A secondary stream of fluid is introduced between two pairs of baffles in the intermediate portion of the chamber, so that the composition of the fluid is different in the portion adjacent to the outlet and the portion adjacent to the inlet. In a specific embodiment, the device is an exposure chamber for experimental animals, and the pans or baffles are catch pans for excrement.

THE AUSTRALIA TELESCOPE COMPACT ARRAY H I SURVEY OF THE GALACTIC CENTER

DOE Office of Scientific and Technical Information (OSTI.GOV)

McClure-Griffiths, N. M.; Green, J. A.; Dickey, J. M.

2012-03-01

We present a survey of atomic hydrogen (H I) emission in the direction of the Galactic Center (GC) conducted with the CSIRO Australia Telescope Compact Array (ATCA). The survey covers the area -5 Degree-Sign {<=} l {<=} +5 Degree-Sign , -5 Degree-Sign {<=} b {<=} +5 Degree-Sign over the velocity range -309 km s{sup -1} {<=} v{sub LSR} {<=} 349 km s{sup -1} with a velocity resolution of 1 km s{sup -1}. The ATCA data are supplemented with data from the Parkes Radio Telescope for sensitivity to all angular scales larger than the 145'' angular resolution of the survey. Themore » mean rms brightness temperature across the field is 0.7 K, except near (l, b) = 0 Degree-Sign , 0 Degree-Sign where it increases to {approx}2 K. This survey complements the Southern Galactic Plane Survey to complete the continuous coverage of the inner Galactic plane in H I at {approx}2' resolution. Here, we describe the observations and analysis of this GC survey and present the final data product. Features such as Bania's Clump 2, the far 3 kpc arm, and small high-velocity clumps are briefly described.« less

Free vibration of functionally graded carbon-nanotube-reinforced composite plates with cutout

PubMed Central

Mirzaei, Mostafa

2016-01-01

Summary During the past five years, it has been shown that carbon nanotubes act as an exceptional reinforcement for composites. For this reason, a large number of investigations have been devoted to analysis of fundamental, structural behavior of solid structures made of carbon-nanotube-reinforced composites (CNTRC). The present research, as an extension of the available works on the vibration analysis of CNTRC structures, examines the free vibration characteristics of plates containing a cutout that are reinforced with uniform or nonuniform distribution of carbon nanotubes. The first-order shear deformation plate theory is used to estimate the kinematics of the plate. The solution method is based on the Ritz method with Chebyshev basis polynomials. Such a solution method is suitable for arbitrary in-plane and out-of-plane boundary conditions of the plate. It is shown that through a functionally graded distribution of carbon nanotubes across the thickness of the plate, the fundamental frequency of a rectangular plate with or without a cutout may be enhanced. Furthermore, the frequencies are highly dependent on the volume fraction of carbon nanotubes and may be increased upon using more carbon nanotubes as reinforcement. PMID:27335742

Torsional Tribological Behavior and Torsional Friction Model of Polytetrafluoroethylene against 1045 Steel

PubMed Central

Wang, Shibo; Niu, Chengchao

2016-01-01

In this work, the plane-on-plane torsional fretting tribological behavior of polytetrafluoroethylene (PTFE) was studied. A model of a rigid, flat-ended punch acting on an elastic half-space was built according to the experimental conditions. The results indicate that the shape of T–θ curves was influenced by both the torsional angle and the normal load. The torsion friction torque and wear rate of PTFE exponentially decreased when the torsion angle rose. The torsional torque increased from 0.025 N·m under a normal load of 43 N to 0.082 N·m under a normal load of 123 N. With sequentially increasing normal load, the value of torque was maintained. With rising normal load, the wear mass loss of PTFE disks was increased and the wear rate was decreased. Good agreement was found with the calculated torque according to the model and the experimental torque except for that under a normal load of 163 N. The difference under a normal load of 163 N was caused by the coefficient of friction. Usually the coefficient of friction of a polymer decreases with increasing normal load, whereas a constant coefficient of friction was applied in the model. PMID:26799324

Determination of the resolution of a digital system for panoramic radiography based on CCD technology.

PubMed

Mastoris, Mihalis; Li, Gang; Welander, Ulf; McDavid, W D

2004-03-01

To determine Line Spread Functions (LSFs) and Modulation Transfer Functions (MTFs) for a digital system for panoramic radiography: the Dimax I (Planmeca Oy, Helsinki, Finland) based on Charge-Coupled Device (CCD) technology. A test object was specially designed having a gold foil positioned vertically. Images of the gold foil created edge functions that were used to determine LSFs and MTFs. The design of the test object made it possible to move the gold foil forward and backward relative to the central plane of the image layer by means of a micrometer screw. The experiment was carried out for different object depths in 5 different regions: the anterior, the canine, the premolar, the molar, and the TMJ regions. LSFs and MTFs were calculated using specially designed software. The results are presented graphically. LSFs and MTFs for the central plane were essentially the same for all regions. The MTFs for different object depths in the 5 investigated regions exhibited typical characteristics of MTFs for panoramic radiography with the exception for the functions for the molar region. The present findings indicate that the resolution of the Dimax I CCD system is comparable to that of film-based panoramic radiography.

Spatial organization of seismicity and fracture pattern at the boundary between Alps and Dinarides

NASA Astrophysics Data System (ADS)

Bressan, Gianni; Ponton, Maurizio; Rossi, Giuliana; Urban, Sandro

2016-04-01

The paper affords the study of the spatial organization of seismicity in the easternmost region of the Alps (Friuli, in NE Italy and W Slovenia), dominated by the interference between the Alpine and the Dinaric tectonic systems. Two non-conventional methods of spatial analysis are used: fractal analysis and principal component analysis (PCA). The fractal analysis helps to discriminate the cases in which hypocentres clearly define a plane, from the ones in which hypocenter distribution tends to the planarity, without reaching it. The PCA analysis is used to infer the orientation of planes fitting through earthquake foci, or the direction of propagation of the hypocentres. Furthermore, we study the spatial seismicity pattern at the shallow depths in the context of a general damage model, through the crack density distribution. The results of the three methods concur to a complex and composite model of fracturing in the region. The hypocentre pattern fills only partially a plane, i.e. has a fractal dimension close to 2. The three exceptions regard planes with Dinaric trend, without interference with Alpine lineaments. The shallowest depth range (0-10 km depth) is characterized by the activation of planes with variable orientations, reflecting the interference between the Dinaric and the Alpine tectonic structures, and closely bound to the variation of the mechanical properties of the crust. The seismicity occurs mostly in areas characterized by a variation from low to moderate crack density, indicating the sharp transition from zones of low damage to zones of moderate damage. Low crack density indicates the presence of more competent rocks capable of sustaining high strain energy while high crack density areas pertain to highly fractured rocks that cannot store high strain energy. Brittle failure, i.e. seismic activity, is favoured within the sharp transitions from low to moderate crack density zones. The orientation of the planes depicting the seismic activity, indeed, coincides with the orientation of the faults generated along the flanks of past carbonate platforms both in Friuli and western Slovenia. In the deepest depth range (10-20-km depth), on the contrary, the study evidences the dominance of the tectonic Dinaric system to the NW of the External Dinarides, in depth. This depth interval is characterized by a more organized pattern of seismicity. Seismic events mainly locate on the Dinaric lineaments in the northern and eastern parts of the region considered, while on Alpine thrusts in the western and southern parts.

Electronic structure and optical properties of boron nitride nanotube bundles from first principles

NASA Astrophysics Data System (ADS)

Behzad, Somayeh

2015-06-01

The electronic and optical properties of bundled armchair and zigzag boron nitride nanotubes (BNNTs) are investigated by using density functional theory. Owing to the inter-tube coupling, the dispersions along the tube axis and in the plane perpendicular to the tube axis of BNNT bundles are significantly varied, which are characterized by the decrease of band gap, the splitting of the doubly degenerated states, the expansions of valence and conduction bands. The calculated dielectric functions of the armchair and zigzag bundles are similar to that of the isolated tubes, except for the appearance of broadened peaks, small shifts of peak positions about 0.1 eV and increasing of peak intensities.

Effect of Processing Variables on Tensile Modulus and Morphology of Polyethylene/Clay Nanocomposites Prepared in an Internal Mixer

NASA Astrophysics Data System (ADS)

Ujianto, O.; Jollands, M.; Kao, N.

2018-03-01

A comparative study on effect of internal mixer on high density Polyethylene (HDPE)/clay nanocomposites preparation was done. Effect of temperature, rotor rotation (rpm), and mixing time, as well as rotor type (Roller and Banbury) on mechanical properties and morphology of HDPE/clay nanocomposites were studied using Box-Behnken experimental design. The model was developed according to secant modulus and confirmed to morphology analysis using Transmission Electron Microscopy (TEM). The finding suggests that there is different mechanisms occurred in each rotor to improve the mechanical properties. The mechanism in Roller is medium shear and medium diffusion, while Banbury is high shear and low diffusion. The difference in mechanism to disperse the clay particles attribute to the different optimum processing conditions in each rotor. The settings for roller samples are predicted around mid temperature, mid speed, and mid mixing time. There is no optimum setting for Banbury within the processing boundaries. The best settings for Banbury are at low, high, low settings. The morphology results showed a hybrid composite structure, with some exfoliations and some intercalations. There was a correlation between better mechanical properties and morphology with more exfoliation and thinner intercalated particles.

Mathematical Relationships between Neuron Morphology and Neurite Growth Dynamics in Drosophila melanogaster Larva Class IV Sensory Neurons

NASA Astrophysics Data System (ADS)

Ganguly, Sujoy; Liang, Xin; Grace, Michael; Lee, Daniel; Howard, Jonathon

The morphology of neurons is diverse and reflects the diversity of neuronal functions, yet the principles that govern neuronal morphogenesis are unclear. In an effort to better understand neuronal morphogenesis we will be focusing on the development of the dendrites of class IV sensory neuron in Drosophila melanogaster. In particular we attempt to determine how the the total length, and the number of branches of dendrites are mathematically related to the dynamics of neurite growth and branching. By imaging class IV neurons during early embryogenesis we are able to measure the change in neurite length l (t) as a function of time v (t) = dl / dt . We found that the distribution of v (t) is well characterized by a hyperbolic secant distribution, and that the addition of new branches per unit time is well described by a Poisson process. Combining these measurements with the assumption that branching occurs with equal probability anywhere along the dendrite we were able to construct a mathematical model that provides reasonable agreement with the observed number of branches, and total length of the dendrites of the class IV sensory neuron.

Fully coupled simulation of multiple hydraulic fractures to propagate simultaneously from a perforated horizontal wellbore

NASA Astrophysics Data System (ADS)

Zeng, Qinglei; Liu, Zhanli; Wang, Tao; Gao, Yue; Zhuang, Zhuo

2018-02-01

In hydraulic fracturing process in shale rock, multiple fractures perpendicular to a horizontal wellbore are usually driven to propagate simultaneously by the pumping operation. In this paper, a numerical method is developed for the propagation of multiple hydraulic fractures (HFs) by fully coupling the deformation and fracturing of solid formation, fluid flow in fractures, fluid partitioning through a horizontal wellbore and perforation entry loss effect. The extended finite element method (XFEM) is adopted to model arbitrary growth of the fractures. Newton's iteration is proposed to solve these fully coupled nonlinear equations, which is more efficient comparing to the widely adopted fixed-point iteration in the literatures and avoids the need to impose fluid pressure boundary condition when solving flow equations. A secant iterative method based on the stress intensity factor (SIF) is proposed to capture different propagation velocities of multiple fractures. The numerical results are compared with theoretical solutions in literatures to verify the accuracy of the method. The simultaneous propagation of multiple HFs is simulated by the newly proposed algorithm. The coupled influences of propagation regime, stress interaction, wellbore pressure loss and perforation entry loss on simultaneous propagation of multiple HFs are investigated.

Breathers and rogue waves in a Heisenberg ferromagnetic spin chain or an alpha helical protein

NASA Astrophysics Data System (ADS)

Yang, Jin-Wei; Gao, Yi-Tian; Su, Chuan-Qi; Wang, Qi-Min; Lan, Zhong-Zhou

2017-07-01

In this paper, a fourth-order variable-coefficient nonlinear Schrödinger equation for a one-dimensional continuum anisotropic Heisenberg ferromagnetic spin chain or an alpha helical protein has been investigated. Breathers and rogue waves are constructed via the Darboux transformation and generalized Darboux transformation, respectively. Results of the breathers and rogue waves are presented: (1) The first- and second-order Akhmediev breathers and Kuznetsov-Ma solitons are presented with different values of variable coefficients which are related to the energy transfer or higher-order excitations and interactions in the helical protein, or related to the spin excitations resulting from the lowest order continuum approximation and octupole-dipole interaction in a Heisenberg ferromagnetic spin chain, and the nonlinear periodic breathers resulting from the Akhmediev breathers are studied as well; (2) For the first- and second-order rogue waves, we find that they can be split into many similar components when the variable coefficients are polynomial functions of time; (3) Rogue waves can also be split when the variable coefficients are hyperbolic secant functions of time, but the profile of each component in such a case is different.

Evaluating the material parameters of the human cornea in a numerical model.

PubMed

Sródka, Wiesław

2011-01-01

The values of the biomechanical human eyeball model parameters reported in the literature are still being disputed. The primary motivation behind this work was to predict the material parameters of the cornea through numerical simulations and to assess the applicability of the ubiquitously accepted law of applanation tonometry - the Imbert-Fick equation. Numerical simulations of a few states of eyeball loading were run to determine the stroma material parameters. In the computations, the elasticity moduli of the material were related to the stress sign, instead of the orientation in space. Stroma elasticity secant modulus E was predicted to be close to 0.3 MPa. The numerically simulated applanation tonometer readings for the cornea with the calibration dimensions were found to be lower by 11 mmHg then IOP = 48 mmHg. This discrepancy is the result of a strictly mechanical phenomenon taking place in the tensioned and simultaneously flattened corneal shell and is not related to the tonometer measuring accuracy. The observed deviation has not been amenable to any GAT corrections, contradicting the Imbert-Fick law. This means a new approach to the calculation of corrections for GAT readings is needed.

Lateral Penumbra Modelling Based Leaf End Shape Optimization for Multileaf Collimator in Radiotherapy.

PubMed

Zhou, Dong; Zhang, Hui; Ye, Peiqing

2016-01-01

Lateral penumbra of multileaf collimator plays an important role in radiotherapy treatment planning. Growing evidence has revealed that, for a single-focused multileaf collimator, lateral penumbra width is leaf position dependent and largely attributed to the leaf end shape. In our study, an analytical method for leaf end induced lateral penumbra modelling is formulated using Tangent Secant Theory. Compared with Monte Carlo simulation and ray tracing algorithm, our model serves well the purpose of cost-efficient penumbra evaluation. Leaf ends represented in parametric forms of circular arc, elliptical arc, Bézier curve, and B-spline are implemented. With biobjective function of penumbra mean and variance introduced, genetic algorithm is carried out for approximating the Pareto frontier. Results show that for circular arc leaf end objective function is convex and convergence to optimal solution is guaranteed using gradient based iterative method. It is found that optimal leaf end in the shape of Bézier curve achieves minimal standard deviation, while using B-spline minimum of penumbra mean is obtained. For treatment modalities in clinical application, optimized leaf ends are in close agreement with actual shapes. Taken together, the method that we propose can provide insight into leaf end shape design of multileaf collimator.

Effect of stearic acid-grafted starch compatibilizer on properties of linear low density polyethylene/thermoplastic starch blown film.

PubMed

Khanoonkon, Nattaporn; Yoksan, Rangrong; Ogale, Amod A

2016-02-10

The present work aims to investigate the effect of stearic acid-grafted starch (ST-SA) on the rheological, thermal, optical, dynamic mechanical thermal, and tensile properties of linear low density polyethylene/thermoplastic starch (LLDPE/TPS) blends, as well as on their water vapor and oxygen barrier properties. Blends consisting of LLDPE and TPS in a weight ratio of 60:40 and ST-SA at different concentrations, i.e. 1, 3 and 5%, were prepared using a twin-screw extruder. The obtained resins were subsequently converted into films via blown film extrusion. Incorporation of ST-SA resulted in a decreased degree of shear thinning, reduced ambient temperature elasticity, and improved tensile strength, secant modulus, extensibility, and UV absorption, as well as diminished water vapor and oxygen permeabilities of the LLDPE/TPS blend. These effects are attributed to the enhanced interfacial adhesion between LLDPE and TPS phases through the compatibilizing effect induced by ST-SA, and the good dispersion of the TPS phase in the LLDPE matrix. The results confirmed that ST-SA could potentially be used as a compatibilizer for the LLDPE/TPS blend system. Copyright © 2015 Elsevier Ltd. All rights reserved.

An Evaluation of the Measurement Requirements for an In-Situ Wake Vortex Detection System

NASA Technical Reports Server (NTRS)

Fuhrmann, Henri D.; Stewart, Eric C.

1996-01-01

Results of a numerical simulation are presented to determine the feasibility of estimating the location and strength of a wake vortex from imperfect in-situ measurements. These estimates could be used to provide information to a pilot on how to avoid a hazardous wake vortex encounter. An iterative algorithm based on the method of secants was used to solve the four simultaneous equations describing the two-dimensional flow field around a pair of parallel counter-rotating vortices of equal and constant strength. The flow field information used by the algorithm could be derived from measurements from flow angle sensors mounted on the wing-tip of the detecting aircraft and an inertial navigation system. The study determined the propagated errors in the estimated location and strength of the vortex which resulted from random errors added to theoretically perfect measurements. The results are summarized in a series of charts and a table which make it possible to estimate these propagated errors for many practical situations. The situations include several generator-detector airplane combinations, different distances between the vortex and the detector airplane, as well as different levels of total measurement error.

A procedure for the reliability improvement of the oblique ionograms automatic scaling algorithm

NASA Astrophysics Data System (ADS)

Ippolito, Alessandro; Scotto, Carlo; Sabbagh, Dario; Sgrigna, Vittorio; Maher, Phillip

2016-05-01

A procedure made by the combined use of the Oblique Ionogram Automatic Scaling Algorithm (OIASA) and Autoscala program is presented. Using Martyn's equivalent path theorem, 384 oblique soundings from a high-quality data set have been converted into vertical ionograms and analyzed by Autoscala program. The ionograms pertain to the radio link between Curtin W.A. (CUR) and Alice Springs N.T. (MTE), Australia, geographical coordinates (17.60°S; 123.82°E) and (23.52°S; 133.68°E), respectively. The critical frequency foF2 values extracted from the converted vertical ionograms by Autoscala were then compared with the foF2 values derived from the maximum usable frequencies (MUFs) provided by OIASA. A quality factor Q for the MUF values autoscaled by OIASA has been identified. Q represents the difference between the foF2 value scaled by Autoscala from the converted vertical ionogram and the foF2 value obtained applying the secant law to the MUF provided by OIASA. Using the receiver operating characteristic curve, an appropriate threshold level Qt was chosen for Q to improve the performance of OIASA.

A comparative study of breast cancer diagnosis based on neural network ensemble via improved training algorithms.

PubMed

Azami, Hamed; Escudero, Javier

2015-08-01

Breast cancer is one of the most common types of cancer in women all over the world. Early diagnosis of this kind of cancer can significantly increase the chances of long-term survival. Since diagnosis of breast cancer is a complex problem, neural network (NN) approaches have been used as a promising solution. Considering the low speed of the back-propagation (BP) algorithm to train a feed-forward NN, we consider a number of improved NN trainings for the Wisconsin breast cancer dataset: BP with momentum, BP with adaptive learning rate, BP with adaptive learning rate and momentum, Polak-Ribikre conjugate gradient algorithm (CGA), Fletcher-Reeves CGA, Powell-Beale CGA, scaled CGA, resilient BP (RBP), one-step secant and quasi-Newton methods. An NN ensemble, which is a learning paradigm to combine a number of NN outputs, is used to improve the accuracy of the classification task. Results demonstrate that NN ensemble-based classification methods have better performance than NN-based algorithms. The highest overall average accuracy is 97.68% obtained by NN ensemble trained by RBP for 50%-50% training-test evaluation method.

Identification of victims of the 1998 Taoyuan Airbus crash accident using DNA analysis.

PubMed

Hsu, C M; Huang, N E; Tsai, L C; Kao, L G; Chao, C H; Linacre, A; Lee, J C

1999-01-01

In February 1998 a civilian aeroplane carrying 196 individuals crashed in Taiwan and killed another 6 people on the ground. Although there were dental and medical records, fingerprints, photographic evidence and personal effects to identify some of the victims, DNA analysis was required to further identify severely damaged remains. From the 202 people known to have perished in the plane crash, a total of 685 fragments of human remains were subjected to DNA analysis. The analysis was carried out using nine microsatellite loci, plus amelogenin to cluster the 685 fragments into 202 groups, accounting for all the victims. To establish genetic relatedness of the victims to other victims and living relatives, additional DNA loci were used. In this case the paternity index was increased by using HLA DQA1 plus Polymarker. The same 16 DNA loci were used to test blood samples from 201 relatives to establish parent/child and sibling relationships. With the exception of 19 victims identified by non-genetic evidence, 183 victims were successfully identified by DNA typing with relatively high values of paternity index by the direct or indirect comparison of relatives. The 202 victims were from 37 different families, ranging in size from 2 to 13 members and 74 individuals known to be unrelated to any other victim. The DNA from living relatives was used to identify one member of a family group, from which other victims of the family could be identified. ABO blood group information was further used to confirm genetic relatedness within families. A comparison of the DNA profiling results to the ABO blood group of the victims showed no discrepancies with the exception of two mutations in the FGA locus. In cases of severely damaged victims from a plane crash, DNA analysis proved to be the best choice to identify victims.

Interplanetary fast shocks and associated drivers observed through the 23rd solar minimum by Wind over its first 2.5 years

NASA Astrophysics Data System (ADS)

Berdichevsky, Daniel B.; Szabo, Adam; Lepping, Ronald P.; Viñas, Adolfo F.; Mariani, Franco

2000-12-01

A list of the interplanetary shocks observed by Wind from its launch (in Nov 1994) to May 1997 is presented. The magnetohydrodynamic nature of the shocks is investigated, and the associated shock parameters and their uncertainties are accurately computed using two techniques. These are: 1) a combination of the ``preaveraged'' magnetic-coplanarity, velocity-coplanarity, and the Abraham-Schrauner-mixed methods, and 2) the Viñas and Scudder [1986] technique for solving the nonlinear least squares Rankine-Hugoniot equations. Within acceptable limits these two techniques generally gave the same results, with some exceptions. The reasons for the exceptions are discussed. The mean strength and rate of occurrence of the shocks appear to correlate with the solar cycle. Both showed a decrease in 1996 coincident with the time of the lowest ultraviolet solar radiance, indicative of solar minimum and the beginning of solar cycle 23. Eighteen shocks appeared to be associated with corotating interaction regions (CIRs). The shock normal distribution showed a mean direction peaking in the ecliptic plane and with a longitude of ~200° (GSE coordinates). Another 16 shocks were determined to be driven by solar transients, including magnetic clouds. These had a broader distribution of normal directions than those of the CIR cases with a mean direction close to the Sun-Earth line. Eight shocks of unknown origin had normal orientations far off the ecliptic plane. No shock propagated with longitude φn>=220+/-10°, i.e. against the average Parker spiral direction. Examination of the obliquity angle θBn (i.e., between the shock normal and the upstream interplanetary magnetic field) for the full set of shocks revealed that about 58% were quasi-perpendicular, and about 32% of the shocks oblique, and the rest quasi-parallel. Small uncertainty in the estimated angle θBn was obtained for about 10 shocks with magnetosonic Mach numbers between 1 and 2.

The effect of morphine added to bupivacaine in ultrasound guided transversus abdominis plane (TAP) block for postoperative analgesia following lower abdominal cancer surgery, a randomized controlled study.

PubMed

El Sherif, Fatma Adel; Mohamed, Sahar Abdel-Baky; Kamal, Shereen Mamdouh

2017-06-01

Transversus abdominis plane (TAP) block used for management of surgical abdominal pain by injecting local anesthetics into the plane between the internal oblique and transversus abdominis muscles. We aimed to explore the effect of adding morphine to bupivacaine in ultrasound guided TAP-block in patients undergoing lower abdominal cancer surgery. Randomized, double-blind, prospective study. Clinical trial identifier: NCT02566096. Academic medical center. Sixty patients were enrolled in this study after ethical committee approval. Patients divided into 2 groups (30 each): Bupivacaine group (GB): given ultrasound guided TAP-block 20ml 0.5% bupivacaine diluted in 20ml saline; Morphine group (GM): given ultrasound guided TAP-block with 20ml 0.5% bupivacaine+10mg morphine sulphate diluted in 20ml saline. Patients were observed for total morphine consumption, time for first request of rescue analgesia, sedation scores, hemodynamics and side effects for 24h postoperatively. Morphine added to bupivacaine in TAP block compared to bupivacaine alone reduced total morphine consumption (5.33±1.28mg) (10.70±3.09mg) respectively (p<0.001), prolonged the time to first request of analgesia (10.40±4.96h) (6.97±3.26h) respectively (p<0.008), with a statistically significant decrease in (VAS-M) in GM compared with GB at 12h postoperatively (p<0.002). No significant differences in hemodynamics, respiratory rate, oxygen saturation, sedation score, and side effects except for nausea were observed (p>0.05). Addition of morphine to bupivacaine in TAP block is effective method for pain management in patients undergoing major abdominal cancer surgery without serious side effects. Copyright © 2017 Elsevier Inc. All rights reserved.

Two charges on plane in a magnetic field I. “Quasi-equal” charges and neutral quantum system at rest cases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Escobar-Ruiz, M.A., E-mail: mauricio.escobar@nucleares.unam.mx; Turbiner, A.V., E-mail: turbiner@nucleares.unam.mx

Low-lying bound states for the problem of two Coulomb charges of finite masses on a plane subject to a constant magnetic field B perpendicular to the plane are considered. Major emphasis is given to two systems: two charges with the equal charge-to-mass ratio (quasi-equal charges) and neutral systems with concrete results for the hydrogen atom and two electrons (quantum dot). It is shown that for these two cases, when a neutral system is at rest (the center-of-mass momentum is zero), some outstanding properties occur: in double polar coordinates in CMS (R,ϕ) and relative (ρ,φ) coordinate systems (i) the eigenfunctions aremore » factorizable, all factors except for ρ-dependent are found analytically, they have definite relative angular momentum, (ii) dynamics in ρ-direction is the same for both systems being described by a funnel-type potential; (iii) at some discrete values of dimensionless magnetic fields b≤1 the system becomes quasi-exactly-solvable and a finite number of eigenfunctions in ρ are polynomials. The variational method is employed. Trial functions are based on combining for the phase of a wavefunction (a) the WKB expansion at large distances, (b) the perturbation theory at small distances (c) with a form of the known analytically (quasi-exactly-solvable) eigenfunctions. Such a form of trial function appears as a compact uniform approximation for lowest eigenfunctions. For the lowest states with relative magnetic quantum numbers s=0,1,2 this approximation gives not less than 7 s.d., 8 s.d., 9 s.d., respectively, for the total energy E(B) for magnetic fields 0.049a.u.« less

Determination of the Fracture Parameters in a Stiffened Composite Panel

NASA Technical Reports Server (NTRS)

Lin, Chung-Yi

2000-01-01

A modified J-integral, namely the equivalent domain integral, is derived for a three-dimensional anisotropic cracked solid to evaluate the stress intensity factor along the crack front using the finite element method. Based on the equivalent domain integral method with auxiliary fields, an interaction integral is also derived to extract the second fracture parameter, the T-stress, from the finite element results. The auxiliary fields are the two-dimensional plane strain solutions of monoclinic materials with the plane of symmetry at x(sub 3) = 0 under point loads applied at the crack tip. These solutions are expressed in a compact form based on the Stroh formalism. Both integrals can be implemented into a single numerical procedure to determine the distributions of stress intensity factor and T-stress components, T11, T13, and thus T33, along a three-dimensional crack front. The effects of plate thickness and crack length on the variation of the stress intensity factor and T-stresses through the thickness are investigated in detail for through-thickness center-cracked plates (isotropic and orthotropic) and orthotropic stiffened panels under pure mode-I loading conditions. For all the cases studied, T11 remains negative. For plates with the same dimensions, a larger size of crack yields larger magnitude of the normalized stress intensity factor and normalized T-stresses. The results in orthotropic stiffened panels exhibit an opposite trend in general. As expected, for the thicker panels, the fracture parameters evaluated through the thickness, except the region near the free surfaces, approach two-dimensional plane strain solutions. In summary, the numerical methods presented in this research demonstrate their high computational effectiveness and good numerical accuracy in extracting these fracture parameters from the finite element results in three-dimensional cracked solids.

Transversus Abdominis Plane Block Versus Surgical Site Infiltration for Pain Management After Open Total Abdominal Hysterectomy.

PubMed

Gasanova, Irina; Alexander, John; Ogunnaike, Babatunde; Hamid, Cherine; Rogers, David; Minhajuddin, Abu; Joshi, Girish P

2015-11-01

Surgical site infiltration and transversus abdominis plane (TAP) blocks are commonly used to improve pain relief after lower abdominal surgery. This randomized, observer-blinded study was designed to compare the analgesic efficacy of TAP blocks with surgical site infiltration in patients undergoing open total abdominal hysterectomy via a Pfannenstiel incision. Patients were randomized to receive either bilateral ultrasound-guided TAP blocks using bupivacaine 0.5% 20 mL on each side (n = 30) or surgical site infiltration with liposomal bupivacaine 266 mg diluted to 60 mL injected in the preperitoneal, subfascial, and subcutaneous planes (n = 30). The remaining aspects of the perioperative care were standardized. An investigator blinded to the group allocation documented pain scores at rest and with coughing, opioid requirements, nausea, vomiting, and rescue antiemetics in the postanesthesia care unit and at 2, 6, 12, 24, and 48 hours postoperatively. The primary outcome measure was pain scores on coughing at 6 hours postoperatively. One patient in each group was excluded from the analysis because of reoperation within 24 hours in the TAP block group and change of incision type in the infiltration group. The pain scores at rest and with coughing were significantly lower in the surgical site infiltration group at all postoperative time points (P < 0.0001) except at rest in the postanesthesia care unit. The opioid requirements between 24 and 48 hours were significantly lower in the infiltration group (P = 0.009). The nausea scores, occurrence of vomiting, and need for rescue antiemetics were similar. Surgical site infiltration provided superior pain relief at rest and on coughing, as well as reduced opioid consumption for up to 48 hours. Future studies need to compare TAP blocks with liposomal bupivacaine with surgical site infiltration with liposomal bupivacaine.

Directional constraint of endpoint force emerges from hindlimb anatomy.

PubMed

Bunderson, Nathan E; McKay, J Lucas; Ting, Lena H; Burkholder, Thomas J

2010-06-15

Postural control requires the coordination of force production at the limb endpoints to apply an appropriate force to the body. Subjected to horizontal plane perturbations, quadruped limbs stereotypically produce force constrained along a line that passes near the center of mass. This phenomenon, referred to as the force constraint strategy, may reflect mechanical constraints on the limb or body, a specific neural control strategy or an interaction among neural controls and mechanical constraints. We used a neuromuscular model of the cat hindlimb to test the hypothesis that the anatomical constraints restrict the mechanical action of individual muscles during stance and constrain the response to perturbations to a line independent of perturbation direction. In a linearized neuromuscular model of the cat hindlimb, muscle lengthening directions were highly conserved across 10,000 different muscle activation patterns, each of which produced an identical, stance-like endpoint force. These lengthening directions were closely aligned with the sagittal plane and reveal an anatomical structure for directionally constrained force responses. Each of the 10,000 activation patterns was predicted to produce stable stance based on Lyapunov stability analysis. In forward simulations of the nonlinear, seven degree of freedom model under the action of 200 random muscle activation patterns, displacement of the endpoint from its equilibrium position produced restoring forces, which were also biased toward the sagittal plane. The single exception was an activation pattern based on minimum muscle stress optimization, which produced destabilizing force responses in some perturbation directions. The sagittal force constraint increased during simulations as the system shifted from an inertial response during the acceleration phase to a viscoelastic response as peak velocity was obtained. These results qualitatively match similar experimental observations and suggest that the force constraint phenomenon may result from the anatomical arrangement of the limb.

Directional constraint of endpoint force emerges from hindlimb anatomy

PubMed Central

Bunderson, Nathan E.; McKay, J. Lucas; Ting, Lena H.; Burkholder, Thomas J.

2010-01-01

Postural control requires the coordination of force production at the limb endpoints to apply an appropriate force to the body. Subjected to horizontal plane perturbations, quadruped limbs stereotypically produce force constrained along a line that passes near the center of mass. This phenomenon, referred to as the force constraint strategy, may reflect mechanical constraints on the limb or body, a specific neural control strategy or an interaction among neural controls and mechanical constraints. We used a neuromuscular model of the cat hindlimb to test the hypothesis that the anatomical constraints restrict the mechanical action of individual muscles during stance and constrain the response to perturbations to a line independent of perturbation direction. In a linearized neuromuscular model of the cat hindlimb, muscle lengthening directions were highly conserved across 10,000 different muscle activation patterns, each of which produced an identical, stance-like endpoint force. These lengthening directions were closely aligned with the sagittal plane and reveal an anatomical structure for directionally constrained force responses. Each of the 10,000 activation patterns was predicted to produce stable stance based on Lyapunov stability analysis. In forward simulations of the nonlinear, seven degree of freedom model under the action of 200 random muscle activation patterns, displacement of the endpoint from its equilibrium position produced restoring forces, which were also biased toward the sagittal plane. The single exception was an activation pattern based on minimum muscle stress optimization, which produced destabilizing force responses in some perturbation directions. The sagittal force constraint increased during simulations as the system shifted from an inertial response during the acceleration phase to a viscoelastic response as peak velocity was obtained. These results qualitatively match similar experimental observations and suggest that the force constraint phenomenon may result from the anatomical arrangement of the limb. PMID:20511528

Correlation of Beta Angle with Antero-Posterior Dysplasia Indicators and FMA: An Institution Based Cephalometric Study.

PubMed

Singh, Gurinder; Verma, Sanjeev; Singh, Devinder Preet; Yadav, Sumit Kumar; Yadav, Achla Bharti

2016-11-01

Beta angle utilizes three skeletal landmarks - point A, point B, and point C (the apparent axis of the condyle). It is formed between A-B line and point A perpendicular to C-B line. Further this angle indicates the severity and the type of skeletal dysplasia in the sagittal dimension and it changes with the growth pattern of the patient. Hence, it is important to study the dependence of beta angle on the growth pattern. The present study was designed to evaluate the correlation of Beta angle with point A-Nasion-point B (ANB) angle, points A and B to palatal plane (App-Bpp), Wit's appraisal and Maxillary-Mandibular plane angle Bisector (MMB) and Frankfort-Mandibular plane Angle (FMA) in Skeletal Class I, Class II and Class III malocclusion groups. Pre-treatment lateral head cephalo-grams of 120 subjects in age group of 15-25 years were obtained. Three skeletal Class I, Class II and Class III malocclusion groups (40 each) were assorted on the basis of ANB, MMB, App-Bpp, Wit's appraisal and FMA. Analysis of variance (ANOVA) and mean differences were calculated to compare the study groups. Bivariate correlations among different parameters of these groups were obtained. Normal values of beta angle in skeletal Class I group, skeletal Class II group and skeletal Class III group was 31.33±3.25, 25.28±4.28 and 40.93±4.55 respectively. Overall beta angle showed a strong correlation with all parameters of anterio-posterior dysplasia indicators except FMA. Beta angle shows weak correlation with FMA and is not affected by growth pattern/jaw rotation. The normal values are in same range irrespective of the differences in craniofacial morphology.

Correlation of Beta Angle with Antero-Posterior Dysplasia Indicators and FMA: An Institution Based Cephalometric Study

PubMed Central

Singh, Gurinder; Verma, Sanjeev; Singh, Devinder Preet; Yadav, Achla Bharti

2016-01-01

Introduction Beta angle utilizes three skeletal landmarks – point A, point B, and point C (the apparent axis of the condyle). It is formed between A-B line and point A perpendicular to C-B line. Further this angle indicates the severity and the type of skeletal dysplasia in the sagittal dimension and it changes with the growth pattern of the patient. Hence, it is important to study the dependence of beta angle on the growth pattern. Aim The present study was designed to evaluate the correlation of Beta angle with point A–Nasion–point B (ANB) angle, points A and B to palatal plane (App-Bpp), Wit’s appraisal and Maxillary-Mandibular plane angle Bisector (MMB) and Frankfort-Mandibular plane Angle (FMA) in Skeletal Class I, Class II and Class III malocclusion groups. Materials and Methods Pre-treatment lateral head cephalo-grams of 120 subjects in age group of 15-25 years were obtained. Three skeletal Class I, Class II and Class III malocclusion groups (40 each) were assorted on the basis of ANB, MMB, App-Bpp, Wit’s appraisal and FMA. Analysis of variance (ANOVA) and mean differences were calculated to compare the study groups. Bivariate correlations among different parameters of these groups were obtained. Results Normal values of beta angle in skeletal Class I group, skeletal Class II group and skeletal Class III group was 31.33±3.25, 25.28±4.28 and 40.93±4.55 respectively. Overall beta angle showed a strong correlation with all parameters of anterio-posterior dysplasia indicators except FMA. Conclusion Beta angle shows weak correlation with FMA and is not affected by growth pattern/jaw rotation. The normal values are in same range irrespective of the differences in craniofacial morphology. PMID:28050509

Simultaneous metal-insulator and antiferromagnetic transitions in orthorhombic perovskite iridate S r0.94I r0.78O2.68 single crystals

NASA Astrophysics Data System (ADS)

Zheng, H.; Terzic, J.; Ye, Feng; Wan, X. G.; Wang, D.; Wang, Jinchen; Wang, Xiaoping; Schlottmann, P.; Yuan, S. J.; Cao, G.

2016-06-01

The orthorhombic perovskite SrIr O3 is a semimetal, an intriguing exception in iridates where the strong spin-orbit interaction coupled with electron correlations tends to impose an insulating state. We report results of our investigation of bulk single-crystal S r0.94I r0.78O2.68 or Ir-deficient, orthorhombic perovskite SrIr O3 . It retains the same crystal structure as stoichiometric SrIr O3 but exhibits a sharp, simultaneous antiferromagnetic (AFM) and metal-insulator (MI) transition occurring in the basal-plane resistivity at 185 K. Above it, the basal-plane resistivity features an extended regime of almost linear temperature dependence up to 800 K but the strong electronic anisotropy renders an insulating behavior in the out-of-plane resistivity. The Hall resistivity undergoes an abrupt sign change and grows below 40 K, which along with the Sommerfeld constant of 20 mJ /mol K2 suggests a multiband effect. All results including our first-principles calculations underscore a delicacy of the paramagnetic, metallic state in SrIr O3 that is in close proximity to an AFM insulating state. The contrasting ground states in isostructural S r0.94I r0.78O2.68 and SrIr O3 illustrate a critical role of lattice distortions and Ir deficiency in rebalancing the ground state in the iridates. Finally, the concurrent AFM and MI transitions reveal a direct correlation between the magnetic transition and formation of an activation gap in the iridate, which is conspicuously absent in S r2Ir O4 .

Infrared Spectroscopy of Polycyclic Aromatic Hydrocarbon Cations. 3; The Members

NASA Technical Reports Server (NTRS)

Hudgins, D. M.; Allamandola, L. J.; Wittebon, Fred C. (Technical Monitor)

1994-01-01

In spite of the fact that the infrared spectroscopic properties of only a few isolated ionized polycyclic aromatic hydrocarbons (PAHs) are known, gaseous, ionized PAHs are thought to be responsible for a very common family of infrared interstellar emission bands. In order to provide a data base to test this hypothesis and, if borne out, to use this emission band family as a probe of many different interstellar environments, we are carrying out a thorough study of the infrared spectroscopic properties of neutral and ionized PAHs in argon matrices. Here we present the near and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene: phenanthrene, pyrene, benzo[e]pyrene, benzo[ghilperylene, and coronene. The properties of naphthalene, the first member of the series, are given elsewhere. The spectra of perdeuterated phenanthrene and pyrene are also reported. For those molecules which have been previously studied (pyrene, d(10)-pyrene, and coronene), band positions and relative intensities are in agreement. In all cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeutero-phenanthrene, pyrene, benzo[ghi]perylene, and coronene cations. With the exception of coronene,the cation bands corresponding to the CC modes are typically 2-5 times more intense than those of the CH out-of-plane bending vibrations. For the cations the CC stretching and CH in-plane bending modes give rise to bands which are an order of magnitude stronger than for the neutral species, and the CH out-of-plane bends produce bands which are 5-20 times weaker than in the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.

Temporomandibular Disorders: The Habitual Chewing Side Syndrome

PubMed Central

Santana-Mora, Urbano; López-Cedrún, José; Mora, María J.; Otero, Xosé L.; Santana-Penín, Urbano

2013-01-01

Background Temporomandibular disorders are the most common cause of chronic orofacial pain, but, except where they occur subsequent to trauma, their cause remains unknown. This cross-sectional study assessed chewing function (habitual chewing side) and the differences of the chewing side and condylar path and lateral anterior guidance angles in participants with chronic unilateral temporomandibular disorder. This is the preliminary report of a randomized trial that aimed to test the effect of a new occlusal adjustment therapy. Methods The masticatory function of 21 randomly selected completely dentate participants with chronic temporomandibular disorders (all but one with unilateral symptoms) was assessed by observing them eat almonds, inspecting the lateral horizontal movement of the jaw, with kinesiography, and by means of interview. The condylar path in the sagittal plane and the lateral anterior guidance angles with respect to the Frankfort horizontal plane in the frontal plane were measured on both sides in each individual. Results Sixteen of 20 participants with unilateral symptoms chewed on the affected side; the concordance (Fisher’s exact test, P = .003) and the concordance-symmetry level (Kappa coefficient κ = 0.689; 95% confidence interval [CI], 0.38 to 0.99; P = .002) were significant. The mean condylar path angle was steeper (53.47(10.88) degrees versus 46.16(7.25) degrees; P = .001), and the mean lateral anterior guidance angle was flatter (41.63(13.35) degrees versus 48.32(9.53) degrees P = .036) on the symptomatic side. Discussion The results of this study support the use of a new term based on etiology, “habitual chewing side syndrome”, instead of the nonspecific symptom-based “temporomandibular joint disorders”; this denomination is characterized in adults by a steeper condylar path, flatter lateral anterior guidance, and habitual chewing on the symptomatic side. PMID:23593156

The 2011 Mw 7.1 Van (Eastern Turkey) earthquake

USGS Publications Warehouse

Elliot, John R.; Copley, Alex C.; Holley, R.; Scharer, Katherine M.; Parsons, Barry

2013-01-01

We use interferometric synthetic aperture radar (InSAR), body wave seismology, satellite imagery, and field observations to constrain the fault parameters of the Mw 7.1 2011 Van (Eastern Turkey) reverse-slip earthquake, in the Turkish-Iranian plateau. Distributed slip models from elastic dislocation modeling of the InSAR surface displacements from ENVISAT and COSMO-SkyMed interferograms indicate up to 9 m of reverse and oblique slip on a pair of en echelon NW 40 °–54 ° dipping fault planes which have surface extensions projecting to just 10 km north of the city of Van. The slip remained buried and is relatively deep, with a centroid depth of 14 km, and the rupture reaching only within 8–9 km of the surface, consistent with the lack of significant ground rupture. The up-dip extension of this modeled WSW striking fault plane coincides with field observations of weak ground deformation seen on the western of the two fault segments and has a dip consistent with that seen at the surface in fault gouge exposed in Quaternary sediments. No significant coseismic slip is found in the upper 8 km of the crust above the main slip patches, except for a small region on the eastern segment potentially resulting from the Mw 5.9 aftershock on the same day. We perform extensive resolution tests on the data to confirm the robustness of the observed slip deficit in the shallow crust. We resolve a steep gradient in displacement at the point where the planes of the two fault segments ends are inferred to abut at depth, possibly exerting some structural control on rupture extent.

Neuroanatomy of the killer whale (Orcinus orca) from magnetic resonance images.

PubMed

Marino, Lori; Sherwood, Chet C; Delman, Bradley N; Tang, Cheuk Y; Naidich, Thomas P; Hof, Patrick R

2004-12-01

This article presents the first series of MRI-based anatomically labeled sectioned images of the brain of the killer whale (Orcinus orca). Magnetic resonance images of the brain of an adult killer whale were acquired in the coronal and axial planes. The gross morphology of the killer whale brain is comparable in some respects to that of other odontocete brains, including the unusual spatial arrangement of midbrain structures. There are also intriguing differences. Cerebral hemispheres appear extremely convoluted and, in contrast to smaller cetacean species, the killer whale brain possesses an exceptional degree of cortical elaboration in the insular cortex, temporal operculum, and the cortical limbic lobe. The functional and evolutionary implications of these features are discussed. (c) 2004 Wiley-Liss, Inc.

Mg II chromospheric-emission dating of HR 1614 moving-group stars

NASA Technical Reports Server (NTRS)

Hufnagel, Beth; Smith, Graeme H.

1994-01-01

A 2800 A Mg II line index I(Mg II) that is sensitive to chromospheric activity has been measured from International Ultraviolet Explorer spectra of a sample of eight HR 1614 moving-group dwarfs. All of these dwarfs have values of I(Mg II) indicative of ages greater than or equal to 3 Gyr. The relatively old ages of these dwarfs, together with their similar and peculiar kinematics and high metal abundance, is consistent with, although not conclusive proof of, coeval formation in close physical proximity to each other. The age, chemical abundance, and kinematics of the HR 1614 moving group -- with the notable exception of height above the Galactic plane -- are similar to the properties of the old open cluster NGC 6791.

Crystal structure of ethyl (E)-2-cyano-3-(thio-phen-2-yl)acrylate: two conformers forming a discrete disorder.

PubMed

Castro Agudelo, Brian; Cárdenas, Juan C; Macías, Mario A; Ochoa-Puentes, Cristian; Sierra, Cesar A

2017-09-01

In the title compound, C 10 H 9 NO 2 S, all the non-H atoms, except for the ethyl fragment, lie nearly in the same plane. Despite the mol-ecular planarity, the ethyl fragment presents more than one conformation, giving rise to a discrete disorder, which was modelled with two different crystallographic sites for the eth-oxy O and eth-oxy α-C atoms, with occupancy values of 0.5. In the crystal, the three-dimensional array is mainly directed by C-H⋯(O,N) inter-actions, giving rise to inversion dimers with R 2 2 (10) and R 2 2 (14) motifs and infinite chains running along the [100] direction.

Stacked graphene nanofibers for electrochemical oxidation of DNA bases.

PubMed

Ambrosi, Adriano; Pumera, Martin

2010-08-21

In this article, we show that stacked graphene nanofibers (SGNFs) demonstrate superior electrochemical performance for oxidation of DNA bases over carbon nanotubes (CNTs). This is due to an exceptionally high number of accessible graphene sheet edges on the surface of the nanofibers when compared to carbon nanotubes, as shown by transmission electron microscopy and Raman spectroscopy. The oxidation signals of adenine, guanine, cytosine, and thymine exhibit two to four times higher currents than on CNT-based electrodes. SGNFs also exhibit higher sensitivity than do edge-plane pyrolytic graphite, glassy carbon, or graphite microparticle-based electrodes. We also demonstrate that influenza A(H1N1)-related strands can be sensitively oxidized on SGNF-based electrodes, which could therefore be applied to label-free DNA analysis.

Stabilized high-accuracy correction of ocular aberrations with liquid crystal on silicon spatial light modulator in adaptive optics retinal imaging system.

PubMed

Huang, Hongxin; Inoue, Takashi; Tanaka, Hiroshi

2011-08-01

We studied the long-term optical performance of an adaptive optics scanning laser ophthalmoscope that uses a liquid crystal on silicon spatial light modulator to correct ocular aberrations. The system achieved good compensation of aberrations while acquiring images of fine retinal structures, excepting during sudden eye movements. The residual wavefront aberrations collected over several minutes in several situations were statistically analyzed. The mean values of the root-mean-square residual wavefront errors were 23-30 nm, and for around 91-94% of the effective time the errors were below the Marechal criterion for diffraction limited imaging. The ability to axially shift the imaging plane to different retinal depths was also demonstrated.

Subsonic static and dynamic stability characteristics of the test technique demonstrator NASP configuration

NASA Technical Reports Server (NTRS)

Boyden, Richmond P.; Dress, David A.; Fox, Charles H., Jr.; Huffman, Jarrett K.; Cruz, Christopher I.

1993-01-01

The paper describes the procedure used for and the results obtained of wind-tunnel tests of the National Aerospace Plane (NASP) configuration, which were conducted in the NASA Langley Research Center High Speed Tunnel using a blended body NASP configuration designed by the research center. Static and dynamic stability characteristics were measured at Mach numbers 0.3, 0.6, and 0.8. In addition to tests of the baseline configuration, component buildup tests with a canard surface and with a body flap were carried out. Results demonstrated a positive static stability of the baseline configuration, except at the higher angles of attack at Mach 0.8. A good agreement was found between the inphase dynamic parameters and the corresponding static data.

Coseismic flow of frictional melts: insights from mini-AMS measurements on pseudotachylyte

NASA Astrophysics Data System (ADS)

Geissman, J. W.; Leibovitz, N.; Meado, A.; Campbell, L.; Ferre, E. C.

2017-12-01

Fault pseudotachylytes, widely regarded as earthquake fossils, are fascinating rocks that may hold important clues on the physics of seismic rupture and the lubrication of fault planes. Forceful injection of rapidly produced melts along a friction zone typically forms a complex network of veins along the slip zone and at a high angle to the generation plane. The flow patterns of these pseudotachylyte melts remain, however, poorly constrained except in rare cases when billow-like folds or other flow structures are preserved. Recent modifications to the anisotropy of magnetic susceptibility (AMS) method allow new directions of investigations of melt kinematics in pseudotachylyte veins, regardless of whether they are generation or injection veins. Here we present new mini-AMS results based on series of 3.5 mm cubes (≈200 times smaller than classic sample size) of pseudotachylyte veins from the Val Gilba (Italian Alps), the Cima di Gratera (Corsica) and Santa Rosa (California) classic localities. These preliminary analyses demonstrate the potential of this new mini-AMS method in tracking the complex coseismic movement of a low viscosity magma through dynamically deformed conduits. The lack of plastic deformation in pseudotachylyte clasts and along the pseudotachylyte margins supports the hypothesis that the coseismic melt flow pattern is frozen in situ without significant subsolidus deformation.

Two Photon Polymerization of Microneedles for Transdermal Drug Delivery

PubMed Central

Gittard, Shaun D.; Ovsianikov, Aleksandr; Chichkov, Boris N.; Doraiswamy, Anand; Narayan, Roger J.

2010-01-01

Importance of the field Microneedles are small-scale devices that are finding use for transdermal delivery of protein-based pharmacologic agents and nucleic acid-based pharmacologic agents; however, microneedles prepared using conventional microelectronics-based technologies have several shortcomings, which have limited translation of these devices into widespread clinical use. Areas covered in this review Two photon polymerization is a laser-based rapid prototyping technique that has been recently used for direct fabrication of hollow microneedles with a wide variety of geometries. In addition, an indirect rapid prototyping method that involves two photon polymerization and polydimethyl siloxane micromolding has been used for fabrication of solid microneedles with exceptional mechanical properties. What the reader will gain In this review, the use of two photon polymerization for fabricating in-plane and out-of-plane hollow microneedle arrays is described. The use of two photon polymerization-micromolding for fabrication of solid microneedles is also reviewed. In addition, fabrication of microneedles with antimicrobial properties is discussed; antimicrobial microneedles may reduce the risk of infection associated with formation of channels through the stratum corneum. Take home message It is anticipated that the use of two photon polymerization as well as two photon polymerization-micromolding for fabrication of microneedles and other microstructured drug delivery devices will increase over the coming years. PMID:20205601

Can CT-based patient-matched instrumentation achieve consistent rotational alignment in knee arthroplasty?

PubMed

Tibesku, C O; Innocenti, B; Wong, P; Salehi, A; Labey, L

2012-02-01

Long-term success of contemporary total knee replacements relies to a large extent on proper implant alignment. This study was undertaken to test whether specimen-matched cutting blocks based on computed axial tomography (CT) scans could provide accurate rotational alignment of the femoral component. CT scans of five fresh frozen full leg cadaver specimens, equipped with infrared reflective markers, were used to produce a specimen-matched femoral cutting block. Using those blocks, the bone cuts were made to implant a bi-compartmental femoral component. Rotational alignment of the components in the horizontal plane was determined using an optical measurement system and compared with all relevant rotational reference axes identified on the CT scans. Average rotational alignment for the bi-compartmental component in the horizontal plane was 1.9° (range 0°-6.3°; standard deviation 2.6°). One specimen that showed the highest deviation from the planned alignment also featured a completely degraded medial articular surface. The CT-based specimen-matched cutting blocks achieved good rotational alignment accuracy except for one specimen with badly damaged cartilage. In such cases, imaging techniques that visualize the cartilage layer might be more suitable to design cutting blocks, as they will provide a better fit and increased surface support.

Paediatric forearm fractures: functional outcome of conservative treatment.

PubMed

Tarmuzi, Nazari Ahmad; Abdullah, Shalimar; Osman, Zulkiflee; Das, Srijit

2009-01-01

Forearm fractures are common in the paediatric age group. Closed reduction and casting are the primary means of treatment in over 90% of these fractures. Resultant deformities are usually a product of indirect trauma involving angular loading combined with rotational deformity and fragment displacement. Retrospectively, 48 patients aged between 4 to 12 years with forearm fractures, were treated conservatively with closed reduction and a cast during a 2-year period. Functional outcomes were measured in terms of pronation and supination. All fractures united before the final visit. Most forearm bone fractures were complete fractures at the mid shaft. Eighty-six percent of the patients had excellent functional outcomes and none had poor outcomes. There were significantly reduced angles of deformities before and after treatment (p < 0.05). Radiographically, in the frontal plane, 57.1% of radius and 73.9% of ulnar fractures achieved perfect reduction (i.e. a degree of deformity of less than 5 degrees). However, in the lateral plane, there were fewer perfect reductions for the radius and ulna, at 14.6% and 54.3%, respectively. All except for one patient were satisfied with the outcomes. The level of fracture did not influence the outcomes. Conservative treatment is still an acceptable form of treatment especially for stable forearm fractures in children achieving excellent outcomes (Tab. 1, Fig. 7, Ref. 20).

Exploiting dimensionality and defect mitigation to create tunable microwave dielectrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Che-Hui; Orloff, Nathan; Birol, Turan

2013-01-01

The miniaturization and integration of frequency-agile microwave circuits tunable filters, resonators, phase shifters and more with microelectronics offers tantalizing device possibilities, yet requires thin films whose dielectric constant at GHz frequencies can be tuned by applying a quasi-static electric field . Appropriate systems, e.g., BaxSr1 xTiO3, have a paraelectric-to-ferroelectric transition just below ambient temperature, providing high tunability1 . Unfortunately such films suffer significant losses arising from defects. Recognizing that progress is stymied by dielectric loss, we start with a system with exceptionally low loss Srn+1TinO3n+1 phases , where (SrO)2 crystallographic shear , planes provide an alternative to point defect formationmore » for accommodating non-stoichiometry , . Here, we report the experimental realization of a highly tunable ground state arising from the emergence of a local ferroelectric instability in biaxially strained Srn+1TinO3n+1 phases with n 3 at frequencies up to 120 GHz. In contrast to traditional methods of modifying ferroelectrics doping or strain in this rather unique system increasing the separation between the (SrO)2 planes bolsters the local ferroelectric instability. This new control parameter, n, can be exploited to achieve a figure of merit at room temperature that rivals all known tunable microwave dielectrics.« less

The effect of age and speed on foot and ankle kinematics assessed using a 4-segment foot model.

PubMed

van Hoeve, Sander; Leenstra, Bernard; Willems, Paul; Poeze, Martijn; Meijer, Kenneth

2017-09-01

The effects of age and speed on foot and ankle kinematics in gait studies using foot models are not fully understood, whereas this can have significant influence. We analyzed these variables with the 4-segment Oxford foot model. Twenty-one healthy subjects (aged 20-65 years) were recruited for gait analysis. The effect of speed on foot and ankle kinematics was assessed by comparing results during slow walking and fast walking. To assess the effect of age, a group of 13 healthy young adults (aged 20-24 years) were compared with a group of 8 older adults (aged 53-65 years). Also, the interaction between age and speed was analyzed. Regarding speed, there was a significant difference between forefoot/hindfoot motion in the sagittal plane (flexion/extension) during both loading- and push-off phase (P = .004, P < .001). Between hindfoot/tibia, there was a significant difference for all parameters except for motion in the sagittal plane (flexion/extension) during push-off phase (P = .5). Age did not significantly influence kinematics. There was no interaction between age and speed. Our analysis found that speed significantly influenced the kinematic outcome parameters. This was more pronounced in the ankle joint. In contrast, no significant differences were found between younger and older healthy subjects.

Damage during the 6-24 February 2017 Ayvacık (Çanakkale) earthquake swarm

NASA Astrophysics Data System (ADS)

Livaoğlu, Ramazan; Ömer Timurağaoğlu, Mehmet; Serhatoğlu, Cavit; Sami Döven, Mahmud

2018-03-01

On 6 February 2017 an earthquake swarm began at the western end of Turkey. This was the first recorded swarm in the Çanakkale region since continuous seismic monitoring began in 1970. The number of earthquakes located increased during the following 10 days. This paper describes the output of a survey carried out in the earthquake-prone towns in the area of Ayvacık, Çanakkale, Turkey, in February 2017 after the earthquakes. Observations of traditional buildings were made on site at the rural area of Ayvacık. A description of the main structural features and their effects on the most frequently viewed damage modes were made according to in-plane, out-of-plane behavior of the wall regarding construction practice, connection type, etc. It was found that there were no convenient connections like cavity ties or sufficient mortar strength resulting in decreased and/or lack of lateral load bearing capacity of the wall. Furthermore, distribution maps of damaged/undamaged buildings according to villages, damage ratios, structures and damage levels are generated. Distribution maps showed that damage ratio of structures is higher in villages close to epicenter and decrease away from epicenter except Gülpınar, where past experiences and development level affect the construction quality.

Seismic valve as the main mechanism for sedimentary fluid entrapment within extensional basin: example of the Lodève Permian Basin (Hérault, South of France).

NASA Astrophysics Data System (ADS)

Laurent, D.; Lopez, M.; Chauvet, A.; Imbert, P.; Sauvage, A. C.; Martine, B.; Thomas, M.

2014-12-01

During syn-sedimentary burial in basin, interstitial fluids initially trapped within the sedimentary pile are easily moving under overpressure gradient. Indeed, they have a significant role on deformation during basin evolution, particularly on fault reactivation. The Lodève Permian Basin (Hérault, France) is an exhumed half graben with exceptional outcrop conditions providing access to barite-sulfides mineralized systems and hydrocarbon trapped into rollover faults of the basin. Architectural studies shows a cyclic infilling of fault zone and associated S0-parallel veins according to three main fluid events during dextral/normal faulting. Contrasting fluid entrapment conditions are deduced from textural analysis, fluid inclusion microthermometry and sulfide isotope geothermometer: (i) the first stage is characterized by an implosion breccia cemented by silicifications and barite during abrupt pressure drop within fault zone; (ii) the second stage consists in succession of barite ribbons precipitated under overpressure fluctuations, derived from fault-valve action, with reactivation planes formed by sulphide-rich micro-shearing structures showing normal movement; and (iii) the third stage is associated to the formation of dextral strike-slip pull-apart infilling by large barite crystals and contemporary hydrocarbons under suprahydrostatic pressure values. Microthermometry, sulfide and strontium isotopic compositions of the barite-sulfides veins indicate that all stages were formed by mixing between deep basinal fluids at 230°C, derived from cinerite dewatering, and formation water from overlying sedimentary cover channelized trough fault planes. We conclude to a polyphase history of fluid trapping during Permian synrift formation of the basin: (i) a first event, associated with the dextral strike-slip motion on faults, leads to a first sealing of the fault zone; (ii) periodic reactivations of fault planes and bedding-controlled shearing form the main mineralized ore bodies by the single action of fluid overpressure fluctuations, undergoing changes in local stress distribution and (iii) a final tectonic activation of fault linked to last basinal fluid and hydrocarbon migration during which shear stress restoration on fault plane is faster than fluid pressure build-up.

Confined disordered strictly jammed binary sphere packings

NASA Astrophysics Data System (ADS)

Chen, D.; Torquato, S.

2015-12-01

Disordered jammed packings under confinement have received considerably less attention than their bulk counterparts and yet arise in a variety of practical situations. In this work, we study binary sphere packings that are confined between two parallel hard planes and generalize the Torquato-Jiao (TJ) sequential linear programming algorithm [Phys. Rev. E 82, 061302 (2010), 10.1103/PhysRevE.82.061302] to obtain putative maximally random jammed (MRJ) packings that are exactly isostatic with high fidelity over a large range of plane separation distances H , small to large sphere radius ratio α , and small sphere relative concentration x . We find that packing characteristics can be substantially different from their bulk analogs, which is due to what we term "confinement frustration." Rattlers in confined packings are generally more prevalent than those in their bulk counterparts. We observe that packing fraction, rattler fraction, and degree of disorder of MRJ packings generally increase with H , though exceptions exist. Discontinuities in the packing characteristics as H varies in the vicinity of certain values of H are due to associated discontinuous transitions between different jammed states. When the plane separation distance is on the order of two large-sphere diameters or less, the packings exhibit salient two-dimensional features; when the plane separation distance exceeds about 30 large-sphere diameters, the packings approach three-dimensional bulk packings. As the size contrast increases (as α decreases), the rattler fraction dramatically increases due to what we call "size-disparity" frustration. We find that at intermediate α and when x is about 0.5 (50-50 mixture), the disorder of packings is maximized, as measured by an order metric ψ that is based on the number density fluctuations in the direction perpendicular to the hard walls. We also apply the local volume-fraction variance στ2(R ) to characterize confined packings and find that these packings possess essentially the same level of hyperuniformity as their bulk counterparts. Our findings are generally relevant to confined packings that arise in biology (e.g., structural color in birds and insects) and may have implications for the creation of high-density powders and improved battery designs.

Zigzag antiferromagnetic ground state with anisotropic correlation lengths in the quasi-two-dimensional honeycomb lattice compound N a2C o2Te O6

NASA Astrophysics Data System (ADS)

Bera, A. K.; Yusuf, S. M.; Kumar, Amit; Ritter, C.

2017-03-01

The crystal structure, magnetic ground state, and the temperature-dependent microscopic spin-spin correlations of the frustrated honeycomb lattice antiferromagnet N a2C o2Te O6 have been investigated by powder neutron diffraction. A long-range antiferromagnetic (AFM) ordering has been found below TN˜24.8 K . The magnetic ground state, determined to be zigzag antiferromagnetic and characterized by a propagation vector k =(1 /2 0 0 ) , occurs due to the competing exchange interactions up to third-nearest neighbors within the honeycomb lattice. The exceptional existence of a limited magnetic correlation length along the c axis (perpendicular to the honeycomb layers in the a b planes) has been found even at 1.8 K, well below the TN˜24.8 K . The observed limited correlation along the c axis is explained by the disorder distribution of the Na ions within the intermediate layers between honeycomb planes. The reduced ordered moments mCo (1 )=2.77 (3 ) μB/C o2 + and mCo (2 )=2.45 (2 ) μB/C o2 + at 1.8 K reflect the persistence of spin fluctuations in the ordered state. Above TN˜24.8 K , the presence of short-range magnetic correlations, manifested by broad diffuse magnetic peaks in the diffraction patterns, has been found. Reverse Monte Carlo analysis of the experimental diffuse magnetic scattering data reveals that the spin correlations are mainly confined within the two-dimensional honeycomb layers (a b plane) with a correlation length of ˜12 Å at 25 K. The nature of the spin arrangements is found to be similar in both the short-range and long-range ordered magnetic states. This implies that the short-range correlation grows with decreasing temperature and leads to the zigzag AFM ordering at T ≤TN . The present study provides a comprehensive picture of the magnetic correlations over the temperature range above and below the TN and their relation to the crystal structure. The role of intermediate soft Na layers on the magnetic coupling between honeycomb planes is discussed.

Dosimetric Characteristics of Wedged Fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sidhu, N.P.S.; Breitman, Karen

2015-01-15

The beam characteristics of the wedged fields in the nonwedged planes (planes normal to the wedged planes) were studied for 6 MV and 15 MV x-ray beams. A method was proposed for determining the maximum field length of a wedged field that can be used in the nonwedged plane without introducing undesirable alterations in the dose distributions of these fields. The method requires very few measurements. The relative wedge factors of 6 MV and 15 MV X-rays were determined for wedge filters of nominal wedge angles of 15°, 30°, 45°, and 60° as a function of depth and field size.more » For a 6 MV beam the relative wedge factors determined for a field size of 10 × 10 cm{sup 2} for 30°, 45°, and 60° wedge filters can be used for various field sizes ranging from 4 cm{sup 2} to 20 cm{sup 2} (except for the 60° wedge for which the maximum field size that can be used is 15 × 20 cm{sup 2}) without introducing errors in the dosimetric calculations of more than 0.5% for depths up to 20 cm and 1% for depths up to 30 cm. For the 15° wedge filter the relative wedge factor for a field size of 10 × 10 cm{sup 2} can be used over the same range of field sizes by introducing slightly higher error, 0.5% for depths up to 10 cm and 1% for depths up to 30 cm. For a 15 MV beam the maximum magnitude of the relative wedge factors for 45° and 60° lead wedges is of the order of 1%, and it is not important clinically to apply a correction of that magnitude. For a 15 MV beam the relative wedge factors determined for a field size of 6 × 6 cm{sup 2} for the 15° and 30° steel wedges can be used over a range of field sizes from 4 cm{sup 2} to 20 cm{sup 2} without causing dosimetric errors greater than 0.5% for depths up to 10 cm.« less

Multifrequency observations of the radio continuum emission from NGC 253. 1: Magnetic fields and rotation measures in the bar and halo

NASA Astrophysics Data System (ADS)

Beck, R.; Carilli, C. L.; Holdaway, M. A.; Klein, U.

1994-12-01

Radio continuum observations of the spiral galaxy NGC 253 with the Effelsberg and Very Large Array (VLA) telescopes reveal polarized emission from the bar and halo regions. Within the bar Faraday depolarization is strong at 1.5 and 5 GHz, due to ionized gas with ne approximately equal 0.1 - 3/cu cm which is mixed with turbulent magnetic fields of approximately equal 17 microG estimated strength. Even at 10 GHz the degree of polarization in the bar is low (only approximately equal 5% east and approximately equal 2% west of the nucleus) due to beam depolarization by unresolved tangled fields. In contrast, the magnetic fields in the halo are highly uniform, as indicated by fractional polarizations up to 40% at 10 GHz. Faraday depolarization in the halo at 1.5 GHz calls for a warm, clumpy gas component with ne approximately equal 0.02/cu cm and approximately equal 6 microG turbulent fields. We detected Faraday rotation in the bar, with rotation measures absolute value of RM approximately equal 100 rad/sq m (between 10 and 5 GHz) having different signs east and west of the nucleus. Below 5 GHz Faraday rotation is strongly reduced by the limited transparency for polarized emission in the bar. Faraday rotation in the halo in two regions at approximately 5 kpc above and below the plane with RM approximately equal -7 rad/sq m between 10 and 1.5 GHz can be ascribed to hot gas with mean value of ne approximately equal 0.002/cu cm and uniform fields along the line of sight of mean value of Bu parallel approximately equal -2 microG. The magnetic field structure in the bar and halo of NGC 253 is best described by the quadrupole-type dynamo mode SO, with a ring-like field in the bar and a field mainly parallel to the plane in a co-rotating halo. A major perturbation occurs in the east where the field is perpendicular to the plane and follows a 'spur'. The galactic wind is suppressed by the dominating plane-parallel field, except along the spur.

An automatic scaling method for obtaining the trace and parameters from oblique ionogram based on hybrid genetic algorithm

NASA Astrophysics Data System (ADS)

Song, Huan; Hu, Yaogai; Jiang, Chunhua; Zhou, Chen; Zhao, Zhengyu; Zou, Xianjian

2016-12-01

Scaling oblique ionogram plays an important role in obtaining ionospheric structure at the midpoint of oblique sounding path. The paper proposed an automatic scaling method to extract the trace and parameters of oblique ionogram based on hybrid genetic algorithm (HGA). The extracted 10 parameters come from F2 layer and Es layer, such as maximum observation frequency, critical frequency, and virtual height. The method adopts quasi-parabolic (QP) model to describe F2 layer's electron density profile that is used to synthesize trace. And it utilizes secant theorem, Martyn's equivalent path theorem, image processing technology, and echoes' characteristics to determine seven parameters' best fit values, and three parameter's initial values in QP model to set up their searching spaces which are the needed input data of HGA. Then HGA searches the three parameters' best fit values from their searching spaces based on the fitness between the synthesized trace and the real trace. In order to verify the performance of the method, 240 oblique ionograms are scaled and their results are compared with manual scaling results and the inversion results of the corresponding vertical ionograms. The comparison results show that the scaling results are accurate or at least adequate 60-90% of the time.

Lateral Penumbra Modelling Based Leaf End Shape Optimization for Multileaf Collimator in Radiotherapy

PubMed Central

Zhou, Dong; Zhang, Hui; Ye, Peiqing

2016-01-01

Lateral penumbra of multileaf collimator plays an important role in radiotherapy treatment planning. Growing evidence has revealed that, for a single-focused multileaf collimator, lateral penumbra width is leaf position dependent and largely attributed to the leaf end shape. In our study, an analytical method for leaf end induced lateral penumbra modelling is formulated using Tangent Secant Theory. Compared with Monte Carlo simulation and ray tracing algorithm, our model serves well the purpose of cost-efficient penumbra evaluation. Leaf ends represented in parametric forms of circular arc, elliptical arc, Bézier curve, and B-spline are implemented. With biobjective function of penumbra mean and variance introduced, genetic algorithm is carried out for approximating the Pareto frontier. Results show that for circular arc leaf end objective function is convex and convergence to optimal solution is guaranteed using gradient based iterative method. It is found that optimal leaf end in the shape of Bézier curve achieves minimal standard deviation, while using B-spline minimum of penumbra mean is obtained. For treatment modalities in clinical application, optimized leaf ends are in close agreement with actual shapes. Taken together, the method that we propose can provide insight into leaf end shape design of multileaf collimator. PMID:27110274

Two- to three-dimensional crossover in a dense electron liquid in silicon

NASA Astrophysics Data System (ADS)

Matmon, Guy; Ginossar, Eran; Villis, Byron J.; Kölker, Alex; Lim, Tingbin; Solanki, Hari; Schofield, Steven R.; Curson, Neil J.; Li, Juerong; Murdin, Ben N.; Fisher, Andrew J.; Aeppli, Gabriel

2018-04-01

Doping of silicon via phosphine exposures alternating with molecular beam epitaxy overgrowth is a path to Si:P substrates for conventional microelectronics and quantum information technologies. The technique also provides a well-controlled material for systematic studies of two-dimensional lattices with a half-filled band. We show here that for a dense (ns=2.8 ×1014 cm-2) disordered two-dimensional array of P atoms, the full field magnitude and angle-dependent magnetotransport is remarkably well described by classic weak localization theory with no corrections due to interaction. The two- to three-dimensional crossover seen upon warming can also be interpreted using scaling concepts developed for anistropic three-dimensional materials, which work remarkably except when the applied fields are nearly parallel to the conducting planes.

Application of various elastic thin shell theories to blood flow problems

NASA Technical Reports Server (NTRS)

1972-01-01

Some existing theories, on elastic thin shells, are reviewed to ascertain their influence on the computation of phase velocities in fluid filled cylinders representing certain aspects of the behavior of arteries and veins in vivo. For physiologically meaningful parameters, including moderately large in plane prestrain that occurs in mammals, the results suggest that with one exception, the small differences in the formulations exercise little influence on the phase velocities. However, it is demonstrated that inclusion of the forces induced by the rotation of the hydrostatic pressure is essential or significantly erroneous torsional wave speeds result. Also the introduction of moderate implane prestrains that are present in living mammals is shown to lead to nonselfadjoint differential equations of motion, whose biorthogonal eigenvectors differ slightly from each other.

Interplanetary Fast Shocks and Associated Drivers Observed through the Twenty-Third Solar Minimum by WIND Over its First 2.5 Years

NASA Technical Reports Server (NTRS)

Mariani, F.; Berdichevsky, D.; Szabo, A.; Lepping, R. P.; Vinas, A. F.

1999-01-01

A list of the interplanetary (IP) shocks observed by WIND from its launch (in November 1994) to May 1997 is presented. Forty two shocks were identified. The magnetohydrodynamic nature of the shocks is investigated, and the associated shock parameters and their uncertainties are accurately computed using a practical scheme which combines two techniques. These techniques are a combination of the "pre-averaged" magnetic-coplanarity, velocity-coplanarity, and the Abraham-Schrauner-mixed methods, on the one hand, and the Vinas and Scudder [1986] technique for solving the non-linear least-squares Rankine-Hugoniot shock equations, on the other. Within acceptable limits these two techniques generally gave the same results, with some exceptions. The reasons for the exceptions are discussed. It is found that the mean strength and rate of occurrence of the shocks appears to correlated with the solar cycle. Both showed a decrease in 1996 coincident with the time of the lowest ultraviolet solar radiance, indicative of solar minimum and start of solar cycle 23, which began around June 1996. Eighteen shocks appeared to be associated with corotating interaction regions (CIRs). The distribution of their shock normals showed a mean direction peaking in the ecliptic plane and with a longitude (phi(sub n)) in that plane between perpendicular to the Parker spiral and radial from the Sun. When grouped according to the sense of the direction of propagation of the shocks the mean azimuthal (longitude) angle in GSE coordinates was approximately 194 deg for the fast-forward and approximately 20 deg for the fast-reverse shocks. Another 16 shocks were determined to be driven by solar transients, including magnetic clouds. These shocks had a broader distribution of normal directions than those of the CIR cases with a mean direction close to the Sun-Earth line. Eight shocks of unknown origin had normal orientation well off the ecliptic plane. No shock propagated with longitude phi(sub n) >= 220 +/- 10 deg, this would suggest strong hindrance to the propagation of shocks contra a rather tightly winding Parker spiral. Examination of the obliquity angle theta(sub Bn) (that between the shock normal and the upstream interplanetary magnetic field) for the full set of shocks revealed that about 58% was quasi-perpendicular, and some were very nearly perpendicular. About 32% of the shocks were oblique, and the rest (only 10%) were quasi-parallel, with one on Dec. 9, 1996 that showed field pulsations. Small uncertainty in the estimated angle theta(sub Bn) was obtained for about 10 shocks with magnetosonic Mach numbers between 1 and 2, hopefully significantly contributing to studies researching particle acceleration mechanisms at IP shocks, and to investigations where accurate values of theta(sub Bn) are crucial.

Comparative long-term trend analysis of daily weather conditions with daily pollen concentrations in Brussels, Belgium

NASA Astrophysics Data System (ADS)

Bruffaerts, Nicolas; De Smedt, Tom; Delcloo, Andy; Simons, Koen; Hoebeke, Lucie; Verstraeten, Caroline; Van Nieuwenhuyse, An; Packeu, Ann; Hendrickx, Marijke

2018-03-01

A clear rise in seasonal and annual temperatures, a gradual increase of total radiation, and a relative trend of change in seasonal precipitation have been observed for the last four decades in Brussels (Belgium). These local modifications may have a direct and indirect public health impact by altering the timing and intensity of allergenic pollen seasons. In this study, we assessed the statistical correlations (Spearman's test) between pollen concentration and meteorological conditions by using long-term daily datasets of 11 pollen types (8 trees and 3 herbaceous plants) and 10 meteorological parameters observed in Brussels between 1982 and 2015. Furthermore, we analyzed the rate of change in the annual cycle of the same selected pollen types by the Mann-Kendall test. We revealed an overall trend of increase in daily airborne tree pollen (except for the European beech tree) and an overall trend of decrease in daily airborne pollen from herbaceous plants (except for Urticaceae). These results revealed an earlier onset of the flowering period for birch, oak, ash, plane, grasses, and Urticaceae. Finally, the rates of change in pollen annual cycles were shown to be associated with the rates of change in the annual cycles of several meteorological parameters such as temperature, radiation, humidity, and rainfall.

Comparative long-term trend analysis of daily weather conditions with daily pollen concentrations in Brussels, Belgium.

PubMed

Bruffaerts, Nicolas; De Smedt, Tom; Delcloo, Andy; Simons, Koen; Hoebeke, Lucie; Verstraeten, Caroline; Van Nieuwenhuyse, An; Packeu, Ann; Hendrickx, Marijke

2018-03-01

A clear rise in seasonal and annual temperatures, a gradual increase of total radiation, and a relative trend of change in seasonal precipitation have been observed for the last four decades in Brussels (Belgium). These local modifications may have a direct and indirect public health impact by altering the timing and intensity of allergenic pollen seasons. In this study, we assessed the statistical correlations (Spearman's test) between pollen concentration and meteorological conditions by using long-term daily datasets of 11 pollen types (8 trees and 3 herbaceous plants) and 10 meteorological parameters observed in Brussels between 1982 and 2015. Furthermore, we analyzed the rate of change in the annual cycle of the same selected pollen types by the Mann-Kendall test. We revealed an overall trend of increase in daily airborne tree pollen (except for the European beech tree) and an overall trend of decrease in daily airborne pollen from herbaceous plants (except for Urticaceae). These results revealed an earlier onset of the flowering period for birch, oak, ash, plane, grasses, and Urticaceae. Finally, the rates of change in pollen annual cycles were shown to be associated with the rates of change in the annual cycles of several meteorological parameters such as temperature, radiation, humidity, and rainfall.

Exploiting dimensionality and defect mitigation to create tunable microwave dielectrics

NASA Astrophysics Data System (ADS)

Lee, Che-Hui; Orloff, Nathan D.; Birol, Turan; Zhu, Ye; Goian, Veronica; Rocas, Eduard; Haislmaier, Ryan; Vlahos, Eftihia; Mundy, Julia A.; Kourkoutis, Lena F.; Nie, Yuefeng; Biegalski, Michael D.; Zhang, Jingshu; Bernhagen, Margitta; Benedek, Nicole A.; Kim, Yongsam; Brock, Joel D.; Uecker, Reinhard; Xi, X. X.; Gopalan, Venkatraman; Nuzhnyy, Dmitry; Kamba, Stanislav; Muller, David A.; Takeuchi, Ichiro; Booth, James C.; Fennie, Craig J.; Schlom, Darrell G.

2013-10-01

The miniaturization and integration of frequency-agile microwave circuits--relevant to electronically tunable filters, antennas, resonators and phase shifters--with microelectronics offers tantalizing device possibilities, yet requires thin films whose dielectric constant at gigahertz frequencies can be tuned by applying a quasi-static electric field. Appropriate systems such as BaxSr1-xTiO3 have a paraelectric-ferroelectric transition just below ambient temperature, providing high tunability. Unfortunately, such films suffer significant losses arising from defects. Recognizing that progress is stymied by dielectric loss, we start with a system with exceptionally low loss--Srn+1TinO3n+1 phases--in which (SrO)2 crystallographic shear planes provide an alternative to the formation of point defects for accommodating non-stoichiometry. Here we report the experimental realization of a highly tunable ground state arising from the emergence of a local ferroelectric instability in biaxially strained Srn+1TinO3n+1 phases with n>=3 at frequencies up to 125GHz. In contrast to traditional methods of modifying ferroelectrics--doping or strain--in this unique system an increase in the separation between the (SrO)2 planes, which can be achieved by changing n, bolsters the local ferroelectric instability. This new control parameter, n, can be exploited to achieve a figure of merit at room temperature that rivals all known tunable microwave dielectrics.

A new parallel plate shear cell for in situ real-space measurements of complex fluids under shear flow.

PubMed

Wu, Yu Ling; Brand, Joost H J; van Gemert, Josephus L A; Verkerk, Jaap; Wisman, Hans; van Blaaderen, Alfons; Imhof, Arnout

2007-10-01

We developed and tested a parallel plate shear cell that can be mounted on top of an inverted microscope to perform confocal real-space measurements on complex fluids under shear. To follow structural changes in time, a plane of zero velocity is created by letting the plates move in opposite directions. The location of this plane is varied by changing the relative velocities of the plates. The gap width is variable between 20 and 200 microm with parallelism better than 1 microm. Such a small gap width enables us to examine the total sample thickness using high numerical aperture objective lenses. The achieved shear rates cover the range of 0.02-10(3) s(-1). This shear cell can apply an oscillatory shear with adjustable amplitude and frequency. The maximum travel of each plate equals 1 cm, so that strains up to 500 can be applied. For most complex fluids, an oscillatory shear with such a large amplitude can be regarded as a continuous shear. We measured the flow profile of a suspension of silica colloids in this shear cell. It was linear except for a small deviation caused by sedimentation. To demonstrate the excellent performance and capabilities of this new setup we examined shear induced crystallization and melting of concentrated suspensions of 1 microm diameter silica colloids.

The effect of age and speed on foot and ankle kinematics assessed using a 4-segment foot model

PubMed Central

van Hoeve, Sander; Leenstra, Bernard; Willems, Paul; Poeze, Martijn; Meijer, Kenneth

2017-01-01

Abstract Background: The effects of age and speed on foot and ankle kinematics in gait studies using foot models are not fully understood, whereas this can have significant influence. We analyzed these variables with the 4-segment Oxford foot model. Methods: Twenty-one healthy subjects (aged 20–65 years) were recruited for gait analysis. The effect of speed on foot and ankle kinematics was assessed by comparing results during slow walking and fast walking. To assess the effect of age, a group of 13 healthy young adults (aged 20–24 years) were compared with a group of 8 older adults (aged 53–65 years). Also, the interaction between age and speed was analyzed. Results: Regarding speed, there was a significant difference between forefoot/hindfoot motion in the sagittal plane (flexion/extension) during both loading- and push-off phase (P = .004, P < .001). Between hindfoot/tibia, there was a significant difference for all parameters except for motion in the sagittal plane (flexion/extension) during push-off phase (P = .5). Age did not significantly influence kinematics. There was no interaction between age and speed. Conclusion: Our analysis found that speed significantly influenced the kinematic outcome parameters. This was more pronounced in the ankle joint. In contrast, no significant differences were found between younger and older healthy subjects. PMID:28858109

Kinematic repeatability of a multi-segment foot model for dance.

PubMed

Carter, Sarah L; Sato, Nahoko; Hopper, Luke S

2018-03-01

The purpose of this study was to determine the intra and inter-assessor repeatability of a modified Rizzoli Foot Model for analysing the foot kinematics of ballet dancers. Six university-level ballet dancers performed the movements; parallel stance, turnout plié, turnout stance, turnout rise and flex-point-flex. The three-dimensional (3D) position of individual reflective markers and marker triads was used to model the movement of the dancers' tibia, entire foot, hindfoot, midfoot, forefoot and hallux. Intra and inter-assessor reliability demonstrated excellent (ICC ≥ 0.75) repeatability for the first metatarsophalangeal joint in the sagittal plane. Intra-assessor reliability demonstrated excellent (ICC ≥ 0.75) repeatability during flex-point-flex across all inter-segmental angles except for the tibia-hindfoot and hindfoot-midfoot frontal planes. Inter-assessor repeatability ranged from poor to excellent (0.5 > ICC ≥ 0.75) for the 3D segment rotations. The most repeatable measure was the tibia-foot dorsiflexion/plantar flexion articulation whereas the least repeatable measure was the hindfoot-midfoot adduction/abduction articulation. The variation found in the inter-assessor results is likely due to inconsistencies in marker placement. This 3D dance specific multi-segment foot model provides insight into which kinematic measures can be reliably used to ascertain in vivo technical errors and/or biomechanical abnormalities in a dancer's foot motion.

Crack classification and evolution in anisotropic shale during cyclic loading tests by acoustic emission

NASA Astrophysics Data System (ADS)

Wang, Miaomiao; Tan, Chengxuan; Meng, Jing; Yang, Baicun; Li, Yuan

2017-08-01

Characterization and evolution of the cracking mode in shale formation is significant, as fracture networks are an important element in shale gas exploitation. In this study we determine the crack modes and evolution in anisotropic shale under cyclic loading using the acoustic emission (AE) parameter-analysis method based on the average frequency and RA (rise-time/amplitude) value. Shale specimens with bedding-plane orientations parallel and perpendicular to the axial loading direction were subjected to loading cycles with increasing peak values until failure occurred. When the loading was parallel to the bedding plane, most of the cracks at failure were shear cracks, while tensile cracks were dominant in the specimens that were loaded normal to the bedding direction. The evolution of the crack mode in the shale specimens observed in the loading-unloading sequence except for the first cycle can be divided into three stages: (I) no or several cracks (AE events) form as a result of the Kaiser effect, (II) tensile and shear cracks increase steadily at nearly equal proportions, (III) tensile cracks and shear cracks increase abruptly, with more cracks forming in one mode than in the other. As the dominant crack motion is influenced by the bedding, the failure mechanism is discussed based on the evolution of the different crack modes. Our conclusions can increase our understanding of the formation mechanism of fracture networks in the field.

Impact of oleylamine: Oleic acid ratio on the morphology of yttria nanomaterials

DOE PAGES

Treadwell, LaRico J.; Boyle, Timothy J.; Bell, Nelson S.; ...

2017-03-31

In this paper, the impact on the final morphology of yttria (Y 2O 3) nanoparticles from different ratios (100/0, 90/10, 65/35, and 50/50) of oleylamine (ON) and oleic acid (OA) via a solution precipitation route has been determined. In all instances, powder X-ray diffraction indicated that the cubic Y 2O 3 phase (PDF #00-025-1200) with the space group I-3a (206) had been formed. Analysis of the collected FTIR data revealed the presence of stretches and bends consistent with ON and OA, for all ratios investigated, except the 100/0. Transmission electron microscopy images revealed regular and elongated hexagons were produced formore » the ON (100/0) sample. As OA was added, the nanoparticle morphology changed to lamellar pillars (90/10), then irregular particles (65/35), and finally plates (50/50). The formation of the hexagonal-shaped nanoparticles was determined to be due to the preferential adsorption of ON onto the {101} planes. As OA was added to the reaction mixture, it was found that the {111} planes were preferentially coated, replacing ON from the surface, resulting in the various morphologies noted. The roles of the ratio of ON/OA in the synthesis of the nanocrystals were elucidated in the formation of the various Y 2O 3 morphologies, as well as a possible growth mechanism based on the experimental data.« less

Revision of the Li13Si4 structure.

PubMed

Zeilinger, Michael; Fässler, Thomas F

2013-11-06

Besides Li17Si4, Li16.42Si4, and Li15Si4, another lithium-rich representative in the Li-Si system is the phase Li13Si4 (trideca-lithium tetra-silicide), the structure of which has been determined previously [Frank et al. (1975 ▶). Z. Naturforsch. Teil B, 30, 10-13]. A careful analysis of X-ray diffraction patterns of Li13Si4 revealed discrepancies between experimentally observed and calculated Bragg positions. Therefore, we redetermined the structure of Li13Si4 on the basis of single-crystal X-ray diffraction data. Compared to the previous structure report, decisive differences are (i) the introduction of a split position for one Li site [occupancy ratio 0.838 (7):0.162 (7)], (ii) the anisotropic refinement of atomic displacement parameters for all atoms, and (iii) a high accuracy of atom positions and unit-cell parameters. The asymmetric unit of Li13Si4 contains two Si and seven Li atoms. Except for one Li atom situated on a site with symmetry 2/m, all other atoms are on mirror planes. The structure consists of isolated Si atoms as well as Si-Si dumbbells surrounded by Li atoms. Each Si atom is either 12- or 13-coordinated. The isolated Si atoms are situated in the ab plane at z = 0 and are strictly separated from the Si-Si dumbbells at z = 0.5.

Oscillating potential well in the complex plane and the adiabatic theorem

NASA Astrophysics Data System (ADS)

Longhi, Stefano

2017-10-01

A quantum particle in a slowly changing potential well V (x ,t ) =V ( x -x0(ɛ t ) ) , periodically shaken in time at a slow frequency ɛ , provides an important quantum mechanical system where the adiabatic theorem fails to predict the asymptotic dynamics over time scales longer than ˜1 /ɛ . Specifically, we consider a double-well potential V (x ) sustaining two bound states spaced in frequency by ω0 and periodically shaken in a complex plane. Two different spatial displacements x0(t ) are assumed: the real spatial displacement x0(ɛ t ) =A sin(ɛ t ) , corresponding to ordinary Hermitian shaking, and the complex one x0(ɛ t ) =A -A exp(-i ɛ t ) , corresponding to non-Hermitian shaking. When the particle is initially prepared in the ground state of the potential well, breakdown of adiabatic evolution is found for both Hermitian and non-Hermitian shaking whenever the oscillation frequency ɛ is close to an odd resonance of ω0. However, a different physical mechanism underlying nonadiabatic transitions is found in the two cases. For the Hermitian shaking, an avoided crossing of quasienergies is observed at odd resonances and nonadiabatic transitions between the two bound states, resulting in Rabi flopping, can be explained as a multiphoton resonance process. For the complex oscillating potential well, breakdown of adiabaticity arises from the appearance of Floquet exceptional points at exact quasienergy crossing.

The Balance of Excitatory and Inhibitory Synaptic Inputs for Coding Sound Location

PubMed Central

Ono, Munenori

2014-01-01

The localization of high-frequency sounds in the horizontal plane uses an interaural-level difference (ILD) cue, yet little is known about the synaptic mechanisms that underlie processing this cue in the inferior colliculus (IC) of mouse. Here, we study the synaptic currents that process ILD in vivo and use stimuli in which ILD varies around a constant average binaural level (ABL) to approximate sounds on the horizontal plane. Monaural stimulation in either ear produced EPSCs and IPSCs in most neurons. The temporal properties of monaural responses were well matched, suggesting connected functional zones with matched inputs. The EPSCs had three patterns in response to ABL stimuli, preference for the sound field with the highest level stimulus: (1) contralateral; (2) bilateral highly lateralized; or (3) at the center near 0 ILD. EPSCs and IPSCs were well correlated except in center-preferred neurons. Summation of the monaural EPSCs predicted the binaural excitatory response but less well than the summation of monaural IPSCs. Binaural EPSCs often showed a nonlinearity that strengthened the response to specific ILDs. Extracellular spike and intracellular current recordings from the same neuron showed that the ILD tuning of the spikes was sharper than that of the EPSCs. Thus, in the IC, balanced excitatory and inhibitory inputs may be a general feature of synaptic coding for many types of sound processing. PMID:24599475

Impact of oleylamine: Oleic acid ratio on the morphology of yttria nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Treadwell, LaRico J.; Boyle, Timothy J.; Bell, Nelson S.

In this paper, the impact on the final morphology of yttria (Y 2O 3) nanoparticles from different ratios (100/0, 90/10, 65/35, and 50/50) of oleylamine (ON) and oleic acid (OA) via a solution precipitation route has been determined. In all instances, powder X-ray diffraction indicated that the cubic Y 2O 3 phase (PDF #00-025-1200) with the space group I-3a (206) had been formed. Analysis of the collected FTIR data revealed the presence of stretches and bends consistent with ON and OA, for all ratios investigated, except the 100/0. Transmission electron microscopy images revealed regular and elongated hexagons were produced formore » the ON (100/0) sample. As OA was added, the nanoparticle morphology changed to lamellar pillars (90/10), then irregular particles (65/35), and finally plates (50/50). The formation of the hexagonal-shaped nanoparticles was determined to be due to the preferential adsorption of ON onto the {101} planes. As OA was added to the reaction mixture, it was found that the {111} planes were preferentially coated, replacing ON from the surface, resulting in the various morphologies noted. The roles of the ratio of ON/OA in the synthesis of the nanocrystals were elucidated in the formation of the various Y 2O 3 morphologies, as well as a possible growth mechanism based on the experimental data.« less

Identification of 'Point A' as the prevalent source of error in cephalometric analysis of lateral radiographs.

PubMed

Grogger, P; Sacher, C; Weber, S; Millesi, G; Seemann, R

2018-04-10

Deviations in measuring dentofacial components in a lateral X-ray represent a major hurdle in the subsequent treatment of dysgnathic patients. In a retrospective study, we investigated the most prevalent source of error in the following commonly used cephalometric measurements: the angles Sella-Nasion-Point A (SNA), Sella-Nasion-Point B (SNB) and Point A-Nasion-Point B (ANB); the Wits appraisal; the anteroposterior dysplasia indicator (APDI); and the overbite depth indicator (ODI). Preoperative lateral radiographic images of patients with dentofacial deformities were collected and the landmarks digitally traced by three independent raters. Cephalometric analysis was automatically performed based on 1116 tracings. Error analysis identified the x-coordinate of Point A as the prevalent source of error in all investigated measurements, except SNB, in which it is not incorporated. In SNB, the y-coordinate of Nasion predominated error variance. SNB showed lowest inter-rater variation. In addition, our observations confirmed previous studies showing that landmark identification variance follows characteristic error envelopes in the highest number of tracings analysed up to now. Variance orthogonal to defining planes was of relevance, while variance parallel to planes was not. Taking these findings into account, orthognathic surgeons as well as orthodontists would be able to perform cephalometry more accurately and accomplish better therapeutic results. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications.

PubMed

Dong, Jian; Li, Qianqian; Deng, Lianwen

2017-02-10

Ultrawideband (UWB) antennas, as core devices in high-speed wireless communication, are widely applied to mobile handsets, wireless sensor networks, and Internet of Things (IoT). A compact printed monopole antenna for UWB applications with triple band-notched characteristics is proposed in this paper. The antenna has a very compact size of 10 x 16 mm2 and is composed of a square slotted radiation patch and a narrow rectangular ground plane on the back of the substrate. First, by etching a pair of inverted T-shaped slots at the bottom of the radiation patch, one notched band at 5-6 GHz for rejecting the Wireless Local Area Network (WLAN) is generated. Then, by cutting a comb-shaped slot on the top of the radiation patch, a second notched band for rejecting 3.5 GHz Worldwide Interoperability for Microwave Access (WiMAX) is obtained. Further, by cutting a pair of rectangular slots and a C-shaped slot as well as adding a pair of small square parasitic patches at the center of the radiating patch, two separate notched bands for rejecting 5.2 GHz lower WLAN and 5.8 GHz upper WLAN are realized, respectively. Additionally, by integrating the slotted radiation patch with the narrow rectangular ground plane, an enhanced impedance bandwidth can be achieved, especially at the higher band. The antenna consists of linear symmetrical sections only and is easy for fabrication and fine-tuning. The measured results show that the designed antenna provides a wide impedance bandwidth of 150% from 2.12 to 14.80 GHz for VSWR < 2, except for three notched bands of 3.36-4.16, 4.92-5.36, and 5.68-6.0 GHz. Additionally, the antenna exhibits nearly omnidirectional radiation characteristics, low gain at the stopbands, and flat group delay over the whole UWB except at the stopbands. Simulated and experimental results show that the proposed antenna can provide good frequency-domain and time-domain performances at desired UWB frequencies and be an attractive candidate for portable IoT applications.

Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications

PubMed Central

Dong, Jian; Li, Qianqian; Deng, Lianwen

2017-01-01

Ultrawideband (UWB) antennas, as core devices in high-speed wireless communication, are widely applied to mobile handsets, wireless sensor networks, and Internet of Things (IoT). A compact printed monopole antenna for UWB applications with triple band-notched characteristics is proposed in this paper. The antenna has a very compact size of 10 × 16 mm2 and is composed of a square slotted radiation patch and a narrow rectangular ground plane on the back of the substrate. First, by etching a pair of inverted T-shaped slots at the bottom of the radiation patch, one notched band at 5–6 GHz for rejecting the Wireless Local Area Network (WLAN) is generated. Then, by cutting a comb-shaped slot on the top of the radiation patch, a second notched band for rejecting 3.5 GHz Worldwide Interoperability for Microwave Access (WiMAX) is obtained. Further, by cutting a pair of rectangular slots and a C-shaped slot as well as adding a pair of small square parasitic patches at the center of the radiating patch, two separate notched bands for rejecting 5.2 GHz lower WLAN and 5.8 GHz upper WLAN are realized, respectively. Additionally, by integrating the slotted radiation patch with the narrow rectangular ground plane, an enhanced impedance bandwidth can be achieved, especially at the higher band. The antenna consists of linear symmetrical sections only and is easy for fabrication and fine-tuning. The measured results show that the designed antenna provides a wide impedance bandwidth of 150% from 2.12 to 14.80 GHz for VSWR < 2, except for three notched bands of 3.36–4.16, 4.92–5.36, and 5.68–6.0 GHz. Additionally, the antenna exhibits nearly omnidirectional radiation characteristics, low gain at the stopbands, and flat group delay over the whole UWB except at the stopbands. Simulated and experimental results show that the proposed antenna can provide good frequency-domain and time-domain performances at desired UWB frequencies and be an attractive candidate for portable IoT applications. PMID:28208633

Quantifying kinematic differences between land and water during squats, split squats, and single-leg squats in a healthy population.

PubMed

Severin, Anna C; Burkett, Brendan J; McKean, Mark R; Wiegand, Aaron N; Sayers, Mark G L

2017-01-01

Aquatic exercises can be used in clinical and sporting disciplines for both rehabilitation and sports training. However, there is limited knowledge on the influence of water immersion on the kinematics of exercises commonly used in rehabilitation and fitness programs. The aim of this study was to use inertial sensors to quantify differences in kinematics and movement variability of bodyweight squats, split squats, and single-leg squats performed on dry land and whilst immersed to the level of the greater trochanter. During two separate testing sessions, 25 active healthy university students (22.3±2.9 yr.) performed ten repetitions of each exercise, whilst tri-axial inertial sensors (100 Hz) recorded their trunk and lower body kinematics. Repeated-measures statistics tested for differences in segment orientation and speed, movement variability, and waveform patterns between environments, while coefficient of variance was used to assess differences in movement variability. Between-environment differences in segment orientation and speed were portrayed by plotting the mean difference ±95% confidence intervals (CI) throughout the tasks. The results showed that the depth of the squat and split squat were unaffected by the changed environment while water immersion allowed for a deeper single leg squat. The different environments had significant effects on the sagittal plane orientations and speeds for all segments. Water immersion increased the degree of movement variability of the segments in all exercises, except for the shank in the frontal plane, which showed more variability on land. Without compromising movement depth, the aquatic environment induces more upright trunk and shank postures during squats and split squats. The aquatic environment allows for increased squat depth during the single-leg squat, and increased shank motions in the frontal plane. Our observations therefore support the use of water-based squat tasks for rehabilitation as they appear to improve the technique without compromising movement depth.

Effects of Vestibular Loss on Orthostatic Responses to Tilts in the Pitch Plane

NASA Technical Reports Server (NTRS)

Wood, Scott J.; Serrador, Jorge M.; Black, F. Owen; Rupert,Angus H.; Schlegel, Todd T.

2004-01-01

The purpose of this study was to determine the extent to which vestibular loss might impair orthostatic responses to passive tilts in the pitch plane in human subjects. Data were obtained from six subjects having chronic bilateral vestibular loss and six healthy individuals matched for age, gender, and body mass index. Vestibular loss was assessed with a comprehensive battery including dynamic posturography, vestibulo-ocular and optokinetic reflexes, vestibular evoked myogenic potentials, and ocular counterrolling. Head up tilt tests were conducted using a motorized two-axis table that allowed subjects to be tilted in the pitch plane from either a supine or prone body orientation at a slow rate (8 deg/s). The sessions consisted of three tilts, each consisting of20 min rest in a horizontal position, tilt to 80 deg upright for 10 min, and then return to the horizontal position for 5 min. The tilts were performed in darkness (supine and prone) or in light (supine only). Background music was used to mask auditory orientation cues. Autonomic measurements included beat-to-beat recordings of blood pressure (Finapres), heart rate (ECG), cerebral blood flow velocity in the middle cerebral artery (transcranial Doppler), end tidal CO2, respiratory rate and volume (Respritrace), and stroke volume (impedance cardiography). For both patients and control subjects, cerebral blood flow appeared to exhibit the most rapid adjustment following transient changes in posture. Outside of a greater cerebral hypoperfusion in patients during the later stages of tilt, responses did not differ dramatically between the vestibular loss and control subjects, or between tilts performed in light and dark room conditions. Thus, with the 'exception of cerebrovascular regulation, we conclude that orthostatic responses during slow postural tilts are not substantially impaired in humans following chronic loss of vestibular function, a result that might reflect compensation by nonvisual graviceptor inputs (e.g., somatosensory) or other circulatory reflex mechanisms.

Quantifying kinematic differences between land and water during squats, split squats, and single-leg squats in a healthy population

PubMed Central

2017-01-01

Aquatic exercises can be used in clinical and sporting disciplines for both rehabilitation and sports training. However, there is limited knowledge on the influence of water immersion on the kinematics of exercises commonly used in rehabilitation and fitness programs. The aim of this study was to use inertial sensors to quantify differences in kinematics and movement variability of bodyweight squats, split squats, and single-leg squats performed on dry land and whilst immersed to the level of the greater trochanter. During two separate testing sessions, 25 active healthy university students (22.3±2.9 yr.) performed ten repetitions of each exercise, whilst tri-axial inertial sensors (100 Hz) recorded their trunk and lower body kinematics. Repeated-measures statistics tested for differences in segment orientation and speed, movement variability, and waveform patterns between environments, while coefficient of variance was used to assess differences in movement variability. Between-environment differences in segment orientation and speed were portrayed by plotting the mean difference ±95% confidence intervals (CI) throughout the tasks. The results showed that the depth of the squat and split squat were unaffected by the changed environment while water immersion allowed for a deeper single leg squat. The different environments had significant effects on the sagittal plane orientations and speeds for all segments. Water immersion increased the degree of movement variability of the segments in all exercises, except for the shank in the frontal plane, which showed more variability on land. Without compromising movement depth, the aquatic environment induces more upright trunk and shank postures during squats and split squats. The aquatic environment allows for increased squat depth during the single-leg squat, and increased shank motions in the frontal plane. Our observations therefore support the use of water-based squat tasks for rehabilitation as they appear to improve the technique without compromising movement depth. PMID:28767683

Up or down? Reading direction influences vertical counting direction in the horizontal plane - a cross-cultural comparison.

PubMed

Göbel, Silke M

2015-01-01

Most adults and children in cultures where reading text progresses from left to right also count objects from the left to the right side of space. The reverse is found in cultures with a right-to-left reading direction. The current set of experiments investigated whether vertical counting in the horizontal plane is also influenced by reading direction. Participants were either from a left-to-right reading culture (UK) or from a mixed (left-to-right and top-to-bottom) reading culture (Hong Kong). In Experiment 1, native English-speaking children and adults and native Cantonese-speaking children and adults performed three object counting tasks. Objects were presented flat on a table in a horizontal, vertical, and square display. Independent of culture, the horizontal array was mostly counted from left to right. While the majority of English-speaking children counted the vertical display from bottom to top, the majority of the Cantonese-speaking children as well as both Cantonese- and English-speaking adults counted the vertical display from top to bottom. This pattern was replicated in the counting pattern for squares: all groups except the English-speaking children started counting with the top left coin. In Experiment 2, Cantonese-speaking adults counted a square array of objects after they read a text presented to them either in left-to-right or in top-to-bottom reading direction. Most Cantonese-speaking adults started counting the array by moving horizontally from left to right. However, significantly more Cantonese-speaking adults started counting with a top-to-bottom movement after reading the text presented in a top-to-bottom reading direction than in a left-to-right reading direction. Our results show clearly that vertical counting in the horizontal plane is influenced by longstanding as well as more recent experience of reading direction.

The vast thin plane of M31 corotating dwarfs: an additional fossil signature of the M31 merger and of its considerable impact in the whole Local Group

NASA Astrophysics Data System (ADS)

Hammer, François; Yang, Yanbin; Fouquet, Sylvain; Pawlowski, Marcel S.; Kroupa, Pavel; Puech, Mathieu; Flores, Hector; Wang, Jianling

2013-06-01

The recent discovery by Ibata et al. of a vast thin disc of satellites (VTDS) around M31 offers a new challenge for the understanding of the Local Group properties. This comes in addition to the unexpected proximity of the Magellanic Clouds (MCs) to the Milky Way (MW), and to another vast polar structure (VPOS), which is almost perpendicular to our Galaxy disc. We find that the VTDS plane is coinciding with several stellar, tidally induced streams in the outskirts of M31, and, that its velocity distribution is consistent with that of the giant stream (GS). This is suggestive of a common physical mechanism, likely linked to merger tidal interactions, knowing that a similar argument may apply to the VPOS at the MW location. Furthermore, the VTDS is pointing towards the MW, being almost perpendicular to the MW disc, as the VPOS is. We compare these properties to the modelling of M31 as an ancient, gas-rich major merger, which has been successfully used to predict the M31 substructures and the GS origin. We find that without fine tuning, the induced tidal tails are lying in the VTDS plane, providing a single and common origin for many stellar streams and for the vast stellar structures surrounding both the MW and M31. The model also reproduces quite accurately positions and velocities of the VTDS spheroidal dwarfs. Our conjecture leads to a novel interpretation of the Local Group past history, as a gigantic tidal tail due to the M31 ancient merger is expected to send material towards the MW, including the MCs. Such a link between M31 and the MW is expected to be quite exceptional, though it may be in qualitative agreement with the reported rareness of MW-MCs systems in nearby galaxies.

A Robust Absorbing Boundary Condition for Compressible Flows

NASA Technical Reports Server (NTRS)

Loh, Ching Y.; orgenson, Philip C. E.

2005-01-01

An absorbing non-reflecting boundary condition (NRBC) for practical computations in fluid dynamics and aeroacoustics is presented with theoretical proof. This paper is a continuation and improvement of a previous paper by the author. The absorbing NRBC technique is based on a first principle of non reflecting, which contains the essential physics that a plane wave solution of the Euler equations remains intact across the boundary. The technique is theoretically shown to work for a large class of finite volume approaches. When combined with the hyperbolic conservation laws, the NRBC is simple, robust and truly multi-dimensional; no additional implementation is needed except the prescribed physical boundary conditions. Several numerical examples in multi-dimensional spaces using two different finite volume schemes are illustrated to demonstrate its robustness in practical computations. Limitations and remedies of the technique are also discussed.

Updated Panel-Method Computer Program

NASA Technical Reports Server (NTRS)

Ashby, Dale L.

1995-01-01

Panel code PMARC_12 (Panel Method Ames Research Center, version 12) computes potential-flow fields around complex three-dimensional bodies such as complete aircraft models. Contains several advanced features, including internal mathematical modeling of flow, time-stepping wake model for simulating either steady or unsteady motions, capability for Trefftz computation of drag induced by plane, and capability for computation of off-body and on-body streamlines, and capability of computation of boundary-layer parameters by use of two-dimensional integral boundary-layer method along surface streamlines. Investigators interested in visual representations of phenomena, may want to consider obtaining program GVS (ARC-13361), General visualization System. GVS is Silicon Graphics IRIS program created to support scientific-visualization needs of PMARC_12. GVS available separately from COSMIC. PMARC_12 written in standard FORTRAN 77, with exception of NAMELIST extension used for input.

Spherical visual system for real-time virtual reality and surveillance

NASA Astrophysics Data System (ADS)

Chen, Su-Shing

1998-12-01

A spherical visual system has been developed for full field, web-based surveillance, virtual reality, and roundtable video conference. The hardware is a CycloVision parabolic lens mounted on a video camera. The software was developed at the University of Missouri-Columbia. The mathematical model is developed by Su-Shing Chen and Michael Penna in the 1980s. The parabolic image, capturing the full (360 degrees) hemispherical field (except the north pole) of view is transformed into the spherical model of Chen and Penna. In the spherical model, images are invariant under the rotation group and are easily mapped to the image plane tangent to any point on the sphere. The projected image is exactly what the usual camera produces at that angle. Thus a real-time full spherical field video camera is developed by using two pieces of parabolic lenses.

The fingerprints of black holes—shadows and their degeneracies

NASA Astrophysics Data System (ADS)

Mars, Marc; Paganini, Claudio F.; Oancea, Marius A.

2018-01-01

We show that, away from the axis of symmetry, no continuous degeneration exists between the shadows of observers at any point in the exterior region of any Kerr–Newman black hole spacetime of unit mass. Therefore, except possibly for discrete changes, an observer can, by measuring the black holes shadow, determine the angular momentum and the charge of the black hole under observation as well as the observer’s radial position and angle of elevation above the equatorial plane. Furthermore, his/her relative velocity compared to a standard observer can also be measured. However, the black hole shadow does not allow for a full parameter resolution in the case of a Kerr–Newman–Taub–NUT black hole, as a continuous degeneration relating specific angular momentum, electric charge, Taub–NUT charge and elevation angle exists in this case.

The exceptional sediment load of fine-grained dispersal systems: Example of the Yellow River, China.

PubMed

Ma, Hongbo; Nittrouer, Jeffrey A; Naito, Kensuke; Fu, Xudong; Zhang, Yuanfeng; Moodie, Andrew J; Wang, Yuanjian; Wu, Baosheng; Parker, Gary

2017-05-01

Sedimentary dispersal systems with fine-grained beds are common, yet the physics of sediment movement within them remains poorly constrained. We analyze sediment transport data for the best-documented, fine-grained river worldwide, the Huanghe (Yellow River) of China, where sediment flux is underpredicted by an order of magnitude according to well-accepted sediment transport relations. Our theoretical framework, bolstered by field observations, demonstrates that the Huanghe tends toward upper-stage plane bed, yielding minimal form drag, thus markedly enhancing sediment transport efficiency. We present a sediment transport formulation applicable to all river systems with silt to coarse-sand beds. This formulation demonstrates a remarkably sensitive dependence on grain size within a certain narrow range and therefore has special relevance to silt-sand fluvial systems, particularly those affected by dams.

Universal RCFT correlators from the holomorphic bootstrap

NASA Astrophysics Data System (ADS)

Mukhi, Sunil; Muralidhara, Girish

2018-02-01

We elaborate and extend the method of Wronskian differential equations for conformal blocks to compute four-point correlation functions on the plane for classes of primary fields in rational (and possibly more general) conformal field theories. This approach leads to universal differential equations for families of CFT's and provides a very simple re-derivation of the BPZ results for the degenerate fields ϕ 1,2 and ϕ 2,1 in the c < 1 minimal models. We apply this technique to compute correlators for the WZW models corresponding to the Deligne-Cvitanović exceptional series of Lie algebras. The application turns out to be subtle in certain cases where there are multiple decoupled primaries. The power of this approach is demonstrated by applying it to compute four-point functions for the Baby Monster CFT, which does not belong to any minimal series.

HgCdTe APDS for time resolved space applications

NASA Astrophysics Data System (ADS)

Rothman, J.; Lasfargues, G.; Delacourt, B.; Dumas, A.; Gibert, F.; Bardoux, A.; Boutillier, M.

2017-09-01

HgCdTe APDs have opened a new horizon in photon starved applications due to their exceptional performance in terms of high linear gain, low excess noise and high quantum efficiency. Both focal plane arrays (FPAs) and large array single element using HgCdTe (MCT) APDs have been developed at CEA/Leti and Sofradir and high performance devices are at present available to detect without deterioration the spatial and/or temporal information in photon fluxes with a low number of photon in each spatio-temporal bin. The enhancement in performance that can be achieved with MCT has subsequently been demonstrated in a wide scope of applications such as astronomical observations, active imaging, deep space telecommunications, atmospheric LIDAR and mid-IR (MIR) time resolved photoluminescence measurements. Most of these applications can be used in space borne platforms.

A billion stars, a few million galaxies

NASA Astrophysics Data System (ADS)

Humphreys, Roberta M.; Thurmes, Peter M.

1994-05-01

The creation of an all-sky computerized astronomical catalog is discussed. The data source for the catalog was the first National Geographic Society-Palomar Observatory Sky Survey (POSS 1). Most of the plates produced in POSS 1 with the Oschin 48-inch Schmidt telescope were recently scanned by a team of astronomers using an automated plate scanner (APS) which is a high-speed laser scanner designed specifically to digitized information on astronomical photographs. To access the cataloged information easily, a specialized database program called StarBase was written. The expected size of the complete database (the catalog of objects plus the pixel data for the detected images) is 400 gigabytes. Scanning of 644 pairs of blue and red plates, covering the entire sky except for the crowded region within 20 deg of the galactic plane, has been completed. been completed.

The exceptional sediment load of fine-grained dispersal systems: Example of the Yellow River, China

PubMed Central

Ma, Hongbo; Nittrouer, Jeffrey A.; Naito, Kensuke; Fu, Xudong; Zhang, Yuanfeng; Moodie, Andrew J.; Wang, Yuanjian; Wu, Baosheng; Parker, Gary

2017-01-01

Sedimentary dispersal systems with fine-grained beds are common, yet the physics of sediment movement within them remains poorly constrained. We analyze sediment transport data for the best-documented, fine-grained river worldwide, the Huanghe (Yellow River) of China, where sediment flux is underpredicted by an order of magnitude according to well-accepted sediment transport relations. Our theoretical framework, bolstered by field observations, demonstrates that the Huanghe tends toward upper-stage plane bed, yielding minimal form drag, thus markedly enhancing sediment transport efficiency. We present a sediment transport formulation applicable to all river systems with silt to coarse-sand beds. This formulation demonstrates a remarkably sensitive dependence on grain size within a certain narrow range and therefore has special relevance to silt-sand fluvial systems, particularly those affected by dams. PMID:28508078

Aerodynamic characteristics of NACA RM-10 missile in 8- by 6-foot supersonic wind tunnel at Mach numbers from 1.49 to 1.98 I : presentation and analysis of pressure measurements (stabilizing fins removed)

NASA Technical Reports Server (NTRS)

Luidens, Roger W; Simon, Paul C

1950-01-01

Experimental investigation of flow about a slender body of revolution (NACA RM-10 missile) aligned and inclined to a supersonic stream was conducted at Mach numbers from 1.49 to 1.98 at a Reynolds number of approximately 30,000,000. Boundary-layer measurements at zero angle of attack are correlated with subsonic formulations for predicting boundary-layer thickness and profile. Comparison of pressure coefficients predicted by theory with experimental values showed close agreement at zero angle of attack and angle of attack except over the aft leeward side of body. At angle of attack, pitot pressure measurements in plane of model base indicated a pair of symmetrically disposed vortices on leeward side of body.

A contact binary asteroid evolutionary cycle driven by BYORP & the classical Laplace plane

NASA Astrophysics Data System (ADS)

Rieger, Samantha; Scheeres, Daniel J.

2017-10-01

Several contact binaries have been observed to have high obliquities distributed around 90°. With this information, we explore the possibility of these high obliquities being a key characteristic that causes an evolutionary cycle of contact binary formation and separation.The contact binary cycle begins with a single asteroid that is spinning up due to the YORP effect. For the binary cycle we assume YORP will drive the obliquity to 90°. Eventually, the asteroid will reach a critical spin frequency that will cause the asteroid to fission into a binary. We assume that the mass-ratio, q, of the system is greater than 0.2. With a high q, the secondary will not escape/impact the primary but will evolve through tides into a stable circular double-synchronous orbit. The binary being synchronous will cause the forces from BYORP to have secular effects on the system. For this cycle, BYORP will need to expand the secondary away from the primary.As the system expands, we have found that the secondary will follow the classical Laplace plane. Therefore, the secondary’s orbit will increase in inclination with respect to the equator as the secondary’s orbit expands. The Laplace plane is a stable orbit to perturbations from J2 & Sun tides except for an instability region that exists for primaries with obliquities above 68.875° & a secondary orbital radius of 13.5-19.5 primary radii. Once BYORP expands the secondary into this instability region, the eccentricity of the secondary’s orbit will increase until the orbit intersects with the primary & causes an impact. This impact will create a contact binary with a new obliquity that will randomly range from 23°-150°. The cycle will begin again with YORP driving the contact binary to an obliquity of 90°.Our contribution will discuss the proposed contact binary cycle in more detail, including the mechanics of the system that drives the events given above. We will include investigations into how losing synchronous lock will disrupt the eccentricity growth in the Laplace plane instability region. We will also discuss the time scales of each event to help predict which part of the cycle we will most likely to be observing when discovering new contact binaries & binary systems.

The use of artificial neural network for modeling the decolourization of acid orange 7 solution of industrial by ozonation process

NASA Astrophysics Data System (ADS)

Fatimah, S.; Wiharto, W.

2017-02-01

Acid Orange 7 (AO7) is one of the synthetic dye in the dyeing process in the textile industry. The use of this dye can produce wastewater which will be endangered if not treated well. Ozonation method is one technique to solve this problem. Ozonation is a waste processing techniques using ozone as an oxidizing agent. Variables used in this research is the ozone concentration, the initial concentration of AO7, temperature, and pH. Based on the experimental result that the optimum value decolourization percentage is 80% when the ozone concentration is 560 mg/L, the initial concentration AO7 is 14 mg/L, the temperature is 390 °C, and pH is 7,6. Decolourization efficiency of experimental results and predictions successfully modelled by the neural network architecture. The data used to construct a neural network architecture quasi newton one step secant as many as 31 data. A comparison between the predicted results of the designed ANN models and experiment was conducted. From the modeling results obtained MAPE value of 0.7763%. From the results of this artificial neural network architecture obtained the optimum value decolourization percentage in 80,64% when the concentration of ozone is 550 mg/L, the initial concentration AO7 is 11 mg/L, the temperature is 41 °C, and the pH is 7.9.

Combined effects of slip and convective boundary condition on MHD 3D stretched flow of nanofluid through porous media inspired by non-linear thermal radiation

NASA Astrophysics Data System (ADS)

Nayak, M. K.; Shaw, Sachin; Pandey, V. S.; Chamkha, Ali J.

2018-02-01

In the present study, the main concern is to investigate the magnetohydrodynamic nanofluid flow subject to porous matrix and convective heating past a permeable linear stretching sheet. In addition, the influence of velocity slip, viscous dissipation, Joule heating and non-linear thermal radiation are considered. A new micro-convection model known as the Patel model is implemented for considerable enhancement of the thermal conductivity and hence, the heat transfer capability of nanofluids. Moreover, a convective heat transfer model is introduced where the bottom surface of the sheet gets heated due to a convection mechanism from a hot fluid of particular temperature. The numerical results of the transformed governing differential equations have been obtained by using fourth-order Runge-Kutta method along with shooting approach and secant method is used for better approximation. In the present analysis, base fluids such as water and Ethylene glycol and Copper, Silver and Aluminum oxide nanoparticles are considered. Results of the present investigation show that inclusion of porous matrix contributes to slow down the fluid velocity and diminution of wall shear stress (axial as well as transverse). Drag force due to magnetic field strength, velocity slip and imposed fluid suction impede the fluid motion and upsurge the heat transfer rate from the surface. In addition, rise in viscous dissipation widens the thermal boundary layer.

Photometric Characterization of the Dark Energy Camera

DOE PAGES

Bernstein, G. M.; Abbott, T. M. C.; Armstrong, R.; ...

2018-04-02

We characterize the variation in photometric response of the Dark Energy Camera (DECam) across its 520 Mpix science array during 4 years of operation. These variations are measured using high signal-to-noise aperture photometry of >10 7 stellar images in thousands of exposures of a few selected fields, with the telescope dithered to move the sources around the array. A calibration procedure based on these results brings the rms variation in aperture magnitudes of bright stars on cloudless nights down to 2–3 mmag, with <1 mmag of correlated photometric errors for stars separated by ≥20''. On cloudless nights, any departures ofmore » the exposure zeropoints from a secant airmass law exceeding 1 mmag are plausibly attributable to spatial/temporal variations in aperture corrections. These variations can be inferred and corrected by measuring the fraction of stellar light in an annulus between 6'' and 8'' diameter. Key elements of this calibration include: correction of amplifier nonlinearities; distinguishing pixel-area variations and stray light from quantum-efficiency variations in the flat fields; field-dependent color corrections; and the use of an aperture-correction proxy. The DECam response pattern across the 2° field drifts over months by up to ±9 mmag, in a nearly wavelength-independent low-order pattern. Here, we find no fundamental barriers to pushing global photometric calibrations toward mmag accuracy.« less

Nonlocal Reformulations of Water and Internal Waves and Asymptotic Reductions

NASA Astrophysics Data System (ADS)

Ablowitz, Mark J.

2009-09-01

Nonlocal reformulations of the classical equations of water waves and two ideal fluids separated by a free interface, bounded above by either a rigid lid or a free surface, are obtained. The kinematic equations may be written in terms of integral equations with a free parameter. By expressing the pressure, or Bernoulli, equation in terms of the surface/interface variables, a closed system is obtained. An advantage of this formulation, referred to as the nonlocal spectral (NSP) formulation, is that the vertical component is eliminated, thus reducing the dimensionality and fixing the domain in which the equations are posed. The NSP equations and the Dirichlet-Neumann operators associated with the water wave or two-fluid equations can be related to each other and the Dirichlet-Neumann series can be obtained from the NSP equations. Important asymptotic reductions obtained from the two-fluid nonlocal system include the generalizations of the Benney-Luke and Kadomtsev-Petviashvili (KP) equations, referred to as intermediate-long wave (ILW) generalizations. These 2+1 dimensional equations possess lump type solutions. In the water wave problem high-order asymptotic series are obtained for two and three dimensional gravity-capillary solitary waves. In two dimensions, the first term in the asymptotic series is the well-known hyperbolic secant squared solution of the KdV equation; in three dimensions, the first term is the rational lump solution of the KP equation.

Astrometric Calibration and Performance of the Dark Energy Camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, G. M.; Armstrong, R.; Plazas, A. A.

2017-05-30

We characterize the variation in photometric response of the Dark Energy Camera (DECam) across its 520~Mpix science array during 4 years of operation. These variations are measured using high signal-to-noise aperture photometry ofmore » $>10^7$ stellar images in thousands of exposures of a few selected fields, with the telescope dithered to move the sources around the array. A calibration procedure based on these results brings the RMS variation in aperture magnitudes of bright stars on cloudless nights down to 2--3 mmag, with <1 mmag of correlated photometric errors for stars separated by $$\\ge20$$". On cloudless nights, any departures of the exposure zeropoints from a secant airmass law exceeding >1 mmag are plausibly attributable to spatial/temporal variations in aperture corrections. These variations can be inferred and corrected by measuring the fraction of stellar light in an annulus between 6" and 8" diameter. Key elements of this calibration include: correction of amplifier nonlinearities; distinguishing pixel-area variations and stray light from quantum-efficiency variations in the flat fields; field-dependent color corrections; and the use of an aperture-correction proxy. The DECam response pattern across the 2-degree field drifts over months by up to $$\\pm7$$ mmag, in a nearly-wavelength-independent low-order pattern. We find no fundamental barriers to pushing global photometric calibrations toward mmag accuracy.« less

Modified DFA and DCCA approach for quantifying the multiscale correlation structure of financial markets

NASA Astrophysics Data System (ADS)

Yin, Yi; Shang, Pengjian

2013-12-01

We use multiscale detrended fluctuation analysis (MSDFA) and multiscale detrended cross-correlation analysis (MSDCCA) to investigate auto-correlation (AC) and cross-correlation (CC) in the US and Chinese stock markets during 1997-2012. The results show that US and Chinese stock indices differ in terms of their multiscale AC structures. Stock indices in the same region also differ with regard to their multiscale AC structures. We analyze AC and CC behaviors among indices for the same region to determine similarity among six stock indices and divide them into four groups accordingly. We choose S&P500, NQCI, HSI, and the Shanghai Composite Index as representative samples for simplicity. MSDFA and MSDCCA results and average MSDFA spectra for local scaling exponents (LSEs) for individual series are presented. We find that the MSDCCA spectrum for LSE CC between two time series generally tends to be greater than the average MSDFA LSE spectrum for individual series. We obtain detailed multiscale structures and relations for CC between the four representatives. MSDFA and MSDCCA with secant rolling windows of different sizes are then applied to reanalyze the AC and CC. Vertical and horizontal comparisons of different window sizes are made. The MSDFA and MSDCCA results for the original window size are confirmed and some new interesting characteristics and conclusions regarding multiscale correlation structures are obtained.

Weighted finite impulse response filter for chromatic dispersion equalization in coherent optical fiber communication systems

NASA Astrophysics Data System (ADS)

Zeng, Ziyi; Yang, Aiying; Guo, Peng; Feng, Lihui

2018-01-01

Time-domain CD equalization using finite impulse response (FIR) filter is now a common approach for coherent optical fiber communication systems. The complex weights of FIR taps are calculated from a truncated impulse response of the CD transfer function, and the modulus of the complex weights is constant. In our work, we take the limited bandwidth of a single channel signal into account and propose weighted FIRs to improve the performance of CD equalization. The key in weighted FIR filters is the selection and optimization of weighted functions. In order to present the performance of different types of weighted FIR filters, a square-root raised cosine FIR (SRRC-FIR) and a Gaussian FIR (GS-FIR) are investigated. The optimization of square-root raised cosine FIR and Gaussian FIR are made in term of the bit rate error (BER) of QPSK and 16QAM coherent detection signal. The results demonstrate that the optimized parameters of the weighted filters are independent of the modulation format, symbol rate and the length of transmission fiber. With the optimized weighted FIRs, the BER of CD equalization signal is decreased significantly. Although this paper has investigated two types of weighted FIR filters, i.e. SRRC-FIR filter and GS-FIR filter, the principle of weighted FIR can also be extended to other symmetric functions super Gaussian function, hyperbolic secant function and etc.

Photometric Characterization of the Dark Energy Camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, G. M.; Abbott, T. M. C.; Armstrong, R.

We characterize the variation in photometric response of the Dark Energy Camera (DECam) across its 520 Mpix science array during 4 years of operation. These variations are measured using high signal-to-noise aperture photometry of >10 7 stellar images in thousands of exposures of a few selected fields, with the telescope dithered to move the sources around the array. A calibration procedure based on these results brings the rms variation in aperture magnitudes of bright stars on cloudless nights down to 2–3 mmag, with <1 mmag of correlated photometric errors for stars separated by ≥20''. On cloudless nights, any departures ofmore » the exposure zeropoints from a secant airmass law exceeding 1 mmag are plausibly attributable to spatial/temporal variations in aperture corrections. These variations can be inferred and corrected by measuring the fraction of stellar light in an annulus between 6'' and 8'' diameter. Key elements of this calibration include: correction of amplifier nonlinearities; distinguishing pixel-area variations and stray light from quantum-efficiency variations in the flat fields; field-dependent color corrections; and the use of an aperture-correction proxy. The DECam response pattern across the 2° field drifts over months by up to ±9 mmag, in a nearly wavelength-independent low-order pattern. Here, we find no fundamental barriers to pushing global photometric calibrations toward mmag accuracy.« less

Systematic design of 3D auxetic lattice materials with programmable Poisson's ratio for finite strains

NASA Astrophysics Data System (ADS)

Wang, Fengwen

2018-05-01

This paper presents a systematic approach for designing 3D auxetic lattice materials, which exhibit constant negative Poisson's ratios over large strain intervals. A unit cell model mimicking tensile tests is established and based on the proposed model, the secant Poisson's ratio is defined as the negative ratio between the lateral and the longitudinal engineering strains. The optimization problem for designing a material unit cell with a target Poisson's ratio is formulated to minimize the average lateral engineering stresses under the prescribed deformations. Numerical results demonstrate that 3D auxetic lattice materials with constant Poisson's ratios can be achieved by the proposed optimization formulation and that two sets of material architectures are obtained by imposing different symmetry on the unit cell. Moreover, inspired by the topology-optimized material architecture, a subsequent shape optimization is proposed by parametrizing material architectures using super-ellipsoids. By designing two geometrical parameters, simple optimized material microstructures with different target Poisson's ratios are obtained. By interpolating these two parameters as polynomial functions of Poisson's ratios, material architectures for any Poisson's ratio in the interval of ν ∈ [ - 0.78 , 0.00 ] are explicitly presented. Numerical evaluations show that interpolated auxetic lattice materials exhibit constant Poisson's ratios in the target strain interval of [0.00, 0.20] and that 3D auxetic lattice material architectures with programmable Poisson's ratio are achievable.

Estimating crustal heterogeneity from double-difference tomography

USGS Publications Warehouse

Got, J.-L.; Monteiller, V.; Virieux, J.; Okubo, P.

2006-01-01

Seismic velocity parameters in limited, but heterogeneous volumes can be inferred using a double-difference tomographic algorithm, but to obtain meaningful results accuracy must be maintained at every step of the computation. MONTEILLER et al. (2005) have devised a double-difference tomographic algorithm that takes full advantage of the accuracy of cross-spectral time-delays of large correlated event sets. This algorithm performs an accurate computation of theoretical travel-time delays in heterogeneous media and applies a suitable inversion scheme based on optimization theory. When applied to Kilauea Volcano, in Hawaii, the double-difference tomography approach shows significant and coherent changes to the velocity model in the well-resolved volumes beneath the Kilauea caldera and the upper east rift. In this paper, we first compare the results obtained using MONTEILLER et al.'s algorithm with those obtained using the classic travel-time tomographic approach. Then, we evaluated the effect of using data series of different accuracies, such as handpicked arrival-time differences ("picking differences"), on the results produced by double-difference tomographic algorithms. We show that picking differences have a non-Gaussian probability density function (pdf). Using a hyperbolic secant pdf instead of a Gaussian pdf allows improvement of the double-difference tomographic result when using picking difference data. We completed our study by investigating the use of spatially discontinuous time-delay data. ?? Birkha??user Verlag, Basel, 2006.

Photometric Characterization of the Dark Energy Camera

NASA Astrophysics Data System (ADS)

Bernstein, G. M.; Abbott, T. M. C.; Armstrong, R.; Burke, D. L.; Diehl, H. T.; Gruendl, R. A.; Johnson, M. D.; Li, T. S.; Rykoff, E. S.; Walker, A. R.; Wester, W.; Yanny, B.

2018-05-01

We characterize the variation in photometric response of the Dark Energy Camera (DECam) across its 520 Mpix science array during 4 years of operation. These variations are measured using high signal-to-noise aperture photometry of >107 stellar images in thousands of exposures of a few selected fields, with the telescope dithered to move the sources around the array. A calibration procedure based on these results brings the rms variation in aperture magnitudes of bright stars on cloudless nights down to 2–3 mmag, with <1 mmag of correlated photometric errors for stars separated by ≥20″. On cloudless nights, any departures of the exposure zeropoints from a secant airmass law exceeding 1 mmag are plausibly attributable to spatial/temporal variations in aperture corrections. These variations can be inferred and corrected by measuring the fraction of stellar light in an annulus between 6″ and 8″ diameter. Key elements of this calibration include: correction of amplifier nonlinearities; distinguishing pixel-area variations and stray light from quantum-efficiency variations in the flat fields; field-dependent color corrections; and the use of an aperture-correction proxy. The DECam response pattern across the 2° field drifts over months by up to ±9 mmag, in a nearly wavelength-independent low-order pattern. We find no fundamental barriers to pushing global photometric calibrations toward mmag accuracy.

Spall response of single-crystal copper

NASA Astrophysics Data System (ADS)

Turley, W. D.; Fensin, S. J.; Hixson, R. S.; Jones, D. R.; La Lone, B. M.; Stevens, G. D.; Thomas, S. A.; Veeser, L. R.

2018-02-01

We performed a series of systematic spall experiments on single-crystal copper in an effort to determine and isolate the effects of crystal orientation, peak stress, and unloading strain rate on the tensile spall strength. Strain rates ranging from 0.62 to 2.2 × 106 s-1 and peak shock stresses in the 5-14 GPa range, with one additional experiment near 50 GPa, were explored as part of this work. Gun-driven impactors, called flyer plates, generated flat top shocks followed by spall. This work highlights the effect of crystal anisotropy on the spall strength by showing that the spall strength decreases in the following order: [100], [110], and [111]. Over the range of stresses and strain rates explored, the spall strength of [100] copper depends strongly on both the strain rate and shock stress. Except at the very highest shock stress, the results for the [100] orientation show linear relationships between the spall strength and both the applied compressive stress and the strain rate. In addition, hydrodynamic computer code simulations of the spall experiments were performed to calculate the relationship between the strain rate near the spall plane in the target and the rate of free surface velocity release during the pullback. As expected, strain rates at the spall plane are much higher than the strain rates estimated from the free surface velocity release rate. We have begun soft recovery experiments and molecular dynamics calculations to understand the unusual recompression observed in the spall signature for [100] crystals.

Calibration of the ART-XC mirror modules at MSFC

NASA Astrophysics Data System (ADS)

Krivonos, R.; Tkachenko, A.; Burenin, R.; Filippova, E.; Lapshov, I.; Mereminskiy, I.; Molkov, S.; Pavlinsky, M.; Sazonov, S.; Gubarev, M.; Kolodziejczak, J.; O'Dell, S. L.; Swartz, D.; Zavlin, Vyacheslav E.; Ramsey, B. D.

2017-10-01

The Astronomical Röntgen Telescope X-ray Concentrator (ART-XC) is a hard X-ray telescope with energy response up to 30 keV, to be launched on board the Spectrum Röntgen Gamma (SRG) spacecraft in 2018. ART-XC consists of seven identical co-aligned mirror modules. Each mirror assembly is coupled with a CdTe double-sided strip (DSS) focal-plane detector. Eight X-ray mirror modules (seven flight and one spare units) for ART-XC were developed and fabricated at the Marshall Space Flight Center (MSFC), NASA, USA. We present results of testing procedures performed with an X-ray beam facility at MSFC to calibrate the point spread function (PSF) of the mirror modules. The shape of the PSF was measured with a high-resolution CCD camera installed in the focal plane with defocusing of 7 mm, as required by the ART-XC design. For each module, we performed a parametrization of the PSF at various angular distances Θ. We used a King function to approximate the radial profile of the near on-axis PSF (Θ < 9 arcmin) and an ellipse fitting procedure to describe the morphology of the far off-axis angular response (9 < Θ < 24 arcmin). We found a good agreement between the seven ART-XC flight mirror modules at the level of 10%. The on-axis angular resolution of the ART-XC optics varies between 27 and 33 arcsec (half-power diameter), except for the spare module.

[Determination of absorbed dose to water for high energy photon and electron beams--comparison of different dosimetry protocols].

PubMed

Zakaria, Golam Abu; Schütte, Wilhelm

2003-01-01

The determination of absorbed dose to water for high-energy photon and electron beams is performed in Germany according to the dosimetry protocol DIN 6800-2 (1997). At an international level, the main protocols used are the AAPM dosimetry protocol TG-51 (1999) and the IAEA Code of Practice TRS-398 (2000). The present paper systematically compares these three dosimetry protocols, and identifies similarities and differences. The investigations were performed using 4 and 10 MV photon beams, as well as 6, 8, 9, 10, 12 and 14 MeV electron beams. Two cylindrical and two plane-parallel type chambers were used for measurements. In general, the discrepancies among the three protocols were 1.0% for photon beams and 1.6% for electron beams. Comparative measurements in the context of measurement technical control (MTK) with TLD showed a deviation of less than 1.3% between the measurements obtained according to protocols DIN 6800-2 and MTK (exceptions: 4 MV photons with 2.9% and 6 MeV electrons with 2.4%). While only cylindrical chambers were used for photon beams, measurements of electron beams were performed using both cylindrical and plane-parallel chambers (the latter used after a cross-calibration to a cylindrical chamber, as required by the respective dosimetry protocols). Notably, unlike recommended in the corresponding protocols, we found out that cylindrical chambers can be used also for energies from 6 to 10 MeV.

Quality control in interstitial brachytherapy of the breast using pulsed dose rate: treatment planning and dose delivery with an Ir-192 afterloading system.

PubMed

Mangold, C A; Rijnders, A; Georg, D; Van Limbergen, E; Pötter, R; Huyskens, D

2001-01-01

In the Radiotherapy Department of Leuven, about 20% of all breast cancer patients treated with breast conserving surgery and external radiotherapy receive an additional boost with pulsed dose rate (PDR) Ir-192 brachytherapy. An investigation was performed to assess the accuracy of the delivered PDR brachytherapy treatment. Secondly, the feasibility of in vivo measurements during PDR dose delivery was investigated. Two phantoms are manufactured to mimic a breast, one for thermoluminescent dosimetry (TLD) measurements, and one for dosimetry using radiochromic films. The TLD phantom allows measurements at 34 dose points in three planes including the basal dose points. The film phantom is designed in such a way that films can be positioned in a plane parallel and orthogonal to the needles. The dose distributions calculated with the TPS are in good agreement with both TLD and radiochromic film measurements (average deviations of point doses <+/-5%). However, close to the interface tissue-air the dose is overestimated by the TPS since it neglects the finite size of a breast and the associated lack of backscatter (average deviations of point doses -14%). Most deviations between measured and calculated doses, are in the order of magnitude of the uncertainty associated with the source strength specification, except for the point doses measured close to the skin. In vivo dosimetry during PDR brachytherapy treatment was found to be a valuable procedure to detect large errors, e.g. errors caused by an incorrect data transfer.

Centralspindlin and Chromosomal Passenger Complex Behavior During Normal and Rappaport Furrow Specification in Echinoderm Embryos

PubMed Central

Argiros, Haroula; Henson, Lauren; Holguin, Christiana; Foe, Victoria; Shuster, Charles Bradley

2014-01-01

The chromosomal passenger (CPC) and Centralspindlin complexes are essential for organizing the anaphase central spindle and providing cues that position the cytokinetic furrow between daughter nuclei. However, echinoderm zygotes are also capable of forming “Rappaport furrows” between asters positioned back-to-back without intervening chromosomes. To understand how these complexes contribute to normal and Rappaport furrow formation, we studied the localization patterns of Survivin and mitotic-kinesin-like-protein1 (MKLP1), members respectively of the CPC and the Centralspindlin complex, and the effect of CPC inhibition on cleavage in mono- and binucleate echinoderm zygotes. In zygotes, Survivin initially localized to metaphase chromosomes, upon anaphase onset relocalized to the central spindle and then, together with MKLP1 spread towards the equatorial cortex in an Aurora-dependent manner. Inhibition of Aurora kinase activity resulted in disruption of central spindle organization and furrow regression, although astral microtubule elongation and furrow initiation were normal. In binucleate cells containing two parallel spindles MKLP1 and Survivin localized to the plane of the former metaphase plate, but were not observed in the secondary cleavage plane formed between unrelated spindle poles, except when chromosomes were abnormally present there. However, the secondary furrow was sensitive to Aurora inhibition, indicating that Aurora kinase may still contribute to furrow ingression without chromosomes nearby. Our results provide insights that reconcile classic micromanipulation studies with current molecular understanding of furrow specification in animal cells. PMID:22887753

Relationship between vertical facial patterns and dental arch form in class II malocclusion.

PubMed

Grippaudo, Cristina; Oliva, Bruno; Greco, Anna Lucia; Sferra, Simone; Deli, Roberto

2013-11-07

The purpose of this study is to evaluate the relationship between dental arch form and the vertical facial pattern determined by the angle between the mandibular plane and the anterior cranial base (Sella-nasion/mandibular plane angle (SN-MP)) in skeletal class II untreated patients. A sample of 73 Caucasians patients with untreated skeletal class II in permanent dentition was divided into three groups according to the values of the angle SN-MP. An evaluation of the arch form was performed by angular and linear relation values on each patient. Regression analysis was used to determine the statistical significance of the relationships between SN-MP angle and dental arch form. The differences among the three groups were analyzed for significance using a variance analysis. A decrease of the upper arch transversal diameters in high SN-MP angle patients and an increase in low angle SN-MP ones (P<0.05) were shown. Result analysis showed a change in upper arch shape, with a smaller intercanine width in patients with high SN-MP angle and a greater one in low angle patients. As SN-MP angle increased, the upper arch form tended to be narrower. No statistically significant difference in mandibular arch form among the three groups was found, except the angle value related to incisors position. The results showed the association between the upper dental arch form and the vertical facial pattern. On the contrary, the lower arch form was not related to the mandibular divergence.

Biosonar navigation above water I: estimating flight height.

PubMed

Hoffmann, Susanne; Genzel, Daria; Prosch, Selina; Baier, Leonie; Weser, Sabrina; Wiegrebe, Lutz; Firzlaff, Uwe

2015-02-15

Locomotion and foraging on the wing require precise navigation in more than just the horizontal plane. Navigation in three dimensions and, specifically, precise adjustment of flight height are essential for flying animals. Echolocating bats drink from water surfaces in flight, which requires an exceptionally precise vertical navigation. Here, we exploit this behavior in the bat, Phyllostomus discolor, to understand the biophysical and neural mechanisms that allow for sonar-guided navigation in the vertical plane. In a set of behavioral experiments, we show that for echolocating bats, adjustment of flight height depends on the tragus in their outer ears. Specifically, the tragus imposes elevation-specific spectral interference patterns on the echoes of the bats' sonar emissions. Head-related transfer functions of our bats show that these interference patterns are most conspicuous in the frequency range ∼55 kHz. This conspicuousness is faithfully preserved in the frequency tuning and spatial receptive fields of cortical single and multiunits recorded from anesthetized animals. In addition, we recorded vertical spatiotemporal response maps that describe neural tuning in elevation over time. One class of units that were very sharply tuned to frequencies ∼55 kHz showed unusual spatiotemporal response characteristics with a preference for paired echoes where especially the first echo originates from very low elevations. These behavioral and neural data provide the first insight into biosonar-based processing and perception of acoustic elevation cues that are essential for bats to navigate in three-dimensional space. Copyright © 2015 the American Physiological Society.

Phonon thermal transport in 2H, 4H and 6H silicon carbide from first principles

DOE PAGES

Protik, Nakib Haider; Katre, Ankita; Lindsay, Lucas R.; ...

2017-06-07

Here, silicon carbide (SiC) is a wide band gap semiconductor with a variety of industrial applications. Among its many useful properties is its high thermal conductivity, which makes it advantageous for thermal management applications. In this paper we present ab initio calculations of the in-plane and cross-plane thermal conductivities, κ in and κ out, of three common hexagonal polytypes of SiC: 2H, 4H and 6H. The phonon Boltzmann transport equation is solved iteratively using as input interatomic force constants determined from density functional theory. Both κ in and κ out decrease with increasing n in nH SiC because of additionalmore » low-lying optic phonon branches. These optic branches are characterized by low phonon group velocities, and they increase the phase space for phonon-phonon scattering of acoustic modes. Also, for all n, κ in is found to be larger than κ out in the temperature range considered. At electron concentrations present in experimental samples, scattering of phonons by electrons is shown to be negligible except well below room temperature where it can lead to a significant reduction of the lattice thermal conductivity. This work highlights the power of ab initio approaches in giving quantitative, predictive descriptions of thermal transport in materials. It helps explain the qualitative disagreement that exists among different sets of measured thermal conductivity data and provides information of the relative quality of samples from which measured data was obtained.« less

Revision of the Li13Si4 structure

PubMed Central

Zeilinger, Michael; Fässler, Thomas F.

2013-01-01

Besides Li17Si4, Li16.42Si4, and Li15Si4, another lithium-rich representative in the Li–Si system is the phase Li13Si4 (trideca­lithium tetra­silicide), the structure of which has been determined previously [Frank et al. (1975 ▶). Z. Naturforsch. Teil B, 30, 10–13]. A careful analysis of X-ray diffraction patterns of Li13Si4 revealed discrepancies between experimentally observed and calculated Bragg positions. Therefore, we redetermined the structure of Li13Si4 on the basis of single-crystal X-ray diffraction data. Compared to the previous structure report, decisive differences are (i) the introduction of a split position for one Li site [occupancy ratio 0.838 (7):0.162 (7)], (ii) the anisotropic refinement of atomic displacement parameters for all atoms, and (iii) a high accuracy of atom positions and unit-cell parameters. The asymmetric unit of Li13Si4 contains two Si and seven Li atoms. Except for one Li atom situated on a site with symmetry 2/m, all other atoms are on mirror planes. The structure consists of isolated Si atoms as well as Si–Si dumbbells surrounded by Li atoms. Each Si atom is either 12- or 13-coordinated. The isolated Si atoms are situated in the ab plane at z = 0 and are strictly separated from the Si–Si dumbbells at z = 0.5. PMID:24454148

Topographic Effects on the Surface Emissivity of a Mountainous Area Observed by a Spaceborne Microwave Radiometer

PubMed Central

Pulvirenti, Luca; Pierdicca, Nazzareno; Marzano, Frank S.

2008-01-01

A simulation study to understand the influence of topography on the surface emissivity observed by a satellite microwave radiometer is carried out. We analyze the effects due to changes in observation angle, including the rotation of the polarization plane. A mountainous area in the Alps (Northern Italy) is considered and the information on the relief extracted from a digital elevation model is exploited. The numerical simulation refers to a radiometric image, acquired by a conically-scanning radiometer similar to AMSR-E, i.e., flying at 705 km of altitude with an observation angle of 55°. To single out the impact on surface emissivity, scattering of the radiation due to the atmosphere or neighboring elevated surfaces is not considered. C and X bands, for which atmospheric effects are negligible, and Ka band are analyzed. The results indicate that the changes in the local observation angle tend to lower the apparent emissivity of a radiometric pixel with respect to the corresponding flat surface characteristics. The effect of the rotation of the polarization plane enlarges (vertical polarization), or attenuates (horizontal polarization) this decrease. By doing some simplifying assumptions for the radiometer antenna, the conclusion is that the microwave emissivity at vertical polarization is underestimated, whilst the opposite occurs for horizontal polarization, except for Ka band, for which both under- and overprediction may occur. A quantification of the differences with respect to a flat soil and an approximate evaluation of their impact on soil moisture retrieval are yielded. PMID:27879773

SIMULTANEOUS LINEAR AND CIRCULAR OPTICAL POLARIMETRY OF ASTEROID (4) VESTA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiktorowicz, Sloane J.; Nofi, Larissa A., E-mail: sloanew@ucolick.org

From a single 3.8 hr observation of the asteroid (4) Vesta at 13.°7 phase angle with the POlarimeter at Lick for Inclination Studies of Hot jupiters 2 (POLISH2) at the Lick Observatory Shane 3 m telescope, we confirm rotational modulation of linear polarization in the B and V bands. We measure the peak-to-peak modulation in the degree of linear polarization to be ΔP = (294 ± 35) × 10{sup −6} (ppm) and time-averaged ΔP/P = 0.0575 ± 0.0069. After rotating the plane of linear polarization to the scattering plane, asteroidal rotational modulation is detected with 12σ confidence and observed solelymore » in Stokes Q/I. POLISH2 simultaneously measures Stokes I, Q, U (linear polarization), and V (circular polarization), but we detect no significant circular polarization with a 1σ upper limit of 78 ppm in the B band. Circular polarization is expected to arise from multiple scattering of sunlight by rough surfaces, and it has previously been detected in nearly all other classes of solar system bodies except for asteroids. Subsequent observations may be compared with surface albedo maps from the Dawn Mission, which may allow the identification of compositional variation across the asteroidal surface. These results demonstrate the high accuracy achieved by POLISH2 at the Lick 3 m telescope, which is designed to directly detect scattered light from spatially unresolvable exoplanets.« less

Phonon thermal transport in 2H, 4H and 6H silicon carbide from first principles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Protik, Nakib Haider; Katre, Ankita; Lindsay, Lucas R.

Here, silicon carbide (SiC) is a wide band gap semiconductor with a variety of industrial applications. Among its many useful properties is its high thermal conductivity, which makes it advantageous for thermal management applications. In this paper we present ab initio calculations of the in-plane and cross-plane thermal conductivities, κ in and κ out, of three common hexagonal polytypes of SiC: 2H, 4H and 6H. The phonon Boltzmann transport equation is solved iteratively using as input interatomic force constants determined from density functional theory. Both κ in and κ out decrease with increasing n in nH SiC because of additionalmore » low-lying optic phonon branches. These optic branches are characterized by low phonon group velocities, and they increase the phase space for phonon-phonon scattering of acoustic modes. Also, for all n, κ in is found to be larger than κ out in the temperature range considered. At electron concentrations present in experimental samples, scattering of phonons by electrons is shown to be negligible except well below room temperature where it can lead to a significant reduction of the lattice thermal conductivity. This work highlights the power of ab initio approaches in giving quantitative, predictive descriptions of thermal transport in materials. It helps explain the qualitative disagreement that exists among different sets of measured thermal conductivity data and provides information of the relative quality of samples from which measured data was obtained.« less

Investigation of sparsity metrics for autofocusing in digital holographic microscopy

NASA Astrophysics Data System (ADS)

Fan, Xin; Healy, John J.; Hennelly, Bryan M.

2017-05-01

Digital holographic microscopy (DHM) is an optoelectronic technique that is made up of two parts: (i) the recording of the interference pattern of the diffraction pattern of an object and a known reference wavefield using a digital camera and (ii) the numerical reconstruction of the complex object wavefield using the recorded interferogram and a distance parameter as input. The latter is based on the simulation of optical propagation from the camera plane to a plane at any arbitrary distance from the camera. A key advantage of DHM over conventional microscopy is that both the phase and intensity information of the object can be recovered at any distance, using only one capture, and this facilitates the recording of scenes that may change dynamically and that may otherwise go in and out of focus. Autofocusing using traditional microscopy requires mechanical movement of the translation stage or the microscope objective, and multiple image captures that are then compared using some metric. Autofocusing in DHM is similar, except that the sequence of intensity images, to which the metric is applied, is generated numerically from a single capture. We recently investigated the application of a number of sparsity metrics for DHM autofocusing and in this paper we extend this work to include more such metrics, and apply them over a greater range of biological diatom cells and magnification/numerical apertures. We demonstrate for the first time that these metrics may be grouped together according to matching behavior following high pass filtering.

Coordination Structure and Fragmentation Chemistry of the Tripositive Lanthanide-Thio-Diglycolamide Complexes.

PubMed

Chen, Xiuting; Li, Qingnuan; Gong, Yu

2017-12-14

Tripositive Ln(TMTDA) 3 3+ complexes (Ln = La-Lu except Pm, TMTDA = tetramethyl 3-thio-diglycolamide) were observed in the gas phase by electrospray ionization of LnCl 3 and TMTDA mixtures. Collision-induced dissociation (CID) was employed to investigate their fragmentation chemistry, which revealed the influence of metal center as well as ligand on the ligated complexes. Ln(TMTDA) 2 (TMTDA-45) 3+ resulting from C carbonyl -N bond cleavage of TMTDA and hydrogen transfer was the major CID product for all Ln(TMTDA) 3 3+ except Eu(TMTDA) 3 3+ , which predominantly formed charge-reducing product Eu II (TMTDA) 2 2+ via electron transfer from TMTDA to Eu 3+ . Density functional theory calculations on the structure of La(TMTDA) 3 3+ and Lu(TMTDA) 3 3+ revealed that Ln 3+ was coordinated by six O carbonyl atoms from three neutral TMTDA ligands, and both complexes possessed C 3h symmetry. The S ether atom deviating from the ligand plane was not coordinated to the metal center. On the basis of the CID results of Ln(TMTDA) 3 3+ , Ln(TMGA) 3 3+ , and Ln(TMOGA) 3 3+ , the fragmentation chemistry associated with the ligand depends on the coordination mode, while the redox chemistry of these tripositive ions is related to the nature of both metal centers and diamide ligands.

On a class of Newton-like methods for solving nonlinear equations

NASA Astrophysics Data System (ADS)

Argyros, Ioannis K.

2009-06-01

We provide a semilocal convergence analysis for a certain class of Newton-like methods considered also in [I.K. Argyros, A unifying local-semilocal convergence analysis and applications for two-point Newton-like methods in Banach space, J. Math. Anal. Appl. 298 (2004) 374-397; I.K. Argyros, Computational theory of iterative methods, in: C.K. Chui, L. Wuytack (Eds.), Series: Studies in Computational Mathematics, vol. 15, Elsevier Publ. Co, New York, USA, 2007; J.E. Dennis, Toward a unified convergence theory for Newton-like methods, in: L.B. Rall (Ed.), Nonlinear Functional Analysis and Applications, Academic Press, New York, 1971], in order to approximate a locally unique solution of an equation in a Banach space. Using a combination of Lipschitz and center-Lipschitz conditions, instead of only Lipschitz conditions [F.A. Potra, Sharp error bounds for a class of Newton-like methods, Libertas Math. 5 (1985) 71-84], we provide an analysis with the following advantages over the work in [F.A. Potra, Sharp error bounds for a class of Newton-like methods, Libertas Math. 5 (1985) 71-84] which improved the works in [W.E. Bosarge, P.L. Falb, A multipoint method of third order, J. Optimiz. Theory Appl. 4 (1969) 156-166; W.E. Bosarge, P.L. Falb, Infinite dimensional multipoint methods and the solution of two point boundary value problems, Numer. Math. 14 (1970) 264-286; J.E. Dennis, On the Kantorovich hypothesis for Newton's method, SIAM J. Numer. Anal. 6 (3) (1969) 493-507; J.E. Dennis, Toward a unified convergence theory for Newton-like methods, in: L.B. Rall (Ed.), Nonlinear Functional Analysis and Applications, Academic Press, New York, 1971; H.J. Kornstaedt, Ein allgemeiner Konvergenzstaz fü r verschä rfte Newton-Verfahrem, in: ISNM, vol. 28, Birkhaü ser Verlag, Basel and Stuttgart, 1975, pp. 53-69; P. Laasonen, Ein überquadratisch konvergenter iterativer algorithmus, Ann. Acad. Sci. Fenn. Ser I 450 (1969) 1-10; F.A. Potra, On a modified secant method, L'analyse numérique et la theorie de l'approximation 8 (2) (1979) 203-214; F.A. Potra, An application of the induction method of V. Pták to the study of Regula Falsi, Aplikace Matematiky 26 (1981) 111-120; F.A. Potra, On the convergence of a class of Newton-like methods, in: Iterative Solution of Nonlinear Systems of Equations, in: Lecture Notes in Mathematics, vol. 953, Springer-Verlag, New York, 1982; F.A. Potra, V. Pták, Nondiscrete induction and double step secant method, Math. Scand. 46 (1980) 236-250; F.A. Potra, V. Pták, On a class of modified Newton processes, Numer. Funct. Anal. Optim. 2 (1) (1980) 107-120; F.A. Potra, Sharp error bounds for a class of Newton-like methods, Libertas Math. 5 (1985) 71-84; J.W. Schmidt, Untere Fehlerschranken für Regula-Falsi Verfahren, Period. Math. Hungar. 9 (3) (1978) 241-247; J.W. Schmidt, H. Schwetlick, Ableitungsfreie Verfhren mit höherer Konvergenzgeschwindifkeit, Computing 3 (1968) 215-226; J.F. Traub, Iterative Methods for the Solution of Equations, Prentice Hall, Englewood Cliffs, New Jersey, 1964; M.A. Wolfe, Extended iterative methods for the solution of operator equations, Numer. Math. 31 (1978) 153-174]: larger convergence domain and weaker sufficient convergence conditions. Numerical examples further validating the results are also provided.

Hypercalculia in savant syndrome: central executive failure?

PubMed

González-Garrido, Andrés Antonio; Ruiz-Sandoval, José Luis; Gómez-Velázquez, Fabiola R; de Alba, José Luis Oropeza; Villaseñor-Cabrera, Teresa

2002-01-01

The existence of outstanding cognitive talent in mentally retarded subjects persists as a challenge to present knowledge. We report the case of a 16-year-old male patient with exceptional mental calculation abilities and moderate mental retardation. The patient was clinically evaluated. Data from standard magnetic resonance imaging (MRI) and two 99mTc-ethyl cysteine dimer (ECD)-single photon emission computer tomography (SPECT) (in resting condition and performing a mental calculation task) studies were analyzed. Main neurologic findings were brachycephalia, right-side neurologic soft signs, obsessive personality profile, low color-word interference effect in Stroop test, and diffuse increased cerebral blood flow during calculation task in 99mTc-ECD SPECT. MRI showed anatomical temporal plane inverse asymmetry. Evidence appears to support the hypothesis that savant skill is related to excessive and erroneous use of cognitive processing resources instigated by probable failure in central executive control mechanisms.

Ab-initio calculation of electronic structure and optical properties of AB-stacked bilayer α-graphyne

NASA Astrophysics Data System (ADS)

Behzad, Somayeh

2016-09-01

Monolayer α-graphyne is a new two-dimensional carbon allotrope with many special features. In this work the electronic properties of AA- and AB-stacked bilayers of this material and then the optical properties are studied, using first principle plane wave method. The electronic spectrum has two Dirac cones for AA stacked bilayer α-graphyne. For AB-stacked bilayer, the interlayer interaction changes the linear bands into parabolic bands. The optical spectra of the most stable AB-stacked bilayer closely resemble to that of the monolayer, except for small shifts of peak positions and increasing of their intensity. For AB-stacked bilayer, a pronounced peak has been found at low energies under the perpendicular polarization. This peak can be clearly ascribed to the transitions at the Dirac point as a result of the small degeneracy lift in the band structure.

Graphical method to design multilayer phase retarders.

PubMed

Apfel, J H

1981-03-15

When multilayer reflectors are used at nonnormal incidence, the two planes of polarization generally have different phase shifts. This difference, known as phase retardance, depends on the multilayer design, the incidence angle, and the wavelength. Heretofore, the design of reflectors with specific phase retardance has been carried out by computer optimization except for the case of a single layer on a metal substrate. A graph of phase retardance D vs the average phase shift A as a function of layer thickness provides a means for visualization that is useful in reflector designs. A D-A graph predicts the phase properties of a reflector as a function of the index and thickness of an added layer. Graphs of phase retardance vs average phase for two different materials can be superposed to predict the composite performance of a multilayer reflector. This graphical technique is employed to design and analyze reflectors with specified phase retardance.

Investigation at transonic speeds of the lateral-control and hinge-moment characteristics of a flap-type spoiler aileron on a 60 degree delta wing

NASA Technical Reports Server (NTRS)

Wiley, Harleth G; Taylor, Robert T

1954-01-01

This paper present results of an investigation of the lateral-control and hinge-moment characteristics of a 0.67 semispan flap-type spoiler aileron on a semispan thin 60 degree delta wing at transonic speeds by the reflection-plane technique. The spoiler-aileron had a constant chord of 10.29 percent mean aerodynamic chord and was hinged at the 81.9-percent-wing-root-chord station. Tests were made with the spoiler aileron slot open, partially closed, and closed. Incremental rolling-moment coefficients were obtained through a Mach number range of 0.62 to 1.08. Results indicated reasonably linear variations of rolling-moment and hinge-moment coefficients with spoiler projection except at spoiler projections of less than -2 percent mean aerodynamic chord and angles of attack greater than 12 degrees with results generally independent of slot geometry.

Precise through-space control of an abiotic electrophilic aromatic substitution reaction

NASA Astrophysics Data System (ADS)

Murphy, Kyle E.; Bocanegra, Jessica L.; Liu, Xiaoxi; Chau, H.-Y. Katharine; Lee, Patrick C.; Li, Jianing; Schneebeli, Severin T.

2017-04-01

Nature has evolved selective enzymes for the efficient biosynthesis of complex products. This exceptional ability stems from adapted enzymatic pockets, which geometrically constrain reactants and stabilize specific reactive intermediates by placing electron-donating/accepting residues nearby. Here we perform an abiotic electrophilic aromatic substitution reaction, which is directed precisely through space. Ester arms--positioned above the planes of aromatic rings--enable it to distinguish between nearly identical, neighbouring reactive positions. Quantum mechanical calculations show that, in two competing reaction pathways, both [C-H...O]-hydrogen bonding and electrophile preorganization by coordination to a carbonyl group likely play a role in controlling the reaction. These through-space-directed mechanisms are inspired by dimethylallyl tryptophan synthases, which direct biological electrophilic aromatic substitutions by preorganizing dimethylallyl cations and by stabilizing reactive intermediates with [C-H...N]-hydrogen bonding. Our results demonstrate how the third dimension above and underneath aromatic rings can be exploited to precisely control electrophilic aromatic substitutions.

Dynamical Evolution of an Effective Two-Level System with {\\mathscr{P}}{\\mathscr{T}} Symmetry

NASA Astrophysics Data System (ADS)

Du, Lei; Xu, Zhihao; Yin, Chuanhao; Guo, Liping

2018-05-01

We investigate the dynamics of parity- and time-reversal (PT ) symmetric two-energy-level atoms in the presence of two optical and a radio-frequency (rf) fields. The strength and relative phase of fields can drive the system from unbroken to broken PT symmetric regions. Compared with the Hermitian model, Rabi-type oscillation is still observed, and the oscillation characteristics are also adjusted by the strength and relative phase in the region of unbroken PT symmetry. At exception point (EP), the oscillation breaks down. To better understand the underlying properties we study the effective Bloch dynamics and find the emergence of the z components of the fixed points is the feature of the PT symmetry breaking and the projections in x-y plane can be controlled with high flexibility compared with the standard two-level system with PT symmetry. It helps to study the dynamic behavior of the complex PT symmetric model.

Tomographic techniques for the study of exceptionally preserved fossils

PubMed Central

Sutton, Mark D

2008-01-01

Three-dimensional fossils, especially those preserving soft-part anatomy, are a rich source of palaeontological information; they can, however, be difficult to work with. Imaging of serial planes through an object (tomography) allows study of both the inside and outside of three-dimensional fossils. Tomography may be performed using physical grinding or sawing coupled with photography, through optical techniques of serial focusing, or using a variety of scanning technologies such as neutron tomography, magnetic resonance imaging and most usefully X-ray computed tomography. This latter technique is applicable at a variety of scales, and when combined with a synchrotron X-ray source can produce very high-quality data that may be augmented by phase-contrast information to enhance contrast. Tomographic data can be visualized in several ways, the most effective of which is the production of isosurface-based ‘virtual fossils’ that can be manipulated and dissected interactively. PMID:18426749

Continuous description of fluctuating eccentricities

NASA Astrophysics Data System (ADS)

Blaizot, Jean-Paul; Broniowski, Wojciech; Ollitrault, Jean-Yves

2014-11-01

We consider the initial energy density in the transverse plane of a high energy nucleus-nucleus collision as a random field ρ (x), whose probability distribution P [ ρ ], the only ingredient of the present description, encodes all possible sources of fluctuations. We argue that it is a local Gaussian, with a short-range 2-point function, and that the fluctuations relevant for the calculation of the eccentricities that drive the anisotropic flow have small relative amplitudes. In fact, this 2-point function, together with the average density, contains all the information needed to calculate the eccentricities and their variances, and we derive general model independent expressions for these quantities. The short wavelength fluctuations are shown to play no role in these calculations, except for a renormalization of the short range part of the 2-point function. As an illustration, we compare to a commonly used model of independent sources, and recover the known results of this model.

Progressive Failure Analysis Methodology for Laminated Composite Structures

NASA Technical Reports Server (NTRS)

Sleight, David W.

1999-01-01

A progressive failure analysis method has been developed for predicting the failure of laminated composite structures under geometrically nonlinear deformations. The progressive failure analysis uses C(exp 1) shell elements based on classical lamination theory to calculate the in-plane stresses. Several failure criteria, including the maximum strain criterion, Hashin's criterion, and Christensen's criterion, are used to predict the failure mechanisms and several options are available to degrade the material properties after failures. The progressive failure analysis method is implemented in the COMET finite element analysis code and can predict the damage and response of laminated composite structures from initial loading to final failure. The different failure criteria and material degradation methods are compared and assessed by performing analyses of several laminated composite structures. Results from the progressive failure method indicate good correlation with the existing test data except in structural applications where interlaminar stresses are important which may cause failure mechanisms such as debonding or delaminations.

Implementation of a kappa-epsilon turbulence model to RPLUS3D code

NASA Technical Reports Server (NTRS)

Chitsomboon, Tawit

1992-01-01

The RPLUS3D code has been developed at the NASA Lewis Research Center to support the National Aerospace Plane (NASP) project. The code has the ability to solve three dimensional flowfields with finite rate combustion of hydrogen and air. The combustion process of the hydrogen-air system are simulated by an 18 reaction path, 8 species chemical kinetic mechanism. The code uses a Lower-Upper (LU) decomposition numerical algorithm as its basis, making it a very efficient and robust code. Except for the Jacobian matrix for the implicit chemistry source terms, there is no inversion of a matrix even though a fully implicit numerical algorithm is used. A k-epsilon turbulence model has recently been incorporated into the code. Initial validations have been conducted for a flow over a flat plate. Results of the validation studies are shown. Some difficulties in implementing the k-epsilon equations to the code are also discussed.

Implementation of a kappa-epsilon turbulence model to RPLUS3D code

NASA Astrophysics Data System (ADS)

Chitsomboon, Tawit

1992-02-01

The RPLUS3D code has been developed at the NASA Lewis Research Center to support the National Aerospace Plane (NASP) project. The code has the ability to solve three dimensional flowfields with finite rate combustion of hydrogen and air. The combustion process of the hydrogen-air system are simulated by an 18 reaction path, 8 species chemical kinetic mechanism. The code uses a Lower-Upper (LU) decomposition numerical algorithm as its basis, making it a very efficient and robust code. Except for the Jacobian matrix for the implicit chemistry source terms, there is no inversion of a matrix even though a fully implicit numerical algorithm is used. A k-epsilon turbulence model has recently been incorporated into the code. Initial validations have been conducted for a flow over a flat plate. Results of the validation studies are shown. Some difficulties in implementing the k-epsilon equations to the code are also discussed.

Novel Route to Transition Metal Isothiocyanate Complexes Using Metal Powders and Thiourea

NASA Technical Reports Server (NTRS)

Harris, Jerry D.; Eckles, William E.; Hepp, Aloysius F.; Duraj, Stan A.; Hehemann, David G.; Fanwick, Phillip E.; Richardson, John

2003-01-01

A new synthetic route to isothiocyanate-containing materials is presented. Eight isothiocyanate- 4-methylpyridine (y-picoline) compounds were prepared by refluxing metal powders (Mn, Fe, Co, Ni, and Cu) with thiourea in y-picoline. With the exception of compound 5,prepared with Co, the isothiocyanate ligand was generated in situ by the isomerization of thiourea to NH4+SCN- at reflux temperatures. The complexes were characterized by x-ray crystallography. Compounds 1,2, and 8 are the first isothiocyanate- 4-methylpyridine anionic compounds ever prepared and structurally characterized. Compounds 1 and 2 are isostructural with four equatorially bound isothiocyanate ligands and two axially bound y-picoline molecules. Compound 8 is a five-coordinate copper(II) molecule with a distorted square-pyramidal geometry. Coordinated picoline and two isothiocyanates form the basal plane and the remaining isothiocyanate is bound at the apex. Structural data are presented for all compounds.

Machine-Washable PEDOT:PSS Dyed Silk Yarns for Electronic Textiles.

PubMed

Ryan, Jason D; Mengistie, Desalegn Alemu; Gabrielsson, Roger; Lund, Anja; Müller, Christian

2017-03-15

Durable, electrically conducting yarns are a critical component of electronic textiles (e-textiles). Here, such yarns with exceptional wear and wash resistance are realized through dyeing silk from the silkworm Bombyx mori with the conjugated polymer:polyelectrolyte complex PEDOT:PSS. A high Young's modulus of approximately 2 GPa combined with a robust and scalable dyeing process results in up to 40 m long yarns that maintain their bulk electrical conductivity of approximately 14 S cm -1 when experiencing repeated bending stress as well as mechanical wear during sewing. Moreover, a high degree of ambient stability is paired with the ability to withstand both machine washing and dry cleaning. For the potential use for e-textile applications to be illustrated, an in-plane thermoelectric module that comprises 26 p-type legs is demonstrated by embroidery of dyed silk yarns onto a piece of felted wool fabric.

Machine-Washable PEDOT:PSS Dyed Silk Yarns for Electronic Textiles

PubMed Central

2017-01-01

Durable, electrically conducting yarns are a critical component of electronic textiles (e-textiles). Here, such yarns with exceptional wear and wash resistance are realized through dyeing silk from the silkworm Bombyx mori with the conjugated polymer:polyelectrolyte complex PEDOT:PSS. A high Young’s modulus of approximately 2 GPa combined with a robust and scalable dyeing process results in up to 40 m long yarns that maintain their bulk electrical conductivity of approximately 14 S cm–1 when experiencing repeated bending stress as well as mechanical wear during sewing. Moreover, a high degree of ambient stability is paired with the ability to withstand both machine washing and dry cleaning. For the potential use for e-textile applications to be illustrated, an in-plane thermoelectric module that comprises 26 p-type legs is demonstrated by embroidery of dyed silk yarns onto a piece of felted wool fabric. PMID:28245105

3D super-resolution imaging with blinking quantum dots

PubMed Central

Wang, Yong; Fruhwirth, Gilbert; Cai, En; Ng, Tony; Selvin, Paul R.

2013-01-01

Quantum dots are promising candidates for single molecule imaging due to their exceptional photophysical properties, including their intense brightness and resistance to photobleaching. They are also notorious for their blinking. Here we report a novel way to take advantage of quantum dot blinking to develop an imaging technique in three-dimensions with nanometric resolution. We first applied this method to simulated images of quantum dots, and then to quantum dots immobilized on microspheres. We achieved imaging resolutions (FWHM) of 8–17 nm in the x-y plane and 58 nm (on coverslip) or 81 nm (deep in solution) in the z-direction, approximately 3–7 times better than what has been achieved previously with quantum dots. This approach was applied to resolve the 3D distribution of epidermal growth factor receptor (EGFR) molecules at, and inside of, the plasma membrane of resting basal breast cancer cells. PMID:24093439

Imbibition with swelling: Capillary rise in thin deformable porous media

NASA Astrophysics Data System (ADS)

Kvick, Mathias; Martinez, D. Mark; Hewitt, Duncan R.; Balmforth, Neil J.

2017-07-01

The imbibition of a liquid into a thin deformable porous substrate driven by capillary suction is considered. The substrate is initially dry and has uniform porosity and thickness. Two-phase flow theory is used to describe how the liquid flows through the pore space behind the wetting front when out-of-plane deformation of the solid matrix is considered. Neglecting gravity and evaporation, standard shallow-layer scalings are used to construct a reduced model of the dynamics. The model predicts convergence to a self-similar behavior in all regions except near the wetting front, where a boundary layer arises whose structure narrows with the advance of the front. Over time, the rise height approaches the similarity scaling of t1 /2, as in the classical Washburn or BCLW law. The results are compared with a series of laboratory experiments using cellulose paper sheets, which provide qualitative agreement.

Point defects in hexagonal germanium carbide monolayer: A first-principles calculation

NASA Astrophysics Data System (ADS)

Ersan, Fatih; Gökçe, Aytaç Gürhan; Aktürk, Ethem

2016-12-01

On the basis of first-principles plane-wave calculations, we investigated the electronic and magnetic properties of various point defects including single Ge and C vacancies, Ge + C divacancy, Ge↔C antisites and the Stone-Wales (SW) defects in a GeC monolayer. We found that various periodic vacancy defects in GeC single layer give rise to crucial effects on the electronic and magnetic properties. The band gaps of GeC monolayer vary significantly from 0.308 eV to 1.738 eV due to the presence of antisites and Stone-Wales defects. While nonmagnetic ground state of semiconducting GeC turns into metal by introducing a carbon vacancy, it becomes half-metal by a single Ge vacancy with high magnetization (4 μB) value per supercell. All the vacancy types have zero net magnetic moments, except single Ge vacancy.

Multiple Instantons Representing Higher-Order Chern-Pontryagin Classes

NASA Astrophysics Data System (ADS)

Spruck, Joel; Tchrakian, D. H.; Yang, Yisong

It has been shown in the work of Chakrabarti, Sherry and Tchrakian that the chiral SO+/-(4 p) Yang-Mills theory in the Euclidean 4 p (p>= 2) dimensions allows an axially symmetric self-dual system of equations similar to Witten's instanton equations in the classical 4-dimensional SU(2) SO+/-(4) theory and the solutions represent a new class of instantons. However the rigorous existence of these higher-dimensional instanton solutions has remained open except for the solution of unit charge representing a single instanton. In this paper we establish an existence and uniqueness theorem for multi-instantons of arbitrary charges in the case p>= 2. These solutions are the first known instantons, with the Chern-Pontryagin index greater than one, of the Yang-Mills model in higher dimensions. Our approach is a study of a nonlinear variational equation defined on the Poincaré half plane.

Three dimensional radiation fields in free electron lasers using Lienard-Wiechert fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elias, L.R.; Gallardo, J.

1981-10-28

In a free electron laser a relativistic electron beam is bunched under the action of the ponderomotive potential and is forced to radiate in close phase with the input wave. Until recently, most theories of the FEL have dealt solely with electron beams of infinite transverse dimension radiating only one-dimensional E.M. waves (plane waves). Although these theories describe accurately the dynamics of the electrons during the FEL interaction process, neither the three dimensional nature of the radiated fields nor its non-monochromatic features can be properly studied by them. As a result of this, very important practical issues such as themore » gain per gaussian-spherical optical mode in a free electron laser have not been well addressed, except through a one dimensional field model in which a filling factor describes crudely the coupling of the FEL induced field to the input field.« less

Life near the Roche limit - Behavior of ejecta from satellites close to planets

NASA Technical Reports Server (NTRS)

Dobrovolskis, A. R.; Burns, J. A.

1980-01-01

A study of the dynamics of nearby debris from impact craters was made to explain the distinctive features seen on Phobos, Deimis, and Amalthea. The planetary tides and satellite rotation were considered, and the usual pseudo-energy (Jacobi) integral was numerically calculated in the framework of a restricted body problem where satellites are modelled as triaxial ellipsoids rather than point masses. Iso-contours of this integral show that Deimos and Amalthea are entirely closed by Roche lobes, and the surfaces of their model ellipsoids lie nearly along equipotentials. Presently, the surface of Phobos overflows its Roche lobe, except for regions within a few km of the sub-Mars and anti-Mars points. The behavior of crater ejecta from the satellites of Mars were also examined by numerical integration of trajectories for particles leaving their surfaces in the equatorial plane.

Absence of metastable states in strained monoatomic cubic crystals.

NASA Astrophysics Data System (ADS)

Aguayo, Aarón; Mehl, Michael L.; de Coss, Romeo

2005-03-01

The Bain path distortion of a metal with an fcc (bcc) ground state toward the bcc (fcc) structure initially requires an increase in energy, but at some point along the Bain path the energy will again decrease until a local minimum is reached. We have studied the tetragonal distortion (Bain path) of monoatomic cubic crystals, using a combination of parametrized tight-binding and first-principles linearized augmented plane wave calculations. We show that this local minimum is unstable with respect to an elastic distortion, except in the rare case that the minimum is at the bcc (fcc) point on the Bain path. This shows that body-centered-tetragonal phases of these materials, which have been seen in epitaxially grown thin films, must be stabilized by the substrate and cannot be freestanding films. This work was partially supported by Consejo Nacional de Ciencia y Tecnolog'ia (CONACYT, M'exico) under Grant No. 43830-F.

An equilibrium method for prediction of transverse shear stresses in a thick laminated plate

NASA Technical Reports Server (NTRS)

Chaudhuri, R. Z.

1986-01-01

First two equations of equilibrium are utilized to compute the transverse shear stress variation through thickness of a thick laminated plate after in-plane stresses have been computed using an assumed quadratic displacement triangular element based on transverse inextensibility and layerwise constant shear angle theory (LCST). Centroid of the triangle is the point of exceptional accuracy for transverse shear stresses. Numerical results indicate close agreement with elasticity theory. An interesting comparison between the present theory and that based on assumed stress hybrid finite element approach suggests that the latter does not satisfy the condition of free normal traction at the edge. Comparison with numerical results obtained by using constant shear angle theory suggests that LCST is close to the elasticity solution while the CST is closer to classical (CLT) solution. It is also demonstrated that the reduced integration gives faster convergence when the present theory is applied to a thin plate.

Synchrotron radiation x-ray topography and defect selective etching analysis of threading dislocations in GaN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sintonen, Sakari, E-mail: sakari.sintonen@aalto.fi; Suihkonen, Sami; Jussila, Henri

2014-08-28

The crystal quality of bulk GaN crystals is continuously improving due to advances in GaN growth techniques. Defect characterization of the GaN substrates by conventional methods is impeded by the very low dislocation density and a large scale defect analysis method is needed. White beam synchrotron radiation x-ray topography (SR-XRT) is a rapid and non-destructive technique for dislocation analysis on a large scale. In this study, the defect structure of an ammonothermal c-plane GaN substrate was recorded using SR-XRT and the image contrast caused by the dislocation induced microstrain was simulated. The simulations and experimental observations agree excellently and themore » SR-XRT image contrasts of mixed and screw dislocations were determined. Apart from a few exceptions, defect selective etching measurements were shown to correspond one to one with the SR-XRT results.« less

Materials, devices, techniques, and applications for Z-plane focal plane array technology II; Proceedings of the Meeting, San Diego, CA, July 12, 13, 1990

NASA Astrophysics Data System (ADS)

Carson, John C.

1990-11-01

Various papers on materials, devices, techniques, and applications for X-plane focal plane array technology are presented. Individual topics addressed include: application of Z-plane technology to the remote sensing of the earth from GEO, applications of smart neuromorphic focal planes, image-processing of Z-plane technology, neural network Z-plane implementation with very high interconnection rates, using a small IR surveillance satellite for tactical applications, establishing requirements for homing applications, Z-plane technology. Also discussed are: on-array spike suppression signal processing, algorithms for on-focal-plane gamma circumvention and time-delay integration, current HYMOSS Z-technology, packaging of electrons for on- and off-FPA signal processing, space/performance qualification of tape automated bonded devices, automation in tape automated bonding, high-speed/high-volume radiometric testing of Z-technology focal planes, 128-layer HYMOSS-module fabrication issues, automation of IRFPA production processes.

14 CFR 29.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... terms of minimum intensities in the horizontal plane, minimum intensities in any vertical plane, and... requirements: (1) Intensities in the horizontal plane. Each intensity in the horizontal plane (the plane containing the longitudinal axis of the rotorcraft and perpendicular to the plane of symmetry of the...

14 CFR 27.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... minimum intensities in the horizontal plane, minimum intensities in any vertical plane, and maximum...: (1) Intensities in the horizontal plane. Each intensity in the horizontal plane (the plane containing the longitudinal axis of the rotorcraft and perpendicular to the plane of symmetry of the rotorcraft...

14 CFR 25.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... minimum intensities in the horizontal plane, minimum intensities in any vertical plane, and maximum...: (1) Intensities in the horizontal plane. Each intensity in the horizontal plane (the plane containing the longitudinal axis of the airplane and perpendicular to the plane of symmetry of the airplane) must...

Effects of Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper plus radiometric and geometric calibrations and corrections on landscape characterization

USGS Publications Warehouse

Vogelmann, James E.; Helder, Dennis; Morfitt, Ron; Choate, Michael J.; Merchant, James W.; Bulley, Henry

2001-01-01

The Thematic Mapper (TM) instruments onboard Landsats 4 and 5 provide high-quality imagery appropriate for many different applications, including land cover mapping, landscape ecology, and change detection. Precise calibration was considered to be critical to the success of the Landsat 7 mission and, thus, issues of calibration were given high priority during the development of the Enhanced Thematic Mapper Plus (ETM+). Data sets from the Landsat 5 TM are not routinely corrected for a number of radiometric and geometric artifacts, including memory effect, gain/bias, and interfocal plane misalignment. In the current investigation, the effects of correcting vs. not correcting these factors were investigated for several applications. Gain/bias calibrations were found to have a greater impact on most applications than did memory effect calibrations. Correcting interfocal plane offsets was found to have a moderate effect on applications. On June 2, 1999, Landsats 5 and 7 data were acquired nearly simultaneously over a study site in the Niobrara, NE area. Field radiometer data acquired at that site were used to facilitate crosscalibrations of Landsats 5 and 7 data. Current findings and results from previous investigations indicate that the internal calibrator of Landsat 5 TM tracked instrument gain well until 1988. After this, the internal calibrator diverged from the data derived from vicarious calibrations. Results from this study also indicate very good agreement between prelaunch measurements and vicarious calibration data for all Landsat 7 reflective bands except Band 4. Values are within about 3.5% of each other, except for Band 4, which differs by 10%. Coefficient of variation (CV) values derived from selected targets in the imagery were also analyzed. The Niobrara Landsat 7 imagery was found to have lower CV values than Landsat 5 data, implying that lower levels of noise characterize Landsat 7 data than current Landsat 5 data. It was also found that following radiometric normalization, the Normalized Difference Vegetation Index (NDVI) imagery and classification products of Landsats 5 and 7 were very similar. This implies that data from the two sensors can be used to measure and monitor the same landscape phenomena and that Landsats 5 and 7 data can be used interchangeably with proper caution. In addition, it was found that difference imagery produced using Landsat 7 ETM+ data are of excellent quality.

NCC-RANSAC: a fast plane extraction method for 3-D range data segmentation.

PubMed

Qian, Xiangfei; Ye, Cang

2014-12-01

This paper presents a new plane extraction (PE) method based on the random sample consensus (RANSAC) approach. The generic RANSAC-based PE algorithm may over-extract a plane, and it may fail in case of a multistep scene where the RANSAC procedure results in multiple inlier patches that form a slant plane straddling the steps. The CC-RANSAC PE algorithm successfully overcomes the latter limitation if the inlier patches are separate. However, it fails if the inlier patches are connected. A typical scenario is a stairway with a stair wall where the RANSAC plane-fitting procedure results in inliers patches in the tread, riser, and stair wall planes. They connect together and form a plane. The proposed method, called normal-coherence CC-RANSAC (NCC-RANSAC), performs a normal coherence check to all data points of the inlier patches and removes the data points whose normal directions are contradictory to that of the fitted plane. This process results in separate inlier patches, each of which is treated as a candidate plane. A recursive plane clustering process is then executed to grow each of the candidate planes until all planes are extracted in their entireties. The RANSAC plane-fitting and the recursive plane clustering processes are repeated until no more planes are found. A probabilistic model is introduced to predict the success probability of the NCC-RANSAC algorithm and validated with real data of a 3-D time-of-flight camera-SwissRanger SR4000. Experimental results demonstrate that the proposed method extracts more accurate planes with less computational time than the existing RANSAC-based methods.

NCC-RANSAC: A Fast Plane Extraction Method for 3-D Range Data Segmentation

PubMed Central

Qian, Xiangfei; Ye, Cang

2015-01-01

This paper presents a new plane extraction (PE) method based on the random sample consensus (RANSAC) approach. The generic RANSAC-based PE algorithm may over-extract a plane, and it may fail in case of a multistep scene where the RANSAC procedure results in multiple inlier patches that form a slant plane straddling the steps. The CC-RANSAC PE algorithm successfully overcomes the latter limitation if the inlier patches are separate. However, it fails if the inlier patches are connected. A typical scenario is a stairway with a stair wall where the RANSAC plane-fitting procedure results in inliers patches in the tread, riser, and stair wall planes. They connect together and form a plane. The proposed method, called normal-coherence CC-RANSAC (NCC-RANSAC), performs a normal coherence check to all data points of the inlier patches and removes the data points whose normal directions are contradictory to that of the fitted plane. This process results in separate inlier patches, each of which is treated as a candidate plane. A recursive plane clustering process is then executed to grow each of the candidate planes until all planes are extracted in their entireties. The RANSAC plane-fitting and the recursive plane clustering processes are repeated until no more planes are found. A probabilistic model is introduced to predict the success probability of the NCC-RANSAC algorithm and validated with real data of a 3-D time-of-flight camera–SwissRanger SR4000. Experimental results demonstrate that the proposed method extracts more accurate planes with less computational time than the existing RANSAC-based methods. PMID:24771605

Bi-material plane with interface crack for the model of semi-linear material

NASA Astrophysics Data System (ADS)

Domanskaya, T. O.; Malkov, V. M.; Malkova, Yu. V.

2018-05-01

The singular plane problems of nonlinear elasticity (plane strain and plane stress) are considered for bi-material infinite plane with interface crack. The plane is formed of two half-planes. Mechanical properties of half-planes are described by the model of semi-linear material. Using model of this harmonic material has allowed to apply the theory of complex functions and to obtain exact analytical global solutions of some nonlinear problems. Among them the problem of bi-material plane with the stresses and strains jumps at an interface is considered. As an application of the problem of jumps, the problem of interface crack is solved. The values of nominal (Piola) and Cauchy stresses and displacements are founded. Based on the global solutions the asymptotic expansions are constructed for stresses and displacements in a vicinity of crack tip. As an example the case of a free crack in bi-material plane subjected to constant stresses at infinity is studied. As a special case, the analytical solution of the problem of a crack in a homogeneous plane is obtained from the problem for bi-material plane with interface crack.

Source Process of the 2007 Niigata-ken Chuetsu-oki Earthquake Derived from Near-fault Strong Motion Data

NASA Astrophysics Data System (ADS)

Aoi, S.; Sekiguchi, H.; Morikawa, N.; Ozawa, T.; Kunugi, T.; Shirasaka, M.

2007-12-01

The 2007 Niigata-ken Chuetsu-oki earthquake occurred on July 16th, 2007, 10:13 JST. We performed a multi- time window linear waveform inversion analysis (Hartzell and Heaton, 1983) to estimate the rupture process from the near fault strong motion data of 14 stations from K-NET, KiK-net, F-net, JMA, and Niigata prefecture. The fault plane for the mainshock has not been clearly determined yet from the aftershock distribution, so that we performed two waveform inversions for north-west dipping fault (Model A) and south-east dipping fault (Model B). Their strike, dip, and rake are set to those of the moment tensor solutions by F-net. Fault plane model of 30 km length by 24 km width is set to cover aftershock distribution within 24 hours after the mainshock. Theoretical Green's functions were calculated by the discrete wavenumber method (Bouchon, 1981) and the R/T matrix method (Kennett, 1983) with the different stratified medium for each station based on the velocity structure including the information form the reflection survey and borehole logging data. Convolution of moving dislocation was introduced to represent the rupture propagation in an each subfault (Sekiguchi et al., 2002). The observed acceleration records were integrated into velocity except of F-net velocity data, and bandpass filtered between 0.1 and 1.0 Hz. We solved least-squared equation to obtain slip amount of each time window on each subfault to minimize squared residual of the waveform fitting between observed and synthetic waveforms. Both models provide moment magnitudes of 6.7. Regarding Model A, we obtained large slip in the south-west deeper part of the rupture starting point, which is close to Kashiwazaki-city. The second or third velocity pulses of observed velocity waveforms seem to be composed of slip from the asperity. Regarding Model B, we obtained large slip in the southwest shallower part of the rupture starting point, which is also close to Kashiwazaki-city. In both models, we found small slip near the rupture starting point, and largest slip at about ten kilometer in the south-west of the rupture starting point with the maximum slip of 2.3 and 2.5 m for Models A and B, respectively. The difference of the residual between observed and synthetic waveforms for both models is not significant, therefore it is difficult to conclude which fault plane is appropriate to explain. The estimated large-slip regions in the inverted source models with the Models A and B are located near the cross point of the two fault plane models, which should have similar radiation pattern. This situation may be one of the reasons why judgment of the fault plane orientation is such difficult. We need careful examinations not only strong motion data but also geodetic data to further explore the fault orientation and the source process of this earthquake.

2. VIEW SOUTH, INCLINE PLANE CAR, INCLINE PLANE TRACK, UPPER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. VIEW SOUTH, INCLINE PLANE CAR, INCLINE PLANE TRACK, UPPER STATION. - Monongahela Incline Plane, Connecting North side of Grandview Avenue at Wyoming Street with West Carson Street near Smithfield Street, Pittsburgh, Allegheny County, PA

Growth and Crystal Orientation of ZnTe on m-Plane Sapphire with Nanofaceted Structure

NASA Astrophysics Data System (ADS)

Nakasu, Taizo; Sun, Wei-Che; Kobayashi, Masakazu; Asahi, Toshiaki

2017-04-01

ZnTe thin films on sapphire substrate with nanofaceted structure have been studied. The nanofaceted structure of the m-plane (10-10) sapphire was obtained by heating the substrate at above 1100°C in air, and the r-plane (10-12) and S-plane (1-101) were confirmed. ZnTe layers were prepared on the nanofaceted m-plane sapphire substrates by molecular beam epitaxy (MBE). The effect of the nanofaceted structure on the orientation of the thin films was examined based on x-ray diffraction (XRD) pole figures. Transmission electron microscopy (TEM) was also employed to characterize the interface structures. The ZnTe layer on the nanofaceted m-plane sapphire substrate exhibited (331)-plane orientation, compared with (211)-plane without the nanofaceted structure. After thermal treatment, the m-plane surface vanished and (211) layer could not be formed because of the lack of surface lattice matching. On the other hand, (331)-plane thin film was formed on the nanofaceted m-plane sapphire substrate, since the (111) ZnTe domains were oriented on the S-facet. The orientation of the ZnTe epilayer depended on the atomic ordering on the surface and the influence of the S-plane.

Comparison of Skeletal and Dental Reference Planes with the Hamulus-Incisive-Papilla Plane: A Pilot Study on 3D Reconstructed Tomographies of the Skull.

PubMed

Pittschieler, Elisabeth; Foltin, Andrea; Falkensammer, Frank; Figl, Michael; Birkfellner, Wolfgang; Jonke, Erwin; Bantleon, Hans-Peter

2016-01-01

The aim of this study was to investigate the hamulus-incisive-papilla (HIP) plane as an alternative for transferring the three-dimensional position of a patient's maxilla to an articulator. Camper, Frankfurt horizontal, occlusal, and HIP planes were evaluated in 21 patients' computed tomography scans and compared to one another. Analysis of variance showed significant differences between all planes, with the HIP plane being closest to the occlusal plane (HIP-OP: 0.6 ± 4.0 degrees). Frankfurt and Camper planes, being more peripheral, showed higher geometric asymmetries. The HIP plane, when used for articulator mounting, results in a closer and more technically reliable patient relationship in a clinical and laboratory context.

A three-dimensional comparison of a morphometric and conventional cephalometric midsagittal planes for craniofacial asymmetry.

PubMed

Damstra, Janalt; Fourie, Zacharias; De Wit, Marnix; Ren, Yijin

2012-02-01

Morphometric methods are used in biology to study object symmetry in living organisms and to determine the true plane of symmetry. The aim of this study was to determine if there are clinical differences between three-dimensional (3D) cephalometric midsagittal planes used to describe craniofacial asymmetry and a true symmetry plane derived from a morphometric method based on visible facial features. The sample consisted of 14 dry skulls (9 symmetric and 5 asymmetric) with metallic markers which were imaged with cone-beam computed tomography. An error study and statistical analysis were performed to validate the morphometric method. The morphometric and conventional cephalometric planes were constructed and compared. The 3D cephalometric planes constructed as perpendiculars to the Frankfort horizontal plane resembled the morphometric plane the most in both the symmetric and asymmetric groups with mean differences of less than 1.00 mm for most variables. However, the standard deviations were often large and clinically significant for these variables. There were clinically relevant differences (>1.00 mm) between the different 3D cephalometric midsagittal planes and the true plane of symmetry determined by the visible facial features. The difference between 3D cephalometric midsagittal planes and the true plane of symmetry determined by the visible facial features were clinically relevant. Care has to be taken using cephalometric midsagittal planes for diagnosis and treatment planning of craniofacial asymmetry as they might differ from the true plane of symmetry as determined by morphometrics.

Comparison of full-mouth disinfection and quadrant-wise scaling in the treatment of adult chronic periodontitis: a systematic review and meta-analysis.

PubMed

Fang, H; Han, M; Li, Q-L; Cao, C Y; Xia, R; Zhang, Z-H

2016-08-01

Scaling and root planing are widely considered as effective methods for treating chronic periodontitis. A meta-analysis published in 2008 showed no statistically significant differences between full-mouth disinfection (FMD) or full-mouth scaling and root planing (FMS) and quadrant scaling and root planing (Q-SRP). The FMD approach only resulted in modest additional improvements in several indices. Whether differences exist between these two approaches requires further validation. Accordingly, a study was conducted to further validate whether FMD with antiseptics or FMS without the use of antiseptics within 24 h provides greater clinical improvement than Q-SRP in patients with chronic periodontitis. Medline (via OVID), EMBASE (via OVID), PubMed and CENTRAL databases were searched up to 27 January 2015. Randomized controlled trials comparing FMD or FMS with Q-SRP after at least 3 mo were included. Meta-analysis was performed to obtain the weighted mean difference (WMD), together with the corresponding 95% confidence intervals. Thirteen articles were included in the meta-analysis. The WMD of probing pocket depth reduction was 0.25 mm (p < 0.05) for FMD vs. Q-SRP in single-rooted teeth with moderate pockets, and clinical attachment level gain in single- and multirooted teeth with moderate pockets was 0.33 mm (p < 0.05) for FMD vs. Q-SRP. Except for those, no statistically significant differences were found in the other subanalyses of FMD vs. Q-SRP, FMS vs. Q-SRP and FMD vs. FMS. Therefore, the meta-analysis results showed that FMD was better than Q-SRP for achieving probing pocket depth reduction and clinical attachment level gain in moderate pockets. Additionally, regardless of the treatment, no serious complications were observed. FMD, FMS and Q-SRP are all effective for the treatment of adult chronic periodontitis, and they do not lead to any obvious discomfort among patients. Moreover, FMD had modest additional clinical benefits over Q-SRP, so we prefer to recommend FMD as the first choice for the treatment of adult chronic periodontitis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The WIYN One Degree Imager - Status and Performance

NASA Astrophysics Data System (ADS)

Boroson, Todd A.

2013-06-01

A preliminary version of the WIYN One Degree Imager (ODI) has been commissioned and put into scientific operation. ODI was designed to take advantage of the excellent image quality and wide field of view of the WIYN 3.5m telescope. It will do this by covering a one square degree focal plane with orthogonal transfer array (OTA) detectors, which have the capability to correct for image motion during the exposure in regions approximately the size of the isokinetic patch. The partial ODI (pODI) differs from the complete ODI in two ways - only 13 of the 64 OTAs populate the focal plane, and only coherent image motion correction is enabled. However, this implementation has allowed the commissioning of the instrument with all subsystems except the additional detectors in place. The 13 OTAs are configured as a 24 X 24 arcminute “science field”, plus 4 outer OTAs, allowing the sampling of all radii within the one square degree field. pODI is now in use for science observations as we prepare to upgrade the focal plane. The performance of pODI is excellent. Image quality is site seeing limited, and, on good seeing nights, we can achieve images around 0.4 arcsec FWHM over the entire field. The guide signal, from selected regions in the outer OTAs, can be passed to the telescope exclusively, or the high frequency component can be applied as a global shift to the OTAs. We are still in the process of characterizing the gains from this coherent correction, but the detectors perform well in this mode. Data are immediately transferred to an archive at Indiana University, where they are pipeline-processed to remove instrumental signature. The OTA detectors perform adequately in terms of read noise, full well, sensitivity, and dark current. They show 2 anomalies: (1) regions in the circuitry outside the imaging area glow under certain circumstances, and (2) a low level degradation of charge transfer efficiency is present between the imaging area and the serial registers. We have found ways to address both of these effects in operation, calibration, and post-processing, and the instrument is producing valuable scientific observations.

SU-E-T-790: Validation of 4D Measurement-Guided Dose Reconstruction (MGDR) with OCTAVIUS 4D System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, V; Leung, R; Wong, M

2015-06-15

Purpose: To validate the MGDR of OCTAVIUS 4D system (PTW, Freiburg, Germany) for quality assurance (QA) of volumetric-modulated arc radiotherapy (VMAT). Methods: 4D-MGDR measurements were divided into two parts: 1) square fields from 2×2 to 25×25 cm{sup 2} at 0°, 10° and 45° gantry, and 2) 8 VMAT plans (5 nasopharyngeal and 3 prostate) collapsed to gantry 40° in QA mode in Monaco v5.0 (Elekta, CMS, Maryland Heights, MO) were delivered on the OCTAVIUS 4D phantom with the OCTAVIUS 1500 detector plane perpendicular to either the incident beam to obtain the reconstructed dose (OCTA4D) or the 0° gantry axis tomore » obtain the raw doses (OCTA3D) in Verisoft 6.1 (PTW, Freiburg, Germany). Raw measurements of OCTA3D were limited to < 45° gantry to avoid >0.5% variation of detector angular response with respect to 0° gantry as determined previously. Reconstructed OCTA4D and raw OCTA3D doses for all plans were compared at the same detector plane using γ criteria of 2% (local dose)/2mm and 3%/3mm criteria. Results: At gantry 0° and 10°, the γ results for all OCTA4D on detector plane coinciding with OCTA3D were over 90% at 2%/2mm except for the largest field (25×25 cm{sup 2} ) showing >88%. For square field at 45° gantry, γ passing rate is > 90% for fields smaller than 15x 15cm2 but < 80% for field size of 20 x20 cm{sup 2} upward. For VMAT, γ results showed 94% and 99% passing rate at 2%/2mm and 3%/3mm, respectively. Conclusion: OCTAVIUS 4D system has compromised accuracy in reconstructing dose away from the central beam axis, possibly due to the off-axis softening correction and errors of the percent depth dose data necessary as input for MGDR. Good results in VMAT delivery suggested that the system is relatively reliable for VMAT with small segments.« less

Advanced Liquid-Cooling Garment Using Highly Thermally Conductive Sheets

NASA Technical Reports Server (NTRS)

Ruemmele, Warren P.; Bue, Grant C.; Orndoff, Evelyne; Tang, Henry

2010-01-01

This design of the liquid-cooling garment for NASA spacesuits allows the suit to remove metabolic heat from the human body more effectively, thereby increasing comfort and performance while reducing system mass. The garment is also more flexible, with fewer restrictions on body motion, and more effectively transfers thermal energy from the crewmember s body to the external cooling unit. This improves the garment s performance in terms of the maximum environment temperature in which it can keep a crewmember comfortable. The garment uses flexible, highly thermally conductive sheet material (such as graphite), coupled with cooling water lines of improved thermal conductivity to transfer the thermal energy from the body to the liquid cooling lines more effectively. The conductive sheets can be layered differently, depending upon the heat loads, in order to provide flexibility, exceptional in-plane heat transfer, and good through-plane heat transfer. A metal foil, most likely aluminum, can be put between the graphite sheets and the external heat source/sink in order to both maximize through-plane heat transfer at the contact points, and to serve as a protection to the highly conductive sheets. Use of a wicking layer draws excess sweat away from the crewmember s skin and the use of an outer elastic fabric ensures good thermal contact of the highly conductive underlayers with the skin. This allows the current state of the art to be improved by having cooling lines that can be more widely spaced to improve suit flexibility and to reduce weight. Also, cooling liquid does not have to be as cold to achieve the same level of cooling. Specific areas on the human body can easily be targeted for greater or lesser cooling to match human physiology, a warmer external environment can be tolerated, and spatial uniformity of the cooling garment can be improved to reduce vasoconstriction limits. Elements of this innovation can be applied to other embodiments to provide effective heat transfer over a flexible and surface-conformable fashion without the limitation of fluid freeze points.

49 CFR 572.42 - Thorax.

Code of Federal Regulations, 2010 CFR

2010-10-01

... side of the vehicle. The probe's centerline is perpendicular to thorax's midsagittal plane. (3) Align... of the transverse and frontal planes perpendicular to the chest's midsagittal plane passing through... midsagittal plane and tangential plane to the Hinge Mounting Block (Drawing SID-034) are vertical. (5) Impact...

Determining The Plane of The Kuiper Belt with OSSOS

NASA Astrophysics Data System (ADS)

Van Laerhoven, Christa; Kavelaars, J. J.; Volk, Kathryn; Gladman, Brett; Petit, Jean-Marc

2018-04-01

We present the OSSOS-based measurement of the semi-major axes dependent orientation of the Kuiper Belt plane. A Kuiper Belt object's (KBO's) inclination can be broken down into a forced component and a free component. The inclination and longitude of ascending node of the forced inclination define the 'forced plane,' the plane about which the KBO's inclination will precess. Secular theory predicts that this forced plane should depend on semi-major axis. For example, the nu18 secular resonance should create a significant warp in the forced planet near 40.5 au (Chiang and Choi 2008). Not predicted by secular theory is a warp in the distant Kuiper Belt (semi-major axes greater than 50 au) seen by Volk and Malhotra 2016 using KBOs from the Minor Planet Catalog. We investigate what the inclination distribution is for objects beyond Neptune as a function of semi-major axis using the OSSOS characterized sample. Through use of the OSSOS survey simulator we test various underlying orbital distributions and compare how the survey would have observed those populations to the actual observed sample. In particular, we test various widths for the inclination distribution about various local forcing planes for the kernel, stirred, and hot classical Kuiper Belt. We find that the forced plane in matches well with the expected forced plane from secular theory. Through most of the main Kuiper Belt (between the 3:2 and 2:1 resonances), we can reject both the ecliptic plane and the invariable plane as the true forced plane. Only as the expected secularly forced plane approaches the invariable plane does the invariable plane become non-rejectable. In the outer Kuiper Belt we reject the nominal mean-plane measured by Volk and Malhotra, but smaller warps are still allowed by the data.

Out-of-plane coercive field of Ni 80Fe 20 antidot arrays

NASA Astrophysics Data System (ADS)

Gao, Chunhong; Chen, Ke; Lü, Ling; Zhao, Jianwei; Chen, Peng

2010-11-01

The out-of-plane magnetic anisotropy and out-of-plane magnetization reversal process of nanoscale Ni 80Fe 20 antidot arrays deposited by magnetron sputtering technique on an anodic aluminum oxide (AAO) membrane are investigated. The angular dependence of out-of-plane remanent magnetization of Ni 80Fe 20 antidot arrays shows that the maximum remanence is in-plane and the squareness of the out-of-plane hysteresis loop follow a |cos θ| dependence. The angular dependence of out-of-plane coercivity of Ni 80Fe 20 antidot arrays shows that the maximum coercivity lies on the surface of a cone with its symmetric axis normal to the sample plane, which indicates a transition of magnetic reversal from curling to coherent rotation when changing the angle between the applied magnetic field and the sample plane.

Phase formation and strain relaxation of Ga2O3 on c-plane and a-plane sapphire substrates as studied by synchrotron-based x-ray diffraction

NASA Astrophysics Data System (ADS)

Cheng, Zongzhe; Hanke, Michael; Vogt, Patrick; Bierwagen, Oliver; Trampert, Achim

2017-10-01

Heteroepitaxial Ga2O3 was deposited on c-plane and a-plane oriented sapphire by plasma-assisted molecular beam epitaxy and probed by ex-situ and in-situ synchrotron-based x-ray diffraction. The investigation on c-plane sapphire determined a critical thickness of around 33 Å, at which the monoclinic β-phase forms on top of the hexagonal α-phase. A 143 Å thick single phase α-Ga2O3 was observed on a-plane sapphire, much thicker than the α-Ga2O3 on c-plane sapphire. The α-Ga2O3 relaxed very fast in the first 30 Å in both out-of-plane and in-plane directions as measured by the in-situ study.

Ultrastructure of spermatozoa of tench Tinca tinca observed by means of scanning and transmission electron microscopy.

PubMed

Psenicka, M; Rodina, M; Nebesarova, J; Linhart, O

2006-09-15

Structure of tench (Tinca tinca L.) spermatozoa was investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Spermatozoa of 26.1+/-3.8 microm total length possessed typical primitive simple structure, called "aqua sperm", without acrosomal head structures. It was probably the smallest spermatozoon described among cyprinid fishes. Heads were mostly composed of dense and slightly granular material, which appeared to be fairly homogeneous except for the occasional appearance of vacuoles. The midpiece remained separated from the flagellum by the cytoplasmic channel; it was cylindric/cone-shaped, 0.86+/-0.27 microm in length and 1.17+/-0.24 microm in width at proximal part. The proximal centriole was located in the "implantation fossa". The distal centriole appeared almost tangential to the nucleus and it functioned as a basal body for the flagellum. It had an orientation of 140 degrees with respect to the distal centriole. The sperm flagellum with 25.45+/-2.47 microm of total length had no any fin. The diameter of the flagellum perpendicular to the plane of the doublet of central microtubules was 173.67+/-20.45 nm and horizontal plane of the central microtubules was 200.71+/-20.45 nm. Peripheral doublets and the central doublet of microtubules measured 23.39+/-3.18 and 35.88+/-4.44 nm in width, respectively. The diameter of a microtubule was only 9.14+/-2.97 nm. A vesicle was attached to the most basal region of the flagellum and located just under plasma membrane of the flagellum.

A survey of interstellar HI from L alpha absorption measurements 2

NASA Technical Reports Server (NTRS)

Bohlin, R. C.; Savage, B. D.; Drake, J. F.

1977-01-01

The Copernicus satellite surveyed the spectral region near L alpha to obtain column densities of interstellar HI toward 100 stars. The distance to 10 stars exceeds 2 kpc and 34 stars lie beyond 1 kpc. Stars with color excess E(B-V) up to 0.5 mag are observed. The value of the mean ratio of total neutral hydrogen to color excess was found to equal 5.8 x 10 to the 21st power atoms per (sq cm x mag). For stars with accurate E(B-V), the deviations from this mean are generally less than a factor of 1.5. A notable exception is the dark cloud star, rho Oph. A reduction in visual reddening efficiency for the grains that are larger than normal in the rho Oph dark cloud probably explains this result. The conversion of atomic hydrogen into molecular form in dense clouds was observed in the gas to E(B-V) correlation plots. The best estimate for the mean total gas density for clouds and the intercloud medium, as a whole, in the solar neighborhood and in the plane of the galaxy is 1.15 atoms per cu. cm; those for the atomic gas and molecular gas alone are 0.86 atoms per cu cm and 0.143 molecules per cu cm respectively. For the intercloud medium, where molecular hydrogen is a negligible fraction of the total gas, atomic gas density was found to equal 0.16 atoms per cu cm with a Gaussian scale height perpendicular to the plane of about 350 pc, as derived from high latitude stars.

The Incidence of Furcation Region Patency in Molars Before and After Simulated Periodontal Therapy.

PubMed

Shambarger, Sandra; Johnson, Deborah; Versulius-Tantbirojin, Daranee; Bowles, Walter R; McClanahan, Scott B

2015-01-01

To determine if there is increased bacterial communication through the furcation region in molar teeth after simulated periodontal therapy. Sixty-five extracted first and second molars were accessed and the roots were sectioned 4 mm apical to the furcation. The canals and external suface of the root were sealed except the furcation region. In Phase I, the teeth were sterilized and then suspended in Rogosa SL broth. A broth containing Lactobacillus casei was placed in the pulp chamber. The Rogosa SL broth in the bottom chamber was monitored daily for 30 days for turbidity, and once turbidly was noted, the broth was plated to confirm the presence of L. casei. In Phase II, the furcation regions were scaled and cementum removed, the teeth were sterilized, and the microbial leakage was repeated. The Phase I and Phase II median times to turbidity were 9.5 days and 4 days, respectively, and the difference was statistically significant (p = 0.0035). Phase I turbidity rate was 86.5%, and Phase II was 92.3%, which was not statistically significant (p = 0.25). The root canal system communicated with the furcation region an average of 86.5% and 92.5% after scaling and root planing during the 30 days of the experiment. The time of leakage between the two groups decreased from 9.5 to 4 days (p = 0.0035). Periodontal instrumentation of the furcation region in molar teeth can increase the risk of bacterial contamination by 39% while shortening the time for bacterial penetration in teeth with exposed dentin or furcation canals. accessory canals, scaling, and root planing.

Core strength and lower extremity alignment during single leg squats.

PubMed

Willson, John D; Ireland, Mary Lloyd; Davis, Irene

2006-05-01

Muscles of the trunk, hip, and knee influence the orientation of the lower extremity during weight bearing activities. The purpose of this study was threefold: first, to compare the orientation of the lower extremity during a single leg (SL) squat among male and female athletes; second, to compare the strength of muscle groups in the trunk, hips, and knees between these individuals; and third, to evaluate the association between trunk, hip, and knee strength and the orientation of the knee joint during this activity. Twenty-four male and 22 female athletes participated in this study. Peak isometric torque was determined for the following muscle actions: trunk flexion, extension, and lateral flexion, hip abduction and external rotation, and knee flexion and extension. The frontal plane projection angle (FPPA) of the knee during a 45 degrees SL squat was determined using photo editing software. Males and females moved in opposite directions during the SL squat test (F(1,42) = 5.05, P = 0.03). Females typically moved toward more extreme FPPA during SL squats (P = 0.056), while males tended to move toward more neutral alignment (P = 0.066). Females also generated less torque in all muscle groups, with the exception of trunk extension. The projection angle of the knee during the SL squat test was most closely associated with hip external rotation strength. Using instruments suitable for a clinical setting, females were found to have greater FPPA and generally decreased trunk, hip, and knee isometric torque. Hip external rotation strength was most closely associated with the frontal plane projection angle.

Spatial resolution measurements by Radia diagnostic software with SEDENTEXCT image quality phantom in cone beam CT for dental use.

PubMed

Watanabe, Hiroshi; Nomura, Yoshikazu; Kuribayashi, Ami; Kurabayashi, Tohru

2018-02-01

We aimed to employ the Radia diagnostic software with the safety and efficacy of a new emerging dental X-ray modality (SEDENTEXCT) image quality (IQ) phantom in CT, and to evaluate its validity. The SEDENTEXCT IQ phantom and Radia diagnostic software were employed. The phantom was scanned using one medical full-body CT and two dentomaxillofacial cone beam CTs. The obtained images were imported to the Radia software, and the spatial resolution outputs were evaluated. The oversampling method was employed using our original wire phantom as a reference. The resultant modulation transfer function (MTF) curves were compared. The null hypothesis was that MTF curves generated using both methods would be in agreement. One-way analysis of variance tests were applied to the f50 and f10 values from the MTF curves. The f10 values were subjectively confirmed by observing the line pair modules. The Radia software reported the MTF curves on the xy-plane of the CT scans, but could not return f50 and f10 values on the z-axis. The null hypothesis concerning the reported MTF curves on the xy-plane was rejected. There were significant differences between the results of the Radia software and our reference method, except for f10 values in CS9300. These findings were consistent with our line pair observations. We evaluated the validity of the Radia software with the SEDENTEXCT IQ phantom. The data provided were semi-automatic, albeit with problems and statistically different from our reference. We hope the manufacturer will overcome these limitations.

Optomechanical System Development of the AWARE Gigapixel Scale Camera

NASA Astrophysics Data System (ADS)

Son, Hui S.

Electronic focal plane arrays (FPA) such as CMOS and CCD sensors have dramatically improved to the point that digital cameras have essentially phased out film (except in very niche applications such as hobby photography and cinema). However, the traditional method of mating a single lens assembly to a single detector plane, as required for film cameras, is still the dominant design used in cameras today. The use of electronic sensors and their ability to capture digital signals that can be processed and manipulated post acquisition offers much more freedom of design at system levels and opens up many interesting possibilities for the next generation of computational imaging systems. The AWARE gigapixel scale camera is one such computational imaging system. By utilizing a multiscale optical design, in which a large aperture objective lens is mated with an array of smaller, well corrected relay lenses, we are able to build an optically simple system that is capable of capturing gigapixel scale images via post acquisition stitching of the individual pictures from the array. Properly shaping the array of digital cameras allows us to form an effectively continuous focal surface using off the shelf (OTS) flat sensor technology. This dissertation details developments and physical implementations of the AWARE system architecture. It illustrates the optomechanical design principles and system integration strategies we have developed through the course of the project by summarizing the results of the two design phases for AWARE: AWARE-2 and AWARE-10. These systems represent significant advancements in the pursuit of scalable, commercially viable snapshot gigapixel imaging systems and should serve as a foundation for future development of such systems.

Comparison of reconstructed rapid prototyping models produced by 3-dimensional printing and conventional stone models with different degrees of crowding.

PubMed

Wan Hassan, Wan Nurazreena; Yusoff, Yusnilawati; Mardi, Noor Azizi

2017-01-01

Rapid prototyping models can be reconstructed from stereolithographic digital study model data to produce hard-copy casts. In this study, we aimed to compare agreement and accuracy of measurements made with rapid prototyping and stone models for different degrees of crowding. The Z Printer 450 (3D Systems, Rock Hill, SC) reprinted 10 sets of models for each category of crowding (mild, moderate, and severe) scanned using a structured-light scanner (Maestro 3D, AGE Solutions, Pisa, Italy). Stone and RP models were measured using digital calipers for tooth sizes in the mesiodistal, buccolingual, and crown height planes and for arch dimension measurements. Bland-Altman and paired t test analyses were used to assess agreement and accuracy. Clinical significance was set at ±0.50 mm. Bland-Altman analysis showed the mean bias of measurements between the models to be within ±0.15 mm (SD, ±0.40 mm), but the 95% limits of agreement exceeded the cutoff point of ±0.50 mm (lower range, -0.81 to -0.41 mm; upper range, 0.34 to 0.76 mm). Paired t tests showed statistically significant differences for all planes in all categories of crowding except for crown height in the moderate crowding group and arch dimensions in the mild and moderate crowding groups. The rapid prototyping models were not clinically comparable with conventional stone models regardless of the degree of crowding. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

In-Flight Performance of the TES Loop Heat Pipe Rejection System: Seven Years in Space

NASA Technical Reports Server (NTRS)

Rodriguez, Jose I.; Na-Nakornpanom, Arthur

2012-01-01

The Tropospheric Emission Spectrometer (TES) instrument heat rejection system has been operating in space for nearly 8 years since launched on NASA's EOS Aura Spacecraft. The instrument is an infrared imaging fourier transform spectrometer with spectral coverage of 3.2 to 15.4 microns. The loop heat pipe (LHP) based heat rejection system manages all of the instrument components waste heat including the two mechanical cryocoolers and their drive electronics. Five propylene LHPs collect and transport the instrument waste heat to the near room temperature nadir viewing radiators. During the early months of the mission, ice contamination of the cryogenic surfaces including the focal planes led to increased cryocooler loads and the need for periodic decontamination cycles. Focal plane decontamination cycles require power cycling both cryocoolers which also requires the two cryocooler LHPs to turn off and on during each cycle. To date, the cryocooler LHPs have undergone 24 start-ups in orbit successfully. This paper reports on the TES cryocooler loop heat pipe based heat rejection system performance. After a brief overview of the instrument thermal design, the paper presents detailed data on the highly successful space operation of the loop heat pipes since instrument turn-on in 2004. The data shows that the steady-state and transient operation of the LHPs has not changed since 2004 and shows consistent and predictable performance. The LHP based heat rejection system has provided a nearly constant heat rejection heat sink for all of its equipment which has led to exceptional overall instrument performance with world class science.

Formation of dioxins during the combustion of newspapers in the presence of sodium chloride and poly(vinyl chloride).

PubMed

Yasuhara, A; Katami, T; Okuda, T; Ohno, N; Shibamoto, T

2001-04-01

Exhaust gases from the combustion of newspaper alone, from branches of London plane tree alone, and from newspapers mixed with sodium chloride (NaCl), polyethylene, or poly(vinyl chloride) (PVC) were collected. The samples were analyzed for dioxins by gas chromatography/mass spectrometry. Total amounts of dioxins found in the samples were 0.186 ng/g from newspapers alone, 1.42 ng/g from the branches of London plane, 102 ng/g from newspapers impregnated with sodium chloride (CI wt % = 3.1), 101 ng/g from newspapers impregnated with sodium chloride mixed with PVC (Cl wt % = 2.6), and 146 ng/g from newspapers mixed with PVC (Cl wt % = 5.1). Samples with a higher chloride content produced more dioxins, and there is a clear correlation between dioxin formation and chloride content. The amount of dioxins formed in the samples according to the number of chlorides was Cl5 > Cl4 > Cl6 > Cl7 > Cl8 in PCDD isomers and Cl4 > Cl5 > Cl6 > Cl7 > Cl8 in PCDF isomers, except in the case of newspapers alone. Benzofurans composed 78-92% of the total dioxins formed in the exhaust gases. The higher the number of the chlorides, the lower the production of benzofuran observed. NaCl vaporized at the temperature of the flame used for combustion of the samples (760-1080 degrees C). The results indicate that NaCl and PVC contribute significantly to dioxin formation from waste materials combusted in incinerators.

Relationship between mechanical properties and crystal structure in cocrystals and salt of paracetamol.

PubMed

Ahmed, Hamzah; Shimpi, Manishkumar R; Velaga, Sitaram P

2017-01-01

Objectives were to study mechanical properties of various solid forms of paracetamol and relate to their crystal structures. Paracetamol form I (PRA), its cocrystals with oxalic acid (PRA-OXA) and 4,4-bipyridine (PRA-BPY) and hydrochloride salt (PRA-HCL) were selected. Cocrystals and salt were scaled-up using rational crystallization methods. The resulting materials were subjected to different solid-state characterizations. The powders were sieved and 90-360 µm sieve fraction was considered. These powders were examined by scanning electron microscopy (SEM) and densities were determined. Tablets were made at applied pressures of 35-180 MPa under controlled conditions and the tablet height, diameter and hardness were measured. Tensile strength and porosity of the tablets were estimated using well known models. Crystal structures of these systems were visualized and slip planes were identified. Cocrystal and salt of PRA were physically pure. Sieved powders had comparable morphologies and particle size. The apparent and theoretical densities of powders were similar, but no clear trends were observed. The tensile strengths of these compacts were increased with increasing pressure whereas tabletability decreased in the order oxalic acid > PRA-HCL ≈ PRA-OXA > BPY > PRA-BPY. Tablet tensile strength decreases exponentially with increasing porosity with the exception of PRY-BPY and BPY. Slip plane prediction based on attachment energies may not be independently considered. However, it was possible to explain the improved mechanical properties of powders based on the crystal structure. Cocrystallization and salt formation have introduced structural features that are responsible for improved tableting properties of PRA.

Short-Term Results in Evaluating a Gingiva-Adhesive Hydrophobic-Chlorhexidine-Gel for Chronic Periodontitis.

PubMed

Sarbu, Ciprian; Rusu, Darian; Călniceanu, Horia; Kasaj, Adrian; Petrutiu, Stefan Adrian; Roman, Alexandra; Soancă, Andrada; PicoȘ, Alina; Stratul, Stefan Ioan; Jentsch, Holger

2014-01-01

Oral mucosa and interproximal spaces of the teeth could favor the colonization of periodontopathogenic bacteria, which could be targeted by chemical antiplaque agents such as chlorhexidine, present in different oral hygiene products, thus improving the control of biofilm growth and delaying microbial accumulation. The study aimed to evaluate whether the use of a hydrophobic gel with good gingival adhesion for 14 days after the scaling and root planing of patients with chronic periodontitis would improve the treatment outcome, when compared with the use of a regular hydrophyllic gel. Patients with moderate disease were included in two study groups. At baseline and 3 months after the treatment the following parameters were recorded: pocket depth, Approximal Plaque Index, Modified Gingival Index, Simplified Oral Hygiene Index, bleeding on probing. Patients received scaling and root planing in two sessions at 24 hours interval. After the treatment, patients in the test group applied the hydrophobic adhesive chlorhexidine gel once a day, every other day, while in the control group the gel was used twice daily. Both treatments resulted in significant improvement in all clinical indices, except Approximal Plaque Index, which deteriorated significantly in both groups. Three months after mechanical treatment, the mean probing depth changed in the test group from 4.16±0.45 mm to 2.80±0.42 mm, and in the control group from 4.16±0.30 to 2.69±0.19. Both adjunctive anti-infective therapies induced clinical improvement 3 months from baseline. The differences between the two treatments were not statistically significant.

Investigation on the properties of omnidirectional photonic band gaps in two-dimensional plasma photonic crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hai-Feng, E-mail: hanlor@163.com; Nanjing Artillery Academy, Nanjing 211132; Liu, Shao-Bin

2016-01-15

The properties of omnidirectional photonic band gaps (OBGs) in two-dimensional plasma photonic crystals (2D PPCs) are theoretically investigated by the modified plane wave expansion method. In the simulation, we consider the off-plane incident wave vector. The configuration of 2D PPCs is the triangular lattices filled with the nonmagnetized plasma cylinders in the homogeneous and isotropic dielectric background. The calculated results show that the proposed 2D PPCs possess a flatbands region and the OBGs. Compared with the OBGs in the conventional 2D dielectric-air PCs, it can be obtained more easily and enlarged in the 2D PPCs with a similar structure. Themore » effects of configurational parameters of the PPCs on the OBGs also are studied. The simulated results demonstrate that the locations of OBGs can be tuned easily by manipulating those parameters except for changing plasma collision frequency. The achieved OBGs can be enlarged by optimizations. The OBGs of two novel configurations of PPCs with different cross sections are computed for a comparison. Both configurations have the advantages of obtaining the larger OBGs compared with the conventional configuration, since the symmetry of 2D PPCs is broken by different sizes of periodically inserted plasma cylinders or connected by the embedded plasma cylinders with thin veins. The analysis of the results shows that the bandwidths of OBGs can be tuned by changing geometric and physical parameters of such two PPCs structures. The theoretical results may open a new scope for designing the omnidirectional reflectors or mirrors based on the 2D PPCs.« less

Self Healing Fibre-reinforced Polymer Composites: an Overview

NASA Astrophysics Data System (ADS)

Bond, Ian P.; Trask, Richard S.; Williams, Hugo R.; Williams, Gareth J.

Lightweight, high-strength, high-stiffness fibre-reinforced polymer composite materials are leading contenders as component materials to improve the efficiency and sustainability of many forms of transport. For example, their widespread use is critical to the success of advanced engineering applications, such as the Boeing 787 and Airbus A380. Such materials typically comprise complex architectures of fine fibrous reinforcement e.g. carbon or glass, dispersed within a bulk polymer matrix, e.g. epoxy. This can provide exceptionally strong, stiff, and lightweight materials which are inherently anisotropic, as the fibres are usually arranged at a multitude of predetermined angles within discrete stacked 2D layers. The direction orthogonal to the 2D layers is usually without reinforcement to avoid compromising in-plane performance, which results in a vulnerability to damage in the polymer matrix caused by out-of-plane loading, i.e. impact. Their inability to plastically deform leaves only energy absorption via damage creation. This damage often manifests itself internally within the material as intra-ply matrix cracks and inter-ply delaminations, and can thus be difficult to detect visually. Since relatively minor damage can lead to a significant reduction in strength, stiffness and stability, there has been some reticence by designers for their use in safety critical applications, and the adoption of a `no growth' approach (i.e. damage propagation from a defect constitutes failure) is now the mindset of the composites industry. This has led to excessively heavy components, shackling of innovative design, and a need for frequent inspection during service (Richardson 1996; Abrate 1998).

Advances in 2D boron nitride nanostructures: nanosheets, nanoribbons, nanomeshes, and hybrids with graphene.

PubMed

Lin, Yi; Connell, John W

2012-11-21

The recent surge in graphene research has stimulated interest in the investigation of various 2-dimensional (2D) nanomaterials. Among these materials, the 2D boron nitride (BN) nanostructures are in a unique position. This is because they are the isoelectric analogs to graphene structures and share very similar structural characteristics and many physical properties except for the large band gap. The main forms of the 2D BN nanostructures include nanosheets (BNNSs), nanoribbons (BNNRs), and nanomeshes (BNNMs). BNNRs are essentially BNNSs with narrow widths in which the edge effects become significant; BNNMs are also variations of BNNSs, which are supported on certain metal substrates where strong interactions and the lattice mismatch between the substrate and the nanosheet result in periodic shallow regions on the nanosheet surface. Recently, the hybrids of 2D BN nanostructures with graphene, in the form of either in-plane hybrids or inter-plane heterolayers, have also drawn much attention. In particular, the BNNS-graphene heterolayer architectures are finding important electronic applications as BNNSs may serve as excellent dielectric substrates or separation layers for graphene electronic devices. In this article, we first discuss the structural basics, spectroscopic signatures, and physical properties of the 2D BN nanostructures. Then, various top-down and bottom-up preparation methodologies are reviewed in detail. Several sections are dedicated to the preparation of BNNRs, BNNMs, and BNNS-graphene hybrids, respectively. Following some more discussions on the applications of these unique materials, the article is concluded with a summary and perspectives of this exciting new field.

Craniofacial changes in Icelandic children between 6 and 16 years of age - a longitudinal study.

PubMed

Thordarson, Arni; Johannsdottir, Berglind; Magnusson, Thordur Eydal

2006-04-01

The aim of the present study was to describe the craniofacial changes between 6 and 16 years of age in a sample of Icelandic children. Complete sets of lateral cephalometric radiographs were available from 95 males and 87 females. Twenty-two reference points were digitized and processed by standard methods, using the Dentofacial Planner computer software program. Thirty-three angular and linear variables were calculated, including: basal sagittal and vertical measurements, facial ratio, and dental, cranial base and mandibular measurements. For the angular measurements, gender differences were not statistically different for any of the measurements, in either age group, except for the variable s-n-na, which was larger in the 16-year-old boys (P < or = 0.001). Linear variables were consistently larger in the boys compared with the girls at both age levels. During the observation period mandibular prognathism increased but the basal sagittal jaw relationship, the jaw angle, the mandibular plane angle and cranial base flexure (n-s-ba) decreased in both genders (P < or = 0.001). Maxillary prognathism increased only in the boys from 6 to 16 years. Inclination of the lower incisors and all the cranial base dimensions increased in both genders during the observation period. When the Icelandic sample was compared with a similar Norwegian sample, small differences could be noted in the maxillary prognathism, mandibular plane angle and in the inclination of the maxilla. Larger differences were identified in the inclination of the lower incisors. These findings could be used as normative cephalometric standards for 6- and 16-year-old Icelandic children.

Evaluation of ambient dose equivalent rates influenced by vertical and horizontal distribution of radioactive cesium in soil in Fukushima Prefecture.

PubMed

Malins, Alex; Kurikami, Hiroshi; Nakama, Shigeo; Saito, Tatsuo; Okumura, Masahiko; Machida, Masahiko; Kitamura, Akihiro

2016-01-01

The air dose rate in an environment contaminated with (134)Cs and (137)Cs depends on the amount, depth profile and horizontal distribution of these contaminants within the ground. This paper introduces and verifies a tool that models these variables and calculates ambient dose equivalent rates at 1 m above the ground. Good correlation is found between predicted dose rates and dose rates measured with survey meters in Fukushima Prefecture in areas contaminated with radiocesium from the Fukushima Dai-ichi Nuclear Power Plant accident. This finding is insensitive to the choice for modeling the activity depth distribution in the ground using activity measurements of collected soil layers, or by using exponential and hyperbolic secant fits to the measurement data. Better predictions are obtained by modeling the horizontal distribution of radioactive cesium across an area if multiple soil samples are available, as opposed to assuming a spatially homogeneous contamination distribution. Reductions seen in air dose rates above flat, undisturbed fields in Fukushima Prefecture are consistent with decrement by radioactive decay and downward migration of cesium into soil. Analysis of remediation strategies for farmland soils confirmed that topsoil removal and interchanging a topsoil layer with a subsoil layer result in similar reductions in the air dose rate. These two strategies are more effective than reverse tillage to invert and mix the topsoil. Copyright © 2015 Elsevier Ltd. All rights reserved.

New Research by CCD Scanning for Comets and Asteroids

NASA Technical Reports Server (NTRS)

Gehrels, Tom; McMillan, Robert S.

1997-01-01

The purpose of Spacewatch is to explore the various populations of small objects within the solar system. Spacewatch provides data for studies of comets and asteroids, finds potential targets for space missions, and provides information on the environmental problem of possible impacts. Moving objects are discovered by scanning the sky with charge-coupled devices (CCDs) on the 0.9-meter Spacewatch Telescope of the University of Arizona on Kitt Peak. Each Spacewatch scan consists of three drift scan passes over an area of sky using a CCD filtered to a bandpass of 0.5-1.0 microns (approximately V+R+I with peak sensitivity at 0.7 micron). The effective exposure time for each pass is 143 seconds multiplied by the secant of the declination. We have been finding some 30,000 new asteroids per year and applying their statistics to the study of the collisional history of the solar system. As of the end of the observing run of Nov. 1997, Spacewatch had found a total of 153 Near-Earth Asteroids (NEAs) and 8 new comets since the project began in the 1980s, and had recovered one lost comet. The total number of NEAs found by Spacewatch big enough to be hazardous if they were to impact the Earth is 36. Spacewatch is also efficient in recovery of known comets and has detected and reported positions for more than 137,000 asteroids, mostly new ones in the main belt, including more than 16,000 asteroids designated by the Minor Planet Center (MPC).

Individual phase constitutive properties of a TRIP-assisted QP980 steel from a combined synchrotron X-ray diffraction and crystal plasticity approach

DOE PAGES

Hu, Xiao Hua; Sun, X.; Hector, Jr., L. G.; ...

2017-04-21

Here, microstructure-based constitutive models for multiphase steels require accurate constitutive properties of the individual phases for component forming and performance simulations. We address this requirement with a combined experimental/theoretical methodology which determines the critical resolved shear stresses and hardening parameters of the constituent phases in QP980, a TRIP assisted steel subject to a two-step quenching and partitioning heat treatment. High energy X-Ray diffraction (HEXRD) from a synchrotron source provided the average lattice strains of the ferrite, martensite, and austenite phases from the measured volume during in situ tensile deformation. The HEXRD data was then input to a computationally efficient, elastic-plasticmore » self-consistent (EPSC) crystal plasticity model which estimated the constitutive parameters of different slip systems for the three phases via a trial-and-error approach. The EPSC-estimated parameters are then input to a finite element crystal plasticity (CPFE) model representing the QP980 tensile sample. The predicted lattice strains and global stress versus strain curves are found to be 8% lower that the EPSC model predicted values and from the HEXRD measurements, respectively. This discrepancy, which is attributed to the stiff secant assumption in the EPSC formulation, is resolved with a second step in which CPFE is used to iteratively refine the EPSC-estimated parameters. Remarkably close agreement is obtained between the theoretically-predicted and experimentally derived flow curve for the QP980 material.« less

Constitutive models for a poly(e-caprolactone) scaffold.

PubMed

Quinn, T P; Oreskovic, T L; McCowan, C N; Washburn, N R

2004-01-01

We investigate material models for a porous, polymeric scaffold used for bone. The material was made by co-extruding poly(e-caprolactone) (PCL), a biodegradable polyester, and poly(ethylene oxide) (PEO). The water soluble PEO was removed resulting in a porous scaffold. The stress-strain curve in compression was fit with a phenomenological model in hyperbolic form. This material model will be useful for designers for quasi-static analysis as it provides a simple form that can easily be used in finite element models. The ASTM D-1621 standard recommends using a secant modulus based on 10% strain. The resulting modulus has a smaller scatter in its value compared to the coefficients of the hyperbolic model, and it is therefore easier to compare material processing differences and ensure quality of the scaffold. A third material model was constructed from images of the microstructure. Each pixel of the micrographs was represented with a brick finite element and assigned the Young's modulus of bulk PCL or a value of 0 for a pore. A compressive strain was imposed on the model and the resulting stresses were calculated. The elastic constants of the scaffold were then computed using Hooke's law for a linear-elastic isotropic material. The model was able to predict the small strain Young's modulus measured in the experiments to within one standard deviation. Thus, by knowing the microstructure of the scaffold, its bulk properties can be predicted from the material properties of the constituents.

Long-Term Mechanical Behavior of Nano Silica Sol Grouting

PubMed Central

Zhang, Nong; Zhang, Chenghao; Qian, Deyu; Han, Changliang; Yang, Sen

2018-01-01

The longevity of grouting has a significant effect on the safe and sustainable operation of many engineering projects. A 500-day experiment was carried out to study the long-term mechanical behavior of nano silica sol grouting. The nano silica sol was activated with different proportions of a NaCl catalyst and cured under fluctuating temperature and humidity conditions. The mechanical parameters of the grout samples were tested using an electrohydraulic uniaxial compression tester and an improved Vicat instrument. Scanning electron microscope, X-ray diffraction, and ultrasonic velocity tests were carried out to analyze the strength change micro-mechanism. Tests showed that as the catalyst dosage in the grout mix is decreased, the curves on the graphs showing changes in the weight and geometric parameters of the samples over time could be divided into three stages, a shrinkage stage, a stable stage, and a second shrinkage stage. The catalyst improved the stability of the samples and reduced moisture loss. Temperature rise was also a driving force for moisture loss. Uniaxial compressive stress-strain curves for all of the samples were elastoplastic. The curves for uniaxial compression strength and secant modulus plotted against time could be divided into three stages. Sample brittleness increased with time and the brittleness index increased with higher catalyst dosages in the latter part of the curing time. Plastic strength-time curves exhibit allometric scaling. Curing conditions mainly affect the compactness, and then affect the strength. PMID:29337897

Individual phase constitutive properties of a TRIP-assisted QP980 steel from a combined synchrotron X-ray diffraction and crystal plasticity approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, X. H.; Sun, X.; Hector, L. G.

2017-06-01

Microstructure-based constitutive models for multiphase steels require accurate constitutive properties of the individual phases for component forming and performance simulations. We address this requirement with a combined experimental/theoretical methodology which determines the critical resolved shear stresses and hardening parameters of the constituent phases in QP980, a TRIP assisted steel subject to a two-step quenching and partitioning heat treatment. High energy X-Ray diffraction (HEXRD) from a synchrotron source provided the average lattice strains of the ferrite, martensite, and austenite phases from the measured volume during in situ tensile deformation. The HEXRD data was then input to a computationally efficient, elastic-plastic self-consistentmore » (EPSC) crystal plasticity model which estimated the constitutive parameters of different slip systems for the three phases via a trial-and-error approach. The EPSC-estimated parameters are then input to a finite element crystal plasticity (CPFE) model representing the QP980 tensile sample. The predicted lattice strains and global stress versus strain curves are found to be 8% lower that the EPSC model predicted values and from the HEXRD measurements, respectively. This discrepancy, which is attributed to the stiff secant assumption in the EPSC formulation, is resolved with a second step in which CPFE is used to iteratively refine the EPSC-estimated parameters. Remarkably close agreement is obtained between the theoretically-predicted and experimentally derived flow curve for the QP980 material.« less

Ultrasound-Guided Out-of-Plane vs. In-Plane Interscalene Catheters: A Randomized, Prospective Study.

PubMed

Schwenk, Eric S; Gandhi, Kishor; Baratta, Jaime L; Torjman, Marc; Epstein, Richard H; Chung, Jaeyoon; Vaghari, Benjamin A; Beausang, David; Bojaxhi, Elird; Grady, Bernadette

2015-12-01

Continuous interscalene blocks provide excellent analgesia after shoulder surgery. Although the safety of the ultrasound-guided in-plane approach has been touted, technical and patient factors can limit this approach. We developed a caudad-to-cephalad out-of-plane approach and hypothesized that it would decrease pain ratings due to better catheter alignment with the brachial plexus compared to the in-plane technique in a randomized, controlled study. To compare an out-of-plane interscalene catheter technique to the in-plane technique in a randomized clinical trial. Eighty-four patients undergoing open shoulder surgery were randomized to either the in-plane or out-of-plane ultrasound-guided continuous interscalene technique. The primary outcome was VAS pain rating at 24 hours. Secondary outcomes included pain ratings in the recovery room and at 48 hours, morphine consumption, the incidence of catheter dislodgments, procedure time, and block difficulty. Procedural data and all pain ratings were collected by blinded observers. There were no differences in the primary outcome of median VAS pain rating at 24 hours between the out-of-plane and in-plane groups (1.50; IQR, [0 - 4.38] vs. 1.25; IQR, [0 - 3.75]; P = 0.57). There were also no differences, respectively, between out-of-plane and in-plane median PACU pain ratings (1.0; IQR, [0 - 3.5] vs. 0.25; IQR, [0 - 2.5]; P = 0.08) and median 48-hour pain ratings (1.25; IQR, [1.25 - 2.63] vs. 0.50; IQR, [0 - 1.88]; P = 0.30). There were no differences in any other secondary endpoint. Our out-of-plane technique did not provide superior analgesia to the in-plane technique. It did not increase the number of complications. Our technique is an acceptable alternative in situations where the in-plane technique is difficult to perform.

Morphologic Variability of the Shoulder between the Populations of North American and East Asian.

PubMed

Cabezas, Andres F; Krebes, Kristi; Hussey, Michael M; Santoni, Brandon G; Kim, Hyuong Sik; Frankle, Mark A; Oh, Joo Han

2016-09-01

The aim of this study was to determine if there were significant differences in glenohumeral joint morphology between North American and East Asian populations that may influence sizing and selection of shoulder arthroplasty systems. Computed tomography reconstructions of 92 North American and 58 East Asian patients were used to perform 3-dimensional measurements. The proximal humeral position was normalized in all patients by aligning it with the scapular plane utilizing anatomic landmarks. Measurements were performed on the humerus and scapula and included coronal and axial humeral head radius, humeral neck shaft and articular arc angles, glenoid height and width, and critical shoulder angle. Glenohumeral relationships were also measured and included lateral distance to the greater tuberosity and acromion, abduction lever arm, and acromial index. Parametric and nonparametric statistical analyses were used to compare population metrics. East Asian glenohumeral measurements were significantly smaller for all linear metrics (p < 0.05), with the exception of acromial length, which was greater than in the North American cohort (p < 0.001). The increase in acromial length affected all measurements involving the acromion including abduction lever arms. No difference was found between the neck shaft and articular angular measurements. The East Asian population exhibited smaller shoulder morphometrics than their North American cohort, with the exception of an extended acromial overhang. The morphologic data can provide some additional factors to consider when choosing an optimal shoulder implant for the East Asian population, in addition to creating future designs that may better accommodate this population.

A New Selective Area Lateral Epitaxy Approach for Depositing a-Plane GaN over r-Plane Sapphire

NASA Astrophysics Data System (ADS)

Chen, Changqing; Zhang, Jianping; Yang, Jinwei; Adivarahan, Vinod; Rai, Shiva; Wu, Shuai; Wang, Hongmei; Sun, Wenhong; Su, Ming; Gong, Zheng; Kuokstis, Edmundas; Gaevski, Mikhail; Khan, Muhammad Asif

2003-07-01

We report a new epitaxy procedure for growing extremely low defect density a-plane GaN films over r-plane sapphire. By combining selective area growth through a SiO2 mask opening to produce high height to width aspect ratio a-plane GaN pillars and lateral epitaxy from their c-plane facets, we obtained fully coalesced a-plane GaN films. The excellent structural, optical and electrical characteristics of these selective area lateral epitaxy (SALE) deposited films make them ideal for high efficiency III-N electronic and optoelectronic devices.

A cephalometric study to determine the plane of occlusion in completely edentulous patients.

PubMed

Hindocha, Amit D; Vartak, Vikas N; Bhandari, Aruna J; Dudani, Mohit T

2013-01-01

Determination of the plane of occlusion in completely edentulous patients with the help of the ala-tragus line (Camper's plane) may be questioned. An attempt to devise an alternative method to determine the orientation of the plane of occlusion was made. Cephalometric analysis was used to identify whether a correlation exists between the plane of occlusion of dentulous Indian individuals and other stable cranial landmarks. A negative correlation was found to exist between the occlusal Plane-FH plane angle and the porion-nasion-anterior nasal spine (PoNANS) angle. From the derived mathematical correlation, it was concluded that the angulation of the occlusal plane in completely edentulous subjects may be determined by taking a cephalogram at the diagnostic stage. Further, the clinical applicability of the derived mathematical formula (while determining the plane of occlusion) was tested on completely edentulous patients.

Influence of the narrow {111} planes on axial and planar ion channeling.

PubMed

Motapothula, M; Dang, Z Y; Venkatesan, T; Breese, M B H; Rana, M A; Osman, A

2012-05-11

We report channeling patterns where clearly resolved effects of the narrow {111} planes are observed in axial and planar alignments for 2 MeV protons passing through a 55 nm [001] silicon membrane. At certain axes, such as <213> and <314>, the offset in atomic rows forming the narrow {111} planes results in shielding from the large potential at the wide {111} planes, producing a region of shallow, asymmetric potential from which axial channeling patterns have no plane of symmetry. At small tilts from such axes, different behavior is observed from the wide and narrow {111} planes. At planar alignment, distinctive channeling effects due to the narrow planes are observed. As a consequence of the shallow potential well at the narrow planes, incident protons suffer dechanneled trajectories which are excluded from channeling within the wide planes, resulting in an anomalously large scattered beam at {111} alignment.

Broken chiral symmetry on a null plane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beane, Silas R., E-mail: silas@physics.unh.edu

2013-10-15

On a null-plane (light-front), all effects of spontaneous chiral symmetry breaking are contained in the three Hamiltonians (dynamical Poincaré generators), while the vacuum state is a chiral invariant. This property is used to give a general proof of Goldstone’s theorem on a null-plane. Focusing on null-plane QCD with N degenerate flavors of light quarks, the chiral-symmetry breaking Hamiltonians are obtained, and the role of vacuum condensates is clarified. In particular, the null-plane Gell-Mann–Oakes–Renner formula is derived, and a general prescription is given for mapping all chiral-symmetry breaking QCD condensates to chiral-symmetry conserving null-plane QCD condensates. The utility of the null-planemore » description lies in the operator algebra that mixes the null-plane Hamiltonians and the chiral symmetry charges. It is demonstrated that in a certain non-trivial limit, the null-plane operator algebra reduces to the symmetry group SU(2N) of the constituent quark model. -- Highlights: •A proof (the first) of Goldstone’s theorem on a null-plane is given. •The puzzle of chiral-symmetry breaking condensates on a null-plane is solved. •The emergence of spin-flavor symmetries in null-plane QCD is demonstrated.« less

Deviation of landmarks in accordance with methods of establishing reference planes in three-dimensional facial CT evaluation.

PubMed

Yoon, Kaeng Won; Yoon, Suk-Ja; Kang, Byung-Cheol; Kim, Young-Hee; Kook, Min Suk; Lee, Jae-Seo; Palomo, Juan Martin

2014-09-01

This study aimed to investigate the deviation of landmarks from horizontal or midsagittal reference planes according to the methods of establishing reference planes. Computed tomography (CT) scans of 18 patients who received orthodontic and orthognathic surgical treatment were reviewed. Each CT scan was reconstructed by three methods for establishing three orthogonal reference planes (namely, the horizontal, midsagittal, and coronal reference planes). The horizontal (bilateral porions and bilateral orbitales) and midsagittal (crista galli, nasion, prechiasmatic point, opisthion, and anterior nasal spine) landmarks were identified on each CT scan. Vertical deviation of the horizontal landmarks and horizontal deviation of the midsagittal landmarks were measured. The porion and orbitale, which were not involved in establishing the horizontal reference plane, were found to deviate vertically from the horizontal reference plane in the three methods. The midsagittal landmarks, which were not used for the midsagittal reference plane, deviated horizontally from the midsagittal reference plane in the three methods. In a three-dimensional facial analysis, the vertical and horizontal deviations of the landmarks from the horizontal and midsagittal reference planes could vary depending on the methods of establishing reference planes.

The lateral plane delivers higher dose than the frontal plane in biplane cardiac catheterization systems.

PubMed

Aldoss, Osamah; Patel, Sonali; Harris, Kyle; Divekar, Abhay

2015-06-01

The objective of the study is to compare radiation dose between the frontal and lateral planes in a biplane cardiac catheterization laboratory. Tube angulation progressively increases patient and operator radiation dose in single-plane cardiac catheterization laboratories. This retrospective study captured biplane radiation dose in a pediatric cardiac catheterization laboratory between April 2010 and January 2014. Raw and time-indexed fluoroscopic, cineangiographic and total (fluoroscopic + cineangiographic) air kerma (AK, mGy) and kerma area product (PKA, µGym(2)/Kg) for each plane were compared. Data for 716 patients were analyzed: 408 (56.98 %) were male, the median age was 4.86 years, and the median weight was 17.35 kg. Although median beam-on time (minutes) was 4.2 times greater in the frontal plane, there was no difference in raw median total PKA between the two planes. However, when indexed to beam-on time, the lateral plane had a higher median-indexed fluoroscopic (0.75 vs. 1.70), cineangiographic (16.03 vs. 24.92), and total (1.43 vs. 5.15) PKA (p < 0.0001). The median time-indexed total PKA in the lateral plane is 3.6 times the frontal plane. This is the first report showing that the lateral plane delivers a higher dose than the frontal plane per unit time. Operators should consciously reduce the lateral plane beam-on time and incorporate this practice in radiation reduction protocols.

Planer orientation of the bilateral semicircular canals in dizzy patients.

PubMed

Aoki, Sachiko; Takei, Yasuhiko; Suzuki, Kazufumi; Masukawa, Ai; Arai, Yasuko

2012-10-01

Recent development of 3-dimensional analysis of eye movement enabled to detect the eye rotation axis, which is used to determine the responsible semicircular canal(s) in dizzy patients. Therefore, the knowledge of anatomical orientation of bilateral semicircular canals is essential, as all 6 canals influence the eye movements. Employing the new head coordinate system suitable for MR imaging, we calculated the angles of semicircular canal planes of both ears in 11 dizzy patients who had normal caloric response in both ears. The angles between adjacent canal pairs were nearly perpendicular in both ears. The angle between the posterior canal planes and head sagittal plane was 51° and significantly larger the angle between the anterior canal planes and head sagittal plane, which was 35°. The angle between the horizontal canal plane and head sagittal plane was almost orthogonal. Pairs of contralateral synergistic canal planes were not parallel, forming 10° between right and left horizontal canal planes, 17° between right anterior and left posterior canal planes and 19° between the right posterior and left anterior canal planes. Our measurement of the angles of adjacent canal pairs and the angle between each semicircular canal and head sagittal plane coincided with those of previous reports obtained from CT images and skull specimens. However, the angles between contralateral synergistic canal planes were more parallel than those of previous reports. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Agreement Between Visual Assessment and 2-Dimensional Analysis During Jump Landing Among Healthy Female Athletes.

PubMed

Rabin, Alon; Einstein, Ofira; Kozol, Zvi

2018-04-01

  Altered movement patterns, including increased frontal-plane knee movement and decreased sagittal-plane hip and knee movement, have been associated with several knee disorders. Nevertheless, the ability of clinicians to visually detect such altered movement patterns during high-speed athletic tasks is relatively unknown.   To explore the association between visual assessment and 2-dimensional (2D) analysis of frontal-plane knee movement and sagittal-plane hip and knee movement during a jump-landing task among healthy female athletes.   Cross-sectional study.   Gymnasiums of participating volleyball teams.   A total of 39 healthy female volleyball players (age = 21.0 ± 5.2 years, height = 172.0 ± 8.6 cm, mass = 64.2 ± 7.2 kg) from Divisions I and II of the Israeli Volleyball Association.   Frontal-plane knee movement and sagittal-plane hip and knee movement during jump landing were visually rated as good, moderate, or poor based on previously established criteria. Frontal-plane knee excursion and sagittal-plane hip and knee excursions were measured using free motion-analysis software and compared among athletes with different visual ratings of the corresponding movements.   Participants with different visual ratings of frontal-plane knee movement displayed differences in 2D frontal-plane knee excursion ( P < .01), whereas participants with different visual ratings of sagittal-plane hip and knee movement displayed differences in 2D sagittal-plane hip and knee excursions ( P < .01).   Visual ratings of frontal-plane knee movement and sagittal-plane hip and knee movement were associated with differences in the corresponding 2D hip and knee excursions. Visual rating of these movements may serve as an initial screening tool for detecting altered movement patterns during jump landings.

A study of parallelism of the occlusal plane and ala-tragus line.

PubMed

Sadr, Katayoun; Sadr, Makan

2009-01-01

Orientation of the occlusal plane is one of the most important clinical procedures in prostho-dontic rehabilitation of edentulous patients. The aim of this study was to define the best posterior reference point of ala-tragus line for orientation of occlusal plane for complete denture fabrication. Fifty-three dental students (27 females and 26 males) with complete natural dentition and Angel's Class I occlusal relationship were selected. The subjects were photographed in natural head position while clenching on a Fox plane. After tracing the photographs, the angles between the following lines were measured: the occlusal plane (Fox plane) and the superior border of ala-tragus, the occlusal plane (Fox plane) and the middle of ala-tragus as well as the occlusal plane (Fox plane) and the inferior border of ala-tragus. Descriptive statistics, one sample t-test and independent t-test were used. P value less than 0.05 was considered significant. There was no parallelism between the occlusal plane and ala-tragus line with three different posterior ends and one sample t-test showed that the angles between them were significantly different from zero (p<0.05). However, the supe-rior border of ala-tragus line had the lowest mean angle, 1.80° (3.12) and was almost parallel to the occlusal plane. The superior border of the tragus is suggested as the posterior reference for ala-tragus line.

An optimized microstructure to minimizing in-plane and through-plane pressure drops of fibrous materials: Counter-intuitive reduction of gas diffusion layer permeability with porosity

NASA Astrophysics Data System (ADS)

Sadeghifar, Hamidreza

2018-05-01

The present study experimentally investigates the realistic functionality of in-plane and through-plane pressure drops of layered fibrous media with porosity, fiber diameter, fiber spacing, fiber-fiber angles and fiber-flow angles. The study also reveals that pressure drop may increase with porosity and fiber diameter under specific circumstances. This counter-intuitive point narrows down the validity range of widely-used permeability-porosity-diameter models or correlations. It is found that, for fibrous materials, the most important parameter that impacts the in-plane pressure drop is not their porosities but the number of fibers extended in the flow direction. It is also concluded that in-plane pressure drop is highly dependent upon the flow direction (fiber-flow angles), especially at lower porosities. Contrary to in-plane pressure drop, through-plane pressure drop is a weak function of fiber-fiber angles but is strongly impacted by fiber spacing, especially at lower porosities. At a given porosity, low through-plane pressure drops occur if fiber spacing does not change practically from one layer to another. Through-plane pressure drop also, insignificantly, increases with the intersecting angles between fibers. An optimized microstructure of fibrous media resulting in minimal in-plane and through-plane pressure drops is also offered for the first time in this work.

Method for selectively orienting induced fractures in subterranean earth formations

DOEpatents

Shuck, Lowell Z.

1977-02-01

The orientation of hydraulically-induced fractures in relatively deep subterranean earth formations is normally confined to vertical projections along a plane parallel to the maximum naturally occurring (tectonic) compressive stress field. It was found that this plane of maximum compressive stress may be negated and, in effect, re-oriented in a plane projecting generally orthogonal to the original tectonic stress plane by injecting liquid at a sufficiently high pressure into a wellbore fracture oriented in a plane parallel to the plane of tectonic stress for the purpose of stressing the surrounding earth formation in a plane generally orthogonal to the plane of tectonic stress. With the plane of maximum compressive stress re-oriented due to the presence of the induced compressive stress, liquid under pressure is injected into a second wellbore disposed within the zone influenced by the induced compressive stress but at a location in the earth formation laterally spaced from the fracture in the first wellbore for effecting a fracture in the second wellbore along a plane generally orthogonal to the fracture in the first wellbore.

Single crystalline Co3O4 nanocrystals exposed with different crystal planes for Li-O2 batteries.

PubMed

Su, Dawei; Dou, Shixue; Wang, Guoxiu

2014-08-29

Single crystalline Co3O4 nanocrystals exposed with different crystal planes were synthesised, including cubic Co3O4 nanocrystals enclosed by {100} crystal planes, pseudo octahedral Co3O4 enclosed by {100} and {110} crystal planes, Co3O4 nanosheets exposed by {110} crystal planes, hexagonal Co3O4 nanoplatelets exposed with {111} crystal planes, and Co3O4 nanolaminar exposed with {112} crystal planes. Well single crystalline features of these Co3O4 nanocrystals were confirmed by FESEM and HRTEM analyses. The electrochemical performance for Li-O2 batteries shows that Co3O4 nanocrystals can significantly reduce the discharge-charge over-potential via the effect on the oxygen evolution reaction (OER). From the comparison on their catalytic performances, we found that the essential factor to promote the oxygen evolution reactions is the surface crystal planes of Co3O4 nanocrystals, namely, crystal planes-dependent process. The correlation between different Co3O4 crystal planes and their effect on reducing charge-discharge over-potential was established: {100} < {110} < {112} < {111}.

49 CFR 572.10 - Limbs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... planes parallel to its midsagittal plane (knee pivot centerline perpendicular to the midsagittal plane...) Impact the knee with the test probe moving horizontally and parallel to the midsagittal plane at the...

Identifying logical planes formed of compute nodes of a subcommunicator in a parallel computer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Kristan D.; Faraj, Daniel

In a parallel computer, a plurality of logical planes formed of compute nodes of a subcommunicator may be identified by: for each compute node of the subcommunicator and for a number of dimensions beginning with a first dimension: establishing, by a plane building node, in a positive direction of the first dimension, all logical planes that include the plane building node and compute nodes of the subcommunicator in a positive direction of a second dimension, where the second dimension is orthogonal to the first dimension; and establishing, by the plane building node, in a negative direction of the first dimension,more » all logical planes that include the plane building node and compute nodes of the subcommunicator in the positive direction of the second dimension.« less

Gated strip proportional detector

DOEpatents

Morris, C.L.; Idzorek, G.C.; Atencio, L.G.

1985-02-19

A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10/sup 6/. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

Gated strip proportional detector

DOEpatents

Morris, Christopher L.; Idzorek, George C.; Atencio, Leroy G.

1987-01-01

A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10.sup.6. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

Interest in the glenoid hull method for analyzing humeral subluxation in primary glenohumeral osteoarthritis.

PubMed

Bouacida, Soufyane; Gauci, Marc-Olivier; Coulet, Bertrand; Lazerges, Cyril; Cyteval, Catherine; Boileau, Pascal; Chammas, Michel

2017-07-01

Posterior humeral subluxation is the main cause of failure of total shoulder arthroplasty. We aimed to compare humeral head subluxation in various reference planes and to search for a correlation with retroversion, inclination, and glenoid wear. We included 109 computed tomography scans of primary glenohumeral osteoarthritis and 97 of shoulder problems unrelated to shoulder osteoarthritis (controls); all computed tomography scans were reconstructed in the anatomic scapular plane and the glenoid hull plane that we defined. In both planes, we measured retroversion, inclination, glenohumeral offset (Walch index), and scapulohumeral offset. Retroversion in the scapular plane (Friedman method) was lower than that in the glenoid hull plane for controls and for arthritic shoulders. The threshold of scapulohumeral subluxation was 60% and 65% in the scapular plane and glenoid hull plane, respectively. The mean upward inclination was lower in the scapular plane (Churchill method) than in the glenoid hull plane (Maurer method). In the glenoid hull plane, 35% of type A2 glenoids showed glenohumeral offset greater than 75%, with mean retroversion of 25.6° ± 6° as compared with 7.5° ± 7.2° for the "centered" type A2 glenoids (P < .0001) and an upward inclination of -1.4° ± 8° and 6.3° ± 7° (P = .03), respectively. The correlation between retroversion and scapulohumeral offset was r = 0.64 in the glenoid hull plane and r = 0.59 in the scapular plane (P < .05). Measurement in the glenoid hull plane may be more accurate than in the scapular plane. Thus, the glenoid hull method allows for better understanding type B3 of the modified Walch classification. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Effects of sires with different weight gain potentials and varying planes of nutrition on growth of growing-finishing pigs.

PubMed

Ha, Duck-Min; Jung, Dae-Yun; Park, Man Jong; Park, Byung-Chul; Lee, C Young

2014-01-01

The present study was performed to investigate the effects of two groups of sires with 'medium' and 'high' weight gain potentials (M-sires and H-sires, respectively) on growth of their progenies on varying planes of nutrition during the growing-finishing period. The ADG of the M-sires' progeny was greater (P < 0.05) than that of the H-sires' progeny (0.51 vs. 0.47 kg) during a 26- to 29-d early grower phase beginning from 55 d of age, but the opposite was true (0.66 vs. 0.72 kg) during the latter grower phase. Overall grower-phase ADG was greatest on the high plane of nutrition (H plane) followed by the medium (M) and low (L) planes (0.65, 0.61, and 0.51 kg, respectively; P < 0.05) in the M-sires' progeny, whereas in the H-sires' progeny, ADG was greater on the H and M planes vs. L plane (0.63, 0.62, and 0.54 kg, respectively). The ADG of pigs on the M or H plane during the grower phase and switched to the H plane thereafter (M-to-H or H-to-H planes) was greater than that of pigs on the L-to-L planes (0.99 vs. 0.78 kg) during the early finisher phase in the M-sires' progeny (P < 0.01). However, in the H-sires' progeny, ADG of pigs on the L-to-L planes did not differ from that of pigs on the M-to-M or H-to-M planes (0.94 vs. 0.96 kg). Results suggest that the H-to-H or H-to-M planes and M-to-M or M-to-L planes are optimal for maximal growth of the M- and H-sires' progenies, respectively.

Pulmonary intersegmental planes: imaging appearance and possible reasons leading to their visualization.

PubMed

Zuo, Yi-Zhi; Liu, Chao; Liu, Shu-Wei

2013-04-01

To describe the normal imaging appearance of pulmonary intersegmental planes on thoracic computed tomographic (CT) scans and determine the possible reasons related to their visualization in terms of aging and anatomy. The study was approved by the internal ethics review board. Informed consent was obtained. A retrospective review was undertaken of 104 thoracic multidetector CT scans of an older group (>65 years) and younger group (<55 years). The number, location, and appearance rate of intersegmental planes were assessed. Group comparisons were made, and linear regression analysis was used to assess relationships between age and visualization of intersegmental planes. Thirty lung samples (10 × 10 × 10 mm(3)) from autopsy were scanned by using micro-CT. Thicknesses of intersegmental planes were measured. Significant differences of the thickness between visible and invisible intersegmental planes were assessed with the independent t test. In five fetal specimens (17-21 weeks in gestational age), 7.0-T magnetic resonance (MR) imaging was performed to determine the congenital difference of thickness of intersegmental planes. Within the right lung, appearance rates of visible intersegmental planes were 71.2% at S1-S3, 54.8% at S4-S5, and 70.2% at S7-S10. Within the left lung, appearance rates of visible intersegmental planes were 39.4% at S1+2 to S3, 64.4% at S4-S5, 18.3% at S7-S8, and 89.4% at S7-S10. Appearance rates of visible intersegmental planes on thoracic CT scans were not significantly different (P ≥ .38) between younger and older groups. Mean thicknesses of visible and invisible intersegmental planes were 681.3 μm ± 75.3 (standard deviation) and 221.7 μm ± 54.1, respectively. Visible intersegmental planes were significantly thicker than invisible intersegmental planes (P < .05). Visible intersegmental planes were also seen on fetal lung 7.0-T MR images. The thickness of pulmonary intersegmental planes and variation of intersegmental veins were closely related to visualization of intersegmental planes on thoracic CT scans. Aging was excluded as the possible reason. RSNA, 2013

Lower extremity energy absorption and biomechanics during landing, part II: frontal-plane energy analyses and interplanar relationships.

PubMed

Norcross, Marc F; Lewek, Michael D; Padua, Darin A; Shultz, Sandra J; Weinhold, Paul S; Blackburn, J Troy

2013-01-01

Greater sagittal-plane energy absorption (EA) during the initial impact phase (INI) of landing is consistent with sagittal-plane biomechanics that likely increase anterior cruciate ligament (ACL) loading, but it does not appear to influence frontal-plane biomechanics. We do not know whether frontal-plane INI EA is related to high-risk frontal-plane biomechanics. To compare biomechanics among INI EA groups, determine if women are represented more in the high group, and evaluate interplanar INI EA relationships. Descriptive laboratory study. Research laboratory. Participants included 82 (41 men, 41 women; age = 21.0 ± 2.4 years, height = 1.74 ± 0.10 m, mass = 70.3 ± 16.1 kg) healthy, physically active volunteers. We assessed landing biomechanics with an electromagnetic motion-capture system and force plate. We calculated frontal- and sagittal-plane total, hip, knee, and ankle INI EA. Total frontal-plane INI EA was used to create high, moderate, and low tertiles. Frontal-plane knee and hip kinematics, peak vertical and posterior ground reaction forces, and peak internal knee-varus moment (pKVM) were identified and compared across groups using 1-way analyses of variance. We used a χ (2) analysis to evaluate male and female allocation to INI EA groups. We used simple, bivariate Pearson product moment correlations to assess interplanar INI EA relationships. The high-INI EA group exhibited greater knee valgus at ground contact, hip adduction at pKVM, and peak hip adduction than the low-INI EA group (P < .05) and greater peak knee valgus, pKVM, and knee valgus at pKVM than the moderate- (P < .05) and low- (P < .05) INI EA groups. Women were more likely than men to be in the high-INI EA group (χ(2) = 4.909, P = .03). Sagittal-plane knee and frontal-plane hip INI EA (r = 0.301, P = .006) and sagittal-plane and frontal-plane ankle INI EA were associated (r = 0.224, P = .04). No other interplanar INI EA relationships were found (P > .05). Greater frontal-plane INI EA was associated with less favorable frontal-plane biomechanics that likely result in greater ACL loading. Women were more likely than men to use greater frontal-plane INI EA. The magnitudes of sagittal- and frontal-plane INI EA were largely independent.

INTERIOR OF SECOND FLOOR BRIDGE BETWEEN PLANING MILL AND CAR ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR OF SECOND FLOOR BRIDGE BETWEEN PLANING MILL AND CAR MACHINE SHOP, LOOKING SOUTH TOWARD PLANING MILL. - Southern Pacific, Sacramento Shops, Planing Mill, 111 I Street, Sacramento, Sacramento County, CA

Identifying a largest logical plane from a plurality of logical planes formed of compute nodes of a subcommunicator in a parallel computer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Kristan D.; Faraj, Daniel A.

In a parallel computer, a largest logical plane from a plurality of logical planes formed of compute nodes of a subcommunicator may be identified by: identifying, by each compute node of the subcommunicator, all logical planes that include the compute node; calculating, by each compute node for each identified logical plane that includes the compute node, an area of the identified logical plane; initiating, by a root node of the subcommunicator, a gather operation; receiving, by the root node from each compute node of the subcommunicator, each node's calculated areas as contribution data to the gather operation; and identifying, bymore » the root node in dependence upon the received calculated areas, a logical plane of the subcommunicator having the greatest area.« less

A Study of Parallelism of the Occlusal Plane and Ala-Tragus Line

PubMed Central

Sadr, Katayoun; Sadr, Makan

2009-01-01

Background and aims Orientation of the occlusal plane is one of the most important clinical procedures in prostho-dontic rehabilitation of edentulous patients. The aim of this study was to define the best posterior reference point of ala-tragus line for orientation of occlusal plane for complete denture fabrication. Materials and methods Fifty-three dental students (27 females and 26 males) with complete natural dentition and Angel’s Class I occlusal relationship were selected. The subjects were photographed in natural head position while clenching on a Fox plane. After tracing the photographs, the angles between the following lines were measured: the occlusal plane (Fox plane) and the superior border of ala-tragus, the occlusal plane (Fox plane) and the middle of ala-tragus as well as the occlusal plane (Fox plane) and the inferior border of ala-tragus. Descriptive statistics, one sample t-test and independent t-test were used. P value less than 0.05 was considered significant. Results There was no parallelism between the occlusal plane and ala-tragus line with three different posterior ends and one sample t-test showed that the angles between them were significantly different from zero (p<0.05). However, the supe-rior border of ala-tragus line had the lowest mean angle, 1.80° (3.12) and was almost parallel to the occlusal plane. Conclusion The superior border of the tragus is suggested as the posterior reference for ala-tragus line. PMID:23230496

Quantum mechanics on the h-deformed quantum plane

NASA Astrophysics Data System (ADS)

Cho, Sunggoo

1999-03-01

We find the covariant deformed Heisenberg algebra and the Laplace-Beltrami operator on the extended h-deformed quantum plane and solve the Schrödinger equations explicitly for some physical systems on the quantum plane. In the commutative limit the behaviour of a quantum particle on the quantum plane becomes that of the quantum particle on the Poincaré half-plane, a surface of constant negative Gaussian curvature. We show that the bound state energy spectra for particles under specific potentials depend explicitly on the deformation parameter h. Moreover, it is shown that bound states can survive on the quantum plane in a limiting case where bound states on the Poincaré half-plane disappear.

14 CFR 23.509 - Towing loads.

Code of Federal Regulations, 2010 CFR

2010-01-01

... on the landing gear but near the plane of symmetry of the airplane, the drag and side tow load....Aft. Swiveled aft 0.3W 78 Forward.Aft. Swiveled 45° from forward 0.15W 910 Forward, in plane of wheel.Aft, in plane of wheel. Swiveled 45° from aft 0.15W 1112 Forward, in plane of wheel.Aft, in plane of...

Use of hydrogen etching to remove existing dislocations in GaN epitaxial layers

NASA Astrophysics Data System (ADS)

Yeh, Yen-Hsien; Chu, Chung-Ming; Wu, Yin-Hao; Hsu, Ying-Chia; Yu, Tzu-Yi; Lee, Wei-I.

2015-08-01

In this paper, based on the anisotropic nature of hydrogen (H2) etching on GaN, we describe a new approach to the removal of threading dislocations in GaN layers. The top surfaces of c-plane (Ga-face) and a-plane GaNs are considered stable in H2; therefore, H2 etches only crystal imperfections such as dislocation and basal plane stacking fault (BSF) sites. We used H2 to etch undoped c-plane GaN, n-type c-plane GaN, a-plane GaN, and an InGaN/GaN multiple quantum well structure. Several examinations were performed, indicating deep cavities on the c-plane GaN samples after H2 etching; furthermore, gorge-like grooves were observed on the a-plane GaN samples. The deep cavities on the c-plane GaN were considered the etched dislocation sites, and the gorge-like grooves on the a-plane GaN were considered the etched BSF sites. Photoluminescence measurements were performed and the results indicated that the H2-etched samples demonstrate superior optoelectronic properties, probably because of the elimination of dislocations.

Comparison of 2D Finite Element Modeling Assumptions with Results From 3D Analysis for Composite Skin-Stiffener Debonding

NASA Technical Reports Server (NTRS)

Krueger, Ronald; Paris, Isbelle L.; OBrien, T. Kevin; Minguet, Pierre J.

2004-01-01

The influence of two-dimensional finite element modeling assumptions on the debonding prediction for skin-stiffener specimens was investigated. Geometrically nonlinear finite element analyses using two-dimensional plane-stress and plane-strain elements as well as three different generalized plane strain type approaches were performed. The computed skin and flange strains, transverse tensile stresses and energy release rates were compared to results obtained from three-dimensional simulations. The study showed that for strains and energy release rate computations the generalized plane strain assumptions yielded results closest to the full three-dimensional analysis. For computed transverse tensile stresses the plane stress assumption gave the best agreement. Based on this study it is recommended that results from plane stress and plane strain models be used as upper and lower bounds. The results from generalized plane strain models fall between the results obtained from plane stress and plane strain models. Two-dimensional models may also be used to qualitatively evaluate the stress distribution in a ply and the variation of energy release rates and mixed mode ratios with delamination length. For more accurate predictions, however, a three-dimensional analysis is required.

Understanding the anisotropic strain effects on lithium diffusion in graphite anodes: A first-principles study

NASA Astrophysics Data System (ADS)

Ji, Xiang; Wang, Yang; Zhang, Junqian

2018-06-01

The lithium diffusion in graphite anode, which is the most widely used commercial electrode material today, affects the charge/discharge performance of lithium-ion batteries. In this study, the anisotropic strain effects on lithium diffusion in graphite anodes are systematically investigated using first-principles calculations based on density functional theory (DFT) with van der Waals corrections. It is found that the effects of external applied strains along various directions of LixC6 (i.e., perpendicular or parallel to the basal planes of the graphite host) on lithium diffusivity are different. Along the direction perpendicular to the graphite planes, the tensile strain facilitates in-plane Li diffusion by reducing the energy barrier, and the compressive strain hinders in-plane Li diffusion by raising the energy barrier. In contrast, the in-plane biaxial tensile strain (parallel to the graphite planes) hinders in-plane Li diffusion, and the in-plane biaxial compressive strain facilitates in-plane Li diffusion. Furthermore, both in-plane and transverse shear strains slightly influence Li diffusion in graphite anodes. A discussion is presented to explain the anisotropic strain dependence of lithium diffusion. This research provides data for the continuum modelling of the electrodes in the lithium-ion batteries.

Influence of 2D Finite Element Modeling Assumptions on Debonding Prediction for Composite Skin-stiffener Specimens Subjected to Tension and Bending

NASA Technical Reports Server (NTRS)

Krueger, Ronald; Minguet, Pierre J.; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

The influence of two-dimensional finite element modeling assumptions on the debonding prediction for skin-stiffener specimens was investigated. Geometrically nonlinear finite element analyses using two-dimensional plane-stress and plane strain elements as well as three different generalized plane strain type approaches were performed. The computed deflections, skin and flange strains, transverse tensile stresses and energy release rates were compared to results obtained from three-dimensional simulations. The study showed that for strains and energy release rate computations the generalized plane strain assumptions yielded results closest to the full three-dimensional analysis. For computed transverse tensile stresses the plane stress assumption gave the best agreement. Based on this study it is recommended that results from plane stress and plane strain models be used as upper and lower bounds. The results from generalized plane strain models fall between the results obtained from plane stress and plane strain models. Two-dimensional models may also be used to qualitatively evaluate the stress distribution in a ply and the variation of energy release rates and mixed mode ratios with lamination length. For more accurate predictions, however, a three-dimensional analysis is required.

Single Crystalline Co3O4 Nanocrystals Exposed with Different Crystal Planes for Li-O2 Batteries

PubMed Central

Su, Dawei; Dou, Shixue; Wang, Guoxiu

2014-01-01

Single crystalline Co3O4 nanocrystals exposed with different crystal planes were synthesised, including cubic Co3O4 nanocrystals enclosed by {100} crystal planes, pseudo octahedral Co3O4 enclosed by {100} and {110} crystal planes, Co3O4 nanosheets exposed by {110} crystal planes, hexagonal Co3O4 nanoplatelets exposed with {111} crystal planes, and Co3O4 nanolaminar exposed with {112} crystal planes. Well single crystalline features of these Co3O4 nanocrystals were confirmed by FESEM and HRTEM analyses. The electrochemical performance for Li-O2 batteries shows that Co3O4 nanocrystals can significantly reduce the discharge-charge over-potential via the effect on the oxygen evolution reaction (OER). From the comparison on their catalytic performances, we found that the essential factor to promote the oxygen evolution reactions is the surface crystal planes of Co3O4 nanocrystals, namely, crystal planes-dependent process. The correlation between different Co3O4 crystal planes and their effect on reducing charge-discharge over-potential was established: {100} < {110} < {112} < {111}. PMID:25169737

Influence of rotating in-plane field on vertical Bloch lines in the walls of second kind of dumbbell domains

NASA Astrophysics Data System (ADS)

Sun, H. Y.; Hu, H. N.; Sun, Y. P.; Nie, X. F.

2004-08-01

Influence of rotating in-plane field on vertical Bloch lines in the walls of second kind of dumbbell domains (IIDs) was investigated, and a critical in-plane field range [ Hip1, Hip2] of which vertical-Bloch lines (VBLs) annihilated in IIDs is found under rotating in-plane field ( Hip1 is the maximal critical in-plane-field of which hard domains remain stable, Hip2 is the minimal critical in-plane-field of which all of the hard domains convert to soft bubbles (SBs, without VBLs)). It shows that the in-plane field range [ Hip1, Hip2] changes with the change of the rotating angle Δ ϕ. Hip1 maintains stable, while Hip2 decreases with the decreasing of rotating angle Δ ϕ. Comparing it with the spontaneous shrinking experiment of IIDs under both bias field and in-plane field, we presume that under the application of in-plane field there exists a direction along which the VBLs in the domain walls annihilate most easily, and it is in the direction that domain walls are perpendicular to the in-plane field.

Baryons and their Effects on Planes of Satellites Around Milky Way-Mass Galaxies

NASA Astrophysics Data System (ADS)

Ahmed, Sheehan H.

2017-01-01

Both the Milky Way and Andromeda have thin, coherently rotating planes of satellites. In this study I try to find similar satellite planes around four different Milky Way-mass simulations, each run both as dark matter-only and with baryons included. In all halos I am able to identify a planar configuration that significantly maximizes the number of satellites that are members of a plane. The member satellites that make up this maximum plane are consistently different between the dark matter-only and baryonic versions of the same run. In the baryonic runs, satellites are more likely to be destroyed through interactions with the disk, and substructure tends to infall later. Hence, studying satellite planes in dark matter-only simulations is misleading, because they will be composed of different satellite members than those that would exist if baryons were included. Additionally, baryonic runs tend to have less radially concentrated satellite distributions. Since all planes pass through the center of the galaxy, it is much harder to create a plane containing a large number of satellites from a random distribution if the satellites have a low radial concentration. Andromeda’s low radial satellite concentration is possibly a key reason behind why the plane in Andromeda is highly significant. Despite this, when co-rotation is considered, none of the satellite planes identified for the simulated galaxies are as statistically significant as the observed planes around the Milky Way and Andromeda. I will then show that co-rotation in our satellite planes can be attributed to how the satellites are accreted through filaments from the cosmic web. When two sets of opposing filaments contribute, coherent planes are more likely to form, when there are no well-defined filaments, there is a lack of coherent satellite rotation.

Polarized radio emission from the edge-on spiral galaxies NGC 891 and NGC 4565

NASA Technical Reports Server (NTRS)

Sukumar, S.; Allen, R. J.

1991-01-01

Results are presented, at a resolution of 20 arcsec, of observations of the distribution of radio continuum intensity and linear polarization with the VLA in two nearby edge-on spiral galaxies, NGC 891 and NGC 4565, at 6 and 20 cm, respectively. A unified model is presented to account for the main features of the radio polarization in these two galaxies. The model geometry is determined from recent observations of face-on galaxies where the polarized emission is found to be strongest in the dark inter-arm and outer parts of the disks. A substantial Z-thickness is ascribed to this polarized emission. It is shown that the exceptionally strong wavelength dependence of this type of Faraday depolarization can result in edge-on galaxies becoming rapidly 'Faraday thick' at decimeter wavelengths, thereby obliterating the polarization from regions on the dark side of the disk. The degree of polarization observed in both galaxies increases strongly with increasing Z-distance from the plane.

Structural and elastic properties of AIBIIIC 2 VI semiconductors

NASA Astrophysics Data System (ADS)

Kumar, V.; Singh, Bhanu P.

2018-01-01

The plane wave pseudo-potential method within density functional theory has been used to calculate the structural and elastic properties of AIBIIIC 2 VI semiconductors. The electronic band structure, density of states, lattice constants (a and c), internal parameter (u), tetragonal distortion (η), energy gap (Eg), and bond lengths of the A-C (dAC) and B-C (dBC) bonds in AIBIIIC 2 VI semiconductors have been calculated. The values of elastic constants (Cij), bulk modulus (B), shear modulus (G), Young's modulus (Y), Poisson's ratio (υ), Zener anisotropy factor (A), Debye temperature (ϴD) and G/B ratio have also been calculated. The values of all 15 parameters of CuTlS2 and CuTlSe2 compounds, and 8 parameters of 20 compounds of AIBIIIC 2 VI family, except AgInS2 and AgInSe2, have been calculated for the first time. Reasonably good agreement has been obtained between the calculated, reported and available experimental values.

The Dizzying Depths of the Cylindrical Mirror

NASA Astrophysics Data System (ADS)

DeWeerd, Alan J.; Hill, S. Eric

2005-02-01

A typical introduction to geometrical optics treats plane and spherical mirrors. At first glance, it may be surprising that texts seldom mention the cylindrical mirror, except for the occasional reference to use in fun houses and to viewing anamorphic art.1,2 However, even a cursory treatment reveals its complexity. Holzberlein used an extended object to qualitatively illustrate that images are produced both before and behind a concave cylindrical mirror.3 He also speculated on how this extreme astigmatism results in an observer's dizziness. By considering a simple point object, we make a more detailed analysis of the cylindrical mirror and the dizziness it induces. First, we illustrate how rays from a point object reflect to form not one point image but two line images. Next, we describe how an observer perceives a likeness of the object. Finally, we suggest how confusing depth cues induce dizziness. Although we focus on the concave cylindrical mirror, the discussion is easy to generalize to the convex cylindrical mirror.

On the method of lumens

PubMed Central

Shera, Christopher A.

2014-01-01

Parent and Allen [(2007). J. Acoust. Soc. Am. 122, 918–931] introduced the “method of lumens” to compute the plane-wave reflectance in a duct terminated with a nonuniform impedance. The method involves splitting the duct into multiple, fictitious subducts (lumens), solving for the reflectance in each subduct, and then combining the results. The method of lumens has considerable intuitive appeal and is easily implemented in the time domain. Previously applied only in a complex acoustical setting where proper evaluation is difficult (i.e., in a model of the ear canal and tympanic membrane), the method is tested here by using it to compute the reflectance from an area constriction in an infinite lossless duct considered in the long-wavelength limit. Neither the original formulation of the method—shown here to violate energy conservation except when the termination impedance is uniform—nor a reformulation consistent with basic physical constraints yields the correct solution to this textbook problem in acoustics. The results are generalized and the nature of the errors illuminated. PMID:25480060

Gas adsorption/absorption heat switch, phase 1

NASA Technical Reports Server (NTRS)

Chan, C. K.

1987-01-01

The service life and/or reliability of far-infrared sensors on surveillance satellites is presently limited by the cryocooler. The life and/or reliability, however, can be extended by using redundant cryocoolers. To reduce parasitic heat leak, each stage of the inactive redundant cryocooler must be thermally isolated from the optical system, while each stage of the active cryocooler must be thermally connected to the system. The thermal break or the thermal contact can be controlled by heat switches. Among different physical mechanisms for heat switching, mechanically activated heat switches tend to have low reliability and, furthermore, require a large contact force. Magnetoresistive heat switches are, except at very low temperatures, of very low efficiency. Heat switches operated by the heat pipe principle usually require a long response time. A sealed gas gap heat switch operated by an adsorption pump has no mechanical motion and should provide the reliability and long lifetime required in long-term space missions. Another potential application of a heat switch is the thermal isolation of the optical plane during decontamination.

Distribution of chaos and periodic spikes in a three-cell population model of cancer. Auto-organization of oscillatory phases in parameter planes

NASA Astrophysics Data System (ADS)

Gallas, Michelle R.; Gallas, Marcia R.; Gallas, Jason A. C.

2014-10-01

We study complex oscillations generated by the de Pillis-Radunskaya model of cancer growth, a model including interactions between tumor cells, healthy cells, and activated immune system cells. We report a wide-ranging systematic numerical classification of the oscillatory states and of their relative abundance. The dynamical states of the cell populations are characterized here by two independent and complementary types of stability diagrams: Lyapunov and isospike diagrams. The model is found to display stability phases organized regularly in old and new ways: Apart from the familiar spirals of stability, it displays exceptionally long zig-zag networks and intermixed cascades of two- and three-doubling flanked stability islands previously detected only in feedback systems with delay. In addition, we also characterize the interplay between continuous spike-adding and spike-doubling mechanisms responsible for the unbounded complexification of periodic wave patterns. This article is dedicated to Prof. Hans Jürgen Herrmann on the occasion of his 60th birthday.

On the Preferred Active Sites of Promoted MoS 2 for Hydrodesulfurization with Minimal Organonitrogen Inhibition

DOE PAGES

Rangarajan, Srinivas; Mavrikakis, Manos

2016-12-14

Hydrodesulfurization is a process to produce ultralow-sulfur diesel fuel. Although promoted molybdenum sulfide (MoS 2) catalysts have been used industrially for several decades, the active site requirements for selective hydrodesulfurization of organosulfur compounds with minimal inhibition by organonitrogen constituents of a real gasoil feed has not been resolved. By using molecular binding energy descriptors derived from plane wave density functional theory calculations for comparative adsorption of organosulfur and organonitrogen compounds, we analyzed more than 20 potential sites on unpromoted and Ni- and Co-promoted MoS 2. We also found that hydrogen sulfide and ammonia are simple descriptors of adsorption of stericallymore » unhindered organosulfur and organonitrogen compounds such as dibenzothiophene and acridine, respectively. Further, organonitrogen compounds in gasoil bind more strongly than organosulfur compounds on all sites except on sites with exposed metal atoms on the corner and sulfur edges of promoted MoS 2. Consequently, these sites are proposed as required for maximum-hydrodesulfurization minimum-inhibition catalysis.« less

Planes, Trains, and Automobiles: Perspectives on CAR T Cells and Other Cellular Therapies for Hematologic Malignancies.

PubMed

Gill, Saar

2016-08-01

Hematologic oncologists now have at their disposal (or a referral away) a myriad of new options to get from point A (a patient with relapsed or poor-risk disease) to point B (potential tumor eradication and long-term disease-free survival). In this perspective piece, we discuss the putative mechanisms of action and the relative strengths and weaknesses of currently available cellular therapy approaches. Notably, while many of these approaches have been published in high impact journals, with the exception of allogeneic stem cell transplantation and of checkpoint inhibitors (PD1/PDL1 or CTLA4 blockade), the published clinical trials have mostly been early phase, uncontrolled studies. Therefore, many of the new cellular therapy approaches have yet to demonstrate incontrovertible evidence of enhanced overall survival compared with controls. Nonetheless, the science behind these is sure to advance our understanding of cancer immunology and ultimately to bring us closer to our goal of curing cancer.

Supersonic dynamic stability characteristics of the test technique demonstrator NASP configuration

NASA Technical Reports Server (NTRS)

Dress, David A.; Boyden, Richmond P.; Cruz, Christopher I.

1992-01-01

Wind tunnel tests of a National Aero-Space Plane (NASP) configuration were conducted in both test sections of the Langley Unitary Plan Wind Tunnel. The model used is a Langley designed blended body NASP configuration. Dynamic stability characteristics were measured on this configuration at Mach numbers of 2.0, 2.5, 3.5, and 4.5. In addition to tests of the baseline configuration, component buildup tests were conducted. The test results show that the baseline configuration generally has positive damping about all three axes with only isolated exceptions. In addition, there was generally good agreement between the in-pulse dynamic parameters and the corresponding static data which were measured during another series of tests in the Unitary Plan Wind Tunnel. Also included are comparisons of the experimental damping parameters with results from the engineering predictive code APAS (Aerodynamic Preliminary Analysis System). These comparisons show good agreement at low angles of attack; however, the comparisons are generally not as good at the higher angles of attack.

[Magnetic resonance for the study of osteosarcoma].

PubMed

Spina, V; Romagnoli, R; Manfrini, M; Cerofolini, E; Capanna, R; Gaiani, L; Calandra Buonaura, P; Picci, P; Campanacci, M

1991-01-01

The authors report their experience with MR imaging in the study of osteosarcoma. Two main elements were evaluated: signal characteristics and loco-regional staging. Seventy-one patients were studied: 65 of them had central long-bone osteosarcoma, and 6 had telangiectatic long-bone osteosarcoma. T1- and T2-weighted spin-echo sequences were employed and all cases were scanned on 3 planes (sagittal, coronal, and axial). In 28 patients MR imaging was performed both before and after preoperative chemotherapy. The obtained data were compared to surgical and pathological findings. With the exception of the typical signal patterns of quite-osteoblastic osteosarcoma (which presents with low signal on both T1- and T2-weighted sequences), no particular signal features were observed which could help distinguish the different types of osteosarcoma. MR imaging is the method of choice in loco-regional staging for, in our series, it allowed a rational and adequate surgical planning. For this purpose, at least a longitudinal T1- and an axial T2-weighted images are required.

Self-assembling layers created by membrane proteins on gold.

PubMed

Shah, D S; Thomas, M B; Phillips, S; Cisneros, D A; Le Brun, A P; Holt, S A; Lakey, J H

2007-06-01

Membrane systems are based on several types of organization. First, amphiphilic lipids are able to create monolayer and bilayer structures which may be flat, vesicular or micellar. Into these structures membrane proteins can be inserted which use the membrane to provide signals for lateral and orientational organization. Furthermore, the proteins are the product of highly specific self-assembly otherwise known as folding, which mostly places individual atoms at precise places in three dimensions. These structures all have dimensions in the nanoscale, except for the size of membrane planes which may extend for millimetres in large liposomes or centimetres on planar surfaces such as monolayers at the air/water interface. Membrane systems can be assembled on to surfaces to create supported bilayers and these have uses in biosensors and in electrical measurements using modified ion channels. The supported systems also allow for measurements using spectroscopy, surface plasmon resonance and atomic force microscopy. By combining the roles of lipids and proteins, highly ordered and specific structures can be self-assembled in aqueous solution at the nanoscale.

Quasi-normal modes of holographic system with Weyl correction and momentum dissipation

NASA Astrophysics Data System (ADS)

Wu, Jian-Pin; Liu, Peng

2018-05-01

We study the charge response in complex frequency plane and the quasi-normal modes (QNMs) of the boundary quantum field theory with momentum dissipation dual to a probe generalized Maxwell system with Weyl correction. When the strength of the momentum dissipation α ˆ is small, the pole structure of the conductivity is similar to the case without the momentum dissipation. The qualitative correspondence between the poles of the real part of the conductivity of the original theory and the ones of its electromagnetic (EM) dual theory approximately holds when γ → - γ with γ being the Weyl coupling parameter. While the strong momentum dissipation alters the pole structure such that most of the poles locate at the purely imaginary axis. At this moment, the correspondence between the poles of the original theory and its EM dual one is violated when γ → - γ. In addition, for the dominant pole, the EM duality almost holds when γ → - γ for all α ˆ except for a small region of α ˆ .

Effects of gravity on meiosis, fertilization and early embryogenesis in Caenorhabditis elegans

NASA Astrophysics Data System (ADS)

Sasagawa, Y.; Saito, Y.; Shimizu, M.; Ishioka, N.; Yamashita, M.; Takahashi, H.; Higashitani, A.

The embryonic development of the nematode Caenorhabditis elegans was examined under different gravitational conditions. The first cleavage plane in the 1-cell embryo was slid to some extent by re-orientation of liquid culture vessel, but the pattern and timing of cleavages were not affected. Under 100G of hypergravity condition with swing-centrifuge, the number of eggs laid from an adult hermaphrodite decreased and their hatching rate was drastically reduced. On the other hand, the embryonic development after fertilization normally occurred and grew to adulthood at more than 100G of hypergravity. When the adult hermaphrodites cultured under 100G of hypergravity transferred to a ground condition (1G), the newly fertilized embryos normally developed and their hatching rate was fully recovered. These results indicated that the reproductive process except spermatogenesis, oogenesis and embryogenesis after fertilization is impaired under 100G of hypergravity condition, and the effect is transient. Namely, the fertilization process including meiotic divisions I and II is sensitive to hypergravity in the nematode C. elegans.

Poly[[di-μ-aqua-(μ-4-formyl-2-meth­oxy­phenol­ato)disodium] 4-formyl-2-meth­oxy­phenolate

PubMed Central

Asghar, Muhammad Nadeem; Şahin, Onur; Arshad, Muhammad Nadeem; Mazhar, Uzma; Khan, Islam Ullah; Büyükgüngör, Orhan

2010-01-01

In the title coordination polymer, {[Na2(C8H7O3)(H2O)4](C8H7O3)}n, all the non-H atoms except the water O atoms lie on a crystallographic mirror plane. One sodium cation is bonded to four water O atoms and one vanillinate O atom in a distorted square-based pyramidal arrangement; the other Na+ ion is six-coordinated by four water O atoms and two vanillinate O atoms in an irregular geometry. One of the vanillinate anions is directly bonded to two sodium ions, whilst the other only inter­acts with the polymeric network by way of hydrogen bonds. In the crystal, a two-dimensional polymeric array is formed; this is reinforced by O—H⋯O hydrogen bonds, which generate R 2 1(6) and R 2 2(20) loops. PMID:21579628

Aeroacoustic wind-tunnel tests of a light twin-boom general-aviation airplane with free or shrouded-pusher propellers. [in the Langley full-scale tunnel

NASA Technical Reports Server (NTRS)

Mclemore, H. C.; Pegg, R. J.

1980-01-01

Tests were conducted in the Langley full-scale tunnel to determine the aerodynamic performance and acoustic characteristics of four different pusher-propeller configurations on a twin boom, general aviation airplane. The propellers included a 2-blade free propeller, two 3-blade shrouded propellers, and a 5-blade shrouded propeller. The tests were conducted for a range of airplane angles of attack from about 0 deg to 16 deg for test speeds from 0 to about 36 m/sec and for a range of propeller blade angles and rotation speeds. The free propeller provided the best aerodynamic propulsive performance. For forward flight conditions, the free propeller noise levels were lower than those of the shrouded propellers. In the static conditions the free propeller noise levels were as low as those for the shrouded propellers, except for the propeller in-plane noise where the shrouded propeller noise levels were lower.

Energy levels of a hydrogenic impurity in a parabolic quantum well with a magnetic field

NASA Astrophysics Data System (ADS)

Zang, J. X.; Rustgi, M. L.

1993-07-01

In this paper, we present a calculation of the energy levels of a hydrogenic impurity (or a hydrogenic atom) at the bottom of a one-dimensional parabolic quantum well with a magnetic field normal to the plane of the well. The finite-basis-set variational method is used to calculate the ground state and the excited states with major quantum number less than or equal to 3. The limit of small radial distance and the limit of great radial distance are considered to choose a set of proper basis functions. The results in the limit that the parabolic parameter α=0 are compared with the data of Rösner et al. [J. Phys. B 17, 29 (1984)]. The comparison shows that the present calculation is quite accurate. It is found that the energy levels increase with increasing parabolic parameter α and increase with increasing normalized magnetic-field strength γ except those levels with magnetic quantum number m<0 at small γ.

A two-dimensional model of a directional microphone: calculation of the normal force and moment on the diaphragm.

PubMed

Homentcovschi, Dorel; Aubrey, Matthew J; Miles, Ronald N

2006-02-01

It has been shown that the parasitoid fly Ormia Ochracea exhibits exceptional sound localization ability achieved through the mechanical coupling of its eardrums [R. N. Miles et al., J. Acoust. Soc. Am. 98, 3059-3070 (1995)]. Based on this biological system a new directional microphone has been designed, having as a basic element a special diaphragm undergoing a rocking motion. This paper considers a 2D model of the microphone in which the diaphragm is considered as a 2D plate having slits on the sides. The slits lead to a backing volume limited by an infinite rigid wall parallel to the diaphragm in its neutral position. The reflection and diffraction of an incoming plane wave by this system are studied to determine the resultant force and resultant moment of pressure upon the diaphragm. The results show that such a microphone will be driven better in the case of narrow slits and deep cavities.

Spatial variations in fault friction related to lithology from rupture and afterslip of the 2014 South Napa, California, earthquake

USGS Publications Warehouse

Michael Floyd,; Richard Walters,; John Elliot,; Funning, Gareth J.; Svarc, Jerry L.; Murray, Jessica R.; Andy Hooper,; Yngvar Larsen,; Petar Marinkovic,; Bürgmann, Roland; Johanson, Ingrid; Tim Wright,

2016-01-01

Following earthquakes, faults are often observed to continue slipping aseismically. It has been proposed that this afterslip occurs on parts of the fault with rate-strengthening friction that are stressed by the mainshock, but our understanding has been limited by a lack of immediate, high-resolution observations. Here we show that the behavior of afterslip following the 2014 South Napa earthquake varied over distances of only a few kilometers. This variability cannot be explained by coseismic stress changes alone. We present daily positions from continuous and survey GPS sites that we re-measured within 12 hours of the mainshock, and surface displacements from the new Sentinel-1 radar mission. This unique geodetic data set constrains the distribution and evolution of coseismic and postseismic fault slip with exceptional resolution in space and time. We suggest that the observed heterogeneity in behavior is caused by lithological controls on the frictional properties of the fault plane.

Structural and characteristic variation of anodic oxide on pure Ti with anodization duration

NASA Astrophysics Data System (ADS)

Mizukoshi, Yoshiteru; Ohtsu, Naofhumi; Masahashi, Naoya

2013-10-01

Change in the structural and characteristic of the anodic oxide on pure Ti with the duration of anodization time was investigated. With the progress of the anodization, the phase of the formed TiO2 successively changed from anatase phase to rutile phase. In the transition process, peak intensities of rutile TiO2 1 0 1, 1 1 1 and 2 1 1 planes of X-ray diffraction characteristically increased. The contact angles of water droplets on the anodize TiO2 were monotonously decreased with the progress of the anodization except on the characteristically oriented rutile surface. In the evaluations of acetaldehyde photocatalysis under UV illumination, the anatase TiO2 anodized for short period exhibited high activities. On the other hand, when illuminated with visible light (>422 nm), rutile-structured TiO2 formed by anodization with a long duration exhibited superior photocatalytic activities probably due to high rutile fraction and sulfur incorporation from the electrolyte.

Sound localization and word discrimination in reverberant environment in children with developmental dyslexia.

PubMed

Castro-Camacho, Wendy; Peñaloza-López, Yolanda; Pérez-Ruiz, Santiago J; García-Pedroza, Felipe; Padilla-Ortiz, Ana L; Poblano, Adrián; Villarruel-Rivas, Concepción; Romero-Díaz, Alfredo; Careaga-Olvera, Aidé

2015-04-01

Compare if localization of sounds and words discrimination in reverberant environment is different between children with dyslexia and controls. We studied 30 children with dyslexia and 30 controls. Sound and word localization and discrimination was studied in five angles from left to right auditory fields (-90o, -45o, 0o, +45o, +90o), under reverberant and no-reverberant conditions; correct answers were compared. Spatial location of words in no-reverberant test was deficient in children with dyslexia at 0º and +90o. Spatial location for reverberant test was altered in children with dyslexia at all angles, except –-90o. Word discrimination in no-reverberant test in children with dyslexia had a poor performance at left angles. In reverberant test, children with dyslexia exhibited deficiencies at -45o, -90o, and +45o angles. Children with dyslexia could had problems when have to locate sound, and discriminate words in extreme locations of the horizontal plane in classrooms with reverberation.

Linearized Lifting-Surface and Lifting-line Evaluations of Sidewash Behind Rolling Triangular Wings at Supersonic Speeds

NASA Technical Reports Server (NTRS)

Bobbitt, Percy J

1957-01-01

The lifting-surface sidewash behind rolling triangular wings has been derived for a range of supersonic Mach numbers for which the wing leading edges remain swept behind the mark cone emanating from the wing apex. Variations of the sidewash with longitudinal distance in the vertical plane of symmetry are presented in graphical form. An approximate expression for the sidewash has been developed by means of an approach using a horseshoe-vortex approximate-lifting-line theory. By use of this approximate expression, sidewash may be computed for wings of arbitrary plan form and span loading. A comparison of the sidewash computed by lifting-surface and lifting-line expressions for the triangular wing showed good agreement except in the vicinity of the trailing edge when the leading edge approached the sonic condition. An illustrative calculation has been made of the force induced by the wing sidewash on a vertical tail located in various longitudinal positions.

Taylor Instability of Incompressible Liquids

DOE R&D Accomplishments Database

Fermi, E.; von Neumann, J.

1955-11-01

A discussion is presented in simplified form of the problem of the growth of an initial ripple on the surface of an incompressible liquid in the presence of an acceleration, g, directed from the outside into the liquid. The model is that of a heavy liquid occupying at t = 0 the half space above the plane z = 0, and a rectangular wave profile is assumed. The theory is found to represent correctly one feature of experimental results, namely the fact that the half wave of the heavy liquid into the vacuum becomes rapidly narrower while the half wave pushing into the heavy liquid becomes more and more blunt. The theory fails to account for the experimental results according to which the front of the wave pushing into the heavy liquid moves with constant velocity. The case of instability at the boundary of 2 fluids of different densities is also explored. Similar results are obtained except that the acceleration of the heavy liquid into the light liquid is reduced.

Analysis of digital images into energy-angular momentum modes.

PubMed

Vicent, Luis Edgar; Wolf, Kurt Bernardo

2011-05-01

The measurement of continuous wave fields by a digital (pixellated) screen of sensors can be used to assess the quality of a beam by finding its formant modes. A generic continuous field F(x, y) sampled at an N × N Cartesian grid of point sensors on a plane yields a matrix of values F(q(x), q(y)), where (q(x), q(y)) are integer coordinates. When the approximate rotational symmetry of the input field is important, one may use the sampled Laguerre-Gauss functions, with radial and angular modes (n, m), to analyze them into their corresponding coefficients F(n, m) of energy and angular momentum (E-AM). The sampled E-AM modes span an N²-dimensional space, but are not orthogonal--except for parity. In this paper, we propose the properly orthonormal "Laguerre-Kravchuk" discrete functions Λ(n, m)(q(x), q(y)) as a convenient basis to analyze the sampled beams into their E-AM polar modes, and with them synthesize the input image exactly.

Observation of longitudinal spin-Seebeck effect in cobalt-ferrite epitaxial thin films

NASA Astrophysics Data System (ADS)

Niizeki, Tomohiko; Kikkawa, Takashi; Uchida, Ken-ichi; Oka, Mineto; Suzuki, Kazuya Z.; Yanagihara, Hideto; Kita, Eiji; Saitoh, Eiji

2015-05-01

The longitudinal spin-Seebeck effect (LSSE) has been investigated in cobalt ferrite (CFO), an exceptionally hard magnetic spinel ferrite. A bilayer of a polycrystalline Pt and an epitaxially-strained CFO(110) exhibiting an in-plane uniaxial anisotropy was prepared by reactive rf sputtering technique. Thermally generated spin voltage in the CFO layer was measured via the inverse spin-Hall effect in the Pt layer. External-magnetic-field (H) dependence of the LSSE voltage (VLSSE) in the Pt/CFO(110) sample with H ∥ [001] was found to exhibit a hysteresis loop with a high squareness ratio and high coercivity, while that with H ∥ [ 1 1 ¯ 0 ] shows a nearly closed loop, reflecting the different anisotropies induced by the epitaxial strain. The magnitude of VLSSE has a linear relationship with the temperature difference (ΔT), giving the relatively large VLSSE /ΔT of about 3 μV/K for CFO(110) which was kept even at zero external field.

A Novel Automated Method for Analyzing Cylindrical Computed Tomography Data

NASA Technical Reports Server (NTRS)

Roth, D. J.; Burke, E. R.; Rauser, R. W.; Martin, R. E.

2011-01-01

A novel software method is presented that is applicable for analyzing cylindrical and partially cylindrical objects inspected using computed tomography. This method involves unwrapping and re-slicing data so that the CT data from the cylindrical object can be viewed as a series of 2-D sheets in the vertical direction in addition to volume rendering and normal plane views provided by traditional CT software. The method is based on interior and exterior surface edge detection and under proper conditions, is FULLY AUTOMATED and requires no input from the user except the correct voxel dimension from the CT scan. The software is available from NASA in 32- and 64-bit versions that can be applied to gigabyte-sized data sets, processing data either in random access memory or primarily on the computer hard drive. Please inquire with the presenting author if further interested. This software differentiates itself in total from other possible re-slicing software solutions due to complete automation and advanced processing and analysis capabilities.

On the nature of the symbiotic binary AX Persei

NASA Technical Reports Server (NTRS)

Mikolajewska, Joanna; Kenyon, Scott J.

1992-01-01

Photometric and spectroscopic observations of the symbiotic binary AX Persei are presented. This system contains a red giant that fills its tidal lobe and transfers material into an accretion disk surrounding a low-mass main-sequence star. The stellar masses - 1 solar mass for the red giant and about 0.4 solar mass for the companion - suggest AX Per is poised to enter a common envelope phase of evolution. The disk luminosity increases from L(disk) about 100 solar luminosity in quiescence to L(disk) about 5700 solar luminosity in outburst for a distance of d = 2.5 kpc. Except for visual maximum, high ionization permitted emission lines - such as He II - imply an EUV luminosity comparable to the disk luminosity. High-energy photons emitted by a hot boundary layer between the disk and central star ionize a surrounding nebula to produce this permitted line emission. High ionization forbidden lines form in an extended, shock-excited region well out of the binary's orbital plane and may be associated with mass loss from the disk.

Infrared Organic Light-Emitting Diodes with Carbon Nanotube Emitters.

PubMed

Graf, Arko; Murawski, Caroline; Zakharko, Yuriy; Zaumseil, Jana; Gather, Malte C

2018-03-01

While organic light-emitting diodes (OLEDs) covering all colors of the visible spectrum are widespread, suitable organic emitter materials in the near-infrared (nIR) beyond 800 nm are still lacking. Here, the first OLED based on single-walled carbon nanotubes (SWCNTs) as the emitter is demonstrated. By using a multilayer stacked architecture with matching charge blocking and charge-transport layers, narrow-band electroluminescence at wavelengths between 1000 and 1200 nm is achieved, with spectral features characteristic of excitonic and trionic emission of the employed (6,5) SWCNTs. Here, the OLED performance is investigated in detail and it is found that local conduction hot-spots lead to pronounced trion emission. Analysis of the emissive dipole orientation shows a strong horizontal alignment of the SWCNTs with an average inclination angle of 12.9° with respect to the plane, leading to an exceptionally high outcoupling efficiency of 49%. The SWCNT-based OLEDs represent a highly attractive platform for emission across the entire nIR. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel polymer-free iridescent lamellar hydrogel for two-dimensional confined growth of ultrathin gold membranes

NASA Astrophysics Data System (ADS)

Niu, Jian; Wang, Dong; Qin, Haili; Xiong, Xiong; Tan, Pengli; Li, Youyong; Liu, Rui; Lu, Xuxing; Wu, Jian; Zhang, Ting; Ni, Weihai; Jin, Jian

2014-02-01

Hydrogels are generally thought to be formed by nano- to micrometre-scale fibres or polymer chains, either physically branched or entangled with each other to trap water. Although there are also anisotropic hydrogels with apparently ordered structures, they are essentially polymer fibre/discrete polymer chains-based network without exception. Here we present a type of polymer-free anisotropic lamellar hydrogels composed of 100-nm-thick water layers sandwiched by two bilayer membranes of a self-assembled nonionic surfactant, hexadecylglyceryl maleate. The hydrogels appear iridescent as a result of Bragg’s reflection of visible light from the periodic lamellar plane. The particular lamellar hydrogel with extremely wide water spacing was used as a soft two-dimensional template to synthesize single-crystalline nanosheets in the confined two-dimensional space. As a consequence, flexible, ultrathin and large area single-crystalline gold membranes with atomically flat surface were produced in the hydrogel. The optical and electrical properties were detected on a single gold membrane.

Identifying position, visibility, dimensions, and angulation of the ear.

PubMed

Mohamed, Kasim; Christian, Jayanth; Jeyapalan, Karthigeyan; Natarajan, Shanmuganathan; Banu, Fathima; Veeravalli, Padmanabhan T

2014-01-01

We selected 254 subjects between the ages of 18 and 30 yr to assess the ear position, angulations of the ear in relation to the nose, visibility from the frontal view, and dimensions of the ear by using various anthropometric points of the face. Subjects were divided into four groups based on facial form. A reference plane indicator, facial topographical measurements, metal ruler, and digital photography were used. While considering the position of the ear, in all facial forms except square tapering, the most samples showed a tendency for the subaurale being in line with subnasale. Regression analysis showed a tendency to gnathion distance is the most dependent variable with length of the ear kept as a constant predictor, while both interalar distance and exocanthion to endocanthion distance correlate highly significantly to the width of the ear. In all subjects, the visibility of the ear when viewed from the front was an average of 1.5 mm. Regardless of facial form, ear angulation was generally less than nose angulation.

Cephalometrically assessing the validity of superior, middle and inferior tragus points on ala-tragus line while establishing the occlusal plane in edentulous patient

PubMed Central

Thombare, Ram

2013-01-01

PURPOSE The purpose of this study was to decide the most appropriate point on tragus to be used as a reference point at time of marking ala tragus line while establishing occlusal plane. MATERIALS AND METHODS The data was collected in two groups of subjects: 1) Dentulous 2) Edentulous group having sample size of 30 for each group with equal gender distribution (15 males, 15 females each). Downs analysis was used for base value. Lateral cephalographs were taken for all selected subjects. Three points were marked on tragus as Superior (S), Middle (M), and Inferior (I) and were joined with ala (A) of the nose to form ala-tragus lines. The angle formed by each line (SA plane, MA plane, IA plane) with Frankfort Horizontal (FH) plane was measured by using custom made device and modified protractor in all dentulous and edentulous subjects. Also, in dentulous subjects angle between Frankfort Horizontal plane and natural occlusal plane was measured. The measurements obtained were subjected to the following statistical tests; descriptive analysis, Student's unpaired t-test and Pearson's correlation coefficient. RESULTS The results demonstrated, the mean angle COO (cant of occlusal plane) as 9.76°, inferior point on tragus had given the mean angular value of IFH [Angle between IA plane (plane formed by joining inferior point-I on tragus and ala of nose- A) and FH plane) as 10.40° and 10.56° in dentulous and edentulous subjects respectively which was the closest value to the angle COO and was comparable with the values of angle COO value in Downs analysis. Angulations of ala-tragus line marked from inferior point with occlusal plane in dentulous subject had given the smallest value 2.46° which showed that this ala-tragus line was nearly parallel to occlusal plane. CONCLUSION The inferior point marked on tragus is the most appropriate point for marking ala-tragus line. PMID:23508068

Anti-plane eigenstrain problem of an inclusion of arbitrary shape in an anisotropic bimaterial with a semi-infinite interface crack

NASA Astrophysics Data System (ADS)

Wang, Xu; Schiavone, Peter

2018-02-01

We consider an Eshelby inclusion of arbitrary shape with uniform anti-plane eigenstrains embedded in one of two bonded dissimilar anisotropic half planes containing a semi-infinite interface crack situated along the negative real axis. Using two consecutive conformal mappings, the upper and lower halves of the physical plane are first mapped onto two separate quarters of the image plane. The corresponding boundary value problem is then analyzed in this image plane rather than in the original physical plane. Corresponding analytic functions in all three phases of the composite are derived via the construction of an auxiliary function and repeated application of analytic continuation across the real and imaginary axes in the image plane. As a result, the local stress intensity factor is then obtained explicitly. Perhaps most interestingly, we find that the satisfaction of a particular condition makes the inclusion (stress) invisible to the crack.

Comparing trapezius muscle activity in the different planes of shoulder elevation

PubMed Central

Ishigaki, Tomonobu; Ishida, Tomoya; Samukawa, Mina; Saito, Hiroshi; Hirokawa, Motoki; Ezawa, Yuya; Sugawara, Makoto; Tohyama, Harukazu; Yamanaka, Masanori

2015-01-01

[Purpose] The purpose of this study was to compare the upper, middle, and lower trapezius muscles’ activity in the different planes of shoulder elevation. [Subjects] Twenty male subjects volunteered for this study. [Methods] Surface electromyographic (EMG) activity for each of the three regions of the trapezius muscles in the three different planes of elevation were collected while the participants maintained 30, 60, and 90 degrees of elevation in each plane. The EMG data were normalized with maximum voluntary isometric contraction (%MVIC), and compared among the planes at each angle of elevation. [Results] There were significantly different muscle activities among the elevation planes at each angle. [Conclusion] This study found that the three regions of the trapezius muscles changed their activity depending on the planes of shoulder elevation. These changes in the trapezius muscles could induce appropriate scapular motion to face the glenoid cavity in the correct directions in different planes of shoulder elevation. PMID:26157248

Comparing trapezius muscle activity in the different planes of shoulder elevation.

PubMed

Ishigaki, Tomonobu; Ishida, Tomoya; Samukawa, Mina; Saito, Hiroshi; Hirokawa, Motoki; Ezawa, Yuya; Sugawara, Makoto; Tohyama, Harukazu; Yamanaka, Masanori

2015-05-01

[Purpose] The purpose of this study was to compare the upper, middle, and lower trapezius muscles' activity in the different planes of shoulder elevation. [Subjects] Twenty male subjects volunteered for this study. [Methods] Surface electromyographic (EMG) activity for each of the three regions of the trapezius muscles in the three different planes of elevation were collected while the participants maintained 30, 60, and 90 degrees of elevation in each plane. The EMG data were normalized with maximum voluntary isometric contraction (%MVIC), and compared among the planes at each angle of elevation. [Results] There were significantly different muscle activities among the elevation planes at each angle. [Conclusion] This study found that the three regions of the trapezius muscles changed their activity depending on the planes of shoulder elevation. These changes in the trapezius muscles could induce appropriate scapular motion to face the glenoid cavity in the correct directions in different planes of shoulder elevation.

From the Dance of the Foci to a Strophoid

ERIC Educational Resources Information Center

Jobbings, Andrew

2011-01-01

The intersection of a plane and a cone is a conic section and rotating the plane leads to a family of conics. What happens to the foci of these conics as the plane rotates? A classical result gives the locus of the foci as an oblique strophoid when the plane rotates about a tangent to the cone. The analogous curve when the plane intersects a…

Assessing potential errors of MRI-based measurements of pulmonary blood flow using a detailed network flow model

PubMed Central

Buxton, R. B.; Prisk, G. K.

2012-01-01

MRI images of pulmonary blood flow using arterial spin labeling (ASL) measure the delivery of magnetically tagged blood to an image plane during one systolic ejection period. However, the method potentially suffers from two problems, each of which may depend on the imaging plane location: 1) the inversion plane is thicker than the imaging plane, resulting in a gap that blood must cross to be detected in the image; and 2) ASL includes signal contributions from tagged blood in conduit vessels (arterial and venous). By using an in silico model of the pulmonary circulation we found the gap reduced the ASL signal to 64–74% of that in the absence of a gap in the sagittal plane and 53–84% in the coronal. The contribution of the conduit vessels varied markedly as a function of image plane ranging from ∼90% of the overall signal in image planes that encompass the central hilar vessels to <20% in peripheral image planes. A threshold cutoff removing voxels with intensities >35% of maximum reduced the conduit vessel contribution to the total ASL signal to ∼20% on average; however, planes with large contributions from conduit vessels underestimate acinar flow due to a high proportion of in-plane flow, making ASL measurements of perfusion impractical. In other image planes, perfusion dominated the resulting ASL images with good agreement between ASL and acinar flow. Similarly, heterogeneity of the ASL signal as measured by relative dispersion is a reliable measure of heterogeneity of the acinar flow distribution in the same image planes. PMID:22539167

Assessing potential errors of MRI-based measurements of pulmonary blood flow using a detailed network flow model.

PubMed

Burrowes, K S; Buxton, R B; Prisk, G K

2012-07-01

MRI images of pulmonary blood flow using arterial spin labeling (ASL) measure the delivery of magnetically tagged blood to an image plane during one systolic ejection period. However, the method potentially suffers from two problems, each of which may depend on the imaging plane location: 1) the inversion plane is thicker than the imaging plane, resulting in a gap that blood must cross to be detected in the image; and 2) ASL includes signal contributions from tagged blood in conduit vessels (arterial and venous). By using an in silico model of the pulmonary circulation we found the gap reduced the ASL signal to 64-74% of that in the absence of a gap in the sagittal plane and 53-84% in the coronal. The contribution of the conduit vessels varied markedly as a function of image plane ranging from ∼90% of the overall signal in image planes that encompass the central hilar vessels to <20% in peripheral image planes. A threshold cutoff removing voxels with intensities >35% of maximum reduced the conduit vessel contribution to the total ASL signal to ∼20% on average; however, planes with large contributions from conduit vessels underestimate acinar flow due to a high proportion of in-plane flow, making ASL measurements of perfusion impractical. In other image planes, perfusion dominated the resulting ASL images with good agreement between ASL and acinar flow. Similarly, heterogeneity of the ASL signal as measured by relative dispersion is a reliable measure of heterogeneity of the acinar flow distribution in the same image planes.

Single nanowire light-emitting diodes using uniaxial and coaxial InGaN/GaN multiple quantum wells synthesized by metalorganic chemical vapor deposition.

PubMed

Ra, Yong-Ho; Navamathavan, Rangaswamy; Yoo, Hee-Il; Lee, Cheul-Ro

2014-03-12

We report the controlled synthesis of InGaN/GaN multiple quantum well (MQW) uniaxial (c-plane) and coaxial (m-plane) nanowire (NW) heterostructures by metalorganic chemical vapor deposition. Two kinds of heterostructure NW light-emitting diodes (LEDs) have been fabricated: (1) 10 pairs of InGaN/GaN MQW layers in the c-plane on the top of n-GaN NWs where Mg-doped p-GaN NW is axially grown (2) p-GaN/10 pairs of InGaN/GaN shell structure were surrounded by n-GaN core. Here, we discuss a comparative analysis based on the m-plane and the c-plane oriented InGaN/GaN MQW NW arrays. High-resolution transmission electron microscopy studies revealed that the barrier and the well structures of MQW were observed to be substantially clear with regular intervals while the interface regions were extremely sharp. The c-plane and m-plane oriented MQW single NW was utilized for the parallel assembly fabrication of the LEDs via a focused ion beam. The polarization induced effects on the c-plane and m-plane oriented MQW NWs were precisely compared via power dependence electroluminescence. The electrical properties of m-plane NWs exhibited superior characteristics than that of c-plane NWs owing to the absence of piezoelectric polarization fields. According to this study, high-quality m-plane coaxial NWs can be utilized for the realization of high-brightness LEDs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Kristan D.; Faraj, Daniel A.

In a parallel computer, a plurality of logical planes formed of compute nodes of a subcommunicator may be identified by: for each compute node of the subcommunicator and for a number of dimensions beginning with a first dimension: establishing, by a plane building node, in a positive direction of the first dimension, all logical planes that include the plane building node and compute nodes of the subcommunicator in a positive direction of a second dimension, where the second dimension is orthogonal to the first dimension; and establishing, by the plane building node, in a negative direction of the first dimension,more » all logical planes that include the plane building node and compute nodes of the subcommunicator in the positive direction of the second dimension.« less

High-quality nonpolar a-plane GaN epitaxial films grown on r-plane sapphire substrates by the combination of pulsed laser deposition and metal–organic chemical vapor deposition

NASA Astrophysics Data System (ADS)

Yang, Weijia; Zhang, Zichen; Wang, Wenliang; Zheng, Yulin; Wang, Haiyan; Li, Guoqiang

2018-05-01

High-quality a-plane GaN epitaxial films have been grown on r-plane sapphire substrates by the combination of pulsed laser deposition (PLD) and metal–organic chemical vapor deposition (MOCVD). PLD is employed to epitaxial growth of a-plane GaN templates on r-plane sapphire substrates, and then MOCVD is used. The nonpolar a-plane GaN epitaxial films with relatively small thickness (2.9 µm) show high quality, with the full-width at half-maximum values of GaN(11\\bar{2}0) along [1\\bar{1}00] direction and GaN(10\\bar{1}1) of 0.11 and 0.30°, and a root-mean-square surface roughness of 1.7 nm. This result is equivalent to the quality of the films grown by MOCVD with a thickness of 10 µm. This work provides a new and effective approach for achieving high-quality nonpolar a-plane GaN epitaxial films on r-plane sapphire substrates.