The Nkx5/HMX homeodomain protein MLS-2 is required for proper tube cell shape in the C. elegans excretory system.

PubMed

Abdus-Saboor, Ishmail; Stone, Craig E; Murray, John I; Sundaram, Meera V

2012-06-15

Cells perform wide varieties of functions that are facilitated, in part, by adopting unique shapes. Many of the genes and pathways that promote cell fate specification have been elucidated. However, relatively few transcription factors have been identified that promote shape acquisition after fate specification. Here we show that the Nkx5/HMX homeodomain protein MLS-2 is required for cellular elongation and shape maintenance of two tubular epithelial cells in the C. elegans excretory system, the duct and pore cells. The Nkx5/HMX family is highly conserved from sea urchins to humans, with known roles in neuronal and glial development. MLS-2 is expressed in the duct and pore, and defects in mls-2 mutants first arise when the duct and pore normally adopt unique shapes. MLS-2 cooperates with the EGF-Ras-ERK pathway to turn on the LIN-48/Ovo transcription factor in the duct cell during morphogenesis. These results reveal a novel interaction between the Nkx5/HMX family and the EGF-Ras pathway and implicate a transcription factor, MLS-2, as a regulator of cell shape. Copyright © 2012 Elsevier Inc. All rights reserved.

Structure-function covariation with nonfeeding ecological variables influences evolution of feeding specialization in Carnivora

PubMed Central

Tseng, Z. Jack; Flynn, John J.

2018-01-01

Skull shape convergence is pervasive among vertebrates. Although this is frequently inferred to indicate similar functional underpinnings, neither the specific structure-function linkages nor the selective environments in which the supposed functional adaptations arose are commonly identified and tested. We demonstrate that nonfeeding factors relating to sexual maturity and precipitation-related arboreality also can generate structure-function relationships in the skulls of carnivorans (dogs, cats, seals, and relatives) through covariation with masticatory performance. We estimated measures of masticatory performance related to ecological variables that covary with cranial shape in the mammalian order Carnivora, integrating geometric morphometrics and finite element analyses. Even after accounting for phylogenetic autocorrelation, cranial shapes are significantly correlated to both feeding and nonfeeding ecological variables, and covariation with both variable types generated significant masticatory performance gradients. This suggests that mechanisms of obligate shape covariation with nonfeeding variables can produce performance changes resembling those arising from feeding adaptations in Carnivora. PMID:29441363

Modeling the Coupled Chemo-Thermo-Mechanical Behavior of Amorphous Polymer Networks.

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

Zimmerman, Jonathan A.; Nguyen, Thao D.; Xiao, Rui

2015-02-01

Amorphous polymers exhibit a rich landscape of time-dependent behavior including viscoelasticity, structural relaxation, and viscoplasticity. These time-dependent mechanisms can be exploited to achieve shape-memory behavior, which allows the material to store a programmed deformed shape indefinitely and to recover entirely the undeformed shape in response to specific environmental stimulus. The shape-memory performance of amorphous polymers depends on the coordination of multiple physical mechanisms, and considerable opportunities exist to tailor the polymer structure and shape-memory programming procedure to achieve the desired performance. The goal of this project was to use a combination of theoretical, numerical and experimental methods to investigate themore » effect of shape memory programming, thermo-mechanical properties, and physical and environmental aging on the shape memory performance. Physical and environmental aging occurs during storage and through exposure to solvents, such as water, and can significantly alter the viscoelastic behavior and shape memory behavior of amorphous polymers. This project – executed primarily by Professor Thao Nguyen and Graduate Student Rui Xiao at Johns Hopkins University in support of a DOE/NNSA Presidential Early Career Award in Science and Engineering (PECASE) – developed a theoretical framework for chemothermo- mechanical behavior of amorphous polymers to model the effects of physical aging and solvent-induced environmental factors on their thermoviscoelastic behavior.« less

Minimizing structural vibrations with Input Shaping (TM)

NASA Technical Reports Server (NTRS)

Singhose, Bill; Singer, Neil

1995-01-01

A new method for commanding machines to move with increased dynamic performance was developed. This method is an enhanced version of input shaping, a patented vibration suppression algorithm. This technique intercepts a command input to a system command that moves the mechanical system with increased performance and reduced residual vibration. This document describes many advanced methods for generating highly optimized shaping sequences which are tuned to particular systems. The shaping sequence is important because it determines the trade off between move/settle time of the system and the insensitivity of the input shaping algorithm to variations or uncertainties in the machine which can be controlled. For example, a system with a 5 Hz resonance that takes 1 second to settle can be improved to settle instantaneously using a 0.2 shaping sequence (thus improving settle time by a factor of 5). This system could vary by plus or minus 15% in its natural frequency and still have no apparent vibration. However, the same system shaped with a 0.3 second shaping sequence could tolerate plus or minus 40% or more variation in natural frequency. This document describes how to generate sequences that maximize performance, sequences that maximize insensitivity, and sequences that trade off between the two. Several software tools are documented and included.

Simulation study of geometric shape factor approach to estimating earth emitted flux densities from wide field-of-view radiation measurements

NASA Technical Reports Server (NTRS)

Weaver, W. L.; Green, R. N.

1980-01-01

A study was performed on the use of geometric shape factors to estimate earth-emitted flux densities from radiation measurements with wide field-of-view flat-plate radiometers on satellites. Sets of simulated irradiance measurements were computed for unrestricted and restricted field-of-view detectors. In these simulations, the earth radiation field was modeled using data from Nimbus 2 and 3. Geometric shape factors were derived and applied to these data to estimate flux densities on global and zonal scales. For measurements at a satellite altitude of 600 km, estimates of zonal flux density were in error 1.0 to 1.2%, and global flux density errors were less than 0.2%. Estimates with unrestricted field-of-view detectors were about the same for Lambertian and non-Lambertian radiation models, but were affected by satellite altitude. The opposite was found for the restricted field-of-view detectors.

A proposal for a novel impact factor as an alternative to the JCR impact factor

PubMed Central

Yang, Zu-Guo; Zhang, Chun-Ting

2013-01-01

One disadvantage of the JCR impact factor, the most commonly used assessment tool for ranking and evaluating scientific journals, is its inability in distinguishing among different shapes of citation distribution curves, leading to unfair evaluation of journals in some cases. This paper aims to put forward an alternative impact factor (IF′) that can properly reflect citation distributions. The two impact factors are linearly and positively correlated, and have roughly the same order of magnitude. Because of the ability of IF′ in distinguishing among different shapes of citation distribution curves, IF′ may properly reflect the academic performance of a scientific journal in a way that is different from the JCR impact factor with some unique features that reward journals with highly cited papers. Therefore, it is suggested that IF′ could be used to complement the JCR impact factor. PMID:24296521

A proposal for a novel impact factor as an alternative to the JCR impact factor.

PubMed

Yang, Zu-Guo; Zhang, Chun-Ting

2013-12-03

One disadvantage of the JCR impact factor, the most commonly used assessment tool for ranking and evaluating scientific journals, is its inability in distinguishing among different shapes of citation distribution curves, leading to unfair evaluation of journals in some cases. This paper aims to put forward an alternative impact factor (IF') that can properly reflect citation distributions. The two impact factors are linearly and positively correlated, and have roughly the same order of magnitude. Because of the ability of IF' in distinguishing among different shapes of citation distribution curves, IF' may properly reflect the academic performance of a scientific journal in a way that is different from the JCR impact factor with some unique features that reward journals with highly cited papers. Therefore, it is suggested that IF' could be used to complement the JCR impact factor.

Influence of Molecular Shape on the Thermal Stability and Molecular Orientation of Vapor-Deposited Organic Semiconductors

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

Walters, Diane M; Antony, Lucas; de Pablo, Juan

High thermal stability and anisotropic molecular orientation enhance the performance of vapor-deposited organic semiconductors, but controlling these properties is a challenge in amorphous materials. To understand the influence of molecular shape on these properties, vapor-deposited glasses of three disk-shaped molecules were prepared. For all three systems, enhanced thermal stability is observed for glasses prepared over a wide range of substrate temperatures and anisotropic molecular orientation is observed at lower substrate temperatures. For two of the disk-shaped molecules, atomistic simulations of thin films were also performed and anisotropic molecular orientation was observed at the equilibrium liquid surface. We find that themore » structure and thermal stability of these vapor-deposited glasses results from high surface mobility and partial equilibration toward the structure of the equilibrium liquid surface during the deposition process. For the three molecules studied, molecular shape is a dominant factor in determining the anisotropy of vapor-deposited glasses.« less

Combined preoperative measurement of three inferior alveolar canal factors using computed tomography predicts the risk of inferior alveolar nerve injury during lower third molar extraction.

PubMed

Tachinami, H; Tomihara, K; Fujiwara, K; Nakamori, K; Noguchi, M

2017-11-01

A retrospective cohort study was performed to assess the clinical usefulness of combination assessment using computed tomography (CT) images in patients undergoing third molar extraction. This study included 85 patients (124 extraction sites). The relationship between cortication status, buccolingual position, and shape of the inferior alveolar canal (IAC) on CT images and the incidence of inferior alveolar nerve (IAN) injury after third molar extraction was evaluated. IAN injury was observed at eight of the 124 sites (6.5%), and in five of 19 sites (26.3%) in which cortication was absent+the IAC had a lingual position+the IAC had a dumbbell shape. Significant relationships were found between IAN injury and the three IAC factors (cortication status, IAC position, and IAC shape; P=0.0001). In patients with the three IAC factors, logistic regression analysis indicated a strong association between these factors and IAN injury (P=0.007). An absence of cortication, a lingually positioned IAC, and a dumbbell-shaped IAC are considered to indicate a high risk of IAN injury according to the logistic regression analysis (P=0.007). These results suggest that a combined assessment of these three IAC factors could be useful for the improved prediction of IAN injury. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Pulse-shape discrimination and energy quenching of alpha particles in Cs2LiLaBr6:Ce3+

NASA Astrophysics Data System (ADS)

Mesick, K. E.; Coupland, D. D. S.; Stonehill, L. C.

2017-01-01

Cs2LiLaBr6:Ce3+(CLLB) is an elpasolite scintillator that offers excellent linearity and gamma-ray energy resolution and sensitivity to thermal neutrons with the ability to perform pulse-shape discrimination (PSD) to distinguish gammas and neutrons. Our investigation of CLLB has indicated the presence of intrinsic radioactive alpha background that we have determined to be from actinium contamination of the lanthanum component. We measured the pulse shapes for gamma, thermal neutron, and alpha events and determined that PSD can be performed to separate the alpha background with a moderate figure of merit of 0.98. We also measured the electron-equivalent-energy of the alpha particles in CLLB and simulated the intrinsic alpha background from 227Ac to determine the quenching factor of the alphas. A linear quenching relationship Lα =Eα × q +L0 was found at alpha particle energies above 5 MeV, with a quenching factor q = 0.71 MeVee / MeV and an offset L0 = - 1.19 MeVee .

Detection of sub-kilometer craters in high resolution planetary images using shape and texture features

NASA Astrophysics Data System (ADS)

Bandeira, Lourenço; Ding, Wei; Stepinski, Tomasz F.

2012-01-01

Counting craters is a paramount tool of planetary analysis because it provides relative dating of planetary surfaces. Dating surfaces with high spatial resolution requires counting a very large number of small, sub-kilometer size craters. Exhaustive manual surveys of such craters over extensive regions are impractical, sparking interest in designing crater detection algorithms (CDAs). As a part of our effort to design a CDA, which is robust and practical for planetary research analysis, we propose a crater detection approach that utilizes both shape and texture features to identify efficiently sub-kilometer craters in high resolution panchromatic images. First, a mathematical morphology-based shape analysis is used to identify regions in an image that may contain craters; only those regions - crater candidates - are the subject of further processing. Second, image texture features in combination with the boosting ensemble supervised learning algorithm are used to accurately classify previously identified candidates into craters and non-craters. The design of the proposed CDA is described and its performance is evaluated using a high resolution image of Mars for which sub-kilometer craters have been manually identified. The overall detection rate of the proposed CDA is 81%, the branching factor is 0.14, and the overall quality factor is 72%. This performance is a significant improvement over the previous CDA based exclusively on the shape features. The combination of performance level and computational efficiency offered by this CDA makes it attractive for practical application.

Impacts of Implosion Asymmetry And Hot Spot Shape On Ignition Capsules

NASA Astrophysics Data System (ADS)

Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming; Yi, S. Austin; Batha, Steve

2017-10-01

Implosion symmetry plays a critical role in achieving high areal density and internal energy at stagnation during hot spot formation in ICF capsules. Asymmetry causes hot spot irregularity and stagnation de-synchronization that results in lower temperatures and areal densities of the hot fuel. These degradations significantly affect the alpha heating process in the DT fuel as well as on the thermonuclear performance of the capsules. In this work, we explore the physical factors determining the shape of the hot spot late in the implosion and the effects of shape on Î+/-particle transport. We extend our ignition theory [1-4] to include the hot spot shape and quantify the effects of the implosion asymmetry on both the ignition criterion and capsule performance. We validate our theory with the NIF existing experimental data Our theory shows that the ignition criterion becomes more restrictive with the deformation of the hot spot. Through comparison with the NIF data, we demonstrate that the shape effects on the capsules' performance become more explicit as the self-heating and yield of the capsules increases. The degradation of the thermonuclear burn by the hot spot shape for high yield shots to date can be as high as 20%. Our theory is in good agreement with the NIF data. This work was performed under the auspices of the U.S. Department of Energy by the Los Alamos National Laboratory under Contract No. W-7405-ENG-36.

Motivation of health surveillance assistants in Malawi: A qualitative study.

PubMed

Chikaphupha, Kingsley R; Kok, Maryse C; Nyirenda, Lot; Namakhoma, Ireen; Theobald, Sally

2016-06-01

Motivation of health workers is a critical component of performance and is shaped by multiple factors. This study explored factors that influence motivation of health surveillance assistants (HSAs) in Malawi, with the aim of identifying interventions that can be applied to enhance motivation and performance of HSAs. A qualitative study capturing the perspectives of purposively selected participants was conducted in two districts: Salima and Mchinji. Participants included HSAs, health managers, and various community members. Data were collected through focus group discussions (n = 16) and in-depth interviews (n = 44). The study sample was comprised of 112 women and 65 men. Qualitative data analysis was informed by existing frameworks on factors influencing health worker motivation. Our analysis identified five key themes shaping HSA motivation: salary, accommodation, human resource management, supplies and logistics, and community links. Each of these played out at different levels-individual, family, community, and organisational-with either positive or negative effects. Demotivating factors related primarily to the organisational level, while motivating factors were more often related to individual, family, and community levels. A lack of financial incentives and shortages of basic supplies and materials were key factors demotivating HSAs. Supervision was generally perceived as unsupportive, uncoordinated, and top-down. Most HSAs complained of heavy workload. Many HSAs felt further recognition and support from the Ministry of Health, and the development of a clear career pathway would improve their motivation. Factors shaping motivation of HSAs are complex and multilayered; experiences at one level will impact other levels. Interventions are required to enhance HSA motivation, including strengthening the supervision system, developing career progression pathways, and ensuring clear and transparent incentives. HSAs have unique experiences, and there is need to hear and address these to better enable HSAs to cope with the challenging conditions they work in.

Wavefront control performance modeling with WFIRST shaped pupil coronagraph testbed

NASA Astrophysics Data System (ADS)

Zhou, Hanying; Nemati, Bijian; Krist, John; Cady, Eric; Kern, Brian; Poberezhskiy, Ilya

2017-09-01

NASA's WFIRST mission includes a coronagraph instrument (CGI) for direct imaging of exoplanets. Significant improvement in CGI model fidelity has been made recently, alongside a testbed high contrast demonstration in a simulated dynamic environment at JPL. We present our modeling method and results of comparisons to testbed's high order wavefront correction performance for the shaped pupil coronagraph. Agreement between model prediction and testbed result at better than a factor of 2 has been consistently achieved in raw contrast (contrast floor, chromaticity, and convergence), and with that comes good agreement in contrast sensitivity to wavefront perturbations and mask lateral shear.

Improved safety of retinal photocoagulation with a shaped beam and modulated pulse

NASA Astrophysics Data System (ADS)

Sramek, Christopher; Brown, Jefferson; Paulus, Yannis M.; Nomoto, Hiroyuki; Palanker, Daniel

2010-02-01

Shorter pulse durations help confine thermal damage during retinal photocoagulation, decrease treatment time and minimize pain. However, safe therapeutic window (the ratio of threshold powers for rupture and mild coagulation) decreases with shorter exposures. A ring-shaped beam enables safer photocoagulation than conventional beams by reducing the maximum temperature in the center of the spot. Similarly, a temporal pulse modulation decreasing its power over time improves safety by maintaining constant temperature for a significant portion of the pulse. Optimization of the beam and pulse shapes was performed using a computational model. In vivo experiments were performed to verify the predicted improvement. With each of these approaches, the pulse duration can be decreased by a factor of two, from 20 ms down to 10 ms while maintaining the same therapeutic window.

Real-time In-Flight Strain and Deflection Monitoring with Fiber Optic Sensors

NASA Technical Reports Server (NTRS)

Richards, Lance; Parker, Allen R.; Ko, William L.; Piazza, Anthony

2008-01-01

This viewgraph presentation reviews Dryden's efforts to develop in-flight monitoring based on Fiber Optics. One of the motivating factors for this development was the breakup of the Helios aircraft. On Ikhana the use of fiber optics for wing shape sensing is being developed. They are being used to flight validate fiber optic sensor measurements and real-time wing shape sensing predictions on NASA's Ikhana vehicle; validate fiber optic mathematical models and design tools; Assess technical viability and, if applicable, develop methodology and approach to incorporate wing shape measurements within the vehicle flight control system, and develop and flight validate advanced approaches to perform active wing shape control.

Optimized fan-shaped chiral metamaterial as an ultrathin narrow-band circular polarizer at visible frequencies

NASA Astrophysics Data System (ADS)

He, Yizhuo; Wang, Xinghai; Ingram, Whitney; Ai, Bin; Zhao, Yiping

2018-04-01

Chiral metamaterials have the great ability to manipulate the circular polarizations of light, which can be utilized to build ultrathin circular polarizers. Here we build a narrow-band circular polarizer at visible frequencies based on plasmonic fan-shaped chiral nanostructures. In order to achieve the best optical performance, we systematically investigate how different fabrication factors affect the chiral optical response of the fan-shaped chiral nanostructures, including incident angle of vapor depositions, nanostructure thickness, and post-deposition annealing. The optimized fan-shaped nanostructures show two narrow bands for different circular polarizations with the maximum extinction ratios 7.5 and 6.9 located at wavelength 687 nm and 774 nm, respectively.

Feasibility and its characteristics of CO2 laser micromachining-based PMMA anti-scattering grid estimated by MCNP code simulation.

PubMed

Bae, Jun Woo; Kim, Hee Reyoung

2018-01-01

Anti-scattering grid has been used to improve the image quality. However, applying a commonly used linear or parallel grid would cause image distortion, and focusing grid also requires a precise fabrication technology, which is expensive. To investigate and analyze whether using CO2 laser micromachining-based PMMA anti-scattering grid can improve the performance of the grid at a lower cost. Thus, improvement of grid performance would result in improvement of image quality. The cross-sectional shape of CO2 laser machined PMMA is similar to alphabet 'V'. The performance was characterized by contrast improvement factor (CIF) and Bucky. Four types of grid were tested, which include thin parallel, thick parallel, 'V'-type and 'inverse V'-type of grid. For a Bucky factor of 2.1, the CIF of the grid with both the "V" and inverse "V" had a value of 1.53, while the thick and thick parallel types had values of 1.43 and 1.65, respectively. The 'V' shape grid manufacture by CO2 laser micromachining showed higher CIF than parallel one, which had same shielding material channel width. It was thought that the 'V' shape grid would be replacement to the conventional parallel grid if it is hard to fabricate the high-aspect-ratio grid.

The Effect of Photon Statistics and Pulse Shaping on the Performance of the Wiener Filter Crystal Identification Algorithm Applied to LabPET Phoswich Detectors

NASA Astrophysics Data System (ADS)

Yousefzadeh, Hoorvash Camilia; Lecomte, Roger; Fontaine, Réjean

2012-06-01

A fast Wiener filter-based crystal identification (WFCI) algorithm was recently developed to discriminate crystals with close scintillation decay times in phoswich detectors. Despite the promising performance of WFCI, the influence of various physical factors and electrical noise sources of the data acquisition chain (DAQ) on the crystal identification process was not fully investigated. This paper examines the effect of different noise sources, such as photon statistics, avalanche photodiode (APD) excess multiplication noise, and front-end electronic noise, as well as the influence of different shaping filters on the performance of the WFCI algorithm. To this end, a PET-like signal simulator based on a model of the LabPET DAQ, a small animal APD-based digital PET scanner, was developed. Simulated signals were generated under various noise conditions with CR-RC shapers of order 1, 3, and 5 having different time constants (τ). Applying the WFCI algorithm to these simulated signals showed that the non-stationary Poisson photon statistics is the main contributor to the identification error of WFCI algorithm. A shaping filter of order 1 with τ = 50 ns yielded the best WFCI performance (error 1%), while a longer shaping time of τ = 100 ns slightly degraded the WFCI performance (error 3%). Filters of higher orders with fast shaping time constants (10-33 ns) also produced good WFCI results (error 1.4% to 1.6%). This study shows the advantage of the pulse simulator in evaluating various DAQ conditions and confirms the influence of the detection chain on the WFCI performance.

Parallel computation of GA search for the artery shape determinants with CFD

NASA Astrophysics Data System (ADS)

Himeno, M.; Noda, S.; Fukasaku, K.; Himeno, R.

2010-06-01

We studied which factors play important role to determine the shape of arteries at the carotid artery bifurcation by performing multi-objective optimization with computation fluid dynamics (CFD) and the genetic algorithm (GA). To perform it, the most difficult problem is how to reduce turn-around time of the GA optimization with 3D unsteady computation of blood flow. We devised two levels of parallel computation method with the following features: level 1: parallel CFD computation with appropriate number of cores; level 2: parallel jobs generated by "master", which finds quickly available job cue and dispatches jobs, to reduce turn-around time. As a result, the turn-around time of one GA trial, which would have taken 462 days with one core, was reduced to less than two days on RIKEN supercomputer system, RICC, with 8192 cores. We performed a multi-objective optimization to minimize the maximum mean WSS and to minimize the sum of circumference for four different shapes and obtained a set of trade-off solutions for each shape. In addition, we found that the carotid bulb has the feature of the minimum local mean WSS and minimum local radius. We confirmed that our method is effective for examining determinants of artery shapes.

Selection of stationary phase particle geometry using X-ray computed tomography and computational fluid dynamics simulations.

PubMed

Schmidt, Irma; Minceva, Mirjana; Arlt, Wolfgang

2012-02-17

The X-ray computed tomography (CT) is used to determine local parameters related to the column packing homogeneity and hydrodynamics in columns packed with spherically and irregularly shaped particles of same size. The results showed that the variation of porosity and axial dispersion coefficient along the column axis is insignificant, compared to their radial distribution. The methodology of using the data attained by CT measurements to perform a CFD simulation of a batch separation of model binary mixtures, with different concentration and separation factors is demonstrated. The results of the CFD simulation study show that columns packed with spherically shaped particles provide higher yield in comparison to columns packed with irregularly shaped particles only below a certain value of the separation factor. The presented methodology can be used for selecting a suited packing material for a particular separation task. Copyright © 2012 Elsevier B.V. All rights reserved.

Shape Optimization of Supersonic Turbines Using Response Surface and Neural Network Methods

NASA Technical Reports Server (NTRS)

Papila, Nilay; Shyy, Wei; Griffin, Lisa W.; Dorney, Daniel J.

2001-01-01

Turbine performance directly affects engine specific impulse, thrust-to-weight ratio, and cost in a rocket propulsion system. A global optimization framework combining the radial basis neural network (RBNN) and the polynomial-based response surface method (RSM) is constructed for shape optimization of a supersonic turbine. Based on the optimized preliminary design, shape optimization is performed for the first vane and blade of a 2-stage supersonic turbine, involving O(10) design variables. The design of experiment approach is adopted to reduce the data size needed by the optimization task. It is demonstrated that a major merit of the global optimization approach is that it enables one to adaptively revise the design space to perform multiple optimization cycles. This benefit is realized when an optimal design approaches the boundary of a pre-defined design space. Furthermore, by inspecting the influence of each design variable, one can also gain insight into the existence of multiple design choices and select the optimum design based on other factors such as stress and materials considerations.

Evaluating the effectiveness of implementing quality management practices in the medical industry.

PubMed

Yeh, T-M; Lai, H-P

2015-01-01

To discuss the effectiveness of 30 quality management practices (QMP) including Strategic Management, Balanced ScoreCard, Knowledge Management, and Total Quality Management in the medical industry. A V-shaped performance evaluation matrix is applied to identify the top ten practices that are important but not easy to use or implement. Quality Function Deployment (QFD) is then utilized to find key factors to improve the implementation of the top ten tools. The questionnaires were sent to the nursing staff and administrators in a hospital through e-mail and posts. A total of 250 copies were distributed and 217 copies were valid. The importance, easiness, and achievement (i.e., implementation level) of 30 quality management practices were used. Key factors for QMP implementation were sequenced in order of importance as top management involvement, inter-department communication and coordination, teamwork, hospital-wide participation, education and training, consultant professionalism, continuous internal auditing, computerized process, and incentive compensation. Top management can implement the V-shaped performance matrix to determine whether quality management practices need improvement and if so, utilize QFD to find the key factors for improvement.

Total systems design analysis of high performance structures

NASA Technical Reports Server (NTRS)

Verderaime, V.

1993-01-01

Designer-control parameters were identified at interdiscipline interfaces to optimize structural systems performance and downstream development and operations with reliability and least life-cycle cost. Interface tasks and iterations are tracked through a matrix of performance disciplines integration versus manufacturing, verification, and operations interactions for a total system design analysis. Performance integration tasks include shapes, sizes, environments, and materials. Integrity integrating tasks are reliability and recurring structural costs. Significant interface designer control parameters were noted as shapes, dimensions, probability range factors, and cost. Structural failure concept is presented, and first-order reliability and deterministic methods, benefits, and limitations are discussed. A deterministic reliability technique combining benefits of both is proposed for static structures which is also timely and economically verifiable. Though launch vehicle environments were primarily considered, the system design process is applicable to any surface system using its own unique filed environments.

Perceptual representation and effectiveness of local figure–ground cues in natural contours

PubMed Central

Sakai, Ko; Matsuoka, Shouhei; Kurematsu, Ken; Hatori, Yasuhiro

2015-01-01

A contour shape strongly influences the perceptual segregation of a figure from the ground. We investigated the contribution of local contour shape to figure–ground segregation. Although previous studies have reported local contour features that evoke figure–ground perception, they were often image features and not necessarily perceptual features. First, we examined whether contour features, specifically, convexity, closure, and symmetry, underlie the perceptual representation of natural contour shapes. We performed similarity tests between local contours, and examined the contribution of the contour features to the perceptual similarities between the contours. The local contours were sampled from natural contours so that their distribution was uniform in the space composed of the three contour features. This sampling ensured the equal appearance frequency of the factors and a wide variety of contour shapes including those comprised of contradictory factors that induce figure in the opposite directions. This sampling from natural contours is advantageous in order to randomly pickup a variety of contours that satisfy a wide range of cue combinations. Multidimensional scaling analyses showed that the combinations of convexity, closure, and symmetry contribute to perceptual similarity, thus they are perceptual quantities. Second, we examined whether the three features contribute to local figure–ground perception. We performed psychophysical experiments to judge the direction of the figure along the local contours, and examined the contribution of the features to the figure–ground judgment. Multiple linear regression analyses showed that closure was a significant factor, but that convexity and symmetry were not. These results indicate that closure is dominant in the local figure–ground perception with natural contours when the other cues coexist with equal probability including contradictory cases. PMID:26579057

Perceptual representation and effectiveness of local figure-ground cues in natural contours.

PubMed

Sakai, Ko; Matsuoka, Shouhei; Kurematsu, Ken; Hatori, Yasuhiro

2015-01-01

A contour shape strongly influences the perceptual segregation of a figure from the ground. We investigated the contribution of local contour shape to figure-ground segregation. Although previous studies have reported local contour features that evoke figure-ground perception, they were often image features and not necessarily perceptual features. First, we examined whether contour features, specifically, convexity, closure, and symmetry, underlie the perceptual representation of natural contour shapes. We performed similarity tests between local contours, and examined the contribution of the contour features to the perceptual similarities between the contours. The local contours were sampled from natural contours so that their distribution was uniform in the space composed of the three contour features. This sampling ensured the equal appearance frequency of the factors and a wide variety of contour shapes including those comprised of contradictory factors that induce figure in the opposite directions. This sampling from natural contours is advantageous in order to randomly pickup a variety of contours that satisfy a wide range of cue combinations. Multidimensional scaling analyses showed that the combinations of convexity, closure, and symmetry contribute to perceptual similarity, thus they are perceptual quantities. Second, we examined whether the three features contribute to local figure-ground perception. We performed psychophysical experiments to judge the direction of the figure along the local contours, and examined the contribution of the features to the figure-ground judgment. Multiple linear regression analyses showed that closure was a significant factor, but that convexity and symmetry were not. These results indicate that closure is dominant in the local figure-ground perception with natural contours when the other cues coexist with equal probability including contradictory cases.

User's manual for CNVUFAC, the general dynamics heat-transfer radiation view factor program

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

Wong, R. L.

CNVUFAC, the General Dynamics heat-transfer radiation veiw factor program, has been adapted for use on the LLL CDC 7600 computer system. The input and output have been modified, and a node incrementing logic was included to make the code compatible with the TRUMP thermal analyzer and related codes. The program performs the multiple integration necessary to evaluate the geometric black-body radiaton node to node view factors. Card image output that contains node number and view factor information is generated for input into the related program GRAY. Program GRAY is then used to include the effects of gray-body emissivities and multiplemore » reflections, generating the effective gray-body view factors usable in TRUMP. CNVUFAC uses an elemental area summation scheme to evaluate the multiple integrals. The program permits shadowing and self-shadowing. The basic configuration shapes that can be considered are cylinders, cones, spheres, ellipsoids, flat plates, disks, toroids, and polynomials of revolution. Portions of these shapes can also be considered.« less

Pulse-shape discrimination and energy quenching of alpha particles in Cs 2LiLaBr 6:Ce 3+

DOE PAGES

Mesick, Katherine Elizabeth; Coupland, Daniel David S.; Stonehill, Laura Catherine

2016-10-19

Cs 2LiLaBr 6:Ce 3+ (CLLB) is an elpasolite scintillator that offers excellent linearity and gamma-ray energy resolution and sensitivity to thermal neutrons with the ability to perform pulse-shape discrimination (PSD) to distinguish gammas and neutrons. Our investigation of CLLB has indicated the presence of intrinsic radioactive alpha background that we have determined to be from actinium contamination of the lanthanum component. We measured the pulse shapes for gamma, thermal neutron, and alpha events and determined that PSD can be performed to separate the alpha background with a moderate figure of merit of 0.98. Here, we also measured the electron-equivalent-energy ofmore » the alpha particles in CLLB and simulated the intrinsic alpha background from 227Ac to determine the quenching factor of the alphas.« less

Application of Taguchi method to optimization of surface roughness during precise turning of NiTi shape memory alloy

NASA Astrophysics Data System (ADS)

Kowalczyk, M.

2017-08-01

This paper describes the research results of surface quality research after the NiTi shape memory alloy (Nitinol) precise turning by the tools with edges made of polycrystalline diamonds (PCD). Nitinol, a nearly equiatomic nickel-titanium shape memory alloy, has wide applications in the arms industry, military, medicine and aerospace industry, and industrial robots. Due to their specific properties NiTi alloys are known to be difficult-to-machine materials particularly by using conventional techniques. The research trials were conducted for three independent parameters (vc, f, ap) affecting the surface roughness were analyzed. The choice of parameter configurations were performed by factorial design methods using orthogonal plan type L9, with three control factors, changing on three levels, developed by G. Taguchi. S/N ratio and ANOVA analyses were performed to identify the best of cutting parameters influencing surface roughness.

Effect of radar frequency on the detection of shaped (low RCS) targets

NASA Astrophysics Data System (ADS)

Moraitis, D.; Alland, S.

The use of shaping to reduce the radar cross-section (RCS) of aircraft and missiles can result in the RCS varying significantly with radar operating frequency. This RCS sensitivity to frequency should be considered when selecting radar frequency and should be accounted for when evaluating radar performance. A detection range increase for shaped (low RCS) targets of a factor of two or greater can be realized for lower frequency radar (e.g., UHF-Band or L-Band) when compared to higher frequency radar (C-Band or X-Band). For low flying (sea skimming) targets, the RCS variation with frequency for shaped (low RCS) targets neutralizes the advantage that higher radar frequencies realize in multipath propagation resulting in approximately the same detection range across the radar bands from UHF to X-Band.

Detector shape in hexagonal sampling grids

NASA Astrophysics Data System (ADS)

Baronti, Stefano; Capanni, Annalisa; Romoli, Andrea; Santurri, Leonardo; Vitulli, Raffaele

2001-12-01

Recent improvements in CCD technology make hexagonal sampling attractive for practical applications and bring a new interest on this topic. In the following the performances of hexagonal sampling are analyzed under general assumptions and compared with the performances of conventional rectangular sampling. This analysis will take into account both the lattice form (squared, rectangular, hexagonal, and regular hexagonal), and the pixel shape. The analyzed hexagonal grid will not based a-priori on a regular hexagon tessellation, i.e., no constraints will be made on the ratio between the sampling frequencies in the two spatial directions. By assuming an elliptic support for the spectrum of the signal being sampled, sampling conditions will be expressed for a generic hexagonal sampling grid, and a comaprison with the well-known sampling conditions for a comparable rectangular lattice will be performed. Further, by considering for sake of clarity a spectrum with a circular support, the comparison will be performed under the assumption of same number of pixels for unity of surface, and the particular case of regular hexagonal sampling grid will also be considered. Regular hexagonal lattice with regular hexagonal sensitivity shape of the detector elements will result as the best trade-off between the proposed sampling requirement. Concerning the detector shape, the hexagonal is more advantageous than the rectangular. To show that a figure of merit is defined which takes into account that the MTF (modulation transfer function) of a hexagonal detector is not separable, conversely from that of a rectangular detector. As a final result, octagonal shape detectors are compared to those with rectangular and hexagonal shape in the two hypotheses of equal and ideal fill factor, respectively.

Genomic regions controlling shape variation in the first upper molar of the house mouse

PubMed Central

Pantalacci, Sophie; Turner, Leslie M; Steingrimsson, Eirikur; Renaud, Sabrina

2017-01-01

Numerous loci of large effect have been shown to underlie phenotypic variation between species. However, loci with subtle effects are presumably more frequently involved in microevolutionary processes but have rarely been discovered. We explore the genetic basis of shape variation in the first upper molar of hybrid mice between Mus musculus musculus and M. m. domesticus. We performed the first genome-wide association study for molar shape and used 3D surface morphometrics to quantify subtle variation between individuals. We show that many loci of small effect underlie phenotypic variation, and identify five genomic regions associated with tooth shape; one region contained the gene microphthalmia-associated transcription factor Mitf that has previously been associated with tooth malformations. Using a panel of five mutant laboratory strains, we show the effect of the Mitf gene on tooth shape. This is the first report of a gene causing subtle but consistent variation in tooth shape resembling variation in nature. PMID:29091026

Design of a shape adaptive airfoil actuated by a Shape Memory Alloy strip for airplane tail

NASA Astrophysics Data System (ADS)

Shirzadeh, R.; Raissi Charmacani, K.; Tabesh, M.

2011-04-01

Of the factors that mainly affect the efficiency of the wing during a special flow regime, the shape of its airfoil cross section is the most significant. Airfoils are generally designed for a specific flight condition and, therefore, are not fully optimized in all flight conditions. It is very desirable to have an airfoil with the ability to change its shape based on the current regime. Shape memory alloy (SMA) actuators activate in response to changes in the temperature and can recover their original configuration after being deformed. This study presents the development of a method to control the shape of an airfoil using SMA actuators. To predict the thermomechanical behaviors of an SMA thin strip, 3D incremental formulation of the SMA constitutive model is implemented in FEA software package ABAQUS. The interactions between the airfoil structure and SMA thin strip actuator are investigated. Also, the aerodynamic performance of a standard airfoil with a plain flap is compared with an adaptive airfoil.

Attention Effects on Neural Population Representations for Shape and Location Are Stronger in the Ventral than Dorsal Stream

PubMed Central

2018-01-01

Abstract We examined how attention causes neural population representations of shape and location to change in ventral stream (AIT) and dorsal stream (LIP). Monkeys performed two identical delayed-match-to-sample (DMTS) tasks, attending either to shape or location. In AIT, shapes were more discriminable when directing attention to shape rather than location, measured by an increase in mean distance between population response vectors. In LIP, attending to location rather than shape did not increase the discriminability of different stimulus locations. Even when factoring out the change in mean vector response distance, multidimensional scaling (MDS) still showed a significant task difference in AIT, but not LIP, indicating that beyond increasing discriminability, attention also causes a nonlinear warping of representation space in AIT. Despite single-cell attentional modulations in both areas, our data show that attentional modulations of population representations are weaker in LIP, likely due to a need to maintain veridical representations for visuomotor control. PMID:29876521

A survey of various enhancement techniques for square rings antennas

NASA Astrophysics Data System (ADS)

Mumin, Abdul Rashid O.; Alias, Rozlan; Abdullah, Jiwa; Abdulhasan, Raed Abdulkareem; Ali, Jawad; Dahlan, Samsul Haimi; Awaleh, Abdisamad A.

2017-09-01

The square ring shape becomes a famous reconfiguration on antenna design. The researchers have been developed the square ring by different configurations. It has high efficiency and simple calculation method. The performance enhancement for an antenna is the main reason to use this setting. Furthermore, the multi-objectives for the antenna also are considered. In this paper, different studies of square ring shape are discussed. This shape is developed in five different techniques, which are the gain enhancement, dual band antenna, reconfigurable antenna, CSRR, and circularly polarization. Moreover, the validation between these configurations also demonstrates for square ring shapes. In particular, the square ring slot improved the gain by 4.3 dB, provide dual band resonance at 1.4 and 2.6 GHz while circular polarization at 1.54 GHz, and multi-mode antenna. However, square ring strip achieved an excellent band rejection on UWB antenna at 5.5 GHz. The square ring slot length is the most influential factor on the antenna performance, which refers to the free space wavelength. Finally, comparisons between these techniques are presented.

A Latin-cross-shaped integrated resonant cantilever with second torsion-mode resonance for ultra-resoluble bio-mass sensing

NASA Astrophysics Data System (ADS)

Xia, Xiaoyuan; Zhang, Zhixiang; Li, Xinxin

2008-03-01

Second torsion-mode resonance is proposed for microcantilever biosensors for ultra-high mass-weighing sensitivity and resolution. By increasing both the resonant frequency and Q-factor, the higher mode torsional resonance is favorable for improving the mass-sensing performance. For the first time, a Latin-cross-shaped second-mode resonant cantilever is constructed and optimally designed for both signal-readout and resonance-exciting elements. The cantilever sensor is fabricated by using silicon micromachining techniques. The transverse piezoresistive sensing element and the specific-shaped resonance-exciting loop are successfully integrated in the cantilever. Alpha-fetoprotein (AFP) antibody-antigen specific binding is implemented for the sensing experiment. The proposed cantilever sensor is designed with significantly superior sensitivity to the previously reported first torsion-mode one. After analysis with an Allan variance algorithm, which can be easily embedded in the sensing system, the Latin-cross-shaped second torsion-mode resonant cantilever is evaluated with ultra-high mass resolution. Therefore, the high-performance integrated micro-sensor is promising for on-the-spot bio-molecule detection.

FRamework Assessing Notorious Contributing Influences for Error (FRANCIE): Perspective on Taxonomy Development to Support Error Reporting and Analysis

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

Lon N. Haney; David I. Gertman

2003-04-01

Beginning in the 1980s a primary focus of human reliability analysis was estimation of human error probabilities. However, detailed qualitative modeling with comprehensive representation of contextual variables often was lacking. This was likely due to the lack of comprehensive error and performance shaping factor taxonomies, and the limited data available on observed error rates and their relationship to specific contextual variables. In the mid 90s Boeing, America West Airlines, NASA Ames Research Center and INEEL partnered in a NASA sponsored Advanced Concepts grant to: assess the state of the art in human error analysis, identify future needs for human errormore » analysis, and develop an approach addressing these needs. Identified needs included the need for a method to identify and prioritize task and contextual characteristics affecting human reliability. Other needs identified included developing comprehensive taxonomies to support detailed qualitative modeling and to structure meaningful data collection efforts across domains. A result was the development of the FRamework Assessing Notorious Contributing Influences for Error (FRANCIE) with a taxonomy for airline maintenance tasks. The assignment of performance shaping factors to generic errors by experts proved to be valuable to qualitative modeling. Performance shaping factors and error types from such detailed approaches can be used to structure error reporting schemes. In a recent NASA Advanced Human Support Technology grant FRANCIE was refined, and two new taxonomies for use on space missions were developed. The development, sharing, and use of error taxonomies, and the refinement of approaches for increased fidelity of qualitative modeling is offered as a means to help direct useful data collection strategies.« less

Human performance modeling for system of systems analytics: combat performance-shaping factors.

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

Lawton, Craig R.; Miller, Dwight Peter

The US military has identified Human Performance Modeling (HPM) as a significant requirement and challenge of future systems modeling and analysis initiatives. To support this goal, Sandia National Laboratories (SNL) has undertaken a program of HPM as an integral augmentation to its system-of-system (SoS) analytics capabilities. The previous effort, reported in SAND2005-6569, evaluated the effects of soldier cognitive fatigue on SoS performance. The current effort began with a very broad survey of any performance-shaping factors (PSFs) that also might affect soldiers performance in combat situations. The work included consideration of three different approaches to cognition modeling and how appropriate theymore » would be for application to SoS analytics. This bulk of this report categorizes 47 PSFs into three groups (internal, external, and task-related) and provides brief descriptions of how each affects combat performance, according to the literature. The PSFs were then assembled into a matrix with 22 representative military tasks and assigned one of four levels of estimated negative impact on task performance, based on the literature. Blank versions of the matrix were then sent to two ex-military subject-matter experts to be filled out based on their personal experiences. Data analysis was performed to identify the consensus most influential PSFs. Results indicate that combat-related injury, cognitive fatigue, inadequate training, physical fatigue, thirst, stress, poor perceptual processing, and presence of chemical agents are among the PSFs with the most negative impact on combat performance.« less

Application of CAD/CAE class systems to aerodynamic analysis of electric race cars

NASA Astrophysics Data System (ADS)

Grabowski, L.; Baier, A.; Buchacz, A.; Majzner, M.; Sobek, M.

2015-11-01

Aerodynamics is one of the most important factors which influence on every aspect of a design of a car and car driving parameters. The biggest influence aerodynamics has on design of a shape of a race car body, especially when the main objective of the race is the longest distance driven in period of time, which can not be achieved without low energy consumption and low drag of a car. Designing shape of the vehicle body that must generate the lowest possible drag force, without compromising the other parameters of the drive. In the article entitled „Application of CAD/CAE class systems to aerodynamic analysis of electric race cars” are being presented problems solved by computer analysis of cars aerodynamics and free form modelling. Analysis have been subjected to existing race car of a Silesian Greenpower Race Team. On a basis of results of analysis of existence of Kammback aerodynamic effect innovative car body were modeled. Afterwards aerodynamic analysis were performed to verify existence of aerodynamic effect for innovative shape and to recognize aerodynamics parameters of the shape. Analysis results in the values of coefficients and aerodynamic drag forces. The resulting drag forces Fx, drag coefficients Cx(Cd) and aerodynamic factors Cx*A allowed to compare all of the shapes to each other. Pressure distribution, air velocities and streams courses were useful in determining aerodynamic features of analyzed shape. For aerodynamic tests was used Ansys Fluent CFD software. In a paper the ways of surface modeling with usage of Realize Shape module and classic surface modeling were presented. For shapes modeling Siemens NX 9.0 software was used. Obtained results were used to estimation of existing shapes and to make appropriate conclusions.

The Selective Value of Bacterial Shape

PubMed Central

Young, Kevin D.

2006-01-01

Why do bacteria have shape? Is morphology valuable or just a trivial secondary characteristic? Why should bacteria have one shape instead of another? Three broad considerations suggest that bacterial shapes are not accidental but are biologically important: cells adopt uniform morphologies from among a wide variety of possibilities, some cells modify their shape as conditions demand, and morphology can be tracked through evolutionary lineages. All of these imply that shape is a selectable feature that aids survival. The aim of this review is to spell out the physical, environmental, and biological forces that favor different bacterial morphologies and which, therefore, contribute to natural selection. Specifically, cell shape is driven by eight general considerations: nutrient access, cell division and segregation, attachment to surfaces, passive dispersal, active motility, polar differentiation, the need to escape predators, and the advantages of cellular differentiation. Bacteria respond to these forces by performing a type of calculus, integrating over a number of environmental and behavioral factors to produce a size and shape that are optimal for the circumstances in which they live. Just as we are beginning to answer how bacteria create their shapes, it seems reasonable and essential that we expand our efforts to understand why they do so. PMID:16959965

Measuring Learning and Performance in Collective Training Exercises

DTIC Science & Technology

2008-03-01

Stylistic consistency Consistent use of colors, shapes, font, emphasis techniques, etc. Multi-session management Automatic book marking and "you are...these factors in both the first and last tasks was essential. Hiller’s (2004) cognitive information-processing model (Figure 3) entails six

Infiltrated photonic crystal cavity as a highly sensitive platform for glucose concentration detection

NASA Astrophysics Data System (ADS)

Arafa, Safia; Bouchemat, Mohamed; Bouchemat, Touraya; Benmerkhi, Ahlem; Hocini, Abdesselam

2017-02-01

A Bio-sensing platform based on an infiltrated photonic crystal ring shaped holes cavity-coupled waveguide system is proposed for glucose concentration detection. Considering silicon-on-insulator (SOI) technology, it has been demonstrated that the ring shaped holes configuration provides an excellent optical confinement within the cavity region, which further enhances the light-matter interactions at the precise location of the analyte medium. Thus, the sensitivity and the quality factor (Q) can be significantly improved. The transmission characteristics of light in the biosensor under different refractive indices that correspond to the change in the analyte glucose concentration are analyzed by performing finite-difference time-domain (FDTD) simulations. Accordingly, an improved sensitivity of 462 nm/RIU and a Q factor as high as 1.11х105 have been achieved, resulting in a detection limit of 3.03х10-6 RIU. Such combination of attributes makes the designed structure a promising element for performing label-free biosensing in medical diagnosis and environmental monitoring.

Reducing the effect on the environment by collecting methane plumes.

NASA Astrophysics Data System (ADS)

Nakamura, R.; Aoyama, C.

2017-12-01

Often times, seeping methane plumes can be observed in the vicinity of surface layer methane hydrate. Greenhouse effect of methane gas is approximately 25 times that of carbon dioxide. This is a big influence on the environment. From the investigation performed in 2006 at Umitaka Kaikyaku of the Sea of Japan, the annual amount of methane gas seeping naturally from seafloor was 7.7×105m3/per m2. Methane plume is one of the important factors in considering carbon cycle. In order to collect seeping methane plumes naturally, a method using dome-shaped film was examined. In March, 2016, experiment was performed in the northeast coast of Sado Island in the Sea of Japan using ROV to collect bubbles with a film, using ROV at methane plume gushing point of 150m depth. Bubbles rising into the tubes from dome-shaped film were observed. In June, 2017, another investigation was performed in Umitaka Kaikyaku in offshore Joetsu at Sea of Japan. ROV was used at 890m depth and the experiment was performed with domes made of various materials and shapes. In this study, the author will describe the investigation result.

Morphological and radiological study of ossified superior transverse scapular ligament as potential risk factor of suprascapular nerve entrapment.

PubMed

Polguj, Michał; Sibiński, Marcin; Grzegorzewski, Andrzej; Waszczykowski, Michał; Majos, Agata; Topol, Mirosław

2014-01-01

The suprascapular notch is covered superiorly by the superior transverse scapular ligament. This region is the most common place of suprascapular nerve entrapment formation. The study was performed on 812 specimens: 86 dry scapulae, 104 formalin-fixed cadaveric shoulders, and 622 computer topography scans of scapulae. In the cases with completely ossified superior transverse scapular ligament, the following measurements were performed: proximal and distal width of the bony bridge, middle transverse and vertical diameter of the suprascapular foramen, and area of the suprascapular foramen. An ossified superior transverse scapular ligament was observed more often in men and in the right scapula. The mean age of the subjects with a completely ossified superior transverse scapular ligament was found to be similar than in those without ossification. The ossified band-shaped type of superior transverse scapular ligament was more common than the fan-shaped type and reduced the space below the ligament to a significantly greater degree. The ossified band-shaped type should be taken into consideration as a potential risk factor in the formation of suprascapular nerve entrapment. It could explain the comparable frequency of neuropathy in various populations throughout the world despite the significant differences between them in occurrence of ossified superior transverse scapular ligament.

Computed Tomography Angiography Evaluation of Risk Factors for Unstable Intracranial Aneurysms.

PubMed

Wang, Guang-Xian; Gong, Ming-Fu; Wen, Li; Liu, Lan-Lan; Yin, Jin-Bo; Duan, Chun-Mei; Zhang, Dong

2018-03-19

To evaluate risk factors for instability in intracranial aneurysms (IAs) using computed tomography angiography (CTA). A total of 614 consecutive patients diagnosed with 661 IAs between August 2011 and February 2016 were reviewed. Patients and IAs were divided into stable and unstable groups. Along with clinical characteristics, IA characteristics were evaluated by CTA. Multiple logistic regression analysis was used to identify the independent risk factors associated with unstable IAs. Receiver operating characteristic (ROC) curve analysis was performed on the final model, and optimal thresholds were obtained. Patient age (odds ratio [OR], 0.946), cerebral atherosclerosis (CA; OR, 0.525), and IAs located at the middle cerebral artery (OR, 0.473) or internal carotid artery (OR, 0.512) were negatively correlated with instability, whereas IAs with irregular shape (OR, 2.157), deep depth (OR, 1.557), or large flow angle (FA; OR, 1.015) were more likely to be unstable. ROC analysis revealed threshold values of age, depth, and FA of 59.5 years, 4.25 mm, and 87.8°, respectively. The stability of IAs is significantly affected by several factors, including patient age and the presence of CA. IA shape and location also have an impact on the stability of IAs. Growth into an irregular shape, with a deep depth, and a large FA are risk factors for a change in IAs from stable to unstable. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of thread shape on screw stress concentration by photoelastic measurements

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

Dragoni, E.

1994-11-01

The screw stress concentration for six nut-bolt connections embodying three different thread profiles and two nut shapes is measured photoelastically. Buttress (nearly zero flank angle), trapezoidal (15-deg flank angle), and triangular (30-deg flank angle) thread forms are examined in combination with standard and lip-type nuts. The effect of the thread profile on the screw stress concentration appears to be dependent upon the kind of nut considered. If the fastening incorporates a standard nut, the buttress thread is stronger than the triangular one, which, in turn, behaves better than the trapezoidal contour. The improvement is roughly a 20% reduction in themore » stress concentration factor from the trapezoidal to the buttress thread. In the case of lip nut, conversely, this tendency is somewhat reversed, with the trapezoidal thread performing slightly (but not decidedly) better than the other two shapes. Finally, averaged over all three thread forms, the lip nut exhibits a stress concentration factor which is about 50% lower than that of the standard nut.« less

Business Performance in the Context of Corporate Culture

NASA Astrophysics Data System (ADS)

Haršányová, Petra; Vaňová, Jaromíra; Čambál, Miloš

2016-06-01

Corporate culture is defined as a set of ideas, attitudes, values and behaviour patterns, which are generally accepted and preferred in a company. Company performance is the company's ability to achieve the best results through an evaluation of its assumptions. The article is focused on identifying factors in corporate culture, which changes can increase working satisfaction of employees through targeted shaping of corporate culture, which is ultimately reflected in the performance of the company as a whole.

Comparison of endostapler performance in challenging tissue applications.

PubMed

Contini, Elizabeth; Whiffen, Jennifer; Bronson, Dwight

2013-01-01

Surgical staplers are frequently used in a variety of applications, demanding exacting instrument performance over a huge range of tissue compositions and disease states. The shape of a staple that is formed by a stapling device is one industry-accepted indicator of device performance; typically a B-shaped staple is considered the gold standard for staple formation. This B shape allows blood flow through the tissue, which is one important factor in the healing events that take place clinically after stapling. With the use of an animal model, this ex vivo study investigated staple formation when thick tissue endoscopic staplers were used on challenging and variable tissue. The setting was a corporate institution in the United States. Two 60-mm linear endoscopic thick tissue reloads, a varied-height stapler (VHS), and a single-height stapler (SHS) were fired on 7 different regions of porcine stomach. Resultant staple formation was assessed per region of the stomach and evaluated for proper B-shaped staple formation and staple malformation. The VHS reload had significantly better B-shaped formation (P<.001) for all regions of the stomach and reduced occurrence of malformed staples in 5 of the 7 regions compared with the SHS reload, wherein the remaining 2 regions exhibited comparable malform occurrence. This study compared 2 thick tissue reloads and found that the VHS reload had superior outcomes, with respect to staple formation, compared with the SHS reload. Copyright © 2012 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

Photovoltaic performance of the dome-shaped Fresnel-Köhler concentrator

NASA Astrophysics Data System (ADS)

Zamora, Pablo; Benítez, Pablo; Yang, Li; Miñano, Juan Carlos; Mendes-Lopes, Joao; Araki, Kenji

2012-10-01

In order to have a cost-effective CPV system, two key issues must be ensured: high concentration factor and high tolerance. The novel concentrator we are presenting, the dome-shaped Fresnel-Köhler, can widely fulfill these two and other essential issues in a CPV module. This concentrator is based on two previous successful CPV designs: the FK concentrator with a flat Fresnel lens and the dome-shaped Fresnel lens system developed by Daido Steel, resulting on a superior concentrator. The concentrator has shown outstanding simulation results, achieving an effective concentration-acceptance product (CAP) value of 0.72, and an optical efficiency of 85% on-axis (no anti-reflective coating has been used). Moreover, Köhler integration provides good irradiance uniformity on the cell surface and low spectral aberration of this irradiance. This ensures an optimal performance of the solar cell, maximizing its efficiency. Besides, the domeshaped FK shows optimal results for very compact designs, especially in the f/0.7-1.0 range. The dome-shaped Fresnel- Köhler concentrator, natural and enhanced evolution of the flat FK concentrator, is a cost-effective CPV optical design, mainly due to its high tolerances. Daido Steel advanced technique for demolding injected plastic pieces will allow for easy manufacture of the dome-shaped POE of DFK concentrator.

Telepresence master glove controller for dexterous robotic end-effectors

NASA Technical Reports Server (NTRS)

Fisher, Scott S.

1987-01-01

This paper describes recent research in the Aerospace Human Factors Research Division at NASA's Ames Research Center to develop a glove-like, control and data-recording device (DataGlove) that records and transmits to a host computer in real time, and at appropriate resolution, a numeric data-record of a user's hand/finger shape and dynamics. System configuration and performance specifications are detailed, and current research is discussed investigating its applications in operator control of dexterous robotic end-effectors and for use as a human factors research tool in evaluation of operator hand function requirements and performance in other specialized task environments.

Philosophy of ATHEANA

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

Bley, D.C.; Cooper, S.E.; Forester, J.A.

ATHEANA, a second-generation Human Reliability Analysis (HRA) method integrates advances in psychology with engineering, human factors, and Probabilistic Risk Analysis (PRA) disciplines to provide an HRA quantification process and PRA modeling interface that can accommodate and represent human performance in real nuclear power plant events. The method uses the characteristics of serious accidents identified through retrospective analysis of serious operational events to set priorities in a search process for significant human failure events, unsafe acts, and error-forcing context (unfavorable plant conditions combined with negative performance-shaping factors). ATHEANA has been tested in a demonstration project at an operating pressurized water reactor.

France: Factors Shaping Foreign Policy, and Issues in U.S.-French Relations

DTIC Science & Technology

2009-05-20

TYPE 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE France : Factors Shaping Foreign Policy, and Issues in U.S.- French ...Z39-18 France : Factors Shaping Foreign Policy, and Issues in U.S.- French Relations Congressional Research Service Summary The factors that shape... French foreign policy have changed since the end of the Cold War. The perspectives of France and the United States have diverged in some cases. More

The Effect of Tool Handle Shape on Hand Muscle Load and Pinch Force in a Simulated Dental Scaling Task

PubMed Central

Dong, Hui; Loomer, Peter; Barr, Alan; LaRoche, Charles; Young, Ed; Rempel, David

2007-01-01

Work-related upper extremity musculoskeletal disorders, including carpal tunnel syndrome, are prevalent among dentists and dental hygienists. An important risk factor for developing these disorders is forceful pinching which occurs during periodontal work such as dental scaling. Ergonomically designed dental scaling instruments may help reduce the prevalence of carpal tunnel syndrome among dental practitioners. In this study, 8 custom-designed dental scaling instruments with different handle shapes were used by 24 dentists and dental hygienists to perform a simulated tooth scaling task. The muscle activity of two extensors and two flexors in the forearm was recorded with electromyography while thumb pinch force was measured by pressure sensors. The results demonstrated that the instrument handle with a tapered, round shape and a 10 mm diameter required the least muscle load and pinch force when performing simulated periodontal work. The results from this study can guide dentists and dental hygienists in selection of dental scaling instruments. PMID:17156742

Numerical performance analysis of quartz tuning fork-based force sensors

NASA Astrophysics Data System (ADS)

Dagdeviren, Omur E.; Schwarz, Udo D.

2017-01-01

Quartz tuning fork-based force sensors where one prong is immobilized onto a holder while the other one is allowed to oscillate freely (‘qPlus’ configuration) are in widespread use for high-resolution scanning probe microscopy applications. Due to the small size of the tuning forks (≈3 mm) and the complexity of the sensor assemblies, the reliable and repeatable manufacturing of the sensors has been challenging. In this paper, we investigate the contribution of the amount and location of the epoxy glue used to attach the tuning fork to its holder on the sensor’s performance. Towards this end, we use finite element analysis to model the entire sensor assembly and to perform static and dynamic numerical simulations. Our analysis reveals that increasing the thickness of the epoxy layer between prong and holder results in a decrease of the sensor’s spring constant, eigenfrequency, and quality factor while showing an increasing deviation from oscillation in its primary modal shape. Adding epoxy at the sides of the tuning fork also leads to a degradation of the quality factor even though in this case, spring constant and eigenfrequency rise in tandem with a lessening of the deviation from its ideal modal shape.

Spooled packaging of shape memory alloy actuators

NASA Astrophysics Data System (ADS)

Redmond, John A.

A vast cross-section of transportation, manufacturing, consumer product, and medical technologies rely heavily on actuation. Accordingly, progress in these industries is often strongly coupled to the advancement of actuation technologies. As the field of actuation continues to evolve, smart materials show significant promise for satisfying the growing needs of industry. In particular, shape memory alloy (SMA) wire actuators present an opportunity for low-cost, high performance actuation, but until now, they have been limited or restricted from use in many otherwise suitable applications by the difficulty in packaging the SMA wires within tight or unusually shaped form constraints. To address this packaging problem, SMA wires can be spool-packaged by wrapping around mandrels to make the actuator more compact or by redirecting around multiple mandrels to customize SMA wire pathways to unusual form factors. The goal of this dissertation is to develop the scientific knowledge base for spooled packaging of low-cost SMA wire actuators that enables high, predictable performance within compact, customizable form factors. In developing the scientific knowledge base, this dissertation defines a systematic general representation of single and multiple mandrel spool-packaged SMA actuators and provides tools for their analysis, understanding, and synthesis. A quasi-static analytical model distills the underlying mechanics down to the three effects of friction, bending, and binding, which enables prediction of the behavior of generic spool-packaged SMA actuators with specifiable geometric, loading, frictional, and SMA material parameters. An extensive experimental and simulation-based parameter study establishes the necessary understanding of how primary design tradeoffs between performance, packaging, and cost are governed by the underlying mechanics of spooled actuators. A design methodology outlines a systematic approach to synthesizing high performance SMA wire actuators with mitigated material, power, and packaging costs and compact, customizable form factors. By examining the multi-faceted connections between performance, packaging, and cost, this dissertation builds a knowledge base that goes beyond implementing SMA actuators for particular applications. Rather, it provides a well-developed strategy for realizing the advantages of SMA actuation for a broadened range of applications, thereby enabling opportunities for new functionality and capabilities in industry.

Design and Analysis of Morphing Wing for Unmanned Aerial Vehicles

NASA Astrophysics Data System (ADS)

Galantai, Vlad Paul

This study is concerned with the design and development of a novel wing for UAVs that morphs seamlessly without the use of complex hydraulics, servo motors and controllers. The selected novel design is characterized by a high degree of flight adaptability and improved performance with a limited added weight. These characteristics were attained through the use of shape memory actuators in an antagonistic fashion. Unlike compliant actuators, the antagonistic setup requires the thermal energy to deform the wing but not to maintain its deformed shape. Structural analysis based upon safety factors specified by FAR23 standards and aerodynamic analysis using FLUENT were conducted on the novel design to validate its suitability as a viable wing for UAVs. In addition, thermal conditioning of the shape memory actuators was conducted using a specially designed programmable controller. This thesis does not concern itself with the design of a skin that accommodates the shape changes.

Standing on the shoulders of apes: Analyzing the form and function of the hominoid scapula using geometric morphometrics and finite element analysis.

PubMed

Püschel, Thomas A; Sellers, William I

2016-02-01

The aim was to analyze the relationship between scapular form and function in hominoids by using geometric morphometrics (GM) and finite element analysis (FEA). FEA was used to analyze the biomechanical performance of different hominoid scapulae by simulating static postural scenarios. GM was used to quantify scapular shape differences and the relationship between form and function was analyzed by applying both multivariate-multiple regressions and phylogenetic generalized least-squares regressions (PGLS). Although it has been suggested that primate scapular morphology is mainly a product of function rather than phylogeny, our results showed that shape has a significant phylogenetic signal. There was a significant relationship between scapular shape and its biomechanical performance; hence at least part of the scapular shape variation is due to non-phylogenetic factors, probably related to functional demands. This study has shown that a combined approach using GM and FEA was able to cast some light regarding the functional and phylogenetic contributions in hominoid scapular morphology, thus contributing to a better insight of the association between scapular form and function. © 2015 Wiley Periodicals, Inc.

Measurements of Reduced Hydrodynamic Instability Growth in Adiabat Shaped Implosions at the NIF

NASA Astrophysics Data System (ADS)

Casey, Daniel; Macphee, Andrew; Milovich, Jose; Smalyuk, Vladimir; Clark, Dan; Robey, Harry; Peterson, Luc; Baker, Kevin; Weber, Chris

2015-11-01

Hydrodynamic instabilities can cause capsule defects and other perturbations to grow and degrade implosion performance in ignition experiments at the National Ignition Facility (NIF). Radiographic measurements of ablation front perturbation growth were performed using adiabat-shaped drives which are shown to have lower ablation front growth than the low foot drive. This is partly due to faster Richtmyer-Meshkov (RM) oscillations during the shock transit phase of the implosion moving the node in the growth factor spectrum to lower mode numbers reducing the peak growth amplitude. This is demonstrated experimentally by a reversal of the perturbation phase at higher mode numbers (120-160). These results show that the ablation front growth and fuel adiabat can be controlled somewhat-independently and are providing insight into new, more stable, ignition designs. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

New Approaches For Asteroid Spin State and Shape Modeling From Delay-Doppler Radar Images

NASA Astrophysics Data System (ADS)

Raissi, Chedy; Lamee, Mehdi; Mosiane, Olorato; Vassallo, Corinne; Busch, Michael W.; Greenberg, Adam; Benner, Lance A. M.; Naidu, Shantanu P.; Duong, Nicholas

2016-10-01

Delay-Doppler radar imaging is a powerful technique to characterize the trajectories, shapes, and spin states of near-Earth asteroids; and has yielded detailed models of dozens of objects. Reconstructing objects' shapes and spins from delay-Doppler data is a computationally intensive inversion problem. Since the 1990s, delay-Doppler data has been analyzed using the SHAPE software. SHAPE performs sequential single-parameter fitting, and requires considerable computer runtime and human intervention (Hudson 1993, Magri et al. 2007). Recently, multiple-parameter fitting algorithms have been shown to more efficiently invert delay-Doppler datasets (Greenberg & Margot 2015) - decreasing runtime while improving accuracy. However, extensive human oversight of the shape modeling process is still required. We have explored two new techniques to better automate delay-Doppler shape modeling: Bayesian optimization and a machine-learning neural network.One of the most time-intensive steps of the shape modeling process is to perform a grid search to constrain the target's spin state. We have implemented a Bayesian optimization routine that uses SHAPE to autonomously search the space of spin-state parameters. To test the efficacy of this technique, we compared it to results with human-guided SHAPE for asteroids 1992 UY4, 2000 RS11, and 2008 EV5. Bayesian optimization yielded similar spin state constraints within a factor of 3 less computer runtime.The shape modeling process could be further accelerated using a deep neural network to replace iterative fitting. We have implemented a neural network with a variational autoencoder (VAE), using a subset of known asteroid shapes and a large set of synthetic radar images as inputs to train the network. Conditioning the VAE in this manner allows the user to give the network a set of radar images and get a 3D shape model as an output. Additional development will be required to train a network to reliably render shapes from delay-Doppler images.This work was supported by NASA Ames, NVIDIA, Autodesk and the SETI Institute as part of the NASA Frontier Development Lab program.

Application of Shape Similarity in Pose Selection and Virtual Screening in CSARdock2014 Exercise.

PubMed

Kumar, Ashutosh; Zhang, Kam Y J

2016-06-27

To evaluate the applicability of shape similarity in docking-based pose selection and virtual screening, we participated in the CSARdock2014 benchmark exercise for identifying the correct docking pose of inhibitors targeting factor XA, spleen tyrosine kinase, and tRNA methyltransferase. This exercise provides a valuable opportunity for researchers to test their docking programs, methods, and protocols in a blind testing environment. In the CSARdock2014 benchmark exercise, we have implemented an approach that uses ligand 3D shape similarity to facilitate docking-based pose selection and virtual screening. We showed here that ligand 3D shape similarity between bound poses could be used to identify the native-like pose from an ensemble of docking-generated poses. Our method correctly identified the native pose as the top-ranking pose for 73% of test cases in a blind testing environment. Moreover, the pose selection results also revealed an excellent correlation between ligand 3D shape similarity scores and RMSD to X-ray crystal structure ligand. In the virtual screening exercise, the average RMSD for our pose prediction was found to be 1.02 Å, and it was one of the top performances achieved in CSARdock2014 benchmark exercise. Furthermore, the inclusion of shape similarity improved virtual screening performance of docking-based scoring and ranking. The coefficient of determination (r(2)) between experimental activities and docking scores for 276 spleen tyrosine kinase inhibitors was found to be 0.365 but reached 0.614 when the ligand 3D shape similarity was included.

Restoring warped document images through 3D shape modeling.

PubMed

Tan, Chew Lim; Zhang, Li; Zhang, Zheng; Xia, Tao

2006-02-01

Scanning a document page from a thick bound volume often results in two kinds of distortions in the scanned image, i.e., shade along the "spine" of the book and warping in the shade area. In this paper, we propose an efficient restoration method based on the discovery of the 3D shape of a book surface from the shading information in a scanned document image. From a technical point of view, this shape from shading (SFS) problem in real-world environments is characterized by 1) a proximal and moving light source, 2) Lambertian reflection, 3) nonuniform albedo distribution, and 4) document skew. Taking all these factors into account, we first build practical models (consisting of a 3D geometric model and a 3D optical model) for the practical scanning conditions to reconstruct the 3D shape of the book surface. We next restore the scanned document image using this shape based on deshading and dewarping models. Finally, we evaluate the restoration results by comparing our estimated surface shape with the real shape as well as the OCR performance on original and restored document images. The results show that the geometric and photometric distortions are mostly removed and the OCR results are improved markedly.

Eye Shape Using Partial Coherence Interferometry, Autorefraction and SD OCT

PubMed Central

Clark, Christopher A.; Elsner, Ann E.; Konynenbelt, Benjamin J.

2015-01-01

Purpose Peripheral refraction and retinal shape may influence refractive development. Peripheral refraction has been shown to have a high degree of variability and can take considerable time to perform. SD OCT and peripheral axial length measures may be more reliable, assuming that the retinal position is more important than the peripheral optics of the lens/cornea. Methods 79 subjects right eyes were imaged for this study (age range: 22 to 34 yr, refractive error: −10 to +5.00.) Thirty deg SD OCT (Spectralis, Heidleberg) images were collected in a radial pattern along with peripheral refraction with an autorefractor (Shin-Nippon Auto-refractor) and peripheral axial length measurements with partial coherence interferometry (PCI) (IOLmaster, Zeiss). Statistics were performed using repeat measures ANOVA in SPSS (IBM), Bland-Altman analyses, and regression. All measures were converted to diopters to allow direct comparison. Results SD OCT showed a retinal shape with an increased curvature for myopes compared to emmetropes/hyperopes. This retinal shape change became significant around 5 deg. The SD OCT analysis for retinal shape provides a resolution of 0.026 dipopters, which is about ten times more accurate than using autorefraction or clinical refractive techniques. Bland-Altman analyses suggest that retinal shape measured by SD OCT and the PCI method were more consistent with one another than either was with AR. Conclusions With more accurate measures of retinal shape using SD OCT, consistent differences between emmetrope/hyperopes and myopes were found nearer to the fovea than previously reported. Retinal shape may be influenced by central refractive error, and not merely peripheral optics. Partial coherence interferometry and SD OCT appear to be more accurate than autorefraction, which may be influenced other factors such as fixation and accommodation. Autorefraction does measure the optics directly, which may be a strength of that method. PMID:25437906

Head shape evolution in Tropidurinae lizards: does locomotion constrain diet?

PubMed

Kohlsdorf, T; Grizante, M B; Navas, C A; Herrel, A

2008-05-01

Different components of complex integrated systems may be specialized for different functions, and thus the selective pressures acting on the system as a whole may be conflicting and can ultimately constrain organismal performance and evolution. The vertebrate cranial system is one of the most striking examples of a complex system with several possible functions, being associated to activities as different as locomotion, prey capture, display and defensive behaviours. Therefore, selective pressures on the cranial system as a whole are possibly complex and may be conflicting. The present study focuses on the influence of potentially conflicting selective pressures (diet vs. locomotion) on the evolution of head shape in Tropidurinae lizards. For example, the expected adaptations leading to flat heads and bodies in species living on vertical structures may conflict with the need for improved bite performance associated with the inclusion of hard or tough prey into the diet, a common phenomenon in Tropidurinae lizards. Body size and six variables describing head shape were quantified in preserved specimens of 23 species, and information on diet and substrate usage was obtained from the literature. No phylogenetic signal was observed in the morphological data at any branch length tested, suggesting adaptive evolution of head shape in Tropidurinae. This pattern was confirmed by both factor analysis and independent contrast analysis, which suggested adaptive co-variation between the head shape and the inclusion of hard prey into the diet. In contrast to our expectations, habitat use did not constrain or drive head shape evolution in the group.

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

Mesick, Katherine Elizabeth; Coupland, Daniel David S.; Stonehill, Laura Catherine

Cs 2LiLaBr 6:Ce 3+ (CLLB) is an elpasolite scintillator that offers excellent linearity and gamma-ray energy resolution and sensitivity to thermal neutrons with the ability to perform pulse-shape discrimination (PSD) to distinguish gammas and neutrons. Our investigation of CLLB has indicated the presence of intrinsic radioactive alpha background that we have determined to be from actinium contamination of the lanthanum component. We measured the pulse shapes for gamma, thermal neutron, and alpha events and determined that PSD can be performed to separate the alpha background with a moderate figure of merit of 0.98. Here, we also measured the electron-equivalent-energy ofmore » the alpha particles in CLLB and simulated the intrinsic alpha background from 227Ac to determine the quenching factor of the alphas.« less

Effect of Geometrical Imperfection on Buckling Failure of ITER VVPSS Tank

NASA Astrophysics Data System (ADS)

Jha, Saroj Kumar; Gupta, Girish Kumar; Pandey, Manish Kumar; Bhattacharya, Avik; Jogi, Gaurav; Bhardwaj, Anil Kumar

2017-04-01

The ‘Vacuum Vessel Pressure Suppression System’ (VVPSS) is part of ITER machine, which is designed to protect the ITER Vacuum Vessel and its connected systems, from an over-pressure situation. It is comprised of a partially evacuated tank of stainless steel approximately 46 m long and 6 m in diameter and thickness 30 mm. It is to hold approximately 675 tonnes of water at room temperature to condense the steam resulting from the adverse water leakage into the Vacuum Vessel chamber. For any vacuum vessel, geometrical imperfection has significant effect on buckling failure and structural integrity. Major geometrical imperfection in VVPSS tank depends on form tolerances. To study the effect of geometrical imperfection on buckling failure of VVPSS tank, finite element analysis (FEA) has been performed in line with ASME section VIII division 2 part 5 [1], ‘design by analysis method’. Linear buckling analysis has been performed to get the buckled shape and displacement. Geometrical imperfection due to form tolerance is incorporated in FEA model of VVPSS tank by scaling the resulted buckled shape by a factor ‘60’. This buckled shape model is used as input geometry for plastic collapse and buckling failure assessment. Plastic collapse and buckling failure of VVPSS tank has been assessed by using the elastic-plastic analysis method. This analysis has been performed for different values of form tolerance. The results of analysis show that displacement and load proportionality factor (LPF) vary inversely with form tolerance. For higher values of form tolerance LPF reduces significantly with high values of displacement.

Comparison of multipoint linkage analyses for quantitative traits in the CEPH data: parametric LOD scores, variance components LOD scores, and Bayes factors.

PubMed

Sung, Yun Ju; Di, Yanming; Fu, Audrey Q; Rothstein, Joseph H; Sieh, Weiva; Tong, Liping; Thompson, Elizabeth A; Wijsman, Ellen M

2007-01-01

We performed multipoint linkage analyses with multiple programs and models for several gene expression traits in the Centre d'Etude du Polymorphisme Humain families. All analyses provided consistent results for both peak location and shape. Variance-components (VC) analysis gave wider peaks and Bayes factors gave fewer peaks. Among programs from the MORGAN package, lm_multiple performed better than lm_markers, resulting in less Markov-chain Monte Carlo (MCMC) variability between runs, and the program lm_twoqtl provided higher LOD scores by also including either a polygenic component or an additional quantitative trait locus.

Comparison of multipoint linkage analyses for quantitative traits in the CEPH data: parametric LOD scores, variance components LOD scores, and Bayes factors

PubMed Central

Sung, Yun Ju; Di, Yanming; Fu, Audrey Q; Rothstein, Joseph H; Sieh, Weiva; Tong, Liping; Thompson, Elizabeth A; Wijsman, Ellen M

2007-01-01

We performed multipoint linkage analyses with multiple programs and models for several gene expression traits in the Centre d'Etude du Polymorphisme Humain families. All analyses provided consistent results for both peak location and shape. Variance-components (VC) analysis gave wider peaks and Bayes factors gave fewer peaks. Among programs from the MORGAN package, lm_multiple performed better than lm_markers, resulting in less Markov-chain Monte Carlo (MCMC) variability between runs, and the program lm_twoqtl provided higher LOD scores by also including either a polygenic component or an additional quantitative trait locus. PMID:18466597

Review of Graduate Research on Language Assessment in Turkey between 2011 and 2016

ERIC Educational Resources Information Center

Uzun, Aysenur; Kilickaya, Ferit

2017-01-01

Language assessment is one of the key factors affecting language learning contexts since it not only provides information about the learners and teachers' performance in the classroom but also shapes how languages are learned and practiced depending on how assessment is conducted. Technology, different learner profiles, problems with the existing…

Effects of Missing Data Methods in SEM under Conditions of Incomplete and Nonnormal Data

ERIC Educational Resources Information Center

Li, Jian; Lomax, Richard G.

2017-01-01

Using Monte Carlo simulations, this research examined the performance of four missing data methods in SEM under different multivariate distributional conditions. The effects of four independent variables (sample size, missing proportion, distribution shape, and factor loading magnitude) were investigated on six outcome variables: convergence rate,…

Attitudes and Preferences of Children Living in Orphanage towards Physical Education Lessons

ERIC Educational Resources Information Center

Bendíková, Elena; Nemcek, Dagmar

2017-01-01

Background: The key factor that affects the success of shaping positive attitudes towards the regular life-long performance of a physical activity is the students' level of inner motivation. This is influenced, among other things, by their family background, the educational institution that they attend and the educator's competencies. Objective:…

Design and Development of Peptides from the Anti-Angiogenic Pigment Epithelial-Derived Factor for the Therapy of Prostate Cancer

DTIC Science & Technology

2006-12-01

to perform, but also re- quire substantial amounts of test compound and most rely on selective morphometric analysis (eg, vessel counts, vascular...Several geometric configurations (discoid, spheroid, and so forth) were tested before selecting a cylindrical shape generated by a section of silicone

Determinants of School Performance among Quechua Children in the Peruvian Andes.

ERIC Educational Resources Information Center

Jacoby, Enrique; Pollitt, Ernesto; Cueto, Santiago

1999-01-01

Tests the proposition that family and personal factors, in combination with school characteristics, contribute to the academic progress of Quechua school children. Finds that family background and nutritional history are not as important in shaping educational progress as initially envisioned, but that duration of schooling is an important factor…

Transforming High Schools: Performance Systems for Powerful Teaching. Policy Brief

ERIC Educational Resources Information Center

Haynes, Mariana

2011-01-01

This policy brief examines standards-based approaches that hold promise for shaping a common vision of skilled teaching commensurate with the national goal of preparing all students for college and careers. Numerous studies confirm that teachers are the most significant school-based factor in improving student achievement, particularly for the…

Properties of the superconductor in accelerator dipole magnets

NASA Astrophysics Data System (ADS)

Teravest, Derk

Several aspects of the application of superconductors to high field dipole magnets for particle accelerators are discussed. The attention is focused on the 10 tesla (1 m model) magnet that is envisaged for the future Large Hadron Collider (LHC) accelerator. The basic motivation behind the study is the intention of employing superconductors to their utmost performance. An overview of practical supercomputers, their applications and their impact on high field dipole magnets used for particle accelerators, is presented. The LHC reference design for the dipole magnets is outlined. Several models were used to study the influence of a number of factors in the shape and in particular, the deviation from the shape that is due to the flux flow state. For the investigated extrinsic and intrinsic factors, a classification can be made with respect to the effect on the shape of the characteristic of a multifilamentary wire. The optimization of the coil structure for high field dipole magnets, with respect to the field quality is described. An analytical model for solid and hollow filaments, to calculate the effect of filament magnetization in the quality of the dipole field, is presented.

Size and shape-dependent cytotoxicity profile of gold nanoparticles for biomedical applications.

PubMed

Woźniak, Anna; Malankowska, Anna; Nowaczyk, Grzegorz; Grześkowiak, Bartosz F; Tuśnio, Karol; Słomski, Ryszard; Zaleska-Medynska, Adriana; Jurga, Stefan

2017-06-01

Metallic nanoparticles, in particular gold nanoparticles (AuNPs), offer a wide spectrum of applications in biomedicine. A crucial issue is their cytotoxicity, which depends greatly on various factors, including morphology of nanoparticles. Because metallic nanoparticles have an effect on cell membrane integrity, their shape and size may affect the viability of cells, due to their different geometries as well as physical and chemical interactions with cell membranes. Variations in the size and shape of gold nanoparticles may indicate particular nanoparticle morphologies that provide strong cytotoxicity effects. Synthesis of different sized and shaped bare AuNPs was performed with spherical (~ 10 nm), nanoflowers (~ 370 nm), nanorods (~ 41 nm), nanoprisms (~ 160 nm) and nanostars (~ 240 nm) morphologies. These nanostructures were characterized and interacting with cancer (HeLa) and normal (HEK293T) cell lines and cell viability tests were performed by WST-1 tests and fluorescent live/dead cell imaging experiments. It was shown that various shapes and sizes of gold nanostructures may affect the viability of the cells. Gold nanospheres and nanorods proved to be more toxic than star, flower and prism gold nanostructures. This may be attributed to their small size and aggregation process. This is the first report concerning a comparison of cytotoxic profile in vitro with a wide spectrum of bare AuNPs morphology. The findings show their possible use in biomedical applications.

Aspheric Solute Ions Modulate Gold Nanoparticle Interactions in an Aqueous Solution: An Optimal Way to Reversibly Concentrate Functionalized Nanoparticles

PubMed Central

Villarreal, Oscar D; Chen, Liao Y; Whetten, Robert L; Demeler, Borries

2015-01-01

Nanometer-sized gold particles (AuNPs) are of peculiar interest because their behaviors in an aqueous solution are sensitive to changes in environmental factors including the size and shape of the solute ions. In order to determine these important characteristics, we performed all-atom molecular dynamics simulations on the icosahedral Au144 nanoparticles each coated with a homogeneous set of 60 thiolates (4-mercapto-benzoate, pMBA) in eight aqueous solutions having ions of varying sizes and shapes (Na+, K+, tetramethylamonium cation TMA+, trisamonium cation TRS+, Cl−, and OH−). For each solution, we computed the reversible work (potential of mean of force) to bring two nanoparticles together as a function of their separation distance. We found that the behavior of pMBA protected Au144 nanoparticles can be readily modulated by tuning their aqueous environmental factors (pH and solute ion combinations). We examined the atomistic details on how the sizes and shapes of solute ions quantitatively factor in the definitive characteristics of nanoparticle-environment and nanoparticle-nanoparticle interactions. We predict that tuning the concentrations of non-spherical composite ions such as TRS+ in an aqueous solution of AuNPs be an effective means to modulate the aggregation propensity desired in biomedical and other applications of small charged nanoparticles. PMID:26581232

Aspheric Solute Ions Modulate Gold Nanoparticle Interactions in an Aqueous Solution: An Optimal Way To Reversibly Concentrate Functionalized Nanoparticles.

PubMed

Villarreal, Oscar D; Chen, Liao Y; Whetten, Robert L; Demeler, Borries

2015-12-17

Nanometer-sized gold particles (AuNPs) are of peculiar interest because their behaviors in an aqueous solution are sensitive to changes in environmental factors including the size and shape of the solute ions. In order to determine these important characteristics, we performed all-atom molecular dynamics simulations on the icosahedral Au144 nanoparticles each coated with a homogeneous set of 60 thiolates (4-mercaptobenzoate, pMBA) in eight aqueous solutions having ions of varying sizes and shapes (Na(+), K(+), tetramethylamonium cation TMA(+), tris-ammonium cation TRS(+), Cl(-), and OH(-)). For each solution, we computed the reversible work (potential of mean of force) to bring two nanoparticles together as a function of their separation distance. We found that the behavior of pMBA protected Au144 nanoparticles can be readily modulated by tuning their aqueous environmental factors (pH and solute ion combinations). We examined the atomistic details on how the sizes and shapes of solute ions quantitatively factor in the definitive characteristics of nanoparticle-environment and nanoparticle-nanoparticle interactions. We predict that tuning the concentrations of nonspherical composite ions such as TRS(+) in an aqueous solution of AuNPs be an effective means to modulate the aggregation propensity desired in biomedical and other applications of small charged nanoparticles.

Central safety factor and β N control on NSTX-U via beam power and plasma boundary shape modification, using TRANSP for closed loop simulations

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

Boyer, M. D.; Andre, R.; Gates, D. A.

The high-performance operational goals of NSTX-U will require development of advanced feedback control algorithms, including control of ßN and the safety factor profile. In this work, a novel approach to simultaneously controlling ßN and the value of the safety factor on the magnetic axis, q0, through manipulation of the plasma boundary shape and total beam power, is proposed. Simulations of the proposed scheme show promising results and motivate future experimental implementation and eventual integration into a more complex current profile control scheme planned to include actuation of individual beam powers, density, and loop voltage. As part of this work, amore » flexible framework for closed loop simulations within the high-fidelity code TRANSP was developed. The framework, used here to identify control-design-oriented models and to tune and test the proposed controller, exploits many of the predictive capabilities of TRANSP and provides a means for performing control calculations based on user-supplied data (controller matrices, target waveforms, etc.). The flexible framework should enable high-fidelity testing of a variety of control algorithms, thereby reducing the amount of expensive experimental time needed to implement new control algorithms on NSTX-U and other devices.« less

Central safety factor and βN control on NSTX-U via beam power and plasma boundary shape modification, using TRANSP for closed loop simulations

NASA Astrophysics Data System (ADS)

Boyer, M. D.; Andre, R.; Gates, D. A.; Gerhardt, S.; Goumiri, I. R.; Menard, J.

2015-05-01

The high-performance operational goals of NSTX-U will require development of advanced feedback control algorithms, including control of βN and the safety factor profile. In this work, a novel approach to simultaneously controlling βN and the value of the safety factor on the magnetic axis, q0, through manipulation of the plasma boundary shape and total beam power, is proposed. Simulations of the proposed scheme show promising results and motivate future experimental implementation and eventual integration into a more complex current profile control scheme planned to include actuation of individual beam powers, density, and loop voltage. As part of this work, a flexible framework for closed loop simulations within the high-fidelity code TRANSP was developed. The framework, used here to identify control-design-oriented models and to tune and test the proposed controller, exploits many of the predictive capabilities of TRANSP and provides a means for performing control calculations based on user-supplied data (controller matrices, target waveforms, etc). The flexible framework should enable high-fidelity testing of a variety of control algorithms, thereby reducing the amount of expensive experimental time needed to implement new control algorithms on NSTX-U and other devices.

Exploring Local Level Factors Shaping the Implementation of a Blended Learning Module for Information and Geospatial Literacy in Ontario

ERIC Educational Resources Information Center

Vine, Michelle M.; Chiappetta-Swanson, Catherine; Maclachlan, John; Brodeur, Jason J.; Bagg, Julianne

2016-01-01

The objectives of this research study were to examine local level factors shaping the implementation of a blended pedagogical approach for geospatial- and information-literacy, and to understand implementer satisfaction. As such, we addressed the following research questions: What local-level factors shape the implementation of the blended…

Clinical relevance of valgus deformity of proximal femur in cerebral palsy.

PubMed

Lee, Kyoung Min; Kang, Jong Yeol; Chung, Chin Youb; Kwon, Dae Gyu; Lee, Sang Hyeong; Choi, In Ho; Cho, Tae-Joon; Yoo, Won Joon; Park, Moon Seok

2010-01-01

Proximal femoral deformity related to physis has not been studied in patients with cerebral palsy (CP). This study was performed to investigate the clinical relevance of neck shaft angle (NSA), head shaft angle (HSA), and proximal femoral epiphyseal shape in patients with CP, which represent the deformities of metaphysis, physis, and epiphysis, respectively. Three hundred eighty-four patients with CP (mean age 9.1 y, 249 males and 135 females) were included. Extent of involvement and functional states [Gross Motor Function Classification System (GMFCS) level] were obtained. Radiographic measurements including NSA, HSA, and qualitative shape of the proximal femoral epiphysis were evaluated and analyzed according to extent of involvement and GMFCS level. Reliability and correlation with each measurement were assessed. Multiple regression test was performed to examine the significant contributing factors to migration percentage (MP) that represents hip instability. NSA showed excellent interobserver reliability with intraclass correlation coefficients of 0.976. Correlation with the MP was higher in the NSA (r=0.419, P<0.001) than in the HSA (r=0.256, P<0.001). NSA, HSA, and MP tended to increase with increasing GMFCS level, and proportion of valgus deformed proximal femoral epiphysis also increased with increasing GMFCS level, which means valgus deformity and unstable hips in the less favorable functional states. Multiple regression analysis revealed NSA, GMFCS level, and shape of the proximal femoral epiphysis to be significant factors affecting MP. NSA appeared to be more clinically relevant than HSA in evaluating proximal femoral deformity in patients with CP. Shape of proximal femoral epiphysis is believed to have clinical implications in terms of hip instability. Diagnostic level II.

Stability Analysis of High-Speed Boundary-Layer Flow with Gas Injection

DTIC Science & Technology

2014-06-01

Vitaly G. Soudakov; Ivett A Leyva 5e. TASK NUMBER 5f. WORK UNIT NUMBER Q0AF 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING...cases of low injection rates in which the N -factors in the near field region are below the critical level, shaping can produce a significant...distribution unlimited Stability analysis of high-speed boundary-layer flow with gas injection Alexander V. Fedorov* and Vitaly G. Soudakov

Stability Analysis of High-Speed Boundary-Layer Flow with Gas Injection (Briefing Charts)

DTIC Science & Technology

2014-06-01

Vitaly G. Soudakov; Ivett A Leyva 5e. TASK NUMBER 5f. WORK UNIT NUMBER Q0AF 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING...cases of low injection rates in which the N -factors in the near field region are below the critical level, shaping can produce a significant...Release; Distribution Unlimited Stability analysis of high-speed boundary-layer flow with gas injection Alexander Fedorov and Vitaly Soudakov Moscow

Double resonance calibration of g factor standards: Carbon fibers as a high precision standard

NASA Astrophysics Data System (ADS)

Herb, Konstantin; Tschaggelar, Rene; Denninger, Gert; Jeschke, Gunnar

2018-04-01

The g factor of paramagnetic defects in commercial high performance carbon fibers was determined by a double resonance experiment based on the Overhauser shift due to hyperfine coupled protons. Our carbon fibers exhibit a single, narrow and perfectly Lorentzian shaped ESR line and a g factor slightly higher than gfree with g = 2.002644 =gfree · (1 + 162ppm) with a relative uncertainty of 15ppm . This precisely known g factor and their inertness qualify them as a high precision g factor standard for general purposes. The double resonance experiment for calibration is applicable to other potential standards with a hyperfine interaction averaged by a process with very short correlation time.

Printable Solid-State Lithium-Ion Batteries: A New Route toward Shape-Conformable Power Sources with Aesthetic Versatility for Flexible Electronics.

PubMed

Kim, Se-Hee; Choi, Keun-Ho; Cho, Sung-Ju; Choi, Sinho; Park, Soojin; Lee, Sang-Young

2015-08-12

Forthcoming flexible/wearable electronic devices with shape diversity and mobile usability garner a great deal of attention as an innovative technology to bring unprecedented changes in our daily lives. From the power source point of view, conventional rechargeable batteries (one representative example is a lithium-ion battery) with fixed shapes and sizes have intrinsic limitations in fulfilling design/performance requirements for the flexible/wearable electronics. Here, as a facile and efficient strategy to address this formidable challenge, we demonstrate a new class of printable solid-state batteries (referred to as "PRISS batteries"). Through simple stencil printing process (followed by ultraviolet (UV) cross-linking), solid-state composite electrolyte (SCE) layer and SCE matrix-embedded electrodes are consecutively printed on arbitrary objects of complex geometries, eventually leading to fully integrated, multilayer-structured PRISS batteries with various form factors far beyond those achievable by conventional battery technologies. Tuning rheological properties of SCE paste and electrode slurry toward thixotropic fluid characteristics, along with well-tailored core elements including UV-cured triacrylate polymer and high boiling point electrolyte, is a key-enabling technology for the realization of PRISS batteries. This process/material uniqueness allows us to remove extra processing steps (related to solvent drying and liquid-electrolyte injection) and also conventional microporous separator membranes, thereupon enabling the seamless integration of shape-conformable PRISS batteries (including letters-shaped ones) into complex-shaped objects. Electrochemical behavior of PRISS batteries is elucidated via an in-depth analysis of cell impedance, which provides a theoretical basis to enable sustainable improvement of cell performance. We envision that PRISS batteries hold great promise as a reliable and scalable platform technology to open a new concept of cell architecture and fabrication route toward flexible power sources with exceptional shape conformability and aesthetic versatility.

Performance-Shaping Factors Affecting Older Adults' Hospital-to-Home Transition Success: A Systems Approach.

PubMed

Werner, Nicole E; Tong, Michelle; Borkenhagen, Amy; Holden, Richard J

2018-01-03

Facilitating older adults' successful hospital-to-home transitions remains a persistent challenge. To address this challenge, we applied a systems lens to identify and understand the performance-shaping factors (PSFs) related older adults' hospital-to-home transition success. This study was a secondary analysis of semi-structured interviews from older adults (N = 31) recently discharged from a hospital and their informal caregivers (N = 13). We used a Human Factors Engineering approach to guide qualitative thematic analysis to develop four themes concerning the system conditions shaping hospital-to-home transition success. The four themes concerning PSFs were: (a) the hospital-to-home transition was a complex multiphase process-the process unfolded over several months and required substantial, persistent investment/effort; (b) there were unmet needs for specialized tools-information and resources provided at hospital discharge were not aligned with requirements for transition success; (c) alignment of self-care routines with transition needs-pre-hospitalization routines could be supportive/disruptive and could deteriorate/be re-established; and (d) changing levels of work demand and capacity during the transition-demand often exceeded capacity leading to work overload. Our findings highlight that the transition is not an episodic event, but rather a longitudinal process extending beyond the days just after hospital discharge. Transition interventions to improve older adults' hospital-to-home transitions need to account for this complex multiphase process. Future interventions must be developed to support older adults and informal caregivers in navigating the establishment and re-establishment of routines and managing work demands and capacity during the transition process. © The Author(s) 2018. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The relative use of proximity, shape similarity, and orientation as visual perceptual grouping cues in tufted capuchin monkeys (Cebus apella) and humans (Homo sapiens).

PubMed

Spinozzi, Giovanna; De Lillo, Carlo; Truppa, Valentina; Castorina, Giulia

2009-02-01

Recent experimental results suggest that human and nonhuman primates differ in how they process visual information to assemble component parts into global shapes. To assess whether some of the observed differences in perceptual grouping could be accounted for by the prevalence of different grouping factors in different species, we carried out 2 experiments designed to evaluate the relative use of proximity, similarity of shape, and orientation as grouping cues in humans (Homo sapiens) and capuchin monkeys (Cebus apella). Both species showed similarly high levels of accuracy using proximity as a cue. Moreover, for both species, grouping by orientation similarity produced a lower level of performance than grouping by proximity. Differences emerged with respect to the use of shape similarity as a cue. In humans, grouping by shape similarity also proved less effective than grouping by proximity but the same was not observed in capuchins. These results suggest that there may be subtle differences between humans and capuchin monkeys in the weighting assigned to different grouping cues that may affect the way in which they combine local features into global shapes. Copyright 2009 APA, all rights reserved.

Membrane wrinkling patterns and control with SMA and SMPC actuators

NASA Astrophysics Data System (ADS)

Lu, Mingyu; Li, Yunliang; Tan, Huifeng; Zhou, Limin

2009-07-01

Wrinkling is a main factor affecting the performance of the membrane structures and is always considered to be a failure as it can cause dramatic decrease of shape accuracy. The study of membrane wrinkling control has the analytical and experimental meanings. In this paper, a feasible membrane shape control method is presented. An expression of wrinkle wavelength using stress extremum principle is established based on the tension field theory and the Von Karman large deflection formula which verifies the generation and evolution reason of membrane wrinkles. The control mechanism for membrane wrinkles is developed using shape memory alloy (SMA) and shape memory polymer composite (SMPC) actuators which are attached to the boundaries of the membrane for producing contraction/expansion forces to adjust the shape of the membrane. The whole control process is monitored by photogrammetric technique. Numerical simulations are also conducted using ANSYS finite element software with the nonlinear post-buckling analytical method. Both the experimental and numerical results show that the amplitudes of wrinkles are effectively controlled by SMA and SMPC actuators. The method introduced in this paper provides the foundation for shape control of the membrane wrinkling and is important to the future work on vibration control of space membrane structures.

Actuation of a robotic fish caudal fin for low reaction torque

NASA Astrophysics Data System (ADS)

Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghee

2011-07-01

In this paper, a novel caudal fin for actuating a robotic fish is presented. The proposed caudal fin waves in a vertical direction with a specific spatial shape, which is determined by a so-called shape factor. For a specific shape factor, a traveling wave with a vertical phase difference is formed on a caudal fin during fin motion. It will be shown by the analysis that the maximum reaction torque at the joint of a caudal fin varies depending on the shape factors. Compared with a conventional plate type caudal fin, the proposed fin with a shape factor of 2π can eliminate the reaction torque perfectly, while keeping the propulsion force unchanged. The benefits of the proposed fin will be demonstrated by experiments.

Environmental effects on the shape variation of male ultraviolet patterns in the Brimstone butterfly ( Gonepteryx rhamni, Pieridae, Lepidoptera)

NASA Astrophysics Data System (ADS)

Pecháček, Pavel; Stella, David; Keil, Petr; Kleisner, Karel

2014-12-01

The males of the Brimstone butterfly ( Gonepteryx rhamni) have ultraviolet pattern on the dorsal surfaces of their wings. Using geometric morphometrics, we have analysed correlations between environmental variables (climate, productivity) and shape variability of the ultraviolet pattern and the forewing in 110 male specimens of G. rhamni collected in the Palaearctic zone. To start with, we subjected the environmental variables to principal component analysis (PCA). The first PCA axis (precipitation, temperature, latitude) significantly correlated with shape variation of the ultraviolet patterns across the Palaearctic. Additionally, we have performed two-block partial least squares (PLS) analysis to assess co-variation between intraspecific shape variation and the variation of 11 environmental variables. The first PLS axis explained 93 % of variability and represented the effect of precipitation, temperature and latitude. Along this axis, we observed a systematic increase in the relative area of ultraviolet colouration with increasing temperature and precipitation and decreasing latitude. We conclude that the shape variation of ultraviolet patterns on the forewings of male Brimstones is correlated with large-scale environmental factors.

Experimental investigation of the effect of variously-shaped ribs on local heat transfer on the outer wall of the turning portion of a U-channel inside solar air heater

NASA Astrophysics Data System (ADS)

Salameh, Tareq; Alami, Abdul Hai; Sunden, Bengt

2016-03-01

In the present work, an experimental investigation of convective heat transfer and pressure drop was carried out for the turning portion of a U-channel where the outer wall was equipped with ribs. The shape of the ribs was varied. The investigation aims to give guidelines for improving the thermo-hydraulic performance of a solar air heater at the turning portion of a U-channel. Both the U-channel and the ribs were made in acrylic material to allow optical access for measuring the surface temperature by using a high-resolution technique based on narrow band thermochromic liquid crystals (TLC R35C5 W) and a CCD camera placed to face the turning portion of the U-channel. The uncertainties were estimated to 5 and 7 % for the Nusselt number and friction factor, respectively. The pressure drop was approximately the same for all the considered shapes of the ribs while the dimpled rib case gave the highest heat transfer coefficient while the grooved rib presented the highest performance index.

Addressing Elementary School Teachers' Professional Stressors: Practical Suggestions for Schools and Administrators

ERIC Educational Resources Information Center

Stauffer, Sarah D.; Mason, Erin C. M.

2013-01-01

Purpose: Given the preponderance of education reform since the No Child Left Behind Act (U.S. Department of Education, 2001), reform efforts have shaped the nature of the work and culture in schools. The emphasis on standardized testing to determine schools' status and student performance, among other factors, has generated stress, particularly…

Quality of the log-geometric distribution extrapolation for smaller undiscovered oil and gas pool size

USGS Publications Warehouse

Chenglin, L.; Charpentier, R.R.

2010-01-01

The U.S. Geological Survey procedure for the estimation of the general form of the parent distribution requires that the parameters of the log-geometric distribution be calculated and analyzed for the sensitivity of these parameters to different conditions. In this study, we derive the shape factor of a log-geometric distribution from the ratio of frequencies between adjacent bins. The shape factor has a log straight-line relationship with the ratio of frequencies. Additionally, the calculation equations of a ratio of the mean size to the lower size-class boundary are deduced. For a specific log-geometric distribution, we find that the ratio of the mean size to the lower size-class boundary is the same. We apply our analysis to simulations based on oil and gas pool distributions from four petroleum systems of Alberta, Canada and four generated distributions. Each petroleum system in Alberta has a different shape factor. Generally, the shape factors in the four petroleum systems stabilize with the increase of discovered pool numbers. For a log-geometric distribution, the shape factor becomes stable when discovered pool numbers exceed 50 and the shape factor is influenced by the exploration efficiency when the exploration efficiency is less than 1. The simulation results show that calculated shape factors increase with those of the parent distributions, and undiscovered oil and gas resources estimated through the log-geometric distribution extrapolation are smaller than the actual values. ?? 2010 International Association for Mathematical Geology.

Shaping nursing profession regulation through history - a systematic review.

PubMed

Stievano, A; Caruso, R; Pittella, F; Shaffer, F A; Rocco, G; Fairman, J

2018-03-23

The aim of this systematic review was to provide a critical synthesis of the factors that historically shaped the advancements of nursing regulators worldwide. An in-depth examination of the different factors that moulded regulatory changes over time is pivotal to comprehend current issues in nursing. In the light of global health scenarios, the researchers explored the factors that historically influenced the socio-contextual circumstances upon which governments made regulatory changes. A systematic search was performed on the following databases: PubMed, CINAHL, Scopus, OpenGrey and ScienceDirect. The review included papers from January 2000 to October 2016 published in English. The authors used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and an inductive thematic approach for synthesis. Two main themes were identified: factors underpinning current challenges and historical and contextual triggers of regulation. The first theme was composed of three aspects: education, migration and internationalization, and policy and regulation; the second theme consisted of four attributes: demographics, economics, history of registration and wars, and historical changes in nursing practice. Factors that shaped nursing regulation were linked to changing demographics and economics, education, history of nursing registration, shifting patterns of migration and internationalization, nursing practice, policy and regulation and significant societal turns often prompted by wars. A deeper understanding of the developments of the nursing regulatory institutions provides the foundation for portable standards that can be applied across an array of jurisdictions to guarantee a better public safety. Understanding factors that socially, legislatively and politically have influenced the development of regulatory bodies over time helps to mould local, national and international policies that have a stronger impact on health worldwide. To achieve this, there must be effective cooperation among systems of nursing regulations globally. © 2018 International Council of Nurses.

Shape effects on the electronic structure and the optical gain of InAsN/GaAs nanostructures: From a quantum lens to a quantum ring

NASA Astrophysics Data System (ADS)

Chen, J.; Fan, W. J.; Xu, Q.; Zhang, X. W.; Li, S. S.; Xia, J. B.

2012-10-01

The electronic structures of self-assembled InAs1-xNx/GaAs nanostructures from quantum lens to quantum rings (QRs) are calculated using the 10-band k.p method and the valence force field (VFF) method. With the variation of shape of the nanostructure and nitrogen (N) content, it shows that the N and the strains can significantly affect the energy levels especially the conduction band because the N resonant state has repulsion interaction with the conduction band due to the band anticrossing (BAC). The structures with N and greater height have smaller transition energy, and the structures with N have greater optical gain due to its overwhelming greater value of factor f+f-1. After analyzing the shape effect, we suggested that the nanostructures with volcano shape are preferred because the maximum optical gain occurs for quantum volcano. With our simulation result, researchers could select quantum dots (QDs) structures to design laser with better performance.

The Nazi cosmetic: medicine in the service of beauty.

PubMed

Efstathiou, Sophia

2012-09-01

This paper examines how aesthetic ideals shaped the practice of Nazi medicine. It proposes that Nazi eugenics relied on the conflation of norms of health with norms of beauty determined and performed by Nazi cultures of action. Though theories of biological holism served as vehicles of Nazi ideology, they did so contingently. The anti-totalitarian thinking of biological holist Kurt Goldstein shows that the use of biological holism to promote Nazi ideology was not inevitable. This examination of aesthetic influences on Nazi medicine shows that traditionally speaking 'non-rational' factors shaped the Nazi biomedical program's aims and methods. Copyright © 2012 Elsevier Ltd. All rights reserved.

Quadrupolar asymmetry in shifted-stem vane-shaped-rod radio frequency quadrupole accelerator

NASA Astrophysics Data System (ADS)

Mehrotra, Nitin

2018-04-01

Quadrupolar Asymmetry (QA), which has been a rampant problem for rod-type Radio Frequency Quadrupole (RFQ) Linacs, arises due to the geometry of resonant structure. A systematic parametric simulation study has been performed to unravel their effect on Figure of Merit (FoM) quantities namely Quality Factor (Q), Shunt Impedance (Rsh) and Quadrupolar Asymmetry (QA). A novel stem and cavity shape is proposed, which caters to the profile of electromagnetic fields of the resonant structure. A design methodology is formulated, which demonstrates that Quadrupolar Asymmetry can be annihilated, and a symmetric electric field can be produced in all four quadrants of rod-type RFQ accelerator.

The relationship between hand anthropometrics, total grip strength and individual finger force for various handle shapes.

PubMed

Kong, Yong-Ku; Kim, Dae-Min

2015-01-01

The design and shape of hand tool handles are critical factors for preventing musculoskeletal disorders (MSDs) caused by the use of hand tools. We explored how these factors are related to total force and individual finger force in males and females with various hand anthropometrics. Using the MFFM system, we assessed four indices of anthropometry, and measured total force and individual finger force on various handle designs and shapes. Both total force and individual finger force were significant according to gender and handle shape. Total grip strength to the handle shape indicated the greatest strength with D shape and the least with A shape. From the regression analysis of hand anthropometric indices, the value of R was respectably high at 0.608-0.696. The current study examined the gender and handle shape factors affecting grip strength based on the force measurements from various handle types, in terms of influence on different hand anthropometric indices.

Development of Control Models and a Robust Multivariable Controller for Surface Shape Control

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

Winters, Scott Eric

2003-06-18

Surface shape control techniques are applied to many diverse disciplines, such as adaptive optics, noise control, aircraft flutter control and satellites, with an objective to achieve a desirable shape for an elastic body by the application of distributed control forces. Achieving the desirable shape is influenced by many factors, such as, actuator locations, sensor locations, surface precision and controller performance. Building prototypes to complete design optimizations or controller development can be costly or impractical. This shortfall, puts significant value in developing accurate modeling and control simulation approaches. This thesis focuses on the field of adaptive optics, although these developments havemore » the potential for application in many other fields. A static finite element model is developed and validated using a large aperture interferometer system. This model is then integrated into a control model using a linear least squares algorithm and Shack-Hartmann sensor. The model is successfully exercised showing functionality for various wavefront aberrations. Utilizing a verified model shows significant value in simulating static surface shape control problems with quantifiable uncertainties. A new dynamic model for a seven actuator deformable mirror is presented and its accuracy is proven through experiment. Bond graph techniques are used to generate the state space model of the multi-actuator deformable mirror including piezo-electric actuator dynamics. Using this verified model, a robust multi-input multi-output (MIMO) H ∞ controller is designed and implemented. This controller proved superior performance as compared to a standard proportional-integral controller (PI) design.« less

Capillary-tube-based extension of thermoacoustic theory for a random medium

NASA Astrophysics Data System (ADS)

Roh, Heui-Seol; Raspet, Richard; Bass, Henry E.

2005-09-01

Thermoacoustic theory for a single capillary tube is extended to random bulk medium on the basis of capillary tubes. The characteristics of the porous stack inside the resonator such as the tortuosity, dynamic shape factor, and porosity are introduced for the extension of wave equation by following Attenborough's approach. Separation of the dynamic shape factor for the viscous and thermal effect is adopted and scaling using the dynamic shape factor and tortuosity factor is demonstrated. The theoretical and experimental comparison of thermoviscous functions in reticulated vitreous carbon (RVC) and aluminum foam shows reasonable agreement. The extension is useful for investigations of the properties of a stack with arbitrary shapes of non-parallel pores.

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

Dustin Popp; Zander Mausolff; Sedat Goluoglu

We are proposing to use the code, TDKENO, to model TREAT. TDKENO solves the time dependent, three dimensional Boltzmann transport equation with explicit representation of delayed neutrons. Instead of directly integrating this equation, the neutron flux is factored into two components – a rapidly varying amplitude equation and a slowly varying shape equation and each is solved separately on different time scales. The shape equation is solved using the 3D Monte Carlo transport code KENO, from Oak Ridge National Laboratory’s SCALE code package. Using the Monte Carlo method to solve the shape equation is still computationally intensive, but the operationmore » is only performed when needed. The amplitude equation is solved deterministically and frequently, so the solution gives an accurate time-dependent solution without having to repeatedly We have modified TDKENO to incorporate KENO-VI so that we may accurately represent the geometries within TREAT. This paper explains the motivation behind using generalized geometry, and provides the results of our modifications. TDKENO uses the Improved Quasi-Static method to accomplish this. In this method, the neutron flux is factored into two components. One component is a purely time-dependent and rapidly varying amplitude function, which is solved deterministically and very frequently (small time steps). The other is a slowly varying flux shape function that weakly depends on time and is only solved when needed (significantly larger time steps).« less

The influence of hand positions on biomechanical injury risk factors at the wrist joint during the round-off skills in female gymnastics.

PubMed

Farana, Roman; Jandacka, Daniel; Uchytil, Jaroslav; Zahradnik, David; Irwin, Gareth

2017-01-01

The aim of this study was to examine the biomechanical injury risk factors at the wrist, including joint kinetics, kinematics and stiffness in the first and second contact limb for parallel and T-shape round-off (RO) techniques. Seven international-level female gymnasts performed 10 trials of the RO to back handspring with parallel and T-shape hand positions. Synchronised kinematic (3D motion analysis system; 247 Hz) and kinetic (two force plates; 1235 Hz) data were collected for each trial. A two-way repeated measure analysis of variance (ANOVA) assessed differences in the kinematic and kinetic parameters between the techniques for each contact limb. The main findings highlighted that in both the RO techniques, the second contact limb wrist joint is exposed to higher mechanical loads than the first contact limb demonstrated by increased axial compression force and loading rate. In the parallel technique, the second contact limb wrist joint is exposed to higher axial compression load. Differences between wrist joint kinetics highlight that the T-shape technique may potentially lead to reducing these bio-physical loads and consequently protect the second contact limb wrist joint from overload and biological failure. Highlighting the biomechanical risk factors facilitates the process of technique selection making more objective and safe.

Environmental factors that shape biofilm formation.

PubMed

Toyofuku, Masanori; Inaba, Tomohiro; Kiyokawa, Tatsunori; Obana, Nozomu; Yawata, Yutaka; Nomura, Nobuhiko

2016-01-01

Cells respond to the environment and alter gene expression. Recent studies have revealed the social aspects of bacterial life, such as biofilm formation. Biofilm formation is largely affected by the environment, and the mechanisms by which the gene expression of individual cells affects biofilm development have attracted interest. Environmental factors determine the cell's decision to form or leave a biofilm. In addition, the biofilm structure largely depends on the environment, implying that biofilms are shaped to adapt to local conditions. Second messengers such as cAMP and c-di-GMP are key factors that link environmental factors with gene regulation. Cell-to-cell communication is also an important factor in shaping the biofilm. In this short review, we will introduce the basics of biofilm formation and further discuss environmental factors that shape biofilm formation. Finally, the state-of-the-art tools that allow us investigate biofilms under various conditions are discussed.

S-EMG signal compression based on domain transformation and spectral shape dynamic bit allocation

PubMed Central

2014-01-01

Background Surface electromyographic (S-EMG) signal processing has been emerging in the past few years due to its non-invasive assessment of muscle function and structure and because of the fast growing rate of digital technology which brings about new solutions and applications. Factors such as sampling rate, quantization word length, number of channels and experiment duration can lead to a potentially large volume of data. Efficient transmission and/or storage of S-EMG signals are actually a research issue. That is the aim of this work. Methods This paper presents an algorithm for the data compression of surface electromyographic (S-EMG) signals recorded during isometric contractions protocol and during dynamic experimental protocols such as the cycling activity. The proposed algorithm is based on discrete wavelet transform to proceed spectral decomposition and de-correlation, on a dynamic bit allocation procedure to code the wavelets transformed coefficients, and on an entropy coding to minimize the remaining redundancy and to pack all data. The bit allocation scheme is based on mathematical decreasing spectral shape models, which indicates a shorter digital word length to code high frequency wavelets transformed coefficients. Four bit allocation spectral shape methods were implemented and compared: decreasing exponential spectral shape, decreasing linear spectral shape, decreasing square-root spectral shape and rotated hyperbolic tangent spectral shape. Results The proposed method is demonstrated and evaluated for an isometric protocol and for a dynamic protocol using a real S-EMG signal data bank. Objective performance evaluations metrics are presented. In addition, comparisons with other encoders proposed in scientific literature are shown. Conclusions The decreasing bit allocation shape applied to the quantized wavelet coefficients combined with arithmetic coding results is an efficient procedure. The performance comparisons of the proposed S-EMG data compression algorithm with the established techniques found in scientific literature have shown promising results. PMID:24571620

Eye shape using partial coherence interferometry, autorefraction, and SD-OCT.

PubMed

Clark, Christopher A; Elsner, Ann E; Konynenbelt, Benjamin J

2015-01-01

Peripheral refraction and retinal shape may influence refractive development. Peripheral refraction has been shown to have a high degree of variability and can take considerable time to perform. Spectral domain optical coherence tomography (SD-OCT) and peripheral axial length measures may be more reliable, assuming that the retinal position is more important than the peripheral optics of the lens/cornea. Seventy-nine subjects' right eyes were imaged for this study (age range, 22 to 34 years; refractive error, -10 to +5.00). Thirty-degree SD-OCT (Spectralis, Heidelberg Engineering, Heidelberg, Germany) images were collected in a radial pattern along with peripheral refraction with an autorefractor (Shin-Nippon Autorefractor) and peripheral axial length measurements with partial coherence interferometry (IOLMaster, Zeiss). Statistics were performed using repeated-measures analysis of variance in SPSS (IBM, Armonk, NY), Bland-Altman analyses, and regression. All measures were converted to diopters to allow direct comparison. Spectral domain OCT showed a retinal shape with an increased curvature for myopes compared with emmetropes/hyperopes. This retinal shape change became significant around 5 degrees. The SD-OCT analysis for retinal shape provides a resolution of 0.026 diopters, which is about 10 times more accurate than using autorefraction (AR) or clinical refractive techniques. Bland-Altman analyses suggest that retinal shape measured by SD-OCT and the partial coherence interferometry method were more consistent with one another than either was with AR. With more accurate measures of retinal shape using SD-OCT, consistent differences between emmetropes/hyperopes and myopes were found nearer to the fovea than previously reported. Retinal shape may be influenced by central refractive error, and not merely peripheral optics. Partial coherence interferometry and SD-OCT appear to be more accurate than AR, which may be influenced by other factors such as fixation and accommodation. Autorefraction does measure the optics directly, which may be a strength of that method.

European Responses to Global Competitiveness in Higher Education. Research & Occasional Paper Series: CSHE.7.09

ERIC Educational Resources Information Center

van der Wende, Marijk

2009-01-01

The growing global competition in which knowledge is a prime factor for economic growth is increasingly shaping policies and setting the agenda for the future of European higher education. With its aim to become the world's leading knowledge economy, the European Union is concerned about its performance in the knowledge sector, in particular in…

"It's Like Spiderman … with Great Power Comes Great Responsibility": School Autonomy, School Context and the Audit Culture

ERIC Educational Resources Information Center

Keddie, Amanda

2014-01-01

This paper explores issues of school autonomy within the context of the performative demands of the audit culture. The focus is on a case study of Clementine Academy, a large and highly diverse English secondary school. Specific situated, professional, material and external factors at the school were significant in shaping Clementine's response to…

Lessons along the Cultural Spectrum: Educators Can Build on the Variety of Cultures and Daily Experiences to Shape Students' Learning and Development

ERIC Educational Resources Information Center

Williams, Belinda

2006-01-01

Although economically disadvantaged and minority students made some gains in their academic achievement performance, education reforms still fail to close the academic achievement gap between them. A discussion of the factors that influence the achievement gap is presented and provides some professional development implications. According to the…

A Mid-Layer Model for Human Reliability Analysis: Understanding the Cognitive Causes of Human Failure Events

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

Stacey M. L. Hendrickson; April M. Whaley; Ronald L. Boring

The Office of Nuclear Regulatory Research (RES) is sponsoring work in response to a Staff Requirements Memorandum (SRM) directing an effort to establish a single human reliability analysis (HRA) method for the agency or guidance for the use of multiple methods. As part of this effort an attempt to develop a comprehensive HRA qualitative approach is being pursued. This paper presents a draft of the method’s middle layer, a part of the qualitative analysis phase that links failure mechanisms to performance shaping factors. Starting with a Crew Response Tree (CRT) that has identified human failure events, analysts identify potential failuremore » mechanisms using the mid-layer model. The mid-layer model presented in this paper traces the identification of the failure mechanisms using the Information-Diagnosis/Decision-Action (IDA) model and cognitive models from the psychological literature. Each failure mechanism is grouped according to a phase of IDA. Under each phase of IDA, the cognitive models help identify the relevant performance shaping factors for the failure mechanism. The use of IDA and cognitive models can be traced through fault trees, which provide a detailed complement to the CRT.« less

A mid-layer model for human reliability analysis : understanding the cognitive causes of human failure events.

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

Shen, Song-Hua; Chang, James Y. H.; Boring,Ronald L.

2010-03-01

The Office of Nuclear Regulatory Research (RES) at the US Nuclear Regulatory Commission (USNRC) is sponsoring work in response to a Staff Requirements Memorandum (SRM) directing an effort to establish a single human reliability analysis (HRA) method for the agency or guidance for the use of multiple methods. As part of this effort an attempt to develop a comprehensive HRA qualitative approach is being pursued. This paper presents a draft of the method's middle layer, a part of the qualitative analysis phase that links failure mechanisms to performance shaping factors. Starting with a Crew Response Tree (CRT) that has identifiedmore » human failure events, analysts identify potential failure mechanisms using the mid-layer model. The mid-layer model presented in this paper traces the identification of the failure mechanisms using the Information-Diagnosis/Decision-Action (IDA) model and cognitive models from the psychological literature. Each failure mechanism is grouped according to a phase of IDA. Under each phase of IDA, the cognitive models help identify the relevant performance shaping factors for the failure mechanism. The use of IDA and cognitive models can be traced through fault trees, which provide a detailed complement to the CRT.« less

Measurement of Size-dependent Dynamic Shape Factors of Quartz Particles in Two Flow Regimes

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

Alexander, Jennifer M.; Bell, David M.; Imre, D.

2016-08-02

Understanding and modeling the behavior of quartz dust particles, commonly found in the atmosphere, requires knowledge of many relevant particles properties, including particle shape. This study uses a single particle mass spectrometer, a differential mobility analyzer, and an aerosol particle mass analyzer to measure quartz aerosol particles mobility, aerodynamic, and volume equivalent diameters, mass, composition, effective density, and dynamic shape factor as a function of particle size, in both the free molecular and transition flow regimes. The results clearly demonstrate that dynamic shape factors can vary significantly as a function of particle size. For the quartz samples studied here, themore » dynamic shape factors increase with size, indicating that larger particles are significantly more aspherical than smaller particles. In addition, dynamic shape factors measured in the free-molecular (χv) and transition (χt) flow regimes can be significantly different, and these differences vary with the size of the quartz particles. For quartz, χv of small (d < 200 nm) particles is 1.25, while χv of larger particles (d ~ 440 nm) is 1.6, with a continuously increasing trend with particle size. In contrast χt, of small particles starts at 1.1 increasing slowly to 1.34 for 550 nm diameter particles. The multidimensional particle characterization approach used here goes beyond determination of average properties for each size, to provide additional information about how the particle dynamic shape factor may vary even for particles with the same mass and volume equivalent diameter.« less

Low and high speed propellers for general aviation: Performance potential and recent wind tunnel test results

NASA Technical Reports Server (NTRS)

Jeracki, R. J.; Mitchell, G. A.

1981-01-01

The performance of lower speed, 5 foot diameter model general aviation propellers, was tested in the Lewis wind tunnel. Performance was evaluated for various levels of airfoil technology and activity factor. The difference was associated with inadequate modeling of blade and spinner losses for propellers round shank blade designs. Suggested concepts for improvement are: (1) advanced blade shapes (airfoils and sweep); (2) tip devices (proplets); (3) integrated propeller/nacelles; and (4) composites. Several advanced aerodynamic concepts were evaluated in the Lewis wind tunnel. Results show that high propeller performance can be obtained to at least Mach 0.8.

Selection Shapes Transcriptional Logic and Regulatory Specialization in Genetic Networks.

PubMed

Fogelmark, Karl; Peterson, Carsten; Troein, Carl

2016-01-01

Living organisms need to regulate their gene expression in response to environmental signals and internal cues. This is a computational task where genes act as logic gates that connect to form transcriptional networks, which are shaped at all scales by evolution. Large-scale mutations such as gene duplications and deletions add and remove network components, whereas smaller mutations alter the connections between them. Selection determines what mutations are accepted, but its importance for shaping the resulting networks has been debated. To investigate the effects of selection in the shaping of transcriptional networks, we derive transcriptional logic from a combinatorially powerful yet tractable model of the binding between DNA and transcription factors. By evolving the resulting networks based on their ability to function as either a simple decision system or a circadian clock, we obtain information on the regulation and logic rules encoded in functional transcriptional networks. Comparisons are made between networks evolved for different functions, as well as with structurally equivalent but non-functional (neutrally evolved) networks, and predictions are validated against the transcriptional network of E. coli. We find that the logic rules governing gene expression depend on the function performed by the network. Unlike the decision systems, the circadian clocks show strong cooperative binding and negative regulation, which achieves tight temporal control of gene expression. Furthermore, we find that transcription factors act preferentially as either activators or repressors, both when binding multiple sites for a single target gene and globally in the transcriptional networks. This separation into positive and negative regulators requires gene duplications, which highlights the interplay between mutation and selection in shaping the transcriptional networks.

Sensitivity analysis of a ground-water-flow model

USGS Publications Warehouse

Torak, Lynn J.; ,

1991-01-01

A sensitivity analysis was performed on 18 hydrological factors affecting steady-state groundwater flow in the Upper Floridan aquifer near Albany, southwestern Georgia. Computations were based on a calibrated, two-dimensional, finite-element digital model of the stream-aquifer system and the corresponding data inputs. Flow-system sensitivity was analyzed by computing water-level residuals obtained from simulations involving individual changes to each hydrological factor. Hydrological factors to which computed water levels were most sensitive were those that produced the largest change in the sum-of-squares of residuals for the smallest change in factor value. Plots of the sum-of-squares of residuals against multiplier or additive values that effect change in the hydrological factors are used to evaluate the influence of each factor on the simulated flow system. The shapes of these 'sensitivity curves' indicate the importance of each hydrological factor to the flow system. Because the sensitivity analysis can be performed during the preliminary phase of a water-resource investigation, it can be used to identify the types of hydrological data required to accurately characterize the flow system prior to collecting additional data or making management decisions.

Wind tunnel testing of low-drag airfoils

NASA Technical Reports Server (NTRS)

Harvey, W. Donald; Mcghee, R. J.; Harris, C. D.

1986-01-01

Results are presented for the measured performance recently obtained on several airfoil concepts designed to achieve low drag by maintaining extensive regions of laminar flow without compromising high-lift performance. The wind tunnel results extend from subsonic to transonic speeds and include boundary-layer control through shaping and suction. The research was conducted in the NASA Langley 8-Ft Transonic Pressure Tunnel (TPT) and Low Turbulence Pressure Tunnel (LTPT) which have been developed for testing such low-drag airfoils. Emphasis is placed on identifying some of the major factors influencing the anticipated performance of low-drag airfoils.

Analyses and Comparison of Solar Air Heater with Various Rib Roughness using Computational Fluid Dynamics (CFD)

NASA Astrophysics Data System (ADS)

Kumar, K. Ravi; Cheepu, Muralimohan; Srinivas, B.; Venkateswarlu, D.; Pramod Kumar, G.; Shiva, Apireddi

2018-03-01

In solar air heater, artificial roughness on absorber plate become prominent technique to improving heat transfer rate of air flowing passage as a result of laminar sublayer. The selection of rib geometries plays important role on friction characteristics and heat transfer rate. Many researchers studying the roughness shapes over the years to investigate the effect of geometries on the performance of friction factor and heat transfer of the solar air heater. The present study made an attempt to develop the different rib shapes utilised for creating artificial rib roughness and its comparison to investigate higher performance of the geometries. The use of computational fluid dynamics software resulted in correlation of friction factor and heat transfer rate. The simulations studies were performed on 2D computational fluid dynamics model and analysed to identify the most effective parameters of relative roughness of the height, width and pitch on major considerations of friction factor and heat transfer. The Reynolds number is varied in a range from 3000 to 20000, in the current study and modelling has conducted on heat transfer and turbulence phenomena by using Reynolds number. The modelling results showed the formation of strong vortex in the main stream flow due to the right angle triangle roughness over the square, rectangle, improved rectangle and equilateral triangle geometries enhanced the heat transfer extension in the solar air heater. The simulation of the turbulence kinetic energy of the geometry suggests the local turbulence kinetic energy has been influenced strongly by the alignments of the right angle triangle.

Influence of hydrophobic micelle structure on crystallization of the photosynthetic RC-LH1-PufX complex from Rhodobacter blasticus.

PubMed

Barret, Laurie-Anne; Barrot-Ivolot, Cherone; Raynal, Simon; Jungas, Colette; Polidori, Ange; Bonneté, Françoise

2013-07-25

Small angle X-ray scattering (SAXS) experiments are performed on two non-ionic surfactants, the dodecyl β-maltoside (DDβM) and the propyl(bi)cyclohexyl α-maltoside (PCCαM), a maltoside derivative containing a rigid bicyclohexyl group as hydrophobic chain, in order to compare the influence of both hydrophobic moiety structure and anomeric form on micelle form factors and intermicellar interactions relevant for membrane protein crystallization. Density and refractive index measurements were performed in order to determine volumetric and optical properties of surfactants, essential for determination of micelle molar masses by both SAXS and SEC-MALLS. SAXS form factors were analyzed by Guinier approximation and inverse Fourier transformation, to obtain the radius of gyration (RG) and the pair distribution function (P(r)) of each surfactant. Form factor model fitting was also performed to describe the shape and the assembly of both surfactant micelles. Finally, second virial coefficients were measured at different percentages of polyethylene glycol 3350, in order to correlate surfactant intermicellar interactions and RC-LH1-PufX phase diagram. It is thus found that while size, shape, and dimensions of micelles are slightly similar for both surfactants, their molar mass and aggregation number differ significantly. PCCαM are more densely packed than DDβM, which reflects (1) an increase in van der Waals contacts between PCCαM hydrophobic chains in the micelle bulk and (2) a supplementary intermicellar attraction compared to DDβM. Finally addition of PEG, which induces a depletion attraction, decreases the solubility of the RC-LH1-PufX complex in PCCαM.

Shape-Based Virtual Screening with Volumetric Aligned Molecular Shapes

PubMed Central

Koes, David Ryan; Camacho, Carlos J.

2014-01-01

Shape-based virtual screening is an established and effective method for identifying small molecules that are similar in shape and function to a reference ligand. We describe a new method of shape-based virtual screening, volumetric aligned molecular shapes (VAMS). VAMS uses efficient data structures to encode and search molecular shapes. We demonstrate that VAMS is an effective method for shape-based virtual screening and that it can be successfully used as a pre-filter to accelerate more computationally demanding search algorithms. Unique to VAMS is a novel minimum/maximum shape constraint query for precisely specifying the desired molecular shape. Shape constraint searches in VAMS are particularly efficient and millions of shapes can be searched in a fraction of a second. We compare the performance of VAMS with two other shape-based virtual screening algorithms a benchmark of 102 protein targets consisting of more than 32 million molecular shapes and find that VAMS provides a competitive trade-off between run-time performance and virtual screening performance. PMID:25049193

Effective spring stiffness for a periodic array of interacting coplanar penny-shaped cracks at an interface between two dissimilar isotropic materials

PubMed Central

Lekesiz, Huseyin; Katsube, Noriko; Rokhlin, Stanislav I.; Seghi, Robert R.

2013-01-01

An effective spring stiffness approximation is proposed for a hexagonal array of coplanar penny shaped cracks located at the interface between two dissimilar solids. The approximation is based on the factorization of the solution on the material dissimilarity factor, the crack interaction factor and the effective spring stiffness solution for non-interacting cracks in a homogeneous material. Such factorization is exact and was validated for 2D collinear cracks between two dissimilar solids. The crack interaction factor is obtained using a recently developed model for stress intensity factors for an array of coplanar penny shaped cracks in a homogeneous material; also the material dissimilarity function recently obtained for non-interacting penny shaped crack at the interface between two dissimilar materials is employed. The obtained solution is useful for an assessment by ultrasonic measurements of the interface stiffness in bonded structures for monitoring the interfacial microdamage growth due to mechanical loading and environmental factors. PMID:27175036

Effective spring stiffness for a periodic array of interacting coplanar penny-shaped cracks at an interface between two dissimilar isotropic materials.

PubMed

Lekesiz, Huseyin; Katsube, Noriko; Rokhlin, Stanislav I; Seghi, Robert R

2013-08-15

An effective spring stiffness approximation is proposed for a hexagonal array of coplanar penny shaped cracks located at the interface between two dissimilar solids. The approximation is based on the factorization of the solution on the material dissimilarity factor, the crack interaction factor and the effective spring stiffness solution for non-interacting cracks in a homogeneous material. Such factorization is exact and was validated for 2D collinear cracks between two dissimilar solids. The crack interaction factor is obtained using a recently developed model for stress intensity factors for an array of coplanar penny shaped cracks in a homogeneous material; also the material dissimilarity function recently obtained for non-interacting penny shaped crack at the interface between two dissimilar materials is employed. The obtained solution is useful for an assessment by ultrasonic measurements of the interface stiffness in bonded structures for monitoring the interfacial microdamage growth due to mechanical loading and environmental factors.

The Importance of HRA in Human Space Flight: Understanding the Risks

NASA Technical Reports Server (NTRS)

Hamlin, Teri

2010-01-01

Human performance is critical to crew safety during space missions. Humans interact with hardware and software during ground processing, normal flight, and in response to events. Human interactions with hardware and software can cause Loss of Crew and/or Vehicle (LOCV) through improper actions, or may prevent LOCV through recovery and control actions. Humans have the ability to deal with complex situations and system interactions beyond the capability of machines. Human Reliability Analysis (HRA) is a method used to qualitatively and quantitatively assess the occurrence of human failures that affect availability and reliability of complex systems. Modeling human actions with their corresponding failure probabilities in a Probabilistic Risk Assessment (PRA) provides a more complete picture of system risks and risk contributions. A high-quality HRA can provide valuable information on potential areas for improvement, including training, procedures, human interfaces design, and the need for automation. Modeling human error has always been a challenge in part because performance data is not always readily available. For spaceflight, the challenge is amplified not only because of the small number of participants and limited amount of performance data available, but also due to the lack of definition of the unique factors influencing human performance in space. These factors, called performance shaping factors in HRA terminology, are used in HRA techniques to modify basic human error probabilities in order to capture the context of an analyzed task. Many of the human error modeling techniques were developed within the context of nuclear power plants and therefore the methodologies do not address spaceflight factors such as the effects of microgravity and longer duration missions. This presentation will describe the types of human error risks which have shown up as risk drivers in the Shuttle PRA which may be applicable to commercial space flight. As with other large PRAs of complex machines, human error in the Shuttle PRA proved to be an important contributor (12 percent) to LOCV. An existing HRA technique was adapted for use in the Shuttle PRA, but additional guidance and improvements are needed to make the HRA task in space-related PRAs easier and more accurate. Therefore, this presentation will also outline plans for expanding current HRA methodology to more explicitly cover spaceflight performance shaping factors.

Shifting gears: dynamic muscle shape changes and force-velocity behavior in the medial gastrocnemius.

PubMed

Dick, Taylor J M; Wakeling, James M

2017-12-01

When muscles contract, they bulge in thickness or in width to maintain a (nearly) constant volume. These dynamic shape changes are tightly linked to the internal constraints placed on individual muscle fibers and play a key functional role in modulating the mechanical performance of skeletal muscle by increasing its range of operating velocities. Yet to date we have a limited understanding of the nature and functional implications of in vivo dynamic muscle shape change under submaximal conditions. This study determined how the in vivo changes in medial gastrocnemius (MG) fascicle velocity, pennation angle, muscle thickness, and subsequent muscle gearing varied as a function of force and velocity. To do this, we obtained recordings of MG tendon length, fascicle length, pennation angle, and thickness using B-mode ultrasound and muscle activation using surface electromyography during cycling at a range of cadences and loads. We found that that increases in contractile force were accompanied by reduced bulging in muscle thickness, reduced increases in pennation angle, and faster fascicle shortening. Although the force and velocity of a muscle contraction are inversely related due to the force-velocity effect, this study has shown how dynamic muscle shape changes are influenced by force and not influenced by velocity. NEW & NOTEWORTHY During movement, skeletal muscles contract and bulge in thickness or width. These shape changes play a key role in modulating the performance of skeletal muscle by increasing its range of operating velocities. Yet to date the underlying mechanisms associated with muscle shape change remain largely unexplored. This study identified muscle force, and not velocity, as the mechanistic driving factor to allow for muscle gearing to vary depending on the contractile conditions during human cycling. Copyright © 2017 the American Physiological Society.

Wave energy and swimming performance shape coral reef fish assemblages

PubMed Central

Fulton, C.J; Bellwood, D.R; Wainwright, P.C

2005-01-01

Physical factors often have an overriding influence on the distribution patterns of organisms, and can ultimately shape the long-term structure of communities. Although distribution patterns in sessile marine organisms have frequently been attributed to functional characteristics interacting with wave-induced water motion, similar evidence for mobile organisms is lacking. Links between fin morphology and swimming performance were examined in three diverse coral reef fish families from two major evolutionary lineages. Among-habitat variation in morphology and performance was directly compared with quantitative values of wave-induced water motion from seven coral reef habitats of different depth and wave exposure on the Great Barrier Reef. Fin morphology was strongly correlated with both field and experimental swimming speeds in all three families. The range of observed swimming speeds coincided closely with the magnitude of water velocities commonly found on coral reefs. Distribution patterns in all three families displayed highly congruent relationships between fin morphology and wave-induced water motion. Our findings indicate a general functional relationship between fin morphology and swimming performance in labriform-swimming fishes, and provide quantitative evidence that wave energy may directly influence the assemblage structure of coral reef fishes through interactions with morphology and swimming performance. PMID:15888415

Output calculation of electron therapy at extended SSD using an improved LBR method.

PubMed

Alkhatib, Hassaan A; Gebreamlak, Wondesen T; Tedeschi, David J; Mihailidis, Dimitris; Wright, Ben W; Neglia, William J; Sobash, Philip T; Fontenot, Jonas D

2015-02-01

To calculate the output factor (OPF) of any irregularly shaped electron beam at extended SSD. Circular cutouts were prepared from 2.0 cm diameter to the maximum possible size for 15 × 15 applicator cone. In addition, two irregular cutouts were prepared. For each cutout, percentage depth dose (PDD) at the standard SSD and doses at different SSD values were measured using 6, 9, 12, and 16 MeV electron beam energies on a Varian 2100C LINAC and the distance at which the central axis electron fluence becomes independent of cutout size was determined. The measurements were repeated with an ELEKTA Synergy LINAC using 14 × 14 applicator cone and electron beam energies of 6, 9, 12, and 15 MeV. The PDD measurements were performed using a scanning system and two diodes-one for the signal and the other a stationary reference outside the tank. The doses of the circular cutouts at different SSDs were measured using PTW 0.125 cm(3) Semiflex ion-chamber and EDR2 films. The electron fluence was measured using EDR2 films. For each circular cutout, the lateral buildup ratio (LBR) was calculated from the measured PDD curve using the open applicator cone as the reference field. The effective SSD (SSDeff) of each circular cutout was calculated from the measured doses at different SSD values. Using the LBR value and the radius of the circular cutout, the corresponding lateral spread parameter [σR(z)] was calculated. Taking the cutout size dependence of σR(z) into account, the PDD curves of the irregularly shaped cutouts at the standard SSD were calculated. Using the calculated PDD curve of the irregularly shaped cutout along with the LBR and SSDeff values of the circular cutouts, the output factor of the irregularly shaped cutout at extended SSD was calculated. Finally, both the calculated PDD curves and output factor values were compared with the measured values. The improved LBR method has been generalized to calculate the output factor of electron therapy at extended SSD. The percentage difference between the calculated and the measured output factors of irregularly shaped cutouts in a clinical useful SSD region was within 2%. Similar results were obtained for all available electron energies of both Varian 2100C and ELEKTA Synergy machines.

3-D Modeling of Double-Diffusive Convection During Directional Solidification of a Non-Dilute Alloy with Application to the HgCdTe Growth Under Microgravity Conditions

NASA Technical Reports Server (NTRS)

Bune, Andris V.; Gillies, Donald C.; Lehoczky, Sandor L.

1998-01-01

A numerical calculation for a non-dilute alloy solidification was performed using the FIDAP finite element code. For low growth velocities plane front solidification occurs. The location and the shape of the interface was determined using melting temperatures from the HgCdTe liquidus curve. The low thermal conductivity of the solid HgCdTe causes thermal short circuit through the ampoule walls, resulting in curved isotherms in the vicinity of the interface. Double-diffusive convection in the melt is caused by radial temperature gradients and by material density inversion with temperature. Cooling from below and the rejection at the solid-melt interface of the heavier HgTe-rich solute each tend to reduce convection. Because of these complicating factors dimensional rather then non-dimensional modeling was performed. Estimates of convection contributions for various gravity conditions was performed parametrically. For gravity levels higher then 1 0 -7 of earth's gravity it was found that the maximum convection velocity is extremely sensitive to gravity vector orientation and can be reduced at least by factor of 50% for precise orientation of the ampoule in the microgravity environment. The predicted interface shape is in agreement with one obtained experimentally by quenching. The results of 3-D modeling are compared with previous 2-D finding. A video film featuring melt convection will be presented.

Adaptive output-based command shaping for sway control of a 3D overhead crane with payload hoisting and wind disturbance

NASA Astrophysics Data System (ADS)

Abdullahi, Auwalu M.; Mohamed, Z.; Selamat, H.; Pota, Hemanshu R.; Zainal Abidin, M. S.; Ismail, F. S.; Haruna, A.

2018-01-01

Payload hoisting and wind disturbance during crane operations are among the challenging factors that affect a payload sway and thus, affect the crane's performance. This paper proposes a new online adaptive output-based command shaping (AOCS) technique for an effective payload sway reduction of an overhead crane under the influence of those effects. This technique enhances the previously developed output-based command shaping (OCS) which was effective only for a fixed system and without external disturbances. Unlike the conventional input shaping design technique which requires the system's natural frequency and damping ratio, the proposed technique is designed by using the output signal and thus, an online adaptive algorithm can be formulated. To test the effectiveness of the AOCS, experiments are carried out using a laboratory overhead crane with a payload hoisting in the presence of wind, and with different payloads. The superiority of the method is confirmed by 82% and 29% reductions in the overall sway and the maximum transient sway respectively, when compared to the OCS, and two robust input shapers namely Zero Vibration Derivative-Derivative and Extra-Insensitive shapers. Furthermore, the method demonstrates a uniform crane's performance under all conditions. It is envisaged that the proposed method can be very useful in designing an effective controller for a crane system with an unknown payload and under the influence of external disturbances.

France: Factors Shaping Foreign Policy, and Issues in U.S.-French Relations

DTIC Science & Technology

2008-05-21

view, France should seek a balance that embraces diversity yet preserves a degree of uniformity that sustains the French “identity.” He believes that...Order Code RL32464 France : Factors Shaping Foreign Policy, and Issues in U.S.- French Relations Updated May 21, 2008 Paul Gallis Specialist in... France : Factors Shaping Foreign Policy, and Issues in U.S.- French Relations 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

How does context influence performance of community health workers in low- and middle-income countries? Evidence from the literature.

PubMed

Kok, Maryse C; Kane, Sumit S; Tulloch, Olivia; Ormel, Hermen; Theobald, Sally; Dieleman, Marjolein; Taegtmeyer, Miriam; Broerse, Jacqueline E W; de Koning, Korrie A M

2015-03-07

Community health workers (CHWs) are increasingly recognized as an integral component of the health workforce needed to achieve public health goals in low- and middle-income countries (LMICs). Many factors intersect to influence CHW performance. A systematic review with a narrative analysis was conducted to identify contextual factors influencing performance of CHWs. We searched six databases for quantitative, qualitative, and mixed-methods studies that included CHWs working in promotional, preventive or curative primary health care services in LMICs. We differentiated CHW performance outcome measures at two levels: CHW level and end-user level. Ninety-four studies met the inclusion criteria and were double read to extract data relevant to the context of CHW programmes. Thematic coding was conducted and evidence on five main categories of contextual factors influencing CHW performance was synthesized. Few studies had the influence of contextual factors on CHW performance as their primary research focus. Contextual factors related to community (most prominently), economy, environment, and health system policy and practice were found to influence CHW performance. Socio-cultural factors (including gender norms and values and disease related stigma), safety and security and education and knowledge level of the target group were community factors that influenced CHW performance. Existence of a CHW policy, human resource policy legislation related to CHWs and political commitment were found to be influencing factors within the health system policy context. Health system practice factors included health service functionality, human resources provisions, level of decision-making, costs of health services, and the governance and coordination structure. All contextual factors can interact to shape CHW performance and affect the performance of CHW interventions or programmes. Research on CHW programmes often does not capture or explicitly discuss the context in which CHW interventions take place. This synthesis situates and discusses the influence of context on CHW and programme performance. Future health policy and systems research should better address the complexity of contextual influences on programmes. This insight can help policy makers and programme managers to develop CHW interventions that adequately address and respond to context to optimise performance.

The effect of time synchronization of wireless sensors on the modal analysis of structures

NASA Astrophysics Data System (ADS)

Krishnamurthy, V.; Fowler, K.; Sazonov, E.

2008-10-01

Driven by the need to reduce the installation cost and maintenance cost of structural health monitoring (SHM) systems, wireless sensor networks (WSNs) are becoming increasingly popular. Perfect time synchronization amongst the wireless sensors is a key factor enabling the use of low-cost, low-power WSNs for structural health monitoring applications based on output-only modal analysis of structures. In this paper we present a theoretical framework for analysis of the impact created by time delays in the measured system response on the reconstruction of mode shapes using the popular frequency domain decomposition (FDD) technique. This methodology directly estimates the change in mode shape values based on sensor synchronicity. We confirm the proposed theoretical model by experimental validation in modal identification experiments performed on an aluminum beam. The experimental validation was performed using a wireless intelligent sensor and actuator network (WISAN) which allows for close time synchronization between sensors (0.6-10 µs in the tested configuration) and guarantees lossless data delivery under normal conditions. The experimental results closely match theoretical predictions and show that even very small delays in output response impact the mode shapes.

Alcohol consumption and all-cause mortality.

PubMed

Duffy, J C

1995-02-01

Prospective studies of alcohol and mortality in middle-aged men almost universally find a U-shaped relationship between alcohol consumption and risk of mortality. This review demonstrates the extent to which different studies lead to different risk estimates, analyses the putative influence of abstention as a risk factor and uses available data to produce point and interval estimates of the consumption level apparently associated with minimum risk from two studies in the UK. Data from a number of studies are analysed by means of logistic-linear modelling, taking account of the possible influence of abstention as a special risk factor. Separate analysis of British data is performed. Logistic-linear modelling demonstrates large and highly significant differences between the studies considered in the relationship between alcohol consumption and all-cause mortality. The results support the identification of abstention as a special risk factor for mortality, but do not indicate that this alone explains the apparent U-shaped relationship. Separate analysis of two British studies indicates minimum risk of mortality in this population at a consumption level of about 26 (8.5 g) units of alcohol per week. The analysis supports the view that abstention may be a specific risk factor for all-cause mortality, but is not an adequate explanation of the apparent protective effect of alcohol consumption against all-cause mortality. Future analyses might better be performed on a case-by-case basis, using a change-point model to estimate the parameters of the relationship. The current misinterpretation of the sensible drinking level of 21 units per week for men in the UK as a limit is not justified, and the data suggest that alcohol consumption is a net preventive factor against premature death in this population.

Prediction of the diffuse-field transmission loss of interior natural-ventilation openings and silencers.

PubMed

Bibby, Chris; Hodgson, Murray

2017-01-01

The work reported here, part of a study on the performance and optimal design of interior natural-ventilation openings and silencers ("ventilators"), discusses the prediction of the acoustical performance of such ventilators, and the factors that affect it. A wave-based numerical approach-the finite-element method (FEM)-is applied. The development of a FEM technique for the prediction of ventilator diffuse-field transmission loss is presented. Model convergence is studied with respect to mesh, frequency-sampling and diffuse-field convergence. The modeling technique is validated by way of predictions and the comparison of them to analytical and experimental results. The transmission-loss performance of crosstalk silencers of four shapes, and the factors that affect it, are predicted and discussed. Performance increases with flow-path length for all silencer types. Adding elbows significantly increases high-frequency transmission loss, but does not increase overall silencer performance which is controlled by low-to-mid-frequency transmission loss.

Black Students and Mathematics Achievement: A Mixed-Method Analysis of In-School and Out-of-School Factors Shaping Student Success

ERIC Educational Resources Information Center

Russell, Nicole M.

2011-01-01

Achievement gap language has become associated with the observed disparities on a number of educational measures between the academic performances of Black and White students. This theoretical lens is problematic because it sends an unintended message that Black students are not worthy of study in their own right. Using a mixed-methodological…

A Comparative Analysis of the Factors Associated with Career Aspirations of Brazilian Students by Sex and Grade Level.

ERIC Educational Resources Information Center

Lupidi, Helena R.

Sex-related variations in the formation of educational and occupational aspirations of fifth and ninth grade Brazilian boys and girls were assessed via comparison of their academic performance, level of occupational and educational goals, and about the influence of family, peers, and teachers in shaping these goals. Data were collected on 1,950…

The quiescent H-mode regime for high performance edge localized mode-stable operation in future burning plasmas [The quiescent H-mode regime for high performance ELM-stable operation in future burning plasmas

DOE PAGES

Garofalo, Andrea M.; Burrell, Keith H.; Eldon, David; ...

2015-05-26

For the first time, DIII-D experiments have achieved stationary quiescent H-mode (QH-mode) operation for many energy confinement times at simultaneous ITER-relevant values of beta, confinement, and safety factor, in an ITER similar shape. QH-mode provides excellent energy confinement, even at very low plasma rotation, while operating without edge localized modes (ELMs) and with strong impurity transport via the benign edge harmonic oscillation (EHO). By tailoring the plasma shape to improve the edge stability, the QH-mode operating space has also been extended to densities exceeding 80% of the Greenwald limit, overcoming the long-standing low-density limit of QH-mode operation. In the theory,more » the density range over which the plasma encounters the kink-peeling boundary widens as the plasma cross-section shaping is increased, thus increasing the QH-mode density threshold. Here, the DIII-D results are in excellent agreement with these predictions, and nonlinear MHD analysis of reconstructed QH-mode equilibria shows unstable low n kink-peeling modes growing to a saturated level, consistent with the theoretical picture of the EHO. Furthermore, high density operation in the QH-mode regime has opened a path to a new, previously predicted region of parameter space, named “Super H-mode” because it is characterized by very high pedestals that can be more than a factor of two above the peeling-ballooning stability limit for similar ELMing H-mode discharges at the same density.« less

An application of principal component analysis to the clavicle and clavicle fixation devices.

PubMed

Daruwalla, Zubin J; Courtis, Patrick; Fitzpatrick, Clare; Fitzpatrick, David; Mullett, Hannan

2010-03-26

Principal component analysis (PCA) enables the building of statistical shape models of bones and joints. This has been used in conjunction with computer assisted surgery in the past. However, PCA of the clavicle has not been performed. Using PCA, we present a novel method that examines the major modes of size and three-dimensional shape variation in male and female clavicles and suggests a method of grouping the clavicle into size and shape categories. Twenty-one high-resolution computerized tomography scans of the clavicle were reconstructed and analyzed using a specifically developed statistical software package. After performing statistical shape analysis, PCA was applied to study the factors that account for anatomical variation. The first principal component representing size accounted for 70.5 percent of anatomical variation. The addition of a further three principal components accounted for almost 87 percent. Using statistical shape analysis, clavicles in males have a greater lateral depth and are longer, wider and thicker than in females. However, the sternal angle in females is larger than in males. PCA confirmed these differences between genders but also noted that men exhibit greater variance and classified clavicles into five morphological groups. This unique approach is the first that standardizes a clavicular orientation. It provides information that is useful to both, the biomedical engineer and clinician. Other applications include implant design with regard to modifying current or designing future clavicle fixation devices. Our findings support the need for further development of clavicle fixation devices and the questioning of whether gender-specific devices are necessary.

Understanding Galaxy Shapes Across Cosmic Time Using The IllustrisTNG Simulation

NASA Astrophysics Data System (ADS)

Genel, Shy

2017-08-01

Legacy HST observations have enabled groundbreaking measurements of galaxy structure over cosmic time, measurements that still require theoretical interpretation in the context of a comprehensive galaxy evolution model. This proposed research aims at significantly promoting our understanding of the shapes of galaxies as quantified by their principal axes ratios. The main tool we propose to use is IllustrisTNG, a suite consisting of two of the largest cosmological hydrodynamical simulations run to date, which contain resolved galaxy populations (thousands of L* galaxies) that represent a state-of-the-art match to observed galaxies. In Part I of the program, we will use the simulations to create mock images and study the dependence of projected shape measurements on various factors: shape estimator, observed band, the presence of dust, radial and surface brightness cuts, and noise. We will then perform apples-to-apples comparison with observations (including HST), and provide predictions for archival as well as future observations. Further, we will quantify the intrinsic, three-dimensional, shape distribution of galaxies as a function of various galaxy parameters: redshift, mass, color, and size. In Part II of the program, we will develop theoretical insights into the physical mechanisms driving these results. We will study how galaxy shapes relate to angular momentum and merger history, and will follow the shape evolution of individual galaxies over time, looking for correlations to the evolution of other galaxy properties, e.g. size and SFR. We will also study galaxy shape relations to dark matter halo shape, thereby providing input for high-precision cosmic shear models.

Organizational/institutional factors affecting performance in the nuclear power industry

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

Benson, J.L.

1992-01-01

The dramatic macro experiences occurring at Three Mile Island and Chernobyl as well as the cumulative micro experiences represented by sky-rocketing costs and public concerns have demonstrated how the institutionally and organizationally related aspects of the nuclear power industry have dominated and shaped the technical ones. Further, given the relatively stable or evolutionary nature of the technology as it is currently applied, these institutional and organizational factors contain the roots of most of the complications/problems associated with the industry relative to achieving any or all of its future performance objectives (technical, economic, and safety). Some technology transfer was attempted bymore » the author from the field of general systems/cybernetics, which was explicitly aimed at dealing with the organizational/institutional factors, i.e., the problems and issues were approached using principles and methodology substantially different from that typically seen from applications based on the more traditional paradigmic engineering/industrial management orientation.« less

Double resonance calibration of g factor standards: Carbon fibers as a high precision standard.

PubMed

Herb, Konstantin; Tschaggelar, Rene; Denninger, Gert; Jeschke, Gunnar

2018-04-01

The g factor of paramagnetic defects in commercial high performance carbon fibers was determined by a double resonance experiment based on the Overhauser shift due to hyperfine coupled protons. Our carbon fibers exhibit a single, narrow and perfectly Lorentzian shaped ESR line and a g factor slightly higher than g free with g=2.002644=g free ·(1+162ppm) with a relative uncertainty of 15ppm. This precisely known g factor and their inertness qualify them as a high precision g factor standard for general purposes. The double resonance experiment for calibration is applicable to other potential standards with a hyperfine interaction averaged by a process with very short correlation time. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

SEIPS 2.0: a human factors framework for studying and improving the work of healthcare professionals and patients.

PubMed

Holden, Richard J; Carayon, Pascale; Gurses, Ayse P; Hoonakker, Peter; Hundt, Ann Schoofs; Ozok, A Ant; Rivera-Rodriguez, A Joy

2013-01-01

Healthcare practitioners, patient safety leaders, educators and researchers increasingly recognise the value of human factors/ergonomics and make use of the discipline's person-centred models of sociotechnical systems. This paper first reviews one of the most widely used healthcare human factors systems models, the Systems Engineering Initiative for Patient Safety (SEIPS) model, and then introduces an extended model, 'SEIPS 2.0'. SEIPS 2.0 incorporates three novel concepts into the original model: configuration, engagement and adaptation. The concept of configuration highlights the dynamic, hierarchical and interactive properties of sociotechnical systems, making it possible to depict how health-related performance is shaped at 'a moment in time'. Engagement conveys that various individuals and teams can perform health-related activities separately and collaboratively. Engaged individuals often include patients, family caregivers and other non-professionals. Adaptation is introduced as a feedback mechanism that explains how dynamic systems evolve in planned and unplanned ways. Key implications and future directions for human factors research in healthcare are discussed.

[An experimental study of effects of active-heating-system for extravehicular spacesuit gloves on working performance].

PubMed

Ding, Li; Han, Long-zhu; Yang, Chun-xin; Yang, Feng; Yuan, Xiu-gan

2005-02-01

To observe the effects of active heating system for spacesuit gloves on extravehicular working performance. After analyzing the factors with gloves influence on the working performance, the effects of active heating system for gloves were studied experimentally with aspects to fatigue, hand strength, dexterity and tactile sensing. 1) Heating-system had not influence to grip; 2) Heating-system had 17% influence to fatigue except specific person; 3) Nut assembly and nipping pin showed that heating-system had little influence to dexterity; 4) Apperceiving shape of object and two-point distance showed heating-system had little influence to tactility. The active heating method is rational and has little influence on working performance.

Prediction of inspiratory flow shapes during sleep with a mathematic model of upper airway forces.

PubMed

Aittokallio, Tero; Gyllenberg, Mats; Saaresranta, Tarja; Polo, Olli

2003-11-01

To predict the airflow dynamics during sleep using a mathematic model that incorporates a number of static and dynamic upper airway forces, and to compare the numerical results to clinical flow data recorded from patients with sleep-disordered breathing on and off various treatment options. Upper airway performance was modeled in virtual subjects characterized by parameter settings that describe common combinations of risk factors predisposing to upper airway collapse during sleep. The treatments effect were induced by relevant changes of the initial parameter values. Computer simulations at our website (http://www.utu.fi/ml/sovmat/bio/). Risk factors considered in the simulation settings were sex, obesity, pharyngeal collapsibility, and decreased phasic activity of pharyngeal muscles. The effects of weight loss, pharyngeal surgery, nasal continuous positive airway pressure, and respiratory stimulation on the inspiratory flow characteristics were tested with the model. Numerical predictions were investigated by means of 3 measurable inspiratory airflow characteristics: initial slope, total volume, and flow shape. The model was able to reproduce the inspiratory flow shape characteristics that have previously been described in the literature. Simulation results also supported the observations that a multitude of factors underlie the pharyngeal collapse and, therefore, certain medical therapies that are effective in some conditions may prove ineffective in others. A mathematic model integrating the current knowledge of upper airway physiology is able to predict individual treatment responses. The model provides a framework for designing novel and potentially feasible treatment alternatives for sleep-disordered breathing.

Selection Shapes Transcriptional Logic and Regulatory Specialization in Genetic Networks

PubMed Central

Fogelmark, Karl; Peterson, Carsten; Troein, Carl

2016-01-01

Background Living organisms need to regulate their gene expression in response to environmental signals and internal cues. This is a computational task where genes act as logic gates that connect to form transcriptional networks, which are shaped at all scales by evolution. Large-scale mutations such as gene duplications and deletions add and remove network components, whereas smaller mutations alter the connections between them. Selection determines what mutations are accepted, but its importance for shaping the resulting networks has been debated. Methodology To investigate the effects of selection in the shaping of transcriptional networks, we derive transcriptional logic from a combinatorially powerful yet tractable model of the binding between DNA and transcription factors. By evolving the resulting networks based on their ability to function as either a simple decision system or a circadian clock, we obtain information on the regulation and logic rules encoded in functional transcriptional networks. Comparisons are made between networks evolved for different functions, as well as with structurally equivalent but non-functional (neutrally evolved) networks, and predictions are validated against the transcriptional network of E. coli. Principal Findings We find that the logic rules governing gene expression depend on the function performed by the network. Unlike the decision systems, the circadian clocks show strong cooperative binding and negative regulation, which achieves tight temporal control of gene expression. Furthermore, we find that transcription factors act preferentially as either activators or repressors, both when binding multiple sites for a single target gene and globally in the transcriptional networks. This separation into positive and negative regulators requires gene duplications, which highlights the interplay between mutation and selection in shaping the transcriptional networks. PMID:26927540

On the analysis of incoherent scatter radar data from non-thermal ionospheric plasma - Effects of measurement noise and an inexact theory

NASA Astrophysics Data System (ADS)

Suvanto, K.

1990-07-01

Statistical inversion theory is employed to estimate parameter uncertainties in incoherent scatter radar studies of non-Maxwellian ionospheric plasma. Measurement noise and the inexact nature of the plasma model are considered as potential sources of error. In most of the cases investigated here, it is not possible to determine electron density, line-of-sight ion and electron temperatures, ion composition, and two non-Maxwellian shape factors simultaneously. However, if the molecular ion velocity distribution is highly non-Maxwellian, all these quantities can sometimes be retrieved from the data. This theoretical result supports the validity of the only successful non-Maxwellian, mixed-species fit discussed in the literature. A priori information on one of the parameters, e.g., the electron density, often reduces the parameter uncertainties significantly and makes composition fits possible even if the six-parameter fit cannot be performed. However, small (less than 0.5) non-Maxwellian shape factors remain difficult to distinguish.

New scramblers for precision radial velocity: square and octagonal fibers

NASA Astrophysics Data System (ADS)

Chazelas, Bruno; Pepe, Francesco; Wildi, François; Bouchy, Francois; Perruchot, Sandrine; Avila, Gerardo

2010-07-01

One of the remaining limitation of the precise radial velocity instruments is the imperfect scrambling produced by the circular fibers. We present here experimental studies on new optical fibers aiming at an improvement of the scrambling they provide. New fibers shapes were tested: square and octagonal. Measurements have been performed of the scrambling performances of these fibers in the near field as well FRD measurements. These fibers show extremely promising performances in the near field scrambling: an improvement of a factor 5 to 10 compared to the circular fiber. They however show some strange behavior in the far field that need to be understood.

Improving satellite retrievals of NO2 in biomass burning regions

NASA Astrophysics Data System (ADS)

Bousserez, N.; Martin, R. V.; Lamsal, L. N.; Mao, J.; Cohen, R. C.; Anderson, B. E.

2010-12-01

The quality of space-based nitrogen dioxide (NO2) retrievals from solar backscatter depends on a priori knowledge of the NO2 profile shape as well as the effects of atmospheric scattering. These effects are characterized by the air mass factor (AMF) calculation. Calculation of the AMF combines a radiative transfer calculation together with a priori information about aerosols and about NO2 profiles (shape factors), which are usually taken from a chemical transport model. In this work we assess the impact of biomass burning emissions on the AMF using the LIDORT radiative transfer model and a GEOS-Chem simulation based on a daily fire emissions inventory (FLAMBE). We evaluate the GEOS-Chem aerosol optical properties and NO2 shape factors using in situ data from the ARCTAS summer 2008 (North America) and DABEX winter 2006 (western Africa) experiments. Sensitivity studies are conducted to assess the impact of biomass burning on the aerosols and the NO2 shape factors used in the AMF calculation. The mean aerosol correction over boreal fires is negligible (+3%), in contrast with a large reduction (-18%) over African savanna fires. The change in sign and magnitude over boreal forest and savanna fires appears to be driven by the shielding effects that arise from the greater biomass burning aerosol optical thickness (AOT) above the African biomass burning NO2. In agreement with previous work, the single scattering albedo (SSA) also affects the aerosol correction. We further investigated the effect of clouds on the aerosol correction. For a fixed AOT, the aerosol correction can increase from 20% to 50% when cloud fraction increases from 0 to 30%. Over both boreal and savanna fires, the greatest impact on the AMF is from the fire-induced change in the NO2 profile (shape factor correction), that decreases the AMF by 38% over the boreal fires and by 62% of the savanna fires. Combining the aerosol and shape factor corrections together results in small differences compared to the shape factor correction alone (without the aerosol correction), indicating that a shape factor-only correction is a good approximation of the total AMF correction associated with fire emissions. We use this result to define a measurement-based correction of the AMF based on the relationship between the slant column variability and the variability of the shape factor in the lower troposphere. This method may be generalized to other types of emission sources.

Indexing Volumetric Shapes with Matching and Packing

PubMed Central

Koes, David Ryan; Camacho, Carlos J.

2014-01-01

We describe a novel algorithm for bulk-loading an index with high-dimensional data and apply it to the problem of volumetric shape matching. Our matching and packing algorithm is a general approach for packing data according to a similarity metric. First an approximate k-nearest neighbor graph is constructed using vantage-point initialization, an improvement to previous work that decreases construction time while improving the quality of approximation. Then graph matching is iteratively performed to pack related items closely together. The end result is a dense index with good performance. We define a new query specification for shape matching that uses minimum and maximum shape constraints to explicitly specify the spatial requirements of the desired shape. This specification provides a natural language for performing volumetric shape matching and is readily supported by the geometry-based similarity search (GSS) tree, an indexing structure that maintains explicit representations of volumetric shape. We describe our implementation of a GSS tree for volumetric shape matching and provide a comprehensive evaluation of parameter sensitivity, performance, and scalability. Compared to previous bulk-loading algorithms, we find that matching and packing can construct a GSS-tree index in the same amount of time that is denser, flatter, and better performing, with an observed average performance improvement of 2X. PMID:26085707

Molecular mechanics of tropocollagen-hydroxyapatite biomaterials

NASA Astrophysics Data System (ADS)

Dubey, Devendra Kumar

Hard biomaterials such as bone, dentin, and nacre show remarkable mechanical performance and serve as inspiration for development of next generation of composite materials with high strength and toughness. Such materials have primarily an organic phase (e.g. tropocollagen (TC) or chitin) and a mineral phase (e.g. hydroxyapatite (HAP) or aragonite) arranged in a staggered arrangement at nanoscopic length scales. Interfacial interactions between the organic phases and the mineral phases and structural effects arising due to the staggered and hierarchical arrangements are identified to be the two most important determinants for high mechanical performance of such biomaterials. Effects of these determinants in such biomaterials are further intertwined with factors such as loading configuration, chemical environment, mineral crystal shape, and residue sequences in polymer chains. Atomistic modeling is a desired approach to investigate such sub nanoscale issues as experimental techniques for investigations at such small scale are still in nascent stage. For this purpose, explicit three dimensional (3D) molecular dynamics (MD) and ab initio MD simulations of quasi-static mechanical deformations of idealized Tropocollagen-Hydroxyapatite (TC-HAP) biomaterials with distinct interfacial arrangements and different loading configurations are performed. Focus is on developing insights into the molecular level mechanics of TC-HAP biomaterials at fundamental lengthscale with emphasis on interface phenomenon. Idealized TC-HAP atomistic models are analyzed for their mechanical strength and fracture failure behavior from the viewpoint of interfacial interactions between TC and HAP and associated molecular mechanisms. In particular, study focuses on developing an understanding of factors such as role of interfacial structural arrangement, hierarchical structure design, influence of water, effect of changes in HAP crystal shape, and mutations in TC molecule on the mechanical strength of TC-HAP biomaterials. In conjunction, a continuum level tension-shear-chain (TSC) model is also implemented to analyze fracture resistance characteristics in TC-HAP nanocomposites. Results and analyses shed light on the failure mechanisms in TC-HAP type nanocomposite systems with a chemo-mechanical understanding of the interfacial interaction between TC and HAP. Analyses show that (1) failure of TC-HAP nanocomposites at nanoscale is predominantly peak strain dependent phenomenon, (2) presence of water in most cases strengthens the TC-HAP biomaterial by acting as a bridge via hydrogen bond mediated crosslinks, (3) TC-HAP nanostructures with plate shaped HAP crystals show higher toughness and stability as compared to TC-HAP nanostructures with needle shaped HAP crystals, and (4) mutations in TC are responsible for Osteogenesis Imperfecta bone disorder in an indirect manner, wherein mutations in TC affect the shape and distribution of mineral phase during growth and nucleation period of bone. Overall study emphasizes that interfacial structural arrangement between polymer phase and mineral phase in TC-HAP and similar nanocomposite biomaterials is an important factor in determining their mechanical strength and should be carefully studied and selected for development of high performance nanocomposite biomaterials. Findings and understandings from this research have significant impact on polymer-ceramic nanocomposite mechanics, biomaterial and biomimetic materials development, and bone fragility disorders related medical science development.

The evolving DOT enterprise : today toward tomorrow.

DOT National Transportation Integrated Search

2013-04-01

Departments of transportation (DOTs) today are being shaped by a wide range of : factors some of which are directly managed and controlled within the transportation : industry while others are external factors shaping the demand for transportatio...

Universal analytical scattering form factor for shell-, core-shell, or homogeneous particles with continuously variable density profile shape.

PubMed

Foster, Tobias

2011-09-01

A novel analytical and continuous density distribution function with a widely variable shape is reported and used to derive an analytical scattering form factor that allows us to universally describe the scattering from particles with the radial density profile of homogeneous spheres, shells, or core-shell particles. Composed by the sum of two Fermi-Dirac distribution functions, the shape of the density profile can be altered continuously from step-like via Gaussian-like or parabolic to asymptotically hyperbolic by varying a single "shape parameter", d. Using this density profile, the scattering form factor can be calculated numerically. An analytical form factor can be derived using an approximate expression for the original Fermi-Dirac distribution function. This approximation is accurate for sufficiently small rescaled shape parameters, d/R (R being the particle radius), up to values of d/R ≈ 0.1, and thus captures step-like, Gaussian-like, and parabolic as well as asymptotically hyperbolic profile shapes. It is expected that this form factor is particularly useful in a model-dependent analysis of small-angle scattering data since the applied continuous and analytical function for the particle density profile can be compared directly with the density profile extracted from the data by model-free approaches like the generalized inverse Fourier transform method. © 2011 American Chemical Society

Shape memory system with integrated actuation using embedded particles

DOEpatents

Buckley, Patrick R [New York, NY; Maitland, Duncan J [Pleasant Hill, CA

2009-09-22

A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

Shape memory system with integrated actuation using embedded particles

DOEpatents

Buckley, Patrick R [New York, NY; Maitland, Duncan J [Pleasant Hill, CA

2012-05-29

A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

Shape memory system with integrated actuation using embedded particles

DOEpatents

Buckley, Patrick R.; Maitland, Duncan J.

2014-04-01

A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

Water adsorption isotherms on porous onionlike carbonaceous particles. Simulations with the grand canonical Monte Carlo method

NASA Astrophysics Data System (ADS)

Hantal, György; Picaud, Sylvain; Hoang, Paul N. M.; Voloshin, Vladimir P.; Medvedev, Nikolai N.; Jedlovszky, Pál

2010-10-01

The grand canonical Monte Carlo method is used to simulate the adsorption isotherms of water molecules on different types of model soot particles. These soot models are constructed by first removing atoms from onion-fullerene structures in order to create randomly distributed pores inside the soot, and then performing molecular dynamics simulations, based on the reactive adaptive intermolecular reactive empirical bond order (AIREBO) description of the interaction between carbon atoms, to optimize the resulting structures. The obtained results clearly show that the main driving force of water adsorption on soot is the possibility of the formation of new water-water hydrogen bonds with the already adsorbed water molecules. The shape of the calculated water adsorption isotherms at 298 K strongly depends on the possible confinement of the water molecules in pores of the carbonaceous structure. We found that there are two important factors influencing the adsorption ability of soot. The first of these factors, dominating at low pressures, is the ability of the soot of accommodating the first adsorbed water molecules at strongly hydrophilic sites. The second factor concerns the size and shape of the pores, which should be such that the hydrogen bonding network of the water molecules filling them should be optimal. This second factor determines the adsorption properties at higher pressures.

Methodology for designing psychological habitability for the space station.

PubMed

Komastubara, A

2000-09-01

Psychological habitability is a critical quality issue for the International Space Station because poor habitability degrades performance shaping factors (PSFs) and increases human errors. However, habitability often receives rather limited design attention based on someone's superficial tastes because systematic design procedures lack habitability quality. To improve design treatment of psychological habitability, this paper proposes and discusses a design methodology for designing psychological habitability for the International Space Station.

Arthroscopic modified Mason-Allen technique for large U- or L-shaped rotator cuff tears.

PubMed

Jung, Sung-Weon; Kim, Dong-Hee; Kang, Seung-Hoon; Lee, Ji-Heon

2017-07-01

While a conventional single- or double-row repair technique could be applied for repair of C-shaped tears, a different surgical strategy should be considered for repair of U- or L-shaped tears because they typically have complex patterns with anterior, posterior, or both mobile leaves. This study was performed to examine the outcomes of the modified Mason-Allen technique for footprint restoration in the treatment of large U- or L-shaped rotator cuff tears. Thirty-two patients who underwent an arthroscopic modified Mason-Allen technique for large U- or L-shaped rotator cuff tears between January 2012 and December 2013 were included in this study. Margin convergence was first performed to reduce the tear gap and tension, and then, an arthroscopic Mason-Allen technique was performed to restore the rotator cuff footprint in a side-to-end repair fashion. All patients were evaluated preoperatively and for a minimum of 2 years of follow-up with a visual analog scale (VAS) for pain, Constant score, and ultrasonography. There was significant improvement in all VAS and Constant scores compared with the preoperative values (P < 0.001). Functional results by Constant scores included 9 cases that were classified as excellent, 11 cases as good, 8 cases as fair, and 2 cases as poor. Binary logistic regression analysis revealed that heavy work, pseudoparalysis, joint space narrowing, fatty degeneration of the SST and IST, and a positive tangent sign were found to significantly correlate with functional outcomes. Multivariable logistic regression analysis revealed that only fatty degeneration of the SST was a risk factor for fair/poor clinical outcomes. Complications occurred in 5 of the 32 patients (15.6 %), and the reoperation rate due to complications was 6.3 % (2 of 32 patients). An arthroscopic modified Mason-Allen technique was sufficient to restore the footprint of the rotator cuff in our data. Overall satisfactory results were achieved in most patients, with the exception of those with severe fatty degeneration. An arthroscopic modified Mason-Allen technique could be an effective and reliable alternative for patients with large U- or L-shaped rotator cuff tears. Case Series, Therapeutic Level IV.

Subcortical regional morphology correlates with fluid and spatial intelligence.

PubMed

Burgaleta, Miguel; MacDonald, Penny A; Martínez, Kenia; Román, Francisco J; Álvarez-Linera, Juan; Ramos González, Ana; Karama, Sherif; Colom, Roberto

2014-05-01

Neuroimaging studies have revealed associations between intelligence and brain morphology. However, researchers have focused primarily on the anatomical features of the cerebral cortex, whereas subcortical structures, such as the basal ganglia (BG), have often been neglected despite extensive functional evidence on their relation with higher-order cognition. Here we performed shape analyses to understand how individual differences in BG local morphology account for variability in cognitive performance. Structural MRI was acquired in 104 young adults (45 men, 59 women, mean age = 19.83, SD = 1.64), and the outer surface of striatal structures (caudate, nucleus accumbens, and putamen), globus pallidus, and thalamus was estimated for each subject and hemisphere. Further, nine cognitive tests were used to measure fluid (Gf), crystallized (Gc), and spatial intelligence (Gv). Latent scores for these factors were computed by means of confirmatory factor analysis and regressed vertex-wise against subcortical shape (local displacements of vertex position), controlling for age, sex, and adjusted for brain size. Significant results (FDR < 5%) were found for Gf and Gv, but not Gc, for the right striatal structures and thalamus. The main results show a relative enlargement of the rostral putamen, which is functionally connected to the right dorsolateral prefrontal cortex and other intelligence-related prefrontal areas. Copyright © 2013 Wiley Periodicals, Inc.

France: Factors Shaping Foreign Policy, and Issues in U.S.-French Relations

DTIC Science & Technology

2005-01-10

Policy, and Issues in U.S.- French Relations 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK...298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 France : Factors Shaping Foreign Policy, and Issues in U.S.- French Relations Summary The factors that...shape French foreign policy have changed since the end of the Cold War. The perspectives of France and the United States have diverged in some cases

France: Factors Shaping Foreign Policy, and Issues in U.S.-French Relations

DTIC Science & Technology

2006-05-19

Policy, and Issues in U.S.- French Relations 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK...298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 France : Factors Shaping Foreign Policy, and Issues in U.S.- French Relations Summary The factors that...shape French foreign policy have changed since the end of the Cold War. The perspectives of France and the United States have diverged in some cases

What factors mediate the relationship between global self-worth and weight and shape concerns?

PubMed

Murphy, Edel; Dooley, Barbara; Menton, Aoife; Dolphin, Louise

2016-04-01

The primary aim of this study was to investigate whether the relationship between global self-worth and weight concerns and global self-worth and shape concerns was mediated by pertinent body image factors, while controlling for gender and estimated BMI. Participants were 775 adolescents (56% male) aged 12-18years (M=14.6; SD=1.50). Mediation analysis revealed a direct and a mediated effect between global self-worth and two body image models: 1) weight concerns and 2) shape concerns. The strongest mediators in both models were physical appearance, restrained eating, and depression. Partial mediation was observed for both models, indicating that body image factors which span cognitive, affective, and behavioral constructs, explain the association between global self-worth and weight and shape concerns. Implications for future research, weight and shape concern prevention and global self-worth enhancement programs are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of neutron irradiation at 430$deg;C on the fatigue properties of SA 316L steel

NASA Astrophysics Data System (ADS)

Vandermeulen, W.; Hendrix, W.; Massaut, V.; Van de Velde, J.

1988-07-01

Fatigue tests have been carried out at 430°C on hour-glass shaped specimens of the CEC reference heat of SA 316L stainless steel. The tests were performed under constant total axial strain control with a triangular fully reversed wave shape at frequencies of 0.5, 0.05 and 0.005 Hz. Specimens irradiated at 430°C to doses of 9-12 dpa and helium contents of 80 to 145 appm showed a fatigue life reduction by about a factor of two, compared to unirradiated specimens. The cyclic stress is found to be strongly increased by the irradiation. The test frequency influences the fatigue hardening slightly but it does not affect the fatigue life.

Marked Body Shape Concerns in Female Patients Suffering from Eating Disorders: Relevance of a Clinical Sub-Group.

PubMed

Gailledrat, Lucie; Rousselet, Morgane; Venisse, Jean-Luc; Lambert, Sylvain; Rocher, Bruno; Remaud, Manon; Guilleux, Alice; Sauvaget, Anne; Eyzop, Emeline; Grall-Bronnec, Marie

2016-01-01

Concerns about body shape and weight are core diagnostic criteria for eating disorders although intensity varies between patients. Few studies have focused on the clinical differences relative to the intensity of these concerns. Nonetheless, they might have a prognostic value. This study was aimed at identifying the characteristics associated with marked body shape concerns in patients with an eating disorder. Data was collected from a systematic and standardized clinical assessment of outpatients seeking treatment in our department for eating disorders. Only female patients, suffering from anorexia nervosa or bulimia nervosa, and with "no / mild" or "marked" body shape concerns according to the Body Shape Questionnaire, were included for the present study. We focused on sociodemographic characteristics, eating disorder characteristics, axis 1 disorders, types of attachment, self-esteem and dissociation. A multiple logistic regression was performed to identify factors related to "marked" body shape concerns. In our sample (123 participants, with a mean age of 24.3 years [range 16-61]), 56.9% had marked concerns with body shape. Marked body shape concerns were associated with a major depressive episode (OR = 100.3), the use of laxatives (OR = 49.8), a high score on the item "body dissatisfaction" of the Eating Disorders Inventory scale (OR = 1.7), a higher minimum body mass index (OR = 1.73), and a high score on the item "loss of control over behavior, thoughts and emotions" from the dissociation questionnaire (OR = 10.74). These results are consistent with previous studies, and highlight the importance of denial.

High performance shape memory polymer networks based on rigid nanoparticle cores

PubMed Central

Song, Jie

2010-01-01

Smart materials that can respond to external stimuli are of widespread interest in biomedical science. Thermal-responsive shape memory polymers, a class of intelligent materials that can be fixed at a temporary shape below their transition temperature (Ttrans) and thermally triggered to resume their original shapes on demand, hold great potential as minimally invasive self-fitting tissue scaffolds or implants. The intrinsic mechanism for shape memory behavior of polymers is the freezing and activation of the long-range motion of polymer chain segments below and above Ttrans, respectively. Both Ttrans and the extent of polymer chain participation in effective elastic deformation and recovery are determined by the network composition and structure, which are also defining factors for their mechanical properties, degradability, and bioactivities. Such complexity has made it extremely challenging to achieve the ideal combination of a Ttrans slightly above physiological temperature, rapid and complete recovery, and suitable mechanical and biological properties for clinical applications. Here we report a shape memory polymer network constructed from a polyhedral oligomeric silsesquioxane nanoparticle core functionalized with eight polyester arms. The cross-linked networks comprising this macromer possessed a gigapascal-storage modulus at body temperature and a Ttrans between 42 and 48 °C. The materials could stably hold their temporary shapes for > 1 year at room temperature and achieve full shape recovery ≤ 51 °C in a matter of seconds. Their versatile structures allowed for tunable biodegradability and biofunctionalizability. These materials have tremendous promise for tissue engineering applications. PMID:20375285

Effects of source shape on the numerical aperture factor with a geometrical-optics model.

PubMed

Wan, Der-Shen; Schmit, Joanna; Novak, Erik

2004-04-01

We study the effects of an extended light source on the calibration of an interference microscope, also referred to as an optical profiler. Theoretical and experimental numerical aperture (NA) factors for circular and linear light sources along with collimated laser illumination demonstrate that the shape of the light source or effective aperture cone is critical for a correct NA factor calculation. In practice, more-accurate results for the NA factor are obtained when a linear approximation to the filament light source shape is used in a geometric model. We show that previously measured and derived NA factors show some discrepancies because a circular rather than linear approximation to the filament source was used in the modeling.

Optimal transport and the placenta

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

Morgan, Simon; Xia, Qinglan; Salafia, Carolym

2010-01-01

The goal of this paper is to investigate the expected effects of (i) placental size, (ii) placental shape and (iii) the position of insertion of the umbilical cord on the work done by the foetus heart in pumping blood across the placenta. We use optimal transport theory and modeling to quantify the expected effects of these factors . Total transport cost and the shape factor contribution to cost are given by the optimal transport model. Total placental transport cost is highly correlated with birth weight, placenta weight, FPR and the metabolic scaling factor beta. The shape factor is also highlymore » correlated with birth weight, and after adjustment for placental weight, is highly correlated with the metabolic scaling factor beta.« less

Improving the Hydrodynamic Performance of Diffuser Vanes via Shape Optimization

NASA Technical Reports Server (NTRS)

Goel, Tushar; Dorney, Daniel J.; Haftka, Raphael T.; Shyy, Wei

2007-01-01

The performance of a diffuser in a pump stage depends on its configuration and placement within the stage. The influence of vane shape on the hydrodynamic performance of a diffuser has been studied. The goal of this effort has been to improve the performance of a pump stage by optimizing the shape of the diffuser vanes. The shape of the vanes was defined using Bezier curves and circular arcs. Surrogate model based tools were used to identify regions of the vane that have a strong influence on its performance. Optimization of the vane shape, in the absence of manufacturing, and stress constraints, led to a nearly nine percent reduction in the total pressure losses compared to the baseline design by reducing the extent of the base separation.

Serum uric acid level as a risk factor for acute kidney injury in hospitalized patients: a retrospective database analysis using the integrated medical information system at Kochi Medical School hospital.

PubMed

Otomo, Kazunori; Horino, Taro; Miki, Takeo; Kataoka, Hiromi; Hatakeyama, Yutaka; Matsumoto, Tatsuki; Hamada-Ode, Kazu; Shimamura, Yoshiko; Ogata, Koji; Inoue, Kosuke; Taniguchi, Yoshinori; Terada, Yoshio; Okuhara, Yoshiyasu

2016-04-01

Recent studies have shown that both low and high levels of serum uric acid (SUA) before cardiovascular surgery are independent risk factors for postoperative acute kidney injury (AKI). However, these studies were limited by their small sample sizes. Here, we investigated the association between SUA levels and AKI by performing a retrospective database analysis of almost 30 years of data from 81,770 hospitalized patients. Hospitalized patients aged ≥18 years were retrospectively enrolled. AKI was diagnosed according to the Kidney Disease: Improving Global Outcomes 2012 Clinical Practice Guideline (KDIGO) criteria. Multivariate logistic regression analyses were performed to investigate the independent association between SUA levels and the incidence of AKI. SUA levels were treated as categorical variables because the relationship between SUA and the incidence of AKI has been suggested to be J-shaped or U-shaped. In addition to stratified SUA levels, we considered kidney function and related comorbidities, medications, and procedures performed prior to AKI onset as possible confounding risk factors. The final study cohort included 59,219 adult patients. Adjusted odds ratios of AKI incidence were higher in both the high- and low-SUA strata. Odds ratios tended to become larger in the higher range of SUA levels in women than in men. Additionally, this study showed that AKI risk was elevated in patients with SUA levels ≤7 mg/dL. An SUA level >7 mg/dL is considered the point of initiation of uric acid crystallization. SUA level could be an independent risk factor for AKI development in hospitalized patients. Additionally, our results might suggest that intervention to lower SUA levels is necessary, even in cases of moderate elevation that does not warrant hyperuricemia treatment. Results also showed that SUA levels that require attention are lower for women than for men.

Four factors for the initiation of substance use by young adulthood: A 10-year follow-up twin and sibling study of marital conflict, monitoring, siblings, and peers

PubMed Central

NEIDERHISER, JENAE M.; MARCEAU, KRISTINE; REISS, DAVID

2014-01-01

This study examined genetic and environmental influences on associations among marital conflict about the child, parental monitoring, sibling relationship negativity, and peer delinquency during adolescence and initiation of illegal drug use by young adulthood. The sample comprised data collected longitudinally from same-sex sibling pairs and parents when the siblings were 10–18 years old (M = 14.5 and 12.9 years for Child 1 and Child 2, respectively) and 20–35 years old (M = 26.8 and 25.5 years for Child 1 and Child 2, respectively). Findings indicate four factors that explain the initiation of illegal drug use: two shaped by genetic influences and two shaped by environments shared by siblings. The two genetically shaped factors probably have distinct mechanisms: one a child-initiated coercive process in the family and the other parent and peer processes shaped by the child’s disclosure. The environmentally influenced factors seem distinctively shaped by poor parental monitoring of both sibs and the effects of siblings on each other’s deviancy. PMID:23398758

Four factors for the initiation of substance use by young adulthood: a 10-year follow-up twin and sibling study of marital conflict, monitoring, siblings, and peers.

PubMed

Neiderhiser, Jenae M; Marceau, Kristine; Reiss, David

2013-02-01

This study examined genetic and environmental influences on associations among marital conflict about the child, parental monitoring, sibling relationship negativity, and peer delinquency during adolescence and initiation of illegal drug use by young adulthood. The sample comprised data collected longitudinally from same-sex sibling pairs and parents when the siblings were 10-18 years old (M = 14.5 and 12.9 years for Child 1 and Child 2, respectively) and 20-35 years old (M = 26.8 and 25.5 years for Child 1 and Child 2, respectively). Findings indicate four factors that explain the initiation of illegal drug use: two shaped by genetic influences and two shaped by environments shared by siblings. The two genetically shaped factors probably have distinct mechanisms: one a child-initiated coercive process in the family and the other parent and peer processes shaped by the child's disclosure. The environmentally influenced factors seem distinctively shaped by poor parental monitoring of both sibs and the effects of siblings on each other's deviancy.

Shape and size variation on the wing of Drosophila mediopunctata: influence of chromosome inversions and genotype-environment interaction.

PubMed

Hatadani, Luciane Mendes; Klaczko, Louis Bernard

2008-07-01

The second chromosome of Drosophila mediopunctata is highly polymorphic for inversions. Previous work reported a significant interaction between these inversions and collecting date on wing size, suggesting the presence of genotype-environment interaction. We performed experiments in the laboratory to test for the joint effects of temperature and chromosome inversions on size and shape of the wing in D. mediopunctata. Size was measured as the centroid size, and shape was analyzed using the generalized least squares Procrustes superimposition followed by discriminant analysis and canonical variates analysis of partial warps and uniform components scores. Our findings show that wing size and shape are influenced by temperature, sex, and karyotype. We also found evidence suggestive of an interaction between the effects of karyotype and temperature on wing shape, indicating the existence of genotype-environment interaction for this trait in D. mediopunctata. In addition, the association between wing size and chromosome inversions is in agreement with previous results indicating that these inversions might be accumulating alleles adapted to different temperatures. However, no significant interaction between temperature and karyotype for size was found--in spite of the significant presence of temperature-genotype (cross) interaction. We suggest that other ecological factors--such as larval crowding--or seasonal variation of genetic content within inversions may explain the previous results.

Influence of in-hole roughness and high freestream turbulence on film cooling from a shaped hole

NASA Astrophysics Data System (ADS)

Schroeder, Robert P.

Gas turbines are heavily used for electricity generation and aircraft propulsion with a strong desire in both uses to maximize thermal efficiency while maintaining reasonable power output. As a consequence, gas turbines run at high turbine inlet temperatures that require sophisticated cooling technologies to ensure survival of turbine components. One such technology is film cooling with shaped holes, where air is withdrawn from latter stages of the compressor, is bypassed around the combustor, and is eventually ejected out holes in turbine component surfaces. Air ejected from these shaped holes helps maintain components at temperatures lower than flow from the combustor. Many studies have investigated different factors that influence shaped hole performance. However, no studies in open literature have investigated how cooling performance is affected by roughness along interior walls of the shaped hole. The effect of in-hole roughness on shaped hole film cooling was the focus of this research. Investigation of in-hole roughness effects first required the determination of behavior for a shaped hole with smooth walls. A public shaped hole, now used by other investigators as well, was designed with a diffused outlet having 7º expansion angles and an area ratio of 2.5. At low freestream turbulence intensity of 0.5%, film cooling adiabatic effectiveness for this smooth hole was found to peak at a blowing ratio of 1.5. Measurements of flowfields and thermal fields revealed causes of this behavior. Blowing ratio increases above 1.5 caused the jet from the smooth hole to penetrate higher into the surrounding mainstream, exhibit a stronger counter-rotating vortex pair, and have narrower contact with the wall than at lower blowing ratios. Experiments performed at high freestream turbulence intensity of 13% revealed dynamics of how freestream turbulence both diluted and laterally spread coolant. At the high blowing ratio of 3 the dilution and spreading were competing effects, such that elevated freestream turbulence did not cause a decrease in area-averaged effectiveness. At the blowing ratio of 1.5, high freestream turbulence caused area-averaged effectiveness to decrease 17% relative to the low freestream turbulence case. Film cooling performance was measured for the shaped hole geometry with several different configurations of in-hole roughness. At low freestream turbulence intensity, in hole roughness caused decreases in area-averaged adiabatic effectiveness up to 61% relative to the smooth hole performance. These percent decreases in adiabatic effectiveness were more severe with increasing roughness levels and with increasing blowing ratios. Flowfield and thermal field measurements for the configuration with largest roughness size showed that the decrease in adiabatic effectiveness for rough holes as compared to smooth holes was due to thicker boundary layers along the interior walls of the cooling holes. The thicker boundary layers resulted in faster jet core flow, which in turn caused increased penetration of coolant into the mainstream and increased turbulence intensity inside the jet, with both leading to reduced adiabatic effectiveness. Detrimental effects of in-hole roughness persisted at the high freestream turbulence conditions as well.

Fatigue Magnification Factors of Arc-Soft-Toe Bracket Joints

NASA Astrophysics Data System (ADS)

Fu, Qiang; Li, Huajun; Wang, Hongqing; Wang, Shuqing; Li, Dejiang; Li, Qun; Fang, Hui

2018-06-01

Arc-soft-toe bracket (ASTB), as a joint structure in the marine structure, is the hot spot with significant stress concentration, therefore, fatigue behavior of ASTBs is an important point of concern in their design. Since macroscopic geometric factors obviously influence the stress flaws in joints, the shapes and sizes of ASTBs should represent the stress distribution around cracks in the hot spots. In this paper, we introduce a geometric magnification factor for reflecting the macroscopic geometric effects of ASTB crack features and construct a 3D finite element model to simulate the distribution of stress intensity factor (SIF) at the crack endings. Sensitivity analyses with respect to the geometric ratio H t / L b , R/ L b , L t / L b are performed, and the relations between the geometric factor and these parameters are presented. A set of parametric equations with respect to the geometric magnification factor is obtained using a curve fitting technique. A nonlinear relationship exists between the SIF and the ratio of ASTB arm to toe length. When the ratio of ASTB arm to toe length reaches a marginal value, the SIF of crack at the ASTB toe is not influenced by ASTB geometric parameters. In addition, the arc shape of the ASTB slope edge can transform the stress flowing path, which significantly affects the SIF at the ASTB toe. A proper method to reduce stress concentration is setting a slope edge arc size equal to the ASTB arm length.

Parametric geometric model and shape optimization of an underwater glider with blended-wing-body

NASA Astrophysics Data System (ADS)

Sun, Chunya; Song, Baowei; Wang, Peng

2015-11-01

Underwater glider, as a new kind of autonomous underwater vehicles, has many merits such as long-range, extended-duration and low costs. The shape of underwater glider is an important factor in determining the hydrodynamic efficiency. In this paper, a high lift to drag ratio configuration, the Blended-Wing-Body (BWB), is used to design a small civilian under water glider. In the parametric geometric model of the BWB underwater glider, the planform is defined with Bezier curve and linear line, and the section is defined with symmetrical airfoil NACA 0012. Computational investigations are carried out to study the hydrodynamic performance of the glider using the commercial Computational Fluid Dynamics (CFD) code Fluent. The Kriging-based genetic algorithm, called Efficient Global Optimization (EGO), is applied to hydrodynamic design optimization. The result demonstrates that the BWB underwater glider has excellent hydrodynamic performance, and the lift to drag ratio of initial design is increased by 7% in the EGO process.

Clinical Correlates of Infarct Shape and Volume in Lacunar Strokes The SPS3 Trial

PubMed Central

Asdaghi, Negar; Pearce, Leasly A.; Nakajima, Makoto; Field, Thalia S; Bazan, Carlos; Cermeno, Franco; McClure, Leslie A.; Anderson, David C.; Hart, Robert G.; Benavente, Oscar R.

2014-01-01

Background and Purpose Infarct size and location are thought to correlate with different mechanisms of lacunar infarcts. We examined the relationship between the size and shape of lacunar infarcts and vascular risk factors and outcomes. Methods We studied 1679 participants in the Secondary Prevention of Small Subcortical Stroke trial with a lacunar infarct visualized on DWI. Infarct volume was measured planimetrically, and shape was classified based on visual analysis after 3D reconstruction of axial MRI slices. Results Infarct shape was ovoid/spheroid in 63%, slab 12%, stick 7%, and multi- component 17%. Median infarct volume was smallest in ovoid/spheroid relative to other shapes: 0.46, 0.65, 0.54, and 0.90 ml respectively, p< 0.001. Distributions of vascular risk factors were similar across the four groups except that patients in the ovoid/spheroid and stick groups were more often diabetic and those with multi-component had significantly higher blood pressure at study entry. Intracranial stenosis did not differ among groups (p=0.2). Infarct volume was not associated with vascular risk factors. Increased volume was associated with worse functional status at baseline and 3 months. Overall, 162 recurrent strokes occurred over an average of 3.4 years of follow-up with no difference in recurrent ischemic stroke rate by shape or volume. Conclusion In patients with recent lacunar stroke, vascular risk factor profile was similar amongst the different infarct shapes and sizes. Infarct size correlated with worse short- term functional outcome. Neither shape nor volume was predictive of stroke recurrence. PMID:25190442

Cognitive Reserve–Mediated Modulation of Positron Emission Tomographic Activations During Memory Tasks in Alzheimer Disease

PubMed Central

Scarmeas, Nikolaos; Zarahn, Eric; Anderson, Karen E.; Honig, Lawrence S.; Park, Aileen; Hilton, John; Flynn, Joseph; Sackeim, Harold A.; Stern, Yaakov

2011-01-01

Background Cognitive reserve (CR) is the ability of an individual to cope with advancing brain pathological abnormalities so that he or she remains free of symptoms. Epidemiological data and evidence from positron emission tomography suggest that it may be mediated through education or IQ. Objective To investigate CR-mediated differential brain activation in Alzheimer disease (AD) subjects compared with healthy elderly persons. Participants Using radioactive water positron emission tomography, we scanned 12 AD patients and 17 healthy elderly persons while performing a serial recognition memory task for nonverbalizable shapes under 2 conditions: low demand, in which one shape was presented in each study trial, and titrated demand, in which the study list length was adjusted so that each subject recognized shapes at approximately 75% accuracy. Positron emission tomographic scan acquisition included the encoding and recognition phases. A CR factor score that summarized years of education, National Adult Reading Test estimated IQ, and Wechsler Adult Intelligence Scale–Revised vocabulary subtest score (explaining 71% of the total variance) was used as an index of CR. Voxel-wise, multiple regression analyses were performed with the “activation” difference (titrated demand–low demand) as the dependent variables and the CR factor score as the independent one. Brain regions where regression slopes differed between the 2 groups were identified. Results The slopes were significantly more positive for the AD patients in the left precentral gyrus and in the left hippocampus and significantly more negative in the right fusiform, right middle occipital, left superior occipital, and left middle temporal gyri. Conclusion Brain regions where systematic relationships (slopes) between subjects’ education-IQ and brain activation differ as a function of disease status may mediate the differential ability to cope with (ie, delay or modify) clinical manifestations of AD. PMID:14732623

Psychometric evaluation of a unified Portuguese-language version of the Body Shape Questionnaire in female university students.

PubMed

Silva, Wanderson Roberto; Costa, David; Pimenta, Filipa; Maroco, João; Campos, Juliana Alvares Duarte Bonini

2016-07-21

The objectives of this study were to develop a unified Portuguese-language version, for use in Brazil and Portugal, of the Body Shape Questionnaire (BSQ) and to estimate its validity, reliability, and internal consistency in Brazilian and Portuguese female university students. Confirmatory factor analysis was performed using both original (34-item) and shortened (8-item) versions. The model's fit was assessed with χ²/df, CFI, NFI, and RMSEA. Concurrent and convergent validity were assessed. Reliability was estimated through internal consistency and composite reliability (α). Transnational invariance of the BSQ was tested using multi-group analysis. The original 32-item model was refined to present a better fit and adequate validity and reliability. The shortened model was stable in both independent samples and in transnational samples (Brazil and Portugal). The use of this unified version is recommended for the assessment of body shape concerns in both Brazilian and Portuguese college students.

Dependence of recycling and edge profiles on lithium evaporation in high triangularity, high performance NSTX H-mode discharges.

DOE PAGES

Maingi, R.; Osborne, T. H.; Bell, M. G.; ...

2014-11-04

In this paper, the effects of a pre-discharge lithium evaporation variation on highly shaped discharges in the National Spherical Torus Experiment (NSTX) are documented. Lithium wall conditioning (‘dose’) was routinely applied onto graphite plasma facing components between discharges in NSTX, partly to reduce recycling. Reduced D α emission from the lower and upper divertor and center stack was observed, as well as reduced midplane neutral pressure; the magnitude of reduction increased with the pre-discharge lithium dose. Improved energy confinement, both raw τ E and H-factor normalized to scalings, with increasing lithium dose was also observed. At the highest doses, wemore » also observed elimination of edge-localized modes. The midplane edge plasma profiles were dramatically altered, comparable to lithium dose scans at lower shaping, where the strike point was farther from the lithium deposition centroid. As a result, this indicates that the benefits of lithium conditioning should apply to the highly shaped plasmas planned in NSTX-U.« less

Using Strassen's algorithm to accelerate the solution of linear systems

NASA Technical Reports Server (NTRS)

Bailey, David H.; Lee, King; Simon, Horst D.

1990-01-01

Strassen's algorithm for fast matrix-matrix multiplication has been implemented for matrices of arbitrary shapes on the CRAY-2 and CRAY Y-MP supercomputers. Several techniques have been used to reduce the scratch space requirement for this algorithm while simultaneously preserving a high level of performance. When the resulting Strassen-based matrix multiply routine is combined with some routines from the new LAPACK library, LU decomposition can be performed with rates significantly higher than those achieved by conventional means. We succeeded in factoring a 2048 x 2048 matrix on the CRAY Y-MP at a rate equivalent to 325 MFLOPS.

Morphology evolution of single-crystalline hematite nanocrystals: magnetically recoverable nanocatalysts for enhanced facet-driven photoredox activity

NASA Astrophysics Data System (ADS)

Patra, Astam K.; Kundu, Sudipta K.; Bhaumik, Asim; Kim, Dukjoon

2015-12-01

We have developed a new green chemical approach for the shape-controlled synthesis of single-crystalline hematite nanocrystals in aqueous medium. FESEM, HRTEM and SAED techniques were used to determine the morphology and crystallographic orientations of each nanocrystal and its exposed facets. PXRD and HRTEM techniques revealed that the nanocrystals are single crystalline in nature; twins and stacking faults were not detected in these nanocrystals. The structural, vibrational, and electronic spectra of these nanocrystals were highly dependent on their shape. Different shaped hematite nanocrystals with distinct crystallographic planes have been synthesized under similar reaction conditions, which can be desired as a model for the purpose of properties comparison with the nanocrystals prepared under different reaction conditions. Here we investigated the photocatalytic performance of these different shaped-nanocrystals for methyl orange degradation in the presence of white light (λ > 420 nm). In this study, we found that the density of surface Fe3+ ions in particular facets was the key factor for the photocatalytic activity and was higher on the bitruncated-dodecahedron shape nanocrystals by coexposed {104}, {100} and {001} facets, attributing to higher catalytic activity. The catalytic activity of different exposed facet nanocrystals were as follows: {104} + {100} + {001} (bitruncated-dodecahedron) > {101} + {001} (bitruncated-octahedron) > {001} + {110} (nanorods) > {012} (nanocuboid) which provided the direct evidence of exposed facet-driven photocatalytic activity. The nanocrystals were easily recoverable using an external magnet and reused at least six times without significant loss of its catalytic activity.We have developed a new green chemical approach for the shape-controlled synthesis of single-crystalline hematite nanocrystals in aqueous medium. FESEM, HRTEM and SAED techniques were used to determine the morphology and crystallographic orientations of each nanocrystal and its exposed facets. PXRD and HRTEM techniques revealed that the nanocrystals are single crystalline in nature; twins and stacking faults were not detected in these nanocrystals. The structural, vibrational, and electronic spectra of these nanocrystals were highly dependent on their shape. Different shaped hematite nanocrystals with distinct crystallographic planes have been synthesized under similar reaction conditions, which can be desired as a model for the purpose of properties comparison with the nanocrystals prepared under different reaction conditions. Here we investigated the photocatalytic performance of these different shaped-nanocrystals for methyl orange degradation in the presence of white light (λ > 420 nm). In this study, we found that the density of surface Fe3+ ions in particular facets was the key factor for the photocatalytic activity and was higher on the bitruncated-dodecahedron shape nanocrystals by coexposed {104}, {100} and {001} facets, attributing to higher catalytic activity. The catalytic activity of different exposed facet nanocrystals were as follows: {104} + {100} + {001} (bitruncated-dodecahedron) > {101} + {001} (bitruncated-octahedron) > {001} + {110} (nanorods) > {012} (nanocuboid) which provided the direct evidence of exposed facet-driven photocatalytic activity. The nanocrystals were easily recoverable using an external magnet and reused at least six times without significant loss of its catalytic activity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06509g

Jet Formation and Penetration Study of Double-Layer Shaped Charge

NASA Astrophysics Data System (ADS)

Wang, Zhe; Jiang, Jian-Wei; Wang, Shu-You; Liu, Han

2018-04-01

A theoretical analysis on detonation wave propagation in a double-layer shaped charge (DLSC) is performed. Numerical simulations using the AUTODYN software are carried out to compare the distinctions between jet formations in DLSC and ordinary shaped charge (OSC), in particular, the OSC made using a higher detonation velocity explosive, which is treated as the outer layer charge in the DLSC. The results show that the improved detonation velocity ratio and radial charge percentage of outer-to-inner layer charge are conducive to the formation of a convergent detonation wave, which contributes to enhancement of jet tip velocity in DLSC. The thickness and mass percentages of liner flowing into jet in DLSC closely follow the exponential distribution along the radial direction, but the percentages in DLSC and the mass of effective jet, which have significant influence on the penetration depth, are lower than those in OSC with the outer layer charge. This implies that the total charge energy is the major factor controlling the effective jet formation, which is confirmed by the verification tests using flash X-ray system and following penetration tests. The numerical simulation and test results compare well, while penetration test results indicate that the performance of DLSC is not better than that of OSC with the outer layer charge, due to the differences in jet formation.

Correlation Between Geometric Similarity of Ice Shapes and the Resulting Aerodynamic Performance Degradation: A Preliminary Investigation Using WIND

NASA Technical Reports Server (NTRS)

Wright, William B.; Chung, James

1999-01-01

Aerodynamic performance calculations were performed using WIND on ten experimental ice shapes and the corresponding ten ice shapes predicted by LEWICE 2.0. The resulting data for lift coefficient and drag coefficient are presented. The difference in aerodynamic results between the experimental ice shapes and the LEWICE ice shapes were compared to the quantitative difference in ice shape geometry presented in an earlier report. Correlations were generated to determine the geometric features which have the most effect on performance degradation. Results show that maximum lift and stall angle can be correlated to the upper horn angle and the leading edge minimum thickness. Drag coefficient can be correlated to the upper horn angle and the frequency-weighted average of the Fourier coefficients. Pitching moment correlated with the upper horn angle and to a much lesser extent to the upper and lower horn thicknesses.

Laser shape setting of superelastic nitinol wires: Functional properties and microstructure

NASA Astrophysics Data System (ADS)

Tuissi, Ausonio; Coduri, Mauro; Biffi, Carlo Alberto

Shape setting is one of the most important steps in the production route of Nitinol Shape Memory Alloys (SMAs), as it can fix the functional properties, such as the shape memory effect and the superelasticity (SE). The conventional method for making the shape setting is performed at 400-500∘C in furnaces. In this work, a laser beam was adopted for performing straight shape setting on commercially available austenitic Nitinol thin wires. The laser beam, at different power levels, was moved along the wire length for inducing the functional performances. Calorimetric, pseudo-elastic and microstructural features of the laser annealed wires were studied through differential scanning calorimetry, tensile testing and high energy X-ray diffraction, respectively. It can be stated that the laser technology can induce SE in thin Nitinol wires: the wire performances can be modulated in function of the laser power and improved functional properties can be obtained.

An Effective 3D Shape Descriptor for Object Recognition with RGB-D Sensors

PubMed Central

Liu, Zhong; Zhao, Changchen; Wu, Xingming; Chen, Weihai

2017-01-01

RGB-D sensors have been widely used in various areas of computer vision and graphics. A good descriptor will effectively improve the performance of operation. This article further analyzes the recognition performance of shape features extracted from multi-modality source data using RGB-D sensors. A hybrid shape descriptor is proposed as a representation of objects for recognition. We first extracted five 2D shape features from contour-based images and five 3D shape features over point cloud data to capture the global and local shape characteristics of an object. The recognition performance was tested for category recognition and instance recognition. Experimental results show that the proposed shape descriptor outperforms several common global-to-global shape descriptors and is comparable to some partial-to-global shape descriptors that achieved the best accuracies in category and instance recognition. Contribution of partial features and computational complexity were also analyzed. The results indicate that the proposed shape features are strong cues for object recognition and can be combined with other features to boost accuracy. PMID:28245553

Impact of Snow Grain Shape and Internal Mixing with Black Carbon Aerosol on Snow Optical Properties for use in Climate Models

NASA Astrophysics Data System (ADS)

He, C.; Liou, K. N.; Takano, Y.; Yang, P.; Li, Q.; Chen, F.

2017-12-01

A set of parameterizations is developed for spectral single-scattering properties of clean and black carbon (BC)-contaminated snow based on geometric-optic surface-wave (GOS) computations, which explicitly resolves BC-snow internal mixing and various snow grain shapes. GOS calculations show that, compared with nonspherical grains, volume-equivalent snow spheres show up to 20% larger asymmetry factors and hence stronger forward scattering, particularly at wavelengths <1 mm. In contrast, snow grain sizes have a rather small impact on the asymmetry factor at wavelengths <1 mm, whereas size effects are important at longer wavelengths. The snow asymmetry factor is parameterized as a function of effective size, aspect ratio, and shape factor, and shows excellent agreement with GOS calculations. According to GOS calculations, the single-scattering coalbedo of pure snow is predominantly affected by grain sizes, rather than grain shapes, with higher values for larger grains. The snow single-scattering coalbedo is parameterized in terms of the effective size that combines shape and size effects, with an accuracy of >99%. Based on GOS calculations, BC-snow internal mixing enhances the snow single-scattering coalbedo at wavelengths <1 mm, but it does not alter the snow asymmetry factor. The BC-induced enhancement ratio of snow single-scattering coalbedo, independent of snow grain size and shape, is parameterized as a function of BC concentration with an accuracy of >99%. Overall, in addition to snow grain size, both BC-snow internal mixing and snow grain shape play critical roles in quantifying BC effects on snow optical properties. The present parameterizations can be conveniently applied to snow, land surface, and climate models including snowpack radiative transfer processes.

Working Memory Units are All in Your Head: Factors that Influence Whether Features or Objects Are the Favored Units

PubMed Central

Vergauwe, Evie; Cowan, Nelson

2015-01-01

We compared two contrasting hypotheses of how multi-featured objects are stored in visual working memory (vWM): as integrated objects or as independent features. A new procedure was devised to examine vWM representations of several concurrently-held objects and their features and our main measure was reaction time (RT), allowing an examination of the real-time search through features and/or objects in an array in vWM. Response speeds to probes with color, shape or both were studied as a function of the number of memorized colored shapes. Four testing groups were created by varying the instructions and the way in which probes with both color and shape were presented. The instructions explicitly either encouraged or discouraged the use of binding information and the task-relevance of binding information was further suggested by presenting probes with both color and shapes as either integrated objects or independent features. Our results show that the unit used for retrieval from vWM depends on the testing situation. Search was fully object-based only when all factors support that basis of search, in which case retrieving two features took no longer than retrieving a single feature. Otherwise, retrieving two features took longer than retrieving a single feature. Additional analyses of change detection latency suggested that, even though different testing situations can result in a stronger emphasis on either the feature dimension or the object dimension, neither one disappears from the representation and both concurrently affect change detection performance. PMID:25705873

Working memory units are all in your head: Factors that influence whether features or objects are the favored units.

PubMed

Vergauwe, Evie; Cowan, Nelson

2015-09-01

We compared two contrasting hypotheses of how multifeatured objects are stored in visual working memory (vWM); as integrated objects or as independent features. A new procedure was devised to examine vWM representations of several concurrently held objects and their features and our main measure was reaction time (RT), allowing an examination of the real-time search through features and/or objects in an array in vWM. Response speeds to probes with color, shape, or both were studied as a function of the number of memorized colored shapes. Four testing groups were created by varying the instructions and the way in which probes with both color and shape were presented. The instructions explicitly either encouraged or discouraged the use of binding information and the task-relevance of binding information was further suggested by presenting probes with both color and shapes as either integrated objects or independent features. Our results show that the unit used for retrieval from vWM depends on the testing situation. Search was fully object-based only when all factors support that basis of search, in which case retrieving 2 features took no longer than retrieving a single feature. Otherwise, retrieving 2 features took longer than retrieving a single feature. Additional analyses of change detection latency suggested that, even though different testing situations can result in a stronger emphasis on either the feature dimension or the object dimension, neither one disappears from the representation and both concurrently affect change detection performance. (c) 2015 APA, all rights reserved).

DSN 100-meter X and S band microwave antenna design and performance

NASA Technical Reports Server (NTRS)

Williams, W. F.

1978-01-01

The RF performance is studied for large reflector antenna systems (100 meters) when using the high efficiency dual shaped reflector approach. An altered phase was considered so that the scattered field from a shaped surface could be used in the JPL efficiency program. A new dual band (X-S) microwave feed horn was used in the shaping calculations. A great many shaping calculations were made for various horn sizes and locations and final RF efficiencies are reported. A conclusion is reached that when using the new dual band horn, shaping should probably be performed using the pattern of the lower frequency

'Too-much-of-a-good-thing'? The role of advanced eco-learning and contingency factors on the relationship between corporate environmental and financial performance.

PubMed

Latan, Hengky; Chiappetta Jabbour, Charbel Jose; Lopes de Sousa Jabbour, Ana Beatriz; Renwick, Douglas William Scott; Wamba, Samuel Fosso; Shahbaz, Muhammad

2018-08-15

Inspired by the natural-resource-based view (NRBV) theory, we attempt to shed light on a controversy which has been persistent over the last decade, concerning the relationship between corporate environmental performance (CEP) and corporate financial performance (CFP). Using the 'too-much-of-a-good-thing' (TMGT) concept, which suggests that "too much can be worse than too little," we link mixed results and consider the roles of advanced eco-learning and contingency factors in influencing the CEP-CFP relationship. Based on a sample composed of ISO 14001 certified companies in Indonesia, and analyzing the data using consistent Partial Least Squares (PLSc), we found that: the CEP-CFP relationship follows an inverted U-shape; advanced eco-learning is a significant predictor of the CEP-CFP relationship, meaning that organizations able to develop higher eco-learning capability will be better able to identify the ideal boundaries of investment in environmental performance without reducing their financial performance; and that contingency factors such as environmental strategy and firm size have a significant role in influencing the CEP-CFP relationship. The study's limitations, implications for practitioners and a future research agenda are also detailed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Nitrogen narcosis and tactile shape memory in low visibility.

PubMed

van Wijk, Charles H; Meintjes, W A J

2014-01-01

Commercial diving often occurs in low visibility, where divers are reliant on their tactile senses. This study examined the effect of nitrogen narcosis on tactile memory for shapes as well as the influence of psychological and biographical factors on this relationship. This crossover study tested 139 commercial divers in a dry hyperbaric chamber at 101.325 and 607.95 kPa (1 and 6 atmospheres absolute/atm abs). Divers memorized shapes while blindfolded, using their tactile senses only. Delayed recall was measured at the surface after each dive. Psychological and biographical data were also collected. A significant effect of hyperbaric pressure on tactile memory was demonstrated, and a further effect of sequence of testing found. Thus, divers' delayed shape recall deteriorated by 8% after learning material at depth, compared to learning on the surface. There were also significant but small effects of psychological and biographical markers on tactile memory performance, with lower trait anxiety associated with better recall, and lower education associated with poorer recall. The findings emphasize the importance of utilizing other forms of recording of events or objects at depth, particularly in conditions of low visibility during deeper diving, to aid memory encoding and subsequent recall at the surface.

Flexible wire-shaped strain sensor from cotton thread for human health and motion detection.

PubMed

Li, Yuan-Qing; Huang, Pei; Zhu, Wei-Bin; Fu, Shao-Yun; Hu, Ning; Liao, Kin

2017-03-21

In this work, a wire-shaped flexible strain sensor was fabricated by encapsulating conductive carbon thread (CT) with polydimethylsiloxane (PDMS) elastomer. The key strain sensitive material, CT, was prepared by pyrolysing cotton thread in N 2 atmosphere. The CT/PDMS composite wire shows a typical piezo-resistive behavior with high strain sensitivity. The gauge factors (GF) calculated at low strain of 0-4% and high strain of 8-10% are 8.7 and 18.5, respectively, which are much higher than that of the traditional metallic strain sensor (GF around 2). The wire-shaped CT/PDMS composite sensor shows excellent response to cyclic tensile loading within the strain range of 0-10%, the frequency range of 0.01-10 Hz, to up to 2000 cycles. The potential of the wire senor as wearable strain sensor is demonstrated by the finger motion and blood pulse monitoring. Featured by the low costs of cotton wire and PDMS resin, the simple structure and fabrication technique, as well as high performance with miniaturized size, the wire-shaped sensor based on CT/PDMS composite is believed to have a great potential for application in wearable electronics for human health and motion monitoring.

Effectiveness of stress release geometries on reducing residual stress in electroforming metal microstructure

NASA Astrophysics Data System (ADS)

Song, Chang; Du, Liqun; Zhao, Wenjun; Zhu, Heqing; Zhao, Wen; Wang, Weitai

2018-04-01

Micro electroforming, as a mature micromachining technology, is widely used to fabricate metal microdevices in micro electro mechanical systems (MEMS). However, large residual stress in the local positions of the micro electroforming layer often leads to non-uniform residual stress distributions, dimension accuracy defects and reliability issues during fabrication of the metal microdevice. To solve this problem, a novel design method of presetting stress release geometries in the topological structure of the metal microstructure is proposed in this paper. First, the effect of stress release geometries (circular shape, annular groove shape and rivet shape) on the residual stress in the metal microstructure was investigated by finite element modeling (FEM) analysis. Two evaluation parameters, stress concentration factor K T and stress non-uniformity factor δ were calculated. The simulation results show that presetting stress release geometries can effectively reduce and homogenize the residual stress in the metal microstructures were measured metal microstructure. By combined use with stress release geometries of annular groove shape and rivet shape, the stress concentration factor K T and the stress non-uniformity factor δ both decreased at a maximum of 49% and 53%, respectively. Meanwhile, the average residual stress σ avg decreased at a maximum of 20% from  -292.4 MPa to  -232.6 MPa. Then, micro electroforming experiments were carried out corresponding to the simulation models. The residual stresses in the metal microstructures were measured by micro Raman spectroscopy (MRS) method. The results of the experiment proved that the stress non-uniformity factor δ and the average residual stress σ avg also decreased at a maximum with the combination use of annular groove shape and rivet shape stress release geometries, which is in agreement with the results of FEM analysis. The stress non-uniformity factor δ has a maximum decrease of 49% and the average residual stress σ avg has a maximum decrease of 37% from  -257.0 MPa to  -162.0 MPa.

Effect of diffuser vane shape on the performance of a centrifugal compressor stage

NASA Astrophysics Data System (ADS)

Reddy, T. Ch Siva; Ramana Murty, G. V.; Prasad, M. V. S. S. S. M.

2014-04-01

The present paper reports the results of experimental investigations on the effect of diffuser vane shape on the performance of a centrifugal compressor stage. These studies were conducted on the chosen stage having a backward curved impeller of 500 mm tip diameter and 24.5 mm width and its design flow coefficient is ϕd=0.0535. Three different low solidity diffuser vane shapes namely uncambered aerofoil, constant thickness flat plate and circular arc cambered constant thickness plate were chosen as the variants for diffuser vane shape and all the three shapes have the same thickness to chord ratio (t/c=0.1). Flow coefficient, polytropic efficiency, total head coefficient, power coefficient and static pressure recovery coefficient were chosen as the parameters for evaluating the effect of diffuser vane shape on the stage performance. The results show that there is reasonable improvement in stage efficiency and total head coefficient with the use of the chosen diffuser vane shapes as compared to conventional vaneless diffuser. It is also noticed that the aero foil shaped LSD has shown better performance when compared to flat plate and circular arc profiles. The aerofoil vane shape of the diffuser blade is seen to be tolerant over a considerable range of incidence.

Multi-stage responsive 4D printed smart structure through varying geometric thickness of shape memory polymer

NASA Astrophysics Data System (ADS)

Teoh, Joanne Ee Mei; Zhao, Yue; An, Jia; Chua, Chee Kai; Liu, Yong

2017-12-01

Shape memory polymers (SMPs) have gained a presence in additive manufacturing due to their role in 4D printing. They can be printed either in multi-materials for multi-stage shape recovery or in a single material for single-stage shape recovery. When printed in multi-materials, material or material-based design is used as a controlling factor for multi-stage shape recovery. However, when printed in a single material, it is difficult to design multi-stage shape recovery due to the lack of a controlling factor. In this research, we explore the use of geometric thickness as a controlling factor to design smart structures possessing multi-stage shape recovery using a single SMP. L-shaped hinges with a thickness ranging from 0.3-2 mm were designed and printed in four different SMPs. The effect of thickness on SMP’s response time was examined via both experiment and finite element analysis using Ansys transient thermal simulation. A method was developed to accurately measure the response time in millisecond resolution. Temperature distribution and heat transfer in specimens during thermal activation were also simulated and discussed. Finally, a spiral square and an artificial flower consisting of a single SMP were designed and printed with appropriate thickness variation for the demonstration of a controlled multi-stage shape recovery. Experimental results indicated that smart structures printed using single material with controlled thickness parameters are able to achieve controlled shape recovery characteristics similar to those printed with multiple materials and uniform geometric thickness. Hence, the geometric parameter can be used to increase the degree of freedom in designing future smart structures possessing complex shape recovery characteristics.

Mass spectrometric analysis and aerodynamic properties of various types of combustion-related aerosol particles

NASA Astrophysics Data System (ADS)

Schneider, J.; Weimer, S.; Drewnick, F.; Borrmann, S.; Helas, G.; Gwaze, P.; Schmid, O.; Andreae, M. O.; Kirchner, U.

2006-12-01

Various types of combustion-related particles in the size range between 100 and 850 nm were analyzed with an aerosol mass spectrometer and a differential mobility analyzer. The measurements were performed with particles originating from biomass burning, diesel engine exhaust, laboratory combustion of diesel fuel and gasoline, as well as from spark soot generation. Physical and morphological parameters like fractal dimension, effective density, bulk density and dynamic shape factor were derived or at least approximated from the measurements of electrical mobility diameter and vacuum aerodynamic diameter. The relative intensities of the mass peaks in the mass spectra obtained from particles generated by a commercial diesel passenger car, by diesel combustion in a laboratory burner, and by evaporating and re-condensing lubrication oil were found to be very similar. The mass spectra from biomass burning particles show signatures identified as organic compounds like levoglucosan but also others which are yet unidentified. The aerodynamic behavior yielded a fractal dimension (Df) of 2.09 +/- 0.06 for biomass burning particles from the combustion of dry beech sticks, but showed values around three, and hence more compact particle morphologies, for particles from combustion of more natural oak. Scanning electron microscope images confirmed the finding that the beech combustion particles were fractal-like aggregates, while the oak combustion particles displayed a much more compact shape. For particles from laboratory combusted diesel fuel, a Df value of 2.35 was found, for spark soot particles, Df [approximate] 2.10. The aerodynamic properties of fractal-like particles from dry beech wood combustion indicate an aerodynamic shape factor [chi] that increases with electrical mobility diameter, and a bulk density of 1.92 g cm-3. An upper limit of [chi] [approximate] 1.2 was inferred for the shape factor of the more compact particles from oak combustion.

Using active shape modeling based on MRI to study morphologic and pitch-related functional changes affecting vocal structures and the airway.

PubMed

Miller, Nicola A; Gregory, Jennifer S; Aspden, Richard M; Stollery, Peter J; Gilbert, Fiona J

2014-09-01

The shape of the vocal tract and associated structures (eg, tongue and velum) is complicated and varies according to development and function. This variability challenges interpretation of voice experiments. Quantifying differences between shapes and understanding how vocal structures move in relation to each other is difficult using traditional linear and angle measurements. With statistical shape models, shape can be characterized in terms of independent modes of variation. Here, we build an active shape model (ASM) to assess morphologic and pitch-related functional changes affecting vocal structures and the airway. Using a cross-sectional study design, we obtained six midsagittal magnetic resonance images from 10 healthy adults (five men and five women) at rest, while breathing out, and while listening to, and humming low and high notes. Eighty landmark points were chosen to define the shape of interest and an ASM was built using these (60) images. Principal component analysis was used to identify independent modes of variation, and statistical analysis was performed using one-way repeated-measures analysis of variance. Twenty modes of variation were identified with modes 1 and 2 accounting for half the total variance. Modes 1 and 9 were significantly associated with humming low and high notes (P < 0.001) and showed coordinated changes affecting the cervical spine, vocal structures, and airway. Mode 2 highlighted wide structural variations between subjects. This study highlights the potential of active shape modeling to advance understanding of factors underlying morphologic and pitch-related functional variations affecting vocal structures and the airway in health and disease. Copyright © 2014 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

The Effect on Airplane Performance of the Factors That Must Be Considered in Applying Low-Drag Cowling to Radial Engines

NASA Technical Reports Server (NTRS)

Mcavoy, William H; Schey, Oscar W; Young, Alfred W

1933-01-01

This report presents the results of flight tests with three different airplanes using several types of low-drag cowling for radial air-cooled engines. The greater part of the tests were made with a Curtiss XF7Cc-1 (Sea Hawk) with a 410 horsepower. Wasp engine, using three fuselage nose shapes and six types of outer cowling. The six cowlings were: a narrow ring, a wide ring, a wide cowling similar in the original NACA cowling, a thick ring incorporating an exhaust collector, a single-surface cowling shaped like the outer surface of the exhaust-collector cowling, and polygon-ring cowling, of which the angle of the straight sections with the thrust line could be varied over a wide range.

Biometric assessment of prostate cancer's metastatic potential.

PubMed

Cooper, C R; Emmett, N; Harris-Hooker, S; Patterson, R; Cooke, D B

1994-01-01

Currently, no protocol exists that can assess the metastatic potential of prostate adenocarcinoma. The reason for this is partly due to the lack of information on cellular changes that result in a tumor cell's becoming metastatic. In this investigation, attempts were made to devise a method that correlated with the metastatic potential of AT-1, Mat-Lu, and Mat-LyLu cell lines of the Dunning R-3327 rat prostatic adenocarcinoma system. To accomplish this, we applied BioQuant biometric parameters, i.e., area, shape factor, and cell motility. AT-1 had a lower shape factor and a greater area as compared with the more highly metastatic Mat-Lu subline. No significant difference in area or shape factor was detected between the AT-1 cell line and the highly metastatic Mat-LyLu line. However, the lowly metastatic AT-1 line had less motility as compared with the Mat-Lu and Mat-LyLu lines. This study revealed that metastatic potential could be partially predicted via area and shape factor and accurately predicted via cell motility.

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

Asahina, Yuta; Kawashima, Tomohisa; Furukawa, Naoko

The formation mechanism of CO clouds observed with the NANTEN2 and Mopra telescopes toward the stellar cluster Westerlund 2 is studied by 3D magnetohydrodynamic simulations, taking into account the interstellar cooling. These molecular clouds show a peculiar shape composed of an arc-shaped cloud on one side of the TeV γ -ray source HESS J1023-575 and a linear distribution of clouds (jet clouds) on the other side. We propose that these clouds are formed by the interaction of a jet with clumps of interstellar neutral hydrogen (H i). By studying the dependence of the shape of dense cold clouds formed bymore » shock compression and cooling on the filling factor of H i clumps, we found that the density distribution of H i clumps determines the shape of molecular clouds formed by the jet–cloud interaction: arc clouds are formed when the filling factor is large. On the other hand, when the filling factor is small, molecular clouds align with the jet. The jet propagates faster in models with small filling factors.« less

SEIPS 2.0: A human factors framework for studying and improving the work of healthcare professionals and patients

PubMed Central

Holden, Richard J.; Carayon, Pascale; Gurses, Ayse P.; Hoonakker, Peter; Hundt, Ann Schoofs; Ozok, A. Ant; Rivera-Rodriguez, A. Joy

2013-01-01

Healthcare practitioners, patient safety leaders, educators, and researchers increasingly recognize the value of human factors/ergonomics and make use of the discipline’s person-centered models of sociotechnical systems. This paper first reviews one of the most widely used healthcare human factors systems models, the Systems Engineering Initiative for Patient Safety (SEIPS) model, and then introduces an extended model, “SEIPS 2.0.” SEIPS 2.0 incorporates three novel concepts into the original model: configuration, engagement, and adaptation. The concept of configuration highlights the dynamic, hierarchical, and interactive properties of sociotechnical systems, making it possible to depict how health-related performance is shaped at “a moment in time.” Engagement conveys that various individuals and teams can perform health-related activities separately and collaboratively. Engaged individuals often include patients, family caregivers, and other non-professionals. Adaptation is introduced as a feedback mechanism that explains how dynamic systems evolve in planned and unplanned ways. Key implications and future directions for human factors research in healthcare are discussed. PMID:24088063

32-channel 3 Tesla receive-only phased-array head coil with soccer-ball element geometry.

PubMed

Wiggins, G C; Triantafyllou, C; Potthast, A; Reykowski, A; Nittka, M; Wald, L L

2006-07-01

A 32-channel 3T receive-only phased-array head coil was developed for human brain imaging. The helmet-shaped array was designed to closely fit the head with individual overlapping circular elements arranged in patterns of hexagonal and pentagonal symmetry similar to that of a soccer ball. The signal-to-noise ratio (SNR) and noise amplification (g-factor) in accelerated imaging applications were quantitatively evaluated in phantom and human images and compared with commercially available head coils. The 32-channel coil showed SNR gains of up to 3.5-fold in the cortex and 1.4-fold in the corpus callosum compared to a (larger) commercial eight-channel head coil. The experimentally measured g-factor performance of the helmet array showed significant improvement compared to the eight-channel array (peak g-factor 59% and 26% of the eight-channel values for four- and fivefold acceleration). The performance of the arrays is demonstrated in high-resolution and highly accelerated brain images. Copyright (c) 2006 Wiley-Liss, Inc.

SARSCEST (human factors)

NASA Technical Reports Server (NTRS)

Parsons, H. Mcilvaine

1988-01-01

People interact with the processes and products of contemporary technology. Individuals are affected by these in various ways and individuals shape them. Such interactions come under the label 'human factors'. To expand the understanding of those to whom the term is relatively unfamiliar, its domain includes both an applied science and applications of knowledge. It means both research and development, with implications of research both for basic science and for development. It encompasses not only design and testing but also training and personnel requirements, even though some unwisely try to split these apart both by name and institutionally. The territory includes more than performance at work, though concentration on that aspect, epitomized in the derivation of the term ergonomics, has overshadowed human factors interest in interactions between technology and the home, health, safety, consumers, children and later life, the handicapped, sports and recreation education, and travel. Two aspects of technology considered most significant for work performance, systems and automation, and several approaches to these, are discussed.

Prediction of bedload sediment transport for heterogeneous sediments in shape

NASA Astrophysics Data System (ADS)

Durafour, Marine; Jarno, Armelle; Le Bot, Sophie; Lafite, Robert; Marin, François

2015-04-01

Key words: Particle shape, in-situ measurements, bedload transport, heterogeneous sediments Bedload sediment transport in the coastal area is a dynamic process mainly influenced by the type of hydrodynamic forcings involved (current and/or waves), the flow properties (velocity, viscosity, depth) and sediment heterogeneity (particle size, density, shape). Although particle shape is recognized to be a significant factor in the hydrodynamic behavior of grains, this parameter is not currently implemented in bedload transport formulations: firstly because the mechanisms of initiation of motion according to particle shape are still not fully understood, and secondly due to the difficulties in defining common shape parameters. In March 2011, a large panel of in-situ instruments was deployed on two sites in the Eastern English Channel, during the sea campaign MESFLUX11. Samples of the sediment cover available for transport are collected, during a slack period, per 2cm thick strata by divers and by using a Shipeck grab. Bedload discharges along a tidal cycle are also collected with a Delft Nile Sampler (DNS; Gaweesh and Van Rijn, 1992, 1994) on both sites. The first one is characterized by a sandy bed with a low size dispersion, while the other study area implies graded sediments from fine sands to granules. A detailed analysis of the data is performed to follow the evolution of in-situ bedload fluxes on the seabed for a single current. In-situ measurements are compared to existing formulations according to a single fraction approach, using the median diameter of the mixture, and a fractionwise approach, involving a discretization of the grading curve. Results emphasize the interest to oscillate between these two methods according to the dispersion in size of the site considered. The need to apply a hiding/exposure coefficient (Egiazaroff, 1965) and a hindrance factor (Kleinhans and Van Rijn, 2002) for size heterogeneous sediments is also clearly highlighted. A really good agreement is found for the non-uniform site between measured fluxes and predictions given by the Wu et al. (2000) model. However, some discrepancies still remain, especially for granules. Hundreds of pictures of grains composing the sediment cover and the bedload discharges are performed. Particle shapes are statistically characterized by three 2D coefficients (circularity, roundness and elongation) after an image processing with the ImageJ software. Present results show a preferential transport of the most circular sediment particles available for transport and reveal that the consideration of particle shape, through the integration of the circularity index in formulations, enhanced the estimations of bedload rates. A new adjustment of the Wu et al. (2000) formula is proposed, which improves significantly the model predictions, especially for granules. Durafour M, Jarno A, Le Bot S, Lafite R, Marin F (2014) Bedload transport for heterogeneous sediments. Environmental Fluid Mechanics. doi: 10.1007/s10652-014-9380-1

Characterization of the Modal Characteristics of Structures Operating in Dense Liquid Oxygen Turbopumps

NASA Technical Reports Server (NTRS)

Chiu, Joseph; Brown, Andrew M.

2017-01-01

A number of valuable conclusions can be drawn from this study. First, knockdown factors for a specific fluid are not constant but instead are dependent on the mode shape, although the largest this variability gets is about 10% for LOX, the densest fluid. The factors decrease the most for lower frequency shapes and less for higher ones. It follows, therefore, that mode number mismatch between air and fluid operation becomes not only possible, but common, as a knockdown factor for a particular mode shape may be higher than for another mode shape. Since this is a function of added mass, the mismatch is more prevalent for higher density fluids, but it initiates even for very low density ones. Another important conclusion reached is that it appears that the basic mode shapes of a structure do not change if it is fully symmetric, which includes its geometry and boundary conditions. There is some indication of small changes in the relative magnitudes within the mode shape. This conclusion is evident in the results from the cantilever rectangular plate and the inducer, which are not symmetric, and the fixed-fixed plate and the annular disk, which are. For non-symmetric structures, though, the mode shapes almost universally change for dense fluids, as shown by the very low MAC calculations. For the inducer in particular, the changes follow a trend of reduced parabolic and sine wavelengths with increasing density. It is critical to recognize the change in mode shape for several reasons. First, model updating with modal test becomes problematic if the shapes change. Second, design to avoid resonance is highly critical on the mode shape for modes other than the primary ones, as resonance is only a factor when the excitation shape matches the mode shape. Finally, application of the modal superposition method of forced response analysis is dependent on the use of accurate mode shapes. A more-refined assessment of the "knockdown" factor values and ranges than any previously reported in the literature for a realistic engineering structure is also presented in this paper. This data is of tremendous benefit for preliminary analysis and design, where a quick estimate is necessary. These results are important not just for rocket engine turbomachinery, but for water pumps and turbines, propellers, and any other structure operating in a heavy fluid with dynamic excitation. The clear avenue for future work for this endeavor is to expand the analytical techniques discussed in the literature to develop analytical expressions and justification for the mode shape changes and associated frequency knockdowns. These expressions must be able to accurately predict the functional relationship to the shapes, which will enable accurate tracing of the mode number from vacuum analysis (or testing in air) to analysis and operation in the intended fluid environment.

Shape Biased Low Power Spin Dependent Tunneling Magnetic Field Sensors

NASA Astrophysics Data System (ADS)

Tondra, Mark; Qian, Zhenghong; Wang, Dexin; Nordman, Cathy; Anderson, John

2001-10-01

Spin Dependent Tunneling (SDT) devices are leading candidates for inclusion in a number of Unattended Ground Sensor applications. Continued progress at NVE has pushed their performance to 1OOs of pT I rt. Hz 1 Hz. However, these sensors were designed to use an applied field from an on-chip coil to create an appropriate magnetic sensing configuration. The power required to generate this field (^100mW) is significantly greater than the power budget (^lmW) for a magnetic sensor in an Unattended Ground Sensor (UGS) application. Consequently, a new approach to creating an ideal sensing environment is required. One approach being used at NVE is "shape biasing." This means that the physical layout of the SDT sensing elements is such that the magnetization of the sensing film is correct even when no biasing field is applied. Sensors have been fabricated using this technique and show reasonable promise for UGS applications. Some performance trade-offs exist. The power is easily tinder 1 MW, but the sensitivity is typically lower by a factor of 10. This talk will discuss some of the design details of these sensors as well as their expected ultimate performance.

Analysis of a pico tubular-type hydro turbine performance by runner blade shape using CFD

NASA Astrophysics Data System (ADS)

Park, J. H.; Lee, N. J.; Wata, J. V.; Hwang, Y. C.; Kim, Y. T.; Lee, Y. H.

2012-11-01

There has been a considerable interest recently in the topic of renewable energy. This is primarily due to concerns about environmental impacts of fossil fuels. Moreover, fluctuating and rising oil prices, increase in demand, supply uncertainties and other factors have led to increased calls for alternative energy sources. Small hydropower, among other renewable energy sources, has been evaluated to have adequate development value because it is a clean, renewable and abundant energy resource. In addition, small hydropower has the advantage of low cost development by using rivers, agricultural reservoirs, sewage treatment plants, waterworks and water resources. The main concept of the tubular-type hydro turbine is based on the difference in water pressure levels in pipe lines, where the energy which was initially wasted by using a reducing valve at the pipeline of waterworks, is collected by turbine in the hydro power generator. In this study, in order to acquire the performance data of a pico tubular-type hydro turbine, the output power, head and efficiency characteristics by different runner blade shapes are examined. The pressure and velocity distributions with the variation of guide vane and runner vane angle on turbine performance are investigated by using a commercial CFD code.

Evaluation of particle shape and texture of mineral aggregates and their blends

DOT National Transportation Integrated Search

1992-05-01

Two important factors for minimizing rutting of hot mix asphalt (HMA) mixtures are: a) the fractured face count of aggregate when gravel is used as coarse aggregate, and b) the use of manufactured sand. Both these factors relate to the shape and text...

Crack-shape effects for indentation fracture toughness measurements

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

Smith, S.M.; Scattergood, R.O.

1992-02-01

Various methods to measure fracture toughness using indentation precracks were compared using soda-lime glass as a test material. In situ measurements of crack size as a function of applied stress allow both the toughness K[sub c] and the residual-stress factor [chi] to be independently determined. Analysis of the data showed that stress intensity factors based on classical half-penny crack shapes overestimate toughness values and produce an apparent R-curve effect. This is due to a constraint on crack shape imposed by primary lateral cracks in soda-lime glass. Models based on elliptical cracks were developed to account for the crack-shape effects.

An analysis of the wounding factors of four different shapes of fragments.

PubMed

Ma, Y Y; Feng, T S; Fu, R X; Li, M

1988-01-01

The wounding characteristics to a biological target of four typical shapes of fragments (square, triangular, cylindrical, and spherical) with masses of less than 1 gram and velocities between 460 and 1,500 m/s are studied in this paper. The following conclusions about the effects of the wounding factors, such as energy transfer, velocity, mass, and shape of fragment are presented: 1) For given target characteristics, the important wounding factors of fragments are impact velocity, mass, and shape, and of these velocity is the most important. 2) Besides direct effects, the fragment velocity has great influence on far-reaching, indirect wounding effects. When velocity increases, it not only increases the size of direct wound, but also the rate of indirect bone fracture. 3) The rate of energy transfer is affected by fragment shape, and it is also a decreasing function of mass. 4) Under the same conditions there are differences in wounding effectiveness among the four fragment shapes, the triangular with a comparatively high wounding effectiveness, followed by the square, cylindrical, and spherical. The types of wound channels are also different, the cylindrical and spherical making a "through" type, the square and triangular making a "blind-tube" type.

Links between global and local shape perception, coloured backgrounds, colour discrimination, and non-verbal IQ.

PubMed

Dore, Patricia; Dumani, Ardian; Wyatt, Geddes; Shepherd, Alex J

2018-03-16

This study explored associations between local and global shape perception on coloured backgrounds, colour discrimination, and non-verbal IQ (NVIQ). Five background colours were chosen for the local and global shape tasks that were tailored for the cone-opponent pathways early in the visual system (cardinal colour directions: L-M, loosely, reddish-greenish; and S-(L + M), or tritan colours, loosely, blueish-yellowish; where L, M and S refer to the long, middle and short wavelength sensitive cones). Participants also completed the Farnsworth-Munsell 100-hue test (FM100) to determine whether performance on the local and global shape tasks correlated with colour discrimination overall, or with performance on the L-M and tritan subsets of the FM100 test. Overall performance on the local and global shape tasks did correlate with scores on the FM100 tests, despite the colour of the background being irrelevant to the shape tasks. There were also significantly larger associations between scores for the L-M subset of the FM100 test, compared to the tritan subset, and accuracy on some of the shape tasks on the reddish, greenish and neutral backgrounds. Participants also completed the non-verbal components of the WAIS and the SPM+ version of Raven's progressive matrices, to determine whether performance on the FM100 test, and on the local and global shape tasks, correlated with NVIQ. FM100 scores correlated significantly with both WAIS and SPM+ scores. These results extend previous work that has indicated FM100 performance is not purely a measure of colour discrimination, but also involves aspects of each participant's NVIQ, such as the ability to attend to local and global aspects of the test, part-whole relationships, perceptual organisation and good visuomotor skills. Overall performance on the local and global shape tasks correlated only with the WAIS scores, not the SPM+. These results indicate that those aspects of NVIQ that engage spatial comprehension of local-global relationships and manual manipulation (WAIS), rather than more abstract reasoning (SPM+), are related to performance on the local and global shape tasks. Links are presented between various measures of NVIQ and performance on visual tasks, but they are currently seldom addressed in studies of either shape or colour perception. Further studies to explore these issues are recommended. Copyright © 2018 Elsevier Ltd. All rights reserved.

Improving the performance of AlGaN-based deep-ultraviolet light-emitting diodes using electron blocking layer with a heart-shaped graded Al composition

NASA Astrophysics Data System (ADS)

Kwon, M. R.; Park, T. H.; Lee, T. H.; Lee, B. R.; Kim, T. G.

2018-04-01

We propose a design for highly efficient AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) using a heart-shaped graded Al composition electron-blocking layer (EBL). This novel structure reduced downward band bending at the interface between the last quantum barrier and the EBL and flattened the electrostatic field in the interlayer between the barriers of the multi-quantum barrier EBL. Consequently, electron leakage was significantly suppressed and hole injection efficiency was found to have improved. The parameter values of simulation were extracted from the experimental data of the reference DUV LEDs. Using the SimuLED, we compared the electrical and optical properties of three structures with different Al compositions in the active region and the EBL. The internal quantum efficiency of the proposed structure was shown to exceed those of the reference DUV LEDs by a factor of 1.9. Additionally, the output power at 20 mA was found to increase by a factor of 2.1.

Aspheric design for manufacturability

NASA Astrophysics Data System (ADS)

Kreischer, Cody B.

2007-05-01

The experienced lens designer is well aware of the potential advantages aspherics can afford. Within the last few years, machines specifically designed for the CNC machining and polishing of glass aspheres have become commercially available through several manufacturers. This has brought down manufacturing cost to the point that designs incorporating aspheres can be used to reduce system cost compared to all spherical designs. (That is aspheres are no longer used just to save space and weight at the expense of cost.) Not all aspheres are equally manufacturable, however. Arbitrary choices at the beginning of a design can have major impact on manufacturing cost and limit final "as built" performance. This paper considers factors in designing ground and polished (as opposed to molded) glass aspheres which may not be obvious to even the experienced lens designer accustomed to using spherical surfaces or who has dealt with diamond turned aspheres. Factors considered include the surface shape, how the shape is specified, how the surface is to be tested and how it is toleranced. Emphasis will be placed on medium priced components where practical considerations are important.

Determination of sendust intrinsic permeability from microwave constitutive parameters of composites with sendust spheres and flakes

NASA Astrophysics Data System (ADS)

Starostenko, Sergey N.; Rozanov, Konstantin N.; Shiryaev, Artem O.; Shalygin, Alexander N.; Lagarkov, Andrey N.

2017-06-01

Intrinsic permeability of sendust alloys is determined from the measured microwave permittivity and permeability of composites filled with either spherical or flaky sendust powders. The permittivity and permeability measurements are performed applying the coaxial reflection-transmission technique in the 0.05 to 18 GHz frequency range. The effects of the filling factor, inclusion shape, and size on composite constitutive parameters are discussed. The permeability of metal inclusion is retrieved from the measured permeability of composites using a generalized Maxwell Garnett equation that accounts for the percolation threshold. The equation parameters are found by fitting the measured dependence of composite permittivity and permeability on frequency and filling. The inclusion dimensions calculated from the found parameters agree with the results of grain-size analyses. The alloy intrinsic permeability is retrieved from inclusion permeability with the account for skinning. The fitted frequency and damping factor of ferromagnetic resonance depend on the inclusion shape. The calculated reflectivity map of the flake-filled composite shows that sendust powders are promising fillers for interference suppressors and microwave absorbers at frequencies close to 1 GHz.

Deformation rate-, hold time-, and cycle-dependent shape-memory performance of Veriflex-E resin

NASA Astrophysics Data System (ADS)

McClung, Amber J. W.; Tandon, Gyaneshwar P.; Baur, Jeffery W.

2013-02-01

Shape-memory polymers have attracted great interest in recent years for application in reconfigurable structures (for instance morphing aircraft, micro air vehicles, and deployable space structures). However, before such applications can be attempted, the mechanical behavior of the shape-memory polymers must be thoroughly understood. The present study represents an assessment of viscous effects during multiple shape-memory cycles of Veriflex-E, an epoxy-based, thermally triggered shape-memory polymer resin. The experimental program is designed to explore the influence of multiple thermomechanical cycles on the shape-memory performance of Veriflex-E. The effects of the deformation rate and hold times at elevated temperature on the shape-memory behavior are also investigated.

High-strain slide-ring shape-memory polycaprolactone-based polyurethane.

PubMed

Wu, Ruiqing; Lai, Jingjuan; Pan, Yi; Zheng, Zhaohui; Ding, Xiaobin

2018-06-06

To enable shape-memory polymer networks to achieve recoverable high deformability with a simultaneous high shape-fixity ratio and shape-recovery ratio, novel semi-crystalline slide-ring shape-memory polycaprolactone-based polyurethane (SR-SMPCLU) with movable net-points constructed by a topologically interlocked slide-ring structure was designed and fabricated. The SR-SMPCLU not only exhibited good shape fixity, almost complete shape recovery, and a fast shape-recovery speed, it also showed an outstanding recoverable high-strain capacity with 95.83% Rr under a deformation strain of 1410% due to the pulley effect of the topological slide-ring structure. Furthermore, the SR-SMPCLU system maintained excellent shape-memory performance with increasing the training cycle numbers at 45% and even 280% deformation strain. The effects of the slide-ring cross-linker content, deformation strain, and successive shape-memory cycles on the shape-memory performance were investigated. A possible mechanism for the shape-memory effect of the SR-SMPCLU system is proposed.

Plasticity of the Binding Site of Renin: Optimized Selection of Protein Structures for Ensemble Docking.

PubMed

Strecker, Claas; Meyer, Bernd

2018-05-29

Protein flexibility poses a major challenge to docking of potential ligands in that the binding site can adopt different shapes. Docking algorithms usually keep the protein rigid and only allow the ligand to be treated as flexible. However, a wrong assessment of the shape of the binding pocket can prevent a ligand from adapting a correct pose. Ensemble docking is a simple yet promising method to solve this problem: Ligands are docked into multiple structures, and the results are subsequently merged. Selection of protein structures is a significant factor for this approach. In this work we perform a comprehensive and comparative study evaluating the impact of structure selection on ensemble docking. We perform ensemble docking with several crystal structures and with structures derived from molecular dynamics simulations of renin, an attractive target for antihypertensive drugs. Here, 500 ns of MD simulations revealed binding site shapes not found in any available crystal structure. We evaluate the importance of structure selection for ensemble docking by comparing binding pose prediction, ability to rank actives above nonactives (screening utility), and scoring accuracy. As a result, for ensemble definition k-means clustering appears to be better suited than hierarchical clustering with average linkage. The best performing ensemble consists of four crystal structures and is able to reproduce the native ligand poses better than any individual crystal structure. Moreover this ensemble outperforms 88% of all individual crystal structures in terms of screening utility as well as scoring accuracy. Similarly, ensembles of MD-derived structures perform on average better than 75% of any individual crystal structure in terms of scoring accuracy at all inspected ensembles sizes.

10 CFR Appendix K to Part 50 - ECCS Evaluation Models

Code of Federal Regulations, 2010 CFR

2010-01-01

... hypothetical accident. The modified Baroczy correlation (Baroczy, C. J., “A Systematic Correlation for Two... distribution shapes and peaking factors representing power distributions that may occur over the core lifetime must be studied. The selected combination of power distribution shape and peaking factor should be the...

10 CFR Appendix K to Part 50 - ECCS Evaluation Models

Code of Federal Regulations, 2011 CFR

2011-01-01

... hypothetical accident. The modified Baroczy correlation (Baroczy, C. J., “A Systematic Correlation for Two... distribution shapes and peaking factors representing power distributions that may occur over the core lifetime must be studied. The selected combination of power distribution shape and peaking factor should be the...

Video Games as Reconstructionist Sites of Learning in Art Education

ERIC Educational Resources Information Center

Parks, Nancy S.

2008-01-01

Art education has been in the midst of a transformation shaped by several factors, including changes in contemporary art theories, political and economic factors, and technological developments. Film, music videos, advertisements, video games and other forms of popular culture are shaping how students learn today. Discussions about video gaming…

[Foot growth and foot types in children and adolescents: a narrative review].

PubMed

Xu, Miaomiao; Wang, Lin

2017-08-01

Foot shape and size are important for footwear design and production. Information about important foot characteristics helps not only to improve shoe comfort but to maintain the proper physiological development of the feet. What's more, plenty of studies have suggested that the shape of the shoe must closely resemble the shape of the foot to create a properly fitted shoe. This means that the differences between various populations should be considered and that footwear should be designed according to the measurements of users. Childhood and adolescent are important periods of human growth. During these periods, foot shape changes with human growth and can be influenced by extrinsic factors. Therefore, the foot shape characteristics of children and adolescents should be investigated. The results from these investigations can contribute to developing appropriate shoe for children and adolescents, improving perceived comfort of children shoes and preventing pedopathy among children and adolescents. This review aims to discuss measuring methods of foot shape, types of foot shape, and factors influencing foot shape. The results of the review can provide recommendations for investigating growth development of foot shape and useful information for consumers and shoe manufacturers.

Experimental Investigation of Ice Accretion Effects on a Swept Wing

NASA Technical Reports Server (NTRS)

Wong, S. C.; Vargas, M.; Papadakis, M.; Yeong, H. W.; Potapczuk, M.

2005-01-01

An experimental investigation was conducted to study the effects of 2-, 5-, 10-, and 22.5-min ice accretions on the aerodynamic performance of a swept finite wing. The ice shapes tested included castings of ice accretions obtained from icing tests at the NASA Glenn Icing Research Tunnel (IRT) and simulated ice shapes obtained with the LEWICE 2.0 ice accretion code. The conditions used for the icing tests were selected to provide five glaze ice shapes with complete and incomplete scallop features and a small rime ice shape. The LEWICE ice shapes were defined for the same conditions as those used in the icing tests. All aerodynamic performance tests were conducted in the 7- x 10-ft Low-Speed Wind Tunnel Facility at Wichita State University. Six component force and moment measurements, aileron hinge moments, and surface pressures were obtained for a Reynolds number of 1.8 million based on mean aerodynamic chord and aileron deflections in the range of -15o to 20o. Tests were performed with the clean wing, six IRT ice shape castings, seven smooth LEWICE ice shapes, and seven rough LEWICE ice shapes. Roughness for the LEWICE ice shapes was simulated with 36-size grit. The experiments conducted showed that the glaze ice castings reduced the maximum lift coefficient of the clean wing by 11.5% to 93.6%, while the 5-min rime ice casting increased maximum lift by 3.4%. Minimum iced wing drag was 133% to 3533% greater with respect to the clean case. The drag of the iced wing near the clean wing stall angle of attack was 17% to 104% higher than that of the clean case. In general, the aileron remained effective in changing the lift of the clean and iced wings for all angles of attack and aileron deflections tested. Aileron hinge moments for the iced wing cases remained within the maximum and minimum limits defined by the clean wing hinge moments. Tests conducted with the LEWICE ice shapes showed that in general the trends in aerodynamic performance degradation of the wing with the simulated ice shapes were similar to those obtained with the IRT ice shape castings. However, in most cases, the ice castings resulted in greater aerodynamic performance losses than those obtained with the LEWICE ice shapes. For the majority of the LEWICE ice shapes, the addition of 36-size grit roughness to the smooth ice shapes increased aerodynamic performance losses.

Experimental investigation of the effect of inlet particle properties on the capture efficiency in an exhaust particulate filter

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

Viswanathan, Sandeep; Rothamer, David; Zelenyuk, Alla

The impact of inlet particle properties on the filtration performance of clean and particulate matter (PM) laden cordierite filter samples was evaluated using PM generated by a spark-ignition direct-injection (SIDI) engine fuelled with tier II EEE certification gasoline. Prior to the filtration experiments, a scanning mobility particle spectrometer (SMPS) was used to measure the electrical-mobility based particle size distribution (PSD) in the SIDI exhaust from distinct engine operating conditions. An advanced aerosol characterization system that comprised of a centrifugal particle mass analyser (CPMA), a differential mobility analyser (DMA), and a single particle mass spectrometer (SPLAT II) was used to obtainmore » additional information on the SIDI particulate, including particle composition, mass, and dynamic shape factors (DSFs) in the transition () and free-molecular () flow regimes. During the filtration experiments, real-time measurements of PSDs upstream and downstream of the filter sample were used to estimate the filtration performance and the total trapped mass within the filter using an integrated particle size distribution method. The filter loading process was paused multiple times to evaluate the filtration performance in the partially loaded state. The change in vacuum aerodynamic diameter () distribution of mass-selected particles was examined for flow through the filter to identify whether preferential capture of particles of certain shapes occurred in the filter. The filter was also probed using different inlet PSDs to understand their impact on particle capture within the filter sample. Results from the filtration experiment suggest that pausing the filter loading process and subsequently performing the filter probing experiments did not impact the overall evolution of filtration performance. Within the present distribution of particle sizes, filter efficiency was independent of particle shape potentially due to the diffusion-dominant filtration process. Particle mobility diameter and trapped mass within the filter appeared to be the dominant parameters that impacted filter performance.« less

WIDE AND THICK GRAIN 1, which encodes an otubain-like protease with deubiquitination activity, influences grain size and shape in rice.

PubMed

Huang, Ke; Wang, Dekai; Duan, Penggen; Zhang, Baolan; Xu, Ran; Li, Na; Li, Yunhai

2017-09-01

Grain size and shape are two crucial traits that influence grain yield and grain appearance in rice. Although several factors that affect grain size have been described in rice, the molecular mechanisms underlying the determination of grain size and shape are still elusive. In this study we report that WIDE AND THICK GRAIN 1 (WTG1) functions as an important factor determining grain size and shape in rice. The wtg1-1 mutant exhibits wide, thick, short and heavy grains and also shows an increased number of grains per panicle. WTG1 determines grain size and shape mainly by influencing cell expansion. WTG1 encodes an otubain-like protease, which shares similarity with human OTUB1. Biochemical analyses indicate that WTG1 is a functional deubiquitinating enzyme, and the mutant protein (wtg1-1) loses this deubiquitinating activity. WTG1 is expressed in developing grains and panicles, and the GFP-WTG1 fusion protein is present in the nucleus and cytoplasm. Overexpression of WTG1 results in narrow, thin, long grains due to narrow and long cells, further supporting the role of WTG1 in determining grain size and shape. Thus, our findings identify the otubain-like protease WTG1 to be an important factor that determines grain size and shape, suggesting that WTG1 has the potential to improve grain size and shape in rice. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

96-Channel receive-only head coil for 3 Tesla: design optimization and evaluation.

PubMed

Wiggins, Graham C; Polimeni, Jonathan R; Potthast, Andreas; Schmitt, Melanie; Alagappan, Vijay; Wald, Lawrence L

2009-09-01

The benefits and challenges of highly parallel array coils for head imaging were investigated through the development of a 3T receive-only phased-array head coil with 96 receive elements constructed on a close-fitting helmet-shaped former. We evaluated several designs for the coil elements and matching circuitry, with particular attention to sources of signal-to-noise ratio (SNR) loss, including various sources of coil loading and coupling between the array elements. The SNR and noise amplification (g-factor) in accelerated imaging were quantitatively evaluated in phantom and human imaging and compared to a 32-channel array built on an identical helmet-shaped former and to a larger commercial 12-channel head coil. The 96-channel coil provided substantial SNR gains in the distal cortex compared to the 12- and 32-channel coils. The central SNR for the 96-channel coil was similar to the 32-channel coil for optimum SNR combination and 20% lower for root-sum-of-squares combination. There was a significant reduction in the maximum g-factor for 96 channels compared to 32; for example, the 96-channel maximum g-factor was 65% of the 32-channel value for acceleration rate 4. The performance of the array is demonstrated in highly accelerated brain images.

Strategies to overcome photobleaching in algorithm-based adaptive optics for nonlinear in-vivo imaging.

PubMed

Caroline Müllenbroich, M; McGhee, Ewan J; Wright, Amanda J; Anderson, Kurt I; Mathieson, Keith

2014-01-01

We have developed a nonlinear adaptive optics microscope utilizing a deformable membrane mirror (DMM) and demonstrated its use in compensating for system- and sample-induced aberrations. The optimum shape of the DMM was determined with a random search algorithm optimizing on either two photon fluorescence or second harmonic signals as merit factors. We present here several strategies to overcome photobleaching issues associated with lengthy optimization routines by adapting the search algorithm and the experimental methodology. Optimizations were performed on extrinsic fluorescent dyes, fluorescent beads loaded into organotypic tissue cultures and the intrinsic second harmonic signal of these cultures. We validate the approach of using these preoptimized mirror shapes to compile a robust look-up table that can be applied for imaging over several days and through a variety of tissues. In this way, the photon exposure to the fluorescent cells under investigation is limited to imaging. Using our look-up table approach, we show signal intensity improvement factors ranging from 1.7 to 4.1 in organotypic tissue cultures and freshly excised mouse tissue. Imaging zebrafish in vivo, we demonstrate signal improvement by a factor of 2. This methodology is easily reproducible and could be applied to many photon starved experiments, for example fluorescent life time imaging, or when photobleaching is a concern.

Mechanisms and mechanics of shape loss during supersolidus liquid-phase sintering

NASA Astrophysics Data System (ADS)

Lal, Anand

Rapid sinter densification of relatively coarse prealloyed powders is possible by exceeding the solidus temperature in an approach termed supersolidus liquid phase sintering (SLPS). However, narrow processing windows for densification without distortion often limit this process. The liquid films at the grain boundaries that are responsible for densification also reduce the structural rigidity of components. Hence, components tend to slump under their own weight. Thus, the present study investigates shape loss during SLPS and rationalizes the processing and material factors with regard to separating densification from distortion. Experiments are performed on various prealloyed powders, including bronze, 316L stainless steel, and T15 tool steel. Differential thermal analysis, dilatometry, and in situ video imaging of sintering compacts are used to follow melting, densification, and distortion, respectively. Further, density and dimensional measurements are performed on sintered compacts. Results indicate a dependence of distortion on the sintering temperature and time, compact size, and melting behavior of the alloy. It is shown that the sintering temperature window, where high-density, precise components are obtained, can be widened for 316L stainless steel by boron addition. For the first time, a beam bending technique is used to measure the macroscopic apparent viscosity of semisolid bronze. The viscosity drops with temperature above the solidus and lies in the range of 108 to 106 Pa-s. Additionally, the in situ transverse rupture strength of bronze is measured to demonstrate the softening above the solidus temperature. Further, microstructural measurements are performed to enable correlation with the slumping behavior and viscosity. A model combining the deformation mechanisms, driving forces, and microstructural characteristics is developed to predict the conditions for densification and distortion onset. The microstructure is also correlated with the magnitude of shape loss and viscosity of a semisolid aggregate. A mechanistic model, based on the semisolid rheological characteristics, is developed to predict the magnitude and nature of shape loss. The model shows good correlation with experimental data for bronze. This study offers critical insight into SLPS and provides processing strategies for fabrication of high-density components without shape loss.

Midsagittal Brain Shape Correlation with Intelligence and Cognitive Performance

ERIC Educational Resources Information Center

Bruner, Emiliano; Martin-Loeches, Manuel; Burgaleta, Miguel; Colom, Roberto

2011-01-01

Brain shape might influence cognitive performance because of the relationships between functions, spatial organization, and differential volumetric development of cortical areas. Here we analyze the relationships between midsagittal brain shape variation and a set of basic psychological measures. Coordinates in 2D from 102 MRI-scanned young adult…

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

Guo, Yiting; Dong, Bin; Wang, Bing

Purpose: Effective and accurate segmentation of the aortic valve (AV) from sequenced ultrasound (US) images remains a technical challenge because of intrinsic factors of ultrasound images that impact the quality and the continuous changes of shape and position of segmented objects. In this paper, a novel shape-constraint gradient Chan-Vese (GCV) model is proposed for segmenting the AV from time serial echocardiography. Methods: The GCV model is derived by incorporating the energy of the gradient vector flow into a CV model framework, where the gradient vector energy term is introduced by calculating the deviation angle between the inward normal force ofmore » the evolution contour and the gradient vector force. The flow force enlarges the capture range and enhances the blurred boundaries of objects. This is achieved by adding a circle-like contour (constructed using the AV structure region as a constraint shape) as an energy item to the GCV model through the shape comparison function. This shape-constrained energy can enhance the image constraint force by effectively connecting separate gaps of the object edge as well as driving the evolution contour to quickly approach the ideal object. Because of the slight movement of the AV in adjacent frames, the initial constraint shape is defined by users, with the other constraint shapes being derived from the segmentation results of adjacent sequence frames after morphological filtering. The AV is segmented from the US images by minimizing the proposed energy function. Results: To evaluate the performance of the proposed method, five assessment parameters were used to compare it with manual delineations performed by radiologists (gold standards). Three hundred and fifteen images acquired from nine groups were analyzed in the experiment. The area-metric overlap error rate was 6.89% ± 2.88%, the relative area difference rate 3.94% ± 2.63%, the average symmetric contour distance 1.08 ± 0.43 mm, the root mean square symmetric contour distance 1.37 ± 0.52 mm, and the maximum symmetric contour distance was 3.57 ± 1.72 mm. Conclusions: Compared with the CV model, as a result of the combination of the gradient vector and neighborhood shape information, this semiautomatic segmentation method significantly improves the accuracy and robustness of AV segmentation, making it feasible for improved segmentation of aortic valves from US images that have fuzzy boundaries.« less

Discontinuum-Equivalent Continuum Analysis of the Stability of Tunnels in a Deep Coal Mine Using the Distinct Element Method

NASA Astrophysics Data System (ADS)

Shreedharan, Srisharan; Kulatilake, Pinnaduwa H. S. W.

2016-05-01

An imperative task for successful underground mining is to ensure the stability of underground structures. This is more so for deep excavations which may be under significantly high stresses. In this manuscript, we present stability studies on two tunnels, a horseshoe-shaped and an inverted arch-shaped tunnel, in a deep coal mine in China, performed using the 3DEC distinct element code. The rock mass mechanical property values for the tunnel shapes have been estimated through a back-analysis procedure using available field deformation data. The back-analysis has been carried out through a pseudo-time dependent support installation routine which incorporates the effect of time through a stress-relaxation mechanism. The back-analysis indicates that the rock mass cohesion, tensile strength, uniaxial compressive strength, and elastic modulus values are about 35-45 % of the corresponding intact rock property values. Additionally, the importance of incorporating stress relaxation before support installation has been illustrated through the increased support factor of safety and reduced grout failures. The calibrated models have been analyzed for different supported and unsupported cases to estimate the significance and adequacy of the current supports being used in the mine and to suggest a possible optimization. The effects of supports have been demonstrated using deformations and yield zones around the tunnels, and average factors of safety and grout failures of the supports. The use of longer supports and floor bolting has provided greater stability for the rock masses around the tunnels. Finally, a comparison between the two differently shaped tunnels establishes that the inverted arch tunnel may be more efficient in reducing roof sag and floor heave for the existing geo-mining conditions.

The effect of safety factor profile on transport in steady-state, high-performance scenarios

DOE PAGES

Holcomb, C. T.; Ferron, J. R.; Luce, T. C.; ...

2012-03-09

In this study, an analysis of the dependence of transport on the safety factor profile in high-performance, steady-state scenario discharges is presented. This is based on experimental scans of q 95 and q min taken with fixed β N, toroidal field, double-null plasma shape, divertor pumping, and electron cyclotron current drive input. The temperature and thermal diffusivity profiles were found to vary considerably with the q-profile, and these variations were significantly different for electrons and ions. With fixed q 95, both temperature profiles increase and broaden as q min is increased and the magnetic shear becomes low or negative inmore » the inner half radius, but these temperature profile changes are stronger for the electrons. Power balance calculations show the peak in the ion thermal diffusivity (χ i) at ρ – 0.6 – 0.8 increases with q 95 or q min.« less

Psychosocial correlates of disordered eating in female collegiate athletes: validation of the ATHLETE questionnaire.

PubMed

Hinton, Pamela S; Kubas, Karen L

2005-01-01

Female athletes may be at greater risk for disordered eating than their nonathletic peers, but the psychological antecedents of this dysfunctional behavior in athletes have yet to be elucidated. The objective of this study was to develop an athletics-oriented measure of psychological predictors of disordered eating and to test its initial reliability and validity. Female athletes from 3 National Collegiate Athletics Association (NCAA) Division I universities completed the ATHLETE, a written questionnaire designed to assess psychosocial factors associated with disordered eating in athletes. Five distinct and internally consistent factors (Drive for Thinness and Performance, Social Pressure on Eating, Performance Perfectionism, Social Pressure on Body Shape, and Team Trust) were positively associated with and predictive of disordered eating behaviors in female athletes. The ATHLETE is a reliable and valid measure of psychological predictors of disordered eating in athletics and will be useful in studying the etiology of disordered eating in female athletes.

Lunar Regolith Particle Shape Analysis

NASA Technical Reports Server (NTRS)

Kiekhaefer, Rebecca; Hardy, Sandra; Rickman, Douglas; Edmunson, Jennifer

2013-01-01

Future engineering of structures and equipment on the lunar surface requires significant understanding of particle characteristics of the lunar regolith. Nearly all sediment characteristics are influenced by particle shape; therefore a method of quantifying particle shape is useful both in lunar and terrestrial applications. We have created a method to quantify particle shape, specifically for lunar regolith, using image processing. Photomicrographs of thin sections of lunar core material were obtained under reflected light. Three photomicrographs were analyzed using ImageJ and MATLAB. From the image analysis measurements for area, perimeter, Feret diameter, orthogonal Feret diameter, Heywood factor, aspect ratio, sieve diameter, and sieve number were recorded. Probability distribution functions were created from the measurements of Heywood factor and aspect ratio.

Shaped saturation with inherent radiofrequency-power-efficient trajectory design in parallel transmission.

PubMed

Schneider, Rainer; Haueisen, Jens; Pfeuffer, Josef

2014-10-01

A target-pattern-driven (TD) trajectory design is introduced in combination with parallel transmit (pTX) radiofrequency (RF) pulses to provide localized suppression of unwanted signals. The design incorporates target-pattern and B1+ information to adjust denser sampling and coverage in k-space regions where the main pattern information lies. Based on this approach, two-dimensional RF spiral saturation pulses sensitive to RF power limits were applied in vivo for the first time. The TD method was compared with two state-of-the-art spiral design methods. Simulations at different spatial fidelities, acceleration factors and anatomical regions were carried out for an eight-channel pTX 3 Tesla (T) coil. Human in vivo experiments were performed on a two-channel pTX 3T scanner saturating shaped patterns in the brain, heart, and thoracic spine. Using the TD trajectory, RF pulse power can be substantially reduced by up to 34% compared with other trajectory designs with the same spatial accuracy. Local and global specific absorption rates are decreased in most cases. The TD trajectory design uses available a priori information to enhance RF power efficiency and spatial response of the RF pulses. Shaped saturation pulses show improved spatial accuracy and saturation performance. Thus, RF pulses can be designed more efficiently and can be further accelerated. Copyright © 2013 Wiley Periodicals, Inc.

Adaptive Shape Kernel-Based Mean Shift Tracker in Robot Vision System

PubMed Central

2016-01-01

This paper proposes an adaptive shape kernel-based mean shift tracker using a single static camera for the robot vision system. The question that we address in this paper is how to construct such a kernel shape that is adaptive to the object shape. We perform nonlinear manifold learning technique to obtain the low-dimensional shape space which is trained by training data with the same view as the tracking video. The proposed kernel searches the shape in the low-dimensional shape space obtained by nonlinear manifold learning technique and constructs the adaptive kernel shape in the high-dimensional shape space. It can improve mean shift tracker performance to track object position and object contour and avoid the background clutter. In the experimental part, we take the walking human as example to validate that our method is accurate and robust to track human position and describe human contour. PMID:27379165

Mean template for tensor-based morphometry using deformation tensors.

PubMed

Leporé, Natasha; Brun, Caroline; Pennec, Xavier; Chou, Yi-Yu; Lopez, Oscar L; Aizenstein, Howard J; Becker, James T; Toga, Arthur W; Thompson, Paul M

2007-01-01

Tensor-based morphometry (TBM) studies anatomical differences between brain images statistically, to identify regions that differ between groups, over time, or correlate with cognitive or clinical measures. Using a nonlinear registration algorithm, all images are mapped to a common space, and statistics are most commonly performed on the Jacobian determinant (local expansion factor) of the deformation fields. In, it was shown that the detection sensitivity of the standard TBM approach could be increased by using the full deformation tensors in a multivariate statistical analysis. Here we set out to improve the common space itself, by choosing the shape that minimizes a natural metric on the deformation tensors from that space to the population of control subjects. This method avoids statistical bias and should ease nonlinear registration of new subjects data to a template that is 'closest' to all subjects' anatomies. As deformation tensors are symmetric positive-definite matrices and do not form a vector space, all computations are performed in the log-Euclidean framework. The control brain B that is already the closest to 'average' is found. A gradient descent algorithm is then used to perform the minimization that iteratively deforms this template and obtains the mean shape. We apply our method to map the profile of anatomical differences in a dataset of 26 HIV/AIDS patients and 14 controls, via a log-Euclidean Hotelling's T2 test on the deformation tensors. These results are compared to the ones found using the 'best' control, B. Statistics on both shapes are evaluated using cumulative distribution functions of the p-values in maps of inter-group differences.

Shape variation in the least killifish: ecological associations of phenotypic variation and the effects of a common garden.

PubMed

Landy, J Alex; Travis, Joseph

2015-12-01

Studies of the adaptive significance of variation among conspecific populations often focus on a single ecological factor. However, habitats rarely differ in only a single ecological factor, creating a challenge for identifying the relative importance of the various ecological factors that might be maintaining local adaptation. Here we investigate the ecological factors associated with male body shape variation among nine populations of the poeciliid fish, Heterandria formosa, from three distinct habitats and combine those results with a laboratory study of three of those populations to assess the contributions of genetic and environmental influences to shape variation. Field-collected animals varied principally in three ways: the orientation of the gonopodium, the intromittent organ; the degree of body depth and streamlining; and the shape of the tail musculature. Fish collected in the spring season were larger and had a more anteriorly positioned gonopodium than fish collected in autumn. Fish collected from lotic springs were larger and more streamlined than those collected from lentic ponds or tidal marshes. Some of the variation in male shape among populations within habitats was associated with population-level variation in species richness, adult density, vegetative cover, predation risk, and female standard length. Population-level differences among males in body size, position of the gonopodium, and shape of the tail musculature were maintained among males reared in a common environment. In contrast, population variation in the degree of streamlining was eliminated when males were reared in a common environment. These results illustrate the complicated construction of multivariate phenotypic variation and suggest that different agents of selection have acted on different components of shape.

Ten-dimensional anthropomorphic arm control in a human brain-machine interface: difficulties, solutions, and limitations

NASA Astrophysics Data System (ADS)

Wodlinger, B.; Downey, J. E.; Tyler-Kabara, E. C.; Schwartz, A. B.; Boninger, M. L.; Collinger, J. L.

2015-02-01

Objective. In a previous study we demonstrated continuous translation, orientation and one-dimensional grasping control of a prosthetic limb (seven degrees of freedom) by a human subject with tetraplegia using a brain-machine interface (BMI). The current study, in the same subject, immediately followed the previous work and expanded the scope of the control signal by also extracting hand-shape commands from the two 96-channel intracortical electrode arrays implanted in the subject’s left motor cortex. Approach. Four new control signals, dictating prosthetic hand shape, replaced the one-dimensional grasping in the previous study, allowing the subject to control the prosthetic limb with ten degrees of freedom (three-dimensional (3D) translation, 3D orientation, four-dimensional hand shaping) simultaneously. Main results. Robust neural tuning to hand shaping was found, leading to ten-dimensional (10D) performance well above chance levels in all tests. Neural unit preferred directions were broadly distributed through the 10D space, with the majority of units significantly tuned to all ten dimensions, instead of being restricted to isolated domains (e.g. translation, orientation or hand shape). The addition of hand shaping emphasized object-interaction behavior. A fundamental component of BMIs is the calibration used to associate neural activity to intended movement. We found that the presence of an object during calibration enhanced successful shaping of the prosthetic hand as it closed around the object during grasping. Significance. Our results show that individual motor cortical neurons encode many parameters of movement, that object interaction is an important factor when extracting these signals, and that high-dimensional operation of prosthetic devices can be achieved with simple decoding algorithms. ClinicalTrials.gov Identifier: NCT01364480.

Optical properties of mineral dust aerosol including analysis of particle size, composition, and shape effects, and the impact of physical and chemical processing

NASA Astrophysics Data System (ADS)

Alexander, Jennifer Mary

Atmospheric mineral dust has a large impact on the earth's radiation balance and climate. The radiative effects of mineral dust depend on factors including, particle size, shape, and composition which can all be extremely complex. Mineral dust particles are typically irregular in shape and can include sharp edges, voids, and fine scale surface roughness. Particle shape can also depend on the type of mineral and can vary as a function of particle size. In addition, atmospheric mineral dust is a complex mixture of different minerals as well as other, possibly organic, components that have been mixed in while these particles are suspended in the atmosphere. Aerosol optical properties are investigated in this work, including studies of the effect of particle size, shape, and composition on the infrared (IR) extinction and visible scattering properties in order to achieve more accurate modeling methods. Studies of particle shape effects on dust optical properties for single component mineral samples of silicate clay and diatomaceous earth are carried out here first. Experimental measurements are modeled using T-matrix theory in a uniform spheroid approximation. Previous efforts to simulate the measured optical properties of silicate clay, using models that assumed particle shape was independent of particle size, have achieved only limited success. However, a model which accounts for a correlation between particle size and shape for the silicate clays offers a large improvement over earlier modeling approaches. Diatomaceous earth is also studied as an example of a single component mineral dust aerosol with extreme particle shapes. A particle shape distribution, determined by fitting the experimental IR extinction data, used as a basis for modeling the visible light scattering properties. While the visible simulations show only modestly good agreement with the scattering data, the fits are generally better than those obtained using more commonly invoked particle shape distributions. The next goal of this work is to investigate if modeling methods developed in the studies of single mineral components can be generalized to predict the optical properties of more authentic aerosol samples which are complex mixtures of different minerals. Samples of Saharan sand, Iowa loess, and Arizona road dust are used here as test cases. T-matrix based simulations of the authentic samples, using measured particle size distributions, empirical mineralogies, and a priori particle shape models for each mineral component are directly compared with the measured IR extinction spectra and visible scattering profiles. This modeling approach offers a significant improvement over more commonly applied models that ignore variations in particle shape with size or mineralogy and include only a moderate range of shape parameters. Mineral dust samples processed with organic acids and humic material are also studied in order to explore how the optical properties of dust can change after being aged in the atmosphere. Processed samples include quartz mixed with humic material, and calcite reacted with acetic and oxalic acid. Clear differences in the light scattering properties are observed for all three processed mineral dust samples when compared to the unprocessed mineral dust or organic salt products. These interactions result in both internal and external mixtures depending on the sample. In addition, the presence of these organic materials can alter the mineral dust particle shape. Overall, however, these results demonstrate the need to account for the effects of atmospheric aging of mineral dust on aerosol optical properties. Particle shape can also affect the aerodynamic properties of mineral dust aerosol. In order to account for these effects, the dynamic shape factor is used to give a measure of particle asphericity. Dynamic shape factors of quartz are measured by mass and mobility selecting particles and measuring their vacuum aerodynamic diameter. From this, dynamic shape factors in both the transition and vacuum regime can be derived. The measured dynamic shape factors of quartz agree quite well with the spheroidal shape distributions derived through studies of the optical properties.

Effect of Secondary Equilibria on the Adsorption of Ibuprofen Enantiomers on a Chiral Stationary Phase with a Grafted Antibiotic Eremomycin

NASA Astrophysics Data System (ADS)

Reshetova, E. N.; Asnin, L. D.; Kachmarsky, K.

2018-02-01

The chromatographic separation of ibuprofen enantiomers on a Nautilus-E chiral stationary phase with a grafted eremomycin antibiotic at high column loading is accompanied by distortion of the shape of chromatographic peaks. A model is proposed to explain this phenomenon. A number of factors are considered in the model: the ionization of ibuprofen in the mobile phase, the pH change in the mass transfer zone caused by ionization, and competitive adsorption involving buffer components. Simulations performed using this model within the theory of nonequilibrium chromatography allow the shape of chromatograms for large amounts of S- and R-ibuprofen samples to be predicted. The adsorption mechanism is found to be mainly ion-exchange. The contribution from the molecular adsorption of ibuprofen to the total retention is shown to be several percent.

Arbitrary Shape Deformation in CFD Design

NASA Technical Reports Server (NTRS)

Landon, Mark; Perry, Ernest

2014-01-01

Sculptor(R) is a commercially available software tool, based on an Arbitrary Shape Design (ASD), which allows the user to perform shape optimization for computational fluid dynamics (CFD) design. The developed software tool provides important advances in the state-of-the-art of automatic CFD shape deformations and optimization software. CFD is an analysis tool that is used by engineering designers to help gain a greater understanding of the fluid flow phenomena involved in the components being designed. The next step in the engineering design process is to then modify, the design to improve the components' performance. This step has traditionally been performed manually via trial and error. Two major problems that have, in the past, hindered the development of an automated CFD shape optimization are (1) inadequate shape parameterization algorithms, and (2) inadequate algorithms for CFD grid modification. The ASD that has been developed as part of the Sculptor(R) software tool is a major advancement in solving these two issues. First, the ASD allows the CFD designer to freely create his own shape parameters, thereby eliminating the restriction of only being able to use the CAD model parameters. Then, the software performs a smooth volumetric deformation, which eliminates the extremely costly process of having to remesh the grid for every shape change (which is how this process had previously been achieved). Sculptor(R) can be used to optimize shapes for aerodynamic and structural design of spacecraft, aircraft, watercraft, ducts, and other objects that affect and are affected by flows of fluids and heat. Sculptor(R) makes it possible to perform, in real time, a design change that would manually take hours or days if remeshing were needed.

Ice Accretion with Varying Surface Tension

NASA Technical Reports Server (NTRS)

Bilanin, Alan J.; Anderson, David N.

1995-01-01

During an icing encounter of an aircraft in flight, super-cooled water droplets impinging on an airfoil may splash before freezing. This paper reports tests performed to determine if this effect is significant and uses the results to develop an improved scaling method for use in icing test facilities. Simple laboratory tests showed that drops splash on impact at the Reynolds and Weber numbers typical of icing encounters. Further confirmation of droplet splash came from icing tests performed in the NaSA Lewis Icing Research Tunnel (IRT) with a surfactant added to the spray water to reduce the surface tension. The resulting ice shapes were significantly different from those formed when no surfactant was added to the water. These results suggested that the droplet Weber number must be kept constant to properly scale icing test conditions. Finally, the paper presents a Weber-number-based scaling method and reports results from scaling tests in the IRT in which model size was reduced up to a factor of 3. Scale and reference ice shapes are shown which confirm the effectiveness of this new scaling method.

Constant- q data representation in Neutron Compton scattering on the VESUVIO spectrometer

NASA Astrophysics Data System (ADS)

Senesi, R.; Pietropaolo, A.; Andreani, C.

2008-09-01

Standard data analysis on the VESUVIO spectrometer at ISIS is carried out within the Impulse Approximation framework, making use of the West scaling variable y. The experiments are performed using the time-of-flight technique with the detectors positioned at constant scattering angles. Line shape analysis is routinely performed in the y-scaling framework, using two different (and equivalent) approaches: (1) fitting the parameters of the recoil peaks directly to fixed-angle time-of-flight spectra; (2) transforming the time-of-flight spectra into fixed-angle y spectra, referred to as the Neutron Compton Profiles, and then fitting the line shape parameters. The present work shows that scattering signals from different fixed-angle detectors can be collected and rebinned to obtain Neutron Compton Profiles at constant wave vector transfer, q, allowing for a suitable interpretation of data in terms of the dynamical structure factor, S(q,ω). The current limits of applicability of such a procedure are discussed in terms of the available q-range and relative uncertainties for the VESUVIO experimental set up and of the main approximations involved.

Towards next generation 3D cameras

NASA Astrophysics Data System (ADS)

Gupta, Mohit

2017-03-01

We are in the midst of a 3D revolution. Robots enabled by 3D cameras are beginning to autonomously drive cars, perform surgeries, and manage factories. However, when deployed in the real-world, these cameras face several challenges that prevent them from measuring 3D shape reliably. These challenges include large lighting variations (bright sunlight to dark night), presence of scattering media (fog, body tissue), and optically complex materials (metal, plastic). Due to these factors, 3D imaging is often the bottleneck in widespread adoption of several key robotics technologies. I will talk about our work on developing 3D cameras based on time-of-flight and active triangulation that addresses these long-standing problems. This includes designing `all-weather' cameras that can perform high-speed 3D scanning in harsh outdoor environments, as well as cameras that recover shape of objects with challenging material properties. These cameras are, for the first time, capable of measuring detailed (<100 microns resolution) scans in extremely demanding scenarios with low-cost components. Several of these cameras are making a practical impact in industrial automation, being adopted in robotic inspection and assembly systems.

Comprehensive modelling and simulation of cylindrical nanoparticles manipulation by using a virtual reality environment.

PubMed

Korayem, Moharam Habibnejad; Hoshiar, Ali Kafash; Ghofrani, Maedeh

2017-08-01

With the expansion of nanotechnology, robots based on atomic force microscope (AFM) have been widely used as effective tools for displacing nanoparticles and constructing nanostructures. One of the most limiting factors in AFM-based manipulation procedures is the inability of simultaneously observing the controlled pushing and displacing of nanoparticles while performing the operation. To deal with this limitation, a virtual reality environment has been used in this paper for observing the manipulation operation. In the simulations performed in this paper, first, the images acquired by the atomic force microscope have been processed and the positions and dimensions of nanoparticles have been determined. Then, by dynamically modelling the transfer of nanoparticles and simulating the critical force-time diagrams, a controlled displacement of nanoparticles has been accomplished. The simulations have been further developed for the use of rectangular, V-shape and dagger-shape cantilevers. The established virtual reality environment has made it possible to simulate the manipulation of biological particles in a liquid medium. Copyright © 2017 Elsevier Inc. All rights reserved.

Subjective Significance Shapes Arousal Effects on Modified Stroop Task Performance: A Duality of Activation Mechanisms Account.

PubMed

Imbir, Kamil K

2016-01-01

Activation mechanisms such as arousal are known to be responsible for slowdown observed in the Emotional Stroop and modified Stroop tasks. Using the duality of mind perspective, we may conclude that both ways of processing information (automatic or controlled) should have their own mechanisms of activation, namely, arousal for an experiential mind, and subjective significance for a rational mind. To investigate the consequences of both, factorial manipulation was prepared. Other factors that influence Stroop task processing such as valence, concreteness, frequency, and word length were controlled. Subjective significance was expected to influence arousal effects. In the first study, the task was to name the color of font for activation charged words. In the second study, activation charged words were, at the same time, combined with an incongruent condition of the classical Stroop task around a fixation point. The task was to indicate the font color for color-meaning words. In both studies, subjective significance was found to shape the arousal impact on performance in terms of the slowdown reduction for words charged with subjective significance.

Shape of the human nasal cavity promotes retronasal smell

NASA Astrophysics Data System (ADS)

Trastour, Sophie; Melchionna, Simone; Mishra, Shruti; Zwicker, David; Lieberman, Daniel E.; Kaxiras, Efthimios; Brenner, Michael P.

2015-11-01

Humans are exceptionally good at perceiving the flavor of food. Flavor includes sensory input from taste receptors but is dominated by olfactory (smell) receptors. To smell food while eating, odors must be transported to the nasal cavity during exhalation. Olfactory performance of this retronasal route depends, among other factors, on the position of the olfactory receptors and the shape of the nasal cavity. One biological hypothesis is that the derived configuration of the human nasal cavity has resulted in a greater capacity for retronasal smell, hence enhanced flavor perception. We here study the air flow and resulting odor deposition as a function of the nasal geometry and the parameters of exhalation. We perform computational fluid dynamics simulations in realistic geometries obtained from CT scans of humans. Using the resulting flow fields, we then study the deposition of tracer particles in the nasal cavity. Additionally, we derive scaling laws for the odor deposition rate as a function of flow parameters and geometry using boundary layer theory. These results allow us to assess which changes in the evolution of the human nose led to significant improvements of retronasal smell.

Effect on injuries of assigning shoes based on foot shape in air force basic training.

PubMed

Knapik, Joseph J; Brosch, Lorie C; Venuto, Margaret; Swedler, David I; Bullock, Steven H; Gaines, Lorraine S; Murphy, Ryan J; Tchandja, Juste; Jones, Bruce H

2010-01-01

This study examined whether assigning running shoes based on the shape of the bottom of the foot (plantar surface) influenced injury risk in Air Force Basic Military Training (BMT) and examined risk factors for injury in BMT. Data were collected from BMT recruits during 2007; analysis took place during 2008. After foot examinations, recruits were randomly consigned to either an experimental group (E, n=1042 men, 375 women) or a control group (C, n=913 men, 346 women). Experimental group recruits were assigned motion control, stability, or cushioned shoes for plantar shapes indicative of low, medium, or high arches, respectively. Control group recruits received a stability shoe regardless of plantar shape. Injuries during BMT were determined from outpatient visits provided from the Defense Medical Surveillance System. Other injury risk factors (fitness, smoking, physical activity, prior injury, menstrual history, and demographics) were obtained from a questionnaire, existing databases, or BMT units. Multivariate Cox regression controlling for other risk factors showed little difference in injury risk between the groups among men (hazard ratio [E/C]=1.11, 95% CI=0.89-1.38) or women (hazard ratio [E/C]=1.20, 95% CI= 0.90-1.60). Independent injury risk factors among both men and women included low aerobic fitness and cigarette smoking. This prospective study demonstrated that assigning running shoes based on the shape of the plantar surface had little influence on injury risk in BMT even after controlling for other injury risk factors. Published by Elsevier Inc.

The Signs B [Image Omitted] and B-Bent [Image Omitted] in Israeli Sign Language According to the Theory of Phonology as Human Behavior

ERIC Educational Resources Information Center

Fuks, Orit; Tobin, Yishai

2008-01-01

The purpose of the present research is to examine which of the two factors: (1) the iconic-semiotic factor; or (2) the human-phonetic factor is more relevant in explaining the appearance and distribution of the hand shape B-bent in Israeli Sign Language (ISL). The B-bent shape has been the subject of much attention in sign language research…

Electrical properties of Schottky barrier diodes fabricated on (001) β-Ga2O3 substrates with crystal defects

NASA Astrophysics Data System (ADS)

Oshima, Takayoshi; Hashiguchi, Akihiro; Moribayashi, Tomoya; Koshi, Kimiyoshi; Sasaki, Kohei; Kuramata, Akito; Ueda, Osamu; Oishi, Toshiyuki; Kasu, Makoto

2017-08-01

The electrical properties of Schottky barrier diodes (SBDs) on a (001) β-Ga2O3 substrate were characterized and correlated with wet etching-revealed crystal defects below the corresponding Schottky contacts. The etching process revealed etched grooves and etched pits, indicating the presence of line-shaped voids and small defects near the surface, respectively. The electrical properties (i.e., leakage currents, ideality factor, and barrier height) exhibited almost no correlation with the density of the line-shaped voids. This very weak correlation was reasonable considering the parallel positional relation between the line-shaped voids extending along the [010] direction and the (001) basal plane in which the voids are rarely exposed on the initial surface in contact with the Schottky metals. The distribution of small defects and SBDs with unusually large leakage currents showed similar patterns on the substrate, suggesting that these defects were responsible for the onset of fatal leak paths. These results will encourage studies on crystal defect management of (001) β-Ga2O3 substrates for the fabrication of devices with enhanced performance using these substrates.

Experiment M115: Special hematologic effects: Dynamic changes in red cell shape in response to the space-flight environment

NASA Technical Reports Server (NTRS)

Kimzey, S. L.; Burns, L. C.; Fischer, C. L.

1974-01-01

The significance of the transformations in red cell shape observed during the Skylab study must be considered relative to the limitation of man's participation in extended space flight missions. The results of this one study are not conclusive with respect to this question. Based on these examinations of red cells in normal, healthy men and based on other Skylab experiment data relative to the functional capacity of the red cells in vitro and the performance capacity of man as an integrated system, the changes observed would not appear to be the limiting factor in determining man's stay in space. However, the results of this experiment and the documented red cell mass loss during space flight raise serious questions at this time relative to the selection criteria utilized for passengers and crews of future space flights. Until the specific cause and impact of the red cell shape change on cell survival in vivo can be resolved, individuals with diagnosed hematologic abnormalities should not be considered as prime candidates for missions, especially those of longer duration.

Impact of building configuration on air quality in street canyon

NASA Astrophysics Data System (ADS)

Xie, Xiaomin; Huang, Zhen; Wang, Jia-song

The objective of this study is to provide a simulation of emissions from vehicle exhausts in a street canyon within an urban environment. Standard, RNG and Chen-Kim k- ɛ turbulence models are compared with the wind tunnel measured data for optimization of turbulence model. In the first approach, the investigation is made into the effect of the different roof shapes and ambient building structures. The results indicate that the in-canyon vortex dynamics (e.g. vortex orientation) and the characteristics of pollutant dispersion are dependent on the roof shapes and ambient building structures strongly. A second set of calculations for a three-dimensional simulation of the street canyon setup was performed to investigate the influence of building geometry on pollutant dispersion. The validation of the numerical model was evaluated using an extensive experimental database obtained from the atmospheric boundary layer wind tunnel at the Meteorological Institute of Hamburg University, Germany (Studie on different roof geometries in a simplified urban environment, 1995). The studies give evidence that roof shapes, the ambient building configurations and building geometries are important factors determining the flow patterns and pollutant dispersion in street canyon.

The Effect of Pulse Shaping QPSK on Bandwidth Efficiency

NASA Technical Reports Server (NTRS)

Purba, Josua Bisuk Mubyarto; Horan, Shelia

1997-01-01

This research investigates the effect of pulse shaping QPSK on bandwidth efficiency over a non-linear channel. This investigation will include software simulations and the hardware implementation. Three kinds of filters: the 5th order Butterworth filter, the 3rd order Bessel filter and the Square Root Raised Cosine filter with a roll off factor (alpha) of 0.25,0.5 and 1, have been investigated as pulse shaping filters. Two different high power amplifiers, one a Traveling Wave Tube Amplifier (TWTA) and the other a Solid State Power Amplifier (SSPA) have been investigated in the hardware implementation. A significant improvement in the bandwidth utilization (rho) for the filtered data compared to unfiltered data through the non-linear channel is shown in the results. This method promises strong performance gains in a bandlimited channel when compared to unfiltered systems. This work was conducted at NMSU in the Center for Space Telemetering, and Telecommunications Systems in the Klipsch School of Electrical and Computer Engineering Department and is supported by a grant from the National Aeronautics and Space Administration (NASA) NAG5-1491.

An analysis of stepped trapezoidal-shaped microcantilever beams for MEMS-based devices

NASA Astrophysics Data System (ADS)

Ashok, Akarapu; Gangele, Aparna; Pal, Prem; Pandey, Ashok Kumar

2018-07-01

Microcantilever beams are the most widely used mechanical elements in the design and fabrication of MEMS/NEMS-based sensors and actuators. In this work, we have proposed a new microcantilever beam design based on a stepped trapezoidal-shaped microcantilever. Single-, double-, triple- and quadruple-stepped trapezoidal-shaped microcantilever beams along with conventional rectangular-shaped microcantilever beams were analysed experimentally, numerically and analytically. The microcantilever beams were fabricated from silicon dioxide material using wet bulk micromachining in 25 wt% TMAH. The length, width and thickness of the microcantilever beams were fixed at 200, 40 and 0.96 µm, respectively. A laser vibrometer was utilized to measure the resonance frequency and Q-factor of the microcantilever beams in vacuum as well as in ambient conditions. Furthermore, finite element analysis software, ANSYS, was employed to numerically analyse the resonance frequency, maximum deflection and torsional end rotation of all the microcantilever beam designs. The analytical and numerical resonance frequencies are found to be in good agreement with the experimental resonance frequencies. In the stepped trapezoidal-shaped microcantilever beams with an increasing number of steps, the Q-factor, maximum deflection and torsional end rotation were improved, whereas the resonance frequency was slightly reduced. Nevertheless, the resonance frequency is higher than the basic rectangular-shaped microcantilever beam. The observed quality factor, maximum deflection and torsional end rotation for a quadruple-stepped trapezoidal-shaped microcantilever are 38%, 41% and 52%, respectively, which are higher than those of conventional rectangular-shaped microcantilever beams. Furthermore, for an applied concentrated mass of 1 picogram on the cantilever surface, a greater shift in frequency is obtained for all the stepped trapezoidal-shaped microcantilever beam designs compared to the conventional rectangular microcantilever beam.

Predicting conformational ensembles and genome-wide transcription factor binding sites from DNA sequences.

PubMed

Andrabi, Munazah; Hutchins, Andrew Paul; Miranda-Saavedra, Diego; Kono, Hidetoshi; Nussinov, Ruth; Mizuguchi, Kenji; Ahmad, Shandar

2017-06-22

DNA shape is emerging as an important determinant of transcription factor binding beyond just the DNA sequence. The only tool for large scale DNA shape estimates, DNAshape was derived from Monte-Carlo simulations and predicts four broad and static DNA shape features, Propeller twist, Helical twist, Minor groove width and Roll. The contributions of other shape features e.g. Shift, Slide and Opening cannot be evaluated using DNAshape. Here, we report a novel method DynaSeq, which predicts molecular dynamics-derived ensembles of a more exhaustive set of DNA shape features. We compared the DNAshape and DynaSeq predictions for the common features and applied both to predict the genome-wide binding sites of 1312 TFs available from protein interaction quantification (PIQ) data. The results indicate a good agreement between the two methods for the common shape features and point to advantages in using DynaSeq. Predictive models employing ensembles from individual conformational parameters revealed that base-pair opening - known to be important in strand separation - was the best predictor of transcription factor-binding sites (TFBS) followed by features employed by DNAshape. Of note, TFBS could be predicted not only from the features at the target motif sites, but also from those as far as 200 nucleotides away from the motif.

A FORTRAN Computer Program to Perform Goodness of Fit Testing on Empirical Data.

DTIC Science & Technology

1979-06-01

11 9. Mesokurtic Shape ....... ................. 1210. Platykurtic Shape ..... .. ................ 12 11. Leptokurtic Shape...distribution is platykurtic and if K is greater than 3, the distribution is described as leptokurtic. Figures 9, 10, and 11 illustrate mesokurtic... platykurtic , and leptokurtic shapes (8). Figure 9 Figure 10 Figure 11 Mesokurtic Shape Platykurtic Shape Leptokurtic Shape The population parameters for

Shape Adaptive, Robust Iris Feature Extraction from Noisy Iris Images

PubMed Central

Ghodrati, Hamed; Dehghani, Mohammad Javad; Danyali, Habibolah

2013-01-01

In the current iris recognition systems, noise removing step is only used to detect noisy parts of the iris region and features extracted from there will be excluded in matching step. Whereas depending on the filter structure used in feature extraction, the noisy parts may influence relevant features. To the best of our knowledge, the effect of noise factors on feature extraction has not been considered in the previous works. This paper investigates the effect of shape adaptive wavelet transform and shape adaptive Gabor-wavelet for feature extraction on the iris recognition performance. In addition, an effective noise-removing approach is proposed in this paper. The contribution is to detect eyelashes and reflections by calculating appropriate thresholds by a procedure called statistical decision making. The eyelids are segmented by parabolic Hough transform in normalized iris image to decrease computational burden through omitting rotation term. The iris is localized by an accurate and fast algorithm based on coarse-to-fine strategy. The principle of mask code generation is to assign the noisy bits in an iris code in order to exclude them in matching step is presented in details. An experimental result shows that by using the shape adaptive Gabor-wavelet technique there is an improvement on the accuracy of recognition rate. PMID:24696801

Shape adaptive, robust iris feature extraction from noisy iris images.

PubMed

Ghodrati, Hamed; Dehghani, Mohammad Javad; Danyali, Habibolah

2013-10-01

In the current iris recognition systems, noise removing step is only used to detect noisy parts of the iris region and features extracted from there will be excluded in matching step. Whereas depending on the filter structure used in feature extraction, the noisy parts may influence relevant features. To the best of our knowledge, the effect of noise factors on feature extraction has not been considered in the previous works. This paper investigates the effect of shape adaptive wavelet transform and shape adaptive Gabor-wavelet for feature extraction on the iris recognition performance. In addition, an effective noise-removing approach is proposed in this paper. The contribution is to detect eyelashes and reflections by calculating appropriate thresholds by a procedure called statistical decision making. The eyelids are segmented by parabolic Hough transform in normalized iris image to decrease computational burden through omitting rotation term. The iris is localized by an accurate and fast algorithm based on coarse-to-fine strategy. The principle of mask code generation is to assign the noisy bits in an iris code in order to exclude them in matching step is presented in details. An experimental result shows that by using the shape adaptive Gabor-wavelet technique there is an improvement on the accuracy of recognition rate.

Sociotechnical factors influencing unsafe use of hospital information systems: A qualitative study in Malaysian government hospitals.

PubMed

Salahuddin, Lizawati; Ismail, Zuraini; Hashim, Ummi Rabaah; Raja Ikram, Raja Rina; Ismail, Nor Haslinda; Naim Mohayat, Mohd Hariz

2018-03-01

The objective of this study is to identify factors influencing unsafe use of hospital information systems in Malaysian government hospitals. Semi-structured interviews with 31 medical doctors in three Malaysian government hospitals implementing total hospital information systems were conducted between March and May 2015. A thematic qualitative analysis was performed on the resultant data to deduce the relevant themes. A total of five themes emerged as the factors influencing unsafe use of a hospital information system: (1) knowledge, (2) system quality, (3) task stressor, (4) organization resources, and (5) teamwork. These qualitative findings highlight that factors influencing unsafe use of a hospital information system originate from multidimensional sociotechnical aspects. Unsafe use of a hospital information system could possibly lead to the incidence of errors and thus raises safety risks to the patients. Hence, multiple interventions (e.g. technology systems and teamwork) are required in shaping high-quality hospital information system use.

High Performance Computing (HPC)-Enabled Computational Study on the Feasibility of using Shape Memory Alloys for Gas Turbine Blade Actuation

DTIC Science & Technology

2016-11-01

Feasibility of using Shape Memory Alloys for Gas Turbine Blade Actuation by Kathryn Esham, Luis Bravo, Anindya Ghoshal, Muthuvel Murugan, and Michael...Computational Study on the Feasibility of using Shape Memory Alloys for Gas Turbine Blade Actuation by Luis Bravo, Anindya Ghoshal, Muthuvel...High Performance Computing (HPC)-Enabled Computational Study on the Feasibility of using Shape Memory Alloys for Gas Turbine Blade Actuation 5a

[The monophasic pattern in oral glucose tolerance test as a predictive risk factor of type 2 diabetes in obese paediatric patients].

PubMed

Herrera-Martínez, Aura D; Enes, Patricia; Martín-Frías, María; Roldán, Belén; Yelmo, Rosa; Barrio, Raquel

2017-10-01

The onset of obesity at young ages is strongly associated with the early development of type 2diabetes (T2D). The shape of the curves of glucose and insulin curves during an oral glucose tolerance test (OGTT) could predict the risk of developing T2D. To analyse the morphology of the OGTT and determine T2D risk factors in a mainly Caucasian population of children and adolescents. Observational retrospective study including 588 patients (309 males, 279 females) with a mean age of 11.1±2years, and of whom 90.3% were Caucasian. Risk factors for T2D were compared in patients with a monophasic or biphasic pattern during the performance of an OGTT, as well as anthropometric and biochemical variables, insulin resistance, and beta-cell function. The shape of the glucose curve was monophasic in 50.2% of patients (50.8% male), biphasic in 48.5% (47.6% males), and indeterminate in 1.3%. The monophasic pattern showed lower insulin-sensitivity and worse beta-cell function. Patients with a biphasic pattern had a higher BMI, waist circumference, and blood pressure, although the results were not significant. Latin-American patients had significantly lower serum glucose levels with higher insulin levels during the OGTT. The pattern of response to an OGTT reflects different metabolic phenotypes. Paediatric patients with a biphasic pattern have lower risk-profiling for T2D. The performing of an OGTT could be useful to implement early intervention strategies in children and adolescents with obesity, in order to prevent the development of pre-diabetes or T2D. Copyright © 2016 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Systematic study on the influence of the morphology of α-MoO{sub 3} in the selective oxidation of propylene

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

Schuh, Kirsten; Kleist, Wolfgang; Høj, Martin

2015-08-15

A variety of morphologically different α-MoO{sub 3} samples were prepared by hydrothermal synthesis and applied in the selective oxidation of propylene. Their catalytic performance was compared to α-MoO{sub 3} prepared by flame spray pyrolysis (FSP) and a classical synthesis route. Hydrothermal synthesis from ammonium heptamolybdate (AHM) and nitric acid at pH 1–2 led to ammonium containing molybdenum oxide phases that were completely transformed into α-MoO{sub 3} after calcination at 550 °C. A one-step synthesis of α-MoO{sub 3} rods was possible starting from MoO{sub 3}·2H{sub 2}O with acetic acid or nitric acid and from AHM with nitric acid at 180 °C.more » Particularly, if nitric acid was used during synthesis, the rod-like morphology of the samples could be stabilized during calcination at 550 °C and the following catalytic activity tests, which was beneficial for the catalytic performance in propylene oxidation. Characterization studies using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy showed that those samples, which retained their rod-like morphology during the activity tests, yielded the highest propylene conversion. - Graphical abstract: Hydrothermal synthesis from MoO{sub 3}·2H{sub 2}O in the presence of HNO{sub 3} led to rod-shaped particles which mainly expose (1 0 0) facets which are the most active surfaces. - Highlights: • Hydrothermal synthesis of MoO3 resulted in either rod or slab shaped particles depending on pH. • At pH<0 rods stable towards calcination and catalytic activity testing were formed. • Rod shaped particles had significantly higher activity than slab shaped ones. • The rod shaped particles mainly expose the (1 0 0) facets which are the most active surfaces. • Total surface area is not main determining factor for catalytic activity.« less

Two-year performance study of porous, thermoset, shape memory polyurethanes intended for vascular medical devices

NASA Astrophysics Data System (ADS)

Weems, Andrew C.; Boyle, Anthony J.; Maitland, Duncan J.

2017-03-01

The long-term shape-recovery behavior of shape memory polymers has often been shown to be dependent on the length of time the material has been stored in the secondary shape. Typically, recovery performance and shape fixity will decrease with increased time in the secondary shape. In medical materials, a shelf-life is crucial to establish as it sets the upper threshold for device performance in a clinical setting, and a reduction in shape recovery would limit the development of SMP medical devices. Here, we present a two-year study of strain recovery, strain fixity, and shape recovery kinetics for passively and actively actuated SMPs intended for vascular devices. While kinetic experiments using immersion DMA indicate slight material relaxation and a decrease in the time to recovery, these changes are not found for bulk recovery experiments. The results indicate that a two-year shelf-life for these SMPs is very reasonable, as there is no change in the recovery kinetics, strain recovery, or strain fixity associated with this aging time. Further, a thermal accelerated aging test is presented for more rapid testing of the shape memory behavior of these SMPs and is compared with the real time aging results, indicating that this test is a reasonable indicator of the two-year behavior.

Effect of panel shape on hydrodynamic performances of vertical v-shaped double- slotted cambered otter-board

NASA Astrophysics Data System (ADS)

Wang, Lei; Zhang, Xun; Wang, Lu Min; Huang, Hong Liang; Zhang, Yu; Liu, Yong Li; Feng, Wei Dong; Zhang, Rong Jun

2018-06-01

The effect of panel shape on hydrodynamic performances of a vertical v-shaped double-slotted cambered otter-board was investigated using engineering models in a wind tunnel. Three different shape panels (rhomboid, left trapezoid and isosceles trapezoid) were evaluated at a wind speed of 28 m/s. Parameters measured included: drag coefficient Cx, lift coefficient Cy, pitch moment coefficient Cm, center of pressure coefficient Cp , over a range of angle of attack (0° to 70°). These coefficients were used in analyzing the differences in the performance among the three otter-board models. Results showed that the maximum lift coefficient Cy of the otter-board model with the isosceles trapezoid shape panels was highest (2.103 at α=45°). The maximum Cy/Cx of the otter-board with the rhomboid shape panels was highest (3.976 at α=15°). A comparative analysis of Cm and Cp showed that the stability of otter-board model with the isosceles trapezoid shape panels is better in pitch, and the stability of otter-board model with the left trapezoid shape panels is better in roll. The findings of this study can offer useful reference data for the structural optimization of otter-boards for trawling.

Simians in the Shape School: A comparative study of executive attention.

PubMed

French, Kristin; Beran, Michael J; Espy, Kimberly Andrews; Washburn, David A

2018-01-08

Executive functions (EF) have been studied extensively in children and adults. However, EF tasks for young children can be difficult to administer and interpret. Espy (1997, Developmental Neuropsychology, 13, 495-499) designed the Shape School task to measure inhibition and switching in preschool-aged children. Shape School presents cartoon-like characters that children must flexibly name by their color, their shape, or both, depending on cues that indicate the appropriate rule. Shape School has been found to be age sensitive as well as predictive of performance on other EF tasks. We presented a computerized analogue of Shape School to seven rhesus macaques. Monkeys were trained to categorize characters by color or shape, or to inhibit this response, depending on whether the characters had eyes open, eyes closed, or wore hats. Monkeys performed above chance on the inhibition and switching components of the task. Long runs of a single classification rule and long runs of noninhibition trials had no significant impact on performance when the rule changed or inhibition was required. This nonverbal adaptation of Shape School can measure EF in nonhuman animals and could be used in conjunction with other EF tasks to provide a clearer picture of both human and nonhuman executive functions.

Stereotactic core needle breast biopsy marker migration: An analysis of factors contributing to immediate marker migration.

PubMed

Jain, Ashali; Khalid, Maria; Qureshi, Muhammad M; Georgian-Smith, Dianne; Kaplan, Jonah A; Buch, Karen; Grinstaff, Mark W; Hirsch, Ariel E; Hines, Neely L; Anderson, Stephan W; Gallagher, Katherine M; Bates, David D B; Bloch, B Nicolas

2017-11-01

To evaluate breast biopsy marker migration in stereotactic core needle biopsy procedures and identify contributing factors. This retrospective study analyzed 268 stereotactic biopsy markers placed in 263 consecutive patients undergoing stereotactic biopsies using 9G vacuum-assisted devices from August 2010-July 2013. Mammograms were reviewed and factors contributing to marker migration were evaluated. Basic descriptive statistics were calculated and comparisons were performed based on radiographically-confirmed marker migration. Of the 268 placed stereotactic biopsy markers, 35 (13.1%) migrated ≥1 cm from their biopsy cavity. Range: 1-6 cm; mean (± SD): 2.35 ± 1.22 cm. Of the 35 migrated biopsy markers, 9 (25.7%) migrated ≥3.5 cm. Patient age, biopsy pathology, number of cores, and left versus right breast were not associated with migration status (P> 0.10). Global fatty breast density (P= 0.025) and biopsy in the inner region of breast (P = 0.031) were associated with marker migration. Superior biopsy approach (P= 0.025), locally heterogeneous breast density, and t-shaped biopsy markers (P= 0.035) were significant for no marker migration. Multiple factors were found to influence marker migration. An overall migration rate of 13% supports endeavors of research groups actively developing new biopsy marker designs for improved resistance to migration. • Breast biopsy marker migration is documented in 13% of 268 procedures. • Marker migration is affected by physical, biological, and pathological factors. • Breast density, marker shape, needle approach etc. affect migration. • Study demonstrates marker migration prevalence; marker design improvements are needed.

Cyclic adenosine monophosphate levels and the function of skin microvascular endothelial cells.

PubMed

Tuder, R M; Karasek, M A; Bensch, K G

1990-02-01

The maintenance of the normal epithelioid morphology of human dermal microvascular endothelial cells (MEC) grown in vitro depends strongly on the presence of factors that increase intracellular levels of cyclic AMP. Complete removal of dibutyryl cAMP and isobutylmethylxanthine (IMX) from the growth medium results in a progressive transition from an epithelioid to a spindle-shaped cell line. This transition cannot be reversed by the readdition of dibutyryl cAMP and IMX to the growth medium or by addition of agonists that increase cAMP levels. Spindle-shaped MEC lose the ability to express Factor VIII rAG and DR antigens and to bind peripheral blood mononuclear leukocyte (PBML). Ultrastructural analyses of transitional cells and spindle-shaped cells show decreased numbers of Weibel-Palade bodies in transitional cells and their complete absence in spindle-shaped cells. Interferon-gamma alters several functional properties of both epithelioid and spindle-shaped cells. In the absence of dibutyryl cAMP it accelerates the transition from epithelial to spindle-shaped cells, whereas in the presence of cyclic AMP interferon-gamma increases the binding of PBMLs to both epithelioid and spindle-shaped MEC and the endocytic activity of the endothelial cells. These results suggest that cyclic AMP is an important second messenger in the maintenance of several key functions of microvascular endothelial cells. Factors that influence the levels of this messenger in vivo can be expected to influence the angiogenic and immunologic functions of the microvasculature.

Radiographic Measurements of the Affected and Unaffected Feet in Patients with Unilateral Hallux Limitus A Case-Control Pilot Study.

PubMed

Knox, Andrew F; Bryant, Alan R

2016-05-01

Controversy exists regarding the structural and functional causes of hallux limitus, including metatarsus primus elevatus, a long first metatarsal, first-ray hypermobility, the shape of the first metatarsal head, and the presence of hallux interphalangeus. Some articles have reported on the radiographic evaluation of these measurements in feet affected by hallux limitus, but no study has directly compared the affected and unaffected feet in patients with unilateral hallux limitus. This case-control pilot study aimed to establish whether any such differences exist. Dorsoplantar and lateral weightbearing radiographs of both feet in 30 patients with unilateral hallux limitus were assessed for grade of disease, lateral intermetatarsal angle, metatarsal protrusion distance, plantar gapping at the first metatarsocuneiform joint, metatarsal head shape, and hallux abductus interphalangeus angle. Data analysis was performed using a statistical software program. Mean radiographic measurements for affected and unaffected feet demonstrated that metatarsus primus elevatus, a short first metatarsal, first-ray hypermobility, a flat metatarsal head shape, and hallux interphalangeus were prevalent in both feet. There was no statistically significant difference between feet for any of the radiographic parameters measured (Mann-Whitney U tests, independent-samples t tests, and Pearson χ(2) tests: P > .05). No significant differences exist in the presence of the structural risk factors examined between affected and unaffected feet in patients with unilateral hallux limitus. The influence of other intrinsic factors, including footedness and family history, should be investigated further.

Discordant genetic diversity and geographic patterns between Crassicutis cichlasomae (Digenea: Apocreadiidae) and its cichlid host, "Cichlasoma" urophthalmus (Osteichthyes: Cichlidae), in Middle-America.

PubMed

Razo-Mendivil, Ulises; Vázquez-Domínguez, Ella; de León, Gerardo Pérez-Ponce

2013-12-01

Genetic analyses of hosts and their parasites are key to understand the evolutionary patterns and processes that have shaped host-parasite associations. We evaluated the genetic structure of the digenean Crassicutis cichlasomae and its most common host, the Mayan cichlid "Cichlasoma" urophthalmus, encompassing most of their geographical range in Middle-America (river basins in southeastern Mexico, Belize, and Guatemala together with the Yucatan Peninsula). Genetic diversity and structure analyses were done based on 167 cytochrome c oxidase subunit 1 sequences (330 bp) for C. cichlasomae from 21 populations and 161 cytochrome b sequences (599 bp) for "C." urophthalmus from 26 populations. Analyses performed included phylogenetic tree estimation under Bayesian inference and maximum likelihood analysis, genetic diversity, distance and structure estimates, haplotype networks, and demographic evaluations. Crassicutis cichlasomae showed high genetic diversity values and genetic structuring, corresponding with 4 groups clearly differentiated and highly divergent. Conversely, "C." urophthalmus showed low levels of genetic diversity and genetic differentiation, defined as 2 groups with low divergence and with no correspondence with geographical distribution. Our results show that species of cichlids parasitized by C. cichlasomae other than "C." urophthalmus, along with multiple colonization events and subsequent isolation in different basins, are likely factors that shaped the genetic structure of the parasite. Meanwhile, historical long-distance dispersal and drought periods during the Holocene, with significant population size reductions and fragmentations, are factors that could have shaped the genetic structure of the Mayan cichlid.

Large-scale distribution patterns of mangrove nematodes: A global meta-analysis.

PubMed

Brustolin, Marco C; Nagelkerken, Ivan; Fonseca, Gustavo

2018-05-01

Mangroves harbor diverse invertebrate communities, suggesting that macroecological distribution patterns of habitat-forming foundation species drive the associated faunal distribution. Whether these are driven by mangrove biogeography is still ambiguous. For small-bodied taxa, local factors and landscape metrics might be as important as macroecology. We performed a meta-analysis to address the following questions: (1) can richness of mangrove trees explain macroecological patterns of nematode richness? and (2) do local landscape attributes have equal or higher importance than biogeography in structuring nematode richness? Mangrove areas of Caribbean-Southwest Atlantic, Western Indian, Central Indo-Pacific, and Southwest Pacific biogeographic regions. We used random-effects meta-analyses based on natural logarithm of the response ratio (lnRR) to assess the importance of macroecology (i.e., biogeographic regions, latitude, longitude), local factors (i.e., aboveground mangrove biomass and tree richness), and landscape metrics (forest area and shape) in structuring nematode richness from 34 mangroves sites around the world. Latitude, mangrove forest area, and forest shape index explained 19% of the heterogeneity across studies. Richness was higher at low latitudes, closer to the equator. At local scales, richness increased slightly with landscape complexity and decreased with forest shape index. Our results contrast with biogeographic diversity patterns of mangrove-associated taxa. Global-scale nematode diversity may have evolved independently of mangrove tree richness, and diversity of small-bodied metazoans is probably more closely driven by latitude and associated climates, rather than local, landscape, or global biogeographic patterns.

Analysis of the shapes of hemocytes of Callista brevisiphonata in vitro (Bivalvia, Veneridae).

PubMed

Karetin, Yu A; Pushchin, I I

2015-08-01

Fractal formalism in conjunction with linear methods of image analysis is suitable for the comparative analysis of such "irregular" shapes (from the point of view of classical Euclidean geometry) as flattened amoeboid cells of invertebrates in vitro. Cell morphology of in vitro spreading hemocytes from the bivalve mollusc Callista brevisiphonata was analyzed using correlation, factor and cluster analysis. Four significantly different cell types were identified on the basis of 36 linear and nonlinear parameters. The analysis confirmed the adequacy of the selected methodology for numerical description of the shape and the adequacy of classification of nonlinear shapes of spread hemocytes belonging to the same species. Investigation has practical significance for the description of the morphology of cultured cells, since cell shape is a result of summation of a number of extracellular and intracellular factors. © 2015 International Society for Advancement of Cytometry.

The role of color in the implicit memory performance of healthy older adults and individuals with Alzheimer's disease.

PubMed

Lloyd-Jones, Toby J

2005-01-01

Although the Alzheimer's disease (AD) patients in this study were severely impaired in recognition performance, their naming performance demonstrated normal priming across transformations in object color. This is evidence for preserved implicit shape-based memory performance in AD patients. For colored-object decision, healthy older adult control participants but not AD patients showed priming for new associations between previously encountered object shapes and colors. The author argues, on the basis of this colored object decision performance, that the deficits present in AD do not allow shape and color to be integrated to form a novel unitized representation that can be used to benefit cognitive performance. 2005 APA

Comparison of geometric morphometric outline methods in the discrimination of age-related differences in feather shape

PubMed Central

Sheets, H David; Covino, Kristen M; Panasiewicz, Joanna M; Morris, Sara R

2006-01-01

Background Geometric morphometric methods of capturing information about curves or outlines of organismal structures may be used in conjunction with canonical variates analysis (CVA) to assign specimens to groups or populations based on their shapes. This methodological paper examines approaches to optimizing the classification of specimens based on their outlines. This study examines the performance of four approaches to the mathematical representation of outlines and two different approaches to curve measurement as applied to a collection of feather outlines. A new approach to the dimension reduction necessary to carry out a CVA on this type of outline data with modest sample sizes is also presented, and its performance is compared to two other approaches to dimension reduction. Results Two semi-landmark-based methods, bending energy alignment and perpendicular projection, are shown to produce roughly equal rates of classification, as do elliptical Fourier methods and the extended eigenshape method of outline measurement. Rates of classification were not highly dependent on the number of points used to represent a curve or the manner in which those points were acquired. The new approach to dimensionality reduction, which utilizes a variable number of principal component (PC) axes, produced higher cross-validation assignment rates than either the standard approach of using a fixed number of PC axes or a partial least squares method. Conclusion Classification of specimens based on feather shape was not highly dependent of the details of the method used to capture shape information. The choice of dimensionality reduction approach was more of a factor, and the cross validation rate of assignment may be optimized using the variable number of PC axes method presented herein. PMID:16978414

The Use of Empirical Data Sources in HRA

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

Bruce Hallbert; David Gertman; Julie Marble

This paper presents a review of available information related to human performance to support Human Reliability Analysis (HRA) performed for nuclear power plants (NPPs). A number of data sources are identified as potentially useful. These include NPP licensee event reports (LERs), augmented inspection team (AIT) reports, operator requalification data, results from the literature in experimental psychology, and the Aviation Safety Reporting System (ASRSs). The paper discusses how utilizing such information improves our capability to model and quantify human performance. In particular the paper discusses how information related to performance shaping factors (PSFs) can be extracted from empirical data to determinemore » their size effect, their relative effects, as well as their interactions. The paper concludes that appropriate use of existing sources can help addressing some of the important issues we are currently facing in HRA.« less

Walking the talk: how effective boards accelerate performance. Interview by Elizabeth Preiss, Ron Shulman, and Patrick O'Callaghan.

PubMed

Bisson, A; Blais, B; Cullen, M; Gagné-Koch, G; Hassen, P C; Hearn, A; Tegenfeldt, J H

1993-01-01

The interviews demonstrated the belief that boards are accountable for ensuring the effective performance of their organizations. A board's obligation and authority is not limited to recruiting, appointing and replacing the organization's CEO and officers. It must also guide, shape, improve and reward what people do on the job. Performance management is not a simple process. It depends on a number of contributing factors operating in concert. To perform well, people must understand what is expected of them, their work context and their role. They must receive appropriate feedback on how they are doing from someone whom they respect and trust, someone with insight into their jobs and authority to manage them. The board's ability and obligation to contribute leadership, to be the primary force steering the organization, rests on the effectiveness with which it is able to play the performance management role.

Habitat Utilization Assessment - Building in Behaviors

NASA Technical Reports Server (NTRS)

Whitmore, Mihriban; Blume, Jennifer

2004-01-01

Habitability, and the associated architectural and design attributes of an environment, is a powerful performance shaping factor. By identifying how inhabitants use an area, we can draw conclusions about what design or architectural attributes cause what behaviors and systematically design in desired human performance. We are analyzing how a crew uses a long duration habitat and work environment during a four-day underwater mission and identifying certain architectural and design attributes that are related to, and potential enablers of, certain crew behaviors. By identifying how inhabitants use the habitat, we can draw conclusions about what habitability attributes cause what behaviors and systematically design in desired human performance (applicable to NASA's Bioastronautics Human Behavior and Performance Critical Path Roadmap question 6.12). This assessment replicates a methodology reported in a chapter titled "Sociokinetic Analysis as a Tool for Optimization of Environmental Design" by C. Adams.' That study collected video imagery of certain areas of a closed habitat during a 91 day test and from that data calculated time spent in different volumes during the mission, and characterized the behaviors occurring in certain habitat volumes thus concluding various rules for design of such habitats. This study assesses the utilization of the Aquarius Habitat, an underwater station, which will support six Aquanauts for a fourteen-day mission during which the crew will perform specific scientific and engineering studies. Video is recorded for long uninterrupted periods of time during the mission and from that data the time spent in each area is calculated. In addition, qualitative and descriptive analysis of the types of behaviors in each area is performed with the purpose of identifying any behaviors that are not typical of a certain area. If a participant uses an area in a way different from expected, a subsequent analysis of the features of that area may result in conclusions of performance shaping factors. With the addition of this study, we can make comparisons between the two different habitats and begin drawing correlation judgments about design features and behavior. Ideally, this methodology should be repeated in additional Aquarius missions and other analog environments because the real information will come from comparisons between habitats.

Young onset dementia: the impact of emergent age-based factors upon personhood.

PubMed

Tolhurst, Edward; Bhattacharyya, Sarmishtha; Kingston, Paul

2014-03-01

This paper evaluates how emergent age-based factors may impact upon the experience of dementia. A review of selected literature is undertaken to explore how personhood has been conceptualised in relation to dementia. It is then highlighted that very little literature explicitly addresses personhood with reference to young onset dementia. Young onset dementia is defined, and evaluation is then undertaken of the distinctive age-based factors that might shape the experience of the condition. It is noted that whilst there are separate literatures on both personhood and young onset dementia, there appears to be little endeavour to draw these two strands of thought together. The distinctive factors that shape young onset dementia suggest that a more heterogeneous perspective should be developed that accounts more appropriately for how personal characteristics shape the lived experience of dementia. The paper concludes that further research should be undertaken that has an explicit focus on personhood and young onset dementia.

Damping of High-temperature Shape Memory Alloys

NASA Technical Reports Server (NTRS)

Duffy, Kirsten P.; Padula, Santo A., II; Scheiman, Daniel A.

2008-01-01

Researchers at NASA Glenn Research Center have been investigating high temperature shape memory alloys as potential damping materials for turbomachinery rotor blades. Analysis shows that a thin layer of SMA with a loss factor of 0.04 or more would be effective at reducing the resonant response of a titanium alloy beam. Two NiTiHf shape memory alloy compositions were tested to determine their loss factors at frequencies from 0.1 to 100 Hz, at temperatures from room temperature to 300 C, and at alternating strain levels of 34-35x10(exp -6). Elevated damping was demonstrated between the M(sub s) and M(sub f) phase transformation temperatures and between the A(sub s) and A(sub f) temperatures. The highest damping occurred at the lowest frequencies, with a loss factor of 0.2-0.26 at 0.1 Hz. However, the peak damping decreased with increasing frequency, and showed significant temperature hysteresis in heating and cooling. Keywords: High-temperature, shape memory alloy, damping, aircraft engine blades, NiTiHf

The performance of discrete models of low Reynolds number swimmers.

PubMed

Wang, Qixuan; Othmer, Hans G

2015-12-01

Swimming by shape changes at low Reynolds number is widely used in biology and understanding how the performance of movement depends on the geometric pattern of shape changes is important to understand swimming of microorganisms and in designing low Reynolds number swimming models. The simplest models of shape changes are those that comprise a series of linked spheres that can change their separation and/or their size. Herein we compare the performance of three models in which these modes are used in different ways.

Gliding locomotion of manta rays, killer whales and swordfish near the water surface.

PubMed

Zhan, Jie-Min; Gong, Ye-Jun; Li, Tian-Zeng

2017-03-24

The hydrodynamic performance of the locomotive near the water surface is impacted by its geometrical shape. For marine animals, their geometrical shape is naturally selective; thus, investigating gliding locomotion of marine animal under the water surface may be able to elucidate the influence of the geometrical shape. We investigate three marine animals with specific geometries: the killer whale is fusiform shaped; the manta ray is flat and broad-winged; and the swordfish is best streamlined. The numerical results are validated by the measured drag coefficients of the manta ray model in a towing tank. The friction drag of the three target models are very similar; the body shape affected form drag coefficient is order as swordfish < killer whale < manta ray; the induced wave breaking upon the body of the manta ray performs different to killer whale and swordfish. These bio-inspired observations provide a new and in-depth understanding of the shape effects on the hydrodynamic performances near the free surface.

Optimization of Robotic Spray Painting process Parameters using Taguchi Method

NASA Astrophysics Data System (ADS)

Chidhambara, K. V.; Latha Shankar, B.; Vijaykumar

2018-02-01

Automated spray painting process is gaining interest in industry and research recently due to extensive application of spray painting in automobile industries. Automating spray painting process has advantages of improved quality, productivity, reduced labor, clean environment and particularly cost effectiveness. This study investigates the performance characteristics of an industrial robot Fanuc 250ib for an automated painting process using statistical tool Taguchi’s Design of Experiment technique. The experiment is designed using Taguchi’s L25 orthogonal array by considering three factors and five levels for each factor. The objective of this work is to explore the major control parameters and to optimize the same for the improved quality of the paint coating measured in terms of Dry Film thickness(DFT), which also results in reduced rejection. Further Analysis of Variance (ANOVA) is performed to know the influence of individual factors on DFT. It is observed that shaping air and paint flow are the most influencing parameters. Multiple regression model is formulated for estimating predicted values of DFT. Confirmation test is then conducted and comparison results show that error is within acceptable level.

Vehicle integration effects on hypersonic waveriders. M.S. Thesis - George Washington Univ.

NASA Technical Reports Server (NTRS)

Cockrell, Charles Edward, Jr.

1994-01-01

The integration of a class of hypersonic high-lift configurations known as waveriders into hypersonic cruise vehicles was evaluated. Waveriders offer advantages in aerodynamic performance and propulsion/airframe integration (PAI) characteristics over conventional hypersonic shapes. A wind-tunnel model was developed which integrates realistic vehicle components with two waverider shapes, referred to as the 'straight-wing' and 'cranked-wing' shapes. Both shapes were conical-flow-derived waveriders at a design Mach number of 4.0. The cranked-wing shape was designed to provide advantages in subsonic performance and directional stability over conventional waveriders. Experimental data and limited computational fluid dynamics (CFD) predictions were obtained over a Mach number range of 2.3 to 4.63 at a Reynolds number of 2.0x10(exp 6) per foot. The CFD predictions and flow visualization data confirmed the shock attachment characteristics of the baseline waverider shapes and illustrated the waverider flow-field properties. Both CFD predictions and experimental data showed that no significant performance degradations occur at off-design Mach numbers for the waverider shapes and the integrated configurations. The experimental data showed that the effects of adding a realistic canopy were minimal. The effects of adding engine components were to increase the drag and thus degrade the aerodynamic performance of the configuration. A significant degradation in aerodynamic performance was observed when 0 degree control surfaces were added to close the blunt base of the waverider to a sharp trailing edge. A comparison of the fully-integrated waverider models to the baseline shapes showed that the performance was significantly degraded when all of the components were added to the waveriders. The fully-integrated configurations studied here do not offer significant performance advantages over conventional hypersonic vehicles, but still offer advantages in air-breathing propulsion integration. Additionally, areas are identified in this study where improvements could be made to enhance the performance. Both fully-integrated configurations are longitudinally unstable over the Mach number range studied for unpowered conditions. The cranked-wing fully-integrated configuration provided significantly better lateral-directional stability characteristics than the straight-wing configuration.

Effects of Pump-turbine S-shaped Characteristics on Transient Behaviours: Experimental Investigation

NASA Astrophysics Data System (ADS)

Zeng, Wei; Yang, Jiandong; Hu, Jinhong; Tang, Renbo

2017-05-01

A pumped storage stations model was set up and introduced in the previous paper. In the model station, the S-shaped characteristic curves was measured at the load rejection condition with the guide vanes stalling. Load rejection tests where guide-vane closed linearly were performed to validate the effect of the S-shaped characteristics on hydraulic transients. Load rejection experiments with different guide vane closing schemes were also performed to determine a suitable scheme considering the S-shaped characteristics. The condition of one pump turbine rejecting its load after another defined as one-after-another (OAA) load rejection was performed to validate the possibility of S-induced extreme draft tube pressure.

Qualitative skeletal correlates of wing shape in extant birds (Aves: Neoaves).

PubMed

Hieronymus, Tobin L

2015-02-27

Among living fliers (birds, bats, and insects), birds display relatively high aspect ratios, a dimensionless shape variable that distinguishes long and narrow vs. short and broad wings. Increasing aspect ratio results in a functional tradeoff between low induced drag (efficient cruise) and increased wing inertia (difficult takeoff). Given the wide scope of its functional effects, the pattern of aspect ratio evolution is an important factor that contributes to the substantial ecological and phylogenetic diversity of living birds. However, because the feathers that define the wingtip (and hence wingspan and aspect ratio) often do not fossilize, resolution in the pattern of avian wing shape evolution is obscured by missing information. Here I use a comparative approach to investigate the relationship between skeletal proxies of flight feather attachment and wing shape. An accessory lobe of the internal index process of digit II-1, a bony correlate of distal primary attachment, shows weak but statistically significant relationships to aspect ratio and mass independent of other skeletal morphology. The dorsal phalangeal fossae of digit II-1, which house distal primaries VIII and IX, also show a trend of increased prominence with higher aspect ratio. Quill knobs on the ulna are examined concurrently, but do not show consistent signal with respect to wing shape. Although quill knobs are cited as skeletal correlates of flight performance in birds, their relationship to wing shape is inconsistent among extant taxa, and may reflect diverging selection pressures acting on a conserved architecture. In contrast, correlates of distal primary feather attachment on the major digit show convergent responses to increasing aspect ratio. In light of the diversity of musculoskeletal and integumentary mophology that underlies wing shape in different avian clades, it is unlikely that a single skeletal feature will show consistent predictive power across Neoaves. Confident inference of wing shape in basal ornithurine birds will require multiple lines of evidence, together with an understanding of clade-specific evolutionary trends within the crown.

Karyotyping human chromosomes by optical and x-ray ptychography methods

DOE PAGES

Shemilt, Laura; Verbanis, Ephanielle; Schwenke, Joerg; ...

2015-02-01

Sorting and identifying chromosomes, a process known as karyotyping, is widely used to detect changes in chromosome shapes and gene positions. In a karyotype the chromosomes are identified by their size and therefore this process can be performed by measuring macroscopic structural variables. Chromosomes contain a specific number of basepairs that linearly correlate with their size; therefore, it is possible to perform a karyotype on chromosomes using their mass as an identifying factor. Here, we obtain the first images, to our knowledge, of chromosomes using the novel imaging method of ptychography. We can use the images to measure the massmore » of chromosomes and perform a partial karyotype from the results. Lastly, we also obtain high spatial resolution using this technique with synchrotron source x-rays.« less

Karyotyping human chromosomes by optical and x-ray ptychography methods

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

Shemilt, Laura; Verbanis, Ephanielle; Schwenke, Joerg

Sorting and identifying chromosomes, a process known as karyotyping, is widely used to detect changes in chromosome shapes and gene positions. In a karyotype the chromosomes are identified by their size and therefore this process can be performed by measuring macroscopic structural variables. Chromosomes contain a specific number of basepairs that linearly correlate with their size; therefore, it is possible to perform a karyotype on chromosomes using their mass as an identifying factor. Here, we obtain the first images, to our knowledge, of chromosomes using the novel imaging method of ptychography. We can use the images to measure the massmore » of chromosomes and perform a partial karyotype from the results. Lastly, we also obtain high spatial resolution using this technique with synchrotron source x-rays.« less

Controlled crack shapes for indentation fracture of soda-lime glass

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

Smith, S.M.; Scattergood, R.O.

1992-01-01

Radial cracks for indented soda-lime glass aged in distilled water were highly elliptical because of truncation by lateral cracks. Indentation in silicone oil minimized radial/lateral crack interaction but still produced cracks having nominally constant ellipticity during bend testing. Analysis of applied stress/indentation crack length data using stress intensity factors based on half-penny crack shape resulted in apparent R-curve behavior and/or overestimation of the fracture toughness. Incorporation of elliptical shape factors eliminated the R-curve behavior and reduced measured toughness to near the accepted value for soda-lime glass.

An observational study investigating the association of ultrasonographically assessed machine milking-induced changes in teat condition and teat-end shape in dairy cows.

PubMed

Wieland, M; Virkler, P D; Borkowski, A H; Älveby, N; Wood, P; Nydam, D V

2018-06-21

Mechanical forces during machine milking induce changes in teat condition which can be differentiated into short-term and long-term changes. Machine milking-induced short-term changes in teat condition (STC) are defined as tissue responses to a single milking and have been associated with the risk of new intramammary infection. Albeit, their association with teat characteristics, such as teat-end shape, has not been investigated by rigorous methods. The primary objective was to determine the association of STC, as measured by ultrasonography, with teat-end shape. The second objective was to describe possible differences in the recovery time of teat tissue after machine milking among teats with different teat-end shapes. Holstein cows (n=128) were enrolled in an observational study, housed in free-stall pens with sand bedding and milked three times a day. Ultrasonography of the left front and right hind teat was performed after teat preparation before milking (t-1), immediately after milking (t 0) and 1, 3, 5 and 7 h after milking (t 1, t 3, t 5, t 7). The teat tissue parameters measured from ultrasound scans were teat canal length, teat-end diameter, teat-end diameter at the midpoint between the distal and proximal end of the teat canal, teat wall thickness, and teat cistern width. Teat-end shape was assessed visually and classified into three categories: pointed, flat and round. Multivariable linear regression analyses showed differences in the relative change of teat tissue parameters (compared with t-1) at t 0 among teats with different teat-end shapes, with most parameters showing the largest change for round teats. The premilking values were reached (recovery time) after 7 h in teats with a pointed teat-end shape, whereas recovery time was greater than 7 h in teats with flat and round teat-end shapes. Under the same liner and milking machine conditions, teats with a round teat-end shape had the most severe short-term changes. The results of this observational study indicated that teat-end shape may be one of the factors that contribute to the severity of STC.

The location of “8”-shaped hatching influences inner cell mass formation in mouse blastocysts

PubMed Central

Takahashi, Kazumasa; Goto, Mayumi; Anzai, Mibuki; Ono, Natsuki; Shirasawa, Hiromitsu; Sato, Wataru; Miura, Hiroshi; Sato, Naoki; Sato, Akira; Kumazawa, Yukiyo; Terada, Yukihiro

2017-01-01

The hatching of a blastocyst where the blastocyst portions on the inside and the outside of the zona pellucida feature a figure-of-eight shape is termed “8”-shaped hatching; this type of hatching has been reported to affect the proper presentation of the inner cell mass (ICM) in both human and mouse embryos. Here, our aim was to investigate the factors that affect ICM presentation during “8”-shaped hatching. We performed IVF by using B6D2F1 female mice and ICR male mice, and used the 104 captured blastocysts. Embryos were maintained in KSOM at 37°C in a 5% CO2, 5% O2, and 90% N2 environment, and their growth behavior was monitored individually and continuously using time-lapse cinematography. At 120 h after insemination, embryos were immunostained and examined under a confocal microscope. We used the hatching form to identify “8”-shaped hatching, and we classified the “8”-shaped-hatching blastocysts into two groups, one in which the hatching site was near the ICM center, and the other in which the hatching site was far from the ICM center. We measured each group for ICM size and the number of Oct3/4-positive cells. Of the 95 hatching or hatched embryos, 74 were “8”-shaped-hatching blastocysts, and in these embryos, the ICM was significantly wider when the hatching site was near the ICM than when the hatching site was far from the ICM (P = 0.0091). Moreover, in the “8”-shaped-hatching blastocysts in which the ICM was included in the blastocyst portion outside the zona pellucida―the portion defined as the “outside blastocyst”―after the collapse of this outside blastocyst, the ICM adhered to the trophectoderm of the outside blastocyst, opposite the hatching site. Our results indicate that in “8”-shaped-hatching blastocysts, the hatching site and the collapse of outside blastocyst affect ICM formation. Thus, the assessment of “8”-shaped hatching behaviors could yield indices for accurately evaluating embryo quality. PMID:28384351

Optimization of the photoneutron target geometry for e-accelerator based BNCT.

PubMed

Chegeni, Nahid; Pur, Saleh Boveiry; Razmjoo, Sasan; Hoseini, Seydeh Khadijed

2017-06-01

Today, electron accelerators are taken into consideration as photoneutron sources. Therefore, for maximum production of epithermal neutron flux, designing a photoneutron target is of significant importance. In this paper, the effect of thickness and geometric shape of a photoneutron target on neutron output were investigated. In this study, a pencil photon source with 13, 15, 18, 20 and 25 MeV energies and a diameter of 2 mm was investigated using Monte Carlo simulation method using MCNP code. To optimize the design of the photoneutron target, the tungsten target with various geometries and thicknesses was investigated. The maximum neutron flux produced for all target geometries and thicknesses occurred at neutron energy peak of around 0.46 MeV. As the thickness increased to 2 cm, neutron flux increased and then a decreasing trend was observed. For various geometrical shapes, the determining factor in photoneutron output was the effective target thickness in the photon interaction path that increased by the increase in the area of interaction. Another factor was the angle of the photon's incidence with the target surface that resulted in a significant decrease in photoneutron output in cone-shaped targets. Three factors including the total neutron flux, neutrons energy spectrum, and convergence of neutrons plays an important role in the selection of geometry and shape of the target that should be investigated considering beam shaping assembly (BSA) shape.

Broadband optical frequency comb generator based on driving N-cascaded modulators by Gaussian-shaped waveform

NASA Astrophysics Data System (ADS)

Hmood, Jassim K.; Harun, Sulaiman W.

2018-05-01

A new approach for realizing a wideband optical frequency comb (OFC) generator based on driving cascaded modulators by a Gaussian-shaped waveform, is proposed and numerically demonstrated. The setup includes N-cascaded MZMs, a single Gaussian-shaped waveform generator, and N-1 electrical time delayer. The first MZM is driven directly by a Gaussian-shaped waveform, while delayed replicas of the Gaussian-shaped waveform drive the other MZMs. An analytical model that describes the proposed OFC generator is provided to study the effect of number and chirp factor of cascaded MZM as well as pulse width on output spectrum. Optical frequency combs at frequency spacing of 1 GHz are generated by applying Gaussian-shaped waveform at pulse widths ranging from 200 to 400 ps. Our results reveal that, the number of comb lines is inversely proportional to the pulse width and directly proportional to both number and chirp factor of cascaded MZMs. At pulse width of 200 ps and chirp factor of 4, 67 frequency lines can be measured at output spectrum of two-cascaded MZMs setup. Whereas, increasing the number of cascaded stages to 3, 4, and 5, the optical spectra counts 89, 109 and 123 frequency lines; respectively. When the delay time is optimized, 61 comb lines can be achieved with power fluctuations of less than 1 dB for five-cascaded MZMs setup.

Scale factor management in the studies of affine models of shockproof garment elements

NASA Astrophysics Data System (ADS)

Denisov, Oleg; Pleshko, Mikhail; Ponomareva, Irina; Merenyashev, Vitaliy

2018-03-01

New samples of protective garment for performing construction work at height require numerous tests in conditions close to real conditions of extreme vital activity. The article presents some results of shockproof garment element studies and a description of a patented prototype. The tests were carried out on a model which geometric dimensions were convenient for manufacturing it in a limited batch. In addition, the used laboratory equipment (for example, a unique power pendulum), blanks made of a titanium-nickel alloy with a shape memory effect also imposed their limitations. The problem of the adequacy of the obtained experimental results transfer to mass-produced products was solved using tools of the classical similarity theory. Scale factor management influence in the affine modeling of the shockproof element, studied on the basis of the equiatomic titanium-nickel alloy with the shape memory effect, allowed us to assume, with a sufficient degree of reliability, the technical possibility of extrapolating the results of experimental studies to full-scale objects for the formation of the initial data of the mathematical model of shockproof garment dynamics elastoplastic deformation (while observing the similarity of the features of external loading).

Robust active contour via additive local and global intensity information based on local entropy

NASA Astrophysics Data System (ADS)

Yuan, Shuai; Monkam, Patrice; Zhang, Feng; Luan, Fangjun; Koomson, Ben Alfred

2018-01-01

Active contour-based image segmentation can be a very challenging task due to many factors such as high intensity inhomogeneity, presence of noise, complex shape, weak boundaries objects, and dependence on the position of the initial contour. We propose a level set-based active contour method to segment complex shape objects from images corrupted by noise and high intensity inhomogeneity. The energy function of the proposed method results from combining the global intensity information and local intensity information with some regularization factors. First, the global intensity term is proposed based on a scheme formulation that considers two intensity values for each region instead of one, which outperforms the well-known Chan-Vese model in delineating the image information. Second, the local intensity term is formulated based on local entropy computed considering the distribution of the image brightness and using the generalized Gaussian distribution as the kernel function. Therefore, it can accurately handle high intensity inhomogeneity and noise. Moreover, our model is not dependent on the position occupied by the initial curve. Finally, extensive experiments using various images have been carried out to illustrate the performance of the proposed method.

Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study

NASA Astrophysics Data System (ADS)

Szarf, Krzysztof; Combe, Gael; Villard, Pascal

2015-02-01

The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete Element Methods. Moreover, Discrete Element approach is able to provide information about the grain-grain and grain-structure interactions at the microscale. This paper presents numerical and experimental investigations of flexible buried pipe behaviour with focus placed on load transfer above the buried structure. Numerical modeling was able to reproduce the experimental results. Load repartition was observed, being affected by a number of factors such as particle shape, pipe friction and pipe stiffness.

Short-wavelength InAlGaAs/AlGaAs quantum dot superluminescent diodes

NASA Astrophysics Data System (ADS)

Liang, De-Chun; An, Qi; Jin, Peng; Li, Xin-Kun; Wei, Heng; Wu, Ju; Wang, Zhan-Guo

2011-10-01

This paper reports the fabrication of J-shaped bent-waveguide superluminescent diodes utilizing an InAlGaAs/AlGaAs quantum dot active region. The emission spectrum of the device is centred at 884 nm with a full width at half maximum of 37 nm and an output power of 18 mW. By incorporating an Al composition into the quantum dot active region, short-wavelength superluminescent diode devices can be obtained. An intersection was found for the light power-injection current curves measured from the straight-waveguide facet and the bent-waveguide facet, respectively. The result is attributed to the conjunct effects of the gain and the additional loss of the bent waveguide. A numerical simulation is performed to verify the qualitative explanation. It is shown that bent waveguide loss is an important factor that affects the output power of J-shaped superluminescent diode devices.

Comparative Population Genomics Analysis of the Mammalian Fungal Pathogen Pneumocystis

PubMed Central

Ma, Liang; Wei Huang, Da; Khil, Pavel P.; Dekker, John P.; Kutty, Geetha; Bishop, Lisa; Liu, Yueqin; Deng, Xilong; Pagni, Marco; Hirsch, Vanessa; Lempicki, Richard A.

2018-01-01

ABSTRACT Pneumocystis species are opportunistic mammalian pathogens that cause severe pneumonia in immunocompromised individuals. These fungi are highly host specific and uncultivable in vitro. Human Pneumocystis infections present major challenges because of a limited therapeutic arsenal and the rise of drug resistance. To investigate the diversity and demographic history of natural populations of Pneumocystis infecting humans, rats, and mice, we performed whole-genome and large-scale multilocus sequencing of infected tissues collected in various geographic locations. Here, we detected reduced levels of recombination and variations in historical demography, which shape the global population structures. We report estimates of evolutionary rates, levels of genetic diversity, and population sizes. Molecular clock estimates indicate that Pneumocystis species diverged before their hosts, while the asynchronous timing of population declines suggests host shifts. Our results have uncovered complex patterns of genetic variation influenced by multiple factors that shaped the adaptation of Pneumocystis populations during their spread across mammals. PMID:29739910

Research on damping properties optimization of variable-stiffness plate

NASA Astrophysics Data System (ADS)

Wen-kai, QI; Xian-tao, YIN; Cheng, SHEN

2016-09-01

This paper investigates damping optimization design of variable-stiffness composite laminated plate, which means fibre paths can be continuously curved and fibre angles are distinct for different regions. First, damping prediction model is developed based on modal dissipative energy principle and verified by comparing with modal testing results. Then, instead of fibre angles, the element stiffness and damping matrixes are translated to be design variables on the basis of novel Discrete Material Optimization (DMO) formulation, thus reducing the computation time greatly. Finally, the modal damping capacity of arbitrary order is optimized using MMA (Method of Moving Asymptotes) method. Meanwhile, mode tracking technique is employed to investigate the variation of modal shape. The convergent performance of interpolation function, first order specific damping capacity (SDC) optimization results and variation of modal shape in different penalty factor are discussed. The results show that the damping properties of the variable-stiffness plate can be increased by 50%-70% after optimization.

What predicts successful literacy acquisition in a second language?

PubMed Central

Frost, Ram; Siegelman, Noam; Narkiss, Alona; Afek, Liron

2013-01-01

We examined whether success (or failure) in assimilating the structure of a second language could be predicted by general statistical learning abilities that are non-linguistic in nature. We employed a visual statistical learning (VSL) task, monitoring our participants’ implicit learning of the transitional probabilities of visual shapes. A pretest revealed that performance in the VSL task is not correlated with abilities related to a general G factor or working memory. We found that native speakers of English who picked up the implicit statistical structure embedded in the continuous stream of shapes, on average, better assimilated the Semitic structure of Hebrew words. Our findings thus suggest that languages and their writing systems are characterized by idiosyncratic correlations of form and meaning, and these are picked up in the process of literacy acquisition, as they are picked up in any other type of learning, for the purpose of making sense of the environment. PMID:23698615

Moderate climate signature in cranial anatomy of late holocene human populations from Southern South America.

PubMed

Paula Menéndez, Lumila

2018-02-01

The aim of this study is to analyze the association between cranial variation and climate in order to discuss their role during the diversification of southern South American populations. Therefore, the specific objectives are: (1) to explore the spatial pattern of cranial variation with regard to the climatic diversity of the region, and (2) to evaluate the differential impact that the climatic factors may have had on the shape and size of the diverse cranial structures studied. The variation in shape and size of 361 crania was studied, registering 62 3D landmarks that capture shape and size variation in the face, cranial vault, and base. Mean, minimum, and maximum annual temperature, as well as mean annual precipitation, but also diet and altitude, were matched for each population sample. A PCA, as well as spatial statistical techniques, including kriging, regression, and multimodel inference were employed. The facial skeleton size presents a latitudinal pattern which is partially associated with temperature diversity. Both diet and altitude are the variables that mainly explain the skull shape variation, although mean annual temperature also plays a role. The association between climate factors and cranial variation is low to moderate, mean annual temperature explains almost 40% of the entire skull, facial skeleton and cranial vault shape variation, while annual precipitation and minimum annual temperature only contribute to the morphological variation when considered together with maximum annual temperature. The cranial base is the structure less associated with climate diversity. These results suggest that climate factors may have had a partial impact on the facial and vault shape, and therefore contributed moderately to the diversification of southern South American populations, while diet and altitude might have had a stronger impact. Therefore, cranial variation at the southern cone has been shaped both by random and nonrandom factors. Particularly, the influence of climate on skull shape has probably been the result of directional selection. This study supports that, although cranial vault is the cranial structure more associated to mean annual temperature, the impact of climate signature on morphology decreases when populations from extreme cold environments are excluded from the analysis. Additionally, it shows that the extent of the geographical scales analyzed, as well as differential sampling may lead to different results regarding the role of ecological factors and evolutionary processes on cranial morphology. © 2017 Wiley Periodicals, Inc.

Scale-model charge-transfer technique for measuring enhancement factors

NASA Technical Reports Server (NTRS)

Kositsky, J.; Nanevicz, J. E.

1991-01-01

Determination of aircraft electric field enhancement factors is crucial when using airborne field mill (ABFM) systems to accurately measure electric fields aloft. SRI used the scale model charge transfer technique to determine enhancement factors of several canonical shapes and a scale model Learjet 36A. The measured values for the canonical shapes agreed with known analytic solutions within about 6 percent. The laboratory determined enhancement factors for the aircraft were compared with those derived from in-flight data gathered by a Learjet 36A outfitted with eight field mills. The values agreed to within experimental error (approx. 15 percent).

Optical properties study of nano-composite filled D shape photonic crystal fibre

NASA Astrophysics Data System (ADS)

Udaiyakumar, R.; Mohamed Junaid, K. A.; Janani, T.; Maheswar, R.; Yupapin, P.; Amiri, I. S.

2018-06-01

With the nano-composite materials gaining momentum in the optical field, a new nano-composite filled D shape Photonic Crystal Fiber (PCF) is designed and the various optical properties are investigated with help of Finite Element Method. In the proposed structure the D-shape PCF is made up of silica with embedded silver nanoparticles and air holes are distributed along the fibre. The designed fibre shows various optical properties such as dispersion, birefringence, beat length and loss with respect to wavelength and compared with different filling factor like 0.1, 0.3 and 0.5. From our estimation and comparative analysis, it has been proved that the fibre loss has been decreased with increasing filling factor. Further this also showed flat dispersion at maximum filling factor.

Axisymmetric elastodynamic response from normal and radial impact of layered composites with embedded penny-shaped cracks

NASA Technical Reports Server (NTRS)

Sih, G. C.; Chen, E. P.

1980-01-01

A method is developed for the dynamic stress analysis of a layered composite containing an embedded penny-shaped crack and subjected to normal and radial impact. Quantitatively, the time-dependent stresses near the crack border can be described by the dynamic stress intensity factors. Their magnitude depends on time, on the material properties of the composite and on the relative size of the crack compared to the composite local geometry. Results obtained show that, for the same material properties and geometry of the composite, the dynamic stress intensity factors for an embedded (penny-shaped) crack reach their peak values within a shorter period of time and with a lower magnitude than the corresponding dynamic stress factors for a through-crack.

Spectroscopy of a one-dimensional V-shaped quantum well with a point impurity

NASA Astrophysics Data System (ADS)

Fassari, S.; Gadella, M.; Glasser, M. L.; Nieto, L. M.

2018-02-01

We consider the one-dimensional Hamiltonian with a V-shaped potential H0 = 1/2 [ -d2/dx2 + | x | ], decorated with a point impurity of either δ-type, or local δ‧-type or even nonlocal δ‧-type, thus yielding three exactly solvable models. We analyse the behaviour of the change in the energy levels when an interaction of the type - λ δ(x) or - λ δ(x -x0) is switched on. In the first case, even energy levels, pertaining to antisymmetric bound states, remain invariant with respect to λ even though odd energy levels, pertaining to symmetric bound states, decrease as λ increases. In the second, all energy levels decrease when the factor λ increases. A similar study has been performed for the so-called nonlocal δ‧ interaction, requiring a coupling constant renormalisation, which implies the replacement of the form factor λ by a renormalised form factor β. In terms of β, odd energy levels are unchanged. However, we show the existence of level crossings: after a fixed value of β the energy of each even level, with the natural exception of the first one, becomes lower than the constant energy of the previous odd level. Finally, we consider an interaction of the type - λδ(x) + μδ‧(x) , and analyse in detail the discrete spectrum of the resulting self-adjoint Hamiltonian.

Effect of high-power-laser with and without graphite coating on bonding of resin cement to lithium disilicate ceramic.

PubMed

Feitosa, Fernanda A; de Araújo, Rodrigo M; Tay, Franklin R; Niu, Lina; Pucci, César R

2017-12-12

The present study evaluated the effect of different high-power-laser surface treatments on the bond strength between resin cement and disilicate ceramic. Lithium disilicate ceramic specimens with truncated cones shape were prepared and divided into 5 groups: HF (hydrofluoric acid-etching), Er:YAG laser + HF, Graphite + Er:YAG laser + HF, Nd:YAG laser + HF, and Graphite + Nd:YAG laser + HF. The treated ceramic surfaces were characterized with scanning electron microscopy and surface roughness measurement. Hourglasses-shaped ceramic- resin bond specimens were prepared, thermomechanically cycled and stressed to failure under tension. The results showed that for both the factors "laser" and "graphite", statistically significant differences were observed (p < 0.05). Multiple-comparison tests performed on the "laser" factor were in the order: Er:YAG > Nd:YAG (p < 0.05), and on the "graphite" factor were in the order: graphite coating < without coating (p < 0.05). The Dunnett test showed that Er:YAG + HF had significantly higher tensile strength (p = 0.00). Higher surface roughness was achieved after Er:YAG laser treatment. Thus Er:YAG laser treatment produces higher bond strength to resin cement than other surface treatment protocols. Surface-coating with graphite does not improve bonding of the laser-treated lithium disilicate ceramic to resin cement.

Impact of contextual factors and substance characteristics on perspectives toward cognitive enhancement.

PubMed

Sattler, Sebastian; Forlini, Cynthia; Racine, Eric; Sauer, Carsten

2013-01-01

Enhancing cognitive performance with substances--especially prescription drugs--is a fiercely debated topic among scholars and in the media. The empirical basis for these discussions is limited, given that the actual nature of factors that influence the acceptability of and willingness to use cognitive enhancement substances remains unclear. In an online factorial survey, contextual and substance-specific characteristics of substances that improve academic performance were varied experimentally and presented to respondents. Students in four German universities rated their willingness to use and moral acceptance of different substances for cognitive enhancement. We found that the overall willingness to use performance enhancing substances is low. Most respondents considered the use of these substances as morally unacceptable. Situational influences such as peer pressure, policies concerning substance use, relative performance level of peers, but also characteristics of the substance, such as perceptions of substance safety, shape the willingness and acceptability of using a substance to enhance academic performance. Among the findings is evidence of a contagion effect meaning that the willingness was higher when the respondents have more CE drug users in their social network. We also found deterrence effects from strong side effects of using the substance, as well as from policy regulations and sanctions. Regulations might activate social norms against usage and sanctions can be seen as costly to users. Moreover, enhancement substances seem to be most tempting to low performers to catch up with others compared to high performers. By identifying contextual factors and substance characteristics influencing the willingness and acceptability of cognitive enhancers, policy approaches could consider these insights to better manage the use of such substances.

Finger-Shaped GelForce: Sensor for Measuring Surface Traction Fields for Robotic Hand.

PubMed

Sato, K; Kamiyama, K; Kawakami, N; Tachi, S

2010-01-01

It is believed that the use of haptic sensors to measure the magnitude, direction, and distribution of a force will enable a robotic hand to perform dexterous operations. Therefore, we develop a new type of finger-shaped haptic sensor using GelForce technology. GelForce is a vision-based sensor that can be used to measure the distribution of force vectors, or surface traction fields. The simple structure of the GelForce enables us to develop a compact finger-shaped GelForce for the robotic hand. GelForce that is developed on the basis of an elastic theory can be used to calculate surface traction fields using a conversion equation. However, this conversion equation cannot be analytically solved when the elastic body of the sensor has a complicated shape such as the shape of a finger. Therefore, we propose an observational method and construct a prototype of the finger-shaped GelForce. By using this prototype, we evaluate the basic performance of the finger-shaped GelForce. Then, we conduct a field test by performing grasping operations using a robotic hand. The results of this test show that using the observational method, the finger-shaped GelForce can be successfully used in a robotic hand.

Aging and solid shape recognition: Vision and haptics.

PubMed

Norman, J Farley; Cheeseman, Jacob R; Adkins, Olivia C; Cox, Andrea G; Rogers, Connor E; Dowell, Catherine J; Baxter, Michael W; Norman, Hideko F; Reyes, Cecia M

2015-10-01

The ability of 114 younger and older adults to recognize naturally-shaped objects was evaluated in three experiments. The participants viewed or haptically explored six randomly-chosen bell peppers (Capsicum annuum) in a study session and were later required to judge whether each of twelve bell peppers was "old" (previously presented during the study session) or "new" (not presented during the study session). When recognition memory was tested immediately after study, the younger adults' (Experiment 1) performance for vision and haptics was identical when the individual study objects were presented once. Vision became superior to haptics, however, when the individual study objects were presented multiple times. When 10- and 20-min delays (Experiment 2) were inserted in between study and test sessions, no significant differences occurred between vision and haptics: recognition performance in both modalities was comparable. When the recognition performance of older adults was evaluated (Experiment 3), a negative effect of age was found for visual shape recognition (younger adults' overall recognition performance was 60% higher). There was no age effect, however, for haptic shape recognition. The results of the present experiments indicate that the visual recognition of natural object shape is different from haptic recognition in multiple ways: visual shape recognition can be superior to that of haptics and is affected by aging, while haptic shape recognition is less accurate and unaffected by aging. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improved Functional Properties and Efficiencies of Nitinol Wires Under High-Performance Shape Memory Effect (HP-SME)

NASA Astrophysics Data System (ADS)

Casati, R.; Saghafi, F.; Biffi, C. A.; Vedani, M.; Tuissi, A.

2017-10-01

Martensitic Ti-rich NiTi intermetallics are broadly used in various cyclic applications as actuators, which exploit the shape memory effect (SME). Recently, a new approach for exploiting austenitic Ni-rich NiTi shape memory alloys as actuators was proposed and named high-performance shape memory effect (HP-SME). HP-SME is based on thermal recovery of de-twinned martensite produced by mechanical loading of the parent phase. The aim of the manuscript consists in evaluating and comparing the fatigue and actuation properties of austenitic HP-SME wires and conventional martensitic SME wires. The effect of the thermomechanical cycling on the actuation response and the changes in the electrical resistivity of both shape memory materials were studied by performing the actuation tests at different stages of the fatigue life. Finally, the changes in the transition temperatures before and after cycling were also investigated by differential calorimetric tests.

Combination of optical shape measurement and augmented reality for task support: II. Real-time feedback of shape measurement results

NASA Astrophysics Data System (ADS)

Yamauchi, Makoto; Iwamoto, Kazuyo

2010-05-01

Line heating is a skilled task in shipbuilding to shape the outer plates of ship hulls. Real-time information on the deformation of the plates during the task would be helpful to workers performing this process. Therefore, we herein propose an interactive scheme for supporting workers performing line heating; the system provides such information through an optical shape measurement instrument combined with an augmented reality (AR) system. The instrument was designed and fabricated so that the measured data were represented using coordinates based on fiducial markers. Since the markers were simultaneously used in the AR system for the purpose of positioning, the data could then be displayed to the workers through a head-mounted display as a virtual image overlaid on the plates. Feedback of the shape measurement results was thus performed in real time using the proposed system.

IMPROVED ALGORITHMS FOR RADAR-BASED RECONSTRUCTION OF ASTEROID SHAPES

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

Greenberg, Adam H.; Margot, Jean-Luc

We describe our implementation of a global-parameter optimizer and Square Root Information Filter into the asteroid-modeling software shape. We compare the performance of our new optimizer with that of the existing sequential optimizer when operating on various forms of simulated data and actual asteroid radar data. In all cases, the new implementation performs substantially better than its predecessor: it converges faster, produces shape models that are more accurate, and solves for spin axis orientations more reliably. We discuss potential future changes to improve shape's fitting speed and accuracy.

Body Fineness Ratio as a Predictor of Maximum Prolonged-Swimming Speed in Coral Reef Fishes

PubMed Central

Walker, Jeffrey A.; Alfaro, Michael E.; Noble, Mae M.; Fulton, Christopher J.

2013-01-01

The ability to sustain high swimming speeds is believed to be an important factor affecting resource acquisition in fishes. While we have gained insights into how fin morphology and motion influences swimming performance in coral reef fishes, the role of other traits, such as body shape, remains poorly understood. We explore the ability of two mechanistic models of the causal relationship between body fineness ratio and endurance swimming-performance to predict maximum prolonged-swimming speed (Umax) among 84 fish species from the Great Barrier Reef, Australia. A drag model, based on semi-empirical data on the drag of rigid, submerged bodies of revolution, was applied to species that employ pectoral-fin propulsion with a rigid body at U max. An alternative model, based on the results of computer simulations of optimal shape in self-propelled undulating bodies, was applied to the species that swim by body-caudal-fin propulsion at Umax. For pectoral-fin swimmers, Umax increased with fineness, and the rate of increase decreased with fineness, as predicted by the drag model. While the mechanistic and statistical models of the relationship between fineness and Umax were very similar, the mechanistic (and statistical) model explained only a small fraction of the variance in Umax. For body-caudal-fin swimmers, we found a non-linear relationship between fineness and Umax, which was largely negative over most of the range of fineness. This pattern fails to support either predictions from the computational models or standard functional interpretations of body shape variation in fishes. Our results suggest that the widespread hypothesis that a more optimal fineness increases endurance-swimming performance via reduced drag should be limited to fishes that swim with rigid bodies. PMID:24204575

Human action classification using procrustes shape theory

NASA Astrophysics Data System (ADS)

Cho, Wanhyun; Kim, Sangkyoon; Park, Soonyoung; Lee, Myungeun

2015-02-01

In this paper, we propose new method that can classify a human action using Procrustes shape theory. First, we extract a pre-shape configuration vector of landmarks from each frame of an image sequence representing an arbitrary human action, and then we have derived the Procrustes fit vector for pre-shape configuration vector. Second, we extract a set of pre-shape vectors from tanning sample stored at database, and we compute a Procrustes mean shape vector for these preshape vectors. Third, we extract a sequence of the pre-shape vectors from input video, and we project this sequence of pre-shape vectors on the tangent space with respect to the pole taking as a sequence of mean shape vectors corresponding with a target video. And we calculate the Procrustes distance between two sequences of the projection pre-shape vectors on the tangent space and the mean shape vectors. Finally, we classify the input video into the human action class with minimum Procrustes distance. We assess a performance of the proposed method using one public dataset, namely Weizmann human action dataset. Experimental results reveal that the proposed method performs very good on this dataset.

Space Mission Human Reliability Analysis (HRA) Project

NASA Technical Reports Server (NTRS)

Boyer, Roger

2014-01-01

The purpose of the Space Mission Human Reliability Analysis (HRA) Project is to extend current ground-based HRA risk prediction techniques to a long-duration, space-based tool. Ground-based HRA methodology has been shown to be a reasonable tool for short-duration space missions, such as Space Shuttle and lunar fly-bys. However, longer-duration deep-space missions, such as asteroid and Mars missions, will require the crew to be in space for as long as 400 to 900 day missions with periods of extended autonomy and self-sufficiency. Current indications show higher risk due to fatigue, physiological effects due to extended low gravity environments, and others, may impact HRA predictions. For this project, Safety & Mission Assurance (S&MA) will work with Human Health & Performance (HH&P) to establish what is currently used to assess human reliabiilty for human space programs, identify human performance factors that may be sensitive to long duration space flight, collect available historical data, and update current tools to account for performance shaping factors believed to be important to such missions. This effort will also contribute data to the Human Performance Data Repository and influence the Space Human Factors Engineering research risks and gaps (part of the HRP Program). An accurate risk predictor mitigates Loss of Crew (LOC) and Loss of Mission (LOM).The end result will be an updated HRA model that can effectively predict risk on long-duration missions.

The Unfinished Stories of Two First Nations Mothers

ERIC Educational Resources Information Center

Moayeri, Maryam; Smith, Jane

2010-01-01

This study is shaped by an underlying theoretical assumption that literacy is a cultural practice, shaped by and shaping social factors such as culture, gender, politics, and economics. As a result, this article focuses on the literacy practices of two mothers who participated in the study. Because of their Aboriginal ancestry and the historical…

Global Nonlinear Optimization for the Interpretation of Magnetic Anomalies Over Idealized Geological Bodies for Ore Exploration - An Insight about Uncertainty

NASA Astrophysics Data System (ADS)

Biswas, A.

2016-12-01

A Very Fast Simulated Annealing (VFSA) global optimization code is produced for elucidation of magnetic data over various idealized bodies for mineral investigation. The way of uncertainty in the interpretation is additionally analyzed in the present study. This strategy fits the watched information exceptionally well by some straightforward geometrically body in the confined class of Sphere, horizontal cylinder, thin dyke and sheet type models. The consequences of VFSA improvement uncover that different parameters demonstrate various identical arrangements when state of the objective body is not known and shape factor "q" is additionally advanced together with other model parameters. The study uncovers that amplitude coefficient k is firmly subject to shape factor. This demonstrates there is multi-model sort vulnerability between these two model parameters. Be that as it may, the assessed estimations of shape factor from different VFSA runs without a doubt show whether the subsurface structure is sphere, horizontal cylinder, and dyke or sheet type structure. Thus, the precise shape element (2.5 for sphere, 2.0 for horizontal cylinder and 1.0 for dyke and sheet) is settled and improvement procedure is rehashed. Next, altering the shape factor and investigation of uncertainty as well as scatter-plots demonstrates a very much characterized uni-model characteristics. The mean model figured in the wake of settling the shape factor gives the highest dependable results. Inversion of noise-free and noisy synthetic data information and additionally field information shows the adequacy of the methodology. The procedure has been carefully and practically connected to five genuine field cases with the nearness of mineralized bodies covered at various profundities in the subsurface and complex geological settings. The method can be to a great degree appropriate for mineral investigation, where the attractive information is seen because of mineral body established in the shallow/deeper subsurface and the calculation time for the entire procedure are short. Keywords: Magnetic anomaly, idealized body, uncertainty, VFSA, multiple structure, ore exploration.

Analyzing key performance indicators (KPIs) for E-commerce and Internet marketing of elderly products: a review.

PubMed

Tsai, Yuan-Cheng; Cheng, Yu-Tien

2012-01-01

With the transformation of its population structure and economic environment, Taiwan is rapidly becoming an aging society. There is a growing need for elderly products, and therefore the operation of web shops that sell elderly products is important. In an era which values performance management, searching for key performance indicators (KPIs) helps to reveal, if the goals of a web shop are achieved. In the current study, researchers adopted the constructs of the Balanced Scorecard (BSC) to evaluate web shop performance. Additionally, the Delphi method, along with questionnaires, was used to develop 29 indicators. Finally, the decision making trial and evaluation laboratory (DEMATEL) method assisted in identifying the level of importance of the constructs, in which "internal process" ranked top, followed by "learning and growth", "customer", and "financial". "Internal process" was the key construct that impacted other factors, while "customer" was an important construct affected by other factors. By understanding the influences and relationships among the constructs, enterprises can conduct additional monitoring and management to achieve functions of prevention, continuous improvement, and innovation in order to shape their core competence. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Statistical shape analysis using 3D Poisson equation--A quantitatively validated approach.

PubMed

Gao, Yi; Bouix, Sylvain

2016-05-01

Statistical shape analysis has been an important area of research with applications in biology, anatomy, neuroscience, agriculture, paleontology, etc. Unfortunately, the proposed methods are rarely quantitatively evaluated, and as shown in recent studies, when they are evaluated, significant discrepancies exist in their outputs. In this work, we concentrate on the problem of finding the consistent location of deformation between two population of shapes. We propose a new shape analysis algorithm along with a framework to perform a quantitative evaluation of its performance. Specifically, the algorithm constructs a Signed Poisson Map (SPoM) by solving two Poisson equations on the volumetric shapes of arbitrary topology, and statistical analysis is then carried out on the SPoMs. The method is quantitatively evaluated on synthetic shapes and applied on real shape data sets in brain structures. Copyright © 2016 Elsevier B.V. All rights reserved.

Shaping up: a geometric morphometric approach to assemblage ecomorphology.

PubMed

Bower, L M; Piller, K R

2015-09-01

This study adopts an ecomorphological approach to test the utility of body shape as a predictor of niche relationships among a stream fish assemblage of the Tickfaw River (Lake Pontchartrain Basin) in southeastern Louisiana, U.S.A. To examine the potential influence of evolutionary constraints, analyses were performed with and without the influence of phylogeny. Fish assemblages were sampled throughout the year, and ecological data (habitat and tropic guild) and body shape (geometric morphometric) data were collected for each fish specimen. Multivariate analyses were performed to examine relationships and differences between body shape and ecological data. Results indicate that a relationship exists between body shape and trophic guild as well as flow regime, but no significant correlation between body shape and substratum was found. Body shape was a reliable indicator of position within assemblage niche space. © 2015 The Fisheries Society of the British Isles.

Direct activation of Shroom3 transcription by Pitx proteins drives epithelial morphogenesis in the developing gut

PubMed Central

Chung, Mei-I; Nascone-Yoder, Nanette M.; Grover, Stephanie A.; Drysdale, Thomas A.; Wallingford, John B.

2010-01-01

Individual cell shape changes are essential for epithelial morphogenesis. A transcriptional network for epithelial cell shape change is emerging in Drosophila, but this area remains largely unexplored in vertebrates. The distinction is important as so far, key downstream effectors of cell shape change in Drosophila appear not to be conserved. Rather, Shroom3 has emerged as a central effector of epithelial morphogenesis in vertebrates, driving both actin- and microtubule-based cell shape changes. To date, the morphogenetic role of Shroom3 has been explored only in the neural epithelium, so the broad expression of this gene raises two important questions: what are the requirements for Shroom3 in non-neural tissues and what factors control Shroom3 transcription? Here, we show in Xenopus that Shroom3 is essential for cell shape changes and morphogenesis in the developing vertebrate gut and that Shroom3 transcription in the gut requires the Pitx1 transcription factor. Moreover, we show that Pitx proteins directly activate Shroom3 transcription, and we identify Pitx-responsive regulatory elements in the genomic DNA upstream of Shroom3. Finally, we show that ectopic expression of Pitx proteins is sufficient to induce Shroom3-dependent cytoskeletal reorganization and epithelial cell shape change. These data demonstrate new breadth to the requirements for Shroom3 in morphogenesis, and they also provide a cell-biological basis for the role of Pitx transcription factors in morphogenesis. More generally, these results provide a foundation for deciphering the transcriptional network that underlies epithelial cell shape change in developing vertebrates. PMID:20332151

Towards a framework for analyzing determinants of performance of community health workers in malaria prevention and control: a systematic review.

PubMed

Chipukuma, Helen Mwiinga; Zulu, Joseph Mumba; Jacobs, Choolwe; Chongwe, Gershom; Chola, Mumbi; Halwiindi, Hikabasa; Zgambo, Jessy; Michelo, Charles

2018-05-08

Community health workers (CHWs) are an important human resource in improving coverage of and success to interventions aimed at reducing malaria incidence. Evidence suggests that the performance of CHWs in malaria programs varies in different contexts. However, comprehensive frameworks, based on systematic reviews, to guide the analysis of determinants of performance of CHWs in malaria prevention and control programs are lacking. We systematically searched Google Scholar, Science Direct, and PubMed including reference lists that had English language publications. We included 16 full text articles that evaluated CHW performance in malaria control. Search terms were used and studies that had performance as an outcome of interest attributed to community-based interventions done by CHWs were included. Sixteen studies were included in the final review and were mostly on malaria Rapid Diagnosis and Treatment, as well as adherence to referral guidelines. Factors determining performance and effective implementation of CHW malaria programs included health system factors such as nature of training of CHWs; type of supervision including feedback process; availability of stocks, supplies, and job aids; nature of work environment and reporting systems; availability of financial resources and transport systems; types of remuneration; health staff confidence in CHWs; and workload. In addition, community dynamics such as nature of community connectedness and support from the community and utilization of services by the community also influenced performance. Furthermore, community health worker characteristics such marital status, sex, and CHW confidence levels also shaped CHW performance. Effectively analyzing and promoting the performance of CHWs in malaria prevention and control programs may require adopting a framework that considers health systems and community factors as well as community health worker characteristics.

Fabrication of bimetallic microfluidic surface-enhanced Raman scattering sensors on paper by screen printing.

PubMed

Qu, Lu-Lu; Song, Qi-Xia; Li, Yuan-Ting; Peng, Mao-Pan; Li, Da-Wei; Chen, Li-Xia; Fossey, John S; Long, Yi-Tao

2013-08-20

Au-Ag bimetallic microfluidic, dumbbell-shaped, surface enhanced Raman scattering (SERS) sensors were fabricated on cellulose paper by screen printing. These printed sensors rely on a sample droplet injection zone, and a SERS detection zone at either end of the dumbbell motif, fabricated by printing silver nanoparticles (Ag NPs) and gold nanoparticles (Au NPs) successively with microscale precision. The microfluidic channel was patterned using an insulating ink to connect these two zones and form a hydrophobic circuit. Owing to capillary action of paper in the millimeter-sized channels, the sensor could enable self-filtering of fluids to remove suspended particles within wastewater without pumping. This sensor also allows sensitive SERS detection, due to advantageous combination of the strong surface enhancement of Ag NPs and excellent chemical stability of Au NPs. The SERS performance of the sensors was investigated by employing the probe rhodamine 6G, a limit of detection (LOD) of 1.1×10(-13)M and an enhancement factor of 8.6×10(6) could be achieved. Moreover, the dumbbell-shaped bimetallic sensors exhibited good stability with SERS performance being maintained over 14 weeks in air, and high reproducibility with less than 15% variation in spot-to-spot SERS intensity. Using these dumbbell-shaped bimetallic sensors, substituted aromatic pollutants in wastewater samples could be quantitatively analyzed, which demonstrated their excellent capability for rapid trace pollutant detection in wastewater samples in the field without pre-separation. Copyright © 2013 Elsevier B.V. All rights reserved.

A Wind Tunnel Study of Icing Effects on a Business Jet Airfoil

NASA Technical Reports Server (NTRS)

Addy, Harold E., Jr.; Broeren, Andy P.; Zoeckler, Joesph G.; Lee, Sam

2003-01-01

Aerodynamic wind tunnel tests were conducted to study the effects of various ice accretions on the aerodynamic performance of a 36-inch chord, two-dimensional business jet airfoil. Eight different ice shape configurations were tested. Four were castings made from molds of ice shapes accreted in an icing wind tunnel. Two were made using computationally smoothed tracings of two of the ice shapes accreted in the icing tunnel. These smoothed profiles were then extended in the spanwise direction to form a two-dimensional ice shape. The final two configurations were formed by applying grit to the smoothed ice shapes. The ice shapes resulted in as much as 48% reduction in maximum lift coefficient from that of the clean airfoil. Large increases in drag and changes in pitching moment were also observed. The castings and their corresponding smoothed counterparts yielded similar results. Little change in performance was observed with the addition of grit to the smoothed ice shapes. Changes in the Reynolds number (from 3 x 10(exp 6) to 10.5 x 10(exp 6) and Mach number (from 0.12 to 0.28) did not significantly affect the iced-airfoil performance coefficients.

A water-responsive shape memory ionomer with permanent shape reconfiguration ability

NASA Astrophysics Data System (ADS)

Bai, Yongkang; Zhang, Jiwen; Tian, Ran; Chen, Xin

2018-04-01

In this work, a water-responsive shape memory ionomer with high toughness was fabricated by cross-linking hyaluronic acid sodium (HAS) and polyvinyl alcohol (PVA) through coordination interactions. The strong Fe3+-carboxyl (from HAS) coordination interactions served as main physical cross-linking points for the performance of water-responsive shape memory, which associated with the flexibility of PVA chain producing excellent mechanical properties of this ionomer. The optimized ionomer was not only able to recover to its original shape within just 22 s by exposing to water, but exhibited high tensile strength up to 35.4 MPa and 4 times higher tractility than the ionomer without PVA. Moreover, the ionomers can be repeatedly programed to various new permanent shapes on demand due to the reversible physical interactions, which still performed complete and fast geometric recovery under stimuli even after 4 cycles of reprograming with 3 different shapes. The excellent shape memory and strong mechanical behaviors make our ionomers significant and promising smart materials for variety of applications.

Macroecological factors shape local-scale spatial patterns in agriculturalist settlements.

PubMed

Tao, Tingting; Abades, Sebastián; Teng, Shuqing; Huang, Zheng Y X; Reino, Luís; Chen, Bin J W; Zhang, Yong; Xu, Chi; Svenning, Jens-Christian

2017-11-15

Macro-scale patterns of human systems ranging from population distribution to linguistic diversity have attracted recent attention, giving rise to the suggestion that macroecological rules shape the assembly of human societies. However, in which aspects the geography of our own species is shaped by macroecological factors remains poorly understood. Here, we provide a first demonstration that macroecological factors shape strong local-scale spatial patterns in human settlement systems, through an analysis of spatial patterns in agriculturalist settlements in eastern mainland China based on high-resolution Google Earth images. We used spatial point pattern analysis to show that settlement spatial patterns are characterized by over-dispersion at fine spatial scales (0.05-1.4 km), consistent with territory segregation, and clumping at coarser spatial scales beyond the over-dispersion signals, indicating territorial clustering. Statistical modelling shows that, at macroscales, potential evapotranspiration and topographic heterogeneity have negative effects on territory size, but positive effects on territorial clustering. These relationships are in line with predictions from territory theory for hunter-gatherers as well as for many animal species. Our results help to disentangle the complex interactions between intrinsic spatial processes in agriculturalist societies and external forcing by macroecological factors. While one may speculate that humans can escape ecological constraints because of unique abilities for environmental modification and globalized resource transportation, our work highlights that universal macroecological principles still shape the geography of current human agricultural societies. © 2017 The Author(s).

Individual risk factors for carpal tunnel syndrome: an evaluation of body mass index, wrist index and hand anthropometric measurements.

PubMed

Boz, Cavit; Ozmenoglu, Mehmet; Altunayoglu, Vildan; Velioglu, Sibel; Alioglu, Zekeriya

2004-09-01

In this study we aimed to identify the role of the body mass index (BMI), wrist index and hand anthropometric measures as risk factors for carpal tunnel syndrome (CTS) in both genders. Based on clinical and electrophysiologic diagnostic criteria, 154 female and 44 male CTS patients, as well as 150 female and 44 male age-matched control subjects, were selected. BMI, wrist index, hand shape index, digit index and hand length/height ratio were compared between the CTS patients and the control subjects for each gender separately. Mean BMI was found to be a significant risk factor for CTS in both genders. The wrist index was found to be higher in female (P < 0.001) and in male (P = 0.034) CTS groups than in the respective control groups. Logistic regression analysis revealed the wrist index to be an independent risk factor in females, but not in males. Shape and digit indices were significantly higher in female CTS patients than in corresponding control subjects, and regression analysis showed the shape and digit indices to be independent risk factors for CTS. In the male CTS group, the shape and digit indices did not significantly differ from their controls. Differences in the hand length/height ratio were not statistically significant in female and male CTS patients compared to their controls and it was not found to be an independent risk factor for CTS. Our study confirmed BMI as an independent risk factor for CTS in both genders. Hand and wrist anthropometrics were found to be independent risk factors for CTS in females, but not in males.

Development for 2D pattern quantification method on mask and wafer

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Toyoda, Yasutaka; Wang, Zhigang

2010-03-01

We have developed the effective method of mask and silicon 2-dimensional metrology. The aim of this method is evaluating the performance of the silicon corresponding to Hotspot on a mask. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and mask manufacture, and this has a big impact on the semiconductor market that centers on the mask business. 2-dimensional Shape quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. On the other hand, there is roughness in the silicon shape made from a mass-production line. Moreover, there is variation in the silicon shape. For this reason, quantification of silicon shape is important, in order to estimate the performance of a pattern. In order to quantify, the same shape is equalized in two dimensions. And the method of evaluating based on the shape is popular. In this study, we conducted experiments for averaging method of the pattern (Measurement Based Contouring) as two-dimensional mask and silicon evaluation technique. That is, observation of the identical position of a mask and a silicon was considered. It is possible to analyze variability of the edge of the same position with high precision. The result proved its detection accuracy and reliability of variability on two-dimensional pattern (mask and silicon) and is adaptable to following fields of mask quality management. - Estimate of the correlativity of shape variability and a process margin. - Determination of two-dimensional variability of pattern. - Verification of the performance of the pattern of various kinds of Hotspots. In this report, we introduce the experimental results and the application. We expect that the mask measurement and the shape control on mask production will make a huge contribution to mask yield-enhancement and that the DFM solution for mask quality control process will become much more important technology than ever. It is very important to observe the shape of the same location of Design, Mask, and Silicon in such a viewpoint.

A proposed standard round compact specimen for plane strain fracture toughness testing

NASA Technical Reports Server (NTRS)

Underwood, J. H.; Newman, J. C., Jr.; Seeley, R. R.

1980-01-01

A round, disk-shaped specimen is proposed as a standard test specimen for addition to ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-78A). The specimen is diametrically cracked, and loaded in the same way as the existing standard compact specimen. Tests and analyses were performed to verify that the proposed round compact specimen and associated stress intensity factor K solution are appropriate for a standard plane strain fracture toughness test. The use of the round compact specimen for other fracture tests is described.

Improving child welfare performance through supervisory use of client outcome data.

PubMed

Moore, T D; Rapp, C A; Roberts, B

2000-01-01

Despite their benefits, there is little evidence that outcome data are being widely used by program managers or field level supervisors. Three interdependent factors that facilitate the use of outcome data are well-constructed reports, and organizational culture that supports learning and outcome achievement, and managerial skills in interpreting data and taking relevant action. This article describes an outcome reporting package and training oriented toward frontline supervisors to help them use outcome data, shape a learning culture, interpret data, and take focused action toward improving outcomes for children and families.

Control and prediction of the course of brewery fermentations by gravimetric analysis.

PubMed

Kosín, P; Savel, J; Broz, A; Sigler, K

2008-01-01

A simple, fast and cheap test suitable for predicting the course of brewery fermentations based on mass analysis is described and its efficiency is evaluated. Compared to commonly used yeast vitality tests, this analysis takes into account wort composition and other factors that influence fermentation performance. It can be used to predict the shape of the fermentation curve in brewery fermentations and in research and development projects concerning yeast vitality, fermentation conditions and wort composition. It can also be a useful tool for homebrewers to control their fermentations.

Development and evaluation of statistical shape modeling for principal inner organs on torso CT images.

PubMed

Zhou, Xiangrong; Xu, Rui; Hara, Takeshi; Hirano, Yasushi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Kido, Shoji; Fujita, Hiroshi

2014-07-01

The shapes of the inner organs are important information for medical image analysis. Statistical shape modeling provides a way of quantifying and measuring shape variations of the inner organs in different patients. In this study, we developed a universal scheme that can be used for building the statistical shape models for different inner organs efficiently. This scheme combines the traditional point distribution modeling with a group-wise optimization method based on a measure called minimum description length to provide a practical means for 3D organ shape modeling. In experiments, the proposed scheme was applied to the building of five statistical shape models for hearts, livers, spleens, and right and left kidneys by use of 50 cases of 3D torso CT images. The performance of these models was evaluated by three measures: model compactness, model generalization, and model specificity. The experimental results showed that the constructed shape models have good "compactness" and satisfied the "generalization" performance for different organ shape representations; however, the "specificity" of these models should be improved in the future.

A comparison of performance of lightweight mirrors

NASA Technical Reports Server (NTRS)

Cho, Myung K.; Richard, Ralph M.; Hileman, Edward A.

1990-01-01

Four lightweight solid contoured back mirror shapes (a double arch, a single arch, a modified single arch, and a double concave mirror) and a cellular sandwich lightweight meniscus mirror, have been considered for the primary mirror of the Space Infrared Telescope Facility (SIRTF). A parametric design study using these shapes for the SIRTF 40 inch primary mirror with a focal ratio f/2 is presented. Evaluations of the optical performance and fundamental frequency analyses are performed to compare relative merits of each mirror configuration. Included in these are structural, optical, and frequency analyses for (1) different back contour shapes, (2) different number and location of the support points, and (3) two gravity orientations (ZENITH and HORIZON positions). The finite element program NASTRAN is used to obtain the structural deflections of the optical surface. For wavefront error analysis, FRINGE and PCFRINGE programs are used to evaluate the optical performance. A scaling law relating the optical and structural performance for various mirror contoured back shapes is developed.

A comprehensive method for preliminary design optimization of axial gas turbine stages. II - Code verification

NASA Technical Reports Server (NTRS)

Jenkins, R. M.

1983-01-01

The present effort represents an extension of previous work wherein a calculation model for performing rapid pitchline optimization of axial gas turbine geometry, including blade profiles, is developed. The model requires no specification of geometric constraints. Output includes aerodynamic performance (adiabatic efficiency), hub-tip flow-path geometry, blade chords, and estimates of blade shape. Presented herein is a verification of the aerodynamic performance portion of the model, whereby detailed turbine test-rig data, including rig geometry, is input to the model to determine whether tested performance can be predicted. An array of seven (7) NASA single-stage axial gas turbine configurations is investigated, ranging in size from 0.6 kg/s to 63.8 kg/s mass flow and in specific work output from 153 J/g to 558 J/g at design (hot) conditions; stage loading factor ranges from 1.15 to 4.66.

Learning to ignore: acquisition of sustained attentional suppression.

PubMed

Dixon, Matthew L; Ruppel, Justin; Pratt, Jay; De Rosa, Eve

2009-04-01

We examined whether the selection mechanisms committed to the suppression of ignored stimuli can be modified by experience to produce a sustained, rather than transient, change in behavior. Subjects repeatedly ignored the shape of stimuli, while attending to their color. On subsequent attention to shape, there was a robust and sustained decrement in performance that was selective to when shape was ignored across multiple-color-target contexts, relative to a single-color-target context. Thus, amount of time ignored was not sufficient to induce a sustained performance decrement. Moreover, in this group, individual differences in initial color target selection were associated with the subsequent performance decrement when attending to previously ignored stimuli. Accompanying this sustained decrement in performance was a transfer in the locus of suppression from an exemplar (e.g., a circle) to a feature (i.e., shape) level of representation. These data suggest that learning can influence attentional selection by sustained attentional suppression of ignored stimuli.

Identification and detection of simple 3D objects with severely blurred vision.

PubMed

Kallie, Christopher S; Legge, Gordon E; Yu, Deyue

2012-12-05

Detecting and recognizing three-dimensional (3D) objects is an important component of the visual accessibility of public spaces for people with impaired vision. The present study investigated the impact of environmental factors and object properties on the recognition of objects by subjects who viewed physical objects with severely reduced acuity. The experiment was conducted in an indoor testing space. We examined detection and identification of simple convex objects by normally sighted subjects wearing diffusing goggles that reduced effective acuity to 20/900. We used psychophysical methods to examine the effect on performance of important environmental variables: viewing distance (from 10-24 feet, or 3.05-7.32 m) and illumination (overhead fluorescent and artificial window), and object variables: shape (boxes and cylinders), size (heights from 2-6 feet, or 0.61-1.83 m), and color (gray and white). Object identification was significantly affected by distance, color, height, and shape, as well as interactions between illumination, color, and shape. A stepwise regression analysis showed that 64% of the variability in identification could be explained by object contrast values (58%) and object visual angle (6%). When acuity is severely limited, illumination, distance, color, height, and shape influence the identification and detection of simple 3D objects. These effects can be explained in large part by the impact of these variables on object contrast and visual angle. Basic design principles for improving object visibility are discussed.

The parietal cortices participate in encoding, short-term memory, and decision-making related to tactile shape.

PubMed

Rojas-Hortelano, Eduardo; Concha, Luis; de Lafuente, Victor

2014-10-15

We routinely identify objects with our hands, and the physical attributes of touched objects are often held in short-term memory to aid future decisions. However, the brain structures that selectively process tactile information to encode object shape are not fully identified. In this article we describe the areas within the human cerebral cortex that specialize in encoding, short-term memory, and decision-making related to the shape of objects explored with the hand. We performed event-related functional magnetic resonance imaging in subjects performing a shape discrimination task in which two sequentially presented objects had to be explored to determine whether they had the same shape or not. To control for low-level and nonspecific brain activations, subjects performed a temperature discrimination task in which they compared the temperature of two spheres. Our results show that although a large network of brain structures is engaged in somatosensory processing, it is the areas lining the intraparietal sulcus that selectively participate in encoding, maintaining, and deciding on tactile information related to the shape of objects. Copyright © 2014 the American Physiological Society.

Numerical simulation on casing modification of a boiler water circulation pump

NASA Astrophysics Data System (ADS)

Li, Y. Z.; Fan, Y. Z.; Liu, S. H.; Wu, Y. L.; Zuo, Z. G.

2012-11-01

In this paper, hydraulic performance comparisons are made by numerical simulation method on boiler water circulation pump with casings of different shapes. The existing pump adopts a semispherical casing and a garlic-shaped casing. Results show that in the garlic-shaped casing noticeable swirling vortex can be found in the top region of the discharge nozzle, and semispherical casing has better performance in hydraulic efficiency and head.

Wall mechanics and exocytosis define the shape of growth domains in fission yeast.

PubMed

Abenza, Juan F; Couturier, Etienne; Dodgson, James; Dickmann, Johanna; Chessel, Anatole; Dumais, Jacques; Carazo Salas, Rafael E

2015-10-12

The amazing structural variety of cells is matched only by their functional diversity, and reflects the complex interplay between biochemical and mechanical regulation. How both regulatory layers generate specifically shaped cellular domains is not fully understood. Here, we report how cell growth domains are shaped in fission yeast. Based on quantitative analysis of cell wall expansion and elasticity, we develop a model for how mechanics and cell wall assembly interact and use it to look for factors underpinning growth domain morphogenesis. Surprisingly, we find that neither the global cell shape regulators Cdc42-Scd1-Scd2 nor the major cell wall synthesis regulators Bgs1-Bgs4-Rgf1 are reliable predictors of growth domain geometry. Instead, their geometry can be defined by cell wall mechanics and the cortical localization pattern of the exocytic factors Sec6-Syb1-Exo70. Forceful re-directioning of exocytic vesicle fusion to broader cortical areas induces proportional shape changes to growth domains, demonstrating that both features are causally linked.

An assessment technique for computer-socket manufacturing

PubMed Central

Sanders, Joan; Severance, Michael

2015-01-01

An assessment strategy is presented for testing the quality of carving and forming of individual computer aided manufacturing facilities. The strategy is potentially useful to facilities making sockets and companies marketing manufacturing equipment. To execute the strategy, an evaluator fabricates a collection of test models and sockets using the manufacturing suite under evaluation, and then measures their shapes using scanning equipment. Overall socket quality is assessed by comparing socket shapes with electronic file shapes. Then model shapes are compared with electronic file shapes to characterize carving performance. Socket shapes are compared with model shapes to characterize forming performance. The mean radial error (MRE), which is the average difference in radii between the two shapes being compared, provides insight into sizing quality. Inter-quartile range (IQR), the range of radial error for the best matched half of the points on the surfaces being compared, provides insight into shape quality. By determining MRE and IQR for carving and forming separately, the source(s) of socket shape error may be pinpointed. The developed strategy may provide a useful tool to the prosthetics community and industry to help identify problems and limitations in computer aided manufacturing and insight into appropriate modifications to overcome them. PMID:21938663

Haptic shape discrimination and interhemispheric communication.

PubMed

Dowell, Catherine J; Norman, J Farley; Moment, Jackie R; Shain, Lindsey M; Norman, Hideko F; Phillips, Flip; Kappers, Astrid M L

2018-01-10

In three experiments participants haptically discriminated object shape using unimanual (single hand explored two objects) and bimanual exploration (both hands were used, but each hand, left or right, explored a separate object). Such haptic exploration (one versus two hands) requires somatosensory processing in either only one or both cerebral hemispheres; previous studies related to the perception of shape/curvature found superior performance for unimanual exploration, indicating that shape comparison is more effective when only one hemisphere is utilized. The current results, obtained for naturally shaped solid objects (bell peppers, Capsicum annuum) and simple cylindrical surfaces demonstrate otherwise: bimanual haptic exploration can be as effective as unimanual exploration, showing that there is no necessary reduction in ability when haptic shape comparison requires interhemispheric communication. We found that while successive bimanual exploration produced high shape discriminability, the participants' bimanual performance deteriorated for simultaneous shape comparisons. This outcome suggests that either interhemispheric interference or the need to attend to multiple objects simultaneously reduces shape discrimination ability. The current results also reveal a significant effect of age: older adults' shape discrimination abilities are moderately reduced relative to younger adults, regardless of how objects are manipulated (left hand only, right hand only, or bimanual exploration).

A theoretical framework for holistic hospital management in the Japanese healthcare context.

PubMed

Liu, Hu-Chen

2013-11-01

This paper develops a conceptual framework for performance measurement as a pilot study on holistic hospital management in the Japanese healthcare context. We primarily used two data sources as well as expert statements obtained through interviews: a systematic review of literature and a questionnaire survey to healthcare experts. The systematic survey searched PubMed and PubMed Central, and 24 relevant papers were elicited. The expert questionnaire asked respondents to rate the degree of "usefulness" for each of 66 indicators on a three-point scale. Applying the theoretical framework, a minimum set of performance indicators was selected for holistic hospital management, which well fit the healthcare context in Japan. This indicator set comprised 35 individual indicators and several factors measured through questionnaire surveys. The indicators were confirmed by expert judgments from viewpoints of face, content and construct validities as well as their usefulness. A theoretical framework of performance measurement was established from primary healthcare stakeholders' perspectives. Performance indicators were largely divided into healthcare outcomes and performance shaping factors. Indicators in the former category may be applied for the detection of operational problems, while their latent causes can be effectively addressed by the latter category in terms of process, structure and culture/climate within the organization. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Full parabolic trough qualification from prototype to demonstration loop

NASA Astrophysics Data System (ADS)

Janotte, Nicole; Lüpfert, Eckhard; Pottler, Klaus; Schmitz, Mark

2017-06-01

On the example of the HelioTrough® collector development the full accompanying and supporting qualification program for large-scale parabolic trough collectors for solar thermal power plants is described from prototype to demonstration loop scale. In the evaluation process the actual state and the optimization potential are assessed. This includes the optical and geometrical performance determined by concentrator shape, deformation, assembly quality and local intercept factor values. Furthermore, its mechanical performance in terms of tracking accuracy and torsional stiffness and its thermal system performance on the basis of the overall thermal output and heat loss are evaluated. Demonstration loop tests deliver results of collector modules statistical slope deviation of 1.9 to 2.6 mrad, intercept factor above 98%, peak optical performance of 81.6% and heat loss coefficients from field tests. The benefit of such a closely monitored development lies in prompt feedback on strengths, weaknesses and potential improvements on the new product at any development stage from first module tests until demonstration loop evaluation. The product developer takes advantage of the achieved technical maturity, already before the implementation in a commercial power plant. The well-understood performance characteristics allow the reduction of safety margins making the new HelioTrough collector competitive from the start.

Antisymmetrization effects and the form factor of the real part of the. cap alpha. -nucleus potential

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

Majka, Z.; Budzanowski, A.; Grotowski, K.

1978-07-01

Antisymmetrization effects in the ..cap alpha..-nucleus interaction are investigated on the basis of a microscopic model in an one nucleon exchange approximation. It influences the form factor, increasing the halfway radius and decreasing the diffuseness as compared with the direct term of the potential only. Antisymmetrization preserves the shape of the potential which can be parametrized by a Woods-Saxon squared form. The phenomenological potential with the energy independent form factor of the above shape fits experimental data in a wide energy region.

Study on Miniaturized UHF Antennas for Partial Discharge Detection in High-Voltage Electrical Equipment.

PubMed

Liu, Jingcun; Zhang, Guogang; Dong, Jinlong; Wang, Jianhua

2015-11-20

Detecting partial discharge (PD) is an effective way to evaluate the condition of high-voltage electrical equipment insulation. The UHF detection method has attracted attention due to its high sensitivity, strong interference resistance, and ability to locate PDs. In this paper, a miniaturized equiangular spiral antenna (ESA) for UHF detection that uses a printed circuit board is proposed. I-shaped, L-shaped, and C-shaped microstrip baluns were designed to match the impedance between the ESA and coaxial cable and were verified by a vector network analyzer. For comparison, three other types of UHF antenna were also designed: A microstrip patch antenna, a microstrip slot antenna, and a printed dipole antenna. Their antenna factors were calibrated in a uniform electric field of different frequencies modulated in a gigahertz transverse electromagnetic cell. We performed comparison experiments on PD signal detection using an artificial defect model based on the international IEC 60270 standard. We also conducted time-delay test experiments on the ESA sensor to locate a PD source. It was found that the proposed ESA sensor meets PD signal detection requirements. The sensor's compact size makes it suitable for internal installation in high-voltage electrical equipment.

Study on Miniaturized UHF Antennas for Partial Discharge Detection in High-Voltage Electrical Equipment

PubMed Central

Liu, Jingcun; Zhang, Guogang; Dong, Jinlong; Wang, Jianhua

2015-01-01

Detecting partial discharge (PD) is an effective way to evaluate the condition of high-voltage electrical equipment insulation. The UHF detection method has attracted attention due to its high sensitivity, strong interference resistance, and ability to locate PDs. In this paper, a miniaturized equiangular spiral antenna (ESA) for UHF detection that uses a printed circuit board is proposed. I-shaped, L-shaped, and C-shaped microstrip baluns were designed to match the impedance between the ESA and coaxial cable and were verified by a vector network analyzer. For comparison, three other types of UHF antenna were also designed: A microstrip patch antenna, a microstrip slot antenna, and a printed dipole antenna. Their antenna factors were calibrated in a uniform electric field of different frequencies modulated in a gigahertz transverse electromagnetic cell. We performed comparison experiments on PD signal detection using an artificial defect model based on the international IEC 60270 standard. We also conducted time-delay test experiments on the ESA sensor to locate a PD source. It was found that the proposed ESA sensor meets PD signal detection requirements. The sensor’s compact size makes it suitable for internal installation in high-voltage electrical equipment. PMID:26610506

GDP-L-fucose is required for boundary definition in plants.

PubMed

Gonçalves, Beatriz; Maugarny-Calès, Aude; Adroher, Bernard; Cortizo, Millán; Borrega, Nero; Blein, Thomas; Hasson, Alice; Gineau, Emilie; Mouille, Grégory; Laufs, Patrick; Arnaud, Nicolas

2017-12-16

The CUP-SHAPED COTYLEDON (CUC) transcription factors control plant boundary formation, thus allowing the emergence of novel growth axes. While the developmental roles of the CUC genes in different organs and across species are well characterized, upstream and downstream events that contribute to their function are still poorly understood. To identify new players in this network, we performed a suppressor screen of CUC2g-m4, a line overexpressing CUC2 that has highly serrated leaves. We identified a mutation that simplifies leaf shape and affects MURUS1 (MUR1), which is responsible for GDP-L-fucose production. Using detailed morphometric analysis, we show that GDP-L-fucose has an essential role in leaf shape acquisition by sustaining differential growth at the leaf margins. Accordingly, reduced CUC2 expression levels are observed in mur1 leaves. Furthermore, genetic analyses reveal a conserved role for GDP-L-fucose in different developmental contexts where it contributes to organ separation in the same pathway as CUC2. Taken together, our results reveal that GDP-L-fucose is necessary for proper establishment of boundary domains in various developmental contexts. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Prenatal maternal stress shapes children's theory of mind: the QF2011 Queensland Flood Study.

PubMed

Simcock, G; Kildea, S; Elgbeili, G; Laplante, D P; Cobham, V; King, S

2017-08-01

Research shows that stress in pregnancy has powerful and enduring effects on many facets of child development, including increases in behavior problems and neurodevelopmental disorders. Theory of mind is an important aspect of child development that is predictive of successful social functioning and is impaired in children with autism. A number of factors related to individual differences in theory of mind have been identified, but whether theory of mind development is shaped by prenatal events has not yet been examined. In this study we utilized a sudden onset flood that occurred in Queensland, Australia in 2011 to examine whether disaster-related prenatal maternal stress predicts child theory of mind and whether sex of the child or timing of the stressor in pregnancy moderates these effects. Higher levels of flood-related maternal subjective stress, but not objective hardship, predicted worse theory of mind at 30 months (n=130). Further, maternal cognitive appraisal of the flood moderated the effects of stress in pregnancy on girls' theory of mind performance but not boys'. These results illuminate how stress in pregnancy can shape child development and the findings are discussed in relation to biological mechanisms in pregnancy and stress theory.

Health and Beauty Magazine Reading and Body Shape Concerns among a Group of College Women.

ERIC Educational Resources Information Center

Thomsen, Steven R.

2002-01-01

Examines three potential factors that might mediate the relationship between reading women's magazines and body shape and size concern. Finds that health and fitness magazine reading by college-aged women was linked directly to body shape concerns, indirectly through beliefs about men's thinness expectations. Explains that beauty and fashion…

Some Static Oscillatory and Free Body Tests of Blunt Bodies at Low Subsonic Speeds

NASA Technical Reports Server (NTRS)

Lichtenstein, Jacob H.; Fisher, Lewis R.; Scher, Stanley H.; Lawrence, George F.

1959-01-01

Some blunt-body shapes considered suitable for entry into the earth's atmosphere were tested by both static and oscillatory methods in the Langley stability tunnel. In addition, free-fall tests of some similar models were made in the Langley 20-foot free-spinning tunnel. The results of the tests show that increasing the flare of the body shape increased the dynamic stability and that for flat-faced shapes increasing the corner radius increased the stability. The test data from the Langley stability tunnel were used to compute the damping factor for the models tested in the langley 20-foot free-spinning tunnel. For these cases in which the damping factor was low, -1/2 or less, the stability was critical and sensitive to disturbance. When the damping factor was about -2, damping was generally obtained.

Determination of Dimensionless Attenuation Coefficient in Shaped Resonators

NASA Technical Reports Server (NTRS)

Daniels, C.; Steinetz, B.; Finkbeiner, J.; Raman, G.; Li, X.

2003-01-01

The value of dimensionless attenuation coefficient is an important factor when numerically predicting high-amplitude acoustic waves in shaped resonators. Both the magnitude of the pressure waveform and the quality factor rely heavily on this dimensionless parameter. Previous authors have stated the values used, but have not completely explained their methods. This work fully describes the methodology used to determine this important parameter. Over a range of frequencies encompassing the fundamental resonance, the pressure waves were experimentally measured at each end of the shaped resonators. At the corresponding dimensionless acceleration, the numerical code modeled the acoustic waveforms generated in the resonator using various dimensionless attenuation coefficients. The dimensionless attenuation coefficient that most closely matched the pressure amplitudes and quality factors of the experimental and numerical results was determined to be the value to be used in subsequent studies.

Parallel capillary-tube-based extension of thermoacoustic theory for random porous media.

PubMed

Roh, Heui-Seol; Raspet, Richard; Bass, Henry E

2007-03-01

Thermoacoustic theory is extended to stacks made of random bulk media. Characteristics of the porous stack such as the tortuosity and dynamic shape factors are introduced into the thermoacoustic wave equation in the low reduced frequency approximation. Basic thermoacoustic equations for a bulk porous medium are formulated analogously to the equations for a single pore. Use of different dynamic shape factors for the viscous and thermal effects is adopted and scaling using the dynamic shape factors and tortuosity is demonstrated. Comparisons of the calculated and experimentally derived thermoacoustic properties of reticulated vitreous carbon and aluminum foam show good agreement. A consistent mathematical model of sound propagation in a random porous medium with an imposed temperature is developed. This treatment leads to an expression for the coefficient of the temperature gradient in terms of scaled cylindrical thermoviscous functions.

Meteorological factors had more impact on airborne bacterial communities than air pollutants.

PubMed

Zhen, Quan; Deng, Ye; Wang, Yaqing; Wang, Xiaoke; Zhang, Hongxing; Sun, Xu; Ouyang, Zhiyun

2017-12-01

Airborne bacteria have gained increasing attention because they affect ecological balance and pose potential risks on human health. Recently, some studies have focused on the abundance and composition of airborne bacteria under heavy, hazy polluted weather in China, but they reached different conclusions about the comparisons with non-polluted days. In this study, we tested the hypothesis that meteorological factors could have a higher impact on shaping airborne bacterial communities than air pollutants by systematically monitoring the communities for 1year. Total suspended particles in Beijing were sampled for 20 consecutive days in each season of 2015. Bacterial abundance varied from 8.71×10 3 to 2.14×10 7 ribosomal operons per cubic meter according to the quantitative PCR analysis. There were relatively higher bacterial counts in spring and in autumn than in winter and summer. Airborne bacterial communities displayed a strong seasonality, according to the hierarchical cluster analysis. Only two exceptions overtook the seasonal trend, and both occurred in or after violent meteorological changes (sandstorm or rain). Aggregated boosted tree analysis performed on bacterial abundance showed that the dominant factors shaping bacterial communities were meteorological. They were air pressure in winter, air temperature and relative humidity in spring, RH in summer, and vapor pressure in autumn. Variation partition analysis on community structure showed that meteorological factors explained more variations than air pollutants. Therefore, both of the two models verified our hypothesis that the differences in airborne bacterial communities in polluted days or non-polluted days were mainly driven by the discrepancies of meteorological factors rather than by the presence of air pollutants. Copyright © 2017 Elsevier B.V. All rights reserved.

Clinical implementation of MOSFET detectors for dosimetry in electron beams.

PubMed

Bloemen-van Gurp, Esther J; Minken, Andre W H; Mijnheer, Ben J; Dehing-Oberye, Cary J G; Lambin, Philippe

2006-09-01

To determine the factors converting the reading of a MOSFET detector placed on the patient's skin without additional build-up to the dose at the depth of dose maximum (D(max)) and investigate their feasibility for in vivo dose measurements in electron beams. Factors were determined to relate the reading of a MOSFET detector to D(max) for 4 - 15 MeV electron beams in reference conditions. The influence of variation in field size, SSD, angle and field shape on the MOSFET reading, obtained without additional build-up, was evaluated using 4, 8 and 15 MeV beams and compared to ionisation chamber data at the depth of dose maximum (z(max)). Patient entrance in vivo measurements included 40 patients, mostly treated for breast tumours. The MOSFET reading, converted to D(max), was compared to the dose prescribed at this depth. The factors to convert MOSFET reading to D(max) vary between 1.33 and 1.20 for the 4 and 15 MeV beams, respectively. The SSD correction factor is approximately 8% for a change in SSD from 95 to 100 cm, and 2% for each 5-cm increment above 100 cm SSD. A correction for fields having sides smaller than 6 cm and for irregular field shape is also recommended. For fields up to 20 x 20 cm(2) and for oblique incidence up to 45 degrees, a correction is not necessary. Patient measurements demonstrated deviations from the prescribed dose with a mean difference of -0.7% and a standard deviation of 2.9%. Performing dose measurements with MOSFET detectors placed on the patient's skin without additional build-up is a well suited technique for routine dose verification in electron beams, when applying the appropriate conversion and correction factors.

Prediction of the Wall Factor of Arbitrary Particle Settling through Various Fluid Media in a Cylindrical Tube Using Artificial Intelligence

PubMed Central

Li, Mingzhong; Xue, Jianquan; Li, Yanchao; Tang, Shukai

2014-01-01

Considering the influence of particle shape and the rheological properties of fluid, two artificial intelligence methods (Artificial Neural Network and Support Vector Machine) were used to predict the wall factor which is widely introduced to deduce the net hydrodynamic drag force of confining boundaries on settling particles. 513 data points were culled from the experimental data of previous studies, which were divided into training set and test set. Particles with various shapes were divided into three kinds: sphere, cylinder, and rectangular prism; feature parameters of each kind of particle were extracted; prediction models of sphere and cylinder using artificial neural network were established. Due to the little number of rectangular prism sample, support vector machine was used to predict the wall factor, which is more suitable for addressing the problem of small samples. The characteristic dimension was presented to describe the shape and size of the diverse particles and a comprehensive prediction model of particles with arbitrary shapes was established to cover all types of conditions. Comparisons were conducted between the predicted values and the experimental results. PMID:24772024

Prediction of the wall factor of arbitrary particle settling through various fluid media in a cylindrical tube using artificial intelligence.

PubMed

Li, Mingzhong; Zhang, Guodong; Xue, Jianquan; Li, Yanchao; Tang, Shukai

2014-01-01

Considering the influence of particle shape and the rheological properties of fluid, two artificial intelligence methods (Artificial Neural Network and Support Vector Machine) were used to predict the wall factor which is widely introduced to deduce the net hydrodynamic drag force of confining boundaries on settling particles. 513 data points were culled from the experimental data of previous studies, which were divided into training set and test set. Particles with various shapes were divided into three kinds: sphere, cylinder, and rectangular prism; feature parameters of each kind of particle were extracted; prediction models of sphere and cylinder using artificial neural network were established. Due to the little number of rectangular prism sample, support vector machine was used to predict the wall factor, which is more suitable for addressing the problem of small samples. The characteristic dimension was presented to describe the shape and size of the diverse particles and a comprehensive prediction model of particles with arbitrary shapes was established to cover all types of conditions. Comparisons were conducted between the predicted values and the experimental results.

Microstructural effect on radiative scattering coefficient and asymmetry factor of anisotropic thermal barrier coatings

NASA Astrophysics Data System (ADS)

Chen, X. W.; Zhao, C. Y.; Wang, B. X.

2018-05-01

Thermal barrier coatings are common porous materials coated on the surface of devices operating under high temperatures and designed for heat insulation. This study presents a comprehensive investigation on the microstructural effect on radiative scattering coefficient and asymmetry factor of anisotropic thermal barrier coatings. Based on the quartet structure generation set algorithm, the finite-difference-time-domain method is applied to calculate angular scattering intensity distribution of complicated random microstructure, which takes wave nature into account. Combining Monte Carlo method with Particle Swarm Optimization, asymmetry factor, scattering coefficient and absorption coefficient are retrieved simultaneously. The retrieved radiative properties are identified with the angular scattering intensity distribution under different pore shapes, which takes dependent scattering and anisotropic pore shape into account implicitly. It has been found that microstructure significantly affects the radiative properties in thermal barrier coatings. Compared with spherical shape, irregular anisotropic pore shape reduces the forward scattering peak. The method used in this paper can also be applied to other porous media, which designs a frame work for further quantitative study on porous media.

Aging and the visual, haptic, and cross-modal perception of natural object shape.

PubMed

Norman, J Farley; Crabtree, Charles E; Norman, Hideko F; Moncrief, Brandon K; Herrmann, Molly; Kapley, Noah

2006-01-01

One hundred observers participated in two experiments designed to investigate aging and the perception of natural object shape. In the experiments, younger and older observers performed either a same/different shape discrimination task (experiment 1) or a cross-modal matching task (experiment 2). Quantitative effects of age were found in both experiments. The effect of age in experiment 1 was limited to cross-modal shape discrimination: there was no effect of age upon unimodal (ie within a single perceptual modality) shape discrimination. The effect of age in experiment 2 was eliminated when the older observers were either given an unlimited amount of time to perform the task or when the number of response alternatives was decreased. Overall, the results of the experiments reveal that older observers can effectively perceive 3-D shape from both vision and haptics.

Influence of World and Gravity Model Selection on Surface Interacting Vehicle Simulations

NASA Technical Reports Server (NTRS)

Madden, Michael M.

2007-01-01

A vehicle simulation is surface-interacting if the state of the vehicle (position, velocity, and acceleration) relative to the surface is important. Surface-interacting simulations perform ascent, entry, descent, landing, surface travel, or atmospheric flight. Modeling of gravity is an influential environmental factor for surface-interacting simulations. Gravity is the free-fall acceleration observed from a world-fixed frame that rotates with the world. Thus, gravity is the sum of gravitation and the centrifugal acceleration due to the world s rotation. In surface-interacting simulations, the fidelity of gravity at heights above the surface is more significant than gravity fidelity at locations in inertial space. A surface-interacting simulation cannot treat the gravity model separately from the world model, which simulates the motion and shape of the world. The world model's simulation of the world's rotation, or lack thereof, produces the centrifugal acceleration component of gravity. The world model s reproduction of the world's shape will produce different positions relative to the world center for a given height above the surface. These differences produce variations in the gravitation component of gravity. This paper examines the actual performance of world and gravity/gravitation pairs in a simulation using the Earth.

Solution processed ZnO hybrid nanocomposite with tailored work function for improved electron transport layer in organic photovoltaic devices.

PubMed

Lee, Yun-Ju; Wang, Jian; Cheng, Samuel R; Hsu, Julia W P

2013-09-25

We demonstrate improved organic photovoltaic device performance using solution processed electron transport layers of ZnO nanoparticle (NP) films containing organic additives, poly(vinylpyrrolidone) (PVP), or diethanolamine (DEA), that do not require post processing after film deposition. Inclusion of PVP or DEA decreased the ZnO work function by 0.4 eV through interfacial dipole formation. While PVP did not change the ZnO NP shape or size, DEA modified the ZnO shape from 5 nm × 15 nm nanorods to 5 nm nanoparticles. At an optimized PVP concentration of 0.7 wt %, ZnO NP:PVP electron transport layers (ETLs) improved the efficiency of inverted P3HT:PCBM devices by 37%, primarily through higher fill factor. ZnO NP:PVP and ZnO NP:DEA ETLs increased the open circuit voltage of inverted P3HT:ICBA devices by 0.07 V due to decreasing ETL work function, leading to enhanced built-in field. The relationship between ZnO nanocomposite ETL work function, donor-acceptor energy offset, and device performance is discussed. The effects of the two additives are compared.

Optimization of the photoneutron target geometry for e-accelerator based BNCT

PubMed Central

Chegeni, Nahid; Pur, Saleh Boveiry; Razmjoo, Sasan; Hoseini, Seydeh Khadijed

2017-01-01

Background and aim Today, electron accelerators are taken into consideration as photoneutron sources. Therefore, for maximum production of epithermal neutron flux, designing a photoneutron target is of significant importance. In this paper, the effect of thickness and geometric shape of a photoneutron target on neutron output were investigated. Methods In this study, a pencil photon source with 13, 15, 18, 20 and 25 MeV energies and a diameter of 2 mm was investigated using Monte Carlo simulation method using MCNP code. To optimize the design of the photoneutron target, the tungsten target with various geometries and thicknesses was investigated. Results The maximum neutron flux produced for all target geometries and thicknesses occurred at neutron energy peak of around 0.46 MeV. As the thickness increased to 2 cm, neutron flux increased and then a decreasing trend was observed. For various geometrical shapes, the determining factor in photoneutron output was the effective target thickness in the photon interaction path that increased by the increase in the area of interaction. Another factor was the angle of the photon’s incidence with the target surface that resulted in a significant decrease in photoneutron output in cone-shaped targets Conclusion Three factors including the total neutron flux, neutrons energy spectrum, and convergence of neutrons plays an important role in the selection of geometry and shape of the target that should be investigated considering beam shaping assembly (BSA) shape. PMID:28848635

Shape coexistence and shape transition in light nuclei

NASA Astrophysics Data System (ADS)

Saxena, G.; Kumawat, M.; Singh, U. K.; Kaushik, M.; Jain, S. K.

2018-05-01

A systematic study has been performed to investigate the shape coexistence and shape transition for even-even nuclei between Z = 10-20 by employing Relativistic Mean-Filed plus BCS (RMF+BCS) approach. We calculate ground state properties viz. binding energy, deformation etc. for even-even nuclei to find the shape coexistence and shape transition. These results are found in agreement of recent experiments and consistent with other parameters of RMF and other theories.

Factors influencing hand/eye synchronicity in the computer age.

PubMed

Grant, A H

1992-09-01

In using a computer, the relation of vision to hand/finger actuated keyboard usage in performing fine motor-coordinated functions is influenced by the physical location, size, and collective placement of the keys. Traditional nonprehensile flat/rectangular keyboard applications usually require a high and nearly constant level of visual attention. Biometrically shaped keyboards would allow for prehensile hand-posturing, thus affording better tactile familiarity with the keys, requiring less intense and less constant level of visual attention to the task, and providing a greater measure of freedom from having to visualize the key(s). Workpace and related physiological changes, aging, onset of monocularization (intermittent lapsing of binocularity for near vision) that accompanies presbyopia, tool colors, and background contrast are factors affecting constancy of visual attention to task performance. Capitas extension, excessive excyclotorsion, and repetitive strain injuries (such as carpal tunnel syndrome) are common and debilitating concomitants to computer usage. These problems can be remedied by improved keyboard design. The salutary role of mnemonics in minimizing visual dependency is discussed.

Normalized stiffness ratios for mechanical characterization of isotropic acoustic foams.

PubMed

Sahraoui, Sohbi; Brouard, Bruno; Benyahia, Lazhar; Parmentier, Damien; Geslain, Alan

2013-12-01

This paper presents a method for the mechanical characterization of isotropic foams at low frequency. The objective of this study is to determine the Young's modulus, the Poisson's ratio, and the loss factor of commercially available foam plates. The method is applied on porous samples having square and circular sections. The main idea of this work is to perform quasi-static compression tests of a single foam sample followed by two juxtaposed samples having the same dimensions. The load and displacement measurements lead to a direct extraction of the elastic constants by means of normalized stiffness and normalized stiffness ratio which depend on Poisson's ratio and shape factor. The normalized stiffness is calculated by the finite element method for different Poisson ratios. The no-slip boundary conditions imposed by the loading rigid plates create interfaces with a complex strain distribution. Beforehand, compression tests were performed by means of a standard tensile machine in order to determine the appropriate pre-compression rate for quasi-static tests.

Validation of an interior noise prediction model for a composite cylinder

NASA Technical Reports Server (NTRS)

Beyer, Todd B.; Grosveld, Ferdinand W.

1987-01-01

An acoustic modal analysis has been performed in the cavity of a composite cylinder model of an aircraft fuselage. The filament wound, composite shell is 12 feet long and 5.5 feet in diameter. A one-half-in. thick plywood floor is attached to the shell 69 deg from the vertical centerline through the bottom of the shell. The acoustic modal frequencies were obtained from a sound pressure level and phase survey conducted throughout the interior volume bounded by the floor, endcaps and stiffened shell, while being excited by white noise from a loudspeaker source. The measured acoustic resonance frequencies and mode shapes compare well with analytical predictions from the Propeller Aircraft Interior Noise (PAIN) model. Details of the theory and derivation of the acoustic characteristics have been included. Reverberation time measurements, using the integrated impulse technique, have been performed to determine acoustic loss factors. These measured loss factors have been input to the PAIN program in order to more accurately predict the space-averaged interior noise of the composite cylinder.

Variety of geologic silhouette shapes distinguishable by multiple rotations method of quantitative shape analysis text

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

Collins, D.G.; Parks, J.M.

1984-04-01

Silhouette shapes are two-dimensional projections of three-dimensional objects such as sand grains, gravel, and fossils. Within-the-margin markings such as chamber boundaries, sutures, or ribs are ignored. Comparisons between populations of objects from similar and differential origins (i.e., environments, species or genera, growth series, etc) is aided by quantifying the shapes. The Multiple Rotations Method (MRM) uses a variation of ''eigenshapes'', which is capable of distinguishing most of the subtle variations that the ''trained eye'' can detect. With a video-digitizer and microcomputer, MRM is fast, more accurate, and more objective than the human eye. The resulting shape descriptors comprise 5 ormore » 6 numbers per object that can be stored and retrieved to compare with similar descriptions of other objects. The original-shape outlines can be reconstituted sufficiently for gross recognition from these few numerical descriptors. Thus, a semi-automated data-retrieval system becomes feasible, with silhouette-shape descriptions as one of several recognition criteria. MRM consists of four ''rotations'': rotation about a center to a comparable orientation; a principal-components rotation to reduce the many original shape descriptors to a few; a VARIMAX orthogonal-factor rotation to achieve simple structure; and a rotation to achieve factor scores on individual objects. A variety of subtly different shapes includes sand grains from several locations, ages, and environments, and fossils of several types. This variety illustrates the feasibility of quantitative comparisons by MRM.« less

Dark Matter characterization at the LHC in the Effective Field Theory approach

NASA Astrophysics Data System (ADS)

Belyaev, Alexander; Panizzi, Luca; Pukhov, Alexander; Thomas, Marc

2017-04-01

We have studied the complete set of dimension 5 and dimension 6 effective operators involving the interaction of scalar, fermion and vector Dark Matter (DM) with SM quarks and gluons, to explore the possibility to distinguish these operators and characterise the spin of DM at the LHC. We have found that three factors — the effective dimension of the operator, the structure of the SM part of the operator and the parton densities of the SM particles connected to the operator — uniquely define the shape of the (unobservable) invariant mass distribution of the DM pair and, consequently, the shape of the (observable) E T miss distribution related to it. Using χ2 analysis, we found that at the LHC, with a luminosity of 300 fb-1, certain classes of EFT operators can be distinguished from each other. Hence, since DM spin is partly correlated with the factors defining the shape of E T miss , the LHC can potentially shed a light also on DM spin. We have also observed a drastic difference in the efficiencies (up to two orders of magnitude) for large E T miss cuts scenarios with different DM spin, thus indicating that the DM discovery potential strongly depends on it. The study we perform here can be applied more generally than within the EFT paradigm, where the DM mediator is not produced on-the-mass-shell, such as the case of t-channel mediator or mediator with mass below 2 M DM, where the invariant mass of the DM pair is not fixed.

The effect of texture on the shaft surface on the sealing performance of radial lip seals

NASA Astrophysics Data System (ADS)

Guo, Fei; Jia, XiaoHong; Gao, Zhi; Wang, YuMing

2014-07-01

On the basis of elastohydrodynamic model, the present study numerically analyzes the effect of various microdimple texture shapes, namely, circular, square, oriented isosceles triangular, on the pumping rate and the friction torque of radial lip seals, and determines the microdimple texture shape that can produce positive pumping rate. The area ratio, depth and shape dimension of a single texture are the most important geometric parameters which influence the tribological performance. According to the selected texture shape, parameter analysis is conducted to determine the optimal combination for the above three parameters. Simultaneously, the simulated performances of radial lip seal with texture on the shaft surface are compared with those of the conventional lip seal without any texture on the shaft surface.

Particle Shape and Composition of NU-LHT-2M

NASA Technical Reports Server (NTRS)

Rickman, D. L.; Lowers, H.

2012-01-01

Particle shapes of the lunar regolith simulant NU-LHT-2M were analyzed by scanning electron microscope of polished sections. These data provide shape, size, and composition information on a particle by particle basis. 5,193 particles were measured, divided into four sized fractions: less than 200 mesh, 200-100 mesh, 100-35 mesh, and greater than 35 mesh. 99.2% of all particles were monominerallic. Minor size versus composition effects were noted in minor and trace mineralogy. The two metrics used are aspect ratio and Heywood factor, plotted as normalized frequency distributions. Shape versus composition effects were noted for glass and possibly chlorite. To aid in analysis, the measured shape distributions are compared to data for ellipses and rectangles. Several other simple geometric shapes are also investigated as to how they plot in aspect ratio versus Heywood factor space. The bulk of the data previously reported, which were acquired in a plane of projection, are between the ellipse and rectangle lines. In contrast, these data, which were acquired in a plane of section, clearly show that a significant number of particles have concave hulls in this view. Appendices cover details of measurement error, use of geometric shapes for comparative analysis, and a logic for comparing data from plane of projection and plane of section measurements.

Characterization of wood dust from furniture by scanning electron microscopy and energy-dispersive x-ray analysis.

PubMed

Gómez Yepes, Milena Elizabeth; Cremades, Lázaro V

2011-01-01

Study characterized and analyzed form factor, elementary composition and particle size of wood dust, in order to understand its harmful health effects on carpenters in Quindío (Colombia). Once particle characteristics (size distributions, aerodynamic equivalent diameter (D(α)), elemental composition and shape factors) were analyzed, particles were then characterized via scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray analysis (EDXRA). SEM analysis of particulate matter showed: 1) cone-shaped particle ranged from 2.09 to 48.79 µm D(α); 2) rectangular prism-shaped particle from 2.47 to 72.9 µm D(α); 3) cylindrically-shaped particle from 2.5 to 48.79 µm D(α); and 4) spherically-shaped particle from 2.61 to 51.93 µm D(α). EDXRA reveals presence of chemical elements from paints and varnishes such as Ca, K, Na and Cr. SEM/EDXRA contributes in a significant manner to the morphological characterization of wood dust. It is obvious that the type of particles sampled is a complex function of shapes and sizes of particles. Thus, it is important to investigate the influence of particles characteristics, morphology, shapes and D(α) that may affect the health of carpenters in Quindío.

Method of multivariate spectral analysis

DOEpatents

Keenan, Michael R.; Kotula, Paul G.

2004-01-06

A method of determining the properties of a sample from measured spectral data collected from the sample by performing a multivariate spectral analysis. The method can include: generating a two-dimensional matrix A containing measured spectral data; providing a weighted spectral data matrix D by performing a weighting operation on matrix A; factoring D into the product of two matrices, C and S.sup.T, by performing a constrained alternating least-squares analysis of D=CS.sup.T, where C is a concentration intensity matrix and S is a spectral shapes matrix; unweighting C and S by applying the inverse of the weighting used previously; and determining the properties of the sample by inspecting C and S. This method can be used to analyze X-ray spectral data generated by operating a Scanning Electron Microscope (SEM) with an attached Energy Dispersive Spectrometer (EDS).

Aesthetic breast shape preferences among plastic surgeons.

PubMed

Broer, Peter Niclas; Juran, Sabrina; Walker, Marc E; Ng, Reuben; Weichman, Katie; Tanna, Neil; Liu, Yuen-Jong; Shah, Ajul; Patel, Anup; Persing, John A; Thomson, James Grant

2015-06-01

There has been little discussion in the plastic surgery literature regarding breast shape preferences among plastic surgeons, despite strong evidence that such aesthetic preferences are influenced by multiple factors. Much effort has been focused on delineating the objective criteria by which an "attractive" breast might be defined. This study aimed at providing a better understanding of the presence and significance of differences in personal aesthetic perception, and how these relate to a plastic surgeon's demographic, ethnic, and cultural background, as well as practice type (academic vs private). An interactive online survey was designed. Modifiable ranges of upper pole fullness and areola size were achieved via digital alteration, enabling participants to interactively change the shape of a model's breasts. The questionnaire was translated into multiple languages and sent to plastic surgeons worldwide. Demographic data were also collected. Analysis of variance was used to elucidate plastic surgeon's breast shape preferences in respect to sex and age, geographic and ethnic background, as well as practice type. The authors gathered 614 responses from 29 different countries. Significant differences regarding preferences for upper pole fullness, areola size in the natural breast, and areola size in the augmented breast were identified across surgeons from the different countries. Further, significant relationships regarding breast shape preferences were distilled between the age and sex of the surgeon, as well as the practice type. No differences were found in respect to the surgeons' self-reported ethnic background. Country of residence, age, and practice type significantly impact breast shape preferences of plastic surgeons. These findings have implications for both patients seeking and surgeons performing cosmetic and reconstructive breast surgery. In an increasingly global environment, cultural differences and international variability must be considered when defining and publishing new techniques and aesthetic outcomes. When both the plastic surgeon and the patient are able to adequately and effectively communicate their preferences regarding the shape and relations of the breast, they will be more successful at achieving satisfying results.

Detection of Single Standing Dead Trees from Aerial Color Infrared Imagery by Segmentation with Shape and Intensity Priors

NASA Astrophysics Data System (ADS)

Polewski, P.; Yao, W.; Heurich, M.; Krzystek, P.; Stilla, U.

2015-03-01

Standing dead trees, known as snags, are an essential factor in maintaining biodiversity in forest ecosystems. Combined with their role as carbon sinks, this makes for a compelling reason to study their spatial distribution. This paper presents an integrated method to detect and delineate individual dead tree crowns from color infrared aerial imagery. Our approach consists of two steps which incorporate statistical information about prior distributions of both the image intensities and the shapes of the target objects. In the first step, we perform a Gaussian Mixture Model clustering in the pixel color space with priors on the cluster means, obtaining up to 3 components corresponding to dead trees, living trees, and shadows. We then refine the dead tree regions using a level set segmentation method enriched with a generative model of the dead trees' shape distribution as well as a discriminative model of their pixel intensity distribution. The iterative application of the statistical shape template yields the set of delineated dead crowns. The prior information enforces the consistency of the template's shape variation with the shape manifold defined by manually labeled training examples, which makes it possible to separate crowns located in close proximity and prevents the formation of large crown clusters. Also, the statistical information built into the segmentation gives rise to an implicit detection scheme, because the shape template evolves towards an empty contour if not enough evidence for the object is present in the image. We test our method on 3 sample plots from the Bavarian Forest National Park with reference data obtained by manually marking individual dead tree polygons in the images. Our results are scenario-dependent and range from a correctness/completeness of 0.71/0.81 up to 0.77/1, with an average center-of-gravity displacement of 3-5 pixels between the detected and reference polygons.

Quantitative Understanding of SHAPE Mechanism from RNA Structure and Dynamics Analysis.

PubMed

Hurst, Travis; Xu, Xiaojun; Zhao, Peinan; Chen, Shi-Jie

2018-05-10

The selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) method probes RNA local structural and dynamic information at single nucleotide resolution. To gain quantitative insights into the relationship between nucleotide flexibility, RNA 3D structure, and SHAPE reactivity, we develop a 3D Structure-SHAPE Relationship model (3DSSR) to rebuild SHAPE profiles from 3D structures. The model starts from RNA structures and combines nucleotide interaction strength and conformational propensity, ligand (SHAPE reagent) accessibility, and base-pairing pattern through a composite function to quantify the correlation between SHAPE reactivity and nucleotide conformational stability. The 3DSSR model shows the relationship between SHAPE reactivity and RNA structure and energetics. Comparisons between the 3DSSR-predicted SHAPE profile and the experimental SHAPE data show correlation, suggesting that the extracted analytical function may have captured the key factors that determine the SHAPE reactivity profile. Furthermore, the theory offers an effective method to sieve RNA 3D models and exclude models that are incompatible with experimental SHAPE data.

Study on the effects of flow in the volute casing on the performance of a sirocco fan

NASA Astrophysics Data System (ADS)

Adachi, Tsutomu; Sugita, Naohiro; Ohomori, Satoshi

2004-08-01

The flow at the exit from the runner blade of a centrifugal fan with forward curved blades (a sirocco fan) sometimes separates and becomes unstable. We have conducted many researches on the impeller shape of a sirocco fan, proper inlet and exit blade angles were considered to obtain optimum performance. In this paper, the casing shape were decided by changing the circumferential angle, magnifying angle and the width, 21 sorts of casings were used. Performance tests, inner flow velocity and pressure distributions were measured as well. Computational fluid dynamic calculations were also made and compared with the experimental results. Finally, the most suitable casing shape for best performance is considered.

Performance Simulation of a Flat-Plate Thermoelectric Module Consisting of Square Truncated Pyramid Elements

NASA Astrophysics Data System (ADS)

Oki, Sae; Suzuki, Ryosuke O.

2017-05-01

The performance of a flat-plate thermoelectric (TE) module consisting of square truncated pyramid elements is simulated using commercial software and original TE programs. Assuming that the temperatures of both the hot and cold surfaces are constant, the performance can be varied by changing the element shape and element alignment pattern. When the angle between the edge and the base is 85° and the small square surfaces of all n-type element faces are connected to the low-temperature surface, the efficiency becomes the largest among all the 17 examined shapes and patterns. By changing the shape to match the temperature distribution, the performance of the TE module is maximized.

Human factors in mental healthcare: A work system analysis of a community-based program for older adults with depression and dementia.

PubMed

Heiden, Siobhan M; Holden, Richard J; Alder, Catherine A; Bodke, Kunal; Boustani, Malaz

2017-10-01

Mental healthcare is a critical but largely unexplored application domain for human factors/ergonomics. This paper reports on a work system evaluation of a home-based dementia and depression care program for older adults, the Aging Brain Care program. The Workflow Elements Model was used to guide data collection and analysis of 59 h of observation, supplemented by key informant input. We identified four actors, 37 artifacts across seven types, ten action categories, and ten outcomes including improved health and safety. Five themes emerged regarding barriers and facilitators to care delivery in the program: the centrality of relationship building; the use of adaptive workarounds; performance of duplicate work; travel and scheduling challenges; and communication-related factors. Findings offer new insight into how mental healthcare services are delivered in a community-based program and key work-related factors shaping program outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cell-based delivery of glucagon-like peptide-1 using encapsulated mesenchymal stem cells.

PubMed

Wallrapp, Christine; Thoenes, Eric; Thürmer, Frank; Jork, Anette; Kassem, Moustapha; Geigle, Peter

2013-01-01

Glucagon-like peptide-1 (GLP-1) CellBeads are cell-based implants for the sustained local delivery of bioactive factors. They consist of GLP-1 secreting mesenchymal stem cells encapsulated in a spherically shaped immuno-isolating alginate matrix. A highly standardized and reproducible encapsulation method is described for the manufacturing of homogeneous CellBeads. Viability and sustained secretion was shown for the recombinant GLP-1 and the cell endogenous bioactive factors like vascular endothelial growth factor, neurotrophin 3 (NT-3) and glial cell line-derived neurotrophic factor. Manufacturing and quality control is performed in compliance with good manufacturing practice and fulfils all regulatory requirements for human clinical use. GLP-1 CellBeads combine the neuro- and cardioprotective properties of both GLP-1 and mesenchymal stem cells. First promising results were obtained from preclinical studies and an ongoing safety trial in humans but further studies have to prove the overall potential of CellBead technology in cell-based regenerative medicine.

Optimal design application on the advanced aeroelastic rotor blade

NASA Technical Reports Server (NTRS)

Wei, F. S.; Jones, R.

1985-01-01

The vibration and performance optimization procedure using regression analysis was successfully applied to an advanced aeroelastic blade design study. The major advantage of this regression technique is that multiple optimizations can be performed to evaluate the effects of various objective functions and constraint functions. The data bases obtained from the rotorcraft flight simulation program C81 and Myklestad mode shape program are analytically determined as a function of each design variable. This approach has been verified for various blade radial ballast weight locations and blade planforms. This method can also be utilized to ascertain the effect of a particular cost function which is composed of several objective functions with different weighting factors for various mission requirements without any additional effort.

Psychometric Evaluation of the Eating Disorder Examination-Questionnaire for Bariatric Surgery Candidates

PubMed Central

Hrabosky, Joshua I.; White, Marney A.; Masheb, Robin M.; Rothschild, Bruce S.; Burke-Martindale, Carolyn H.; Grilo, Carlos M.

2013-01-01

Objective Despite increasing use of the Eating Disorder Examination-Questionnaire (EDE-Q) in bariatric surgery patients, little is known about the utility and psychometric performance of this self-report measure in this clinical group. The primary purpose of the current study was to evaluate the factor structure and construct validity of the EDE-Q in a large series of bariatric surgery candidates. Methods and Procedures Participants were 337 obese bariatric surgery candidates. Participants completed the EDE-Q and a battery of behavioral and psychological measures. Results Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) produced a 12-item, 4-factor structure of the EDE-Q. The four factors, interpreted as Dietary Restraint, Eating Disturbance, Appearance Concerns, and Shape/Weight Overvaluation, were found to be internally consistent and converged with other relevant measures of psychopathology. Discussion Factor analysis of the EDE-Q in bariatric surgery candidates did not replicate the original subscales but revealed an alternative factor structure. Future research must further evaluate the psychometric properties, including the factor structure, of the EDE-Q in this and other diverse populations and consider means of improving this measure's ability to best assess eating-related pathology in bariatric surgery patients. PMID:18379561

Shape and mechanics in thalattosuchian (Crocodylomorpha) skulls: implications for feeding behaviour and niche partitioning

PubMed Central

Pierce, S E; Angielczyk, K D; Rayfield, E J

2009-01-01

Variation in modern crocodilian and extinct thalattosuchian crocodylomorph skull morphology is only weakly correlated with phylogeny, implying that factors other than evolutionary proximity play important roles in determining crocodile skull shape. To further explore factors potentially influencing morphological differentiation within the Thalattosuchia, we examine teleosaurid and metriorhynchid skull shape variation within a mechanical and dietary context using a combination of finite element modelling and multivariate statistics. Patterns of stress distribution through the skull were found to be very similar in teleosaurid and metriorhynchid species, with stress peaking at the posterior constriction of the snout and around the enlarged supratemporal fenestrae. However, the magnitudes of stresses differ, with metriorhynchids having generally stronger skulls. As with modern crocodilians, a strong linear relationship between skull length and skull strength exists, with short-snouted morphotypes experiencing less stress through the skull than long-snouted morphotypes under equivalent loads. Selection on snout shape related to dietary preference was found to work in orthogonal directions in the two families: diet is associated with snout length in teleosaurids and with snout width in metriorhynchids, suggesting that teleosaurid skulls were adapted for speed of attack and metriorhynchid skulls for force production. Evidence also indicates that morphological and functional differentiation of the skull occurred as a result of dietary preference, allowing closely related sympatric species to exploit a limited environment. Comparisons of the mechanical performance of the thalattosuchian skull with extant crocodilians show that teleosaurids and long-snouted metriorhynchids exhibit stress magnitudes similar to or greater than those of long-snouted modern forms, whereas short-snouted metriorhynchids display stress magnitudes converging on those found in short-snouted modern species. As a result, teleosaurids and long-snouted metriorhynchids were probably restricted to lateral attacks of the head and neck, but short-snouted metriorhynchids may have been able to employ the grasp and shake and/or ‘death roll’ feeding and foraging behaviours. PMID:19702868

Dynamic Magnification Factor in a Box-Shape Steel Girder

NASA Astrophysics Data System (ADS)

Rahbar-Ranji, A.

2014-01-01

The dynamic effect of moving loads on structures is treated as a dynamic magnification factor when resonant is not imminent. Studies have shown that the calculated magnification factors from field measurements could be higher than the values specified in design codes. It is the main aim of present paper to investigate the applicability and accuracy of a rule-based expression for calculation of dynamic magnification factor for lifting appliances used in marine industry. A steel box shape girder of a crane is considered and transient dynamic analysis using computer code ANSYS is implemented. Dynamic magnification factor is calculated for different loading conditions and compared with rule-based equation. The effects of lifting speeds, acceleration, damping ratio and position of cargo are examined. It is found that rule-based expression underestimate dynamic magnification factor.

Strategic design and fabrication of acrylic shape memory polymers

NASA Astrophysics Data System (ADS)

Park, Ju Hyuk; Kim, Hansu; Ryoun Youn, Jae; Song, Young Seok

2017-08-01

Modulation of thermomechanics nature is a critical issue for an optimized use of shape memory polymers (SMPs). In this study, a strategic approach was proposed to control the transition temperature of SMPs. Free radical vinyl polymerization was employed for tailoring and preparing acrylic SMPs. Transition temperatures of the shape memory tri-copolymers were tuned by changing the composition of monomers. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses were carried out to evaluate the chemical structures and compositions of the synthesized SMPs. The thermomechanical properties and shape memory performance of the SMPs were also examined by performing dynamic mechanical thermal analysis. Numerical simulation based on a finite element method provided consistent results with experimental cyclic shape memory tests of the specimens. Transient shape recovery tests were conducted and optical transparence of the samples was identified. We envision that the materials proposed in this study can help develop a new type of shape-memory devices in biomedical and aerospace engineering applications.

Fiber optic shape sensing for monitoring of flexible structures

NASA Astrophysics Data System (ADS)

Lally, Evan M.; Reaves, Matt; Horrell, Emily; Klute, Sandra; Froggatt, Mark E.

2012-04-01

Recent advances in materials science have resulted in a proliferation of flexible structures for high-performance civil, mechanical, and aerospace applications. Large aspect-ratio aircraft wings, composite wind turbine blades, and suspension bridges are all designed to meet critical performance targets while adapting to dynamic loading conditions. By monitoring the distributed shape of a flexible component, fiber optic shape sensing technology has the potential to provide valuable data during design, testing, and operation of these smart structures. This work presents a demonstration of such an extended-range fiber optic shape sensing technology. Three-dimensional distributed shape and position sensing is demonstrated over a 30m length using a monolithic silica fiber with multiple optical cores. A novel, helicallywound geometry endows the fiber with the capability to convert distributed strain measurements, made using Optical Frequency-Domain Reflectometry (OFDR), to a measurement of curvature, twist, and 3D shape along its entire length. Laboratory testing of the extended-range shape sensing technology shows

Context-dependent planktivory: interacting effects of turbidity and predation risk on adaptive foraging

USGS Publications Warehouse

Pangle, Kevin L.; Malinich, Timothy D.; Bunnell, David B.; DeVries, Dennis R.; Ludsin, Stuart A.

2012-01-01

By shaping species interactions, adaptive phenotypic plasticity can profoundly influence ecosystems. Predicting such outcomes has proven difficult, however, owing in part to the dependence of plasticity on the environmental context. Of particular relevance are environmental factors that affect sensory performance in organisms in ways that alter the tradeoffs associated with adaptive phenotypic responses. We explored the influence of turbidity, which simultaneously and differentially affects the sensory performance of consumers at multiple trophic levels, on the indirect effect of a top predator (piscivorous fish) on a basal prey resource (zooplankton) that is mediated through changes in the plastic foraging behavior of an intermediate consumer (zooplanktivorous fish). We first generated theoretical predictions of the adaptive foraging response of a zooplanktivore across wide gradients of turbidity and predation risk by a piscivore. Our model predicted that predation risk can change the negative relationship between intermediate consumer foraging and turbidity into a humped-shaped (unimodal) one in which foraging is low in both clear and highly turbid conditions due to foraging-related risk and visual constraints, respectively. Consequently, the positive trait-mediated indirect effect (TMIE) of the top predator on the basal resource is predicted to peak at low turbidity and decline thereafter until it reaches an asymptote of zero at intermediate turbidity levels (when foraging equals that which is predicted when the top predator is absent). We used field observations and a laboratory experiment to test our model predictions. In support, we found humped-shaped relationships between planktivory and turbidity for several zooplanktivorous fishes from diverse freshwater ecosystems with predation risk. Further, our experiment demonstrated that predation risk reduced zooplanktivory by yellow perch (Perca flavescens) at a low turbidity, but had no effect on consumption at an intermediate turbidity. Together, our theoretical and empirical findings show how the environmental context can govern the strength of TMIEs by influencing consumer sensory performance and how these effects can become realized in nature over wide environmental gradients. Additionally, our hump-shaped foraging curve represents an important departure from the conventional view of turbidity's effect on planktivorous fishes, thus potentially requiring a reconceptualization of turbidity's impact on aquatic food-web interactions.

Influence of strut cross-section of stents on local hemodynamics in stented arteries

NASA Astrophysics Data System (ADS)

Jiang, Yongfei; Zhang, Jun; Zhao, Wanhua

2016-05-01

Stenting is a very effective treatment for stenotic vascular diseases, but vascular geometries altered by stent implantation may lead to flow disturbances which play an important role in the initiation and progression of restenosis, especially in the near wall in stented arterial regions. So stent designs have become one of the indispensable factors needed to be considered for reducing the flow disturbances. In this paper, the structural designs of strut cross-section are considered as an aspect of stent designs to be studied in details. Six virtual stents with different strut cross-section are designed for deployments in the same ideal arterial model. Computational fluid dynamics (CFD) methods are performed to study how the shape and the aspect ratio (AR) of strut cross-section modified the local hemodynamics in the stented segments. The results indicate that stents with different strut cross-sections have different influence on the hemodynamics. Stents with streamlined cross-sectional struts for circular arc or elliptical arc can significantly enhance wall shear stress (WSS) in the stented segments, and reduce the flow disturbances around stent struts. The performances of stents with streamlined cross-sectional struts are better than that of stents with non-streamlined cross-sectional struts for rectangle. The results also show that stents with a larger AR cross-section are more conductive to improve the blood flow. The present study provides an understanding of the flow physics in the vicinity of stent struts and indicates that the shape and AR of strut cross-section ought to be considered as important factors to minimize flow disturbance in stent designs.

Progress in extremely high brightness LED-based light sources

NASA Astrophysics Data System (ADS)

Hoelen, Christoph; Antonis, Piet; de Boer, Dick; Koole, Rolf; Kadijk, Simon; Li, Yun; Vanbroekhoven, Vincent; Van De Voorde, Patrick

2017-09-01

Although the maximum brightness of LEDs has been increasing continuously during the past decade, their luminance is still far from what is required for multiple applications that still rely on the high brightness of discharge lamps. In particular for high brightness applications with limited étendue, e.g. front projection, only very modest luminance values in the beam can be achieved with LEDs compared to systems based on discharge lamps or lasers. With dedicated architectures, phosphor-converted green LEDs for projection may achieve luminance values up to 200-300 Mnit. In this paper we report on the progress made in the development of light engines based on an elongated luminescent concentrator pumped by blue LEDs. This concept has recently been introduced to the market as ColorSpark High Lumen Density LED technology. These sources outperform the maximum brightness of LEDs by multiple factors. In LED front projection, green LEDs are the main limiting factor. With our green modules, we now have achieved peak luminance values of 2 Gnit, enabling LED-based projection systems with over 4000 ANSI lm. Extension of this concept to yellow and red light sources is presented. The light source efficiency has been increased considerably, reaching 45-60 lm/W for green under practical application conditions. The module architecture, beam shaping, and performance characteristics are reviewed, as well as system aspects. The performance increase, spectral range extensions, beam-shaping flexibility, and cost reductions realized with the new module architecture enable a breakthrough in LED-based projection systems and in a wide variety of other high brightness applications.

Reconstruction method for running shape of rotor blade considering nonlinear stiffness and loads

NASA Astrophysics Data System (ADS)

Wang, Yongliang; Kang, Da; Zhong, Jingjun

2017-10-01

The aerodynamic and centrifugal loads acting on the rotating blade make the blade configuration deformed comparing to its shape at rest. Accurate prediction of the running blade configuration plays a significant role in examining and analyzing turbomachinery performance. Considering nonlinear stiffness and loads, a reconstruction method is presented to address transformation of a rotating blade from cold to hot state. When calculating blade deformations, the blade stiffness and load conditions are updated simultaneously as blade shape varies. The reconstruction procedure is iterated till a converged hot blade shape is obtained. This method has been employed to determine the operating blade shapes of a test rotor blade and the Stage 37 rotor blade. The calculated results are compared with the experiments. The results show that the proposed method used for blade operating shape prediction is effective. The studies also show that this method can improve precision of finite element analysis and aerodynamic performance analysis.

Undue influence of weight and shape: is it distinct from body dissatisfaction and concern about weight and shape?

PubMed

Wade, T D; Zhu, G; Martin, N G

2011-04-01

Three cognitive constructs are risk factors for eating disorders: undue influence of weight and shape, concern about weight and shape, and body dissatisfaction (BD). Undue influence, a diagnostic criterion for eating disorders, is postulated to be closely associated with self-esteem whereas BD is postulated to be closely associated with body mass index (BMI). We understand less about the relationships with concern about weight and shape. The aim of the current investigation was examine the degree of overlap across these five phenotypes in terms of latent genetic and environmental risk factors in order to draw some conclusions about the similarities and differences across the three cognitive variables. A sample of female Australian twins (n=1056, including 348 complete pairs), mean age 35 years (S.D.=2.11, range 28-40), completed a semi-structured interview about eating pathology and self-report questionnaires. An independent pathways model was used to investigate the overlap of genetic and environmental risk factors for the five phenotypes. In terms of variance that was not shared with other phenotypes, self-esteem emerged as being separate, with 100% of its variance unshared with the other phenotypes, followed by undue influence (51%) and then concern (34%), BD (28%) and BMI (32%). In terms of shared genetic risk, undue influence and concern were more closely related than BD, whereas BMI and BD were found to share common sources of risk. With respect to environmental risk factors, concern, BMI and BD were more closely related to each other than to undue influence.

Impact of Contextual Factors and Substance Characteristics on Perspectives toward Cognitive Enhancement

PubMed Central

Sattler, Sebastian; Forlini, Cynthia; Racine, Éric; Sauer, Carsten

2013-01-01

Enhancing cognitive performance with substances–especially prescription drugs–is a fiercely debated topic among scholars and in the media. The empirical basis for these discussions is limited, given that the actual nature of factors that influence the acceptability of and willingness to use cognitive enhancement substances remains unclear. In an online factorial survey, contextual and substance-specific characteristics of substances that improve academic performance were varied experimentally and presented to respondents. Students in four German universities rated their willingness to use and moral acceptance of different substances for cognitive enhancement. We found that the overall willingness to use performance enhancing substances is low. Most respondents considered the use of these substances as morally unacceptable. Situational influences such as peer pressure, policies concerning substance use, relative performance level of peers, but also characteristics of the substance, such as perceptions of substance safety, shape the willingness and acceptability of using a substance to enhance academic performance. Among the findings is evidence of a contagion effect meaning that the willingness was higher when the respondents have more CE drug users in their social network. We also found deterrence effects from strong side effects of using the substance, as well as from policy regulations and sanctions. Regulations might activate social norms against usage and sanctions can be seen as costly to users. Moreover, enhancement substances seem to be most tempting to low performers to catch up with others compared to high performers. By identifying contextual factors and substance characteristics influencing the willingness and acceptability of cognitive enhancers, policy approaches could consider these insights to better manage the use of such substances. PMID:23940757

Stereoscopic shape discrimination is well preserved across changes in object size.

PubMed

Norman, J Farley; Swindle, Jessica M; Jennings, L RaShae; Mullins, Elizabeth M; Beers, Amanda M

2009-06-01

A single experiment evaluated human observers' ability to discriminate the shape of solid objects that varied in size and orientation in depth. The object shapes were defined by binocular disparity, Lambertian shading, and texture. The object surfaces were smoothly curved and had naturalistic shapes, resembling those of water-smoothed granite rocks. On any given trial, two objects were presented that were either the same or different in terms of shape. When the "same" objects were presented, they differed in their orientation in depth by 25 degrees , 45 degrees , or 65 degrees . The observers were required to judge whether any given pair of objects was the "same" or "different" in terms of shape. The size of the objects was also varied by amounts up to +/-40% relative to the standard size. The observers' shape discrimination performance was strongly affected by the magnitude of the orientation changes in depth - thus, their performance was viewpoint dependent. In contrast, the observers' shape discrimination abilities were only slightly affected by changes in the overall size of the objects. It appears that human observers can recognize the three-dimensional shape of objects in a manner that is relatively independent of size.

Falling Victim to Wasps in the Air: A Fate Driven by Prey Flight Morphology?

PubMed Central

Ballesteros, Yolanda; Polidori, Carlo; Tormos, José; Baños-Picón, Laura; Asís, Josep D.

2016-01-01

In prey-predator systems where the interacting individuals are both fliers, the flight performance of both participants heavily influences the probability of success of the predator (the prey is captured) and of the prey (the predator is avoided). While the flight morphology (an estimate of flight performance) of predatory wasps has rarely been addressed as a factor that may contribute to explain prey use, how the flight morphology of potential prey influences the output of predator-prey encounters has not been studied. Here, we hypothesized that flight morphology associated with flight ability (flight muscle mass to body mass ratio (FMR) and body mass to wing area ratio (wing loading, WL)) of Diptera affect their probability of being captured by specialized Diptera-hunting wasps (Bembix merceti and B. zonata), predicting a better manoeuvrability and acceleration capacity achieved by higher FMR and lower WL, and flight speed achieved by higher WL. In addition, wasp species with better flight morphology should be less limited by an advantageous Diptera flight morphology. Overall, the abundance of dipterans in the environment explained an important part of the observed variance in prey capture rate. However, it was not the only factor shaping prey capture. First, higher prey abundance was associated with greater capture rate for one species (B. merceti), although not for the other one. Second, the interaction observed between the environmental dipteran availability and dipteran WL for B. zonata suggests that greater dipteran WL (this probably meaning high cruising speed) decreased the probability of being captured, as long as fly abundance was high in the environment. Third, greater dipteran FMR (which likely means high manoeuvrability and acceleration capacity) helped to reduce predation by B. merceti if, again, dipterans were abundant in the environment. Wasp WL only varied with body mass but not between species, thereby hardly accounting for inter-specific differences in the wasps’ predatory patterns. However, the greater FMR of B. zonata, which implies better flight performance and greater load-lifting capacity, may explain why the capture rate in the two wasp species is affected by different factor interactions. In conclusion, although prey availability remains the primary factor shaping prey use, prey flight morphology seems to gain an additional role under conditions of abundant prey, when wasps can avoid flies with better flight ability. PMID:27046238

On the necessity of U-shaped learning.

PubMed

Carlucci, Lorenzo; Case, John

2013-01-01

A U-shaped curve in a cognitive-developmental trajectory refers to a three-step process: good performance followed by bad performance followed by good performance once again. U-shaped curves have been observed in a wide variety of cognitive-developmental and learning contexts. U-shaped learning seems to contradict the idea that learning is a monotonic, cumulative process and thus constitutes a challenge for competing theories of cognitive development and learning. U-shaped behavior in language learning (in particular in learning English past tense) has become a central topic in the Cognitive Science debate about learning models. Antagonist models (e.g., connectionism versus nativism) are often judged on their ability of modeling or accounting for U-shaped behavior. The prior literature is mostly occupied with explaining how U-shaped behavior occurs. Instead, we are interested in the necessity of this kind of apparently inefficient strategy. We present and discuss a body of results in the abstract mathematical setting of (extensions of) Gold-style computational learning theory addressing a mathematically precise version of the following question: Are there learning tasks that require U-shaped behavior? All notions considered are learning in the limit from positive data. We present results about the necessity of U-shaped learning in classical models of learning as well as in models with bounds on the memory of the learner. The pattern emerges that, for parameterized, cognitively relevant learning criteria, beyond very few initial parameter values, U-shapes are necessary for full learning power! We discuss the possible relevance of the above results for the Cognitive Science debate about learning models as well as directions for future research. Copyright © 2013 Cognitive Science Society, Inc.

3D shape representation with spatial probabilistic distribution of intrinsic shape keypoints

NASA Astrophysics Data System (ADS)

Ghorpade, Vijaya K.; Checchin, Paul; Malaterre, Laurent; Trassoudaine, Laurent

2017-12-01

The accelerated advancement in modeling, digitizing, and visualizing techniques for 3D shapes has led to an increasing amount of 3D models creation and usage, thanks to the 3D sensors which are readily available and easy to utilize. As a result, determining the similarity between 3D shapes has become consequential and is a fundamental task in shape-based recognition, retrieval, clustering, and classification. Several decades of research in Content-Based Information Retrieval (CBIR) has resulted in diverse techniques for 2D and 3D shape or object classification/retrieval and many benchmark data sets. In this article, a novel technique for 3D shape representation and object classification has been proposed based on analyses of spatial, geometric distributions of 3D keypoints. These distributions capture the intrinsic geometric structure of 3D objects. The result of the approach is a probability distribution function (PDF) produced from spatial disposition of 3D keypoints, keypoints which are stable on object surface and invariant to pose changes. Each class/instance of an object can be uniquely represented by a PDF. This shape representation is robust yet with a simple idea, easy to implement but fast enough to compute. Both Euclidean and topological space on object's surface are considered to build the PDFs. Topology-based geodesic distances between keypoints exploit the non-planar surface properties of the object. The performance of the novel shape signature is tested with object classification accuracy. The classification efficacy of the new shape analysis method is evaluated on a new dataset acquired with a Time-of-Flight camera, and also, a comparative evaluation on a standard benchmark dataset with state-of-the-art methods is performed. Experimental results demonstrate superior classification performance of the new approach on RGB-D dataset and depth data.

Collaborative Investigations of Shallow Water Optics Problems

DTIC Science & Technology

2004-12-01

Appendix E. Reprint of Radiative transfer equation inversion: Theory and shape factor models for retrieval of oceanic inherent optical properties, by F ...4829-4834. 5 Hoge, F . E., P. E. Lyon, C. D. Mobley, and L. K. Sundman, 2003. Radiative transfer equation inversion: Theory and shape factor models for...multilinear regression algorithms for the inversion of synthetic ocean colour spectra,, Int. J. Remote Sensing, 25(21), 4829-4834. Hoge, F . E., P. E. Lyon

Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

NASA Astrophysics Data System (ADS)

Philippe, F.; Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Villette, B.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.; Michel, P.; Frenje, J.; Gatu-Johnson, M.; Li, C. K.; Petrasso, R.; Glebov, V.; Sorce, C.; Stoeckl, C.; Nikroo, A.; Giraldez, E.

2014-07-01

A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

Optimization of entry-vehicle shapes during conceptual design

NASA Astrophysics Data System (ADS)

Dirkx, D.; Mooij, E.

2014-01-01

During the conceptual design of a re-entry vehicle, the vehicle shape and geometry can be varied and its impact on performance can be evaluated. In this study, the shape optimization of two classes of vehicles has been studied: a capsule and a winged vehicle. Their aerodynamic characteristics were analyzed using local-inclination methods, automatically selected per vehicle segment. Entry trajectories down to Mach 3 were calculated assuming trimmed conditions. For the winged vehicle, which has both a body flap and elevons, a guidance algorithm to track a reference heat-rate was used. Multi-objective particle swarm optimization was used to optimize the shape using objectives related to mass, volume and range. The optimizations show a large variation in vehicle performance over the explored parameter space. Areas of very strong non-linearity are observed in the direct neighborhood of the two-dimensional Pareto fronts. This indicates the need for robust exploration of the influence of vehicle shapes on system performance during engineering trade-offs, which are performed during conceptual design. A number of important aspects of the influence of vehicle behavior on the Pareto fronts are observed and discussed. There is a nearly complete convergence to narrow-wing solutions for the winged vehicle. Also, it is found that imposing pitch-stability for the winged vehicle at all angles of attack results in vehicle shapes which require upward control surface deflections during the majority of the entry.

Asymptotic behavior of curvature of surface elements in isotropic turbulence

NASA Technical Reports Server (NTRS)

Girimaji, S. S.

1991-01-01

The asymptotic behavior of the curvature of material elements in turbulence is investigated using Lagrangian velocity-gradient time series obtained from direct numerical simulations of isotropic turbulence. Several material-element ensembles of different initial curvatures and shapes are studied. It is found that, at long times, the (first five) moments of the logarithm of characteristic curvature and shape factor asymptote to values that are independent of the initial curvature or shape. This evidence strongly suggests that the asymptotic pdf's of the curvature and shape of material elements are stationary and independent of initial conditions. Irrespective of initial curvature or shape, the asymptotic shape of a material surface is cylindrical with a high probability.

Recoverable Wire-Shaped Supercapacitors with Ultrahigh Volumetric Energy Density for Multifunctional Portable and Wearable Electronics.

PubMed

Shi, Minjie; Yang, Cheng; Song, Xuefeng; Liu, Jing; Zhao, Liping; Zhang, Peng; Gao, Lian

2017-05-24

Wire-shaped supercapacitors (SCs) based on shape memory materials are of considerable interest for next-generation portable and wearable electronics. However, the bottleneck in this field is how to develop the devices with excellent electrochemical performance while well-maintaining recoverability and flexibility. Herein, a unique asymmetric electrode concept is put forward to fabricate smart wire-shaped SCs with ultrahigh energy density, which is realized by using porous carbon dodecahedra coated on NiTi alloy wire and flexible graphene fiber as yarn electrodes. Notably, the wire-shaped SCs not only exhibit high flexibility that can be readily woven into real clothing but also represent the available recoverable ability. When irreversible plastic deformations happen, the deformed shape of the devices can automatically resume the initial predesigned shape in a warm environment (about 35 °C). More importantly, the wire-shaped SCs act as efficient energy storage devices, which display high volumetric energy density (8.9 mWh/cm 3 ), volumetric power density (1080 mW/cm 3 ), strong durability in multiple mechanical states, and steady electrochemical behavior after repeated shape recovery processes. Considering their relative facile fabrication technology and excellent electrochemical performance, this asymmetric electrode strategy produced smart wire-shaped supercapacitors desirable for multifunctional portable and wearable electronics.

Grain size and shape evolution of experimentally deformed sediments: the role of slip rate

NASA Astrophysics Data System (ADS)

Balsamo, Fabrizio; Storti, Fabrizio; De Paola, Nicola

2016-04-01

Sediment deformation within fault zones occurs with a broad spectrum of mechanisms which, in turn, depend on intrinsic material properties (porosity, grain size and shape, etc.) and external factors (burial depth, fluid pressure, stress configuration, etc.). Fieldworks and laboratory measurements conducted in the last years in sediments faulted at shallow depth showed that cataclasis and grain size reduction can occur very close to the Earth surface (<1-2 km), and that fault displacement is one of the parameters controlling the amount of grain size, shape, and microtextural modifications in fault cores. In this contribution, we present a new set of microstructural observations combined with grain size and shape distribution data obtained from quart-feldspatic loose sediments (mean grain diameter 0.2 mm) experimentally deformed at different slip rates from subseismic (0.01 mm/s, 0.1 mm/s, 1 mm/s, 1 cm/s, and 10 cm/s) to coseismic slip rates (1 m/s). The experiments were originally performed at sigma n=14 MPa, with the same amount of slip (1.3 m), to constrain the frictional properties of such sediments at shallow confining pressures (<1 km). After the experiments, the granular materials deformed in the 0.1-1 mm-thick slip zones were prepared for both grain size distribution analyses and microstructural and textural analyses in thin sections. Grain size distribution analyses were obtained with a Malvern Mastersizer 3000 particle size laser-diffraction analyser, whereas grain shape data (angularity) were obtained by using image analysis technique on selected SEM-photomicrographs. Microstructural observations were performed at different scales with a standard optical microscope and with a SEM. Results indicate that mean grain diameter progressively decreases with increasing slip rates up to ~20-30 m, and that granulometric curves systematically modify as well, shifting toward finer grain sizes. Obtained fractal dimensions (D) indicate that D increases from ~2.3 up to >3 moving from subseismic to coseismic slip rates. Grain angularity also changes with increasing slip rates, being particles more smoothed and rounded in sediments deformed at coseismic slip rates. As a whole, our results indicate that both grain size and shape distributions of experimentally deformed sediments progressively changes from subseismic to coseismic slip rate, thus helping to understand the deformation mechanisms in natural fault zones and to predict frictional and permeability properties of faults affecting shallow sediments.

Impact of trailing edge shape on the wake and propulsive performance of pitching panels

NASA Astrophysics Data System (ADS)

Van Buren, T.; Floryan, D.; Brunner, D.; Senturk, U.; Smits, A. J.

2017-01-01

The effects of changing the trailing edge shape on the wake and propulsive performance of a pitching rigid panel are examined experimentally. The panel aspect ratio is AR=1 , and the trailing edges are symmetric chevron shapes with convex and concave orientations of varying degree. Concave trailing edges delay the natural vortex bending and compression of the wake, and the mean streamwise velocity field contains a single jet. Conversely, convex trailing edges promote wake compression and produce a quadfurcated wake with four jets. As the trailing edge shape changes from the most concave to the most convex, the thrust and efficiency increase significantly.

Laboratory performance of the shaped pupil coronagraphic architecture for the WFIRST/AFTA coronagraph

NASA Astrophysics Data System (ADS)

Cady, Eric; Mejia Prada, Camilo; An, Xin; Balasubramanian, Kunjithapatham; Diaz, Rosemary; Kasdin, N. Jeremy; Kern, Brian; Kuhnert, Andreas; Nemati, Bijan; Patterson, Keith; Poberezhskiy, Ilya; Riggs, A. J. Eldorado; Ryan, Daniel; Zhou, Hanying; Zimmer, Robert; Zimmerman, Neil T.

2015-09-01

One of the two primary architectures being tested for the WFIRST-AFTA coronagraph instrument is the shaped pupil coronagraph, which uses a binary aperture in a pupil plane to create localized regions of high contrast in a subsequent focal plane. The aperture shapes are determined by optimization, and can be designed to work in the presence of secondary obscurations and spiders - an important consideration for coronagraphy with WFIRST-AFTA. We present the current performance of the shaped pupil testbed, including the results of AFTA Milestone 2, in which ≍ 6 × 10-9 contrast was achieved in three independent runs starting from a neutral setting.

Laboratory Performance of the Shaped Pupil Coronagraphic Architecture for the WFIRST-AFTA Coronagraph

NASA Technical Reports Server (NTRS)

Cady, Eric; Mejia Prada, Camilo; An, Xin; Balasubramanian, Kunjithapatha; Diaz, Rosemary; Kasdin, N. Jeremy; Kern, Brian; Kuhnert, Andreas; Nemati, Bijan; Patterson, Keith;

A survey of pulse shape options for a revised plastic ablator ignition design

NASA Astrophysics Data System (ADS)

Clark, Daniel; Eder, David; Haan, Steven; Hinkel, Denise; Jones, Ogden; Marinak, Michael; Milovich, Jose; Peterson, Jayson; Robey, Harold; Salmonson, Jay; Smalyuk, Vladimir; Weber, Christopher

2014-10-01

Recent experimental results using the ``high foot'' pulse shape on the National Ignition Facility (NIF) have shown encouraging progress compared to earlier ``low foot'' experiments. These results strongly suggest that controlling ablation front instability growth can dramatically improve implosion performance, even in the presence of persistent, large, low-mode distortions. In parallel, Hydro. Growth Radiography experiments have so far validated the techniques used for modeling ablation front growth in NIF experiments. It is timely then to combine these two results and ask how current ignition pulse shapes could be modified so as to improve implosion performance, namely fuel compressibility, while maintaining the stability properties demonstrated with the high foot. This talk presents a survey of pulse shapes intermediate between the low and high foot extremes in search of a more optimal design. From the database of pulse shapes surveyed, a higher picket version of the original low foot pulse shape shows the most promise for improved compression without loss of stability. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Airframe Icing Research Gaps: NASA Perspective

NASA Technical Reports Server (NTRS)

Potapczuk, Mark

2009-01-01

qCurrent Airframe Icing Technology Gaps: Development of a full 3D ice accretion simulation model. Development of an improved simulation model for SLD conditions. CFD modeling of stall behavior for ice-contaminated wings/tails. Computational methods for simulation of stability and control parameters. Analysis of thermal ice protection system performance. Quantification of 3D ice shape geometric characteristics Development of accurate ground-based simulation of SLD conditions. Development of scaling methods for SLD conditions. Development of advanced diagnostic techniques for assessment of tunnel cloud conditions. Identification of critical ice shapes for aerodynamic performance degradation. Aerodynamic scaling issues associated with testing scale model ice shape geometries. Development of altitude scaling methods for thermal ice protections systems. Development of accurate parameter identification methods. Measurement of stability and control parameters for an ice-contaminated swept wing aircraft. Creation of control law modifications to prevent loss of control during icing encounters. 3D ice shape geometries. Collection efficiency data for ice shape geometries. SLD ice shape data, in-flight and ground-based, for simulation verification. Aerodynamic performance data for 3D geometries and various icing conditions. Stability and control parameter data for iced aircraft configurations. Thermal ice protection system data for simulation validation.

Augmented Endoscopic Images Overlaying Shape Changes in Bone Cutting Procedures.

PubMed

Nakao, Megumi; Endo, Shota; Nakao, Shinichi; Yoshida, Munehito; Matsuda, Tetsuya

2016-01-01

In microendoscopic discectomy for spinal disorders, bone cutting procedures are performed in tight spaces while observing a small portion of the target structures. Although optical tracking systems are able to measure the tip of the surgical tool during surgery, the poor shape information available during surgery makes accurate cutting difficult, even if preoperative computed tomography and magnetic resonance images are used for reference. Shape estimation and visualization of the target structures are essential for accurate cutting. However, time-varying shape changes during cutting procedures are still challenging issues for intraoperative navigation. This paper introduces a concept of endoscopic image augmentation that overlays shape changes to support bone cutting procedures. This framework handles the history of the location of the measured drill tip as a volume label and visualizes the remains to be cut overlaid on the endoscopic image in real time. A cutting experiment was performed with volunteers, and the feasibility of this concept was examined using a clinical navigation system. The efficacy of the cutting aid was evaluated with respect to the shape similarity, total moved distance of a cutting tool, and required cutting time. The results of the experiments showed that cutting performance was significantly improved by the proposed framework.

Parallel traveling-wave MRI: a feasibility study.

PubMed

Pang, Yong; Vigneron, Daniel B; Zhang, Xiaoliang

2012-04-01

Traveling-wave magnetic resonance imaging utilizes far fields of a single-piece patch antenna in the magnet bore to generate radio frequency fields for imaging large-size samples, such as the human body. In this work, the feasibility of applying the "traveling-wave" technique to parallel imaging is studied using microstrip patch antenna arrays with both the numerical analysis and experimental tests. A specific patch array model is built and each array element is a microstrip patch antenna. Bench tests show that decoupling between two adjacent elements is better than -26-dB while matching of each element reaches -36-dB, demonstrating excellent isolation performance and impedance match capability. The sensitivity patterns are simulated and g-factors are calculated for both unloaded and loaded cases. The results on B 1- sensitivity patterns and g-factors demonstrate the feasibility of the traveling-wave parallel imaging. Simulations also suggest that different array configuration such as patch shape, position and orientation leads to different sensitivity patterns and g-factor maps, which provides a way to manipulate B(1) fields and improve the parallel imaging performance. The proposed method is also validated by using 7T MR imaging experiments. Copyright © 2011 Wiley-Liss, Inc.

Improving the fiber coupling efficiency for DARWIN by loss-less shaping of the receive beams

NASA Astrophysics Data System (ADS)

Voland, Ch.; Weigel, Th.; Dreischer, Th.; Wallner, O.; Ergenzinger, K.; Ries, H.; Jetter, R.; Vosteen, A.

2017-11-01

For the DARWIN mission the extremely low planet signal levels require an optical instrument design with utmost efficiency to guarantee the required science performance. By shaping the transverse amplitude and phase distributions of the receive beams, the singlemode fibre coupling efficiency can be increased to almost 100%, thus allowing for a gain of more than 20% compared to conventional designs. We show that the use of "tailored freeform surfaces" for purpose of beam shaping dramatically reduces the coupling degradations, which otherwise result from mode mismatch between the Airy pattern of the image and the fibre mode, and therefore allows for achieving a performance close to the physical limitations. We present an application of tailored surfaces for building a beam shaping optics that shall enhance fibre coupling performance as core part of a space based interferometer in the future DARWIN mission and present performance predictions by wave-optical simulations. We assess the feasibility of manufacturing the corresponding tailored surfaces and describe the proof of concept demonstrator we use for experimental performance verification.

An evaluation of a silicone adhesive shaped heel dressing.

PubMed

Hampton, Sylvie

Tissue breakdown is complex and involves many factors. Pressure ulcer development in the heels is subject to extrinsic factors such as pressure, shear, friction and moisture. The heels are the most common sites for friction and shear damage, which can lead to blistering, skin erosion and tissue breakdown (Grey et al, 2006). To address the issues of wounds that are painful on dressing removal and friable skin, Smith & Nephew has introduced a soft silicone adhesive dressing to its Allevyn dressing range. Silicone does not adhere to wounded areas and can be removed gently without trauma to the periwound area. This paper discusses the findings of a 20-patient multi-site evaluation examining the performance and acceptability of Allevyn Gentle Border Heel dressing in the management of heel wounds.

Modeling and experiments of magneto-nanosensors for diagnostics of radiation exposure and cancer

PubMed Central

Kim, Dokyoon; Lee, Jung-Rok; Shen, Eric

2013-01-01

We present a resistive network model, protein assay data, and outlook of the giant magnetoresistive (GMR) spin-valve magneto-nanosensor platform ideal for multiplexed detection of protein biomarkers in solutions. The magneto-nanosensors are designed to have optimal performance considering several factors such as sensor dimension, shape anisotropy, and magnetic nanoparticle tags. The resistive network model indicates that thinner spin-valve sensors with narrower width lead to higher signals from magnetic nanoparticle tags. Standard curves and real-time measurements showed a sensitivity of ~10 pM for phosphorylated-structural maintenance of chromosome 1 (phosphor-SMC1), ~53 fM for granulocyte colony stimulation factor (GCSF), and ~460 fM for interleukin-6 (IL6), which are among the representative biomarkers for radiation exposure and cancer. PMID:22763391

The effect of ice crystal shape on aircraft contrails

NASA Astrophysics Data System (ADS)

Meza Castillo, Omar E.

Aircraft contrails are a common phenomenon observed in the sky. They are formed mainly of water, from the ambient atmosphere and as a by-product of the combustion process, in the form of ice crystals. They have been identified as a potential contributor to global warming. Some contrails can be long-lived and create man-made cloud cover, thus possibly altering the radiative balance of the earth. There has been a great deal of research on various aspects of contrail development, but to date, little has been done on the influence of ice crystal shapes on the contrail evolution. In-situ studies have reported that young contrails are mainly quasi-spherical crystals while older contrails can have a much more diverse spectrum of possible shapes. The most common shapes found in contrails are quasi-spherical, hexagonal columns, hexagonal plates, and bullet rosettes. Numerical simulations of contrails to date typically have assumed "spherical" as the default ice shape. This work simulated contrail development with a large eddy simulation (LES) model that implemented both spherical and non-spherical shapes to examine the effects. The included shape effect parameters, such as capacitance coefficient, ventilation factor, Kelvin effect, fall velocity and ice crystal surface area, help to establish the shape difference in the results. This study also investigated initial sensitivities to an additional ice parameter, the ice deposition coefficient. The literature shows conflicting values for this coefficient over a wide range. In the course of this investigation a comparison of various ice metrics was made for simulations with different assumed crystal shapes (spheres, hexagonal columns, hexagonal plates, bullet rosettes and combination of shapes). The simulations were performed at early and late contrail time, with a range of ice crystal sizes, and with/without coupled radiation. In young and older contrails and without coupled radiation, the difference from the shape effect in ice crystal number, N(t), is not significant compared with the level of uncertainty. In young contrails, the difference between spherical and non-spherical shapes in N(t) is less than 7% for relatively large ice particles and 23% for relatively small ice particles. The ice mass, M(t), is not significantly affected by the crystal shapes, with less than 8% difference. However, the ice surface area, S(t), is the ice metric more sensitive to crystal shape, with a maximum difference of 68%. It increases at late time, though it is mainly governed by geometrical rather than dynamical effects. The small sensitivity to shape effects in the ice contrail metrics when radiation is not included suggests that the spherical shape will provide a reasonable representation for all shapes found in the in-situ studies. The radiation is included at late time, when the lasting effects of contrails are more critical. The inclusion of coupled radiation increases the level of dispersion in the results and hence increases slightly the differences due to shape effects. The small difference is also observed in the infrared heating rates of contrails.

Characterization of equipment for shaping and imaging hadron minibeams

NASA Astrophysics Data System (ADS)

Pugatch, V.; Brons, S.; Campbell, M.; Kovalchuk, O.; Llopart, X.; Martínez-Rovira, I.; Momot, Ie.; Okhrimenko, O.; Prezado, Y.; Sorokin, Yu.

2017-11-01

For the feasibility studies of spatially fractionated hadron therapy prototypes of the equipment for hadron minibeams shaping and monitoring have been designed, built and tested. The collimators design was based on Monte Carlo simulations (Gate v.6.2). Slit and matrix collimators were used for minibeams shaping. Gafchromic films, micropixel detectors Timepix in a hybrid as well as metal mode were tested for measuring hadrons intensity distribution in minibeams. An overall beam profile was measured by the metal microstrip detector. The performance of a mini-beams shaping and monitoring equipment was characterized exploring low energy protons at the KINR Tandem generator as well as high energy carbon and oxygen ion beams at HIT (Heidelberg). The results demonstrate reliable performance of the tested equipment for shaping and imaging hadron mini-beam structures.

Optimal Embedding for Shape Indexing in Medical Image Databases

PubMed Central

Qian, Xiaoning; Tagare, Hemant D.; Fulbright, Robert K.; Long, Rodney; Antani, Sameer

2010-01-01

This paper addresses the problem of indexing shapes in medical image databases. Shapes of organs are often indicative of disease, making shape similarity queries important in medical image databases. Mathematically, shapes with landmarks belong to shape spaces which are curved manifolds with a well defined metric. The challenge in shape indexing is to index data in such curved spaces. One natural indexing scheme is to use metric trees, but metric trees are prone to inefficiency. This paper proposes a more efficient alternative. We show that it is possible to optimally embed finite sets of shapes in shape space into a Euclidean space. After embedding, classical coordinate-based trees can be used for efficient shape retrieval. The embedding proposed in the paper is optimal in the sense that it least distorts the partial Procrustes shape distance. The proposed indexing technique is used to retrieve images by vertebral shape from the NHANES II database of cervical and lumbar spine x-ray images maintained at the National Library of Medicine. Vertebral shape strongly correlates with the presence of osteophytes, and shape similarity retrieval is proposed as a tool for retrieval by osteophyte presence and severity. Experimental results included in the paper evaluate (1) the usefulness of shape-similarity as a proxy for osteophytes, (2) the computational and disk access efficiency of the new indexing scheme, (3) the relative performance of indexing with embedding to the performance of indexing without embedding, and (4) the computational cost of indexing using the proposed embedding versus the cost of an alternate embedding. The experimental results clearly show the relevance of shape indexing and the advantage of using the proposed embedding. PMID:20163981

Optimal embedding for shape indexing in medical image databases.

PubMed

Qian, Xiaoning; Tagare, Hemant D; Fulbright, Robert K; Long, Rodney; Antani, Sameer

2010-06-01

This paper addresses the problem of indexing shapes in medical image databases. Shapes of organs are often indicative of disease, making shape similarity queries important in medical image databases. Mathematically, shapes with landmarks belong to shape spaces which are curved manifolds with a well defined metric. The challenge in shape indexing is to index data in such curved spaces. One natural indexing scheme is to use metric trees, but metric trees are prone to inefficiency. This paper proposes a more efficient alternative. We show that it is possible to optimally embed finite sets of shapes in shape space into a Euclidean space. After embedding, classical coordinate-based trees can be used for efficient shape retrieval. The embedding proposed in the paper is optimal in the sense that it least distorts the partial Procrustes shape distance. The proposed indexing technique is used to retrieve images by vertebral shape from the NHANES II database of cervical and lumbar spine X-ray images maintained at the National Library of Medicine. Vertebral shape strongly correlates with the presence of osteophytes, and shape similarity retrieval is proposed as a tool for retrieval by osteophyte presence and severity. Experimental results included in the paper evaluate (1) the usefulness of shape similarity as a proxy for osteophytes, (2) the computational and disk access efficiency of the new indexing scheme, (3) the relative performance of indexing with embedding to the performance of indexing without embedding, and (4) the computational cost of indexing using the proposed embedding versus the cost of an alternate embedding. The experimental results clearly show the relevance of shape indexing and the advantage of using the proposed embedding. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Performance drifts in two-finger cyclical force production tasks performed by one and two actors.

PubMed

Hasanbarani, Fariba; Reschechtko, Sasha; Latash, Mark L

2018-03-01

We explored changes in the cyclical two-finger force performance task caused by turning visual feedback off performed either by the index and middle fingers of the dominant hand or by two index fingers of two persons. Based on an earlier study, we expected drifts in finger force amplitude and midpoint without a drift in relative phase. The subjects performed two rhythmical tasks at 1 Hz while paced by an auditory metronome. One of the tasks required cyclical changes in total force magnitude without changes in the sharing of the force between the two fingers. The other task required cyclical changes in the force sharing without changing total force magnitude. Subjects were provided with visual feedback, which showed total force magnitude and force sharing via cursor motion along the vertical and horizontal axes, respectively. Further, visual feedback was turned off, first on the variable that was not required to change and then on both variables. Turning visual feedback off led to a mean force drift toward lower magnitudes while force amplitude increased. There was a consistent drift in the relative phase in the one-hand task with the index finger leading the middle finger. No consistent relative phase drift was seen in the two-person tasks. The shape of the force cycle changed without visual feedback reflected in the lower similarity to a perfect cosine shape and in the higher time spent at lower force magnitudes. The data confirm findings of earlier studies regarding force amplitude and midpoint changes, but falsify predictions of an earlier proposed model with respect to the relative phase changes. We discuss factors that could contribute to the observed relative phase drift in the one-hand tasks including the leader-follower pattern generalized for two-effector tasks performed by one person.

The performance improvement of automatic classification among obstructive lung diseases on the basis of the features of shape analysis, in addition to texture analysis at HRCT

NASA Astrophysics Data System (ADS)

Lee, Youngjoo; Kim, Namkug; Seo, Joon Beom; Lee, JuneGoo; Kang, Suk Ho

2007-03-01

In this paper, we proposed novel shape features to improve classification performance of differentiating obstructive lung diseases, based on HRCT (High Resolution Computerized Tomography) images. The images were selected from HRCT images, obtained from 82 subjects. For each image, two experienced radiologists selected rectangular ROIs with various sizes (16x16, 32x32, and 64x64 pixels), representing each disease or normal lung parenchyma. Besides thirteen textural features, we employed additional seven shape features; cluster shape features, and Top-hat transform features. To evaluate the contribution of shape features for differentiation of obstructive lung diseases, several experiments were conducted with two different types of classifiers and various ROI sizes. For automated classification, the Bayesian classifier and support vector machine (SVM) were implemented. To assess the performance and cross-validation of the system, 5-folding method was used. In comparison to employing only textural features, adding shape features yields significant enhancement of overall sensitivity(5.9, 5.4, 4.4% in the Bayesian and 9.0, 7.3, 5.3% in the SVM), in the order of ROI size 16x16, 32x32, 64x64 pixels, respectively (t-test, p<0.01). Moreover, this enhancement was largely due to the improvement on class-specific sensitivity of mild centrilobular emphysema and bronchiolitis obliterans which are most hard to differentiate for radiologists. According to these experimental results, adding shape features to conventional texture features is much useful to improve classification performance of obstructive lung diseases in both Bayesian and SVM classifiers.

Prechamber Compression-Ignition Engine Performance

NASA Technical Reports Server (NTRS)

Moore, Charles S; Collins, John H , Jr

1938-01-01

Single-cylinder compression-ignition engine tests were made to investigate the performance characteristics of prechamber type of cylinder head. Certain fundamental variables influencing engine performance -- clearance distribution, size, shape, and direction of the passage connecting the cylinder and prechamber, shape of prechamber, cylinder clearance, compression ratio, and boosting -- were independently tested. Results of motoring and of power tests, including several typical indicator cards, are presented.

The association between a body shape index and cardiovascular risk in overweight and obese children and adolescents.

PubMed

Mameli, Chiara; Krakauer, Nir Y; Krakauer, Jesse C; Bosetti, Alessandra; Ferrari, Chiara Matilde; Moiana, Norma; Schneider, Laura; Borsani, Barbara; Genoni, Teresa; Zuccotti, Gianvincenzo

2018-01-01

A Body Shape Index (ABSI) and normalized hip circumference (Hip Index, HI) have been recently shown to be strong risk factors for mortality and for cardiovascular disease in adults. We conducted an observational cross-sectional study to evaluate the relationship between ABSI, HI and cardiometabolic risk factors and obesity-related comorbidities in overweight and obese children and adolescents aged 2-18 years. We performed multivariate linear and logistic regression analyses with BMI, ABSI, and HI age and sex normalized z scores as predictors to examine the association with cardiometabolic risk markers (systolic and diastolic blood pressure, fasting glucose and insulin, total cholesterol and its components, transaminases, fat mass % detected by bioelectrical impedance analysis) and obesity-related conditions (including hepatic steatosis and metabolic syndrome). We recruited 217 patients (114 males), mean age 11.3 years. Multivariate linear regression showed a significant association of ABSI z score with 10 out of 15 risk markers expressed as continuous variables, while BMI z score showed a significant correlation with 9 and HI only with 1. In multivariate logistic regression to predict occurrence of obesity-related conditions and above-threshold values of risk factors, BMI z score was significantly correlated to 7 out of 12, ABSI to 5, and HI to 1. Overall, ABSI is an independent anthropometric index that was significantly associated with cardiometabolic risk markers in a pediatric population affected by overweight and obesity.

Mutations in cell elongation genes mreB, mrdA and mrdB suppress the shape defect of RodZ-deficient cells.

PubMed

Shiomi, Daisuke; Toyoda, Atsushi; Aizu, Tomoyuki; Ejima, Fumio; Fujiyama, Asao; Shini, Tadasu; Kohara, Yuji; Niki, Hironori

2013-03-01

RodZ interacts with MreB and both factors are required to maintain the rod shape of Escherichia coli. The assembly of MreB into filaments regulates the subcellular arrangement of a group of enzymes that synthesizes the peptidoglycan (PG) layer. However, it is still unknown how polymerization of MreB determines the rod shape of bacterial cells. Regulatory factor(s) are likely to be involved in controlling the function and dynamics of MreB. We isolated suppressor mutations to partially recover the rod shape in rodZ deletion mutants and found that some of the suppressor mutations occurred in mreB. All of the mreB mutations were in or in the vicinity of domain IA of MreB. Those mreB mutations changed the property of MreB filaments in vivo. In addition, suppressor mutations were found in the periplasmic regions in PBP2 and RodA, encoded by mrdA and mrdB genes. Similar to MreB and RodZ, PBP2 and RodA are pivotal to the cell wall elongation process. Thus, we found that mutations in domain IA of MreB and in the periplasmic domain of PBP2 and RodA can restore growth and rod shape to ΔrodZ cells, possibly by changing the requirements of MreB in the process. © 2013 Blackwell Publishing Ltd.

Mutations in cell elongation genes mreB, mrdA and mrdB suppress the shape defect of RodZ-deficient cells

PubMed Central

Shiomi, Daisuke; Toyoda, Atsushi; Aizu, Tomoyuki; Ejima, Fumio; Fujiyama, Asao; Shini, Tadasu; Kohara, Yuji; Niki, Hironori

2013-01-01

RodZ interacts with MreB and both factors are required to maintain the rod shape of Escherichia coli. The assembly of MreB into filaments regulates the subcellular arrangement of a group of enzymes that synthesizes the peptidoglycan (PG) layer. However, it is still unknown how polymerization of MreB determines the rod shape of bacterial cells. Regulatory factor(s) are likely to be involved in controlling the function and dynamics of MreB. We isolated suppressor mutations to partially recover the rod shape in rodZ deletion mutants and found that some of the suppressor mutations occurred in mreB. All of the mreB mutations were in or in the vicinity of domain IA of MreB. Those mreB mutations changed the property of MreB filaments in vivo. In addition, suppressor mutations were found in the periplasmic regions in PBP2 and RodA, encoded by mrdA and mrdB genes. Similar to MreB and RodZ, PBP2 and RodA are pivotal to the cell wall elongation process. Thus, we found that mutations in domain IA of MreB and in the periplasmic domain of PBP2 and RodA can restore growth and rod shape to ΔrodZ cells, possibly by changing the requirements of MreB in the process. PMID:23301723

Upscaling gas permeability in tight-gas sandstones

NASA Astrophysics Data System (ADS)

Ghanbarian, B.; Torres-Verdin, C.; Lake, L. W.; Marder, M. P.

2017-12-01

Klinkenberg-corrected gas permeability (k) estimation in tight-gas sandstones is essential for gas exploration and production in low-permeability porous rocks. Most models for estimating k are a function of porosity (ϕ), tortuosity (τ), pore shape factor (s) and a characteristic length scale (lc). Estimation of the latter, however, has been the subject of debate in the literature. Here we invoke two different upscaling approaches from statistical physics: (1) the EMA and (2) critical path analysis (CPA) to estimate lc from pore throat-size distribution derived from mercury intrusion capillary pressure (MICP) curve. τ is approximated from: (1) concepts of percolation theory and (2) formation resistivity factor measurements (F = τ/ϕ). We then estimate k of eighteen tight-gas sandstones from lc, τ, and ϕ by assuming two different pore shapes: cylindrical and slit-shaped. Comparison with Klinkenberg-corrected k measurements showed that τ was estimated more accurately from F measurements than from percolation theory. Generally speaking, our results implied that the EMA estimated k within a factor of two of the measurements and more precisely than CPA. We further found that the assumption of cylindrical pores yielded more accurate k estimates when τ was estimated from concepts of percolation theory than the assumption of slit-shaped pores. However, the EMA with slit-shaped pores estimated k more precisely than that with cylindrical pores when τ was estimated from F measurements.

A repeatable geometric morphometric approach to the analysis of hand entheseal three-dimensional form.

PubMed

Karakostis, Fotios Alexandros; Hotz, Gerhard; Scherf, Heike; Wahl, Joachim; Harvati, Katerina

2018-05-01

The purpose of this study was to put forth a precise landmark-based technique for reconstructing the three-dimensional shape of human entheseal surfaces, to investigate whether the shape of human entheses is related to their size. The effects of age-at-death and bone length on entheseal shapes were also assessed. The sample comprised high-definition three-dimensional models of three right hand entheseal surfaces, which correspond to 45 male adult individuals of known age. For each enthesis, a particular landmark configuration was introduced, whose precision was tested both within and between observers. The effect of three-dimensional size, age-at-death, and bone length on shape was investigated through shape regression. The method presented high intra-observer and inter-observer repeatability. All entheses showed significant allometry, with the area of opponens pollicis demonstrating the most substantial relationship. This was particularly due to variation related to its proximal elongated ridge. The effect of age-at-death and bone length on entheses was limited. The introduced methodology can set a reliable basis for further research on the factors affecting entheseal shape. Using both size and shape, variables can provide further information on entheseal variation and its biomechanical implications. The low entheseal variation by age verifies that specimens under 50 years of age are not substantially affected by age-related changes. The lack of correlation between entheseal shape and bone length or age implies that other factors may regulate entheseal surfaces. Future research should focus on multivariate shape patterns among entheses and their association with occupation. © 2018 Wiley Periodicals, Inc.

Aging in the Male Face: Intrinsic and Extrinsic Factors.

PubMed

Keaney, Terrence C

2016-07-01

Gender is one of the most significant factors that influence facial anatomy and behavior, both key factors in the aging process. To review male facial anatomy, physiology, and behavior and how it contributes to sexual dimorphism in facial aging. A MEDLINE search was performed for publications on gender differences in facial anatomy, aging, cutaneous physiology, and behavior. There are differences in both intrinsic and extrinsic aging factors in men. Men have a thicker epidermis and dermis with more active cutaneous appendages including hair growth. Male skin has a reduced antioxidant capacity and increased ultraviolet-induced immunosuppression. The male face is larger and has a unique square shape with less subcutaneous soft tissue, especially at the medial cheek. Men are also more prone to smoking and exhibiting poor sun-protective behavior. The differences in intrinsic and extrinsic aging factors contribute to poor facial aging in men. Men develop more severe rhytides in a unique pattern, show increased periocular aging changes, and are more prone to hair loss. This review provides insight into the factors contributing to accelerated male facial aging. Understanding gender differences in aging will help physicians tailor cosmetic treatments for men and minimize extrinsic aging factors.

Improved sensitivity by post-column chemical environment modification of CE-ESI-MS using a flow-through microvial interface.

PubMed

Risley, Jessica May; Chen, David Da Yong

2017-06-01

Post-column chemical environment modification can affect detection sensitivity and signal appearance when capillary electrophoresis is coupled through electrospray ionization to mass spectrometry (CE-ESI-MS). In this study, changes in the signal intensity and peak shape of N-Acetylneuraminic acid (Neu5Ac) were examined when the modifier solution used in a flow-through microvial interface for CE-ESI-MS was prepared using an acidic or basic background electrolyte (BGE) composition. The use of a basic modifier resulted in improved detection compared to the results obtained when an acidic modifier was used in negative ion mode. Increased sensitivity and more symmetrical peak shape were obtained. Using an acidic modifier, the LOD of Neu5Ac was 47.7 nM, whereas for a basic modifier, the LOD of Neu5Ac was 5.20 nM. The calculated asymmetry factor at 100 nM of Neu5Ac ranged from 0.71 to 1.5 when an acidic modifier was used, while the factor ranged from 1.0 to 1.1 when a basic modifier was used. Properly chosen post-column chemical modification can have a significant effect on the performance of the CE-MS system. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Understanding the Delamination Risk of a Trilayer Tablet Using Minipiloting Tools.

PubMed

Tao, Jing; Robertson-Lavalle, Sophia; Pandey, Preetanshu; Badawy, Sherif

2017-11-01

A multilayer tablet is one of the formulation options used to mitigate chemical and physical incompatibility between different drug substances. Feasibility studies of multilayer tablets are often conducted using round flat-faced punch tooling. However, the link between different tooling designs and multilayer tablet performance is not well established. This study uses a prototype trilayer tablet and examines tooling design considerations when conducting small-scale studies to gauge the risk of interfacial defects. The impact of tablet weight and dimensions was evaluated to gain understanding of the effect of scale-up/down of tablet size. The factors in tooling selection, including tablet shape, cup depth, and size of embossing were evaluated to gain insight on the impact of tooling design on the interfacial strength of the trilayer tablet. It was found that tablet weight and dimensions can significantly affect the interfacial strength due to their impact on force transmission during compression and the retardation force from the die wall during ejection. Round flat-faced tooling generated trilayer tablets of the strongest interfacial strength compared to typical commercial tablets-oval shaped with concave surfaces. These factors should be accounted for when using round flat compacts to assess the interface risks of a multilayer tablet. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Ecological explanations to island gigantism: dietary niche divergence, predation, and size in an endemic lizard.

PubMed

Runemark, Anna; Sagonas, Kostas; Svensson, Erik I

2015-08-01

Although rapid evolution of body size on islands has long been known, the ecological mechanisms behind this island phenomenon remain poorly understood. Diet is an important selective pressure for morphological divergence. Here we investigate if selection for novel diets has contributed to the multiple independent cases of island gigantism in the Skyros wall lizard (Podarcis gaigeae) and if diet, predation, or both factors best explain island gigantism. We combined data on body size, shape, bite force, and realized and available diets to address this. Several lines of evidence suggest that diet has contributed to the island gigantism. The larger islet lizards have relatively wider heads and higher bite performance in relation to mainland lizards than would be expected from size differences alone. The proportions of consumed and available hard prey are higher on islets than mainland localities, and lizard body size is significantly correlated with the proportion of hard prey. Furthermore, the main axis of divergence in head shape is significantly correlated with dietary divergence. Finally, a model with only diet and one including diet and predation regime explain body size divergence equally well. Our results suggest that diet is an important ecological factor behind insular body size divergence, but could be consistent with an additional role for predation.

Development of a new connection for precast concrete walls subjected to cyclic loading

NASA Astrophysics Data System (ADS)

Vaghei, Ramin; Hejazi, Farzad; Taheri, Hafez; Jaafar, Mohd Saleh; Aziz, Farah Nora Aznieta Abdul

2017-01-01

The Industrialized Building System (IBS) was recently introduced to minimize the time and cost of project construction. Accordingly, ensuring the integration of the connection of precast components in IBS structures is an important factor that ensures stability of buildings subjected to dynamic loads from earthquakes, vehicles, and machineries. However, structural engineers still lack knowledge on the proper connection and detailed joints of IBS structure construction. Therefore, this study proposes a special precast concrete wall-to-wall connection system for dynamic loads that resists multidirectional imposed loads and reduces vibration effects (PI2014701723). This system is designed to connect two adjacent precast wall panels by using two steel U-shaped channels (i.e., male and female joints). During casting, each joint is adapted for incorporation into a respective wall panel after considering the following conditions: one side of the steel channel opens into the thickness face of the panel; a U-shaped rubber is implemented between the two channels to dissipate the vibration effect; and bolts and nuts are used to create an extension between the two U-shaped male and female steel channels. The developed finite element model of the precast wall is subjected to cyclic loads to evaluate the performance of the proposed connection during an imposed dynamic load. Connection performance is then compared with conventional connections based on the energy dissipation, stress, deformation, and concrete damage in the plastic range. The proposed precast connection is capable of exceeding the energy absorption of precast walls subjected to dynamic load, thereby improving its resistance behavior in all principal directions.

Beam shaping to improve the free-electron laser performance at the Linac Coherent Light Source

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

Ding, Y.; Bane, K. L. F.; Colocho, W.

2016-10-27

A new operating mode has been developed for the Linac Coherent Light Source (LCLS) in which we shape the longitudinal phase space of the electron beam. This mode of operation is realized using a horizontal collimator located in the middle of the first bunch compressor to truncate the head and tail of the beam. With this method, the electron beam longitudinal phase space and current profile are reshaped, and improvement in lasing performance can be realized. As a result, we present experimental studies at the LCLS of the beam shaping effects on the free-electron laser performance.

The effects of overall robot shape on the emotions invoked in users and the perceived personalities of robot.

PubMed

Hwang, Jihong; Park, Taezoon; Hwang, Wonil

2013-05-01

The affective interaction between human and robots could be influenced by various aspects of robots, which are appearance, countenance, gesture, voice, etc. Among these, the overall shape of robot could play a key role in invoking desired emotions to the users and bestowing preferred personalities to robots. In this regard, the present study experimentally investigates the effects of overall robot shape on the emotions invoked in users and the perceived personalities of robot with an objective of deriving guidelines for the affective design of service robots. In so doing, 27 different shapes of robot were selected, modeled and fabricated, which were combinations of three different shapes of head, trunk and limb (legs and arms) - rectangular-parallelepiped, cylindrical and human-like shapes. For the experiment, visual images and real prototypes of these robot shapes were presented to participants, and emotions invoked and personalities perceived from the presented robots were measured. The results showed that the overall shape of robot arouses any of three emotions named 'concerned', 'enjoyable' and 'favorable', among which 'concerned' emotion is negatively correlated with the 'big five personality factors' while 'enjoyable' and 'favorable' emotions are positively correlated. It was found that the 'big five personality factors', and 'enjoyable' and 'favorable' emotions are more strongly perceived through the real prototypes than through the visual images. It was also found that the robot shape consisting of cylindrical head, human-like trunk and cylindrical head is the best for 'conscientious' personality and 'favorable' emotion, the robot shape consisting of cylindrical head, human-like trunk and human-like limb for 'extroverted' personality, the robot shape consisting of cylindrical head, cylindrical trunk and cylindrical limb for 'anti-neurotic' personality, and the robot shape consisting of rectangular-parallelepiped head, human-like trunk and human-like limb for 'enjoyable' emotion. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Membrane re-modelling by BAR domain superfamily proteins via molecular and non-molecular factors.

PubMed

Nishimura, Tamako; Morone, Nobuhiro; Suetsugu, Shiro

2018-04-17

Lipid membranes are structural components of cell surfaces and intracellular organelles. Alterations in lipid membrane shape are accompanied by numerous cellular functions, including endocytosis, intracellular transport, and cell migration. Proteins containing Bin-Amphiphysin-Rvs (BAR) domains (BAR proteins) are unique, because their structures correspond to the membrane curvature, that is, the shape of the lipid membrane. BAR proteins present at high concentration determine the shape of the membrane, because BAR domain oligomers function as scaffolds that mould the membrane. BAR proteins co-operate with various molecular and non-molecular factors. The molecular factors include cytoskeletal proteins such as the regulators of actin filaments and the membrane scission protein dynamin. Lipid composition, including saturated or unsaturated fatty acid tails of phospholipids, also affects the ability of BAR proteins to mould the membrane. Non-molecular factors include the external physical forces applied to the membrane, such as tension and friction. In this mini-review, we will discuss how the BAR proteins orchestrate membrane dynamics together with various molecular and non-molecular factors. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

A Method for Producing a Shaped Contour Radiation Pattern Using a Single Shaped Reflector and a Single Feed

NASA Technical Reports Server (NTRS)

Cherrette, A. R.; Lee, S. W.; Acosta, R. J.

1988-01-01

Eliminating the corporate feed network in shaped contour beam antennas will reduce the expense, weight, and RF loss of the antenna system. One way of producing a shaped contour beam without using a feed network is to use a single shaped reflector with a single feed element. For a prescribed contour beam and feed, an optimization method for designing the reflector shape is given. As a design example, a shaped reflector is designed to produce a continental U.S. coverage (CONUS) beam. The RF performance of the shaped reflector is then verified by physical optics.

The genetics of shovel shape in maxillary central incisors in man.

PubMed

Blanco, R; Chakraborty, R

1976-03-01

From dental casts of 94 parent-offspring and 127 full-sib pairs, sampled from two Chilean populations, shovelling indices are computed to measure the degree of shovelling of maxillary central incisors quantitatively. Genetic correlations are computed to determine the role of genetic factors in explaining the variation in this trait. Assuming only hereditary factors to be responsible for the transmission of shovel shape, 68% of total variability is ascribed to the additive effect of genes.

Higher-order vibrational mode frequency tuning utilizing fishbone-shaped microelectromechanical systems resonator

NASA Astrophysics Data System (ADS)

Suzuki, Naoya; Tanigawa, Hiroshi; Suzuki, Kenichiro

2013-04-01

Resonators based on microelectromechanical systems (MEMS) have received considerable attention for their applications for wireless equipment. The requirements for this application include small size, high frequency, wide bandwidth and high portability. However, few MEMS resonators with wide-frequency tuning have been reported. A fishbone-shaped resonator has a resonant frequency with a maximum response that can be changed according to the location and number of several exciting electrodes. Therefore, it can be expected to provide wide-frequency tuning. The resonator has three types of electrostatic forces that can be generated to deform a main beam. We evaluate the vibrational modes caused by each exciting electrodes by comparing simulated results with measured ones. We then successfully demonstrate the frequency tuning of the first to fifth resonant modes by using the algorithm we propose here. The resulting frequency tuning covers 178 to 1746 kHz. In addition, we investigate the suppression of the anchor loss to enhance the Q-factor. An experiment shows that tapered-shaped anchors provide a higher Q-factor than rectangular-shaped anchors. The Q-factor of the resonators supported by suspension beams is also discussed. Because the suspension beams cause complicated vibrational modes for higher frequencies, the enhancement of the Q-factor for high vibrational modes cannot be obtained here. At present, the tapered-anchor resonators are thought to be most suitable for frequency tuning applications.

Ventral and Dorsal Visual Stream Contributions to the Perception of Object Shape and Object Location

PubMed Central

Zachariou, Valentinos; Klatzky, Roberta; Behrmann, Marlene

2017-01-01

Growing evidence suggests that the functional specialization of the two cortical visual pathways may not be as distinct as originally proposed. Here, we explore possible contributions of the dorsal “where/how” visual stream to shape perception and, conversely, contributions of the ventral “what” visual stream to location perception in human adults. Participants performed a shape detection task and a location detection task while undergoing fMRI. For shape detection, comparable BOLD activation in the ventral and dorsal visual streams was observed, and the magnitude of this activation was correlated with behavioral performance. For location detection, cortical activation was significantly stronger in the dorsal than ventral visual pathway and did not correlate with the behavioral outcome. This asymmetry in cortical profile across tasks is particularly noteworthy given that the visual input was identical and that the tasks were matched for difficulty in performance. We confirmed the asymmetry in a subsequent psychophysical experiment in which participants detected changes in either object location or shape, while ignoring the other, task-irrelevant dimension. Detection of a location change was slowed by an irrelevant shape change matched for difficulty, but the reverse did not hold. We conclude that both ventral and dorsal visual streams contribute to shape perception, but that location processing appears to be essentially a function of the dorsal visual pathway. PMID:24001005

Understanding the Photovoltaic Performance of Perovskite-Spirobifluorene Solar Cells.

PubMed

Song, Zhen; Liu, Jiang; Wang, Gang; Zuo, Wentao; Liao, Cheng; Mei, Jun

2017-11-03

Lead halide perovskite solar cells with remarkable power conversion efficiency have attracted much attention in recent years. However, there still exist many problems with their use that are not completely understood, and further studies are needed. Herein, the hole-transport layer dependence of the photovoltaic performance of perovskite solar cells is investigated in detail. It is found that devices freshly prepared using pristine 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) and Li-doped spiro-OMeTAD as hole-transport layers exhibit S-shaped current density-voltage curves with poor fill factors. The devices show progressively improved fill factors and efficiencies upon exposure to air, which is attributed to air-induced conductivity improvement in the spiro-OMeTAD layer. After introducing a cobalt salt dopant (FK209) into the spiro-OMeTAD layer, the corresponding devices show remarkable performance without the need of air exposure. These results confirm that the dopant not only increases the conductivity of spiro-OMeTAD layer, but also tunes the surface potential, which helps to improve charge transport and reduce the recombination loss. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cruising the rain forest floor: butterfly wing shape evolution and gliding in ground effect.

PubMed

Cespedes, Ann; Penz, Carla M; DeVries, Philip J

2015-05-01

Flight is a key innovation in the evolutionary success of insects and essential to dispersal, territoriality, courtship and oviposition. Wing shape influences flight performance and selection likely acts to maximize performance for conducting essential behaviours that in turn results in the evolution of wing shape. As wing shape also contributes to fitness, optimal shapes for particular flight behaviours can be assessed with aerodynamic predictions and placed in an ecomorphological context. Butterflies in the tribe Haeterini (Nymphalidae) are conspicuous members of understorey faunas in lowland Neotropical forests. Field observations indicate that the five genera in this clade differ in flight height and behaviour: four use gliding flight at the forest floor level, and one utilizes flapping flight above the forest floor. Nonetheless, the association of ground level gliding flight behaviour and wing shape has never been investigated in this or any other butterfly group. We used landmark-based geometric morphometrics to test whether wing shapes in Haeterini and their close relatives reflected observed flight behaviours. Four genera of Haeterini and some distantly related Satyrinae showed significant correspondence between wing shape and theoretical expectations in performance trade-offs that we attribute to selection for gliding in ground effect. Forewing shape differed between sexes for all taxa, and male wing shapes were aerodynamically more efficient for gliding flight than corresponding females. This suggests selection acts differentially on male and female wing shapes, reinforcing the idea that sex-specific flight behaviours contribute to the evolution of sexual dimorphism. Our study indicates that wing shapes in Haeterini butterflies evolved in response to habitat-specific flight behaviours, namely gliding in ground effect along the forest floor, resulting in ecomorphological partitions of taxa in morphospace. The convergent flight behaviour and wing morphology between tribes of Satyrinae suggest that the flight environment may offset phylogenetic constraints. Overall, this study provides a basis for exploring similar patterns of wing shape evolution in other taxa that glide in ground effect. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

Waveform synthesizer

DOEpatents

Franks, L.A.; Nelson, M.A.

1979-12-07

The invention is a method by which an optical pulse of an arbitrary but defined shape may be transformed into a virtual multitude of optical or electrical output pulse shapes. Since the method is not limited to any particular input pulse shape, the output pulse shapes that can be generated thereby are virtually unlimited. Moreover, output pulse widths as narrow as about 0.1 nsec can be readily obtained since optical pulses of less than a few picoseconds are available for use as driving pulses. The range of output pulse widths obtainable is very large, the limiting factors being the driving source energy and the particular shape of the desired output pulse.

Phenotypic variation in dorsal fin morphology of coastal bottlenose dolphins (Tursiops truncatus) off Mexico

PubMed Central

Rocha-Olivares, Axayácatl; Morteo, Rodrigo; Weller, David W.

2017-01-01

Geographic variation in external morphology is thought to reflect an interplay between genotype and the environment. Morphological variation has been well-described for a number of cetacean species, including the bottlenose dolphin (Tursiops truncatus). In this study we analyzed dorsal fin morphometric variation in coastal bottlenose dolphins to search for geographic patterns at different spatial scales. A total of 533 dorsal fin images from 19 available photo-identification catalogs across the three Mexican oceanic regions (Pacific Ocean n = 6, Gulf of California n = 6 and, Gulf of Mexico n = 7) were used in the analysis. Eleven fin shape measurements were analyzed to evaluate fin polymorphism through multivariate tests. Principal Component Analysis on log-transformed standardized ratios explained 94% of the variance. Canonical Discriminant Function Analysis on factor scores showed separation among most study areas (p < 0.05) with exception of the Gulf of Mexico where a strong morphometric cline was found. Possible explanations for the observed differences are related to environmental, biological and evolutionary processes. Shape distinction between dorsal fins from the Pacific and those from the Gulf of California were consistent with previously reported differences in skull morphometrics and genetics. Although the functional advantages of dorsal fin shape remains to be assessed, it is not unlikely that over a wide range of environments, fin shape may represent a trade-off among thermoregulatory capacity, hydrodynamic performance and the swimming/hunting behavior of the species. PMID:28626607

Air Mass Factor Formulation for Spectroscopic Measurements from Satellites: Application to Formaldehyde Retrievals from the Global Ozone Monitoring Experiment

NASA Technical Reports Server (NTRS)

Palmer, Paul I.; Jacob, Daniel J.; Chance, Kelly; Martin, Randall V.; Spurr, Robert J. D.; Kurosu, Thomas P.; Bey, Isabelle; Yantosca, Robert; Fiore, Arlene; Li, Qinbin

2004-01-01

We present a new formulation for the air mass factor (AMF) to convert slant column measurements of optically thin atmospheric species from space into total vertical columns. Because of atmospheric scattering, the AMF depends on the vertical distribution of the species. We formulate the AMF as the integral of the relative vertical distribution (shape factor) of the species over the depth of the atmosphere, weighted by altitude-dependent coefficients (scattering weights) computed independently from a radiative transfer model. The scattering weights are readily tabulated, and one can then obtain the AMF for any observation scene by using shape factors from a three dimensional (3-D) atmospheric chemistry model for the period of observation. This approach subsequently allows objective evaluation of the 3-D model with the observed vertical columns, since the shape factor and the vertical column in the model represent two independent pieces of information. We demonstrate the AMF method by using slant column measurements of formaldehyde at 346 nm from the Global Ozone Monitoring Experiment satellite instrument over North America during July 1996. Shape factors are cumputed with the Global Earth Observing System CHEMistry (GEOS-CHEM) global 3-D model and are checked for consistency with the few available aircraft measurements. Scattering weights increase by an order of magnitude from the surface to the upper troposphere. The AMFs are typically 20-40% less over continents than over the oceans and are approximately half the values calculated in the absence of scattering. Model-induced errors in the AMF are estimated to be approximately 10%. The GEOS-CHEM model captures 50% and 60% of the variances in the observed slant and vertical columns, respectively. Comparison of the simulated and observed vertical columns allows assessment of model bias.

Evaluation of the in-service safety performance of safety-shape and vertical concrete barriers.

DOT National Transportation Integrated Search

2011-12-16

Roadside concrete barriers have been widely used to protect errant motorists from hitting : roadside hazards or obstacles. Two concrete barrier profiles, vertical and safety-shape, have been used : for this purpose. The safety-shape profile has been ...

Apparatus and system for multivariate spectral analysis

DOEpatents

Keenan, Michael R.; Kotula, Paul G.

2003-06-24

An apparatus and system for determining the properties of a sample from measured spectral data collected from the sample by performing a method of multivariate spectral analysis. The method can include: generating a two-dimensional matrix A containing measured spectral data; providing a weighted spectral data matrix D by performing a weighting operation on matrix A; factoring D into the product of two matrices, C and S.sup.T, by performing a constrained alternating least-squares analysis of D=CS.sup.T, where C is a concentration intensity matrix and S is a spectral shapes matrix; unweighting C and S by applying the inverse of the weighting used previously; and determining the properties of the sample by inspecting C and S. This method can be used by a spectrum analyzer to process X-ray spectral data generated by a spectral analysis system that can include a Scanning Electron Microscope (SEM) with an Energy Dispersive Detector and Pulse Height Analyzer.

Research on conformal dome of Karman-curve shape

NASA Astrophysics Data System (ADS)

Zhang, Yunqiang; Chang, Jun; Niu, Yajun

2018-01-01

Because the conformal optical technology can obviously improve the aerodynamic performance of the infrared guidance missile, it has been studied deeply in recent years. By comparing the performance of the missiles with conformal dome and conventional missiles, the advantages of the conformal optical technology are demonstrated in the maneuverability and stealth of the missile. At present, the study of conformal optical systems focuses on ellipsoid or quadratic curve types. But in actual use, the dome using these curves is not the best choice. In this paper, the influence of different shape of the dome on aerodynamic performance, aerodynamic heating, internal space volume and other properties is discussed. The result shows infrared optical system with conformal dome of Karman-curve shape has a good application prospect, is the future direction of development. Finally, the difficult problems of conformal dome of Karman-curve shape are discussed.

Gender differences in colour naming performance for gender specific body shape images.

PubMed

Elliman, N A; Green, M W; Wan, W K

1998-03-01

Males are increasingly subjected to pressures to conform to aesthetic body stereotypes. There is, however, comparatively little published research on the aetiology of male body shape concerns. Two experiments are presented, which investigate the relationship between gender specific body shape concerns and colour-naming performance. Each study comprised a between subject design, in which each subject was tested on a single occasion. A pictorial version of a modified Stroop task was used in both studies. Subjects colour-named gender specific obese and thin body shape images and semantically homogeneous neutral images (birds) presented in a blocked format. The first experiment investigated female subjects (N = 68) and the second investigated males (N = 56). Subjects also completed a self-report measure of eating behaviour. Currently dieting female subjects exhibited significant colour-naming differences between obese and neutral images. A similar pattern of colour-naming performance was found to be related to external eating in the male subjects.

Load Disaggregation Technologies: Real World and Laboratory Performance

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

Mayhorn, Ebony T.; Sullivan, Greg P.; Petersen, Joseph M.

Low cost interval metering and communication technology improvements over the past ten years have enabled the maturity of load disaggregation (or non-intrusive load monitoring) technologies to better estimate and report energy consumption of individual end-use loads. With the appropriate performance characteristics, these technologies have the potential to enable many utility and customer facing applications such as billing transparency, itemized demand and energy consumption, appliance diagnostics, commissioning, energy efficiency savings verification, load shape research, and demand response measurement. However, there has been much skepticism concerning the ability of load disaggregation products to accurately identify and estimate energy consumption of end-uses; whichmore » has hindered wide-spread market adoption. A contributing factor is that common test methods and metrics are not available to evaluate performance without having to perform large scale field demonstrations and pilots, which can be costly when developing such products. Without common and cost-effective methods of evaluation, more developed disaggregation technologies will continue to be slow to market and potential users will remain uncertain about their capabilities. This paper reviews recent field studies and laboratory tests of disaggregation technologies. Several factors are identified that are important to consider in test protocols, so that the results reflect real world performance. Potential metrics are examined to highlight their effectiveness in quantifying disaggregation performance. This analysis is then used to suggest performance metrics that are meaningful and of value to potential users and that will enable researchers/developers to identify beneficial ways to improve their technologies.« less

Structural, optical, and improved field-emission properties of tetrapod-shaped Sn-doped ZnO nanostructures synthesized via thermal evaporation.

PubMed

Zhou, Xiongtu; Lin, Tihang; Liu, Yuhui; Wu, Chaoxing; Zeng, Xiangyao; Jiang, Dong; Zhang, Yong-ai; Guo, Tailiang

2013-10-23

High-quality tetrapod-shaped Sn-doped ZnO (T-SZO) nanostructures have been successfully synthesized via the thermal evaporation of mixed Zn and Sn powder. The effects of the Sn dopant on the morphology, microstructure, optical, and field-emission (FE) properties of T-SZO were investigated. It was found that the growth direction of the legs of T-SZO is parallel to the [0001] crystal c-axis direction and that the incorporation of Sn in the ZnO matrix increases the aspect ratio of the tetrapods, leads to blue shift in the UV region, and considerably improves the FE performance. The results also show that tetrapod cathodes with around a 0.84 atom % Sn dosage have the best FE properties, with a turn-on field of 1.95 V/μm, a current density of 950 μA/cm2 at a field of 4.5 V/μm, and a field-enhancement factor as high as 9556.

Processing and Structural Advantages of the Sylramic-iBN SiC Fiber for SiC/SiC Components

NASA Technical Reports Server (NTRS)

Yun, H. M.; Dicarlo, J. A.; Bhatt, R. T.; Hurst, J. B.

2008-01-01

The successful high-temperature application of complex-shaped SiC/SiC components will depend on achieving as high a fraction of the as-produced fiber strength as possible during component fabrication and service. Key issues center on a variety of component architecture, processing, and service-related factors that can reduce fiber strength, such as fiber-fiber abrasion during architecture shaping, surface chemical attack during interphase deposition and service, and intrinsic flaw growth during high-temperature matrix formation and composite creep. The objective of this paper is to show that the NASA-developed Sylramic-iBN SiC fiber minimizes many of these issues for state-of-the-art melt-infiltrated (MI) SiC/BN/SiC composites. To accomplish this, data from various mechanical tests are presented that compare how different high performance SiC fiber types retain strength during formation of complex architectures, during processing of BN interphases and MI matrices, and during simulated composite service at high temperatures.

[The genetic component of chronic respiratory diseases in workers of foundry productions].

PubMed

Loskutov, D V; Khamitova, R Ya

Review of the literature shows that currently there is an accumulation of data on the genetic determination of individual susceptibility to adverse industrial factors. Material of the research were high molecular DNA samples isolated from epithelial mouth scrapings in 99 foundry workers. Study of polymorphic variants of interleukin genes was performed by means of the analysis ofproducts of amplification of specific regions of the genome. Homozygous genotype TNF-a (-308A/G) was established to increase the relative risk of shaping of chronic respiratory diseases: with AA alleles - by 6.4 times and GG alleles - by 2.4 times, while the heterozygous genotype (AG) decreases - by 1. 9 times. Polymorphism of gene IL-1β (+3953 T / C) had no significance for the development of respiratory disease. Genotyping interleukins, involved in the inflammatory responses of the bronchopulmonary tract, can be considered as an element ofprimary prevention in industries with a high risk for shaping of respiratory diseases.

Real-time motion compensated patient positioning and non-rigid deformation estimation using 4-D shape priors.

PubMed

Wasza, Jakob; Bauer, Sebastian; Hornegger, Joachim

2012-01-01

Over the last years, range imaging (RI) techniques have been proposed for patient positioning and respiration analysis in motion compensation. Yet, current RI based approaches for patient positioning employ rigid-body transformations, thus neglecting free-form deformations induced by respiratory motion. Furthermore, RI based respiration analysis relies on non-rigid registration techniques with run-times of several seconds. In this paper we propose a real-time framework based on RI to perform respiratory motion compensated positioning and non-rigid surface deformation estimation in a joint manner. The core of our method are pre-procedurally obtained 4-D shape priors that drive the intra-procedural alignment of the patient to the reference state, simultaneously yielding a rigid-body table transformation and a free-form deformation accounting for respiratory motion. We show that our method outperforms conventional alignment strategies by a factor of 3.0 and 2.3 in the rotation and translation accuracy, respectively. Using a GPU based implementation, we achieve run-times of 40 ms.

Real scale experimental study for performance evaluation of unidirectional air diffuser perforated panels

NASA Astrophysics Data System (ADS)

Tăcutu, Laurenţiu; Nastase, Ilinca; Iordache, Vlad; Catalina, Tiberiu; Croitoru, Cristiana Verona

2018-02-01

Nowadays, there is an increasing emphasis on indoor air quality due to technological evolution and the fact that people spend most of the time in enclosed spaces. Also, energy efficiency is another related factor that gains more and more attention. Improving air distribution in an enclosure can lead to achieve these goals. This improvement can be done by adjustingthe air terminals position, theredimensions or the air diffuser perforations. The paper presents the study of 8 types of panels with different perforations shapes. The systems were characterized by flow, pressure loss and noise. Usualand special geometries were chosen, all having the same flowsurface. The perforated panels were mounted in a unidirectional air flow (UAF)diffuser, also called a laminar air flow (LAF)diffuser, that is placed in a real scale operating room (OR) in our laboratory.The purpose of this study is to determine whether changing the shape in the perforated panels can improve the technical parameters of the diffuser.

Wind tunnel evaluation of air-foil performance using simulated ice shapes

NASA Technical Reports Server (NTRS)

Bragg, M. B.; Zaguli, R. J.; Gregorek, G. M.

1982-01-01

A two-phase wind tunnel test was conducted in the 6 by 9 foot Icing Research Tunnel (IRT) at NASA Lewis Research Center to evaluate the effect of ice on the performance of a full scale general aviation wing. In the first IRT tests, rime and glaze shapes were carefully documented as functions of angle of attack and free stream conditions. Next, simulated ice shapes were constructed for two rime and two glaze shapes and used in the second IRT tunnel entry. The ice shapes and the clean airfoil were tapped to obtain surface pressures and a probe used to measure the wake characteristics. These data were recorded and processed, on-line, with a minicomputer/digital data acquisition system. The effect of both rime and glaze ice on the pressure distribution, Cl, Cd, and Cm are presented.

Axi-symmetric patterns of active polar filaments on spherical and composite surfaces

NASA Astrophysics Data System (ADS)

Srivastava, Pragya; Rao, Madan

2014-03-01

Experiments performed on Fission Yeast cells of cylindrical and spherical shapes, rod-shaped bacteria and reconstituted cylindrical liposomes suggest the influence of cell geometry on patterning of cortical actin. A theoretical model based on active hydrodynamic description of cortical actin that includes curvature-orientation coupling predicts spontaneous formation of acto-myosin rings, cables and nodes on cylindrical and spherical geometries [P. Srivastava et al, PRL 110, 168104(2013)]. Stability and dynamics of these patterns is also affected by the cellular shape and has been observed in experiments performed on Fission Yeast cells of spherical shape. Motivated by this, we study the stability and dynamics of axi-symmetric patterns of active polar filaments on the surfaces of spherical, saddle shaped and conical geometry and classify the stable steady state patterns on these surfaces. Based on the analysis of the fluorescence images of Myosin-II during ring slippage we propose a simple mechanical model for ring-sliding based on force balance and make quantitative comparison with the experiments performed on Fission Yeast cells. NSF Grant DMR-1004789 and Syracuse Soft Matter Program.

Realtime Reconstruction of an Animating Human Body from a Single Depth Camera.

PubMed

Chen, Yin; Cheng, Zhi-Quan; Lai, Chao; Martin, Ralph R; Dang, Gang

2016-08-01

We present a method for realtime reconstruction of an animating human body,which produces a sequence of deforming meshes representing a given performance captured by a single commodity depth camera. We achieve realtime single-view mesh completion by enhancing the parameterized SCAPE model.Our method, which we call Realtime SCAPE, performs full-body reconstruction without the use of markers.In Realtime SCAPE, estimations of body shape parameters and pose parameters, needed for reconstruction, are decoupled. Intrinsic body shape is first precomputed for a given subject, by determining shape parameters with the aid of a body shape database. Subsequently, per-frame pose parameter estimation is performed by means of linear blending skinning (LBS); the problem is decomposed into separately finding skinning weights and transformations. The skinning weights are also determined offline from the body shape database,reducing online reconstruction to simply finding the transformations in LBS. Doing so is formulated as a linear variational problem;carefully designed constraints are used to impose temporal coherence and alleviate artifacts. Experiments demonstrate that our method can produce full-body mesh sequences with high fidelity.

Variability of O3 and NO2 profile shapes during DISCOVER-AQ: Implications for satellite observations and comparisons to model-simulated profiles

NASA Astrophysics Data System (ADS)

Flynn, Clare Marie; Pickering, Kenneth E.; Crawford, James H.; Weinheimer, Andrew J.; Diskin, Glenn; Thornhill, K. Lee; Loughner, Christopher; Lee, Pius; Strode, Sarah A.

2016-12-01

To investigate the variability of in situ profile shapes under a variety of meteorological and pollution conditions, results are presented of an agglomerative hierarchical cluster analysis of the in situ O3 and NO2 profiles for each of the four campaigns of the NASA DISCOVER-AQ mission. Understanding the observed profile variability for these trace gases is useful for understanding the accuracy of the assumed profile shapes used in satellite retrieval algorithms as well as for understanding the correlation between satellite column observations and surface concentrations. The four campaigns of the DISCOVER-AQ mission took place in Maryland during July 2011, the San Joaquin Valley of California during January-February 2013, the Houston, Texas, metropolitan region during September 2013, and the Denver-Front Range region of Colorado during July-August 2014. Several distinct profile clusters emerged for the California, Texas, and Colorado campaigns for O3, indicating significant variability of O3 profile shapes, while the Maryland campaign presented only one distinct O3 cluster. In contrast, very few distinct profile clusters emerged for NO2 during any campaign for this particular clustering technique, indicating the NO2 profile behavior was relatively uniform throughout each campaign. However, changes in NO2 profile shape were evident as the boundary layer evolved through the day, but they were apparently not significant enough to yield more clusters. The degree of vertical mixing (as indicated by temperature lapse rate) associated with each cluster exerted an important influence on the shapes of the median cluster profiles for O3, as well as impacted the correlations between the associated column and surface data for each cluster for O3. The correlation analyses suggest satellites may have the best chance to relate to surface O3 under the conditions encountered during the Maryland campaign Clusters 1 and 2, which include deep, convective boundary layers and few interruptions to this connection from complex meteorology, chemical environments, or orography. The regional CMAQ model captured the shape factors for O3, and moderately well captured the NO2 shape factors, for the conditions associated with the Maryland campaign, suggesting that a regional air quality model may adequately specify a priori profile shapes for remote sensing retrievals. CMAQ shape factor profiles were not as well represented for the other regions.

Neutrino mass hierarchy and precision physics with medium-baseline reactors: Impact of energy-scale and flux-shape uncertainties

NASA Astrophysics Data System (ADS)

Capozzi, F.; Lisi, E.; Marrone, A.

2015-11-01

Nuclear reactors provide intense sources of electron antineutrinos, characterized by few-MeV energy E and unoscillated spectral shape Φ (E ). High-statistics observations of reactor neutrino oscillations over medium-baseline distances L ˜O (50 ) km would provide unprecedented opportunities to probe both the long-wavelength mass-mixing parameters (δ m2 and θ12) and the short-wavelength ones (Δ mee 2 and θ13), together with the subtle interference effects associated with the neutrino mass hierarchy (either normal or inverted). In a given experimental setting—here taken as in the JUNO project for definiteness—the achievable hierarchy sensitivity and parameter accuracy depend not only on the accumulated statistics but also on systematic uncertainties, which include (but are not limited to) the mass-mixing priors and the normalizations of signals and backgrounds. We examine, in addition, the effect of introducing smooth deformations of the detector energy scale, E →E'(E ), and of the reactor flux shape, Φ (E )→Φ'(E ), within reasonable error bands inspired by state-of-the-art estimates. It turns out that energy-scale and flux-shape systematics can noticeably affect the performance of a JUNO-like experiment, both on the hierarchy discrimination and on precision oscillation physics. It is shown that a significant reduction of the assumed energy-scale and flux-shape uncertainties (by, say, a factor of 2) would be highly beneficial to the physics program of medium-baseline reactor projects. Our results also shed some light on the role of the inverse-beta decay threshold, of geoneutrino backgrounds, and of matter effects in the analysis of future reactor oscillation data.

General purpose pulse shape analysis for fast scintillators implemented in digital readout electronics

NASA Astrophysics Data System (ADS)

Asztalos, Stephen J.; Hennig, Wolfgang; Warburton, William K.

2016-01-01

Pulse shape discrimination applied to certain fast scintillators is usually performed offline. In sufficiently high-event rate environments data transfer and storage become problematic, which suggests a different analysis approach. In response, we have implemented a general purpose pulse shape analysis algorithm in the XIA Pixie-500 and Pixie-500 Express digital spectrometers. In this implementation waveforms are processed in real time, reducing the pulse characteristics to a few pulse shape analysis parameters and eliminating time-consuming waveform transfer and storage. We discuss implementation of these features, their advantages, necessary trade-offs and performance. Measurements from bench top and experimental setups using fast scintillators and XIA processors are presented.

Micropore Geometry Manipulation by Macroscopic Deformation Based on Shape Memory Effect in Porous PLLA Membrane and its Enhanced Separation Performance.

PubMed

Zhao, Jingxin; Yang, Qiucheng; Wang, Tao; Wang, Lian; You, Jichun; Li, Yongjin

2017-12-20

An effective strategy to tailor the microporous structures has been developed based on the shape memory effect in porous poly(l-lactic acid) membranes in which tiny crystals and amorphous matrix play the roles of shape-fixed phase and reversible-phase, respectively. Our results indicate that not only PLLA membranes but micropores exhibit shape memory properties. The proportional deformations on two scales have been achieved by uniaxial or biaxial tension, providing a facile way to manipulate continuously the size and the orientation degree of pores on microscale. The enhanced separation performance has been validated by taking polystyrene colloids with varying diameters as an example.

Contact resistance reduction of ZnO thin film transistors (TFTs) with saw-shaped electrode.

PubMed

Park, Woojin; Shaikh, Sohail F; Min, Jung-Wook; Lee, Sang Kyung; Lee, Byoung Hun; Hussain, Muhammad M

2018-08-10

We report on a saw-shaped electrode architecture ZnO thin film transistor (TFT), which effectively increases the channel width. The contact line of the saw-shaped electrode is almost twice as long at the contact metal/ZnO channel junction. We experimentally observed an enhancement in the output drive current by 50% and a reduction in the contact resistance by over 50%, when compared to a typically shaped electrode ZnO TFT consuming the same chip area. This performance enhancement is attributed to the extension of the channel width. This technique can contribute to device performance enhancement, and in particular reduce the contact resistance, which is a serious challenge.

Bistable Microvalve For Use With Microcatheter System

DOEpatents

Seward, Kirk Patrick

2003-12-16

A bistable microvalve of shape memory material is operatively connected to a microcatheter. The bistable microvalve includes a tip that can be closed off until it is in the desired position. Once it is in position it can be opened and closed. The system uses heat and pressure to open and close the microvalve. The shape memory material will change stiffness and shape when heated above a transition temperature. The shape memory material is adapted to move from a first shape to a second shape, either open or closed, where it can perform a desired function.

Bistable microvalve and microcatheter system

DOEpatents

Seward, Kirk Patrick

2003-05-20

A bistable microvalve of shape memory material is operatively connected to a microcatheter. The bistable microvalve includes a tip that can be closed off until it is in the desired position. Once it is in position it can opened and closed. The system uses heat and pressure to open and close the microvalve. The shape memory material will change stiffness and shape when heated above a transition temperature. The shape memory material is adapted to move from a first shape to a second shape, either open or closed, where it can perform a desired function.

Effect of ceramic membrane channel geometry and uniform transmembrane pressure on limiting flux and serum protein removal during skim milk microfiltration.

PubMed

Adams, Michael C; Hurt, Emily E; Barbano, David M

2015-11-01

Our objectives were to determine the effects of a ceramic microfiltration (MF) membrane's retentate flow channel geometry (round or diamond-shaped) and uniform transmembrane pressure (UTP) on limiting flux (LF) and serum protein (SP) removal during skim milk MF at a temperature of 50°C, a retentate protein concentration of 8.5%, and an average cross-flow velocity of 7 m·s(-1). Performance of membranes with round and diamond flow channels was compared in UTP mode. Performance of the membrane with round flow channels was compared with and without UTP. Using UTP with round flow channel MF membranes increased the LF by 5% when compared with not using UTP, but SP removal was not affected by the use of UTP. Using membranes with round channels instead of diamond-shaped channels in UTP mode increased the LF by 24%. This increase was associated with a 25% increase in Reynolds number and can be explained by lower shear at the vertices of the diamond-shaped channel's surface. The SP removal factor of the diamond channel system was higher than the SP removal factor of the round channel system below the LF. However, the diamond channel system passed more casein into the MF permeate than the round channel system. Because only one batch of each membrane was tested in our study, it was not possible to determine if the differences in protein rejection between channel geometries were due to the membrane design or random manufacturing variation. Despite the lower LF of the diamond channel system, the 47% increase in membrane module surface area of the diamond channel system produced a modular permeate removal rate that was at least 19% higher than the round channel system. Consequently, using diamond channel membranes instead of round channel membranes could reduce some of the costs associated with ceramic MF of skim milk if fewer membrane modules could be used to attain the required membrane area. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

M-I-S solar cell - Theory and experimental results

NASA Technical Reports Server (NTRS)

Childs, R.; Fortuna, J.; Geneczko, J.; Fonash, S. J.

1976-01-01

The paper presents an operating-mode analysis of an MIS solar cell and discusses the advantages which can arise as a result of the use of transport control, field shaping (increased n factor), and zero bias barrier height modification. It is noted that for an n-type semiconductor, it is relatively easy to obtain an enhanced n factor using acceptor-like states without an increase in diode saturation current, the converse being true for p-type semiconductors. Several MIS configurations are examined: an acceptor-like, localized state configuration producing field shaping and no change in diode saturation current, and acceptor-like localized configurations producing field shaping, with a decrease of diode saturation current, in one case, and an increase in the other.

Investigating in-field and out-of-field neutron contamination in high-energy medical linear accelerators based on the treatment factors of field size, depth, beam modifiers, and beam type.

PubMed

Biltekin, Fatih; Yeginer, Mete; Ozyigit, Gokhan

2015-07-01

We analysed the effects of field size, depth, beam modifier and beam type on the amount of in-field and out-of-field neutron contamination for medical linear accelerators (linacs). Measurements were carried out for three high-energy medical linacs of Elekta Synergy Platform, Varian Clinac DHX High Performance and Philips SL25 using bubble detectors. The photo-neutron measurements were taken in the first two linacs with 18 MV nominal energy, whereas the electro-neutrons were measured in the three linacs with 9 MeV, 10 MeV, 15 MeV and 18 MeV. The central neutron doses increased with larger field sizes as a dramatic drop off was observed in peripheral areas. Comparing with the jaws-shaped open-field of 10 × 10 cm, the motorised and physical wedges contributed to neutron contamination at central axis by 60% and 18%, respectively. The similar dose increment was observed in MLC-shaped fields. The contributions of MLCs were in the range of 55-59% and 19-22% in Elekta and Varian linacs comparing with 10 × 10 and 20 × 20 cm open fields shaped by the jaws, respectively. The neutron doses at shallow depths were found to be higher than the doses found at deeper regions. The electro-neutron dose at the 18 MeV energy was higher than the doses at the electron energies of 15 MeV and 9 MeV by a factor of 3 and 50, respectively. The photo- and electro-neutron dose should be taken into consideration in the radiation treatment with high photon and electron energies. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Colorimetric DNA detection of transgenic plants using gold nanoparticles functionalized with L-shaped DNA probes

NASA Astrophysics Data System (ADS)

Nourisaeid, Elham; Mousavi, Amir; Arpanaei, Ayyoob

2016-01-01

In this study, a DNA colorimetric detection system based on gold nanoparticles functionalized with L-shaped DNA probes was prepared and evaluated. We investigated the hybridization efficiency of the L-shaped probes and studied the effect of nanoparticle size and the L-shaped DNA probe length on the performance of the as-prepared system. Probes were attached to the surface of gold nanoparticles using an adenine sequence. An optimal sequence of 35S rRNA gene promoter from the cauliflower mosaic virus, which is frequently used in the development of transgenic plants, and the two complementary ends of this gene were employed as model target strands and probe molecules, respectively. The spectrophotometric properties of the as-prepared systems indicated that the large NPs show better changes in the absorption spectrum and consequently present a better performance. The results of this study revealed that the probe/Au-NPs prepared using a vertical spacer containing 5 thymine oligonucleotides exhibited a stronger spectrophotometric response in comparison to that of larger probes. These results in general indicate the suitable performance of the L-shaped DNA probe-functionalized Au-NPs, and in particular emphasize the important role of the gold nanoparticle size and length of the DNA probes in enhancing the performance of such a system.

Design of a metasurface-based dual-band Terahertz perfect absorber with very high Q-factors for sensing applications

NASA Astrophysics Data System (ADS)

Janneh, M.; De Marcellis, A.; Palange, E.; Tenggara, A. T.; Byun, D.

2018-06-01

We report on a novel very high Q-factor dual-band Terahertz perfect absorber composed of a metasurface located on top of a flexible polyimide spacer deposited on a silver ground layer. The metasurface is a 2D-array of plasmonic nanoantennas with the shape of two concentric square rings and a cylinder positioned at their centre. By performing numerical simulations, we studied the polarisation insensitive electromagnetic response of the absorber for incident angles varying from 0° up to ±30°. The two resonant modes centred at f1 = 1.80 THz and f2 = 2.26 THz have Q-factors Q(f1) = 120 and Q(f2) = 94 and absorption coefficients A(f1) = 99 . 8 % and A(f2) = 99 . 6%. Moreover, we investigated how the resonant mode frequencies change with the refractive index and thickness of transparent analytes adsorbed on the metasurface. In terms of the Refractive Index Units (RIU), we obtained sensitivities equal to 187.5 GHz/RIU and 360 GHz/RIU for the f1 and f2 resonance frequencies, respectively, and figure of merits up to FOM = 19 . 1 and FOM∗ = 431. These results make the dual-band absorber to be employed as a sensing device able to detect the presence and/or the physical/chemical modifications of the adsorbed analytes. Moreover, we investigated the dependence of the sensitivity as a function of slight modifications of the metasurface nanoantenna shape, demonstrating that a more homogeneous distribution of the electric field intensity on the metasurface improves the sensitivity of the absorber without affecting the Q-factors.

Standardized laryngeal videostroboscopic rating: differences between untrained and trained male and female subjects, and effects of varying sound intensity, fundamental frequency, and age.

PubMed

Sulter, A M; Schutte, H K; Miller, D G

1996-06-01

To determine the influence of the factors gender, vocal training, sound intensity, pitch, and aging on vocal function, videolaryngostroboscopic images of 214 subjects, subdivided according to gender and status of vocal training, were evaluated by three judges with standardized rating scales, comprising aspects of laryngeal appearance (larynx/pharynx ratio; epiglottal shape; asymmetry arytenoid region; compensatory adjustments; thickness, width, length, and elasticity of vocal folds) and glottal functioning (amplitudes of excursion; duration, percentage, and type of vocal fold closure; phase differences; location of glottal chink). The video registrations were made while the subjects performed a set of phonatory tasks, comprising the utterance of the vowel /i/ at three levels of both fundamental frequency and sound intensity. Analysis of the rating scales showed generally sufficient agreement among judges. With the exception of more frequently observed complete closure and lateral phase differences of vocal fold excursions in trained subjects, no further differences were established between untrained and trained subjects. With an alpha level of p = 0.005, men differed from women with respect to laryngeal appearance (larynx/pharynx ratio, compensatory adjustments, and the presence of omega and deviant-shaped epiglottises), and their vocal folds were rated thicker in the vertical dimension, smaller in the lateral dimension, longer, and more tense, with smaller amplitudes of excursion during vibration. Glottal closure in male subjects was rated more complete, but briefer in duration. Significant effects of the factors pitch, sound intensity, and age on vocal fold appearance and glottal functioning were ascertained. Awareness of the influence of these factors, as well as the factor gender, on the rated scales is essential for an adequate evaluation of laryngostroboscopic images.

Bilingual children's long-term outcomes in English as a second language: language environment factors shape individual differences in catching up with monolinguals.

PubMed

Paradis, Johanne; Jia, Ruiting

2017-01-01

Bilingual children experience more variation in their language environment than monolingual children and this impacts their rate of language development with respect to monolinguals. How long it takes for bilingual children learning English as a second language (L2) to display similar abilities to monolingual age-peers has been estimated to be 4-6 years, but conflicting findings suggest that even 6 years in school is not enough. Most studies on long-term L2 development have focused on just one linguistic sub-domain, vocabulary, and have not included multiple individual difference factors. For the present study, Chinese first language-English L2 children were given standardized measures of vocabulary, grammar and global comprehension every year from 4 ½ to 6 ½ years of English in school (ages 8½ to 10½); language environment factors were obtained through an extensive parent questionnaire. Children converged on monolingual norms differentially according to the test, with the majority of children reaching monolingual levels of performance on the majority of tests by 5 ½ years of English exposure. Individual differences in outcomes were predicted by length of English exposure, mother's education, mother's English fluency, child's use of English in the home, richness/quality of the English input outside school and age of arrival in Canada. In sum, the timeframe for bilinguals to catch up to monolinguals depends on linguistic sub-domain, task difficulty and on individual children's language environment, making 4-6 years an approximate estimate only. This study also shows that language environment factors shape not only early-stage but also late-stage bilingual development. © 2016 John Wiley & Sons Ltd.

The von Mises stress distribution on the surface of UHMWPE with texture-shaped variation in the presence of normal load and dry sliding contact

NASA Astrophysics Data System (ADS)

Lestari, W. D.; Jamari, J.; Bayuseno, A. P.

2017-04-01

The texture shapes play a key role in the tribological performance of the surface material. This paper presents a study on the use of the 3D finite element method for surface stress analysis on the different texture shape under load and dry sliding contact. The five texture-shaped model was investigated in this work, namely square, circle, ellipse, triangle, and chevron. The result shown that the square shape has the highest value of von Mises resultant stress under static load. In contrast, the dry sliding contact on the triangle shape provided the highest von Mises stress distribution. The lowest value of von Mises stress can be found in the texture pattern of circle, square, and chevron under influence of load for 17 N, 30 N, and 50 N, respectively. Those texture patterns applied to surface of Ultra High Molecular Weight Polyethylene (UHMWPE) may have a strong effect on the reduction of wear rate and enhance tribological performance.

Individual differences in dopamine level modulate the ego depletion effect.

PubMed

Dang, Junhua; Xiao, Shanshan; Liu, Ying; Jiang, Yumeng; Mao, Lihua

2016-01-01

Initial exertion of self-control impairs subsequent self-regulatory performance, which is referred to as the ego depletion effect. The current study examined how individual differences in dopamine level, as indexed by eye blink rate (EBR), would moderate ego depletion. An inverted-U-shaped relationship between EBR and subsequent self-regulatory performance was found when participants initially engaged in self-control but such relationship was absent in the control condition where there was no initial exertion, suggesting individuals with a medium dopamine level may be protected from the typical ego depletion effect. These findings are consistent with a cognitive explanation which considers ego depletion as a phenomenon similar to "switch costs" that would be neutralized by factors promoting flexible switching. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of heat treatment on shape-setting and non-linearmechanical properties of Nitinol stent

NASA Astrophysics Data System (ADS)

Liu, Xiaopeng; Wang, Yinong; Qi, Min; Yang, Dazhi

2007-07-01

NiTi shape memory alloy is a temperature sensitive material with non-linear mechanical properties and good biocompatibility, which can be used for medical devices such as stent, catheter guide wire and orthodontic wire. The majority of nitinol stents are of the self-expanding type basing on the superelasticity. Nitinol stents are shape set into the open condition and compressed and inserted into the delivery catheter. Additional the shape-setting treatment can be used as a tool to accurately tune the transformation temperatures and mechanical properties. In this study, different heat treatments have been performed on the Ti-50.7at%Ni alloy wires. And results of shape-setting, austenite transformation finish temperature and non-linear mechanical property of NiTi shape memory alloy at body temperature have been investigated. The experimental results show that the proper shape-setting temperature should be chosen between 450-550 °C. And the shape-setting results were stabilization when the NiTi wires were constrain-treated at 500 and 550°C and ageing time longer than 10 minutes. The austenite finish temperatures increased with ageing time and increased first and then decreased with ageing temperature. The peak values were obtained at 400°C. When the heat treatments was performed at the same temperature, both the upper plateau stresses and lower plateau stresses decreased with the ageing time. Most of treated nitinol wires owned good recovery ability at body temperature and the permanent sets were less than 0.05% when short time ageing treatment was performed at 500°C.

Software Performs Complex Design Analysis

NASA Technical Reports Server (NTRS)

2008-01-01

Designers use computational fluid dynamics (CFD) to gain greater understanding of the fluid flow phenomena involved in components being designed. They also use finite element analysis (FEA) as a tool to help gain greater understanding of the structural response of components to loads, stresses and strains, and the prediction of failure modes. Automated CFD and FEA engineering design has centered on shape optimization, which has been hindered by two major problems: 1) inadequate shape parameterization algorithms, and 2) inadequate algorithms for CFD and FEA grid modification. Working with software engineers at Stennis Space Center, a NASA commercial partner, Optimal Solutions Software LLC, was able to utilize its revolutionary, one-of-a-kind arbitrary shape deformation (ASD) capability-a major advancement in solving these two aforementioned problems-to optimize the shapes of complex pipe components that transport highly sensitive fluids. The ASD technology solves the problem of inadequate shape parameterization algorithms by allowing the CFD designers to freely create their own shape parameters, therefore eliminating the restriction of only being able to use the computer-aided design (CAD) parameters. The problem of inadequate algorithms for CFD grid modification is solved by the fact that the new software performs a smooth volumetric deformation. This eliminates the extremely costly process of having to remesh the grid for every shape change desired. The program can perform a design change in a markedly reduced amount of time, a process that would traditionally involve the designer returning to the CAD model to reshape and then remesh the shapes, something that has been known to take hours, days-even weeks or months-depending upon the size of the model.

Modeling the interaction of ultrasound with pores

NASA Technical Reports Server (NTRS)

Lu, Yichi; Wadley, Haydn N. G.; Parthasarathi, Sanjai

1991-01-01

Factors that affect ultrasonic velocity sensing of density during consolidation of metal powders are examined. A comparison is made between experimental results obtained during the final stage of densification and the predictions of models that assume either a spherical or a spheroidal pore shape. It is found that for measurements made at low frequencies during the final stage of densification, relative density (pore fraction) and pore shape are the two most important factors determining the ultrasonic velocity, the effect of pore size is negligible.

Technology optimization techniques for multicomponent optical band-pass filter manufacturing

NASA Astrophysics Data System (ADS)

Baranov, Yuri P.; Gryaznov, Georgiy M.; Rodionov, Andrey Y.; Obrezkov, Andrey V.; Medvedev, Roman V.; Chivanov, Alexey N.

2016-04-01

Narrowband optical devices (like IR-sensing devices, celestial navigation systems, solar-blind UV-systems and many others) are one of the most fast-growing areas in optical manufacturing. However, signal strength in this type of applications is quite low and performance of devices depends on attenuation level of wavelengths out of operating range. Modern detectors (photodiodes, matrix detectors, photomultiplier tubes and others) usually do not have required selectivity or have higher sensitivity to background spectrum at worst. Manufacturing of a single component band-pass filter with high attenuation level of wavelength is resource-intensive task. Sometimes it's not possible to find solution for this problem using existing technologies. Different types of filters have technology variations of transmittance profile shape due to various production factors. At the same time there are multiple tasks with strict requirements for background spectrum attenuation in narrowband optical devices. For example, in solar-blind UV-system wavelengths above 290-300 nm must be attenuated by 180dB. In this paper techniques of multi-component optical band-pass filters assembly from multiple single elements with technology variations of transmittance profile shape for optimal signal-tonoise ratio (SNR) were proposed. Relationships between signal-to-noise ratio and different characteristics of transmittance profile shape were shown. Obtained practical results were in rather good agreement with our calculations.

Effect of stern hull shape on turning circle of ships

NASA Astrophysics Data System (ADS)

Jaswar, Maimun, A.; Wahid, M. A.; Priyanto, A.; Zamani, Pauzi, Saman

2012-06-01

Many factors such as: stern hull shape, length, draught, trim, propulsion system and external forces affecting the drift angle influence rate of turn and size of turning circle of ships. This paper discusses turning circle characteristics of U and V stern hull shape of Very Large Crude Oil Carrier (VLCC) ships. The ships have same principal dimension such as length, beam, and draught. The turning circle characteristics of the VLCC ships are simulated at 35 degree of rudder angle. In the analysis, firstly, turning circle performance of U-type VLCC ship is simulated. In the simulation, initial ship speed is determined using given power and rpm. Hydrodynamic derivatives coefficients are determined by including effect of fullness of aft run. Using the obtained, speed and hydrodynamic coefficients, force and moment acting on hull, force and moment induced by propeller, force and moment induced by rudder are determined. Finally, ship trajectory, ratio of speed, yaw angle and drift angle are determined. Results of simulation results of the VLCC ship are compared with the experimental one as validation. Using the same method, V-type VLCC is simulated and the simulation results are compared with U-type VLCC ship. Results shows the turning circle of U-type is larger than V-type due to effect stern hul results of simulation are.

Optimized mirror shape tuning using beam weightings based on distance, angle of incidence, reflectivity, and power.

PubMed

Goldberg, Kenneth A; Yashchuk, Valeriy V

2016-05-01

For glancing-incidence optical systems, such as short-wavelength optics used for nano-focusing, incorporating physical factors in the calculations used for shape optimization can improve performance. Wavefront metrology, including the measurement of a mirror's shape or slope, is routinely used as input for mirror figure optimization on mirrors that can be bent, actuated, positioned, or aligned. Modeling shows that when the incident power distribution, distance from focus, angle of incidence, and the spatially varying reflectivity are included in the optimization, higher Strehl ratios can be achieved. Following the works of Maréchal and Mahajan, optimization of the Strehl ratio (for peak intensity with a coherently illuminated system) occurs when the expectation value of the phase error's variance is minimized. We describe an optimization procedure based on regression analysis that incorporates these physical parameters. This approach is suitable for coherently illuminated systems of nearly diffraction-limited quality. Mathematically, this work is an enhancement of the methods commonly applied for ex situ alignment based on uniform weighting of all points on the surface (or a sub-region of the surface). It follows a similar approach to the optimization of apodized and non-uniformly illuminated optical systems. Significantly, it reaches a different conclusion than a more recent approach based on minimization of focal plane ray errors.

Significance of crown shape in the replacement of a central incisor with a single implant-supported crown.

PubMed

Gobbato, Luca; Paniz, Gianluca; Mazzocco, Fabio; Chierico, Andrea; Tsukiyama, Teppei; Levi, Paul A; Weisgold, Arnold S

2013-05-01

When utilizing a single implant-supported crown to replace a central incisor, understanding the final shape of the implant restoration is an important factor to help achieve a successful esthetic outcome. In today's dentistry, tooth shape is a critical factor when dental implant prostheses are considered in the esthetic zone. The major esthetic goal for this type of restoration is to achieve the closest possible symmetry with the adjacent tooth, both at the soft and at the hard tissue levels. The goal of this study was to objectively analyze the significance of natural crown shape when replacing a central incisor with a single implant-supported crown. In this study, we investigated the shape of the crowns of maxillary central incisors in 60 individuals who presented to our clinics with an untreatable central incisor. The presence of a dental diastema, "black triangle," presence or absence of gingival symmetry, and the presence or absence of dental symmetry were recorded in the pre- and postoperative photographs. Out of 60 patients, 33.3% had triangular-shaped crowns, 16.6% square/tapered, and 50% square-shaped crown form. After treatment was rendered, 65% of the triangular group, 40% of the square/tapered group, and 13.3% of the square group required an additional restoration on the adjacent central incisor in order to fulfill the esthetic needs of the patients. Data analysis revealed that if there is a "black triangle," a diastema, or presence of dental or gingival asymmetry, an additional restoration on the adjacent central incisor is often required in order to fulfill esthetic goals. The additional restoration is highly recommended in situations with a triangular crown shape, while it is suggested in cases of square/tapered and square tooth shapes in the presence of a dental diastema.

Shaping Gene Expression by Landscaping Chromatin Architecture: Lessons from a Master.

PubMed

Sartorelli, Vittorio; Puri, Pier Lorenzo

2018-05-19

Since its discovery as a skeletal muscle-specific transcription factor able to reprogram somatic cells into differentiated myofibers, MyoD has provided an instructive model to understand how transcription factors regulate gene expression. Reciprocally, studies of other transcriptional regulators have provided testable hypotheses to further understand how MyoD activates transcription. Using MyoD as a reference, in this review, we discuss the similarities and differences in the regulatory mechanisms employed by tissue-specific transcription factors to access DNA and regulate gene expression by cooperatively shaping the chromatin landscape within the context of cellular differentiation. Copyright © 2018 Elsevier Inc. All rights reserved.

Stress Intensity Factors of Semi-Circular Bend Specimens with Straight-Through and Chevron Notches

NASA Astrophysics Data System (ADS)

Ayatollahi, M. R.; Mahdavi, E.; Alborzi, M. J.; Obara, Y.

2016-04-01

Semi-circular bend specimen is one of the useful test specimens for determining fracture toughness of rock and geo-materials. Generally, in rock test specimens, initial cracks are produced in two shapes: straight-edge cracks and chevron notches. In this study, the minimum dimensionless stress intensity factors of semi-circular bend specimen (SCB) with straight-through and chevron notches are calculated. First, using finite element analysis, a suitable relation for the dimensionless stress intensity factor of SCB with straight-through crack is presented based on the normalized crack length and half-distance between supports. For evaluating the validity and accuracy of this relation, the obtained results are then compared with numerical and experimental results reported in the literature. Subsequently, by performing some experiments and also finite element analysis of the SCB specimen with chevron notch, the minimum dimensionless stress intensity factor of this specimen is obtained. Using the new equation for the dimensionless stress intensity factor of SCB with straight-through crack and an analytical method, i.e., Bluhm's slice synthesis method, the minimum (critical) dimensionless stress intensity factor of chevron notched semi-circular bend specimens is calculated. Good agreement is observed between the results of two mentioned methods.

Cosmological information in Gaussianized weak lensing signals

NASA Astrophysics Data System (ADS)

Joachimi, B.; Taylor, A. N.; Kiessling, A.

2011-11-01

Gaussianizing the one-point distribution of the weak gravitational lensing convergence has recently been shown to increase the signal-to-noise ratio contained in two-point statistics. We investigate the information on cosmology that can be extracted from the transformed convergence fields. Employing Box-Cox transformations to determine optimal transformations to Gaussianity, we develop analytical models for the transformed power spectrum, including effects of noise and smoothing. We find that optimized Box-Cox transformations perform substantially better than an offset logarithmic transformation in Gaussianizing the convergence, but both yield very similar results for the signal-to-noise ratio. None of the transformations is capable of eliminating correlations of the power spectra between different angular frequencies, which we demonstrate to have a significant impact on the errors in cosmology. Analytic models of the Gaussianized power spectrum yield good fits to the simulations and produce unbiased parameter estimates in the majority of cases, where the exceptions can be traced back to the limitations in modelling the higher order correlations of the original convergence. In the ideal case, without galaxy shape noise, we find an increase in the cumulative signal-to-noise ratio by a factor of 2.6 for angular frequencies up to ℓ= 1500, and a decrease in the area of the confidence region in the Ωm-σ8 plane, measured in terms of q-values, by a factor of 4.4 for the best performing transformation. When adding a realistic level of shape noise, all transformations perform poorly with little decorrelation of angular frequencies, a maximum increase in signal-to-noise ratio of 34 per cent, and even slightly degraded errors on cosmological parameters. We argue that to find Gaussianizing transformations of practical use, it will be necessary to go beyond transformations of the one-point distribution of the convergence, extend the analysis deeper into the non-linear regime and resort to an exploration of parameter space via simulations.

The viscoelastic effect in bending bucky-gel actuators

NASA Astrophysics Data System (ADS)

Kruusamäe, Karl; Mukai, Ken; Sugino, Takushi; Asaka, Kinji

2014-03-01

Electromechanically active polymers (EAP) are considered a good actuator candidate for a variety of reasons, e.g. they are soft, easy to miniaturize and operate without audible noise. The main structural component in EAPs is, as the name states, a type of deformable polymer. As polymers are known to exhibit a distinct mechanical response, the nature of polymer materials should never be neglected when characterizing and modeling the performance of EAP actuators. Bucky-gel actuators are a subtype of EAPs where ion-containing polymer membrane acts as an electronically insulating separator between two electrodes of carbon nanotubes and ionic liquid. In many occasions, the electrodes also contain polymer for the purpose of binding it together. Therefore, mechanically speaking, bucky-gel actuators are composite structures with layers of different mechanical nature. The viscoelastic response and the shape change property are perhaps the most characteristic effects in polymers. These effects are known to have high dependence on factors such as the type of polymer, the concentration of additives and the structural ratio of different layers. At the same time, most reports about optimization of EAP actuators describe the alteration of electromechanical performance dependent on the same factors. In this paper, the performance of bucky-gel actuators is measured as a function between the output force and bending deflection. It is observed that effective stiffness of these actuators depends on the input voltage. This finding is also supported by dynamic mechanical analysis which demonstrates that the viscoelastic response of bucky-gel laminate depends on both frequency and temperature. Moreover, the dynamic mechanical analysis reveals that in the range of standard operation temperatures, tested samples were in their glass transition region, which made it possible to alter their shape by using mechanical fixing. The mechanical fixity above 90% was obtained when high-frequency input signal was used to heat the bucky-gel sample.

Retrospective Attention Interacts with Stimulus Strength to Shape Working Memory Performance.

PubMed

Wildegger, Theresa; Humphreys, Glyn; Nobre, Anna C

2016-01-01

Orienting attention retrospectively to selective contents in working memory (WM) influences performance. A separate line of research has shown that stimulus strength shapes perceptual representations. There is little research on how stimulus strength during encoding shapes WM performance, and how effects of retrospective orienting might vary with changes in stimulus strength. We explore these questions in three experiments using a continuous-recall WM task. In Experiment 1 we show that benefits of cueing spatial attention retrospectively during WM maintenance (retrocueing) varies according to stimulus contrast during encoding. Retrocueing effects emerge for supraliminal but not sub-threshold stimuli. However, once stimuli are supraliminal, performance is no longer influenced by stimulus contrast. In Experiments 2 and 3 we used a mixture-model approach to examine how different sources of error in WM are affected by contrast and retrocueing. For high-contrast stimuli (Experiment 2), retrocues increased the precision of successfully remembered items. For low-contrast stimuli (Experiment 3), retrocues decreased the probability of mistaking a target with distracters. These results suggest that the processes by which retrospective attentional orienting shape WM performance are dependent on the quality of WM representations, which in turn depends on stimulus strength during encoding.

Capacity achieving nonbinary LDPC coded non-uniform shaping modulation for adaptive optical communications.

PubMed

Lin, Changyu; Zou, Ding; Liu, Tao; Djordjevic, Ivan B

2016-08-08

A mutual information inspired nonbinary coded modulation design with non-uniform shaping is proposed. Instead of traditional power of two signal constellation sizes, we design 5-QAM, 7-QAM and 9-QAM constellations, which can be used in adaptive optical networks. The non-uniform shaping and LDPC code rate are jointly considered in the design, which results in a better performance scheme for the same SNR values. The matched nonbinary (NB) LDPC code is used for this scheme, which further improves the coding gain and the overall performance. We analyze both coding performance and system SNR performance. We show that the proposed NB LDPC-coded 9-QAM has more than 2dB gain in symbol SNR compared to traditional LDPC-coded star-8-QAM. On the other hand, the proposed NB LDPC-coded 5-QAM and 7-QAM have even better performance than LDPC-coded QPSK.

Particle shape effect on heat transfer performance in an oscillating heat pipe.

PubMed

Ji, Yulong; Wilson, Corey; Chen, Hsiu-Hung; Ma, Hongbin

2011-04-05

The effect of alumina nanoparticles on the heat transfer performance of an oscillating heat pipe (OHP) was investigated experimentally. A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP. Four types of nanoparticles with shapes of platelet, blade, cylinder, and brick were studied, respectively. Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction. When the OHP was charged with EG and cylinder-like alumina nanoparticles, the OHP can achieve the best heat transfer performance among four types of particles investigated herein. In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP.

Particle shape effect on heat transfer performance in an oscillating heat pipe

PubMed Central

2011-01-01

The effect of alumina nanoparticles on the heat transfer performance of an oscillating heat pipe (OHP) was investigated experimentally. A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP. Four types of nanoparticles with shapes of platelet, blade, cylinder, and brick were studied, respectively. Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction. When the OHP was charged with EG and cylinder-like alumina nanoparticles, the OHP can achieve the best heat transfer performance among four types of particles investigated herein. In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP. PMID:21711830

Evaluation and comparison of an adaptive method technique for improved performance of linear Fresnel secondary designs

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

Hack, Madeline; Zhu, Guangdong; Wendelin, Timothy J.

As a line-focus concentrating solar power (CSP) technology, linear Fresnel collectors have the potential to become a low-cost solution for electricity production and a variety of thermal energy applications. However, this technology often suffers from relatively low performance. A secondary reflector is a key component used to improve optical performance of a linear Fresnel collector. The shape of a secondary reflector is particularly critical in determining solar power captured by the absorber tube(s), and thus, the collector's optical performance. However, to the authors' knowledge, no well-established process existed to derive the optimal secondary shape prior to the development of amore » new adaptive method to optimize the secondary reflector shape. The new adaptive method does not assume any pre-defined analytical form; rather, it constitutes an optimum shape through an adaptive process by maximizing the energy collection onto the absorber tube. In this paper, the adaptive method is compared with popular secondary-reflector designs with respect to a collector's optical performance under various scenarios. For the first time, a comprehensive, in-depth comparison was conducted on all popular secondary designs for CSP applications. In conclusion, it is shown that the adaptive design exhibits the best optical performance.« less

Evaluation and comparison of an adaptive method technique for improved performance of linear Fresnel secondary designs

DOE PAGES

Hack, Madeline; Zhu, Guangdong; Wendelin, Timothy J.

2017-09-13

As a line-focus concentrating solar power (CSP) technology, linear Fresnel collectors have the potential to become a low-cost solution for electricity production and a variety of thermal energy applications. However, this technology often suffers from relatively low performance. A secondary reflector is a key component used to improve optical performance of a linear Fresnel collector. The shape of a secondary reflector is particularly critical in determining solar power captured by the absorber tube(s), and thus, the collector's optical performance. However, to the authors' knowledge, no well-established process existed to derive the optimal secondary shape prior to the development of amore » new adaptive method to optimize the secondary reflector shape. The new adaptive method does not assume any pre-defined analytical form; rather, it constitutes an optimum shape through an adaptive process by maximizing the energy collection onto the absorber tube. In this paper, the adaptive method is compared with popular secondary-reflector designs with respect to a collector's optical performance under various scenarios. For the first time, a comprehensive, in-depth comparison was conducted on all popular secondary designs for CSP applications. In conclusion, it is shown that the adaptive design exhibits the best optical performance.« less