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1

TWIN SKEWED TRUSS RAILROAD BRIDGES NEAR BRIDGE STREET AT THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TWIN SKEWED TRUSS RAILROAD BRIDGES NEAR BRIDGE STREET AT THE WEST END OF THE PLANT. THIS VIEW PROBABLY LOOKING NORTHWEST. BRIDGES BUILT OVER ERIE CANAL (WHICH FLOWED RIGHT THROUGH THE MIDDLE OF THE PLANT) BY AMERICAN BRIDGE COMPANY IN 1902. SINCE THIS PHOTO WAS TAKEN, NEAR BRIDGE HAS BEEN DEMOLISHED; FAR BRIDGE IS STILL IN SERVICE. - Solvay Process Company, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

2

Evaluating the performance of skewed prestressed concrete bridge after strengthening  

NASA Astrophysics Data System (ADS)

The objectives of this paper are to explain the application of repairing and strengthening methods on the damaged members of the bridge structure, to analyze the static and dynamic structural response under static and dynamic loads after strengthening, and to evaluate the structural performance after application of strengthening method. The repairing and strengthening methods which are used in this study include treatment of the cracks, thickening the web of box girder along the bridge length and adding internal pre-stressing tendons in the thickening web, and construct reinforced concrete cross beams (diaphragms) between two box girders. The results of theoretical analysis of static and dynamic structural responses after strengthening show that the tensile stresses are decreased and become less than the allowable limit values in the codes. The values of vertical deflection are decreased after strengthening. The values of natural frequencies after strengthening are increased, indicating that the strengthening method is effective to reduce the vibration of the bridge structure. Therefore, the strengthening methods are effective to improve the bearing capacity and elastic working state of the bridge structure and to increase the service life of the bridge structure.

Naser, Ali Fadhil; Zonglin, Wang

2013-06-01

3

Buffeting response of long-span cable-supported bridges under skew winds. Part 1: theory  

NASA Astrophysics Data System (ADS)

A finite-element-based framework for buffeting analysis of long-span cable-supported bridges under skew winds is developed in the frequency domain utilizing the linear quasi-steady theory and the strip theory of aerodynamics in conjunction with the pseudo excitation method. A set of universal expressions for six components of buffeting forces is first derived in association with oblique cross-sections of bridge components, in which the buffeting forces are formed with respect to the wind coordinate system and then converted to those with respect to the structural coordinate system. Skew mean wind and three orthogonal components of velocity fluctuations can thus be easily handled without any further decomposition. The coherence between velocity fluctuations of wind turbulence at any two arbitrary spatial points is considered in the global wind coordinate system rather than in the global structural coordinate system. Aeroelastic stiffness and damping matrices due to self-excited forces are then taken into consideration in terms of the 18 flutter derivatives with respect to the oblique cross-sections. The pseudo-excitation method is finally employed to solve efficiently the fully coupled 3D buffeting problem of long-span cable-supported bridges under skew winds with the effects of multi-modes and spatial modes, inter-mode coupling and aerodynamic coupling, and the interaction among major bridge components being naturally included.

Zhu, L. D.; Xu, Y. L.

2005-03-01

4

Forces Exerted in the Wingwalls of Skewed Semi-Integral Bridges.  

National Technical Information Service (NTIS)

In the state of Ohio, semi-integral bridges have become more popular because these bridges eliminate high maintenance joints. The girders in a semi-integral bridge are encased in a diaphragm supported on elastometric pads that bear on the abutment. Moveme...

E. Steinberg S. Sargand

2001-01-01

5

Skew chromaticity  

SciTech Connect

The on-momentum description of linear coupling between horizontal and vertical betatron motion is extended to include off-momentum particles, introducing a vector quantity called the ``skew chromaticity``. This vector tends to be long in large superconducting storage rings, where it restricts the available working space in the tune plane, and modifies collective effect stability criteria. Skew chromaticity measurements at the Cornell Electron Storage Ring (CESR) and at the Fermilab Tevatron are reported, as well as tracking results from the Relativistic Heavy Ion Collider (RHIC). The observation of anomalous head-tail beam Iowa new the tune diagonal in the Tevatron are explained in terms of the extended theory, including modified criteria for headtail stability. These results are confirmed in head-tail simulations. Sources of skew chromaticity are investigated.

Peggs, S.; Dell, G.F.

1994-12-31

6

Bridges  

MedlinePLUS

... This type of bridge is also called a resin-bonded bridge or an acid-etched bridge. Bonded bridges usually ... are only as strong as the bonding material. Resin-bonded bridges tend not to stay cemented in place as ...

7

Bridges  

NSDL National Science Digital Library

Bridges come in a wide variety of sizes, shapes, and lengths and are found all over the world. It is important that bridges are strong so they are safe to cross. Design and build a your own model bridge. Test your bridge for strength using a force sensor that measures how hard you pull on your bridge. By observing a graph of the force, determine the amount of force needed to make your bridge collapse.

Consortium, The C.

2012-05-21

8

9. Skew Spanunderneath showing floor system for two tracks on ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. Skew Span-underneath showing floor system for two tracks on Main Bridge, from abutment end toward Rocker Bent. - Monongahela Connecting Railroad Company, Main Bridge, Spanning Monongahela River at mile post 3.1, Pittsburgh, Allegheny County, PA

9

Bridges  

NSDL National Science Digital Library

Bridges have been drawing plenty of attention lately, with numerous construction projects around the world and the controversy over the deteriorating bridge infrastructure in the US. They have been an essential part of transportation for hundreds of years, and it is the job of civil engineers to design the safest, most durable bridges possible.Bridge Basics (1) has a large list of different types of bridges with brief explanations. This is a good place for beginners to learn about various bridge designs and parts. The Web site of a nationwide engineering design contest (2) offers free West Point Bridge Designer software. This educational tool allows the user to create a custom virtual bridge model. Although this year's contest is over, another one is planned for next year. Rice University is the home of the Bridges Project (3), a comprehensive database of "all 74 1,000 ft. span bridges in the United States." For each of these, a short description and construction history are given, and some include photos and other interesting facts. The Gibraltar Bridge, a proposed nine mile bridge that connects Europe and Africa, was recently featured on the Discovery Channel's Engineering the Impossible (4). This Web site discusses its specifications, as well as the many challenges that must be overcome for it to be a reality. The Innovative Bridge Research and Construction Program (5) investigates new technologies that can be used in the "repair, rehabilitation, replacement and new construction of bridges" in the US. This is particularly important now, since a large portion of the countries bridges are badly in need of maintenance. A more specific area of research being conducted to protect bridge infrastructure involves the corrosion of steel reinforcements in concrete bridges (6). The material on this site provides an in-depth report on the findings of the Turner-Fairbank Highway Research Center. Technical reports and papers are published in the bimonthly Journal of Bridge Engineering (7). It covers almost any topic related to bridges, and is offered free online by the American Society of Civil Engineers. Fun activities for grade school students are given on this page (8). Separated into three levels of difficulty, the projects give students freedom to learn about and design any kind of bridge structure that interests them. A list of materials and criteria are given, but there are few explicit instructions, allowing for maximum creativity.

Leske, Cavin.

2002-01-01

10

12. Underside of Skew SpanHot Metal system on right, toward ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Underside of Skew Span-Hot Metal system on right, toward Rocker Bent. - Monongahela Connecting Railroad Company, Hot Metal Bridge, Spanning Monongahela River at mile post 3.1, Pittsburgh, Allegheny County, PA

11

8. Detail, skewed portal bracing at west portal, also showing ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Detail, skewed portal bracing at west portal, also showing boxed endposts, latticed upper transverse and diagonal sway bracing, laced vertical members, view to northeast, 210mm lens. - Southern Pacific Railroad Shasta Route, Bridge No. 301.85, Milepost 301.85, Pollard Flat, Shasta County, CA

12

Skew resisting hydrodynamic seal  

DOEpatents

A novel hydrodynamically lubricated compression type rotary seal that is suitable for lubricant retention and environmental exclusion. Particularly, the seal geometry ensures constraint of a hydrodynamic seal in a manner preventing skew-induced wear and provides adequate room within the seal gland to accommodate thermal expansion. The seal accommodates large as-manufactured variations in the coefficient of thermal expansion of the sealing material, provides a relatively stiff integral spring effect to minimize pressure-induced shuttling of the seal within the gland, and also maintains interfacial contact pressure within the dynamic sealing interface in an optimum range for efficient hydrodynamic lubrication and environment exclusion. The seal geometry also provides for complete support about the circumference of the seal to receive environmental pressure, as compared the interrupted character of seal support set forth in U.S. Pat. Nos. 5,873,576 and 6,036,192 and provides a hydrodynamic seal which is suitable for use with non-Newtonian lubricants.

Conroy, William T. (Pearland, TX); Dietle, Lannie L. (Sugar Land, TX); Gobeli, Jeffrey D. (Houston, TX); Kalsi, Manmohan S. (Houston, TX)

2001-01-01

13

Behavior of Ontario-Type Bridge Decks on Steel Girders. Final Report.  

National Technical Information Service (NTIS)

An experimental and analytical investigation was conducted regarding the behavior of reinforced concrete skew bridge decks with Ontario-type reinforcement. A series of parametric studies was also conducted to investigate the effect on bridge performance o...

K. H. Kim J. M. Dominguez R. E. Klingner N. H. Burns

1988-01-01

14

Elastoplastic large deflection analysis of end support diaphragms in skew steel box girders  

Microsoft Academic Search

Several studies on support diaphragms of steel box girders have been completed and some results of these studies have been incorporated into design rules. Almost all, however, assume support diaphragms placed orthogonally to the girder. Few studies have been done on skew bridge girder configurations, a number of which have recently been constructed.This paper reports on an elasto-plastic large deflection

Shigeru Shimizu

1995-01-01

15

Field Study of a Predeflected Steel-Concrete Composite Bridge.  

National Technical Information Service (NTIS)

Field tests were conducted on a skewed simple-span bridge to evaluate existing design standards for predeflected ('Preflex') steel-concrete composite beams. The test program consisted of midspan vertical displacement (deflection) measurements of these bea...

D. M. Cronk H. D. Rogers

1974-01-01

16

Skew chromaticity in large accelerators  

SciTech Connect

The 2-D ``skew chromaticity`` vector k is introduced when the standard on-momentum description of linear coupling is extended to include off-momentum particles. A lattice that is well decoupled on-momentum may be badly decoupled off-momentum, inside the natural momentum spread of the beam. There are two general areas of concern: (1) the free space in the tune plane is decreased; (2) collective phenomena may be destabilized. Two strong new criteria for head-tail stability in the presence of off-momentum coupling are derived, which are consistent with experimental and operational observations at the Tevatron, and with tracking data from RHIC.

Peggs, S.; Dell, G.F.

1995-05-01

17

Kinematic correction for roller skewing  

NASA Technical Reports Server (NTRS)

A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to produce changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.

Savage, M.; Loewenthal, S. H.

1980-01-01

18

Kinematic correction for roller skewing  

NASA Technical Reports Server (NTRS)

A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to product changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.

Savage, M.; Loewenthal, S. H.

1980-01-01

19

HOT METAL BRIDGE (NOTE: BUILDERS: JONES AND LAUGHLIN STEEL CA. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HOT METAL BRIDGE (NOTE: BUILDERS: JONES AND LAUGHLIN STEEL CA. 1890), SOUTH PORTAL. THREE PIN CONNECTED CAMELBACK TRUSS SPANS, ONE SKEWED THROUGH TRUSS SPAN ON NORTH SIDE TRUSS BRIDGE, EAST OF HOT METAL BRIDGE BUILT BY AMERICAN BRIDGE COMPANY CA. 1910. (RIVETED MULTI-SPAN TRUSS). - Jones & Laughlin Steel Corporation, Pittsburgh Works, Morgan Billet Mill Engine, 550 feet north of East Carson Street, opposite South Twenty-seventh Street, Pittsburgh, Allegheny County, PA

20

Roller skewing measurements in cylindrical roller bearings  

NASA Technical Reports Server (NTRS)

Measurements of roller skewing in a 118 mm bore roller bearing operating at shaft speeds to 12,000 rpm are reported. High speed motion pictures of a modified roller were taken through a derotation prism to record skewing as the roller moved through loaded and unloaded regions of the bearing. Subsequent frame by frame measurement of the photographic film provided information on roller skewing. Radial and tangential skew amplitudes of 0.4 to 0.5 degrees were observed with 0.5 degree misalignment.

Nypan, L. J.

1981-01-01

21

SKEW QUADRUPOLE FOCUSING LATTICES AND APPLICATIONS.  

SciTech Connect

In this paper we revisit using skew quadrupole fields in place of traditional normal upright quadrupole fields to make beam focusing structures. We illustrate by example skew lattice decoupling, dispersion suppression and chromatic correction using the neutrino factory Study-II muon storage ring design. Ongoing BNL investigation of flat coil magnet structures that allow building a very compact muon storage ring arc and other flat coil configurations that might bring significant magnet cost reduction to a VLHC motivate our study of skew focusing.

PARKER,B.

2001-06-18

22

Skewed Frequency Selective Surface Absorber  

NASA Astrophysics Data System (ADS)

In this paper, a skewed Frequency Selective Surface (FSS) absorber based on cross-dipole elements is presented. The proposed FSS design provides good frequency stability for oblique incidences. It provides better absorption rate for 5-GHz WLAN frequency band and allow other communication bands to pass through it. Also, the absorption in the stop-band reduces multipath fading of additional WLAN signals which occurred due to the placement of conducting/reflecting FSS. The FSS design consists of two layers; first layer consists of conducting cross-dipole and second layer consists of resistive cross-dipole placed in-front of the first layer. The periodicity of both elements is same. Asymmetric property is applied to FSS elements by taking a reference of central element. This technique leads to achieve a maximum stability in the stop-band. Simulated results demonstrated that the proposed FSS design has a stable frequency response for 5-GHz frequency band for both horizontal (TE) and vertical (TM) polarizations when the incident wave angle varied from 0 0 to 45 0.

Rafique, Umair; Khan, M. Arif; Afzal, M. Tausif; Malik, Fahad; Qasim, Shahzaib

2012-12-01

23

Bridge permeameter  

DOEpatents

A system for single-phase, steady-state permeability measurements of porous rock utilizes a fluid bridge arrangement analogous to a Wheatstone bridge. The arms of the bridge contain the sample and calibrated flow resistors.

Graf, Darin C. (Edgewood, NM); Warpinski, Norman R. (Albuquerque, NM)

1996-01-01

24

Skew estimation of document images using bagging.  

PubMed

This paper proposes a general-purpose method for estimating the skew angles of document images. Rather than to derive a skew angle merely from text lines, the proposed method exploits various types of visual cues of image skew available in local image regions. The visual cues are extracted by Radon transform and then outliers of them are iteratively rejected through a floating cascade. A bagging (bootstrap aggregating) estimator is finally employed to combine the estimations on the local image blocks. Our experimental results show significant improvements against the state-of-the-art methods, in terms of execution speed and estimation accuracy, as well as the robustness to short and sparse text lines, multiple different skews and the presence of nontextual objects of various types and quantities. PMID:20236898

Meng, Gaofeng; Pan, Chunhong; Zheng, Nanning; Sun, Chen

2010-07-01

25

Skew chicane based betatron eigenmode exchange module  

DOEpatents

A skewed chicane eigenmode exchange module (SCEEM) that combines in a single beamline segment the separate functionalities of a skew quad eigenmode exchange module and a magnetic chicane. This module allows the exchange of independent betatron eigenmodes, alters electron beam orbit geometry, and provides longitudinal parameter control with dispersion management in a single beamline segment with stable betatron behavior. It thus reduces the spatial requirements for multiple beam dynamic functions, reduces required component counts and thus reduces costs, and allows the use of more compact accelerator configurations than prior art design methods.

Douglas, David (Yorktown, VA)

2010-12-28

26

Designing Bridges  

NSDL National Science Digital Library

Students learn about the types of possible loads, how to calculate ultimate load combinations, and investigate the different sizes for the beams (girders) and columns (piers) of simple bridge design. Students learn the steps that engineers use to design bridges: understanding the problem, determining the potential bridge loads, calculating the highest possible load, and calculating the amount of material needed to resist the loads.

Integrated Teaching And Leaning Program And Laboratory

27

Spaghetti Bridge  

NSDL National Science Digital Library

In this engineering activity, learners investigate the differences between the strength of bridges made from flat and round building materials. They construct simple bridges out of linguine, which has a rectangular shape, and spaghetti, which has a circular shape. They then test and compare the weight capacity of the bridges.

Cosi

2009-01-01

28

Spaghetti Bridge  

NSDL National Science Digital Library

Civil engineers design structures such as buildings, dams, highways and bridges. Students explore the field of engineering by making a bridge using spaghetti as their primary building material. Then they test their bridges to see how much weight they can carry before breaking.

K-12 Outreach Office,

29

Bridge permeameter  

DOEpatents

A system is described for single-phase, steady-state permeability measurements of porous rock which utilizes a fluid bridge arrangement analogous to a Wheatstone bridge. The arms of the bridge contain the sample and calibrated flow resistors. 8 figs.

Graf, D.C.; Warpinski, N.R.

1996-08-13

30

Thermal postbuckling analysis of FGM skew plates  

Microsoft Academic Search

In this paper, the postbuckling behavior of functionally graded material (FGM) skew plates under thermal load is investigated based on the shear deformable finite element approach. The material is graded in the thickness direction according to a power-law distribution in terms of the volume fractions of the constituents. The Mori–Tanaka homogenization method is used to estimate the effective material properties

T. Prakash; M. K. Singha; M. Ganapathi

2008-01-01

31

Volume and skewness in international equity markets  

Microsoft Academic Search

We examine the relation between trading volume and skewness in 11 international stock markets using daily and monthly data from January 1980 to August 2004. We construct single equation and VAR models of the relation between the first three moments of market returns and trading volumes. Our results show hitherto unrecognised channels of influence, and support the investor heterogeneity approach

Elaine Hutson; Colm Kearney; Margaret Lynch

2008-01-01

32

Preference patterns for skewed gambles in rhesus monkeys.  

PubMed

While standard models of risky choice account for the first and second statistical moments of reward outcome distributions (mean and variance, respectively), they often ignore the third moment, skewness. Determining a decision-maker's attitude about skewness is useful because it can help constrain process models of the mental steps involved in risky choice. We measured three rhesus monkeys' preferences for gambles whose outcome distributions had almost identical means and variances but differed in skewness. We tested five distributions of skewness: strong negative, weak negative, normal, weak positive and strong positive. Monkeys preferred positively skewed gambles to negatively skewed ones and preferred strongly skewed and normal (i.e. unskewed) gambles to weakly skewed ones. This pattern of preferences cannot be explained solely by monotonic deformations of the utility curve or any other popular single account, but can be accounted for by multiple interacting factors. PMID:24335272

Strait, Caleb E; Hayden, Benjamin Y

2013-12-23

33

Digital Bridges  

NSDL National Science Digital Library

"The Digital Bridges Web site consists of a collection of thirty representative 19th century American bridge engineering monographs, manuals, and documents from the Lehigh University Libraries' Special Collections." The archive provides an interesting retrospective into the beginnings of major bridge projects; the material is complete with high-resolution photographs and text scanned from original books. In addition to historical literature, Digital Bridges also features brief accounts of notable people and companies that influenced bridge construction across the country. A glossary of terms commonly used in the documents is also provided.

2002-01-01

34

Document skew estimation: an approach based on wavelets  

Microsoft Academic Search

Document skew estimation refers to the process of finding the angle of inclination made by the document with respect to horizontal axis. The skew introduced during the scanning process like this is inevitable, even slightest degree of skew will always be there irrespective of how the document is fed to the scanner: either manually or automatically. Hence, deskewing of the

V. N. Manjunath Aradhya

2011-01-01

35

Fast Seamless Skew and Orientation Detection in Document Images  

Microsoft Academic Search

Reliable and generic methods for skew detection are a necessity for any large-scale digitization projects. As one of the first processing steps, skew detection and correction has a heavy influence on all further document analysis modules, such as geometric and logical layout analysis. This paper introduces a generic, scale-independent algorithm capable of accurately detecting the global skew angle of document

Iuliu Vasile Konya; Stefan Eickeler; Christoph Seibert

2010-01-01

36

A new estimate of skewness with mean-squared error smaller than that of the sample skewness  

Microsoft Academic Search

Recently, a new procedure for distribution fitting, based on matching of the first two moments, partial and complete, was introduced (Shore, 1995). When the sampling skewness of the fitted distribution is compared to the sample skewness, and both are regarded as estimates of the skewness of the underlying distribution, the mean-squared-error of the former is appreciably lower than that of

Shore Haim

1996-01-01

37

Skewness is the Name of the Game  

Microsoft Academic Search

Abstract Theoretical models,of risk taking attempt,to explain why,risk-averse individuals participate in unfair gambles. This paper evaluates the two explanations as to why,rational individuals would,accept gambles,with negative expected returns. It is found that it is skewness, not the mean or the variance of the prize distribution that attracts risk-averse gamblers. However, evidence shows that there seems to be an optimal trade-off

Y. H. Cheung

38

Spaghetti Bridge  

NSDL National Science Digital Library

Learners explore the field of civil engineering by making a bridge using spaghetti as their primary building material. Then they test their bridges to see how much weight they can carry before breaking. This activity allows learners to engage in the entire engineering process as they design, build, test, then discuss their bridges. Resource includes investigating questions to extend learning. Time estimated for activity can be split across multiple meetings.

Institute, Worcester P.

2005-01-01

39

Analysis of Parasite and Other Skewed Counts  

PubMed Central

Objective To review methods for the statistical analysis of parasite and other skewed count data. Methods Statistical methods for skewed count data are described and compared, with reference to those used over a ten year period of Tropical Medicine and International Health. Two parasitological datasets are used for illustration. Results Ninety papers were identified, 89 with descriptive and 60 with inferential analysis. A lack of clarity is noted in identifying measures of location, in particular the Williams and geometric mean. The different measures are compared, emphasizing the legitimacy of the arithmetic mean for skewed data. In the published papers, the t test and related methods were often used on untransformed data, which is likely to be invalid. Several approaches to inferential analysis are described, emphasizing 1) non-parametric methods, while noting that they are not simply comparisons of medians, and 2) generalized linear modelling, in particular with the negative binomial distribution. Additional methods, such as the bootstrap, with potential for greater use are described. Conclusions Clarity is recommended when describing transformations and measures of location. It is suggested that non-parametric methods and generalized linear models are likely to be sufficient for most analyses.

Alexander, Neal

2012-01-01

40

Straw Bridges  

NSDL National Science Digital Library

Working as engineering teams, students design and create model beam bridges using plastic drinking straws and tape as their construction materials. Their goal is to build the strongest bridge with a truss pattern of their own design, while meeting the design criteria and constraints. They experiment with different geometric shapes and determine how shapes affect the strength of materials. Let the competition begin!

Integrated Teaching And Learning Program

41

Active Bridging  

Microsoft Academic Search

Active networks accelerate network evolution by permitting the network infrastructure to be programmable, on a per-user, per-packet, or other basis. This programmability must be balanced against the safety and security needs inherent in shared resources.This paper describes the design, implementation, and performance of a new type of network element, an Active Bridge. The active bridge can be reprogrammed \\

D. Scott Alexander; Marianne Shaw; Scott M. Nettles; Jonathan M. Smith

1997-01-01

42

Safer Bridges  

NASA Technical Reports Server (NTRS)

Safer bridges are among a number of spinoff benefits from NASA procedures for testing 'cfracture toughness" of a structural part, meaning its ability to -siscracktsh at might cause failure. The New River Bridge in West Virginia, shown under construction, is the world's largest single span bridge. U.S. Steel fracture toughness requirements for such bridges include NASA-developed test procedures. Bridge materials and other metal structures may develop flaws during their service lifetimes. Such flaws can affect the structural integrity of the part. Thus, it is important to know the "fracture toughness" of a structural part, or its ability to resist cracks. NASA has long experience in developing fracture toughness tests for aerospace hardware. Since 1960, NASA-Lewis has worked closely with the American Society for Testing & Materials. Lewis and NASA-funded industrial contractors have made many important contributions to test procedures, now recommended by ASTM, for measuring fracture toughness.

1977-01-01

43

Analytical Seismic Fragility Curves for Typical Bridges in the Central and Southeastern United States  

Microsoft Academic Search

Seismic fragility curves for classes of highway bridges are essential for risk assessment of highway transportation networks exposed to seismic hazards. This study develops seismic fragility curves for nine classes of bridges (common three-span, zero-skew bridges with non-integral abutments) common to the central and southeastern United States. The methodology adopted uses 3-D analytical models and nonlinear time-history analyses. An important

Bryant G. Nielson; Reginald DesRoches

2007-01-01

44

Bayesian inference for finite mixtures of univariate and multivariate skew-normal and skew-t distributions.  

PubMed

Skew-normal and skew-t distributions have proved to be useful for capturing skewness and kurtosis in data directly without transformation. Recently, finite mixtures of such distributions have been considered as a more general tool for handling heterogeneous data involving asymmetric behaviors across subpopulations. We consider such mixture models for both univariate as well as multivariate data. This allows robust modeling of high-dimensional multimodal and asymmetric data generated by popular biotechnological platforms such as flow cytometry. We develop Bayesian inference based on data augmentation and Markov chain Monte Carlo (MCMC) sampling. In addition to the latent allocations, data augmentation is based on a stochastic representation of the skew-normal distribution in terms of a random-effects model with truncated normal random effects. For finite mixtures of skew normals, this leads to a Gibbs sampling scheme that draws from standard densities only. This MCMC scheme is extended to mixtures of skew-t distributions based on representing the skew-t distribution as a scale mixture of skew normals. As an important application of our new method, we demonstrate how it provides a new computational framework for automated analysis of high-dimensional flow cytometric data. Using multivariate skew-normal and skew-t mixture models, we could model non-Gaussian cell populations rigorously and directly without transformation or projection to lower dimensions. PMID:20110247

Frühwirth-Schnatter, Sylvia; Pyne, Saumyadipta

2010-04-01

45

Structure of attractors for skew product semiflows  

NASA Astrophysics Data System (ADS)

In this work we study the continuity and structural stability of the uniform attractor associated with non-autonomous perturbations of differential equations. By a careful study of the different definitions of attractor in the non-autonomous framework, we introduce the notion of lifted-invariance on the uniform attractor, which becomes compatible with the dynamics in the global attractor of the associated skew product semiflow, and allows us to describe the internal dynamics and the characterization of the uniform attractors. The associated pullback attractors and their structural stability under perturbations will play a crucial role.

Bortolan, M. C.; Carvalho, A. N.; Langa, J. A.

2014-07-01

46

Cable Stayed Timber Bridges.  

National Technical Information Service (NTIS)

A growing market segment open to timber bridges is pedestrian bridges crossing highways, railways and watercourses. These bridges are often calling for a long span and large vertical clearance under the bridge. Suspended and cable stayed bridges are attra...

A. Pousette

2001-01-01

47

Underside of span over Pickering Creek, showing highly skewed piers, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Underside of span over Pickering Creek, showing highly skewed piers, looking south. - Pennsylvania Railroad, Pickering Creek Trestle, Spanning Pickering Creek, south of Buckwalter Road, Pickering, Chester County, PA

48

Temperature-compensated clock skew adjustment.  

PubMed

This work analyzes several drift compensation mechanisms in wireless sensor networks (WSN). Temperature is an environmental factor that greatly affects oscillators shipped in every WSN mote. This behavior creates the need of improving drift compensation mechanisms in synchronization protocols. Using the Flooding Time Synchronization Protocol (FTSP), this work demonstrates that crystal oscillators are affected by temperature variations. Thus, the influence of temperature provokes a low performance of FTSP in changing conditions of temperature. This article proposes an innovative correction factor that minimizes the impact of temperature in the clock skew. By means of this factor, two new mechanisms are proposed in this paper: the Adjusted Temperature (AT) and the Advanced Adjusted Temperature (A2T). These mechanisms have been combined with FTSP to produce AT-FTSP and A2T-FTSP. Both have been tested in a network of TelosB motes running TinyOS. Results show that both AT-FTSP and A2T-FTSP improve the average synchronization errors compared to FTSP and other temperature-compensated protocols (Environment-Aware Clock Skew Estimation and Synchronization for WSN (EACS) and Temperature Compensated Time Synchronization (TCTS)). PMID:23966192

Castillo-Secilla, Jose María; Palomares, Jose Manuel; Olivares, Joaquín

2013-01-01

49

Bridging Anticoagulation  

MedlinePLUS

... Institution: NIH Library User Name Password Sign In Cardiology Patient Page Bridging Anticoagulation Is it Needed When ... Extract Free » Full Text Free PDF Free Classifications Cardiology Patient Page Services E-mail this article to ...

50

Spaghetti Bridge  

NSDL National Science Digital Library

Play with your food while learning about engineering! Build a spaghetti bridge, then test its strength by piling on the marshmallows, raw spaghetti, raw linguine and coins. Investigate the difference between the strength of bridges made from flat and round building materials (spaghetti is round, while linguine is flat). Learn by doing that circles are among the strongest shapes in nature, and that external and internal stress distributes itself evenly throughout a round structure.

Sciencenter

1999-01-01

51

Type-matching clock tree for zero skew clock gating  

Microsoft Academic Search

Clock skew minimization is always very important in the clock tree synthesis. Due to clock gating, the clock tree may include different types of logic gates, e.g., AND gates, OR gates, and buffer gates. If the logic gates at the same level are in different types, which have different timing behaviors, the control of clock skew becomes difficult. Based on

Chia-ming Chang; Shih-hsu Huang; Yuan-kai Ho; Jia-zong Lin; Hsin-po Wang; Yu-sheng Lu

2008-01-01

52

Learning a Novel Pattern through Balanced and Skewed Input  

ERIC Educational Resources Information Center

This study compared the effectiveness of balanced and skewed input at facilitating the acquisition of the transitive construction in Esperanto, characterized by the accusative suffix "-n" and variable word order (SVO, OVS). Thai university students (N = 98) listened to 24 sentences under skewed (one noun with high token frequency) or…

McDonough, Kim; Trofimovich, Pavel

2013-01-01

53

A Novel Low-Power Clock Skew Compensation Circuit  

Microsoft Academic Search

The clock is a periodic synchronization signal used as a time reference for data transfers in synchronous digital systems. However, the clock skew constrains the improvement of clock frequencies and affects the reliability of systems. One skew reduction technique is the use of clock deskew circuits. They can be classified into two methods: delay-locked loop (DLL) deskewing and synchronous mirror

Rong Ji; Liang Chen; Gang Luo; Xianjun Zeng; Junfeng Zhang; Yingjie Feng

2008-01-01

54

FLECHT low flooding rate skewed test series data report. [PWR  

Microsoft Academic Search

The FLECHT Low Flooding Rate Tests were conducted in an improved original FLECHT Test Facility to provide heat transfer coefficient and entrainment data at forced flooding rates of 1 in.\\/sec. and with electrically heated rod bundles which had cosine and top skewed axial power profiles. The top-skewed axial power profile test series has now been successfully completed and is here

E. R. Rosal; C. E. Conway; M. C. Krepinevich

1977-01-01

55

Accounting for Skewness in Ensemble Data Assimilation  

NASA Astrophysics Data System (ADS)

I will discuss a new framework for understanding how a non-normal probability density function (pdf) may affect a state estimate and how one might usefully exploit the non-normal properties of the pdf when constructing a state estimate. A Bayesian framework is constructed that leads naturally to an expansion of the expected forecast error in a polynomial series consisting of powers of the innovation vector. This polynomial expansion in the innovation reveals a new view of the geometric nature of the state estimation problem. Among other things a direct relationship is shown between the degree to which the state estimate varies with the innovation and the moments of the distribution. A practical data assimilation algorithm will also be presented that explicitly accounts for skewness in the prior distribution. The algorithm operates as a global-solve using a conjugate-gradient technique and Schur/Hadamard (element-wise) localization, and as a general rule is only a factor of four more expensive than the traditional ensemble Kalman filter. The central feature of this technique is the squaring of the innovation and the ensemble perturbations so as to create an extended state-space that accounts for the second, third and fourth moments of the prior distribution. This new technique is illustrated in a simple scalar system as well as in a Boussinesq model of O(10000) variables configured to simulate nonlinearly evolving Kelvin-Helmholtz waves in shear flow. It is shown that ensemble sizes of at least 100 members is needed to adequately resolve the third and fourth moments required for the algorithm. For ensembles of this size it is shown that this new technique is superior to a state-of-the-art Ensemble Kalman Filter in situations with significant skewness, otherwise the new algorithm reduces to the performance of the Ensemble Kalman Filter.

Hodyss, D.

2011-12-01

56

Basswood Bridges  

NSDL National Science Digital Library

The Elementary Engineering Design course for freshmen students at Purdue University Calumet consists of two components: one ME and one EE. Due to the two part structure and in order to expose the students to the faculty, it is also team taught. The course counts as two credits, with the format one hour lecture and three hours lab. The basswood bridge is the major project of the ME half and counts for one quarter of the total course grade. The object, as is usual with bridge projects, is to design, build and test a truss bridge having a high strength to weight ratio. The design process includes statics analysis in combination with the tensile and compressive properties of the basswood. The details of the project from initial design to final testing are provided.

Abramowitz, Harvey

2009-09-16

57

Linking Bridges  

NSDL National Science Digital Library

This blog post presents three puzzles which provide an opportunity for learners to use the strategy of trial and error and logical reasoning. The challenge is to connect all of the islands with bridges so that the number on the island corresponds to the number of bridges going to it or from it. This activity also provides the opportunity for students to be puzzle designers by including a blank grid page on which students can design their own versions of the puzzle to share with classmates.

Young, David

2014-01-28

58

Investigating the Investigative Task: Testing for Skewness--An Investigation of Different Test Statistics and Their Power to Detect Skewness  

ERIC Educational Resources Information Center

On the 2009 AP[c] Statistics Exam, students were asked to create a statistic to measure skewness in a distribution. This paper explores several of the most popular student responses and evaluates which statistic performs best when sampling from various skewed populations. (Contains 8 figures, 3 tables, and 4 footnotes.)

Tabor, Josh

2010-01-01

59

An 8-bit 100-MS/s digital-to-skew converter embedded switch with a 200-ps range for time-interleaved sampling  

NASA Astrophysics Data System (ADS)

A sampling switch with an embedded digital-to-skew converter (DSC) is presented. The proposed switch eliminates time-interleaved ADCs' skews by adjusting the boosted voltage. A similar bridged capacitors' charge sharing structure is used to minimize the area. The circuit is fabricated in a 0.18 ?m CMOS process and achieves sub-1 ps resolution and 200 ps timing range at a rate of 100 MS/s. The power consumption is 430 ?W at maximum. The measurement result also includes a 2-channel 14-bit 100 MS/s time-interleaved ADCs (TI-ADCs) with the proposed DSC switch's demonstration. This scheme is widely applicable for the clock skew and aperture error calibration demanded in TI-ADCs and SHA-less ADCs.

Xiaoshi, Zhu; Chixiao, Chen; Jialiang, Xu; Fan, Ye; Junyan, Ren

2013-03-01

60

Bridges, 2002.  

ERIC Educational Resources Information Center

This document is comprised of the one issue in volume 7 of "Bridges," a publication produced by the California Head Start-State Collaboration Office to detail the activities of the educational partnership and to provide relevant information to programs participating in the partnership. The Summer 2002 issue focuses on several topics of interest to…

Silver, Michael, Ed.; Zito, Michael, Ed.

2002-01-01

61

Paper Bridge  

NSDL National Science Digital Library

In this engineering activity, challenge learners to construct a paper bridge that can support 100 pennies. Learners discover how they can make a weak material like paper strong enough to support a load pennies by changing the shape of the paper (by rolling, crumpling or folding it).

Boston, Wgbh

2002-01-01

62

Bridges, 1999.  

ERIC Educational Resources Information Center

This volume contains articles about writing, best practice, portfolio assessment, and technology, as well as original poetry and book reviews. Articles in the volume are: "Teaching Writing: Making Connections" (Eric Schott); "Empowering Teachers: A Success Story" (Sandra L. Krivak); "Bridging the Gap between the Classroom and Employment" (Linda C.…

Wilcox, Bonita; Manear, John; Slifkin, Josh M.

63

Bridge Inspector's Training Manual.  

ERIC Educational Resources Information Center

A guide for the instruction of bridge inspectors is provided in this manual as well as instructions for conducting and reporting on a bridge inspection. The chapters outline the qualifications necessary to become a bridge inspector. The subject areas covered are: The Bridge Inspector, Bridge Structures, Bridge Inspection Reporting System,…

Federal Highway Administration (DOT), Washington, DC. Bureau of Public Roads.

64

The Belizean Bridge Activity.  

ERIC Educational Resources Information Center

Describes the famous swing bridge in Belize. Students build bridges from a variety of materials and answer the questions, What are different types of bridges?, How do bridges work?, How can you tell if a bridge design will be safe?, and What is the best way to build a bridge over a river while still allowing boat traffic? (SAH)

Murfin, Brian

2000-01-01

65

Digital Bridges: Bridges of the Nineteenth Century  

NSDL National Science Digital Library

The collection consists of thirty representative 19th-century American bridge engineering monographs, manuals, and documents from the Lehigh University Libraries' Special Collections. The source documents have been scanned, converted to text, and partially corrected to make all significant terms and personal and proper names retrievable through the site's search engine. Topics include specific bridges (the Brooklyn Bridge, the East River Bridge), bridge types (suspension bridges, wrought iron bridges), bridge components (cabling, foundations), bridge design, bridge disasters, and others. The collection is browseable by title and searchable by keyword. Printable versions of the documents are also available. A glossary is also provided with definitions of terms, short biographies of authors, and descriptions of some of the bridges

2002-01-01

66

Skew Disperson and Continuity of Local Time  

NASA Astrophysics Data System (ADS)

Results are provided that highlight the effect of interfacial discontinuities in the diffusion coefficient on the behavior of certain basic functionals of the diffusion, such as local times and occupation times, extending previous results in (Appuhamillage et al., Ann Appl Probab 21:183-214, 2011; Water Resour Res 46:W07511, 2009) on the behavior of first passage times. The main goal is to obtain a characterization of large scale parameters and behavior by an analysis at the fine scale of stochastic particle motions. In particular, considering particle concentration modeled by a diffusion equation with piecewise constant diffusion coefficient, it is shown that the continuity of a natural modification of local time is the individual (stochastic) particle scale equivalent to continuity of flux at the scale of the (macroscopic) particle concentrations. Consequences of this involve the determination of a skewness transmission probability in the presence of an interface, as well as corollaries concerning interfacial effects on occupation time of the associated stochastic particles.

Appuhamillage, Thilanka A.; Bokil, Vrushali A.; Thomann, Enrique A.; Waymire, Edward C.; Wood, Brian D.

2014-07-01

67

Bridge Building  

NSDL National Science Digital Library

This is a quick activity (on page 2 of the PDF) about how the arrangement of carbon atoms determines carbon's different properties. Learners will build bridges with Post-It notes that model two types of carbon molecules, graphite and carbon nanotubes, and test which structure of the same material can bear the weight of the most pennies. Also relates to linked video, DragonflyTV Nano: Hockey Sticks.

Twin Cities Public Television, Inc.

2008-01-01

68

Building Bridges  

NSDL National Science Digital Library

In this lesson, students build bridges from arithmetical to algebraic thinking by exploring problems that are not limited to single-solution responses. Values organized into tables and graphs are used to move toward symbolic representations. Problem situations at the middle school level involve linear, quadratic, and exponential models. The site is valuable not only for its problems for students but also for the teaching strategy illustrated here.

Day, Roger; Illustrations, Nctm

2000-01-01

69

Systems of Differential Equations with Skew-Symmetric, Orthogonal Matrices  

ERIC Educational Resources Information Center

The solution of a system of linear, inhomogeneous differential equations is discussed. The particular class considered is where the coefficient matrix is skew-symmetric and orthogonal, and where the forcing terms are sinusoidal. More general matrices are also considered.

Glaister, P.

2008-01-01

70

Experimental tool for generating ground truths for skewed page images  

NASA Astrophysics Data System (ADS)

We describe a new tool called GROTTO to generate ground truths for skewed page images, which can be used for performance evaluation of page segmentation algorithms. Some of these algorithms are claimed to be more or less insensitive to skew. However, this fact is usually only supported by a visual comparison of what one obtains and what one should obtain. As a result, the evaluation is both subjective, that is, prone to errors and tedious. Our tool allows users to quickly and easily produce many sufficiently accurate ground truths that can be employed in practice and therefore it facilitates automatic performance evaluation. The main idea is to utilize the ground truths available for upright images, that is, for those without skew, and the concept of the representative square in order to produce the ground truths for skewed images. The usefulness of our tool is demonstrated through a number of experiments described.

Okun, Oleg G.; Vesanen, Ari; Pietikaeinen, Matti

2000-12-01

71

Bicriterion seriation methods for skew-symmetric matrices.  

PubMed

The decomposition of an asymmetric proximity matrix into its symmetric and skew-symmetric components is a well-known principle in combinatorial data analysis. The seriation of the skew-symmetric component can emphasize information corresponding to the sign or absolute magnitude of the matrix elements, and the choice of objective criterion can have a profound impact on the ordering. In this research note, we propose a bicriterion approach for seriation of a skew-symmetric matrix incorporating both sign and magnitude information. Two numerical demonstrations reveal that the bicriterion procedure is an effective alternative to direct seriation of the skew-symmetric matrix, facilitating favourable trade-offs among sign and magnitude information. PMID:16293204

Brusco, Michael J; Stahl, Stephanie

2005-11-01

72

PRINCIPLE OF SKEW QUADRUPOLE MODULATION TO MEASURE BETATRON COUPLING.  

SciTech Connect

The measurement of the residual betatron coupling via skew quadrupole modulation is a new diagnostics technique that has been developed and tested at the Relativistic Heavy Ion Collider (RHIC) as a very promising method for the linear decoupling on the ramp. By modulating the strengths of different skew quadrupole families the two eigentunes are precisely measured with the phase lock loop system. The projections of the residual coupling coefficient onto the skew quadrupole coupling modulation directions are determined. The residual linear coupling could be corrected according to the measurement. An analytical solution for skew quadrupole modulation based on Hamiltonian perturbation approximation is given, and simulation code using smooth accelerator model is also developed. Some issues concerning the practical applications of this technique are discussed.

LUO.Y.PILAT,F.ROSER,T.ET AL.

2004-07-05

73

Extension of EMA to address regional skew and low outliers  

USGS Publications Warehouse

The recently developed expected moments algorithm [EMA] (Cohn et al. 1997) does as well as MLEs at estimating LP3 flood quantiles using systematic and historical information. Needed extensions include use of a regional skewness estimator and its precision to be consistent with Bulletin 17B and to make use of such hydrologic information. Another issue addressed by Bulletin 17B is the treatment of low outliers. A Monte Carlo study illustrates the performance of an extended EMA estimator compared to estimators that employ the complete data set with and without use of regional skew, conditional probability adjustment from Bulletin 17B, and an estimator that uses probability plot regression to compute substitute values for low outliers. Estimators that use a regional skew all do better than estimators that fail to use an informative regional skewness estimator. For LP3 data, the low outlier rejection procedure results in no loss of overall accuracy, and the differences between the MSEs of the estimators that used an informative regional skew were generally negligible in the skew range of real interest.

Griffis, V. W.; Stedinger, J. R.; Cohn, T. A.

2003-01-01

74

Flow in Rotating Serpentine Coolant Passages With Skewed Trip Strips  

NASA Technical Reports Server (NTRS)

Laser velocimetry was utilized to map the velocity field in serpentine turbine blade cooling passages with skewed trip strips. The measurements were obtained at Reynolds and Rotation numbers of 25,000 and 0.24 to assess the influence of trips, passage curvature and Coriolis force on the flow field. The interaction of the secondary flows induced by skewed trips with the passage rotation produces a swirling vortex and a corner recirculation zone. With trips skewed at +45 deg, the secondary flows remain unaltered as the cross-flow proceeds from the passage to the turn. However, the flow characteristics at these locations differ when trips are skewed at -45 deg. Changes in the flow structure are expected to augment heat transfer, in agreement with the heat transfer measurements of Johnson, et al. The present results show that trips are skewed at -45 deg in the outward flow passage and trips are skewed at +45 deg in the inward flow passage maximize heat transfer. Details of the present measurements were related to the heat transfer measurements of Johnson, et al. to relate fluid flow and heat transfer measurements.

Tse, David G.N.; Steuber, Gary

1996-01-01

75

Stock Return Characteristics, Skew Laws, and the Differential Pricing of Individual Equity Options  

Microsoft Academic Search

This article provides several new insights into the economic sources of skewness. First, we document the differential pricing of individual equity options versus the market index and relate it to variations in return skewness. Second, we show how risk aversion intro- duces skewness in the risk-neutral density. Third, we derive laws that decompose indi- vidual return skewness into a systematic

Gurdip S. Bakshi; Nikunj Kapadia; Dilip B. Madan

2001-01-01

76

Stock Return Characteristics, Skew Laws, and the Differential Pricing of Individual Equity Options  

Microsoft Academic Search

This article provides several new insights into the economic sources of skewness. First, we document the differential pricing of individual equity options versus the market index and relate it to variations in return skewness. Second, we show how risk aversion introduces skewness in the risk-neutral density. Third, we derive laws that decompose individual return skewness into a systematic component and

Gurdip Bakshi; Nikunj Kapadia; Dilip Madan

2003-01-01

77

Sample Skewness as a Statistical Measurement of Neuronal Tuning Sharpness  

PubMed Central

We propose using the statistical measurement of the sample skewness of the distribution of mean firing rates of a tuning curve to quantify sharpness of tuning. For some features, like binocular disparity, tuning curves are best described by relatively complex and sometimes diverse functions, making it difficult to quantify sharpness with a single function and parameter. Skewness provides a robust nonparametric measure of tuning curve sharpness that is invariant with respect to the mean and variance of the tuning curve and is straightforward to apply to a wide range of tuning, including simple orientation tuning curves and complex object tuning curves that often cannot even be described parametrically. Because skewness does not depend on a specific model or function of tuning, it is especially appealing to cases of sharpening where recurrent interactions among neurons produce sharper tuning curves that deviate in a complex manner from the feedforward function of tuning. Since tuning curves for all neurons are not typically well described by a single parametric function, this model independence additionally allows skewness to be applied to all recorded neurons, maximizing the statistical power of a set of data. We also compare skewness with other nonparametric measures of tuning curve sharpness and selectivity. Compared to these other nonparametric measures tested, skewness is best used for capturing the sharpness of multimodal tuning curves defined by narrow peaks (maximum) and broad valleys (minima). Finally, we provide a more formal definition of sharpness using a shape-based information gain measure and derive and show that skewness is correlated with this definition.

Samonds, Jason M.; Potetz, Brian R.; Lee, Tai Sing

2014-01-01

78

Building Big--Bridges  

NSDL National Science Digital Library

This web page describes different aspects of designing bridges. It relates the concept of bridge designing with the real life scenarios. It also includes some bridges around the world and gives some specifications of them.

2008-05-22

79

Building Big: Bridges  

NSDL National Science Digital Library

This web page describes different aspects of designing bridges. It relates the concept of bridge designing with the real life scenarios. It also includes some bridges around the world and gives some specifications of them.

Foundation, Wgbh E.

2006-07-11

80

OPERATIONAL MEASUREMENT OF COUPLING BY SKEW QUADRUPOLE MODULATION.  

SciTech Connect

The measurement and correction of the residual betatron coupling via skew quadrupole modulation is a new diagnostics technique that has been developed and tested at the Relativistic Heavy Ion Collider (RHIC) as a very promising method for the linear decoupling on the ramp. By modulating the strengths of the skew quadrupole families the two eigentune modulations are precisely measured with a high resolution phase lock loop system. The projections of the residual coupling coefficient onto the skew quadrupole coupling modulation direction are determined. The residual linear coupling could be corrected according the measurement. We report the results from the dedicated beam studies carried on at RHIC injection, store and on the ramp. A capability of measuring coupling on the ramp opens possibility of continuous coupling corrections during acceleration.

LUO.Y.CAMERON,P.LEE,R.ET AL.

2004-07-05

81

Build A Bridge  

NSDL National Science Digital Library

This wonderful site, provided by NOVA Online, brings to life the engineering challenges inherent to bridge-building. Designed for those who want the challenge, the site offers four bridging scenarios (with photos): "a 5,000-foot span across an ocean bay where huge ships come and go, ... a 700-foot span across a deep canyon gorge," and two others. A step-by-step tutorial teaches about four different bridge types (arch, beam, suspension, and cable-stayed), after which the user may select a bridge type for each scenario. The site is enhanced by links to other bridge resources, such as the famous bridge-building disaster of the century (Tacoma Narrows Bridge) and the Golden Gate Bridge site, which in turn, links users to other famous bridges including Japan's brand new Akashi Kaikyo Bridge, the longest bridge in the world.

1997-01-01

82

Power and Skew Aware Point Diffusion Clock Network  

NASA Astrophysics Data System (ADS)

This letter presents point diffusion clock network (PDCN) with local clock tree synthesis (CTS) scheme. The clock network is implemented with ten times wider metal line space than typical mesh networks for low power and utilized to nine times smaller area CTS execution for minimized clock skew amount. The measurement results show that skew amount of PDCN with local CTS is reduced to 36% and latency is shrunk to 45% of the amount in a 4.81mm2 CortexA-8 core with 65nm Samsung process.

Jung, Gunok; Kim, Chunghee; Chae, Kyoungkuk; Park, Giho; Park, Sung Bae

83

Bridge Needs, Design, and Performance,  

National Technical Information Service (NTIS)

The 14 papers in the report deal with the following areas: bridge strengthening needs in the United States; a bridge automated design and drafting system; bridge deck expansion joints; nonlinear analysis of highway bridges; prestressed waffle slab bridges...

K. F. Dunker F. W. Klaiber W. W. Sanders T. J. Tiberio J. C. Hayward

1987-01-01

84

On Optimal Backward Perturbation Analysis for the Linear System with Skew Circulant Coefficient Matrix  

PubMed Central

We first give the style spectral decomposition of a special skew circulant matrix C and then get the style decomposition of arbitrary skew circulant matrix by making use of the Kronecker products between the elements of first row in skew circulant and the special skew circulant C. Besides that, we obtain the singular value of skew circulant matrix as well. Finally, we deal with the optimal backward perturbation analysis for the linear system with skew circulant coefficient matrix on the base of its style spectral decomposition.

Jiang, Zhaolin; Shen, Nuo; Zhou, Jianwei

2013-01-01

85

Numerical and experimental analyses of an integral bridge  

NASA Astrophysics Data System (ADS)

In this paper, we present the analysis of a numerical and an experimental study of the Scotch Road integral abutment bridge located in Trenton, NJ, USA. Three-dimensional, nonlinear finite element (FE) model of the full bridge has been developed to study the effect of thermal loading on the bridge substructure. The bridge substructure was fully instrumented. Data analysis was performed to study the effect of several design parameters on axial stress in piles. An analysis of the pile-soil system was performed using the finite difference software LPILE. The maximum displacement of the bridge superstructure obtained from the FE model due to a maximum expected temperature change of ±42°C during the lifetime of the bridge was applied to the substructure model. The effect of bridge skew on the build-up of soil pressure behind the abutment was studied. A significant increase in the soil pressures and axial stresses behind the abutment at the obtuse side versus the acute was observed. The effect of the size of the galvanized steel sleeve on the induced axial stresses in piles was studied. We found that increasing the size of the steel sleeve increases their capacity to resist bending.

Khodair, Yasser; Hassiotis, Sophia

2013-12-01

86

Assistant detection of skewed data streams classification in cloud security  

Microsoft Academic Search

Data stream in the cloud is characterized by imbalanced distribution and concept drift. To solve the problem of classification of skewed and concept drift data stream in cloud security, we present an one-class classifier dynamic ensemble method which aims at separating virus data, reducing the amount of data analyzed in clouds, improving the efficiency of intrusion detection in cloud security

Qun Song; Jun Zhang; Qian Chi

2010-01-01

87

Design and Evaluation of a Highly Skewed Propeller.  

National Technical Information Service (NTIS)

The report discusses the design process and evaluation of a highly skewed propeller installed on the American Export Lines, Inc. 78a Class Roll-On/Roll-Off Cargo Vessel. The design process is discussed in detail including consideration of propeller excite...

1979-01-01

88

Making Skew-Resistant Fabrics For Composite Layups  

NASA Technical Reports Server (NTRS)

Fabrics used in curved composite-material structures prevented from skewing during composite layup by weaving them in modified process in which warp and fill yarns bonded together at their points of contact. (Bonding concept may prove similarly beneficial for braided and knitted fabrics.) In modified weaving process, adhesives prevent excessive shifting of warp and fill yarns with respect to each other.

Farley, Gary L.

1994-01-01

89

Skew reduction for synchronous OE-VLSI receiver applications  

Microsoft Academic Search

A dc photocurrent rejection technique for optically differential receivers is proposed to reduce the sensitivity of receiver latency to variations in average input photocurrent. This is particularly attractive in optoelectronic very large scale integration applications, where array-scale nonuniformity is significant. Using optically enabled ring oscillator experiments, we demonstrate that the technique is capable of removing between 50%-75% of the skew

Michael B. Venditti; Joshua D. Schwartz; David V. Plant

2004-01-01

90

Electronic skewing circuit monitors exact position of object underwater  

NASA Technical Reports Server (NTRS)

Linear Variable Differential Transformer /LVDT/ electronic skewing circuit guides a long cylindrical capsule underwater into a larger tube so that it does not contact the tube wall. This device detects movement of the capsule from a reference point and provides a continuous signal that is monitored on an oscilloscope.

Roller, R.; Yaroshuk, N.

1967-01-01

91

PERSPECTIVES Biodiversity loss, trophic skew and ecosystem functioning  

Microsoft Academic Search

Experiments testing biodiversity effects on ecosystem functioning have been criticized on the basis that their random-assembly designs do not reflect deterministic species loss in nature. Because previous studies, and their critics, have focused primarily on plants, however, it is underappreciated that the most consistent such determinism involves biased extinction of large consumers, skewing trophic structure and substantially changing conclusions about

J. Emmett Duffy

92

SKEW DETECTION AND COMPENSATION FOR INTERNET AUDIO APPLICA TIONS  

Microsoft Academic Search

Long lived audio streams, such as music broadcasts, and small differences in clock rates lead to buffer underflow or overflo w events in receiving applications that manifest themselves as au- dible interruptions. We present a low complexity algorithm for detecting clock skew in network audio applications that function with local clocks and in the absence of a synchronization mech- anism.

Orion Hodson; Colin Perkins; Vicky Hardman; Playout Delay

93

Analysis of skewed plates by a Trefftz collocation method  

Microsoft Academic Search

A boundary technique, based on the Trefftz method, is applied to the analysis of skewed thin plates. The formulation uses a superposition of the approximating functions of the displacements (and its derivatives) followed by the approximate satisfaction of the boundary conditions (bc) at suitably chosen boundary points. The least squares criterion is used to obtain the unknowns of the problem,

V. M. A. Leitão; C. M. T. Fernandes

94

Skew quadrupole in RHIC dipole magnets at high fields  

Microsoft Academic Search

In the RHIC are dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry

A. Jain; R. Gupta; P. Thompson; P. Wanderer

1996-01-01

95

Bridging the Gaps  

NSDL National Science Digital Library

Students are presented with a brief history of bridges as they learn about the three main bridge types: beam, arch and suspension. They are introduced to two natural forces â tension and compression â common to all bridges and structures. Throughout history, and today, bridges are important for connecting people to resources, places and other people. Students become more aware of the variety and value of bridges around us in our everyday lives.

Integrated Teaching and Learning Program, College of Engineering,

96

A Skew-Slit Collimator for Small Animal SPECT  

PubMed Central

The main objective of this paper is the development of a skew-slit collimator for small animal SPECT (single photon emission computed tomography) to replace the state-of-the-art multipinhole collimator. Methods A pinhole forms a cone-beam imaging geometry. If the collimator rotates around the object in a circular orbit, the projection measurements acquired by the cone-beam imaging geometry are incomplete and not enough for artifact-free image reconstruction. The severity of the artifact is proportional to the cone-angle of the pinhole in the direction of the axis of rotation. Multipinhole geometry can greatly reduce the data-insufficiency artifacts; however, image magnification is sacrificed. By transforming a pinhole into a pair of skewed slits, we are able to use a large cone-angle in the transaxial direction to increase image magnification, and a small cone-angle in the direction of axis of rotation in order to reduce the data-insufficiency artifacts. This is achieved by placing a vertical slit (that is, the slit is parallel to the axis of rotation) close to the object and placing a horizontal slit farther out. Similar to the multipinhole collimator, we also propose a multiple-skew-slit collimator that has one vertical slit and several horizontal slits. Results Computer simulations were performed to verify the working principle of the skew-slit collimator. A prototype multiple-skew-slit collimator was fabricated and phantom experiments were performed on a Philips IRIX system. The smallest channels (of 0.75 mm diameter) in the phantom are clearly separated in the reconstructed image. Conclusion This paper suggests a novel technology in small animal SPECT imaging to replace the multipinhole collimator, resulting in significantly reduced image artifacts and increased transaxial resolution. A physical multiple-skew-slit system was built and tested. Compared with the multipinhole system, the multiple-skew-slit system has a larger image magnification in the transaxial direction, and thus has better image resolution.

Zeng, Gengsheng L.

2009-01-01

97

Root waving and skewing: unexpectedly in micro-g.  

PubMed

Gravity has major effects on both the form and overall length of root growth. Numerous papers have documented these effects (over 300 publications in the last 5 years), the most well-studied being gravitropism, which is a growth re-orientation directed by gravity toward the earth's center. Less studied effects of gravity are undulations due to the regular periodic change in the direction root tips grow, called waving, and the slanted angle of growth roots exhibit when they are growing along a nearly-vertical surface, called skewing. Although diverse studies have led to the conclusion that a gravity stimulus is needed for plant roots to show waving and skewing, the novel results just published by Paul et al. (2012) reveal that this conclusion is not correct. In studies carried out in microgravity on the International Space Station, the authors used a new imaging system to collect digital photographs of plants every six hours during 15 days of spaceflight. The imaging system allowed them to observe how roots grew when their orientation was directed not by gravity but by overhead LED lights, which roots grew away from because they are negatively phototropic. Surprisingly, the authors observed both skewing and waving in spaceflight plants, thus demonstrating that both growth phenomena were gravity independent. Touch responses and differential auxin transport would be common features of root waving and skewing at 1-g and micro-g, and the novel results of Paul et al. will focus the attention of cell and molecular biologists more on these features as they try to decipher the signaling pathways that regulate root skewing and waving. PMID:23217095

Roux, Stanley J

2012-01-01

98

The Skew of Polar Crown X-ray Arcades  

NASA Astrophysics Data System (ADS)

A one-to-one relationship between the chirality of filament channels and the skew (relative orientation) of the overlying coronal arcades, as seen with the Yohkoh Soft X-ray Telescope (SXT) was found by Martin and McAllister [1997]. The basis of the relationship is a sample of over 30 mid-and low-latitude filaments during a 6 month period in early 1992. This relationship can be coupled with the predictions for the axial component of polar crown filaments based on the work of Leroy et al. [1983] to predict the skew of polar crown arcades in the recent cycle 22. Thus the axial component of the filament fields along the southern polar crown is predicted to point to the west and a similar component in the corona will lead to right skewed arcades. As has been pointed out in the past, this orientation is inconsistent with the action of photospheric differential rotation on an east-west arcade [Ballegooijen and Martens, 1990]. In this poster we report on the results of a recent survey of the SXT images over the whole declining phase of cycle 22 (Oct. 1991 to June 1995). These results are not in general agreement with those expected based on the past filament observations. They show highly left skewed polar arcades rather than the predicted right skew. The observations are, however, in general agreement with the effects of differential rotation and with recent numerical simulations of polar crown structures, which we will also briefly present. This posses an unexpected and challenging problem and we will discuss some possible ways of reconciling the different observational results. Leroy, Bommier, and Sahal-Brechot, The Magnetic Field in Prominences of the Polar Crown, Solar Physics, 83, 135-142, 1983. Martin and McAllister, The Chirality of X-ray Coronal Arcades Overlying Quiescent Filaments, Astrophys. Journ., submitted, 1997. Ballegooijen and Martens, Magnetic Fields in Quiescent Prominences, ApJ, 361, 283-289, 1990.

McAllister, A. H.; Mackay, D.; Hundhausen, A. J.; Priest, E.

1997-05-01

99

Arc voltage distribution skewness as an indicator of electrode gap during vacuum arc remelting  

DOEpatents

The electrode gap of a VAR is monitored by determining the skewness of a distribution of gap voltage measurements. A decrease in skewness indicates an increase in gap and may be used to control the gap.

Williamson, Rodney L. (Albuquerque, NM); Zanner, Frank J. (Sandia Park, NM); Grose, Stephen M. (Glenwood, WV)

1998-01-01

100

Arc voltage distribution skewness as an indicator of electrode gap during vacuum arc remelting  

DOEpatents

The electrode gap of a VAR is monitored by determining the skewness of a distribution of gap voltage measurements. A decrease in skewness indicates an increase in gap and may be used to control the gap. 4 figs.

Williamson, R.L.; Zanner, F.J.; Grose, S.M.

1998-01-13

101

The GC Skew Index: A Measure of Genomic Compositional Asymmetry and the Degree of Replicational Selection  

PubMed Central

Circular bacterial chromosomes have highly polarized nucleotide composition in the two replichores, and this genomic strand asymmetry can be visualized using GC skew graphs. Here we propose and discuss the GC skew index (GCSI) for the quantification of genomic compositional skew, which combines a normalized measure of fast Fourier transform to capture the shape of the skew graph and Euclidean distance between the two vertices in a cumulative skew graph to represent the degree of skew. We calculated GCSI for all available bacterial genomes, and GCSI correlated well with the visibility of GC skew. This novel index is useful for estimating confidence levels for the prediction of replication origin and terminus by methods based on GC skew and for measuring the strength of replicational selection in a genome.

Arakawa, Kazuharu; Tomita, Masaru

2007-01-01

102

The GC skew index: a measure of genomic compositional asymmetry and the degree of replicational selection.  

PubMed

Circular bacterial chromosomes have highly polarized nucleotide composition in the two replichores, and this genomic strand asymmetry can be visualized using GC skew graphs. Here we propose and discuss the GC skew index (GCSI) for the quantification of genomic compositional skew, which combines a normalized measure of fast Fourier transform to capture the shape of the skew graph and Euclidean distance between the two vertices in a cumulative skew graph to represent the degree of skew. We calculated GCSI for all available bacterial genomes, and GCSI correlated well with the visibility of GC skew. This novel index is useful for estimating confidence levels for the prediction of replication origin and terminus by methods based on GC skew and for measuring the strength of replicational selection in a genome. PMID:19461976

Arakawa, Kazuharu; Tomita, Masaru

2007-01-01

103

A Skew Distortion Correction Method for 2D Bar Code Images Based on Vanishing Points  

Microsoft Academic Search

The skew distortion is the crucial problem that influences the procession for the 2D bar code image recognition. However, as a result of the skew distortion, the vanishing points provide valuable information concerning the camera model used to capture the image. In this paper, a robust and fast algorithm for skew distortion correction in 2D bar code images based on

Xiao-Wei Xu; Zhi-Yan Wang; Yan-Qing Zhang; Ying-Hong Liang

2007-01-01

104

Critical comparison of viscoelastic damping and electrorheological fluid core damping in composite sandwich skew plates  

Microsoft Academic Search

Composite sandwich structures have extensive applications due to their high strength and structural efficiency. Skew fibre-reinforced composite laminates are used as important structural elements in modern structural design, particularly in the aerospace industry. Natural frequency of these skew laminates is of primary significance to structural designers. The present article studies the free vibration and damping characteristics of sandwich skew plates

G. Vishnu Narayana; N. Ganesan

2007-01-01

105

Skew modes in specialty fibers with step-index profile  

NASA Astrophysics Data System (ADS)

In step-index multimode-fibers, controlled excitation conditions are essential to achieve optimized transmission properties and control the output beam profile. Especially with lasers as a light-source, selective methods of mode excitation can be used easily. So far, fiber properties have been specified using meridional rays (modes), as proposed with the inverse far-field method. In addition to these meridional rays in step-index fibers, high-order skew rays can be selectively excited. Especially with excitation angles higher than the numerical aperture of the fiber, these skew rays can propagate with interesting properties. Based on these extreme test conditions, the core-cladding interface of large-core step-index fibers can be more efficiently controlled.

Klein, Karl-Friedrich; Gonschior, Cornell; Xia, Ruan; Hillrichs, Georg; Bloos, Martin; Poisel, Hans

2010-02-01

106

Skewed X Chromosome Inactivation and Trisomic Spontaneous Abortion: No Association  

PubMed Central

Several studies suggest that highly skewed X chromosome inactivation (HSXI) is associated with recurrent spontaneous abortion. We hypothesized that this association reflects an increased rate of trisomic conceptions due to anomalies on the X chromosome that lead both to HSXI and to a diminished oocyte pool. We compared the distribution of X chromosome inactivation (XCI) skewing percentages (range: 50%–100%) among women with spontaneous abortions in four karyotype groups—trisomy (n = 154), chromosomally normal male (n = 43), chromosomally normal female (n = 38), nontrisomic chromosomally abnormal (n = 61)—to the distribution for age-matched controls with chromosomally normal births (n = 388). In secondary analyses, we subdivided the nontrisomic chromosomally abnormal group, divided trisomies by chromosome, and classified women by reproductive history. Our data support neither an association of HSXI with all trisomies nor an association of HSXI with chromosomally normal male spontaneous abortions. We also find no association between HSXI and recurrent abortion (n = 45).

Warburton, Dorothy; Kline, Jennie; Kinney, Ann; Yu, Chih-yu; Levin, Bruce; Brown, Stephen

2009-01-01

107

Identification of spots in rotated and skewed microarray images  

NASA Astrophysics Data System (ADS)

DNA microarray image processing has vast potential in the measurement of mass gene expression. A common approach to processing microarrays consists of spot identification, spot segmentation, and information extraction. We are concerned with spot identification. We aim to tackle the problem of identifying spots in rotated and skewed arrays via an automated process. The method proposed is composed of three steps, namely, array orientation calculation based on the Hough transform, affine calculation and correction, and gridding. The method is able to correctly identify spots in a microarray that has been rotated or skewed at an angle between 0 and +/-30 deg and corrupted by various types of noise such as high-intensity streaks, Gaussian noise, and salt-and-pepper noise.

Le Brese, Christopher; Zou, Ju Jia

2009-12-01

108

Skew Divergence-Based Fuzzy Segmentation of Rock Samples  

NASA Astrophysics Data System (ADS)

Digital image segmentation is a process in which one assigns distinct labels to different objects in a digital image. The MOFS (Multi Object Fuzzy Segmentation) algorithm has been successfully applied to the segmentation of images from several modalities. However, the traditional MOFS algorithm fails when applied to images whose composing objects are characterized by textures whose patterns cannot be successfully described by simple statistics computed over a very restricted area. Here, we present an extension of the MOFS algorithm that achieves the segmentation of textures by employing adaptive affinity functions that use the Skew Divergence as a measure of distance between two distributions. These affinity functions are called adaptive because their associated area (neighborhood) changes according to the characteristics of the texture being processed. We performed experiments on mosaic images composed by combining rock sample images which show the effectiveness of the adaptive skew divergence based fuzzy affinity functions.

Carvalho, Bruno M.; Garduño, Edgar; Santos, Iraçú O.

2014-03-01

109

Skew and twist resistant hydrodynamic rotary shaft seal  

DOEpatents

A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which and cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland.

Dietle, Lannie (Sugar Land, TX); Kalsi, Manmohan Singh (Houston, TX)

1999-01-01

110

Skew and twist resistant hydrodynamic rotary shaft seal  

DOEpatents

A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland. 14 figs.

Dietle, L.; Kalsi, M.S.

1999-02-23

111

A Non-Gaussian Option Pricing Model with Skew  

Microsoft Academic Search

Closed form option pricing formulae explaining skew and smile are obtained within a parsimonious non-Gaussian framework. We extend the non-Gaussian option pricing model of L. Borland (Quantitative Finance, {\\\\bf 2}, 415-431, 2002) to include volatility-stock correlations consistent with the leverage effect. A generalized Black-Scholes partial differential equation for this model is obtained, together with closed-form approximate solutions for the fair

Lisa Borland; Jean-Philippe Bouchaud

2004-01-01

112

Incorporating Skew into RMS Surface Roughness Probability Distribution  

NASA Technical Reports Server (NTRS)

The standard treatment of RMS surface roughness data is the application of a Gaussian probability distribution. This handling of surface roughness ignores the skew present in the surface and overestimates the most probable RMS of the surface, the mode. Using experimental data we confirm the Gaussian distribution overestimates the mode and application of an asymmetric distribution provides a better fit. Implementing the proposed asymmetric distribution into the optical manufacturing process would reduce the polishing time required to meet surface roughness specifications.

Stahl, Mark T.; Stahl, H. Philip.

2013-01-01

113

A skew-symmetric cantilever accelerometer for automotive airbag applications  

Microsoft Academic Search

A piezoresistive cantilever-beam microaccelerometer has been designed, fabricated and tested with a hybrid airbag electronic control unit for automobile crash detection. A skew-symmetric accelerometer has been proposed and the associated fabrication process has been developed. A simultaneous etching process for beam-thickness control, fillet-rounding formation and corner compensation is discussed. The microfabricated device shows a flat response with a resonance frequency

Kyu Hyun Kim; Jong Soo Ko; Young-Ho Cho; Kwyro Lee; Byung Man Kwak

1995-01-01

114

Minority report in fraud detection: classification of skewed data  

Microsoft Academic Search

This paper proposes an innovative fraud detection method, built upon existing fraud detection research and Minority Report, to deal with the data mining problem of skewed data distributions. This method uses backpropagation (BP), together with naive Bayesian (NB) and C4.5 algorithms, on data partitions derived from minority oversampling with replacement. Its originality lies in the use of a single meta-classifier

Clifton Phua; Damminda Alahakoon; Vincent Lee

2004-01-01

115

Semiconductor bridge (SCB) detonator  

Microsoft Academic Search

The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to

Bickes Jr. Robert W; Mark C. Grubelich

1999-01-01

116

Semiconductor bridge (SCB) detonator  

Microsoft Academic Search

The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge (SCB) igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected

R. W. Jr. Bickes; M. C. Grubelich

1999-01-01

117

Kurtosis, skewness, and non-Gaussian cosmological density perturbations  

NASA Technical Reports Server (NTRS)

Cosmological topological defects as well as some nonstandard inflation models can give rise to non-Gaussian density perturbations. Skewness and kurtosis are the third and fourth moments that measure the deviation of a distribution from a Gaussian. Measurement of these moments for the cosmological density field and for the microwave background temperature anisotropy can provide a test of the Gaussian nature of the primordial fluctuation spectrum. In the case of the density field, the importance of measuring the kurtosis is stressed since it will be preserved through the weakly nonlinear gravitational evolution epoch. Current constraints on skewness and kurtosis of primeval perturbations are obtained from the observed density contrast on small scales and from recent COBE observations of temperature anisotropies on large scales. It is also shown how, in principle, future microwave anisotropy experiments might be able to reveal the initial skewness and kurtosis. It is shown that present data argue that if the initial spectrum is adiabatic, then it is probably Gaussian, but non-Gaussian isocurvature fluctuations are still allowed, and these are what topological defects provide.

Luo, Xiaochun; Schramm, David N.

1993-01-01

118

Validation of an Acoustic Impedance Prediction Model for Skewed Resonators  

NASA Technical Reports Server (NTRS)

An impedance prediction model was validated experimentally to determine the composite impedance of a series of high-aspect ratio slot resonators incorporating channel skew and sharp bends. Such structures are useful for packaging acoustic liners into constrained spaces for turbofan noise control applications. A formulation of the Zwikker-Kosten Transmission Line (ZKTL) model, incorporating the Richards correction for rectangular channels, is used to calculate the composite normalized impedance of a series of six multi-slot resonator arrays with constant channel length. Experimentally, acoustic data was acquired in the NASA Langley Normal Incidence Tube over the frequency range of 500 to 3500 Hz at 120 and 140 dB OASPL. Normalized impedance was reduced using the Two-Microphone Method for the various combinations of channel skew and sharp 90o and 180o bends. Results show that the presence of skew and/or sharp bends does not significantly alter the impedance of a slot resonator as compared to a straight resonator of the same total channel length. ZKTL predicts the impedance of such resonators very well over the frequency range of interest. The model can be used to design arrays of slot resonators that can be packaged into complex geometries heretofore unsuitable for effective acoustic treatment.

Howerton, Brian M.; Parrott, Tony L.

2009-01-01

119

Singularity analysis and steering control laws for adaptive-skew pyramid-type control moment gyros  

NASA Astrophysics Data System (ADS)

In contrast to past studies that have treated the skew angle as fixed in pyramid-type control moment gyro (CMG) systems, this paper treats the adaptive-skew pyramid-type CMG (ASCMG) system, in which the skew angle is one of the control variables for generating torques. The singular surfaces of the fixed-skew CMG are analyzed and visualized to illustrate how they depend on the skew angle, and the singular surfaces of the ASCMGs are also analyzed and visualized from a viewpoint of null motion for not only the gimbal angle but also the skew angle. The steering control laws are presented, and we numerically study their effectiveness for the reduction of settling time as compared to the fixed-skew pyramid-type CMGs.

Kojima, Hirohisa

2013-04-01

120

A method for generating skewed random numbers using two overlapping uniform distributions  

SciTech Connect

The objective of this work was to implement and evaluate a method for generating skewed random numbers using a combination of uniform random numbers. The method provides a simple and accurate way of generating skewed random numbers from the specified first three moments without an a priori specification of the probability density function. We describe the procedure for generating skewed random numbers from unifon-n random numbers, and show that it accurately produces random numbers with the desired first three moments over a range of skewness values. We also show that in the limit of zero skewness, the distribution of random numbers is an accurate approximation to the Gaussian probability density function. Future work win use this method to provide skewed random numbers for a Langevin equation model for diffusion in skewed turbulence.

Ermak, D.L. [Lawrence Livermore National Lab., CA (United States); Nasstrom, J.S. [EG and G Energy Measurements, Inc., Pleasanton, CA (United States)

1995-02-01

121

Low nasal bridge  

MedlinePLUS

A low nasal bridge is a flattening of the top part of the nose. ... Decreased growth (hypoplasia) of the nasal bridge can occur with infections or genetic diseases. A decrease in the height of the nasal bridge is best seen from a side ...

122

Science Shorts: Building Bridges  

NSDL National Science Digital Library

London Bridge is falling down, falling down...Can you finish the song? Although there are various stories that suggest the meaning of this famous nursery rhyme, the London Bridge, which spans the River Thames, did indeed "fall down" several times throughout history. This month's Science Shorts explores what makes bridges stay up. A corresponding activity is included.

Adams, Barbara

2006-07-01

123

Skew And Twist Resistant Hydrodynamic Rotary Shaft Seal  

DOEpatents

A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which and cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland. Compared to prior art, this invention provides a dramatic reduction of seal and shaft wear in abrasive environments and provides a significant increase in seal life.

Dietle, Lannie (Sugar Land, TX); Kalsi, Manmohan Singh (Houston, TX)

2000-03-14

124

Wigner-Yanase skew information as tests for quantum entanglement  

SciTech Connect

A Bell-type inequality is proposed in terms of Wigner-Yanase skew information, which is quadratic and involves only one local spin observable at each site. This inequality presents a hierarchic classification of all states of multipartite quantum systems from separable to fully entangled states, which is more powerful than the one presented by quadratic Bell inequalities from two-entangled to fully entangled states. In particular, it is proved that the inequality provides an exact test to distinguish entangled from nonentangled pure states of two qubits. Our inequality sheds considerable light on relationships between quantum entanglement and information theory.

Chen Zeqian [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, P.O. Box 71010, 30 West District, Xiao-Hong-Shan, Wuhan 430071 (China)

2005-05-15

125

Effect of Resonator Axis Skew on Normal Incidence Impedance  

NASA Technical Reports Server (NTRS)

High by-pass turbofan engines have fewer fan blades and lower rotation speeds than their predecessors. Consequently, the noise suppression at the low frequency end of the noise spectra has become an increasing concern. This has led to a renewed emphasis on improving noise suppression efficiency of passive, duct liner treatments at the lower frequencies. For a variety of reasons, passive liners are comprised of locally-reacting, resonant absorbers. One reason for this design choice is to satisfy operational and economic requirements. The simplest liner design consists of a single layer of honeycomb core sandwiched between a porous facesheet and an impervious backing plate. These resonant absorbing structures are integrated into the nacelle wall and are very ef- ficient over a limited bandwidth centered on their resonance frequency. Increased noise suppression bandwidth and greater suppression at lower frequencies is typically achieved for conventional liners by increasing the liner depth and incorporating thin porous septa into the honeycomb core. However, constraints on liner depth in modern high by-pass engine nacelles severely limit the suppression bandwidth extension to lower frequencies. Also, current honeycomb core liners may not be suitable for irregular geometric volumes heretofore not considered. It is of interest, therefore, to find ways to circumvent liner depth restrictions and resonator cavity shape constraints. One way to increase effective liner depth is to skew the honeycomb core axis relative to the porous facesheet surface. Other possibilities are to alter resonator cavity shape, e.g. high aspect ratio, narrow channels that possibly include right angle bends, 180. channel fold-backs, and splayed channel walls to conform to irregular geometric constraints. These possibilities constitute the practical motivation for expanding impedance modeling capability to include unconventional resonator orientations and shapes. The work reported in this paper is in the nature of a progress report and is limited to examining the implications of resonator axis skew on the composite normal incidence impedance of an array of resonator channels. Specifically, experimental results are compared with a modified impedance prediction model for highaspect- ratio, rectangular, resonator channels with varying amounts of skew relative to the incident particle velocity. It is shown that for resonator channel widths of 1 to 2 mm, aspect ratios of 25 to 50, and skew angles of zero to sixty degrees, the surface impedance of test models can be predicted with good accuracy. Predicted resistances and reactances are particularly well correlated through the first resonance and first anti-resonance for all six test models investigated. Beyond the first anti-resonance, the impedance prediction model loses the ability to predict details of resistance and reactance but still predicts the mean trends very well.

Parrott, Tony L.; Jones, Michael G.; Homeijer, Brian

2003-01-01

126

Boost bridge audio amplifier  

Microsoft Academic Search

The main difference in topology of a boost bridge amplifier and state-of-the-art class-D amplifier is in the connection of a loudspeaker between a power supply and a switching bridge. The boost bridge amplifier provides four times higher peak power at the loudspeaker than the power, which can be achieved by a class-D amplifier from the same power supply. Total harmonic

Milan Prokin

2001-01-01

127

Built-in clock skew system for on-line debug and repair  

Microsoft Academic Search

We present a low-cost on-line system for clock skew management in integrated circuits. Our Built-In Clock Skew System (BICSS) uses a centralized approach to identify, quantify and correct skew using a two-step method. The technique assesses the time-of-flight between the central debug circuitry and each region, or tap under test to account for the measurement error due to differences in

Atanu Chattopadhyay; Zeljko Zilic

2008-01-01

128

Built-in Clock Skew System for On-line Debug and Repair  

Microsoft Academic Search

We present a low-cost on-line system for clock skew management in integrated circuits. Our built-in clock skew system (BICSS) uses a centralized approach to identify, quantify and correct skew using a two-step method. The technique assesses the time-off-light between the central debug circuitry and each region, or tap under test to account for the measurement error due to differences in

Atanu Chattopadhyay; Zeljko Zilic

2008-01-01

129

Semiconductor bridge (SCB) detonator  

SciTech Connect

The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge (SCB) igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length. 3 figs.

Bickes, R.W. Jr.; Grubelich, M.C.

1999-01-19

130

Skewness and shock formation in laboratory-scale supersonic jet data.  

PubMed

Spatial properties of noise statistics near unheated, laboratory-scale supersonic jets yield insights into source characteristics and near-field shock formation. Primary findings are (1) waveforms with positive pressure skewness radiate from the source with a directivity upstream of maximum overall level and (2) skewness of the time derivative of the pressure waveforms increases significantly with range, indicating formation of shocks during propagation. These results corroborate findings of a previous study involving full-scale engine data. Further, a comparison of ideally and over-expanded laboratory data show that while derivative skewness maps are similar, waveform skewness maps are substantially different for the two cases. PMID:23742445

Gee, Kent L; Neilsen, Tracianne B; Atchley, Anthony A

2013-06-01

131

Problematic standard errors and confidence intervals for skewness and kurtosis.  

PubMed

Many statistics packages print skewness and kurtosis statistics with estimates of their standard errors. The function most often used for the standard errors (e.g., in SPSS) assumes that the data are drawn from a normal distribution, an unlikely situation. Some textbooks suggest that if the statistic is more than about 2 standard errors from the hypothesized value (i.e., an approximate value for the critical value from the t distribution for moderate or large sample sizes when ? = 5%), the hypothesized value can be rejected. This is an inappropriate practice unless the standard error estimate is accurate and the sampling distribution is approximately normal. We show distributions where the traditional standard errors provided by the function underestimate the actual values, often being 5 times too small, and distributions where the function overestimates the true values. Bootstrap standard errors and confidence intervals are more accurate than the traditional approach, although still imperfect. The reasons for this are discussed. We recommend that if you are using skewness and kurtosis statistics based on the 3rd and 4th moments, bootstrapping should be used to calculate standard errors and confidence intervals, rather than using the traditional standard. Software in the freeware R for this article provides these estimates. PMID:21298573

Wright, Daniel B; Herrington, Joshua A

2011-03-01

132

Skewed sex ratios in India: "physician, heal thyself".  

PubMed

Sex selection, a gender discrimination of the worst kind, is highly prevalent across all strata of Indian society. Physicians have a crucial role in this practice and implementation of the Indian Government's Pre-Natal Diagnostic Techniques Act in 1996 to prevent the misuse of ultrasound techniques for the purpose of prenatal sex determination. Little is known about family preferences, let alone preferences among families of physicians. We investigated the sex ratios in 946 nuclear families with 1,624 children, for which either one or both parents were physicians. The overall child sex ratio was more skewed than the national average of 914. The conditional sex ratios decreased with increasing number of previous female births, and a previous birth of a daughter in the family was associated with a 38 % reduced likelihood of a subsequent female birth. The heavily skewed sex ratios in the families of physicians are indicative of a deeply rooted social malady that could pose a critical challenge in correcting the sex ratios in India. PMID:23322380

Patel, Archana B; Badhoniya, Neetu; Mamtani, Manju; Kulkarni, Hemant

2013-06-01

133

A skewed homogeneous lagrangian particle model for convective conditions  

NASA Astrophysics Data System (ADS)

Numerical solution of the Langevin equation for convective conditions usually requires quite small time steps in order to resolve properly the smaller-scale turbulence near the boundaries. This time step restriction can be eased significantly if it is assumed that the turbulence is uniform over the whole depth of the mixed layer. In this paper, we investigate the effect of this homogeneous turbulence assumption on ground-level concentration (glc) by comparing results with (a) the Willis and Deardorff laboratory experiments on dispersion in fully convective conditions and (b) the predictions of a model employing a more realistic inhomogeneous parameterization for the turbulence. As far as the ability to predict the magnitude and location of the near-source maximum glc, and the ability to maintain a well-mixed profile further downwind are concerned, we conclude that the assumption of homogeneous turbulence is quite adequate. We also compare Gaussian and skewed distributions for homogeneous turbulence and show that realistic results in convective conditions can only be obtained with the skewed distribution.

Hurley, Peter; Physick, William

134

Hölder properties of perturbed skew products and Fubini regained  

NASA Astrophysics Data System (ADS)

In 2006, Gorodetski proved that central fibres of perturbed skew products are Hölder continuous with respect to the base point. In this paper, we give an explicit estimate of this Hölder exponent. Moreover, we extend Gorodetski's result from the case when the fibre maps are close to the identity to a much wider class of maps that satisfy the so-called modified dominated splitting condition. In many cases (for example, in the case of skew products over the solenoid or over linear Anosov diffeomorphisms of the torus), the Hölder exponent is close to 1. This allows one to overcome the so-called Fubini nightmare, in some sense. Namely, we prove that the union of central fibres that are strongly atypical from the point of view of ergodic theory, has Lebesgue measure zero despite the lack of absolute continuity of the holonomy map for the central foliation. This result is based on a new kind of ergodic theorem, which we call special. To prove our main result, we revisit the theory of Hirsch, Pugh and Shub, and estimate the contraction constant of the graph transform map.

Ilyashenko, Yu; Negut, A.

2012-08-01

135

Crossover ensembles of random matrices and skew-orthogonal polynomials  

SciTech Connect

Highlights: > We study crossover ensembles of Jacobi family of random matrices. > We consider correlations for orthogonal-unitary and symplectic-unitary crossovers. > We use the method of skew-orthogonal polynomials and quaternion determinants. > We prove universality of spectral correlations in crossover ensembles. > We discuss applications to quantum conductance and communication theory problems. - Abstract: In a recent paper (S. Kumar, A. Pandey, Phys. Rev. E, 79, 2009, p. 026211) we considered Jacobi family (including Laguerre and Gaussian cases) of random matrix ensembles and reported exact solutions of crossover problems involving time-reversal symmetry breaking. In the present paper we give details of the work. We start with Dyson's Brownian motion description of random matrix ensembles and obtain universal hierarchic relations among the unfolded correlation functions. For arbitrary dimensions we derive the joint probability density (jpd) of eigenvalues for all transitions leading to unitary ensembles as equilibrium ensembles. We focus on the orthogonal-unitary and symplectic-unitary crossovers and give generic expressions for jpd of eigenvalues, two-point kernels and n-level correlation functions. This involves generalization of the theory of skew-orthogonal polynomials to crossover ensembles. We also consider crossovers in the circular ensembles to show the generality of our method. In the large dimensionality limit, correlations in spectra with arbitrary initial density are shown to be universal when expressed in terms of a rescaled symmetry breaking parameter. Applications of our crossover results to communication theory and quantum conductance problems are also briefly discussed.

Kumar, Santosh, E-mail: skumar.physics@gmail.com [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India); Pandey, Akhilesh, E-mail: ap0700@mail.jnu.ac.in [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)

2011-08-15

136

GOETHALS BRIDGE FROM NORTH SIDE OVER ARTHUR KILL. RAILROAD BRIDGE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GOETHALS BRIDGE FROM NORTH SIDE OVER ARTHUR KILL. RAILROAD BRIDGE IN FOREGROUND - Goethals Bridge, Spanning Arthur Kill from New Jersey to Staten Island, Staten Island (subdivision), Richmond County, NY

137

DISTANT ELEVATION, NOTE CREEK BRIDGE FOREGROUND, COVERED BRIDGE OVER DIFFERENT ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DISTANT ELEVATION, NOTE CREEK BRIDGE FOREGROUND, COVERED BRIDGE OVER DIFFERENT STREAM IN THE BACKGROUND, NORTHEAST PORTAL - Larwood Bridge, Spanning Crabtree Creek, Fish Hatchery Road (CR 648), Lacomb, Linn County, OR

138

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM BELOW, SHOWING VALVE TOWER TO RIGHT. VIEW FACING NORTH - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream East Range, Wahiawa, Honolulu County, HI

139

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM ENTRY. VIEW FACING NORTHWEST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream East Range, Wahiawa, Honolulu County, HI

140

SULPHITE BRIDGE FROM DOWNSTREAM, BEARING NORTHEAST 25 DEGREES. THE BRIDGE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

SULPHITE BRIDGE FROM DOWNSTREAM, BEARING NORTHEAST 25 DEGREES. THE BRIDGE ONCE HAD VERTICAL BOARD SIDING BUT VANDALS BURNED IT OFF IN 1981 - Sulphite Railroad Bridge, Former Boston & Maine Railroad (originally Tilton & Franklin Railroad) spanning Winnipesautee River, Franklin, Merrimack County, NH

141

1. VIEW OF SWING BRIDGE FROM KEDZIE AVENUE BRIDGE, LOOKING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VIEW OF SWING BRIDGE FROM KEDZIE AVENUE BRIDGE, LOOKING EAST. - Chicago, Madison & Northern Railroad, Sanitary & Ship Canal Bridge, Spanning Sanitary & Ship Canal, east of Kedzie Avenue, Chicago, Cook County, IL

142

Plans: Poop Deck, Boat Deck, Housetop, Bridge Deck, Upper Bridge ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Plans: Poop Deck, Boat Deck, Housetop, Bridge Deck, Upper Bridge Deck, Navigating Bridge, Forecastle Deck, Upper Deck, Second Deck and Hold - Saugatuck, James River Reserve Fleet, Newport News, Newport News, VA

143

Sulphite Railroad Bridge1896, Title Sheet Sulphite Railroad Bridge, Former ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Sulphite Railroad Bridge-1896, Title Sheet - Sulphite Railroad Bridge, Former Boston & Maine Railroad (originally Tilton & Franklin Railroad) spanning Winnipesautee River, Franklin, Merrimack County, NH

144

Modelling a Suspension Bridge.  

ERIC Educational Resources Information Center

The quadratic function can be modeled in real life by a suspension bridge that supports a uniform weight. This activity uses concrete models and computer generated graphs to discover the mathematical model of the shape of the main cable of a suspension bridge. (MDH)

Rawlins, Phil

1991-01-01

145

Bridges and Culverts.  

National Technical Information Service (NTIS)

The 16 papers in this report deal with the following areas: field testing of the Fremont Bridge; seismic design of curved box girders; test to failure of the Hannacroix Creek Bridge; load factor design applied to truss members in design of Greater New Orl...

M. J. Koob J. M. Hanson C. P. Heins I. C. Lin D. B. Beal

1983-01-01

146

Bridge Program Planning Guide  

NSDL National Science Digital Library

This report discusses bridge training programs which are designed to "prepare individuals without the requisite basic skills for postsecondary training leading to career-path employment and further learning in a specific industry or occupational sector." This guide is intended to help those representing community colleges, community organizations, and others plan the development of bridge training programs.

Jenkins, Davis

2012-01-26

147

Support Column of Bridge  

USGS Multimedia Gallery

Support column of bridge across Struve Slough, Highway 1. Enlargement of hole where support enters the ground is an effect of lateral shaking, which caused the concrete to break up where the column joined the bridge and was instrumental in the roadbed collapse....

2009-01-26

148

Bridge and Hydrology Research, 1991.  

National Technical Information Service (NTIS)

Partial Contents: Aesthetically Pleasing Steel Pipe Bridge Rail; Oak A-Frame Timber Bridges Meeting the Modern Deflection Requirement; Behavior and Design of Moment-Reducing Details for Bridge Column-Foundation Connections; Climbing: A Unique and Effectiv...

1991-01-01

149

Constant Current Strain Gauge Bridge.  

National Technical Information Service (NTIS)

All the early electrical strain gauge bridge circuits employed constant voltage sources for bridge excitation. The techniques developed for the classical direct-current and alternating-current component-measuring bridges were transferred to the strain gau...

E. S. Moody

1984-01-01

150

Building Our Bridge to Fun!  

NSDL National Science Digital Library

Students identify different bridge designs and construction materials used in modern day engineering. They work in construction teams to create paper bridges and spaghetti bridges based on existing bridge designs. Students progressively realize the importance of the structural elements in each bridge. They also measure vertical displacements under the center of the spaghetti bridge span when a load is applied. Vertical deflection is measured using a LEGO® MINDSTORMS® NXT intelligent brick and ultrasonic sensor. As they work, students experience tension and compression forces acting on structural elements of the two bridge prototypes. In conclusion, students discuss the material properties of paper and spaghetti and compare bridge designs with performance outcomes.

Applying Mechatronics to Promote Science (AMPS) GK-12 Program,

151

Guaranteeing Convergence of Iterative Skewed Voting Algorithms for Image Segmentation  

PubMed Central

In this paper we provide rigorous proof for the convergence of an iterative voting-based image segmentation algorithm called Active Masks. Active Masks (AM) was proposed to solve the challenging task of delineating punctate patterns of cells from fluorescence microscope images. Each iteration of AM consists of a linear convolution composed with a nonlinear thresholding; what makes this process special in our case is the presence of additive terms whose role is to “skew” the voting when prior information is available. In real-world implementation, the AM algorithm always converges to a fixed point. We study the behavior of AM rigorously and present a proof of this convergence. The key idea is to formulate AM as a generalized (parallel) majority cellular automaton, adapting proof techniques from discrete dynamical systems.

Balcan, Doru C.; Srinivasa, Gowri; Fickus, Matthew; Kovacevic, Jelena

2012-01-01

152

Cracked shells under skew-symmetric loading. [Reissner theory  

NASA Technical Reports Server (NTRS)

The general problem of a shell containing a through crack in one of the principal planes of curvature and under general skew-symmetric loading is considered. By employing a Reissner type shell theory which takes into account the effect of transverse shear strains, all boundary conditions on the crack surfaces are satisfied separately. Consequently, unlike those obtained from the classical shell theory, the angular distributions of the stress components around the crack tips are shown to be identical to the distributions obtained from the plane and anti-plane elasticity solutions. Results are given for axially and circumferentially cracked cylindrical shells, spherical shells, and toroidal shells under uniform in-plane shearing, out of plane shearing, and torsion. The problem is formulated for specially orthostropic materials, therefore, the effect of orthotropy on the results is also studied.

Delale, F.

1981-01-01

153

Restoring the skew quadrupole moment in the Tevatron dipoles  

SciTech Connect

In early 2003 it was realized that mechanical changes in the Tevatron dipoles had led to a deterioration of the magnetic field quality that was hindering operation of the accelerator. After extensive study, a remediation program was started in late 2003 that will continue through 2005. The mechanical and magnetic effects are discussed. The readjustment process and experience are reported, along with other observations on aging magnets. In January 2003 two lines of inquiry converged, leading to the recognition that the severe betatron coupling that was hindering operation of the Tevatron could be explained by a systematic shift on the skew quadrupole field in the dipole magnets of the same size expected from observed mechanical movement of the coils inside the magnet yokes [1]. This paper reports on subsequent magnet studies that were conducted in parallel with additional beam studies and accelerator modeling [2] exploring the feasibility of the eventual remediation effort [3].

Harding, D.J.; Bauer, P.C.; Blowers, J.N.; DiMarco, J.; Glass, H.D.; Hanft, R.W.; Carson, J.A.; Robotham, W.F.; Tartaglia, M.A.; Tompkins, J.C.; Velev, G.; /Fermilab

2005-05-01

154

Automatic identification and skew estimation of text lines in real scene images  

Microsoft Academic Search

A method for the automatic localization of text em- bedded in complex images is proposed. It permits to detect the spatial position and the skew of the text lines which are present in the scene and to return a bi- nary representation of each text line. Strenghts of the algorithm are independece of text skew and of pres- ence of

Stefano Messelodi; Carla Maria Modena

1999-01-01

155

An Improved Clock-skew Measurement Technique for Revealing Hidden Services  

Microsoft Academic Search

The Tor anonymisation network allows services, such as web servers, to be operated under a pseudonym. In pre- vious work Murdoch described a novel attack to reveal such hidden services by correlating clock skew changes with times of increased load, and hence temperature. Clock skew measurement suffers from two main sources of noise: network jitter and timestamp quantisation er- ror.

Sebastian Zander; Steven J. Murdoch

2008-01-01

156

On the helical tooth flank synthesis of skew-axes gear pairs  

Microsoft Academic Search

An approach to the kinematic method of skew-axes gear synthesis is presented in the work. The object of the investigation is an illustration of the pitch point mathematical model for synthesis of the spatial gear pair helical flanks. This mathematical model has been applied in the designing of different kinds of skew-axes gear pairs. Algorithms and CAD systems for Spiroid

Valentin Abadjiev

2001-01-01

157

Transactional skew and assured fitness return models fail to predict patterns of cooperation in wasps.  

PubMed

Cooperative breeders often exhibit reproductive skew, where dominant individuals reproduce more than subordinates. Two approaches derived from Hamilton's inclusive fitness model predict when subordinate behavior is favored over living solitarily. The assured fitness return (AFR) model predicts that subordinates help when they are highly likely to gain immediate indirect fitness. Transactional skew models predict dominants and subordinates "agree" on a level of reproductive skew that induces subordinates to join groups. We show the AFR model to be a special case of transactional skew models that assumes no direct reproduction by subordinates. We use data from 11 populations of four wasp species (Polistes, Liostenogaster) as a test of whether transactional frameworks suffice to predict when subordinate behavior should be observed in general and the specific level of skew observed in cooperative groups. The general prediction is supported; in 10 of 11 cases, transactional models correctly predict presence or absence of cooperation. In contrast, the specific prediction is not consistent with the data. Where cooperation occurs, the model accurately predicts highly biased reproductive skew between full sisters. However, the model also predicts that distantly related or unrelated females should cooperate with low skew. This prediction fails: cooperation with high skew is the observed norm. Neither the generalized transactional model nor the special-case AFR model can explain this significant feature of wasp sociobiology. Alternative, nontransactional hypotheses such as parental manipulation and kin recognition errors are discussed. PMID:16670991

Nonacs, Peter; Liebert, Aviva E; Starks, Philip T

2006-04-01

158

Transactional Skew and Assured Fitness Return Models Fail to Predict Patterns of Cooperation in Wasps  

Microsoft Academic Search

Cooperative breeders often exhibit reproductive skew, where dominant individuals reproduce more than subordinates. Two approaches derived from Hamilton's inclusive fitness model predict when subordinate behavior is favored over living solitarily. The as- sured fitness return (AFR) model predicts that subordinates help when they are highly likely to gain immediate indirect fitness. Trans- actional skew models predict dominants and subordinates \\

Peter Nonacs

2006-01-01

159

Flexible Skew-Symmetric Shape Model for Shape Representation, Classification, and Sampling  

Microsoft Academic Search

Skewness of shape data often arises in applications (e.g., medical image analysis) and is usually overlooked in statistical shape models. In such cases, a Gaussian assumption is unrealistic and a formulation of a general shape model which accounts for skewness is in order. In this paper, we present a novel statistical method for shape modeling, which we refer to as

Sajjad H. Baloch; Hamid Krim

2007-01-01

160

Method for generating skewed random numbers using two overlapping uniform distributions.  

National Technical Information Service (NTIS)

The objective of this work was to implement and evaluate a method for generating skewed random numbers using a combination of uniform random numbers. The method provides a simple and accurate way of generating skewed random numbers from the specified firs...

D. L. Ermak J. S. Nasstrom

1995-01-01

161

Skew detection and correction of ancient Tamil documents using particle swarm optimization  

NASA Astrophysics Data System (ADS)

When a document is fed to a scanner either mechanically or by a human operator for digitization, it suffers from some degrees of skew or tilt. Skew detection is one of the first operations to be applied to scanned documents when converting data to a digital format. Its aim is to align an image before processing because text segmentation and recognition methods require properly aligned lines. This paper presents a new approach for skew detection and correction of documents. Particle Swarm Optimization (PSO) is used for solving skew optimization. A new objective function based on local maxima and minima of projection profile is formulated and PSO is used to find the best angle that maximizes the objective function. The proposed method is compared with existing methods like Hough transform, Fourier transform. Experimental results show that the proposed method corrects the skew with the maximum error rate of +/- 1° .

Sridevi, N.; Subashini, P.

2012-04-01

162

Bay Bridge 360  

NSDL National Science Digital Library

This website was created by the various California transportation agencies that are involved in the enormous job of retrofitting the San Francisco-Oakland Bay Bridge to protect it from being damaged by seismic activity. It is an extremely well thought out website, with an interactive aerial graphic of the Bridge on its homepage that introduces visitors to their work. If you click on the colored circles on the bridge, you can see a slideshow of the construction on that section of the Bridge, and some of the Bridge sections include a time-lapse video of the construction. Additionally, there is a short film visitors can watch to get an overview of the project, by clicking on the blue circle above "Bay Bridge Overview" in the right-hand corner of the homepage. Clicking on the arrow in the left-hand corner of the homepage takes you inside the website where you can find links to "Closures and Detours", "Environmental Issues", for the Final Environmental Impact Statement, detailed explanations of the construction methods under the "Information Center" link, and even "Construction Cams". If you just can't get enough of traffic where you live, just click on "Construction Cams" and see Bay Bridge traffic.

2009-06-08

163

Wheatstone Bridge Learning Module  

NSDL National Science Digital Library

This page from the Southwest Center for Microsystems Education features a learning module on the electronic circuitry of a Wheatstone bridge. After completing the unit, students will be able to define the variable components of the Wheatstone bridge and describe how it works.A participant guide, instructor guide (both in PDF format) and two Power Point presentations (one on the Wheatstone bridge and another with a pressure sensor activity) are included. Users are encouraged to register and log in in order to access the full content on the site.

2011-10-11

164

Skew harmonics suppression in electromagnets with application to the Advanced Light Source (ALS) storage ring corrector magnet design.  

National Technical Information Service (NTIS)

An analytical expression for prediction of skew harmonics in an iron core combined function regular/skew dipole magnet due to arbitrarily positioned electromagnet coils is developed. A structured approach is presented for the suppression of an arbitrary n...

R. Schlueter K. Halbach

1993-01-01

165

Implant-Supported Bridge  

MedlinePLUS

... dental lab. Porcelain-fused-to-metal bridge The restoration (the part that looks like teeth) is a ... who has advanced training in the placement and restoration of implants. Your dentist will do a comprehensive ...

166

Magnetic Bridge Proximity Sensor.  

National Technical Information Service (NTIS)

A proximity sensor for indicating the spatial proximity of a ferrous object comprising a magnetic reluctance bridge formed from a plurality of high and low permeability sections and with a ring core flux gate magnetometer disposed therebetween to form the...

F. W. Heemstra

1982-01-01

167

Clinical Study of Myocardial Bridge  

Microsoft Academic Search

Background and Objectives:Myocardial bridge is a congenital coronary anomaly that causes myocardial ischemia by a milking effect. The general study of myocardial bridge is weak, therefore we retrospectively examined clinical records of cases of myocardial bridge. Materials and Method:This study included 36 bridge cases out of 1048 patients who underwent coronary angiography due to chest pain from Jan. 1993 to

Kil Hyun Cho; Jun Yong Jung; Jin Ho Song; Jong Cheol Ryu; Doo Il Kim; Dong Soo Kim

168

Germ Cell Intercellular Bridges  

PubMed Central

Stable intercellular bridges are a conserved feature of gametogenesis in multicellular animals observed more than 100 years ago, but their function was unknown. Many of the components necessary for this structure have been identified through the study of cytokinesis in Drosophila; however, mammalian intercellular bridges have distinct properties from those of insects. Mammalian germ cell intercellular bridges are composed of general cytokinesis components with additional germ cell–specific factors including TEX14. TEX14 is an inactive kinase essential for the maintenance of stable intercellular bridges in gametes of both sexes but whose loss specifically impairs male meiosis. TEX14 acts to impede the terminal steps of abscission by competing for essential component CEP55, blocking its interaction in nongerm cells with ALIX and TSG101. Additionally, TEX14-interacting protein RBM44, whose localization in stabile intercellular bridges is limited to pachytene and secondary spermatocytes, may participate in processes such as RNA transport but is nonessential to the maintenance of intercellular bridge stability.

Greenbaum, Michael P.; Iwamori, Tokuko; Buchold, Gregory M.; Matzuk, Martin M.

2011-01-01

169

Log Pearson type 3 quantile estimators with regional skew information and low outlier adjustments  

USGS Publications Warehouse

[1] The recently developed expected moments algorithm (EMA) [Cohn et al., 1997] does as well as maximum likelihood estimations at estimating log-Pearson type 3 (LP3) flood quantiles using systematic and historical flood information. Needed extensions include use of a regional skewness estimator and its precision to be consistent with Bulletin 17B. Another issue addressed by Bulletin 17B is the treatment of low outliers. A Monte Carlo study compares the performance of Bulletin 17B using the entire sample with and without regional skew with estimators that use regional skew and censor low outliers, including an extended EMA estimator, the conditional probability adjustment (CPA) from Bulletin 17B, and an estimator that uses probability plot regression (PPR) to compute substitute values for low outliers. Estimators that neglect regional skew information do much worse than estimators that use an informative regional skewness estimator. For LP3 data the low outlier rejection procedure generally results in no loss of overall accuracy, and the differences between the MSEs of the estimators that used an informative regional skew are generally modest in the skewness range of real interest. Samples contaminated to model actual flood data demonstrate that estimators which give special treatment to low outliers significantly outperform estimators that make no such adjustment.

Griffis, V. W.; Stedinger, J. R.; Cohn, T. A.

2004-01-01

170

Skew estimation of natural images based on a salient line detector  

NASA Astrophysics Data System (ADS)

When the horizon or long edges are skewed in photos, they may seem unstable unless they are artistic intentions, and hence we may wish to correct the skews. For the skew correction of faint as well as strong horizons, we propose a skew estimation method for natural images. We first apply a long-block-based edge detector that can construct edge maps even when the edge is faint and/or background is cluttered. We also propose a robust line-detection method that uses the generated edge map, based on progressive probabilistic Hough transform followed by refinement steps. For each of the detected lines, we define their weight and estimate the image skew based on the weighted votes from the lines. Since all the pixels in the long-blocks are used for the edge-map construction, the proposed method can find noisy or faint lines while rejecting curved or short lines. Experimental results show that the first salient angle corresponds with the image skew in most cases, and the skews are successfully corrected.

Koo, Hyung Il; Cho, Nam Ik

2013-01-01

171

Statistics on Cannabis Users Skew Perceptions of Cannabis Use  

PubMed Central

Collecting information about the prevalence of cannabis use is necessary but not sufficient for understanding the size, dynamics, and outcomes associated with cannabis markets. This paper uses two data sets describing cannabis consumption in the United States and Europe to highlight (1) differences in inferences about sub-populations based on the measure used to quantify cannabis-related activity; (2) how different measures of cannabis-related activity can be used to more accurately describe trends in cannabis usage over time; and (3) the correlation between frequency of use in the past-month and average grams consumed per use-day. Key findings: focusing on days of use instead of prevalence shows substantially greater increases in U.S. cannabis use in recent years; however, the recent increase is mostly among adults, not youth. Relatively more rapid growth in use days also occurred among the college-educated and Hispanics. Further, data from a survey conducted in seven European countries show a strong positive correlation between frequency of use and quantity consumed per day of use, suggesting consumption is even more skewed toward the minority of heavy users than is suggested by days-of-use calculations.

Burns, Rachel M.; Caulkins, Jonathan P.; Everingham, Susan S.; Kilmer, Beau

2013-01-01

172

Skewed Distribution of Natural Killer Cells in Psoriasis Skin Lesions  

PubMed Central

Background Psoriasis is a hyper-proliferative disease of the skin in which immunological mechanisms play a direct pathogenetic role. There have been limited studies of natural killer (NK) cells in psoriasis. Objectives To examine the phenotype of NK cells in skin biopsies and peripheral blood mononuclear cells from patients with psoriasis and healthy controls. Methods CD56+CD16? and CD56+CD16+ NK cells were isolated from lesional skin, unaffected skin and PBMC of psoriasis patients, and normal skin and PBMC from healthy controls. The expression of CD57, NKG2A, and NKG2C was assessed by flow cytometry. Results NK cells in psoriasis skin lesions were skewed in their expression of CD57, a marker of NK cell maturity, with CD57 expression significantly reduced and NKG2A expression increased on NK cells in lesional and unaffected skin compared to controls. Conclusions These data suggest that in this patient cohort NK cells could be isolated from psoriasis lesions and exhibit an immature phenotype.

Batista, M. D.; Ho, E. L.; Kuebler, P. J.; Milush, J. M.; Lanier, L. L.; Kallas, E. G.; York, V. A.; Chang, D.; Liao, W.; Unemori, P.; Leslie, K. S.; Maurer, T.; Nixon, D. F.

2013-01-01

173

Regression for Skewed Biomarker Outcomes Subject to Pooling  

PubMed Central

Summary Epidemiological studies involving biomarkers are often hindered by prohibitively expensive laboratory tests. Strategically pooling specimens prior to performing these lab assays has been shown to effectively reduce cost with minimal information loss in a logistic regression setting. When the goal is to perform regression with a continuous biomarker as the outcome, regression analysis of pooled specimens may not be straightforward, particularly if the outcome is right-skewed. In such cases, we demonstrate that a slight modification of a standard multiple linear regression model for poolwise data can provide valid and precise coefficient estimates when pools are formed by combining biospecimens from subjects with identical covariate values. When these x-homogeneous pools cannot be formed, we propose a Monte Carlo Expectation Maximization (MCEM) algorithm to compute maximum likelihood estimates (MLEs). Simulation studies demonstrate that these analytical methods provide essentially unbiased estimates of coefficient parameters as well as their standard errors when appropriate assumptions are met. Furthermore, we show how one can utilize the fully observed covariate data to inform the pooling strategy, yielding a high level of statistical efficiency at a fraction of the total lab cost.

Mitchell, Emily M.; Lyles, Robert H.; Manatunga, Amita K.; Danaher, Michelle; Perkins, Neil J.; Schisterman, Enrique F.

2014-01-01

174

Estimating generalized skew of the log-Pearson Type III distribution for annual peak floods in Illinois  

USGS Publications Warehouse

Four techniques for estimating generalized skew in Illinois were evaluated: (1) a generalized skew map of the US; (2) an isoline map; (3) a prediction equation; and (4) a regional-mean skew. Peak-flow records at 730 gaging stations having 10 or more annual peaks were selected for computing station skews. Station skew values ranged from -3.55 to 2.95, with a mean of -0.11. Frequency curves computed for 30 gaging stations in Illinois using the variations of the regional-mean skew technique are similar to frequency curves computed using a skew map developed by the US Water Resources Council (WRC). Estimates of the 50-, 100-, and 500-yr floods computed for 29 of these gaging stations using the regional-mean skew techniques are within the 50% confidence limits of frequency curves computed using the WRC skew map. Although the three variations of the regional-mean skew technique were slightly more accurate than the WRC map, there is no appreciable difference between flood estimates computed using the variations of the regional-mean technique and flood estimates computed using the WRC skew map. (Peters-PTT)

Oberg, Kevin A.; Mades, Dean M.

1987-01-01

175

Skewness in large-scale structure and non-Gaussian initial conditions  

NASA Technical Reports Server (NTRS)

We compute the skewness of the galaxy distribution arising from the nonlinear evolution of arbitrary non-Gaussian intial conditions to second order in perturbation theory including the effects of nonlinear biasing. The result contains a term identical to that for a Gaussian initial distribution plus terms which depend on the skewness and kurtosis of the initial conditions. The results are model dependent; we present calculations for several toy models. At late times, the leading contribution from the initial skewness decays away relative to the other terms and becomes increasingly unimportant, but the contribution from initial kurtosis, previously overlooked, has the same time dependence as the Gaussian terms. Observations of a linear dependence of the normalized skewness on the rms density fluctuation therefore do not necessarily rule out initially non-Gaussian models. We also show that with non-Gaussian initial conditions the first correction to linear theory for the mean square density fluctuation is larger than for Gaussian models.

Fry, J. N.; Scherrer, Robert J.

1994-01-01

176

Simulation of twin data controlling population mean, variance, skewness and kurtosis.  

PubMed

A computer system for simulation of quantitative twin data is being developed. The capability is being built in a simulate distributions with known means, standard deviations, skewness and kurtosis. PMID:562055

Christian, J C; Bailey, J E; Evans, M M; Kang, K W; Norton, J A; Yu, P L

1977-01-01

177

Pennsylvania Covered Bridges  

NSDL National Science Digital Library

Covered bridges cause moments of delight for historic preservationists, and they entered a new place in American popular culture when they figured prominently in a certain Clint Eastwood film in the early 1990s. Recently, staff members and student assistants at Bucknell University spent a significant amount of time creating this digital collection of covered bridge photographs. Interestingly enough, the original photographs were taken by a long-time member of the biology faculty at Bucknell, one Professor Nelson F. Davis. The photos date from 1898 to 1939, and all told, there are over 300 images in this collection. Visitors will enjoy looking over this collection, and these documents will be of great interest to anyone fascinated by these types of bridges, engineering, or the history of rural Pennsylvania.

178

The aesthetic composite bridge.  

PubMed

New developments are constantly introduced in the search for the optimal treatment modality to restore a single anterior tooth. The patient attention has shifted to aesthetics of the restoration, biocompatibility of the dental materials utilized, conservative preparation of the teeth to be restored, and the retention of intact adjacent dentition. The learning objective of this article is to review the methods currently utilized and to present a recently introduced treatment modality--the two-component bridge, which combines the strength and resiliency of composite resin with the aesthetic advantages of porcelain. The technology of the material is reviewed, the predominantly lingual tooth preparation procedures are outlined, and the bridge try-in is described. The advantages of the two-component bridge are presented along with the contraindications and suggestions of careful case selection. Three cases with congenitally missing maxillary lateral incisors in youthful patients are presented to supplement the theoretical outline and to describe and illustrate the clinical procedure. PMID:9550061

Feinman, R A

1997-01-01

179

Dog Bridge, view of the deck of the bridge and ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Dog Bridge, view of the deck of the bridge and rails looking from Linden Lane - National Park Seminary, Bounded by Capitol Beltway (I-495), Linden Lane, Woodstove Avenue, & Smith Drive, Silver Spring, Montgomery County, MD

180

A fast algorithm for skew detection of document images using morphology  

Microsoft Academic Search

.   Any paper document when converted to electronic form through standard digitizing devices, like scanners, is subject to a\\u000a small tilt or skew. Meanwhile, a de-skewed document allows a more compact representation of its components, particularly text\\u000a objects, such as words, lines, and paragraphs, where they can be represented by their rectilinear bounding boxes. This simplified\\u000a representation leads to more

Amit Kumar Das; Bhabatosh Chanda

2001-01-01

181

Bridg.me  

NSDL National Science Digital Library

What if you could have a conference call that called you? Such a thing is now possible courtesy of Bridg.me. Apparently one of the co-founders of Bridg.me was never on time for meetings and conferences, so this handy website was created to solve the problem. Visitors just need to register online, put a meeting in their Google Calendar, and the conference will call them at the appointed hour and minute. It's quite easy to use and it's compatible with all operating systems.

182

Genetic Architecture of Skewed X Inactivation in the Laboratory Mouse  

PubMed Central

X chromosome inactivation (XCI) is the mammalian mechanism of dosage compensation that balances X-linked gene expression between the sexes. Early during female development, each cell of the embryo proper independently inactivates one of its two parental X-chromosomes. In mice, the choice of which X chromosome is inactivated is affected by the genotype of a cis-acting locus, the X-chromosome controlling element (Xce). Xce has been localized to a 1.9 Mb interval within the X-inactivation center (Xic), yet its molecular identity and mechanism of action remain unknown. We combined genotype and sequence data for mouse stocks with detailed phenotyping of ten inbred strains and with the development of a statistical model that incorporates phenotyping data from multiple sources to disentangle sources of XCI phenotypic variance in natural female populations on X inactivation. We have reduced the Xce candidate 10-fold to a 176 kb region located approximately 500 kb proximal to Xist. We propose that structural variation in this interval explains the presence of multiple functional Xce alleles in the genus Mus. We have identified a new allele, Xcee present in Mus musculus and a possible sixth functional allele in Mus spicilegus. We have also confirmed a parent-of-origin effect on X inactivation choice and provide evidence that maternal inheritance magnifies the skewing associated with strong Xce alleles. Based on the phylogenetic analysis of 155 laboratory strains and wild mice we conclude that Xcea is either a derived allele that arose concurrently with the domestication of fancy mice but prior the derivation of most classical inbred strains or a rare allele in the wild. Furthermore, we have found that despite the presence of multiple haplotypes in the wild Mus musculus domesticus has only one functional Xce allele, Xceb. Lastly, we conclude that each mouse taxa examined has a different functional Xce allele.

Calaway, John D.; Lenarcic, Alan B.; Didion, John P.; Wang, Jeremy R.; Searle, Jeremy B.; McMillan, Leonard; Valdar, William; Pardo-Manuel de Villena, Fernando

2013-01-01

183

Opposite GC skews at the 5' and 3' ends of genes in unicellular fungi  

PubMed Central

Background GC-skews have previously been linked to transcription in some eukaryotes. They have been associated with transcription start sites, with the coding strand G-biased in mammals and C-biased in fungi and invertebrates. Results We show a consistent and highly significant pattern of GC-skew within genes of almost all unicellular fungi. The pattern of GC-skew is asymmetrical: the coding strand of genes is typically C-biased at the 5' ends but G-biased at the 3' ends, with intermediate skews at the middle of genes. Thus, the initiation, elongation, and termination phases of transcription are associated with different skews. This pattern influences the encoded proteins by generating differential usage of amino acids at the 5' and 3' ends of genes. These biases also affect fourfold-degenerate positions and extend into promoters and 3' UTRs, indicating that skews cannot be accounted by selection for protein function or translation. Conclusions We propose two explanations, the mutational pressure hypothesis, and the adaptive hypothesis. The mutational pressure hypothesis is that different co-factors bind to RNA pol II at different phases of transcription, producing different mutational regimes. The adaptive hypothesis is that cytidine triphosphate deficiency may lead to C-avoidance at the 3' ends of transcripts to control the flow of RNA pol II molecules and reduce their frequency of collisions.

2011-01-01

184

The effect of skewness and kurtosis on the Kenward-Roger approximation when group distributions differ.  

PubMed

Background: This study examined the independent effect of skewness and kurtosis on the robustness of the linear mixed model (LMM), with the Kenward-Roger (KR) procedure, when group distributions are different, sample sizes are small, and sphericity cannot be assumed. Methods: A Monte Carlo simulation study considering a split-plot design involving three groups and four repeated measures was performed. Results: The results showed that when group distributions are different, the effect of skewness on KR robustness is greater than that of kurtosis for the corresponding values. Furthermore, the pairings of skewness and kurtosis with group size were found to be relevant variables when applying this procedure. Conclusions: With sample sizes of 45 and 60, KR is a suitable option for analyzing data when the distributions are: (a) mesokurtic and not highly or extremely skewed, and (b) symmetric with different degrees of kurtosis. With total sample sizes of 30, it is adequate when group sizes are equal and the distributions are: (a) mesokurtic and slightly or moderately skewed, and sphericity is assumed; and (b) symmetric with a moderate or high/extreme violation of kurtosis. Alternative analyses should be considered when the distributions are highly or extremely skewed and samples sizes are small. PMID:24755032

Arnau, Jaime; Bendayan, Rebecca; Blanca, María J; Bono, Roser

2014-05-01

185

16. LOG AND PLANK BRIDGE ON ACCESS ROAD NEAR BRIDGE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. LOG AND PLANK BRIDGE ON ACCESS ROAD NEAR BRIDGE SITE; SAME STRUCTURE AS SHOWN IN PHOTO #12. ZION NP NEGATIVE NO. 967 ZIO. - Zion-Mount Carmel Highway, Virgin River Bridge, Spanning North Fork of Virgin River on Zion-Mount Carmel Highway, Springdale, Washington County, UT

186

1. WESTERN VIEW OF BRIDGE PLAZA, SHOWING MEMORIAL BRIDGE AT ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. WESTERN VIEW OF BRIDGE PLAZA, SHOWING MEMORIAL BRIDGE AT LEFT AND THE ROCK CREEK AND POTOMAC PARKWAY RAMP AT RIGHT. VIEW TAKEN FROM THE REAR OF THE LINCOLN MEMORIAL. - Arlington Memorial Bridge, Boundary Channel Extension, Spanning Mount Vernon Memorial Highway & Boundary Channel, Washington, District of Columbia, DC

187

Retrofitted Bridge Fragility Analysis for Typical Classes of Multispan Bridges  

Microsoft Academic Search

Retrofitted bridge fragility curves provide a powerful tool for assessing the effect of retrofit measures on the seismic performance of different bridge types under a range of loading levels. Traditional methods for retrofit assessment typically evaluate the effectiveness of retrofit based on the performance of individual components. However, the use of fragility curves for retrofitted bridges has the ability to

Jamie E. Padgett; Reginald DesRoches

2009-01-01

188

Bridge Types: Tensile & Compressive Forces  

NSDL National Science Digital Library

Students explore how tension and compression forces act on three different bridge types. Using sponges, cardboard and string, they create models of beam, arch and suspension bridges and apply forces to understand how they disperse or transfer these loads.

Integrated Teaching And Learning Program

189

Energy Harvesting on Highway Bridges.  

National Technical Information Service (NTIS)

This project is investigating the potential for generating electrical power from the vibrations of a bridge due to large vehicles. It utilizes state-of-the-art technology and interdisciplinary expertise in solid-state electronics and bridge engineering to...

J. Nolan J. D. Baldwin L. Holliday S. Roswurm

2011-01-01

190

Bridge Design, Testing, and Evaluation.  

National Technical Information Service (NTIS)

The 16 papers in this report deal with the following areas: analysis of a horizontally curved bridge through a geometric structural model; (abridgment) thermal stresses and deformations in nonprismatic indeterminate composite bridges; (abridgment) thermal...

1976-01-01

191

Bridging The Resource Gap.  

National Technical Information Service (NTIS)

With the Department of Defense under the scrutiny of the American public and the media always nearby, how should the military best prepare the leaders of tomorrow to cope with change during fiscally austere times. In my opinion, the key to bridging what I...

A. H. Villarreal

1995-01-01

192

Bridging the Gaps.  

ERIC Educational Resources Information Center

Discusses a model water quality monitoring project, Project Bridge, established to train minority girls about to enter eighth grade in scientific procedures followed by hands-on experimentation. Students spent a week monitoring water in an urban stream and analyzing results. (LZ)

Netzer, Greg

1995-01-01

193

Design Squad: Suspension Bridge  

NSDL National Science Digital Library

In this video segment adapted from Design Squad—a PBS TV series featuring high school contestants tackling engineering challenges—students employ the concepts of tension and compression to build a suspension bridge without the aid of power tools.

Foundation, Wgbh E.

2007-08-09

194

Design Squad: Truss Bridge  

NSDL National Science Digital Library

In this video segment adapted from Design Squad—a PBS TV series featuring high school contestants tackling engineering challenges—students employ the concepts of tension and compression as they build a truss bridge without the aid of power tools.

Foundation, Wgbh E.

2007-08-09

195

Virtual Bridge Design  

ERIC Educational Resources Information Center

The West Point Bridge Design (WPBD) building project engages students in project-based learning by giving them a real-life problem to solve. By using technology, students are able to become involved in solving problems that they normally would not encounter. Involvement with interactive websites, such as WPBD, assists students in using…

Bisogno, Janet; JeanPierre, Bobby

2008-01-01

196

Bridging the Gap.  

ERIC Educational Resources Information Center

Describes interdisciplinary activities with real-world applications ranging from science to mathematics to technology. Cites the study and construction of model bridges as a way for students to learn about engineering concepts and some of their relationships. States that the exercise enhanced teacher cooperation between the different fields. (RT)

Kroto, Joseph J.

1988-01-01

197

Bridge Deck Drainage Guidelines.  

National Technical Information Service (NTIS)

The document presents criteria to determine if bridge drainage scuppers and drains are required. A design nomograph allows a rapid decision to be made. A key variable, design rain intensity, is analyzed: the rational method is reviewed and new methods for...

G. K. Young J. Phillippe S. J. Bellomo J. Normann W. E. Hughes

1986-01-01

198

CMOS Bridging Fault Detection  

Microsoft Academic Search

The authors compare the performance of two test generation techniques, stuck fault testing and current testing, when applied to CMOS bridging faults. Accurate simulation of such faults mandated the development of several new design automation tools, including an analog-digital fault simulator. The results of this simulation are analyzed. It is shown that stuck fault test generation, while inherently incapable of

Thomas M. Storey; Wojciech Maly

1990-01-01

199

Bridging the Gap?  

ERIC Educational Resources Information Center

The political context of the conversion of the Historic Tramway Bridge, adjacent to Sandon Point in Bulli (NSW, Australia), and how this was exploited to serve predetermined ends, illustrates that technologies can be designed to have particular social (and political) effects. Through reflection on this relatively small engineering project, this…

Salter, Colin

2009-01-01

200

The Bridge to Somewhere  

ERIC Educational Resources Information Center

Since its inception in 2000, Pan-Asian American Community House's (PAACH's) education mission has bridged Asian-American studies to student life. PAACH initiatives have helped spread Asian-American diaspora to thousands of students at the University of Pennsylvania. They have also helped students determine for themselves what it means to be a…

Lum, Lydia

2009-01-01

201

Quantum Bidding in Bridge  

NASA Astrophysics Data System (ADS)

Quantum methods allow us to reduce communication complexity of some computational tasks, with several separated partners, beyond classical constraints. Nevertheless, experimental demonstrations of this have thus far been limited to some abstract problems, far away from real-life tasks. We show here, and demonstrate experimentally, that the power of reduction of communication complexity can be harnessed to gain an advantage in a famous, immensely popular, card game—bridge. The essence of a winning strategy in bridge is efficient communication between the partners. The rules of the game allow only a specific form of communication, of very low complexity (effectively, one has strong limitations on the number of exchanged bits). Surprisingly, our quantum technique does not violate the existing rules of the game (as there is no increase in information flow). We show that our quantum bridge auction corresponds to a biased nonlocal Clauser-Horne-Shimony-Holt game, which is equivalent to a 2?1 quantum random access code. Thus, our experiment is also a realization of such protocols. However, this correspondence is not complete, which enables the bridge players to have efficient strategies regardless of the quality of their detectors.

Muhammad, Sadiq; Tavakoli, Armin; Kurant, Maciej; Paw?owski, Marcin; ?ukowski, Marek; Bourennane, Mohamed

2014-04-01

202

Semiconductor Bridge Cable Tests.  

National Technical Information Service (NTIS)

The semiconductor bridge (SCB) is an electroexplosive device used to initiate detonators. A C cable is commonly used to connect the SCB to a firing set (FS). A series of tests were performed to identify smaller, lighter cables for firing single and multip...

T. L. King

2002-01-01

203

Semiconductor Bridge Cable Test  

Microsoft Academic Search

The semiconductor bridge (SCB) is an electroexplosive device used to initiate detonators. A C cable is commonly used to connect the SCB to a firing set. A series of tests were performed to identify smaller, lighter cables for firing single and multiple SCBs. This report provides a description of these tests and their results. It was demonstrated that lower threshold

TONY L

2002-01-01

204

Semiconductor bridge (SCB) igniter  

Microsoft Academic Search

An explosive device is described comprising: a non electrically conducting substrate; an electrical material mounted on the substrate and having a negative temperature coefficient of electrical resistivity at an elevated temperature. The material covers an area of the substrate and defines a pair of spaced pads connected by a bridge; a metallized layer covering each of the spaced pads; an

R. W. Jr. Bickes; A. C. Schwartz

1987-01-01

205

BUILDING BRIDGES IN HEALTHCARE  

Microsoft Academic Search

or those who have not been in the Charleston area for several years, 2005 has marked the opening of a fabulous new span that links Charleston with Mount Pleasant. In mid July, the entire region turned out to stroll over the new bridges and celebrate their completion with a monumental fireworks display. The two dilapidated structures that had offered an

Bill Hueston

206

Jointless Bridge Decks.  

National Technical Information Service (NTIS)

The major focus of this research was to validate the concept of connecting two adjacent simple-span girders with a link slab to form a jointless bridge deck so as to eliminate the standard deck joint between the girders. Laboratory tests were conducted on...

P. Zia A. Caner A. K. El-Safty

1995-01-01

207

Tech Prep Bridge Programs.  

ERIC Educational Resources Information Center

Although tech prep is still in its infancy in Georgia, increasing numbers of students are entering technical institutes after having completed the secondary-level component of tech prep programs. Georgia's technical institutes must begin the process of developing bridge programs to help adult students with no tech prep experience develop academic…

Gohdes, William

1995-01-01

208

Bridging Disciplinary Boundaries  

ERIC Educational Resources Information Center

Interdisciplinary education promotes the unity of knowledge by bridging the cultural divide between the social constructs of disciplines and encourages the development of knowledge to enhance society. As an inquiry-based and relevant approach that expands and advances knowledge, interdisciplinary education facilitates creativity and flexibility,…

Mei, Linda

2009-01-01

209

JHU Bridge Designer  

NSDL National Science Digital Library

The Bridge Designer is a web-based program that allows the user to design and analyze 2-Dimensional statically determinate trusses. The user can specify support types (fixed or rolling) and locations, as well as the locations of various truss nodes and members.

Karweit, Michael

210

Tension roofs and bridges  

Microsoft Academic Search

The term ‘Tension Structures’ is commonly used for those structures wherein one or more primary load bearing elements are in tension. Such structures include membrane roofs, cable roofs, cable bridges, guyed masts or towers, cooling towers though some of these are less common. The tension elements are strands, ropes or membranes, which have to combine with structural elements carrying compression,

P Krishna

2001-01-01

211

A Guide to Covered Bridges  

NSDL National Science Digital Library

A Guide to Covered Bridges, offered by Drexel University, Philadelphia, Pennsylvania, transforms the Web into a time machine. Find the answer to the question, why are there so many covered bridges, and why in Pennsylvania and the Northeast? The Drexel University Honors Program sponsors this guide to dozens of covered bridges of the Philadelphia region. Driving tours are suggested, and bridge images are indexed by season (fall color, winter, snow and ice, spring/summer) and structure as well as county.

212

77 FR 16784 - General Bridge Regulation; Amendment  

Federal Register 2010, 2011, 2012, 2013

...USCG-2008-1188] RIN 1625-AB36 General Bridge Regulation; Amendment AGENCY: Coast...rulemaking concerning amendments to the general bridge regulations. The rulemaking was initiated...clarify the statutory responsibilities of bridge owners to remove their bridges from...

2012-03-22

213

Construction of an Experimental Segmental Bridge.  

National Technical Information Service (NTIS)

Concrete segmental bridge construction seems to offer many advantages over other types of bridge construction both in bridge replacement programs and in new bridge programs. This report discusses the construction process of the experimental segmental brid...

R. M. McClure H. R. Thomas J. E. Kehler

1980-01-01

214

Standard Plans for Southern Pine Bridges.  

National Technical Information Service (NTIS)

This publication contains standardized designs and details for three timber bridge superstructure types, including stress-laminated sawn lumber bridges, stress laminated glued laminated timber (glulam) bridges, and longitudinal sawn lumber stringer bridge...

M. Triche M. A. Ritter P. D. Hilbrich Lee

1995-01-01

215

Wikipedia: Cable-Stayed Bridge  

NSDL National Science Digital Library

This site contains a description of cable-stayed bridges and their advantages, illustrated by numerous photographs. It has a thorough explanation of the differences between the cable-stayed bridge and the suspension bridge, both in design and in the manner of construction. Variations and related types are shown, and links are included to a large number of examples.

2006-07-01

216

Fibre reinforced composite dental bridge  

Microsoft Academic Search

This experimental investigation aims at revealing the mechanical behaviour and failure pattern of direct fibre-reinforced resin-bonded dental bridge with various designs. To evaluate the overall effects of some newly developed dental materials, in the experiment, genuine composite dental bridge specimens are prepared and tested. The ultimate load, stiffness and mode at the failure of the bridges are measured and compared

W. Li; M. V. Swain; Q. Li; J. Ironside; G. P. Steven

2004-01-01

217

Cracks in Concrete Bridge Decks.  

National Technical Information Service (NTIS)

A study of cracks in bridge decks as reported in the literature and observed in NSW shows that certain types of cracks are predominant in particular bridge types. Cracks in composite bridges and in cast-in-place kerbs and cantilever deck slabs are shown t...

D. Campbell-Allen B. Lau

1978-01-01

218

Static performance investigation of a skewed-throat multiaxis thrust-vectoring nozzle concept  

NASA Technical Reports Server (NTRS)

The static performance of a jet exhaust nozzle which achieves multiaxis thrust vectoring by physically skewing the geometric throat has been characterized in the static test facility of the 16-Foot Transonic Tunnel at NASA Langley Research Center. The nozzle has an asymmetric internal geometry defined by four surfaces: a convergent-divergent upper surface with its ridge perpendicular to the nozzle centerline, a convergent-divergent lower surface with its ridge skewed relative to the nozzle centerline, an outwardly deflected sidewall, and a straight sidewall. The primary goal of the concept is to provide efficient yaw thrust vectoring by forcing the sonic plane (nozzle throat) to form at a yaw angle defined by the skewed ridge of the lower surface contour. A secondary goal is to provide multiaxis thrust vectoring by combining the skewed-throat yaw-vectoring concept with upper and lower pitch flap deflections. The geometric parameters varied in this investigation included lower surface ridge skew angle, nozzle expansion ratio (divergence angle), aspect ratio, pitch flap deflection angle, and sidewall deflection angle. Nozzle pressure ratio was varied from 2 to a high of 11.5 for some configurations. The results of the investigation indicate that efficient, substantial multiaxis thrust vectoring was achieved by the skewed-throat nozzle concept. However, certain control surface deflections destabilized the internal flow field, which resulted in substantial shifts in the position and orientation of the sonic plane and had an adverse effect on thrust-vectoring and weight flow characteristics. By increasing the expansion ratio, the location of the sonic plane was stabilized. The asymmetric design resulted in interdependent pitch and yaw thrust vectoring as well as nonzero thrust-vector angles with undeflected control surfaces. By skewing the ridges of both the upper and lower surface contours, the interdependency between pitch and yaw thrust vectoring may be eliminated and the location of the sonic plane may be further stabilized.

Wing, David J.

1994-01-01

219

Molecular engineering with bridged polysilsesquioxanes  

SciTech Connect

Bridged polysilsesquioxanes are a class of hybrid organic-inorganic materials that permit molecular engineering of bulk properties including porosity. Prepared by sol-gel polymerization of monomers with two or more trialkoxysilyl groups, the materials are highly cross-linked amorphous polymers that are readily obtained as gels. The bridging configuration of the hydrocarbon group insures that network polymers are readily formed and that the organic functionality is homogeneously distributed throughout the polymeric scaffolding at the molecular level. This permits the bulk properties, including surface area, pore size, and dielectric constant to be engineered through the selection of the bridging organic group. Numerous bridging groups have been incorporated. This presentation will focus on the effects that the length, flexibility, and substitution geometry of the hydrocarbon bridging groups have on the properties of the resulting bridged polysilsesquioxanes. Details of the preparation, characterization, and some structure property relationships of these bridged polysilsesquioxanes will be given.

LOY,DOUGLAS A.; SHEA,KENNETH J.

2000-05-09

220

Electrical Actuation Technology Bridging  

NASA Technical Reports Server (NTRS)

This document contains the proceedings of the NASA Electrical Actuation Technology Bridging (ELA-TB) Workshop held in Huntsville, Alabama, September 29-October 1, 1992. The workshop was sponsored by the NASA Office of Space Systems Development and Marshall Space Flight Center (MSFC). The workshop addressed key technologies bridging the entire field of electrical actuation including systems methodology, control electronics, power source systems, reliability, maintainability, and vehicle health management with special emphasis on thrust vector control (TVC) applications on NASA launch vehicles. Speakers were drawn primarily from industry with participation from universities and government. In addition, prototype hardware demonstrations were held at the MSFC Propulsion Laboratory each afternoon. Splinter sessions held on the final day afforded the opportunity to discuss key issues and to provide overall recommendations. Presentations are included in this document.

Hammond, Monica (compiler); Sharkey, John (compiler)

1993-01-01

221

Bridging semiconductor and magnetism  

NASA Astrophysics Data System (ADS)

Carrier-induced ferromagnetism and its manipulation in Mn-doped III-V semiconductors, such as (In,Mn)As and (Ga,Mn)As, offer a wide variety of phenomena that originate from the interplay between magnetism and semiconducting properties, forming a bridge between semiconductor and magnetism. A review is given on the electrical manipulation of magnetism, its understanding, and potential applications both from the physics point of view and from the technological point of view. The electric-field study on magnetism is now being extended to magnetic metals, leading to an energy efficient way of magnetization reversal important for future semiconductor integrated circuit technology, yet another route to bridge semiconductor and magnetism in a fruitful way.

Ohno, H.

2013-04-01

222

A Simple 2-D Finite-Element Geometry for Analyzing Surface-Mounted Synchronous Machines With Skewed Rotor Magnets  

Microsoft Academic Search

We present a new 2-D FEM-based system for analyzing permanent-magnet surface-mounted synchronous machines with skewed rotor magnets. The system is based on generating a geometric equivalent non-skewed permanent-magnet distribution that accounts for the skewed distribution of the practical rotor. An appealing feature of the proposed system is that it can be easily performed in any 2-D electromagnetic FEM package by

Julio-César Urresty; J.-R. Riba Ruiz; Luís Romeral; Antonio Garcia

2010-01-01

223

Bridge-NOAA Collection  

NSDL National Science Digital Library

The Bridge-NOAA Collection is a selection of exemplary resources from the National Oceanic and Atmospheric Administration (NOAA) that have been reviewed by educators and found to be well-suited for educational purposes. The collection also emphasizes professional-development opportunities for teachers. There is a strong focus on research data and its use in teaching. The collection provides educators with accurate and useful information on global, national, and regional ocean-science topics.

2007-10-19

224

Generalized Skew Coefficients of Annual Peak Flows for Rural, Unregulated Streams in West Virginia  

USGS Publications Warehouse

Generalized skew was determined from analysis of records from 147 streamflow-gaging stations in or near West Virginia. The analysis followed guidelines established by the Interagency Advisory Committee on Water Data described in Bulletin 17B, except that stations having 50 or more years of record were used instead of stations with the less restrictive recommendation of 25 or more years of record. The generalized-skew analysis included contouring, averaging, and regression of station skews. The best method was considered the one with the smallest mean square error (MSE). MSE is defined as the following quantity summed and divided by the number of peaks: the square of the difference of an individual logarithm (base 10) of peak flow less the mean of all individual logarithms of peak flow. Contouring of station skews was the best method for determining generalized skew for West Virginia, with a MSE of about 0.2174. This MSE is an improvement over the MSE of about 0.3025 for the national map presented in Bulletin 17B.

Atkins, John T., Jr.; Wiley, Jeffrey B.; Paybins, Katherine S.

2009-01-01

225

Detection of Dark Matter Skewness in the VIRMOS-DESCART Survey: Implications for ?0  

NASA Astrophysics Data System (ADS)

Weak gravitational lensing provides a direct statistical measure of dark matter distribution. The variance is easiest to measure, which constrains the degenerate product ?8?0.60. The degeneracy is broken by measuring the skewness arising from the fact that densities must remain positive, which is not possible when the initially symmetric perturbations become nonlinear. Skewness measures the nonlinear mass scale, which in combination with the variance measures ?0 directly. We present the first detection of dark matter skewness from the VIRMOS-DESCART survey. We have measured the full three-point function and its projections onto windowed skewness. We separate the lensing mode and the B-mode. The lensing skewness is detected for a compensated Gaussian on scales of 5.37? to be ?3=(1.06+/-0.06)×10-6. The B-modes are consistent with zero at this scale. The variance for the same window function is ?2=(5.32+/-0.62+/-0.98)×10-5, resulting in S3=375+342-124. Comparing with N-body simulations, we find ?0<0.5 at 90% confidence. The Canada-France-Hawaii Telescope legacy survey and newer simulations should be able to improve significantly on the constraint.

Pen, Ue-Li; Zhang, Tongjie; van Waerbeke, Ludovic; Mellier, Yannick; Zhang, Pengjie; Dubinski, John

2003-08-01

226

Skew harmonics suppression in electromagnets with application to the Advanced Light Source (ALS) storage ring corrector magnet design  

SciTech Connect

An analytical expression for prediction of skew harmonics in an iron core combined function regular/skew dipole magnet due to arbitrarily positioned electromagnet coils is developed. A structured approach is presented for the suppression of an arbitrary number of harmonic components to arbitrarily low values. Application of the analytical harmonic strength calculations coupled to the structured harmonic suppression approach is presented in the context of the design of the ALS storage ring corrector magnets, where quadrupole, sextupole, and octupole skew harmonics were reduced to less than 1.0% of the skew dipole at the beam aperture radius r = 3.0 cm.

Schlueter, R.; Halbach, K.

1993-09-01

227

Skew-Laplace and Cell-Size Distribution in Microbial Axenic Cultures: Statistical Assessment and Biological Interpretation  

PubMed Central

We report a skew-Laplace statistical analysis of both flow cytometry scatters and cell size from microbial strains primarily grown in batch cultures, others in chemostat cultures and bacterial aquatic populations. Cytometry scatters best fit the skew-Laplace distribution while cell size as assessed by an electronic particle analyzer exhibited a moderate fitting. Unlike the cultures, the aquatic bacterial communities clearly do not fit to a skew-Laplace distribution. Due to its versatile nature, the skew-Laplace distribution approach offers an easy, efficient, and powerful tool for distribution of frequency analysis in tandem with the flow cytometric cell sorting.

Julia, Olga; Vidal-Mas, Jaume; Panikov, Nicolai S.; Vives-Rego, Josep

2010-01-01

228

Skew harmonics suppression in electromagnets with application to the advanced light source (ALS) storage ring corrector magnet design  

NASA Astrophysics Data System (ADS)

An analytical expression for prediction of skew harmonics in an iron core combined function regular/skew dipole magnet due to arbitrarily positioned electromagnet coils is developed. A structured approach is presented for the suppression of an arbitrary number of harmonic components to arbitrarily low values. Application of the analytical harmonic strength calculations coupled to the structured harmonic suppression approach is presented in the context of the design of the ALS storage ring corrector magnets, where quadrupole, sextupole, and octupole skew harmonics were reduced to less than 1.0% of the skew dipole at the beam aperture radius r = 3.0 cm.

Schlueter, R. D.; Halbach, K.

1994-07-01

229

Random Regression Models Based On The Skew Elliptically Contoured Distribution Assumptions With Applications To Longitudinal Data *  

PubMed Central

Bartolucci et al.(2003) extended the distribution assumption from the normal (Lyles et al., 2000) to the elliptical contoured distribution (ECD) for random regression models used in analysis of longitudinal data accounting for both undetectable values and informative drop-outs. In this paper, the random regression models are constructed on the multivariate skew ECD. A real data set is used to illustrate that the skew ECDs can fit some unimodal continuous data better than the Gaussian distributions or more general continuous symmetric distributions when the symmetric distribution assumption is violated. Also, a simulation study is done for illustrating the model fitness from a variety of skew ECDs. The software we used is SAS/STAT, V. 9.13.

Zheng, Shimin; Rao, Uma; Bartolucci, Alfred A.; Singh, Karan P.

2011-01-01

230

Modeling the effects of wave skewness and beach cusps on littoral sand transport  

USGS Publications Warehouse

A process-based numerical modeling system is utilized for predicting littoral sand transport. The intent is to examine conditions slightly more complex than linear waves impinging upon a plane beach. Two factors that we examine are wave skewness and longshore varying bathymetry. An empirical model is used for calculating the skewed bottom wave orbital velocity. The advection of sediment due to the skewed wave velocity is larger and in the direction of the waves, opposite to the results with sinusoidal wave velocities, due to the increase in the bottom shear stress under the wave crests. The model system is also applied to bathymetry containing beach cusps. When the wave field has relatively weak longshore wave power, the currents and the littoral transport exhibit significant longshore variability, thereby altering the overall mean littoral transport.

Haas, K. A.; Check, L. A.; Hanes, D. M.

2008-01-01

231

Isomonodromic deformations, generalized Knizhnik-Zamolodchikov equations and non-skew-symmetric classical r-matrices  

NASA Astrophysics Data System (ADS)

Using non-skew-symmetric classical r-matrices r12(u,v) with spectral parameters, we generalize Fuchsian systems and Schlesinger equations (isomonodromy equations) viewing the last as the nonautonomous Hamiltonian equations corresponding to the generalized Gaudin Hamiltonians. Quantizing these systems we construct generalization of Knizhnik-Zamolodchikov equations corresponding to the non-skew-symmetric classical r-matrices r12(u,v) with spectral parameters. In the case of an ordinary skew-symmetric classical r-matrix r12(u-v) depending on the difference of the spectral parameters, we reobtain, as special partial cases, a standard generalization of Fuchsian systems, Schlesinger, and Knizhnik-Zamolodchikov equations.

Skrypnyk, T.

2010-08-01

232

Atypical AT Skew in Firmicute Genomes Results from Selection and Not from Mutation  

PubMed Central

The second parity rule states that, if there is no bias in mutation or selection, then within each strand of DNA complementary bases are present at approximately equal frequencies. In bacteria, however, there is commonly an excess of G (over C) and, to a lesser extent, T (over A) in the replicatory leading strand. The low G+C Firmicutes, such as Staphylococcus aureus, are unusual in displaying an excess of A over T on the leading strand. As mutation has been established as a major force in the generation of such skews across various bacterial taxa, this anomaly has been assumed to reflect unusual mutation biases in Firmicute genomes. Here we show that this is not the case and that mutation bias does not explain the atypical AT skew seen in S. aureus. First, recently arisen intergenic SNPs predict the classical replication-derived equilibrium enrichment of T relative to A, contrary to what is observed. Second, sites predicted to be under weak purifying selection display only weak AT skew. Third, AT skew is primarily associated with largely non-synonymous first and second codon sites and is seen with respect to their sense direction, not which replicating strand they lie on. The atypical AT skew we show to be a consequence of the strong bias for genes to be co-oriented with the replicating fork, coupled with the selective avoidance of both stop codons and costly amino acids, which tend to have T-rich codons. That intergenic sequence has more A than T, while at mutational equilibrium a preponderance of T is expected, points to a possible further unresolved selective source of skew.

Charneski, Catherine A.; Honti, Frank; Bryant, Josephine M.

2011-01-01

233

Elevated Mortality among Birds in Chernobyl as Judged from Skewed Age and Sex Ratios  

PubMed Central

Background Radiation has negative effects on survival of animals including humans, although the generality of this claim is poorly documented under low-dose field conditions. Because females may suffer disproportionately from the effects of radiation on survival due to differences in sex roles during reproduction, radiation-induced mortality may result in male-skewed adult sex ratios. Methodology/Principal Finding We estimated the effects of low-dose radiation on adult survival rates in birds by determining age ratios of adults captured in mist nets during the breeding season in relation to background radiation levels around Chernobyl and in nearby uncontaminated control areas. Age ratios were skewed towards yearlings, especially in the most contaminated areas, implying that adult survival rates were reduced in contaminated areas, and that populations in such areas could only be maintained through immigration from nearby uncontaminated areas. Differential mortality in females resulted in a strongly male-skewed sex ratio in the most contaminated areas. In addition, males sang disproportionately commonly in the most contaminated areas where the sex ratio was male skewed presumably because males had difficulty finding and acquiring mates when females were rare. The results were not caused by permanent emigration by females from the most contaminated areas because none of the recaptured birds had changed breeding site, and the proportion of individuals with morphological abnormalities did not differ significantly between the sexes for areas with normal and higher levels of contamination. Conclusions/Significance These findings are consistent with the hypothesis that the adult survival rate of female birds is particularly susceptible to the effects of low-dose radiation, resulting in male skewed sex ratios at high levels of radiation. Such skewed age ratios towards yearlings in contaminated areas are consistent with the hypothesis that an area exceeding 30,000 km2 in Chernobyl’s surroundings constitutes an ecological trap that causes dramatic excess mortality.

M?ller, Anders Pape; Bonisoli-Alquati, Andrea; Rudolfsen, Geir; Mousseau, Timothy A.

2012-01-01

234

Modified Gelfand-Tseltin patterns, lattice permutations, and skew-tableau polynomials  

SciTech Connect

A modification of the well-known Gelfand-Tsetlin patterns, which are one-to-one with Young-Weyl standard tableaux is introduced. These new patterns are in one-to-one correspondence with skew-tableaux, and with a slight modification can be used to enumerate lattice permutations. In particular the coupling rule for angular momentum takes an elementary form in terms of these modified patterns. These interrelations will be presented, together with an outline of the construction of a class of polynomials that generalizes the skew Schur functions.

Louck, James D.

2002-01-01

235

Multivariate skew- t approach to the design of accumulation risk scenarios for the flooding hazard  

NASA Astrophysics Data System (ADS)

The multivariate version of the skew- t distribution provides a powerful analytical description of the joint behavior of multivariate processes. It enjoys valuable properties: from the aptitude to model skewed as well as leptokurtic datasets to the availability of moments and likelihood analytical expressions. Moreover, it offers a wide range of extremal dependence strength, allowing for upper and lower tail dependence. The idea underneath this work is to employ the multivariate skew- t distribution to provide an estimation of the joint probability of flood events in a multi-site multi-basin approach. This constitutes the basis for the design and evaluation of flood hazard scenarios for large areas in terms of their intensity, extension and frequency, i.e. those information required by civil protection agencies to put in action mitigation strategies and by insurance companies to price the flooding risk and to evaluate portfolios. Performances of the skew- t distribution and the corresponding t copula function, introduced to represent the state of the art for multivariate simulations, are discussed with reference to the Tanaro Basin, North-western Italy. To enhance the characteristics of the correlation structure, three nested and non-nested gauging stations are selected with contributing areas from 1500 to 8000 km 2. A dataset of 76 trivariate flood events is extracted from a mean daily discharges database available for the time period from January 1995 to December 2003. Applications include the generation of multivariate skew- t and t copula samples and models' comparison through the principle of minimum cross-entropy, here revised for the application to multivariate samples. Copula and skew- t based scenario return period estimations are provided for the November 1994 flood event, i.e. the worst on record in the 1801-2001 period. Results are encouraging: the skew- t distribution seems able to describe the joint behavior, being close to the observations. Marginal distributions derived from the skew- t multivariate fit are comparable to the observed ones, and the model is also able to describe the tail behavior.

Ghizzoni, Tatiana; Roth, Giorgio; Rudari, Roberto

2010-10-01

236

Foundation Depth for Bridge Piers  

NASA Astrophysics Data System (ADS)

The safety of bridge piers built in rivers having the bed is one of the prime aspects in the study of scouring process around bridge piers. The stability of bridge piers depends on the depth of foundation provided below maximum scour level. The stability analysis of bridge piers is carried based on moment of forces acting on the caisson pier when the pier slides and tilts slightly in downstream from its position. The experiments are conducted for three pier shapes on two sediment beds and for different flow conditions. The curves indicating the stability limits are compared with Lacey's recommendations which are used in present day practice in India. The analysis presented here indicates that the Lacey's recommendation for railway bridges is safe and for some cases of the road bridges depends on grip length, angle of tilt and weight of caisson.

Veerappadevaru, G.; Gangadharaiah, T.; Jagadeesh, T. R.

2013-09-01

237

EARTHQUAKE RESPONSE OF SUSPENSION BRIDGES  

Microsoft Academic Search

Suspension bridges represent critical nodes of major transportation systems. Bridge failure during strong earthquakes poses\\u000a not only a threat of fatalities but causes a substantial interruption of emergency efforts. Although wind induced vibrations\\u000a have historically been the primary concern in the design of suspension bridges, earthquake effects have also gained importance\\u000a in recent decades. This study involves ambient vibration testing

Mustafa Erdik; Nurdan Apayd?n

238

Bridging the Watershed  

NSDL National Science Digital Library

Bridging the Watershed is a partnership between Washington DC area schools and the National Park Service that uses the Potomac River and Chesapeake Bay watersheds as "learning laboratories." The Students section of this site has some great interactive activities that help students learn how to identify plants and ecosystems, determine stream health based on macroinvertebrate identification, and understand the perils of migratory fish. This is a great Web site with a broad range of information suitable to a variety of different age levels and interests, yet with enough detail to make each section stand alone.

239

West Point Bridge Design Contest  

NSDL National Science Digital Library

The second annual West Point Bridge Design Contest concluded in May 2003. Although it is uncertain whether the contest will receive funding for future competitions, its Web site has a number of educational resources for middle and high school students. The main feature is the bridge design software, which allows the user to "model, test, and optimize a steel highway bridge, based on realistic specifications, constraints, and performance criteria." Completed designs can be submitted online for unofficial judging. The book, Designing and Building File-Folder Bridges, can also be freely downloaded. This site is also reviewed in the July 4, 2003 NSDL MET Report.

2003-01-01

240

West Point Bridge Design Contest  

NSDL National Science Digital Library

The second annual West Point Bridge Design Contest concluded in May 2003. Although it is uncertain whether the contest will receive funding for future competitions, its Web site has a number of educational resources for middle and high school students. The main feature is the bridge design software, which allows the user to "model, test, and optimize a steel highway bridge, based on realistic specifications, constraints, and performance criteria." Completed designs can be submitted online for unofficial judging. The book, Designing and Building File-Folder Bridges, can also be freely downloaded. [CL

241

47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.  

Code of Federal Regulations, 2013 CFR

...Telecommunication 5 2013-10-01 2013-10-01 false Bridge-to-bridge radiotelephone installation. 80.1007 Section...SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge Act § 80.1007...

2013-10-01

242

47 CFR 80.331 - Bridge-to-bridge communication procedure.  

Code of Federal Regulations, 2013 CFR

...Telecommunication 5 2013-10-01 2013-10-01 false Bridge-to-bridge communication procedure. 80.331 Section 80...Alarm, Urgency and Safety Procedures § 80.331 Bridge-to-bridge communication procedure. (a)...

2013-10-01

243

75 FR 62181 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation  

Federal Register 2010, 2011, 2012, 2013

...Annual Materials Report on New Bridge Construction and Bridge Rehabilitation AGENCY...Federal Register a report describing construction materials used in new Federal-aid bridge construction and bridge rehabilitation...

2010-10-07

244

77 FR 53251 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation  

Federal Register 2010, 2011, 2012, 2013

...Annual Materials Report on New Bridge Construction and Bridge Rehabilitation AGENCY...Federal Register a report describing construction materials used in new Federal-aid bridge construction and bridge rehabilitation...

2012-08-31

245

76 FR 55160 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation  

Federal Register 2010, 2011, 2012, 2013

...Annual Materials Report on New Bridge Construction and Bridge Rehabilitation AGENCY...Federal Register a report describing construction materials used in new Federal-aid bridge construction and bridge rehabilitation...

2011-09-06

246

Extended bridge algorithms for large networks  

Microsoft Academic Search

A network bridge is a device that operates at the ISO data link level and routes packets across extended networks, commonly composed of multiple local area networks (LANs) and bridges. A set of algorithms that greatly extends the application of the network bridge is presented. This multitree bridge algorithm allows networks of arbitrary topology and capacity to use bridge routing.

W. D. Sincoskie; C. J. Cotton

1988-01-01

247

Unilateral incompatibility as a major cause of skewed segregation in the cross between Lycopersicon esculentum and L. pennellii  

Microsoft Academic Search

Skewed segregations are frequent events in segregating populations derived from different interspecific crosses in tomato. To determine a basis for skewed segregations in the progeny of the cross between Lycopersicon esculentum and L. pennellii, monogenic segregations of 16 isozyme loci were analyzed in an F2 and two backcross populations of this cross. In the F2, 9 loci mapping to chromosomes

M. R. Foolad

1996-01-01

248

3. HONEYWELL STREET BRIDGE AND ELEVATED SUBWAY BRIDGE CROSSING SUNNYSIDE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. HONEYWELL STREET BRIDGE AND ELEVATED SUBWAY BRIDGE CROSSING SUNNYSIDE YARDS. LONG ISLAND CITY, QUEENS CO., NY. Sec. 1411, MP 3.55. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York, New York County, NY

249

5. North side of throughtruss bridge over railroad tracks (bridge ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. North side of through-truss bridge over railroad tracks (bridge #U182512605). View to southwest. - South Omaha Union Stock Yards, "O" Street Viaduct, "O" Street Spanning Hog Pens; South Omaha Terminal Railway Company Tracks & Union Pacific Railroad Tracks, Omaha, Douglas County, NE

250

Association for Bridge Construction and Design: Bridge Design Tips  

NSDL National Science Digital Library

The Association for Bridge Construction and Design was formed in response to "the bridge crisis" which leaves "only an extremely small percentage of bridges throughout the nation" receiving the attention they need. The goal of the Association is to educate bridge designers, constructors, federal, state, and local officials, as well as the general public in the vital role of safe bridges in our society; to improve the science of bridge design, construction and reconstruction through a professional forum; to provide technical information and assistance; and to educate and encourage public and private authorities to use new and improved techniques for testing and reconstruction. This section of the website provides a basic overview of bridge construction along with related drawings and pictures. By reading through the text and following the links, visitors are taken to a section that discusses ways to calculate the forces in your trusses and then use Java program to design trusses. Links to related articles and websites are available for further reading on the subject of bridge design. Although the website has not been updated recently, the resources are still relevant.

251

25. White Plains Road Bridge in foreground; Unionport Road Bridge ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

25. White Plains Road Bridge in foreground; Unionport Road Bridge in background. Van Nest, Bronx Co., NY. Sec. 4207, MP 12.75./78. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York, New York County, NY

252

Cogging torque reduction of flux-switching permanent magnet machines without skewing  

Microsoft Academic Search

The flux-switching permanent magnet (FSPM) machine exhibits competitive torque capability and power density due to the high flux density. As a penalty, the cogging torque is relative large, resulting in unfavorable torque pulsation. Due to the simple and robust rotor construction, additional dummy slots are adopted to reduce the cogging torque without skewing magnets or teeth. The optimal dimensions of

Wei Hua; Ming Cheng

2008-01-01

253

A computer program to construct distributions with specific degrees of skew and kurtosis  

Microsoft Academic Search

Much has been written about the importance of measures of skew and kurtosis in research and in research reporting (e.g., Hopkins and Weeks 1990). Recent books on hypothesis testing using computer intensive methods (Noreen 1989) and computer simulations (Whicker and Sigelman 1991) describe methods for testing hypotheses from distributions with known parameters, but do not provide computer code to build

Ken Stange; Robert Saltstone

1992-01-01

254

Riemannian Manifold in Which the Skew-Symmetric Curvature Operator has Pointwise Constant Eigenvalues  

Microsoft Academic Search

We study manifolds where the natural skew-symmetric curvature operator has pointwise constant eigenvalues. We give a local classification (up to isometry) of such manifolds in dimension 4. In dimension 3, we describe such manifolds up to a classification of three - dimensional Riemannian manifolds with principal Ricci curvatures r1 = r2 = 0, r3- arbitrary. We give examples of such

Stefan Ivanov; Irina Petrova

1998-01-01

255

Bayesian analysis of nonlinear mixed-effects mixture models for longitudinal data with heterogeneity and skewness.  

PubMed

It is a common practice to analyze complex longitudinal data using nonlinear mixed-effects (NLME) models with normality assumption. The NLME models with normal distributions provide the most popular framework for modeling continuous longitudinal outcomes, assuming individuals are from a homogeneous population and relying on random-effects to accommodate inter-individual variation. However, the following two issues may standout: (i) normality assumption for model errors may cause lack of robustness and subsequently lead to invalid inference and unreasonable estimates, particularly, if the data exhibit skewness and (ii) a homogeneous population assumption may be unrealistically obscuring important features of between-subject and within-subject variations, which may result in unreliable modeling results. There has been relatively few studies concerning longitudinal data with both heterogeneity and skewness features. In the last two decades, the skew distributions have shown beneficial in dealing with asymmetric data in various applications. In this article, our objective is to address the simultaneous impact of both features arisen from longitudinal data by developing a flexible finite mixture of NLME models with skew distributions under Bayesian framework that allows estimates of both model parameters and class membership probabilities for longitudinal data. Simulation studies are conducted to assess the performance of the proposed models and methods, and a real example from an AIDS clinical trial illustrates the methodology by modeling the viral dynamics to compare potential models with different distribution specifications; the analysis results are reported. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24623529

Lu, Xiaosun; Huang, Yangxin

2014-07-20

256

Large-Scale Age-Dependent Skewed Sex Ratio in a Sexually Dimorphic Avian Scavenger  

PubMed Central

Age-dependent skewed sex ratios have been observed in bird populations, with adult males generally outnumbering females. This trend is mainly driven by higher female mortality, sometimes associated with anthropogenic factors. Despite the large amount of work on bird sex ratios, research examining the spatial stability of adult sex ratios is extremely scarce. The Andean condor (Vultur gryphus) is the only bird of prey with strong sexual dimorphism favouring males (males are 30% heavier than females). By examining data from most of its South-American range, we show that while the juvenile sex ratio is balanced, or even female-skewed, the sex ratio becomes increasing male-skewed with age, with adult males outnumbering females by >20%, and, in some cases by four times more. This result is consistent across regions and independent of the nature of field data. Reasons for this are unknown but it can be hypothesized that the progressive disappearance of females may be associated with mortality caused by anthropogenic factors. This idea is supported by the asymmetric habitat use by the two sexes, with females scavenging in more humanized areas. Whatever the cause, male-skewed adult sex ratios imply that populations of this endangered scavenger face higher risks of extinction than previously believed.

Lambertucci, Sergio A.; Carrete, Martina; Donazar, Jose Antonio; Hiraldo, Fernando

2012-01-01

257

Parallel spinors and connections with skew-symmetric torsion in string theory  

Microsoft Academic Search

We describe all almost contact metric, almost hermitian and $G_2$-structures admitting a connection with totally skew-symmetric torsion tensor, and prove that there exists at most one such connection. We investigate its torsion form, its Ricci tensor, the Dirac operator and the $\\\

Thomas Friedrich; Stefan Ivanov

2001-01-01

258

Skew angle effects in shingled magnetic recording system with double/triple reader head array  

NASA Astrophysics Data System (ADS)

Shingled Magnetic Recording (SMR) is a scheme used to extend the life of the current perpendicular magnetic recording technology. SMR enables writing narrow tracks with a wide writer. Currently, SMR employs a single reader and will suffer inter-track interference (ITI) as the tracks become comparable in width to the reader. ITI can be mitigated by using narrower readers; however, narrower readers suffer from increased reader noise. Another approach to combat ITI is to process 2D readback and use ITI cancellation schemes to retrieve the data track. Multiple readbacks can be obtained either with a single reader and multiple revolutions or with a reader array. The former suffers from increased readback latency. In this work, we focus on the latter. When using a reader array, the skew angle poses major challenges. During writing, there is increased adjacent track erasure, and during readback the effective reader pitch varies and there is an increase in the 2D intersymbol interference caused by the rotated reader profile. In this work, we run micromagnetic simulations at different skew angles to train the grain flipping probability model, and then evaluate raw bit channel error rate performance at skew. In particular, we investigate the performance degradation caused by skewing of the 2 or 3 read head array for various read-head geometries.

Elidrissi, Moulay Rachid; Sann Chan, Kheong; Greaves, Simon; Kanai, Yasushi; Muraoka, Hiroaki

2014-05-01

259

An analytical algorithm for skew-slit imaging geometry with nonuniform attenuation correction  

SciTech Connect

The pinhole collimator is currently the collimator of choice in small animal single photon emission computed tomography (SPECT) imaging because it can provide high spatial resolution and reasonable sensitivity when the animal is placed very close to the pinhole. It is well known that if the collimator rotates around the object (e.g., a small animal) in a circular orbit to form a cone-beam imaging geometry with a planar trajectory, the acquired data are not sufficient for an exact artifact-free image reconstruction. In this paper a novel skew-slit collimator is mounted instead of the pinhole collimator in order to significantly reduce the image artifacts caused by the geometry. The skew-slit imaging geometry is a more generalized version of the pinhole imaging geometry. The multiple pinhole geometry can also be extended to the multiple-skew-slit geometry. An analytical algorithm for image reconstruction based on the tilted fan-beam inversion is developed with nonuniform attenuation compensation. Numerical simulation shows that the axial artifacts are evidently suppressed in the skew-slit images compared to the pinhole images and the attenuation correction is effective.

Huang Qiu; Zeng, Gengsheng L. [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84108 (United States); Utah Center for Advanced Imaging Research, 729 Arapeen Drive, University of Utah, Salt Lake City, UT 84108 (United States)

2006-04-15

260

Bayesian analysis for nonlinear regression model under skewed errors, with application in growth curves.  

PubMed

We have considered a Bayesian approach for the nonlinear regression model by replacing the normal distribution on the error term by some skewed distributions, which account for both skewness and heavy tails or skewness alone. The type of data considered in this paper concerns repeated measurements taken in time on a set of individuals. Such multiple observations on the same individual generally produce serially correlated outcomes. Thus, additionally, our model does allow for a correlation between observations made from the same individual. We have illustrated the procedure using a data set to study the growth curves of a clinic measurement of a group of pregnant women from an obstetrics clinic in Santiago, Chile. Parameter estimation and prediction were carried out using appropriate posterior simulation schemes based in Markov Chain Monte Carlo methods. Besides the deviance information criterion (DIC) and the conditional predictive ordinate (CPO), we suggest the use of proper scoring rules based on the posterior predictive distribution for comparing models. For our data set, all these criteria chose the skew-t model as the best model for the errors. These DIC and CPO criteria are also validated, for the model proposed here, through a simulation study. As a conclusion of this study, the DIC criterion is not trustful for this kind of complex model. PMID:19629998

De la Cruz, Rolando; Branco, Márcia D

2009-08-01

261

A document skew detection method using run-length encoding and the Hough transform  

Microsoft Academic Search

As part of the development of a document image analysis system, a method, based on the Hough transform, was devised for the detection of document skew and interline spacing-necessary parameters for the automatic segmentation of text from graphics. Because the Hough transform is computationally expensive, the amount of data within a document image is reduced through the computation of its

Stuart C. Hinds; James L. Fisher; Donald P. D'Amato

1990-01-01

262

Female control of reproductive skew in cooperatively breeding brown jays ( Cyanocorax morio )  

Microsoft Academic Search

Brown jays ( Cyanocorax morio) are long-lived, social corvids that live in large, stable, territorial groups (mean = 10 individuals). In this study, I determined the distribution of reproductive success within groups using multi-locus DNA fingerprinting. Breeding females produced virtually all (99%) of the young within their own nests. Reproduction within groups was highly skewed towards a single primary female,

Dean A. Williams

2004-01-01

263

Skewing (n +1) Tensor Indices where the Index Range is n  

ERIC Educational Resources Information Center

It is known that any totally skew quantity with (n + 1) indices, each of which ranges over n values, vanishes identically. The aim of this short note is to show that this is equivalent to the simple fact that any (n + 1) vectors in an n-dimensional vector space are linearly dependent.

Agacy, R. L.

2005-01-01

264

Progress in understanding the renormalization group skewness and kappa-epsilon models  

NASA Technical Reports Server (NTRS)

The immediate goal is to understand and validate the Yakhot-Orszag model of the velocity-derivative skewness and model equation for the rate of energy dissipation epsilon. A summary of a more detailed manuscript in preparation is presented. The purpose is to clarify some limitations of the theory by careful examination of key assumptions and approximations, and thereby to encourage its improvement.

Smith, Leslie M.; Reynolds, W. C.

1991-01-01

265

The effect of skewness and kurtosis on the robustness of linear mixed models.  

PubMed

This study analyzes the robustness of the linear mixed model (LMM) with the Kenward-Roger (KR) procedure to violations of normality and sphericity when used in split-plot designs with small sample sizes. Specifically, it explores the independent effect of skewness and kurtosis on KR robustness for the values of skewness and kurtosis coefficients that are most frequently found in psychological and educational research data. To this end, a Monte Carlo simulation study was designed, considering a split-plot design with three levels of the between-subjects grouping factor and four levels of the within-subjects factor. Robustness is assessed in terms of the probability of type I error. The results showed that (1) the robustness of the KR procedure does not differ as a function of the violation or satisfaction of the sphericity assumption when small samples are used; (2) the LMM with KR can be a good option for analyzing total sample sizes of 45 or larger when their distributions are normal, slightly or moderately skewed, and with different degrees of kurtosis violation; (3) the effect of skewness on the robustness of the LMM with KR is greater than the corresponding effect of kurtosis for common values; and (4) when data are not normal and the total sample size is 30, the procedure is not robust. Alternative analyses should be performed when the total sample size is 30. PMID:23299397

Arnau, Jaume; Bendayan, Rebecca; Blanca, María J; Bono, Roser

2013-09-01

266

Skew-varicose instability in two-dimensional generalized Swift-Hohenberg equations.  

PubMed

We apply analytical and numerical methods to study the linear stability of stripe patterns in two generalizations of the two-dimensional Swift-Hohenberg equation that include coupling to a mean flow. A projection operator is included in our models to allow exact stripe solutions. In the generalized models, stripes become unstable to the skew-varicose, oscillatory skew-varicose, and cross-roll instabilities, in addition to the usual Eckhaus and zigzag instabilities. We analytically derive stability boundaries for the skew-varicose instability in various cases, including several asymptotic limits. We also use numerical techniques to determine eigenvalues and hence stability boundaries of other instabilities. We extend our analysis to both stress-free and no-slip boundary conditions and we note a crossover from the behavior characteristic of no-slip to that of stress-free boundaries as the coupling to the mean flow increases or as the Prandtl number decreases. Close to the critical value of the bifurcation parameter, the skew-varicose instability has the same curvature as the Eckhaus instability provided the coupling to the mean flow is greater than a critical value. The region of stable stripes is completely eliminated by the cross-roll instability for large coupling to the mean flow. PMID:22060469

Weliwita, J A; Rucklidge, A M; Tobias, S M

2011-09-01

267

On the dominant vortex created by a pitched and skewed jet in crossflow  

Microsoft Academic Search

Vortex Generating Jets (VGJs) are jets that pass through a wall and into a crossflow to create a dominant streamwise vortex. The jets are produced by flow through holes in the wall that are pitched with respect to the wall and skewed with respect to the crossflow. For low jet to crossflow velocity ratios, the dominant vortex remains embedded in

Zia Ullah Khan

1999-01-01

268

Reproductive skew in female common marmosets: what can proximate mechanisms tell us about ultimate causes?  

PubMed

Common marmosets are cooperatively breeding monkeys that exhibit high reproductive skew: most subordinate females fail to reproduce, while others attempt to breed but produce very few surviving infants. An extensive dataset on the mechanisms limiting reproduction in laboratory-housed and free living subordinate females provides unique insights into the causes of reproductive skew. Non-breeding adult females undergo suppression of ovulation and inhibition of sexual behaviour; however, they receive little or no aggression or mating interference by dominants and do not exhibit behavioural or physiological signs of stress. Breeding subordinate females receive comparable amounts of aggression to non-breeding females but are able to conceive, gestate and lactate normally. In groups containing two breeding females,however, both dominant and subordinate breeders kill one another's infants. These findings suggest that preconception reproductive suppression is not imposed on subordinate females by dominants, at a proximate level, but is instead self-imposed by most subordinates, consistent with restraint models of reproductive skew. In contrast to restraint models, however, this self-suppression probably evolved not in response to the threat of eviction by dominant females but in response to the threat of infanticide. Thus,reproductive skew in this species appears to be generated predominantly by subordinate self-restraint, in a proximate sense, but ultimately by dominant control over subordinates' reproductive attempts. PMID:18945663

Saltzman, Wendy; Digby, Leslie J; Abbott, David H

2009-02-01

269

Adaptive biased-coin designs for skewing the allocation proportion in clinical trials with normal responses.  

PubMed

Response adaptive designs are used in phase III clinical trial for skewing the allocation pattern towards the better treatments. We use optimum design theory to derive adaptive designs when the responses are normally distributed. The performance of the designs is studied with respect to the loss and the proportion of allocation to different treatments. The adaptive design does not affect inference. PMID:16007571

Atkinson, A C; Biswas, A

2005-08-30

270

Using social parasitism to test reproductive skew models in a primitively eusocial wasp.  

PubMed

Remarkable variation exists in the distribution of reproduction (skew) among members of cooperatively breeding groups, both within and between species. Reproductive skew theory has provided an important framework for understanding this variation. In the primitively eusocial Hymenoptera, two models have been routinely tested: concessions models, which assume complete control of reproduction by a dominant individual, and tug-of-war models, which assume on-going competition among group members over reproduction. Current data provide little support for either model, but uncertainty about the ability of individuals to detect genetic relatedness and difficulties in identifying traits conferring competitive ability mean that the relative importance of concessions versus tug-of-war remains unresolved. Here, we suggest that the use of social parasitism to generate meaningful variation in key social variables represents a valuable opportunity to explore the mechanisms underpinning reproductive skew within the social Hymenoptera. We present a direct test of concessions and tug-of-war models in the paper wasp Polistes dominulus by exploiting pronounced changes in relatedness and power structures that occur following replacement of the dominant by a congeneric social parasite. Comparisons of skew in parasitized and unparasitized colonies are consistent with a tug-of-war over reproduction within P. dominulus groups, but provide no evidence for reproductive concessions. PMID:24990668

Green, Jonathan P; Cant, Michael A; Field, Jeremy

2014-08-22

271

WP9.06 Skew Detection and Compensation for Internet Audio Applications  

Microsoft Academic Search

Long lived audio streams, such as music broadcasts, and small differences in clock rates lead to buffer underflo w or overflo w events in receiving applications that manifest themselves as au- dible interruptions. We present a low complexity algorithm for detecting clock skew in network audio applications that function with local clocks and in the absence of a synchronization mech-

Orion Hodson; Colin Perkins; Vicky Hardman

2000-01-01

272

Heat transfer in rotating serpentine passages with trips skewed to the flow  

Microsoft Academic Search

Experiments were conducted to determine the effects of buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. The experiments were conducted with a large-scale, multipass, heat transfer model with both radially inward and outward flow. Trip strips, skewed at 45 deg to the flow direction, were machined on the leading and trailing surfaces of the radial

B. V. Johnson; J. H. Wagner; G. D. Steuber; F. C. Yeh

1994-01-01

273

On Some Confidence Intervals for Estimating the Mean of a Skewed Population  

ERIC Educational Resources Information Center

A number of methods are available in the literature to measure confidence intervals. Here, confidence intervals for estimating the population mean of a skewed distribution are considered. This note proposes two alternative confidence intervals, namely, Median t and Mad t, which are simple adjustments to the Student's t confidence interval. In…

Shi, W.; Kibria, B. M. Golam

2007-01-01

274

Skew-varicose instability in two-dimensional generalized Swift-Hohenberg equations  

NASA Astrophysics Data System (ADS)

We apply analytical and numerical methods to study the linear stability of stripe patterns in two generalizations of the two-dimensional Swift-Hohenberg equation that include coupling to a mean flow. A projection operator is included in our models to allow exact stripe solutions. In the generalized models, stripes become unstable to the skew-varicose, oscillatory skew-varicose, and cross-roll instabilities, in addition to the usual Eckhaus and zigzag instabilities. We analytically derive stability boundaries for the skew-varicose instability in various cases, including several asymptotic limits. We also use numerical techniques to determine eigenvalues and hence stability boundaries of other instabilities. We extend our analysis to both stress-free and no-slip boundary conditions and we note a crossover from the behavior characteristic of no-slip to that of stress-free boundaries as the coupling to the mean flow increases or as the Prandtl number decreases. Close to the critical value of the bifurcation parameter, the skew-varicose instability has the same curvature as the Eckhaus instability provided the coupling to the mean flow is greater than a critical value. The region of stable stripes is completely eliminated by the cross-roll instability for large coupling to the mean flow.

Weliwita, J. A.; Rucklidge, A. M.; Tobias, S. M.

2011-09-01

275

Quantifying reinforced concrete bridge deck deterioration using ground penetrating radar  

NASA Astrophysics Data System (ADS)

Bridge decks are deteriorating at an alarming rate due to corrosion of the reinforcing steel, requiring billions of dollars to repair and replace them. Furthermore, the techniques used to assess the decks don't provide enough quantitative information. In recent years, ground penetrating radar (GPR) has been used to quantify deterioration by comparing the rebar reflection amplitudes to technologies serving as ground truth, because there is not an available amplitude threshold to distinguish healthy from corroded areas using only GPR. The goal of this research is to understand the relationship between GPR and deck deterioration, and develop a model to determine deterioration quantities with GPR alone. The beginning of this research determines that not only is the relationship between GPR and rebar corrosion stronger than the relationship between GPR and delaminations, but that the two are exceptionally correlated (90.2% and 86.6%). Next, multiple bridge decks were assessed with GPR and half-cell potential (HCP). Statistical parameters like the mean and skewness were computed for the GPR amplitudes of each deck, and coupled with actual corrosion quantities based on the HCP measurements to form a future bridge deck model that can be used to assess any deck with GPR alone. Finally, in order to understand exactly which component of rebar corrosion (rust, cracking or chloride) attenuates the GPR data, computational modeling was carried out to isolate each variable. The results indicate that chloride is the major contributor to the rebar reflection attenuation, and that computational modeling can be used to accurately simulate GPR attenuation due to chloride.

Martino, Nicole Marie

276

Evaluation of the Bridge Program.  

ERIC Educational Resources Information Center

This evaluation of the 1989-90 BRIDGE Project, a dropout prevention program in Hartford (Connecticut), found that grade 9 students felt a heightened sense of control over their lives after one year in the program. BRIDGE is a multifaceted program that focuses on reducing the disengagement of at-risk students facing the critical transition from…

Words + Numbers, Torrington, CT.

277

Fatigue of steel bridge infrastructure  

Microsoft Academic Search

This paper presents an overview of the development of fatigue design provisions and detailing for steel bridge structures. The historical performance of welded steel bridges in the USA is reviewed with focus on fatigue cracking at cover plate and similar attachment details, as well as distortion induced cracking at web gaps. The role of materials including modern high performance steels

J. W. Fisher; S. Roy

2011-01-01

278

The Bridge of Mandolin County  

Microsoft Academic Search

The Bridge of Mandolin County is a case designed to teach the general chemistry principles of molar mass, ions and aqueous reactions, solubility rules, and inorganic nomenclature. Through the instructor-facilitated class discussion, students consider the options before the Mandolin Town Council regarding deicing the newly constructed bridge connecting Mandolin with a large nearby city. The students must decipher contradictory claims

Juliette M. Lantz; Jenny E. Feindt; Eric P. B. Lewellyn; Mary M. Walczak

1999-01-01

279

Seismic Isolation of Highway Bridges.  

National Technical Information Service (NTIS)

More than 200 bridges have been designed or retrofitted in the United States using seismic isolation in the last 20 years, and more than a thousand bridges around the world now use this cost- effective technique for seismic protection. Intended to supplem...

2006-01-01

280

Life Cycle Cost of Bridges.  

National Technical Information Service (NTIS)

This is a continuation of the 2004 project to use historical cost data from a variety of geographically distributed bridges of different structural designs to (a) formulate a cost model for bridge life cycle cost, (b) assess the impact of deferred mainten...

R. Krizek

2009-01-01

281

Trigenomic Bridges for Brassica Improvement  

Microsoft Academic Search

We introduce and review Brassica crop improvement via trigenomic bridges. Six economically important Brassica species share three major genomes (A, B, and C), which are arranged in diploid (AA, BB, and CC) and allotetraploid (AABB, AACC, and BBCC) species in the classical triangle of U. Trigenomic bridges are Brassica interspecific hybrid plants that contain the three genomes in various combinations,

Sheng Chen; Matthew N. Nelson; Anne-Marie Chèvre; Eric Jenczewski; Zaiyun Li; Annaliese S. Mason; Jinling Meng; Julie A. Plummer; Aneeta Pradhan; Kadambot H. M. Siddique; Rod J. Snowdon; Guijun Yan; Weijun Zhou; Wallace A. Cowling

2011-01-01

282

Prioritization of Bridges for Seismic Retrofitting.  

National Technical Information Service (NTIS)

This report presents a prioritization method developed for seismic retrofitting of bridges. The method is used to identify bridges that are in most need of retrofitting and rank order these bridges based on the vulnerability and importance criteria. Vulne...

N. Basoez A. S. Kiremidjian

1995-01-01

283

Developing Deterioration Models for Nebraska Bridges.  

National Technical Information Service (NTIS)

Nebraska Bridge Management System (NBMS) was developed in 1999 to assist in optimizing budget allocation for the maintenance, rehabilitation and replacement needs of highway bridges. This requires the prediction of bridge deterioration to calculate life-c...

A. Hatami G. Morcous

2011-01-01

284

33 CFR 115.40 - Bridge repairs.  

Code of Federal Regulations, 2013 CFR

...Waters 1 2013-07-01 2013-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation...Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE...

2013-07-01

285

Using purine skews to predict genes in AT-rich poxviruses  

PubMed Central

Background Clusters or runs of purines on the mRNA synonymous strand have been found in many different organisms including orthopoxviruses. The purine bias that is exhibited by these clusters can be observed using a purine skew and in the case of poxviruses, these skews can be used to help determine the coding strand of a particular segment of the genome. Combined with previous findings that minor ORFs have lower than average aspartate and glutamate composition and higher than average serine composition, purine content can be used to predict the likelihood of a poxvirus ORF being a "real gene". Results Using purine skews and a "quality" measure designed to incorporate previous findings about minor ORFs, we have found that in our training case (vaccinia virus strain Copenhagen), 59 of 65 minor (small and unlikely to be a real genes) ORFs were correctly classified as being minor. Of the 201 major (large and likely to be real genes) vaccinia ORFs, 192 were correctly classified as being major. Performing a similar analysis with the entomopoxvirus amsacta moorei (AMEV), it was found that 4 major ORFs were incorrectly classified as minor and 9 minor ORFs were incorrectly classified as major. The purine abundance observed for major ORFs in vaccinia virus was found to stem primarily from the first codon position with both the second and third codon positions containing roughly equal amounts of purines and pyrimidines. Conclusion Purine skews and a "quality" measure can be used to predict functional ORFs and purine skews in particular can be used to determine which of two overlapping ORFs is most likely to be the real gene if neither of the two ORFs has orthologs in other poxviruses.

Da Silva, Melissa; Upton, Chris

2005-01-01

286

Reproductive skew and relatedness in social groups of European badgers, Meles meles.  

PubMed

Reproductive skew is a measure of the proportion of individuals of each sex that breed in a group and is a valuable measure for understanding the evolution and maintenance of sociality. Here, we provide the first quantification of reproductive skew within social groups of European badgers Meles meles, throughout an 18-year study in a high-density population. We used 22 microsatellite loci to analyse within-group relatedness and demonstrated that badger groups contained relatives. The average within-group relatedness was high (R = 0.20) and approximately one-third of within-group dyads were more likely to represent first-order kin than unrelated pairs. Adult females within groups had higher pairwise relatedness than adult males, due to the high frequency of extra-group paternities, rather than permanent physical dispersal. Spatial clustering of relatives occurred among neighbouring groups, which we suggest was due to the majority of extra-group paternities being attributable to neighbouring males. Reproductive skew was found among within-group candidate fathers (B = 0.26) and candidate mothers (B = 0.07), but not among breeding individuals; our power to detect skew in the latter was low. We use these results to evaluate reproductive skew models. Although badger society best fits the assumptions of the incomplete-control models, our results were not consistent with their predictions. We suggest that this may be due to female control of paternity, female-female reproductive suppression occurring only in years with high food availability resulting in competition over access to breeding sites, extra-group paternity masking the benefits of natal philopatry, and/or the inconsistent occurrence of hierarchies that are linear when established. PMID:18371017

Dugdale, Hannah L; Macdonald, David W; Pope, Lisa C; Johnson, Paul J; Burke, Terry

2008-04-01

287

Bridges to Structure  

NSDL National Science Digital Library

This project's goals are to investigate structural components at a variety of levels: molecularly, cellularlly (histologically),phylogenetically, organismally, etc. Traditionally the stuctural classes at many institutions have used primarily dissection and histology for comparison of different vertebrate classes. In this project, we began to develop exercises at the molecular level using gemonmic and proteomic information to form phylogenetic trees, started a chart of materials available at NCBI for use in comparison (phylogentically and visually) of characteristic proteins from specific organ systems, and initiated thinking about a project to start a pictorial archive of dissection activities and histological meassurements. With the signifcant movement to integrate more material within biology and other areas of science and mathematics, building bridges (exercises) amongst a number of levels seems relevant. In addition, adding more open-ended projects with greater manipulation of data and mathematical manipulation in these courses is very desirable.

Peter Woodruff (Champlain-St. Lambert College;); Joyce Cadawallader (Saint-Mary-of-the-Woods College;)

2004-06-12

288

Semiconductor Bridge Cable Test  

SciTech Connect

The semiconductor bridge (SCB) is an electroexplosive device used to initiate detonators. A C cable is commonly used to connect the SCB to a firing set. A series of tests were performed to identify smaller, lighter cables for firing single and multiple SCBs. This report provides a description of these tests and their results. It was demonstrated that lower threshold voltages and faster firing times can be achieved by increasing the wire size, which reduces ohmic losses. The RF 100 appears to be a reasonable substitute for C cable when firing single SCBs. This would reduce the cable volume by 68% and the weight by 67% while increasing the threshold voltage by only 22%. In general, RG 58 outperforms twisted pair when firing multiple SCBs in parallel. The RG 58's superior performance is attributed to its larger conductor size.

KING, TONY L.

2002-01-01

289

A bridge between cultures  

NASA Astrophysics Data System (ADS)

Journalists who report on scientific discoveries and the scientists who make them are, in many cases, separated by a Grand Canyon-sized gap. A recent U.S. survey revealed that journalists believe that scientists' jargon prevents effective communication. Scientists polled in the same survey, conducted by Today Show host Jim Hartz and NASA scientist Rick Chappell, said that journalists need to do a better job of verifying facts and interpreting scientific results.Panelists representing the scientific and media communities will discuss ways to bridge that gap during the “Science and the Media” episode of Freedom Speaks, to be aired by Public Broadcasting Stations in May and June (check your local listings).

Friebele, Elaine

290

Stanford: The Bridge Project  

NSDL National Science Digital Library

Stanford University's Bridge Project: Strengthening K-16 Transition Policies emphasizes that "reforms affecting K-12 and higher education must occur across systems in order to achieve the desired outcomes." Their approach is to improve opportunities for all students to enter and succeed in higher education by strengthening the alignment between higher education admissions-related requirements and K-12 curriculum frameworks, standards, and assessments. They conduct research that is meant to inform educational institutions and federal, state, and local agencies through descriptive analysis of the policies, identification of "disjunctures that exist in the current policy environment," and recommendations for improving the current system. Details about this program as well as their policy reports and briefs are available from their website.

291

Cascaded resonant bridge converters  

NASA Technical Reports Server (NTRS)

A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

Stuart, Thomas A. (Inventor)

1989-01-01

292

Construction Technologies: Construct the Strongest Bridge  

NSDL National Science Digital Library

Learners work in pairs to create three simple types of bridges, a beam bridge, an arch bridge, and a suspension bridge. They will observe how the bridges work under load and discover why engineers use different types of bridges for different places. Learners are introduced to the parts needed to build a bridge, and what they are for. Resource contains detailed diagrams and photos to assist in bridge building. Investigating questions allow learners to discuss the activity and apply their understanding to their world. Activity time can be split across multiple meetings.

Trahan-Liptak, Joy

2005-01-01

293

Nanoparticle bridge DNA biosensor  

NASA Astrophysics Data System (ADS)

A new DNA sensing method is demonstrated in which DNA hybridization events lead to the formation of nanoparticle satellites that bridge two electrodes and are detected electrically. The hybridization events are exclusively carried out only on specific locations, the surfaces of C-ssDNA modified 50 nm GNPs. The uniqueness of this work is that only a small number of T-ccDNA molecules (<10) is required to form the nanoparticle satellites, allowing ultra-sensitive DNA sensing. The principle of this new DNA sensing technique has been demonstrated using target DNA and three-base-pair-mismatched DNA in 20nM concentrations. Three single-stranded DNA (ssDNA) system is used in our experiment which includes Capture-ssDNA (C-ssDNA), Target-ssDNA (T-ssDNA) and Probe-ssDNA (P-ssDNA). Both C-ssDNA and P-ssDNA are modified by a thiol group and can hybridize with different portions of T-ssDNA. T-ssDNA requires no modification in three ssDNA system, which is beneficial in many applications. C-ssDNA modified 50nm gold nanoparticle (C-50au) and P-ssDNA modified 30nm gold nanoparticle (P-30au) are prepared through the reaction of thiol-gold chemical bonding between thiolated ssDNA and gold nanoparticle (GNP) (C-ssDNA with 50nm GNP, P-ssDNA with 30nm GNP). We controllably place the C-50au only on the SiO2 band surface (˜ 90nm width) between two gold electrodes (source and drain electrodes) by forming positively- and negatively-charged self-assembled monolayers (SAMs) on SiO2 and gold surface, respectively. DNA modified GNP is negatively charged due to ionization of phosphate group on DNA back bone. C-50au therefore is negatively charged and can only be attracted toward SiO2 area (repelled by negatively charged gold electrode surface). The amine group of positively-charged SAMs on SiO2 surface is then passivated by converting to non-polar methyl functional group after C-50au placement. P-30au is first hybridized with T-ssDNA in the solution phase (T-P- 30au formed) and is introduced into DNA detection device in which C-50au are immobilized on ˜90nm width SiO2 band (between two gold electrodes). The passivation step ensures every TP-30au are attached only to C-50au through hybridization (T-P-30au will not be attracted toward SiO2 surface or gold electrodes). GNP bridges are formed across the electrodes and provide an electrical path between two gold electrodes. We ensure that every T-P-30au only hybridizes on the surface of C-50au by (1) accurately controlling C-50au placement between two gold electrodes, (2) passivating positively-charged SAMs on SiO2 surface after C-50au immobilization. When T-P-30au hybridize with C-50au on ˜90nm wide SiO 2 surface, GNP bridges form and provide an electrical path between two gold electrodes even with only a few hybridization events. Experimental results show that even a few GNP bridges formed on SiO2 band can provide a significant conductance change from an open circuit to a conductive circuit (current = 0.5 uA at voltage = 0.1 V with four GNP bridge). We also used 3-base-pair-mismatched ssDNA (3mm-ssDNA) as a control experiment, which always resulted in an open circuit (no GNP bridge formed). Our detection device is compatible with current CMOS fabrication technology and can be manufactured on a wafer scale. The direct electrical output of this DNA detection technique provides a promising basis for high-throughput screening (can be fabricated on a wafer scale) with no expensive equipment required.

Huang, Hong-Wen

294

Chesapeake Bay Bridge-Tunnel  

NSDL National Science Digital Library

The Chesapeake Bay Bridge-Tunnel is a 20 mile long series of bridges and tunnels that connect Virginia Beach/Norfolk to Virginia's Eastern Shore. The project is an engineering marvel; besides supporting vehicular traffic, the tunnels allow sea-going vessels passage into and out of the bay. A great deal of information is given on the project's home page, including a map of the surrounding area, historical perspectives, interesting facts, tourist attractions, and frequently asked questions. There are also a few pictures scattered throughout the site that show the enormity of the bridge-tunnel.

2002-01-01

295

Singly bridged calix  

PubMed

Crowned calix[8]arenes are obtained by direct alkylation of p-tert-butylcalix[8]arene (1) with poly(ethylene glycol) ditosylates in the presence of various bases. K2CO3 promotes the preferential formation of 1,3-calix[8]crowns. Cs2CO3 mainly gives the 1,5-isomers, which are selectively obtained in high yields when shorter chains are used (1,5-crown-2, 88%; 1,5-crown-3, 78%). NaH affords the 1,4-isomers in yields up to 46%, often as the sole crown derivative, besides unreacted 1. 1,2-Calix[8]crowns are also obtained in appreciable amount in some instances. The observed regioselectivity is rationalized in terms of preferential formation of specific anions in dependence of the base strength. Dynamic NMR and modeling studies prove that the polyether chain, depending on its bridging mode, may significantly reduce the available space for the through the annulus passages leading to derivatives conformationally blocked (on the NMR time scale). PMID:10993339

Geraci; Piattelli; Chessari; Neri

2000-08-25

296

An Alternative to Bridge Painting.  

National Technical Information Service (NTIS)

A novel approach to the protection of the structural steelwork of composite bridges is proposed by physically changing the environment to which the steelwork is exposed. Clean steel does not corrode at relative humidities up to 99 percent if environmental...

R. R. Bishop M. A. Winnett

1980-01-01

297

Semiconductor bridge ignited gas generator.  

National Technical Information Service (NTIS)

Compact, lightweight, self-contained gas generator systems are required for a variety of inflation or deployment applications. We designed a generic gas generator employing a semiconductor bridge, SCB, igniter to evaluate the characteristics of the black ...

M. C. Grubelich R. W. Bickes

1992-01-01

298

Resistance Bridge Transducer Conditioning Circuit.  

National Technical Information Service (NTIS)

The patent application relates to a conditioning circuit for a resistance bridge transducer that includes output signal amplification, a voltage regulated DC power source for transducer excitation and a calibration select circuit for selectively inserting...

D. J. Ray

1976-01-01

299

Skew projection of echo-detected EPR spectra for increased sensitivity and resolution.  

PubMed

The measurement of EPR spectra during pulsed EPR experiments is commonly accomplished by recording the integral of the electron spin echo as the applied magnetic field is stepped through the spectrum. This approach to echo-detected EPR spectral measurement (ED-EPR) limits sensitivity and spectral resolution and can cause gross distortions in the resulting spectra because some of the information present in the electron spin echo is discarded in such measurements. However, Fourier transformation of echo shapes measured at a series of magnetic field values followed by skew projection onto either a magnetic field or resonance frequency axis can increase both spectral resolution and sensitivity without the need to trade one against the other. Examples of skew-projected spectra with single crystals, glasses and powders show resolution improvements as large as a factor of seven with sensitivity increases of as much as a factor of five. PMID:23644351

Bowman, Michael K; Krzyaniak, Matthew D; Cruce, Alex A; Weber, Ralph T

2013-06-01

300

Myeloid skewing in murine autoimmune arthritis occurs in hematopoietic stem and primitive progenitor cells  

PubMed Central

Skewing toward myeloid cell production is often observed in chronic inflammation and autoimmune diseases. Herein, we determined whether persistent myeloid activation and proinflammatory output occurring in pathologic conditions is at the level of hematopoietic stem and primitive progenitor cells (HSPPCs). By using a mouse arthritis model, we found that even though HSPPCs in arthritis still retained the capacity to differentiate into different lineages, they acquired enhanced in vitro and in vivo propensity in a disease-dependent manner to generate myeloid cells, the key perpetrators of tissue damage in arthritis. This myeloid skewing was cell intrinsic, as arthritic HSPPCs up-regulate myeloid-specific transcripts including S100a8. Exogenous S100a8 promoted myeloid cell output from wild-type HSPPCs, suggesting mechanistic involvement of this gene in the myeloid priming that occurs in arthritic HSPPCs. Therefore, our results indicate that in arthritic mice, HSPPCs adopt a pathologic state that favors disease persistence.

Oduro, Kwadwo A.; Liu, Fang; Tan, Qing; Kim, Chan-Kyu; Lubman, Olga; Fremont, Daved; Mills, Jason C.

2012-01-01

301

Skewing of immune cell cytokine production by mediators from adipocytes and endothelial cells.  

PubMed

Since adipose tissue is composed of adipocytes as well as other cell types including endothelial cells, this study sought to determine how mediators from adipocytes and from endothelial cells impact on immune cell production of cytokines. A minimalistic design was used in which media conditioned by adipocytes or by endothelial cells were added individually or as a mixture to normal spleen cells. Media from adipocytes or endothelial cells each stimulated spleen cell production of Th1 cytokines, Th2 cytokines, most of the measured inflammatory cytokines, and some chemokines. However, a mixture of media conditioned by adipocytes and by endothelial cells inhibited production of Th1 cytokines and skewed reactivity toward a Th2 and inflammatory phenotype. Adiponectin, but not leptin, was shown to contribute to the skewing of immune responsiveness to endothelial cell-derived mediators. PMID:24719786

Vielma, Silvana A; Klein, Richard L; Levingston, Corinne A; Young, M Rita I

2014-04-01

302

Second-order matter density perturbations and skewness in scalar-tensor modified gravity models  

SciTech Connect

We study second-order cosmological perturbations in scalar-tensor models of dark energy that satisfy local gravity constraints, including f(R) gravity. We derive equations for matter fluctuations under a sub-horizon approximation and clarify conditions under which first-order perturbations in the scalar field can be neglected relative to second-order matter and velocity perturbations. We also compute the skewness of the matter density distribution and find that the difference from the {Lambda}CDM (CDM: cold dark matter) model is less than a few per cent even if the growth rate of first-order perturbations is significantly different from that in the {Lambda}CDM model. This shows that the skewness provides a model-independent test for the picture of gravitational instability from Gaussian initial perturbations including scalar-tensor modified gravity models.

Tatekawa, Takayuki [Department of Computer Science, Kogakuin University, 1-24-2 Nishi-shinjuku, Shinjuku, Tokyo 163-8677 (Japan)] [Department of Computer Science, Kogakuin University, 1-24-2 Nishi-shinjuku, Shinjuku, Tokyo 163-8677 (Japan); Tsujikawa, Shinji, E-mail: tatekawa@cpd.kogakuin.ac.jp, E-mail: shinji@rs.kagu.tus.ac.jp [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)] [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

2008-09-15

303

Washed Out Bridge, Snake Creek Near Whitesburg  

USGS Multimedia Gallery

Tributary to Snake Creek, near Whitesburg, Georgia, showing a washed out bridge. When bridges such as this one collapse during a flood, it is rarely the pressure of the rushing water against the bridge that causes the bridge to fail. Rather, the rushing water erodes the ground underneath and surroun...

2009-10-01

304

Geology Fieldnotes: Natural Bridges National Monument, Utah  

NSDL National Science Digital Library

This site describes how natural bridges form in crossbedded sandstone, the three stages of bridge maturity, and the differences between bridges and arches. Also included are photographs, park maps, visitor information, and details on the discovery of the Owachomo, Sipapu, and Kachina Bridges.

305

Feedback bridging fault detection using current monitoring  

Microsoft Academic Search

Feedback bridging faults in CMOS circuits are difficult to detect by monitoring logic values. The authors study the possibility of detecting feedback bridging faults by using current monitoring. It is shown that by monitoring current, the feedback bridging faults that cause a metastable state can be detected. Using the same method, the feedback bridging faults can also be detected that

D. Lu; C. Q. Tong

1992-01-01

306

User-friendly Indices for Bridge Management  

Microsoft Academic Search

The Road Bureau of the Ministry of Land, Infrastructure and Transport (MLIT) is promoting scientific bridge management to effectively preserve the enormous number of bridges in Japan. In the process of strategic bridge management, it is important to explain the needs for preventive investment or management level of highway bridges using proper indices. The National Institute for Land and Infrastructure

Takashi Tamakoshi; Keita Nakasu; Ryoichi Watanabe

307

Earthquake Response of Suspension Bridges  

NASA Astrophysics Data System (ADS)

Suspension bridges represent critical nodes of major transportation systems. Bridge failure during strong earthquakes poses not only a threat of fatalities but causes a substantial interruption of emergency efforts. Although wind induced vibrations have historically been the primary concern in the design of suspension bridges, earthquake effects have also gained importance in recent decades. This study involves ambient vibration testing and sophisticated three-dimensional dynamic finite element analysis and earthquake performance assessment of Fatih Sultan Mehmet and suspension Bo?aziçi bridges in Istanbul under earthquake excitation. Nonlinear time history analysis of 3D finite-element models of Fatih Sultan Mehmet and Bo?aziçi suspension bridges included initial stresses in the cables, suspenders, and towers in equilibrium under dead load conditions. Multi-support scenario earthquake excitation was applied to the structure. Suspension bridges are complex 3-D structures that can exhibit a large number of closely spaced coupled modes of vibration. The large number of closely spaced modes, spatially different ground motion characteristics, and the potential for nonlinear behaviour complicate the seismic response of suspension bridges. Spatial variation of ground motion exhibits itself with different ground motions at supports due to the wave passage, incoherence and local site effects. The source of nonlinear behaviour is due to geometric nonlinearity and the presence of cables that can only carry tensile forces. The natural frequencies of vibration and the corresponding mode shapes in their dead load and live load configurations are determined. Displacement time histories and stresses at critical points of the bridges are computed and their earthquake performance under the action of scenario earthquake are estimated.

Erdik, Mustafa; Apayd?n, Nurdan

308

Skewness in CMB temperature fluctuations from curved cosmic (super-)strings  

Microsoft Academic Search

We compute the one-point probability distribution function of small-angle cosmic microwave background temperature fluctuations due to curved cosmic (super-)strings with a simple model of string network by performing Monte Carlo simulations. Taking into account of the correlation between the curvature and the velocity of string segments, there appear non-Gaussian features, specifically non-Gaussian tails and a skewness, in the one-point pdf.

Daisuke Yamauchi; Yuuiti Sendouda; Chul-Moon Yoo; Keitaro Takahashi; Atsushi Naruko; Misao Sasaki

2010-01-01

309

Skewness and Kurtosis in S&P 500 Index Returns Implied by Option Prices  

Microsoft Academic Search

The Black-Scholes (1973) model frequently misprices deep-in-the-money and deep-out-of-the-money options. Practitioners popularly refer to these strike price biases as volatility smiles. In this paper we examine a method to extend the Black-Scholes model to account for biases induced by nonnormal skewness and kurtosis in stock return distributions. The method adapts a Gram-Charlier series expansion of the normal density function to

Charles J. Corrado; Tie Su

1996-01-01

310

Schäffer spaces and uniform exponential stability of linear skew-product semiflows  

NASA Astrophysics Data System (ADS)

We study the exponential stability of linear skew-product semiflows on locally compact metric space with Banach fibers. Our main tool is the admissibility of a pair of the so-called Schäffer spaces. This characterization is a very general one, it includes as particular cases many interesting situations among them we can mention some results due to Clark, Datko, Latushkin, van Minh, Montgomery-Smith, Randolph, Räbiger, Schnaubelt.

Preda, Petre; Pogan, Alin; Preda, Ciprian

311

Skew of Mononucleotide Frequencies, Relative Abundance of Dinucleotides, and DNA Strand Asymmetry  

Microsoft Academic Search

.   Based on 152 mitochondrial genomes and 36 bacterial chromosomes that have been completely sequenced, as well as three long\\u000a contigs for human chromosomes 6, 21, and 22, we examined skews of mononucleotide frequencies and the relative abundance of\\u000a dinucleotides in one DNA strand. Each group of these genomes has its own characteristics. Regarding mitochondrial genomes,\\u000a both CpG and GpT

Chiharu Shioiri; Naoyuki Takahata

2001-01-01

312

Design and testing of a redundant skewed inertial sensor complex for integrated navigation and flight control  

NASA Technical Reports Server (NTRS)

Requirements for a redundant strapdown inertial sensor complex applied to V/STOL aircraft as developed by NASA are presented. Flight test data of a redundant, skewed axis strapdown inertial system are given, demonstrating the feasibility of the primary design aspects. This data consisted of parity equation responses through various flight conditions, showing residual noise levels on redundant gyro and accelerometer comparisons as a measure of minimum failure-level detectability, plus failure isolation and navigation performance through several simulated instrument failures.

Ebner, R. E.; Howell, W. E.

1979-01-01

313

Skew-Free Optical Interconnections Using Fiber Image Guides for Petabit-per-Second Computer Networks  

Microsoft Academic Search

Parallel interconnections using vertical-cavity surface-emitting laser (VCSEL)-based fiber image guides (FIGs) have been proposed. The FIGs consist of many individual optical fibers. The core in each optical fiber is small, and thus, modal distortions may be small. All optical fibers in an array are fabricated under the same conditions. Characteristics for each optical fiber are almost uniform, and skew in

Shigeru Kawai; Yao Li; Ting Wang

1998-01-01

314

A modified Waldron test based on sliding skewness for determining asymmetric cycle in a turbidite section  

Microsoft Academic Search

The non-parametric ‘sign-of-difference’ Waldron test, conventionally used for identifying asymmetric cyclicity (thinning-or\\u000a thickening-up) in turbidite successions, often fails to offer convincing results either when bed thickness distribution is\\u000a lognormal or where positive and negative cycles are present in equal abundance. A modified Waldron test based on sliding skewness\\u000a method (taking a number of bed thickness at a time) is proposed

Basab Mukhopadhyay; Partha Pratim Chakraborty; Tapan Majumder

2004-01-01

315

Permanent Magnet Skew Quadrupoles for the Low Emittance LER Lattice of PEP-II  

SciTech Connect

The vertical emittance of the low energy ring (LER) in the PEP-II B-Factory was reduced by using skew quadrupoles consisting of permanent magnet material. The advantages over electric quadrupoles or rotating existing normal quadrupoles are discussed. To assure a high field quality, a Biot-Savart calculation was used to cancel the natural 12-pole component by using different size poles over a few layers. A magnetic measurement confirmed the high quality of the magnets. After installation and adjusting the original electric 12 skew and 16 normal quadrupoles the emittance contribution from the region close to the interaction point, which was the biggest part in the original design, was considerably reduced. To strengthen the vertical behavior of the LER beam, a low emittance lattice was developed. It lowered the original vertical design emittance from 0.54 nm-rad to 0.034 nm-rad. In order to achieve this, additional skew quadrupoles were required to bring the coupling correction out of the arcs and closer to the detector solenoid in the straight (Fig. 1). It is important, together with low vertical dispersion, that the low vertical emittance is not coupled into the horizontal, which is what we get if the coupling correction continues into the arcs. Further details of the lattice work is described in another paper; here we concentrate on the development of the permanent skew (PSK) quadrupole solution. Besides the permanent magnets there are two other possibilities, using electric magnets or rotating normal quadrupoles. Electric magnets would have required much more additional equipment like magnets stands, power supply, and new vacuum chamber sections. Rotating existing quadrupoles was also not feasible since they are mostly mounted together with a bending magnet on the same support girder.

Decker, F.-J.; Anderson, S.; Kharakh, D.; Sullivan, M.; /SLAC

2011-07-05

316

Effect of phase response curve skew on synchronization with and without conduction delays.  

PubMed

A central problem in cortical processing including sensory binding and attentional gating is how neurons can synchronize their responses with zero or near-zero time lag. For a spontaneously firing neuron, an input from another neuron can delay or advance the next spike by different amounts depending upon the timing of the input relative to the previous spike. This information constitutes the phase response curve (PRC). We present a simple graphical method for determining the effect of PRC shape on synchronization tendencies and illustrate it using type 1 PRCs, which consist entirely of advances (delays) in response to excitation (inhibition). We obtained the following generic solutions for type 1 PRCs, which include the pulse-coupled leaky integrate and fire model. For pairs with mutual excitation, exact synchrony can be stable for strong coupling because of the stabilizing effect of the causal limit region of the PRC in which an input triggers a spike immediately upon arrival. However, synchrony is unstable for short delays, because delayed inputs arrive during a refractory period and cannot trigger an immediate spike. Right skew destabilizes antiphase and enables modes with time lags that grow as the conduction delay is increased. Therefore, right skew favors near synchrony at short conduction delays and a gradual transition between synchrony and antiphase for pairs coupled by mutual excitation. For pairs with mutual inhibition, zero time lag synchrony is stable for conduction delays ranging from zero to a substantial fraction of the period for pairs. However, for right skew there is a preferred antiphase mode at short delays. In contrast to mutual excitation, left skew destabilizes antiphase for mutual inhibition so that synchrony dominates at short delays as well. These pairwise synchronization tendencies constrain the synchronization properties of neurons embedded in larger networks. PMID:24376399

Canavier, Carmen C; Wang, Shuoguo; Chandrasekaran, Lakshmi

2013-01-01

317

3-D electro-magnetic analyses of a cage induction motor with rotor skew  

Microsoft Academic Search

The paper studied the performance characteristics of a three-phase cage induction motor using a 3D finite element technique. Especially, the effects of rotor skew and the rotor end-rings and the distribution of the electromagnetic field toward the axial direction, which have not been able to be analyzed accurately by 2D analysis, were investigated. Since the 3D analysis enabled the analysis

H. Kometani; S. Sakabe; K. Nakanishi

1996-01-01

318

Experimental observation of a skewed X-type spatiotemporal correlation of ultrabroadband twin beams.  

PubMed

This work presents the experimental observation of the nonfactorable near-field spatiotemporal correlation of ultrabroadband twin beams generated by parametric down-conversion, in an interferometric-type experiment using sum frequency generation, where both the temporal and the spatial degrees of freedom of parametric down-conversion light are controlled with high resolution. The revealed correlation is skewed in space-time in accordance with the X structure predicted by the theory. PMID:23368318

Jedrkiewicz, O; Gatti, A; Brambilla, E; Di Trapani, P

2012-12-14

319

Sacrificial bridges for MEMS fabrication  

NASA Astrophysics Data System (ADS)

This study discusses sacrificial bridges that are used to release MEMS devices. Before being released, sacrificial bridges connect all the component structures into an integral structure. Solder bump bonding is used to mount the MEMS chip on another chip or a printed circuit board (PCB) and to maintain the alignment among all component structures after removal of the sacrificial bridges. Two types of sacrificial bridges were designed, analyzed and fabricated. The fabrication process—which used low resistivity single crystal silicon (SCS) wafers as the device material—was developed to implement the sacrificial bridges. Novel SCS through silicon vias (TSVs), which interconnect stacked chips, was made using the same process. An electrostatic comb drive actuator was fabricated and mounted onto a PCB. The fabricated actuator was tested to demonstrate the feasibility of the fabrication process, sacrificial bridges and SCS TSVs. The results show that the actuator worked well. Its maximum displacement and resonant frequency were 69.9 µm and 406 Hz, respectively. This method is promising for the delivery of a novel 3D system in package for MEMS devices.

Chang, Chao-Min; Chen, Yang-Che; Fong, Chien-Fu; Guu, Yunn-Horng; Chen, Rongshun; Yeh, J. Andrew; Hou, Max T.

2011-09-01

320

A QTL Study for Regions Contributing to Arabidopsis thaliana Root Skewing on Tilted Surfaces.  

PubMed

Plant root systems must grow in a manner that is dictated by endogenous genetic pathways, yet sensitive to environmental input. This allows them to provide the plant with water and nutrients while navigating a heterogeneous soil environment filled with obstacles, toxins, and pests. Gravity and touch, which constitute important cues for roots growing in soil, have been shown to modulate root architecture by altering growth patterns. This is illustrated by Arabidopsis thaliana roots growing on tilted hard agar surfaces. Under these conditions, the roots are exposed to both gravity and touch stimulation. Consequently, they tend to skew their growth away from the vertical and wave along the surface. This complex growth behavior is believed to help roots avoid obstacles in nature. Interestingly, A. thaliana accessions display distinct growth patterns under these conditions, suggesting the possibility of using this variation as a tool to identify the molecular mechanisms that modulate root behavior in response to their mechanical environment. We have used the Cvi/Ler recombinant inbred line population to identify quantitative trait loci that contribute to root skewing on tilted hard agar surfaces. A combination of fine mapping for one of these QTL and microarray analysis of expression differences between Cvi and Ler root tips identifies a region on chromosome 2 as contributing to root skewing on tilted surfaces, potentially by modulating cell wall composition. PMID:22384323

Vaughn, Laura M; Masson, Patrick H

2011-07-01

321

Reproductive partitioning and the assumptions of reproductive skew models in the cooperatively breeding American crow  

PubMed Central

Understanding the benefits of cooperative breeding for group members of different social and demographic classes requires knowledge of their reproductive partitioning and genetic relatedness. From 2004-2007, we examined parentage as a function of relatedness and social interactions among members of 21 American crow (Corvus brachyrhynchos) family groups. Paired female breeders monopolized maternity of all offspring in their broods, whereas paired male breeders sired 82.7% of offspring, within-group auxiliary males sired 6.9% of offspring, and extragroup males sired 10.4% of offspring. Although adult females had fewer opportunities for direct reproduction as auxiliaries than males, they appeared to have earlier opportunities for independent breeding. These different opportunities for direct reproduction probably contributed to the male biased adult auxiliary sex ratio. Patterns of reproductive partitioning and conflict among males were most consistent with a synthetic reproductive skew model, in which auxiliaries struggled with breeders for a limited reproductive share, beyond which breeders could evict them. Counter to a frequent assumption of reproductive skew models, female breeders appeared to influence paternity, although their interests might have agreed with the interests of their paired males. Unusual among cooperative breeders, close inbreeding and incest occurred in this population. Incest avoidance between potential breeders did not significantly affect reproductive skew.

Townsend, Andrea K.; Clark, Anne B.; McGowan, Kevin J.; Lovette, Irby J.

2009-01-01

322

Using skew-logistic probability density function as a model for age-specific fertility rate pattern.  

PubMed

Fertility rate is one of the most important global indexes. Past researchers found models which fit to age-specific fertility rates. For example, mixture probability density functions have been proposed for situations with bi-modal fertility patterns. This model is less useful for unimodal age-specific fertility rate patterns, so a model based on skew-symmetric (skew-normal) pdf was proposed by Mazzuco and Scarpa (2011) which was flexible for unimodal and bimodal fertility patterns. In this paper, we introduce skew-logistic probability density function as a better model: its residuals are less than those of the skew-normal model and it can more precisely estimate the parameters of the model. PMID:24967404

Asili, Sahar; Rezaei, Sadegh; Najjar, Lotfollah

2014-01-01

323

Using Skew-Logistic Probability Density Function as a Model for Age-Specific Fertility Rate Pattern  

PubMed Central

Fertility rate is one of the most important global indexes. Past researchers found models which fit to age-specific fertility rates. For example, mixture probability density functions have been proposed for situations with bi-modal fertility patterns. This model is less useful for unimodal age-specific fertility rate patterns, so a model based on skew-symmetric (skew-normal) pdf was proposed by Mazzuco and Scarpa (2011) which was flexible for unimodal and bimodal fertility patterns. In this paper, we introduce skew-logistic probability density function as a better model: its residuals are less than those of the skew-normal model and it can more precisely estimate the parameters of the model.

Asili, Sahar; Najjar, Lotfollah

2014-01-01

324

Structural Health Indices for Steel Truss Bridges  

Microsoft Academic Search

\\u000a Steel bridges represent a significant portion of the nation’s aging bridge inventory. The United States Army’s inventory has\\u000a over two hundred steel bridges that are vital to the operation of nearly every Army Installation. The Army regularly inspects\\u000a their bridges to ensure the continued functionality of the bridges. However, current inspection techniques and schedules may\\u000a not be able to detect

Ryan Kent Giles; Robin Kim; Billie F. Spencer; M. Nathan; Anne M. Newmark; Lawrence A. Bergman; Carol K. Shield; Steven C. Sweeney

325

Development of Inspection Robots for Bridge Cables  

PubMed Central

This paper presents the bridge cable inspection robot developed in Korea. Two types of the cable inspection robots were developed for cable-suspension bridges and cable-stayed bridge. The design of the robot system and performance of the NDT techniques associated with the cable inspection robot are discussed. A review on recent advances in emerging robot-based inspection technologies for bridge cables and current bridge cable inspection methods is also presented.

Kim, Se-Hoon; Lee, Jong-Jae

2013-01-01

326

Development of inspection robots for bridge cables.  

PubMed

This paper presents the bridge cable inspection robot developed in Korea. Two types of the cable inspection robots were developed for cable-suspension bridges and cable-stayed bridge. The design of the robot system and performance of the NDT techniques associated with the cable inspection robot are discussed. A review on recent advances in emerging robot-based inspection technologies for bridge cables and current bridge cable inspection methods is also presented. PMID:24459453

Yun, Hae-Bum; Kim, Se-Hoon; Wu, Liuliu; Lee, Jong-Jae

2013-01-01

327

Free vibration analysis of skew fibre-reinforced composite laminates based on first-order shear deformation plate theory  

Microsoft Academic Search

Skew fibre-reinforced composite laminates are important structural elements in modern engineering structures, particularly in aero-space industry. Natural frequencies of these skew laminates are of primary significance to structural designers. As far as the author's knowledge is concerned the references on this topic is very limited. Within the context of the first-order shear deformation plate theory (SDPT) [Reissner, The effect of

S. Wang

1997-01-01

328

How the Eight Decision Models Can or Cannot Explain Boiney's Emotional Skewness Effects in Decision Making under Ambiguity  

Microsoft Academic Search

Boiney has recently reported the interesting emotional effects of skewed second- order probability on decision making under ambiguity. This paper examines, using a generalized Boiney problem, how the following eight decision models can or cannot explain Boiney's emotional skewness effects: Keynes Conventional Coefficient Model (1921), Ellsberg Model (1961), Gärdenfors-Sahlin Model (1982), Einhorn-Hogarth Model (1985), Kahn-Sarin Model (1988), Boiney Model (1993),

Jiro IHARA

329

Skew-self-adjoint discrete and continuous Dirac-type systems: inverse problems and Borg Marchenko theorems  

NASA Astrophysics Data System (ADS)

New formulae on the inverse problem for the continuous skew-self-adjoint Dirac-type system are obtained. For the discrete skew-self-adjoint Dirac-type system the solution of a general-type inverse spectral problem is also derived in terms of the Weyl functions. The description of the Weyl functions on the interval is given. Borg-Marchenko-type uniqueness theorems are also derived for both discrete and continuous non-self-adjoint systems.

Sakhnovich, Alexander

2006-12-01

330

Analysis of skewed GPS position estimates: Effects of coupling local topography and atmospheric conditions  

NASA Astrophysics Data System (ADS)

Error in modeling atmospheric delay is one of the limiting factors in the accuracy of GPS position determination. In regions with uneven topography, atmospheric delay phenomena can be especially complicated. Current delay models used in analyzing daily GPS data from the Plate Boundary Observatory (PBO) are successful in achieving millimeter-level accuracy at most locations; however, at a subset of stations, the time-series for position estimates contain an unusually large number of outliers. In many cases these outliers are oriented in the same direction. The stations which exhibit asymmetric outliers occur in various places across the PBO network, but they are especially numerous in California's Mammoth Lakes region, which served as a case study for this presentation. The phenomenon was analyzed by removing secular trends and variations with periods longer than 75 days from the signal using a median filter. We subsequently calculated the skewness of the station position residuals in north, east and up directions. In the cases examined, typical position outliers are 5-15 mm. In extreme cases, skewed position residuals, not related to snow on antennas, can be as large as 20 mm. We examine the causes of the skewness through site-by-site comparisons with topographic data and numerical weather models. Analysis suggests that the direction of the skewness is generally parallel to the local topographic gradient at a scale of several kilometers, and that outlier data points occur when certain atmospheric conditions are met. The results suggest that a coupling between the atmosphere and local topography is responsible for the phenomenon of skewed residuals. In this presentation, we examine the characteristics of the sites that we have analyzed in detail. From these analyses, we postulate possible parameterizations of the atmospheric and topographic effects that could be incorporated into geodetic analysis programs, thus allowing the inhomogeneous atmospheric delays to be estimated in the same way that zenith and gradient atmospheric delay parameters are currently estimated. In addition to explicit estimation, we also explore the possibility of incorporating these effects in position error models, so that the uncertainties in the position estimates are reflective of these effects.

Materna, K.; Herring, T.

2013-12-01

331

Observations of intra-wave suspended sediment transport under acceleration-skewed oscillatory flow  

NASA Astrophysics Data System (ADS)

In the nearshore, waves transform from skewed shoaling waves to asymmetric breaking waves. Velocity skewness, such as found beneath Stokes second-order waves, generally results in a net onshore sediment transport. Recent numerical studies and limited experimental laboratory data have demonstrated the potential importance of acceleration skewness to onshore sediment transport beneath asymmetric, 'saw- tooth' waves. Here, we investigate new full-scale laboratory tunnel experiments under sheetflow conditions in which regular oscillatory sawtooh flow with varying degrees of acceleration skewness and velocity skewness were generated over a mobile bed. In all experiments the velocity amplitude was 1.2 m/s, the wave period was 7 s, and the bed was composed of well-sorted, fine to medium sand (d50 = 200~?m). In several experiments a counter-current of 0.4 m/s was imposed to imitate undertow. We deployed (1) a 2-MHz Acoustical Doppler Velocimeter Profiler (ADVP) to obtain vertical profiles of (phase-averaged) horizontal and vertical oscillatory and turbulent flow with a temporal and vertical resolution of 50 Hz and 3 mm, respectively, and (2) a triple-frequency Acoustical Backscatter Sensor to obtain vertical profiles of (phase-averaged) suspended sediment concentration with a temporal and vertical resolution of 10 Hz and 5 mm, respectively. Under waves with acceleration skewness only, we observed two concentration peaks, which at the top of the sheetflow layer were approximately in phase with the free-stream velocity. As the concentration peak following the rapid acceleration towards maximum onshore flow was slightly larger than the concentration peak under maximum offshore flow, the depth-integrated and wave-averaged suspended transport was directed onshore. While most sediment stirred during the onshore flow phase had settled back to the bed before flow reversal, some sediment stirred during the offshore flow phase persisted into the onshore flow phase, thus providing an additional means for onshore transport. The larger concentration peak under the maximum onshore flow coincided with the observed smaller thickness of the wave boundary layer under maximum onshore flow and with larger velocity gradients, turbulence intensities, and peak bed shear stress ?, where we determined ? from the ADVP data using the acceleration defect integral method. For instance, for a sawtooth wave with ? = amax / (amax + amin) = 0.65, where amax and amin are maximum positive and negative acceleration, respectively, we observed the ratio ?max / |?min| to be approximately 1.3. With an increase in ? and, in particular, with an increase in velocity skewness, we observed ?max / |?min| to increase, the concentration peak under maximum onshore flow to increasingly dominate over that under maximum offshore flow, and the onshore depth-integrated and wave-averaged suspended sediment transport to increase accordingly. In the experiments with a counter current, the wave-induced depth-integrated and wave-averaged suspended sediment transport opposed the direction of wave propagation because sediment concentrations under maximum offshore flow exceeded those under maximum onshore flow.

Ruessink, G.; Michallet, H.; Hurther, D.; Silva, P.

2008-12-01

332

49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312...Interlocking Standards § 236.312 Movable bridge, interlocking of signal appliances with...

2013-10-01

333

Development of Wood Bridges: Prospects of Wood in Various Types of Bridges.  

National Technical Information Service (NTIS)

Economics and aesthetics of various types of wood bridges are considered. The main emphasis is focused on light traffic bridges, but some road bridges are examined, as well. Basic assumptions are specified concerning loading, material properties, allowabl...

A. Jutila A. Tesar H. Rautakorpi L. Salokangas P. Haakana R. Maekpuro

1993-01-01

334

1. Photocopied January 1973 from the Keystone Bridge Company Album, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Photocopied January 1973 from the Keystone Bridge Company Album, 1874. THE KEYSTONE BRIDGE COMPANY: LUCY FURNACE. - Baltimore & Ohio Railroad, Parkersburg Bridge, Ohio River, Parkersburg, Wood County, WV

335

Documentation for assessment of modal pushover-based scaling procedure for nonlinear response history analysis of "ordinary standard" bridges  

USGS Publications Warehouse

The earthquake engineering profession is increasingly utilizing nonlinear response history analyses (RHA) to evaluate seismic performance of existing structures and proposed designs of new structures. One of the main ingredients of nonlinear RHA is a set of ground-motion records representing the expected hazard environment for the structure. When recorded motions do not exist (as is the case for the central United States), or when high-intensity records are needed (as is the case for San Francisco and Los Angeles), ground motions from other tectonically similar regions need to be selected and scaled. The modal-pushover-based scaling (MPS) procedure recently was developed to determine scale factors for a small number of records, such that the scaled records provide accurate and efficient estimates of 'true' median structural responses. The adjective 'accurate' refers to the discrepancy between the benchmark responses and those computed from the MPS procedure. The adjective 'efficient' refers to the record-to-record variability of responses. Herein, the accuracy and efficiency of the MPS procedure are evaluated by applying it to four types of existing 'ordinary standard' bridges typical of reinforced-concrete bridge construction in California. These bridges are the single-bent overpass, multi span bridge, curved-bridge, and skew-bridge. As compared to benchmark analyses of unscaled records using a larger catalog of ground motions, it is demonstrated that the MPS procedure provided an accurate estimate of the engineering demand parameters (EDPs) accompanied by significantly reduced record-to-record variability of the responses. Thus, the MPS procedure is a useful tool for scaling ground motions as input to nonlinear RHAs of 'ordinary standard' bridges.

Kalkan, Erol; Kwong, Neal S.

2010-01-01

336

Assessment of modal-pushover-based scaling procedure for nonlinear response history analysis of ordinary standard bridges  

USGS Publications Warehouse

The earthquake engineering profession is increasingly utilizing nonlinear response history analyses (RHA) to evaluate seismic performance of existing structures and proposed designs of new structures. One of the main ingredients of nonlinear RHA is a set of ground motion records representing the expected hazard environment for the structure. When recorded motions do not exist (as is the case in the central United States) or when high-intensity records are needed (as is the case in San Francisco and Los Angeles), ground motions from other tectonically similar regions need to be selected and scaled. The modal-pushover-based scaling (MPS) procedure was recently developed to determine scale factors for a small number of records such that the scaled records provide accurate and efficient estimates of “true” median structural responses. The adjective “accurate” refers to the discrepancy between the benchmark responses and those computed from the MPS procedure. The adjective “efficient” refers to the record-to-record variability of responses. In this paper, the accuracy and efficiency of the MPS procedure are evaluated by applying it to four types of existing Ordinary Standard bridges typical of reinforced concrete bridge construction in California. These bridges are the single-bent overpass, multi-span bridge, curved bridge, and skew bridge. As compared with benchmark analyses of unscaled records using a larger catalog of ground motions, it is demonstrated that the MPS procedure provided an accurate estimate of the engineering demand parameters (EDPs) accompanied by significantly reduced record-to-record variability of the EDPs. Thus, it is a useful tool for scaling ground motions as input to nonlinear RHAs of Ordinary Standard bridges.

Kalkan, E.; Kwong, N.

2012-01-01

337

Construction Technologies: Create the Strongest Bridge  

NSDL National Science Digital Library

Students work in pairs to create three simple types of model bridges (beam, arch, suspension). They observe quantitatively how the bridges work under load and why engineers use different types of bridges for different places. They also get an idea of the parts needed to build bridges, and their functions. The strength of model bridges is mainly a factor of the quality of materials used, and therefore they do not provide a clear visual representation of tension and compression forces involved. Yet, students are able to see these forces at work in three prototype designs and draw conclusions about their dependence on span, width and supporting structures of the bridge designs.

K-12 Outreach Office,

338

Bridge Construction and Engineering Learning Center  

NSDL National Science Digital Library

This website is a great resource for information on bridges. The site provides links to websites like PBS's Nova, where you can learn about different types of bridges and then test your knowledge by matching the right bridge to the right location (over a freeway, river, canyon or ocean waterway), or where you can read more about the forces, loads and materials that affect bridges. Another link takes you to Better Bridges, where you can find out how many bridges are in your state. Definitely a great resource for those armchair engineers but also for teachers and students of physics looking for some great information on this fascinating type of construction.

339

2.NBT Toll Bridge Puzzle  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: The picture shows islands connected by bridges. To cross a bridge, you must pay a toll in coins. If you start on the island marked in blue with 100 coi...

340

Excitation Methods for Bridge Structures  

SciTech Connect

This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

1999-02-08

341

Level II scour analysis for Bridge 38 (BETHTH00070038) on Town Highway 007, crossing Gilead Brook, Bethel, Vermont  

USGS Publications Warehouse

The town highway 5 crossing of the Black River is a 70-ft-long, two-lane bridge consisting of one 65-foot clear span (Vermont Agency of Transportation, written commun., August 2, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. There is also a retaining wall along the upstream side of the road embankments. The channel is skewed approximately 20 degrees to the opening while the opening-skew-to-roadway is 15 degrees. A scour hole 3.0 ft deeper than the mean thalweg depth was observed along the right abutment. The scour hole was 27 feet long, 15 feet wide, and was 2.5 feet below the abutment footing at the time of the Level I assessment. This right abutment had numerous cracks and had settled. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

Ivanoff, Michael A.; Song, Donald L.

1996-01-01

342

Quantitative analysis of replication-related mutation and selection pressures in bacterial chromosomes and plasmids using generalised GC skew index  

PubMed Central

Background Due to their bi-directional replication machinery starting from a single finite origin, bacterial genomes show characteristic nucleotide compositional bias between the two replichores, which can be visualised through GC skew or (C-G)/(C+G). Although this polarisation is used for computational prediction of replication origins in many bacterial genomes, the degree of GC skew visibility varies widely among different species, necessitating a quantitative measurement of GC skew strength in order to provide confidence measures for GC skew-based predictions of replication origins. Results Here we discuss a quantitative index for the measurement of GC skew strength, named the generalised GC skew index (gGCSI), which is applicable to genomes of any length, including bacterial chromosomes and plasmids. We demonstrate that gGCSI is independent of the window size and can thus be used to compare genomes with different sizes, such as bacterial chromosomes and plasmids. It can suggest the existence of different replication mechanisms in archaea and of rolling-circle replication in plasmids. Correlation of gGCSI values between plasmids and their corresponding host chromosomes suggests that within the same strain, these replicons have reproduced using the same replication machinery and thus exhibit similar strengths of replication strand skew. Conclusions gGCSI can be applied to genomes of any length and thus allows comparative study of replication-related mutation and selection pressures in genomes of different lengths such as bacterial chromosomes and plasmids. Using gGCSI, we showed that replication-related mutation or selection pressure is similar for replicons with similar machinery.

2009-01-01

343

Heat transfer in rotating serpentine passages with trips skewed to the flow  

NASA Technical Reports Server (NTRS)

Experiments were conducted to determine the effects of buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. The experiments were conducted with a large scale, multi-pass, heat transfer model with both radially inward and outward flow. Trip strips, skewed at 45 deg to the flow direction, were machined on the leading and trailing surfaces of the radial coolant passages. An analysis of the governing flow equations showed that four parameters influence the heat transfer in rotating passages: coolant-to-wall temperature, rotation number, Reynolds number, and radius-to-passage hydraulic diameter ratio. The first three of these four parameters were varied over ranges which are typical of advanced gas turbine engine operating conditions. Results were correlated and compared to previous results from similar stationary and rotating models with smooth walls and with trip strips normal to the flow direction. The heat transfer coefficients on surfaces, where the heat transfer decreased with rotation and buoyancy, decreased to as low as 40 percent of the value without rotation. However, the maximum values of the heat transfer coefficients with high rotation were only slightly above the highest levels previously obtained with the smooth wall models. It was concluded that (1) both Coriolis and buoyancy effects must be considered in turbine blade cooling designs with trip strips, (2) the effects of rotation are markedly different depending upon the flow direction, and (3) the heat transfer with skewed trip strips is less sensitive to buoyancy than the heat transfer in models with either smooth or normal trips. Therefore, skewed trip strips rather than normal trip strips are recommended and geometry-specific tests are required for accurate design information.

Johnson, B. V.; Wagner, J. H.; Steuber, G. D.; Yeh, F. C.

1992-01-01

344

Bridges: Chesapeake & Ohio Canal National Monument Historic Structures Report. Part II: Historical Data Section.  

National Technical Information Service (NTIS)

Contents: The Georgetown Bridges 1829-1850; The Georgetown Bridges 1850-1889; Bridges on the Washington Branch; Embankment Bridges; Bridges from College Run to Seneca Aqueduct; Bridges from Seneca Aqueduct to Antietam Aqueduct: Bridges from Antietam Aqued...

1968-01-01

345

Heteroscedastic nonlinear regression models based on scale mixtures of skew-normal distributions.  

PubMed

An extension of some standard likelihood based procedures to heteroscedastic nonlinear regression models under scale mixtures of skew-normal (SMSN) distributions is developed. We derive a simple EM-type algorithm for iteratively computing maximum likelihood (ML) estimates and the observed information matrix is derived analytically. Simulation studies demonstrate the robustness of this flexible class against outlying and influential observations, as well as nice asymptotic properties of the proposed EM-type ML estimates. Finally, the methodology is illustrated using an ultrasonic calibration data. PMID:21731152

Lachos, Victor H; Bandyopadhyay, Dipankar; Garay, Aldo M

2011-08-01

346

Autonomous fault-tolerant attitude reference system using DTGs in symmetrically skewed configuration  

NASA Technical Reports Server (NTRS)

A novel symmetrically skewed configuration for an attitude reference system (ARS) using three dynamically tuned gyros (DTGs) is developed. Simple schemes for autonomous detection and identification of a faulty DTG in real time and subsequent reconfiguration of the attitude estimation algorithm are proposed. The performance of the present configuration is shown to be better than that of configurations proposed earlier, and it is shown to have better features. It tolerates all types of failures of DTG failures, requires very simple computations, and gives less error in attitude estimate than the other configurations.

Murugesan, S.; Goel, P. S.

1989-01-01

347

Excess counterion condensation on polyelectrolyte kinks and branch points and the interaction of skewed charged lines.  

PubMed

We have developed explicit formulas for the excess number of counterions condensed on kinked and intersecting charged lines caused by the more intense electric field in the neighborhood of the kink or intersection. As expected, the number of additionally bound counterions is greater for more pronounced kinks, and also increases with the number of lines that intersect at a common point. We have also analyzed the electrostatic interaction potential as a function of distance between two charged lines in skewed orientation. Our finding in this case is that in a range of close distances the lines must cross a free energy barrier in order to separate. PMID:24686839

Manning, Gerald S

2014-06-01

348

Selective sampling to overcome skewed a priori probabilities with neural networks.  

PubMed Central

Highly skewed a priori probabilities present challenges for researchers developing medical decision aids due to a lack of information on the rare outcome of interest. This paper attempts to overcome this obstacle by artificially increasing the mortality rate of the training sets. A weight pruning technique called weight-elimination is also applied to this coronary artery bypass grafting (CABG) database to assess its impact on the artificial neural network's (ANN) performance. The results showed that increasing the mortality rate improved the sensitivity rates at the cost of the other performance measures, and the weight-elimination cost function improved the sensitivity rate without seriously affecting the other performance measures.

Ennett, C. M.; Frize, M.

2000-01-01

349

Resonant heteroclinic cycles and singular hyperbolic attractors in models for skewed varicose instability  

NASA Astrophysics Data System (ADS)

We consider a system of differential equations proposed by Busse et al (1992 Physica D 61 94-105) to describe the development of spatio-temporal structures in Rayleigh-Bénard convection, near the skewed varicose instability. Numerical computations make it clear that the global bifurcations are organized by a codimension two bifurcation with heteroclinic cycles and a double principal stable eigenvalue at the origin. We carry out the bifurcation study and prove in particular the occurrence in the unfolding of robustly transitive strange attractors akin to Lorenz attractors. In contrast to the actual Lorenz attractors, these attractors contain two equilibria.

Khanh, Nguyen Huu; Homburg, Ale Jan

2005-01-01

350

Prediction of Impact Factor for Military Bridges.  

National Technical Information Service (NTIS)

A numerical study has been conducted on the dynamic response of nonuniform bridges subjected to the passage of heavy, multi-axle vehicles. For practical purposes, short span military bridges are made from lightweight components. As a consequence, the vehi...

V. J. Virchis

1979-01-01

351

Operación IceBridge: Explorando la Antártida  

NASA Video Gallery

Operación IceBridge es una misión aérea de la NASA dedicada a estudiar cambios en el hielo marino y terrestre en ambos polos del planeta. En octubre y noviembre de 2012, IceBridge completó su cuart...

352

Design and Construction of Modern Curved Bridges.  

National Technical Information Service (NTIS)

The overall objectives of this project were to investigate and synthesize state-of-the-art practice for the efficient design and construction of curved bridges, and to identify research needs regarding strength and stability of curved bridges. The project...

J. S. Davidson R. S. Abdalla M. Madhavan

2002-01-01

353

Underwater Inspection and Repair of Bridge Substructures.  

National Technical Information Service (NTIS)

This synthesis will be of special interest to bridge maintenance engineers and others concerned with the inspection and repair of bridge elements below the waterline. Problems with substructures are identified, and procedures, equipment, and techniques cu...

H. C. Lamberton A. J. Sainz R. A. Crawford W. B. Ogletree J. E. Gunn

1981-01-01

354

Stability of Curved Bridges During Construction.  

National Technical Information Service (NTIS)

Because of the increasing demand for curved bridges combined with challenges of design and construction, there is need to improve practices for the efficient design and construction of curved bridges. This report presents the results of two projects aimed...

J. S. Davidson R. S. Abdalla M. Madhavan

2004-01-01

355

Performance Analysis of LAN Bridges and Routers.  

National Technical Information Service (NTIS)

Bridges and routers are used to interconnect Local Area Networks (LANs). The performance of these devices is important since they can become bottlenecks in large multi-segment networks. Performance metrics and test methodology for bridges and routers were...

A. R. Hajare

1991-01-01

356

Mechanics of Crack Bridging Under Dynamic Loads.  

National Technical Information Service (NTIS)

A bridging law for fiber reinforced composites under dynamic crack propagation conditions has been derived. Inertial effects in the mechanism of fiber pullout during dynamic propagation of a bridged crack are critically examined for the first time. By rep...

N. Sridhar B. N. Cox C. L. Dunn I. J. Beyerlein

2001-01-01

357

"Sand Boil" on Bay Bridge  

USGS Multimedia Gallery

"Sand boil" or sand volcano measuring 2 m (6.6 ft) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction). Vented sand contains-marine shell f...

2009-01-26

358

A Bridge to the Future  

ERIC Educational Resources Information Center

Career and technical education (CTE) has a promising future at Darlington (WI) High School. In this article, the author describes how a class bridge project became a real-world, project-based learning opportunity involving higher-level thinking skills that are at the core of CTE at his school. It began when a local citizen approached him at the…

Anderson, Richard

2008-01-01

359

Bridges on the River Quad  

NSDL National Science Digital Library

In this activity, students graph a quadratic function that models the shape of a bridge trestle and then solve the related quadratic equation by completing the square. Students use the calculatorsâ capabilities to find the x-intercepts and the maximum value on the graph. Teacher notes, detailed instructions on using graphing calculators, and questions to check comprehension aid in teaching the lesson.

2011-03-27

360

EOS NPOESS the Bridge Mission  

NSDL National Science Digital Library

A Dynamic proposal between the National Aeronautics and Space Administration and the National Polar Orbiting Environmental Satellite System Integrated Program Office. A project to bridge or link between the operations of the Earth Observing System AM-1 and the PM-1 Spacecraft and the National Polar Orbiting Environmental Satellite System Spacecraft (NPOESS)

Carnahan, Tim; Snodgrass, Stuart; Murphy, Robert

1999-02-02

361

Bridge Standards-Local Governments.  

National Technical Information Service (NTIS)

In the study a survey was conducted to ascertain the needs of employees of local governmental agencies with regard to the conduct of the design of bridges. Recommendations, relative to the development of standard plans which can be used by county engineer...

H. C. Sorensen

1988-01-01

362

Adhesive Development for Military Bridging.  

National Technical Information Service (NTIS)

The objective of this effort was to develop a family of adhesives suited to structural bonding of U.S. Army bridge members. To be joined were: aluminum to aluminum, aluminum to composite, and composite to composite materials. The adhesives should be non-b...

D. I. Basiulis E. Catsiff R. D. Hermansen S. E. Lau W. E. Elias

1988-01-01

363

Evaluation of Summer Bridge Programs  

ERIC Educational Resources Information Center

Many colleges and universities in the United States offer summer programs for their incoming students. While programs are structured and administered in a variety of ways and target various student populations, the most common type of summer bridge program aims to serve historically underrepresented students and students of low socioeconomic…

Garcia, Lisa D.; Paz, Chiara C.

2009-01-01

364

AGU receives Crystal Bridge Award  

Microsoft Academic Search

On 23 June the San Francisco Travel Association presented AGU with its Crystal Bridge Award, given to honor major convention customers who bring outstanding events with significant impact to San Francisco, Calif. For the past 43 years, AGU has held its Fall Meeting in San Francisco; for the past 17 years the meeting has been at San Francisco's Moscone Center.

Brenda Weaver

2011-01-01

365

Evaluating Concrete Bridge Deck Performance.  

National Technical Information Service (NTIS)

Since the service life of concrete bridge decks designed by traditional procedures is often shorter than desired, their ability to withstand constant and heavy use in a variety of operating environments is of major concern. In this project, the relative p...

E. Cuelho J. Johnson J. Stephens P. Smolenski

2006-01-01

366

Parametric studies on cable-stayed bridges  

Microsoft Academic Search

Parametric studies on cable-stayed bridges are performed in the paper for investigating the individual influence of different sources of nonlinearity in such bridges. The sources of nonlinearity in the cable-stayed bridge mainly include the large deflection, beam-column and cable sag effects. The influence of such kind of effects on the analysis and the structural behavior of cable-stayed bridges has been

Pao-Hsii Wang; Chiung-Guei Yang

1996-01-01

367

Suicide from the Golden Gate Bridge.  

PubMed

The Golden Gate Bridge is the number one suicide site in the world. In this clinical case conference, the authors begin by presenting vignettes to capture the diversity of bridge suicide. They then examine the demographic characteristics of those who commit suicide from the bridge as well as the fatal attraction of the Golden Gate Bridge. Interviews with jump survivors and potential jumpers are presented, and the authors examine the evidence for the efficacy of suicide barriers. PMID:19797444

Blaustein, Mel; Fleming, Anne

2009-10-01

368

49 CFR 237.71 - Determination of bridge load capacities.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Determination of bridge load capacities. 237.71 Section 237...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Capacity of Bridges § 237.71 Determination of bridge load...

2010-10-01

369

49 CFR 237.103 - Bridge inspection procedures.  

Code of Federal Regulations, 2010 CFR

... 4 2010-10-01 2010-10-01 false Bridge inspection procedures. 237.103 Section 237...RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.103 Bridge inspection...

2010-10-01

370

49 CFR 237.53 - Railroad bridge inspectors.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Railroad bridge inspectors. 237.53 Section 237...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Qualifications and...Responsible Persons § 237.53 Railroad bridge inspectors. A railroad bridge...

2013-10-01

371

49 CFR 237.109 - Bridge inspection records.  

Code of Federal Regulations, 2010 CFR

... 4 2010-10-01 2010-10-01 false Bridge inspection records. 237.109 Section 237...RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.109 Bridge inspection...

2010-10-01

372

33 CFR 118.90 - Bridges crossing channel obliquely.  

Code of Federal Regulations, 2013 CFR

...Waters 1 2013-07-01 2013-07-01 false Bridges crossing channel obliquely. 118.90 Section 118...Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges...

2013-07-01

373

49 CFR 237.111 - Review of bridge inspection reports.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Review of bridge inspection reports. 237.111 Section 237...RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.111 Review of bridge...

2013-10-01

374

49 CFR 237.109 - Bridge inspection records.  

Code of Federal Regulations, 2013 CFR

... 4 2013-10-01 2013-10-01 false Bridge inspection records. 237.109 Section 237...RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.109 Bridge inspection...

2013-10-01

375

49 CFR 237.103 - Bridge inspection procedures.  

Code of Federal Regulations, 2013 CFR

... 4 2013-10-01 2013-10-01 false Bridge inspection procedures. 237.103 Section 237...RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.103 Bridge inspection...

2013-10-01

376

49 CFR 237.71 - Determination of bridge load capacities.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Determination of bridge load capacities. 237.71 Section 237...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Capacity of Bridges § 237.71 Determination of bridge load...

2013-10-01

377

49 CFR 237.107 - Conduct of bridge inspections.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Conduct of bridge inspections. 237.107 Section 237.107 ...RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.107 Conduct of bridge...

2013-10-01

378

Simultaneous Bayesian inference for skew-normal semiparametric nonlinear mixed-effects models with covariate measurement errors  

PubMed Central

Longitudinal data arise frequently in medical studies and it is a common practice to analyze such complex data with nonlinear mixed-effects (NLME) models which enable us to account for between-subject and within-subject variations. To partially explain the variations, covariates are usually introduced to these models. Some covariates, however, may be often measured with substantial errors. It is often the case that model random error is assumed to be distributed normally, but the normality assumption may not always give robust and reliable results, particularly if the data exhibit skewness. Although there has been considerable interest in accommodating either skewness or covariate measurement error in the literature, there is relatively little work that considers both features simultaneously. In this article, our objectives are to address simultaneous impact of skewness and covariate measurement error by jointly modeling the response and covariate processes under a general framework of Bayesian semiparametric nonlinear mixed-effects models. The method is illustrated in an AIDS data example to compare potential models which have different distributional specifications. The findings from this study suggest that the models with a skew-normal distribution may provide more reasonable results if the data exhibit skewness and/or have measurement errors in covariates.

Huang, Yangxin; Dagne, Getachew A.

2012-01-01

379

47 CFR 80.309 - Watch required by the Bridge-to-Bridge Act.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Watch required by the Bridge-to-Bridge Act. 80.309 Section 80.309 Telecommunication...Safety Watches § 80.309 Watch required by the Bridge-to-Bridge Act. In addition to the watch...

2013-10-01

380

47 CFR 80.163 - Operator requirements of the Bridge-to-Bridge Act.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Operator requirements of the Bridge-to-Bridge Act. 80.163 Section 80.163 Telecommunication...Requirements § 80.163 Operator requirements of the Bridge-to-Bridge Act. Each ship subject to the...

2013-10-01

381

Bridge Programs in Illinois: Results of the 2010 Illinois Bridge Status Survey  

ERIC Educational Resources Information Center

This report provides a summary of major results of the Illinois Bridge Status Survey, administered online between April and June 2010. The purpose of the survey was to understand the extent to which bridge programs are being implemented in Illinois, as well as to build an online directory of bridge programs. Bridge programs are an emerging…

Taylor, J. L.; Harmon, T.

2010-01-01

382

A Participatory Public Art Project: Community Bridge  

ERIC Educational Resources Information Center

This article introduces Community Bridge, a participatory public art project that brought together artists and residents to address aesthetic needs of an urban environment. The Community Bridge is an exemplary work of art by American artist William Cochran. In addition to creating a natural gathering place for residents of all ages, the bridge is…

Stephens, Pam

2005-01-01

383

Remediation: Higher Education's Bridge to Nowhere  

ERIC Educational Resources Information Center

The intentions were noble. It was hoped that remediation programs would be an academic bridge from poor high school preparation to college readiness. Sadly, remediation has become instead higher education's "Bridge to Nowhere." This broken remedial bridge is travelled by some 1.7 million beginning students each year, most of whom will not reach…

Complete College America, 2012

2012-01-01

384

Rehabilitation of Precast Deck Panel Bridges  

Microsoft Academic Search

USF completed a research study in 2005, which prioritized the replacement of 85 deteriorating composite precast deck panel bridges. This thesis re-evaluates the original recommendations in the wake of failures of two of these bridges in 2007. Since funding will not allow all identified bridges to be replaced, it was necessary to determine the most effective repair methods. To assess

Atiq H. Alvi

2010-01-01

385

Shake Table Testing of Lightweight Concrete Bridges.  

National Technical Information Service (NTIS)

This report is the third in a series on the seismic behavior of lightweight concrete bridges. Presented are the results of a series of shake table tests on lightweight concrete bridges. A pair of two column bridge bents were designed and tested on the UCS...

F. Seible M. Kowalsky N. Priestley

1997-01-01

386

Probalistic analysis of highway bridge traffic loading  

Microsoft Academic Search

Many bridges of the world’s highway networks have been in service for decades and are subject to escalating volumes of traffic. Consequently, there is a growing need for the rehabilitation or replacement of bridges due to deterioration and increased loading. The assessment of the strength of the existing bridge is relatively well understood, whereas the traffic loading it is subject

Colin C. Caprani

2005-01-01

387

Structural behaviour of aluminium bridge deck panels  

Microsoft Academic Search

The use of lightweight bridge decks made of FRP composites or aluminium alloys is particularly effective for replacing deteriorated bridge decks. Therefore a research program has been undertaken to develop and implement an innovative aluminium bridge deck system, which would be applicable and realizable in domestic conditions. Several service load and ultimate load tests have been carried out on the

Tomasz W. Siwowski

2009-01-01

388

The breaking of axisymmetric slender liquid bridges  

Microsoft Academic Search

Liquids held by surface tension forces can bridge the gap between two solid bodies placed not too far apart from each other. The equilibrium conditions and stability criteria for static, cylindrical liquid bridges are well known. However, the behaviour of an unstable liquid bridge, regarding both its transition toward breaking and the resulting configuration, is a matter for discussion. The

J. Meseguer

1983-01-01

389

Development of a contour map showing generalized skew coefficients of annual peak discharges of rural, unregulated streams in New York, excluding Long Island  

USGS Publications Warehouse

Flood-frequency relations that are developed by fitting the logarithms of annual peak discharges to a Pearson Type-III distribution are sensitive to skew coefficients. Estimates of population skew for a site are improved when computed from the weighted average of (1) the sample (station) skew, and (2) an unbiased, generalized skew estimate. A weighting technique based on the number of years of record at each of 226 sites was used to develop a contour map of unbiased, generalized skew coefficients for New York. An attempt was made to group (regionalize) the station skew coefficients into five hydrologically similar areas of New York, but the statewide version proved to be as accurate as the regionalized version and therefore was adopted as the final generalized skew-coefficient map for New York. An error analysis showed the statewide contour map to have lower MSE?s (mean square errors) than those computed from (1) the five regional skewcoefficient contour maps, (2) a previously used (1982) nationwide skew coefficient map, and (3) the weighted mean of skew coefficients for sites within each of five hydrologically uniform, but distinct areas of New York.

Lumia, Richard; Baevsky, Yvonne Halpern

2000-01-01

390

Langevin equation modeling of convective boundary layer dispersion assuming homogeneous, skewed turbulence  

SciTech Connect

Vertical dispersion of material in the convective boundary layer, CBL, is dramatically different than in natural or stable boundary layers, as has been shown by field and laboratory experiments. Lagrangian stochastic modeling based on the Langevin equation has been shown to be useful for simulating vertical dispersion in the CBL. This modeling approach can account for the effects of the long Lagrangian time scales (associated with large-scale turbulent structures), skewed vertical velocity distributions, and vertically inhomogeneous turbulent properties found in the CBL. It has been recognized that simplified Langevin equation models that assume skewed but homogeneous velocity statistics can capture the important aspects of dispersion from sources the the CBL. The assumption of homogeneous turbulence has a significant practical advantage, specifically, longer time steps can be used in numerical simulations. In this paper, we compare two Langevin equations models that use the homogeneous turbulence assumption. We also compare and evaluate three reflection boundary conditions, the method for determining a new velocity for a particle that encounters a boundary. Model results are evaluated using data from Willis and Deardorff`s laboratory experiments for three different source heights.

Hasstrom, J.S.; Ermak, D.L.

1997-10-01

391

Differential properties and attracting sets of a simplest skew product of interval maps  

SciTech Connect

For a skew product of interval maps with a closed set of periodic points, the dependence of the structure of its {omega}-limit sets on its differential properties is investigated. An example of a map in this class is constructed which has the maximal differentiability properties (within a certain subclass) with respect to the variable x, is C{sup 1}-smooth in the y-variable and has one-dimensional {omega}-limit sets. Theorems are proved that give necessary conditions for one-dimensional {omega}-limit sets to exist. One of them is formulated in terms of the divergence of the series consisting of the values of a function of x; this function is the C{sup 0}-norm of the deviation of the restrictions of the fibre maps to some nondegenerate closed interval from the identity on the same interval. Another theorem is formulated in terms of the properties of the partial derivative with respect to x of the fibre maps. A complete description is given of the {omega}-limit sets of certain class of C{sup 1}-smooth skew products satisfying some natural conditions. Bibliography: 33 titles.

Efremova, Lyudmila S [N. I. Lobachevski State University of Nizhni Novgorod, Nizhnii Novgorod (Russian Federation)

2010-08-12

392

Skew-symmetric convection form and secondary conservative finite difference methods for moving grids  

NASA Astrophysics Data System (ADS)

The secondary conservative finite difference method for the convective term is recognized as a useful tool for unsteady flow simulations. However, the secondary conservative convection scheme and associated skew-symmetric form have not been extended to those for moving grids. In this study, the skew-symmetric form and the secondary conservative convection schemes for ALE type moving grid simulations are proposed. For the moving grid simulations, the geometric conservation law (GCL) for metrics and the Jacobian is known as a mathematical constraint for capturing a uniform flow. A new role of the GCL is revealed in association with the commutability and conservation properties of the convection schemes. The secondary conservative convection schemes for moving grids are then constructed for compressible and incompressible flows, respectively. For compressible flows, it is necessary to introduce a shock capturing method to resolve discontinuities. However, the shock capturing methods do not work well for turbulent flow simulations because of their excessive numerical dissipation. On the other hand, the secondary conservative finite difference method does not work well for flows with discontinuities. In this study, we also present a computational technique that combines the shock capturing and the secondary conservative finite difference methods. In order to check the commutability and conservation properties of the convection schemes, numerical tests are done for compressible and incompressible inviscid periodic flows on moving grids. Then, the reliabilities of the schemes are demonstrated on the piston problem, the flow around pitching airfoil, and the flow around an oscillating square cylinder.

Morinishi, Yohei; Koga, Kazuki

2014-01-01

393

Weighted skewness and kurtosis unbiased by sample size and Gaussian uncertainties  

NASA Astrophysics Data System (ADS)

Central moments and cumulants are often employed to characterize the distribution of data. The skewness and kurtosis are particularly useful for the detection of outliers, the assessment of departures from normally distributed data, automated classification techniques and other applications. Estimators of higher order moments that are robust against outliers are more stable but might miss characteristic features of the data, as in the case of astronomical time series exhibiting brief events like stellar bursts or eclipses of binary systems, while weighting can help identify reliable measurements from uncertain or spurious outliers. Furthermore, noise is an unavoidable part of most measurements and their uncertainties need to be taken properly into account during the data analysis or biases are likely to emerge in the results, including basic descriptive statistics. This work provides unbiased estimates of the weighted skewness and kurtosis moments and cumulants, corrected for biases due to sample size and Gaussian noise, under the assumption of independent data. A comparison of biased and unbiased weighted estimators is illustrated with simulations as a function of sample size and signal-to-noise ratio, employing different data distributions and weighting schemes related to measurement uncertainties and the sampling of the signal. Detailed derivations and figures of simulation results are presented in the Appendices available online.

Rimoldini, Lorenzo

2014-07-01

394

Fuel cell plates with skewed process channels for uniform distribution of stack compression load  

DOEpatents

An electrochemical fuel cell includes an anode electrode, a cathode electrode, an electrolyte matrix sandwiched between electrodes, and a pair of plates above and below the electrodes. The plate above the electrodes has a lower surface with a first group of process gas flow channels formed thereon and the plate below the electrodes has an upper surface with a second group of process gas flow channels formed thereon. The channels of each group extend generally parallel to one another. The improvement comprises the process gas flow channels on the lower surface of the plate above the anode electrode and the process gas flow channels on the upper surface of the plate below the cathode electrode being skewed in opposite directions such that contact areas of the surfaces of the plates through the electrodes are formed in crisscross arrangements. Also, the plates have at least one groove in areas of the surfaces thereof where the channels are absent for holding process gas and increasing electrochemical activity of the fuel cell. The groove in each plate surface intersects with the process channels therein. Also, the opposite surfaces of a bipolar plate for a fuel cell contain first and second arrangements of process gas flow channels in the respective surfaces which are skewed the same amount in opposite directions relative to the longitudinal centerline of the plate.

Granata, Jr., Samuel J. (Greensburg, PA); Woodle, Boyd M. (North Huntingdon Township, Westmoreland County, PA) [North Huntingdon Township, Westmoreland County, PA

1989-01-01

395

Performance of five two-sample location tests for skewed distributions with unequal variances.  

PubMed

Tests for comparing the locations of two independent populations are associated with different null hypotheses, but results are often interpreted as evidence for or against equality of means or medians. We examine the appropriateness of this practice by investigating the performance of five frequently used tests: the two-sample T test, the Welch U test, the Yuen-Welch test, the Wilcoxon-Mann-Whitney test, and the Brunner-Munzel test. Under combined violations of normality and variance homogeneity, the true significance level and power of the tests depend on a complex interplay of several factors. In a wide ranging simulation study, we consider scenarios differing in skewness, skewness heterogeneity, variance heterogeneity, sample size, and sample size ratio. We find that small differences in distribution properties can alter test performance markedly, thus confounding the effort to present simple test recommendations. Instead, we provide detailed recommendations in Appendix A. The Welch U test is recommended most frequently, but cannot be considered an omnibus test for this problem. PMID:19577012

Fagerland, Morten W; Sandvik, Leiv

2009-09-01

396

Empirical validation of stochastic models of interacting agents. A ``maximally skewed'' noise trader model  

NASA Astrophysics Data System (ADS)

The present paper expands on recent attempts at estimating the parameters of simple interacting-agent models of financial markets [S. Alfarano, T. Lux, F. Wagner, Computational Economics 26, 19 (2005); S. Alfarano, T. Lux, F. Wagner, in Funktionsfähigkeit und Stabilität von Finanzmärkten, edited by W. Franz, H. Ramser, M. Stadler (Mohr Siebeck, Tübingen, 2005), pp. 241 254]. Here we provide additional evidence by (i) investigating a large sample of individual stocks from the Tokyo Stock Exchange, and (ii) comparing results from the baseline noise trader/fundamentalist model of [S. Alfarano, T. Lux, F. Wagner, Computational Economics 26, 19 (2005)] with those obtained from an even simpler version with a preponderance of noise trader behaviour. As it turns out, this somewhat more parsimonious “maximally skewed” variant is often not rejected in favor of the more complex version. We also find that all stocks are dominated by noise trader behaviour irrespective of whether the data prefer the skewed or the baseline version of our model.

Alfarano, S.; Lux, T.; Wagner, F.

2007-01-01

397

Heat transfer in rotating serpentine passages with trips skewed to the flow  

NASA Technical Reports Server (NTRS)

Experiments were conducted to determine the effects of buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. The experiments were conducted with a large scale, multi-pass heat transfer model with both radially inward and outward flow. An analysis of the governing flow equations showed that four parameters influence the heat transfer in rotating passages: coolant-to-wall temperature, rotation number, Reynolds number, and radius-to-passage hydraulic diameter ratio. Results were correlated and compared to previous results from similar stationary and rotating models with smooth walls and with trip strips normal to the flow direction. It was concluded that (1) both Coriolis and buoyancy must be considered in turbine blade cooling designs with trip strips, (2) the effects of rotation are markedly different depending upon the flow direction, and (3) the heat transfer with skewed trip strips is less sensitive to buoyancy than the heat transfer models with either smooth or normal trips. Therefore, skewed trip strips rather than normal trip strips are recommended and geometry-specific tests are required for accurate design.

Johnson, B. V.; Wagner, J. H.; Steuber, G. D.; Yeh, F. C.

1992-01-01

398

Performance analysis of LAN bridges and routers  

NASA Technical Reports Server (NTRS)

Bridges and routers are used to interconnect Local Area Networks (LANs). The performance of these devices is important since they can become bottlenecks in large multi-segment networks. Performance metrics and test methodology for bridges and routers were not standardized. Performance data reported by vendors is not applicable to the actual scenarios encountered in an operational network. However, vendor-provided data can be used to calibrate models of bridges and routers that, along with other models, yield performance data for a network. Several tools are available for modeling bridges and routers - Network II.5 was used. The results of the analysis of some bridges and routers are presented.

Hajare, Ankur R.

1991-01-01

399

Theory of water and charged liquid bridges  

NASA Astrophysics Data System (ADS)

The phenomenon of liquid bridge formation due to an applied electric field is investigated. A solution of a charged catenary is presented, which allows one to determine the static and dynamical stability conditions where charged liquid bridges are possible. The creeping height, the bridge radius and length, as well as the shape of the bridge are calculated showing an asymmetric profile, in agreement with observations. The flow profile is calculated from the Navier-Stokes equation leading to a mean velocity, which combines charge transport with neutral mass flow and which describes recent experiments on water bridges.

Morawetz, K.

2012-08-01

400

Diode-quad bridge circuit means  

NASA Technical Reports Server (NTRS)

Diode-quad bridge circuit means is described for use as a transducer circuit or as a discriminator circuit. It includes: (1) a diode bridge having first, second, third, and fourth bridge terminals consecutively coupled together by four diodes polarized in circulating relationship; (2) a first impedance connected between the second bridge terminal and a circuit ground; (3) a second impedance connected between the fourth bridge terminal and the circuit ground; (4) a signal source having a first source terminal capacitively coupled to the first and third bridge terminals, and a second source terminal connected to the circuit ground; and (5) an output terminal coupled to the first bridge terminal and at which an output signal may be taken.

Harrison, D. R.; Dimeff, J. (inventors)

1975-01-01

401

FAST TRACK COMMUNICATION: Non-skew-symmetric classical r-matrices and integrable cases of the reduced BCS model  

NASA Astrophysics Data System (ADS)

We consider generalized quantum Gaudin systems in an external magnetic field associated with non-skew-symmetric sl(2)-valued classical r-matrices. We calculate spectra of the generating function of the corresponding Hamiltonians using the algebraic Bethe ansatz. We apply these results to the construction of integrable fermionic Hamiltonians of a generalized BCS type. We investigate the special cases when the corresponding integrable Hamiltonians contain only a pairing interaction term and consider an example of such a situation associated with a special non-skew-symmetric r-matrix.

Skrypnyk, T.

2009-11-01

402

Robot-Assisted Bridge Inspection  

Microsoft Academic Search

The Center for Robot-Assisted Search and Rescue (CRASAR®) deployed a customized AEOS man-portable unmanned surface vehicle\\u000a and two commercially available underwater vehicles (the autonomous YSI EcoMapper and the tethered VideoRay) for inspection\\u000a of the Rollover Pass bridge in the Bolivar peninsula of Texas in the aftermath of Hurricane Ike. A preliminary domain analysis\\u000a with the vehicles identified key tasks in

Robin R. Murphy; Eric Steimle; Michael Hall; Michael Lindemuth; David Trejo; Stefan Hurlebaus; Zenon Medina-Cetina; Daryl Slocum

403

Bridging Nonliving and Living Matter  

Microsoft Academic Search

Assembling non-biological materials (geomaterials) into a proto-organism constitutes a bridge between nonliving and living matter. In this article we present a simple step-by-step route to assemble a proto-organism. Many pictures have been proposed to describe this transition within the origins-of-life and artificial life communities, and more recently alternative pictures have been emerging from advances in nanoscience and biotechnology. The proposed

Steen Rasmussen; Liaohai Chen; Martin Nilsson; Shigeaki Abe

2003-01-01

404

Heterotriangulenes ?-Expanded at Bridging Positions.  

PubMed

A series of nitrogen-containing heterotriangulenes expanded at the bridging positions has been synthesized. Among them, a dibenzo[c,g]fluorenylidene-substituted derivative has a highly twisted conformation for the overcrowded alkene moieties, which impart a highly electron-accepting character to the electron-donating heterotriangulene skeleton and thereby an NIR absorption as well as multiredox properties with a low reduction potential. PMID:24851675

Chou, Chih-Ming; Saito, Shohei; Yamaguchi, Shigehiro

2014-06-01

405

Skart: A skewness- and autoregression-adjusted batch-means procedure for simulation analysis  

NASA Astrophysics Data System (ADS)

We discuss Skart, an automated batch-means procedure for constructing a skewness- and autoregression-adjusted confidence interval (CI) for the steady-state mean of a simulation output process in either discrete time (i.e., observation-based statistics) or continuous time (i.e., time-persistent statistics). Skart is a sequential procedure designed to deliver a CI that satisfies user-specified requirements concerning not only the CI's coverage probability but also the absolute or relative precision provided by its half-length. Skart exploits separate adjustments to the half-length of the classical batchmeans CI so as to account for the effects on the distribution of the underlying Student's t-statistic that arise from skewness (nonnormality) and autocorrelation of the batch means. The skewness adjustment is based on a modified Cornish-Fisher expansion for the classical batch-means Student's t -ratio, and the autocorrelation adjustment is based on an autoregressive approximation to the batch-means process for sufficiently large batch sizes. Skart also delivers a point estimator for the steady-state mean that is approximately free of initialization bias. The duration of the associated warm-up period (i.e., the statistics clearing time) is based on iteratively applying von Neumann's randomness test to spaced batch means with progressively increasing batch sizes and interbatch spacer sizes. In an experimental performance evaluation involving a wide range of test processes, Skart compared favorably with other simulation analysis methods---namely, its predecessors ASAP3, WASSP, and SBatch as well as ABATCH, LBATCH, the Heidelberger-Welch procedure, and the Law-Carson procedure. Specifically, Skart exhibited competitive sampling efficiency and substantially closer conformance to the given CI coverage probabilities than the other procedures. Also presented is a nonsequential version of Skart, called N-Skart, in which the user supplies a single simulation-generated series of arbitrary length and specifies a coverage probability for a CI based on that series. In the same set of test processes previously mentioned and for a range of data-set sizes, N-Skart also achieved close conformance to the specified CI coverage probabilities.

Tafazzoli Yazdi, Ali

406

Molecular bridging of silicon nanogaps.  

PubMed

The highly doped electrodes of a vertical silicon nanogap device have been bridged by a 5.85 nm long molecular wire, which was synthesized in situ by grafting 4-ethynylbenzaldehyde via C-Si links to the top and bottom electrodes and thereafter by coupling an amino-terminated fluorene unit to the aldehyde groups of the activated electrode surfaces. The number of bridging molecules is constrained by relying on surface roughness to match the 5.85 nm length with an electrode gap that is nominally 1 nm wider and may be controlled by varying the reaction time: the device current increases from ?1 pA at 1 V following the initial grafting step to 10-100 nA at 1 V when reacted for 5-15 min with the amino-terminated linker and 10 ?A when reacted for 16-53 h. It is the first time that both ends of a molecular wire have been directly grafted to silicon electrodes, and these molecule-induced changes are reversible. The bridges detach when the device is rinsed with dilute acid solution, which breaks the imine links of the in situ formed wire and causes the current to revert to the subpicoampere leakage value of the 4-ethynylbenzaldehyde-grafted nanogap structure. PMID:21082817

Ashwell, Geoffrey J; Phillips, Laurie J; Robinson, Benjamin J; Urasinska-Wojcik, Barbara; Lambert, Colin J; Grace, Iain M; Bryce, Martin R; Jitchati, Rukkiat; Tavasli, Mustafa; Cox, Timothy I; Sage, Ian C; Tuffin, Rachel P; Ray, Shona

2010-12-28

407

Scour assessment at bridges from Flag Point to Million Dollar Bridge, Copper River Highway, Alaska  

USGS Publications Warehouse

Twelve bridges are located along the Copper River Highway from Flag Point (Mile 27) to lhe Million Dollar Bridge (Mile 48). These bridges cross all or parts of the Copper River. Channel scour at these bridges was assessed by collecting and analyzing discharge and sediment data, analyzing aerial photography for eight different years, surveying and comparing cross sections, and utilizing scour equations. Between 1968 and 1992, scour occurring at Bridge 331 has formed two distinct channels at the bridge. The channel at Bridge 1187 has remained relatively unchanged between 1968 and 1992. During this same time period, the channel at Bridge 332 appears to have gradually filled. However, during the 1992 runoff season, the channel at this bridge scoured significantly, probably because of its unstable nature. The most significant scour has occurred at Bridge 342. A high-water period in 1981 probably shifted much of the flow of the Copper River through this bridge. As a result, severe contraction scour occurred which required major repairs to the bridge. During 1991 and 1992, the approach channel to Bridge 342 has been migrating, causing scour in the left side of the channel. Bed material at the Million Dollar Bridge consists of hard unweathered boulders nested in dense gravel. Because of this type of erosion-resistant material, no significant scour has occurred at this site. Contraction scour equations overestimated the mean depth of flow at Bridge 331 by 2.6 to 5.0 ft, but were within 1.0 ft of the mean depth of flow for Bridge 1187. The local scour equations generally overestimated local scour at both Bridge 331 and Bridge 1187. The accuracy of some equations was probably affected because water velocities could not be obtained upstream from the piers.

Brabets, T. P.

1994-01-01

408

Reynolds number effect on the velocity increment skewness in isotropic turbulence  

NASA Astrophysics Data System (ADS)

Second and third order longitudinal structure functions and wavenumber spectra of isotropic turbulence are computed using the eddy-damped quasi-normal Markovian model (EDQNM) and compared to results of the multifractal formalism. It is shown that both the multifractal model and EDQNM give power-law corrections to the inertial range scaling of the velocity increment skewness. For the multifractal formalism, this is an intermittency correction that persists at any high Reynolds number. For EDQNM, this correction is a finite Reynolds number effect, and it is shown that very high Reynolds numbers are needed for this correction to become insignificant with respect to intermittency corrections. Furthermore, the two approaches yield realistic behavior of second and third order statistics of the velocity fluctuations in the dissipative and near-dissipative ranges. Similarities and differences are highlighted, in particular, the Reynolds number dependence.

Bos, Wouter J. T.; Chevillard, Laurent; Scott, Julian F.; Rubinstein, Robert

2012-01-01

409

A Novel Generalized Normal Distribution for Human Longevity and other Negatively Skewed Data  

PubMed Central

Negatively skewed data arise occasionally in statistical practice; perhaps the most familiar example is the distribution of human longevity. Although other generalizations of the normal distribution exist, we demonstrate a new alternative that apparently fits human longevity data better. We propose an alternative approach of a normal distribution whose scale parameter is conditioned on attained age. This approach is consistent with previous findings that longevity conditioned on survival to the modal age behaves like a normal distribution. We derive such a distribution and demonstrate its accuracy in modeling human longevity data from life tables. The new distribution is characterized by 1. An intuitively straightforward genesis; 2. Closed forms for the pdf, cdf, mode, quantile, and hazard functions; and 3. Accessibility to non-statisticians, based on its close relationship to the normal distribution.

Robertson, Henry T.; Allison, David B.

2012-01-01

410

B Cells Promote Th1- Skewed NKT Cell Response by CD1d-TCR Interaction.  

PubMed

CD1d expressing dendritic cells (DCs) are good glyco-lipid antigen presenting cells for NKT cells. However, resting B cells are very weak stimulators for NKT cells. Although ?-galactosylceramide (?-GalCer) loaded B cells can activate NKT cells, it is not well defined whether B cells interfere NKT cell stimulating activity of DCs. Unexpectedly, we found in this study that B cells can promote Th1-skewed NKT cell response, which means a increased level of IFN-? by NKT cells, concomitant with a decreased level of IL-4, in the circumstance of co-culture of DCs and B Cells. Remarkably, the response promoted by B cells was dependent on CD1d expression of B cells. PMID:24198748

Shin, Jung Hoon; Park, Se-Ho

2013-10-01

411

Skew orthogonal polynomials for the real and quaternion real Ginibre ensembles and generalizations  

NASA Astrophysics Data System (ADS)

There are some distinguished ensembles of non-Hermitian random matrices for which the joint probability density function can be written down explicitly, are unchanged by rotations, and furthermore which have the property that the eigenvalues form a Pfaffian point process. For these ensembles, in which the elements of the matrices are either real, or real quaternion, the kernel of the Pfaffian is completely determined by certain skew orthogonal polynomials, which permit an expression in terms of averages over the characteristic polynomial, and the characteristic polynomial multiplied by the trace. We use Schur polynomial theory, knowledge of the value of a Schur polynomial averaged against real, and real quaternion Gaussian matrices, and the Selberg integral to evaluate these averages.

Forrester, Peter J.

2013-06-01

412

Obliterable of graphics and correction of skew using Hough transform for mobile captured documents  

NASA Astrophysics Data System (ADS)

CBDA is an emerging field in Computer Vision and Pattern Recognition. In recent technology camera are incorporated to several electronic equipments and are very interesting and thus playing a vital role by replacing scanner with hand held imaging devices like Digital Cameras, Mobile phones and gaming devices attached with these camera. The goal of the work is to remove graphics from the document which plays a vital role in recognition of characters from the mobile captured documents. In this paper we have proposed a novel method for separating or removal of graphics like logos, animations other than the text from the document and method to reduce noise and finally textual content skew is estimated and corrected using Hough Transform. The experimental results show the efficacy compared to the result of well known existing methods.

Chethan, H. K.; Kumar, G. Hemantha

2011-10-01

413

Simple form for the low-x generalized parton distributions in the skewed regime  

NASA Astrophysics Data System (ADS)

We show that the generalized parton distribution functions (GPDFs) in the “skewed” x???1 regime can be related in a particularly simple way to the usual diagonal distributions. This follows directly from the Shuvaev transform but bypasses a direct evaluation of the poorly convergent double integral which this relation contains, thus allowing for a more transparent understanding of the physics involved; it avoids the necessity for any further low-x approximations for the diagonal partons as well as permits a clearer application to cases when the GPDFs unintegrated over the parton transverse momentum are required. We consider for illustration the specific examples of the central exclusive production of a standard model Higgs boson, and the photoproduction of J/? and ? mesons at the LHC, and show how a careful evaluation of the GPDFs, which our simple results allow, is required to correctly calculate the predicted cross sections.

Harland-Lang, L. A.

2013-08-01

414

Remote sensing for bridge health monitoring  

NASA Astrophysics Data System (ADS)

This paper addresses the potential applications of commercial remote sensing (CRS) technologies for bridge monitoring. High resolution optical-photonic images can provide bridge damage information including through-deck collision damages, large permanent deformations, overload cracking and surface erosions, as well as surrounding environmental information. This paper summaries bridge issues that can be detected from high resolution remote sensing imageries based on visual interpretation as guidance for remote sensing imagery based bridge inspection, and the development of future automatic detection methods. A LiDAR based automatic bridge evaluation system LiBE (LiDAR Bridge Evaluation) is introduced in this paper with an application example of a test bridge maintained by the Los Angeles County (CA) Department of Public Works. Laser scanning techniques have also been used for bridge load testing in a new bridge near Charlotte, NC and maintained by the North Carolina DOT. The primary results of these preliminary tests are also presented. Remote sensing techniques are introduced as a supplement to the existing, required visual bridge inspections.

Liu, Wanqiu; Chen, She-Een; Hauser, Edd

2009-08-01

415

Th1-skewed tissue responses to a mycolyl glycolipid in mycobacteria-infected rhesus macaques  

SciTech Connect

Highlights: •Glucose monomycolate (GMM) is a marker glycolipid for active tuberculosis. •Tissue responses to GMM involved up-regulation of Th1-attracting chemokines. •Th1-skewed local responses were mounted at the GMM-injected tissue. -- Abstract: Trehalose 6,6?-dimycolate (TDM) is a major glycolipid of the cell wall of mycobacteria with remarkable adjuvant functions. To avoid detection by the host innate immune system, invading mycobacteria down-regulate the expression of TDM by utilizing host-derived glucose as a competitive substrate for their mycolyltransferases; however, this enzymatic reaction results in the concomitant biosynthesis of glucose monomycolate (GMM) which is recognized by the acquired immune system. GMM-specific, CD1-restricted T cell responses have been detected in the peripheral blood of infected human subjects and monkeys as well as in secondary lymphoid organs of small animals, such as guinea pigs and human CD1-transgenic mice. Nevertheless, it remains to be determined how tissues respond at the site where GMM is produced. Here we found that rhesus macaques vaccinated with Mycobacterium bovis bacillus Calmette–Guerin mounted a chemokine response in GMM-challenged skin that was favorable for recruiting T helper (Th)1 T cells. Indeed, the expression of interferon-?, but not Th2 or Th17 cytokines, was prominent in the GMM-injected tissue. The GMM-elicited tissue response was also associated with the expression of monocyte/macrophage-attracting CC chemokines, such as CCL2, CCL4 and CCL8. Furthermore, the skin response to GMM involved the up-regulated expression of granulysin and perforin. Given that GMM is produced primarily by pathogenic mycobacteria proliferating within the host, the Th1-skewed tissue response to GMM may function efficiently at the site of infection.

Morita, Daisuke; Miyamoto, Ayumi; Hattori, Yuki; Komori, Takaya [Laboratory of Cell Regulation, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan)] [Laboratory of Cell Regulation, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan); Nakamura, Takashi [Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan)] [Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Igarashi, Tatsuhiko, E-mail: tigarash@virus.kyoto-u.ac.jp [Laboratory of Primate Model, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan)] [Laboratory of Primate Model, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan); Harashima, Hideyoshi, E-mail: harasima@pharm.hokudai.ac.jp [Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan)] [Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Sugita, Masahiko, E-mail: msugita@virus.kyoto-u.ac.jp [Laboratory of Cell Regulation, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan)] [Laboratory of Cell Regulation, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan)

2013-11-08

416

Numeric and symbolic evaluation of the pfaffian of general skew-symmetric matrices  

NASA Astrophysics Data System (ADS)

Evaluation of pfaffians arises in a number of physics applications, and for some of them a direct method is preferable to using the determinantal formula. We discuss two methods for the numerical evaluation of pfaffians. The first is tridiagonalization based on Householder transformations. The main advantage of this method is its numerical stability that makes unnecessary the implementation of a pivoting strategy. The second method considered is based on Aitken's block diagonalization formula. It yields to a kind of LU (similar to Cholesky's factorization) decomposition (under congruence) of arbitrary skew-symmetric matrices that is well suited both for the numeric and symbolic evaluations of the pfaffian. Fortran subroutines (FORTRAN 77 and 90) implementing both methods are given. We also provide simple implementations in Python and Mathematica for purpose of testing, or for exploratory studies of methods that make use of pfaffians. Program summaryProgram title:PFAFFIAN Catalogue identifier: AEJD_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJD_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 2281 No. of bytes in distributed program, including test data, etc.: 13 226 Distribution format: tar.gz Programming language: Fortran 77 and 90 Computer: Any supporting a FORTRAN compiler Operating system: Any supporting a FORTRAN compiler RAM: a few MB Classification: 4.8 Nature of problem: Evaluation of the pfaffian of a skew symmetric matrix. Evaluation of pfaffians arises in a number of physics applications involving fermionic mean field wave functions and their overlaps. Solution method: Householder tridiagonalization. Aitken's block diagonalization formula. Additional comments: Python and Mathematica implementations are provided in the main body of the paper. Running time: Depends on the size of the matrices. For matrices with 100 rows and columns a few milliseconds are required.

González-Ballestero, C.; Robledo, L. M.; Bertsch, G. F.

2011-10-01

417

Analysis and Investigation of Skew Effect on Behavior and Performance of a Small Scale Three-Phase Self-Excited Induction Generator  

NASA Astrophysics Data System (ADS)

This paper presents analysis and investigation of the skew effect on behavior and performance of a three-phase, 220/380V, 8.7/5.0A, ?/Y connected, 4 poles, 2.2kW self-excited induction generator (SEIG) with different angles rotor skewing. A 2D finite element analysis (2D-FEA) is used to consider core loss, flux density and circuit parameters. Analysis of excitation capacitor values for the SEIG based on a steady-state equivalent circuit model including rotor skew effect is given. Skewed rotor slots with angle of 0° (non-skew), 5° and 10° for the SEIGs are employed. Testing and performance comparisons under steady-state operation with a pure resistive load have been conducted. Obtained results can be guidelines and recommendations for development of effective wind induction generators.

Sawetsakulanond, Budhapon; Kinnares, Vijit

418

General Analytical Solution for the Bending of Anisotropic Skew Plate with First-Order Shear Deformation Theory  

Microsoft Academic Search

A new systematic methodology for composite structures, a new type complex series methodology, is used to solve the bending problem of anisotropic skew plate using Ressiner first-order shear deformation theory. Using the geometric transformation, the governing differential equation and boundary conditions of the plate are transformed from the physical domain into a unit computational domain. Previously unavailable general analytical solutions

Zhang ChengZong

2003-01-01

419

Automatic data processing based on the skewness statistic parameter for subsurface defect detection by active infrared thermography  

Microsoft Academic Search

Non-destructive testing (NDT) by active infrared thermography requires of data processing techniques in order to: i. improve the thermal contrast between defective and non-defective areas, and ii. reduce the large quantity of images recorded during the inspection without losing relevant information. In this paper, the use of the skewness statistic parameter is proposed for the automatic processing of thermographic sequences

F. J. Madruga; C. Ibarra-Castanedo; O. M. Conde; J. M. López-Higuera; X. Maldague

420

Free Vibration of Skew Fiber-reinforced Composite and Sandwich Laminates using a Shear Deformable Finite Element Model  

Microsoft Academic Search

A simple Co isoparametric finite element model, based on a higher- order shear deformation theory is presented for the free vibration analysis of isotropic, orthotropic, and layered anisotropic composite and sandwich skew laminates. This theory incorporates a realistic nonlinear variation of displacements through the laminate thickness, and eliminates the use of shear correction coeffi- cients. The boundary conditions on the

AJAY KUMAR GARG; RAKESH KUMAR KHARE; TARUN KANT

2006-01-01

421

An integrated NTP-RTCP solution to audio skew detection and compensation for VoIP applications  

Microsoft Academic Search

The circuit switched POTS (plain old telephone system) preserves the timing relationship between media samples from sender to receiver through use of a common clock. For PC-based Internet multimedia, the existence of separate audio and system clocks on either end-host can introduce significant complications. Much work has taken place in recent years that addresses the issue of system clock skew

Hugh Melvin; Liam Murphy

2003-01-01

422

Lie algebras with triangular decompositions, non-skew-symmetric classical r-matrices and Gaudin-type integrable systems  

NASA Astrophysics Data System (ADS)

We consider the non-skew-symmetric g?g-valued classical r-matrices r12(u1,u2) with the spectral parameters possessing additional symmetries with respect to a finite-dimensional Lie subalgebra g0. Using them and the arbitrary (non-skew-symmetric) solution c12 of a modified Yang-Baxter equation on g0 we construct new classical non-skew-symmetric r-matrices r12c(u1,u2). We show that both types of r-matrices are connected to the Lie algebras with the "triangular" decomposition and re-obtain our result using the corresponding classical R-operators. We consider "twisted" loop Lie algebras as our main examples and explicitly obtain the corresponding r-matrices r12(u1,u2) and r12c(u1,u2). We use the constructed non-skew-symmetric classical r-matrices in order to produce mutually commuting quantum Gaudin-type hamiltonians.

Skrypnyk, T.

2010-03-01

423

Closed Busse balloon for rolls and skew-varicose instability in a Swift-Hohenberg model with nonlinear resonance  

NASA Astrophysics Data System (ADS)

A Swift-Hohenberg model incorporating a nonlinear resonance is shown to produce stable rolls only in a closed region of the parameter space. This Busse balloon is limited by zigzag and Eckhaus boundaries. A skew-varicose instability outside the balloon also exists. Implications with nonlinear optics and hydrodynamic convection are commented.

Sánchez-Morcillo, Víctor J.; de Valcárcel, Germán J.

1998-09-01

424

Effect of velocity profile skewing on blood velocity and volume flow waveforms derived from maximum Doppler spectral velocity.  

PubMed

Given evidence that fully developed axisymmetric flow may be the exception rather than the rule, even in nominally straight arteries, maximum velocity (V(max)) can lie outside the Doppler sample volume (SV). The link between V(max) and derived quantities, such as volume flow (Q), may therefore be more complex than commonly thought. We performed idealized virtual Doppler ultrasound on data from image-based computational fluid dynamics (CFD) models of the normal human carotid artery and investigated how velocity profile skewing and choice of sample volume affected V(max) waveforms and derived Q variables, considering common assumptions about velocity profile shape (i.e., Poiseuille or Womersley). Severe velocity profile skewing caused substantial errors in V(max) waveforms when using a small, centered SV, although peak V(max) was reliably detected; errors with a long SV covering the vessel diameter were orientation dependent but lower overall. Cycle-averaged Q calculated from V(max) was typically within ±15%, although substantial skewing and use of a small SV caused 10%-25% underestimation. Peak Q derived from Womersley's theory was generally accurate to within ±10%. V(max) pulsatility and resistance indexes differed from Q-based values, although the Q-based resistance index could be predicted reliably. Skewing introduced significant error into V(max)-derived Q waveforms, particularly during mid-to-late systole. Our findings suggest that errors in the V(max) and Q waveforms related to velocity profile skewing and use of a small SV, or orientation-dependent errors for a long SV, could limit their use in wave analysis or for constructing characteristic or patient-specific flow boundary conditions for model studies. PMID:23453373

Mynard, Jonathan P; Steinman, David A

2013-05-01

425

Myocardial bridges: morphological and functional aspects  

Microsoft Academic Search

OBJECTIVE--To assess the arrangement of myocardial bridges. DESIGN--A necropsy study of 90 consecutive hearts (56 male, 34 female). RESULTS--Myocardial bridges, either single or multiple, were seen in 50 (55.6%) of the 90 hearts. The left anterior descending artery was the most commonly affected artery. Thirty five of the 50 hearts which contained in total 41 muscle bridges were dissected further

A G Ferreira; S E Trotter; B König; L V Décourt; K Fox; E G Olsen

1991-01-01

426

Resin bonded bridges: techniques for success.  

PubMed

Resin bonded bridges are a minimally invasive option for replacing missing teeth. Although they were first described over 30 years ago, evidence regarding their longevity remains limited and these restorations have developed an undeserved reputation for failure. This article provides a brief review of the literature regarding bridge success and continues to highlight aspects of case selection, bridge design and clinical procedure which may improve outcome. PMID:21836574

Durey, K A; Nixon, P J; Robinson, S; Chan, M F W-Y

2011-08-01

427

Electrical transmission of molecular bridges  

NASA Astrophysics Data System (ADS)

Transmission of electrons through orbitals of molecules is discussed using high-level ab initio methods that allow an orbital interpretation. The transmission is computed for a molecule tethered between gold atoms. Strong coupling to the gold is achieved using a sulfur atom at each end of the molecule. ?-type orbitals can conduct as well as conjugated bridges provided that the orbitals have weights on the sulfur atoms. The current depends exponentially on the voltage applied to the molecule and this voltage can also shift the electronic density and further alter the transmission. The conductivity can also be modified by a gate voltage.

Remacle, F.; Levine, R. D.

2004-01-01

428

Level II scour analysis for Bridge 10 (NORWTH00120010) Town Highway 012 Bloody Brook, Norwich, Vermont  

USGS Publications Warehouse

This report provides the results of a detailed Level II analysis of scour potential at structure NORWTH00120010 on town highway 12 crossing Bloody Brook, Norwich, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge, available from VTAOT files, was compiled prior to conducting the Level I and Level II analyses and can be found in Appendix D. The site is in the New England Upland physiographic province in east-central Vermont. The 8.98-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the left bank upstream and the left and right banks downstream are forested. The immediate right bank upstream is covered by shrub and brush with pasture on the overbank. Town Highway 12 runs along the valley of Bloody Brook; however, at structure NORWTH00120010 the road crosses Bloody Brook at a 90-degree angle. In the study area, Bloody Brook has a sinuous channel with a slope of approximately 0.014 ft/ft, an average channel top width of 41 ft and an average channel depth of 3 ft. The predominant channel bed materials are gravel and cobble (D50 is 51.0 mm or 0.167 ft). The geomorphic assessment at the time of the Level I site visit on October 31, 1994, indicated that the reach was unstable. The town highway 12 crossing of Bloody Brook is a 34-ft-long, two-lane bridge consisting of one 30-foot clear span (Vermont Agency of Transportation, written commun., July 29, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. The right abutment is protected by sparse type-2 stone fill (less than 24 inches diameter). The channel is skewed 0 degrees to the opening and the opening-skew-to-roadway is 0 degrees. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

Ayotte, Joseph D.

1996-01-01

429

3. CONTEXTUAL VIEW OF BRIDGE IN SETTING, LOOKING SOUTHWEST FROM ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. CONTEXTUAL VIEW OF BRIDGE IN SETTING, LOOKING SOUTHWEST FROM ELEVATED GRADE OF EUREKA SOUTHERN RAILROAD. EUREKA SOUTHERN TRUSS BRIDGE AT EXTREME LEFT, 1924 HIGHWAY BRIDGE IN CENTER, 1952 HIGHWAY BRIDGE AT RIGHT - Van Duzen River Bridge, Spanning Van Duzen River at CA State Highway 101, Alton, Humboldt County, CA

430

Monitoring fatigue life in concrete bridge deck slabs  

Microsoft Academic Search

Concrete bridge deck slabs are the most common form of bridge deck construction in short and medium span bridge structures in North America. Understanding and monitoring the condition of these bridge decks is an important component of a bridge management strategy. Progressive deterioration due to fatigue occurs in concrete decks due to the large number of cycles of heavy wheels

J. Newhook; V. Limaye

2007-01-01

431

11. Photocopy of photograph, c. 1900. VIEW OF BRIDGE STREET ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Photocopy of photograph, c. 1900. VIEW OF BRIDGE STREET BRIDGE NEAR FLOOD STAGE, LOOKING NORTHEAST. (Original in Union City Historical Museum.) 8'x10' enlargement from 4'x5' negative. - Bridge Street Bridge, Spanning Little French Creek at Bridge Street, Union City, Erie County, PA

432

Monitoring system of arch bridge for safety network management  

Microsoft Academic Search

Korea has constructed the safety management network monitoring test systems for the civil infrastructure since 2006 which includes airport structure, irrigation structure, railroad structure, road structure, and underground structure. Bridges among the road structure include the various superstructure types which are Steel box girder bridge, suspension bridge, PSC-box-girder bridge, and arch bridge. This paper shows the process of constructing the

Bong Chul Joo; Young Jun Yoo; Chin Hyung Lee; Ki Tae Park; Yoon Koog Hwang

2010-01-01

433

6. VIEW OF GDOT BRIDGE NO. 02700268X00678N BRIDGE PLATE IDENTIFYING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. VIEW OF GDOT BRIDGE NO. 027-00268X-00678N BRIDGE PLATE IDENTIFYING COUNTY COMMISSIONERS AT THE TIME OF CONSTRUCTION. - GDOT Bridge No. 027-00268X-00678N, County Road 268-Empress Road span Piscola Creek, Quitman, Brooks County, GA

434

Bridge over little Pine Creek (S.R. 1026, section 002 bridge) ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Bridge over little Pine Creek (S.R. 1026, section 002 bridge) looking west across traffic level - Bridge over Little Pine Creek, State Route 1026 over Little Pine Creek, 2.01 kilometers (1.25 miles) East of Bendertown, Jonestown, Columbia County, PA

435

Bridge over little Pine Creek (S.R. 1026, section 002 bridge) ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Bridge over little Pine Creek (S.R. 1026, section 002 bridge) looking north-northeast across traffic level - Bridge over Little Pine Creek, State Route 1026 over Little Pine Creek, 2.01 kilometers (1.25 miles) East of Bendertown, Jonestown, Columbia County, PA

436

FBG bending gauge on bridges: an effort towards standardization of bridge structural health monitoring  

Microsoft Academic Search

The FBG bending gauge developed by POFC is applied in several situations involving bridge safety\\/health monitoring. Under static loading conditions, the FBG bending gauge serves as an excellent tool to deduce an overall deflection curve on the bridge section under study. The gauge also works well in dynamic situations where instantaneous vertical deflections of bridge structures resulting from a cruising

I.-Wen Wu; Chung-Yue Wang; Ming-Hung Chen; Hao-Lin Wang; Allen Cheng; Patrick Tsai; David Wu; Hung-Wei ChangChien; Hentai Shang

2007-01-01

437

Bridges to sustainable tropical health  

PubMed Central

Ensuring sustainable health in the tropics will require bridge building between communities that currently have a limited track record of interaction. It will also require new organizational innovation if much of the negative health consequences of large-scale economic development projects are to be equitably mitigated, if not prevented. We focus attention on three specific contexts: (i) forging linkages between the engineering and health communities to implement clean water and sanitation on a broad scale to prevent reworming, after the current deworming-only programs, of people by diverse intestinal parasites; (ii) building integrated human and animal disease surveillance infrastructure and technical capacity in tropical countries on the reporting and scientific evidence requirements of the sanitary and phytosanitary agreement under the World Trade Organization; and (iii) developing an independent and equitable organizational structure for health impact assessments as well as monitoring and mitigation of health consequences of economic development projects. Effective global disease surveillance and timely early warning of new outbreaks will require a far closer integration of veterinary and human medicine than heretofore. Many of the necessary surveillance components exist within separate animal- and human-oriented organizations. The challenge is to build the necessary bridges between them.

Singer, Burton H.; de Castro, Marcia Caldas

2007-01-01

438

Capacitance bridge measurements of magnetostriction  

NASA Astrophysics Data System (ADS)

Magnetostriction effects were investigated for three different materials by using a simple, reproducible, and cost-effective method recently developed in our laboratory. The magnetostriction effects were generated by a large oscillating magnetic field produced by a high current 60 Hz ac welder power supply, capable of reaching saturation levels for the material, and then detected by a change in capacitance between a hollow cylindrical sample and a concentric brass ring. This capacitance change was continuously monitored at a high frequency rate by a standard laboratory capacitance bridge meter. The output voltage of the bridge was fed into a storage cathode-ray oscilloscope and its voltage versus time signals were then analyzed by a computer program. Two ferromagnetic rings, constructed of high-speed steels 4620 and 4340, which have proven applicability for use in magnetoelastic torque sensing, were used as the samples for investigating the magnetostriction effects, while a paramagnetic aluminum ring was used for the control sample. Our study showed that the 4340 ring, which had higher nickel, cobalt, and chromium content than that of the 4620 ring, had the largest magnetostriction effect, and that the aluminum ring displayed no magnetostriction effect, as was expected. We have found this experimental method to be both reproducible and sufficient to rank different ferromagnetic materials by their magnetostriction level, which is a significant consideration in producing effective magnetoelastic torque sensors.

Boley, Mark S.; Shin, Won C.; Rigsbee, David K.; Franklin, Doug A.

2002-05-01

439

Bridge coupled drift tube linacs  

SciTech Connect

Modern linac designs for treating radioactive waste achieve high proton currents through funneling at low energy, typically around 20 MeV. The resulting switch to a high-frequency accelerating structure poses severe performance and fabrication difficulties below 100 MeV. Above 100 MeV. proven coupled-cavity linacs (CCLS) am available. However, at 20 MeV one must choose between a high-frequency drift-tube linac (DTL) or a coupled-cavity linac with very short cells. Potential radiation damage from the CW beam, excessive RF power losses, multipactoring, and fabricability all enter into this decision. At Los Alamos, we have developed designs for a bridge-coupled DTL (BCDTL) that. like a CCL, uses lattice focusing elements and bridge couplers, but that unlike a CCL, accelerates the beam in simple. short, large-aperture DTL modules with no internal quadrupole focusing. Thus, the BCDTL consumes less power than the CCL linac without degrading beam performance and is simpler and cheaper to fabricate in the 20 to 100 MeV range.

Liska, D.; Smith, P.; Carlisle, L.; Larkin, T.

1992-12-01

440

Bridge coupled drift tube linacs  

SciTech Connect

Modern linac designs for treating radioactive waste achieve high proton currents through funneling at low energy, typically around 20 MeV. The resulting switch to a high-frequency accelerating structure poses severe performance and fabrication difficulties below 100 MeV. Above 100 MeV. proven coupled-cavity linacs (CCLS) am available. However, at 20 MeV one must choose between a high-frequency drift-tube linac (DTL) or a coupled-cavity linac with very short cells. Potential radiation damage from the CW beam, excessive RF power losses, multipactoring, and fabricability all enter into this decision. At Los Alamos, we have developed designs for a bridge-coupled DTL (BCDTL) that. like a CCL, uses lattice focusing elements and bridge couplers, but that unlike a CCL, accelerates the beam in simple. short, large-aperture DTL modules with no internal quadrupole focusing. Thus, the BCDTL consumes less power than the CCL linac without degrading beam performance and is simpler and cheaper to fabricate in the 20 to 100 MeV range.

Liska, D.; Smith, P.; Carlisle, L.; Larkin, T.

1992-01-01

441

Salt-bridge energetics in halophilic proteins.  

PubMed

Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are -3.0 kcal mol-1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of -5.0 kcal mol-1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (-10 kcal mol-1) exceeds than that of bridge term (-7 kcal mol-1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic signature in its specific electrostatic interactions which we hope would help in protein engineering and bioinformatics studies. PMID:24743799

Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K

2014-01-01

442

Salt-Bridge Energetics in Halophilic Proteins  

PubMed Central

Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are ?3.0 kcal mol?1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of ?5.0 kcal mol?1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (?10 kcal mol?1) exceeds than that of bridge term (?7 kcal mol?1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic signature in its specific electrostatic interactions which we hope would help in protein engineering and bioinformatics studies.

Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K.

2014-01-01

443

Segregation of a totally skewed pattern of X chromosome inactivation in four familial cases of Rett syndrome without MECP2 mutation: implications for the disease  

PubMed Central

BACKGROUND—Rett syndrome is a neurodevelopmental disorder affecting only girls; 99.5% of Rett syndrome cases are sporadic, although several familial cases have been reported. Mutations in the MECP2 gene were identified in approximately 70-80% of sporadic Rett syndrome cases.?METHODS—We have screened the MECP2 gene coding region for mutations in five familial cases of Rett syndrome and studied the patterns of X chromosome inactivation (XCI) in each girl.?RESULTS—We found a mutation in MECP2 in only one family. In the four families without mutation in MECP2, we found that (1) all mothers exhibit a totally skewed pattern of XCI; (2) six out of eight affected girls also have a totally skewed pattern of XCI; and (3) it is the paternally inherited X chromosome which is active in the patients with a skewed pattern of XCI. Given that the skewing of XCI is inherited in our families, we genotyped the whole X chromosome using 32 polymorphic markers and we show that a locus potentially responsible for the skewed XCI in these families could be located on the short arm of the X chromosome.?CONCLUSION—These data led us to propose a model for familial Rett syndrome transmission in which two traits are inherited, an X linked locus abnormally escaping X chromosome inactivation and the presence of a skewed XCI in carrier women.???Keywords: Rett syndrome; skewed X chromosome inactivation; X chromosome; MECP2

Villard, L.; Levy, N.; Xiang, F.; Kpebe, A.; Labelle, V.; Chevillard, C.; Zhang, Z.; Schwartz, C.; Tardieu, M.; Chelly, J.; Anvret, M.; Fontes, M.

2001-01-01

444

NPIP: A skew line needle configuration optimization system for HDR brachytherapy  

SciTech Connect

Purpose: In this study, the authors introduce skew line needle configurations for high dose rate (HDR) brachytherapy and needle planning by integer program (NPIP), a computational method for generating these configurations. NPIP generates needle configurations that are specific to the anatomy of the patient, avoid critical structures near the penile bulb and other healthy structures, and avoid needle collisions inside the body. Methods: NPIP consisted of three major components: a method for generating a set of candidate needles, a needle selection component that chose a candidate needle subset to be inserted, and a dose planner for verifying that the final needle configuration could meet dose objectives. NPIP was used to compute needle configurations for prostate cancer data sets from patients previously treated at our clinic. NPIP took two user-parameters: a number of candidate needles, and needle coverage radius, {delta}. The candidate needle set consisted of 5000 needles, and a range of {delta} values was used to compute different needle configurations for each patient. Dose plans were computed for each needle configuration. The number of needles generated and dosimetry were analyzed and compared to the physician implant. Results: NPIP computed at least one needle configuration for every patient that met dose objectives, avoided healthy structures and needle collisions, and used as many or fewer needles than standard practice. These needle configurations corresponded to a narrow range of {delta} values, which could be used as default values if this system is used in practice. The average end-to-end runtime for this implementation of NPIP was 286 s, but there was a wide variation from case to case. Conclusions: The authors have shown that NPIP can automatically generate skew line needle configurations with the aforementioned properties, and that given the correct input parameters, NPIP can generate needle configurations which meet dose objectives and use as many or fewer needles than the current HDR brachytherapy workflow. Combined with robot assisted brachytherapy, this system has the potential to reduce side effects associated with treatment. A physical trial should be done to test the implant feasibility of NPIP needle configurations.

Siauw, Timmy; Cunha, Adam; Berenson, Dmitry; Atamtuerk, Alper; Hsu, I-Chow; Goldberg, Ken; Pouliot, Jean [Department of Civil and Environmental Engineering, University of California, Berkeley, 760 Davis Hall, Berkeley, California 94720-1710 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4th Floor Sutardja Dai Hall, Berkeley, California 94720-1764 (United States); Department of Industrial Engineering and Operations, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Industrial Engineering and Operations Research and Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States)

2012-07-15

445

Foam Bridging for Surf Zone Breaching Operations.  

National Technical Information Service (NTIS)

The goal of this project is to demonstrate the potential of rigid polyurethane foam (RPF) as a building material to allow building of bridges for transport of heavy material and troops over an obstacle and mine field. In the future such a bridge could be ...

J. Webster R. Ledman R. Woodfin

1998-01-01

446

Monorail bridge conveyor. Phase II report  

Microsoft Academic Search

This report covers the second phase of a four-phase contract to develop and test a roof hung monorail bridge conveyor coal haulage system working behind a continuous miner. Phase II covers the fabrication and assembly of all the components in making up the Monoral Bridge Conveyor System. The original concept presented had to be analyzed before final design could proceed.

Gonski

1982-01-01

447

Teaching Elements and Principles of Bridge Design  

ERIC Educational Resources Information Center

Bridge construction is a popular classroom activity. However, the basic principles of tension, compression, and counterbalance are not always clearly represented and defined. The common materials used to construct model bridges, such as straws, toothpicks, Legos[TM], and building blocks, are often too flexible or stationary to demonstrate the…

Beck, Charles

2005-01-01

448

Investigations of a Precast Bridge Deck System.  

National Technical Information Service (NTIS)

Improved methods of bridge deck construction are greatly needed. Bridge decks are often the first element to require repair or replacement because of its direct exposure to the elements and tire wear. This report presents a new precast overhang system tha...

M. Ghashgesh S. Patil T. Ley

2010-01-01

449

A bridging model for parallel computation  

Microsoft Academic Search

The success of the von Neumann model of sequential computation is attributable to the fact that it is an efficient bridge between software and hardware: high-level languages can be efficiently compiled on to this model; yet it can be effeciently implemented in hardware. The author argues that an analogous bridge between software and hardware in required for parallel computation if

Leslie G. Valiant

1990-01-01

450

Bridge health monitoring using wavelet analysis  

Microsoft Academic Search

Bridge health monitoring is defined as the continuous monitoring of a bridge's state properties such as static and dynamic response in order to diagnose the onset of anomalous structural behavior. This involves measuring and evaluating the state properties and relating these to defined performance parameters. The process of measuring state properties, either continuously or periodically, produces large amounts of data.

Pilate Moyo; James M. Brownjohn

2001-01-01

451

Automatic Microcircuit Bridge and Autobalancing Unit.  

National Technical Information Service (NTIS)

This report summarizes the design and test of a Microcricuit Bridge and Balancing Unit to be used in a precision measurement of quartz crystal resonators. Design goals for the Bridge and Balancing Unit were to measure resistance with a 5% accuracy and cap...

W. F. Byers R. J. Hanson W. J. Riley

1979-01-01

452

Paul Dirac:. Building Bridges of the Mind  

NASA Astrophysics Data System (ADS)

Paul Dirac was a brilliant and original thinker. He used his physical intuition and his ideal of mathematical beauty to construct bridges between major areas of physics. This article discusses several such important works, including the bridge between quantum mechanics and relativity that led to his prediction of the existence of antimatter.

Brown, Laurie M.

2003-12-01

453

Anatomy of Bridge Flutter: Some New Insights  

Microsoft Academic Search

A new analysis framework that offers direct and explicit expressions for estimating the bimodal coupled flutter is presented. Its accuracy and effectiveness are demonstrated through a flutter analysis of a cable -stayed bridge. This framew ork is utilized to emphasize significance of the role played by both structural dynamics and aerodynamics on bridge flutter, which helps in better tailoring of

Xinzhong Chen; Ahsan Kareem

454

Health monitoring of FRP bridge decks  

Microsoft Academic Search

Statistics released in the fall 1989 show that 238,357 (41%) of the nation's 577,710 bridges are either structurally deficient or functionally obsolete. New materials are being explored for use in bridge systems to solve this problem. These materials are less affected by corrosive environmental conditions than conventional civil engineering materials and thus, require less maintenance and potentially provide a longer

Marybeth Miceli; Michael R. Horne; John C. Duke

2001-01-01

455

Family of Prepackaged Pipeline Suspension Bridges.  

National Technical Information Service (NTIS)

The U.S. Army Mobility Equipment Research and Development Command (MERADCOM) has designed 400-foot, 200-foot, and 100-foot pipeline suspension bridges and constructed and tested the 100-ft version. The suspension bridges come in kit form. The kit contains...

K. Solinsky

1976-01-01

456

Semiconductor bridge (SCB) research and development.  

National Technical Information Service (NTIS)

Sandia National Laboratories has developed a semiconductor bridge (SCB) igniter for the ignition of a variety of explosive materials. When subjected to a low-energy current pulse, the bridge bursts into a plasma causing rapid ignition of the explosive mat...

R. W. Bickes C. B. McCampbell

1991-01-01

457

Design of Highway Bridges for Extreme Events.  

National Technical Information Service (NTIS)

The Design of Highway Bridges for Extreme Events is a design procedure for the application of extreme load events and the combination of their load effects in the AASHTO LRFD Bridge Design Specifications (1998). This is achieved by proposing a set of load...

2003-01-01

458

A long range full bandwidth Ethernet bridge  

SciTech Connect

An Ethernet Bridge has been built which has both a range which exceeds 39 kilometers and a full bandwidth of 10 Mbaud. The bridge is transparent to all Ethernet packets and is suitable for distant system control, distant high speed data collection and for all normal Ethernet use.

Thompson, M.A.; Lackey, J.L.; Nissen, K.H.; Thielman, D.J.; Hiulian, Z. (Physical Sciences Lab., Univ. of Wisconsin - Madison, 3725 Schneider Dr., Stoughton, WI (US))

1988-02-01

459

Engaging Faculty for Innovative STEM Bridge Programs  

ERIC Educational Resources Information Center

Bridge programs, in which underprepared students gain the academic and technical skills necessary for college level courses and entry-level employment, are a promising initiative for expanding access to, and success in, community college education. For career pathways related to science, technology, engineering, or mathematics (STEM), bridge

Goldfien, Andrea C.; Badway, Norena Norton

2014-01-01

460

Innovations in Glulam Timber Bridge Design  

Microsoft Academic Search

3 , Non-Member Abstract Structural glued laminated timber has been successfully used as a bridge material in the United States for more than 50 years. Until the late 1980s, the majority of these bridges were conventional girder or deck superstructures manufactured from softwood lumber species. Recently, applications employing glued laminated timber have been expanded to include alternative wood species and

Michael A. Ritter; Thomas G. Williamson; Russell C. Moody

461

Mormon Creek Bridge: Performance After Three Years.  

National Technical Information Service (NTIS)

The Mormon Creek Bridge is an experimental parallel-chord, stress-laminated deck design. It is the first of its kind and has been in service for more than 3 years. The structural performance and experimental features of the bridge have been monitored cont...

W. J. McCutcheon

1992-01-01

462

Build and Test a Paper Bridge  

NSDL National Science Digital Library

In this hands-on activity, learners make a bridge out of a folded piece of paper and two blocks. Then they test their structure by stacking coins (and other things) on it, discovering how much weight the bridge can support before it collapses. This activity explores engineering, technology, architecture, weight, compression, tension, and balance.

Science, New Y.

1999-01-01

463

Instrumentation for load rating of bridges  

NASA Astrophysics Data System (ADS)

A large percentage of the nation's bridges are classified as structurally deficient or functionally obsolete. Many bridges are classified as such due to the bridge's load rating. However, the vast majority of bridges are not actually tested to determine their load capacity. In general, actually testing a structure to determine the load rating is time consuming and expensive. As a result only a low number of bridges can be tested. A main time consuming portion of the load test is the setup of conventional instrumentation to monitor the status of the bridge under test. Typically strain gages and LVDT (or similar) deflection transducers are used. Instrumentation which would allow rapid load testing of bridges is currently being developed and tested at the Federal Highway Administration. This instrumentation includes wireless data acquisition systems interfaced with clamp-on strain gages, which can be placed at a measurement location in a matter of minutes. Also, the instrumentation includes a remote laser- based deflection measurement system. The combination of the two types of instrumentation, wireless data acquisition and laser-based deflection measurements, has the potential to allow a greater number of structures to be load rated giving a more accurate picture of the health of the nation's bridges.

Fuchs, P. A.; Chase, Steven B.

1998-03-01

464

Effect of modal damping on bridge aeroelasticity  

Microsoft Academic Search

Estimation of modal damping is always a critical first step in the analytical estimation of the flutter and buffeting reponses of long-span suspended bridges. The impact of under or over estimation of modal damping on the aerodynamic and aeroelastic behavior of suspended bridges is not clear. This issue surfaced when a seismic retrofit of the Golden Gate birdge using viscous

Anurag Jain; Nicholas P. Jones; Robert H. Scanlan

1998-01-01

465

Bridge stresses and design in IPM machines  

Microsoft Academic Search

This document describes the stresses in the bridges of three types of interior permanent magnet (IPM) machines. These are machines which had a V-magnet slot, machines which have a straight slot, in machines which have a V configuration with a center post. Formulae for calculating the bridge stresses are included for the straight and V shaped slots. The formulae are

Ron D Bremner

2009-01-01

466

12. Interior detail of bridge operator's house showing generator and ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Interior detail of bridge operator's house showing generator and bridge operator, Mr. Gene Amonette, facing west. - Palm Valley Bridge, County Road 210 spanning Intracoastal Waterway, Ponte Vedra Beach, St. Johns County, FL

467

7. VIEW ACROSS BRIDGE FROM NORTHWEST CORNER WITH WIDE ANGLE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. VIEW ACROSS BRIDGE FROM NORTHWEST CORNER WITH WIDE ANGLE LENS SHOWING BRIDGE IN LANDSCAPE. - Wildcat Creek Bridge, Spanning Wildcat Creek on New Big Oak Flat Road, Yosemite Village, Mariposa County, CA

468

18. VIEW OF STEEL ARCH, SHOWING DETAILS OF BRIDGE DECK ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. VIEW OF STEEL ARCH, SHOWING DETAILS OF BRIDGE DECK (IRVING DECK), LATERAL BRACING, HANGERS AND STEEL ARCH RIBS OF NORTH CHORD, LOOKING NORTHWEST - Notre Dame Bridge, Spanning Merrimack River on Bridge Street, Manchester, Hillsborough County, NH

469

46 CFR 92.03-1 - Navigation bridge visibility.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Navigation bridge visibility. 92.03-1 Section...CARGO AND MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Navigation Bridge Visibility § 92.03-1 Navigation bridge visibility. Each cargo...

2010-10-01

470

46 CFR 92.03-1 - Navigation bridge visibility.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Navigation bridge visibility. 92.03-1 Section...CARGO AND MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Navigation Bridge Visibility § 92.03-1 Navigation bridge visibility. Each cargo...

2009-10-01

471

46 CFR 72.04-1 - Navigation bridge visibility.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Navigation bridge visibility. 72.04-1 Section...CONTINUED) PASSENGER VESSELS CONSTRUCTION AND ARRANGEMENT Navigation Bridge Visibility § 72.04-1 Navigation bridge visibility. Each...

2010-10-01

472

46 CFR 190.02-1 - Navigation bridge visibility.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Navigation bridge visibility. 190.02-1 Section...OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Navigation Bridge Visibility § 190.02-1 Navigation bridge visibility. Each...

2010-10-01

473

46 CFR 72.04-1 - Navigation bridge visibility.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Navigation bridge visibility. 72.04-1 Section...CONTINUED) PASSENGER VESSELS CONSTRUCTION AND ARRANGEMENT Navigation Bridge Visibility § 72.04-1 Navigation bridge visibility. Each...

2009-10-01

474

46 CFR 190.02-1 - Navigation bridge visibility.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Navigation bridge visibility. 190.02-1 Section...OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Navigation Bridge Visibility § 190.02-1 Navigation bridge visibility. Each...

2009-10-01

475

21 CFR 872.3770 - Temporary crown and bridge resin.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Temporary crown and bridge resin. 872.3770 Section 872.3770 Food...872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a...

2010-04-01

476

21 CFR 872.3770 - Temporary crown and bridge resin.  

...2014-04-01 false Temporary crown and bridge resin. 872.3770 Section 872.3770 Food...872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a...

2014-04-01

477

21 CFR 872.3770 - Temporary crown and bridge resin.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Temporary crown and bridge resin. 872.3770 Section 872.3770 Food...872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a...

2012-04-01

478

21 CFR 872.3770 - Temporary crown and bridge resin.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Temporary crown and bridge resin. 872.3770 Section 872.3770 Food...872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a...

2011-04-01

479

11. Standing on westerly fender at edge of bridge looking ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Standing on westerly fender at edge of bridge looking easterly, showing horizontal beams for deck and cross beams (reflection of steel grating on deck). Also shows bridge guardrail. - Colusa Bridge, Spanning Sacramento River, Colusa, Colusa County, CA

480

49 CFR 237.31 - Adoption of bridge management programs.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Adoption of bridge management programs. 237.31 Section 237...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Railroad Bridge Safety Assurance § 237.31 Adoption of...

2013-10-01

481

49 CFR 237.101 - Scheduling of bridge inspections.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Scheduling of bridge inspections. 237.101 Section 237.101 ...RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.101 Scheduling of...

2013-10-01

482

33 CFR 115.50 - Application for bridge permits.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Application for bridge permits. 115.50 Section 115.50 Navigation...Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE...

2010-07-01

483

49 CFR 237.55 - Railroad bridge supervisors.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Railroad bridge supervisors. 237.55 Section 237...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Qualifications and...Responsible Persons § 237.55 Railroad bridge supervisors. A railroad...

2013-10-01

484

46 CFR 112.43-7 - Navigating bridge distribution panel.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Navigating bridge distribution panel. 112.43-7 ...Systems § 112.43-7 Navigating bridge distribution panel. (a) Except...a distribution panel on the navigating bridge: (1) Navigation lights not...

2013-10-01

485

23 CFR 650.809 - Movable span bridges.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Movable span bridges. 650.809 Section 650.809 Highways... ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span...

2013-04-01

486

23 CFR 650.409 - Evaluation of bridge inventory.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Evaluation of bridge inventory. 650.409 Section 650.409...TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program...

2013-04-01

487

33 CFR 115.70 - Advance approval of bridges.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Advance approval of bridges. 115.70 Section 115.70 Navigation and Navigable...Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE...

2013-07-01

488

23 CFR 650.307 - Bridge inspection organization.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Bridge inspection organization. 650.307 Section...TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS National Bridge Inspection Standards § 650.307...

2013-04-01

489

49 CFR 237.51 - Railroad bridge engineers.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Railroad bridge engineers. 237.51 Section 237...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Qualifications and...Responsible Persons § 237.51 Railroad bridge engineers. (a) A railroad...

2013-10-01

490

49 CFR 236.766 - Locking, movable bridge.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Locking, movable bridge. 236.766 Section 236.766 Transportation... Definitions § 236.766 Locking, movable bridge. The rail locks, bridge locks, bolt locks, circuit controllers,...

2013-10-01

491

23 CFR 650.705 - Application for discretionary bridge funds.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Application for discretionary bridge funds. 650.705 Section 650.705...TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650.705...

2013-04-01

492

33 CFR 115.50 - Application for bridge permits.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Application for bridge permits. 115.50 Section 115.50 Navigation...Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE...

2009-07-01

493

25 CFR 170.507 - Who reviews bridge inspection reports?  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Who reviews bridge inspection reports? 170.507 Section...Indian Reservation Roads Program Facilities Bridge Inspection § 170.507 Who reviews bridge inspection reports? The person...

2013-04-01

494

49 CFR 237.33 - Content of bridge management programs.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Content of bridge management programs. 237.33 Section 237...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Railroad Bridge Safety Assurance § 237.33 Content of...

2013-10-01

495

Elevation, west portal. Sign on portal reads Watson Mill Bridge, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Elevation, west portal. Sign on portal reads Watson Mill Bridge, est. 1885. - Watson Mill Bridge, Spanning South Fork Broad River, Watson Mill Road, Watson Mill Bridge State Park, Comer, Madison County, GA

496

11. OLD BRIDGE AND ROADBED NEAR NORTH FORK VIRGIN RIVER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. OLD BRIDGE AND ROADBED NEAR NORTH FORK VIRGIN RIVER BRIDGE, FACING NORTH - Zion-Mount Carmel Highway, Virgin River Bridge, Spanning North Fork of Virgin River on Zion-Mount Carmel Highway, Springdale, Washington County, UT

497

12. PLANK BRIDGE ON OLD ROAD NEAR NORTH FORK VIRGIN ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. PLANK BRIDGE ON OLD ROAD NEAR NORTH FORK VIRGIN RIVER BRIDGE, FACING EAST - Zion-Mount Carmel Highway, Virgin River Bridge, Spanning North Fork of Virgin River on Zion-Mount Carmel Highway, Springdale, Washington County, UT

498

21. c, 1915 Historic plan, standard 2 beam girder bridge. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. c, 1915 Historic plan, standard 2 beam girder bridge. United Construction Company, Albany, New York. Generic plan typical of Prescott Bridge. Source: New Hampshire Department of Transportation - Prescott Bridge, Spanning Lamprey River on Prescott Road, Raymond, Rockingham County, NH

499

6. EARLY MORNING VIEW OF BOTH JOSO HIGH BRIDGE (UNION ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. EARLY MORNING VIEW OF BOTH JOSO HIGH BRIDGE (UNION PACIFIC RAILROAD) IN BACKGROUND AND LYONS FERRY BRIDGE IN THE FOREGROUND - Snake River Bridge at Lyons' Ferry, State Route 261 spanning Snake River, Starbuck, Columbia County, WA

500

24. Photocopy of drawing, Draw for L Street Bridge, Sheet ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. Photocopy of drawing, Draw for L Street Bridge, Sheet 2: Floor Beams, July 1982. City of Boston Public Works Department Bridge files. - Summer Street Bridge, Spanning Reserved Channel, Boston, Suffolk County, MA