WorldWideScience
1

Particle-Gas Dynamics and Primary Accretion - Space Science and ...  

Science.gov (United States)

the revealed stage of T Tauri star evolution, is only a mere shadow of its former self. Once primary accretion starts, one has the (poorly quantified) ...

2

Scatter measurements for optical cone-beam computed tomography  

Energy Technology Data Exchange (ETDEWEB)

Both x-ray and optical cone-beam CT (CBCT) scanners are limited by scattered photons that contaminate the primary images. Transparent radiochromic gels and plastics are anticipated to produce less scattering than polymerization gels and hence result in reconstructed dose distributions with greater contrast and dynamic range. Four methods of scatter measurement were investigated to quantify scatter fractions using an in-house optical CBCT scanner. The methods consisted of generating either 'coin' shadows or primary beamlets in transmission images. The four methods generated similar results of 10% scatter fractions in gel transmission images for this particular scanner configuration with both leuco crystal violet and carbon black micelle gels. The scatter contributions were distributed as 5% from micelle gel, 2% from Teflon wall, 2% from refractive index matching liquid and 1% other sources. Applying a ...

2009-05-01

3

Towards an understanding of the light scalar mesons  

Energy Technology Data Exchange (ETDEWEB)

Although studied for many years the nature of the light scalar mesons remains controversial. Here we shall present a method, applicable for s-wave states located close to a threshold, that allows one to quantify the molecular part of a given state. When applied to the f{sub 0}(980) a dominance of the molecular component is found. In the second part, we show that requirements of field-theoretic consistency and chiral symmetry, when applied to the scattering of light pseudo-scalars, naturally lead to the appearance of dynamical poles in the scalar sector. A program is proposed on how to further investigate experimentally the mixing between these dynamical states and possible genuine quark states. (orig.)

2007-03-15

4

Test API: Interface DataAccessBean  

Science.gov (United States)

The DataAccessBean is similar to the Data Access Object (DAO) interface in that the DataAccessBean interface is meant to encapsulate the implementation details of the DynamicJavaBean that accesses persistent storage devices such as RDBMS, flat text file databases, etc.

5

Dynamic User-Defined Similarity Searching in Semi-Structured Text Retrieval  

CERN Document Server

Modern text retrieval systems often provide a similarity search utility, that allows the user to find efficiently a fixed number k of documents in the data set that are most similar to a given query (here a query is either a simple sequence of keywords or the identifier of a full document found in previous searches that is considered of interest). We consider the case of a textual database made of semi-structured documents. Each field, in turns, is modelled with a specific vector space. The problem is more complex when we also allow each such vector space to have an associated user-defined dynamic weight that influences its contribution to the overall dynamic aggregated and weighted similarity. This dynamic problem has been tackled in a recent paper by Singitham et al. in in VLDB 2004. Their proposed solution, which we take as baseline, is a variant of the ...

2007-01-01

6

Vibration testing of the I-40 bridge before and after the introduction of damage  

Energy Technology Data Exchange (ETDEWEB)

Because the bridges over the Rio Grande were to be razed, the investigators were able to introduce simulated cracks in four stages of increasing length into the structure. This paper summarizes the results of ambient and conventional, measured-input, modal analyses, performed on the undamaged structure. Also summarized are the results of conventional modal analyses performed after each stage of damage had been introduced. These tests were intended to quantify the amount of damage necessary to produce changes in the global dynamic properties of the bridge and to form a data base that can be used by other investigators to develop damage identification algorithms. Conventional modal analysis identified changes in the global dynamic properties of the structure only after the final stage of a damage.

1994-11-01

7

Investigation of the unsteadiness of a shock-reflection interaction with time-resolved particle image velocimetry  

British Library Electronic Table of Contents (United Kingdom)

The spatio-temporal dynamics of an impinging shock/boundary layer interaction at Mach 2 and under incipient separation conditions, has been investigated experimentally by means of high-speed particle image velocimetry (PIV). The available PIV acquisition rate of up to 20 kHz permits a time-resolved characterization of the interaction. The dynamics of different flow regions?notably the separation region and the reflected shock?were quantified by means of temporal auto-correlation fields and pseudo-spectral analysis. The PIV data further enable to investigate the relationship between spatially extended flow features, such as shock position and bubble size, as well as the influence of the upstream boundary layer. The results confirm earlier studies that there is an important upstream effect o...

2011-01-01

8

Structural integrity evaluation of FTL in-pool piping  

Energy Technology Data Exchange (ETDEWEB)

HANARO fuel test loop will be equipped in HANARO to obtain the development betterment of advanced fuel and materials through the irradiation test. The object of this study is to evaluate the structural integrity of FTL in-pool piping by investigating a dynamic analysis of the loop containing a postulated rupture section. The method to perform the dynamic analysis and structural integrity evaluation caused by the pipe whip in water environment can be a reference for a similar structural integrity evaluation. (author). 7 refs., 39 tabs., 34 figs.

1998-05-01

9

Visualization by PIV of dynamic stall on a vertical axis wind turbine  

Energy Technology Data Exchange (ETDEWEB)

The aerodynamic behavior of a vertical axis wind turbine (VAWT) is analyzed by means of 2D particle image velocimetry (PIV), focusing on the development of dynamic stall at different tip speed ratios. The VAWT has an unsteady aerodynamic behavior due to the variation with the azimuth angle {theta} of the blade's sections' angle of attack, perceived velocity and Reynolds number. The phenomenon of dynamic stall is then an inherent effect of the operation of a VAWT at low tip speed ratios, impacting both loads and power. The present work is driven by the need to understand this phenomenon, by visualizing and quantifying it, and to create a database for model validation. The experimental method uses PIV to visualize the development of the flow over the suction side of the airfoil for two different reference Reynolds numbers and three tip speed ratios in the operational regime of a small urban wind turbine. The ...

2009-01-15

10

Detecting the temporal structure of intermittent phase locking  

CERN Document Server

This study explores a method to characterize temporal structure of intermittent phase locking in oscillatory systems. When an oscillatory system is in a weakly synchronized regime away from a synchronization threshold, it spends most of the time in parts of its phase space away from synchronization state. Therefore characteristics of dynamics near this state (such as its stability properties/Lyapunov exponents or distributions of the durations of synchronized episodes) do not describe system's dynamics for most of the time. We consider an approach to characterize the system dynamics in this case, by exploring the relationship between the phases on each cycle of oscillations. If some overall level of phase locking is present, one can quantify when and for how long phase locking is lost, and how the system returns back to the phase-locked state. We consider several examples to illustrate this approach: ...

2011-01-01

11

The effect of welding parameters on hydrogen distribution in pipeline welds  

Energy Technology Data Exchange (ETDEWEB)

There is currently considerable interest in identifying and quantifying the effects of welding procedure parameters and steel composition factors on the risk of cracking in pipeline girth welds that may be experienced during winter construction. Although low ambient temperatures, that may be experienced during winter construction, are generally assumed to increase the risk of cracking there has been little work to quantify the effects and to suggest how welding procedures should be modified for winter conditions. The present work was undertaken to calculate the effects of changes in welding parameters on the thermal cycle and the diffusion of hydrogen for a typical pipeline girth weld. A simple analytical method and the finite element method (FEM) were used. Both methods gave similar results but the simple method was very sensitive to the value of heat transfer coefficient. The results showed that the relation between the ...

1990-03-01

12

Lower order roots more palatable to herbivores: a case study with two temperate tree species  

British Library Electronic Table of Contents (United Kingdom)

Determining which kinds of roots are likely to be consumed by root herbivores may improve our understanding of the mechanistic control on fine root dynamics. Here, we tested the hypothesis that root herbivores prefer to consume the distal lower order roots in their branching networks. Insecticide was applied to soil to quantify effects of root herbivores on root biomass and production in the first five orders (the distal roots numbered as first-order) in Fraxinus mandshurica and Larix gmelinii plantations from May 2008 to July 2009. Root morphology, chemistry, anatomy and physiology were measured simultaneously across branching orders. Among the first five order roots, significant consumptions by herbivores were found only for the two distal lower order roots throughout growing seasons, wi...

2011-01-01

13

Interfacial characteristics of wood fiber/polystyrene composites  

Energy Technology Data Exchange (ETDEWEB)

Considerable interest has focused recently on the use of lignocellulosic fibers as a reinforcement for thermoplastic polymers. The combination of these dissimilar materials, however, is characterized by a widespread incompatibility that leads to a weak fiber/polymer interface and poor performance properties for the composite. In an effort to improve compatibility a number of fiber surface modification approaches have been investigated including plasma, ozone, and polymer grafting treatments. Evaluation of adhesion improvements has been complicated by processing variables that are difficult to control. This paper will discuss the use of the-micro-debond test in quantifying the interfacial shear strength (ISS) in wood fiber/polystyrene composites. Wood fibers were modified to different degrees with styrene-maleic anhydride copolymers that varied in their composition. The effect of fiber modification on surface energetics was determined using ...

1995-12-01

14

Forecasting the growth of China’s natural gas consumption  

British Library Electronic Table of Contents (United Kingdom)

The use of natural gas in China is still relatively immature, as gas production only supplies a low percentage of the domestic energy system. In contrast, Chinese economy mainly relies on coal with a 67% share of the total primary energy supply. The environmental impact from this high coal dependence is significant and planners have sought for cleaner energy sources. Natural gas is both cleaner and generally more efficient than coal and gas consumption is rising quickly due to these facts. The growth tendency indicates that natural gas will become an important substitution for coal in some parts of the Chinese primary energy consumption. To quantify this tendency, this paper uses a system dynamics model to create a possible outlook. The results show that the gas consumption in China will c...

2011-01-01

15

Density separation of combustion-derived soot and petrogenic graphitic black carbon: Quantification and isotopic characterization  

Energy Technology Data Exchange (ETDEWEB)

The black carbon continuum is composed of a series of carbon-rich components derived from combustion or metamorphism and characterized by contrasting environmental behavior and susceptibility to oxidation. In this work, we present a micro-scale density fractionation method that allows isolating the small quantities of soot-like and graphitic material usually found in natural samples. Organic carbon and {delta}{sup 13}C mass balance calculations were used to quantify the relative contributions of the two fractions to thermally-stable organic matter from a series of aquatic sediments. Varying proportions of soot-like and graphitic material were found in these samples, with large variations in {delta}{sup 13}C signatures suggesting important differences in their origin and/or dynamics in the environment.

2009-01-01

16

Correlation, hierarchies, and networks in financial markets  

CERN Document Server

We discuss some methods to quantitatively investigate the properties of correlation matrices. Correlation matrices play an important role in portfolio optimization and in several other quantitative descriptions of asset price dynamics in financial markets. Specifically, we discuss how to define and obtain hierarchical trees, correlation based trees and networks from a correlation matrix. The hierarchical clustering and other procedures performed on the correlation matrix to detect statistically reliable aspects of the correlation matrix are seen as filtering procedures of the correlation matrix. We also discuss a method to associate a hierarchically nested factor model to a hierarchical tree obtained from a correlation matrix. The information retained in filtering procedures and its stability with respect to statistical fluctuations is quantified by using the Kullback-Leibler distance.

2008-01-01

17

Consumer welfare effects of increased food and energy prices  

British Library Electronic Table of Contents (United Kingdom)

In this study, the authors evaluated how much price changes in food and energy - two basic living expenditures competing for consumers' budgets - would affect consumer welfare. We first estimated a US complete demand system to quantify the interdependent demand relationships among 11 categories of consumption expenditures. Among the estimates, the own price elasticities of both food and energy are relatively inelastic, a finding that explains the dynamics of the recent soaring food and energy prices. The estimated demand elasticities were then incorporated into the measurement of Hicksian compensating variation to analyse the consumer welfare effects of price changes in food and energy. The results indicated that an increase in food and energy prices would increase compensated expenditures...

2012-01-01

18

Analysis of the bullwhip effect in multi-product, multi-stage supply chain systems-a simulation approach  

British Library Electronic Table of Contents (United Kingdom)

This research aims to develop a simulation approach based on system dynamics modelling (SDM) and adaptive network based fuzzy inference system (ANFIS) for quantifying and reducing the bullwhip effect in a multi-product, multi-stage supply chain. The proposed model is comprised of three groups of variables influencing the bullwhip effect, namely the structure of a supply chain network, supply chain contributions (ordering process in regular situation or when a supplier has a promotion or shortage gaming) and supply chain performances (the number of defects and ordering lead time). As a result, a two layer simulation model is developed with three generic models. The flexibility of this proposed approach is its ability to model various types of ordering policies which are basic inventory poli...

2010-01-01

19

The Dynamic Analog Scale: A generic method for single-item measurement  

British Library Electronic Table of Contents (United Kingdom)

The Dynamic Analog Scale (DAS) is introduced as a technique for generating single-item measures of personality traits. The DAS is comprised of extensive trait definitions and an analog scale on which respondents simultaneously rate themselves and others. In two studies the Big Five personality traits were assessed with the DAS and compared to a multiple-item questionnaire that measured the same traits. Statistical analysis supported the validity of the DAS for predicting self-reported behavioral acts, drinking behaviors, affect, and religiosity in ways similar to the multiple-item questionnaire. Consistent with previous research, both studies supported the viability of measuring personality traits with single items.

2011-01-01

20

Modelling the reworking effects of bioturbation on the incorporation of radionuclides into the sediment column: implications for the fate of particle-reactive radionuclides in Irish Sea sediments  

British Library Electronic Table of Contents (United Kingdom)

A microcosm laboratory experiment was conducted to determine the impact of biological reworking by the ragworm Nereis diversicolor on the redistribution of particle-bound radionuclides deposited at the sediment-water interface. Over the course of the 40-day experiment, as much as 35% of a 137Cs-labelled particulate tracer deposited on the sediment surface was redistributed to depths of up to 11 cm by the polychaete. Three different reworking models were employed to model the profiles and quantify the biodiffusion and biotransport coefficients: a gallery-diffuser model, a continuous sub-surface egestion model and a biodiffusion model. Although the biodiffusion coefficients obtained for each model were quite similar, the continuous sub-surface egestion model provided the best fit to the data...

2010-01-01

21

Extremal behavior of a coupled continuous time random walk  

British Library Electronic Table of Contents (United Kingdom)

Coupled continuous time random walks (CTRWs) model normal and anomalous diffusion of random walkers by taking the sum of random jump lengths dependent on the random waiting times immediately preceding each jump. They are used to simulate diffusion-like processes in econophysics such as stock market fluctuations, where jumps represent financial market microstructure like log returns. In this and many other applications, the magnitude of the largest observations (e.g. a stock market crash) is of considerable importance in quantifying risk. We use a stochastic process called a coupled continuous time random maxima (CTRM) to determine the density governing the maximum jump length of a particle undergoing a CTRW. CTRM are similar to continuous time random walks but track maxima instead of sums....

2011-01-01

22

Twiss parameters and beam matrix formulation of generalized Courant-Snyder theory for coupled transverse beam dynamics  

Energy Technology Data Exchange (ETDEWEB)

Courant-Snyder (CS) theory for one degree of freedom has recently been generalized by Qin and Davidson to the case of coupled transverse dynamics with two degrees of freedom. The generalized theory has four basic components of the original CS theory, i.e., the envelope equation, phase advance, transfer matrix, and the CS invariant, all of which have their counterparts in the original CS theory with remarkably similar expressions and physical meanings. In this brief communication, we further extend this remarkable similarity between the original and generalized CS theories and construct the Twiss parameters and beam matrix in generalized forms for the case of a strong coupling system.

2010-07-01

23

Use of real-time neutron radiography at the Penn State Breazeale Nuclear Reactor for solving industrial problems  

Energy Technology Data Exchange (ETDEWEB)

The study of the dynamics of lubricants and mechanical components encased in metal enclosures is important to many industries. Of particular importance is the flow characteristics of oils or similar lubricants within the metal enclosure during operation of the device. The purpose of this summary is to report on the design and successful application of a real-time neutron radiography system to study the lubrication and design of the piston and seal of a gas spring. In addition, the application of this technique to a wider range of similar problems using the pulse capability of the TRIGA reactor is described.

1986-01-01

24

Use of real-time neutron radiography at the Penn State Breazeale Nuclear Reactor for solving industrial problems  

International Nuclear Information System (INIS)

The study of the dynamics of lubricants and mechanical components encased in metal enclosures is important to many industries. Of particular importance is the flow characteristics of oils or similar lubricants within the metal enclosure during operation of the device. The purpose of this summary is to report on the design and successful application of a real-time neutron radiography system to study the lubrication and design of the piston and seal of a gas spring. In addition, the application of this technique to a wider range of similar problems using the pulse capability of the TRIGA reactor is described.

1986-11-16

25

Transport characteristics of dehydrogenated ammonia borane and sodium borohydride spent fuels  

Energy Technology Data Exchange (ETDEWEB)

Ammonia borane (AB) and sodium borohydride (SBH) are candidate materials for on-board hydrogen storage that can be dehydrogenated upon demand. The rheological properties of the dehydrogenated by-products are important to quantify their removal and transportability from the hydrogen storage system. This paper presents visco-elastic property (elastic stiffness and viscous damping) measurements of the spent fuels obtained from AB hydrolysis, hydrothermolysis and thermolysis; and SBH hydrolysis. Smaller stiffness and larger mobility (or smaller viscous damping) indicate better transportability of the spent fuel. In addition, flow property (dynamic angle of repose and avalanching time) measurements for the hydrolysis spent fuels of AB and SBH are also presented. Comparing with the SBH hydrolysis spent fuel, the AB hydrolysis spent fuel had a lower stiffness and larger mobility, as well as lower angles of dynamic repose and ...

2010-03-15

26

A proposed methodology for computational fluid dynamics code verification, calibration, and validation  

Energy Technology Data Exchange (ETDEWEB)

Verification, calibration, and validation (VCV) of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. The exact manner in which code VCV activities are planned and conducted, however, is critically important. It is suggested that the way in which code validation, in particular, is often conducted--by comparison to published experimental data obtained for other purposes--is in general difficult and unsatisfactory, and that a different approach is required. This paper describes a proposed methodology for CFD code VCV that meets the technical requirements and is philosophically consistent with code development needs. The proposed methodology stresses teamwork and cooperation between code developers and experimentalists throughout the VCV process, and takes advantage of certain synergisms between CFD and experiment. A novel approach to uncertainty analysis is described which can both distinguish between and ...

1995-07-01

28

Socioeconophysics: Opinion Dynamics for number of transactions and price, a trader based model  

CERN Document Server

Involving effects of media, opinion leader and other agents on the opinion of individuals of market society, a trader based model is developed and utilized to simulate price via supply and demand. Pronounced effects are considered with several weights and some personal differences between traders are taken into account. Resulting time series and probabilty distribution function involving a power law for price come out similar to the real ones.

2006-01-01

29

The effect of aqueous composition on diffusion coefficient in bentonite  

International Nuclear Information System (INIS)

The diffusion coefficients (De) in bentonite were measured to understand and quantify the influence of groundwater chemistry such as ionic strength and to quantify the alteration of smectite mineralogical transformations. (author)

2009-12-01

30

Quantifying the Reactive Uptake of OH by Organic Aerosols in aContinuous Flow Stirred Tank Reactor  

Energy Technology Data Exchange (ETDEWEB)

Here we report a new method for measuring the heterogeneous chemistry of submicron organic aerosol particles using a continuous flow stirred tank reactor. This approach is designed to quantify the real time heterogeneous kinetics, using a relative rate method, under conditions of low oxidant concentration and long reaction times that more closely mimic the real atmosphere. A general analytical expression, which couples the aerosol chemistry with the flow dynamics in the chamber is developed and applied to the heterogeneous oxidation of squalane particles by hydroxyl radicals (OH) in the presence of O2. The particle phase reaction is monitored via photoionization aerosol mass spectrometry and yields a reactive uptake coefficient of 0.51+-0.10, using OH concentrations of 1-7x108 molec cdot cm-3 and reaction times of 1.5+-3 hours. This uptake coefficient is larger than that found for the reaction carried out under high OH concentrations (~;;1x1010 ...

2009-03-01

31

The high-density regime of kinetic-dominated loop quantum cosmology  

CERN Document Server

We study the dynamics of states perturbatively expanded about a harmonic system of loop quantum cosmology, exhibiting a bounce. In particular, the evolution equations for the first and second order moments of the system are analyzed. These moments back-react on the trajectories of the expectation values of the state and hence alter the energy density at the bounce. This analysis is performed for isotropic loop quantum cosmology coupled to a scalar field with a small but non-zero constant potential, hence in a regime in which the kinetic energy of matter dominates. Analytic restrictions on the existence of dynamical coherent states and the meaning of semi-classicality within these systems are discussed. A numerical investigation of the trajectories of states that remain semi-classical across the bounce demonstrates that, at least for such states, the bounce persists and that its properties are similar to the standard case, ...

2010-01-01

32

Dense and diffuse gas in dynamically active clouds  

CERN Document Server

We investigate the chemical and observational implications of repetitive transient dense core formation in molecular clouds. We allow a transient density fluctuation to form and disperse over a period of 1 Myr, tracing its chemical evolution. We then allow the same gas immediately to undergo further such formation and dispersion cycles. The chemistry of the dense gas in subsequent cycles is similar to that of the first, and a limit cycle is reached quickly (2 - 3 cycles). Enhancement of hydrocarbon abundances during a specific period of evolution is the strongest indicator of previous dynamical history. The molecular content of the diffuse background gas in the molecular cloud is expected to be strongly enhanced by the core formation and dispersion process. Such enhancement may remain for as long as 0.5 Myr. The frequency of repetitive core formation should strongly determine the level of background molecular enhancement. We also convolve the ...

2006-01-01

35

Turbulent mixing in the foot piece of a HPLWR fuel assembly  

International Nuclear Information System (INIS)

A homogeneous turbulent mixing of coolant flows with different temperatures at the fuel assembly inlets is an important requirement to minimize hot spots in a fuel assembly of a High Performance Light Water Reactor (HPLWR). Therefore, the mixing chamber between lower core plate, flow adjuster and the mixing chamber within the cluster foot piece diffuser have been investigated using the Computational Fluid Dynamics (CFD)-code Fluent 6.1 and its implemented k-#epsilon# model. The previously presented 3D-CAD-geometry has been simplified using Gambit 2.1.2 and consists of various inlet and outlet tubes or channels in the foot piece bottom plate, the lower core plate and the flow adjuster establishing the boundaries of two consecutive mixing chambers. The temperature distribution at the inlet of the sub-channels of the cluster fuel assemblies is presented. It reveals temperature variations at the coolant inlet of the nine fuel assemblies which are not acceptable. ...

2005-10-09

36

The edge of neutral evolution in social dilemmas  

Energy Technology Data Exchange (ETDEWEB)

The functioning of animal as well as human societies fundamentally relies on cooperation. Yet, defection is often favorable for the selfish individual, and social dilemmas arise. Selection by individuals' fitness, usually the basic driving force of evolution, quickly eliminates cooperators. However, evolution is also governed by fluctuations that can be of greater importance than fitness differences, and can render evolution effectively neutral. Here, we investigate the effects of selection versus fluctuations in social dilemmas. By studying the mean extinction times of cooperators and defectors, a variable sensitive to fluctuations, we are able to identify and quantify an emerging 'edge of neutral evolution' that delineates regimes of neutral and Darwinian evolution. Our results reveal that cooperation is significantly maintained in the neutral regimes. In contrast, the classical predictions of evolutionary game theory, where defectors ...

2009-09-15

37

Applications of Magnetic PsiDO Techniques to Space-adiabatic Perturbation Theory  

CERN Document Server

In this review, we show how advances in the theory of magnetic pseudodifferential operators (magnetic $\\Psi$DO) can be put to good use in space-adiabatic perturbation theory (SAPT). As a particular example, we extend results of [PST03] to a more general class of magnetic fields: we consider a single particle moving in a periodic potential which is subjectd to a weak and slowly-varying electromagnetic field. In addition to the semiclassical parameter $\\eps \\ll 1$ which quantifies the separation of spatial scales, we explore the influence of additional parameters that allow us to selectively switch off the magnetic field. We find that even in the case of magnetic fields with components in $C_b^{\\infty}(\\R^d)$, e. g. for constant magnetic fields, the results of Panati, Spohn and Teufel hold, i.e. to each isolated family of Bloch bands, there exists an associated almost invariant subspace of $L^2(\\R^d)$ and an effective hamiltonian which generates the ...

2010-01-01

38

A Risk-Based Sensor Placement Methodology  

Energy Technology Data Exchange (ETDEWEB)

A risk-based sensor placement methodology is proposed to solve the problem of optimal location of sensors or detectors to protect population against the exposure to and effects of known and/or postulated chemical, biological, and/or radiological threats. Risk is calculated as a quantitative value representing population at risk from exposure against standard exposure levels. Historical meteorological data are used to characterize weather conditions as the frequency of wind speed and direction pairs. The meteorological data drive atmospheric transport and dispersion modeling of the threats, the results of which are used to calculate risk values. Sensor locations are determined via an iterative dynamic programming algorithm whereby threats captured or detected by sensors placed in prior stages are removed from consideration in subsequent stages. In addition to the risk-based placement algorithm, the proposed methodology provides a quantification of the marginal ...

2008-10-01

39

Structures in the Universe and Origin of Galaxies  

CERN Document Server

The analysis of images (of obtained in various ranges of the lengths of waves) of luminous objects in the Universe by means of a method of multilevel dynamic contrasting led author to the conclusions: a) the structures of all observable galaxies represents a complicated constructions which have the tendency to self-similarity and made of separate (basic) blocks, which are a coaxially tubular structures and a cartwheel-like structures; b) the majority of observable objects in the Universe are luminous butt-ends of almost invisible (of almost completely transparent) of filamentary formations which structures are seen only near to their luminous butt-ends; c) the result of analysis of images of cosmic objects show the structure of many pairs of cooperating galaxies point to opportunity of their formation at butt-ends generated in a place of break of the similar filament; d) the interacting galaxies (M 81 and M 82) show they ...

2005-01-01

40

Nonlinear response and stability of a spindle system supported by Ball bearings  

Energy Technology Data Exchange (ETDEWEB)

In this effort, the nonlinear responses and stability of a spindle system supported by ball bearings are presented. The dynamics of this system is described by a set of second order differential equations with a nonlinear piecewise smooth force. The Floquet theory is applied to investigate the stability of the periodic solution. Due to the loss of contact between the raceways and balls in the ball bearing, the bending of the frequency response curves switch to the left at the weak resonance region, which is similar to the frequency response curves of a system with a soft spring. With the decrease of the bearing clearance, the bending of the frequency response curves switch to the right, which is similar to the frequency response curves of a system with a hard spring. Increase of the frequency ratio, the bending of frequency response curves transforms from left to right. The route to chaos through a period doubling process ...

2010-09-15

41

Station set residual : event classification using historical distribution of observing stations.  

Science.gov (United States)

Analysts working at the International Data Centre in support of treaty monitoring through the Comprehensive Nuclear-Test-Ban Treaty Organization spend a significant amount of time reviewing hypothesized seismic events produced by an automatic processing system. When reviewing these events to determine their legitimacy, analysts take a variety of approaches that rely heavily on training and past experience. One method used by analysts to gauge the validity of an event involves examining the set of stations involved in the detection of an event. In particular, leveraging past experience, an analyst can say that an event located in a certain part of the world is expected to be detected by Stations A, B, and C. Implicit in this statement is that such an event would usually not be detected by Stations X, Y, or Z. For some well understood parts of the world, the absence of one or more 'expected' stations - or the presence of one or more 'unexpected' ...

2010-04-01

42

Greenhouse gas emissions from the international maritime transport of New Zealand's imports and exports  

International Nuclear Information System (INIS)

Greenhouse gas emissions from international maritime transport are exempt from liabilities under the Kyoto Protocol. Research into quantifying these emissions is ongoing, and influences policy proposals to reduce emissions. This paper presents a cargo-based analysis of fuel consumption and greenhouse gas emissions from New Zealand's international maritime transport of goods. Maritime transport moves 99.5% (by mass) of New Zealand's internationally traded products. It is estimated that 73% of visiting vessels' activity can be directly attributed to the movement of goods in and out of New Zealand. A cargo-based methodology was used to estimate that the international maritime transport of New Zealand's imports and exports consumed 2.5 million tonnes (Mt; 2.6 billion litres) of fuel during the year 2007, which generated 7.7 Mt of carbon dioxide (CO_2) emissions. Double-counting of emissions would occur if a similar method was applied to all New ...

2011-03-01

43

Quantifying bid-ask spreads in the Chinese stock market using limit-order book data: Intraday pattern, probability distribution, long memory, and multifractal nature  

CERN Document Server

The statistical properties of the bid-ask spread of a frequently traded Chinese stock listed on the Shenzhen Stock Exchange are investigated using the limit-order book data. Three different definitions of spread are considered based on the time right before transactions, the time whenever the highest buying price or the lowest selling price changes, and a fixed time interval. The results are qualitatively similar no matter linear prices or logarithmic prices are used. The average spread exhibits evident intraday patterns consisting of a big L-shape in the morning and a small L-shape in the afternoon. The distributions of the spread with different definitions decay as power laws. The tail exponents of spreads at transaction level are well within the interval $(2,3)$ and that of average spreads are well in line with the inverse cubic law for different time intervals. Based on the detrended fluctuation analysis, we find evidence of long memory in the bid-ask spread ...

2006-01-01

44

Quantification of antibiotic drug potency by a two-compartment radioassay of bacterial growth  

Energy Technology Data Exchange (ETDEWEB)

The two-compartment radioassay for microbial kinetics based on continuous measurement of the {sup 14}CO{sub 2} released by bacterial metabolism of 14C-labeled substrate offers a valuable approach to testing the potency of antimicrobial drugs. By using a previously validated radioassay with gram-positive and gram-negative bacteria, a group of protein synthesis inhibitors was evaluated for their effect on microbial growth kinetics. All tested drugs induced changes in both the slopes and intercepts of the growth curves. An exponential growth model was applied to quantify the drug effect on the processes of bacterial {sup 14}CO{sub 2} liberation and cell generation. The response was measured in terms of a generation rate constant. A linear dependence of the generation rate constant on the dose of spectinomycin was observed with Escherichia coli. Sigmoidal-shaped curves were found in the assays of chloramphenicol and tetracycline. The implications of dose-response ...

1990-06-01

45

Platelet thrombosis in cardiac-valve prostheses  

International Nuclear Information System (INIS)

The contribution of platelets and clotting factors in thrombosis on cardiovascular prostheses had been quantified with several tracers. Thrombus formation in vivo could be measured semiquantitatively in animal models and patients with indium-111, Technetium-99m labeled platelets, iodine-123, iodine-131 labeled fibrinogen, and In-111 and Tc-99m labeled antibody to the fibrinogen-receptor on the platelet- membrane, or fibrin. The early studies demonstrated that certain platelet-inhibitors, e.g. sulfinpyrazone, aspirin or aspirin- persantine increased platelet survival time with mechanical valves implanted in the baboon model and patients. Thrombus localization by imaging is possible for large thrombus on thrombogenic surface of prosthesis in the acute phase. The majority of thrombus was found in the sewing ring (Dacron) in the acute phase in both the mechanical and tissue valves. The amount of retained thrombus in both mechanical and tissue valves in our one-day ...

1989-06-08

46

Initiation of depleted uranium oxide and spent fuel testing for the spent fuel sabotage aerosol ratio programme  

Energy Technology Data Exchange (ETDEWEB)

We provide a detailed overview of an on-going, multinational test programme that is developing aerosol data for some spent fuel sabotage scenarios on spent fuel transport and storage casks. Experiments are being performed to quantify the aerosolised materials plus volatilised fission products generated from actual spent fuel and surrogate material test rods, due to impact by a high-energy/density device. The programme participants in the United States plus Germany, France and the United Kingdom, part of the international Working Group for Sabotage Concerns of Transport and Storage Casks (WGSTSC) have strongly supported and coordinated this research programme. Sandia National Laboratories has the lead role for conducting this research programme; test programme support is provided by both the US Department of Energy and the US Nuclear Regulatory Commission. We provide a summary of the overall, multiphase test design and a description of all explosive containment and ...

2004-07-01

47

Initiation of depleted uranium oxide and spent fuel testing for the spent fuel sabotage aerosol ratio programme  

International Nuclear Information System (INIS)

We provide a detailed overview of an on-going, multinational test programme that is developing aerosol data for some spent fuel sabotage scenarios on spent fuel transport and storage casks. Experiments are being performed to quantify the aerosolised materials plus volatilised fission products generated from actual spent fuel and surrogate material test rods, due to impact by a high-energy/density device. The programme participants in the United States plus Germany, France and the United Kingdom, part of the international Working Group for Sabotage Concerns of Transport and Storage Casks (WGSTSC) have strongly supported and coordinated this research programme. Sandia National Laboratories has the lead role for conducting this research programme; test programme support is provided by both the US Department of Energy and the US Nuclear Regulatory Commission. We provide a summary of the overall, multiphase test design and a description of all explosive containment and ...

48

Initiation of depleted uranium oxide and spent fuel testing for the spent fuel sabotage aerosol ratio program.  

Energy Technology Data Exchange (ETDEWEB)

The authors provide a detailed overview of an on-going, multinational test program that is developing aerosol data for some spent fuel sabotage scenarios on spent fuel transport and storage casks. Experiments are being performed to quantify the aerosolized materials plus volatilized fission products generated from actual spent fuel and surrogate material test rods, due to impact by a high-energy-density device. The program participants in the United States plus Germany, France and the United Kingdom, part of the international Working Group for Sabotage Concerns of Transport and Storage Casks (WGSTSC) have strongly supported and coordinated this research program. Sandia National Laboratories has the lead role for conducting this research program; test program support is provided by both the US Department of Energy and the US Nuclear Regulatory Commission. The authors provide a summary of the overall, multiphase test design and a description of all explosive ...

2004-08-01

49

Initiation of depleted uranium oxide and spent fuel testing for the spent fuel sabotage aerosol ratio program  

International Nuclear Information System (INIS)

The authors provide a detailed overview of an on-going, multinational test program that is developing aerosol data for some spent fuel sabotage scenarios on spent fuel transport and storage casks. Experiments are being performed to quantify the aerosolized materials plus volatilized fission products generated from actual spent fuel and surrogate material test rods, due to impact by a high-energy-density device. The program participants in the United States plus Germany, France and the United Kingdom, part of the international Working Group for Sabotage Concerns of Transport and Storage Casks (WGSTSC) have strongly supported and coordinated this research program. Sandia National Laboratories has the lead role for conducting this research program; test program support is provided by both the US Department of Energy and the US Nuclear Regulatory Commission. The authors provide a summary of the overall, multiphase test design and a description of all explosive ...

50

Improved adhesion for thermoplastic polymers using oxyfluorination  

Energy Technology Data Exchange (ETDEWEB)

Industrial applications of thermoplastic polymers are often limited by their poor adhesion properties. In this work the effect of surface oxyfluorination on the adhesion properties was investigated for polyethylene (PE), polyoxymethylene (POM), polybutylene terephthalate (PBT) and polyamide 6 (PA6). The adhesive joint strength was quantified using lap-shear tests. These results were correlated with the changes in the chemical composition of the surface, determined by X-ray photoelectron spectroscopy (XPS), in the surface free energy, measured by the contact angle method, and in the topography, using white-light confocal microscopy. The adhesive strength is strongly improved for all four polymers, but the degree of this increase depends on the polymer type. The surface free energy shows a similar trend for all four polymers. A high surface free energy exceeding 50 mN/m was observed after oxy-fluorination, whereby the polar component was strongly ...

2008-03-15

51

Acanthamoeba Keratitis at the King Khaled Eye Specialist Hospital  

International Nuclear Information System (INIS)

To quantify the number of cases and clinical courses of Acanthamoeba keratitis treated at the King Khaled Eye Specialist Hospital (KKESH) between December 1982 and May 2005, and to review their clinical course and response to medical and surgical therapy. Retrospective review of medical records of all patients with Acanthamoeba keratitis diagnosed by the KKESH Microbiology or Pathology or Pathology Laboratory since the opening of the hospital. During a period of over 22 years, only six cases of confirmed. Acanthamoeba keratitis were diagnosedand treated at KKESH. In two cases the diagnosis was made by corneal biopsy, while four cases required examination of a histopathology specimen obtained at the time of therapeutic keratoplasty to establish the diagnosis. One eye was cured by medical therapy, while five eyes required one (4eyes) or two (1 eye) therapeutic penetrating keratoplasty (PKP) to achieve a clinical cure. Three eyes achieved good visual acuity (20/40, ...

52

Unified description of bradyons and tachyons based on the dynamical SO(4,2) symmetry  

International Nuclear Information System (INIS)

Firstly the so called 'conformal relativity' in the 6-dimensional conformal space is formulated. In particular the concept of dilatational degree of freedom - scale - is introduced. The special conformal transformations are interpreted as the transformations connecting dilatationally moving frames (and objects). The ideas, similar to those by Kaluza and Klein, can be applied to the conformal space to obtain a unification of gravitation and electromagnetism. Lastly the conformal symmetry is extended to imaginary scales and to negative scales. Particles having imaginary scales are shown to be tachyons, whilst particles with negative scales correspond to antiparticles. (Auth.).

53

Compressive and Torsional Buckling Behavior of Carbon Nanotube Bundles  

International Nuclear Information System (INIS)

The compressive and torsional buckling behavior of carbon nanotube bundles at room temperature is examined with classical molecular dynamics simulation. The critical compressive load and stiffness of a single carbon nanotube in the bundle are found to be similar to those of individual carbon nanotubes. However, the critical torsional moment and stiffness of a single carbon nanotube in the bundle are found to be higher than those of individual carbon nanotubes. In addition, this study demonstrates that van der Waals interactions between the nanotubes in the bundle significantly affect the critical compressive load of the nanotube bundle.

2007-08-01

54

A note on the pressure field within an outward moving free annulus  

Energy Technology Data Exchange (ETDEWEB)

The outward radial expansion of a free liquid annulus is a common problem of both earlier and current ICF blanket design. Whether the annulus fractures or not depends on the internal pressure and surface stability. In this paper a model based on incompressible cylindrically symmetric flow is used to get a theoretical solution similar to that of the Rayleigh's solution for bubble dynamics. The pressure inside the annulus is found positive all time but the peak is lowering during the expansion. Besides, both surfaces are Taylor stable during such motion. Thus, it is concluded that an annulus in outward radial motion will not cavitate or breakup.

1990-01-01

56

Effects of timber extraction on herb diversity in the Little Tennessee watershed.  

Science.gov (United States)

... study is to collect data in previously harvested timber stands to quantify the differences in herbaceous diversity ... ...

57

NEX - Analysis of ENSO Dynamics and ThermoDynamics in the ... - NASA  

Science.gov (United States)

Analysis of ENSO Dynamics and ThermoDynamics in the Western Pacific Warm Pool - An Application of Multi-Sensor Satellite Observations. ...

58

The projector augmented wave method: A fast all-electron procedure for the ab-initio molecular dynamics  

International Nuclear Information System (INIS)

In this thesis, a new ab-initio method for molecular dynamics within the framework of density functional theory was developed and implemented. It is strongly related to the projector-augmented-wave method (PAW) by P. Bloechl, but also includes elements of a pseudocharge method proposed by M. Weinert for the full-potential linearized augmented plane wave method (FLAPW). Like the FLAPW-method, the PAW-method is an all-electron method. In the later case, the hamiltonian takes quite a simple form similar to the one obtained when using normconserving Kleinman-Bylander-type pseudopotentials or ultrasoft Vanderbilt pseudopotentials. The PAW-method allows for an efficient calculation of systems containing virtually any element of the periodic table, including those which require high numerical effort when treated using normconserving pseudopotentials (e.g. 2p-elements like oxygen or 3d-transitional metals like copper). In addition, a higher accuracy ...

59

Investigation and improvement of ejector refrigeration system using computational fluid dynamics technique  

Energy Technology Data Exchange (ETDEWEB)

Ejector refrigeration systems are usually designed to utilize low grade energy for driving the cycle. They also have low maintenance cost because they operate without a compressor. Mainly, the ejector performance directly affects the refrigerating performance. Therefore, an investigation on the characteristics and an efficient design of the ejector are important to improve ejector refrigeration systems. In this study, the computational fluid dynamics (CFD) code, FLUENT, is employed to predict the flow phenomena and performance of CPM and CMA steam ejectors. The ejector refrigeration system, using water as the working fluid, is operated at 120-140 C boiler temperature and 5-15 C evaporator temperature. CFD can predict ejector performance very well and reveal the effect of operating conditions on an effective area that is directly related to its performance. Besides, it is found that the flow pattern does not depend much on the suction zone because the results of ...

2007-09-15

60

Analytic properties of nonrelativistic two-body off-shell amplitudes II. Off-shell generalizations of the Jost formalism  

International Nuclear Information System (INIS)

The connections between several studies of the off-shell amplitude, based on apparently different criteria, are first clarified and expressed through more coincise operator notion. In all cases the resolution of the underlying dynamical relations is reduced to a two-step procedure. Underconditions which are discussed, the latter implies only Volterra-like integral equations followed by simple quadratures and algebraic operations. Then it is shown that the off-shell generalizations of the Jost formalism which are defined by such approaches can as well be introduced without reference to any explicit dynamical framework. Examples are given specifying in such model independent ways the main properties of the associated Jost-type functions. The relative interest of different representations built with these functions is also examined, and on this occasion new three-separable-term approximations are a useful guideline for introducing ...

61

A computational fluid dynamics investigation of fluid flow in a dense medium plasma reactor  

International Nuclear Information System (INIS)

Computational fluid dynamics are applied to the study of three-dimensional fluid flow in a dense medium plasma reactor (DMPR) under different operating conditions. Reaction mechanisms and rates for the removal of methyl t-butyl ether (MTBE) in a DMPR are developed from experimental data to determine the plasma volume, the rate of interphase mass transfer and the photolysis rate of MTBE via UV emission from the plasma. The simulations utilize the plasma volume determined from the kinetic data to show that the volume of fluid in contact with the plasma in the DMPR only constitutes a maximum of approximately 10% of the fluid intended to be cycled through the plasma tubules. The simulations also predict appreciable pressure gradients on the surface of the pin electrodes, resulting in a small discharge area located away from the region in which the electric field strength is a maximum. This result has been confirmed indirectly through observation in that the pin ...

2007-01-21

62

Divergent views on a possible nuclear waste repository in the community: Social aspects of decision making  

Energy Technology Data Exchange (ETDEWEB)

The paper summarizes the results obtained in two interview studies conducted in the communities of Storuman and Malaa in northern Sweden, 1995 and 1997. It highlights the similarities and differences with respect to the public participation and decision processes which preceded the respective referenda in the two communities. The presentation includes the arguments used by proponents and opponents, the changes over time, as well as the time frame and the information involved in the processes. It is concluded e.g. that local cultures, life-styles, knowledge of similar events, and the time for and management of the participation process are important and salient factors in the resulting social dynamics. Factors of possibly more fundamental importance were also discerned, however, including overall attitude to and valuation of nuclear power, perceptions of development, solidarity, power and power distribution in relation to ...

1999-12-01

63

Surge pressure behavior in reduced diameter segments of shipping terminals; Comportamento de pulsos de pressao em trechos de diametro reduzido de dutos de terminais maritimos  

Energy Technology Data Exchange (ETDEWEB)

In a shipping terminal, the pipeline in the pier usually has a diameter smaller than the main pipeline diameter. This diameter reduction amplifies the effects caused by hydraulic transients. It was noticed during simulations that check valves placed in the pier may introduce some error in the maximum pressure when it was modeled in a conventional fashion. The dynamic check valve model had been added to a commercial pipeline simulation software and the results was compared with a similar model using the method of characteristics. Considering a real state shipping terminal case, it was proved even a pipeline that works with low pressure and smooth elevation profile needs a detailed valve modeling to prevent the calculation of unreal pressure values in the region with diameter reduction. (author)

2004-07-01

64

Spin dynamics in Ho{sub 2}Ru{sub 2}O{sub 7}  

Energy Technology Data Exchange (ETDEWEB)

The spin relaxation processes within the pyrochlore Ho{sub 2}Ru{sub 2}O{sub 7} have been investigated by neutron scattering and bulk property techniques. A single-ion process, that is thermally activated, dominates the spin-spin relaxation spectrum above 2 K. Assuming Arrhenius behaviour, we found an activation energy {delta} = (329 {+-} 6) K and characteristic relaxation time {tau}{sub 0} (5.2 {+-} 0.3) x 10{sup -12} s in the paramagnetic state, akin to those found in the spin ice, Ho{sub 2}Ti{sub 2}O{sub 7}. Atlow temperature (T<95 K) the activation energy lowers and below 20 K the entropy and ac susceptibility are similar to that observed in other spin ice compounds within a 10 kOe field.

2005-11-09

65

Spin dynamics in Ho_2Ru_2O_7  

International Nuclear Information System (INIS)

The spin relaxation processes within the pyrochlore Ho_2Ru_2O_7 have been investigated by neutron scattering and bulk property techniques. A single-ion process, that is thermally activated, dominates the spin-spin relaxation spectrum above 2 K. Assuming Arrhenius behaviour, we found an activation energy #DELTA# = (329 #+-# 6) K and characteristic relaxation time #tau#_0 (5.2 #+-# 0.3) x 10"-"1"2 s in the paramagnetic state, akin to those found in the spin ice, Ho_2Ti_2O_7. Atlow temperature (T<95 K) the activation energy lowers and below 20 K the entropy and ac susceptibility are similar to that observed in other spin ice compounds within a 10 kOe field.

2005-11-09

66

Response variability in balanced cortical networks  

DEFF Research Database (Denmark)

We study the spike statistics of neurons in a network with dynamically balanced excitation and inhibition. Our model, intended to represent a generic cortical column, comprises randomly connected excitatory and inhibitory leaky integrate-and-fire neurons, driven by excitatory input from an external population. The high connectivity permits a mean field description in which synaptic currents can be treated as gaussian noise, the mean and autocorrelation function of which are calculated self-consistently from the firing statistics of single model neurons. Within this description, a wide range of Fano factors is possible. We find that the irregularity of spike trains is controlled mainly by the strength of the synapses relative to the difference between the firing threshold and the postfiring reset level of the membrane potential. For moderately strong synapses, we find spike statistics very similar to those observed in primary visual cortex.

2006-01-01

67

Luminescence spectroscopy of Er3+-doped and Er3+, Yb3+-codoped LaPO4 single crystals  

International Nuclear Information System (INIS)

LaPO4 single crystals lightly doped with Er3+, and codoped with Er3+ and Yb3+ have been grown by spontaneous nucleation in a lead phosphate flux. Absorption and luminescence spectra have been measured in the visible and near-IR regions and the excited state dynamics has been studied upon pulsed laser excitation. The obtained results have allowed the evaluation of the effective emission cross-sections around 1.5 ?m, that have been found to be similar to important oxide laser crystals doped with Er3+. Efficient visible upconversion has been observed upon excitation at 980 nm in the codoped crystals. This behaviour is attributed to Yb3+-Er3+ energy transfer processes.

2009-05-01

68

Horticultural and Gathering Practices Complement Each Other: A Case Study in a Rural Population of Northwestern Patagonia  

British Library Electronic Table of Contents (United Kingdom)

We investigated gathering and cultivating practices and how they complement each other in a rural population of Northwestern Patagonia. We analyzed plant diversity, species similarity, biogeographic origin, and plant use by means of semi-structured interviews and field visits. Pichi Leufu inhabitants used 173 species: 138 cultivated plants, mainly for edible purposes, and 45 wild species principally for medicinal use. Most cultivated species were exotic (91.3%), whereas gathered plants were both native and exotic. While locals maintained vegetable gardens, the adoption of greenhouses improved conditions for certain crops. The integration of novel practices with ancestral knowledge suggests resilient processes in this community, probably reflected in the dynamics of current horticultural an...

2011-01-01

69

Dynamics of the globular cluster M2 (NGC 7089)  

International Nuclear Information System (INIS)

We have obtained radial velocities for 69 stars in the globular cluster M2 (NGC 7089). M2's rotation axis is, within sizeable uncertainties, perpendicular to the major axis determined by the flattening. The ratio of rotational to random kinetic energy agrees with that predicted from the ellipticity assuming an oblate figure and an isotropic velocity-dispersion tensor. We have fitted King-Michie models to determine M2's mass, the exponent of an assumed power-law mass function, and the anisotropy radius. The most significant sources of uncertainty in the modeling are the velocity dispersion, the distance, and the mass-luminosity relation for the cluster stars. The models favor mass functions similar to or shallower than the Salpeter initial-mass function and a moderate amount of velocity anisotropy.

70

Distribution of Fuel-Grade Ethanol near a Dynamic Water Table  

British Library Electronic Table of Contents (United Kingdom)

Injections of fuel-grade ethanol (95% v/v ethanol, 5% v/v hydrocarbon mixture as a denaturant) near the water table were conducted in two-dimensional physical models tightly packed with fine sands under varying water-table conditions. As the fuel migrated in the porous media following injection, the denaturant phase separated leaving a residual Light Non-Aqueous Phase Liquid (LNAPL) phase that occupied a region with a volume similar to that of an equal-sized spill of 100% LNAPL without ethanol. When the water table was raised, as may be expected following a catastrophic release that reaches groundwater, most of the ethanol-fuel mixture was mobilized and the vertical distribution of the generated LNAPL was increased. The lower boundary of the residual LNAPL was established during the initia...

2011-01-01

71

Bimodal colloidal mixtures: From fast to slow aggregation regions  

British Library Electronic Table of Contents (United Kingdom)

A Brownian dynamics simulation has been used to investigate the aggregation kinetics of bimodal colloidal mixtures with similar surface chemistries but different sizes, driven by the DLVO interaction potential. The time evolution of structural formation is examined by the mean number of neighbors under fast and slow aggregation regions. It was found that the electrolyte ionic strength affects the kinetic pattern of colloidal aggregation. Under the high electrolyte ionic strength conditions (fast aggregation), the selective aggregation of the least stable single component can take place in the early stage, while the other component is enriched in this least stable component in the later stage. With the ionic strength decreasing (towards the slow aggregation), the hybrid aggregation (selecti...

2011-01-01

72

Bianchi type-IX electromagnetic universes  

Energy Technology Data Exchange (ETDEWEB)

The dynamical effects of spatially homogeneous electromagnetic fields on anisotropic Bianchi type-IX models are studied. The Lagrangians and Hamiltonians affecting the evolution of anisotropy (including the gravitational and electromagnetic potentials) are obtained for very general spatially homogeneous metrics by means of the Arnowitt-Deser-Misner Hamiltonian formalism. For models having diagonal metrics an exact solution for the electromagnetic fields is obtained. This solution allows a qualitative solution for the gravitational variables. The total solution is similar to that of Brill. For Bianchi type-IX models having symmetric and general metrics, a discussion of the qualitative behavior of the universe point under the influence of the above potentials is given. In particular, it is shown that in some cases the presence of the electromagnetic potential inhibits some types of singularities.

1984-01-15

73

Bianchi type-IX electromagnetic universes  

International Nuclear Information System (INIS)

The dynamical effects of spatially homogeneous electromagnetic fields on anisotropic Bianchi type-IX models are studied. The Lagrangians and Hamiltonians affecting the evolution of anisotropy (including the gravitational and electromagnetic potentials) are obtained for very general spatially homogeneous metrics by means of the Arnowitt-Deser-Misner Hamiltonian formalism. For models having diagonal metrics an exact solution for the electromagnetic fields is obtained. This solution allows a qualitative solution for the gravitational variables. The total solution is similar to that of Brill. For Bianchi type-IX models having symmetric and general metrics, a discussion of the qualitative behavior of the universe point under the influence of the above potentials is given. In particular, it is shown that in some cases the presence of the electromagnetic potential inhibits some types of singularities.

74

Atmospheric Gravity Perturbations Measured by Ground-Based Interferometer with Suspended Mirrors  

CERN Document Server

A possibility of geophysical measurements using the large scale laser interferometrical gravitational wave antenna is discussed. An interferometer with suspended mirrors can be used as a gradiometer measuring variations of an angle between gravity force vectors acting on the spatially separated suspensions. We analyze restrictions imposed by the atmospheric noises on feasibility of such measurements. Two models of the atmosphere are invoked: a quiet atmosphere with a hydrostatic coupling of pressure and density and a dynamic model of moving region of the density anomaly (cyclone). Both models lead to similar conclusions up to numerical factors. Besides the hydrostatic approximation, we use a model of turbulent atmosphere with the pressure fluctuation spectrum f^{-7/3} to explore the Newtonian noise in a higher frequency domain (up to 10 Hz) predicting the gravitational noise background for modern gravitational wave detectors. Our estimates show ...

2003-01-01

75

Amphiphysin (Amph) maps to the proximal region of mouse chromosome 13  

Energy Technology Data Exchange (ETDEWEB)

Amphiphysin is a protein concentrated in neuronal synapses and peripherally associated with neurotransmitter vesicles. It is expressed in many neurons of the central and peripheral nervous systems, in the adrenal medulla, in the anterior and posterior pituitary, in cell lines of the endocrine pancreas, and in spermatocytes. Its subcellular localization and tissue distribution indicate a potential involvement in mechanisms of regulated exocytosis. A role in the dynamic organization of the membrane-associated cytoskeleton is suggested by structural homology to the products of two yeast genes, RVS161 and RVS167, whose mutation results in an abnormal actin distribution, disturbs budding morphology, and impairs cell entry into stationary phase. Limited stretches of sequence similarity, including an SH3 domain, are also shared with other actin-binding proteins. Amphiphysin is the dominant autoantigen in paraneoplastic Stiff-Man syndrome, a ...

1995-07-20

76

Adsorption Kinetics of Surfactants at Fluid-Fluid Interfaces  

CERN Document Server

We review a new theoretical approach to the kinetics of surfactant adsorption at fluid-fluid interfaces. It yields a more complete description of the kinetics both in the aqueous solution and at the interface, deriving all equations from a free-energy functional. It also provides a general method to calculate dynamic surface tensions. For non-ionic surfactants the results coincide with previous models. Common non-ionic surfactants are shown to undergo diffusion-limited adsorption, in agreement with experiments. Strong electrostatic interactions in salt-free ionic surfactant solutions are found to lead to kinetically limited adsorption. In this case the theory accounts for unusual experimental results which could not be understood using previous approaches. Added salt screens the electrostatic interactions and makes the ionic surfactant adsorption similar to the non-ionic case. The departure from the non-ionic behavior as the salt concentration ...

1997-01-01

78

Potential future changes in water limitations of the terrestrial biosphere  

Energy Technology Data Exchange (ETDEWEB)

This study explores the effects of atmospheric CO2 enrichment and climate change on soil moisture (W{sub r} ) and biome-level water limitation (L{sub TA}), using a dynamic global vegetation and water balance model forced by five different scenarios of change in temperature, precipitation, radiation, and atmospheric CO2 concentration, all based on the same IS92a emission scenario. L{sub TA} is defined as an index that quantifies the degree to which transpiration and photosynthesis are co-limited by soil water shortage (high values indicate low water limitation). Soil moisture decreases in many regions by 2071-2100 compared to 1961-1990, though the regional pattern of change differs substantially among the scenarios due primarily to differences in GCM-specific precipitation changes. In terms of L{sub TA}, ecosystems in northern temperate latitudes are at greatest risk of increasing water limitation, while in most other latitudes L{sub TA} tends ...

2007-02-15

79

Development of experimental verification techniques for non-linear deformation and fracture on the nanometer scale.  

Energy Technology Data Exchange (ETDEWEB)

This work covers three distinct aspects of deformation and fracture during indentations. In particular, we develop an approach to verification of nanoindentation induced film fracture in hard film/soft substrate systems; we examine the ability to perform these experiments in harsh environments; we investigate the methods by which the resulting deformation from indentation can be quantified and correlated to computational simulations, and we examine the onset of plasticity during indentation testing. First, nanoindentation was utilized to induce fracture of brittle thin oxide films on compliant substrates. During the indentation, a load is applied and the penetration depth is continuously measured. A sudden discontinuity, indicative of film fracture, was observed upon the loading portion of the load-depth curve. The mechanical properties of thermally grown oxide films on various substrates were calculated using two different numerical methods. The first method ...

2005-11-01

80

Transient enhanced diffusion from decaborane molecular ion implantation  

Energy Technology Data Exchange (ETDEWEB)

Transient enhanced diffusion (TED) from implantation of 5thinspkeVthinspB{sub 10}H{sub 14} and 0.5 keV B ions has been quantified and compared for nominal boron doses of 10{sup 14} and 10{sup 15}thinspcm{sup {minus}2}. Boron diffusivity during annealing was extracted from secondary ion mass spectroscopy depth profiles of diffused marker layers in boron doping-superlattices and the actual implanted B dose was independently measured by nuclear reaction analysis. Comparable enhancements were observed from both ions. Transmission electron microscopy analysis revealed that both boron- and decaborane-implanted samples were amorphized at a nominal 10{sup 15}thinspcm{sup {minus}2}thinspB dose. A comparison with data from low energy Si implants revealed a similar dependence of diffusivity enhancement on implant dose. These findings are consistent with the understanding that TED is caused by the interstitial supersaturation resulting from a number of ...

1998-10-01

81

Transient enhanced diffusion from decaborane molecular ion implantation  

International Nuclear Information System (INIS)

Transient enhanced diffusion (TED) from implantation of 5keVB_1_0H_1_4 and 0.5 keV B ions has been quantified and compared for nominal boron doses of 10"1"4 and 10"1"5cm"-"2. Boron diffusivity during annealing was extracted from secondary ion mass spectroscopy depth profiles of diffused marker layers in boron doping-superlattices and the actual implanted B dose was independently measured by nuclear reaction analysis. Comparable enhancements were observed from both ions. Transmission electron microscopy analysis revealed that both boron- and decaborane-implanted samples were amorphized at a nominal 10"1"5cm"-"2B dose. A comparison with data from low energy Si implants revealed a similar dependence of diffusivity enhancement on implant dose. These findings are consistent with the understanding that TED is caused by the interstitial supersaturation resulting from a number of excess interstitials approximately equal to the number of implanted atoms ...

1998-10-01

82

The glacial inception as recorded in the NorthGRIP Greenland ice core: timing, structure and associated abrupt temperature changes  

Energy Technology Data Exchange (ETDEWEB)

The mechanisms involved in the glacial inception are still poorly constrained due to a lack of high resolution and cross-dated climate records at various locations. Using air isotopic measurements in the recently drilled NorthGRIP ice core, we show that no evidence exists for stratigraphic disturbance of the climate record of the last glacial inception ({proportional_to}123-100 kyears BP) encompassing Dansgaard-Oeschger events (DO) 25, 24 and 23, even if we lack sufficient resolution to completely rule out disturbance over DO 25. We quantify the rapid surface temperature variability over DO 23 and 24 with associated warmings of 10{+-}2.5 and 16{+-}2.5 C, amplitudes which mimic those observed in full glacial conditions. We use records of {delta}{sup 18}O of O{sub 2} to propose a common timescale for the NorthGRIP and the Antarctic Vostok ice cores, with a maximum uncertainty of 2,500 years, and to examine the interhemispheric sequence of events over this period. ...

2006-02-01

83

Modification of surface texture by grinding and polishing lead zirconate titanate ceramics  

Energy Technology Data Exchange (ETDEWEB)

This paper reports that grinding and polishing affected the orientation of 90[degrees] domains at the surface of lead zirconate titanate (PZT) ceramics. This was quantified by using changes in the intensity ratio of the (002) and (200) X-ray reflections. Grinding unpoled PZT with 600-grit SiC paper gave X-ray intensity ratios similar to those of poled material. This implies that 90[degrees] domain realignments had occurred in the near surface region probed by the X-rays. Grinding poled samples with 600-grit SiC further increased the X-ray intensity ratio beyond that caused by poling, indicating that additional surface reorientation of 90[degrees] domains had occurred. The effects of diamond polishing depended on the size of the diamond particles. The use of 6-[mu]m diamond had no effect on the (002)/(200) intensity ratio of either poled or unpoled samples, while polishing with 15- or 45-[mu]m diamond significantly enhanced the 90[degrees] ...

1992-08-01

84

Modification of surface texture by grinding and polishing lead zirconate titanate ceramics  

International Nuclear Information System (INIS)

This paper reports that grinding and polishing affected the orientation of 90 degrees domains at the surface of lead zirconate titanate (PZT) ceramics. This was quantified by using changes in the intensity ratio of the (002) and (200) X-ray reflections. Grinding unpoled PZT with 600-grit SiC paper gave X-ray intensity ratios similar to those of poled material. This implies that 90 degrees domain realignments had occurred in the near surface region probed by the X-rays. Grinding poled samples with 600-grit SiC further increased the X-ray intensity ratio beyond that caused by poling, indicating that additional surface reorientation of 90 degrees domains had occurred. The effects of diamond polishing depended on the size of the diamond particles. The use of 6-#mu#m diamond had no effect on the (002)/(200) intensity ratio of either poled or unpoled samples, while polishing with 15- or 45-#mu#m diamond significantly enhanced the 90 degrees domain ...

1992-01-01

85

Feasibility of delivering grid therapy using a multileaf collimator  

International Nuclear Information System (INIS)

The feasibility of using a multileaf collimator (MLC) for grid therapy is demonstrated in this study. Grids with the projected field openings of 10 mmx10 mm and 5 mmx5 mm were created using multiple MLC-shaped fields. The deposited doses were measured with films at different depths in a solid water phantom and compared to those of Cerrobend grid collimators of similar hole sizes and hole separations. At the depth of maximum dose (d_m_a_x), the valley-to-peak dose ratios of the MLC grids were found to be about 11% and 19% for the respective 10 mmx10 mm and 5 mmx5 mm grid openings, and those of the corresponding grid blocks were about 15% and 20%. To quantify the dose contributed by transmission in the blocked areas due to the limited leaf thickness, Monte Carlo simulations (based on convolution/superposition method) were performed to calculate the doses in the solid water phantom using an ideal MLC with no leakage and perfect divergence in both ...

2006-01-01

86

Exposure to radiation from the natural radioactivity in building materials  

International Nuclear Information System (INIS)

Radiation exposure of members of the public can be increased appreciably by the use of building materials containing above-normal levels of natural radioactivity. This phenomenon has attracted attention in recent years, and in this review, an attempt is made to the quantify exposures incurred under various circumstances. The second section of the review is a general survey of those building materials, mostly industrial wastes, that have aroused interest in Member countries. The probability that environmental pressures may cause such wastes to be used more and more by building industries may lead to similar situations in the future. Other review material of a relevant nature is described in the third section. Primordial radionuclides only are considered here. They are: potassium-40 (K-40); radium-226 (Ra-226) and its decay products; the series headed by thorium-232 (Th-232). The important radiological consequences of the natural radioactivity in ...

2010-05-01

87

Durability of cement-based materials: modeling of the influence of physical and chemical equilibria on the microstructure and the residual mechanical properties; Durabilite des materiaux cimentaires: modelisation de l'influence des equilibres physico-chimiques sur la microstructure et les proprietes mecaniques residuelles  

Energy Technology Data Exchange (ETDEWEB)

A large part of mechanical and durability characteristics of cement-based materials comes from the performances of the hydrated cement, cohesive matrix surrounding the granular skeleton. Experimental studies, in situ or in laboratory, associated to models, have notably enhanced knowledge on the cement material and led to adapted formulations to specific applications or particularly aggressive environments. Nevertheless, these models, developed for precise cases, do not permit to specifically conclude for other experimental conclusions. To extend its applicability domain, we propose a new evolutive approach, based on reactive transport expressed at the microstructure scale of the cement. In a general point of view, the evolution of the solid compounds of the cement matrix, by dissolutions or precipitations, during chemical aggressions can be related to the pore solution evolution, and this one relied to the ionic exchanges with the external environment. By the utilization of a ...

2004-09-15

88

A model for estimating the hydraulic conductivity of granular material based on grain shape, grain size, and porosity  

Energy Technology Data Exchange (ETDEWEB)

Particle shape is an important parameter in numerous civil, environmental, and petroleum engineering applications. In ground-water flow, the shape of individual particles comprising the soil affects the soil`s pore size distribution and, hence, the important flow characteristics such as hydraulic conductivity and headloss. A model for delineating the relative importance of particle size, particle shape, and porosity, (and their interactions), in explaining the variability of hydraulic conductivity of a granular porous medium is developed and tested. Three types of porous media are considered in this work: spherical glass beads; granular sand; and irregularly shaped, shredded glass particles. A reliable method for quantifying the three-dimensional shape and packing of large samples of irregular particles based on their angle of repose is presented. The results of column experiments indicate that in the size range examined (i.e., 149 {micro}m to 2,380 {micro}m), the ...

1995-11-01

89

Modelling the reworking effects of bioturbation on the incorporation of radionuclides into the sediment column: implications for the fate of particle-reactive radionuclides in Irish Sea sediments  

Energy Technology Data Exchange (ETDEWEB)

A microcosm laboratory experiment was conducted to determine the impact of biological reworking by the ragworm Nereis diversicolor on the redistribution of particle-bound radionuclides deposited at the sediment-water interface. Over the course of the 40-day experiment, as much as 35% of a {sup 137}Cs-labelled particulate tracer deposited on the sediment surface was redistributed to depths of up to 11 cm by the polychaete. Three different reworking models were employed to model the profiles and quantify the biodiffusion and biotransport coefficients: a gallery-diffuser model, a continuous sub-surface egestion model and a biodiffusion model. Although the biodiffusion coefficients obtained for each model were quite similar, the continuous sub-surface egestion model provided the best fit to the data. The average biodiffusion coefficient, at 1.8 {+-} 0.9 cm{sup 2} y{sup -1}, is in good agreement with the values quoted by other workers on the ...

2010-11-15

90

Modelling the reworking effects of bioturbation on the incorporation of radionuclides into the sediment column: implications for the fate of particle-reactive radionuclides in Irish Sea sediments  

International Nuclear Information System (INIS)

A microcosm laboratory experiment was conducted to determine the impact of biological reworking by the ragworm Nereis diversicolor on the redistribution of particle-bound radionuclides deposited at the sediment-water interface. Over the course of the 40-day experiment, as much as 35% of a "1"3"7Cs-labelled particulate tracer deposited on the sediment surface was redistributed to depths of up to 11 cm by the polychaete. Three different reworking models were employed to model the profiles and quantify the biodiffusion and biotransport coefficients: a gallery-diffuser model, a continuous sub-surface egestion model and a biodiffusion model. Although the biodiffusion coefficients obtained for each model were quite similar, the continuous sub-surface egestion model provided the best fit to the data. The average biodiffusion coefficient, at 1.8 #+-# 0.9 cm"2 y"-"1, is in good agreement with the values quoted by other workers on the bioturbation ...

2010-11-01

91

Quantifying Risk Factors for Human Brucellosis in Rural Northern Tanzania  

UK PubMed Central (United Kingdom)

BackgroundBrucellosis is a zoonosis of veterinary, public health and economic significance in most developing countries. Human brucellosis is a severely debilitating disease that...Full Text Available

92

In vivo range of motion of the lumbar spinous processes  

UK PubMed Central (United Kingdom)

The study design included an in vivo laboratory study. The objective of the study is to quantify the kinematics of the lumbar spinous processes in asymptomatic patients during un-restricted functional...Full Text Available

2009-09-01

93

A Caution Against Interpreting and Quantifying Oyster Habitat Loss from Historical Surveys  

Science.gov (United States)

... surveys, and increasing interest in both developing an oyster aquaculture industry and scaling up restoration efforts by federal, ... ...

94

Rotation of the bulge components of barred galaxies  

International Nuclear Information System (INIS)

Stellar rotation and velocity-dispersion measurements are presented for the bulge components of the SBO galaxies NGC 1023, 2859, 2950, 4340, 4371, and 7743. The kinematics of nine SB bulges with data available are compared with bulges of unbarred galaxies studied by Kormendy and Illingworth. All of the SB bulges are found to rotate at least as rapidly as oblate-spheroid dynamical models which are flattened by rotation. This result confirms the conclusion of Kormendy and Illingworth that bulges rotate very rapidly. Six SB bulges found by Kormendy and Koo to be triaxial rotate even more rapidly than the oblate models. In this respect, they resemble published n-body models of bars. That is, triaxial bulges are dynamically like bars and unlike elliptical galaxies, which are also believed to be triaxial, but which rotate slowly. Measured velocity anisotropies are found to be consistent with these conclusions. Two ordinary bulges whose rotation is ...

95

Population dynamics of dechlorinators and factors affecting the level and products of PCB dechlorination in sediments  

Energy Technology Data Exchange (ETDEWEB)

Microbial dechlorination of polychlorinated biphenyls (PCBs) often stops although a significant number of removable chlorines remain. To determine the reason for the cessation, we investigated the limitation of organic carbon, PCB bioavailability, and inhibition by metabolic products. Enrichment with carbon sources did not induce additional chlorination, indicating the plateau was not due to depletion of organic carbon. The bioavailability was not limiting, since a subcritical micelle concentration of the surfactant, which enhanced desorption without inhibiting dechlorinating microorganisms, failed to lower the plateau. Neither was it due to accumulation of metabolites, since no additional dechlorination was detected when plateau sediments were incubated with fresh medium. Similarly, dechlorination was not inhibited in freshly spiked sediment slurries. Dechlorination ended up at the same level with nearly identical congener profiles, regardless of treatment. These ...

1996-12-31

96

Influence of anchor behaviour on the earthquake response of liquid storage tanks  

International Nuclear Information System (INIS)

The dynamic response of thin liquid storage tanks to earthquakes is a very complicated phenomenon, because it can be highly non linear. Among others, one can meet material and geometric non linearities of the tank shell leading eventually to static or dynamic buckling non linear behavior of anchor bolts, contact non-linearities due to the uplift of the tank base and to the unilateral character of the fluid pressure on the shell and high amplitude fluid oscillations. Moreover, linear or non linear soil structure interaction affects considerably the response of the fluid structure system under consideration. In this paper we focus attention on problems related only to the base uplift and anchors plastification. We study a tank similar to the Hualien project tank, but we neglect the soil structure interaction. The studied tank is representative of medium height to radius ratio ratio tanks with relatively thick bottom plate. ...

97

Evaluation of the Performance of the Automated NucliSENS easyMAG and EasyQ Systems versus the Roche AmpliPrep-AMPLICOR Combination for High-Throughput Monitoring of Human Immunodeficiency Virus Load?  

Science.gov (United States)

This study presents the data of an evaluation of the automated Nuclisens easyMAG and EasyQ systems versus the Roche AmpliPrep-AMPLICOR combination for testing of high-volume human immunodeficiency virus (HIV) load. This represents a follow-up of a previous study investigating the performance of the real-time Nuclisens assay using the semiautomated NucliSENS miniMAG extraction procedure. Three hundred eighteen patient samples were analyzed using both methods. The easyMAG-EasyQ HIV type 1 system has a higher sensitivity and broader dynamic range than the Cobas AmpliPrep-AMPLICOR system when the standard Roche assay is used alone, 25 to 3,000,000 IU/ml versus 400 to 750,000 HIV RNA copies/ml, respectively. There was significant correlation between the assays (0.93; P < 0.0001), with good accuracy (percent similarity mean ? = 96%), good precision (percent similarity standard deviation = 4.97%), and overall good agreement ...

2007-05-01

98

DOC, Color and Disinfection By-Product Precursor Dynamics along an Urbanization Gradient, Croton Water Supply System, New York, USA  

Science.gov (United States)

Hydrologic processes in suburban watersheds and their effects on water quality warrant investigation. Biweekly and storm samples were collected and analyzed for base cations, selected anions, and DOC over a one-year period at the outlet of three small (37 - 55 ha) watersheds (one forested, two with different degrees of suburban development) in the Croton Watershed, southeastern New York. Less frequent sampling for Pt/Co color and disinfection by-product precursors (DBPs) were also conducted. Median baseflow concentrations (>3 days since rainfall) of DOC were similar, ranging from 2.1 to 1.8 to 1.7 mg L -1 for the most urbanized to the forested watershed, respectively. On a unit area load basis (kg ha-1 yr-1), the range was from 8.9 to 6.4 to 5.1, again from most urbanized to forested watershed. All three watersheds showed similar storm responses, with evidence for a flushing mechanism in that DOC concentration increased with increasing ...

2005-05-01

99

Dynamic Virtual LANs for Adaptive Network Security  

Science.gov (United States)

Page 1. Dynamic Virtual LANs for Adaptive Network Security ... Dynamic Virtual LANs for adaptive network security D. Merani, A. Berni, M. Leonard ...

2004-11-01

105

Dynamic Analysis and Qualification Test of Nuclear Components.  

Science.gov (United States)

This report contains the study on the dynamic characteristics of Wolsung fuel rod and on the dynamic balancing of rotating machinery to evaluate the performance of nuclear reactor components. The study on the dynamic characteristics of Wolsung fuel rod wa...

1981-01-01

107

Three-dimensional simulation study of compact toroid plasmoid injection into magnetized plasmas  

Energy Technology Data Exchange (ETDEWEB)

Three-dimensional dynamics of a compact toroid (CT) plasmoid, which is injected into a magnetized target plasma region is investigated by using magnetohydrodynamic (MHD) numerical simulations. It is found that the process of the CT penetration into this region is much more complicated than what has been analyzed so far by using a conducting sphere (CS) model. The injected CT suffers from a tilting instability, which grows with the similar time scale as the CT penetration. The instability is accompanied by magnetic reconnection between the CT magnetic field and the target magnetic field, which disrupts the magnetic configuration of the CT. Magnetic reconnection plays a role to supply the high density plasma initially confined in the CT magnetic field into the target region. Also, the penetration depth of the CT high density plasma is examined. It is shown to be shorter than that estimated from the CS model. The CT high density plasma is ...

1999-04-01

108

The detection of spiral arm modulation in the stellar disk of an optically flocculent and an optically grand design galaxy  

CERN Document Server

Two dimensional Fourier spectra of near-infrared images of galaxies provide a powerful diagnostic tool for the detection of spiral arm modulation in stellar disks. Spiral arm modulation may be understood in terms of interference patterns of outgoing and incoming density wave packets or modes. The brightness along a spiral arm will be increased where two wave crests meet and constructively interfere, but will be decreased where a wave crest and a wave trough destructively interfere. Spiral arm modulation has hitherto only been detected in grand design spirals (such as Messier 81). Spiral arm amplitude variations have the potential to become a powerful constraint for the study of galactic dynamics. We illustrate our method in two galaxies: NGC 4062 and NGC 5248. In both cases, we have detected trailing and leading m=2 waves with similar pitch angles. This suggests that the amplification mechanism is the WASER type II. In this mechanism, the bulge ...

2000-01-01

109

The Performance of Spent Fuel Casks in Severe Tunnel Fires  

International Nuclear Information System (INIS)

The Nuclear Regulatory Commission (NRC), working with the National Institute of Standards and Technology (NIST), Pacific Northwest National Laboratory (PNNL), and the National Transportation Safety Board (NTSB), performed analyses to predict the response of various spent fuel transportation cask designs when exposed to a fire similar to that which occurred in the Howard Street railroad tunnel in downtown Baltimore, Maryland on July 18, 2001. The thermal performance of three different spent fuel cask designs (HOLTEC HI-STAR 100, TransNuclear TN-68, and NAC-LWT) was evaluated with the ANSYSR and COBRA-SFS analysis codes, utilizing boundary conditions for the tunnel fire obtained using NIST's Fire Dynamics Simulator (FDS) code. NRC Staff evaluated the potential for a release of radioactive material from each of the three transportation casks analyzed for the Baltimore tunnel fire scenario. The results of these analyses are described in detail in ...

2005-11-01

110

TRANS-NEPTUNIAN OBJECTS WITH HUBBLE SPACE TELESCOPE ACS/WFC  

International Nuclear Information System (INIS)

We introduce a novel search technique that can identify trans-Neptunian objects in three to five exposures of a pointing within a single Hubble Space Telescope (HST) orbit. The process is fast enough to allow the discovery of candidates soon after the data are available. This allows sufficient time to schedule follow-up observations with HST within a month. We report the discovery of 14 slow-moving objects found within 50 of the ecliptic in archival data taken with the Wide Field Channel of the Advanced Camera for Surveys. The luminosity function of these objects is consistent with previous ground-based and space-based results. We show evidence that the size distribution of both high and low inclination populations is similar for objects smaller than 100 km, as expected from collisional evolution models, while their size distribution differs for brighter objects. We suggest that the two populations formed in different parts of the protoplanetary disk and after ...

2010-10-20

111

THE EVOLUTION OF CLOUD CORES AND THE FORMATION OF STARS  

International Nuclear Information System (INIS)

For a number of starless cores, self-absorbed molecular line and column density observations have implied the presence of large-amplitude oscillations. We examine the consequences of these oscillations on the evolution of the cores and the interpretation of their observations. We find that the pulsation energy helps support the cores and that the dissipation of this energy can lead toward instability and star formation. In this picture, the core lifetimes are limited by the pulsation-decay timescales, dominated by non-linear mode-mode coupling, and on the order of #approx =# few x 10"5-10"6 yr. Notably, this is similar to what is required to explain the relatively low rate of conversion of cores into stars. For cores with large-amplitude oscillations, dust continuum observations may appear asymmetric or irregular. As a consequence, some of the cores that would be classified as super-critical may be dynamically stable when oscillations are taken ...

2010-09-20

112

Paul Trap Simulator Experiment to Model Intense Beam Propagation in Alternating-gradient Transport Systems  

Energy Technology Data Exchange (ETDEWEB)

The results presented here demonstrate that the Paul Trap Simulator Experiment (PTSX) simulates the propagation of intense charged particle beams over distances of many kilometers through magnetic alternating-gradient (AG) transport systems by making use of the similarity between the transverse dynamics of particles in the two systems. Plasmas have been trapped that correspond to normalized intensity parameters s = wp2 (0)/2wq2 * 0.8, where wp(r) is the plasmas frequency and wq is the average transverse focusing frequency in the smooth-focusing approximation. The measured root-mean-squared (RMS) radius of the beam is consistent with a model, equally applicable to both PTSX and AG systems that balances the average inward confining force against the outward pressure-gradient and space-charge forces. The PTSX device confines one-component cesium ion plasmas for hundreds of milliseconds, which is equivalent to over 10 km of beam propagation.

2004-01-29

113

NATIONAL HIGH MAGENTIC FIELD LABORATORY FEL INJECTOR DESIGN CONSIDERATION  

Energy Technology Data Exchange (ETDEWEB)

A Numerical study of beam dynamics was performed for two injector systems for the proposed National High Magnetic Field Laboratory at the Florida State University (FSU) Free Electron Laser (FEL) facility. The first considered a system consisting of a thermionic DC gun, two buncher cavities operated at 260 MHz and 1.3 GHz and two TESLA type cavities, and is very similar to the injector of the ELBE Radiation Source. The second system we studied uses a DC photogun (a copy of JLab FEL electron gun), one buncher cavity operated at 1.3 GHz and two TESLA type cavities. The study is based on PARMELA simulations and takes into account operational experience of both the JLab FEL and the Radiation Source ELBE. The simulations predict the second system will have a much smaller longitudinal emittance. For this reason the DC photo gun based injector is preferred for the proposed FSU FEL facility.

2007-06-25

114

Multidimensional two-phase flow regime distribution in a PWR downcomer during an LBLOCA refill phase  

Energy Technology Data Exchange (ETDEWEB)

The multidimensional countercurrent two-phase flow regimes that occur in a pressurized-water reactor (PWR) vessel downcomer during the refill phase of a large-break loss-of-coolant accident are studied using a transparent 1/10 scale model of a PWR vessel. The various flow regimes and their distribution in the downcomer have been identified and mapped for a range of air-water flooding experiments. The two-phase flow patterns that are identified in the downcomer included various types of film flows, droplet flows, countercurrent churn flows and cocurrent flows depending on the flooding condition. Through observation of the two-phase flow dynamics it was deduced that the physical mechanisms associated with the flooding processes could be separated into a liquid entrainment process and a film flow reversal process. In addition to the above exercise, the effect of non-uniform injection of water into the downcomer via different combinations of cold leg was studied ...

1994-09-01

115

Multidimensional two-phase flow regime distribution in a PWR downcomer during an LBLOCA refill phase  

International Nuclear Information System (INIS)

The multidimensional countercurrent two-phase flow regimes that occur in a pressurized-water reactor (PWR) vessel downcomer during the refill phase of a large-break loss-of-coolant accident are studied using a transparent 1/10 scale model of a PWR vessel. The various flow regimes and their distribution in the downcomer have been identified and mapped for a range of air-water flooding experiments. The two-phase flow patterns that are identified in the downcomer included various types of film flows, droplet flows, countercurrent churn flows and cocurrent flows depending on the flooding condition. Through observation of the two-phase flow dynamics it was deduced that the physical mechanisms associated with the flooding processes could be separated into a liquid entrainment process and a film flow reversal process. In addition to the above exercise, the effect of non-uniform injection of water into the downcomer via different combinations of cold leg was studied ...

1993-10-01

116

Modeling of a horizontal steam generator for the submerged nuclear power station concept  

Energy Technology Data Exchange (ETDEWEB)

A submerged nuclear power station has been proposed as an alternative power station with a relatively low environmental impact for use by both industrialized and developing countries. The station would be placed 10 m above the seabed at a depth of 30--100 m and a distance of 10--30 km from shore. The submerged nuclear power station would be manufactured and refueled in a central facility, thus gaining the economies of factoryfabrication and the flexibility of short-lead-time deployment. To minimize the size of the submerged hull, horizontal steam generators are proposed for the primary-to-secondary heat transfer, instead of the more traditional vertical steam generators. The horizontal steam generators for SNPS would be similar in design to the horizontal steam generators used in the N-Reactors except the tube orientation is horizontal (the tube's inlet and outlet connection points on the tubesheet are at the same elevation). Previous RELAP5 input decks ...

1993-01-01

117

Modeling of a horizontal steam generator for the submerged nuclear power station concept  

Energy Technology Data Exchange (ETDEWEB)

A submerged nuclear power station has been proposed as an alternative power station with a relatively low environmental impact for use by both industrialized and developing countries. The station would be placed 10 m above the seabed at a depth of 30--100 m and a distance of 10--30 km from shore. The submerged nuclear power station would be manufactured and refueled in a central facility, thus gaining the economies of factoryfabrication and the flexibility of short-lead-time deployment. To minimize the size of the submerged hull, horizontal steam generators are proposed for the primary-to-secondary heat transfer, instead of the more traditional vertical steam generators. The horizontal steam generators for SNPS would be similar in design to the horizontal steam generators used in the N-Reactors except the tube orientation is horizontal (the tube`s inlet and outlet connection points on the tubesheet are at the same elevation). Previous RELAP5 input decks for ...

1993-05-01

118

Modeling of a horizontal steam generator for the submerged nuclear power station concept  

International Nuclear Information System (INIS)

A submerged nuclear power station has been proposed as an alternative power station with a relatively low environmental impact for use by both industrialized and developing countries. The station would be placed 10 m above the seabed at a depth of 30--100 m and a distance of 10--30 km from shore. The submerged nuclear power station would be manufactured and refueled in a central facility, thus gaining the economies of factoryfabrication and the flexibility of short-lead-time deployment. To minimize the size of the submerged hull, horizontal steam generators are proposed for the primary-to-secondary heat transfer, instead of the more traditional vertical steam generators. The horizontal steam generators for SNPS would be similar in design to the horizontal steam generators used in the N-Reactors except the tube orientation is horizontal (the tube's inlet and outlet connection points on the tubesheet are at the same elevation). Previous RELAP5 input decks for ...

1993-07-06

119

MARS CODE MANUAL VOLUME V: Models and Correlations  

International Nuclear Information System (INIS)

Korea Advanced Energy Research Institute (KAERI) conceived and started the development of MARS code with the main objective of producing a state-of-the-art realistic thermal hydraulic systems analysis code with multi-dimensional analysis capability. MARS achieves this objective by very tightly integrating the one dimensional RELAP5/MOD3 with the multi-dimensional COBRA-TF codes. The method of integration of the two codes is based on the dynamic link library techniques, and the system pressure equation matrices of both codes are implicitly integrated and solved simultaneously. In addition, the Equation-Of-State (EOS) for the light water was unified by replacing the EOS of COBRA-TF by that of the RELAP5. This models and correlations manual provides a complete list of detailed information of the thermal-hydraulic models used in MARS, so that this report would be very useful for the code users. The overall structure of the manual is modeled on the structure of the ...

2002-09-01

120

Low-temperature radiation controlled diffusion of palladium and platinum in silicon for advanced lifetime control  

International Nuclear Information System (INIS)

Radiation defects produced by helium implantation were used to shape profiles of palladium (Pd) and platinum (Pt) atoms in-diffusing (for 20 min at temperatures 600-800 deg. C) either from surface silicide (Pd_2Si, PtSi) or implanted layers. Results show that this procedure allows a strong localization of substitutional Pd and Pt at the depth where the damage produced by helium peaks. This results in local reduction of carrier lifetime by an almost ideal recombination centers - the acceptor level of substitutional Pd (E _c - 0.22 eV) or Pt (E _c - 0.23 eV). While optimum conditions for Pt in-diffusion are about 700 deg. C, Pd gives the best results already at lower temperatures (600 deg. C) where it also exhibits higher peak solubility. Both methods were used for optimization of turn-off properties of high power PiN diodes. The devices, where the lifetime was killed locally by Pd and Pt, exhibited similar trade-off between the static and ...

2006-12-01

121

Investigating long-range correlation properties in EEG during complex cognitive tasks  

Energy Technology Data Exchange (ETDEWEB)

Previous work shows the presence of scale invariance and long-range correlations in ongoing and spontaneous activity of large scale brain responses (i.e. EEG), and such scaling behavior can also be modulated by simple sensory stimulus. However, little is known whether such alteration but not destruction in scaling properties also occurs during complex cognitive processing and if neuroplasticity plays any role in mediating such changes. In this study, we addressed these issues by investigating scaling properties of multivariate EEG signals obtained from two broad groups - artists and non-artists - while they performed complex tasks of perception and mental imagery of visual art objects. We found that brain regions showing increased correlation properties from rest were similar for both tasks, suggesting that brain networks responsible for visual perception are reactivated for mental imagery. Further, we observed that the two groups could be differentiated by scaling ...

2009-11-30

122

Inf-convolution of g_\\Gamma-solution and its applications  

CERN Document Server

A risk-neutral method is always used to price and hedge contingent claims in complete market, but another method based on utility maximization or risk minimization is wildly used in more general case. One can find all kinds of special risk measure in literature. In this paper, instead of using market modified risk measure, we use a kind of risk measure induced by g_\\Gamma-solution or the minimal solution of a Constrained Backward Stochastic Differential Equation (CBSDE) directly when constraints on wealth and portfolio process comes to our consideration. Such g_\\Gamma-solution and the risk measure generated by it is well defined on appropriate space under suitable conditions. We adopt the inf-convolution of convex risk measures to solve some optimization problem. A dynamic version risk measures defined through g_\\Gamma-solution and some similar results about optimal problem can be got in our new framework and by our new approach.

2011-01-01

123

High resolution scanning electron microscopy of plasmodesmata.  

Science.gov (United States)

Symplastic transport occurs between neighbouring plant cells through functionally and structurally dynamic channels called plasmodesmata (PD). Relatively little is known about the composition of PD or the mechanisms that facilitate molecular transport into neighbouring cells. While transmission electron microscopy (TEM) provides 2-dimensional information about the structural components of PD, 3-dimensional information is difficult to extract from ultrathin sections. This study has exploited high-resolution scanning electron microscopy (HRSEM) to reveal the 3-dimensional morphology of PD in the cell walls of algae, ferns and higher plants. Varied patterns of PD were observed in the walls, ranging from uniformly distributed individual PD to discrete clusters. Occasionally the thick walls of the giant alga Chara were fractured, revealing the surface morphology of PD within. External structures such as spokes, spirals and mesh were observed surrounding the PD. ...

2011-05-28

124

HST/ACS observations of shell galaxies: inner shells, shell colours and dust  

CERN Document Server

AIM:Learn more about the origin of shells and dust in early type galaxies. METHOD: V-I colours of shells and underlying galaxies are derived, using HST Advanced Camera for Surveys (ACS) data. A galaxy model is made locally in wedges and subtracted to determine shell profiles and colours. We applied Voronoi binning to our data to get smoothed colour maps of the galaxies. Comparison with N-body simulations from the literature gives more insight to the origin of the shell features. Shell positions and dust characteristics are inferred from model galaxy subtracted images. RESULT: The ACS images reveal shells well within the effective radius in some galaxies (at 1.7 kpc in the case of NGC 5982). In some cases, strong nuclear dust patches prevent detection of inner shells. Most shells have colours which are similar to the underlying galaxy. Some inner shells are redder than the galaxy. All six shell galaxies show out of dynamical equilibrium dust ...

2007-01-01

125

Evaluating Systematic Dependencies of Type Ia Supernovae: The Influence of Progenitor Ne22 Content on Dynamics  

CERN Document Server

We present a theoretical framework for formal study of systematic effects in Supernovae Type Ia (SN Ia) that utilizes 2-d simulations to implement a form of the deflagration-detonation transition (DDT) explosion scenario. The framework is developed from a randomized initial condition that leads to a sample of simulated SN Ia whose Ni56 masses have a similar average and range to those observed, and have many other modestly realistic features such as the velocity extent of intermediate mass elements. The intended purpose is to enable statistically well-defined studies of both physical and theoretical parameters of the SN Ia explosion simulation. We present here a thorough description of the outcome of the SN Ia explosions produced by our current simulations. A first application of this framework is utilized to study the dependence of the SN Ia on the Ne22 content, which is known to be directly influenced by the progenitor stellar population's metallicity. Our study ...

2009-01-01

126

Emissions of nitrogen oxides from equatorial rain forest in central Africa: origin and regulation of NO emission from soils  

Energy Technology Data Exchange (ETDEWEB)

Emissions of nitric oxide from soils of equatorial rain forest were measured in the Dimonika Natural Park (4 degrees 30'S, 12 degrees 30'E) in the Mayombe Forest in Congo. Three research campaigns were carried out in June and July 1991 and in February 1992. Fluxes were measured by dynamic chamber techniques using a chemiluminescence instrument Scintrex LMA3. NO fluxes measured on natural soils are in between 5 and 17x10[sup 9] molecules cm[sup -2]s[sup -1]; they are of the same order of magnitude as those observed in similar tropical forest media. Soil treatment experiments show that the auto-decomposition of HNO[sub 2] in these acid soils (pH 4) (chemodenitrification) is a potentially important cause of nitric oxide production in this type of ecosystem. Nitrous acid comes from autotrophic nitrification all the year around, and also from biological denitrification, shown by N[sub 2]O emissions, during the rainy season. The ...

1994-09-01

127

Effect of velocity variation on secondary-ion-emission probability: Quantum stationary approach  

Energy Technology Data Exchange (ETDEWEB)

The ion-velocity dependence of the ionization probability for an atom ejected from a surface is examined by using a quantum approach in which the coupled motion between electrons and the outgoing nucleus is followed along the whole trajectory by solving the stationary Schroedinger equation. We choose a very-small-cluster-model system in which the motion of the atom is restricted to one dimension, and with energy potential curves corresponding to the involved channels varying appreciably with the atom position. We found an exponential dependence on the inverse of the asymptotic ion velocity for high emission energies, and a smoother behavior with slight oscillations at low energies. These results are compared with those obtained within a dynamical-trajectory approximation using either a constant velocity equal to the asymptotic ionic value, or expressions for the velocity derived from the eikonal approximation and from the classical limit of the current vector. Both ...

1989-11-01

128

Diffractive deep inelastic scattering in an AdS/CFT inspired model: A phenomenological study  

International Nuclear Information System (INIS)

The analytical treatment of the nonperturbative QCD dynamics is one of the main open questions of the strong interactions. Currently, it is only possible to get some qualitative information about this regime considering other QCD-like theories, as, for example, the N=4 super Yang-Mills theory, where one can perform calculations in the nonperturbative limit of large 't Hooft coupling using the anti-de Sitter space/conformal field theory (AdS/CFT). Recently, the high energy scattering amplitude was calculated in the AdS/CFT approach, applied to deep-inelastic scattering and confronted with the F_2 HERA data. In this work we extend the nonperturbative AdS/CFT inspired model for diffractive processes and compare its predictions with a perturbative approach based on the Balitsky-Kovchegov equation. We demonstrate that the AdS/CFT inspired model is not able to describe the current F_2"D"("3") HERA data and predicts a similar behavior to that from the ...

2010-05-01

129

Crystalline beam ground state  

Energy Technology Data Exchange (ETDEWEB)

In order to employ molecular dynamics (MD) methods, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations using MD methods has been performed to obtain the equilibrium crystalline beam structure. The effect of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time dependent. The ground state is a zero entropy state, despite the time-dependent, ...

1993-06-11

130

Cosmological Hydrodynamics with Adaptive Mesh Refinement a new high resolution code called RAMSES  

CERN Document Server

A new N-body and hydrodynamical code, called RAMSES, is presented. It has been designed to study structure formation in the universe with high spatial resolution. The code is based on Adaptive Mesh Refinement (AMR) technique, with a tree based data structure allowing recursive grid refinements on a cell-by-cell basis. The N-body solver is very similar to the one developed for the ART code (Kravtsov et al. 97), with minor differences in the exact implementation. The hydrodynamical solver is based on a second-order Godunov method, a modern shock-capturing scheme known to compute accurately the thermal history of the fluid component. The accuracy of the code is carefully estimated using various test cases, from pure gas dynamical tests to cosmological ones. The specific refinement strategy used in cosmological simulations is described, and potential spurious effects associated to shock waves propagation in the resulting AMR grid are discussed and ...

2001-01-01

131

BARBOX: An alternative system concept for floating production, storage, and offloading  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the Brown and Root`s BARBOX, an alternative, purpose-built, deep-draft monohull system for floating production, storage, and offloading (FPSO). This alternative system concept has been designed for worldwide applications including the North Sea and the Gulf of Mexico environments. The stiffened flat plate construction of the BARBOX gives it a low capital investment cost relative to minimum water plane hull types (e.g., semi-submersible, SPAR, TLP) and ship-shaped FPSO. Dynamic motion comparison between the BARBOX and the ship-shaped FPSO indicates that the BARBOX`s motion characteristics are similar or better than those of comparable ship-shaped FPSO configurations. This paper also considers construction of the BARBOX hull in the Gulf of Mexico region. A recent study indicated that the Gulf coast fabrication yards were technically capable to fabricate the BARBOX hull and they could be cost competitive against worldwide ...

1997-07-01

132

Initiation of depleted uranium oxide and spent fuel testing for the spent fuel sabotage aerosol ratio program  

Energy Technology Data Exchange (ETDEWEB)

We provide a detailed overview of an ongoing, multinational test program that is developing aerosol data for some spent fuel sabotage scenarios on spent fuel transport and storage casks. Experiments are being performed to quantify the aerosolized materials plus volatilized fission products generated from actual spent fuel and surrogate material test rods, due to impact by a high energy density device, HEDD. The program participants in the U.S. plus Germany, France, and the U.K., part of the international Working Group for Sabotage Concerns of Transport and Storage Casks, WGSTSC have strongly supported and coordinated this research program. Sandia National Laboratories, SNL, has the lead role for conducting this research program; test program support is provided by both the U.S. Department of Energy and Nuclear Regulatory Commission. WGSTSC partners need this research to better understand potential radiological impacts from sabotage of nuclear material shipments and ...

2004-07-01

133

The use of oxygen isotopic composition to study water dynamics in Amazon floodplain lakes  

International Nuclear Information System (INIS)

The lakes formed in the Amazon floodplain play a key role in sustaining the highest populational density in the Amazon Basin because of its high primary productivity. The water volume in these lakes vary greatly during the year and possible water sources are the feeding river during high water state of the hydrographs and local inputs from its drainage basin. As these sources are chemically distinct, to understand the nutrient dynamics in these lakes, it is very important to know the relative water contribution of different water sources. In this paper we use "1"8O as a conservative to know the water sources for the lakes and our hypothesis is that: 1) In the high water stage lake water is derived predominantly from its feeding river. Therefore their #delta#"1"8O should be similar. 2) In the low water stage lake water is a mixture of watershed and last flood event waters. In this case, lake #delta#"1"8O should be indicative of the relative ...

1989-05-01

134

Scale model study of pile foundations under earthquake excitation  

Energy Technology Data Exchange (ETDEWEB)

Similitude theory is used to develop scale models for determining the earthquake response of pile foundations embedded in overconsolidated clay. The model is compared with full-scale foundations embedded in natural soil, for which dynamic response measurements had been made in previous work. Correlation of the model and prototype earthquake response constitutes a major difference in this work over previous efforts using scale models. Gravity effects are included in the models by scaling pile and soil material properties. The model pile material is selected to provide the correctly scaled stiffness and mass properties. The required model soil properties are achieved by developing a mixture of bentonite, aerosil, and veegum. Elastic properties of the model soil are compared with those of the prototype by standard monotonic stress and cyclic stress soil tests. It is found that scaling considerations must also apply to supporting static soil tests for determining soil ...

1993-03-01

135

Growth dynamics and biomass production in short-rotation poplar plantations: 6-year results for three clones at four spacings  

Energy Technology Data Exchange (ETDEWEB)

Growth dynamics and biomass production in short-rotation poplar plantations were evaluated at Hanyuan Forestry Farm, Baoying County, P.R.C. Experimental treatments applied in a split-plot design included: four planting densities (1111, 833, 625 and 500 stems ha{sup -1}); three poplar clones (NL-80351, I-69 and I-72) and three rotation lengths. Survival of all three clones was excellent at the experimental site under the imposed management regime. Differences in DBH, height, LAI and above-ground biomass production, however, were manifested among the treatments. Overall the clonal ranking was in the order NL-80351 {>=}I-69 > I-72 by age 6. LAI values ranged from 0.6 to 4.4 m{sup 2} m{sup -2} and differences among four planting densities and three clones were significant throughout the first six years. Above-ground biomass productivity was affected considerably by planting density, clone and rotation length. Within the four densities, the highest biomass ...

1999-07-01

136

Damping properties of sequoia and birch under shock loading  

International Nuclear Information System (INIS)

The decrease mechanic effect on loads being transported, shock load limiters (dampers) are being widely used today. Usually, the materials having 'stress-strain' diagrams (#sigma#-#epsilon#) of compression with a substantial portion, where #sigma# = const., are used as dampers. Most widely used are dampers made of foam polystyrene having just the same compression diagram. Similar strain diagrams can be enlisted for some porous materials, timber under cross compression, perforated metallic crushers and some others. By selecting damper material, the level of transmitted to the protected object pressures can be varied from several to hundreds MPa. Timber, as being widely used and featuring good technologic properties together with low cost, becomes an attractive material to be used as the limiter of shock loads. This paper presents the results of stress-strain sequoia properties (USA deliverable) and birch properties (Volgo-Vyatski region) at ...

1998-05-10

137

Safety calculation for an underground repository for radioactive waste: the first objective of the alliances calculation software platform  

International Nuclear Information System (INIS)

The aim of the safety calculation is to quantify through numerical modelling the radiological impact (molar flow, human dose) of a potential repository for radioactive waste on the Meuse/Haute Marne site at Bure. A selection process is underway for safety scenarios and their phenomenological and numerical conceptual models upstream from the safety calculation. This involves defining and quantifying the geometric and dimensional representations of the repository for each scenario plus the physical, mathematical and numerical models that reflect its behaviour and the uncertainties associated with all the parameters required to quantify the impact. A summary will be given of these various aspects. The numerical simulations are then performed on the Alliances platform which integrates the various computer codes required for the physical representation of the system. (authors)

2005-03-14

138

Efficient methodologies for sensitive HIV-1 RNA quantitation from plasma and vaginal secretions  

British Library Electronic Table of Contents (United Kingdom)

Background: Quantifying HIV levels in mucosal secretions is essential to study compartmentalized expression of HIV and facilitate development of intervention strategies to prevent disease progression and transmission. Objectives: To develop a sensitive, reliable, and cost-effective technique to quantify HIV from blood and vaginal secretions that is compatible with efficient implementation in clinical research environments. Study design: A sensitive, reliable, internally-controlled real-time reverse transcriptase (RT) PCR assay, which uses the HIV-1 pol gene as a target (Hpol assay) was developed to quantify HIV levels in plasma and genital secretions, and compared to the widely used Roche Amplicor(TM) HIV-1 Monitor assay. In addition, a simplified method of sample collection and processing...

2009-01-01

139

Characterization and uncertainty analysis of VOCs emissions from industrial wastewater treatment plants  

British Library Electronic Table of Contents (United Kingdom)

Air toxics from the industrial wastewater treatment plants (IWTPs) impose serious health concerns on its surrounding residential neighborhoods. To address such health concerns, one of the key challenges is to quantify the air emissions from the IWTPs. The objective here is to characterize the air emissions from the IWTPs and quantify its associated uncertainty. An IWTP receiving the wastewaters from an airplane maintenance facility is used for illustration with focus on the quantification of air emissions for benzyl alcohol, phenol, methylene chloride, 2-butanone, and acetone. Two general fate models, i.e., WATER9 and TOXCHEM+V3.0 were used to model the IWTP and quantify the air emissions. Monte Carlo and Bootstrap simulation were used for uncertainty analysis. On average, air emissions fr...

2010-01-01

140

Xylem Embolism in Response to Freeze-Thaw Cycles and Water Stress in Ring-Porous, Diffuse-Porous, and Conifer Species 1  

UK PubMed Central (United Kingdom)

Vulnerability to xylem embolism by freeze-thaw cycles and water stress was quantified in ring-porous (Quercus gambelii Nutt.), diffuse-porous (Populus tremuloides Michx.,...Full Text Available

1992-10-01

141

Variability In Motor Learning: Relocating, Channeling and Reducing Noise  

UK PubMed Central (United Kingdom)

Variability in motor performance decreases with practice but is never entirely eliminated, due in part to inherent motor noise. The present study develops a method that quantifies how performers...Full Text Available

2009-02-01

142

Transcription induces strand-specific mutations at the 5? end of human genes  

UK PubMed Central (United Kingdom)

A regional analysis of nucleotide substitution rates along human genes and their flanking regions allows us to quantify the effect of mutational mechanisms associated with transcription in germ line...Full Text Available

2008-08-01

143

Three-Dimensional Traction Force Microscopy: A New Tool for Quantifying Cell-Matrix Interactions  

UK PubMed Central (United Kingdom)

The interactions between biochemical processes and mechanical signaling play important roles during various cellular processes such as wound healing, embryogenesis, metastasis, and cell migration. While...Full Text Available

144

The effect of maternal anthropometric characteristics and social factors on gestational age and birth weight in Sudanese newborn infants  

UK PubMed Central (United Kingdom)

BackgroundIn Africa low birth weight (LBW) (<2500 g), is the strongest determinant of infant morbidity and mortality. The aim of this study was to quantify the effect of...Full Text Available

145

The Trade-Off between Costs and Outcomes: The Case of Acute Myocardial Infarction  

UK PubMed Central (United Kingdom)

ObjectiveTo investigate and to quantify the relationship between hospital costs and health outcomes for patients with acute myocardial infarction (AMI) in Veterans Health Administration...Full Text Available

2010-12-01

146

Quantifying the accuracy of automated structure segmentation in 4D CT images using a deformable image registration algorithm  

UK PubMed Central (United Kingdom)

Four-dimensional (4D) radiotherapy is the explicit inclusion of the temporal changes in anatomy during the imaging, planning, and delivery of radiotherapy. One key component of 4D radiotherapy planning...Full Text Available

2008-04-01

147

Quantifiable Biomarkers of Normal Aging in the Japanese Medaka Fish (Oryzias latipes)  

UK PubMed Central (United Kingdom)

BackgroundSmall laboratory fish share many anatomical and histological characteristics with other vertebrates, yet can be maintained in large numbers at low cost for lifetime studies....Full Text Available

148

Proteome-wide Anti-HCV and Anti-HIV Antibody Profiling for Predicting and Monitoring Response to HCV Treatment in HIV Co-infected Patients  

UK PubMed Central (United Kingdom)

We quantified antibody responses to the HCV proteome that are associated with sustained virologic response (SVR) in HIV/HCV co-infected patients treated with pegylated interferon and ribavirin....Full Text Available

2010-09-15

149

Prevalence and trends of selected urologic conditions for VA healthcare users  

UK PubMed Central (United Kingdom)

BackgroundConducted as part of the Urologic Diseases in America project whose aim was to quantify the burden of urologic diseases on the American public, this study focuses on Veterans...Full Text Available

150

Predictive Value of Kushida Index and Acoustic Pharyngometry for the Evaluation of Upper Airway in Subjects With or Without Obstructive Sleep Apnea  

UK PubMed Central (United Kingdom)

Acoustic pharyngometry is a relatively new noninvasive method that quantifies geometrically complexed pharyngeal dimensions. Our study aimed to investigate the predictability and usefulness of acoustic...Full Text Available

2004-10-01

151

Predicting Airborne Particle Levels Aboard Washington State School Buses  

UK PubMed Central (United Kingdom)

School buses contribute substantially to childhood air pollution exposures yet they are rarely quantified in epidemiology studies. This paper characterizes fine particulate matter (PM2.5)...Full Text Available

2008-10-01

152

Physical fitness and occupational demands of the Belfast ambulance service.  

UK PubMed Central (United Kingdom)

The objectives of this study were to evaluate the current fitness of an area ambulance service based in Belfast and to quantify the physiological demands of accident and emergency work. From a total...Full Text Available

1991-09-01

153

Physical Morphology and Quantitative Characterization of Chemical Changes of Weathered PVC/Pine Composites.  

Science.gov (United States)

This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifi...

2009-01-01

154

Online quasi-continuous measurement of organic acids in the atmosphere  

Energy Technology Data Exchange (ETDEWEB)

The concentration of some organic acids in the atmosphere was determined using a wet effluent diffusion denuder-aerosol collector coupled with Ion Chromatography. Three organic acids and four inorganic anions were identified and quantified in the air sample, taken from the backyard of PSI. (author)

2002-03-01

155

Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI  

UK PubMed Central (United Kingdom)

Spinal cord injury (SCI) is a debilitating disorder, which produces profound deficits in volitional motor control. Following medical stabilization, recovery from SCI typically involves long term rehabilitation....Full Text Available

156

In situ nanoindentation in a transmission electron microscope  

Science.gov (United States)

This dissertation presents the development of the novel mechanical testing technique of in situ nanoindentation in a transmission electron microscope (TEM). This technique makes it possible to simultaneously observe and quantify the mechanical behavior of nano-scale volumes of solids.

2002-12-02

157

Heritability of Lumbar Trabecular Bone Mechanical Properties in Baboons  

UK PubMed Central (United Kingdom)

Genetic effects on mechanical properties have been demonstrated in rodents, but not confirmed in primates. Our aim was to quantify the proportion of variation in vertebral trabecular bone mechanical...Full Text Available

2010-03-01

158

Evaluation of patients' assessment of day hospital care.  

UK PubMed Central (United Kingdom)

The method of linear analogue self-assessment (LASA) was used to quantify the views concerning day care which were held by patients attending a geriatric day hospital. The results suggest that day hospitals...Full Text Available

1977-09-01

159

Evaluating the Nickel Content in Metal Alloys and the Threshold for Nickel-Induced Allergic Contact Dermatitis  

UK PubMed Central (United Kingdom)

Many patients are currently suffering from nickel (Ni)-induced allergic contact dermatitis (ACD). There have been few Korean studies dealing with the threshold of Ni-induced ACD and quantifying the...Full Text Available

2008-04-01

160

Elevated Levels of Volatile Organic Carcinogen and Toxicant Biomarkers in Chinese Women Who Regularly Cook at Home  

UK PubMed Central (United Kingdom)

BackgroundEpidemiologic studies associate lung cancer in non-smoking Chinese women with Chinese-style wok cooking. Our goal was to quantify carcinogen and toxicant...Full Text Available

2010-05-01

161

Effect of pH and Temperature on Denitrification Gene Expression and Activity in Pseudomonas mandelii?  

UK PubMed Central (United Kingdom)

Pseudomonas mandelii liquid cultures were studied to determine the effect of pH and temperature on denitrification gene expression, which was quantified by quantitative reverse transcription-PCR....Full Text Available

2009-06-01

162

Effect of Breast Milk Lead on Infant Blood Lead Levels at 1 Month of Age  

UK PubMed Central (United Kingdom)

Nursing infants may be exposed to lead from breast milk, but relatively few data exist with which to evaluate and quantify this relationship. This route of exposure constitutes a potential infant hazard...Full Text Available

2004-10-01

163

Detection and Analysis of Tumor Fluorescence Using a Two-Photon Optical Fiber Probe  

UK PubMed Central (United Kingdom)

The utility of a two-photon optical fiber fluorescence probe (TPOFF) for sensing and quantifying tumor fluorescent signals was tested in vivo. Xenograft tumors were developed in athymic mice using MCA207...Full Text Available

2004-06-01

164

Deploying Flowbee Tripod  

USGS Gallery

As part of an investigation of the mechanisms of coastal change in the Carolinas (http://woodshole.er.usgs.gov/project-pages/cccp/index.html), instrumented tripods were deployed on Diamond Shoals near Cape Hatteras, NC. These tripods recorded data quantifying the currents, waves, turbidity, temperat...

2010-01-26

165

Comparison of Optical and SEM BSE Imaging Techniques for Quantifying Alpha-Beta Titanium Alloy Microstructures (Preprint).  

Science.gov (United States)

Quantitative metallography is often used to confirm the proper processing of aerospace metallic materials. A microstructural feature of great importance for titanium alloys processed in the alpha-beta phase field is the volume fraction of primary alpha. S...

2006-01-01

166

Community-based incidence of acute renal failure  

UK PubMed Central (United Kingdom)

There is limited information about the true incidence of acute renal failure (ARF). Most studies could not quantify disease frequency in the general population as they are hospital-based and...Full Text Available

2007-07-01

167

Augmenting Clinical Evaluation of Hemiparetic Arm Movement With a Laboratory-Based Quantitative Measurement of Kinematics as a Function of Limb Loading  

UK PubMed Central (United Kingdom)

BackgroundKinematic and kinetic measurements used in laboratory settings can quantify upper extremity movement impairment following stroke, but their relationship...Full Text Available

2008-01-01

168

Alcohol-folate interactions in women's oral cancer risk: A prospective cohort study  

UK PubMed Central (United Kingdom)

BackgroundThe aim of this cohort study was to quantify the effect of alcohol in the risk of oral cancer in different strata of folate intake, controlling for known...Full Text Available

2010-10-01

169

A field study on the effects of dietary monensin on milk production and milk composition in dairy cows  

UK PubMed Central (United Kingdom)

The objectives of this study were to quantify the effect of 16 ppm of dietary monensin on milk production and composition of dairy cows, and to investigate factors having a potential impact on this...Full Text Available

2010-04-01

170

Dynamic recrystallization behavior of a directionally solidified superalloy  

Energy Technology Data Exchange (ETDEWEB)

This paper investigates the dynamic recrystallization behavior of a directionally solidified (DS) nickel-base superalloy. The dynamic recrystallization occurs after the uncoated superalloy has been tested by tensile creep at elevated temperature for a long time. The dynamic recrystallization temperature is slightly lower than that of the static recrystallization. The dynamic recrystallization behavior of the DS superalloy below the static recrystallization temperature is mainly related to the high temperature oxidation and the free surface. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

2007-10-15

171

Seismic and Rockphysics Diagnostics fo Multiscale Reservoir Textures  

Energy Technology Data Exchange (ETDEWEB)

We have continued to finish up our work on analyzing relationships between elastic properties and rock microstructure. We have worked on theoretical models for the effects of sorting and packing on elastic moduli and seismic velocities. After analyzing the scanning acoustic images of shales to quantify textures at different scales, we are now using theoretical inclusion models to quantify the elastic property variation with texture. In the closing phases of this project most of our efforts are now focused on writing up the results and preparing the final reports.

2005-02-01

172

Correlations in Werner States  

International Nuclear Information System (INIS)

Werner states are paradigmatic examples of quantum states and play an innovative role in quantum information theory. In investigating the correlating capability of Werner states, we find the curious phenomenon that quantum correlations, as quantified by the entanglement of formation, may exceed the total correlations, as measured by the quantum mutual information. Consequently, though the entanglement of formation is so widely used in quantifying entanglement, it cannot be interpreted as a consistent measure of quantum correlations per se if we accept the folklore that total correlations are measured (or rather upper bounded) by the quantum mutual information.

2008-02-15

173

A framework for the financial evaluation of household biogas plants in India  

Energy Technology Data Exchange (ETDEWEB)

A generalised procedure for quantifying the benefits of household biogas plants is presented. The sensitivity of the procedure to the uncertainty in input prices is reduced through the assumption of incremental benefits from the biogas plant. These benefits are quantified in terms of the quantity of fuelwood for which the biogas substitutes in cooking, the quantity of kerosene replaced through the use of biogas for lighting and the diesel fuel displaced through the use of a biogas fuelled dual-fuel engine for motive power. Sensitivity of the monetary benefits for these parameters is examined in order to identify variables which influence the viability of the technology to the end user. (author).

1990-01-01

174

Kokanee Stocking and Monitoring, Flathead Lake, 1993-1994 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

One mitigation goal of the Hungry Horse Dam fisheries mitigation program, funded by the Bonneville Power Administration, is to replace lost production of 100,000 adult kokanee in Flathead Lake. The mitigation program calls for a five-year test to determine if kokanee can be reestablished in Flathead Lake. The test consists. of annual stocking of one million hatchery-raised yearling kokanee. There are three benchmarks for judging the success of the kokanee reintroduction effort: (1) Post-stocking survival of 30 percent of planted kokanee one year after stocking; (2) Yearling to adult survival of 10 percent (100,000 adult salmon); (3) Annual kokanee harvest of 50,000 or more fish per year by 1998, with an average length of 11 inches or longer for harvested fish, and fishing pressure of 100,000 angler hours or more. Kokanee were the primary sport fish species in the Flathead Lake fishery in the early 1900s, and up until the late 1980s when the population rapidly declined in numbers and ...

1995-07-01

175

Study of the Electron Beam Dynamics in the Fermi @ Elettra Linac  

Energy Technology Data Exchange (ETDEWEB)

A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste.

2006-07-19

176

Study of the Electron Beam Dynamics in the FERMI @ ELETTRALinac  

Energy Technology Data Exchange (ETDEWEB)

A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste

2006-06-17

178

Perception and Hierarchical Dynamics  

UK PubMed Central (United Kingdom)

In this paper, we suggest that perception could be modeled by assuming that sensory input is generated by a hierarchy of attractors in a dynamic system. We describe a mathematical model which exploits...Full Text Available

179

Intrapopulation Genome Size Dynamics in Festuca pallens  

UK PubMed Central (United Kingdom)

Background and AimsIt is well known that genome size differs among species. However, information on the variation and dynamics of genome size in wild populations and on the early...Full Text Available

2008-10-01

180

Influence of Pythium oligandrum Biocontrol on Fungal and Oomycete Population Dynamics in the Rhizosphere?  

UK PubMed Central (United Kingdom)

Fungal and oomycete populations and their dynamics were investigated following the introduction of the biocontrol agent Pythium oligandrum into the rhizosphere of tomato plants grown...Full Text Available

2009-07-01

181

Gallbladder function and dynamics of bile flow in asymptomatic gallstone disease  

UK PubMed Central (United Kingdom)

AIM: To investigate the effects of gallbladder stones on motor functions of the gallbladder and the dynamics of bile flow in asymptomatic gallstone disease.METHODS: Quantitative hepatobiliary...Full Text Available

2009-06-14

182

Dynamic clamp with StdpC software  

UK PubMed Central (United Kingdom)

Dynamic clamp is a powerful method that allows the introduction of artificial electrical components into target cells to simulate ionic conductances and synaptic inputs. This method is based...Full Text Available

2011-03-01

183

DYNAMIC ANALYSIS OF DARRIEUS VERTICAL AXIS WIND ...  

Science.gov (United States)

The dynamic response characteristics of the VAWT rotor are important factors governing the safety and fatique life of VAWT systems. The principal problems are ...

184

Active Dynamic Flow Control Studies on Rotor Blades  

Science.gov (United States)

... of the cycle shows that the separation area ea. ... with suitable flow solvers based on the Reynolds ... AGARD 75th Fluid Dynamics Panel Meeting and ...

2001-06-01

185

A Notional Battlespace for Simulating and Testing Dynamic ...  

Science.gov (United States)

... 23 Milstar 25 A Notional Battlespace For Dynamic Wireless Network Simulation/Testing ... Figure 16: GPS Satellite 23 Figure 17: Milstar Satellite 25 ...

2006-06-01

186

Institute of Toxicology. 1994 annual report on research and development; Institut fuer Toxikologie. Ergebnisbericht ueber Forschung und Entwicklung 1994  

Energy Technology Data Exchange (ETDEWEB)

The R and D activities of the institute focused on two major projects, ``Molecular and cellular environmental toxicology``, and ``Biophysics of multi-cellular systems``. For assessment of health risks emanating from the uptake of heavy metal compounds, work performed under the first mentioned project studies the formation of allergy-inducing metabolic products from membrane lipids, and the effects of related cellular signaling processes. These studies are accompanied by an approach to quantify and classify the toxicity of environmental organometallic compounds. Another major task is research into the pathogenesis of lung disease induced by dusts, gases, and gas-dust mixtures and the liberation of inflammatory agents by immunological cell reactions (alveolar macrophages). Atomic force microscopy is the tool used to visualize the related dynamic changes in bronchial cells. Studies for detection of the localisation and structure of the Fe-Mo ...

1995-12-31

187

Validation of the GROMOS force-field parameter set 45A3 against nuclear magnetic resonance data of hen egg lysozyme  

Energy Technology Data Exchange (ETDEWEB)

The quality of molecular dynamics (MD) simulations of proteins depends critically on the biomolecular force field that is used. Such force fields are defined by force-field parameter sets, which are generally determined and improved through calibration of properties of small molecules against experimental or theoretical data. By application to large molecules such as proteins, a new force-field parameter set can be validated. We report two 3.5 ns molecular dynamics simulations of hen egg white lysozyme in water applying the widely used GROMOS force-field parameter set 43A1 and a new set 45A3. The two MD ensembles are evaluated against NMR spectroscopic data NOE atom-atom distance bounds, {sup 3}J{sub NH{alpha}} and {sup 3}J{sub {alpha}}{sub {beta}} coupling constants, and {sup 1}5N relaxation data. It is shown that the two sets reproduce structural properties about equally well. The 45A3 ensemble fulfills the atom-atom distance bounds derived ...

2004-12-15

188

ExternE - valuation of hydro power in Klippen. Final report; ExternE - vaerdering av vattenkraft i Klippen. Slutrapport  

Energy Technology Data Exchange (ETDEWEB)

ExternE is a pan{sub E}uropean project aimed at identifying and quantifying external effects from different energy production technologies around Europe. The Swedish implementation carried out case studies on a biomass plant, a coal plant and a hydro power plant. The conventional approach within the ExternE project is to estimate impacts for each priority pathway associated with the fuel cycle, and then economic methods to obtain estimates for the economic damage of each particular impact pathway. However, in the case of hydro power, it is generally not possible to estimate the most important impacts quantitatively. Therefore, a contingent valuation (CV) study was initiated. In a typical CV-study, a selection of individuals are asked to state their willingness to pay for a certain environmental improvement or to avoid an environmental damage. Welfare economic theory suggests that the well-being effects on people from a change from one situation to another can be ...

1998-08-01

189

Electro-volatilization of ruthenium in nitric medium: influences of ruthenium species nature and models solutions composition; Electro-volatilisation du ruthenium en milieu nitrique: influence de la nature des formes chimiques du ruthenium et de la composition des solutions modeles de dissolution  

Energy Technology Data Exchange (ETDEWEB)

Ruthenium is one of the fission products in the reprocessing of irradiated fuels that requires a specific processing management. Its elimination, upstream by the PUREX process, has been considered. A process, called electro-volatilization, which take advantage of the RuO{sub 4} volatility, has been optimised in the present study. It consists in a continuous electrolysis of ruthenium solutions in order to generate RuO{sub 4} species that is volatilized and easily trapped. This process goes to satisfying ruthenium elimination yields with RuNO(NO{sub 3}){sub 3}(H{sub 2}O){sub 2} synthetic solutions but not with fuel dissolution solutions. Consequently, this work consisted in the speciation studies of dissolved ruthenium species were carried out by simulating fuel solutions produced by hot acid attack of several ruthenium compounds (Ru(0), RuO{sub 2},xH{sub 2}O, polymetallic alloy). In parallel with dissolution kinetic studies, the determination of dissolved species was performed using ...

2004-12-15

190

Nepotistic cooperation in non-human primate groups  

UK PubMed Central (United Kingdom)

Darwin was struck by the many similarities between humans and other primates and believed that these similarities were the product of common ancestry. He would be even more impressed by the similarities...Full Text Available

2009-11-12

191

Spent Fuel Transportation Package Response to the Baltimore Tunnel Fire Scenario  

International Nuclear Information System (INIS)

On July 18, 2001, a freight train carrying hazardous (non-nuclear) materials derailed and caught fire while passing through the Howard Street railroad tunnel in downtown Baltimore, Maryland. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook an investigation of the train derailment and fire to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by railroad. Shortly after the accident occurred, the USNRC met with the National Transportation Safety Board (NTSB, the U.S. agency responsible for determining the cause of transportation accidents), to discuss the details of the accident and the ensuing fire. Following these discussions, the USNRC assembled a team of experts from the National Institute of Standards and Technology (NIST), the Center for Nuclear Waste Regulatory Analyses (CNWRA), and ...

2006-11-01

192

On the self-similarity of fractal colloidal aggregates in two dimensions  

Energy Technology Data Exchange (ETDEWEB)

It is argued that colloidal fractals are self-similar because all computed fractal dimensions of a given fractal have the same value. However, in a mathematical sense the self-similar character of a set implies not only that all fractal dimensions agree in value but also the existence of a set of similarities that generates the fractal. In this paper we report some results from two-dimensional aggregation experiments at the air-liquid interface and show that, with the appropriate selection for the similarities, the colloidal fractal aggregates can be considered as self-similar in a more mathematically rigorous form. (author)

2001-09-14

193

Gender similarities and differences in 200 individuals with body dysmorphic disorder?  

UK PubMed Central (United Kingdom)

BackgroundGender is a critically important moderator of psychopathology. However, gender similarities and differences in body dysmorphic disorder (BDD) have received...Full Text Available

2006-01-01

194

nasa_d_FEDMACSOILAIRTEMP.xml  

Science.gov (United States)

S.M. Goltz; NASA Goddard Space Flight Center, Forest Ecosystem Dynamics Project ...

198

Morphology, stellar kinematics and dynamics of barred galaxies  

International Nuclear Information System (INIS)

... Netherlands Kormendy, J. Dominion Astrophysical Observatory, Victoria, British

1982-08-09

209

Dynamic Study of Co-generator System Using EMTDC  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with dynamic study of co-generator system with derived dynamic models of generator, excitation system, and turbine/governor from field tests. Mainly this study concentrates on frequency control by under-frequency relay. We simulates dynamic study of co-generator system using EMTDC. (author). 4 refs., 13 figs., 4 tabs.

2001-07-01

212

Deforestation, floodplain dynamics, and carbon biogeochemistry in the Amazon Basin  

Science.gov (United States)

Three aspects of the physical geographic environment of the Amazon Basin are considered: (1)

1984-01-01

216

Moderate Deviations for a Curie-Weiss model with dynamical external field  

CERN Document Server

In the present paper we prove moderate deviations for a Curie-Weiss model with external magnetic field generated by a dynamical system, as introduced by Dombry and Guillotin-Plantard. The results extend those already obtained in the case of a constant external field by Eichelsbacher and L\\"owe. The Curie-Weiss model with dynamic external field is related to the so called dynamic Z-random walks. We also prove a moderate deviation result for the dynamic Z-random walk, completing the list of limit theorems for this object.

2011-01-01

217

Determination of Scaling Parameter and Dynamical Resonances in Complex-Rotated Hamiltonian II: Numerical Analysis  

International Nuclear Information System (INIS)

This paper is concerned with the determination of a unique scaling parameter in complex scaling analysis and with accurate calculation of dynamics resonances. In the preceding paper we have presented a theoretical analysis and provided a formalism for dynamical resonance calculations. In this paper we present accurate numerical results for two non-trivial dynamical processes, namely, models of diatomic molecular predissociation and of barrier potential scattering for resonances. The results presented in this paper confirm our theoretical analysis, remove a theoretical ambiguity on determination of the complex scaling parameter, and provide an improved understanding for dynamical resonance calculations in rigged Hilbert space.

2008-03-15

218

Vibrational population dynamics in liquids and glasses: IR pump-probe experiments from 10 K to 300 K  

Energy Technology Data Exchange (ETDEWEB)

The temperature dependent vibrational relaxation of the CO stretching mode of Rhodium dicarbonyl acetylacetonate (Rh(CO){sub 2}(acac)) and tungsten hexacarbonyl (W(CO){sub 6}) in dibutylphthalate (DBP) and 2-methylpentane (2-MP) were measured with IR pump and probe (P-P) experiments. The experiments were performed with {approximately}1.5 ps pulses generated by the Stanford superconducting accelerator pumped free electron laser (FEL). Measurements were performed on the Rh(CO){sub 2}(acac) CO asymmetric stretching mode at {lambda} = 4.98{mu}m from 10 K to 300 K. Both the parallel and magic angle probe polarizations decay curves are biexponential over the entire temperature range. The slow component (ranging from 40 ps at 300 K to 55 ps at 10K) is attributed to the population relaxations. For the fast component (ranging from 4-5 ps at 300 K to 13-15 ps at 10K), we propose a mechanism of spectral diffusion, in contrast to the previously proposed mechanisms of scattering between closely ...

1995-12-31

219

The all-electric drill ship  

Energy Technology Data Exchange (ETDEWEB)

Oil, in various forms, has been used for thousands of years and has even been recommended as a medicinal product. Starting in the mid-19. century, however, mineral oil production became an economic, political, social and scientific gold mine. Subterranean and offshore drilling rigs have created colossal fortunes among multinationals and made certain nations extremely wealthy. Starting in the 1920's, oil companies began to explore the possibilities of undersea drilling, but it was only in 1947 that the first offshore drilling rig was set up. With three-quarters of the planet covered by water, it was inevitable that oil companies would turn to offshore drilling - especially as sub-sea oil fields may cover as much as 84 million square kilometres. Drilling rigs now go deeper than ever and are able to operate in up to 3000 meters water depth. This paper will present the technical merits of two similar all-electric drill-ships 'Pride Africa' ...

2000-07-01

220

The ATG1/ATG13 Protein Kinase Complex Is Both a Regulator and a Target of Autophagic Recycling in Arabidopsis.  

Science.gov (United States)

Autophagy is an intracellular recycling route in eukaryotes whereby organelles and cytoplasm are sequestered in vesicles, which are subsequently delivered to the vacuole for breakdown. The process is induced by various nutrient-responsive signaling cascades converging on the Autophagy-Related1 (ATG1)/ATG13 kinase complex. Here, we describe the ATG1/13 complex in Arabidopsis thaliana and show that it is both a regulator and a target of autophagy. Plants missing ATG13 are hypersensitive to nutrient limitations and senesce prematurely similar to mutants lacking other components of the ATG system. Synthesis of the ATG12-ATG5 and ATG8-phosphatidylethanolamine adducts, which are essential for autophagy, still occurs in ATG13-deficient plants, but the biogenesis of ATG8-decorated autophagic bodies does not, indicating that the complex regulates downstream events required for autophagosome enclosure and/or vacuolar delivery. Surprisingly, levels of the ATG1a and ATG13a ...

2011-10-01

221

THE BURST MODE OF ACCRETION AND DISK FRAGMENTATION IN THE EARLY EMBEDDED STAGES OF STAR FORMATION  

International Nuclear Information System (INIS)

We revisit our original papers on the burst mode of accretion by incorporating a detailed energy balance equation into a thin-disk model for the formation and evolution of circumstellar disks around low-mass protostars. Our model includes the effect of radiative cooling, viscous and shock heating, and heating due to stellar and background irradiation. Following the collapse from the prestellar phase allows us to model the early embedded phase of disk formation and evolution. During this time, the disk is susceptible to fragmentation, depending upon the properties of the initial prestellar core. Globally, we find that higher initial core angular momentum and mass content favors more fragmentation, but higher levels of background radiation can moderate the tendency to fragment. A higher rate of mass infall onto the disk than that onto the star is a necessary but not a sufficient condition for disk fragmentation. More locally, both the Toomre Q-parameter needs to be below a critical value ...

2010-08-20

222

Studies of dynamic contact of ceramics and alloys for advanced heat engines: Final report  

Energy Technology Data Exchange (ETDEWEB)

In support of the efforts to apply ceramics in advanced heat engines, a study was made of the sliding performance of ceramics at the ring/cylinder interface of low heat rejection engines. The objective was to understand the basic mechanisms controlling the wear of candidate ceramics and thereby identify means for applying these ceramics effectively. Attempts to operate three different zirconias, silicon carbide, silicon nitride, and several plasma-sprayed ceramic coatings without lubrication were unsuccessful because of high friction and high wear rates. Experiments using a polyalphaolefin lubricant at temperatures to 260 C identified several combinations having wear rates in the general range likely to be acceptable for engines. Plasma-sprayed coatings of chromium oxide and hypersonic powder flame sprayed coatings of cobalt-bonded tungsten carbide performed particularly well as ring coatings. Similar performance was obtained with these ring coatings operating ...

1988-03-01

223

Spent fuel transportation cask response to a tunnel fire scenario  

Energy Technology Data Exchange (ETDEWEB)

On July 18, 2001, a freight train carrying hazardous (non-nuclear) materials derailed and caught fire while passing through the Howard Street railroad tunnel in downtown Baltimore, Maryland. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook an investigation of the train derailment and fire to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by railroad. Shortly after the accident occurred, the USNRC met with the National Transportation Safety Board (NTSB), the U.S. agency responsible for determining the cause of transportation accidents, to discuss the details of the accident and the ensuing fire. Following these discussions, the USNRC assembled a team of experts from the National Institute of Standards and Technology (NIST), the Center for Nuclear Waste Regulatory Analyses (CNWRA), and ...

2004-07-01

224

Plasma nitriding improvements of fatigue properties of nodular cast iron crankshafts  

Energy Technology Data Exchange (ETDEWEB)

Crankshafts of the pearlitic-sorbitic nodular cast iron type JUS NL.80 (similar to DIN GGG-80) heat treated to get a tensile strength of 820-900 GPa (i.e. a Vickers hardness of 268-295 HV) were plasma and ammonia gas nitrided. The glow discharge plasma nitriding was performed for 20 h at about 500degC in a gas mixture of 55% N{sub 2} and 45% H{sub 2}. The gas nitriding was performed for 28 h at 510degC in the ammonia gas. Evaluation of the nitrided surfaces was conducted by optical microscopy, X-ray diffractometry and microhardness measurements. Journal and crank pin dimensions and surface roughness were measured both before and after nitriding. Bending fatigue testing of crankshafts was performed using a fatigue testing rig. The fatigue limit was evaluated at 5.0x10{sup 6} cycles. The fractures happened at the transition radius of the journal with cracks starting beneath the nitrided layer. It was found that the nitrided crankshafts had 18% higher ...

1991-07-07

225

Mediation of bone ingrowth in porous hydroxyapatite bone graft substitutes.  

Science.gov (United States)

Previous investigations have shown that both the early biological response and the mechanical properties of a porous hydroxyapatite bone graft substitute are highly sensitive to its pore structure. The objective of this study was to evaluate whether the pore structure continued to influence bone integration in the medium to long term. Two screened batches of porous hydroxyapatite (PHA) designated as batch A and batch B, with porosities of approximately 60 and 80%, respectively, were selected for this study and implanted for periods of 5, 13, and 26 weeks into the lower femur of New Zealand White rabbits. Histomorphometric analysis of the absolute volume of bone ingrowth within batch A and B implants from 5 to 26 weeks showed that the absolute volume of bone ingrowth was consistently lower in batch A (10-21%), compared to batch B implants (24-31%). However, when the volume of bone ingrowth was normalised for the available pore space, this difference was reduced (23-47% and 32-42% for ...

2004-01-01

226

Magnetic Resonance Perfusion Imaging in Malformations of Cortical Development  

International Nuclear Information System (INIS)

Background: Malformations of cortical development vary in neuronal maturity and level of functioning. Purpose: To characterize regional relative cerebral blood volume (rCBV) and difference in first moment transit time (TTfm) in polymicrogyria and cortical tubers using magnetic resonance (MR) perfusion imaging. Material and Methods: MR imaging and dynamic T2*-weighted MR perfusion imaging were performed in 13 patients with tuberous sclerosis complex, 10 with polymicrogyria, and 18 controls with developmental delay but no macroscopic brain abnormality. Regions of interest were placed in cortical tubers or polymicrogyric cortex and in the contralateral normal-appearing side in patients with malformations. In 'control' subjects, regions of interest were placed in the frontal and parietal lobes in both hemispheres. The rCBV and TTfm of the tuber/contralateral side (rCBVRTSC and TTFMTSC) as well as those of the polymicrogyria/contralateral side (rCBVRPMG and TTFMPMG) ...

2007-10-01

227

Light charged particles and intermediate mass fragments from the reactions 486, 550, 640, and 730 MeV [sup 86]Kr + [sup 63]Cu  

Energy Technology Data Exchange (ETDEWEB)

A study has been made of the reaction [sup 86]Kr + [sup 63]Cu at incident energies of 486, 550, 640, and 730 MeV. Measurements include cross sections, angular distributions, and energy spectra for light charged particles ([sup 1,2,3]H and [sup 4]He), intermediate mass fragments (IMF) (4 [le] Z [le] 17), and heavy fragments (Z [ge] 18). Coincidences between light charged particles and between particles and fragments have been measured to obtain cross sections, energy spectra, and angular distributions. Statistical model analysis of the energy spectra for [sup 1]H and [sup 4]He detected in coincidence with the fragments has allowed estimation of [sup 1]H and [sup 4]He multiplicities associated with the evaporation residues, fragments, and composite nuclei prior to scission. A comparison of cross sections, energy spectra, angular distributions, and particle multiplicities for these matched entrance channels has provided the means for a detailed test of the Bohr Independence Hypothesis. ...

1992-01-01

228

Diffusion and adsorption of methane confined in nanoporous carbon aerogel: a combined quasi-elastic and small-angle neutron scattering study  

Energy Technology Data Exchange (ETDEWEB)

The diffusion of methane confined in nano-porous carbon aerogel with the average pore size 48 {angstrom} and porosity 60% was investigated as a function of pressure at T = 298 K using quasi-elastic neutron scattering (QENS). The diffusivity of methane shows a clear effect of confinement: it is about two orders of magnitude lower than in bulk at the same thermodynamic conditions and is close to the diffusivity of liquid methane at 100 K (i.e. {approx} 90 K below the liquid-gas critical temperature T{sub C} {approx} 191 K). The diffusion coefficient (D) of methane initially increases with pressure by a factor of {approx}2.5 from 3.47 {+-} 0.41 x 10{sup -10} m{sup 2} s{sup -1} at 0.482 MPa to D = 8.55 {+-} 0.33 x 10{sup -10} m{sup 2} s{sup -1} at 2.75 MPa and starts to decrease at higher pressures. An explanation of the observed non-monotonic behavior of the diffusivity in the confined fluid is based on the results of small-angle neutron scattering experiments of the phase behavior of ...

2010-04-01

229

Central engine of quasars and AGNs: a relativistic proton radiative shock  

International Nuclear Information System (INIS)

Active galactic nuclei (AGNs) and quasars (QSOs) appear to emit roughly equal energy per decade from radio to gamma-ray energies (e.g. Ramaty and Ligenfelter 1982). This argues strongly for a nonthermal radiation mechanism (see Rees 1984). In addition, statistical studies have indicated that the spectra of these objects in the IR-UV and 2 to 50 keV x-ray band, can be fitted very well with power laws of specific indices. These spectral indices do not seem to depend on the luminosity or morphology of the objects (Rothschild et al. 1983; Malkan 1984), and any theory should account for them in a basic and model independent way. If shocks accelerate relativistic protons via the first-order Fermi mechanism (e.g. Axfor 1981), the radiating electrons can be produced as secondaries throughout the source by proton-proton (p-p) collisions and pion decay, thus eliminating Compton losses (Protheroe and Kazanas 1983). As shown by Kazanas (1984), if relativistic electrons are injected at high ...

1985-08-01

230

Canon's flat-panel detector  

International Nuclear Information System (INIS)

We measured and evaluated digital, pre-sampling and overall imaging properties (characteristic curve, modulation transfer function (MTF), Wiener spectrum (WS), noise equivalent quanta (NEQ)) for Cannon's flat-panel detector (FPD), Fuji computed radiography (FCR) and screen-film (S/F) systems, respectively. First, the digital and overall characteristic curves of FPD and FCR systems were more wide dynamic range than that of the S/F system. Second, the pre-sampling and overall MTF of FPD system were better than those of FCR system a little at lower spatial frequencies than 0.8 mm"-"1, but the overall MTF of FPD and FCR systems were worse than that of S/F system a little at all spatial frequencies. Third, the digital and overall WS of FPD system were similar or better than those of FCR system, but the overall WS of FPD and FCR systems were worse than that of S/F system. Fourth, the pre-sampling and overall NEQ of FPD system were better than those ...

2002-12-01

231

Canon's flat-panel detector  

Energy Technology Data Exchange (ETDEWEB)

We measured and evaluated digital, pre-sampling and overall imaging properties (characteristic curve, modulation transfer function (MTF), Wiener spectrum (WS), noise equivalent quanta (NEQ)) for Cannon's flat-panel detector (FPD), Fuji computed radiography (FCR) and screen-film (S/F) systems, respectively. First, the digital and overall characteristic curves of FPD and FCR systems were more wide dynamic range than that of the S/F system. Second, the pre-sampling and overall MTF of FPD system were better than those of FCR system a little at lower spatial frequencies than 0.8 mm{sup -1}, but the overall MTF of FPD and FCR systems were worse than that of S/F system a little at all spatial frequencies. Third, the digital and overall WS of FPD system were similar or better than those of FCR system, but the overall WS of FPD and FCR systems were worse than that of S/F system. Fourth, the pre-sampling and overall NEQ of FPD system were better ...

2002-12-01

232

"Eztrack": A single-vehicle deterministic tracking algorithm  

Energy Technology Data Exchange (ETDEWEB)

A variety of surveillance operations require the ability to track vehicles over a long period of time using sequences of images taken from a camera mounted on an airborne or similar platform. In order to be able to see and track a vehicle for any length of time, either a persistent surveillance imager is needed that can image wide fields of view over a long time-span or a highly maneuverable smaller field-of-view imager is needed that can follow the vehicle of interest. The algorithm described here was designed for the persistence surveillance case. In turns out that most vehicle tracking algorithms described in the literature[1,2,3,4] are designed for higher frame rates (> 5 FPS) and relatively short ground sampling distances (GSD) and resolutions ({approx} few cm to a couple tens of cm). But for our datasets, we are restricted to lower resolutions and GSD's ({ge}0.5 m) and limited frame-rates ({le}2.0 Hz). As a consequence, we designed our own ...

2007-12-20

233

Subclinical interstitial lung involvement in rheumatic diseases. Correlations of high-resolution Computed Tomography patterns with functional and cytologic findings  

International Nuclear Information System (INIS)

The aims of this study were to quantify the severity and extent of subclinical interstitial lung disease as depicted on HRCT and to study the relationship between the patterns of lung disease quantified by HRCT and the functional parameters and bronchoalveolar lavage findings in patients with rheumatic diseases. The results confirm that HRCT is a sensitive tool in detecting interstitial lung disease in patients with rheumatic diseases with no signs and symptoms of pulmonary involvement. The relationship between the different HRCT patterns and bronchoalveolar lavage cell profiles can identify patients at higher risk of developing irreversible lung fibrosis. A long-term, prospective follow-up study is needed to determine whether these patients will develop over pulmonary disease.

1999-01-01

234

Quantifying the thermal flowering rates of eighteen species of annual bedding plants  

British Library Electronic Table of Contents (United Kingdom)

The effect of mean daily air temperature (MDT) on flowering rate (the reciprocal of days to flower) was quantified for 18 species of annual bedding plants. Plants were grown in environmental growth chambers at constant air temperature set points of 5, 7.5, 10, 15, 25, or 30^oC and under an irradiance of 160-180mmolm^-^2s^-^1, with a 16-h photoperiod. Nonlinear mathematical equations were developed to predict the effect of MDT on flowering rate and to estimate the base, optimum, and maximum temperatures (Tmin, Topt, and Tmax), which are the temperatures at which flowering rates are zero (low temperature), maximal, and zero once again (high temperature), respectively. The estimated Tmin varied among species and ranged from 1.1^oC in French marigold (Tagetes patula L.) to 9.9^oC in angelonia ...

2011-01-01

235

Methods for proving the equivalency of detonator performance  

Energy Technology Data Exchange (ETDEWEB)

One of the challenges facing engineers is developing newer, safer detonators that are equivalent to devices currently in use. There is no clear consensus on an exact method for drawing equivalence of detonators. This paper summarizes our current efforts to develop diagnostics addressing various aspects of detonator design to better quantify and prove equivalency. We consider various optical techniques to quantify the output pressure and output wave shape. The development of a unique interpretation of streak camera breakouts, known as the apparent center of initiation, will be discussed as a metric for detonation wave shape. Specific examples apply these techniques to the comparison of a new laser-driven detonator with an existing exploding bridgewire (EBW) detonator. Successes and short-comings of the techniques will be discussed.

2009-01-01

236

Mapping burned areas and burn severity patterns in SW Australian eucalypt forest using remotely-sensed changes in leaf area index  

British Library Electronic Table of Contents (United Kingdom)

Remote sensing is the most practical method available to managers of fire-prone forests for quantifying and mapping fire impacts. Differenced Normalised Burn Ratio (?NBR) is among the most widely used spectral indices for the mapping of burn severity but is difficult to interpret in terms of fire-related changes in key biophysical attributes and processes. We propose to quantify burn severity as a change in the leaf area index (?LAI) of a stand. LAI is a key biophysical attribute of forests, and is central to understanding their water and carbon cycles. Previous studies have suggested that changes in canopy LAI may be a major contributor to ?NBR and to the composite burn index (CBI) that is frequently used in combination with the NBR to assess burn severity on the ground. We applied remote...

2008-01-01

237

Language morphology offset: Text classification on a Croatian-English parallel corpus  

British Library Electronic Table of Contents (United Kingdom)

We investigate how, and to what extent, morphological complexity of the language influences text classification using support vector machines (SVM). The Croatian-English parallel corpus provides the basis for direct comparison of two languages of radically different morphological complexity. We quantified, compared, and statistically tested the effects of morphological normalisation on SVM classifier performance based on a series of parallel experiments on both languages, carried over a large scale of different feature subset sizes obtained by different feature selection methods, and applying different levels of morphological normalisation. We also quantified the trade-off between feature space size and performance for different levels of morphological normalisation, and compared the resul...

2008-01-01

238

Example of second-law efficiency of solar-thermal cavity receivers  

Energy Technology Data Exchange (ETDEWEB)

Properly quantified performance of a solar-thermal cavity receiver must not only account for the energy gains and losses as dictated by the First Law of thermodynamics, but it must also account for the quality of that energy. Energy quality can only be determined from the Second Law. In this paper, an equation developed for the Second-Law efficiency of a cavity receiver is presented as an evolution from the definition of available energy or ''availability'' (occasionally called exergy). The variables required are all either known or readily determined. The importance of considering the Second-Law is emphasized by a comparison of the First- and Second-Law efficiencies around an example of data collected from two receivers that were designed for different purposes, where the attempt was made to demonstrate that a Second-Law approach to quantifying the performance of a solarthermal cavity receiver lends more ...

1986-02-01

239

Environmental costs and benefits case study: nuclear power plant. Quantification and economic valuation of selected environmental impacts/effects. Final report  

International Nuclear Information System (INIS)

This case study is an application, to a nuclear power plant, of the methodology for quantifying environmental costs and benefits, contained in the regional energy plan, adopted in April, 1983, by the Northwest Power Planning Council, pursuant to Public Law 96-501.The study is based on plant number 2 of the Washington Public Power Supply System (WNP-2), currently nearing completion on the Hanford Nuclear Reservation in eastern Washington State. This report describes and documents efforts to quantify and estimate monetary values for the following seven areas of environmental effects: radiation/health effects, socioeconomic/infrastructure effects, consumptive use of water, psychological/health effects (fear/stress), waste management, nuclear power plant accidents, and decommissioning costs. 103 references.

240

Dialysis membrane for separation on microchips  

Energy Technology Data Exchange (ETDEWEB)

Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

2010-07-13

241

Blood flow quantification with MRI using the phase mapping method. Moeglichkeiten und Grenzen der Blutflussquantifizierung peripherer arterieller Gefaesse mit der MRT unter Anwendung des Phase-Mapping-Verfahrens  

Energy Technology Data Exchange (ETDEWEB)

MRT is able to demonstrate arteries while MR angiography can quantify blood flow by a non-invasive method. In the present paper blood flow measurements were carried out in four selected cases on the basis of phase mapping. In 3 patients with lesions in the pelvis or thigh, angiography was performed in order to localise the stenosis or occlusion and this was followed by qantitative blood flow measurements. The results showed that angiography may not always provide all necessary information concerning a haemodynamically significant stenosis. The method may also be used for quantifying blood flow in the renal arteries and that it has significant advantages over the colour Doppler method. (orig.).

1992-08-01

242

A novel method for quantifying scanner instability in fMRI  

British Library Electronic Table of Contents (United Kingdom)

Abstract A method was developed to quantify the effect of scanner instability on functional MRI data by comparing the instability noise to endogenous noise present when scanning a human. The instability noise was computed from agar phantom data collected with two flip angles, allowing for a separation of the instability from the background noise. This method was used on human data collected at four 3 T scanners, allowing the physiological noise level to be extracted from the data. In a -well-operating- scanner, the instability noise is generally less than 10% of physiological noise in white matter and only about 2% of physiological noise in cortex. This indicates that instability in a well-operating scanner adds very little noise to functional MRI results. This new method allows researcher...

2011-01-01

243

A new method for quantifiable and controlled dosage of particulate matter for in vitro studies: The electrostatic particulate dosage and exposure system (EPDExS)  

British Library Electronic Table of Contents (United Kingdom)

An exposure chamber is described for the quantifiable addition of fine and ultrafine aerosol particulate matter directly to cells and used to demonstrate the in vitro cytotoxicity of fine 1,4-naphthoquinone particles to murine lung epithelial cells. The electrostatic particulate dosage and exposure system (EPDExS) operates on the principle of electrostatic precipitation and is shown to deposit fine and ultrafine aerosol particles directly to cells with 100% efficiency for particle diameters in the range of 40-530nm. This range is not limited by the EPDExS, but rather by the aerosolization method used for this study. Numbers of particles deposited onto the cells are counted with a condensation particle counter, negating any need to calculate or estimate particle exposure. The process of par...

2008-01-01

244

Fibrous Carbon  

Science.gov (United States)

... was noted. It was reported that similar fibers also grew on particles of thermal carbon black at a temperature of 10500 and in an atmosphere ...

1963-05-10

245

Power system stabilizer based on inverse dynamics using an artificial neural network  

Energy Technology Data Exchange (ETDEWEB)

A stable power system stabilizer (PSS) based on the inverse dynamics of the controlled system using an artificial neural network (ANN) is suggested to enhance the dynamic performances of a power system. First, an output feedback control law is driven with some conditions satisfied, which guarantees the internal stability and robustness against the asymptotically stable external disturbances. Then the control law is implemented using the inverse dynamics of the controlled plant. The inverse dynamics of the controlled plant is identified by an ANN, inverse dynamics neural network (IDNN), off-line. The pole-shifting technique and a scaling factor are introduced for the control system to meet the conditions for internal stability and robustness. The proposed controller is applied to a typical single-machine infinite-bus power system. Simulation results under various operation conditions ...

1996-06-01

246

Summary of Omega West Reactor, Level 1, probabilistic risk assessment  

International Nuclear Information System (INIS)

This paper reports on a Level 1 PRA performed on the Omega West Reactor at Los Alamos National Laboratory. A Master Logic Diagram was used to identify possible initiating events. A chi-square distribution was used to quantify initiating event frequencies given that no initiating events have occurred in 30 years of OWR operation. The PRA results are presented as both probability density function and cumulative distribution function curves.

1990-10-04

247

Secondary co-refining of petroleum and coal distillates, and the evaluation of coal cleaning in coal liquefaction  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a research and development project to quantify the effects of cleaning the coal feed on the yield patterns and processing rates for the Liquid Solvent Extraction (LSE) direct coal liquefaction process and to obtain information on the effect of the co-refining of coal-derived and petroleum distillates to premium transport fuels. 6 refs., 25 figs., 40 tabs.

1992-12-31

248

Quantifying octahedral rotations in strained perovskite oxide films.  

Energy Technology Data Exchange (ETDEWEB)

We have measured the oxygen positions in LaNiO{sub 3} films to elucidate the coupling between epitaxial strain and oxygen octahedral rotations. The oxygen positions are determined by comparing the measured and calculated intensities of half-order Bragg peaks, arising from the octahedral rotations. Combining ab initio density-functional calculations with these experimental results, we show how strain systematically modifies both bond angles and lengths in this functional perovskite oxide.

2010-07-20

249

Petroleum waxes in solvent systems  

Energy Technology Data Exchange (ETDEWEB)

Wax appearance temperature (WAT) of three petroleum waxes in different solvent systems under varying thermal conditions has been determined. It is observed that this temperature mainly is a function of the concentration of the wax and the solubility parameter ([delta]) of the solvent taken. This dependence of WAT has been quantified in terms of these variables in the form of mathematical equation and nomographs. (orig.)

1994-01-01

250

PIXE analysis of trace elements in relation to chlorophyll concentration in Plantago ovata Forsk  

Energy Technology Data Exchange (ETDEWEB)

Plantago ovata Forsk - an economically important medicinal plant - was analyzed for trace elements and chlorophyll in a study of the effects of gamma radiation on physiological responses of the seedlings. Proton-induced X-ray emission (PIXE) technique was used to quantify trace elements in unirradiated and gamma-irradiated plants at the seedling stage. The experiments revealed radiation-induced changes in the trace element and chlorophyll concentrations.

2010-03-15

251

Measurement and apportionment of radon source terms for modeling indoor environments  

Energy Technology Data Exchange (ETDEWEB)

This research has two main goals; (1) to quantify mechanisms for radon entry into homes of different types and to determine the fraction of indoor radon attributable to each source and (2) to model and calculate the dose (and therefore alpha particle fluence) to cells in the human and animal tracheobronchial tree that is pertinent to induction of bronchogenic carcinoma from inhaled radon daughters.

1990-01-01

252

Levels and distribution of BCNU in GBM tumors following intratumoral injection of DTI-015 (BCNU-ethanol)  

UK PubMed Central (United Kingdom)

The alkylation products formed by in vitro treatment of DNA with tritium-labeled 1,3-bis(2-chloroethyl)-1-nitrosourea (3H-BCNU) were identified and quantified. Twelve adducts were resolved...Full Text Available

2007-01-01

253

Experts' discussion on the possibility of quantification of the radiation hazard  

International Nuclear Information System (INIS)

Due to the intensity and vast number of subjects, this Bremen experts' discussion, too, could discuss only part of the problem of the possibilitiy to quantify the radiation hazard. One preliminary result is that there is no scientific proof of the harmlessness of radiation exposure during normal operation of a nuclear power plant, either within the plant or in its vicinity. Other results are that some important questions can not be answered yet, and that there are important hints on the dangers even of low radiation doses. (GL).

1978-01-01

254

Effects of 2 commercially-available 9-way killed vaccines on milk production and rectal temperature in Holstein-Friesian dairy cows.  

UK PubMed Central (United Kingdom)

Veterinarians and farmers employing multivalent killed vaccines in lactating dairy cows have reported transient losses in milk production. Few studies have quantified this loss. In this report, effects...Full Text Available

2001-10-01

255

Effectiveness of information provision in reducing risks to the environment  

Environmental Research Database

DescriptionAs part of a wider effort to develop new approaches to evaluating and quantifying the benefits of chemicals regulation, this project will review the effectiveness of existing information provision tools (such as classification and labelling for hazardous properties) in terms of affecting user behaviour. As some EC legislation relating to regulation of chemicals has been in place for some time, an assumption is made that the information provided by it is leading to an improvement in the way chem [continued...

2005-01-30

256

Complex fractal dimensions describe the hierarchical structure of diffusion-limited-aggregate clusters  

Energy Technology Data Exchange (ETDEWEB)

We analyze large diffusion-limited aggregates and uncover a {ital discrete} scaling invariance in their inner structure, which can be quantified by the introduction of a set of {ital complex} fractal dimensions. We provide a theoretical framework and prediction of their values based on renormalization group theory and a previous wavelet analysis. {copyright} {ital 1996 The American Physical Society.}

1996-01-01

257

Clinical helical tomotherapy commissioning dosimetry  

International Nuclear Information System (INIS)

Helical tomotherapy presented many unique dosimetric challenges and solutions during the initial commissioning process, and some of them are presented. The dose calculation algorithm is convolution/superposition based. This requires that the energy fluence spectrum and magnitude be quantified. The methodology for doing so is described. Aspects of the energy fluence characterization that are unique to tomotherapy are highlighted. Many beam characteristics can be measured automatically by an included megavoltage computed tomography imaging system. This greatly improves data collection efficiency.

2003-12-01

258

Two-phase flow regime modeling  

International Nuclear Information System (INIS)

This paper describes a long term course of research into the fundamentals of two phase flow regime dynamics that had lead to a differential description of regime properties. The development has included experiment, microscale simulation, and mathematical averaging to produce a dynamic equation for interfacial area.

1981-03-01

259

The Dynamical Mechanism of Auto-Inhibition of AMP-Activated Protein Kinase  

UK PubMed Central (United Kingdom)

We use a novel normal mode analysis of an elastic network model drawn from configurations generated during microsecond all-atom molecular dynamics simulations to analyze the mechanism of auto-inhibition...Full Text Available

2011-07-01

260

Stretched DNA Investigated Using Molecular-Dynamics and Quantum-Mechanical Calculations  

UK PubMed Central (United Kingdom)

AbstractWe combined atomistic molecular-dynamics simulations with quantum-mechanical calculations to investigate the sequence dependence of the stretching behavior of duplex DNA. Our...Full Text Available

2010-01-06

261

Ring opening reaction dynamics of a photochromic diarylethene derivative dye  

International Nuclear Information System (INIS)

Ring opening dynamics of diarylethene derivative (BTF6) in n-hexane are studied by femtosecond transient absorption and time resolved spontaneous fluorescence techniques. Cyclo-reversion time constant is obtained.

2001-11-01

262

Rhythmic Dynamics and Synchronization via Dimensionality Reduction: Application to Human Gait  

UK PubMed Central (United Kingdom)

Reliable characterization of locomotor dynamics of human walking is vital to understanding the neuromuscular control of human locomotion and disease diagnosis. However, the inherent oscillation and...Full Text Available

2010-12-01

263

Molecular dynamics of a ?B DNA element: base flipping via cross-strand intercalative stacking in a microsecond-scale simulation  

UK PubMed Central (United Kingdom)

The sequence-dependent structural variability and conformational dynamics of DNA play pivotal roles in many biological milieus, such as in the site-specific binding of transcription factors to target...Full Text Available

2008-09-01

264

Molecular Dynamics Simulations of the Detoxification of Paraoxon Catalyzed by Phosphotriesterase (PTE)  

UK PubMed Central (United Kingdom)

Combined QM(PM3)/MM molecular dynamics simulations together with QM(DFT)/MM optimizations for key configurations have been performed to elucidate the enzymatic catalysis mechanism on the detoxification...Full Text Available

2009-11-30

265

Modular coherence of protein dynamics in yeast cell polarity system  

UK PubMed Central (United Kingdom)

In this study, we investigated on a systems level how complex protein interactions underlying cell polarity in yeast determine the dynamic association of proteins with the polar cortical domain (PCD)...Full Text Available

2011-05-03

266

Misclassification of Patients with Spinocerebellar Ataxia as Having Psychogenic Postural Instability Based on Computerized Dynamic Posturography  

UK PubMed Central (United Kingdom)

Specific criteria have been developed based on computerized dynamic posturography (CDP) to assist clinicians in identifying patients with psychogenic balance problems (Cyr and Cevette, Full Text Available

267

Minimum Two-Year Follow-Up of Cases with Recurrent Disc Herniation Treated with Microdiscectomy and Posterior Dynamic Transpedicular Stabilisation  

UK PubMed Central (United Kingdom)

The objective of this article is to evaluate two-year clinical and radiological follow-up results for patients who were treated with microdiscectomy and posterior dynamic transpedicular stabilisation...Full Text Available

268

Mathematical model of a utility firm. Final technical report, Part IIB  

Energy Technology Data Exchange (ETDEWEB)

The aim of this project was to develop an understanding of the dynamical processes that evolve within an electric utility firm, and without it. This volume covers organizational dynamics and control, and planning under uncertainty. (DLC)

1983-08-21

269

Magnetic resonance imaging and computational fluid dynamics (CFD) simulations of rabbit nasal airflows for the development of hybrid CFD/PBPK models  

UK PubMed Central (United Kingdom)

The percentages of total airflows over the nasal respiratory and olfactory epithelium of female rabbits were calculated from computational fluid dynamics (CFD) simulations of steady-state inhalation....Full Text Available

2009-05-01

270

Infection dynamics and clinical manifestations following experimental inoculation of gilts at 90 days of gestation with a low dose of porcine reproductive and respiratory syndrome virus  

UK PubMed Central (United Kingdom)

Understanding the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) vertical transmission is important to enhance the accuracy of monitoring protocols for endemically infected...Full Text Available

2009-10-01

271

Hydrodynamics in an external field  

CERN Document Server

The methods of statistical dynamics are applied to a fluid with 5 conserved fields (the mass, the energy, and the three components of momentum) moving in a given external potential. When the potential is zero, we recover a previously derived system of parabolic differential equations, called "corrections to fluid dynamics".

2002-01-01

272

Homeostasis of intrinsic excitability in hippocampal neurones: dynamics and mechanism of the response to chronic depolarization  

UK PubMed Central (United Kingdom)

In order to maintain stable functionality in the face of continually changing input, neurones in the CNS must dynamically modulate their electrical characteristics. It has been hypothesized that in...Full Text Available

2010-01-01

273

Dynamics of Microbial Communities on Marine Snow Aggregates: Colonization, Growth, Detachment, and Grazing Mortality of Attached Bacteria  

UK PubMed Central (United Kingdom)

We studied the dynamics of microbial communities attached to model aggregates (4-mm-diameter agar spheres) and the component processes of colonization, detachment, growth, and grazing mortality. Agar...Full Text Available

2003-06-01

274

Dynamic and Static Tests of Plain Concrete Specimens ...  

Science.gov (United States)

... 4.4+9 4.30 ds~ ;'* Page 24. Table 3 Ultimate Compressive Strength Data Static Dynamic Round Strength Range Strength Range No. Avg Rise 0No. ...

1963-11-01

275

Dynamic NMR effects in breast cancer dynamic-contrast-enhanced MRI  

UK PubMed Central (United Kingdom)

The passage of a vascular-injected paramagnetic contrast reagent (CR) bolus through a region-of-interest affects tissue 1H2O relaxation and thus MR image intensity. For longitudinal...Full Text Available

2008-11-18

276

Dynamic Conditionally Linear Mixed Models for Longitudinal Data  

UK PubMed Central (United Kingdom)

SummaryWe develop a new class of models, dynamic conditionally linear mixed models, for longitudinal data by decomposing the within-subject covariance matrix using a special Cholesky...Full Text Available

2002-03-01

277

Do Woody Plants Operate Near the Point of Catastrophic Xylem Dysfunction Caused by Dynamic Water Stress? 1  

UK PubMed Central (United Kingdom)

We discuss the relationship between the dynamically changing tension gradients required to move water rapidly through the xylem conduits of plants and the proportion of conduits lost through embolism...Full Text Available

1988-11-01

278

Cement-based composites: Strain rate effects on fracture  

Energy Technology Data Exchange (ETDEWEB)

This book contains over 20 selections. Some of the titles are: Continuum damage mechanics studies on the dynamic fracture of concrete; Dynamic compressive strength of cementitious materials; Rate-sensitivity of mode I and mode II fracture concrete; and An impact damage model of concrete.

1986-01-01

279

An Aggregate Dynamic Stochastic Model for an Air Traffic System  

Science.gov (United States)

processes, we construct a stochastic dynamic model for air- craft counts in ... Also , queueing models for the arrival of aircraft at ... A queueing model has also been used to study ...... Assignment and Aircraft-Sequencing Algorithms in Terminal ...

280

Algebraic Structure of Linear Dynamical Systems. III. Realization Theory Over a Commutative Ring  

UK PubMed Central (United Kingdom)

The realization theory linear dynamical systems, previously developed over a field, are extended to a large class of commutative rings. The principal result is that the existence criterion for a finite...Full Text Available

1972-11-01

281

Adhesive capsulitis and dynamic splinting: a controlled, cohort study  

UK PubMed Central (United Kingdom)

BackgroundAdhesive Capsulitis (AC) affects patient of all ages, and stretching protocols are commonly prescribed for this condition. Dynamic splinting has been shown effective in...Full Text Available

282

The radioecological risk of decommissioning of nuclear submarines. Possible accidents and normal conditions  

International Nuclear Information System (INIS)

In the report the results of the estimations of radiological risk of various stages of decommissioning of nuclear submarines are presented. At occurrence on nuclear submarine the heavy failure, relating to the class hypotetical volume of acting of radionuclides in atmosphere can reach 1.6E(15) Bq. Results of estimations probable doses on an axis of a trace of a radioactive loop show, that at distribution of radionuclides during atmospheric carry to 'agreed' settlement (500-1000 m) the maximum doses on its territory can make: about 6.0E(-3) Sv (for the whole body); 3.0E(-3) Gy for the leather (basal layer); 6.3E(-2) Gy for the lungs (acute exposure) and up to 1.8 Gy for the thyroid gland. Hypotetical failure for the estimation of the greatest possible radioecological consequences for hydrobiocenosis is considering, connected with single discharge of liquid radioactive waste (LRW) in water area. At navigating failure of the tanker with LRW in water area can arrive 300 M3 of LRW with the ...

2000-05-01

283

Wideband Modulation and Tuning of Semiconductor Lasers ...  

Science.gov (United States)

... Tunable semiconductor lasers are essential components for links employing optical frequency modulation (OFM) for enhanced dynamic range or ...

1996-07-01

284

Theorizing Land Cover and Land Use Changes: The Case of Tropical Deforestation  

Science.gov (United States)

This article addresses land-cover and land-use dynamics from the perspective of regional science and

2004-01-01

285

The Value of Information The Metaphysics of Information The - NASA  

Science.gov (United States)

Wikileaks was inevitable. The Dynamics of. Information. Take advantage of the eddy currents. You can't step in the same river ...

286

The Macro Model of the Inequality Process and The Surging Relative Frequency of Large Wage Incomes  

CERN Document Server

This paper presents a model of the dynamics of the wage income distribution.

2007-01-01

287

Special Course on Three-Dimensional Supersonic ...  

Science.gov (United States)

... Dynamics Panel Executive AGARD 7 rue ... 4 AXIAL FLOW IN CORNERS AT SUPERSONIC ... AND HYPERSONIC FLOWS INCLUDING SEPARATION ...

1990-01-01

288

Scenario-Based Affordability Assessment Tool  

Science.gov (United States)

... Dynamics) environment (ref. 13) to work seamlessly with their flagship products, MSC.Nastran and MSC.Patran. In addition ...

2003-03-01

289

Robust computationally efficient control of cooperative closed-chain manipulators with uncertain dynamics  

British Library Electronic Table of Contents (United Kingdom)

This article presents a decentralized control scheme for the complex problem of simultaneous position and internal force control in cooperative multiple manipulator systems. The proposed controller is composed of a sliding mode control term and a force robustifying term to simultaneously control the payloads position/orientation as well as the internal forces induced in the system. This is accomplished independently of the manipulators dynamics. Unlike most controllers that do not require prior knowledge of the manipulators dynamics, the suggested controller does not use fuzzy logic inferencing and is computationally inexpensive. Using a Lyapunov stability approach, the controller is proven to be robust in the face of varying systems dynamics. The payloads position/orientation and the inte...

2007-01-01

290

Resonance spin-echo option on neutron reflectometers for the study of dynamics of surfaces and interfaces  

Energy Technology Data Exchange (ETDEWEB)

The applications of neutron reflectometry to study dynamic phenomena at surface and interfaces have been restricted so far. This was mainly due to the low intensity of neutron sources, but now high-intensity spallation neutron sources are under construction in Japan (J-PARC) and US (SNS). We are planning to install a spin-echo option on the J-PARC neutron reflectometer with horizontal sample geometry for studies of dynamics of surfaces and interfaces. This option is based on the resonance spin-echo method and aimed at dynamics up to hundreds of nanoseconds. In this contribution, the plan and status of development are introduced together with the principle and characteristics of this option.

2005-02-15

291

Recrystallization during and following hot working of magnesium alloy AZ31  

Energy Technology Data Exchange (ETDEWEB)

The microstructures of magnesium AZ31 are examined following hot compression testing and annealing. The grain size, fraction dynamically recrystallized and, in a couple of cases, the crystallographic texture are reported. It was found that the progress of dynamic recrystallization is strongly sensitive to processing conditions but that the dynamically recrystallized grain size was less sensitive to stress than in other metals. It was also found that, for structures containing between 80 and 95% dynamic recrystallization, abnormal grain growth occurs during annealing. The crystallographic texture produced is also sensitive to the deformation conditions. (orig.)

2003-07-01

292

NASTRAN nonlinear dynamic transient accident analysis for FFTF reactor component  

International Nuclear Information System (INIS)

... computer calculations fftf reactor nonlinear problems reactor accidents reactor

1976-11-14

294

Healthy Nutrition: Breastfeeding  

Medline Plus

... Dynamics Media Work & Play Health Issues Conditions Abdominal ADHD Allergies & Asthma Chest & Lungs Chronic Conditions Developmental Disabilities ...

296

Flow Control  

Science.gov (United States)

... 65th AGARD Fluid Dynamics Symposium, Madrid, Spain, October ... of research programs on flow control ... separation, and delta wing flows formed the ...

1991-04-30

299

Development and Calibration of Two and Four Wire Water ...  

Science.gov (United States)

... measurement. Power spectral density measurements are made by the dynamic signal analyzer for each channel. A cross power ...

1992-12-01

300

Chiral dynamics of few-nucleon systems  

Energy Technology Data Exchange (ETDEWEB)

I discuss some recent developments in chiral effective field theory for few-nucleon systems.

2008-06-01

301

Adaptive System and Method for Responding to Computer ...  

Science.gov (United States)

Page 1. Adaptive system and method for responding to computer network security attacks Abstract A dynamic network security ...

2002-07-11

302

Intuitionistic and interval-valued intutionistic fuzzy preference relations and their measures of similarity for the evaluation of agreement within a group  

British Library Electronic Table of Contents (United Kingdom)

Szmidt and Kacprzyk (Lecture Notes in Artificial Intelligence 3070:388?393, 2004a) introduced a similarity measure, which takes into account not only a pure distance between intuitionistic fuzzy sets but also examines if the compared values are more similar or more dissimilar to each other. By analyzing this similarity measure, we find it somewhat inconvenient in some cases, and thus we develop a new similarity measure between intuitionistic fuzzy sets. Then we apply the developed similarity measure for consensus analysis in group decision making based on intuitionistic fuzzy preference relations, and finally further extend it to the interval-valued intuitionistic fuzzy set theory.

2009-01-01

303

Monitoring interfacial dynamics by pulsed laser techniques. [Annual report  

Energy Technology Data Exchange (ETDEWEB)

Goal was developing optical methods for study of dynamic processes at the electrode/electrolyte interface. In the past year, optical second harmonic generation was used for time-resolved measurements of thallium deposition on Cu(111). The studies of carrier dynamics in photo-excited materials have involved both steady-state and picosecond time-resolved luminescence measurements following photoexcitation of the semiconductor material.

1992-12-31

304

Dynamics of Axial Separation in Long Rotating Drums  

Energy Technology Data Exchange (ETDEWEB)

We propose a continuum description for the axial separation of granular materials in a long rotating drum. The model, operating with two local variables, concentration difference and the dynamic angle of repose, describes both initial transient traveling wave dynamics and long-term segregation of the binary mixture. Segregation proceeds through ultraslow logarithmic coarsening. {copyright} {ital 1999} {ital The American Physical Society}

1999-06-01

305

Dynamics and controls working group summary  

Energy Technology Data Exchange (ETDEWEB)

The technology status of the dynamics and controls discipline as it applies to energy storage wheel systems was evaluated. No problems were identified for which an adequate solution could not be proposed. Design issues that influence control were addressed. The dynamics and control aspects associated with the energy storage system concept and its various constituent parts, and the control tasks attendant to large, manned spacecraft are discussed.

1984-11-01

306

Dynamical evolution and molecular abundances of interstellar clouds  

International Nuclear Information System (INIS)

Dynamical models are presented that start with interstellar gas in an initial diffuse state and consider their gravitational collapse and the formation of dense cores. Frozen-in tangled magnetic fields are included to mimic forces that might oppose gravitational contraction and whose effectiveness may increase with increasing core densities. Results suggest the possibility that dense cloud cores may be dynamically evolving ephemeral objects, such that their lifespan at a given core density decreases as that density increases. 66 refs.

307

Dynamic positive column in long-gap barrier discharges  

CERN Document Server

A simple analytical model of the barrier discharge in a long gap between opposing plane electrodes is developed. It is shown that the plasma density becomes uniform over large part of the gap in the course of the discharge development, so that one can speak of a formation of a dynamic positive column. The column completely controls the dynamics of the barrier discharge and determines such characteristics as the discharge current, discharge duration, light output, etc. Using the proposed model, all discharge parameters can be easily evaluated

2005-01-01

308

Dynamic behavior of a solar-heated receiver of a gas turbine plant  

Energy Technology Data Exchange (ETDEWEB)

The mainly nonstationary operation of a solar-heated receiver can be simulated with sufficient accuracy only if data about the dynamic behavior are available. For this reason, the dynamic behavior of a solar cavity receiver with parabolic dish collector is investigated. The development of a mathematical simulation considering heat transfer and storage processes is presented and the procedure for a numerical solution is illustrated. The performance of the calculation method is finally demonstrated by simulating the passage of a cloud.

1987-01-01

309

Dynamic behavior of a solar heated receiver of a gas turbine plant  

Energy Technology Data Exchange (ETDEWEB)

The mainly instationary operation of a solar heated receiver can be simulated with sufficient accuracy only if data about the dynamic behavior are available. For this reason, the dynamic behavior of a solar cavity receiver with parabolic dish collector is investigated. The development of a mathematical simulation considering heat transfer and storage processes is presented and the procedure for a numerical solution is illustrated. The performance of the calculation method is finally demonstrated by simulating the passage of a cloud.

1986-01-01

310

Controllable Subspaces of Open Quantum Dynamical Systems  

International Nuclear Information System (INIS)

This paper discusses the concept of controllable subspace for open quantum dynamical systems. It is constructively demonstrated that combining structural features of decoherence-free subspaces with the ability to perform open-loop coherent control on open quantum systems will allow decoherence-free subspaces to be controllable. This is in contrast to the observation that open quantum dynamical systems are not open-loop controllable. To a certain extent, this paper gives an alternative control theoretical interpretation on why decoherence-free subspaces can be useful for quantum computation.

2008-01-15

311

Feasibility study for use of the natural convection shutdown heat removal test facility (NSTF) for VHTR water-cooled RCCS shutdown  

International Nuclear Information System (INIS)

In summary, a scaling analysis of a water-cooled Reactor Cavity Cooling System (RCCS) system was performed based on generic information on the RCCS design of PBMR. The analysis demonstrates that the water-cooled RCCS can be simulated at the ANL NSTF facility at a prototypic scale in the lateral direction and about half scale in the vertical direction. Because, by necessity, the scaling is based on a number of approximations, and because no analytical information is available on the performance of a reference water-cooled RCCS, the scaling analysis presented here needs to be 'validated' by analysis of the steady state and transient performance of a reference water-cooled RCCS design. The analysis of the RCCS performance by CFD and system codes presents a number of challenges including: strong 3-D effects in the cavity and the RCCS tubes; simulation of turbulence in flows characterized by natural circulation, high Rayleigh numbers and low Reynolds numbers; validity of heat transfer ...

312

Single and double ionization of strontium in the vicinity of four-photon excitation of the 5p{sup 2} {sup 1}S{sub 0} doubly excited state  

Energy Technology Data Exchange (ETDEWEB)

We report on the single and double multiphoton ionization of ground state Sr atoms observed in an atomic beam experiment with laser pulses of {approx}5 ns duration, maximum intensity {approx}4 x 10{sup 11} W cm{sup -2} and within the 710-740 nm wavelength range. The Sr{sup +} spectrum consists of two strong lines originating from three-photon resonant four-photon ionization of bound states, a number of weak autoionizing resonances and a broad line due to four-photon excitation of the doubly excited 5p{sup 2} {sup 1}S{sub 0} state. The latter, along with a strong, broad and structured spectral feature, is also evident in the wavelength dependence of the doubly charged Sr{sup 2+} ion. A weakly evident but reproducible inflection point ('knee' structure) appears in the intensity dependence of the Sr{sup 2+} yield at the location of the 5p{sup 2} {sup 1}S{sub 0} resonance. A complementary fluorescence experiment revealed the accumulation of population in the 5p{sub ...

2008-02-28

313

Numerical simulation of progressive inlet orifices in boiling water reactor fuel  

International Nuclear Information System (INIS)

This thesis was carried out at Forsmark Nuclear Power Plant. The power plant in Forsmark consists of three boiling water reactors (BWR) which produce about 17% of Swedish electricity. In a BWR the nuclear reactions are used to boil water inside the reactor vessel. The water works both as a coolant and as a moderator and the resulting steam is used directly to run the turbines. A problem when running a BWR at low flow conditions is the density wave oscillations that might occur to the water flow inside the fuel assemblies. These oscillations arise due to the connection between power and flow rate in a heated channel with two-phase flow. In order to improve the stability performance of the channel an orifice plate is placed at the inlet of each fuel assembly. Today these orifice plates have sharp edges and a constant resistance coefficient. Experimental work has been done with progressive orifices, the edge of which is half-oval in shape. The advantage of progressive orifices is the ...

2004-01-01

314

Global Molecular Characterization of the Chromate Stress Response in Shewanella oneidensis MR-1: Identification of a Putative DNA-Binding Response Regulator and Azoreductase Involved in Cr(VI) Detoxification  

Energy Technology Data Exchange (ETDEWEB)

Shewanella oneidensis MR-1 is a model environmental organism that possesses diverse respiratory capacities, including the ability to reduce soluble Cr(VI) to sparingly soluble, less toxic Cr(III). Effective bioremediation of Cr-contaminated sites requires knowledge of the molecular mechanisms and regulation of heavy metal resistance and biotransformation by dissimilatory metal-reducing bacteria. Towards this goal, our ERSP-funded work is focused on the identification and functional analysis of genes/proteins comprising the response pathways for chromate detoxification and/or reduction. Previous transcriptomic profiling and whole-cell proteomic analyses implicated the involvement of a functionally undefined DNA-binding response regulator (SO2426) and a putative azoreductase (SO3585) in the chromate stress response of MR-1. Here we describe a detailed functional analysis of SO2426 and SO3585 in order to begin to understand the role of these proteins in the cellular response to chromate. ...

2006-04-05

315

Determination of As, Cd, Pb, and Hg in urine using inductively coupled plasma mass spectrometry with the direct injection high efficiency nebulizer  

Energy Technology Data Exchange (ETDEWEB)

The application of the large-bore direct injection high efficiency nebulizer (LB-DIHEN) for the determination of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) in urine by inductively coupled plasma mass spectrometry (ICP-MS) is described. The LB-DIHEN is compared with the standard method using a concentric pneumatic nebulizer and cyclonic spray chamber. In addition to the toxicological significance of As, Cd, Pb, and Hg, these elements represent a cross-section of analytical issues including spectral interferences (e.g., {sup 40}Ar{sup 35}Cl{sup +} on {sup 75}As{sup +} and {sup 98}Mo{sup 16}O{sup +} on {sup 114}Cd{sup +}) and memory effects (Hg). In this study, the low sample consumption of the LB-DIHEN is used to reduce the volume of urine needed for analysis, and to reduce the volume of final diluted sample required for analysis. Eliminating the spray chamber and reducing the dead volume of the nebulizer reduces memory effects, especially for analytes such as Hg. The ...

2008-03-15

316

Simulating Large-scale Structure  

CERN Document Server

After two decades of direct dynamical simulation of large-scale structure in the universe, it is safe to say the subject is now mature. Still, there are parts of the problem that are less well developed than others. In general, the collisionless dynamics of the dark matter component is better understood than the collisional gas dynamics of the baryonic component. In situations where the gas dynamics is relatively simple, such as the Lyman-$\\alpha$ forest and the intracluster medium in X-ray clusters, our ability to reproduce observational data has evolved rapidly, and the interpretive and predictive power of such experiments should now be taken seriously. A comparison of twelve gas dynamic codes to the problem of forming a single X-ray cluster shows that numerical inaccuracies are modest (typically below ten percent), leaving missing physics as the main source for large systematic ...

1998-01-01

317

Probabilistic approach for model and data uncertainties and its experimental identification in structural dynamics: Case of composite sandwich panels  

Science.gov (United States)

This paper deals with the experimental identification and the validation of a non-parametric probabilistic approach allowing model uncertainties and data uncertainties to be taken into account in the numerical model developed to predict low- and medium-frequency dynamics of structures. The analysis is performed for a composite sandwich panel representing a complex dynamical system which is sufficiently simple to be completely described and which exhibits, not only data uncertainties, but above all model uncertainties. The dynamical identification is experimentally performed for eight panels. The experimental frequency response functions are used to identify the non-parametric probabilistic approach of model uncertainties. The prediction of the low- and medium-frequency dynamical responses obtained with the stochastic system is compared with the experimental measurements.

2006-06-01

318

Mixmaster: fact and belief  

Energy Technology Data Exchange (ETDEWEB)

We consider the dynamics towards the initial singularity of Bianchi type IX vacuum and orthogonal perfect fluid models with a linear equation of state. Surprisingly few facts are known about the 'Mixmaster' dynamics of these models, while at the same time most of the commonly held beliefs are rather vague. In this paper, we use Mixmaster facts as a base to build an infrastructure that makes it possible to sharpen the main Mixmaster beliefs. We formulate explicit conjectures concerning (i) the past asymptotic states of type IX solutions and (ii) the relevance of the Mixmaster/Kasner map for generic past asymptotic dynamics. The evidence for the conjectures is based on a study of the stochastic properties of this map in conjunction with dynamical systems techniques. We use a dynamical systems formulation, since this approach has so far been the only successful path ...

2009-04-07

319

Scaling of swim speed and stroke frequency in geometrically similar penguins: they swim optimally to minimize cost of transport  

UK PubMed Central (United Kingdom)

It has been predicted that geometrically similar animals would swim at the same speed with stroke frequency scaling with mass−1/3. In the present study, morphological and behavioural...Full Text Available

2010-03-07

320

Comparative evaluation of similarity measures for the rigid registration of multi-modal head images  

Energy Technology Data Exchange (ETDEWEB)

Image registrations that are based on similarity measures simply adjust the parameters of an appropriate spatial transformation model until the similarity measure reaches an optimum. The numerous similarity measures that have been proposed in the past are differently sensitive to imaging modality, image content and differences in the image content, selection of the floating and target image, partial image overlap, etc. In this paper, we evaluate and compare 12 similarity measures for the rigid registration. To study the impact of different imaging modalities on the behavior of similarity measures, we have used 16 CT/MR and 6 PET/MR image pairs with known 'gold standard' registrations. The results for the PET/MR registration and for the registration of CT to both rectified and unrectified MR images indicate that mutual information, normalized mutual information and ...

2007-09-21

321

Evaluation of femoral head perfusion by dynamic MRI  

International Nuclear Information System (INIS)

The purpose of this study was to evaluate the usefulness of dynamic MRI for femoral head perfusion. Objects were 64 femoral heads of 44 normal cases (20-95 years old), 10 cases (33-90 y) of femoral neck fracture and 8 cases (61-86 y) using steroid due to articular rheumatism, nephrosis and other diseases. Siemens 1.0 T Magneton Impact with body array coil was used for dynamic MRI by the fast low-angle shot 2D method for every 17 sec interval. Gd-DTPA was injected intravenously. ROI was defined in the center of femur head and of trochanter to monitor their values for the dynamic curve. Evaluation was done on the ratio of enhancement ratio (ER) in the head/trochanter and on the curve in both heads. In normal cases, the head ER was significantly lower in >60 years old cases. There was neither significant correlation between their head/trochanter ER ratios nor significant difference between their dynamic ...

1998-05-01

322

Survey of Biodegradation of Electronic Components and ...  

Science.gov (United States)

... This pinhole process may be similar to the formation of an oxide layer in aluminum electrolytic capacitors immersed in a borax solution. ...

1991-08-01

323

Search Efficiency in Indexing Structures for Similarity Searching  

CERN Document Server

Similarity searching finds application in a wide variety of domains including multilingual databases, computational biology, pattern recognition and text retrieval. Similarity is measured in terms of a distance function edit distance in general metric spaces, which is expensive to compute. Indexing techniques can be used reduce the number of distance computations. We present an analysis of various existing similarity indexing structures for the same. The performance obtained using the index structures studied was found to be unsatisfactory . We propose an indexing technique that combines the features of clustering with M tree(MTB) and the results indicate that this gives better performance.

2004-01-01

324

ISO TC 20/SC 14 N  

Science.gov (United States)

runs are necessary, provision shall be made for expansion joints, motion of the units, or similar compensation to ensure that no excessive strains are ...

325

The effects of surface damage on RF cavity operation  

Energy Technology Data Exchange (ETDEWEB)

We describe a model of damage in rf cavities and show how this damage can limit cavity operation. We first present a review of mechanisms that may or may not affect the ultimate fields that can be obtained in rf cavities, assuming that mechanical stress explains the triggers of rf breakdown events. We present a method of quantifying the surface damage caused by breakdown events in terms of the spectrum of field enhancement factors, Beta, for asperities on the surface. We then model an equilibrium that can develop between damage and conditioning effects, and show how this equilibrium can determine cavity performance and show experimental evidence for this mechanism. We define three functions that quantify damage, and explain how the parameters that determine this performance can be factored out and measured. We then show how this model can quantitatively explain the dependence of cavity performance on material, frequency, pulse length, gas, ...

2006-04-14

326

The Effects of Exurbanization on Bird and Macro invertebrate Communities in Deciduous Forests on the Cumberland Plateau, Tennessee  

International Nuclear Information System (INIS)

To investigate the potential causes of changes to bird communities in exurban areas, we examined the relationship between bird and macro invertebrate communities in exurbanized forest. We randomly located sampling points across a gradient of exurbanization. We used point counts to quantify bird communities and sweep netting, soil cores, pitfalls, and frass collectors to quantify macro invertebrates. Bird communities had higher richness and abundance in exurban areas compared to undeveloped forests, and lost some species of conservation concern but gained others. The macro invertebrate community was slightly more abundant in exurban areas, with a slight shift in taxonomic composition. The abundance of macro invertebrates in soil cores (but not pitfalls) predicted the abundance of ground-foraging birds. The abundance of macro invertebrates in sweep nets was not associated with the abundance of aerial insectivore birds. Exurbanization therefore ...

327

Second-law efficiency of solar-thermal cavity receivers  

Energy Technology Data Exchange (ETDEWEB)

Properly quantified performance of a solar-thermal cavity receiver must not only account for the energy gains and losses as dictated by the First Law of thermodynamics, but it must also account for the quality of that energy. However, energy quality can only be determined from the Second Law. In this paper an equation for the Second-Law efficiency of a cavity receiver is derived from the definition of available energy or availability (occassionally called exergy), which is a thermodynamic property that measures the maximum amount of work obtainable when a system is allowed to come into unrestrained equilibrium with the surrounding environment. The fundamental concepts of the entropy and availability of radiation are explored from which a convenient relationship among the reflected cone half angle, the insolation, and the concentrator geometric characteristics is developed as part of the derivation of the Second-Law efficiency. A comparison is made between First- ...

1983-10-01

328

Quantification of the local glucose utilization and local blood flow in the heart of the awake rat using the /sup 14/C-2-deoxyglucose and /sup 14/C-iodoantipyrine methods  

Science.gov (United States)

Local cardiac glucose utilization (LCarGU) was quantified in the rat heart according to the Sokoloff model and local cardiac blood flow (LCarBF) according to the /sup 14/C-iodoantipyrine method. For quantitative autoradiography calibration curves for heart slices were performed. They differed from the brain calibration curves by 8%. The lumped constant was 0.377 in isolated working hearts. LCarGU and LCarBF could then be quantified in awake rats. At different locations mean LCarGU of different hearts varied from 85 to 200 ..mu..moles/100g/min and mean LCarBF from 390 to 831 ml/100g/min. The ratio subendocardial/subepicardial glucose utilization or blood flow was not systematically different from 1. The results indicate that glucose can be an important fuel in the heart of the awake rat, although its contribution to overall metabolism varies from animal to animal.

1986-03-05

329

Data report of BWR post-CHF tests. Transient core thermal-hydraulic test program. Contract research  

Energy Technology Data Exchange (ETDEWEB)

JAERI has been performing transient core thermal-hydraulic test program. In the program, authors performed BWR/ABWR DBE simulation tests with a test facility, which can simulate BWR/ABWR transients. The test facility has a 4 x 4 bundle core simulator with 15-rod heaters and one non-heated rod. Through the tests, authors quantified the thermal safety margin for core cooling. In order to quantify the thermal safety margin, authors collected experimental data on post-CHF. The data are essential for the evaluation of clad temperature transient when core heat-up occurs during DBEs. In comparison with previous post-CHF tests, present experiments were performed in much wider experimental condition, covering high clad temperature, low to high pressure and low to high mass flux. Further, data at wider elevation (lower to higher elevation of core) were obtained in the present experiments, which make possible to discuss the effect of axial position on ...

2001-03-01

330

An objective indicator for two-phase flow pattern transition  

Energy Technology Data Exchange (ETDEWEB)

This work concerns the development of a methodology the objective of which is to characterize and diagnose two-phase flow regime transitions. The approach is based on the fundamental assumption that a transition flow is less stationary than a flow with an established regime. During the first time, the efforts focused on: (1) the design and construction of an experimental loop, allowing to reproduce the main horizontal two-phase flow patterns, in a stable and controlled way; (2) the design and construction of an electrical impedance probe, providing an imaged information of the spatial phase distribution in the pipe; and (3) the systematic study of the joint time-frequency and time-scale analysis methods, which permitted to define an adequate parameter quantifying the unstationarity degree. During the second time, in order to verify the fundamental assumption, a series of experiments were conducted, the objective of which was to demonstrate the correlation between ...

1998-08-01

331

An objective indicator for two-phase flow pattern transition  

International Nuclear Information System (INIS)

This work concerns the development of a methodology the objective of which is to characterize and diagnose two-phase flow regime transitions. The approach is based on the fundamental assumption that a transition flow is less stationary than a flow with an established regime. During the first time, the efforts focused on: (1) the design and construction of an experimental loop, allowing to reproduce the main horizontal two-phase flow patterns, in a stable and controlled way; (2) the design and construction of an electrical impedance probe, providing an imaged information of the spatial phase distribution in the pipe; and (3) the systematic study of the joint time-frequency and time-scale analysis methods, which permitted to define an adequate parameter quantifying the unstationarity degree. During the second time, in order to verify the fundamental assumption, a series of experiments were conducted, the objective of which was to demonstrate the correlation between ...

1998-08-01

332

A new method for quantifiable and controlled dosage of particulate matter for in vitro studies: the electrostatic particulate dosage and exposure system (EPDExS).  

Science.gov (United States)

An exposure chamber is described for the quantifiable addition of fine and ultrafine aerosol particulate matter directly to cells and used to demonstrate the in vitro cytotoxicity of fine 1,4-naphthoquinone particles to murine lung epithelial cells. The electrostatic particulate dosage and exposure system (EPDExS) operates on the principle of electrostatic precipitation and is shown to deposit fine and ultrafine aerosol particles directly to cells with 100% efficiency for particle diameters in the range of 40-530nm. This range is not limited by the EPDExS, but rather by the aerosolization method used for this study. Numbers of particles deposited onto the cells are counted with a condensation particle counter, negating any need to calculate or estimate particle exposure. The process of particle introduction, assessed using Trypan blue dye exclusion, had no effect on cell viability. In combination with a differential mobility classifier, the EPDExS can deliver ...

2008-06-08

333

A carbon monoxide passive sampler: Research and development needs  

Energy Technology Data Exchange (ETDEWEB)

In rare instances, carbon monoxide (CO) levels in houses can reach dangerously high concentrations, causing adverse health effects ranging from mild headaches to, under extreme conditions, death. Hundreds of fatal accidental carbon monoxide poisonings occur each year primarily due to the indoor operation of motor vehicles, the indoor use of charcoal for cooking, the operation of malfunctioning vented and unvented combustion appliances, and the misuse combustion appliances. Because there is a lack of simple, inexpensive, and accurate field sampling instrumentation, it is difficult for gas utilities and researchers to conduct field research studies designed to quantify the concentrations of CO in residences. Determining the concentration of CO in residences is the first step towards identifying the high risk appliances and high-CO environments which pose health risks. Thus, there exists an urgent need to develop and field-validate a ...

1991-11-01

334

Universal Similarity  

CERN Document Server

We survey a new area of parameter-free similarity distance measures useful in data-mining, pattern recognition, learning and automatic semantics extraction. Given a family of distances on a set of objects, a distance is universal up to a certain precision for that family if it minorizes every distance in the family between every two objects in the set, up to the stated precision (we do not require the universal distance to be an element of the family). We consider similarity distances for two types of objects: literal objects that as such contain all of their meaning, like genomes or books, and names for objects. meaning, like genomes or books, and names for objects. The latter may have literal embodyments like the first type, but may also be abstract like ``red'' or ``christianity.'' For the first type we consider a family of computable distance measures corresponding to parameters expressing similarity according to ...

2005-01-01

335

Visible and near-infrared spectral signatures for adulteration assessment of extra virgin olive oil  

Science.gov (United States)

Because of its high price, the extra virgin olive oil is frequently target for adulteration with lower quality oils. This paper presents an innovative optical technique capable of quantifying the adulteration of extra virgin olive oil caused by lowergrade olive oils. It relies on spectral fingerprinting the test liquid by means of diffuse-light absorption spectroscopy carried out by optical fiber technology in the wide 400-1700 nm spectral range. Then, a smart multivariate processing of spectroscopic data is applied for immediate prediction of adulterant concentration.

2010-04-01

336

Use of activated charcoal for the purification of neon in the CLEAN experiment  

Energy Technology Data Exchange (ETDEWEB)

Passage of neon gas through activated charcoal is planned to be the primary method of removing impurities from the liquid neon scintillator in the CLEAN experiment. In order to quantify this technique, the breakout curves for hydrogen, nitrogen, argon and krypton impurities in neon-saturated activated charcoal were measured. Adsorption coefficients and the number of theoretical stages were measured for hydrogen in the temperature range between 300 and 80 K, nitrogen between 300 and 200 K, and argon between 300 and 190 K. The adsorption coefficient for krypton was measured at 300 K.

2007-01-21

337

Upgraded coal interest group. Quarterly report, July 1, 1995--September 30, 1995  

Energy Technology Data Exchange (ETDEWEB)

The objectives of the Upgraded Coal Interest Group (UCIG) are as follows: Review and update the status of various coal upgrading technologies and developments and critically assess the results. Perform engineering screening analyses on various coal upgrading approaches. Perform commercialization analyses that will promote the availability and use of upgraded coal products by quantifying the benefits of using them. Identify market opportunities for introduction of upgraded coals. Perform critical analyses on a variety of coals and technologies in areas important to users but not readily available. Perform critical experiments which will show the differences between technologies.

1995-12-31

338

The new thermal comfort equation to qualify air in buildings. De nieuwe behaaglijkheidsbalans voor de kwaliteit van de lucht in gebouwen  

Energy Technology Data Exchange (ETDEWEB)

In the 1988 February issue of this magazine the units olf and decipol were introduced. Olf is a measure for the pollution load and decipol for the indoor air quality. This article discusses a new ventilation theory which is quantified by the new indoor air quality thermal comfort balance based on the units olf and decipol. This balance requires more ventilation air than for the present regulations. It takes into account all pollution sources. 2 figs., 9 refs., 3 tabs.

1990-05-01

339

Solid-state ozone synthesis by energetic ions  

International Nuclear Information System (INIS)

We have synthesized ozone by irradiating thin solid films of oxygen and oxygen-water mixtures with 100 keV protons, motivated by recent reports of condensed O_3 on icy satellites in the outer Solar system. We measured the depth of the Hartley absorption band in the ultraviolet by reflectance spectroscopy and used it to quantify the column density of ozone. We analyzed the results using a three-component (O, O_2 and O_3) model that successfully explains the fluence dependence of ozone production.

1999-08-02

340

Radiation risk in diagnostic radiology  

International Nuclear Information System (INIS)

An attempt was made to quantify the radiation risk of diagnostic radiology. After a general introduction of terms as radiation damage, radiation risk and effective dose equivalent, based on publications of the ICRP, somatic dose indexes were computed for several radiologic investigations, that comprise organ doses committed to red bone marrow, lung, female breast and thyroid with and without considering the rest of the body. The dose for the rest of the body was assumed to be equal to the dose received by the red bone marrow, that is also distributed over the whole body. Neglecting the exposure of the rest of the body resulted in an insignificant increase in the estimated somatic risk, with its experimental determination not being necessary. (author).

1984-01-01

341

Quantification of uranium transport away from firing sites at Los Alamos National Laboratory: A mass balance approach  

Science.gov (United States)

Investigations were conducted at Los Alamos National Laboratory to quantify the extent of migration of depleted uranium away from firing sites. Extensive sampling of air particles, soil, sediment, and water was conducted to establish the magnitude of uranium contamination throughout one watershed. The uranium source term was estimated, and mass balance calculations were performed to compare the percentage of migrated uranium with original expenditures. Mass balance calculations can be powerful in identification of the extent of waste migration and used as an aid in planning future waste investigations.

1992-02-01

342

Low-level and transuranic waste transportation, disposal, and facility decommissioning cost sensitivity analysis  

Energy Technology Data Exchange (ETDEWEB)

The Systems Design Study (SDS) identified technologies available for the remediation of low-level and transuranic waste stored at the Radioactive Waste Management Complex's Subsurface Disposal Area at the Idaho National Engineering Laboratory. The SDS study intentionally omitted the costs of transportation and disposal of the processed waste and the cost of decommissioning the processing facility. This report provides a follow-on analysis of the SDS to explore the basis for life-cycle cost segments of transportation, disposal, and facility decommissioning; to determine the sensitivity of the cost segments; and to quantify the life-cycle costs of the 10 ex situ concepts of the Systems Design Study.

1992-05-01

343

Low-level and transuranic waste transportation, disposal, and facility decommissioning cost sensitivity analysis  

Energy Technology Data Exchange (ETDEWEB)

The Systems Design Study (SDS) identified technologies available for the remediation of low-level and transuranic waste stored at the Radioactive Waste Management Complex`s Subsurface Disposal Area at the Idaho National Engineering Laboratory. The SDS study intentionally omitted the costs of transportation and disposal of the processed waste and the cost of decommissioning the processing facility. This report provides a follow-on analysis of the SDS to explore the basis for life-cycle cost segments of transportation, disposal, and facility decommissioning; to determine the sensitivity of the cost segments; and to quantify the life-cycle costs of the 10 ex situ concepts of the Systems Design Study.

1992-05-01

344

Intergranular corrosion of Alloy 800 by the electrochemical potentiokinetic reactivation method  

Energy Technology Data Exchange (ETDEWEB)

The 'Electrochemical Potentiokinetic Reactivation' method has been employed to quantify the degree of intergranular corrosion of Alloy 800, with different Ti + Al content, aged in the range 500-650/sup 0/C for times up to 5000 hours. The results were compared with the classical Rollason's curves obtained by means of the Strauss' test and a satisfactory agreement was found. An explanation of the slight differences between both methods has been proposed on the basis of the passivity film morphology.

1981-08-01

345

Hideout return testing from support crevices  

International Nuclear Information System (INIS)

The objectives of the project were to develop operational techniques for promoting contaminant hideout return from tube support crevices and to identify the effect of chemical inhibitor application on corrodent transport. The implementation of routine procedures for promoting the return of sequestered corrodents could retard the progression of denting or other corrosion processes and improve steam generator availability. Tests also quantified the effect of inhibitor application on crevice hideout and hideout return processes, with the intention of developing a better understanding of the inhibition mechanism. By carefully monitoring the hideout and hideout return inventories, the program also has provided the opportunity to study steam generator concentration processes in general.

1985-03-01

346

Experimental Uncertainty for the Thermal Expansion of a Simulated Fuel  

Energy Technology Data Exchange (ETDEWEB)

Thermal expansions of a simulated fuel (SS-1) were measured by using a Dilatometer (DIL402C) from room temperature to 1900 K. The main procedure of an uncertainty evaluation followed the strategy of the UO{sub 2} fuel. Referring to the ISO (International Organization for Standardization) guide, the uncertainties of the thermal expansion were quantified in three parts - the initial length, the length variation, and the system calibration factor. The uncertainty of the thermal expansion for a simulated fuel was also compared with those of UO{sub 2} fuel.

2006-07-01

347

Entangled quantum currents in distant mesoscopic Josephson junctions  

Energy Technology Data Exchange (ETDEWEB)

Two mesoscopic SQUID rings which are far from each other are considered. A source of two-mode nonclassical microwaves irradiates the two rings with correlated photons. The Josephson currents are in this case quantum mechanical operators, and their expectation values with respect to the density matrix of the microwaves yield the experimentally observed currents. Classically correlated (separable) and quantum mechanically correlated (entangled) microwaves are considered, and their effect on the Josephson currents is quantified. Results for two different examples that involve microwaves in number states and coherent states are derived. It is shown that the quantum statistics of the tunnelling electron pairs through the Josephson junctions in the two rings are correlated.

2004-12-22

348

Electron Beam and Gamma Radiolysis of Solid-State Metoclopramide  

British Library Electronic Table of Contents (United Kingdom)

Purpose Study the radiolysis of solid-state metoclopramide hydrochloride at various absorbed doses. Elucidate the structure of the degradation products to gain information on the radiolysis mechanisms. Methods Solid-state metoclopramide samples were irradiated at several doses with gamma rays and high-energy electrons to evaluate the influence of the dose rate. High-performance liquid chromatography with a diode array detector was used to measure the chemical potency as a function of the absorbed dose and to quantify the degradation products. The characterization of degradation products was performed by liquid chromatography/atmospheric pressure chemical ionization/tandem mass spectrometry. Results The degradation of solid-state metoclopramide after irradiation was negligible. No qualitati...

2006-01-01

349

Comparison of the TESLA, NLC and CLIC Beam-Collimation System Performance  

CERN Document Server

This report describes studies performed in the framework of the Collimation Task Force organized to support the work of the second International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam-halo and synchrotron-radiation collimation efficiency. The performance of the current designs varies across projects, and does not always meet the original design goals. But these comparisons suggest that achieving the required performance in a future linear collider is feasible.

2004-01-01

350

Commercial Credit Value Evaluation and Illustration Analysis on Internet  

Science.gov (United States)

Taobao website online transaction evaluation has been well accepted, but its value has not been measured. This paper quantifies the value of commercial credit of salers in bringing sale purchase on Taobao website through three aspects of data as credit score buyer to saler, number of comments and rate of bad comments. The illustration results on Taobao online transaction credit evaluation show that number of comments, credit score and rate of bad comments have significant impact on sale revenue.

2011-01-01

351

Climate change - the contribution from air travel  

International Nuclear Information System (INIS)

The paper discusses the Intergovernment Panel on Climate Change (IPCC) report on Aviation and the Global Atmosphere (published in 1999). It was considered necessary to treat air transport on its own since aircraft are unique in delivering emissions into the upper atmosphere rather than at ground level. The study was commissioned at the request of the International Civil Aviation Organisation and the Montreal Protocol. More than 300 experts contributed and the report has quantified the effect of aviation on the atmosphere on a world wide basis and highlighted areas where improved data are required. (UK)

2000-04-01

352

Characterization of Mixed Wettability at Different Scales and its Impact on Oil Recovery Efficiency  

Energy Technology Data Exchange (ETDEWEB)

The objectives of this project was to: (1) quantify the pore scale mechanisms that determine the wettability state of a reservoir, (2) study the effect of crude oil, brine and mineral compositions in the establishment of mixed wet states, (3) clarify the effect of mixed - wettability on oil displacement efficiency in waterfloods, (4) develop a new tracer technique to measure wettability, fluid distributions, residual saturation's and relative permeabilities, and (5) develop methods for properly incorporating wettability in up-scaling from pore to core to reservoir scales.

2002-01-28

353

Chandler Slavin | Greener Package  

Wastenet

...it only highlights the different feedstocks used in the production of fiber-based packaging materials or fossil-fuel ones; what about the energy required to convert ...feedstock, is unacceptable in trying to quantify the overall burden a specific packaging material has on the environment. As an aside, the point ... Consequentially, it is difficult to speculate on how much packaging material a company diverts from the landfill by switching from one material to another ...without specifying what geographical region said packaging material resides in. In addition, there is a lot of interest in diverting PET thermoforms from ...

354

AFS Cupola Model Verification--Initial Investigations  

Science.gov (United States)

The cupola furnace is used to melt scrap steel, pig iron, foundry returns, and alloying additives to a prescribed tapping chemistry and temperature for iron casting applications. The melting process within the cupola is highly complex and not well quantified. The American Foundrymen's Society is developing a mathematical model to aid in the understanding of these processes. This model is reaching maturity, and has been successful in estimating a number of melting parameters. This paper details the results of efforts to verify the model in a controlled system, equipped wit the appropriate sensors, for model verification. The work was performed on a research-scale cupola furnace located at the Department of Energy's Albany Research Center.

1998-01-01

355

A quantitative method to detect explosives and selected semivolatiles in soil samples by Fourier transform infrared spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a novel Fourier transform infrared (FTIR) spectroscopic method that can be used to rapidly screen soil samples from potentially hazardous waste sites. Samples are heated in a thermal desorption unit and the resultant vapors are collected and analyzed in a long-path gas cell mounted in a FTIR. Laboratory analysis of a soil sample by FTIR takes approximately 10 minutes. This method has been developed to identify and quantify microgram concentrations of explosives in soil samples and is directly applicable to the detection of selected volatile organics, semivolatile organics, and pesticides.

1995-06-01

356

A mathematical model for simulating shallow solar ponds for treatment of industrial wastewater  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a mathematical model to analyze the solar evaporation in a shallow pond in steady state, when the inlet flow rate, concentration, surface area and solar radiation are given. The simultaneous heat and mass transfer mechanisms are considered for quantifying the amount of evaporated water to the atmosphere and the actual absorbed heat by wastewater is calculated to obtain the bottom temperature of water pond. The heat losses to air by radiation and convection mechanisms are considered and the heat transmission across the water film is evaluated by the forced convection mechanism. 6 refs., 5 figs., 1 tab.

1996-12-31

357

A Virtual Young's Double Slit Experiment for Hard X-ray Photons  

CERN Document Server

We have implemented a virtual Young's double slit experiment for hard X-ray photons with micro-fabricated bi-prisms. We observe fringe patterns with a scintillator, and quantify interferograms by detecting X-ray fluorescence from a scanned 30nm Cr metal film. The observed intensities are best modeled with a near-field, Fresnel analysis. The maximum fringe number in the overlap region is proportional to the ratio of real to imaginary parts refractive index of the prism material. The horizontal and vertical transverse coherence lengths at beamline APS 8-ID are measured.

2009-01-01

358

Spent fuel sabotage aerosol ratio program : FY 2004 test and data summary  

International Nuclear Information System (INIS)

This multinational, multi-phase spent fuel sabotage test program is quantifying the aerosol particles produced when the products of a high energy density device (HEDD) interact with and explosively particulate test rodlets that contain pellets of either surrogate materials or actual spent fuel. This program has been underway for several years. This program provides data that are relevant to some sabotage scenarios in relation to spent fuel transport and storage casks, and associated risk assessments. The program also provides significant technical and political benefits in international cooperation. We are quantifying the Spent Fuel Ratio (SFR), the ratio of the aerosol particles released from HEDD-impacted actual spent fuel to the aerosol particles produced from surrogate materials, measured under closely matched test conditions, in a contained test chamber. In addition, we are measuring the amounts, nuclide content, size distribution of the ...

359

Quantifying regenerator thermal shorting; Bestimmung des thermischen Kurzschlusses von Regeneratorgeweben  

Energy Technology Data Exchange (ETDEWEB)

The regenerator of Stirling cycle machines has an relatively unknown potential for thermal shorting, because the thermal flow path within the solid of a randomly stacked wire mesh, which is defined by its 'connectivity', is unknown. Earlier publications have shown two principles of experimental techniques to quantify connectivity. One quantifies connectivity as a function of axial pressure using the electric current analogy, the other measures connectivity via the temperature gradients along a regenerator and a series-connected reference body of known conductivity. Both papers offer preliminary results of reduced usefulness related to the testing method or setup. This contribution describes a new setup and its technique, which results from the practical knowledge and experience of the first two attempts, and aims for an improved determination of connectivity of the original representative Stirling regenerators with and without ...

2000-07-01

360

Solar wind driving of magnetospheric ULF waves: Field line resonances driven by dynamic pressure fluctuations  

CERN Document Server

Several observational studies suggest that solar wind dynamic pressure fluctuations can drive magnetospheric ultra-low frequency (ULF) waves on the dayside. To investigate this causal relationship, we present results from Lyon-Fedder-Mobarry (LFM) global, three-dimensional magnetohydrodynamic (MHD) simulations of the solar wind-magnetosphere interaction. These simulations are driven with synthetic solar wind input conditions, where idealized ULF dynamic pressure fluctuations are embedded in the upstream solar wind. In three of the simulations, a monochromatic, sinusoidal ULF oscillation is introduced into the solar wind dynamic pressure time series. In the fourth simulation, a continuum of ULF fluctuations over the 0-50 mHz frequency band is introduced into the solar wind dynamic pressure time series. In this numerical experiment, the idealized solar wind input conditions allow us to study only the ...

2010-01-01

361

Nonlinear dynamics of a flexible rotor supported by turbulent journal bearings with couple stress fluid  

Energy Technology Data Exchange (ETDEWEB)

This study presents a dynamic analysis of a rotor supported by two turbulent flow model journal bearings and lubricated with couple stress fluid under nonlinear suspension. The dynamics of the rotor center and bearing center is studied. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The results show that the values of dimensionless parameters l* strongly influence dynamic motions of bearing and rotor centre. It is found that couple stress fluid improve the stability of the system when l* > 0.4 even if the flow of this system is turbulent. We also demonstrated that the dimensionless rotational ...

2008-08-15

362

Nonlinear dynamics of a flexible rotor supported by turbulent journal bearings with couple stress fluid  

International Nuclear Information System (INIS)

This study presents a dynamic analysis of a rotor supported by two turbulent flow model journal bearings and lubricated with couple stress fluid under nonlinear suspension. The dynamics of the rotor center and bearing center is studied. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The results show that the values of dimensionless parameters l* strongly influence dynamic motions of bearing and rotor centre. It is found that couple stress fluid improve the stability of the system when l* > 0.4 even if the flow of this system is turbulent. We also demonstrated that the dimensionless rotational ...

2008-08-01

363

Matter and dynamics in closed cosmologies  

International Nuclear Information System (INIS)

To systematically analyze the dynamical implications of the matter content in cosmology, we generalize earlier dynamical systems approaches so that perfect fluids with a general barotropic equation of state can be treated. We focus on locally rotationally symmetric Bianchi type IX and Kantowski-Sachs orthogonal perfect fluid models, since such models exhibit a particularly rich dynamical structure and also illustrate typical features of more general cases. For these models, we recast Einstein's field equations into a regular system on a compact state space, which is the basis for our analysis. We prove that models expand from a singularity and recollapse to a singularity when the perfect fluid satisfies the strong energy condition. When the matter source admits Einstein's static model, we present a comprehensive dynamical description, which includes the qualitative asymptotic behavior, of models in the ...

2005-04-15

364

The ACR Model: A Multivariate Dynamic Mixture Autoregression  

British Library Electronic Table of Contents (United Kingdom)

Abstract This paper proposes and analyses the autoregressive conditional root (ACR) time-series model. This multivariate dynamic mixture autoregression allows for non-stationary epochs. It proves to be an appealing alternative to existing nonlinear models, e.g. the threshold autoregressive or Markov switching class of models, which are commonly used to describe nonlinear dynamics as implied by arbitrage in presence of transaction costs. Simple conditions on the parameters of the ACR process and its innovations are shown to imply geometric ergodicity, stationarity and existence of moments. Furthermore, consistency and asymptotic normality of the maximum likelihood estimators are established. An application to real exchange rate data illustrates the analysis.

2008-01-01

365

Safety design guide for pipe rupture protection for CANDU 9  

Energy Technology Data Exchange (ETDEWEB)

This safety design guide for pipe rupture protection identifies high-energy systems in which pipe ruptures must be postulated to occur, as well as systems that must be protected from the dynamic effects of such ruptures. Dynamic effects considered in this SDG consist of pipe whip (including missiles generated by pipe ruptures, if any) and jet impingement, Requirements for protection against the dynamic effects of a postulated pipe rupture and method of protection of essential structures, systems and components are specified for these effects. The change status for the regulatory requirements, code and standards should be traced and this safety design guide shall be updated accordingly. 2 tabs., 5 refs. (Author) .new.

1996-03-01

366

Nonlinear evolution of coarse-grained quantum systems with generalized purity constraints  

CERN Document Server

Constrained quantum dynamics is used to propose a nonlinear dynamical equation for pure states of a generalized coarse-grained system. The relevant constraint is given either by the generalized purity or by the generalized invariant fluctuation, and the coarse-grained pure states correspond to the generalized coherent i.e. generalized nonentangled states. Open system model of the coarse-graining is discussed. It is shown that in this model and in the weak coupling limit the constrained dynamical equations coincide with an equation for pointer states, based on Hilbert-Schmidt distance, that was previously suggested in the context of the decoherence theory.

2010-01-01

367

Nonlinear dynamics of heat transfer enhancement using eddy promoters  

Science.gov (United States)

This investigation concerns the nonlinear dynamics of heat transfer from a surface using an upstream eddy promoter. A numerical model is developed for the coupled fluid flow and heat transfer process based on a modified MacCormack scheme. Numerical simulations are carried out to determine the response and heat transfer enhancement due to the promoter. The average heat transfer from a cavity floor is seen to be increased by a factor of approximately five over the unpromoted'' flow. Another interesting feature of the study is the nonlinear viscous flow dynamics from the cylinder-wall interaction which differ significantly from the familiar cylinder-free stream patterns.

1994-02-01

368

Nonlinear dynamics of heat transfer enhancement using eddy promoters  

Energy Technology Data Exchange (ETDEWEB)

This investigation concerns the nonlinear dynamics of heat transfer from a surface using an upstream eddy promoter. A numerical model is developed for the coupled fluid flow and heat transfer process based on a modified MacCormack scheme. Numerical simulations are carried out to determine the response and heat transfer enhancement due to the promoter. The average heat transfer from a cavity floor is seen to be increased by a factor of approximately five over the unpromoted'' flow. Another interesting feature of the study is the nonlinear viscous flow dynamics from the cylinder-wall interaction which differ significantly from the familiar cylinder-free stream patterns.

1994-02-01

369

Centroid and Envelope Dynamics of High-intensity Charged Particle Beams in an External Focusing Lattice and Oscillating Wobbler  

Energy Technology Data Exchange (ETDEWEB)

The centroid and envelope dynamics of a high-intensity charged particle beam are investigated as a beam smoothing technique to achieve uniform illumination over a suitably chosen region of the target for applications to ion-beam-driven high energy density physics and heavy ion fusion. The motion of the beam centroid projected onto the target follows a smooth pattern to achieve the desired illumination, for improved stability properties during the beam-target interaction. The centroid dynamics is controlled by an oscillating "wobbler", a set of electrically-biased plates driven by RF voltage. __________________________________________________

2010-04-28

370

Application of the IPEBS method to dynamic contingency analysis  

Energy Technology Data Exchange (ETDEWEB)

Dynamic contingency analysis is certainly a demanding task in the context of dynamic performance evaluation. This paper presents the results of a test for checking the contingency screening capability of the IPEBS method. A brazilian 1100-bus, 112-gen system was used in the test; the ranking of the contingencies based on critical clearing times obtained with IPEBS, was compared with the ranking derived from detailed time-domain simulation. The results of this comparison encourages us to recommended the use of the method in industry applications, in a complementary basis to the current method of time domain simulation. (author) 5 refs., 1 fig., 2 tabs.

1994-12-31

371

A multi agent model for the limit order book dynamics  

Science.gov (United States)

In the present work we introduce a novel multi-agent model with the aim to reproduce the dynamics of a double auction market at microscopic time scale through a faithful simulation of the matching mechanics in the limit order book. The agents follow a noise decision making process where their actions are related to a stochastic variable, the market sentiment, which we define as a mixture of public and private information. The model, despite making just few basic assumptions over the trading strategies of the agents, is able to reproduce several empirical features of the high-frequency dynamics of the market microstructure not only related to the price movements but also to the deposition of the orders in the book.

2010-11-01

372

Workshop on Dynamics and Aeroelastic Stability Modeling of ...  

Science.gov (United States)

... Each beam finite element was derived using Hamilton's principle and the following basic assumptions: the beam has an arbitrary amount of pretwist ...

1990-03-14

373

Vibratory Dynamics of Flow-Excited Struts in Water  

Science.gov (United States)

... The lateral cross spectral density measurements are normalized on the autospectrum. Frequency is normalized on r3 , and we take Uc _" 0.7 U0 . ...

1973-12-01

374

Ultrafast fluorescence dynamics of Sybr Green I/DNA complexes  

British Library Electronic Table of Contents (United Kingdom)

The ultrafast dynamics of the DNA fluorescent dye Sybr Green I (SG) has been studied in buffer, single-stranded (ssDNA), double-stranded (dsDNA) and triple-stranded DNA (tsDNA). The fluorescence quantum yield of SG increases dramatically when bound to DNA (including tsDNA). The fluorescence dynamics of the free SG has shown two decay components with 0.15-0.4ps and 1.3-2.1ps time constants, depending on the fluorescence wavelength. Upon binding to DNA, the dynamics becomes slower exhibiting four decay components. This is mainly due to the restriction of the internal motions of the dye caused by the relatively rigid environment of the dye complexed with DNA.

2010-01-01

375

Transient Fluid Dynamics of the Quark-Gluon Plasma According to AdS/CFT  

CERN Document Server

We prove, using the AdS/CFT correspondence, that the long wavelength dynamics of the shear stress tensor in a strongly coupled N=4 SYM plasma is not described by the relaxation-type, fluid dynamical equations proposed by Israel and Stewart: the coarse grained dynamics will necessarily contain a second-order comoving derivative of the shear stress tensor. We argue that this should be true for any strongly-coupled gauge theory with a gravity dual. If the QGP formed in heavy ion collisions can indeed be described in terms of a (yet unknown) theory of gravity in higher dimensions, the equations of motion used in hydrodynamical simulations of the QGP must necessarily include second order comoving derivatives of the shear stress tensor.

2011-01-01

376

The role of large-scale, extratropical dynamics in climate change  

Energy Technology Data Exchange (ETDEWEB)

The climate modeling community has focused recently on improving our understanding of certain processes, such as cloud feedbacks and ocean circulation, that are deemed critical to climate-change prediction. Although attention to such processes is warranted, emphasis on these areas has diminished a general appreciation of the role played by the large-scale dynamics of the extratropical atmosphere. Lack of interest in extratropical dynamics may reflect the assumption that these dynamical processes are a non-problem as far as climate modeling is concerned, since general circulation models (GCMs) calculate motions on this scale from first principles. Nevertheless, serious shortcomings in our ability to understand and simulate large-scale dynamics exist. Partly due to a paucity of standard GCM diagnostic calculations of large-scale motions and their transports of heat, momentum, potential vorticity, and ...

1994-02-01

377

The Natural Statistics of Audiovisual Speech  

UK PubMed Central (United Kingdom)

Humans, like other animals, are exposed to a continuous stream of signals, which are dynamic, multimodal, extended, and time varying in nature. This complex input space must be transduced and sampled...Full Text Available

2009-07-01

378

The I3I Model; Identifying Cultural Determinants of Information ...  

Science.gov (United States)

... Information behavior in dynamic group work contexts: Interwoven situational awareness, dense social networks and contested collaboration in ...

2009-06-01

379

The Growth Cone Cytoskeleton in Axon Outgrowth and Guidance  

UK PubMed Central (United Kingdom)

Axon outgrowth and guidance to the proper target requires the coordination of filamentous (F)-actin and microtubules (MTs), the dynamic cytoskeletal polymers that promote shape change and locomotion....Full Text Available

380

Sunflower i condenser-subcooler topical re- port, jun. 1960 - aug. 1962  

Science.gov (United States)

Fluid dynamic design criteria for mercury condenser-subcooler component for sunflower power conversion system

1964-01-01

381

Study of ebullated bed fluid dynamics for H-Coal. Quarterly progress report No. 2, December 1, 1977--February 28, 1978  

Science.gov (United States)

The H-Coal ebullated bed reactor contains at least four discrete components: gas, liquid, catalyst, and unconverted coal and ash. Because of the complexity created by these four components, it is desirable to understand the fluid dynamics of the system. The objective of this program is to establish the dependence of the ebullated bed fluid dynamics on process parameters. This will permit improved control of the ebullated bed reactor. Progress has been made in the study undertaken for defining the hydrodynamic properties of gas/liquid/solid systems as related to the H-Coal process. The literature search was completed, and a report will be issued shortly. Design and construction of the fluid dynamics unit proceeded as planned. Unit completion is scheduled for May 1, 1978.

1978-03-01

382

Structure, mechanical properties, and dynamic fracture in nanophase silicon nitride via parallel molecular dynamics  

Energy Technology Data Exchange (ETDEWEB)

Million-atom molecular-dynamics (MD) simulations are performed to study the structure, mechanical properties, and dynamic fracture in nanophase Si{sub 3}N{sub 4}. The authors find that intercluster regions are highly disordered: 50% of Si atoms in intercluster regions are three-fold coordinated. Elastic moduli of nanophase Si{sub 3}N{sub 4} as a function of grain size and porosity are well described by a multiphase model for heterogeneous materials. The study of fracture in the nanophase Si{sub 3}N{sub 4} reveals that the system can sustain an order-of-magnitude larger external load than crystalline Si{sub 3}N{sub 4}. This is due to branching and pinning of the crack front by nanoscale microstructures.

1997-09-01

383

Stereochemistry and dynamic study of gamma-lactones derived from D-Mannitol. Part I  

International Nuclear Information System (INIS)

2001 p. 267-268 Brazil Perry, Katia SP Ferreira, Andre RG Amorim, Mauro

2001-05-07

384

Spread dynamics of invasive species  

UK PubMed Central (United Kingdom)

Species invasions are a principal component of global change, causing large losses in biodiversity as well as economic damage. Invasion theory attempts to understand and predict invasion success and...Full Text Available

2006-01-10

385

Scheduling Policies for an Antiterrorist Surveillance System  

Science.gov (United States)

... terminals, popular tourist spots, political rallies, and subway ... Dynamic scheduling of a two-class queue with ... Stochastic Processes 2nd ed. Wiley. ...

2008-06-27

386

Reconfigurations dynamiques de services dans un intergiciel a composants CORBA CCM  

CERN Document Server

Today, component oriented middlewares are used to design, develop and deploy easily distributed applications, by ensuring the heterogeneity, interoperability, and reuse of the software modules, and the separation between the business code encapsulated in the components and the system code managed by the containers. Several standards answer this definition such as: CCM (CORBA Component Model), EJB (Enterprise Java Beans) and .Net. However these standards offer a limited and fixed number of system services, removing any possibility to add system services or to reconfigure dynamically the middleware. Our works propose mechanisms to add and to adapt dynamically the system services, based on a reconfiguration language which is dynamically adaptable to the need of the reconfiguration, and on a tool of dynamic reconfiguration, a prototype was achieved for the OpenCCM platform, that is an implementation of the ...

2004-01-01

387

Real-time neutron radiography applications in dynamic fluid flow studies  

Energy Technology Data Exchange (ETDEWEB)

Real-time neutron radiography (RTNR) is now proving to be a valuable research tool in the study of hydrogenous fluid flow. One of the most significant advantages of neutron radiography is the ability to image hydrogenous substances (such as lubricants, coolants, and fuels) inside metallic materials such as aluminum and titanium engines. By using RTNR, one can then study dynamic events such as the movement of liquids inside these solids. The Phoenix Memorial Laboratory (PML) at the University of Michigan has recently developed and installed a facility dedicated to RTNR. The work at PML has shown that RTNR of dynamic events can provide information enabling the researcher to follow dynamic events that were previously impossible or impractical. This paper will show the variety of uses of RTNR presently being pursued at PML.

1986-01-01

388

Real-time neutron radiography applications in dynamic fluid flow studies  

International Nuclear Information System (INIS)

Real-time neutron radiography (RTNR) is now proving to be a valuable research tool in the study of hydrogenous fluid flow. One of the most significant advantages of neutron radiography is the ability to image hydrogenous substances (such as lubricants, coolants, and fuels) inside metallic materials such as aluminum and titanium engines. By using RTNR, one can then study dynamic events such as the movement of liquids inside these solids. The Phoenix Memorial Laboratory (PML) at the University of Michigan has recently developed and installed a facility dedicated to RTNR. The work at PML has shown that RTNR of dynamic events can provide information enabling the researcher to follow dynamic events that were previously impossible or impractical. This paper will show the variety of uses of RTNR presently being pursued at PML.

1986-11-16

389

Quantitation of Cellular Dynamics in Growing Arabidopsis Roots with Light Sheet Microscopy  

CERN Document Server

To understand dynamic developmental processes, living tissues must be imaged frequently and for extended periods of time. Root development is extensively studied at cellular resolution to understand basic mechanisms underlying pattern formation and maintenance in plants. Unfortunately, ensuring continuous specimen access, while preserving physiological conditions and preventing photo-damage, poses major barriers to measurements of cellular dynamics in indeterminately growing organs such as plant roots. We present a system that integrates optical sectioning through light sheet fluorescence microscopy with hydroponic culture that enables us to image at cellular resolution a vertically growing Arabidopsis root every few minutes and for several consecutive days. We describe novel automated routines to track the root tip as it grows, track cellular nuclei and identify cell divisions. We demonstrate the system's capabilities by collecting data on ...

2011-01-01

391

Optimal Dynamical Range of Excitable Networks at Criticality  

CERN Document Server

A recurrent idea in the study of complex systems is that optimal information processing is to be found near bifurcation points or phase transitions. However, this heuristic hypothesis has few (if any) concrete realizations where a standard and biologically relevant quantity is optimized at criticality. Here we give a clear example of such a phenomenon: a network of excitable elements has its sensitivity and dynamic range maximized at the critical point of a non-equilibrium phase transition. Our results are compatible with the essential role of gap junctions in olfactory glomeruli and retinal ganglionar cell output. Synchronization and global oscillations also appear in the network dynamics. We propose that the main functional role of electrical coupling is to provide an enhancement of dynamic range, therefore allowing the coding of information spanning several orders of magnitude. The mechanism could provide a microscopic ...

2006-01-01

392

Network Security Mechanisms Utilizing Dynamic Network Address Translation LDRD Project  

Science.gov (United States)

A new protocol technology is just starting to emerge from the laboratory environment. Its stated purpose is to provide an additional means in which networks, and the services that reside on them, can be protected from adversarial compromise. This report has a two-fold objective. First is to provide the reader with an overview of this emerging Dynamic Defenses technology using Dynamic Network Address Translation (Dynat). This ''structure overview'' is concentrated in the body of the report, and describes the important attributes of the technology. The second objective is to provide a framework that can be used to help in the classification and assessment of the different types of dynamic defense technologies along with some related capabilities and limitations. This information is primarily contained in the appendices.

2002-11-01

393

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS - NASA Technical ...  

Science.gov (United States)

By H. J. Grover, TV.S. Hyler, Paul Kuhn, Charles B. Landers, and ...... E. Watkins. The Effects on Dynamic Lateral Stability and Control of ...

394

N92-22530 - NASA Technical Report Server (NTRS)  

Science.gov (United States)

and Watkins,. W.B.: Further. Development of the Dynamic. Gas Temperature. Measurement ...... Grover, ed.,. SPIE. Proc. Vol. 954, Society of Photo-Optical ...

395

Multifractal Analysis of Multiple Ergodic Averages  

CERN Document Server

In this paper we present a complete solution to the problem of multifractal analysis of multiple ergodic averages in the case of symbolic dynamics for functions of two variables depending on the first coordinate.

2011-01-01

396

Modeling and numerical simulation of linear and nonlinear spacecraft attitude dynamics and gravity gradient moments: A comparative study  

British Library Electronic Table of Contents (United Kingdom)

In this paper linear and nonlinear models of spacecraft attitude dynamics equations and gravity gradient moments are investigated. In addition, effects of gravity gradient moments on attitude dynamics of the satellite are studied. The purpose of this paper is to present a comparison between nonlinear and linear models of spacecraft attitude dynamics and gravity gradient moments in order to determine divergence of linear approximation from the nonlinear model. Simulation results indicate that designer of spacecraft attitude control subsystem should be meticulous in applying linear approximation of equations especially in low earth orbits. Consequently, finding an upper bound for small angle to keep the linear model valid and precise enough would be a vital part of using linear approximation...

2012-01-01

397

Modeling and Control of Airport Queueing Dynamics under Severe ...  

Science.gov (United States)

air traffic controllers at BOS tower and Terminal Radar Ap- .... Runway ) @ Runway. Buffer. Queue. Runway. Stochastic Delay. (M/1 server). (Runway to Fix). ,I, ...

398

MCRLTER: Coral Reef: Population Dynamics: Monitoring Symbiodinium populations in corals of Moorea  

Science.gov (United States)

Coral are symbiotic with photosynthetic dinoflagellates from the genus Symbiodinium. There are eight divergent clades (A-H) within the genus which each ... ...

399

Jacobi stability analysis of dynamical systems -- applications in gravitation and cosmology  

CERN Document Server

The Kosambi-Cartan-Chern (KCC) theory represents a powerful mathematical method for the analysis of dynamical systems. In this approach one describes the evolution of a dynamical system in geometric terms, by considering it as a geodesic in a Finsler space. By associating a non-linear connection and a Berwald type connection to the dynamical system, five geometrical invariants are obtained, with the second invariant giving the Jacobi stability of the system. The Jacobi (in)stability is a natural generalization of the (in)stability of the geodesic flow on a differentiable manifold endowed with a metric (Riemannian or Finslerian) to the non-metric setting. In the present paper we review the basic mathematical formalism of the KCC theory, and present some specific applications of this method in general relativity, cosmology and astrophysics. In particular we investigate the Jacobi stability of the general relativistic static ...

2010-01-01

400

Influence: Maximizing Effects to Create Long-Term Stability  

Science.gov (United States)

... WHS- Washington Headquarters Service. ... The dynamic Joint Special Operations Task Force -- Philippines (JSOTF-P) has evolved and ...

2010-05-03

401

Hydrodynamics induced vibration to trash-racks  

International Nuclear Information System (INIS)

In conventional power plants trash-racks are provided at the intakes to protect the turbines. In pumped storage plants, the draft tube or tailrace must also have trash-racks to protect the units while pumping. Because the loads believed to cause many failures of trash-racks are dynamic in nature, it is important to understand the dynamic characteristics of trash-racks structures in general and a single rack in particular. The classical added-mass solution structure-fluid dynamic interaction is known as an approximate solution procedure. An accurate added-mass approach mixed with implementation in finite element framework is proposed. In this proposal, experimental conclusions, supported by theory, led to presentation of more accurate results in vibration of trash-racks. This numerical solution as a powerful method to solve such a complex problem can be employed to carry out dynamic characteristics of ...

2002-12-01

402

From Quantitative Microscopy to Automated Image Understanding  

UK PubMed Central (United Kingdom)

Quantitative microscopy has been extensively used in biomedical research and has provided significant insights into structure and dynamics at the cell and tissue level. The entire procedure...Full Text Available

2004-01-01

403

Fractal dynamics in physiology: Alterations with disease and aging  

UK PubMed Central (United Kingdom)

According to classical concepts of physiologic control, healthy systems are self-regulated to reduce variability and maintain physiologic constancy. Contrary to the predictions of homeostasis, however,...Full Text Available

2002-02-19

404

Foveal Machine Vision for Mobile Robots using Agent Based Gaze  

Science.gov (United States)

... non- emissive guidance and collision alert, automated transport in dynamic environments, and assembly and inspection. Foveal Vision, Autonomous Agents, ...

405

Foreign Object Impact Design Criteria. Volume 2  

Science.gov (United States)

... This Level 2 analysis will be somewhat less detailed, but experience in other fields including pipe whip 4 , locomotive dynamics, and nuclear fuel ...

1982-02-01

406

Fluid Transport Phenomena in Ocular Epithelia  

UK PubMed Central (United Kingdom)

This article discusses three largely unrecognized aspects related to fluid movement in ocular tissues; namely, a) the dynamic changes in water permeability observed in corneal and conjunctival...Full Text Available

2008-03-01

407

Existence of a complex closed trajectory in a three-dimensional dynamical system  

British Library Electronic Table of Contents (United Kingdom)

The DN-tracking method is used to prove the existence of a closed trajectory in a quadratic system of ordinary differential equations in three dimensions.

2011-01-01

408

Evaluation of a Biometric Keystroke Typing Dynamics ...  

Science.gov (United States)

... i3a TYPT OF REPORT 13b TIME COVERED 14 DATE OF RF ... automation system when used in conjunction with other standard security measures. ...

1992-03-01

409

Evaluation of CFD to Determine Two-Dimensional Airfoil ...  

Science.gov (United States)

rotor flow field in which the main rotor operates. The majority of ..... early separation predicted by their CFD code was ...... Airfoil, AGARD Fluid Dynamics Panel ...

410

Enterprise Command, Control, and Design: Bridging C2 ...  

Science.gov (United States)

... Information behavior in dynamic group work contexts: interwoven situational awareness, dense social networks and contested collaboration in ...

2011-05-14

411

Energy level schemes and binding energies for nuclei in the region of 140dynamics  

International Nuclear Information System (INIS)

Russian 1987. p. 99-100. USSR Sabalyauskas, L.Yu. Vanagas, VV Guseva,

1987-04-14

412

Effects of Climatic Variability and Land Use on American Drylands...  

Science.gov (United States)

Wildlife Refuge, CA Rare and endangered endemic plants Diana Anderson Northern Arizona University Geomorphology Kathryn Thomas USGS, Flagstaff, AZ Vegetation dynamics John...

2011-09-30

413

Eddy Current Flows Around Cracks in Thin Plates for ...  

Science.gov (United States)

... A few applications, such as magnetic forming and levitation, have exploited the dynamic force pro- ducing capability of eddy currents. ...

1981-03-01

414

Dynamics of southwest Asian dust particle size characteristics with ...  

Science.gov (United States)

dust measured in the Arabian Gulf region during UAE2 and examine the hypothesis that ... [8] UAE2 took place in the southern Arabian Gulf region in August and ...

415

Dynamics of multicomponent vesicles in a viscous fluid  

UK PubMed Central (United Kingdom)

We develop and investigate numerically a thermodynamically consistent model of two-dimensional multicomponent vesicles in an incompressible viscous fluid. The model is derived using an energy...Full Text Available

2010-01-01

416

Dynamic neuronal ensembles: Issues in representing structure change in object-oriented, biologically-based brain models  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the structure of dynamic neuronal ensembles (DNEs). DNEs represent a new paradigm for learning, based on biological neural networks that use variable structures. We present a computational neural element that demonstrates biological neuron functionality such as neurotransmitter feedback absolute refractory period and multiple output potentials. More specifically, we will develop a network of neural elements that have the ability to dynamically strengthen, weaken, add and remove interconnections. We demonstrate that the DNE is capable of performing dynamic modifications to neuron connections and exhibiting biological neuron functionality. In addition to its applications for learning, DNEs provide an excellent environment for testing and analysis of biological neural systems. An example of habituation and hyper-sensitization in biological systems, using a neural circuit from a snail is presented and ...

1996-12-31

417

Dynamic modelling of check valves in shipping terminals; Modelagem dinamica de valvulas de retencao em terminais maritimos  

Energy Technology Data Exchange (ETDEWEB)

As usual a shipping terminal contains a header and its diameter is smaller than the main pipeline diameter. This diameter reduction amplifies the effects caused by hydraulic transients. It was noticed during simulations that check valves without dynamic modeling may introduce some error in the maximum pressure results without a dynamic model approach. The current paper uses commercial pipeline simulation software to model the dynamic behavior of the check valves. It was studied the header diameter influence and how the check valve model type may change the maximum pressure in the pipeline. It was proved that even a pipeline that works with low pressure and small elevation drop needs a detailed valve modeling to prevent the calculation of unreal pressure values in the region with diameter reduction. (author)

2005-07-01

418

Dynamic Weapon-Target Assignment Problems with ...  

Science.gov (United States)

... defense's weapons are Space-based kinetic-kill vehicles ... I ti I obtained by dividing the weapons as ... of the optimal weapon-arge assigntments and ...

1988-06-01

419

Dynamic Phenotypic Clustering in Noisy Ecosystems  

UK PubMed Central (United Kingdom)

In natural ecosystems, hundreds of species typically share the same environment and are connected by a dense network of interactions such as predation or competition for resources. Much is known about...Full Text Available

2011-03-01

420

Dynamic Clamp Analysis of Synaptic Integration in Sympathetic Ganglia  

UK PubMed Central (United Kingdom)

Advances in modern neuroscience require the identification of principles that connect different levels of experimental analysis, from molecular mechanisms to explanations of cellular functions,...Full Text Available

2007-11-01

421

Disorder on the landscape  

CERN Document Server

Disorder on the string theory landscape may significantly affect dynamics of eternal inflation leading to the possibility for some vacua on the landscape to become dynamically preferable over others. We systematically study effects of a generic disorder on the landscape starting by identifying a sector with built-in disorder -- a set of de Sitter vacua corresponding to compactifications of the Type IIB string theory on Calabi-Yau manifolds with a number of warped Klebanov-Strassler throats attached randomly to the bulk part of the Calabi-Yau. Further, we derive continuum limit of the vacuum dynamics equations on the landscape. Using methods of dynamical renormalization group we determine the late time behavior of the probability distribution for an observer to measure a given value of the cosmological constant. We find the diffusion of the probability distribution to significantly slow down in sectors ...

2008-01-01

422

Discrete Element Method for Modeling Penetration  

Science.gov (United States)

... In fact, for dynamic loading, the ultimate compressive strength can be more than doubled (Bischoff and Perry 1991), whereas the ultimate uniaxial ...

2006-07-01

423

Diabetes and risk of incident colorectal cancer in a prospective cohort of women  

UK PubMed Central (United Kingdom)

ObjectiveTo determine whether accounting for the time dynamics of diabetes exposure will change the risk estimates for colorectal cancer.Full Text Available

2010-08-01

424

Design creativity: static or dynamic capability?  

British Library Electronic Table of Contents (United Kingdom)

Purpose - Viewing creativity through the theoretical lens of the resource-based view, the paper attempts to answer a fundamental question: is design creativity a static or dynamic capability? If static, then firms need to acquire personnel who are already creative. If dynamic, then personnel's creative talents should be developed through training. Design/methodology/approach - In an exploratory controlled experiment of 74 design engineers from ten firms, two forms of training emphasizing design creativity as static or dynamic capability were applied. Creative designs developed by the participants were judged by professionals inside each organization. Results were analyzed using structural equation modeling. Findings - The exploratory findings support the notion that design creativity is a ...

2008-01-01

425

DYNAMIC TESTS OF MODEL CONCRETE.  

Science.gov (United States)

... 4 maximum aggregate size. The effects of strain rate (up to 2.5 in./in./sec) on ultimate compressive strength were obtained. ...

1969-11-01

426

Couple stress fluid improve rub-impact rotor-bearing system - Nonlinear dynamic analysis  

British Library Electronic Table of Contents (United Kingdom)

This study performs a dynamic analysis of the rub-impact rotor supported by two couple stress fluid film journal bearings. The strong nonlinear couple stress fluid film force, nonlinear rub-impact force and nonlinear suspension (hard spring) are presented and coupled together in this study. The displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The numerical results show that the dynamic behaviors of the system vary with the dimensionless speed ratios, the dimensionless unbalance parameters and the dimensionless parameter, l*. Inclusive of the periodic, sub-harmonic, quasi-periodic and chaotic motions are found in this analysis. The results of this study contribute to a further understanding of the nonlinear dynamics of a rotor-...

2010-01-01

427

Behavior of particle-filled polymer composite under static and dynamic loading  

British Library Electronic Table of Contents (United Kingdom)

Experimental results of quasi-static and dynamic fracture of particle-filled polymer composite (PFPCM) "ALTUGLAS EI CH25" with a matrix of polymethylmethacrylate (PMMA) are reported in this paper. PMMA matrix is filled with rubber particles, as result a shock-resistant transparent composite is produced. The main task was to investigate experimentally and theoretically the fracture toughness of this composite under static and dynamic loading. A high-rate loading has been created by impulse magnetic field. Analysis of fracture process and its relation with the load parameters and material microstructure have been established. Application of the original testing method enabled determination of fracture toughness at very short loading times and comparison of the results with material dynamic p...

2008-01-01

428

Bacterial chemoreceptors: high-performance signaling in networked arrays  

UK PubMed Central (United Kingdom)

Chemoreceptors are crucial components in the bacterial sensory systems that mediate chemotaxis. Chemotactic responses exhibit exquisite sensitivity, extensive dynamic range and precise adaptation....Full Text Available

2008-01-01

429

Aging in Language Dynamics  

UK PubMed Central (United Kingdom)

Human languages evolve continuously, and a puzzling problem is how to reconcile the apparent robustness of most of the deep linguistic structures we use with the evidence that they undergo possibly...Full Text Available

430

A mathematical model of bone remodeling dynamics for normal bone cell populations and myeloma bone disease  

UK PubMed Central (United Kingdom)

BackgroundMultiple myeloma is a hematologic malignancy associated with the development of a destructive osteolytic bone disease.ResultsMathematical...Full Text Available

431

A New Generic Indexing Technology Michael Freeston CCSE/Alexandria ...  

Science.gov (United States)

freeston@alexandria.sdc.ucsb.edu tel: 805-893-8589 fax: 805-893-3045. _. ,' .;_. .'_. Abstract. There has been no fundamental change in the dynamic indexing ...

432

120-MM Gun Tube Erosion Including Surface Chemistry ...  

Science.gov (United States)

... with dynamic gridding capability to account for material ablation, as well as the addition of energy sources and heat transfer augmentation due to ...

1997-10-01

433

Hydration of swelling clay and bacteria interaction. An experimental in situ reaction study; Hydratation des argiles gonflantes et influence des bacteries. Etude experimentale de reaction in situ  

Energy Technology Data Exchange (ETDEWEB)

This study reports on the physical-chemical behaviour of swelling di-octahedral clays (smectites) and their interaction with aqueous solutions and bacteria (Shewanella putrefaciens). Experimental results are presented for compacted clays, hydrated under confined volume conditions, using a new type of reaction-cell (the 'wet-cell' of Warr and Hoffman, 2004) that was designed for in situ X-ray diffraction (XRD) measurement. For comparison, dispersed clay systems were studied using standard batch solutions subjected to varying degrees of agitation. The combination of time-dependent in situ XRD measurements with gravimetric measurements and calculated diffraction patterns using the CALCMIX software (Plancon and Drits, 1999) allowed to successful quantification of the dynamics of water uptake and storage. This analytical procedure combined with published water vapour adsorption data enabled determination of the abundance of structured water layers, ...

2008-01-15

434

Detection of high-frequency radiation sources during the 2004 Parkfield earthquake by a matched filter analysis  

Science.gov (United States)

Introduction Uchide and Ide [SSA Spring Meeting, 2009] proposed a new framework for studying the scaling and overall nature of earthquake rupture growth in terms of cumulative moment functions. For better understanding of rupture growth processes, spatiotemporally local processes are also important. The nature of high-frequency (HF) radiation has been investigated for some time, but its role in the earthquake rupture process is still unclear. A wavelet analysis reveals that the HF radiation (e.g., 4 - 32 Hz) of the 2004 Parkfield earthquake is peaky, which implies that the sources of the HF radiation are isolated in space and time. We experiment with applying a matched filter analysis using small template events occurring near the target event rupture area to test whether it can reveal the HF radiation sources for a regular large earthquake. Method We design a matched filter for multiple components and stations. Shelly et al. [2007] attempted identifying low-frequency earthquakes (LFE) ...

2009-12-01

435

Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration  

Energy Technology Data Exchange (ETDEWEB)

Waveform correlation detectors compare a signal template with successive windows of a continuous data stream and report a detection when the correlation coefficient, or some comparable detection statistic, exceeds a specified threshold. Since correlation detectors exploit the fine structure of the full waveform, they are exquisitely sensitive when compared to power (STA/LTA) detectors. The drawback of correlation detectors is that they require complete knowledge of the signal to be detected, which limits such methods to instances of seismicity in which a very similar signal has already been observed by every station used. Such instances include earthquake swarms, aftershock sequences, repeating industrial seismicity, and many other forms of controlled explosions. The reduction in the detection threshold is even greater when the techniques are applied to arrays since stacking can be performed on the individual channel correlation traces to achieve significant array ...

2009-07-23

436

To study the role of dynamic magnetic resonance imaging in assessing the femoral head vascularity in intracapsular femoral neck fractures  

Energy Technology Data Exchange (ETDEWEB)

Intracapsular femoral neck fractures remain unsolved fractures even after improvement in techniques of diagnosis and internal fixation. Individuals who sustain displaced femoral neck fractures are at high risk of developing avascular necrosis and non-union. Although several methods for predicting the viability of femoral head have been reported, they are not effective or widely used because of unreliability, potential complications and technical difficulties. Dynamic MRI was introduced in the recent past as a simple, non-invasive technique to predict the femoral head viability after the femoral neck fractures. In this study role of dynamic MRI was studied in 30 patients with 31 intracapsular femoral neck fractures. Fractures were divided in to three types according to dynamic curve patterns on MRI evaluation and were followed up for 6 months to 2 years to observe the final outcome. Sensitivity, Specificity and the Accuracy ...

2010-09-15

437

To study the role of dynamic magnetic resonance imaging in assessing the femoral head vascularity in intracapsular femoral neck fractures  

International Nuclear Information System (INIS)

Intracapsular femoral neck fractures remain unsolved fractures even after improvement in techniques of diagnosis and internal fixation. Individuals who sustain displaced femoral neck fractures are at high risk of developing avascular necrosis and non-union. Although several methods for predicting the viability of femoral head have been reported, they are not effective or widely used because of unreliability, potential complications and technical difficulties. Dynamic MRI was introduced in the recent past as a simple, non-invasive technique to predict the femoral head viability after the femoral neck fractures. In this study role of dynamic MRI was studied in 30 patients with 31 intracapsular femoral neck fractures. Fractures were divided in to three types according to dynamic curve patterns on MRI evaluation and were followed up for 6 months to 2 years to observe the final outcome. Sensitivity, Specificity and the Accuracy ...

2010-09-01

438

Tragedy and delight: the ethics of decelerated ageing  

UK PubMed Central (United Kingdom)

Biogerontology is sometimes viewed as similar to other forms of biomedical research in that it seeks to understand and treat a pathological process. Yet the prospect of treating ageing is extraordinary...Full Text Available

2011-01-12

439

Test Planning Guide for ASF Facilities  

Science.gov (United States)

15 to 75% of the gun barrel diameter. Similarly, model masses typically vary from 0.01 to 100 .... taining acceptable levels of gun barrel erosion. The ...

440

Summaries of Competitive Food Defense Research Reports, 2005  

Science.gov (United States)

... The least effective disinfectant was CTACl, which is a quaternary ammonium surfactant similar to those used in common household disinfectants. ...

441

Self-similarity in NMR Spectra: An Application in Assessing the Level of Cysteine  

UK PubMed Central (United Kingdom)

High resolution of NMR spectroscopic data of biosamples are a rich source of information on the metabolic response to physiological variation or pathological events. There are many advantages...Full Text Available

2010-01-01

442

Seismic Stability Evaluation of Alben Barkley Lock and Dam ...  

Science.gov (United States)

... similar to the S-wave tests except that exploding bridgewire detonators (EBW's) were used as the P-wave source. Crosshole ...

1989-03-01

443

On the ideal gas of tachyons  

International Nuclear Information System (INIS)

The properties of the ideal gas of classical (nonquantum) tachyons are considered. Starting from the definition of thermodynamic functions for this system, it may be found that tachyons and bradyons gases are similar. (AA).

444

New Image - ONLY - Scan to PDF - NASA Technical Reports Server  

Science.gov (United States)

Aluminum electrolytic capacitors are presently not allowed ..... specified for commercial aluminum electrolytic capacitors of similar rating. ...

445

N88-21509 - NASA Technical Report Server (NTRS)  

Science.gov (United States)

problem similar to the Stefan problem in heat conduction [19]. ..... as the Stefan problem. Although the Stefan problem and the creep rupture ...

446

Method for the reduction of image content redundancy in large image databases  

Energy Technology Data Exchange (ETDEWEB)

A method of increasing information content for content-based image retrieval (CBIR) systems includes the steps of providing a CBIR database, the database having an index for a plurality of stored digital images using a plurality of feature vectors, the feature vectors corresponding to distinct descriptive characteristics of the images. A visual similarity parameter value is calculated based on a degree of visual similarity between features vectors of an incoming image being considered for entry into the database and feature vectors associated with a most similar of the stored images. Based on said visual similarity parameter value it is determined whether to store or how long to store the feature vectors associated with the incoming image in the database.

2010-03-02

447

MTF ' MISSISSIPPI SOUND REMOTE SENSING STUDY I 19 SEPTEMBER 1972  

Science.gov (United States)

metric temperatures has been prepared showing the surface water temper- ... occasion, gray levels show different densities for similar water temper- ...

448

Lichen striatus - close-up (image)  

Science.gov (United States)

Lichen striatus begins similarly to lichen planus, with small bumps (papules), but over a period of days expands to form a long streak or band of affected ...

449

In vitro activity and human pharmacokinetics of teicoplanin.  

UK PubMed Central (United Kingdom)

The in vitro activity of teicoplanin, a new antibiotic related to vancomycin, was determined against 456 gram-positive cocci. The activity of teicoplanin in comparison with that of vancomycin was similar...Full Text Available

1984-12-01

450

Functional Consequences of Sarcopenia and Dynapenia in the Elderly  

UK PubMed Central (United Kingdom)

Purpose of reviewThe economic burden due to the sequela of sarcopenia (muscle wasting in the elderly) are staggering and rank similarly to the costs...Full Text Available

2010-05-01

451

Foveo-macular retinitis, solar retinopathy, and trauma.  

UK PubMed Central (United Kingdom)

Three patients are described with foveal lesions resembling minute holes following trauma. The similarity of the lesions to foveomacular retinitis and solar retinopathy suggests that all these conditions...Full Text Available

1978-08-01

452

Evaluation of Commercial Magnetic Descalers.  

Science.gov (United States)

With the increased costs of maintaining boilers and chillers entrepreneurs around the country have offered magnetic and similar devices to facilities as viable alternatives to their maintenance program. This report gives a brief history of some of the pre...

1984-01-01

453

Entropy, similarity measure of interval-valued intuitionistic fuzzy sets and their applications  

British Library Electronic Table of Contents (United Kingdom)

In this paper we propose an entropy measure for interval-valued intuitionistic fuzzy sets, which generalizes three entropy measures defined independently by Szmidt, Wang and Huang, for intuitionistic fuzzy sets. We also give an approach to construct similarity measures using entropy measures for interval-valued intuitionistic fuzzy sets. In particular, the proposed entropy measure for interval-valued intuitionistic fuzzy sets can yield a similarity measure. Several illustrative examples are given to demonstrate the practicality and effectiveness of the proposed formulas. We apply the similarity measure to solve problems on pattern recognitions, multi-criteria fuzzy decision making and medical diagnosis.

2011-01-01

454

Effective Software Reuse in an Embedded Realtime System  

Science.gov (United States)

... Many of the functions required of the SMB are JANAP-128,-JINTACCS). The SMB can also get similar to other military message processing systems ...

1993-02-01

455

Effect of Smoking Scenes in Films on Immediate Smoking  

UK PubMed Central (United Kingdom)

BackgroundThe National Cancer Institute has concluded that exposure to smoking in movies causes adolescent smoking and there are similar results for young adults.Full Text Available

2010-04-01

456

Defense Horizons. Number 18, October 2002. High-Energy ...  

Science.gov (United States)

... assets, particularly against ballistic missiles with weapons of mass ... more con- ventional missile and gun weapon systems. ... Similarly, space-based ...

2002-10-01

457

DNA synthesis inhibition in mammalian cells as a test for mutagenic carcinogens  

Science.gov (United States)

Current models of DNA repair of biological damage are reviewed correlating the similarity between carcinogenesis and mutagenesis theories. (PCS)

1979-01-01

458

Combining Genetics and Population History in the Study of Ethnic Diversity in the People's Republic of China  

Science.gov (United States)

... some Central Asian populations (Zerjal et al. 2002). Haplogroup W has a similar Middle Eastern origin, and again ... ...

459

Benchmarking Declarative Approximate Selection Predicates  

CERN Document Server

Declarative data quality has been an active research topic. The fundamental principle behind a declarative approach to data quality is the use of declarative statements to realize data quality primitives on top of any relational data source. A primary advantage of such an approach is the ease of use and integration with existing applications. Several similarity predicates have been proposed in the past for common quality primitives (approximate selections, joins, etc.) and have been fully expressed using declarative SQL statements. In this thesis, new similarity predicates are proposed along with their declarative realization, based on notions of probabilistic information retrieval. Then, full declarative specifications of previously proposed similarity predicates in the literature are presented, grouped into classes according to their primary characteristics. Finally, a thorough performance and accuracy study comparing a ...

2009-01-01

460

Bandwidth Allocation to Interactive Users in DBS-Based ...  

Science.gov (United States)

... end-to-end TCP connection from the hybrid terminal ... peculiar to self-similar stochastic processes, ... Queue First (MDQF) schemes are employed at the ...

2011-05-13

461

Alpha/Beta Heat Treatment of a Titanium Alloy with a Non ...  

Science.gov (United States)

... transformed at 705°C. The cooling rate and temperature dependence of matrix decomposition for Ti6242 was thus similar to that for Ti64 x [9]. ...

2006-08-01

462

APOD: July 10, 1998 - Interacting Galaxies  

Science.gov (United States)

believe the system is similar to the face-on spiral and companion known as M51, the Whirlpool Galaxy. Tomorrow's picture: Sleeping Beauty < Archive | Index | Search | Calendar |...

2011-10-07

463

APOD: 2008 November 27 - Galaxies in the River  

Science.gov (United States)

to be similar to the system of face-on spiral and small companion known as M51, the Whirlpool Galaxy. Tomorrow's picture: Beta Pic < | Archive | Index | Search | Calendar | RSS |...

2011-10-07

464

A New Tool for Accurately Measuring the Inside Diameter of a ...  

Science.gov (United States)

Page 1. AD-769 272 A NEW TOOL FOR ACCURATELY MEASURING THE INSIDE DIAMETER OF A GUN BARREL, LONG TUBE, OR SIMILAR ...

1973-08-29

465

A NEW SPECIES OF WOLF SNAKE (SERPENTES: COLUBRIDAE: LYCODON) FROM THE CARDAMOM MOUNTAINS, SOUTHWESTERN CAMBODIA  

Science.gov (United States)

... owing to its superficial similarity to the elapid Bungarus candidus. The latter has also been documented in ... ...

466

A Methodology for Developing Timing Constraints for the ...  

Science.gov (United States)

... pursued for a similar space-based system, ... determine the most capable and opportunistic weapon ... Haim Baruch, Battle Management, AIAA, 2000, p ...

2003-12-01

467

A Comparison of Chinese and American Indian (Chumash) Medicine  

UK PubMed Central (United Kingdom)

Chinese and Chumash traditional medical approaches are similar in terms of disease causation, use of acupuncture or healing touch, plants, spiritual and philosophical approaches. This article provides...Full Text Available

2010-06-01

468

8 - NASA Technical Report Server (NTRS)  

Science.gov (United States)

feature similar to the face detection in Intel's OpenCV library, implement it in Matlab code, and test the performance of the new ROI detector against the ...

469

Thermo-hydraulic design of Chinese helium cooled solid breeder blanket for ITER-TBM  

International Nuclear Information System (INIS)

To further optimize thermo-hydraulic capability of HCSB-TBM, two different thermo-hydraulic schemes would be proposed and investigated by relevant calculating and simulating of thermo-dynamics in normal and peak heat flux condition. With computational fluid dynamics (CFD) code FLUENT, the actual temperature distribution of key components of HCSB-TBM is simulated. (authors)

2009-06-01

470

The Montreal protocol: A dynamic agreement for protecting the ozone layer  

Energy Technology Data Exchange (ETDEWEB)

The Montreal Protocol provides the international community with an effective equitable and dynamic mechanism for protecting the ozone layer. The paper uses the Protocol's negotiating history to describe how and why agreement on a particular issue was reached and provides an in-depth analysis of the Protocol's most innovative provisions. The paper discusses international implementation of the Protocol. It concludes with a brief description of recent developments leading up to the Protocol's possible modification in June 1990. (14 refs.).

1990-04-01

471

Test and simulation of dynamic phase compensation from Mita-Teknik A/S  

Energy Technology Data Exchange (ETDEWEB)

This report describes the test of a dynamic phase compensation unit for a wind turbine with directly connected induction generators. The compensation unit is based on thyristor switched capacitors, where conventional wind turbine compensations use mechanical contactors to switch the capacitors. The influence on power quality analysed, and influence on component lifetime is discussed. Besides, simulation models in Matlab/Simulink are presented, including a flicker meter model. (au)

2004-03-01

472

Study on dynamic compaction of a buffer material mixed with bentonite for H.L.W. final disposal  

International Nuclear Information System (INIS)

In-situ compaction method is an alternative technology for the construction of a buffer at HLW final disposal. Understanding of the compaction characteristics of the proposed material is important for this method of construction. In this report, paying attention to the relation between compaction energy and the achieved maximum dry density, dynamic compaction characteristic of bentonite and silica sand mixture material is examined. (author)

2004-06-01

473

Simulation of laser melting and evaporation of superconducting ceramics  

Energy Technology Data Exchange (ETDEWEB)

The peculiarities of pulsed laser melting and evaporation of the superconducting ceramics are analyzed by means of numerical simulation. The appearance of the overheated metastable states in solid and liquid phases is shown as a result of the phase front dynamics and volume nature of laser energy release. A method of dynamic adaptation for the multifront Stefan problem is proposed.

1994-11-01

474

Pile foundations for offshore structures  

Energy Technology Data Exchange (ETDEWEB)

Pile foundations are extensively used to support off-shore and on-shore structures. Under dynamic loads, the behavior of single pile is well understood. However the soil-pile-soil interaction studies are confusing, on which account the analyses do not necessarily predict response of the systems which may match satisfactorily with the performances. In this paper, the nature of dynamic loads is described, and solutions for soil-pile and pile-soil-pile interaction solutions by several authors are presented and a critical evaluation is made.

1994-12-31

475

Phase transitions in multiplicative competitive processes  

Science.gov (United States)

We introduce a discrete multiplicative process as a generic model of competition. Players with different abilities successively join the game and compete for finite resources. Emergence of dominant players and evolutionary development occur as a phase transition. The competitive dynamics underlying this transition is understood from a formal analogy to statistical mechanics. The theory is applicable to bacterial competition, predicting novel population dynamics near criticality.

2005-07-01

476

Observational constraints in scalar tensor theory with tachyonic potential  

CERN Document Server

We study the dynamics of the scalar tensor cosmological model in the presence of tachyon field. In an alternative approach, in two exponential and power law form of the scalar field functions in the model, field equations are solved by simultaneously best fitting the model parameters with the most recent observational data. This approach gives us an observationally verified interpretation of the dynamics of the universe. We then discuss the best fitted of equation of state parameter, the statefinder parameters and the reconstructed scalar field in the model.

2011-01-01

477

Neutralization of negative ion beams by a gas dynamic laser  

Energy Technology Data Exchange (ETDEWEB)

The possibility of applying the near infrared gas dynamic lasers (GDL) for neutralization of negative ion beams is examined. A criterion of neutralization is suggested. The use of the criterion makes it possible to select an optically active medium for a negative ion neutralization. To demonstrate the method media containing hydrohalogens as imitating molecules are taken. ((orig.))

1994-11-01

478

Molecular dynamics simulation of nanoctrystalline nickel: structure and mechanical properties  

Energy Technology Data Exchange (ETDEWEB)

Molecular dynamics computer simulations of a dense nanocrystalline Nickel sample are performed on the parallel Cray T3 (EPFL-Lausanne). The sample contains 50 grains with an average size of 3 nm. By perturbing the relaxed configuration elastic and plastic properties are studied. (author) 1 fig., 1 ref.

1996-10-01

479

Helicoidal instability of a scroll vortex in three-dimensional reaction-diffusion systems  

International Nuclear Information System (INIS)

We study the dynamics of scroll vortices in excitable reaction-diffusion systems analytically and numerically. We demonstrate that intrinsic three-dimensional instability of a straight scroll leads to the formation of helicoidal structures. This behavior originates from the competition between the scroll curvature and unstable core dynamics. We show that the obtained instability persists even beyond the meander core instability of the two-dimensional spiral wave. copyright 1998 The American Physical Society.

1998-10-01

480

Genome-wide analysis reveals rapid and dynamic changes in miRNA and siRNA sequence and expression during ovule and fiber development in allotetraploid cotton (Gossypium hirsutum L.)  

UK PubMed Central (United Kingdom)

BackgroundCotton fiber development undergoes rapid and dynamic changes in a single cell type, from fiber initiation, elongation, primary and secondary wall biosynthesis, to fiber...Full Text Available

2009-01-01

481

Efficiency of selective IR multiphoton dissociation of molecules in a pulsed gas-dynamic flow interacting with a solid surface  

International Nuclear Information System (INIS)

Isotopically selective IR multiphoton dissociation of molecules (SF_6, CF_3I) in a pulsed gas-dynamic flow interacting with a solid surface was studied for the first time. A noticeable (severalfold) increase in the yield of products (compared to excitation of molecules in an unperturbed flow) without a substantial decrease in the selectivity of the process was observed. Possible reasons for the effect are discussed. (laser applications and other topics in quantum electronics)

2000-08-31

482

Dynamics of electrooptic bistable devices with delayed feedback  

Science.gov (United States)

The dynamic behavior of electrooptic bistable devices with delayed feedback is investigated theoretically and experimentally. The operation principle of the system is analyzed by the method of iterated maps. Stable, bistable, periodic, higher periodic, and chaotic solutions are discussed and realized experimentally by using an integrated Mach-Zehnder interferometer on LiNbO3 as a basic nonlinear element. Taking into account the periodic modulator characteristic, the application of this device as a simple and fast bistable and monostable multivibrator is demonstrated. In addition, the synchronization properties of the astable multivibrator are investigated.

1982-12-01

483

Dynamic performance testing of control valves  

International Nuclear Information System (INIS)

Response of control valves plays an important role in the dynamics of the flow system as a whole. Knowledge of its transfer function would facilitate analysis of the behaviour of the system. This paper presents the application of Levy's complex curve fitting method for determination of the transfer function of control valves used in Liquid Zone Control System of 540 MWe PHWR. (author)

2005-02-01

484

Dynamic models of staged gasification processes. Documentation of gasification simulator; Dynamiske modeller a f trinopdelte forgasningsprocesser. Dokumentation til forgasser simulator  

Energy Technology Data Exchange (ETDEWEB)

In connection with the ERP project 'Dynamic modelling of staged gasification processes' a gasification simulator has been constructed. The simulator consists of: a mathematical model of the gasification process developed at Technical University of Denmark, a user interface programme, IGSS, and a communication interface between the two programmes. (BA)

2005-02-15

485

Dynamic enhanced MRI of the subacromial bursa: correlation with arthroscopic and histological findings  

Energy Technology Data Exchange (ETDEWEB)

Objective: To assess dynamic MRI with Gd-DTPA enhancement for evaluating inflammatory changes in the subacromial bursa. Design and patients: We detected the signal intensity changes in dynamic MRI of the subacromial bursa, and confirmed these macroscopically by arthroscopy and histologically. The signal intensity was measured using built-in software, and the enhancement ratio (E ratio) was calculated from dynamic MR images. In addition, as a parameter of the rate of the increase in the signal intensity from 0 to 80 s, the mean increase per second in the E ratio was obtained as the coefficient of enhancement (CE). The correlation was studied of the E ratio and CE with the arthroscopic findings (redness, villous formation, thickening and adhesion), and of the E ratio and CE with the histological findings (capillary proliferation, papillary hyperplasia, fibrosis and inflammatory cell infiltration) of the subacromial bursa. Of ...

2003-09-01

486

Dynamic Deformation and Recovery Response of Red Blood Cells to a Cyclically Reversing Shear Flow: Effects of Frequency of Cyclically Reversing Shear Flow and Shear Stress Level  

UK PubMed Central (United Kingdom)

Dynamic deformation and recovery responses of red blood cells (RBCs) to a cyclically reversing shear flow generated in a 30-μm clearance, with the peak shear stress of 53, 108,...Full Text Available

2006-09-01

487

Dimension reduction in fluid dynamics equations  

British Library Electronic Table of Contents (United Kingdom)

A method for transforming the Euler and Navier-Stokes equations and a complete system of fluid dynamics equations in three dimensions to a closed system on any moving surface is proposed. As a result, for an arbitrary geometric configuration, the dimension of the equations is reduced by one, which makes them convenient for numerical simulation. The general principles of the method are described, and verifying examples are presented.

2011-01-01

488

Comparing two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the hypofractionated treatment of high-risk prostate cancer  

UK PubMed Central (United Kingdom)

BackgroundTo compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated...Full Text Available

489

Business Cycle and Conserved Quantity in Economics  

CERN Document Server

We propose a dynamical model for business cycle based on an optimal DI model. In the model there exists a conserved quantity, which corresponds to the total energy in a dynamical system. We found that the business cycle with the period 6 or 7 years is nicely reproduced, since the model predicts a periodic motion in the conservative system.

2008-01-01

490

Analysis of a manipulator in relation to collision between a link and an object  

British Library Electronic Table of Contents (United Kingdom)

In this article, equations of motion of a manipulator are derived after consideration of the characteristics of the driving source. By considering a collision between a link and an object, and considering the active motion to absorb the kinetic energy of the object, the trajectories for saving energy are calculated by the iterative dynamic programming (IDP) method. The dynamic characteristics of manipulator control based on the trajectory for saving energy are also analyzed theoretically and investigated experimentally.

2011-01-01

491

Ab initio molecular dynamics with born-oppenheimer and extended lagrangian methods using atom centered basis functions  

Energy Technology Data Exchange (ETDEWEB)

In ab initio molecular dynamics, whenever information about the potential energy surface is needed for integrating the equations of motion, it is computed 'on the fly' using electronic structure calculations. For Born-Oppenheimer methods, the electronic structure calculations are converged, whereas in the extended Lagrangian approach the electronic structure is propagated along with the nuclei. Some recent advances for both approaches are discussed.

2003-06-01

492

A two-frequency Wiggler for a better control of a free-electron-laser dynamics  

Energy Technology Data Exchange (ETDEWEB)

In the paper is studied the physics of a free electron laser (FEL) based on a two-frequency undulator (TFU) which induces large non linear effects, especially on the spectral dynamics. These effects are analyzed in an extended formalism where the spontaneous emission, the low-gain regime and the strong-field saturation regime are studied. Numerical simulations show that the optimized TFU generates a laser field having both a large extraction efficiency and a narrow spectrum.

1991-12-31

493

A review of mesospheric dynamics and chemistry  

Energy Technology Data Exchange (ETDEWEB)

Advances made in understanding the chemistry and dynamics of the atmosphere in the approximate altitude range of 50 to 90 km are addressed. Attention is given to mesospheric structure and seasonal variations, gravity waves and gravity wave saturation, the effects of gravity waves on thermal, momentum and constituent fluxes, and the effect of gravity waves on airglow emissions. A review of research on tides and planetary waves and their effects on the mesosphere are presented as well as discussions on ozone hydroxyl, water vapor, and noctilucent cloud research. 217 refs.

1991-01-01

494

A comparison of nutrient dynamics in forest ecosystems along with the Warmth Index Gradient  

Energy Technology Data Exchange (ETDEWEB)

Nutrient elements contained in litter fall flux, that of uptake flux and turnover rate had generally tended to increase with the increase in the Warmth Index, while the amount of nutrient in the A[sub 0] horizon and nutrient use efficiency did not. However, it is suggested that topographic and climatic aridity, and the amount of available and exchangeable phosphorus, calcium and magnesium greatly affect the nutrient dynamics in a each forest ecosystem as the Warmth Index increases. (J.P.N.).

1993-01-01

495

Stiff Stability of the Hydrogen atom in dissipative Fokker electrodynamics  

CERN Document Server

We introduce an ad-hoc electrodynamics with advanced and retarded Lienard-Wiechert interactions plus the dissipative Lorentz-Dirac self-interaction force. We study the covariant dynamical system of the electromagnetic two-body problem, i.e., the hydrogen atom. We perform the linear stability analysis of circular orbits for oscillations perpendicular to the orbital plane. In particular we study the normal modes of the linearized dynamics that have an arbitrarily large imaginary eigenvalue. These large eigenvalues are fast frequencies that introduce a fast (stiff) timescale into the dynamics. As an application, we study the phenomenon of resonant dissipation, i.e., a motion where both particles recoil together in a drifting circular orbit (a bound state), while the atom dissipates center-of-mass energy only. This balancing of the stiff dynamics is established by the existence of a quartic resonant ...

2005-01-01

496

Homoclinic chaos in the dynamics of a general Bianchi type-IX model  

International Nuclear Information System (INIS)

The dynamics of a general Bianchi type-IX model with three scale factors is examined. The matter content of the model is assumed to be comoving dust plus a positive cosmological constant. The model presents a critical point of saddle-center-center type in the finite region of phase space. This critical point engenders in the phase space dynamics the topology of stable and unstable four dimensional tubes RxS"3, where R is a saddle direction and S"3 is the manifold of unstable periodic orbits in the center-center sector. A general characteristic of the dynamical flow is an oscillatory mode about orbits of an invariant plane of the dynamics which contains the critical point and a Friedmann-Robertson-Walker (FRW) singularity. We show that a pair of tubes (one stable, one unstable) emerging from the neighborhood of the critical point towards the FRW singularity have homoclinic transversal crossings. The ...

2002-04-15