Simplified Theory of Plastic Zones for cyclic loading and multilinear hardening

International Nuclear Information System (INIS)

Hübel, Hartwig

2015-01-01

The Simplified Theory of Plastic Zones (STPZ) is a direct method based on Zarka's method, primarily developed to estimate post-shakedown quantities of structures under cyclic loading, avoiding incremental analyses through a load histogram. In a different paper the STPZ has previously been shown to provide excellent estimates of the elastic–plastic strain ranges in the state of plastic shakedown as required for fatigue analyses. In the present paper, it is described how the STPZ can be used to predict the strains accumulated through a number of loading cycles due to a ratcheting mechanism, until either elastic or plastic shakedown is achieved, so that strain limits can be satisfied. Thus, a consistent means of estimating both, strain ranges and accumulated strains is provided for structural integrity assessment as required by pressure vessel codes. The computational costs involved typically consist of few linear elastic analyses and some local calculations. Multilinear kinematic hardening and temperature dependent yield stresses are accounted for. The quality of the results and the computational burden involved are demonstrated through four examples. - Highlights: • A method is provided to estimate accumulated elastic–plastic strains. • A consistent method is provided to estimate elastic–plastic strain ranges. • Effect of multilinear kinematic hardening is captured. • Temperature dependent material properties are accounted for. • Few linear elastic analyses required

Dynamic rupture models of subduction zone earthquakes with off-fault plasticity

Science.gov (United States)

Wollherr, S.; van Zelst, I.; Gabriel, A. A.; van Dinther, Y.; Madden, E. H.; Ulrich, T.

2017-12-01

Modeling tsunami-genesis based on purely elastic seafloor displacement typically underpredicts tsunami sizes. Dynamic rupture simulations allow to analyse whether plastic energy dissipation is a missing rheological component by capturing the complex interplay of the rupture front, emitted seismic waves and the free surface in the accretionary prism. Strike-slip models with off-fault plasticity suggest decreasing rupture speed and extensive plastic yielding mainly at shallow depths. For simplified subduction geometries inelastic deformation on the verge of Coulomb failure may enhance vertical displacement, which in turn favors the generation of large tsunamis (Ma, 2012). However, constraining appropriate initial conditions in terms of fault geometry, initial fault stress and strength remains challenging. Here, we present dynamic rupture models of subduction zones constrained by long-term seismo-thermo-mechanical modeling (STM) without any a priori assumption of regions of failure. The STM model provides self-consistent slab geometries, as well as stress and strength initial conditions which evolve in response to tectonic stresses, temperature, gravity, plasticity and pressure (van Dinther et al. 2013). Coseismic slip and coupled seismic wave propagation is modelled using the software package SeisSol (www.seissol.org), suited for complex fault zone structures and topography/bathymetry. SeisSol allows for local time-stepping, which drastically reduces the time-to-solution (Uphoff et al., 2017). This is particularly important in large-scale scenarios resolving small-scale features, such as the shallow angle between the megathrust fault and the free surface. Our dynamic rupture model uses a Drucker-Prager plastic yield criterion and accounts for thermal pressurization around the fault mimicking the effect of pore pressure changes due to frictional heating. We first analyze the influence of this rheology on rupture dynamics and tsunamigenic properties, i.e. seafloor

Finite element analysis of cylindrical indentation for determining plastic properties of materials in small volumes

International Nuclear Information System (INIS)

Lu, Y Charles; Kurapati, Siva N V R K; Yang Fuqian

2008-01-01

The cylindrical indentation is analysed, using the finite element method, for determining the plastic properties of elastic-plastic materials and the effect of strain hardening. The results are compared with those obtained from spherical indentation, the commonly used technique for measuring plastic properties of materials in small volumes. The analysis shows that the deformation under a cylindrical indenter quickly reaches a fully plastic state and that the size (diameter) of the plastic zone remains constant during further indentation. The indentation load is proportional to the indentation depth at large indentation depth, from which the indentation pressure P m at the onset of yielding can be readily extrapolated. The analysis of cylindrical indentation suggests that it does not need parameters such as impression radius (a) and contact stiffness (S) for determining the plastic behaviour of materials. Thus, the cylindrical indentation can suppress the uncertainties in measuring material properties

Performance study of the simplified theory of plastic zones and the Twice-Yield method for the fatigue check

International Nuclear Information System (INIS)

Hübel, Hartwig; Willuweit, Adrian; Rudolph, Jürgen; Ziegler, Rainer; Lang, Hermann; Rother, Klemens; Deller, Simon

2014-01-01

As elastic–plastic fatigue analyses are still time consuming the simplified elastic–plastic analysis (e.g. ASME Section III, NB 3228.5, the French RCC-M code, paragraphs B 3234.3, B 3234.5 and B3234.6 and the German KTA rule 3201.2, paragraph 7.8.4) is often applied. Besides linearly elastic analyses and factorial plasticity correction (K e factors) direct methods are an option. In fact, calculation effort and accuracy of results are growing in the following graded scheme: a) linearly elastic analysis along with K e correction, b) direct methods for the determination of stabilized elastic–plastic strain ranges and c) incremental elastic–plastic methods for the determination of stabilized elastic–plastic strain ranges. The paper concentrates on option b) by substantiating the practical applicability of the simplified theory of plastic zones STPZ (based on Zarka's method) and – for comparison – the established Twice-Yield method. The Twice-Yield method is explicitly addressed in ASME Code, Section VIII, Div. 2. Application relevant aspects are particularly addressed. Furthermore, the applicability of the STPZ for arbitrary load time histories in connection with an appropriate cycle counting method is discussed. Note, that the STPZ is applicable both for the determination of (fatigue relevant) elastic–plastic strain ranges and (ratcheting relevant) locally accumulated strains. This paper concentrates on the performance of the method in terms of the determination of elastic–plastic strain ranges and fatigue usage factors. The additional performance in terms of locally accumulated strains and ratcheting will be discussed in a future publication. - Highlights: • Simplified elastic–plastic fatigue analyses. • Simplified theory of plastic zones. • Thermal cyclic loading. • Twice-Yield method. • Practical application examples

ELASTIC-PLASTIC AND RESIDUAL STRESS ANALYSIS OF AN ALUMINUM DISC UNDER INTERNAL PRESSURES

Directory of Open Access Journals (Sweden)

Numan Behlül BEKTAŞ

2004-02-01

Full Text Available This paper deals with elastic-plastic stress analysis of a thin aluminum disc under internal pressures. An analytical solution is performed for satisfying elastic-plastic stress-strain relations and boundary conditions for small plastic deformations. The Von-Mises Criterion is used as a yield criterion, and elastic perfectly plastic material is assumed. Elastic-plastic and residual stress distributions are obtained from inner radius to outer radius, and they are presented in tables and figures. All radial stress components, ?r, are compressive, and they are highest at the inner radius. All tangential stress components, ??, are tensile, and they are highest where the plastic deformation begins. Magnitude of the tangential residual stresses is higher than those the radial residual stresses.

Limit load and fully plastic stress analysis for circular notched plates and bars using fully plastic analysis

International Nuclear Information System (INIS)

Oh, Chang Kyun; Myung, Man Sik; Kim, Yun Jae; Park, Jin Moo

2005-01-01

For the last four decades, tension test of notched bars has been performed to investigate the effect of stress triaxiality on ductile fracture. To quantify the effect of the notch radius on stress triaxiality, the Bridgman equation is typically used. However, recent works based on detailed finite element analysis have shown that the Bridgman equation is not correct, possibly due to his assumption that strain is constant in the necked ligament. Up to present, no systematic work has been performed on fully plastic stress fields for notched bars in tension. This paper presents fully plastic results for tension of notched bars and plates in plane strain, via finite element limit analysis. The notch radius is systematically varied, covering both un-cracked and cracked cases. Comparison of plastic limit loads with existing solutions shows that existing solutions are accurate for notched plates, but not for notched bars. Accordingly new limit load solutions are given for notched bars. Variations of stress triaxiality with the notch radius and depth are also given, which again indicates that the Bridgman solution for notched bars is not correct and inaccuracy depends on the notch radius and depth

Investigation of plastic zones near SCC tips in a pipeline after hydrostatic testing

International Nuclear Information System (INIS)

Li Jian; Elboujdaini, M.; Gao, M.; Revie, R.W.

2008-01-01

Stress corrosion cracking (SCC) is an important failure mechanism for oil and gas pipelines. In the past, hydrostatic testing has been frequently used to assess and mitigate stress corrosion cracking. It is commonly agreed that an effective hydrostatic test not only eliminates critical crack-like flaws, but also blunts the sub-critical crack tip thereby suppressing further SCC propagation. However, little study has been done on the plastic deformation that results from the high stress intensity at the crack tip due to hydrostatic testing pressure and its possible role in subsequent SCC propagation. In this study, microstructural details were examined of an API 5L X52 SCC-containing pipe removed from field service. Plastic deformation generated by the hydrostatic testing pressure was revealed by using high-resolution imaging of a focused ion beam (FIB) microscope. The existence of the microscopic plastic zones around some crack tips suggests that caution should be taken when setting up pipeline hydrostatic tests

Investigation of plastic zones near SCC tips in a pipeline after hydrostatic testing

Energy Technology Data Exchange (ETDEWEB)

Li Jian [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)], E-mail: jili@nrcan.gc.ca; Elboujdaini, M [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada); Gao, M [Blade Energy Partners, 16225 Park Ten Place, Suite 450, Houston, TX 77084 (United States); Revie, R W [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)

2008-07-15

Stress corrosion cracking (SCC) is an important failure mechanism for oil and gas pipelines. In the past, hydrostatic testing has been frequently used to assess and mitigate stress corrosion cracking. It is commonly agreed that an effective hydrostatic test not only eliminates critical crack-like flaws, but also blunts the sub-critical crack tip thereby suppressing further SCC propagation. However, little study has been done on the plastic deformation that results from the high stress intensity at the crack tip due to hydrostatic testing pressure and its possible role in subsequent SCC propagation. In this study, microstructural details were examined of an API 5L X52 SCC-containing pipe removed from field service. Plastic deformation generated by the hydrostatic testing pressure was revealed by using high-resolution imaging of a focused ion beam (FIB) microscope. The existence of the microscopic plastic zones around some crack tips suggests that caution should be taken when setting up pipeline hydrostatic tests.

Plastic buckling of cylindrical shells

International Nuclear Information System (INIS)

Bandyopadhyay, K.; Xu, J.; Shteyngart, S.; Eckert, H.

1994-01-01

Cylindrical shells exhibit buckling under axial loads at stresses much less than the respective theoretical critical stresses. This is due primarily to the presence of geometrical imperfections even though such imperfections could be very small (e.g., comparable to thickness). Under internal pressure, the shell regains some of its buckling strength. For a relatively large radius-to-thickness ratio and low internal pressure, the effect can be reasonably estimated by an elastic analysis. However, for low radius-to-thickness ratios and greater pressures, the elastic-plastic collapse controls the failure load. in order to quantify the elastic-plastic buckling capacity of cylindrical shells, an analysis program was carried out by use of the computer code BOSOR5 developed by Bushnell of Lockheed Missiles and Space Company. The analysis was performed for various radius-to-thickness ratios and imperfection amplitudes. The purpose of the analytical program was to compute the buckling strength of underground cylindrical tanks, that are used for storage of nuclear wastes, for realistic geometric imperfections and internal pressure loads. This paper presents the results of the elastic-plastic analyses and compares them with other available information for various pressure loads

Plastic Zone Analysis of Deep-Buried, Noncircular Tunnel and Application on the High-Speed Railway in the Karst Area

Directory of Open Access Journals (Sweden)

Hai Shi

2017-01-01

Full Text Available With the conformal mapping function provided by Verruijt, the outland of a noncircular tunnel can be mapped to a circular unit in the complex plane and then spread the analytic function into a Laurent series. The stress unified solution of oval and horseshoe cross section can be determined using Muskhelishvili’s complex variables function method. Subsequently, the solution can be taken into the Griffith strength failure criterion and determine the scale and shape of plastic zone in the tunnel surrounding rock. Aiming at the critical safety thickness between a concealed cave and tunnel in the karst area and determining whether the plastic zone of tunnel surrounding rock is connected with the plastic zone of cave as a judgment standard, the model of critical safety thickness among the concealed caves and tunnels is established. The numerical model is established in comparison with the computing method of rock plate critical safety thickness in actual engineering based on the Doumo tunnel engineering of Shanghai-Kunming (Guizhou segment high-speed railway. The following conclusions can be drawn: the analytical approximation method has less indexes, and the output of this method is approximately close to actual engineering and numerical analysis, in which it is reliable and rational.

Analytical Solution of Tunnel Surrounding Rock for Stress and Displacement Based on Lade–Duncan Criterion

Directory of Open Access Journals (Sweden)

MingZheng Zhu

2018-01-01

Full Text Available The deformation and failure of tunnel surrounding rock is the result of tunnel excavation disturbance and rock stress release. When the local stress of surrounding rock exceeds the elastic limit of rock mass, the plastic analysis of surrounding rock must be carried out to judge the stability of tunnel. In this study, the Lade–Duncan yield criterion is used to calculate the analytic solutions for the surrounding rock in a tunnel, and the radius and displacement of the plastic zone are deduced using an equilibrium equation. The plastic zone radius and displacement based on Lade–Duncan criterion and Mohr–Coulomb criterion were compared by using single-factor analysis method under the different internal friction angles, in situ stresses, and support resistances. The results show that the solutions of the radius and displacement of plastic zone calculated by the Lade–Duncan criterion are close to those of Mohr–Coulomb criterion under the high internal friction angle and support resistance or low in situ rock stress; however, the radius and displacement of the plastic zone calculated by the Lade–Duncan criterion are larger under normal circumstances, and the Lade–Duncan criterion is more applicable to the stability analysis of the surrounding rock in a tunnel.

Finite element modeling of indentation-induced superelastic effect using a three-dimensional constitutive model for shape memory materials with plasticity

International Nuclear Information System (INIS)

Zhang, Yijun; Cheng, Yang-Tse; Grummon, David S.

2007-01-01

Indentation-induced shape memory and superelastic effects are recently discovered thermo-mechanical behaviors that may find important applications in many areas of science and engineering. Theoretical understanding of these phenomena is challenging because both martensitic phase transformation and slip plasticity exist under complex contact loading conditions. In this paper, we develop a three-dimensional constitutive model of shape memory alloys with plasticity. Spherical indentation-induced superelasticity in a NiTi shape memory alloy was simulated and compared to experimental results on load-displacement curves and recovery ratios. We show that shallow indents have complete recovery upon unloading, where the size of the phase transformation region is about two times the contact radius. Deep indents have only partial recovery when plastic deformation becomes more prevalent in the indent-affected zone

Geohydromechanical Processes in the Excavation Damaged Zone in Crystalline Rock, Rock Salt, and Indurated and Plastic Clays

International Nuclear Information System (INIS)

Tsang, Chin-Fu; Bernier, Frederic; Davies, Christophe

2004-01-01

The creation of an excavation disturbed zone or excavation damaged zone is expected around all man-made openings in geologic formations. Macro- and micro-fracturing, and in general a redistribution of in situ stresses and rearrangement of rock structures, will occur in this zone, resulting in drastic changes of permeability to flow, mainly through the fractures and cracks induced by excavation. Such an EDZ may have significant implications for the operation and long-term performance of an underground nuclear waste repository. Various issues of concern need to be evaluated, such as processes creating fractures in the excavation damaged zone, the degree of permeability increase, and the potential for sealing or healing (with permeability reduction) in the zone. In recent years, efforts along these lines have been made for a potential repository in four rock types-crystalline rock, salt, indurated clay, and plastic clay-and these efforts have involved field, laboratory, and theoretical studies. The present work involves a synthesis of the ideas and issues that emerged from presentations and discussions on EDZ in these four rock types at a CLUSTER Conference and Workshop held in Luxembourg in November, 2003. First, definitions of excavation disturbed and excavation damaged zones are proposed. Then, an approach is suggested for the synthesis and intercomparison of geohydromechanical processes in the EDZ for the four rock types (crystalline rock, salt, indurated clay, and plastic clay). Comparison tables of relevant processes, associated factors, and modeling and testing techniques are developed. A discussion of the general state-of-the-art and outstanding issues are also presented. A substantial bibliography of relevant papers on the subject is supplied at the end of the paper

Some aspects of fracture assessment diagrams, plastic zone size corrections and contour integrals in post-yield fracture mechanics

International Nuclear Information System (INIS)

Ainsworth, R.A.

1981-03-01

The CEGB failure assessment route is briefly described and is shown to be consistent with a plastic zone size correction method. Modifications to the assessment route which have recently been suggested for describing the effects of thermal and residual stresses are examined. It is shown that the plastic zone size correction method may be used to include local thermal and residual stresses in the assessment route in a simple manner. The assessment route is compared with finite-element solutions for a thermal stress problem and with strip-yield model solutions for a residual stress problem. In using finite-element solutions there are different contour integral methods available for calculating a post-yield fracture parameter. The J-integral of Rice and the J*-integral of Blackburn are examined and compared and the appropriate parameter is identified. (author)

HABITABILITY OF EXOMOONS AT THE HILL OR TIDAL LOCKING RADIUS

International Nuclear Information System (INIS)

Hinkel, Natalie R.; Kane, Stephen R.

2013-01-01

Moons orbiting extrasolar planets are the next class of object to be observed and characterized for possible habitability. Like the host-planets to their host-star, exomoons have a limiting radius at which they may be gravitationally bound, or the Hill radius. In addition, they also have a distance at which they will become tidally locked and therefore in synchronous rotation with the planet. We have examined the flux phase profile of a simulated, hypothetical moon orbiting at a distant radius around the confirmed exoplanets μ Ara b, HD 28185 b, BD +14 4559 b, and HD 73534 b. The irradiated flux on a moon at its furthest, stable distance from the planet achieves its largest flux gradient, which places a limit on the flux ranges expected for subsequent (observed) moons closer in orbit to the planet. We have also analyzed the effect of planetary eccentricity on the flux on the moon, examining planets that traverse the habitable zone either fully or partially during their orbit. Looking solely at the stellar contributions, we find that moons around planets that are totally within the habitable zone experience thermal equilibrium temperatures above the runaway greenhouse limit, requiring a small heat redistribution efficiency. In contrast, exomoons orbiting planets that only spend a fraction of their time within the habitable zone require a heat redistribution efficiency near 100% in order to achieve temperatures suitable for habitability. This means that a planet does not need to spend its entire orbit within the habitable zone in order for the exomoon to be habitable. Because the applied systems comprise giant planets around bright stars, we believe that the transit detection method is most likely to yield an exomoon discovery

HABITABILITY OF EXOMOONS AT THE HILL OR TIDAL LOCKING RADIUS

Energy Technology Data Exchange (ETDEWEB)

Hinkel, Natalie R.; Kane, Stephen R., E-mail: natalie.hinkel@gmail.com [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)

2013-09-01

Moons orbiting extrasolar planets are the next class of object to be observed and characterized for possible habitability. Like the host-planets to their host-star, exomoons have a limiting radius at which they may be gravitationally bound, or the Hill radius. In addition, they also have a distance at which they will become tidally locked and therefore in synchronous rotation with the planet. We have examined the flux phase profile of a simulated, hypothetical moon orbiting at a distant radius around the confirmed exoplanets {mu} Ara b, HD 28185 b, BD +14 4559 b, and HD 73534 b. The irradiated flux on a moon at its furthest, stable distance from the planet achieves its largest flux gradient, which places a limit on the flux ranges expected for subsequent (observed) moons closer in orbit to the planet. We have also analyzed the effect of planetary eccentricity on the flux on the moon, examining planets that traverse the habitable zone either fully or partially during their orbit. Looking solely at the stellar contributions, we find that moons around planets that are totally within the habitable zone experience thermal equilibrium temperatures above the runaway greenhouse limit, requiring a small heat redistribution efficiency. In contrast, exomoons orbiting planets that only spend a fraction of their time within the habitable zone require a heat redistribution efficiency near 100% in order to achieve temperatures suitable for habitability. This means that a planet does not need to spend its entire orbit within the habitable zone in order for the exomoon to be habitable. Because the applied systems comprise giant planets around bright stars, we believe that the transit detection method is most likely to yield an exomoon discovery.

Calculation of plastic deformation of a conical shell with the transformation of inner surface into outer one

Directory of Open Access Journals (Sweden)

A. I. Uvarov

2014-01-01

Full Text Available An analytical model of plastic deformation of a conical shell with the transformation of internal surface into outer one was developed with a use of the kinematic method. The shell material was assumed to be perfectly plastic. The theory of thin shells and the kinematic theorem of limit equilibrium were utilized in this work. Both geometric and physical nonlinearities were taken into account. Dependences for calculating radius of curvature of the intensive deformation zones, value of chain ring deformation and values of the deforming force as a function of axial displacement were determined. Analysis showed the possibility of using a conical shell to absorb energy with high efficiency. Obtained results could be used for calculation and selection of optimal parameters of the energy-absorbing elements in shock absorbers.

Computational strain gradient crystal plasticity

DEFF Research Database (Denmark)

Niordson, Christian Frithiof; Kysar, Jeffrey W.

2014-01-01

A numerical method for viscous strain gradient crystal plasticity theory is presented, which incorporates both energetic and dissipative gradient effects. The underlying minimum principles are discussed as well as convergence properties of the proposed finite element procedure. Three problems...... of plane crystal plasticity are studied: pure shear of a single crystal between rigid platens as well as plastic deformation around cylindrical voids in hexagonal close packed and face centered cubic crystals. Effective in-plane constitutive slip parameters for plane strain deformation of specifically...... oriented face centered cubic crystals are developed in terms of the crystallographic slip parameters. The effect on geometrically necessary dislocation structures introduced by plastic deformation is investigated as a function of the ratio of void radius to plasticity length scale....

Study of the external parameters influence on the channel discharge radius in Hg lamps

International Nuclear Information System (INIS)

Cristea, M.

2000-01-01

In this paper, the plasma electric conductivity and the channel radius for high-pressure mercury arc discharge are calculated. The examined model emphasizes some correlations between various external parameters (current intensity, silicon tube diameter and working pressure) and the channel discharge radius. After model validation, the temperature distribution in the discharge zone is obtained and then the electrons and ions distribution, the electric carriers mobility and the electric conductivity for different lamp characteristics are calculated. The applied numerical simulation shows a linear increase of the channel radius with the tube radius Rw increasing, and a very week pressure dependence (in the range 0.5 - 5 atm.)

Determination of post-shakedown quantities of a pipe bend via the simplified theory of plastic zones compared with load history dependent incremental analysis

Science.gov (United States)

Vollrath, Bastian; Hübel, Hartwig

2018-01-01

The Simplified Theory of Plastic Zones (STPZ) may be used to determine post-shakedown quantities such as strain ranges and accumulated strains at plastic or elastic shakedown. The principles of the method are summarized. Its practical applicability is shown by the example of a pipe bend subjected to constant internal pressure along with cyclic in-plane bending or/and cyclic radial temperature gradient. The results are compared with incremental analyses performed step-by-step throughout the entire load history until the state of plastic shakedown is achieved.

Biofilm and Diatom Succession on Polyethylene (PE) and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

Science.gov (United States)

Eich, Andreas; Mildenberger, Tobias; Laforsch, Christian; Weber, Miriam

2015-01-01

The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth) and a pelagic habitat (3 m water depth) to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM) analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation and composition

Biofilm and Diatom Succession on Polyethylene (PE and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

Directory of Open Access Journals (Sweden)

Andreas Eich

Full Text Available The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth and a pelagic habitat (3 m water depth to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation

On the relationship between stress intensity factor (K) and minimum ...

African Journals Online (AJOL)

Studies on crack-tip plastic zones are of fundamental importance in describing the process of failure and in formulating various fracture criteria. Minimum plastic zone radius (MPZR) theory is widely used in prediction of crack initiation angle in mixed mode fracture analysis of engineering materials. In this study, shape and ...

Clarification on shear transformation zone size and its correlation with plasticity for Zr-based bulk metallic glass in different structural states

Energy Technology Data Exchange (ETDEWEB)

Chen, Z.Q.; Huang, L. [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China); Huang, P., E-mail: huangping@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China); Xu, K.W. [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, F., E-mail: wangfei@mail.xjtu.edu.cn [State Key Laboratory for Strength and Vibration of Mechanical Structures Xi' an Jiaotong University, Xi' an 710049 (China); Lu, T.J. [State Key Laboratory for Strength and Vibration of Mechanical Structures Xi' an Jiaotong University, Xi' an 710049 (China); MOE Key Laboratory for Multifunctional Materials and Structures Xi' an Jiaotong University, Xi' an 710049 (China)

2016-11-20

To clarify the real size of shear transformation zone (STZ) and its correlation with the plasticity of metallic glass, STZ sizes of a Zr-based bulk metallic glass (BMG) in three different structural states (as-cast, annealed and confining annealed) were examined using both rate-change and statistical methods upon nanoindentation. STZ sizes (less than 24 atoms) obtained by the statistical method approached the real STZ size of very few atoms, and showed no correlation with BMG plasticity. In sharp contrast, STZ sizes (hundreds of atoms) obtained by the rate-change method not only were much larger than the real STZ size but also exhibited a positive correlation with BMG plasticity. These discrepancies were discussed in terms of the structural evolution of BMGs upon nanoindentation.

Description and application of capture zone delineation for a wellfield at Hilton Head Island, South Carolina

Science.gov (United States)

Landmeyer, J.E.

1994-01-01

Ground-water capture zone boundaries for individual pumped wells in a confined aquffer were delineated by using groundwater models. Both analytical and numerical (semi-analytical) models that more accurately represent the $round-water-flow system were used. All models delineated 2-dimensional boundaries (capture zones) that represent the areal extent of groundwater contribution to a pumped well. The resultant capture zones were evaluated on the basis of the ability of each model to realistically rapresent the part of the ground-water-flow system that contributed water to the pumped wells. Analytical models used were based on a fixed radius approach, and induded; an arbitrary radius model, a calculated fixed radius model based on the volumetric-flow equation with a time-of-travel criterion, and a calculated fixed radius model derived from modification of the Theis model with a drawdown criterion. Numerical models used induded the 2-dimensional, finite-difference models RESSQC and MWCAP. The arbitrary radius and Theis analytical models delineated capture zone boundaries that compared least favorably with capture zones delineated using the volumetric-flow analytical model and both numerical models. The numerical models produced more hydrologically reasonable capture zones (that were oriented parallel to the regional flow direction) than the volumetric-flow equation. The RESSQC numerical model computed more hydrologically realistic capture zones than the MWCAP numerical model by accounting for changes in the shape of capture zones caused by multiple-well interference. The capture zone boundaries generated by using both analytical and numerical models indicated that the curnmtly used 100-foot radius of protection around a wellhead in South Carolina is an underestimate of the extent of ground-water capture for pumped wetis in this particular wellfield in the Upper Floridan aquifer. The arbitrary fixed radius of 100 feet was shown to underestimate the upgradient

Elastic-plastic analysis of the toroidal field coil inner leg of the compact ignition tokamak

International Nuclear Information System (INIS)

Horie, T.

1987-07-01

Elastic-plastic analyses were made for the inner leg of the Compact Ignition Tokamak toroidal field (TF) coil, which is made of copper-Inconel composite material. From the result of the elastic-plastic analysis, the effective Young's moduli of the inner leg were determined by the analytical equations. These Young's moduli are useful for the three-dimensional, elastic, overall TF coil analysis. Comparison among the results of the baseline design (R = 1.324 m), the bucked pressless design, the 1.527-m major radius design, and the 1.6-m major radius design was also made, based on the elastic-plastic TF coil inner leg analyses

33 CFR 165.103 - Safety and Security Zones; LPG Vessel Transits in Portland, Maine, Captain of the Port Zone...

Science.gov (United States)

2010-07-01

... within a 500-yard radius of any Liquefied Petroleum Gas (LPG) vessel while it is moored at the LPG... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety and Security Zones; LPG... and Security Zones; LPG Vessel Transits in Portland, Maine, Captain of the Port Zone, Portsmouth...

Radius crossover sign: an indication of malreduced radius shaft greenstick fractures.

Science.gov (United States)

Wright, Patrick B; Crepeau, Allison E; Herrera-Soto, José A; Price, Charles T

2012-06-01

Radius shaft greenstick fractures in children can be a challenging injury to treat because angulation and rotational alignment are difficult to assess. In this report, we describe a simple method for analyzing the deformity and identifying rotational and angular malalignment. This technique involves analyzing the forearm radiographs as 2 segments, proximal and distal, and assuring that the rotational position of each matches the other. We present 3 cases of proximal radius greenstick fractures in malalignment to demonstrate the radius crossover sign. Identifying the radius crossover sign, and proceeding with further closed reduction may prevent deformity that could otherwise result in a significant loss of forearm motion. Level V.

PLASTIC ANALYSIS OF STEEL FRAME STRUCTURE

Directory of Open Access Journals (Sweden)

M. Rogac

2013-05-01

Full Text Available This paper presents the plastic analysis of steel frame structure loaded by gravity loads. By applying the cinematic theorem of ultimate analysis, the ultimate load for the case of elastic - ideally plastic material is calculated. The identical structure was treated in the computer program SAP2000 where the zone of material reinforcement in the plastic area was covered. Keywords: Steel frame structure, plastic analysis, ultimate gravity load, material reinforcement.

An accurate tangential force-displacement model for granular-flow simulations: Contacting spheres with plastic deformation, force-driven formulation

International Nuclear Information System (INIS)

Vu-Quoc, L.; Lesburg, L.; Zhang, X.

2004-01-01

An elasto-plastic frictional tangential force-displacement (TFD) model for spheres in contact for accurate and efficient granular-flow simulations is presented in this paper; the present TFD is consistent with the elasto-plastic normal force-displacement (NFD) model presented in [ASME Journal of Applied Mechanics 67 (2) (2000) 363; Proceedings of the Royal Society of London, Series A 455 (1991) (1999) 4013]. The proposed elasto-plastic frictional TFD model is accurate, and is validated against non-linear finite-element analyses involving plastic flows under both loading and unloading conditions. The novelty of the present TFD model lies in (i) the additive decomposition of the elasto-plastic contact area radius into an elastic part and a plastic part, (ii) the correction of the particles' radii at the contact point, and (iii) the correction of the particles' elastic moduli. The correction of the contact-area radius represents an effect of plastic deformation in colliding particles; the correction of the radius of curvature represents a permanent indentation after impact; the correction of the elastic moduli represents a softening of the material due to plastic flow. The construction of both the present elasto-plastic frictional TFD model and its consistent companion, the elasto-plastic NFD model, parallels the formalism of the continuum theory of elasto-plasticity. Both NFD and TFD models form a coherent set of force-displacement (FD) models not available hitherto for granular-flow simulations, and are consistent with the Hertz, Cattaneo, Mindlin, Deresiewicz contact mechanics theory. Together, these FD models will allow for efficient simulations of granular flows (or granular gases) involving a large number of particles

Seismic cycle feedbacks in a mid-crustal shear zone

Science.gov (United States)

Melosh, Benjamin L.; Rowe, Christie D.; Gerbi, Christopher; Smit, Louis; Macey, Paul

2018-07-01

Mid-crustal fault rheology is controlled by alternating brittle and plastic deformation mechanisms, which cause feedback cycles that influence earthquake behavior. Detailed mapping and microstructural observations in the Pofadder Shear Zone (Namibia and South Africa) reveal a lithologically heterogeneous shear zone core with quartz-rich mylonites and ultramylonites, plastically overprinted pseudotachylyte and active shear folds. We present evidence for a positive feedback cycle in which coseismic grain size reduction facilitates active shear folding by enhancing competency contrasts and promoting crystal plastic flow. Shear folding strengthens a portion of a shear zone by limb rotation, focusing deformation and promoting plastic flow or brittle slip in resulting areas of localized high stress. Using quartz paleopiezometry, we estimate strain and slip rates consistent with other studies of exhumed shear zones and modern plate boundary faults, helping establish the Pofadder Shear Zone as an ancient analogue to modern, continental-scale, strike-slip faults. This feedback cycle influences seismicity patterns at the scale of study (10s of meters) and possibly larger scales as well, and contributes to bulk strengthening of the brittle-plastic transition on modern plate boundary faults.

A numerical basis for strain-gradient plasticity theory: Rate-independent and rate-dependent formulations

DEFF Research Database (Denmark)

Nielsen, Kim Lau; Niordson, Christian Frithiof

2014-01-01

of a single plastic zone is analyzed to illustrate the agreement with earlier published results, whereafter examples of (ii) multiple plastic zone interaction, and (iii) elastic–plastic loading/unloading are presented. Here, the simple shear problem of an infinite slab constrained between rigid plates......A numerical model formulation of the higher order flow theory (rate-independent) by Fleck and Willis [2009. A mathematical basis for strain-gradient plasticity theory – part II: tensorial plastic multiplier. Journal of the Mechanics and Physics of Solids 57, 1045-1057.], that allows for elastic–plastic...... loading/unloading and the interaction of multiple plastic zones, is proposed. The predicted model response is compared to the corresponding rate-dependent version of visco-plastic origin, and coinciding results are obtained in the limit of small strain-rate sensitivity. First, (i) the evolution...

77 FR 31493 - Safety Zones; Fourth of July Fireworks Displays Within the Captain of the Port Charleston Zone, SC

Science.gov (United States)

2012-05-29

... temporary safety zones during Fourth of July Fireworks Displays on certain navigable waterways in Hilton... below. 1. Hilton Head Island, South Carolina. All waters within a 500 yard radius around the barge from... each safety zone. All coordinates are North American Datum 1983. [[Page 31496

Plastic Accumulation in the Mediterranean Sea

OpenAIRE

C?zar, Andr?s; Sanz-Mart?n, Marina; Mart?, Elisa; Gonz?lez-Gordillo, J. Ignacio; Ubeda, B?rbara; G?lvez, Jos? ?.; Irigoien, Xabier; Duarte, Carlos M.

2015-01-01

Copyright: © 2015 Cózar et al. Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by ...

Spatial distribution, input and dispersion of plastic pellets in coastal zones

OpenAIRE

Danilo Balthazar Silva

2016-01-01

The production and the usage of plastic material increases since the decade of 1950. Nowadays, the elevated production rate, the misusing and the waste turned plastic material in an urgent environmental and economic problem. One of the major environmental problems related to this issue is the contamination of marine environments by microplastics. These constitute plastic particles of size between 1 and 5 mm. Microplastics might occur by breaking of larger plastic pieces or as a manufactured p...

Higher harmonic imaging of tensile plastic deformation in loading and reloading processes by local resonance method

International Nuclear Information System (INIS)

Kawashima, Koichiro; Yasui, Hajime

2015-01-01

We have imaged plastically deformed region in a 5052 aluminum plate under tensile loading, unloading and reloading processes by using an immersion local resonance method. By transmitting large-amplitude burst wave of which frequency is a through-thickness resonant frequency of the plate, dislocation loops in plastic zone are forced to vibrate. The higher harmonic amplitude excited by the dislocation movement is mapped for the transducer position. The extension of plastic zone under monotonically increased loading, decrease in harmonic amplitude under unloading process and marked extension of plastic zone in reloading up to 0.4% plastic strain are clearly imaged. (author)

Slip Zone versus Damage Zone Micromechanics, Arima-Takasuki Tectonic Line, Japan

Science.gov (United States)

White, J. C.; Lin, A.

2017-12-01

The Arima-Takasuki Tectonic Line (ATTL) of southern Honshu, Japan is defined by historically active faults and multiple splays producing M7 earthquakes. The damage zone of the ATTL comprises a broad zone of crushed, comminuted and pulverized granite/rhyolite1,2containing cm-scale slip zones and highly comminuted injection veins. In this presentation, prior work on the ATTL fault rocks is extending to include microstructural characterization by transmission electron microscopy (TEM) from recent trenching of the primary slip zone, as well as secondary slip zones. This is necessary to adequately characterize the extremely fine-grained material (typically less than 1mm) in both damage and core zones. Damage zone material exhibits generally random textures3 whereas slip zones are macroscopically foliated, and compositionally layered, notwithstanding a fairly homogeneous protolith. The latter reflects fluid-rock interaction during both coseismic and interseismic periods. The slip zones are microstructurally heterogeneous at all scales, comprising not only cataclasites and phyllosilicate (clay)-rich gouge zones, but Fe/Mn pellets or clasts that are contained within gouge. These structures appear to have rolled and would suggest rapid recrystallization and/or growth. A central question related to earthquake recurrence along existing faults is the nature of the gouge. In both near-surface exposures and ongoing drilling at depth, "plastic" or "viscous" gouge zones comprise ultra-fine-grained clay-siliciclastic particles that would not necessarily respond in a simple frictional manner. Depending on whether the plastic nature of these slip zones develops during or after slip, subsequent focusing of slip within them could be complicated. 1 Mitchell, T.A., Ben-Zion, Y., Shimamoto, T., 2011. Ear. Planet. Sci. Lett. 308, 284-297. 2 Lin, A., Yamashita, K, Tanaka, M. J., 2013. Struc. Geol. 48, 3-13. 3 White, J.C., Lin, A. 2016. Proc. AGU Fall Mtg., T42-02 San Francisco.

A study of microindentation hardness tests by mechanism-based strain gradient plasticity

International Nuclear Information System (INIS)

Huang, Y.; Xue, Z.; Gao, H.; Nix, W. D.; Xia, Z. C.

2000-01-01

We recently proposed a theory of mechanism-based strain gradient (MSG) plasticity to account for the size dependence of plastic deformation at micron- and submicron-length scales. The MSG plasticity theory connects micron-scale plasticity to dislocation theories via a multiscale, hierarchical framework linking Taylor's dislocation hardening model to strain gradient plasticity. Here we show that the theory of MSG plasticity, when used to study micro-indentation, indeed reproduces the linear dependence observed in experiments, thus providing an important self-consistent check of the theory. The effects of pileup, sink-in, and the radius of indenter tip have been taken into account in the indentation model. In accomplishing this objective, we have generalized the MSG plasticity theory to include the elastic deformation in the hierarchical framework. (c) 2000 Materials Research Society

Taylor-plasticity-based analysis of length scale effects in void growth

KAUST Repository

Liu, Junxian; Demiral, Murat; El Sayed, Tamer S.

2014-01-01

plasticity as the flow rule, the critical cavitation condition, appearing when the derivative of the externally imposed mean stress with respect to the current void radius becomes zero, is rewritten analytically according to the Leibniz relation and found

CANDIDATE PLANETS IN THE HABITABLE ZONES OF KEPLER STARS

International Nuclear Information System (INIS)

Gaidos, Eric

2013-01-01

A key goal of the Kepler mission is the discovery of Earth-size transiting planets in ''habitable zones'' where stellar irradiance maintains a temperate climate on an Earth-like planet. Robust estimates of planet radius and irradiance require accurate stellar parameters, but most Kepler systems are faint, making spectroscopy difficult and prioritization of targets desirable. The parameters of 2035 host stars were estimated by Bayesian analysis and the probabilities p HZ that 2738 candidate or confirmed planets orbit in the habitable zone were calculated. Dartmouth Stellar Evolution Program models were compared to photometry from the Kepler Input Catalog, priors for stellar mass, age, metallicity and distance, and planet transit duration. The analysis yielded probability density functions for calculating confidence intervals of planet radius and stellar irradiance, as well as p HZ . Sixty-two planets have p HZ > 0.5 and a most probable stellar irradiance within habitable zone limits. Fourteen of these have radii less than twice the Earth; the objects most resembling Earth in terms of radius and irradiance are KOIs 2626.01 and 3010.01, which orbit late K/M-type dwarf stars. The fraction of Kepler dwarf stars with Earth-size planets in the habitable zone (η ⊕ ) is 0.46, with a 95% confidence interval of 0.31-0.64. Parallaxes from the Gaia mission will reduce uncertainties by more than a factor of five and permit definitive assignments of transiting planets to the habitable zones of Kepler stars.

Stagnant zone formation on diamond cutting tools during machining

International Nuclear Information System (INIS)

Izman, S.; Tamin, M.N.; Mon, T.T.; Venkatesh, V.C.; Shaharoun, A.M.

2007-01-01

Formation of an intact region on the rake face of cutting tool during machining is quite common phenomenon but its significance in maintaining tool edge sharpness has not been recognized by many researchers. This region is sometimes called stagnant zone. It is believed that when an intact zone present on the rake face, it delays the crater wear progress and hence maintaining the tool edge sharpness longer. This paper investigates the effect of edge radius, surface roughness of the rake face and cutting parameters on the formation of stagnant zone on two different type of diamond tools i.e. polycrystalline diamond PCD-KD100 and diamond-coated inserts when machining titanium alloy. The used inserta and post-processed chips were examined under FESEM and optical microscope after cutting at three different conditions. Experimental results show that the speed and feel, the tool edge radius, and the tool rake surface roughness significantly affect the stagnant zone formation. (author)

Dislocation-free zone model of fracture comparison with experiments

International Nuclear Information System (INIS)

Ohr, S.M.; Chang, S.

1982-01-01

The dislocation-free zone (DFZ) model of fracture has been extended to study the relationship between the stress intensity factor, extent of plastic deformation, and crack tip geometry of an elastic-plastic crack as a function of applied stress. The results show that the stress intensity factor K decreases from the elastic value at first slowly, then goes rapidly to zero as the number of dislocations in the plastic zone increases. The crack with a zero stress intensity factor has its crack tip stress field completely relaxed by plastic deformation and hence is called a plastic crack. Between the elastic and plastic cracks, a wide range of elastic-plastic cracks having both a stress singularity and a plastic zone are possible. These elastic-plastic cracks with a DFZ are predicted if there is a critical stress intensity factor K/sub g/ required for the generation of dislocations at the crack tip. The expression for K/sub g/ is obtained from the crack tip dislocation nucleation model of Rice and Thomson. In most metals, the magnitude of K/sub g/ is less than the critical stress intensity factor for brittle fracture K/sub c/. The values of K are determined from electron microscope fracture experiments for various metals and they are found to be in good agreement with the K/sub g/ predicted from the model. It is concluded that for most ductile and semibrittle metals, the mechanism of dislocation generation is more important than the fracture surface energy in determining the stress intensity factor at the crack tip

A biomechanical comparison of four fixed-angle dorsal plates in a finite element model of dorsally-unstable radius fracture.

Science.gov (United States)

Knežević, Josip; Kodvanj, Janoš; Čukelj, Fabijan; Pamuković, Frane; Pavić, Arsen

2017-11-01

To compare the finite element models of two different composite radius fracture patterns, reduced and stabilised with four different fixed-angle dorsal plates during axial, dorsal and volar loading conditions. Eight different plastic models representing four AO/ASIF type 23-A3 distal radius fractures and four AO/ASIF 23-C2 distal radius fractures were obtained and fixed each with 1 of 4 methods: a standard dorsal non-anatomical fixed angle T-plate (3.5mm Dorsal T-plate, Synthes), anatomical fixed-angle double plates (2.4mm LCP Dorsal Distal Radius, Synthes), anatomical fixed angle T-plate (2.4mm Acu-Loc Dorsal Plate, Acumed) or anatomical variable-angle dorsal T-plate (3.5mm, Dorsal Plate, Zrinski). Composite radius with plate and screws were scanned with a 3D optical scanner and later processed in Abaqus Software to generate the finite element model. All models were axially loaded at 3 points (centrally, volarly and dorsally) with 50 N forces to avoid the appearance of plastic deformations of the models. Total displacements at the end of the bone and the stresses in the bones and plates were determined and compared. Maximal von Mises stress in bone for 3-part fracture models was very similar to that in 2-part fracture models. The biggest difference between models and the largest displacements were seen during volar loading. The stresses in all models were the highest above the fracture gap. The best performance in all parameters tested was with the Zrinski plate and the most modest results were with the Synthes T-plate. There was no significant difference between 2-part (AO/ASIF type 23-A3) and 3-part (AO/ASIF 23-C2) fracture models. Maximal stresses in the plates appeared above the fracture gap; therefore, it is worth considering the development of plates without screw holes above the gap. © 2017 Elsevier Ltd. All rights reserved.

Numerical calculation procedure for criticality parameters of the two-zone reflected reactor with flat central zone

International Nuclear Information System (INIS)

Bosevski, T.; Strugar, P.

1966-10-01

In determining the criticality parameters of a two-zone reactor with flat central zone one encounters a numerical problem requiring the solution of a system of two non-linear equations. To solve them the Newton method, which proved convenient, was used n this work. By comparing our results with those reported one obtains about 5% smaller values of both the radius of the flat zone and of the radial buckling of the outer zone. This discrepancy probably results from some approximations used in solving the same system of equations used in solving the same system of equations where the procedure form was applied, whereas the calculation time is by one order of magnitude smaller

Plastic strain caused by contraction of pores in polycrystalline graphites

International Nuclear Information System (INIS)

Ioka, Ikuo; Yoda, Shinichi; Konishi, Takashi.

1989-01-01

The effects of porosity on mechanical properties and deformation behavior of four isotropic polycrystalline graphites were studied. The pore size distributions of the graphites were measured using a conventional mercury penetration technique. The average pore radius of ISO-88 graphite was about one-tenth of that of ISEM-1, IG-11 or IG-15 graphites. Young's modulus of the graphites decreased with increasing porosity. The stress-strain curve of each graphite was measured in its lateral and axial directions. Young's modulus of graphite decreased with increasing load. The plastic strain at a given compressive load was calculated from the stress-strain curve and the initial gradient of the unloading curve at the load. The ratio of lateral plastic strain to axial plastic strain for the graphites was less than 0.5, indicating that the volume of the graphites decreased during compressive loading. By assuming that the volume change was caused by contraction of pores, plastic strain associated with contraction of pores was calculated from the axial plastic strain and lateral plastic strain by slips along the basal planes. The plastic strain increased with increasing axial plastic strain and porosity of graphite. (author)

Lucas Heights buffer zone: plan of management

International Nuclear Information System (INIS)

1986-01-01

This plan is being used by the Commission as a guide for its management of the Lucas Heights buffer zone, which is essentially a circular area having a 1-6 km radius around the HIFAR reactor. Aspects covered by this plan include past uses, current use, objectives for buffer zone land management, emergency evacuation, resource conservation, archaeology, fire, access, rehabilitation of disturbed areas, resource management and plan implementation

Effect of finite edge radius on ductile fracture ahead of the cutting tool edge in micro-cutting of Al2024-T3

International Nuclear Information System (INIS)

Subbiah, Sathyan; Melkote, Shreyes N.

2008-01-01

Evidence of ductile fracture leading to material separation has been reported recently in ductile metal cutting [S. Subbiah, S.N. Melkote, ASME J. Manuf. Sci. Eng. 28(3) (2006)]. This paper investigates the effect of finite edge radius on such ductile fracture. The basic question of whether such ductile fracture occurs in the presence of a finite edge radius is explored by performing a series of experiments with inserts of different edge radii at various uncut chip thickness values ranging from 15 to 105 μm. Chip-roots are obtained in these experiments using a quick-stop device and examined in a scanning electron microscope. Clear evidence of material separation is seen at the interface zone between the chip and machined surface even when the edge radius is large compared to the uncut chip thickness. Failure is seen to occur at the upper, middle, and/or the lower edges of the interface zone. Based on these observations, a hypothesis is presented for the events leading to the occurrence of this failure when cutting with an edge radius tool. Finite element simulations are performed to study the nature of stress state ahead of the tool edge with and without edge radius. Hydrostatic stress is seen to be tensile in front of the tool and hence favors the occurrence of ductile fracture leading to material separation. The stress components are, however lower than those seen with a sharp tool

Plastic accumulation in the Mediterranean sea.

Directory of Open Access Journals (Sweden)

Andrés Cózar

Full Text Available Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2, as well as its frequency of occurrence (100% of the sites sampled, are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

Plastic Accumulation in the Mediterranean Sea

KAUST Repository

Có zar, André s; Sanz-Martí n, Marina; Martí , Elisa; Gonzá lez-Gordillo, J. Ignacio; Ubeda, Bá rbara; Gá lvez, José Á .; Irigoien, Xabier; Duarte, Carlos M.

2015-01-01

Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

Plastic Accumulation in the Mediterranean Sea

KAUST Repository

Cózar, Andrés

2015-04-01

Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

Plastic accumulation in the Mediterranean sea.

Science.gov (United States)

Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J Ignacio; Ubeda, Bárbara; Gálvez, José Á; Irigoien, Xabier; Duarte, Carlos M

2015-01-01

Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

Plastic Accumulation in the Mediterranean Sea

Science.gov (United States)

Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J. Ignacio; Ubeda, Bárbara; Gálvez, José Á.; Irigoien, Xabier; Duarte, Carlos M.

2015-01-01

Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region. PMID:25831129

Hybrid friction stir welding for dissimilar materials through electro-plastic effect

Science.gov (United States)

Liu, Xun; Lan, Shuhuai; Ni, Jun

2018-05-29

A hybrid Friction Stir Welding approach and device for dissimilar materials joining employing Electro-Plastic Effect. The approach and device include an introduction of high density, short period current pulses into traditional friction stir welding process, which therefore can generate a localized softened zone in the workpiece during plastic stirring without significant additional temperature increase. This material softened zone is created by high density current pulses based on Electro-Plastic Effect and will move along with the friction stir welding tool. Smaller downward force, larger processing window and better joint quality for dissimilar materials are expected to be achieved through this hybrid welding technique.

Demographic survey around proposed nuclear power plant site in Haryana covering 30 km radius area from the site

International Nuclear Information System (INIS)

Garg, V.K.

2013-01-01

This study was planned to have a demographic survey of the households living within 30 km radius of the proposed site. Objectives of the present study were to attain the quantitative baseline demographic data around (within 30 km radius) the proposed site of nuclear power plant, zone-wise and sector-wise distribution of the population around proposed site up to a distance of 30 km from the site, to obtain the data on socio-economic, cultural, and religious perspectives of the target populations, to obtain the data on disease/illness pattern in the target population, health status and mortality rate

Plastic debris in the open ocean

OpenAIRE

Cózar, Andrés; Echevarría, Fidel; González-Gordillo, J. Ignacio; Irigoien, Xabier; Úbeda, Bárbara; Hernández-León, Santiago; Palma, Álvaro T.; Navarro, Sandra; García-de-Lomas, Juan; Ruiz, Andrea; Fernández-de-Puelles, María L.; Duarte, Carlos M.

2014-01-01

There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. Howeve...

Fracture toughness evaluation of small notched specimen in consideration of notch effect and loading rate

International Nuclear Information System (INIS)

Lee, Baik Woo; Kwon, Dong Il; Jang, Jae Il

2000-01-01

Notch effect and loading rate dependency on fracture toughness were considered when evaluating fracture toughness of small notched specimens using the instrumented impact test. Notch effect was analyzed into stress redistribution effect and stress relaxation with a viewpoint of stress triaxiality. Stress redistribution effect was corrected by introducing effective crack length, which was the sum of actual crack length and plastic zone size. Stress relaxation effect was also corrected using elastic stress concentration factor, which would decrease if plastic deformation occurred. As a result, corrected fracture toughness of the notched specimen was very consistent with the reference fracture toughness obtained using precracked specimen. In addition, limiting notch root radius, below which fracture toughness was independent of notch radius, was observed and discussed. Loading rate dependency on fracture toughness, which was obtained from the static three point bending test and the instrumented impact test, was also discussed with stress field in plastic zone ahead of a notch and fracture based on stress control mechanism. (author)

Improved airline-type supplied-air plastic suit

International Nuclear Information System (INIS)

Jolley, L. Jr.; Zippler, D.B.; Cofer, C.H.; Harper, J.A.

1978-06-01

Two piece supplied-air plastic suits are used extensively at the Savannah River Plant for personnel protection against inhalation of airborne plutonium and tritium. Worker comfort and noise level problems gave impetus to development of an improved suit and aid distribution system. The resulting plastic suit and development work are discussed. The plastic suit unit cost is less than $20, the hearing zone noise level is less than 75 dBA, protection factors exceed 10,000, and user comfort is approved. This suit is expected to meet performance requirements for unrestricted use

Pilot fire radius size and its variation regarding the uncertainty in fire risk assessment

International Nuclear Information System (INIS)

Argirov, J.

1998-01-01

The impact of a combustible load with limited amount of heat on the characteristics of fire generated local environment is considered. The combustible load apportionment on the floor and its ability to release the heat at a different rate regarding the temperatures and heat flux in zones formed in the NPP compartments is studied using calculations. Several ways of variation of a pilot fire radius in the same range are compared. (author)

Ever-changing proton radius?

Energy Technology Data Exchange (ETDEWEB)

Mihovilovic, Miha [Institut fuer Kernphysik, Johannes-Gutenberg-Universitaet, Mainz (Germany)

2016-07-01

The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the presently best value obtained from elastic scattering experiments remains unexplained and represents a burning problem of today's nuclear physics. Therefore, several new experiments are underway, committed to provide new insight into the problem. High-precision electron scattering experiments are in progress at the Jefferson Lab and the Mainz Microtron. As a counterpart to these measurements, a muon-proton scattering experiment is envisioned at the Paul Scherrer Institute. Together with the nuclear scattering experiments, new atomic measurements are underway at the Max Planck Institute in Garching, which aim to further improve also the spectroscopic results on electronic hydrogen. These experiments are complemented by extensive theoretical efforts focused on studying various processes contributing to the atomic Lamb shift measurements that could explain the difference, as well as on pursuing different ways to interpret nuclear form-factor measurements, which could lead to a consistent value of the radius. In this presentation the currently best proton radius measurements are summarized, and the importance of the observed inconsistency between the hydrogen and the muonic-hydrogen data is discussed. Selected new experiments dedicated to remeasuring the radius are described, and the results of the MAMI experiment are presented.

77 FR 43167 - Safety Zone; Electric Zoo Fireworks, East River, Randall's Island, NY

Science.gov (United States)

2012-07-24

... establishes a temporary safety zone on the waters of the East River in the vicinity of Randall's Island, NY.... This temporary safety zone will restrict vessels from a portion of the East River around the location... area is a temporary safety zone: all navigable waters of the East River within a 164-yard radius of the...

Puzzling out the proton radius puzzle

Directory of Open Access Journals (Sweden)

Mihovilovič Miha

2014-01-01

Full Text Available The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today’s nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described.

Puzzling out the proton radius puzzle

Energy Technology Data Exchange (ETDEWEB)

Mihovilovič, M.; Merkel, H.; Weber, A. [Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 45, 55128 Mainz (Germany)

2016-01-22

The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today’s nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described.

Nuclear charge radius of $^{12}$Be

CERN Document Server

Krieger, Andreas; Bissell, Mark L; Frömmgen, Nadja; Geppert, Christopher; Hammen, Michael; Kreim, Kim; Kowalska, Magdalena; Krämer, Jörg; Neff, Thomas; Neugart, Rainer; Neyens, Gerda; Nörtershäuser, Wilfried; Novotny, Christian; Sanchez, Rodolfo; Yordanov, Deyan T

2012-01-01

The nuclear charge radius of $^{12}$Be was precisely determined using the technique of collinear laser spectroscopy on the $2s_{1/2}\\rightarrow 2p_{1/2, 3/2}$ transition in the Be$^{+}$ ion. The mean square charge radius increases from $^{10}$Be to $^{12}$Be by $\\delta ^{10,12} = 0.69(5)$ fm$^{2}$ compared to $\\delta ^{10,11} = 0.49(5)$ fm$^{2}$ for the one-neutron halo isotope $^{11}$Be. Calculations in the fermionic molecular dynamics approach show a strong sensitivity of the charge radius to the structure of $^{12}$Be. The experimental charge radius is consistent with a breakdown of the N=8 shell closure.

The expression of Helicobacter pylori tfs plasticity zone cluster is regulated by pH and adherence, and its composition is associated with differential gastric IL-8 secretion.

Science.gov (United States)

Silva, Bruno; Nunes, Alexandra; Vale, Filipa F; Rocha, Raquel; Gomes, João Paulo; Dias, Ricardo; Oleastro, Mónica

2017-08-01

Helicobacter pylori virulence is associated with different clinical outcomes. The existence of an intact dupA gene from tfs4b cluster has been suggested as a predictor for duodenal ulcer development. However, the role of tfs plasticity zone clusters in the development of ulcers remains unclear. We studied several H. pylori strains to characterize the gene arrangement of tfs3 and tfs4 clusters and their impact in the inflammatory response by infected gastric cells. The genome of 14 H. pylori strains isolated from Western patients, pediatric (n=10) and adult (n=4), was fully sequenced using the Illumina platform MiSeq, in addition to eight pediatric strains previously sequenced. These strains were used to infect human gastric cells, and the secreted interleukin-8 (IL-8) was quantified by ELISA. The expression of virB2, dupA, virB8, virB10, and virB6 was assessed by quantitative PCR in adherent and nonadherent fractions of H. pylori during in vitro co-infection, at different pH values. We have found that cagA-positive H. pylori strains harboring a complete tfs plasticity zone cluster significantly induce increased production of IL-8 from gastric cells. We have also found that the region spanning from virB2 to virB10 genes constitutes an operon, whose expression is increased in the adherent fraction of bacteria during infection, as well as in both adherent and nonadherent fractions at acidic conditions. A complete tfs plasticity zone cluster is a virulence factor that may be important for the colonization of H. pylori and to the development of severe outcomes of the infection with cagA-positive strains. © 2017 John Wiley & Sons Ltd.

Dynamic plastic buckling of cylindrical and spherical shells

International Nuclear Information System (INIS)

Jones, N.; Okawa, D.M.

1975-01-01

A theoretical analysis is developed to predict the dynamic plastic buckling of a long, impulsively loaded cylindrical shell in order to examine various features of plastic buckling and to assess the importance of several approximations with previous authors have introduced in dynamic plastic buckling studies. The influence of a time-dependent circumferential membrane force, the sharpness of the peaks in the displacement and velocity amplification functions, the restrictions which are implicit when employing the Prandtl-Reuss equations in this class of problems, and the limitations due to elastic unloading are examined in some detail. A summary of all previously published theoretical investigations known to the authors is undertaken for the dynamic plastic behavior of cylindrical shells and rings which are made from rigid-plastic, rigid-visco-plastic, elastic-plastic and elastic-visco-plastic materials and subjected to initial axisymmetric impulsive velocity fields. The theoretical predictions of the dominant motions, critical mode numbers, and threshold impulses are compared and critically reviewed. An experimental investigation was also undertaken into the dynamic plastic buckling of circular rings subjected to uniformly distributed external impulsive velocities. It appears that no experiments have been reported previously on mild steel cylindrical shells with an axial length (L) less than four times the shell radius (R). The experimental values of the average final radial deflections, critical mode numbers and dimensions of the permanent wrinkles in the mild steel and some aliminium 6,061 T6 specimens are compared with all the previously published theoretical predictions and experimental results on cylindrical shells with various axial lengths. (orig./HP) [de

Effects of plastic anisotropy on crack-tip behaviour

DEFF Research Database (Denmark)

Legarth, Brian Nyvang; Tvergaard, Viggo; Kuroda, Mitsutoshi

2002-01-01

For a crack in a homogeneous material the effect of plastic anisotropy on crack-tip blunting and on the near-tip stress and strain fields is analyzed numerically. The full finite strain analyses are carried out for plane strain under small scale yielding conditions, with purely symmetric mode I...... loading remote from the crack-tip. In cases where the principal axes of the anisotropy are inclined to the plane of the crack it is found that the plastic zones as well as the stress and strain fields just around the blunted tip of the crack become non-symmetric. In these cases the peak strain...... on the blunted tip occurs off the center line of the crack, thus indicating that the crack may want to grow in a different direction. When the anisotropic axes are parallel to the crack symmetry is retained, but the plastic zones and the near-tip fields still differ from those predicted by standard isotropic...

Asymptotic techniques in elastic-plastic analysis of structures

International Nuclear Information System (INIS)

Sayir, M.

1983-01-01

Elastic-plastic structures can nowadays be analyzed with the powerful numerical procedures of the finite element method. Nevertheless, in many engineering applications, analytical expressions capable of predicting with sufficient accuracy the stress distributions, the extent of the plastic zones and the load displacement behaviour could be of great practical value. For simple structures and loading stages not too far from the elastic limit, such analytical expressions may be obtained by using perturbation methods and asymptotic expansions. A small dimensionless parameter epsilon is defined as the ratio of a length characterizing the extent of the narrow plastic zone, to a conveniently chosen typical dimension of the structure. Stresses and displacements are formally expanded as asymptotic series in terms of powers of epsilon. For each order of magnitude, the exact basic relations lead to a separate set of simplified differential equations which can be integrated analytically or numerically by using standard procedures. The method is very general and can be applied to several classes of plastic behaviour and of structural problems. Three examples of very simple structures are chosen in particular to illustrate the applicability of the perturbation method to engineering problems. (orig./RW)

Can plastic mulching replace irrigation in dryland agriculture?

Science.gov (United States)

Wang, L.; Daryanto, S.; Jacinthe, P. A.

2017-12-01

Increasing water use efficiency (WUE) is a key strategy to maintaining crops yield without over-exploiting the scarce water resource. Plastic mulching technology for wheat and maize has been commonly used in China, but their effect on yield, soil moisture, evapotranspiration (ET), and WUE has not been compared with traditional irrigation method. Using a meta-analysis approach, we quantitatively examined the efficacy of plastic mulching in comparison with traditional irrigation in dryland agriculture. Our results showed that plastic mulching technique resulted in yield increase comparable to irrigated crops but used 24% less water. By covering the ridges with plastic and channeling rainwater into a very narrow planting zone (furrow), plastic mulching increased WUE and available soil moisture. Higher WUE in plastic-mulched croplands was likely a result of greater proportion of available water being used for transpiration than evaporation. If problems related to production costs and residual plastic pollution could be managed, plastic mulching technology would become a promising strategy for dryland farming in other regions.

Translation-rotation plasticity as basic mechanism of plastic deformation in macro-, micro- and nanoindentation processes

International Nuclear Information System (INIS)

Grabco, D; Shikimaka, O; Harea, E

2008-01-01

This paper presents a brief review of multilateral examinations for the purpose of detection of interrelation between processes occuring in solids at different levels of action of exterior loading, namely, at macro-, micro- and nanoindentation. Convincing arguments supporting the rotation deformation mechanism alongside the recognized dislocation one are adduced. It has been shown that the decrease in dislocation mobility leads at all scales to the intensification of rotation plasticity and to the involvement of other plastic deformation mechanisms, such as appearance and interaction of disclinations, twinning, phase transition and compression of material. The conversion from translation plasticity to the rotation-translation one means transition to the higher level of plastic deformation, the mesolevel, when the possibilities of the previous microscopic level are exhausted. It was established that the plastic deformation zone in the vicinity of indentations could be separated into two main specific regions: (i) peripheral region predominantly with the dislocation deformation mechanism; otherwise, translation mechanism: microlevel, and (ii) quasidestructured region mainly with the disclination or the intergranular sliding mechanism: rotation mechanism, mesolevel

Parametric analysis of plastic strain and force distribution in single pass metal spinning

International Nuclear Information System (INIS)

Choudhary, Shashank; Tejesh, Chiruvolu Mohan; Regalla, Srinivasa Prakash; Suresh, Kurra

2013-01-01

Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India

Parametric analysis of plastic strain and force distribution in single pass metal spinning

Science.gov (United States)

Choudhary, Shashank; Tejesh, Chiruvolu Mohan; Regalla, Srinivasa Prakash; Suresh, Kurra

2013-12-01

Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India.

Parametric analysis of plastic strain and force distribution in single pass metal spinning

Energy Technology Data Exchange (ETDEWEB)

Choudhary, Shashank, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Tejesh, Chiruvolu Mohan, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Regalla, Srinivasa Prakash, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Suresh, Kurra, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in [Department of Mechanical Engineering, BITS-Pilani, Hyderabad Campus, Shamirpet, Hyderabad, 500078, Andhra Pradesh (India)

2013-12-16

Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India.

The impact of animation on the length of stay and radius of movement of the excursion-recreational tourism

Directory of Open Access Journals (Sweden)

Dimitrić Dragana

2016-01-01

Full Text Available The basic hypothesis from which we started in the paper is the claim that animation of visitors has a direct impact on the length and radius of excursion-recreational tourism. The main objective of the research is to define the role of animation in the choice of tourist destination and length of staying. In the area of the City of Belgrade, there are more protected natural areas and one of them is the Great War Island located at the confluence of the River Sava in River Danube. This area has three protected zones. Temporary population that was the subject of the interview, as well as the Association of Tourist Guides of Serbia occupate one of these zones. We concluded that one of the biggest advantages of developing tourism of the Great War Island is the possibility of developing certain forms of tourism, and one of these forms, the excursion-recreational tourism has multiple positive effects on the population. The paper concluded that the animation proportionally affects the length of stay of tourists, as well as the radius of their movement.

Plastic debris in the open ocean

KAUST Repository

Cozar, Andres

2014-06-30

There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean.

Plastic debris in the open ocean.

Science.gov (United States)

Cózar, Andrés; Echevarría, Fidel; González-Gordillo, J Ignacio; Irigoien, Xabier; Ubeda, Bárbara; Hernández-León, Santiago; Palma, Alvaro T; Navarro, Sandra; García-de-Lomas, Juan; Ruiz, Andrea; Fernández-de-Puelles, María L; Duarte, Carlos M

2014-07-15

There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean.

Plastic debris in the open ocean

Science.gov (United States)

Cózar, Andrés; Echevarría, Fidel; González-Gordillo, J. Ignacio; Irigoien, Xabier; Úbeda, Bárbara; Hernández-León, Santiago; Palma, Álvaro T.; Navarro, Sandra; García-de-Lomas, Juan; Ruiz, Andrea; Fernández-de-Puelles, María L.; Duarte, Carlos M.

2014-01-01

There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean. PMID:24982135

Marine plastic pollution in waters around Australia: characteristics, concentrations, and pathways

OpenAIRE

Reisser, Julia Wiener; Shaw, Jeremy; Wilcox, Chris; Hardesty, Britta Denise; Proietti, Maíra Carneiro; Thums, Michele; Pattiaratchi, Charitha

2013-01-01

Plastics represent the vast majority of human-made debris present in the oceans. However, their characteristics, accumulation zones, and transport pathways remain poorly assessed. We characterised and estimated the concentration of marine plastics in waters around Australia using surface net tows, and inferred their potential pathways using particle-tracking models and real drifter trajectories. The 839 marine plastics recorded were predominantly small fragments ("microplastics", median lengt...

Effect of plastic strain on elastic-plastic fracture toughness of SM490 carbon steel. Assessment by stress-based criterion for ductile crack initiation

International Nuclear Information System (INIS)

Kamaya, Masayuki

2012-01-01

Although the plastic strain induced in materials increases the mechanical strength, it may reduce the fracture toughness. In this study, the change in fracture toughness of SM490 carbon steel due to pre-straining was investigated using a stress-based criterion for ductile crack initiation. The specimens with blunt notch of various radiuses were used in addition to those with conventional fatigue pre-cracking. The degree of applied plastic strain was 5%, 10% or 20%. The fracture toughness was largest when the induced plastic strain was 5%, although it decreased for the plastic strains of 10% and 20%. The stress and strain distributions near the crack tip of fracture toughness test specimens was investigated by elastic-plastic finite element analyses using a well-correlated stress-strain curve for large strain. It was shown that the critical condition at the onset of the ductile crack was better correlated with the equivalent stress than the plastic strain at the crack tip. By using the stress-based criterion, which was represented by the equivalent stress and stress triaxiality, the change in the fracture toughness due to pre-straining could be reasonably explained. Based on these results, it was concluded that the stress-based criterion should be used for predicting the ductile crack initiation. (author)

Impacts of macro - and microplastic on macrozoobenthos abundance in intertidal zone

Science.gov (United States)

Bangun, A. P.; Wahyuningsih, H.; Muhtadi, A.

2018-02-01

Plastics pollution in coastal areas is one of the topics that have received more attention over the past few years. The intertidal zone is a waters area that is directly affected by contamination of plastic waste from land and sea. The purpose of this study was to analyze the types and abundance of plastic waste in the intertidal zone and its impact on macrozoobenthos abundance. This research was conducted at Pesisir Desa Jaring Halus in February-April 2017. Macrozoobenthos and macro - micro plastic were collected by using quadratic transect. Sediments were collected with a core, to a depth of 30 cm. Microplastic and macroplastic abundances were analyzed using separation of sediment density and hand sorting. The dominant micro plastic types were film (52.30%), fiber (24.88%), fragments (22.74%), followed by pellets (0.1%). The total number of microplastics were 326,33 items and macro plastic were 308 items. Macroplastic abundance is positively correlated with microplastic (0.765). The abundance of macrozoobenthos is negatively correlated with microplastic abundance (-0.368) and with macro plastic abundance (-0.633). The management strategies were suggested clean up marine debris, decrease plastic using and built up the station of debris processing.

Linear intra-bone geometry dependencies of the radius: Radius length determination by maximum distal width

International Nuclear Information System (INIS)

Baumbach, S.F.; Krusche-Mandl, I.; Huf, W.; Mall, G.; Fialka, C.

2012-01-01

Purpose: The aim of the study was to investigate possible linear intra-bone geometry dependencies by determining the relation between the maximum radius length and maximum distal width in two independent populations and test for possible gender or age effects. A strong correlation can help develop more representative fracture models and osteosynthetic devices as well as aid gender and height estimation in anthropologic/forensic cases. Methods: First, maximum radius length and distal width of 100 consecutive patients, aged 20–70 years, were digitally measured on standard lower arm radiographs by two independent investigators. Second, the same measurements were performed ex vivo on a second cohort, 135 isolated, formalin fixed radii. Standard descriptive statistics as well as correlations were calculated and possible gender age influences tested for both populations separately. Results: The radiographic dataset resulted in a correlation of radius length and width of r = 0.753 (adj. R 2 = 0.563, p 2 = 0.592) and side no influence on the correlation. Radius length–width correlation for the isolated radii was r = 0.621 (adj. R 2 = 0.381, p 2 = 0.598). Conclusion: A relatively strong radius length–distal width correlation was found in two different populations, indicating that linear body proportions might not only apply to body height and axial length measurements of long bones but also to proportional dependency of bone shapes in general.

Microplastic-associated Bacterial Assemblages in the Intertidal Zone

Science.gov (United States)

Jiang, P.; Zhao, S.; Zhu, L.; Li, D.

2017-12-01

Plastic debris is posing a planetary-scale threat. As a zone where terrestrial and marine ecosystems interactions occur, the accumulation of plastic marine debris (PMD) in intertidal environments has been well documented. But the information of plastic-associated microbial community (the "Plastisphere") in the intertidal zone is scanty. Utilizing the high-throughput sequencing, we profiled the bacterial communities attached to microplastic samples from the intertidal locations around Yangtze estuary. The structure and composition of Plastisphere communities in current study varied significantly with geographical stations. The taxonomic composition on microplastic samples implied their sedimental and aquatic origins. Some members of hydrocarbon degrading microorganisms and potential pathogens were detected on microplastic. Overall, our findings fuel the evidence for the occurrence of diverse microbial assemblages on PMD and improving our understanding of Plastisphere ecology, which could support the management action and policy change related to PMD.

Short-time home coming project in evacuation zone

International Nuclear Information System (INIS)

Tatsuzaki, Hideo

2011-01-01

Accident at Fukushima Daiichi Nuclear Power Plants (NPPs) forced neighboring residents to evacuate, and evacuation zone (20 km radius from NPPs) was defined as highly contaminated and designated as no-entry zones. Residents had been obliged to live a refugee life for a longer period than expected. Short-time home coming project was initiated according to their requests. They came to the meeting place called transfer place (20 - 30 km radius from NPPs), wore protective clothing and personal dosimeter with having drinking water and came home in evacuation zone with staffs by bus. Their healthcare management professionals were fully prepared for emergency. After collecting necessary articles at home within two hours, they returned to the meeting place by bus for screening and dressing, and went back to refuge house. If screening data were greater than 13 kcpm using GM counters, partial body decontamination had been conducted by wiping and if greater than 100 kcpm, whole body decontamination was requested but not conducted. Dose rate of residents and staffs was controlled less than 1 mSv, which was alarm level of personal dosimeter. Stable iodine was prepared but actually not used. (T. Tanaka)

Elastic-plastic collapse of super-elastic shock waves in face-centered-cubic solids

International Nuclear Information System (INIS)

Zhakhovsky, Vasily V; Demaske, Brian J; Oleynik, Ivan I; Inogamov, Nail A; White, Carter T

2014-01-01

Shock waves in the [110] and [111] directions of single-crystal Al samples were studied using molecular dynamics (MD) simulations. Piston-driven simulations were performed to investigate the split shock-wave regime. At low piston velocities, the material is compressed initially to a metastable over-compressed elastic state leading to a super-elastic single shock wave. This metastable elastic state later collapses to a plastic state resulting in the formation of a two-wave structure consisting of an elastic precursor followed by a slower plastic wave. The single two-zone elastic-plastic shock-wave regime appearing at higher piston velocities was studied using moving window MD. The plastic wave attains the same average speed as the elastic precursor to form a single two-zone shock wave. In this case, repeated collapse of the highly over-compressed elastic state near the plastic shock front produces ultrashort triangle pulses that provide the pressure support for the leading elastic precursor.

Spectral radius of graphs

CERN Document Server

Stevanovic, Dragan

2015-01-01

Spectral Radius of Graphs provides a thorough overview of important results on the spectral radius of adjacency matrix of graphs that have appeared in the literature in the preceding ten years, most of them with proofs, and including some previously unpublished results of the author. The primer begins with a brief classical review, in order to provide the reader with a foundation for the subsequent chapters. Topics covered include spectral decomposition, the Perron-Frobenius theorem, the Rayleigh quotient, the Weyl inequalities, and the Interlacing theorem. From this introduction, the

Elastic-plastic fracture mechanics study of thermal shock cracking

International Nuclear Information System (INIS)

Hirano, K.; Kobayashi, H.; Nakazawa, H.

1980-01-01

This paper describes thermal shock experiments conducted on a nuclear pressure vessel steel (A533 Grade B Class 1), an AISI304 steel and a tool steel (JIS SKD62) using both a new thermal shock test facility and method. Analysis of their quasi-static thermal stress intensity factors is performed on the basis of linear-elastic fracture mechanics; and a thermal shock fracture toughness value, Ksub(tsc) is evaluated. Then elastic-plastic fracture toughness tests are carried out in the same high temperature range of the thermal shock experiment, and a relation between the stretched zone width, SZW, formed as a result of the fatigue precrack tip plastic blunting and the J-integral is clarified. An elastic-plastic thermal shock fracture toughness value, Jsub(tsc), is evaluated from a critical value of the stretched zone width, SZWsub(tsc), at the initiation of the thermal shock cracking by using the relation between SZW and J. The Jsub(tsc) value is compared with an elastic-plastic fracture toughness value, Jsub(Ic), and the difference between these Jsub(tsc) and Jsub(Ic) values is discussed on the basis of fractography. (author)

radioactive survey on the contact zone (paleogene - neogene) in Ad-Daww basin of Syria, using alpha sensitive plastic film technique

International Nuclear Information System (INIS)

Mouty, M.; Al-Hilal, M.; Kattaa, B.

1995-01-01

A detailed radon survey has been carried out over the contact zone of marine Paleogene and continental Neogene Formations in Ad-Daww basin (Central Syria), for the purpose of uranium exploration. Radon measurements were performed in a grid pattern using alpha sensitive plastic film technique, type 1B CN-85. Radon concentrations in soil were monitored across the aforementioned zone for 1.5 year, from April 93 to July 94, and their average has been calculated. Alpha Track density was found to be varying from 81 to 227 T/mm2 in Qarytein station, 65 to 124 T/mm2 in Bardeh station and 101 to 196 T/mm2 in Tyas station. The results of this work showed that the anomalous radon values were found to be corresponded to the Oligocene-Miocene geological surface in the study area. These relatively high values are most likely related to scattered uranium mineralization precipitated on surface along a chemically reducing zone where surface water of terrestrial and marine origin intermingled. A comparison between gamma count rate and trak etch density revealed a fairly good correlation, which indicates that the uranium occurrences on the geological contact (Oli - Mio) in Ad-Daww basin are of surficial nature. However, this may give a preliminary indication of probable subsurface extension of these occurrences preserved at depth away from surfacial weathering. (author). 6 refs., 2 tabs

Plastic pollution in the South Pacific subtropical gyre.

Science.gov (United States)

Eriksen, Marcus; Maximenko, Nikolai; Thiel, Martin; Cummins, Anna; Lattin, Gwen; Wilson, Stiv; Hafner, Jan; Zellers, Ann; Rifman, Samuel

2013-03-15

Plastic marine pollution in the open ocean of the southern hemisphere is largely undocumented. Here, we report the result of a (4489 km) 2424 nautical mile transect through the South Pacific subtropical gyre, carried out in March-April 2011. Neuston samples were collected at 48 sites, averaging 50 nautical miles apart, using a manta trawl lined with a 333 μm mesh. The transect bisected a predicted accumulation zone associated with the convergence of surface currents, driven by local winds. The results show an increase in surface abundance of plastic pollution as we neared the center and decrease as we moved away, verifying the presence of a garbage patch. The average abundance and mass was 26,898 particles km(-2) and 70.96 g km(-2), respectively. 88.8% of the plastic pollution was found in the middle third of the samples with the highest value of 396,342 particles km(-2) occurring near the center of the predicted accumulation zone. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simulations of a stretching bar using a plasticity model from the shear transformation zone theory

Energy Technology Data Exchange (ETDEWEB)

Rycroft, Chris H.; Gibou, Frederic

2010-06-05

An Eulerian simulation is developed to study an elastoplastic model of amorphous materials that is based upon the shear transformation zone theory developed by Langer and coworkers. In this theory, plastic deformation is controlled by an effective temperature that measures the amount of configurational disorder in the material. The simulation is used to model ductile fracture in a stretching bar that initially contains a small notch, and the effects of many of the model parameters are examined. The simulation tracks the shape of the bar using the level set method. Within the bar, a finite difference discretization is employed that makes use of the essentially non-oscillatory (ENO) scheme. The system of equations is moderately stiff due to the presence of large elastic constants, and one of the key numerical challenges is to accurately track the level set and construct extrapolated field values for use in boundary conditions. A new approach to field extrapolation is discussed that is second order accurate and requires a constant amount of work per gridpoint.

The proton radius puzzle

Science.gov (United States)

Bonesini, Maurizio

2017-12-01

The FAMU (Fisica degli Atomi Muonici) experiment has the goal to measure precisely the proton Zemach radius, thus contributing to the solution of the so-called proton radius "puzzle". To this aim, it makes use of a high-intensity pulsed muon beam at RIKEN-RAL impinging on a cryogenic hydrogen target with an high-Z gas admixture and a tunable mid-IR high power laser, to measure the hyperfine (HFS) splitting of the 1S state of the muonic hydrogen. From the value of the exciting laser frequency, the energy of the HFS transition may be derived with high precision ( 10-5) and thus, via QED calculations, the Zemach radius of the proton. The experimental apparatus includes a precise fiber-SiPMT beam hodoscope and a crown of eight LaBr3 crystals and a few HPGe detectors for detection of the emitted characteristic X-rays. Preliminary runs to optimize the gas target filling and its operating conditions have been taken in 2014 and 2015-2016. The final run, with the pump laser to drive the HFS transition, is expected in 2018.

TERRESTRIAL, HABITABLE-ZONE EXOPLANET FREQUENCY FROM KEPLER

International Nuclear Information System (INIS)

Traub, Wesley A.

2012-01-01

Data from Kepler's first 136 days of operation are analyzed to determine the distribution of exoplanets with respect to radius, period, and host-star spectral type. The analysis is extrapolated to estimate the percentage of terrestrial, habitable-zone (HZ) exoplanets. The Kepler census is assumed to be complete for bright stars (magnitude 0.5 Earth radius and periods β–1 , with β ≅ 0.71 ± 0.08; and an extrapolation to longer periods gives the frequency of terrestrial planets in the HZs of FGK stars as η ⊕ ≅ (34 ± 14)%. Thus about one-third of FGK stars are predicted to have at least one terrestrial, HZ planet.

Phase-field modelling of ductile fracture: a variational gradient-extended plasticity-damage theory and its micromorphic regularization.

Science.gov (United States)

Miehe, C; Teichtmeister, S; Aldakheel, F

2016-04-28

This work outlines a novel variational-based theory for the phase-field modelling of ductile fracture in elastic-plastic solids undergoing large strains. The phase-field approach regularizes sharp crack surfaces within a pure continuum setting by a specific gradient damage modelling. It is linked to a formulation of gradient plasticity at finite strains. The framework includes two independent length scales which regularize both the plastic response as well as the crack discontinuities. This ensures that the damage zones of ductile fracture are inside of plastic zones, and guarantees on the computational side a mesh objectivity in post-critical ranges. © 2016 The Author(s).

Plastic deformation of tubular crystals by dislocation glide.

Science.gov (United States)

Beller, Daniel A; Nelson, David R

2016-09-01

Tubular crystals, two-dimensional lattices wrapped into cylindrical topologies, arise in many contexts, including botany and biofilaments, and in physical systems such as carbon nanotubes. The geometrical principles of botanical phyllotaxis, describing the spiral packings on cylinders commonly found in nature, have found application in all these systems. Several recent studies have examined defects in tubular crystals associated with crystalline packings that must accommodate a fixed tube radius. Here we study the mechanics of tubular crystals with variable tube radius, with dislocations interposed between regions of different phyllotactic packings. Unbinding and separation of dislocation pairs with equal and opposite Burgers vectors allow the growth of one phyllotactic domain at the expense of another. In particular, glide separation of dislocations offers a low-energy mode for plastic deformations of solid tubes in response to external stresses, reconfiguring the lattice step by step. Through theory and simulation, we examine how the tube's radius and helicity affects, and is in turn altered by, the mechanics of dislocation glide. We also discuss how a sufficiently strong bending rigidity can alter or arrest the deformations of tubes with small radii.

Elasto-plastic model for transversely isotropic Tournemire shale based on microstructure approach

International Nuclear Information System (INIS)

Abdi, H.; Evgin, E.; Fall, M.; Nguyen, T.S.; Labrie, D.; Barnichon, J.D.; Su, G.; Simon, R.

2012-01-01

Document available in extended abstract form only. Argillaceous formations being considered as potential host rocks for the geological disposal of nuclear wastes are usually characterized by the presence of bedding planes, resulting in anisotropy of their strength and deformation properties. A laboratory program of uniaxial tests, triaxial tests, cyclic tests, and Brazilian tests with concurrent monitoring of acoustic emission was performed in order to determine the above properties. The experimental results and their interpretation are presented in detail in a companion paper (Abdi et al., 2012, in these proceedings). Typical results from triaxial tests indicate the following behaviour: 1. There is a strong dependence of the stress-strain behaviour with the loading orientation with respect to the bedding planes. 2. There are four distinct zones of the stress strain curve: a crack and/or bedding closure zone; an elastic zone, a plastic zone with strain hardening, and a collapse zone after the peak that leads abruptly to a residual strength value. 3. There is damage, especially after the peak, resulting in the degradation of the stiffness as shown by unloading-reloading cycles. In order to reproduce the above behaviour, we adopted a classical elasto-plastic framework. In the elastic range, the transversely isotropic nature of the material is taken into account by the adoption of an elastic stiffness matrix that requires five independent elastic constants. These elastic constants show degradation with the accumulated damage. Using the deviatoric plastic strain as a measure of damage, we expressed functional relationships for these constants, using the results of cyclic triaxial tests. For the plastic behaviour, we used a Mohr-Coulomb yield criterion which takes into account the relative orientation of the applied stress and the bedding planes, and also strain hardening and softening. In this work we used the deviatoric plastic strain as the hardening parameter in

Critical cladding radius for hybrid cladding modes

Science.gov (United States)

Guyard, Romain; Leduc, Dominique; Lupi, Cyril; Lecieux, Yann

2018-05-01

In this article we explore some properties of the cladding modes guided by a step-index optical fiber. We show that the hybrid modes can be grouped by pairs and that it exists a critical cladding radius for which the modes of a pair share the same electromagnetic structure. We propose a robust method to determine the critical cladding radius and use it to perform a statistical study on the influence of the characteristics of the fiber on the critical cladding radius. Finally we show the importance of the critical cladding radius with respect to the coupling coefficient between the core mode and the cladding modes inside a long period grating.

Effect of perturbation of convective energy transport on the luminosity and radius of the sun

International Nuclear Information System (INIS)

Endal, A.S.; Twigg, L.W.

1982-01-01

The response of solar models to perturbations of the efficiency of convective energy transport is studied for a number of cases. Such perturbations primarily affect the shallow superadiabatic layer of the convective envelope (at depths 3 km below the photosphere). Independent of the details of the perturbation scheme, the resulting change in the solar radius (ΔR/R) is always very small compared to the change in luminosity (ΔL/L). This appears to be true for any physical mechanism of solar variability which operates in the outer layers of the convection zone. Changes of the solar radius have been inferred by Dunham et al. from historical observations of solar eclipses in 1715 and 1925. Considering the constraints on concurrent luminosity changes, this type of solar variability must be indicative of changes in the solar structure at substantial depths below the superadiabatic layer of the convective envelope

An iterative algorithm for calculating stylus radius unambiguously

International Nuclear Information System (INIS)

Vorburger, T V; Zheng, A; Renegar, T B; Song, J-F; Ma, L

2011-01-01

The stylus radius is an important specification for stylus instruments and is commonly provided by instrument manufacturers. However, it is difficult to measure the stylus radius unambiguously. Accurate profiles of the stylus tip may be obtained by profiling over an object sharper than itself, such as a razor blade. However, the stylus profile thus obtained is a partial arc, and unless the shape of the stylus tip is a perfect sphere or circle, the effective value of the radius depends on the length of the tip profile over which the radius is determined. We have developed an iterative, least squares algorithm aimed to determine the effective least squares stylus radius unambiguously. So far, the algorithm converges to reasonable results for the least squares stylus radius. We suggest that the algorithm be considered for adoption in documentary standards describing the properties of stylus instruments.

Numerical studies of cavitation erosion on an elastic-plastic material caused by shock-induced bubble collapse

Science.gov (United States)

Turangan, C. K.; Ball, G. J.; Jamaluddin, A. R.; Leighton, T. G.

2017-09-01

We present a study of shock-induced collapse of single bubbles near/attached to an elastic-plastic solid using the free-Lagrange method, which forms the latest part of our shock-induced collapse studies. We simulated the collapse of 40 μm radius single bubbles near/attached to rigid and aluminium walls by a 60 MPa lithotripter shock for various scenarios based on bubble-wall separations, and the collapse of a 255 μm radius bubble attached to aluminium foil with a 65 MPa lithotripter shock. The coupling of the multi-phases, compressibility, axisymmetric geometry and elastic-plastic material model within a single solver has enabled us to examine the impingement of high-speed liquid jets from the shock-induced collapsing bubbles, which imposes an extreme compression in the aluminium that leads to pitting and plastic deformation. For certain scenarios, instead of the high-speed jet, a radially inwards flow along the aluminium surface contracts the bubble to produce a `mushroom shape'. This work provides methods for quantifying which parameters (e.g. bubble sizes and separations from the solid) might promote or inhibit erosion on solid surfaces.

The brittle-viscous-plastic evolution of shear bands in the South Armorican Shear Zone

Science.gov (United States)

Bukovská, Zita; Jeřábek, Petr; Morales, Luiz F. G.; Lexa, Ondrej; Milke, Ralf

2014-05-01

microcracks and nearly absent in matrix grains in the well developed C bands. The chemical variation between primary and secondary new-formed micas was clearly identified by the Mg-Ti-Na content. The microstructural analysis documents a progressive decrease in quartz grain size and increasing interconnectivity of K-feldspar and white mica towards more mature shear bands. The contact-frequency analysis demonstrates that the phase distribution in shear bands tends to evolve from quartz aggregate distribution via randomization to K-feldspar aggregate distribution. The boundary preferred orientation is absent in quartz-quartz contacts either inside of outside the C bands, while it changes from random to parallel to the C band for the K-feldspar and and K-feldspar-quartz boundaries. The lack of crystallographic preferred orientation of the individual phases in the mixed matrix of the C planes suggests a dominant diffusion-assisted grain boundary sliding deformation mechanism. In the later stages of shear band development, the deformation is accommodated by crystal plasticity of white mica in micaceous bands. The crystallographic and microstructural data thus indicate two important switches in deformation mechanisms, from (i) brittle to Newtonian viscous behavior in the initial stages of shear band evolution and from (ii) Newtonian viscous to power law in the later evolutionary stages. The evolution of shear bands in the South Armorican Shear Zone thus document the interplay between deformation mechanisms and chemical reactions in deformed granitoids.

Two Back Stress Hardening Models in Rate Independent Rigid Plastic Deformation

Science.gov (United States)

Yun, Su-Jin

In the present work, the constitutive relations based on the combination of two back stresses are developed using the Armstrong-Frederick, Phillips and Ziegler’s type hardening rules. Various evolutions of the kinematic hardening parameter can be obtained by means of a simple combination of back stress rate using the rule of mixtures. Thus, a wide range of plastic deformation behavior can be depicted depending on the dominant back stress evolution. The ultimate back stress is also determined for the present combined kinematic hardening models. Since a kinematic hardening rule is assumed in the finite deformation regime, the stress rate is co-rotated with respect to the spin of substructure obtained by incorporating the plastic spin concept. A comparison of the various co-rotational rates is also included. Assuming rigid plasticity, the continuum body consists of the elastic deformation zone and the plastic deformation zone to form a hybrid finite element formulation. Then, the plastic deformation behavior is investigated under various loading conditions with an assumption of the J2 deformation theory. The plastic deformation localization turns out to be strongly dependent on the description of back stress evolution and its associated hardening parameters. The analysis for the shear deformation with fixed boundaries is carried out to examine the deformation localization behavior and the evolution of state variables.

On the proton radius problem

OpenAIRE

Giannini, M. M.; Santopinto, E.

2013-01-01

The recent values of the proton charge radius obtained by means of muonic-hydrogen laser spectroscopy are about $4\\%$ different from the electron scattering data. It has been suggested that the proton radius is actually measured in different frames and that, starting from a non relativistic quark model calculation, the Lorentz transformation of the form factors accounts properly for the discepancy. We shall show that the relation between the charge radii measured in different frames can be de...

Understanding the mass-radius relation for sub-Neptunes: radius as a proxy for composition

Energy Technology Data Exchange (ETDEWEB)

Lopez, Eric D.; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

2014-09-01

Transiting planet surveys like Kepler have provided a wealth of information on the distribution of planetary radii, particularly for the new populations of super-Earth- and sub-Neptune-sized planets. In order to aid in the physical interpretation of these radii, we compute model radii for low-mass rocky planets with hydrogen-helium envelopes. We provide model radii for planets 1-20 M {sub ⊕}, with envelope fractions 0.01%-20%, levels of irradiation 0.1-1000 times Earth's, and ages from 100 Myr to 10 Gyr. In addition we provide simple analytic fits that summarize how radius depends on each of these parameters. Most importantly, we show that at fixed H/He envelope fraction, radii show little dependence on mass for planets with more than ∼1% of their mass in their envelope. Consequently, planetary radius is to a first order a proxy for planetary composition, i.e., H/He envelope fraction, for Neptune- and sub-Neptune-sized planets. We recast the observed mass-radius relationship as a mass-composition relationship and discuss it in light of traditional core accretion theory. We discuss the transition from rocky super-Earths to sub-Neptune planets with large volatile envelopes. We suggest ∼1.75 R {sub ⊕} as a physically motivated dividing line between these two populations of planets. Finally, we discuss these results in light of the observed radius occurrence distribution found by Kepler.

Recombination radius of a Frenkel pair and capture radius of a self-interstitial atom by vacancy clusters in bcc Fe

International Nuclear Information System (INIS)

Nakashima, Kenichi; Stoller, Roger E; Xu, Haixuan

2015-01-01

The recombination radius of a Frenkel pair is a fundamental parameter for the object kinetic Monte Carlo (OKMC) and mean field rate theory (RT) methods that are used to investigate irradiation damage accumulation in irradiated materials. The recombination radius in bcc Fe has been studied both experimentally and numerically, however there is no general consensus about its value. The detailed atomistic processes of recombination also remain uncertain. Values from 1.0a 0 to 3.3a 0 have been employed as a recombination radius in previous studies using OKMC and RT. The recombination process of a Frenkel pair is investigated at the atomic level using the self-evolved atomistic kinetic Monte Carlo (SEAKMC) method in this paper. SEAKMC calculations reveal that a self-interstitial atom recombines with a vacancy in a spontaneous reaction from several nearby sites following characteristic pathways. The recombination radius of a Frenkel pair is estimated to be 2.26a 0 by taking the average of the recombination distances from 80 simulation cases. In addition, we apply these procedures to the capture radius of a self-interstitial atom by a vacancy cluster. The capture radius is found to gradually increase with the size of the vacancy cluster. The fitting curve for the capture radius is obtained as a function of the number of vacancies in the cluster. (paper)

Pixels Intensity Evolution to Describe the Plastic Films Deformation

Directory of Open Access Journals (Sweden)

Juan C. Briñez-De León

2013-11-01

Full Text Available This work proposes an approach for mechanical behavior description in the plastic film deformation using techniques for the images analysis, which are based on the intensities evolution of fixed pixels applied to an images sequence acquired through polarizing optical assembly implemented around the platform of the plastic film deformation. The pixels intensities evolution graphs, and mechanical behavior graphic of the deformation has dynamic behaviors zones which could be associated together.

Sub-micron indent induced plastic deformation in copper and irradiated steel

International Nuclear Information System (INIS)

Robertson, Ch.

1998-09-01

In this work we aim to study the indent induced plastic deformation. For this purpose, we have developed a new approach, whereby the indentation curves provides the mechanical behaviour, while the deformation mechanisms are observed thanks to Transmission Electron Microscopy (TEM). In order to better understand how an indent induced dislocation microstructure forms, numerical modeling of the indentation process at the scale of discrete dislocations has been worked out as well. Validation of this modeling has been performed through direct comparison of the computed microstructures with TEM micrographs of actual indents in pure Cu [001]. Irradiation induced modifications of mechanical behaviour of ion irradiated 316L have been investigated, thanks to the mentioned approach. An important hardening effect was reported from indentation data (about 50%), on helium irradiated 316L steel. TEM observations of the damage zone clearly show that this behaviour is associated with the presence of He bubbles. TEM observations of the indent induced plastic zone also showed that the extent of the plastic zone is strongly correlated with hardness, that is to say: harder materials gets a smaller plastic zone. These results thus clearly established that the selected procedure can reveal any irradiation induced hardening in sub-micron thick ion irradiated layers. The behaviour of krypton irradiated 316L steel is somewhat more puzzling. In one hand indeed, a strong correlation between the defect cluster size and densities on the irradiation temperature is observed in the 350 deg C -600 deg C range, thanks to TEM observations of the damage zone. On the other hand, irradiation induced hardening reported from indentation data is relatively small (about 10%) and shows no dependence upon the irradiation temperature (within the mentioned range). In addition, it has been shown that the reported hardening vanishes following appropriate post-irradiation annealing, although most of the TEM

Taylor-plasticity-based analysis of length scale effects in void growth

KAUST Repository

Liu, Junxian

2014-09-25

We have studied the void growth problem by employing the Taylor-based strain gradient plasticity theories, from which we have chosen the following three, namely, the mechanism-based strain gradient (MSG) plasticity (Gao et al 1999 J. Mech. Phys. Solids 47 1239, Huang et al 2000 J. Mech. Phys. Solids 48 99-128), the Taylor-based nonlocal theory (TNT; 2001 Gao and Huang 2001 Int. J. Solids Struct. 38 2615) and the conventional theory of MSG (CMSG; Huang et al 2004 Int. J. Plast. 20 753). We have addressed the following three issues which occur when plastic deformation at the void surface is unconstrained. (1) Effects of elastic deformation. Elasticity is essential for cavitation instability. It is therefore important to guarantee that the gradient term entering the Taylor model is the effective plastic strain gradient instead of the total strain gradient. We propose a simple elastic-plastic decomposition method. When the void size approaches the minimum allowable initial void size related to the maximum allowable geometrically necessary dislocation density, overestimation of the flow stress due to the negligence of the elastic strain gradient is on the order of lεY/R0 near the void surface, where l, εY and R0 are, respectively, the intrinsic material length scale, the yield strain and the initial void radius. (2) MSG intrinsic inconsistency, which was initially mentioned in Gao et al (1999 J. Mech. Phys. Solids 47 1239) but has not been the topic of follow-up studies. We realize that MSG higher-order stress arises due to the linear-strain-field approximation within the mesoscale cell with a nonzero size, lε. Simple analysis shows that within an MSG mesoscale cell near the void surface, the difference between microscale and mesoscale strains is on the order of (lε/R0)2, indicating that when lε/R0 ∼ 1.0, the higher-order stress effect can make the MSG result considerably different from the TNT or CMSG results. (3) Critical condition for cavitation instability

Elastic-plastic Fracture Mechanics Assessment of nozzle corners submitted to thermal shock loading

International Nuclear Information System (INIS)

Chapuliot, S.; Marie, S.

2016-01-01

This paper focuses on the development of a simplified analytical scheme for the elastic-plastic Fracture Mechanics Assessment of large nozzle corners. Within that frame, following the specific numerical effort performed for the definition of a Stress Intensity Factor compendium, complementary elastic-plastic developments are proposed here for the consideration of the thermal shock loading in the elastic-plastic domain: this type of loading is a major loading for massive structures such as nozzle corners of large components. Thus, an important numerical was performed in order to extend the applicability domain of existing analytical schemes to those complex geometries. The final formulation is a simple one, applicable to a large variety of materials and geometrical configurations as long as the structure is large and the defect remains small in comparison to the internal radius of the nozzle. - Highlights: • Fracture Mechanics Assessment of large nozzle corners. • Elastic-plastic Stress Intensity Factor determination under thermal shock loading. • Semi-analytical schemes for J calculation.

Dose-dependent zoning of estranged territory after the Chernobyl power plant accident

International Nuclear Information System (INIS)

Savkin, M.N.

1994-01-01

The alienation zone was forming in May-September 1986 when the population was evacuated from the areas nearest to the Chernobyl power pilant. The presnet-day contour of the zone is a result of combination of a geographic criterion, a circular with a 30 km radius, and of radiation criteria developed at the earliest stages after the accident. The authors discuss dose-dependent regioning of the alienation zone at the latest stages of the accident and analyze radiation and hygienic aspects of possible reevacuation of the population

Analysis of temperature profiles and the mechanism of silicon substrate plastic deformation under epitaxial growth

International Nuclear Information System (INIS)

Mirkurbanov, H.A.; Sazhnev, S.V.; Timofeev, V.N.

2004-01-01

Full text: Thermal treatment of silicon wafers holds one of the major place in the manufacturing of semi-conductor devices. Thermal treatment includes wafer annealing, thermal oxidation, epitaxial growing etc. Quality of wafers in the high-temperature processes (900-1200 deg C) is estimated by the density of structural defects, including areas of plastic deformation, which are shown as the slip lines appearance. Such areas amount to 50-60 % of total wafer surface. The plastic deformation is caused by the thermal stresses. Experimental and theoretical researches allowed to determine thermal balance and to construct a temperature profiles throughout the plate surface. Thermal stresses are caused by temperature drop along the radius of a wafer and at the basic peripheral ring. The threshold temperature drop between center f a wafer and its peripherals (ΔT) for slip lines appearance, amounts to 15-17 deg. C. At the operating temperature of 900-1200 deg. C and ΔT>20 deg. C, the stresses reach the silicon yield point. According to the results of the researches of structure and stress profiles in a wafer, the mechanism of slip lines formation has been constructed. A source of dislocations is the rear broken layer of thickness 8-10 microns, formed after polishing. The micro-fissures with a density 10 5 -10 6 cm -2 are the sources of dislocations. Dislocations move on a surface of a wafer into a slip plane (111). On a wafer surface with orientation (111) it is possible to allocate zones where the tangential stress vector is most favorably directed with respect to a slip plane leaving on a surface, i.e. the shift stresses are maximal in the slip plane. The way to eliminate plastic deformation is to lower the temperature drop to a level of <15 deg. C and elimination of the broken layer in wafer

A Maximum Radius for Habitable Planets.

Science.gov (United States)

Alibert, Yann

2015-09-01

We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.

Laboratory test methods to determine the degradation of plastics in marine environmental conditions.

Science.gov (United States)

Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

2012-01-01

In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9 months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break = -66% in 2 years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment.

Laboratory Test Methods to Determine the Degradation of Plastics in Marine Environmental Conditions

Science.gov (United States)

Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

2012-01-01

In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9 months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break = −66% in 2 years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment. PMID:22737147

Laboratory test methods to determine the degradation of plastics in marine environmental conditions

Directory of Open Access Journals (Sweden)

Maurizio eTosin

2012-06-01

Full Text Available In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain. However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation. Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi was shown to degrade (total disintegration achieved in less than 9 months when buried in wet sand (simulation test of the tidal zone, to lose mechanical properties but still maintain integrity (tensile strength at break = -66% in 2 years when exposed to sea water in an aquarium (simulation of pelagic domain, and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88% when located at the sediment/sea water interface (simulation of benthic domain. This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment.

A library of prompt detonation reaction zone data

Energy Technology Data Exchange (ETDEWEB)

Souers, P. C., LLNL

1998-06-01

Tables are given listing literature data that allows calculation of sonic reaction zones at or near steady-state for promptly detonating explosive cylinders. The data covers homogeneous, heterogeneous, composite, inorganic and binary explosives and allows comparison across the entire explosive field. Table 1 lists detonation front curvatures. Table 2 lists Size Effect data, i.e. the change of detonation velocity with cylinder radius. Table 3 lists failure radii and detonation velocities. Table 4 lists explosive compositions. A total of 51 references dating back into the 1950`s are given. Calculated reaction zones, radii of curvature and growth rate coefficients are listed.

Coseismic microstructures of experimental fault zones in Carrara marble

Science.gov (United States)

Ree, Jin-Han; Ando, Jun-ichi; Han, Raehee; Shimamoto, Toshihiko

2014-09-01

Experimental fault zones developed in Carrara marble that were deformed at seismic slip rates (1.18-1.30 m s-1) using a high-velocity-rotary-shear apparatus exhibit very low friction (friction coefficient as low as 0.06) at steady state due to nanoparticle lubrication of the decomposition product (lime). The fault zones show a layered structure; a central slip-localization layer (5-60 μm thick) of lime nanograins mantled by gouge layers (5-150 μm thick) and a plastically deformed layer (45-500 μm thick) between the wall rock and gouge layer in the marginal portion of cylindrical specimens. Calcite grains of the wall rock adjacent to the slip zone deform by dislocation glide when subjected to frictional heating and a lower strain rate than that of the principal slip zone. The very fine (2-5 μm) calcite grains in the gouge layer show a foam structure with relatively straight grain boundaries and 120° triple junctions. This foam structure is presumed to develop by welding at high temperature and low strain once slip is localized along the central layer. We suggest that a seismic event can be inferred from deformed marbles, given: (i) the presence of welded gouge with foam structure in a fault zone where wall rocks show no evidence of thermal metamorphism and (ii) a thin plastically deformed layer immediately adjacent to the principal slip zone of a cataclastic fault zone.

Finite-Larmor-radius stability theory of EBT plasmas

International Nuclear Information System (INIS)

Berk, H.L.; Cheng, C.Z.; Rosenbluth, M.N.; Van Dam, J.W.

1982-11-01

An eikonal ballooning-mode formalism is developed to describe curvature-driven modes of hot electron plasmas in bumpy tori. The formalism treats frequencies comparable to the ion-cyclotron frequency, as well as arbitrary finite Larmor radius and field polarization, although the detailed analysis is restricted to E/sub parallel/ = 0. Moderate hot-electron finite-Larmor-radius effects are found to lower the background beta core limit, whereas strong finite-Lamor-radius effects produce stabilization

Incidence of plastic debris in Sooty Tern nests: A preliminary study on Trindade Island, a remote area of Brazil.

Science.gov (United States)

de Souza Petersen, Elisa; Krüger, Lucas; Dezevieski, Alexandre; Petry, MariaVirginia; Montone, Rosalinda Carmela

2016-04-15

Plastic is abundant in the oceans, reaching pelagic zones away from continents. Here we present the first recordings of plastic used as nest material in Sooty Tern nests, on a remote oceanic island. We describe our findings in terms of quantity, size and color of plastic debris. A total of 78 plastics were noted in 54 nests. Four color categories were found: Blue, White, Green and Red. Blue fragments were the most frequent color, present three times as much as white debris. This pattern was present despite blue fragments being smaller and lighter. The plastic debris of lowest frequency were the larger and heavier pieces (red). To our knowledge this is the first record of plastic in Sooty Tern nests. Trindade Island is on an oceanic zone expected to accumulate garbage due to the dynamic ocean currents. Such findings call for a closer inspection of pollution in the Atlantic Ocean. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microplastic-associated bacterial assemblages in the intertidal zone of the Yangtze Estuary.

Science.gov (United States)

Jiang, Peilin; Zhao, Shiye; Zhu, Lixin; Li, Daoji

2018-05-15

Plastic trash is common in oceans. Terrestrial and marine ecosystem interactions occur in the intertidal zone where accumulation of plastic frequently occurs. However, knowledge of the plastic-associated microbial community (the plastisphere) in the intertidal zone is scanty. We used high-throughput sequencing to profile the bacterial communities attached to microplastic samples from intertidal locations around the Yangtze estuary in China. The structure and composition of plastisphere communities varied significantly among the locations. We found the taxonomic composition on microplastic samples was related to their sedimentary and aquatic origins. Correlation network analysis was used to identify keystone bacterial genera (e.g. Rhodobacterales, Sphingomonadales and Rhizobiales), which represented important microbial associations within the plastisphere community. Other species (i.e. potential pathogens) were considered as hitchhikers in the plastic attached microbial communities. Metabolic pathway analysis suggested adaptations of these bacterial assemblages to the plastic surface-colonization lifestyle. These adaptations included reduced "cell motility" and greater "xenobiotics biodegradation and metabolism." The findings illustrate the diverse microbial assemblages that occur on microplastic and increase our understanding of plastisphere ecology. Copyright © 2017 Elsevier B.V. All rights reserved.

Correlation between quarter-point angle and nuclear radius

Science.gov (United States)

Ma, Wei-Hu; Wang, Jian-Song; Mukherjee, S.; Wang, Qi; Patel, D.; Yang, Yan-Yun; Ma, Jun-Bing; Ma, Peng; Jin, Shi-Lun; Bai, Zhen; Liu, Xing-Quan

2017-04-01

The correlation between quarter-point angle of elastic scattering and nuclear matter radius is studied systematically. Various phenomenological formulae with parameters for nuclear radius are adopted and compared by fitting the experimental data of quarter point angle extracted from nuclear elastic scattering reaction systems. A parameterized formula related to binding energy is recommended, which gives a good reproduction of nuclear matter radii of halo nuclei. It indicates that the quarter-point angle of elastic scattering is quite sensitive to the nuclear matter radius and can be used to extract the nuclear matter radius. Supported by National Natural Science Foundation of China (U1432247, 11575256), National Basic Research Program of China (973 Program)(2014CB845405 and 2013CB83440x) and (SM) Chinese Academy of Sciences President’s International Fellowship Initiative (2015-FX-04)

Protected areas in the Atlantic facing the hazards of micro-plastic pollution: first diagnosis of three islands in the Canary Current.

Science.gov (United States)

Baztan, Juan; Carrasco, Ana; Chouinard, Omer; Cleaud, Muriel; Gabaldon, Jesús E; Huck, Thierry; Jaffrès, Lionel; Jorgensen, Bethany; Miguelez, Aquilino; Paillard, Christine; Vanderlinden, Jean-Paul

2014-03-15

Coastal zones and the biosphere as a whole show signs of cumulative degradation due to the use and disposal of plastics. To better understand the manifestation of plastic pollution in the Atlantic Ocean, we partnered with local communities to determine the concentrations of micro-plastics in 125 beaches on three islands in the Canary Current: Lanzarote, La Graciosa, and Fuerteventura. We found that, in spite of being located in highly-protected natural areas, all beaches in our study area are exceedingly vulnerable to micro-plastic pollution, with pollution levels reaching concentrations greater than 100 g of plastic in 1l of sediment. This paper contributes to ongoing efforts to develop solutions to plastic pollution by addressing the questions: (i) Where does this pollution come from?; (ii) How much plastic pollution is in the world's oceans and coastal zones?; (iii) What are the consequences for the biosphere?; and (iv) What are possible solutions? Copyright © 2014 Elsevier Ltd. All rights reserved.

Earthquake prediction research with plastic nuclear track detectors

International Nuclear Information System (INIS)

Woith, H.; Enge, W.; Beaujean, R.; Oschlies, K.

1988-01-01

Since 1984 a German-Turkish project on earthquake prediction research has been operating at the North Anatolian fault zone in Turkey. Among many other parameters changes in Radon emission have also been investigated. Plastic nuclear track detectors (Kodak cellulose nitrate LR 115) are used to record alpha-particles emitted from Radon and Thoron atoms and their daughter isotopes. The detectors are replaced and analyzed every 3 weeks. Thus a quasi-continuous time sequence of the Radon soil gas emission is recorded. We present a comparison between measurements made with electronic counters and plastic track detectors. (author)

Equation of limiting plasticity of the metal upon complex stress state

International Nuclear Information System (INIS)

Tin'gaev, A.K.

2002-01-01

A method for evaluation of the limiting plasticity of the metal in the zones of complex 3D stress state is presented. An analytic equation is derived for limiting plasticity. Parameters of the equation are expresses through the standard characteristics of the mechanical properties determined upon static tension of the smooth sample. Introduced into the obtained analytical equation is a universal fracture constant which indirectly characterizes the state of the material from the point of view of its capacity for elastic overstrain relaxation in the form of plastic flow or fracture. The new equation makes it possible to estimate the limiting plasticity of the metal in a state of complex stress on the basis of traditional characteristics of mechanical properties, which are not difficult to determine [ru

An application of the recrystallization method for the observation of plastic strain distribution around SCC cracks in sensitized SUS 304 stainless steels

International Nuclear Information System (INIS)

Tokiwai, Moriyasu

1981-01-01

Various types of stress corrosion cracking (SCC) testing methods have been developed since the SCC was discovered in type 304 stainless steel of BWR cooling pipes. With regard to the countermeasures for SCC, it is essential to evaluate the SCC susceptibility under the simulated or accelerated testing conditions. Among various acceleration SCC tests, the slow strain rate technique (SSRT) test has been used most widely. The SCC susceptibility, in almost cases, has been evaluated not on the base of the crack behavior but of the reduction of stress or strain under the corrosive environment. It is well known that the intensively deformed zone (plastic zone) is formed at the crack tip in fatigue and creep phenomena, but such plastic zone related with the resistance of crack extention has not been studied in SCC phenomenon. The objective of this study is to confirm the existence of the plastic zone at tips of SCC cracks by the application of the recrystallization method. The shape and the distribution of the plastic zone was measured by use of optical and scanning electron microscope in sensitized specimens SSRT tested in high temperature water containing various concentrations of dissolved oxygen. Results obtained are discussed in relation to the susceptibility of SCC. (author)

Numerical Radius Inequalities for Finite Sums of Operators

Directory of Open Access Journals (Sweden)

Mirmostafaee Alireza Kamel

2014-12-01

Full Text Available In this paper, we obtain some sharp inequalities for numerical radius of finite sums of operators. Moreover, we give some applications of our result in estimation of spectral radius. We also compare our results with some known results.

The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

KAUST Repository

Có zar, André s; Martí , Elisa; Duarte, Carlos M.; Garcí a-de-Lomas, Juan; van Sebille, Erik; Ballatore, Thomas J.; Eguí luz, V. M.; Gonzá lez-Gordillo, J. Ignacio; Pedrotti, Maria L.; Echevarrí a, Fidel; Troublè , Romain; Irigoien, Xabier

2017-01-01

The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources

On cavitation instabilities with interacting voids

DEFF Research Database (Denmark)

Tvergaard, Viggo

2012-01-01

voids so far apart that the radius of the plastic zone around each void is less than 1% of the current spacing between the voids, can still affect each others at the occurrence of a cavitation instability such that one void stops growing while the other grows in an unstable manner. On the other hand...

Incorporation of ladle furnace slag in ceramic formulations: study of extrusion zones

International Nuclear Information System (INIS)

Feitosa, E.F.; Santana, C.M.; Luna, D.S.; Santos, D.M.S.; Silva, G.S.; Noleto, L.T.; Almeida, N.C.; Rabelo, A.A.; Fagury Neto, E.

2016-01-01

This study aimed to investigate the effect of incorporation of ladle furnace slag (LFS) in two clays with higher and lower plasticity, used for the manufacture of structural ceramics. The LFS from a local steel making plant was added to ceramic compositions in proportions of 8 %, 14 % and 16 %. The formulations were tested in appropriate equipment that measures the liquid limit and plastic limit. The property examined was the plasticity index, in order to make a study of the extrusion zones. Results showed that the addition of slag into clay mixtures alters the plasticity; however, the extrusion process was not hampered. (author)

Crystal plasticity modeling of irradiation growth in Zircaloy-2

Science.gov (United States)

Patra, Anirban; Tomé, Carlos N.; Golubov, Stanislav I.

2017-08-01

A physically based reaction-diffusion model is implemented in the visco-plastic self-consistent (VPSC) crystal plasticity framework to simulate irradiation growth in hcp Zr and its alloys. The reaction-diffusion model accounts for the defects produced by the cascade of displaced atoms, their diffusion to lattice sinks and the contribution to crystallographic strain at the level of single crystals. The VPSC framework accounts for intergranular interactions and irradiation creep, and calculates the strain in the polycrystalline ensemble. A novel scheme is proposed to model the simultaneous evolution of both, number density and radius, of irradiation-induced dislocation loops directly from experimental data of dislocation density evolution during irradiation. This framework is used to predict the irradiation growth behaviour of cold-worked Zircaloy-2 and trends compared to available experimental data. The role of internal stresses in inducing irradiation creep is discussed. Effects of grain size, texture and external stress on the coupled irradiation growth and creep behaviour are also studied and compared with available experimental data.

Transient drawdown solution for a constant pumping test in finite two-zone confined aquifers

Directory of Open Access Journals (Sweden)

C.-T. Wang

2012-02-01

Full Text Available The drawdown solution has been widely used to analyze pumping test data for the determination of aquifer parameters when coupled with an optimization scheme. The solution can also be used to predict the drawdown due to pumping and design the dewatering system. The drawdown solution for flow toward a finite-radius well with a skin zone in a confined aquifer of infinite extent in radial direction had been developed before. To our best knowledge, the drawdown solution in confined aquifers of finite extent with a skin zone so far has never before been presented in the groundwater literature. This article presents a mathematical model for describing the drawdown distribution due to a constant-flux pumping from a finite-radius well with a skin zone in confined aquifers of finite extent. The analytical solution of the model is developed by applying the methods of Laplace transforms, Bromwich contour integral, and residue theorem. This solution can be used to investigate the effects of finite boundary and conductivity ratio on the drawdown distribution. In addition, the inverse relationship between Laplace- and time-domain variables is used to develop the large time solution which can reduce to the Thiem solution if there is no skin zone.

Power decoding Reed-Solomon codes up to the Johnson radius

DEFF Research Database (Denmark)

Rosenkilde, Johan Sebastian Heesemann

2018-01-01

Power decoding, or "decoding using virtual interleaving" is a technique for decoding Reed-Solomon codes up to the Sudan radius. Since the method's inception, it has been an open question if it is possible to use this approach to decode up to the Johnson radius - the decoding radius of the Guruswami...

77 FR 64718 - Safety Zone; Steam Ship Col. James M. Schoonmaker Relocation Project, Maumee River, Toledo, OH

Science.gov (United States)

2012-10-23

...The Coast Guard is establishing a temporary Safety Zone on the waters of Maumee River, Toledo, Ohio, in support of the relocation of S/S Col. James M. Schoonmaker (hereinafter referred to as `the Schoonmaker'). This temporary safety zone will encompass all waters of the Maumee River within a 100 yard radius of the Schoonmaker as it makes its transit from International Park to Skyway Marina. This temporary Safety Zone is necessary to protect persons operating around the area.

Experimental study of plastic responses of pipe elbows

International Nuclear Information System (INIS)

Greenstreet, W.L.

1978-01-01

Load-deflection responses were determined experimentally for sixteen 152.4-mm (6-in.) (nominal) commercial carbon steel pipe elbows and four 152.4-mm (6-in.) stainless steel elbows. Each specimen was loaded with an external force of sufficient magnitude to produce predominantly plastic response. The influences of bend radius and wall thickness were studied, as well as the effect of internal prssure on load-deflection behavior. Comparisons of results from stainless steel and from carbon steel elbows indicate differences in responses attributable to material differences. The results were interpreted in terms of limit analysis concepts, and collapse loads were determined. Trends given by the collapse loads are identified and discussed

Strain gradient plasticity modeling of hydrogen diffusion to the crack tip

DEFF Research Database (Denmark)

Martínez Pañeda, Emilio; del Busto, S.; Niordson, Christian Frithiof

2016-01-01

to characterize the gradient-enhanced stress elevation and subsequent diffusion of hydrogen towards the crack tip. Results reveal that GNDs, absent in conventional plasticity predictions, play a fundamental role on hydrogen transport ahead of a crack. SGP estimations provide a good agreement with experimental......In this work hydrogen diffusion towards the fracture process zone is examined accounting for local hardening due to geometrically necessary dislocations (GNDs) by means of strain gradient plasticity (SGP). Finite element computations are performed within the finite deformation theory...

Plastic scintillation dosimetry: Optimal selection of scintillating fibers and scintillators

International Nuclear Information System (INIS)

Archambault, Louis; Arsenault, Jean; Gingras, Luc; Sam Beddar, A.; Roy, Rene; Beaulieu, Luc

2005-01-01

Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter

Plasticity around an Axial Surface Crack in a Cylindrical Shell

DEFF Research Database (Denmark)

Krenk, Steen

1979-01-01

of the yield zone. The model is used to analyse published test data on surface cracked pressurised pipes. The analysis consists in COD evaluation and estimate of failure as a consequence of plastic instability. A method is proposed which deals with the problem by simultaneous analysis of a number of cracks......This paper presents a plasticity model for deep axial surface cracks in pressurised pipes. The model is used in an investigation of the relative merits of fracture criteria based on COD and plastic instability. Recent investigations have shown that the inconsistency of the singular bending stress...... on the bending stresses is considerable. In the case of surface cracks moments are induced due to the eccentricity of the crack and transverse shear effects should therefore be included. A plasticity model for a rectangular axial surface crack is developed. Like a previous surface crack model by Erdogen...

Demarcating Circulation Regimes of Synchronously Rotating Terrestrial Planets within the Habitable Zone

Science.gov (United States)

Haqq-Misra, Jacob; Wolf, Eric. T.; Joshi, Manoj; Zhang, Xi; Kopparapu, Ravi Kumar

2018-01-01

We investigate the atmospheric dynamics of terrestrial planets in synchronous rotation within the habitable zone of low-mass stars using the Community Atmosphere Model. The surface temperature contrast between the day and night hemispheres decreases with an increase in incident stellar flux, which is opposite the trend seen in gas giants. We define three dynamical regimes in terms of the equatorial Rossby deformation radius and the Rhines length. The slow rotation regime has a mean zonal circulation that spans from the day to the night sides, which occurs for planets around stars with effective temperatures of 3300–4500 K (rotation period > 20 days), with both the Rossby deformation radius and the Rhines length exceeding the planetary radius. Rapid rotators have a mean zonal circulation that partially spans a hemisphere and with banded cloud formation beneath the substellar point, which occurs for planets orbiting stars with effective temperatures of less than 3000 K (rotation period days), with the Rossby deformation radius less than the planetary radius. In between is the Rhines rotation regime, which retains a thermally direct circulation from the day side to the night side but also features midlatitude turbulence-driven zonal jets. Rhines rotators occur for planets around stars in the range of 3000–3300 K (rotation period ∼5–20 days), where the Rhines length is greater than the planetary radius but the Rossby deformation radius is less than the planetary radius. The dynamical state can be observationally inferred from a comparison of the morphologies of the thermal emission phase curves of synchronously rotating planets.

Evolution of plastic deformation and its effect on mechanical properties of laser additive repaired Ti64ELI titanium alloy

Science.gov (United States)

Zhao, Zhuang; Chen, Jing; Tan, Hua; Lin, Xin; Huang, Weidong

2017-07-01

In this paper, laser additive manufacturing (LAM) technology with powder feeding has been employed to fabricate 50%LAMed specimens (i.e. the volume fraction of the laser deposited zone was set to 50%). With aid of the 3D-DIC technique, the tensile deformation behavior of 50%LAMed Ti64ELI titanium alloy was investigated. The 50%LAMed specimen exhibits a significant characteristic of strength mismatch due to the heterogeneous microstructure. The tensile fracture of 50%LAMed specimen occurs in WSZ (wrought substrate zone), but the tensile strength is slightly higher and the plastic elongation is significantly lower than that of the wrought specimen. The 3D-DIC results shows that the 50%LAMed specimen exhibits a characteristic of dramatic plastic strain heterogeneity and the maximal strain is invariably concentrated in WSZ. The ABAQUS simulation indicates that, the LDZ (laser deposited zone) can constrain the plastic deformation of the WSZ and biaxial stresses develop at the interface after yielding.

78 FR 39707 - Foreign-Trade Zone (FTZ) 277-Western Maricopa County, Arizona; Notification of Proposed...

Science.gov (United States)

2013-07-02

....; (Plastic Containers) Goodyear, Arizona The Greater Maricopa Foreign Trade Zone, Inc. (GMFTZ), grantee of... application is currently pending to expand FTZ 277 and include the Schoeller Arca facility as a usage-driven... plastic containers for industrial/commercial materials handling applications. Pursuant to 15 CFR 400.14(b...

Spectroscopy of muonic atoms and the proton radius puzzle

Science.gov (United States)

Antognini, Aldo

2017-09-01

We have measured several 2 S -2 P transitions in muonic hydrogen (μp), muonic deuterium (μd) and muonic helium ions (μ3He, μ4He). From muonic hydrogen we extracted a proton charge radius 20 times more precise than obtained from electron-proton scattering and hydrogen high-precision laser spectroscopy but at a variance of 7 σ from these values. This discrepancy is nowadays referred to as the proton radius puzzle. New insight has been recently provided by the first determination of the deuteron charge radius from laser spectroscopy of μd. The status of the proton charge radius puzzle including the new insights obtained by μd spectroscopy will be discussed. Work supported by the Swiss National Science Foundation SNF-200021-165854 and the ERC CoG. #725039.

The relationship between Anopheles gambiae density and rice cultivation in the savannah zone and forest zone of Côte d'Ivoire.

Science.gov (United States)

Briët, Olivier J T; Dossou-Yovo, Joel; Akodo, Elena; van de Giesen, Nick; Teuscher, Thomas M

2003-05-01

In 13 villages in the savannah zone and 21 villages in the forest zone of Côte d'Ivoire, the biting density of the principal malaria vector, Anopheles gambiae, was studied as a function of rice cultivation in the inland valleys in a 2-km radius around each village. In the savannah villages, during the main season cropping period, surface water on rice-cultivated and to a lesser extent on uncultivated inland valleys seems to contribute strongly to the A. gambiae population density. For the off-season cropping period (which starts after the first light rains in the savannah zone), correlations were weaker. Breeding sites other than in inland valleys may play an important role in the savannah zone. In the forest zone, however, the A. gambiae population density was strongly correlated with the surface water availability (SWA) in the rice-cultivated inland valleys, whereas the correlation with the SWA in other (uncultivated) inland valleys was weak. The requirement of sunlit breeding sites for A. gambiae might explain this difference between zones. In the forest zone, only inland valleys cleared for rice cultivation meet this requirement, whereas all other inland valleys are covered with dense vegetation. In the savannah zone, however, most undergrowth is burnt during the dry season, which permits sunlight to reach puddles resulting from the first rains.

Plastic

International Nuclear Information System (INIS)

Jeong Gi Hyeon

1987-04-01

This book deals with plastic, which includes introduction for plastic, chemistry of high polymers, polymerization, speciality and structure of a high molecule property of plastic, molding, thermosetting plastic, such as polyethylene, polyether, polyamide and polyvinyl acetyl, thermal plastic like phenolic resins, xylene resins, melamine resin, epoxy resin, alkyd resin and poly urethan resin, new plastic like ionomer and PPS resin, synthetic laminated tape and synthetic wood, mixed materials in plastic, reprocessing of waste plastic, polymer blend, test method for plastic materials and auxiliary materials of plastic.

Finite Larmor radius stabilization of ballooning modes in tokamaks

International Nuclear Information System (INIS)

Tsang, K.T.

1980-07-01

A ballooning mode equation that includes full finite Larmor radius effects has been derived from the Vlasov equation for a circular tokamak equilibrium. Numerical solution of this equation shows that finite Larmor radius effects are stabilizing

Material Weakening of Slip Zone Soils Induced by Water Level Fluctuation in the Ancient Landslides of Three Gorges Reservoir

Directory of Open Access Journals (Sweden)

Yu-Yong Jiao

2014-01-01

Full Text Available This experimental study investigated the effect of repeated wetting and drying on the reduction of slip zone soils taken from the Huangtupo landslide in the Three Gorges Reservoir, China. The variation process of the physical property and substance composition of the slip zone soils under the wetting-drying cycles was studied through liquid and plastic limit test and X-ray diffraction test. The results indicate that (1 the shearing strength of the slip zone soil dramatically decreased after one wetting-drying cycle and then gradually decreased until reaching a relatively stable state at the fourth cycle; (2 the plasticity index of the slip zone soil varied with increasing number of cycles and a variation process opposite to that of the strength value was observed; and (3 the clay mineral content in the slip zone soil increased and the calcite and quartz contents relatively decreased with increasing number of cycles. The variations in the plasticity index of the slip zone soil, as well as the increase in its clay mineral content, play important roles in the strength reduction. The results of this study provide a foundation for revealing the deformation and damage mechanism of landslides in reservoir banks.

MUSE: Measuring the proton radius with muon-proton scattering

Energy Technology Data Exchange (ETDEWEB)

Bernauer, Jan Christopher [Massachusetts Institute of Technology, Cambridge (United States)

2014-07-01

The proton radius has been measured so far using electron-proton scattering, electronic Hydrogen spectroscopy and muonic Hydrogen spectroscopy, the latter producing a much more accurate, but seven sigma different, result, leading to the now famous proton radius puzzle. The MUSE collaboration aims to complete the set of measurements by using muon scattering to determine the proton radius and to shed light on possible explanations of the discrepancy. The talk gives an overview of the experiment motivation and design and a status report on the progress.

Fruit sphere microenvironments and berry phenolic content of Cabernet Sauvignon (Vitis vinifera L. cultivated under rain-shelter systems with coloured plastic film

Directory of Open Access Journals (Sweden)

Jiang-Fei MENG

Full Text Available Abstract Rain-shelter cultivation has been proven an important cultivation method for grape-plantings in continental monsoon climate zones, of which white plastic films are the most common shelter material. However, while this method and material reduces the occurrence of the disease, it can also decrease the grape berry quality. Five colours (including red, yellow, blue, purple, and white of plastic films were covered above Cabernet Sauvignon (Vitis vinifera L. grapevine rows before veraison. Rain-shelter cultivation reduced air temperature, wind speed, and total solar radiation and enhanced relative humidity in the fruit sphere of grapevines. For each particular colour plastic film, the irradiance of its corresponding spectrum band in the canopy of vines was higher than with other colour plastic films. Meanwhile, the blue plastic film treatment significantly promoted the accumulation of total phenolics, anthocyanins, flavonoids, tannins, and phenolic acids more than the other colours of plastic films. Blue plastic films are more beneficial for berry quality promotion of wine grapes, especially Cabernet Sauvignon, under rain-shelter cultivation in continental monsoon climate zones.

Upper pinch radius limit in EXTRAP

International Nuclear Information System (INIS)

Lehnert, B.

1989-12-01

A simple static equilibrium model of the Z-pinch is considered where a hot plasma core is surrounded by a cold-mantle (gas blanket). The pinch radius, defined as the radial extension of the fully ionized plasma core, is uniquely determined by the plasma particle. momentum and heat balance equations. In Extrap configurations an octupole field is introduced which imposes a magnetic separatrix on Z-pinch geometry. This makes the conditions for Extrap equilibrium 'overdetermined' when the characteristic pinch radium given by the plasma parameters tends to exceed the characteristic radius of the magnetic separatrix. In this case no conventional pinch equilibrium can exist, and part of the current which is forced into the plasma discharge by external sources must be channelled outside of the separatrix, i.e. into the surrounding support structure of the Extrap conductors and the vessel walls. A possibly existing bootstrap current in the plasma boundary layer is further expected to be 'scraped off' in this case. The present paper gives some illustrations of the marginal case of this upper pinch radius limit, in a state where the pinch current is antiparallel to the external rod currents which generate the octupole field. (authors)

Modelling global distribution, risk and mitigation strategies of floating plastic pollution

Science.gov (United States)

van Sebille, Erik; Wilcox, Chris; Sherman, Peter; Hardesty, Britta Denise; Lavender Law, Kara

2016-04-01

Microplastic debris floating at the ocean surface can harm marine life. Understanding the severity of this harm requires knowledge of plastic abundance and distributions. Dozens of expeditions measuring microplastics have been carried out since the 1970s, but they have primarily focused on the North Pacific and North Atlantic accumulation zones, with much sparser coverage elsewhere. Here, we use the largest dataset of microplastic measurements assembled to date to assess the confidence we can have in global estimates of microplastic abundance and mass. We use a rigorous statistical framework to standardise a global dataset of plastic marine debris measured using surface-trawling plankton nets and couple this with three different ocean circulation models to spatially interpolate the observations. Our estimates show that the accumulated number of microplastic particles in 2014 ranges from 15 to 51 trillion particles, weighing between 93 and 236 thousand metric tons. A large fraction of the uncertainty in these estimates comes from sparse sampling in coastal and Southern Hemisphere regions. We then use this global distribution of small floating plastic debris to map out where in the ocean the risk to marine life (in particular seabirds and plankton growth) is greatest, using a quantitative risk framework. We show that the largest risk occurs not necessarily in regions of high plastic concentration, but rather in regions of extensive foraging with medium-high plastic concentrations such as coastal upwelling regions and the Southern Ocean. Finally, we use the estimates of distribution to investigate where in the ocean plastic can most optimally be removed, assuming hypothetical clean-up booms following the ideas from The Ocean Cleanup project. We show that mitigation of the plastic problem can most aptly be done near coastlines, particularly in Asia, rather than in the centres of the gyres. Based on these results, we propose more focus on the coastal zones when

GREEN PLASTIC: A NEW PLASTIC FOR PACKAGING

OpenAIRE

Mr. Pankaj Kumar*, Sonia

2016-01-01

This paper gives a brief idea about a new type of plastic called as bio-plastic or green plastic. Plastic is used as a packaging material for various products, but this plastic is made up of non renewable raw materials. There are various disadvantages of using conventional plastic like littering, CO2 production, non-degradable in nature etc. To overcome these problems a new type of plastic is discovered called bio-plastic or green plastic. Bio-plastic is made from renewable resources and also...

Study Application of RADIUS Protocol on Ethernet

Institute of Scientific and Technical Information of China (English)

GUO Fang; YANG Huan-yu; LI Hong

2004-01-01

This paper presents how to apply the RADIUS (Remote Authentication Dial In User Service)protocol ,which is generally applied to dial-up network, to the authentication & charge of Broad Band accessing control system on Ethernet. It is provided that the Broad Band accessing control system included a self-designed communication protocol is used in communicating between an terminal user and Network Access Server .The interface module on the servers side and the Radius system is also given in this article.

A brief history of plastic surgery in Iran.

Science.gov (United States)

Kalantar-Hormozi, Abdoljalil

2013-03-01

 Although the exact time of performing plastic surgery is not addressed in the medical and historical literature, it can be supposed that these surgical procedures have a long and fascinating history.  Recent excavations provided many documents regarding the application of medical instruments, surgical and even reconstructive procedures during the pre-historic and ancient periods. Actually, there is no historical definite time-zone separating general and cosmetic operations in the pre-modern time; however, historically there have been many surgeons who tried to perform reconstructive procedures during their usual medical practice. This article presents a brief look at the history of plastic surgery form the ancient to the contemporary era, with a special focus on Iran.

The impact law of confining pressure and plastic parameter on Dilatancy of rock

Science.gov (United States)

Wang, Bin; Zhang, Zhenjie; Zhu, Jiebing

2017-08-01

Based on cyclic loading-unloading triaxle test of marble, the double parameter dilation angle model is established considering confining pressure effect and plastic parameter. Research shows that not only the strength but also the militancy behavior is highly depended on its confining pressure and plastic parameter during process of failure. Dilation angle evolution law shows obvious nonlinear characteristic almost with a rapid increase to the peak and then decrease gradually with plastic increasing, and the peak dilation angle value is inversely proportional with confining pressure. The proposed double parameter nonlinear dilation angle model can be used to well describe the Dilatancy of rock, which helps to understand the failure mechanism of surrounding rock mass and predict the range of plastic zone.

Generalized spectral radius and its max algebra version

Czech Academy of Sciences Publication Activity Database

Müller, Vladimír; Peperko, A.

2013-01-01

Roč. 439, č. 4 (2013), s. 1006-1016 ISSN 0024-3795 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional support: RVO:67985840 Keywords : generalized spectral radius * joint spectral radius * Berger-Wang formula Subject RIV: BA - General Mathematics Impact factor: 0.983, year: 2013 http://www.sciencedirect.com/science/article/pii/S0024379512007380

On higher-order boundary conditions at elastic-plastic boundaries in strain-gradient plasticity

DEFF Research Database (Denmark)

Niordson, Christian Frithiof

2008-01-01

are suppressed by using a very high artificial hardening modulus. Through numerical studies of pure bending under plane strain conditions, it is shown that this method predicts the build-up of higher order stresses in the pseudo-elastic regime. This has the effect of delaying the onset of incipient yield......, as well as extending the plastic zone further toward the neutral axis of the beam, when compared to conventional models. Arguments supporting the present method are presented that rest on both mathematical and physical grounds. The results obtained are compared with other methods for dealing with higher...

On tidal radius determination for a globular cluster

International Nuclear Information System (INIS)

Ninkovic, S.

1985-01-01

A tidal radius determination for a globular cluster based on its density minimum, which is caused by the galactic tidal forces and derivable from a model of the Galaxy, is proposed. Results obtained on the basis of the Schmidt model for two clusters are in a satisfactory agreement with those obtained earlier by means of other methods. A mass determination for the clusters through the tidal radius, when the latter one is identified with the cluster perigalactic distance, yields unusually large mass values. Probably, the tidal radius should be identified with the instantaneous galactocentric distance. Use of models more recent than the Schmidt one indicates that a globular cluster may contain a significant portion of an invisible interstellar matter. (author)

The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

NARCIS (Netherlands)

Cózar, Andrés; Martí, Elisa; Duarte, Carlos M; García-de-Lomas, Juan; van Sebille, Erik|info:eu-repo/dai/nl/304831921; Ballatore, Thomas J; Eguíluz, Victor M; González-Gordillo, J Ignacio; Pedrotti, Maria L; Echevarría, Fidel; Troublè, Romain; Irigoien, Xabier

The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively

Plastic Deformation of Pressured Metallic Glass

Directory of Open Access Journals (Sweden)

Yun Cheng

2017-11-01

Full Text Available Although pressured metallic glass (MG has been reported in the literature; there are few studies focusing on pressure effects on the structure; dynamics and its plastic deformation. In this paper; we report on and characterize; via molecular dynamics simulation, the structure and dynamics heterogeneity of pressured MGs, and explore a causal link between local structures and plastic deformation mechanism of pressured glass. The results exhibit that the dynamical heterogeneity of metallic liquid is more pronounced at high pressure, while the MGs were less fragile after the release of external pressure, reflected by the non-Gaussian parameter (NGP. High pressure glass shows better plastic deformation; and the local strain zone distributed more uniformly than of in normal glass. Further research indicates that although the number of icosahedrons in pressured glass was much larger than that in normal glass, while the interpenetrating connections of icosahedra (ICOI exhibited spatial correlations were rather poor; In addition, the number of ‘fast’ atoms indexed by the atoms’ moving distance is larger than that in normal glass; leading to the sharp decreasing in number of icosahedrons during deformation. An uniform distribution of ‘fast’ atoms also contributed to better plastic deformation ability in the pressured glass. These findings may suggest a link between the deformation and destruction of icosahedra with short-range order.

Coulomb corrections to scattering length and effective radius

International Nuclear Information System (INIS)

Mur, V.D.; Kudryavtsev, A.E.; Popov, V.S.

1983-01-01

The problem considered is extraction of the ''purely nuclear'' scattering length asub(s) (corresponding to the strong potential Vsub(s) at the Coulomb interaction switched off) from the Coulomb-nuclear scattering length asub(cs), which is an object of experimental measurement. The difference between asub(s) and asub(cs) is especially large if the potential Vsub(s) has a level (real or virtual) with an energy close to zero. For this case formulae are obtained relating the scattering lengths asub(s) and asub(cs), as well as the effective radii rsub(s) and rsub(cs). The results are extended to states with arbitrary angular momenta l. It is shown that the Coulomb correction is especially large for the coefficient with ksup(2l) in the expansion of the effective radius; in this case the correction contains a large logarithm ln(asub(B)/rsub(0)). The Coulomb renormalization of other terms in the effective radius espansion is of order (rsub(0)/asub(B)), where r 0 is the nuclear force radius, asub(B) is the Bohr radius. The obtained formulae are tried on a number of model potentials Vsub(s), used in nuclear physics

Elastic-plastic deformation of fiber composites with a tetragonal structure

Energy Technology Data Exchange (ETDEWEB)

Makarova, E.IU.; Svistkova, L.A. (Permskii Politekhnicheskii Institut, Perm (USSR))

1991-02-01

Results of numerical solutions are presented for elastic-plastic problems concerning arbitrary loading of unidirectional composites in the transverse plane. The nucleation and evolution of microplastic zones in the matrix and the effect of this process on the macroscopic characteristics of the composite are discussed. Attention is also given to the effect of the fiber shape on the elastic-plastic deformation of the matrix and to deformation paths realized in simple microdeformation processes. The discussion is illustrated by results obtained for a composite consisting of a VT1-0 titanium alloy matrix reinforced by Ti-Mo fibers.

Size effects in olivine control strength in low-temperature plasticity regime

Science.gov (United States)

Kumamoto, K. M.; Thom, C.; Wallis, D.; Hansen, L. N.; Armstrong, D. E. J.; Goldsby, D. L.; Warren, J. M.; Wilkinson, A. J.

2017-12-01

The strength of the lithospheric mantle during deformation by low-temperature plasticity controls a range of geological phenomena, including lithospheric-scale strain localization, the evolution of friction on deep seismogenic faults, and the flexure of tectonic plates. However, constraints on the strength of olivine in this deformation regime are difficult to obtain from conventional rock-deformation experiments, and previous results vary considerably. We demonstrate via nanoindentation that the strength of olivine in the low-temperature plasticity regime is dependent on the length-scale of the test, with experiments on smaller volumes of material exhibiting larger yield stresses. This "size effect" has previously been explained in engineering materials as a result of the role of strain gradients and associated geometrically necessary dislocations in modifying plastic behavior. The Hall-Petch effect, in which a material with a small grain size exhibits a higher strength than one with a large grain size, is thought to arise from the same mechanism. The presence of a size effect resolves discrepancies among previous experimental measurements of olivine, which were either conducted using indentation methods or were conducted on polycrystalline samples with small grain sizes. An analysis of different low-temperature plasticity flow laws extrapolated to room temperature reveals a power-law relationship between length-scale (grain size for polycrystalline deformation and contact radius for indentation tests) and yield strength. This suggests that data from samples with large inherent length scales best represent the plastic strength of the coarse-grained lithospheric mantle. Additionally, the plastic deformation of nanometer- to micrometer-sized asperities on fault surfaces may control the evolution of fault roughness due to their size-dependent strength.

The creep bending of short radius pipe bends

International Nuclear Information System (INIS)

Spence, John

1975-01-01

In existing and proposed liquid metal fast breeder reactor design the pipework has considerable importance. Parts of the LMFBR include thin walled short radius bends which are expected to operate in the creep regime. In linear elasticity it is known that the assumption of long radius bends is not too severe as far as the flexibility characteristics are concerned although some modifications are necessary for accurate determination of the stresses. No data exists for nonlinear creep. Current work is aimed at elucidating the effect of the various assumptions common to linear elastic theory in so far as they affect the creep characteristics of bends on systems. Herein an energy based analysis using a simple n power constitutive law for stationary creep is employed to derive basic design data for flexibilities and stresses which will be necessary before complete systems can be assessed for creep. The analysis shows on comparison with the long radius work that the assumption of R>r is not much more restrictive in creep than for linear elasticity. Flexibilities for short radius bends appear to be well approximated by the long radius values. Thus the attractive reference stress information already derived may be used directly to find deformations without a complete knowledge of the constitutive relationship. However, stresses are somewhat different. Fortunately the maximum deviation occurs at relatively low levels of stress, the peak stresses being in fair agreement. When n=1 the present results reduce essentially to those obtained from existing linear elastic theory

Particle capture by turbulent recirculation zones measured using long-time Lagrangian particle tracking

Energy Technology Data Exchange (ETDEWEB)

Siu, Y.W. [Hong Kong Securities Institute, Department of Professional Education and Training, Central (China); Taylor, A.M.K.P. [Imperial College London, Department of Mechanical Engineering, London (United Kingdom)

2011-07-15

We have measured the trajectories of particles into, and around, the recirculation zone formed in water flowing through a sudden pipe expansion with radius ratio 1:3.7, at Reynolds numbers between 5,960 and 41,700 over a range of particle Stokes number (here defined as St=(T{sub f})/({tau} p), where T{sub f} is an appropriate mean or turbulent timescale of the fluid flow and a particle relaxation time, {tau}{sub p},) between 6.2 and 51 and drift parameter between 0.3 and 2.8. The particles were thus weakly inertial but nevertheless heavy with a diameter about an order of magnitude larger than the Kolmogorov scale. Trajectories of particles, released individually into the flow, were taken in a Lagrangian framework by a three-dimensional particle tracking velocimeter using a single 25 Hz framing rate intensified CCD camera. Trajectories are quantified by the axial distribution of the locations of particle axial velocity component reversal and the probability distributions of trajectory angle and curvature. The effect of increasing the drift parameter was to reduce the tendency for particles to enter the recirculation zone. For centreline release, the proportion of particles entering the recirculation zone and acquiring a negative velocity decreased from about 80% to none and from about 66% to none, respectively, as the drift parameter increased from 0.3 to 2.8. Almost half of the particles experienced a relatively large change of direction corresponding to a radius of curvature of their trajectory comparable to, or smaller than, the radius of the downstream pipe. This was due to the interaction between these particles and eddies of this size in the downstream pipe and provides experimental evidence that particles are swept by large eddies into the recirculation zone over 1.0 < Z{sup *} < 2.5, where Z{sup *} is axial distance from the expansion plane normalized by the downstream pipe diameter, which was well upstream of the reattachment point at the wall (Z

Fractures of the bilateral distal radius and scaphoid: a case report

Directory of Open Access Journals (Sweden)

Ozkan Korhan

2008-03-01

Full Text Available Abstract Introduction Bilateral fractures of the distal radius and scaphoid are extremely rare injuries. Case presentation A patient with bilateral comminuted, displaced distal fractures of the radius and bilateral fractures of the scaphoid was treated via internal fixation of the scaphoid fractures with Herbert screws and internal fixation of the distal radius fractures with locked volar plating. Conclusion Rigid internal fixation of distal radius and scaphoid fractures is mandatory to start early active rehabilitation of the wrist without the need for wrist immobilization with a plaster or external skeletal fixation.

On dislocation inhomogeneity of electroerosion crater zone in molybdenum single crystals

International Nuclear Information System (INIS)

Larikov, L.N.; Dubovitskaya, N.V.; Zakharov, S.M.

1979-01-01

Methods of diffraction electron microscopy, X-ray analysis and microhardness measurements have been applied to study the inhomogeneity of dislocation structure of the electroerosion crater zone in molybdenum single crystals. Microhardness inhomogeneous distribution in this zone is established, conditioned by changes in dislocation structure as a result of the development of thermally activated processes of the plastic deformation and dynamic recovery. Dislocationless channels are detected in predeformed crystals

Elastic unloading of a disk after plastic deformation by a circular heat source

International Nuclear Information System (INIS)

Gamer, U.; Mack, W.

1987-01-01

Subject of the investigation is the transient stress distribution in an elastic-plastic disk acted upon by a circular heat source. The disk serves as a mechanical model of the rotating anode of an X-ray-tube. The calculation is based on Tresca's yield criterion and the flow rule associatd to it. During heating, a plastic region spreads around the source, which is absorbed by an unloaded zone after the removal of the source. (orig.) [de

Low temperature surface hardening of stainless steel; the role of plastic deformation

DEFF Research Database (Denmark)

Bottoli, Federico; Jespersen, Freja Nygaard; Hattel, Jesper Henri

2016-01-01

: - plastic deformation of metastable austenitic stainless steels leads to the development of strain-induced martensite, which compromises the uniformity and the homogeneity of the expanded austenite zone. - during low temperature surface engineering composition and stress profiles develop. On numerical......Thermochemical surface engineering by nitriding of austenitic stainless steel transforms the surface zone into expanded austenite, which improves the wear resistance of the stainless steel while preserving the stainless behavior. As a consequence of the thermochemical surface engineering, huge...

Numerical Model for Solidification Zones Selection in the Large Ingots

Directory of Open Access Journals (Sweden)

Wołczyński W.

2015-12-01

Full Text Available A vertical cut at the mid-depth of the 15-ton forging steel ingot has been performed by curtesy of the CELSA - Huta Ostrowiec plant. Some metallographic studies were able to reveal not only the chilled undersized grains under the ingot surface but columnar grains and large equiaxed grains as well. Additionally, the structural zone within which the competition between columnar and equiaxed structure formation was confirmed by metallography study, was also revealed. Therefore, it seemed justified to reproduce some of the observed structural zones by means of numerical calculation of the temperature field. The formation of the chilled grains zone is the result of unconstrained rapid solidification and was not subject of simulation. Contrary to the equiaxed structure formation, the columnar structure or columnar branched structure formation occurs under steep thermal gradient. Thus, the performed simulation is able to separate both discussed structural zones and indicate their localization along the ingot radius as well as their appearance in term of solidification time.

Interpreting the stress–strain response of Al micropillars through gradient plasticity

International Nuclear Information System (INIS)

Zhang, Xu; Aifantis, Katerina E.; Ngan, Alfonso H.W.

2014-01-01

Micropillar compression has fascinated the materials and mechanics communities for over a decade, due to the unique stochastic effects and slip zones that dictate their stress–strain curves and microstructure. Although plethora studies exist that capture experimentally the mechanical response of various types of micropillars, limited theoretical models can interpret the observed behavior. Particularly, single crystal micropillars exhibit multiple serrations in their stress–strain response, indicating the activation of slip zones, while bi-crystal pillars, in which the grain boundary lies parallel to the pillar axis, do not display such serrations, but rather a distinct “knee”, which indicates dislocation pileups at the grain boundary. In-situ synchrotron microdiffraction experiments have illustrated that not only dislocations, but also significant plastic strain gradients develop during micropillar compression. In the present study, therefore, appropriate gradient plasticity models that can account for the pillar microstructure, are successfully used to capture the stress–strain response of single- and bi-crystal Al pillars

Pulse-Like Rupture Induced by Three-Dimensional Fault Zone Flower Structures

KAUST Repository

Pelties, Christian; Huang, Yihe; Ampuero, Jean-Paul

2014-01-01

interface. This effect is robust against a wide range of fault zone widths, absence of frictional healing, variation of initial stress conditions, attenuation, and off-fault plasticity. These numerical studies covered two-dimensional problems with fault

DML and Foil Measurements of ETA Beam Radius

International Nuclear Information System (INIS)

Nexsen, W; Weir, J

2005-01-01

Simultaneous measurements of the ETA beam radius have been made with a quartz foil and a diamagnetic loop (DML). While the measurements agreed at some settings they diverged at others. While the DML measures the rms radius of the total beam, the foil measures mainly the core and the divergence can be explained by the presence of a low density halo. Evidence of such a halo from other measurements is presented

Variational principles for the spectral radius of functional operators

International Nuclear Information System (INIS)

Antonevich, A B; Zajkowski, K

2006-01-01

The spectral radius of a functional operator with positive coefficients generated by a set of maps (a dynamical system) is shown to be a logarithmically convex functional of the logarithms of the coefficients. This yields the following variational principle: the logarithm of the spectral radius is the Legendre transform of a convex functional T defined on a set of vector-valued probability measures and depending only on the original dynamical system. A combinatorial construction of the functional T by means of the random walk process corresponding to the dynamical system is presented in the subexponential case. Examples of the explicit calculation of the functional T and the spectral radius are presented.

33 CFR 165.1155 - Security Zone; Diablo Canyon Nuclear Power Plant, Avila Beach, California.

Science.gov (United States)

2010-07-01

... Nuclear Power Plant, Avila Beach, California. 165.1155 Section 165.1155 Navigation and Navigable Waters... Coast Guard District § 165.1155 Security Zone; Diablo Canyon Nuclear Power Plant, Avila Beach... surface to bottom, within a 2,000 yard radius of Diablo Canyon Nuclear Power Plant centered at position 35...

Solar radius change between 1925 and 1979

Science.gov (United States)

Sofia, S.; Dunham, D. W.; Dunham, J. B.; Fiala, A. D.

1983-01-01

From an analysis of numerous reports from different locations on the duration of totality of the solar eclipses on January 24, 1925, and February 26, 1979, it is found that the solar radius at the earlier date was 0.5 arcsec (or 375 km) larger than at the later date. The correction to the standard solar radius found for each eclipse is different when different subsets of the observations are used (for example, edge of path of totality timings compared with central timings). This is seen as suggesting the existence of systematic inaccuracies in our knowledge of the lunar figure. The differences between the corrections for both eclipses, however, are very similar for all subsets considered, indicating that changes of the solar size may be reliably inferred despite the existence of the lunar figure errors so long as there is proper consideration of the distribution of the observations. These results are regarded as strong evidence in support of the occurrence of solar radius changes on shorter than evolutionary time scales.

Solar radius change between 1925 and 1979

International Nuclear Information System (INIS)

Sofia, S.; Fiala, A.D.

1983-01-01

By analysing numerous reports, from different locations, on the duration of totality of the solar eclipses on 24 January 1925, and on 26 February 1979, it was found that the solar radius at the earlier date was 0.5 arc s, or 375 km larger than at the later date. The correction to the standard solar radius found for each eclipse was different when different subsets of the observations were used (for example, edge of path of totality timings compared with central timings), suggesting the existence of systematic inaccuracies in our knowledge of the lunar figure. However, the differences between the corrections for both eclipses were very similar for all subsets considered, indicating that changes of the solar size may be reliably inferred despite the existence of the lunar figure errors, as long as the proper consideration is made of the distribution of the observations. It is considered that these results are strong evidence in support of the occurrence of solar radius changes on shorter than evolutionary time scales. (author)

Electric arc radius and characteristics

International Nuclear Information System (INIS)

Fang, T.M.

1980-01-01

The heat transfer equation of an arc discharge has been solved. The arc is assumed to be a cylinder with negligible axial variation and the dominant heat transfer process is conduction radially inside the column and radiation/convection at the outside edge. The symmetric consideration allows a simple one-dimensional formulation. By taking into account proper variation of the electrical conductivity as function of temperature, the heat balance equation has been solved analytically. The radius of the arc and its current-field characteristics have also been obtained. The conventional results that E approx. I 0 5385 and R approx. I 0 7693 with E being the applied field, I the current, and R the radius of the cylindrical arc, have been proved to be simply limiting cases of our more general characteristics. The results can be applied quite widely including, among others, the neutral beam injection project in nuclear fusion and MHD energy conversion

Approximate solutions for radial travel time and capture zone in unconfined aquifers.

Science.gov (United States)

Zhou, Yangxiao; Haitjema, Henk

2012-01-01

Radial time-of-travel (TOT) capture zones have been evaluated for unconfined aquifers with and without recharge. The solutions of travel time for unconfined aquifers are rather complex and have been replaced with much simpler approximate solutions without significant loss of accuracy in most practical cases. The current "volumetric method" for calculating the radius of a TOT capture zone assumes no recharge and a constant aquifer thickness. It was found that for unconfined aquifers without recharge, the volumetric method leads to a smaller and less protective wellhead protection zone when ignoring drawdowns. However, if the saturated thickness near the well is used in the volumetric method a larger more protective TOT capture zone is obtained. The same is true when the volumetric method is used in the presence of recharge. However, for that case it leads to unreasonableness over the prediction of a TOT capture zone of 5 years or more. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

The earth's radius and the G variation

International Nuclear Information System (INIS)

Canuto, V.M.; City Coll., New York

1981-01-01

It has been assumed that if the gravitational constant G was larger in the past, the Earth's radius had to be smaller. The assertion holds provided the input from microphysics (in particular the equation of state) is independent of G. While this is true for some theories of gravity with variable G it is not so in the scale covariant theory, where the pressure can be affected by a variable G in a way that, for a constant mass of the Earth, a larger G in the past implies a larger Earth's radius. Comparison with recent palaeomagnetic data is presented. (author)

Mass-Radius diagram for compact stars

International Nuclear Information System (INIS)

Carvalho, G A; Jr, R M Marinho; Malheiro, M

2015-01-01

The compact stars represent the final stage in the evolution of ordinary stars, they are formed when a star ceases its nuclear fuel, in this point the process that sustain its stability will stop. After this, the internal pressure can no longer stand the gravitational force and the star colapses [2]. In this work we investigate the structure of these stars which are described by the equations of Tolman-Openheimer-Volkof (TOV) [1]. These equations show us how the pressure varies with the mass and radius of the star. We consider the TOV equations for both relativistic and non-relativistic cases. In the case of compact stars (white dwarfs and neutron stars) the internal pressure that balances the gravitational pressure is essentialy the pressure coming from the degeneracy of fermions. To have solved the TOV equations we need a equation of state that shows how this internal pressure is related to the energy density or mass density. Instead of using politropic equations of state we have solved the equations numericaly using the exact relativistic energy equation for the model of fermion gas at zero temperature. We obtain results for the mass-radius relation for white dwarfs and we compared with the results obtained using the politropic equations of state. In addition we discussed a good fit for the mass-radius relation. (paper)

Influence of Plastic Deformation on Low Temperature Surface Hardening of Austenitic Stainless Steel by Gaseous Nitriding

DEFF Research Database (Denmark)

Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

2015-01-01

This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of two commercial austenitic stainless steels: AISI 304 and EN 1.4369. The materials were plastically deformed to different equivalent strains by uniaxial...... demonstrate that a case of expanded austenite develops and that, in particular, strain-induced martensite has a large influence on the nitrided zone....

Does bone measurement on the radius indicate skeletal status. Concise communication

International Nuclear Information System (INIS)

Mazess, R.B.; Peppler, W.W.; Chesney, R.W.; Lange, T.A.; Lindgren, U.; Smith, E. Jr.

1984-01-01

Single-photon (I-125) absorptiometry was used to measure bone mineral content (BMC) of the distal third of the radius, and dual-photon absorptiometry (Gd-153) was used to measure total-body bone mineral (TBBM), as well as the BMC of major skeletal regions. Measurements were done in normal females, normal males, osteoporotic females, osteoporotic males, and renal patients. The BMC of the radius predicted TBBM well in normal subjects, but was less satisfactory in the patient groups. The spinal BMC was predicted with even lower accuracy from radius measurement. The error in predicting areal density (bone mass per unit projected skeletal area) of the lumbar and thoracic spine from the radius BMC divided by its width was smaller, but the regressions differed significantly among normals, osteoporotics, and renal patients. There was a preferential spinal osteopenia in the osteoporotic group and in about half of the renal patients. Bone measurements on the radius can indicate overall skeletal status in normal subjects and to a lesser degree in patients, but these radius measurements are inaccurate, even on the average, as an indicator of spinal state

33 CFR 165.808 - Corpus Christi Ship Channel, Corpus Christi, TX, safety zone.

Science.gov (United States)

2010-07-01

... Petroleum Gas, the waters within a 500 yard radius of the LPG carrier while the vessel transits the Corpus Christi Ship Channel to the LPG receiving facility. The safety zone remains in effect until the LPG vessel is moored at the LPG receiving facility. (2) For outgoing tank vessels loaded with LPG, the waters...

Microplastics in sea coastal zone: Lessons learned from the Baltic amber.

Science.gov (United States)

Chubarenko, Irina; Stepanova, Natalia

2017-05-01

Baltic amber, adored for its beauty already in Homer's Odyssey (ca. 800 B.C.E), has its material density close to that of wide-spread plastics like polyamide, polystyrene, or acrylic. Migrations of amber stones in the sea and their massive washing ashore have been monitored by Baltic citizens for ages. Based on the collected information, we present the hypothesis on the behaviour of microplastic particles in sea coastal zone. Fresh-to-strong winds generate surface waves, currents and roll-structures, whose joint effect washes ashore from the underwater slope both amber stones and plastics - and carries them back to the sea in a few days. Analysis of underlying hydrophysical processes suggests that sea coastal zone under stormy winds plays a role of a mill for plastics, and negatively buoyant pieces seem to repeatedly migrate between beaches and underwater slopes until they are broken into small enough fragments that can be transported by currents to deeper areas and deposited out of reach of stormy waves. Direct observations on microplastics migrations are urged to prove the hypothesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Crumple zone design for pedestrian protection using impact analysis

Energy Technology Data Exchange (ETDEWEB)

Moon, Hyung Il; Jeon, Young Eun; Kim, Dae Young; Kim, Heon Young [Kangwon National Univ., Chuncheon si (Korea, Republic of); Kim, Yong Soo [Product Development Team, Gyeongsan si (Korea, Republic of)

2012-08-15

This paper describes the design process for an automobile crumple zone for pedestrian protection. The impact load and bending moments predicted by impact analysis were used to design a plastic structure that may help reduce pedestrian injuries to the thigh area. The fracture effect was incorporated into the model by calculating the damage to the plastic material during impact, and the analysis was conducted under the European New Car Assessment Program (Euro NCAP) test conditions, using the upper legform developed by ESI Corporation. In addition, the values predicted by the analysis were validated by comparison with results of actual impact tests.

Crumple zone design for pedestrian protection using impact analysis

International Nuclear Information System (INIS)

Moon, Hyung Il; Jeon, Young Eun; Kim, Dae Young; Kim, Heon Young; Kim, Yong Soo

2012-01-01

This paper describes the design process for an automobile crumple zone for pedestrian protection. The impact load and bending moments predicted by impact analysis were used to design a plastic structure that may help reduce pedestrian injuries to the thigh area. The fracture effect was incorporated into the model by calculating the damage to the plastic material during impact, and the analysis was conducted under the European New Car Assessment Program (Euro NCAP) test conditions, using the upper legform developed by ESI Corporation. In addition, the values predicted by the analysis were validated by comparison with results of actual impact tests

Elastic-plastic analysis of fracture mechanics test specimens. Part 2

International Nuclear Information System (INIS)

Talja, H.; Wallin, K.

1984-12-01

This is second part of the report of the research program 'Comparisons between computational and experimental elastic-plastic results' started at the Technical Research Centre of Finland in 1981. The first part of the research program was reported earlier and contained a two dimensional linear elastic finite element analysis of four specimen geometries (CT, RCT, ASTM-3P and Charpy-V) and testing and elastic-plastic analysis of the specimen (EGF71; 1TCT, material A 542). In this report the second part of the program containing the testing and 2-D elastic-plastic analyses of five specimens is described. The four specimen geometries mentioned above and two different materials (stainless steel AISI 304 and ferrite pressure vessel steel A533B) are considered. The following comparisons are presented in the report: load vs. load displacement curves, J-integral, crack opening displacement (COD), J vs. COD and the size of the plastic zone. The agreement between the computational and experimental results is quite good. Complete agreement can be achieved only with 3-dimensional calculation models. (author)

THE SIZE-VIRIAL RADIUS RELATION OF GALAXIES

International Nuclear Information System (INIS)

Kravtsov, Andrey V.

2013-01-01

I use the abundance matching ansatz, which has proven to be successful in reproducing galaxy clustering and other statistics, to derive estimates of the virial radius, R 200 , for galaxies of different morphological types and a wide range of stellar masses. I show that over eight orders of magnitude in stellar mass galaxies of all morphological types follow an approximately linear relation between half-mass radius of their stellar distribution, r 1/2 , and virial radius, r 1/2 ≈ 0.015 R 200 , with scatter of ≈0.2 dex. Such scaling is in remarkable agreement with the expectation of models that assume that galaxy sizes are controlled by halo angular momentum, r 1/2 ∝λR 200 , where λ is the spin of galaxy parent halo. The scatter about the relation is comparable with the scatter expected from the distribution of λ. Moreover, I show that when the stellar and gas surface density profiles of galaxies of different morphological types are rescaled by the radius r n = 0.015 R 200 , the rescaled profiles follow approximately universal exponential (for late types) and de Vaucouleurs (for early types) form with scatter of only ≈30%-50% at R ≈ 1-3r n . Remarkably, both late- and early-type galaxies have similar mean stellar surface density profiles at R ∼> 1r n . The main difference between their stellar distributions is thus at R n . The results of this study imply that galaxy sizes and radial distribution of baryons are shaped primarily by properties of their parent halos and that the sizes of both late-type disks and early-type spheroids are controlled by halo angular momentum.

33 CFR 165.1151 - Security Zones; liquefied hazardous gas tank vessels, San Pedro Bay, California.

Science.gov (United States)

2010-07-01

... a tank vessel as liquefied petroleum gas, liquefied natural gas, or similar liquefied gas products... Eleventh Coast Guard District § 165.1151 Security Zones; liquefied hazardous gas tank vessels, San Pedro... the sea floor, within a 500 yard radius around any liquefied hazardous gas (LHG) tank vessel that is...

Glass fiber -reinforced plastic tapered poles for transmission and distribution lines: development and experimental study

International Nuclear Information System (INIS)

Ibrahim, S.; Burachysnsky, V.; Polyzois, D.

1999-01-01

A research project to develop lightweight poles for use in power transmission and distribution lines and involving the use of glass fiber-reinforced plastic using the filament winding process is described. Twelve full scale specimen poles were designed, fabricated and subjected to cantilever bending to test failure modes. The test parameters included fiber orientation, ratio of longitudinal-to-circumferential fiber, and the number of layers. Results showed that local buckling was the most dominant failure mode, attributable to the high radius-to-thickness ratio of the specimen poles. Overall, however, these fiber-reinforced plastic poles compared favourably to wooden poles in carrying capacity with significant weight reduction. Lateral displacement at ultimate loads did not exceed the acceptable limit of 10 per cent of the specimen free length. 7 refs., 3 tabs., 2 figs

Root plasticity buffers competition among plants: theory meets experimental data.

Science.gov (United States)

Schiffers, Katja; Tielbörger, Katja; Tietjen, Britta; Jeltsch, Florian

2011-03-01

Morphological plasticity is a striking characteristic of plants in natural communities. In the context of foraging behavior particularly, root plasticity has been documented for numerous species. Root plasticity is known to mitigate competitive interactions by reducing the overlap of the individuals' rhizospheres. But despite its obvious effect on resource acquisition, plasticity has been generally neglected in previous empirical and theoretical studies estimating interaction intensity among plants. In this study, we developed a semi-mechanistic model that addresses this shortcoming by introducing the idea of compensatory growth into the classical-zone-of influence (ZOI) and field-of-neighborhood (FON) approaches. The model parameters describing the belowground plastic sphere of influence (PSI) were parameterized using data from an accompanying field experiment. Measurements of the uptake of a stable nutrient analogue at distinct distances to the neighboring plants showed that the study species responded plastically to belowground competition by avoiding overlap of individuals' rhizospheres. An unexpected finding was that the sphere of influence of the study species Bromus hordeaceus could be best described by a unimodal function of distance to the plant's center and not with a continuously decreasing function as commonly assumed. We employed the parameterized model to investigate the interplay between plasticity and two other important factors determining the intensity of competitive interactions: overall plant density and the distribution of individuals in space. The simulation results confirm that the reduction of competition intensity due to morphological plasticity strongly depends on the spatial structure of the competitive environment. We advocate the use of semi-mechanistic simulations that explicitly consider morphological plasticity to improve our mechanistic understanding of plant interactions.

Marine plastic pollution in waters around Australia: characteristics, concentrations, and pathways.

Directory of Open Access Journals (Sweden)

Julia Reisser

Full Text Available Plastics represent the vast majority of human-made debris present in the oceans. However, their characteristics, accumulation zones, and transport pathways remain poorly assessed. We characterised and estimated the concentration of marine plastics in waters around Australia using surface net tows, and inferred their potential pathways using particle-tracking models and real drifter trajectories. The 839 marine plastics recorded were predominantly small fragments ("microplastics", median length = 2.8 mm, mean length = 4.9 mm resulting from the breakdown of larger objects made of polyethylene and polypropylene (e.g. packaging and fishing items. Mean sea surface plastic concentration was 4256.4 pieces km(-2, and after incorporating the effect of vertical wind mixing, this value increased to 8966.3 pieces km(-2. These plastics appear to be associated with a wide range of ocean currents that connect the sampled sites to their international and domestic sources, including populated areas of Australia's east coast. This study shows that plastic contamination levels in surface waters of Australia are similar to those in the Caribbean Sea and Gulf of Maine, but considerably lower than those found in the subtropical gyres and Mediterranean Sea. Microplastics such as the ones described here have the potential to affect organisms ranging from megafauna to small fish and zooplankton.

Marine Plastic Pollution in Waters around Australia: Characteristics, Concentrations, and Pathways

Science.gov (United States)

Reisser, Julia; Shaw, Jeremy; Wilcox, Chris; Hardesty, Britta Denise; Proietti, Maira; Thums, Michele; Pattiaratchi, Charitha

2013-01-01

Plastics represent the vast majority of human-made debris present in the oceans. However, their characteristics, accumulation zones, and transport pathways remain poorly assessed. We characterised and estimated the concentration of marine plastics in waters around Australia using surface net tows, and inferred their potential pathways using particle-tracking models and real drifter trajectories. The 839 marine plastics recorded were predominantly small fragments (“microplastics”, median length = 2.8 mm, mean length = 4.9 mm) resulting from the breakdown of larger objects made of polyethylene and polypropylene (e.g. packaging and fishing items). Mean sea surface plastic concentration was 4256.4 pieces km−2, and after incorporating the effect of vertical wind mixing, this value increased to 8966.3 pieces km−2. These plastics appear to be associated with a wide range of ocean currents that connect the sampled sites to their international and domestic sources, including populated areas of Australia's east coast. This study shows that plastic contamination levels in surface waters of Australia are similar to those in the Caribbean Sea and Gulf of Maine, but considerably lower than those found in the subtropical gyres and Mediterranean Sea. Microplastics such as the ones described here have the potential to affect organisms ranging from megafauna to small fish and zooplankton. PMID:24312224

Marine plastic pollution in waters around Australia: characteristics, concentrations, and pathways.

Science.gov (United States)

Reisser, Julia; Shaw, Jeremy; Wilcox, Chris; Hardesty, Britta Denise; Proietti, Maira; Thums, Michele; Pattiaratchi, Charitha

2013-01-01

Plastics represent the vast majority of human-made debris present in the oceans. However, their characteristics, accumulation zones, and transport pathways remain poorly assessed. We characterised and estimated the concentration of marine plastics in waters around Australia using surface net tows, and inferred their potential pathways using particle-tracking models and real drifter trajectories. The 839 marine plastics recorded were predominantly small fragments ("microplastics", median length = 2.8 mm, mean length = 4.9 mm) resulting from the breakdown of larger objects made of polyethylene and polypropylene (e.g. packaging and fishing items). Mean sea surface plastic concentration was 4256.4 pieces km(-2), and after incorporating the effect of vertical wind mixing, this value increased to 8966.3 pieces km(-2). These plastics appear to be associated with a wide range of ocean currents that connect the sampled sites to their international and domestic sources, including populated areas of Australia's east coast. This study shows that plastic contamination levels in surface waters of Australia are similar to those in the Caribbean Sea and Gulf of Maine, but considerably lower than those found in the subtropical gyres and Mediterranean Sea. Microplastics such as the ones described here have the potential to affect organisms ranging from megafauna to small fish and zooplankton.

Synthetical optimization of hydraulic radius and acoustic field for thermoacoustic cooler

International Nuclear Information System (INIS)

Kang Huifang; Li Qing; Zhou Gang

2009-01-01

It is well known that the acoustic field and the hydraulic radius of the regenerator play key roles in thermoacoustic processes. The optimization of hydraulic radius strongly depends on the acoustic field in the regenerator. This paper investigates the synthetical optimization of hydraulic radius and acoustic field which is characterized by the ratio of the traveling wave component to the standing wave component. In this paper, we discussed the heat flux, cooling power, temperature gradient and coefficient of performance of thermoacoustic cooler with different combinations of hydraulic radiuses and acoustic fields. The calculation results show that, in the cooler's regenerator, due to the acoustic wave, the heat is transferred towards the pressure antinodes in the pure standing wave, while the heat is transferred in the opposite direction of the wave propagation in the pure traveling wave. The better working condition for the regenerator appears in the traveling wave phase region of the like-standing wave, where the directions of the heat transfer by traveling wave component and standing wave component are the same. Otherwise, the small hydraulic radius is not a good choice for acoustic field with excessively high ratio of traveling wave, and the small hydraulic radius is only needed by the traveling wave phase region of like-standing wave.

Rational functions with maximal radius of absolute monotonicity

KAUST Repository

Loczi, Lajos

2014-05-19

We study the radius of absolute monotonicity R of rational functions with numerator and denominator of degree s that approximate the exponential function to order p. Such functions arise in the application of implicit s-stage, order p Runge-Kutta methods for initial value problems and the radius of absolute monotonicity governs the numerical preservation of properties like positivity and maximum-norm contractivity. We construct a function with p=2 and R>2s, disproving a conjecture of van de Griend and Kraaijevanger. We determine the maximum attainable radius for functions in several one-parameter families of rational functions. Moreover, we prove earlier conjectured optimal radii in some families with 2 or 3 parameters via uniqueness arguments for systems of polynomial inequalities. Our results also prove the optimality of some strong stability preserving implicit and singly diagonally implicit Runge-Kutta methods. Whereas previous results in this area were primarily numerical, we give all constants as exact algebraic numbers.

Modelling accumulation of marine plastics in the coastal zone; what are the dominant physical processes?

Science.gov (United States)

Critchell, Kay; Lambrechts, Jonathan

2016-03-01

Anthropogenic marine debris, mainly of plastic origin, is accumulating in estuarine and coastal environments around the world causing damage to fauna, flora and habitats. Plastics also have the potential to accumulate in the food web, as well as causing economic losses to tourism and sea-going industries. If we are to manage this increasing threat, we must first understand where debris is accumulating and why these locations are different to others that do not accumulate large amounts of marine debris. This paper demonstrates an advection-diffusion model that includes beaching, settling, resuspension/re-floating, degradation and topographic effects on the wind in nearshore waters to quantify the relative importance of these physical processes governing plastic debris accumulation. The aim of this paper is to prioritise research that will improve modelling outputs in the future. We have found that the physical characteristic of the source location has by far the largest effect on the fate of the debris. The diffusivity, used to parameterise the sub-grid scale movements, and the relationship between debris resuspension/re-floating from beaches and the wind shadow created by high islands also has a dramatic impact on the modelling results. The rate of degradation of macroplastics into microplastics also have a large influence in the result of the modelling. The other processes presented (settling, wind drift velocity) also help determine the fate of debris, but to a lesser degree. These findings may help prioritise research on physical processes that affect plastic accumulation, leading to more accurate modelling, and subsequently management in the future.

Brittle-ductile gliding shear zone and its dynamic metallization in uranium deposit No. 3110

International Nuclear Information System (INIS)

Fang Shiyi.

1990-01-01

A preliminary study on the macroscopic geological structure, microstructures of plastic deformation rotary strain, structural geochemistry and zoning regularity of a brittle-ductile gliding shear zone in uranium deposit No. 3110 is made. Structural dynamic metallization of uranium caused by the strong shearing stress is discussed. It is pointed out that great attention must be paid to in further exploration

Studying the proton 'radius' puzzle with μp elastic scattering

International Nuclear Information System (INIS)

Gilman, R.

2013-01-01

The disagreement between the proton radius determined from muonic hydrogen and from electronic measurements is called the proton radius puzzle. The resolution of the puzzle remains unclear and appears to require new experimental results. An experiment to measure muon-proton elastic scattering is presented here

Improved airline-type supplied-air plastic suit. [For personnel protection against inhalation of airborne plutonium and tritium

Energy Technology Data Exchange (ETDEWEB)

Jolley, L. Jr.; Zippler, D.B.; Cofer, C.H.; Harper, J.A.

1978-06-01

Two piece supplied-air plastic suits are used extensively at the Savannah River Plant for personnel protection against inhalation of airborne plutonium and tritium. Worker comfort and noise level problems gave impetus to development of an improved suit and aid distribution system. The resulting plastic suit and development work are discussed. The plastic suit unit cost is less than $20, the hearing zone noise level is less than 75 dBA, protection factors exceed 10,000, and user comfort is approved. This suit is expected to meet performance requirements for unrestricted use.

Spectral Radius and Hamiltonicity of Graphs

Czech Academy of Sciences Publication Activity Database

Fiedler, Miroslav; Nikiforov, V.

2010-01-01

Roč. 432, č. 9 (2010), s. 2170-2173 ISSN 0024-3795 Institutional research plan: CEZ:AV0Z10300504 Keywords : Hamiltonian cycle * Hamiltonian path * spectral radius Subject RIV: BA - General Mathematics Impact factor: 1.005, year: 2010

Solar Radius at Subterahertz Frequencies and Its Relation to Solar Activity

Science.gov (United States)

Menezes, Fabian; Valio, Adriana

2017-12-01

The Sun emits radiation at several wavelengths of the electromagnetic spectrum. In the optical band, the solar radius is 695 700 km, and this defines the photosphere, which is the visible surface of the Sun. However, as the altitude increases, the electromagnetic radiation is produced at other frequencies, causing the solar radius to change as a function of wavelength. These measurements enable a better understanding of the solar atmosphere, and the radius dependence on the solar cycle is a good indicator of the changes that occur in the atmospheric structure. We measure the solar radius at the subterahertz frequencies of 0.212 and 0.405 THz, which is the altitude at which these emissions are primarily generated, and also analyze the radius variation over the 11-year solar activity cycle. For this, we used radio maps of the solar disk for the period between 1999 and 2017, reconstructed from daily scans made by the Solar Submillimeter-wave Telescope (SST), installed at El Leoncito Astronomical Complex (CASLEO) in the Argentinean Andes. Our measurements yield radii of 966.5'' ±2.8'' for 0.2 THz and 966.5'' ±2.7'' for 0.4 THz. This implies a height of 5.0 ±2.0 ×106 m above the photosphere. Furthermore, we also observed a strong anticorrelation between the radius variation and the solar activity at both frequencies.

Thoughts on the so-called 'radius-capitellum axis'

International Nuclear Information System (INIS)

Schild, H.; Mueller, H.A.; Wagner, H.; Baetz, W.; Mainz Univ.

1982-01-01

We have studied 438 patients radiologically in order to observe the so-called 'radius-capitellum axis'. In about a quarter of people with normal elbows the axis passes lateral to the middle portion of the capitellum, so that even when there is marked deviation, there is no certainty that the humero-radial joint is abnormal. Deviation of the axis can be caused by changes in the shape of the capitellum or of the radius, or by distension of the capsule of the elbow joint, or by various changes in muscular pull. (orig.) [de

Thoughts on the so-called radius-capitellum axis

Energy Technology Data Exchange (ETDEWEB)

Schild, H; Mueller, H A; Wagner, H; Baetz, W

1982-02-01

We have studied 438 patients radiologically in order to observe the so-called 'radius-capitellum axis'. In about a quarter of people with normal elbows the axis passes lateral to the middle portion of the capitellum, so that even when there is marked deviation, there is no certainty that the humero-radial joint is abnormal. Deviation of the axis can be caused by changes in the shape of the capitellum or of the radius, or by distension of the capsule of the elbow joint, or by various changes in muscular pull.

The PRad experiment and the proton radius puzzle

Directory of Open Access Journals (Sweden)

Gasparian Ashot

2014-06-01

Full Text Available New results from the recent muonic hydrogen experiments seriously questioned our knowledge of the proton charge radius, rp. The new value, with its unprecedented less than sub-percent precision, is currently up to eight standard deviation smaller than the average value from all previous experiments, triggering the well-known “proton charge radius puzzle” in nuclear and atomic physics. The PRad collaboration is currently preparing a novel, magnetic-spectrometer-free ep scattering experiment in Hall B at JLab for a new independent rp measurement to address this growing “puzzle” in physics.

Underground nuclear explosions. Study of the cavity radius

International Nuclear Information System (INIS)

Michaud, L.

1968-11-01

An underground nuclear explosion creates a cavity due to the expansion of the surrounding medium vaporized by the shot. The cavity radius is related to the energy of explosion and to the overburden pressure of the medium. The introduction of new elements such as the environment of the device (in a deep hole or in a tunnel) and the cohesion of the medium leads to a relationship which determines this radius. The known French and American underground explosions performed in various media, energy and overburden conditions, satisfy this relationship with a good precision. (author) [fr

Mass-Radius Relations of Z and Higgs-Like Bosons

Directory of Open Access Journals (Sweden)

Lehnert B.

2014-01-01

Full Text Available Relations between the rest mass and the effective radius are deduced for the Z boson and the experimentally discovered Higgs-like boson, in terms of a revised quantum electrodynamic (RQED theory. The latter forms an alternative to the Standard Model of elementary particles. This results in an effective radius of the order of 10 E-18 m for a rest mass of 125 GeV.

On joint numerical radius II

Czech Academy of Sciences Publication Activity Database

Drnovšek, R.; Müller, Vladimír

2014-01-01

Roč. 62, č. 9 (2014), s. 1197-1204 ISSN 0308-1087 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional support: RVO:67985840 Keywords : joint numerical range * numerical radius Subject RIV: BA - General Mathematics Impact factor: 0.738, year: 2014 http://www.tandfonline.com/doi/abs/10.1080/03081087.2013.816303

Thin Fresnel zone plate lenses for focusing underwater sound

International Nuclear Information System (INIS)

Calvo, David C.; Thangawng, Abel L.; Nicholas, Michael; Layman, Christopher N.

2015-01-01

A Fresnel zone plate (FZP) lens of the Soret type creates a focus by constructive interference of waves diffracted through open annular zones in an opaque screen. For underwater sound below MHz frequencies, a large FZP that blocks sound using high-impedance, dense materials would have practical disadvantages. We experimentally and numerically investigate an alternative approach of creating a FZP with thin (0.4λ) acoustically opaque zones made of soft silicone rubber foam attached to a thin (0.1λ) transparent rubber substrate. An ultra-thin (0.0068λ) FZP that achieves higher gain is also proposed and simulated which uses low-volume fraction, bubble-like resonant air ring cavities to construct opaque zones. Laboratory measurements at 200 kHz indicate that the rubber foam can be accurately modeled as a lossy fluid with an acoustic impedance approximately 1/10 that of water. Measured focal gains up to 20 dB agree with theoretical predictions for normal and oblique incidence. The measured focal radius of 0.68λ (peak-to-null) agrees with the Rayleigh diffraction limit prediction of 0.61 λ/NA (NA = 0.88) for a low-aberration lens

Variable radius cartography - History and perspectives of a new discipline

Science.gov (United States)

Scalera, Giancarlo

2014-05-01

The map that Toscanelli sent to Columbus was an unconscious application of cartography at a smaller radius than the real. The first really conscious attempts to represent the geography of Earth on globes of radius less than the current one occurred after the formulation of the concept of expanding Earth through geological time. The American chemist and geologist Richard Owen (1810-1890) in his book Key to the geology of the globe (1857) described the principles of what he himself called Anatomical Geology, with the Earth growing as a biological organism. The book contained a global paleogeographic map of the Earth that would have had a radius of about 4000 kilometers. In 1928 J.A.H. Kerkhoff (under the pseudonym Aero-dilettant) published a series of paleogeographic globes on which the modern oceans disappeared. With the same artisan methods of transfer continental outlines from a sphere to a smaller one, in 1933 O.C. Hilgenberg represented three different geological epochs, and, later, for the first time mapped paleopoles with their site-pole segments of meridian. Even today the traditional method of Hilgenberg is followed by senior researchers (Klaus Vogel, 2003) and younger geologists (James Maxlow). In England Hugh Owen applied the methods of traditional cartography to the variable radius one. His Atlas of Continental Displacement was in the 70s and 80s, for this discipline, a real milestone. While in the field of constant radius paleogeography the adherents to plate tectonics created many computer codes of automatic mapping (Bullard et al., 1965; Smith & Hallam, 1970; Scotese et al., 1979; and many others), in the variable radius field few tried to reach the same task. In 1972 in United States a first very simple attempt (but was not further developed) came from a private, R.B. Perry, followed by the still not-computerized Atlas of Owen, and both them constituted inspiration for the construction of a FORTRAN variable radius mapping code at INGV, with which it

Social Support Contributes to Outcomes following Distal Radius Fractures

Directory of Open Access Journals (Sweden)

Caitlin J. Symonette

2013-01-01

Full Text Available Background. Distal radius fractures are the most common fracture of the upper extremity and cause variable disability. This study examined the role of social support in patient-reported pain and disability at one year following distal radius fracture. Methods. The Medical Outcomes Study Social Support Survey was administered to a prospective cohort of 291 subjects with distal radius fractures at their baseline visit. Pearson correlations and stepwise linear regression models (F-to-remove 0.10 were used to identify whether social support contributes to wrist fracture outcomes. The primary outcome of pain and disability at one year was measured using the Patient Rated Wrist Evaluation. Results. Most injuries were low energy (67.5% and were treated nonoperatively (71.9%. Pearson correlation analysis revealed that higher reported social support correlated with improved Patient Rated Wrist Evaluation scores at 1 year, r(n=181=-0.22, P<0.05. Of the subscales within the Social Support Survey, emotional/informational support explained a significant proportion of the variance in 1-year Patient Rated Wrist Evaluation scores, R2=4.7%, F (1, 181 = 9.98, P<0.05. Conclusion. Lower emotional/informational social support at the time of distal radius fracture contributes a small but significant percentage to patient-reported pain and disability outcomes.

Odours from marine plastic debris induce food search behaviours in a forage fish.

Science.gov (United States)

Savoca, Matthew S; Tyson, Chris W; McGill, Michael; Slager, Christina J

2017-08-16

Plastic pollution is an anthropogenic stressor in marine ecosystems globally. Many species of marine fish (more than 50) ingest plastic debris. Ingested plastic has a variety of lethal and sublethal impacts and can be a route for bioaccumulation of toxic compounds throughout the food web. Despite its pervasiveness and severity, our mechanistic understanding of this maladaptive foraging behaviour is incomplete. Recent evidence suggests that the chemical signature of plastic debris may explain why certain species are predisposed to mistaking plastic for food. Anchovy ( Engraulis sp.) are abundant forage fish in coastal upwelling systems and a critical prey resource for top predators. Anchovy ingest plastic in natural conditions, though the mechanism they use to misidentify plastic as prey is unknown. Here, we presented wild-caught schools of northern anchovy ( Engraulis mordax ) with odour solutions made of plastic debris and clean plastic to compare school-wide aggregation and rheotactic responses relative to food and food odour presentations. Anchovy schools responded to plastic debris odour with increased aggregation and reduced rheotaxis. These results were similar to the effects food and food odour presentations had on schools. Conversely, these behavioural responses were absent in clean plastic and control treatments. To our knowledge, this is the first experimental evidence that adult anchovy use odours to forage. We conclude that the chemical signature plastic debris acquires in the photic zone can induce foraging behaviours in anchovy schools. These findings provide further support for a chemosensory mechanism underlying plastic consumption by marine wildlife. Given the trophic position of forage fish, these findings have considerable implications for aquatic food webs and possibly human health. © 2017 The Author(s).

Effects of corner radius on periodic nanoantenna for surface-enhanced Raman spectroscopy

International Nuclear Information System (INIS)

Chao, Bo-Kai; Lin, Shih-Che; Nien, Li-Wei; Hsueh, Chun-Hway; Li, Jia-Han

2015-01-01

Corner radius is a concept to approximate the fabrication limitation due to the effective beam broadening at the corner in using electron-beam lithography. The purpose of the present study is to investigate the effects of corner radius on the electromagnetic field enhancement and resonance wavelength for three periodic polygon dimers of bowtie, twin square, and twin pentagon. The enhancement factor of surface-enhanced Raman spectroscopy due to the localized surface plasmon resonances in fabricated gold bowtie nanostructures was investigated using both Raman spectroscopy and finite-difference time-domain simulations. The simulated enhancement factor versus corner radius relation was in agreement with measurements and it could be fitted by a power-law relation. In addition, the resonance wavelength showed blue shift with the increasing corner radius because of the distribution of concentrated charges in a larger area. For different polygons, the corner radius instead of the tip angle is the dominant factor of the electromagnetic field enhancement because the surface charges tend to localize at the corner. Greater enhancements can be obtained by having both the smaller gap and sharper corner although the corner radius effect on intensity enhancement is less than the gap size effect. (paper)

The separatrix radius measurement of field-reversed configuration plasma in FRX-L

International Nuclear Information System (INIS)

Zhang, Shouyin; Tejero, Erik M.; Taccetti, Jose Martin; Wurden, Glen A.; Intrator, Thomas; Waganaar, William J.

2004-01-01

Magnetic pick-up coils and single turn flux loops are installed on the FRX-L device. The combination of the two measurements provides the excluded flux radius that approximates the separatrix radius of the field-reversed configuration plasma. Arrays of similar probes are used to map out local magnetic field dynamics beyond both ends of the theta-coil confinement region to help understand the effects of cusp locations on flux trapping during the FRC formation process. Details on the probe design and system calibrations are presented. The overall system calibration of excluded flux radius measurement is examined by replacing FRC plasma with a known radius aluminum conductor cylinder.

The radius of the quiescent neutron star in the globular cluster M13

Science.gov (United States)

Shaw, A. W.; Heinke, C. O.; Steiner, A. W.; Campana, S.; Cohn, H. N.; Ho, W. C. G.; Lugger, P. M.; Servillat, M.

2018-06-01

X-ray spectra of quiescent low-mass X-ray binaries containing neutron stars can be fit with atmosphere models to constrain the mass and the radius. Mass-radius constraints can be used to place limits on the equation of state of dense matter. We perform fits to the X-ray spectrum of a quiescent neutron star in the globular cluster M13, utilizing data from ROSAT, Chandra, and XMM-Newton, and constrain the mass-radius relation. Assuming an atmosphere composed of hydrogen and a 1.4 M⊙ neutron star, we find the radius to be R_NS=12.2^{+1.5}_{-1.1} km, a significant improvement in precision over previous measurements. Incorporating an uncertainty on the distance to M13 relaxes the radius constraints slightly and we find R_NS=12.3^{+1.9}_{-1.7} km (for a 1.4M⊙ neutron star with a hydrogen atmosphere), which is still an improvement in precision over previous measurements, some of which do not consider distance uncertainty. We also discuss how the composition of the atmosphere affects the derived radius, finding that a helium atmosphere implies a significantly larger radius.

Plastics and microplastics in the oceans: From emerging pollutants to emerged threat.

Science.gov (United States)

Avio, Carlo Giacomo; Gorbi, Stefania; Regoli, Francesco

2017-07-01

Plastic production has increased dramatically worldwide over the last 60 years and it is nowadays recognized as a serious threat to the marine environment. Plastic pollution is ubiquitous, but quantitative estimates on the global abundance and weight of floating plastics are still limited, particularly for the Southern Hemisphere and the more remote regions. Some large-scale convergence zones of plastic debris have been identified, but there is the urgency to standardize common methodologies to measure and quantify plastics in seawater and sediments. Investigations on temporal trends, geographical distribution and global cycle of plastics have management implications when defining the origin, possible drifting tracks and ecological consequences of such pollution. An elevated number of marine species is known to be affected by plastic contamination, and a more integrated ecological risk assessment of these materials has become a research priority. Beside entanglement and ingestion of macro debris by large vertebrates, microplastics are accumulated by planktonic and invertebrate organisms, being transferred along food chains. Negative consequences include loss of nutritional value of diet, physical damages, exposure to pathogens and transport of alien species. In addition, plastics contain chemical additives and efficiently adsorb several environmental contaminants, thus representing a potential source of exposure to such compounds after ingestion. Complex ecotoxicological effects are increasingly reported, but the fate and impact of microplastics in the marine environment are still far to be fully clarified. Copyright © 2016 Elsevier Ltd. All rights reserved.

A New Paradigm For Modeling Fault Zone Inelasticity: A Multiscale Continuum Framework Incorporating Spontaneous Localization and Grain Fragmentation.

Science.gov (United States)

Elbanna, A. E.

2015-12-01

The brittle portion of the crust contains structural features such as faults, jogs, joints, bends and cataclastic zones that span a wide range of length scales. These features may have a profound effect on earthquake nucleation, propagation and arrest. Incorporating these existing features in modeling and the ability to spontaneously generate new one in response to earthquake loading is crucial for predicting seismicity patterns, distribution of aftershocks and nucleation sites, earthquakes arrest mechanisms, and topological changes in the seismogenic zone structure. Here, we report on our efforts in modeling two important mechanisms contributing to the evolution of fault zone topology: (1) Grain comminution at the submeter scale, and (2) Secondary faulting/plasticity at the scale of few to hundreds of meters. We use the finite element software Abaqus to model the dynamic rupture. The constitutive response of the fault zone is modeled using the Shear Transformation Zone theory, a non-equilibrium statistical thermodynamic framework for modeling plastic deformation and localization in amorphous materials such as fault gouge. The gouge layer is modeled as 2D plane strain region with a finite thickness and heterogeenous distribution of porosity. By coupling the amorphous gouge with the surrounding elastic bulk, the model introduces a set of novel features that go beyond the state of the art. These include: (1) self-consistent rate dependent plasticity with a physically-motivated set of internal variables, (2) non-locality that alleviates mesh dependence of shear band formation, (3) spontaneous evolution of fault roughness and its strike which affects ground motion generation and the local stress fields, and (4) spontaneous evolution of grain size and fault zone fabric.

Sub-100 nm hard X-ray microbeam generation with Fresnel zone plate optics

CERN Document Server

Takano, H; Takeuchi, A

2003-01-01

A hard X-ray focusing test of a Fresnel zone plate has been performed with a synchrotron radiation source at the undulator beamline 20XU of SPring-8. Fresnel zone plate with a radius of 150 mu m, and an outermost zone width of 100 nm was used for the X-ray focusing device. The 248-m-long beamline provides fully coherent illumination for the focusing device. The focused beam evaluated by the knife-edge-scan method and scanning microscope test using test charts. Nearly diffraction- limited focusing with a size of 120 nm was achieved for the first-order diffraction at 10 keV X-ray. Evaluation for the third order diffraction was also performed at 8 keV X-ray, and a focal size of 50 m has been obtained. (author)

Elasto-plastic analysis using an efficient formulation of the finite element method

International Nuclear Information System (INIS)

Aamodt, B.; Mo, O.

1975-01-01

Based on the flow theory of plasticity, the von Mises or the Tresca yield criterion and the isotropic hardening law, an incremental stiffness relationship can be established for a finite element model of the elasto-plastic structure. However, instead of including all degrees of freedom and all finite elements of the total model in a nonlinear solution process, a separation of elastic and plastic parts of the structure can be carried out. Such a separation can be obtained by identifying elastic parts of the structure as 'elastic' superelements and elasto-plastic parts of the structure as 'elasto-plastic' superelements. Also, it may be of advantage to use several levels of superelements in modelling the elastic parts of the structure. The solution of the nonlinear equations is performed utilizing a combination of load incrementation and equilibrium iterations. In this connection, a comparative numerical study of the Newton-Raphson iteration scheme, the initial stress method, and modified Newton-Raphson iteration schemes is presented. The present method of analysis is demonstrated for two larger examples of elasto-plastic analysis. Firstly, an elasto-plastic analysis of a plate with a central hole and subjected to tensile forces is carried out. The results are compared with experimental values. Secondly, a three dimensional analysis of a thick plate with a central through-crack subjected to tensile forces is considered. The variation through the plate thickness of the size of the plastic zones at the crack tip is studied. The numerical examples show that the present method is a powerful and efficient tool in elasto-plastic analysis

77 FR 69789 - Foreign-Trade Zone 171-Liberty County, TX; Application for Reorganization/Expansion Under...

Science.gov (United States)

2012-11-21

... zones and can permit significantly greater flexibility in the designation of new subzones or ``usage..., Highway FM 787, Liberty; Site 5 (583.081 acres)--Sjolander Plastics Storage Railyard facility, adjacent to...

Plasticity theory

CERN Document Server

Lubliner, Jacob

2008-01-01

The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

An Earth-sized planet in the habitable zone of a cool star.

Science.gov (United States)

Quintana, Elisa V; Barclay, Thomas; Raymond, Sean N; Rowe, Jason F; Bolmont, Emeline; Caldwell, Douglas A; Howell, Steve B; Kane, Stephen R; Huber, Daniel; Crepp, Justin R; Lissauer, Jack J; Ciardi, David R; Coughlin, Jeffrey L; Everett, Mark E; Henze, Christopher E; Horch, Elliott; Isaacson, Howard; Ford, Eric B; Adams, Fred C; Still, Martin; Hunter, Roger C; Quarles, Billy; Selsis, Franck

2014-04-18

The quest for Earth-like planets is a major focus of current exoplanet research. Although planets that are Earth-sized and smaller have been detected, these planets reside in orbits that are too close to their host star to allow liquid water on their surfaces. We present the detection of Kepler-186f, a 1.11 ± 0.14 Earth-radius planet that is the outermost of five planets, all roughly Earth-sized, that transit a 0.47 ± 0.05 solar-radius star. The intensity and spectrum of the star's radiation place Kepler-186f in the stellar habitable zone, implying that if Kepler-186f has an Earth-like atmosphere and water at its surface, then some of this water is likely to be in liquid form.

Fatigue crack Behaviour in a High Strength Tool Steel

DEFF Research Database (Denmark)

Højerslev, Christian; Carstensen, Jesper V.; Brøndsted, Povl

2002-01-01

The influence of microstructure on fatigue crack initiation and crack growth of a hardened and tempered high speed steel was investigated. The evolution of fatigue cracks was followed in four point bending at room temperature. It was found that a carbide damage zone exists above a threshold load...... value of maximally 80% of the yield strength of the steel. The size of this carbide damage zone increases with increasing load amplitude, and the zone is apparently associated with crack nucleation. On fatigue crack propagation plastic deformation of the matrix occurs in a radius of approximately 4...... microns in front of the fatigue crack tip, which is comparable with the relevant mean free carbide spacing....

Localization of plastic yield and fracture mechanism in high-strength niobium alloy with ultra-fine particles of non-metallic phase

International Nuclear Information System (INIS)

Tyumentsev, A.N.; Gonchikov, V.Ch.; Korotaev, A.D.; Pinzhin, Yu.P.; Tyumentseva, S.F.

1989-01-01

The regularities of localization of plastic flow in high-strength dispersion-strengthened niobium alloy are studied. On the basis of investigations of the microstructure of strain localization zones the mechanism of stability losses of plastic flow including, the processes of diffusion of nonequilibrium vacancies in fields of nonuniform stresses, is proposed. The role of diffuse strain mechanisms during reorientation of the crystalline lattice is discussed. The regularities of fracture of high-strength alloy under conditions of rotational-shift instability of plastic flow are investigated

The influence of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices

International Nuclear Information System (INIS)

Idris, A; Pullen, K

2013-01-01

The effects of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices are presented in this paper. Both experimental and CFD results show that chamfering and corner radiusing improve the discharge coefficient of rotating orifices. For non-inclined rotating orifices, the discharge coefficient reduces with increasing speed, but chamfered and radiused orifices manage to have higher discharge coefficient (C d ) than the straight edge orifices. Comparing between chamfering and corner radiusing, the radiused corner orifice has the highest C d at every rotational speed. This is because the inlet radius helps guiding the flow into the orifice and avoiding flow separation at the inlet.

On the determination of the proton RMS-radius from electron scattering data

International Nuclear Information System (INIS)

Borkowski, F.; Simon, G.G.; Walther, V.H.; Wendling, R.D.

1975-01-01

It is shown that the proton rms radius should be determined from fiting a polynomial of second order to the low-q 2 form factors. The commonly used polynomial of first yields radius values which are too small. The proton rms radius has been redetermined from an analysis of the electron scattering data measured at three laboratories. The best fit value is [r 2 sub(E)]sup(1/2) = 0.87 +- 0.02 fm. (orig.) [de

A SUPER-EARTH-SIZED PLANET ORBITING IN OR NEAR THE HABITABLE ZONE AROUND A SUN-LIKE STAR

Energy Technology Data Exchange (ETDEWEB)

Barclay, Thomas; Burke, Christopher J.; Howell, Steve B.; Rowe, Jason F.; Huber, Daniel; Jenkins, Jon M.; Quintana, Elisa V.; Still, Martin; Twicken, Joseph D.; Bryson, Stephen T.; Borucki, William J.; Caldwell, Douglas A.; Clarke, Bruce D.; Christiansen, Jessie L; Coughlin, Jeffrey L. [NASA Ames Research Center, M/S 244-30, Moffett Field, CA 94035 (United States); Isaacson, Howard; Kolbl, Rea; Marcy, Geoffrey W. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Ciardi, David [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); and others

2013-05-10

We present the discovery of a super-Earth-sized planet in or near the habitable zone of a Sun-like star. The host is Kepler-69, a 13.7 mag G4V-type star. We detect two periodic sets of transit signals in the 3-year flux time series of Kepler-69, obtained with the Kepler spacecraft. Using the very high precision Kepler photometry, and follow-up observations, our confidence that these signals represent planetary transits is >99.3%. The inner planet, Kepler-69b, has a radius of 2.24{sup +0.44}{sub -0.29} R{sub Circled-Plus} and orbits the host star every 13.7 days. The outer planet, Kepler-69c, is a super-Earth-sized object with a radius of 1.7{sup +0.34}{sub -0.23} R{sub Circled-Plus} and an orbital period of 242.5 days. Assuming an Earth-like Bond albedo, Kepler-69c has an equilibrium temperature of 299 {+-} 19 K, which places the planet close to the habitable zone around the host star. This is the smallest planet found by Kepler to be orbiting in or near the habitable zone of a Sun-like star and represents an important step on the path to finding the first true Earth analog.

Comparison of plastic, high density carbon, and beryllium as indirect drive NIF ablators

Science.gov (United States)

Kritcher, A. L.; Clark, D.; Haan, S.; Yi, S. A.; Zylstra, A. B.; Callahan, D. A.; Hinkel, D. E.; Berzak Hopkins, L. F.; Hurricane, O. A.; Landen, O. L.; MacLaren, S. A.; Meezan, N. B.; Patel, P. K.; Ralph, J.; Thomas, C. A.; Town, R.; Edwards, M. J.

2018-05-01

Detailed radiation hydrodynamic simulations calibrated to experimental data have been used to compare the relative strengths and weaknesses of three candidate indirect drive ablator materials now tested at the NIF: plastic, high density carbon or diamond, and beryllium. We apply a common simulation methodology to several currently fielded ablator platforms to benchmark the model and extrapolate designs to the full NIF envelope to compare on a more equal footing. This paper focuses on modeling of the hohlraum energetics which accurately reproduced measured changes in symmetry when changes to the hohlraum environment were made within a given platform. Calculations suggest that all three ablator materials can achieve a symmetric implosion at a capsule outer radius of ˜1100 μm, a laser energy of 1.8 MJ, and a DT ice mass of 185 μg. However, there is more uncertainty in the symmetry predictions for the plastic and beryllium designs. Scaled diamond designs had the most calculated margin for achieving symmetry and the highest fuel absorbed energy at the same scale compared to plastic or beryllium. A comparison of the relative hydrodynamic stability was made using ultra-high resolution capsule simulations and the two dimensional radiation fluxes described in this work [Clark et al., Phys. Plasmas 25, 032703 (2018)]. These simulations, which include low and high mode perturbations, suggest that diamond is currently the most promising for achieving higher yields in the near future followed by plastic, and more data are required to understand beryllium.

Magical Engineering Plastic

Energy Technology Data Exchange (ETDEWEB)

Kim, Gwang Ung

1988-01-15

This book introduces engineering plastic about advantage of engineering plastic, plastic material from processing method, plastic shock, plastic until now, background of making of engineering plastic, wonderful engineering plastic science such as a high molecule and molecule, classification of high molecule, difference between metal and high molecule, heat and high molecule materials, and property of surface, engineering plastic of dream like from linseed oil to aramid, small dictionary of engineering plastic.

Magical Engineering Plastic

International Nuclear Information System (INIS)

Kim, Gwang Ung

1988-01-01

This book introduces engineering plastic about advantage of engineering plastic, plastic material from processing method, plastic shock, plastic until now, background of making of engineering plastic, wonderful engineering plastic science such as a high molecule and molecule, classification of high molecule, difference between metal and high molecule, heat and high molecule materials, and property of surface, engineering plastic of dream like from linseed oil to aramid, small dictionary of engineering plastic.

Dead Zones in LX-17 and PBX 9502

Energy Technology Data Exchange (ETDEWEB)

Souers, P C; Andreski, H G; Batteux, J; Bratton, B; Cabacungan, C; Cook, III, C F; Fletcher, S; Garza, R; Grimsley, D; Handly, J; Hernandez, A; McMaster, P; Molitoris, J D; Palmer, R; Prindiville, J; Rodriguez, J; Schneberk, D; Wong, B; Vitello, P

2005-09-06

Pin and X-ray corner-turning data have been taken on ambient LX-17 and PBX 9052, and the results are listed in tables as an aid to future modeling. The results have been modeled at 4 zones/mm with a reactive flow approach that varies the burn rate as a function of pressure. A single rate format is used to simulate failure and detonation in different pressure regimes. A pressure cut-off must also be reached to initiate the burn. Corner-turning and failure are modeled using an intermediate pressure rate region, and detonation occurs at high pressure. The TATB booster is also modeled using reactive flow, and X-ray tomography is used to partition the ram-pressed hemisphere into five different density regions. The model reasonably fits the bare corner-turning experiment but predicts a smaller dead zone with steel confinement, in contradiction with experiment. The same model also calculates the confined and unconfined cylinder detonation velocities and predicts the failure of the unconfined cylinder at 3.75 mm radius. The PBX 9502 shows a smaller dead zone than LX-17. An old experiment that showed a large apparent dead zone in Comp B was repeated with X-ray transmission and no dead zone was seen. This confirms the idea that a variable burn rate is the key to modeling. The model also produces initiation delays, which are shorter than those found in time-to-detonation.

Modelling of HTR (High Temperature Reactor Pebble-Bed 10 MW to Determine Criticality as A Variations of Enrichment and Radius of the Fuel (Kernel With the Monte Carlo Code MCNP4C

Directory of Open Access Journals (Sweden)

Hammam Oktajianto

2014-12-01

Full Text Available Gas-cooled nuclear reactor is a Generation IV reactor which has been receiving significant attention due to many desired characteristics such as inherent safety, modularity, relatively low cost, short construction period, and easy financing. High temperature reactor (HTR pebble-bed as one of type of gas-cooled reactor concept is getting attention. In HTR pebble-bed design, radius and enrichment of the fuel kernel are the key parameter that can be chosen freely to determine the desired value of criticality. This paper models HTR pebble-bed 10 MW and determines an effective of enrichment and radius of the fuel (Kernel to get criticality value of reactor. The TRISO particle coated fuel particle which was modelled explicitly and distributed in the fuelled region of the fuel pebbles using a Simple-Cubic (SC lattice. The pebble-bed balls and moderator balls distributed in the core zone using a Body-Centred Cubic lattice with assumption of a fresh fuel by the fuel enrichment was 7-17% at 1% range and the size of the fuel radius was 175-300 µm at 25 µm ranges. The geometrical model of the full reactor is obtained by using lattice and universe facilities provided by MCNP4C. The details of model are discussed with necessary simplifications. Criticality calculations were conducted by Monte Carlo transport code MCNP4C and continuous energy nuclear data library ENDF/B-VI. From calculation results can be concluded that an effective of enrichment and radius of fuel (Kernel to achieve a critical condition was the enrichment of 15-17% at a radius of 200 µm, the enrichment of 13-17% at a radius of 225 µm, the enrichments of 12-15% at radius of 250 µm, the enrichments of 11-14% at a radius of 275 µm and the enrichment of 10-13% at a radius of 300 µm, so that the effective of enrichments and radii of fuel (Kernel can be considered in the HTR 10 MW. Keywords—MCNP4C, HTR, enrichment, radius, criticality 

An online review of plastic surgeons in southern California.

Science.gov (United States)

Lewis, Priya; Kobayashi, Emily; Gupta, Subhas

2015-05-01

It has become commonplace for patients to access online reviews of physicians when making choices about health care, just as any consumer would in today's computer-dependent world. Previous studies have shown that online reviews of physicians are generally positive. However, 1 negative review has the potential to adversely affect business and reputations. To characterize the online presence of plastic surgeons in Southern California as portrayed by physician rating websites (PRWs). An extensive online database of board-certified plastic surgeons was used to generate a list of surgeons within a 50-mile radius of Pomona, CA. Ratings from the PRWs HealthGrades.com, Vitals.com, and UCompareHealthcare.com were cataloged by number of reviews and ratings. Two hundred sixty-three surgeons were evaluated with the most-represented cities being Beverly Hills (N=47), Los Angeles (N=31), and Newport Beach (N=27). Ninety-seven percent of the surgeons were rated on at least 1 of the 3 PRWs chosen. In general, surgeons were rated highly, with a mean rating of 85%, SD, 14% (Ponline ratings ranged from 0 to 222 per surgeon. The median number of total reviews was 25 and the mean rating for those surgeons above and below the median were equivocal, at 86% and 85%, respectively (P=0.284). In this study, we found that plastic surgeons in Southern California have an online presence that can be influenced by their patients; they should be aware of this and conscious of their online reputations. Overall, the ratings were high, regardless of the number of reviews.

International policies to reduce plastic marine pollution from single-use plastics (plastic bags and microbeads): A review.

Science.gov (United States)

Xanthos, Dirk; Walker, Tony R

2017-05-15

Marine plastic pollution has been a growing concern for decades. Single-use plastics (plastic bags and microbeads) are a significant source of this pollution. Although research outlining environmental, social, and economic impacts of marine plastic pollution is growing, few studies have examined policy and legislative tools to reduce plastic pollution, particularly single-use plastics (plastic bags and microbeads). This paper reviews current international market-based strategies and policies to reduce plastic bags and microbeads. While policies to reduce microbeads began in 2014, interventions for plastic bags began much earlier in 1991. However, few studies have documented or measured the effectiveness of these reduction strategies. Recommendations to further reduce single-use plastic marine pollution include: (i) research to evaluate effectiveness of bans and levies to ensure policies are having positive impacts on marine environments; and (ii) education and outreach to reduce consumption of plastic bags and microbeads at source. Copyright © 2017 Elsevier Ltd. All rights reserved.

CALCULATION OF DEFORMATION FORCE AT PLASTIC FORM-SHAPING OF FLANGE IN ROUND BILLET

Directory of Open Access Journals (Sweden)

L. A. Isaevich

2007-01-01

Full Text Available The paper introduces results concerning calculation of deformation force at plastic form-shaping of a flange in a round billet, having a preset extent of the transition zone from an internal pipe wall to a flange, that makes it possible to select a press of corresponding nominal force. 

Human Fertility Increases with the Marital-radius

DEFF Research Database (Denmark)

Labouriau, Rodrigo; Amorim, António

2008-01-01

We report a positive association between marital radius (distance between mates' birthplaces) and fertility detected in a large population. Spurious association due to socioeconomic factors is discarded by a conditional analysis involving income, education, and urbanicity. Strong evidence...

Correction of the exciton Bohr radius in monolayer transition metal dichalcogenides

Science.gov (United States)

Li, Run-Ze; Dong, Xi-Ying; Li, Zhi-Qing; Wang, Zi-Wu

2018-07-01

We theoretically investigate the correction of exciton Bohr radius in monolayer transition metal dichalcogenides (TMDCs) on different polar substrates arising from the exciton-optical phonon coupling, in which both the intrinsic longitudinal optical phonon and surface optical phonon modes couple with the exciton are taken into account. We find that the exciton Bohr radius is enlarged markedly due to these coupling. Moreover, it can be changed on a large scale by modulating the polarizability of polar substrate and the internal distance between the monolayer TMDCs and polar substrate. Theoretical result provides a potential explanation for the variation of the exciton Bohr radius in experimental measurement.

A feasible injection molding technique for the manufacturing of large diameter aspheric plastic lenses

Science.gov (United States)

Shieh, Jen-Yu; Wang, Luke K.; Ke, Shih-Ying

2010-07-01

A computer aided engineering (CAE) tool-assisted technique, using Moldex3D and aspheric analysis utility (AAU) software in a polycarbonate injection molding design, is proposed to manufacture large diameter aspheric plastic lenses. An experiment is conducted to verify the applicability/feasibility of the proposed technique. Using the preceding two software tools, these crucial process parameters associated with the surface profile errors and birefringence of a molded lens can be attainable. The strategy adopted here is to use the actual quantity of shrinkage after an injection molding trial of an aspherical plastic lens as a reference to perform the core shaping job while keeping the coefficients of aspheric surface, radius, and conic constant unchanged. The design philosophy is characterized by using the CAE tool as a guideline to pursue the best symmetry condition, followed by injection molding trials, to accelerate a product’s developmental time. The advantages are less design complexity and shorter developmental time for a product.

Nonlinear buckling analyses of a small-radius carbon nanotube

International Nuclear Information System (INIS)

Liu, Ning; Li, Min; Jia, Jiao; Wang, Yong-Gang

2014-01-01

Carbon nanotube (CNT) was first discovered by Sumio Iijima. It has aroused extensive attentions of scholars from all over the world. Over the past two decades, we have acquired a lot of methods to synthesize carbon nanotubes and learn their many incredible mechanical properties such as experimental methods, theoretical analyses, and computer simulations. However, the studies of experiments need lots of financial, material, and labor resources. The calculations will become difficult and time-consuming, and the calculations may be even beyond the realm of possibility when the scale of simulations is large, as for computer simulations. Therefore, it is necessary for us to explore a reasonable continuum model, which can be applied into nano-scale. This paper attempts to develop a mathematical model of a small-radius carbon nanotube based on continuum theory. An Isotropic circular cross-section, Timoshenko beam model is used as a simplified mechanical model for the small-radius carbon nanotube. Theoretical part is mainly based on modified couple stress theory to obtain the numerical solutions of buckling deformation. Meanwhile, the buckling behavior of the small radius carbon nanotube is simulated by Molecular Dynamics method. By comparing with the numerical results based on modified couple stress theory, the dependence of the small-radius carbon nanotube mechanical behaviors on its elasticity constants, small-size effect, geometric nonlinearity, and shear effect is further studied, and an estimation of the small-scale parameter of a CNT (5, 5) is obtained

Nonlinear buckling analyses of a small-radius carbon nanotube

Energy Technology Data Exchange (ETDEWEB)

Liu, Ning, E-mail: liuxiao@ase.buaa.edu.cn; Li, Min; Jia, Jiao [School of Aeronautic Science and Engineering, Beihang University, Beijing 100091 (China); Wang, Yong-Gang [Department of Applied Mechanics, China Agricultural University, Beijing 100083 (China)

2014-04-21

Carbon nanotube (CNT) was first discovered by Sumio Iijima. It has aroused extensive attentions of scholars from all over the world. Over the past two decades, we have acquired a lot of methods to synthesize carbon nanotubes and learn their many incredible mechanical properties such as experimental methods, theoretical analyses, and computer simulations. However, the studies of experiments need lots of financial, material, and labor resources. The calculations will become difficult and time-consuming, and the calculations may be even beyond the realm of possibility when the scale of simulations is large, as for computer simulations. Therefore, it is necessary for us to explore a reasonable continuum model, which can be applied into nano-scale. This paper attempts to develop a mathematical model of a small-radius carbon nanotube based on continuum theory. An Isotropic circular cross-section, Timoshenko beam model is used as a simplified mechanical model for the small-radius carbon nanotube. Theoretical part is mainly based on modified couple stress theory to obtain the numerical solutions of buckling deformation. Meanwhile, the buckling behavior of the small radius carbon nanotube is simulated by Molecular Dynamics method. By comparing with the numerical results based on modified couple stress theory, the dependence of the small-radius carbon nanotube mechanical behaviors on its elasticity constants, small-size effect, geometric nonlinearity, and shear effect is further studied, and an estimation of the small-scale parameter of a CNT (5, 5) is obtained.

CT virtual reality in the preoperative workup of malunited distal radius fractures: preliminary results

International Nuclear Information System (INIS)

Rieger, Michael; Gruber, Hannes; Jaschke, Werner R.; Gabl, Markus; Mallouhi, Ammar

2005-01-01

Our objective was to evaluate the usefulness of CT virtual preoperative planning in the surgical repositioning of malunited distal radius fracture. Eleven patients with malunited distal radius fracture underwent multislice CT of both wrists. A preoperative workup was performed in a virtual reality environment created from the CT data sets. Virtual planning comprised three main procedures, carrying out the virtual osteotomy of the radius, prediction of the final position of the distal radius after osteotomy and computer-assisted manufacturing of a repositioning device, which was later placed at the surgical osteotomy site to reposition objectively the distal radius fragment before fixation with the osteosynthesis. All patients tolerated the surgical procedure well. During surgery, the orthopedic surgeons were not required in any of the cases to alter the position of the distal radius that was determined by the repositioning device. At postoperative follow-up, the anatomic relationship of the distal radius was restored (radial inclination, 21.4 ; volar tilt, 10.3 ; ulnar variance, 0.5 mm). Clinically, a significant improvement of pronation (P=0.012), supination (P=0.01), flexion (P=0.001) and extension (P=0.006) was achieved. Pain decreased from 54 to 7 points. CT virtual reality is a valuable adjunct for the preoperative workup and surgical reposition of malunited distal radius fractures. (orig.)

The Numerical Simulation of the Crack Elastoplastic Extension Based on the Extended Finite Element Method

Directory of Open Access Journals (Sweden)

Xia Xiaozhou

2013-01-01

Full Text Available In the frame of the extended finite element method, the exponent disconnected function is introduced to reflect the discontinuous characteristic of crack and the crack tip enrichment function which is made of triangular basis function, and the linear polar radius function is adopted to describe the displacement field distribution of elastoplastic crack tip. Where, the linear polar radius function form is chosen to decrease the singularity characteristic induced by the plastic yield zone of crack tip, and the triangle basis function form is adopted to describe the displacement distribution character with the polar angle of crack tip. Based on the displacement model containing the above enrichment displacement function, the increment iterative form of elastoplastic extended finite element method is deduced by virtual work principle. For nonuniform hardening material such as concrete, in order to avoid the nonsymmetry characteristic of stiffness matrix induced by the non-associate flowing of plastic strain, the plastic flowing rule containing cross item based on the least energy dissipation principle is adopted. Finally, some numerical examples show that the elastoplastic X-FEM constructed in this paper is of validity.

Nuclear charge radius of 11Li

International Nuclear Information System (INIS)

Sanchez, Rodolfo; Noertershaeuser, Wilfried; Dax, Andreas; Ewald, Guido; Goette, Stefan; Kirchner, Reinhard; Kluge, H.-Juergen; Kuehl, Thomas; Wojtaszek, Agnieszka; Bushaw, Bruce A.; Drake, Gordon W. F.; Yan Zongchao; Zimmermann, Claus; Albers, Daniel; Behr, John; Bricault, Pierre; Dilling, Jens; Dombsky, Marik; Lassen, Jens; Phil Levy, C. D.

2006-01-01

We have determined the nuclear charge radius of 11 Li by high-precision laser spectroscopy. The experiment was performed at the TRIUMF-ISAC facility where the 7 Li- 11 Li isotope shift (IS) was measured in the 2s → 3s electronic transition using Doppler-free two-photon spectroscopy with a relative accuracy better than 10 -5 . The accuracy for the IS of the other lithium isotopes was also improved. IS's are mainly caused by differences in nuclear mass, but changes in proton distribution also give small contributions. Comparing experimentally measured IS with advanced atomic calculation of purely mass-based shifts, including QED and relativistic effects, allows derivation of the nuclear charge radii. The radii are found to decrease monotonically from 6 Li to 9 Li, and then increase with 11 Li about 11% larger than 9 Li. These results are a benchmark for the open question as to whether nuclear core excitation by halo neutrons is necessary to explain the large nuclear matter radius of 11 Li; thus, the results are compared with a number of nuclear structure models.

Finite-Larmor-radius effects on z-pinch stability

Science.gov (United States)

Scheffel, Jan; Faghihi, Mostafa

1989-06-01

The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. We use the incompressible FLR MHD model; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2r dp/dr + m2B2/μ0 ≥ 0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the FLR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but not absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the crosssection for wavelengths λ/a ≤ 1, where a denotes the pinch radius. As a general z-pinch result a critical line-density limit Nmax = 5 × 1018 m-1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 1020 m-1.

Finite-Larmor-radius effects on z-pinch stability

Energy Technology Data Exchange (ETDEWEB)

Scheffel, J.; Faghihi, M. (Royal Inst. of Tech., Stockholm (Sweden))

1989-06-01

The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. The incompressible FLR MHD model is used; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2rdp/dr+m{sup 2}B{sup 2}/{mu}{sub 0}{ge}0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the LFR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but no absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the cross-section for wavelengths {lambda}/{alpha}{le}1, where {alpha} denotes the pinch radius. As a general z-pinch result a critical line-density limit ''N''{sub max}=5x10{sup 18}m{sup -1} is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 10{sup 20} m{sup -1}. (author).

Finite-Larmor-radius effects on z-pinch stability

International Nuclear Information System (INIS)

Scheffel, J.; Faghihi, M.

1989-01-01

The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. The incompressible FLR MHD model is used; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2rdp/dr+m 2 B 2 /μ 0 ≥0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the LFR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but no absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the cross-section for wavelengths λ/α≤1, where α denotes the pinch radius. As a general z-pinch result a critical line-density limit ''N'' max =5x10 18 m -1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 10 20 m -1 . (author)

33 CFR 165.168 - Safety Zones; Coast Guard Captain of the Port New York Fireworks Displays.

Science.gov (United States)

2010-07-01

... of the Port New York Fireworks Displays. 165.168 Section 165.168 Navigation and Navigable Waters... Guard District § 165.168 Safety Zones; Coast Guard Captain of the Port New York Fireworks Displays. (a... Upper New York Bay within a 360-yard radius of the fireworks barge in approximate position 40°41′16.5″ N...

A viscoplastic shear-zone model for episodic slow slip events in oceanic subduction zones

Science.gov (United States)

Yin, A.; Meng, L.

2016-12-01

Episodic slow slip events occur widely along oceanic subduction zones at the brittle-ductile transition depths ( 20-50 km). Although efforts have been devoted to unravel their mechanical origins, it remains unclear about the physical controls on the wide range of their recurrence intervals and slip durations. In this study we present a simple mechanical model that attempts to account for the observed temporal evolution of slow slip events. In our model we assume that slow slip events occur in a viscoplastic shear zone (i.e., Bingham material), which has an upper static and a lower dynamic plastic yield strength. We further assume that the hanging wall deformation is approximated as an elastic spring. We envision the shear zone to be initially locked during forward/landward motion but is subsequently unlocked when the elastic and gravity-induced stress exceeds the static yield strength of the shear zone. This leads to backward/trenchward motion damped by viscous shear-zone deformation. As the elastic spring progressively loosens, the hanging wall velocity evolves with time and the viscous shear stress eventually reaches the dynamic yield strength. This is followed by the termination of the trenchward motion when the elastic stress is balanced by the dynamic yield strength of the shear zone and the gravity. In order to account for the zig-saw slip-history pattern of typical repeated slow slip events, we assume that the shear zone progressively strengthens after each slow slip cycle, possibly caused by dilatancy as commonly assumed or by progressive fault healing through solution-transport mechanisms. We quantify our conceptual model by obtaining simple analytical solutions. Our model results suggest that the duration of the landward motion increases with the down-dip length and the static yield strength of the shear zone, but decreases with the ambient loading velocity and the elastic modulus of the hanging wall. The duration of the backward/trenchward motion depends

Influences on the radius of the auroral oval

Directory of Open Access Journals (Sweden)

S. E. Milan

2009-07-01

Full Text Available We examine the variation in the radius of the auroral oval, as measured from auroral images gathered by the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE spacecraft, in response to solar wind inputs measured by the Advanced Composition Explorer (ACE spacecraft for the two year interval June 2000 to May 2002. Our main finding is that the oval radius increases when the ring current, as measured by the Sym-H index, is intensified during geomagnetic storms. We discuss our findings within the context of the expanding/contracting polar cap paradigm, in terms of a modification of substorm onset conditions by the magnetic perturbation associated with the ring current.

Influence of asymmetrical drawing radius deviation in micro deep drawing

Science.gov (United States)

Heinrich, L.; Kobayashi, H.; Shimizu, T.; Yang, M.; Vollertsen, F.

2017-09-01

Nowadays, an increasing demand for small metal parts in electronic and automotive industries can be observed. Deep drawing is a well-suited technology for the production of such parts due to its excellent qualities for mass production. However, the downscaling of the forming process leads to new challenges in tooling and process design, such as high relative deviation of tool geometry or blank displacement compared to the macro scale. FEM simulation has been a widely-used tool to investigate the influence of symmetrical process deviations as for instance a global variance of the drawing radius. This study shows a different approach that allows to determine the impact of asymmetrical process deviations on micro deep drawing. In this particular case the impact of an asymmetrical drawing radius deviation and blank displacement on cup geometry deviation was investigated for different drawing ratios by experiments and FEM simulation. It was found that both variations result in an increasing cup height deviation. Nevertheless, with increasing drawing ratio a constant drawing radius deviation has an increasing impact, while blank displacement results in a decreasing offset of the cups geometry. This is explained by different mechanisms that result in an uneven cup geometry. While blank displacement leads to material surplus on one side of the cup, an unsymmetrical radius deviation on the other hand generates uneven stretching of the cups wall. This is intensified for higher drawing ratios. It can be concluded that the effect of uneven radius geometry proves to be of major importance for the production of accurately shaped micro cups and cannot be compensated by intentional blank displacement.

Testing the white dwarf mass-radius relationship with eclipsing binaries

Science.gov (United States)

Parsons, S. G.; Gänsicke, B. T.; Marsh, T. R.; Ashley, R. P.; Bours, M. C. P.; Breedt, E.; Burleigh, M. R.; Copperwheat, C. M.; Dhillon, V. S.; Green, M.; Hardy, L. K.; Hermes, J. J.; Irawati, P.; Kerry, P.; Littlefair, S. P.; McAllister, M. J.; Rattanasoon, S.; Rebassa-Mansergas, A.; Sahman, D. I.; Schreiber, M. R.

2017-10-01

We present high-precision, model-independent, mass and radius measurements for 16 white dwarfs in detached eclipsing binaries and combine these with previously published data to test the theoretical white dwarf mass-radius relationship. We reach a mean precision of 2.4 per cent in mass and 2.7 per cent in radius, with our best measurements reaching a precision of 0.3 per cent in mass and 0.5 per cent in radius. We find excellent agreement between the measured and predicted radii across a wide range of masses and temperatures. We also find the radii of all white dwarfs with masses less than 0.48 M⊙ to be fully consistent with helium core models, but they are on average 9 per cent larger than those of carbon-oxygen core models. In contrast, white dwarfs with masses larger than 0.52 M⊙ all have radii consistent with carbon-oxygen core models. Moreover, we find that all but one of the white dwarfs in our sample have radii consistent with possessing thick surface hydrogen envelopes (10-5 ≥ MH/MWD ≥ 10-4), implying that the surface hydrogen layers of these white dwarfs are not obviously affected by common envelope evolution.

Molecular-dynamics Simulation-based Cohesive Zone Representation of Intergranular Fracture Processes in Aluminum

Science.gov (United States)

Yamakov, Vesselin I.; Saether, Erik; Phillips, Dawn R.; Glaessgen, Edward H.

2006-01-01

A traction-displacement relationship that may be embedded into a cohesive zone model for microscale problems of intergranular fracture is extracted from atomistic molecular-dynamics simulations. A molecular-dynamics model for crack propagation under steady-state conditions is developed to analyze intergranular fracture along a flat 99 [1 1 0] symmetric tilt grain boundary in aluminum. Under hydrostatic tensile load, the simulation reveals asymmetric crack propagation in the two opposite directions along the grain boundary. In one direction, the crack propagates in a brittle manner by cleavage with very little or no dislocation emission, and in the other direction, the propagation is ductile through the mechanism of deformation twinning. This behavior is consistent with the Rice criterion for cleavage vs. dislocation blunting transition at the crack tip. The preference for twinning to dislocation slip is in agreement with the predictions of the Tadmor and Hai criterion. A comparison with finite element calculations shows that while the stress field around the brittle crack tip follows the expected elastic solution for the given boundary conditions of the model, the stress field around the twinning crack tip has a strong plastic contribution. Through the definition of a Cohesive-Zone-Volume-Element an atomistic analog to a continuum cohesive zone model element - the results from the molecular-dynamics simulation are recast to obtain an average continuum traction-displacement relationship to represent cohesive zone interaction along a characteristic length of the grain boundary interface for the cases of ductile and brittle decohesion. Keywords: Crack-tip plasticity; Cohesive zone model; Grain boundary decohesion; Intergranular fracture; Molecular-dynamics simulation

Neutron charge radius and the neutron electric form factor

International Nuclear Information System (INIS)

Gentile, T. R.; Crawford, C. B.

2011-01-01

For nearly forty years, the Galster parametrization has been employed to fit existing data for the neutron electric form factor, G E n , vs the square of the four-momentum transfer, Q 2 . Typically this parametrization is constrained to be consistent with experimental data for the neutron charge radius. However, we find that the Galster form does not have sufficient freedom to accommodate reasonable values of the radius without constraining or compromising the fit. In addition, the G E n data are now at sufficient precision to motivate a two-parameter fit (or three parameters if we include thermal neutron data). Here we present a modified form of a two-dipole parametrization that allows this freedom and fits both G E n (including recent data at both low and high four-momentum transfer) and the charge radius well with simple, well-defined parameters. Analysis reveals that the Galster form is essentially a two-parameter approximation to the two-dipole form but becomes degenerate if we try to extend it naturally to three parameters.

[Matrimonial radius and anthropologic differentiation of the population of the Peloponnese, Greece].

Science.gov (United States)

Pitsios, T K

1983-09-01

Mean matrimonial radius (MMR) and mean breeding radius (MBR) were studied in the population of the Peloponnese (Greece). The historical and geographical causes of these important genetical variables are discussed considering, too, their effects on the anthropological differentiation of this population.

A cohesive zone framework for environmentally assisted fatigue

DEFF Research Database (Denmark)

del Busto, Susana; Betegón, Covadonga; Martínez Pañeda, Emilio

2017-01-01

We present a compelling finite element framework to model hydrogen assisted fatigue by means of a hydrogen- and cycle-dependent cohesive zone formulation. The model builds upon: (i) appropriate environmental boundary conditions, (ii) a coupled mechanical and hydrogen diffusion response, driven...... by chemical potential gradients, (iii) a mechanical behavior characterized by finite deformation J2 plasticity, (iv) a phenomenological trapping model, (v) an irreversible cohesive zone formulation for fatigue, grounded on continuum damage mechanics, and (vi) a traction-separation law dependent on hydrogen...... coverage calculated from first principles. The computations show that the present scheme appropriately captures the main experimental trends; namely, the sensitivity of fatigue crack growth rates to the loading frequency and the environment. The role of yield strength, work hardening, and constraint...

Plastic deformation and failure mechanisms in nano-scale notched metallic glass specimens under tensile loading

Science.gov (United States)

Dutta, Tanmay; Chauniyal, Ashish; Singh, I.; Narasimhan, R.; Thamburaja, P.; Ramamurty, U.

2018-02-01

In this work, numerical simulations using molecular dynamics and non-local plasticity based finite element analysis are carried out on tensile loading of nano-scale double edge notched metallic glass specimens. The effect of acuteness of notches as well as the metallic glass chemical composition or internal material length scale on the plastic deformation response of the specimens are studied. Both MD and FE simulations, in spite of the fundamental differences in their nature, indicate near-identical deformation features. Results show two distinct transitions in the notch tip deformation behavior as the acuity is increased, first from single shear band dominant plastic flow localization to ligament necking, and then to double shear banding in notches that are very sharp. Specimens with moderately blunt notches and composition showing wider shear bands or higher material length scale characterizing the interaction stress associated with flow defects display profuse plastic deformation and failure by ligament necking. These results are rationalized from the role of the interaction stress and development of the notch root plastic zones.

ASTROPHYSICAL PARAMETERS AND HABITABLE ZONE OF THE EXOPLANET HOSTING STAR GJ 581

International Nuclear Information System (INIS)

Von Braun, Kaspar; Kane, Stephen R.; Ciardi, David R.; Boyajian, Tabetha S.; McAlister, Harold A.; Henry, Todd J.; Jao, Wei-Chun; Riedel, Adric R.; Van Belle, Gerard T.; Lopez-Morales, Mercedes; Subasavage, John P.; Schaefer, Gail; Ten Brummelaar, Theo A.; Sturmann, Laszlo; Sturmann, Judit; Mazingue, Jude; Turner, Nils H.; Farrington, Chris; Goldfinger, P. J.; Ridgway, Stephen

2011-01-01

GJ 581 is an M dwarf host of a multiplanet system. We use long-baseline interferometric measurements from the CHARA Array, coupled with trigonometric parallax information, to directly determine its physical radius to be 0.299 ± 0.010 R sun . Literature photometry data are used to perform spectral energy distribution fitting in order to determine GJ 581's effective surface temperature T EFF = 3498 ± 56 K and its luminosity L = 0.01205 ± 0.00024 L sun . From these measurements, we recompute the location and extent of the system's habitable zone and conclude that two of the planets orbiting GJ 581, planets d and g, spend all or part of their orbit within or just on the edge of the habitable zone.

A unified model of hydride cracking based on elasto-plastic energy release rate over a finite crack extension

International Nuclear Information System (INIS)

Zheng, X.J.; Metzger, D.R.; Sauve, R.G.

1995-01-01

A fracture criterion based on energy balance is proposed for elasto-plastic cracking at hydrides in zirconium, assuming a finite length of crack advance. The proposed elasto-plastic energy release rate is applied to the crack initiation at hydrides in smooth and notched surfaces, as well as the subsequent delayed hydride cracking (DHC) considering limited crack-tip plasticity. For a smooth or notched surface of an elastic body, the fracture parameter is related to the stress intensity factor for the initiated crack. For DHC, a unique curve relates the non-dimensionalized elasto-plastic energy release rate with the length of crack extension relative to the plastic zone size. This fracture criterion explains experimental observations concerning DHC in a qualitative manner. Quantitative comparison with experiments is made for fracture toughness and DHC tests on specimens containing certain hydride structures; very good agreement is obtained. ((orig.))

The estimated evacuation time for the emergency planning zone of the Kori nuclear site, with a focus on the precautionary action zone

Energy Technology Data Exchange (ETDEWEB)

Lee, Jang Hee; Jeong, Jae Jun [School of Mechanical Engineering, Pusan National University, Busan (Korea, Republic of); Shin, Won Ki; Song, Eun Young; Cho, Cheol Woo [Div. of Nuclear Safety, Busan Metropolitan City, Busan (Korea, Republic of)

2016-09-15

The emergency planning zone (EPZ) of the city of Busan is divided into the precautionary actions zone (PAZ) and the urgent protective action planning zone; which have a 5-km radius and a 20-km to 21-km radius from the nuclear power plant site, respectively. In this study, we assumed that a severe accident occurred at Shin-Kori nuclear unit 3 and evaluated the dispersion speed of radiological material at each distance at various wind speeds, and estimated the effective dose equivalent and the evacuation time of PAZ residents with the goal of supporting off-site emergency action planning for the nuclear site. The total effective dose equivalent, which shows the effect of released radioactive materials on the residents, was evaluated using the RASCAL 4.2 program. In addition, a survey of 1,036 residents was performed using a standardized questionnaire, and the resident evacuation time according to road and distance was analyzed using the VISSIM 6.0 program. According to the results obtained using the VISSIM and RASCAL programs, it would take approximately 80 to 252.2 minutes for permanent residents to move out of the PAZ boundary, 40 to 197.2 minutes for students, 60 to 232.2 minutes for the infirm, such as elderly people and those in a nursing home or hospital, and 30 to 182.2 minutes for those temporarily within the area. Consequently, in the event of any delay in the evacuation, it is estimated that the residents would be exposed to up to 10 mSv·h-1 of radiation at the Exclusion Area Boundaries (EAB) boundary and 4-6 mSv·h-1 at the PAZ boundary. It was shown that the evacuation time for the residents is adequate in light of the time lapse from the initial moment of a severe accident to the radiation release. However, in order to minimize the evacuation time, it is necessary to maintain a system of close collaboration to avoid traffic congestion and spontaneous evacuation attempts.

The estimated evacuation time for the emergency planning zone of the Kori nuclear site, with a focus on the precautionary action zone

International Nuclear Information System (INIS)

Lee, Jang Hee; Jeong, Jae Jun; Shin, Won Ki; Song, Eun Young; Cho, Cheol Woo

2016-01-01

The emergency planning zone (EPZ) of the city of Busan is divided into the precautionary actions zone (PAZ) and the urgent protective action planning zone; which have a 5-km radius and a 20-km to 21-km radius from the nuclear power plant site, respectively. In this study, we assumed that a severe accident occurred at Shin-Kori nuclear unit 3 and evaluated the dispersion speed of radiological material at each distance at various wind speeds, and estimated the effective dose equivalent and the evacuation time of PAZ residents with the goal of supporting off-site emergency action planning for the nuclear site. The total effective dose equivalent, which shows the effect of released radioactive materials on the residents, was evaluated using the RASCAL 4.2 program. In addition, a survey of 1,036 residents was performed using a standardized questionnaire, and the resident evacuation time according to road and distance was analyzed using the VISSIM 6.0 program. According to the results obtained using the VISSIM and RASCAL programs, it would take approximately 80 to 252.2 minutes for permanent residents to move out of the PAZ boundary, 40 to 197.2 minutes for students, 60 to 232.2 minutes for the infirm, such as elderly people and those in a nursing home or hospital, and 30 to 182.2 minutes for those temporarily within the area. Consequently, in the event of any delay in the evacuation, it is estimated that the residents would be exposed to up to 10 mSv·h-1 of radiation at the Exclusion Area Boundaries (EAB) boundary and 4-6 mSv·h-1 at the PAZ boundary. It was shown that the evacuation time for the residents is adequate in light of the time lapse from the initial moment of a severe accident to the radiation release. However, in order to minimize the evacuation time, it is necessary to maintain a system of close collaboration to avoid traffic congestion and spontaneous evacuation attempts

X-ray Spectroscopy of the Virgo Cluster out to the Virial Radius

OpenAIRE

Urban, O.; Werner, N.; Simionescu, A.; Allen, S. W.; Böhringer, H.

2011-01-01

We present results from the analysis of a mosaic of thirteen XMM-Newton pointings covering the Virgo Cluster from its center northwards out to a radius r~1.2 Mpc (~4.5 degrees), reaching the virial radius and beyond. This is the first time that the properties of a modestly sized (M_vir~1.4e14 M_sun, kT~2.3 keV), dynamically young cluster have been studied out to the virial radius. The density profile of the cluster can be described by a surprisingly shallow power-law with index 1.21+/-0.12. I...

Methodology for plastic fracture. A progress report

International Nuclear Information System (INIS)

Wilkinson, J.P.D.; Hahn, G.T.; Smith, R.E.E.

1977-01-01

The initiation and growth of flaws in pressure vessels under overload conditions is distinguished by a number of unique features, such as large scale yielding, three-dimensional structural and flaw configurations, and failure instabilities that may be controlled by either toughness or plastic flow. In order to develop a broadly applicable methodology of plastic fracture, these features require the following analytical and experimental studies: development of criteria for crack initiation and growth under large scale yielding; the use of the finite element method to describe elastic-plastic behavior of both the structure and the crack tip region; and extensive experimental studies on laboratory scale and large scale specimens, which attempt to reproduce the pertinent plastic flow and crack growth phenomena. A variety of candidate criteria for crack initiation and growth are examined. For the case of crack initiation, these criteria include the J-integral, crack opening displacement, and strain amplitude. In the case of crack growth, the criteria examined include in addition the strain amplitude at the crack tip, work done in a crack tip process zone, and a generalized energy release-rate approach. Each test specimen configuration is analyzed through the finite element method in order to predict its experimental behavior. Specimens include the compact tension specimen and center cracked panels. The basic materials used in the program are a single heat of reactor grade A533 Grade B Class 1 steel, purchased in the form of a plate of size 4.5 m (178 in.) square and 0.2 m (8 in.) thick, and two alloys with yield strength-to-roughness ratios about five times

Small-scale dislocation plasticity in strontium titanate

Energy Technology Data Exchange (ETDEWEB)

Stukowski, Alexander; Javaid, Farhan; Durst, Karsten; Albe, Karsten [Technische Universitaet Darmstadt (Germany)

2016-07-01

Strontium titanate (STO) is an optically transparent perovskite oxide ceramic material. In contrast to other ceramics, single crystal STO plastically deforms under ambient condition, without showing a phase transition or early fracture. This remarkable ductility makes it a prime candidate for different technological applications. However, while the mechanical behavior of bulk STO has been studied extensively using uniaxial compression testing techniques, little is known about the local, small-scale behavior and the details of dislocation-based nanoplasticity in this perovskite material. In this contribution we compare results obtained from new nanoindentation experiments and corresponding large-scale molecular dynamics simulations. The evolution of the plastic zone and dislocation structures that form underneath the indenter is investigated using etch-pit methods in experiments and a novel three-dimensional defect identification technique in atomistic computer models. The latter allows tracing the evolution of the complete dislocation line network as function of indentation depth, quantifying the activity of different slip systems, and correlating this information with the recorded load-displacement curves and hardness data.

Possibility to determine the radius of accretion disk by gravitational waves

International Nuclear Information System (INIS)

Sotani, H; Saijo, M

2007-01-01

We investigate gravitational waves from a dust disk around a Schwarzschild black hole to focus on whether we can extract any of its physical properties from a direct detection of gravitational waves. We adopt a black hole perturbation approach in a time domain, which is a satisfactory approximation to illustrate a dust disk in a supermassive black hole. We find that we can determine the radius of the disk by using the power spectrum of gravitational waves and that our method to extract the radius works for a disk of arbitrary density distribution. Therefore we believe a possibility exists for determining the radius of the disk from a direct observation of gravitational waves detected by the Laser Interferometer Space Antenna

Emergent spatial patterns of excitatory and inhibitory synaptic strengths drive somatotopic representational discontinuities and their plasticity in a computational model of primary sensory cortical area 3b

Directory of Open Access Journals (Sweden)

Kamil A. Grajski

2016-07-01

Full Text Available Mechanisms underlying the emergence and plasticity of representational discontinuities in the mammalian primary somatosensory cortical representation of the hand are investigated in a computational model. The model consists of an input lattice organized as a three-digit hand forward-connected to a lattice of cortical columns each of which contains a paired excitatory and inhibitory cell. Excitatory and inhibitory synaptic plasticity of feedforward and lateral connection weights is implemented as a simple covariance rule and competitive normalization. Receptive field properties are computed independently for excitatory and inhibitory cells and compared within and across columns. Within digit representational zones intracolumnar excitatory and inhibitory receptive field extents are concentric, single-digit, small, and unimodal. Exclusively in representational boundary-adjacent zones, intracolumnar excitatory and inhibitory receptive field properties diverge: excitatory cell receptive fields are single-digit, small, and unimodal; and the paired inhibitory cell receptive fields are bimodal, double-digit, and large. In simulated syndactyly (webbed fingers, boundary-adjacent intracolumnar receptive field properties reorganize to within-representation type; divergent properties are reacquired following syndactyly release. This study generates testable hypotheses for assessment of cortical laminar-dependent receptive field properties and plasticity within and between cortical representational zones. For computational studies, present results suggest that concurrent excitatory and inhibitory plasticity may underlie novel emergent properties.

On the charge radius of the neutrino

CERN Document Server

Bernabeu, J; Papavassiliou, J; Vidal, J

2000-01-01

Using the pinch technique we construct at one-loop order a neutrino charge radius, which is finite, depends neither on the gauge-fixing parameter nor on the gauge-fixing scheme employed, and is process-independent. This definition stems solely from an effective proper photon-neutrino one-loop vertex, with no reference to box or self-energy contributions. The role of the $WW$ box in this construction is critically examined. In particular it is shown that the exclusion of the effective WW box from the definition of the neutrino charge radius is not a matter of convention but is in fact dynamically realized when the target-fermions are right-handedly polarized. In this way we obtain a unique decomposition of effective self-energies, vertices, and boxes, which separately respect electroweak gauge invariance. We elaborate on the tree-level origin of the mechanism which enforces at one-loop level massive cancellations among the longitudinal momenta appearing in the Feynman diagrams, and in particular those associat...

Constraining the mass and radius of neutron stars in globular clusters

Science.gov (United States)

Steiner, A. W.; Heinke, C. O.; Bogdanov, S.; Li, C. K.; Ho, W. C. G.; Bahramian, A.; Han, S.

2018-05-01

We analyse observations of eight quiescent low-mass X-ray binaries in globular clusters and combine them to determine the neutron star mass-radius curve and the equation of state of dense matter. We determine the effect that several uncertainties may have on our results, including uncertainties in the distance, the atmosphere composition, the neutron star maximum mass, the neutron star mass distribution, the possible presence of a hotspot on the neutron star surface, and the prior choice for the equation of state of dense matter. The distance uncertainty is implemented in a new Gaussian blurring method that can be directly applied to the probability distribution over mass and radius. We find that the radius of a 1.4 solar mass neutron star is most likely from 10 to 14 km and that tighter constraints are only possible with stronger assumptions about the nature of the neutron stars, the systematics of the observations, or the nature of dense matter. Strong phase transitions in the equation of state are preferred, and in this case, the radius is likely smaller than 12 km. However, radii larger than 12 km are preferred if the neutron stars have uneven temperature distributions.

MRI of fractures of the distal radius: comparison with conventional radiographs

International Nuclear Information System (INIS)

Spence, L.D.; Eustace, S.

1998-01-01

Objective. To compare the evaluation of fractures of the distal radius with MRI and conventional radiographs. To demonstrate the ability of MRI to detect unsuspected soft tissue derangement accompanying this common injury. Design and patients. Twenty-one consecutive inpatients admitted following fracture of the distal radius underwent preoperative evaluation with both conventional radiographs and MRI. In each case, analysis was made of both the osseous and soft tissue injury. MRI findings were compared with those identified on conventional radiographs and at subsequent surgical fixation. Results. Of 21 patients with fractures of the distal radius, 20 had extension to the radiocarpal articulation, 14 had distal radio-ulnar joint extension and 5 had avulsion of the ulnar styloid.Occult carpal bone fractures accompanying fracture of the distal radius were identified in two patients: one of the capitate and the other of the second metacarpal base. Ten patients (48%) had associated soft tissue injury: six patients had scapholunate ligament rupture, two patients had disruption of the triangular fibrocartilage, one patient had extensor carpi ulnaris tenosynovitis and one patient had a tear of a dorsal radiocarpal ligament. Of five patients with ulnar styloid avulsions, none had evidence of triangular fibrocartilage tears. Conclusion. MRI affords better evaluation of osseous injury accompanying distal radial fractures than conventional radiographs. Intra-articular soft tissue injury accompanies distal radial fractures in almost 50% of cases. Scapholunate ligament disruption commonly accompanies intra-articular fracture through the lunate facet of the distal radius. Fracture of the ulnar styloid is infrequently associated with tear of the triangular fibrocartilage. (orig.)

MRI of fractures of the distal radius: comparison with conventional radiographs

Energy Technology Data Exchange (ETDEWEB)

Spence, L.D.; Eustace, S. [Medical Center, Boston, MA (United States). Dept. of Radiol.; Savenor, A.; Nwachuku, I.; Tilsley, J. [Department of Orthopedics, Boston Medical Center, Boston, MA 02118 (United States)

1998-05-01

Objective. To compare the evaluation of fractures of the distal radius with MRI and conventional radiographs. To demonstrate the ability of MRI to detect unsuspected soft tissue derangement accompanying this common injury. Design and patients. Twenty-one consecutive inpatients admitted following fracture of the distal radius underwent preoperative evaluation with both conventional radiographs and MRI. In each case, analysis was made of both the osseous and soft tissue injury. MRI findings were compared with those identified on conventional radiographs and at subsequent surgical fixation. Results. Of 21 patients with fractures of the distal radius, 20 had extension to the radiocarpal articulation, 14 had distal radio-ulnar joint extension and 5 had avulsion of the ulnar styloid.Occult carpal bone fractures accompanying fracture of the distal radius were identified in two patients: one of the capitate and the other of the second metacarpal base. Ten patients (48%) had associated soft tissue injury: six patients had scapholunate ligament rupture, two patients had disruption of the triangular fibrocartilage, one patient had extensor carpi ulnaris tenosynovitis and one patient had a tear of a dorsal radiocarpal ligament. Of five patients with ulnar styloid avulsions, none had evidence of triangular fibrocartilage tears. Conclusion. MRI affords better evaluation of osseous injury accompanying distal radial fractures than conventional radiographs. Intra-articular soft tissue injury accompanies distal radial fractures in almost 50% of cases. Scapholunate ligament disruption commonly accompanies intra-articular fracture through the lunate facet of the distal radius. Fracture of the ulnar styloid is infrequently associated with tear of the triangular fibrocartilage. (orig.) With 5 figs., 16 refs.

Mixed-mode elastic-plastic fracture of 2024-T351 aluminium alloy

International Nuclear Information System (INIS)

Sakata, Masaru; Aoki, Shigeru; Kishimoto, Kikuo; Chikugo, Hiroshi; Takizawa, Masakazu.

1985-01-01

In order to evaluate accurately the strength and structural soundness of the structures made of high toughness materials, it is necessary to clarify the fracture behavior under the loading condition of mixed mode such as oblique cracks as well as the elasto-plastic fracture behavior of the materials in the case of single opening displacement type mode. About the fracture condition in the state of mixed mode, various theories based on the linear fracture mechanics have been proposed. In this study, the elasto-plastic fracture toughness test of mixed mode was carried out by using an aluminum alloy as the subject, and the behavior of dulling and development of cracks was observed with a scanning electron microscope. Moreover, the state of deformation of the test pieces was analyzed by elasto-plastic finite element method, thus the parameters controlling the elasto-plastic fracture of mixed mode were examined. In the range of this study, the limiting stretch zone width in the case of loading of mixed mode was 12 μm similarly to the case of single mode. Also in the case of mixed mode, there was distinct difference between the inclination of a dulling straight line and an R-curve, and the limit value of J intergral was determined by their intersection. (Kako, I.)

Atomic radii for atoms with the 6s shell outermost: The effective atomic radius and the van der Waals radius from 55Cs to 80Hg

Directory of Open Access Journals (Sweden)

Hiroshi Tatewaki

2015-06-01

Full Text Available We consider, for atoms from 55Cs to 80Hg, the effective atomic radius (rear, which is defined as the distance from the nucleus at which the magnitude of the electric field is equal to that in He at one half of the equilibrium bond length of He2. The values of rear are about 50% larger than the mean radius of the outermost occupied orbital of 6s, . The value of rear decreases from 55Cs to 56Ba and undergoes increases and decreases with rising nuclear charge from 57La to 70Y b. In fact rear is understood as comprising two interlaced sequences; one consists of 57La, 58Ce, and 64Gd, which have electronic configuration (4fn−1(5d1(6s2, and the remaining atoms have configuration (4fn(6s2. The sphere defined by rear contains 85%–90% of the 6s electrons. From 71Lu to 80Hg the radius rear also involves two sequences, corresponding to the two configurations 5dn+16s1 and 5dn6s2. The radius rear according to the present methodology is considerably larger than rvdW obtained by other investigators, some of who have found values of rvdW close to .

Experimental and numerical investigation of laser forming of cylindrical surfaces with arbitrary radius of curvature

Directory of Open Access Journals (Sweden)

Mehdi Safari

2016-09-01

Full Text Available In this work, laser forming of cylindrical surfaces with arbitrary radius of curvature is investigated experimentally and numerically. For laser forming of cylindrical surfaces with arbitrary radius of curvature, a new and comprehensive method is proposed in this paper. This method contains simple linear irradiating lines and using an analytical method, required process parameters for laser forming of a cylindrical surface with a specific radius of curvature is proposed. In this method, laser output power, laser scanning speed and laser beam diameter are selected based on laser machine and process limitations. As in the laser forming of a cylindrical surface, parallel irradiating lines are needed; therefore key parameter for production of a cylindrical surface with a specific radius of curvature is the number of irradiating lines. Hence, in the proposed analytical method, the required number of irradiating lines for production of a cylindrical surface with a specific radius of curvature is suggested. Performance of the proposed method for production of cylindrical surface with a specific radius of curvature is verified with experimental tests. The results show that using proposed analytical method, cylindrical surfaces with any radius of curvature can be produced successfully.

Reconstruction of lower end of radius using vascularized upper end of fibula

Directory of Open Access Journals (Sweden)

Koul Ashok

2007-01-01

Full Text Available Background: Giant cell tumor is a fairly common locally invasive tumor in young adults. The lower end of the radius is the second commonest site for this tumor. The most common treatment for this tumor is curettage with or without bone grafting but it carries a significant rate of recurrence. Excision is the treatment of choice, especially for cases in which the cortex has been breached. After excision of the distal end of the radius, different procedures have been described to reconstruct the defect of distal radius. These include partial arthrodesis and hemiarthroplasty using the upper end of the fibula. The upper end of the fibula has a morphological resemblance to the lower end of the radius and has been used to replace the latter. Traditionally it was used as a ′free′ (non-vascularized graft. More recently the upper end of the fibula has been transferred as a vascularized transfer for the same purpose. Though vascularized transfer should be expected to be more physiological, its superiority over the technically simpler non-vascularized transfer has not been conclusively proven. Materials and Methods: Two patients are presented who had giant cell tumor of distal radius. They underwent wide local excision and reconstruction with free vascularized upper end of the fibula. Result: Follow-up period was two and a half years and 12 months respectively. Both patients have returned to routine work. One patient has excellent functional result and the other has a good result. Conclusion: Vascularized upper end of fibula transfer is a reliable method of reconstruction for loss of the distal end of the radius that restores local anatomy and physiology.

Strain localisation in mechanically layered rocks beneath detachment zones: insights from numerical modelling

Directory of Open Access Journals (Sweden)

L. Le Pourhiet

2013-04-01

Full Text Available We have designed a series of fully dynamic numerical simulations aimed at assessing how the orientation of mechanical layering in rocks controls the orientation of shear bands and the depth of penetration of strain in the footwall of detachment zones. Two parametric studies are presented. In the first one, the influence of stratification orientation on the occurrence and mode of strain localisation is tested by varying initial dip of inherited layering in the footwall with regard to the orientation of simple shear applied at the rigid boundary simulating a rigid hanging wall, all scaling and rheological parameter kept constant. It appears that when Mohr–Coulomb plasticity is being used, shear bands are found to localise only when the layering is being stretched. This corresponds to early deformational stages for inital layering dipping in the same direction as the shear is applied, and to later stages for intial layering dipping towards the opposite direction of shear. In all the cases, localisation of the strain after only γ=1 requires plastic yielding to be activated in the strong layer. The second parametric study shows that results are length-scale independent and that orientation of shear bands is not sensitive to the viscosity contrast or the strain rate. However, decreasing or increasing strain rate is shown to reduce the capacity of the shear zone to localise strain. In the later case, the strain pattern resembles a mylonitic band but the rheology is shown to be effectively linear. Based on the results, a conceptual model for strain localisation under detachment faults is presented. In the early stages, strain localisation occurs at slow rates by viscous shear instabilities but as the layered media is exhumed, the temperature drops and the strong layers start yielding plastically, forming shear bands and localising strain at the top of the shear zone. Once strain localisation has occured, the deformation in the shear band becomes

Plastic Surgery

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Plastic Surgery KidsHealth / For Teens / Plastic Surgery What's in ... her forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word " ...

Elastic-Plastic Nonlinear Response of a Space Shuttle External Tank Stringer. Part 2; Thermal and Mechanical Loadings

Science.gov (United States)

Knight, Norman F., Jr.; Warren, Jerry E.; Elliott, Kenny B.; Song, Kyongchan; Raju, Ivatury S.

2012-01-01

Elastic-plastic, large-deflection nonlinear thermo-mechanical stress analyses are performed for the Space Shuttle external tank s intertank stringers. Detailed threedimensional finite element models are developed and used to investigate the stringer s elastic-plastic response for different thermal and mechanical loading events from assembly through flight. Assembly strains caused by initial installation on an intertank panel are accounted for in the analyses. Thermal loading due to tanking was determined to be the bounding loading event. The cryogenic shrinkage caused by tanking resulted in a rotation of the intertank chord flange towards the center of the intertank, which in turn loaded the intertank stringer feet. The analyses suggest that the strain levels near the first three fasteners remain sufficiently high that a failure may occur. The analyses also confirmed that the installation of radius blocks on the stringer feet ends results in an increase in the stringer capability.

Influence of plastic deformation on nitriding of a molybdenum-hafnium alloy

International Nuclear Information System (INIS)

Lakhtin, Yu.M.; Kogan, Ya.D.; Shashkov, D.P.; Likhacheva, T.E.

1982-01-01

The influence of a preliminary plastic strain on the structure and properties of molybdenum alloy with 0.2 wt.% Hf upon nitriding in the ammonia medium at 900-1200 deg C during 1-6 h is investigated. The study of microhardness distribution across the nitrided layer thickness has shown that with increase of the degree of preliminary plastic strain up to 50 % the nitrided layer hardness decreases and with further reduction growth up to 90 % - increases. Nitriding sharply (hundred times) increases wear resistance of molybdenum alloy with hafnium addition. At the reduction degree 25 % the wear resistance is less than at other values of percentage reduction in area owing to the minimum thickness of the nitride zone. The alloy strained before nitriding by 25 % has shown the best results during heat resistance testing

Plastic dosimeter

International Nuclear Information System (INIS)

Nagai, Shiro; Matsuda, Kohji.

1988-01-01

The report outlines major features and applications of plastic dosimeters. Some plastic dosimeters, including the CTA and PVC types, detect the response of the plastic material itself to radiations while others, such as pigment-added plastic dosimeters, contain additives as radiation detecting material. Most of these dosimeters make use of color centers produced in the dosimeter by radiations. The PMMA dosimeter is widely used in the field of radiation sterilization of food, feed and medical apparatus. The blue cellophane dosimeter is easy to handle if calibrated appropriately. The rad-color dosimeter serves to determine whether products have been irradiated appropriately. The CTA dosimeter has better damp proofing properties than the blue cellophane type. The pigment-added plastic dosimeter consists of a resin such as nylon, CTA or PVC that contains a dye. Some other plastic dosimeters are also described briefly. Though having many advantages, these plastic dosimeter have disadvantages as well. Some of their major disadvantages, including fading as well as large dependence on dose, temperature, humidity and anviroment, are discussed. (Nogami, K.)

Microbial colonization and degradation of polyethylene and biodegradable plastic bags in temperate fine-grained organic-rich marine sediments.

Science.gov (United States)

Nauendorf, Alice; Krause, Stefan; Bigalke, Nikolaus K; Gorb, Elena V; Gorb, Stanislav N; Haeckel, Matthias; Wahl, Martin; Treude, Tina

2016-02-15

To date, the longevity of plastic litter at the sea floor is poorly constrained. The present study compares colonization and biodegradation of plastic bags by aerobic and anaerobic benthic microbes in temperate fine-grained organic-rich marine sediments. Samples of polyethylene and biodegradable plastic carrier bags were incubated in natural oxic and anoxic sediments from Eckernförde Bay (Western Baltic Sea) for 98 days. Analyses included (1) microbial colonization rates on the bags, (2) examination of the surface structure, wettability, and chemistry, and (3) mass loss of the samples during incubation. On average, biodegradable plastic bags were colonized five times higher by aerobic and eight times higher by anaerobic microbes than polyethylene bags. Both types of bags showed no sign of biodegradation during this study. Therefore, marine sediment in temperate coastal zones may represent a long-term sink for plastic litter and also supposedly compostable material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coupled THM processes in EDZ of crystalline rocks using an elasto-plastic cellular automaton

Science.gov (United States)

Pan, Peng-Zhi; Feng, Xia-Ting; Huang, Xiao-Hua; Cui, Qiang; Zhou, Hui

2009-05-01

This paper aims at a numerical study of coupled thermal, hydrological and mechanical processes in the excavation disturbed zones (EDZ) around nuclear waste emplacement drifts in fractured crystalline rocks. The study was conducted for two model domains close to an emplacement tunnel; (1) a near-field domain and (2) a smaller wall-block domain. Goodman element and weak element were used to represent the fractures in the rock mass and the rock matrix was represented as elasto-visco-plastic material. Mohr-Coulomb criterion and a non-associated plastic flow rule were adopted to consider the viscoplastic deformation in the EDZ. A relation between volumetric strain and permeability was established. Using a self-developed EPCA2D code, the elastic, elasto-plastic and creep analyses to study the evolution of stress and deformations, as well as failure and permeability evolution in the EDZ were conducted. Results indicate a strong impact of fractures, plastic deformation and time effects on the behavior of EDZ especially the evolution of permeability around the drift.

A Feeding Strategy in Inner L-Shape Ring Hot Rolling Process

Directory of Open Access Journals (Sweden)

Wen Meng

2017-01-01

Full Text Available In order to make the inner L-shape ring polling process with a closed die structure (ILRRCDS on the top and bottom of the driven roll stable, at first, this paper established the mathematical model for ILRRCDS. Then, the plastic penetration and biting-in conditions for ILRRCDS were deduced based on plain ring rolling theory. Moreover, a feeding strategy that can realize a constant growth of the ring’s outer radius was proposed and the reasonable value ranges of the feed rate of the mandrel were determined. The numerical simulation model for ILRRCDS is established based on ABAQUS software. Finally, the equivalent plastic strain (PEEQ and temperature distributions of rolled ring were obtained. The results indicated that the proposed feeding strategy can realize a stable ILRRCDS. At the end of ILRRCDS, the PEEQ at the inner radius surface of the ring is maximum, the PEEQ at the outer radius surface of the ring takes the second place, and the PEEQ at the middle part of ring is minimum. With the increase of rolling time, the higher temperature zone of the rolled ring gradually moves from the center part of the ring to the “inner corner zone” of the ring.

Plastic pollution in the Labrador Sea: An assessment using the seabird northern fulmar Fulmarus glacialis as a biological monitoring species.

Science.gov (United States)

Avery-Gomm, Stephanie; Provencher, Jennifer F; Liboiron, Max; Poon, Florence E; Smith, Paul A

2018-02-01

Plastic is now one among one of the most pervasive pollutants on the planet, and ocean circulation models predict that the Arctic will become another accumulation zone. As solutions to address marine plastic emerge, is essential that baselines are available to monitor progress towards targets. The northern fulmar (Fulmarus glacialis), a widely-distributed seabird species, has been used as a biological monitor for plastic pollution in the North Sea, and could be a useful monitoring species elsewhere. We quantified plastic ingested by northern fulmars from the southeastern Canadian waters of the Labrador Sea with the objective of establishing a standardized baseline for future comparisons. Over two years we sampled 70 fulmars and found that 79% had ingested plastic, with an average of 11.6 pieces or 0.151g per bird. Overall, 34% of all fulmars exceeded the Ecological Quality Objective for marine litter, having ingested >0.1g of plastic. Copyright © 2017 Elsevier Ltd. All rights reserved.

Factors associated with infection following open distal radius fractures.

Science.gov (United States)

Glueck, Dane A; Charoglu, Constantine P; Lawton, Jeffrey N

2009-09-01

Open fractures are often classified according to a system described by Gustilo and Anderson. However, this system was applied to open long bone fractures, which may not predict the incidence of infection in open metaphyseal fractures of the upper extremity. Other studies have found that wound contamination and systemic illness were the best predictors of infections in open hand fractures. Our study assessed infection in open distal radius fractures and identifies factors that are associated with these infections. We hypothesize that contamination, rather than absolute wound size, is the best predictor of infection associated with open distal radius fractures. A review by CPT code yielded 42 patients with open distal radius fractures between 1997 and 2002 treated at a level one trauma center. Medical records and radiographic follow-up were reviewed to assess the time to irrigation and debridement, the number of debridements in initial treatment period, the method of operative stabilization, the Gustilo and Anderson type of fracture, the Swanson type of fracture, and description of wound contamination. Forty-two patients were followed up for an average of 15 months (range 4 to 68 months). Twenty-four fractures were classified as Gustilo and Anderson type I, ten were type II, and eight were type III, 30 were Swanson type I, and 12 were Swanson type II. Five of the 42 fractures were considered contaminated. Two were exposed to fecal contamination. The others were contaminated with tar, dirt/grass, and gravel, respectively. Three of 42 (7%) fractures developed infections. All three infected cases received a single irrigation and debridement. Two of five contaminated fractures (40%) developed a polymicrobial infection. Both were exposed to fecal contamination and, therefore, considered Swanson type II fractures. They were classified as Gustilo and Anderson type II and IIIB based solely upon the size of the wound. Both required multiple debridements and eventually wrist

Radon exhalation rate on the Sivrice (Elazig ) fault zone

International Nuclear Information System (INIS)

Sahin, S.; Kuluoeztuerk, M. F.; Dogru, M.

2009-01-01

Four radon monitoring stations were built on the Sivrice Fault Zone which is a part of the East Anatolian Fault System that one of the very important two fault systems which tends to produce earthquake in Turkey. Radon exhalation rate were analyzed in the soil and water samples which collected around the stations. Radon exhalation rate in the soil and water samples were determined by using CR-39 that it is plastic detector.

The effect of adhesion on the contact radius in atomic force microscopy indentation

International Nuclear Information System (INIS)

Sirghi, L; Rossi, F

2009-01-01

The effect of adhesion on nanoscale indentation experiments makes the interpretation of force-displacement curves acquired in these experiments very difficult. The indentation force results from the addition of adhesive and elastic forces at the indenter-sample contact. The evolution of the two forces during the indentation is determined by the variation of the indenter-sample contact radius. In the present work the variation of contact radius during atomic force microscopy (AFM) indentation of elastic and adhesive samples with conical indenters (AFM tips) is indirectly determined by measurements of the contact dynamic stiffness. For weak sample deformations, the contact radius is determined mainly by the adhesion force and indenter apex radius. For strong sample deformations, the contact radius increases linearly with the increase of the indenter displacement, the slope of this linear dependence being in agreement with Sneddon's theory of indentation (Sneddon 1965 Int. J. Eng. Sci. 3 47). Based on these results, a theoretical expression of indentation force dependence on displacement is found. This expression allows for determination of the thermodynamic work of adhesion at the indenter-sample interface and the sample elasticity modulus.

High order curvilinear finite elements for elastic–plastic Lagrangian dynamics

International Nuclear Information System (INIS)

Dobrev, Veselin A.; Kolev, Tzanio V.; Rieben, Robert N.

2014-01-01

This paper presents a high-order finite element method for calculating elastic–plastic flow on moving curvilinear meshes and is an extension of our general high-order curvilinear finite element approach for solving the Euler equations of gas dynamics in a Lagrangian frame [1,2]. In order to handle transition to plastic flow, we formulate the stress–strain relation in rate (or incremental) form and augment our semi-discrete equations for Lagrangian hydrodynamics with an additional evolution equation for the deviatoric stress which is valid for arbitrary order spatial discretizations of the kinematic and thermodynamic variables. The semi-discrete equation for the deviatoric stress rate is developed for 2D planar, 2D axisymmetric and full 3D geometries. For each case, the strain rate is approximated via a collocation method at zone quadrature points while the deviatoric stress is approximated using an L 2 projection onto the thermodynamic basis. We apply high order, energy conserving, explicit time stepping methods to the semi-discrete equations to develop the fully discrete method. We conclude with numerical results from an extensive series of verification tests that demonstrate several practical advantages of using high-order finite elements for elastic–plastic flow

Dynamic elastic-plastic behaviour of a frame including coupled bending and torsion

International Nuclear Information System (INIS)

Messmer, S.; Sayir, M.

1989-01-01

The full time response of a space frame under impact loading perpendicular to the frame plane is discussed. Theoretical solutions and experimental results are presented and compared. A space frame clamped at its two ends is loaded by a 0.22 lead bullet that hits a mass in the middle of the transversal beam of the frame. The loading time is about 40 to 60 μs and the resulting linear momentum of the impact in the experiment is 0.5 to 1 N s. The time response of this frame can be divided in four phases where different physical effects are dominant: (a) The loading phase where elastic wave motion dominates the time response. Because of the high impact forces, plastic deformation occurs in the vicinity of the mass and must be included in a theoretical model. The influence of reflections at the corners on the time response is shown in theory and experiment. (b) The evolution phase. Within this phase, a plastic collapse mechanism develops. Most of this phase is dominated by elastic deformation but local plastic deformations beside the mass are also present. Because many reflections at corners, clamps and the mass occur within this phase, a modal analysis method is used to predict time histories. (c) The plastic phase with plastic zones at the clamps. The phase sets in after the bending wave reaches the clamps. It is characterized by plastic deformation near the clamps and elastic deformation of the other parts of the frame. We used a modal analysis including plastic 'modes' to get accurate results. (d) The elastic vibration phase

Observation of the Spectrally Invariant Properties of Clouds in Cloudy-to-Clear Transition Zones During the MAGIC Field Campaign

Science.gov (United States)

Yang, Weidong; Marshak, Alexander; McBride, Patrick; Chiu, J. Christine; Knyazikhin, Yuri; Schmidt, K. Sebastian; Flynn, Connor; Lewis, Ernie R.; Eloranta, Edwin W.

2016-01-01

We use the spectrally invariant method to study the variability of cloud optical thickness tau and droplet effective radius r(sub eff) in transition zones (between the cloudy and clear sky columns) observed from Solar Spectral Flux Radiometer (SSFR) and Shortwave Array Spectroradiometer-Zenith (SASZe) during the Marine ARM GPCI Investigation of Clouds (MAGIC) field campaign. The measurements from the SSFR and the SASZe are different, however inter-instrument differences of self-normalized measurements (divided by their own spectra at a fixed time) are small. The spectrally invariant method approximates the spectra in the cloud transition zone as a linear combination of definitely clear and cloudy spectra, where the coefficients, slope and intercept, characterize the spectrally invariant properties of the transition zone. Simulation results from the SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer) model demonstrate that (1) the slope of the visible band is positively correlated with the cloud optical thickness t while the intercept of the near-infrared band has high negative correlation with the cloud drop effective radius r(sub eff)even without the exact knowledge of tau; (2) the above relations hold for all Solar Zenith Angle (SZA) and for cloud-contaminated skies. In observations using redundant measurements from SSFR and SASZe, we find that during cloudy-to-clear transitions, (a) the slopes of the visible band decrease, and (b) the intercepts of the near-infrared band remain almost constant near cloud edges. The findings in simulations and observations suggest that, while the optical thickness decreases during the cloudy-to-clear transition, the cloud drop effective radius does not change when cloud edges are approached. These results support the hypothesis that inhomogeneous mixing dominates near cloud edges in the studied cases.

Crystal-plastic deformation of zircon : effects on microstructures, textures, microchemistry and the retention of radiogenic isotopes

International Nuclear Information System (INIS)

Kovaleva, E.

2015-01-01

Dating of deep-crustal deformation events potentially can be achieved by using plastically-deformed accessory minerals found in high-temperature shear zones. Deformation microstructures, such as dislocations and low-angle boundaries, form due to plastic deformation in the crystal lattice and act as fluid migration pathways and trace element (e.g. Pb, Ti, U, Th, REE) diffusion pathways through so-called “pipe diffusion”. Deformation microstructures can alter the chemical and isotopic composition of certain grain parts and may lead to complete or partial isotopic resetting of certain geochronometers (e.g. U/Th/Pb, K/Ar, Rb/Sr) in the mineral domains. This work aims to better understand the processes of crystal-plastic deformation and associated trace element redistribution and the resetting of isotopic systems in zircon. This study finds that: a) there are three general finite deformation patterns in deformed zircons; b) suggests that it is possible to reconstruct the macroscopic kinematic framework of the shear zone based on the orientation of deformed zircon grains and the operating misorientation axes; c) and demonstrates the effect of deformation microstructures on trace elements and Pb isotopes in zircon. The final goal of this project is to develop a tool for isotopic dating of high-temperature deformation events in the deep crust. In addition to these results, zircon grains with planar deformation bands have been discovered in paleo-seismic zones; these deformation features have been described in detail and a possible mechanism of their origin and formation is suggested. The effect of planar deformation bands on trace element and isotopic behavior has also been investigated. (author) [de

The white dwarf mass-radius relation with Gaia, Hubble and FUSE

Science.gov (United States)

Joyce, Simon R. G.; Barstow, Martin A.; Casewell, Sarah L.; Holberg, Jay B.; Bond, Howard E.

2018-04-01

White dwarfs are becoming useful tools for many areas of astronomy. They can be used as accurate chronometers over Gyr timescales. They are also clues to the history of star formation in our galaxy. Many of these studies require accurate estimates of the mass of the white dwarf. The theoretical mass-radius relation is often invoked to provide these mass estimates. While the theoretical mass-radius relation is well developed, observational tests of this relation show a much larger scatter in the results than expected. High precision observational tests to confirm this relation are required. Gaia is providing distance measurements which will remove one of the main source of uncertainty affecting most previous observations. We combine Gaia distances with spectra from the Hubble and FUSE satelites to make precise tests of the white dwarf mass-radius relation.

Aplikasi Pencarian Tempat Wisata Berbasiskan GPS dengan Metode Radius dan Rating

Directory of Open Access Journals (Sweden)

Budi Yulianto

2015-03-01

Full Text Available Tourist place navigation application becomes more important for travelers, especially backpackers. Previous research had produced applications which can only show the route from the position of traveler to tourist place with map shown. The goal of the research is to use the radius and rating method that is still rare in the community to navigate tourist place. Output of the research is a GPS-based application that can display the search results of tourist sites based on rating and radius method, route from the traveler to the destination place, and description of the place. Development method used waterfall that contained user requirement, analysis, design, coding and testing, implementation, and maintenance. Conclusion of the research has shown that the developed application provided convenience in searching tourist places based on radius and rating, displaying route, and description of tourist places.

Strain mapping under spherical indentations using transmission Kikuchi diffraction

International Nuclear Information System (INIS)

Cackett, A.; Hardie, C.; Wilkinson, A.; Dicks, K.

2015-01-01

Due to restrictions on both the specimen volumes available and the activity levels research facilities can handle, testing techniques on the micron-scale are very attractive for the study of irradiated material. However, the results of such small tests are convoluted by plasticity size-effects. Spherical nano-indentation is increasingly used to probe irradiated material, but to characterise the area of plastic deformation surrounding indentations a method capable of providing crystallographic information at extremely high spatial resolution is required. Transmission Kikuchi Diffraction (TKD) is a novel diffraction technique that can be performed in a scanning electron microscope. Using this technique, spatial resolutions below 10 nm have been achieved. Initial results, shown here, demonstrate the use of TKD in mapping the lattice rotations caused by indentation produced with a spherical diamond tip. With the addition of strain mapping software the plastic zone size was also evaluated for the first time using diffraction patterns generated via TKD. For a tip of radius 15 μm, inserted into Fe to a strain of 0.07, the plastic zone was observed to extend 1.3 μm to either side of the incident location of indentation and the deformation depth was approximately 0.5 μm. (authors)

plastic waste recycling

African Journals Online (AJOL)

Dr Ahmed

incinerators is increasing around the world. Discarded plastic products ... Agency (EPA) estimated that the amount of plastics throw away is. 50 % greater in the ... The waste plastics were identified using the Society of the Plastic. Industry (SPI) ...

The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

KAUST Repository

Cózar, Andrés

2017-04-20

The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively sampled for floating plastic debris from the Tara Oceans circumpolar expedition. Although plastic debris was scarce or absent in most of the Arctic waters, it reached high concentrations (hundreds of thousands of pieces per square kilometer) in the northernmost and easternmost areas of the Greenland and Barents seas. The fragmentation and typology of the plastic suggested an abundant presence of aged debris that originated from distant sources. This hypothesis was corroborated by the relatively high ratios of marine surface plastic to local pollution sources. Surface circulation models and field data showed that the poleward branch of the Thermohaline Circulation transfers floating debris from the North Atlantic to the Greenland and Barents seas, which would be a dead end for this plastic conveyor belt. Given the limited surface transport of the plastic that accumulated here and the mechanisms acting for the downward transport, the seafloor beneath this Arctic sector is hypothesized as an important sink of plastic debris.

Indentation size effects in single crystal copper as revealed by synchrotron x-ray microdiffraction

Science.gov (United States)

Feng, G.; Budiman, A. S.; Nix, W. D.; Tamura, N.; Patel, J. R.

2008-08-01

For a Cu single crystal, we find that indentation hardness increases with decreasing indentation depth, a phenomenon widely observed before and called the indentation size effect (ISE). To understand the underlying mechanism, we measure the lattice rotations in indentations of different sizes using white beam x-ray microdiffraction (μXRD); the indentation-induced lattice rotations are directly measured by the streaking of x-ray Laue spots associated with the indentations. The magnitude of the lattice rotations is found to be independent of indentation size, which is consistent with the basic tenets of the ISE model. Using the μXRD data together with an ISE model, we can estimate the effective radius of the indentation plastic zone, and the estimate is consistent with the value predicted by a finite element analysis. Using these results, an estimate of the average dislocation densities within the plastic zones has been made; the findings are consistent with the ISE arising from a dependence of the dislocation density on the depth of indentation.

Artificial gravity: head movements during short-radius centrifugation

NARCIS (Netherlands)

Young, L. R.; Hecht, H.; Lyne, L. E.; Sienko, K. H.; Cheung, C. C.; Kavelaars, J.

2001-01-01

Short-radius centrifugation is a potential countermeasure to long-term weightlessness. Unfortunately, head movements in a rotating environment induce serious discomfort, non-compensatory vestibulo-ocular reflexes, and subjective illusions of body tilt. In two experiments we investigated the effects

Elucidating the atomistic mechanisms underpinning plasticity in Li-Si nanostructures

Science.gov (United States)

Yan, Xin; Gouissem, Afif; Guduru, Pradeep R.; Sharma, Pradeep

2017-10-01

Amorphous lithium-silicon (a-Li-Si), especially in nanostructure form, is an attractive high-capacity anode material for next-generation Li-ion batteries. During cycles of charging and discharging, a-Li-Si undergoes substantive inelastic deformation and exhibits microcracking. The mechanical response to repeated lithiation-delithiation eventually results in the loss of electrical contact and consequent decrease of capacity, thus underscoring the importance of studying the plasticity of a-Li-Si nanostructures. In recent years, a variety of phenomenological continuum theories have been introduced that purport to model plasticity and the electro-chemo-mechanical behavior of a-Li-Si. Unfortunately, the micromechanisms and atomistic considerations underlying plasticity in Li-Si material are not yet fully understood and this impedes the development of physics-based constitutive models. Conventional molecular dynamics, although extensively used to study this material, is grossly inadequate to resolve this matter. As is well known, conventional molecular dynamics simulations can only address phenomena with characteristic time scales of (at most) a microsecond. Accordingly, in such simulations, the mechanical behavior is deduced under conditions of very high strain rates (usually, 108s-1 or even higher). This limitation severely impacts a realistic assessment of rate-dependent effects. In this work, we attempt to circumvent the time-scale bottleneck of conventional molecular dynamics and provide novel insights into the mechanisms underpinning plastic deformation of Li-Si nanostructures. We utilize an approach that allows imposition of slow strain rates and involves the employment of a new and recently developed potential energy surface sampling method—the so-called autonomous basin climbing—to identify the local minima in the potential energy surface. Combined with other techniques, such as nudged elastic band, kinetic Monte Carlo and transition state theory, we assess

QED confronts the radius of the proton

CERN Document Server

De Rujula, A

2011-01-01

Recent results on muonic hydrogen [1] and the ones compiled by CODATA on ordinary hydrogen and $ep$-scattering [2] are $5\\sigma$ away from each other. Two reasons justify a further look at this subject: 1) One of the approximations used in [1] is not valid for muonic hydrogen. This amounts to a shift of the proton's radius by $\\sim 3$ of the standard deviations of [1], in the "right" direction of data-reconciliation. In field-theory terms, the error is a mismatch of renormalization scales. Once corrected, the proton radius "runs", much as the QCD coupling "constant" does. 2) The result of [1] requires a choice of the "third Zemach moment". Its published independent determination is based on an analysis with a $p$-value --the probability of obtaining data with equal or lesser agreement with the adopted (fit form-factor) hypothesis-- of $3.92\\times 10^{-12}$. In this sense, this quantity is not empirically known. Its value would regulate the level of "tension" between muonic- and ordinary-hydrogen results, curr...

Direct liquefaction of plastics and coprocessing of coal with plastics

Energy Technology Data Exchange (ETDEWEB)

Huffman, G.P.; Feng, Z.; Mahajan, V. [Univ. of Kentucky, Lexington, KY (United States)

1995-12-31

The objectives of this work were to optimize reaction conditions for the direct liquefaction of waste plastics and the coprocessing of coal with waste plastics. In previous work, the direct liquefaction of medium and high density polyethylene (PE), polypropylene (PPE), poly(ethylene terephthalate) (PET), and a mixed plastic waste, and the coliquefaction of these plastics with coals of three different ranks was studied. The results established that a solid acid catalyst (HZSM-5 zeolite) was highly active for the liquefaction of the plastics alone, typically giving oil yields of 80-95% and total conversions of 90-100% at temperatures of 430-450 {degrees}C. In the coliquefaction experiments, 50:50 mixtures of plastic and coal were used with a tetralin solvent (tetralin:solid = 3:2). Using approximately 1% of the HZSM-5 catalyst and a nanoscale iron catalyst, oil yields of 50-70% and total conversion of 80-90% were typical. In the current year, further investigations were conducted of the liquefaction of PE, PPE, and a commingled waste plastic obtained from the American Plastics Council (APC), and the coprocessing of PE, PPE and the APC plastic with Black Thunder subbituminous coal. Several different catalysts were used in these studies.

Mercury's radius change estimates revisited using high incidence angle MESSENGER data

Science.gov (United States)

Di Achille, G.; Popa, C.; Massironi, M.; Ferrari, S.; Mazzotta Epifani, E.; Zusi, M.; Cremonese, G.; Palumbo, P.

2012-04-01

Estimates of Mercury's radius decrease obtained using the amount of strain recorded by tectonics on the planet range from 0.5 km to 2 km. These latter figures appear too low with respect to the radius contraction (up to 5-6 km) predicted by the most accredited studies based on thermo-mechanical evolution models. For this reason, it has been suggested that there may be hidden strain accommodated by features yet unseen on Mercury. Indeed, as it has been already cautioned by previous studies, the identification of tectonic features on Mercury might be largely biased by the lighting geometry of the used basemaps. This limitation might have affected the results of the extrapolations for estimating the radius change. In this study, we mapped tectonic features at the terminator thus using images acquired at high sun incidence angle (>50°) that represents the optimal condition for their observation. In fact, images with long shadows enhance the topography and texture of the surface and are ideal to detect tectonic structures. This favorable illumination conditions allowed us to infer reliable measurements of spatial distribution (i.e. frequency, orientation, and areal density) of tectonic features which can be used to estimate the average contractional strain and planetary radius decrease. We digitized tectonic structures within a region extending for an area of about 12 million sq. km (~16% of planet's surface). More than 1300 tectonic lineaments were identified and interpreted to be compressional features (i.e. lobate scarps, wrinkle ridges, and high relief ridges) with a total length of more than 12300 km. Assuming that the extensional strain is negligible within the area, the average contractional strain calculated for the survey area is ~0.21-0.28% (~0.24% for θ=30°). This strain, extrapolated to the entire surface, corresponds to a contraction in radius of about 2.5-3.4 km (~2.9 km for θ=30°). Interestingly, the values of contractional strain and radius decrease

"Oriental anthropometry" in plastic surgery

Directory of Open Access Journals (Sweden)

Senna-Fernandes Vasco

2008-01-01

Full Text Available Background : According to Chinese medicine, the acupuncture-points′ (acupoints locations are proportionally and symmetrically distributed in well-defined compartment zones on the human body surface Oriental Anthropometry" (OA. Acupoints, if considered as aesthetic-loci, might be useful as reference guides in plastic surgery (PS. Aim: This study aimed to use aesthetic-loci as anatomical reference in surgical marking of Aesthetic Plastic Surgery. Method: This was an observational study based on aesthetic surgeries performed in private clinic. This study was based on 106 cases, comprising of 102 women and 4 men, with ages varying from 07 to 73 years, and with heights of between 1.34 m and 1.80 m. Patients were submitted to aesthetic surgical planning by relating aesthetic-loci to conventional surgical marking, including breast surgeries, abdominoplasty, rhytidoplasty, blepharoplasty, and hair implant. The aesthetic-surgical-outcome (ASO of the patients was assessed by a team of plastic surgeons (who were not involved in the surgical procedures over a follow-up period of one year by using a numeric-rating-scale in percentage (% terms. A four-point-verbal-rating-scale was used to record the patients′ opinion of therapeutic-satisfaction (TS. Results: ASO was 75.3 ± 9.4% and TS indicated that most patients (58.5% obtained "good" results. Of the remainder, 38.7% found the results "excellent", and 2.8% found them "fair". Discussion and Conclusion : The data suggested that the use of aesthetic-loci may be a useful tool for PS as an anatomical reference for surgical marking. However, further investigation is required to assess the efficacy of the OA by providing the patients more reliable balance and harmony in facial and body contours surgeries.

Relation between second-order moment radius of focal spot and near field distribution of laser beam

International Nuclear Information System (INIS)

Gao Xueyan; Su Yi; Ye Yidong; Guan Youguang

2011-01-01

In order to analyze the effect of aberration of amplitude and phase of laser beam on second-order moment radius of focal spot, based on the Fraunhofer formula for light wave scalar diffraction theory and the definition of second-order moment radius, the general expression for focal spot second-order moment radius depending on the complex amplitude of near field is derived. The second-order moment radius of the focal spot depending on intensity distribution and phase distribution of near field is derived, and its clear physical meaning is described. The second-order moment radius and the divergence angle of focal spot may be easily calculated with the second-order moment radius expression of focal spot. At last, the divergence angles of focal spots of several kinds of Gaussian laser beams are calculated directly, and the results are in accordance with those in the related references. (authors)

Maximum wind radius estimated by the 50 kt radius: improvement of storm surge forecasting over the western North Pacific

Science.gov (United States)

Takagi, Hiroshi; Wu, Wenjie

2016-03-01

Even though the maximum wind radius (Rmax) is an important parameter in determining the intensity and size of tropical cyclones, it has been overlooked in previous storm surge studies. This study reviews the existing estimation methods for Rmax based on central pressure or maximum wind speed. These over- or underestimate Rmax because of substantial variations in the data, although an average radius can be estimated with moderate accuracy. As an alternative, we propose an Rmax estimation method based on the radius of the 50 kt wind (R50). Data obtained by a meteorological station network in the Japanese archipelago during the passage of strong typhoons, together with the JMA typhoon best track data for 1990-2013, enabled us to derive the following simple equation, Rmax = 0.23 R50. Application to a recent strong typhoon, the 2015 Typhoon Goni, confirms that the equation provides a good estimation of Rmax, particularly when the central pressure became considerably low. Although this new method substantially improves the estimation of Rmax compared to the existing models, estimation errors are unavoidable because of fundamental uncertainties regarding the typhoon's structure or insufficient number of available typhoon data. In fact, a numerical simulation for the 2013 Typhoon Haiyan as well as 2015 Typhoon Goni demonstrates a substantial difference in the storm surge height for different Rmax. Therefore, the variability of Rmax should be taken into account in storm surge simulations (e.g., Rmax = 0.15 R50-0.35 R50), independently of the model used, to minimize the risk of over- or underestimating storm surges. The proposed method is expected to increase the predictability of major storm surges and to contribute to disaster risk management, particularly in the western North Pacific, including countries such as Japan, China, Taiwan, the Philippines, and Vietnam.

Synchronous Multicentric Giant Cell Tumour of Distal Radius and Sacrum with Pulmonary Metastases

Directory of Open Access Journals (Sweden)

Varun Sharma Tandra

2015-01-01

Full Text Available Giant cell tumour (GCT is an uncommon primary bone tumour, and its multicentric presentation is exceedingly rare. We report a case of a 45-year-old female who presented to us with GCT of left distal radius. On the skeletal survey, osteolytic lesion was noted in her right sacral ala. Biopsy confirmed both lesions as GCT. Pulmonary metastasis was also present. Resection-reconstruction arthroplasty for distal radius and thorough curettage and bone grafting of the sacral lesion were done. Multicentric GCT involving distal radius and sacrum with primary sacral involvement is not reported so far to our knowledge.

Bounds of the Spectral Radius and the Nordhaus-Gaddum Type of the Graphs

Directory of Open Access Journals (Sweden)

Tianfei Wang

2013-01-01

Full Text Available The Laplacian spectra are the eigenvalues of Laplacian matrix L(G=D(G-A(G, where D(G and A(G are the diagonal matrix of vertex degrees and the adjacency matrix of a graph G, respectively, and the spectral radius of a graph G is the largest eigenvalue of A(G. The spectra of the graph and corresponding eigenvalues are closely linked to the molecular stability and related chemical properties. In quantum chemistry, spectral radius of a graph is the maximum energy level of molecules. Therefore, good upper bounds for the spectral radius are conducive to evaluate the energy of molecules. In this paper, we first give several sharp upper bounds on the adjacency spectral radius in terms of some invariants of graphs, such as the vertex degree, the average 2-degree, and the number of the triangles. Then, we give some numerical examples which indicate that the results are better than the mentioned upper bounds in some sense. Finally, an upper bound of the Nordhaus-Gaddum type is obtained for the sum of Laplacian spectral radius of a connected graph and its complement. Moreover, some examples are applied to illustrate that our result is valuable.

[The detector, the command neuron and plastic convergence].

Science.gov (United States)

Sokolov, E N

1977-01-01

The paper deals with the structure of detectors, the function of commanding neurones and the problem of relationship between detectors and commanding neurons. An example of hierarchial organization of detectors is provided by the colour analyser in which a layer of receptors, a layer of opponent neurones and a layer of colour-selective detectors are singled out. The colour detector is selectively sensitive to a certain combination of excitations at the input. If the detector is selectively activated by a certain combination of excitations at the input, the selective activation of the commanding neurone through a pool of motoneurones brings about a reaction at the output, specific in its organization. The reflexogenic zone of the reaction is determined by the detectors which converge on the commanding neurone controlling the given reaction. The plasticity of the reaction results from a plastic convergence of the detectors on the commanding neurone which controls the reaction. This comprises selective switching off the detectors from the commanding neurone (habituation) and connecting the detectors to the commanding neurone (facilitation).

Recycling of Plastic

DEFF Research Database (Denmark)

Christensen, Thomas Højlund; Fruergaard, Thilde

2011-01-01

Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like...

Rational functions with maximal radius of absolute monotonicity

KAUST Repository

Loczi, Lajos; Ketcheson, David I.

2014-01-01

-Kutta methods for initial value problems and the radius of absolute monotonicity governs the numerical preservation of properties like positivity and maximum-norm contractivity. We construct a function with p=2 and R>2s, disproving a conjecture of van de Griend

Thrombocytopenia-absent radius syndrome: a clinical genetic study.

NARCIS (Netherlands)

Greenhalgh, K.L.; Howell, R.; Bottani, A.; Ancliff, P.J.; Brunner, H.G.; Verschuuren-Bemelmans, C.C.; Vernon, E.; Brown, K.W.; Newbury-Ecob, R.

2002-01-01

The thrombocytopenia-absent radius (TAR) syndrome is a congenital malformation syndrome characterised by bilateral absence of the radii and a thrombocytopenia. The lower limbs, gastrointestinal, cardiovascular, and other systems may also be involved. Shaw and Oliver in 1959 were the first to

Thrombocytopenia-absent radius syndrome : a clinical genetic study

NARCIS (Netherlands)

Greenhalgh, KL; Howell, RT; Bottani, A; Ancliff, PJ; Brunner, HG; Verschuuren-Bemelmans, CC; Vernon, E; Brown, KW; Newbury-Ecob, RA

2002-01-01

The thrombocytopenia-absent radius (TAR) syndrome is a congenital malformation syndrome characterised by bilateral absence of the radii and a thrombocytopenia. The lower limbs, gastrointestinal, cardiovascular, and other systems may also be involved. Shaw and Oliver in 1959 were the first to

A Non-Interfering Beam Radius Diagnostic Suitable For Induction Linacs

International Nuclear Information System (INIS)

Nexsen, W E

2005-01-01

High current electron induction linacs operate in a parameter regime that allows the use of a diamagnetic loop (DML) to measure the beam magnetic moment. Under certain easily met conditions the beam radius can be derived from the moment measurement. The DML has the advantage over the present methods of measuring beam radius in that it is an electrical measurement with good time resolution that does not interfere with the beam transport. I describe experiments on the LLNL accelerators, ETA-II and FXR that give confidence in the use of a DML as a beam diagnostic

Relationship between plate removal and Soong grading following surgery for fractured distal radius

NARCIS (Netherlands)

Selles, Caroline A.; Reerds, Sam T. H.; Roukema, Gert; van der Vlies, Kees H.; Cleffken, Berry I.; Schep, Niels W. L.

2018-01-01

The aim of this study was to determine the relationship between volar plate removal and the Soong classification following fixation for fractured distal radius. In this retrospective cohort study, all consecutive patients who had volar plate fixation for a distal radius fracture in 2011-2015 were

Study on Oneself Developed to Apparatus Position of Measurement of BMD in the Distal Radius

International Nuclear Information System (INIS)

Han, Man Seok; Song, Jae Yong; Lee, Hyun Kuk; Yu, Se Jong; Kim, Yong Kyun

2009-01-01

The aim of this study was to evaluate the difference of bone mineral density according to distal radius rotation and to develop the supporting tool to measure rotation angles. CT scanning and the measurement of BMD by DXA of the appropriate position of the forearm were performed on 20 males. Twenty healthy volunteers without any history of operations, anomalies, or trauma were enrolled. The CT scan was used to evaluate the cross sectional structure and the rotation angle on the horizontal plane of the distal radius. The rotational angle was measured by the m-view program on the PACS monitor. The DXA was used in 20 dried radii of cadaveric specimens in pronation and supination with five and ten degrees, respectively, including a neutral position (zero degrees) to evaluate the changes of BMD according to the rotation. The mean rotation angle of the distal radius on CT was 7.4 degrees of supination in 16 cases (80%), 3.3 degrees of pronation in three cases (15%), and zero degree of neutral in one case (9%), respectively. The total average rotation angle in 20 people was 5.4 degrees of supination. In the cadaveric study, the BMD of the distal radius was different according to the rotational angles. The lowest BMD was obtained at 3.3 degrees of supination. In the case of the measurement of BMD in the distal radius with a neutral position, the rotational angle of the distal radius is close to supination. Pronation is needed for the constant measurement of BMD in the distal radius with the rotation angle measuring at the lowest BMD and about five degrees of pronation of the distal radius is recommended.

Strain localization and elastic-plastic coupling during deformation of porous sandstone

Energy Technology Data Exchange (ETDEWEB)

Dewers, Thomas A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Issen, Kathleen A. [Clarkson Univ., Potsdam, NY (United States). Mechanical and Aeronautical Engineering; Holcomb, David J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Olsson, William A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Ingraham, Mathew D. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.

2017-09-12

Results of axisymmetric compression tests on weak, porous Castlegate Sandstone (Cretaceous, Utah, USA), covering a range of dilational and compactional behaviors, are examined for localization behavior. Assuming isotropy, bulk and shear moduli evolve as increasing functions of mean stress and Mises equivalent shear stress respectively, and as decreasing functions of work-conjugate plastic strains. Acoustic emissions events located during testing show onset of localization and permit calculation of observed shear and low-angle compaction localization zones, or bands, as localization commences. Total strain measured experimentally partitions into: A) elastic strain with constant moduli, B) elastic strain due to stress dependence of moduli, C) elastic strain due to moduli degradation with increasing plastic strain, and D) plastic strain. The third term is the elastic-plastic coupling strain, and though often ignored, contributes significantly to pre-failure total strain for brittle and transitional tests. Constitutive parameters and localization predictions derived from experiments are compared to theoretical predictions. In the brittle regime, predictions of band angles (angle between band normal and maximum compression) demonstrate good agreement with observed shear band angles. Compaction localization was observed in the transitional regime in between shear localization and spatially pervasive compaction, over a small range of mean stresses. In contrast with predictions however, detailed acoustic emissions analyses in this regime show low angle, compaction-dominated but shear-enhanced, localization.

Utility of radius bone densitometry for the treatment of osteoporosis with once-weekly teriparatide therapy

Directory of Open Access Journals (Sweden)

Harumi Nakayama

2018-03-01

Full Text Available Objectives: As clinics that treat patients with osteoporosis do not usually have central dual-energy X-ray absorptiometry (DXA, bone density is often measured with radial DXA. However, no long-term evidence exists for radius bone density outcomes following treatment with once-weekly teriparatide in actual medical treatment. Methods: We evaluated changes in bone density at 6-, 12-, and 18-month intervals using radial DXA in patients treated with once-weekly teriparatide for more than 6 months. Results: A significant increase in bone mineral density (BMD was observed at the 1/3 and 1/10 radius sites 12 months after the initiation of once-weekly teriparatide. We also observed that the rate of change in BMD was greater at the distal 1/10 radius than at the 1/3 radius. Conclusions: Considering these points, the effect of once-weekly teriparatide therapy can be observed at the radius. In clinics that do not have central DXA, but instead have radial DXA, these findings can help to evaluate the effect of once-weekly teriparatide treatment on osteoporosis. Keywords: Once-weekly teriparatide, Osteoporosis, Radius, Dual-energy X-ray absorptiometry

Fractal analysis of bone architecture at distal radius

International Nuclear Information System (INIS)

Tomomitsu, Tatsushi; Mimura, Hiroaki; Murase, Kenya; Sone, Teruki; Fukunaga, Masao

2005-01-01

Bone strength depends on bone quality (architecture, turnover, damage accumulation, and mineralization) as well as bone mass. In this study, human bone architecture was analyzed using fractal image analysis, and the clinical relevance of this method was evaluated. The subjects were 12 healthy female controls and 16 female patients suspected of having osteoporosis (age range, 22-70 years; mean age, 49.1 years). High-resolution CT images of the distal radius were acquired and analyzed using a peripheral quantitative computed tomography (pQCT) system. On the same day, bone mineral densities of the lumbar spine (L-BMD), proximal femur (F-BMD), and distal radius (R-BMD) were measured by dual-energy X-ray absorptiometry (DXA). We examined the correlation between the fractal dimension and six bone mass indices. Subjects diagnosed with osteopenia or osteoporosis were divided into two groups (with and without vertebral fracture), and we compared measured values between these two groups. The fractal dimension correlated most closely with L-BMD (r=0.744). The coefficient of correlation between the fractal dimension and L-BMD was very similar to the coefficient of correlation between L-BMD and F-BMD (r=0.783) and the coefficient of correlation between L-BMD and R-BMD (r=0.742). The fractal dimension was the only measured value that differed significantly between both the osteopenic and the osteoporotic subjects with and without vertebral fracture. The present results suggest that the fractal dimension of the distal radius can be reliably used as a bone strength index that reflects bone architecture as well as bone mass. (author)

Elastic-plastic FEM-analysis of a nozzle corner crack and discussion of the results by some fracture mechanics concepts

International Nuclear Information System (INIS)

Aurich, D.; Brocks, W.; Noack, D.; Veith, H.

1981-01-01

From a three-dimensional elastic-plastic stress-distortion analysis according to the finite element method (FEM) for a straight inner edge crack at room temperature in a nozzle of the intermediate vessel ZB 2 made of 22 NiMoCr 37 steel, the results obtained for stresses and strains in the ligament before the crack front, the crack opening profile, and the propagation of the plastic zone as a function of internal pressure until through-plastifying of the ligament are shown and explained. (orig.) [de

Initialization effects via the nuclear radius on transverse in-plane flow and its disappearance

Directory of Open Access Journals (Sweden)

Bansal Rajni

2014-04-01

Full Text Available We study the dependence of collective transverse flow and its disappearance on initialization effects via the nuclear radius within the framework of the Isospin-dependent Quantum Molecular Dynamics (IQMD model. We calculate the balance energy using different parametrizations of the radius available in the literature for the reaction of 12C+12C to explain its measured balance energy. A mass-dependent analysis of the balance energy through out the periodic table is also carried out by changing the default liquid drop IQMD radius.

Initialization effects via the nuclear radius on transverse in-plane flow and its disappearance

International Nuclear Information System (INIS)

Bansal, Rajni; Gautam, Sakshi

2014-01-01

We study the dependence of collective transverse flow and its disappearance on initialization effects via the nuclear radius within the framework of the Isospin-dependent Quantum Molecular Dynamics (IQMD) model. We calculate the balance energy using different parametrizations of the radius available in the literature for the reaction of 12 C + 12 C to explain its measured balance energy. A mass-dependent analysis of the balance energy through out the periodic table is also carried out by changing the default liquid drop IQMD radius. (author)

Langerhans cell sarcoma following marginal zone lymphoma: expanding the knowledge on mature B cell plasticity.

Science.gov (United States)

Ambrosio, Maria Raffaella; De Falco, Giulia; Rocca, Bruno Jim; Barone, Aurora; Amato, Teresa; Bellan, Cristiana; Lazzi, Stefano; Leoncini, Lorenzo

2015-10-01

The concept of unidirectional differentiation of the haematopoietic stem cell has been challenged after recent findings that human B cell progenitors and even mature B cells can be reprogrammed into histiocytic/dendritic cells by altering expression of lineage-associated transcription factors. The conversion of mature B cell lymphomas to Langerhans cell neoplasms is not well documented. Three previous reports have described clonally related follicular lymphoma and Langerhans cell tumours, whereas no case has been published of clonally related marginal zone lymphoma and Langerhans cell sarcoma. We describe the case of a 77-year-old patient who developed a Langerhans cell sarcoma and 6 years later a nodal marginal zone lymphoma. Mutation status examination showed 100 % gene identity to the germline sequence, suggesting direct trans-differentiation or dedifferentiation of the nodal marginal zone lymphoma to the Langerhans cell sarcoma rather than a common progenitor. We found inactivation of paired box 5 (PAX-5) in the lymphoma cells by methylation, along with duplication of part of the long arm of chromosomes 16 and 17 in the sarcoma cells. The absence of PAX-5 could have triggered B cells to differentiate into macrophages and dendritic cells. On the other hand, chromosomal imbalances might have activated genes involved in myeloid lineage maturation, transcription activation and oncogenesis. We hypothesize that this occurred because of previous therapies for nodal marginal zone lymphoma. Better understanding of this phenomenon may help in unravelling the molecular interplay between transcription factors during haematopoietic lineage commitment and may expand the spectrum of clonally related mature B cell neoplasms and Langerhans cell tumours.

Is the proton radius puzzle evidence of extra dimensions?

Energy Technology Data Exchange (ETDEWEB)

Dahia, F.; Lemos, A.S. [Universidade Federal da Paraiba, Department of Physics, Joao Pessoa, PB (Brazil)

2016-08-15

The proton charge radius inferred from muonic hydrogen spectroscopy is not compatible with the previous value given by CODATA-2010, which, on its turn, essentially relies on measurements of the electron-proton interaction. The proton's new size was extracted from the 2S-2P Lamb shift in the muonic hydrogen, which showed an energy excess of 0.3 meV in comparison to the theoretical prediction, evaluated with the CODATA radius. Higher-dimensional gravity is a candidate to explain this discrepancy, since the muon-proton gravitational interaction is stronger than the electron-proton interaction and, in the context of braneworld models, the gravitational potential can be hugely amplified in short distances when compared to the Newtonian potential. Motivated by these ideas, we study a muonic hydrogen confined in a thick brane. We show that the muon-proton gravitational interaction modified by extra dimensions can provide the additional separation of 0.3 meV between the 2S and 2P states. In this scenario, the gravitational energy depends on the higher-dimensional Planck mass and indirectly on the brane thickness. Studying the behavior of the gravitational energy with respect to the brane thickness in a realistic range, we find constraints for the fundamental Planck mass that solve the proton radius puzzle and are consistent with previous experimental bounds. (orig.)

Space Inside a Liquid Sphere Transforms into De Sitter Space by Hilbert Radius

Science.gov (United States)

Rabounski, Dmitri; Borissova, Larissa

2010-04-01

Consider space inside a sphere of incompressible liquid, and space surrounding a mass-point. Metrics of the spaces were deduced in 1916 by Karl Schwarzschild. 1) Our calculation shows that a liquid sphere can be in the state of gravitational collapse (g00 = 0) only if its mass and radius are close to those of the Universe (M = 8.7x10^55 g, a = 1.3x10^28 cm). However if the same mass is presented as a mass-point, the radius of collapse rg (Hilbert radius) is many orders lesser: g00 = 0 realizes in a mass-point's space by other conditions. 2) We considered a liquid sphere whose radius meets, formally, the Hilbert radius of a mass-point bearing the same mass: a = rg, however the liquid sphere is not a collapser (see above). We show that in this case the metric of the liquid sphere's internal space can be represented as de Sitter's space metric, wherein λ = 3/a^2 > 0: physical vacuum (due to the λ-term) is the same as the field of an ideal liquid where ρ0 0 (the mirror world liquid). The gravitational redshift inside the sphere is produced by the non-Newtonian force of repulsion (which is due to the λ-term, λ = 3/a^2 > 0); it is also calculated.

Frictional coefficient depending on active friction radius with BPV ...

African Journals Online (AJOL)

Frictional coefficient depending on active friction radius with BPV and BTV in automobile disc braking system. ... International Journal of Engineering, Science and Technology. Journal Home · ABOUT ... AJOL African Journals Online. HOW TO ...

Fractures of the distal radius in children: A retrospective evaluation

Directory of Open Access Journals (Sweden)

Selma Yazıcı

2012-06-01

Full Text Available Objectives: This study designed to evaluate the resultsof treatment, closed reduction and percutaneous wires, ofthe distal radius fractures in children.Materials and methods: A retrospective analysis wascarried out in children aged between 5-15 years who presentedwith a displaced fracture of the distal radius to ourhospital. They were initially treated with closed reductionand cast immobilization. If the fractures redisplaced treatedby percutaneous Kirschner (K- wire with scope undera general anaesthesia.Results: Totally 104 patients, who have distal radius fractureswere treated by closed reduction and immobilizationin a plaster cast. 13 patient who have distal radiusfractures were treated by closed reduction under generalanaesthesia and fixed by percutaneous Kirschner (K-wire. Patients with impaired the alignment of the fracturein late period were usually completely displaced fractures.(n=5, 4,3%, in early period, completely displaced fractures(n=5, 4,3% are superior to partial displaced fractures(n=2, 1,7%.Conclusion: In our study, when children with distal radiusfracture first come, they were treated by closed reductionand immobilization in a plaster cast. We thought that inredisplaced fractures patients were suitable for the closedreduction with percutaneous wire treatment.

Characterizing SL2S galaxy groups using the Einstein radius

DEFF Research Database (Denmark)

Verdugo, T.; Motta, V.; Foex, G.

2014-01-01

Aims. We aim to study the reliability of RA (the distance from the arcs to the center of the lens) as a measure of the Einstein radius in galaxy groups. In addition, we want to analyze the possibility of using RA as a proxy to characterize some properties of galaxy groups, such as luminosity (L......) and richness (N). Methods. We analyzed the Einstein radius, θE, in our sample of Strong Lensing Legacy Survey (SL2S) galaxy groups, and compared it with RA, using three different approaches: 1) the velocity dispersion obtained from weak lensing assuming a singular isothermal sphere profile (θE,I); 2) a strong.......7 ± 0.2)RA, θE,II = (0.4 ± 1.5) + (1.1 ± 0.4)RA, and θE,III = (0.4 ± 1.5) + (0.9 ± 0.3)RA for each method respectively. We found weak evidence of anti-correlation between RA and z, with Log RA = (0.58 ± 0.06) − (0.04 ± 0.1)z, suggesting a possible evolution of the Einstein radius with z, as reported...

Plastic value chains

DEFF Research Database (Denmark)

Baxter, John; Wahlstrom, Margareta; Zu Castell-Rüdenhausen, Malin

2014-01-01

Optimizing plastic value chains is regarded as an important measure in order to increase recycling of plastics in an efficient way. This can also lead to improved awareness of the hazardous substances contained in plastic waste, and how to avoid that these substances are recycled. As an example......, plastics from WEEE is chosen as a Nordic case study. The project aims to propose a number of improvements for this value chain together with representatives from Nordic stakeholders. Based on the experiences made, a guide for other plastic value chains shall be developed....

Hydroforming Process for an Ultrasmall Bending Radius Elbow

Directory of Open Access Journals (Sweden)

Shangwen Ruan

2018-01-01

Full Text Available Bent pipes are widely used in automotive, aviation, and aerospace industries for delivering fluids. Parts having small relative bending radiuses are called elbows. However, fabricating a thin-walled elbow part using the simple bending process poses many challenges. One possible way to manufacture elbows is with the stamping-welding process. The major drawbacks of this method include the decline in sealing performance and the addition in weight attributed to the lap welding process. Tube hydroforming (THF is considered as a feasible solution to these problems. However, the forming process could be quite complex, and multistep forming is necessary. This study investigates the effects of preliminary processes on elbow forming such as bending, partition forming, and heat treatment and presents a high-performance optimized process design to achieve an ultrasmall radius elbow. The effects of multistep forming on the thickness distribution and the heat treatment on the microstructure have been evaluated. The results obtained from simulations show a reasonable agreement with those from the experiments.

Nuclear charge radius of {sup 11}Li

Energy Technology Data Exchange (ETDEWEB)

Sanchez, Rodolfo, E-mail: R.Sanchez@GSI.de; Noertershaeuser, Wilfried [Gesellschaft fuer Schwerionenforschung (Germany); Dax, Andreas [CERN(Switzerland); Ewald, Guido; Goette, Stefan; Kirchner, Reinhard; Kluge, H.-Juergen; Kuehl, Thomas [Gesellschaft fuer Schwerionenforschung (Germany); Wojtaszek, Agnieszka [Swietokrzyska Academy, Institute of Physics (Poland); Bushaw, Bruce A. [Pacific Northwest National Laboratory (United States); Drake, Gordon W. F. [University of Windsor, Department of Physics (Canada); Yan Zongchao [University of New Brunswick, Department of Physics (Canada); Zimmermann, Claus [Physikalisches Institut, Eberhard Karls Universitaet Tuebingen (Germany); Albers, Daniel; Behr, John; Bricault, Pierre; Dilling, Jens; Dombsky, Marik; Lassen, Jens; Phil Levy, C. D. [Tri-University Meson Facility (Canada)

2006-07-15

We have determined the nuclear charge radius of {sup 11}Li by high-precision laser spectroscopy. The experiment was performed at the TRIUMF-ISAC facility where the {sup 7}Li-{sup 11}Li isotope shift (IS) was measured in the 2s{yields}3s electronic transition using Doppler-free two-photon spectroscopy with a relative accuracy better than 10{sup -5}. The accuracy for the IS of the other lithium isotopes was also improved. IS's are mainly caused by differences in nuclear mass, but changes in proton distribution also give small contributions. Comparing experimentally measured IS with advanced atomic calculation of purely mass-based shifts, including QED and relativistic effects, allows derivation of the nuclear charge radii. The radii are found to decrease monotonically from {sup 6}Li to {sup 9}Li, and then increase with {sup 11}Li about 11% larger than {sup 9}Li. These results are a benchmark for the open question as to whether nuclear core excitation by halo neutrons is necessary to explain the large nuclear matter radius of {sup 11}Li; thus, the results are compared with a number of nuclear structure models.

Our plastic age.

Science.gov (United States)

Thompson, Richard C; Swan, Shanna H; Moore, Charles J; vom Saal, Frederick S

2009-07-27

Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste plastic, the effects of plastic debris on wildlife and concerns for human health that arise from the production, usage and disposal of plastics. Finally, we consider some possible solutions to these problems together with the research and policy priorities necessary for their implementation.

Our plastic age

Science.gov (United States)

Thompson, Richard C.; Swan, Shanna H.; Moore, Charles J.; vom Saal, Frederick S.

2009-01-01

Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste plastic, the effects of plastic debris on wildlife and concerns for human health that arise from the production, usage and disposal of plastics. Finally, we consider some possible solutions to these problems together with the research and policy priorities necessary for their implementation. PMID:19528049

Investigation of the TEC Changes in the vicinity of the Earthquake Preparation Zone

Science.gov (United States)

Ulukavak, Mustafa; Yalcinkaya, Mualla

2016-04-01

Recently, investigation of the anomalies in the ionosphere before the earthquake has taken too much attention. The Total Electron Content (TEC) data has been used to monitor the changes in the ionosphere. Hence, researchers use the TEC changes before the strong earthquakes to monitor the anomalies in the ionosphere. In this study, the GPS-TEC variations, obtained from the GNSS stations in the vicinity of the earthquake preparation zone, was investigated. Nidra earthquake (M6.5), which was occurred on the north-west of Greece on November 17th, 2015 (38.755°N, 20.552°E), was selected for this study. First, the equation proposed by Dobrovolsky et al. (1979) was used to calculate the radius of the earthquake preparation zone. International GNSS Service (IGS) stations in the region were classified with respect to the radius of the earthquake preparation zone. The observation data of each station was obtained from the Crustal Dynamics Data and Information System (CDDIS) archive to estimate GPS-TEC variations between 16 October 2015 and 16 December 2015. Global Ionosphere Maps (GIM) products, obtained from the IGS, was used to check the robustness of the GPS-TEC variations. Possible anomalies were analyzed for each GNSS station by using the 15-day moving median method. In order to analyze these pre-earthquake ionospheric anomalies, we investigated three indices (Kp, F10.7 and Dst) related to the space weather conditions between 16 October 2015 and 16 December 2015. Solar and geomagnetic indices were obtained from The Oceanic and Atmospheric Administration (NOAA), The Canadian Space Weather Forecast Centre (CSWFC), and the Data Analysis Center for Geomagnetism and Space Magnetism Graduate School of Science, Kyoto University (WDC). This study aims at investigating the possible effects of the earthquake on the TEC variations.

The radius of RX Eridani

International Nuclear Information System (INIS)

Woolley, R.; Dean, J.

1976-01-01

Photoelectric observations of the light curves of RX Eri obtained in B, V and I, and radial velocity determinations, are combined to determine the radius by a method originally proposed by van Hoof which avoids matching colours in the rising and falling branches of the light curve and concentrates on the falling branch. The results agree well with those from other stars determined by the normal Baade-Wesselink method, but the method is easier to apply if the colour curve is flat in the falling branch. The parameters found for the star are r 0 = 5.5 Sun, mass = 0.45 Sun, and Msub(v) = + 0sup(m).54. (author)

On finite larmor radius stabilization of Z-pinches

International Nuclear Information System (INIS)

Hellsten, T.

1982-12-01

Finite Larmor radius stabilization of Z-pinches is discussed. Stability criteria can be derived for a class of equilibria having constant mass and current density. The internal modes can be stabilized provided the line density not exceed a critical value of the order of 10 18 ions/m. (Author)

Impact of Bio-Based Plastics on Current Recycling of Plastics

Directory of Open Access Journals (Sweden)

Luc Alaerts

2018-05-01

Full Text Available Bio-based plastics are increasingly appearing in a range of consumption products, and after use they often end up in technical recycling chains. Bio-based plastics are different from fossil-based ones and could disturb the current recycling of plastics and hence inhibit the closure of plastic cycles, which is undesirable given the current focus on a transition towards a circular economy. In this paper, this risk has been assessed via three elaborated case studies using data and information retrieved through an extended literature search. No overall risks were revealed for bio-based plastics as a group; rather, every bio-based plastic is to be considered as a potential separate source of contamination in current recycling practices. For PLA (polylactic acid, a severe incompatibility with PET (polyethylene terephthalate recycling is known; hence, future risks are assessed by measuring amounts of PLA ending up in PET waste streams. For PHA (polyhydroxy alkanoate there is no risk currently, but it will be crucial to monitor future application development. For PEF (polyethylene furanoate, a particular approach for contamination-related issues has been included in the upcoming market introduction. With respect to developing policy, it is important that any introduction of novel plastics is well guided from a system perspective and with a particular eye on incompatibilities with current and upcoming practices in the recycling of plastics.

Simultaneous Constraints on the Mass and Radius of Aql X–1 from Quiescence and X-Ray Burst Observations

Energy Technology Data Exchange (ETDEWEB)

Li, Zhaosheng [Department of Physics, Xiangtan University, Xiangtan, 411105 (China); Falanga, Maurizio [International Space Science Institute, Hallerstrasse 6, 3012 Bern (Switzerland); Chen, Li [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Qu, Jinlu [Laboratory for Particle Astrophysics, Institute of High Energy Physics, CAS, Beijing 100049 (China); Xu, Renxin, E-mail: lizhaosheng@xtu.edu.cn [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

2017-08-10

The measurement of neutron star mass and radius is one of the most direct ways to distinguish between various dense matter equations of state. The mass and radius of accreting neutron stars hosted in low-mass X-ray binaries can be constrained by several methods, including photospheric radius expansion from type I X-ray bursts and from quiescent spectra. In this paper, we apply for the first time these two methods simultaneously to constrain the mass and radius of Aql X–1. The quiescent spectra from Chandra and XMM-Newton , and photospheric radius expansion bursts from RXTE are used. The determination of the mass and radius of Aql X–1 is also used to verify the consistency between the two methods and to narrow down the uncertainties of the neutron star mass and radius. It is found that the distance to Aql X–1 should be in the range of 4.0–5.75 kpc, based on the overlapping confidence regions between photospheric radius expansion burst and quiescent spectra methods. In addition, we show that the mass and radius determined for the compact star in Aql X–1 are compatible with strange star equations of state and conventional neutron star models.

Elastic-plastic analysis of tube expansion in tubesheets

International Nuclear Information System (INIS)

Kasraie, B.; O'Donnell, W.J.; Porowski, J.S.; Selz, A.

1983-01-01

Conditions for expansion of tubes in tubesheets are often determined by the test. The tightness of the joint and pull out force are used as criteria for evaluation of the results. For closely spaced tubes, it is also necessary to control development of the plastic regions in the ligaments surrounding the tube being expanded. High local strains may occur and excessive distortion may result if the expansion of the tube is continued beyond the admissible limits. Elastic-plastic finite element analyses are performed herein in order to establish conditions for rolling of the tubes in tubesheets of low ligament efficiency. Such penetration patterns are often required in the design of tubular reactors for catalytic processes. The model considered includes individual tube expansion in tubesheets with triangular penetration patterns. The effect of prior expansion of the neighboring tubes is also evaluated. Gap elements are used to model the initial clearance of the tube in the hole. Development of the plastic zones and distortion of the ligaments is monitored during radial expansion of the tube diameter. The residual stresses between the tube and the hole surface and the history of gap closing after removal of the expansion tool are determined. The effect of axial extension of the tube on the tube thinning is determined. Tube thinning is often used as a measure of tube expansion in manufacturing processes. For the analyzed ligament efficiency, reliable joints are obtained for a thinning range within 2% to 3%

Determination of bone mineral density at distal radius measured by single photon absorptiometry

International Nuclear Information System (INIS)

Tomomitsu, Tatsushi; Yanagimoto, Shinichi; Hitomi, Go; Murakami, Akihiko; Suemori, Shinji; Yokobayashi, Tsuneo; Ishii, Koshi; Hiji, Hiroo

1988-01-01

We have discussed the index of the bone mineral density (BMD) at the distal radius measured by single photon absorptiometry. Initially, the shape at the distal radius was evaluated using an X-ray photogram of the forearm and a calculation formula of the cross-sectional area at the distal radius was performed using an X-CT photogram of the forearm. A new index for the bone mineral density (modified BMD, mBMD), bone mineral content/cross-sectional area, at the distal radius was obtained for 154 young normal subjects (20 ∼ 44 yrs.). No significant differences in the mBMD values between young normal males and females, except for the group 20 ∼ 24 year-old group, were observed. Furthermore, a significantly decreased in the mBMD values with aging was observed in females between the ages of 20 ∼ 24 and 40 ∼ 44. However, no significant changes in the mBMD values were recognized in the men. Thus, it was shown that the new BMD index, mBMD, was useful for evaluating the changes of the bone mass. (author)

Plastic condoms.

Science.gov (United States)

1968-01-01

Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly

Biodegradability of plastics.

Science.gov (United States)

Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

2009-08-26

Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

An Adaption Broadcast Radius-Based Code Dissemination Scheme for Low Energy Wireless Sensor Networks.

Science.gov (United States)

Yu, Shidi; Liu, Xiao; Liu, Anfeng; Xiong, Naixue; Cai, Zhiping; Wang, Tian

2018-05-10

Due to the Software Defined Network (SDN) technology, Wireless Sensor Networks (WSNs) are getting wider application prospects for sensor nodes that can get new functions after updating program codes. The issue of disseminating program codes to every node in the network with minimum delay and energy consumption have been formulated and investigated in the literature. The minimum-transmission broadcast (MTB) problem, which aims to reduce broadcast redundancy, has been well studied in WSNs where the broadcast radius is assumed to be fixed in the whole network. In this paper, an Adaption Broadcast Radius-based Code Dissemination (ABRCD) scheme is proposed to reduce delay and improve energy efficiency in duty cycle-based WSNs. In the ABCRD scheme, a larger broadcast radius is set in areas with more energy left, generating more optimized performance than previous schemes. Thus: (1) with a larger broadcast radius, program codes can reach the edge of network from the source in fewer hops, decreasing the number of broadcasts and at the same time, delay. (2) As the ABRCD scheme adopts a larger broadcast radius for some nodes, program codes can be transmitted to more nodes in one broadcast transmission, diminishing the number of broadcasts. (3) The larger radius in the ABRCD scheme causes more energy consumption of some transmitting nodes, but radius enlarging is only conducted in areas with an energy surplus, and energy consumption in the hot-spots can be reduced instead due to some nodes transmitting data directly to sink without forwarding by nodes in the original hot-spot, thus energy consumption can almost reach a balance and network lifetime can be prolonged. The proposed ABRCD scheme first assigns a broadcast radius, which doesn’t affect the network lifetime, to nodes having different distance to the code source, then provides an algorithm to construct a broadcast backbone. In the end, a comprehensive performance analysis and simulation result shows that the proposed

An Adaption Broadcast Radius-Based Code Dissemination Scheme for Low Energy Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Shidi Yu

2018-05-01

Full Text Available Due to the Software Defined Network (SDN technology, Wireless Sensor Networks (WSNs are getting wider application prospects for sensor nodes that can get new functions after updating program codes. The issue of disseminating program codes to every node in the network with minimum delay and energy consumption have been formulated and investigated in the literature. The minimum-transmission broadcast (MTB problem, which aims to reduce broadcast redundancy, has been well studied in WSNs where the broadcast radius is assumed to be fixed in the whole network. In this paper, an Adaption Broadcast Radius-based Code Dissemination (ABRCD scheme is proposed to reduce delay and improve energy efficiency in duty cycle-based WSNs. In the ABCRD scheme, a larger broadcast radius is set in areas with more energy left, generating more optimized performance than previous schemes. Thus: (1 with a larger broadcast radius, program codes can reach the edge of network from the source in fewer hops, decreasing the number of broadcasts and at the same time, delay. (2 As the ABRCD scheme adopts a larger broadcast radius for some nodes, program codes can be transmitted to more nodes in one broadcast transmission, diminishing the number of broadcasts. (3 The larger radius in the ABRCD scheme causes more energy consumption of some transmitting nodes, but radius enlarging is only conducted in areas with an energy surplus, and energy consumption in the hot-spots can be reduced instead due to some nodes transmitting data directly to sink without forwarding by nodes in the original hot-spot, thus energy consumption can almost reach a balance and network lifetime can be prolonged. The proposed ABRCD scheme first assigns a broadcast radius, which doesn’t affect the network lifetime, to nodes having different distance to the code source, then provides an algorithm to construct a broadcast backbone. In the end, a comprehensive performance analysis and simulation result shows that

[Distal radius fractures--retrospective quality control after conservative and operative therapy].

Science.gov (United States)

Sommer, C; Brendebach, L; Meier, R; Leutenegger, A

2001-01-01

The distal radius fracture is the most frequent fracture in the adult patient. The wide spectrum of different types of fracture and the coexisting factors make the choice for the optimal treatment difficult. As an interne quality control we retrospectively evaluated all patients with distal radius fractures treated in 1995 at our institution. The study included 69 adult patients with 71 distal radius fractures. After on average 26 months 58 patients with 59 fractures were clinically and radiologically evaluated. The patients were asked to give supplementary information about their follow-up treatment as well as any remaining physical difficulties and limitations in the daily life. All x-rays of the broken radius were carefully analysed and compared with the opposite side. The final results were evaluated according to the "Demerit Point System". Patients were treated with five different therapeutical methods. 76.3% of the patients showed a very good/good final result. In 56.7% of the cases secondary fracture dislocation occurred; the dislocation-rate of fractures treated with percutaneous k-wires was 93.3%! A clear correlation between secondary displacement and final results was found. A main factor for an optimal outcome is the anatomic restoration of length and axis of the distal radius as well as of joint congruency, also moderate angular deformities are well tolerated. Our collective showed an unexpected high rate of secondary displacement, especially in the k-wire group. The reasons for this unsatisfactory event are manifold: too optimistic indication, insufficient follow-up examination in the first four to six weeks, inconsequent change to a more stable fixation method in case of a secondary dislocation. The results of this retrospective evaluation had a major impact on our concept of treatment. The dorso-radial double-plate technique combined with bone graft will be more used in the future especially in younger patients. The new standardised concept is the

Full title: Biomechanical comparison between stainless steel, titanium and carbon-fiber reinforced polyetheretherketone volar locking plates for distal radius fractures.

Science.gov (United States)

Mugnai, Raffaele; Tarallo, Luigi; Capra, Francesco; Catani, Fabio

2018-05-25

As the popularity of volar locked plate fixation for distal radius fractures has increased, so have the number and variety of implants, including variations in plate design, the size and angle of the screws, the locking screw mechanism, and the material of the plates. carbon-fiber reinforced polyetheretherketone (CFR-PEEK) plate features similar biomechanical properties to metallic plates, representing, therefore, an optimal alternative for the treatment of distal radius fractures. three different materials-composed plates were evaluated: stainless steel volar lateral column (Zimmer); titanium DVR (Hand Innovations); CFR-PEEK DiPHOS-RM (Lima Corporate). Six plates for each type were implanted in sawbones and an extra-articular rectangular osteotomy was created. Three plates for each material were tested for load to failure and bending stiffness in axial compression. Moreover, 3 constructs for each plate were evaluated after dynamically loading for 6000 cycles of fatigue. the mean bending stiffness pre-fatigue was significantly higher for the stainless steel plate. The titanium plate yielded the higher load to failure both pre and post fatigue. After cyclic loading, the bending stiffness increased by a mean of 24% for the stainless steel plate; 33% for the titanium; and 17% for the CFR-PEEK plate. The mean load to failure post-fatigue increased by a mean of 10% for the stainless steel and 14% for CFR-PEEK plates, whereas it decreased (-16%) for the titanium plate. Statistical analysis between groups reported significant values (p plastic deformation, and lower load to failure. N/A. Copyright © 2018. Published by Elsevier Masson SAS.

Characterization of plastic blends made from mixed plastics waste of different sources.

Science.gov (United States)

Turku, Irina; Kärki, Timo; Rinne, Kimmo; Puurtinen, Ari

2017-02-01

This paper studies the recyclability of construction and household plastic waste collected from local landfills. Samples were processed from mixed plastic waste by injection moulding. In addition, blends of pure plastics, polypropylene and polyethylene were processed as a reference set. Reference samples with known plastic ratio were used as the calibration set for quantitative analysis of plastic fractions in recycled blends. The samples were tested for the tensile properties; scanning electron microscope-energy-dispersive X-ray spectroscopy was used for elemental analysis of the blend surfaces and Fourier transform infrared (FTIR) analysis was used for the quantification of plastics contents.

Multilevel modeling of micromechanics and phase formation for microstructural evolution of magnetic zones

International Nuclear Information System (INIS)

Suwa, Yoshihiro; Aizawa, Tatsuhiko; Takaya, Shigeru; Nagae, Yuji; Aoto, Kazumi

2005-03-01

The present research aims at a proposal of theoretical treatise to describe the local phase transformation from austenite to ferrite in the stainless steels under hot cyclic fatigue conditions. In experiments, this local phase transformation is detected as a magnetized region in the non-magnetic matrix after low-cycle fatigue test at the elevated temperature. The theoretical frame proposed here is composed of two methodologies. In the first approach, microstructure evolution with γ → α transformation is described by the phase field method. In the second approach, micromechanical method on the basis of the unit cell modeling is proposed to develop a new micromechanical analysis. The details of two approached are summarized in the following. (1) Phase formation simulation by the phase field method. Most of reports have started that γ-α phase transformation as a creep damage is induced by dechromization, which comes from carbide precipitation around grain boundaries. A new theoretical treatise is proposed for simulating this γ → α transformation in Fe-Cr-Ni system. Stabilities of both phases are investigated for various chemical compositions. Furthermore, in order to investigate dechromization phenomena in Fe-Cr-Ni-C system, a new theoretical frame is also proposed to handle an interstitial element in phase field method. (2) Low cycle fatigue elasto-plastic analysis by the unit-cell modeling. In experiments, the magnetized zones are generated to distribute at the vicinity of the hard, delta-phase inclusion in the austenitic matrix. The cumulative plastic region advances in the surroundings of this hard inclusion with increasing the number of cycles in the controlled strain range. This predicted profile of cumulative plastic regions corresponds to the experimentally measured, magnetized zones. In addition, the effect of geometric configuration of this inclusion on the plastic region evolution has close relationship of creep damage advancement in experiments

The Prevalence of Cosmetic Facial Plastic Procedures among Facial Plastic Surgeons.

Science.gov (United States)

Moayer, Roxana; Sand, Jordan P; Han, Albert; Nabili, Vishad; Keller, Gregory S

2018-04-01

This is the first study to report on the prevalence of cosmetic facial plastic surgery use among facial plastic surgeons. The aim of this study is to determine the frequency with which facial plastic surgeons have cosmetic procedures themselves. A secondary aim is to determine whether trends in usage of cosmetic facial procedures among facial plastic surgeons are similar to that of nonsurgeons. The study design was an anonymous, five-question, Internet survey distributed via email set in a single academic institution. Board-certified members of the American Academy of Facial Plastic and Reconstructive Surgery (AAFPRS) were included in this study. Self-reported history of cosmetic facial plastic surgery or minimally invasive procedures were recorded. The survey also queried participants for demographic data. A total of 216 members of the AAFPRS responded to the questionnaire. Ninety percent of respondents were male ( n  = 192) and 10.3% were female ( n  = 22). Thirty-three percent of respondents were aged 31 to 40 years ( n  = 70), 25% were aged 41 to 50 years ( n  = 53), 21.4% were aged 51 to 60 years ( n  = 46), and 20.5% were older than 60 years ( n  = 44). Thirty-six percent of respondents had a surgical cosmetic facial procedure and 75% has at least one minimally invasive cosmetic facial procedure. Facial plastic surgeons are frequent users of cosmetic facial plastic surgery. This finding may be due to access, knowledge base, values, or attitudes. By better understanding surgeon attitudes toward facial plastic surgery, we can improve communication with patients and delivery of care. This study is a first step in understanding use of facial plastic procedures among facial plastic surgeons. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Recycling of plastic waste: Presence of phthalates in plastics from households and industry.

Science.gov (United States)

Pivnenko, K; Eriksen, M K; Martín-Fernández, J A; Eriksson, E; Astrup, T F

2016-08-01

Plastics recycling has the potential to substitute virgin plastics partially as a source of raw materials in plastic product manufacturing. Plastic as a material may contain a variety of chemicals, some potentially hazardous. Phthalates, for instance, are a group of chemicals produced in large volumes and are commonly used as plasticisers in plastics manufacturing. Potential impacts on human health require restricted use in selected applications and a need for the closer monitoring of potential sources of human exposure. Although the presence of phthalates in a variety of plastics has been recognised, the influence of plastic recycling on phthalate content has been hypothesised but not well documented. In the present work we analysed selected phthalates (DMP, DEP, DPP, DiBP, DBP, BBzP, DEHP, DCHP and DnOP) in samples of waste plastics as well as recycled and virgin plastics. DBP, DiBP and DEHP had the highest frequency of detection in the samples analysed, with 360μg/g, 460μg/g and 2700μg/g as the maximum measured concentrations, respectively. Among other, statistical analysis of the analytical results suggested that phthalates were potentially added in the later stages of plastic product manufacturing (labelling, gluing, etc.) and were not removed following recycling of household waste plastics. Furthermore, DEHP was identified as a potential indicator for phthalate contamination of plastics. Close monitoring of plastics intended for phthalates-sensitive applications is recommended if recycled plastics are to be used as raw material in production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Appreciation of Triaxiality Influence in Plastic Deformation Accompanying Ductile Rupture

Science.gov (United States)

Coseru, Ancuta-Ioana; Zichil, Valentin; Lupascu, Stefan

2017-12-01

In this paper, the authors propose a studying method for the deformation that appears before crack of ductile materials using the Lode parameter determined by the numerical calculation applied on simple models, verified in previous studies. In order to highlight the influence of the Lode parameter, the tests were performed at simple but also at compound tests. The necessity of these studies lies in the fact that the acknowledged models (the use of the integral J, the critical stress intensity factor Kc or the CPCD method) do not fully explain the phenomenon of deformation before breaking the elasto-plastic materials. The tests were imagined under the form of sets. Each set of tests was performed on smooth specimens and on specimens with a notch radius of 0.5, 2, 4 and 10 mm. Also, each set of tests was performed for pure tensile and combined tensile-torque test.

Recycling of plastic waste: Presence of phthalates in plastics from households and industry

DEFF Research Database (Denmark)

Pivnenko, Kostyantyn; Eriksen, Marie Kampmann; Martín-Fernández, J. A.

2016-01-01

Plastics recycling has the potential to substitute virgin plastics partially as a source of raw materials in plastic product manufacturing. Plastic as a material may contain a variety of chemicals, some potentially hazardous. Phthalates, for instance, are a group of chemicals produced in large...... recognised, the influence of plastic recycling on phthalate content has been hypothesised but not well documented. In the present work we analysed selected phthalates (DMP, DEP, DPP, DiBP, DBP, BBzP, DEHP, DCHP and DnOP) in samples of waste plastics as well as recycled and virgin plastics. DBP, DiBP and DEHP...

Biodegradability of Plastics

Directory of Open Access Journals (Sweden)

Yutaka Tokiwa

2009-08-01

Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

Enhanced mechanical properties of single walled carbon nanotube-borosilicate glass composite due to cushioning effect and localized plastic flow

Directory of Open Access Journals (Sweden)

Sujan Ghosh

2011-12-01

Full Text Available A borosilicate glass composite has been fabricated incorporating Single Wall Carbon Nanotubes (SWCNT in the glass matrix by melt-quench technique. Hardness and the fracture toughness of the composite, were found to increase moderately with respect to the base glass. Interestingly one can observe accumulation of SWCNT bundles around the crack zone though no such accumulation was observed in the crack free indentation zone. The enhanced hardness of the composite was discussed by correlating the cushioning as well as toughening behavior of the agglomerated SWCNT bundles. On the other hand enhanced plastic flow was proposed to be the prime reason for the accumulation of SWCNT bundles around the crack, which increases the toughness of the composite by reducing the crack length. Moreover to ascertain the enhanced plasticity of the composite than that of the glass we calculated the recovery resistance of glass and the composite where recovery resistance of composite was found to be higher than that of the glass.

Evaluation of plastic collapse behavior for multiple cracked structures

International Nuclear Information System (INIS)

Moon, Seong In; Chang, Yoon Suk; Kim, Young Jin; Lee, Jin Ho; Song, Myung Ho; Choi, Young Hwan; Hwang, Seong Sik

2004-01-01

Until now, the 40% of wall thickness criterion, which is generally used for the plugging of steam generator tubes, has been applied only to a single cracked geometry. In the previous study by the authors, a total number of 9 local failure prediction models were introduced to estimate the coalescence load of two collinear through-wall cracks and, then, the reaction force model and plastic zone contact model were selected as the optimum ones. The objective of this study is to estimate the coalescence load of two collinear through-wall cracks in steam generator tube by using the optimum local failure prediction models. In order to investigate the applicability of the optimum local failure prediction models, a series of plastic collapse tests and corresponding finite element analyses for two collinear through-wall cracks in steam generator tube were carried out. Thereby, the applicability of the optimum local failure prediction models was verified and, finally, a coalescence evaluation diagram which can be used to determine whether the adjacent cracks detected by NDE coalesce or not has been developed

Mutagenic effects induced by accumulating rare earths nuclides with different ionic radius in fission fragments

International Nuclear Information System (INIS)

Zhu Shoupeng; Wang Liuyi; Cao Genfa; Sun Baofu

1991-05-01

The purpose of the present study was to ascertain the correlation between the different ionic radius of rare earths nuclides such as 170 Tm, 152 Eu, 147 Pm and its accumulation peculiarity as well as induction of mutagenic effect on bone marrow cells. The study showed that the accumulation peculiarity of rare earths nuclides will vary with the ionic radius. The results indicated that large ionic radius of 147 Pm was selectively localized in liver in early stage, while small ionic radius of 170 Tm and 152 Eu were deposited in bone predominantly. There was a positive relationship between the incidence of chromosome aberration rates and the absorption dose in skeleton by 170 Tm, 152 Eu, or 147 Pm. Studies indicated that the chromosome aberration rates were elevated when the absorption dose in skeleton was increased. Among the type of chromosome aberrations induced by rare earths nuclides with different ionic radius, chromatid breakage was predominant, accompanied with a few chromosome breakage and translocation. At the same time mitosis index of metaphase cells was depressed. Internal contamination of 170 Tm, 152 Eu, or 147 Pm can be induced by some aberrations in one cell. This phenomenon might be due in part to nonuniform irradiation of bone marrow cell with local deposition of these rare earths nuclides with different ionic radius

Elastic-plastic behaviour of thick-walled containers considering plastic compressibility

International Nuclear Information System (INIS)

Betten, J.; Frosch, H.G.

1983-01-01

In this paper the elastic-plastic behaviour of thick-walled pressure vessels with internal and external pressure is studied. To describe the mechanical behaviour of isotropic, plastic compressible materials we use a plastic potential which is a single-valued function of the principle stresses. For cylinders and spheres an analytic expression for the computation of stresses and residual stresses is specified. Afterwards the strains are calculated by using the finite difference method. Some examples will high-light the influence of the plastic compressibility on the behaviour of pressure vessels. (orig.) [de

Mechanisms of strain accommodation in plastically-deformed zircon under simple shear deformation conditions during amphibolite-facies metamorphism

Science.gov (United States)

Kovaleva, Elizaveta; Klötzli, Urs; Wheeler, John; Habler, Gerlinde

2018-02-01

This study documents the strain accommodation mechanisms in zircon under amphibolite-facies metamorphic conditions in simple shear. Microstructural data from undeformed, fractured and crystal-plastically deformed zircon crystals are described in the context of the host shear zone, and evaluated in the light of zircon elastic anisotropy. Our work challenges the existing model of zircon evolution and shows previously undescribed rheological characteristics for this important accessory mineral. Crystal-plastically deformed zircon grains have axis oriented parallel to the foliation plane, with the majority of deformed grains having axis parallel to the lineation. Zircon accommodates strain by a network of stepped low-angle boundaries, formed by switching between tilt dislocations with the slip systems {010} and {110} and rotation axis [001], twist dislocations with the rotation axis [001], and tilt dislocations with the slip system {001} and rotation axis [010]. The slip system {110} is newly described for zircon. Most misorientation axes in plastically-deformed zircon grains are parallel to the XY plane of the sample and have [001] crystallographic direction. Such behaviour of strained zircon lattice is caused by elastic anisotropy that has a direct geometric control on the rheology, deformation mechanisms and dominant slip systems in zircon. Young's modulus and P wave velocity have highest values parallel to zircon [001] axis, indicating that zircon is elastically strong along this direction. Poisson ratio and Shear modulus demonstrate that zircon is also most resistant to shearing along [001]. Thus, [001] axis is the most common rotation axis in zircon. The described zircon behaviour is important to take into account during structural and geochronological investigations of (poly)metamorphic terrains. Geometry of dislocations in zircon may help reconstructing the geometry of the host shear zone(s), large-scale stresses in the crust, and, possibly, the timing of

Sectio Aurea Conditions for Mityuk's Radius of Two-Connected Domains

Directory of Open Access Journals (Sweden)

A.V. Kazantsev

2017-03-01

Full Text Available Connection of an exterior inverse boundary value problem with the critical points of some surface is one of the central themes in the theory of exterior inverse boundary value problems for analytic functions. In the simply connected case, such a surface is defined by the inner mapping radius; in the multiply connected one, by the function Ω(w such that M(w = (2π–1ln Ω(w is Mityuk's version of a generalized reduced module. In the present paper, the relation between the curvature of the surface Ω = Ω(w with the Schwarzian derivatives of the mapping functions and with the Bergman kernel functions k0(w,ω and l0(w,ω is established for an arbitrary multiply connected domain. When passing to two-connected domains, due to the choice of the ring as a canonical domain, we construct the conditions for the critical points of Mityuk's radius to concentrate on the golden section circle of the ring. Finally, we show that the minimal collection of the critical points of the Mityuk radius in the two-connected case, consisting of one maximum and one saddle, is attained for the linear-fractional solution of the exterior inverse boundary value problem.

The mean free path of protons in nuclei and the nuclear radius

International Nuclear Information System (INIS)

Dymarz, R.; Kohmura, T.

1983-01-01

We determine the mean free path of protons in nuclei in the energy range 40-1000 MeV. We find that it is necessary to use in the calculation of the mean free path the nuclear radius R which reproduces the reaction and total cross sections consistently and that this radius leads to a rather small mean free path which is comparable with the value obtained in the microscopic calculation in the whole energy region. (orig.)

Accuracy of specimen-specific nonlinear finite element analysis for evaluation of distal radius strength in cadaver material.

Science.gov (United States)

Matsuura, Yusuke; Kuniyoshi, Kazuki; Suzuki, Takane; Ogawa, Yasufumi; Sukegawa, Koji; Rokkaku, Tomoyuki; Takahashi, Kazuhisa

2014-11-01

Distal radius fracture, which often occurs in the setting of osteoporosis, can lead to permanent deformity and disability. Great effort has been directed toward developing noninvasive methods for evaluating the distal radius strength, with the goal of assessing fracture risk. The aim of this study was to evaluate distal radius strength using a finite element model and to gauge the accuracy of finite element model measurement using cadaver material. Ten wrists were obtained from cadavers with a mean age of 89.5 years at death. CT images of each wrist in an extended position were obtained. CT-based finite element models were prepared with Mechanical Finder software. Fracture on the models was simulated by applying a mechanical load to the palm in a direction parallel to the forearm axis, after which the fracture load and the site at which the fracture began were identified. For comparison, the wrists were fractured using a universal testing machine and the fracture load and the site of fracture were identified. The fracture load was 970.9 N in the finite element model group and 990.0 N in the actual measurement group. The site of the initial fracture was extra-articular to the distal radius in both groups. The finite element model was predictive for distal radius fracture when compared to the actual measurement. In this study, a finite element model for evaluation of distal radius strength was validated and can be used to predict fracture risk. We conclude that a finite element model is useful for the evaluation of distal radius strength. Knowing distal radius strength might avoid distal radius fracture because appropriate antiosteoporotic treatment can be initiated.

Incorporation of ladle furnace slag in ceramic formulations: study of extrusion zones; Incorporacao da escoria do forno panela em formulacao ceramica: estudo das zonas de extrusao

Energy Technology Data Exchange (ETDEWEB)

Feitosa, E.F.; Santana, C.M.; Luna, D.S.; Santos, D.M.S.; Silva, G.S.; Noleto, L.T.; Almeida, N.C.; Rabelo, A.A.; Fagury Neto, E., E-mail: edna.fernandes48@gmail.com, E-mail: fagury@unifesspa.edu.br [Universidade Federal do Sul e Sudeste do Para (UNIFESSPA), Maraba, PA (Brazil). Instituto de Geociencias e Engenharias

2016-07-01

This study aimed to investigate the effect of incorporation of ladle furnace slag (LFS) in two clays with higher and lower plasticity, used for the manufacture of structural ceramics. The LFS from a local steel making plant was added to ceramic compositions in proportions of 8 %, 14 % and 16 %. The formulations were tested in appropriate equipment that measures the liquid limit and plastic limit. The property examined was the plasticity index, in order to make a study of the extrusion zones. Results showed that the addition of slag into clay mixtures alters the plasticity; however, the extrusion process was not hampered. (author)

The Assessment of Left Ventricular Time-Varying Radius Using Tissue Doppler Imaging

Directory of Open Access Journals (Sweden)

Fardin Mirbolouk

2012-03-01

Full Text Available Background: Left ventricular twist/torsion is believed to be a sensitive indicator of systolic and diastolic performance. To obtain circumferential rotation using tissue Doppler imaging, we need to estimate the time-varying radius of the left ventricle throughout the cardiac cycle to convert the tangential velocity into angular velocity. Objectives: The aim of this study was to investigate accuracy of measured LV radius using tissue Doppler imaging throughout the cardiac cycle compared to two-dimensional (2D imaging. Methods: A total of 35 subjects (47±12 years old underwent transthoracic echocardiographic standard examinations. Left ventricular radius during complete cardiac cycle measured using tissue Doppler and 2D-imaging at basal and apical short axis levels. For this reason, the 2D-images and velocity-time data derived and transferred to a personal computer for off-line analysis. 2D image frames analyzed via a program written in the MATLAB software. Velocity-time data from anteroseptal at basal level (or anterior wall at apical level and posterior walls transferred to a spreadsheet Excel program for the radius calculations. Linear correlation and Bland-Altman analysis were calculated to assess the relationships and agreements between the tissue Doppler and 2D-measured radii throughout the cardiac cycle. Results: There was significant correlation between tissue Doppler and 2D-measured radii and the Pearson correlation coefficients were 0.84 to 0.97 (P<0.05. Bland-Altman analysis by constructing the 95% limits of agreement showed that the good agreements existed between the two methods. Conclusion: It can be concluded from our experience that the tissue Doppler imaging can reasonably estimate radius of the left ventricle throughout the cardiac cycle.

Mechanically equivalent elastic-plastic deformations and the problem of plastic spin

Directory of Open Access Journals (Sweden)

Steigmann David J.

2011-01-01

Full Text Available The problem of plastic spin is phrased in terms of a notion of mechanical equivalence among local intermediate configurations of an elastic/ plastic crystalline solid. This idea is used to show that, without further qualification, the plastic spin may be suppressed at the constitutive level. However, the spin is closely tied to an underlying undistorted crystal lattice which, once specified, eliminates the freedom afforded by mechanical equivalence. As a practical matter a constitutive specification of plastic spin is therefore required. Suppression of plastic spin thus emerges as merely one such specification among many. Restrictions on these are derived in the case of rate-independent response.

The importance of Radio Quiet Zone (RQZ) for radio astronomy

Science.gov (United States)

Umar, Roslan; Abidin, Zamri Zainal; Ibrahim, Zainol Abidin

2013-05-01

Most of radio observatories are located in isolated areas. Since radio sources from the universe is very weak, astronomer need to avoid radio frequency interference (RFI) from active spectrum users and radio noise produced by human made (telecommunication, mobile phone, microwave user and many more. There are many observatories around the world are surrounded by a Radio Quiet Zone (RQZ), which is it was set up using public or state laws. A Radio Quiet Zone normally consists of two areas: an exclusive area in which totally radio emissions are forbidden, with restrictions for residents and business developments, and a larger (radius up to 100 km above) coordination area where the power of radio transmission limits to threshold levels. Geographical Information System (GIS) can be used as a powerful tool in mapping large areas with varying RQZ profiles. In this paper, we report the initial testing of the usage of this system in order to identify the areas were suitable for Radio Quiet Zone. Among the important parameters used to develop the database for our GIS are population density, information on TV and telecommunication (mobile phones) transmitters, road networks (highway), and contour shielding. We will also use other information gathered from on-site RFI level measurements on selected 'best' areas generated by the GIS. The intention is to find the best site for the purpose of establishing first radio quiet zones for radio telescope in Malaysia.

NEUTRON STAR MASS–RADIUS CONSTRAINTS USING EVOLUTIONARY OPTIMIZATION

Energy Technology Data Exchange (ETDEWEB)

Stevens, A. L.; Morsink, S. M. [Department of Physics, University of Alberta, 4-183 CCIS, Edmonton, AB, T6G 2E1 (Canada); Fiege, J. D. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Leahy, D. A. [Department of Physics, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4 (Canada)

2016-12-20

The equation of state of cold supra-nuclear-density matter, such as in neutron stars, is an open question in astrophysics. A promising method for constraining the neutron star equation of state is modeling pulse profiles of thermonuclear X-ray burst oscillations from hot spots on accreting neutron stars. The pulse profiles, constructed using spherical and oblate neutron star models, are comparable to what would be observed by a next-generation X-ray timing instrument like ASTROSAT , NICER , or a mission similar to LOFT . In this paper, we showcase the use of an evolutionary optimization algorithm to fit pulse profiles to determine the best-fit masses and radii. By fitting synthetic data, we assess how well the optimization algorithm can recover the input parameters. Multiple Poisson realizations of the synthetic pulse profiles, constructed with 1.6 million counts and no background, were fitted with the Ferret algorithm to analyze both statistical and degeneracy-related uncertainty and to explore how the goodness of fit depends on the input parameters. For the regions of parameter space sampled by our tests, the best-determined parameter is the projected velocity of the spot along the observer’s line of sight, with an accuracy of ≤3% compared to the true value and with ≤5% statistical uncertainty. The next best determined are the mass and radius; for a neutron star with a spin frequency of 600 Hz, the best-fit mass and radius are accurate to ≤5%, with respective uncertainties of ≤7% and ≤10%. The accuracy and precision depend on the observer inclination and spot colatitude, with values of ∼1% achievable in mass and radius if both the inclination and colatitude are ≳60°.

21 CFR 886.1450 - Corneal radius measuring device.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Corneal radius measuring device. 886.1450 Section 886.1450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... corneal size by superimposing the image of the cornea on a scale at the focal length of the lens of a...

Analysis of the radius and diameter protocols in terms of pricing telecommunication services

Directory of Open Access Journals (Sweden)

Vesna M. Radonjić

2013-06-01

Full Text Available Accounting of telecommunication services is closely related to the functions of authentication and authorization. These functions are usually considered together and implemented within the same server using a common protocol. The most renowned protocols for authentication, authorization and accounting are the RADIUS and Diameter protocols.   AAA functions and related protocols   In this chapter, the accounting management architecture developed by IETF is presented. It includes the interaction between network elements, accounting servers and billing and charging servers. Accounting data can be used for management, planning and charging users as well as other (specific purposes. Authentication is the process of confirming a user's digital identity, usually through some type of identifiers and related data. Authorization determines whether a particular entity is authorized to perform an activity.   Basic Functions of the RADIUS Protocol   The RADIUS architecture is based on a client-server model. It uses UDP on the transport layer. Transactions between the client and the server are authenticated, which is achieved by using a common secret key that is never sent through the network. Given the limited resources available to network devices, RADIUS facilitates and centralizes charging end users, provides some protection against active attacks by unauthorized users and it has great support from different network equipment vendors. Although RADIUS is a widely accepted protocol for the mechanisms of authentication, authorization and accounting, it has certain shortcomings that may be caused by the protocol itself or by its poor implementation.   Architecture and Operation of the Diameter Protocol   Diameter is a scalable protocol designed by the IETF working group in order to eliminate shortcomings and functional limitations of the RADIUS protocol and eventually to replace it in the near future. Most of the basic Diameter mechanisms and its

A Spitzer Infrared Radius for the Transiting Extrasolar Planet HD 209458 b

Science.gov (United States)

Richardson, L. Jeremy; Harrington, Joseph; Seager, Sara; Deming, Drake

2007-01-01

We have measured the infrared transit of the extrasolar planet HD 209458 b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24 micrometer array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10-second integrations) of the planetary system, recorded before, during, and after transit. We perform optimal photometry on the images and use the local zodiacal light as a short-term flux reference. At this long wavelength, the transit curve has a simple box-like shape, allowing robust solutions for the stellar and planetary radii independent of stellar limb darkening, which is negligible at 24 micrometers. We derive a stellar radius of R(sub *) = 1.06 plus or minus 0.07 solar radius, a planetary radius of R(sub p) = 1.26 plus or minus 0.08 R(sub J), and a stellar mass of 1.17 solar mass. Within the errors, our results agree with the measurements at visible wavelengths. The 24 micrometer radius of the planet therefore does not differ significantly compared to the visible result. We point out the potential for deriving extrasolar transiting planet radii to high accuracy using transit photometry at slightly shorter IR wavelengths where greater photometric precision is possible.

Plastics and health risks.

Science.gov (United States)

Halden, Rolf U

2010-01-01

By 2010, the worldwide annual production of plastics will surpass 300 million tons. Plastics are indispensable materials in modern society, and many products manufactured from plastics are a boon to public health (e.g., disposable syringes, intravenous bags). However, plastics also pose health risks. Of principal concern are endocrine-disrupting properties, as triggered for example by bisphenol A and di-(2-ethylhexyl) phthalate (DEHP). Opinions on the safety of plastics vary widely, and despite more than five decades of research, scientific consensus on product safety is still elusive. This literature review summarizes information from more than 120 peer-reviewed publications on health effects of plastics and plasticizers in lab animals and humans. It examines problematic exposures of susceptible populations and also briefly summarizes adverse environmental impacts from plastic pollution. Ongoing efforts to steer human society toward resource conservation and sustainable consumption are discussed, including the concept of the 5 Rs--i.e., reduce, reuse, recycle, rethink, restrain--for minimizing pre- and postnatal exposures to potentially harmful components of plastics.

Recycling of plastic waste: Presence of phthalates in plastics from households and industry

DEFF Research Database (Denmark)

Pivnenko, Kostyantyn; Eriksen, Marie Kampmann; Martín-Fernández, J. A.

2016-01-01

recognised, the influence of plastic recycling on phthalate content has been hypothesised but not well documented. In the present work we analysed selected phthalates (DMP, DEP, DPP, DiBP, DBP, BBzP, DEHP, DCHP and DnOP) in samples of waste plastics as well as recycled and virgin plastics. DBP, DiBP and DEHP...... product manufacturing (labelling, gluing, etc.) and were not removed following recycling of household waste plastics. Furthermore, DEHP was identified as a potential indicator for phthalate contamination of plastics. Close monitoring of plastics intended for phthalates-sensitive applications...

Cost Effective RADIUS Authentication for Wireless Clients

Directory of Open Access Journals (Sweden)

Alexandru ENACEANU

2010-12-01

Full Text Available Network administrators need to keep administrative user information for each network device, but network devices usually support only limited functions for user management. WLAN security is a modern problem that needs to be solved and it requires a lot of overhead especially when applied to corporate wireless networks. Administrators can set up a RADIUS server that uses an external database server to handle authentication, authorization, and accounting for network security issues.

Influence of radius of cylinder HTS bulk on guidance force in a maglev vehicle system

International Nuclear Information System (INIS)

Longcai, Zhang

2014-01-01

Highlights: • The guidance force was decayed by the application of the AC external magnetic field. • The guidance force was higher for the bulk with bigger radius. • The guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. - Abstract: Bulk superconductors had great potential for various engineering applications, especially in a high-temperature superconducting (HTS) maglev vehicle system. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFeB guideway used in the HTS maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we investigated the influence of the radius of the cylinder HTS bulk exposed to an AC magnetic field perturbation on the guidance force in the maglev vehicle system. From the results, it was found that the guidance force was stronger for the bulk with bigger radius and the guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. Therefore, in order to obtain higher guidance force in the maglev vehicle system, we could use the cylinder HTS bulks with the bigger radius

Influence of radius of cylinder HTS bulk on guidance force in a maglev vehicle system

Energy Technology Data Exchange (ETDEWEB)

Longcai, Zhang, E-mail: zhlcai2000@163.com

2014-07-15

Highlights: • The guidance force was decayed by the application of the AC external magnetic field. • The guidance force was higher for the bulk with bigger radius. • The guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. - Abstract: Bulk superconductors had great potential for various engineering applications, especially in a high-temperature superconducting (HTS) maglev vehicle system. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFeB guideway used in the HTS maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we investigated the influence of the radius of the cylinder HTS bulk exposed to an AC magnetic field perturbation on the guidance force in the maglev vehicle system. From the results, it was found that the guidance force was stronger for the bulk with bigger radius and the guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. Therefore, in order to obtain higher guidance force in the maglev vehicle system, we could use the cylinder HTS bulks with the bigger radius.

Effect of Process Parameters on the Total Heat Damaged Zone (HDZ) during Micro-EDM of Plastic Mold Steel 1.2738

DEFF Research Database (Denmark)

Puthumana, Govindan

2016-01-01

In micro electrical discharge machining, three subsurface layersare formed on the workpiece, they are;recast zone, heat affected zone and converted zone, primarily due to heating-quenching cycles. The HDZ inmicro-EDM is characterized by cracks and weakness in the grain boundary and thermal residu...

The Splashback Radius of Halos from Particle Dynamics. I. The SPARTA Algorithm

Science.gov (United States)

Diemer, Benedikt

2017-07-01

Motivated by the recent proposal of the splashback radius as a physical boundary of dark-matter halos, we present a parallel computer code for Subhalo and PARticle Trajectory Analysis (SPARTA). The code analyzes the orbits of all simulation particles in all host halos, billions of orbits in the case of typical cosmological N-body simulations. Within this general framework, we develop an algorithm that accurately extracts the location of the first apocenter of particles after infall into a halo, or splashback. We define the splashback radius of a halo as the smoothed average of the apocenter radii of individual particles. This definition allows us to reliably measure the splashback radii of 95% of host halos above a resolution limit of 1000 particles. We show that, on average, the splashback radius and mass are converged to better than 5% accuracy with respect to mass resolution, snapshot spacing, and all free parameters of the method.

Challenges in plastics recycling

DEFF Research Database (Denmark)

Pivnenko, Kostyantyn; Jakobsen, L. G.; Eriksen, Marie Kampmann

2015-01-01

Recycling of waste plastics still remains a challenging area in the waste management sector. The current and potential goals proposed on EU or regional levels are difficult to achieve, and even to partially fullfil them the improvements in collection and sorting should be considerable. A study...... was undertaken to investigate the factors affecting quality in plastics recycling. The preliminary results showed factors primarily influencing quality of plastics recycling to be polymer cross contamination, presence of additives, non-polymer impurities, and polymer degradation. Deprivation of plastics quality......, with respect to recycling, has been shown to happen throughout the plastics value chain, but steps where improvements may happen have been preliminary identified. Example of Cr in plastic samples analysed showed potential spreading and accumulation of chemicals ending up in the waste plastics. In order...

Classification and treatment of distal radius fractures: a survey among orthopaedic trauma surgeons and residents

NARCIS (Netherlands)

M.A.M. Mulders (Marjolein A. M.); D. Rikli; J.C. Goslings (Carel); N.W.L. Schep (Niels)

2017-01-01

textabstractPurpose: Classification, the definition of an acceptable reduction and indications for surgery in distal radius fracturemanagement are still subject of debate. The purpose of this study was to characterise current distal radius fracture management in Europe. Methods: During the European

Individual differences in behavioural plasticities.

Science.gov (United States)

Stamps, Judy A

2016-05-01

Interest in individual differences in animal behavioural plasticities has surged in recent years, but research in this area has been hampered by semantic confusion as different investigators use the same terms (e.g. plasticity, flexibility, responsiveness) to refer to different phenomena. The first goal of this review is to suggest a framework for categorizing the many different types of behavioural plasticities, describe examples of each, and indicate why using reversibility as a criterion for categorizing behavioural plasticities is problematic. This framework is then used to address a number of timely questions about individual differences in behavioural plasticities. One set of questions concerns the experimental designs that can be used to study individual differences in various types of behavioural plasticities. Although within-individual designs are the default option for empirical studies of many types of behavioural plasticities, in some situations (e.g. when experience at an early age affects the behaviour expressed at subsequent ages), 'replicate individual' designs can provide useful insights into individual differences in behavioural plasticities. To date, researchers using within-individual and replicate individual designs have documented individual differences in all of the major categories of behavioural plasticities described herein. Another important question is whether and how different types of behavioural plasticities are related to one another. Currently there is empirical evidence that many behavioural plasticities [e.g. contextual plasticity, learning rates, IIV (intra-individual variability), endogenous plasticities, ontogenetic plasticities) can themselves vary as a function of experiences earlier in life, that is, many types of behavioural plasticity are themselves developmentally plastic. These findings support the assumption that differences among individuals in prior experiences may contribute to individual differences in behavioural

Steady-state, elastic-plastic growth of slanted cracks in symmetrically loaded plates

DEFF Research Database (Denmark)

Nielsen, Kim Lau; Hutchinson, J. W.

2017-01-01

parameter through the plate in the plastic zone at the crack tip. The distribution of the mode I and mode III stress intensity factors along the crack front are obtained for the elastic problem. The out-of-plane bending constraint imposed on the plate significantly influences the mixed mode behavior along......Elastic and elastic-plastic results are obtained for a semi-infinite slanted through-crack propagating in a symmetrically loaded plate strip with the aim of providing theoretical background to commonly observed plate tearing behavior. Were it is not for the slant of the crack through the thickness...... of the plate, the problem would be mode I, but due to the slant the local conditions along the crack front are a combination of mode I and mode III. A three-dimensional formulation for steady-state crack propagation is employed to generate distributions of effective stress, stress triaxiality and Lode...

Durability of wood plastic composites manufactured from recycled plastic

Directory of Open Access Journals (Sweden)

Irina Turku

2018-03-01

Full Text Available The influence of accelerated weathering, xenon-arc light and freeze-thaw cycling on wood plastic composites extruded from a recycled plastic was studied. The results showed that, in general, weathering had a stronger impact on samples made from plastic waste compared to a sample made from virgin material. After weathering, the mechanical properties, tensile and flexural, were reduced by 2–30%, depending on the plastic source. Wettability of the samples was shown to play a significant role in their stability. Chemical analysis with infrared spectroscopy and surface observation with a scan electron microscope confirmed the mechanical test results. Incorporation of carbon black retained the properties during weathering, reducing the wettability of the sample, diminishing the change of mechanical properties, and improving color stability. Keywords: Environmental science, Mechanical engineering, Materials science

Phenotypic plasticity, costs of phenotypes, and costs of plasticity

DEFF Research Database (Denmark)

Callahan, Hilary S; Maughan, Heather; Steiner, Uli

2008-01-01

Why are some traits constitutive and others inducible? The term costs often appears in work addressing this issue but may be ambiguously defined. This review distinguishes two conceptually distinct types of costs: phenotypic costs and plasticity costs. Phenotypic costs are assessed from patterns...... of covariation, typically between a focal trait and a separate trait relevant to fitness. Plasticity costs, separable from phenotypic costs, are gauged by comparing the fitness of genotypes with equivalent phenotypes within two environments but differing in plasticity and fitness. Subtleties associated with both...... types of costs are illustrated by a body of work addressing predator-induced plasticity. Such subtleties, and potential interplay between the two types of costs, have also been addressed, often in studies involving genetic model organisms. In some instances, investigators have pinpointed the mechanistic...

Ultrathin film, high specific power InP solar cells on flexible plastic substrates

International Nuclear Information System (INIS)

Shiu, K.-T.; Zimmerman, Jeramy; Wang Hongyu; Forrest, Stephen R.

2009-01-01

We demonstrate ultrathin-film, single-crystal InP Schottky-type solar cells mounted on flexible plastic substrates. The lightly p-doped InP cell is grown epitaxially on an InP substrate via gas source molecular beam epitaxy. The InP substrate is removed via selective chemical wet-etching after the epitaxial layers are cold-welded to a 25 μm thick Kapton sheet, followed by the deposition of an indium tin oxide top contact that forms the Schottky barrier with InP. The power conversion efficiency under 1 sun is 10.2±1.0%, and its specific power is 2.0±0.2 kW/kg. The ultrathin-film solar cells can tolerate both tensile and compressive stress by bending over a <1 cm radius without damage.

Plastic waste as a resource. Strategies for reduction and utilization of plastic waste

OpenAIRE

Pasqual i Camprubí, Gemma

2010-01-01

Plastic materials have experienced a spectacular rate of growth in recent decades, consequently, production of plastics, and likewise their consumption, has increased markedly since 1950. Moreover, they are lightweight and durable, as well as can be moulded into a variety of products that can be manufactured in many different types of plastic and in a wide range of applications. Inevitably, continually increasing amounts of used plastic are originating daily, resulting in a plastic waste prob...

Bone density of the radius, spine, and proximal femur in osteoporosis

International Nuclear Information System (INIS)

Mazess, R.B.; Barden, H.; Ettinger, M.; Schultz, E.

1988-01-01

Bone mineral density (BMD) was measured in 140 normal young women (aged 20 to 39 years) and in 423 consecutive women over age 40 referred for evaluation of osteoporosis. Lumbar spine and proximal femur BMD was measured using dual-photon absorptiometry ( 153 Gd), whereas the radius shaft measurement used single-photon absorptiometry ( 125 I). There were 324 older women with no fractures, of which 278 aged 60 to 80 years served as age-matched controls. There were 99 women with fractures including 32 with vertebral and 22 with hip fractures. Subsequently, another 25 women with hip fractures had BMD measured in another laboratory; their mean BMD was within 2% of that of the original series. The mean age in both the nonfracture and fracture groups was 70 +/- 5 years. The BMD in the age-matched controls was 20% to 25% below that of normal young women for the radius, spine, and femur, but the Ward's triangle region of the femur showed even greater loss (35%). The mean BMD at all sites in the crush fracture cases was about 10% to 15% below that of age-matched controls. Spinal abnormality was best discriminated by spine and femoral measurements (Z score about 0.9). In women with hip fractures, the BMD was 10% below that of age-matched controls for the radius and the spine, and the BMD for the femoral sites was about 25% to 30% below that of age-matched control (Z score about 1.6). Femoral densities gave the best discrimination of hip fracture cases and even reflected spinal osteopenia. In contrast, neither the spine nor the radius reflected the full extent of femoral osteopenia in hip fracture

Core-powered mass-loss and the radius distribution of small exoplanets

Science.gov (United States)

Ginzburg, Sivan; Schlichting, Hilke E.; Sari, Re'em

2018-05-01

Recent observations identify a valley in the radius distribution of small exoplanets, with planets in the range 1.5-2.0 R⊕ significantly less common than somewhat smaller or larger planets. This valley may suggest a bimodal population of rocky planets that are either engulfed by massive gas envelopes that significantly enlarge their radius, or do not have detectable atmospheres at all. One explanation of such a bimodal distribution is atmospheric erosion by high-energy stellar photons. We investigate an alternative mechanism: the luminosity of the cooling rocky core, which can completely erode light envelopes while preserving heavy ones, produces a deficit of intermediate sized planets. We evolve planetary populations that are derived from observations using a simple analytical prescription, accounting self-consistently for envelope accretion, cooling and mass-loss, and demonstrate that core-powered mass-loss naturally reproduces the observed radius distribution, regardless of the high-energy incident flux. Observations of planets around different stellar types may distinguish between photoevaporation, which is powered by the high-energy tail of the stellar radiation, and core-powered mass-loss, which depends on the bolometric flux through the planet's equilibrium temperature that sets both its cooling and mass-loss rates.

Dynamics of 137Cs in the forests of the 30-km zone around the Chernobyl nuclear power plant

International Nuclear Information System (INIS)

Mamikhin, S.V.; Tikhomirov, F.A.; Shcheglov, A.I.

1997-01-01

Dynamics of the 137 Cs content in the components of the forests in the 30-km zone around the Chernobyl nuclear power plant (NPP) in 1986-1994 are associated mainly with such factors as the size of radioactive particles in the fallout, ecosystem humidification and soil type, tree age. The influence of particle size was especially noticeable between 1986-1987 and was displayed by low biological availability of radionuclides in the near part of the zone (within the 10-km radius circle around the NPP) in comparison with more distant regions (within the 30-km radius circle). Later, the expression of this influence decreased and transfer factor (the ratio of 137 Cs content in overground phytomass to the soil contamination density) became approximately the same for all plots with similar ecological and fallout characteristics. Humidity of landscape and soil type determined the velocity of radionuclide vertical migration in the soil and 137 Cs biological availability. These parameters were maximum for the hydromorphic soils of wet landscapes enriched in organic substance and poor clayey minerals. Differences of 137 Cs accumulation in overground phytomass of trees caused by tree age are displayed in the higher 137 Cs concentration in structural parts of young trees as compared with old ones

Conversion of radius of curvature to power (and vice versa)

Science.gov (United States)

Wickenhagen, Sven; Endo, Kazumasa; Fuchs, Ulrike; Youngworth, Richard N.; Kiontke, Sven R.

2015-09-01

Manufacturing optical components relies on good measurements and specifications. One of the most precise measurements routinely required is the form accuracy. In practice, form deviation from the ideal surface is effectively low frequency errors, where the form error most often accounts for no more than a few undulations across a surface. These types of errors are measured in a variety of ways including interferometry and tactile methods like profilometry, with the latter often being employed for aspheres and general surface shapes such as freeforms. This paper provides a basis for a correct description of power and radius of curvature tolerances, including best practices and calculating the power value with respect to the radius deviation (and vice versa) of the surface form. A consistent definition of the sagitta is presented, along with different cases in manufacturing that are of interest to fabricators and designers. The results make clear how the definitions and results should be documented, for all measurement setups. Relationships between power and radius of curvature are shown that allow specifying the preferred metric based on final accuracy and measurement method. Results shown include all necessary equations for conversion to give optical designers and manufacturers a consistent and robust basis for decision-making. The paper also gives guidance on preferred methods for different scenarios for surface types, accuracy required, and metrology methods employed.

Thermal degradation and plasticizing mechanism of poly(vinyl chloride) plasticized with a novel cardanol derived plasticizer

Science.gov (United States)

Chen, J.; Nie, X. A.; Jiang, J. C.; Zhou, Y. H.

2018-01-01

A natural plasticizer cardanol derivatives glycidyl ether (CGE) was synthesized and employed as a plasticizer for the poly(vinyl chloride). The effect of CGE on thermal degradation of PVC films and its plasticizing mechanism were firstly reported. The molecular structure of CGE was characterized with Fourier transform infrared spectroscopy (FTIR). Thermal properties, degradation properties and compatibility of the PVC films were investigated by Differential scanning calorimeter analysis (DSC), Thermogravimetric analysis (TGA) and FTIR, respectively. Compared with the commercial plasticizers dioctylphthalate (DOP), CGE can endow PVC film with a decrease of 4.31 °C in glass transition temperature (Tg), an increase of 24.01 °C and 25.53 °C in 10% weight loss (T 10) and 50% weight loss (T 50) respectively, and a higher activetion energy of thermal degradation (Ea ).

Small-radius jets to all orders

CERN Document Server

Cacciari, Matteo; Soyez, Gregory; Salam, Gavin; Dasgupta, Mrinal

2015-01-01

With hadron colliders continuing to push the boundaries of precision, it is becoming increas­ ingly important to have a detailed understanding of the subtleties appearing at smaller values of the jet radius R. We present a method to resum all leading logarithmic terms, a'.; Inn R, using a generating functional approach, as was recently discussed in Ref. 1. We study a variety of observables, such as the inclusive jet spectrum and jet vetoes for Higgs physics, and show that small-R effects can be sizeable. Finally, we compare our calculations to existing ALICE data, and show good agreement.

Determination of the root-mean-square radius of the deuteron from present-day experimental data on neutron-proton scattering

International Nuclear Information System (INIS)

Babenko, V. A.; Petrov, N. M.

2008-01-01

The correlation between the root-mean-square matter radius of the deuteron, r m , and its effective radius, ρ, is investigated. A parabolic relationship between these two quantities makes it possible to determine the root-mean-square radius r m to within 0.01% if the effective radius ρ is known. The matter (r m ), structural (r d ), and charge (r ch ) radii of the deuteron are found with the aid of modern experimental results for phase shifts from the SAID nucleon-nucleon database, and their values are fully consistent with their counterparts deduced by using the experimental value of the effective deuteron radius due to Borbely and his coauthors. The charge-radius value of 2.124(6) fm, which was obtained with the aid of the SAID nucleon-nucleon database, and the charge-radius value of 2.126(12) fm, which was obtained with the aid of the experimental value of the effective radius ρ, are in very good agreement with the present-day chargeradius value of 2.128(11) fm, which was deduced by Sick and Trautmann by processing world-average experimental data on elastic electron scattering by deuterons with allowance for Coulomb distortions.

Deformation processes and weakening mechanisms within the frictional viscous transition zone of major crustal-scale faults: insights from the Great Glen Fault Zone, Scotland

Science.gov (United States)

Stewart, M.; Holdsworth, R. E.; Strachan, R. A.

2000-05-01

The Great Glen Fault Zone (GGFZ), Scotland, is a typical example of a crustal-scale, reactivated strike-slip fault within the continental crust. Analysis of intensely strained fault rocks from the core of the GGFZ near Fort William provides a unique insight into the nature of deformation associated with the main phase of (sinistral) movements along the fault zone. In this region, an exhumed sequence of complex mid-crustal deformation textures that developed in the region of the frictional-viscous transition (ca. 8-15 km depth) is preserved. Fault rock fabrics vary from mylonitic in quartzites to cataclastic in micaceous shear zones and feldspathic psammites. Protolith mineralogy exerted a strong control on the initial textural development and distribution of the fault rocks. At lower strains, crystal-plastic deformation occurred in quartz-dominated lithologies to produce mylonites simultaneously with widespread fracturing and cataclasis in feldspar- and mica-dominated rocks. At higher strains, shearing appears to increasingly localise into interconnected networks of cataclastic shear zones, many of which are strongly foliated. Textures indicative of fluid-assisted diffusive mass transfer mechanisms are widespread in such regions and suggest that a hydrous fluid-assisted, grainsize-controlled switch in deformation behaviour followed the brittle comminution of grains. The fault zone textural evolution implies that a strain-induced, fluid-assisted shallowing and narrowing of the frictional-viscous transition occurred with increasing strain. It is proposed that this led to an overall weakening of the fault zone and that equivalent processes may occur along many other long-lived, crustal-scale dislocations.

Optimization of the bubble radius in a moving single bubble sonoluminescence

International Nuclear Information System (INIS)

Mirheydari, Mona; Sadighi-Bonabi, Rasoul; Rezaee, Nastaran; Ebrahimi, Homa

2011-01-01

A complete study of the hydrodynamic force on a moving single bubble sonoluminescence in N-methylformamide is presented in this work. All forces exerted, trajectory, interior temperature and gas pressure are discussed. The maximum values of the calculated components of the hydrodynamic force for three different radii at the same driving pressure were compared, while the optimum bubble radius was determined. The maximum value of the buoyancy force appears at the start of bubble collapse, earlier than the other forces whose maximum values appear at the moment of bubble collapse. We verified that for radii larger than the optimum radius, the temperature peak value decreases.

The effective neutrino charge radius in the presence of fermion masses

International Nuclear Information System (INIS)

Binosi, D.; Bernabeu, J.; Papavassiliou, J.

2005-01-01

We show how the crucial gauge cancellations leading to a physical definition of an effective neutrino charge radius persist in the presence of non-vanishing fermion masses. An explicit one-loop calculation demonstrates that, as happens in the massless case, the pinch technique rearrangement of the Feynman amplitudes, together with the judicious exploitation of the fundamental current relation J α (3) =2(J Z +sinθ w 2 J γ ) α , leads to a completely gauge independent definition of the effective neutrino charge radius. Using the formalism of the Nielsen identities it is further proved that the same cancellation mechanism operates unaltered to all orders in perturbation theory

A measurement of the pion charge radius

International Nuclear Information System (INIS)

Amendolia, S.R.; Badelek, B.; Batignani, G.; Bedeschi, F.; Bertolucci, E.; Bettoni, D.; Bosisio, L.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Giazotto, A.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Ristori, L.; Scribano, A.; Tonelli, G.; Codino, A.; Fabbri, F.L.; Laurelli, P.; Satta, L.; Spillantini, P.; Zallo, A.; Counihan, M.J.; Frank, S.G.F.; Harvey, J.; Storey, D.; Menasce, D.; Meroni, E.; Moroni, L.

1984-01-01

We report a measurement of the negative pion electromagnetic form factor in the range of space-like four-momentum transfer 0.014 2 2 . The measurement was made by the NA7 collaboration at the CERN SPS, by observing the interaction of 300 GeV pions with the electrons of a liquid hydrogen target. The form factor is fitted by a pole form with a pion radius of (rho 2 )sup(1/2) = 0.657 +- 0.012 fm. (orig.)

Interchange instability with line-typing and finite Larmor radius effects

International Nuclear Information System (INIS)

Riordan, J.C.; Hartman, C.W.

1977-01-01

Finite Larmor radius and end effects are included in a treatment of the low-β interchange instability. Higher order modes are shown to be destabilized by incomplete line-tying through an external plasma

Is Bone Grafting Necessary in the Treatment of Malunited Distal Radius Fractures?

Science.gov (United States)

Disseldorp, Dominique J. G.; Poeze, Martijn; Hannemann, Pascal F. W.; Brink, Peter R. G.

2015-01-01

Background Open wedge osteotomy with bone grafting and plate fixation is the standard procedure for the correction of malunited distal radius fractures. Bone grafts are used to increase structural stability and to enhance new bone formation. However, bone grafts are also associated with donor site morbidity, delayed union at bone–graft interfaces, size mismatch between graft and osteotomy defect, and additional operation time. Purpose The goal of this study was to assess bone healing and secondary fracture displacement in the treatment of malunited distal radius fractures without the use of bone grafting. Methods Between January 1993 and December 2013, 132 corrective osteotomies and plate fixations without bone grafting were performed for malunited distal radius fractures. The minimum follow-up time was 12 months. Primary study outcomes were time to complete bone healing and secondary fracture displacement. Preoperative and postoperative radiographs during follow-up were compared with each other, as well as with radiographs of the uninjured side. Results All 132 osteotomies healed. In two cases (1.5%), healing took more than 4 months, but reinterventions were not necessary. No cases of secondary fracture displacement or hardware failure were observed. Significant improvements in all radiographic parameters were shown after corrective osteotomy and plate fixation. Conclusion This study shows that bone grafts are not required for bone healing and prevention of secondary fracture displacement after corrective osteotomy and plate fixation of malunited distal radius fractures. Level of evidence Therapeutic, level IV, case series with no comparison group PMID:26261748

Mixed plastics recycling technology

CERN Document Server

Hegberg, Bruce

1995-01-01

Presents an overview of mixed plastics recycling technology. In addition, it characterizes mixed plastics wastes and describes collection methods, costs, and markets for reprocessed plastics products.

Sex determination from the radius and ulna in a modern South African sample.

Science.gov (United States)

Barrier, I L O; L'Abbé, E N

2008-07-18

With a large number of unidentified skeletal remains found in South Africa, the development of population specific osteometric standards is imperative. Forensic anthropologists need to have access to a variety of techniques to establish accurate demographic profiles from complete, fragmentary and/or commingled remains. No research has been done on the forearm of African samples, even though these bones have been shown to exhibit sexual dimorphism. The purpose of this paper is to develop discriminant function formulae to determine sex from the radius and ulna in a South African population. The sample consisted of 200 male and 200 female skeletons from the Pretoria Bone (University of Pretoria) and Raymond A. Dart (Witwatersrand University) collections. Sixteen standard anthropometric measurements were taken from the radius (9) and ulna (7) and subjected to stepwise and direct discriminant function analysis. Distal breadth, minimum mid-shaft diameter and maximum head diameter were the best discriminators of sex for the radius, while minimum mid-shaft diameter and olecranon breadth were selected for the ulna. Classification accuracy for the forearm ranged from 76 to 86%. The radius and ulna can be considered moderate discriminators for determining sex in a South African group. However, it is advised that these formulae are used in conjunction with additional methods to determine sex.

[Growth behaviour after fractures of the proximal radius: differences to the rest of the skeleton].

Science.gov (United States)

Hell, A K; von Laer, L

2014-12-01

Fractures of the proximal end of the radius in the growth phase have three characteristics: the head of the radius articulates with two joint partners and is therefore indispensable for an undisturbed function of the elbow. The blood supply of the proximal end of the radius is via periosteal vessels in the sense of a terminal circulation which makes it extremely vulnerable. Severe trauma caused either by accidents or treatment, can result in partial or complete necrosis with deformity of the head and neck region of the radius. Radioulnar synostosis and chronic epiphysiolysis are irreversible complications which can occur after excessive physiotherapy. Despite a low potency growth plate, in young patients the proximal end of the radius shows an enormous spontaneous correction of dislocations. Side to side shifts, however, will not be remodeled. Therapy should be as atraumatic as possible. Due to the blood supply situation, with the appropriate indications the spontaneous correction and a brief period of immobilization without physiotherapy should be integrated into the therapy concept. If an operation is necessary, repeated traumatic repositioning maneuvers should be avoided and in case of doubt closed or careful open repositioning can be achieved with intramedullary nailing. In order to take the special characteristics of the proximal radius into consideration, the vulnerability and correction potential must be weighed up against each other. Therapy must be as atraumatic as possible. The spontaneous correction potential should be integrated into the primary therapy without overestimating this potential with respect to the extent and age of the patient.

Sub-nanosecond plastic scintillators

International Nuclear Information System (INIS)

Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

1977-01-01

Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

Sub-nanosecond plastic scintillators

International Nuclear Information System (INIS)

Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

1976-01-01

Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

Finite Larmor radius flute mode theory with end loss

International Nuclear Information System (INIS)

Kotelnikov, I.A.; Berk, H.L.

1993-08-01

The theory of flute mode stability is developed for a two-energy- component plasma partially terminated by a conducting limiter. The formalism is developed as a preliminary study of the effect of end-loss in open-ended mirror machines where large Larmor radius effects are important

Individualist-Collectivist Culture and Trust Radius : A Multilevel Approach

NARCIS (Netherlands)

van Hoorn, André

We apply a multilevel approach to examine empirically the nexus between individualist and collectivist culture on the one hand and people’s radius of trust on the other. People’s trust level (i.e., the intensity with which people trust other people) has been extensively studied. Increasingly,

Phenotypic plasticity in blood–oxygen transport in highland and lowland deer mice

Science.gov (United States)

Tufts, Danielle M.; Revsbech, Inge G.; Cheviron, Zachary A.; Weber, Roy E.; Fago, Angela; Storz, Jay F.

2013-01-01

SUMMARY In vertebrates living at high altitude, arterial hypoxemia may be ameliorated by reversible changes in the oxygen-carrying capacity of the blood (regulated by erythropoiesis) and/or changes in blood–oxygen affinity (regulated by allosteric effectors of hemoglobin function). These hematological traits often differ between taxa that are native to different elevational zones, but it is often unknown whether the observed physiological differences reflect fixed, genetically based differences or environmentally induced acclimatization responses (phenotypic plasticity). Here, we report measurements of hematological traits related to blood–O2 transport in populations of deer mice (Peromyscus maniculatus) that are native to high- and low-altitude environments. We conducted a common-garden breeding experiment to assess whether altitude-related physiological differences were attributable to developmental plasticity and/or physiological plasticity during adulthood. Under conditions prevailing in their native habitats, high-altitude deer mice from the Rocky Mountains exhibited a number of pronounced hematological differences relative to low-altitude conspecifics from the Great Plains: higher hemoglobin concentrations, higher hematocrits, higher erythrocytic concentrations of 2,3-diphosphoglycerate (an allosteric regulator of hemoglobin–oxygen affinity), lower mean corpuscular hemoglobin concentrations and smaller red blood cells. However, these differences disappeared after 6 weeks of acclimation to normoxia at low altitude. The measured traits were also indistinguishable between the F1 progeny of highland and lowland mice, indicating that there were no persistent differences in phenotype that could be attributed to developmental plasticity. These results indicate that the naturally occurring hematological differences between highland and lowland mice are environmentally induced and are largely attributable to physiological plasticity during adulthood. PMID

Orbital Evolution of Dust Particles in the Sublimation Zone near the Sun

Science.gov (United States)

Shestakova, L. I.; Demchenko, B. I.

2018-03-01

We have performed the calculations of the orbital evolution of dust particles from volcanic glass ( p-obsidian), basalt, astrosilicate, olivine, and pyroxene in the sublimation zone near the Sun. The sublimation (evaporation) rate is determined by the temperature of dust particles depending on their radius, material, and distance to the Sun. All practically important parameters that characterize the interaction of spherical dust particles with the radiation are calculated using the Mie theory. The influence of radiation and solar wind pressure, as well as the Poynting-Robertson drag force effects on the dust dynamics, are also taken into account. According to the observations (Shestakova and Demchenko, 2016), the boundary of the dust-free zone is 7.0-7.6 solar radii for standard particles of the zodiacal cloud and 9.1-9.2 solar radii for cometary particles. The closest agreement is obtained for basalt particles and certain kinds of olivine, pyroxene, and volcanic glass.

Time between plastic displacements of elasto-plastic oscillators subject to Gaussian white noise

DEFF Research Database (Denmark)

Tarp-Johansen, Niels Jacob; Ditlevsen, Ove Dalager

2001-01-01

A one degree of freedom elasto-plastic oscillator subject to stationary Gaussian white noise has a plastic displacement response process of intermittent character. During shorter or longer time intervals the oscillator vibrates within the elastic domain without undergoing any plastic displacements...... between the clumps of plastic displacements. This is needed for a complete description of the plastic displacement process. A quite accurate fast simulation procedure is presented based on an amplitude model to determine the short waiting times in the transient regime of the elastic vibrations existing...

Radiographic diagnosis of scapholunate dissociation among intra-articular fractures of the distal radius: interobserver reliability

NARCIS (Netherlands)

Gradl, Gertraud; Neuhaus, Valentin; Fuchsberger, Thomas; Guitton, Thierry G.; Prommersberger, Karl-Josef; Ring, David; Wahegaonkar, Abhijeet L.; Shafritz, Adam B.; Garcia, Aida E.; Caputo, Andrew E.; Terrono, Andrew L.; Spoor, Andy B.; Eschler, Anica; Vochteloo, Anne J. H.; Beumer, Annechien; Barquet, Antonio; Kristan, Anze; van der Zwan, Arnard L.; Berner, Arne; Ilyas, Asif; Jubel, Axel; Sutker, Ben; Nolan, Betsy M.; Petrisor, Brad; Cross, Brian J.; Wills, Brian P. D.; Barreto, Camilo J. R.; Fernandes, Carlos H.; Swigart, Carrie; Zalavras, Charalampos; Goldfarb, Charles A.; Cassidy, Charles; Eaton, Charles; Wilson, Chris; Cheng, Christine J.; Wall, Christopher J.; Walsh, Christopher J.; Jones, Christopher M.; Garnavos, Christos; Klostermann, Cyrus; Kirkpatrick, D. Kay; Eygendaal, Denise; Verbeek, Diederik O. F.; Beeres, Frank J. P.; Thomas, George; Ponsen, Kornelis J.; van den Bekerom, Michel P. J.; Schep, Niels; Kloen, Peter; Haverlag, Robert

2013-01-01

To evaluate the reliability and accuracy of diagnosis of scapholunate dissociation (SLD) among AO type C (compression articular) fractures of the distal radius. A total of 217 surgeons evaluated 21 sets of radiographs with type C fractures of the distal radius for which the status of the

Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

African Journals Online (AJOL)

2017-12-05

Dec 5, 2017 ... variously described as determined by the ocular biometric variables. There have been many studies on the relationship between refractive error and ocular axial length (AL), anterior chamber depth, corneal radius of curvature (CR), keratometric readings as well as other ocular biometric variables such as ...

Investigating Some Technical Issues on Cohesive Zone Modeling of Fracture

Science.gov (United States)

Wang, John T.

2011-01-01

This study investigates some technical issues related to the use of cohesive zone models (CZMs) in modeling fracture processes. These issues include: why cohesive laws of different shapes can produce similar fracture predictions; under what conditions CZM predictions have a high degree of agreement with linear elastic fracture mechanics (LEFM) analysis results; when the shape of cohesive laws becomes important in the fracture predictions; and why the opening profile along the cohesive zone length needs to be accurately predicted. Two cohesive models were used in this study to address these technical issues. They are the linear softening cohesive model and the Dugdale perfectly plastic cohesive model. Each cohesive model constitutes five cohesive laws of different maximum tractions. All cohesive laws have the same cohesive work rate (CWR) which is defined by the area under the traction-separation curve. The effects of the maximum traction on the cohesive zone length and the critical remote applied stress are investigated for both models. For a CZM to predict a fracture load similar to that obtained by an LEFM analysis, the cohesive zone length needs to be much smaller than the crack length, which reflects the small scale yielding condition requirement for LEFM analysis to be valid. For large-scale cohesive zone cases, the predicted critical remote applied stresses depend on the shape of cohesive models used and can significantly deviate from LEFM results. Furthermore, this study also reveals the importance of accurately predicting the cohesive zone profile in determining the critical remote applied load.

Design of roundness measurement model with multi-systematic error for cylindrical components with large radius.

Science.gov (United States)

Sun, Chuanzhi; Wang, Lei; Tan, Jiubin; Zhao, Bo; Tang, Yangchao

2016-02-01

The paper designs a roundness measurement model with multi-systematic error, which takes eccentricity, probe offset, radius of tip head of probe, and tilt error into account for roundness measurement of cylindrical components. The effects of the systematic errors and radius of components are analysed in the roundness measurement. The proposed method is built on the instrument with a high precision rotating spindle. The effectiveness of the proposed method is verified by experiment with the standard cylindrical component, which is measured on a roundness measuring machine. Compared to the traditional limacon measurement model, the accuracy of roundness measurement can be increased by about 2.2 μm using the proposed roundness measurement model for the object with a large radius of around 37 mm. The proposed method can improve the accuracy of roundness measurement and can be used for error separation, calibration, and comparison, especially for cylindrical components with a large radius.

Petrologic and chemical changes in ductile shear zones as a function of depth in the continental crust

Science.gov (United States)

Yang, Xin-Yue

Petrologic and geochemical changes in ductile shear zones are important for understanding deformational and geochemical processes of the continental crust. This study examines three shear zones that formed under conditions varying from lower greenschist facies to upper amphibolite facies in order to document the petrologic and geochemical changes of deformed rocks at various metamorphic grades. The studied shear zones include two greenschist facies shear zones in the southern Appalachians and an upper amphibolite facies shear zone in southern Ontario. The mylonitic gneisses and mylonites in the Roses Mill shear zone of central Virginia are derived from a ferrodiorite protolith and characterized by a lower greenschist facies mineral assemblage. Both pressure solution and recrystallization were operative deformation mechanisms during mylonitization in this shear zone. Strain-driven dissolution and solution transfer played an important role in the mobilization of felsic components (Si, Al, K, Na, and Ca). During mylonitization, 17% to 32% bulk rock volume losses of mylonites are mainly attributed to removal of these mobile felsic components by a fluid phase. Mafic components (Fe, Mg, Ti, Mn and P) and trace elements, REE, Y, V and Sc, were immobile. At Rosman, North Carolina, the Brevard shear zone (BSZ) shows a deformational transition from the coarse-grained Henderson augen gneiss (HAG) to proto-mylonite, mylonite and ultra-mylonite. The mylonites contain a retrograde mineral assemblage as a product of fluid-assisted chemical breakdown of K-feldspar and biotite at higher greenschist facies conditions. Recrystallization and intra-crystalline plastic deformation are major deformation mechanisms in the BSZ. Fluid-assisted mylonitization in the BSZ led to 6% to 23% bulk volume losses in mylonites. During mylonitization, both major felsic and mafic elements and trace elements, Rb, Sr, Zr, V, Sc, and LREE were mobile; however, the HREEs were likely immobile. A shear zone

[Application of biodegradable plastic film to reduce plastic film residual pollution in Chinese agriculture].

Science.gov (United States)

Yan, Changrong; He, Wenqing; Xue, Yinghao; Liu, Enke; Liu, Qin

2016-06-25

Plastic film has become an important agriculture production material in recent years. Over the past three decades, the amount and application area of plastic film have increased steadily, and in 2014, which are 1.4 million tons and more than 180 million hm² respectively. It plays a key role for ensuring the supply of agricultural goods in China. Meanwhile, plastic film residual pollution becomes more and more serious, and in some regions, the amount of plastic film residues has reached over 250 kg/hm². In part of the Northwest region, soil structure of farmland has been destroyed by plastic film residues and then crop growth and farming operations were suppressed. It is recognized as a good choice to replace plastic film with biodegradable plastic film, an effective measure to solve the plastic film residue pollution. Now, it is in a critical stage of study and assessment of biodegradable plastic film in China and fortunately some biodegradable plastic films show effects in the production of potatoes, peanuts and tobacco. Overall, a series of challenges has still been faced by the biodegradable plastic film, mainly including improving the quality of biodegradable plastic products, such as tensile strength, flexibility, improving the controllability of rupture and degradation, enhancing the ability of increasing soil temperature and preserving soil moisture, and to satisfy the demand of crops production with mulching. In addition, it is essential to reduce the cost of the biodegradable film and promote the application of biodegradable film on large-scale. With the development of biodegradable plastic technology and agricultural production environment, the application of the biodegradable film will have a good future.

Non union of the neck of radius: a case report and review of the ...

African Journals Online (AJOL)

Fractures of the neck of radius are frequent in trauma. They happen without being noticed at the moment of injury of the elbow or in the context of polytrauma. A case of non union of the radius neck occurring in a young person due to ignorance, during first consultation has been reported by the authors. They insist on the ...

Ecological plasticity of Trichoderma fungi in leached chernozem

Science.gov (United States)

Svistova, I. D.; Senchakova, T. Yu.

2010-03-01

The autecological properties of Trichoderma fungi ecotypes isolated from the leached chernozem of the forest-steppe zone of the European part of Russia have been studied. We were the first who carried out the complex study of the synecological relations of micromycetes of such kinds in a system including the soil, microbial community, and plants, i.e., their relations with soil saprotrophic fungi, bacteria, actinomycetes, plants, and pathogenic fungi. It was shown that the ecological plasticity of the Trichoderma genus in the soil of this zone is determined by its growth rate, the optimum pH and temperature, the biosynthesis of extracellular hydrolytic enzymes, the biological action of mycotoxins, and the ability for parasitism. The efficiency of the introduction of Trichoderma species typical and atypical for the leached chernozem into this soil and their influence on the structure of the microbial community were evaluated. The T. pseudokoningii ecotype, which produces cellulolytic enzymes, is very promising for industrial biotechnology, and the T. harzianum ecotype can be used in soil biotechnology for the biocontrol of chernozem. The addition of a commercial trichodermin preparation into the chernozem damages the structure of its microbial community.

Nodule detection in digital chest radiography: Summary of the radius chest trial

International Nuclear Information System (INIS)

Haakansson, M.; Baath, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Ruschin, M.; Tingberg, A.; Mattson, S.; Maansson, L. G.

2005-01-01

As a part of the Europe-wide research project 'Unification of physical and clinical requirements for medical X-ray imaging' - governed by the Radiological Imaging Unification Strategies (RADIUS) Group - a major image quality trial was conducted by members of the group. The RADIUS chest trial aimed at thoroughly examining various aspects of nodule detection in digital chest radiography, such as the effects of nodule location, system noise, anatomical noise, and anatomical background. The main findings of the RADIUS chest trial concerning the detection of a lung nodule with a size in the order of 10 mm can be summarised as: (1) the detectability of the nodule is largely dependent on its location in the chest, (2) the system noise has a minor impact on the detectability at the dose levels used today, (3) the disturbance of the anatomical noise is larger than that of the system noise but smaller than that of the anatomical background and (4) the anatomical background acts as noise to a large extent and is the major image component affecting the detectability of the nodule. (authors)

Localized electronic states: the small radius potential approximation

International Nuclear Information System (INIS)

Steslicka, M.; Jurczyszyn, L.

1984-09-01

Using a quasi three-dimensional crystal model we investigate the localized electronic states, generated by the crystal surface covered by foreign atoms. Two such states are found in the first forbidden energy gap and, because of their localization properties, called the Tamm-like and adsorption-like states. Using the small radius potential approximation, the properties of both types of states were discussed in detail. (author)

Plastic fish

CERN Multimedia

Antonella Del Rosso

2015-01-01

In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness.   Artwork by Wolfgang Trettnak. Packaging materials, consumer goods (shoes, kids’ toys, etc.), leftovers from fishing and aquaculture activities… our oceans and beaches are full of plastic litter. Most of the debris from beaches is plastic bottles. “PET bottles have high durability and stability,” explains Wolfgang Trettnak, a chemist by education and artist from Austria, who gave a lecture on this topic organised by the Staff Association at CERN on 26 May. “PET degrades very slowly and the estimated lifetime of a bottle is 450 years.” In addition to the beach litter accumulated from human use, rivers bring several ki...

Fracture heuristics: surgical decision for approaches to distal radius fractures. A surgeon's perspective.

Science.gov (United States)

Wichlas, Florian; Tsitsilonis, Serafim; Kopf, Sebastian; Krapohl, Björn Dirk; Manegold, Sebastian

2017-01-01

Introduction: The aim of the present study is to develop a heuristic that could replace the surgeon's analysis for the decision on the operative approach of distal radius fractures based on simple fracture characteristics. Patients and methods: Five hundred distal radius fractures operated between 2011 and 2014 were analyzed for the surgeon's decision on the approach used. The 500 distal radius fractures were treated with open reduction and internal fixation through palmar, dorsal, and dorsopalmar approaches with 2.4 mm locking plates or underwent percutaneous fixation. The parameters that should replace the surgeon's analysis were the fractured palmar cortex, and the frontal and the sagittal split of the articular surface of the distal radius. Results: The palmar approach was used for 422 (84.4%) fractures, the dorsal approach for 39 (7.8%), and the combined dorsopalmar approach for 30 (6.0%). Nine (1.8%) fractures were treated percutaneously. The correlation between the fractured palmar cortex and the used palmar approach was moderate (r=0.464; p<0.0001). The correlation between the frontal split and the dorsal approach, including the dorsopalmar approach, was strong (r=0.715; p<0.0001). The sagittal split had only a weak correlation for the dorsal and dorsopalmar approach (r=0.300; p<0.0001). Discussion: The study shows that the surgical decision on the preferred approach is dictated through two simple factors, even in the case of complex fractures. Conclusion: When the palmar cortex is displaced in distal radius fractures, a palmar approach should be used. When there is a displaced frontal split of the articular surface, a dorsal approach should be used. When both are present, a dorsopalmar approach should be used. These two simple parameters could replace the surgeon's analysis for the surgical approach.

Plastics in the Marine Environment.

Science.gov (United States)

Law, Kara Lavender

2017-01-03

Plastics contamination in the marine environment was first reported nearly 50 years ago, less than two decades after the rise of commercial plastics production, when less than 50 million metric tons were produced per year. In 2014, global plastics production surpassed 300 million metric tons per year. Plastic debris has been detected worldwide in all major marine habitats, in sizes from microns to meters. In response, concerns about risks to marine wildlife upon exposure to the varied forms of plastic debris have increased, stimulating new research into the extent and consequences of plastics contamination in the marine environment. Here, I present a framework to evaluate the current understanding of the sources, distribution, fate, and impacts of marine plastics. Despite remaining knowledge gaps in mass budgeting and challenges in investigating ecological impacts, the increasing evidence of the ubiquity of plastics contamination in the marine environment, the continued rapid growth in plastics production, and the evidence-albeit limited-of demonstrated impacts to marine wildlife support immediate implementation of source-reducing measures to decrease the potential risks of plastics in the marine ecosystem.

Plastics in the Marine Environment

Science.gov (United States)

Law, Kara Lavender

2017-01-01

Plastics contamination in the marine environment was first reported nearly 50 years ago, less than two decades after the rise of commercial plastics production, when less than 50 million metric tons were produced per year. In 2014, global plastics production surpassed 300 million metric tons per year. Plastic debris has been detected worldwide in all major marine habitats, in sizes from microns to meters. In response, concerns about risks to marine wildlife upon exposure to the varied forms of plastic debris have increased, stimulating new research into the extent and consequences of plastics contamination in the marine environment. Here, I present a framework to evaluate the current understanding of the sources, distribution, fate, and impacts of marine plastics. Despite remaining knowledge gaps in mass budgeting and challenges in investigating ecological impacts, the increasing evidence of the ubiquity of plastics contamination in the marine environment, the continued rapid growth in plastics production, and the evidence—albeit limited—of demonstrated impacts to marine wildlife support immediate implementation of source-reducing measures to decrease the potential risks of plastics in the marine ecosystem.

Selection of polychlorinated plastics in plastic waste by X-ray fluorescence method

International Nuclear Information System (INIS)

Kumasaki, H.; Shinozaki, Y.

1979-01-01

The X-ray fluorescence method using a small source of 55 Fe was examined and found to be applicable for the selection of polychlorinated plastics from plastic waste in model areas in Tokyo designated for investigating their content in the waste. The weight ratios of soft and hard polychlorinated plastics to the total plastic waste estimated by this method were found to be 15.6% and 0.29% respectively. These values agree well with the results obtained with the Beilstein method. (author)

Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

Energy Technology Data Exchange (ETDEWEB)

Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian [SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Wanotayaroj, Chaowaroj [Center for High Energy Physics, University of Oregon,1371 E. 13th Ave, Eugene, OR 97403 (United States)

2015-02-12

Jets with a large radius R≳1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large-R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale rradius jets. In this paper we systematically study and propose new jet re-clustering configurations and show that re-clustered large radius jets have essentially the same jet mass performance as large radius groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

International Nuclear Information System (INIS)

Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj

2015-01-01

Jets with a large radius R≳1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large-R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale rradius jets. In this paper we systematically study and propose new jet re-clustering configurations and show that re-clustered large radius jets have essentially the same jet mass performance as large radius groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

Toxicological Threats of Plastic

Science.gov (United States)

Plastics pose both physical (e.g., entanglement, gastrointestinal blockage, reef destruction) and chemical threats (e.g., bioaccumulation of the chemical ingredients of plastic or toxic chemicals sorbed to plastics) to wildlife and the marine ecosystem.

Pole-strength of the earth from Magsat and magnetic determination of the core radius

Science.gov (United States)

Voorhies, G. V.; Benton, E. R.

1982-01-01

A model based on two days of Magsat data is used to numerically evaluate the unsigned magnetic flux linking the earth's surface, and a comparison of the 16.054 GWb value calculated with values from earlier geomagnetic field models reveals a smooth, monotonic, and recently-accelerating decrease in the earth's pole strength at a 50-year average rate of 8.3 MWb, or 0.052%/year. Hide's (1978) magnetic technique for determining the radius of the earth's electrically-conducting core is tested by (1) extrapolating main field models for 1960 and 1965 downward through the nearly-insulating mantle, and then separately comparing them to equivalent, extrapolated models of Magsat data. The two unsigned fluxes are found to equal the Magsat values at a radius which is within 2% of the core radius; and (2) the 1960 main field and secular variation and acceleration coefficients are used to derive models of 1930, 1940 and 1950. The same core magnetic radius value, within 2% of the seismic value, is obtained. It is concluded that the mantle is a nearly-perfect insulator, while the core is a perfect conductor, on the decade time scale.

Design and evaluation of a portable intra-operative unified-planning-and-guidance framework applied to distal radius fracture surgery.

Science.gov (United States)

Magaraggia, Jessica; Wei, Wei; Weiten, Markus; Kleinszig, Gerhard; Vetter, Sven; Franke, Jochen; John, Adrian; Egli, Adrian; Barth, Karl; Angelopoulou, Elli; Hornegger, Joachim

2017-01-01

During a standard fracture reduction and fixation procedure of the distal radius, only fluoroscopic images are available for planning of the screw placement and monitoring of the drill bit trajectory. Our prototype intra-operative framework integrates planning and drill guidance for a simplified and improved planning transfer. Guidance information is extracted using a video camera mounted onto a surgical drill. Real-time feedback of the drill bit position is provided using an augmented view of the planning X-rays. We evaluate the accuracy of the placed screws on plastic bones and on healthy and fractured forearm specimens. We also investigate the difference in accuracy between guided screw placement versus freehand. Moreover, the accuracy of the real-time position feedback of the drill bit is evaluated. A total of 166 screws were placed. On 37 plastic bones, our obtained accuracy was [Formula: see text] mm, [Formula: see text] and [Formula: see text] in tip position and orientation (azimuth and elevation), respectively. On the three healthy forearm specimens, our obtained accuracy was [Formula: see text] mm, [Formula: see text] and [Formula: see text]. On the two fractured specimens, we attained: [Formula: see text] mm, [Formula: see text] and [Formula: see text]. When screw plans were applied freehand (without our guidance system), the achieved accuracy was [Formula: see text] mm, [Formula: see text], while when they were transferred under guidance, we obtained [Formula: see text] mm, [Formula: see text]. Our results show that our framework is expected to increase the accuracy in screw positioning and to improve robustness w.r.t. freehand placement.

Plasticity and beyond microstructures, crystal-plasticity and phase transitions

CERN Document Server

Hackl, Klaus

2014-01-01

The book presents the latest findings in experimental plasticity, crystal plasticity, phase transitions, advanced mathematical modeling of finite plasticity and multi-scale modeling. The associated algorithmic treatment is mainly based on finite element formulations for standard (local approach) as well as for non-standard (non-local approach) continua and for pure macroscopic as well as for directly coupled two-scale boundary value problems. Applications in the area of material design/processing are covered, ranging from grain boundary effects in polycrystals and phase transitions to deep-drawing of multiphase steels by directly taking into account random microstructures.

THE IMPACT OF SURFACE TEMPERATURE INHOMOGENEITIES ON QUIESCENT NEUTRON STAR RADIUS MEASUREMENTS

Energy Technology Data Exchange (ETDEWEB)

Elshamouty, K. G.; Heinke, C. O.; Morsink, S. M.; Stevens, A. L. [Department of Physics, University of Alberta, CCIS 4-181, Edmonton, AB T6G 2E1 (Canada); Bogdanov, S., E-mail: alshamou@ualberta.ca [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, NY 10027 (United States)

2016-08-01

Fitting the thermal X-ray spectra of neutron stars (NSs) in quiescent X-ray binaries can constrain the masses and radii of NSs. The effect of undetected hot spots on the spectrum, and thus on the inferred NS mass and radius, has not yet been explored for appropriate atmospheres and spectra. A hot spot would harden the observed spectrum, so that spectral modeling tends to infer radii that are too small. However, a hot spot may also produce detectable pulsations. We simulated the effects of a hot spot on the pulsed fraction and spectrum of the quiescent NSs X5 and X7 in the globular cluster 47 Tucanae, using appropriate spectra and beaming for hydrogen atmosphere models, incorporating special and general relativistic effects, and sampling a range of system angles. We searched for pulsations in archival Chandra HRC-S observations of X5 and X7, placing 90% confidence upper limits on their pulsed fractions below 16%. We use these pulsation limits to constrain the temperature differential of any hot spots, and to then constrain the effects of possible hot spots on the X-ray spectrum and the inferred radius from spectral fitting. We find that hot spots below our pulsation limit could bias the spectroscopically inferred radius downward by up to 28%. For Cen X-4 (which has deeper published pulsation searches), an undetected hot spot could bias its inferred radius downward by up to 10%. Improving constraints on pulsations from quiescent LMXBs may be essential for progress in constraining their radii.

THE IMPACT OF SURFACE TEMPERATURE INHOMOGENEITIES ON QUIESCENT NEUTRON STAR RADIUS MEASUREMENTS

International Nuclear Information System (INIS)

Elshamouty, K. G.; Heinke, C. O.; Morsink, S. M.; Stevens, A. L.; Bogdanov, S.

2016-01-01

Fitting the thermal X-ray spectra of neutron stars (NSs) in quiescent X-ray binaries can constrain the masses and radii of NSs. The effect of undetected hot spots on the spectrum, and thus on the inferred NS mass and radius, has not yet been explored for appropriate atmospheres and spectra. A hot spot would harden the observed spectrum, so that spectral modeling tends to infer radii that are too small. However, a hot spot may also produce detectable pulsations. We simulated the effects of a hot spot on the pulsed fraction and spectrum of the quiescent NSs X5 and X7 in the globular cluster 47 Tucanae, using appropriate spectra and beaming for hydrogen atmosphere models, incorporating special and general relativistic effects, and sampling a range of system angles. We searched for pulsations in archival Chandra HRC-S observations of X5 and X7, placing 90% confidence upper limits on their pulsed fractions below 16%. We use these pulsation limits to constrain the temperature differential of any hot spots, and to then constrain the effects of possible hot spots on the X-ray spectrum and the inferred radius from spectral fitting. We find that hot spots below our pulsation limit could bias the spectroscopically inferred radius downward by up to 28%. For Cen X-4 (which has deeper published pulsation searches), an undetected hot spot could bias its inferred radius downward by up to 10%. Improving constraints on pulsations from quiescent LMXBs may be essential for progress in constraining their radii.

Vegetative and reproductive evaluation of hot peppers under different plastic mulches in poly/plastic tunnel

International Nuclear Information System (INIS)

Iqbal, Q.; Amjad, M.; Ahmad, R.

2009-01-01

Since the beginning of civilization, the man has developed technologies to increase the efficiency of food production. The use of plastic mulch in commercial vegetable production is one of these traditional techniques that have been used for centuries. Studies were conducted to assess the efficacy of plastic mulch on growth and yield of two hot pepper hybrids, viz. Sky Red and Maha in poly/plastic tunnel. The treatments were black plastic mulch, clear plastic mulch and bare soil as control. Both hot pepper hybrids mulched with black plastic showed significantly better vegetative growth (plant height, leaf area etc) and fruit yield. Clear plastic mulch significantly increased soil temperature and reduced the number of days to first flower than black plastic mulch and bare soil. However, fruit yield was higher by 39.56 and 36.49% respectively in both hybrids when they were grown on black and clear plastic mulch as compared to bare soil. Overall results indicated that the use of plastic mulch is an ideal option to maximize hot pepper productivity as well as to extend their production season in poly/plastic tunnels. (author)

Theoretical distribution of load in the radius and ulna carpal joint.

Science.gov (United States)

Márquez-Florez, Kalenia; Vergara-Amador, Enrique; de Las Casas, Estevam Barbosa; Garzón-Alvarado, Diego A

2015-05-01

The purpose of this study is to validate a model for the analysis of the load distribution through the wrist joint, subjected to forces on the axes of the metacarpals from distal to proximal for two different mesh densities. To this end, the Rigid Body Spring Model (RBSM) method was used on a three-dimensional model of the wrist joint, simulating the conditions when making a grip handle. The cartilage and ligaments were simulated as springs acting under compression and tension, respectively, while the bones were considered as rigid bodies. At the proximal end of the ulna the movement was completely restricted, and the radius was allowed to move only in the lateral/medial direction. With these models, we found the load distributions on each carpal articular surface of radius. Additionally, the results show that the percentage of the applied load transmitted through the radius was about 86% for one mesh and 88% for the coarser one; for the ulna it was 21% for one mesh and 18% for the coarser. The obtained results are comparable with previous outcomes reported in prior studies. The latter allows concluding that, in theory, the methodology can be used to describe the changes in load distribution in the wrist. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analytical modeling of tube-to-tubesheet joints subjected to plasticity and creep

International Nuclear Information System (INIS)

Bouzid, A.-H.; Laghzale, N-E.

2009-01-01

The mechanism of failure of heat exchanger and steam generator tube-to-tubesheet joints is related to the level of residual stresses produced in the tube expansion and transition zones during the expansion process and their variation during operation. The accurate prediction of these stresses based of the plastic and creep properties of the joint materials involved can help to design for better leak tightness and strength. Existing design calculations are based on an elastic perfectly plastic behavior of the expansion joint materials and do not account for creep. The proposed model is based on a linear strain hardening material behavior and considers the joint contact pressure relaxation with time. The interaction of the tube and the tubesheet is simulated during the process of the application of the expansion pressure and operation. The effects of the gap, material strain hardening and creep properties are to be emphasized. The developed model results are validated and confronted against the more accurate numerical FEA models. (author)

The Annual Glaciohydrology Cycle in the Ablation Zone of the Greenland Ice Sheet: Part 1. Hydrology Model

Science.gov (United States)

Colgan, William; Rajaram, Harihar; Anderson, Robert; Steffen. Konrad; Phillips, Thomas; Zwally, H. Jay; Abdalati, Waleed

2012-01-01

We apply a novel one-dimensional glacier hydrology model that calculates hydraulic head to the tidewater-terminating Sermeq Avannarleq flowline of the Greenland ice sheet. Within a plausible parameter space, the model achieves a quasi-steady-state annual cycle in which hydraulic head oscillates close to flotation throughout the ablation zone. Flotation is briefly achieved during the summer melt season along a approx.17 km stretch of the approx.50 km of flowline within the ablation zone. Beneath the majority of the flowline, subglacial conduit storage closes (i.e. obtains minimum radius) during the winter and opens (i.e. obtains maximum radius) during the summer. Along certain stretches of the flowline, the model predicts that subglacial conduit storage remains open throughout the year. A calculated mean glacier water residence time of approx.2.2 years implies that significant amounts of water are stored in the glacier throughout the year. We interpret this residence time as being indicative of the timescale over which the glacier hydrologic system is capable of adjusting to external surface meltwater forcings. Based on in situ ice velocity observations, we suggest that the summer speed-up event generally corresponds to conditions of increasing hydraulic head during inefficient subglacial drainage. Conversely, the slowdown during fall generally corresponds to conditions of decreasing hydraulic head during efficient subglacial drainage.

Interaction between vegetable oil based plasticizer molecules and polyvinyl chloride, and their plasticization effect

Science.gov (United States)

Haryono, Agus; Triwulandari, Evi; Jiang, Pingping

2017-01-01

Plasticizer molecules are low molecular weight compounds that are widely used in polymer industries especially in polyvinyl chloride (PVC) resin. As an additive in PVC resin, the important role of plasticizer molecules is to improve the flexibility and processability of PVC by lowering the glass transition temperature (Tg). However, the commercial plasticizer like di(2-ethylhexyl)phthalate (DEHP) is known to cause liver cancer, at least in laboratory rats. DEHP can leach out from PVC into blood, certain drug solutions and fatty foods, which has been detected in the bloodstream of patients undergoing transfusion. Vegetable oil based plasticizers have some attractive properties such as non-toxic, bio-degradable, good heat and light stability, renewable resources, and environmentally friendly. Here we discussed the main results and development of vegetable oil based plasticizer, and especially palm oil based plasticizer. The interaction between plasticizer and polymer was discussed from the properties of the plasticized polymeric material.

A method for determining the radius of an open cluster from stellar proper motions

Science.gov (United States)

Sánchez, Néstor; Alfaro, Emilio J.; López-Martínez, Fátima

2018-04-01

We propose a method for calculating the radius of an open cluster in an objective way from an astrometric catalogue containing, at least, positions and proper motions. It uses the minimum spanning tree in the proper motion space to discriminate cluster stars from field stars and it quantifies the strength of the cluster-field separation by means of a statistical parameter defined for the first time in this paper. This is done for a range of different sampling radii from where the cluster radius is obtained as the size at which the best cluster-field separation is achieved. The novelty of this strategy is that the cluster radius is obtained independently of how its stars are spatially distributed. We test the reliability and robustness of the method with both simulated and real data from a well-studied open cluster (NGC 188), and apply it to UCAC4 data for five other open clusters with different catalogued radius values. NGC 188, NGC 1647, NGC 6603, and Ruprecht 155 yielded unambiguous radius values of 15.2 ± 1.8, 29.4 ± 3.4, 4.2 ± 1.7, and 7.0 ± 0.3 arcmin, respectively. ASCC 19 and Collinder 471 showed more than one possible solution, but it is not possible to know whether this is due to the involved uncertainties or due to the presence of complex patterns in their proper motion distributions, something that could be inherent to the physical object or due to the way in which the catalogue was sampled.

Atomic radii for atoms with the 6s shell outermost: The effective atomic radius and the van der Waals radius from {sub 55}Cs to {sub 80}Hg

Energy Technology Data Exchange (ETDEWEB)

Tatewaki, Hiroshi, E-mail: htatewak@nsc.nagoya-cu.ac.jp [Graduate School of Natural Sciences, Nagoya City University, Nagoya, Aichi 467-8501 (Japan); Institute of Advanced Studies in Artificial Intelligence, Chukyo University, Toyota, Aichi 470-0393 (Japan); Hatano, Yasuyo [School of Information Science and Technology, Chukyo University, Toyota, Aichi 470-0393 (Japan); Noro, Takeshi [Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Yamamoto, Shigeyoshi [School of International Liberal Studies, Chukyo University, Nagoya, Aichi 466-8666 (Japan)

2015-06-15

We consider, for atoms from {sub 55}Cs to {sub 80}Hg, the effective atomic radius (r{sub ear}), which is defined as the distance from the nucleus at which the magnitude of the electric field is equal to that in He at one half of the equilibrium bond length of He{sub 2}. The values of r{sub ear} are about 50% larger than the mean radius of the outermost occupied orbital of 6s, . The value of r{sub ear} decreases from {sub 55}Cs to {sub 56}Ba and undergoes increases and decreases with rising nuclear charge from {sub 57}La to {sub 70}Y b. In fact r{sub ear} is understood as comprising two interlaced sequences; one consists of {sub 57}La, {sub 58}Ce, and {sub 64}Gd, which have electronic configuration (4f{sup n−1})(5d{sup 1})(6s{sup 2}), and the remaining atoms have configuration (4f{sup n})(6s{sup 2}). The sphere defined by r{sub ear} contains 85%–90% of the 6s electrons. From {sub 71}Lu to {sub 80}Hg the radius r{sub ear} also involves two sequences, corresponding to the two configurations 5d{sup n+1}6s{sup 1} and 5d{sup n}6s{sup 2}. The radius r{sub ear} according to the present methodology is considerably larger than r{sub vdW} obtained by other investigators, some of who have found values of r{sub vdW} close to .

Tyre effective radius and vehicle velocity estimation: a variable structure observer solution

International Nuclear Information System (INIS)

El Tannoury, C.; Plestan, F.; Moussaoui, S.; ROMANi, N. RENAULT

2011-01-01

This paper proposes an application of a variable structure observer for wheel effective radius and velocity of automotive vehicles. This observer is based on high order sliding approach allowing robustness and finite time convergence. Its originality consists in assuming a nonlinear relation between the slip ratio and the friction coefficient and providing an estimation of both variables, wheel radius and vehicle velocity, from measurement of wheel angular velocity and torque. These signals being available on major modern vehicle CAN (Controller Area Network) buses, this system does not require additional sensors. A simulation example is given to illustrate the relevance of this approach.

Microbial diversity from chlorophyll maximum, oxygen minimum and bottom zones in the southwestern Atlantic Ocean

Science.gov (United States)

Medina-Silva, Renata; de Oliveira, Rafael R.; Pivel, Maria A. G.; Borges, Luiz G. A.; Simão, Taiz L. L.; Pereira, Leandro M.; Trindade, Fernanda J.; Augustin, Adolpho H.; Valdez, Fernanda P.; Eizirik, Eduardo; Utz, Laura R. P.; Groposo, Claudia; Miller, Dennis J.; Viana, Adriano R.; Ketzer, João M. M.; Giongo, Adriana

2018-02-01

Conspicuous physicochemical vertical stratification in the deep sea is one of the main forces driving microbial diversity in the oceans. Oxygen and sunlight availability are key factors promoting microbial diversity throughout the water column. Ocean currents also play a major role in the physicochemical stratification, carrying oxygen down to deeper zones as well as moving deeper water masses up towards shallower depths. Water samples within a 50-km radius in a pockmark location of the southwestern Atlantic Ocean were collected and the prokaryotic communities from different water depths - chlorophyll maximum, oxygen minimum and deep-sea bottom (down to 1355 m) - were described. At phylum level, Proteobacteria were the most frequent in all water depths, Cyanobacteria were statistically more frequent in chlorophyll maximum zone, while Thaumarchaeota were significantly more abundant in both oxygen minimum and bottom waters. The most frequent microorganism in the chlorophyll maximum and oxygen minimum zones was a Pelagibacteraceae operational taxonomic unit (OTU). At the bottom, the most abundant genus was the archaeon Nitrosopumilus. Beta diversity analysis of the 16S rRNA gene sequencing data uncovered in this study shows high spatial heterogeneity among water zones communities. Our data brings important contribution for the characterisation of oceanic microbial diversity, as it consists of the first description of prokaryotic communities occurring in different oceanic water zones in the southwestern Atlantic Ocean.

Handbook of Plastic Welding

DEFF Research Database (Denmark)

Islam, Aminul

The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve...

Sub-micron indent induced plastic deformation in copper and irradiated steel; Deformation plastique induite par l'essai d'indentation submicronique, dans le cuivre et l'acier 316L irradie

Energy Technology Data Exchange (ETDEWEB)

Robertson, Ch

1999-07-01

In this work we aim to study the indent induced plastic deformation. For this purpose, we have developed a new approach, whereby the indentation curves provides the mechanical behaviour, while the deformation mechanisms are observed thanks to Transmission Electron Microscopy (TEM). In order to better understand how an indent induced dislocation microstructure forms, numerical modeling of the indentation process at the scale of discrete dislocations has been worked out as well. Validation of this modeling has been performed through direct comparison of the computed microstructures with TEM micrographs of actual indents in pure Cu (001]. Irradiation induced modifications of mechanical behaviour of ion irradiated 316L have been investigated, thanks to the mentioned approach. An important hardening effect was reported from indentation data (about 50%), on helium irradiated 316L steel. TEM observations of the damage zone clearly show that this behaviour is associated with the presence of He bubbles. TEM observations of the indent induced plastic zone also showed that the extent of the plastic zone is strongly correlated with hardness, that is to say: harder materials gets a smaller plastic zone. These results thus clearly established that the selected procedure can reveal any irradiation induced hardening in sub-micron thick ion irradiated layers. The behaviour of krypton irradiated 316L steel is somewhat more puzzling. In one hand indeed, a strong correlation between the defect cluster size and densities on the irradiation temperature is observed in the 350 deg. C - 600 deg. C range, thanks to TEM observations of the damage zone. On the other hand, irradiation induced hardening reported from indentation data is relatively small (about 10%) and shows no dependence upon the irradiation temperature (within the mentioned range). In addition, it has been shown that the reported hardening vanishes following appropriate post-irradiation annealing, although most of the TEM

Abiotic degradation of plastic films

Science.gov (United States)

Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

2017-01-01

Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

Effect of limiter end loss in finite Larmor radius theory

International Nuclear Information System (INIS)

Berk, H.L.; Kotelnikov, I.A.

1993-08-01

We have examined the effect of incomplete line tying on the MHD flute mode with FLR (finite Larmor radius) effects. We show that the combination of line tying and FLR effects can slow down MHD instability, but cannot produce complete stabilization

Orientation illusions and heart-rate changes during short-radius centrifugation

NARCIS (Netherlands)

Hecht, H.; Kavelaars, J.; Cheung, C. C.; Young, L. R.

2001-01-01

Intermittent short-radius centrifugation is a promising countermeasure against the adverse effects of prolonged weightlessness. To assess the feasibility of this countermeasure, we need to understand the disturbing sensory effects that accompany some movements carried out during rotation. We tested

Plasticity characteristic obtained by indentation

International Nuclear Information System (INIS)

Mil'man, Yu.V.; Chugunova, S.I.; Goncharova, I.V.

2011-01-01

Methods for determination plasticity characteristic δH in the measurement of hardness and nanohardness are considered. Parameter δH characterizes the plasticity of a material by the part of plastic deformation in the total elastic-plastic deformation. The value of δH is defined for metals with different types of crystal lattice, covalent and partially covalent crystals, intermetallics, metallic glasses and quasicrystals. It is discussed the dependence of the plasticity characteristic δH on structural factors and temperature. Parameter δH allows to analyze and compare the plasticity of materials which are brittle at standard mechanical tests. The combination of hardness H, as the strength characteristic, and the plasticity characteristic δH makes possible the better characterization of mechanical behavior of materials than only the hardness H. The examples of plasticity characteristic δH application are represented.

Low temperature uniform plastic deformation of metallic glasses during elastic iteration

International Nuclear Information System (INIS)

Fujita, Takeshi; Wang Zheng; Liu Yanhui; Sheng, Howard; Wang Weihua; Chen Mingwei

2012-01-01

Molecular dynamics simulations and dynamic mechanical analysis experiments were employed to investigate the mechanical behavior of metallic glasses subjected to iteration deformation in a nominally elastic region. It was found that cyclic deformation leads to the formation of irreversible shear transformation zones (STZs) and a permanent uniform strain. The initiation of STZs is directly correlated with the atomic heterogeneity of the metallic glass and the accumulated permanent strain has a linear relation with the number of STZs. This study reveals a new deformation mode and offers insights into the atomic mechanisms of STZ formation and low temperature uniform plastic deformation of metallic glasses.

Laser confocal measurement system for curvature radius of lenses based on grating ruler

Science.gov (United States)

Tian, Jiwei; Wang, Yun; Zhou, Nan; Zhao, Weirui; Zhao, Weiqian

2015-02-01

In the modern optical measurement field, the radius of curvature (ROC) is one of the fundamental parameters of optical lens. Its measurement accuracy directly affects the other optical parameters, such as focal length, aberration and so on, which significantly affect the overall performance of the optical system. To meet the demand of measurement instruments for radius of curvature (ROC) with high accuracy in the market, we develop a laser confocal radius measurement system with grating ruler. The system uses the peak point of the confocal intensity curve to precisely identify the cat-eye and confocal positions and then measure the distance between these two positions by using the grating ruler, thereby achieving the high-precision measurement for the ROC. The system has advantages of high focusing sensitivity and anti-environment disturbance ability. And the preliminary theoretical analysis and experiments show that the measuring repeatability can be up to 0.8 um, which can provide an effective way for the accurate measurement of ROC.

Experiments with elasto-plastic oscillator

DEFF Research Database (Denmark)

Randrup-thomsen, Søren; Ditlevsen, Ove Dalager

1996-01-01

Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...

Experiments with elasto-plastic oscillator