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We calculate quark-antiquark potentials using the relationship between the expectation value of the Wilson loop and the action of a probe string in the string dual. We review and categorize the possible forms of the dependence of the energy on the separation between the quarks. In particular, we examine the possibility of there being a minimum separation for probe strings which do not penetrate close to the origin of the bulk space, and derive a condition which determines whether this is the case. We then apply these considerations to the flavoured resolved deformed conifold background of Gaillard et al. We suggest that the unusual behaviour we observe in this solution is likely to be related to the IR singularity which is not present in the unflavoured case.

CERN Document Server

We complete the study of smooth $Z_3$-quotients of complete intersection Calabi-Yau threefolds by discussing the six new manifolds that admit free $Z_3$ actions that were discovered discovered recently by Braun. These manifolds were missed in an earlier work and complete the web of smooth $Z_3$-quotients in a nice way. We discuss the transitions between these manifolds and include also the other manifolds of the web. This leads to the conclusion that the web of $Z_3$-free quotients of complete intersection Calabi-Yau threefolds is connected by conifold transitions.

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The formation of a quasiequilibrium beam distribution matched to an alternating-gradient quadrupole focusing lattice by means of the adiabatic turn-on of the oscillating focusing field is studied numerically using particle-in-cell simulations. Quiescent beam propagation over several hundred lattice periods is demonstrated for a broad range of beam intensities and vacuum phase advances describing the strength of the oscillating focusing field. Properties of the matched-beam distribution are investigated. In particular, self-similar evolution of the beam density profile is observed over a wide range of system parameters. The numerical simulations are performed using the WARP particle-in-cell code.

Science.gov (United States)

... Accession Number : ADD100229. Title : DEFORMATION BEHAVIOR OF AN OMEGA HARDENED ALPHA-BETA TITANIUM ALLOY,. ...

CERN Document Server

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

UK PubMed Central (United Kingdom)

PurposeTo investigate the utility of consistency metrics, such as inverse consistency, in contour based deformable registration error analysis.Full Text Available

Science.gov (United States)

Sep 3, 2010 ... These higher-quality deformable mirrors will enable diffraction-limited performance for many space-based optical systems such as space-based ...

UK PubMed Central (United Kingdom)

¹⁴C-dated Holocene coastal uplift, conventional and satellite geodetic measurements, and coseismic and aseismic fault slip reveal the pattern of distributed deformation at Taiwan resulting...Full Text Available

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No abstract prepared.

KoreaScience (Korea)

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International Nuclear Information System (INIS)

Investigated are the characteristics of high-temperature plastic deformation the velocity sensitivity of flow stresses, deformation curves, flow stresses, deformation before rupture - as well as the structure of beryllium alloys containing nickel (0.5-4 %), yttrium (0.5-2 %) and aluminium (38 %). The alloys containing nickel (2%) and yttrium (0.5 %) are superplastic, however, deformation before fracture of the alloys is lower than that of the unalloyed beryllium. The singularities of high-temperature plastic flow of the alloys and the causes of deterioration of their plasticity are determined.

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No abstract prepared.

Science.gov (United States)

... crystals and polycrystals. Nevertheless, explosive forming, magnetic forming, etc., are all high-strain-rate processes that ...

International Nuclear Information System (INIS)

A technique for quantitative analysis of growth plates in varus or valgus deformity about the knee has been developed. Computer-generated regions of interest are placed on magnification scintigraphs to divide distal femoral and proximal tibial physes into four equal segments. The ratio of counts in the medial half to counts in the lateral half was studied in 31 children (22 normal, 9 with angular deformity). Normal ratios were 0.74 to 0.98 for femora and 0.98 to 1.20 for tibias. In eight of nine patients with deformity, the ratio was abnormal; in two patients the ratio returned to normal when the deformity ceased to progress.

International Nuclear Information System (INIS)

The influence of deformation on the corrosion behavior of a newly developed multifunctional beta titanium alloy Ti-23Nb-0.7Ta-2Zr-O (mol%) in Ringer's solution at 310 K was evaluated using an electron backscatter diffraction technique and electrochemical measurements. The results showed that the effect of deformation on the corrosion resistance of the beta titanium alloy is complicated. Small levels of plastic deformation are detrimental to the corrosion resistance, whereas large deformations tend to eliminate this detrimental effect.

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Based on techniques of organic solvent extraction and a thermal model experiments of coal-related hydrocarbon, the variation of coal structure and the character of deformed coal-related hydrocarbons were studied when the coal seam at Piagdingshan mine, China was modified by tectonic stress. The results show that the extraction ratio by n-hexane and benzene from the deformed coal approaches that form normal coal, but the extraction ratio by chloroform from the deformed coal is two times more than that from normal coal. The deformed coal has higher solvable low-molecular weight compounds than normal coal. The intermolecular force of deformed coal is relatively small. The deformed coal has low strength and high adsorption capacity, and these determine the outbreak of coal-gas outburst. The extraction yields by chloroform can be taken as an index of forecast risks ...

CERN Document Server

In this paper we study half-BPS type IIB supergravity solutions with multiple $AdS_3\\times S^3\\times M_4$ asymptotic regions, where $M_4$ is either $T^4$ or $K_3$. These solutions were first constructed in [1] and have geometries given by the warped product of $AdS_2 \\times S^2 \\times M_4 $ over $\\Sigma$, where $\\Sigma$ is a Riemann surface. We show that the holographic boundary has the structure of a star graph, i.e. $n$ half-lines joined at a point. The attractor mechanism and the relation of the solutions to junctions of self-dual strings in six-dimensional supergravity are discussed. The solutions of [1] are constructed introducing two meromorphic and two harmonic functions defined on $\\Sigma$. We focus our analysis on solutions corresponding to junctions of three different conformal field theories and show that the conditions for having a solution charged only under Ramond-Ramond three-form fields reduce to relations involving the positions of the poles ...

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The Gordon Research Conference (GRC) on ROCK DEFORMATION was held at II Ciocco from 5/19/02 thru 5/24/02. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

International Nuclear Information System (INIS)

Effect of strain and temperature on high temperature deformation properties of an alpha + beta titanium alloy Ti-6Al-4V has been investigated in the temperature range 800 to 910 deg. C by using the method of cross head speed cycling. On the basis of flow stress strain rate-strain rate sensitivity data and microstructural studies of the undeformed and deformed regions of tensile test pieces, both strain introduced hardening and softening effects were observed during the course of deformation which could be associated with grain coarsening and refining respectively. (author)

International Nuclear Information System (INIS)

The average single-particle field shows a very small pseudo-spin-orbit splitting in the pseudo-spin representation. If this splitting is neglected, pseudo-spin becomes a good quantum number and the resulting scheme (the pseudo-Nilsson model) has a very simple interpretation. The pseudo-spin symmetry embodied in the realistic deformed average field is explored by comparing the single-particle energies and wave functions of the deformed Woods-Saxon model with the corresponding results of the pseudo-Nilsson model. The scheme is used to calculate the magnetic moments of deformed odd-A nuclei of the rare-earth region. (orig.).

Science.gov (United States)

... In the same year, the Revere Copper and Brass Company of America introduced the tandem cold mill, soon followed by ...

International Nuclear Information System (INIS)

The alloy of Ti-Al-Mo-V-Cr system is studied for its structure in a strained state and specific features of #beta#-#alpha# transformation in a #beta#-matrix and deformation twins on ageing. It is determined that preliminary deformation initiates the decomposition of solid solution on aging. In a metastable #beta#-titanium alloy the substructure of deformation twins is shown to vary essentially with aluminium and chromium partial substitution for molybdenum and vanadium

International Nuclear Information System (INIS)

The relationships of hydrogen alloyed #beta#-titanium alloy deformation behaviour to its microstructure and texture are investigated. It is shown that plasticity increases and strain induced texture changes at low hydrogen contents (0.1-0.2 mass %). Possible mechanisms responsible for specific features of #beta#-Ti alloy deformation are discussed. The study is made using alloy VT35 doped with hydrogen

International Nuclear Information System (INIS)

The applicability of conventional strength hypotheses in the long-term creep range was examined by means of multiaxial loaded small and large-scale specimens of 1% CrMoNiV-steel at 550deg C. The experimentally determined deformation behaviour in the primary and secondary creep range was simulated by means of a finite element analysis. The creep deformation capacity is influenced by the degree of multiaxiality. The validity of a strength hypothesis depends on the type of load and on deformation resp. failure criteria. (orig.).

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The development of a twinned microstructure in hexagonal close-packed rolled magnesium compressed in the in-plane direction has been monitored in situ with neutron diffraction. The continuous conversion of the parent to daughter microstructure is tracked through the variation of diffraction peak intensities corresponding to each. Approximately 80% of the parent microstructure twins by 8% compression. Elastic lattice strain measurements indicate that the stress in the newly formed twins (daughters) is relaxed relative to the stress field in the surrounding matrix. However, since the daughters are in a plastically 'hard' deformation orientation, they quickly accumulate elastic strain as surrounding grains deform plastically. Polycrystal modeling of the deformation process provides insight about the crystallographic deformation mechanism involved.

British Library Electronic Table of Contents (United Kingdom)

Ground deformation affecting the Umbria region (central Italy) in the 9-year period from 1992 to 2000 was investigated through multi-temporal Differential Synthetic Aperture Radar Interferometry (DInSAR). For the purpose, the Small BAseline Subset (SBAS) technique was adopted, which allows studying the temporal evolution of the detected deformation at two spatial scales: a low-resolution (regional) scale, and a full-resolution (local) scale. For the analysis, SAR data acquired by the European Remote Sensing (ERS-1/2) satellites along ascending and descending orbits were used. The detected deformation was analysed to investigate its relevance to geophysical, geomorphologic, and human-induced processes that may result in hazardous conditions to the population of Umbria. Low-resolution deform...

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Deformation of the ground can be considered as a sum of volume deformation and shear deformation. At circumferential ground of pile axis, simple shear type of shear deformation becomes main factor of settlement. As shear forces with reverse direction are overlapped at parallel face for pile around face of the ground between the piles, the shear deformation is relaxed. At deeper place from top of the pile, volume deformation becomes larger and component of shear deformation approaches to a pure shear type. In case of the land surface loading type consolidation settlement calculation, a method adopting one dimensional consolidation calculating method using only vertical component within stress obtained by elasticity theory even when investigating multi dimensionally is used widely. In Japanese design standards, the method calculating the ...

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Deformation mechanisms of Mg-Al-Zn (AZ31) alloys were investigated by performing tensile test at room temperature. In fine grain Mg alloys deformed at room temperature, nonbasal slip systems were found to be active as well as basal slip systems because of grain-boundary compatibility effect. Slip-induced grain-boundary sliding occurred as a complementary deformation mechanism to give rise to c-axis component of strain. With increasing grain size, the activation of the nonbasal slip systems was limited near grain boundaries. Instead of grain-boundary sliding, twinning occurred as a complementary deformation mechanism in large grained samples. Orientation analysis of twins indicated that twinning is induced by stress concentration due to the pile up of basal dislocations. The grain-size dependence on deformation mechanism was found to affect yielding behavior both microscopically and ...

International Nuclear Information System (INIS)

Phase transformations occuring during cold deformation in hardened #alpha#+#beta# titanium alloy of the Ti-Al-Mo-Zr-Sn-Si system with 10% summary content of alloying elements are studied by X-ray diffraction analysis. Two stages of trapsformation of metastable #alpha#''-phase are found. A conclusiop is made that ability of the alloy containing #alpha#''-phase to cold deformation is determined by the presence of favourable texture, by high degree of metastability and by volume portion of #alpha#''-phase in the alloy structure.

International Nuclear Information System (INIS)

Lifetimes have been measured in the #pi#h_9_/_2 (yrast) and #pi#i_1_3_/_2 (excited) bands in the nuclei "1"8"1Ir and "1"8"7Au using the Recoil Distance Method (RDM). The results clearly indicate that the #pi#i_1_3_/_2 band exhibits an increased deformation over the #pi#h_9_/_2 band, in keeping with the premise that the delayed crossing in this band is due to enhanced quadrupole deformation. (author). 3 refs, 1 fig, 2 tab.

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Evaluation of grain boundary composition and structure in superplastically deformed AA5083-based alloys (Al-4.5Mg-1.6Mn-0.2Zr) was carried out in a field-emission gun transmission electron microscope (FEG-TEM). During superplastic deformation at high homologous temperatures materials undergo extensive grain boundary sliding (GBS) which creates a flow of defects in the near-boundary region. Recent literature has shown that the grain-boundary composition in Al-Mg alloys is not necessarily the same as the matrix, and that these differences can have an effect on GBS.

International Nuclear Information System (INIS)

(7 Jan 1974). Netherlands Rebel, H. Hauser, G. Schweimer, GW Nowicki,

Science.gov (United States)

... The effects of these voids were more noticeable for tantalum and aluminum electrolytic capacitors, which usually exhibited severe case deformation ...

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Morphological and structural changes of nylon 66 were evaluated during a continuous heat-draw process. Results are discussed.

Science.gov (United States)

In this work we examine a five-dimensional brane-world model with brane structure driven by a real scalar field. From the deformation of a kink-like defect we find a new class of brane solutions containing internal structures which have implications for the way the background space-time is constructed and the way its curvature behaves. Initially, for spin 0 scalar field, we find a zero mode which can be localized on the deformed brane. However, this result can change by the gravitational interaction with the brane internal structure. Analyzing the massive modes of the scalar field, using two different methods, we find resonance structures similar to those found in the study of gravity localization. The main objective here is to observe the contributions of the deformation procedure to the resonances and to the well known field localization methods.

International Nuclear Information System (INIS)

The positive-energy unitary irreducible representations of the q-deformed conformal algebra #delta#C_q = U_q(su(2,2)) are obtained by appropriate deformation of the classical ones. When the deformation parameter q is N -th root of unity, all these unitary representations become finite-dimensional. For his case we discuss in some detail the massless representations, which are also irreducible representations of the q-deformed Poincare subalgebra of #delta#C_q. Generically, their dimensions are smaller than the corresponding finite-dimensional non-unitary representation of su(2,2), except when N = 2 modul h + 1, where h is the helicity of the representations. The latter cases include the fundamental representations with h = #+-#1/2. (author). 10 refs.

International Nuclear Information System (INIS)

Pure Cu of 99.98 wt.% purity has been processed at room temperature by diverse techniques of severe plastic deformation, namely equal-channel angular pressing (ECAP), high pressure torsion (HPT) and a combination of both in order to find out the evolution on the microstructural homogeneity for each of the processes and their combination. Starting with a grain size of #approx#60 #mu#m, severe plastic deformation has been introduced to the material while maintaining the sample dimensions unchanged through the processes of ECAP and HPT. A significant decrease in grain size was observed by transmission electronic microscopy (TEM). Microtensile and microhardness tests were carried out on the deformed material in the three processing conditions. A significant improvement of the tensile strength was promoted with admissible penalization on ductility.

International Nuclear Information System (INIS)

An analysis system for the long-term mechanical behavior of barrier materials (MACBECE: Mechanical Analysis system considering Chemical transitions of BEntonite-based and CEment-based materials) was developed in order to improve the reliability of the evaluation of the hydraulic field which is one of the important environmental conditions in the safety assessment of the TRU waste disposal. MACBECE is the system that calculates the deformation of barrier materials using their chemical property changes as inputs, and subsequently calculates their hydraulic conductivity taking both their chemical property changes and deformation into consideration. By using MACBECE, the long-term deformation and the transition of hydraulic field for the round-type disposal cavities were evaluated, assuming some sets of chemical evolution data as input. Based on the analysis result, it is considered that the influence of the long-term ...

Energy Technology Data Exchange (ETDEWEB)

To clarify the effect of electrostimulated deformation on the fine structure and mechanical properties of polycrystalline molybdenum the experiments on the flattening of wire 0.8 mm in diameter into a strip 0.4 mm thick and its further rolling to 0.1 mm thickness using the electric current of high density in the deformation zone and without it, are carried out. As a result of the electric current use the strip density has increased by more than 20%, the same plasticity being preserved. The changes above are explained by the transformations in the fine structure of the deformed metal, which are manifested in more uniform distribution of dislocations and impurities in the grain boundaries in wide angles of the disoriented subgrains.

International Nuclear Information System (INIS)

Doubly decoupled structures in doubly odd deformed nuclei are reexamined and shown to be composed of a pseudo-spin aligned neutron and a decoupled proton. (orig.).

International Nuclear Information System (INIS)

(1 Apr 1975). United Kingdom Gils, HJ Rebel, H. Nowicki, G. Ciocanel, A.

Science.gov (United States)

... We considered spontaneous radiation of quanta and acoustic phonons (both due to deformational and piezoelectric electron-phonon interaction ...

International Nuclear Information System (INIS)

The electronic structure and properties of the cubic Laves phase (C15) compounds ZrZn_2 and ZrV_2 have been determined using our all-electron full-potential linearized-augmented-plane-wave (FLAPW) method for bulk solids. The computations were performed in two stages: (i) self-consistent warped muffin tin and (ii) self-consistent full potential. Spin-orbit coupling was included after either stage. The effects of the inclusion of the nonspherical terms inside the muffin tins on the eigenvalues is found to be small (of order 1 mRy). However, due to the fact that some of the bands near the Fermi level are flat, this effect leads to a much higher value of the density of states at E/sub F/ in ZnZr_2. The most important difference between the materials ZrZn_2 and ZrV_2 is the position of the d bands derived from the Zr and V atoms. Consequently, these materials have completely different Fermi surfaces. We have investigated the magnetic properties of these compounds by ...

Science.gov (United States)

We argue that published results demonstrate that new insights into human brain function may be obscured by poor and/or limited choices in the data-processing pipeline, and review the work on performance metrics for optimizing pipelines: prediction, reproducibility, and related empirical Receiver Operating Characteristic (ROC) curve metrics. Using the NPAIRS split-half resampling framework for estimating prediction/reproducibility metrics (Strother et al., 2002), we illustrate its use by testing the relative importance of selected pipeline components (interpolation, in-plane spatial smoothing, temporal detrending, and between-subject alignment) in a group analysis of BOLD-fMRI scans from 16 subjects performing a block-design, parametric-static-force task. Large-scale brain networks were detected using a multivariate linear discriminant analysis (canonical variates analysis, CVA) that was tuned to fit the data. We found that tuning the CVA model and spatial smoothing were the most ...

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The neutron deficient Sr and Zr nuclei are studied in the relativistic mean-field approach. Large deformations and shape coexistence are predicted for these nuclei in the vicinity of the proton drip line. The charge radii are found to increase with the removal of neutrons from the semimagic {sup 88}Sr and {sup 90}Zr, in close agreement with the recent isotopic-shift measurements.

International Nuclear Information System (INIS)

We investigate the q-deformation of the BRST algebra, the algebra of the ghost, matter and gauge fields on one spacetime point using the result of the bicovariant differential calculus. There are two nilpotent operations in the algebra, the BRST transformation #delta#_B and the derivative d. We show that one can define the covariant commutation relations among the fields and their derivatives consistently with these two operations as well as the *-operation, the antimultiplicative inner involution. (orig.).

International Nuclear Information System (INIS)

Calculations for a single-j nucleon coupled to an axially symmetric core with both #beta#_2 and #beta#_4 deformation have been performed for "1"8"7Ir. Using #beta#_4=-0.08, consistent with previously measured and predicted values of #beta#_4, the calculated spectrum is competitive with recent calculations assuming an asymmetric core.

International Nuclear Information System (INIS)

Differences of the deformation parameters for the 2"+_1 states of even-even spherical nuclei extracted from electromagnetic excitation #beta#sup(em)_2 and from proton scattering #beta#sup(pp')_2 are discussed. It is found that the ratio #beta#sup(pp')_2/#beta#sup(em)_2 is equal to about unity and that there is a small isotope dependence for several incomplete shell nuclei. (orig.).

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High temperature deformation behavior of AZ31 Mg alloy was investigated in this study on the basis of a processing map ({epsilon} {approx} 0.6). To construct a processing map, compression tests were carried out at various temperatures and strain rates. Two regions of high deformation efficiency ({eta}) were identified as: (1) a dynamic recrystallization (DRX) domain at 250 C and 1/s and (2) a superplasticity domain at 450 C and 10{sup -4}/s. The average grain size observed in the DRX region was considerably smaller (2.9{mu}m) than in any other region. In the superplastic condition, tensile elongation to failure approached to 1040%. At the high Z regions, flow softening occurred resulting from the dynamic recrystallization but below 10{sup 10} of Z value, flow hardening occurred due to the grain growth. Possible deformation mechanisms operating at high temperature were discussed in relation to the activation energy. A ...

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The theory of ..cap alpha.. decay in first-order perturbation theory is presented. The theory is designed for a strongly deformed nucleus in an isomeric state which changes its deformation dynamically through decay from a very deformed to an almost spherical shape. It is shown that other channels are not coupled to the ..cap alpha.. channel in first-order perturbation theory. The collective degrees of freedom of the daughter nucleus are described by shape vibrational states, eigenstates of a Hamiltonian whose potential has two minima. The parent nucleus is described by dynamically coupling the vibrational degrees of freedom to the ..cap alpha..-particle motion and also taking rotations into account. The ..cap alpha.. particle is taken to be a point-like particle. The theory is applied to the ..cap alpha.. decay of the isomeric state of /sub 95//sup 242/Am.

British Library Electronic Table of Contents (United Kingdom)

Spastic equinovarus foot deformity commonly occurs after stroke or head trauma. Management by split anterior tibial tendon transfer to the lateral border of the foot was chosen by the authors. The purpose of that work was to assess the reliability of this method to improve patient's functional autonomy and investigate the relationship between the initial clinical examination findings and the quality of the functional results. 84 feet, operated in 82 patients out of 130, of mean age 46 years, were reviewed at a mean follow-up of 65 months. Very few complications were observed. Toe deformities remain a commonly associated problem. 80 patients were able to walk barefoot, 74 reported an increase in their walking distance, and 73 could regularly wear normal shoes. There is a strong relationship...

British Library Electronic Table of Contents (United Kingdom)

Purpose - The purpose of this paper is to investigate the accuracy of different force calculation methods and their impact on mechanical deformations. For this purpose, a micrometer scaled actuator is considered, which consists of a micro-coil and of a permanent magnet (PM) embedded in a deformable elastomeric layer. Design/methodology/approach - For the magnetic field evaluation a hybrid numerical approach (finite element method/boundary element method (FEM/BEM) coupling and a FEM/BEM/Biot-Savart approach) is used, whereas FEM is implemented for the mechanical deformation analysis. Furthermore, for the magneto-mechanical coupling several force calculation methods, namely the Maxwell stress tensor, the virtual work approach and the equivalent magnetic sources methods, are considered and co...

International Nuclear Information System (INIS)

High temperature deformation behaviour of an experimental Beta-titanium alloy Ti-10V has been studied in the temperature range 800 to 945 degree C by using the method of crosshead speed cycling. Although subgrain formation was observed but the alloy did not exhibit superplastic behaviour in the entire temperature range studied. A very large initial grain size and elongation of grains during the deformation are considered the main factors responsible for absence of superplastic behaviour. The activation energy values for regions II and III of the ln sigma vs. ln small epsilon plots are close to the lower of the two activation energy values proposed together to describe self diffusion in beta-phase suggesting that the rate controlling mechanism is that for lattice diffusion rather then grain boundary diffusion. (author)

International Nuclear Information System (INIS)

Computer experiments imitating specimen strain on tension with constant deformation rate have been carried out. A formation possibility of atmosphere from defects around gliding dislocations (I) and a work of Frank-Read sources (II) have been accounted for. In result deformation curves until stresses do not exceed a critical shear stress were calculated. Influence of effects (I) and (II) was analyzed. It is determined that both by pass of dislocations over defect ''atmospheres'' and dislocation multiplication can cause a peak in flow stress occurrence on the deformation curves. Reasons and conditions of such peak occurrence have been studied. 12 refs.; 9 figs. (author).

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The temperature dependence of the dislocation mobility threshold is investigated on the basis of a dislocation model suggested by Frenkel-Kontorova. The critical value is obtained for the stress/temperature, corresponding to the dislocation depinning from its equilibrium position. The universal behaviour of a barrier height at finite stress and temperature is revealed and investigated.

UK PubMed Central (United Kingdom)

This paper presents a new deformable model using both population and patient-specific statistics to segment the prostate from CT images. There are two novelties in the proposed method. First,...Full Text Available

International Nuclear Information System (INIS)

A survey is given of the influence of surface deformations on heavy ion reactions. Emphasis is put on the effect of zeropoint fluctuations in the entrance channel and on the effect on grazing collisions in terms of an imaginary part of the scattering potential. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Superplasticity of polycrystalline metallic materials is a phenomenon which shows hundreds to thousands of percents of large plastic deformation without necking in a steady state of low stress, when the uni-axial tensile loading is done in some special thermo-mechanical conditions (some limited ranges of properly high temperature and low strain rate). The main mechanism of superplastic phenomenon is the grain boundary sliding, while the main mechanism of usual plastic deformation is the trans-granular sliding. In this research, the possibility of superplastic deformation in a magnesium alloy (AZ31Mg alloy) was experimentally investigated, because generally speaking, the magnesium alloy whose atomic structure is hexagonal does not have enough formability in a form of trans-granular sliding mechanism. In this paper, the detail of experimental results are shown and discussed. Moreover, the constitutive equations of Mg alloy ...

Energy Technology Data Exchange (ETDEWEB)

In this study, isothermal torsion tests were carried out on magnesium AZ31B alloy under constant strain rate conditions, in the range of 250 to 400 C at 0.01, 0.1, and 1.0 s{sup -1}. Alloy flow stress dependence on strain rate and temperature can be described by a power law with activation energy of 130 kJ/mol. Microstructural examination of hot deformed samples shows very fine recrystallized grains decorating grain boundaries of larger gains in the form of a necklace. These fine grains are produced by dynamic recrystallization at the grain boundaries of original grains. Microstructure evolution, based on samples quenched at different strain levels, indicates that increasing deformation strain has little effect on recrystallized grain size but widens the recrystallized region, with full recrystallization achieved at a certain high strain level. Recrystallized grain size increases with increasing deformation temperature and ...

UK PubMed Central (United Kingdom)

PurposeAuto-propagation of anatomical region-of-interests (ROIs) from the planning CT to daily CT is an essential step in image-guided adaptive radiotherapy. The...Full Text Available

UK PubMed Central (United Kingdom)

Congenital deformities involving the coverings of the nervous system are called neural tube defects (NTDs). NTD can be classified as neurulation defects, which occur by stage 12, and postneurulation...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The microstructural development inside the stress induced martensite (SIM) variants in Ti-Ni-Nb alloy with various degrees of deformation have been revealed by electron microscopic observations. The orientation relationship between the SIM and the parent phase has been found: [1{bar 1}0]{sub M}{parallel}[11{bar 1}]{sub B2}, (001){sub M} 5{degree} away from (101){sub B2}. The lattice invariant shear of the SIM variants at the slightly deformed stage is dominantly (11{bar 1}) Type I twin. Besides the ordinary slip, the adjustment and development of the internal secondary twinning from (11{bar 1}) Type I twin to {l_angle}011{r_angle} Type II/ or (011) Type I twin, (001)compound twin and (111) Type I twin happen concurrently or in combination inside the SIM variants with the further deformation. The corresponding deformation mechanisms include stress induced reorientation of SIM substructural bands by the ...

International Nuclear Information System (INIS)

Localized deformation may play a key role in the underlying mechanism of irradiation assisted stress corrosion cracking (IASCC) in light water reactor core components. In this study, four austenitic alloys, 18Cr8Ni, 15Cr12Ni, 13Cr15Ni and 21Cr32Ni, with different stacking fault energies were irradiated to 1 and 5 dpa at 360 deg. C using 3.2 MeV protons. Interrupted constant extension rate tensile (CERT) tests were conducted in a simulated BWR environment to determine IASCC susceptibility. In order to characterize the localized deformation in slip channels and grain boundaries, parallel CERT experiments were also performed in an argon atmosphere. Results show that the IASCC susceptibility of the tested alloys increases with increasing irradiation dose and decreasing stacking fault energy. IASCC tends to initiate at locations where slip channels intersect grain boundaries. Localized deformation in the form of grain boundary ...

UK PubMed Central (United Kingdom)

Water samples from several ponds in Minnesota were evaluated for their capacity to induce malformations in embryos of Xenopus laevis. The FETAX assay was used to assess the occurrence of malformations...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The deformation behavior and structure changes of magnesium alloy AZ31 were studied in compression at temperatures ranging from 523 K to 673 K and at a strain rate of 3 x 10{sup -3} s{sup -1}. They depend sensitively on deformation temperature. At high temperatures, grain fragmentation takes place due to frequent formation of kink bands initially at corrugated grain boundaries and then in grain interiors, followed by full development of new grains in high strain. At lower temperatures, in contrast, twinning takes place in rather coarse grains and kink bands are formed mainly in finer original ones in low strain. It is concluded that new grain evolution can be controlled by a deformation-induced continuous reaction resulting in grain fragmentation by kink bands, i.e. continuous dynamic recrystallization (cDRX). The latter is discussed comparing with conventional, i.e. discontinuous, DRX. (orig.)

International Nuclear Information System (INIS)

In this paper, an investigation was performed on a failure pressure vessel, which was as an anti-freezing heater for General Gas Storage and Distribution (SGZ) system. Evident and serious deformation was observed on the body of the vessel. A metallurgical investigation was conducted to establish the mechanism and cause of deformation of the anti-freezing heater at Daya Bay PWR station in China. The investigation, which was performed on specimens cut from the most serious area deformed of the vessel, included macroscopic examination and microscopy examination. The results of the examinations showed that some lamellar pearlite in the microstructure were already spheroidized. It was confirmed that the vessel was operated at high temperature. Stress analysis for the vessel was conducted. And it was confirmed that, in ideal conditions, the vessel would be deformed at around 420 C. The overall results of the ...

Energy Technology Data Exchange (ETDEWEB)

The cell is modeled as an ellipsoid with shell and the surface stress distribution calculated by means of the Maxwell Stress Tensor. The cell membrane is treated as incompressible material having both bending and shear energies of deformation. Employing the principle of virtual work, cell volume (and hence shape) is computed as a function of the external field strength and orientation with respect to the field. The following results were obtained: (1) The surface stresses that develop or the cell membrane are distributed having both normal and tangential components that act together to produce a rounding of the cell. (2) If the tangential component of the stress is ignored, then higher field strengths are needed to produce similar deformation (shape change) of cells. (3) The threshold value of the applied field, i.e, the field strength at which the volume (shape) of the cell changes abruptly, occurs at approximately 55V/cm. Above the threshold ...

Energy Technology Data Exchange (ETDEWEB)

Methodologies are given for conducting studies to discover and map break deformations in coal strata using various modifications on radiometry, together with the field for their use. Results that were obtained using the IKS-50 device are given.

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The deformation characteristics of pellets of electrolyte-binder (EB) mixes based on MgO were measured under simulated, thermal-battery conditions. Measurements (using a statistically designed experimental strategy) were made as a function of applied pressure, temperature, and percentage of theoretical density for four molten-salt electrolytes at two levels of MgO. The EB mixes are used as separators in Li-alloy thermal batteries. The electrolytes included LiCl-KCI eutectic, LiCl-LiBr-KBr eutectic, LiBr-KBr-LiF eutectic, and a LiCl-LiBr-LiF electrolyte with a minimum-melting composition. The melting points ranged from 313 C to 436 C. The experimental data were used to develop statistical models that approximate the deformation behavior of pellets of the various EB mixes over the range of experimental conditions we examined. This report, discusses the importance of the deformation response surfaces to thermal-battery design.

UK PubMed Central (United Kingdom)

A new 3D model is developed to simulate the self-oscillation of the elongated vocal folds. This model allows for large deformation and longitudinal displacement. The displacement boundary condition...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

The load-carrying capacity and ultimate deformation capacity of timber-concrete composite systems can be significantly influenced by the ductility of the connection between the two materials. The use of more ductile connections can increase the load-carrying capacity of the composite system as well as its ultimate deformation capacity. In this work, the potential increase that might be expected for these two parameters due to the use of ductile connections will be assessed through numerical simulations, taking the non-linear behaviour of the connections into account. Furthermore, the connection ductility required to achieve the maximum load capacity depends on the mechanical properties of the connection as well as on the geometric and mechanical properties of the composite system. There ar...

International Nuclear Information System (INIS)

Nuclear grade production tubing of Alloy 600 was evaluated for stress corrosion cracking (SCC) susceptibility in high purity water at 365, 345, 325, and 290 C. Reverse tube U-bend specimens provided crack initiation data and constant extension rate tests were employed to determine the crack velocities experienced in th crack propagation stage. Initial results indicate that a linear extrapolation of data received from high temperature tests can be used to predict the service life of steam generator tubing that has been plastically deformed or is continually deforming by ''denting.''.

International Nuclear Information System (INIS)

Bulk properties such as the binding energies, r.m.s. radii and deformation parameters are calculated for the light (Z=2-8) even-mass nuclei using deformed relativistic mean-field theory. A comparison between L1, NL1 and NL2 parameter sets are given. The effects of pairing for open-shell nuclei have been investigated. The calculation is extended to nuclei near the proton- and neutron-drip line. Reasonable agreement with experiment is achieved for NL1 and NL2 parameter sets. (orig.).

International Nuclear Information System (INIS)

Posttraumatic tibia valga is a well-recognized complication following fracture of the upper tibial metaphysis in young children. We present a case of a child who developed a valgus deformity following fracture of the proximal tibia and fibula in which quantitative bone scintigraphy at 5 months after injury demonstrated increased uptake at the proximal tibial growth plate with proportionally greater uptake on the medial side. This finding suggests that the valgus deformity in this patient was due to a relative increase in vascularity and consequent overgrowth of the medial portion of the proximal tibial physis.

International Nuclear Information System (INIS)

Nanoindentation was performed on a Mo-alloy single crystal to investigate effects of focused ion beam (FIB) milling on mechanical behavior. On a non-FIB-milled surface, pop-ins were observed on all load-displacement curves corresponding to a transition from elastic to plastic deformation. Similar pop-ins were not detected on surfaces subjected to FIB milling. This difference indicates that FIB milling introduces damage that obviates the need for dislocation nucleation during subsequent deformation. A second effect of FIB milling is that it increased the surface hardness. Together, these effects could be the source of the size effects reported in the literature on micropillar tests.

Energy Technology Data Exchange (ETDEWEB)

Cold deformation of YBa{sub 2}Cu{sub 3}O{sub 7-x}(phase 123, T{sub c} = 88.5-92 K) powders and strips causes partial decomposition of the 123 phase, a reduction in the degree of orthorhombicity of the structure up to almost complete degradation, and a decrease in T{sub c}. When they are deformed, yttrium high temperature superconductors acquire basal (001) (110) texture with high pole density (13-15 arbitrary units), low scattering angle ({+-} 6deg--7deg from the normal direction), and a weak preference for a, b or a + b in the rolling direction; traces of (139) orientations may also be found. This texture is known to be favourable for increasing j{sub k}. The combined effect of cold deformation and a carbon-containing binder leads, however, to a complete loss of superconductivity at 77 K or above. Depending on the regime of subsequent annealing, the following effects may be observed: degradation of the orthorhombic ...

Science.gov (United States)

The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. The gadolinium isotopes have some of the largest neutron capture cross sections. As a consequence they are used in the control rod in reactor fuel assembly. From the basic science point of view, there are seven stable isotopes of gadolinium with varying degrees of deformation. Therefore they provide a good testing ground for the study of deformation dependent structure such as the scissors mode. Decay gamma rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a ...

International Nuclear Information System (INIS)

The results of X-ray and neutron diffraction experiments on molten alkali halides in which some data of our experiments by X-ray diffraction such as those of molten LiCl, NaCl, KCl, LiBr and KBr are included were summarized. The first peak positions in the radial distribution function in molten alkali halides by X-ray or neutron diffraction experiments are always longer than those by computer simulations and the differences of 0.1 -- 0.3 A exceed the experimental error. It seems to be due to the deformation of the electron shell. In the computer simulation, the shell model which has the spherical deformation was expected to have more closer value of the first peak position to the experimental one than the rigid ion model by taking the polarization of ions. However, no change in the first peak position was found. Therefore, the non-spherical deformation of electron shell at the point where ions are in contact with each other ...

International Nuclear Information System (INIS)

Precisely measured differential cross sections for elastic and inelastic scattering from 104 MeV alpha-particles by _4_8Ca, _5_0Ti and _5_2Cr are reported. The analyses aim primarily at the determination of strength, radial shapes and deformation of the scattering potentials, looking for isotonic differences of N=28 isotones. The mean square radii of the (real) potentials are discussed in terms of mean square radius differences of the matter distributions. The isoscalar transition rates derived by coupled channel analyses of the measured cross sections are compared with electromagnetic rates. In addition to the analyses on the basis of a slightly generalized extended optical model a semi-microscopic deformed folding model has been applied, using a density-dependent effective alpha-bound nucleon interaction. Though an excellent description of the data over the full angular range is obtained the resulting values of the ...

International Nuclear Information System (INIS)

The cell's cytoskeleton, providing the cell with structure and shape, consists of a complex array of structural proteins, including microtubules, microfilaments and intermediate filaments. Intermediate filaments play a crucial role in mechanotransduction and in providing mechanical stability to cells, in particular under large deformation. By utilizing molecular simulation, here we report a nanomechanical analysis of vimentin intermediate filament dimers, the basic building blocks of intermediate filaments. We describe a detailed analysis of the mechanical properties and associated deformation mechanisms, and find that mechanical stretch induces a transition from alpha-helices to beta-sheets, a phenomenon known as alpha-beta transition. A comparison of the Young's modulus predicted from simulation with experimental measurements is provided, and good agreement is found. We present an analysis of structural changes during ...

Energy Technology Data Exchange (ETDEWEB)

Deformation in the overburden proves useful in deducing spatial and temporal changes in the volume of a producing reservoir. Based upon these changes we estimate diffusive travel times associated with the transient flow due to production, and then, as the solution of a linear inverse problem, the effective permeability of the reservoir. An advantage an approach based upon travel times, as opposed to one based upon the amplitude of surface deformation, is that it is much less sensitive to the exact geomechanical properties of the reservoir and overburden. Inequalities constrain the inversion, under the assumption that the fluid production only results in pore volume decreases within the reservoir. We apply the formulation to satellite-based estimates of deformation in the material overlying a thin gas production zone at the Krechba field in Algeria. The peak displacement after three years of gas production is approximately ...

Energy Technology Data Exchange (ETDEWEB)

Together with an investigation on the deformation behavior of hot and cold rolled strip edge, the edge-drop control was explained in characteristics and result of application to the commercial mill by the tapered-crown work roll (WR) shifting mill. From a cold rolling experiment, three-dimensional material flow was known to be generated in the vicinity of edge also at the time of rolling the strip, and which generation influences that of edge-drop. Almost linearly relative to the flattened deformation of WR, the edge-drop enlarges with enlargement in that deformation. The number of stands to be applied to the tapered-crown WR shifting mill in the tandem cold mill is determined by the location as far as which the strip is to be controlled in edge-drop. In case of improving it to obtain the edge-drop-free strip, all the stands are required to be equipped with tapered-crown WR shifting mill. By applying a tapered-crown WR ...

Energy Technology Data Exchange (ETDEWEB)

Determination of stacking fault energy (SFE) of the austenite phase of a duplex stainless steel DIN W.-Nr.: 1.4462 has been carried out using transmission electron microscopy. Furthermore, cold rolling tests and microstructural analysis have been realized in order to allow a detailed discussion of the obtained SFE-values. The results of this investigation indicate that the stacking fault energy of the austenite phase within the duplex stainless steel is lower than of one-phase austenitic stainless steels. This is justified by the chemical composition, mainly by the Cr and Ni alloying contents. Nevertheless, work hardening of the austenite during cold deformation is not as accentuated as expected by the SFE-values, because at higher deformation levels the deformation mainly occurs within the ferrite phase 7 refs., 5 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a ...

Energy Technology Data Exchange (ETDEWEB)

This work is based on the study of cesium ({sup 118,146}Cs) and francium ({sup 207-213}Fr,{sup 220-228}Fr) isotopes by hyperfine atomic spectroscopy and on the interpretation of these results from the nuclear physics point of view. The measured nuclear quantities are: the spin, the magnetic moment, the electric quadrupole moment and the mean square charge radius. The experimental method which is based on hyperfine optical pumping with a tunable laser, followed by magnetic analysis of the atoms is described in the first part. Results related to atomic physics are also presented. In the second part, these data are interpreted in the framework of nuclear models. The deformation of light cesium isomers are compared to values obtained from a theoretical self-consistent calculation. Heavy francium isotopes are situated in an area where the existence of static octupole deformations have been predicted. The odd-even staggering measured on the mean ...

Energy Technology Data Exchange (ETDEWEB)

We compare experimental measurements of inhomogeneous plastic deformation in a Ni bicrystal with crystal-plasticity simulations. Polychromatic X-ray microdiffraction, orientation imaging microscopy and scanning electron microscopy, were used to characterize the geometrically necessary dislocation distribution of the bicrystal after uniaxial tensile deformation. Changes in the local crystallographic orientations within the sample reflect its plastic response during the tensile test. Elastic strain in both grains increases near the grain boundary. Finite element simulations were used to understand the influence of initial grain orientation and structural inhomogeneities on the geometrically-necessary dislocations arrangement and distribution and to understand the underlying materials physics.

Energy Technology Data Exchange (ETDEWEB)

The buckling behaviors of double-walled carbon nanotubes (DWCNTs) under torsion are investigated by using molecular dynamics (MD) simulations. The effect of length on the torsional buckling behaviors of DWCNTs is examined for the first time. The simulation results show that the DWCNTs experience gradual or simultaneous buckling deformations depending on their lengths. In addition, the effect of the inner tube in a DWCNT on its torsional buckling behavior is also examined. The presence of the inner tube triggers van der Waals (vdW) interactions between it and the outer tube and thus leads to a stiffening effect of the DWCNT against torsional deformation. Whether the ends of the inner tube are free or fixed and whether it is subject to a torque or not, the critical torque and the critical torsional angle of the outer tube are only marginally affected.

British Library Electronic Table of Contents (United Kingdom)

In this study polycrystalline specimens of as-cast DyCu with B2 crystal structure were compressed to different strains at room temperature to test if stress-induced phase transformation and twinning occur during deformation. In these tests DyCu exhibited high ductility with plastic strain as high as 35% and ultimate compressive strength of ~790MPa. X-ray diffraction and transmission electron microscopy (TEM) showed no indications that DyCu had undergone stress-induced phase transformation or twinning. -type dislocations have been observed to play an important role for imparting the ductile behavior. TEM analyses showed the presence of second phases, Dy2O3 and DyCu2 within the DyCu. The mechanisms of ductility and impurity phase formation are discussed.

Energy Technology Data Exchange (ETDEWEB)

There have been many stress measurements on welds by neutron diffraction over the past 20 years but there are still a number of serious experimental issues that are often not addressed. The primary fact is that the microstructure generally changes across the weld and accompanying this may be a change in the concentration of strengthening elements in solution. This will lead to a shift in lattice spacing which may be incorrectly interpreted as a strain. Secondly, a gradient of plastic deformation near the weld may be expected. Since plastic deformation by application of a stress always generates intergranular (type-2) strains this may lead to a range of intergranular effects superposed on the conventional weld-related strains. The effects are illustrated by neutron diffraction studies of Zr-4, ferritic and austenitic welds where chemistry, intergranular effects and crystallographic texture can all play a role.

British Library Electronic Table of Contents (United Kingdom)

This experimental study investigates the effectiveness of crossed inclined bars (X-bars) as joint shear reinforcement in exterior reinforced concrete beam-column connections under cyclic deformations. Test results of 20 joint subassemblages with various reinforcement ratios and arrangements including X-bars in the joint area are presented. The X-type, non-conventional reinforcement is examined as the only joint reinforcement and in combination with common stirrups or vertical bars. The experimental results reported herein include full loading cycle curves, energy dissipation values and a categorization of the observed damage modes. Based on the comparisons between the overall hysteretic responses of the tested specimens, it is deduced that joints with X-bars exhibited enhanced cyclic perfo...

British Library Electronic Table of Contents (United Kingdom)

Uphalda gneisses (UG) is a crystalline klippe located near Srinagar in Garhwal Himalaya. These gneisses are compared with Debguru porphyroids (DP) (?Ramgarh group) of Garhwal?Kumaun Himalaya and Baragaon mylonitic gneisses (BMG) of Himachal Himalaya. Petrographic study reveals that the deformation of UG was initiated at higher temperature (above 350?C) and continued till lowering of temperature and deformation led to the mylonitization. Geochemically, these granitic gneisses (UG, DP and BMG) exhibit similar composition. Features such as high molecular A/CNK value (>1), presence of normative corundum and absence of normative diopside, enhanced Rb/Sr, Rb/Zr ratios, enrichment of Th and containing rounded zircons support their crustally-derived S-type granitic nature. The linear plot in major...

British Library Electronic Table of Contents (United Kingdom)

The microstructure and tensile properties of Ti-44Al-6V-3Nb-0.3Y (at.%) alloy after canned forging were investigated. SEM results showed that the TiAl pancake exhibits inhomogeneous microstructure, which can be ascribed to the temperature drop and friction between billet and outer pack during forging, as well as the intrinsic anisotropy of lamellar colony. By means of TEM observation and EBSD analysis, the microstructure in the dominant area of the pancake was further characterized. This deformation area consists of 87.7% content of g grains plus some refined lamellar colonies and the rest of B2 grains. The grain size ranges between 1mm and 8.5mm. High-angle boundaries dominate the deformation microstructure, several substructures and twins are observed as well. Additionally, current forge...

British Library Electronic Table of Contents (United Kingdom)

Regularities of deformation-induced dissolution of a surface layer of iron oxides in matrixes of iron-based alloys with bcc and fcc lattices have been studied by the methods of M?ssbauer spectroscopy, transmission electron microscopy, and X-ray diffraction. A method of producing iron alloys strengthened by dispersed oxide nanoparticles and alloyed with elements possessing a high affinity to oxygen (titanium and yttrium) has been proposed, which implies a dynamic dissolution of a surface layer of iron oxides upon strong cold deformation and a precipitation of secondary yttrium and titanium nanooxides upon a subsequent high-temperature sintering of mechanically alloyed powders. There has been demonstrated a possibility of oxide strengthening of pure iron upon its interaction with air without...

International Nuclear Information System (INIS)

General expressions for the interlattice displacements of the A-15 structure compounds are obtained in terms of the strain components making use of the deformation theory. The nature of the interlattice displacements of all the 8 atoms in the unit cell is discussed. It is found that the interlattice displacements occur in such a way that the pair of atoms along any linear chain move in opposite directions with equal magnitudes. Expression for the strain energy of these compounds is developed using deformation theory and this is compared with the strain energy expression from continuum theory to obtain the elastic constants. The theoretical values of the elastic constants fairly agree with the experimental values for V_3Si, V_3Ge and Nb_3Sn. (author).

Energy Technology Data Exchange (ETDEWEB)

This paper presents experimental data and an computational model of the cold spray solid particle impact process. Copper particles impacting onto a polished stainless steel substrate are examined. The high velocity impact causes significant plastic deformation of both the particle and the sub- strate, but no melting is observed. The plastic deformation exposes clean surfaces that, under the high impact pressures, result in significant bond strengths between the particle and substrate. Experimental measurements of the splat and crater sizes compare well with the numerical calculations. It is shown that the crater depth is significant and increases with impact velocity. However, the splat diameter is much less sensitive to the impact velocity. It is also shown that the geometric lengths of the splat and crater scale linearly with the diameter of the impacting particle. It is hoped that the results presented will allow better understanding of the ...

International Nuclear Information System (INIS)

A study was made into microstructure and texture of cold rolled titanium alloy VT-35 with various hydrogen content aimed to reveal hydrogen influence on the mechanism of cold plastic deformation by rolling. Experiments were carried out using sheets 1.2 mm thick hydrogenated up to hydrogen concentrations from 0.06 to 0.554 mass. %. All specimens constituted a single-phase FCC #beta#-solid solution. It is shown that small hydrogen additions have a plasticizing effect on #beta#-titanium alloys in their cold rolling. The character of texture is dependent on hydrogen concentration and determined by deformation mechanism. 6 refs.; 5 figs.

International Nuclear Information System (INIS)

The grain size dependence of the tensile properties and the deformation mechanisms responsible for those properties are examined for Mg alloy, AZ31B, sheet. Specifically, the Hall-Petch effect and strain anisotropy (r-value) are characterized experimentally, and interpreted using polycrystal plasticity modeling. {1 0 . 2} extension twins, {1 0 . 1} contraction twins, and so-called 'double-twins' are observed via microscopy and diffraction-based techniques, and the amount of twinning is found to increase with increasing grain size. For the sheet texture and tensile loading condition examined, {1 0 . 2} extension twinning is not expected, yet the polycrystal plasticity model predicts the observed behavior, including this 'anomalous' tensile twinning. The analysis shows that the Hall-Petch strength dependence, of the polycrystal as a whole, is primarily determined by the grain size dependence of the strength of the prismatic slip systems.

Energy Technology Data Exchange (ETDEWEB)

In this paper, for an acceleration of utilization of magnesium alloy which is being interested in recent years, friction welding of AZ31 magnesium alloy was carried out, and the joint performance was discussed in relation to the deformation heat input in the upset stage and upset loss as a evaluation factor. Where, the deformation heat input in the upset stage is mechanical work represented by the product of upset speed and axial pressure. As a result, it was made clear that the friction welding of AZ31 magnesium alloy was easy in the atmosphere, and good welded joints without a non- adhesion area at the weld interface could de obtained. Moreover, the evaluation factors discussed were possible to evaluate to joint performance. (orig.)

British Library Electronic Table of Contents (United Kingdom)

Around the world there is a small industry of non-governmental organisations that provide health care in niche areas that cannot be met by national health care provision. One topic is facial deformity that can have a dramatic effect on quality of life. In this study we investigate the morbidity and outcome of a British surgical team working for a 2-week period in Ethiopia. Thirty-five patients who presented with facial deformities had 47 operations during a 2-week period. Data were recorded for a minimum of 3 weeks postoperatively. Operative techniques were classified as simple or complex. Postoperative complications were assessed and classified as major, intermediate, and minor. In addition, the character of each complication was recorded and the cause elucidated. After 3 weeks the clinic...

British Library Electronic Table of Contents (United Kingdom)

This paper presents the results of single-fiber pullout tests for deformed and smooth steel fibers embedded in the newly developed very-high strength concrete (VHSC) matrixes. The pullout test program involved four types of steel fibers, eight compressive strengths of VHSC matrixes, and two normal concrete strengths. Test results have shown that pullout behavior of different steel fiber reinforced VHSC composites is influenced by the matrix strength and fiber end condition (smooth, flat end, or hooked). Results reveal that both maximum pull-out load and total pullout energy increases as matrix strength increases for all deformed fibers that did not rupture. The test results also indicated that the increase in total pullout energy is more significant than that in peak load.

International Nuclear Information System (INIS)

Deformations of topological open string theories are described, with an emphasis on their algebraic structure. They are encoded in the mixed bulk-boundary correlators. They constitute the Hochschild complex of the open string algebra - the complex of multilinear maps on the boundary Hilbert space. This complex is known to have the structure of a Gerstenhaber algebra (Deligne theorem), which is also found in closed string theory. Generalising the case of function algebras with a B-field, we identify the algebraic operations of the bulk sector, in terms of the mixed correlators. This gives a physical realisation of the Deligne theorem. We translate to the language of certain operads (spaces of d-discs with gluing) and d-algebras, and comment on generalisations, notably to the AdS/CFT correspondence. The formalism is applied to the topological A- and B-models on the disc. (author)

Energy Technology Data Exchange (ETDEWEB)

There are two types in quench distortion of steel parts: thermal distortion and transformation distortion. Quench distortion is caused mainly by uneven cooling rate of steel parts from Austenitising temperature. The rapid cooled side is lengthened (convex deformation); the slow cooled side is shortened (concave deformation). So, to control the quench distortion, it is necessary to regulate the cooling rate of steel parts during quenching. TWO COMPONENTS produce the quench distortion of steel parts: the thermal stress and transformation stress. Generally, the effect of the thermal stress on the quench distortion is stronger than the transformation stress. The quench distortion is caused by uneven cooling rate of the steel parts, from Austenitising temperature to Ms point and Ms-Mf range. So, to control the quench distortion, it is very important to regulate the cooling rate of the steel parts during quenching. The purpose of this paper is to ...

Energy Technology Data Exchange (ETDEWEB)

The final report for a Laboratory Directed Research and Development project entitled, ``Capturing Recrystallization of Metals in a Multiscale Materials Model'' is presented. In this project, deformation and recrystallization processes have been followed experimentally and theoretically in order to incorporate essential mechanisms from the defect (dislocation) and grain size length scales. A nonlinear rotational gradient theory has been developed which enables the incorporation of microstructural parameters. The evolution of these parameters during deformation and recrystallization has been characterized qualitatively and quantitatively, applying various electron optic techniques ranging over several length scales. The theoretical and experimental framework developed is general. It has been exemplified by an application to recrystallization in single crystals and bicrystals of aluminum. The recrystallization process has been ...

British Library Electronic Table of Contents (United Kingdom)

Abstract: We have performed petrographic and spectroscopic studies of brown diamonds from an eclogite xenolith from the Udachnaya pipe (Yakutia, Russia). Brown diamonds are randomly intermixed with colorless ones in the rock and often located at the grain boundaries of clinopyroxene and garnet. Brown diamonds can be characterized by a set of defects (H4, N2D and a line at 490.7nm) which are absent in colorless diamonds. This set of defects is typical for plastically deformed diamonds and indicates that diamonds were likely annealed for a relatively short period after deformation had occurred. Excitation of brown colored zones with a 632.8nm He-Ne laser produced the typical diamond band plus two additional bands at 1730cm^-^1 and 3350cm^-^1. These spectral features are not genuine Raman ban...

CERN Document Server

Mono-layers of stearic and behenic acids deposited with the Langmuir-Blodgett technique, were used as aligning films in nematic liquid crystal cells. During the filling process the liquid crystal adopts a deformed quasi-planar alignment with splay-bend deformation and preferred orientation along the filling direction. This state is metastable and transforms with time into homeotropic once the flow has ceased. The transition is accompanied by formation of disclination lines which nucleate at the edges of the cell. The lifetime of the metastable splay-bend state was found to depend on the cell thickness. On heating, anchoring transition from quasi-homeotropic to degenerate tilted alignment in form of circular domains takes place near the transition to the isotropic phase. The anchoring transition is reversible with a small hysteresis.

International Nuclear Information System (INIS)

The nuclear shapes of transitional Mo isotopes are calculated by means of a model based on the cranking approximation and the Strutinksy method. The recent experimental results of the high-spin spectroscopy and lifetime measurement of "8"7Mo are studied in detail and explained by the evolution of the #gamma#-deformation with the quasiparticle configurations. The shape calculations with the modified-harmonic-oscillator potential give a critical neutron number N #>=# 47 for the spherical shape of the Mo isotopes. (orig.).

International Nuclear Information System (INIS)

The dependence of Tsub(c) on composition and deformation is calculated and compared with the corresponding dependence for Tsub(m). It is shown that superconducting and structural properties of A-15 compounds can be described, at least qualitatively, by the quasi-one-dimensional model previously developed by the authors. The superconductivity mechanism is assumed to be analogous to the BCS theory. The upper critical field Hsub(c2) of the V_3Si or Nb_3Sn compounds is found to be much greater than that in V or Nb.

International Nuclear Information System (INIS)

Structure of ferrite in drawn pearlitic steel containing 0.9 mass% C was investigated with X-ray diffraction technique using synchrotron radiation. In the detailed analysis of diffraction peaks of ferrite during the drawing process, it was experimentally revealed that the transformation of ferrite from bcc to bct due to the supersaturation of carbon in ferrite of heavily drawn pearlitic steel.

Energy Technology Data Exchange (ETDEWEB)

An experimental technique has been developed to examine the interaction between deformation and the exposure of certain high temperature structural alloys to oxidizing molten salt environments. The experimental program involved performing a series of long-term tensile tests over a wide range of strain rates. Fracture strain reduction in area and ultimate strength (UTS) were monitored as parameters indicative of an alloy's susceptibility to environmental degradation. For Incoloy Alloy 800 tested at 600/sup 0/C in the salt medium and at initial strain rates between 2 x 10/sup -7/ sec/sup -1/ and 1 x 10/sup -5/ sec/sup -/1 no appreciable loss of ductility, as measured by reduction in area, was observed relative to control specimens tested in air at the same temperature and strain rates. Similarly, fracture strain and UTS were essentially unaffected by exposure to the oxidizing environment. The structure of the oxide film formed by contact of the specimens to ...

International Nuclear Information System (INIS)

The essential difference as well as the apparent identity between the triaxial-rotor model and the gamma-vibrational model have been discussed. From the gamma decay mode, the [19/2"-]_1 states of the j = 11/2"- family in "1"8"7Ir and "1"8"9Ir have been identified as the K = j + 4 states, the presence of which contradicts the particle plus triaxial-rotor model. (author).

Energy Technology Data Exchange (ETDEWEB)

The reconstruction of steel lining of the FFTF reactor building is described. The cold part of the lining has a simple structure and represents a steel sheet of 6.35 mm thickness welded to I-shaped imbedded in concrete, the hot part is meant for resisting the hot sodium contacting with it. The reconstruction has been reduced to the substitution of usual lining, the sheets of which are fixed in such a way that dangerous strains in metal arising at evaporation are excluded by the new structure admitting sheet deformation.

Energy Technology Data Exchange (ETDEWEB)

The electrical resistivity at low temperatures (T = 10 to 90 K) of the lithium isotopes /sup 6/Li and /sup 7/Li and of an isotopic mixture /sup 7 +6/Li has been studied. The specimens contained a small amount of chemical impurities. An appreciable difference was observed in the temperature dependence of the resistivity produced both by deformation of the phonon spectrum, related to the change in isotopic composition, and by the presence of chemical impurities making the nonequilibrium part of the electron distribution function more isotropic.

International Nuclear Information System (INIS)

A series of Model Tests of Embedment Effect on Reactor Buildings has been carried out by the Nuclear Power Engineering Corporation (NUPEC), under the sponsorship of the Ministry of International Trade and Industry (MITI) of Japan. Seismic response of an embedded reactor building is greatly affected by the non-linearity of the backfill soil. However, quite few experimental data have been obtained so far. The objective of this study is to qualitatively evaluate the non-linear behavior of the backfill soil through shaking table tests. Its effects to the seismic response of a reactor building constructed at a soft rock site can be made clear through the tests. Non-linear effects of the backfill soil on the seismic response of the embedded reactor building model were evaluated experimentally. Based on the sinusoidal and seismic wave excitation tests, the following conclusions were obtained regarding the changes in vibrational characteristics of the building model which occurred according to ...

Energy Technology Data Exchange (ETDEWEB)

Two aspects of the deformation behavior of magnesium sheets are the subject of this paper. First it will give a mechanical characterization of a commercial magnesium with a focus on the anisotropy and the possible microstructural causes of this behavior. The rolling process will be part of the second aspect. The aim is to show the influence of the parameters on the microstructure and texture and how this could affect the anisotropy in the rolled sheets. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Energy Technology Data Exchange (ETDEWEB)

In order to investigate the extrusion characteristics of magnesium alloy (AZ31), a computer simulation was attempted. Tensile properties of as-cast billet with different strain rates were incorporated into the simulation. The results showed a great change in distribution of stress and strain at near die region by the ram travel. It was found that the average grain size at longitudinal edge of the extruded sheet was smaller than that at center region, which might be attributed to recrystallization caused by severe plastic deformation. (orig.)

Energy Technology Data Exchange (ETDEWEB)

In this paper, the adaptive optics (AO) system at Keck Observatory is characterized. The AO system is described in detail. The physical parameters of the lenslets, CCD and deformable mirror, the calibration procedures and the signal processing algorithms are explained. Results of sky performance tests are presented: the AO system is shown to deliver images with an average Strehl ratio of up to 0.37 at 1.59 {micro}m using a bright guide star. An error budget that is consistent with the observed image quality is presented.

Science.gov (United States)

This paper describes the anelastic strain recovery and the strain hardening of amorphous metals and presents the experimental result that creep deformation is represented by a viscoelastic model consisting of rheological elements. Materials studied were 80Pd--20Si, 80Fe--13P--7C, and 60 Cu--40 Zr. (DLC)

Energy Technology Data Exchange (ETDEWEB)

The creep behaviour of boiler drums of CuNiMo steels depends on the ratio of the alloys, the heat treatment and the processing technology. Reduction in deformability must be expected but, under optimum conditions, this does not lead to a critical material condition. The appropriate material tests are indispensable. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Previous models of fault-propagation folding used kink-band geometries to approximate folding in front of propagating thrusts. However, kink-band kinematics cannot replicate the curved fold surfaces and complex strain patterns innatural and experimental fault-propagation folds, which also occur in front of steeper reverse and normal faults. Fault-propagation fold hinges tighten and converge downward, forming a triangular zone of penetrative deformation focused on the tip of the propagating fault. The downward convergence of deformation in fault-propagation folds can be modeled as triangular shear zones. Trishear, here defined as distributed, strain-compatible shear in a triangular (in profile) shear zone, provides an alternate kinematic model for fault-propagation folds. Trishear is analogous to simple shear in a tabular shear zone except that area balance in a triangular shear zone requires curved displacement oblique to the fault slip ...

CERN Document Server

Heating during frictional sliding is a major component of the energy budget of earthquakes and represents a potential weakening mechanism. It is therefore important to investigate how heat dissipates during sliding on simulated faults. We present results from laboratory friction experiments where a halite (NaCl) slider held under constant load is dragged across a coarse substrate. Surface evolution and frictional resistance are recorded. Heat emission at the sliding surface is monitored using an infra-red camera. We demonstrate a link between plastic deformations of halite and enhanced heating characterized by transient localized heat spots. When sand 'gouge' is added to the interface, heating is more diffuse. Importantly, when strong asperities concentrate deformation, significantly more heat is produced locally. In natural faults such regions could be nucleation patches for melt production and hence potentially initiate weakening during ...

Energy Technology Data Exchange (ETDEWEB)

Polyethylene gas piping is expected to be in service for times on the order of 50 years depending on service conditions. Therefore research research on piping materials and pipes has two principal objectives: (a) developing methods for predicting when a pipe will fail and (b) improving the material for piping. The prediction of long time failure hinges on the development of short time test methods which relate to long time failure. The improvement in the behavior of current materials also hinges on the use of test methods of short duration relative to the anticipated life time of the pipe in service. One of the primary criterion for an acceptable test method is that it produces the same type of failure as is observed after long time failure in service. It has been found that P.E. pipe material fails in a brittle mode after long periods of time. The failure mode is called brittle because there is little microscopic deformation throughout the pipe; however ...

Energy Technology Data Exchange (ETDEWEB)

Sprengel deformity is a congential malformation with usually unilateral elevation and medial rotation of the scapula. An omovertebral bone is generally present. Associated skeletal malformations are frequently present. Though functional impairment is mild, the cosmetic and psycho-social impairment can be considerable. The prognosis of early surgical therapy is good. The presented case also justifies surgical correction in the older child. (orig.) [German] Die Sprengel-Deformitaet ist eine angeborene Fehlbildung mit meist einseitiger Elevation und Medialrotation der Skapula. Meist ist ein Os omovertebrale vorhanden. Assoziierte skelettale Fehlbildungen sind haeufig. Obgleich funktionell wenig einschraenkend, ist die kosmetische und psycho-soziale Beeintraechtigung oft erheblich. Die Prognose der fruehen operativen Therapie ist gut. Der vorliegende Fall ermutigt zur operativen Therapie auch im hoeheren Kindesalter. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Canisters with spent nuclear fuel can obviously not be located within deformation zones as this might jeopardise their long term mechanical stability and thereby constitute a potential hazard to the biosphere. Less apparent, but equally important, is the fact that earthquakes trigger reactivation, slip, of structures some distance from their hypocentres due to, among many other factors, stress redistribution. Fault slip across a deposition hole might damage the isolation capacity of the canister and thereby jeopardise the overall integrity of the barrier system. Therefore, the following question might be posed: What is the distance from a deformation zone beyond which a canister can be safely emplaced? This respect distance cannot be readily computed because, unknown future events aside, there are some complicated aspects that need to be addressed e.g. degree of conservatism, scale, our ability to model ice sheets and earthquakes, etc. In this ...

International Nuclear Information System (INIS)

The plastic flow behavior of a #beta#-titanium alloy (Ti-15% Mo) was investigated over a wide range of temperatures and strain rates covering those conditions where the #omega#-phase forms dynamically. Portevin-Le Chatelier (PLC) effect was observed in this alloy at temperatures between 575 and 775 K at a strain rate of 1.31 x 10"-"4 s"-"1. The serrated flow behavior of this alloy could be suppressed by rendering the matrix #beta#-phase more stable against the #beta# to #omega# transformation. PLC bands formed in this alloy, studied at different levels of magnification using light, scanning electron and transmission electron microscopy, showed a high density of deformation bands within the macroscopic PLC band. The following mechanism of serrated flow is proposed; the load drop is ascribed to the sudden flow associated with the formation of deformation bands within which #omega#-particles were destroyed while the subsequent load rise results ...

International Nuclear Information System (INIS)

For optimizing the microstructure of the (#alpha# + #beta#)-titanium alloy TiAl5Fe2.5 the content of the two alloying elements aluminium and iron in the #alpha#- and #beta#-phase was determined by microprobe analysis. The alloys with the composition of the #alpha#- and of the #beta#-phase at 850 degC TiAl6Fe0.5 (#alpha#-phase) and TiAl3.5Fe6.5 (#beta#-phase) were prepared by arc melting and rolling at 850 degC. The mechanical properties of the '#alpha#'- and of the '#beta#'-phase-alloy are compared with the properties of the (#alpha# + #beta#)-alloy TiAl5Fe2.5 in the as rolled and swaged condition and after an additional aging at 550 degC. By this optimizing process it was possible to achieve a tensile strength of Rsub(m) = 1012 N/mm"2, an yield strength of Rsub(p0.2) 954 N/mm"2 and an elongation at fracture A = 14.5% in the TiAl5Fe2.5-alloy, although the degree of hot deformation was small. By a higher degree of deformation these properties ...

Energy Technology Data Exchange (ETDEWEB)

Differential cross sections for 201.5 MeV proton scattering form /sup 88/Sr were measured. From the analysis of the elastic data, no unique optical-model potential could be obtained, but the radial moments are well determined. In a macroscopic analysis of the collective states it turns out that if the optical potential and transition potential are chosen consistently, unambiguous potential deformation lengths can be obtained even though the optical potential is not unique. Taking into account the range and density dependence of the underlying effective interaction reliable neutron deformation lengths can be obtained. For inelastic transitions of various character microscopic distorted-wave calculations with a density-dependent interaction based on the Paris potential were performed. The nuclear structure was taken from one broken-pair calculations in a large model space, calibrated by (e,e') data. In general a good description is ...

Energy Technology Data Exchange (ETDEWEB)

An axisymmetric unit cell model based on a regular array of second-phase particles arranged on a BCC lattice is used to study deformation mechanisms of ferrite-pearlite structural steels. Microstructural characteristics of the steels were parameterized by the pearlite volume fraction, the aspect ratio of the pearlite particles, and the neighboring factor, which represents the ratio of interparticle spacing in the longitudinal direction to that in the transverse direction. FE analyses were carried out to investigate the macroscopic and microscopic response of unit cells with morphological features based on idealizations of the microstructures of the actual steels. Tensile properties of each constituent phase were obtained experimentally and used in the analyses. As compared to traditional axisymmetric models, the BCC tell model appears to be able to capture more realistically the behavior of the materials, and it accurately estimates the tensile behavior of the ...

International Nuclear Information System (INIS)

Fe-Ni-Mn martensitic steels are one of the major groups of ultra-high strength steels that have good mechanical properties and ductility in as annealed condition but they suffer from severe inter-granular embitterment after aging. In this paper, the effect of heavy shaped cold rolling and wire drawing on the mechanical properties of Fe-Ni-Mn steel was investigated. This process could provide a large strain deformation in this alloy. The total strain was #epsilon# #approx#7. Aging behavior and tensile properties of Fe-10Ni-7Mn were studied after aging at 753 K. The results showed that the ultimate tensile strength and ductility after cold rolling, wire drawing and aging increased up to 2540 MPa and 7.1 %, respectively, while the conventional steels show a premature fracture stress of 830 MPa with about zero ductility after aging.

International Nuclear Information System (INIS)

Laser spectroscopy measurements have been performed on neutron-deficient iridium isotopes. The hyperfine structure and isotope shift of the optical Ir I transition 5d"76s"2 "4F_9_/_2#->#5d"76s6p "6F_1_1_/_2 have been studied for the "1"8"2"-"1"8"9Ir, "1"8"0Ir"m and "1"9"1","1"9"3Ir isotopes. The nuclear magnetic and quadrupole moments were obtained from the hyperfine splitting measurements and the changes of the mean square charge radii from the isotope shift measurements. A large deformation change between "1"8"7Ir and "1"8"6Ir and between "1"8"6Ir"m and "1"8"6Ir"g has been observed.

Energy Technology Data Exchange (ETDEWEB)

The plastic displacements around Knoop indentations made in hard titanium/aluminum multilayered films on soft aluminum alloy substrates have been studied. Indentations were cross-sectioned and imaged using the focused-ion-beam (FIB) milling and high-resolution scanning electron microscopy (SEM), respectively. The FIB milling method has the advantage of removing material in a localized region without producing mechanical damage to the specimen. The micrographs of the cross-sectioned indentations indicate that most of the plastic deformation around the indentation is dominated by the soft aluminum substrate. There is a very small change in the multilayered film thickness around the indentation{emdash}less than 10{percent}. The plastic deformation of the thin film resembles a membrane being deflected by a localized pressure gradient across the membrane. Stress-induced voids are also observed in the multilayered film, especially in the area around ...

Science.gov (United States)

Least-squares analyses were performed on a set of atomic masses using standard and generalized senaiempirical mass laws. Presumably because of errors in the assured form of the standand mass law, its least-squares coefficients can be determined at best to an accuracy of about 10%, and masses are predicted with an uncertainty of several Mev/c/sup 2/. The standard mass law was generalized by addition of shell effect and deformation terms. While the least-squares fitting of the generalized mass law is better than for the standard mass law, it is still not possible to predict atomic masses to an accuracy better than a few Mev/c/sup 2/. The nuclear deformations and the well depth . of the nuclear interaction obtained from the additional mass-law terms are in reasonable agreement with more accurate determinations by other methods. A similar statement applies to the nuclear radius constant as obtained from the ...

Energy Technology Data Exchange (ETDEWEB)

An experimental and computational study was undertaken to estimate the effects of pipe rupture and induced pipe whip impact on surround structures considered either as rigid or deformative such as concrete slabs. This program included sixteen tests using 3 inch schedule 80 (or 10) pipes made of carbon steel similar to A106 grade B. The study consisted of tests on rigid target and on concrete slab. The investigation of whip phase and impact phase was done separately for each test. For pipe impact on rigid targets, the impact forces are found to be directly related to the crush strength of the pipe and the general pipe deformation following the impact. For pipe impact on concrete slabs, the response of the target to the pipe impact needs to take into account the local effect such as penetration and localized damage on the slab. The test matrix covered a broad range of geometric parameters. It provides a significant data base for studying pipe ...

International Nuclear Information System (INIS)

Fretting wear test in room temperature water was performed to evaluate the wear coefficient of CANDU (CANadian Deuterium Uranium) steam generator (SG) tube material (Alloy 800) against 410 type martensitic stainless steels. The main focus is to compare the wear behaviors between Alloy 800 and Inconel 690. Test conditions are 10#approx#30N of normal load, 200#approx#450mm of sliding amplitude and 30Hz of frequency. The result indicated that the wear rate of Alloy 800 was higher than those of Inconel 690 at various test condition such as normal loads, sliding amplitudes etc. From the results of SEM observation, there was little evidence of plastic deformation layer that were dominantly formed on the worn surfaces of Inconel 690. Also, wear particles in Alloy 800 were released from contacting asperities deformed by severe plastic flow during fretting wear. Main cause of wear rate between Alloy 800 and Inconel 690 may be due to the difference of ...

Energy Technology Data Exchange (ETDEWEB)

When the foundations of the building are designed and worked, the prediction calculation of immediate settlement of the building exercised practically is to calculate assuming the earth is a linear elastic body, but the actual stress-strain relationship of the earth is nonlinear and rigidity of the earth becomes lower as strain (or stress) increases. Hence in order to grasp the actual settling behavior of the earth, it is necessary to elucidate the nonlinear relationship between stress and strain. In this article, a prediction method of building settlement is introduced which uses an analytical technique of the multi-layered earth by the linear elasticity theory and takes into consideration strain dependency of rigidity of the earth. Part of the conclusion is as follows which has been obtained by studying the settling behaviors observed in examples of vertical loading tests of the pile foundations and the elasto-plastic settlement analytical method of the pile foundations; the settling ...

Energy Technology Data Exchange (ETDEWEB)

Onshore and marine seismic-reflection data obtained near the Trans-Alaskan Crustal Transect (TACT), in the region of the eastern Aleutian trench and lower Cook Inlet, reveal highly reflective midcrustal layering that begins at a depth of 10-15 km within the upper plate of the Aleutian subduction zone. Beneath the continental shelf, midcrustal reflections were recorded over broad areas and occur in subhorizontal bands that are 1 to 3 s thick. The reflections extend beneath complexly deformed late Mesozoic and early Cenozoic accreted rocks that are exposed at the surface. Preliminary interpretation of seismic refraction data indicates that under the shelf the top of the reflections corresponds in depth with a sharp increase in rock velocity, from 5.9 km/s to 6.6 km/s. North and northwest of the shelf, beneath the Chugach and Kenai mountains, midcrustal features dip 20{degree}-30{degree} north or northwest, and below the Chugach Mountains, the top of the reflections ...

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of analysis of selected data from the NRU test series dealing with heatup and reflood heat transfer during postulated PWR LOCA conditions. These tests used nuclear fuel rods and some considered clad ballooning and rupture. Also included was an electrically-heated rod ballooning test, REBEKA-6. The COBRA-TF computer program, renamed PYTHONS, was modified and used for the analytical tool. Modifications included provisions for fuel rod gas flow and pressure, creep deformation and rupture, channel blockage, and blockage heat transfer. Calculated clad temperatures for NRU unpressurized rods show quite good agreement with experimental data. The calculated amount and axial extent of clad ballooning for pressurized rods agrees reasonably well with post-test examinations of the NRU bundles. Time to failure was underpredicted in the MT-3 test as a result of the high strength of NRU clad material which was not represented in the PYTHONS creep ...

CERN Document Server

The existence of n-particle n-hole deformed yrare bands in the N=28 isotones is explored using full pf-shell diagonalizations and the Lanczos Strength Function method. We find different 2p-2h and 4p-4h collective bands that, when allowed to mix, more often disappear. Only the 2p-2h yrare band in Cr-52 and the 4p-4h yrare band in Ni-56 survive, and only in this latter case, due to the reduced density of 2p-2h states, can the band be seen as a gamma-cascade.

Energy Technology Data Exchange (ETDEWEB)

The 4025/2 bands in [sup 177]Ta which are ''identical'' to the neighboring even-even [sup 176]Hf groundstate band have been extended to higher angular momentum. These bands in the two nuclei are seen to diverge from each other in the region of the first i[sub 13/2] neutron alignment. The lower observed crossing frequency for the 4025/2 bands indicates a lower deformation for these bands compared to [sup 176]Hf. Extensions to the h[sub 9/2] 5411/2 yrast band are also reported. (orig.)

British Library Electronic Table of Contents (United Kingdom)

The shrinkage of the cement paste with low water-cement ratio at different relative humidity was observed and analyzed with ESEM and deformation map technique. The crack morphology was observed with different magnification with SEM and FESEM, and the formation of the crack was observed with AFM between two C-S-H nano particles. The observation by multi technique at multi scale indicated that the shrinkage was increase with the decrease of the humidity due to the increase of the pressure of the capillary pressure, the morphology of the crack in smaller scale was similar to that in the bigger scale, the smaller crack distributed in the latticework of the bigger ones, and the crack propagated along the gap between two nano particles of C-S-H with weaker bonding.

International Nuclear Information System (INIS)

Superplastic deformation behavior in an alpha + beta titanium alloy Ti-3A-4V has been investigated by using the method of cross head speed cycling in the temperature range 750-910 /sup 0/C. On the basis of flow stress-strain rate-strain rate sensitivity data, the alloy was found to be superplastic in the entire temperature range studied. Optimum superplasticity was observed in the strain-rate range 3 x 10/sup -5/ sec./sup -1/ to 6 x 10/sup -5/ and at the highest temperature of 910 deg. C. (author).

International Nuclear Information System (INIS)

The mixed structure of a nuclear reactor building is composed of SC-columns, S-beams, S-joints and PCa-panels. Following the last report (Part 7)[1], the main test results of the mixed structure, that is, the deformation mode, strain distribution and shear strength, are described. The S-joints using ultrahigh strength materials had no buckling nor shear slipping. The proposed mixed structure resisted the external horizontal forces under integrated uniformity among SC-columns, S-joints and PCa-panels. It could be confirmed that the mixed structure can be established. (author)

International Nuclear Information System (INIS)

Muonic-atom energy levels and wave functions are calculated. The results are corrected for nearly all important static effects, including finite nuclear size as produced by a user-specified nuclear charge distribution. Fourth-order Runge-Kutta integration of the radial Dirac equations, with the secant method determining the eigenvalues. Corrections are either included as potentials in the Dirac equations or computed as first-order perturbations. The code assumes spherical symmetry, so that effects of nuclear deformation may be treated only as static first-order perturbations. Dynamic muon-electron and muon-nuclear effects are neglected (the latter are calculated by RURP). (Auth.).

International Nuclear Information System (INIS)

We demonstrate reversible movement of (1/2)[110](110) dislocation loops generated from nanodisturbances in a #beta#-titanium alloy. High resolution transmission electron microscope observations during an in situ tensile test found three reversible deformation mechanisms, nanodisturbances, dislocation loops and martensitic transformation, that are triggered in turn with increasing applied stress. All three mechanisms contribute to the nonlinear elasticity of the alloy. The experiments also revealed the evolution of the dislocation loops to disclination dipoles that cause severe local lattice rotations.

Energy Technology Data Exchange (ETDEWEB)

Results are given for deep-level petroleum and gas drilling probes in various coastal zones of Southern Sakhalin covering the Poronai depression and the Aniv Bay trough. The exploratory probes indicate that the Middle Miocence deposits of the Boundary trough contain commercial-size deposits of petroleum, that commercial-size gas deposits are in the upper Myocene deposits of the Aliv Bay trough, and that the upper Cretaceous and Cenozoic deposits of the eastern section of Southern Sakhalin lack folded deformations. 7 references, 2 figures.

CERN Document Server

We propose a new approach to study Koszul cohomology of general $g^r_d$'s on general curves via degenerations and deformations. As an application of this new method, we prove projective normality for general line bundles $L$ on general curves with $h^1(L)\\le1$ and degree greater than roughly $(5/4)g$. This improves the bound in a classical theorem of Green and Lazarsfeld. Also we give some partial results on vanishing of higher syzygies for line bundles with $h^1(L)=1$.

International Nuclear Information System (INIS)

Energy level schemes are derived from gamma spectroscopy of several medium-mass deformed nuclei by studying the decay or proton and #alpha# nuclear spectroscopic data. Some new isomeric studies are established among which is the 31 y "1"7"8Hf isomeric state for which Isup(#pi#), K was determined to be 16"+, 16. A four quasi-particle configuration was assigned to this state at 2447.5 +- 2.5 KeV. Atomic masses have been calculated from various measurements and, on the basis of mass formulae extrapolated to neighboring mass regions.

Energy Technology Data Exchange (ETDEWEB)

The grain boundary crystallographic misorientations of magnetic-pulse-welded (MPW) aluminum alloy (AA) 6061-T6 in linear and tubular configurations were examined using the electron backscattered diffraction (EBSD) technique. A refined structure of heavily deformed grains with higher grain boundary angles was observed in linear welds. Significant spalling was observed away from the joints, in the interior of tubular welds. The results show the complex interaction of shock waves with the materials during this impact welding process.

British Library Electronic Table of Contents (United Kingdom)

The effect of elastic and plastic strains on the magnetic properties of ferrite-pearlite steels has been studied. It has been shown that the sensitivity to elastic-tensile and bending strains is four to five times greater for remnant magnetization than for coercive force. In order to determine the degree of cold plastic deformation of high-carbon steels, a two-parametric testing technique based on the use of remnant magnetization and coercive force was suggested. An MMT-2 device was recommended for measurement of the required parameters.

International Nuclear Information System (INIS)

Based on the single-particle levels given by Nilsson, the intrinsic and effective (with collective effects) level density parameters as a function of the excitation energy for the "1"8"6Os, "1'8"7Ir, "1"8"9Os and "1"9"3Au deformation nuclei have been calculated in the range of the excitation energy up to 150 MeV. The calculated fission probabilities P_f (U) are consistent satisfactorily with the experimental data when a nonadiabatic estimation of the collective effects was used to calculated the nuclear level density parameters.

British Library Electronic Table of Contents (United Kingdom)

Epitaxial thin films of nanotwinned face-centered cubic metals such as Cu possess an unprecedented combination of high hardness and high electrical conductivity due to the unique structure of nanometer-spaced coherent twin boundaries. Recent studies of in-situ nanoindentation in a transmission electron microscope have provided new insights on the deformation behavior of nanotwins that are reviewed here. In particular, two unit processes are highlighted: first, stress-induced migration of ?3 {112} incoherent twin boundary that leads to de-twinning of nanotwins; second, twinning dislocation can be multiplied at ?3 {111} coherent twin boundary.

British Library Electronic Table of Contents (United Kingdom)

The Rosebel gold district is hosted in a Paleoproterozoic greenstone belt of the Guiana Shield and has many characteristics that enable classification of the ores as an orogenic gold deposit. Host rocks have undergone several phases of deformation. However, gold deposition occurred late in the structural history of the belt, and is considered part of a late regional metallogenic event with respect to the geotectonic evolution of the Guiana Shield. Economic gold mineralization is hosted in felsic to mafic volcanic rocks and two sedimentary successions that are differentiated into turbiditic and arenitic depositional packages. The detailed lithostratigraphic characterization and the geochemistry enable the correlation of the local rock types with the Paramaka, the Armina, and the Rosebel for...

Energy Technology Data Exchange (ETDEWEB)

In the tests, the effects of the overhang length on the pipe whip behavior of the pipe-restraints system were studied by measuring the strains and deformations of the test pipe and restraints, and the restraints forces. The equation for predicting the maximum strain at the outer surface of the pipe was derived using a static equilibrium condition. The calculated maximum strains at the outer surface of the pipe agree fairly well with experimental data. The dynamic response analysis of the pipe-restraints system was conducted by the finite element program ADINA. The applicability of the ADINA program to the pipe whip analysis is made clear through this analysis.

Energy Technology Data Exchange (ETDEWEB)

To evaluate the effect of porosity on superplasticity behavior, it is essential to use materials of similar initial grain sizes. This can be achieved by HIPing, which provides an effective way of reducing initial porosity while avoiding appreciable grain growth; various levels of porosity can be achieved for similar grain sizes. This note is concerned with the influence of porosity on superplasticity tensile deformation of a fine grained high-purity alumina doped with copper oxide and containing a grain growth inhibitor. Specimens were prepared by slip casting to net-shape and sintering; some presintered specimens were HIPed to reduce porosity. The subsequent superplasticity behavior is related to porosity in the material.

Energy Technology Data Exchange (ETDEWEB)

Evaluates displacement of a railway bridge element of the Walbrzych-Klodzko railway line. The bridge, consisting of three truss sections supported by two pillars made of reinforced concrete, was influenced by longwall mining. Longwalls were perpendicular to the bridge axis. Three coal seams situated in the bridge safety pillar were 550 cm thick. Ground subsidence after seam extraction was 400 cm. Ground subsidence did not cause truss section deformation, nor did it cause additional stresses in truss bridge construction. 2 refs.

International Nuclear Information System (INIS)

Heyuan mineralization belt is a structure-magmatic activities belt which is charcterized by strong plastic deformation and shearing. The squeeze (overthrust) structure is formed early. Later stretch produced slide shovel-shaped normal fault which control the red basin and uranium mineralization. Comprehensive study shows that this area is of favorable uranium metallogenic condition due to the rich uranium source and higher degree of geology work, it is a target for the new round resources exploration. (authors)

Energy Technology Data Exchange (ETDEWEB)

We report here the imaging findings of a rare case of a lethal form of Gorham disease in a young female patient. Multimodality imaging findings over 13 year-follow-up demonstrated progressive wide spread skeletal and soft tissue abnormalities with permeative osteolysis, pathological fractures and severe skeletal deformities. Unusual extensive osseous and soft tissue pneumatosis was illustrated on cross-sectional studies. The progressive nature of this form of Gorham disease and the subsequent complications eventually culminated in patient's death. (orig.)

CERN Document Server

Based on Friedberg and Lee's geometric picture by which the tribimaximal PMNS leptonic mixing matrix is constructed, namely corresponding mixing angles correspond to the geometric angles among the sides of a cube. We suggest that the three realistic mixing angles which slightly deviate from the values determined for the cube, are due to a viable deformation from the perfectly cubic shape. Taking the best fitted results of $\\theta_{12}$ and $\\theta_{23}$ as inputs, we determine the central value of $\\sin^22\\theta_{13}$ should be 0.0238 with a relatively large error tolerance, this value lies in the range of measurement precision of the Daya Bay experiment.

International Nuclear Information System (INIS)

The International Atomic Energy Agency has initiated a co-ordinated research programme on implementation of base-isolation for nuclear structures. This paper discusses two areas relevant to modelling elastomeric base-isolators. These are the use of simplified models to predict the response of isolated structures to earthquake inputs and finite element analysis for calculating the stress distributions within the isolators. In the former, a curvilinear hysteretic model of the high damping natural rubber able to accommodate the stiffening of the rubber at large shear deflections is presented. Its predictions of structural accelerations and bearing displacement produced by design earthquakes and those above the design level are compared with those using a linear spring and dashpot model. A comparison has been made between two finite element analyses using MARC and ABAQUS of the force-deformation behaviour of a single disc of rubber bonded on both sides. The disc was ...

Science.gov (United States)

It is well known that one of the main advantages of the high speed forming (HSF) processes is the improvement in the forming limits of the used materials.Using the Electromagnetic Forming (EMF) technology two materials have been tested with different mechanical and physical properties: the AA5754 aluminium and the AZ31B magnesium alloys.The EMF process principle can be described as follows: A significant amount of electrical energy is stored in a bank of capacitors which are suddenly discharged releasing all the stored energy. This electric discharge runs through a coil which generates an intense transient magnetic field. At the same time transient Eddy currents are induced in the electrically conductive part placed some millimetres far from the coil. Another intense magnetic field is generated due to those Eddy currents but on the opposite direction as the one generated by the coil. A big magnetic repulsion force is created between the part and the coil. This magnetic repulsion ...

International Nuclear Information System (INIS)

A distinguishing design feature of CANDU nuclear reactors is the use of horizontal fuel channels housed in a horizontal vessel called a calandria, which is made of stainless steel 304L. Each channel consists of a Zr-2.5%Nb alloy pressure tube and an externally concentric Zr-2 calandria tube. The calandria tubes are joined to the end plates (tubesheets) of the calandria vessel by joints formed by roller expansion. The bores in the tubesheets are grooved. Roller expanded joints provide a cost effective means of joining dissimilar materials, require minimal space and no maintenance. The quality of these roller expanded joints is important from a sealing, strength and stress corrosion point of view. The roller expansion process consists of expanding the calandria tubes to deform them plastically against the bores and into the grooves of the tubesheets. Therefore, understanding the effect of the number, geometry and the pitch of the grooves on the quality of a roller ...

Energy Technology Data Exchange (ETDEWEB)

The effect of severe plastic deformation by cold high pressure torsion (HPT) on radio frequency (RF) plasma nitriding of pure iron, as well as St2K50 and X5CrNi1810 steels was investigated. Nitriding was carried out for 3 h in a nitrogen atmosphere at a pressure of 10{sup -5} bar and temperatures of 350 and 400 deg. C. Nitrided specimens were analysed by scanning electron microscopy (SEM), X-ray diffraction and micro hardness measurements. It was found that HPT enhances the effect of nitriding leading almost to doubling of the thickness of the nitrided layer for pure iron and the high alloyed steel. The largest increase in hardness was observed when HPT was combined with RF plasma nitriding at 350 deg. C. In the case of pure iron, the X-ray diffraction spectra showed the formation of {epsilon} and {gamma}' nitrides in the compound layer, with a preferential formation of {gamma}' at the expense of the {alpha}-phase at the higher nitriding ...

British Library Electronic Table of Contents (United Kingdom)

The gravitational torque applied on the Earth by the other celestial bodies generates periodic variations in the orientation of the Earth's rotation axis in space which are called nutations. Observations of Earth's nutations allow for insights into the physical properties of the inner core because of the presence of a normal mode, the Free Inner Core Nutation (FICN), which is characterized by a tilt of the inner core figure and rotation axes with respect to the mantle and outer core. The frequency of the FICN is controlled by the strength of the mechanical coupling acting at the inner core boundary (ICB) and by the ability of the inner core to deform under the action of centrifugal and gravitational forces. Attenuation of the FICN reflects energy dissipated by electromagnetic (EM) and visc...

Energy Technology Data Exchange (ETDEWEB)

We develop the formalism of a unified semi-microscopic description of low-energy proton and {alpha}-particle interaction with nuclei. We analyze elastic and inelastic proton scattering at the energy 25.05 MeV and {alpha}-particle scattering at the energy 104 MeV by the {sup 90}Zr nucleus. Information is obtained on differences in the deformation of the proton and neutron distributions. We study the energy dependence of the semi-microscopic {alpha}-particle potential including the energy dependence of the potential geometry.'' We analyze the change in angular distributions of elastically scattered {alpha} particles with increase of energy and the contribution to the scattering cross section from nucleon-nucleon correlations.

Energy Technology Data Exchange (ETDEWEB)

Generation of anomalous resistivity and dynamical development of collisionless reconnection in the vicinity of a magnetically neutral sheet are investigated by means of a three-dimensional particle simulation. For no external driving source, two different types of plasma instabilities are excited in the current layer. The lower hybrid drift instability (LHDI) is observed to grow in the periphery of current layer in an early period, while a drift kink instability (DKI) is triggered at the neutral sheet in a late period as a result of the nonlinear deformation of the current sheet by the LHDI. A reconnection electric field grows at the neutral sheet in accordance with the excitation of the DKI. When an external driving field exists, the convective electric field penetrates into the current layer through the particle kinetic effect and collisionless reconnection is triggered by the convective electric field earlier than the DKI is excited. It is also found that the ...

Energy Technology Data Exchange (ETDEWEB)

Extruded and hot-rolled 200 C {proportional_to} 500 C AZ31B plates were studied their texture using ODFs analysis. The as-extruded specimen has the strongest intensity of (0001)-ND fiber and 300 C and 400 C hot-rolled ones have the next, but the 200 C hot-rolled one has the lowest intensity. Compared with the corresponding tensile properties, this feature evidents that a pronounced (0001) basal texture will reduce ductility of AZ31B alloy. The ODFs results also indicate that (05 anti 52)- and (01 anti 10)-ND fibers are related to the ductility of AZ31B alloy. (orig.)

British Library Electronic Table of Contents (United Kingdom)

A wide area of the Assisi town, in Umbria (central Italy), is interested since its first edification (1950?1960) by an extensive landslide. The rate of motion is very slow (around 1?cm/year), but the deformations accumulated for almost 60?years have produced considerable damage to many private and public buildings, including the civic hospital and an important Franciscan monastery. The University of Perugia established in 1995 a geodetic monitoring network over the Assisi landslide, connecting a number of control points inside the moving area to an external reference network with markers placed on stable geological formations. The monitoring has been based since the beginning on GPS satellite positioning with static observations, aiming to obtain a three-dimensional accuracy of about 1?cm ...

Science.gov (United States)

Raytheon's Santa Barbara Remote Sensing (SBRS) division designed and built the MTSAT-1R Japanese Advanced Meteorological Imager for the Japanese Ministry of Transport between March, 1999 and July, 2002. In order to meet the stressing requirements of a geosynchronous orbit, a combination of structural, thermal, and optical (STOP) analyses were used to design and optimize the beryllium three-mirror anastigmat (TMA) telescope. This modeling approach was used to characterize and minimize the thermal distortion around local midnight. On-orbit temperatures and structural deformations were predicted using thermal Desktop/SINDA and PATRAN/NASTRAN software, respectively. The resulting optical performance was evaluated using Raytheon developed HEXAGON software. The telescope design was successfully optimized to attain specified visible channel performance for most of the 24 hour orbit.

Energy Technology Data Exchange (ETDEWEB)

Most of previous study for creep rupture of RPV lower head under severe accident condition, have been focused on global failure of RPV lower head. In contract, the local failure of the RPV nozzle region has not been studied in detail. The existence and features of nozzle failure in LAVA-ICI specimen of KAERI and LHF-4 specimen of Sandia National Lab., are observed. It is confirmed that the nozzle failure of LHF-4 specimen is due to the hoop stress in the RPV. The tensile tests in various temperatures and the creep rupture tests in various temperatures and stresses, are accomplished. The finite element analysis for LAVA-ICI experiment was confirmed, and the stress and deformation analysis results are used in LAVA-ICI experiment. 17 refs., 34 figs., 3 tabs. (Author)

International Nuclear Information System (INIS)

By means of the light microscopy and by the measurement of the mechanical properties one investigated into the phase composition and the properties of Al-Mg-Ce and Al-Mg-Y system alloys. One plotted the isothermal cross sections of the mentioned systems under 430 and 275 deg C temperatures at up to 16% magnesium concentration and up to 0.7% yttrium concentration. One determined the yield limit and strength, the relative elongation of Al-Mg base hardened and deformed alloys containing 7.0-9.9% Mg and Ce, Y, Mn, Zr dopes upon ageing under 175, 200, 250 and 300 deg C temperatures within the ageing time ensuring the hardening maximum effect

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Natural fractures and in situ stresses commonly dictate subsurface reservoir permeability and permeability anisotropy, as well as the effectiveness of stimulation techniques in low-permeability, natural gas reservoirs. This paper offers an initial prediction for the orientations of the fracture and stress systems in the tight gas reservoirs of the Frontier Formation, in the Green River basin of southwestern Wyoming. It builds on a previous report that addressed fractures and stresses in the western part of the basin and on ideas developed for the rest of the basin, using the principle that thrust faults are capable of affecting the stress magnitudes and orientations in little-deformed strata several hundreds of kilometers in front of a thrust. The prediction of subsurface stresses and natural fracture orientations is an undertaking that requires the willingness to revise models as definitive data are acquired during drilling. The predictions made in this paper are ...

International Nuclear Information System (INIS)

The purpose of this experimental study is to investigate the micromechanical fatigue behavior, in terms of slip nature and preferential cracking sites, of a commercial #alpha#/#beta#-forged Ti-6Al-4V alloy. Electron backscattering diffraction is extensively used to identify the deformation (prismatic, basal, pyramidal slip) and crack formation modes activated by fatigue at the surface of several hundred primary #alpha# nodules. Some fatal crack formation sites are also characterized. Cracking in basal planes is identified as the most critical damage mode leading to fracture. An explanation is proposed which involves the resolved shear stress, taking into account the Schmid factor and the normal stress in relation to the elastic anisotropy of the #alpha#-phase. Finally, the spatial distribution of the secondary cracks is analyzed according to the crystallographic textures (macrozones) present on a mesoscopic scale in the Ti-6Al-4V alloy.

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Elastic and inelastic proton scattering has been measured in inverse kinematics on the unstable nucleus {sup 40}S. A phenomenological DWBA analysis yields a quadrupole deformation parameter {beta}{sub 2} = 0.35 {+-} 0.05 for the 2{sup +}{sub 1} state. Consistent phenomenological and microscopic proton scattering analyses have been applied to all even-even Sulfur isotopes from A = 32 to A = 40. The microscopic analysis used microscopic collective model densities and a modified Jeukenne-Lejeune-Mahaux effective interaction. This analysis suggests the presence of a neutron skin in the heavy sulfur isotopes. The analysis is consistent with normalization values for {lambda}{sub {upsilon}} and {lambda}{sub {omega}} of 0.95 for both the real and imaginary parts of the JLM potential. (author)

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The pressure dependence of the photoluminescence (PL) transition associated with the fundamental band gap of ZnO nanowires has been studied at pressures up to 15 GPa. ZnO nanowires are found to have a higher structural phase transition pressure around 12 GPa as compared to 9.0 GPa for bulk ZnO. The pressure-induced energy shift of the near band-edge luminescence emission yields a linear pressure coefficient of 29.6 meV/GPa with a small sublinear term of -0.43 meV/GPa{sup 2}. An effective hydrostatic deformation potential -3.97 eV for the direct band gap of the ZnO nanowires is derived from the result.

Energy Technology Data Exchange (ETDEWEB)

Two approaches are used to analyse X-ray or neutron scattering by crystals with different dislocation ensembles. Analogy between the above concepts is discussed. The microscopical approach takes into account the detailed displacement field due to different types of dislocation arrangement in the crystal. Frequently a phenomenological concept operating with the ideas of displacements, strains and stresses arising in the materials under deformation is applied. Unfortunately, the phenomenological concept cannot take into account that similar stress distributions may have significantly different microscopic reasons. The comparison of the results obtained by both phenomenological and microscopic descriptions of scattering enables us to understand the connection between different types of strains and stresses in the crystal with the type of the defects in it. (orig.)

British Library Electronic Table of Contents (United Kingdom)

SUMMARY We construct a new class of granular landslide models in which avalanches are simulated with large numbers of independent particles moving under the influence of topographically derived gravitational and centripetal acceleration. Concurrently, the particles suffer deceleration due to basal and dynamic friction. The novel aspect of the calculation is that complex particle-to-particle interactions, fluctuating basal contacts, and unresolved topographic roughness within and below the deforming flow are mimicked by random perturbations in along-track and cross-slope acceleration. We apply the method to the 1980 May 18 Mount Saint Helens debris avalanche by constraining the initial geometry and structure of the slide mass from geological data, and the initial failure sequence from eyewi...

International Nuclear Information System (INIS)

Differential cross sections for the excitation of the first octupole-vibrational state in the closed-neutron-shell nuclides "8"8Sr and "9"0Zr and in the closed-proton shell-nuclei sup(116,118,120,124)Sn by 11 MeV neutrons are presented. The distorted-wave Born approximation is used to obtain deformation lengths, delta(3"-) for each state. Results are compared with earlier measurements of inelastic proton scattering to the same states. Although limited resolution in the neutron time-of-flight spectrometer complicates the interpretation of the Sn data, the overall conclusion that deltasub(nn')(3"-) approx. deltasub(pp')(3"-) is supported by all of the measurements. (orig.).

Science.gov (United States)

The systematic behavior of excited nuclear levels was studied with Lu (Z = 71), Ta (Z = 73), and Re (Z = 75) activities produced in the ORNL proton cyclotron. Conversion-electron data are presented for electron-capture decay of Lu/sup 170.174m/, Ta/sup 173-178/, and Re/sup 179.181/. Level schemes are proposed based on these and on previously published up 173.175-179/, tulated. The proper ties of odd-A nuclei in the strongly deformed region of odd-N numbers 95-107 are discussed in connection with predictions of Mottelson and Nilsson. Two activities, Lu/sup 174m/ and Re/sup 179/ ( es sufficiert t 20 min), are previously unreported. (auth)

Energy Technology Data Exchange (ETDEWEB)

An experimental capability, developed at Lawrence Livermore National Laboratory (LLNL), is being used to study the yield behavior of elastic-plastic materials. The objective of our research is to develop better constitutive equations for polycrystalline metals. We are experimentally determining the multidimensional yield surface of the material, both in its initial state and as it evolves during large inelastic deformations. These experiments provide a more complete picture of material behavior than can be obtained from traditional uniaxial tests. Experimental results show that actual material response can differ significantly from that predicted by simple idealized models. These results are being used to develop improved constitutive models of anisotropic plasticity for use in continuum computer codes.

Energy Technology Data Exchange (ETDEWEB)

Mechanical alloying is an important pre-requisite for the manufacturing of heat resistant oxide-dispersion-strengthened superalloys. Though the microstructure of these materials after hot extrusion and recrystallization treatment is well documented, little is known about the microstructural evolution during ball-milling. A method was tested to prepare electron transparent foils and extraction replica from powder particles for TEM investigations. The microstructure was found to consist of a Ni-Cr-Al solid solution in which submicron particles of refractory metals were embedded. The extremely fine grainize of about 50 nm is the consequence of severe plastic deformation. Yttria particles could not be detected in the powder after ball milling, but after a heat treatment at 1000 C the well-known fine dispersion of oxide particles was evident. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The microstructural evolution of a AZ31 Mg alloy during hot rolling has been investigated using optical microscopy and texture (macro and micro) analysis as the main characterization tools. In particular, the differences between the microstructure obtained by unidirectional rolling (UR) and cross rolling (CR) are studied. Significant twinning activity is observed in both cases. Additionally, after cross rolling, a rather heterogeneous microstructure develops, with scattered regions populated by very fine grains. The strong basal fiber texture of the as-received material remains present after both hot rolling schemes. The impossibility to obtain accurate EBSD measurements within the twinned regions suggests that significant localized deformation takes place in those areas. Thus, these regions become preferential sites for the onset of recrystallization due to the increase in the local strain energy. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The strongly localized one-electron (D{sup 0}) and two-electron (D{sup -}) donor states are considered with the lattice deformation around the donor center taken into account. For GaAs, donor energy levels have been calculated as functions of the hydrostatic pressure. The calculated energy positions and pressure coefficients agree with the experimental data. It is shown that the interaction with phonons reduces the probability of radiative transitions between the states of different localization and leads to the metastability of shallow-level donor states with respect to the D{sup -} state in GaAs and both the states (D{sup 0} and D{sup -}) in CdF{sub 2}. (author) 7 refs, 1 fig

CERN Document Server

Numerical simulations are used to test the kinetic theory constitutive relations of inertial granular shear flow. These predictions are shown to be accurate in the dilute regime, where only binary collisions are relevant, but underestimate the measured value in the dense regime, where force networks of size $\\xi$ are present. The discrepancy in the dense regime is due to non-collisional forces that we measure directly in our simulations and arise from elastic deformations of the force networks. We model the non-collisional stress by summing over all paths that elastic waves travel through force networks. This results in an analytical theory that successfully predicts the stress tensor over the entire inertial regime without any adjustable parameters.

Energy Technology Data Exchange (ETDEWEB)

In CsCdBr{sub 3}, Tm{sup 3+} substitutes for Cd{sup 2+}. It predominately forms symmetric dimer centers and single-ion centers, both of trigonal symmetry. The energy level schemes of both centers were determined by EPR and site-selective laser spectroscopy. To describe the spectra term dependent crystal-field parameters were deduced on the basis of a microscopic model taking into account the local lattice deformation induced by the impurity centers and the quasi-resonant virtual scattering of intrinsic lattice excitations by the Tm{sup 3+} ions. (orig.) 22 refs.

International Nuclear Information System (INIS)

Denting phenomenon as experienced in PWR steam generators has been investigated in the laboratory of Monel-400 tubes and C-steel baffles combination. Isothermal corrosion tests have been carried out by exposing capsules, containing a crevice between Monel-400 tubes and C-steel plugs, in plausible corrodents at 300"0C. Results indicated that the denting phenomenon is strongly influenced by the chloride content in the solution. In addition, it is a time dependent process. Stress exerted on the tubes by the growth of corrosion product on the outside surface of C-steel plugs are enough to deform the Monel tubes. The results have been discussed on the basis of accelerated corrosion of C-steel by hydrolyzable metal chlorides. (author).

Energy Technology Data Exchange (ETDEWEB)

Dynamic development of new grain boundaries was studied in compression of a magnesium alloy AZ31 with initial grain sizes (D{sub 0}) of 22 {mu}m and 90 {mu}m at a temperature of 673 K. Kink bands are evolved near corrugated grain boundaries and in grain interiors at low strains accompanied with new fine grains. Kink bands are developed often perpendicular to the basal plane. The boundary misorientation of kink band as well as the volume fraction of new grains increases rapidly with increasing strain and approaches a saturation value in high strain. New fine grains are developed faster with decrease in the D{sub 0}. It is concluded that new grain evolution is controlled by a deformation-induced continuous reaction, i.e. continuous dynamic recrystallization (DRX). (orig.)

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The radiographs and initial clinical findings of 73 patients who had sustained trauma to the cervical spine without bony injury in vehicle collisions were reviewed. The patients were also re-examined clinically two years after the injury. Forty eight (65.8%) had abnormal radiographs at presentation - prevertebral soft tissue swelling in 15 (20.6%), degenerative changes in 15 (20.6%), and an angular deformity between two adjacent vertebral bodies in 27 (37.0%). The exact mode of inury is not associated with any specific radiographic appearance except that ''roll overs'' and side collisions are more likely to cause angulation in the cervical spine. (orig./GDG).

International Nuclear Information System (INIS)

The powder particle size, D, influences the creep behaviour of Al-Cr-Zr alloys. The alloy studied in this work, Al-5Cr-2Zr (mass%), was prepared by argon atomization. Three size fractions of powder particles were selected: 24-50 #mu#m, 50-100#mu#m and 100-200 #mu#m in diameter. They were consolidated by extrusion. Independently of D, the flow behaviour of the alloy can be described by the power law equation. As test temperature increases, the stress exponent n decreases up to a value close to 5. A decrease of D causes an increase of n and delays the alloy degradation at high temperature. (Author) 11 refs.

CERN Document Server

The nucleation and propagation of hydrofractures by injection of over pressured fluids in an elastic and isotropic medium are studied experimentally. Non-Newtonian fluids are injected inside a gelatine whose mechanical properties are assumed isotropic at the experimental strain rates. Linear elastic theory predicts that plastic deformation associated to breakage of gelatin bonds is limited to a small zone ahead of the tip of the propagating fracture and that propagation will be maintained while the fluid pressure exceeds the normal stress to the fracture walls (Ch\\'avez-\\'Alvarez,2008) (i.e., the minimum compressive stress), resulting in a single mode I fracture geometry. However, we observed the propagation of fractures type II and III as well as nucleation of secondary fractures, with oblique to perpendicular trajectories with respect to the initial fracture. In the Video (http://hdl.handle.net/1813/14122) experimental evidence shows that the fracture shape ...

Energy Technology Data Exchange (ETDEWEB)

The conference proceedings contains 30 papers of which five are abstracted separately. The subjects covered include fatigue crack growth in aircraft materials, fractographic measurements, fatigue cracks in nylon 66 blends, cyclic inelastic deformation aspects, prestressing, tensile cracks in creeping solids, creep-crack-growth in 304 stainless steel, high-temperature fatigue, parallel impact loading, numerical fracture dynamic code, J-resistance curves, specimen geometry effects, reactor piping systems, temperature dependence of fracture toughness, small-scale yielding, compact specimens, power hardening materials, semi-empirical fracture analyses, pipeline girth welds, wrought steels, and A36 bridge steels.

International Nuclear Information System (INIS)

The experimental study of the proton-rich nuclei close to the N=Z line is a constant challenge for nuclear spectroscopy, mainly due to the difficulty to produce them with the currently available beam/target combinations. Significant advances on this direction were obtained from experiments performed with the GASP array during the last two years: the yrast line of "8"4Mo was extended up to 10"+, "8"8Ru observed for the first time, and the N=Z+1 line was mapped from "8"1Zr to "9"5Ag. These new results allow us to have a more complete image of the transition from the well-deformed shell closure at N,Z=40 to the spherical-shell closure at N,Z=50, and highlights some particular effects that can be observed only in the vicinity of the N=Z line. (orig.)

International Nuclear Information System (INIS)

The antisymmetric many-body trial state which describes a system of interacting fermions is parametrized in terms of localized wave packets. The equations of motion are derived from the time-dependent quantum variational principle. The resulting fermionic molecular dynamics (FMD) equations include a wide range of semi-quantal to classical physics extending from deformed Hartree-Fock theory to newtonian molecular dynamics. Conservation laws are discussed in connection with the choice of the trial state. The model is applied to heavy-ion collisions with which its basic features are illustrated. The results show a great variety of phenomena including deeply inelastic collisions, fusion, incomplete fusion, fragmentation, neck emission, promptly emitted nucleons and evaporation. ((orig.)).

Science.gov (United States)

A method for determining the critical debond size between the facesheet and the core in composite sandwich panels under in-plane compression is described. The approach uses fracture mechanics together with a buckling criterion for a debonded faceskin. The technique yields predictions for the critical in-plane compressive load for debond propagation as a function of core-to-faceskin debond size, faceskin thickness, lay-up, composite material properties, and honeycomb properties and geometry. A computer program, developed in this work, calculates the critical buckling load and facesheet deformed shape by solving an eigenvalue problem. The output predicts, for several cases, critical initial debond lengths comparable to those that have been observed on tests on sandwich panels.

Energy Technology Data Exchange (ETDEWEB)

Arc distortion can lead to the measuring signal deformation and, consequently, to the erroneous identification or localisation of the fault. In the paper, a study on the short circuit loop resistance and reactance is presented referring to the algorithms using correlation between the sine and cosine functions as well as the least-square method (LSM). In the study, both the static and the dynamic models of the short circuit arc have been employed. The very advantageous features of the LSM-based algorithm have been underlined regarding accuracy of estimation of the short circuit mesh parameters (including the arc voltage at the location where the fault occurs) as well as susceptibility to the presence of a non-periodic short circuit current component. (Author)

Energy Technology Data Exchange (ETDEWEB)

The mass asymmetry of fragments from nuclear fission of heavy nuclei is reviewed. While mass asymmetry is a common and well-known phenomenon for low-energy fission of the lighter actinides, more recent experiments have demonstrated that, for the heaviest actinides, the mass distribution switches to a symmetric one. On the other hand, it has been discovered that, though for fissioning nuclei with mass numbers A< or [approx]225 the mass distribution is basically symmetric, an asymmetric component is clearly to be identified for nuclei down to the Pb-region. In the absence of a generally accepted dynamical theory of fission, the above experimental findings are discussed in terms of static energy considerations. Triggered from the outset by the structure of the potential energy surface at the saddlepoint, the energy balance at the scission point between the available energy (Q-value) of the reaction and the Coulomb and deformation energy of the nascent fragments is ...

Energy Technology Data Exchange (ETDEWEB)

Accidents of free-rolling cars against walls with friction are special cases of the general problem of the dynamic behavior (elastic or plastic) of car motion. Using particle modeling of the car body it is shown that large rotations, contact friction and plastic deformations can be computed. Because of the limitations of FEM it is necessary to model the car as a system of mass points connected by central force systems which are non-linear. The wall is formulated as a rigid body producing constraints for the contacting particles, while the contact force is given by the defined force system. Every contacting particle produces a plastic impact on the wall. The friction force is proportional to the contact force and lies in the direction of the sliding velocity on the wall. Time integration is carried out using a second order Gear method. ((orig.))