Interstitial-mediated diffusion and clustering for transmutation elements Re and Os precipitation in W

Science.gov (United States)

Zhou, Hong-Bo; Li, Yu-Hao; Lu, Guang-Hong

Under high energy (14 eV) neutrons irradiation in nuclear fusion devoices, tungsten (W) will undergo transmutation to its near-neighbors in the periodic table, such as rhenium (Re), osmium (Os), etc. The transmutation elements Re and Os will precipitate and form new Re/Os-rich phase, and further significantly degrade the mechanical properties of W. Here, we have investigated the mechanism for the irradiation-induced Re/Os clustering in W using the first-principles method and thermodynamic models. It is found that there is strong attraction between Re/Os and self-interstitial atom (SIA) in W. The SIA can be easily trapped by Re/Os once overcoming a low energy barrier, and form W-Re/Os complex dumbbell. The diffusion energy barrier of W-Re/Os is much lower than that of Re/Os diffusing via mono-vacancy or even vacancy clusters. Further, the W-Re/Os can be easily trapped by the substitutional Re/Os atoms, and form high stable Re-Re/Os-Os dumbbell structure. Most importantly, the Re-Re/Os-Os dumbbell can serve as trapping centre for subsequent interstitial-Re/Os, leading to the growth of Re/Os-rich clusters in W. Our finding suggests an interstitial-mediated mechanism for the irradiation-induced Re/Os clustering in W. This research is supported by the National Magnetic Confinement Fusion Program with Grant No. 2013GB109002, and the National Natural Science Foundation of China with Grant No. 11675011.

Formation of Frenkel pairs and diffusion of self-interstitial in Si under normal and hydrostatic pressure: Quantumchemical simulation

International Nuclear Information System (INIS)

Gusakov, Vasilii; Belko, Victor; Dorozhkin, Nikolai

2009-01-01

A theoretical modeling of the formation of Frenkel pairs and the diffusion of a self-interstitial atom in silicon crystals at normal and high (hydrostatic) pressures has been performed using quantum-chemical (NDDO-PM5), methods. It is shown that, in a silicon crystal, the most stable configuration of a self-interstitial atom in the neutral charge state (I 0 ) is the split configuration . The tetrahedral configuration is not stable, an interstitial atom being shifted from T position in a new position T 1 on a distance Δd=0.2 A. The hexagonal configuration is not stable in NDDO approximation. The split interstitial configuration remains the more stable configuration under hydrostatic pressure (P a ( →T 1 )=0.59 eV, E a (T 1 →neighboring T 1 )=0.1 eV and E a (T 1 → )=0.23 eV. The hydrostatic pressure (P<80 kbar) increases the activation barrier for diffusion of self-interstitial atoms in silicon crystals. The energies of the formation of a separate Frenkel pair, a self-interstitial atom, and a vacancy are determined. It is demonstrated that the hydrostatic pressure decreases the energy of the formation of Frenkel pairs.

Self-interstitials, vacancies and their clusters in silicon and germanium

International Nuclear Information System (INIS)

Seeger, A.; Foell, H.; Frank, W.

1976-01-01

The paper begins with a survey of knowledge about swirl defects in silicon. In particular, it is shown that recent identification of the A-swirls as dislocation loops of interstitial type strongly supports a previous suggestion that the predominant equilibrium defects controlling self-diffusion in silicon at high temperatures are self-interstitials. This is followed by a brief state-of-the-art report on self-interstitials in silicon, a field in which rapid progress has been made during the past half a decade. The discussion of vacancy-type defects, which stood in the limelight of the preceding conferences, is confined to some examples of recent interest, such as the interaction of vacancy-type defects with hydrogen atoms, positrons and positive muons. (author)

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

International Nuclear Information System (INIS)

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

2015-01-01

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

A general treatment of one- to three-dimensional diffusion reaction kinetics of interstitial clusters: Implications for the evolution of voids

International Nuclear Information System (INIS)

Trinkaus, H.; Singh, B.N.; Golubov, S.I.

2008-05-01

In recent years, it has been shown that a number of striking features in the microstructural evolution occurring in metals under cascade damage generating irradiation (e.g. enhanced swelling near grain boundaries, decoration of dislocations with SIA loops, saturation of void growth and void lattice formation) can be rationalised in terms of intra-cascade clustering of vacancies and self-interstitial atoms (SIAs), differences in the thermal stability and mobility of the resulting clusters and one-dimensional (1D) glide diffusion of SIA clusters ('production bias model'). The 1D diffusion of SIA clusters is generally disturbed by changes between equivalent 1D diffusion paths and by transversal diffusion by self-climb, resulting in diffusion reaction kinetics between the 1D and 3D limiting cases. In this paper, a general treatment of such kinetics operating in systems containing random distributions of sinks is presented. The complicated partial sink strengths of different components of the system for the annihilation of SIA clusters are expressed by those for the simple 1D and 3D limiting cases. The effects of direction changes and transversal diffusion are first considered separately and are then combined. The significance of the present treatment for damage accumulation under cascade damage conditions is illustrated by applying it to the discussion of void growth characteristics, particularly of the conditions for saturation of void growth. (au)

A general treatment of one- to three-dimensional diffusion reaction kinetics of interstitial clusters: Implications for the evolution of voids

Energy Technology Data Exchange (ETDEWEB)

Trinkaus, H. (Inst. Festkoerperforschung, Forschungszentrum Juelich (Germany)); Singh, B.N. (Risoe DTU, Roskilde (Denmark)); Golubov, S.I. (Oak Ridge National Lab., Materials Science and Technology Div., TN (United States))

2008-05-15

In recent years, it has been shown that a number of striking features in the microstructural evolution occurring in metals under cascade damage generating irradiation (e.g. enhanced swelling near grain boundaries, decoration of dislocations with SIA loops, saturation of void growth and void lattice formation) can be rationalised in terms of intra-cascade clustering of vacancies and self-interstitial atoms (SIAs), differences in the thermal stability and mobility of the resulting clusters and one-dimensional (1D) glide diffusion of SIA clusters ('production bias model'). The 1D diffusion of SIA clusters is generally disturbed by changes between equivalent 1D diffusion paths and by transversal diffusion by self-climb, resulting in diffusion reaction kinetics between the 1D and 3D limiting cases. In this paper, a general treatment of such kinetics operating in systems containing random distributions of sinks is presented. The complicated partial sink strengths of different components of the system for the annihilation of SIA clusters are expressed by those for the simple 1D and 3D limiting cases. The effects of direction changes and transversal diffusion are first considered separately and are then combined. The significance of the present treatment for damage accumulation under cascade damage conditions is illustrated by applying it to the discussion of void growth characteristics, particularly of the conditions for saturation of void growth. (au)

Self-interstitial configuration in molybdenum studied by modified ...

Indian Academy of Sciences (India)

The negative values refer a motion along negative direction of axis. It is noted that the displacements of NN atoms to a SIA are very large compared to those to a vacancy in ref. [1]. This is because adding a SIA into normal matrix will result in a large decrease in interatomic distance and thus a large increase in the acting ...

Anelastic relaxation of interstitial foreign atoms and their complexes with intrinsic defects in B.C.C. metals

International Nuclear Information System (INIS)

Weller, M.

1985-01-01

In body-centred cubic metals, heavy interstitial foreign atoms (IFA) O, N and C give rise to relaxations of Snoek type. For dilute alloys, relaxation parameters are summarized. In concentrated alloys (group Va metals containing O or N) Snoek relaxations are influenced by the interaction of IFA. The recent controversy is discussed as to whether this interaction is based on clustering or anticlustering. In irradiated metals complexes of IFA with intrinsic atomic defects (vacancies or self interstitial atoms) also give rise to relaxations

The features of the atomic structure of the impurities complexes in the irradiated materials doped by the elements with a large atomic radii

International Nuclear Information System (INIS)

Neklyudov, I.M.; Sleptsov, A.N.; Marchenko, I.G.; Sleptsov, S.N.

1995-01-01

The interaction between impurity atoms and radiation-induced defects in Ni(Sc), Ni(Ti), Ni(Pr) and Ni(Y) alloys irradiated with 5 and 30 MeV electrons were studied by the residual resistivity measurements, and the methods of reciprocal damage rate and positron annihilation. The activation energies of the main recovery stages in pure nickel (I D+E - 54 K, II 4 -250 K, III 2 - 390 K) and dilute alloys (up to 700 K) were determined. The radii trapping, r t , of self-interstitial atoms (SIA) by the Sc and Ti atoms were calculated in the temperature range 45-300 K.It is found that the scandium atoms (among all large atomic size elements) are effective traps for SIA and vacancies and form compound complexes. The binding energy of vacancy-impurity complexes are about 0.25, 0.30 and 0.6 - 0.8 eV in Ni(Ti), Ni(Y) and Ni(Sc) alloys, respectively. The solubilities of Sc, Ti, Y and Pr in nickel were deduced from the analysis of dependence of the specific residual resistivity (ρ t ) and the lattice parameter (Δa/a) on concentration. 38 refs., 3 tab., 10 figs

Segregation of cascade induced interstitial loops at dislocations: possible effect on initiation of plastic deformation

Energy Technology Data Exchange (ETDEWEB)

Trinkaus, H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Festkoerperforschung; Singh, B.N. [Materials Research Department, Risoe National Laboratory, DK-4000 Roskilde (Denmark); Foreman, A.J.E. [Materials Performance Department, Harwell Laboratory, Oxfordshire OX11 0RA (United Kingdom)

1997-11-01

In metals and alloys subjected to cascade damage dislocations are frequently found to be decorated with a high density of small clusters of self-interstitial atoms (SIAs) in the form of dislocation loops. In the present paper it is shown that this effect may be attributed to the glide and trapping of SIA loops, produced directly in cascades (rather than to the enhanced agglomeration of single SIAs), in the strain field of the dislocations. The conditions for the accumulation of glissile SIA loops near dislocations as well as the dose and temperature dependencies of this phenomenon are discussed. It is suggested that the decoration of dislocations with loops may play a key role in radiation hardening subjected to cascade damage. It is shown, for example, that the increase in the upper yield stress followed by a yield drop and plastic instability in metals andalloys subjected to cascade damage cannot be rationalized in terms of conventional dispersed barrier hardening (DBH) but may be understood in terms of cascade induced source hardening (CISH) in which the dislocations are considered to be locked by the loops decorating them. Estimates for the stress necessary to pull a dislocation away from its loop `cloud` are used to discuss the dose and temperature dependence of plastic flow initiation. (orig.). 55 refs.

Segregation of cascade induced interstitial loops at dislocations: possible effect on initiation of plastic deformation

International Nuclear Information System (INIS)

Trinkaus, H.; Foreman, A.J.E.

1997-01-01

In metals and alloys subjected to cascade damage dislocations are frequently found to be decorated with a high density of small clusters of self-interstitial atoms (SIAs) in the form of dislocation loops. In the present paper it is shown that this effect may be attributed to the glide and trapping of SIA loops, produced directly in cascades (rather than to the enhanced agglomeration of single SIAs), in the strain field of the dislocations. The conditions for the accumulation of glissile SIA loops near dislocations as well as the dose and temperature dependencies of this phenomenon are discussed. It is suggested that the decoration of dislocations with loops may play a key role in radiation hardening subjected to cascade damage. It is shown, for example, that the increase in the upper yield stress followed by a yield drop and plastic instability in metals andalloys subjected to cascade damage cannot be rationalized in terms of conventional dispersed barrier hardening (DBH) but may be understood in terms of cascade induced source hardening (CISH) in which the dislocations are considered to be locked by the loops decorating them. Estimates for the stress necessary to pull a dislocation away from its loop 'cloud' are used to discuss the dose and temperature dependence of plastic flow initiation. (orig.)

Dynamics of defect-loaded grain boundary under shear deformation in alpha iron

Science.gov (United States)

Yang, L.; Zhou, H. L.; Liu, H.; Gao, F.; Zu, X. T.; Peng, S. M.; Long, X. G.; Zhou, X. S.

2018-02-01

Two symmetric tilt grain boundaries (GBs) (Σ3〈110〉{112} and Σ11〈110〉{332}) in alpha iron were performed to investigate the dynamics of defect-loaded GBs under shear deformation. The results show that the loaded self-interstitial atoms (SIAs) reduce the critical stress of the coupled GB motion in the Σ3 GB, but increase the critical stress in the Σ11 GB. The loaded SIAs in the Σ3 GB easily form 〈111〉 clusters and remain in the bulk when the GB moves away. However, the SIAs move along with the Σ11 GB and combine with the vacancies in the bulk, leading to the defect self-healing. The helium (He) atoms loaded into the GBs significantly affect the coupled GB motion. Once He clusters emit interstitials, the Σ11 GB carries those interstitials away but the Σ3 does not. The loaded He atoms reduce the critical stress of the Σ3 GB, but increase the critical stress of the Σ11 GB.

Internal reflection of interstitial atoms from close-packed tungsten faces

International Nuclear Information System (INIS)

Dranova, Zh.I.; Mikhajlovskij, I.M.

1981-01-01

Use of field-ion microscopy methods has shown that changes in microtopography of tungsten specimens irradiated with 2-5 keV helium atoms are mainly related to the liberation of interstitial atoms on the surface. It is established that the atom liberation on the surface is considerably anisotropic: maximum quantity of atoms is observed in the vicinity of faces (100), (111) and (211) along the sections of zone lines (110) oriented along the edge of the first Brillouin zone. The atom liberation on plane sections of the most dense-packed face (110) was not observed as a rule; atomic steps of the face are interstitial atom sinks. It is concluded on the basis of the results obtained that there is the predominant inner reflection of interstitial atoms from the dense-packed faces and a possible contribution of inner reflection to the surface migration processes activated with the ion bombardment as well as material swelling have been analyzed [ru

Generalized Rate Theory for Void and Bubble Swelling and its Application to Plutonium Metal Alloys

Energy Technology Data Exchange (ETDEWEB)

Allen, P. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wolfer, W. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-10-16

In the classical rate theory for void swelling, vacancies and self-interstitials are produced by radiation in equal numbers, and in addition, thermal vacancies are also generated at the sinks, primarily at edge dislocations, at voids, and at grain boundaries. In contrast, due to the high formation energy of self-interstitials for normal metals and alloys, their thermal generation is negligible, as pointed out by Bullough and Perrin. However, recent DFT calculations of the formation energy of self-interstitial atoms in bcc metals have revealed that the sum of formation and migration energies for self-interstitials atoms (SIA) is of the same order of magnitude as for vacancies. The ratio of the activation energies for thermal generation of SIA and vacancies is presented. For fcc metals, this ratio is around three, but for bcc metals it is around 1.5. Reviewing theoretical predictions of point defect properties in δ-Pu, this ratio could possibly be less than one. As a result, thermal generation of SIA in bcc metals and in plutonium must be taken into considerations when modeling the growth of voids and of helium bubbles, and the classical rate theory (CRT) for void and bubble swelling must be extended to a generalized rate theory (GRT).

Effects of applied strain on nanoscale self-interstitial cluster formation in BCC iron

Science.gov (United States)

Gao, Ning; Setyawan, Wahyu; Kurtz, Richard J.; Wang, Zhiguang

2017-09-01

The effect of applied strains on the configurational evolution of self-interstitial clusters in BCC iron (Fe) is explored with atomistic simulations. A novel cluster configuration is discovered at low temperatures (family of 〈 hkl 〉 loops is calculated as a function of strain. The results show that loop anisotropy is governed by the angle between the stress direction and the orientation of the 〈 111 〉 crowdions in the loop, and directly linked to the stress induced preferred nucleation of self-interstitial atoms.

Effects of applied strain on nanoscale self-interstitial cluster formation in BCC iron

Energy Technology Data Exchange (ETDEWEB)

Gao, Ning; Setyawan, Wahyu; Kurtz, Richard J.; Wang, Zhiguang

2017-09-01

The effect of applied strains on the configurational evolution of self-interstitial clusters in BCC iron (Fe) is explored with atomistic simulations. A novel cluster configuration is discovered at low temperatures (<600 K), which consists of <110> dumbbells and <111> crowdions in a specific configuration, resulting in an immobile defect. The stability and diffusion of this cluster at higher temperatures is explored. In addition, an anisotropy distribution factor of a particular [hkl] interstitial loop within the family of loops is calculated as a function of strain. The results show that loop anisotropy is governed by the angle between the stress direction and the orientation of the <111> crowdions in the loop, and directly linked to the stress induced preferred nucleation of self-interstitial atoms.

Identifying self-interstitials of bcc and fcc crystals in molecular dynamics

Science.gov (United States)

Bukkuru, S.; Bhardwaj, U.; Warrier, M.; Rao, A. D. P.; Valsakumar, M. C.

2017-02-01

Identification of self-interstitials in molecular dynamics (MD) simulations is of critical importance. There exist several criteria for identifying the self-interstitial. Most of the existing methods use an assumed cut-off value for the displacement of an atom from its lattice position to identify the self-interstitial. The results obtained are affected by the chosen cut-off value. Moreover, these chosen cut-off values are independent of temperature. We have developed a novel unsupervised learning algorithm called Max-Space Clustering (MSC) to identify an appropriate cut-off value and its dependence on temperature. This method is compared with some widely used methods such as effective sphere (ES) method and nearest neighbor sphere (NNS) method. The cut-off radius obtained using our method shows a linear variation with temperature. The value of cut-off radius and its temperature dependence is derived for five bcc (Cr, Fe, Mo, Nb, W) and six fcc (Ag, Au, Cu, Ni, Pd, Pt) crystals. It is seen that the ratio of the cut-off values "r" to the lattice constant "a" lies between 0.23 and 0.3 at 300 K and this ratio is on an average smaller for the fcc crystals. Collision cascade simulations are carried out for Primary knock-on Atom (PKA) energies of 5 keV in Fe (at 300 K and 1000 K) and W (at 300 K and 2500 K) and the results are compared using the various methods.

Generalized Rate Theory for Void and Bubble Swelling and its Application to Delta-Plutonium

Energy Technology Data Exchange (ETDEWEB)

Allen, P. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wall, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wolfer, W. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-10-04

A rate theory for void and bubble swelling is derived that allows both vacancies and self-interstitial atoms to be generated by thermal activation at all sinks. In addition, they can also be produced by displacement damage from external and internal radiation. This generalized rate theory (GRT) is applied to swelling of gallium-stabilized δ-plutonium in which α-decay causes the displacement damage. Since the helium atoms produced also become trapped in vacancies, a distinction is made between empty and occupied vacancies. The growth of helium bubbles observed by transmission electron microscopy (TEM) in weapons-grade and in material enriched with Pu238 is analyzed, using different values for the formation energy of self-interstitial atoms (SIA) and two different sets of relaxation volumes for the vacancy and for the SIA. One set allows preferential capture of SIA at dislocations, while the other set gives equal preference to both vacancy and SIA. It is found that the helium bubble diameters observed are in better agreement with GRT predictions if no preferential capture occurs at dislocations. Therefore, helium bubbles in δ-plutonium will not evolve into voids. The helium density within the bubbles remains sufficiently high to cause thermal emission of SIA. Based on a helium density between two to three helium atoms per vacant site, the sum of formation and migration energies must be around 2.0 eV for SIA in δ-plutonium.

Review of Calculations on Point Defect Properties in Delta-Pu

Energy Technology Data Exchange (ETDEWEB)

Allen, P. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wolfer, W. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-09-08

The results of theoretical predictions of properties for vacancies and self-interstitial atoms (SIA) in δ-Pu are presented and reviewed. Three methods have been used for these predictions, namely the modified embedded atom method (MEAM), density functional theory (DFT) with and without spin polarization, and continuum mechanics (CM) models adapted to plutonium. The properties considered are formation and migration energies, and relaxation volumes of vacancies and SIA. Predicted values vary considerably. Nevertheless, all three methods predict that the activation energy for self-diffusion by vacancies is of similar magnitude as the SIA formation energy. Furthermore, the absolute magnitudes of relaxation volumes for vacancies and SIA are also similar, indicating that there exist no large bias for radiation-induced void swelling.

Review of Calculations on Point Defect Properties in Delta-Pu

International Nuclear Information System (INIS)

Allen, P. G.; Wolfer, W. G.

2015-01-01

The results of theoretical predictions of properties for vacancies and self-interstitial atoms (SIA) in δ-Pu are presented and reviewed. Three methods have been used for these predictions, namely the modified embedded atom method (MEAM), density functional theory (DFT) with and without spin polarization, and continuum mechanics (CM) models adapted to plutonium. The properties considered are formation and migration energies, and relaxation volumes of vacancies and SIA. Predicted values vary considerably. Nevertheless, all three methods predict that the activation energy for self-diffusion by vacancies is of similar magnitude as the SIA formation energy. Furthermore, the absolute magnitudes of relaxation volumes for vacancies and SIA are also similar, indicating that there exist no large bias for radiation-induced void swelling.

Derivation of kinetic coefficients by atomistic methods for studying defect behavior in Mo

International Nuclear Information System (INIS)

Insepov, Z.; Rest, J.; Yacout, A.M.; Kuksin, A.Yu.; Norman, G.E.; Stegailov, V.V.; Starikov, S.V.; Yanilkin, A.V.

2012-01-01

Highlights: ► A multiscale concept couples molecular dynamics (MD) with ab initio and kinetic rate theory. ► Evolution of a system of self-interstitial atoms and vacancies in Mo is studied by MD. ► Formation of di-SIA clusters and SIA–vacancy recombination is analyzed. ► 1D diffusion of self-interstitials at various temperature and defect concentrations were studied. ► This paper provides a powerful predictive tool for simulating irradiation of nuclear materials. - Abstract: A multiscale concept for irradiated materials simulation is formulated based on coupling molecular dynamics simulations (MD) where the potential was obtained from ab initio data of energies of the basic defect structures, with kinetic mesoscale models. The evolution of a system containing self-interstitial atoms (SIAs) and vacancies in crystalline molybdenum is investigated by means of MD. The kinetics of formation of di-SIA clusters and SIA–vacancy recombination is analyzed via approaches used in the kinetic theory of radiation ageing. The effects of 1D diffusion of SIAs, temperature, and defect concentrations on the reaction rates are also studied. This approach can validate both the kinetic mechanisms and the appropriate kinetic coefficients, offering the potential to significantly reduce the uncertainty of the kinetic methodology and providing a powerful predictive tool for simulating irradiation behavior of nuclear materials.

Identifying self-interstitials of bcc and fcc crystals in molecular dynamics

International Nuclear Information System (INIS)

Bukkuru, S.; Bhardwaj, U.; Warrier, M.; Rao, A.D.P.; Valsakumar, M.C.

2017-01-01

Identification of self-interstitials in molecular dynamics (MD) simulations is of critical importance. There exist several criteria for identifying the self-interstitial. Most of the existing methods use an assumed cut-off value for the displacement of an atom from its lattice position to identify the self-interstitial. The results obtained are affected by the chosen cut-off value. Moreover, these chosen cut-off values are independent of temperature. We have developed a novel unsupervised learning algorithm called Max-Space Clustering (MSC) to identify an appropriate cut-off value and its dependence on temperature. This method is compared with some widely used methods such as effective sphere (ES) method and nearest neighbor sphere (NNS) method. The cut-off radius obtained using our method shows a linear variation with temperature. The value of cut-off radius and its temperature dependence is derived for five bcc (Cr, Fe, Mo, Nb, W) and six fcc (Ag, Au, Cu, Ni, Pd, Pt) crystals. It is seen that the ratio of the cut-off values “r” to the lattice constant “a” lies between 0.23 and 0.3 at 300 K and this ratio is on an average smaller for the fcc crystals. Collision cascade simulations are carried out for Primary knock-on Atom (PKA) energies of 5 keV in Fe (at 300 K and 1000 K) and W (at 300 K and 2500 K) and the results are compared using the various methods. - Highlights: • Max-Space Clustering (MSC) method is developed to identify interstitials in crystals. • MSC provides a structured way to identify the temperature dependent cut-off radius. • It is compared with widely used sphere methods and found to be better. • MSC coupled with graph tree optimization can be used to obtain diffusion trajectory. • Cascade simulations of Fe, W are carried out and results are compared with various methods.

Identifying self-interstitials of bcc and fcc crystals in molecular dynamics

Energy Technology Data Exchange (ETDEWEB)

Bukkuru, S., E-mail: srinivasaraobukkuru@gmail.com [Dept. of Nuclear Physics, Andhra University, Visakhapatnam 530003 (India); Bhardwaj, U., E-mail: haptork@gmail.com [Computational Analysis Division, BARC, Visakhapatnam 530012, Andhra Pradesh (India); Warrier, M., E-mail: manoj.warrier@gmail.com [Computational Analysis Division, BARC, Visakhapatnam 530012, Andhra Pradesh (India); Rao, A.D.P., E-mail: adp_rao_99@yahoo.com [Dept. of Nuclear Physics, Andhra University, Visakhapatnam 530003 (India); Valsakumar, M.C., E-mail: mc.valsakumar@gmail.com [IIT Palakkad, Kozhippara P.O., Palakkad 678557, Kerala (India)

2017-02-15

Identification of self-interstitials in molecular dynamics (MD) simulations is of critical importance. There exist several criteria for identifying the self-interstitial. Most of the existing methods use an assumed cut-off value for the displacement of an atom from its lattice position to identify the self-interstitial. The results obtained are affected by the chosen cut-off value. Moreover, these chosen cut-off values are independent of temperature. We have developed a novel unsupervised learning algorithm called Max-Space Clustering (MSC) to identify an appropriate cut-off value and its dependence on temperature. This method is compared with some widely used methods such as effective sphere (ES) method and nearest neighbor sphere (NNS) method. The cut-off radius obtained using our method shows a linear variation with temperature. The value of cut-off radius and its temperature dependence is derived for five bcc (Cr, Fe, Mo, Nb, W) and six fcc (Ag, Au, Cu, Ni, Pd, Pt) crystals. It is seen that the ratio of the cut-off values “r” to the lattice constant “a” lies between 0.23 and 0.3 at 300 K and this ratio is on an average smaller for the fcc crystals. Collision cascade simulations are carried out for Primary knock-on Atom (PKA) energies of 5 keV in Fe (at 300 K and 1000 K) and W (at 300 K and 2500 K) and the results are compared using the various methods. - Highlights: • Max-Space Clustering (MSC) method is developed to identify interstitials in crystals. • MSC provides a structured way to identify the temperature dependent cut-off radius. • It is compared with widely used sphere methods and found to be better. • MSC coupled with graph tree optimization can be used to obtain diffusion trajectory. • Cascade simulations of Fe, W are carried out and results are compared with various methods.

OBJECT KINETIC MONTE CARLO SIMULATIONS OF RADIATION DAMAGE IN BULK TUNGSTEN

Energy Technology Data Exchange (ETDEWEB)

Nandipati, Giridhar; Setyawan, Wahyu; Heinisch, Howard L.; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

2015-09-22

We used our recently developed lattice based OKMC code; KSOME [1] to carryout simulations of radiation damage in bulk W. We study the effect of dimensionality of self interstitial atom (SIA) diffusion i.e. 1D versus 3D on the defect accumulation during irradiation with a primary knock-on atom (PKA) energy of 100 keV at 300 K for the dose rates of 10-5 and 10-6 dpa/s. As expected 3D SIA diffusion significantly reduces damage accumulation due to increased probability of recombination events. In addition, dose rate, over the limited range examined here, appears to have no effect in both cases of SIA diffusion.

Anisotropy migration of self-point defects in dislocation stress fields in BCC Fe and FCC Cu

International Nuclear Information System (INIS)

Sivak, A.B.; Chernov, V.M.; Dubasova, N.A.; Romanov, V.A.

2007-01-01

Spatial dependence of the interaction energies of self-point defects (vacancies and self interstitial atoms in stable, metastable and saddle point configurations) with edge dislocations in slip systems {1 1 0} and {1 0 0} in BCC Fe and {1 1 1} in FCC Cu was calculated using the anisotropic theory of elasticity and molecular statics (hybrid method). The migration pathways of vacancies and SIA ( dumbbell in Fe and dumbbell in Cu) along which the migration of the defects with the lowest energy barriers were defined in the presence of the dislocation stress fields. These pathways are significantly different in the stress fields of dislocations

Ab initio study of interstitial cluster interaction with Re, Os, and Ta in W

Energy Technology Data Exchange (ETDEWEB)

Setyawan, Wahyu, E-mail: wahyu.setyawan@pnnl.gov; Nandipati, Giridhar; Kurtz, Richard J.

2017-02-15

The stability of tungsten self-interstitial atom (SIA) clusters is studied using first-principles methods. Clusters from one to seven SIAs are systematically explored from 1264 unique configurations. Finite-size effect of the simulation cell is corrected based on the scaling of formation energy versus inverse volume cell. Furthermore, the accuracy of the calculations is improved by treating the 5p semicore states as valence states. Configurations of the three most stable clusters in each cluster size n are presented, which consist of parallel [111] dumbbells. The evolution of these clusters leading to small dislocation loops is discussed. The binding energy of size-n clusters is analyzed relative to an n → (n-1) + 1 dissociation and is shown to increase with size. Extrapolation for n > 7 is presented using a dislocation loop model. In addition, the interaction of these clusters with a substitutional Re, Os, or Ta solute is explored by replacing one of the dumbbells with the solute. Re and Os strongly attract these clusters, but Ta strongly repels. The strongest interaction is found when the solute is located on the periphery of the cluster rather than in the middle. The magnitude of this interaction decreases with cluster size. Empirical fits to describe the trend of the solute binding energy are presented. - Highlights: • Systematic DFT exploration of tungsten SIA clusters from 1264 configurations. • Detailed structures of several most stable clusters are presented. • Novel finding of the trend of solute binding of Re, Os, and Ta with SIA clusters. • Empirical models that describe the trends of the solute binding energies.

Ab initio study of interstitial cluster interaction with Re, Os, and Ta in W

International Nuclear Information System (INIS)

Setyawan, Wahyu; Nandipati, Giridhar; Kurtz, Richard J.

2017-01-01

The stability of tungsten self-interstitial atom (SIA) clusters is studied using first-principles methods. Clusters from one to seven SIAs are systematically explored from 1264 unique configurations. Finite-size effect of the simulation cell is corrected based on the scaling of formation energy versus inverse volume cell. Furthermore, the accuracy of the calculations is improved by treating the 5p semicore states as valence states. Configurations of the three most stable clusters in each cluster size n are presented, which consist of parallel [111] dumbbells. The evolution of these clusters leading to small dislocation loops is discussed. The binding energy of size-n clusters is analyzed relative to an n → (n-1) + 1 dissociation and is shown to increase with size. Extrapolation for n > 7 is presented using a dislocation loop model. In addition, the interaction of these clusters with a substitutional Re, Os, or Ta solute is explored by replacing one of the dumbbells with the solute. Re and Os strongly attract these clusters, but Ta strongly repels. The strongest interaction is found when the solute is located on the periphery of the cluster rather than in the middle. The magnitude of this interaction decreases with cluster size. Empirical fits to describe the trend of the solute binding energy are presented. - Highlights: • Systematic DFT exploration of tungsten SIA clusters from 1264 configurations. • Detailed structures of several most stable clusters are presented. • Novel finding of the trend of solute binding of Re, Os, and Ta with SIA clusters. • Empirical models that describe the trends of the solute binding energies.

GeAs and SiAs monolayers: Novel 2D semiconductors with suitable band structures

Science.gov (United States)

Zhou, Liqin; Guo, Yu; Zhao, Jijun

2018-01-01

Two dimensional (2D) materials provide a versatile platform for nanoelectronics, optoelectronics and clean energy conversion. Based on first-principles calculations, we propose a novel kind of 2D materials - GeAs and SiAs monolayers and investigate their atomic structure, thermodynamic stability, and electronic properties. The calculations show that monolayer GeAs and SiAs sheets are energetically and dynamically stable. Their small interlayer cohesion energies (0.191 eV/atom for GeAs and 0.178 eV/atom for SiAs) suggest easy exfoliation from the bulk solids that exist in nature. As 2D semiconductors, GeAs and SiAs monolayers possess band gap of 2.06 eV and 2.50 eV from HSE06 calculations, respectively, while their band gap can be further engineered by the number of layers. The relatively small and anisotropic carrier effective masses imply fast electric transport in these 2D semiconductors. In particular, monolayer SiAs is a direct gap semiconductor and a potential photocatalyst for water splitting. These theoretical results shine light on utilization of monolayer or few-layer GeAs and SiAs materials for the next-generation 2D electronics and optoelectronics with high performance and satisfactory stability.

Atomistic studies of nucleation of He clusters and bubbles in bcc iron

International Nuclear Information System (INIS)

Yang, L.; Deng, H.Q.; Gao, F.; Heinisch, H.L.; Kurtz, R.J.; Hu, S.Y.; Li, Y.L.; Zu, X.T.

2013-01-01

Atomistic simulations of the nucleation of He clusters and bubbles in bcc iron at 800 K have been carried out using the newly developed Fe–Fe interatomic potential, along with Ackland potential for the Fe–Fe interactions. Microstructure changes were analyzed in detail. We found that a He cluster with four He atoms is able to push out an iron interstitial from the cluster, creating a Frenkel pair. Small He clusters and self-interstitial atom (SIA) can migrate in the matrix, but He-vacancy (He-V) clusters are immobile. Most SIAs form clusters, and only the dislocation loops with a Burgers vector of b = 1/2 appear in the simulations. SIA clusters (or loops) are attached to He-V clusters for He implantation up to 1372 appm, while the He-V cluster–loop complexes with more than one He-V cluster are formed at the He concentration of 2057 appm and larger

Migration of di- and tri-interstitials in silicon

International Nuclear Information System (INIS)

Posselt, M.; Gao, F.; Zwicker, D.

2005-01-01

A comprehensive study on the migration of di- and tri-interstitials in silicon is performed using classical molecular dynamics simulations with the Stillinger-Weber potential. The initial di- and tri-interstitial configurations with the lowest formation energies are determined, and then, the defect migration is investigated for temperatures between 800 and 1600 K. The defect diffusivity and the self-diffusion coefficient per defect are calculated. Compared to the mono-interstitial, the di-interstitial migrates faster, whereas the tri-interstitial diffuses slower. The migration mechanism of the di-interstitial shows a pronounced dependence on the temperature. Like in the case of the mono-interstitial, the mobility of the di-interstitial is higher than the mobility of the lattice atoms during the defect diffusion. On the other hand, the tri-interstitial mobility is lower than the corresponding atomic mobility. The implications of the present results for the analysis of experimental data on defect evolution and migration are discussed

Correlation between self-diffusion in Si and the migration mechanisms of vacancies and self-interstitials: An atomistic study

International Nuclear Information System (INIS)

Posselt, M.; Gao, F.; Bracht, H.

2008-01-01

The migration of point defects in silicon and the corresponding atomic mobility are investigated by comprehensive classical molecular-dynamics simulations using the Stillinger-Weber potential and the Tersoff potential. In contrast to most of the previous studies both the point defect diffusivity and the self-diffusion coefficient per defect are calculated separately so that the diffusion-correlation factor can be determined. Simulations with both the Stillinger-Weber and the Tersoff potential show that vacancy migration is characterized by the transformation of the tetrahedral vacancy to the split vacancy and vice versa and the diffusion-correlation factor f V is about 0.5. This value was also derived by the statistical diffusion theory under the assumption of the same migration mechanism. The mechanisms of self-interstitial migration are more complex. The detailed study, including a visual analysis and investigations with the nudged elastic band method, reveals a variety of transformations between different self-interstitial configurations. Molecular-dynamics simulations using the Stillinger-Weber potential show that the self-interstitial migration is dominated by a dumbbell mechanism, whereas in the case of the Tersoff potential the interstitialcy mechanism prevails. The corresponding values of the correlation factor f I are different, namely, 0.59 and 0.69 for the dumbbell and the interstitialcy mechanisms, respectively. The latter value is nearly equal to that obtained by the statistical theory which assumes the interstitialcy mechanism. Recent analysis of experimental results demonstrated that in the framework of state-of-the-art diffusion and reaction models the best interpretation of point defect data can be given by assuming f I ≅0.6. The comparison with the present atomistic study leads to the conclusion that the self-interstitial migration in Si should be governed by a dumbbell mechanism

Computer simulation of the interaction between an extended dislocation and radiation defects in the fcc lattice

International Nuclear Information System (INIS)

Kuramoto, E.; Nakamura, Y.; Tsutsumi, T.

1993-01-01

The interaction between an extended dislocation and a radiation-induced defect, especially, a self-interstitial atom (SIA), has been investigated in the model fcc lattice by computer simulation technique. An SIA was absorbed into the core of one of the two partial dislocations of the extended screw dislocation as a crowdion which extends along the dislocation line. Under the applied shear stress this crowdion acted as a pinning point, resulting in irradiation hardening. On the other hand, an SIA was absorbed at the jog site of the extended edge dislocation (at one of the two jog sites on two partial dislocations) and after some relaxation the total jog was shifted to one atomic distance through the spreading out of the strain due to an SIA from one partial side to the other side. (orig.)

Microdefects and self-interstitial diffusion in crystalline silicon

Energy Technology Data Exchange (ETDEWEB)

Knowlton, W.B.

1998-05-01

In this thesis, a study is presented of D-defects and self-interstitial diffusion in silicon using Li ion (Li{sup +}) drifting in an electric field and transmission electron microscopy (TEM). Obstruction of Li{sup +} drifting has been found in wafers from certain but not all FZ p-type Si. Incomplete Li{sup +} drifting always occurs in the central region of the wafers. This work established that interstitial oxygen is not responsible for hindering Li{sup +} drifting. TEM was performed on a samples from the partially Li{sup +} drifted area and compared to regions without D-defects. Precipitates were found only in the region containing D-defects that had partially Li{sup +} drifted. This result indicates D-defects are responsible for the precipitation that halts the Li{sup +} drift process. Nitrogen (N) doping has been shown to eliminate D-defects as measured by conventional techniques. Li{sup +} drifting and D-defects provide a useful means to study Si self-interstitial diffusion. The process modeling program SUPREM-IV was used to simulate the results of Si self-interstitial diffusion obtained from Li{sup +} drifting experiments. Anomalous results from the Si self-interstitial diffusion experiments forced a re-examination of the possibility of thermal dissociation of D-defects. Thermal annealing experiments that were performed support this possibility. A review of the current literature illustrates the need for more research on the effects of thermal processing on FZ Si to understand the dissolution kinetics of D-defects.

Damage at a tungsten surface induced by impacts of self-atoms

Energy Technology Data Exchange (ETDEWEB)

Wu, Yong [Data Center for High Energy Density Physics, Institute of Applied Physics and, Computational Mathematics, P. O. Box 8009, Beijing 100088 (China); Krstic, Predrag, E-mail: predrag.krstic@stonybrook.edu [Institute for Advanced Computational Science, Stony Brook University, Stony Brook, NY 11794-5250 (United States); Zhou, Fu Yang [College of Material Sciences and Optoelectronic Technology, University of the Chinese Academy of Sciences, P. O. Box 4588, Beijing 100049 (China); Meyer, Fred [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States)

2015-12-15

We study evolution of the surface defects of a 300 K tungsten surface due to the cumulative impact of 0.25–10 keV self-atoms. The simulation is performed by molecular dynamics with bond-order Tersoff-form potentials. At all studied impact energies the computation shows strong defect-recombination effect of both created Frenkel pairs as well as recombination of the implanted atoms with the vacancies created by the sputtering. This leads to a saturation of the cumulative count of vacancies, evident at energies below 2 keV, as long as the implantation per impact atom exceeds sputtering and to a saturation of the interstitial count when production of the sputtered particles per impact atom becomes larger than 1 (in the energy range 2-4 keV). The number of cumulative defects is fitted as functions of impact fluence and energy, enabling their analytical extrapolation outside the studied range of parameters. - Highlights: • We calculated cumulative creation of defects in tungsten by self-atom impact. • At some energies, the defect count saturate with increasing damage dose. • The defects are accumulated in the first few layers of the tungsten surface. • The interstitials are formed predominantly as adatoms.

Propagating self-sustained annealing of radiation-induced interstitial complexes

International Nuclear Information System (INIS)

Bokov, P M; Selyshchev, P A

2016-01-01

A propagating self-sustained annealing of radiation induced defects as a result of thermal-concentration instability is studied. The defects that are considered in the model are complexes. Each of them consists of one atom of impunity and of one interstitial atom. Crystal with defects has extra energy which is transformed into heat during defect annealing. Simulation of the auto-wave of annealing has been performed. The front and the speed of the auto-wave have been obtained. It is shown that annealing occurs in a narrow region of time and space. There are two kinds of such annealing behaviour. In the first case the speed of the auto-wave oscillates near its constant mean value and the front of temperature oscillates in a complex way. In the second case the speed of propagation is constant and fronts of temperature and concentration look like sigmoid functions. (paper)

Detection of the free migration of the self-interstitials in magnesium

Energy Technology Data Exchange (ETDEWEB)

Lauzier, J; Hillairet, J; Duclos, D; Vieux Champagne, A

1986-05-01

This paper describes the first experimental determination of the migration temperature of freely diffusing self-interstitials in magnesium. This observation was made possible by analysis of the elastic modulus and damping variations induced by the pinning of the dislocations by self-interstitials. A marked pinning stage is found between 9 K and 14 K, which is definite evidence for the long-range diffusion of the self-interstitial at these temperatures. Prior data are discussed and reinterpreted in the light of this finding.

As amnésias do contemporâneo

Directory of Open Access Journals (Sweden)

Bruschi, Michel Euclides

1997-01-01

Full Text Available Este artigo faz uma viagem pela mente de Leonard Shelby, personagem principal do filme Amnésia (2000. Esta aventura é feita juntamente com o auxílio das idéias sobre narrativa, self transacional e cultura de Jerome Bruner (1997a, 1997b e 2001. O objetivo é de no final da viagem conseguirmos fazer algumas reflexões sobre as amnésias que vivenciamos na contemporaneidade a partir do nosso olhar sobre Leonard. A primeira amnésia é a da fragmentação que é apontada como uma das causas do vazio de sentidos do nosso tempo. No entanto, a fragmentação não impossibilita a construção de sentidos, sendo apenas um novo dificultador desse processo. A segunda amnésia é a de que através das representações estamos acessando diretamente o mundo exterior, esquecendo de todo o processo que ocorre para construirmos uma representação

Self-trapping of helium in metals

International Nuclear Information System (INIS)

Wilson, W.D.; Bisson, C.L.; Baskes, M.I.

1981-01-01

Atomistic calculations are presented which demonstrate that helium atoms in a metal lattice are able to cluster with each other, producing vacancies and nearby self-interstitial defects. Even a small number of helium atoms is found to be sufficient to create these large distortions. As few as five interstitial helium can spontaneously produce a lattice vacancy and nearby self-interstitial. An eight-helium-atom cluster gives rise to two such defects, and 16 helium atoms to more than five self-interstitial vacancy pairs. It was noted that the self-interstitials prefer to agglomerate on the same ''side'' of the helium cluster rather than to spread themselves out uniformly. The binding energy of each additional helium atom to these clusters increases with helium concentration and the trap is apparently unsaturable. A rate theory using these atomistic binding energies has been used to calculate the kinetics of helium-bubble nucleation and growth. The results are consistent with measurements of the properties of helium resulting from tritium decay

Different properties of polysialic acids synthesized by the polysialyltransferases ST8SIA2 and ST8SIA4.

Science.gov (United States)

Mori, Airi; Hane, Masaya; Niimi, Yuki; Kitajima, Ken; Sato, Chihiro

2017-09-01

Polysialic acid (polySia) is mainly found as a modification of neural cell adhesion molecule (NCAM) in whole embryonic brains, as well as restricted areas of adult vertebrate brains, including the hippocampus. PolySia shows not only repulsive effects on NCAM-involved cell-cell interactions due to its bulky and hydrated properties, but also attractive effects on the interaction with neurologically active molecules, which exerts a reservoir function. Two different polysialyltransferases, ST8SIA2 and ST8SIA4, are involved in the synthesis of polySia chains; however, to date, the differences of the properties between polySia chains synthesized by these two enzymes remain unknown. In this study, to clarify this point, we first prepared polySia-NCAMs from HEK293 cells stably expressing ST8SIA4 and ST8SIA2, or ST8SIA2 (SNP-7), a mutant ST8SIA2 derived from a schizophrenia patient. The conventional sensitive chemical and immunological characterizations showed that the quantity and quality (structural features) of polySia are not so much different between ST8SIA4- and ST8SIA2-synthesized ones, apart from those of ST8SIA2 (SNP-7). Then, we assessed the homophilic and heterophilic interactions mediated by polySia-NCAM by adopting a surface plasmon resonance measurement as an in vitro analytical method. Our novel findings are as follows: (i) the ST8SIA2- and ST8SIA4-synthesized polySia-NCAMs exhibited different attractive and repulsive effects than each other; (ii) both polySia- and oligoSia-NCAMs synthesized by ST8SIA2 were able to bind polySia-NCAMs; (iii) the polySia-NCAM synthesized by a ST8SIA2 (SNP-7) showed markedly altered attractive and repulsive properties. Collectively, polySia-NCAM is suggested to simultaneously possess both attractive and repulsive properties that are highly regulated by the two polysialyltransferases. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Di-interstitial defect in silicon revisited

International Nuclear Information System (INIS)

Londos, C. A.; Antonaras, G.; Chroneos, A.

2013-01-01

Infrared spectroscopy was used to study the defect spectrum of Cz-Si samples following fast neutron irradiation. We mainly focus on the band at 533 cm −1 , which disappears from the spectra at ∼170 °C, exhibiting similar thermal stability with the Si-P6 electron paramagnetic resonance (EPR) spectrum previously correlated with the di-interstitial defect. The suggested structural model of this defect comprises of two self-interstitial atoms located symmetrically around a lattice site Si atom. The band anneals out following a first-order kinetics with an activation energy of 0.88 ± 0.3 eV. This value does not deviate considerably from previously quoted experimental and theoretical values for the di-interstitial defect. The present results indicate that the 533 cm −1 IR band originates from the same structure as that of the Si-P6 EPR spectrum

Stability and mobility of self-interstitials and small interstitial clusters in α-iron: ab initio and empirical potential calculations

International Nuclear Information System (INIS)

Willaime, F.; Fu, C.C.; Marinica, M.C.; Dalla Torre, J.

2005-01-01

The stability and mobility of self-interstitials and small interstitial clusters, I n , in α-Fe is investigated by means of calculations performed in the framework of the density functional theory using the SIESTA code. The mono-, di- and tri-interstitials are shown to be made of (parallel) dumbbells and to migrate by nearest-neighbor translation-rotation jumps, according to Johnson's mechanism. The orientation of the dumbbells becomes energetically more favourable for I 5 and larger clusters. The performance of a semi-empirical potential recently developed for Fe, including ab initio self-interstitial data in the fitted properties, is evaluated over the present results. The superiority over previous semi-empirical potentials is confirmed. Finally the impact of the present results on the formation mechanism of loops, observed experimentally in α-Fe is discussed

New insights into canted spiro carbon interstitial in graphite

Science.gov (United States)

EL-Barbary, A. A.

2017-12-01

The self-interstitial carbon is the key to radiation damage in graphite moderator nuclear reactor, so an understanding of its behavior is essential for plant safety and maximized reactor lifetime. The density functional theory is applied on four different graphite unit cells, starting from of 64 carbon atoms up to 256 carbon atoms, using AIMPRO code to obtain the energetic, athermal and mechanical properties of carbon interstitial in graphite. This study presents first principles calculations of the energy of formation that prove its high barrier to athermal diffusion (1.1 eV) and the consequent large critical shear stress (39 eV-50 eV) necessary to shear graphite planes in its presence. Also, for the first time, the gamma surface of graphite in two dimensions is calculated and found to yield the critical shear stress for perfect graphite. Finally, in contrast to the extensive literature describing the interstitial of carbon in graphite as spiro interstitial, in this work the ground state of interstitial carbon is found to be canted spiro interstitial.

Role of Si self-interstitials on the electrical de-activation of B doped

International Nuclear Information System (INIS)

Piro, A.M.; Romano, L.; Badala, P.; Mirabella, S.; Grimaldi, M.G.; Rimini, E.

2006-01-01

The off-lattice displacement of B atoms in B-doped Si induced by the irradiation with light ion beam at room temperature has been investigated. A proton beam with energy ranging from 300 to 1300 keV was used to irradiate the single crystal Si samples containing a 400 nm thick surface layer (grown by molecular beam epitaxy) uniformly doped with B at a concentration of 1 x 10 2 B/cm 3 . Channelling analyses along the axis using the 11 B(p, α) 8 Be reaction (at 650 keV proton energy) were used to detect the off-lattice displacements of B during irradiation. B is substitutional in the as-grown sample. During irradiation the normalized channelling yield of B χ B increases with the ion fluence and saturates at a value χ F smaller than unity, being this value independent of the energy of the irradiating beam. No change on the Si channelling yield was detected. The B displacement rate decreases with increasing the beam energy, it is controlled by the generation rate of Si self-interstitials, and it can be fitted by the following formula χ = χ F - [χ F - χ ] * exp(-σ * N I ), where χ is the χ of the non-irradiated sample, N I is the fluence of the Si self-interstitials generated by the irradiating beam and σ is a fitting parameter that accounts for the probability for a self-interstitial to be trapped by substitutional B. Displaced B is not randomly located in the lattice and channelling analyses indicate the formation of a B complex, mediated by B i intersticialcy diffusion mechanism, partially displaced within the channel

Formation and annealing of metastable (interstitial oxygen)-(interstitial carbon) complexes in n- and p-type silicon

CERN Document Server

Makarenko, L F; Lastovskii, S B; Murin, L I; Moll, M; Pintilie, I

2014-01-01

It is shown experimentally that, in contrast to the stable configuration of (interstitial carbon)-(interstitial oxygen) complexes (CiOi), the corresponding metastable configuration (CiOi{*}) cannot be found in n-Si based structures by the method of capacitance spectroscopy. The rates of transformation CiOi{*} -> CiOi are practically the same for both n- and p-Si with a concentration of charge carriers of no higher than 10(13) cm(-3). It is established that the probabilities of the simultaneous formation of stable and metastable configurations of the complex under study in the case of the addition of an atom of interstitial carbon to an atom of interstitial oxygen is close to 50\\%. This is caused by the orientation dependence of the interaction potential of an atom of interstitial oxygen with an interstitial carbon atom, which diffuses to this oxygen atom.

Atomic displacements due to interstitial hydrogen in Cu and Pd

Indian Academy of Sciences (India)

Total energy calculations and molecular dynamics simulations employing DFT are reliable tools ... as well as predicting equilibrium and non-equilibrium properties. Self-consistent ..... produced by interstitial hydrogen in Cu and Pd. The quantity of central interest .... These numbers are in reasonable qualitative agreement.

Atomic-resolution study of homogeneous radiation-induced precipitation in a neutron-irradiated W-10 at. % Re alloy. MSC report No. 5014

International Nuclear Information System (INIS)

Herschitz, R.; Seidman, D.N.

1983-06-01

The phenomenon of radiation-induced precipitation has been investigated in a W-10 at. % Re alloy using the atom-probe field-ion microscope. Results show a significant alteration of the microstructure of this alloy as a result of the fast-neutron irradiation. Precipitates with the composition approx. WRe (sigma phase) were detected at a density of 10 16 cm -3 . Coherent, semicoherent and possibly incoherent precipitates of the sigma phase have been observed. They were not associated with either linear or planar defects, or with any impurity atoms; i.e. a true homogeneous radiation-induced precipitation occurs in this alloy. A physical argument is presented for the nucleation of the sigma phase precipitates in the vicinity of displacement cascades produced by primary knock-on atoms. It is suggested that the nucleation of the sigma phase is due to the formation of tightly-bound mobil mixed dumbells which react to form an immobile rhenium cluster. The growth of this cluster into a precipitate is most likely driven by the irreversible vacancy: self-interstitial atom (SIA) annihilation reaction, as suggested recently by Cauvin and Martin. A mechanism for the suppression of voids, in this alloy, is presented which is self-consistent with the homogeneous radiation-induced precipitation mechanism

Change of Energy of the Cubic Subnanocluster of Iron Under Influence of Interstitial and Substitutional Atoms.

Science.gov (United States)

Nedolya, Anatoliy V; Bondarenko, Natalya V

2016-12-01

Energy change of an iron face-centred cubic subnanocluster was evaluated using molecular mechanics method depending on the position of a carbon interstitial atom and substitutional atoms of nickel. Calculations of all possible positions of impurity atoms show that the energy change of the system are discrete and at certain positions of the atoms are close to continuous.In terms of energy, when all impurity atoms are on the same edge of an atomic cluster, their positions are more advantageous. The presence of nickel atoms on the edge of a cubic cluster resulted in decrease of potential barrier for a carbon atom and decrease in energy in the whole cluster. A similar drift of a carbon atom from central octahedral interstitial site to the surface in the direction occurred under the influence of surface factors.Such configuration corresponds to decreasing symmetry and increasing the number of possible energy states of a subnanocluster, and it corresponds to the condition of spontaneous crystallization process in an isolated system.Taking into account accidental positions of the nickel atom in the iron cluster, such behaviour of the carbon atom can explain the mechanism of growth of a new phase and formation of new clusters in the presence of other kind of atoms because of surface influence.

Determination of interstitial oxygen atom position in U2N3+xOy by near edge structure study

Science.gov (United States)

Jiang, A. K.; Zhao, Y. W.; Long, Z.; Hu, Y.; Wang, X. F.; Yang, R. L.; Bao, H. L.; Zeng, R. G.; Liu, K. Z.

2018-06-01

The determination of interstitial oxygen atom site in U2N3+xOy film could facilitate the understanding of the oxidation mechanism of α-U2N3 and the effect of U2N3+xOy on anti-oxidation. By comparing the similarities and variances between N K edge and O K edge electron energy loss spectra (EELS) for oxidized α-U2N3 and UO2, the present work looks at the local structure of nitrogen and oxygen atoms in U2N3+xOy film, identifying the most possible position of interstitial O atom.

Microstructural evolution under high flux irradiation of dilute Fe-CuNiMnSi alloys studied by an atomic kinetic Monte Carlo model accounting for both vacancies and self interstitials

International Nuclear Information System (INIS)

Vincent, E.; Becquart, C.S.; Domain, C.

2008-01-01

Under neutron irradiation, a large amount of point defects (vacancies and interstitials) are created. In the irradiated pressure vessel steels, weakly alloyed, these point defects are responsible for the diffusion of the solute atoms, leading to the formation of solute rich precipitates within the matrix. Ab initio calculations based on the density functional theory have been performed to determine the interactions of point defects with solute atoms in dilute FeX alloys (X = Cu, Mn, Ni or Si). For Mn, the results of these calculations lead to think that solute transport in α-Fe can very likely take place through an interstitial mechanism as well as via vacancies while the other solutes (Cu, Ni and Si) which establish strong bonds with vacancies diffuse more likely via vacancies only. The database thus created has been used to parameterize an atomic kinetic Monte Carlo model taking into account both vacancies and interstitials. Some results of irradiation damage in dilute Fe-CuNiMnSi alloys obtained with this model will be presented

Microstructural evolution under high flux irradiation of dilute Fe CuNiMnSi alloys studied by an atomic kinetic Monte Carlo model accounting for both vacancies and self interstitials

Science.gov (United States)

Vincent, E.; Becquart, C. S.; Domain, C.

2008-12-01

Under neutron irradiation, a large amount of point defects (vacancies and interstitials) are created. In the irradiated pressure vessel steels, weakly alloyed, these point defects are responsible for the diffusion of the solute atoms, leading to the formation of solute rich precipitates within the matrix. Ab initio calculations based on the density functional theory have been performed to determine the interactions of point defects with solute atoms in dilute FeX alloys (X = Cu, Mn, Ni or Si). For Mn, the results of these calculations lead to think that solute transport in α-Fe can very likely take place through an interstitial mechanism as well as via vacancies while the other solutes (Cu, Ni and Si) which establish strong bonds with vacancies diffuse more likely via vacancies only. The database thus created has been used to parameterize an atomic kinetic Monte Carlo model taking into account both vacancies and interstitials. Some results of irradiation damage in dilute Fe-CuNiMnSi alloys obtained with this model will be presented.

First-principles investigation of the energetics of point defects at a grain boundary in tungsten

Energy Technology Data Exchange (ETDEWEB)

Chai, Jun; Li, Yu-Hao; Niu, Liang-Liang; Qin, Shi-Yao; Zhou, Hong-Bo, E-mail: hbzhou@buaa.edu.cn; Jin, Shuo; Zhang, Ying; Lu, Guang-Hong

2017-02-15

Tungsten (W) and W alloys are considered as the most promising candidates for plasma facing materials in future fusion reactor. Grain boundaries (GBs) play an important role in the self-healing of irradiation defects in W. Here, we investigate the stability of point defects [vacancy and self-interstitial atoms (SIA’s)] in a Σ5(3 1 0) [0 0 1] tilt W GB by calculating the energetics using a first-principles method. It is found that both the vacancy and SIA are energetically favorable to locate at neighboring sites of the GB, suggesting the vacancy and SIA can easily segregate to the GB region with the segregation energy of 1.53 eV and 7.5 eV, respectively. This can be attributed to the special atomic configuration and large available space of the GB. The effective interaction distance between the GB and the SIA is ∼6.19 Å, which is ∼2 Å larger than that of the vacancy-GB, indicating the SIA are more preferable to locate at the GB in comparison with the vacancy. Further, the binding energy of di-vacancies in the W GB are much larger than that in bulk W, suggesting that the vacancy energetically prefers to congregate in the GB.

The behavior of interstitials in irradiated graphite

International Nuclear Information System (INIS)

Pedraza, D.F.

1991-01-01

A computer model is developed to simulate the behavior of self-interstitials with particular attention to clustering. Owing to the layer structure of graphite, atomistic simulations can be performed using a large parallelepipedic supercell containing a few layers. In particular, interstitial clustering is studied here using a supercell that contains two basal planes only. Frenkel pairs are randomly produced. Interstitials are placed at sites between the crystal planes while vacancies are distributed in the two crystal planes. The size of the computational cell is 20000 atoms and periodic boundary conditions are used in two dimensions. Vacancies are assumed immobile whereas interstitials are given a certain mobility. Two point defect sinks are considered, direct recombination of Frenkel pairs and interstitial clusters. The clusters are assumed to be mobile up to a certain size where they are presumed to become loop nuclei. Clusters can shrink by emission of singly bonded interstitials or by recombination of a peripheral interstitial with a neighboring vacancy. The conditions under which interstitial clustering occurs are reported. It is shown that when clustering occurs the cluster size population gradually shifts towards the largest size cluster. The implications of the present results for irradiation growth and irradiation-induced amorphization are discussed

Annihilation of interstitial-type dislocation loops in {alpha}-Fe during He irradiation

Energy Technology Data Exchange (ETDEWEB)

Xu, Q., E-mail: xu@rri.kyoto-u.ac.jp [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan); Wang, Y.X. [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Katakabe, Y. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580 (Japan); Iwakiri, H. [Faculty of Education, University of the Ryukyus, Okinawa 903-0213 (Japan); Yoshida, N. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580 (Japan); Sato, K.; Yoshiie, T. [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan)

2011-10-01

Interstitial-type dislocation loops were formed in Fe-9Cr alloys on irradiation with 1-MeV He ions at 673 K. However, with increasing irradiation dose, the dislocation loops shrunk. A molecular dynamics simulation was used to elucidate the mechanism of this unexpected phenomenon. The simulation shows that, although the binding energy of a self-interstitial atom to a dislocation loop is normally greater than that of a vacancy, the energy hierarchy is reversed when He atoms decorate the loop. This may indicates preferential absorption of vacancies, causing loop shrinkage at high doses, consistent with experimental observation.

Annihilation of interstitial-type dislocation loops in α-Fe during He irradiation

International Nuclear Information System (INIS)

Xu, Q.; Wang, Y.X.; Katakabe, Y.; Iwakiri, H.; Yoshida, N.; Sato, K.; Yoshiie, T.

2011-01-01

Interstitial-type dislocation loops were formed in Fe-9Cr alloys on irradiation with 1-MeV He ions at 673 K. However, with increasing irradiation dose, the dislocation loops shrunk. A molecular dynamics simulation was used to elucidate the mechanism of this unexpected phenomenon. The simulation shows that, although the binding energy of a self-interstitial atom to a dislocation loop is normally greater than that of a vacancy, the energy hierarchy is reversed when He atoms decorate the loop. This may indicates preferential absorption of vacancies, causing loop shrinkage at high doses, consistent with experimental observation.

Absence of saturation of void growth in rate theory with anisotropic diffusion

CERN Document Server

Hudson, T S; Sutton, A P

2002-01-01

We present a first attempt at solution the problem of the growth of a single void in the presence of anisotropically diffusing radiation induced self-interstitial atom (SIA) clusters. In order to treat a distribution of voids we perform ensemble averaging over the positions of centres of voids using a mean-field approximation. In this way we are able to model physical situations in between the Standard Rate Theory (SRT) treatment of swelling (isotropic diffusion), and the purely 1-dimensional diffusion of clusters in the Production Bias Model. The background absorption by dislocations is however treated isotropically, with a bias for interstitial cluster absorption assumed similar to that of individual SIAs. We find that for moderate anisotropy, unsaturated void growth is characteristic of this anisotropic diffusion of clusters. In addition we obtain a higher initial void swelling rate than predicted by SRT whenever the diffusion is anisotropic.

In-situ field-ion microscope study of the recovery behavior of heavy metal ion-irradiated tungsten, tungsten (rhenium) alloys and molybdenum

International Nuclear Information System (INIS)

Nielsen, C.H.

1977-06-01

Three field ion microscope (FIM) experiments were carried out to study the annealing behavior of heavy ion irradiated tungsten, tungsten (rhenium) alloys and molybdenum. The first experiment dealt with the stage I long-range migration of tungsten self interstitial atoms (SIAs) in high purity tungsten of resistivity ratio, R = 24,000 (R = rho 300 /rho 4 . 2 , where rho 300 and rho 4 . 2 are the room temperature and 0 0 C resistivities). The FIM specimens were irradiated in situ at 18 K with 30 keV W + ions to an average dose of 5 x 10 12 ions cm -2 and subsequently examined by the pulsed-field evaporation technique. The second experiment dealt with the phenomenon of impurity atom trapping of SIAs during long-range migration. It was shown that rhenium atoms in a tungsten matrix tend to capture tungsten SIAs and remain bound up to temperatures as high as 390 K. The final experiment was concerned with the low temperature annealing kinetics of irradiated molybdenum. High purity molybdenum of resistivity ratio R = 5700 was irradiated at 10 K with 30 keV Mo + ions to a dose of approximately 5 x 10 12 ions cm -2 . The results indicated that the electric field has only a minimal effect on the SIA annealing kinetics. This tends to strengthen the contention that the molybdenum SIA becomes mobile at 32 K

Computer simulation of interstitial atom loop with vacancies in gamma-iron lattice

International Nuclear Information System (INIS)

Golubov, S.I.; Doronina, V.I.; Kaipetskaya, E.N.

1985-01-01

The interaction of vacanies and a dislocation loop has been investigated by the mashine stimulation method. The calculations have been performed by the variation method using the Jonson pair potential for gamma-iron. The interaction of a vacancy and a loop of interstitial atoms in the form of a regular hexagon has been investigated. The results obtained are compared with calculations in the elastic approximation

First-principles study of the diffusion mechanisms of the self-interstitial in germanium

International Nuclear Information System (INIS)

Carvalho, A; Jones, R; Janke, C; Goss, J P; Briddon, P R; Oeberg, S

2008-01-01

The self-interstitial in germanium can assume multiple configurations depending on the temperature and charge state. Here, we employ a first-principles density functional method to investigate the diffusion mechanisms of this defect. The energy barriers associated with the transformation between different structures are determined by the climbing nudged elastic band method, as a function of the charge state. The relation between the thermodynamic properties of the self-interstitial and the temperature evolution of electron radiation damage in germanium are discussed

Modeling of interstitial diffusion of ion-implanted boron

International Nuclear Information System (INIS)

Velichko, O.I.; Knyazheva, N.V.

2009-01-01

A model of the interstitial diffusion of ion-implanted boron during rapid thermal annealing of silicon layers previously amorphized by implantation of germanium has been proposed. It is supposed that the boron interstitials are created continuously during annealing due to generation, dissolution, or rearrangement of the clusters of impurity atoms which are formed in the ion-implanted layers with impurity concentration above the solubility limit. The local elastic stresses arising due to the difference of boron atomic radius and atomic radius of silicon also contribute to the generation of boron interstitials. A simulation of boron redistribution during thermal annealing for 60 s at a temperature of 850 C has been carried out. The calculated profile agrees well with the experimental data. A number of the parameters of interstitial diffusion have been derived. In particular, the average migration length of nonequilibrium boron interstitials is equal to 12 nm. It was also obtained that approximately 1.94% of boron atoms were converted to the interstitial sites, participated in the fast interstitial migration, and then became immobile again transferring into a substitutional position or forming the electrically inactive complexes with crystal lattice defects. (authors)

How is environmental conflict addressed by SIA?

International Nuclear Information System (INIS)

Barrow, C.J.

2010-01-01

The fields of Environmental Conflict Management (ECM), Environmental Conflict Resolution (ECR), and Peace and Conflict Impact Assessment (PCIA) have become well established; however, as yet there has not been much use of Social Impact Assessment (SIA) to manage environmental conflicts. ECM, ECR and PCIA are mainly undertaken when problems are advanced or, more likely, have run their course (post-conflict). This paper examines how conflict is addressed by SIA and whether there is potential to develop it for more proactive assessment of conflicts (pre-conflict or while things develop). SIA has the potential to identify and clarify the cause(s) of environmental and natural resources conflicts, and could possibly enable some avoidance or early mitigation. A promising approach may be for 'conflict-aware' SIA to watch for critical conflict stages or thresholds and to monitor stakeholders. Effective conflict-aware SIA might also significantly contribute to efforts to achieve sustainable development.

A first-principles investigation of interstitial defects in dilute tungsten alloys

Energy Technology Data Exchange (ETDEWEB)

Gharaee, Leili; Erhart, Paul, E-mail: erhart@chalmers.se

2015-12-15

The thermodynamic properties of intrinsic and extrinsic (Ti, V, Zr, Nb, Hf, Ta, Re) defects in tungsten have been investigated using density functional theory calculations. The formation energies of substitutional defects are discussed with respect to their thermodynamic solubility limits. Several different interstitial configurations have been identified as local minima on the potential energy surface. In addition to dumbbell configurations with orientations along 〈111〉 and 〈110〉, a lower symmetry configuration is described, which is referred to as a bridge interstitial. This interstitial type is found to be the lowest energy configuration for mixed-interstitials containing Ti, V, and Re, and can be up to 0.2 eV lower in energy than the other configurations. According to the calculations Ti, V and Re also trap self-interstitial atoms, which can be produced in substantial numbers during ion irradiation, affecting the mobility of the latter.

Strain Fields And Crystallographic Characteristics Of Interstitial Dislocation Loops of Various Geometry In BCC Iron

International Nuclear Information System (INIS)

Sivak, Alexander B.; Chernov, Viatcheslav M.; Romanov, Vladimir A.

2008-01-01

The formation energy, the relaxation volume, the dipole-force tensor, the self strain tensor and strain fields of interstitial dislocation loops in bcc iron (clusters of self interstitial atoms) have been calculated by molecular statics. Hexagonal and square dislocation loops of different types with different Burgers vectors, directions of dislocation segments and habit planes containing up to ∼2500 self-interstitials have been considered. Analytical expressions describing size dependence of the formation energy, the relaxation volume and the self strain tensor for the loops stated have been obtained. The most energetically favorable loops are hexagonal loops with Burgers vector a/2 and habit plane {11x}, where x takes values in the range from 0 to 1 depending on the loop size. The formation energy of a loops with and dislocation segments is ∼14% and 23% greater than that of hexagonal a/2 loops at N>500, respectively. The analysis of the formation energies of a/2 and a loops demonstrated that the nucleation of an a loop by joining of two a/2 loops is possible when the total number of constituent self-interstitials in these loops is larger than 13

Interactions of foreign interstitial and substitutional atoms in bcc iron from ab initio calculations

Science.gov (United States)

You, Y.; Yan, M. F.

2013-05-01

C and N atoms are the most frequent foreign interstitial atoms (FIAs), and often incorporated into the surface layers of steels to enhance their properties by thermochemical treatments. Al, Si, Ti, V, Cr, Mn, Co, Ni, Cu, Nb and Mo are the most common alloying elements in steels, also can be called foreign substitutional atoms (FSAs). The FIA and FSA interactions play an important role in the diffusion of C and N atoms, and the microstructures and mechanical properties of surface modified layers. Ab initio calculations based on the density functional theory are carried out to investigate FIA interactions with FSA in ferromagnetic bcc iron. The FIA-FSA interactions are analyzed systematically from five aspects, including interaction energies, density of states (DOS), bond populations, electron density difference maps and local magnetic moments.

Determination of the population of octahedral and tetrahedral interstitials in zirconium hydrides

International Nuclear Information System (INIS)

Fedorov, V.M.; Gogava, V.V.; Shilo, S.I.; Biryukova, E.A.

1983-01-01

Results of neutron investigations of ZrHsub(1.66), ZrHsub(1.75) and ZrHsub(1.98) zirconium hydrides are presented. Investigations were conducted using plane polycrystal samples by multidetector system of scattered neutron detection. Neutron diffraction method was used to determine the number of interstitial hydrogen atoms in interstitials of the lattice cell in the case of statistic atom distribution. The numbers of interstitial atoms in octahedral interstitials for zirconium hydrides were determined experimentally; the difference of potential energies of hydrogen atoms in octa- and tetrahedral interstitials was determined as well. It is shown that experimentally determined difference of potential energies of hydrogen atoms, occupying octa- and tetrahedral positions in investigated zirconium hydrides results at room temperature in the pretailing occupation of tetrahedral interstitials by hydrogen atoms (85-90%); the occupation number grows with temperature decrease and the ordering of interstitial vacancies with formation of hydrogen superstructure takes place at low temperatures

Modeling radiation damage near grain boundary in helium-doped α-iron

Energy Technology Data Exchange (ETDEWEB)

Xu, C.P. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou, Gansu 730000 (China); Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Liu, X.-Y. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Gao, F. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Li, Y.H. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou, Gansu 730000 (China); Wang, Y.Q., E-mail: yqwang@lanl.gov [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2014-08-01

Molecular dynamics (MD) simulations are performed to investigate how ∑3〈110〉(1 2 1) symmetric tilt grain boundary (GB) affects point defects and defect clusters in He-doped α-iron at 300 K in picosecond time scales. Molecular statics calculations are also performed and show that the formation energy is reduced in the GB, and the GB acts as a good sink for point defects, especially for interstitial He and self-interstitial atoms (SIAs). It is observed that the average size of He{sub n}V{sub m} (m > n) clusters becomes smaller in the GB-containing Fe system, where m and n represent the number of vacancies and He atoms in the cluster, respectively. It is also found that the number of He{sub n}V (n = 2, 3) clusters in the GB region decreases, while the number of the HeV clusters increases. The GBs loaded with substitutional or interstitial helium atoms are found to facilitate the growth of helium clusters in the GB region.

Gigantic uphill drift of vacancies and self-interstitials in silicon

International Nuclear Information System (INIS)

Voronkov, V.V.; Falster, R.

2009-01-01

Point defect transport in a growing crystal includes a drift along the temperature gradient, G, at a velocity αG. It was not clear if the drift is negligible or strong in silicon crystal growth. It is now found that reported microdefect patterns in crystals grown with a temporarily halt provide a clear evidence in favour of a strong (even gigantic) drift of both kinds of intrinsic point defects. The drift coefficients α V (for vacancies) and α I (for self-interstitials) are deduced by fitting the simulating defect profiles to the observed location of halt-induced interstitial region immersed into a vacancy-type crystal.

Defect accumulation under cascade damage conditions

DEFF Research Database (Denmark)

Trinkaus, H.; Singh, B.N.; Woo, C.H.

1994-01-01

in terms of this reaction kinetics taking into account cluster production, dissociation, migration and annihilation at extended sinks. Microstructural features which are characteristic of cascade damage and cannot be explained in terms of the conventional single defect reaction kinetics are emphasized......There is now ample evidence from both experimental and computer simulation studies that in displacement cascades not only intense recombination takes place but also efficient clustering of both self-interstitial atoms (SIAs) and vacancies. The size distributions of the two types of defects produced...... reactions kinetics associated with the specific features of cascade damage is described, with emphasis on asymmetries between SIA and vacancy type defects concerning their production, stability, mobility and interactions with other defects. Defect accumulation under cascade damage conditions is discussed...

Self-interstitials structure in the hcp metals: A further perspective from first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Pasianot, Roberto C., E-mail: pasianot@cnea.gov.ar [Gerencia Materiales, CAC-CNEA, Avda. Gral. Paz 1499, 1650 San Martín (Argentina); CONICET, Godoy Cruz 2290, 1425 Buenos Aires (Argentina); Instituto Sabato, UNSAM/CNEA, Avda. Gral. Paz 1499, 1650 San Martín (Argentina)

2016-12-01

We study the structure of several standard and non-standard self-interstitial configurations in a series of hcp metals, by using Density Functional Theory as embodied in the computer codes SIESTA and WIEN2k. The considered metals include Be, Mg, Ti, Zr, Co, Zn, and Cd, thus spanning the whole range of experimental c/a ratios, different kinds of bonding, and even magnetism (Co). The results show the importance of low symmetry configurations, closely related to the non-basal crowdion, in order to rationalize the experimental data on self-interstitial structure and migration.

Clinical validation of a non-heteronormative version of the Social Interaction Anxiety Scale (SIAS).

Science.gov (United States)

Lindner, Philip; Martell, Christopher; Bergström, Jan; Andersson, Gerhard; Carlbring, Per

2013-12-19

Despite welcomed changes in societal attitudes and practices towards sexual minorities, instances of heteronormativity can still be found within healthcare and research. The Social Interaction Anxiety Scale (SIAS) is a valid and reliable self-rating scale of social anxiety, which includes one item (number 14) with an explicit heteronormative assumption about the respondent's sexual orientation. This heteronormative phrasing may confuse, insult or alienate sexual minority respondents. A clinically validated version of the SIAS featuring a non-heteronormative phrasing of item 14 is thus needed. 129 participants with diagnosed social anxiety disorder, enrolled in an Internet-based intervention trial, were randomly assigned to responding to the SIAS featuring either the original or a novel non-heteronormative phrasing of item 14, and then answered the other item version. Within-subject, correlation between item versions was calculated and the two scores were statistically compared. The two items' correlations with the other SIAS items and other psychiatric rating scales were also statistically compared. Item versions were highly correlated and scores did not differ statistically. The two items' correlations with other measures did not differ statistically either. The SIAS can be revised with a non-heteronormative formulation of item 14 with psychometric equivalence on item and scale level. Implications for other psychiatric instruments with heteronormative phrasings are discussed.

Self-interstitials and Frenkel pairs in electron-irradiated germanium

International Nuclear Information System (INIS)

Carvalho, A.; Jones, R.; Goss, J.; Janke, C.; Coutinho, J.; Oberg, S.; Briddon, P.R.

2007-01-01

First principles calculations were used to study the structures and electrical levels of the self-interstitial in Ge. We considered the possibility of structural changes consequent with change in charge state and show these have important implications in the mobility and electrical activity of the defect. The theoretical model is compared to the results of low temperature electron irradiation in germanium reported in the literature

Migration of Cr-vacancy clusters and interstitial Cr in α-Fe using the dimer method

International Nuclear Information System (INIS)

Chen, D.; Gao, F.; Hu, S. Y.; Sun, X.; Heinisch, H. L.; Henager, C. H.; Khaleel, M. A.; Hu, W. Y.; Terentyev, D.

2010-01-01

The migration mechanisms and the corresponding activation energies of Cr-vacancy (Cr-V) clusters and Cr interstitials in α-Fe have been investigated using the dimer and the nudged elastic-band methods. Dimer searches are employed to find the possible transition states of these defects and the lowest-energy paths are used to determine the energy barriers for migration. A substitutional Cr atom can migrate to a nearest-neighbor vacancy through an energy barrier of 0.56 eV but this simple mechanism alone is unlikely to lead to the long-distance migration of Cr unless there is a supersaturated concentration of vacancies in the system. The Cr-vacancy clusters can lead to long-distance migration of a Cr atom that is accomplished by Fe and Cr atoms successively jumping to nearest-neighbor vacancy positions, defined as a self-vacancy-assisted migration mechanism, with the migration energies ranging from 0.64 to 0.89 eV. In addition, a mixed Cr-Fe dumbbell interstitial can easily migrate through Fe lattices, with the migration energy barrier of 0.17, which is lower than that of the Fe-Fe interstitial. The on-site rotation of the Cr-Fe interstitial and Cr atom hopping from one site to another are believed to comprise the dominant migration mechanism. The calculated binding energies of Cr-V clusters are strongly dependent on the size of clusters and the concentration of Cr atoms in clusters.

Effects of stacking fault energies on the interaction between an edge dislocation and an 8.0-nm-diameter Frank loop of self-interstitial atoms

Directory of Open Access Journals (Sweden)

S. Hayakawa

2016-12-01

Full Text Available Molecular dynamics simulations were conducted to investigate the effects of stacking fault energy (SFE as a single variable parameter on the interaction between an edge dislocation and a Frank loop of self-interstitial atoms with a diameter of 8.0nm. The physical contact between the edge dislocation and the loop causes constriction of the edge dislocation, followed by the formation of a D-Shockley partial dislocation. The latter process is associated with either the formation of a screw component and its cross-slip, or the direct core reaction between the dislocation and the loop. These processes induce either the absorption of the loop into the dislocation or the transformation of the loop into a perfect loop. The SFE influences the interaction morphologies by determining the separation distance of the two partial dislocations and consequently the rate of constriction. The dependence of the interaction morphology on the SFE varies with the habit plane of the loop. A higher SFE increases the probability of the absorption or transformation interaction; however, only loop shearing is observed at the lower limit of the SFE range of austenitic stainless steels.

Resonant vibrations of self-interstitials in fcc metals with application to specific heat and neutron scattering

International Nuclear Information System (INIS)

Ram, P.N.; Dederichs, P.H.

1981-07-01

Some aspects of resonant vibrations of self-interstitials in the 100-dumbbell configuration in fcc-metals are discussed by extending previous calculations of Zeller et al. and Schober et al. Employing a simple defect model with nearest-neighbour interaction the local frequency spectrum of the defect is calculated showing several localized modes and low-frequency resonant modes. The change in the total density of states due to the defects is expressed as the derivative of a generalized phase shift which is used to calculate the change in the lattic specific heat due to single interstitials. Inelastic neutron scattering away from the one-phonon lines is proposed as a method to observe the resonant modes induced by self-interstitials. The model calculation in Cu shows that the well defined resonant modes due to dumbbell vibrations have appreciable intensity and could presumably be detected in neutron scattering measurements. The effect of di-interstitials on the phonon dispersion in Al is also discussed. (orig./GSCH)

Huang scattering from self-interstitials in electron-irradiated Fe-40 at % Al ordered alloy

International Nuclear Information System (INIS)

Guillot, J.P.; Riviere, J.P.; Beaufort-Richard, M.F.

1983-01-01

A single crystal of Fe-40 at % Al ordered alloy has been irradiated with 2.5 MeV electrons at liquid hydrogen temperature, and diffuse X-ray scattering (MoKα 1 ) near Bragg reflections has been studied after annealing the sample up to 300 K. The characteristic diffuse scattering from point defects with weak displacement fields (Huang diffusion) has been observed near the (200) Bragg reflection in the directions [011] and [100] and near the (110) reflection in the directions [110] and [110]. This Huang scattering has been attributed to self interstitials since under the same irradiations conditions, electrical resistivity measurements indicate that the long range migration of self interstitials by annihilation at vacancies would occur only for temperatures higher than 300 K. The comparison of the experimental results with the different simple intertitial configurations proposed for b.c.c. crystals suggest that the most probable configuration should be the [110] split interstitial with orthorhombic symmetry [fr

Code switching in Sia Pedee story-telling

NARCIS (Netherlands)

Gómez Rendón, J.

2010-01-01

This article deals with code switching in a corpus of narratives collected in Sia Pedee (Chocoan) among the Épera of the northern Pacific coast of Ecuador. The reinsertion of Sia Pedee in the nowadays dominant Spanish-speaking ethnic community has resulted in older speakers making use of code

The effect of C concentration on radiation damage in Fe–Cr–C alloys

Energy Technology Data Exchange (ETDEWEB)

Meinander, A., E-mail: andrea.meinander@helsinki.fi [EURATOM-Tekes, Department of Physics, P.O. Box 43, FI-00014 University of Helsinki (Finland); Henriksson, K.O.E. [EURATOM-Tekes, Department of Physics, P.O. Box 43, FI-00014 University of Helsinki (Finland); Björkas, C. [EURATOM-Tekes, Department of Physics, P.O. Box 43, FI-00014 University of Helsinki (Finland); Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Jülich (Germany); Vörtler, K.; Nordlund, K. [EURATOM-Tekes, Department of Physics, P.O. Box 43, FI-00014 University of Helsinki (Finland)

2013-11-15

Using a recently developed analytical bond-order potential for the complete ternary system, we performed molecular dynamics simulations of the primary radiation damage by displacement cascades in different Fe–Cr–C model alloys. We compared results obtained with this new potential to previous studies employing potentials for the binary Fe–Cr and Fe–C systems. We analysed the effect of C concentration on the number of Frenkel pairs produced by the cascades, as well as on clustering of vacancies and self-interstitial atoms (SIAs), and on the Cr and C content in the defects. The effect of C concentration on defect production was negligible, except at very high concentrations of over 1 at.% C. The main effect was in the Cr content of clustered SIAs, which increased with increasing C concentration.

Nature of interstitially induced lattice strains

International Nuclear Information System (INIS)

Emin, D.

1978-01-01

The addition of interstitial atoms to a metal lattice has been likened to the addition of extra billiard balls to an array of tangentially touching billiard balls. In such a picture the increased clustering of interstitials can lead to the buildup of larger and larger strain fields which ultimately are associated with the production of broken bonds. Simple models of the strain fields associated with the addition of particles to a lattice in which the force exerted between the added atoms and host atoms is finite have been studied. From these studies one can define situations in which the billiard-ball approach has qualitative validity and those in which it is inappropriate. Basically, those situations in which the displacements of the host atoms can be represented as involving acoustic phonons yield long-range strain fields analogous to those of the billiard-ball model with the radius of the extra billiard ball being determined by the stiffness of the host lattice and the forces between the added atom and the surrounding host atoms. If the displacements produced by the added atoms are represented as involving primarily optical phonons the displacement pattern is short-ranged and not described by the usual elasticity theory. For example, Vegard's law does not apply in these instances. Such concerns arise in considering the strains induced by interstitial helium in tritides

Suppression of self-interstitials in silicon during ion implantation via in-situ photoexcitation

International Nuclear Information System (INIS)

Ravi, J.; Erokhin, Yu.; Christensen, K.; Rozgonyi, G.A.; Patnaik, B.K.; White, C.W.

1995-02-01

The influence of in-situ photoexcitation during low temperature implantation on self-interstitial agglomeration following annealing has been investigated using transmission electron microscopy (TEM). A reduction in the level of as-implanted damage determined by RBS and TEM occurs athermally during 150 keV self-ion implantation. The damage reduction following a 300 C anneal suggests that it is mostly divacancy related. Subsequent thermal annealing at 800 C resulted in the formation of (311) rod like defects or dislocation loops for samples with and without in-situ photoexcitation, respectively. Estimation of the number of self-interstitials bound by these defects in the sample without in-situ photoexcitation corresponds to the implanted dose; whereas for the in-situ photoexcitation sample a suppression of ∼2 orders in magnitude is found. The kinetics of the athermal annealing process are discussed within the framework of either a recombination enhanced defect reaction mechanism, or a charge state enhanced defect migration and Coulomb interaction

Development of a short form Social Interaction Anxiety (SIAS) and Social Phobia Scale (SPS) using nonparametric item response theory: the SIAS-6 and the SPS-6.

Science.gov (United States)

Peters, Lorna; Sunderland, Matthew; Andrews, Gavin; Rapee, Ronald M; Mattick, Richard P

2012-03-01

Shortened forms of the Social Interaction Anxiety Scale (SIAS) and the Social Phobia Scale (SPS) were developed using nonparametric item response theory methods. Using data from socially phobic participants enrolled in 5 treatment trials (N = 456), 2 six-item scales (the SIAS-6 and the SPS-6) were developed. The validity of the scores on the SIAS-6 and the SPS-6 was then tested using traditional methods for their convergent validity in an independent clinical sample and a student sample, as well as for their sensitivity to change and diagnostic sensitivity in the clinical sample. The scores on the SIAS-6 and the SPS-6 correlated as well as the scores on the original SIAS and SPS, with scores on measures of related constructs, discriminated well between those with and without a diagnosis of social phobia, providing cutoffs for diagnosis and were as sensitive to measuring change associated with treatment as were the SIAS and SPS. Together, the SIAS-6 and the SPS-6 appear to be an efficient method of measuring symptoms of social phobia and provide a brief screening tool.

Previsions of the microstructural evolution of ferritic alloys under irradiation by numerical atomic scale simulations

International Nuclear Information System (INIS)

Ngayam Happy, R.

2010-01-01

In this work, we have improved a diffusion model for point defects (vacancies and self-interstitials) by introducing hetero-interstitials. The model has been used to simulate by Kinetic Monte Carlo (KMC) the formation of solute rich clusters that are observed experimentally in irradiated ferritic model alloys of type Fe - CuMnNiSiP - C.Electronic structure calculations have been used to characterize the interactions between self-interstitials and all solute atoms, and also carbon. P interacts with vacancies and strongly with self-interstitials. Mn also interacts with self-interstitials to form mixed dumbbells. C, with occupies octahedral sites, interacts strongly with vacancies and less with self-interstitials. Binding and migration energies, as well as others atomic scale properties, obtained by ab initio calculations, have been used as parameters for the KMC code. Firstly, these parameters have been optimized over isochronal annealing experiments, in the literature, of binary alloys that have been electron-irradiated. Isochronal annealing simulations, by reproducing experimental results, have allowed us to link each mechanism to a single evolution of the resistivity during annealing. Moreover, solubility limits of all the elements have been determined by Metropolis Monte Carlo. Secondly, we have simulated the evolution at 300 C of the microstructure under irradiation of different alloys of increasing complexity: pure Fe, binary alloys, ternaries, quaternaries, and finally complex alloys which compositions are close to those of pressure vessel steels. The results show that the model globally reproduces all the experimental tendencies, what has led us to propose mechanisms to explain the behaviours observed. (author)

Aspects of microstructure evolution under cascade damage conditions

International Nuclear Information System (INIS)

Singh, B.N.; Trinkaus, H.; Barashev, A.V.

1997-01-01

The conventional theoretical models describing the damage accumulation, particularly void swelling, under cascade damage conditions do not include treatments of important features such as intracascade clustering of self-interstitial atoms (SIAs) and one-dimensional glide of SIA clusters produced in the cascades. Recently, it has been suggested that the problem can be treated in terms of 'production bias' and one-dimensional glide of small SIA clusters. In the earlier treatments a 'mean size approximation' was used for the defect clusters and cavities evolving during irradiation. In the present work, we use the 'size distribution function' to determine the dose dependence of sink strengths, vacancy supersaturation and void swelling as a function of dislocation density and grain size within the framework of production bias model and glide of small SIA clusters. In this work, the role of the sessile-glissile loop transformation (due to vacancy supersaturation) on the damage accumulation behaviour is included. The calculated results on void swelling are compared with the experimental results as well as the results of the earlier calculations using the 'mean size approximation'. The calculated results agree very well with the experimental results. (orig.)

Self-lacing atom chains

International Nuclear Information System (INIS)

Zandvliet, Harold J W; Van Houselt, Arie; Poelsema, Bene

2009-01-01

The structural and electronic properties of self-lacing atomic chains on Pt modified Ge(001) surfaces have been studied using low-temperature scanning tunnelling microscopy and spectroscopy. The self-lacing chains have a cross section of only one atom, are perfectly straight, thousands of atoms long and virtually defect free. The atomic chains are composed of dimers that have their bonds aligned in a direction parallel to the chain direction. At low temperatures the atomic chains undergo a Peierls transition: the periodicity of the chains doubles from a 2 x to a 4 x periodicity and an energy gap opens up. Furthermore, at low temperatures (T<80 K) novel quasi-one-dimensional electronic states are found. These quasi-one-dimensional electronic states originate from an electronic state of the underlying terrace that is confined between the atomic chains.

A China e a transformação da Ásia

OpenAIRE

Gaspar, Carlos

2013-01-01

O artigo explora o papel da China na evolução da Ásia no sistema internacional, apresentando as dinâmicas políticas e securitárias que caracterizaram os seus diferentes «centros» - a Ásia Oriental, a Ásia do Nordeste ou a Ásia do Sudeste - e que na viragem do século criaram as condições para a emergência de uma «Grande Ásia», em simultâneo com o reconhecimento da China. São ainda abordados os diferentes conflitos que marcaram a história da região durante a Guerra Fria, e embora o fim da Guerr...

Estimates for diffusion barriers and atomic potentials in MGO

International Nuclear Information System (INIS)

Skala, L.; Kenkre, V.M.

1991-01-01

In this paper, as part of a program of investigation of microwave sintering, self-consistent CNDO/2 calculations are presented for diffusion barriers and potentials for the motion of interstitial atoms and vacancies in MgO. Clusters of 30 atoms are used in the calculations. Activation energies, diffusion barriers, shape of the potentials and electron densities are obtained

The effects of one-dimensional migration of self-interstitial clusters on the formation of void lattices

DEFF Research Database (Denmark)

Heinisch, H.L.; Singh, B.N.

2002-01-01

under pure 3-D SIA migration, but they are extremely stable, relative to random arrays of voids, under 1-D SIA migration. Void lattices remain stable even under the condition of fairly frequent changes in the Burgers vectors of the 1-D migrating SIA clusters. Clusters with average 1-D path segments...

Calculation of the electronic structure optical transitions and contact hyperfine parameters of interstitial hydrogen in alkaline halogen crystals

International Nuclear Information System (INIS)

Maciel, A.K.A.

1977-03-01

The electronic structure of the interstitial hydrogen atom in KF, NaCl, KCl, and RbCl cristals has been studied using the self-consistent-field multiple-scattering Xα method. In the present calculation a cluster constituted by the hydrogen atom surrounded by its first anion and cation neighbors in a cubic shell has been used. The optical transition energies and hyperfine contact parameters with the interstitial proton and the first shell nuclei have been evaluated. The agreement obtained with the experimental data and the relative independence of the method under variations of its intrinsic parameters, indicate that this method can be adequate to the study of defects in ionic cristals. (author) [pt

Atomic defects and diffusion in metals

International Nuclear Information System (INIS)

Siegel, R.W.

1981-11-01

The tracer self-diffusion data for fcc and refractory bcc metals are briefly reviewed with respect to (i) the available monovacancy formation and migration properties and (ii) the high-temperature diffusion enhancement above that expected for mass transport via atomic exchange with monovacancies. While the atomic-defect mechanism for low-temperature self-diffusion can be reliably attributed to monovacancies, the mechanisms responsible for high-temperature mass transport are not so easily defined at this time; both divacancies and interstitials must be seriously considered. Possibilities for improving our understanding in this area are discussed. 68 references, 7 figures

Thermotransport in interstitial solid solutions

International Nuclear Information System (INIS)

Fogel'son, R.L.

1982-01-01

On the basis of literature data the problem of thermotransport of impurities (H, N, O, C) in interstitial solid solutions is considered. It is shown that from experimental data on the thermotransport an important parameter of dissolved atoms can be found which characterizes atom state in these solutions-enthalpy of transport

Mechanism of vacancy formation induced by hydrogen in tungsten

Directory of Open Access Journals (Sweden)

Yi-Nan Liu

2013-12-01

Full Text Available We report a hydrogen induced vacancy formation mechanism in tungsten based on classical molecular dynamics simulations. We demonstrate the vacancy formation in tungsten due to the presence of hydrogen associated directly with a stable hexagonal self-interstitial cluster as well as a linear crowdion. The stability of different self-interstitial structures has been further studied and it is particularly shown that hydrogen plays a crucial role in determining the configuration of SIAs, in which the hexagonal cluster structure is preferred. Energetic analysis has been carried out to prove that the formation of SIA clusters facilitates the formation of vacancies. Such a mechanism contributes to the understanding of the early stage of the hydrogen blistering in tungsten under a fusion reactor environment.

Condensation of helium in interstitial sites of carbon nanotubes bundles

International Nuclear Information System (INIS)

Marcone, B.; Orlandini, E.; Toigo, F.; Ancilotto, F.

2006-01-01

Helium atoms are believed to be strongly bound within the interstitial channels in bundles of carbon nanotubes. In a recent paper [F. Ancilotto et al., Phys. Rev. B 70, 165422 (2004)] inhomogeneity in the size distribution of nanotube radii was shown to make a system of 4 He atoms in such an environment effectively a four-dimensional Bose gas, thus permitting a Bose-Einstein condensation (BEC) of the adsorbed atoms into the minimum energy state. This surprising result was obtained for a model of noninteracting atoms in a continuum distribution of (virtually) infinite interstitial channels. Here we investigate how the singular thermal properties of the ideal system and the occurrence of BEC are affected by a more realistic modeling of a bundle of nanotubes where (i) the number of nanotubes is finite and where (ii) 4 He atoms adsorbed within the same interstitial channel interact among themselves. Also in this case we observe an anomalous heat capacity close to the ideal condensation temperature, suggesting the persistence of the condensation transition for interacting 4 He atoms, which might be experimentally observed

Social Impact Assessment (SIA) from a multidimensional paradigmatic perspective: Challenges and opportunities.

Science.gov (United States)

Aledo-Tur, Antonio; Domínguez-Gómez, J Andrés

2017-06-15

The literature specialized in Social Impact Assessment (SIA) concurs that there is still much work to do in the discussion and thorough grounding of its theories and conceptual bases. The authors of this paper consider that the understanding of SIA as a paradigm may prove useful as a foundation on which more robust and better grounded SIA knowledge production may be built. Further, we suggest that the application of the concept of the paradigm in the terms expressed here may offer a comprehensive guide to practice in SIA studies. The paradigmatic approach to SIA is based on six basic, consecutive questions, related to each other and independent at the same time: questions in the axiological, ontological, epistemological, methodological and theoretical fields, in addition to one on governance in SIA (and in the specific project analysed). We explain how the two currently predominant SIA paradigms (which we have named technocratic and constructivist, following the commonly accepted terms) answer these questions. Finally, the variability of the different answer options may involve intermediate positions between the two paradigms which may also involve comprehensive ways of defining and grounding practice. Copyright © 2016 Elsevier Ltd. All rights reserved.

System dynamic simulation: A new method in social impact assessment (SIA)

International Nuclear Information System (INIS)

Karami, Shobeir; Karami, Ezatollah; Buys, Laurie; Drogemuller, Robin

2017-01-01

Many complex social questions are difficult to address adequately with conventional methods and techniques, due to the complicated dynamics, and hard to quantify social processes. Despite these difficulties researchers and practitioners have attempted to use conventional methods not only in evaluative modes but also in predictive modes to inform decision making. The effectiveness of SIAs would be increased if they were used to support the project design processes. This requires deliberate use of lessons from retrospective assessments to inform predictive assessments. Social simulations may be a useful tool for developing a predictive SIA method. There have been limited attempts to develop computer simulations that allow social impacts to be explored and understood before implementing development projects. In light of this argument, this paper aims to introduce system dynamic (SD) simulation as a new predictive SIA method in large development projects. We propose the potential value of the SD approach to simulate social impacts of development projects. We use data from the SIA of Gareh-Bygone floodwater spreading project to illustrate the potential of SD simulation in SIA. It was concluded that in comparison to traditional SIA methods SD simulation can integrate quantitative and qualitative inputs from different sources and methods and provides a more effective and dynamic assessment of social impacts for development projects. We recommend future research to investigate the full potential of SD in SIA in comparing different situations and scenarios.

System dynamic simulation: A new method in social impact assessment (SIA)

Energy Technology Data Exchange (ETDEWEB)

Karami, Shobeir, E-mail: shobeirkarami@gmail.com [Agricultural Extension and Education, Shiraz University (Iran, Islamic Republic of); Karami, Ezatollah, E-mail: ekarami@shirazu.ac.ir [Agricultural Extension and Education, Shiraz University (Iran, Islamic Republic of); Buys, Laurie, E-mail: l.buys@qut.edu.au [Creative Industries Faculty, School of Design, Queensland University of Technology (Australia); Drogemuller, Robin, E-mail: robin.drogemuller@qut.edu.au [Creative Industries Faculty, School of Design, Queensland University of Technology (Australia)

2017-01-15

Many complex social questions are difficult to address adequately with conventional methods and techniques, due to the complicated dynamics, and hard to quantify social processes. Despite these difficulties researchers and practitioners have attempted to use conventional methods not only in evaluative modes but also in predictive modes to inform decision making. The effectiveness of SIAs would be increased if they were used to support the project design processes. This requires deliberate use of lessons from retrospective assessments to inform predictive assessments. Social simulations may be a useful tool for developing a predictive SIA method. There have been limited attempts to develop computer simulations that allow social impacts to be explored and understood before implementing development projects. In light of this argument, this paper aims to introduce system dynamic (SD) simulation as a new predictive SIA method in large development projects. We propose the potential value of the SD approach to simulate social impacts of development projects. We use data from the SIA of Gareh-Bygone floodwater spreading project to illustrate the potential of SD simulation in SIA. It was concluded that in comparison to traditional SIA methods SD simulation can integrate quantitative and qualitative inputs from different sources and methods and provides a more effective and dynamic assessment of social impacts for development projects. We recommend future research to investigate the full potential of SD in SIA in comparing different situations and scenarios.

Atomic displacements due to interstitial hydrogen in Cu and Pd

Indian Academy of Sciences (India)

2015-11-27

Nov 27, 2015 ... Atomic displacements; density functional theory; Kanzaki method. ... pseudopotentials for H, Cu and Pd are generated self-consistently. ... Both Cu and Pd lattices show lattice expansion due to the presence of hydrogen and ...

Internal friction measurements of Mo after low-temperature proton irradiation

International Nuclear Information System (INIS)

Tanimoto, H.; Mizubayashi, H.; Masuda, R.; Okuda, S.; Tagishi, Y.

1992-01-01

Internal friction measurements are performed in Mo after 20 MeV proton irradiation in order to clarify the behavior of self-interstitial atoms (SIA's) in Mo. In the low dose range, strong dislocation pinning suggesting the free migration of defects is observed at about 40 K and weak pinning at about 25 K. The features are very similar to those reported after neutron irradiation except that the 25 K pinning is much smaller after proton irradiation. The result suggests that the migration of free SIA's is responsible for the 40 K pinning and that of SIA-defect clusters, probably di-SIA's, formed during irradiation for the 25 K pinning. In the high dose range, the relaxation peaks are observed at about 13 and 41 K, where the close similarities are found between the present peaks and the corresponding peaks reported after neutron irradiation except that the peak height of the 41 K peak per unit concentration of Frenkel pairs (FP) tends to increase strongly with decreasing dose here. The latter fact suggests the strong interaction between SIA's. Then the smallness of the 41 K peak reported after electron irradiation with very high dose could be explained by an increased interaction between SIA's, but not by the two-dimensional migration of SIA's as proposed by Jacques and Robrock. Deformation given prior to irradiation causes a drastic decrease in the modulus defects associated with FP's (so-called bulk effect) and in the 13 K peak height. After neutron irradiation, no such effect of deformation was reported. A possible origin for this difference is discussed. (orig.)

Displacement cascades and defects annealing in tungsten, Part I: Defect database from molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Setyawan, Wahyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nandipati, Giridhar [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Roche, Kenneth J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Univ. of Washington, Seattle, WA (United States); Heinisch, Howard L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wirth, Brian D. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab., Oak Ridge, TN (United States); Kurtz, Richard J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-07-01

Molecular dynamics simulations have been used to generate a comprehensive database of surviving defects due to displacement cascades in bulk tungsten. Twenty-one data points of primary knock-on atom (PKA) energies ranging from 100 eV (sub-threshold energy) to 100 keV (~780^×_Ed, where _Ed = 128 eV is the average displacement threshold energy) have been completed at 300 K, 1025 K and 2050 K. Within this range of PKA energies, two regimes of power-law energy-dependence of the defect production are observed. A distinct power-law exponent characterizes the number of Frenkel pairs produced within each regime. The two regimes intersect at a transition energy which occurs at approximately 250^×_Ed. The transition energy also marks the onset of the formation of large self-interstitial atom (SIA) clusters (size 14 or more). The observed defect clustering behavior is asymmetric, with SIA clustering increasing with temperature, while the vacancy clustering decreases. This asymmetry increases with temperature such that at 2050 K (~0.5_Tm) practically no large vacancy clusters are formed, meanwhile large SIA clusters appear in all simulations. The implication of such asymmetry on the long-term defect survival and damage accumulation is discussed. In addition, <100> {110} SIA loops are observed to form directly in the highest energy cascades, while vacancy <100> loops are observed to form at the lowest temperature and highest PKA energies, although the appearance of both the vacancy and SIA loops with Burgers vector of <100> type is relatively rare.

Calculation of the electronic structure and contact hyperfine parameters of interstitial hydrogen in alkaline - earth fluorides

International Nuclear Information System (INIS)

Oliveira, L.E.M.C. de.

1976-01-01

The electronic structure of the interstitial hydrogen atom in alkaline-earth fluorides has been studied using the self-consistent-field multiple-scattering Xα method. In the calculations a cluster constituted by the hydrogen atom and its first anion and cation neighbors has been used. The contact parameters with the proton and the fluorine nuclei have been evaluated. The agreement obtained with the experimental results is in general good and indicates that this method is also appropriate to study defects in ionic crystals. (author) [pt

Parrēsia ed exemplum. La parrēsia e i regimi aleturgici dell’exemplum a partire da L’ermeneutica del soggetto di Michel Foucault

Directory of Open Access Journals (Sweden)

Orazio Irrera

2013-03-01

Full Text Available Questo articolo cerca di esplorare il rapporto tra parrēsia ed exemplum negli ultimi Corsi al Collège de France di Michel Foucault. A partire da L’ermeneutica del soggetto, viene analizzato il campo semantico e pratico relativo alla direzione di coscienza stoica ed epicurea, in cui Foucault oppone la parrēsia all’adulazione e alla retorica per collocarla invece all’interno di un’importante serie di concetti: la paradosis (la trasmissione dei discorsi di verità, il kairos (il momento giusto, la circostanza opportuna e l’exemplum definito come «il cuore della parrēsia» poiché esso assicura l’adæquatio tra il soggetto di enunciazione e il soggetto di comportamento che si conforma alla verità espressa dal primo. Successivamente, viene posta l’attenzione sul legame tra parrēsia ed exemplum nell’ultimo Corso, Il coraggio della verità, per mettere in evidenza un’importante riconfigurazione all’interno della parrēsia cinica, in cui l’esempio appare come una categoria etica basata sulla permanenza e sull’identità a sé. Pertanto, esso si rivela inadeguato per questo regime aleturgico della parrēsia cinica, che invece consiste in un atteggiamento etico sperimentale, una mise à l’épreuve cui sottomettere la vita per arrivare a una trasformazione politica del mondo attraverso una continua e scandalosa provocazione degli altri, in grado di mettere in discussione la percezione di norme culturali e di abitudini consolidate.

COMPARISON OF POSTOP SIA IN MSICS WITH STRAIGHT INCISION VERSUS FROWN INCISION

Directory of Open Access Journals (Sweden)

Shayana Bhumbla

2017-05-01

Full Text Available BACKGROUND Surgically-Induced Astigmatism (SIA is one of the commonest causes of poor postoperative vision even after uneventful cataract surgery. Recent advances have led to a newer concept of “refractive cataract surgery.” The aim of the study is to study the comparison of postop SIA in Manual Small Incision Cataract Surgery (MSICS with straight versus frown incision. MATERIALS AND METHODS 50 patients of cataract were divided into 2 groups (25 each - group A underwent MSICS with 6 mm straight incision, group B underwent MSICS with 6 mm frown incision. BCVA, keratometry readings were recorded with auto kerato-refractometer preop, at 1 week, 1 month, 3 months and SIA was calculated with SIA calculator version 2.1, a free software program. RESULTS Mean SIA in group A and B were - 1.14D versus 0.92D at 1 week; 1.26D versus 0.97D at 1 month; 1.29D versus 0.95D at 3 months. The difference was statistically significant at each follow up visit (p<0.05. CONCLUSION Frown incision gives lesser SIA than straight incision in MSICS.

Clinical validation of a non-heteronormative version of the Social Interaction Anxiety Scale (SIAS)

OpenAIRE

Lindner, Philip; Martell, Christopher; Bergström, Jan; Andersson, Gerhard; Carlbring, Per

2013-01-01

Introduction: Despite welcomed changes in societal attitudes and practices towards sexual minorities, instances of heteronormativity can still be found within healthcare and research. The Social Interaction Anxiety Scale (SIAS) is a valid and reliable self-rating scale of social anxiety, which includes one item (number 14) with an explicit heteronormative assumption about the respondents sexual orientation. This heteronormative phrasing may confuse, insult or alienate sexual minority responde...

Evolutionary history of the alpha2,8-sialyltransferase (ST8Sia) gene family: tandem duplications in early deuterostomes explain most of the diversity found in the vertebrate ST8Sia genes.

Science.gov (United States)

Harduin-Lepers, Anne; Petit, Daniel; Mollicone, Rosella; Delannoy, Philippe; Petit, Jean-Michel; Oriol, Rafael

2008-09-23

The animal sialyltransferases, which catalyze the transfer of sialic acid to the glycan moiety of glycoconjugates, are subdivided into four families: ST3Gal, ST6Gal, ST6GalNAc and ST8Sia, based on acceptor sugar specificity and glycosidic linkage formed. Despite low overall sequence identity between each sialyltransferase family, all sialyltransferases share four conserved peptide motifs (L, S, III and VS) that serve as hallmarks for the identification of the sialyltransferases. Currently, twenty subfamilies have been described in mammals and birds. Examples of the four sialyltransferase families have also been found in invertebrates. Focusing on the ST8Sia family, we investigated the origin of the three groups of alpha2,8-sialyltransferases demonstrated in vertebrates to carry out poly-, oligo- and mono-alpha2,8-sialylation. We identified in the genome of invertebrate deuterostomes, orthologs to the common ancestor for each of the three vertebrate ST8Sia groups and a set of novel genes named ST8Sia EX, not found in vertebrates. All these ST8Sia sequences share a new conserved family-motif, named "C-term" that is involved in protein folding, via an intramolecular disulfide bridge. Interestingly, sequences from Branchiostoma floridae orthologous to the common ancestor of polysialyltransferases possess a polysialyltransferase domain (PSTD) and those orthologous to the common ancestor of oligosialyltransferases possess a new ST8Sia III-specific motif similar to the PSTD. In osteichthyans, we have identified two new subfamilies. In addition, we describe the expression profile of ST8Sia genes in Danio rerio. Polysialylation appeared early in the deuterostome lineage. The recent release of several deuterostome genome databases and paralogons combined with synteny analysis allowed us to obtain insight into events at the gene level that led to the diversification of the ST8Sia genes, with their corresponding enzymatic activities, in both invertebrates and vertebrates. The

Evolutionary history of the alpha2,8-sialyltransferase (ST8Sia gene family: Tandem duplications in early deuterostomes explain most of the diversity found in the vertebrate ST8Sia genes

Directory of Open Access Journals (Sweden)

Petit Jean-Michel

2008-09-01

Full Text Available Abstract Background The animal sialyltransferases, which catalyze the transfer of sialic acid to the glycan moiety of glycoconjugates, are subdivided into four families: ST3Gal, ST6Gal, ST6GalNAc and ST8Sia, based on acceptor sugar specificity and glycosidic linkage formed. Despite low overall sequence identity between each sialyltransferase family, all sialyltransferases share four conserved peptide motifs (L, S, III and VS that serve as hallmarks for the identification of the sialyltransferases. Currently, twenty subfamilies have been described in mammals and birds. Examples of the four sialyltransferase families have also been found in invertebrates. Focusing on the ST8Sia family, we investigated the origin of the three groups of α2,8-sialyltransferases demonstrated in vertebrates to carry out poly-, oligo- and mono-α2,8-sialylation. Results We identified in the genome of invertebrate deuterostomes, orthologs to the common ancestor for each of the three vertebrate ST8Sia groups and a set of novel genes named ST8Sia EX, not found in vertebrates. All these ST8Sia sequences share a new conserved family-motif, named "C-term" that is involved in protein folding, via an intramolecular disulfide bridge. Interestingly, sequences from Branchiostoma floridae orthologous to the common ancestor of polysialyltransferases possess a polysialyltransferase domain (PSTD and those orthologous to the common ancestor of oligosialyltransferases possess a new ST8Sia III-specific motif similar to the PSTD. In osteichthyans, we have identified two new subfamilies. In addition, we describe the expression profile of ST8Sia genes in Danio rerio. Conclusion Polysialylation appeared early in the deuterostome lineage. The recent release of several deuterostome genome databases and paralogons combined with synteny analysis allowed us to obtain insight into events at the gene level that led to the diversification of the ST8Sia genes, with their corresponding enzymatic

Interstitial diffusion in crystal and the Moessbauer effect

International Nuclear Information System (INIS)

Dzyublik, A.Ya.

1976-01-01

The role of different vibrational states of a crystal is taken into account in the model of interstitial uncorrelated jumps. The relation of the diffusion coefficient for an interstitial with probabilities of jumps is found. The cross section for resonant absorption of γ-quanta by a nucleus of a diffusing atom in a crystal is calculated. The existence of vibrational levels is shown to lead to less broadening and intensity of the Moessbauer line than those predicted by the simple model of jumps. The absorption line shape for atom jumping through octahedral sites in bcc lattice is investigated [ru

The influence of non-equilibrium fluctuations on radiation damage and recovery of metals under irradiation

International Nuclear Information System (INIS)

Dubinko, V.I.; Klepikov, V.F.

2007-01-01

In the conventional theory of radiation damage, it is assumed that the main effect of irradiation is due to formation of Frenkel pairs of vacancies and self-interstitial atoms (SIAs) and their clusters. The difference in absorption of vacancies and SIAs by primary or radiation-induced extended defects (EDs) is thought to be the main reason of microstructural evolution under irradiation. On the other hand, the recovery of radiation damage is thought to be driven exclusively by thermal fluctuations resulting in the vacancy evaporation from voids (void annealing) or dislocations (thermal creep) and in the fluctuation-driven overcoming of obstacles by gliding dislocations (plastic strain). However, these recovery mechanisms can be efficient only at sufficiently high temperatures. At lower irradiation temperatures, the main driving force of the recovery processes may be due to nonequilibrium fluctuations of energy states of the atoms surrounding EDs arising as a result of scattering of radiation-induced excitations of atomic and electronic structure at EDs. In the present paper, the mechanisms of nonequilibrium fluctuations that result in such phenomena as the void shrinkage under irradiation at low temperatures (or high dose rates), irradiation creep and irradiation-induced increase of plasticity under sub-threshold irradiation was considered

Influence of stacking fault energies on the size distribution and character of defect clusters formed by collision cascades in face-centered cubic metals

Directory of Open Access Journals (Sweden)

Y. Yang

2016-12-01

Full Text Available Molecular dynamics simulations are performed to evaluate the influence of the stacking fault energy (SFE as a single variable parameter on defect formation by collision cascades in face-centered cubic metals. The simulations are performed for energies of a primary knock-on atom (EPKA up to 50keV at 100K by using six sets of the recently developed embedded atom method–type potentials. Neither the number of residual defects nor their clustering behavior is found to be affected by the SFE, except for the mean size of the vacancy clusters at EPKA=50keV. The mean size increases as the SFE decreases because of the enhanced formation of large vacancy clusters, which prefer to have stacking faults inside them. On the other hand, the ratio of glissile self-interstitial atom (SIA clusters decreases as the SFE increases. At higher SFEs, both the number of Frank loops and number of perfect loops tend to decrease; instead, three-dimensional irregular clusters with higher densities appear, most of which are sessile. The effect of SFE on the number of Frank loops becomes apparent only at a high EPKA of 50keV, where comparably large SIA clusters can be formed with a higher density.

Fine interstitial clusters as recombinators in decomposing solid solutions under irradiation

International Nuclear Information System (INIS)

Trushin, Yu.V.

1991-01-01

Behaviour of interstitial clusters and their roll in processes of radiation swelling of metals are described. It is shown that occurrence of coherent advanced precipitations during decomposition of solid solutions under irradiation leads to matrix supersaturation over interstitial atoms. This enhances recombination of unlike defects due to vacancy precipitation on fine interstitial clusters. Evaluation of cluster sizes was conducted

Mārketinga komunikācijas SIA „Amserv Motors”.

OpenAIRE

Iļjenko, Santa

2013-01-01

Maģistra darba nosaukums ir „Mārketinga komunikācijas SIA „Amserv Motors””. Autore mārketinga komunikācijas pēta uzņēmumā SIA „Amserv Motors”, kas ir Toyota un Lexus oficiālais dīleris Latvijā. Maģistra darba mērķis ir izpētīt SIA „Amserv Motors” mārketinga komunikācijas, izvērtējot to priekšrocības un trūkumus, lai sniegtu priekšlikumus to pilnveidošanas iespējām. Darba pirmajā nodaļā raksturoti mārketinga komunikāciju veidi, to galvenās priekšrocības un trūkumi. Otrajā nodaļā autore a...

Modelling of initial stages of interstitial solid solution decomposition in bcc metals

Energy Technology Data Exchange (ETDEWEB)

Blanter, M S

1982-01-01

By means of a model of deformation interaction of interstitial atoms added by interlocking of the nearest positions the configuration of cluster of alien atoms intruded into octahedral ..cap alpha..-Fe, V, Nb and Ta interstitially sites is computerized. The cluster structure is determined by elastic properties, of the crystal lattice of the metal-solvent. Clusters in ..cap alpha..-Fe have a plate form in a plane (001) of half lattice period width, in V, Nb and Ta - of monatomic plate in a plane (110). Clusters of interstitials must be sufficiently stable and arise even in solutions low concentration.

Dependence of tracer diffusion on atomic size in amorphous Ni-Zr

International Nuclear Information System (INIS)

Hahn, H.; Averback, R.S.

1988-01-01

Tracer diffusion coefficients for several impurities and Ni self-atoms were measured in amorphous (a-) Ni/sub 50/Zr/sub 50/ at 573 K using secondary-ion-mass spectroscopy, Rutherford backscattering, and radioactive tracer methods. The results showed that atomic mobility in the a-Ni-Zr alloy depends strongly on atomic size, decreasing rapidly with increasing atomic radius. This diffusion behavior is similar to that in α-Zr and α-Ti and is suggestive of an interstitial-like mechanism of diffusion. The consequences of these results for solid-state amorphization transformations are discussed

Assessing the performance of SIA in the EIA context: A case study of South Africa

International Nuclear Information System (INIS)

Pisani, Jacobus A. du; Sandham, Luke A.

2006-01-01

This article, a theoretical perspective based on a literature study, is a critical evaluation of SIA as part of the EIA process in South Africa against the background of international guidelines and best practices. It includes sections on the historical background of the development of SIA in South Africa, the legal status and requirements of SIA in the country, and a critical evaluation of SIA regulation in South Africa. The conclusion reached in the article is that the persistent problems of SIA practice, experienced in other parts of the world, are also evident in South Africa. Apart from institutional, financial and professional constraints, there are also serious problems associated with approach and methods. This conclusion confirms the findings of empirical studies that SIA in South Africa is neglected, that the practice of SIA in South Africa is not yet on a sound footing, and that it does not receive the professional attention it deserves in a country beset by enormous social challenges. To conclude the article recommendations are made to improve the level of SIA practice in South Africa, and the possible significance of this national case study for international practice is indicated

Production bias and void swelling in the transient regime under cascade damage conditions

International Nuclear Information System (INIS)

Singh, B.N.; Foreman, A.J.E.

1992-01-01

Molecular dynamics (MD) studies of collision cascades have firmly established that, in addition to clusters of vacancies, clusters of self-interstitial atoms (SIAs) are formed within the cascade volume during the thermal spike phase of a cascade. These clusters are formed in a segregated fashion such that the vacancy-rich core is surrounded by SIA clusters. At temperatures above stage V the vacancies evaporate from the vacancy cluster and diffuse into the medium whereas the SIA clusters remain thermally stable at temperatures even above the peak swelling temperature. This asymmetry in the production of free and mobile vacancies and SIAs gives rise to a production bias. Some of the vacancies evaporating from the vacancy-rich core annihilate at the SIA clusters surrounding it and others escape into the medium. It is this escaping fraction of vacancies which determines the strength of the production bias. Diffusion calculations have been performed to estimate the magnitude of this escaping fraction of vacancies. The necessary cascade parameters for this calculation are obtained from MD simulation experiments. Almost 80% of vacancies retained in the vacancy-rich core of a 20 keV cascade are found to escape the cascade volume containing SIA clusters. We have taken this escape rate to be effective vacancy production rate in the medium and calculated the temporal evolution of SIA clusters, void size and swelling for fully annealed pure copper under neutron irradiation at 523 K. The general trends of the calculated swelling behaviour are found to be in agreement with experimental results. The present calculations provide further validity and support to the concept of production bias. (Author)

Self-organization of voids, gas bubbles and dislocation patterns under irradiation

International Nuclear Information System (INIS)

Dubinko, V.I.; Turkin, A.A.

1993-01-01

In the present paper three examples of self-organization in solids under irradiation are considered on the basis of original mechanisms, namely, the ordering of voids in void lattices under high temperature irradiation, the alignment of gas bubbles in bubble lattices under low-temperature gas atom implantation, and the formation of superdislocations (one-dimensional pile-ups of dislocation loops) and other dislocation patterns in the regimes of medium and high temperature irradiation. The ordering of cavities (i.e.voids or gas bubbles) is shown to arise due to a dissipative interaction between cavities induced by the interstitial dislocation loop absorption and punching, respectively, which represent anisotropic mechanisms of atomic transport. The dislocation patterning is shown to be driven by the dependence of dislocation bias for absorption of self-interstitial atoms on the dislocation arrangement. (author). 57 refs., 1 tab., 12 figs

Interstitial Fe in MgO

CERN Document Server

Mølholt, T E; Gunnlaugsson, H P; Svane, A; Masenda, H; Naidoo, D; Bharuth-Ram, K; Fanciulli, M; Gislason, H P; Johnston, K; Langouche, G; Ólafsson, S; Sielemann, R; Weyer, G

2014-01-01

Isolated Fe-57 atoms were studied in MgO single-crystals by emission Mossbauer spectroscopy following implantation of Mn-57 decaying to Fe-57. Four Mossbauer spectral components were found corresponding to different Fe lattice positions and/or charge states. Two components represent Fe atoms substituting Mg as Fe2+ and Fe3+, respectively; a third component is due to Fe in a strongly implantation-induced disturbed region. The fourth component, which is the focus of this paper, can be assigned to Fe at an interstitial site. Comparison of its measured isomer shift with ab initio calculations suggests that the interstitial Fe is located on, or close to, the face of the rock-salt MgO structure. To harmonize such an assignment with the measured near-zero quadrupole interaction a local motion process (cage motion) of the Fe has to be stipulated. The relation of such a local motion as a starting point for long range diffusion is discussed.

Self-consistent calculation of atomic structure for mixture

International Nuclear Information System (INIS)

Meng Xujun; Bai Yun; Sun Yongsheng; Zhang Jinglin; Zong Xiaoping

2000-01-01

Based on relativistic Hartree-Fock-Slater self-consistent average atomic model, atomic structure for mixture is studied by summing up component volumes in mixture. Algorithmic procedure for solving both the group of Thomas-Fermi equations and the self-consistent atomic structure is presented in detail, and, some numerical results are discussed

Ballistic self-annealing during ion implantation

International Nuclear Information System (INIS)

Prins, Johan F.

2001-01-01

Ion implantation conditions are considered during which the energy, dissipated in the collision cascades, is low enough to ensure that the defects, which are generated during these collisions, consist primarily of vacancies and interstitial atoms. It is proposed that ballistic self-annealing is possible when the point defect density becomes high enough, provided that none, or very few, of the interstitial atoms escape from the layer being implanted. Under these conditions, the fraction of ballistic atoms, generated within the collision cascades from substitutional sites, decreases with increasing ion dose. Furthermore, the fraction of ballistic atoms, which finally end up within vacancies, increases with increasing vacancy density. Provided the crystal structure does not collapse, a damage threshold should be approached where just as many atoms are knocked out of substitutional sites as the number of ballistic atoms that fall back into vacancies. Under these conditions, the average point defect density should approach saturation. This model is applied to recently published Raman data that have been measured on a 3 MeV He + -ion implanted diamond (Orwa et al 2000 Phys. Rev. B 62 5461). The conclusion is reached that this ballistic self-annealing model describes the latter data better than a model in which it is assumed that the saturation in radiation damage is caused by amorphization of the implanted layer. (author)

Microstructures and phase transformations in interstitial alloys of tantalum

International Nuclear Information System (INIS)

Dahmen, U.

1979-01-01

The analysis of microstructures, phases, and possible ordering of interstitial solute atoms is fundamental to an understanding of the properties of metal-interstitial alloys in general. As evidenced by the controversies on phase transformations in the particular system tantalum--carbon, our understanding of this class of alloys is inferior to our knowledge of substitutional metal alloys. An experimental clarification of these controversies in tantalum was made. Using advanced techniques of electron microscopy and ultrahigh vacuum techology, an understanding of the microstructures and phase transformations in dilute interstitial tantalum--carbon alloys is developed. Through a number of control experiments, the role and sources of interstitial contamination in the alloy preparation (and under operating conditions) are revealed. It is demonstrated that all previously published work on the dilute interstitially ordered phase Ta 64 C can be explained consistently in terms of ordering of the interstitial contaminants oxygen and hydrogen, leading to the formation of the phases Ta 12 O and Ta 2 H

Evidence of interstitial microsegregation in iron obtained by ion microscopy

International Nuclear Information System (INIS)

Price, C.W.

1984-01-01

Segregation of impurity atoms to the strain fields of dislocations and the effective locking of the dislocations by the impurity atmospheres have been suggested earlier by others. The formation of interstitial atmospheres and their effect in iron was first treated mathematically by Cottrell and Bilby (Proc. Phys. Soc.; A62: 49(1949). Hirth and Lothe (Theory of Discolations, McGraw-Hill, New York (1968) reviewed more recent evidence of interstitial effects and theoretical treatments of interstitial dislocation interactions. This paper describes additional evidence of microsegregation of several interstitial elements in iron that were detected using secondary-ion mass spectroscopy (SIMS). 10 references, 2 figures

Molecular dynamics study of interstitial-solute interactions in irradiated alloys

International Nuclear Information System (INIS)

Lam, N.Q.; Doan, N.V.; Adda, Y.

1980-01-01

The molecular dynamics technique has been used, in conjunction with the interionic potentials of Dagens et al, to study the stability, configuration, binding, and induced migration of mixed dumbbells in an irradiated Al-Zn alloy. For the purpose of comparisons, self-interstitials in pure Al were also investigated. The Al-Al and Al-Zn interactions were described by pair potentials which extended to ninth-neighbour distances. Both the self-interstitial dumbbell and the mixed dumbbell were found to be stable in the configuration. The formation energy of the self-interstitial is 2.89 eV and the mixed-dumbbell binding energy is 0.38 eV. As a result of this strong binding, the threshold energy required to induce the migration of the mixed dumbbell is about 1.2 eV, which is significantly larger than the minimum energy of about 0.15 eV transferred to a self-interstitial to induce its jumps in pure Al. Caging motions of the mixed dumbbell were observed. The present computer-simulation results are compared with experimental measurements. (author)

Social anxiety in the general population: introducing abbreviated versions of SIAS and SPS.

Science.gov (United States)

Kupper, Nina; Denollet, Johan

2012-01-01

Social anxiety is characterized by the experience of stress, discomfort and fear in social situations, and is associated with substantial personal and societal burden. Two questionnaires exist that assess the aspects of social anxiety, i.e. social interaction anxiety (SIAS) and social phobia (SPS). There is no agreement in literature on the dimensionality of social anxiety. Further, the length of a questionnaire may negatively affect response rates and participation at follow-up occasions. To explore the structure of social anxiety in the general population, and to examine psychosocial and sociodemographic correlates. Our second aim was to construct abbreviated versions of SIAS and SPS that can be easily used and with minimal burden. A total of 1598 adults from the general Dutch population completed a survey asking information on social anxiety, mood and demographics. Exploratory and confirmatory factor analyses as well as reliability analysis with item-total statistics were performed. Confirmatory factor analysis revealed a 3-factor structure for social phobia, and a 2-factor structure for the SIAS, with the second factor containing both reversely scored items. The abbreviated versions of SPS (11 items) and SIAS (10 items) show excellent discriminant and construct validity (Cronbach's α=.90 and .92), while specificity analysis showed that gender, marital status and educational level (SIAS(10): pSIAS, reducing the questionnaire burden for participants in epidemiological and biobehavioral research. Copyright © 2011 Elsevier B.V. All rights reserved.

Interaction of helium atoms with edge dislocations in α-Fe

International Nuclear Information System (INIS)

Heinisch, H.L.; Gao, F.; Kurtz, R.J.; Le, E.A.

2006-01-01

Formation energies, binding energies, and migration energies of interstitial He atoms in and near the core of an a/2 {1 1 0} edge dislocation in α-Fe are determined in atomistic simulations using conjugate gradient relaxation and the Dimer method for determining saddle point energies. Results are compared as a function of the proximity of the He to the dislocation core and the excess interstitial volume in regions around the dislocation. Interstitial He atoms have negative binding energy on the compression side of the dislocation and strong positive binding energy on the tension side. Even at low temperatures, interstitial He atoms in the vicinity of the dislocation easily migrate to the dislocation core, where they form crowdion interstitials oriented along the close-packed slip direction, with binding energies in excess of 2 eV. Crowdion interstitial He atoms diffuse along the dislocation core, transverse to the crowdion direction, with a migration energy of 0.4-0.5 eV

Modeling injected interstitial effects on void swelling in self-ion irradiation experiments

Energy Technology Data Exchange (ETDEWEB)

Short, M.P., E-mail: hereiam@mit.edu [Dept. of Nuclear Science and Engineering, Massachusetts Institute of Technology (United States); Gaston, D.R. [Idaho National Laboratory (United States); Jin, M. [Dept. of Nuclear Science and Engineering, Massachusetts Institute of Technology (United States); Shao, L. [Dept. of Nuclear Engineering, Texas A& M University (United States); Garner, F.A. [Radiation Effects Consulting, LLC (United States)

2016-04-01

Heavy ion irradiations at high dose rates are often used to simulate slow and expensive neutron irradiation experiments. However, many differences in the resultant modes of damage arise due to unique aspects of heavy ion irradiation. One such difference was recently shown in pure iron to manifest itself as a double peak in void swelling, with both peaks located away from the region of highest displacement damage. In other cases involving a variety of ferritic alloys there is often only a single peak in swelling vs. depth that is located very near the ion-incident surface. We show that these behaviors arise due to a combination of two separate effects: 1) suppression of void swelling due to injected interstitials, and 2) preferential sinking of interstitials to the ion-incident surface, which are very sensitive to the irradiation temperature and displacement rate. Care should therefore be used in collection and interpretation of data from the depth range outside the Bragg peak of ion irradiation experiments, as it is shown to be more complex than previously envisioned. - Highlights: • A model of the spatially dependent point defect kinetics equations with injected interstitials has been implemented. • The results predict a double peak in the void nucleation rate, helping to explain a recent experiment. • The double peak is predicted to be evident within a narrow (+/− 30 °C) temperature window for self-irradiation of pure iron. • The ballistic damage profile may not match the resultant void swelling profile from ion irradiation experiments.

Diffusion of interstitials in metallic systems, illustration of a complex study case: aluminum

Science.gov (United States)

David, Matthieu; Connétable, Damien

2017-11-01

While diffusion mechanisms of interstitial elements in fcc systems are generally well-known, especially in the case of H atoms, we show in this work that even in the case of a simple metallic system (aluminum), the diffusion of interstitials exhibits a wide variety of paths and mechanisms that depend on the specie. We used an approach based on first-principles calculations associated with kinetic Monte-Carlo simulations and a multi-state diffusion formalism to compute the diffusion coefficients of five interstitial elements: hydrogen, boron, carbon, nitrogen and oxygen. For instance, at the atomic scale, whilst we find that C atoms prefer to be located in octahedral sites (labeled o) rather than in tetrahedral positions (labeled t), we find one additional stable position in the lattice (M). The diffusion through these three stable positions are thus studied in detail. In the case of B atoms, for which the tetrahedral site is found unstable, the diffusion path is between o-o sites. Similarly, in the case of oxygen, t positions are found to be the only stable positions (o are unstable) and the path of migration, along t-t direction, is found through a twice degenerated asymmetric transition state. In the case of H and N atoms for which t and o sites are stable, we explain why the only path is along the t-o direction. Finally, we discuss explicit formulas to compute coefficients of diffusion of interstitials in fcc structures.

Evolution of anisotropy in bcc Fe distorted by interstitial boron

Science.gov (United States)

Gölden, Dominik; Zhang, Hongbin; Radulov, Iliya; Dirba, Imants; Komissinskiy, Philipp; Hildebrandt, Erwin; Alff, Lambert

2018-01-01

The evolution of magnetic anisotropy in bcc Fe as a function of interstitial boron atoms was investigated in thin films grown by molecular beam epitaxy. The thermodynamic nonequilibrium conditions during film growth allowed one to stabilize an interstitial boron content of about 14 at .% accompanied by lattice tetragonalization. The c /a ratio scaled linearly with the boron content up to a maximum value of 1.05 at 300 °C substrate growth temperature, with a room-temperature magnetization of. In contrast to nitrogen interstitials, the magnetic easy axis remained in-plane with an anisotropy of approximately -5.1 ×106erg /cm3 . Density functional theory calculations using the measured lattice parameters confirm this value and show that boron local ordering indeed favors in-plane magnetization. Given the increased temperature stability of boron interstitials as compared to nitrogen interstitials, this study will help to find possible ways to manipulate boron interstitials into a more favorable local order.

The annealing of interstitial carbon atoms in high-resistivity n-type silicon after proton irradiation

CERN Document Server

Kuhnke, M; Lindström, G

2002-01-01

The annealing of interstitial carbon C sub i after 7-10 MeV and 23 GeV proton irradiations at room temperature in high-resistivity n-type silicon is investigated. Deep level transient spectroscopy is used to determine the defect parameters. The annealing characteristics of the impurity defects C sub i , C sub i C sub s , C sub i O sub i and VO sub i suggest that the mobile C sub i atoms are also captured at divacancy VV sites at the cluster peripheries and not only at C sub s and O sub i sites in the silicon bulk. The deviation of the electrical filling characteristic of C sub i from the characteristic of a homogeneously distributed defect can be explained by an aggregation of C sub i atoms in the environment of the clusters. The capture rate of electrons into defects located in the cluster environment is reduced due to a positive space charge region surrounding the negatively charged cluster core. The optical filling characteristic of C sub i suggests that the change of the triangle-shaped electric field dis...

Hydrogen solution in tetrahedral or octahedral interstitial sites in Al

International Nuclear Information System (INIS)

Zeng, C.A.; Hu, J.P.; Ouyang, C.Y.

2011-01-01

Highlights: → The physical nature of the site preference for H solution in BCC Al is revealed. → The site preference is result of competition between Al-H bonding interaction and local lattice distortion. → The Al-H bonding interaction lowers the solution energy while the local lattice distortion increases the solution energy. - Abstract: It is reported that H atoms prefer to stay at interstitial (defect) sites with larger space in most metals. However, H atom prefers to occupy tetrahedral interstitial sites (T-site) that provide smaller space than octahedral sites (O-site) in Al. This paper studied the H-Al interactions from first principles calculations. Through analysis of the H-induced electronic states and the local atomic relaxations, we show that H-Al bonding interaction is stronger for T-site H, which is in favor of the solution energy. On the other hand, larger local atomic distortion is observed around the T-site H, which increases the total energy.

TED of boron in the presence of EOR defects: the use of the theory of Ostwald ripening to calculate Si-interstitial supersaturation in the vicinity of extrinsic defects

Science.gov (United States)

Bonafos, C.; Alquier, D.; Martinez, A.; Mathiot, D.; Claverie, A.

1996-05-01

When end-of-range defects are located close to or within doping profiles they render diffusion "anomalous" by both enhancing the dopant diffusivity and trapping it, both phenomena decreasing with time. Upon annealing, these defects grow in size and their density is reduced through the emission and capture of Si-interstitial atoms by a coarsening process called Ostwald ripening. In this paper, we report on how, by coupling the Ostwald ripening theory with TEM observations of the time evolution of the dislocation loops upon annealing, quantitative information allowing the enhanced diffusivity to be understood can be extracted. Indeed, during the coarsening process, a supersaturation, {C}/{C e}, of Si self-interstitial atoms is maintained between the loops and decreases with time. The enhanced diffusivity is assumed to be linked to the evolution of this interstitial supersaturation during annealing through the interstitial component of boron diffusion. We show that C drastically decreases during the first second of the anneal to asymptotically reach a value just above the equilibrium concentration Ce. This rapid decay is precisely at the origin of the transient enhanced diffusivity of dopants in the vicinity of the loops.

Single atom self-diffusion on nickel surfaces

International Nuclear Information System (INIS)

Tung, R.T.; Graham, W.R.

1980-01-01

Results of a field ion microscope study of single atom self-diffusion on Ni(311), (331), (110), (111) and (100) planes are presented, including detailed information on the self-diffusion parameters on (311), (331), and (110) surfaces, and activation energies for diffusion on the (111), and (100) surfaces. Evidence is presented for the existence of two types of adsorption site and surface site geometry for single nickel atoms on the (111) surface. The presence of adsorbed hydrogen on the (110), (311), and (331) surfaces is shown to lower the onset temperature for self-diffusion on these planes. (orig.)

Explicit studies of the quantum theory of light interstitial diffusion

International Nuclear Information System (INIS)

Emin, D.; Baskes, M.I.; Wilson, W.D.

1978-01-01

The formalism associated with small-polaron diffusion in the high temperature semiclassical regime is generalized so as to transcend simplifications employed in developing the nonadiabatic theory. The diffusion constant is then calculated for simple models in which the metal atoms interact with each other and with the interstitial atom with two-body forces. Studies of these models not only confirm the necessity of generalizing the formalism but also yield diffusion constants whose magnitudes and temperature dependenes ar consistent with the general features of the existing data for the diffusion of hydrogen and its isotopes in bcc metals. The motion of a positive muon between interstitial positions of a metal is also investigated

Surface-structure dependence of healing radiation-damage mechanism in nanoporous tungsten

Science.gov (United States)

Duan, Guohua; Li, Xiangyan; Sun, Jingjing; Hao, Congyu; Xu, Yichun; Zhang, Yange; Liu, Wei; Liu, C. S.

2018-01-01

Under nuclear fusion environments, displacement damage in tungsten (W) is usually caused by neutrons irradiation through producing large quantities of vacancies (Vs) and self-interstitial atoms (SIAs). These defects not only affect the mechanical properties of W, but also act as the trap sites for implanted hydrogen isotopes and helium. Nano-porous (NP) W with a high fraction of free surfaces has been developed to mitigate the radiation damage. However, the mechanism of the surface reducing defects accumulation is not well understood. By using multi-scale simulation methods, we investigated the interaction of the SIA and V with different surfaces on across length and time scales. We found that, at a typical operation temperature of 1000 K, surface (1 1 0) preferentially heals radiation damage of W compared with surface (1 0 0) and boundary (3 1 0). On surface (1 1 0), the diffusion barrier for the SIA is only 0.68 eV. The annihilation of the SIA-V happens via the coupled motion of the V segregation towards the surface from the bulk and the two-dimensional diffusion of the SIA on the surface. Such mechanism makes the surface (1 1 0) owe better healing capability. On surface (1 0 0), the diffusion energy barrier for the SIA is 2.48 eV, higher than the diffusion energy barrier of the V in bulk. The annihilation of the SIA-V occurs via the V segregation and recombination. The SIA was found to migrate one-dimensionally along a boundary (3 1 0) with a barrier of 0.21 eV, leading to a lower healing efficiency in the boundary. This study suggested that the on-surface process plays an important role in healing radiation damage of NP W in addition to surface-enhanced diffusion and annihilation near the surface. A certain surface structure renders nano-structured W more radiation-tolerant.

Breakthrough in Understanding Radiation Growth of Zirconiu

Energy Technology Data Exchange (ETDEWEB)

Golubov, Stanislav I [ORNL; Barashev, Alexander V [ORNL; Stoller, Roger E [ORNL; Singh, Bachu [Riso National Laboratory, Roskilde, Denmark

2014-01-01

The efforts of many scientists for more than a half of a century have resulted in a substantial understanding of the response of Zr-based materials to irradiation. However, the models of radiation growth proposed to date have not played a decisive role in creating radiation-resistant materials and cannot predict strain rates at high irradiation doses. The main reason for this is the common assumption that, regardless of the incident particle mass and energy, the primary damage consists of single vacancies and self-interstitial atoms (SIAs), both diffusing three-dimensionally. Thus, the models ignore the distinguishing features of the damage production in displacement cascades during fastparticle, e.g., neutron, irradiation; namely, the intra-cascade clustering of vacancies and SIAs and one-dimensional diffusion of SIA clusters. Over the last twenty years or so, the production bias model (PBM) has been developed, which accounts for these features and explains many observations in cubic crystals. The cascades in hcp crystals are found to be similar to those in cubic crystals; hence one can expect that the PBM will provide a realistic framework for the hcp metals as well. It is shown in this paper that it reproduces all the growth stages observed in annealed materials under neutron irradiation, such as the high strain rate at low, strain saturation at intermediate, and breakaway growth at relatively high doses. It accounts for the striking observations of negative strains in prismatic directions and co-existence of vacancy- and interstitial-type prismatic loops, which have never been explained before. It reveals the role of cold work in the radiation growth behavior and the reasons for the alignment of basal vacancy-type loops along the basal planes. The critical parameters determining the high-dose behavior are revealed and the maximum growth rate is estimated.

First-principles studies on vacancy-modified interstitial diffusion mechanism of oxygen in nickel, associated with large-scale atomic simulation techniques

International Nuclear Information System (INIS)

Fang, H. Z.; Shang, S. L.; Wang, Y.; Liu, Z. K.; Alfonso, D.; Alman, D. E.; Shin, Y. K.; Zou, C. Y.; Duin, A. C. T. van; Lei, Y. K.; Wang, G. F.

2014-01-01

This paper is concerned with the prediction of oxygen diffusivities in fcc nickel from first-principles calculations and large-scale atomic simulations. Considering only the interstitial octahedral to tetrahedral to octahedral minimum energy pathway for oxygen diffusion in fcc lattice, greatly underestimates the migration barrier and overestimates the diffusivities by several orders of magnitude. The results indicate that vacancies in the Ni-lattice significantly impact the migration barrier of oxygen in nickel. Incorporation of the effect of vacancies results in predicted diffusivities consistent with available experimental data. First-principles calculations show that at high temperatures the vacancy concentration is comparable to the oxygen solubility, and there is a strong binding energy and a redistribution of charge density between the oxygen atom and vacancy. Consequently, there is a strong attraction between the oxygen and vacancy in the Ni lattice, which impacts diffusion

Self-consistent collisional-radiative model for hydrogen atoms: Atom–atom interaction and radiation transport

International Nuclear Information System (INIS)

Colonna, G.; Pietanza, L.D.; D’Ammando, G.

2012-01-01

Graphical abstract: Self-consistent coupling between radiation, state-to-state kinetics, electron kinetics and fluid dynamics. Highlight: ► A CR model of shock-wave in hydrogen plasma has been presented. ► All equations have been coupled self-consistently. ► Non-equilibrium electron and level distributions are obtained. ► The results show non-local effects and non-equilibrium radiation. - Abstract: A collisional-radiative model for hydrogen atom, coupled self-consistently with the Boltzmann equation for free electrons, has been applied to model a shock tube. The kinetic model has been completed considering atom–atom collisions and the vibrational kinetics of the ground state of hydrogen molecules. The atomic level kinetics has been also coupled with a radiative transport equation to determine the effective adsorption and emission coefficients and non-local energy transfer.

Semiconductor studies by radioactive probe atoms

International Nuclear Information System (INIS)

Wichert, Thomas

2003-01-01

There are a growing number of experimental techniques that have in common the usage of radioactive isotopes for the characterization of semiconductors. These techniques deliver atomistic information about identity, formation, lattice environment, and electronic structure, as well as dynamics of defects and defect complexes. The results obtained by different hyperfine techniques are discussed in context with the study of intrinsic and extrinsic defects, i.e. of vacancies or self-interstitials and dopant or impurity atoms, respectively. In addition, the employment of electrical and optical techniques in combination with radioactive isotopes is presented

The energy and stability of helium-related cluster in nickel: A study of molecular dynamics simulation

Energy Technology Data Exchange (ETDEWEB)

Gong, Hengfeng, E-mail: gonghengfeng@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Division of Nuclear Materials and Engineering, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Wang, Chengbin; Zhang, Wei; Xu, Jian [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Division of Nuclear Materials and Engineering, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Huai, Ping, E-mail: huaiping@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Division of Nuclear Materials and Engineering, Shanghai 201800 (China); Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Deng, Huiqiu; Hu, Wangyu [Hunan University, Department of Applied Physics, Changsha 410082 (China)

2016-02-01

Highlights: • The He-related clusters exhibit the very high symmetry. • The trapping capability of vacancy to defects becomes weak due to the pre-existed SIA. • The average length of He{sub N}V{sub 1} clusters is longer than one of He{sub N} and He{sub N}V{sub 1}SIA{sub 1} cluster. - Abstract: Using molecular dynamics simulation, we investigated the energy and stability of helium-related cluster in nickel. All the binding energies of the He-related clusters are demonstrated to be positive and increase with the cluster sizes. Due to the pre-existed self-interstitial nickel atom, the trapping capability of vacancy to defects becomes weak. Besides, the minimum energy configurations of He-related clusters exhibit the very high symmetry in the local atomistic environment. And for the He{sub N} and He{sub N}V{sub 1}SIA{sub 1} clusters, the average length of He–He bonds shortens, but it elongates for the He{sub N}V{sub 1} clusters with helium cluster sizes. The helium-to-vacancy ratio plays a decisive role on the binding energies of He{sub N}V{sub M} cluster. These results can provide some excellent clues to insight the initial stage of helium bubbles nucleation and growth in the Ni-based alloys for the Generation-IV Molten Salt Reactor.

Theory of the change of elastic constants by interstitials

International Nuclear Information System (INIS)

Breuer, N.; Dederichs, P.H.; Lehmann, C.; Leibfried, G.; Scholz, A.

1975-01-01

The theory of the change of elastic constants by point-defects, in particular by interstitials, is briefly summarized. The typical effects of spring changes in a defect lattice on the elastic data are discussed qualitatively. Numerical results for the change of elastic constants by self-interstitials and vacancies are given and compared with experimental data for Cu and Al

Analytical relativistic self-consistent-field calculations for atoms

International Nuclear Information System (INIS)

Barthelat, J.C.; Pelissier, M.; Durand, P.

1980-01-01

A new second-order representation of the Dirac equation is presented. This representation which is exact for a hydrogen atom is applied to approximate analytical self-consistent-field calculations for atoms. Results are given for the rare-gas atoms from helium to radon and for lead. The results compare favorably with numerical Dirac-Hartree-Fock solutions

Diffuse neutron scattering study of metallic interstitial solid solutions

International Nuclear Information System (INIS)

Barberis, P.

1991-10-01

We studied two interstitial solid solutions (Ni-C(1at%) and Nb-O(2at%) and two stabilized zirconia (ZrO2-CaO(13.6mol%) and ZrO2-Y2O3(9.6mol%) by elastic diffuse neutron scattering. We used polarized neutron scattering in the case of the ferromagnetic Ni-based sample, in order to determine the magnetic perturbation induced by the C atoms. Measurements were made on single crystals in the Laboratoire Leon Brillouin (CEA-CNRS, Saclay, France). An original algorithm to deconvolve time-of-flight spectra improved the separation between elastically and inelastically scattered intensities. In the case of metallic solutions, we used a simple non-linear model, assuming that interstitials are isolated and located in octahedral sites. Results are: - in both compounds, nearest neighbours are widely displaced away from the interstitial, while next nearest neighbours come slightly closer. - the large magnetic perturbation induced by carbon in Nickel decreases with increasing distance on the three first neighbour shells and is in good agreement with the total magnetization variation. - no chemical order between solute atoms could be evidenced. Stabilized zirconia exhibit a strong correlation between chemical order and the large displacements around vacancies and dopants. (Author). 132 refs., 38 figs., 13 tabs

Ab initio theory of noble gas atoms in bcc transition metals.

Science.gov (United States)

Jiang, Chao; Zhang, Yongfeng; Gao, Yipeng; Gan, Jian

2018-06-18

Systematic ab initio calculations based on density functional theory have been performed to gain fundamental understanding of the interactions between noble gas atoms (He, Ne, Ar and Kr) and bcc transition metals in groups 5B (V, Nb and Ta), 6B (Cr, Mo and W) and 8B (Fe). Our charge density analysis indicates that the strong polarization of nearest-neighbor metal atoms by noble gas interstitials is the electronic origin of their high formation energies. Such polarization becomes more significant with an increasing gas atom size and interstitial charge density in the host bcc metal, which explains the similar trend followed by the unrelaxed formation energies of noble gas interstitials. Upon allowing for local relaxation, nearby metal atoms move farther away from gas interstitials in order to decrease polarization, albeit at the expense of increasing the elastic strain energy. Such atomic relaxation is found to play an important role in governing both the energetics and site preference of noble gas atoms in bcc metals. Our most notable finding is that the fully relaxed formation energies of noble gas interstitials are strongly correlated with the elastic shear modulus of the bcc metal, and the physical origin of this unexpected correlation has been elucidated by our theoretical analysis based on the effective-medium theory. The kinetic behavior of noble gas atoms and their interaction with pre-existing vacancies in bcc transition metals have also been discussed in this work.

Time scales of transient enhanced diffusion: Free and clustered interstitials

Science.gov (United States)

Cowern, N. E. B.; Huizing, H. G. A.; Stolk, P. A.; Visser, C. C. G.; de Kruif, R. C. M.; Kyllesbech Larsen, K.; Privitera, V.; Nanver, L. K.; Crans, W.

1996-12-01

Transient enhanced diffusion (TED) and electrical activation after nonamorphizing Si implantations into lightly B-doped Si multilayers shows two distinct timescales, each related to a different class of interstitial defect. At 700°C, ultrafast TED occurs within the first 15 s with a B diffusivity enhancement of > 2 × 10 5. Immobile clustered B is present at low concentration levels after the ultrafast transient and persists for an extended period (˜ 10 2-10 3 s). The later phase of TED exhibits a near-constant diffusivity enhancement of ≈ 1 × 10 4, consistent with interstitial injection controlled by dissolving {113} interstitial clusters. The relative contributions of the ultrafast and regular TED regimes to the final diffusive broadening of the B profile depends on the proportion of interstitials that escape capture by {113} clusters growing within the implant damage region upon annealing. Our results explain the ultrafast TED recently observed after medium-dose B implantation. In that case there are enough B atoms to trap a large proportion of interstitials in SiB clusters, and the remaining interstitials contribute to TED without passing through an intermediate {113} defect stage. The data on the ultrafast TED pulse allows us to extract lower limits for the diffusivities of the Si interstitial ( DI > 2 × 10 -10 cm 2s -1) and the B interstitial(cy) defect ( DBi > 2 × 10 -13 cm 2s -1) at 700°C.

Interstitial nephritis.

Science.gov (United States)

Papper, S

1980-01-01

There are many causes of interstitial nephritis other than pyelonephritis. The term interstitial nephritis does not connote a single etiologic or pathogenetic mechanism; it rather arbitrarily places together a wider variety of renal diseases that have a predilection for early and major involvement of the renal interstitium. The prototype of acute interstitial nephritis is acute pyelonephritis. In addition, there is a drug-related acute interstitial disease that is probably of immunological nature and usually reverses with discontinuance of the offending drug. Chronic interstitial nephritis includes many diverse illnesses. Nonobstructive pyelonephritis occurs but its prevalence is debated. Analgesic abuse nephropathy is not rare and is potentially reversible. Papillary necrosis has many causes and a wide spectrum of clinical presentations. Heavy metals, such as lead, cause interstitial nephritis. Balkan nephropathy occurs in an endemic area and although not bacterial in origin is of unknown cause.

Fluctuations of electrical and mechanical properties of diamond induced by interstitial hydrogen

Science.gov (United States)

Zhuang, Chun-Qiang; Liu, Lei

2015-01-01

While experimental evidence demonstrates that the presence of hydrogen (H) impurities in diamond films plays a significant role in determining their physical properties, the small radius of the H atom makes detecting such impurities quite a challenging task. In the present work, first-principles calculations were employed to provide an insight into the effects of the interstitial hydrogen on the electrical and mechanical properties of diamond crystals at the atomic level. The migrated pathways of the interstitial hydrogen are dictated by energetic considerations. Some new electronic states are formed near the Fermi level. The interstitial hydrogen markedly narrows the bandgap of the diamond and weakens the diamond crystal. The obvious decrement of the critical strain clearly implies the presence of an H-induced embrittlement effect. Project supported by the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality, China (Grant No. IDHT20140504), the National Natural Science Foundation of China (Grant No. 51402009), and the Foundation for Young Scholars of Beijing University of Technology, China.

St8sia2 deficiency plus juvenile cannabis exposure in mice synergistically affect higher cognition in adulthood.

Science.gov (United States)

Tantra, Martesa; Kröcher, Tim; Papiol, Sergi; Winkler, Daniela; Röckle, Iris; Jatho, Jasmin; Burkhardt, Hannelore; Ronnenberg, Anja; Gerardy-Schahn, Rita; Ehrenreich, Hannelore; Hildebrandt, Herbert

2014-12-15

The neural cell adhesion molecule (NCAM) and its functionally linked polysialyltransferases, ST8SIA2 and ST8SIA4, are crucial for synaptic plasticity. Variations in encoding genes have been associated with mental illness. Since cannabinoids can alter NCAM polysialylation, we hypothesized that delta-9-tetrahydrocannabinol (Δ9-THC) might act as environmental 'second hit' regarding cognition of St8sia2(-/-) mice. These mice show per se minor behavioral abnormalities, consisting of reduced anxiety and mild cognitive deficits. Chronic Δ9-THC treatment of juvenile male wildtype mice (St8sia2(+/+)) (7mg/kg every other day over 3 weeks) did not appreciably affect cognition. St8sia2(-/-) mice, however, displayed a synergistic negative consequence of Δ9-THC on learning/memory, accompanied by polysialic acid-free NCAM-180 reduction in hippocampus and polysialic acid increase in dentate outer molecular layer. These synergistic effects became obvious only months after the last Δ9-THC. We conclude that juvenile cannabis exposure may cause delayed but lasting damage on cognition in subjects genetically predisposed to altered NCAM polysialylation. Copyright © 2014 Elsevier B.V. All rights reserved.

An in-situ field ion microscope study of irradiated tungsten and tungsten alloys. II. The recovery behavior in Stages I and II: experimental results. Report No. 2347

International Nuclear Information System (INIS)

Wilson, K.L.; Seidman, D.N.

1974-12-01

The low temperature FIM isochronal annealing spectrum of four different purity levels of tungsten (resistivity ratios R of 5 . 10 4 , 1.5 . 10 4 , 50 and 15), irradiated in-situ with 30 keV W + ions to a dose of 5 . 10 12 ion cm -2 at 18 K, consisted of distinct recovery peaks at approximately 38, 50, 65 and 80 K with a small amount of recovery observed up to 120 K. The spectra were essentially identical between 18 and 120 K, but a fifth group of W specimens with approximately equal to 5 began to exhibit some deviations from the standard spectrum. This result indicates that the distribution of self-interstitial atoms (SIAs) produced by the ion irradiations in the W FIM tips was such that the SIA-SIA reaction dominated the recovery behavior. The isochronal peak width at half-maximum for the 38 K long-range SIA migration peak and the Stage II peaks in pure W were shown to be approximately equal to the value predicted by a diffusion model. The isochronal recovery spectra for W--0.5 at. per cent and 3 at. per cent Re alloys were radically different from the isochronal recovery spectra of pure W. For both W--Re alloys, the amount of recovery for the long-range migration peak was suppressed, and, for the 3 at. per cent Re alloy, it was almost eliminated. High-purity W (R = 5 . 10 4 ), doped with 50-100 appm carbon, showed a 20 per cent reduction in the amount of recovery observed for the long-range migration peak at 38 K. (U.S.)

Reflexões bioéticas sobre a eutanásia a partir de caso paradigmático

OpenAIRE

Santos, Daniel Abreu; Almeida, Eduardo Robatto Plessim de; Silva, Felipe Freire da; Andrade, Layo Henrique Carvalho; Azevêdo, Leandro Anton de; Neves, Nedy Maria Branco Cerqueira

2014-01-01

Recentemente, na cidade de Curitiba/PR, ocorreu um fato que gerou grande repercussão nacional e suscitou questões acerca da "eutanásia", tema controverso e pouco debatido na população em geral, o que motivou a realização deste artigo. O objetivo do trabalho consiste em analisar aspectos envolvidos no processo de morrer: eutanásia e ortotanásia e sua relação com o princípio bioético da autonomia. Trata-se de revisão reflexiva de literatura tendo como base matéria publicada na imprensa, abordan...

In-situ analysis of redistribution of carbon and nitrogen during tempering of low interstitial martensitic stainless steel

DEFF Research Database (Denmark)

Niessen, F.; Villa, M.; Danoix, F.

2018-01-01

The redistribution of C and N during tempering of X4CrNiMo16-5-1 martensitic stainless steel containing 0.034 wt% C and 0.032 wt% N was studied using in-situ synchrotron X-ray diffraction (XRD) and atom probe tomography (APT). The unit cell volume of martensite decreased continuously during...... tempering. APT showed that this volume decrease is accounted entirely for by segregation of the interstitial atoms, implying that in low interstitial martensitic stainless steel stress relaxation only contributes negligibly to changes in the martensite unit cell volume....

The thermodynamic and kinetic interactions of He interstitial clusters with bubbles in W

Energy Technology Data Exchange (ETDEWEB)

Perez, Danny, E-mail: danny-perez@lanl.gov; Sandoval, Luis; Voter, Arthur F. [Theoretical Division T-1, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Uberuaga, Blas P. [Materials Science and Technology MST-8, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2016-05-28

Due to its enviable properties, tungsten is a leading candidate plasma facing material in nuclear fusion reactors. However, like many other metals, tungsten is known to be affected by the high doses of helium atoms incoming from the plasma. Indeed, the implanted interstitial helium atoms cluster together and, upon reaching a critical cluster size, convert into substitutional nanoscale He bubbles. These bubbles then grow by absorbing further interstitial clusters from the matrix. This process can lead to deleterious changes in microstructure, degradation of mechanical properties, and contamination of the plasma. In order to better understand the growth process, we use traditional and accelerated molecular dynamics simulations to investigate the interactions between interstitial He clusters and pre-existing bubbles. These interactions are characterized in terms of thermodynamics and kinetics. We show that the proximity of the bubble leads to an enhancement of the trap mutation rate and, consequently, to the nucleation of satellite bubbles in the neighborhood of existing ones. We also uncover a number of mechanisms that can lead to the subsequent annihilation of such satellite nanobubbles.

Self-excitation of Rydberg atoms at a metal surface

DEFF Research Database (Denmark)

Bordo, Vladimir

2017-01-01

The novel effect of self-excitation of an atomic beam propagating above a metal surface is predicted and a theory is developed. Its underlying mechanism is positive feedback provided by the reflective surface for the atomic polarization. Under certain conditions the atomic beam flying in the near...... field of the metal surface acts as an active device that supports sustained atomic dipole oscillations, which generate, in their turn, an electromagnetic field. This phenomenon does not exploit stimulated emission and therefore does not require population inversion in atoms. An experiment with Rydberg...... atoms in which this effect should be most pronounced is proposed and the necessary estimates are given....

Quantum diffusion of light interstitials in metals

International Nuclear Information System (INIS)

McMullen, T.; Bergersen, B.

1978-01-01

A quantum theory of diffusion of self-trapped light interstitials in metals is presented. The theory encompasses both coherent and incoherent tunneling, but the approximation used neglects the dependence of the interstitial transfer matrix element on the vibrational state of the crystal. The coherent tunneling contribution is estimated by fitting the incoherent diffusion rate to experimental data for hydrogen and muon diffusion. It is predicted that coherent diffusion should be dominant below approximately 80 K for H in Nb and below approximately 190 K for μ + in Cu. Experimental verifications of these predictions would require high purity strain free samples and low concentrations of the diffusing species. (author)

Comparative study of displacement cascades simulated with ‘magnetic’ potentials and Mendelev-type potential in α-Fe

Energy Technology Data Exchange (ETDEWEB)

Gao, Chan, E-mail: gaochan@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); School of Graduate, China Academy of Engineering Physics, Mianyang 621900 (China); Tian, Dongfeng [China Academy of Engineering Physics, Mianyang 621900 (China); Li, Maosheng [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Qian, Dazhi [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China)

2017-04-15

Different interatomic potentials produce displacement cascades with different features, and hence they significantly influence the results obtained from the displacement cascade simulations. The displacement cascade simulations in α-Fe have been carried out by molecular dynamics with three ‘magnetic’ potentials (MP) and Mendelev-type potential in this paper. Prior to the cascade simulations, the ‘magnetic’ potentials are hardened to suit for cascade simulations. We find that the peak time, maximum of defects, cascade volume and cascade density with ‘magnetic’ potentials are smaller than those with Mendelev-type potential. There is no significant difference within statistical uncertainty in the defect production efficiency with Mendelev-type potential and the second ‘magnetic’ potential at the same cascade energy, but remarkably smaller than those with the first and third ‘magnetic’ potential. Self interstitial atom (SIA) clustered fractions with ‘magnetic’ potentials are smaller than that with Mendelev-type potential, especially at the higher energy, due to the larger interstitial formation energies which result from the ‘magnetic’ potentials. The defect clustered fractions, which are input data for radiation damage accumulation models, may influence the prediction of microstructural evolution under radiation.

Role of elasticity forces in thermodynamics of intercalation compounds : Self-consistent mean-field theory and Monte Carlo simulations

NARCIS (Netherlands)

Kalikmanov, V.I.; De Leeuw, S.W.

2002-01-01

We propose a self-consistent mean-field lattice-gas theory of intercalation compounds based on effective interactions between interstitials in the presence of the host atoms. In addition to short-range screened Coulomb repulsions, usually discussed in the lattice gas models, the present theory takes

Proceedings of the CanSIA solar conference 2008

International Nuclear Information System (INIS)

2008-01-01

The Canadian Solar Industries Association (CanSIA) promotes activities directed at improving and accelerating the widespread use of solar energy in Canada. It works to strengthen the Canadian solar industry by ensuring that governments in Canada understand the contribution that a viable solar equipment industrial base can make to Canada's industrial and social development. CanSIA helps its members in the development of product standards and building codes for the solar equipment industry, with special emphasis of safety, performance, and economic impact. The first session of the conference discussed the legal, financial and technical issues involved in capturing and capitalizing on the carbon emission reduction potential of solar projects. The second session addressed community buying issues with particular reference to matching homeowner and industry interests. Some presentations highlighted the research programs underway at universities and companies across Canada to identify the latest, most advanced and efficient technology that offers energy solutions. The barriers that the solar industry faces as it tries to deploy solar energy were also reviewed along with possible ways to overcome these barriers in ways that suit governments and local communities. The conference featured 20 presentations, of which 3 have been catalogued separately for inclusion in this database. tabs., figs

Excitation dependence of resonance line self-broadening at different atomic densities

OpenAIRE

Li, Hebin; Sautenkov, Vladimir A.; Rostovtsev, Yuri V.; Scully, Marlan O.

2009-01-01

We study the dipole-dipole spectral broadening of a resonance line at high atomic densities when the self-broadening dominates. The selective reflection spectrum of a weak probe beam from the interface of the cell window and rubidium vapor are recorded in the presence of a far-detuned pump beam. The excitation due to the pump reduces the self-broadening. We found that the self-broadening reduction dependence on the pump power is atomic density independent. These results provide experimental e...

Synergistic effects of interstitial impurities and radiation defects on mechanical characteristics of ferritic steels

International Nuclear Information System (INIS)

Charit, I.; Seok, C.S.; Murty, K.L.

2007-01-01

Ferritic steels are generally used in pressure vessels and various reactor support structures in light water reactors. They are known to exhibit radiation embrittlement in terms of decreased toughness and increased ductile-brittle transition temperature as a result of exposure to neutron radiation. The superimposed effects of strain aging due to interstitial impurity atoms on radiation embrittlement were considered first by Wechsler, Hall and others. Here we summarize some of our efforts on the investigation of synergistic effects between interstitial impurity atoms (IIAs) and radiation-induced point defects, which result in interesting effects at appropriate temperature and strain rate conditions. Two materials, a mild steel and a pressure vessel steel (A516 Gr.70), are evaluated using tensile and three-point bend tests

Mārketinga komunikāciju analīze uzņēmumā SIA "Adidas Baltics".

OpenAIRE

Zvīnis, Gusts Gustavs

2017-01-01

Bakalaura darba tēma ir “Mārketinga komunikāciju analīze uzņēmumā Sia “adidas Baltics” Darba mērķis ir pamatojoties uz apkopoto teorētiskās daļas informāciju par mārketinga komunikāciju veidiem un to plānošanu , analizēt uzņēmuma Sia “adidas Baltics” mārketinga komunikāciju efektivitāti Latvijas tirgū, rezultātā izstrādājot rekomendācijas uzņēmuma Sia “adidas Baltics” mārketinga komunikāciju efektivitātes palielināšanai. Bakalaura darbs sastāv no ievada, piecām nodaļām, secinājumiem un prie...

Locations of oxygen, nitrogen and carbon atoms in vanadium determined by neutron diffraction

International Nuclear Information System (INIS)

Hiraga, K.; Onozuka, T.; Hirabayashi, M.

1977-01-01

The occupation sites of oxygen, nitrogen, and carbon atoms dissolved interstitially in vanadium have been determined by means of neutron diffraction with use of single crystals of VOsub(0.032), VNsub(0.013) and VCsub(0.006). It is revealed that the interstitial atoms occupy, randomly, the octahedral sites in the b.c.c. host lattice of the three crystals. Neutron diffraction is advantageous for the present purpose, since the coherent scattering amplitudes of the solute atoms are much larger than that of the vanadium atom. (Auth.)

Small-polaron model of light atom diffusion

International Nuclear Information System (INIS)

Emin, D.

1977-01-01

A number of researchers have treated the diffusion of light interstitials in metals in strict analogy with the theory for the hopping diffusion of electrons in low-mobility insulators. In other words, these authors view the diffusion of light atoms as simply being an example of small-polaron hopping motion. In this paper the motion of a small polaron is introduced, and the mechanism of its motion is described. The experimental results are then succinctly presented. Next the physical assumptions implicit in the theory are compared with the situation which is believed to characterize the existence and motion of light interstitial atoms in metals. Concomitantly, the modifications of the small-polaron theory required in applying it to light atom diffusion are ennumerated

Recoil saturation of the self-energy in atomic systems

International Nuclear Information System (INIS)

Manson, J.R.; Ritchie, R.H.

1988-01-01

Within the framework of the general self-energy problem for the interaction of a projectile with a many-body system, we consider the dispersion force between two atoms or between a charge and an atom. Since the Born-Oppenheimer approximation is not made, this is a useful approach for exhibiting non-adiabatic effects. We find compact expressions in terms of matrix elements of operators in the atomic displacement which are not limited by multipole expansions. 7 refs

Interstitial atoms enable joint twinning and transformation induced plasticity in strong and ductile high-entropy alloys.

Science.gov (United States)

Li, Zhiming; Tasan, Cemal Cem; Springer, Hauke; Gault, Baptiste; Raabe, Dierk

2017-01-12

High-entropy alloys (HEAs) consisting of multiple principle elements provide an avenue for realizing exceptional mechanical, physical and chemical properties. We report a novel strategy for designing a new class of HEAs incorporating the additional interstitial element carbon. This results in joint activation of twinning- and transformation-induced plasticity (TWIP and TRIP) by tuning the matrix phase's instability in a metastable TRIP-assisted dual-phase HEA. Besides TWIP and TRIP, such alloys benefit from massive substitutional and interstitial solid solution strengthening as well as from the composite effect associated with its dual-phase structure. Nanosize particle formation and grain size reduction are also utilized. The new interstitial TWIP-TRIP-HEA thus unifies all metallic strengthening mechanisms in one material, leading to twice the tensile strength compared to a single-phase HEA with similar composition, yet, at identical ductility.

Stage II recovery behavior of a series of ion-irradiated platinum (gold) alloys as studied by field-ion microscopy. [0. 10, 0. 62, and 4. 0 at. percent Au and pure Pt

Energy Technology Data Exchange (ETDEWEB)

Wei, C.Y.; Seidman, D.N.

1976-11-01

Direct and visible evidence was obtained for long-range migration of self-interstitial atoms (SIAs) in Stage II of three different ion-irradiated platinum (gold) alloys. Field-ion microscope (FIM) specimens of Pt--0.10, 0.62 and 4.0 at. percent Au alloys were irradiated in-situ with 30-keV W/sup +/ or Pt/sup +/ ions at a tip temperature of 35 to 41 K at 2 x 10/sup -9/ torr. Direct observation of the surfaces of the FIM specimens during isochronal warming experiments to 100 K showed that a flux of SIAs crossed the surfaces of the specimens between 40 to 100 K. The spectrum for each alloy consisted of two recovery peaks (substages II/sub B/ and II/sub C/). The results are explained on the basis of an impurity-delayed diffusion mechanism employing a two-level trapping model. The application of this diffusion model to the isochronal recovery spectra yielded a dissociation enthalpy (DELTAh/sub li-Au//sup diss/) and an effective diffusion coefficient for each substage; for substage II/sub B/ DELTAh/sub li-Au//sup diss/ (II/sub B/) = 0.15 eV and for substage II/sub C/ DELTAh/sub li-Au//sup diss/ (II/sub C/) = 0.24 eV. A series of detailed control experiments was also performed to show that the imaging electric field had not caused the observed long-range migration of SIAs and that the observed effects were not the result of surface artifacts. 14 figures, 6 tables.

Role of interstitial atoms in the microstructure and non-linear elastic deformation behavior of Ti–Nb alloy

Energy Technology Data Exchange (ETDEWEB)

Tahara, Masaki [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Kim, Hee Young, E-mail: heeykim@ims.tsukuba.ac.jp [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Inamura, Tomonari; Hosoda, Hideki [Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Miyazaki, Shuichi, E-mail: miyazaki@ims.tsukuba.ac.jp [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); School of Materials Science and Engineering and ERI, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)

2013-11-15

Highlights: ► {110}{sub β}〈11{sup ¯}0〉{sub β} transverse type lattice modulation is confirmed in β phase. ► Nanosized modulated region (nanodomain) distributes homogeneously and randomly. ► Nanodomains act as obstacles against the long-ranged martensitic transformation. ► The origin of non-linear elastic deformation behavior is the continuous increase in lattice distortion strain of the favorable nanodomain variant during tensile deformation. -- Abstract: In order to clarify the effect of interstitial atoms on the non-linear elastic deformation behavior of the Ti–Nb alloy, the microstructure of (Ti–26Nb)–1.0O alloy was closely investigated by transmission electron microscope (TEM) and in situ X-ray diffraction (XRD) measurements. The 〈1 1 0〉{sub β}* rel rods and {1 1 1}{sub β}* rel planes were observed in a reciprocal space for the (Ti–26Nb)–1.0O alloy. Their origin was {110}{sub β}〈11{sup ¯}0〉{sub β} transverse type lattice modulation generated by oxygen atoms. Nanosized modulated domain structure (nanodomain) distributed homogeneously and randomly in the β phase and acted as obstacles for the long-ranged martensitic transformation in the (Ti–26Nb)–1.0O alloy. The non-linear elastic strain of the (Ti–26Nb)–1.0O alloy was generated by the continuous increase in lattice distortion strain of the favorable nanodomain variant during tensile deformation.

Role of interstitial atoms in the microstructure and non-linear elastic deformation behavior of Ti–Nb alloy

International Nuclear Information System (INIS)

Tahara, Masaki; Kim, Hee Young; Inamura, Tomonari; Hosoda, Hideki; Miyazaki, Shuichi

2013-01-01

Highlights: ► {110} β 〈11 ¯ 0〉 β transverse type lattice modulation is confirmed in β phase. ► Nanosized modulated region (nanodomain) distributes homogeneously and randomly. ► Nanodomains act as obstacles against the long-ranged martensitic transformation. ► The origin of non-linear elastic deformation behavior is the continuous increase in lattice distortion strain of the favorable nanodomain variant during tensile deformation. -- Abstract: In order to clarify the effect of interstitial atoms on the non-linear elastic deformation behavior of the Ti–Nb alloy, the microstructure of (Ti–26Nb)–1.0O alloy was closely investigated by transmission electron microscope (TEM) and in situ X-ray diffraction (XRD) measurements. The 〈1 1 0〉 β * rel rods and {1 1 1} β * rel planes were observed in a reciprocal space for the (Ti–26Nb)–1.0O alloy. Their origin was {110} β 〈11 ¯ 0〉 β transverse type lattice modulation generated by oxygen atoms. Nanosized modulated domain structure (nanodomain) distributed homogeneously and randomly in the β phase and acted as obstacles for the long-ranged martensitic transformation in the (Ti–26Nb)–1.0O alloy. The non-linear elastic strain of the (Ti–26Nb)–1.0O alloy was generated by the continuous increase in lattice distortion strain of the favorable nanodomain variant during tensile deformation

Cluster dynamics modeling and experimental investigation of the effect of injected interstitials

Science.gov (United States)

Michaut, B.; Jourdan, T.; Malaplate, J.; Renault-Laborne, A.; Sefta, F.; Décamps, B.

2017-12-01

The effect of injected interstitials on loop and cavity microstructures is investigated experimentally and numerically for 304L austenitic stainless steel irradiated at 450 °C with 10 MeV Fe5+ ions up to about 100 dpa. A cluster dynamics model is parametrized on experimental results obtained by transmission electron microscopy (TEM) in a region where injected interstitials can be safely neglected. It is then used to model the damage profile and study the impact of self-ion injection. Results are compared to TEM observations on cross-sections of specimens. It is shown that injected interstitials have a significant effect on cavity density and mean size, even in the sink-dominated regime. To quantitatively match the experimental data in the self-ions injected area, a variation of some parameters is necessary. We propose that the fraction of freely migrating species may vary as a function of depth. Finally, we show that simple rate theory considerations do not seem to be valid for these experimental conditions.

Critical parameters controlling irradiation swelling in beryllium

International Nuclear Information System (INIS)

Dubinko, V.I.

1995-01-01

Radiation effects in beryllium can hardly be explained within a framework of the conventional theory based on the bias concept due to elastic interaction difference (EID) between vacancies and self-interstitial atoms (SIAs) since beryllium belongs to hexagonal close-packed metals where diffusion has been shown to be anisotropic. Diffusional anisotropy difference (DAD) between point defects changes the cavity bias for their absorption and leads to dependence of the dislocation bias on the distribution of dislocations over crystallographic directions. On the other hand, the elastic interaction between point defects and cavities gives rise to the size and gas pressure dependencies of the cavity bias, resulting in new critical quantities for bubble-void transition effects at low temperature irradiation. In the present paper, we develop the concept of the critical parameters controlling irradiation swelling with account of both DAD and EID, and take care of thermal effects as well since they are of major importance for beryllium which has an anomalously low self-diffusion activation energy. Experimental data on beryllium swelling are analyzed on the basis of the present theory. (orig.)

Modeling of 1D motion of interstitial clusters in iron under HVEM irradiation

International Nuclear Information System (INIS)

Satoh, Y.; Hamaoka, T.; Matsui, H.

2007-01-01

Full text of publication follows: We examined 1D motion of interstitial clusters in Fe under electron irradiation at room temperature using high voltage electron microscopy (HVEM). We found that some impurities have essential effects on the experimental 1D motion behavior. The characteristics of experimental 1D motion were obtained as follows: 1) 1D motion appears as discrete jumps (namely, stepwise positional changes) at irregular intervals. 2) Sometimes a set of several successive jumps occurs between certain two points (back and forth motion). 3) The frequency of 1D jumps is almost proportional to the electron beam intensity, while the distribution of 1D jump distance does not change much with the intensity. Very few 1D jumps are observed with a 200 kV TEM at room temperature. 4) The distance and the frequency of 1D jumps are greatly reduced in a specimen of low purities. Taking account for effects of impurities, we propose a mechanism of the experimental 1D jumps, as follows. Small interstitial clusters are regarded to be essentially mobile as crowdion bundles. Then interstitial clusters in a stationary state are trapped by impurity atom(s), due to elastic interactions between impurities and crowdion bundle. The electron irradiation changes the cluster into a mobile state by a detrapping: for example, the impurity atom is displaced to apart from the crowdion bundle. Then the crowdion bundle makes a free 1D migration until it is trapped by another impurity atom. Because of small activation energy for 1D migration, we cannot observe the detailed 1D random walk process, but a stepwise positional change from an impurity to another impurity. The average size of interstitial clusters observed in the present experiments was around 5 nm, corresponding to a bundle of 300 crowdions. In a rough estimate assuming that an impurity atom on any crowdion in the crowdion bundle prevent the migration of the bundle, the mean free path is about 75 nm and 7.5 nm at the impurity

Influence of interstitial impurity atoms on point defect relaxation in neutron irradiated iron

International Nuclear Information System (INIS)

Weller, M.; Diehl, J.

1975-01-01

The aim of the investigation was to study the combined influence of neutron irradiation and interstitial impurities on the low temperature internal friction peaks as well as on those appearing at higher temperatures after annealing, in a more systematic manner, using irradiations at [de

The numerical multiconfiguration self-consistent field approach for atoms; Der numerische Multiconfiguration Self-Consistent Field-Ansatz fuer Atome

Energy Technology Data Exchange (ETDEWEB)

Stiehler, Johannes

1995-12-15

The dissertation uses the Multiconfiguration Self-Consistent Field Approach to specify the electronic wave function of N electron atoms in a static electrical field. It presents numerical approaches to describe the wave functions and introduces new methods to compute the numerical Fock equations. Based on results computed with an implemented computer program the universal application, flexibility and high numerical precision of the presented approach is shown. RHF results and for the first time MCSCF results for polarizabilities and hyperpolarizabilities of various states of the atoms He to Kr are discussed. In addition, an application to interpret a plasma spectrum of gallium is presented. (orig.)

Dependence of radiation damage accumulation in iron on underlying models of displacement cascades and subsequent defect migration

International Nuclear Information System (INIS)

Souidi, A.; Becquart, C.S.; Domain, C.; Terentyev, D.; Malerba, L.; Calder, A.F.; Bacon, D.J.; Stoller, R.E.; Osetsky, Yu. N.; Hou, M.

2006-01-01

Groups of displacement cascades calculated independently with different simulation models and computer codes are compared on a statistical basis. The parameters used for this comparison are the number of Frenkel pairs (FP) produced, the percentages of vacancies and self-interstitial atoms (SIAs) in clusters, the spatial extent and the aspect ratio of the vacancies and the SIAs formed in each cascade. One group of cascades was generated in the binary collision approximation (BCA) and all others by full molecular dynamics (MD). The MD results differ primarily due to the empirical interatomic potentials used and, to some extent, in code strategies. Cascades were generated in simulation boxes at different initial equilibrium temperatures. Only modest differences in the predicted numbers of FP are observed, but the other cascade parameters may differ by more than 100%. The consequences of these differences on long-term cluster growth in a radiation environment are examined by means of object kinetic Monte Carlo (OKMC) simulations. These were repeated with three different parameterizations of SIA and SIA cluster mobility. The differences encompassed low to high mobility, one- and three-dimensional migration of clusters, and complete immobility of large clusters. The OKMC evolution was followed until 0.1 dpa was reached. With the range of OKMC parameters used, cluster populations after 0.1 dpa differ by orders of magnitude. Using the groups of cascades from different sources induced no difference larger than a factor of 2 in the OKMC results. No correlation could be identified between the cascade parameters considered and the number densities of vacancies and SIAs predicted by OKMC to cluster in the long term. However, use of random point defect distributions instead of those obtained for displacement cascades as input for the OKMC modeling led to significantly different results. It is therefore suggested that although the displacement cascade characteristics considered

Diffusion and coupled fluxes in concentrated alloys under irradiation: a self-consistent mean-field approach

International Nuclear Information System (INIS)

Nastar, M.

2008-01-01

When an alloy is irradiated, atomic transport can occur through the two types of defects which are created: vacancies and interstitials. Recent developments of the self-consistent mean field (SCMF) kinetic theory could treat within the same formalism diffusion due to vacancies and interstitials in a multi-component alloy. It starts from a microscopic model of the atomic transport via vacancies and interstitials and yields the fluxes with a complete Onsager matrix of the phenomenological coefficients. The jump frequencies depend on the local environment through a 'broken bond model' such that the large range of frequencies involved in concentrated alloys is produced by a small number of thermodynamic and kinetic parameters. Kinetic correlations are accounted for through a set of time-dependent effective interactions within a non-equilibrium distribution function of the system. The different approximations of the SCMF theory recover most of the previous diffusion models. Recent improvements of the theory were to extend the multi-frequency approach usually restricted to dilute alloys to diffusion in concentrated alloys with jump frequencies depending on local concentrations and to generalize the formalism first developed for the vacancy diffusion mechanism to the more complex diffusion mechanism of the interstitial in the dumbbell configuration. (author)

Multi-functional magnesium alloys containing interstitial oxygen atoms.

Science.gov (United States)

Kang, H; Choi, H J; Kang, S W; Shin, S E; Choi, G S; Bae, D H

2016-03-15

A new class of magnesium alloys has been developed by dissolving large amounts of oxygen atoms into a magnesium lattice (Mg-O alloys). The oxygen atoms are supplied by decomposing titanium dioxide nanoparticles in a magnesium melt at 720 °C; the titanium is then completely separated out from the magnesium melt after solidification. The dissolved oxygen atoms are located at the octahedral sites of magnesium, which expand the magnesium lattice. These alloys possess ionic and metallic bonding characteristics, providing outstanding mechanical and functional properties. A Mg-O-Al casting alloy made in this fashion shows superior mechanical performance, chemical resistance to corrosion, and thermal conductivity. Furthermore, a similar Mg-O-Zn wrought alloy shows high elongation to failure (>50%) at room temperature, because the alloy plastically deforms with only multiple slips in the sub-micrometer grains (alloys are expected to open a new paradigm in commercial alloy design.

The self-breaking mechanism of atomic scale Au nanocontacts

International Nuclear Information System (INIS)

Nakazumi, Tomoka; Kiguchi, Manabu; Wada, Yasuo

2012-01-01

We have investigated the self-breaking mechanism of atomic scale Au nanocontacts at room temperature in air. In the conductance traces, we frequently observed traces showing both a 1G 0 (2e 2 /h) and 3G 0 plateaux, or only a 2G 0 plateau in the conductance regime below 3G 0 . The statistical analysis showed a negative correlation between the appearance of 1G 0 and 2G 0 peaks, and a positive correlation between 1G 0 and 3G 0 peaks. This conductance behavior suggested that the symmetric triple atomic rows changed into a symmetric single row, while the asymmetric double rows broke without changing into a symmetric single row. The regular self-breaking process can be explained by the breaking of the thermodynamically stable Au nanocontacts which were formed during the self-breaking of the contacts. (paper)

SIA "Emīla Gustava šokolāde" šokolādes kvalitāte.

OpenAIRE

Balcere, Marika

2007-01-01

Bakalaura darba tēmas nosaukums ir SIA „Emīla Gustava Šokolāde” šokolādes kvalitāte. Darba autore darba tēmu izvēlējās, jo ir strādājusi SIA „Emīla Gustava Šokolāde”, kā arī vēlējās gūt apstiprinājumu par izteikumu, ka SIA „Emīla Gustava Šokolāde” šokolāde ir ekskluzīva un izsmalcināta. Darba mērķis: iepazīties ar šokolādes kvalitāti. Darbs sastāv no divām daļām - teorētiskās un empīriskās daļas. 1. nodaļā aprakstīta šokolādes produktu attīstības vēsture. 2. nodaļā aprakstīta...

Suppression of Na interstitials in Na-F codoped ZnO

Science.gov (United States)

Huo, Wenxing; Mei, Zengxia; Tang, Aihua; Liang, Huili; Du, Xiaolong

2018-04-01

Controlling the formation of interstitial Na (Nai) self-compensating defects has been a long-term physics problem for effective Na doping in ZnO. Herein, we present an experimental approach to the suppression of Nai defects in ZnO via Na and F codoping under an oxygen-rich condition during the molecular beam epitaxy growth process. It is found that the incorporation of such large numbers of Na and F dopants (˜1020 cm-3) does not cause an obvious influence on the lattice parameters. Hall-effect measurements demonstrate that F doping efficiently raises the Fermi level (EF) of ZnO films, which is expected to make the formation energy of Nai and NaZn increase and decrease, respectively. Most of the Na atoms occupy the substitutional Zn sites, and the formation of Nai is suppressed consequently. Secondary ion mass spectrometry measurements reveal that F and Na atoms are tightly bonded together due to their strong Coulomb interaction. The enhanced deep level emission (DLE) in ZnO:Na-F is ascribed to the considerable amount of isolated Zn vacancy (VZn) defects induced by the elevated EF and the formation of neutral (" separators="| FO + - Na Zn - ) 0 complexes. On the other hand, formation of (" separators="| FO + - VZn 2 - ) - complexes in ZnO:F exhausts most of the isolated Zn vacancies, leading to the disappearance of the DLE band.

A simple and economic slide micro-immunoenzymatic (Micro-SIA test for epidemiological studies of toxoplasmosis

Directory of Open Access Journals (Sweden)

Mara Rosenzvit

1994-03-01

Full Text Available A slide micro-immunoenzymatic assay (micro-SIA to detectantibodies to non-particulate Toxoplasma gondii antigens is described. This assay allows the diagnosis of toxoplasmosis infection in about 1 hr. Twenty-four determinations can be performed per slide. Five hundred ng of antigen and 5 or 10 µl drop of each reactive are necessary per well. The clear contrast of colours obtained for negative and positive sera after the test is finished, allows direct discrimination of the results. However, it is possible to quantify the results of the reaction using a minireader. Sera dilution cutoff value, determined as themost frequent titre for the general population, is 1:100. The toxoplasma micro-SIA correlates well with indirect immunofluorescence (IIF, its sensitivity is atleast three times as much as IIF. The test has an intra and inter assay variation coefficient of 5.46 per cent and of 6.24 per cent respectively. Sera obtained at random from argentinian people were analyzed and a 56 per cent of infection was found. The main features of the Toxoplasma micro-SIA are its simplicity, sensitivity, reproducibility, and the virtual absence of background making it very suitable for screening tests.

Electron spin resonance signal from a tetra-interstitial defect in silicon

CERN Document Server

Mchedlidze, T

2003-01-01

The Si-B3 electron spin resonance (ESR) signal from agglomerates of self-interstitials was detected for the first time in hydrogen-doped float-zone-grown silicon samples subjected to annealing after electron irradiation. Previously this signal had been detected only in neutron- or proton-irradiated silicon samples. The absence of obscuring ESR peaks for the investigated samples at applied measurement conditions allowed an investigation of the hyperfine structure of the Si-B3 spectra. The analysis supports assignment of a tetra-interstitial defect as the origin of the signal.

ToSIA-A tool for sustainability impact assessment of forest-wood-chains

NARCIS (Netherlands)

Lindner, M.; Suominen, T.; Palosuo, T.; Garcia-Gonzalo, J.; Verweij, P.J.F.M.; Zudin, S.; Päivinen, R.

2010-01-01

Within the forest sector, the sustainability concept has evolved from a narrow focus on sustainable wood production to a much broader evaluation of environmental, social, and economic sustainability for whole value chains. A new software tool – ToSIA – has been developed for assessing sustainability

Starptautiskais mārketings SIA „NEW ROSME” uzņēmumā

OpenAIRE

Rodčenkova, Anastasija

2014-01-01

Atslēgas vārdi: ienākšanas veidi starptautiskā tirgū; franšīze; franšīzes metodes priekšrocības un trūkumi; Krievijas Federācijas apakšveļas tirgus. Bakalaura darbs sastāv no 66 lappusēm, neieskaitot pielikumus, 21 attēliem, 2 tabulām, 2 pielikumiem. Pētījuma procesā tika izmantoti 46 literatūras un informācijas avoti. Bakalaura darba temats ir „Franšīze kā uzņēmuma SIA „NEW ROSME” attīstības stratēģija Krievijas tirgū”. Darba mērķis ir izpētīt uzņēmuma SIA „NEW ROSME” franšīzes metodes...

Self-diffusion in isotopically enriched silicon carbide and its correlation with dopant diffusion

International Nuclear Information System (INIS)

Rueschenschmidt, K.; Bracht, H.; Stolwijk, N.A.; Laube, M.; Pensl, G.; Brandes, G.R.

2004-01-01

Diffusion of 13 C and 30 Si in silicon carbide was performed with isotopically enriched 4H- 28 Si 12 C/ nat SiC heterostructures which were grown by chemical vapor phase epitaxy. After diffusion annealing at temperatures between 2000 deg. C and 2200 deg. C the 30 Si and 13 C profiles were measured by means of secondary ion mass spectrometry. We found that the Si and C diffusivity is of the same order of magnitude but several orders of magnitude lower than earlier data reported in the literature. Both Si and C tracer diffusion coefficients are in satisfactory agreement with the native point defect contribution to self-diffusion deduced from B diffusion in SiC. This reveals that the native defect which mediates B diffusion also controls self-diffusion. Assuming that B atoms within the extended tail region of B profiles are mainly dissolved on C sites, we propose that B diffuses via the kick-out mechanism involving C interstitials. Accordingly, C diffusion should proceed mainly via C interstitials. The mechanism of Si diffusion remains unsolved but Si may diffuse via both Si vacancies and interstitials, with the preference for either species depending on the doping level

Eutanásia: novas considerações penais

OpenAIRE

Marcello Ovidio Lopes Guimarães

2009-01-01

Consiste o trabalho em tela na proposição de um estudo da eutanásia em seus variados aspectos, que se refletem em amplos e distintos setores do conhecimento humano, sejam eles filosóficos, religiosos, históricos, culturais, sociológicos, políticos e, particularmente, jurídicos. O estudo é iniciado com a noção geral sobre o tema eutanásico, procurando-se apresentar definições trazidas por autores dos mais diferentes matizes, na busca de uma definição que permita à norma legal amoldar-se ao con...

Single-atom lasing induced atomic self-trapping

International Nuclear Information System (INIS)

Salzburger, T.; Ritsch, H.

2004-01-01

We study atomic center of mass motion and field dynamics of a single-atom laser consisting of a single incoherently pumped free atom moving in an optical high-Q resonator. For sufficient pumping, the system starts lasing whenever the atom is close to a field antinode. If the field mode eigenfrequency is larger than the atomic transition frequency, the generated laser light attracts the atom to the field antinode and cools its motion. Using quantum Monte Carlo wave function simulations, we investigate this coupled atom-field dynamics including photon recoil and cavity decay. In the regime of strong coupling, the generated field shows strong nonclassical features like photon antibunching, and the atom is spatially confined and cooled to sub-Doppler temperatures. (author)

The diffuse interstitial lung disease - with emphasis in the idiopathic interstitial pneumonias

International Nuclear Information System (INIS)

Bustillo P, Jose G; Pacheco, Pedro M; Matiz, Carlos; Ojeda, Paulina; Carrillo B, Jorge A.

2003-01-01

The term diffuse interstitial lung disease, it refers to those diseases that commit the interstice basically, the space between the membrane basal epithelial and endothelial, although the damage can also commit the outlying air spaces and the vessels; the supplement is centered in the diffuse interstitial lung illness of unknown cause; well-known as idiopathic interstitial pneumonias, making emphasis in the more frequents, the pulmonary fibrosis idiopathic or cryptogenic fibrosant alveolitis

Variants of ST8SIA1 are associated with risk of developing multiple sclerosis.

Directory of Open Access Journals (Sweden)

Seema Husain

Full Text Available Multiple sclerosis (MS is an inflammatory demyelinating disease of the central nervous system of unknown etiology with both genetic and environmental factors playing a role in susceptibility. To date, the HLA DR15/DQ6 haplotype within the major histocompatibility complex on chromosome 6p, is the strongest genetic risk factor associated with MS susceptibility. Additional alleles of IL7 and IL2 have been identified as risk factors for MS with small effect. Here we present two independent studies supporting an allelic association of MS with polymorphisms in the ST8SIA1 gene, located on chromosome 12p12 and encoding ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1. The initial association was made in a single three-generation family where a single-nucleotide polymorphism (SNP rs4762896, was segregating together with HLA DR15/DQ6 in MS patients. A study of 274 family trios (affected child and both unaffected parents from Australia validated the association of ST8SIA1 in individuals with MS, showing transmission disequilibrium of the paternal alleles for three additional SNPs, namely rs704219, rs2041906, and rs1558793, with p = 0.001, p = 0.01 and p = 0.01 respectively. These findings implicate ST8SIA1 as a possible novel susceptibility gene for MS.

First-principles calculations of Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2} with hydrogen interstitial

Energy Technology Data Exchange (ETDEWEB)

Xu, Canhui [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900 (China); Zhang, Haibin, E-mail: hbzhang@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900 (China); Hu, Shuanglin; Zhou, Xiaosong; Peng, Shuming [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900 (China); Xiao, Haiyan [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, 610054 (China); Zhang, Guojun [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Research Institute of Functional Materials, Donghua University, Shanghai, 201620 (China)

2017-05-15

In this paper, the effects of hydrogen interstitial defect on the structural stability of two kinds of MAX materials (Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2}) were investigated by first-principles calculations. The results indicated that the hydrogen interstitial energetically prefers to reside at the 2Ti3Si site for Ti{sub 3}SiC{sub 2} and 3TiAl site for Ti{sub 3}AlC{sub 2}, respectively, and the latter has much lower formation energy. Both of these MAX phases are slightly hardened and the elastic anisotropy is reduced appreciably after the introduction of hydrogen interstitial. The hydrogen interstitial in Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2} leads to an electronic localization effect on the Si/Al atom and the effect is more remarkable in Ti{sub 3}AlC{sub 2}. The interlayer bonding strength of Ti{sub 3}AlC{sub 2} is more weakened by hydrogen interstitials than that of Ti{sub 3}SiC{sub 2}. As a result, the interatomic bonding between Si/Al and Ti atom layers is deteriorated and their structural stabilities degrade subsequently.

Interstitial Mo-Assisted Photovoltaic Effect in Multilayer MoSe2 Phototransistors.

Science.gov (United States)

Kim, Sunkook; Maassen, Jesse; Lee, Jiyoul; Kim, Seung Min; Han, Gyuchull; Kwon, Junyeon; Hong, Seongin; Park, Jozeph; Liu, Na; Park, Yun Chang; Omkaram, Inturu; Rhyee, Jong-Soo; Hong, Young Ki; Yoon, Youngki

2018-03-01

Thin-film transistors (TFTs) based on multilayer molybdenum diselenide (MoSe 2 ) synthesized by modified atmospheric pressure chemical vapor deposition (APCVD) exhibit outstanding photoresponsivity (103.1 A W -1 ), while it is generally believed that optical response of multilayer transition metal dichalcogenides (TMDs) is significantly limited due to their indirect bandgap and inefficient photoexcitation process. Here, the fundamental origin of such a high photoresponsivity in the synthesized multilayer MoSe 2 TFTs is sought. A unique structural characteristic of the APCVD-grown MoSe 2 is observed, in which interstitial Mo atoms exist between basal planes, unlike usual 2H phase TMDs. Density functional theory calculations and photoinduced transfer characteristics reveal that such interstitial Mo atoms form photoreactive electronic states in the bandgap. Models indicate that huge photoamplification is attributed to trapped holes in subgap states, resulting in a significant photovoltaic effect. In this study, the fundamental origin of high responsivity with synthetic MoSe 2 phototransistors is identified, suggesting a novel route to high-performance, multifunctional 2D material devices for future wearable sensor applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct identification of interstitial Mn in heavily p-type doped GaAs and evidence of its high thermal stability

CERN Document Server

Pereira, LMC; Correia, JG; Decoster, S; da Silva, MR; Araújo, JP; Vantomme, A

2011-01-01

We report on the lattice location of Mn in heavily p-type doped GaAs by means of $\\beta^{-}$-emission channeling from the decay of $^{56}$Mn. The majority of the Mn atoms substitute for Ga and up to 31% occupy the tetrahedral interstitial site with As nearest neighbors. Contrary to the general belief, we find that interstitial Mn is immobile up to 400$^{\\circ}$C, with an activation energy for diffusion of 1.7–2.3 eV. Such high thermal stability of interstitial Mn has significant implications on the strategies and prospects for achieving room temperature ferromagnetism in Ga$_{1−x}$Mn$_{x}$As.

Self-consistent assessment of Englert-Schwinger model on atomic properties

Science.gov (United States)

Lehtomäki, Jouko; Lopez-Acevedo, Olga

2017-12-01

Our manuscript investigates a self-consistent solution of the statistical atom model proposed by Berthold-Georg Englert and Julian Schwinger (the ES model) and benchmarks it against atomic Kohn-Sham and two orbital-free models of the Thomas-Fermi-Dirac (TFD)-λvW family. Results show that the ES model generally offers the same accuracy as the well-known TFD-1/5 vW model; however, the ES model corrects the failure in the Pauli potential near-nucleus region. We also point to the inability of describing low-Z atoms as the foremost concern in improving the present model.

Do Si/As ratios in growth medium affect arsenic uptake, arsenite efflux and translocation of arsenite in rice (Oryza sativa)?

Science.gov (United States)

Zhang, Min; Zhao, Quanli; Xue, Peiying; Zhang, Shijie; Li, Bowen; Liu, Wenju

2017-10-01

Silicon (Si) may decrease the uptake and accumulation of arsenic (As) in rice. However, the effects of Si/As ratios in growth medium on arsenic uptake, arsenite efflux to the external medium and translocation of arsenite in rice are currently unclear. Rice seedlings (Oryza sativa L.) were exposed to nutrient solutions with 10 μM arsenite [As(III)] or 10 μM arsenate [As(V)] to explore the influence of different silicic acid concentrations (0, 10, 100, 1000 μM) on arsenic uptake and translocation of arsenite with or without 91 μM phosphate for 24 h. Arsenic speciation was determined in nutrient solutions, roots, and shoots. In the arsenite treatments, different Si/As ratios (1:1, 10:1, 100:1) did not affect As(III) uptake by rice roots, however they did inhibit translocation of As(III) from roots to shoots significantly (P rice roots and shoots. A Si/As ratio of 100:1 reduced As(III) translocation from roots to shoots markedly without phosphate. When phosphate was supplied, As(III) translocation from roots to shoots was significantly inhibited by Si/As ratios of 10:1 and 100:1. The results indicated that in the presence of P, different silicic acid concentrations did not impact arsenite uptake and transport in rice when arsenite was supplied. However, a Si/As ratio of 100:1 inhibited As(V) uptake, as well as As(III) efflux and translocation from roots to shoots when arsenate was supplied. Copyright © 2017 Elsevier Ltd. All rights reserved.

Low temperature irradiation effects on plastic deformation in BCC metals

International Nuclear Information System (INIS)

Aono, Yasuhisa

1984-01-01

Low temperature electron beam experiment was carried out on high purity iron and molybdenum single crystals, and its effect on the plastic deformation was examined. As the characteristics of the irradiated iron below 77 K, remarkable softening occurred in all orientations. This phenomenon is based on the interaction of self interstitial atoms and screw dislocations, and the other features such as the absorption of interstitial atoms into screw dislocations and the slip on maximum shearing stress planes were shown. On the other hand, the aggregate of interstitial atoms formed by annealing showed the different plastic characteristics from those of interstitial atoms, and gave the results corresponding to respective stages of the electric resistance recovery curves. Regarding molybdenum, the transfer of its self interstitial atoms is near 40 K, therefore at 77 K, cluster is formed, and it largely affects abnormal slip, which is one of the features of the plasticity of molybdenum. The peculiar dependence of the yield stress on the crystalline orientation was shown. The property of the interaction of the aggregate of interstitial atoms formed and grown by the annealing from 77 K to 500 K with dislocations corresponded to the information of defects obtained by the X-ray research of Maeta, and the similarity to the aggregate of iron was observed. (Kako, I.)

SIA „Lattelecom Technology” darbība „DELL” produktu sadales kanālā.

OpenAIRE

Zēmele, Lāsma

2009-01-01

L. Zēmele SIA „Lattelecom Technology” darbība „DELL” produktu sadales kanālā Bakalaura darbs saturs:82 lpp, 10 tabulas, 16 attēlu un 16 pielikumu Bakalaura darbā raksturota SIA „Lattelecom Technology” darbība „DELL” produktu sadales kanālā. Darbā tiek analizēta produktu plūsma sadales kanālā, pasūtīšanas, uzglabāšanas un transportēšanas funkciju realizēšana šajā sadales kanālā, kā arī klientu apmierinātība ar uzņēmuma piedāvātajiem pakalpojumiem. Balstoties uz latviešu un ārzemj...

SIA skandaali neli patust - täna kõvemad kui 10 aastat tagasi / Jaanus Piirsalu

Index Scriptorium Estoniae

Piirsalu, Jaanus, 1973-

2005-01-01

1995. aasta oktoobris aset leidnud lindiskandaalist ja selle osalistest. Vt. samas: SIA skandaal ja järgnenud valitsuskriis; Väljavõte stenogrammist; Meelak: paljud ihkasid kohtus näha Savisaare verd

Adsorption behavior of Fe atoms on a naphthalocyanine monolayer on Ag(111) surface

Energy Technology Data Exchange (ETDEWEB)

Yan, Linghao; Wu, Rongting; Bao, Deliang; Ren, Junhai; Zhang, Yanfang; Zhang, Haigang; Huang, Li; Wang, Yeliang; Du, Shixuan; Huan, Qing; Gao, Hong-Jun

2015-05-29

Adsorption behavior of Fe atoms on a metal-free naphthalocyanine (H₂Nc) monolayer on Ag(111) surface at room temperature has been investigated using scanning tunneling microscopy combined with density functional theory (DFT) based calculations. We found that the Fe atoms adsorbed at the centers of H₂Nc molecules and formed Fe-H₂Nc complexes at low coverage. DFT calculations show that the configuration of Fe at the center of a molecule is the most stable site, in good agreement with the experimental observations. After an Fe-H₂Nc complex monolayer was formed, the extra Fe atoms self-assembled to Fe clusters of uniform size and adsorbed dispersively at the interstitial positions of Fe-H₂Nc complex monolayer. Furthermore, the H₂Nc monolayer grown on Ag(111) could be a good template to grow dispersed magnetic metal atoms and clusters at room temperature for further investigation of their magnetism-related properties.

Interstitial pregnancy: role of MRI

International Nuclear Information System (INIS)

Filhastre, M.; Lesnik, A.; Dechaud, H.; Taourel, P.

2005-01-01

We report the MRI features of two cases of interstitial pregnancy. In both cases, MRI was able to localize the ectopic pregnancy by showing a gestational structure surrounded by a thick wall in the upper part of the uterine wall separated from the endometrium by an uninterrupted junctional zone. Because US may confuse angular and interstitial pregnancies and because interstitial pregnancy has a particular evolutive course, MR imaging may play a key role in the diagnosis and management of women with interstitial pregnancy. (orig.)

Mass transfer in silicon at deposition of Ti thin films assisted by self ion irradiation

International Nuclear Information System (INIS)

Mikhalkovich, O.M.; Tashlykov, I.S.; Gusakov, V.E.

2011-01-01

In this paper a composite structure, processes of diffusion in Si, modified by means of ion-assisted deposition of coatings in conditions of a self-irradiation are discussed. Rutherford backscattering in combination with a channelling (RBS/Ch) of He + ions and computer program RUMP were applied to investigate an element composition. It is established, that coatings include atoms of metal, hydrogen, carbon, oxygen, silicon. The interstitial Si atoms, generated by radiation effect, diffuse during deposition of thin coating, both in a depth of a wafers, and in coatings. The influence of irradiation of ions Xe+ on diffusion processes in silicon are revealed. (authors)

Atomic-Scale Simulations of Cascade Overlap and Damage Evolution in Silicon Carbide

International Nuclear Information System (INIS)

Gao, Fei; Weber, William J.

2003-01-01

In a previous computer simulation experiment, the accumulation of damage in SiC from the overlap of 10 keV Si displacement cascades at 200 K was investigated, and the damage states produced following each cascade were archived for further analysis. In the present study, interstitial clustering, system energy, and volume changes are investigated as the damage states evolve due to cascade overlap. An amorphous state is achieved at a damage energy density of 27.5 eV/atom (0.28 displacements per atom). At low dose levels, most defects are produced as isolated Frenkel pairs, with a small number of defect clusters involving only 4 to 6 atoms; however, after the overlap of 5 cascades (0.0125 displacements per atom), the size and number of interstitial clusters increases with increasing dose. The average energy per atom increases linearly with increasing short-range (or chemical) disorder. The volume change exhibits two regimes of linear dependence on system energy and increases more rapidly with dose than either the energy or the disorder, which indicate a significant contribution to swelling of isolated interstitials and anti-site defects. The saturation volume change for the cascade-amorphized state in these simulations is 8.2%, which is in reasonable agreement with the experimental value of 10.8% in neutron-irradiated SiC

SIA "Baltegle" naudas plūsmas analīze un vadīšana

OpenAIRE

Jegorova, Valērija

2011-01-01

Vairākiem Latvijas uzņēmumiem ir aktuālas stabilizēšanas problēmas, kuras ietekmēja naudas plūsmas neefektīva vadīšana. Diplomdarba mērķis ir novērtēt SIA „Baltegle” naudas plūsmu un izstrādāt priekšlikumus tās optimizācijai. Pirmajā diplomdarba nodaļā apskatīta naudas plūsmas būtība, otrajā nodaļā - naudas plūsmas pārskata sagatavošanas īpatnības, trešajā nodaļā - analīzes un vadīšanas aspekti. Ceturtajā nodaļā pētīta SIA „Baltegle” saimnieciskā darbība. Piektajā nodaļā veikta uzņēmuma...

Dynamic properties of interstitial carbon and carbon-carbon pair defects in silicon

International Nuclear Information System (INIS)

Leary, P.; Jones, R.; Oeberg, S.; Torres, V.J.

1997-01-01

Interstitial carbon, C i , defects in Si exhibit a number of unexplained features. The C i defect in the neutral charge state gives rise to two almost degenerate vibrational modes at 920 and 931 cm -1 whose 2:1 absorption intensity ratio naturally suggests a trigonal defect in conflict with uniaxial stress measurements. The dicarbon, C s -C i , defect is bistable, and the energy difference between its A and B forms is surprisingly small even though the bonding is very different. In the B form appropriate to the neutral charge state, a silicon interstitial is believed to be located near a bond-centered site between two C s atoms. This must give rise to vibrational modes which involve the motion of both C atoms in apparent conflict with the results of photoluminescence experiments. We use an ab initio local density functional cluster method, AIMPRO, to calculate the structure and vibrational modes of these defects and find that the ratio of the absorption intensities of the local modes of C i is in reasonable agreement with experiment even though the structure of the defect is not trigonal. We also show that modes in the vicinity of those detected by photoluminescence for the B form of the dicarbon center involve independent movements of the two C atoms. Finally, the trends in the relative energies of the A and B forms in three charge states are investigated. copyright 1996 The American Physical Society

Sites of Au atoms in Sn crystals as determined by channeling

International Nuclear Information System (INIS)

Miller, J.W.; Gemmell, D.S.; Holland, R.E.; Poizat, J.C.; Worthington, J.N.; Loess, R.E.

1974-01-01

The position of Au atoms diffused into Sn monocrystals has been studied by channeling and backscattering of 2.5-MeV Ne ions. For equilibrium conditions at 217 0 C, Au atoms are found almost entirely in substitutional positions, so that the unusually fast diffusion of Au in Sn most likely arises from a small fraction of Au atoms migrating interstitially

Chlorambucil-Induced Acute Interstitial Pneumonitis

Directory of Open Access Journals (Sweden)

Hammad Shafqat

2014-01-01

Full Text Available Chlorambucil is an alkylating agent commonly used in treatment of chronic lymphocytic leukemia (CLL. We report a case of interstitial pneumonitis developing in an 83-year-old man 1.5 months after completing a six-month course of chlorambucil for CLL. The interstitial pneumonitis responded to therapy with prednisone. We performed a systematic review of literature and identified 13 other case reports of chlorambucil-induced pulmonary toxicity, particularly interstitial pneumonitis. No unifying risk factor could be discerned and the mechanism of injury remains unknown. In contrast, major randomized trials of chlorambucil therapy in CLL have not reported interstitial pneumonitis as an adverse effect, which may be due to the rarity of the phenomenon or due to underreporting of events occurring after completion of treatment. Clinicians should consider drug-induced interstitial pneumonitis in the differential diagnosis of a suggestive syndrome developing even after discontinuation of chlorambucil.

Diffuse x-ray scattering studies of defect reactions in electron-irradiated dilute nickel alloys

International Nuclear Information System (INIS)

Averback, R.S.; Ehrhart, P.

1984-01-01

Huang diffuse scattering was employed to study defect properties in dilute Ni-Si alloys. Ni alloys containing 1 at.% and 0.05 at.% Si were irradiated with electrons at 4.2 K and were subsequently isochronally annealed. It was found that, prior to annealing, the Frenkel-pair resistivities and self-interstitial atom configurations were the same in the alloys as in pure Ni. The independence of the Frenkel-pair resistivity to Si concentration indicates that the resistivities arising from Frenkel pairs and Si solute are linearly additive in Ni. After annealing through stage I to 85 K, the defect cluster size grew to 1.5, 2.3 and 3.0 interstitial atoms for the 1 at.% Si, 0.05 at.% Si and pure Ni specimens, respectively. These results demonstrate that self-interstitial atoms are not immobilised by single Si atoms in Ni, but rather complexes involving several Si atoms and/or two interstitial atoms are the stable defects at the end of annealing stage I. It was also observed that Si solute in Ni strongly suppresses the growth of interstitial clusters in stage II. In the 1 at.% Si alloys di-interstitials were immobilised up to temperatures between 200 and 300 K. There was no indication that Si solute reduced vacancy mobility in annealing stage III. The consequences of these results for the understanding of high-temperature radiation effects in alloys are discussed. (author)

Investigation of the self tempering effect of martensite by means of atom probe tomography

International Nuclear Information System (INIS)

Sackl, Stephanie; Clemens, Helmut; Primig, Sophie

2015-01-01

Self-tempering effects can be observed in steels with relatively high martensite start temperatures. After the formation of the first martensitic laths, carbon is able to diffuse in these laths during cooling, which can be attributed to sufficiently high temperatures. This effect cannot be observed in laths formed at lower temperatures. In steels containing up to 0.2 m.-% carbon, up to 90 % of the carbon atoms in the martensite segregate to dislocations during quenching. Due to its atomic resolution and sensitivity with respect to light elements, atom probe tomography is very well suited for the investigation of this phenomenon. In this study, the self-tempering effect in a quenched and tempered steel 42CrMo4 with a martensite start temperature of 310 C is investigated by means of atom probe tomography.

Ab initio study of Cr interactions with point defects in bcc Fe

International Nuclear Information System (INIS)

Olsson, P.; Domain, Ch.; Wallenius, J.

2008-01-01

Full text of publication follows. Ferritic martensitic steels are candidate structural materials for fast neutron reactors, and in particular high-Cr reduced-activation steels. In Fe-Cr alloys, Cr plays a major role in the radiation-induced evolution of the mechanical properties. Using ab initio calculations based on density functional theory, the properties of Cr in α-Fe have been investigated. The intrinsic point defect formation energies were found to be larger in model bcc Cr as compared to those in ferromagnetic bcc Fe. The interactions of Cr with point defects (vacancy and self interstitials) have been characterised. Single Cr atoms interact weakly with vacancies but significantly with self-interstitial atoms. Mixed interstitials of any interstitial symmetry are bound. Configurations where two Cr atoms are in nearest neighbour position are generally unfavourable in bcc Fe except when they are a part of a interstitial complex. Mixed interstitials do not have as strong directional stability as pure Fe interstitials have. The effects on the results using the atom description scheme of either the ultrasoft pseudo-potential (USPP) or the projector augmented wave (PAW) formalisms are connected to the differences in local magnetic moments that the two methods predict. As expected for the Fe-Cr system, the results obtained using the PAW method are more reliable than the ones obtained with USPP. (authors)

Dysthanasia, euthanasia, orthotanasia: the perceptions of nurses working in intensive care units and care implications Distanasia, eutanasia y ortotanasia: percepciones de los enfermeros de unidades de terapias intensiva e implicaciones en la asistencia Distanásia, eutanásia e ortotanásia: percepções dos enfermeiros de unidades de terapia intensiva e implicações na assistência

Directory of Open Access Journals (Sweden)

Chaiane Amorim Biondo

2009-10-01

,81% supieron citarlos. El fundamento para actuar profesionalmente, entre los enfermeros, no fue homogéneo y el conocimiento acerca del tema todavía es limitado. La búsqueda por la ortotanasia, los principios bioéticos y la humanización de la asistencia deberían ser fundamentos de su asistencia.Os objetivos deste estudo foram analisar as percepções dos enfermeiros que atuam em UTI de um hospital universitário, no Brasil, sobre distanásia, ortotanásia e eutanásia e caracterizar as possíveis implicações na assistência. Trata-se de pesquisa com abordagem quantitativa, aplicando-se questionário em 27 enfermeiros, após autorização do Comitê de Ética da Instituição e aceite formal dos sujeitos. Nenhum enfermeiro soube conceituar eutanásia, metade conceituou distanásia e apenas um terço a ortotanásia. Do total, 65,39% reconhecem algum desses processos em sua prática diária, 25,9% afirmam não acreditar que o enfermeiro pode contribuir sabendo desses conceitos e sua aplicabilidade, 82,36% relataram ser importante saber os princípios bioéticos, mas somente 14,81% souberam citá-los. O fundamento do agir profissional dos enfermeiros não foi homogêneo e o conhecimento acerca do tema ainda é limitado. A busca pela ortotanásia, os princípios bioéticos e a humanização da assistência deveriam ser fundamentos de sua assistência.

The numerical multiconfiguration self-consistent field approach for atoms

International Nuclear Information System (INIS)

Stiehler, Johannes

1995-12-01

The dissertation uses the Multiconfiguration Self-Consistent Field Approach to specify the electronic wave function of N electron atoms in a static electrical field. It presents numerical approaches to describe the wave functions and introduces new methods to compute the numerical Fock equations. Based on results computed with an implemented computer program the universal application, flexibility and high numerical precision of the presented approach is shown. RHF results and for the first time MCSCF results for polarizabilities and hyperpolarizabilities of various states of the atoms He to Kr are discussed. In addition, an application to interpret a plasma spectrum of gallium is presented. (orig.)

Smoking-related interstitial lung diseases

International Nuclear Information System (INIS)

Marten, K.

2007-01-01

The most important smoking-related interstitial lung diseases (ILD) are respiratory bronchiolitis, respiratory bronchiolitis-associated interstitial lung disease, desquamative interstitial pneumonia, and Langerhans' cell histiocytosis. Although traditionally considered to be discrete entities, smoking-related ILDs often coexist, thus accounting for the sometimes complex patterns encountered on high-resolution computed tomography (HRCT). Further studies are needed to elucidate the causative role of smoking in the development of pulmonary fibrosis

Comparative study of radiation damage accumulation in Cu and Fe

International Nuclear Information System (INIS)

Caturla, M.J.; Soneda, N.; Alonso, E.; Wirth, B.D.; Diaz de la Rubia, T.; Perlado, J.M.

2000-01-01

Bcc and fcc metals exhibit significant differences in behavior when exposed to neutron or heavy ion irradiation. Transmission electron microscopy (TEM) observations reveal that damage in the form of stacking fault tetrahedra (SFT) is visible in copper irradiated to very low doses, but that no damage is visible in iron irradiated to the same total dose. In order to understand and quantify this difference in behavior, we have simulated damage production and accumulation in fcc Cu and bcc Fe. We use 20 keV primary knock-on atoms (PKAs) at a homologous temperature of 0.25 of the melting point. The primary damage state was calculated using molecular dynamics (MD) with empirical, embedded-atom interatomic potentials. Damage accumulation was modeled using a kinetic Monte Carlo (kMC) algorithm to follow the evolution of all defects produced in the cascades. The diffusivities and binding energies of defects are input data for this simulation and were either extracted from experiments, the literature, or calculated using MD. MD simulations reveal that vacancy clusters are produced within the cascade core in the case of copper. In iron, most of the vacancies do not cluster during cooling of the cascade core and are available for diffusion. In addition, self-interstitial atom (SIA) clusters are produced in copper cascades but those observed in iron are smaller in number and size. The combined MD/kMC simulations reveal that the visible cluster densities obtained as a function of dose are at least one order of magnitude lower in Fe than in Cu. We compare the results with experimental measurements of cluster density and find excellent agreement between the simulations and experiments when small interstitial clusters are considered to be mobile as suggested by recent MD simulations

The Social Interaction Anxiety Scale (SIAS) and the Social Phobia Scale (SPS): a comparison of two short-form versions.

Science.gov (United States)

Fergus, Thomas A; Valentiner, David P; Kim, Hyun-Soo; McGrath, Patrick B

2014-12-01

The widespread use of Mattick and Clarke's (1998) Social Interaction Anxiety Scale (SIAS) and Social Phobia Scale (SPS) led 2 independent groups of researchers to develop short forms of these measures (Fergus, Valentiner, McGrath, Gier-Lonsway, & Kim, 2012; Peters, Sunderland, Andrews, Rapee, & Mattick, 2012). This 3-part study examined the psychometric properties of Fergus et al.'s and Peters et al.'s short forms of the SIAS and SPS using an American nonclinical adolescent sample in Study 1 (N = 98), American patient sample with an anxiety disorder in Study 2 (N = 117), and both a South Korean college student sample (N = 341) and an American college student sample (N = 550) in Study 3. Scores on both sets of short forms evidenced adequate internal consistency, interitem correlations, and measurement invariance. Scores on Fergus et al.'s short forms, particularly their SIAS short form, tended to capture more unique variance in scores of criterion measures than did scores on Peters et al.'s short forms. Implications for the use of these 2 sets of short forms are discussed. (c) 2014 APA, all rights reserved.

As viagens de Nísia Floresta: memória, testemunho e história The travels of Nísia Floresta: memory, testimony, and history

OpenAIRE

Constância Lima Duarte

2008-01-01

Dentre os escritores brasileiros do século XIX, que registraram suas viagens em livros, destaca-se Nísia Floresta Brasileira Augusta. Nascida no interior do Rio Grande do Norte, em 1810, ela residiu em Pernambuco, Rio Grande do Sul e Rio de Janeiro antes de se mudar para a Europa, em 1849, e visitar diferentes países até falecer, em 1885, em Rouen, na França. Dos 15 títulos que publicou - romance, novela, contos, poemas e ensaios, escritos em português, francês e italiano -, estão os interess...

In situ observation of thermal relaxation of interstitial-vacancy pair defects in a graphite gap.

Science.gov (United States)

Urita, Koki; Suenaga, Kazu; Sugai, Toshiki; Shinohara, Hisanori; Iijima, Sumio

2005-04-22

Direct observation of individual defects during formation and annihilation in the interlayer gap of double-wall carbon nanotubes (DWNT) is demonstrated by high-resolution transmission electron microscopy. The interlayer defects that bridge two adjacent graphen layers in DWNT are stable for a macroscopic time at the temperature below 450 K. These defects are assigned to a cluster of one or two interstitial-vacancy pairs (I-V pairs) and often disappear just after their formation at higher temperatures due to an instantaneous recombination of the interstitial atom with vacancy. Systematic observations performed at the elevated temperatures find a threshold for the defect annihilation at 450-500 K, which, indeed, corresponds to the known temperature for the Wigner energy release.

In situ observation of thermal relaxation of interstitial-vacancy pair defects in a graphite gap

International Nuclear Information System (INIS)

Urita, Koki; Suenaga, Kazu; Iijima, Sumio; Sugai, Toshiki; Shinohara, Hisanori

2005-01-01

Direct observation of individual defects during formation and annihilation in the interlayer gap of double-wall carbon nanotubes (DWNT) is demonstrated by high-resolution transmission electron microscopy. The interlayer defects that bridge two adjacent graphen layers in DWNT are stable for a macroscopic time at the temperature below 450 K. These defects are assigned to a cluster of one or two interstitial-vacancy pairs (I-V pairs) and often disappear just after their formation at higher temperatures due to an instantaneous recombination of the interstitial atom with vacancy. Systematic observations performed at the elevated temperatures find a threshold for the defect annihilation at 450-500 K, which, indeed, corresponds to the known temperature for the Wigner energy release

Atomic structure of self-organizing iridium induced nanowires on Ge(001)

Energy Technology Data Exchange (ETDEWEB)

Kabanov, N.S., E-mail: n.kabanov@utwente.nl [Faculty of Physics, Moscow State University, 119991 (Russian Federation); Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P. O. Box 217, Enschede 7500 AE (Netherlands); Heimbuch, R.; Zandvliet, H.J.W. [Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P. O. Box 217, Enschede 7500 AE (Netherlands); Saletsky, A.M.; Klavsyuk, A.L. [Faculty of Physics, Moscow State University, 119991 (Russian Federation)

2017-05-15

Highlights: • Ir/Ge(001) structure has been studied with DFT calculations and scanning tunneling microscopy. • Ir/Ge(001) nanowires are composed of Ge atoms and Ir atoms are located in subsurface positions. • The regions in the vicinity of the nanowires are very dynamic, even at temperatures as low as 77 K. - Abstract: The atomic structure of self-organizing iridium (Ir) induced nanowires on Ge(001) is studied by density functional theory (DFT) calculations and variable-temperature scanning tunneling microscopy. The Ir induced nanowires are aligned in a direction perpendicular to the Ge(001) substrate dimer rows, have a width of two atoms and are completely kink-less. Density functional theory calculations show that the Ir atoms prefer to dive into the Ge(001) substrate and push up the neighboring Ge substrate atoms. The nanowires are composed of Ge atoms and not Ir atoms as previously assumed. The regions in the vicinity of the nanowires are very dynamic, even at temperatures as low as 77 K. Time-resolved scanning tunneling microscopy measurements reveal that this dynamics is caused by buckled Ge substrate dimers that flip back and forth between their two buckled configurations.

Intracranial interstitial radiation

International Nuclear Information System (INIS)

Willis, D.; Rittenmeyer, H.; Hitchon, P.

1986-01-01

Primary malignant brain tumors are fatal, with 90% of patients having these tumors dying within two years following diagnosis. Cranial interstitial radiation therapy, a technique under investigation to control these tumors, involves implantation of radioactive iodine 125 seeds into the tumor bed by stereotaxic technique. The interstitial radiation technique, monitoring of radiation, and nursing care of patients are discussed. Case histories are presented, along with discussion of results attained using this therapy, and its future

A channeling investigation of the interaction between solute atoms and irradiation-produced defects in magnesium

International Nuclear Information System (INIS)

Howe, L.M.; Swanson, M.L.; Quenneville, A.F.

1978-01-01

The trapping of irradiation-produced defects by solute atoms in Mg crystals was monitored by measuring the displacement of the solute atoms from lattice sites using the backscattering-channeling technique. In Mg-0.2 at.% Ag crystals, irradiation at 30 K with 1 MeVHe + ions resulted in a very large fraction of Ag atoms being displaced from their lattice sites. The Ag atom displacement appeared to be along directions and is attributed to the trapping of migrating Mg interstitial atoms by Ag atoms to form Mg-Ag mixed dumbbells. Recovery of the Ag atom displacements and the irradiation-induced dechanneling increment occurred principally in two stages, 80-160 K (stage III) and 200-280 K (stage IV). Stage III is attributed mainly to some type of interstitial migration and stage IV is attributed to the migration of single vacancies. In contrast to the Mg-Ag results, a very small displaced fraction of Bi atoms occurred in an irradiated Mg-0.08 at.% Bi crystal; hence Mg-Bi mixed dumbbells do not appear to be formed. (author)

Multiconfigurational self-consistent field calculations of nuclear shieldings using London atomic orbitals

DEFF Research Database (Denmark)

Ruud, Kenneth; Helgaker, Trygve; Kobayashi, Rika

1994-01-01

to corresponding individual gauges for localized orbitals (IGLO) results. The London results show better basis set convergence than IGLO, especially for heavier atoms. It is shown that the choice of active space is crucial for determination of accurate nuclear shielding constants.......Nuclear shielding calculations are presented for multiconfigurational self-consistent field wave functions using London atomic orbitals (gauge invariant atomic orbitals). Calculations of nuclear shieldings for eight molecules (H2O, H2S, CH4, N2, CO, HF, F2, and SO2) are presented and compared...

Effect of single interstitial impurity in iron-based superconductors with sign-changed s-wave pairing symmetry

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiang-Long, E-mail: xlyu@theory.issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Liu, Da-Yong; Quan, Ya-Min; Zheng, Xiao-Jun [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Zou, Liang-Jian, E-mail: zou@theory.issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Department of Physics, University of Science and Technology of China, Hefei 230026 (China)

2015-12-15

Highlights: • Effects of single interstitial impurity are studied in iron-based superconductors. • Bound states within the superconducting gap can be induced. • The interstitial impurity can induce a π phase shift of pairing order parameter. • For strong magnetic scattering the bound-state peak can appear at the Fermi level. - Abstract: We employ the self-consistent Bogoliubov-de Gennes (BdG) formulation to investigate the effect of single interstitial nonmagnetic/magnetic impurity in iron-based superconductors with s ± -wave pairing symmetry. We find that both the nonmagnetic and magnetic impurities can induce bound states within the superconducting (SC) gap and a π phase shift of SC order parameter at the impurity site. However, different from the interstitial-nonmagnetic-impurity case characterized by two symmetric peaks with respect to zero energy, the interstitial magnetic one only induces single bound-state peak. In the strong scattering regime this peak can appear at the Fermi level, which has been observed in the recent scanning tunneling microscope (STM) experiment of Fe(Te,Se) superconductor with interstitial Fe impurities (Yin et al. 2015 [44]). This novel single in-gap peak feature also distinguishes the interstitial case from the substitutional one with two peaks. These results provide important information for comparing the different impurity effects in the iron-based superconductors.

As viagens e o discurso autobiográfico de Nísia Floresta

Directory of Open Access Journals (Sweden)

Constância Lima Duarte

2009-12-01

Full Text Available Nos livros em que registrou suas viagens pela Europa, Nísia Floresta deixou também, ao lado de reflexões sobre as novas culturas, depoimentos importantes da própria vida. Aliás, praticamente tudo o que se sabe hoje sobre a autora foi encontrado em seus livros, independente deles serem poemas, romances, crônicas ou ensaios, tal o caráter autobiográfico de sua obra. Para este momento, tratarei de um dos livros de viagem: o Itinerário de uma viagem à Alemanha, escrito em francês e publicado em Paris, em 1857. Em seu relato, Nísia Floresta vai privilegiar não a história da cidade que visita, mas a própria subjetividade, ou seja, as emoções que os objetos e os lugares lhe despertam. Através da memória, ela busca reminiscências da infância, ou vai ao encontro de familiares distantes, estejam eles vivos ou não, como forma de novamente re-viver momentos de felicidade. A narradora se coloca no centro da escritura, se auto contempla romanticamente, e tudo o mais parece girar à sua volta.

Measurement of collisional self broadening of atomic resonance lines in selective reflection experiment

International Nuclear Information System (INIS)

Papoyan, A.V.

1998-01-01

A method is developed to measure directly the collisional self broadening rate for a dense atomic vapor from selective reflection spectra. Experimental realization for the atomic D 1 and D 2 resonance lines of Rb confirms a validity of the proposed technique. The deflection of experimentally measured values is not more than 20% from theoretically predicted ones in the atomic number density range of 7· 10 16 - 7· 10 17 cm - 3 . 10 refs

First-principles studies of di-arsenic interstitial and its implications for arsenic-interstitial diffusion in crystalline silicon

International Nuclear Information System (INIS)

Kim, Yonghyun; Kirichenko, Taras A.; Kong, Ning; Larson, Larry; Banerjee, Sanjay K.

2007-01-01

We propose new structural configurations and novel diffusion mechanisms for neutral di-arsenic interstitial (As 2 I 2 ) in silicon with a first-principle density functional theory simulation within the generalized gradient approximation. With an assumption of excess silicon interstitials and high arsenic concentrations, neutral As 2 I 2 is expected to be favorable and mobile with low-migration barrier. Moreover, because the diffusion barrier of arsenic interstitial pairs (AsI) is very low ( 2 I 2 can be easily formed and likely intermediate stage of larger arsenic interstitial clusters

Interstitial irradiation for craniopharyngioma

International Nuclear Information System (INIS)

Barlas, O.; Bayindir, C.; Can, M.

2000-01-01

The results of interstitial irradiation treatment for craniopharyngioma in two patients with six year follow-ups are presented. Stereotactic interstitial irradiation with iodine-125 sources as sole therapy was employed in two adult patients who refused surgical resection. The diagnoses were confirmed by stereotactic biopsy. The first tumour which underwent interstitial irradiation was solid and 4 cm in diameter, and the second, 2.7 cm in diameter, had both cystic and solid components. The implanted iodine-125 seeds delivered 67 Gy and 60 Gy to tumour periphery at the rate of 12 and 14 cGy/h, respectively, were removed at the end of designated radiation periods. Tumour shrinkage and central hypo density, first observed 3 months after irradiation, continued until one tumour shrank to less than 1 cm at 12 months, and the other disappeared completely at 24 months. In both cases functional integrity was restored, and neither radiation induced toxicity nor recurrence has occurred six years after treatment. The results in these two cases suggest that solid craniopharyngiomas are sensitive to interstitial irradiation. (author)

Concentration dependence of solute atoms on vacancy cluster formation in neutron irradiated Ni alloy

International Nuclear Information System (INIS)

Sato, K.; Itoh, D.; Yoshiie, T.; Xu, Q.

2007-01-01

Full text of publication follows: One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. The movement of interstitial clusters was often observed in neutron irradiated metals by transmission electron microscopy (TEM). Alloying elements are expected to affect the motion of interstitial clusters. Yoshiie et al. have studied the effect of alloying elements in Ni. For example, in neutron irradiated pure Ni, well-developed dislocation networks and voids were observed at 573 K at a dose of 0.026 dpa by TEM. After the addition of 2at.%Si (-5.81% volume size factor to Ni) and Sn (74.08% volume size factor), no voids were detected by TEM observation and positron lifetime measurement. Alloying elements of Si and Sn were expected to prevent the 1-D motion of the interstitial clusters. In this study, the concentration dependence of alloying elements on the 1-D motion of the interstitial clusters was investigated by positron annihilation lifetime measurements, and the microstructural evolution was discussed. Specimens irradiated were 99.99 pure Ni (Johnson Matthey) and Ni based binary alloys, which contain Si, Cu, Ge and Sn as solute atoms. The concentration of solute atoms was 0.05at.%o, 0.3at.% and 2at.%. Neutron irradiation was performed with the Kyoto University Reactor (KUR) and Japan materials testing reactor (JMTR) at Japan Atomic Energy Agency. Neutron dose was 6x10 -5 -1x10 -2 dpa at KUR, and 8x10 -3 -0.3 dpa at JMTR. Irradiation temperature was 573 K at KUR and 563 K at JMTR. After the neutron irradiation, positron annihilation lifetime measurements were performed at room temperature. Microvoids were detected in pure Ni, Ni-0.05%Si, Ni-0.05%Sn, Ni-Cu and Ni-Ge alloys. In Ni-Si and Ni-Sn alloys, the size of microvoids decreased as the concentration of solute atoms increased. This is because the frequency of 1-D motion of the interstitial clusters depends on the alloy concentration. High concentration of alloying

Concentration dependence of solute atoms on vacancy cluster formation in neutron irradiated Ni alloy

Energy Technology Data Exchange (ETDEWEB)

Sato, K.; Itoh, D.; Yoshiie, T.; Xu, Q. [Kyoto Univ., Research Reactor Institute, Osaka (Japan)

2007-07-01

Full text of publication follows: One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. The movement of interstitial clusters was often observed in neutron irradiated metals by transmission electron microscopy (TEM). Alloying elements are expected to affect the motion of interstitial clusters. Yoshiie et al. have studied the effect of alloying elements in Ni. For example, in neutron irradiated pure Ni, well-developed dislocation networks and voids were observed at 573 K at a dose of 0.026 dpa by TEM. After the addition of 2at.%Si (-5.81% volume size factor to Ni) and Sn (74.08% volume size factor), no voids were detected by TEM observation and positron lifetime measurement. Alloying elements of Si and Sn were expected to prevent the 1-D motion of the interstitial clusters. In this study, the concentration dependence of alloying elements on the 1-D motion of the interstitial clusters was investigated by positron annihilation lifetime measurements, and the microstructural evolution was discussed. Specimens irradiated were 99.99 pure Ni (Johnson Matthey) and Ni based binary alloys, which contain Si, Cu, Ge and Sn as solute atoms. The concentration of solute atoms was 0.05at.%o, 0.3at.% and 2at.%. Neutron irradiation was performed with the Kyoto University Reactor (KUR) and Japan materials testing reactor (JMTR) at Japan Atomic Energy Agency. Neutron dose was 6x10{sup -5}-1x10{sup -2} dpa at KUR, and 8x10{sup -3} -0.3 dpa at JMTR. Irradiation temperature was 573 K at KUR and 563 K at JMTR. After the neutron irradiation, positron annihilation lifetime measurements were performed at room temperature. Microvoids were detected in pure Ni, Ni-0.05%Si, Ni-0.05%Sn, Ni-Cu and Ni-Ge alloys. In Ni-Si and Ni-Sn alloys, the size of microvoids decreased as the concentration of solute atoms increased. This is because the frequency of 1-D motion of the interstitial clusters depends on the alloy concentration. High

Interstitial-impurity interactions in copper-silver and aluminum-magnesium alloys

International Nuclear Information System (INIS)

Wong, H.P.

1982-01-01

The configurations and dynamical properties of complexes formed between interstitials and oversized impurities in electron-irradiated aluminum and copper were determined. Measurements were taken of the ultrasonic attention and resonant frequency in single crystal samples of Cu-Ag and Al-Mg. A variety of peaks appeared in both materials in plots of the logarithmic decrement versus temperature. The simultaneous presence of multiple defects was established by the different annealing behavior shown by each peak. It was found that interstitial trapping in our oversized systems was generally weaker than in previously studied undersized systems. The principal features in Cu-Ag that must be accounted for by a model include the following: (1) Three low-temperature peaks were seen having trigonal symmetry. The main peak annealed away at 110 K uncorrelated with any resistivity recovery and it grew at 60 K, correlated with a resistivity decrease. For Al-MG, the principal features associated with the main peak include: seen at high temperature (>135 K) having trigonal symmetry; annealed away at 127 K and seemed to correlate with a resistivity decrease; remaining peaks grew while the main peak annealed away. The implications of an existing model were developed. No evidence was found for the deeply-trapped -orthorhombic defect predicted by the existing model. Therefore, two alternative models were developed. Model A uses a canted dumb-bell at the next-nearest neighbor position to explain the results. Model B uses a point interstitial at an octahedral position. A distinction between the two which is subject to experimental check is that model A predicts that interstitial migration between different impurity atoms occurs near 127 K in Cu-Ag while model B predicts a migration temperature near 60 K

Interstitial Cells of Blood Vessels

Directory of Open Access Journals (Sweden)

Vladimír Pucovský

2010-01-01

Full Text Available Blood vessels are made up of several distinct cell types. Although it was originally thought that the tunica media of blood vessels was composed of a homogeneous population of fully differentiated smooth muscle cells, more recent data suggest the existence of multiple smooth muscle cell subpopulations in the vascular wall. One of the cell types contributing to this heterogeneity is the novel, irregularly shaped, noncontractile cell with thin processes, termed interstitial cell, found in the tunica media of both veins and arteries. While the principal role of interstitial cells in veins seems to be pacemaking, the role of arterial interstitial cells is less clear. This review summarises the knowledge of the functional and structural properties of vascular interstitial cells accumulated so far, offers hypotheses on their physiological role, and proposes directions for future research.

Ultralow contact resistance at an epitaxial metal/oxide heterojunction through interstitial site doping.

Science.gov (United States)

Chambers, Scott A; Gu, Meng; Sushko, Peter V; Yang, Hao; Wang, Chongmin; Browning, Nigel D

2013-08-07

Heteroepitaxial growth of Cr metal on Nb-doped SrTiO₃(001) is accompanied by Cr diffusion to interstitial sites within the first few atomic planes, an anchoring of the Cr film to the substrate, charge transfer from Cr to Ti, and metallization of the near-surface region, as depicted in the figure. The contact resistance of the resulting interface is exceedingly low. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chylothorax in dermatomyositis complicated with interstitial pneumonia.

Science.gov (United States)

Isoda, Kentaro; Kiboshi, Takao; Shoda, Takeshi

2017-04-01

Chylothorax is a disease in which chyle leaks and accumulates in the thoracic cavity. Interstitial pneumonia and pneumomediastinum are common thoracic manifestations of dermatomyositis, but chylothorax complicated with dermatomyositis is not reported. We report a case of dermatomyositis with interstitial pneumonia complicated by chylothorax. A 77-year-old woman was diagnosed as dermatomyositis with Gottron's papules, skin ulcers, anti-MDA5 antibody and rapid progressive interstitial pneumonia. Treatment with betamethasone, tacrolimus and intravenous high-dose cyclophosphamide was initiated, and her skin symptoms and interstitial pneumonia improved once. However, right-sided chylothorax began to accumulate and gradually increase, and at the same time, her interstitial pneumonia began to exacerbate, and skin ulcers began to reappear on her fingers and auricles. Although her chylothorax improved by fasting and parenteral nutrition, she died due to further exacerbations of dermatomyositis and interstitial pneumonia in spite of steroid pulse therapy, increase in the betamethasone dosage, additional intravenous high-dose cyclophosphamide and plasma pheresis. An autopsy showed no lesions such as malignant tumors in the thoracic cavity. This is the first report of chylothorax complicated by dermatomyositis with interstitial pneumonia.

He-ion and self-atom induced damage and surface-morphology changes of a hot W target

International Nuclear Information System (INIS)

Meyer, F W; Hijazi, H; Bannister, M E; Dadras, J; Krstic, P S; Meyer, H M III; Parish, C M

2014-01-01

We report results of measurements on the evolution of the surface morphology of a hot tungsten surface due to impacting low-energy (80–12 000 eV) He ions and of simulations of damage caused by cumulative bombardment of 1 and 10 keV W self-atoms. The measurements were performed at the ORNL Multicharged Ion Research Facility, while the simulations were done at the Kraken supercomputing facility of the University of Tennessee. At 1 keV, the simulations show strong defect-recombination effects that lead to a saturation of the total defect number after a few hundred impacts, while sputtering leads to an imbalance of the vacancy and interstitial number. On the experimental side, surface morphology changes were investigated over a broad range of fluences, energies and temperatures for both virgin and pre-damaged W-targets. At the lowest accumulated fluences, small surface-grain features and near-surface He bubbles are observed. At the largest fluences, individual grain characteristics disappear in focused ion beam/scanning electron microscopy (FIB/SEM) scans, and the entire surface is covered by a multitude of near-surface bubbles with a broad range of sizes, and disordered whisker growth, while in top-down SEM imaging the surface is virtually indistinguishable from the nano-fuzz produced on linear plasma devices. These features are evident at progressively lower fluences as the He-ion energy is increased. (paper)

Coupling of atom-by-atom calculations of extended defects with B kick-out equations: application to the simulation of boron ted

International Nuclear Information System (INIS)

Lampin, E.; Cristiano, F.; Lamrani, Y.; Colombeau, B.

2004-01-01

We present simulations of B TED based on a complete calculation of the extended defect growth/shrinkage during annealing. The Si self-interstitial supersaturation calculated at the extended defect depth is coupled to the set of equations for the B kick-out diffusion through a generation/recombination term in the diffusion equation of the Si self-interstitials. The simulations are compared to the measurements performed on a Si wafer containing several B marker layers, where the amount of TED varies from one peak to the other. The good agreement obtained on this experiment is very promising for the application of these calculations to the case of ultra-shallow B + implants

Experimental depletion of different renal interstitial cell populations

International Nuclear Information System (INIS)

Bohman, S.O.; Sundelin, B.; Forsum, U.; Tribukait, B.

1988-01-01

To define different populations of renal interstitial cells and investigate some aspects of their function, we studied the kidneys of normal rats and rats with hereditary diabetes insipidus (DI, Brattleboro) after experimental manipulations expected to alter the number of interstitial cells. DI rats showed an almost complete loss of interstitial cells in their renal papillae after treatment with a high dose of vasopressin. In spite of the lack of interstitial cells, the animals concentrated their urine to the same extent as vasopressin-treated normal rats, indicating that the renomedullary interstitial cells do not have an important function in concentrating the urine. The interstitial cells returned nearly to normal within 1 week off vasopressin treatment, suggesting a rapid turnover rate of these cells. To further distinguish different populations of interstitial cells, we studied the distribution of class II MHC antigen expression in the kidneys of normal and bone-marrow depleted Wistar rats. Normal rats had abundant class II antigen-positive interstitial cells in the renal cortex and outer medulla, but not in the inner medulla (papilla). Six days after 1000 rad whole body irradiation, the stainable cells were almost completely lost, but electron microscopic morphometry showed a virtually unchanged volume density of interstitial cells in the cortex and outer medulla, as well as the inner medulla. Thus, irradiation abolished the expression of the class II antigen but caused no significant depletion of interstitial cells

Transport, atom blockade, and output coupling in a Tonks-Girardeau gas

International Nuclear Information System (INIS)

Rutherford, L.; McCann, J. F.; Goold, J.; Busch, Th.

2011-01-01

Recent experiments have demonstrated how quantum-mechanical impurities can be created within strongly correlated quantum gases and used to probe the coherence properties of these systems [S. Palzer, C. Zipkes, C. Sias, and M. Koehl, Phys. Rev. Lett. 103, 150601 (2009).]. Here we present a phenomenological model to simulate such an output coupler for a Tonks-Girardeau gas that shows qualitative agreement with the experimental results for atom transport and output coupling. Our model allows us to explore nonequilibrium transport phenomena in ultracold quantum gases and leads us to predict a regime of atom blockade, where the impurity component becomes localized in the parent cloud despite the presence of gravity. We show that this provides a stable mixed-species quantum gas in the strongly correlated limit.

An ENDOR spectrum of H atoms in solid H{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Kumada, Takayuki; Kumagai, J.; Aratono, Yasuyuki; Miyazaki, T. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kitagawa, N.; Noda, T.

1998-10-01

An ENDOR spectrum of H atoms produced in the {gamma}-rays irradiated solid H{sub 2} was measured at 4.2 K in order to elucidate the structures of the local environment of the H atoms in solid H{sub 2}. We found that the H atoms were not trapped in interstitial sites but in substitutional sites of the solid, and almost all ortho-H{sub 2} molecules at the first nearest sites from the H atoms converted into para-H{sub 2} molecules. This result shows that the ortho-para conversion is induced by electron spins of the H atoms. (author)

Unraveling atomic-level self-organization at the plasma-material interface

Science.gov (United States)

Allain, J. P.; Shetty, A.

2017-07-01

The intrinsic dynamic interactions at the plasma-material interface and critical role of irradiation-driven mechanisms at the atomic scale during exposure to energetic particles require a priori the use of in situ surface characterization techniques. Characterization of ‘active’ surfaces during modification at atomic-scale levels is becoming more important as advances in processing modalities are limited by an understanding of the behavior of these surfaces under realistic environmental conditions. Self-organization from exposure to non-equilibrium and thermalized plasmas enable dramatic control of surface morphology, topography, composition, chemistry and structure yielding the ability to tune material properties with an unprecedented level of control. Deciphering self-organization mechanisms of nanoscale morphology (e.g. nanodots, ripples) and composition on a variety of materials including: compound semiconductors, semiconductors, ceramics, polymers and polycrystalline metals via low-energy ion-beam assisted plasma irradiation are critical to manipulate functionality in nanostructured systems. By operating at ultra-low energies near the damage threshold, irradiation-driven defect engineering can be optimized and surface-driven mechanisms controlled. Tunability of optical, electronic, magnetic and bioactive properties is realized by reaching metastable phases controlled by atomic-scale irradiation-driven mechanisms elucidated by novel in situ diagnosis coupled to atomistic-level computational tools. Emphasis will be made on tailored surface modification from plasma-enhanced environments on particle-surface interactions and their subsequent modification of hard and soft matter interfaces. In this review, we examine current trends towards in situ and in operando surface and sub-surface characterization to unravel atomic-scale mechanisms at the plasma-material interface. This work will emphasize on recent advances in the field of plasma and ion

Engineering self-organising helium bubble lattices in tungsten.

Science.gov (United States)

Harrison, R W; Greaves, G; Hinks, J A; Donnelly, S E

2017-08-10

The self-organisation of void and gas bubbles in solids into superlattices is an intriguing nanoscale phenomenon. Despite the discovery of these lattices 45 years ago, the atomistics behind the ordering mechanisms responsible for the formation of these nanostructures are yet to be fully elucidated. Here we report on the direct observation via transmission electron microscopy of the formation of bubble lattices under He ion bombardment. By careful control of the irradiation conditions, it has been possible to engineer the bubble size and spacing of the superlattice leading to important conclusions about the significance of vacancy supply in determining the physical characteristics of the system. Furthermore, no bubble lattice alignment was observed in the directions pointing to a key driving mechanism for the formation of these ordered nanostructures being the two-dimensional diffusion of self-interstitial atoms.

The vacancy-interstitial model of DX centers

International Nuclear Information System (INIS)

Morgan, T.N.

1989-01-01

Recent DLTS (deep level transient spectroscopy) studies of 'DX' centers in dilute Al x Ga 1-x As alloys agree with a model of the deep neutral state in which the donor has moved into an adjacent interstitial site leaving behind a vacancy. The enthalpy and entropy of these states, which depend on the number (0 to 3) of Al atoms adjacent to the donors, have been obtained by fitting the data. This model, which also predicts the large potential barriers between the centered and relaxed states, thus accounting for PPC (persistent photoconductivity), is an extension to large displacement of the displaced donor model proposed earlier. It is equivalent to recent model of the EL2 metastable state based on displaced antisite double-donors. (author) 9 refs., 3 figs., 1 tab

Balance point characterization of interstitial fluid volume regulation.

Science.gov (United States)

Dongaonkar, R M; Laine, G A; Stewart, R H; Quick, C M

2009-07-01

The individual processes involved in interstitial fluid volume and protein regulation (microvascular filtration, lymphatic return, and interstitial storage) are relatively simple, yet their interaction is exceedingly complex. There is a notable lack of a first-order, algebraic formula that relates interstitial fluid pressure and protein to critical parameters commonly used to characterize the movement of interstitial fluid and protein. Therefore, the purpose of the present study is to develop a simple, transparent, and general algebraic approach that predicts interstitial fluid pressure (P(i)) and protein concentrations (C(i)) that takes into consideration all three processes. Eight standard equations characterizing fluid and protein flux were solved simultaneously to yield algebraic equations for P(i) and C(i) as functions of parameters characterizing microvascular, interstitial, and lymphatic function. Equilibrium values of P(i) and C(i) arise as balance points from the graphical intersection of transmicrovascular and lymph flows (analogous to Guyton's classical cardiac output-venous return curves). This approach goes beyond describing interstitial fluid balance in terms of conservation of mass by introducing the concept of inflow and outflow resistances. Algebraic solutions demonstrate that P(i) and C(i) result from a ratio of the microvascular filtration coefficient (1/inflow resistance) and effective lymphatic resistance (outflow resistance), and P(i) is unaffected by interstitial compliance. These simple algebraic solutions predict P(i) and C(i) that are consistent with reported measurements. The present work therefore presents a simple, transparent, and general balance point characterization of interstitial fluid balance resulting from the interaction of microvascular, interstitial, and lymphatic function.

Interstitial cystitis

Science.gov (United States)

... symptoms get better. Reduce or stop consuming caffeine, chocolate, carbonated beverages, citrus drinks, and foods with a ... rarely done anymore Support Groups Some people may benefit from taking part in interstitial cystitis support groups . ...

Interstitial Cystitis

Science.gov (United States)

... relieve symptoms. Diet. Alcohol, tomatoes, spices, carbonated drinks, chocolate, caffeine, citrus fruits and drinks, pickled foods, artificial ... at scheduled times and using relaxation techniques. Physical therapy. People who have interstitial cystitis may have painful ...

Stick–slip behavior identified in helium cluster growth in the subsurface of tungsten: effects of cluster depth

International Nuclear Information System (INIS)

Wang, Jinlong; Niu, Liang-Liang; Shu, Xiaolin; Zhang, Ying

2015-01-01

We have performed a molecular dynamics study on the growth of helium (He) clusters in the subsurface of tungsten (W) (1 0 0) at 300 K, focusing on the role of cluster depth. Irregular ‘stick–slip’ behavior exhibited during the evolution of the He cluster growth is identified, which is due to the combined effects of the continuous cluster growth and the loop punching induced pressure relief. We demonstrate that the He cluster grows via trap-mutation and loop punching mechanisms. Initially, the self-interstitial atom SIA clusters are almost always attached to the He cluster; while they are instantly emitted to the surface once a critical cluster pressure is reached. The repetition of this process results in the He cluster approaching the surface via a ‘stop-and-go’ manner and the formation of surface adatom islands (surface roughening), ultimately leading to cluster bursting and He escape. We reveal that, for the Nth loop punching event, the critical size of the He cluster to trigger loop punching and the size of the emitted SIA clusters are correspondingly increased with the increasing initial cluster depth. We tentatively attribute the observed depth effects to the lower formation energies of Frenkel pairs and the greatly reduced barriers for loop punching in the stress field of the W subsurface. In addition, some intriguing features emerge, such as the morphological transformation of the He cluster from ‘platelet-like’ to spherical, to ellipsoidal with a ‘bullet-like’ tip, and finally to a ‘bottle-like’ shape after cluster rupture. (paper)

Interstitial cystitis: painful bladder syndrome

Directory of Open Access Journals (Sweden)

R F Sholan

2018-02-01

Full Text Available Interstitial cystitis, or painful bladder syndrome, is a chronic inflammatory disease of a bladder of unknown etiology. It negatively affects the quality of life, causes depressive disorders, anxiety, and sexual dysfunction. Despite numerous studies, the etiology of interstitial cystitis is still unclear and it’s considered as painful bladder syndrome with multifactorial origin. According to the US National Health and Nutrition Examination Survey, 470/100 000 people (60/100 000 men, 850/100 000 women are diagnosed with interstitial cystitis. Diagnosis of the disease is difficult and is substantially based on clinical symptoms. Pelvic pain, urinary urgency, frequency and nocturia are the basic complaints in this pathology. The diagnosis requires exclusion of diseases with similar manifestations. So interstitial cystitis is frequently misdiagnosed as urinary tract infection, overactive bladder, urethral obstruction or diverticulosis, chronic prostatitis, bladder cancer, vulvodynia, endometriosis, and chronic pelvic pain. Etiopathogenesis of the disease is uncertain, which makes etiologic treatment impossible. Currently scientific discussions on the causes of disease continue as well as different treatment regimens are offered, but are often ineffective, palliative and temporary. The treatment for intersticial cystitis should focus on restoring normal bladder function, prevention of relapse of symptoms and improvement of patients’ quality of life. The literature review presents current view on the terminology, epidemiology, diagnosis and treatment of interstitial cystitis.

SIA

International Nuclear Information System (INIS)

Carniel, B.; Stefanini, A.; DeGrandi, G.

1987-01-01

In this paper the authors describe the design of a knowledge-based supporting system for Non Destructive Analysis of Plutonium isotopic composition, which fits into an integrated data evaluation scheme for safeguards. This system is intended to be an intelligent assistant to the inspection procedure, able to generate as much as possible correct measurements, to guide the inspector throughout the procedure and to report descriptive data to the data evaluation system. The problem of improving the measurement quality is tackled using expert system approach, which should convey into this tool some of the physicist knowledge. The system has been designed at CISE laboratories, in the frame of the cooperation among the JRC of Ispra, the International Atomic Energy Agency (IAEA) and the Safegards Directorate (DCS) of Luxemborg for the fissile material control and management program

A self-consistent mean field theory for diffusion in alloys

International Nuclear Information System (INIS)

Nastar, M.; Barbe, V.

2007-01-01

Starting from a microscopic model of the atomic transport via vacancies and interstitials in alloys, a self-consistent mean field (SCMF) kinetic theory yields the phenomenological coefficients L ij . In this theory, kinetic correlations are accounted for through a set of effective interactions within a non-equilibrium distribution function of the system. The introduction of a master equation describing the evolution with time of the distribution function and its moments leads to general self-consistent kinetic equations. The L ij of a face centered cubic alloy are calculated using the kinetic equations of Nastar (M. Nastar, Philos. Mag., 2005, 85, 3767, ref. 1) derived from a microscopic broken bond model of the vacancy jump frequency. A first approximation leads to an analytical expression of the L ij and a second approximation to a better agreement with the Monte Carlo simulations. A change of sign of the L ij is studied as a function of the microscopic parameters of the jump frequency. The L ij of a cubic centered alloy obtained for the complex diffusion mechanism of the dumbbell configuration of the interstitial are used to study the effect of an on-site rotation of the dumbbell on the transport. (authors)

Interstitial shadow on chest CT is associated with the onset of interstitial lung disease caused by chemotherapeutic drugs

International Nuclear Information System (INIS)

Niho, Seiji; Goto, Koichi; Yoh, Kiyotaka; Kim, Y.H.; Ohmatsu, Hironobu; Kubota, Kaoru; Saijo, Nagahiro; Nishiwaki, Yutaka

2006-01-01

Pretreatment computerized tomography (CT) films of the chest was studied to clarify the influence of interstitial shadow on developing interstitial lung disease (ILD). Eligible patients were those lung cancer patients who started to receive first-line chemotherapy between October 2001 and March 2004. Patients who received thoracic radiotherapy to the primary lesion, mediastinum, spinal or rib metastases were excluded. We reviewed pretreatment conventional CT and plain X-ray films of the chest. Ground-glass opacity, consolidation or reticular shadow without segmental distribution was defined as interstitial shadow, with this event being graded as mild, moderate or severe. If interstitial shadow was detected on CT films of the chest, but not via plain chest X-ray, it was graded as mild. Patients developing ILD were identified from medial records. A total of 502 patients were eligible. Mild, moderate and severe interstitial shadow was identified in 7, 8 and 5% of patients, respectively. A total of 188 patients (37%) received tyrosine kinase inhibitor (TKI) treatment, namely gefitinib or erlotinib. Twenty-six patients (5.2%) developed ILD either during or after chemotherapy. Multivariate analyses revealed that interstitial shadow on CT films of the chest and treatment history with TKI were associated with the onset of ILD. It is recommended that patients with interstitial shadow on chest CT are excluded from future clinical trials until this issue is further clarified, as it is anticipated that use of chemotherapeutic agents frequently mediate onset of ILD in this context. (author)

Continuous-measurement-enhanced self-trapping of degenerate ultracold atoms in a double well: Nonlinear quantum Zeno effect

International Nuclear Information System (INIS)

Li Weidong; Liu Jie

2006-01-01

In the present paper we investigate the influence of measurements on the quantum dynamics of degenerate Bose atoms gases in a symmetric double well. We show that continuous measurements enhance asymmetry on the density distribution of the atoms and broaden the parameter regime for self-trapping. We term this phenomenon as nonlinear quantum Zeno effect in analog to the celebrated Zeno effect in a linear quantum system. Under discontinuous measurements, the self-trapping due to the atomic interaction in the degenerate bosons is shown to be destroyed completely. Underlying physics is revealed and possible experimental realization is discussed

Dechanneling measurements of defect depth profiles and effective cross-channel distribution of misaligned atoms in ion irradiated gold

International Nuclear Information System (INIS)

Pronko, P.P.

1975-01-01

Defect depth profiles for self ion and He + irradiated gold are obtained from single and multiple scatter dechanneling analysis in single crystal gold films. Quantitative defect densities are obtained through use of atomic scattering cross sections. Integral damage profiles are extracted from the dechanneling spectra and subsequently differentiated to yield the volume concentration of defects as a function of depth. Results from the self ion irradiations suggest that incident ions produce defect distributions across depths much greater than predicted by random stopping theory. This is in agreement with TEM observations of others. Comparison of the experimental profiles is made with theoretical vacancy distributions predicted by defect diffusion in a radiation environment. Similarities are observed for the low fluence irradiations suggesting that profile characteristics may be controlled by rapid migration and loss of interstitials to the film surfaces during irradiation. Information on the across-channel distribution of misaligned atoms in the damaged films is obtained with the steady increase of transverse energy model applied to the dechanneling spectra. A predominance of slight misalignment is observed with no contribution to dechanneling coming from atoms displaced significantly close to the center of the channels. This is in keeping with what is expected for crystal distortions caused by the strain fields associated with vacancy cluster defects

Dechanneling measurements of defect depth profiles and effective cross-channel distribution of misaligned atoms in ion-irradiated gold

International Nuclear Information System (INIS)

Pronko, P.P.

1976-01-01

Defect depth profiles for self-ion and He + irradiated gold are obtained from single and multiple scatter dechanneling analysis in single-crystal gold films. Quantitative defect densities are obtained through use of atomic-scattering cross sections. Integral damage profiles are extracted from the dechanneling spectra and subsequently differentiated to yield the volume concentration of defects as a function of depth. Results from the self-ion irradiations suggest that incident ions produce defect distributions across depths much greater than predicted by random stopping theory. This is in agreement with TEM observations of others. Comparison of the experimental profiles is made with theoretical vacancy distributions predicted by defect diffusion in a radiation environment. Similarities are observed for the low-fluence irradiations, suggesting that profile characteristics may be controlled by rapid migration and loss of interstitials to the film surfaces during irradiation. Information on the across-channel distribution of misaligned atoms in the damaged films is obtained with the steady increase of transverse energy model. A predominance of slight misalignment is observed with no contribution to dechanneling coming from atoms displaced significantly close to the center of the channels. This is in keeping with what is expected for crystal distortions caused by the strain fields associated with vacancy cluster defects. (Auth.)

Characterization of SiaA, a streptococcal heme-binding protein associated with a heme ABC transport system.

Science.gov (United States)

Sook, Brian R; Block, Darci R; Sumithran, Suganya; Montañez, Griselle E; Rodgers, Kenton R; Dawson, John H; Eichenbaum, Zehava; Dixon, Dabney W

2008-02-26

Many pathogenic bacteria require heme and obtain it from their environment. Heme transverses the cytoplasmic membrane via an ATP binding cassette (ABC) pathway. Although a number of heme ABC transport systems have been described in pathogenic bacteria, there is as yet little biophysical characterization of the proteins in these systems. The sia (hts) gene cluster encodes a heme ABC transporter in the Gram positive Streptococcus pyogenes. The lipoprotein-anchored heme binding protein (HBP) of this transporter is SiaA (HtsA). In the current study, resonance Raman (rR), magnetic circular dichroism (MCD), and nuclear magnetic resonance (NMR) spectroscopies were used to determine the coordination state and spin state of both the ferric and ferrous forms of this protein. Identifiers from these techniques suggest that the heme is six-coordinate and low-spin in both oxidation states of the protein, with methionine and histidine as axial ligands. SiaA has a pKa of 9.7 +/- 0.1, attributed to deprotonation of the axial histidine. Guanidinium titration studies show that the ferric state is less stable than the ferrous state, with DeltaG(H2O) values for the oxidized and reduced proteins of 7.3 +/- 0.8 and 16.0 +/- 3.6 kcal mol-1, respectively. The reductive and oxidative midpoint potentials determined via spectroelectrochemistry are 83 +/- 3 and 64 +/- 3 mV, respectively; the irreversibility of heme reduction suggests that redox cycling of the heme is coupled to a kinetically sluggish change in structure or conformation. The biophysical characterization described herein will significantly advance our understanding of structure-function relationships in HBP.

Investigation of point defects diffusion in bcc uranium and U–Mo alloys

International Nuclear Information System (INIS)

Smirnova, D.E.; Kuksin, A.Yu.; Starikov, S.V.

2015-01-01

We present results of investigation of point defects formation and diffusion in pure γ-U and γ-U–Mo fuel alloys. The study was performed using molecular dynamics simulation with the different interatomic potentials. The point defects formation and migration energies were estimated for bcc γ-U and U–9 wt.%Mo alloy. The calculated diffusivities of atoms via defects are provided for pure γ-U and for the alloy components. Analysis of simulation results shows that self-interstitial atoms play a leading role in the self-diffusion processes in the materials studied. This fact can explain a remarkably high self-diffusion mobility observed experimentally for γ-U. The self-diffusion coefficients in γ-U calculated in this assumption agree with the data measured experimentally. It is shown that alloying of γ-U with Mo increase formation energy for self-interstitial atoms and decelerate their mobility. These changes lead to decrease of self-diffusion coefficients in U–Mo alloy compared to pure U

Percepção de enfermeiros intensivistas sobre distanásia em unidade de terapia intensiva Intensivist nurses perception of intensive care unit dysthanasia

Directory of Open Access Journals (Sweden)

Fernando Salomão da Silva

2009-06-01

Full Text Available OBJETIVO: Identificar e analisar a percepção de enfermeiros da unidade de terapia intensiva de um hospital escola em Londrina sobre distanásia em pacientes terminais na unidade de terapia intensiva. MÉTODOS: Estudo de natureza qualitativa. Os dados foram coletados por meio de entrevista semi-estruturada gravada, com nove enfermeiros das unidades de terapia intensiva de um hospital escola, no mês de janeiro de 2009. Foi utilizada a análise temática para analisar os discursos dos sujeitos e identificar as categorias de discussão. RESULTADOS: Foram identificadas cinco categorias que foram discutidas com base na experiência dos autores e na literatura, sendo elas: medidas que prolongam a vida do paciente fora de possibilidade de cura na unidade de terapia intensiva; ações/reações dos enfermeiros diante da distanásia; motivos que levam ao prolongamento da vida de pacientes fora de possibilidade de cura; sentimentos dos enfermeiros sobre a distanásia e prolongamento da vida; medidas de cuidado em oposição à distanásia. CONCLUSÃO: A vivência dos enfermeiros perante as ações de distanásia mostrou-se complexa, sendo um fator de sofrimento, frustração a inquietação para estes profissionais. A falta de comunicação destaca-se como fator importante na visão dos enfermeiros para a ocorrência de distanásia e a medida para substituir a distanásia são os cuidados que proporcionam alivio do sofrimento.PURPOSE: Identify and evaluate the perception of Intensivist Nurses in a University Hospital in Londrina, of dysthanasia in terminal patients at the Intensive Care Unit. METHODS: Qualitative study. Data were collected by semi-structured recorded interview involving nine nurses working in a university hospital intensive care units, during January 2009. A thematic analysis was used to evaluate subjects' speech and identify discussion categories. RESULTS: Five categories were identified, discussed based on the authors' experience and

Ab initio molecular dynamics simulation of interstitial diffusion in Ni–Cr alloys and implications for radiation induced segregation

Energy Technology Data Exchange (ETDEWEB)

Barnard, L., E-mail: lmbarnard@wisc.edu; Morgan, D., E-mail: ddmorgan@wisc.edu

2014-06-01

In this study, ab initio molecular dynamics, implemented via density functional theory, is used to simulate self-interstitial diffusion in pure Ni and in the Ni-18 at.% Cr model alloy. Interstitial tracer diffusivities are measured from simulation results for pure Ni and for both Ni and Cr in the Ni–18Cr alloy. An Arrhenius function fit to these tracer diffusivities is then used in a rate theory model for radiation induced segregation, along with the experimentally measured vacancy diffusivities. It is predicted that interstitial diffusion has a tendency to cause Cr enrichment near grain boundaries, partially counterbalancing the tendency for vacancy diffusion to cause Cr depletion. This results in more mild Cr depletion than would result if only the vacancy diffusion were accounted for, in better agreement with experiment. This physical description of RIS in Ni–Cr alloys, which invokes the effects of both vacancy and interstitial diffusion, is distinct from the conventional description which accounts only for the effect of vacancy diffusion.

Ab initio molecular dynamics simulation of interstitial diffusion in Ni–Cr alloys and implications for radiation induced segregation

International Nuclear Information System (INIS)

Barnard, L.; Morgan, D.

2014-01-01

In this study, ab initio molecular dynamics, implemented via density functional theory, is used to simulate self-interstitial diffusion in pure Ni and in the Ni-18 at.% Cr model alloy. Interstitial tracer diffusivities are measured from simulation results for pure Ni and for both Ni and Cr in the Ni–18Cr alloy. An Arrhenius function fit to these tracer diffusivities is then used in a rate theory model for radiation induced segregation, along with the experimentally measured vacancy diffusivities. It is predicted that interstitial diffusion has a tendency to cause Cr enrichment near grain boundaries, partially counterbalancing the tendency for vacancy diffusion to cause Cr depletion. This results in more mild Cr depletion than would result if only the vacancy diffusion were accounted for, in better agreement with experiment. This physical description of RIS in Ni–Cr alloys, which invokes the effects of both vacancy and interstitial diffusion, is distinct from the conventional description which accounts only for the effect of vacancy diffusion

Gallium interstitial contributions to diffusion in gallium arsenide

Science.gov (United States)

Schick, Joseph T.; Morgan, Caroline G.

2011-09-01

A new diffusion path is identified for gallium interstitials, which involves lower barriers than the barriers for previously identified diffusion paths [K. Levasseur-Smith and N. Mousseau, J. Appl. Phys. 103, 113502 (2008), P. A. Schultz and O. A. von Lilienfeld, Modelling and Simulation in Materials Science and Engineering 17, 084007 (2009)] for the charge states which dominate diffusion over most of the available range of Fermi energies. This path passes through the ⟨110⟩ gallium-gallium split interstitial configuration, and has a particularly low diffusion barrier of 0.35 eV for diffusion in the neutral charge state. As a part of this work, the character of the charge states for the gallium interstitials which are most important for diffusion is investigated, and it is shown that the last electron bound to the neutral interstitial occupies a shallow hydrogenic bound state composed of conduction band states for the hexagonal interstitial and both tetrahedral interstitials. How to properly account for the contributions of such interstitials is discussed for density-functional calculations with a k-point mesh not including the conduction band edge point. Diffusion barriers for gallium interstitials are calculated in all the charge states which can be important for a Fermi level anywhere in the gap, q = 0, +1, +2, and +3, for diffusion via the ⟨110⟩ gallium-gallium split interstitial configuration and via the hexagonal interstitial configuration. The lowest activation enthalpies over most of the available range of Fermi energies are found to correspond to diffusion in the neutral or singly positive state via the ⟨110⟩ gallium-gallium split interstitial configuration. It is shown that several different charge states and diffusion paths contribute significantly for Fermi levels within 0.2 eV above the valence band edge, which may help to explain some of the difficulties [H. Bracht and S. Brotzmann, Phys. Rev. B 71, 115216 (2005)] which have been

Effect of solute atoms on collision cascades in copper and molybdenum irradiated with self-ions

International Nuclear Information System (INIS)

English, C.A.; Eyre, B.L.; Wadley, H.; Stathopoulos, A.Y.

1975-01-01

An examination of the effect material purity has on the numbers and sizes of the vacancy loops formed in collision cascades produced by self-ion irradiation of copper and molybdenum is reported. It is shown that substitutional and interstitial impurities both markedly reduce the damage generated in molybdenum by 60 keV Mo + ions but little effect is seen in copper irradiated by 30 keV Cu + ions. These results are compared with recent observations of vacancy defects in type 316 stainless steel following irradiation with 40-200 keV Cr + . The comparison highlights the much lower vacancy concentration retained in visible clusters in the complex alloy

Computer simulation of strain-induced ordering in interstitial solutions based on the b.c.c. Ta lattice

International Nuclear Information System (INIS)

Blanter, M.S.; Khachaturyan, A.G.

1980-01-01

A computer simulation is made of strain-induced ordering of interstitial atoms within octahedral interstices in the Ta host lattice. The calculation technique allows to take into account infinite-range strain-induced interaction. Computer simulation of ordering process enables to model the sequence of structure changes which occur during the ordering process and to find the equilibrium structure of the stable interstitial superstructures. The structures of high-temperature ordering phases obtained by the method of static concentration waves coincide with those obtained by means of computer simulation. However computer simulation enables to predict the structures of low-temperature ordered phases which cannot be obtained by the method of concentration waves. Comparison of computer simulation results and structures of observed ordered phases demonstrates good agreement. (author)

Effect of thermal friction on the generation and transport of interstitial defects in irradiated metals

CERN Document Server

Dudarev, S L

2002-01-01

Generation of interstitial and vacancy defects under 14.1 MeV neutron irradiation is expected to drive the evolution of microstructure of materials in a future fusion power station. We investigate effects of thermal friction associated with the interaction between mobile clusters of interstitial atoms produced in collision cascades and phonon excitations. Phonons give rise to the random Brownian motion of clusters in the crystal lattice. Phonon excitations are also responsible for the dissipation of energy of rapidly moving clusters formed at the periphery of collision cascades. We investigate how the coefficient of thermal friction depends on the structure of clusters. We also discuss implications of our findings for understanding the origin of higher resistance of bcc metals to irradiation and the connection between this phenomenon and the long-range effect observed in experiments on ion implantation.

Energy variable monoenergetic positron beam study of oxygen atoms in Czochralski grown Si

International Nuclear Information System (INIS)

Tanigawa, S.; Wei, L.; Tabuki, Y.; Nagai, R.; Takeda, E.

1992-01-01

A monoenergetic positron beam has been used to investigate the state of interstitial oxygen in Czochralski-grown Si with the coverage of SiO 2 (100 nm) and poly-Si (200 nm)/SiO 2 (100 nm), respectively. It was found that (i) the growth of SiO 2 gives rise to a strong Doppler broadening of positron annihilation radiations in the bulk of Si, (ii) such a broadening can be recovered to the original level by annealing at 450degC, by the removal of overlayers using chemical etching and long-term aging at room temperature, (iii) the film stress over the CZ-grown Si is responsible for the rearrangement of oxygen atoms in S and (iv) only tensile stress gives rise to the clustering of oxygen atoms. The observed broadening was assigned to arise from the positron trapping by oxygen interstitial clusters. It was concluded that film stress is responsible for the rearrangement of oxygen atoms in CZ-grown Si. (author)

Regulation of tumor invasion by interstitial fluid flow

International Nuclear Information System (INIS)

Shieh, Adrian C; Swartz, Melody A

2011-01-01

The importance of the tumor microenvironment in cancer progression is undisputed, yet the significance of biophysical forces in the microenvironment remains poorly understood. Interstitial fluid flow is a nearly ubiquitous and physiologically relevant biophysical force that is elevated in tumors because of tumor-associated angiogenesis and lymphangiogenesis, as well as changes in the tumor stroma. Not only does it apply physical forces to cells directly, but interstitial flow also creates gradients of soluble signals in the tumor microenvironment, thus influencing cell behavior and modulating cell–cell interactions. In this paper, we highlight our current understanding of interstitial fluid flow in the context of the tumor, focusing on the physical changes that lead to elevated interstitial flow, how cells sense flow and how they respond to changes in interstitial flow. In particular, we emphasize that interstitial flow can directly promote tumor cell invasion through a mechanism known as autologous chemotaxis, and indirectly support tumor invasion via both biophysical and biochemical cues generated by stromal cells. Thus, interstitial fluid flow demonstrates how important biophysical factors are in cancer, both by modulating cell behavior and coupling biophysical and biochemical signals

Factor solutions of the Social Phobia Scale (SPS) and the Social Interaction Anxiety Scale (SIAS) in a Swedish population.

Science.gov (United States)

Mörtberg, Ewa; Reuterskiöld, Lena; Tillfors, Maria; Furmark, Tomas; Öst, Lars-Göran

2017-06-01

Culturally validated rating scales for social anxiety disorder (SAD) are of significant importance when screening for the disorder, as well as for evaluating treatment efficacy. This study examined construct validity and additional psychometric properties of two commonly used scales, the Social Phobia Scale and the Social Interaction Anxiety Scale, in a clinical SAD population (n = 180) and in a normal population (n = 614) in Sweden. Confirmatory factor analyses of previously reported factor solutions were tested but did not reveal acceptable fit. Exploratory factor analyses (EFA) of the joint structure of the scales in the total population yielded a two-factor model (performance anxiety and social interaction anxiety), whereas EFA in the clinical sample revealed a three-factor solution, a social interaction anxiety factor and two performance anxiety factors. The SPS and SIAS showed good to excellent internal consistency, and discriminated well between patients with SAD and a normal population sample. Both scales showed good convergent validity with an established measure of SAD, whereas the discriminant validity of symptoms of social anxiety and depression could not be confirmed. The optimal cut-off score for SPS and SIAS were 18 and 22 points, respectively. It is concluded that the factor structure and the additional psychometric properties of SPS and SIAS support the use of the scales for assessment in a Swedish population.

Exploring depression, self-esteem and verbal fluency with different degrees of internet addiction among Chinese college students.

Science.gov (United States)

Nie, Jia; Zhang, Wei; Liu, Ying

2017-01-01

The aims of this study were to explore depression, self-esteem and verbal fluency functions among normal internet users, mild internet addictions and severe internet addictions. The survey sample consisted of 316 college students, and their internet addiction symptoms, depression and self-esteem symptoms were assessed using the Revised Chen Internet Addiction Scale (CIAS-R), Zung Self-Rating Depression Scale (ZSDS), Rosenberg Self-Esteem Scale (RSES), respectively. From this sample, 16 students with non-addictions, 19 students with mild internet addiction (sub-MIA) and 15 students with severe internet addiction (sub-SIA) were recruited and subjected to the classical verbal fluency tests, including the semantic and phonemic fluency task. The results indicated that severe internet addiction in the survey sample showed the highest tendency towards depressive symptoms and lowest self-esteem scores, and sub-SIA showed poor performance on the semantic fluency task. In conclusion, severe internet addiction was significantly associated with depression, low self-esteem and semantic verbal fluency problems. Copyright © 2017 Elsevier Inc. All rights reserved.

Numerical atomic scale simulations of the microstructural evolution of ferritic alloys under irradiation

International Nuclear Information System (INIS)

Vincent, E.

2006-12-01

In this work, we have developed a model of point defect (vacancies and interstitials) diffusion whose aim is to simulate by kinetic Monte Carlo (KMC) the formation of solute rich clusters observed experimentally in irradiated FeCuNiMnSi model alloys and in pressure vessel steels. Electronic structure calculations have been used to characterize the interactions between point defects and the different solute atoms. Each of these solute atoms establishes an attractive bond with the vacancy. As for Mn, which is the element which has the weakest bond with the vacancy, it establishes more favourable bonds with interstitials. Binding energies, migration energies as well as other atomic scale properties, determined by ab initio calculations, have led to a parameter set for the KMC code. Firstly, these parameters have been optimised on thermal ageing experiments realised on the FeCu binary alloy and on complex alloys, described in the literature. The vacancy diffusion thermal annealing simulations show that when a vacancy is available, all the solutes migrate and form clusters, in agreement with the observed experimental tendencies. Secondly, to simulate the microstructural evolution under irradiation, we have introduced interstitials in the KMC code. Their presence leads to a more efficient transport of Mn. The first simulations of electron and neutron irradiations show that the model results are globally qualitatively coherent with the experimentally observed tendencies. (author)

A eutanásia na visão do garantismo penal

OpenAIRE

Reicher, Regina Maria

2005-01-01

Num cotejo entre a eutanásia e o garantismo de Luigi Ferrajoli, quanto à proibição penal, os princípios da lesividade e necessidade, e o direito penal mínimo, este estudo faz uma projeção sobre as principais conseqüências desse comportamento em matéria penal, notadamente quanto à sua repercussão sobre o princípio da dignidade da pessoa humana, que é corolário lógico do Estado Democrático de Direito. Não se justifica, no modelo de direito penal mínimo propugnado pelo garantismo, a penalizaç...

First-principles study of Frenkel pair recombination in tungsten

International Nuclear Information System (INIS)

Qin, Shi-Yao; Jin, Shuo; Li, Yu-Hao; Zhou, Hong-Bo; Zhang, Ying; Lu, Guang-Hong

2017-01-01

The recombination of one Frenkel pair in tungsten has been investigated through first-principles simulation. Two different recombination types have been identified: instantaneous and thermally activated. The small recombination barriers for thermally activated recombination cases indicate that recombination can occur easily with a slightly increased temperature. For both of the two recombination types, recombination occurs through the self-interstitial atom moving towards the vacancy. The recombination process can be direct or through replacement sequences, depending on the vertical distance between the vacancy and the 〈1 1 1〉 line of self-interstitial atom pair.

HES and T'Sou-ke Nation awarded CanSIA solar project of the year

Energy Technology Data Exchange (ETDEWEB)

Anon.

2010-01-15

Home Energy Solutions (HES) has installed the largest solar photovoltaic solar array in British Columbia. In 2009, the Sum-SHA-Thut installation won the award for the Solar Project of the Year by the Canadian Solar Industries Association (CanSIA). It was built for Vancouver Island's T'Sou-ke Nation and its success shows great promise for solar electric generation in Canada. Energy consumption has decreased 30 per cent since the installation in July 2009, making the T'Sou-ke First Nation the most solar-intensive nation per capita in the world. The solar community project demonstrates that as a clean, renewable source of energy, solar electricity is a real solution for climate change, both internationally and at a local level. The timing of the CanSIA award is significant for the Canadian solar industry, falling in the midst of the Copenhagen Climate Change Conference and just shortly after Ontario introduced its micro feed-in-tariff program for renewable energy technologies. The project also demonstrates British Columbia's leadership in the alternative energy sector, and how solar can play a significant role in the future energy supply. 1 fig.

Interstitial hydraulic conductivity and interstitial fluid pressure for avascular or poorly vascularized tumors.

Science.gov (United States)

Liu, L J; Schlesinger, M

2015-09-07

A correct description of the hydraulic conductivity is essential for determining the actual tumor interstitial fluid pressure (TIFP) distribution. Traditionally, it has been assumed that the hydraulic conductivities both in a tumor and normal tissue are constant, and that a tumor has a much larger interstitial hydraulic conductivity than normal tissue. The abrupt transition of the hydraulic conductivity at the tumor surface leads to non-physical results (the hydraulic conductivity and the slope of the TIFP are not continuous at tumor surface). For the sake of simplicity and the need to represent reality, we focus our analysis on avascular or poorly vascularized tumors, which have a necrosis that is mostly in the center and vascularization that is mostly on the periphery. We suggest that there is an intermediary region between the tumor surface and normal tissue. Through this region, the interstitium (including the structure and composition of solid components and interstitial fluid) transitions from tumor to normal tissue. This process also causes the hydraulic conductivity to do the same. We introduce a continuous variation of the hydraulic conductivity, and show that the interstitial hydraulic conductivity in the intermediary region should be monotonically increasing up to the value of hydraulic conductivity in the normal tissue in order for the model to correspond to the actual TIFP distribution. The value of the hydraulic conductivity at the tumor surface should be the lowest in value. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electronic structure of light impurities in α-Fe and V

International Nuclear Information System (INIS)

Gong Xingao; Zeng Zhi; Zheng Wingqi

1987-07-01

The electronic structure of α-Fe and V with hydrogen and carbon as impurities is calculated using the embedded cluster models in the framework of self-consistent local density theory. The results obtained reveal that the charge transfer between the H atom and the host atom is small, but the magnetic moments of neighbouring Fe atoms are reduced. The total energy implies that hydrogen in α-Fe is more easily found to occupy the octahedral interstitial site. On the other hand, there is a charge transfer between the C atom and the host atoms. The distance between the carbon and the nearest neighbour iron atoms is 23% elongated. The interaction between the hydrogen and the carbon impurities was studied using a set of clusters of Fe 10 CH in which the atoms were located in five kinds of configuration. The energy of clusters with hydrogen on octahedral interstitial site is lower than that on the tetrahedral interstitial site. (author). 10 refs, 6 figs, 2 tabs

Modeling of long-range migration of boron interstitials

International Nuclear Information System (INIS)

Velichko, O.I.; Burunova, O.N.

2009-01-01

A model of the interstitial migration of ion-implanted dopant in silicon during low-temperature thermal treatment has been formulated. It is supposed that the boron interstitials are created during ion implantation or at the initial stage of annealing. During thermal treatment a migration of these impurity interstitials to the surface and in the bulk of a semiconductor occurs. On this basis, a simulation of boron redistribution during thermal annealing for 35 minutes at a temperature of 800 0 C has been carried out. The calculated boron profile agrees well with the experimental data. A number of the parameters describing the interstitial diffusion have been derived. In particular, the average migration length of nonequilibrium boron interstitials is equal to 0.092 μm at a temperature of 800 0 C. To carry out modeling of ion-implanted boron redistribution, the analytical solutions of nonstationary diffusion equation for impurity interstitials have been obtained. The case of Dirichlet boundary conditions and the case of reflecting boundary on the surface of a semiconductor have been considered. (authors)

Self-Regular Black Holes Quantized by means of an Analogue to Hydrogen Atoms

CERN Document Server

Liu, Chang; Wu, Yu-Mei; Zhang, Yu-Hao

2016-01-01

We suggest a proposal of quantization for black holes that is based on an analogy between a black hole and a hydrogen atom. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of non-extreme black holes are chosen to be the probability densities of excited states with no angular momenta. Consequently, it is logical to accept quantization of mean radii of hydrogen atoms as that of black hole horizons. In this way, quantization of total black hole masses is deduced. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.

Interstitial micelles in binary blends of A B A triblock copolymers and homopolymers

Science.gov (United States)

Wołoszczuk, S.; Banaszak, M.

2018-01-01

We investigate triblock-homopolymer blends of types A1BA2/A and A1BA2/B, using a lattice Monte Carlo method. While the simulated triblock chains are compositionally symmetric in terms of the A-to-B volume ratio, the A1 block is significantly shorter than the A2 block. For the pure A1BA2 melt and the A1BA2 solutions in selective solvent the phase behavior is relatively well known, including existence and stability of the interstitial micelles which were discovered in previous Monte Carlo simulations. In this paper we study the stability of the interstitial micelles as a function of triblock volume fraction in selective homopolymers of either type A or type B, using two significantly different homopolymer chain lengths. We found that adding selective homopolymer of type A shifts the stability of the interstitial micelles into significantly higher temperatures. We also obtained, via self-assembly, intriguing new nanostructures which can be identified as ordered truncated octahedra. Finally, we established that the phase behavior of the triblock-homopolymer blends depends relatively weakly on the chain length of the added homopolymer.

Irradiation-induced displacement of Ag atoms from lattice sites in an Al-0.2% Mg-0.1% Ag crystal

International Nuclear Information System (INIS)

Swanson, M.L.; Howe, L.M.; Quenneville, A.F.

1976-01-01

In irradiated alloys of Al containing approximately 0.1 at% Ag, the backscattering - channelling method shows that Al-Ag dumbells are created by the trapping of Al interstitial atoms at Ag solute atoms. The present results demonstrate that the addition of 0.2 at% Mg to such irradiated alloys retards not only the formation of Al-Ag dumbells during annealing from 30 to 100 K but also their annihilation during annealing from 180 to 240 K. Al interstitials are released from Mg traps at 100 to 160 K, causing further trapping at Ag atoms. Approximately 70% of the Ag atoms return to lattice sites at approximately 200 K (stage III) (compared with 100% in the Al-0.1% Ag alloys) and the remainder return to lattice sites at approximately 260 K. These results favour migration of Al-Ag dumbells rather than vacancies during stage III annealing. (author)

Idiopathic interstitial pneumonias: radiologic-pathologic correlation

International Nuclear Information System (INIS)

Yoon, Young Cheol; Suh, Gee Young; Han, Joung Ho; Lee, Kyung Soo

2002-01-01

Idiopathic interstitial pneumonias are at present classified as one of four types: usual, nonspecific, acute, or desquamative. The acute form has the worst prognosis, followed by the usual and the nonspecific form; it is in desquamative cases that prognosis is best. At high-resolution CT, usual interstitial pneumonia, the most frequent type, manifests as patchy subpleural areas of ground-glass attenuation, irregular linear opacity, and honeycombing, which the nonspecific type, the second most frequent, appears as subpleural patchy areas of ground-glass attenuation with associated areas of irregular linear opacity. Acute interstitial pneumonia demonstrates extensive bilateral airspace consolidation and patchy or diffuse bilateral areas of ground-glass attenuation in middle and lower lung zones

[Modern Views on Children's Interstitial Lung Disease].

Science.gov (United States)

Boĭtsova, E V; Beliashova, M A; Ovsiannikov, D Iu

2015-01-01

Interstitial lung diseases (ILD, diffuse lung diseases) are a heterogeneous group of diseases in which a pathological process primarily involved alveoli and perialveolar interstitium, resulting in impaired gas exchange, restrictive changes of lung ventilation function and diffuse interstitial changes detectable by X-ray. Children's interstitial lung diseases is an topical problem ofpediatricpulmonoogy. The article presents current information about classification, epidemiology, clinical presentation, diagnostics, treatment and prognosis of these rare diseases. The article describes the differences in the structure, pathogenesis, detection of various histological changes in children's ILD compared with adult patients with ILD. Authors cite an instance of registers pediatric patients with ILD. The clinical semiotics of ILD, the possible results of objective research, the frequency of symptoms, the features of medical history, the changes detected on chest X-rays, CT semiotics described in detail. Particular attention was paid to interstitial lung diseases, occurring mainly in newborns and children during the first two years of life, such as congenital deficiencies of surfactant proteins, neuroendocrine cell hyperplasia of infancy, pulmonary interstitial glycogenosis. The diagnostic program for children's ILD, therapy options are presented in this article.

Self-limiting atomic layer deposition of conformal nanostructured silver films

International Nuclear Information System (INIS)

Golrokhi, Zahra; Chalker, Sophia; Sutcliffe, Christopher J.; Potter, Richard J.

2016-01-01

Graphical abstract: - Highlights: • We grow metallic silver by direct liquid injection thermal atomic layer deposition. • Highly conformal silver nanoparticle coatings on high aspect ratio surfaces. • An ALD temperature growth window between 123 and 128 °C is established. • ALD cycles provides sub nanometre control of silver growth. • Catalytic dehydrogenation ALD mechanism has been elucidated by in-situ QCM. - Abstract: The controlled deposition of ultra-thin conformal silver nanoparticle films is of interest for applications including anti-microbial surfaces, plasmonics, catalysts and sensors. While numerous techniques can produce silver nanoparticles, few are able to produce highly conformal coatings on high aspect ratio surfaces, together with sub-nanometre control and scalability. Here we develop a self-limiting atomic layer deposition (ALD) process for the deposition of conformal metallic silver nanoparticle films. The films have been deposited using direct liquid injection ALD with ((hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene)) and propan-1-ol. An ALD temperature window between 123 and 128 °C is identified and within this range self-limiting growth is confirmed with a mass deposition rate of ∼17.5 ng/cm"2/cycle. The effects of temperature, precursor dose, co-reactant dose and cycle number on the deposition rate and on the properties of the films have been systematically investigated. Under self-limiting conditions, films are metallic silver with a nano-textured surface topography and nanoparticle size is dependent on the number of ALD cycles. The ALD reaction mechanisms have been elucidated using in-situ quartz crystal microbalance (QCM) measurements, showing chemisorption of the silver precursor, followed by heterogeneous catalytic dehydrogenation of the alcohol to form metallic silver and an aldehyde.

Smoking-related interstitial lung diseases: histopathological and imaging perspectives

Energy Technology Data Exchange (ETDEWEB)

Desai, S.R.; Ryan, S.M.; Colby, T.V

2003-04-01

The present review focuses on the interstitial lung diseases related to smoking. Thus, the pathology and radiology of Langerhans cell histiocytosis, desquamative interstitial pneumonia, respiratory bronchiolitis and respiratory bronchiolitis-associated-interstitial lung disease are considered. The more tenuous association between pulmonary fibrosis and smoking is also discussed.

Smoking-related interstitial lung diseases: histopathological and imaging perspectives

International Nuclear Information System (INIS)

Desai, S.R.; Ryan, S.M.; Colby, T.V.

2003-01-01

The present review focuses on the interstitial lung diseases related to smoking. Thus, the pathology and radiology of Langerhans cell histiocytosis, desquamative interstitial pneumonia, respiratory bronchiolitis and respiratory bronchiolitis-associated-interstitial lung disease are considered. The more tenuous association between pulmonary fibrosis and smoking is also discussed

Anomalous diffusion in niobium. Study of solute diffusion mechanism of iron in niobium

International Nuclear Information System (INIS)

Ablitzer, D.

1977-01-01

In order to explain anomalously high diffusion velocities observed for iron diffusion in niobium, the following parameters were measured: isotope effect, b factor (which expresses the effect of iron on niobium self-diffusion), self-diffusion coefficient of niobium, solute diffusion coefficient of iron in niobium. The results obtained show that neither pure vacancy models, nor diffusion in the lattice defects (dislocations, sub-boundaries, grain boundaries), nor pure interstitialy mechanisms, nor simple or cyclic exchange mechanisms agree with experiments. A mechanism is proposed which considers an equilibrium between substitution iron atoms and interstitial iron atoms. The diffusion of iron then occurs through interstitial vancancy pairs [fr

Interstitial Granulomatous Dermatitis (IGD

Directory of Open Access Journals (Sweden)

Tiberiu Tebeica

2017-07-01

Full Text Available We report the case of a 42 years old male patient suffering from skin changes , which appeared in the last 7-8 years.  Two biopsies were performed during the evolution of the lesion. Both showed similar findings that consisted in a busy dermis with interstitial, superficial and deep infiltrates of lymphocytes and histiocytes dispersed among collagen bundles, with variable numbers of neutrophils scattered throughout. Some histiocytes were clustered in poorly formed granuloma that included rare giant cells, with discrete Palisades and piecemeal collagen degeneration, but without mucin deposition or frank necrobiosis of collagen. The clinical and histologic findings were supportive for interstitial granulomatous dermatitis. Interstitial granulomatous dermatitis (IGD is a poorly understood entity that was regarded by many as belonging to the same spectrum of disease or even synonym with palisaded and neutrophilic granulomatous dermatitis (PNGD. Although IGD and PNGD were usually related to connective tissue disease, mostly rheumatoid arthritis, some patients with typical histologic findings of IGD never develop autoimmune disorders, but they have different underlying conditions, such as metabolic diseases, lymphoproliferative disorders or other malignant tumours. These observations indicate that IGD and PNGD are different disorders with similar manifestations.

Interaction of primary cascades with different atomic grain boundaries in α-Zr: An atomic scale study

Energy Technology Data Exchange (ETDEWEB)

Hatami, F.; Feghhi, S.A.H., E-mail: a.feghhi@gmail.com; Arjhangmehr, A., E-mail: ms.arjangmehr@gmail.com; Esfandiarpour, A.

2016-11-15

In this paper, we investigate interaction of primary cascades with grain boundaries (GBs) in α-Zr using the atomistic-scale simulations, and intend to study the influence of different GB structures on production and evolution of defects on picosecond timescale. We observe that, contrary to the previous results in cubic metals, GBs in α-Zr are not necessarily biased toward interstitials, and can preferentially absorb vacancies. Further, in terms of energetic and kinetic behavior, we find that GBs act as defect sinks due to the substantial reduction of defect formation energies and migration barriers in close vicinity of the GB center, with either a preference toward interstitials or vacancies which depends on the atomic structure of the boundaries. Finally, using continuous ion bombardment, we investigate the stability of GBs in sever irradiation environment. The results indicate that the sink strength and efficiency of boundaries varies with increasing accumulated defects in GB region. - Highlights: • GBs in hcp Zr are not necessarily biased toward interstitials. • Defect content within bulk depends on PKA energy, PKA distance, and GB texture. • Defect formation energies and diffusion barriers decrease in close vicinity of GBs. • GBs become locally unstable due to absorption of excess defects in ion bombardment.

The direct and indirect benefits of dispositional mindfulness on self-esteem and social anxiety.

Science.gov (United States)

Rasmussen, Michael K; Pidgeon, Aileen M

2011-03-01

The current study investigated relationships between dispositional mindfulness, self-esteem, and social anxiety using self-report measures. Correlational data were collected from 205 Australian undergraduate students who completed the Mindful Attention Awareness Scale (MAAS), the Rosenberg Self-Esteem Scale (RSES), and the Social Interaction Anxiety Scale (SIAS). Mindfulness significantly predicted high levels of self-esteem and low levels of social anxiety. Mediation analysis supported the role of self-esteem as a partial mediator between mindfulness and social anxiety. Clinical implications and suggestions for future research are discussed.

Projekts: SIA Ģimenes centrs" dibināšana

OpenAIRE

Mensaha, Elizabete

2016-01-01

Maģistra darba tēma ir projekts SIA „Ģimenes centrs” dibināšana. Ikviena cilvēka dzīvē ģimene ir pati svarīgākā. Ģimenē veidojas galvenie uzskati par to, kas ir labi vai slikti, pareizi vai nepareizi, godīgi vai negodīgi. Bērni, kuri jau no bērnības dzīvo labvēlīgās ģimenēs, zina, kā veidot labas attiecības savā un savu bērnu ģimenē, zina, kā pārvarēt sadzīviskas vai ikdienišķas problēmas, kuras bieži kļūst par ģimenes šķiršanās iemesliem. Laulības šķiršana ir viena no aktuālākajām mūsdienas ...

SIA "Valrito" apgrozījuma palielināšana

OpenAIRE

Lazdiņš, Ivars

2014-01-01

Maģistra darba mērķis ir izpētīt SIA „Valrito” attīstības iespējas, piedāvājot savam klientam iegādāties jaunu, līdz šim nepiedāvātu produktu līdz 2015. gadam, pielietojot projekta vadīšanas metodes.Darbs ietver uzņēmuma veikalu „Gustiņš” noieta tirgus, produktu un pakalpojumu piedāvājuma, un finanšu rādītāju izpēti, un analīzi. Risinājuma piedāvājumu, kura realizācijai par pamatu tiks ņemts jauna produkta ražošanas uzsākšana.Darba pētījuma ietvaros tiek definēta sekojoša problēma: Uzņēmums ...

Acute interstitial pneumonia

International Nuclear Information System (INIS)

Cuervo M, Francisco; Carrillo Bayona, Jorge; Ojeda, Paulina

2004-01-01

The paper refers to a 71 year-old patient, to who is diagnosed acute interstitial pneumonia; with square of 20 days of evolution of cough dry emetizant, fever, general uneasiness, migraine, progressive dyspnoea and lost of weight

The interstitial pneumonitis induced by cytostatics

International Nuclear Information System (INIS)

Dubrava, M.; Markova, I.; Mistina, L.

1998-01-01

The author presents a cause of 9-year old boy with ALL-F2B in the stage of the prevention treatment where in the its course the induced interstitial pneumonitis by cytostatics was developed. The bacterial, virus, mycological and parasitic causes of the interstitial pneumonitis on the basis of the bronchoscopy, BAL, CT, scintigraphy, laboratory and by cultivation were excluded. (authors)

An approach to interstitial lung disease in India

Directory of Open Access Journals (Sweden)

J N Pande

2014-07-01

Full Text Available Interstitial lung diseases are common and have varied etiology, clinical presentation, clinical course and outcome. They pose a diagnostic challenge to physicians and pulmonologists. Patients present with dry cough, exertional dyspnoea, interstitial lesions on X-ray of the chest and restrictive ventilatory defect on spirometry. A sharp decline in oxygen saturation with exercise is characteristic. Careful evaluation of the history of the patient and physical examination help in narrowing down diagnostic probabilities. HRCT of the chest has emerged as an important tool in the evaluation of these disorders. Idiopathic Interstitial Pneumonias (IIP are a group of conditions which are classified into several types based on pathological features. Bronchoscopic procedures are helpful in diagnosis of certain disorders but are of limited value in classification of IIP which requires surgical biopsy. Usual Interstitial Pneumonia (UIP, also referred to as Idiopathic Pulmonary Fibrosis, has a progressive course and an unfavourable outcome. Certain new drugs have recently become available for treatment of UIP. Our approach towards diagnosis and management of interstitial lung diseases based on personal experience over the past three decades is reported here. Key words: Usual interstitial pneumonia – sarcoidosis – pneumoconiosis – bronchoscopy – lung biopsy 

Lung volumes and emphysema in smokers with interstitial lung abnormalities.

Science.gov (United States)

Washko, George R; Hunninghake, Gary M; Fernandez, Isis E; Nishino, Mizuki; Okajima, Yuka; Yamashiro, Tsuneo; Ross, James C; Estépar, Raúl San José; Lynch, David A; Brehm, John M; Andriole, Katherine P; Diaz, Alejandro A; Khorasani, Ramin; D'Aco, Katherine; Sciurba, Frank C; Silverman, Edwin K; Hatabu, Hiroto; Rosas, Ivan O

2011-03-10

Cigarette smoking is associated with emphysema and radiographic interstitial lung abnormalities. The degree to which interstitial lung abnormalities are associated with reduced total lung capacity and the extent of emphysema is not known. We looked for interstitial lung abnormalities in 2416 (96%) of 2508 high-resolution computed tomographic (HRCT) scans of the lung obtained from a cohort of smokers. We used linear and logistic regression to evaluate the associations between interstitial lung abnormalities and HRCT measurements of total lung capacity and emphysema. Interstitial lung abnormalities were present in 194 (8%) of the 2416 HRCT scans evaluated. In statistical models adjusting for relevant covariates, interstitial lung abnormalities were associated with reduced total lung capacity (-0.444 liters; 95% confidence interval [CI], -0.596 to -0.292; Ppulmonary disease (COPD) (odds ratio, 0.53; 95% CI, 0.37 to 0.76; P<0.001). The effect of interstitial lung abnormalities on total lung capacity and emphysema was dependent on COPD status (P<0.02 for the interactions). Interstitial lung abnormalities were positively associated with both greater exposure to tobacco smoke and current smoking. In smokers, interstitial lung abnormalities--which were present on about 1 of every 12 HRCT scans--were associated with reduced total lung capacity and a lesser amount of emphysema. (Funded by the National Institutes of Health and the Parker B. Francis Foundation; ClinicalTrials.gov number, NCT00608764.).

HRCT of diffuse interstitial pneumonia during treatment

International Nuclear Information System (INIS)

Takahashi, Masashi; Sano, Akira; Imanaka, Kazufumi

1989-01-01

HRCT was carried out in twenty patients with diffuse interstitial pneumonia: 13 cases of IIP, 3 of BOOP, 2 of drug-induced pneumonia, 1 of rheumatoid lung and acute interstitial pneumonia of unknown origin. With special attention to inflammatory activity, the patients underwent HRCT periodically during the treatment. Correlative investigation between HRCT image and grade of accumulation in 67 Ga scintigraphy was also performed. Response to steroid therapy was clearly reflected on HRCT image, that was shown as decreasing pulmonary density or thinning of honeycomb wall. HRCT is considered to be useful in assessing the activity of diffuse interstitial pneumonia. (author)

Bioloģisko aktīvu uzskaite SIA "Lielvircava Agro"

OpenAIRE

Laščenko, Jeļena

2010-01-01

Latvijā bioloģisko aktīvu uzskaites problemātika ir neizpētīts jautājums, gan no zinātnisko pētījumu, gan no regulējuma aspekta. Darba mērķis ir izpētīt SIA „Lielvircava AGRO” piederošo bioloģisko aktīvu uzskaites īpatnības un izstrādāt priekšlikumus bioloģisko aktīvu uzskaites pilnveidošanai. Darba mērķi un uzdevumi tiek atspoguļoti darba divās loģiski saistītās nodaļās, secinājumos un priekšlikumos, literatūras sarakstā, kā arī pielikumos. Darba pirmā nodaļā tiek skaidrots bioloģis...

87Sr/86Sr and 18O/16O ratios, interstitial water chemistry and diagenesis in deep-sea carbonate sediments of the Ontong Java Plateau

International Nuclear Information System (INIS)

Elderfield, H.; Oldfield, R.K.; Hawkesworth, C.J.

1982-01-01

Interstitial waters and sediments from DSDP sites 288 and 289 contain information on the chemistry and diagenesis of carbonate in deep-sea sediments and on the role of volcanic matter alteration processes. Sr/Ca ratios are species dependent in unaltered foraminifera from site 289 and atom ratios exceed those predicted by distribution coefficient data. During diagenesis Sr/Ca ratios of carbonates decrease and reach the theoretical distribution at a depth which is identical to the depth of Sr isotopic equilibration, where 87 Sr/ 86 Sr ratios of interstitial waters and carbonates converge. Mg/Ca ratios in the carbonates do not increase with depth as found in some other DSDP sites, possibly because of diagenetic re-equilibration with interstitial waters showing decreasing Mg 2+ /Ca 2+ ratios with depth due to Ca input and Mg removal by alteration of volcanic matter. Interstitial 18 O/ 16 O ratios increase with depth at site 289 to delta 18 O = 0.67 per thousand (SMOW), reflecting carbonate recrystallization at elevated temperatures, the first recorded evidence of this effect in interstitial waters. Interstitial Sr 2+ concentrations reach high levels, up to 1 mM, chiefly because of carbonate recrystallization. However, 87 Sr/ 86 Sr ratios decrease from 0.7092 to less than 0.7078, lower than for contemporaneous sea water, showing that there is a volcanic input of strontium at depth. (author)

Determinação de baixas concentrações de cobre em águas naturais por espectrofotometria de absorção atômica em chama usando um sistema SIA com uma coluna de poli(etilenimina

Directory of Open Access Journals (Sweden)

Costa Rui Cerdeira de Campos

2001-01-01

Full Text Available This paper describes a sequential injection analysis (SIA set-up coupled to a flame atomic absorption spectrometer (FAAS to accomplish the determination of low concentrations of copper in drinking waters. Copper is first retained under neutral media in an on-line 29x1.6 mm column filled with poly(ethylenimine immobilised on silica gel. The retained analyte is then eluted by flowing through the column 250 mL of a nitric acid solution. The selection of 3.85 ml of sample enabled to obtain a detection limit of 0.27 mug/L and a sampling rate of about 24 samples/h. There was a good agrement between the results of 12 samples furnished by the proposed procedure and by electrothermal atomic absorption spectrometry. Repeatability assessment gave a relative standard deviation of 1.3 % after ten replicate analysis of a sample containing about 70 mug/L in copper..

Computer experiments on the imaging of the (111) split crowdion interstitial in tungsten by transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Krakow, W [Xerox Corp., Rochester, N.Y. (USA)

1978-06-01

Computer simulated dark-field electron micrographs at atomic resolutions have been generated by calculating the diffuse elastic scattering distribution of short range order objects with the important point being that images are formed from regions of reciprocal space that do not contain Bragg reflections of the perfect crystal. Interpretation of these images in terms of atom positions and atom correlations becomes straightforward and it is a simple matter to distinguish between real structural information and image artifacts produced by the phase contrast mechanism in the electron optical imaging process. In this paper images were calculated under a variety of microscope conditions for a (111) split crowdion interstitial in tungsten which included up to 182 atoms of the surrounding strain field. The effect of specimen orientation, microscope objective lens defocus and the contribution of atoms lying in different shells around the defect have been considered. To aid in image interpretation accompanying diffraction patterns have been computed for different specimen orientations which show either the perfect crystal Bragg diffraction pattern or the diffuse scattering distribution produced by the crowdion defect.

A novel self-sensing technique for tapping-mode atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Ruppert, Michael G.; Moheimani, S. O. Reza [The University of Newcastle, University Drive, Callaghan NSW 2308 (Australia)

2013-12-15

This work proposes a novel self-sensing tapping-mode atomic force microscopy operation utilizing charge measurement. A microcantilever coated with a single piezoelectric layer is simultaneously used for actuation and deflection sensing. The cantilever can be batch fabricated with existing micro electro mechanical system processes. The setup enables the omission of the optical beam deflection technique which is commonly used to measure the cantilever oscillation amplitude. Due to the high amount of capacitive feedthrough in the measured charge signal, a feedforward control technique is employed to increase the dynamic range from less than 1 dB to approximately 35 dB. Experiments show that the conditioned charge signal achieves excellent signal-to-noise ratio and can therefore be used as a feedback signal for atomic force microscopy imaging.

Atomic-scale dislocation dynamics in radiation damage environment

International Nuclear Information System (INIS)

Osetsky, Y.; Stoller, R.; Bacon, D.J.

2007-01-01

Full text of publication follows: The dynamics behavior of dislocations determines mechanical properties of crystalline materials. Long-range interactions between a moving dislocation and other defects can be treated within a continuum approach via interaction of their stress and strain fields. However, a vast contribution to mechanical properties depends on the direct interaction between dislocations and other defects and depends very much on the particular atomic scale structure of the both moving dislocation core and the obstacle. In this work we review recent progress in large-scale modeling of dislocation dynamics in metals at the atomic level by molecular dynamics and statics. We review the modem techniques used to simulate dynamics of dislocations in different lattice structures, the dependence on temperature, strain rate and obstacle size. Examples are given for bcc, fcc and hcp metals where edge and screw dislocations interact with vacancy (loops, voids, stacking fault tetrahedra, etc), self-interstitial clusters and secondary phase precipitates. Attention is paid to interpretation of atomistic results from the point of view of parameterization of continuum models. The latter is vitally necessary for further application in 3-dimensional dislocation dynamics within the multi-scale materials modeling approach. Research sponsored by the Division of Materials Sciences and Engineering and the Office of Fusion Energy Sciences, U.S. Department of Energy, under contract DE-AC0S-00OR22725 with UT-Battelle, LLC. (authors)

Nucleation of voids in materials supersaturated with mobile interstitials, vacancies and divacancies

International Nuclear Information System (INIS)

Wolfer, W.G.; Si-Ahmed, A.

1982-01-01

In previous void nucleation theories, the void size has been allowed to change only by one atomic volume through vacancy or interstitial absorption or through vacancy emission. To include the absorption of divacancies, the classical nucleation theory is here extended to include double-step transitions between clusters. The new nucleation theory is applied to study the effect of divacancies on void formation. It is found that the steady-state void nucleation rate is enhanced by several orders of magnitude as compared to results with previous void nucleation theories. However, to obtain void nucleation rates comparable to measured ones, the effect of impurities, segregation and insoluble gases must still be invoked. (author)

Two particle correlations at mid-rapidity in Si+A and Au+Au from E859/E866

International Nuclear Information System (INIS)

Baker, M.D.

1997-01-01

Two particle correlation measurements for Si-A and Au- Au collisions from Brookhaven E859 and E866 are discussed. These measurements allow us, with some interpretation, to deduce the size of the participant region in a heavy ion collision. We show that various source parameterizations yield consistent results and we explore the dependence of the apparent source size on the pion yield

A análise por injeção sequencial (SIA: vinte anos em uma perspectiva brasileira

Directory of Open Access Journals (Sweden)

Allan Cezar Vieira dos Santos

2010-01-01

Full Text Available The year of 2010 marks the 20th anniversary of the development of Sequential Injection Analysis (SIA by Ruzicka and Marshall. Considered the second generation of the flow injection methods, this article briefly describes the history, the basic principles of the technique and reviews all papers developed by Brazilian scientists aiming the divulgation of this automation technique in Analytical Chemistry.

Characterization of the N-Acetyl-5-neuraminic Acid-binding Site of the Extracytoplasmic Solute Receptor (SiaP) of Nontypeable Haemophilus influenzae Strain 2019

Energy Technology Data Exchange (ETDEWEB)

Johnston, Jason W.; Coussens, Nathan P.; Allen, Simon; Houtman, Jon C.D.; Turner, Keith H.; Zaleski, Anthony; Ramaswamy, S.; Gibson, Bradford W.; Apicella, Michael A. (Iowa); (Buck Inst.)

2012-11-14

Nontypeable Haemophilus influenzae is an opportunistic human pathogen causing otitis media in children and chronic bronchitis and pneumonia in patients with chronic obstructive pulmonary disease. The outer membrane of nontypeable H. influenzae is dominated by lipooligosaccharides (LOS), many of which incorporate sialic acid as a terminal nonreducing sugar. Sialic acid has been demonstrated to be an important factor in the survival of the bacteria within the host environment. H. influenzae is incapable of synthesizing sialic acid and is dependent on scavenging free sialic acid from the host environment. To achieve this, H. influenzae utilizes a tripartite ATP-independent periplasmic transporter. In this study, we characterize the binding site of the extracytoplasmic solute receptor (SiaP) from nontypeable H. influenzae strain 2019. A crystal structure of N-acetyl-5-neuraminic acid (Neu5Ac)-bound SiaP was determined to 1.4 {angstrom} resolution. Thermodynamic characterization of Neu5Ac binding shows this interaction is enthalpically driven with a substantial unfavorable contribution from entropy. This is expected because the binding of SiaP to Neu5Ac is mediated by numerous hydrogen bonds and has several buried water molecules. Point mutations targeting specific amino acids were introduced in the putative binding site. Complementation with the mutated siaP constructs resulted either in full, partial, or no complementation, depending on the role of specific residues. Mass spectrometry analysis of the O-deacylated LOS of the R127K point mutation confirmed the observation of reduced incorporation of Neu5Ac into the LOS. The decreased ability of H. influenzae to import sialic acid had negative effects on resistance to complement-mediated killing and viability of biofilms in vitro, confirming the importance of sialic acid transport to the bacterium.

Tumor interstitial fluid

DEFF Research Database (Denmark)

Gromov, Pavel; Gromova, Irina; Olsen, Charlotta J.

2013-01-01

Tumor interstitial fluid (TIF) is a proximal fluid that, in addition to the set of blood soluble phase-borne proteins, holds a subset of aberrantly externalized components, mainly proteins, released by tumor cells and tumor microenvironment through various mechanisms, which include classical...

High-resolution CT of lymphoid interstitial pneumonia

International Nuclear Information System (INIS)

Vilgrain, V.; Frija, J.; Yana, C.; Couderc, L.J.; David, M.; Clauvel, J.P.; Laval-Jeantet, M.

1989-01-01

Three patients with lymphoid interstitial pneumonia (two HIV 1+ patients with chronic lymphadenopathic syndromes and one with a not-characterized autoimmune disease) have been studied with high-resolution computed tomography (HR-CT). This technique reveals septal lines, small reticulonodular opacities, polyhedral micronodular opacities, 'ground-glass' opacities and a dense, subpleural, curved broken line in one patient. The lesions dominate in the bases of the lungs. They are not characteristic for lymphoid interstitial pneumonia. If a patient presents with a chronic lymphadenopathic syndrome, the diagnosis of an opportunistic infection should not be automatically made, since the syndrome can be caused by lymphoid interstitial pneumonia [fr

A comparison in cosmetic outcome between per-operative interstitial breast implants and delayed interstitial breast implants after external beam radiotherapy

NARCIS (Netherlands)

Pieters, Bradley R.; Hart, Augustinus A. M.; Russell, Nicola S.; Jansen, Edwin P. M.; Peterse, Johannes L.; Borger, Jacques; Rutgers, Emiel J. Th

2003-01-01

Background and purpose: Interstitial implants for brachytherapy boost in the breast conserving therapy of breast cancer can be performed in two ways; implants during the tumor excision (per-operative implants) or after the external beam therapy (delayed interstitial implants). Differences in

Interstitial lung diseases with fibrosis - the pattern at high resolution

International Nuclear Information System (INIS)

Jarzemska, A.; Lasek, W.; Nawrocka, E.; Meder, G.; Zapala, M.

2003-01-01

Surgical lung biopsy, either open thoracotomy or video-assisted thoracoscopy is recommended in the diagnosis of interstitial lung diseases (ILD). In some cases, however, the repetitive pattern of radiological features in high-resolution computed tomography is often sufficient to confirm the diagnosis in a non-invasive manner. The purpose of the study was to determine whether patients with ILD can be selected on the basis of the HRCT pattern. Thin-section CT scans were performed in 40 patients with histologically proven idiopathic interstitial pneumonia (26 patients with usual interstitial pneumonia UIP, 2 patients with desquamative interstitial pneumonia DIP, 2 patients with bronchiolitis obliterans organizing pneumonia BOOP, 2 patients with non-specific interstitial pneumonia NSIP, 11 patients with hypersensitivity pneumonitis, and 3 patients with pulmonary histiocytosis X). The location and the intensity of lesions were taken into consideration. Clinical and histopathological findings were compared. HRCT features of interstitial lung diseases such as nodules and cystic spaces in hypersensitivity pneumonitis and pulmonary histiocytosis, and ground-glass opacities in idiopathic interstitial pneumonias (IIP) were statistically significant for differential diagnosis in ILD cases. Combination of honeycombing and ground-glass opacities found in UIP and nodules found in DIP were also statistically significant features in IIP subtypes diagnosis. In some cases, HRCT patterns of hypersensitivity pneumonitis, pulmonary histiocytosis X and IPF combined with clinical findings allowed for the accurate diagnosis without resorting to lung biopsy. Within a group of idiopathic interstitial pneumonia only in usual interstitial pneumonia characteristic pattern in thin-section CT can be defined. In other subgroups some typical features can imply a diagnosis. (author)

Passado e presente: Sicília e Mileto, Roma e Afrodísias no romance de Cáriton

Directory of Open Access Journals (Sweden)

Adriane da Silva Duarte

2016-03-01

Full Text Available Quéreas e Calírroe, romance de Cáriton de Afrodísias (I d.C., tem como ponto de partida e de retorno do par protagonista a cidade de Siracusa, na Sicília do início do século IV a.C.. Uma parte considerável da ação, contudo, se passa em Mileto, para onde se desloca a heroína. Procura-se investigar aqui as razões dessa opção de Cáriton, que já na primeira sentença de sua obra proclama sua nacionalidade, alertando o leitor que o autor é um grego que vive na periferia do império romano. A hipótese é que a escolha por situar a ação do romance no passado reflita menos a emulação do relato historiográfico, especialmente o de Tucídides, mas antes uma estratégia para tratar indiretamente da relação entre Afrodísias e Roma no presente.

Training activities and perspectives in the radioactive waste management area of Moscow SIA 'Radon' - 16131

International Nuclear Information System (INIS)

Batyukhnova, O.G.; Arustamov, A.E.; Dmitriev, S.A.; Arustamova, N.A.; Ojovan, M.; Drace, Z.

2009-01-01

The education service for specialists dealing with radioactive waste was established in Russia (former USSR) in 1983 and was based on the capabilities of two organisations: Moscow Scientific and Industrial Association 'Radon' (SIA 'Radon') and Lomonosov's Moscow State University. These two organizations are able jointly to offer training programs in the science fundamentals, applied research and in practical operational areas of the all pre-disposal activities of the radioactive waste management (RWM). Since 1997 this system was upgraded to the international level and now acts as the International Education Training Centre (IETC) at SIA 'Radon' under the guidance of the IAEA. During last 12 years more than 350 specialists from 33 European and Asian countries enhanced their knowledge and skills in RWM. The IAEA supported many specialized regional training courses and workshops, fellowships, on-the-job training, and scientific visits which are additional means to assure development of personnel capabilities. Efficiency of training was analysed at IETC using the structural adaptation of educational process as well as factors, which have influence on education quality. In addition social-psychological aspects were also taken into account in assessing the overall efficiency. The analysis of the effect of individual factors and the efficiency of education activity were carried out based on appraisal results and post-course questioning of attendees. (authors)

Mid-term evaluation of the Climate Change Action Fund: Science, Impacts and Adaptation (SIA) block

International Nuclear Information System (INIS)

2001-11-01

In 1998, the Climate Change Action Fund was established by the Government of Canada. Its budget represented 150 million dollars over a three year period, and was an additional 625 million dollars in the federal budget of February 2000 was allocated for climate change initiatives, of which 150 million dollars were earmarked over a three year period to the Climate Change Action Fund. To provide input for Treasury Board Submissions looking for funding approval in the future, it was necessary to conduct a mid-term evaluation focused on program performance to date. The period covered by the evaluation was September 2000 to the end of January 2001. This report examined the performance of the Science, Impact and Adaptation Block (SIA). Based on a series of interviews with representatives of Block managers, Technical and Executive Policy Committees, successful applicants, unsuccessful applicants and peer reviewers, as well as a review of the documentation maintained by SIA, it addressed the following issues: Block relevance, progress/success to date, and effectiveness in meeting the objectives. It was determined that the objectives displayed relevance to the climate change agenda of the federal government, progress to date was considered satisfactory, and most of the objectives should be met in a timely fashion. A summary of the findings was included in this document along with recommendations pertaining to the findings. 3 tabs., 1 fig

In-situ observation of atomic self-organization processes in Xe nanocrystals embedded in Al

International Nuclear Information System (INIS)

Mitsuishi, K.; Song, M.; Furuya, K.; Birtcher, R. C.; Allen, C. W.; Donnelly, S. E.

1998-01-01

Self-organization processes in Xe nanocrystals embedded in Al are observed with in-situ high-resolution electron microscopy. Under electron irradiation, stacking fault type defects are produced in Xe nanocrystals. The defects recover in a layer by layer manner. Detailed analysis of the video reveals that the displacement of Xe atoms in the stacking fault was rather small for the Xe atoms at boundary between Xe and Al, suggesting the possibility of the stacking fault in Xe precipitate originating inside of precipitate, not at the Al/Xe interface

Measurements of T0 temperatures of supersaturated Si-As alloys

International Nuclear Information System (INIS)

Lee, K.R.; West, J.A.; Smith, P.M.; Aziz, M.J.

1992-01-01

In this paper the congruent melting point, or T 0 curve, of crystalline Si-As alloys has been measured in the range of 1.6 to 18.1 at.% arsenic by line source electron beam annealing. Alloys were created by ion implantation of as into 0.1 mm Si-on-sapphire and crystallized by pulsed laser melting. T 0 temperatures decrease form 1673 ± 10K at 2.0 at.% As to 1516 ± 30K at 18.1 at.% As. The results of these measurements are significantly higher than the previous results of studies using pulsed laser melting techniques. Advantages of the e-beam technique over previous techniques are discussed. Chemical free energy functions of the solid and liquid phases were calculated from existing thermodynamic data. The calculated T 0 curve agrees with the measured values only in low concentration region (less than 8 at.%)

Self-consistent average-atom scheme for electronic structure of hot and dense plasmas of mixture

International Nuclear Information System (INIS)

Yuan Jianmin

2002-01-01

An average-atom model is proposed to treat the electronic structures of hot and dense plasmas of mixture. It is assumed that the electron density consists of two parts. The first one is a uniform distribution with a constant value, which is equal to the electron density at the boundaries between the atoms. The second one is the total electron density minus the first constant distribution. The volume of each kind of atom is proportional to the sum of the charges of the second electron part and of the nucleus within each atomic sphere. By this way, one can make sure that electrical neutrality is satisfied within each atomic sphere. Because the integration of the electron charge within each atom needs the size of that atom in advance, the calculation is carried out in a usual self-consistent way. The occupation numbers of electron on the orbitals of each kind of atom are determined by the Fermi-Dirac distribution with the same chemical potential for all kinds of atoms. The wave functions and the orbital energies are calculated with the Dirac-Slater equations. As examples, the electronic structures of the mixture of Au and Cd, water (H 2 O), and CO 2 at a few temperatures and densities are presented

Self-consistent average-atom scheme for electronic structure of hot and dense plasmas of mixture.

Science.gov (United States)

Yuan, Jianmin

2002-10-01

An average-atom model is proposed to treat the electronic structures of hot and dense plasmas of mixture. It is assumed that the electron density consists of two parts. The first one is a uniform distribution with a constant value, which is equal to the electron density at the boundaries between the atoms. The second one is the total electron density minus the first constant distribution. The volume of each kind of atom is proportional to the sum of the charges of the second electron part and of the nucleus within each atomic sphere. By this way, one can make sure that electrical neutrality is satisfied within each atomic sphere. Because the integration of the electron charge within each atom needs the size of that atom in advance, the calculation is carried out in a usual self-consistent way. The occupation numbers of electron on the orbitals of each kind of atom are determined by the Fermi-Dirac distribution with the same chemical potential for all kinds of atoms. The wave functions and the orbital energies are calculated with the Dirac-Slater equations. As examples, the electronic structures of the mixture of Au and Cd, water (H2O), and CO2 at a few temperatures and densities are presented.

Formation and migration properties of the rare gases He, Ne, Ar, Ke, and Xe in nickel

International Nuclear Information System (INIS)

Melius, C.F.; Wilson, W.D.; Bisson, C.L.

1980-01-01

The energies of formation and migration of various rare gas-point defect complexes in an f.c.c. nickel lattice have been calculated for He, Ne, Ar, Kr, and Xe. Formation energies of rare gas atoms at interstitial sites are compared with those in substitutional sites. Binding energies are presented for self-interstitials and vacancies trapped to the various rare gas substitutionals. Migration energies and migration paths are also presented for various rare gas interstitials and substitutionals with and without trapped vacancies and self-interstitials. The migration energies are compared with the breakup energies for the corresponding complexes. It is found that divacancy-rare gas complexes are rather stable and will migrate at relatively low energies compared to other substitutional rare gas migration processes. (author)

Leflunomide-Induced Interstitial Lung Disease: A Case Report

Directory of Open Access Journals (Sweden)

Aygül Güzel

2015-04-01

Full Text Available Leflunomide (LEF induced interstitial pneumonitis is a very rare condition but potentially fatal. We report a case of LEF induced interstitial pneumonitis. A 63-year-old woman followed-up for 37 years with the diagnosis of rheumatoid arthritis treated with LEF (20 mg/day since 5 months were admitted to our hospital with cough, dyspnea, fever, and dark sputum.Chest radiography represented bilateral alveolar consolidation. High-resolution computed tomography demonstrated diffuse ground-glass appearance and interlobular septal thickening. Since the patient’s clinics and radiologic findings improved dramatically after the cessation of LEF and recieving oral steriod therapy, she was diagnosed as drug-induced interstitial lung disease. In conclusion, when nonspecific clinical signs such as respiratory distress, cough and fever seen during the use of LEF, drug-induced interstitial lung disease should be kept in mind for the differantial diagnosis.

Self-Regular Black Holes Quantized by means of an Analogue to Hydrogen Atoms

Directory of Open Access Journals (Sweden)

Chang Liu

2016-01-01

Full Text Available We suggest a quantum black hole model that is based on an analogue to hydrogen atoms. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of nonextreme black holes are given by the probability densities of excited states with no angular momenta. Such an analogue is inclined to adopt quantization of black hole horizons. In this way, the total mass of black holes is quantized. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.

Interstitial integrals in the multiple-scattering model

International Nuclear Information System (INIS)

Swanson, J.R.; Dill, D.

1982-01-01

We present an efficient method for the evaluation of integrals involving multiple-scattering wave functions over the interstitial region. Transformation of the multicenter interstitial wave functions to a single center representation followed by a geometric projection reduces the integrals to products of analytic angular integrals and numerical radial integrals. The projection function, which has the value 1 in the interstitial region and 0 elsewhere, has a closed-form partial-wave expansion. The method is tested by comparing its results with exact normalization and dipole integrals; the differences are 2% at worst and typically less than 1%. By providing an efficient means of calculating Coulomb integrals, the method allows treatment of electron correlations using a multiple scattering basis set

Deletion of 7q33-q35 in a Patient with Intellectual Disability and Dysmorphic Features: Further Characterization of 7q Interstitial Deletion Syndrome

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Kristen Dilzell

2015-01-01

Full Text Available This case report concerns a 16-year-old girl with a 9.92 Mb, heterozygous interstitial chromosome deletion at 7q33-q35, identified using array comparative genomic hybridization. The patient has dysmorphic facial features, intellectual disability, recurrent infections, self-injurious behavior, obesity, and recent onset of hemihypertrophy. This patient has overlapping features with previously reported individuals who have similar deletions spanning the 7q32-q36 region. It has been difficult to describe an interstitial 7q deletion syndrome due to variations in the sizes and regions in the few patients reported in the literature. This case contributes to the further characterization of an interstitial distal 7q deletion syndrome.

Dysthanasia: nursing professionals' perception Distanasia: percepción de los profesionales de enfermería Distanásia: percepção dos profissionais da enfermagem

Directory of Open Access Journals (Sweden)

Milene Barcellos de Menezes

2009-08-01

Full Text Available Dysthanasia means slow and painful death without quality of life. This study aimed to know whether nurses identify dysthanasia as part of the final process of the lives of terminal patients hospitalized at an adult ICU. This is an exploratory-qualitative study. Data were collected through semi-structured interviews with ten nurses with at least one year of experience in an ICU, and interpreted through content analysis. Results indicate that nurses understand and identify dysthanasia, do not agree with it and recognize elements of orthonasia as the adequate procedure for terminal patients. We conclude that nurses interpret dysthanasia as extending life with pain and suffering, while terminal patients are submitted to futile treatments that do not benefit them. They also identify dysthanasia using elements of orthonasia to explain it.Distanasia significa muerte lenta, con sufrimiento y sin calidad de vida. En esta investigación se buscó conocer si los enfermeros identifican la distanasia como parte del proceso final de la vida de personas en estado terminal, internadas en una UTI para adultos. El estudio es de naturaleza exploratoria, con abordaje cualitativo. Los datos fueron recolectados por medio de entrevista semiestructurada con 10 enfermeros con un mínimo de un año de experiencia en UTI; los datos fueron interpretados por el análisis de contenido. Se obtuvo como resultado que los enfermeros comprenden e identifican la distanasia y se oponen a la misma, presentando elementos de ortotanasia como procedimiento adecuado para pacientes en estado terminal. Se concluye que los enfermeros interpretan la distanasia como el prolongamiento de la vida con dolor y sufrimiento, en el cual los pacientes terminales son sometidos a tratamientos fútiles que no traen beneficios. También identifican la distanasia, usando elementos de la ortotanasia para hacerla explicita.Distanásia significa morte lenta, sofrida e sem qualidade de vida. Nesta pesquisa

Smoking-related interstitial lung diseases; Interstitielle Lungenerkrankungen bei Rauchern

Energy Technology Data Exchange (ETDEWEB)

Marten, K. [Technische Univ. Muenchen (Germany). Klinikum rechts der Isar, Inst. fuer Roentgendiagnostik

2007-03-15

The most important smoking-related interstitial lung diseases (ILD) are respiratory bronchiolitis, respiratory bronchiolitis-associated interstitial lung disease, desquamative interstitial pneumonia, and Langerhans' cell histiocytosis. Although traditionally considered to be discrete entities, smoking-related ILDs often coexist, thus accounting for the sometimes complex patterns encountered on high-resolution computed tomography (HRCT). Further studies are needed to elucidate the causative role of smoking in the development of pulmonary fibrosis.

Analysis of Dissolved Organic Nutrients in the Interstitial Water of Natural Biofilms.

Science.gov (United States)

Tsuchiya, Yuki; Eda, Shima; Kiriyama, Chiho; Asada, Tomoya; Morisaki, Hisao

2016-07-01

In biofilms, the matrix of extracellular polymeric substances (EPSs) retains water in the interstitial region of the EPS. This interstitial water is the ambient environment for microorganisms in the biofilms. The nutrient condition in the interstitial water may affect microbial activity in the biofilms. In the present study, we measured the concentrations of dissolved organic nutrients, i.e., saccharides and proteins, contained in the interstitial water of biofilms formed on the stones. We also analyzed the molecular weight distribution, chemical species, and availability to bacteria of some saccharides in the interstitial water. Colorimetric assays showed that the concentrations of saccharides and proteins in the biofilm interstitial water were significantly higher (ca. 750 times) than those in the surrounding lake waters (p Chromatographic analyses demonstrated that the saccharides in the interstitial waters were mainly of low molecular-weight saccharides such as glucose and maltose, while proteins in the interstitial water were high molecular-weight proteins (over 7000 Da). Bacterial growth and production of EPS occurred simultaneously with the decrease in the low molecular-weight saccharide concentrations when a small portion of biofilm suspension was inoculated to the collected interstitial water, suggesting that the dissolved saccharides in the interstitial water support bacterial growth and formation of biofilms.

Interstitial Fluid Flow: The Mechanical Environment of Cells and Foundation of Meridians

Directory of Open Access Journals (Sweden)

Wei Yao

2012-01-01

Full Text Available Using information from the deep dissection, microobservation, and measurement of acupoints in the upper and lower limbs of the human body, we developed a three-dimensional porous medium model to simulate the flow field using FLUENT software and to study the shear stress on the surface of interstitial cells (mast cells caused by interstitial fluid flow. The numerical simulation results show the following: (i the parallel nature of capillaries will lead to directional interstitial fluid flow, which may explain the long interstitial tissue channels or meridians observed in some experiments; (ii when the distribution of capillaries is staggered, increases in the velocity alternate, and the velocity tends to be uniform, which is beneficial for substance exchange; (iii interstitial fluid flow induces a shear stress, with magnitude of several Pa, on interstitial cell membranes, which will activate cells and lead to a biological response; (iv capillary and interstitial parameters, such as capillary density, blood pressure, capillary permeability, interstitial pressure, and interstitial porosity, affect the shear stress on cell surfaces. The numerical simulation results suggest that in vivo interstitial fluid flow constitutes the mechanical environment of cells and plays a key role in guiding cell activities, which may explain the meridian phenomena and the acupuncture effects observed in experiments.

On grain size dependent void swelling in pure copper irradiated with fission neutrons

International Nuclear Information System (INIS)

Singh, B.N.; Eldrup, M.; Golubov, S.I.; Zinkle, S.J.

2001-03-01

The effect of grain size on void swelling has its origin in the intrinsic property of grain boundaries as neutral and unsaturable sinks for both vacancies and self-interstitial atoms (SIAs). The phenomenon was investigated already in the 1970s and it was demonstrated that the grain size dependent void swelling measured under irradiation producing only Frenkel pairs could be satisfactorily explained in terms of the standard rate theory (SRT) and dislocation bias. Experimental results reported in the 1980s demonstrated, on the other hand, that the effect of grain boundaries on void swelling under cascade damage conditions was radically different and could not be explained in terms of the SRT. In an effort to understand the source of this significant difference, the effect of grain size on void swelling under cascade damage conditions has been investigated both experimentally and theoretically in pure copper irradiated with fission neutrons at 623K to a dose level of ∼0.3 dpa (displacement per atom). The post-irradiation defect microstructure including voids was investigated using transmission electron microscopy and positron annihilation spectroscopy. The evolution of void swelling was calculated within the framework of the production bias model (PBM) and the SRT. The grain size dependent void swelling measured experimentally is in good accord with the theoretical results obtained using PMB. Implications of these results on modeling of void swelling under cascade damage conditions are discussed. (au)

[Nonspecific interstitial pneumonitis: a clinicopathologic entity, histologic pattern or unclassified group of heterogeneous interstitial pneumonitis?].

Science.gov (United States)

Morais, António; Moura, M Conceição Souto; Cruz, M Rosa; Gomes, Isabel

2004-01-01

Nonspecific interstitial pneumonitis (NSIP) initially described by Katzenstein and Fiorelli in 1994, seems to be a distinct clinicopathologic entity among idiopathic interstitial pneumonitis (IIP). Besides different histologic features from other IIP, NSIP is characterized by a better long-term outcome, associated with a better steroids responsiveness than idiopathic pulmonar fibrosis (IPF), where usually were included. Thus, differentiating NSIP from other IIP, namely IPF is very significant, since it has important therapeutic and prognostic implications. NSIP encloses different pathologies, namely those with inflammatory predominance (cellular subtype) or fibrous predominance (fibrosing subtype). NSIP is reviewed and discussed by the authors, after two clinical cases description.

The self-splitting atom

International Nuclear Information System (INIS)

Trenn, T.J.

1977-01-01

The book describes the collaboration between Ernest Rutherford and Frederick Soddy at McGill University on the study of radioactivity. Their hypothesis of spontaneous atomic disintegration, which represented the first case of an atomic process completely specified in its time relationships by a probability constant, was extremely fruitful. This concept became the paradigm of a host of other quantized processes in high-energy or elementary particle physics involving a single system in isolation. This achievement did not emerge in a single moment of inspiration but passed dialectically through several, not always coherent, stages of experiment and theory. Hitherto unpublished material has been incorporated in the account, including evidence from the original laboratory notebooks. (U.K.)

Framework 'interstitial' oxygen in La10(GeO4)5-(GeO5)O2 apatite electrolyte

International Nuclear Information System (INIS)

Pramana, S.S.; White, T.J.

2007-01-01

Oxygen conduction at low temperatures in apatites make these materials potentially useful as electrolytes in solid-oxide fuel cells, but our understanding of the defect structures enabling ion migration is incomplete. While conduction along [001] channels is dominant, considerable inter-tunnel mobility has been recognized. Using neutron powder diffraction of stoichiometric 'La 10 (GeO 4 ) 6 O 3 ', it has been shown that this compound is more correctly described as an La 10 (GeO 4 ) 5- (GeO 5 )O 2 apatite, in which high concentrations of interstitial oxygen reside within the channel walls. It is suggested that these framework interstitial O atoms provide a reservoir of ions that can migrate into the conducting channels of apatite, via a mechanism of inter-tunnel oxygen diffusion that transiently converts GeO 4 tetrahedra to GeO 5 distorted trigonal bipyramids. This structural modification is consistent with known crystal chemistry and may occur generally in oxide apatites. (orig.)

Electronic structure of thin films by the self-consistent numerical-basis-set linear combination of atomic orbitals method: Ni(001)

International Nuclear Information System (INIS)

Wang, C.S.; Freeman, A.J.

1979-01-01

We present the self-consistent numerical-basis-set linear combination of atomic orbitals (LCAO) discrete variational method for treating the electronic structure of thin films. As in the case of bulk solids, this method provides for thin films accurate solutions of the one-particle local density equations with a non-muffin-tin potential. Hamiltonian and overlap matrix elements are evaluated accurately by means of a three-dimensional numerical Diophantine integration scheme. Application of this method is made to the self-consistent solution of one-, three-, and five-layer Ni(001) unsupported films. The LCAO Bloch basis set consists of valence orbitals (3d, 4s, and 4p states for transition metals) orthogonalized to the frozen-core wave functions. The self-consistent potential is obtained iteratively within the superposition of overlapping spherical atomic charge density model with the atomic configurations treated as adjustable parameters. Thus the crystal Coulomb potential is constructed as a superposition of overlapping spherically symmetric atomic potentials and, correspondingly, the local density Kohn-Sham (α = 2/3) potential is determined from a superposition of atomic charge densities. At each iteration in the self-consistency procedure, the crystal charge density is evaluated using a sampling of 15 independent k points in (1/8)th of the irreducible two-dimensional Brillouin zone. The total density of states (DOS) and projected local DOS (by layer plane) are calculated using an analytic linear energy triangle method (presented as an Appendix) generalized from the tetrahedron scheme for bulk systems. Distinct differences are obtained between the surface and central plane local DOS. The central plane DOS is found to converge rapidly to the DOS of bulk paramagnetic Ni obtained by Wang and Callaway. Only a very small surplus charge (0.03 electron/atom) is found on the surface planes, in agreement with jellium model calculations

Strain field due to self-interstitial impurity in Ni

Indian Academy of Sciences (India)

The embedded-atom method have been applied to study the strain field ... coordinates which are essentially the Fourier inverses of the direct space ..... stiffness, low coefficient of thermal expansion and chemical compatibility in a variety of.

O Paquistão e as estratégias ocidentais para a Ásia Meridional

Directory of Open Access Journals (Sweden)

Abelardo Arantes Júnior

2003-06-01

Full Text Available Confrontadas com o risco de guerra nuclear entre o Paquistão e a Índia, as potências ocidentais têm procurado exercer algum controle sobre os acontecimentos no Sul da Ásia; instaram os dois países a encetar negociações bilaterais, promoveram a não-proliferação e aplicaram sanções de tempos em tempos. O Paquistão é muito sensível às políticas ocidentais, sobretudo às dos Estados Unidos, porém nunca abriu mão de dois critérios fundamentais de sua política externa: a exigência de autodeterminação para a Cachemira e a dissuasão nuclear. Os Estados Unidos agora mostram um poder e uma influência incontrastáveis, mas após a crise do Iraque a unidade das grandes potências revela fissuras. Ao mesmo tempo, o retorno ao regime civil e parlamentar no Paquistão aumenta a força dos partidos nacionalistas e islâmicos, que querem conter a influência dos Estados Unidos e ampliar os laços com a França, a Alemanha, a Rússia e a China. Nesse novo e fluido ambiente político, a evolução das relações entre o Paquistão e a Índia terá forte impacto sobre as estratégias ocidentais para o Sul da Ásia e para o mundo em geral.Faced with the risk of a nuclear conflict between Pakistan and India, the Western powers have tried to exert a measure of control upon events in South Asia; they urged those two countries to start bilateral negotiations, promoted non-proliferation, and from time to time applied sanctions. Pakistan is very sensitive to Western policies, above all those of the United States, but it never gave up two fundamental criteria of its foreign policy: the demand of self-determination for Kashmir and nuclear deterrence. The United States now shows unmatched power and influence, but after the Iraqi crisis the unity of the great powers became shaky. At the same time the return to a civilian and parliamentarian regime in Pakistan added strength to the nationalist and Islamic parties, which want to contain United States

Automated washing of FTA Card punches and PCR setup for reference samples using a LIMS-controlled Sias Xantus automated liquid handler

DEFF Research Database (Denmark)

Stangegaard, Michael; Olsen, Addie Nina; Frøslev, Tobias G.

2009-01-01

We have implemented and validated automated methods for washing FTA Card punches containing buccal samples and subsequent PCR setup using a Sias Xantus automated liquid handler. The automated methods were controlled by worklists generated by our LabWare Laboratory Information Management System...

Lingots et couteaux en fer d'Alésia. Études archéométriques de pièces inédites

Czech Academy of Sciences Publication Activity Database

Pleiner, Radomír; Fluzin, P.; Mangin, M.; Billon, M.; Dillmann, P.; Vega, E.; Rabeisen, E.

2003-01-01

Roč. 52, - (2003), s. 91-130 ISSN 1266-7706 Institutional research plan: CEZ:AV0Z8002910 Keywords : lingots * knives * metallography * oppidum * Alésia Subject RIV: AC - Archeology, Anthropology, Ethnology

Advanced sickle cell associated interstitial lung disease presenting ...

African Journals Online (AJOL)

Previous studies have reported abnormal pulmonary function and pulmonary hypertension among Nigerians with sickle cell disease, but there is no report of interstitial lung disease among them. We report a Nigerian sickle cell patient who presented with computed tomography proven interstitial lung disease complicated by ...

Interstitial impurity interactions and dislocation microdynamics in Mo crystals

International Nuclear Information System (INIS)

Kwok, D.N.

1975-05-01

The effects of interstitial impurities on the mechanical properties of molybdenum are explored by comparing results obtained for crystals of various interstitial contents controlled by ultra-high vacuum outgassing. Results show a modulus reduction for as-grown samples and for outgassed specimens at low applied stresses. As a function of plastic microstrain, the values of modulus defect for both as-grown and outgassed specimens saturate at the same value. Interstitial impurities act as pinning agents to dislocation bowing, but when all the easy dislocation loops have broken away from local interstitial pins, the modulus defect reaches a constant saturation value. Etch pitting techniques were used to correlate microstrain observations with dislocation generation and motion. It has been found that edge dislocation generation and movement are active in the microstrain region while screw dislocations are relatively inactive until the macrostrain region is reached. Dislocation velocities range from 10 -6 to 10 -3 cm/s and the average distance between interstitial impurity pinning points is found to be approximately 8 x 10 -4 cm. (U.S.)

Effects of γ irradiation of hydra: elimination of interstitial cells from viable hydra

International Nuclear Information System (INIS)

Fradkin, M.; Kakis, H.; Campbell, R.D.

1978-01-01

Hydra attenuata and H. magnipapillata were γ-irradiated from a cesium source. All doses which had any observable effect (3000 rad and above) resulted in a reduction in the number of interstitial cells and of their differentiated product cells, or in the complete elimination of these cells. Interstitial cells were essentially completely eliminated within 5 days after irradiation doses above 5500 rad, and these hydra died. Irradiation doses of 4200 to 5500 rad resulted in a mixture of effects: some hydra recovered completely, some lost all interstitial cells and died, and some lost interstitial cells but could be propagated, as asexually reproducing clones, by hand feeding them. Hydra of some of these hand-fed clones entirely lacked interstitial cells and did not recover interstitial cells during subsequent culturing. Yet when these hydra were repopulated by interstitial cells from a normal hydra, they were restored to normal. Nerve cells became depleted more slowly than interstitial cells following irradiation, so animals can be obtained which possess nerve but no stem (interstitial) cells. The nerve cells and other derivatives of interstitial cells eventually disappear upon prolonged culture of the hydra. Thus γ irradiation can be used to eliminate interstitial cells from hydra, leaving viable polyps composed only of epithelial cells

Selective Uterine Artery Embolization for Management of Interstitial Ectopic Pregnancy

International Nuclear Information System (INIS)

Yang, Seung Boo; Lee, Sang Jin; Joe, Hwan Sung; Goo, Dong Erk; Chang, Yun Woo; Kim, Dong Hun

2007-01-01

Interstitial pregnancy is defined as any gestation that develops in the uterine portion of the fallopian tubes lateral to the round ligament. Interstitial pregnancies account for 2-4% of all ectopic pregnancies and have been reported to have an associated 2% to 2.5% maternal mortality rate. The traditional treatment for interstitial pregnancy using surgical cornual resection may cause infertility or uterine rupture in subsequent pregnancies. Recently, the early identification of intact interstitial pregnancy has been made possible in many cases with high resolution transvaginal ultrasound as well as more sensitive assays for betahuman chorionic gonadotropin (β-hCG). The treatment includes: hysteroscopic transcervical currettage, local and systemic methotrexate (MTX) therapy and prostaglandin or potassium chloride injection of the ectopic mass under sonographic guidance. We describe a case of successful treatment of interstitial pregnancy using uterine artery embolization, after failure of methotrexate treatment

Selective Uterine Artery Embolization for Management of Interstitial Ectopic Pregnancy

Energy Technology Data Exchange (ETDEWEB)

Yang, Seung Boo; Lee, Sang Jin; Joe, Hwan Sung; Goo, Dong Erk; Chang, Yun Woo [Soonchunhyang University Gumi Hospital, Gumi (Korea, Republic of); Kim, Dong Hun [Chosun University Hospital, Gwangju (Korea, Republic of)

2007-04-15

Interstitial pregnancy is defined as any gestation that develops in the uterine portion of the fallopian tubes lateral to the round ligament. Interstitial pregnancies account for 2-4% of all ectopic pregnancies and have been reported to have an associated 2% to 2.5% maternal mortality rate. The traditional treatment for interstitial pregnancy using surgical cornual resection may cause infertility or uterine rupture in subsequent pregnancies. Recently, the early identification of intact interstitial pregnancy has been made possible in many cases with high resolution transvaginal ultrasound as well as more sensitive assays for betahuman chorionic gonadotropin ({beta}-hCG). The treatment includes: hysteroscopic transcervical currettage, local and systemic methotrexate (MTX) therapy and prostaglandin or potassium chloride injection of the ectopic mass under sonographic guidance. We describe a case of successful treatment of interstitial pregnancy using uterine artery embolization, after failure of methotrexate treatment.

Dynamics of production of iodine atoms by dissociation of iodides in a pulsed self-sustained discharge

International Nuclear Information System (INIS)

Vagin, Nikolai P; Kochetov, Igor' V; Napartovich, A P; Yuryshev, Nikolai N

2013-01-01

Absorption at the laser transition has been used for the first time to assess the evolution of concentration of iodine atoms in a pulsed self-sustained discharge in mixtures of iodides with a buffer gas such as molecular nitrogen and helium. Dynamics of the iodine atom production is studied by the method of absorption spectroscopy. The dissociation of C n F 2n+1 I and CnH 2n+1 I (n = 1, 2) iodides is investigated. The energy required to produce atomic iodine is evaluated. The experimental data obtained for CF 3 I are compared with the results of numerical simulations, their reasonable agreement being demonstrated. (active media)

Izmaksu un ieņēmumu klasifikācija un analīze mediju aģentūrā SIA "Carat"

OpenAIRE

Ozoliņa, Evita

2013-01-01

Diplomdarba tēma ir „Izmaksu un ieņēmumu klasifikācija un analīze mediju aģentūrā SIA „Carat””. Katrai Latvijas sabiedrībai (uzņēmumam) ir svarīgi apzināties tās ražošanas izmaksas, veikt šo izmaksu uzskaiti, iegrāmatošanu un turpmāko plānošanu ilgtermiņā. Reklāma ir ietekmīgs sabiedrības preces, pakalpojuma un citu objektu popularizēšanas līdzeklis. Tā kā Latvijā ekonomiskās lejupslīdes gados strauji kritās reklāmas tirgus, darba autorei ir aktuāli raksturot, pētīt un analizēt SIA „Car...

Your atomic self the invisible elements that connect you to everything else in the Universe

CERN Document Server

Stager, Curt

2014-01-01

What do atoms have to do with your life? In Your Atomic Self, scientist Curt Stager reveals how they connect you to some of the most amazing things in the universe. You will follow your oxygen atoms through fire and water and from forests to your fingernails. Hydrogen atoms will wriggle into your hair and betray where you live and what you have been drinking. The carbon in your breath will become tree trunks, and the sodium in your tears will link you to long-dead oceans. The nitrogen in your muscles will help to turn the sky blue, the phosphorus in your bones will help to turn the coastal waters of North Carolina green, the calcium in your teeth will crush your food between atoms that were mined by mushrooms, and the iron in your blood will kill microbes as it once killed a star. You will also discover that much of what death must inevitably do to your body is already happening among many of your atoms at this very moment and that, nonetheless, you and everyone else you know will always exist somewhere in ...

Metastable and bistable defects in silicon

International Nuclear Information System (INIS)

Mukashev, Bulat N; Abdullin, Kh A; Gorelkinskii, Yurii V

2000-01-01

Existing data on the properties and structure of metastable and bistable defects in silicon are analyzed. Primary radiation-induced defects (vacancies, self-interstitial atoms, and Frenkel pairs), complexes of oxygen, carbon, hydrogen, and other impurity atoms and defects with negative correlation energy are considered. (reviews of topical problems)

Desquamative interstitial pneumonia: A case report

Directory of Open Access Journals (Sweden)

Lovrenski Aleksandra

2014-01-01

Full Text Available Introduction. Desquamative interstitial pneumonia is one of the rarest idiopathic interstitial pneumonias and the rarest form of smoking-related interstitial lung diseases. It was first described by Liebow in 1965. Histologically, it is characterized by the presence of eosinophilic macrophages uniformly filling airspaces which often contain a finely granular light-brown pigment that does not stain for hemosiderin. The alveolar walls are usually mildly thickened by fibrous tissue and infiltrated by a moderate number of lymphocytes. Case Outline. Our patient was a 56-year-old male, heavy smoker, with bilateral lung infiltrations of unknown etiology and several months of discomfort in the form of dry cough and shortness of breath. Lung function tests showed a moderate restrictive ventilation disorder and a severe reduction of diffusing capacity. Since bronchoscopic specimens did not reveal lung lesion etiology, an open lung biopsy of the lower left pulmonary lobe was performed, and based on the obtained surgical material the pathohistologically diagnosis of desquamative interstitial pneumonia was established. The patient was started on corticosteroid and immunosuppressive therapy, and he ceased smoking. At the last control examination, two years after the onset of symptoms, the patient was feeling well, and high-resolution computed tomography (HRCT scan of the thorax showed regression of pathological changes. Conclusion. Although, as in our case, the majority of DIP patients improve on treatment, some patients still develop progressive irreversible fibrosis despite therapy.

On recoil energy dependent void swelling in pure copper: Theoretical treatment

International Nuclear Information System (INIS)

Golubov, S.I.; Singh, B.N.; Trinkaus, H.

2000-06-01

Over the years, an enormous amount of experimental results have been reported on damage accumulation (e.g. void swelling) in metals and alloys irradiated under vastly different recoil energy conditions. Unfortunately, however, very little is known either experimentally or theoretically about the effect of recoil energy on damage accumulation. Recently, dedicated irradiation experiments using 2.5 MeV electrons, 3.0 MeV protons and fission neutrons have been carried out to determine the effect of recoil energy on the damage accumulation behaviour in pure copper and the results have been reported in Part I of this paper (Singh, Eldrup, Horsewell, Ehrhart and Dworschak 2000). The present paper attempts to provide a theoretical framework within which the effect of recoil energy on damage accumulation behaviour can be understood. The damage accumulation under Frenkel pair production (e.g. 2.5 MeV electron) has been treated in terms of the standard rate theory (SRT) model whereas the evolution of the defect microstructure under cascade damage conditions (e.g. 3.0 MeV protons and fission neutrons) has been calculated within the framework of the production bias model (PBM). Theoretical results, in agreement with experimental results, show that the damage accumulation behaviour is very sensitive to recoil energy and under cascade damage conditions can be treated only within the framework of the PBM. The intracascade clustering of self-interstitial atoms (SIAs) and the properties of SIA clusters such as one-dimensional diffusional transport and thermal stability are found to be the main reasons for the recoil energy dependent vacancy supersaturation. The vacancy supersaturation is the main driving force for the void nucleation and void swelling. In the case of Frenkel pair production, the experimental results are found to be consistent with the SRT model with a dislocation bias value of 2 %. (au)

Smoking-related interstitial lung diseases: radiologic-pathologic correlation

International Nuclear Information System (INIS)

Hidalgo, Alberto; Franquet, Tomas; Gimenez, Ana; Pineda, Rosa; Madrid, Marta; Bordes, Ramon

2006-01-01

Smoking-related interstitial lung diseases (SRILD) are a heterogeneous group of entities of unknown cause. These diseases include desquamative interstitial pneumonia (DIP), respiratory-bronchiolitis-related interstitial lung disease (RB-ILD), pulmonary Langerhans' cell histiocytosis (LCH) and idiopathic pulmonary fibrosis (IPF). High-resolution CT is highly sensitive in the detection of abnormalities in the lung parenchyma and airways. Ground-glass attenuation can occur in DIP and RB-ILD. Whereas DIP is histologically characterized by intra-alveolar pigmented macrophages, RB-ILD shows alveolar macrophages in a patchy peribronchiolar distribution. LCH shows nodular infiltrates on histopathological examination containing varying amounts of characteristic Langerhans' histiocytes. The HRCT findings are characteristically bilateral, symmetrical and diffuse, involving the upper lobe zones with sparing of the costophrenic angles. The most prominent CT features are nodules (sometimes cavitary) measuring 1 to 10 mm in diameter, cysts and areas of ground-glass attenuation. Pathologically, IPF is characterized by its heterogeneity with areas of normal clung, alveolitis and end-stage fibrosis shown in the same biopsy specimen. High-resolution CT findings consist of honeycombing, traction bronchiectasis and intralobular interstitial thickening with subpleural and lower lung predominance. Since coexisting lesions in the same cases have been observed, a better understanding of the different smoking-related interstitial lung diseases (SRILD) allows a more confident and specific diagnosis. (orig.)

Smoking-related interstitial lung diseases: radiologic-pathologic correlation

Energy Technology Data Exchange (ETDEWEB)

Hidalgo, Alberto [Universidad Autonoma de Barcelona, Department of Radiology, Hospital de Sant Pau, Barcelona (Spain); Hospital de la Santa Creu i Sant Pau, Thoracic Radiology, Department of Radiology, Barcelona (Spain); Franquet, Tomas; Gimenez, Ana; Pineda, Rosa; Madrid, Marta [Universidad Autonoma de Barcelona, Department of Radiology, Hospital de Sant Pau, Barcelona (Spain); Bordes, Ramon [Universidad Autonoma de Barcelona, Department of Pathology, Hospital de Sant Pau, Barcelona (Spain)

2006-11-15

Smoking-related interstitial lung diseases (SRILD) are a heterogeneous group of entities of unknown cause. These diseases include desquamative interstitial pneumonia (DIP), respiratory-bronchiolitis-related interstitial lung disease (RB-ILD), pulmonary Langerhans' cell histiocytosis (LCH) and idiopathic pulmonary fibrosis (IPF). High-resolution CT is highly sensitive in the detection of abnormalities in the lung parenchyma and airways. Ground-glass attenuation can occur in DIP and RB-ILD. Whereas DIP is histologically characterized by intra-alveolar pigmented macrophages, RB-ILD shows alveolar macrophages in a patchy peribronchiolar distribution. LCH shows nodular infiltrates on histopathological examination containing varying amounts of characteristic Langerhans' histiocytes. The HRCT findings are characteristically bilateral, symmetrical and diffuse, involving the upper lobe zones with sparing of the costophrenic angles. The most prominent CT features are nodules (sometimes cavitary) measuring 1 to 10 mm in diameter, cysts and areas of ground-glass attenuation. Pathologically, IPF is characterized by its heterogeneity with areas of normal clung, alveolitis and end-stage fibrosis shown in the same biopsy specimen. High-resolution CT findings consist of honeycombing, traction bronchiectasis and intralobular interstitial thickening with subpleural and lower lung predominance. Since coexisting lesions in the same cases have been observed, a better understanding of the different smoking-related interstitial lung diseases (SRILD) allows a more confident and specific diagnosis. (orig.)

Trapping and stabilization of hydrogen atoms in intracrystalline voids. Defected calcium fluorides and Y zeolite surfaces

International Nuclear Information System (INIS)

Iton, L.E.; Turkevich, J.

1978-01-01

Using EPR spectroscopy, it has been established that H. atoms are absorbed from the gas phase when CaF 2 powder is exposed to H 2 gas in which a microwave discharge is sustained, being trapped in sites that provide unusual thermal stability. The disposition of the trapped atoms is determined by the occluded water content of the CaF 2 . For ultrapure CaF 2 , atoms are trapped in interstitial sites having A 0 = 1463 MHz; for increasing water content, two types of trapped H. atoms are discriminated, with preferential trapping in void sites (external to the regular fluorite lattice) that are associated with the H 2 O impurity. Characterization of these ''extra-lattice'' H. (and D.) atoms is presented, and their EPR parameters and behavior are discussed in detail. Failure to effect H.-D. atom exchange with D 2 gas suggests that atoms are not stabilized on the CaF 2 surface. H. atoms are trapped exclusively in ''extra-lattice'' sites when the water-containing CaF 2 is γ irradiated at 77 or 298 K indicating that the scission product atoms do not escape from the precursor void region into the regular lattice. It is concluded that the thermal stability of the ''extra-lattice'' atoms, like that of the interstitial atoms, is determined ultimately by the high activation energy for diffusion of the H. atom through the CaF 2 lattice. For comparison, results obtained from H. atoms trapped in γ-irradiated rare earth ion-exchanged Y zeolites are presented and discussed also; these ''surface'' trapped atoms do not exhibit great thermalstability. Distinctions in the H. atom formation mechanisms between the fluorides and the zeolites were deduced from the accompanying paramagnetic species formed. The intracavity electric fields in the Y zeolites have been estimated from the H. atoms hfsc contractions, and are found to be very high, about 1 V/A

Statistical study of defects caused by primary knock-on atoms in fcc Cu and bcc W using molecular dynamics

Energy Technology Data Exchange (ETDEWEB)

Warrier, M., E-mail: Manoj.Warrier@gmail.com [Computational Analysis Division, BARC, Visakhapatnam, Andhra Pradesh, 530012 (India); Bhardwaj, U.; Hemani, H. [Computational Analysis Division, BARC, Visakhapatnam, Andhra Pradesh, 530012 (India); Schneider, R. [Computational Science, Ernst-Moritz-Arndt University, D-17489 Greifswald (Germany); Mutzke, A. [Max-Planck-Institut für Plasmaphysik, D-17491 Greifswald (Germany); Valsakumar, M.C. [School for Engineering Sciences and Technology, University of Hyderabad, Gachibowli, Hyderabad, Telangana State, 500046 (India)

2015-12-15

We report on molecular Dynamics (MD) simulations carried out in fcc Cu and bcc W using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code to study (i) the statistical variations in the number of interstitials and vacancies produced by energetic primary knock-on atoms (PKA) (0.1–5 keV) directed in random directions and (ii) the in-cascade cluster size distributions. It is seen that around 60–80 random directions have to be explored for the average number of displaced atoms to become steady in the case of fcc Cu, whereas for bcc W around 50–60 random directions need to be explored. The number of Frenkel pairs produced in the MD simulations are compared with that from the Binary Collision Approximation Monte Carlo (BCA-MC) code SDTRIM-SP and the results from the NRT model. It is seen that a proper choice of the damage energy, i.e. the energy required to create a stable interstitial, is essential for the BCA-MC results to match the MD results. On the computational front it is seen that in-situ processing saves the need to input/output (I/O) atomic position data of several tera-bytes when exploring a large number of random directions and there is no difference in run-time because the extra run-time in processing data is offset by the time saved in I/O. - Highlights: • MD simulations of collision cascades in 200 random directions explored in the energy range of 1–5 keV for fcc Cu and bcc W. • 60–80 random directions must be sampled for the number of displacements produced in a collision cascade to stabilize. • In-cascade clustering of interstitials and vacancies occur. • Direction averaged distribution of interstitials and vacancies around the origin of a PKA is presented. • Comparisons with MD indicate that the recoils produced in BCA-MC simulations be checked for recombination against all vacancies created.

Atomic-scale structure of self-assembled In(Ga)As quantum rings in GaAs

NARCIS (Netherlands)

Offermans, P.; Koenraad, P.M.; Wolter, J.H.; Granados, D.; Garcia, J.M.; Fomin, V.; Gladilin, V.N.; Devreese, J.T.

2005-01-01

We present an atomic-scale analysis of the indium distribution of self-assembled In(Ga)As quantum rings (QRs) which are formed from InAs quantum dots by capping with a thin layer of GaAs and subsequent annealing. We find that the size and shape of QRs as observed by cross-sectional scanning

Radionuclide study for the interstitial lung disease

International Nuclear Information System (INIS)

Kawakami, Kenji; Mori, Yutaka; Ujita, Masuo

1991-01-01

The contribution of pulmonary nuclear medicine was evaluated in 105 patients with interstitial pulmonary diseases (IPD). Ventilation study (V) with 81m Kr, distribution of compliance in thoraco-pulmonary system (C) by 81m Kr gas bolus inhalation method, perfusion study (Q) with 99m Tc-MAA, 67 Ga scintigraphy and an assessment of pulmonary epithelial permeability with 99m Tc-DTPA aerosol were performed as nuclear medicine procedures. Pulmonary function test (%DLco, vital capacity and functional residual capacity) and blood gas analysis were also examined. Abnormalities in V were larger than that in Q which was high V/Q mismatch finding, in the interstitial pneumonia. Correlation between V/Q mismatch and PaO 2 was, therefore, not significant. %DLco was decreased in cases with larger V/Q mismatches. 67 Ga accumulated in the early stage of interstitial pneumonia when CT or chest X-ray did not show any finding. %DLco was decreased in cases with strong accumulation of 67 Ga. 67 Ga might be useful to evaluate activity of the diseases. Pulmonary epithelial permeability was assessed by 99m Tc-DTPA inhalation study. This permeability accelerated in idiopathic interstitial fibrosis and sarcoidosis. Pulmonary epithelial permeability may be useful as an indicator for epithelial cell injury. (author)

Investigation of interstitial atom ordering in energetically nonequivalent positions

CERN Document Server

Tashmetov, M Y; Mukhtarova, N N

2002-01-01

By X-ray and neutron diffraction methods the ordered structures of carbon atoms in complex carbide Ti sub 1 sub - sub x V sub x C sub 0 sub . sub 6 have been investigated. The one-phase samples have been prepared with cubic structure such as NaCl (space group Fm3m) by solid-phase vacuum sintering at 2070 K. The cubic ordered structure (sp.gr. Fd3d) with double parameter of the elementary cell in comparison with the initial one was formed after annealing the samples at 873 K (80 hours). The long-range order parameter (eta) is less than maximal in the investigated samples. It is established that at 980-1000 K the cubic ordered structure (sp.gr. Fd3m) transforms to the trigonal ordered structure (sp.gr. R3m; sp.gr. P3 sub 1 21). (author)

Euthanasia in small animals in Teresina – PI/ Eutanásia em pequenos animais em Teresina – PI

Directory of Open Access Journals (Sweden)

Ezequiel Cardoso Saraiva de Almeida

2005-06-01

Full Text Available Euthanasia is a procedure frequently utilized in small animals with the objective to minimize suffering. In this way, it was realized the survey about reasons that leave the practitioner to realize the procedure and who are these animals. It was analyzed 17406 medical records. It was observed 166 euthanasia corresponding to 0.95%. The percentage of the euthanazied dogs were 97.59% and 2.41% felines. In relation to breed 26.10% were mongrel dogs, 20.48% German sheepherd, 9.04% Brazilian fila, 7.23% Pekinese and 36.75% other breeds. In relation to age, it was observed that 60.84% have 0 – 3 year, 15.06% 3 – 6 year, 4.82% 6 – 9 year, 4.22% 9 – 12 year, 1.2% above 12 year and 13.86% unknown age. About the reason of the euthanasia, 64.60% was sacrificed due to visceral leishmaniosis (calazar, 12.65% due to distemper and 22.89% due to other diseases. It was concluded that the most animals submitted to euthanasia were young, differently of the other countries. Among principal death reasons, it was included also infectious diseases that can be prevented by adequate vaccination.A eutanásia é um procedimento utilizado com freqüência em pequenos animais, com o objetivo principal de aliviar o sofrimento. Desta forma, realizou-se um levantamento sobre os motivos que levam um veterinário a indicá-la e quais são estes animais. Foram analisadas 17406 fichas, onde se observaram 166 eutanásias o que corresponde a 0,95%. A percentagem de cães eutanasiados foi de 97,59% e a de felinos 2,41%. Em relação à raça, 26,10% dos animais era sem raça definida, 20,48% pastor alemão, 9,04% fila brasileiro, 7,23% pequinês e 36, 75% outras raças. Com respeito à idade, registrou-se que 60,84% tinham entre 0 e 3 anos, 15,06% 3 e 6 anos, 4,82% 6 e 9 anos, 4,22% 9 e 12 anos, 1,20% acima de 12 anos e 13,86% idade desconhecida. Sobre o motivo da eutanásia, 64,60% dos animais foram eutanasiados devido à Leishmaniose Visceral Canina (calazar, 12,65% devido a

[New toxicity of fotemustine: diffuse interstitial lung disease].

Science.gov (United States)

Bertrand, M; Wémeau-Stervinou, L; Gauthier, S; Auffret, M; Mortier, L

2012-04-01

Fotemustine is an alkylating cytostatic drug belonging to the nitrosourea family and is used in particular in the treatment of disseminated malignant melanoma. Herein, we report a case of interstitial lung disease associated with fotemustine. An 81-year-old man treated with fotemustine for metastatic melanoma presented acute interstitial lung disease 20 days after a fourth course of fotemustine monotherapy. The condition regressed spontaneously, with the patient returning to the clinical, radiological and blood gas status that had preceded fotemustine treatment. After other potential aetiologies had been ruled out, acute fotemustine-induced lung toxicity was considered and this treatment was definitively withdrawn. Other cytostatic agents belonging to the nitrosourea family can cause similar pictures, with a number of cases of interstitial lung disease thus being ascribed to fotemustine and dacarbazine. To our knowledge, this is the first case of interstitial lung disease induced by fotemustine monotherapy. This diagnosis should be considered where respiratory signs appear in melanoma patients undergoing fotemustine treatment. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

MD simulation of atomic displacement cascades in Fe-10 at.%Cr binary alloy

International Nuclear Information System (INIS)

Tikhonchev, M.; Svetukhin, V.; Kadochkin, A.; Gaganidze, E.

2009-01-01

Molecular dynamics simulation of atomic displacement cascades up to 20 keV has been performed in Fe-10 at.%Cr binary alloy at a temperature of 600 K. The N-body interatomic potentials of Finnis-Sinclair type were used. According to the obtained results the dependence of 'surviving' defects amount is well approximated by power function that coincides with other researchers' results. Obtained cascade efficiency for damage energy in the range from 10 to 20 keV is ∼0.2 NRT that is slightly higher than for pure α-Fe. In post-cascade area Cr fraction in interstitials is in range 2-5% that is essentially lower than Cr content in the base alloy. The results on size and amount of vacancy and interstitial clusters generated in displacement cascades are obtained. For energies of 2 keV and higher the defect cluster average size increases and it is well approximated by a linear dependence on cascade energy both for interstitials and vacancies.

MD simulation of atomic displacement cascades in Fe-10 at.%Cr binary alloy

Energy Technology Data Exchange (ETDEWEB)

Tikhonchev, M., E-mail: tikhonchev@sv.ulsu.r [Ulyanovsk State University, Leo Tolstoy Str., 42, Ulyanovsk 432970 (Russian Federation); Joint Stock Company, ' State Scientific Center Research Institute of Atomic Reactors' , 433510 Dimitrovgrad-10 (Russian Federation); Svetukhin, V.; Kadochkin, A. [Ulyanovsk State University, Leo Tolstoy Str., 42, Ulyanovsk 432970 (Russian Federation); Gaganidze, E. [Forschungszentrum Karlsruhe, IMF II, 3640, D-76021 Karlsruhe (Germany)

2009-12-15

Molecular dynamics simulation of atomic displacement cascades up to 20 keV has been performed in Fe-10 at.%Cr binary alloy at a temperature of 600 K. The N-body interatomic potentials of Finnis-Sinclair type were used. According to the obtained results the dependence of 'surviving' defects amount is well approximated by power function that coincides with other researchers' results. Obtained cascade efficiency for damage energy in the range from 10 to 20 keV is approx0.2 NRT that is slightly higher than for pure alpha-Fe. In post-cascade area Cr fraction in interstitials is in range 2-5% that is essentially lower than Cr content in the base alloy. The results on size and amount of vacancy and interstitial clusters generated in displacement cascades are obtained. For energies of 2 keV and higher the defect cluster average size increases and it is well approximated by a linear dependence on cascade energy both for interstitials and vacancies.

Molecular dynamics simulations of radiation damage in D019 Ti3Al intermetallic compound

International Nuclear Information System (INIS)

Voskoboinikov, Roman E.

2013-01-01

Molecular dynamics (MD) has been applied to simulate the radiation damage created in displacement cascades in D0 19 Ti 3 Al structural intermetallics. Collision cascades formed by the recoil of either Al or Ti primary knock-on atoms (PKA) with energy E PKA = 5, 10, 15 or 20 keV were considered in Ti 3 Al single crystals at T = 100, 300, 600 and 900 K. At least 24 different cascades for each (E PKA , T, PKA type) set were simulated. A comprehensive treatment of the modelling results has been carried out. We have evaluated the number of Frenkel pairs, fraction of Al and Ti vacancies, self-interstitial atoms and anti-sites as a function of (E PKA ,T, PKA type). Preferred formation of both Al vacancies and self-interstitial atoms in D0 19 Ti 3 Al exposed to irradiation has been detected

Self-consistent finite-temperature model of atom-laser coherence properties

International Nuclear Information System (INIS)

Fergusson, J.R.; Geddes, A.J.; Hutchinson, D.A.W.

2005-01-01

We present a mean-field model of a continuous-wave atom laser with Raman output coupling. The noncondensate is pumped at a fixed input rate which, in turn, pumps the condensate through a two-body scattering process obeying the Fermi golden rule. The gas is then coupled out by a Gaussian beam from the system, and the temperature and particle number are self-consistently evaluated against equilibrium constraints. We observe the dependence of the second-order coherence of the output upon the width of the output-coupling beam, and note that even in the presence of a highly coherent trapped gas, perfect coherence of the output matter wave is not guaranteed

Amnésia retrógrada funcional grave: relato de caso Severe functional retrograde amnesia: case report

Directory of Open Access Journals (Sweden)

Maila de Castro L. Neves

2008-01-01

Full Text Available CONTEXTO: Uma síndrome amnésica clássica caracteriza-se por evidente prejuízo da memória anterógrada, variável e temporária amnésia retrógrada, sendo as formas não-declarativas da memória poupadas. Entretanto, publicações recentes relataram casos de prejuízo desproporcional da memória retrógrada em relação à anterógrada. OBJETIVOS: Relatar o caso de um paciente de 26 anos de idade com um quadro grave de amnésia retrógrada, aparentemente sem fatores desencadeantes. MÉTODOS: Entrevista psiquiátrica e avaliação neuropsicológica. RESULTADOS: A perda de memória do paciente se estendia por toda sua vida, mas ele era capaz de adquirir e reter novas informações. Ele também apresentava prejuízos na produção e na compreensão de palavras, assim como no reconhecimento e no uso de objetos. CONCLUSÃO: A formulação diagnóstica final do caso é difícil, apontando possivelmente o contínuo existente entre a amnésia retrógrada psicogênica e a orgânica.BACKGROUND: A classic amnestic syndrome is characterized by a significant impairment of the anterograde memory, a variable and transitory retrograde amnesia with preserved non-declarative memory. However, case reports of patients with disproportionate compromise of the retrograde memory have been described in the recent literature. OBJECTIVES: To report a 26-year-old patient with a severe global retrograde amnesia with no evident triggering factor. METHODS: Psychiatric interview and neuropsychological evaluation. RESULTS: His memory loss compromised all domains of his life, although he could acquire and retain new information. He also exhibited prominent deficits in production and comprehension of common words as well as in recognition and use of objects. DISCUSSION: The final diagnostic formulation of the present case is difficult possibly indicating a continuum between psychogenic and organic retrograde amnesia.

Radiographic and high resolution CT findings of non-specific interstitial pneumonia/fibrosis

Energy Technology Data Exchange (ETDEWEB)

Kondoh, Yasuhiro; Taniguchi, Hiroyuki; Nishiyama, Satoshi [Tosei General Hospital, Seto, Aichi (Japan); Yokoi, Toyoharu; Suzuki, Ryujiro; Noda, Yasunobu; Kato, Toshiyuki; Kaneko, Michie

1999-01-01

We evaluated the radiographic and high resolution CT findings in fifteen patients with biopsy proven nonspecific interstitial pneumonia. The most common radiographic findings in NSIP were bilateral infiltrates involving alveolar pattern, interstitial pattern, and mixed alveolar-interstitial pattern, which distributed mainly in the middle and lower lung zones. Loss of lung volumes were common. The predominant findings of linear and reticular opacities on HRCT were peribronchovascular interstitial thickening, parenchymal bands, intralobular interstitial thickening, and traction bronchiectasis. Honeycombing was not noted in any patient on initial CT scans. The predominant findings of increased lung opacity were mixed pattern of ground glass opacity and consolidation. Because these findings mimic those of idiopathic pulmonary fibrosis/usual interstitial pneumonia, distinction between NSIP and IPF/UIP seems to be difficult by radiographic and HRCT findings. The response to corticosteroid therapy was good. At follow up HRCT, the pulmonary abnormalities observed on initial scans had disappeared or were diminished in most cases. Intralobular interstitial thickening and traction bronchiectasis, that have been considered to be an indicator of irreversible fibrosis, occasionally disappeared after corticosteroid therapy. (author)

Three-Dimensional Self-Assembled Photonic Crystal Waveguide

Science.gov (United States)

Baek, Kang-Hyun

Photonic crystals (PCs), two- or three-dimensionally periodic, artificial, and dielectric structures, have a specific forbidden band for electromagnetic waves, referred to as photonic bandgap (PBG). The PBG is analogous to the electronic bandgap in natural crystal structures with periodic atomic arrangement. A well-defined and embedded planar, line, or point defect within the PCs causes a break in its structural periodicity, and introduces a state in the PBG for light localization. It offers various applications in integrated optics and photonics including optical filters, sharp bending light guides and very low threshold lasers. Using nanofabrication processes, PCs of the 2-D slab-type and 3-D layer-by-layer structures have been investigated widely. Alternatively, simple and low-cost self-assembled PCs with full 3-D PBG, inverse opals, have been suggested. A template with face centered cubic closed packed structure, opal, may initially be built by self-assembly of colloidal spheres, and is selectively removed after infiltrating high refractive index materials into the interstitials of spheres. In this dissertation, the optical waveguides utilizing the 3-D self-assembled PCs are discussed. The waveguides were fabricated by microfabrication technology. For high-quality colloidal silica spheres and PCs, reliable synthesis, self-assembly, and characterization techniques were developed. Its theoretical and experimental demonstrations are provided and correlated. They suggest that the self-assembled PCs with PBG are feasible for the applications in integrated optics and photonics.

Site occupation state of deuterium atoms in fcc Fe

International Nuclear Information System (INIS)

Aoki, Katsutoshi; Machida, Akihiko; Saitoh, Hiroyuki; Hattori, Takanori; Sano-Furukawa, Asami

2015-01-01

The deuterization process of fcc Fe to form solid-solution fcc FeD x was investigated by in situ neutron diffraction measurements at high temperature and high pressure. In a completely deuterized specimen at 988 K and 6.3 GPa, deuterium atoms occupy the octahedral and tetrahedral interstitial sites with an occupancy of 0.532(9) and 0.056(5), respectively, giving a deuterium composition x of 0.64(1). During deuterization, the metal-lattice expands approximately linearly with deuterium composition at a rate of 2.21 Å 3 per deuterium atom. The minor occupation of tetrahedral site is likely driven by the intersite movement of deuterium atoms along the <111> direction in the fcc metal lattice. These results provide implications for the light elements in the Earth's core and the mechanism of hydrogen embrittlement of ferrous metals. (author)

Magnetic properties of point defect interaction with impurity atoms in Fe-Cr alloys

Science.gov (United States)

Nguyen-Manh, D.; Lavrentiev, M. Yu.; Dudarev, S. L.

2009-04-01

An integrated ab initio and statistical Monte Carlo investigation has been recently carried out to model the thermodynamic and kinetic properties of Fe-Cr alloys. We found that the conventional Fe-Cr phase diagram is not adequate at low temperature region where the magnetic contribution to the free energy plays an important role in the prediction of an ordered Fe 15Cr phase and its negative enthalpy of formation. The origin of the anomalous thermodynamic and magnetic properties of Fe-Cr alloys can be understood using a tight-binding Stoner model combined with the charge neutrality condition. We investigate the environmental dependence of magnetic moment distributions for various self-interstitial atom dumbbells configurations using spin density maps found using density functional theory calculations. The mixed dumbbell Fe-Cr and Fe-Mn binding energies are found to be positive due to magnetic interactions. Finally, we discuss the relationship between the migration energy of vacancy in Fe-Cr alloys and magnetism at the saddle point configuration.

Consequences of interstitial cystitis/bladder pain symptoms on women's work participation and income: results from a national household sample.

Science.gov (United States)

Beckett, Megan K; Elliott, Marc N; Clemens, J Quentin; Ewing, Brett; Berry, Sandra H

2014-01-01

We describe differences in work participation and income by bladder symptom impact and comorbidities among women with interstitial cystitis/bladder pain syndrome. Cross-sectional data from 2,767 respondents younger than 65 years identified with interstitial cystitis/bladder pain syndrome symptoms were analyzed. The data were taken from the RAND Interstitial Cystitis Epidemiology (RICE) survey, and included retrospective self-reports of interstitial cystitis/bladder pain syndrome impact, severity, years since onset, related comorbidities (depressive symptomatology, number of conditions), work participation and income, and personal characteristics. Multiple regressions predicted 5 current work outcomes of works now, kept from working by pain, missed work days, days worked when bothered by symptoms and real income change since symptom onset. Controlling for work status at symptom onset and personal characteristics, greater bladder symptom impact predicted a greater likelihood of not now working, kept more days from working by pain, missed more work days and working more days with symptoms. More depressive symptomatology and greater number of comorbidities predicted reduced work participation. Women experienced no growth in real income since symptom onset. Measures of symptom severity were not associated with any of the economic outcomes. Greater interstitial cystitis/bladder pain syndrome symptom impact, depressive symptomatology and count of comorbidities (but not symptom severity) were each associated with less work participation and leveling of women's long-term earnings. Management of bladder symptom impact on nonwork related activities and depressive symptomatology may improve women's work outcomes. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Reservatório de ardósia para sistemas de aproveitamento de água de chuva

Directory of Open Access Journals (Sweden)

Marcio Antonio Nogueira Andrade

Full Text Available RESUMO No contexto da crescente pressão exercida no mundo todo sobre os recursos hídricos, qualitativa e quantitativamente, o desenvolvimento de tecnologias apropriadas para sistemas de aproveitamento de água de chuva surge como alternativa promissora. Este trabalho tem como principal objetivo apresentar uma tecnologia inovadora para armazenamento de água de chuva, trazendo como modelo a construção de um reservatório executado com placas de ardósia, com capacidade para 250 m3, que faz parte de um sistema de aproveitamento de água de chuva implantado em uma instalação suinícola no Oeste Catarinense. Nesse sistema, a água de chuva é destinada para dessedentação animal e higienização das instalações. Também são apresentados, porém com menos enfoque, os dispositivos de tratamento da água de chuva desenvolvidos no projeto. Realizou-se uma análise comparativa de custos entre esse reservatório e os comumente utilizados na região de estudo. Também foram feitas análises físico-químicas e bacteriológicas da água de chuva em diferentes pontos do sistema, a fim de verificar se a qualidade da água é adequada para os usos pretendidos. A tecnologia de construção de reservatórios de ardósia apresentou rapidez e facilidade de execução e baixo custo de construção. A ardósia, além de servir de forma para a moldagem da armadura e para a argamassagem, é um material natural e abundante na região central do Estado de Santa Catarina. As análises físico-químicas e bacteriológicas mostraram a eficiência dos dispositivos de tratamento da água de chuva aplicados neste trabalho. Por fim, observou-se que a água de chuva é adequada para dessedentação animal, já que atende às condições e padrões para as águas de Classe 3 da Resolução CONAMA 357. Deste modo, a nova tecnologia apresenta grande potencial de aplicação e viabilidade econômica para a região de estudo.

Low dose rate Ir-192 interstitial brachytherapy for prostate cancer

Energy Technology Data Exchange (ETDEWEB)

Oki, Yosuke; Dokiya, Takushi; Yorozu, Atsunori; Suzuki, Takayuki; Saito, Shiro; Monma, Tetsuo; Ohki, Takahiro [National Tokyo Medical Center (Japan); Murai, Masaru; Kubo, Atsushi

2000-04-01

From December 1997 through January 1999, fifteen prostatic cancer patients were treated with low dose rate Ir-192 interstitial brachytherapy using TRUS and perineal template guidance without external radiotherapy. Up to now, as no apparent side effects were found, the safety of this treatment is suggested. In the future, in order to treat prostatic cancer patients with interstitial brachytherapy using I-125 or Pd-103, more investigation for this low dose rate Ir-192 interstitial brachytherapy is needed. (author)

Intrinsic point-defect balance in self-ion-implanted ZnO.

Science.gov (United States)

Neuvonen, Pekka T; Vines, Lasse; Svensson, Bengt G; Kuznetsov, Andrej Yu

2013-01-04

The role of excess intrinsic atoms for residual point defect balance has been discriminated by implanting Zn or O ions into Li-containing ZnO and monitoring Li redistribution and electrical resistivity after postimplant anneals. Strongly Li-depleted regions were detected in the Zn-implanted samples at depths beyond the projected range (R(p)) upon annealing ≥ 600 °C, correlating with a resistivity decrease. In contrast, similar anneals of the O-implanted samples resulted in Li accumulation at R(p) and an increased resistivity. Control samples implanted with Ar or Ne ions, yielding similar defect production as for the Zn or O implants but with no surplus of intrinsic atoms, revealed no Li depletion. Thus, the depletion of Li shows evidence of excess Zn interstitials (Zn(I)) being released during annealing of the Zn-implanted samples. These Zn(I)'s convert substitutional Li atoms (Li(Zn)) into highly mobile interstitial ones leading to the strongly Li-depleted regions. In the O-implanted samples, the high resistivity provides evidence of stable O(I)-related acceptors.

Radionuclide study for the interstitial lung disease

Energy Technology Data Exchange (ETDEWEB)

Kawakami, Kenji; Mori, Yutaka; Ujita, Masuo (Jikei Univ., Tokyo (Japan). School of Medicine)

1991-07-01

The contribution of pulmonary nuclear medicine was evaluated in 105 patients with interstitial pulmonary diseases (IPD). Ventilation study (V) with {sup 81m}Kr, distribution of compliance in thoraco-pulmonary system (C) by {sup 81m}Kr gas bolus inhalation method, perfusion study (Q) with {sup 99m}Tc-MAA, {sup 67}Ga scintigraphy and an assessment of pulmonary epithelial permeability with {sup 99m}Tc-DTPA aerosol were performed as nuclear medicine procedures. Pulmonary function test (%DLco, vital capacity and functional residual capacity) and blood gas analysis were also examined. Abnormalities in V were larger than that in Q which was high V/Q mismatch finding, in the interstitial pneumonia. Correlation between V/Q mismatch and PaO{sub 2} was, therefore, not significant. %DLco was decreased in cases with larger V/Q mismatches. {sup 67}Ga accumulated in the early stage of interstitial pneumonia when CT or chest X-ray did not show any finding. %DLco was decreased in cases with strong accumulation of {sup 67}Ga. {sup 67}Ga might be useful to evaluate activity of the diseases. Pulmonary epithelial permeability was assessed by {sup 99m}Tc-DTPA inhalation study. This permeability accelerated in idiopathic interstitial fibrosis and sarcoidosis. Pulmonary epithelial permeability may be useful as an indicator for epithelial cell injury. (author).

Controlled damaging and repair of self-organized nanostructures by atom manipulation at room temperature

International Nuclear Information System (INIS)

Gurlu, O; Houselt, A van; Thijssen, W H A; Ruitenbeek, J M van; Poelsema, B; Zandvliet, H J W

2007-01-01

The possibility of controlled local demolition and repair of the recently discovered self-organized Pt nanowires on Ge(001) surfaces has been explored. These nanowires are composed of Pt dimers, which are found to be rather weakly bound to the underlying substrate. Using this property, we demonstrate the possibility of carrying the constituting dimers of the Pt nanowires from point to point with atomic precision at room temperature. Pt dimers can be picked-up in two configurations: (i) a horizontal configuration at the tip apex, resulting in double tip images and (ii) a configuration where the Pt dimer is attached to the side of the tip apex, resulting in well-defined atomically resolved images

Point defects and irradiation in oxides: simulations at the atomic scale

International Nuclear Information System (INIS)

Crocombette, J.P.

2005-12-01

The studies done by Jean-Paul Crocombette between 1996 and 2005 in the Service de Recherches de Metallurgie Physique of the Direction de l'Energie Nucleaire in Saclay are presented in this Habilitation thesis. These works were part of the material science researches on the ageing, especially under irradiation, of oxides of interest for the nuclear industry. In this context simulation studies at the atomic scale were performed on two elementary components of ageing under irradiation : point defects and displacement cascades ; using two complementary simulation techniques : ab initio electronic structure calculations and empirical potential molecular dynamics. The first part deals with point defects : self defects (vacancies or interstitials) or hetero-atomic dopants. One first recalls the energetics of such defects in oxides, the specific features of defects calculations and the expected accuracy of these calculations. Then one presents the results obtained on uranium dioxide, oxygen in silver and amorphous silica. The second part tackles the modelling of disintegration recoil nuclei in various?displacement cascades created by crystalline matrices for actinide waste disposal. Cascade calculations give access to the amorphization mechanisms under irradiation of these materials. One thus predicts that the amorphization in zircon takes place directly in the tracks whereas in lanthanum zirconate, the amorphization proceeds through the accumulation of point defects. Finally the prospects of these studies are discussed. (author)

Investigations of lymphatic drainage from the interstitial space

Science.gov (United States)

Jayathungage Don, Tharanga; Richard Clarke Collaboration; John Cater Collaboration; Vinod Suresh Collaboration

2017-11-01

The lymphatic system is a highly complex biological system that facilitates the drainage of excess fluid in body tissues. In addition, it is an integral part of the immunological control system. Understanding the mechanisms of fluid absorption from the interstitial space and flow through the initial lymphatics is important to treat several pathological conditions. The main focus of this study is to computationally model the lymphatic drainage from the interstitial space. The model has been developed to consider a 3D lymphatic network and uses biological data to inform the creation of realistic geometries for the lymphatic capillary networks. We approximate the interstitial space as a porous region and the lymphatic vessel walls as permeable surfaces. The dynamics of the flow is approximated by Darcy's law in the interstitium and the Navier-Stokes equations in the lymphatic capillary lumen. The proposed model examines lymph drainage as a function of pressure gradient. In addition, we have examined the effects of interstitial and lymphatic wall permeabilities on the lymph drainage and the solute transportation in the model. The computational results are in accordance with the available experimental measurements.

The effect of carbon and boron on the accumulation of vacancy-oxygen complexes in silicon

International Nuclear Information System (INIS)

Akhmetov, V.D.; Bolotov, V.V.

1980-01-01

By means of IR-absorption measurements the dose dependencies of the concentrations of vacancy-oxygen complexes (VO), interstitial oxygen atoms (Osub(I)), substitutional carbon atoms (Csub(S)) and interstitial carbon-oxygen complexes (Csub(I)Osub(I)) in n- and p-type silicon irradiated with 1.1 MeV electrons have been investigated. The observed increase of the production rate of VO-complexes with the rise of carbon and boron atoms concentrations (these impurities act as sinks for silicon interstitial atoms) has been explained in terms of annihilation of the vacancies and interstitials on the oxygen atoms. The results obtained show that boron atoms are more effective sinks than carbon atoms for the interstitial silicon atoms. That seems to be connected not only with the higher probability of boron injection into interstitial position but also with the further capture of interstitial silicon atoms on the interstitial boron, i.e. with the interstitial cluster formation. (author)

Self-diffusion dynamic behavior of atomic clusters on Re(0 0 0 1) surface

Energy Technology Data Exchange (ETDEWEB)

Liu Fusheng [Department of Applied Physics, Hunan University, Changsha 410082 (China); Hu Wangyu, E-mail: wangyuhu2001cn@yahoo.com.cn [Department of Applied Physics, Hunan University, Changsha 410082 (China); Deng Huiqiu; Luo Wenhua; Xiao Shifang [Department of Applied Physics, Hunan University, Changsha 410082 (China); Yang Jianyu [Department of Maths and Physics, Hunan Institute of Engineering, Xiangtan 411104 (China)

2009-08-15

Using molecular dynamics simulations and a modified analytic embedded atom potential, the self-diffusion dynamics of rhenium atomic clusters up to seven atoms on Re(0 0 0 1) surface have been studied in the temperature ranges from 600 K to 1900 K. The simulation time varies from 20 ns to 200 ns according to the cluster sizes and the temperature. The heptamer and trimer are more stable comparing to other neighboring non-compact clusters. The diffusion coefficients of clusters are derived from the mean square displacement of cluster's mass-center, and diffusion prefactors D{sub 0} and activation energies E{sub a} are derived from the Arrhenius relation. It is found that the Arrhenius relation of the adatom can be divided into two parts at different temperature range. The activation energy of clusters increases with the increasing of the atom number in clusters. The prefactor of the heptamer is 2-3 orders of magnitude higher than a usual prefactor because of a large number of nonequivalent diffusion processes. The trimer and heptamer are the nuclei at different temperature range according to the nucleation theory.

AMPELOGRAPHIC CHARACTERIZATION OF THE AUTOCHTHONOUS GRAPE CULTIVAR “KALLMET” IN MAL��SIA E MADHE, ALBANIA

OpenAIRE

Bardhosh Ferraj; Elisabeta Susaj; Lush Susaj; Irena Kallco

2012-01-01

“Kallmet” is one of the most sprout autochthonous wine grape cultivar in the North-western and Central part of Albania. Study was conducted in three consecutive years, 2009-2011, in Malësia e Madhe, 250 m above the sea level, in the North-western part of Albania, in a 10 years old vineyard. For evaluation of the main characteristics the IPGRI Descriptors of Grapevine was used. Form of the new shoot tip of “Kallmet” is half-open, with no anthocianic coloration, and densely prostrate hairs. The...

Self-efficacy in Environmental Education: Experiences of elementary education preservice teachers

Science.gov (United States)

Gardner, Cynthia Crompton

Despite research showing Environmental Education can provide positive student outcomes in academic achievement, critical thinking, motivation and engagement (Ernst, 2007; Lieberman & Hoody, 1998; Orr, 1992; Palmer, 1998; Powers, 2004; Volk & Cheak, 2003), Environmental Education is currently not a critical element in American public school K-12 education. The present study investigates self-efficacy in Environmental Education through a mixed methods research approach. The data reveal the participants' perspectives of their sense of self-efficacy in Environmental Education. It adds to the body of work on Environmental Education and self-efficacy by specifically investigating the topics through interviews with preservice teachers. Purposeful sampling is used to identify preservice elementary education teachers in their senior year of college with a high measure of self-efficacy. Self-efficacy is measured using the Environmental Education Efficacy Belief Instrument (Sia, 1992). Forty-six preservice teachers completed the instrument. Six preservice teachers were interviewed to determine experiences that impact their self-efficacy in Environmental Education. Continual comparison and cross-case analysis are used to analyze the data. The results reveal a relationship between personal experiences with nature as a young child and current beliefs toward their personal efficacy and teaching outcome efficacy in Environmental Education. Similar to the findings of Sia (1992), the researcher discovered that preservice teachers realize that they lack sufficient knowledge and skill in Environmental Education but believe that effective teaching can increase students understanding of Environmental Education. While the preservice teachers do not believe they will teach Environmental Education as well as other subjects, they will continually seek out better ways to teach Environmental Education. Interviews with participants who had a high self-efficacy revealed the importance of

A study on applying Ra needle interstitial brachytherapy for oral cancer

International Nuclear Information System (INIS)

Yoshida, Shunichi; Komiya, Yoshiaki; Uchida, Ikuhiro; Tashiro, Kazuyoshi

1999-01-01

To investigate applicability of Ra needle interstitial brachytherapy, 93 cases of oral squamous carcinoma were examined. The patients underwent Ra needle interstitial brachytherapy as thorough therapy in our hospital. The criteria of applying Ra needle interstitial brachytherapy was diameter of within 5 cm and depth within 2 cm of tumor size. Ra needle interstitial brachytherapy was applied to 82 cases of tongue, 10 cases of oral floor and one case of lower lip carcinomas. The local control rate was 92.5%, and secondary neck metastasis was 32.3% in all cases applied Ra needle interstitial brachytherapy. The results were not bad compared with surgical treatment. However, the 5-year cumulative survival rate was 64.9%, which was not good enough at the result to obtain a good local control rate and secondary neck metastasis rate. The result was relative to low treatment result of local recurrence cases with Ra needle interstitial brachytherapy. To improve the result, it is important to distinguish local recurrence from radioinduced ulcer, and to start early secondary treatment. The cases in which cervical lymph node metastasis was found as the first examination underwent neck dessection after Ra needle interstitial brachytherapy. The 5-year cumulative survival rate was 83.3% in N1 cases and 40.6% in N2 cases, and the result of N2 cases was poorer than N1 cases with a significant difference. The results indicate that a needle having a diameter of within 5 cm, depth of within 2 cm and less than N1 can be applied during Ra needle interstitial brachytherapy for complete cure of cancer. (author)

Interstitial fluid flow in cancer: implications for disease progression and treatment

International Nuclear Information System (INIS)

Munson, Jennifer M; Shieh, Adrian C

2014-01-01

As cancer progresses, a dynamic microenvironment develops that creates and responds to cellular and biophysical cues. Increased intratumoral pressure and corresponding increases in interstitial flow from the tumor bulk to the healthy stroma is an observational hallmark of progressing cancers. Until recently, the role of interstitial flow was thought to be mostly passive in the transport and dissemination of cancer cells to metastatic sites. With research spanning the past decade, we have seen that interstitial flow has a promigratory effect on cancer cell invasion in multiple cancer types. This invasion is one mechanism by which cancers can resist therapeutics and recur, but the role of interstitial flow in cancer therapy is limited to the understanding of transport of therapeutics. Here we outline the current understanding of the role of interstitial flow in cancer and the tumor microenvironment through cancer progression and therapy. We also discuss the current role of fluid flow in the treatment of cancer, including drug transport and therapeutic strategies. By stating the current understanding of interstitial flow in cancer progression, we can begin exploring its role in therapeutic failure and treatment resistance

Is a linear probe helpful in diagnosing diseases of pulmonary interstitial spaces?

Directory of Open Access Journals (Sweden)

Natalia Buda

2017-06-01

Full Text Available In a lung ultrasound examination, interstitial lung lesions are visible as numerous B-line artifacts, and are best recorded with the use of a convex probe. Interstitial lung lesions may result from many conditions, including cardiogenic pulmonary oedema, non-cardiogenic pulmonary oedema, or interstitial lung disease. Hence difficulties in the differential diagnostics of the above clinical conditions. This article presents cases of patients suffering from interstitial lung lesions discovered in the course of lung ultrasound examination. The patients were examined with a 3.5–5.0 MHz convex probe and a 7.0–11.0 MHz linear probe. Ultrasound images have been analysed, and differences in the imaging with both probes in patients with interstitial lung lesions have been detailed. The use of a linear probe in patients with interstitial lung lesions (discovered with a convex or a micro-convex probe provides additional information on the source of the origin of the lesions.

Drug-induced interstitial lung diseases. Often forgotten

International Nuclear Information System (INIS)

Poschenrieder, F.; Stroszczynski, C.; Hamer, O.W.

2014-01-01

Drug-induced interstitial lung diseases (DILD) are probably more common than diagnosed. Due to their potential reversibility, increased vigilance towards DILD is appropriate also from the radiologist's point of view, particularly as these diseases regularly exhibit radiological correlates in high-resolution computed tomography (HRCT) of the lungs. Based on personal experience typical relatively common manifestations of DILD are diffuse alveolar damage (DAD), eosinophilic pneumonia (EP), hypersensitivity pneumonitis (HP), organizing pneumonia (OP), non-specific interstitial pneumonia (NSIP) and usual interstitial pneumonia (UIP). These patterns are presented based on case studies, whereby emphasis is placed on the clinical context. This is to highlight the relevance of interdisciplinary communication and discussion in the diagnostic field of DILD as it is a diagnosis of exclusion or of probability in most cases. Helpful differential diagnostic indications for the presence of DILD, such as an accompanying eosinophilia or increased attenuation of pulmonary consolidations in amiodarone-induced pneumopathy are mentioned and the freely available online database http://www.pneumotox.com is presented. (orig.) [de

An overview of interstitial brachytherapy and hyperthermia

International Nuclear Information System (INIS)

Brandt, B.B.; Harney, J.

1989-01-01

Interstitial thermoradiotherapy, an experimental cancer treatment that combines interstitial radiation implants (brachytherapy) and interstitial hyperthermia, is in the early stages of investigation. In accordance with the procedure used in a current national trial protocol, a 60-minute hyperthermia treatment is administered after catheters are placed into the tumor area while the patient is under general anesthesia. This is immediately followed by loading of radioactive Iridium-192 seeds into the catheters for a defined period of time. Once the prescribed radiation dose is delivered, the radioactive sources are removed and a second, 60-minute hyperthermia treatment is administered. Clinical trials with hyperthermia in combination with radiation have increased in recent years. Nurses caring for these patients need to become more knowledgeable about this investigational therapy. This paper provides an overview of the biologic rationale for this therapy, as well as a description of the delivery method and clinical application. Specific related nursing interventions are defined in a nursing protocol.23 references

Chronic interstitial lung disease in children

Directory of Open Access Journals (Sweden)

Matthias Griese

2018-02-01

Full Text Available Children's interstitial lung diseases (chILD are increasingly recognised and contain many lung developmental and genetic disorders not yet identified in adult pneumology. Worldwide, several registers have been established. The Australasian Registry Network for Orphan Lung Disease (ARNOLD has identified problems in estimating rare disease prevalence; focusing on chILD in immunocompetent patients, a period prevalence of 1.5 cases per million children and a mortality rate of 7% were determined. The chILD-EU register highlighted the workload to be covered per patient included and provided protocols for diagnosis and initial treatment, similar to the United States chILD network. Whereas case reports may be useful for young physicians to practise writing articles, cohorts of patients can catapult progress, as demonstrated by recent studies on persistent tachypnoea of infancy, hypersensitivity pneumonitis in children and interstitial lung disease related to interferonopathies from mutations in transmembrane protein 173. Translational research has linked heterozygous mutations in the ABCA3 transporter to an increased risk of interstitial lung diseases, not only in neonates, but also in older children and adults. For surfactant dysfunction disorders in infancy and early childhood, lung transplantation was reported to be as successful as in adult patients. Mutual potentiation of paediatric and adult pneumologists is mandatory in this rapidly extending field for successful future development. This brief review highlights publications in the field of paediatric interstitial lung disease as reviewed during the Clinical Year in Review session presented at the 2017 European Respiratory Society (ERS Annual Congress in Milan, Italy. It was commissioned by the ERS and critically presents progress made as well as drawbacks.

Binding energetics of substitutional and interstitial helium and di-helium defects with grain boundary structure in α-Fe

International Nuclear Information System (INIS)

Tschopp, M. A.; Gao, F.; Yang, L.; Solanki, K. N.

2014-01-01

The formation/binding energetics and length scales associated with the interaction between He atoms and grain boundaries in BCC α-Fe were explored. Ten different low Σ grain boundaries from the 〈100〉 and 〈110〉 symmetric tilt grain boundary systems were used. In this work, we then calculated formation/binding energies for 1–2 He atoms in the substitutional and interstitial sites (HeV, He 2 V, HeInt, He 2 Int) at all potential grain boundary sites within 15 Å of the boundary (52 826 simulations total). The present results provide detailed information about the interaction energies and length scales of 1–2 He atoms with grain boundaries for the structures examined. A number of interesting new findings emerge from the present study. For instance, the Σ3(112) twin boundary in BCC Fe possesses a much smaller binding energy than other boundaries, which corresponds in long time dynamics simulations to the ability of an interstitial He defect to break away from the boundary in simulations on the order of nanoseconds. Additionally, positive correlations between the calculated formation/binding energies of the He defects (R > 0.9) asserts that the local environment surrounding each site strongly influences the He defect energies and that highly accurate quantum mechanics calculations of lower order defects may be an adequate predictor of higher order defects. Various metrics to quantify or classify the local environment were compared with the He defect binding energies. The present work shows that the binding and formation energies for He defects are important for understanding the physics of He diffusion and trapping by grain boundaries, which can be important for modeling He interactions in polycrystalline steels

Binding energetics of substitutional and interstitial helium and di-helium defects with grain boundary structure in α-Fe

Energy Technology Data Exchange (ETDEWEB)

Tschopp, M. A., E-mail: mark.tschopp@gatech.edu [Dynamic Research Corporation, (on site at) U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States); Center for Advanced Vehicular Systems, Mississippi State University, Starkville, Mississippi 39762 (United States); Gao, F.; Yang, L. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Solanki, K. N. [Arizona State University, School for Engineering of Matter, Transport and Energy, Tempe, Arizona 85287 (United States)

2014-01-21

The formation/binding energetics and length scales associated with the interaction between He atoms and grain boundaries in BCC α-Fe were explored. Ten different low Σ grain boundaries from the 〈100〉 and 〈110〉 symmetric tilt grain boundary systems were used. In this work, we then calculated formation/binding energies for 1–2 He atoms in the substitutional and interstitial sites (HeV, He{sub 2}V, HeInt, He{sub 2}Int) at all potential grain boundary sites within 15 Å of the boundary (52 826 simulations total). The present results provide detailed information about the interaction energies and length scales of 1–2 He atoms with grain boundaries for the structures examined. A number of interesting new findings emerge from the present study. For instance, the Σ3(112) twin boundary in BCC Fe possesses a much smaller binding energy than other boundaries, which corresponds in long time dynamics simulations to the ability of an interstitial He defect to break away from the boundary in simulations on the order of nanoseconds. Additionally, positive correlations between the calculated formation/binding energies of the He defects (R > 0.9) asserts that the local environment surrounding each site strongly influences the He defect energies and that highly accurate quantum mechanics calculations of lower order defects may be an adequate predictor of higher order defects. Various metrics to quantify or classify the local environment were compared with the He defect binding energies. The present work shows that the binding and formation energies for He defects are important for understanding the physics of He diffusion and trapping by grain boundaries, which can be important for modeling He interactions in polycrystalline steels.

HRCT appearances of pulmonary interstitial diseases. The pathologic basis and clinical diagnostic significance

International Nuclear Information System (INIS)

Ma Daqing; Li Tieyi; Guan Yansheng; He Wen; Nie Yongkang

1999-01-01

Objective: To evaluate the CT appearances, the pathologic basis and diagnostic significance of pulmonary interstitial diseases. methods: 14 isolated lungs with interstitial diseases were obtained at autopsy and surgery. The lungs were inflated and fixed. HRCT and 1 cm thin slice soft X-ray radiograph were performed and then histologic examination was done. HRCT images of 72 cases with interstitial diseases were analysed. The HRCT appearances of 10 cases were followed up for 1.5-7.0 years. Results: According to HRCT-pathologic correlation, pulmonary interstitial diseases had the following HRCT findings: (1) Intralobular interstitial thickening (33 cases, 46%), including fine linear, reticular and radiating appearances and the interface sign. (2) Interlobular septal thickening (24 cases, 33%). (3) Thickening of bronchovesicular bundles (35 cases, 49%), with coarse, blurred or smooth bundle, and nodular shape. (4) Subpleural lines (31 cases, 43%). (5) Ground-glass opacity (22 cases, 31%) with peripheral, diffuse or locular distribution. (6) Honeycombing (27 cases, 38%), having sizes: 5 mm. Of the 10 cases with follow-up, 2 cases became normal on CT and 8 cases progressing to honeycombed lung. Conclusions: The HRCT findings of pulmonary interstitial diseases represent abnormalities of axial, peripheral and septal interstitium. Interstitial fibrosis of the lung can be differentiated from that without fibrosis by HRCT. Ground-glass opacity, intralobular interstitial thickening and subpleural lines are preliminary findings of pulmonary interstitial fibrosis

Idiopathic interstitial pneumonias: imaging-pathology correlation

International Nuclear Information System (INIS)

Ellis, Stephen M.; Hansell, David M.

2002-01-01

The terminology related to idiopathic interstitial pneumonia (IIP) remains confusing and in some cases wholly inaccurate. In addition, a greater understanding of the correlation between high-resolution computed tomography (HRCT) appearances and the corresponding histopathological changes found in the interstitial pneumonias has resulted in a crucial role for HRCT in the investigation of IIPs. The role of the radiologist is becoming increasingly important with a strong emphasis on establishing a diagnosis without resorting to lung biopsy. We aim to clarify the current classification of the IIPs highlighting their clinical, pathological and imaging characteristics in order to assist the radiologist in performing their increasingly important diagnostic role. (orig.)

Diffusion of interstitial atoms in FCC metals after irradiation with 2 MeV electrons

International Nuclear Information System (INIS)

Kornmann, H.

1980-01-01

Selfdiffusion in nickel after electron irradiation has been restudied. The diffusion velocity near the surface and the diffusion constant in the interior of the crystal have been determined as a function of radiation flux and temperature. A special method for the measurement of diffusion has been improved, which is based on radioactive tracer atoms for indication and on ion etching for the removal of thin films. To improve additionally the accuracy of the technique tracer atoms are induced into the crystal by thermal diffusion and then irradiated with 2 MeV electrons. (orig./GSCH) [de

Zinc vacancy and oxygen interstitial in ZnO revealed by sequential annealing and electron irradiation

Science.gov (United States)

Knutsen, K. E.; Galeckas, A.; Zubiaga, A.; Tuomisto, F.; Farlow, G. C.; Svensson, B. G.; Kuznetsov, A. Yu.

2012-09-01

By combining results from positron annihilation and photoluminescence spectroscopy with data from Hall effect measurements, the characteristic deep level emission centered at ˜1.75 eV and exhibiting an activation energy of thermal quenching of 11.5 meV is associated with the zinc vacancy. Further, a strong indication that oxygen interstitials act as a dominating acceptor is derived from the analysis of charge carrier losses induced by electron irradiation with variable energy below and above the threshold for Zn-atom displacement. We also demonstrate that the commonly observed green emission is related to an extrinsic acceptorlike impurity, which may be readily passivated by oxygen vacancies.

Interstitial granulomatous dermatitis (IGD)

NARCIS (Netherlands)

Tebeica, Tiberiu; Voicu, Cristiana; Patterson, James W.; Mangarov, Hristo; Lotti, T.; Wollina, Uwe; Lotti, Jacopo; França, Katlein; Batashki, Atanas; Tchernev, Georgi

2017-01-01

We report the case of a 42 years old male patient suffering from skin changes, which appeared in the last 7-8 years. Two biopsies were performed during the evolution of the lesion. Both showed similar findings that consisted in a busy dermis with interstitial, superficial and deep infiltrates of

High-dose-rate interstitial brachytherapy for the treatment of penile carcinoma

Energy Technology Data Exchange (ETDEWEB)

Petera, J.; Odrazka, K.; Zouhar, M.; Bedrosova, J.; Dolezel, M. [Dept. of Oncology and Radiotherapy, Charles Univ. Medical School and Teaching Hospital, Hradec Kralove (Czech Republic)

2004-02-01

Background: interstitial low-dose-rate (LDR) brachytherapy allows conservative treatment of T1-T2 penile carcinoma. High-dose-rate (HDR) is often considered to be dangerous for interstitial implants because of a higher risk of complications, but numerous reports suggest that results may be comparable to LDR. Nevertheless, there are no data in the literature available regarding HDR interstitial brachytherapy for carcinoma of the penis. Case report: a 64-year-old man with T1 NO MO epidermoid carcinoma of the glans is reported. Interstitial HDR brachytherapy was performed using the stainless hollow needle technique and a breast template for fixation and good geometry. The dose delivered was 18 x 3 Gy twice daily. Results: after 232 days from brachytherapy, the patient was without any evidence of the tumor, experienced no serious radiation-induced complications, and had a fully functional organ. Conclusion: HDR interstitial brachytherapy is feasible in selected case of penis carcinoma, when careful planning and small single fractions are used. (orig.)

Effect of atomic noise on optical squeezing via polarization self-rotation in a thermal vapor cell

DEFF Research Database (Denmark)

Hsu, M.T.L.; Hetet, G.; Peng, A.

2006-01-01

The traversal of an elliptically polarized optical field through a thermal vapor cell can give rise to a rotation of its polarization axis. This process, known as polarization self-rotation (PSR), has been suggested as a mechanism for producing squeezed light at atomic transition wavelengths. We ...

Measuring interstitial pH and pO2 in mouse tumors.

Science.gov (United States)

Jain, Rakesh K; Munn, Lance L; Fukumura, Dai

2013-07-01

This protocol outlines methods to measure two extravascular parameters, interstitial pH and partial pressure of oxygen (pO2), in mouse tumors. The method for measuring interstitial pH uses fluorescence ratio imaging microscopy (FRIM) of the pH-sensitive fluorescent dye 2',7'-bis-(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF). The method for measuring interstitial pO2 is based on the oxygen-dependent quenching of the phosphorescence of albumin-bound palladium meso-tetra(4-carboxyphenyl)porphyrin, and can be used to measure microvascular as well as interstitial pO2. In addition, the two methods can be used sequentially to measure both pH and pO2 in the same tissues.

Coupling sequential injection on-line preconcentration by means of a renewable microcolumn with ion-exchange beads with detection by electrothermal atomic absorption spectrometry. Comparing the performance of eluting the loaded beads with transporting them directly into the graphite tube

DEFF Research Database (Denmark)

Wang, Jianhua; Hansen, Elo Harald

2001-01-01

The design of a flow injection/sequential injection (FIA/SIA) on-line preconcentration system incorporating a renewable microcolumn with ion-exchange beads and interfaced with an electrothermal atomic absorption spectrometry (ETAAS) detector is described, and its practical applicability.......4% for the procedure in which the loaded beads are transported directly to the graphite furnace for pyrolysis and atomization, and even improved in comparison to the traditional unidirectional and bidirectional repetitive elution procedures which under comparable conditions yield R.S.D.-values of 5.8 and 4...

La interstitial defect-induced insulator-metal transition in the oxide heterostructures LaAl O3 /SrTi O3

Science.gov (United States)

Zhou, Jun; Yang, Ming; Feng, Yuan Ping; Rusydi, Andrivo

2017-11-01

Perovskite oxide interfaces have attracted tremendous research interest for their fundamental physics and promising all-oxide electronic applications. Here, based on first-principles calculations, we propose a surface La interstitial promoted interface insulator-metal transition in LaAl O3 /SrTi O3 (110). Compared with surface oxygen vacancies, which play a determining role on the insulator-metal transition of LaAl O3 /SrTi O3 (001) interfaces, we find that surface La interstitials can be more experimentally realistic and accessible for manipulation and more stable in an ambient atmospheric environment. Interestingly, these surface La interstitials also induce significant spin-splitting states with a Ti dy z/dx z character at a conducting LaAl O3 /SrTi O3 (110) interface. On the other hand, for insulating LaAl O3 /SrTi O3 (110) (<4 unit cells LaAl O3 thickness), a distortion between La (Al) and O atoms is found at the LaAl O3 side, partially compensating the polarization divergence. Our results reveal the origin of the metal-insulator transition in LaAl O3 /SrTi O3 (110) heterostructures, and also shed light on the manipulation of the superior properties of LaAl O3 /SrTi O3 (110) for different possibilities in electronic and magnetic applications.

Diffusion of interstitial oxygen in silicon and germanium: a hybrid functional study

International Nuclear Information System (INIS)

Colleoni, Davide; Pasquarello, Alfredo

2016-01-01

The minimum-energy paths for the diffusion of an interstitial O atom in silicon and germanium are studied through the nudged-elastic-band method and hybrid functional calculations. The reconsideration of the diffusion of O in silicon primarily serves the purpose of validating the procedure for studying the O diffusion in germanium. Our calculations show that the minimum energy path goes through an asymmetric transition state in both silicon and germanium. The stability of these transition states is found to be enhanced by the generation of unpaired electrons in the highest occupied single-particle states. Calculated energy barriers are 2.54 and 2.14 eV for Si and Ge, in very good agreement with corresponding experimental values of 2.53 and 2.08 eV, respectively. (paper)

Parental perceptions surrounding polio and self-reported non-participation in polio supplementary immunization activities in Karachi, Pakistan: a mixed methods study.

Science.gov (United States)

Khowaja, Asif Raza; Khan, Sher Ali; Nizam, Naveeda; Omer, Saad Bin; Zaidi, Anita

2012-11-01

To assess parent's knowledge and perceptions surrounding polio and polio vaccination, self-reported participation in polio supplementary immunization activities (SIAs) targeting children aged questionnaire was administered to assess parental knowledge of polio and participation in polio SIAs conducted in September and October 2011. Additionally, 30 parents of Pashtun ethnicity (a high-risk group) who refused to vaccinate their children were interviewed in depth to determine why. Descriptive and bivariate analyses by ethnic and socioeconomic group were performed for quantitative data; thematic analysis was conducted for qualitative interviews with Pashtun parents. Of 1017 parents surveyed, 412 (41%) had never heard of polio; 132 (13%) did not participate in one SIA and 157 (15.4%) did not participate in either SIA. Among non-participants, 34 (21.6%) reported not having been contacted by a vaccinator; 116 (73.9%) reported having refused to participate, and 7 (4.5%) reported that the child was absent from home when the vaccinator visited. Refusals clustered in low-income Pashtun (43/441; 9.8%) and high-income families of any ethnic background (71/153; 46.4%). Low-income Pashtuns were more likely to not have participated in polio SIAs than low-income non-Pashtuns (odds ratio, OR: 7.1; 95% confidence interval, CI: 3.47-14.5). Reasons commonly cited among Pashtuns for refusing vaccination included fear of sterility; lack of faith in the polio vaccine; scepticism about the vaccination programme, and fear that the vaccine might contain religiously forbidden ingredients. In Karachi, interruption of polio transmission requires integrated and participatory community interventions targeting high-risk populations.

Lung lobar volume in patients with chronic interstitial pneumonia

International Nuclear Information System (INIS)

Harada, Hisao; Koba, Hiroyuki; Saitoh, Tsukasa; Abe, Shosaku.

1997-01-01

We measured lung lobar volume by using helical computed tomography (HCT) in 23 patients with idiopathic interstitial pneumonia (IIP), 7 patients with chronic interstitial pneumonia associated with collagen vascular disease (CVD-IP), and 5 healthy volunteers HCT scanning was done at the maximal inspiratory level and the resting end-expiratory level. To measure lung lobar volume, we traced the lobar margin on HCT images with a digitizer and calculated the lobar volume with a personal computer. The lower lobar volume and several factors influencing it in chronic interstitial pneumonia were studied. At the maximal inspiratory level, the lower lobar volume as a percent of the whole lung volume was 46.8±4.13% (mean ± SD) in the volunteers, 39.5±6.19% in the patients with IIP, and 27.7±7. 86% in the patients with CVD-IP. The lower lobar volumes in the patients were significantly lower than in the volunteers. Patients with IIP in whom autoantibody tests were positive had lower lobar volumes that were very low and were similar to those of patients with CVD-IP. These data suggest that collagen vascular disease may develop in patients with interstitial pneumonia. The patients with IIP who had emphysematous changes on the CT scans had smaller decreases in total lung capacity and lower ratios of forced expiratory volume in one second to forced vital capacity than did those who had no emphysematous changes, those two groups did not differ in the ratio of lower lobar volume to whole lung volume. This suggests that emphysematous change is not factor influencing lower lobar volume in patients with chronic interstitial pneumonia. We conclude that chronic interstitial pneumonia together with very low values for lower lobar volume may be a pulmonary manifestation of collagen vascular disease. (author)

Acute ciprofloxacin-induced crystal nephropathy with granulomatous interstitial nephritis

Directory of Open Access Journals (Sweden)

R Goli

2017-01-01

Full Text Available Crystal-induced acute kidney injury (AKI is caused by the intratubular precipitation of crystals, which results in obstruction and kidney injury. Ciprofloxacin, a commonly used antibiotic, causes AKI secondary to immune-mediated interstitial injury. Rare mechanisms of ciprofloxacin-induced renal injury include crystalluria, rhabdomyolysis, and granulomatous interstitial nephritis. Clinical and experimental studies have suggested that crystalluria and crystal nephropathy due to ciprofloxacin occur in alkaline urine. Preexisting kidney function impairment, high dose of the medication, and advanced age predispose to this complication. We report a case of ciprofloxacin-induced crystal nephropathy and granulomatous interstitial nephritis in a young patient with no other predisposing factors. The patient responded to conservative treatment without the need for glucocorticoids.

Mechanisms of defect production and atomic mixing in high energy displacement cascades: A molecular dynamics study

International Nuclear Information System (INIS)

Diaz de la Rubia, T.; Guinan, M.W.

1991-01-01

We have performed molecular dynamics computer simulation studies of displacement cascades in Cu at low temperature. For 25 keV recoils we observe the splitting of a cascade into subcascades and show that cascades in Cu may lead to the formation of vacancy and interstitial dislocation loops. We discuss a new mechanism of defect production based on the observation of interstitial prismatic dislocation loop punching from cascades at 10 K. We also show that below the subcascade threshold, atomic mixing in the cascade is recoil-energy dependent and obtain a mixing efficiency that scales as the square root of the primary recoil energy. 44 refs., 12 figs

Effect of electron injection on defect reactions in irradiated silicon containing boron, carbon, and oxygen

Science.gov (United States)

Makarenko, L. F.; Lastovskii, S. B.; Yakushevich, H. S.; Moll, M.; Pintilie, I.

2018-04-01

Comparative studies employing Deep Level Transient Spectroscopy and C-V measurements have been performed on recombination-enhanced reactions between defects of interstitial type in boron doped silicon diodes irradiated with alpha-particles. It has been shown that self-interstitial related defects which are immobile even at room temperatures can be activated by very low forward currents at liquid nitrogen temperatures. Their activation is accompanied by the appearance of interstitial carbon atoms. It has been found that at rather high forward current densities which enhance BiOi complex disappearance, a retardation of Ci annealing takes place. Contrary to conventional thermal annealing of the interstitial boron-interstitial oxygen complex, the use of forward current injection helps to recover an essential part of charge carriers removed due to irradiation.

Bladder pain syndrome/interstitial cystitis in a Danish population

DEFF Research Database (Denmark)

Richter, Benedikte; Hesse, Ulrik; Hansen, Alastair B

2010-01-01

To characterize and evaluate a Danish patient population with bladder pain syndrome/interstitial cystitis (BPS/IC), using a working definition for BPS/IC incorporating six variables, and a set of criteria defined by the European Society for the Study of Interstitial Cystitis (ESSIC); to describe...... the clinical course and treatment intensity in relation to these variables....

Pancreas tumor interstitial pressure catheter measurement

Science.gov (United States)

Nieskoski, Michael D.; Gunn, Jason; Marra, Kayla; Trembly, B. Stuart; Pogue, Brian W.

2016-03-01

This paper highlights the methodology in measuring interstitial pressure in pancreatic adenocarcinoma tumors. A Millar Mikrotip pressure catheter (SPR-671) was used in this study and a system was built to amplify and filter the output signal for data collection. The Millar pressure catheter was calibrated prior to each experiment in a water column at 37°C, range of 0 to 60 inH2O (112 mmHg), resulting in a calibration factor of 33 mV / 1 inH2O. The interstitial pressures measured in two orthotopically grown pancreatic adenocarcinoma tumor were 57 mmHg and 48 mmHg, respectively. Verteporfin uptake into the pancreatic adenocarcinoma tumor was measured using a probe-based experimental dosimeter.

Californium-252 interstitial implants in carcinoma of the tongue

International Nuclear Information System (INIS)

Vtyurin, B.M.; Ivanov, V.N.; Medvedev, V.S.; Galantseva, G.F.; Abdulkadyrov, S.A.; Ivanova, L.F.; Petrovskaya, G.A.; Plichko, V.I.

1985-01-01

A clinical study using 252 Cf sources in brachytherapy of tumors began in the Research Institute of Medical Radiology of the Academy of Medical Sciences of the USSR in 1973. 252 Cf afterloading cells were utilized by the method of simple afterloading. Dosimetry and radiation protection of medical personnel were developed. To substantiate optimal therapeutic doses of 252 Cf neutrons, a correlation of dose, time, and treatment volume factors with clinical results of 252 Cf interstitial implants in carcinoma of the tongue for 47 patients with a minimum follow-up period of 1 year was studied. Forty-nine interstitial implants have been performed. Seventeen patients received 252 Cf implants alone (Group I), 17 other patients received 252 Cf implants in combination with external radiation (Group II), and 15 patients were treated with interstitial implants for recurrent or residual tumors (Groups III). Complete regression of carcinoma of the tongue was obtained in 48 patients (98%). Thirteen patients (27%) developed radiation necrosis. The therapeutic dose of neutron radiation from 252 Cf sources in interstitial radiotherapy of primary tongue carcinomas (Group I) was found to be 7 to 9 Gy. Optimal therapeutic neutron dose in combined interstitial and external radiotherapy of primary tumors (Group II) was 5 to 6 Gy with an external radiation dose of 40 Gy. For recurrent and residual tumors (Group III), favorable results were obtained with tumor doses of 6.5 to 7 Gy

Role of interstitial implantation in gynecological cancer

International Nuclear Information System (INIS)

Nori, D.; Hilaris, B.S.

1987-01-01

Recurrent cancer at any site carries a gloomy prognosis. Cancer of the cervix that recurs after radical surgery or curative radiation therapy is a perplexing problem confronting both gynecological and radiation oncologists. In the authors' series, 45% of the patients survived disease-free at 1 year and 10% survived without disease at 5 years or longer following interstitial implantation for recurrent cervical cancer. The optimal utilization of this procedure seems to depend on the site of recurrence, the extent of the disease in the pelvis, and the status of para-aortic node involvement. This retrospective analysis enabled the authors to identify the prognostic factors. The most favorable group benefited by this technique were those who presented with either central recurrence or unilateral, localized pelvic side wall recurrent disease. The least morbidity was noticed in those patients with minimal surgical manipulations at the time of the interstitial implantation. The authors recommended that only a limited and essential surgical procedure should accompany interstitial implantation, since the associated morbidity and mortality is high and survival brief

Effect of germanium doping on the annealing characteristics of oxygen and carbon-related defects in Czochralski silicon

International Nuclear Information System (INIS)

Londos, C. A.; Andrianakis, A.; Sgourou, E. N.; Emtsev, V.; Ohyama, H.

2010-01-01

This paper is devoted to the annealing studies of defects produced in carbon-rich Ge-doped Czochralski-grown Si (Cz-Si) by 2 MeV electron irradiation. The annealing temperature of vacancy-oxygen (VO) complexes, carbon interstitial-oxygen interstitial (C i O i ), and carbon interstitial-carbon substitutional (C i C s ) pairs as well as the formation temperature of vacancy-two oxygen (VO 2 ) complexes are monitored as a function of Ge concentration. It has been established that the annealing of C i O i and C i C s defects remains practically unaffected by the Ge presence, whereas the annealing temperature of VO defects and the formation temperature of VO 2 complexes are substantially lowered at Ge concentrations larger than 1x10 19 cm -3 . The hydrostatic component of elastic strains introduced by Ge atoms in the Si crystal lattice was calculated. It appears to be very small, at least insufficient to exert a pronounced effect upon the annealing behavior of radiation-produced defects. This conclusion is in line with what is observed for the C i O i and C i C s species. In the case of VO, whose annealing process in Cz-Si is concurrently conducted by two reaction paths VO+O i →VO 2 and VO+Si I →O i , we suggest that the latter reaction in Ge-doped Cz-Si is enhanced by emitting self-interstitials (Si I ) from loosely bound self-interstitial clusters predominantly formed around Ge impurity atoms. As a result, the liberation of self-interstitials at lower annealing temperatures leads to an enhanced annealing of VO defects. An enhanced formation of VO 2 complexes at lower temperatures is also discussed in terms of other reactions running in parallel with the reaction VO+Si I →O i .

Interstitial-phase precipitation in iron-base alloys: a comparative study

International Nuclear Information System (INIS)

Pelton, A.R.

1982-06-01

Recent developments have elucidated the atomistic mechanisms of precipitation of interstitial elements in simple alloy systems. However, in the more technologically important iron base alloys, interstitial phase precipitation is generally not well understood. The present experimental study was therefore designed to test the applicability of these concepts to more complex ferrous alloys. Hence, a comparative study was made of interstitial phase precipitation in ferritic Fe-Si-C and in austenitic phosphorus-containing Fe-Cr-Ni steels. These systems were subjected to a variety of quench-age thermal treatments, and the microstructural development was subsequently characterized by transmission electron microscopy

Interstitial Metabolic Monitoring During Hemorrhagic Shock

National Research Council Canada - National Science Library

Pamnani, Motilal

2004-01-01

.... We hypothesize that decompensation results from potassium-mediated vasodilation and/or loss of cardiac contractility, and thus a method of measuring interstitial potassium should be a crucial part...

Rheumatoid arthritis associated interstitial lung disease: a review

Directory of Open Access Journals (Sweden)

Deborah Assayag

2014-04-01

Full Text Available Rheumatoid arthritis is a common inflammatory disease affecting about 1% of the population. Interstitial lung disease is a serious and frequent complication of rheumatoid arthritis. Rheumatoid arthritis associated interstitial lung disease (RA-ILD is characterized by several histopathologic subtypes. This article reviews the proposed pathogenesis and risk factors for RA-ILD. We also outline the important steps involved in the work-up of RA-ILD and review the evidence for treatment and prognosis.

The idiopathic interstitial pneumonias: understanding key radiological features

Energy Technology Data Exchange (ETDEWEB)

Dixon, S. [Department of Radiology, Churchill Hospital, Old Road, Oxford OX3 7LJ (United Kingdom); Benamore, R., E-mail: Rachel.Benamore@orh.nhs.u [Department of Radiology, Churchill Hospital, Old Road, Oxford OX3 7LJ (United Kingdom)

2010-10-15

Many radiologists find it challenging to distinguish between the different interstitial idiopathic pneumonias (IIPs). The British Thoracic Society guidelines on interstitial lung disease (2008) recommend the formation of multidisciplinary meetings, with diagnoses made by combined radiological, pathological, and clinical findings. This review focuses on understanding typical and atypical radiological features on high-resolution computed tomography between the different IIPs, to help the radiologist determine when a confident diagnosis can be made and how to deal with uncertainty.

The idiopathic interstitial pneumonias: understanding key radiological features

International Nuclear Information System (INIS)

Dixon, S.; Benamore, R.

2010-01-01

Many radiologists find it challenging to distinguish between the different interstitial idiopathic pneumonias (IIPs). The British Thoracic Society guidelines on interstitial lung disease (2008) recommend the formation of multidisciplinary meetings, with diagnoses made by combined radiological, pathological, and clinical findings. This review focuses on understanding typical and atypical radiological features on high-resolution computed tomography between the different IIPs, to help the radiologist determine when a confident diagnosis can be made and how to deal with uncertainty.

Bladder pain syndrome/interstitial cystitis in a Danish population: a study using the 2008 criteria of the European Society for the Study of Interstitial Cystitis

DEFF Research Database (Denmark)

Richter, B.; Hesse, U.; Hansen, Alastair Bierre

2010-01-01

OBJECTIVE To characterize and evaluate a Danish patient population with bladder pain syndrome/interstitial cystitis (BPS/IC), using a working definition for BPS/IC incorporating six variables, and a set of criteria defined by the European Society for the Study of Interstitial Cystitis (ESSIC...

Clinical and Genetic Associations of Objectively Identified Interstitial Changes in Smokers.

Science.gov (United States)

Ash, Samuel Y; Harmouche, Rola; Putman, Rachel K; Ross, James C; Diaz, Alejandro A; Hunninghake, Gary M; Onieva Onieva, Jorge; Martinez, Fernando J; Choi, Augustine M; Lynch, David A; Hatabu, Hiroto; Rosas, Ivan O; San Jose Estepar, Raul; Washko, George R

2017-10-01

Smoking-related lung injury may manifest on CT scans as both emphysema and interstitial changes. We have developed an automated method to quantify interstitial changes and hypothesized that this measurement would be associated with lung function, quality of life, mortality, and a mucin 5B (MUC5B) polymorphism. Using CT scans from the Genetic Epidemiology of COPD Study, we objectively labeled lung parenchyma as a tissue subtype. We calculated the percentage of the lung occupied by interstitial subtypes. A total of 8,345 participants had clinical and CT scanning data available. A 5% absolute increase in interstitial changes was associated with an absolute decrease in FVC % predicted of 2.47% (P percentage of lung with interstitial changes. Objective interstitial changes on CT scans were associated with impaired lung function, worse quality of life, increased mortality, and more copies of a MUC5B promoter polymorphism, suggesting that these changes may be a marker of susceptibility to smoking-related lung injury, detectable even in those who are healthy by other measures. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Interstitial microwave hyperthermia treatment investigations

International Nuclear Information System (INIS)

Siauve, N; Lormel, C

2012-01-01

Microwave ablation also called interstitial hyperthermia is a medical procedure used in the treatment of many cancers, cardiac arrhythmias and other medical conditions. With this medical therapy, an electromagnetic source (antenna) is directly positioned in the target tissue and a sufficient power is injected to necrosis the tissue. The aim of this study is to propose a design procedure and develop the associated tools, for determining the optimal shape, dimensions, type and operating frequency of antenna according to the target volume. In this context, a 3D numerical predictive model of temperature elevation induced by the electric fields and two benches for thermal and electrical tissues properties characterization have been developed. To validate the procedure and the different tools, an experimental bench test which includes interstitial antenna, external microwave generator, phantom that represents the target tissue and measurement system of temperature and electric field has been elaborated.

Energy distributions of atoms sputtered from alkali halides by 540 eV electrons, Ch.1

International Nuclear Information System (INIS)

Overeijnder, H.; Szymonski, M.; Haring, A.; Vries, A.E. de

1978-01-01

The emission of halogen and alkali atoms, occurring under bombardment of alkali halides with electrons has been investigated. The electron energy was 540 eV and the temperature of the target was varied between room temperature and 400 0 C. The energy distribution of the emitted neutral particles was measured with a time of flight method. It was found that either diffusing interstitial halogen atoms or moving holes dominate the sputtering process above 200 0 C. Below 150 0 C alkali halides with lattice parameters s/d >= 0.33 show emission of non-thermal halogen atoms. s is the interionic space between two halogen ions in a direction and d is the diameter of a halogen atom. In general the energy distribution of the alkali and halogen atoms is thermal above 200 0 C, but not Maxwellian. (Auth.)

Pulmonary scan in evaluating alveolar-interstitial syndrome in ER

Directory of Open Access Journals (Sweden)

Giovanni Volpicelli

2006-10-01

Full Text Available Diffuse comet-tail artifacts at lung ultrasound are due to thickened interlobular septa and extravascular lung water. This condition is typical of the alveolar-interstitial syndrome due to pulmonary edema, diffuse parenchymal lung disease or ARDS. Aim of our study is to assess the potential of bedside lung ultrasound to diagnose the alveolar-interstitial syndrome in patients admitted to our emergency medicine unit. The ultrasonic feature of multiple and diffuse comet-tail artifacts was investigated during 5 months, in 121 consecutive patients admitted to our unit. Each patient was studied bedside in a supine position, by 8 antero-lateral pulmonary intercostal scans. Ultrasonic results were compared with chest radiograph and clinical outcome. Lung ultrasound showed a sensitivity of 84% and a specificity of 98% in diagnosing the radiologic alveolar-interstitial syndrome. Corresponding figures in the identification of a disease involving lung interstitium were 83% and 96%. These preliminary data show that the study of comet-tail artifacts at lung ultrasound is a method reasonably accurate for diagnosing the alveolar-interstitial syndrome at bedside. This conclusion opens the hypothesis of the usefullness of bedside lung ultrasound in the evaluation of dyspnoeic patients in the emergency setting.

Tumor interstitial fluid - a treasure trove of cancer biomarkers.

Science.gov (United States)

Gromov, Pavel; Gromova, Irina; Olsen, Charlotta J; Timmermans-Wielenga, Vera; Talman, Mai-Lis; Serizawa, Reza R; Moreira, José M A

2013-11-01

Tumor interstitial fluid (TIF) is a proximal fluid that, in addition to the set of blood soluble phase-borne proteins, holds a subset of aberrantly externalized components, mainly proteins, released by tumor cells and tumor microenvironment through various mechanisms, which include classical secretion, non-classical secretion, secretion via exosomes and membrane protein shedding. Consequently, the interstitial aqueous phase of solid tumors is a highly promising resource for the discovery of molecules associated with pathological changes in tissues. Firstly, it allows one to delve deeper into the regulatory mechanisms and functions of secretion-related processes in tumor development. Secondly, the anomalous secretion of molecules that is innate to tumors and the tumor microenvironment, being associated with cancer progression, offers a valuable source for biomarker discovery and possible targets for therapeutic intervention. Here we provide an overview of the features of tumor-associated interstitial fluids, based on recent and updated information obtained mainly from our studies of breast cancer. Data from the study of interstitial fluids recovered from several other types of cancer are also discussed. This article is a part of a Special Issue entitled: The Updated Secretome. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluation of Self-Propelled High-Energy Ultrasonic Atomizer on Azoxystrobin and Tebuconazole Application in Sunlit Greenhouse Tomatoes

Directory of Open Access Journals (Sweden)

Yan-Jie Li

2018-05-01

Full Text Available In this study, a self-propelled high-energy ultrasonic atomizer was evaluated in terms of deposition on the canopy, the loss to the ground, and fungicide residues in cherry tomato and tomato. Artificial collectors fixed to the upper side and underside of the leaves at different depths and heights were used to collect the depositions. A reliable analytical method for determination of azoxystrobin and tebuconazole in artificial collectors and residue samples was developed by using liquid chromatography triple-quadrupole mass spectrometry. The results showed that the atomizer distributed the droplets evenly throughout the greenhouse with good uniformity (CVs below 39%. The ratio of depositions on the internal and external sides was 66–83%, and the ratio of depositions on the underside and upper side was 39–50%. There were no significant differences in depositions between two different height crops. The residues of azoxystrobin and tebuconazole in tomato and cherry tomato fruits were far below the maximum residue limits at harvest time. In general, self-propelled high-energy ultrasonic atomizer used in a greenhouse could increase the depositions, especially on the underside and internal side of the canopies, and lead to a reduction of operator exposure risk.

The fraction of substitutional boron in silicon during ion implantation and thermal annealing

International Nuclear Information System (INIS)

Caturla, M.J.; Johnson, M.D.; Diaz de la Rubia, T.

1998-01-01

We present results from a kinetic Monte Carlo simulation of boron transient enhanced diffusion (TED) in silicon. Our approach avoids the use of phenomenological fits to experimental data by using a complete and self-consistent set of values for defect and dopant energetics derived mostly from ab initio calculations. The results predict that, during annealing of 40 keV B-implanted Si at 800 degree C, there exists a time window during which all the implanted boron atoms are substitutional. At earlier or later times, the interactions between free silicon self-interstitials and boron atoms drive the growth of boron clusters and result in an inactive boron fraction. The results show that the majority of boron TED takes place during the growth period of interstitial clusters and not during their dissolution. copyright 1998 American Institute of Physics

Interstitial hyperthermia using 8 MHz radiofrequency and stereotaxic brachytherapy for brain tumors

International Nuclear Information System (INIS)

Nishimura, Satoshi

1990-01-01

As a preliminary study of the interstitial hyperthermia combined with interstitial irradiation (brachytherapy) for the treatment of malignant brain tumors, we performed an experiment of interstitial hyperthermia of brain tissue of dogs. Nine afterloading tubes, four for needle electrodes and five for thermisters, were inserted in the brain tissue of dogs. Rise and stability of temperature were ascertained, and clinical safety was confirmed. Thereafter this combined therapy was applied on seven cases, in which three were malignant gliomas and four were metastatic tumors. Through the guide tubes, 192 Ir thin wires were implanted stereotaxically, and interstitial irradiation was carried out. After removal of 192 Ir wires, needle electrodes were inserted through the same tubes, and also a thermister was guided at the center of electrodes. And interstitial hyperthermia using 8 MHz radiofrequency was carried out. The results of the treatment were evaluated with CT scan based on criteria of the Japan Neurological Society. In cases of malignant gliomas, 2 PRs (partial remission), and 1 NC (no change) were obtained. In cases of metastatic tumors, 1 CR (complete remission), 2 PRs, 1 NC were obtaind. In cases of NCs, progression of tumors have been suppressed for 10 and 17 months, and still alive. As complication, transient worsening of neurological symptoms were observed in four cases (increased paresis: two cases, nausea and vomiting: two cases). The author have had an impression that interstitial hyperthermia combined with interstitial irradiation might become an effective means of treatment of brain tumors. (author)

First-Order Quantum Phase Transition for Dicke Model Induced by Atom-Atom Interaction

International Nuclear Information System (INIS)

Zhao Xiu-Qin; Liu Ni; Liang Jiu-Qing

2017-01-01

In this article, we use the spin coherent state transformation and the ground state variational method to theoretically calculate the ground function. In order to consider the influence of the atom-atom interaction on the extended Dicke model’s ground state properties, the mean photon number, the scaled atomic population and the average ground energy are displayed. Using the self-consistent field theory to solve the atom-atom interaction, we discover the system undergoes a first-order quantum phase transition from the normal phase to the superradiant phase, but a famous Dicke-type second-order quantum phase transition without the atom-atom interaction. Meanwhile, the atom-atom interaction makes the phase transition point shift to the lower atom-photon collective coupling strength. (paper)

A FIM-atom probe investigation of the bainite transformation in CrMo steel

International Nuclear Information System (INIS)

Bach, P.W.

1981-01-01

To obtain a better understanding of the role played by Cr and Mo in the bainite transformation a Field-Ion Microscope - Atom Probe was constructed in order to study the distribution of the alloying elements near various types of boundaries on atomic scale. The distribution of alloying elements measured with this instrument is not so smooth on atomic scale as suggested by microprobe analysis. In a coherent twin boundary, formed during the bainite transformation, a depletion of the substitutionals Cr and Mo and an enhancement of the C content is observed, which is in accordance with the atomic model of a B.C.C. twin. In the twin plane the interstitial sites are even larger than the F.C.C. octahedral sites and this plane can act as an effective sink for the carbon atoms from bainitic ferrite. The depletion of Cr and Mo from the twin plane is due to interface coherency. (Auth.)

SIA „Origami” saimnieciskās darbības analīze

OpenAIRE

Skalbiņš, Verners

2014-01-01

Bakalaura darba tēma ir „SIA „Origami” saimnieciskās darbības analīze”. Darbā apskatītais uzņēmums ir poligrāfijas nozares uzņēmums, kas specializējas lielformāta drukas jomā. Darba mērķis ir identificēt uzņēmuma stiprās un vājās puses, un izstrādāt priekšlikumus tā attīstībai un uzlabošanai. Mērķa sasniegšanai izvirzīti sekojoši uzdevumi: izpētīt uzņēmuma analīzes veikšanai nepieciešamo teorētisko bāzi, uz tās balstoties veikt uzņēmuma analīzi, kā arī izstrādāt secinājumus par līdzšinējo ...

An interstitial miniature antenna for localized in vivo 31P spectroscopy

International Nuclear Information System (INIS)

Hentschel, M.; Wust, P.; Faehling, H.; Richter, R.; Vogl, T.; Semmler, W.; Wolf, K.J.; Felix, R.

1996-01-01

Phosphorus spectroscopy can be used to assess response in tumor therapy and to monitor response. Methodical problems of localisation and contamination make it more difficult to interpret and reproduce the spectra. Interstitial and endoluminal spectroscopy antennas placed directly within or close to the tumor could provide help in this problem. We developed an interstitial 31 P MRS antenna together with a tuning network which can be used in thermometry catheters for hyperthermia within an internal lumen of 1.1 mm in diameter. A prototype of this type of miniature antenna suitable for use in Siemens MRI scanners at 1.5 T was described spectroscopically with regard to excitation profile, range and SNR. Results: In terms of quality, the excitation profiles of the interstitial antennas in relation to orientation correspond to those of comparable but considerably larger endocavitary antennas and catheter coils for MR imaging and spectroscopy. Maximum sensitivity was achieved by aligning the coil normal perpendicular to the B 0 field. Signal losses of up to 50% have to be reckoned with when using other orientations. The maximum range of the interstitial antenna was determined using spectroscopy and was found to be 5 mm, i.e. 9 times coil radius. The sensitivity of the studied type of interstitial antenna allows in vivo 31 P spectroscopy to be performed despite the unusually low axial dimension (coil radius r=0.55 mm). The prototype of the described interstitial antenna was used to measure an in vivo spectrum from the back muscle of a rabbit in 10 min. Nevertheless, the detection volume of at least some ml necessary for 31 P spectroscopy results mainly from the large antenna length. Conclusion: The sensitivity of the interstitial antenna needs to be further improved in order to assess treatment response in patients. (orig./MG) [de

Effects of solute interstitial elements on swelling of stainless steel

International Nuclear Information System (INIS)

Stiegler, J.O.; Leitnaker, J.M.; Bloom, E.E.

1975-01-01

High-purity stainless steel (HPS), equivalent to type 316 stainless steel in major alloy elements but with greatly reduced interstitial elements and manganese contents, was irradiated in the temperature range 725 to 875 K to fluences ranging from 1.0 to 3.5 x 10 26 neutrons/m 2 (>0.1 MeV). The HPS swelled 20 to 50 times more than commercial grade 316 stainless steel (316 SS), and about the same as commercial-purity nickel, which has about the same interstitial content as HPS. A fine-grained 316 SS in which interstitial elements but not manganese were precipitated by thermomechanical treatments also showed exaggerated swelling, approaching that of HPS, which suggests that swelling in commercial stainless steels is retarded by small amounts of interstitial elements normally present in them and not by the major alloying elements. Interstitials tend to precipitate from solution during irradiation, and bulk extractions of precipitate particles were made to evaluate the extent of the precipitation reactions. At both 643 and 853 K precipitation was clearly enhanced by irradiation significantly enough to alter the matrix composition, which suggests that swelling may be increased at high fluences over that predicted by extrapolation of lower fluence data. These observations are discussed in terms of potential behaviour of fuel cladding materials and of the validity and interpretation of accelerated schemes for simulating neutron damage. (author)

Acute Abdomen in Interstitial Ectopic Pregnancy, An Emergency Laparoscopic Treatment

Directory of Open Access Journals (Sweden)

E. Picardo

2014-01-01

Full Text Available The present case report demonstrates a laparoscopic approach to treat interstitial cornual pregnancy in emergency. Interstitial ectopic pregnancy develops in the uterine portion of the fallopian tube which accounts for 2–4% of all ectopic pregnancies and has the potential to cause life-threatening hemorrhage at rupture. The mortality rate for a woman diagnosed with such a pregnancy is 2–2.5%. Diagnosis of interstitial pregnancy is made by ultrasound. In this case a 32 year-old woman, Gravida 0 Parity 0 Living 0 Ectopic 1, presented to the emergency obstetrical room complaining acute abdominal pain. There was a history of 10 weeks of pregnancy but no pelvic ultrasound scan was performed before the access. A transvaginal ultrasound scan immediately performed demonstrated a gestational sac with viable fetus in the right interstitial region. Moreover there was an ultrasound evidence of hemoperitoneum. She was transferred to the operating room and an emergency laparoscopy surgery was performed. The postoperative course was uneventful and the patient was discharged two days after the surgery. Interstitial pregnancies present a difficult management problem with no absolute standard of care in literature. Laparoscopic technique is under study with favorable results. For our personal point of view a treatment via laparoscopy could be performed both in elective and in emergency cases.

Dislocation climb and interstitial loop growth under cascade damage irradiation

International Nuclear Information System (INIS)

Woo, C.H.; Semenov, A.A.

1993-01-01

The effects of intracascade clustering and recombination in radiation damage have been considered previously in semiquantitative calculations involving vacancy accumulation at voids, within the concept of production bias. To model void swelling and microstructural evolution quantitatively, similar effects on dislocation climb and interstitial loop growth have to be considered. In this regard, at elevated temperatures (such as in the peak-swelling temperature regime), the concentration of freely migrating vacancies is much higher than that of the interstitials, owing to the evaporation from the primary vacancy clusters (i.e. those produced by intracascade clustering). It is not immediately obvious how the dislocations can be net interstitials sinks, and hence that the observed nucleation and growth of the interstitial loops at elevated temperatures can be correctly predicted as in the conventional theory. To address these basic questions, a rate theory model is formulated in this paper, which describes the dislocation climb and loop growth in the presence of intracascade primary clusters. Within this model, conservation equations for the concentrations and average radii of the two kinds of primary cluster are derived, and the corresponding steady-state concentrations and average radii are calculated. From this, the dislocation climb velocity and interstitial loop growth rate are calculated. On the basis of the results of this calculation, some of the basic questions of production bias are discussed. (Author)

Atomic-scale investigation of point defects and hydrogen-solute atmospheres on the edge dislocation mobility in alpha iron

Energy Technology Data Exchange (ETDEWEB)

Bhatia, M. A.; Solanki, K. N., E-mail: kiran.solanki@asu.edu [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Groh, S. [Institute of Mechanics and Fluid Dynamics, TU Bergakademie Freiberg, Freiberg 09556 (Germany)

2014-08-14

In this study, we present atomistic mechanisms of 1/2 [111](11{sup ¯}0) edge dislocation interactions with point defects (hydrogen and vacancies) and hydrogen solute atmospheres in body centered cubic (bcc) iron. In metals such as iron, increases in hydrogen concentration can increase dislocation mobility and/or cleavage-type decohesion. Here, we first investigate the dislocation mobility in the presence of various point defects, i.e., change in the frictional stress as the edge dislocation interacts with (a) vacancy, (b) substitutional hydrogen, (c) one substitutional and one interstitial hydrogen, (d) interstitial hydrogen, (e) vacancy and interstitial hydrogen, and (f) two interstitial hydrogen. Second, we examine the role of a hydrogen-solute atmosphere on the rate of local dislocation velocity. The edge dislocation simulation with a vacancy in the compression side of the dislocation and an interstitial hydrogen atom at the tension side exhibit the strongest mechanical response, suggesting a higher potential barrier and hence, the higher frictional stress (i.e., ∼83% higher than the pure iron Peierls stress). In the case of a dislocation interacting with a vacancy on the compressive side, the vacancy binds with the edge dislocation, resulting in an increase in the friction stress of about 28% when compared with the Peierls stress of an edge dislocation in pure iron. Furthermore, as the applied strain increases, the vacancy migrates through a dislocation transportation mechanism by attaining a velocity of the same order as the dislocation velocity. For the case of the edge dislocation interacting with interstitial hydrogen on the tension side, the hydrogen atom jumps through one layer perpendicular to the glide plane during the pinning-unpinning process. Finally, our simulation of dislocation interactions with hydrogen show first an increase in the local dislocation velocity followed by a pinning of the dislocation core in the atmosphere, resulting in

Venous Thromboembolism and Risk of Idiopathic Interstitial Pneumonia A Nationwide Study

DEFF Research Database (Denmark)

Sode, Birgitte Margareta; Dahl, Morten; Nielsen, Sune Fallgaard

2010-01-01

Rationale: Idiopathic interstitial pneumonia is characterized by pulmonary fibrosis and high mortality. Objectives: We examined the association between ever-diagnosed venous thromboembolism and risk of incident idiopathic interstitial pneumonia. Venous thromboembolism was taken as a proxy...... Danish registries. Measurements and Main Results: Age-standardized incidence rates per 10,000 person-years for idiopathic interstitial pneumonia were higher among those ever diagnosed with venous thromboembolism (1.8; n = 158,676), pulmonary embolism (2.8; n = 70,586), and deep venous thrombosis only (1.......2; n = 88,090), than among control subjects (0.8; n = 7,260,278). Multivariate-adjusted hazard ratios for idiopathic interstitial pneumonia were 1.8 (95% confidence interval [Cl], 1.7-1.9) in those ever diagnosed with venous thromboembolism, 2.4 (95% CI, 2.3-2.6) in those ever diagnosed with pulmonary...

On the bosonic atoms

Science.gov (United States)

Amusia, M. Ya.; Chernysheva, L. V.

2018-01-01

We investigate ground state properties of atoms, in which substitute fermions - electrons by bosons, namely π --mesons. We perform some calculations in the frame of modified Hartree-Fock (HF) equation. The modification takes into account symmetry, instead of anti-symmetry of the pair identical bosons wave function. The modified HF approach thus enhances (doubles) the effect of self-action for the boson case. Therefore, we accordingly modify the HF equations by eliminating the self-action terms "by hand". The contribution of meson-meson and meson-nucleon non-Coulomb interaction is inessential at least for atoms with low and intermediate nuclear charge, which is our main subject. We found that the binding energy of pion negative ions A π - , pion atoms A π , and the number of extra bound pions ΔN π increases with the growth of nuclear charge Z. For e.g. Xe ΔN π = 4. As an example of a simple process with a pion atom, we consider photoionization that differs essentially from that for electron atoms. Namely, it is not monotonic decreasing from the threshold but has instead a prominent maximum above threshold. We study also elastic scattering of pions by pion atoms.

Interstitial meiofauna of Namib sandy beaches

African Journals Online (AJOL)

1988-03-16

Mar 16, 1988 ... Zoology Department, Institute for Coastal Research, University of Port Elizabeth, P.O. Box ... Oliff, Gardner, Turner & Sharp (1970) and later Dye, ... Wooldridge, Dye & ...... potential sources of food for interstitial organisms,.

Understanding pain and coping in women with interstitial cystitis/bladder pain syndrome.

Science.gov (United States)

Katz, Laura; Tripp, Dean A; Carr, Lesley K; Mayer, Robert; Moldwin, Robert M; Nickel, J Curtis

2017-08-01

To examine a self-regulation and coping model for interstitial cystitis/bladder pain syndrome (IC/BPS) that may help us understand the pain experience of patients with chronic IC/BPS. The model tested illness perceptions, illness-focused coping, emotional regulation, mental health and disability in a stepwise method using factor analysis and structural equation modelling. Step 1, explored the underlying constructs. Step 2, confirmed the measurement models to determine the structure/composition of the main constructs. Step 3, evaluated the model fit and specified pathways in the proposed IC/BPS self-regulation model. In all, 217 female patients with urologist diagnosed IC/BPS were recruited and diagnosed across tertiary care centres in North America. The data were collected through self-report questionnaires. An IC/BPS self-regulation model was supported. Physical disability was worsened by patient's negative perception of their illness, attempts to cope using illness-focused coping and poorer emotional regulation. Mental health was supported by perceptions that individuals could do something about their illness, using wellness-focused behavioural strategies and adaptive emotion regulation. The results clarify the complex and unique process of self-regulation in women with IC/BPS, implicating cognitive and coping targets, and highlighting emotional regulation. This knowledge should help clinicians understand and manage these patients' distress and disability. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

Interaction between interstitial atoms and 1/2 (110) edge dislocations, and its influence on the Peierls stress

International Nuclear Information System (INIS)

de Hosson, J.T.M.

1976-01-01

The positions of the metal atoms around a 1 / 2 (111) (110) edge dislocation in Mo and W are calculated using the Wilson-Johnson potentials. The boundary conditions are given by anisotropic elasticity theory. After the lattices have been relaxed the potential energy of a He atom was calculated for a grid of positions within a block around the dislocation core, which extends over six planes in the (112) direction. The He-metal potential, also developed by Johnson and Wilson was used to calculate the position with maximum energy gain for a He atom. The binding energies of the He atom in the dislocated lattice for Mo and W were 1.55 eV and 1.53 eV, respectively. The second part of the investigation concerns the Peierls stresses for a 1 / 2 (111) (110) edge dislocation in α-Fe, with and without a carbon atom. The Peierls energy and stress are calculated for this slip-system based on the method originally used by Nabarro. The Peierls stresses (at zero absolute temperature) for the lattice with and without a carbon atom, are 0.006 μ and 0.009 μ, respectively. These calculations were carried out utilizing the Wilson-Johnson potential for the Fe-Fe interaction and the Johnson potential was used for the Fe-C interaction

Local conditions for the Pauli potential in order to yield self-consistent electron densities exhibiting proper atomic shell structure

Energy Technology Data Exchange (ETDEWEB)

Finzel, Kati, E-mail: kati.finzel@liu.se [Linköpings University, IFM Department of Physics, 58183 Linköping (Sweden)

2016-01-21

The local conditions for the Pauli potential that are necessary in order to yield self-consistent electron densities from orbital-free calculations are investigated for approximations that are expressed with the help of a local position variable. It is shown that those local conditions also apply when the Pauli potential is given in terms of the electron density. An explicit formula for the Ne atom is given, preserving the local conditions during the iterative procedure. The resulting orbital-free electron density exhibits proper shell structure behavior and is in close agreement with the Kohn-Sham electron density. This study demonstrates that it is possible to obtain self-consistent orbital-free electron densities with proper atomic shell structure from simple one-point approximations for the Pauli potential at local density level.

Morphology of the Interstitial Tissue of Active and Resting Testis of the Guinea Fowl

OpenAIRE

Dharani, Palanisamy; Kumary, S. Usha; Sundaram, Venkatesan; Joseph, Cecilia; Ramesh, Geetha

2017-01-01

SUMMARY: The morphology of the interstitial tissue of sexually active and resting testis of the guinea fowl were studied. Six adult health birds of active and resting phases of reproductive cycle were used for this study. The interstitial tissue consisted of loose connective tissue, interstitial cells (Leydig cells), few connective cells, blood vessels and adrenergic nerve fibres in the present study in both active and resting testes. The interstitial tissue was compact in sexually active tes...

Economical Atomic Layer Deposition

Science.gov (United States)

Wyman, Richard; Davis, Robert; Linford, Matthew

2010-10-01

Atomic Layer Deposition is a self limiting deposition process that can produce films at a user specified height. At BYU we have designed a low cost and automated atomic layer deposition system. We have used the system to deposit silicon dioxide at room temperature using silicon tetrachloride and tetramethyl orthosilicate. Basics of atomic layer deposition, the system set up, automation techniques and our system's characterization are discussed.

Atomic bonding between metal and graphene

KAUST Repository

Wang, Hongtao; Feng, Qiong; Cheng, Yingchun; Yao, Yingbang; Wang, Qingxiao; Li, Kun; Schwingenschlö gl, Udo; Zhang, Xixiang; Yang, Wei

2013-01-01

and graphene, agreeing well with density functional theory studies. Single Cr atoms are located in the valleys of a zigzag edge, and few-atom ensembles preferentially form atomic chains by self-assembly. Low migration barriers lead to rich dynamics of metal

Atomic investigation of alloying Cr, Ti, Y additions in a grain boundary of vanadium

Energy Technology Data Exchange (ETDEWEB)

Zhang, Pengbo, E-mail: zhangpb@dlmu.edu.cn [Department of Physics, Dalian Maritime University, Dalian 116026 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Li, Xiaojie; Zhao, Jijun [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Zheng, Pengfei; Chen, Jiming [Southwestern Institute of Physics, Chengdu 610041 (China)

2016-01-15

The effect of alloying additions (Cr, Ti and Y) in a vanadium (V) ∑3 (111) grain boundary (GB) is investigated by first-principles calculations. To determine site preference and segregation properties of Cr, Ti and Y in the GB and bulk, we calculate the formation energies and segregation energies for different interstitial and substitutional sites. Cr/Ti/Y atom prefers to segregate to the substitutional sites of the GB from bulk environment, whereas Cr segregation to GB is very weak. Based on the Rice and Wang's model, Cr acts as the GB cohesion, while Ti and Y are strong embrittlers. The analysis of atomic and electronic structures provides a reasonable expansion for the embrittlement behavior. Moreover, the effect of Cr, Ti and Y in the GB on solution of interstitial impurities C, N, O, H, and He are determined. The results show that Cr restrains solution of these impurities in the GB, while Ti tends to form Ti–N complex by absorbing N impurities and Y can absorbs O and He impurities. The present calculations are helpful for understanding the behavior of alloying Cr, Ti, Y additions at the grain boundary of vanadium.

Personnel training experience in the radioactive waste management: 10 years of Moscow SIA 'RADON' international education training centre

International Nuclear Information System (INIS)

Batyukhnova, Olga; Dmitriev, Sergey; Arustamov, Artur; Ojovan, Mikhael

2007-01-01

Available in abstract form only. Full text of publication follows: The education service for specialists dealing with radioactive waste was established in Russia (former USSR) in 1983 and was based on the capabilities of two organisations: the Moscow Scientific and Industrial Association 'Radon' (SIA 'Radon') and the Chemical Department of Lomonosov's Moscow State University. These two organizations are able to offer training programs in the science fundamentals, applied research and in practical operational areas of the all pre-disposal activities of the radioactive waste management. Since 1997 this system was upgraded to the international level and now acts as International Education Training Centre (IETC) at SIA 'Radon' under the guidance of the IAEA. During 10 years more than 300 specialists from 26 European and Asian countries enhanced their knowledge and skills in radioactive waste management. The IAEA supported specialized regional training courses and workshops, fellowships, on-the-job training, and scientific visits are additional means to assure development of personnel capabilities. Efficiency of training was carefully analysed using the structural adaptation of educational process as well as factors, which have influence on education quality. Social-psychological aspects were also taken into account in assessing the overall efficiency. The analysis of the effect of individual factors and the efficiency of education activity were carried out based on attestation results and questioning attendees. A number of analytical methods were utilised such as Ishikawa's diagram method and Pareto's principle for improving of training programs and activities. (authors)

Transperineal high-dose-rate interstitial radiation therapy in the management of gynecologic malignancies

Energy Technology Data Exchange (ETDEWEB)

Itami, Jun; Hara, Ryuseke; Kozuka, Takuyou; Yamashita, Hideomi; Nakajima, Kaori; Shibata, Kouji; Abe, Yoshihisa; Fuse, Masashi; Ito, Masashi [International Medical Center of Japan, Tokyo (Japan). Dept. of Radiation Therapy and Oncology

2003-11-01

Background: High-dose-rate interstitial radiation therapy is a newly introduced modality, and its role in the management of gynecologic malignancies remains to be studied. Clinical experience in high-dose-rate interstitial radiation therapy was retrospectively investigated. Patients and Methods: Eight patients with primary and nine with recurrent gynecologic malignancies underwent high-dose-rate interstitial radiation therapy with/without external-beam irradiation. Fractional dose of the high-dose-rate interstitial radiation therapy ranged between 4 and 6 Gy with total doses of 15-54 Gy. Interstitial irradiation was performed twice daily with an interval of > 6 h. Results: 2-year local control rate was 75% for primary treatment and 47% for treatment of recurrence (p = 0.46). Maximum tumor size had a statistically significant impact on local control (p < 0.002). Grade 2 and 4 late complications were seen in five patients, and the incidence was significantly higher in patients with a larger volume enclosed by the prescribed fractional dose of high-dose-rate interstitial radiation therapy. The incidence of grade 2 and 4 complications at 18 months was 78% and 0% with a volume > 100 cm{sup 3} and {<=} 100 cm{sup 3}, respectively (p < 0.04). Conclusion: Although high-dose-rate interstitial radiation therapy is a promising modality, it must be applied cautiously to patients with bulky tumors because of the high incidence of serious complications. (orig.)

Emergent pattern formation in an interstitial biofilm

Science.gov (United States)

Zachreson, Cameron; Wolff, Christian; Whitchurch, Cynthia B.; Toth, Milos

2017-01-01

Collective behavior of bacterial colonies plays critical roles in adaptability, survivability, biofilm expansion and infection. We employ an individual-based model of an interstitial biofilm to study emergent pattern formation based on the assumptions that rod-shaped bacteria furrow through a viscous environment and excrete extracellular polymeric substances which bias their rate of motion. Because the bacteria furrow through their environment, the substratum stiffness is a key control parameter behind the formation of distinct morphological patterns. By systematically varying this property (which we quantify with a stiffness coefficient γ ), we show that subtle changes in the substratum stiffness can give rise to a stable state characterized by a high degree of local order and long-range pattern formation. The ordered state exhibits characteristics typically associated with bacterial fitness advantages, even though it is induced by changes in environmental conditions rather than changes in biological parameters. Our findings are applicable to a broad range of biofilms and provide insights into the relationship between bacterial movement and their environment, and basic mechanisms behind self-organization of biophysical systems.

Populations of subplate and interstitial neurons in fetal and adult human telencephalon.

Science.gov (United States)

Judaš, Miloš; Sedmak, Goran; Pletikos, Mihovil; Jovanov-Milošević, Nataša

2010-10-01

In the adult human telencephalon, subcortical (gyral) white matter contains a special population of interstitial neurons considered to be surviving descendants of fetal subplate neurons [Kostovic & Rakic (1980) Cytology and the time of origin of interstitial neurons in the white matter in infant and adult human and monkey telencephalon. J Neurocytol9, 219]. We designate this population of cells as superficial (gyral) interstitial neurons and describe their morphology and distribution in the postnatal and adult human cerebrum. Human fetal subplate neurons cannot be regarded as interstitial, because the subplate zone is an essential part of the fetal cortex, the major site of synaptogenesis and the 'waiting' compartment for growing cortical afferents, and contains both projection neurons and interneurons with distinct input-output connectivity. However, although the subplate zone is a transient fetal structure, many subplate neurons survive postnatally as superficial (gyral) interstitial neurons. The fetal white matter is represented by the intermediate zone and well-defined deep periventricular tracts of growing axons, such as the corpus callosum, anterior commissure, internal and external capsule, and the fountainhead of the corona radiata. These tracts gradually occupy the territory of transient fetal subventricular and ventricular zones.The human fetal white matter also contains distinct populations of deep fetal interstitial neurons, which, by virtue of their location, morphology, molecular phenotypes and advanced level of dendritic maturation, remain distinct from subplate neurons and neurons in adjacent structures (e.g. basal ganglia, basal forebrain). We describe the morphological, histochemical (nicotinamide-adenine dinucleotide phosphate-diaphorase) and immunocytochemical (neuron-specific nuclear protein, microtubule-associated protein-2, calbindin, calretinin, neuropeptide Y) features of both deep fetal interstitial neurons and deep (periventricular

Postoperative interstitial hernia as a cause of obscure incisional wound site pain

OpenAIRE

Modrzejewski, Andrzej; Śmietański, Maciej

2011-01-01

An interstitial hernia is one in which the hernia sac is located between the layers of the abdominal wall. The analysis of contemporary literature shows that interstitial hernias are most often seen in children as a type of inguinal hernia and often accompany undescended testis. The hernia sac is usually located between the external-oblique and internal-oblique muscles in a lateral-cephalic direction. The authors present 3 cases of interstitial hernia found during laparoscopic exploration of ...

Les tècniques del parlamentarisme racionalitzat en la Constitució de Tunísia de 2014

OpenAIRE

Olivetti, Marco

2015-01-01

La Constitució de Tunísia de 2014, que és el resultat del procés constituent obert l’any 2011, després de la derrota del president Ben Ali, conté una regulació detallada dels òrgans de govern que es distribueixen les funcions de direcció política (Assemblea de Representants del Poble, president de la República, cap del govern); la Constitució regula la formació, el funcionament, les competències d’aquests òrgans i les relacions entre ells. Les característiques més destacades de la forma de go...

The Objective Identification and Quantification of Interstitial Lung Abnormalities in Smokers.

Science.gov (United States)

Ash, Samuel Y; Harmouche, Rola; Ross, James C; Diaz, Alejandro A; Hunninghake, Gary M; Putman, Rachel K; Onieva, Jorge; Martinez, Fernando J; Choi, Augustine M; Lynch, David A; Hatabu, Hiroto; Rosas, Ivan O; Estepar, Raul San Jose; Washko, George R

2017-08-01

Previous investigation suggests that visually detected interstitial changes in the lung parenchyma of smokers are highly clinically relevant and predict outcomes, including death. Visual subjective analysis to detect these changes is time-consuming, insensitive to subtle changes, and requires training to enhance reproducibility. Objective detection of such changes could provide a method of disease identification without these limitations. The goal of this study was to develop and test a fully automated image processing tool to objectively identify radiographic features associated with interstitial abnormalities in the computed tomography scans of a large cohort of smokers. An automated tool that uses local histogram analysis combined with distance from the pleural surface was used to detect radiographic features consistent with interstitial lung abnormalities in computed tomography scans from 2257 individuals from the Genetic Epidemiology of COPD study, a longitudinal observational study of smokers. The sensitivity and specificity of this tool was determined based on its ability to detect the visually identified presence of these abnormalities. The tool had a sensitivity of 87.8% and a specificity of 57.5% for the detection of interstitial lung abnormalities, with a c-statistic of 0.82, and was 100% sensitive and 56.7% specific for the detection of the visual subtype of interstitial abnormalities called fibrotic parenchymal abnormalities, with a c-statistic of 0.89. In smokers, a fully automated image processing tool is able to identify those individuals who have interstitial lung abnormalities with moderate sensitivity and specificity. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

A CURIOUS CASE OF FEVER AND INTERSTITIAL LUNG DISEASE

OpenAIRE

Dr. Shahid Mahdi; Dr. Darpanarayan Hazra; Dr. Zainab Mahdi

2017-01-01

Antisynthetase syndrome is a rare chronic autoimmune inflammatory myopathy with fever, interstitial lung disease, Raynaud’s phenomenon and polyarthritis. The exact underlying cause of antisynthetase syndrome is not yet known. Diagnosis is made with presence of Jo-1 (Histydyl t RNA synthase) antigen in a patient with underlying interstitial lung disease, myositis, arthritis, Raynaud’s phenomenon and mechanic’s hand. Some of the other antisynthetase anti bodies are PL-7 (antigen – threonyl-tRNA...

Basal interstitial water pressure in laboratory debris flows over a rigid bed in an open channel

Directory of Open Access Journals (Sweden)

N. Hotta

2012-08-01

Full Text Available Measuring the interstitial water pressure of debris flows under various conditions gives essential information on the flow stress structure. This study measured the basal interstitial water pressure during debris flow routing experiments in a laboratory flume. Because a sensitive pressure gauge is required to measure the interstitial water pressure in shallow laboratory debris flows, a differential gas pressure gauge with an attached diaphragm was used. Although this system required calibration before and after each experiment, it showed a linear behavior and a sufficiently high temporal resolution for measuring the interstitial water pressure of debris flows. The values of the interstitial water pressure were low. However, an excess of pressure beyond the hydrostatic pressure was observed with increasing sediment particle size. The measured excess pressure corresponded to the theoretical excess interstitial water pressure, derived as a Reynolds stress in the interstitial water of boulder debris flows. Turbulence was thought to induce a strong shear in the interstitial space of sediment particles. The interstitial water pressure in boulder debris flows should be affected by the fine sediment concentration and the phase transition from laminar to turbulent debris flow; this should be the subject of future studies.

Identification of the interstitial Mn site in ferromagnetic (Ga,Mn)As

CERN Document Server

AUTHOR|(CDS)2093111; Wahl, Ulrich; Augustyns, Valerie; Silva, Daniel; Granadeiro Costa, Angelo Rafael; Houben, K; Edmonds, Kevin W; Gallagher, BL; Campion, RP; Van Bael, MJ; Castro Ribeiro Da Silva, Manuel; Martins Correia, Joao; Esteves De Araujo, Araujo Joao Pedro; Temst, Kristiaan; Vantomme, André; Da Costa Pereira, Lino Miguel

2015-01-01

We determined the lattice location of Mn in ferromagnetic (Ga,Mn)As using the electron emission channeling technique. We show that interstitial Mn occupies the tetrahedral site with As nearest neighbors (TAs) both before and after thermal annealing at 200 °C, whereas the occupancy of the tetrahedral site with Ga nearest neighbors (TGa) is negligible. TAs is therefore the energetically favorable site for interstitial Mn in isolated form as well as when forming complexes with substitutional Mn. These results shed new light on the long standing controversy regarding TAs versus TGa occupancy of interstitial Mn in (Ga,Mn)As.

Ab initio modeling of interactions between screw dislocations and interstitial solutes in body-centered cubic transition metals

International Nuclear Information System (INIS)

Luthi, Berengere

2017-01-01

In order to improve our understanding of alloy plasticity, it is important to describe at the atomic scale the dislocation-solute interactions and their effect on the dislocation mobility. This work focuses on the body-centered cubic (BCC) transition metals in presence of interstitial solute atoms, in particular the Fe-C system. Using Density Functional Theory (DFT) calculations, the core structure of the screw dislocation of Burgers vector b=1/2<111> was investigated in iron in presence of boron, carbon, nitrogen and oxygen solute atoms, and in BCC metals from group 5 (V, Nb, Ta) and 6 (Mo, W) in presence of carbon solutes. A core reconstruction is evidenced in iron and group 6 metals, along with a strong attractive dislocation-solute interaction energy: the dislocation goes from easy to hard configuration where the solute atoms are at the center of trigonal prisms along the dislocation line. A different behavior is observed in group 5 metals, for which the most stable configuration for the carbon atom is an octahedral site in the vicinity of the dislocation, without any core reconstruction. This group tendency is linked to the structure of mono-carbides. Consequences of the strongly attractive dislocation-solute interactions in Fe(C) were then investigated. First the equilibrium segregation close to the dislocation core was studied using a mean-field model and Monte Carlo simulations. Over a wide temperature range, from 200 to 700 K, a strong segregation is predicted with every other prismatic site occupied by a carbon atom. Then, the mobility of the dislocation in presence of carbon atoms was investigated by modeling the double-kink mechanism with DFT, in relation with experimental data obtained with transmission electron microscopy. The activation energy obtained for this atomic scale mechanism is in good agreement with experimental values for the dynamic strain aging. (author) [fr

Effect of the chemical pressure by the addition of interstitials in CePd3:

International Nuclear Information System (INIS)

Nieva, G.L.

1988-01-01

The effect of the 'chemical pressure' on the intermediate valence compound CePd 3 , is studied by means of specific heat measurements with and without magnetic field. The addition of interstitials in the cubic structure on the alloys CePd 3 A H (A = B, Be, Si) is analyzed. At low interstitial concentration the thermal and magnetic properties that characterize the evolution of the Ce valence show a universal behaviour with the volume displaced by the interstitial. For higher concentrations two different behaviours were found in the trivalent state: a) With the larger interstitials, Be and Si, the system evolves toward a long range antiferromagnetic order; b) With the smaller interstitial, B, the system evolves toward a concentrated Kondo state. (Author) [es

Flock worker's lung: chronic interstitial lung disease in the nylon flocking industry.

Science.gov (United States)

Kern, D G; Crausman, R S; Durand, K T; Nayer, A; Kuhn, C

1998-08-15

Two young men working at a nylon flocking plant in Rhode Island developed interstitial lung disease of unknown cause. Similar clusters at the same company's Canadian plant were reported previously. To define the extent, clinicopathologic features, and potential causes of the apparent disease outbreak. Case-finding survey and retrospective cohort study. Academic occupational medicine program. All workers employed at the Rhode Island plant on or after 15 June 1990. Symptomatic employees had chest radiography, pulmonary function tests, high-resolution computed tomography, and serologic testing. Those with unexplained radiographic or pulmonary function abnormalities underwent bronchoalveolar lavage, lung biopsy, or both. The case definition of "flock worker's lung" required histologic evidence of interstitial lung disease (or lavage evidence of lung inflammation) not explained by another condition. Eight cases of flock worker's lung were identified at the Rhode Island plant. Three cases were characterized by a high proportion of eosinophils (25% to 40%) in lavage fluid. Six of the seven patients who had biopsy had histologic findings of nonspecific interstitial pneumonia, and the seventh had bronchiolitis obliterans organizing pneumonia. All seven of these patients had peribronchovascular interstitial lymphoid nodules, usually with germinal centers, and most had lymphocytic bronchiolitis and interstitial fibrosis. All improved after leaving work. Review of the Canadian tissue specimens showed many similar histologic findings. Among the 165-member study cohort, a 48-fold or greater increase was seen in the sex-adjusted incidence rate of all interstitial lung disease. Work in the nylon flocking industry poses substantial risk for a previously unrecognized occupational interstitial lung disease. Nylon fiber is the suspected cause of this condition.

R-Matrix Theory of Atomic Collisions Application to Atomic, Molecular and Optical Processes

CERN Document Server

Burke, Philip George

2011-01-01

Commencing with a self-contained overview of atomic collision theory, this monograph presents recent developments of R-matrix theory and its applications to a wide-range of atomic molecular and optical processes. These developments include electron and photon collisions with atoms, ions and molecules required in the analysis of laboratory and astrophysical plasmas, multiphoton processes required in the analysis of superintense laser interactions with atoms and molecules and positron collisions with atoms and molecules required in antimatter studies of scientific and technologial importance. Basic mathematical results and general and widely used R-matrix computer programs are summarized in the appendices.

Capping Ligand Vortices as "Atomic Orbitals" in Nanocrystal Self-Assembly.

Science.gov (United States)

Waltmann, Curt; Horst, Nathan; Travesset, Alex

2017-11-28

We present a detailed analysis of the interaction between two nanocrystals capped with ligands consisting of hydrocarbon chains by united atom molecular dynamics simulations. We show that the bonding of two nanocrystals is characterized by ligand textures in the form of vortices. These results are generalized to nanocrystals of different types (differing core and ligand sizes) where the structure of the vortices depends on the softness asymmetry. We provide rigorous calculations for the binding free energy, show that these energies are independent of the chemical composition of the cores, and derive analytical formulas for the equilibrium separation. We discuss the implications of our results for the self-assembly of single-component and binary nanoparticle superlattices. Overall, our results show that the structure of the ligands completely determines the bonding of nanocrystals, fully supporting the predictions of the recently proposed Orbifold topological model.

Interstitial lung involvement in rheumatoid arthritis

Directory of Open Access Journals (Sweden)

David Vladimirovich Bestaev

2014-01-01

Full Text Available Rheumatoid arthritis (RA is a systemic autoimmune rheumatic disease of unknown etiology, characterized by chronic erosive arthritis and extraarticular manifestations. Pulmonary involvement is one of the common extraarticular manifestations of RA and may show itself as bronchial tree lesions, rheumatoid nodules, Caplan's syndrome, and lesions in the pleura or pulmonary interstitium (interstitial lung involvement (ILI. High-resolution computed tomography allows the diagnosis of ILI in RA in nearly 70% of cases although the incidence of ILI may be lower (4 to 30% depending on diagnostic methods and patient selection criteria. There are several histopathological types of ILI, the differential diagnosis of which can be troublesome. Usual interstitial pneumonia (UIP and nonspecific interstitial pneumonia are major types of RA-associated ILI. UIP-pattern ILI has a more severe course than ILI with other histological patterns. The clinical presentation of ILI may be complicated by the likely toxic effect of a number of disease-modifying antirheumatic drugs (DMARDs used to treat RA, such as methotrexate and leflunomide, and biological agents (BAs, tumor necrosis factor-α (TNF-α inhibitors. The pathogenesis of pulmonary involvement in RA and the role of synthetic DMARDs and BAs in the development of ILI call for further investigations.An extraarticular manifestation, such as ILI, affects the choice of treatment policy in patients with RA.The relevance of a study of ILI is beyond question. The paper discusses the state-of-the-art of investigations in this area.

Interstitial prostate brachytherapy. LDR-PDR-HDR

International Nuclear Information System (INIS)

Kovacs, Gyoergy; Hoskin, Peter

2013-01-01

The first comprehensive overview of interstitial brachytherapy for the management of local or locally advanced prostate cancer. Written by an interdisciplinary team who have been responsible for the successful GEC-ESTRO/EAU Teaching Course. Discusses in detail patient selection, the results of different methods, the role of imaging, and medical physics issues. Prostate brachytherapy has been the subject of heated debate among surgeons and the proponents of the various brachytherapy methods. This very first interdisciplinary book on the subject provides a comprehensive overview of innovations in low dose rate (LDR), high dose rate (HDR), and pulsed dose rate (PDR) interstitial brachytherapy for the management of local or locally advanced prostate cancer. In addition to detailed chapters on patient selection and the use of imaging in diagnostics, treatment guidance, and implantation control, background chapters are included on related medical physics issues such as treatment planning and quality assurance. The results obtained with the different treatment options and the difficult task of salvage treatment are fully discussed. All chapters have been written by internationally recognized experts in their fields who for more than a decade have formed the teaching staff responsible for the successful GEC-ESTRO/EAU Prostate Brachytherapy Teaching Course. This book will be invaluable in informing residents and others of the scientific background and potential of modern prostate brachytherapy. It will also prove a useful source of up-to-date information for those who specialize in prostate brachytherapy or intend to start an interstitial brachytherapy service.

MD study of primary damage in L10 TiAl structural intermetallics

International Nuclear Information System (INIS)

Voskoboinikov, Roman E.

2013-01-01

Computer modelling by molecular dynamics has been applied to study the radiation damage created in collision cascades in L1 0 TiAl intermetallic compound. Either Al or Ti primary knock-on atoms (PKA) with energy 5 keV ⩽ E PKA ⩽ 20 keV were introduced in the intermetallic crystals at temperatures ranging from 100 K to 900 K. At least 24 different cascade for each (E PKA , T, PKA type) set were modelled in order to simulate a random spatial and temporal distribution of PKAs and provide statistical reliability of the results. The total yield of more than 760 simulated cascades is the largest yet reported for this binary intermetallic material. A comprehensive treatment of the modelling results has been carried out. The number of Frenkel pairs, fraction of Al and Ti vacancies, self-interstitial atoms and anti-sites as a function of (E PKA , T, PKA type) has been established. Preferred formation of Al self-interstitial atoms has been detected in L1 0 TiAl structural intermetallics exposed to irradiation

Intravascular Large B-Cell Lymphoma Presenting as Interstitial Lung Disease

Directory of Open Access Journals (Sweden)

Elham Vali Khojeini

2014-01-01

Full Text Available Intravascular large B-cell lymphoma (IVLBL is a rare subtype of diffuse large B-cell lymphoma that resides in the lumen of blood vessels. Patients typically present with nonspecific findings, particularly bizarre neurologic symptoms, fever, and skin lesions. A woman presented with shortness of breath and a chest CT scan showed diffuse interstitial thickening and ground glass opacities suggestive of an interstitial lung disease. On physical exam she was noted to have splenomegaly. The patient died and at autopsy was found to have an IVLBL in her lungs as well as nearly all her organs that were sampled. Although rare, IVLBL should be included in the differential diagnosis of interstitial lung disease and this case underscores the importance of the continuation of autopsies.

The natural history of interstitial cystitis: a survey of 374 patients.

Science.gov (United States)

Koziol, J A; Clark, D C; Gittes, R F; Tan, E M

1993-03-01

A survey directed at determining the natural history of interstitial cystitis was conducted at our clinic. Information on demographics, risk factors, symptoms, pain and psychosocial factors was elicited from 374 patients who satisfied the National Institute of Arthritis, Diabetes, Digestive and Kidney Diseases criteria for interstitial cystitis and had all been diagnosed as having interstitial cystitis by a urologist. With regard to demographics, patients were predominantly female (89.8%) and white (94.1%), with a mean age of 53.8 +/- 0.7 years (standard error) and age at the first symptoms of 42.5 +/- 0.8 years. Information on 25 potential risk factors included 44.4% of the women reporting hysterectomy, 38.2% of the patients having strong sensitivities or allergic reactions to medication and only 2.7% being diabetic. With regard to interstitial cystitis symptoms, frequency and urgency were reported by 91.7% and 89.3% of the patients, respectively, while pelvic pain, pelvic pressure and bladder spasms were reported by more than 60% of respondents and burning by 56%. Location and degree of pain were also reported. Urination relieved or lessened interstitial cystitis pain for 73.6% of the patients and medication was effective for 46.8%. Other behaviors (for example hot baths, heating pads, lying down or sitting) were less effective. Conversely, stress, constrictive clothing and intercourse increased interstitial cystitis pain in more than 50% of the patients. In addition, acidic, alcoholic or carbonated beverages, and coffee or tea increased interstitial cystitis pain in more than 50% of the patients. More than 60% of the patients were unable to enjoy usual activities or were excessively fatigued and 53.7% reported depression. Travel, employment, leisure activities and sleeping were adversely affected in more than 80% of the patients. Pain location and degree differed significantly between patients with and without ulcers in the bladder. In addition, there was an

Pulmonary interstitial glycogenosis in the setting of lung growth abnormality: radiographic and pathologic correlation

Energy Technology Data Exchange (ETDEWEB)

Castillo, Monette; Vade, Aruna; Lim-Dunham, Jennifer Eden [Loyola University Health System, Department of Radiology, Maywood, IL (United States); Masuda, Emi [Henry Ford Hospital, Department of Radiology, Detroit, MI (United States); Massarani-Wafai, Rasan [Loyola University Health System, Department of Pathology, Maywood, IL (United States)

2010-09-15

Pulmonary interstitial glycogenosis (PIG) is a rare pediatric interstitial lung disease. We report a case of a term boy presenting with tachypnea at birth requiring supplemental oxygen. Chest radiographs followed by high-resolution CT (HRCT) demonstrated hyperinflation and diffuse interstitial markings interspersed with multiple cystic spaces. An open lung biopsy demonstrated a minor component of PIG superimposed upon poor alveolarization. PIG in the setting of lung growth abnormality might be more common than previously described. Additionally, radiographic findings associated with most pediatric interstitial lung diseases are nonspecific, and histopathologic correlation is essential for diagnosis. (orig.)

Multiscale modeling of radiation damage in Fe-based alloys in the fusion environment

International Nuclear Information System (INIS)

Wirth, B.D.; Odette, G.R.; Marian, J.; Ventelon, L.; Young-Vandersall, J.A.; Zepeda-Ruiz, L.A.